JP5041888B2 - Sheet for solar cell encapsulant - Google Patents

Description

  The present invention relates to a solar cell encapsulant sheet for fixing a solar cell element in a solar cell module and a solar cell module in which the solar cell element is sealed with the solar cell encapsulant sheet. More specifically, the present invention relates to a solar cell encapsulant sheet having excellent transparency, flexibility, workability, durability, crosslinkability, and excellent adhesion stability, and a solar cell module using the sheet.

  Against the background of increasing environmental problems in recent years, hydroelectric power generation, wind power generation and solar power generation are attracting attention as clean energy. Among these, solar power generation is here because the power generation efficiency of solar cell modules has been significantly improved, but the price has declined, and the national and local governments have promoted the introduction of residential solar power generation systems. The spread has been remarkable for several years.

  Photovoltaic power generation directly converts solar energy into electrical energy using a semiconductor (solar cell element) such as a silicon cell, but the function of the solar cell element used here is reduced when it directly contacts the outside air. The solar cell element is sandwiched between a sealing material or a protective film to prevent foreign matters from entering and moisture and the like from entering together with buffering.

  As this solar cell encapsulant sheet, it is common to use a cross-linked product of an ethylene / vinyl acetate copolymer having a vinyl acetate content of 25 to 33% by weight in terms of transparency, flexibility, workability and durability. (See, for example, Patent Document 1). However, when the vinyl acetate content is high, the ethylene / vinyl acetate copolymer has high moisture permeability, and the adhesiveness to the upper transparent protective material, the back sheet, and the like may be reduced accordingly. For this reason, we use backsheets with high barrier properties and seal the module periphery with butyl rubber with high barrier properties to make it moisture-proof. However, with the widespread use of solar cells, the durability (adhesiveness) has been increasing year by year. Etc.), and higher level countermeasures are required.

  As a countermeasure against this, it is conceivable to use an ethylene / vinyl acetate copolymer having a low vinyl acetate content. In this case, however, the transparency tends to decrease, resulting in a decrease in the amount of received sunlight, and the solar cell. Output may be reduced, and the flexibility of the sheet may be reduced.

Japanese Examined Patent Publication No. 62-14111

  The object of the present invention is to use an ethylene / vinyl acetate copolymer having a high vinyl acetate content, taking advantage of the excellent transparency, flexibility, processability, durability, crosslinkability, etc. of the ethylene vinyl acetate copolymer. It is in providing the solar cell sealing material sheet | seat and the solar cell module using this sealing material sheet | seat in which the stability of adhesion | attachment was improved significantly.

  That is, the present invention provides an intermediate layer (A) mainly composed of an ethylene / vinyl acetate copolymer having a vinyl acetate content of 15 to 40% by weight and (meth) provided on both surfaces of the intermediate layer (A). A crosslinkable laminate sheet having an outer layer (B) mainly composed of an ethylene / (meth) acrylate copolymer having an acrylate content of 15 to 40% by weight and having a total thickness of 0.2 to 2 mm is used. It is related with the sheet | seat for solar cell sealing materials characterized by the above-mentioned.

  In the solar cell encapsulant sheet, the melt flow rate (JIS K7210-1999, 190 ° C., 2160 g load) of the ethylene / vinyl acetate copolymer and the ethylene / (meth) acrylic acid ester copolymer was 0 respectively. It is preferable that it exists in the range of 1-150g / 10min.

  In the solar cell encapsulant sheet, the intermediate layer (A) mainly composed of an ethylene / vinyl acetate copolymer and the outer layer (B) mainly composed of an ethylene / (meth) acrylate copolymer. It is preferable that an additive selected from a crosslinking agent, a crosslinking aid, a silane coupling agent, an ultraviolet absorber, a light stabilizer and an antioxidant is blended.

  In the solar cell encapsulant sheet, the thickness of the intermediate layer (A) mainly composed of an ethylene / vinyl acetate copolymer and the outer layer mainly composed of an ethylene / (meth) acrylate copolymer. The total thickness ratio [(A) / ((B) + (B))] of (B) is preferably 9/1 to 1/9.

  Further, in the solar cell encapsulant sheet, a layer (A) containing ethylene / vinyl acetate copolymer as a main component and a layer (B) containing ethylene / (meth) acrylate copolymer as a main component. It is preferable that each gel fraction is 70% or more.

  The present invention also relates to a solar cell module using the solar cell encapsulant sheet.

  According to the present invention, transparency, workability, flexibility, weather resistance, cross-linking characteristics, etc. are substantially higher than those of a conventionally used sheet for encapsulating solar cells made of an ethylene / vinyl acetate copolymer. Therefore, it is possible to provide a sealing material sheet having improved adhesiveness and adhesion stability, in particular, adhesion to a back sheet made of resin such as polyester, acrylic resin, and polycarbonate. The performance is stabilized in the battery module.

  In the solar cell encapsulant sheet of the present invention (solar cell encapsulating sheet), the main component is an ethylene / vinyl acetate copolymer having a vinyl acetate content of 15 to 40% by weight, preferably 18 to 35% by weight. And (meth) acryl as a layer in direct contact with a substrate such as a solar cell element, glass (upper protective material), and back sheet (lower protective material) on both sides of the intermediate layer (A). An outer layer (B) mainly composed of an ethylene / (meth) acrylic acid ester copolymer having an acid ester content of 15 to 40% by weight, preferably 18 to 30% by weight, is provided (laminated). It has a three-layer structure of at least [(B) / (A) / (B)], and the total thickness is in the range of 0.2 to 2 mm. The ethylene / vinyl acetate copolymer layer (A) contains an ethylene / (meth) acrylate copolymer in a small amount (for example, up to 50% by weight based on the ethylene / vinyl acetate copolymer). It may be. In the case of a small amount of the ethylene / (meth) acrylate copolymer sealing layer (for example, up to 50% by weight based on the ethylene / (meth) acrylate copolymer), the ethylene / vinyl acetate copolymer It may be contained.

  In the present invention, the (B) layer provided adjacent to the (A) layer on both sides of the (A) layer is ethylene / (meth) acrylic acid having a (meth) acrylic acid ester content of 15 to 40% by weight. As long as it has an ester copolymer as a main component, the polymer, blending composition, thickness and the like may be the same or different. The layer (A) is also preferably a single layer, but it may have a multilayer structure with different polymers and blending compositions. In addition, the melt flow rate at 190 ° C. under a load of 2160 g (JIS K7210-1999, the same applies hereinafter) of the ethylene / vinyl acetate copolymer and the ethylene / (meth) acrylic acid ester copolymer is from the viewpoint of workability and mechanical strength. It is preferable that it exists in the range of 0.1-150 g / 10min.

  In the present invention, the ethylene / (meth) acrylic acid ester copolymer resin (B) may be produced by either an autoclave high pressure polymerization method or a tubular high pressure polymerization method.

    The tubular high pressure polymerization method is a method of radical polymerization using a free radical catalyst at a high pressure using a tubular reactor, for example, a method described in JP-A-62-273214 and the like. it can.

The copolymer obtained by this tubular high pressure polymerization method has (meth) acrylic acid ester content: X (mol%) and copolymer melting point: T (° C.) (melting point by DSC method, conforming to JIS K7121) The relationship of the following formula (I),
−3.0X + 125 ≧ T ≧ −3.0X + 109 (I)
The ethylene / (meth) acrylic acid ester obtained by this tubular high-pressure polymerization method has a higher melting point than a copolymer having an equivalent composition obtained by another polymerization method. A solar cell encapsulant using a copolymer is more excellent in heat resistance. In the present invention, the sealing material in the case of using a copolymer obtained by a tubular high-pressure polymerization method as the ethylene / (meth) acrylic acid ester copolymer is excellent in adhesion to glass and polyester resin.

  Here, the (meth) acrylic acid ester in the ethylene / (meth) acrylic acid ester copolymer means an acrylic acid ester or a methacrylic acid ester, and usually an alkyl ester having 1 to 10 carbon atoms of acrylic acid or methacrylic acid. In particular, alkyl esters having 2 to 8 carbon atoms are preferred. Specific examples include methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, and n-butyl methacrylate.

  In the said ethylene-vinyl acetate copolymer, when the vinyl acetate content is less than the above range, the transparency and flexibility of the solar cell encapsulant sheet are not preferred. Moreover, when a vinyl acetate content exceeding the said range is used, since the stickiness of the sheet | seat for solar cell sealing materials will become remarkable and workability will be impaired remarkably, it is unpreferable. In addition, in the ethylene / (meth) acrylic acid ester copolymer, if the content of the (meth) acrylic acid ester is less than the above range, the transparency and cross-linking properties of the solar cell encapsulant sheet are deteriorated. Therefore, it is not preferable. Moreover, when the (meth) acrylic acid ester content exceeds the above range, the stickiness of the solar cell encapsulant sheet becomes remarkable, such being undesirable.

  The thickness of the solar cell encapsulant sheet of the present invention comprising an ethylene / vinyl acetate copolymer layer and an ethylene / (meth) acrylate copolymer layer is preferably in the range of 0.2 to 2 mm. That is, when the sheet thickness is less than 0.2 mm, the solar cell element may be damaged due to impact or the like, which is not preferable. On the other hand, when the thickness exceeds the above range, the transparency of the sheet decreases, the amount of received sunlight decreases, and output may decrease, which is not preferable. Moreover, in the sheet | seat for solar cell sealing materials of this invention, the thickness of the intermediate | middle layer (A) which has ethylene / vinyl acetate copolymer as a main component, and ethylene / (meth) acrylate ester copolymer as a main component Ratio ([A) / ((b1) + (b2))] of the total thickness of both outer layers (B) (layer b1, layer b2) is 9/1 to 1/9, preferably 8/2 to 2 / It should be about 8. A sheet for a solar cell encapsulant that is excellent in such a specific lamination ratio and excellent in transparency, flexibility, crosslinkability and the like can be easily obtained. The thickness ratio of the outer layers b1 and b2 is preferably 9/1 to 1/9. In the present invention, the materials of the outer layers b1 and b2 may be the same or different.

  In the sheet | seat for laminated solar cell sealing materials of this invention, an ethylene (meth) acrylic acid ester copolymer layer is integrated in a solar cell module so that it may contact | abut to a solar cell element. In the state of being incorporated in the module, at least one of the ethylene / vinyl acetate copolymer layer (A) and the ethylene / (meth) acrylic ester copolymer layer (B), preferably the (A) layer, Both (B) layers are preferably cross-linked. Thereby, heat resistance, such as prevention of a melt flow at the time of use at high temperature, can be provided, maintaining transparency. For that purpose, it is preferable that a crosslinking agent or a crosslinking agent and a crosslinking aid are blended in at least one of the layers (A) and (B), preferably both layers, as the solar cell encapsulant sheet.

  As the crosslinking agent, it is preferable to use an organic peroxide having a decomposition temperature (temperature at which the half-life is 1 hour) of 90 to 180 ° C., particularly 100 to 150 ° C. Examples of such organic peroxides include t-butyl peroxyisopropyl carbonate, t-butyl peroxyacetate, t-butyl peroxybenzoate, dicumyl peroxide, 2,5-dimethyl-2,5-bis (t- Butylperoxy) hexane, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3, 1,1-bis (t-butylperoxy) -3, 3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, methyl ethyl ketone peroxide, 2,5-dimethylhexyl-2,5-bisperoxybenzoate, t-butyl hydroperoxide, p- Menthane hydroperoxide, benzoyl peroxide, p-chlorobenzo Peroxide, t- butyl peroxy isobutyrate, hydroxyheptyl peroxide, and di cyclohexanone peroxide.

  The crosslinking agent is blended in an amount of 0.1 to 5 parts by weight, particularly 0.5 to 3 parts by weight, based on 100 parts by weight of the ethylene / vinyl acetate copolymer or ethylene / (meth) acrylic acid ester copolymer. Is effective.

  Specific examples of the crosslinking aid include polyunsaturated compounds such as polyallyl compounds and poly (meth) acryloxy compounds. More specifically, polyallyl compounds such as triallyl isocyanurate, triallyl cyanurate, diallyl phthalate, diallyl fumarate, diallyl maleate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, etc. Examples include poly (meth) acryloxy compounds and divinylbenzene. It is effective that the crosslinking aid is blended in an amount of 5 parts by weight or less, particularly 0.1 to 3 parts by weight, based on 100 parts by weight of the ethylene / vinyl acetate copolymer or ethylene / (meth) acrylic ester copolymer. Is.

  Various other additives can be blended in the (A) and (B) layers of the sealing material sheet of the present invention, if necessary. Specific examples of such additives include adhesion imparting agents such as silane coupling agents and titanium coupling agents, antioxidants, light stabilizers, ultraviolet absorbers, colorants, light diffusing agents, flame retardants, and discoloration. An inhibitor etc. can be illustrated. Examples of the colorant include pigments, inorganic compounds and dyes. In particular, examples of white colorants include titanium oxide and zinc oxide. When blending these additives into the sealing material on the light-receiving side of the solar cell element, it is not preferable to impair the transparency, but when blending into the sealing material on the surface opposite to the light-receiving side of the solar cell element Not subject to such restrictions.

  The adhesion-imparting agent is useful for improving adhesion to a protective material, a solar cell element, and the like. Examples thereof include a silane having an amino group or an epoxy group and a hydrolyzable functional group such as an alkoxy group. A coupling agent, a titanium coupling agent, etc. can be mentioned. Specific examples of the silane coupling agent include γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropylmethyldimethoxysilane, N- (β -Aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, etc. can do. These adhesion-imparting agents are blended in an amount of 5 parts by weight or less, particularly 0.02 to 3 parts by weight, based on 100 parts by weight of ethylene / vinyl acetate copolymer or ethylene / (meth) acrylate copolymer. Is effective. In the present invention, these adhesion imparting agents such as a silane coupling agent may be blended only in the (B) layer, or may be blended in both the (A) and (B) layers.

  In addition, in order to prevent deterioration of the sheet for encapsulant based on ultraviolet rays in sunlight, an antioxidant and a light stabilizer are added to each of the ethylene / vinyl acetate copolymer layer and the ethylene / (meth) acrylate copolymer layer. It is effective to add at least one of an agent and an ultraviolet absorber. Various hindered phenols and phosphites can be used as the antioxidant. Moreover, as a light stabilizer, a hindered amine type thing can be used conveniently. Examples of the ultraviolet absorber include 2-hydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2-carboxybenzophenone, and 2-hydroxy. Benzophenones such as -4-n-octoxybenzophenone, 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole, 2- (2′-hydroxy-5-methylphenyl) benzo Salicylic acid esters such as triazole, benzotriazoles such as 2- (2′-hydroxy-5-t-octylphenyl) benzotriazole, phenylsalicylate, p-octylphenylsalicylate can be used. . These antioxidants, light stabilizers and ultraviolet absorbers are each 5 parts by weight or less, particularly 0 parts per 100 parts by weight in total of ethylene / vinyl acetate copolymer or ethylene / (meth) acrylate copolymer. It is effective to mix in the proportion of 1-3 parts by weight.

  The solar cell encapsulant sheet of the present invention can be molded by a known method using a single-layer or multilayer T-die extruder, a calendar molding machine, a single-layer or multilayer inflation molding machine, or the like. For example, each of ethylene / vinyl acetate copolymer and ethylene / (meth) acrylic acid ester copolymer is added with organic peroxide and crosslinking agent, adhesion promoter, antioxidant, light stability Additives such as additives and UV absorbers are dry-blended in advance and supplied from the hoppers of the main and secondary extruders of the multilayer T-die extruder, and the sheet is formed at a molding temperature at which the organic peroxide is not substantially decomposed. Can be obtained by multilayer extrusion molding. In addition, without preparing such a laminated sheet in advance, a sheet made of an organic peroxide and other additives added to the ethylene / vinyl acetate copolymer and an ethylene / (meth) acrylic acid ester copolymer as needed. A sheet made of an organic peroxide and other additives added to the polymer is prepared, and an ethylene / vinyl acetate copolymer is formed between the protective material and the solar cell element when the solar cell module is prepared. And an ethylene / (meth) acrylic acid ester copolymer sheet, and an ethylene / vinyl acetate copolymer sheet / ethylene / (meth) acrylic acid ester copolymer sheet / solar cell element. A sealing structure can also be formed.

  A solar cell module can be produced by fixing the solar cell element with upper and lower protective materials using the sheet for solar cell encapsulant of the present invention. Examples of such solar cell modules include various types. For example, an upper transparent protective material / a sealing material sheet / a solar cell element / a sealing material sheet / a lower protective material, which is sandwiched between both sides of a solar cell element by a sealing material sheet, a substrate such as glass The solar cell element formed on the surface is sandwiched by the sealing material from both sides of the solar cell element like upper transparent protective material / sealing material sheet / solar cell element / sealing material sheet / lower protective material. A sheet for sealing material and a lower protective material are formed on a solar cell element formed on the inner peripheral surface of the upper transparent protective material, for example, an amorphous solar cell element formed by sputtering on a fluororesin-based sheet. The thing of the structure to be made can be mentioned. In the solar cell module having such a configuration, the encapsulating layer mainly composed of ethylene / (meth) acrylic acid ester of the encapsulating material sheet of the present invention is laminated so as to contact the solar cell element.

  Solar cell elements include silicon-based materials such as single crystal silicon, polycrystalline silicon, and amorphous silicon, III-V groups such as gallium-arsenic, copper-indium-selenium, copper-indium-gallium-selenium, and cadmium-tellurium. Various solar cell elements such as II-VI group compound semiconductors can be used. The sheet | seat for sealing materials of this invention is especially useful for sealing of an amorphous silicon solar cell element.

  Examples of the upper protective material constituting the solar cell module include glass, acrylic resin, polycarbonate, polyester, and fluorine-containing resin. The lower protective material is a single or multi-layer sheet of metal or various thermoplastic resin films, for example, metals such as tin, aluminum, stainless steel, inorganic materials such as glass, polyester, inorganic vapor-deposited polyester, fluorine-containing A single layer or multilayer sheet of resin, polyolefin, etc. can be exemplified. The sheet | seat for sealing materials of this invention shows favorable adhesiveness with respect to these upper or lower protective materials.

  The solar cell module is manufactured by temporarily adhering the sealing material sheet to the solar cell element or the protective material at a temperature at which the crosslinking agent does not substantially decompose and the sealing material sheet of the present invention melts. Then, the temperature may be raised and sufficient adhesion and crosslinking may be performed. Finally, in order to obtain a solar cell module with good heat resistance, the main body layer (A) and the ethylene / (meth) acrylic acid ester copolymer containing the ethylene / vinyl acetate copolymer as the main component in the encapsulant sheet layer. Gel fraction of both layers of the sealing layer (B) mainly composed of a polymer (1 g of a sample was immersed in 100 ml of xylene, heated at 110 ° C. for 24 hours, filtered through a 20 mesh wire mesh, and the undissolved mass) Crosslinking is preferably performed so that the fraction is 70 to 98%, preferably about 80 to 95%. Therefore, the additive formulation of both layers may be selected so that these various conditions can be satisfied. For example, the type and blending amount of the crosslinking agent and the like may be selected as appropriate.

  Hereinafter, the present invention will be described in more detail with reference to examples. The raw materials used in the examples are shown in Table 1.

各種添加剤
架橋剤Ａ：２，５−ジメチル−２，５−ビス（ｔ−ブチルパーオキシ）ヘキサン
架橋剤Ｂ：ｔ−ブチルパーオキシ−２−エチルヘキシルカーボネート
架橋助剤：トリアリルイソシアヌレート
シランカップリング剤：γ−メタクリロキシプロピルトリメトキシシラン

Various additive crosslinking agents A: 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane crosslinking agent B: t-butylperoxy-2-ethylhexyl carbonate crosslinking aid: triallyl isocyanurate silane cup Ring agent: γ-methacryloxypropyltrimethoxysilane

(1) Cross-linking properties (gel fraction)
Sheets prepared using a T-die molding machine were laminated in the configuration described in Table 2, and a crosslinked sheet was prepared by heating in an oven at 145 ° C. for 20 minutes. 1 g of this cross-linked sheet is immersed in 100 ml of xylene, heated at 110 ° C. for 24 hours, filtered through a wire mesh to collect the insoluble matter, and dried and weighed to determine the gel fraction and evaluate the cross-linking properties. did. The results are shown in Table 2.

(2) Glass adhesive strength A sheet prepared using a T-die molding machine was laminated with the structure shown in Table 2, placed on 3 mm thick glass, and pasted at 145 ° C. for 20 minutes with a vacuum bonding machine. They were combined and evaluated for adhesion to glass. The measurement was performed under the conditions of a 10 mm width strip and a tensile speed of 50 mm / min. The results are shown in Table 2.

(3) Backsheet adhesive strength A sheet prepared using a T-die molding machine was laminated with the structure shown in Table 2, and a PET backsheet (Toyo Aluminum Co., Ltd.) over 145 ° C. × 20 minutes with a vacuum bonding machine. ) Manufactured toyal solar) and evaluated the adhesion to the back sheet. The measurement was performed under the conditions of a 10 mm width strip and a tensile speed of 50 mm / min. The results are shown in Table 2.

[Example 1]
To 100 parts by weight of EVA shown in Table 1, 1.0 part by weight of crosslinking agent A, 0.2 part by weight of crosslinking agent B, and 0.5 part by weight of silane coupling agent were blended (EVA blend). To 100 parts by weight of EMA, 2.0 parts by weight of crosslinking agent A and 0.5 parts by weight of crosslinking agent B are added, 2 parts by weight of triallyl isocyanurate are added, and 0.5 part by weight of silane coupling agent is blended. (EMA formulation). A (A1) layer made of 0.4 mm thick EVA composition and a (B1) layer made of 0.1 mm thick EMA composition were respectively prepared at a resin temperature of 90 ° C. using a T-die molding machine. .
Using these sheets, the glass and the back sheet were bonded together with the constitution described in Table 2, and the gel fraction, the glass adhesive strength, and the back sheet adhesive strength were evaluated.

[Example 2]
In Example 1, (A2) layer made of 0.2 mm thick EVA composition and (B2) layer made of EMA composition having a thickness of 0.2 mm were each formed at a resin temperature of 90 using a T-die molding machine. Made at ℃.
Using these sheets, the glass and the back sheet were bonded together with the constitution described in Table 2, and the gel fraction, the glass adhesive strength, and the back sheet adhesive strength were evaluated. These results are shown in Table 2.

[Comparative Example 1]
In Example 1, a (A3) layer made of an EVA composition having a thickness of 0.6 mm was formed at a resin temperature of 90 ° C. using a T-die molding machine.
Using this sheet, the glass and the back sheet were bonded together with the constitution described in Table 2, and the gel fraction, the glass adhesive strength, and the back sheet adhesive strength were evaluated. These results are shown in Table 2.

Claims (6)

  (Meth) acrylic acid ester content provided on both sides of the intermediate layer (A) whose main component is an ethylene / vinyl acetate copolymer having a vinyl acetate content of 15 to 40% by weight and the intermediate layer (A) Using a crosslinkable laminate sheet having an outer layer (B) mainly composed of 15 to 40% by weight of ethylene / (meth) acrylic acid ester copolymer and having a total thickness of 0.2 to 2 mm. Sheet for solar cell encapsulant.   The melt flow rate (JIS K7210-1999, 190 ° C., 2160 g load) of the ethylene / vinyl acetate copolymer and the ethylene / (meth) acrylate copolymer is in the range of 0.1 to 150 g / 10 min. The sheet | seat for solar cell sealing materials of Claim 1 characterized by the above-mentioned.   Crosslinking agent, crosslinking aid and silane coupling for intermediate layer (A) mainly composed of ethylene / vinyl acetate copolymer and outer layer (B) composed mainly of ethylene / (meth) acrylic acid ester copolymer The sheet | seat for solar cell sealing materials of Claim 1 or 2 formed by mix | blending the additive chosen from an agent, a ultraviolet absorber, a light stabilizer, and antioxidant.   Ratio of the total thickness of the intermediate layer (A) containing ethylene / vinyl acetate copolymer as the main component and the outer layer (B) containing ethylene / (meth) acrylic acid ester copolymer as the main component [(A) / ((B) + (B))] is 9/1 to 1/9. The solar cell encapsulant sheet according to any one of claims 1 to 3.   The gel fraction of the layer (A) mainly composed of an ethylene / vinyl acetate copolymer and the layer (B) mainly composed of an ethylene / (meth) acrylate copolymer is 70% or more, respectively. The sheet | seat for solar cell sealing materials in any one of 1-4.   The solar cell module which uses the sheet | seat for solar cell sealing materials in any one of Claims 1-5.