Abstract:
A method for manufacturing a solar cell module includes forming a first electrode on a first surface of a substrate; forming a semiconductor layer on the first electrode; forming a second electrode on the semiconductor layer; inverting the substrate with the first electrode, semiconductor layer and second electrode formed thereon, and then, positioning the inverted substrate on a plurality of supports; patterning the second electrode and the semiconductor layer while the inverted substrate is on the supports by irradiating a laser on a second surface of the substrate to form a plurality of solar cells, wherein the second surface of the substrate is opposite the first surface of the substrate; identifying defective solar cells by using the supports; and repairing the defective solar cells by using the supports.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to Korean Patent Application No. 10-2010-0118724 filed in the Korean Intellectual Property Office on Nov. 26, 2010, the disclosure of which is incorporated by reference herein in its entirety. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present invention relates to a laser apparatus and a method for manufacturing a solar cell module using the same. 
         [0004]    2. Discussion of the Related Art 
         [0005]    A solar cell is a photoelectric conversion device that transforms solar energy into electrical energy, and has been drawing much attention as an infinite, yet pollution-free next-generation energy resource. 
         [0006]    A solar cell is basically a diode configured of a PN junction, except that the solar cell&#39;s diode is exposed to light which yields a photocurrent in addition to the diode current. Solar cells may be classified according to a material they use as a light absorbing layer. 
         [0007]    For example, a solar cell that uses silicon as the light absorbing layer may be classified as a crystalline silicon solar cell or a thin film solar cell. A crystalline silicon solar cell may be classified according to its crystallinity (e.g., single crystal or polycrystalline). A thin film solar cell may be classified according to its photovoltaic material (e.g., crystalline or amorphous). 
         [0008]    Classes of solar cells belonging to the group of thin film solar cells may include a copper indium gallium selenide (CIGS) solar cell, a cadmium telluride (CdTe) solar cell, a III-V group semiconductor solar cell, a dye-sensitized solar cell, and an organic solar cell. 
         [0009]    In a solar cell module manufacturing process, a plurality of solar cells is patterned to be connected in series to form a desired voltage of the module. The patterning involves a laser patterning process, and then, an inspection process is performed in which inter-cell insulation resistance characteristics are measured to determine whether or not a defective cell is present. Subsequently, defective cells, e.g., those having poor insulation characteristics, are repaired. 
         [0010]    As can be gleaned, the steps involved in the manufacture of a solar cell module can be time consuming. Therefore, there is a need to quicken the solar cell module manufacturing process. 
       SUMMARY 
       [0011]    An exemplary embodiment of the present invention provides a method for manufacturing a solar cell module, including: forming a first electrode on a first surface of a substrate; forming a semiconductor layer on the first electrode; forming a second electrode on the semiconductor layer; inverting the substrate with the first electrode, semiconductor layer and second electrode formed thereon, and then, positioning the inverted substrate on a plurality of supports; patterning the second electrode and the semiconductor layer while the inverted substrate is on the supports by irradiating a laser on a second surface of the substrate to form a plurality of solar cells, wherein the second surface of the substrate is opposite the first surface of the substrate; identifying defective solar cells by using the supports; and repairing the defective solar cells by using the supports. 
         [0012]    The supports may be included on a supporting plate, and wherein a first support includes first and second vertical supporting members vertically extending from the supporting plate and a horizontal supporting member having a first end connected to the first vertical supporting member and a second end connected to the second vertical support member. 
         [0013]    The first support may be in contact with a surface of the second electrode of a solar cell. 
         [0014]    The defective solar cells may be identified by measuring a resistance of each solar cell. 
         [0015]    The resistance measurement of a solar cell is made by using the support in contact with that solar cell and the support in contact with an adjacent solar cell. 
         [0016]    A solar cell is defective if its measured resistance is 500Ω or less. The defective cells may be repaired by applying a current or voltage to the supports contacting the defective cells. 
         [0017]    The defective cells may be repaired by applying a voltage of 3V to 12V to the supports contacting the defective cells. 
         [0018]    The defective cells may be repaired by applying a current of 0.05 A to 0.3 A to the supports contacting the defective cells for 1 second to 5 seconds. 
         [0019]    The method for manufacturing a solar cell module may further include forming a first groove in the first electrode by patterning the first electrode after forming the first electrode. 
         [0020]    The method for manufacturing a solar cell module may further include forming a second groove in the semiconductor layer by patterning the semiconductor layer after forming the semiconductor layer. 
         [0021]    The supports on the supporting plate may be configured such that a first support includes first and second vertical supporting members vertically extending from the supporting plate and first and second horizontal supporting members, each horizontal supporting member having a first end connected to the first vertical supporting member and a second end connected to the second vertical supporting member, and a groove may be disposed between the first and second horizontal supporting members. 
         [0022]    The identification of the defective solar cells may be performed immediately after the patterning of the second electrode and the semiconductor layer. The defective solar cells may be repaired immediately after they are identified. 
         [0023]    An exemplary embodiment of the present invention provides a laser apparatus, including: a laser generator; and an inspecting and repairing unit, wherein the inspecting and repairing unit includes a supporting plate, and a plurality of supports disposed on the supporting plate, wherein a support includes first and second vertical supporting members vertically extending from the supporting plate and a horizontal supporting member connecting the vertical supporting members, and wherein the plurality of supports receive a current or voltage through the supporting plate. 
         [0024]    The horizontal supporting member may include a first horizontal supporting member and a second horizontal supporting member with a space formed therebetween. 
         [0025]    The laser apparatus may include a space between the laser generator and the supports, the space being large enough to accommodate a solar cell module therebetween. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  is a layout showing a solar cell module according to an exemplary embodiment of the present invention; 
           [0027]      FIG. 2  is a cross-sectional view taken along line II-II of  FIG. 1 ; 
           [0028]      FIGS. 3 to 6  are diagrams sequentially showing a method for manufacturing a solar cell module according to an exemplary embodiment of the present invention; 
           [0029]      FIG. 7  is a diagram showing a support structure according to an exemplary embodiment of the present invention; and 
           [0030]      FIG. 8  is a diagram showing a support structure according to an exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0031]    Exemplary embodiments of the present invention will be described more fully hereinafter with reference to the accompanying drawings. 
         [0032]    However, the present invention may be embodied in various different ways and should not be construed as limited to the exemplary embodiments described herein. 
         [0033]    In the drawings, the shapes and sizes of elements may be exaggerated for clarity. 
         [0034]    It will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. 
         [0035]    Like reference numerals may designate like elements throughout the specification and drawings. 
         [0036]      FIG. 1  is a layout showing a solar cell module according to an exemplary embodiment of the present invention and  FIG. 2  is a cross-sectional view taken along line II-II of  FIG. 1 . 
         [0037]    Referring to  FIGS. 1 and 2 , a solar cell module  1000  is configured to include a plurality of solar cells  200 . Each cell  200  is configured to include a first electrode  110 , a second electrode  150 , and a semiconductor layer  140  formed between the first electrode  110  and the second electrode  150 . In the solar cell module  1000 , the second electrode  150  and the first electrode  110  in adjacent solar cells  200  are connected are connected to each other. 
         [0038]    The first electrode  110  is formed on a substrate  100  composed of glass or plastic and a first groove  115  penetrating through the first electrode  110  is formed on the first electrode  110 . 
         [0039]    The first electrode  110  may be made of a transparent electrode containing material such as SnO2, ZnO:Al, ZnO:B, indium tin oxide (ITO), indium zinc oxide (IZO), or the like. 
         [0040]    The semiconductor layer  140  filled in the first groove  115  is formed on the first electrode  110  and a second groove  145  penetrating through the semiconductor layer  140  is formed thereon. 
         [0041]    A P layer  120  having a p-type (positive type) impurity and an N-layer  130  having an n-type (negative type) impurity are sequentially stacked in the semiconductor layer  140 . 
         [0042]    The P layer  120  may be made of any one of a boron doped amorphous silicon (a-Si:H), an amorphous silicon carbide (a-SiC:H), and a fine crystalline silicon (mc-Si:H). The N layer  130  may be made of an amorphous silicon (a-Si:H) or a fine crystalline silicon (mc-Si:H). In this case, an I (intrinsic) layer made of an amorphous material may be further provided between the P layer  120  and the N layer  130 . 
         [0043]    In addition, the P layer  120  may be made of CuInSe2(CIS) or CuInGaSe2(CIGS) and the N layer  130  may be made of CdS. 
         [0044]    According to an exemplary embodiment of the present invention, the semiconductor layer  140  may include a stacked structure in which a unit configured of the P layer, the I layer, and the N layer is repeated twice or more. Silicon oxide or zinc oxide may be included between the units. 
         [0045]    The second electrode  150  filling the second groove  145  is formed on the semiconductor layer  140  and a third groove  155  penetrating through the second electrode  150  and the semiconductor layer  140  is formed thereon. 
         [0046]    The second electrode  150  is made of a low resistance metal such as silver (Ag). 
         [0047]    The first groove  115  serves to insulate the first electrode  110  and the third groove  155  serves to insulate the adjacent solar cells  200  in the solar cell module  1000  having a plurality of solar cells  200 . The second electrode  150  and the first electrode  110  of the adjacent cells  200  are electrically connected to each other through the second groove  145 . 
         [0048]      FIGS. 3 to 6  are diagrams sequentially showing a method for manufacturing a solar cell module according to an exemplary embodiment of the present invention. 
         [0049]    Referring to  FIGS. 3 to 6 , the first electrode  110  is stacked on the substrate  100  by using a sputtering method, or the like. Further, the first groove  115  is formed by patterning the first electrode  110  using a laser scribing method or a mechanical scribing method. 
         [0050]    Then, the semiconductor layer  140  to fill the first groove  115  is formed on the first electrode  110 . Further, the second groove  145  is formed by patterning the semiconductor layer  140  using a laser scribing method or a mechanical scribing method. 
         [0051]    Then, the second electrode  150  to fill the second groove  145  is formed on the semiconductor layer  140 . The third groove  155  is formed by patterning the second electrode  150  and the semiconductor layer  140  by using a laser scribing method, thereby forming the plurality of cells  200 . 
         [0052]    The formation of the third groove  155  will now be described in more detail. For example, after the second electrode  150  is formed on the semiconductor layer  140  as shown  FIG. 5 , the resultant structure is inverted as shown in  FIG. 6 , and then, positioned on a support  450  supporting the resultant structure to prevent the structure from sagging. In this arrangement, particles may be easily removed when a laser patterning is performed. Then, a laser beam from a laser generator  300  on the top portion of the substrate  100  is emitted to the substrate  100 , thereby forming the third groove  155 . 
         [0053]    In this case, the first groove  115 , the second groove  145  and the third groove  155  may each be formed by the same laser scribing. 
         [0054]    The support  450  is formed on a supporting plate  400  and contacts the second electrode  150  of each cell  200 . 
         [0055]    After the third groove  155  is formed by performing the laser patterning, the resistance of each cell  200  is measured by using the support  450  that is in contact with the second electrode  150  of each cell  200  to identify defective cells. The defective cells are repaired by applying a voltage or current to the defective cells. 
         [0056]    The resistance is measured separately to the second electrode  150  through the supports  450 . In this case, it is determined that defective cells are present when the measured resistance is 500Ω or less. 
         [0057]    The repair of the defective cells is performed by burning or oxidizing metal components, which can degrade resistance characteristics, from the cells. This is done by applying a voltage of 3V to 12V to the supports  450  that are in contact with the defective cells or a current of 0.05 A to 0.3 A thereto for 1 second to 5 seconds. 
         [0058]    In this configuration, the laser generating apparatus  300 , the support  450 , and the supporting plate  400  are integrally formed. 
         [0059]    As set forth above, the support  450  can prevent the inverted substrate structure from sagging, measure each cell  200  for defects, and repair the defective cells, such that there is no need for separate inspection equipment, repair equipment, and/or substrate carrying equipment. In addition, an exemplary embodiment of the present invention can perform the inspection process and the repair process immediately after performing the laser patterning process, thereby shortening the time it takes to manufacture a solar cell module. 
         [0060]      FIG. 7  is a diagram showing a support structure according to an exemplary embodiment of the present invention. 
         [0061]    Referring to  FIG. 7 , the plurality of supports  450  are formed on the supporting plate  400 . An individual support  450  includes vertical supporting members  451  vertically extending from the supporting plate  400  and a horizontal supporting member  452  extended horizontally and connected to the vertical supporting members  451  at each end of the member  452 . The structure of the support  450  surface-contacts the second electrode  150  of each cell  200  along the horizontal supporting member  452 , thereby preventing the sagging of the inverted substrate structure. In addition, the support  450  has conductivity and is made of a material that does not scratch the surface-contacted second electrode  150 . 
         [0062]      FIG. 8  is a diagram showing a support structure according to an exemplary embodiment of the present invention. 
         [0063]    Referring to  FIG. 8 , the structure of the support shown in  FIG. 8  is similar to the structure of the support shown in  FIG. 7 , but has a difference in that the horizontal supporting member includes a first horizontal supporting member  452   a  and a second horizontal supporting member  452   b  with a groove formed therebetween. 
         [0064]    While the present invention has been described in detail with reference to the exemplary embodiments, those skilled in the art will appreciate that various modifications and substitutions can be made thereto without departing from the spirit and scope of the present invention as set forth in the appended claims.