JP2014068006A - Solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell module which prevents peeling between an electric wire and solar cells and disconnection of the electric wire when the solar cell module is enlarged and has high durability against temperature changes in a used environment.SOLUTION: A photoelectric conversion layer includes two or more solar cells which are connected by a reinforcement layer and an electric wire. A solar cell module is formed by laminating the photoelectric conversion layer between a surface protection layer and a rear surface protection layer. In the solar cell module, the electric wire is arranged at the inner side of a peripheral part of a lamination surface (a surface perpendicular to a lamination direction) of the reinforcement layer.

Description

  The present invention relates to a solar cell module.

As a solar cell, for example, a solar cell using single crystal silicon or polycrystalline silicon is known.
These solar cells normally constitute a solar cell module in a state of being sealed between protective members (protective layer) with a sealing material such as EVA resin. Specifically, these solar cell modules sandwich a photoelectric conversion layer in which a plurality of solar cells are connected with an electric wire or the like between protective layers such as a surface protective layer and a back surface protective layer, wrapped in an EVA resin film, Generally, the entire module is vacuum-produced by heating and pressing with a vacuum laminator.

In recent years, polycarbonate resin has been adopted as a material for the protective layer in order to reduce the weight of the solar cell module and improve the transparency and mechanical strength. For example, in Patent Document 1, a polycarbonate resin is used for the protective layer, and an acrylic resin, a polyvinyl fluoride resin (PVF), a polyfluorinated resin is further provided as a soft resin protective layer between the protective layer and the photoelectric conversion layer. By providing a soft resin protective layer such as vinylidene resin, the internal thermal stress of the polycarbonate generated in the photoelectric conversion layer by removing the sealing material is removed, and the solar cell module that is lightweight with little deformation and excellent in impact resistance It is described that it is obtained.

JP 2002-1111014 A

  The photoelectric conversion layer of the solar cell module is mainly composed of a plurality of solar cells connected by electric wires, but the electric wires are wired on the current collecting electrode and are connected from the wiring to the external connector through the bus bar. From there, the electric power generated by the solar cells is taken out. The wiring pattern of these current collectors, interconnectors and bus bars can be determined in advance by the position of the external connector (junction box). Although the above-mentioned Patent Document 1 does not particularly mention the influence on the bus bar and the interconnector when the solar cell module is used in an environment with a large temperature change, according to the present inventors, the solar cell module has a large size. When the bus bar or interconnector length increases or the number of wires increases, a buffer layer such as a soft resin protective layer can relieve the internal thermal stress of the protective layer on the interconnector or bus bar. It was found that there was a part that could not be broken, and the breakage occurred due to the thermal stress of the polycarbonate at that part.

In particular, by using a resin such as polycarbonate as a protective layer, the module can be reduced in weight.
The present invention solves the above-mentioned problems, and when a solar cell module is enlarged, peeling between the electric wire and the solar cell and disconnection of the electric wire do not occur, and the solar cell having high durability against the use environment The problem is to provide a module.

As a result of intensive studies to solve the above problems, the present inventors have made the reinforcing layer area larger than the area of the laminated surface of the photoelectric conversion layer, and the wiring of the wires such as the interconnector and the bus bar is the reinforcing layer. The present invention is completed by finding that the wiring inside the peripheral portion of the laminated surface (the surface perpendicular to the laminating direction) can suppress the disconnection of the interconnector and bus bar existing in the peripheral portion of the photoelectric conversion layer. It came to.

That is, the gist of the present invention resides in the following [1] to [7].
[1] A photoelectric conversion layer including two or more solar cells connected by a reinforcing layer and an electric wire is laminated between the front surface protective layer and the rear surface protective layer, and the electric wire is a laminated surface of the reinforcing layer ( A solar cell module wired inside the peripheral edge of the surface perpendicular to the stacking direction.
[2] The solar cell module according to [1], in which a surface protective layer, a photoelectric conversion layer, a reinforcing layer, and a back surface protective layer are laminated in this order from the sunlight receiving surface side.
[3] The solar cell module according to [2], further including a reinforcing layer between the photoelectric conversion layer and the surface protective layer.
[4] The solar cell module according to any one of [1] to [3], wherein a Young's modulus at 23 ° C. of the reinforcing layer is 2 GPa or more and 300 GPa or less.
[5] The solar cell module according to any one of [1] to [4], wherein the material of the reinforcing layer is metal or glass.
[6] The solar cell module according to any one of [1] to [5], wherein the surface protective layer and the back surface protective layer have a linear expansion coefficient at −30 ° C. to 30 ° C. of 30 ppm or more.
[7] The solar cell module according to any one of [1] to [6], wherein the reinforcing layer has a thickness of 15 μm or more and 2000 μm or less.

  If the solar cell module of the present invention, it is possible to reduce the breakage of the electric wires (bus bars and interconnectors) due to the influence of internal stress generated by expansion and contraction of the back surface protective layer and the surface protective layer in an environment with a large temperature change, Durability against electrical characteristics can be maintained. Moreover, when it is set as the module array which connected the solar cell module of this invention two or more in series and in parallel, the damage of the module by the reverse bias generate | occur | produced between solar cell modules can be prevented.

It is a figure which shows the wiring of the solar cell submodule contained in the solar cell module of this invention (Example 1). It is a figure which shows the wiring of the solar cell submodule contained in the conventional solar cell module (comparative example 1). BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram (cross-sectional view) which shows the embodiment of the solar cell module of this invention (Example 1). It is a schematic diagram (cross-sectional view) which shows the embodiment of a solar cell module (comparative example 1).

Embodiments of the solar cell module of the present invention will be specifically described below.
<Surface protective layer>
The surface protective layer of the solar cell module of the present invention is a layer for imparting mechanical strength, weather resistance, scratch resistance, chemical resistance, gas barrier properties and the like to the solar cell module. As the surface protective layer, a resin (hereinafter sometimes referred to as “resin (A)”) is used. From the viewpoint of supplying a large amount of sunlight to the photoelectric conversion layer, the total light transmittance of the resin (A) is 80% or more, preferably 90% or more. The measuring method of a total light transmittance is based on JISK7361-1, for example.

Examples of the resin (A) used for the surface protective layer include acrylic resins such as polycarbonate (PC) and polymethyl methacrylate (PMMA), cyclic polyolefin, polystyrene, polyethylene terephthalate (PET), and ethylene-tetrafluoroethylene copolymer ( ETFE), polytetrafluoroethylene (PTFE), polypropylene (PP), polyethylene (PE) and the like. Preferred are polycarbonate (PC) resin, acrylic resin such as polymethyl methacrylate (PMMA), and ethylene-tetrafluoroethylene copolymer (ETFE), and particularly preferred are polycarbonate (PC) resin and polymethyl methacrylate (PMMA). Acrylic resin.

  Further, the linear expansion coefficient of the resin (A) at −30 to 30 ° C. is not particularly limited, but is preferably 30 ppm / K or more, more preferably 45 ppm / K or more, and further preferably 50 ppm / K or more. It is. The linear expansion coefficient is measured by, for example, ASTM D696. If the linear expansion coefficient is less than 30 ppm / K, thermal expansion / contraction stress that requires a reinforcing layer tends not to occur. On the other hand, the upper limit is not particularly limited, but is usually 200 ppm / K or less, preferably 100 ppm / K or less.

  Further, the Young's modulus at 23 ° C. of the resin (A) is not particularly limited, but is preferably 10 GPa or less, more preferably 8 GPa or less, and further preferably 6 GPa or less. Examples of the Young's modulus measurement method include JIS K7161-1994 (plastic tensile modulus), JIS K7113 (plastic tensile test method), static test method (Ewing method), and the like. If the Young's modulus exceeds 5 GPa, the heat shrinkage stress tends to be excessive. On the other hand, the lower limit is not particularly limited, but is usually larger than 0 GPa and preferably 1 GPa or more.

The method for obtaining these resins is not particularly limited, and commercially available products can be used. Examples of polycarbonate include polycarbonate plates manufactured by Takiron Co., Ltd., Iupilon manufactured by Mitsubishi Engineering Plastics Co., Ltd., and polymethyl methacrylate such as acrylite manufactured by Mitsubishi Rayon Co., Ltd. and Sumipex manufactured by Sumitomo Chemical Co., Ltd.
Moreover, it does not specifically limit as glass transition temperature (Tg) of resin (A), For example, it is preferable that it is 150 degrees C or less, and it is more preferable that it is 140 degrees C or less. Moreover, it is preferable that Tg of resin is 70 degreeC or more, and it is preferable that it is 80 degreeC or more. When Tg is in the above range, the solar cell module has an appropriate flexibility during lamination and excellent workability. The glass transition point Tg can be measured by DSC measurement.

  Moreover, although it does not specifically limit as a weight average molecular weight (Mw) in case resin (A) is a high molecular weight body, For example, 10,000 or more are preferable. The upper limit is 70,000 or less, and preferably 20,000 or less. The weight average molecular weight in the present invention is determined by SEC (size exclusion chromatography) measurement. In SEC measurement, the elution time is shorter for higher molecular weight components and the elution time is longer for lower molecular weight components, but using the calibration curve calculated from the elution time of polystyrene (standard sample) with a known molecular weight, the elution time of the sample is changed to the molecular weight. The weight average molecular weight is calculated by conversion.

  Although the thickness of a surface protective layer is not specifically limited, Preferably it is 3.0 mm or more, More preferably, it is 3.5 mm or more, More preferably, it is 4 mm or more, Most preferably, it is 5 mm or more. The larger this value, the higher the sound insulation and the higher the impact resistance. On the other hand, the upper limit is not particularly limited, but is preferably less than 8 mm, more preferably less than 7 mm. If the surface protective layer is too thick, the flexibility is reduced and the weight of the module is increased, so that the merit of using the solar cell module substrate as a resin is lost. Necessary for suppressing deterioration of each interface such as peeling between the surface protective layer and the sealing layer in an outdoor environment by cutting ultraviolet rays of a wide wavelength in the surface protective layer and obtaining a heat ray shielding effect. Depending on the case, an ultraviolet absorber (sometimes referred to as “UV absorber”) may be included.

  Specific examples of the UV absorber include benzophenone compounds such as 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and 2-hydroxy-4-benzyloxy. Benzophenone, 2-hydroxy-4-methoxy-5-sulfoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4 , 4′-dimethoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxy-5-sodiumsulfoxybenzophenone, bis (5-benzoyl-4-hydroxy-2-methoxyphenyl) methane, 2-hydroxy- 4-n-dodecyloxybenzophenone, Beauty and 2-hydroxy-4-methoxy-2'-carboxy benzophenone may be exemplified.

  Specifically, in the benzotriazole series, for example, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2- (2- Hydroxy-3,5-dicumylphenyl) phenylbenzotriazole, 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2,2'-methylenebis [4- (1 , 1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol], 2- (2-hydroxy-3,5-di-tert-butylphenyl) benzotriazole, -(2-hydroxy-3,5-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy -3,5-di-tert-amylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-butylphenyl) benzotriazo- 2- (2-hydroxy-4-octoxyphenyl) benzotriazole, 2,2'-methylenebis (4-cumyl-6-benzotriazolephenyl), 2,2'-p-phenylenebis (1,3 -Benzoxazin-4-one), and 2- [2-hydroxy-3- (3,4,5,6-tetrahydrophthalimidomethyl) -5-methylphenyl] benzotriazole, and 2- (2'-hydroxy) -5-Methacryloxyethylphenyl) -2H-benzotriazole and vinyl monomer copolymerizable with the monomer 2-hydroxyphenyl-2H, such as a copolymer of 2- (2′-hydroxy-5-acryloxyethylphenyl) -2H-benzotriazole and a vinyl monomer copolymerizable with the monomer Examples include polymers having a benzotriazole skeleton.

  In the hydroxyphenyl triazine series, for example, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-hexyloxyphenol, 2- (4,6-diphenyl-1,3,5) -Triazin-2-yl) -5-methyloxyphenol, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-ethyloxyphenol, 2- (4,6-diphenyl) -1,3,5-triazin-2-yl) -5-propyloxyphenol and 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-butyloxyphenol Illustrated. Furthermore, the phenyl group of the above exemplary compounds such as 2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl) -5-hexyloxyphenol is 2,4-dimethyl. Examples of the compound are phenyl groups.

In the cyclic imino ester system, for example, 2,2′-p-phenylenebis (3,1-benzoxazin-4-one), 2,2′-m-phenylenebis (3,1-benzoxazin-4-one) And 2,2′-p, p′-diphenylenebis (3,1-benzoxazin-4-one) and the like.
In the case of cyanoacrylate, for example, 1,3-bis-[(2′-cyano-3 ′, 3′-diphenylacryloyl) oxy] -2,2-bis [(2-cyano-3,3-diphenylacryloyl) oxy ] Methyl) propane, and 1,3-bis-[(2-cyano-3,3
-Diphenylacryloyl) oxy] benzene and the like.

  A polymer obtained by copolymerizing such a UV-absorbing monomer and / or light-stable monomer and a monomer such as alkyl (meth) acrylate by taking the structure of a monomer compound capable of radical polymerization. It may be a type of ultraviolet absorber. Preferred examples of the ultraviolet absorbing monomer include compounds containing a benzotriazole skeleton, a benzophenone skeleton, a triazine skeleton, a cyclic imino ester skeleton, and a cyanoacrylate skeleton in the ester substituent of (meth) acrylic acid ester. The

  Among them, benzotriazole and hydroxyphenyltriazine are preferable in terms of ultraviolet absorption ability, and cyclic imino ester and cyanoacrylate are preferable in terms of heat resistance and hue. You may use the said ultraviolet absorber individually or in mixture of 2 or more types. Noacrylates are preferred. You may use the said ultraviolet absorber individually or in mixture of 2 or more types.

  The compounding quantity of a ultraviolet absorber is 0.01-0.5 weight part with respect to 100 weight part of resin components, More preferably, it is 0.02-0.4 weight part, More preferably, it is 0.03-0. 35 parts by weight, particularly preferably 0.05 to 0.3 parts by weight. Above the upper limit of the above preferable range, the initial hue (YI value) of the molded product becomes high, which is not preferable. In addition, the weather resistance is not sufficiently exhibited below the lower limit of the preferred range.

  Moreover, in the solar cell module of this invention, you may provide a surface protection sheet further in the outer side (sunlight side) of a surface protection layer. In the present invention, it is preferable to provide a surface protective sheet in order to suppress damage and deterioration of the surface protective layer and maintain the total light transmittance. The material constituting the surface protective sheet is preferably a weather-resistant film, and commonly used known materials can be used.

  Examples of the resin used as the material for the weather resistant film include ethylene-tetrafluoroethylene copolymer, silicone, acrylate, methacrylate, polyethylene terephthalate, and polyamide. Among these, an ethylene-tetrafluoroethylene copolymer is preferable from the viewpoint of weather resistance. Also, silicone and acrylate are preferable from the viewpoint of scratch resistance.

The thickness of the weather-resistant protective film is not particularly limited, but is usually 10 μm or more, preferably 20 μm or more, and usually 200 μm or less, preferably 150 μm or less.
An adhesive layer may be provided between the surface protective sheet and the surface protective layer. The material of the adhesive layer is not particularly limited, but usually, for example, ethylene-vinyl acetate copolymer (EVA) resin, polyvinyl butyral (PVB) resin, modified polyethylene resin modified with maleic acid or silane, modified polypropylene resin, Light transmissive materials such as epoxy adhesives and urethane adhesives are used. The thickness of the adhesive layer is not particularly limited, but a sheet shape of, for example, 300 to 500 μm is preferable.

<Photoelectric conversion layer>
The photoelectric conversion layer of the solar cell module of the present invention is a layer having solar cells that can directly convert light energy into electric power, and is usually formed by connecting a plurality of solar cells with electric wires or the like. Electricity generated in the solar battery cell can be taken out via an external converter through an electric wire.

As a solar cell element, a silicon solar cell element such as a single crystal silicon solar cell element, a polycrystalline silicon solar cell element, an amorphous silicon solar cell element, a microcrystalline silicon solar cell element, a spherical silicon solar cell element, or the like is used. Can do. Moreover, compound solar cell elements, such as a CIS type solar cell element, a CIGS type solar cell element, and a GaAs type solar cell element, can also be adopted. Further, a dye-sensitized solar cell element, an organic thin film solar cell element, a multi-junction solar cell element, a HIT solar cell element, or the like may be employed.

  For example, the silicon-based solar cell element may be a commercially available one, and examples thereof include solar cells manufactured by JA Solar, Inley Green Energy, Sharp, Kyosemi, and Fuji Electric.

Each electrode of the element of the solar battery cell can be formed using one or more arbitrary materials having conductivity. Examples of the electrode material (electrode constituent material) include metals such as platinum, gold, silver, aluminum, chromium, nickel, copper, titanium, magnesium, calcium, barium, sodium, and alloys thereof; indium oxide and tin oxide Metal oxides such as, or alloys thereof (ITO: indium tin oxide); conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene; acids such as hydrochloric acid, sulfuric acid, sulfonic acid, Lewis acids such as FeCl ₃ , halogen atoms such as iodine, sodium,
Examples include those containing a dopant such as a metal atom such as potassium; conductive composite materials in which conductive particles such as metal particles, carbon black, fullerene, and carbon nanotubes are dispersed in a matrix such as a polymer binder.

The thickness of each electrode and the thickness of the photoelectric conversion layer can be determined based on the required output and the like.
Further, an auxiliary electrode may be provided so as to be in contact with the electrode. In particular, it is effective when using a slightly conductive electrode such as ITO. As the auxiliary electrode material, the same material as the above metal material can be used as long as the conductivity is good, but silver, aluminum, and copper are exemplified.

  The present invention is characterized by a method of handling a bus bar and an interconnector used in the photoelectric conversion layer of the solar cell module of the present invention. In the present invention, the solar battery cell is connected to the collector electrode on the solar battery cell by an electric wire (interconnector) with solder or a conductive adhesive. Furthermore, the bus bar connects the ends of the positive and negative electrodes of the plurality of wired solar cells to the junction box.

  The “peripheral portion” as used in the present invention is defined with respect to the front surface protective layer, the back surface protective layer and the reinforcing layer, and the peripheral portion of the laminated surface (surface perpendicular to the lamination direction) of the front surface protective layer and the back surface protective layer. , The edge of the solar cell module is 4mm or less from the solar light receiving surface, and the peripheral edge of the laminated surface of the reinforcing layer is 15mm or more from the four sides. That is. At this time, by interconnecting the interconnector and the bus bar inside the peripheral portion of the reinforcing layer laminated surface (surface perpendicular to the laminating direction), the photoelectric conversion layer of the photoelectric conversion layer due to the expansion and contraction of the substrate having a high linear expansion coefficient and elastic modulus is obtained. The disconnection of the interconnector and bus bar existing at the peripheral edge can be suppressed. It is preferable that the interconnector and the bus bar exist inside the peripheral edge of the laminated surface of the reinforcing layer. There exists a tendency which can suppress the bubble generation | occurrence | production of an edge part by wiring inside the peripheral part of the laminated surface of a surface protective layer and / or a back surface protective layer as the said range. Moreover, there exists a tendency which can suppress the wave | undulation of an electric wire by making the peripheral part of the lamination | stacking surface of a reinforcement layer into the said range, and wiring inside it. The number of solar cells connected by electric wires (interconnectors) included in the photoelectric conversion layer in the solar cell module of the present invention is 2 or more, preferably 3 or more, more preferably 4 or more. In addition, a large sized solar cell module says that the number of this photovoltaic cell is 3 or more normally.

<Back side protective layer>
As the back surface protective layer of the solar cell module of the present invention, glass or resin (hereinafter “resin (B
May be referred to as “)”), but a resin is preferably used.
Examples of such a resin (B) include polycarbonate (PC) resin, polymethyl methacrylate (PMMA), glass epoxy multilayer material, fiber reinforced plastic (FRP), cyclic polyolefin, polystyrene, polyethylene terephthalate (PET), and the like. It is done. Preferred are acrylic resins such as polycarbonate (PC) resin and polymethyl methacrylate (PMMA), and glass epoxy multilayer materials. Particularly preferred are acrylic resins such as polycarbonate (PC) resin and polymethyl methacrylate (PMMA).

  As resin (B) used for a back surface protective layer, the same kind as resin (A) may be different, but it is preferable to use the same resin. As a combination of the resin (A) and the resin (B), when the resin (A) is a PC resin and the resin (B) is a PC resin, the resin (A) is an acrylic resin and the resin (B) is an acrylic resin. In the case of a resin, it is preferable that the resin (A) is a PC resin and the resin (B) is an acrylic resin, and the resin (A) is an acrylic resin and the resin (B) is a PC resin. A particularly preferable combination is a case where the resin (A) is a PC resin and the resin (B) is a PC resin, and the effect of the configuration of the present invention becomes remarkable.

  Although the thickness of a back surface protective layer is not specifically limited, 3.0 mm or more is preferable, More preferably, it is 3.5 mm or more, More preferably, it is 4 mm or more, Most preferably, it is 5 mm or more. The larger this value, the higher the sound insulation and the higher the impact resistance. On the other hand, the upper limit is not particularly limited, but is preferably less than 8 mm, more preferably less than 7 mm. If the back surface protective layer becomes too thick, flexibility is reduced and the weight of the module is increased, so that the merit of using the solar cell module substrate as a resin is lost.

  Further, the relationship between the thickness of the back surface protective layer and the thickness of the surface protective layer is not particularly limited, but the ratio between the thickness of the surface protective layer and the thickness of the back surface protective layer is 1. for the purpose of suppressing warpage after molding. It is preferably 4 times or less, more preferably 1.2 times or less, and still more preferably 1.1 times or less.

Further, the linear expansion coefficient of the resin (B) at -30 to 30 ° C is not particularly limited, but is preferably 30 ppm / K or more, more preferably 45 ppm / K or more, and further preferably 50 ppm / K or more. It is. On the other hand, the upper limit is not particularly limited, but is usually 200 ppm / K or less, preferably 100 ppm / K or less. Further, the Young's modulus at 23 ° C. is preferably 5 GPa or less, more preferably 4 GPa or less, and further preferably 3 GPa or less. On the other hand, the lower limit is not particularly limited, but is usually larger than 0 GPa and preferably 1 GPa or more.
Moreover, resin (B) is the same as that of resin (A) also about the preferable range of a glass transition temperature (Tg) and a weight average molecular weight.

<Encapsulant layer>
The photoelectric conversion layer in the solar cell module of the present invention is usually provided with a sealing material layer so as to cover the photoelectric conversion layer for the purpose of sealing the photoelectric conversion layer and the like. Since a sealing material layer is arrange | positioned so that a photoelectric converting layer may be covered, it is arrange | positioned between a surface protective layer and a photoelectric converting layer, and between a back surface protective layer and a photoelectric converting layer. You may arrange | position a sealing material layer also between a photoelectric converting layer and the below-mentioned reinforcement layer.

The material of these sealing material layers is not particularly limited as long as it is a synthetic resin material that transmits sunlight, and a known and commonly used material can be used. For example, ethylene-vinyl acetate copolymer (EVA) resin, polyvinyl butyral (PVB) resin, modified polyethylene resin modified with maleic acid or silane, modified polypropylene resin, epoxy adhesive, urethane adhesive, etc. are used. be able to.

The thickness of the sealing material layer is preferably 100 μm or more, more preferably 200 μm or more, and further preferably 300 μm or more. On the other hand, it is preferably 2000 μm or less, more preferably 2000 μm or less, and even more preferably 1500 μm or less. When the upper limit is exceeded, the impact resistance is remarkably lowered, and the cell may be damaged by an external impact. On the other hand, when the lower limit value is exceeded, the load on the solar cell part due to vibration increases with an increase in weight, which may cause cell damage as described above.

<Reinforcing layer>
The reinforcing layer of the solar cell module of the present invention is a layer disposed between the surface protective layer and the photoelectric conversion layer and between the back surface protective layer and the photoelectric conversion layer, and the surface generated during cooling after thermal lamination. This is a layer that prevents the photovoltaic cells in the photoelectric conversion layer from being damaged or cracked due to thermal shrinkage stress from the protective layer and the back surface protective layer and thermal shrinkage stress in the use environment where the temperature change is large. is there.

  Moreover, it is preferable that a linear expansion coefficient in -30-30 degreeC is 50 ppm / K or less, More preferably, it is 40 ppm / K or less, More preferably, it is 30 ppm / K or less. As this value decreases, the solar cell damage due to heat shrinkage stress from the surface protective layer tends to decrease. When the linear expansion coefficient exceeds 50 ppm / K, thermal deformation of the reinforcing layer itself tends to increase and the reinforcing effect tends to decrease. On the other hand, the lower limit is not particularly limited, but is preferably 1 ppm / K or more. If the value is too small, it may be smaller than the linear expansion coefficient on the side on which the solar cell module is fixed (inorganic roofing material, metal frame, etc.), which may have an adverse effect.

  Further, the reinforcing layer preferably has a Young's modulus at 23 ° C. of 2 GPa or more. More preferably, it is 3 GPa or more, More preferably, it is 4 GPa or more. As this value increases, the reinforcing effect tends to increase. If the Young's modulus is less than 2 GPa, the reinforcing effect tends to decrease. On the other hand, the upper limit is not particularly limited, but is preferably 300 GPa or less.

  The material of the reinforcing layer is not particularly limited as long as it satisfies the above conditions and has translucency / insulation, but preferably metal (aluminum, iron, stainless steel, copper, brass, galvalume steel plate, etc.) ), Metal oxides of these metals, inorganic oxides (silicon oxide, alumina, zinc oxide, zirconia, forsterite, steatite, cordierite, sialon, zircon, ferrite, mullite, etc.), thin glass, high strength plastic ( Stretched polyethylene terephthalate (stretched PET), stretched polyethylene naphthalate (stretched PEN), polyimide, polyphenylene sulfide, phenol resin, or a glass or carbon fiber reinforced product thereof. More preferably, it is a metal or thin glass. Moreover, when arrange | positioning a reinforcement layer in the light-receiving surface side rather than a photoelectric converting layer, it is necessary to use a material with high light transmittance. As such a material, thin glass, stretched PET, stretched PEN and the like are preferable.

  The thickness of the reinforcing layer is not particularly limited, but is usually 50 μm or more, preferably 75 μm or more, and more preferably 100 μm or more. On the other hand, the upper limit is usually 2000 μm or less, preferably 1500 μm or less.

<Method for manufacturing solar cell module>
Although the manufacturing method of the solar cell module of this invention can use a well-known method, for example, a surface protective layer, a reinforcement layer, a sealing material layer, a photoelectric converting layer, a sealing material layer, a reinforcement layer, a back surface protective layer etc. are included. A solar cell module can be obtained by disposing the multilayer sheet in a vacuum lamination apparatus, heating it after evacuation, and cooling it after a certain period of time.

The heat laminating conditions are not particularly limited, and heat laminating is possible under normal conditions.
It is preferably performed under vacuum conditions, and the degree of vacuum is usually 30 Pa or more, preferably 50 Pa or more, more preferably 80 Pa or more. On the other hand, the upper limit is usually 150 Pa or less, preferably 120 Pa or less, more preferably 100 Pa or less. By setting it as the said range, since generation | occurrence | production of a bubble can be suppressed in each layer in a module, and productivity improves, it is preferable.

  The vacuum time is usually 1 minute or longer, preferably 5 minutes or longer, more preferably 10 minutes or longer. On the other hand, the upper limit is usually 60 minutes or less, preferably 40 minutes or less, more preferably 30 minutes or less. Setting the vacuum time in the above range is preferable because the appearance of the solar cell module after heat lamination becomes good and the generation of bubbles in each layer in the module can be suppressed.

  The pressurizing condition of the thermal laminate is usually a pressure of 50 kPa or more, preferably 70 kPa or more, more preferably 90 kPa or more. On the other hand, the upper limit is preferably 3010 kPa or less. By setting it as the pressurization conditions of the said range, since moderate adhesiveness can be acquired, without damaging a solar cell module, it is preferable also from a durable viewpoint.

  The holding time of the pressure is usually 1 minute or longer, preferably 3 minutes or longer, more preferably 5 minutes or longer. On the other hand, the upper limit is usually 90 minutes or less, preferably 60 minutes or less, more preferably 40 minutes or less. Since the gelation rate of the sealing layer can be made appropriate by setting the holding time, the function of protecting the power generation element of the sealing layer can be sufficiently exhibited, and sufficient adhesive strength can be obtained. be able to.

  The temperature condition of the heat laminate is usually 80 ° C. or higher, preferably 100 ° C. or higher, more preferably 120 ° C. or higher. On the other hand, the upper limit is usually 180 ° C. or lower, preferably 160 ° C. or lower, more preferably 150 ° C. or lower. By setting the temperature range, sufficient adhesive strength can be obtained. Moreover, the heating time of the said temperature is 10 minutes or more normally, Preferably it is 12 minutes or more, More preferably, it is 15 minutes or more. On the other hand, the upper limit is usually 60 minutes or less, preferably 45 minutes or less, more preferably 30 minutes or less. By setting it as the said heating time, since durability of a sealing material is bridge | crosslinked moderately and it can have moderate softness | flexibility, it is preferable.

EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated concretely, it cannot be overemphasized that this invention is not limited only to such a specific aspect.
The following methods were used for evaluation in the examples of the present invention.

[Temperature cycle test]
Using an environmental tester (manufactured by ESPEC Co., Ltd., model: TBE), exposure is performed for 2 hours in an atmosphere at −20 ° C. and for 2 hours in an atmosphere at 80 ° C., and 50 cycles are tested.

[Appearance evaluation]
The appearance after the temperature cycle test was visually observed to confirm the disconnection of the interconnector and the bus bar.

<Example 1>
The solar cell module shown in FIG. 1 was created.
First, as a reinforcing layer, two glass sheets (1) (made by Nippon Sheet Glass Co., Ltd.) having a size ((length) 940 m × (width) 850 m) and a thickness of 1.1 mm were prepared. On the glass sheet (1), an ethylene-vinyl acetate copolymer (hereinafter sometimes abbreviated as “EVA”) sheet having a thickness of 500 μm and the same size as each glass sheet is laminated to obtain a thickness. 300 μm, size ((length) 840 mm × (width) 207 mm) solar battery cell (a solar battery cell in which an amorphous silicon-based power generation layer is laminated on a polyimide (hereinafter referred to as PI) film. No. 3565046 can be manufactured by the method described in Example 1), and three pieces were arranged at equal intervals on the glass sheet (1). Furthermore, the electric wire (interconnector) was wired on the current collecting electrode of the solar battery cell as shown in FIG. Then, another EVA sheet having the same size, size and thickness as described above was placed and another glass sheet (1) was laminated.

  Next, as a reinforcing layer, two glass sheets (2) (made by Nippon Sheet Glass Co., Ltd.) having a size ((length) 940 m × (width) 970 m) and a thickness of 1.1 mm are prepared, one of which On the glass sheet (2), an ethylene-vinyl acetate copolymer (hereinafter sometimes abbreviated as “EVA”) sheet having a thickness of 500 μm and the same size as each glass sheet is laminated to obtain a thickness. 300 μm, size ((length) 840 mm × (width) 207 mm) solar battery cell (a solar battery cell in which an amorphous silicon-based power generation layer is laminated on a polyimide (hereinafter referred to as PI) film. No. 3565046 can be manufactured by the method described in Example 1), and four sheets were arranged at equal intervals on the glass sheet (2). Furthermore, the electric wire was wired on the current collecting electrode of the solar battery cell as shown in FIG. Then, on the glass sheet, an EVA sheet having the same size and thickness as described above was placed, and another glass sheet (2) was laminated.

Using these two laminates, vacuum laminator (NPC, LM-50 × 50-S), 135 ℃
Then, a solar cell submodule was manufactured by hot pressing (vacuum degree 80 Pa, vacuum time 5 minutes, pressurization time 5 minutes, holding 30 minutes).

And these two solar cell submodules are back surface protective layers, a size (length: 2 m, width 1 m), 5 mm thick polycarbonate (hereinafter referred to as PC) sheet (manufactured by Mitsubishi Plastics, Stella). In addition, the rear surface protective layer and the EVA film having a size of 500 μm in thickness were arranged side by side. On top of that, an EVA film having the same size and thickness and a PC sheet having the same size and the same thickness as the back surface protective layer were laminated in this order as the surface protective layer. This laminate is heat-pressed at 110 ° C. using a vacuum laminator (Laminator LM-50 × 50-S, manufactured by NPC) (vacuum degree 80 Pa, vacuum time 5 minutes, pressurization time 5 minutes, holding 45 minutes) Thus, a solar cell module was produced. A temperature cycle test was conducted, but there was no disconnection of the interconnector or bus bar.

<Comparative Example 1>
In Example 1, solar cells are arranged on the glass sheet (1) and the glass sheet (2), and the solar cells are connected to each other using interconnectors as shown in FIG. Produced a solar cell module in the same manner as in Example 1. It was confirmed that the interconnector between the solar cell submodules was disconnected after 50 temperature cycles.

1 Surface protective layer
2 Back side protective layer
3 Photoelectric conversion layer
31 Electric wire (interconnector)
4-10 Sealing material layers 11-14 Reinforcing layer

Claims (7)

  A photoelectric conversion layer including two or more photovoltaic cells connected by a reinforcing layer and an electric wire is laminated between the surface protective layer and the rear surface protective layer, and the electric wire is laminated on the laminated surface (in the laminating direction) of the reinforcing layer. A solar cell module wired inside the peripheral edge of the vertical surface. The solar cell module of Claim 1 laminated | stacked in order of a surface protective layer, a photoelectric converting layer, a reinforcement layer, and a back surface protective layer from the sunlight light-receiving surface side.   The solar cell module according to claim 2, further comprising a reinforcing layer between the photoelectric conversion layer and the surface protective layer.   The solar cell module according to claim 1, wherein the reinforcing layer has a Young's modulus at 23 ° C. of 2 GPa or more and 300 GPa or less.   The solar cell module according to any one of claims 1 to 4, wherein a material of the reinforcing layer is metal or glass.   The solar cell module according to any one of claims 1 to 5, wherein the surface protective layer and the back surface protective layer have a linear expansion coefficient of -30 ° C to 30 ° C of 30 ppm or more. The solar cell module according to claim 1, wherein a thickness of the reinforcing layer is 15 μm or more and 2000 μm or less.