JP6310869B2 - PID countermeasure / power generation degradation countermeasure solar cell encapsulating sheet and PID countermeasure / power generation degradation countermeasure solar cell module - Google Patents

Description

  The present invention relates to a solar cell encapsulating sheet and a solar cell module.

  In operating a solar power generation business, the important business elements are the amount of capital investment and its maintenance costs. In order to become an energy source similar to thermal power generation, these cost reductions are essential. More importantly, there is a need for solar cell modules that do not degrade power generation for at least 40 years. At present, there are many cases where panel power generation of less than 20% is guaranteed over 20 years, but it is ideal that the power plant has no power generation degradation by performing maintenance. To that end, even if it is expressed as power generation deterioration, there are various causes, but as a result of extensive studies, it was found that there are two main causes.

  The first cause is a PID phenomenon caused by alkali metal ions released from a cover glass (white plate glass) which is a transparent substrate of the solar cell module. As a result of intensive studies by the inventors on the mechanism of occurrence of the PID phenomenon, when a sodium ion is deposited and covers about 15% or more of the total surface area of the silicon cell on the cover glass side in a widely used P-type semiconductor, pn As a result, the n layer of the structure becomes P, and as a result, the properties of the semiconductor manifested by the pn junction in a quantum mechanical manner are lost. As a result, it was clarified by destructive analysis of the solar cell module that developed the PID phenomenon in the real field that the photoelectric effect was not exhibited and the power generation was stopped.

  The second cause is “acetic acid” generated by the deterioration of the EVA sealing material that has been used for a long time. The surface electrode of the crystalline silicon cell is a paste compound mainly composed of silver. The fire-through technology completes the electrical connection between the surface electrode and silicon, and the compound contains a glass component and a lead component as an adhesive material at the interface. These materials are easily eluted with acetic acid, and when the amount of acetic acid released due to EVA deterioration increases, the surface electrode cannot efficiently collect the electrons generated in the cell, and as a result, the module It was found that the maximum output of was reduced.

  Therefore, in order to be a solar cell module that has not deteriorated in power generation for at least 20 years, as a measure against PID, it protects the migration of alkali metal ions to the cell, and seals with less acetic acid emission from the sealing material EVA. It came to the conclusion that it is necessary to cover a power generation element (solar cell) with a material.

  The above solar cell module is generally manufactured by the following procedure. First, a crystalline power generation element (hereinafter referred to as a solar cell) formed of polycrystalline silicon, single crystal silicon, or the like, or amorphous silicon or crystalline silicon is placed on a substrate such as glass on the order of several μm. A thin-film solar cell element obtained by forming a very thin film is manufactured. Next, to obtain a crystalline solar cell module, a solar cell module protective sheet (surface side transparent protective member) / solar cell encapsulant / solar cell / solar cell encapsulant / solar cell module protective sheet ( The constituent members of the back-side protection member are laminated in this order.

  On the other hand, in order to obtain a thin-film solar cell module, the constituent members of the thin-film solar cell element / solar cell sealing material / protective sheet for solar cell module (back surface side protective member) are laminated in this order. Thereafter, a solar cell module is manufactured by utilizing a laminating method in which these are vacuum-sucked and thermocompression bonded. The solar cell module manufactured in this way has weather resistance and is suitable for outdoor use such as a roof portion of a building.

  A resin composition for a solar cell encapsulant comprising an ethylene / α-olefin copolymer, an organic peroxide, and a silane coupling agent has been proposed (see, for example, Patent Document 1). This resin composition for a solar cell encapsulant is said to be excellent in heat resistance, transparency, flexibility and adhesion to glass substrates. A solar cell comprising a copolymer obtained by copolymerizing an α-olefin copolymer and an ethylene-modified unsaturated silane compound as a comonomer, and an alkoxy group-containing silane coupling agent and / or an alkoxy group-containing silicone oligomer. A resin composition for a sealing material has been proposed (for example, Patent Document 2). This resin composition for solar cell encapsulant is said to be excellent in adhesiveness with a transparent front substrate, a back surface protective sheet, and a metal film.

WO2010 / 114028 JP2011-187822

  Sealing sheet having excellent barrier property against alkali metal ions released from the cover glass of the solar cell module, preventing PID phenomenon of the solar cell module, and preventing power generation deterioration with less acetic acid generation due to deterioration of the sealing material, and the same A solar cell module using the above is provided.

<1> 1st invention The sealing sheet of 1st invention for solving the said subject is the sheet | seat width | variety of 80 cm or more,
Cyclic olefin resin film having a glass transition temperature of 75 ° C. to 95 ° C. and a thickness of 60 μm to 150 μm, an ethylene / α-olefin rubber copolymer (A), and an ethylene / acrylic acid copolymer (B) 10 to 50 parts by weight of silica is added to 100 parts by weight of a transparent olefin rubber composition blended at a blending ratio (A / B) of 60/40 to 90/10. Further, an organic peroxide is added. A transparent olefin-based rubber material containing a cross-linking agent, wherein a sheet having a thickness of 100 μm to 800 μm is laminated and integrated.

  The cyclic olefin-based resin film has a glass transition temperature of 75 ° C. or more and 95 ° C. or less, preferably 80 ° C. or more and 90 ° C. or less, and a sheet thickness of 50 μm or more and 200 μm or less, preferably 60 μm to 200 μm, Preferably, it is 75 μm to 150 μm. If it is thinner than 50 μm, the film strength is low and it cannot be wound as a sheet. If it is thicker than 200 μm, micro cracks are generated in the resin made into a solar cell module, the appearance is deteriorated, and the PID phenomenon occurs with long-term specifications, which is not preferable.

  A transparent olefin rubber material layer is integrally provided on the cyclic olefin resin film. This transparent olefin-based rubber material layer has a blending ratio (A / B) of 60/40 to 90/10 between the ethylene / α-olefin rubber copolymer (A) and the ethylene / acrylic acid copolymer (B). (A / B) is preferably 70/30 to 85/15. When the proportion of (B) exceeds 40%, the amount of acetic acid released increases, and electrodes such as solar cells may corrode and cause power generation deterioration. When the ratio of (B) is less than 10%, the transparency is lowered and the power generation amount may be reduced.

Silica (C) to be added to the olefin rubber composition is classified into anhydrous silicic acid by a dry method, hydrous silicic acid by a wet method, and synthetic silicate. The method for producing silica is as follows.
(1) A method for producing silicic anhydride.
(A) Method by decomposition of silicon halide.
(B) A method of obtaining silicic acid by heating and reducing silica sand and then oxidizing with air.
(2) Manufacturing method of hydrous silicic acid Manufacturing method by reaction of sodium silicate and sulfuric acid.
(3) Manufacturing method of synthetic silicate Manufacturing method which synthesize | combines by reaction of sodium silicate and calcium salt.

Among these silicas, dry silica is preferable from the viewpoint of transparency, and the primary particle diameter is preferably 50 nm or less, and more preferably 20 nm or less. The specific surface area of silica (C) is preferably 100 to 500 m ² / g. The compounding amount of silica (C) is 10 to 50 parts by weight, preferably 100 parts by weight of the total amount of ethylene / α-olefin rubber copolymer (A) and ethylene / acrylic acid copolymer (B). Is 15-40 parts by weight. These silicas may be surface-treated with a reactive silane such as mercaptosilane, aminosilane, hexamethyldisilazane, chlorosilane, or alkoxysilane, or a low molecular weight siloxane. The raw material of olefin rubber is milky white and is not preferable as a light-receiving surface sheet. When the silica particle diameter is larger than 50 μm, it is not transparent. Further, when the ethylene / acrylic acid copolymer is less than 10 parts by weight, the dispersibility of the silica is deteriorated and the transparency is lost.

  Furthermore, as an organic peroxide crosslinking agent (D) used by this invention, a peroxide is preferable. As the peroxide, a conventionally known peroxide that is usually used in crosslinking of rubber can be used. Specifically, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl- 2,5-di- (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexyne-3, 1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4 -Dichlorobenzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate DOO, diacetyl peroxide, lauroyl peroxide, etc. tert-butyl cumyl peroxide. Of these, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 1 , 3-bis (tert-butylperoxyisopropyl) benzene.

  Such peroxides are 2,5-dimethyl-2,5-di (tertiarybutylperoxy) hexane, 1,1-bis (tertiarybutylperoxy) -3,3,5-trimethylcyclohexane in terms of odor. 1,3-bis (tert-butylperoxyisopropyl) benzene is preferred. The blending amount is usually 0.5 to 10 parts by weight, preferably 100 parts by weight based on the total amount of the ethylene / α-olefin rubber copolymer (A) and the ethylene / acrylic acid copolymer (B). Is used in a proportion of 1 to 5 parts by weight. For safety in handling, paraffin oil or talc may be impregnated and thinned.

  The transparent olefin rubber material thus obtained has a thickness of 100 μm to 800 μm, preferably 200 μm to 600 μm. If the thickness is less than 100 μm, the power generating element may not be completely wrapped, which is not preferable. On the other hand, if the thickness is greater than 800 μm, wrinkles are generated in the sheet winding, and when the module is laid up, the cells swell due to the wrinkles and the silicon cell may break in the crystal system.

  The ethylene / α-olefin rubber copolymer used in the crosslinked rubber composition of the present invention is preferably obtained by random copolymerization of ethylene, an α-olefin having 3 to 20 carbon atoms, and a non-conjugated polyene. It is done.

  Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, Examples include 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene and the like. These α-olefins can be used alone or in combination of two or more. Among these α-olefins, α-olefins having 3 to 10 carbon atoms are preferable, and propylene, 1-butene, 4-methyl-1-pentene, 1-hexene and 1-octene are particularly preferably used.

  In the ethylene / α-olefin rubber copolymer (A), the molar ratio [ethylene / α-olefin] of ethylene and the α-olefin having 3 to 20 carbon atoms is usually 60/40 to 80/20, preferably 62. / 38 to 79/21, particularly preferably in the range of 65/35 to 78/22.

  The one minute half-life temperature of the organic peroxide is 120 to 200 ° C., and the content of the organic peroxide is 0.1 to 5 weights with respect to 100 parts by weight of the ethylene / α-olefin copolymer. Part. This includes hindered phenol stabilizers, phosphorus stabilizers and UV absorbers. The content of the hindered phenol stabilizer is 0.05 to 0.3 parts by weight with respect to 100 parts by weight of the ethylene / α-olefin copolymer. The content of the phosphorus stabilizer is 0.05 to 0.5 parts by weight with respect to 100 parts by weight of the ethylene / α-olefin copolymer. The content of the ultraviolet absorber is 0.05 to 1 part by weight with respect to 100 parts by weight of the ethylene / α-olefin copolymer. The ethylene / α-olefin copolymer, which is a constituent material of the transparent olefin rubber that is the transparent olefin rubber of the present invention, functions as a sealing material for solar cells by including an ultraviolet absorber.

  The encapsulating sheet of the first invention is a compounding ratio (A / B) of a cyclic olefin copolymer film, an ethylene / α-olefin rubber copolymer (A) and an ethylene / acrylic acid copolymer (B). Is added to 100 parts by weight of a transparent olefin rubber composition blended in a ratio of 60/40 to 90/10, and 10 parts by weight to 50 parts by weight of silica, and further contains an organic peroxide crosslinking agent. A sheet made of material is laminated and integrated. By providing this sealing sheet between the cover glass and the solar battery cell of the solar battery module, there is an effect of preventing metal ions such as sodium ions contained in the cover glass from being deposited on the solar battery cell, The onset of the PID phenomenon of the solar cell module can be prevented.

  Moreover, the sheet | seat formed with the transparent olefin type rubber material which comprises the sealing sheet of 1st invention is contacting the photovoltaic cell side. There is very little generation of acetic acid during power generation using solar cell modules. For this reason, there is very little corrosion of the electrode by acetic acid on the solar cell surface electrode, and the effect that there is no deterioration of power generation for 20 years is exhibited.

  Furthermore, by using the sealing sheet of 1st invention for a solar cell module, the PID phenomenon does not develop and the solar cell module which does not carry out power generation deterioration for at least 20 years can be provided.

<2> Second invention The sealing sheet of the second invention is
Transparent olefin rubber composition in which ethylene / α-olefin rubber copolymer (A) and ethylene / acrylic acid copolymer (B) are blended at a blending ratio (A / B) of 60/40 to 90/10 A transparent olefin rubber material containing 10 to 50 parts by weight of silica to 100 parts by weight of the product and further containing an organic peroxide cross-linking agent, and having a thickness of 100 to 800 μm is added to a glass transition temperature. Is provided on both sides (both sides) of a film of a cyclic olefin resin having a thickness of 75 to 95 ° C. and a thickness of 60 to 150 μm.

  The encapsulating sheet of the second invention is a blending ratio (A / B) of the ethylene / α-olefin rubber copolymer (A) and the ethylene / acrylic acid copolymer (B) on both sides of the cyclic olefin resin film. Is added to 100 parts by weight of a transparent olefin rubber composition blended in a ratio of 60/40 to 90/10, and 10 parts by weight to 50 parts by weight of silica, and further contains an organic peroxide crosslinking agent. They are laminated and integrated with a sheet made of material. Since the transparent olefin rubber itself is rubbery and cannot hold the sheet shape, it is essential to be integrated with another sheet (film). The effect of the present invention is manifested because it is integrated, and even if a solar cell module is manufactured using a separate existing technology, the same effect cannot be obtained. By providing this sealing sheet between the cover glass (transparent substrate) of the solar battery module and the solar battery cell, the same effect as that of the first invention can be exhibited. Moreover, the solar cell module of the structure similar to the past is easily realizable only by providing the sealing sheet of 2nd invention between a cover glass (transparent base | substrate) and a photovoltaic cell.

<3> Third Invention The sealing sheet of the third invention is characterized in that the cyclic olefin-based resin is a copolymer of ethylene and / or α-olefin and cyclic olefin.

  According to the sealing sheet of the third invention, the cyclic olefin-based resin is a copolymer of ethylene and / or α-olefin and cyclic olefin. By using ethylene among ethylene and / or α-olefin, it becomes possible to further improve the weather resistance of the sealing sheet. In addition to the effect of completely preventing PID, the effect of improving the life of the sealing sheet is exhibited. Therefore, the lifetime of the solar cell module using this sealing sheet is significantly improved.

<4> Fourth Invention A solar cell module according to a fourth invention for solving the above-described problems is characterized by using any one of the sealing sheets of the first invention to the third invention.

  Since the solar cell module of the fourth invention uses the sealing sheets of the first to third inventions, the PID phenomenon does not occur and the amount of acetic acid generated from the sealing sheet is small, so that the solar cells and the like There is no corrosion of the electrodes, and a solar cell module that does not deteriorate in power generation for at least 20 years can be realized.

<5> Fifth Invention The solar cell module of the fifth invention is characterized in that a solar cell sealing sheet using EVA is provided between the transparent substrate of the solar cell module and the sealing sheet of the first invention. A solar cell module.

  Since the solar cell module of the fifth invention is provided with an existing solar cell sealing sheet such as EVA between the solar cell module, the transparent substrate, and the sealing sheet of the first invention, Adhesive strength with the transparent substrate can be improved, and entry of water or the like into the module can be prevented. Therefore, the lifetime of the solar cell module can be improved.

<6> Sixth Invention The solar cell module of the sixth invention is characterized in that a sealing sheet for solar cells using EVA is provided between the cover glass of the solar cell module and the sealing sheet of the first invention. And

  According to the solar cell module of the sixth invention, the same effect as that of the fifth invention can be exhibited.

<7> solar cell module of the seventh aspect of the present invention seventh invention, wherein the transparent substrate of the solar cell module, between the sealing sheet of the second invention, it was only set the sealing sheet for a solar cell using EVA And

  According to the solar cell module of the seventh invention, the same effect as that of the fifth invention can be exhibited.

<8> solar cell module of the eighth invention eighth invention, wherein a cover glass for a solar cell module, between the sealing sheet of the second invention, it was only set the sealing sheet for a solar cell using EVA And

  According to the solar cell module of the eighth invention, the same effect as that of the fifth invention can be exhibited.

<9> solar cell module of the ninth invention ninth invention, the constituent members for a solar cell module including one of the sealing sheet of the first invention or found third invention is a laminate, the laminate 120 ° C. It is characterized by being molded at the above temperature.

The sealing sheet of 1st invention from 3rd invention is a laminated structure using the existing sealing sheet for solar cells between a cover glass and its sheet | seat, Comprising: It molds at the temperature of 120 degreeC or more As a result, the solar cell module can be obtained in which the respective interfaces are bonded to each other and have a PID countermeasure and power generation degradation countermeasure effect. A molding temperature of less than 120 ° C. is not preferable because a crosslinked product cannot be obtained in an economical time. The effect of the present invention cannot be obtained because it leads to a decrease in adhesive strength and an increase in acetic acid generation.

Explanatory drawing of the sealing sheet for solar cell modules of Embodiment 1 of this invention. Explanatory drawing of the sealing sheet for solar cell modules of Embodiment 2 of this invention. The block diagram of the solar cell module of Embodiment 1 using the sealing sheet of this invention. Structure explanatory drawing of a photovoltaic cell. Structure explanatory drawing of the string which electrically connected two or more photovoltaic cells. The block diagram of the solar cell module of Embodiment 2 using the sealing sheet of this invention. The block diagram of the solar cell module of Embodiment 3 using the sealing sheet of this invention. Explanatory drawing of the preparation methods of the sealing sheet of this invention. The block diagram of the conventional solar cell module.

  Hereinafter, embodiments of a sealing sheet of the present invention and a solar cell module using the sealing sheet will be described with reference to FIGS. 1 to 8.

<1> Production of Cyclic Olefin Resin Film The cyclic olefin resin film is formed into a film using a cyclic olefin resin. The cyclic olefin-based resin is not particularly limited as long as it has a glass transition temperature of 75 ° C. or higher and 95 ° C. or lower and is a polymer or copolymer having a structural unit derived from a cyclic olefin in the main chain. Examples thereof include a ring-opening polymer of a cyclic olefin or a hydrogenated product thereof, an addition copolymer of a cyclic olefin and ethylene and / or an α-olefin, or a hydrogenated product thereof. A cyclic olefin resin can be used individually by 1 type, or can also use 2 or more types together. Further, the glass transition temperature of the cyclic olefin resin used in the present invention was measured by DSC at a temperature rising rate of 10 ° C./min in accordance with JIS K7121 “Method for measuring the transition heat of plastic”.

  The cyclic olefin-based resin includes a polymer obtained by grafting and / or copolymerizing an unsaturated compound having a polar group in the polymer or the copolymer containing a structural unit derived from a cyclic olefin in the main chain.

  Examples of the polar group include a carboxyl group, an acid anhydride group, an epoxy group, an amide group, an ester group, and a hydroxyl group. Examples of the unsaturated compound having a polar group include (meth) acrylic acid and maleic acid. Acid, maleic anhydride, itaconic anhydride, glycidyl (meth) acrylate, alkyl (meth) acrylate (carbon number 1-10) ester, maleic acid alkyl (carbon number 1-10) ester, (meth) acrylamide, (meta ) 2-hydroxyethyl acrylate.

  As the cyclic olefin resin according to the present invention, a commercially available resin may be used. Commercially available cyclic olefin resins include, for example, TOPAS (registered trademark) (manufactured by TOPAS-Advanced-Polymers), Apel (registered trademark) (manufactured by Mitsui Chemicals), and metathesis using a cyclic olefin component as a starting material. Examples of the cyclic olefin polymers that are produced by ring-opening polymerization with a catalyst and hydrogenated and are commercially available include ZEONEX (registered trademark) (manufactured by ZEON CORPORATION), ZEONOR (registered trademark) (manufactured by ZEON CORPORATION), Arton ( Registered trademark) (manufactured by JSR) and the like.

（式中、Ｒ１〜Ｒ１２は、それぞれ同一でも異なっていてもよく、水素原子、ハロゲン原子、及び、炭化水素基からなる群より選ばれるものであり、
Ｒ９とＲ１０、Ｒ１１とＲ１２は、一体化して２価の炭化水素基を形成してもよく、
Ｒ９又はＲ１０と、Ｒ１１又はＲ１２とは、互いに環を形成していてもよい。
また、ｎは、０又は正の整数を示し、
ｎが２以上の場合には、Ｒ５〜Ｒ８は、それぞれの繰り返し単位の中で、それぞれ同一でも異なっていてもよい。）
環状オレフィン系共重合体のα−オレフィンとしては、特に制限はないが炭素数２〜２０のα−オレフィンが好ましい。例えば、エチレン、プロピレン、１−ブテン、１−ペンテン、１−へキセン、３−メチル−１−ブテン、３−メチル−１−ペンテン、３−エチル−１−ペンテン、４−メチル−１−ペンテン、４−メチル−１−へキセン、４，４−ジメチル−１−ヘキセン、４，４−ジメチル−１−ペンテン、４−エチル−１−へキセン、３−エチル−１−ヘキセン、１−オクテン、１−デセン、１−ドデセン、１−テトラデセン、１−ヘキサデセン、１−オクタデセン、１−エイコセン等を挙げることができる。また、これらのα−オレフィン成分は、１種単独でも２種以上を同時に使用してもよい。エチレンおよび／またはα−オレフィンの中では、エチレンの単独使用が最も好ましい。
また、環状オレフィンは、１種単独でも、また２種以上を組み合わせて使用してもよい。これらの中では、ビシクロ［２．２．１］ヘプタ−２−エン（慣用名：ノルボルネン）を単独使用することが好ましい。 As the cyclic olefin-based resin according to the present invention, a cyclic olefin-based copolymer is particularly preferably used. The cyclic olefin ring-opening polymer or its hydrogenated product may be discolored in a heated environment due to the remaining double bond. In addition, the cyclic olefin copolymer has better affinity and better adhesion than the cyclic olefin ring-opening polymer or its hydrogenated product in vulcanization adhesion with EVA.
Examples of the cyclic olefin copolymer include a copolymer containing ethylene and / or α-olefin and a structural unit derived from the cyclic olefin represented by the following general formula (I).

(In the formula, R1 to R12 may be the same or different, and are selected from the group consisting of a hydrogen atom, a halogen atom, and a hydrocarbon group,
R9 and R10, R11 and R12 may be integrated to form a divalent hydrocarbon group,
R9 or R10 and R11 or R12 may form a ring with each other.
N represents 0 or a positive integer;
When n is 2 or more, R5 to R8 may be the same or different in each repeating unit. )
The α-olefin of the cyclic olefin copolymer is not particularly limited, but an α-olefin having 2 to 20 carbon atoms is preferable. For example, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene and the like. These α-olefin components may be used alone or in combination of two or more. Among ethylene and / or α-olefin, the use of ethylene alone is most preferred.
Moreover, a cyclic olefin may be used individually by 1 type, or may be used in combination of 2 or more type. Among these, it is preferable to use bicyclo [2.2.1] hept-2-ene (common name: norbornene) alone.

The polymerization catalyst used is not particularly limited, and can be obtained by a known method using a conventionally known catalyst such as a Ziegler-Natta, metathesis, or metallocene catalyst. The cyclic olefin and α-olefin addition copolymer or hydrogenated product thereof preferably used in the present invention is preferably produced using a metallocene catalyst.
For example, in a cyclic olefin copolymer composed of ethylene and norbornene, cycloolefin / ethylene copolymers (cyclic olefin copolymers) with various glass transition temperatures (Tg) can be synthesized by changing the norbornene content. Can do. As the norbornene content is decreased and ethylene is increased, the Tg decreases accordingly.
A polymer having a glass transition temperature (Tg) of each composition can be obtained by the above-described polymerization, but can be obtained by a commercial grade melt blend. In general, in a system that is compatible with a blend of resins having different glass transition temperatures (Tg), additivity is established depending on the blend ratio. In obtaining the cyclic olefin-based resin of the present invention, in addition to the above-described polymerization method, it can be prepared by an existing grade melt blend using an extruder, and the effect of the invention is not changed at all.
In order to improve weather resistance, UV absorbers, hindered amine stabilizers, light stabilizers, etc., in order to improve long-term thermal stability, antioxidants, etc. You may mix | blend.

<2> Production of transparent olefin rubber material

<2-1> Ethylene / α-olefin copolymer The ethylene / α-olefin copolymer used in the solar cell encapsulant of the present embodiment is a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. Obtained by polymerization. As the α-olefin, usually, an α-olefin having 3 to 20 carbon atoms can be used alone or in combination of two or more. Examples of the α-olefin having 3 to 20 carbon atoms include linear or branched α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3, 3 -Dimethyl-1-butene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene and the like can be mentioned. Among these, α-olefins having 10 or less carbon atoms are preferable, and α-olefins having 3 to 8 carbon atoms are particularly preferable. Propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene and 1-octene are preferred because of their availability. The ethylene / α-olefin copolymer may be a random copolymer or a block copolymer, but a random copolymer is preferred from the viewpoint of flexibility.

  Furthermore, the ethylene / α-olefin copolymer used for the solar cell encapsulant of the present embodiment may be a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. The α-olefin is the same as described above.

<2-2> Silane Coupling Agent The solar cell encapsulating sheet of the present embodiment includes a silane coupling agent having at least one selected from the group of vinyl group, methacryl group, and acrylic group, and epoxy group-containing silane coupling. Contains agents.

  The silane coupling agent (A) having at least one selected from the group consisting of a vinyl group, a methacryl group and an acrylic group is obtained by converting the silane coupling agent to an ethylene / α-olefin copolymer by a radical generated from an organic peroxide. It is graft-modified and exhibits adhesion to a surface protection member (transparent substrate such as glass), a solar cell element (including solar cells), a metal film, a metal electrode, solder, and a back surface protection member. Content of the silane coupling agent (A) which has at least 1 type chosen from the group of the vinyl group of the solar cell sealing sheet of this embodiment, a methacryl group, and an acryl group is 100 weight part of ethylene-alpha-olefin copolymers. The amount is preferably 0.1 to 5 parts by weight, more preferably 0.1 to 4 parts by weight.

  Adhesiveness improves that content of the silane coupling agent which has at least 1 type chosen from the group of a vinyl group, a methacryl group, and an acryl group is 0.1 weight part or more.

  A conventionally well-known thing can be used for a silane coupling agent, and there is no restriction | limiting in particular. Specifically, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris (β-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-acryloxypropyltrimethoxysilane and the like can be used. Preferred examples include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, and vinyltriethoxysilane, which have good adhesion.

  The content of the epoxy group-containing silane coupling agent in the solar cell encapsulating sheet of the present embodiment is preferably 0.05 to 2.0 parts by weight with respect to 100 parts by weight of the ethylene / α-olefin copolymer. Yes, more preferably 0.05 to 1.5 parts by weight.

<2-3> Hindered amine light stabilizer It is preferable that the solar cell sealing sheet of this embodiment further contains a hindered amine light stabilizer. By including a hindered amine light stabilizer, radicals harmful to the ethylene / α-olefin copolymer can be captured, and generation of new radicals can be suppressed. Examples of hindered amine light stabilizers include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, poly [{6- (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 }] And the like, hindered piperidine compounds, and the like can be used.

  The content of the hindered amine light stabilizer in the solar cell encapsulating sheet of this embodiment is preferably 0.01 to 2.0 parts by weight with respect to 100 parts by weight of the above-mentioned ethylene / α-olefin copolymer. is there.

  The content of the hindered phenol stabilizer in the solar cell encapsulating sheet of this embodiment is preferably 0.005 to 0.1 parts by weight with respect to 100 parts by weight of the ethylene / α-olefin copolymer. More preferably, it is 0.01 to 0.1 part by weight.

<2-5> Phosphorus stabilizer It is preferable that the solar cell sealing material of this embodiment further contains a phosphorus stabilizer. When the phosphorus stabilizer is contained, decomposition of the organic peroxide during extrusion molding can be suppressed, and a sheet having a good appearance can be obtained.

  The content of the phosphorus stabilizer in the solar cell encapsulating sheet of the present embodiment is preferably 0.005 to 0.5 parts by weight with respect to 100 parts by weight of the ethylene / α-olefin copolymer.

<2-6> Ultraviolet absorber It is preferable that the solar cell sealing sheet of this embodiment further contains an ultraviolet absorber. It is preferable that content of the ultraviolet absorber in the solar cell sealing sheet of this embodiment is 0.005-5 weight part with respect to 100 weight part of ethylene * alpha-olefin copolymers. It is preferable for the content of the ultraviolet absorber to be in the above-mentioned range since the balance between weather resistance stability and crosslinking properties is excellent.

  In particular, when a crosslinking aid is contained, the content of the crosslinking aid in the solar cell encapsulating sheet of this embodiment is preferably 0.05 with respect to 100 parts by weight of the ethylene / α-olefin copolymer. -5 parts by weight, more preferably 0.1-3 parts by weight. It is preferable for the content of the crosslinking aid to be in the above-mentioned range since an appropriate crosslinked structure can be obtained, and heat resistance, mechanical properties and adhesiveness can be improved.

  As the crosslinking aid, conventionally known ones generally used for olefin rubbers can be used.

  Among these crosslinking aids, more preferred are triacrylates such as diacrylate, dimethacrylate, divinyl aromatic compound, trimethylolpropane triacrylate, tetramethylolmethane triacrylate, pentaerythritol triacrylate; trimethylolpropane trimethacrylate , Trimethacrylates such as trimethylolethane trimethacrylate; tetraacrylates such as pentaerythritol tetraacrylate and tetramethylolmethane tetraacrylate; cyanurates such as triallyl cyanurate and triallyl isocyanurate; diallyl compounds such as diallyl phthalate; triallyl compound: p -Oximes such as quinonedioxime and pp'-dibenzoylquinonedioxime: phenylmale De maleimide, such as. Further, among these, triallyl isocyanurate is particularly preferable, and the balance between the generation of bubbles and the crosslinking property of the solar cell sealing material after lamination is most excellent.

<3> Sealing material (sealing sheet)
The solar cell encapsulating sheet of the present embodiment is preferably kneaded by using a kneader or a Banbury mixer that normally prepares a rubber material, and can also be produced by melt blending with an extruder or the like. The encapsulating sheet of this embodiment is an integrated sheet of a cyclic olefin sheet and a transparent olefin rubber material layer, and the overall shape is a sheet.

  A manufacturing method thereof will be described with reference to FIGS. In this figure, the sealing sheet of this invention is obtained by the calendering method. A transparent olefin rubber material layer 16B is formed by placing a transparent olefin rubber material obtained by kneading between the roll 1 and the roll 2 adjusted to an appropriate temperature at a predetermined gap and kneading between the rolls. Can be obtained. The transparent olefin rubber material layer 16 </ b> B formed to have a constant thickness moves on the roll 3. At this time, a cyclic olefin resin film is wound around the roll 4, and a thin PET film for release is wound around the roll 5. The transparent olefin rubber material layer 16B moving on the roll 3 is passed through the roll 6 and the roll 7 in a form in which the cyclic olefin resin film 16A and the release PET film are provided on one surface of the roll 3 and is integrated as shown in FIG. The sealing sheet in the form is wound around the roll 8.

  The sealing sheet of the form of FIG. 2 uses two sealing sheets of FIG. 1 when processing the solar cell module, and arranges the cyclic olefin-based resin films 16A facing each other, and is laminated with other members. Then, the sealing sheet having the form shown in FIG. 2 is formed in the solar cell module by pressurizing and heating. This will be described again in <4> and <5>.

  Although there is no restriction | limiting in particular in the shaping | molding method of a solar cell sealing sheet, Well-known various shaping | molding methods (Cast shaping | molding, extrusion sheet shaping | molding, compression molding etc.) are employable.

  The solar cell encapsulating sheet may be composed of only the layer comprising the solar cell encapsulating sheet of this embodiment, or a layer other than the layer containing the solar cell encapsulating sheet (hereinafter referred to as “other layers”). May be included). Examples of other layers include a hard coat layer, an adhesive layer, an antireflection layer, a gas barrier layer, and an antifouling layer for protecting the front or back surface, if classified for purposes. If classified according to the material, a layer made of an ultraviolet curable resin, a layer made of a thermosetting resin, a layer made of a polyolefin resin, a layer made of a carboxylic acid-modified polyolefin resin, a layer made of a fluorine-containing resin, or a cyclic olefin resin And a layer made of an inorganic compound.

<4> Solar Cell Module The solar cell module using the solar cell encapsulating sheet of this embodiment is typically a solar cell element (also referred to as a solar cell) formed of polycrystalline silicon or the like in this embodiment. A crystalline solar cell module in which a solar cell encapsulating sheet is sandwiched and laminated, and both front and back surfaces are covered with a protective sheet. That is, a typical solar cell module includes a solar cell module protective sheet (front surface side transparent protective member) / solar cell encapsulant / solar cell element / solar cell encapsulant / solar cell module protective sheet (back side protection). Member). However, the solar cell module which is one of the preferred embodiments of the present embodiment is not limited to the above-described configuration, and a part of each of the above layers is appropriately omitted as long as the object of the present invention is not impaired. Layers other than the above can be provided as appropriate. Examples of the layer other than the above include an adhesive layer, a shock absorbing layer, a coating layer, an antireflection layer, a back surface rereflection layer, and a light diffusion layer. These layers are not particularly limited, but can be provided at appropriate positions in consideration of the purpose and characteristics of each layer.

<4-1> Crystalline Silicon Solar Cell Module FIG. 3 is a cross-sectional view schematically showing one embodiment of the solar cell module of the present invention. FIG. 3 shows an example of the configuration of the crystalline silicon solar cell module 100. As shown in FIG. 4, the solar cell module 10 includes a plurality of crystalline silicon-based solar cell elements (solar cell) 15 electrically connected by an interconnector 19 and a pair of front surface side transparent members sandwiching the solar cell module 10. A protective member (hereinafter referred to as “transparent substrate”) 11 and a back surface side protective member (hereinafter referred to as “back surface material”) 36, and between these protective members and the plurality of solar cell elements 15, the present invention. The sealing sheet 16 and an existing sealing sheet (such as EVA) are stacked and filled. Further, the back surface side protection member 36 has a configuration in which the transparent olefin rubber material layer 16B of the sealing sheet of the present invention is disposed and integrated on a polyethylene terephthalate (PET) material. This back material 36 can be manufactured by the same method as the sealing sheet of this invention. The transparent base 11, the existing sealing sheet 18, the sealing sheet 16 of the present invention, the solar battery cell 15, and the back material 36 are laminated in this order from the bottom, and obtained by thermocompression bonding (laminating). The electrode 15A on the light receiving surface of the solar battery cell 15 is in contact with and sealed with the transparent olefin rubber material layer 16B of the sealing sheet 16 of the present invention. The electrode 15B on the back surface of the solar battery cell is in contact with the transparent olefin rubber material layer 16B of the back material 36 and sealed. The electrode is a current collecting member formed on each of the light receiving surface and the back surface of the solar battery cell 15 and includes a collector wire (finger), a bus bar with a tab, a back electrode layer, and the like which will be described later.

  FIG. 4 is a plan view schematically showing a configuration example of the light receiving surface and the back surface of the solar battery cell 15. In FIG. 4, an example of the configuration of the light receiving surface 15A and the back surface 15B of the solar battery cell 15 is shown. As shown in FIG. 4 (a), the light receiving surface 15A of the solar battery cell 15 collects electric charges from the current collectors (fingers) 151 formed in a line shape and the current collector 151, and the interconnector 19 And a bus bar with tabs (bus bar) 152 connected to each other. Further, as shown in FIG. 4B, a conductive layer (back electrode) 153 is formed on the entire back surface 15B of the solar battery cell 15, and charges are collected from the conductive layer 153 on the conductive layer 153. A tabbed bus (bus bar) 154 connected to the connector 19 is formed. The line width of the collector 151 is, for example, about 0.1 mm, the line width of the tabbed bus 152 is, for example, about 2-3 mm, and the line width of the tabbed bus 154 is, for example, about 5-7 mm. is there. The thicknesses of the current collector 151, the tabbed bus 152, and the tabbed bus 154 are, for example, about 20 to 50 μm. A plurality of solar cells 15 are connected by an interconnector 19 to form a string W shown in FIG. A plurality of rows of the strings W are connected by electrode materials and supplied as solar cells 15 of the solar cell module.

  The current collector 151, the tabbed bus 152, and the tabbed bus 154 preferably include a metal having high conductivity. Examples of such highly conductive metals include gold, silver, copper, and the like. From the viewpoint of high conductivity and high corrosion resistance, silver, silver compounds, alloys containing silver, and the like are preferable. The conductive layer 153 contains not only a highly conductive metal but also a highly light reflective component such as aluminum from the viewpoint of improving the photoelectric conversion efficiency of the solar cell element by reflecting light received by the light receiving surface. It is preferable. The current collector 151, the bus bar with tabs 152, the bus bar with tabs 154, and the conductive layer 153 are made of, for example, a screen containing a conductive material paint containing the above highly conductive metal on the light receiving surface 15 </ b> A or the back surface 15 </ b> B of the solar battery cell 22. It is formed by applying to a coating thickness of 50 μm by printing, then drying, and baking at, for example, 600 to 700 ° C. as necessary. If these conventional sealing sheets (EVA etc.) are used for these electrodes, acetic acid will generate | occur | produce during use and will corrode an electrode. By using the sealing sheet of the present invention, such corrosion of the electrode can be prevented. Further, the film portion 16A of the cyclic olefin resin of the sealing sheet of the present invention prevents metal ions such as sodium ions in the cover glass from being deposited on the solar cells when a cover glass is used as the transparent substrate 11. However, the onset of PID can be eliminated.

  Since the surface side transparent protective member (transparent substrate) 11 is arranged on the light receiving surface side, it needs to be transparent. Examples of the transparent substrate 11 include a transparent glass plate and a transparent resin film. On the other hand, the back surface side protection member (back surface material) 36 does not need to be transparent, and the material is not particularly limited. In the present embodiment, as described above, the back surface material 36 has a structure in which the transparent olefin rubber material layer 16B of the sealing sheet of the present invention is disposed and integrated on, for example, a polyethylene terephthalate (PET) material. is there. Further, as the back material, a glass substrate may be used from the viewpoint of durability and transparency. Lightweight modules can be easily obtained by using Asahi Glass's Leofrex.

  FIG. 6 shows a solar cell module 200 using a sealing sheet according to another embodiment of the present invention. The sealing sheet 26 is a sealing sheet in which both surfaces of the cyclic olefin-based resin film 16A are sandwiched and integrated with the transparent olefin rubber material layer 16B. This sealing sheet is arranged as follows. The transparent substrate 11, the sealing sheet 26 of the present invention, the solar battery cell 15, and the back surface material 36 are laminated in this order from the bottom, and obtained by thermocompression processing (laminating). The electrode 15A on the light receiving surface of the solar battery cell 15 is in contact with and sealed with the transparent olefin rubber material layer 16B of the sealing sheet 26 of the present invention. Here, the sealing sheet 26 uses the two sealing sheets of FIG. 1 and arranges the cyclic olefin resin films 16 </ b> A so as to face each other. When the sealing sheet 26 is laminated and laminated with the other members, the cyclic olefin resin film is obtained. 16A melts and solidifies and integrates. As a result, even if cracks such as cracks are present in the sheet 16A, the effect of eliminating the cracks is exhibited.

  By using the sealing sheet in the form of FIG. 2, there is no generation of acetic acid from the sealing sheet, so that corrosion of the electrode of the solar battery cell can be prevented. Further, the film portion 16A of the cyclic olefin resin of the sealing sheet of FIG. 6 prevents metal ions such as sodium ions in the cover glass from being deposited on the solar cells when the cover glass is used as the transparent substrate 11. However, the onset of PID can be eliminated.

  FIG. 7 shows a solar cell module 300 using the sealing sheet of FIG. This is a configuration in which an existing sealing sheet (such as EVA) 18 is provided between the sealing sheet 26 and the transparent substrate 11 of the solar cell module in the form of FIG. In the solar cell module in the form of FIG. 6, since the existing solar cell sealing sheet 18 such as EVA is provided between the solar cell module, the transparent substrate 11 and the sealing sheet 26, the sealing sheet 26 and the transparent substrate 11. It is possible to improve the adhesive strength and prevent water and the like from entering the module. Therefore, the lifetime of the solar cell module 300 can be significantly improved.

<4-2> Thin-film silicon-based (amorphous silicon-based) solar cell module The encapsulating sheet of the present invention is not only a solar cell module using silicon cells, but also a thin-film silicon-based solar cell module having the following configuration. Applicable.

(1) Front side transparent protective member (glass substrate) / thin film solar cell element / sealing sheet / back surface material of the present invention laminated in this order; (2) front side transparent protective member / sealing layer / thin film solar cell The element / the sealing sheet / back surface material of the present invention may be laminated in this order. The surface side transparent protective member, the back surface material, and the sealing sheet of the present invention are the same as those in the “crystalline silicon solar cell module” described in (9-1).

The thin-film solar cell element in the aspect of (1) includes, for example, transparent electrode layer / pin type silicon layer / back surface electrode layer in this order. Examples of the transparent electrode layer include semiconductor-based oxides such as In ₂ O ₃ , SnO ₂ , ZnO ₂ , Cd ₂ SnO ₄ , ITO (In ₂ O ₃ with Sn added). The back electrode layer includes, for example, a silver thin film layer. Each layer is formed by a plasma CVD (chemical vapor deposition) method or a sputtering method. The sealing sheet of this invention is arrange | positioned so that a back surface electrode layer (for example, silver thin film layer) may be contact | connected. The transparent electrode layer is formed on the surface side transparent protective member.

  The thin-film solar cell element in the aspect (2) includes, for example, a transparent electrode layer / pin type silicon layer / metal foil, or a metal thin film layer (for example, a silver thin film layer) disposed on a heat-resistant polymer film. In order. Examples of the metal foil include stainless steel foil. Examples of the heat resistant polymer film include a polyimide film. The transparent electrode layer and the pin type silicon layer are formed by the CVD method or the sputtering method as described above. That is, the pin-type silicon layer is formed on a metal foil or a metal thin film layer disposed on a heat-resistant polymer film; and the transparent electrode layer is formed on a pin-type silicon layer. Moreover, the metal thin film layer arrange | positioned on a heat resistant polymer film can also be formed by CVD method or a sputtering method.

  In this case, the sealing layer is disposed between the transparent electrode layer and the front surface side transparent protective member; and between the metal foil or the heat resistant polymer film and the back surface side protective member. Thus, the sealing layer obtained from a solar cell sealing material is in contact with electrodes, such as a current collection line of a solar cell element, a bus bar with a tab, and a conductive layer. In addition, the thin-film solar cell element in the aspect (2) has a silicon layer that is thinner than a crystalline silicon-based solar cell element. Therefore, the thin-film solar cell element is damaged by pressurization when manufacturing a solar cell module or external impact when operating the module. Hard to do. For this reason, the softness | flexibility of the solar cell sealing material used for a thin film solar cell module may be lower than what is used for a crystalline silicon type solar cell module. On the other hand, since the electrode of the thin film solar cell element is a metal thin film layer as described above, when it is deteriorated by corrosion, the power generation efficiency may be significantly reduced.

<5> Manufacturing Method of Solar Cell Module The solar cell module 100 can be obtained by any manufacturing method. The solar cell module 100 is obtained by a manufacturing method including the following steps, for example. A step of obtaining a laminate in which the back material 36 (including the transparent olefin rubber material layer 16B), the plurality of solar cells 15, the sealing sheet 16 (16A, 16B) of the present invention, and the transparent substrate 11 are laminated in this order; A step of pressurizing and laminating the laminate with a laminating apparatus or the like, and simultaneously heating as necessary; after the above step, a step of further heat-treating the laminate as necessary to cure the sealing material Is the method. The sealing sheet 16 may be a sealing sheet 26 having a form as shown in FIG. In this case, the sealing sheet 26 uses two sealing sheets of FIG. 1 and is arranged in a form in which the cyclic olefin resin films 16A face each other, and is laminated with the above-mentioned other members and laminated to obtain a cyclic olefin resin. The film 16A is formed by melting and solidifying and integrating.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples.

[Example 1]
T-Butylperoxy-2- having a half-life temperature of 166 ° C. as an organic peroxide for 100 parts by weight of olefin rubber obtained by blending 85 parts by weight of EPT4021 manufactured by Mitsui Chemicals and 15 parts by weight of EPT4045 2.0 parts by weight of ethylhexyl carbonate, 0.5 parts by weight of 3-methacryloxypropyltrimethoxysilane as a silane coupling agent (A), 15 parts by weight of silica (R976S manufactured by Nippon Aerosil Co., Ltd.), tris as a crosslinking aid 1.0 part by weight of allyl isocyanurate, 0.4 part by weight of 2-hydroxy-4-normal-octyloxybenzophenone as an ultraviolet absorber, and bis (2,2,6,6-tetramethyl as a hindered amine light stabilizer -4-piperidyl) sebacate was blended in an amount of 0.2 parts by weight.

  A cyclic olefin resin film having a sheet thickness of 60 μm was obtained by using TOPAS 8007S-04 manufactured by TOPAS Advanced Polymers having a glass transition temperature of Tg of 78 ° C.

  Using the transparent olefin rubber material obtained as described above and a 60 μm cyclic olefin-based resin film, integral molding is performed by a calender molding method as shown in FIG. 8, and the thickness of the structure of FIG. 1 is 210 μm (the transparent olefin rubber layer thickness is 150 μm). ) Was obtained. A 75 μm thick PET film is attached to the side of the sealing sheet on which the transparent olefin rubber material is not attached. This PET film is peeled off when the sealing sheet of the present invention is laid up in the production process of the solar cell module.

  Using the obtained sealing sheet, a solar cell module 100 having a length of 48 was obtained by the manufacturing method described in <5> for the solar cell module having the configuration shown in FIG. Note that EVA was used as an existing adhesive sheet.

[Example 2]
100 parts by weight of olefin rubber obtained by blending 75 parts by weight of EPT4021 and 25 parts by weight of EPT4045, 25 parts by weight of silica, and a glass transition temperature of 85 ° C. with a blend ratio of TOPAS8007S-04 and TOPAS6013M-07 shown in Table 1 1 except that a 75 μm cyclic olefin-based resin film was used and sealed in a thickness of 325 μm (transparent olefin rubber layer thickness of 250 μm) as in Example 1 except that a 75 μm cyclic olefin-based resin film was used. A sheet was obtained. Using the obtained sealing sheet, a solar cell module having the configuration shown in FIG.

[Example 3]
100 parts by weight of olefin rubber obtained by blending 70 parts by weight of EPT4021 and 30 parts by weight of EPTK9720, 30 parts by weight of silica, and a glass transition temperature of 90 ° C. with a blend ratio of TOPAS8007S-04 and TOPAS6013M-07 shown in Table 1 1 except that an 80 μm cyclic olefin resin film was used and sealed in a thickness of 380 μm (transparent olefin rubber layer thickness is 300 μm) as in Example 1 except that an 80 μm cyclic olefin resin film was used. A sheet was obtained. Using the obtained sealing sheet, a solar cell module having the configuration shown in FIG.

[Example 4]
100 parts by weight of olefin rubber obtained by blending 65 parts by weight of EPT4021 and 35 parts by weight of EPT4045, 40 parts by weight of silica, and a glass transition temperature of 93 ° C. with a blend ratio of TOPAS8007S-04 and TOPAS6013M-07 shown in Table 1 1 except that a 130 μm cyclic olefin-based resin film was used and sealed in a thickness of 630 μm (transparent olefin rubber layer thickness of 500 μm) as shown in FIG. A sheet was obtained. Using the obtained sealing sheet, a solar cell module having the configuration shown in FIG.

[Example 5]
100 parts by weight of olefin rubber obtained by blending 65 parts by weight of EPT4021 and 35 parts by weight of EPT4045, 40 parts by weight of silica, and a glass transition temperature of 93 ° C. with the blend ratio of TOPAS8007S-04 and TOPAS6013M-07 shown in Table 1 1 except that a 130 μm cyclic olefin resin film was used and sealed in the configuration of FIG. 1 with a thickness of 880 μm (the transparent olefin rubber layer thickness is 750 μm) A sheet was obtained. This sealing sheet is arrange | positioned in a solar cell module with a form as shown in FIG. In this case, the sealing sheet 26 uses two sealing sheets 16 of FIG. 1 and is arranged in a form in which the cyclic olefin resin films 16A face each other. The resin film 16A is formed by melting and solidifying and integrating. Thereby, the solar cell module having the configuration of FIG. 6 is obtained. In the solar cell module having the configuration shown in FIG. 3, the adhesive sheet is EVA, but in this embodiment, the adhesive sheet is the transparent olefin rubber layer 16B. Ethylene / methyl acrylate contained in the transparent olefin rubber material ensures adhesion to the cover glass 11 of the solar cell module.

[Example 6]
100 parts by weight of olefin rubber obtained by blending 60 parts by weight of EPT4021 and 40 parts by weight of EPT4045, 40 parts by weight of silica, and a glass transition temperature of 94 ° C. with the blend ratio of TOPAS8007S-04 and TOPAS6013M-07 shown in Table 1 1 except that a 130 μm cyclic olefin resin film was used and sealed in a thickness of 480 μm (transparent olefin rubber layer thickness was 350 μm) as in Example 1 except that a 130 μm cyclic olefin resin film was used. A sheet was obtained. A solar cell module having the configuration of FIG. 3 was obtained by the production method of Example 6 using the obtained sealing sheet.

[Comparative Example 1]
Sealing with a thickness of 300 μm in the configuration of FIG. 1 in the same manner as in Example 1 except that ethylene / methyl acrylate EPT4045 is not added and a cyclic olefin resin film (PID countermeasure film (sheet)) is not used. A sheet was obtained. Since the obtained encapsulating sheet was not added with a blend resin, layup was not possible when the solar cell module having the configuration of FIG. 1 was manufactured in the same manner as in Example 1, and the solar cell module could not be manufactured.

[Comparative Example 2]
100 parts by weight of olefin rubber obtained by blending 85 parts by weight of EPT4021 and 15 parts by weight of EPT4045, 40 parts by weight of silica, and a glass transition temperature of 90 ° C. with a blend ratio of TOPAS8007S-04 and TOPAS6013M-07 shown in Table 1 1 except that a 400 μm cyclic olefin-based resin sheet was used and sealed in the configuration of FIG. 1 with a thickness of 700 μm (transparent olefin rubber layer thickness is 300 μm), except that a 400 μm cyclic olefin-based resin sheet was used. A stop sheet was obtained. A solar cell module having the configuration of FIG. 1 was obtained in the same manner as in Example 1 using the obtained sealing sheet.

[Comparative Example 3]
100 parts by weight of olefin rubber obtained by blending 70 parts by weight of EPT4021 and 30 parts by weight of EPT4045, 30 parts by weight of silica, and 300 μm cyclic olefin resin sheet (glass transition temperature Tg 90 ° C., TOPAS8007S- 1 was used in the same manner as in Example 1 except that the blend ratio of 04 and TOPAS6013M-07 was used, and a sealing sheet having a thickness of 700 μm (the transparent olefin rubber layer thickness was 400 μm) was obtained. A solar cell module having the configuration of FIG. 1 was obtained in the same manner as in Example 1 using the obtained sealing sheet.

[Comparative Example 4]
100 parts by weight of olefin rubber obtained by blending 30 parts by weight of EPT4021 and 70 parts by weight of EPT4045, 25 parts by weight of silica, and 350 μm cyclic olefin resin sheet (glass transition temperature Tg 90 ° C., TOPAS8007S- 1 was used in the same manner as in Example 1 except that the blending ratio of 04 and TOPAS6013M-07 was used, and a sealing sheet having a thickness of 600 μm (transparent olefin rubber layer thickness of 250 μm) having the configuration of FIG. 1 was obtained. A solar cell module having the configuration of FIG. 1 was obtained in the same manner as in Example 1 using the obtained sealing sheet.

[Comparative Example 5]
The solar cell module of Comparative Example 5 is a conventional 48-inch solar cell module 900 shown in FIG. 10. Cover glass from above This is a solar cell module obtained by laminating each member in the order of EVA18, solar battery cell 15, EVA18, and back material 12 by the same manufacturing method as in Example 1.

[Comparative Example 6]
100 parts by weight of olefin rubber obtained by blending 70 parts by weight of EPT4021 and 30 parts by weight of EPT4045, 20 parts by weight of silica, and 100 μm cyclic olefin-based resin film (glass transition temperature Tg 90 ° C., TOPAS8007S- 1 was used in the same manner as in Example 1 except that the blend ratio of 04 and TOPAS 6013M-07 was used, and a sealing sheet having a thickness of 190 μm (transparent olefin rubber layer thickness of 90 μm) was obtained. A solar cell module having the configuration of FIG. 1 was obtained in the same manner as in Example 1 using the obtained sealing sheet.

[Comparative Example 7]
100 parts by weight of olefin rubber obtained by blending 70 parts by weight of EPT4021 and 30 parts by weight of EPT4045, 20 parts by weight of silica, and 100 μm cyclic olefin-based resin film (glass transition temperature Tg 90 ° C., TOPAS8007S- 1 was used in the same manner as in Example 1 except that the blend ratio of 04 and TOPAS 6013M-07 was used, and a sealing sheet having a thickness of 1000 μm (a transparent olefin rubber layer thickness of 900 μm) having the configuration of FIG. 1 was obtained. Cell cracking occurred when the obtained sealing sheet was wound up. Therefore, PID power generation performance is not evaluated.

[Evaluation of winding state of the sealing sheet of the present invention]
The winding state of the sealing sheets prepared in Examples 1 to 6 and Comparative Examples 1 to 4 and Comparative Examples 6 and 7 was evaluated according to the following evaluation indices. The evaluation results are shown in Table 2.
<Winding property>
Evaluation point 3 points: There is no winding wrinkle at all on the roll for 100 m of the sealing sheet.
Evaluation point 2 points: There was one winding wrinkle on the roll for 100 m of the sealing sheet.
Evaluation point 1 point: There were two or more winding wrinkles on the roll for 100 m of the sealing sheet.

[Handling property of the sealing sheet of the present invention]
When the solar cell module of the sealing sheet created in Example 1 to Example 6 and Comparative Example 1 to Comparative Example 4 and Comparative Example 6 and Comparative Example 7 is manufactured (laminated) as a member, It was evaluated according to the following evaluation index whether or not the solar cells under the sealing sheets stacked in the electrode extraction step could be removed. The evaluation results are shown in Table 2.
<Handling>
Evaluation point 3 points: The laid-up crystalline silicon can be easily removed even after 24 hours.
Evaluation point 2 points: The laid-up crystalline silicon can be removed even after 15 minutes.
Evaluation point 1 point: The laid-up crystalline silicon cannot be removed.

[Crack of cyclic olefin copolymer sheet]
The solar cell modules obtained in Examples 1 to 6 and Comparative Examples 1 to 4 and Comparative Examples 6 and 7 were subjected to a TC test (temperature cycle test) defined in JISC8917-1998 and JISC8938-1995. Whether or not there are cracks on the 48 cells of the later 48 straight solar cell module was evaluated by the following index. The evaluation results are shown in Table 2.
<Presence of cracks>
Evaluation point 3 points: There are no cracks on the 48 cells.
Evaluation point 2 points: There are 3 or more cracks on 48 cells.
Evaluation point 1 point: There are 10 or more cracks on 48 cells.

[PID test]
The PID test was performed as follows on the solar cell modules produced in Examples 1 to 6 and Comparative Examples 1 to 7. The results are shown in Table 2.

The output of the solar cell module prepared in advance was measured with a solar simulator. Then, after putting in the chamber of 85 degreeC and 85% humidity and applying the voltage of -1000V for 2500 hours with the PID test device by an Espec company, the solar cell module was taken out and the output was again measured with the solar simulator. The power generation deterioration degree of the solar cell module was calculated by the following formula. The results are shown in Table 2.
Degree of power generation deterioration (%) = [(original maximum output−maximum output after PID test) / (original maximum output)] × 100

[Bus test]
The solar cell modules obtained in Example 1 to Example 6 and Comparative Example 1 to Comparative Example 7 were immersed in warm water at a temperature of 85 ° C. for 72 hours, and the sealing property in the solar cell module was visually confirmed, and the following indicators were used: It was evaluated with. The evaluation results are shown in Table 2.
<Sealability>
Evaluation point 3 points: The metallic luster of the horizontal bus bar has not changed compared to the original.
Evaluation point 2 points: An intermediate state between 3 evaluation points and 1 evaluation point, and cloudiness is observed.
Evaluation point 1 point: It is clouded so that it is difficult to distinguish from a white backsheet.

  Table 2 shows the results of the PID test of the solar cell modules produced in Examples 1 to 6 and Comparative Examples 1 to 7. The degree of power generation deterioration as a result of this PID test includes not only the PID phenomenon but also power generation deterioration due to corrosion of electrodes on power generation elements such as solar cells due to generation of acetic acid from the sealing sheet. Since the solar cell modules of Examples 1 to 6 use the sealing sheet of the present invention, the PID phenomenon does not occur at all, and furthermore, the generation of acetic acid from the sealing sheet is small, so that the electrodes of the power generating element are corroded. There is no power generation degradation due to.

  On the other hand, since the solar cell module of the comparative example 1 uses the sealing sheet which does not provide the cyclic olefin resin film (PID countermeasure film (sheet)), the PID power generation performance is not evaluated. In the solar far-field modules of Comparative Examples 2 to 4, the cyclic olefin resin sheet (PID countermeasure film (sheet)) provided on the sealing sheet has a thickness of 300 μm to 400 μm, and there are cracks in the sheet. Metal ions, such as sodium ions, were deposited on the solar cells through the cracks from the cover glass, causing a PID phenomenon and causing power generation deterioration of 20 to 24%. Comparative Example 5 is a conventional solar cell module that does not use the sealing sheet of the present invention. Therefore, it can be seen that the power generation deterioration degree after the PID test is 100%, and the power generation output is 0 (zero).

  The solar cells of Examples 1 to 6 exhibit the following effects in addition to eliminating power generation deterioration other than the PID phenomenon. A transparent olefin rubber material is used instead of EVA for sealing a portion in contact with a power generation element such as a solar battery cell. Therefore, since the generation of acetic acid from the sealing material in contact with the power generation element can be suppressed as much as possible, there is no deterioration of the electrode on the power generation element. For this reason, power generation deterioration due to corrosion of the electrode can also be prevented.

  According to the present invention, in a solar cell power plant for at least 20 years in the field, it is possible to prevent power generation deterioration due to PID phenomenon and power generation deterioration due to electrode corrosion due to generation of acetic acid from the sealing sheet. Can be generated as a power plant having the same life as a power plant or a hydroelectric power plant.

DESCRIPTION OF SYMBOLS 100 Solar cell module 200 Solar cell module 300 Solar cell module 11 Cover glass (transparent body)
15 Solar cell element (solar cell)
16 Sealing sheet (Embodiment 1)
16A Cyclic olefin resin film (sheet)
16B Transparent olefin rubber material sheet 16C Back material 26 Sealing sheet (Embodiment 2)
36 Composite Back Material 18 Conventional Sealing Sheet 15A Light Receiving Surface 15B Back Surface 28 Sealing Layer 19 Interconnector 151 Current Collector 152 Bus with Tab 153 Back Electrode Layer 154 Bus with Tab

Claims (9)

Cyclic olefin resin film having a glass transition temperature of 75 ° C. to 95 ° C. and a thickness of 60 μm to 150 μm, an ethylene / α-olefin rubber copolymer (A), and an ethylene / acrylic acid copolymer (B) 10 to 50 parts by weight of silica is added to 100 parts by weight of a transparent olefin rubber composition blended at a blending ratio (A / B) of 60/40 to 90/10. Further, an organic peroxide is added. A sealing sheet for a solar cell module, which is a transparent olefin rubber material containing a cross-linking agent and laminated and integrated with a sheet having a thickness of 100 μm to 800 μm. A transparent olefin rubber composition obtained by blending an ethylene / α-olefin rubber copolymer (A) and an ethylene / acrylic acid copolymer (B) at a blending ratio (A / B) of 60/40 to 90/10. A transparent olefin rubber material containing 10 to 50 parts by weight of silica to 100 parts by weight and further containing an organic peroxide crosslinking agent, and having a glass transition temperature of 100 to 800 μm. A sealing sheet for a solar cell module, which is provided on both sides (both sides) of a film of a cyclic olefin-based resin having a thickness of 75 to 95 ° C. and a thickness of 60 to 150 μm.   The encapsulating sheet for a solar cell module according to claim 1 or 2, wherein the cyclic olefin-based resin is a copolymer of ethylene and / or an α-olefin and a cyclic olefin.   A solar cell module using the sealing sheet for a solar cell module according to any one of claims 1 to 3. A solar cell module comprising a solar cell sealing sheet using EVA between the transparent substrate of the solar cell module and the sealing sheet according to claim 1. The solar cell module characterized by providing the sealing sheet for solar cells using EVA between the cover glass of a solar cell module, and the sealing sheet of Claim 1. A transparent substrate of the solar cell module, between the sealing sheet according to claim 2, the solar cell module, characterized in that the sealing sheet for a solar cell digits set using EVA. And a cover glass for a solar cell module, between the sealing sheet according to claim 2, the solar cell module, characterized in that the sealing sheet for a solar cell digits set using EVA. The components for a solar cell module including a sealing sheet as claimed in any one of claims 3 and laminate, by being composed by molding the laminate at 120 ° C. or higher temperatures A featured solar cell module.

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