JP5565520B1 - Resin composition for solar cell encapsulant, solar cell encapsulant and solar cell module - Google Patents

Abstract

A resin composition for a solar cell encapsulant that has good transparency, suppresses a decrease in adhesion to a surface protective glass even after long-term use, and can mold a solar cell encapsulant with good PID resistance. provide.
A resin composition for a solar cell encapsulant comprising an ethylene copolymer and silicoaluminophosphate. Silicoaluminophosphate is a compound obtained by treating aluminum silicate having a ratio of a silicate component and an aluminum component satisfying the composition represented by the following general formula (1) with phosphoric acid. General formula (1) SiO ₂ · nAl ₂ O ₃ (where n is 0.001 to 0.5). It is preferable that 10-99.9 mol% of the aluminum component of the general formula (1) is converted into aluminum phosphate.
[Selection] Figure 1

Description

  The present invention relates to a resin composition for a solar cell sealing material used for manufacturing a solar cell sealing material.

  From an ecological point of view, photovoltaic power generation systems (hereinafter also referred to as solar cells) are widely used as clean energy sources, and technological development aimed at further increasing the efficiency and extending the life of solar cells is being promoted. Yes.

  A solar cell is a combination of a plurality of solar cell modules, and a power generation element incorporated in the solar cell module generates power by directly converting solar energy into electrical energy using a semiconductor such as silicon. However, since the power generation function is lowered when the semiconductor is in direct contact with the outside air, the power generation element is protected by being covered with a solar cell sealing material (hereinafter also referred to as a sealing material). Currently, a crosslinked ethylene-vinyl acetate resin (hereinafter also referred to as EVA) is used as the sealing material from the viewpoints of low cost, transparency, adhesion to power generation elements, and the like. However, since EVA has low insulating properties, there is a problem that a leak current during power generation flows to the semiconductor and adversely affects the semiconductor.

  In recent years, large-scale solar power generation systems such as mega solar have been installed in various places, but for the purpose of reducing the transmission loss of the generated current, the system voltage has been raised to about 600 to 1000 V and the transmission voltage has been increased. It is out. The increase in voltage increases the potential difference between the frame and the semiconductor in the solar cell module. Further, since the surface protection glass also has a lower electrical resistance than the sealing material, the potential difference between the power generation element and the surface protection glass also increases. As a result, ions are accumulated on the surface of the power generation element of the solar cell module of the large-scale solar power generation system, and a PID (Potential Induced Degradation) phenomenon occurs in which conversion efficiency is reduced by hindering the movement of electrons. As a countermeasure against this PID phenomenon, it is necessary to prevent current leakage to the power generating element as much as possible. Therefore, it is a problem to increase the volume resistivity of the sealing material to prevent current leakage.

  Although the improvement of the PID phenomenon is not directly aimed at, the volume resistivity of the sealing material is being studied. Patent Document 1 discloses a sealing material containing a silane coupling agent having a functional group directly bonded to a silicon atom and having 4 or less carbon atoms. In Patent Documents 2 and 3, a polyolefin resin such as an ethylene-α olefin copolymer is used instead of EVA. An encapsulant is disclosed. Moreover, in patent document 4, the sealing material which mix | blended the metakaolin which baked kaolinite is disclosed.

Japanese Patent Laid-Open No. 11-54766 JP 2006-210906 A WO2012 / 046456 JP2013-64115A

  However, since a sealing material containing a specific silane coupling agent contains a silane coupling agent having a low molecular weight, the problem of volatilization of the silane coupling agent in the heating process when molding the sealing material, Or, there is a problem that the silane coupling agent bleeds out after molding, and the desired performance has not been obtained. In addition, polyolefin resin has problems of low transparency, blocking resistance and crosslinkability compared to EVA, and also phenomenon that polyolefin resin flows when solar cell module is exposed to high temperature in summer (creep phenomenon). Therefore, a sealing material using a polyolefin resin has not been common. Moreover, the sealing material blended with metakaolin has a problem that the transparency is insufficient, and considering the future increase in the capacity of solar cells, the volume resistivity is on the order of 10 15, so that the performance is insufficient.

  The present invention is a resin for solar cell encapsulant that has good transparency, suppresses a decrease in adhesion with surface protective glass even when used for a long period of time, and can form a solar cell encapsulant with good PID resistance It aims at provision of a composition and a solar cell sealing material.

  The resin composition for a solar cell encapsulant of the present invention has a configuration containing an ethylene copolymer and a silicoaluminophosphate.

  According to the present invention having the above configuration, since the silicoaluminophosphate has good dispersibility with the ethylene copolymer, the sealing material has good transparency and adhesion. Moreover, the said sealing material improved PID resistance by having increased the volume resistivity significantly by the mixing | blending of silicoaluminophosphate.

  Resin composition for solar cell encapsulant that can form a solar cell encapsulant that has good transparency, suppresses a decrease in adhesion to surface protective glass even when used for a long time, and has good PID resistance I was able to provide things.

FIG. 1 is a schematic diagram showing a cross-section in the stacking order of members used in a solar cell module. FIG. 2 is a schematic view showing a cross section illustrating a sample for a peel strength test. FIG. 3 is a schematic view showing a cross section of a sample used for the PID resistance test. FIG. 4 is a diagram for explaining an example of an IV curve for indicating an Isc value (short-circuit current value) and a Pm value (maximum output) in a PID resistance test.

  Hereinafter, the present invention will be described in detail. In the present specification, the description of “any number A or more and any number B or less” and “any number A to any number B” is a range larger than the number A and the number A, and the number B And a range smaller than the number B.

  The resin composition for a solar cell encapsulant of the present invention contains an ethylene copolymer and a silicoaluminophosphate. A resin composition for a solar cell encapsulant (hereinafter also referred to as a resin composition) is preferably formed into a sheet and used as a solar cell encapsulant. Further, the solar cell sealing material is preferably used as a member constituting the solar cell module by sandwiching and sealing (covering) the power generation element.

[Ethylene copolymer]
In the present invention, the ethylene copolymer is a copolymer obtained by polymerizing a mixture of two or more types of monomers. In the ethylene copolymer, at least one monomer used for polymerization may be an ethylene monomer. Specifically, ethylene vinyl acetate copolymer (EVA), ethylene methyl acrylate copolymer, ethylene ethyl acrylate copolymer, ethylene methyl methacrylate copolymer, ethylene ethyl methacrylate copolymer, ethylene vinyl acetate Examples thereof include an ethylene multi-component copolymer, an ethylene methyl acrylate multi-component copolymer, an ethylene ethyl acrylate multi-component copolymer, an ethylene methyl methacrylate multi-component copolymer, and an ethylene ethyl methacrylate multi-component copolymer. Among these, EVA is preferable from the viewpoint of transparency and laminating properties, EVA having a vinyl acetate content of 15 to 40 mol% is more preferable, and an ethylene vinyl acetate copolymer having a vinyl acetate content of 25 to 35 mol% is more preferable.

  In view of moldability, mechanical strength, etc., the ethylene copolymer preferably has a melt flow rate (based on JIS K7210) of 0.1 to 60 g / 10 min, more preferably 0.5 to 45 g / 10 min. . The melt flow rate is also referred to as MFR.

[Silicoaluminophosphate]
In the present invention, a sealing material using a resin composition containing silicoaluminophosphate has a high volume resistivity and improved insulation, so that the PID resistance is improved. The silicoaluminophosphate can collect conductive substances (such as ions and radicals) that reduce insulation and reduce PID resistance. The conductive material includes hydrolyzate ions (H ⁺ , COO ^−, etc.) during ethylene copolymerization, Na ⁺ ions generated by the electrolysis of glass, and metal ions derived from stabilizers (for example, Ca ²⁺ , Zn ²⁺ , Mg ²⁺ ) and the like. Silicoaluminophosphate can increase the volume resistivity of the sealing material because, for example, when the metal ions are collected, a water-insoluble metal phosphate is immediately generated by an ion exchange reaction.

A known compound can be used as the silicoaluminophosphate, but in the present invention, an aluminum silicate having a ratio of a silicic acid component and an aluminum component satisfying the composition represented by the following general formula (1) is treated with phosphoric acid. A compound in which 10 to 99.9% of the aluminum oxide component of the following general formula (1) is converted to aluminum phosphate is preferable.
General formula (1) SiO ₂ · nAl ₂ O ₃
(However, n is 0.001 to 0.5)

Silicoaluminophosphate is obtained by subjecting aluminum oxide containing a silicate component to phosphoric acid treatment and converting the aluminum component into aluminum phosphate. The silicoaluminophosphate can be obtained by subjecting a mineral mainly composed of a silicic acid component and an aluminum oxide component such as synthesized amorphous aluminum silicate or kaolin or calcined kaolin to a phosphoric acid treatment. Hereinafter, an example of a method for producing the silicoaluminophosphate using the synthesized amorphous aluminum silicate will be described. Needless to say, the production method of silicoaluminophosphate is not limited.
Silicoaluminophosphate is made of aluminum sulfate {Al ₂ to silica sol (SiO ₂ ).
(SO ₄ ) ₃ } is mixed so that the molar ratio is SiO ₂ / Al ₂ (SO ₄ ) ₃ = 20, and co-precipitated by adjusting the pH to 1 to 5 at room temperature (about 25 ° C.) and atmospheric pressure. . At this time, if the pH is lowered, the average particle diameter can be increased, and if the pH is increased, the average particle diameter can be decreased. This solution is aged at 60 ° C. for 4 hours, then washed with water and dried to obtain amorphous aluminum silicate. Next, 80 g of 85% phosphoric acid is added to 1000 ml of ion-exchanged water to form an aqueous solution, and then 100 g of amorphous aluminum silicate is added with stirring and mixed well for 5 minutes to obtain a slurry. The slurry is transferred to a stainless steel vat and evaporated to dryness at 100 ° C. overnight. Silicoaluminophosphate can be produced by pulverizing the obtained dried cake with a sample mill. The ratio of the aluminum phosphate of the manufactured silicoaluminophosphate was measured by Shimadzu sequential fluorescent X-ray analyzer LAB CENTER XRF-1700, and the aluminum contained in the sample by the FP (fundamental parameter) method mounted on the apparatus. And the weight of phosphorus were quantitatively analyzed to determine the molar ratio of the aluminum oxide component and the aluminum phosphate component.

  The silicoaluminophosphate is preferably blended in an amount of 0.01 to 1 part by weight, more preferably 0.1 to 0.5 part by weight, based on 100 parts by weight of the ethylene copolymer. By mix | blending by 0.01-1 weight part, it becomes easy to make transparency and PID resistance compatible at a high level, and adhesiveness becomes difficult to fall more. In addition, the resin composition may be a master batch for solar cell encapsulating material in which silicoaluminophosphate is blended at a high concentration. In this case, it is preferable to mix 1 to 20 parts by weight of silicoaluminophosphate with respect to 100 parts by weight of the ethylene copolymer, and more preferably 1 to 10 parts by weight. When a resin composition is produced as a master batch and a sealing material is produced using the resin composition and a diluted resin, the silicoaluminophosphate can be more uniformly dispersed in the sealing material. Finally, the silicoaluminophosphate in the sealing material is preferably about 0.01 to 1 part by weight with respect to 100 parts by weight of the ethylene copolymer.

  The average particle size of the silicoaluminophosphate is preferably 0.1 to 150 μm, and more preferably 1 to 100 μm. By being in the range of 0.1 to 150 μm, productivity, transparency, and smoothness of the sealing material can be satisfied at a higher level. The average particle diameter is a numerical value obtained by averaging about 10 to 20 particle diameters from an enlarged photograph (about 1000 to 10,000 times) of an electron microscope.

Moreover, 5-200 m < ² > / g is preferable and, as for the BET specific surface area of the said silicoaluminophosphate, 10-100 m < ² > / g is more preferable. Since a conductive substance can be further collected by being in the range of 5-200 m < ² > / g, transparency improves more and adhesiveness becomes difficult to fall more.

[Solar cell encapsulant resin composition]
In addition to the ethylene copolymer and the silicoaluminophosphate, the solar cell encapsulant resin composition of the present invention includes, as optional components, a crosslinking agent, a crosslinking aid, a silane coupling agent, an ultraviolet absorber, a light stabilizer, Additives such as antioxidants, light diffusing agents, wavelength converting agents, colorants, dispersants, and flame retardants can be blended. Moreover, the said arbitrary component can also be mix | blended when manufacturing a sealing material.

The crosslinking agent is used for preventing thermal deformation of the ethylene vinyl acetate copolymer under high temperature use. The crosslinking agent is preferably an organic peroxide. Specifically, for example, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxy-2-ethylhexyl isopropyl carbonate, tert-butyl peroxyacetate, tert-butylcumyl peroxide, 2,5-dimethyl-2,5- Di (tert-butylperoxy) hexane, di-tert-butylperoxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3, 2,5-dimethyl-2,5- Di (tert-butylperoxy) hexane, 1,1-di (tert-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-di (tert-butylperoxy) cyclohexane, 1,1- Di (tert-hexylperoxy) cyclohexane, 1,1- Di (tert-amylperoxy) cyclohexane, 2,2-di (tert-butylperoxy) butane, methyl ethyl ketone peroxide, 2,5-dimethylhexyl-2,5-diperoxybenzoate, tert-butyl hydroperoxide , P-menthane hydroperoxide, dibenzoyl peroxide, p-chlorobenzoyl peroxide, tert-butylperoxyisobutyrate, n-butyl-4,4-di (tert-butylperoxy) valerate, ethyl-3 , 3-Di (tert-butylperoxy) butyrate, hydroxyheptyl peroxide, dichlorohexanone peroxide, 1,1-di (tert-butylperoxy) 3,3,5-trimethylcyclohexane, n-butyl-4, 4-di (t ert-butylperoxy) valerate, 2,2-di (tert-butylperoxy) butane, and the like.
The crosslinking agent is preferably added in an amount of 0.05 to 3 parts by weight with respect to 100 parts by weight of the ethylene copolymer.

The crosslinking aid is used in order to efficiently advance the crosslinking reaction of the crosslinking agent. The crosslinking aid is preferably an unsaturated compound such as a polyallyl compound or a polyacryloxy compound. Specific examples include triallyl isocyanurate, triallyl cyanurate, diallyl phthalate, diallyl fumarate, diallyl maleate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, and trimethylolpropane trimethacrylate.
The crosslinking aid is preferably blended in an amount of 0.05 to 3 parts by weight with respect to 100 parts by weight of the ethylene copolymer.

The silane coupling agent is used in order to improve adhesion to a surface protective glass or a power generation element. The silane coupling agent is a compound having a functional group such as a vinyl group, an acryloxy group and a methacryloxy group, and a hydrolyzable functional group such as an alkoxy group. Specifically, for example, vinyltrichlorosilane, vinyltris (βmethoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxy Silane, γ-glycidoxypropylmethyldiethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, and the like.
The silane coupling agent is preferably added in an amount of 0.05 to 3 parts by weight based on 100 parts by weight of the total of the ethylene copolymer and the silicoaluminophosphate.

The ultraviolet absorber is used for improving weather resistance. The ultraviolet absorber is preferably a benzophenone compound, a benzotriazole compound, a triazine compound, a salicylic acid ester compound, or the like. Specifically, for example, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2′-carboxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone 2-hydroxy-4-n-octadecyloxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2-hydroxy-5-chlorobenzophenone, 2,4-dihydroxy Benzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2- (2-hydroxy- 5-methylphenyl) Nzotriazole, 2- (2-hydroxy-5-t-butylphenyl) benzotriazole, 2- (2-hydroxy-3,5-dimethylphenyl) benzotriazole, 2- (2-methyl-4-hydroxyphenyl) Benzotriazole, 2- (2-hydroxy-3-methyl-5-t-butylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-t-butylphenyl) benzotriazole, 2- (2- Hydroxy-3,5-dimethylphenyl) -5-methoxybenzotriazole, 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-5- t-butylphenyl) -5-chlorobenzotriazole, 2- [4,6-bis (2,4-dimethylphenyl) -1 3,5-triazin-2-yl] -5- (octyloxy) phenol, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyloxy) phenol, phenyl Examples include salicylate and p-octylphenyl salicylate.
The ultraviolet absorber is preferably blended in an amount of 0.01 to 3 parts by weight with respect to 100 parts by weight of the ethylene copolymer.

The light stabilizer is used for improving weather resistance, and when used in combination with an ultraviolet absorber, the weather resistance is further improved. The light stabilizer is preferably a hindered amine compound. Specifically, for example, dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [{6- (1,1,3,3 3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {{2,2,6 , 6-tetramethyl-4-piperidyl) imino}], N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2,6,6). -Pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate, bis (2,2,6,6-tetramethyl-4-piperidyl) separate, and 2- (3,5 -Di-tert-4-hydroxybenze Bis-2-n-butylmalonate (1,2,2,6,6-pentamethyl-4-piperidyl) and the like.
The light stabilizer is preferably blended in an amount of 0.01 to 3 parts by weight with respect to 100 parts by weight of the ethylene copolymer.

The said antioxidant is used in order to improve stability under high temperature. The antioxidant is preferably a monophenol compound, a bisphenol compound, a polymer phenol compound, a sulfur compound, a phosphoric acid compound, or the like. Specifically, for example, 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2'-methylene-bis- (4-ethyl-6-tert-butylphenol), 4,4'-thiobis- (3-methyl-6-tert-butylphenol) ), 4,4′-butylidene-bis- (3-methyl-6-tert-butylphenol), 3,9-bis [{1,1-dimethyl-2- {β- (3-tert-butyl-4- Hydroxy-5-methylphenyl) propionyloxy} ethyl} 2,4,8,10-tetraoxaspiro] 5,5-undecane, 1,1,3-tris- (2-methyl-4-hydro Ci-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis- {methylene-3 -(3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate} methane, bis {(3,3'-bis-4'-hydroxy-3'-tert-butylphenyl) butyric Acid} glycol ester, dilauryl thiodipropionate, dimyristyl thiodipropionate, distearyl thiopropionate, triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, 4,4′-butylidene- Bis- (3-methyl-6-tert-butylphenyl-di-tridecyl) phosphite, sa Crick neopentanetetrayl bis (octadecyl phosphite), trisdiphenyl phosphite, diisodecinorepentaerythritol diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenalene-10-oxide, 10- (3,5-di-tert-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10-dihydro-9 -Oxa-10-phosphaphenanthrene, cyclic neopentanetetraylbis (2,4-di-tert-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,6-di-tert-methyl) Phenyl) phosphite and 2,2-methylenebis (4,6 -Tert-butylphenyl) octyl phosphite and the like.
The antioxidant is preferably added in an amount of 0.05 to 3 parts by weight with respect to 100 parts by weight of the ethylene copolymer.

  The resin composition for a solar cell encapsulant of the present invention is prepared by adding an ethylene copolymer and a silicoaluminophosphate to a general high-speed shear mixer, such as a Henschel mixer or a super mixer, and then mixing them. It can be obtained by melt-kneading using a main roll, three-roll, pressure kneader, Banbury mixer, single-screw kneading extruder or biaxial kneading extruder, and extruding into a pellet. Moreover, after processing into the sheet form after the said melt-kneading, it can also shape | mold into a pellet form.

The solar cell encapsulant of the present invention is obtained by using a general molding machine such as a T-die extruder, a calendar molding machine, etc., for the solar cell encapsulant resin composition or solar cell encapsulant masterbatch. It can be manufactured by molding into a sheet. In the molding, a crosslinking agent, a crosslinking assistant, a silane coupling agent, an ultraviolet absorber, a light stabilizer and an antioxidant can be blended and molded.
The thickness of the sealing material is preferably about 0.1 to 2 mm.

  An example of the configuration of the solar cell module of the present invention will be described with reference to FIG. The solar cell module of FIG. 1 can be manufactured by stacking the surface protective glass 11, the solar cell sealing material 12 </ b> A, the power generation element 13, the solar cell sealing material 12 </ b> B, and the back surface protective member 14 in this order from the sun side, and heating and pressure bonding. . The solar cell sealing material of the present invention is used at least for the solar cell sealing material 12A. The back surface protection member 14 is preferably a sheet of glass or aluminum sandwiched between vinyl fluoride films or a sheet of aluminum sandwiched between hydrolysis-resistant polyethylene terephthalate films. In general, a vacuum laminator can be used for heating and pressurization. Needless to say, the solar cell module of the present invention is not limited to the configuration shown in FIG.

  The power generating element is made of silicon such as single crystal silicon, polycrystalline silicon, amorphous silicon, III-V group such as gallium-arsenic, copper-indium-selenium, cadmium-tellurium, II-VI group compound semiconductors, etc. Various solar cell elements can be used.

  EXAMPLES Next, although an Example of this invention is shown and it demonstrates still in detail, this invention is not limited by these. In the examples, “part” means “part by weight”, and “%” means “% by weight”.

  The raw materials used in the examples are as follows.

<Ethylene copolymer>
(A-1) EVA (vinyl acetate content: 28 mol%, MFR: 20 g / 10 min)
(A-2) EVA (vinyl acetate content: 33 mol%, MFR: 14 g / 10 min)
<Filler>
(B-1) Silicoaluminophosphate (average particle size: 5 μm, n = 0.1 in the general formula (1), 45% conversion from aluminum oxide to aluminum phosphate in terms of moles)
(B-2) Silicoaluminophosphate (average particle size: 50 μm, n = 0.1 in the general formula (1), 45% conversion from aluminum oxide to aluminum phosphate in terms of moles)
(B-3) Silicoaluminophosphate (average particle size: 100 μm, n = 0.1 in the general formula (1), 45% conversion from aluminum oxide to aluminum phosphate in terms of moles)
(B-4) Aluminum phosphate, average particle size: 1 μm
(B-5) Hydrous kaolin, average particle size: 0.4 μm
(B-6) Dry kaolin, average particle size: 0.8 μm
(B-7) calcined kaolin, average particle size: 4 μm

Example 1
[Manufacture of master batch for solar cell encapsulant]
(A-1) 95 parts of EVA and 5 parts of (B-1) silicoaluminophosphate were put into a super mixer (manufactured by Kawata) and stirred at a temperature of 25 ° C. for 3 minutes to obtain a mixture. . Next, the mixture was put into a twin screw extruder (manufactured by Nippon Placon Co., Ltd.), extruded, and cut with a pelletizer to obtain a master batch for a solar cell encapsulant.
Separately, using 91.25 parts of (A-1) EVA and 8.75 parts of light stabilizer, a stabilizer masterbatch was obtained in the same manner as described above.
Separately, 85 parts of (A-1) EVA, 5 parts of a crosslinking agent, 5 parts of a crosslinking aid, and 5 parts of a silane coupling agent were added to a super mixer and stirred to obtain a crosslinking agent master batch.

[Manufacture of solar cell encapsulant resin composition]
Using the obtained solar cell encapsulant masterbatch, stabilizer masterbatch, crosslinker masterbatch, and (A-1) EVA, (A-1) EVA was 99.9 parts, (B-1 ) A mixture with a ratio of 0.1 part of silicoaluminophosphate was obtained. Next, the mixture was put into a T-die extruder and extruded into a sheet at a temperature of 110 ° C. to prepare a solar cell sealing material having a thickness of 0.5 mm. In addition, the raw material which a solar cell sealing material contains is as follows, and the compounding quantity of a raw material is mix | blended so that it may become the following quantity with respect to 100 weight part of EVA.
・ Raw material cross-linking agent: 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane 0.6 part Cross-linking aid: triallyl isocyanurate 0.6 part Silane coupling agent: γ-methacryloxypropyl Trimethoxysilane 0.6 part Light stabilizer: N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl- 4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate 0.4 part

[Manufacture of solar cell modules]
A solar cell encapsulant 12A and a solar cell encapsulant 12B are prepared from the obtained solar cell encapsulant, and the solar cell encapsulant 12A, the power generating element 13, and the solar cell encapsulant 12B are stacked in this order. After laminating using the surface protective glass 11 and the back surface protective member 14 having a thickness of 3 mm as shown in FIG. 1, the laminate is put into a vacuum laminator, heated and pressurized under vacuum at 145 ° C. for 17 minutes, and sealed The solar cell module was produced by crosslinking. The vacuum laminator used was LM-50 × 50-S (manufactured by NPC Corporation).

(Examples 2 to 12, Comparative Examples 1 to 5)
Except having changed the ethylene copolymer and the filler to the raw materials and blending amounts shown in Tables 1 and 2, the solar cell encapsulants of Examples 2 to 12 and Comparative Examples 1 to 5 are the same as in Example 1, respectively. The solar cell module was obtained.

[Appearance evaluation]
The obtained solar cell encapsulant was used as a sample by crosslinking the encapsulant by heating and pressing under the same conditions as described above using the vacuum laminator. About the obtained sample, the external appearance was evaluated by measuring a total light transmittance and HAZE using a haze meter (made by BYK Gardner).

[Peel strength]
The adhesion was evaluated by measuring the peel strength.
First, a method for preparing a measurement sample will be described with reference to FIG. A solar cell sealing material 22 was prepared from the obtained solar cell sealing material. As shown in FIG. 2, a 3 mm thick glass plate 21, a solar cell sealing material 22, a peelable sheet 23 with a peeled surface facing the bottom surface, and a 100 μm thick polyethylene terephthalate film sheet 24 are sequentially stacked and laminated. did. The laminate was crosslinked by heating and pressing the laminate under the same conditions as described above using the vacuum laminator. The peelable sheet is half the total length of the laminate, and the polyethylene terephthalate film sheet 24 is not in close contact with the solar cell sealing material 22 for 60% of the total length of the laminate.
Next, the laminate was cut into a strip shape having a width of 1 cm and used as a sample. The sample was allowed to stand for 24 hours in an environment of a temperature of 23 ° C. and a humidity of 50% RH, and then the peel strength was measured under the conditions of a peel rate of 100 mm / min and a peel angle of 180 °. In FIG. 2, the upper side is the upper surface and the lower side is the lower surface. The peel strength was measured according to JIS K 6854-2.

[Volume resistivity]
The obtained solar cell encapsulant was used as a sample by crosslinking the encapsulant by heating and pressing under the same conditions as described above using the vacuum laminator. The volume resistivity of the sample was measured using a digital ultrahigh resistance / microammeter R8340 (manufactured by Advantest).

[Conversion efficiency retention]
For the solar cell module, first, the IV characteristics were measured and the initial conversion efficiency was calculated. Then, the solar cell module was put into a constant temperature and humidity tester set at 85 ° C. and 85% RH and left for 1000 hours, The conversion efficiency was calculated in the same manner as the initial conversion efficiency. Next, the solar cell module was put into the constant temperature and humidity tester and allowed to stand for 1000 hours under the same conditions, and the conversion efficiency was calculated in the same manner as the initial conversion efficiency. The conversion efficiency was calculated from the incident energy and the maximum output (Pm) calculated from the IV characteristic measurement and the area of the power generation element. In the evaluation, the initial conversion efficiency was set to 100, and the conversion efficiency retention was determined from the ratio of the initial conversion efficiency to the conversion efficiency after the 85 ° C. and 85% RH aging test of the solar cell module (after 1000 hours and after 2000 hours). For the measurement of the IV characteristics, solar simulator solar simulator MS-180AAA manufactured by USHIO SPEX CO., LTD. And DENKEN solar cell characteristics inspection tester DXPVT-30 were used. Further, Isc (short-circuit current) 41 obtained by measuring the IV characteristic indicates a current value when the voltage in the graph of the IV characteristic shown in FIG. 4 is 0V. Voc (open voltage) 42 indicates the voltage value when the current value is 0 A, and Pm (maximum output) 43 indicates the maximum product of the current value and the voltage value.

[PID resistance]
The PID resistance was evaluated by the following method. The results are shown in Table 4.
First, the solar cell module shown in FIG. 3 was produced. Specifically, a surface protective glass 31 having a thickness of 3 mm, a solar cell sealing material 32A, a power generation element 33, a solar cell sealing material 32B, and a back surface protective member 34 are stacked in this order, and the same as described above using the vacuum laminator. A solar cell module was obtained by thermocompression bonding under conditions, and further fixed to the metal frame 35. Next, as shown in FIG. 3, a sample was prepared by wiring the positive output terminal and the negative output terminal as a negative pole for the power generation element and the metal frame 35 as a positive pole. And the IV characteristic (Isc and Pm) and the leakage current were measured as an initial stage for the sample before the test, and it was confirmed that the initial leakage current was 0 A in all Examples and Comparative Examples.
The IV characteristics were measured using a solar cell solar simulator MS-180AAA (manufactured by Ushio Spex) and a solar cell characteristic inspection tester DXPVT-30 (manufactured by DENKEN).
In addition, as shown in FIG. 3, the leakage current is generated by setting the power generation element as a negative pole and the metal frame 35 as a positive pole and installing an output terminal, and applying a voltage of 1000 V to the power generation element from the metal frame 35 through the sealing material. And the flowing current value was measured.
Next, the sample was subjected to a PID test under the following conditions, and the IV characteristics and leakage current after the test were measured. Pm retention rate = (initial Pm value / Pm value after test) × 100
Test conditions: A temperature of 60 ° C. and a humidity of 85% RH, and an applied voltage of 1000 V for 96 hours.
In addition, in order to promote the PID phenomenon, the measurement was performed after covering the surface protective glass with water and increasing the potential difference between the power generation element and the surface protective glass.

11: Surface protection glass 12A: Solar cell sealing material 12B: Solar cell sealing material 13: Power generation element 14: Back surface protection member 21: Glass plate 22: Solar cell sealing material 23: Peelable sheet 24: Polyethylene terephthalate sheet 31 : Surface protection glass 32A: Solar cell sealing material 32B: Solar cell sealing material 33: Power generation element 34: Back surface protection member 35: Metal frame 41: Isc short-circuit current 42: Voc open circuit voltage 43: Pm maximum output

Claims (6)

Ethylene copolymer and the silicoaluminophosphate seen including,
The silicoaluminophosphate is a compound obtained by treating amorphous aluminum silicate having a ratio of a silicate component and an aluminum component satisfying the composition represented by the following general formula (1) with phosphoric acid,
General formula (1) SiO ₂ · nAl ₂ O ₃
(However, n is 0.001 to 0.5)
A resin composition for a solar cell sealing material, wherein 10 to 99.9 mol% of the aluminum oxide component of the general formula (1) is converted into aluminum phosphate . The silicone average particle diameter of the aluminosilicate phosphate is 0.1～150Myuemu, claim 1 solar cell encapsulant resin composition. The resin composition for solar cell sealing materials according to claim 1 or 2 , comprising 0.01 to 1 part by weight of the silicoaluminophosphate with respect to 100 parts by weight of the ethylene copolymer. Including an ethylene copolymer and silicoaluminophosphate,
The silicoaluminophosphate is a compound obtained by treating amorphous aluminum silicate having a ratio of a silicate component and an aluminum component satisfying the composition represented by the following general formula (1) with phosphoric acid,
General formula (1) SiO ₂ · nAl ₂ O ₃
(However, n is 0.001 to 0.5)
10-99.9 mol% of the aluminum oxide component of the general formula (1) is converted into aluminum phosphate,
The masterbatch for solar cell sealing materials which contains 1-20 weight part of said silicoaluminophosphate with respect to 100 weight part of said ethylene copolymers. The solar cell sealing material formed by shape | molding the mixture containing the resin composition for solar cell sealing materials of any one of Claims 1-3 , or the masterbatch for solar cell sealing materials of Claim 4 . The solar cell module provided with the solar cell sealing material of Claim 5 .

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