Solar cell module

A solar cell module includes a plurality of solar cells and includes first and second solar cells positioned adjacent to each other in a first direction, the solar cell module further comprises a connector for connecting hole terminals of the first solar cell to electron terminals of the second solar cell, the hole terminals being positioned on the first solar cell and being separated from each other and the electron terminals being positioned on the second solar cell and being separated from each other. The hole terminals and the electron terminals of each solar cell are positioned parallel to a first side of each solar cell, the connector is positioned parallel to a second side crossing the first side of each solar cell, and the connector is positioned on the same side of the first and second solar cells.

This application claims priority to and the benefit of Korean Patent Application No. 10-2011-0046875, filed in the Korean Intellectual Property Office on May 18, 2011, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

Embodiments of the invention relate to a solar cell module.

Description of the Related Art

Recently, as existing energy sources such as petroleum and coal are expected to be depleted, interests in alternative energy sources for replacing the existing energy sources are increasing. Among the alternative energy sources, solar cells for generating electric energy from solar energy have been particularly spotlighted.

A solar cell generally includes semiconductor parts, which respectively have different conductive types, for example, a p-type and an n-type and thus form a p-n junction, and electrodes respectively connected to the semiconductor parts of the different conductive types.

When light is incident on the solar cell, electrons and holes are produced in the semiconductor parts. The electrons move to the n-type semiconductor part, and the holes move to the p-type semiconductor part. Then, the electrons and the holes are collected by the different electrodes respectively connected to the n-type semiconductor part and the p-type semiconductor part. The electrodes are connected to each other using electric wires to thereby obtain electric power.

A plurality of solar cells having the above-described configuration are connected in series or parallel to one another to manufacture a panel type solar cell module capable of obtaining a desired output.

SUMMARY OF THE INVENTION

In one aspect, there is a solar cell module including a plurality of solar cells each including a substrate of a first conductive type, a plurality of hole terminals and a plurality of electron terminals, the plurality of hole terminals and the plurality of electron terminals being positioned opposite an incident surface of the substrate on which light is incident, a first protective layer positioned on the incident surfaces of the plurality of solar cells, a transparent member positioned on the first protective layer, and a second protective layer positioned on surfaces opposite the incident surfaces of the plurality of solar cells, wherein the plurality of solar cells include a first cell and a second solar cell positioned adjacent to each other in a first direction, wherein the solar cell module further includes a connector for connecting hole terminals of the first solar cell to electron terminals of the second solar cell, the hole terminals being positioned on the first solar cell and being separated from each other and the electron terminals being positioned on the second solar cell and being separated from each other, wherein the plurality of hole terminals and the plurality of electron terminals of each solar cell are positioned parallel to a first side of each solar cell, wherein the connector is positioned parallel to a second side crossing the first side of each solar cell, and wherein the connector is positioned on the same side of the first and second solar cells.

The first side may be parallel to a surface of a short axis of the solar cell module and the second surface may be parallel to a surface of a long axis of the solar cell module.

The third connector may directly connect the hole terminals of the first solar cell and the electron terminals of the second solar cell.

The solar cell module may further include a plurality of first connectors directly connected to the plurality of hole terminals of the plurality of solar cells and a plurality of second connectors directly connected to the plurality of electron terminals of the plurality of solar cells. First connectors of the first solar cell and second connectors of the second solar cell may be connected to one another using the connector being a third connector.

The third connector extends in a direction crossing the plurality of first and second connectors.

The third connector may be entirely positioned outside the first and second solar cells.

Portions of the first connectors of the first solar cell and portions of the second connectors of the second solar cell protrude to the outside of the first and second solar cells and are connected to the third connector.

The plurality of solar cells may further include third and fourth solar cells positioned adjacent to each other in a first direction parallel to the first side. The solar cell module may further include a fourth connector, which is connected to the first connectors of the third solar cell and to the second connectors of the fourth solar cell.

The fourth connector may be entirely positioned outside the third and fourth solar cells.

The fourth connector may be positioned on different sides of the third and fourth solar cells.

The solar cell module may further include a back sheet positioned under the second protective layer. The connector may be formed on the back sheet in a pattern shape.

The second protective layer may include openings exposing the plurality of hole terminals and the plurality of electron terminals.

A distance between the hole terminals of each of the first and second solar cells and the second side of each of the first and second solar cells adjacent to the hole terminals may be different from a distance between the electron terminals of each of the first and second solar cells and the second side of each of the first and second solar cells adjacent to the electron terminals.

The connector may directly connect the hole terminals of the first solar cell or the second solar cell to the electron terminals of the second solar cell or the first solar cell. A distance between the hole terminals and the electron terminals connected to the connector and the second sides of the first and second solar cells may be less than a distance between the electron terminals and the hole terminals not connected to another connector and the second sides of the first and second solar cells.

The plurality of solar cells may further include third and fourth solar cells positioned adjacent to each other in a first direction parallel to the first side. A terminal disposed adjacent to the second side of the third solar cell may be the same kind of terminal disposed adjacent to the second side of the fourth solar cell.

The third connector may be positioned to overlap the first and second solar cells.

The plurality of solar cells may further include third and fourth solar cells positioned adjacent to each other in a first direction parallel to the first side. The solar cell module may further include a another connector connected to hole terminals of the third solar cell and to electron terminals of the fourth solar cell.

A distance between the hole terminals and the electron terminals connected to the another connector and the second sides of the third and fourth solar cells may be less than a distance between the electron terminals and the hole terminals not connected to the another connector and the second sides of the third and fourth solar cells.

The another connector may be positioned to overlap the third and fourth solar cells.

DETAILED DESCRIPTION OF THE EMBODIMENTS

A solar cell module according to an example embodiment of the invention is described in detail with reference to the accompanying drawings.

As shown inFIG. 1, a solar cell module100according to an example embodiment of the invention includes a plurality of solar cells1, protective layers20aand20bfor protecting the solar cells1, a transparent member40on the protective layer20a(hereinafter, referred to as an “upper protective layer”) positioned on light receiving surfaces of the solar cells1, a back sheet30positioned under the protective layer20b(hereinafter, referred to as “lower protective layer”) positioned on surfaces, opposite the light receiving surfaces, on which light is not incident, a pattern forming part50positioned under the back sheet30, and a frame60for receiving the above components1,20a,20b,30,40, and50.

The transparent member40on the light receiving surface of the solar cell module100is formed of a tempered glass having a high transmittance of light to prevent a damage of the solar cell module100. The tempered glass may be a low iron tempered glass containing a small amount of iron. The transparent member40may have an embossed inner surface so as to increase a scattering effect of light.

The upper and lower protective layers20aand20bprevent corrosion of metal resulting from moisture penetration and protect the solar cell module100from an impact. The upper and lower protective layers20aand20band the plurality of solar cells1form an integral body when a lamination process is performed in a state where the upper and lower protective layers20aand20bare respectively positioned on and under the solar cells1. The upper and lower protective layers20aand20bmay be formed of ethylene vinyl acetate (EVA), etc. Other materials may be used.

The back sheet30is formed using a thin sheet formed of an insulating material such as fluoropolymer/polyester/fluoropolymer (FP/PE/FP). Other insulating materials may be used.

The back sheet30prevents moisture and oxygen from penetrating into a back surface of the solar cell module100, thereby protecting the solar cells1from the external environment. The back sheet30may have a multi-layered structure including a moisture/oxygen penetrating prevention layer, a chemical corrosion prevention layer, an insulation layer, etc.

As shown inFIG. 1, the plurality of solar cells1of the solar cell module100are arranged in a matrix structure.

The plurality of solar cells1of the solar cell module100may be generally arranged in the structure of a 6×10 matrix or a 4×9 matrix.

AlthoughFIG. 1shows the solar cells1having the structure of 4×7 matrix in the embodiment of the invention, the number of solar cells1in column and/or row directions may vary, if necessary or desired.

All of the solar cells1have the same structure. In the embodiment of the invention, each solar cell1is a back contact solar cell, in which an electron current collector or an electron electrode serving as a terminal for outputting electrons to the outside, and a hole current collector or a hole electrode serving as a terminal for outputting holes to the outside are formed on a back surface of a substrate of the solar cell1. The back surface of the substrate of the solar cell1is positioned opposite a front surface (i.e., a light incident surface) of the substrate of the solar cell1. Thus, light is not incident on the back surface of the substrate, or only a small amount of light is incident on the back surface of the substrate.

Examples of the back contact solar cell include a metal wrap through (MWT) solar cell, in which both the electron current collector and the hole current collector are positioned on the back surface of the substrate, and an interdigitated back contact (IBC) solar cell, in which both the electron electrode and the hole electrode are positioned on the back surface of the substrate.

FIGS. 2 and 3show the MWT solar cell as an example of the back contact solar cell.

As shown inFIGS. 2 and 3, the MWT solar cell1according to the embodiment of the invention includes a substrate110having a plurality of via holes181, an emitter region120positioned at the substrate110, an anti-reflection layer130positioned on the emitter region120of an incident surface (hereinafter, referred to as “a front surface”) of the substrate110on which light is incident, a plurality of front electrodes141positioned on the emitter region120of the front surface of the substrate110on which the anti-reflection layer130is not positioned, a plurality of back electrodes151positioned on a surface (hereinafter, referred to as “a back surface”) opposite the front surface of the substrate110, a plurality of front electrode current collectors161, a plurality of back electrode current collectors162, and a back surface field (BSF) region171positioned at the back surface of the substrate110. The plurality of front electrode current collectors161are positioned in the via holes181and on the emitter region120of the back surface of the substrate110around the via holes181and are electrically connected to the plurality of front electrodes141. The back electrode current collectors162are positioned on the back surface of the substrate110and are electrically connected to the back electrodes151.

The substrate110is a semiconductor substrate, which may be formed of first conductive type silicon, for example, p-type silicon, though not required. In the embodiment of the invention, silicon may be single crystal silicon or polycrystalline silicon. When the substrate110is of a p-type, the substrate110is doped with impurities of a group III element such as boron (B), gallium (Ga), and indium (In). Alternatively, the substrate110may be of an n-type, and/or be formed of semiconductor materials other than silicon. If the substrate110is of the n-type, the substrate110may be doped with impurities of a group V element such as phosphor (P), arsenic (As), and antimony (Sb).

The surface of the substrate110is textured to form a textured surface corresponding to an uneven surface or having uneven characteristics.FIG. 2shows only an edge of the substrate110and only an edge of the anti-reflection layer130on the substrate110as having a plurality of uneven portions for the sake of brevity. However, the entire front surface of the substrate110is the textured surface having the plurality of uneven portions, and thus the anti-reflection layer130on the front surface of the substrate110has the textured surface having the plurality of uneven portions.

An amount of light reflected from the front surface of the substrate110decreases because of the textured surface of the substrate110having the plurality of uneven portions, and thus an amount of light incident to the inside of the substrate110increases. Further, the size of the front surface of the substrate110and the surface area of the anti-reflection layer130increase because of the textured surface of the substrate110. As a result, an amount of light incident on the substrate110increases.

The emitter region120is a region obtained by doping the substrate110with impurities of a second conductive type (for example, an n-type) opposite the first conductive type of the substrate110, so as to be an n-type semiconductor, for example. Thus, the emitter region120of the second conductive type forms a p-n junction along with the substrate110of the first conductive type.

Among carriers, for example, electrons and holes produced by light incident on the substrate110, the electrons and the holes respectively move to the n-type semiconductor and the p-type semiconductor by a built-in potential difference resulting from the p-n junction between the substrate110and the emitter region120. Thus, when the substrate110is of the p-type and the emitter region120is of the n-type, the holes and the electrons move to the substrate110and the emitter region120, respectively.

Because the emitter region120forms the p-n junction along with the substrate110(i.e., a first conductive region of the substrate110), the emitter region120may be of the p-type when the substrate110is of the n-type unlike the embodiment described above. In this instance, the electrons and the holes move to the substrate110and the emitter region120, respectively.

Returning to the embodiment of the invention, when the emitter region120is of the n-type, the emitter region120may be formed by doping the substrate110with impurities of a group V element such as P, As, and Sb. On the contrary, when the emitter region120is of the p-type, the emitter region120may be formed by doping the substrate110with impurities of a group III element such as B, Ga, and In.

The anti-reflection layer130positioned on the emitter region120of the front surface of the substrate110is formed of hydrogenated silicon nitride (SiNx:H), hydrogenated silicon oxide (SiOx:H), or hydrogenated silicon nitride-oxide (SiNxOy:H), etc. The anti-reflection layer130reduces a reflectance of light incident on the MWT solar cell1and increases selectivity of a predetermined wavelength band, thereby increasing the efficiency of the MWT solar cell1.

The anti-reflection layer130performs a passivation function that converts a defect, for example, dangling bonds existing at and around the surface of the substrate110into stable bonds to thereby prevent or reduce a recombination and/or a disappearance of carriers moving to the surface of the substrate110. Hence, the anti-reflection layer130reduces an amount of carriers lost by the defect at the surface of the substrate110.

The anti-reflection layer130shown inFIG. 2has a single-layered structure. The anti-reflection layer130shown inFIG. 2may have a multi-layered structure such as a double-layered structure and a triple-layered structure. The anti-reflection layer130may be omitted, if desired.

The plurality of front electrodes141are positioned on the emitter region120formed at the front surface of the substrate110and are electrically and physically connected to the emitter region120.

The front electrodes141extend substantially parallel to one another in a fixed direction.

The front electrodes141collect carriers (for example, electrons) moving to the emitter region120and transfer the carriers to the front electrode current collectors161, which are one of the electron current collector and the hole current collector, for example, the electron current collector electrically connected to the front electrodes141through the via holes181. The front electrodes141contain at least one conductive material, for example, silver (Ag).

Each of the plurality of front electrode current collectors161positioned on the back surface of the substrate110is referred to as a bus bar and is formed of at least one conductive material. The front electrode current collectors161extend substantially parallel to one another in a direction crossing an extending direction of the front electrodes141positioned on the front surface of the substrate110and thus have a stripe shape.

As shown inFIGS. 2 and 3, the plurality of via holes181are formed in the substrate110at crossings of the front electrodes141and the front electrode current collectors161. Because at least one of the front electrode141and the front electrode current collector161extends to at least one of the front surface and the back surface of the substrate110through the via hole181, the front electrode141and the front electrode current collector161respectively positioned on the opposite surfaces of the substrate110are connected to each other. Hence, the front electrodes141are electrically and physically connected to the front electrode current collectors161through the via holes181.

The front electrode current collectors161output the carriers transferred from the front electrodes141electrically connected to the front electrode current collectors161to an external device.

In the embodiment of the invention, the front electrode current collectors161may contain the same material as the front electrodes141, for example, silver (Ag).

The back electrodes151on the back surface of the substrate110are positioned to be spaced apart from the front electrode current collectors161adjacent to the back electrodes151.

The back electrodes151are positioned on almost the entire back surface of the substrate110excluding formation portions of the front electrode current collectors161and the back electrode current collectors162on the back surface of the substrate110. Additionally, the back electrodes151may not be positioned at an edge of the back surface of the substrate110.

The back electrodes151collect carriers (for example, holes) moving to the substrate110.

The emitter region120positioned at the back surface of the substrate110has a plurality of expositing portions183that expose a portion of the back surface of the substrate110and surround the front electrode current collectors161.

The expositing portions183block an electrical connection between the front electrode current collectors161collecting electrons or holes, and the back electrodes151collecting holes or electrons, thereby causing the electrons and the holes to move smoothly.

The back electrodes151contain at least one conductive material different from the material of the front electrode current collectors161. For example, the back electrodes151may contain at least one conductive material such as aluminum (Al).

The back electrode current collectors162serving as the hole current collector are positioned on the back surface of the substrate110and are electrically and physically connected to the back electrodes151. Further, the back electrode current collectors162extend substantially parallel to the front electrode current collectors161.

Thus, the back electrode current collectors162collect carriers (for example, holes) transferred from the back electrodes151and output the carriers to the external device.

The back electrode current collectors162are formed of the same material as the front electrode current collectors161. Thus, the back electrode current collectors162contain at least one conductive material, for example, silver (Ag).

In the embodiment of the invention, the back electrode current collectors162have a stripe shape elongated (or extending) in a fixed direction in the same manner as the front electrode current collectors161.

FIG. 4illustrates an example shape or layout of the back surface of the substrate110on which the front electrode current collectors161and the back electrode current collectors162are positioned.

For example,FIG. 4shows the three front electrode current collectors161and the four back electrode current collectors162. However, the number of front electrode current collectors161and the number of back electrode current collectors162may vary, if desired.

As shown inFIG. 4, the front electrode current collectors161and the back electrode current collectors162are alternately positioned on the back surface of the substrate110at a constant distance therebetween. The back electrodes151are positioned in positions between the front electrode current collectors161and the back electrode current collectors162. In this instance, the exposing portions183are formed along the front electrode current collectors161, so as to provide an electrical insulation between the back electrodes151and the front electrode current collectors161. Hence, a portion of the substrate110is exposed through the exposing portions183.

Unlike the configuration illustrated inFIG. 4, each back electrode151and each back electrode current collector162may partially overlap each other in other embodiments of the invention. For example, a portion of an edge of the back electrode current collector162may be positioned on the back electrode151, or a portion of the back electrode151may be positioned on the back electrode current collector162. In this instance, a contact area between the back electrode151and the back electrode current collector162increases, and a contact resistance between the back electrode151and the back electrode current collector162decreases. As a result, a transfer of carriers from the back electrode151to the back electrode current collector162may be stably performed because of the stable contact therebetween.

Alternatively, each back electrode current collector162may have an island shape in which a plurality of conductors are positioned in a fixed direction at a constant distance therebetween. Each of the plurality of conductors may have various cross-sectional shapes such as a rectangle, a triangle, a circle, and an oval. Even in this instance, each conductor may partially overlap the back electrode151.

The back surface field region171is a region (for example, a p+-type region) obtained by more heavily doping a portion of the back surface of the substrate110with impurities of the same conductive type as the substrate110than the substrate110. Because the back surface field region171is positioned at the back surface of the substrate110adjoining the back electrodes151, the back electrodes151are electrically connected to the substrate110through the back surface field region171.

The movement of electrons to the back surface field region171is prevented or reduced and also the movement of holes to the back surface field region171is facilitated because of a potential barrier formed by a difference between impurity concentrations of the substrate110and the back surface field region171. Thus, a recombination and/or a disappearance of electrons and holes in and around the back surface of the substrate110are prevented or reduced, and the movement of desired carriers (for example, holes) is accelerated. As a result, a transfer amount of carriers to the back electrodes151and the back electrode current collectors162increases.

As shown inFIG. 4, all of the plurality of the front electrode current collectors161and the plurality of back electrode current collectors162are positioned on a surface (for example, the back surface) of the substrate110. In this instance, the plurality of front electrode current collectors161are separated from each other and extend in the same direction and the plurality of back electrode current collectors162are separated from each other and extend in the same direction. Further, the front electrode current collector161and the back electrode current collector162are alternately positioned on the back surface of the substrate110. As shown inFIG. 4, the solar cell1does not include an element for connecting all of the plurality of front electrode current collectors161and an element for connecting all of the plurality of back electrode current collectors162, and thereby, all the front electrode current collectors161are electrically and physically separated from each other and all the back electrode current collectors162are also electrically and physically separated from each other.

The IBC solar cell is described below as an example of the back contact solar cell with reference toFIGS. 5 to 7.

Structures and components identical or equivalent to those illustrated inFIGS. 2 to 4are designated with the same reference numerals in the solar cell shown inFIGS. 5 to 7, and a further description may be briefly made or may be entirely omitted.

As shown inFIGS. 5 and 6, the IBC solar cell1according to the embodiment of the invention includes a plurality of emitter regions120aof a second conductive type positioned at a back surface of a substrate110of a first conductive type, a plurality of back surface field regions171aof the first conductive type which are positioned at the back surface of the substrate110to be spaced apart from the plurality of emitter regions120a, a plurality of first electrodes141awhich are positioned on the substrate110and are respectively connected to the plurality of emitter regions120a, a plurality of second electrodes142which are positioned on the substrate110and are respectively connected to the plurality of back surface field regions171a, a back passivation layer192positioned between the adjacent first and second electrodes141aand142, and an anti-reflection layer130positioned on a front surface of the substrate110.

In the embodiment of the invention, the substrate110may be formed of crystalline silicon such as single crystal silicon and polycrystalline silicon. The emitter regions120aand the back surface field regions171amay be formed by injecting impurities of a corresponding conductive type into the substrate110using an impurity diffusion method or an ion implantation method, etc. Thus, the emitter regions120aand the back surface field regions171amay be formed of crystalline silicon in the same manner as the substrate110.

Similar to the front electrodes141and the back electrodes151shown inFIGS. 2 and 3, the first electrodes141aand the second electrodes142collect carriers moving through the emitter regions120aand contain a conductive material such as silver (Ag) and aluminum (Al).

The back passivation layer192may be formed of amorphous silicon. The back passivation layer192performs a passivation function at the back surface of the substrate110and prevents an electrical interference between the first and second electrodes141aand142.

In other embodiments of the invention, the back contact solar cell may be a back contact heterojunction solar cell.

Since configuration of the back contact heterojunction solar cell is substantially the same as the IBC solar cell shown inFIGS. 5 and 6, except that a plurality of emitter regions of the second conductive type formed of amorphous silicon and a plurality of back surface field regions of the first conductive type formed of amorphous silicon are positioned on a substrate of the first conductive type formed of crystalline silicon, a further description may be briefly made or may be entirely omitted.

Accordingly, the back surface of the substrate of the IBC solar cell or the back contact heterojunction solar cell is configured so that the first electrodes141aand the second electrodes142are alternately positioned thereon as shown inFIG. 7. The number of first electrodes141aand the number of second electrodes142shown inFIG. 7are simply one example. Other numbers may be used.

As shown inFIG. 7, all of the plurality of the first electrodes141aand the plurality of second electrodes142are positioned on the surface (for example, the back surface) of the substrate110. The plurality of front electrodes141aare separated from each other and extend in the same direction and the plurality of back electrodes142are separated from each other and extend in the same direction. Further, the front electrodes141aand the back electrodes142are alternately positioned on the back surface of the substrate110. Similar toFIG. 4, the solar cell1does not include an element for connecting all of the plurality of first electrodes141a, and an element for connecting all of the plurality of second electrodes.142, and thereby, all the first electrodes141aare electrically and physically separated from each other and all the second electrodes142are also electrically and physically separated from each other.

An operation of the solar cell1, for example, the back contact solar cell having the above-described structure (i.e., the IBC structure) is described below.

When light irradiated to the solar cell1is incident on the substrate110through the emitter region120(or120a), electrons and holes are generated in the substrate110by light energy produced based on the incident light. Because the surface of the substrate110is the textured surface, a light reflectance in the surface of the substrate110decreases and an amount of light incident on the substrate110increases. In addition, because a reflection loss of the light incident on the substrate110is reduced by the anti-reflection layer130, an amount of light incident on the substrate110further increases.

The electrons move to the n-type emitter region120(or120a) and the holes move to the p-type substrate110by the p-n junction between the substrate110and the emitter region120(or120a). The electrons moving to the n-type emitter region120(or120a) are collected by the front electrodes141and then move to the front electrode current collectors161electrically connected to the front electrodes141through the via holes181. The holes moving to the p-type substrate110are collected by the back electrodes151through the back surface field region171and then move to the back electrode current collectors162or move to the first electrodes141aor the second electrodes142.

As described above, the plurality of solar cells1of the solar cell module100are arranged in the matrix structure and are connected in series or parallel to one another

A serial connection structure of the plurality of solar cells1having the matrix structure according to the embodiment of the invention is described below with reference toFIG. 8.

FIG. 8shows the plurality of solar cells arranged in the structure of 4×7 matrix. Other matrix structures may be used for the solar cells.

When the solar cell1shown inFIG. 8is the MWT solar cell, a hole terminal11may be one of the front electrode current collector161and the back electrode current collector162, and an electron terminal12may be the other current collector. Alternatively, when the solar cell1shown inFIG. 8is the IBC solar cell or the back contact heterojunction solar cell, the hole terminal11may be one of the first electrode141aand the second electrode142, and the electron terminal12may be the other electrode.

As shown inFIG. 8, the plurality of solar cells1are arranged in the matrix structure, so that the hole terminals11and the electron terminals12of each solar cell1are positioned parallel to a side (first side) of a short axis of the solar cell module100(i.e., vertical to a side (second side) of a long axis of the solar cell module100).

The solar cell module100, in which the plurality of solar cells1are connected in series to one another, includes a plurality of first connectors21directly connected to the plurality of hole terminals11, a plurality of second connectors22directly connected to the plurality of electron terminals12, a plurality of third connectors23for directly connecting the first connectors21of one of the two adjacent solar cells1in a column direction to the second connectors22of the other of the two adjacent solar cells1in the column direction, a plurality of fourth connectors24for directly connecting the first connectors21of one of the two adjacent solar cells1in a row direction to the second connectors22of the other of the two adjacent solar cells1in the row direction, and a plurality of fifth connectors25which are directly connected to the hole terminals11of the solar cell1(for example, the solar cell1positioned on a first column of a first row) and to the electron terminals12of the solar cell1(for example, the solar cell1positioned on a last column of the first row), which are not connected to the electron terminals12or the hole terminals11of the solar cell1adjacent thereto.

In the embodiment of the invention, the first connectors21, the second connectors22, the third connectors23, the fourth connectors24, and the fifth connectors25have substantially the same length and the same width, respectively.

Further, the first to fifth connectors21to25are formed of the same material. The first to fifth connectors21to25are generally referred to as a ribbon and are formed of a thin metal plate band, i.e., a conductive tape which contains a conductive material and has a string shape. Examples of the conductive material include at least one selected from the group consisting of nickel (Ni), copper (Cu), silver (Ag), aluminum (Al), tin (Sn), zinc (Zn), indium (In), titanium (Ti), gold (Au), and a combination thereof. A separate adhesive may be used to attach the first to fifth connectors21to25to the corresponding components, and the adhesive may be applied to the first to fifth connectors21to25.

Each of the plurality of first connectors21is connected to the hole terminal11positioned on the back surface of the substrate of the solar cell1. A width of the first connector21is less than a width of the hole terminal11in an embodiment of the invention, but may be equal to or greater than the width of the hole terminal11in another embodiment of the invention. A length of the first connector21is greater than a length of the hole terminal11in an embodiment of the invention, but may be equal to or less than the length of the hole terminal11in another embodiment of the invention.

Each of the plurality of second connectors22is connected to the electron terminal12positioned on the back surface of the substrate of the solar cell1. A width of the second connector22is less than a width of the electron terminal12in an embodiment of the invention, but may be equal to or greater than the width of the electron terminal12in another embodiment of the invention. A length of the second connector22is greater than a length of the electron terminal12in an embodiment of the invention, but may be equal to or less than the length of the electron terminal12in another embodiment of the invention.

The plurality of first and second connectors21and22are positioned parallel to the side of the short axis of the solar cell module100, and thus are directly positioned on the hole terminals11and the electron terminals12, respectively and parallel to the hole terminals11and the electron terminals12.

Each of the plurality of third connectors23is connected to the first connectors21of one of the two adjacent solar cells1in the column direction and to the second connectors22of the other of the two adjacent solar cells1in the column direction.

Accordingly, the two adjacent solar cells1in the column direction are connected in series to each other using the third connector23.

The third connector23connects the hole terminals11of one of the two adjacent solar cells1in the column direction to the electron terminals12of the other of the two adjacent solar cells1in the column direction, thereby connecting the plurality of solar cells1arranged in the column direction in series to one another. Therefore, the plurality of third connectors23are alternately positioned on the left and right sides of each column of the solar cells.

In other words, the third connector23connected to the first and second solar cells1positioned adjacent to each other in the column direction is positioned on the same side of the first and second solar cells1, for example, the left or right side of the first and second solar cells1.

The plurality of third connectors23are positioned parallel to a side of the long axis of the solar cell module100, and thus are positioned vertical (or perpendicular) to the plurality of first and second connectors21and22.

Each of the plurality of fourth connectors24is positioned between the two adjacent solar cells1in the row direction. Hence, each fourth connector24is connected to the first connectors21of one of the two adjacent solar cells1in the row direction and to the second connectors22of the other of the two adjacent solar cells1in the row direction.

Accordingly, the two adjacent solar cells1in the row direction are connected in series to each other using the fourth connector24.

The fourth connector24connects the hole terminals11of one of the two adjacent solar cells1in the row direction to the electron terminals12of the other of the two adjacent solar cells1in the row direction, thereby connecting the two adjacent solar cells1in the row direction in series to each other. Therefore, the plurality of fourth connectors24are positioned parallel to the side of the long axis of the solar cell module100, and thus are positioned vertical (or perpendicular) to the plurality of first and second connectors21and22.

Because each fourth connector24is positioned between the first and second solar cells1positioned adjacent to each other in the row direction, the fourth connector24is positioned on the different sides of the first and second solar cells1. For example, the fourth connector24is positioned between the right side of the first solar cell1and the left side of the second solar cell1.

The third connector23connects the two adjacent solar cells1in the column direction to each other, and the fourth connector24connects the two adjacent solar cells1in the row direction to each other. Therefore, a length of the third connector23is greater than a length of the fourth connector24. For example, the length of the third connector23may be about two times the length of the fourth connector24.

The plurality of fifth connectors25are connected to the first connectors21of the first solar cell1(for example, the solar cell1positioned on the first row and the first column inFIG. 8) among the plurality of solar cells1connected in series to one another and are connected to the second connectors22of the last solar cell1(for example, the solar cell1positioned on the first row and the last column inFIG. 8). In this instance, the plurality of fifth connectors25are not connected to the second connectors22of the first solar cell1and are not connected to the first connectors21of the last solar cell1. Thus, the number of fifth connectors25is two.

At least one of the plurality of fifth connectors25is connected to a separate adhesive tape and is connected to an external device, for example, a junction box positioned under the solar cell module100.

Hence, the plurality of solar cells1having the matrix structure, which are connected in series to one another using the plurality of first to fourth connectors21to24, are connected to the external device using the fifth connectors25and thus output a desired amount of electric current.

InFIG. 8, the structures of the solar cells1arranged in the same row are the same as each other, and the structures of the solar cells1arranged in the different rows are different.

In addition, in the solar cells1positioned on the same row, shapes or arrangements of the first connectors21are equal to each other, and shapes or arrangements of the second connectors22are equal to each other, but, in the solar cells1positioned on the different rows, the shapes or arrangements of the first connectors21are different, and the shapes or arrangements of the second connectors22are different.

For example, as shown inFIG. 8, for the solar cells positioned in the odd-numbered rows, the first connectors21are protruded to the left sides of the solar cells1and the second connectors22are protruded to the right sides of the solar cells1, but for the solar cells positioned in the even-numbered rows, the first connectors21are protruded to the right sides of the solar cells1and the second connectors22are protruded to the left sides of the solar cells1.

As shown inFIG. 8, the third to fifth connectors23to25are positioned outside each solar cell1. A portion of the first connector21and a portion of the second connector22are positioned inside each solar cell1, and a remaining portion of the first connector21and a remaining portion of the second connector22are positioned outside each solar cell1and thus are connected to one of the third to fifth connectors23to25. In other words, the third to fifth connectors23to25are positioned outside of each solar cell1and are connected to the portion of the first connector21and the portion of the second connector22which are positioned outside each solar cell1.

Hence, a distance between the two adjacent solar cells1in the column direction decreases, and thus an area of a non-incident surface of (or a non-electricity generating area within) the solar cell module100decreases. Further, an area having a color different from the solar cells1decreases, and thus a good appearance or aesthetics of the solar cell module100is provided.

Because the third to fifth connectors23to25are not positioned on the solar cells1, the hole terminals11and the electron terminals12extend to an edge of the substrate of each solar cell1. Hence, a formation area of the hole terminals11and a formation area of the electron terminals12increase. As a result, the efficiency of the solar cells1and the efficiency of the solar cell module100are improved.

Various examples of a connection structure of the solar cells1having the matrix structure according to the embodiment of the invention are described below with reference toFIGS. 9 to 12.

Structures and components identical or equivalent to those illustrated inFIG. 8are designated with the same reference numerals inFIGS. 9 to 12, and a further description may be briefly made or may be entirely omitted.

Unlike the connection structure illustrated inFIG. 8, a connection structure illustrated inFIG. 9uses the third to fifth connectors23to25without the use of the first and second connectors21and22.

The plurality of hole terminals11and the plurality of electron terminals12are directly connected to the third to fifth connectors23to25, and not through the first and second connectors21and22. Thus, a portion of each of the third to fifth connectors23to25is positioned inside (or to overlap) the solar cell1, and a remaining portion (i.e., a portion of each of the third to fifth connectors23to25positioned between the solar cells1) is positioned outside (or to not overlap) the solar cell1.

The structure of each solar cell1shown inFIG. 8is different from the structure of each solar cell1shown inFIG. 9in a disposition shape of the hole terminals11and the electron terminals12.

As shown inFIG. 8, an end of the hole terminal11and an end of the electron terminal12are positioned on the same straight line or are aligned. Therefore, a distance between the adjacent surface of the solar cell1and the end of the hole terminal11is substantially equal to a distance between the adjacent surface of the solar cell1and the end of the electron terminal12.

However, as shown inFIG. 9, distances d11and d21between the adjacent surface of the solar cell1and the end of the hole terminal11are different from distances d12and d22between the adjacent surface of the solar cell1and the end of the electron terminal12.

More specifically, as shown inFIG. 9, the third connectors23are alternately positioned on the left and right sides of the column of the solar cells. Therefore, one of the hole terminal11and the electron terminal12connected to the third connector23positioned on the left side of the column of the solar cells is positioned closer to the side of the solar cell1adjacent to the third connector23than the other terminal. On the contrary, one of the electron terminal12and the hole terminal11connected to the third connector23positioned on the right side of the column of the solar cells is positioned closer to the side of the solar cell1adjacent to the third connector23than the other terminal.

Accordingly, one of the hole terminal11and the electron terminal12connected to the third connector23is positioned closer to one side of the solar cell1adjacent to the third connector23than the other terminal. Hence, the third connector23is connected to one of the hole terminal11and the electron terminal12that is disposed closer to the adjacent side of the solar cell1in a straight line without a bend. As a result, the attachment between the third connector23and the hole terminal11or the electron terminal12is easily and quickly carried out.

InFIG. 9, the two adjacent solar cells1in the row direction have the same structure and the solar cells1positioned on the different rows are arranged with the different structures.

For example, inFIG. 9, in the solar cells positioned on the odd-numbered rows, the hole terminals11are protruded to the left sides of the solar cells and the electron terminals12are protruded to the right sides of the solar cells1, and in the solar cells positioned on the even-numbered rows, the hole terminals11are protruded to the right sides of the solar cells and the electron terminals12are protruded to the left sides of the solar cells1. Thereby, in the plurality of solar cells1positioned on the same row, the terminals (11or12) adjacent to the left sides of the solar cells1may be the same terminal (for example, the hole terminals11), and the terminals (12or11) adjacent to the right sides of the solar cells1may be the same terminal (for example, the electron terminals12).

Hence, the fourth connector24for connecting the first and second solar cells1positioned adjacent to each other in the row direction is positioned between the first and second solar cells1and is connected to the different terminals (for example, the electron terminals12of further protruding to the right side of the first solar cell1and the hole terminals11further protruding to the left side of the second solar cell1) further protruding to the fourth connector24.

However, the two adjacent solar cells1in the column direction each have the different structure or arrangement. Namely, the structures of the two adjacent solar cells1in the column direction have a rotation relationship of 180°. Hence, in the plurality of solar cells1positioned on the different rows, the terminals (11or12) adjacent to the left sides of the solar cells1may be the different terminals, and the terminals (12or11) on the right sides adjacent to the right sides of the solar cells1may be the different terminals.

For example, as shown inFIG. 9, in the plurality of solar cells1positioned on the odd-numbered rows, the terminals adjacent to the left sides of the solar cells1are the hole terminals11, and the terminals adjacent to the right sides of the solar cells1are the electron terminals12. Further, in the plurality of solar cells1positioned on the even-numbered rows, the terminals adjacent to the left sides of the solar cells1are the electron terminals12, and the terminals adjacent to the right sides of the solar cells1are the hole terminals11.

In the structure of the solar cell module100illustrated inFIG. 9, the plurality of first and second connectors21and22connected to the plurality of hole terminals11and the plurality of electron terminals12are not necessary. Therefore, the manufacturing cost and manufacturing time of the solar cell module100are greatly reduced.

Further, because the distance between the adjacent solar cells1in the row direction as well as the column direction decreases, the better appearance or aesthetics of the solar cell module100is provided and the size of the solar cell module100is reduced.

In an example of the embodiment of the invention, similar to the structure ofFIG. 8, the plurality of first connectors21connected to the plurality of hole terminals11and the plurality of second connectors22connected to the plurality of electron terminals12may be positioned or provided, and the plurality of first and second connectors21and22may be connected to the plurality of third connectors23. On the other hand, unlike the structure ofFIG. 8, the plurality of first and second connectors21and22are positioned only inside (or to overlap) the corresponding solar cell and do not protrude to the outside of the corresponding solar cell. In this instance, because the third connectors23are connected to the first and second connectors21and22connected to the terminals11and12, an amount of carriers output to the third connectors23through the terminals11and12increases. Hence, the efficiency of the solar cell module is improved.

Another serial connection structure of the plurality of solar cells1having the matrix structure according to the embodiment of the invention is described below with reference toFIGS. 10 to 12.

When the plurality of solar cells1are connected in series to one another, a back structure of the back contact solar cell shown inFIGS. 10 to 12is different from the back structure of the back contact solar cell shown inFIGS. 4 and 7.

More specifically, the MWT back contact solar cell shown inFIG. 10further includes a first common current collector1611connected to the front electrode current collectors161and a second common current collector1621connected to the back electrode current collectors162, unlike the back contact solar cell shown inFIG. 4.

Hence, the front electrode current collectors161are connected to one another using the first common current collector1611, and the back electrode current collectors162are connected to one another using the second common current collector1621. In this instance, the expositing portions183for separating the back electrodes151from the front electrode current collectors161surround the front electrode current collectors161and the first common current collector1611connected to the front electrode current collectors161.

Further, the IBC back contact solar cell or the back contact heterojunction solar cell shown inFIG. 11further includes a first current collector161aconnected to the first electrodes141aand a second current collector162aconnected to the second electrodes142, unlike the back contact solar cell shown inFIG. 7.

InFIGS. 10 and 11, the first common current collector1611, the first current collector161a, the second common current collector1621, and the second current collector162arespectively extend in a direction crossing the respective front electrode current collectors161, the first electrodes141a, the back electrode current collectors162, and the second electrodes142and also extend parallel to the adjacent surface (for example, a top surface or a bottom surface in the solar cell ofFIG. 10 or 11). In this instance, the first common current collector1611and the second common current collector1621are positioned on the opposite sides of the solar cell1, and the first current collector161aand the second current collector162aare positioned on the opposite sides of the solar cell1.

The first and second common current collectors1611and1621are formed of the same material as the current collectors161and162, and the first and second current collectors161aand162aare formed of the same material as the first and second electrodes141aand142. In this instance, the current collectors161and162are formed along with the first and second common current collectors1611and1621at a corresponding location of the substrate of the solar cell1. Further, the first and second electrodes141aand142are formed along with the first and second current collectors161aand162aat a corresponding location of the substrate of the solar cell1.

The first and second common current collectors1611and1621are respectively connected to the current collectors161and162, and thus collect carriers collected by the current collectors161and162.

Further, the first and second current collectors161aand162aare respectively connected to the first and second electrodes141aand142, and thus collect carriers collected by the first and second electrodes141aand142.

When each solar cell1has the back structure illustrated inFIGS. 10 and 11, the plurality of solar cells1arranged in the matrix structure are connected in series to one another using only the third to fifth connectors23to25as shown inFIG. 12. As described above with reference toFIG. 9, a portion of each of the third to fifth connectors23to25is positioned inside (or to overlap) the solar cell1, and a remaining portion of each of the third to fifth connectors23to25positioned between the adjacent solar cells1is positioned outside (or to not overlap) the solar cell1.

Unlike the structure illustrated inFIG. 9, the third to fifth connectors23to25are not connected to the hole terminals11and the electron terminals12, and are connected to one of the first and second common current collectors1611and1621and one of the first and second current collectors161aand162a.

When each solar cell1shown inFIG. 12is the MWT solar cell, one (which collects holes) of the first and second common current collectors1611and1621is referred to as a hole current collector13a, and the other common current collector which collects electrons is referred to as an electron current collector13b.

Further, when each solar cell1shown inFIG. 12is the IBC solar cell or the back contact heterojunction solar cell, one (which collects holes) of the first and second current collectors161aand162ais referred to as the hole current collector13a, and the other current collector which collects electrons is referred to as the electron current collector13b.

Hence, electrons and holes collected by each solar cell1move and are output to the external device, such as the junction box, through the third to fifth connectors23to25connected to the hole current collector13aor the electron current collector13b.

Because a contact area between the third to fifth connectors23to25and the hole current collector13aor the electron current collector13bincreases as compared to the structure illustrated inFIG. 9, an amount of carriers output from the hole current collector13aor the electron current collector13bto the third to fifth connectors23to25increases.

Similar to the structure illustrated inFIG. 9, in the plurality of solar cells1of the matrix structure shown inFIG. 12, the solar cells1positioned on the same row have the same structure, and the two adjacent solar cells1in the column direction have the different structures. The two adjacent solar cells1in the column direction have a rotation relationship of 180°. Hence, the hole terminals11are adjacently positioned to the left side of each of the solar cells1positioned on the odd-numbered rows, and the electron terminals12are adjacently positioned to the right side thereof. Further, the hole terminals11are adjacently positioned to the right side of each of the solar cells1positioned on the even-numbered rows, and the electron terminals12are adjacently positioned to the left side thereof.

When the plurality of solar cells1having the above-described structure are connected in series to one another, the transparent member40, the upper and lower protective layers20aand20b, the plurality of solar cells1, and the back sheet30are disposed in a fixed order. Then, predetermined heat and pressure are applied to them to perform a laminating process. Hence, the solar cell module100is formed. More specifically, the upper and lower protective layers20aand20bare melted by the heat and thus are filled in a space between the components. Hence, the transparent member40, the upper protective layer20a, the plurality of solar cells1, the lower protective layer20b, and the back sheet30are attached to one another and form an integral body. Thus, the upper and lower protective layers20aand20bform one protective member through the laminating process, and the plurality of solar cells1are surrounded by the protective member and are protected from the external impact and moisture.

Next, the frame60is installed at the edge of the solar cell module100, thereby completing the solar cell module100. In this instance, the frame60is formed of a material, for example, aluminum coated with an insulating material that does not generate corrosion, deformation, etc., under influence of the external environment. The frame60has the structure in which the drainage process, the installation, and the execution are easily performed. The frame60may be omitted, if desired.

In an alternative example, the first to fifth connectors21to25shown inFIGS. 8 to 12may be formed of a conductive adhesive film.

The conductive adhesive film may include a resin and conductive particles distributed into the resin. A material of the resin is not particularly limited as long as it has the adhesive property. It is preferable, but not required, that a thermosetting resin is used for the resin so as to increase the adhesive reliability.

The thermosetting resin may use at least one selected among epoxy resin, phenoxy resin, acryl resin, polyimide resin, and polycarbonate resin.

The resin may further contain a predetermined material, for example, a known curing agent and a known curing accelerator other than (or in addition to) the thermosetting resin.

For example, the resin may contain a reforming material such as a silane-based coupling agent, a titanate-based coupling agent, and an aluminate-based coupling agent, so as to improve an adhesive strength between a conductive pattern part and the solar cells1. The resin may contain a dispersing agent such as calcium phosphate and calcium carbonate, so as to improve the dispersibility of the conductive particles. The resin may contain a rubber component such as acrylic rubber, silicon rubber, and urethane rubber, so as to control the modulus of elasticity of the conductive adhesive film.

A material of the conductive particles is not particularly limited as long as it has the conductivity. The conductive particles may contain at least one metal selected among copper (Cu), silver (Ag), gold (Au), iron (Fe), nickel (Ni), lead (Pb), zinc (Zn), cobalt (Co), titanium (Ti), and magnesium (Mg) as the main component. The conductive particles may be formed of only metal particles or of metal-coated resin particles. The conductive adhesive film having the above-described configuration may further include a peeling film.

It is preferable, but not required, that the conductive particles use the metal-coated resin particles, so as to mitigate a compressive stress of the conductive particles and improve the connection reliability of the conductive particles.

It is preferable, but not required, that the conductive particles have a diameter of about 2 μm to 30 μm, so as to improve the dispersibility of the conductive particles.

It is preferable, but not required, that a composition amount of the conductive particles distributed into the resin is about 0.5% to 20% based on the total volume of the conductive adhesive film in consideration of the connection reliability after the resin is cured. When the composition amount of the conductive particles is equal to or greater than about 0.5%, the current more smoothly flows because a physical contact between the conductive adhesive part and the front electrodes is more stably achieved. When the composition amount of the conductive particles is equal to or less than about 20%, the adhesive strength is stably maintained and the current more smoothly flows because a composition amount of the resin is normally maintained.

A solar cell module100aaccording to another example embodiment of the invention is described below with reference toFIGS. 13 to 15.

Structures and components identical or equivalent to those illustrated inFIGS. 1 to 12are designated with the same reference numerals in the solar cell module shown inFIGS. 13 to 15, and a further description may be briefly made or may be entirely omitted.

As shown inFIG. 13, the solar cell module100aaccording to the embodiment of the invention includes a plurality of solar cells1, upper and lower protective layers20aand20b1for protecting the solar cells1, a transparent member40positioned on the upper protective layer20a, a back sheet30positioned with the lower protective layer20b1, a pattern forming part50positioned under the back sheet30, and a frame60, similar to the solar cell module100shown inFIG. 1.

The solar cell module100afurther includes an insulating sheet70between the lower protective layer20b1and the back sheet30and a conductive pattern part51on the back sheet30.

The lower protective layer20b1has a plurality of openings201unlike the upper protective layer20a, and thus has a structure different from the upper protective layer20a.

The plurality of openings201are positioned at a location corresponding to hole terminals11and electron terminals12of each solar cell1. At least a portion of each hole terminal11and at least a portion of each electron terminal12are exposed through the openings201. A width of each opening201is equal to or less than widths of each hole terminal11and each electron terminal12. Alternatively, the width of each opening201may be greater than the widths thereof.

The insulating sheet70between the lower protective layer20b1and the pattern forming part50is formed of an insulating material and provides an electrical insulation between the lower protective layer20b1and the pattern forming part50. The insulating sheet70has a plurality of openings701. The plurality of openings701are positioned at a location corresponding to the plurality of openings201of the lower protective layer20b1. Thus, at least a portion of each hole terminal11and at least a portion of each electron terminal12are exposed through the openings701.

As shown inFIG. 14, a width D2of the opening701of the insulating sheet70is substantially equal to a width D1of the opening201of the lower protective layer20b1. However, the width D2and the width D1may be different from each other. For example, the width D2of the opening701of the insulating sheet70may be less or greater than the width D1of the opening201of the lower protective layer20b1.

The openings201and701have lengths and widths corresponding to lengths and widths of the hole terminals11and the electron terminals12opposite the openings201and701and thus have a stripe shape elongated (or extending) in a fixed direction.

Alternatively, at least one of the openings201and701may have the structure in which a plurality of holes are arranged along the extending direction of the hole terminals11and the electron terminals12. Each hole may have various cross-sectional shapes such as a circle, a polygon and an oval, and a distance between the holes may be uniform or non-uniform. Further, the size and the number of holes may be determined depending on the length and the width of the hole terminals11and the electron terminals12. In this instance, the hole terminals11and the electron terminals12may be exposed through the holes.

As shown inFIGS. 13 and 14, the back sheet30and the conductive pattern part51on the back sheet30form the pattern forming part50.

The conductive pattern part51is positioned on the back sheet30. In the embodiment of the invention, the conductive pattern part51is formed of copper (Cu). Other conductive materials may be used. For example, the conductive pattern part51may be formed of silver (Ag), aluminum (Al), or nickel (Ni), etc.

Another conductive layer may be formed on the conductive pattern part51by coating a conductive material on the conductive pattern part51, so as to improve the conductivity of the conductive pattern part51and contact characteristic between the conductive pattern part51and the solar cells1. The conductive pattern part51and the conductive layer may be formed of the same conductive material or different conductive materials each having different characteristic. When the conductive pattern part51and the conductive layer are formed of the different conductive materials, the conductivity of the conductive layer may be more excellent (or improved) than the conductivity of the conductive pattern part51alone. In this instance, the conductive pattern part51may be formed of Al or Ni, etc., and the conductive layer on the conductive pattern part51may be formed of Au or Ag, etc.

As shown inFIG. 15, the conductive pattern part51includes a plurality of first patterns511connected to the hole terminals11and the electron terminals12of the two adjacent solar cells1in a column direction, a plurality of second patterns512connected to the hole terminals11and the electron terminals12of the two adjacent solar cells1in a row direction, and a plurality of third patterns513connected to the hole terminals11or the electron terminals12.

Because the conductive pattern part51is positioned on the back sheet30formed of the insulating material, the back sheet30is exposed to a portion of the first to third patterns511to513, on which the conductive pattern part51is not positioned.

The first to third patterns511to513respectively include bodies51a,52a, and53a, which elongate to (or extends on) one surface (for example, the side of a long axis) of the back sheet30or in the column direction of the solar cell module100a, and a plurality of branches51b,52b, and53bwhich extend from the bodies51a,52a, and53ato another surface (for example, the side of a short axis) of the back sheet30or in the row direction of the solar cell module100a.

As shown inFIG. 15, the plurality of branches51b,52b, and53bof the first to third patterns511to513extend from the bodies51a,52a, and53aand thus have a comb teeth structure. The bodies51a,52a, and53aof the first to third patterns511to513elongate in (or extends in) a direction (for example, a vertical direction) crossing the hole terminals11and the electron terminals12.

The first to third patterns511to513are separated from one another and are electrically insulated from one another.

Each of the branches51b,52b, and53bis divided into a first branch connected to the hole terminal11and a second branch connected to the electron terminal12.

In the first to third patterns511to513, widths w1of the first branches51b,52b, and53bconnected to the hole terminals11are substantially equal to one another, and widths w2of the second branches51b,52b, and53bconnected to the electron terminals12are substantially equal to one another. In the embodiment of the invention, the widths w1of the first branches51b,52b, and53bconnected to the hole terminals11are different from the widths w2of the second branches51b,52b, and53bconnected to the electron terminals12. However, the width w1may be substantially equal to the width w2.

The widths w1and w2of the branches51b,52b, and53bmay be determined depending on the number of hole terminals11and the number of electron terminals12. For example, as the number of terminals11and12increases, an amount of current flowing through the branches51b,52b, and53bdecreases. Thus, as an amount of current flowing through the branches51b,52b, and53b(i.e., an amount of load) decreases, the widths w1and w2of the branches51b,52b, and53bdecrease. In the embodiment of the invention, because the four hole terminals11and the three electron terminals12are positioned (or exist), the widths w2of the second branches51b,52b, and53bconnected to the electron terminals12are greater than the widths w1of the first branches51b,52b, and53bconnected to the hole terminals11.

In an alternative example, when the number of hole terminals11is equal to the number of electron terminals12, the widths w1of the first branches51b,52b, and53bconnected to the hole terminals11may be substantially equal to the widths w2of the second branches51b,52b, and53bconnected to the electron terminals12.

Lengths L1to L3of the branches51b,52b, and53bof the first to third patterns511to513are determined depending on lengths of the hole terminal11and the electron terminal12. In the embodiment of the invention, the lengths L1to L3of the branches51b,52b, and53bare substantially equal to one another.

The plurality of first patterns511connect the hole terminals11of one of the plurality of solar cells1arranged in the column direction to the electron terminals12of another solar cell1adjacent to (i.e., in front of or behind) the one solar cell1.

The plurality of first patterns511are alternately positioned on the left and right sides of the solar cells1positioned on the same column.

More specifically, the first pattern511positioned on the left side of the two adjacent solar cells1in the column direction is connected to the hole terminals11or the electron terminals12of one of the two adjacent solar cells1, and the electron terminals12or the hole terminals11of the other of the two adjacent solar cells1. The first pattern511positioned on the right side of the two adjacent solar cells1in the column direction is connected to the electron terminals12or the hole terminals11of one of the two adjacent solar cells1, and is connected to the hole terminals11or the electron terminals12of the solar cell1adjacent to (i.e., in front of or behind) the one solar cell1.

Accordingly, the solar cells1positioned on the same column are electrically connected in series to one another using the plurality of first patterns511.

The plurality of second patterns512are connected to the hole terminals11and the electron terminals12(not connected to the two adjacent solar cells1in the column direction) of the two solar cells1positioned on a first row of two adjacent rows of the solar cells1or the two solar cells1positioned on a last row thereof.

The solar cells1positioned on the different columns are electrically connected in series to one another using the plurality of second patterns512.

The plurality of third patterns513are connected to the hole terminals11or the electron terminals12of the solar cell1(for example, the solar cell1positioned on a first row and a first column), which is not connected to the hole terminals11or the electron terminals12of the solar cell1adjacent thereto, among the solar cells1positioned on the first column; and are connected to the hole terminals11or the electron terminals12of the solar cell1(for example, the solar cell1positioned on the first row and a last column), which is not connected to the electron terminals12or the hole terminals11of the solar cell1adjacent thereto, among the solar cells1positioned on the last column.

Thus, the number of third patterns513is two.

The bodies53aof the plurality of third patterns513are connected to a conductive tape and are connected to an external device, for example, a junction box positioned under the solar cell module100a.

The plurality of solar cells1having the matrix structure, which are connected in series to one another using the plurality of first and second patterns511and512, are connected to the external device using the third patterns513and thus output a desired amount of electric current.

As shown inFIG. 14, conductive adhesive parts54are positioned on the openings701of the insulating sheet70. The conductive adhesive parts54are filled in the openings201and701because of heat generated when the lamination process is performed. Hence, the terminals11and12exposed through the openings201and701contact the conductive pattern part51by the conductive adhesive parts54positioned in the openings201and701.

The conductive adhesive part54may be formed of the above-described conductive adhesive film, a conductive paste, a conductive epoxy, etc.

The branches51b,52b, and53bof the first to third patterns511to513of the conductive pattern part51on the back sheet30are connected to the hole terminals11and the electron terminals12exposed through the openings201and701. Hence, the solar cells1having the matrix structure are electrically connected in series to one another, and thus carriers output from the solar cells1are output to the external device. As a result, an amount of current flows therein.

In the embodiment of the invention, the plurality of solar cells1are positioned at a corresponding location of the conductive pattern part51including the first to third patterns511to513, and then heat and pressure are applied to the plurality of solar cells1. Hence, the plurality of solar cells1are electrically connected to the conductive pattern part51. As a result, the plurality of solar cells1are automatically connected in series to one another.

In other words, the insulating sheet70is positioned on the conductive pattern part51, and the conductive adhesive part54is positioned at a location corresponding to a formation location of the insulating sheet70. Then, the lower protective layer20b1is positioned on the insulating sheet70. Next, the plurality of solar cells1are positioned at a uniform distance therebetween, the upper protective layer20ais arranged on the solar cells1, and the transparent member40is positioned on the upper protective layer20a. Next, the lamination process is performed to form an integral body of the above components.

Further, the conductive adhesive part54is filled in the openings201and701because of the heat generated when the lamination process is performed. The hole terminals11and the electron terminals12of each solar cell1are connected to the conductive pattern part51of the pattern forming part50by the conductive adhesive part54.

Thus, instead of a process in which a conductive film is cut and then the conductive tape (i.e., the plurality of connectors21to25) is attached to the hole terminals11and the electron terminals12of the plurality of solar cells1, the electrical connection of the plurality of solar cells1is automatically completed using the conductive pattern part51having a desired pattern when the lamination process is completed. As a result, manufacturing time of the solar cell module100ais reduced, and thus the production efficiency of the solar cell module100ais improved.

FIGS. 13 to 15illustrate that the conductive pattern part51and the back sheet30are manufactured to form an integral body, i.e., the pattern forming part50. In this instance, the conductive pattern part51is formed by forming a conductive layer formed of copper (Cu), etc. on the back sheet30, patterning the conductive layer in a desired shape using a dry etching method or a wet etching method, etc., and forming the conductive layer having the desired shape on the back sheet30.

Alternatively, the conductive pattern part51and the back sheet30may be manufactured as separate parts. In this instance, the conductive pattern part51, which is patterned in a desired shape to have a sheet form, is positioned on the back sheet30of a sheet form as the separate part. Further, a formation location of the conductive pattern part51is determined in consideration of formation locations of the openings201of the lower protective layer20b1and the openings701of the insulating sheet70. Hence, when the conductive pattern part51and the back sheet30are manufactured as the separate parts, only the back sheet30serves as a back sheet.

In an alternative example, the insulating sheet70and the pattern forming part50may be manufactured to form an integral body. In this instance, the pattern forming part50may include the insulating sheet70, the conductive pattern part51, and the back sheet30.

FIG. 14shows the conductive adhesive part54positioned on the insulating sheet70. However, the conductive adhesive part54may be positioned on the lower protective layer20b1or on the insulating sheet70and the conductive pattern part51. When the conductive adhesive part54is positioned on the lower protective layer20b1, the conductive adhesive part54may be positioned on the openings201of the lower protective layer20b1. When the conductive adhesive part54is positioned on the conductive pattern part51, the conductive adhesive part54may be positioned at a location corresponding to the openings701of the insulating sheet70.

As shown inFIG. 15, each of the branches51b,52b, and53bhas an angular edge. However, in other embodiments, the edge of each of the branches51b,52b, and53bmay have a curved shape. When the edge of each of the branches51b,52b, and53bhas the angular shape, carriers may concentrate in an angular portion (i.e., the angular edge) of each of the branches51b,52b, and53b. Hence, the carriers may not be uniformly distributed in each of the branches51b,52b, and53b, and the problem such as an arc may be caused. However, when the edge of each of the branches51b,52b, and53bhas the curved shape, the carriers may be uniformly distributed in each of the branches51b,52b, and53b. Hence, the electrical problem such as the arc may be prevented or reduced.

The above-described method illustrated inFIGS. 13 to 15, in which the conductive pattern part51of the desired shape is formed on the back sheet30at a location corresponding to the openings201of the lower protective layer20b1and the openings701of the insulating sheet70, and the plurality of solar cells1are electrically connected to one another in the lamination process, may be applied to the configuration ofFIG. 8.

Namely, the third to fifth connectors23to35shown inFIG. 8are formed on the back sheet30as the conductive pattern part51, and then the openings of the insulating sheet70and the lower protective layer20b1are formed at the location corresponding to the formation location of the third to fifth connectors23to35.

In this instance, since the configuration ofFIG. 8is substantially the same as the embodiment illustrated inFIGS. 13 to 15except the shape and the formation location of the conductive pattern part51and the shape and the formation location of the openings701and201of the insulating sheet70and the lower protective layer20b1, a further description will not repeated.