Solar cell module

[0001] The present invention relates to an improved solar cell module, specifically, a transparent organic polymer resin in which at least the surface of the photovoltaic element on the light incident side contains a fibrous inorganic compound. With respect to the solar cell module covered by.

[0002] [Conventional Technology] In recent years, increasing awareness of environmental problems has spread worldwide. Above all, CO₂There is a serious concern about global warming caused by emissions, and the desire for clean energy is increasing. Under these circumstances, solar cells are expected as a clean energy source because of their safety and ease of handling. By the way, there are various forms of solar cells. Typical examples include crystalline silicon solar cells, polycrystalline silicon solar cells, amorphous silicon solar cells, copper indium selenide solar cells, and compound semiconductor solar cells. Among these, thin-film crystalline silicon solar cells, compound semiconductor solar cells, and amorphous silicon solar cells can be increased in area at a relatively low cost, and therefore research and development are being actively promoted in various fields.

[0003] Among these solar cells, thin-film solar cells typified by amorphous silicon solar cells in which silicon is deposited on a conductor metal substrate and a transparent conductive layer is formed on the silicon are lightweight, impact-resistant, and flexible. Since it is rich in sex, it is expected to be a promising future module form. However, unlike the case where silicon is deposited on a glass substrate, it is necessary to cover the surface on the light incident side with a transparent coating material to protect the solar cell, so the following items are required for the surface coating material. .. That is, it has good transparency in the light region of visible light used for solar cell power generation (transparency), and protects the internal photovoltaic element from stress such as scratches and impacts from the outside (resistance). Scratch property), in an outdoor installation environment, it is required that the photovoltaic element is protected, and at the same time, the covering material itself is less deteriorated (weather resistance), and the covering material itself is hard to burn (flame retardant).

[0004] Conventionally, as a surface coating layer satisfying such conditions, a fluororesin film such as glass, an acrylic resin film, a tetrafluoroethylene-ethylene copolymer film, or a polyvinyl fluoride film or fluorine has been conventionally used as the outermost surface coating material. A transparent fluoropolymer thin film using a resin paint or the like is used, and various transparent organic polymer resins such as an ethylene-vinyl acetate copolymer are used as a filler inside the thin film. As the filler, EVA, which is known as a transparent organic polymer resin having excellent heat resistance and weather resistance, is used because it is inexpensive and can be used in a large amount to protect the internal photovoltaic element. Often. However, when glass is used as the outermost surface coating material, the glass is heavy, inflexible, and costly. Therefore, especially in the case of an amorphous silicon solar cell, its characteristics are light weight, flexibility, and so on. It loses the advantage of low cost. Therefore, in the case of an amorphous silicon solar cell, a transparent fluoride polymer thin film is often used as the outermost surface coating material. The fluoride polymer thin film is rich in weather resistance and water repellency, and reduces the decrease in conversion efficiency of the solar cell module due to the decrease in light transmittance due to yellowing / white turbidity due to deterioration of the resin or surface stains. It is possible to make a solar cell module with more flexibility.

[0005] However, when a resin film such as a fluoride polymer thin film is used as the outermost surface coating material, the scratch resistance is lowered as compared with the solar cell module using glass, so that the organic polymer material used as the filler In many cases, it is impregnated with a fibrous inorganic compound such as a glass fiber non-woven fabric and used as a surface coating material. As described above, as a conventional example of using a fibrous inorganic compound as a surface coating material for a solar cell module, for example, USDepartment of Energy, Annual Report Investigation of Test Methods, Material Properties, and Processes for Solar Cell Encapsulants ( June 1979), page 10-1 (hereinafter referred to as Reference 1) and "Final Report on the Investigation of Proposed Process Sequence for the Array Automated Assembly" It is disclosed in task (Aug.1980), page233 (hereinafter referred to as Reference 2). However, the purpose in this case is different from the improvement of scratch resistance, and the distance between the solar cell and the glass as a surface coating material is different. In addition to this, in Japanese Patent Application Laid-Open No. 60-1875 (hereinafter referred to as Reference 3), it is necessary to secure the insulation resistance between the solar cell and the outside, and to secure the exhaust flow path in the evacuation process. In order to solve the problem that cells move and adjacent cells come into contact with each other or strings move and protrude from the outermost glass in the solar cell bonding manufacturing process, the filler is impregnated with glass fiber. Further, Japanese Patent Publication No. 62-33756 (hereinafter referred to as Reference 4) discloses a solar cell device in which a solar cell element is embedded in a glass fiber reinforced plastic. FIG. 6 is a conventional example showing the coating configuration of such a solar cell module. In FIG. 6, 603 is a fluoride polymer thin film layer, 602 is a transparent organic polymer resin, and 601 is a photovoltaic element. Specifically, the fluoride polymer thin film layer 603 is a fluororesin film such as ETFE (ethylene-tetrafluoroethylene copolymer) film and PVF (polyfluorovinyl) film, and the transparent organic polymer resin 602 is EVA (ethylene). -Vinyl acetate copolymer), butyral resin, etc.

[0006] As described above, in the case of a so-called thin-film solar cell such as an amorphous silicon solar cell, in order to take advantage of its features such as light weight, flexibility, and low cost, the outermost surface coating material is used. It is desirable to use a resin film. However, compared to the solar cell module using glass, the solar cell module provided with the resin film layer on the outermost surface is vulnerable to stress such as scratches and impacts from the outside, so the photovoltaic element is vulnerable to these external impacts. In order to protect (internal protection), a transparent organic polymer resin used as a filler is often impregnated with a fibrous inorganic compound such as a glass fiber non-woven fabric to enhance the reinforcing effect and used as a surface coating material. Therefore, the amount of the transparent organic polymer resin needs to be sufficient to impregnate the glass fiber non-woven fabric. However, when the amount of the transparent organic polymer resin is large, there are the following problems. That is, it promotes a decrease in the light transmittance of the surface coating material, which causes a decrease in the conversion efficiency of the solar cell module. Further, since the organic polymer resin mainly used as the filler has high combustion energy and is easily burned, thickening the filler reduces the flame retardancy. In particular, when a solar cell module is installed on a roof or used as a roofing material as a roof-integrated solar cell module, it must be designated as a "non-combustible material" by the Minister of Construction in Japan, and within the United States of America. Now, you must pass Class A in the flammability test specified by UL1703.

[0007] As described above, it is desired to impregnate the glass fiber non-woven fabric with as little transparent organic polymer resin as possible to ensure scratch resistance, flame retardancy, initial filling property and high conversion efficiency. However, the solar cell module impregnated with the glass fiber non-woven fabric has a problem that the surface coating material is colored during long-term outdoor use at a high temperature, resulting in a decrease in conversion efficiency. This is because the synthetic resin used as a binder for the glass fiber non-woven fabric is colored. Further, in the coating material in which these are secured, the glass fiber is raised during long-term outdoor use and the surface coating material becomes opaque, so that the light transmittance to the photovoltaic element is lowered and the conversion efficiency is lowered. There is also. Such embossing of the glass fiber occurs particularly remarkably in a place having a large unevenness such as a mounting member on a photovoltaic substrate. The reason for this is that by reducing the transparent organic polymer resin layer, the cross-linking agent contained in the resin is likely to volatilize to the outside, and the cross-linking rate is lowered, so that the deterioration of the transparent organic polymer resin is easily promoted. Can be considered. Since the transparent organic polymer resin as an adhesive and the resin film, and the transparent organic polymer resin as a filler and the photomotive power element are not in contact with each other, the protruding part of the glass fiber non-woven fabric is adhered at the interface between them. The force decreases. In other words, it is easily affected by humidity from the outside, and moisture from the outside infiltrates through the interface, which not only deteriorates the characteristics of the solar cell, but also causes a leak current through such infiltrated moisture, so the life is 20 years. There is a problem with the reliability of long-term use of the solar cell module, which is said to be. Furthermore, when using a solar cell module as a roofing material, it must have reliability as a roof for a very long period of 50 years, which becomes an even bigger problem. As described above, Documents 1 and 2 describe Craneglass 230 (Crane and) as a glass fiber non-woven fabric. Company) is disclosed to be used. However, since Craneglass230 uses a vinyl acetate resin as a binder and its content is 10% or more, coloring under high temperature conditions is remarkable. That is, the conversion efficiency of the solar cell module is lowered.

[0008] Further, in Document 3 described above, a transparent cover glass is used as the outermost layer, and a glass fiber group in which two long glass fiber mats are stacked is arranged directly above or directly below the photovoltaic element, and ethylene-acetate is used. A solar cell module in which a photovoltaic element is filled with a vinyl copolymer (EVA) is disclosed. However, in this case, glass is used as the outermost surface coating material, and the advantage cannot be utilized in the amorphous silicon solar cell module. Further, Document 4 described above discloses a solar cell module in which two glass fibers having few end portions are arranged on both the upper and lower surfaces of a photovoltaic element, resin is poured into the glass fiber, and the outermost layer is covered with a surface protective film. There is. However, in this case, there is only one glass fiber on the photovoltaic element, and in order to improve scratch resistance, the amount of organic polymer resin as a filler is increased or one non-woven fabric is thickened. Must be done. An increase in the amount of organic polymer resin makes it difficult to ensure flame retardancy, and the use of a thick non-woven fabric causes the glass fibers to emerge during long-term outdoor exposure. Further, the document 4 does not describe ensuring long-term reliability, and there is a point that a solution is required for the embossment of glass fibers after long-term outdoor use.

[0009] An object of the present invention is to solve the above-mentioned problems in a conventional solar cell module, and to provide an improved solar cell module having high reliability even in long-term outdoor use. To provide. Another object of the present invention is to secure scratch resistance, flame retardancy, initial filling property, to secure it for about 20 years without deteriorating the characteristics as a solar cell, and to secure a roof for a long period of about 50 years. High reliability that can secure the adhesive force between the outermost surface resin film and the transparent organic polymer resin without coloring the surface coating material and embossing the glass fiber in long-term outdoor exposure so that high reliability as a material can be obtained. The purpose is to provide solar cell modules.

[Means for Solving the Problems] The present inventors have conducted extensive research and development in order to solve the above problems. As a result, it was found that the above objectives can be achieved by doing the following. That is,<u style="single">In a solar cell module in which at least the surface of the photomotive power element on the light incident side is coated with a coating material made of a transparent organic polymer resin having a fibrous inorganic compound, which is provided with a transparent resin film layer on the outermost surface, the fibers. The fibrous inorganic compound is a glass fiber non-woven fabric in which the fibrous inorganic compound is bonded with an acrylic resin, and the fibrous inorganic compound exists as two or more continuous layers directly above and / or directly below the organic polymer resin, and the fibrous inorganic compound is present. The content of the acrylic resin in the coating material is 2.0% to 6.0%, the thickness of the fibrous inorganic compound is 50 μm to 200 μm, and the thickness of the transparent organic polymer resin is 200 μm to 800 μm. The organic polymer resin has a weight ratio of 4 to 12 with respect to the fibrous inorganic compound, and the transparent resin film layer is unstretched.</u>[Action] The solar cell module based on the above-described configuration includes the following aspects and exerts a remarkable effect. (1) It is a coating material with excellent heat resistance and weather resistance that causes less discoloration at high temperatures and long-term outdoor use. That is, by using an acrylic resin that is less discolored by light and heat as a binder, it is possible to obtain a solar cell module with less decrease in conversion efficiency even during long-term use at high temperature or outdoors. (2) By the presence of the fibrous inorganic compound directly above and / or directly below the organic polymer resin, the fibrous inorganic compound is not embossed, and the outermost surface resin film, the transparent organic polymer resin layer, and the transparent organic polymer resin layer, and Since the adhesive force between the transparent organic polymer resin layer and the photovoltaic element can be secured, it is possible to obtain a highly reliable solar cell module in which the light transmittance of the coating material does not decrease over a long period of use. In addition, high scratch resistance can be ensured. Specifically, for example, as compared with the conventional configuration having one layer of fibrous inorganic compound, the air in the filler can be sufficiently degassed, the initial degassing property is excellent, and sufficient degassing is performed for a long period of time. Even during use, the embossment of the fibrous inorganic compound is suppressed. Further, by using two or more layers of the fibrous inorganic compound, the fibrous inorganic compound is made uniform. (3) By setting the thickness of the fibrous inorganic compound to 50 μm to 200 μm, the effect of (2) above can be further enhanced. That is, the migration of the synthetic resin used as the binder between the fibers is suppressed, and the fibrous inorganic compound becomes stable. (4) Since the weight ratio of the transparent organic polymer resin to the fibrous inorganic compound is 4 to 12, a small amount of the transparent organic polymer resin makes it a coating material having excellent scratch resistance. That is, by reinforcing the transparent organic polymer resin with the fibrous inorganic compound, the thickness of the transparent organic polymer resin can be reduced while ensuring scratch resistance.

(5) The content of the acrylic resin in the fibrous inorganic compound<u style="single">2.0</u>By setting the content to% to 6.0%, the effects of the above (1) and (2) can be further enhanced, and in addition, the fluff of the fibrous inorganic compound is suppressed and the handling becomes easier. That is, the depolymerization of the synthetic resin with respect to the fibrous inorganic compound can be suppressed to the minimum. (6) By setting the wetting index of the outermost transparent resin film layer on the photovoltaic element side to 40 dyne to 45 dyne, it becomes a coating material with excellent adhesive strength and high long-term reliability. That is, by optimizing the resin film and the transparent organic polymer resin, not only the adhesive strength between the resin film and the transparent organic polymer resin at the initial stage is improved, but also the adhesive strength after long-term outdoor exposure is highly reliable. It becomes a material. (7) Since the resin film is a fluoride polymer, the coating has excellent weather resistance. That is, the weather resistance of the fluoride polymer is preferably exhibited in combination with the transparent organic polymer resin of the filler. (8) By converting the fluoride polymer into a tetrafluoroethylene-ethylene copolymer, a coating material utilizing the weather resistance, transparency, and mechanical strength of the tetrafluoroethylene-ethylene copolymer can be obtained. Become.

(9) By setting the tensile elongation at break of the transparent resin film in the ASTM D-882 test method to 200% to 800% in both the vertical and horizontal directions, the outermost surface coating material without cracks can be obtained from the outside. It is possible to prevent the ingress of water and ensure electrical insulation from the outside. (10) By using ethylene-vinyl acetate copolymer (EVA) as the transparent organic polymer resin, the above-mentioned effects can be obtained without significantly changing the composition of the coating material of the conventional solar cell module. it can. (<u style="single">11</u>) Since the thickness of the transparent organic polymer resin is 200 μm to 800 μm, it becomes a coating material having excellent flame retardancy. That is, flame retardancy can be ensured by reducing the amount of the organic polymer resin having high combustion energy.

[Examples of Embodiments] The present invention will be described with reference to the following examples of embodiments. FIG. 1 is a schematic configuration diagram of an example of the solar cell module of the present invention. In FIG. 1, 101 is a photovoltaic element, 102 is a fibrous inorganic compound, 103 is a transparent organic polymer resin as a surface filler, 104 is a transparent resin film located on the outermost surface, and 105 is a filler on the back surface. Reference numeral 106 is a back surface insulating film. Light from the outside enters from the outermost film 104, reaches the photovoltaic element 101, and the generated electromotive force is taken out from the output terminal (not shown). The photovoltaic element 101 in the solar cell module of the present invention is typically a conductive substrate on which a semiconductor photoactive layer and a transparent conductive layer as light conversion members are formed. A schematic configuration diagram as an example is shown in FIG. In FIG. 2, 201 is a conductive substrate, 202 is a back surface reflective layer, 203 is a semiconductor photoactive layer, 204 is a transparent conductive layer, 205 is a current collecting electrode, and 206 is an output terminal.

[0015] The conductive substrate 201 serves as a substrate for the photovoltaic element and at the same time serves as a lower electrode. Materials include silicon, tantalum, molybdenum, tungsten, stainless steel, aluminum, copper, titanium, carbon sheets, galvanized steel sheets, resin films and ceramics on which a conductive layer is formed. A metal layer, a metal oxide layer, or a metal layer and a metal oxide layer may be formed on the conductive substrate 201 as the back surface reflective layer 202. For the metal layer, for example, Ti, Cr, Mo, W, Al, Ag, Ni and the like are used. Further, in the metal oxide layer, for example, ZnO, TiO₂, SnO₂Etc. are used. These metal layers and metal oxide layers can be formed by a resistance heating vapor deposition method, an electron beam vapor deposition method, a sputtering method, or the like. The semiconductor photoactive layer 203 is a portion that undergoes photoelectric conversion, and specific materials include pn junction polycrystalline silicon, pin junction amorphous silicon, and CuInSe.₂, CuInS₂, GaAs, CdS / Cu₂S, CdS / CdTe, CdS / InP, CdTe / Cu₂Examples include compound semiconductors such as Te. The semiconductor photoactive layer can be formed by a known method. That is, in the case of polycrystalline silicon, sheeting of molten silicon or heat treatment of amorphous silicon, in the case of amorphous silicon, plasma CVD using silane gas as a raw material, in the case of compound semiconductors, ion plating, ion beam deposition, vacuum. It can be formed by a vapor deposition method, a sputtering method, an electrodeposition method, or the like.

[0016] The transparent conductive layer 204 serves as an upper electrode of the solar cell. The material used is, for example, In₂O₃, SnO₂, In₂O₃-SnO₂(ITO), ZnO, TiO₂, Cd₂SnO₄There are crystalline semiconductor layers doped with high-concentration impurities. Examples of the forming method include resistance heating vapor deposition, sputtering method, spray method, CVD method, and impurity diffusion method. A grid-shaped current collecting electrode 205 (grid) may be provided on the transparent conductive layer in order to efficiently collect current. Specific examples of the material of the current collecting electrode 205 include a conductive paste such as Ti, Cr, Mo, W, Al, Ag, Ni, Cu, Sn, or a silver paste. As a method for forming the current collecting electrode 205, sputtering using a mask pattern, resistance heating, CVD method, a method of removing unnecessary parts by etching after depositing a metal film on the entire surface, and patterning, and a direct grid by optical CVD. There are a method of forming an electrode pattern, a method of forming a mask of a negative pattern of a grid electrode pattern and then plating, a method of printing a conductive paste, and the like. As the conductive paste, a fine powder of silver, gold, copper, nickel, carbon or the like dispersed in a binder polymer is usually used. Examples of the binder polymer include resins such as polyester, epoxy, acrylic, alkyd, polyvinyl acetate, rubber, urethane, and phenol.

[0017] The output terminal 206 is attached to the conductive substrate and the current collecting electrode in order to take out the electromotive force. A method of joining a metal body such as a copper tab to the conductive substrate by spot welding or solder 207 is adopted, and a method of electrically connecting the metal body to the current collecting electrode by a conductive paste or solder 207 is adopted. When attached to the current collecting electrode 205, it is desirable to provide an insulator 208 in order to prevent the output terminal from coming into contact with the conductive metal substrate or the semiconductor layer and causing a short circuit. The photovoltaic elements formed as described above are connected in series or in parallel depending on the desired voltage or current. In the case of series, the positive side and the negative side of the output terminals are connected, and in the case of parallel, the same polarities are connected. Alternatively, a photovoltaic element can be integrated on an insulated substrate to obtain a desired voltage or current. The material of the metal member used to connect the output terminal and the element can be selected from copper, silver, solder, nickel, zinc, and tin in consideration of high conductivity, solderability, cost, and the like. desirable.

The outermost surface resin film 104, the surface filler 103, and the fibrous inorganic compound 102 used in the present invention will be described below. The surface filler 103 is necessary to coat the unevenness of the photovoltaic element with a resin, protect the element from harsh external environments such as temperature changes, humidity, and impact, and secure the adhesion between the surface film and the element. However, since flame retardancy is also required at the same time, by containing a fibrous inorganic compound, the amount of the filler is reduced, and the surface is filled so as to be a flame retardant material while ensuring scratch resistance. It is desirable to use it as a material. However, when the content of the fibrous inorganic compound in the transparent organic polymer resin is high, as an adverse effect, peeling occurs between the fibrous inorganic compound and the transparent organic polymer resin during long-term outdoor exposure, and the fibrous inorganic compound emerges. The problem of happening arises. That is, in order to secure flame retardancy and to improve the light transmittance and the conversion efficiency of the solar cell module, the thickness of the filler should be thin, and the mechanical strength and the unevenness of the photovoltaic element should be thin. In order to obtain a highly reliable coating material in which the fibrous inorganic compound does not stand out during long-term outdoor exposure, it must be thick to some extent. Specifically, the thickness of the transparent organic polymer resin in the solar cell module is preferably 200 μm to 800 μm. If the thickness of the transparent organic polymer resin is 200 μm or less, the fibrous inorganic compound for obtaining sufficient scratch resistance cannot be contained, and if it is 800 μm or more, flame retardancy cannot be ensured.

[0019] The thickness of the fibrous inorganic compound 102 is preferably 50 μm to 200 μm, the weight ratio of the organic polymer resin to one layer of the fibrous inorganic compound is 15 to 30, and further, the organic polymer resin to the fibrous inorganic compound in the coating material. More preferably, the weight ratio of is 4 to 12. If the thickness of the fibrous inorganic compound is 50 μm or less, it becomes very difficult to produce the fibrous inorganic compound, and in order to obtain the reinforcing effect of the coating material, a large number of fibrous inorganic compounds must be laminated. Therefore, when manufacturing a solar cell module, the process is complicated. When the thickness of the fibrous inorganic compound is 200 μm or more, the acrylic resin contained as an adhesive migrates into the fibrous inorganic compound, and a stable fibrous inorganic compound cannot be obtained. This is because the acrylic resin is depolymerized during long-term outdoor use in the part where the acrylic resin is enriched due to migration, and since there are voids in that part, it is easily affected by external humidity. Furthermore, moisture from the outside infiltrates through the interface and deteriorates the characteristics of the solar cell. The fibrous inorganic compound to be used is a fibrous inorganic compound having a fiber diameter of 4 μm to 15 μm or a mixture of these fibrous inorganic compounds, and it is desirable that the fiber length is a short fiber of 1 mm to 1000 mm. If the weight ratio of the organic polymer resin to the fibrous inorganic compound in the coating material is 4 or less, the transparent organic polymer resin as the filler cannot sufficiently fill the fibrous inorganic compound, and is 12 or more. If this is the case, the reinforcing effect is small and scratch resistance cannot be ensured.

[0020] When the use of the solar cell module is expected in a harsher environment, it is preferable to improve the adhesion between the filler and the photovoltaic element or the surface film. The adhesion can be improved by adding a silane coupling agent or an organic titanate compound to the filler. The amount of these additions is preferably 0.1 to 3 parts by weight, more preferably 0.25 to 1 part by weight, based on 100 parts by weight of the filler resin. Furthermore, by silane coupling treatment on the surface of the fibrous inorganic compound in order to improve the adhesive force between the fibrous inorganic compound and the filler, the adhesive force between the fibrous inorganic compound and the filler is improved, and the fiber in long-term use. It is also possible to suppress the embossment of the state-inorganic compound. Specific examples of the silane coupling agent include vinyl trichlorosilane; vinyltris (β-methoxyethoxy) silane; vinyltriethoxysilane; vinyltrimethoxysilane; γ-methacryloxypropyltrimethoxysilane; β- (3,4-epyl). Cyclohexyl) ethyltrimethoxysilane; γ-glycidoxypropylmethyldiethoxysilane; N-β (aminoethyl) γ-aminopropyltrimethoxysilane; N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane; γ- Examples thereof include aminopropyltriethoxysilane; N-phenyl-γ-aminopropyltrimethoxysilane; γ-mercaptopropyltrimethoxysilane; γ-chloropropyltrimethoxysilane.

[0021] As the fibrous inorganic compound, a glass fiber non-woven fabric is generally used. Generally, a synthetic resin is used as a binder for binding glass fibers to form a glass fiber non-woven fabric. Specifically, the content of the synthetic resin in the glass fiber non-woven fabric is preferably 2.0% to 6.0%, more preferably 3.0% to 4.5%. Further, it is preferable to use an acrylic resin as the synthetic resin. If the content is 2.0% or less, it is difficult to bind the glass fibers, which makes it difficult to manufacture the glass fiber non-woven fabric, and there is a problem in handling because there are many fluffs of the glass fibers. When it is 6.0% or more, the rate of depolymerization of the synthetic resin increases during long-term use, and the voids generated in that portion also increase. Acrylic resin is less discolored by light and heat, so using it as a binder means suppressing discoloration of the surface of the solar cell module on the light receiving surface side, and is a coating material with excellent heat resistance and weather resistance. It becomes.

[0022] As a resin that satisfies the weather resistance, adhesiveness, packing property, heat resistance, cold resistance, impact resistance, etc. required for the filler, ethylene-vinyl acetate copolymer (EVA) and ethylene-methyl acrylate copolymer are co-weighted. Examples thereof include coalescence (EMA), ethylene-ethyl acrylate copolymer (EEA), polyolefin resins such as butyral resin, urethane resins, and silicone resins. Of these, EVA is particularly preferable because it has well-balanced physical properties for solar cell applications. However, since the thermal deformation temperature is low as it is, it easily deforms or creeps under high temperature use, so it is desirable to crosslink to improve heat resistance. In the case of EVA, it is common to crosslink with an organic peroxide. Cross-linking with an organic peroxide is performed by free radicals generated from the organic peroxide extracting hydrogen and halogen atoms in the resin to form CC bonds. Known methods for activating organic peroxides include thermal decomposition, redox decomposition, and ionic decomposition. Generally, the pyrolysis method is preferred.

[0023] Examples of the organic peroxide include hydroperoxide type, dialkyl (allyl) peroxide type, diacyl peroxide type, peroxyketal type, peroxyester type, peroxycarbonate type and ketone peroxide type. Specific examples of the hydroperoxide system include t-butyl peroxide; 1,1,3,3-tetramethylbutyl peroxide; p-menthan hydroperoxide; cumene hydroperoxide; p-cymen hydroperoxide; diisopropylbenzene peroxide; 2,5. -Dimethylhexane 2,5-dihydroperoxide; Cyclohexane peroxide; 3,3,5-trimethylhexanone peroxide, etc. Specific examples of the dialkyl (allyl) peroxide system include di-t-butyl peroxide; dicumyl peroxide; t-butylcumyl peroxide.

[0024] Specific examples of the diacyl peroxide system include diacetyl peroxide; dipropionyl peroxide; diisobutyryl peroxide; dioctanoyl peroxide; didecanoyl peroxide; dilauroyl peroxide; bis (3,3,5-trimethylhexanoyl). ) Peroxide; benzoyl peroxide; m-toluyl peroxide; p-chlorobenzoyl peroxide; 2,4-dichlorobenzoyl peroxide; peroxy humic acid and the like.

[0025] Specific examples of the peroxyketal system include 2,2-di-t-butylperoxybutane; 1,1-di-t-butylperoxycyclohexane; 1,1-di- (t-butylperoxy) -3. , 3,5-trimethylcyclohexane; 2,5-dimethyl-2,5-di (t-butylperoxy) hexane; 2,5-dimethyl-2,5-di (t-butylperoxy) hexin-3; 1, 3-Di (t-butyl peroxyisopropyl) benzene; 2,5-dimethyl-2,5-dibenzoyl peroxyhexane; 2,5-dimethyl-2,5-di (peroxybenzoyl) hexin-3; n-butyl- 4,4-Bis (t-butylperoxy) ballerate, etc.

[0026] Specific examples of the peroxyester system include t-butylperoxyacetate; t-butylperoxyisobutyrate; t-butylperoxypivalate; t-butylperoxyneodecanoate; t-butylperoxy3,3, 5-trimethylhesanoate; t-butylperoxy 2-ethylhexanoate; (1,1,3,3-tetramethylbutylperoxy) 2-ethylhexanoate; t-butylperoxylaurate; t-butylperoxy Benzoate; di (t-butylperoxy) adipate; 2,5-dimethyl 2,5-di (peroxy2-ethylhexanoyl) hexane; di (t-butylperoxy) isophthalate; t-butylperoxymalate; acetylcyclohexyl Such as sulfonyl peroxide.

[0027] Specific examples of the peroxycarbonate system include t-butylperoxyisopropylcarbonate; di-n-propylperoxydicarbonate; di-sec-butylperoxydicarbonate; di (isopropylperoxy) dicarbonate; di (di (isopropylperoxy) dicarbonate. 2-Ethylhexylperoxy) dicarbonate; di (2-ethoxyethylperoxy) dicarbonate; di (methoxyidpropylperoxy) carbonate; di (3-methoxybutylperoxy) dicarbonate; bis- (4-t-butylcyclohexylperoxy) dicarbonate, etc. is there. Specific examples of the ketone peroxide system include acetylacetone peroxide; methyl ethyl ketone peroxide; methyl isobutyl ketone peroxide; and ketone peroxide. In addition to these, vinyltris (t-butylperoxy) silane can also be used.

[0028] The amount of the organic peroxide added is 0.5 to 5 parts by weight with respect to 100 parts by weight of the filler resin. It is possible to use the organic peroxide in combination with the filler and perform cross-linking and thermocompression bonding while pressurizing and heating. The heating temperature and time can be determined by the thermal decomposition temperature characteristics of each organic peroxide. Generally, the heating and pressurization is completed at a temperature and time at which the thermal decomposition proceeds by 90% or more preferably 95% or more. The gel fraction of the filler according to this is preferably 80% or more, more preferably 90% or more. When the gel fraction is 80% or less, it means that there are many non-crystalline parts in the resin, that is, the deterioration of the resin is promoted. In order to carry out the cross-linking reaction efficiently, it is desirable to use triallyl isocyanurate (TAIC) called a cross-linking aid. The amount added is generally 1 to 5 parts by weight with respect to 100 parts by weight of the filler resin.

[0029] The material of the filler used in the present invention is excellent in weather resistance, but an ultraviolet absorber may be used in combination for further improving the weather resistance or protecting the lower layer of the filler. .. The amount added is about 0.1 to 0.5 parts by weight with respect to 100 parts by weight of the resin. As the ultraviolet absorber, known compounds of salicylic acid type, benzophenone type, benzotriazole type and cyanoacrylate type can be used. Specific examples of the salicylic acid system include phenylsalicylate; p-tert-butylphenylsalicylate; p-octylphenylsalicylate.

[0030] Specific examples of the benzophenone system include 2,4-dihydroxybenzophenone; 2-hydroxy-4-methoxybenzophenone; 2-hydroxy-4-octoxybenzophenone; 2-hydroxy-4-dodecyloxybenzophenone; 2,2. -Dihydroxy-4-methoxybenzophenone; 2,2-dihydroxy-4,4-dimethoxybenzophenone; 2-hydroxy-4-methoxy-5-sulfobenzophenone; bis (2-methoxy-4-hydroxy-5-benzophenone) ) Methoxy etc.

[0031] Specific examples of the benzotriazole system include 2- (2'-hydroxy-5'-methylphenyl) benzotriazole; 2- (2'-hydroxy-5'-tert-butylphenyl) benzotriazole; 2- (2'-Hydroxy-3', 5'-di-tert-butylphenyl) benzotriazole; 2- (2'-hydroxy-3'-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole; 2 -(2'-Hydroxy-3', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole; 2- (2'-hydroxy-3', 5'-di-tert-amylluphenyl) benzo Triazole; 2-{2'-Hydroxy-3'-(3 ", 4", 5 ", 6"-Tetrahydrophthalimidemethyl) -5'-Methylphenyl} Benzotriazole; 2,2-Methylenebis { 4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazole-2-yl) phenol} and the like. Specific examples of the cyanoacrylate system include 2-ethylhexyl-2-cyano-3,3'-diphenyl acrylate; ethyl-2-cyano-3,3'-diphenyl acrylate. One or more of these UV absorbers can be added.

[0032] A hindered amine-based light stabilizer can be used as a method for imparting weather resistance in addition to the above-mentioned ultraviolet absorber. Hindered amine-based light stabilizers do not absorb UV rays like UV absorbers, but show a remarkable synergistic effect when used in combination with UV absorbers. The amount added is generally about 0.1 to 0.3 parts by weight with respect to 100 parts by weight of the resin. Of course, there are other light stabilizers other than hindered amines that function as light stabilizers, but they are often colored and are not desirable for the filler of the present invention. The hindered amine-based photostabilizer includes dimethyl-1- (2-hydroxyethyl) succinate-4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate; poly [{6- (1,1, 1,3,3-Tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene} {2 , 2,6,6-Tetramethyl-4-piperidyl) imino}]; N, N'-bis (3-aminopropyl) ethylenediamine, 2,4-bis [N-butyl-N- (1,2,2) , 6,6-Pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate; bis (2,2,6,6-tetramethyl-4-piperidyl) severate; 2-( 3,5-Di-tert-4-hydroxybenzyl) -2-n-butylmalate bis (1,2,2,6,6-pentamethyl-4-piperidyl) and the like can be used.

[0033] It is preferable to use a low volatility ultraviolet absorber in consideration of the usage environment of the solar cell module. If a light stabilizer is added at the same time as the ultraviolet absorber, the filler becomes more stable to light. Furthermore, it is also possible to add an antioxidant to improve heat resistance and heat workability. The amount added is preferably 0.1 to 1 part by weight with respect to 100 parts by weight of the resin. As such an antioxidant, monophenol-based, bisphenol-based, polymer-type phenol-based, sulfur-based, and phosphoric acid-based ones can be used. Specific examples of the monophenol system include 2,6-di-tert-butyl-p-cresol; butylated hydroxyanisol; 2,6-di-tert-butyl-4-ethylphenol and the like.

[0034] Specific examples of the bisphenol system include 2,2'-methylene-bis- (4-methyl-6-tert-butylphenol); 2,2'-methylene-bis- (4-ethyl-6-tert-). Butylphenol); 4,4'-thiobis- (3-methyl-6-tert-butylphenol); 4,4'-butylidene-bis- (3-methyl-6-tert-butylphenol); 3,9-bis {1 , 1-Dimethyl-2- {β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl} 2,4,8,10-tetraoxaspiro} 5,5 undecane, etc. ..

[0035] Specific examples of the high molecular weight phenol system include 1,1,3-tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane; 1,3,5-trimethyl-2,4. , 6-Tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene; tetrakis- {methylene-3- (3', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate} Methyl; bis (3,3'-bis-4'-hydroxy-3'-tert-butylphenyl) butyric acid} glucol ester; 1,3,5-tris (3', 5'-di-tert- Butyl-4'-hydroxybenzyl) -s-triazine-2,4,6- (1H, 3H, 5H) trione; triphenol (vitamin E) and the like.

[0036] Specific examples of the sulfur system include dilaurylthiodipropionate; dimyristylthiodipropionate; and distearylthiopropionate. Specific examples of the phosphoric acid system include triphenylphosphite; diphenylisodecylphosphite; phenyldiisodecylphosphite; 4,4'-butylidene-bis- (3-methyl-6-tert-butylphenyl-di-tridecyl) phos. Fight; Cyclic Neopentan Tetraylbis (Octadecylphosphite); Tris (Mono and / or Diphenylphosphite; Diisodecylpentaerythritol diphosfite; 9,10-dihydro-9-oxa-10-phosphaphenaslen-10- Oxide; 10- (3,5-di-tert-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; 10-decyloxy-9,10 -Dihydro-9-oxa-10-phosphaphenanthrene; cyclic neopentanetetraylbis (2,4-di-tert-butylphenyl) phosphite; cyclic neopentanetetraylbis (2,6-di) -tert-Methylphenyl) phosphite; 2,2-methylenebis (4,6-tert-butylphenyl) octylphosphite, etc.

[0037] In order to suppress a decrease in the amount of light reaching the photovoltaic element as much as possible, the surface filler must be transparent, specifically 80 in the visible light wavelength region having a light transmittance of 400 nm or more and 800 nm or less. It is desirable that it is% or more, and more preferably 90% or more. Further, in order to facilitate the incident of light from the atmosphere, the refractive index at 25 ° C is preferably 1.1 to 2.0, and more preferably 1.1 to 1.6. Since the surface resin film 104 used in the present invention is located on the outermost layer of the solar cell module, it has performance for ensuring long-term reliability of the solar cell module in outdoor exposure, including weather resistance, stain resistance, and mechanical strength. is necessary. Examples of the resin film used in the present invention include fluororesin and acrylic resin. These medium fluororesins are particularly preferable because they are excellent in weather resistance and stain resistance. Specific examples of the fluororesin include polyvinylidene fluoride resin, polyvinyl fluoride resin, and tetrafluoroethylene-ethylene copolymer. The polyvinylidene fluoride resin is excellent in terms of weather resistance, but the tetrafluoroethylene-ethylene copolymer is excellent in terms of both weather resistance and mechanical strength and transparency.

[0038] In order to improve the adhesiveness with the filler, it is desirable to perform surface treatment such as corona treatment, plasma treatment, ozone treatment, UV irradiation, electron beam irradiation, and flame treatment on the surface film. Specifically, it is preferable that the wetting index on the photovoltaic element side is 35 dyne. If the wetting index is 35 dyne or less, the adhesive force between the resin film and the filler is not sufficient, and the filler and the resin film are peeled off. Further, the resin film is a film that has not been stretched because the stretched film causes cracks.<u style="single">To use.</u>Specifically, in the ASTM D-882 test method, the tensile elongation at break is preferably 200% to 800% in both the vertical direction and the horizontal direction.

[0039] The insulating film 106 is necessary to maintain electrical insulation between the conductive metal substrate of the photovoltaic element 101 and the outside. As the material, a material having sufficient flexibility with a conductive metal substrate, which can secure sufficient electrical insulation, has excellent long-term durability, and can withstand thermal expansion and contraction is preferable. Suitable examples of the insulating film include nylon, polyethylene terephthalate, polycarbonate and the like. The filler 105 on the back surface is for adhering the photovoltaic element 101 and the insulating film 106 on the back surface. As the material, a material having sufficient flexibility that can secure sufficient adhesiveness to the conductive substrate, has excellent long-term durability, and can withstand thermal expansion and contraction is preferable. Suitable materials include hot melt materials such as EVA and polyvinyl butyral, double-sided tape, and flexible epoxy adhesives. In addition, it is often the same material as the surface filler 103. A reinforcing plate may be attached to the outside of the coating film on the back surface in order to increase the mechanical strength of the solar cell module or to prevent distortion and warpage due to temperature changes. For example, steel plates, plastic plates, and FRP (glass fiber reinforced plastic) plates are preferable.

[0040] In order to obtain the solar cell module by using the photovoltaic element, the filler, the surface resin film, and the back surface coating material described above, for example, the following method can be adopted. In order to cover the light receiving surface of the photovoltaic element, a method of preparing a filler 103 molded into a sheet shape and heat-pressing the filler material on the front and back surfaces of the element is common. The coating configuration of the solar cell module is as shown in FIG. That is, the photovoltaic element 101, the fibrous inorganic compound 102, the filler 103, the front surface resin film 104, the back surface filler 105, and the insulating film 106 are laminated in the order shown in the figure or in the reverse order, and heat-bonded. However, in order to cover the photovoltaic element with a small amount of filler, it is more preferable to stack the resin films in the order shown in the figure on top. Further, by providing two or more continuous fibrous inorganic compounds directly above and below the filler, the degassing property is improved, and the solar cell module has flame retardancy, scratch resistance, heat resistance, and weather resistance. be able to. Specifically, by using two or more layers of fibrous inorganic compounds, higher degassing properties can be ensured as compared with the case of one layer, and the fibrous inorganic compounds can be made into highly uniform fibrous inorganic compounds. Therefore, scratch resistance is also improved. When the reinforcing plate is provided, it may be laminated on the insulating film via an adhesive and crimped, and this may be performed at the same time as the above step or after the step. The heating temperature and heating time at the time of crimping are determined by the temperature and time at which the crosslinking reaction proceeds sufficiently. As a method of heat crimping, various conventionally known double vacuum exhaust methods, single vacuum exhaust methods, roll lamination and the like can be selected and used. Among them, heat crimping by the single vacuum exhaust method is a preferable method because a solar cell module can be easily manufactured by a low-cost device.

[Examples] Hereinafter, the present invention will be described in detail based on Examples. The present invention is not limited to these examples.

[Example 1] [Manufacture of photovoltaic device] An amorphous silicon (a-Si) solar cell (photovoltaic device) having the configuration shown in FIG. 2 was manufactured as follows. An Al layer (thickness 5000 Å) and a ZnO layer (thickness 5000 Å) were sequentially formed as the back surface reflective layer 202 on the washed stainless steel substrate 201 by a sputtering method. Then, by plasma CVD method, SiH₄And PH₃And H₂N-type a-Si layer from the mixed gas of SiH₄And H₂I-type a-Si layer from the mixed gas of SiH₄And BF₃And H₂A p-type microcrystalline μc-Si layer is formed from the mixed gas of the above, and the n layer film thickness is 150 Å / i layer film thickness 4000 Å / p layer film thickness 100 Å / n layer film thickness 100 Å / i layer film thickness 800 Å / p layer film thickness. A tandem type a-Si photoelectric conversion semiconductor layer 203 having a layer structure of 100 Å was formed. Next, as the transparent conductive layer 204, In₂O₃Thin film (thickness 700 Å), O₂It was formed by vapor deposition of In in an atmosphere by a resistance heating method. Further, the grid electrode 205 for current collection was formed by screen printing of silver paste. Then, a copper tab was attached to the stainless steel substrate as the negative terminal 206a using solder 207, and a tin foil tape was attached to the current collecting electrode 205 with solder 207 as the positive terminal 206b. Thus, a plurality of photovoltaic elements were obtained.

[Manufacture of Cell Block] A solar cell cell block having the configuration shown in FIG. 3 was manufactured by connecting the plurality of photovoltaic elements obtained above in series. That is, after arranging the photovoltaic elements, the positive terminal 308 of one element of the adjacent element and the negative terminal 309 of the other element were connected by a copper tab 307 using solder. As a result, a solar cell block in which three elements were serialized was obtained. At this time, the copper tab connected to the output terminal of the endmost element was turned to the back surface so that the output could be taken out from the hole of the back surface coating layer described later.

[0044] [Modularization] EVA sheet 403 (manufactured by Springbone Laboratories, trade name: PHOTOCAP A9918P) is placed on the light receiving surface side of the cell block obtained above.^*/ 200rms / 936, thickness 460μm) and glass fiber non-woven fabric (manufactured by Honshu Paper Co., Ltd., product name: Glasper GMC-00-020 (B), basis weight 20g / m², Thickness 100 μm, binder acrylic resin 4.0 wt.% Containing) 402 and unstretched ETFE film 404 (manufactured by DuPont, trade name: unstretched Tefzel film, thickness 50 micron), insulating film as back coating material 405 (Dupont, trade name: Dartec, thickness 75 μm), EVA sheet 403, which is the same as the one used for the surface coating material as an adhesive, and galvalume steel plate 406 (zinc-plated steel plate, thickness) painted black as a reinforcing plate. ETFE film 404 / glass fiber non-woven fabric 402 / glass fiber non-woven fabric 402 / EVA403 / glass fiber non-woven fabric 402 / glass fiber non-woven fabric 402 / cell block 401 / EVA403 / insulating film 405 / EVA403 / reinforcing plate 406 Stack them in order so that the 404s are on top, and while pressurizing and degassing using a single vacuum exhaust laminating device, put them in an oven that has been pre-conditioned at 150 ° C for 100 minutes, and then put them at 150 ° C for 30 minutes. A solar cell module was obtained by heating. The EVA sheet used here has 1.5 parts by weight of a cross-linking agent, 0.3 parts by weight of an ultraviolet absorber, 0.1 parts by weight of a light stabilizer, and an antioxidant with respect to 100 parts by weight of EVA resin (vinyl acetate content 33%). It contains 0.2 parts by weight and 1.0 part by weight of the silane coupling agent. The output terminal was turned to the back surface of the photovoltaic element in advance, and after laminating, the output could be taken out from the terminal outlet opened in advance in the galvalume steel plate. Thus, the solar cell module was obtained.

[0045] [Example 2] A solar cell module was produced in the same manner as in Example 1 except that two glass fiber non-woven fabrics were laminated only directly under the EVA sheet in Example 1.

[Example 3] A solar cell module was produced in the same manner as in Example 1 except that the thickness of the EVA sheet was changed to 600 μm in Example 1.

[Example 4] A solar cell module was produced in the same manner as in Example 1 except that three glass fiber non-woven fabrics were laminated directly above and directly below in Example 1 and the thickness of the EVA sheet was changed to 600 μm. ..

[Example 5] A solar cell module was produced in the same manner as in Example 1 except that the insulating film on the back surface was changed to a PET film (thickness 50 μm) in Example 1.

【0049】【<u style="single">Reference example</u>] In Example 1, the glass fiber non-woven fabric used is GMC-00-080 (B) (weight: 80 g / m).², Thickness 400 μm), and the same as in Example 1 except that the ETFE film / EVA / glass fiber non-woven fabric / cell block / EVA / insulating film / EVA / reinforcing plate are stacked in order so that the ETFE film is on top. A solar cell module was manufactured.

[Comparative Example 1] A solar cell module was produced in the same manner as in Example 1 except that a glass nonwoven fabric using polyvinyl acetate was used as a binder for the glass fiber nonwoven fabric in Example 1.

[Comparative Example 2] In Example 1, a glass fiber non-woven fabric has a basis weight of 5 g / m.²A solar cell module was produced in the same manner as in Example 1 except that the thickness was 25 μm.

[Comparative Example 3] In Example 1, the glass fiber non-woven fabric was used as GMC-00-080 (B) (weight: 80 g / m).²A solar cell module was produced in the same manner as in Example 1 except that the thickness was 400 μm).

[Comparative Example 4] In Example 1, a solar cell module was produced in the same manner as in Example 1 except that a glass fiber non-woven fabric having a binder content of 15% was used.

[Comparative Example 5] A solar cell module was produced in the same manner as in Example 1 except that the surface resin film was changed to a stretched ETFE film thickness of 38 μm in Example 1.

[Comparative Example 6] A solar cell module was produced in the same manner as in Example 1 except that the thickness of the EVA sheet was changed to 1000 μm in Example 1.

[0056] [Evaluation] Examples 1 to the above<u style="single">5, the above reference example,</u>The following items were evaluated for each of the solar cell modules obtained in Comparative Examples 1 to 6 above. The obtained evaluation results are summarized in Table 1.

(1) Initial appearance The initial appearance of the solar cell module was visually evaluated. The evaluation results are shown in Table 1 according to the following evaluation criteria. That is, : when there is no appearance defect, Δ: when there are some appearance defects but practically acceptable, ×: when there are very large appearance defects such as poor deaeration and module curvature.

(2) Scratch resistance By the method shown in FIG. 5, the most uneven portion of the module surface on the metal member is scratched with a weight of 2 pounds or 5 pounds, and the surface coating material after scratching is external. It was evaluated whether or not the insulation property with and could be maintained. The judgment was rejected when the module was immersed in an electrolyte solution with a conductivity of 3000 Ω · cm and the leakage current when a voltage of 2200 volt was applied between the device and the solution exceeded 50 μA. The evaluation results are shown in Table 1 on the basis of 5 pounds pass: , 2 pounds pass: , and fail.

(3) The flame-retardant solar cell module is installed on a deck tilted horizontally by 22 degrees, and a gas burner flame of 760 ± 28 ° C is applied to the surface covering material side of the solar cell module for 10 minutes. Those whose flame spread did not exceed 6 feet from the tip of the sample were accepted. The evaluation results are shown in Table 1 based on the criteria of : pass and ×: fail.

(4) Appearance observation under high temperature and high humidity After storing the solar cell module at 85 ° C / 85% (relative humidity) for 200 hours, the solar cell module is taken out and the appearance is visually changed. It was. The evaluation results are shown in Table 1 based on the following criteria. That is, : No change in appearance, : Some defects in appearance but practically acceptable, ×: Defects in appearance such as poor degassing, curvature of module, discoloration of surface covering material, etc. If very large.

(5) Weather resistance A solar cell module is put into a sunshine weather meter, an accelerated weather resistance test is performed by light irradiation with a xenon lamp and a rainfall cycle, and changes in appearance are observed after 5000 hours and 10000 hours. did. The results are: : When there is no change in appearance, : When there are some defects in appearance but practically acceptable, ×: When there is significant peeling or discoloration of the coating material and there is clearly practically acceptable Table 1 shows the criteria.

[0062] (6) Put the solar cell module into the light-resistant super-energy irradiation tester (manufactured by Suga Test Instruments Co., Ltd.) and irradiate it with ultraviolet rays for 5 hours using a metal halide lamp [Intensity: 100 mW / cm.²@ 300nm-400nm, Atmosphere: Black panel Temperature 70 ° C / Humidity 70% RH] and 1 hour dew condensation [Temperature 30 ° C / Humidity 96% RH] are repeated in a dew cycle test, and the appearance after 2000 hours The change was observed. The results are: : No change in appearance, : Some defects in appearance but practically acceptable, ×: Significant peeling and discoloration of the coating material, and apparently practically acceptable. It is shown in Table 1 according to the criteria of.

(7) The heat-resistant solar cell module was left in an atmosphere of 90 ° C for 3000 hours, and changes in appearance were observed. The results are shown in Table 1 on the basis that those that do not change are marked with , and those that do change such as discoloration are marked with x.

[0064] As is clear from Table 1, all of the solar cell modules of the examples have practically sufficient scratch resistance, flame retardancy, weather resistance, light resistance, and heat resistance. Both the initial appearance and the defects such as poor filling were good. In addition, even after 10,000 hours of the high temperature and high humidity test and the weather resistance test, there was no peeling or embossing of the glass fiber non-woven fabric, which would be a practical defect, and the module was able to have an excellent appearance. In addition, high reliability can be ensured even for long-term use. On the other hand, in Comparative Example 1 in which a glass woven fabric using polyvinyl acetate was used as the binder, the coating material was significantly discolored after the heat resistance test, which clearly promoted a decrease in the conversion efficiency of the solar cell module. It was. Further, in Comparative Example 2 in which the amount of the glass fiber non-woven fabric was small, sufficient scratch resistance could not be ensured. Further, since the amount of the glass fiber non-woven fabric was small, the thickness of EVA as a filler could not be secured, and ETFE of EVA was slightly peeled off after the weather resistance test and the light resistance test. On the contrary, in Comparative Example 3 in which the amount of the glass fiber non-woven fabric was large, the glass fiber non-woven fabric could not be sufficiently filled, and the initial appearance was large in defects. Of course, with regard to weather resistance, light resistance, heat resistance, etc., the deterioration of the EVA sheet due to the infiltration of moisture is promoted, and sufficient reliability cannot be obtained.

[0065] In Comparative Example 4, since the glass fiber non-woven fabric containing 15% of the binder content of the glass fiber non-woven fabric is used, all of the high temperature and high humidity test, the weather resistance test, the light resistance test, and the heat resistance test. In this test, the surface coating material was colored, which resulted in a decrease in the conversion efficiency of the solar cell module. In Comparative Example 5 in which a stretched film was used as the outermost ETFE film, cracks were confirmed in the ETFE film from the initial appearance, which made it susceptible to moisture infiltration and markedly glass fiber at a weather resistance of 10,000 hours. Embossing of the non-woven fabric occurred. Further, in Comparative Example 6 in which the thickness of the EVA sheet as the surface filler was as thick as 1000 μm, a good initial appearance was obtained, but combustibility could not be ensured due to the large amount of EVA. Furthermore, discoloration after the heat resistance test was also confirmed.

[0066] [Table 1]<img file="JP3710187B2_D0001.tif" />[Effect of the Invention] According to the present invention, at least the light incident side surface of the photovoltaic element is made of a transparent organic polymer resin having a fibrous inorganic compound having a transparent resin film layer on the outermost surface. In a solar cell module coated with a coating material, since the fibrous inorganic compound is a glass fiber non-woven fabric bonded with an acrylic resin, it is possible to achieve both scratch resistance and flame retardancy, which have been problems in the past. It is possible to obtain a highly reliable solar cell module without any change in appearance such as embossment of a glass fiber non-woven fabric in a long-term outdoor exposure excellent in heat resistance, weather resistance, and light resistance.

BRIEF DESCRIPTION OF THE DRAWINGS [Fig. 1] Fig. 1 is a schematic configuration diagram of a solar cell module of the present invention.

FIG. 2 is a schematic cross-sectional view showing a basic configuration of a photovoltaic element used in the solar cell module of FIG.

FIG. 3 is a cross-sectional view of the serialized module in the present invention.

FIG. 4 is a schematic cross-sectional view of the solar cell module according to the present invention.

FIG. 5 is a schematic view showing a scratch resistance test.

FIG. 6 is a schematic cross-sectional view showing an example of a conventional solar cell module.

[Description of Code] 101,301,401,601 Photovoltaic element 103 Surface filler 302,403,602 Filler 102,402 Glass fiber non-woven fabric 104,303,404,603 Surface resin film 105 Back filler 106,304,405,604 Insulation film 406 Reinforcing material 201 Conductive substrate 202 Back reflective layer 203 Semiconductor photoactive layer 204 Transparent Conductive layer 205,305a Current collecting electrode (plus side) 305b Current collecting electrode (minus side) 206a Output terminal (plus side terminal) 206b Output terminal (minus side terminal) 207,308 Solder 208,307 Insulation tape 306 Copper tab 501 Solar cell module surface 502 Blade