Patent Publication Number: US-2022238731-A1

Title: Solar cell and solar cell panel including same

Description:
TECHNICAL FIELD 
     The present disclosure relates to a solar cell and a solar cell panel including the same, and more particularly, to a solar cell with an improved structure and an improved manufacturing process and a solar cell panel including the same. 
     BACKGROUND ART 
     A plurality of solar cells is connected in series or in parallel using ribbons, wiring members, etc. and is manufactured in the form of a solar cell panel by a packaging process for protecting the plurality of solar cells. 
     In order to improve efficiency of the solar cell and an output of the solar cell panel, it is required to design various layers and electrodes included in the solar cell and the solar cell panel. A back electrode structure, in which both first and second electrodes with different polarities are disposed on a back surface of a solar cell, was proposed to efficiently use light that is incident on the front. 
     In the solar cell panel including the solar cell having the back electrode structure, the electrodes are formed on the back surface of the solar cell using printing and sputtering processes, etc., and then a solder paste is formed on the electrode. Then, ribbon, wiring members, etc. are attached to the solder paste. 
     In order to simplify the manufacturing process and reduce an electrical resistance, the electrode may include a sputtering layer and a printing layer positioned on the sputtering layer. 
     According to this, wetting of the solder paste with respect to the printing layer is not good, and thus adhesion characteristics between the printing layer and the solder paste positioned on the printing layer are not good. 
     As another example, if the electrode includes only the printing layer, a heat treatment process at a high temperature is necessary to fire the paste. Further, the characteristics of the solar cell could be changed undesirably or, in severe cases, the solar cell could be damaged due to a glass frit, etc. As another example, if the electrode includes only the sputtering layer, an electrical resistance may increase because it is difficult to sufficiently increase a thickness of the electrode. 
     As another example, if the electrode is formed using a plating process, the characteristics of the solar cell could be changed undesirably or, in severe cases, the solar cell could be damaged due to a plating solution. Further, if a pin hole, etc. exists in an insulating layer, an unwanted portion may be plated. In order to prevent this, a process becomes complicated because a seed layer needs to be separately formed prior to the plating process. In addition, it is difficult to reduce the manufacturing cost due to the cost such as material cost and waste treatment cost. 
     DISCLOSURE 
     Technical Problem 
     The present disclosure provides a solar cell and a solar cell panel including the same manufactured by a simple manufacturing process and having an excellent output. 
     More specifically, the present disclosure provides a solar cell and a solar cell panel including the same capable of improving an output and simplifying a manufacturing process by reducing an electrical resistance through an improvement in an electrode structure of the solar cell for an attachment to a wiring portion. 
     In particular, the present disclosure provides a solar cell and a solar cell panel including the same capable of improving an output and simplifying a manufacturing process by improving an electrode structure for an attachment to a wiring portion in the solar cell having a back electrode structure in which both first and second electrodes with different polarities are disposed on a back surface of the solar cell. 
     Technical Solution 
     In one aspect of the present disclosure, there is provide a solar cell panel comprising a solar cell including a semiconductor substrate, a plurality of first and second conductivity type regions positioned at the semiconductor substrate or on the semiconductor substrate, and a plurality of first and second electrodes electrically connected to the plurality of first and second conductivity type regions and extended in a first direction; a wiring portion including a plurality of first wiring members electrically connected to the plurality of first electrodes and extended in a second direction intersecting the first direction, and a plurality of second wiring members electrically connected to the plurality of second electrodes and extended in the second direction; a plurality of insulating members positioned in overlap portions of the plurality of first electrodes and the plurality of second wiring members and overlap portions of the plurality of second electrodes and the plurality of first wiring members; a sealing member surrounding the solar cell, the plurality of insulating members, and the wiring portion; a first cover member positioned on the sealing member and on one surface of the solar cell; and a second cover member positioned on the sealing member and on other surface of the solar cell. At least one of the first and second electrodes includes a main electrode portion and a connection electrode portion positioned on the main electrode portion. The connection electrode portion includes a particle connection layer formed by connecting a plurality of particles including a first metal, and a cover layer that includes a second metal different from the first metal and covers at least an outer surface of the particle connection layer. 
     The connection electrode portion may include a portion formed to extend along a longitudinal direction in the first electrode or the second electrode. 
     The connection electrode portion may be extended to connect at least the plurality of insulating members in the first electrode or the second electrode. 
     The wiring portion may be directly connected to the cover layer, or a low temperature solder paste may be directly positioned on the cover layer. 
     The solar cell panel may further comprise an intermetallic compound (IMC) layer, between the main electrode portion and the connection electrode portion, in which a metal included in the main electrode portion and the second metal are mixed. 
     The electrode may elongate along the first direction, and 100 or more electrodes may be provided in the second direction intersecting the first direction. A thickness of the connection electrode portion may be equal to or greater than 10 μm. 
     The connection electrode portion in at least one of the first and second electrodes may be comprised of a first connection electrode portion further including a solder material including the second metal and an adhesive material. 
     The connection electrode portion in at least one of the first and second electrodes may include a first connection electrode portion formed corresponding to a portion in which the first wiring member or the second wiring member is to be positioned, and a second connection electrode portion including a different material from the first connection electrode portion. 
     The first connection electrode portion may include the first metal, a solder material including the second metal, and an adhesive material. The second connection electrode portion may include the second metal, the solder material including the second metal, and a binder including a resin. 
     An adhesive force between the first connection electrode portion and the first wiring member or the second wiring member may be greater than an adhesive force between the second connection electrode portion and the first wiring member or the second wiring member. 
     A resistivity of the second connection electrode portion may be less than a resistivity of the first connection electrode portion. 
     An amount of the first metal included in the first connection electrode portion may be less than an amount of the first metal included in the second connection electrode portion. 
     The main electrode portion may elongate along the first direction, and the plurality of insulating members may be positioned on the main electrode portion and spaced apart from each other in the first direction. The connection electrode portion may contact two adjacent insulating members among the plurality of insulating members in the first direction and may be extended to connect the two adjacent insulating members. 
     The first and second electrodes may elongate along the first direction, and the plurality of insulating members may be spaced apart from each other in the first direction. The main electrode portion and the connection electrode portion may contact two adjacent insulating members among the plurality of insulating members in the first direction and may be extended to connect the two adjacent insulating members. 
     The main electrode portion and the connection electrode portion may elongate along the first direction, and the plurality of insulating members may be positioned on the main electrode portion and spaced apart from each other in the first direction. 
     The first metal may have a resistivity that is equal to or less than a resistivity of a material of the main electrode portion or the second electrode, and the second metal may include tin (Sn). 
     The first metal may include copper. 
     In another aspect of the present disclosure, there is provide a solar cell panel comprising a plurality of solar cells each including a semiconductor substrate, a conductivity type region positioned at the semiconductor substrate or on the semiconductor substrate, and an electrode electrically connected to the conductivity type region; and a wiring portion electrically connected to the electrode of each solar cell and configured to connect in series the plurality of solar cells. The electrode includes a main electrode portion comprised of a plurality of electrode layers formed by a deposition, and a connection electrode portion that is positioned on the main electrode portion and is formed by printing a metal electrode paste including a solder material. The wiring portion may be directly connected to the connection electrode portion or may be electrically connected to the connection electrode portion by a low temperature solder paste. 
     In another aspect of the present disclosure, there is provide a solar cell comprising a semiconductor substrate; a conductivity type region positioned at the semiconductor substrate or on the semiconductor substrate; and an electrode electrically connected to the conductivity type region, wherein the electrode includes a first electrode portion and a second electrode portion positioned on the first electrode portion. The second electrode portion includes a particle connection layer formed by connecting a plurality of particles including a first metal, and a cover layer that includes a second metal different from the first metal and covers at least an outer surface of the particle connection layer. The particle connection layer incudes a first portion and a second portion in which an amount of the first metal is less than that in the first portion. 
     Advantageous Effects 
     According to the present disclosure, a connection electrode portion included in an electrode can serve as an electrode for collecting and delivering electric current with a low electrical resistance, and as a solder paste for attachment to a wiring portion by including a solder material and an adhesive material. Hence, a separate solder paste layer formed corresponding to each overlap portion is not required for the substantial connection of the wiring portion and the electrode. As a result, a solar cell panel can be manufactured through the simple manufacturing process and can have excellent efficiency and output due to a low resistivity. In particular, in a solar cell having a back electrode structure in which both first and second electrodes with different polarities are provided on a back surface, the solar cell panel can efficiently improve the output and greatly simplify the manufacturing process by improving the electrode structure for the attachment to the wiring portion. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is an exploded perspective view schematically illustrating a solar cell panel according to an embodiment of the present disclosure. 
         FIG. 2  is a partial cross-sectional view conceptually illustrating two solar cells included in a solar cell panel illustrated in  FIG. 1  and a wiring portion connecting the two solar cells. 
         FIG. 3  is a cross-sectional view schematically illustrating a solar cell included in a solar cell panel illustrated in  FIG. 1 . 
         FIG. 4  is a cross-sectional view schematically illustrating a solar cell included in a solar cell panel according to a modified example of the present disclosure. 
         FIG. 5  is a cross-sectional view schematically illustrating a solar cell included in a solar cell panel according to another modified example of the present disclosure. 
         FIG. 6  is a rear plan view schematically illustrating two solar cells, an insulating member, and a wiring portion included in a solar cell panel illustrated in  FIG. 1 . 
         FIG. 7  is a partial cross-sectional view taken along line VII-VII of  FIG. 6 . 
         FIG. 8  is a partial cross-sectional view schematically illustrating two solar cells, an insulating member, and a wiring portion included in a solar cell panel according to another modified example of the present disclosure. 
         FIGS. 9 a  to 9 f    are cross-sectional views partially illustrating a method for manufacturing a solar cell panel according to an embodiment of the present disclosure. 
         FIG. 10  schematically illustrates metal particles included in a paste used for forming a connection electrode portion in a method for manufacturing a solar cell panel ( 100 ) according to an embodiment of the present disclosure. 
         FIG. 11  is a rear plan view and a partial cross-sectional view thereof schematically illustrating two solar cells, an insulating member, and a wiring portion included in a solar cell panel according to another modified example of the present disclosure. 
         FIG. 12  is a rear plan view and a partial cross-sectional view thereof schematically illustrating two solar cells, an insulating member, and a wiring portion included in a solar cell panel according to another modified example of the present disclosure. 
         FIG. 13  is a rear plan view and a partial cross-sectional view thereof schematically illustrating two solar cells, an insulating member, and a wiring portion included in a solar cell panel according to another modified example of the present disclosure. 
         FIG. 14  is a rear plan view and a partial cross-sectional view thereof schematically illustrating two solar cells, an insulating member, and a wiring portion included in a solar cell panel according to another embodiment of the present disclosure. 
         FIG. 15  is a rear plan view and a partial cross-sectional view thereof schematically illustrating two solar cells, an insulating member, and a wiring portion included in a solar cell panel according to another modified example of the present disclosure. 
     
    
    
     MODE FOR INVENTION 
     Reference will now be made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. 
     In the drawings, illustration of parts unrelated to embodiments of the present disclosure is omitted for clarity and simplicity of description. The same reference numerals designate the same or very similar components throughout the present disclosure. In the drawings, thickness, width, etc. of components are exaggerated or reduced for clarity of description, and should not be construed as limited to those illustrated in the drawings. 
     It will be understood that the terms “comprise” and/or “comprising,” or “include” and/or “including” used in the present disclosure specify the presence of stated components, but do not preclude the presence or addition of one or more other components. In addition, it will be understood that, when a component such as a layer, film, area, or plate is referred to as being “on” another component, it may be directly disposed on another component or may be disposed such that an intervening component is also between them. Accordingly, when a component such as a layer, film, area, or plate is disposed “directly on” another component, this means that there is no intervening component between the components. 
     Hereinafter, a solar cell, a solar cell panel including the same, and a method for manufacturing the solar cell panel according to embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. 
       FIG. 1  is an exploded perspective view schematically illustrating a solar cell panel according to an embodiment of the present disclosure.  FIG. 2  is a partial cross-sectional view conceptually illustrating two solar cells included in a solar cell panel illustrated in  FIG. 1  and a wiring portion connecting the two solar cells. For a clear distinction, two solar cells  10  adjacent to each other are hereinafter referred to as a first solar cell  10   a  and a second solar cell  10   b . In the present disclosure, the terms such as first, second, etc. may be used only for the purpose of distinguishing components from each other, and the present disclosure is not limited thereto. 
     Referring to  FIGS. 1 and 2 , a solar cell panel  100  according to an embodiment of the present disclosure includes a solar cell  10  and a wiring portion  140  electrically connected to the solar cell  10 . The solar cell panel  100  includes a sealing member  130  that surrounds and seals the solar cell  10  and the wiring portion  140 , a first cover member  110  positioned on the sealing member  130  and at one surface (e.g., front surface) of the solar cell  10 , and a second cover member  120  positioned on the sealing member  130  and at other surface (e.g., back surface) of the solar cell  10 . This will be described in more detail. 
     The solar cell  10  may include a semiconductor substrate (reference numeral  12  in  FIG. 3 , hereinafter the same) and first and second electrodes (reference numerals  42  and  44  in  FIG. 3 , hereinafter the same) positioned on one surface (e.g., back surface) of the semiconductor substrate  12 . This will be described in detail later with reference to  FIG. 3 . 
     In the present embodiment, the solar panel  100  includes a plurality of solar cells  10 , and the plurality of solar cells  10  may be electrically connected in series, parallel, or series-parallel by the wiring portion  140 . 
     Specifically, the wiring portion  140  may include a wiring member  142  whose at least a part overlaps the first and second electrodes  42  and  44  of the solar cell  10  and is connected to the first and second electrodes  42  and  44 , and a connecting wiring member  144  that is positioned between the solar cells  10  in a direction intersecting the wiring member  142  and is connected to the wiring member  142 . The plurality of solar cells  10  may be connected in one direction (the x-axis direction in the drawing) by the wiring member  142  and the connecting wiring member  144  to form one column (i.e., a solar cell string). The wiring member  142  and the connecting wiring member  144  will be described in more detail later with reference to  FIG. 6 . The wiring portion  140  may further include a bus bar wiring member  146  that is positioned at both ends of the solar cell string and connects the solar cell string to another solar cell string or junction box (not shown). 
     The wiring member  142 , the connecting wiring member  144 , and the bus bar wiring member  146  each may include a conductive material (e.g., a metal material). For example, the wiring member  142 , the connecting wiring member  144 , or the bus bar wiring member  146  may include a conductive core including any one of gold (Au), silver (Ag), copper (Cu), or aluminum (Al), and a conductive coating layer including tin (Sn) or an alloy including tin, positioned on the surface of the conductive core. For example, the core may be formed of copper, and the conductive coating layer may be formed of an alloy (e.g., SnBiAg) containing tin. However, the present disclosure is not limited thereto, and the material, shape, connection structure, etc. of the wiring member  142 , the connecting wiring member  144 , or the bus bar wiring member  146  may be variously changed. In addition, neighboring solar cells  10  may be connected by only the wiring member  142  without providing the connecting wiring member  144 . 
     The sealing member  130  may include a first sealing member  131  positioned on the front surface of the solar cell  10  connected by the wiring member  142 , and a second sealing member  132  positioned on the back surface of the solar cell  10 . The first sealing member  131  and the second sealing member  132  prevent moisture and oxygen from being introduced and chemically couple components of the solar cell panel  100 . The first and second sealing members  131  and  132  may be made of an insulating material with transparency and adhesiveness. For example, the first sealing member  131  and the second sealing member  132  may be formed using ethylene vinyl acetate copolymer (EVA) resin, polyvinyl butyral, silicon resin, ester-based resin, olefin-based resin, or the like. The second cover member  120 , the second sealing member  132 , the solar cell  10 , the wiring portion  140 , the first sealing member  131 , and the first cover member  110  may be integrated by a lamination process or the like using the first and second sealing members  131  and  132  to form the solar cell panel  100 . 
     The first cover member  110  is positioned on the first sealing member  131  to form the front surface of the solar cell panel  100 , and the second cover member  120  is positioned on the second sealing member  132  to form the back surface of the solar cell panel  100 . The first cover member  110  and the second cover member  120  each may be made of an insulating material capable of protecting the solar cell  10  from external shock, moisture, ultraviolet rays, or the like. The first cover member  110  may be made of a light transmitting material capable of transmitting light, and the second cover member  120  may be made of a sheet consisting of a light transmitting material, a non-light transmitting material, or a reflective material, etc. For example, the first cover member  110  may be formed of a glass substrate or the like, and the second cover member  120  may be formed of a film, a sheet or the like. The second cover member  120  may have a TPT (Tedlar/PET/Tedlar) type, or include a polyvinylidene fluoride (PVDF) resin layer formed on at least one surface of a base film (e.g., polyethylene terephthalate (PET)). 
     However, the present disclosure is not limited thereto. Accordingly, the first and second sealing members  131  and  132 , the first cover member  110 , or the second cover member  120  may include various materials other than those described above, and may have various shapes. For example, the first cover member  110  or the second cover member  120  may have various shapes (for example, a substrate, a film, a sheet, etc.) or materials. 
     After the solar cell  10  included in the solar cell panel  100  according to an embodiment of the present disclosure is described in detail with reference to  FIG. 3 , the wiring portion  140  and an insulating member (reference numeral IP in  FIG. 6 , hereinafter the same) connected to the solar cell  10  are described in detail with reference to  FIGS. 6 and 7 . 
       FIG. 3  is a cross-sectional view schematically illustrating the solar cell  10  included in the solar cell panel  100  illustrated in  FIG. 1 . For example,  FIG. 3  illustrates that the first and second electrodes  42  and  44  each include main electrode portions (first electrode portions)  42   a  and  44   a  and connection electrode portions (second electrode portions)  42   b  and  44   b , by way of example. 
     Referring to  FIG. 3 , the solar cell  10  according to the present embodiment includes a semiconductor substrate  12 , first and second conductivity type regions  32  and  34  formed at or on one surface (e.g., the back surface) of the semiconductor substrate  12 , first and second electrodes  42  and  44  respectively connected to the first and second conductivity type regions  32  and  34  on the one surface of the semiconductor substrate. As described above, the solar cell  10  may have a back electrode structure in which the first and second conductivity type regions  32  and  34  and the first and second electrodes  42  and  44  related to carriers of opposite polarities are positioned on the back surface of the semiconductor substrate  12  to be spaced apart from each other. 
     For example, the semiconductor substrate  12  may include a base region  12   a  formed of a crystalline semiconductor (e.g., a single crystal or polycrystalline semiconductor, for example, a single crystal or polycrystalline silicon, in particular, the single crystal silicon) including a first or second conductivity type dopant. As described above, the solar cell  10  based on the base region  12   a  or the semiconductor substrate  12  having fewer defects due to high crystallinity has excellent electrical characteristics. 
     A front surface field region  12   b  may be positioned on the front surface of the semiconductor substrate  12 . For example, the front surface field region  12   b  is a doped region having the same conductivity type as the base region  12   a  and having a higher doping concentration than the base region  12   a , and may form a part of the semiconductor substrate  12 . However, the present disclosure is not limited thereto. Thus, various modifications are possible. For example, the front surface field region  12   b  may be a semiconductor layer positioned separately from the semiconductor substrate  12 , or may be formed of an oxide layer, etc. having a fixed charge or the like without a dopant. 
     In addition, the front surface of the semiconductor substrate  12  has an anti-reflection structure (for example, a pyramid-shaped texturing structure formed of (111) plane of the semiconductor substrate  12 ) for preventing reflection, and thus can minimize the reflection. In addition, the back surface of the semiconductor substrate  12  is formed of a mirror polished surface to have a smaller surface roughness than that of the front surface, and thus can improve passivation characteristics. However, the present disclosure is not limited thereto and can be variously modified. 
     An interlayer  20  may be positioned between the semiconductor substrate  12  and the conductivity type regions  32  and  34  on the back surface of the semiconductor substrate  12 . The interlayer  20  may be positioned on (e.g., contact) the entire back surface of the semiconductor substrate  12 . 
     The interlayer  20  may serve as a passivation layer for passivating the surface of the semiconductor substrate  12 . Alternatively, the interlayer  20  may serve as a dopant control or a diffusion barrier that prevents dopants in the conductivity type regions  32  and  34  from excessively diffusing into the semiconductor substrate  12 . The interlayer  20  may include various materials capable of performing the above-described role. For example, the interlayer  20  may be formed of an oxide layer, a dielectric layer or an insulating layer containing silicon, a nitride oxide layer, a carbon oxide layer, an intrinsic amorphous silicon layer, or the like. For example, when the conductivity type regions  32  and  34  are formed of a polycrystalline semiconductor, the interlayer  20  may be easily manufactured and may be a silicon oxide layer that enables smooth carrier transfer. As another example, when the conductivity type regions  32  and  34  are formed of an amorphous semiconductor, the interlayer  20  may be formed of the intrinsic amorphous silicon layer. 
     A thickness of the interlayer  20  may be less than those of a front passivation layer  24 , an anti-reflection layer  26 , and a back passivation layer  40 . For example, the thickness of the interlayer  20  may be 10 nm or less (e.g., 5 nm or less, more specifically, 2 nm or less, for example, 0.5 nm to 2 nm). This is to fully realize the effect of the interlayer  20 , but the present disclosure is not limited thereto. 
     A semiconductor layer  30  including the conductivity type regions  32  and  34  may be positioned on (e.g., contact) the interlayer  20 . In this embodiment, the conductivity type regions  32  and  34  may include a first conductivity type region  32  having a first conductivity type and a second conductivity type region  34  having a second conductivity type opposite to the first conductivity type. More specifically, the first conductivity type region  32  and the second conductivity type region  34  may be positioned together in the semiconductor layer  30  continuously formed on the interlayer  20 , and may be positioned on the same plane. In addition, a barrier area  36  may be positioned on the same plane between the first conductivity type region  32  and the second conductivity type region  34 . 
     The first and second conductivity type regions  32  and  34 , and the barrier area  36 , or the semiconductor layer  30  may have a different crystal structure from that of the semiconductor substrate  12 . For example, the first and second conductivity type regions  32  and  34 , and the barrier area  36 , or the semiconductor layer  30  may include an amorphous semiconductor, a microcrystalline semiconductor, a polycrystalline semiconductor (e.g., amorphous silicon, microcrystalline silicon, or polycrystalline silicon), or the like, and the first conductivity type region  32  may include the first conductivity type dopant, and the second conductivity type region  34  may include the second conductivity type dopant. The barrier area  36  may be formed of an intrinsic or undoped semiconductor that is not doped with the first and second conductivity type dopants. In this instance, when the first and second conductivity type regions  32  and  34 , and the barrier area  36 , or the semiconductor layer  30  have a polycrystalline semiconductor, they may have a high carrier mobility. Further, when the first and second conductivity type regions  32  and  34 , and the barrier area  36 , or the semiconductor layer  30  have an amorphous semiconductor, they may be formed by a simple process. 
     In this instance, if the base region  12   a  has the second conductivity type, the first conductivity type region  32  having a different conductivity type from the base region  12   a  serves as an emitter region, and the second conductivity type region  34  having the same conductivity type as the base region  12   a  serves as a back surface field region. The barrier area  36  physically separates the first conductivity type region  32  and the second conductivity type region  34 , and thus can prevent a shunt that may occur when they contact each other. 
     In this instance, an area (e.g., a width) of the first conductivity type region  32  may be larger than an area (e.g., a width) of the second conductivity type region  34 . Accordingly, the first conductivity type region  32  serving as the emitter region has a larger area than the second conductivity type region  34  serving as the back surface field region, which may be advantageous for photoelectric conversion. 
     As described above, the first and second conductivity type regions  32  and  34  are formed of a separate layer different from the semiconductor substrate  12  with the interlayer  20  interposed therebetween. As a result, a loss due to recombination can be minimized as compared to the case where a doped region formed by doping a dopant in the semiconductor substrate  12  is used as a conductivity region. The barrier area  36  is formed of an intrinsic or undoped semiconductor, and thus can simplify the process of forming the barrier area  36 . 
     However, the present disclosure is not limited thereto. For example, the interlayer  20  may not be provided. Alternatively, at least one of the first and second conductivity type regions  32  and  34  may be formed as a doped region in which a dopant is doped and formed in a part of the semiconductor substrate  12  to form the part of the semiconductor substrate  12 . The barrier area  36  may not be provided, or the barrier area  36  may include a material other than the semiconductor material. Other modifications may be used. 
     When the first or second conductivity type dopant is p-type, a group III element such as boron (B), aluminum (Al), gallium (Ga), and indium (In) may be used. When the first or second conductivity type dopant is n-type, a group V element such as phosphorus (P), arsenic (As), bismuth (Bi), and antimony (Sb) may be used. For example, one of the first and second conductivity type dopants may be boron (B), and the other may be phosphorus (P). 
     The front passivation layer  24  and the anti-reflection layer  26  may be positioned on (e.g., contact) the front surface of the semiconductor substrate  12 , and the back passivation layer  40  including a contact hole  40   a  may be positioned on (e.g., contact) the conductivity type regions  32  and  34  or the semiconductor layer  30 . The front passivation layer  24  and the anti-reflection layer  26  may be entirely formed on the front surface of the semiconductor substrate  12 , and the back passivation layer  40  may be entirely formed on the semiconductor layer  30  except for the contact hole  40   a . For example, the front passivation layer  24 , the anti-reflection layer  26 , or the back passivation layer  40  may not include a dopant to have excellent insulation properties, passivation characteristics, and the like. 
     For example, the front passivation layer  24 , the anti-reflection layer  26 , or the back passivation layer  40  may have a silicon nitride layer, a silicon nitride layer containing hydrogen, a silicon oxide layer, a silicon oxynitride layer, an aluminum oxide layer, a silicon carbide layer, any one single layer selected from a group consisting of MgF 2 , ZnS, TiO 2 and CeO 2 , or a multi-layered structure in which two or more layers are combined. 
     Further, the first electrode  42  may be electrically connected to the first conductivity type region  32  through a contact hole  46 , and the second electrode  44  may be electrically connected to the second conductivity type region  34  through the contact hole  46 . The detailed material, structure, etc. of the first and second electrodes  42  and  44  are described in detail later. 
     In this embodiment, the first conductivity type region  32  may extend in a first direction (y-axis direction in the drawing), and the plurality of first conductivity type regions  32  may be provided in a second direction (x-axis direction in the drawing) to form a stripe shape. The second conductivity type region  34  may extend in the first direction (y-axis direction in the drawing), and the plurality of second conductivity type regions  34  may be provided in the second direction (x-axis direction in the drawing) to form a stripe shape. The first conductivity type regions  32  and the second conductivity type regions  34  may be alternately positioned in the second direction, and the barrier area  36  mat be positioned between the first conductivity type region  32  and the second conductivity type region  34  to separate them. The first electrode  42  may be formed in a stripe shape correspondingly to the first conductivity type regions  32 , and the second electrode  44  may be formed in a stripe shape correspondingly to the second conductivity type region  34 . The contact hole  46  may be formed so that only parts of the first and second electrodes  42  and  44  are connected to the first conductivity type region  32  and the second conductivity type region  34 , respectively. For example, the plurality of contact holes  46  may be provided corresponding to one first electrode  42  or one second electrode  44 . Alternatively, each contact hole  46  may be formed to have the total length of the first and second electrodes  42  and  44  correspondingly to the first and second electrodes  42  and  44 . Hence, the present disclosure can maximize a contact area between the first and second electrodes  42  and  44  and the first and second conductivity type regions  32  and  34  and improve carrier collection efficiency. Various other modifications can be used. 
     As described above, a width of the first conductivity type region  32  may be greater than a width of the second conductivity type region  34 , and correspondingly, a width of the first electrode  42  (each of the main electrode portion  42   a  and the connection electrode portion  42   b  of the first electrode  42 ) may be greater than a width of the second electrode  44  (each of the main electrode portion  44   a  and the connection electrode portion  44   b  of the second electrode  44 ). However, the present disclosure is not limited. For example, a width of the first electrode  42  (each of the main electrode portion  42   a  and the connection electrode portion  42   b  of the first electrode  42 ) may be equal to or less than a width of the second electrode  44  (each of the main electrode portion  44   a  and the connection electrode portion  44   b  of the second electrode  44 ). 
     When light is incident on the solar cell  10  according to this embodiment, electrons and holes are generated by a photoelectric conversion in a p-n junction formed between the base region  12   a  and the first conductivity type region  32 . The generated holes and electrons pass through the interlayer  20 , move to the first conductivity type region  32  and the second conductivity type region  34 , respectively, and then move to the first and second electrodes  42  and  44 . Hence, electric energy is generated. 
     In the solar cell  10  with a back electrode structure in which the electrodes  42  and  44  are formed on the back surface of the semiconductor substrate  12  and the electrode is not formed on the front surface of the semiconductor substrate  12  as in the present embodiment, a shading loss at the front surface of the semiconductor substrate  12  can be minimized. Hence, efficiency of the solar cell  10  can be improved. However, the present disclosure is not limited thereto. Furthermore, since the first and second conductivity type regions  32  and  34  are formed on the semiconductor substrate  12  with the interlayer  20  interposed therebetween, the first and second conductivity type regions  32  and  34  are formed as separate layers different from the semiconductor substrate  12 . Accordingly, a loss attributable to a recombination can be minimized compared to when a doping region formed by doping a dopant into the semiconductor substrate  12  is used as a conductivity type region. 
     In the present embodiment, the first electrode  42  and the second electrode  44  may be made of a conductive material (e.g., metal). Hereinafter, the lamination structure of the first and/or second electrode(s)  42  and/or  44  is described in detail with reference to the enlarged circle of  FIG. 3 . In the enlarged circle of  FIG. 3 , the first electrode  42  has been enlarged and illustrated, but the second electrode  44  may have the same lamination structure. Accordingly, hereinafter, the first or second conductivity type region  32  or  34  is denoted as the conductivity type regions  32  and  34 , and the first or second electrode  42  or  44  connected to the conductivity type region is denoted as the electrodes  42  and  44 . Furthermore, main electrode portions  42   a  and  44   a  of the first and/or second electrode(s)  42  and/or  44  are denoted as the main electrode portion  42   a , and the connection electrode portions  42   b  and  44   b  of the first and/or second electrode(s)  42  and/or  44  are denoted as the second electrode portion  42   b.    
     The present embodiment has been illustrated and described that an insulating layer  41  is positioned between the conductivity type regions  32  and  34  and the electrodes  42  and  44  and the electrodes  42  and  44 , the insulating layer  41  and the conductivity type regions  32  and  34  form a metal-insulating layer-semiconductor (MIS) structure. 
     More specifically, the insulating layer  41  is positioned between the conductivity type regions  32  and  34  and the electrodes  42  and  44  within the contact hole  46  of the back passivation layer  40 . Hence, a reduction of passivation characteristics, which may occur because the back passivation layer  40  is removed, can be effectively prevented. Furthermore, interface contact characteristics can be improved compared to when the conductivity type regions  32  and  34  and the electrodes  42  and  44  directly contact each other. Furthermore, the insulating layer  41  can prevent a damage to the conductivity type regions  32  and  34  in various processes performed after the contact hole  46  is formed. 
     In the present embodiment, the insulating layer  41  may include refractory metal oxide formed by a combination of a refractory metal and oxygen. For example, the insulating layer  41  may be a refractory metal oxide layer made of refractory metal oxide. An insulating layer formed of silicon oxide has a low reflectance, but the insulating layer  41  has a high refractive index, so a reflectance of a long wavelength can be further improved. Accordingly, light that reaches the back surface of the semiconductor substrate  12  can be effectively reflected. In this case, the insulating layer  41  formed of refractory metal oxide is formed by an atomic layer deposition method not chemical vapor deposition, and may have a high film density and excellent crystallizability. As a result, the reflection of light can be more effectively improved and contact resistance of the electrodes  42  and  44  can be significantly reduced by minimizing the absorption of light. 
     For example, the insulating layer  41  may include titanium oxide (TiOx) (e.g., TiO 2 ) or molybdenum oxide (MoOx) (e.g., MoO 2  or MoO 3 ). For example, the insulating layer  41  may be formed of a titanium oxide layer or a molybdenum oxide layer, and may be formed of a titanium oxide layer, particularly. Titanium oxide or molybdenum oxide has a high reflectance with respect to light of a long wavelength, and can reduce the contact resistance of the electrodes  42  and  44 . Particularly, titanium oxide has such excellent effects. More specifically, if the insulating layer  41  includes titanium oxide having an anatase phase, reflectance improvement and contact resistance reduction effects can be significantly improved because the insulating layer  41  has more excellent crystallizability and a higher refractive index than titanium oxide having other phase. However, the present disclosure is not limited thereto, and the insulating layer  41  may include titanium oxide having other phase (e.g., rutile phase). 
     In this instance, since the conductivity type regions  32  and  34  and the electrodes  42  and  44  are electrically connected with the insulating layer  41  interposed therebetween, the insulating layer  41  may be thinly formed so that electrical connection characteristics between the conductivity type regions  32  and  34  and the electrodes  42  and  44  can be improved. That is, the insulating layer  41  may have a smaller thickness than the back passivation layer  40 , the front passivation layer  24  or the anti-reflection layer  26 , and may have a thickness equal to or less than that of the interlayer  20 . Particularly, the insulating layer  41  may have a smaller thickness than the interlayer  20 . The reason for this is that the insulating layer  41  has only to have a thin thickness to the extent that it does not degrade electrical connection characteristics. 
     For example, the thickness of the insulating layer  41  may be 1 nm or less (e.g., 0.005 nm to 1 nm). If the thickness of the insulating layer  41  exceeds 1 nm, electrical connection characteristics between the conductivity type regions  32  and  34  and the electrodes  42  and  44  may be slightly reduced. Furthermore, if the thickness of the insulating layer  41  is less than 0.005 nm, it may be difficult to entirely form the insulating layer  41  with a uniform thickness, and an effect by the insulating layer  41  may not be sufficient. However, the present disclosure is not limited thereto, and may include various modifications. 
       FIG. 3  illustrates that the insulating layer  41  together with the semiconductor layer  30  exposed by the contact hole  46  is formed entirely and consecutively while covering the surface and side of the back passivation layer  40 , by way of example. In this case, the insulating layer  41  has a very thin thickness, and thus may be formed while having a step, a curve, etc. by the contact hole  46  without any change. However, the present disclosure is not limited thereto. As illustrated in  FIG. 4 , the insulating layer  41  may be patterned when the electrodes  42  and  44  are patterned, and thus may have the side surface that is formed only in a portion, in which the electrodes  42  and  44  are positioned, and is consecutively connected to the side of the electrodes  42  and  44  (particularly, the side surfaces of the main electrode portions  42   a  and  42   b ). Further,  FIG. 3  illustrates that the insulating layer  41  is positioned only at the back surface of the semiconductor substrate  12  and prevents a change in reflection characteristics at the front surface, etc., by way of example. However, the insulating layer  41  may also be positioned at the side surface and/or front surface of the semiconductor substrate  12 . Accordingly, when the electrodes  42  and  44  are patterned, the insulating layer  41  can serve to protect the side surface and/or front surface of the semiconductor substrate  12 . In this instance, the insulating layer  41  may be positioned between the front surface field region  12   b  and the front passivation layer  24 , for example, at the front surface of the semiconductor substrate  12 . However, the present disclosure is not limited thereto. For example, the insulating layer  41  may be positioned between the front passivation layer  24  and the anti-reflection layer  26  or on the anti-reflection layer  26  depending on the forming order of the insulating layer  41 . Alternatively, as illustrated in  FIG. 5 , the insulating layer  41  may not be formed, and thus the first and second electrodes  42  and  44  may contact the first and second conductivity type regions  32  and  34 , respectively. 
     In the present embodiment, the electrodes  42  and  44  include the main electrode portion  42   a  positioned on (e.g., contacting) the conductivity type regions  32  and  34  and the connection electrode portion  42   b  positioned on the main electrode portion  42   a.    
     In this case, the main electrode portion  42   a  may be made of a deposition layer (e.g., sputtering layer) formed by deposition (e.g., sputtering). More specifically, the main electrode portion  42   a  may include a plurality of electrode layers  421 ,  422 ,  423 , and  424 , and each of the plurality of electrode layers  421 ,  422 ,  423 , and  423  may be made of a sputtering layer. In the present embodiment, the main electrode portion  42   a  may include a first electrode layer  421  positioned on the conductivity type regions  32  and  34  (e.g., contacting the insulating layer  41  or the conductivity type regions  32  and  34 ), and may include a second electrode layer  422 , a third electrode layer  423 , and a fourth electrode layer  424  that are sequentially positioned on the first electrode layer  421 . 
     The first electrode layer  421  may serve to prevent metal materials of the second to fourth electrode layers  422 ,  423 , and  424  (particularly, the second electrode layer  422 ) from undesirably reacting with the conductivity type regions  32  and  34 . In this case, the insulating layer  41  may be further positioned between the conductivity type regions  32  and  34  and the first electrode layer  421 . The insulating layer  41  can serve as a barrier to effectively prevent a problem attributable to the diffusion of the metal material. 
     More specifically, various heat treatment processes are performed during various manufacturing processes of the solar cell  10 . For example, after an electrode material layer for forming the electrodes  42  and  44  is formed by a physical vapor deposition (PVD) method such as sputtering, an annealing process is performed to reduce a stress of the electrode material layer and to improve contact characteristics with the conductivity type regions  32  and  34 . In a related art, a problem may occur because the semiconductor material of the conductivity type regions  32  and  34  is diffused into the second electrode layer  422  and the electrode material of the second electrode layer  422  is diffused toward the conductivity type regions  32  and  34  during such a heat treatment process. For example, because an electrode material (particularly, aluminum) of the second electrode layer  422  has a lower melting point than the semiconductor material, an electrode material positioned in the conductivity type regions  32  and  34  may easily flow out due to diffusion. Thus, a spiking phenomenon in which a small hole or a hole is formed in the conductivity type regions  32  and  34  may occur. If the spiking phenomenon occurs in the conductivity type regions  32  and  34  as described above, this means that a defect occurs in the conductivity type regions  32  and  34 . Therefore, the characteristics of the conductivity type regions  32  and  34  may be greatly degraded. In the present embodiment, the above problem can be prevented by disposing the first electrode layer  421  and/or the insulating layer  41  between the conductivity type regions  32  and  34  and the second electrode layer  422 . 
     In this instance, the first electrode layer  421  may include the same refractory metal (e.g., titanium or molybdenum) as a refractory metal contained in the metal oxide of the insulating layer  41 , and the first electrode layer  421  may be made of a refractory metal layer included in the metal oxide of the insulating layer  41 . Particularly, the metal of the first electrode layer  421  and the refractory metal included in the insulating layer  41  may be the same. Thus, since the same refractory metal are included in the first electrode layer  421  and the insulating layer  41 , diffusion attributable to a chemical concentration gradient can be effectively prevented. For example, the insulating layer  41  may include titanium oxide, and the first electrode layer  421  may include titanium. In this case, a stable MIS contact structure can be formed due to low contact resistance and excellent thermal stability. 
     The second electrode layer  422  positioned on (e.g., contacting) the first electrode layer  421  may serve to improve electrical characteristics because it has a low resistance (e.g., lower resistance than the first electrode layer  421 ). As described above, the second electrode layer  422  may include aluminum (Al), copper (Cu), silver (Ag) or gold (Au), etc. Particularly, the second electrode layer  422  may include aluminum. If the second electrode layer  422  includes aluminum, the side of the second electrode layer  422  and the main electrode portion  42   a  including the second electrode layer  422  may have a cross section according to a desired pattern. On the other hand, if the second electrode layer  422  includes copper, an etchant used when patterning the main electrode portion  42   a  strongly etches the side of the second electrode layer  422  made of copper at a fast speed, thereby generating an under-cut in the second electrode layer  422 . Hence, at least part of the side of the second electrode layer  422  is positioned more inside than the first, third and fourth electrode layers  421 ,  423 , and  424 , and thus it may be difficult to stably pattern the main electrode portion  42   a  in a desired shape. 
     The third electrode layer  423  positioned on (e.g., contacting) the second electrode layer  422  may serve as a barrier to prevent the metal material of the second electrode layer  422  from being diffused into the fourth electrode layer  424 . A resistance may increase due to an alloy formed by a reaction between the metal material of the second electrode layer  422  and the metal material of the fourth electrode layer  424 , and the third electrode layer  423  can prevent this. The third electrode layer  423  may include the same material (i.e., refractory metal, for example, titanium, molybdenum, or tungsten) as the first electrode layer  421 . 
     The fourth electrode layer  424  positioned on (e.g., contacting) the third electrode layer  423  may include tin (Sn) or a nickel-vanadium alloy (NiV). Tin or nickel-vanadium alloy has a very excellent adhesion characteristic with the connection electrode portion  42   b . More specifically, if the connection electrode portion  42   b  includes tin, adhesion characteristic between tin of the connection electrode portion  42   b  and nickel of the nickel-vanadium alloy is very excellent. Further, the nickel-vanadium alloy has a very high melting point of about 1000° C. or more, and thus has a higher melting point than the first to third electrode layers  421 ,  422 , and  423 . Hence, the nickel-vanadium alloy is not modified during an attaching process with the wiring portion  140  or a process of manufacturing the solar cell  10 , and can sufficiently serve as a capping layer for protecting the first to third electrode layers  421 ,  422 , and  423 . However, the present disclosure is not limited thereto, and the fourth electrode layer  424  may be made of various conductive materials (e.g., various metals). 
     A thickness of the first electrode layer  421  may be less than a thickness of each of the second electrode layer  422  and the fourth electrode layer  424 . More specifically, the thickness of the first electrode layer  421  may be 50 nm or less (e.g., 15 nm or less, for example, 2 nm to 15 nm). The reason for this is that the first electrode layer  421  can sufficiently implement the above-described effect even with a thin thickness. 
     The second electrode layer  422  may have a greater thickness than the first electrode layer  421 , the third electrode layer  423  and/or the fourth electrode layer  424 , and may have a thickness of 50 nm to 400 nm, for example. For example, the thickness of the second electrode layer  422  may be 100 nm to 400 nm (more specifically, 100 nm to 300 nm). If the thickness of the second electrode layer  422  is less than 50 nm, the second electrode layer  422  may not play the roles of a barrier layer and a reflection electrode layer. If the thickness of the second electrode layer  422  exceeds 400 nm, reflection characteristics, etc. are not greatly improved, and manufacturing cost may increase. If the thickness of the second electrode layer  422  is 100 nm to 300 nm, the resistance can be further reduced, and peeling-off attributable to a thermal stress can be effectively prevented. 
     The third electrode layer  423  may have a smaller thickness than each of the second electrode layer  422  and the fourth electrode layer  424 . For example, the thickness of the third electrode layer  423  may be 50 nm or less. If the thickness of the third electrode layer  423  exceeds 50 nm, the resistance may relatively increase. In this case, the thickness of the third electrode layer  423  may be 5 nm to 50 nm. If the thickness of the third electrode layer  423  is less than 5 nm, the third electrode layer  423  may not be uniformly formed between the second electrode layer  422  and the fourth electrode layer  424 . Hence, an effect in that a reaction between the third electrode layer  423  and the second electrode layer  422  and the fourth electrode layer  424  is prevented may not be sufficient. Alternatively, the third electrode layer  423  may have the same or similar thickness as the first electrode layer  421  or may have a greater thickness than the first electrode layer  421 . However, the present disclosure is not limited thereto, and the third electrode layer  423  may have a smaller thickness than the first electrode layer  421 . 
     The fourth electrode layer  424  may have a thickness of a nano level, for example, a thickness of 50 nm to 300 nm. If the thickness of the fourth electrode layer  424  is less than 50 nm, adhesion characteristic between the fourth electrode layer  424  and the connection electrode portion  42   b  may be degraded. If the thickness of the fourth electrode layer  424  exceeds 300 nm, the manufacturing cost may increase. 
     In the present embodiment, the first electrode layer  421 , the second electrode layer  422 , the third electrode layer  423  and the fourth electrode layer  424  may be formed to contact each other. Accordingly, the characteristics of the main electrode portion  42   a  can be improved, and the lamination structure of the main electrode portion  42   a  can be simplified. For example, in the present embodiment, the main electrode portion  42   a  may have a four-layer lamination structure including the first to fourth electrode layers  421 ,  422 ,  423 , and  424 . Accordingly, the lamination structure of the main electrode portion  42   a  can be simplified to the maximum. However, the present disclosure is not limited thereto, and the main electrode portion  42   a  may have a separate layer between the first to fourth electrode layers  421 ,  422 ,  423 , and  424  or thereon. Furthermore, the main electrode portion  42   a  may not include at least one of the first to fourth electrode layers  421 ,  422 ,  423 , and  424 . 
     In the present embodiment, the main electrode portion  42   a  may be formed by forming a plurality of electrode material layers including the first to fourth electrode layers  421 ,  422 ,  423 , and  424  by sputtering and then patterning the plurality of electrode material layers. More specifically, after electrode material layers corresponding to the first to fourth electrode layers  421 ,  422 ,  423 , and  424  are entirely sequentially formed to fill the contact hole  46  of the back passivation layer  40 , the main electrode portion  42   a  may be formed by patterning the electrode material layers. Since the corresponding materials are stacked in a thickness direction of the solar cell  10  by the sputtering as described above, the corresponding materials are stacked so that the first electrode layer  421  has a uniform thickness in the entire portion, the second electrode layer  422  has a uniform thickness in the entire portion, the third electrode layer  423  has a uniform thickness in the entire portion, and the fourth electrode layer  424  has a uniform thickness in the entire portion. Here, the uniform thickness may indicate a thickness (e.g., a thickness having a difference within 10%) which may be determined to be uniform when considering a process error, etc. 
     If each of the first to fourth electrode layers  421 ,  422 ,  423 , and  424  is formed by sputtering as described above, it may be formed of a single metal layer (all the remainders other than inevitable impurities are single metal) including a single metal which may be included in each of the electrode layers  421 ,  422 ,  423 , and  424 . Accordingly, each of the first to fourth electrode layers  421 ,  422 ,  423 , and  424  may include a single metal of 99.9 wt % or more (more specifically, 99.99 wt % or more) which may be included in each of the electrode layers  421 ,  422 ,  423 , and  424 . However, the present disclosure is not limited thereto, and content of the single metal of each of the first to fourth electrode layers  421 ,  422 ,  423 , and  424  may be changed depending on a manufacturing method, process conditions, etc. of the first to fourth electrode layers  421 ,  422 ,  423 , and  424 . Further, the material, thickness, lamination structure, etc. of each of the first to fourth electrode layers  421 ,  422 ,  423 , and  424  may also be variously changed. 
     In the present embodiment, the connection electrode portion  42   b  formed of a printing layer by printing may be positioned on the main electrode portion  42   a  formed of the sputtering layer. For example, the connection electrode portion  42   b  may contact the main electrode portion  42   a  (more specifically, the fourth electrode layer  424 ). In the present embodiment, a density of the connection electrode portion  42   b  that forms the outermost layer of the electrodes  42  and  44  and is formed of the printing layer is less than a density of the main electrode portion  42   a  formed of the sputtering layer. 
     In the present embodiment, the connection electrode portion  42   b  may serve as an electrode for collecting and transmitting electric current with a low electrical resistance, and as a solder paste for adhesion to the wiring member  142  by including a solder material and an adhesive material. That is, the connection electrode portion  42   b  may be a solder paste electrode that serves both as an electrode for improving electrical characteristics and as a solder paste for adhesion to the wiring member  142 . Hence, the present embodiment does not require a separate solder paste layer for electrical connection (for example, high temperature firing paste, e.g., high temperature firing paste soldered by heat treatment at a temperature exceeding 280° C.). Thus, the wiring member  142  may be directly connected to the connection electrode portion  42   b  (particularly, a cover layer  428 ) or directly positioned on an adhesive layer LSP positioned at (e.g., contacting) the connection electrode portion  42   b  (particularly, a cover layer  428 ), and may be connected to the electrodes  42  and  44 . This is described in detail later with reference to  FIGS. 7 and 8 . Here, the adhesive layer LSP may be formed on a plurality of insulating members IP and the plurality of electrodes  42  and  44  along the extension direction of the wiring member  142  correspondingly to the wiring member  142  so that the adhesive layer LSP is attached or temporarily fixed to the wiring member  142 . The adhesive layer LSP may be distinguished from the connection electrode portion  42   b  formed corresponding to each of the electrodes  42  and  44  or a related art solder paste layer. The adhesive layer LSP may be formed of a low temperature solder paste. For example, the adhesive layer LSP may have a lower melting temperature than the connection electrode portion  42   b  or the related art solder paste layer. 
     Hence, in the present embodiment, the connection electrode portion  42   b  may be formed of a paste (metal material paste) including a first metal, a solder material including a second metal different from the first metal, and an adhesive material. More specifically, the connection electrode portion  42   b  may include a particle connection layer  426  formed by connecting (e.g., contacting) a plurality of particles  426   a  including the first metal to each other, and a cover layer  428  including the second metal and formed while covering at least an outer surface of the particle connection layer  426 . The adhesive material or a part thereof may be removed in the heat treatment process, etc., and the adhesive material or a part of the material constituting the same may remain or may not remain in the connection electrode portion  42   b  in the final structure. In addition, other organic material, etc. may further remain. Whether the adhesive material or the material constituting the same remains may be determined by various component analysis methods, micrographs, and the like. 
     Here, the first metal may be for reducing the resistance of the connection electrode portion  42   b  and the electrodes  42  and  44  including the same, the second metal or the solder material may be for soldering with the wiring portion  140 , and the adhesive material may serve to improve adhesion between the connection electrode portion  42   b  and the wiring portion  140 . The cover layer  428  or the second metal constituting the same may serve to prevent oxidation of the metal constituting the particle connection layer  426 , and to assist in the connection of the particles  426   a  in the particle connection layer  426 , etc. 
     The first metal included in the connection electrode portion  42   b  may be the material of the respective electrode layers  421 ,  422 ,  423  and  424  of the main electrode portion  42   a  or a metal having a resistivity equal to or less than a resistivity of the second metal. In particular, the first metal may be the material of the respective electrode layers  421 ,  422 ,  423  and  424  of the main electrode portion  42   a  or a metal having a resistivity less than a resistivity of the second metal. For example, copper, silver, aluminum, gold, etc. may be used as the first metal, but titanium (Ti) having a high resistivity may not be used. In particular, the first metal may be copper which has a very low resistivity and is inexpensive. 
     The solder material including the second metal may be a material that enables soldering. For example, the second metal may be tin (Sn), and the solder material may consist of only the second metal or may be an alloy further including other metal. For example, soldering characteristics may be further improved by using a tin-silver-copper (Sn—Ag—Cu, SAC)-based alloy as a solder material. In this case, the solder material may include tin as a main material (a material of 50 vol % or more), and silver and copper may be included in an amount less than that of tin. Since the second metal includes the same material as the solder metal (e.g., tin) included in the wiring portion  140  as described above, contact characteristics and adhesion characteristics with the wiring portion  140  can be greatly improved. The second metal or the solder material has a lower melting point than that of the first metal, and thus may be easily melted in the heat treatment process and then aggregated. Thus, the cover layer  428  can be stably formed on the outer surface of the connection electrode portion  42   b  and serve to physically and electrically connect the particles  426   a  including the first metal. Since the second metal including tin has a lower ionization tendency or lower metal reactivity than the first metal, it may also serve to prevent oxidation of the first metal or the particle connection layer  426 . 
     The adhesive material may include an organic material, an inorganic material, etc. as a material capable of improving soldering characteristics, and may have non-conductive properties. For example, the adhesive material may be a material including both an organic material and an inorganic material, for example, a flux including carbon, oxide, rosin, etc. The flux may include carbon, oxide, rosin, etc., and serve to improve adhesion characteristics between the connection electrode portion  42   b  and the wiring portion  140  during soldering. In addition, the flux may include an additive for effective dispersion. However, the present disclosure is not limited thereto, and various materials capable of improving the adhesion characteristics of the wiring portion  140  may be used as the adhesive material. 
     The paste including the first metal, the solder material including the second metal, and the adhesive material will be described in more detail later in the description of the method for manufacturing the solar cell panel  100 . 
     The connection electrode portion  42   b  may form a part of an electrode using a solder paste that has been used for the attachment between the electrodes  42  and  44  and the wiring member  142  in the related art. The connection electrode portion  42   b  may be considered as a solder paste in which the first metal for lowering a resistance is added to a material constituting the related art solder paste. Alternatively, the connection electrode portion  42   b  may be considered as an electrode portion to which an adhesive material is added to an existing electrode portion together with a solder material. Hence, the connection electrode portion  42   b  may be considered as a solder paste electrode that serves as an electrode having excellent electrical characteristics and as a solder paste having an excellent adhesive force to the wiring portion  140 . In addition, an adhesive force with the main electrode portion  42   a  can be greatly improved by the adhesive material. 
     The particle connection layer  426  includes the plurality of particles  426   a  including the first metal having a low resistivity, and may serve to reduce the resistance of the electrodes  42  and  44 . The particle connection layer  426  may be a layer formed by a plurality of particles which is hardened at a lower melting point than a melting point of the first metal and then is aggregated and connected (e.g., cross-linked) in the thickness direction and/or plane direction of the electrodes  42  and  44 . For example, the plurality of particles of the particle connection layer  426  may be physically and electrically connected by a direct contact or may be physically and electrically connected through the cover layer  428  or remaining portions  428   a  and  428   b , or a binder that is positioned between the plurality of particles or over the plurality of particles. The particle connection layer  426  is a layer interconnected by hardening. Accordingly, in the heat treatment for forming the particle connection layer  426 , the first metal does not melt at a melting point or more and is not sintered, and thus there is no necking phenomenon in which a part of the particles is deformed and is combined. Hence, a plurality of particles  426   b  having a substantially spherical shape remain in the state in which they have contacted and connected each other, and thus a shape of a curved surface having uneven curves along partial surfaces of the plurality of particles  426   a  is formed on the outer surface of the particle connection layer  426  (i.e., a surface not contacting the main electrode portion  42   a  or a surface covered by the cover layer  428 ). For example, the outer surface of the particle connection layer  426  may have a shape of a curved surface having a plurality of concave parts corresponding to the portions of the substantially spherical shape. 
     For example, the plurality of particles  426   a  may have an average particle diameter of 2 um or more (for example, 2 μm to 15 μm). It may have a difficulty in forming the particles  426   a  having the average particle diameter less than 2 μm. If the average particle diameter of the particles  426   a  exceeds 15 μm, it may be difficult to form the electrodes  42  and  44  to a desired thin width. Alternatively, the average particle diameter of the plurality of particles  426   a  may be greater than a thickness of the respective electrode layers  421 ,  422 ,  423  and  424  constituting the main electrode portion  42   a . For example, the average particle diameter of the plurality of particles  426   a  may be equal to or greater than (particularly, may be greater than) a total thickness of the main electrode portion  42   a . When the plurality of particles  426   a  have the average particle diameter of a predetermined level as described above, the resistance of the connection electrode portion  42   b  can be efficiently reduced. However, the present disclosure is not limited thereto. 
     The cover layer  428  includes the second metal and is formed to cover at least the outer surface of the particle connection layer  426 . If the second metal has a lower melting point than the first metal, the particles can easily melt at a relatively low temperature and can be easily aggregated. Thus, the second metal may flow out between the plurality of particles  426   a  including the first metal in a heat treatment process and may be aggregated at the outer surface of the particle connection layer  426  to form a layer shape, thereby forming the cover layer  428 . The cover layer  428  may be formed to entirely and consecutively cover the outer surface of the particle connection layer  426 . Hence, the cover layer  428  can effectively serve to prevent a change in characteristics (e.g., oxidization), etc. of the particle connection layer  426  and to protect the particle connection layer  426 . Furthermore, if the second metal forming the cover layer  428  is includes a material included in a solder material, contact characteristics with the wiring portion  140 , etc. can be improved. 
     Here, the cover layer  428  may be formed to fill a space between the plurality of particles  426   a  formed of the first metal. Furthermore, the remaining portions  428   a  and  428   b  including the same second metal as the cover layer  428  may be spaced apart from the cover layer  428  and may be further positioned between the plurality of particles  426   a  or at a boundary surface adjacent to the main electrode portion  42   a . The remaining portions  428   a  and  428   b  may include the first remaining portion  428   a  that is spaced apart from the cover layer  428  and is positioned between the plurality of particles  426   a , and the second remaining portion  428   b  that is partially formed at the boundary surface adjacent to the main electrode portion  42   a  and has a smaller thickness than the cover layer  428 . 
     In the present embodiment, in the connection electrode portion  42   b , a volume ratio of the first metal may be equal to or less than a volume ratio of the second metal. For example, in the connection electrode portion  42   b , the volume ratio of the first metal may be less than the volume ratio of the second metal. Hence, a sufficient amount of the second metal involved in soldering can be included in the connection electrode portion  42   b  to improve adhesion characteristics with the wiring portion  140 . However, the present disclosure is not limited thereto. For example, in the connection electrode portion  42   b , the volume ratio of the first metal may be greater than the volume ratio of the second metal. 
     A thickness of the particle connection layer  426  may be less than a thickness of the cover layer  428 , or may be equal to the thickness of the cover layer  428 , or may be greater than the thickness of the cover layer  428 . For example, since a larger volume ratio of the second metal is included, the thickness of the cover layer  428  may be equal to or greater than the thickness of the particle connection layer  426 . The outer surface of the particle connection layer  426  may be formed as a curved surface having uneven curves by the shape of the plurality of particles. In this instance, a second thickness T 2  of the cover layer  428  may be greater than a surface roughness R 1  of the outer surface of the particle connection layer  426  (i.e., a distance between a most protruding portion and a least protruding portion protruding from the outer surface of the particle connection layer  426  to the outside). Thus, the cover layer  428  can stably cover the particle connection layer  426 . Furthermore, the outer surface of the cover layer  428  may have a smaller surface roughness than the outer surface of the particle connection layer  426 . Hence, adhesive stability with the wiring portion  140  can be further improved by reducing the surface roughness of the connection electrode portion  42   b  at a surface to which the wiring portion  140  is attached. 
     As described above, the connection electrode portion  42   b  is comprised of a printing layer formed by printing, and the particle connection layer  426  may also be formed to have a sufficient thickness. Thus, resistance can be effectively reduced by the low resistivity of the first metal. 
     When viewed in the second direction (x-axis direction in the drawing) intersecting the first direction (y-axis direction in the drawing) in which the electrodes  42  and  44  extend, a width (e.g., maximum width) of the connection electrode portion  42   b  may be equal to or less than a width (e.g., maximum width) of the main electrode portion  42   a . However, the present disclosure is not limited thereto. When viewed in the second direction, a width (e.g., maximum width) of the connection electrode portion  42   b  may be greater than a width (e.g., maximum width) of the main electrode portion  42   a.    
     For example, a ratio of the width (e.g., maximum width) of the connection electrode portion  42   b  to the width (e.g., maximum width) of the main electrode portion  42   a  may be equal to or greater than 0.5 (e.g., 0.8 to 1.5). If the ratio is less than 0.5, a resistance reduction effect resulting from the connection electrode portion  42   b  may not be sufficient. If the ratio is equal to or greater than 0.8, a resistance reduction effect resulting from the connection electrode portion  42   b  may be sufficiently implemented. If the ratio exceeds 1.5, problems such as a reduction in structural stability and insulation properties may occur by the connection electrode portion  42   b  formed in addition to the main electrode portion  42   a . However, the present disclosure is not limited thereto. 
     When viewed in the second direction, the electrodes  42  and  44  may be formed to have a greater width than the contact hole  46 . This is to reduce a resistance of the electrodes  42  and  44  by sufficiently securing the widths of the first and second electrodes  42  and  44  (i.e., the greatest width of widths of the portions constituting the electrodes  42  and  44 ). Accordingly, the electrodes  42  and  44  (particularly, the first electrode layer  421 ) may be formed over the insulating layer  41  positioned inside (i.e., on the bottom surface and the side) the contact hole  46  and over the insulating layer  41  positioned on the back passivation layer  40  adjacent to the contact hole  46 . If the insulating layer  41  is not included, the electrodes  42  and  44  (particularly, the first electrode layer  421 ) may be formed on the conductivity type regions  32  and  34  exposed through the inside of the contact hole  46  and on the side and the surface of the back passivation layer  40  adjacent to the contact hole  46 . 
     The connection electrode portion  42   b  may have a greater thickness than the main electrode portion  42   a . The connection electrode portion  42   b  is a layer for reducing resistance of the electrodes  42  and  44  and may be formed to have a sufficient thickness in order to effectively reduce the resistance. For example, a ratio of the thickness (e.g., average thickness) of the connection electrode portion  42   b  to the thickness (e.g., average thickness) of the main electrode portion  42   a  may be 10 times or more. For example, a ratio of the thickness of the connection electrode portion  42   b  to the thickness of the main electrode portion  42   a  may be  10  times to  250  times. If the ratio is 10 times or more, a resistance reduction effect by the thickness of the connection electrode portion  42   b  can be maximized. If the ratio exceeds  250  times, there may be a problem in that the structural stability of the electrodes  42  and  44  is reduced. Alternatively, the thickness of the main electrode portion  42   a  may be 1 μm or less (e.g., 600 nm or less), and the thickness of the connection electrode portion  42   b  may be 5 μm or more (e.g., 10 μm to 100 μm, more specifically, 10 μm to 50 μm). The present disclosure can simplify the manufacturing process while maximizing the effect by the main electrode portion  42   a  and the connection electrode portion  42   b  within the range and can prevent a reduction in the structural stability of the electrodes  42  and  44 . 
     As described above, in the present embodiment, the connection electrode portion  42   b  may be formed as a part of the electrode by coating, drying and curing the paste (e.g., solder paste) including both the solder material including the first metal and the second metal and the adhesive material on the main electrode portion  42   a . Hence, the present disclosure can effectively reduce the resistance of the connection electrode portion  42   b  and the electrodes  42  and  44  including the connection electrode portion  42   b  by forming the connection electrode portion  42   b  to a sufficient thickness while simplifying the manufacturing process. A method of manufacturing the connection electrode portion  42   b  using the paste including the first metal, the solder material, and the adhesive material is described in more detail later with reference to  FIGS. 9 a  to 9 f    and  10 . 
     On the contrary, when an electrode layer including a first metal and an electrode layer that is formed on the electrode layer and includes a second metal for connection with a wiring portion are separately formed, the electrode layers need to be sequentially formed inside a vacuum equipment in order to prevent the oxidization of the first metal. Accordingly, a process becomes complicated, and there is a difficulty in forming the electrode layers (particularly, the electrode layer including the first metal) to a sufficient thickness. On the other hand, in the present embodiment, a process can be simplified and the connection electrode portion  42   b  can be formed to a sufficient thickness by applying a printing process using a paste including both a first metal and a second metal. Particularly, the connection electrode portion  42   b  including the particle connection layer  426  formed by connecting the plurality of particles including the first metal may be formed by heat treatment having a relatively low temperature (e.g., 450° C. or less). 
     There is no problem of degradation in the characteristics of the conductivity type regions  32  and  34  or a damage to the conductivity type regions  32  and  34  in a process of forming the electrodes  42  and  44 . 
     Unlike the present embodiment, if an electrode is comprised of only a printing layer, the electrode is comprised of only a layer with low density, and thus contact characteristics between the electrode and the conductivity type regions  32  and  34  may not be excellent and the electrode may be easily peeled off from the conductivity type regions  32  and  34 . Furthermore, in order to connect the electrode comprised of the printing layer to the conductivity type regions  32  and  34 , heat treatment at a high temperature (e.g., 700° C. or more) is necessary since a firing or sintering process is necessary. Accordingly, the characteristics of the conductivity type regions  32  and  34  may be changed because a dopant included in the conductivity type regions  32  and  34  is undesirably diffused or activated during the heat treatment process, and there may be a problem, such as that the conductivity type regions  32  and  34  is damaged due to a high temperature. 
     Furthermore, unlike the present embodiment, if an electrode is comprised of only a sputtering layer, it may be difficult to form the electrode to a sufficient thickness (e.g., exceeding 1 μm). If a process time greatly increases in order to form the electrode to a sufficient thickness, there is a problem in that the characteristics of the conductivity type regions  32  and  34  are degraded when the electrode is formed. Hence, there is a limit to a reduction in a resistance of the electrode. 
     Furthermore, unlike the present embodiment, if an electrode includes a plating layer, the plating layer needs to be formed through plating after a sputtering layer, a printing layer, etc. are formed. In this case, a density of the plating layer is similar to a density of the sputtering layer and is higher than a density of the printing layer. Thus, the density of the plating layer positioned at the outside is equal to or higher than the densities of the sputtering layer, the printing layer, etc. positioned at the inside. If the plating layer is included as in the related art, the plating layer is also formed on the side of the sputtering layer, the printing layer, etc. and on the insulating layer around them. If a defect, such as a pin hole or a scratch, is present in the back passivation layer  40  or the insulating layer  41 , an unwanted portion may be plated because plating is also performed on the corresponding portion. Since a plating solution used in the plating process is acid or alkali, the back passivation layer  40  or the insulating layer  41  may be damaged or the characteristics of the back passivation layer  40  or the insulating layer  41  may be degraded. Hence, passivation characteristics may be degraded, and an open-circuit voltage of the solar cell  10  may be reduced because a leakage current occurs. When various forms of electrode portions are mixed and used as in the related art as described above, a density of an electrode portion forming the outermost layer is equal to or higher than a density of an electrode portion underlying the electrode portion forming the outermost layer as described above. Hence, the related art is different from the present embodiment in which a printing layer with the low density is positioned at the outside and a sputtering layer with the high density is positioned at the inside. 
     For another example, if both a printing layer and a plating layer are formed, the stability of an electrode may not be good and it may be difficult to stably attach the wiring portion  140  to the electrode, because a height of the electrode is excessively high. Particularly, as in the present embodiment, in a structure in which both the electrodes  42  and  44  are positioned on one surface (i.e., the back surface) of the semiconductor substrate  12 , and the wiring portion  140  is extended in a direction intersecting the electrodes  42  and  44  and needs to be connected to only a desired one of the electrodes  42  and  44  and should not be connected to the other of the electrodes  42  and  44 , it may be difficult to stably attach the wiring portion  140  to an electrode in which both a printing layer and a plating layer are formed. For reference, it is technically less likely that the sputtering layer is formed on the plating layer, which is not advantageous in terms of the process. 
     In the present embodiment, as described above, the connection electrode portion  42   b  may be formed as the printing layer and may be formed to have a desired shape when the connection electrode portion  42   b  is formed. The printing layer has a pattern and may be formed only in a desired portion. Accordingly, the present embodiment can fundamentally prevent problems such as a leakage current, deterioration in passivation characteristics, and a reduction in an open-circuit voltage that may occur when the electrode is formed in an undesired portion due to the printing layer. 
     In this instance, an intermetallic compound (IMC) layer  420 , in which a metal included in the main electrode portion  42   a  (particularly, the fourth electrode layer  424 ) and the second metal are mixed, may be positioned between the main electrode portion  42   a  and the connection electrode portion  42   b . For example, the intermetallic compound layer  420  may be a compound layer in which a nickel-vanadium (Ni—V) alloy and tin (Sn) are mixed. The intermetallic compound layer  420  may be formed in the heat treatment process performed after the printing layer for forming the connection electrode portion  42   b  is formed, and may serve to improve adhesion characteristics between the main electrode portion  42   a  and the connection electrode portion  42   b . For example, in the present embodiment, a sufficient amount of the second metal is contained in the connection electrode portion  42   b , and the intermetallic compound layer  420  can be stably formed. Here, a thickness of the intermetallic compound layer  420  may be 1 nm or more (for example, 20 nm to 500 nm). The present embodiment may not change other characteristics while maximizing an effect of the intermetallic compound layer  420  within the thickness. 
     A laminated structure, a plane shape, etc. of the main electrode portion  42   a  and the connection electrode portion  42   b  are described later after the wiring portion  140  is described. 
     In the present embodiment, the first and second electrodes  42  and  44  each may include the main electrode portions  42   a  and  44   a  and the connection electrode portions  42   b  and  44   b . The first and second electrodes  42  and  44  each may further include the intermetallic compound layer  420  between the main electrode portions  42   a  and  44   a  and the connection electrode portions  42   b  and  44   b . The manufacturing process can be simplified by simultaneously forming the main electrode portions  42   a  and  44   a  and the connection electrode portions  42   b  and  44   b  of the first and second electrodes  42  and  44  in the same process. However, the present disclosure is not limited thereto. For example, one of the first and second electrodes  42  and  44  may have the above-described structure, and the other may have a different structure. Other modifications can be used. 
     100 or more portions (e.g., the first and second electrodes  42  and  44 ) of the first and second electrodes  42  and  44  including the connection electrode portions  42   b  and  44   b  extended in the first direction (the y-axis direction in the drawing) and including copper and tin as described above (more specifically, the connection electrode portions  42   b  and  44   b  each including the particle connection layer  426  including copper and the cover layer  428  covering the particle connection layer  426 ) may be positioned on one surface of the semiconductor substrate  10 . Accordingly, carriers can be stably collected and transmitted because a carrier moving distance can be reduced. In this case, as described above, the thickness of the connection electrode portions  42   b  and  44   b  extended in one direction and including copper and tin (more specifically, the connection electrode portions  42   b  and  44   b  including the particle connection layer  426  including copper and the cover layer  428  covering the particle connection layer  426 ) or the thickness of the first, second electrodes  42  and  44  including the connection electrode portions  42   b  and  44   b  may be 5 μm or more (for example, 10 μm or more). However, the present disclosure is not limited thereto. 
     The solar cell  10  is electrically connected to other solar cell or the outside by the wiring portion  140  including the wiring member  142 . Hereinafter, a connection structure of the solar cell  10  and the wiring portion  140  is described in more detail with reference to  FIGS. 6 and 7 . 
       FIG. 6  is a rear plan view schematically illustrating two solar cells  10 , an insulating member IP, and a wiring portion  140  included in the solar cell panel  100  illustrated in  FIG. 1 .  FIG. 7  is a partial cross-sectional view taken along line VII-VII of  FIG. 6 .  FIGS. 6 and 7  schematically illustrate the structure of the electrodes  42  and  44  focusing on the connection structure of the electrodes  42  and  44  and the wiring portion  140  in order to describe the connection structure of the electrodes  42  and  44  of the solar cell  10  and the wiring portion  140 , by way of example. Thus, the present embodiment is not limited to the number, the shape, etc. of the electrodes  42  and  44  and the wiring member  142  illustrated in  FIGS. 6 and 7 . 
     Referring to  FIGS. 6 and 7 , in the present embodiment, in a plurality of overlap portions of the electrodes  42  and  44  and the wiring portions  140 , in an overlap portion in which the electrodes  42  and  44  and the wiring portions  140  need to be electrically connected to each other, the electrodes  42  and  44  (the connection electrode portions  42   b  and  44   b ) and the wiring portions  140  contact each other and are connected with an adhesive layer LSP interposed therebetween. Further, in an overlap portion in which the electrodes  42  and  44  and the wiring portions  140  do not need to be electrically connected to each other, an insulating member IP is positioned between the electrodes  42  and  44  and the wiring portions  140 . Hence, a separately positioned connection member (e.g., the related art solder paste layer) may be omitted between the electrodes  42  and  44  and the wiring portions  140 . 
     More specifically, the first electrode  42  of the first solar cell  10   a  and the second electrode  44  of the second solar cell  10   b  adjacent to it may be connected by the plurality of wiring members  142  and the connecting wiring member  144 . 
     In the present embodiment, the electrodes  42  and  44  may include a plurality of first and second electrodes  42  and  44  that extend in the first direction (y-axis direction in the drawing) and are alternately positioned in a direction (x-axis direction in the drawing) intersecting the first direction. The wiring member  142  may include a first wiring member  142   a  extending in the second direction and electrically connected to the first electrode  42  and a second wiring member  142   b  extending in the second direction and electrically connected to the second electrode  44 . A plurality of first wiring members  142   a  may be provided, and a plurality of second wiring members  142   b  may be provided, and the first wiring members  142   a  and the second wiring members  142   b  may be alternately positioned in the first direction. Then, the plurality of first and second wiring members  142   a  and  142   b  may be connected to the first and second electrodes  42  and  44  at uniform intervals to effectively transfer the carriers. 
     In this instance, the first wiring member  142   a  is electrically connected to the first electrode  42  included in each solar cell  10  with the adhesive layer LSP disposed therebetween, and the second wiring member  142   b  directly contact the second electrode  44  included in each solar cell  10  and is electrically connected to the second electrode  44  with the adhesive layer LSP disposed therebetween. In addition, the first wiring member  142   a  and the second electrode  44  may be insulated from each other by the insulating member IP, and the second wiring member  142   b  and the first electrode  42  may be insulated from each other by the insulating member IP. 
     The insulating member IP may be positioned in the overlap portion of the first wiring member  142   a  and the second electrode  44 , which should not be at least electrically connected to each other, and may electrically insulate them. Similarly, the insulating member IP may be positioned in the overlap portion of the second wiring member  142   b  and the first electrode  42  which should not be at least electrically connected to each other, and may electrically insulate them. The insulating member IP may include various insulating materials. For example, the insulating member IP may include silicone resin, epoxy resin, urethane resin, acrylic resin, polyimide, polyethylene, or the like. 
     In the present embodiment, the connection electrode portion  42   b  may be formed on the main electrode portion  42   a  in various plane shapes. 
     For example, as illustrated in the enlarged view of  FIG. 6 , the main electrode portions  42   a  and  44   a  may continuously elongate along the first direction (y-axis direction in the drawing), and the connection electrode portions  42   b  and  44   b  may be partially formed on a part of the main electrode portions  42   a  and  44   a  in the first direction and may not be formed on other part. In this instance, the connection electrode portions  42   b  and  44   b  may be formed to include partially or entirely an overlap portion of the electrodes  42  and  44  and the wiring portion  140  that have to be electrically connected to each other. For example, the plurality of connection electrode portions  42   b  and  44   b  may be provided to be spaced apart from each other at a predetermined distance in the first direction. 
     More specifically, as illustrated in  FIG. 7 , the main electrode portion  42   a  of the first electrode  42  may continuously elongate along the first direction, and the plurality of insulating members IP may be positioned on the main electrode portion  42   a  to be spaced apart from each other in the first direction. The plurality of insulating members IP may be positioned in an overlap portion of the insulating member IP and the second wiring member  142   b . Further, the connection electrode portion  42   b  may be positioned on the main electrode portion  42   a  to include a portion, in which the plurality of insulating members IP are not positioned, i.e., a portion overlapping at least the first wiring member  142   a . Here, the connection electrode portion  42   b  in the first direction may be the same as a portion overlapping the first wiring member  142   a  or may have a greater length than the portion. In particular, the connection electrode portion  42   b  in the first direction may have a greater length than a portion overlapping the first wiring member  142   a . However, the present disclosure is not limited thereto. For example, the connection electrode portion  42   b  in the first direction may have a smaller length than a portion overlapping the first wiring member  142   a . In this instance, the connection electrode portion  42   b  may be positioned to be spaced apart from the plurality of insulating members IP in the first direction. Hence, the present disclosure can simplify the manufacturing process of the connection electrode portion  42   b  and reduce the material cost by reducing an area of the connection electrode portion  42   b.    
     Similar to this, the main electrode portion  44   a  of the second electrode  44  may continuously elongate along the first direction, and the plurality of insulating members IP may be positioned on the main electrode portion  44   a  to be spaced apart from each other in the first direction. The plurality of insulating members IP may be positioned in an overlap portion of the insulating member IP and the first wiring member  142   a . Further, the connection electrode portion  44   b  may be positioned on the main electrode portion  44   a  to include a portion, in which the plurality of insulating members IP are not positioned, i.e., a portion overlapping at least the second wiring member  142   b . Here, the connection electrode portion  44   b  in the first direction may be the same as a portion overlapping the second wiring member  142   b  or may have a greater length than the portion. In particular, the connection electrode portion  44   b  in the first direction may have a greater length than a portion overlapping the second wiring member  142   b . However, the present disclosure is not limited thereto. For example, the connection electrode portion  44   b  in the first direction may have a smaller length than a portion overlapping the second wiring member  142   b . In this instance, the connection electrode portion  44   b  may be positioned to be spaced apart from the plurality of insulating members IP in the first direction. Hence, the present disclosure can simplify the manufacturing process of the connection electrode portion  44   b  and reduce the material cost by reducing an area of the connection electrode portion  44   b.    
       FIG. 7  and the above description have illustrated and described that the adhesive layer LSP is positioned between the connection electrode portions  42   b  and  44   b  and the wiring member  142 . For example, the adhesive layer LSP between the connection electrode portions  42   b  and  44   b  and the wiring member  142  may contact the connection electrode portions  42   b  and  44   b  and the wiring member  142 . Hence, the adhesive layer LSP may serve to temporarily fix the connection electrode portions  42   b  and  44   b  and the wiring member  142  and to stably attach the connection electrode portions  42   b  and  44   b  and the wiring member  142 . 
     For the simple illustration and the clear understanding, in the present disclosure, in the cross-sectional view of the drawing, for example,  FIG. 7 , the adhesive layer LSP is positioned on only the connection electrode portions  42   b  and  44   b  and is positioned on the insulating member IP. However, the adhesive layer LSP may actually have a straight shape in which it elongates along the second direction and is formed over the plurality of connection electrode portions  42   b  and  44   b  and the plurality of insulating members IP along the extension direction of the wiring member  142 . However, the present disclosure is not limited thereto, and the shape, the arrangement, etc. of the adhesive layer LSP may be variously changed. 
     For another example, as illustrated in  FIG. 8 , in a plurality of overlap portions of the electrodes  42  and  44  and the wiring portions  140 , in an overlap portion in which the electrodes  42  and  44  and the wiring portions  140  need to be electrically connected to each other, the electrodes  42  and  44  (the connection electrode portions  42   b  and  44   b ) and the wiring portions  140  may directly contact each other and may be connected. More specifically, the first wiring member  142   a  may directly contact the first electrode  42  included in each solar cell  10  and may be electrically connected to the first electrode  42 , and the second wiring member  142   b  may directly contact the second electrode  44  included in each solar cell  10  and may be electrically connected to the second electrode  44 . 
     A method of manufacturing the solar cell  10  having the above-described structure and the solar cell panel  100  including the same is described in detail below with reference to  FIGS. 9 a  to 9 f    and  FIG. 10  along with  FIGS. 1 to 8 .  FIGS. 9 a  to 9 f    are cross-sectional views partially illustrating a method for manufacturing the solar cell panel  100  according to an embodiment of the present disclosure.  FIG. 10  schematically illustrates metal particles  426   b  included in a paste used for forming the connection electrode portion  42   b  in a method for manufacturing the solar cell panel  100  according to an embodiment of the present disclosure. A detailed description of the part that has been already described above is omitted, and an undescribed part is chiefly described in detail. 
     Referring to  FIG. 9 a   , the interlayer  20 , the first conductivity type region  32 , the second conductivity type region  34 , the barrier region  36 , the back passivation layer  40 , the insulating layer  41 , etc. are formed on the back surface of the semiconductor substrate  12 , and the front surface field region  12   b , the front passivation layer  24 , the anti-reflection layer  26 , etc. are formed on the front surface of the semiconductor substrate  12  to form a photoelectric conversion unit. In this case, the contact hole  46  has been formed in the back passivation layer  40  in accordance with a portion where an electrode ( 42  and  44  in  FIG. 9 c   , hereinafter the same) will be formed. 
     The order, method, etc. for forming the interlayer  20 , the first conductivity type region  32 , the second conductivity type region  34 , the barrier region  36 , the back passivation layer  40 , the insulating layer  41 , the front surface field region  12   b , the front passivation layer  24 , the anti-reflection layer  26 , etc. may be changed in various ways. 
     For example, various processes known as the texturing of the semiconductor substrate  12  may be used. The interlayer  20  or the insulating layer  41  may be formed by a thermal growth method, a deposition method (e.g., plasma enhanced chemical vapor deposition (PECVD) or an atomic layer deposition (ALD) method), etc. The first and second conductivity type regions  32  and  34  may be formed by doping a dopant into a semiconductor layer formed by a thermal growth method, a deposition method (e.g., low pressure chemical vapor deposition (LPCVD)), etc. The doping of the dopant may be performed in a process of forming the semiconductor layer or may be performed in a doping process performed after the semiconductor layer is formed. The front surface field region  12   b  may be formed by various doping processes. An ion implantation method, a thermal diffusion method, a laser doping method, etc. may be performed as the doping process. The front passivation layer  24 , the anti-reflection layer  26  or the back passivation layer  40  may be formed by various methods, such as a chemical vapor deposition method, a vacuum deposition method, a spin coating method, a screen printing method, and a spray coating method. The contact hole  46  may be formed by various methods, such as laser etching and wet etching. 
     Next, as illustrated in  FIGS. 9 b  to 9 d   , the first and second electrodes  42  and  44  including the main electrode portions  42   a  and  44   a  and the connection electrode portions  42   b  and  44   b  may be formed. The first and second electrodes  42  and  44  may be formed to fill the contact hole  46 . For example, in the present embodiment, a step of forming the insulating member IP is performed between a step of forming the main electrode portions  42   a  and  44   a  and a step of forming the connection electrode portions  42   b  and  44   b . This is described in detail below. 
     As illustrated in  FIG. 9 b   , the main electrode portions  42   a  and  44   a  may be formed on the conductivity type regions  32  and  34  to fill the contact hole  46 . The main electrode portions  42   a  and  44   a  may be formed by sputtering. 
     The main electrode portions  42   a  and  44   a  of the first and second electrodes  42  and  44  may be formed by performing the sputtering on the semiconductor substrate  12  and the conductivity type regions  32  and  34  (or the insulating layer  41  positioned on the conductivity type regions), sequentially forming entirely a plurality of material electrode layers on the semiconductor substrate  12  and the conductivity type regions  32  and  34  (or the insulating layer  41  formed on the conductivity type regions) and the plurality of electrode material layers, and then patterning them. The patterning method may be performed using an etchant, an etching paste, and dry etching, etc. For example, the main electrode portions  42   a  and  44   a  may be patterned by applying a resist paste on a portion where the main electrode portions  42   a  and  44   a  need to be formed, and etching a remaining portion using an etchant. Thereafter, the resist paste is removed. Other various methods can be used. 
     Next, as illustrated in  FIG. 9 c   , the insulating member IP is formed. The insulating member IP may be formed to have a desired pattern by the printing, etc. 
     Next, as illustrated in  FIG. 9 d   , the connection electrode portions  42   b  and  44   b  are formed on the main electrode portions  42   a  and  44   a . The connection electrode portions  42   b  and  44   b  may be formed by the printing. As illustrated in  FIG. 9 e   , the adhesive layer LSP is formed on the connection electrode portions  42   b  and  44   b . As illustrated in  FIG. 9 f   , the wiring member  142  is positioned on the electrodes  42  and  44  and the insulating member IP to attach the wiring portion  140 . 
     More specifically, the connection electrode portions  42   b  and  44   b  may be formed by coating a paste forming the connection electrode portions  42   b  and  44   b  on the main electrode portions  42   a  and  44   a , drying the paste, and performing a heat treatment on the dried paste to anneal it. 
     The paste forming the connection electrode portion  42   b  may include metal particles  426   b  including a first metal, a solder material including a second metal different from the first metal, an adhesive material, and the like. In addition, the past may further include a solvent, an additive, etc. In the present embodiment, since the connection electrode portions  42   b  and  44   b  do not require the fire-through passing through the insulating layer, they do not include a glass frit. 
     The metal particles  426   b  included in the paste and including the first metal may include various materials or various shapes. That is, as illustrated in (a) of  FIG. 10 , the metal particles  426   b  may be particles formed of the first metal. Alternatively, as illustrated in (b) of  FIG. 10 , the metal particles  426   b  may include a core layer  4260  including the first metal, and a coating layer  4280  that is coated on the core layer  4260  and includes an organic material or a metal (e.g., tin) different from copper. For example, the metal particles  426   b  may include copper particles, copper particles coated with an organic material, or copper particles coated with a different metal (e.g., tin) from copper. 
     If the metal particles  426   b  use particles formed of the first metal, they can reduce the material cost and have a low resistivity. 
     If the metal particles  426   b  use copper particles coated with an organic material, they can prevent oxidation in advance and prevent electrical conductivity from being greatly reduced, and thus may not affect the efficiency of the solar cell  10 . For example, if the metal particles  426   b  are copper particles coated with an organic material, when a total volume of the metal particles  426   b  is 100, a volume ratio of the coating layer  4280  may be 15 to 30. This is in consideration of electrical conductivity, etc., but the present disclosure is not limited thereto. 
     If the metal particles  426   b  use copper particles coated with a different metal (e.g., tin), they can improve connection characteristics with the main electrode portions  42   a  and  44   a  and the wiring member  142 . For example, if the metal particles  426   b  are copper particles coated with a different metal, when a total volume of the metal particles  426   b  is 100, a volume ratio of the coating layer  4280  may be 5 to 50. This is in consideration of electrical conductivity, etc., but the present disclosure is not limited thereto. 
     If the metal particles  426   b  use copper particles coated with an organic material or a different metal (e.g., tin) from copper, the particle connection layer  428  may include a first portion and a second portion in which an amount of the first metal is less than that in the first portion. 
     The solder material including the second metal may be a material that enables soldering. For example, the second metal may be tin (Sn), and the solder material may consist of only the second metal or may be an alloy further including other metal. For example, soldering characteristics may be further improved by using a tin-silver-copper (Sn—Ag—Cu, SAC)-based alloy as a solder material. 
     The adhesive material may include an organic material, an inorganic material, etc. as a material capable of improving soldering characteristics, and may have non-conductive properties. For example, the adhesive material may be a material including both an organic material and an inorganic material, for example, a flux including carbon, oxide, rosin, etc. The flux may include carbon, oxide, rosin, etc., and serve to improve adhesion characteristics between the connection electrode portion  42   b  and the wiring portion  140  during soldering. In addition, the flux may include an additive for effective dispersion. However, the present disclosure is not limited thereto, and various materials capable of improving the adhesion characteristics of the wiring member  142  may be used as the adhesive material. 
     Here, when a total volume of the metal particles, the solder material, and the adhesive material is 100, a volume ratio of the adhesive material is 30 to 70. As described above, a sufficient amount of the adhesive material is included, and may serve as a solder paste improving an adhesive force between the connection electrode portion  42   b  and the wiring member  142 . When a total volume of the metal particles  426   b  and the solder material is 100, a volume ratio of the metal particles may be 15 to 80, and a volume ratio of the solder material may be 20 to 85. This is limited to a range that can sufficiently implement the roles of the metal particles  426   b  and the solder material. For example, a volume of the solder material may be equal to or greater than a volume of the metal particles  426   b . Hence, the solder material can efficiently implement a role of the solder paste improving the adhesive force between the connection electrode portion  42   b  and the wiring member  142 . However, the present disclosure is not limited thereto. The particle diameter, volume, weight, etc. of the metal particles, the solder material, and the adhesive material may be variously changed. 
     The paste includes a solvent, but the solvent may become volatile upon the heat treatment. Hence, the solvent may not be included in the connection electrode portions  42   b  and  44   b  or a very small amount of the solvent may be included in the connection electrode portions  42   b  and  44   b . An organic solvent may be used as the solvent. For example, butyl carbitol acetate (BCA), cellulose acetate (CA), etc. may be used as the solvent, but the present disclosure is not limited thereto. For example, the paste may further include an additive, a binder, etc. 
     The paste may be coated on only a portion corresponding to the main electrode portions  42   a  and  44   a . For example, the paste for forming the connection electrode portions  42   b  and  44   b  may be coated by screen printing using a mask. However, the present disclosure is not limited thereto. 
     The paste coated on the main electrode portions  42   a  and  44   a  is dried at a first temperature. The first temperature is higher than a room temperature and may be 150° C. or less, but the present disclosure is not limited thereto. The first temperature may have other values. A problem, such as that the paste undesirably flows down, can be prevented by drying the paste. If heat treatment is directly performed without performing the dry step, a problem, such as a crack, may occur due to a temperature difference. Heat treatment for hardening is performed after the fluidity of the paste is reduced by drying the paste at a temperature lower than a heat treatment temperature. 
     The heat treatment for hardening (annealing heat treatment) is performed on the dried paste at a second temperature that is higher than the first temperature and that is lower than a melting point of the first metal (i.e., a higher melting point of melting points of the first and second metals. In this case, the second temperature may be higher than the melting point of the second metal (i.e., a lower melting point of the melting points of the first and second metals). For example, the second temperature may be 450° C. or less (e.g., 180 to 280° C.). However, the present disclosure is not limited thereto, and the second temperature may have other values. The heat treatment process, as illustrated in  FIG. 9 f   , may be performed by a reflow process performed after the wiring member  142  is positioned on the electrodes  42  and  44 . If the heat treatment of the paste for forming the connection electrode portion  42   b  is performed together in the reflow process, the process can be simplified. 
     When the heat treatment is performed on the dried paste, the solvent is volatile and heat is applied to the first and second metals. When heat is applied to the first metal and the second metal, the first metal is aggregated with the first metal together, and the second metal is aggregated with the second metal together. In this case, the adhesion characteristics with the connection electrode portions  42   b  and  44   b  can be improved by the adhesive material. The adhesive material can also improve the adhesion characteristics with the wiring portion  140 . 
     More specifically, when the metal particles  426   b  including the first metal and the solder material including the second metal are provided in the heat treatment process, the second metal of the solder material melts and flows out. Hence, the metal particles  426   b  are aggregated to form the particle connection layer  426 , and the molten and flowed-out second metals are aggregated on the outer surface of the particle connection layer  426 , thereby forming the cover layer  428  covering the particle connection layer  426 . In this case, if the first metal includes copper, copper can effectively deliver heat to the second metal since copper is easily aggregated when heat is applied to copper, and easily absorbs heat. Accordingly, the second metal can move more smoothly to the outer surface of the particle connection layer  426  and can be aggregated together on the outer surface. 
     In this case, the particles  426   b  of the particle connection layer  426  are not sintered, but contact with each other and are aggregated to have conductivity by hardening simply. The binder or the second metal may remain between the metal particles  426   b  of the particle connection layer  426  formed by simple hardening as described above to form remaining portions  428   a  and  428   b . A gap (v in  FIG. 1 , hereinafter the same) may remain in a part between the metal particles  426   b . Hence, the connection electrode portions  42   b  and  44   b  may have a higher gap ratio than the main electrode portions  42   a  and  44   a  not having the gap v. The main electrode portions  42   a  and  44   a  comprised of a sputtering layer and the connection electrode portions  42   b  and  44   b  comprised of a printing layer may be identified based on a difference in the gap ratio. For reference, the main electrode portion  42   a  comprised of the sputtering layer and the connection electrode portion  42   b  comprised of the printing layer may be identified based on a cross-sectional shape or an external surface shape in a micrograph or may be identified depending on whether a binder is present through component analysis. 
     In the heat treatment step, an intermetallic compound (IMC) layer  420  (see  FIG. 3 ), in which a metal included in the main electrode portions  42   a  and  44   a  and the second metal are mixed, may be formed between the main electrode portions  42   a  and  44   a  and the connection electrode portions  42   b  and  44   b.    
       FIGS. 9 a  to 9 f    and the description thereof illustrate that the step of forming the insulating member IP is performed between the step of forming the main electrode portions  42   a  and  44   a  and the step of forming the connection electrode portions  42   b  and  44   b , by way of example. However, the present disclosure is not limited thereto. Thus, in an embodiment illustrated in  FIG. 12 , the step of forming the insulating member IP may be performed between the step of forming the photoelectric conversion unit and the step of forming the electrodes  42  and  44 . When the step of forming the insulating member IP is performed before the step of forming the connection electrode portions  42   b  and  44   b  as described above, a process of removing an oxide layer of the main electrode portions  42   a  and  44   a  (for example, plasma process) may be performed after the step of forming the insulating member IP. Hence, the connection characteristics of the main electrode portions  42   a  and  44   a  and the connection electrode portions  42   b  and  44   b  can be improved by exposing a portion, in which the connection electrode portions  42   b  and  44   b  will be formed, while protecting the main electrode portions  42   a  and  44   a  by the insulating member IP. 
     However, the present disclosure is not limited thereto. For another example, in an embodiment illustrated in  FIG. 13 , the insulating member IP may be formed after forming the electrodes  42  and  44  including the main electrode portions  42   a  and  44   a  and the connection electrode portions  42   b  and  44   b . Various other modifications can be used. 
       FIGS. 9 a  to 9 f    illustrate that in the reflow process performed after the wiring member  142  is positioned on the electrodes  42  and  44 , the heat treatment of the paste for forming the connection electrode portions  42   b  and  44   b  is performed, by way of example. However, the present disclosure is not limited thereto. The heat treatment for forming the connection electrode portions  42   b  and  44   b  may be performed in various steps. For example, before for performing the process of forming the adhesive layer LSP, the process of positioning the wiring member  142 , etc., the heat treatment for forming the connection electrode portions  42   b  and  44   b  may be immediately performed without another process after coating and drying the paste for forming the connection electrode portions  42   b  and  44   b . Various other modifications can be used. 
     According to the present embodiment, the connection electrode portion  42   b  may serve as an electrode for collecting and delivering electric current with a low electrical resistance, and as a solder paste for adhesion to the wiring portion  140  by including the solder material and the adhesive material. Hence, a separate solder paste layer formed corresponding to each overlap portion is not required for the substantial connection of the wiring portion  140  and the electrodes  42  and  44 . As a result, the solar cell panel  100  can be manufactured through the simple manufacturing process and can have excellent efficiency and output due to a low resistivity. In particular, in the solar cell  10  having the back electrode structure in which both the first and second electrodes  42  and  44  with different polarities are provided on the back surface, the solar cell panel  100  can efficiently improve the output and greatly simplify the manufacturing process by improving the electrode structure for the attachment to the wiring portion  140 . 
     In particular, in the method of manufacturing the solar cell  10  according to the present embodiment, the connection electrode portions  42   b  and  44   b  may be formed by printing the paste including the first metal and the second metal, and thus the electrodes  42  and  44  including the main electrode portions  42   a  and  44   a  and the connection electrode portions  42   b  and  44   b  may be formed through the simple process. In the present embodiment, the second metal can effectively prevent the oxidization of the first metal at the cover layer  428  that is the outermost layer connected to the wiring portion  140  or the adhesive layer LSP. In the related art, before the wiring portion  140  or the adhesive layer LSP is formed, a plasma process for removing an oxide layer formed in the electrodes  42  and  44  has been additionally performed. However, in the present embodiment, the plasma process for removing the oxide layer can be omitted by preventing oxidization at the outermost layer of the electrodes  42  and  44  using the second metal. Accordingly, the present embodiment can simplify the process and fundamentally prevent a problem such as a damage to the electrodes  42  and  44  or the solar cell  10 . 
     Hereinafter, a solar cell panel according to other modified examples of the present disclosure is described in detail. The detailed description of configurations that are the same as or extremely similar to the above description will be omitted, and only a difference will be described in detail. The combinations of the above-described embodiments or modified examples thereof and the following embodiment or modified embodiments thereof are also within the scope of the present disclosure. 
       FIG. 11  is a rear plan view and a partial cross-sectional view thereof schematically illustrating two solar cells, an insulating member, and a wiring portion included in a solar cell panel according to another modified example of the present disclosure. 
     Referring to  FIG. 11 , in this modified example, in a first electrode  42 , a main electrode portion  42   a  may continuously elongate along the first direction, and a plurality of insulating members IP may be positioned on the main electrode portion  42   a  to be spaced apart from each other in the first direction. The plurality of insulating members IP may be positioned in an overlap portion of the insulating member IP and a second wiring member  142   b . Further, a connection electrode portion  42   b  may be positioned on the main electrode portion  42   a  to include a portion, in which the plurality of insulating members IP are not positioned, i.e., a portion overlapping at least a first wiring member  142   a . In this instance, the connection electrode portion  42   b  in the first direction may have a greater length than a portion overlapping the first wiring member  142   a , and may contact two adjacent insulating members IP among the plurality of insulating members IP and extend to connect the two adjacent insulating members IP. Hence, this modified example can simplify a process of forming the connection electrode portion  42   b  by reducing an area of the connection electrode portion  42   b  and can stably connect the connection electrode portion  42   b  to the first wiring member  142   a  while reducing the material cost. 
     Similar to this, in a second electrode, a main electrode portion may continuously elongate along the first direction, and a plurality of insulating members IP may be positioned on the main electrode portion to be spaced apart from each other in the first direction. The plurality of insulating members IP may be positioned in an overlap portion of the insulating member IP and a first wiring member  142   a . Further, a connection electrode portion may be positioned on the main electrode portion to include a portion, in which the plurality of insulating members IP are not positioned, i.e., a portion overlapping at least a second wiring member  142   b . In this instance, the connection electrode portion in the first direction may have a greater length than a portion overlapping the second wiring member  142   b , and may contact two adjacent insulating members IP among the plurality of insulating members IP and extend to connect the two adjacent insulating members IP. Hence, this modified example can simplify a process of forming the connection electrode portion by reducing an area of the connection electrode portion and can stably connect the connection electrode portion to the first wiring member  142   a  while reducing the material cost. 
       FIG. 12  is a rear plan view and a partial cross-sectional view thereof schematically illustrating two solar cells, an insulating member, and a wiring portion included in a solar cell panel according to another modified example of the present disclosure. 
     Referring to  FIG. 12 , this modified example may include a plurality of insulating members IP positioned to be spaced apart from each other in the first direction, and main electrode portions  42   a  and  44   a  and connection electrode portions  42   b  and  44   b  may be positioned between the plurality of insulating members IP. In this instance, the connection electrode portions  42   b  and  44   b  may be formed to include entirely an overlap portion of electrodes  42  and  44  and a wiring portion  140  that have to be electrically connected to each other. Hence, the plurality of main electrode portions  42   a  and  44   a  and the plurality of connection electrode portions  42   b  and  44   b  corresponding to one first electrode  42  or one second electrode  44  may be provided to be spaced apart from each other at a predetermined distance in the first direction. 
     More specifically, in the first electrode  42 , the plurality of insulating members IP may be positioned on a back passivation layer  40  and/or an insulating layer  41  to be spaced apart from each other in the first direction, and the main electrode portion  42   a  and the connection electrode portion  42   b  may be positioned between the plurality of insulating members IP. The plurality of insulating members IP may be positioned in an overlap portion of the insulating member IP and the second wiring member  142   b . Further, the main electrode portion  42   a  and the connection electrode portion  42   b  may be positioned to include a portion, in which the plurality of insulating members IP are not positioned, i.e., a portion overlapping at least the first wiring member  142   a . In this instance, the main electrode portion  42   a  and/or the connection electrode portion  42   b  in the first direction may have a greater length than a portion overlapping the first wiring member  142   a .  FIG. 12  illustrates that the main electrode portion  42   a  and the connection electrode portion  42   b  contact two adjacent insulating members IP among the plurality of insulating members IP and extend to connect the two adjacent insulating members IP, by way of example. However, the present disclosure is not limited thereto. For example, the main electrode portion  42   a  and/or the connection electrode portion  42   b  may be positioned between two adjacent insulating members IP among the plurality of insulating members IP to be spaced apart from the two adjacent insulating members IP. Hence, this modified example can simplify a process of forming the main electrode portion  42   a  and/or the connection electrode portion  42   b  and improve the insulation properties by reducing an area of the main electrode portion  42   a  and/or the connection electrode portion  42   b  and can stably connect the connection electrode portion  42   b  to the first wiring member  142   a  while reducing the material cost. 
     Similar to this, in the second electrode, the plurality of insulating members IP may be positioned on a back passivation layer  40  and/or an insulating layer  41  to be spaced apart from each other in the first direction, and the main electrode portion and the connection electrode portion may be positioned between the plurality of insulating members IP. The plurality of insulating members IP may be positioned in an overlap portion of the insulating member IP and the first wiring member  142   a . Further, the main electrode portion and the connection electrode portion may be positioned to include a portion, in which the plurality of insulating members IP are not positioned, i.e., a portion overlapping at least the second wiring member  142   b . In this instance, the main electrode portion and/or the connection electrode portion in the first direction may have a greater length than a portion overlapping the first wiring member  142   a . Here, the main electrode portion and the connection electrode portion may contact two adjacent insulating members IP among the plurality of insulating members IP and extend to connect the two adjacent insulating members IP. However, the present disclosure is not limited thereto. For example, the main electrode portion and/or the connection electrode portion may be positioned between two adjacent insulating members IP among the plurality of insulating members IP to be spaced apart from the two adjacent insulating members IP. Hence, this modified example can simplify a process of forming the main electrode portion and/or the connection electrode portion and improve the insulation properties by reducing an area of the main electrode portion and/or the connection electrode portion and can stably connect the connection electrode portion to the second wiring member  142   b  while reducing the material cost. 
       FIG. 13  is a rear plan view and a partial cross-sectional view thereof schematically illustrating two solar cells, an insulating member, and a wiring portion included in a solar cell panel according to another modified example of the present disclosure. 
     Referring to  FIG. 13 , in a first electrode  42 , a main electrode portion  42   a  and a connection electrode portion  42   b  may continuously elongate along the first direction, and a plurality of insulating members IP may be positioned on the main electrode portion  42   a  and the connection electrode portion  42   b  to be spaced apart from each other in the first direction. The plurality of insulating members IP may be positioned in an overlap portion of the insulating member IP and a second wiring member  142   b . Hence, this modified example can stably connect the connection electrode portion  42   b  to the first wiring member  142   a  by forming entirely the connection electrode portion  42   b.    
     Similar to this, in a second electrode, a main electrode portion and a connection electrode portion may continuously elongate along the first direction, and a plurality of insulating members IP may be positioned on the main electrode portion and the connection electrode portion to be spaced apart from each other in the first direction. The plurality of insulating members IP may be positioned in an overlap portion of the insulating member IP and a first wiring member  142   a . Hence, this modified example can stably connect the connection electrode portion to the second wiring member  142   a  by forming entirely the connection electrode portion. 
     The above description is given based on that the first and second electrodes  42  and  44  have the same structure, by way of example. However, the present disclosure is not limited thereto, and the first and second electrodes  42  and  44  may have different structures.  FIGS. 11 to 13  illustrate that the adhesive layer LSP is provided in the same manner as  FIG. 7 , by way of example. However, the present disclosure is not limited thereto. Thus, the adhesive layer LSP may not be provided in the same manner as  FIG. 8 , and various other modifications can be used. 
     Hereinafter, a solar cell panel and a method for manufacturing the same according to other embodiments of the present disclosure are described in detail. The detailed description of configurations that are the same as or extremely similar to the above description will be omitted, and only a difference will be described in detail. The combinations of the above-described embodiments or modified examples thereof and the following embodiment or modified embodiments thereof are also within the scope of the present disclosure. 
       FIG. 14  is a rear plan view and a partial cross-sectional view thereof schematically illustrating two solar cells, an insulating member, and a wiring portion included in a solar cell panel according to another embodiment of the present disclosure. 
     Referring to  FIG. 14 , in the present embodiment, in a first electrode  42 , a main electrode portion  42   a  may continuously elongate along the first direction, and a plurality of insulating members IP may be positioned on the main electrode portion  42   a  to be spaced apart from each other in the first direction. The plurality of insulating members IP may be positioned in an overlap portion of the insulating member IP and a second wiring member  142   b . Further, connection electrode portions  42   b  and  42   c  may be positioned on the main electrode portion  42   a  to include a portion, in which the plurality of insulating members IP are not positioned, i.e., a portion overlapping at least a first wiring member  142   a . In this instance, the connection electrode portions  42   b  and  42   c  in the first direction may have a greater length than a portion overlapping the first wiring member  142   a , and may contact two adjacent insulating members IP among the plurality of insulating members IP and extend to connect the two adjacent insulating members IP. Hence, the present embodiment can simplify a process of forming the connection electrode portions  42   b  and  42   c  by reducing an area of the connection electrode portions  42   b  and  42   c  and can stably connect the connection electrode portions  42   b  and  42   c  to the first wiring member  142   a  while reducing the material cost. 
     In this instance, the connection electrode portions  42   b  and  42   c  of the first electrode  42  include a first connection electrode portion  42   b  formed corresponding to a portion in which the first wiring member  142   a  is to be positioned, and a second connection electrode portion  42   c  including a different material from the first connection electrode portion  42   b . For example, the first connection electrode portion  42   b  may be formed to include a portion of the first electrode  42  in which the first wiring member  142   a  is to be positioned, and the second connection electrode portion  42   c  may be extended to connect the first connection electrode portion  42   b  and the insulating member IP in the first electrode  42 . Hence, the connection electrode portions  42   b  and  42   c  including the first and second connection electrode portions  42   b  and  42   c  may be extended to connect at least the plurality of insulating members IP, and the connection electrode portions  42   b  and  42   c  may be entirely positioned on the portion in which the plurality of insulating members IP are not positioned. 
     Here, the first connection electrode portion  42   b  may include the first metal, the solder material including the second metal, and the adhesive material in the same manner as the connection electrode portion  42   b  according to the above-described embodiment. That is, the description of the connection electrode portion  42   b  according to the above-described embodiment can be applied to the first connection electrode portion  42   b  according to the present embodiment as it is. Hence, a detailed description of the first connection electrode portion  42   b  is omitted. 
     The second connection electrode portion  42   c  may include the first metal, the solder material including the second metal, and a binder. The first metal, the second metal, and the solder material including the second metal may be the same as or extremely similar to the connection electrode portion  42   c  according to the above-described embodiment, and thus a detailed description thereof is omitted. The binder may include a resin consisting of a non-conductive organic material. For example, the binder may include ethyl cellulose binder. The binder can improve adhesion characteristics with the main electrode portion  42   a.    
     In the present embodiment, an adhesive force between the first connection electrode portion  42   b  and the first wiring member  142   a  may be greater than an adhesive force between the second connection electrode portion  42   c  and the first wiring member  142   a . This is because the first connection electrode portion  42   b  includes an adhesive material capable of improving soldering characteristics with the first wiring member  142   a , and the second connection electrode portion  42   c  includes the binder considering only the attachment to the main electrode portion  42   a.    
     A resistivity of the second connection electrode portion  42   c  may be less than a resistivity of the first connection electrode portion  42   b . For example, an amount of the first metal included in the first connection electrode portion  42   b  may be less than an amount of the first metal included in the second connection electrode portion  42   c . The present embodiment can improve the efficiency of the solar cell  10  and the output of the solar cell panel  100  by disposing the second connection electrode portion  42   c  in a portion, that does not directly contact the first wiring member  142   a  as described above, to thereby reduce the resistance of the first electrode  42 . 
     Similar to this, in a second electrode  44 , a main electrode portion  44   a  may continuously elongate along the first direction, and a plurality of insulating members IP may be positioned on the main electrode portion  44   a  to be spaced apart from each other in the first direction. The plurality of insulating members IP may be positioned in an overlap portion of the insulating member IP and a first wiring member  142   a . Further, connection electrode portions  44   b  and  44   c  may be positioned on the main electrode portion  44   a  to include a portion, in which the plurality of insulating members IP are not positioned, i.e., a portion overlapping at least a second wiring member  142   b . In this instance, the connection electrode portions  44   b  and  44   c  in the first direction may have a greater length than a portion overlapping the second wiring member  142   b , and may contact two adjacent insulating members IP among the plurality of insulating members IP and extend to connect the two adjacent insulating members IP. Hence, the present embodiment can simplify a process of forming the connection electrode portions  44   b  and  44   c  by reducing an area of the connection electrode portions  44   b  and  44   c  and can stably connect the connection electrode portions  44   b  and  44   c  to the second wiring member  142   b  while reducing the material cost. 
     In this instance, the connection electrode portions  44   b  and  44   c  of the second electrode  44  include a first connection electrode portion  44   b  formed corresponding to a portion in which the second wiring member  142   b  is to be positioned, and a second connection electrode portion  44   c  including a different material from the first connection electrode portion  44   b . For example, the first connection electrode portion  44   b  may be formed to include a portion of the second electrode  44  in which the second wiring members  142   b  is to be positioned, and the second connection electrode portion  44   c  may be extended to connect the first connection electrode portion  44   b  and the insulating member IP in the first electrode  42 . Hence, the connection electrode portions  44   b  and  44   c  including the first and second connection electrode portions  44   b  and  44   c  may be extended to connect at least the plurality of insulating members IP, and the connection electrode portions  44   b  and  44   c  may be entirely positioned on the portion in which the plurality of insulating members IP are not positioned. 
     Here, the first connection electrode portion  44   b  may include the first metal, the solder material including the second metal, and the adhesive material, and the second connection electrode portion  44   c  may include the first metal, the solder material including the second metal, and a binder. The description of the first and second connection electrode portions  42   b  and  42   c  of the first electrode  42  can be applied to the first and second connection electrode portions  44   b  and  44   c  of the second electrode  44 , as it is, and thus a detailed description thereof is omitted. 
     In the present embodiment, an adhesive force between the first connection electrode portion  44   b  and the second wiring member  142   b  may be greater than an adhesive force between the second connection electrode portion  44   c  and the second wiring member  142   b . Further, a resistivity of the second connection electrode portion  44   c  may be less than a resistivity of the first connection electrode portion  44   b . For example, an amount of the first metal included in the first connection electrode portion  44   b  may be less than an amount of the first metal included in the second connection electrode portion  44   c . The present embodiment can improve the efficiency of the solar cell  10  and the output of the solar cell panel  100  by disposing the second connection electrode portion  44   c  in a portion, that does not directly contact the second wiring member  142   b  as described above, to thereby reduce the resistance of the second electrode  44 . 
       FIG. 14  illustrates that the insulating members IP are positioned on the main electrode portions  42   a  and  44   a , and the connection electrode portions  42   b  and  42   c  and  44   b  and  44   c  are positioned on the main electrode portions  42   a  and  44   a  and between the insulating members IP, by way of example. However, the present disclosure is not limited thereto. 
     As a modified example, as illustrated in  FIG. 15 , the insulating members IP may be positioned on the main electrode portions  42   a  and  44   a  and the connection electrode portions  42   b  and  42   c  and  44   b  and  44   c . In this case, the second connection electrode portions  42   c  and  44   c  may be formed to be connected to the neighboring first connection electrode portions  42   b  and  44   b  by passing the lower part of the insulating members IP. Hence, the connection electrode portions  42   b  and  42   c  and  44   b  and  44   c  including the first and second connection electrode portions  42   b  and  42   c  and  44   b  and  44   c  may be positioned entirely in the first and second electrodes  42  and  44 . 
     As another modified example, the insulating members IP may be positioned to be spaced apart from each other at a predetermined distance in the first direction, and the main electrode portions  42   a  and  44   a  and the connection electrode portions  42   b  and  42   c  and  44   b  and  44   c  may be extended to connect at least the plurality of insulating members IP. Hence, the connection electrode portions  44   b  and  44   c  may be positioned entirely in a portion in which the plurality of insulating members IP are not positioned. 
     The above description is given based on that the first and second electrodes  42  and  44  have the same structure, by way of example. However, the present disclosure is not limited thereto, and the first and second electrodes  42  and  44  may have different structures.  FIGS. 14 and 15  illustrate that the adhesive layer LSP is provided in the same manner as  FIG. 7 , by way of example. However, the present disclosure is not limited thereto. Thus, the adhesive layer LSP may not be provided in the same manner as  FIG. 8 , and various other modifications can be used. 
     In addition, the embodiments described above are given based on the solar cell  10  with the back electrode structure, but the present disclosure is not limited thereto. Hence, even in a solar cell in which the first and second electrodes  42  and  44  are positioned on the opposite surfaces, at least one of the first and second electrodes  42  and  44  may have the above-described structure. In this instance, the wiring member  142  may be directly connected to the connection electrode portions  42   b  and  44   b , or may be connected to the connection electrode portions  42   b  and  44   b  by the adhesive layer LSP (e.g., low temperature solder paste) and may be connected to the connection electrode portions  42   b  and  44   b  without a separate solder paste layer (e.g., high temperature solder paste). Various other modifications can be used. 
     The features, structures, effects and the like according to the above-described embodiments are included in at least one embodiment of the present disclosure, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified in other embodiments by those skilled in the art to which the embodiments belong. Accordingly, contents related to these combinations and modifications should be construed as being included in the scope of the present disclosure.