Solar battery module

Abstract

A solar battery module (1) comprises: a front surface protective material (10); solar battery cells (20) disposed on the back side of the front surface protective material (10); a back surface protective material (30) disposed on the back side of the solar battery cells (20) and having through holes (31); metal sheets (40) disposed between solar battery cells (20) and the back surface protective material (30) so as to respectively cover the through holes (31); internal moisture-proof adhesives (50) respectively disposed at least in regions surrounding the through holes (31) in plan view between the back surface protective material (30) and the metal sheets (40) so as to come into close contact with the back surface protective material (30) and the respective metal sheets (40); and lead wires (70) each extending from a solar battery cell (20), extending through an internal moisture-proof adhesive (50) by penetrating the internal moisture-proof adhesive (50) or by passing through a metal sheet (40) in a cross-sectional view, and extending from the back side of the back surface protective material (30) through a through hole (31).

Description

Solar cell module

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

[0002] A solar cell module in which solar cells are sealed between plate-shaped protective members is in use. The solar cell module may be configured such that lead wires for outputting electric power from the solar cells extend to the outside through through-holes formed in a back protective member. In order to prevent moisture from penetrating into the inside of the solar cell module, it has been proposed to fill a filler into the through-hole through which the lead wire passes (see, for example, Patent Document 1).

[0003] Japanese Unexamined Patent Application Publication No. 2011-124435

[0004] Even when the filler is filled into the through-hole of the protective member, the distance for blocking the moisture intrusion path is small, and a sufficient moisture-proof effect cannot be obtained. In addition, when an external force acts on the lead wire, stress acts on the filler, causing the filler to peel off from the protective member, which may further reduce moisture resistance. In particular, thin-film solar cells such as perovskite solar cells are easily degraded by moisture. Accordingly, an object of the present invention is to provide a solar cell module capable of suppressing degradation of solar cells caused by moisture.

[0005] (1) A solar cell module according to one aspect of the present invention includes: a front surface protective member; a solar cell disposed on a back side of the front surface protective member; a back surface protective member disposed on a back side of the solar cell and having a through-hole; a metal sheet disposed between the solar cell and the back surface protective member so as to cover the through-hole; an internal moisture-proof adhesive disposed in a region surrounding the through-hole at least in a plan view between the back surface protective member and the metal sheet, the internal moisture-proof adhesive being in close contact with the back surface protective member and the metal sheet; and a lead wire extending from the solar cell, penetrating the internal moisture-proof adhesive in a cross-sectional view or extending inside the internal moisture-proof adhesive via the metal sheet, and extending to a back side of the back surface protective member through the through-hole.

[0006] (2) In the solar cell module according to (1), the metal sheet may be integrally formed with a portion of the lead wire on the solar cell side.

[0007] (3) In the solar cell modules of (1) to (2), the metal sheet may be a metal film formed on a resin film.

[0008] (4) The solar cell modules of (1) to (3) may further include an insulating sheet between the solar cell and the metal sheet, which is positioned to cover the metal sheet.

[0009] (5) In the solar cell module of (4), the metal sheet and the insulating sheet may be a single laminated sheet.

[0010] (6) In the solar cell modules of (1) to (5), the width of the internal moisture-proof adhesive may be 10 mm or more.

[0011] (7) In the solar cell modules of (1) to (6), the internal moisture-proof adhesive may be formed from a butyl rubber-based thermoplastic adhesive.

[0012] (8) The solar cell modules of (1) to (7) may further include an outer moisture-proof adhesive that connects the outer periphery of the surface protective material and the back protective material.

[0013] According to the present invention, a solar cell module can be provided that can suppress the degradation of solar cells due to moisture.

[0014] This is a schematic cross-sectional view of a solar cell module according to the first embodiment of the present invention. This is a schematic cross-sectional view of a solar cell module according to the second embodiment of the present invention.

[0015] Embodiments of the present invention will be described below with reference to the drawings. The dimensions of various components in the drawings have been adjusted for ease of viewing. Furthermore, in embodiments described later, the same reference numerals are used for components identical to those described in earlier embodiments, and redundant explanations may be omitted.

[0016] [First Embodiment] Figure 1 is a schematic cross-sectional view of a solar cell module 1 according to the first embodiment of the present invention. The solar cell module 1 comprises a surface protective material 10, a solar cell 20, a back protective material 30, a metal sheet 40, an internal moisture-proof adhesive 50, an insulating sheet 60, a lead wire 70, an outer moisture-proof adhesive 80, and a sealing material 90.

[0017] The surface protection material 10 protects the solar cell 20 by covering its front surface via the sealing material 90. The surface protection material 10 can be formed from a plate-shaped or sheet-shaped material, and preferably has excellent light transmission, water-blocking properties, scratch resistance, and weather resistance. Specifically, the material of the surface protection material 10 can be a transparent resin such as acrylic resin or polycarbonate resin, or glass, with glass being particularly preferred. Furthermore, the surface of the surface protection material 10 may be processed to have an uneven surface or covered with an anti-reflective coating layer to suppress light reflection.

[0018] The solar cell 20 is placed on the back side of the surface protective material 10. The solar cell 20 absorbs light and converts it into electricity. The solar cell 20 is not particularly limited, but when it has a thin-film photoelectric conversion layer, especially a perovskite photoelectric conversion layer, the effect of preventing moisture from entering the inside of the solar cell module 1 by the present invention is particularly significant. For example, the solar cell 20 may be a monolithic tandem type solar cell in which a perovskite photoelectric conversion layer is laminated on the surface of a crystalline silicon photoelectric conversion substrate. The perovskite compound that forms the main body of the perovskite photoelectric conversion layer includes an organic atomic group A containing at least one of monovalent organic ammonium ions and amidinium-based ions, a metal atom B that generates a divalent metal ion, and a halogen atom X containing at least one of iodide ions I, bromide ions Br, chloride ions Cl, and fluoride ions F, and ABX ３ Compounds represented by can be used. Perovskite compounds in which some or all of the organic atomic group A is substituted with alkali metal Am are also not excluded from the present invention.

[0019] The back surface protective material 30 is positioned on the back side of the solar cell 20, facing the front surface protective material 10. The back surface protective material 30 protects the solar cell 20 by covering its back side. The back surface protective material 30 has through holes 31 through which the lead wires 70 pass. The back surface protective material 30 can be formed from a plate-shaped or sheet-shaped material, and preferably has excellent water-impermeable properties. The back surface protective material 30 can be formed from the same material as the front surface protective material 10, or from a composite material of the same material and a metal layer that improves water-impermeable properties.

[0020] The metal sheet 40 may be formed from a metal foil or a gold side plate, or it may be a metal film formed on a resin film. The metal sheet 40 is positioned between the solar cell 20 and the back protective material 30 so as to cover the through hole 31. The metal sheet 40 prevents moisture from entering through the through hole 31 and moving towards the solar cell 20. The planar shape of the metal sheet 40 is not particularly limited and can be circular, rectangular, etc. The metal used to form the metal sheet 40 can be any metal with stability, such as copper, aluminum, or stainless steel. The thickness of the metal sheet 40 may be between 5 μm and 500 μm, depending on the material.

[0021] The internal moisture-proof adhesive 50 is arranged in close contact with the back protective material 30 and the metal sheet 40, at least in the area surrounding the through-hole 31 in a plan view between the back protective material 30 and the metal sheet 40. Specifically, the internal moisture-proof adhesive 50 may be arranged in a closed annular shape surrounding the through-hole 31, or it may be arranged continuously on the front side of the back protective material 30 around the through-hole 31. The internal moisture-proof adhesive 50 prevents moisture from entering the inside of the solar cell module 1 by sealing the gap between the back protective material 30 and the metal sheet 40 around the through-hole 31. A thermoplastic adhesive that can be easily adhered to the back protective material 30 and the metal sheet 40 is preferably used as the internal moisture-proof adhesive 50, and among these, a butyl rubber-based thermoplastic adhesive that has excellent moisture resistance and a relatively high melt flow rate so as not to be washed away by the sealing material 90 during the assembly of the solar cell module 1 is particularly preferred. The internal moisture-proof adhesive 50 may also contain hygroscopic particles. Suitable hygroscopic particles for the internal moisture-proof adhesive 50 include, for example, silica gel, alumina, zeolite, and talc. The width of the internal moisture-proof adhesive 50 (average transverse distance from the inside to the outside) is preferably 10 mm to 20 mm in order to reliably block moisture. The internal moisture-proof adhesive 50 can be formed by stacking two sheet-like materials so as to sandwich the leader wires 70 at least around the outer periphery during the assembly of the solar cell module 1. The back sheet-like material is provided with an opening or slit through which the leader wires 70 pass.

[0022] The insulating sheet 60 is positioned between the solar cell 20 and the metal sheet 40, covering the metal sheet 40, and insulating the space between the solar cell 20 and the metal sheet 40. The insulating sheet 60 may be a laminated sheet integral with the metal sheet 40. However, it is preferable that the insulating sheet 60 be formed slightly larger than the metal sheet 40 (i.e., partially laminated with the metal sheet 40) to ensure sufficient insulation distance between the solar cell 20 and the metal sheet 40, in order to prevent leakage current from occurring between the solar cell 20 and the lead wire 70 through the metal sheet 40 when the metal sheet 40 comes into contact with the lead wire 70. The insulating sheet 60 can be formed from an insulating sheet or film material. Examples of materials for forming the insulating sheet 60 include polyethylene terephthalate (PET), polyethylene (PE), polyamide (PA), polyimide (PI), fluororesin, silicone resin, and other resins. The metal sheet 40 and the insulating sheet 60 may be provided as a composite material.

[0023] The lead wire 70 is a wiring material for outputting power from the solar cell 20, extending from the solar cell 20, penetrating the internal moisture-proof adhesive 50 in cross-sectional view, and extending to the back side of the back surface protective material 30 through the through hole 31. The lead wire 70 is preferably formed from a single metal conductor, and more preferably from a strip-shaped metal conductor, so as not to form a gap between it and the internal moisture-proof adhesive 50. To eliminate pathways for moisture to enter, it is preferable that the lead wire 70 is not covered at least in the portion that penetrates the internal moisture-proof adhesive 50.

[0024] The outer moisture-proof adhesive 80 is placed on the outer periphery between the surface protective material 10 and the back protective material 30, connecting the outer peripheries of the surface protective material 10 and the back protective material 30 and sealing the gap. The same adhesive as the internal moisture-proof adhesive 50 can be used as the outer moisture-proof adhesive 80.

[0025] The sealing material 90 is filled between the surface protective material 10 and the back protective material 30, that is, in the space around the solar cell 20. The sealing material 90 adheres the surface protective material 10, the solar cell 20, and the back protective material 30, and also prevents moisture and other substances from coming into contact with the solar cell 20. Suitable sealing materials for 90 include, for example, 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, or silicone resin. Preferably, the sealing material 90 is made of a material that has thermoplastic properties that allow it to flow and enter the gaps between components and the fine recesses of the solar cell 20 during the manufacturing stage (hot pressing) of the solar cell module 1, and that can maintain its shape even when the temperature of the solar cell module 1 rises by losing its thermoplastic properties in the final product. In other words, it is preferable that the sealing material 90 is formed from a resin composition mainly consisting of a thermoplastic resin and containing a crosslinking agent that is activated at a temperature higher than the softening point of the thermoplastic resin and causes the thermoplastic resin to crosslink and harden.

[0026] In the solar cell module 1 having the above configuration, instead of directly sealing the through-hole 31 through which the lead wire 70 passes, the internal moisture-proof adhesive 50 is used to airtightly connect the metal sheet 40 covering the through-hole 31 and the back surface protective material 30, thereby sealing the entry route for moisture through the through-hole 31. As a result, the contact area of ​​the internal moisture-proof adhesive 50 with the back surface protective material 30 and the metal sheet 40 is large, reliably preventing the formation of gaps through which moisture can enter, and suppressing the deterioration of the solar cell 20 due to moisture.

[0027] [Second Embodiment] Figure 2 is a schematic cross-sectional view of a solar cell module 1A according to the second embodiment of the present invention. The solar cell module 1 comprises a surface protective material 10, a solar cell 20, a back protective material 30, a metal sheet 40A, an internal moisture-proof adhesive 50, an insulating sheet 60, a lead wire 70A, an outer moisture-proof adhesive 80, and a sealing material 90.

[0028] In this embodiment, the lead wire 70A extends inside the internal moisture-proof adhesive 50 via the metal sheet 40A. In other words, in this embodiment, the metal sheet 40A connects the portion of the lead wire 70A that extends into the sealing material 90 on the solar cell 20 side and the portion that extends to the outside through the through hole 31, forming part of the circuit for outputting current from the solar cell 20. In the illustrated embodiment, the metal sheet 40A and the portion of the lead wire 70A that extends into the solar cell 20 side are cut from a single metal sheet and formed integrally. The portion of the lead wire 70A that penetrates the through hole 31 is prepared separately from the metal sheet 40A and connected to the back surface of the metal sheet 40A inside the internal moisture-proof adhesive 50. The connection between the metal sheet 40A and the lead wire 70A may be made using a conductive adhesive, solder, etc., or by ultrasonic welding, etc., or a structure may be provided that presses the lead wire 70A against the metal sheet 40A by elastic force, etc.

[0029] In this embodiment, the solar cell module 1A has higher airtightness because the lead wires 70 do not penetrate the internal moisture-proof adhesive 50, and the degradation of the solar cells 20 due to moisture intrusion can be more reliably suppressed.

[0030] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications and variations are possible. For example, in a solar cell module according to the present invention, when the lead wires extend inside the internal moisture-proof adhesive via a metal sheet, the portion of the lead wire on the solar cell side and the portion extending outward from the through hole may be formed separately on the metal sheet and joined to the metal sheet, respectively. The solar cell module according to the present invention may be configured to have multiple lead wires extending from a single through hole. Furthermore, in a solar cell module according to the present invention, the outer moisture-proof adhesive is not an essential component, and the insulating sheet can also be omitted if the through hole and metal sheet are provided in a position that does not overlap with the solar cell in a plan view.

[0031] 1.1A Solar cell module 10 Surface protective material 20 Solar cell 30 Back protective material 31 Through hole 40.40A Metal sheet 50 Internal moisture-proof adhesive 60 Insulating sheet 70.70A Lead wire 80 Outer moisture-proof adhesive 90 Sealing material

Claims

1. A solar cell module comprising: a surface protective material; a solar cell disposed on the back side of the surface protective material; a back protective material disposed on the back side of the solar cell and having through holes; a metal sheet disposed between the solar cell and the back protective material so as to cover the through holes; an internal moisture-proof adhesive disposed in close contact with the back protective material and the metal sheet in at least the region surrounding the through holes in a plan view between the back protective material and the metal sheet; and a leader line extending from the solar cell, penetrating the internal moisture-proof adhesive or extending inside the internal moisture-proof adhesive through the metal sheet in a cross view, and extending to the back side of the back protective material through the through holes.

2. The solar cell module according to claim 1, wherein the metal sheet is formed integrally with the portion of the lead wire that is on the solar cell side.

3. The solar cell module according to claim 1 or 2, wherein the metal sheet is a metal film formed on a resin film.

4. The solar cell module according to claim 1 or 2, further comprising an insulating sheet disposed between the solar cell and the metal sheet so as to cover the metal sheet.

5. The solar cell module according to claim 4, wherein the metal sheet and the insulating sheet are a single laminated sheet.

6. The solar cell module according to claim 1 or 2, wherein the width of the internal moisture-proof adhesive is 10 mm or more.

7. The solar cell module according to claim 1 or 2, wherein the internal moisture-proof adhesive is formed from a butyl rubber-based thermoplastic adhesive.

8. The solar cell module according to claim 1 or 2, further comprising an outer moisture-proof adhesive for connecting the outer periphery of the surface protective material and the outer periphery of the back protective material.

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