JP2010093122A - Filler sheet for solar cell module, and solar cell module using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filler sheet for a solar cell module that has superior fire resistant properties and also has superior transparency, and to provide the solar cell module using the same. <P>SOLUTION: The invention relates to: the filler sheet 3 for the solar cell module that comprises three or more transparent resin layers including two external layers 2 and at least one transparent flame resisting layers 1 between the two external layers 2, the external layers 2 containing a silane modified transparent resin as an adhesive transparent resin and the transparent flame resisting layer 1 containing a flame retarder and a transparent resin for the frame resisting layer; and the solar cell module 11 using the same. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a solar cell module filler sheet and a solar cell module using the same, and more particularly, to a solar cell module filler sheet excellent in fire resistance and transparency, and a solar cell using the same. Regarding modules.

  In recent years, solar cells as a clean energy source have attracted attention due to the growing awareness of environmental issues. Solar cell elements are often made using a single crystal silicon substrate or a polycrystalline silicon substrate, so the solar cell elements are vulnerable to physical shocks, and when solar cells are installed outdoors, they are protected from rain. There is a need to. Furthermore, since the electric output generated by one solar cell element is small, it is necessary to connect a plurality of solar cell elements in series and parallel so that a practical electric output can be taken out. For this reason, it is a common practice to produce a solar cell module by connecting a plurality of solar cell elements and enclosing them with a transparent substrate and a filler. In general, a solar cell module has a configuration in which a transparent front substrate, a filler, a solar cell element, a filler, a back surface protection sheet, and the like are sequentially laminated, and power is generated when sunlight enters the solar cell element. It has a function to do.

  Since solar cells are often used outdoors for a long period of time due to their properties, each member constituting the solar cell module has been required to have high durability and weather resistance. In recent years, in addition to these, it has been required to have fire resistance. This is because solar cells have a mechanism for generating electricity by receiving sunlight with the solar cell element, and there is a concern that abnormal heat may sometimes be generated during the power generation. The object is to prevent the solar cell module from igniting with such heat generation. In particular, since fillers mainly composed of flammable resins are used, improvement in fire resistance is required.

Therefore, Patent Documents 1 and 2 disclose a solar cell module filler sheet containing a flame retardant. By including a flame retardant in the filler, the desired fire resistance can be easily imparted to the filler, which is practically excellent.
JP 2004-214641 A JP 2007-335853 A

  However, in the methods described in Patent Documents 1 and 2, since the halogen-based flame retardant and the inorganic flame retardant which are conventionally used flame retardants are both white flame retardants, these flame retardants are used on the front side of the solar cell module. When used as a filler, it has been pointed out that the transmission of sunlight is low and the power generation efficiency is reduced. Therefore, a filler sheet for a solar cell module that is excellent in fire resistance and excellent in transparency has been desired.

  Then, the objective of this invention is providing the solar cell module using the filler sheet for solar cell modules which was excellent in fireproof property and excellent in transparency.

  As a result of intensive studies to solve the above problems, the present inventor has found that the above problems can be solved by using a filler sheet for a solar cell module having a flame retardant capable of obtaining a highly transparent resin. Thus, the present invention has been completed.

  That is, the solar cell module filler sheet of the present invention is a solar cell module filler sheet composed of three or more transparent resin layers, and includes two outer layers and two outer layers as the transparent resin layer. It has at least one transparent flame retardant layer therebetween, the outer layer contains a silane-modified transparent resin as an adhesive transparent resin, and the transparent flame retardant contains a flame retardant and a transparent resin for the transparent flame retardant layer. It is characterized by this.

  In addition, the solar cell module of the present invention includes a back surface protection sheet, a back surface filler sheet formed on the back surface protection sheet, a solar cell element formed on the back surface filler sheet, and the solar cell element. A front filler sheet formed on the front filler sheet and a transparent front substrate formed on the front filler sheet, wherein at least one of the front filler sheet and the back filler sheet is the solar cell module. It is a filler sheet for use.

  According to the present invention, it is possible to provide a solar cell module filler sheet excellent in fire resistance and transparency and a solar cell module using the same.

  Hereinafter, the filler sheet for solar cell module and the solar cell module of the present invention will be described in detail.

  FIG. 1 is a schematic view showing an example of the solar cell module filler sheet of the present invention. As illustrated in FIG. 1, the solar cell module filler sheet 3 of the present invention includes three or more transparent resin layers, and the transparent resin layer contains a silane-modified transparent resin as an adhesive transparent resin. A transparent flame retardant layer 1 containing a flame retardant and a transparent resin for a transparent flame retardant layer is provided between the two outer layers 2 and the two outer layers 2.

  According to the present invention, a transparent flame retardant layer 1 containing a flame retardant and a transparent resin for a transparent flame retardant layer, and two outer layers 2 containing an adhesive transparent resin are provided outside the transparent flame retardant layer 1. In addition, since the adhesive transparent resin is a silane-modified transparent resin, the solar cell module filler sheet 3 can be made excellent in adhesiveness, flame retardancy, and transparency. Can be laminated with sufficient adhesion strength with the front transparent substrate, the solar cell element and the back surface protection sheet constituting the solar cell module, and further, has excellent flame retardancy and transparency. Therefore, it can be set as the solar cell module which has the outstanding photoelectric conversion efficiency.

  The transparent flame retardant layer 1 used in the present invention contains a flame retardant and a transparent resin for a transparent flame retardant layer, and is not particularly limited as long as it is transparent in appearance when used in a solar cell module. Absent.

  The transparent resin for a transparent flame retardant layer contained in the transparent flame retardant layer 1 used in the present invention is a transparent resin that does not react with a flame retardant described later and can be adhered to the outer layer 2 described later with sufficient strength. If there is, it will not be specifically limited.

  In the present invention, as the transparent resin for the transparent flame retardant layer, a non-silane-modified transparent resin that is a transparent resin not containing an alkoxysilyl group can be used, or a silane-modified transparent resin can be used as appropriate. Furthermore, it is also possible to use both a non-silane-modified transparent resin and a silane-modified transparent resin. As such a silane-modified transparent resin, a resin that can be used for an adhesive transparent resin described later can be used.

  Furthermore, in this invention, it is preferable that the said transparent resin for transparent flame retardant layers and the adhesive transparent resin mentioned later are the same kind of resin. Thereby, the solar cell module filler sheet 3 of the present invention can be produced at low cost, and the adhesiveness between the transparent flame retardant layer 1 and the outer layer 2 can be made excellent. . Here, the transparent resin for the transparent flame retardant layer and the adhesive transparent resin are the same type of resin, that the transparent resin for the transparent flame retardant layer and the adhesive transparent resin are of the same type. It refers to a resin having a main chain obtained by polymerizing monomers, and does not require the same molecular weight, density, presence / absence of crosslinking, and the like.

  Examples of the non-silane-modified transparent resin include ethylene, propylene, 1-butene, isobutylene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 1-heptene, 1 Among α-olefins such as -octene, 1-nonene, and 1-decene, and other unsaturated monomers, those obtained by copolymerizing one type or two or more types can be used.

  Here, examples of the unsaturated monomer include vinyl esters such as vinyl acetate and vinyl propionate; methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, and isobutyl (meth) acrylate. , Unsaturated carboxylic acid esters such as n-butyl (meth) acrylate, isooctyl (meth) acrylate, dimethyl maleate; (meth) acrylic acid, fumaric acid, itaconic acid, monomethyl maleate, monoethyl maleate, maleic anhydride Examples thereof include unsaturated carboxylic acids such as acid and itaconic anhydride, and salts of unsaturated carboxylic acids, and styrene, (meth) acrylonitrile, vinyl alcohol, and the like may also be used. Examples of the unsaturated carboxylic acid salt include monovalent metals such as lithium, sodium and potassium, and salts of polyvalent metals such as magnesium, calcium and zinc.

  In the present invention, in particular, polyethylene, ethylene-vinyl alcohol copolymer, ethylene-unsaturated carboxylic acid ester copolymer, ethylene-unsaturated carboxylic acid copolymer, and the above-mentioned ethylene-unsaturated carboxylic acid copolymer are used. An ionomer intermolecularly bonded with a metal salt such as sodium or zinc can be preferably used, and polyethylene can be more preferably used. As a result, no nasty smell or thermal decomposition products that corrode the electrodes constituting the solar cell module are generated during heating, and when the solar cell module is produced, the vacuum lamination method is used together with the solar cell element, etc. Thus, after laminating the respective constituent materials of the solar cell module, the thermal cross-linking step of heating and cross-linking becomes unnecessary, so that the solar cell module can be produced at low cost.

  The polyethylene is not particularly limited as long as it has desired light resistance, mechanical strength, and the like, and does not require high transparency. Therefore, high-density polyethylene, medium-density polyethylene, and low-density polyethylene are not required. Any of the linear low density polyethylene can be preferably used.

  In the present invention, only one type of the non-silane-modified transparent resin may be used alone, or two or more types may be used in combination.

  Moreover, it is preferable that melting | fusing point of the said non-silane modified transparent resin is 60-130 degreeC. It is because it is excellent in moldability at the time of manufacture of the solar cell module using the filler sheet 3 for solar cell modules. In addition, as a measuring method of melting | fusing point, based on the plastics transition temperature measuring method (JISK7121), it carries out by differential scanning calorimetry (DSC). At that time, when two or more melting points exist, the higher temperature is defined as the melting point.

  Furthermore, in the present invention, the non-silane-modified transparent resin preferably has a melt mass flow rate at 190 ° C. of 0.5 g / 10 min to 10 g / 10 min, and preferably 1 g / 10 min to 8 g / 10 min. More preferred. This is because the formability of the solar cell module filler sheet 3 is excellent.

  The flame retardant used in the present invention is not particularly limited as long as desired flame retardancy can be imparted to the solar cell module filler sheet 3 and transparency as the solar cell module filler sheet 3 can be obtained. Although not intended, it is particularly preferable to use hydrotalcite.

In the present invention, as the hydrotalcite, either a natural mineral or a compound can be used. As a specific example, hydrotalcite _{(Hydrotalcite Mg 6 Al 2 (CO} 3) (OH) 16 · 4H 2 O), Con Balay Knight ^{_{(Comblanite (Ni 2+ 6 Co 3+}} 2) (CO 3) (OH) 16 · _4H 2 O), de Sawtell site ^{_{(Desautelsite Mg 6 Mn 3+ 2 (}} CO 3) (OH) 16 · 4H 2 O), Aiowaito ^{_{(Iowaite Mg 6 Fe 3+ 2 (}} OH) 16 Cl 2 · 4H 2 O), pyrolite ^{_{(Pyroaurite Mg 6 Fe 3+ 2 (}} CO 3) (OH) 16 · 4H 2 O) Ribe ^{_{site, (Reevesite Ni 6 Fe 3+ 2}} (CO 3) (OH) 16 · 4H 2 O), stitch tight (Stichtite _{mg 6 Cr 2 (CO 3)} (OH) 16 4H ₂ O), takovite _{(Tacovite Ni 6 Al 2 (OH} ) 16 (CO 3, OH) · 4H 2 O) natural mineral or various compounds such as and the like. Examples of commercially available hydrotalcites that can be easily obtained include Kyowa Chemical Industry DHT-4A, Alkamizer, Kyoward, and Microtop. Furthermore, one or more of these can be used as appropriate. By producing a solar cell module using these flame retardants, sunlight that has passed through the transparent front substrate and the solar cell module filler sheet 3 can reach the solar cell element and generate power. A solar cell module having excellent power generation efficiency can be obtained.

  In this invention, it is preferable that transparent resin for transparent flame retardant layers contains the masterbatch containing a flame retardant. Moreover, as content of the flame retardant contained in a masterbatch, 30-80 mass% is preferable, Furthermore, it is preferable that the moisture content in a masterbatch is 0.3 mass% or less, 0.1 mass% Or less, more preferably 0.06% by mass or less. If the moisture content exceeds 0.3% by mass, foaming may occur when the solar cell module filler sheet 3 is produced, and a satisfactory solar cell module filler sheet 3 is obtained. It may not be possible.

  The method for adjusting the amount of water in the masterbatch is not particularly defined, and it may be 0.3% by mass or less when the solar cell module filler sheet 3 is manufactured. For example, the moisture content is adjusted by a drying oven or the like when preparing the master batch, and then sealed in a resin bag having a water vapor barrier layer, or the moisture content is adjusted by a drying oven or the like before manufacturing the solar cell module filler sheet 3. can do.

  The transparent flame retardant layer 1 used in the present invention is not particularly limited as long as it has the above transparent resin for a transparent flame retardant layer and a flame retardant, and may contain other additives. As said other additive, a light stabilizer, a ultraviolet absorber, or a heat stabilizer can be mentioned.

  As said light stabilizer, the active species of the photodegradation start in the said transparent resin for transparent flame retardant layers is capture | acquired, and photooxidation is prevented. Specifically, one or a combination of two or more selected from hindered amine compounds, hindered piperidine compounds, and others can be used.

  As the UV absorber, harmful UV rays in sunlight are absorbed and converted into innocuous heat energy within the molecule, and the active species that initiate photodegradation in the transparent resin for the transparent flame retardant layer is excited. It is intended to prevent Specifically, benzophenone, benzotriazole, salicylate, acrylonitrile, metal complex, hindered amine, and ultrafine titanium oxide (particle diameter: 0.01 to 0.06 μm) or ultrafine zinc oxide (particles) At least one selected from the group consisting of inorganic ultraviolet absorbers such as (diameter: 0.01 to 0.04 μm) can be used.

  Examples of the heat stabilizer include tris (2,4-di-tert-butylphenyl) phosphite, bis [2,4-bis (1,1-dimethylethyl) -6-methylphenyl] ethyl ester Phosphoric acid, tetrakis (2,4-di-tert-butylphenyl) [1,1-biphenyl] -4,4′-diylbisphosphonite, and bis (2,4-di-tert-butylphenyl) penta Phosphorus heat stabilizers such as erythritol diphosphite; lactone heat stabilizers such as a reaction product of 8-hydroxy-5,7-di-tert-butyl-furan-2-one and o-xylene Can be mentioned. Moreover, these can also use 1 type or 2 types or more. In particular, it is preferable to use a phosphorus heat stabilizer and a lactone heat stabilizer in combination.

  The content of the light stabilizer, ultraviolet absorber, heat stabilizer and the like in the present invention varies depending on the particle shape, density, etc., but in the solar cell module filler sheet 3, 0.01 to 5 mass. % Is preferable.

  The thickness of the transparent flame retardant layer 1 used in the present invention is not particularly limited as long as it can exhibit sufficient transparency when formed into a solar cell module, but is in the range of 20 to 1000 μm. Is preferably within the range of 50 to 600 μm.

  The outer layer 2 used in the present invention contains an adhesive transparent resin that is a silane-modified transparent resin. When the outer layer 2 does not contain the flame retardant, excellent adhesion to the solar cell element, the back surface protection sheet, and the front transparent substrate can be maintained for a long time.

  The adhesive transparent resin used in the present invention is a silane-modified transparent resin and is not particularly limited as long as it contains an alkoxysilyl group, but in the present invention, the transparent flame retardant layer transparent resin and The adhesive transparent resin is preferably the same kind of resin. The solar cell module filler sheet 3 can be produced at low cost, and the adhesiveness between the transparent flame retardant layer 1 and the outer layer 2 can be improved.

  As the silane-modified transparent resin used as the adhesive transparent resin in the present invention, for example, a silane-modified copolymer obtained by copolymerizing an ethylenically unsaturated silane compound and a polymerization resin can be used. Such a silane-modified copolymer is preferably used in that it is easy to adjust various physical properties by changing the type and amount of the above-mentioned polymerization resin or ethylenically unsaturated silane compound as needed. Can do.

  In addition, the silane-modified copolymer used in the present invention is not particularly limited as long as it is a copolymer of an ethylenically unsaturated silane compound described later and a polymerization resin. For example, random copolymerization Even those formed by any copolymerization method of alternating copolymerization, block copolymerization, and graft copolymerization can be suitably used. In the present invention, it is particularly preferable to use a graft copolymerized product, and more preferably a graft copolymerized polymer having a polymerization resin as a main chain and an ethylenically unsaturated silane compound as a side chain. This is because the degree of freedom of the alkoxysilyl group contributing to the adhesive force is increased, and thus the adhesive force of the solar cell module filler sheet 3 can be further strengthened.

  Examples of the ethylenically unsaturated silane compound used in such a silane-modified copolymer include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, and vinyltrimethoxysilane. Mention may be made of pentyloxysilane, vinyltriphenoxysilane, vinyltribenzyloxysilane, vinyltrimethylenedioxysilane, vinyltriethylenedioxysilane, vinylpropionyloxysilane, vinyltriacetoxysilane, or vinyltricarboxysilane. . In the present invention, in particular, vinylmethoxysilane can be preferably used. It is because it is excellent in the polymerization reactivity with the resin for polymerization mentioned later.

  As the ethylenically unsaturated silane compound used in the present invention, only one type may be used alone, or two or more types may be used.

  The polymerization resin used in the silane-modified copolymer is not particularly limited as long as it can be polymerized with the ethylenically unsaturated silane compound. For example, the transparent flame retardant described above is used. A layer transparent resin and a monomer constituting the transparent resin can be used.

  Furthermore, in the present invention, it is preferable to use polyethylene as the polymerization resin used for the silane-modified copolymer, among the transparent resins for the transparent flame retardant layer. Thus, as described above, during heating, there is no off-flavor or thermal decomposition products that corrode the electrodes constituting the solar cell module, and when producing solar cell modules, solar cell elements, etc. At the same time, after the constituent materials of the solar cell module are laminated by a vacuum lamination method or the like, a heating / crosslinking step of heating / crosslinking becomes unnecessary, and thus the solar cell module can be produced at low cost.

As such polyethylene, it is preferable to use one having a low density. This is because polyethylene having a low density generally contains a large amount of side chains and can be suitably used for graft polymerization. More specifically, those density is in the range of 0.850~0.960g / cm ³ is preferably, in particular, those in the range of 0.865~0.930g / cm ³ are preferred. If the density is higher than the above range, the graft polymerization becomes insufficient, and the solar cell module filler sheet 3 of the present invention may not be able to be provided with a desired adhesive force, while the density is higher than the above range. This is because if it is low, the mechanical strength of the solar cell module filler sheet 3 of the present invention may be low.

  In the present invention, one kind of the above polyethylene may be used as a simple substance, or two or more kinds may be mixed and used.

  The content of the ethylenically unsaturated silane compound in the silane-modified copolymer used in the present invention is preferably in the range of 0.001 to 4 parts by mass with respect to 100 parts by mass of the polymerization resin. It is preferable that it exists in the range of 0.01-3 mass parts. If the content of the ethylenically unsaturated silane compound is less than 0.001 part by mass, the adhesion to the solar cell element, the back surface protective sheet and the transparent electrode substrate may be insufficient, while the ethylenically unsaturated silane compound may be insufficient. When there is more content of a saturated silane compound than 4 mass parts, there exists a possibility that adhesiveness may not change and cost may become high.

  The melting point of the silane-modified copolymer is preferably 60 to 110 ° C. It is because it is excellent in moldability at the time of manufacture of the solar cell module using the filler sheet 3 for solar cell modules. In addition, as a measuring method of melting | fusing point, the method similar to the above can be used.

  The silane-modified copolymer is not particularly limited as long as it has a melting point in the above range, but a melt mass flow rate at 190 ° C. is 0.5 g / 10 min to 10 g / 10 min. What is preferably 1 g / 10 min to 8 g / 10 min is more preferable. This is because the moldability of the solar cell module filler sheet 3 of the present invention can be improved. In addition, as a measurement of a melt mass flow rate, the method similar to the above can be used.

  The method for producing the silane-modified copolymer used in the present invention is not particularly limited as long as a silane-modified copolymer having a desired amount of alkoxysilyl group can be obtained. Examples thereof include a method in which an ethylenically unsaturated silane compound and the above-mentioned polymerization resin are heated and melted together with a radical polymerization initiator. The heat-melt mixing method is not particularly limited as long as it can be heat-melted and mixed under desired temperature conditions and the like, and a known heat-melt mixing device such as an extruder can be used. Moreover, as heating temperature in the manufacturing method of the said silane modified copolymer, although it changes with materials, such as the ethylenically unsaturated silane compound to be used, it is preferable to exist in the range of 150-300 degreeC, and 180-270. It is preferably in the range of ° C. This is because the silane-modified copolymer is easily gelled due to crosslinking of the silanol group portion by heating.

  Examples of the radical polymerization initiator include hydroperoxides such as diisopropylbenzene hydroperoxide and 2,5-dimethyl-2,5-di (hydroperoxy) hexane; di-t-butyl peroxide, t -Butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-peroxy) hexyne-3 Dialkyl peroxides such as bis-3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, benzoyl peroxide, o-methylbenzoyl peroxide, 2,4-dichlorobenzoyl peroxide Class: t-butyl peroxyacetate, t-butyl peroxyacetate Oxy-2-ethylhexanoate, t- butyl peroxypivalate, t- butyl peroxy octoate. t-butyl peroxyisopropyl carbonate, t-butyl peroxybenzoate, di-t-butyl peroxyphthalate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-2, Peroxyesters such as 5-di (benzoylperoxy) hexyne-3; organic peroxides such as methyl peroxides such as methyl ethyl ketone peroxide and cyclohexanenon peroxide, or azobisisobutyronitrile, azobis ( 2,4-dimethylvaleronitrile) and the like.

  The content of the radical polymerization initiator is not particularly limited as long as it can polymerize the ethylenically unsaturated silane compound and the polymerization resin, but the ethylenically unsaturated silane compound and It is preferable that 0.001-0.1 mass% is contained in the mixture of the said resin for superposition | polymerization. When the content of the radical polymerization initiator is less than 0.001% by mass, radical polymerization between the ethylenically unsaturated silane compound and the polymerization resin may hardly occur.

  The outer layer 2 used in the present invention is not particularly limited as long as it contains the above-mentioned adhesive transparent resin and does not contain a flame retardant. For example, the outer layer 2 contains an additive resin and other additives. It may be.

  The additive resin used in the present invention is not particularly limited as long as it can be uniformly mixed with the adhesive transparent resin, but is the same as the polymerization resin used for the adhesive transparent resin. It is preferable to use those. Cost reduction can be achieved by using such an additive resin.

  In the present invention, the content of the additive resin is preferably in the range of 0.01 to 9900 parts by mass, particularly in the range of 0.1 to 2000 parts by mass, with respect to 100 parts by mass of the adhesive transparent resin. preferable. When the content of the additive resin is less than 0.01 parts by mass, the cost may be disadvantageous. On the other hand, when the content of the additive resin is greater than 9900 parts by mass, This is because the adhesive force of the battery module filler sheet 3 may be insufficient.

  The melting point of the additive resin is preferably 80 to 130 ° C. It is because it is excellent in moldability at the time of manufacture of the solar cell module using the filler sheet 3 for solar cell modules.

  In the present invention, the additive resin preferably has a melt mass flow rate at 190 ° C. of 0.5 g / 10 min to 10 g / 10 min, more preferably 1 g / 10 min to 8 g / 10 min. . It is because it is excellent in the moldability of the filler sheet 3 for solar cell modules of this invention.

  Examples of other additives contained in the outer layer 2 used in the present invention include a light stabilizer, an ultraviolet absorber, a heat stabilizer, and the like, and the same one as the transparent flame retardant layer 1 is used. Can do. However, the ultraviolet absorber does not include a metal complex salt, an inorganic type such as ultrafine titanium oxide or ultrafine zinc oxide. This is because the inorganic ultraviolet absorber has a hygroscopic property, so that the adhesiveness of the outer layer 2 may be lowered.

  Moreover, it is preferable that the outer layer 2 used for this invention is a thing which does not contain a silanol condensation catalyst substantially. This is because the silanol condensation catalyst promotes the condensation reaction between the silanol groups, so that the adhesiveness of the outer layer 2 may be reduced in a short period of time. Note that the silanol condensation catalyst substantially does not contain the silanol condensation catalyst, specifically, the silanol condensation catalyst such as dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dioctate, dioctyltin dilaurate is the total resin constituting the outer layer 2. It is preferably 0.05 parts by mass or less, more preferably in the range of 0 to 0.01 parts by mass, and even more preferably 0 parts by mass with respect to 100 parts by mass.

  The Si (silicon) content in the outer layer 2 used in the present invention is preferably in the range of 8 to 3500 ppm, more preferably in the range of 10 to 3000 ppm, and particularly in the range of 50 to 2000 ppm. Even more preferably. When the amount of Si is less than the above range, the adhesive strength of the solar cell module filler sheet 3 becomes insufficient, and there is a possibility that a solar cell module excellent in stability with time of adhesion cannot be produced. This is because if the amount of Si is larger than the above range, it may be disadvantageous in terms of cost. Here, the amount of the polymerized Si is determined by ICP emission analysis using a high-frequency plasma emission analyzer (ICPS8100 manufactured by Shimadzu Corporation) after the ash content of the resin sheet is alkali-melted and dissolved in pure water. This is a value measured by quantifying the amount of polymerized Si.

  Further, the gel fraction of the outer layer 2 used in the present invention is preferably 30% or less, more preferably 10% or less, and even more preferably 0%. When it is 30% or less, for example, after the solar cell module is formed using the solar cell module filler sheet 3 including the outer layer 2, it is easy to reuse the solar cell module filler sheet 3. Because it becomes. On the other hand, if the gel fraction is higher than the above range, the workability during the production of the solar cell module may be reduced, or the adhesion strength with the transparent electrode substrate, the solar cell element and the back surface protective sheet may be insufficient. It is.

  As a method for measuring such a gel fraction, the solar cell module filler sheet 3 is peeled and separated into the transparent flame retardant layer 1 and the outer layer 2, and then 1 g of the outer layer 2 is weighed, and 80 mesh Put in a wire mesh bag. Next, a sample with the wire mesh is put into a Soxhlet extractor, and xylene is refluxed at the boiling point. After 10 hours of continuous extraction, a method is used in which the sample is taken out together with the wire mesh, weighed after the drying process, mass comparison before and after extraction is performed, the mass% of residual insoluble matter is measured, and this is used as the gel fraction.

  The thickness of the outer layer 2 used in the present invention is not particularly limited as long as it can exhibit sufficient adhesiveness and the like when a solar cell module is used, but within the range of 5 to 1000 μm. It is preferable that the thickness is 20 to 600 μm.

  The solar cell module filler sheet 3 of the present invention comprises three or more transparent resin layers, and the transparent resin layer includes at least one transparent flame retardant layer 1 between two outer layers 2. For example, the number of transparent resin layers is not particularly limited. For example, the transparent resin layer 1 may have two or more transparent flame retardant layers 1, and if the desired effect of the present invention is obtained, the outer layer 2 and the transparent flame retardant layer may be obtained. You may have transparent resin layers other than one.

  In addition, the thickness of the solar cell module filler sheet 3 of the present invention is not particularly limited as long as it can exhibit sufficient strength and the like when used as a solar cell module. It is preferably in the range of 1000 μm, more preferably 100 to 600 μm.

  Further, in the present invention, the ratio of the thickness of the transparent flame retardant layer 1 and the outer layer 2 (transparent flame retardant layer / outer layer) is preferably in the range of 95/5 to 5/95, More preferably, it is in the range of 10-50 / 50. If the thickness ratio is smaller than the above range, it may not be sufficiently flame retardant. On the other hand, if the thickness ratio is larger than the above range, the outer layer 2 is formed uniformly. May be difficult. The thickness of the outer layer 2 is not the sum of the thicknesses of the outer layers 2 laminated on both sides of the transparent flame retardant layer 1, but the thickness per one layer of the outer layer 2. Moreover, when it has two or more transparent flame retardant layers 1, the thickness per layer of the said transparent flame retardant layer 1 is said.

  The fireproof property of the solar cell module filler sheet of the present invention is appropriately prepared according to the type of solar cell module produced using the solar cell module filler sheet. In particular, in the present invention, the linear burning rate (mm / min) evaluated using the horizontal burning test (HB) of JIS standard K7247 is 55 mm / min or less when the thickness of the test piece is 600 μm or less. Is preferable, it is more preferable that the flame does not spread to the 100 mm mark, and it is even more preferable not to ignite.

Here, the evaluation method of the linear burning rate is as follows.
(Evaluation method of linear burning rate)
A vertical line is drawn perpendicular to the long side at 25 mm and 100 mm from the end of each test piece (13 × 125 mm) to which the flame is applied, and a marked line is drawn. The test piece is placed horizontally with the clamp held at the end. The height of the test flame is set to 20 mm, and the gas flow rate is set to 105 mL / min. The burner is tilted at 45 ° to the end not clamped by the specimen clamp, and flame is applied. Start measuring time when the tip of the combustion flame reaches the 25mm mark. If the test piece continues to burn after the test flame is moved away, record the burning time from the 25 mm mark to the 100 mm mark and the damaged distance. The burning rate V of each specimen is the following equation:
V = 60L / t
(In the formula, V is a linear burning rate (mm / min), L is a distance damaged by a flame (mm), and t is time (s)).

  The method for producing the solar cell module filler sheet 3 of the present invention is not particularly limited as long as the transparent flame retardant layer 1 and the outer layer 2 can be laminated with good adhesion. For example, the transparent flame retardant layer 1 and the outer layer 2 are formed by a film forming method such as an extrusion method, a cast molding method, a T-die method, a cutting method, and an inflation method. After the film is formed alone, the layers are laminated, or the transparent flame retardant layer 1 and the outer layer 2 are co-extruded to form the transparent flame retardant layer 1 and the outer layer 2. The method of manufacturing the filler sheet 3 for solar cell modules can be mentioned. Further, for example, a tenter method, a tubular method, or the like may be used to extend in a uniaxial or biaxial direction.

  FIG. 2 is a schematic diagram of a layer configuration showing an example of the solar cell module of the present invention. The solar cell module 11 of the present invention includes a back surface protection sheet 12, a back surface filler sheet 13 formed on the back surface protection sheet 12, a solar cell element 14 formed on the back surface filler sheet 13, and a solar cell. A front filler sheet 15 formed on the element 14 and a transparent front substrate 16 formed on the front filler sheet 15, wherein at least one of the front filler sheet 15 and the back filler sheet 13 is The solar cell module filler sheet 3 according to the present invention, and the front filler sheet 15 is particularly preferably the solar cell module filler sheet 3.

  According to the present invention, by using the solar cell module filler sheet 3 of the present invention, the transparent electrode substrate 16, the solar cell element 14, and the back surface protective sheet 12 have sufficient adhesion strength and stably. Can be stacked. Moreover, the said solar cell module filler sheet 3 has the transparent flame-resistant layer 1, and shall have the outstanding flame retardance. Furthermore, since it has the outstanding transparency, the sunlight which permeate | transmitted the transparent front substrate 16 permeate | transmits the front filler sheet | seat 15, and can reach | attain the solar cell element 14 efficiently.

  Moreover, the gel fraction of the outer layer 2 of the solar cell module filler sheet 3 included in the solar cell module 11 of the present invention, that is, the outer layer 2 of the solar cell module filler sheet 3 after the solar cell module 11 is formed. The gel fraction is preferably 30% or less, more preferably 10% or less, and even more preferably 0%. When the gel fraction is higher than the above range, for example, after the solar cell module 11 is formed using the solar cell module filler sheet 3 including the outer layer 2, the solar cell module filler sheet 3 is reused. This is because it becomes difficult. Moreover, it is because the contact | adhesion intensity | strength with the transparent electrode substrate 16, the solar cell element 14, and the back surface protection sheet 12 may become inadequate.

The solar cell element 14 used in the present invention is not particularly limited, and a general solar cell element 14 can be used. Specifically, crystalline silicon solar electronic elements such as single crystal silicon type solar cell elements and polycrystalline silicon type solar cell elements, amorphous silicon solar electronic elements composed of single junction type or tandem structure type, gallium arsenide (GaAs), etc. III-V group compound semiconductor solar electronic devices such as indium phosphorus (InP), II-VI group compound semiconductor solar electronic devices such as cadmium telluride (CdTe) and copper indium selenide (CuInSe ₂ ), organic solar cell devices and the like are used. be able to.

  As the solar cell element 14 used in the present invention, a thin film polycrystalline silicon solar cell element, a thin film microcrystalline silicon solar cell element, a hybrid element of a thin film crystalline silicon solar cell element and an amorphous silicon solar cell element, etc. Can be used.

  The back protective sheet 12 used in the present invention is not particularly limited as long as it has desired weather resistance such as heat resistance, light resistance, and water resistance. As such a back surface protection sheet 12, an insulating resin film, a metal plate, etc. are used suitably, for example. In particular, in the present invention, it is preferable to use the insulating resin film.

  Examples of the resin film include polyethylene resin, polypropylene resin, cyclic polyolefin resin, fluorine resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), and acrylonitrile-butadiene-styrene copolymer (ABS). Resin), polyvinyl chloride resin, fluorine resin, poly (meth) acrylic resin, polycarbonate resin, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyamide resins such as various nylons, polyimide resins, Polyamideimide resin, polyarylphthalate resin, silicone resin, polysulfone resin, polyphenylene sulfide resin, polyethersulfone resin, polyurethane resin, acetal resin, cellulose Mention may be made of a film made of fat. In particular, in the present invention, it is preferable to use a film made of a fluorine resin, a cyclic polyolefin resin, a polycarbonate resin, a poly (meth) acrylic resin, or a polyester resin.

  Moreover, as such a resin film, a biaxially stretched resin film can also be used.

  Further, the resin film may have a configuration in which a plurality of films are laminated. Examples of the configuration in which such a plurality of films are laminated include a configuration in which a gas barrier film having an inorganic vapor deposition film is laminated, and a configuration in which a tough film is laminated.

  As thickness of the back surface protection sheet 12 used for this invention, it is usually preferable to exist in the range of 12-200 micrometers, and it is still more preferable that it is in the range of 25-150 micrometers.

  The transparent front substrate 16 used in the present invention is not particularly limited as long as it is a substrate having sunlight permeability. For example, a glass plate, a fluorine resin, a polyamide resin (various nylons), a polyester resin, Various resin films such as polyethylene resin, polypropylene resin, cyclic polyolefin resin, polystyrene resin, (meth) acrylic resin, polycarbonate resin, acetal resin, and cellulose resin can be used.

  In addition, the thickness of the transparent front substrate 16 used in the present invention is not particularly limited as long as the desired strength can be achieved, but usually it is preferably in the range of 12 to 7000 μm, and particularly preferably in the range of 25 to 4000 μm. preferable.

  In the solar cell module 11 of the present invention, other layers can be arbitrarily added and laminated on the basis of solar absorptivity, reinforcement, and other purposes. Examples of such other layers include low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer resin, ethylene. -Ethyl acrylate copolymer, ethylene-acrylic acid or methacrylic acid copolymer, methyl pentene polymer, polybutene resin, polyvinyl chloride resin, polyvinyl acetate resin, polyvinylidene chloride resin, vinyl chloride-vinylidene chloride Copolymer, Poly (meth) acrylic resin, Polyacrylonitrile resin, Polystyrene resin, Acrylonitrile-styrene copolymer (AS resin), Acrylonitrile-butadiene-styrene copolymer (ABS resin), Polyester Resin, polyamide system From films or sheets of known resins such as fats, polycarbonate resins, polyvinyl alcohol resins, saponified ethylene-vinyl acetate copolymers, fluorine resins, diene resins, polyacetal resins, polyurethane resins, nitrocellulose, etc. It can be arbitrarily selected and used.

  In the present invention, after laminating the transparent front substrate 16, the front filler layer 15, the solar cell element 14, the back filler layer 13, and the back protective sheet 12 in this order, as a method of thermocompression bonding these, The method is not particularly limited as long as the structure can be closely attached, and generally known methods can be used. As such a method, for example, the transparent front substrate 16, the front filler layer 15, the solar cell element 14, the back filler layer 13, and the back protective sheet 12 are laminated in this order, and then these are integrated into a vacuum. The lamination method etc. which are attracted | sucked and thermocompression-bonded can be illustrated.

  In general, the lamination temperature when using the above lamination method is preferably within a range of 90 ° C to 230 ° C, and particularly preferably within a range of 110 ° C to 190 ° C.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

(Preparation of silane-modified transparent resin)
With respect to 98 parts by mass of metallocene linear low density polyethylene (hereinafter referred to as “M-LLDPE”) having a density of 0.898 g / cm ³ and a melt mass flow rate at 190 ° C. of 2 g / 10 min. Then, 2 parts by mass of vinyltrimethoxysilane and 0.1 part by mass of dicumyl peroxide as a radical initiator were mixed, heated and stirred at 200 ° C. to obtain a silane-modified transparent resin.

(Preparation of additive masterbatch)
For 85 parts by mass of powder obtained by pulverizing Ziegler linear low density polyethylene having a density of 0.920 g / cm ³ , 2.5 parts by mass of a hindered amine light stabilizer, 7.5 parts by mass of a benzophenone ultraviolet absorber, An additive master batch was prepared by mixing 5 parts by mass of a phosphorus-based heat stabilizer, melting, processing and pelletizing.

(Preparation of flame retardant masterbatch A)
To 40 parts by mass of powder obtained by pulverizing Ziegler linear low density polyethylene having a density of 0.920 g / cm ³ , 60 parts by mass of hydrotalcite was mixed, melted, processed, and pelletized. Furthermore, after putting in a 90 degreeC drying oven for 10 hours and drying a pellet and confirming that the moisture content is 0.08 mass%, it sealed-packed in the resin bag containing aluminum.

(Preparation of flame retardant masterbatch B)
After pelletizing with the same composition as the master batch A, it was packed in a resin bag as it was without being put in a drying oven. It was confirmed that the water content was 3.5% by mass.

(Preparation of antimony trioxide flame retardant masterbatch)
40 parts by mass of powder obtained by pulverizing Ziegler linear low-density polyethylene having a density of 0.920 g / cm ³ is mixed with 60 parts by mass of antimony trioxide (Daifunen EH-931, manufactured by Dainichi Seika Co., Ltd.) and melted.・ Processed and pelletized master batch was obtained.

(Preparation of magnesium hydroxide flame retardant masterbatch)
To 40 parts by mass of powder obtained by pulverizing Ziegler linear low density polyethylene having a density of 0.920 g / cm ³ , 60 parts by mass of magnesium hydroxide was mixed and melted and processed to obtain a pelletized master batch. .

(Preparation of filler sheet for solar cell module)
In the production of the solar cell module filler sheet, a φ25 mm extruder capable of forming a layer structure of two types and three layers and a film molding machine having a T die having a width of 300 mm were used. The resin in the hopper A is supplied to the first and third layers (outer layers), and the resin in the hopper B is supplied to the second layer (transparent flame retardant layer).

Example 1
As the adhesive transparent resin, 20 parts by mass of the silane-modified transparent resin, 80 parts by mass of Ziegler linear low density polyethylene having a density of 0.920 g / cm ³ , and 5 parts by mass of an additive master batch are mixed, and the film It was put into hopper A of the molding machine.

Next, 95 parts by mass of Ziegler linear low density polyethylene having a density of 0.920 g / cm ³ as a transparent resin for a transparent flame retardant layer, 5 parts by mass of an additive master batch, and 30 parts by mass of a flame retardant master batch A Were mixed and put into hopper B of the film molding machine.

  Next, using the film forming machine, a sheet having a thickness of 400 μm at an extrusion temperature of 230 ° C. and a take-off speed of 3 m / min is set so that the first and third layers have a thickness of 100 μm and the second layer has a thickness of 200 μm. The second layer is a transparent flame retardant layer containing a transparent resin for a transparent flame retardant layer and a flame retardant, and the first layer and the third layer sandwiching the transparent flame retardant layer are adhesive transparent resins. The filler sheet for solar cell modules which is the outer layer which has was obtained. In addition, said film formation was able to be implemented without trouble.

(Production of solar cell module)
A glass plate (transparent front substrate) having a thickness of 3 mm, a filler sheet for the solar cell module having a thickness of 400 μm (surface), a solar cell element made of polycrystalline silicon, and a filling for the solar cell module having a thickness of 400 μm. Laminated sheet (back surface protection sheet) comprising a material sheet (back surface), a 38 μm thick polyvinyl fluoride resin sheet (PVF), a 30 μm thick polyethylene terephthalate sheet and a 38 μm thick polyvinyl fluoride resin sheet (PVF) ) Are laminated in this order, and the solar cell element surface is faced up, and is subjected to pressure bonding at 150 ° C. for 15 minutes with a vacuum laminator for production of the solar cell module to produce a solar cell module.

[Example 2]
Instead of the flame retardant master batch A used in Example 1, a film was formed in the same manner as in Example 1 except that the flame retardant master batch B was used to obtain a solar cell module filler sheet.

[Comparative Example 1]
Instead of the flame retardant masterbatch A used in Example 1, a film was formed in the same manner as in Example 1 except that an antimony trioxide flame retardant masterbatch was used to obtain a solar cell module filler sheet. .

[Comparative Example 2]
Instead of the flame retardant masterbatch A used in Example 1, a film was formed in the same manner as in Example 1 except that a magnesium hydroxide flame retardant masterbatch was used to obtain a solar cell module filler sheet. .

[Characteristic evaluation]
The following tests were conducted on the solar cell module filler sheets in Examples 1 and 2 and Comparative Examples 1 and 2 and the solar cell modules produced using them. The measurement results of each test are shown in Table 1 below.

(1) Film-forming property In the film-forming with the single-layer film forming machine which has the said T dice, the film-forming condition was confirmed visually and the result is shown in Table 1.

(2) Measurement of initial power generation efficiency Based on JIS standard C8917, the initial power generation efficiency of the solar cell modules manufactured using the solar cell module filler sheets of Examples 1 and 2 and Comparative Examples 1 and 2 was measured. The results are shown in Table 1.

(3) Measurement of horizontal combustion test Based on JIS standard K7247, test flame height 20 ± 1 mm, gas flow rate 105 mL / min for the solar cell module filler sheets of Examples 1 and 2 and Comparative Examples 1 and 2 above. A horizontal combustion test was conducted using a test flame having a temperature rise time of the copper block of 44 ± 2 seconds, and the presence or absence of ignition was confirmed. Table 1 shows the results.

(4) Horizontal combustion test based on UL94 For the solar cell module filler sheets of Examples 1 and 2 and Comparative Examples 1 and 2, a horizontal combustion test is performed based on UL94 to determine the state of ignition and the linear combustion rate. The results are shown in Table 1. Here, for the evaluation in the horizontal combustion test, according to the HB standard, the line burning speed between the 25 mm and 100 mm marked lines is 75 mm / min or less, and the fire does not spread to the 100 mm marked line, otherwise Was marked with x.

  In Comparative Examples 1 and 2 having no transparent flame retardant layer, the initial power generation efficiency was low. In contrast, in Examples 1 and 2, the initial power generation efficiency was good. Moreover, although Example 2 is excellent in fireproofing and transparency, it has foaming in film-forming property compared with Example 1, and the moisture content of the resin for fillers is 0.3 mass% or less. Example 1 was the best.

It is the schematic which shows an example of the filler sheet for solar cell modules of this invention. It is the schematic of the layer structure which shows an example of the solar cell module of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent flame retardant layer 2 Outer layer 3 Filler sheet | seat 11 for solar cell modules Solar cell module 12 Back surface protection sheet 13 Back surface material sheet 14 Solar cell element 15 Front surface material sheet 16 Transparent front substrate

Claims (10)

A solar cell module filler sheet comprising three or more transparent resin layers,
As the transparent resin layer, it has two outer layers and at least one transparent flame retardant layer between the two outer layers,
The outer layer contains a silane-modified transparent resin as an adhesive transparent resin, and the transparent flame retardant layer contains a flame retardant and a transparent resin for a transparent flame retardant layer.   The filler sheet for a solar cell module according to claim 1, wherein the flame retardant is hydrotalcite.   The said transparent resin for transparent flame retardant layers contains the masterbatch containing the said flame retardant, The moisture content of the said masterbatch is 0.3 mass% or less, The filler sheet for solar cell modules of Claim 1 or 2 .   The said transparent resin for transparent flame retardant layers is a silane modified transparent resin and / or a non-silane modified transparent resin, The solar cell module filler sheet as described in any one of Claims 1-3.   The filler sheet for a solar cell module according to claim 4, wherein the transparent resin for the transparent flame retardant layer is polyethylene.   The said transparent resin for transparent flame retardant layers and the said adhesive transparent resin are the same kind of resin, The filler sheet | seat for solar cell modules as described in any one of Claims 1-5.   The silane-modified transparent resin is a silane-modified polymer obtained by graft polymerization of an ethylenically unsaturated silane compound and a polymerization resin, and the polymerization resin is polyethylene. The filler sheet for solar cell modules described.   The gel fraction of the said silane modified transparent resin is 30% or less, The solar cell module filler sheet as described in any one of Claims 1-7. A back protection sheet,
A back surface filler sheet formed on the back surface protection sheet;
A solar cell element formed on the back surface filler sheet;
A front filler sheet formed on the solar cell element;
A transparent front substrate formed on the front filler sheet,
The solar cell module according to claim 1, wherein at least one of the front filler sheet and the back filler sheet is the solar cell module filler sheet according to claim 1.   The solar cell module according to claim 9, wherein the front filler sheet is a solar cell module filler sheet according to claim 1.

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