Solar cell module

Abstract

Provided is a solar cell module capable of highly suppressing deterioration of a solar cell due to moisture. This solar cell module 1 comprises: a surface protective material 11; an intermediate protective material 12 disposed on the rear side of the surface protective material 11 and having an intermediate through-hole 121; a rear surface protective material 13 disposed on the rear side of the intermediate protective material 12; a thin-film solar cell 14 disposed between the surface protective material 11 and the intermediate protective material 12; a surrounding moisture-proof material 17 disposed in an annular shape surrounding the intermediate through-hole 121 and sandwiched between the intermediate protective material 12 and the rear surface protective material 13; a lead wire 18 extending from the thin-film solar cell 14, passing through the intermediate through-hole 121, and penetrating the surrounding moisture-proof material 17 from the inside to the outside; and a sealing material 20 filled between the surface protective material 11 and the intermediate protective material 12 and between the intermediate protective material 12 and the rear surface protective material 13.

Description

solar cell module

[0001] The present invention relates to a solar cell module.

[0002] Solar cell modules are used in which solar cells are sealed between plate-shaped protective materials. The solar cell module may be configured such that lead wires for outputting power from the solar cells extend to the outside through through-holes formed in the protective material on the back side. In order to prevent moisture from entering the interior of the solar cell module, it has been proposed to fill the through-holes through which the lead wires pass with a filler material (see, for example, Patent Document 1).

[0003] JP 2011-124435 A

[0004] Even if the through holes in the protective material are filled with a filler, the area of ​​the inner circumferential surface of the through holes is small, and sufficient moisture-proofing effect cannot be achieved. Furthermore, external force may act on the lead wires, causing stress on the filler, which may cause it to peel off from the protective material, further reducing moisture-proofing. Thin-film solar cells, such as perovskite solar cells, are particularly susceptible to moisture degradation. Therefore, an object of the present invention is to provide a solar cell module that can effectively suppress moisture-induced degradation of solar cells.

[0005] A solar cell module according to one embodiment of the present invention comprises a surface protective material, an intermediate protective material arranged on the back side of the surface protective material and having an intermediate through hole, a back protective material arranged on the back side of the intermediate protective material, a thin-film solar cell arranged between the surface protective material and the intermediate protective material, an enclosed moisture-proof material arranged in a ring shape surrounding the intermediate through hole and sandwiched between the intermediate protective material and the back protective material, a lead wire extending from the thin-film solar cell, passing through the intermediate through hole, and penetrating the enclosed moisture-proof material from the inside to the outside, and a sealing material filled between the surface protective material and the intermediate protective material and between the intermediate protective material and the back protective material.

[0006] According to the present invention, it is possible to provide a solar cell module that can highly suppress deterioration of solar cells due to moisture.

[0007] 1 is a schematic plan view of a solar cell module according to a first embodiment of the present invention; FIG. 2 is a schematic cross-sectional view of the solar cell module taken along line XX of FIG.

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. For convenience, hatching and component reference numerals may be omitted. In such cases, other drawings should be referenced. Furthermore, the dimensions of various components in the drawings have been adjusted for clarity.

[0009] Fig. 1 is a schematic plan view of a solar cell module 1 according to a first embodiment of the present invention. Fig. 2 is a schematic cross-sectional view of the solar cell module 1 taken along line X-X in Fig. 1. The solar cell module 1 includes a surface protective material 11, an intermediate protective material 12, a rear surface protective material 13, a thin-film solar cell 14, a plurality of rear surface solar cells 15, a peripheral moisture-proof material 16, a surrounding moisture-proof material 17, a pair of first lead wires 18, a pair of second lead wires 19, and a sealing material 20.

[0010] The surface protective material 11 protects the thin-film solar cells 14 by covering the front side of the thin-film solar cells 14 via the encapsulant 20. The surface protective material 11 can be formed from a plate-like or sheet-like material, and preferably has excellent light transmission, water blocking, scratch resistance, and weather resistance. Specific examples of the material for the surface protective material 11 include transparent resins such as acrylic resins or polycarbonate resins, and glass, with glass being particularly preferred. Furthermore, the surface of the surface protective material 11 may be textured or coated with an anti-reflective coating layer to suppress light reflection.

[0011] The surface protection material 11 may have a light-shielding layer 111 having light-shielding properties on its outer periphery. The light-shielding layer 111 may be formed of, for example, black ceramic paint. In order to improve the design of the solar cell module 1, the light-shielding layer 111 is preferably formed to cover the surrounding moisture-proof material 17 and the first lead wire 18 so that they are not visible from the front side of the solar cell module 1. Furthermore, the light-shielding layer 111 can prevent deterioration of the adhesive caused by light entering the adhesive when the solar cell module 1 is fixed to a structure such as a building or a vehicle using an adhesive applied to the back surface of the outer periphery of the solar cell module 1.

[0012] The intermediate protective material 12 is disposed on the back side of the surface protective material 11 and the thin-film solar cells 14 and covers the back side of the thin-film solar cells 14 via the encapsulant 20, thereby protecting the thin-film solar cells 14, particularly from moisture. The intermediate protective material 12 can be formed from the same plate- or sheet-shaped material as the surface protective material 11. The intermediate protective material 12 also has an intermediate through hole 121 through which the first lead wires 18 pass. The intermediate protective material 12 may be formed with a single intermediate through hole 121 through which a pair of first lead wires 18 pass together, or with multiple intermediate through holes 121 through which each individual first lead wire 18 passes. The intermediate through hole 121 is preferably formed so as to be encompassed (entirely covered) by the light-shielding layer 111 in plan view. The diameter of the intermediate through hole 121 is preferably the minimum size necessary to insert the first lead wire 18, and specifically may be 5 mm or more and 15 mm or less.

[0013] The back surface protective material 13 is disposed on the back side of the intermediate protective material 12 and the back-side solar cells 15. It protects the back-side solar cells 15 and prevents moisture from penetrating through the intermediate through-holes 121 to the thin-film solar cells 14 by covering the back side of the intermediate through-holes 121. The back surface protective material 13 preferably has excellent water-blocking, scratch-resistance, and weather resistance, but does not require the same translucency as the surface protective material 11 and the intermediate protective material 12. It may also be colored to make the gaps between the multiple back-side solar cells 15 less noticeable. For this reason, the back surface protective material 13 may be formed from the same plate- or sheet-like material as the surface protective material 11 and the intermediate protective material 12, or may be formed from a metal plate, a composite sheet of metal and resin, or the like. The back surface protective material 13 also has a back-side through-hole 131 through which the first lead wire 18 and the second lead wire 19 pass. The back-side through-hole 131 is spaced from the intermediate through-hole 121 in a plan view and is formed outside the enclosed moisture-proof material 17. Similar to the intermediate through-hole 121, the rear through-hole 131 is preferably formed so as to be encompassed by the light-shielding layer 111 in plan view.

[0014] The surface protective material 11, intermediate protective material 12, and back surface protective material 13 together ensure the structural strength of the solar cell module 1. For this reason, any one of the surface protective material 11, intermediate protective material 12, and back surface protective material 13 is preferably formed from a material with particularly excellent strength, such as tempered glass. Furthermore, the surface protective material 11 or the intermediate protective material 12 may also serve as a support for the thin-film solar cells 14. In this case, the one of the surface protective material 11 and the intermediate protective material 12 that supports the thin-film solar cells 14 is preferably formed from a material that is easy to process, such as non-tempered glass.

[0015] The thin-film solar cells 14 are disposed between the surface protective material 11 and the intermediate protective material 12. The thin-film solar cells 14 may be formed on the surface of an independent support material such as a resin film, but may also be formed on the back surface of the surface protective material 11 or the surface of the intermediate protective material 12. Using the surface protective material 11 or the intermediate protective material 12 as a support for the thin-film solar cells 14 simplifies the structure of the solar cell module 1 and improves the positioning accuracy of the thin-film solar cells 14 relative to the other components.

[0016] For example, the thin-film solar cell 14 may be configured by stacking a first transparent electrode layer, a first charge transport layer, a photoelectric conversion layer, a second charge transport layer, and a second transparent electrode layer in this order. The thin-film solar cell 14 may be divided into a plurality of subcells that independently perform photoelectric conversion and are electrically connected in series, each of which has a first separation groove that separates the first transparent electrode layer, a second separation groove that separates the first charge transport layer, the photoelectric conversion layer, and the second charge transport layer, and a third separation groove that separates the second electrode layer. The thin-film solar cell 14 may also be configured to have ineffective regions on both sides of the active regions (a plurality of subcells) that contribute to photoelectric conversion, where external electrodes to which the first lead wires 18 are connected are provided.

[0017] The first and second transparent electrode layers may be formed of a transparent conductive oxide (TCO) having electrical conductivity and optical transparency, a thin semiconductor layer, or the like. Examples of transparent conductive oxides that can be used to form the first and second transparent electrode layers include indium oxide, tin oxide, zinc oxide, titanium oxide, and composite oxides thereof. Among these, indium-based composite oxides containing indium oxide as a main component are preferred. Indium oxide is particularly preferred from the viewpoints of high electrical conductivity and transparency. Furthermore, it is preferable to add a dopant to indium oxide to ensure reliability or higher electrical conductivity. 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.

[0018] The first charge transport layer and the second charge transport layer selectively pass charges of opposite polarities. That is, one of the first charge transport layer and the second charge transport layer is an electron transport layer that passes electrons, and the other of the first charge transport layer and the second charge transport layer is a hole transport layer that passes holes. Examples of the main material of the electron transport layer include fullerene and PCBM. Examples of fullerenes include C60, C70, and their hydrides, oxides, metal complexes, and derivatives with alkyl groups added thereto, such as PCBM ([6,6]-Phenyl-C61-Butyric Acid Methyl Ester). In particular, forming the electron transport layer from a material containing fullerene encapsulating lithium (Li) can improve electron transport efficiency. The hole transport layer may also have a multilayer structure. The thickness of the hole transport layer can vary greatly depending on the material, the configuration of adjacent layers, and the like, but can be, for example, 3 nm to 50 nm.

[0019] The hole transport layer can be formed from a film of a hole transport layer-forming compound that forms a hole-permeable self-assembled monolayer (SAM). The hole transport layer-forming compound that forms the self-assembled monolayer that becomes the hole transport layer can be a compound having a functional group capable of transporting holes, such as a carbazole-based, phenothiazine-based, or dimethylacridine-based group, and a self-assembled terminal group such as phosphoric acid or carboxylic acid. The hole transport layer-forming compound preferably has a linear structure, such as an alkyl chain, between the functional group and the self-assembled terminal group to impart passivation properties to the hole transport layer. The alkyl chain preferably has four or more carbon atoms. Specific examples of the hole transport layer-forming compound include Me-4PACz ([4-(3,6-Dimethyl-9H-carbazol-9-yl)butyl]phosphonic Acid) and Me-6PACz ([6-(3,6-Dimethyl-9H-carbazol-9-yl)butyl]phosphonic Acid)).

[0020] The photoelectric conversion layer absorbs incident light to generate photocarriers (electrons and holes). The photoelectric conversion layer can be formed from a material containing a perovskite compound. The perovskite compound includes an organic atomic group A including at least one of a monovalent organic ammonium ion and an amidinium ion, a metal atom B that generates a divalent metal ion, and a halogen atom X including at least one of an iodide ion I, a bromide ion Br, a chloride ion Cl, and a fluoride ion F, and the organic atomic group A is represented by the formula ABX. ３ In addition, perovskite compounds in which part or all of the organic atomic group A is substituted with an alkali metal Am are not excluded from the present invention.

[0021] The organic atomic group A is methylammonium MA (CH ３ NH ３ ), Formamidinium FA (CH ３ N ２) and the like. Examples of the alkali metal Am include potassium K, cesium Cs, rubidium Rb, and the like. Among these, when the power generation efficiency of the thin-film solar cell 14 is important, cesium Cs and rubidium Rb are preferred as the alkali metal Am, and cesium Cs is particularly preferred from the standpoints of cost and availability. Examples of the metal atom B include lead Pb and tin Sn. The amounts of lead and tin are adjusted depending on the required band gap. The halogen atom X is preferably at least one of iodide I, bromide Br, and chloride Cl.

[0022] Specifically, preferred perovskite compounds include, for example, MAPbI ３ , MAPbBr ３ , MAPbCl ３ Methylammonium lead halides (MAPbX) such as ３ ), and FAPbI ３ , FAPbBr ３ , FAPbCl ３ Formamidinium lead halide (FAPbX) ３ The halogen atom X may contain multiple types, and the organic atomic group A may be FA containing both methylammonium and formamidinium. ｙ MA 1-ｙ PbX ３ In addition, when the alkali metal Am is contained, Am ｙ FA ｚ MA １－ｙ－ｚ PbIX, Am ｙ FA １－ｙ Am may be a single type of Cs, Rb, or K, or may contain a plurality of types of Am (where y and z are any positive integers).

[0023] The back-side solar cells 15 absorb light of wavelengths that pass through the thin-film solar cells 14, convert it into electricity, and output power. Crystalline silicon solar cells can be used as the back-side solar cells 15. The multiple back-side solar cells 15 are electrically connected to each other and output power from a pair of second lead wires 19. The crystalline silicon solar cell can be configured, for example, by stacking a first semiconductor layer and a second semiconductor layer of opposite polarities on a crystalline silicon substrate, with electrodes for collecting power disposed on the semiconductor layers. The crystalline silicon solar cell may be a double-sided electrode solar cell in which electrodes are disposed on both sides, but is preferably a back-side electrode solar cell in which electrodes are disposed only on the back side.

[0024] The peripheral moisture-proofing material 16 is disposed on the outer periphery of the surface protective material 11 and the intermediate protective material 12 in a plan view and seals the gap between the surface protective material 11 and the intermediate protective material 12. The peripheral moisture-proofing material 16 prevents moisture from entering between the surface protective material 11 and the intermediate protective material 12 from the edge. A thermoplastic adhesive that can be easily adhered to the surface protective material 11 and the intermediate protective material 12 by heat pressing is preferably used as the peripheral moisture-proofing material 16. Among these, a butyl rubber-based thermoplastic adhesive that has excellent moisture-proofing properties and a relatively high melt flow rate is particularly preferred. The peripheral moisture-proofing material 16 may be formed by arranging a strip of material along the outer edges of the surface protective material 11 and the intermediate protective material 12 and then heat pressing, or by applying a molten material to at least one of the surface protective material 11 and the intermediate protective material 12 and then heat pressing. The peripheral moisture-proofing material 16 may also contain hygroscopic particles. As the moisture-absorbing particles contained in the peripheral moisture-proof material 16, for example, silica gel, alumina, zeolite, and talc are preferably used.

[0025] The surrounding moisture-proof material 17 is arranged in the form of a closed ring surrounding the intermediate through-hole 121, i.e., an endlessly extending band, and is sandwiched between the intermediate protective material 12 and the back surface protective material 13. The surrounding moisture-proof material 17 prevents moisture from entering the periphery of the thin-film solar cells 14 through the gap between the intermediate protective material 12 and the back surface protective material 13 and the intermediate through-hole 121. For this reason, the surrounding moisture-proof material 17 may overlap the thin-film solar cells 14 in a plan view, but is arranged so as not to overlap the back-side solar cells 15. The surrounding moisture-proof material 17 may be formed from the same material as the peripheral moisture-proof material 16 so that it can be closely attached to the intermediate protective material 12 and the back surface protective material 13 by heat pressing. Furthermore, the surrounding moisture-proof material 17 is preferably formed by integrating two layers of material that at least partially sandwich the first lead wire 18 by heat pressing to prevent a gap from forming between the first lead wire 18 and the surrounding moisture-proof material 17. The external shape of the enclosed moisture-proof material 17 is not particularly limited, but is preferably a relatively simple rectangular or circular shape. The internal dimensions of the enclosed moisture-proof material 17 need only be equal to or greater than the diameter of the intermediate through-hole 121. The width of the band of the enclosed moisture-proof material 17 depends on the material, etc., but is preferably 8 mm to 20 mm, more preferably 10 mm to 15 mm, so as to block moisture without occupying a large space. The enclosed moisture-proof material 17 is preferably encompassed by the shading layer 111 in plan view so as not to impair the design of the solar cell module 1.

[0026] The first lead wire 18 is a wiring material for outputting power from the thin-film solar cell 14. The first lead wire 18 extends from the thin-film solar cell 14, passes through the intermediate through-hole 121, passes through the surrounding moisture-proof material 17 from the inside to the outside, and further extends to the outside through the back-side through-hole 131. For example, a metal foil, a metal wire, a metal twisted wire, a metal braided wire, or the like is suitably used as the first lead wire 18. The first lead wire 18 may have an insulating coating.

[0027] The second lead wires 19 are wiring materials for outputting power from the back-side solar cells 15. The second lead wires 19 extend from both electrical ends of the connector of the back-side solar cells 15 and extend to the outside through the back-side through-holes 131. The second lead wires 19 can be formed from the same conductive material as the first lead wires 18.

[0028] The encapsulant 20 is filled between the front surface protective material 11 and the intermediate protective material 12 and between the intermediate protective material 12 and the back surface protective material 13, that is, in the space around the thin-film solar cells 14 and the space around the back surface solar cells 15. The encapsulant 20 bonds the front surface protective material 11, the thin-film solar cells 14, the intermediate protective material 12, the back surface solar cells 15, and the back surface protective material 13 together, and prevents moisture and the like from coming into contact with the thin-film solar cells 14 and the back surface solar cells 15. Suitable examples of the encapsulant 20 include translucent resins such as ethylene / vinyl acetate copolymer (EVA), ethylene / α-olefin copolymer, ethylene / vinyl acetate / triallyl isocyanurate (EVAT), polyvinyl butyrate (PVB), acrylic resin, urethane resin, and silicone resin. The encapsulant 20 is preferably formed from a material that has thermoplasticity that allows it to fluidize and penetrate into gaps between components and minute recesses in the thin-film solar cells 14 and back-side solar cells 15 during the manufacturing stage of the solar cell module 1 (during heat pressing), and that loses its thermoplasticity in the final product and can maintain its shape even when the temperature of the solar cell module 1 rises. In other words, the encapsulant 20 is preferably formed from a resin composition that is primarily 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. It is also preferable to place small pieces of the material that forms the encapsulant 20 inside the enclosed moisture-proof material 17 and then heat-press the material so that the enclosed moisture-proof material 17 can be sufficiently filled with the encapsulant 20.

[0029] The solar cell module 1 having the above configuration does not directly seal the intermediate through hole 121 through which the first lead wire 18 passes, but rather airtightly connects the intermediate protective material 12 around the intermediate through hole 121 and the back surface protective material 13 with an annular surrounding moisture-proof material 17, thereby sealing the small space including the intermediate through hole 121 and preventing moisture from entering around the intermediate through hole 121. This increases the contact area of ​​the surrounding moisture-proof material 17 with the intermediate protective material 12 and the back surface protective material 13, reliably preventing the formation of gaps through which moisture can enter and more effectively suppressing moisture-induced deterioration of the thin-film solar cells 14.

[0030] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and various modifications and variations are possible. For example, in the solar cell module according to the present invention, the light-shielding layer and the rear-side solar cell may have any configuration. Furthermore, to improve the design, the solar cell module according to the present invention may use a printed rear surface protective material or may have a design film disposed between the intermediate protective material and the rear-side solar cell.

[0031] REFERENCE SIGNS LIST 1 Solar cell module 11 Surface protective material 111 Light-shielding layer 12 Intermediate protective material 121 Intermediate through-hole 13 Back surface protective material 131 Back-side through-hole 14 Thin-film solar cell 15 Back-side solar cell 16 Peripheral moisture-proof material 17 Surrounding moisture-proof material 18 First lead wire 19 Second lead wire 20 Sealant

Claims

1. A solar cell module comprising: a surface protective material; an intermediate protective material arranged on the back side of the surface protective material and having an intermediate through hole; a back protective material arranged on the back side of the intermediate protective material; thin-film solar cells arranged between the surface protective material and the intermediate protective material; an enclosed moisture-proof material arranged in a ring shape surrounding the intermediate through hole and sandwiched between the intermediate protective material and the back protective material; lead wires extending from the thin-film solar cells, passing through the intermediate through hole, and penetrating the enclosed moisture-proof material from the inside to the outside; and a sealing material filled between the surface protective material and the intermediate protective material and between the intermediate protective material and the back protective material.

2. The solar cell module according to claim 1, wherein the lead wires pass through the rear surface protective material outside the surrounding moisture-proof material in a plan view.

3. The solar cell module according to claim 1 or 2, further comprising a rear solar cell arranged between the intermediate protective material and the rear surface protective material so as not to overlap with the surrounding moisture-proof material in a planar view.

4. The solar cell module according to claim 1 or 2, wherein the surface protection material has a light-shielding layer on the outer periphery, and the surrounding moisture-proof material is encompassed by the light-shielding layer in plan view.

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