JP2019054167A - Photoelectric conversion module - Google Patents

Abstract

To provide a photoelectric conversion module capable of balancing both a problem of power loss caused by an electric resistance value of a transparent electrode layer and a problem of short-circuit current reduction caused by light shielding due to a grid electrode.SOLUTION: A photoelectric conversion module comprises a photoelectric conversion cell 12 and grid electrodes 31 provided side by side in a first direction in the photoelectric conversion cell and extending in a second direction crossing the first direction. The photoelectric conversion cell 12 includes a first electrode layer, a second electrode layer, and a photoelectric conversion layer between the first electrode layer and the second electrode layer. The grid electrode 31 includes a plurality of main grid electrodes 31a and sub-grid electrodes 31b provided between the main grid electrodes 31a adjacent to each other. The length of the sub-grid electrode 31b along the second direction is shorter than the length of the main grid electrode 31a along the second direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a photoelectric conversion module having a grid electrode.

  A photoelectric conversion module such as a solar battery module including a plurality of photoelectric conversion cells is known (Patent Document 1 below). In the integrated thin film photoelectric conversion module described in Patent Document 1, the photoelectric conversion cell includes a transparent electrode layer positioned on the light receiving surface, a back electrode layer positioned on the surface opposite to the light receiving surface, and a transparent electrode. A photoelectric conversion layer between the layer and the back electrode layer.

  The electric resistance value of the transparent electrode layer is generally higher than the electric resistance value of an opaque electrode layer made of metal. Therefore, when current generated by photoelectric conversion flows through the transparent electrode layer, power loss due to the electrical resistance value of the transparent electrode layer occurs. In order to reduce power loss in the transparent electrode layer, a grid electrode (collecting electrode) made of a thin line metal may be provided on the transparent electrode layer.

JP2011-103425A

  In the photoelectric conversion module described in Patent Document 1, the current path flowing through the transparent electrode layer is shortened by collecting the current flowing through the transparent electrode layer at the grid electrode. Therefore, power loss due to the electrical resistance value of the transparent electrode layer can be reduced. However, since the grid electrode is generally non-transparent, it blocks light incident on the photoelectric conversion layer. Therefore, the short circuit current (Isc) generated in the photoelectric conversion cell is reduced by the decrease in the light reaching the photoelectric conversion layer.

  Therefore, it is desirable to balance both the problem of power loss due to the electrical resistance value of the transparent electrode layer and the problem of reducing short-circuit current due to light shielding by the grid electrode.

  A photoelectric conversion module according to an aspect includes a photoelectric conversion cell including a first electrode layer, a second electrode layer, a photoelectric conversion layer between the first electrode layer and the second electrode layer, and the photoelectric conversion module. And a grid electrode that is provided side by side in the first direction in the conversion cell and extends in a second direction that intersects the first direction. The grid electrode includes a plurality of main grid electrodes and the second direction. A subgrid electrode having a length shorter than the length of the main grid electrode, and the subgrid electrode is provided between the main grid electrodes adjacent to each other.

  According to the said aspect, reduction of the short circuit current resulting from the shielding of the light by a grid electrode can be suppressed, suppressing the loss of the electric power resulting from the electrical resistance value of a transparent electrode layer.

It is a typical top view of the photoelectric conversion module concerning a 1st embodiment. It is a typical top view of the photoelectric conversion module in the area | region 2R of FIG. FIG. 3 is a schematic cross-sectional view of the photoelectric conversion module taken along line 3A-3A in FIG. 2. It is a typical perspective view of the photoelectric conversion module in the area | region 4R of FIG. It is typical sectional drawing of the photoelectric conversion module along the 5A-5A line | wire of FIG. It is a typical top view of the photoelectric conversion module in the area | region 6R of FIG. It is a typical sectional view of a photoelectric conversion module concerning a 2nd embodiment. It is a typical sectional view of a photoelectric conversion module concerning a 3rd embodiment. It is a typical sectional view of a photoelectric conversion module concerning a 4th embodiment. It is a schematic top view of the connection part of the 1st grid electrode and 2nd grid electrode which concern on a 1st modification. It is a schematic top view of the connection part of the 1st grid electrode and 2nd grid electrode which concern on a 2nd modification. It is a schematic top view of the connection part of the 1st grid electrode and 2nd grid electrode which concern on a 3rd modification. It is typical sectional drawing which shows the cell formation process in the manufacturing method of a photoelectric conversion module. It is a schematic diagram which shows the 1st grid formation process which forms a 1st grid electrode. It is a schematic diagram which shows the 2nd grid formation process which forms a 2nd grid electrode. It is a schematic diagram which shows one step of the process of forming wiring. It is a schematic diagram which shows the step following FIG. It is a schematic diagram which shows the process of excising a part of photoelectric conversion module.

  Hereinafter, embodiments will be described with reference to the drawings. In the following drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like may differ from actual ones.

(First embodiment)
FIG. 1 is a schematic top view of the photoelectric conversion module according to the first embodiment. FIG. 2 is a schematic top view of the photoelectric conversion module in the region 2R of FIG. FIG. 3 is a schematic cross-sectional view of the photoelectric conversion module taken along line 3A-3A in FIG. FIG. 4 is a schematic perspective view of the photoelectric conversion module in the region 4R of FIG. FIG. 5 is a schematic cross-sectional view of the photoelectric conversion module taken along line 5A-5A in FIG. FIG. 6 is a schematic top view of the photoelectric conversion module in the region 6R of FIG.

  In FIGS. 2 and 6, for convenience, a layer below a second electrode layer 24 described later is illustrated in a perspective manner. Further, in FIG. 4, for the sake of convenience, the second electrode layer 24 described later is not drawn for easy understanding of the structure of the photoelectric conversion cell.

  The photoelectric conversion module 10 according to the present embodiment may be an integrated thin film photoelectric conversion module including a plurality of photoelectric conversion cells 12 integrated on a substrate 20. Preferably, the photoelectric conversion module 10 is a solar cell module that converts light energy into electrical energy. The substrate 20 may be made of, for example, glass, ceramics, resin, metal, or the like.

  The photoelectric conversion cell 12 may have a substantially band shape when viewed from a direction orthogonal to the main surface of the substrate 20. Each photoelectric conversion cell 12 may extend long in the first direction (Y direction in the figure). The plurality of photoelectric conversion cells 12 are arranged in a second direction (X direction in the figure) intersecting the first direction. Adjacent photoelectric conversion cells 12 may be separated from each other by divided parts P1, P2, and P3 extending in the first direction.

  Each photoelectric conversion cell 12 may include at least a first electrode layer 22, a second electrode layer 24, and a photoelectric conversion layer 26. The photoelectric conversion layer 26 is provided between the first electrode layer 22 and the second electrode layer 24. The first electrode layer 22 is provided between the photoelectric conversion layer 26 and the substrate 20. The second electrode layer 24 is located on the side opposite to the substrate 20 with respect to the photoelectric conversion layer 26.

  In the present embodiment, the second electrode layer 24 may be composed of a transparent electrode layer. When the second electrode layer 24 is constituted by a transparent electrode layer, light that enters or exits the photoelectric conversion layer 26 passes through the second electrode layer 24.

  When the 2nd electrode layer 24 is comprised with a transparent electrode layer, the 1st electrode layer 22 may be comprised by the opaque electrode layer, and may be comprised by the transparent electrode layer. In an example of a CIS-based photoelectric conversion module, the first electrode layer 22 is preferably formed of a metal such as molybdenum, titanium, or chromium from the viewpoint of corrosion resistance against a group VI element.

  In the present embodiment, as a preferred example, the second electrode layer 24 is formed of an n-type semiconductor, more specifically, an n-type conductivity, a wide band gap, and a relatively low resistance material. The The second electrode layer 24 may be made of, for example, zinc oxide (ZnO) added with a group III element or indium tin oxide (ITO). In this case, the second electrode layer 24 can also function as an n-type semiconductor and a transparent electrode layer.

  The photoelectric conversion layer 26 may include, for example, a p-type semiconductor. In an example of the CIS-based photoelectric conversion module, the photoelectric conversion layer 26 includes a group I element (Cu, Ag, Au, etc.), a group III element (Al, Ga, In, etc.) and a group VI element (O, S, Se, etc.). Te) or the like. The photoelectric conversion layer 26 is not limited to that described above, and may be formed of any material that causes photoelectric conversion.

  It should be noted that the configuration of the photoelectric conversion cell 12 is not limited to the above-described mode and can take various modes. For example, the photoelectric conversion cell 12 may have a configuration in which both an n-type semiconductor and a p-type semiconductor are sandwiched between a first electrode layer and a second electrode layer. In this case, the second electrode layer may not be composed of an n-type semiconductor. In addition, the photoelectric conversion cell 12 is not limited to a pn-coupled structure, but has a pin-coupled structure including an intrinsic semiconductor layer (i-type semiconductor) between an n-type semiconductor and a p-type semiconductor. You may have.

  The first electrode layers 22 of the photoelectric conversion cells 12 adjacent to each other are electrically separated from each other by the division part P1. Similarly, the second electrode layers 24 of the photoelectric conversion cells 12 adjacent to each other are electrically separated from each other by the division part P3. The photoelectric conversion layers 26 of the photoelectric conversion cells 12 adjacent to each other are separated from each other by the division parts P2 and P3.

  The photoelectric conversion module 10 may have an electrical connection 34 between the photoelectric conversion cells 12 adjacent to each other. The electrical connection part 34 electrically connects the photoelectric conversion cells 12 adjacent to each other in series.

  The electrical connection part 34 extends in the thickness direction of the photoelectric conversion module 10 at the second division part P <b> 2, so that the first electrode layer 22 of one photoelectric conversion cell 12 and the second electrode layer 24 of the other photoelectric conversion cell 12. Are electrically connected to each other.

  The photoelectric conversion module 10 includes a plurality of first grid electrodes 31 that are provided side by side in the first direction (Y direction in the drawing) in each photoelectric conversion cell 12. Each first grid electrode 31 extends in a second direction (X direction in the drawing) intersecting the first direction. The first grid electrode 31 may be provided between the photoelectric conversion layer 26 and the second electrode layer 24 of each photoelectric conversion cell 12. The first grid electrode 31 may be made of a material having higher conductivity than the transparent electrode layer constituting the second electrode layer 24. The first grid electrode 31 may be in direct contact with the transparent electrode layer. The width of the first grid electrode 31 in the second direction (the Y direction in the figure) may be, for example, 5 to 100 μm. The thickness of the first grid electrode 31 may be, for example, 0.1 to 20 μm.

  As needed, the 2nd grid electrode 32 extended in a 1st direction (Y direction of a figure) may be provided in the edge part of the 1st grid electrode 31 in a 2nd direction (X direction of a figure). The second grid electrode 32 is connected to the first grid electrode 31 at one end of the first grid electrode 31. The width of the second grid electrode 32 in the first direction (X direction in the figure) may be, for example, 5 to 200 μm. The thickness of the second grid electrode 32 may be, for example, 0.1 to 20 μm.

  The first grid electrode 31 and / or the second grid electrode 32 are provided between the photoelectric conversion layer 26 and the second electrode layer (transparent electrode layer) 24. That is, the first grid electrode 31 and / or the second grid electrode 32 are covered with the transparent electrode layer. Thereby, the connection defect with respect to the transparent electrode of the 1st grid electrode 31 and / or the 2nd grid electrode 32 can be suppressed. Therefore, the fall of the current collection capability of the 1st grid electrode 31 and / or the 2nd grid electrode 32 can be suppressed, As a result, the fall of the conversion efficiency of a photoelectric conversion module can be suppressed.

  Furthermore, as shown in FIG. 3, it is preferable that the 1st grid electrode 31 and / or the 2nd grid electrode 32 are separated from the photoelectric converting layer 26 in the thickness direction. In the embodiment shown in FIG. 3, the first grid electrode 31 and / or the second grid electrode 32 are separated from the photoelectric conversion layer 26 via the transparent electrode layer 25 in the thickness direction. That is, the first grid electrode 31 and / or the second grid electrode 32 are sandwiched between two transparent electrode layers in the thickness direction. Here, the two transparent electrode layers 24 and 25 may be made of the same material, or may be made of different materials. In the present embodiment, since the first grid electrode 31 and / or the second grid electrode 32 are sandwiched between the transparent electrode layers, the connection failure of the first grid electrode 31 and / or the second grid electrode 32 to the transparent electrode is further reduced. Can be suppressed.

  In the present embodiment, the electrical connection portion 34 is formed by a portion continuous from the transparent electrode layer 25. In this case, the electrical connection portion 34 may be made of the same material as the transparent electrode layer 25. Instead, the electrical connection portion 34 may be made of a conductive material different from that of the transparent electrode layer 25. For example, the electrical connection portion 34 may be made of the same material as that of the first grid electrode 31 or the second grid electrode 32.

  The thickness of at least one of the first grid electrode 31 and the second grid electrode 32 (or electrical connection part 34) at the intersection of the first grid electrode 31 and the second grid electrode 32 (or electrical connection part 34), preferably both The thickness of the first grid electrode 31 and the second grid electrode 32 (or the electrical connection portion 34) at a position away from the intersection is preferably thicker. For example, the thickness of the first grid electrode 31 may gradually increase toward the intersection of the first grid electrode 31 and the second grid electrode 32 (or the electrical connection portion 34). Further, the thickness of the second grid electrode 32 (or the electrical connection portion 34) may gradually increase as it goes to the intersection between the first grid electrode 31 and the second grid electrode 32 (or the electrical connection portion 34). .

  When light is applied to the photoelectric conversion layer 26 of each photoelectric conversion cell 12, an electromotive force is generated, and the first electrode layer 22 and the second electrode layer 24 become a positive electrode and a negative electrode, respectively. Accordingly, a part of free electrons generated in a certain photoelectric conversion cell 12 passes from the second electrode layer 24 (and the transparent electrode layer 25) through the electrical connection portion 34, and the first electrode layer 22 of the adjacent photoelectric conversion cell 12. Move to. In addition, another part of the free electrons generated in a certain photoelectric conversion cell 12 is electrically connected to the electrical connection portion 34 from the second electrode layer 24 (and the transparent electrode layer 25) via the first grid electrode 31 and the second grid electrode 32. And move to the first electrode layer 22 of the adjacent photoelectric conversion cell 12. Thus, free electrons generated in the photoelectric conversion cell 12 flow through the plurality of photoelectric conversion cells 12 in the second direction (X direction in the figure).

  The photoelectric conversion module 10 has a wiring 50 for supplying power to the photoelectric conversion module 10 or taking it out from the photoelectric conversion module 10. The wiring 50 may be provided adjacent to the photoelectric conversion cell 12 located at the end of the photoelectric conversion module 10 in the second direction (X direction in the drawing).

  The plurality of first grid electrodes 31 described above include a main grid electrode 31a and a subgrid electrode 31b. The sub grid electrode 31b is provided between the main grid electrodes 31a adjacent to each other in the first direction (Y direction). The subgrid electrode 31b has a length shorter than the length of the main grid electrode 31a along the second direction (X direction). The main grid electrode 31a and the sub grid electrode 31b may be arranged in a predetermined pattern in the first direction (Y direction). Each of the main grid electrode 31a and the sub grid electrode 31b may be arranged at a predetermined pitch in the first direction.

  The number of sub-grid electrodes 31b between main grid electrodes 31a adjacent to each other in the first direction (Y direction) is not particularly limited, and may be, for example, one or more. In this case, the lengths of the sub-grid electrodes 31b adjacent to each other in the first direction (Y direction) along the second direction (X direction) may be the same (for example, refer to FIG. 2) or different from each other. (See, for example, FIG. 6).

  By providing the short sub-grid electrodes 31b between the long main grid electrodes 31a, the area ratio of the first grid electrodes 31 occupying the entire photoelectric conversion module in a top view without reducing the total number of the first grid electrodes 31 ( The area density of the grid electrodes per unit area when the photoelectric conversion module is viewed in plan can be reduced. Thereby, it is possible to balance both the problem of power loss due to the electrical resistance value of the transparent electrode layer and the problem of reduction of short-circuit current due to light shielding by the first grid electrode 31.

  In the present embodiment, the transparent electrode layers 24 and 25 may include a region 2R as shown in FIG. 2 and a region 6R as shown in FIG. In the present embodiment, the region 2R and the region 6R are arranged in different photoelectric conversion cells 12. Instead, the region 2R and the region 6R may be arranged in the same photoelectric conversion cell 12.

  In the region 2R, the number of sub-grid electrodes 31b provided between the main grid electrodes 31a adjacent to each other in the first direction (Y direction) is equal to the number of first grids adjacent to each other in the first direction (Y direction) in the region 6R. The number is smaller than the number of sub-grid electrodes 31b provided between the electrodes 31. Here, the region 2R of the transparent electrode layers 24 and 25 has a sheet resistance smaller than the sheet resistance in the region 6R, a film thickness larger than the film thickness in the region 6R, or a transmittance smaller than the transmittance in the region 6R. For example, when the interval between the main grid electrodes 31a is constant, the smaller the sheet resistance, the smaller the number of sub-grid electrodes 31b arranged between the main grid electrodes 31a, in other words, between the main grid electrodes 31a. The area of the sub-grid electrode 31b (area when the photoelectric conversion module is viewed in plan) may be small.

  Here, the sheet resistance, film thickness, and transmittance of the transparent electrode layers 24, 25 are respectively the sheet resistance, film thickness, and film thickness of the laminate composed of the transparent electrode layer 25 and the transparent electrode layer 25 constituting the second electrode layer 24. It is defined by the transmittance. However, as will be described later, when the transparent electrode layer 25 is not present, the sheet resistance, the film thickness, and the transmittance of the transparent electrode layers 24 and 25 are respectively the transparent electrode layers constituting the second electrode layer 24. It can be read by only the sheet resistance, film thickness and transmittance (the same applies hereinafter).

  As the sheet resistance of the transparent electrode layers 24 and 25 is smaller, the number of sub grid electrodes 31b between the adjacent main grid electrodes 31a is reduced. Accordingly, the area ratio of the first grid electrode 31 occupying the entire photoelectric conversion module in a top view as the region where the sheet resistance of the transparent electrode layers 24 and 25 is smaller (the grid electrode per unit area when the photoelectric conversion module is viewed in plan view) Area density). Therefore, the distribution of the electrical resistance value of both the transparent electrode layer and the first grid electrode 31 approaches uniformly. In this way, by making the overall sheet resistance close to uniform and reducing the density of the first grid electrodes 31 in unnecessary areas (area density of the grid electrodes per unit area when the photoelectric conversion module is viewed in plan) It is possible to balance both the problem of power loss due to the electrical resistance value of the transparent electrode layer and the problem of reduction of short-circuit current due to light shielding by the first grid electrode.

  Instead of the configuration related to the number of subgrid electrodes 31b described above, the number of subgrid electrodes 31b between main grid electrodes 31a adjacent in the first direction may be the same. In this case, the length of the subgrid electrode 31b along the first direction (Y direction) in the region 6R may be longer than the length of the subgrid electrode 31b along the first direction (Y direction) in the region 2R. . Here, as described above, the region 2R preferably has a sheet resistance smaller than the sheet resistance in the region 6R, a film thickness larger than the film thickness in the region 6R, or a transmittance smaller than the transmittance in the region 6R. .

  By reducing the length of the sub-grid electrode 31b in the region where the sheet resistance of the transparent electrode layers 24 and 25 is small, the region where the sheet resistance of the transparent electrode layers 24 and 25 is small is the first to occupy the entire photoelectric conversion module in a top view. The area ratio of one grid electrode 31 (area density of grid electrodes per unit area when the photoelectric conversion module is viewed in plan) can be reduced. Therefore, the distribution of the electrical resistance value of both the transparent electrode layer and the first grid electrode 31 approaches uniformly. In this way, by making the overall sheet resistance close to uniform and reducing the density of the first grid electrodes 31 in unnecessary areas (area density of the grid electrodes per unit area when the photoelectric conversion module is viewed in plan) It is possible to balance both the problem of power loss due to the electrical resistance value of the transparent electrode layer and the problem of reduction of short-circuit current due to light shielding by the first grid electrode.

  In general, the smaller the film thickness of the transparent electrode layer, the higher the sheet resistance of the transparent electrode layer. Furthermore, it is considered that the sheet resistance of the transparent electrode layer increases as the transmittance of the transparent electrode layer increases. This is probably because when the transmittance of the transparent electrode layer is large, the film thickness of the transparent electrode layer is generally small, or the carrier concentration of the transparent electrode layer is low.

  Therefore, as described above, the number of sub-grid electrodes 31b between the main grid electrodes 31a or the length of the sub-grid electrodes 31b along the second direction is changed according to the film thickness or transmittance of the transparent electrode layer. This also makes it possible to make the distribution of the electric resistance value of both the transparent electrode layer and the first grid electrode 31 closer to uniform. Even in this case, the overall sheet resistance is made closer to uniform, and the density of the first grid electrode 31 is reduced in an unnecessary area, thereby causing a problem of power loss due to the electrical resistance value of the transparent electrode layer. And the problem of reducing short-circuit current due to light shielding by the first grid electrode can be balanced.

  Here, the film thickness or transmittance of the transparent electrode layer can be measured more easily than the sheet resistance of the transparent electrode layer in the production line. Therefore, when the number or length of the subgrid electrodes 31b is set according to the film thickness or transmittance of the transparent electrode layer, the merit in manufacturing the photoelectric conversion module 10 is high.

  In the above embodiment, the photoelectric conversion module 10 has a plurality of regions in which the patterns of the main grid electrode 31a and the sub grid electrode 31b are different. Instead, the patterns of the main grid electrode 31a and the sub grid electrode 31b of the photoelectric conversion module 10 may be substantially the same in the entire region. For example, when the sheet resistance of the transparent electrode layer does not substantially vary, it is not necessary to change the patterns of the main grid electrode 31 a and the sub grid electrode 31 b in the same photoelectric conversion module 10.

  FIG. 7 is a schematic cross-sectional view of a photoelectric conversion module according to the second embodiment. Hereinafter, description of the same configuration as that of the first embodiment may be omitted. In the photoelectric conversion module according to the second embodiment, the first grid electrode 31 and the second grid electrode 32 are provided on the second electrode layer 24. That is, the first grid electrode 31 and the second grid electrode 32 are not covered with the second electrode layer 24.

  FIG. 8 is a schematic cross-sectional view of a photoelectric conversion module according to the third embodiment. Hereinafter, description of the same configuration as that of the first embodiment may be omitted. In the photoelectric conversion module according to the third embodiment, the first grid electrode 31 and the second grid electrode 32 are covered with the second electrode layer 24. Furthermore, the first grid electrode 31 and the second grid electrode 32 are separated from the photoelectric conversion layer 26 in the thickness direction. In the present embodiment, the first grid electrode 31 and the second grid electrode 32 are separated from the photoelectric conversion layer 26 via the first buffer layer 27a in the thickness direction.

  The first buffer layer 27a may be a semiconductor material having the same conductivity type as the second electrode layer 24, or may be a semiconductor material having a different conductivity type. The first buffer layer 27 a only needs to be made of a material having a higher electrical resistance than the second electrode layer 24. In an example of a CIS-based photoelectric conversion module, the first buffer layer 27a may be a Zn-based buffer layer, a Cd-based buffer layer, or an In-based buffer layer. The Zn-based buffer layer may be, for example, ZnS, ZnO, Zn (OH), ZnMgO, or a mixed crystal or laminated body thereof. The Cd-based buffer layer may be, for example, CdS, CdO, Cd (OH), a mixed crystal or a laminate thereof. The In-based buffer layer may be, for example, InS, InO, or In (OH), or a mixed crystal or stacked body thereof.

  FIG. 9 is a schematic cross-sectional view of a photoelectric conversion module according to the fourth embodiment. In the photoelectric conversion module according to the fourth embodiment, the first grid electrode 31 and the second grid electrode 32 are covered with the second electrode layer 24. The first grid electrode 31 and the second grid electrode 32 are separated from the photoelectric conversion layer 26 via the first buffer layer 27a in the thickness direction. Further, the photoelectric conversion cell 12 has a second buffer layer 27 b between the second electrode layer 24 and the grid electrodes 31 and 32. That is, the first grid electrode 31 and the second grid electrode 32 may be sandwiched between the first buffer layer 27a and the second buffer layer 27b in the thickness direction.

  The second buffer layer 27b may be a semiconductor material having the same conductivity type as the second electrode layer 24, or may be a semiconductor material having a different conductivity type. In an example of the CIS-based photoelectric conversion module, the second buffer layer 27b may be a Zn-based buffer layer, a Cd-based buffer layer, or an In-based buffer layer as described above. The material constituting the second buffer layer 27b may be the same as or different from the material constituting the first buffer layer 27a.

  FIG. 10 is a schematic top view of a connecting portion between the first grid electrode 31 and the second grid electrode 32 according to the first modification. In the first modification, the width of the first grid electrode 31 in the first direction (Y direction) becomes wider as it approaches the second grid electrode 32. Specifically, the width of the first grid electrode 31 in the first direction (Y direction) gradually increases as it approaches the second grid electrode 32.

  On the contrary, the width of the second grid electrode 32 in the second direction (X direction) may gradually increase as it approaches the first grid electrode 31.

  FIG. 11 is a schematic top view of a connecting portion between the first grid electrode 31 and the second grid electrode 32 according to the second modification. In the second modification, the width of the first grid electrode 31 in the first direction (Y direction) becomes wider as it approaches the second grid electrode 32. Specifically, the width of the first grid electrode 31 in the first direction (Y direction) gradually increases as it approaches the second grid electrode 32.

  On the contrary, the width of the second grid electrode 32 in the second direction (X direction) may be gradually increased as it approaches the first grid electrode 31.

  In the first modification and the second modification, by increasing the area of the connection portion between the first grid electrode 31 and the second grid electrode 32, the electricity in the connection portion between the first grid electrode 31 and the second grid electrode 32 is increased. Connection failure or increase in electrical resistance can be suppressed.

  FIG. 12 is a schematic top view of a connecting portion between the first grid electrode 31 and the second grid electrode 32 according to the third modification. In the third modification, the first grid electrode 31 approaches the second grid electrode 32 and is bent in the first direction (Y direction). Thus, since the connection location of the 1st grid electrode 31 and the 2nd grid electrode 32 is bent, it can reduce that the electric current which flows into the 1st grid electrode 31 reflects in a connection location.

  As another modified example, the first grid electrode 31 may approach the second grid electrode 32 and increase in thickness.

  Next, a method for manufacturing a photoelectric conversion module according to an embodiment will be described with reference to FIGS. 13 to 18 show a method for manufacturing the photoelectric conversion module according to the first embodiment. In each of the following steps, each layer can be appropriately formed by a film forming means such as a sputtering method or a vapor deposition method.

  First, a strip-shaped photoelectric conversion cell 12 including a first electrode layer 22, a transparent electrode layer 25, and a photoelectric conversion layer 26 between the first electrode layer 22 and the transparent electrode layer 25 is formed on the substrate 20. (Cell formation step). Specifically, first, a material constituting the first electrode layer 22 is formed on the substrate 20. The material constituting the first electrode layer 22 is formed in a region extending over the plurality of photoelectric conversion cells 12. The materials of the substrate 20 and the first electrode layer 22 are as described above. Next, a part of the material constituting the first electrode layer 22 is removed in a thin line shape, thereby forming the first divided portion P1 for forming the first electrode layer 22 into a plurality of strips. The removal of a part of the material constituting the first electrode layer 22 can be performed by means such as a laser or a needle.

  Next, a material constituting the photoelectric conversion layer 26 is formed on the first electrode layer 22. The material of the photoelectric conversion layer 26 is as described above. At this time, the material constituting the photoelectric conversion layer 26 may be filled also in the first divided portion P1. Instead, the first divided portion P1 may be filled with another insulating member different from the material constituting the photoelectric conversion layer 26. Next, a part of the material constituting the photoelectric conversion layer 26 is removed in a thin line shape, thereby forming the second divided portion P2 for forming the photoelectric conversion layer 26 into a plurality of strips.

  Next, a material constituting the transparent electrode layer 25 is formed on the photoelectric conversion layer 26. The material of the transparent electrode layer 25 is as described above. The material constituting the transparent electrode layer 25 may also be filled in the second divided portion P2. The transparent electrode layer 25 filled also in the second division part P2 constitutes the electrical connection part 34 described above. Instead, the second divided portion P2 may be filled with another conductive material different from the material constituting the transparent electrode layer 25.

  The method for manufacturing the photoelectric conversion module may include a step of measuring the sheet resistance, film thickness, or transmittance of the transparent electrode layers 24 and 25. The sheet resistance of the transparent electrode layers 24 and 25 can be measured by, for example, a resistance measuring device using a four-terminal method or a resistance measuring device using the Hall effect. The film thickness of the transparent electrode layers 24 and 25 can be measured by, for example, a spectrophotometer, an optical interference film thickness meter, a SEM (scanning electron microscope), a step meter, or a laser microscope. The transmittance of the transparent electrode layer can be measured by, for example, a spectrophotometer.

  Here, the measurement of the sheet resistance, film thickness, or transmittance of the transparent electrode layer may be performed on a photoelectric conversion module used as a finished product, or a dummy photoelectric conversion module that is not used as a finished product, or a dummy It may be performed on the glass substrate. When the photoelectric conversion module 10 is mass-produced, in the same production line (lot), the sheet resistance, film thickness, or transmittance distribution of the transparent electrode layer is almost the same between products. Therefore, a product that is not used as a finished product, for example, a semi-finished product formed up to the photoelectric conversion layer 26 on the substrate 20 or a dummy glass substrate on which a transparent electrode layer is formed is taken out, and the taken-out semi-finished product or dummy You may measure the sheet resistance of a transparent electrode layer, a film thickness, or the transmittance | permeability with respect to this glass substrate. Thereby, the sheet resistance, film thickness, or transmittance of the transparent electrode layer of the photoelectric conversion module 10 used as a product in the same production line (lot) can be estimated.

  In addition, when the transparent electrode layers 24 and 25 are overlapped in the finished product as in this embodiment, the sheet resistance, film thickness, or transmittance of the entire two transparent electrode layers 24 and 25 are measured or It may be estimated. Instead, when the second electrode layer 24 as the transparent electrode layer is only one layer in the finished product, the sheet resistance, film thickness, or transmittance of the single transparent electrode layer 24 may be measured or estimated. .

  The method for manufacturing the photoelectric conversion module may include a grid forming step for forming the grid electrodes 31 and 32 after the cell forming step. The grid formation process may include a first grid formation process and a second grid formation process. The first grid formation step may be performed at any timing before or after the second grid formation step. Moreover, you may implement a grid formation process before the 3rd division part P3 is formed.

  In the first grid formation step, a plurality of first grid electrodes provided in the photoelectric conversion cell 12 in a first direction (Y direction in the figure) and extending in a second direction (X direction in the figure) intersecting the first direction. 31 is formed. In the second grid formation step, the second grid electrode 32 extending in the first direction (Y direction in the figure) as described above is formed.

  The first grid electrode 31 and / or the second grid electrode 32 can be formed by, for example, inkjet printing, screen printing, gravure offset printing, or flexographic printing. Hereinafter, an example in which the first grid electrode 31 and the second grid electrode 32 are formed by application of conductive ink, for example, ink jet printing will be described with reference to FIGS. 14 and 15.

  The conductive ink 102 may be composed of a conductive paste containing conductive particles such as silver and copper, an organic solvent, and a dispersant. Further, the conductive ink 102 may include a binder as necessary. The conductive ink 102 is formed on the transparent electrode layer 25 by being discharged from the nozzle 100. The conductive ink 102 is preferably baked after being applied. By firing the conductive ink 102, the organic solvent and the dispersant are vaporized, and the conductive particles remain in a predetermined coating pattern. Thereby, the first grid electrode 31 and the second grid electrode 32 are formed.

  In the present embodiment, the conductive ink 102 is disposed on the transparent electrode layer 25. Alternatively, the conductive ink 102 may be disposed on the first buffer layer 27a according to the various embodiments described above. Without being limited to these examples, the conductive ink 102 may be disposed above the photoelectric conversion layer 26.

  In one example, the firing temperature of the conductive ink 102 may range from 100 ° C to 200 ° C. In the case of the above-described CIS-based photoelectric conversion module, the firing temperature of the conductive ink 102 is preferably 150 ° C. or lower in order to suppress deterioration and destruction of the photoelectric conversion cell constituting the CIS-based photoelectric conversion module. The firing of the conductive ink 102 is more preferably performed in the air (more preferably dry air) or in a nitrogen atmosphere. The firing time may be in the range of 5 to 60 minutes, for example. The conductive ink may be baked in a heating process for forming the second electrode layer 24. Specifically, when the second electrode layer 24 is formed by a sputtering method, an MOCVD method, or an ion plating method, there is a heating step (a preliminary heating step or a film-forming heating step). Since the heating step when forming the second electrode layer 24 is performed at 100 to 200 ° C., the conductive ink may be baked in this heating step.

  Preferably, in the first grid formation step, the start point S1 at which application of the conductive ink 102 is started in one photoelectric conversion module is located in an ineffective region NER that does not contribute to the electromotive force of the photoelectric conversion module (see FIG. 14). Specifically, as shown in FIG. 14, the nozzle 100 of the inkjet head is scanned in the second direction (X direction) from the start point S1, and the conductive ink 102 is ejected from the nozzle 100, thereby causing the second direction. A conductive ink 102 is formed along the line.

  In the second grid formation step, it is preferable that the start point S2 at which application of the conductive ink 102 is started in one photoelectric conversion module is located in the ineffective region NER that does not contribute to the electromotive force of the photoelectric conversion module. (See FIG. 15). Specifically, as shown in FIG. 15, the nozzle 100 of the inkjet head is scanned in the first direction (Y direction) from the start point S2, and the conductive ink 102 is ejected from the nozzle 100, thereby causing the second direction. A conductive ink 102 is formed along the line.

  Here, the above-described ineffective area NER is defined by an area that does not contribute to photoelectric conversion in the middle of manufacturing or after completion of the product. The non-effective region NER is separated by, for example, excision of the first electrode layer 22, the photoelectric conversion layer 26, and the second electrode layer 24 from the photoelectric conversion cell 12 that contributes to photoelectric conversion, at least the region where the second electrode layer 24 is excised. It may be a region that does not contribute to the photoelectric conversion performed, or a region cut out from the photoelectric conversion module 10 being manufactured.

  Here, when the photoelectric conversion module is mass-produced, there may be a period (lead time) in which the conductive ink 102 is not applied before the ink application is started at the start points S1 and S2. If the conductive ink 102 dries during this period, the conductive ink 102 may not be accurately applied to the start points S1 and S2. In this aspect, since the start points S1 and S2 are located in the ineffective area NER, even if the conductive ink 102 is not accurately applied to the start points S1 and S2, the performance of the photoelectric conversion module is hardly affected.

  After the grid electrode forming step, a material constituting the second electrode layer 24 is formed on the transparent electrode layer 25, the first grid electrode 31, and the second grid electrode 32. The material of the second electrode layer 24 is as described above. Next, the second electrode layer 24, the transparent electrode layer 25, and the photoelectric conversion layer 26 are removed by thinly removing a part of the material constituting the second electrode layer 24, the transparent electrode layer 25, and the photoelectric conversion layer 26. A third divided portion P3 for forming a plurality of strips is formed.

  In a specific example, as shown in FIG. 16, the method for manufacturing the photoelectric conversion module is at least the second electrode layer 24 and the transparent electrode layer 25, preferably the second electrode layer 24, the transparent electrode layer 25, and the photoelectric conversion layer 26. There may be a step of removing a part of. The region where at least the second electrode layer 24 and the transparent electrode layer 25 are removed constitutes an ineffective region NER. The start point S1 at which application of the conductive ink 102 is started may be located in this ineffective area NER.

  In addition, as shown in FIG. 17, the wiring 50 described above may be formed in a region where at least the second electrode layer 24 and the transparent electrode layer 25 are removed. In this case, the region where at least the second electrode layer 24 and the transparent electrode layer 25 are removed may be an end region in the second direction (X direction) of the photoelectric conversion module 10.

  In a specific example, the method for manufacturing a photoelectric conversion module may further include a step of cutting a region including a start point S2 at which application of the conductive ink 102 is started, as illustrated in FIG.

  As described above, the photoelectric conversion module 10 described in the first embodiment is obtained. In FIGS. 16 and 17 of the above embodiment, at least the second electrode layer 24 and the transparent electrode layer 25 in a portion corresponding to the ineffective region NER are removed. The present invention is not limited to this, and the wiring 50 may be formed on the second electrode layer 24 without removing the second electrode layer 24 and the transparent electrode layer 25. In this case, a dividing groove for dividing the ineffective area NER and the effective area ER contributing to photoelectric conversion may be formed between the wiring 50 and the photoelectric conversion cell 12 adjacent to the wiring 50. This dividing groove can be formed, for example, by removing the first electrode layer 22, the photoelectric conversion layer 26, the transparent electrode layer 25, and the second electrode layer 24.

  As described above, the content of the present invention has been disclosed through the embodiments. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  For example, the photoelectric conversion module 10 may be sealed with a transparent sealing material (not shown).

  In the embodiment described above, the second electrode layer 24 is constituted by a transparent electrode layer. Instead, the first electrode layer 22 may be constituted by a transparent electrode layer. In this case, the second electrode layer 24 may be constituted by a transparent electrode layer or an opaque electrode layer. Further, in this case, the first grid electrode 31 and the second grid electrode 32 are preferably provided adjacent to the first electrode layer 22. In this case, the substrate 20 may be configured by a transparent substrate.

  In the present embodiment, the thin film photoelectric conversion module having an integrated structure (having the divided portions P1 to P3) has been described as an example. However, the present invention is not limited to this, and does not have an integrated structure. It is applicable also to the photoelectric conversion module which does not have the parts P1-P3.

  In addition, the terms “first”, “second”, and “third” in this specification are used to distinguish each term in this specification, and “first” in the specification. It should be noted that the terms “second” and “third” do not necessarily coincide with the terms “first”, “second” and “third” in the claims.

DESCRIPTION OF SYMBOLS 10 Photoelectric conversion module 12 Photoelectric conversion cell 20 Board | substrate 22 1st electrode layer 24 2nd electrode layer (n-type semiconductor)
25 Transparent electrode layer 26 Photoelectric conversion layer (p-type semiconductor)
31 First grid electrode 31a Main grid electrode 31b Sub grid electrode 32 Second grid electrode 50 Wiring

Claims (4)

A photoelectric conversion cell including a first electrode layer, a second electrode layer, and a photoelectric conversion layer between the first electrode layer and the second electrode layer;
A grid electrode provided side by side in the first direction in the photoelectric conversion cell and extending in a second direction intersecting the first direction;
The grid electrode includes a plurality of main grid electrodes and a sub-grid electrode provided between the main grid electrodes adjacent to each other,
The photoelectric conversion module, wherein a length of the sub grid electrode along the second direction is shorter than a length of the main grid electrode along the second direction.   The photoelectric conversion module according to claim 1, wherein the main grid electrode and the sub-grid electrode are repeatedly arranged in a predetermined pattern in the first direction. At least one of the first electrode layer and the second electrode layer is a transparent electrode layer;
The transparent electrode layer includes a first region and a second region,
The first region has a sheet resistance smaller than the sheet resistance in the second region, a film thickness larger than the film thickness in the second region, or a transmittance smaller than the transmittance in the second region,
The number of the sub-grid electrodes provided between the main grid electrodes adjacent to each other in the first direction in the first region is equal to the number of the first grid electrodes adjacent to each other in the first direction in the second region. The photoelectric conversion module according to claim 1, wherein the photoelectric conversion module is smaller than the number of the sub-grid electrodes provided between the two. At least one of the first electrode layer and the second electrode layer is a transparent electrode layer;
The transparent electrode layer includes a first region and a second region,
The first region has a sheet resistance smaller than the sheet resistance in the second region, a film thickness larger than the film thickness in the second region, or a transmittance smaller than the transmittance in the second region,
2. The photoelectric device according to claim 1, wherein a length of the subgrid electrode along the first direction in the first region is shorter than a length of the subgrid electrode along the first direction in the second region. Conversion module.

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