Solar cell submodule, and solar cell module

Abstract

To provide a solar cell submodule and a solar cell module, in which the decrease in efficiency due to an assembly error of the solar cell module can be suppressed.SOLUTION: A solar cell submodule 10 includes a base material 11, a plurality of subcells 121 and 122 formed on the base material 11 in a band shape extending in a first direction, disposed side by side in a second direction, and electrically connected to each other in series, and an electrode part 13 formed outside the subcells 121 and 122 electrically connected to each other in series. A width We, in the second direction, of the end part subcell 121 adjacent to the electrode part 13 out of the subcells 121, 122 is larger than a width Ws in the second direction of the standard subcell 122 other than the end part subcell 121 out of the subcells 121, 122.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a solar cell submodule and a solar cell module. [Background technology]

[0002] Solar cell modules in which solar cells (cells or sub-modules) are arranged between a front protective material and a back protective material, and a sealing material is filled in the space around the solar cells, are widely used. In some solar cell modules, a light-shielding part is formed on the front protective material with, for example, black ceramic paint, and the like, to cover and hide wiring and adhesives (for example, see Patent Document 1).

[0003] As a solar cell submodule used in a solar cell module, one formed by electrically connecting multiple solar cell subcells in series on one substrate is known (see, for example, Patent Document 2). By forming a solar cell into a submodule, the effective area decreases because the areas between the subcells become ineffective areas, but the resistance loss in the transparent electrode can be reduced. Therefore, if the solar cell is appropriately formed into a submodule, the effect of improving the photoelectric conversion efficiency by reducing the resistance loss exceeds the reduction in the effective area. For example, in a perovskite solar cell submodule using a material containing a perovskite compound in the photoelectric conversion layer, multiple strip-shaped submodules each having a width of several mm to several cm are often formed in a state of being lined up in the width direction and electrically connected in series. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-188574 A [Patent Document 2] JP 2013-219066 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a solar cell module including a solar cell submodule having many strip-shaped subcells, if a shading portion that covers wiring materials and the like is formed on a surface protective material using black paint or the like, there is a risk that the shading portion will overlap a part of the submodule at the end due to assembly errors and the like. If the width of the subcell is small, the ratio of the area of ​​the subcell where the light incidence is restricted by the shading portion increases, so that the electromotive force of the subcell at the end may be significantly reduced compared to other subcells. A subcell with a small electromotive force becomes electrical resistance to the output current of the other subcells, and may cause large resistance loss and heat generation. Therefore, an object of the present invention is to provide a solar cell submodule and a solar cell module that can suppress a decrease in efficiency due to assembly errors of the solar cell module. [Means for solving the problem]

[0006] A solar cell submodule according to one embodiment of the present invention comprises a substrate, a plurality of subcells formed on the substrate in strips extending in a first direction, arranged side by side in a second direction, and electrically connected in series, and an electrode portion formed outside the plurality of subcells electrically connected in series, wherein a width in the second direction of an end subcell adjacent to the electrode portion among the plurality of subcells is larger than a width in the second direction of a standard subcell among the plurality of subcells other than the end subcell.

[0007] In the solar cell submodule described above, the width of the end subcell in the second direction may be 1.8 times or more and 5.0 times or less the width of the standard subcell in the second direction.

[0008] A solar cell module according to one embodiment of the present invention comprises the above-mentioned solar cell submodule, a surface protective material covering the front side of the solar cell submodule, a back protective material covering the back side of the solar cell submodule, and a sealing material filled between the surface protective material and the back protective material, wherein the surface protective material has a light-shielding portion formed to cover the entire electrode portion and a portion of the end subcell, and the average width in the second direction of the area exposed from the light-shielding portion of the end subcell is greater than the width in the second direction of the standard subcell.

[0009] In the solar cell module described above, an average value of a width in the second direction of a region of the end subcell exposed from the light-shielding portion may be 1.4 to 2.5 times a width in the second direction of the standard subcell. Effect of the Invention

[0010] According to the present invention, it is possible to suppress a decrease in efficiency due to an assembly error of a solar cell module. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic plan view of a solar cell module according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of the solar cell module of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. For convenience, hatching and component symbols may be omitted, and in such cases, other drawings shall be referred to. For convenience, the dimensions of various components in the drawings have been adjusted for easy viewing. Figure 1 is a schematic plan view of a solar cell module 1 according to one embodiment of the present invention. Figure 2 is a cross-sectional view of the solar cell module 1.

[0013] The solar cell module 1 includes a solar cell submodule 10, wiring material 20, a front surface protective material 30, a back surface protective material 40, and a sealing material 50. The solar cell module 1 of this embodiment is a double-sided power generation type solar cell module in which the outer surface of the front surface protective material 30 is mainly the light receiving surface, but light incident from the back surface protective material 40 can also be photoelectrically converted.

[0014] The solar cell submodule 10 is itself an embodiment of the solar cell submodule according to the present invention. The solar cell submodule 10 includes a base material 11, a plurality of subcells 121, 122 formed on the base material 11 in strip shapes extending in a first direction, arranged in a line in a second direction, and electrically connected in series, and an electrode portion 13 formed on the outside of the plurality of subcells 121, 122 connected in series. The solar cell submodule 10 may include a plurality of series-connected bodies of the subcells 121, 122. In this case, a pair of electrode portions 13 may be provided on the outside of the series-connected bodies of the subcells 121, 122 in the second direction, or the electrode portion 13 and the series-connected bodies of the subcells 121, 122 may be provided alternately in the second direction. In the illustrated example, a series-connected body of two subcells 121, 122 having opposite connection directions (polarities) is provided, and a single electrode portion 13 serving as a common electrode is provided between the series-connected bodies of the two subcells 121, 122.

[0015] The substrate 11 is a structure that supports the subcells 121, 122 and the electrode portion 13. When light is incident on the solar cell submodule 10 from the substrate 11 side, the substrate 11 is made of a transparent material. Specifically, the substrate 11 is made of, for example, a glass plate, a resin sheet, or the like.

[0016] The subcells 121, 122 each independently convert the incident light into electricity and output it. The subcells 121, 122 include an end subcell 121 adjacent to the electrode portion 13 and a standard subcell 122 that is not adjacent to the electrode portion 13 other than the end subcell 121. The width We in the second direction of the end subcell 121 is larger than the width Ws in the second direction of the standard subcell 122. This prevents the effective area of ​​the end subcell 121 (area of ​​the region into which light is not blocked and enters) from becoming smaller than the effective area of ​​the standard subcell 122 when the light incident on the end portion of the solar cell submodule 10 in the second direction is blocked by the structure of the solar cell submodule 10 such as the surface protection material 30 described later. When the effective area of ​​the end subcell 121 becomes smaller than the effective area of ​​the standard subcell 122, the electromotive force of the end subcell 121 becomes smaller than the electromotive force of the multiple standard subcells 122, so that the end subcell 121 becomes an electrical resistance, causing loss and heat generation. Therefore, by preventing the effective area of ​​the end subcells 121 from becoming smaller than the effective area of ​​the standard subcells 122, it is possible to prevent a decrease in the photoelectric conversion efficiency of the entire solar cell module 1, as well as a further decrease in efficiency due to heat and deterioration of the solar cell submodule 10. Note that even if the effective area of ​​the end subcells 121 is larger than the effective area of ​​the standard subcells 122, the standard subcells 122 do not generate a large amount of heat because there are a sufficiently large number of standard subcells 122.

[0017] The lower limit of the width We of the end subcell 121 is preferably 1.8 times, more preferably 2.0 times, the width Ws of the standard subcell 122. On the other hand, the upper limit of the width We of the end subcell 121 is preferably 5.0 times, more preferably 4.0 times, the width Ws of the standard subcell 122. By setting the width We of the end subcell 121 to the lower limit or more, it is possible to more reliably prevent the effective area of ​​the end subcell 121 from being smaller than the effective area of ​​the standard subcell 122 even when the width of the light-shielded region of the end subcell 121 becomes larger than the design value. Furthermore, by setting the width We of the end subcell 121 to the upper limit or less, it is possible to suppress an increase in the electrical resistance of the end subcell 121 in the second direction and prevent a decrease in the output of the solar cell submodule 10. Furthermore, by reducing the width We of the end subcell 121, it is possible to increase the width Ws of the standard subcell 122 in the solar cell submodule 10, and therefore the output of the solar cell submodule 10 can be increased.

[0018] The subcells 121, 122 may have a configuration including, in order from the substrate 11 side, a first electrode layer 14, a photoelectric conversion layer 15, and a second electrode layer 16. The subcells 121, 122 may be formed by repeating a process of forming each layer integrally and then forming separation grooves 17, 18, 19 that separate the subcells 121, 122. At this time, the first electrode layer 14 of each subcell 121, 122 can be connected to the second electrode layer 16 of the subcell 121, 122 adjacent to one side by slightly shifting the position of the separation grooves 17, 18, 19 of each layer. Note that in FIG. 2, the widths of the separation grooves 17, 18, 19 of each layer and the intervals in the second direction are illustrated large for ease of understanding, but in reality, the widths of the separation grooves 17, 18, 19 are very small compared to the widths We and Ws of the subcells 121, 122.

[0019] The first electrode layer 14 and the second electrode layer 16 may be formed of a transparent conductive oxide (TCO) having electrical conductivity and light transmission, a semiconductor thin layer, or the like. As the transparent conductive oxide forming the first electrode layer 14, for example, indium oxide, tin oxide, zinc oxide, titanium oxide, and composite oxides thereof, or the like can be used. Among these, indium-based composite oxides mainly composed of indium oxide are preferred. From the viewpoint of high electrical conductivity and transparency, indium oxide is particularly preferred. Furthermore, in order to ensure reliability or higher electrical conductivity, it is preferred to add a dopant to indium oxide. Examples of dopants include Sn, W, Zn, Ti, Ce, Zr, Mo, Al, Ga, Ge, As, Si, and S. For example, ITO (Indium Tin Oxide), in which tin is added to indium oxide, is widely known.

[0020] The photoelectric conversion layer 15 may be formed from a material containing a perovskite compound. As the perovskite compound, a compound containing an organic atom A containing at least one of a monovalent organic ammonium ion and an amidinium ion, a metal atom B generating a divalent metal ion, and a halogen atom X containing at least one of an iodide ion I, a bromide ion Br, a chloride ion Cl, and a fluoride ion F, and expressed as ABX3, may be used. Among them, when the photoelectric conversion layer 15 is formed by a vapor deposition method (dry process), the organic atom A is preferably methylammonium MA (CH3NH3), the metal atom B is preferably lead Pb, and the halogen atom X is preferably at least one of an iodide I, a bromide ion Br, and a chloride ion Cl.

[0021] Specifically, preferred perovskite compounds include methylammonium lead halide MAPbX3 (CH3NH3PbX3), MAPbI3, MAPbBr3, MAPbCl3, etc. Note that the halogen atom X may contain multiple types. Examples of perovskite compounds containing iodide I and other halogen atoms X include methylammonium lead iodide MAPbIy X (3-y) (CH3NH3PbI y X (3-y) ), MAPbI y Br (3-y) , MAPbI y Cl (3-y) etc. (y is any positive integer).

[0022] When the perovskite compound is methylammonium lead halide (MAPbX3(CH3NH3PbX3)), the photoelectric conversion layer 15 can be formed by sequentially depositing a lead halide (PbX2) material and a methylammonium halide (MAX) material, and reacting the thin films of these materials at a reaction temperature. For example, when the perovskite compound is methylammonium lead iodide (MAPbI y X (3-y) (CH3NH3PbI y X (3-y) In the case of the above, the photoelectric conversion layer 15 is formed by sequentially depositing a lead halide (PbX2) material and a methylammonium iodide (MAI) material, and reacting the thin films of these materials at a reaction temperature. The photoelectric conversion layer 15 can also be formed by a method such as a sol-gel method in which a perovskite compound is synthesized in a liquid-phase coating, or a coating method in which a solution containing a pre-synthesized perovskite compound is applied.

[0023] The electrode unit 13 is connected to the first electrode layer 14 or the second electrode layer 16 of the adjacent subcells 121, 122, and is used as a connection terminal for connecting the series-connected subcells 121, 122 to another series-connected subcell 121, 122 or to the outside of the solar cell module 1 by the wiring material 20. The electrode unit 13 may have a first electrode layer 14, a photoelectric conversion layer 15, and a second electrode layer 16 formed integrally with the subcells 121, 122, or may have only the first electrode layer 14 with the photoelectric conversion layer 15 and the second electrode layer 16 removed. The electrode unit 13 may also have an external electrode 131 laminated on the first electrode layer 14 or the second electrode layer 16 to facilitate connection of the wiring material 20. The external electrode 131 may be formed of a sintered body of a conductive paste such as a silver paste. When the electrode unit 13 has a first electrode layer 14, a photoelectric conversion layer 15, and a second electrode layer 16, and a wiring material 20 is connected to the second electrode layer 16, the electrode unit 13 may be capable of photoelectric conversion integrally with the adjacent end subcells 121 without forming separation grooves 17, 18, 19 between the electrode unit 13 and the adjacent end subcells 121. In this case, the electrode unit 13 is understood to be a region in which an external electrode 131 is formed and its outer region in the second direction.

[0024] The wiring material 20 is connected to the external electrode 131, and electrically connects between the series-connected subcells 121, 122 or between the series-connected subcells 121, 122 and the outside. As the wiring material 20, for example, a metal foil, a metal wire, a twisted metal wire, a braided metal wire, or the like is suitably used.

[0025] The surface protective material 30 protects the solar cell submodule 10 by covering the front side of the solar cell submodule 10 via the sealing material 50. The surface protective material 30 can be formed from a plate-shaped or sheet-shaped material, and is preferably excellent in light transmission, water blocking, scratch resistance, and weather resistance. Specifically, examples of the material for the surface protective material 30 include transparent resins such as acrylic resins and polycarbonate resins, and glass. In addition, the surface of the surface protective material 30 may be processed into an uneven shape or coated with an anti-reflective coating layer in order to suppress light reflection.

[0026] The surface protective material 30 has a surface shading portion 31 (shown hatched in FIG. 1) formed so as to cover the entire electrode portion 13 and a portion of the end subcell 121. The surface shading portion 31 improves the aesthetic appearance by concealing the external electrode 131 and the wiring material connected to the external electrode 131. The surface shading portion 31 can be formed, for example, by applying a black paint. Ceramic paint is generally used as the black paint. Since the surface shading portion 31 covers a portion of the end subcell 121, the electrode portion 13 is not exposed from the surface shading portion 31 even if there is an assembly error of the solar cell module 1 (misalignment of the relative positions of the surface protective material 30 and the solar cell submodule 10), so that the aesthetic appearance of the solar cell module 1 can be prevented from being impaired.

[0027] Furthermore, the average value of the width Wa in the second direction of the region of the end subcells 121 exposed from the front surface light-shielding portion 31 is larger than the width Ws in the second direction of the standard subcell 122. This makes it possible to prevent the effective area of ​​the end subcells 121 (the area of ​​the region exposed from the front surface light-shielding portion 31) from becoming smaller than the effective area of ​​the standard subcell 122 even if the light-shielding width of the end subcells 121 by the front surface light-shielding portion 31 becomes larger than the design value due to an assembly error of the solar cell module 1. This makes it possible to prevent a decrease in the photoelectric conversion efficiency of the entire solar cell module 1, as well as a further decrease in efficiency due to heat generation and deterioration of the solar cell submodule 10.

[0028] The lower limit of the average value of the width Wa of the region of the end subcell 121 exposed from the surface light-shielding portion 31 is preferably 1.4 times, more preferably 1.7 times, the width Ws of the standard subcell 122. On the other hand, the upper limit of the average value of the width Wa of the region of the end subcell 121 exposed from the surface light-shielding portion 31 is preferably 2.5 times, more preferably 2.0 times, the width Ws of the standard subcell 122. By setting the width Wa of the region of the end subcell 121 exposed from the surface light-shielding portion 31 to be equal to or greater than the lower limit, it is possible to more reliably prevent the effective area of ​​the end subcell 121 from being smaller than the effective area of ​​the standard subcell 122 even when the light-shielding width of the end subcell 121 by the surface light-shielding portion 31 becomes larger than the design value due to an assembly error of the solar cell module 1. In addition, by setting the width Wa of the region of the end subcell 121 exposed from the surface light-shielding portion 31 to be equal to or less than the upper limit, it is possible to suppress an increase in the electrical resistance of the end subcell 121 in the second direction and prevent a decrease in the output of the solar cell submodule 10. Furthermore, by reducing the width Wa of the region of the end subcell 121 exposed from the front surface light-shielding portion 31, the width Ws of the standard subcell 122 can be increased, thereby increasing the output of the solar cell submodule 10.

[0029] The back surface protective material 40 protects the solar cell submodule 10 by covering the back side of the solar cell submodule 10 via the sealing material 50. The back surface protective material 40 can be formed from a plate-shaped or sheet-shaped material. When the solar cell submodule 10 converts light incident from the back surface side into electric power, the back surface protective material 40 can be formed from a material similar to that of the front surface protective material 30 and can be configured to have a back surface shading portion 41 formed so as to cover the entire electrode portion 13 and a part of the end subcell 121 in the same manner as the front surface shading portion 31. The width Wa of the region of the end subcell 121 exposed from the back surface shading portion 41 of the back surface protective material 40 is also set to be the same as the width Wa of the region exposed from the front surface shading portion 31 of the front surface protective material 30. When the solar cell submodule 10 converts only light incident from the front surface side into electric power, the back surface protective material 40 may be formed from a light-reflecting material so as to reflect light transmitted through the solar cell submodule 10 and re-enter the solar cell submodule 10.

[0030] The sealing material 50 is filled between the light-receiving surface of the solar cell submodule 10 and the front protective material 30, between the rear surface of the solar cell submodule 10 and the back protective material 40, and around the solar cell submodule 10. The sealing material 50 bonds the solar cell submodule 10 to the front protective material 30 and the back protective material 40, and prevents moisture and the like from coming into contact with the solar cell submodule 10 by eliminating gaps around the solar cell submodule 10.

[0031] As the sealing material 50, for example, a resin having translucency, such as ethylene / vinyl acetate copolymer (EVA), ethylene / α-olefin copolymer, ethylene / vinyl acetate / triallyl isocyanurate (EVAT), polyvinyl butyrate (PVB), acrylic resin, urethane resin, or silicone resin, is preferably used. The sealing material 50 is preferably formed from a material that has thermoplasticity that penetrates into the gaps of the solar cell submodule 10 during the manufacturing stage, and that can retain its shape even when the temperature of the solar cell module 1 increases due to loss of thermoplasticity in the final product. In other words, the sealing material 50 is preferably formed from a resin composition that is mainly made of a thermoplastic resin and contains a crosslinking agent that is activated at a temperature higher than the softening point of the thermoplastic resin and crosslinks and hardens the thermoplastic resin.

[0032] In the solar cell module 1 having the above-mentioned configuration, the width We of the end subcell 121 adjacent to the electrode portion 13 among the multiple subcells 121, 122 of the solar cell submodule 10, and its exposed width Wa from the shading portions 31, 41 are made larger than the width Ws of the standard subcells 122 other than the end subcell 121.This makes it possible to prevent the effective area of ​​the end subcell 121 from becoming smaller than that of the standard subcell 122, which would result in increased internal loss or the occurrence of hot spots, even if the relative position of the solar cell submodule 10 and the front surface shading portion 31 or the back surface shading portion 41 is misaligned.

[0033] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and various modifications and variations are possible. For example, the number of subcell connections in a solar cell submodule and the number of solar cell submodules in a solar cell module can be appropriately changed. In addition, the solar cell submodule according to the present invention may be a so-called see-through type submodule in which the first electrode layer 14, the photoelectric conversion layer 15, and the second electrode layer 16 are removed in a slit shape extending in the second direction, and configured to transmit light. Since solar cell modules using see-through type solar cell submodules are expected to be used in places where design is important, such as windows of buildings, they are often provided with light-shielding parts on the front surface protective material and the back surface protective material, and there is a great demand for the efficiency reduction according to the present invention. [Explanation of symbols]

[0034] 1. Solar cell module 10 Solar cell submodule 11 Base material 121 End Subcell 122 Standard Subcell 13 Electrode part 131 External electrode 14 1st electrode layer 15 Photoelectric conversion layer 16 Second electrode layer 20 Wiring material 30 Surface protection material 31 Surface shading part 40 Back protection material 41 Back light shielding part 50 Encapsulating material

Claims

1. A substrate; a plurality of subcells formed on the base material in a strip shape extending in a first direction and arranged in a second direction and electrically connected in series; and an electrode portion formed outside the plurality of subcells electrically connected in series; a width in the second direction of an end subcell adjacent to the electrode portion among the plurality of subcells is larger than a width in the second direction of a standard subcell other than the end subcell among the plurality of subcells.

2. The solar cell submodule according to claim 1 , wherein the width in the second direction of the end subcell is 1.8 times or more and 5.0 times or less the width in the second direction of the standard subcell.

3. The solar cell submodule according to claim 1 ; a surface protective material for covering a front side of the solar cell submodule; A back surface protection material that covers the back surface of the solar cell submodule; A sealant filled between the front surface protective material and the back surface protective material; Equipped with the surface protection material has a light-shielding portion formed to cover the entire electrode portion and a part of the end subcell, a solar cell module, wherein an average value of a width in the second direction of a region of the end subcell that is exposed from the light-shielding portion is greater than a width in the second direction of the standard subcell.

4. 4. The solar cell module according to claim 3, wherein an average width in the second direction of a region of the end subcell exposed from the light-shielding portion is 1.4 to 2.5 times the width in the second direction of the standard subcell.

Images