JP2010093119A - Filler layer for solar cell module, and solar cell module using the same - Google Patents

Abstract

A filler sheet for a solar cell module that can suppress white turbidity of a resin for a filler even when the temperature changes due to a hot spot phenomenon or the like, and has excellent adhesion and transparency, and a solar cell using the same Provide modules.
An intermediate layer containing a transparent resin for an intermediate layer and a nucleating agent dispersed in the transparent resin for the intermediate layer, and the intermediate layer 1 are sandwiched, and a silane-modified transparent resin is used as the transparent resin for the adhesive layer. It is the solar cell module 11 using the filler sheet for solar cell modules which has the contact bonding layer 2 to contain.
[Selection] Figure 1

Description

  The present invention relates to a filler sheet for a solar cell module and a solar cell module using the same, and more specifically, even when there is a temperature change due to a hot spot phenomenon or the like, it is possible to suppress white turbidity of the resin for the filler, and adhesion TECHNICAL FIELD The present invention relates to a solar cell module filler sheet having excellent properties and transparency, and a solar cell module using the same.

  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 is manufactured by using a lamination method or the like 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 these are vacuum-sucked and thermocompression bonded.

  At present, ethylene-vinyl acetate copolymer resin (EVA) having a thickness of 100 μm to 1500 μm is used as the most common material from the viewpoint of workability, workability, manufacturing cost, and other aspects. Yes. However, the filler made of ethylene-vinyl acetate copolymer resin has a problem that the adhesive strength with the solar cell element is not always sufficient, and peeling occurs when used for a long time. Therefore, as a method of imparting adhesiveness to the filler, a method of polymerizing a silane compound on a resin has been proposed (see, for example, Patent Document 1 and Patent Document 2).

  On the other hand, in the solar cell module installed outdoors, among the plurality of solar cell elements of the solar cell module that is generating power, when one solar cell element is in the shadow of something and power generation becomes insufficient, This solar cell element becomes a resistor. At this time, a potential difference of the product of the resistance value and the flowing current is generated in both electrodes of the solar cell element. That is, a reverse bias voltage is applied to the solar cell element, and the solar cell element generates heat. Such a phenomenon is called a hot spot.

  And when a hot spot phenomenon generate | occur | produces and the temperature of a solar cell element rises, the temperature of a filler will also rise in connection with this. When the outside air temperature decreases, the temperature of the solar cell module, that is, the temperature of the solar cell element and the filler decreases, but the outside temperature gradually decreases, so the filler whose temperature has increased due to the occurrence of the hot spot phenomenon is gradually cooled. That is, it is gradually cooled. When a polymer resin obtained by polymerizing a silane compound with the above-described resin is used as a filler, crystals slowly grow in the filler when it is slowly cooled, and part of the filler becomes cloudy and the appearance is remarkably increased. Damaged.

  Examples of a method for suppressing the temperature rise of the solar cell module when a hot spot phenomenon occurs include, for example, providing a film with a high thermal emissivity on the back side of the solar cell module or surrounding the solar cell module It has been proposed to provide a ventilation opening in the module frame disposed in the frame (for example, see Patent Document 3). In addition, by incorporating particles that increase the thermal conductivity such as alumina and zirconia in the back side filler, the thermal conductivity inside the solar cell module is improved even when a hot spot phenomenon occurs, and the temperature of the solar cell element is increased. A method for suppressing the rise has been proposed (see, for example, Patent Document 4). If the temperature rise of the solar cell module or the solar cell element can be suppressed, the temperature rise of the filler can be suppressed as a result, and it is considered possible to suppress the cloudiness of the filler.

  However, in the above Patent Documents 3 and 4, it is not sufficient to prevent white turbidity of the filler accompanying the occurrence of the hot spot phenomenon, which is not sufficient. Then, the filler for solar cell modules which disperse | distributed the nucleating agent in the resin for fillers for the purpose of preventing the cloudiness of the filler accompanying generation | occurrence | production of a hot spot phenomenon is proposed (patent document 5). .

Moreover, in a solar cell module, in order to raise electric power generation efficiency, transparency is calculated | required with respect to the transparent front substrate and filler which are located on a solar cell element. Furthermore, in order to enhance the design as a solar cell module, it is transparent to the transparent front substrate and the filler located on the solar cell element in order to express without impairing the color of the solar cell element itself. Is required.
Japanese Examined Patent Publication No. 62-14111 JP 2004-214641 A JP-A-6-181333 JP 2004-327630 A JP 2006-245503 A

  However, as described above, as a conventional filler, ethylene-vinyl acetate copolymer resin is the center, and a transparent filler using a copolymer resin obtained by polymerizing a silane compound with a resin having good adhesiveness. At present, there are not many proposals for improving the sexiness. Further, in Patent Document 5, although it is sufficient to prevent white turbidity of the filler due to the occurrence of the hot spot phenomenon, more excellent adhesion and transparency are required today.

  Accordingly, an object of the present invention is to provide a solar cell module filler sheet that can suppress white turbidity of the resin for the filler even when the temperature changes due to a hot spot phenomenon or the like, and is excellent in adhesiveness and transparency. It is in providing the solar cell module using this.

  As a result of intensive studies to solve the above problems, the present inventors have found that an intermediate layer containing a transparent resin for intermediate layer and a nucleating agent dispersed in the transparent resin for intermediate layer, and an adhesive sandwiching the intermediate layer It has been found that the above problem can be solved by using a filler sheet for a solar cell module having a layer, and the present invention has been completed.

  That is, the solar cell module filler sheet according to the present invention includes an intermediate layer containing a transparent resin for an intermediate layer and a nucleating agent dispersed in the transparent resin for the intermediate layer, and the intermediate layer sandwiched between the adhesive layers. And an adhesive layer containing a silane-modified transparent resin as a transparent resin.

  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, even when there is a temperature change due to a hot spot phenomenon or the like, it is possible to suppress the white turbidity of the resin for filler, and to use the filler sheet for solar cell module excellent in adhesion and transparency, and the same A solar cell module can be provided.

  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 an intermediate layer 1 containing a transparent resin for an intermediate layer and a nucleating agent dispersed in the transparent resin for the intermediate layer, and the intermediate layer described above. It has an adhesive layer 2 that sandwiches the layer 1 and has a transparent resin for the adhesive layer.

  According to this invention, it has the intermediate | middle layer 1 containing the transparent resin for intermediate | middle layers and a nucleating agent, the said intermediate | middle layer 1, the adhesive layer 2 containing the transparent resin for adhesive layers, and the said By using the silane-modified transparent resin as the adhesive layer transparent resin, the solar cell module filler sheet 3 can be made excellent in transparency and adhesiveness. Therefore, when used in a solar cell module, it can be laminated with sufficient adhesion strength with the back surface protection sheet, the solar cell element, and the transparent electrode substrate that constitute the solar cell module. Since it can transmit light efficiently, it can be set as the solar cell module which has the outstanding photoelectric conversion efficiency. Further, since the adhesive layer 2 does not contain the nucleating agent, the alkoxysilyl group contained in the adhesive layer transmitting resin contained in the adhesive layer 2 is prevented from being hydrolyzed and further condensed to a siloxane group. And excellent adhesiveness can be maintained for a long time.

  The intermediate layer 1 used in the present invention contains an intermediate layer transparent resin and a nucleating agent, and when used in a solar cell module, light transmitted through the transparent electrode substrate efficiently reaches the solar cell element. There is no particular limitation as long as it is possible.

  The transparent resin for the intermediate layer contained in the intermediate layer 1 used in the present invention is a transparent resin that does not react with the nucleating agent described later and can adhere to the adhesive layer 2 described later with sufficient strength. There is no particular limitation.

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

  Furthermore, in this invention, it is preferable that the said transparent resin for intermediate | middle layers and the transparent resin for adhesive layers 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 intermediate layer 1 and the adhesive layer 2 can be improved. Here, the transparent resin for the intermediate layer and the transparent resin for the adhesive layer are the same type of resin, that the transparent resin for the intermediate layer and the transparent resin for the adhesive layer have the same type of monomer. It means a resin having a polymerized main chain, and does not require the same molecular weight, density, presence / absence of crosslinking, etc.

  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 ethylene-unsaturated carboxylic acid copolymer are sodium. An ionomer intermolecularly bonded with a metal salt such as zinc 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, transparency, and the like.

  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 to 130 degreeC. It is because it is excellent in moldability at the time of manufacture of the solar cell module using the filler sheet for solar cell module. 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 filler sheet for solar cell module of the present invention is excellent.

  The nucleating agent contained in the intermediate layer 1 used in the present invention increases the transparency of the solar cell module filler sheet and serves to form many small crystals. Examples of such nucleating agents include sorbitol nucleating agents, carboxylic acid nucleating agents, and organic phosphate nucleating agents.

  Examples of the sorbitol-based nucleating agent include dibenzylidene sorbitol or derivatives thereof. Specifically, 1, 3, 2, 4-di (meryl benzylidene) sorbitol, 1, 3-chlorobenzylidene-2, 4-methylbenzylidenesorbitol, 1,3,2,4-dibenzylidenesorbitol, 1,3,2,4-di (p-methylbenzylidene) sorbitol, 1,3,2,4-di (p-ethylbenzylidene) Sorbitol, 1,3: 2,4-bis-O-dimethylbenzylidene-D-sorbitol and the like can be used.

  Examples of the carboxylic acid-based nucleating agent include aliphatic carboxylic acids, aliphatic dicarboxylic acids, aromatic carboxylic acids or metal salts of aromatic dicarboxylic acids, or metal salts of alkyl nucleus-substituted derivatives thereof. For example, sodium salt, calcium salt, or aluminum salt of stearic acid, adipic acid, or sebacic acid, or sodium salt of benzoic acid or aluminum salt of para-tert-butyl-benzoic acid can be used.

  Examples of the organophosphate nucleating agent include bis (2,4,8,10-tetra-tert-butyl-6-hydroxy-12H-dibenzo [d, f] [1,3,2] dioxaphos. Syn-6-oxide) aluminum hydroxide salt and the like.

  Moreover, as said nucleating agent, a zeolite, a silica, a talc, a hydrotalcite etc. can also be used, for example.

  Furthermore, these nucleating agents can be used alone or as a mixture.

  Among the nucleating agents, a sorbitol-based nucleating agent is preferably used in the present invention. Furthermore, among the sorbitol nucleating agents, 1,3: 2,4-bis-O-dimethylbenzylidene-D-sorbitol is preferable.

  Moreover, in this invention, it is preferable that the said nucleating agent is contained within the range of 0.005 mass%-3 mass%. If the content of the nucleating agent is too low, the effect of improving the transparency of the solar cell module filler sheet may not be sufficiently obtained. On the other hand, if the content of the nucleating agent is too high, The dispersibility of the product may deteriorate or may be economically disadvantageous. Furthermore, if the content of the nucleating agent is too large, the infrared transmittance decreases, that is, the heat ray absorbability may decrease and the heat absorption may increase, and the temperature inside the solar cell module may easily increase. is there.

  The intermediate layer 2 used in the present invention is not particularly limited as long as it has the above-described intermediate layer transparent resin and nucleating agent, and may include a silane-modified transparent resin and other additives. Good. As said other additive, a light stabilizer, a ultraviolet absorber, or a heat stabilizer can be mentioned.

  As said light stabilizer, the active seed | species of the photodegradation start in the said transparent resin for intermediate | middle layers is captured, and photooxidation is prevented. Specifically, one or a combination of two or more selected from hindered amine compounds, hindered piperidine compounds, and the like 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 intermediate layer are excited. Is to prevent. Specifically, benzophenone-based, benzotriazole-based, salicylate-based, acrylonitrile-based, metal complex-based, hindered amine-based, ultrafine titanium oxide (particle diameter: 0.01 μm 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 μm 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 phosphorous acid. Acid, tetrakis (2,4-di-tert-butylphenyl) [1,1-biphenyl] -4,4'-diylbisphosphonite, and bis (2,4-di-tert-butylphenyl) pentaerythritol Phosphorus heat stabilizers such as diphosphite; and lactone heat stabilizers such as a reaction product of 8-hydroxy-5,7-di-tert-butyl-furan-2-one and o-xylene. it can. 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 mass% to 5 mass. % Is preferable.

  The thickness of the intermediate 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 within the range of 100 μm to 1000 μm. It is preferable that the thickness is 300 μm to 600 μm.

  The adhesive layer 2 used in the present invention contains a transparent resin for an adhesive layer, which is a silane-modified transparent resin, and does not contain a nucleating agent such as sorbitol. By preventing the adhesive layer 2 from containing the nucleating agent, the water absorbed by the nucleating agent can suppress hydrolysis and further condensation of the alkoxysilyl group of the adhesive layer 2 to a siloxane group. And excellent adhesion to the transparent electrode substrate, the solar cell element, and the back surface protective sheet can be maintained for a long period of time.

  The adhesive layer 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 intermediate layer transparent resin, The transparent resin for adhesive layer is preferably the same type of resin. The solar cell module filler sheet 3 of the present invention can be produced at low cost, and the adhesiveness between the intermediate layer 1 and the adhesive layer 2 can be improved.

  As the silane-modified transparent resin used as the transparent resin for the adhesive layer 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, for the intermediate layer described above A transparent resin and a monomer constituting the transparent resin can be used.

  Furthermore, in the present invention, it is preferable to use polyethylene among the transparent resins for intermediate layers. 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, the density is preferably in the range of 0.850 g / cm ^{3 to} 0.960 g / cm ³ , particularly in the range of 0.865 g / cm ^{3 to} 0.930 g / cm ^3. Some are preferred. If the density is higher than 0.960 g / cm ³ , the graft polymerization may be insufficient, and the solar cell module filler sheet 3 of the present invention may not be provided with a desired adhesive force, while the density is This is because if it is lower than 0.850 g / cm ^3, 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. In particular, it is preferably within the range of 0.01 to 3 parts by mass. If the content of the ethylenically unsaturated silane compound is less than 0.001 part by mass, the adhesiveness to the transparent electrode substrate, the solar cell element and the back surface protective sheet may be insufficient, whereas the ethylenic content When the content of the unsaturated silane compound is more than 4 parts by mass, the adhesiveness does not change and the cost may increase.

  The melting point of the silane-modified copolymer is preferably 60 ° C 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. Further, the heating temperature in the method for producing the silane-modified copolymer is different depending on the material such as the ethylenically unsaturated silane compound to be used, but is preferably in the range of 150 ° C. to 300 ° C., 180 ° C. It is preferable to be in the range of ˜270 ° 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 mass%-0.1 mass% is contained in the mixture of the said resin for superposition | polymerization. If it is less than 0.001% by mass, radical polymerization between the ethylenically unsaturated silane compound and the polymerization resin may hardly occur.

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

  The additive resin used in the present invention is not particularly limited as long as it can be uniformly mixed with the adhesive layer transparent resin, but the polymerization resin used for the adhesive layer transparent resin is not limited. It is preferable to use the same. 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, and particularly 0.1 to 2000 parts by mass with respect to 100 parts by mass of the adhesive layer transparent resin. Within the range of parts is preferred. If the content of the additive resin is less than 0.01 parts by mass, the cost may be disadvantageous. On the other hand, if the content of the additive resin is more than 9900 parts by mass, It is because the adhesive force of the solar cell module filler sheet 3 of the invention may be insufficient.

  The melting point of the additive resin is preferably 60 ° C 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 adhesive layer 2 used in the present invention include light stabilizers, ultraviolet absorbers, heat stabilizers, and the like, and those similar to the intermediate layer 1 can be used. However, the ultraviolet absorber does not include a metal complex salt, an inorganic ultraviolet absorber 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 adhesive layer 2 may be lowered.

  Moreover, it is preferable that the contact bonding 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 adhesive 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, or the like constitutes all of the adhesive layer 2. The amount is preferably 0.05 parts by mass or less, more preferably in the range of 0 parts by mass to 0.01 parts by mass, and still more preferably 0 parts by mass with respect to 100 parts by mass of the resin.

  The Si (silicon) content in the adhesive layer 2 used in the present invention is preferably in the range of 8 ppm to 3500 ppm, more preferably in the range of 10 ppm to 3000 ppm, and particularly in the range of 50 ppm 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 of the present invention becomes insufficient, and there is a possibility that a solar cell module excellent in adhesive temporal stability cannot be produced. On the other hand, 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 adhesive 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 adhesive layer 2, the solar cell module filler sheet 3 can be easily reused. 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 the gel fraction, 1 g of the solar cell module filler sheet 3 is weighed and placed in an 80 mesh 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 adhesive layer 2 used in the present invention is not particularly limited as long as it does not impair the transparency of the intermediate layer 1 as much as possible when a solar cell module is used, but within the range of 100 μm to 1000 μm. It is preferable that it is 300 micrometers-600 micrometers.

  The thickness of the solar cell module filler sheet 3 of the present invention is not particularly limited as long as the solar cell module can exhibit sufficient transparency, but is 100 μm to 1000 μm. It is preferably within the range, and more preferably 300 μm to 600 μm.

  In the present invention, the ratio of the thickness of the intermediate layer 1 and the adhesive layer 2 (intermediate layer / adhesive layer) is preferably in the range of 99.5 / 0.5 to 50/50, More preferably, it is within the range of 90/10 to 70/30. If the thickness ratio is smaller than the above range, sufficient transparency may not be obtained. On the other hand, if the thickness ratio is larger than the above range, the adhesive layer 2 may be formed uniformly. It can be difficult. The thickness of the adhesive layer 2 is not the sum of the thicknesses of the adhesive layers 2 laminated on both surfaces of the intermediate layer 1, but the thickness per one layer of the adhesive layer 2.

  The method for producing the solar cell module filler sheet 3 of the present invention is not particularly limited as long as the intermediate layer 1 and the adhesive layer 2 can be laminated with good adhesion. For example, the intermediate layer 1 and the adhesive layer 2 can be separately formed by film forming methods such as an extrusion method, a cast molding method, a T-die method, a cutting method, and an inflation method. After forming the film, a method of laminating, or filling each of the materials for the intermediate layer 1 and the adhesive layer 2 by co-extrusion film formation and laminating the intermediate layer 1 and the adhesive layer 2 The method of manufacturing the material sheet 3 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 view 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 of the present invention is characterized by the above.

  In the solar cell module 11 of the present invention, the front filler sheet 15 is preferably the solar cell module filler sheet 3, and the front filler sheet 15 and the back filler sheet 13 are the solar cell module. The filler sheet 3 is preferably used.

  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, since the said solar cell module filler sheet 3 has the intermediate | middle layer 1, and can permeate | transmit the light which permeate | transmitted the transparent front substrate 16 efficiently, it shall have the outstanding photoelectric conversion efficiency. it can. Furthermore, since the adhesive layer 2 does not contain the nucleating agent, the alkoxysilyl group contained in the transparent resin for the adhesive layer contained in the adhesive layer 2 is hydrolyzed and further suppressed from forming siloxane groups due to condensation. And excellent adhesiveness can be maintained for a long time.

  Further, the gel fraction of the solar cell module filler sheet 3 included in the solar cell module 11 of the present invention is preferably 30% or less, more preferably 10% or less, and 0%. Is even more preferred. If it is higher than the above range, for example, it is difficult to reuse the solar cell module filler sheet 3 after forming the solar cell module 11 using the solar cell module filler sheet 3 including the adhesive layer 2. Because it becomes. 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.

As the solar cell element 14 used in the present invention, 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), 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 preferable that it is normally in the range of 12 micrometers-200 micrometers, and it is still more preferable that it is in the range of 25 micrometers-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 μm to 7000 μm, particularly in the range of 25 μm 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 sheet 15, the solar cell element 14, the back filler sheet 13, and the back protective sheet 12 in this order, as a method for 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, after laminating the transparent front substrate 16, the front filler sheet 15, the solar cell element 14, the back filler sheet 13, and the back protective sheet 12 in this order, these are integrated into a vacuum. The lamination method etc. which are attracted | sucked and thermocompression-bonded can be illustrated.

  The lamination temperature when using the above lamination method is usually preferably in the range of 90 ° C to 230 ° C, particularly preferably in the 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.

[Example 1]
(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)
To 85 parts by mass of M-LLDPE, 2.5 parts by mass of a hindered amine light stabilizer, 7.5 parts by mass of a benzophenone ultraviolet absorber, and 5 parts by mass of a phosphorous heat stabilizer are mixed, melted, processed and pelletized. Thus, an additive master batch was prepared.

(Nuclear agent masterbatch)
A nucleating agent master batch prepared by mixing, melting, processing, and pelletizing 5 parts by mass of a sorbitol nucleating agent with respect to 95 parts by mass of M-LLDPE was prepared.

(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 (intermediate layer).

  First, 20 parts by mass of the silane-modified transparent resin, 80 parts by mass of M-LLDPE, and 5 parts by mass of an additive master batch were mixed as a transparent resin for the adhesive layer, and charged into the hopper A of the film molding machine.

  Next, 20 parts by mass of the silane-modified transparent resin, 80 parts by mass of M-LLDPE, 5 parts by mass of the additive master batch, and 1 part by mass of the nucleating agent master batch are mixed as the transparent resin for the intermediate layer, and the film molding machine Into hopper B of

  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 an intermediate layer containing an intermediate layer transparent resin and a nucleating agent, and the first layer and the third layer sandwiching the intermediate layer are adhesive layers having an adhesive layer transparent resin. A solar cell module filler sheet 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, a solar cell element made of polycrystalline silicon, and a filler sheet for the solar cell module having a thickness of 400 μm; And a laminated sheet (back surface protective sheet) composed of 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) in this order. Then, with the solar cell element surface facing upward, it was pressure-bonded at 150 ° C. for 15 minutes with a vacuum laminator for production of the solar cell module to produce a solar cell module.

[Comparative Example 1]
The mixture of 20 parts by mass of the silane-modified transparent resin prepared in Example 1, 80 parts by mass of M-LLDPE, 5 parts by mass of additive masterbatch, and 5 parts by mass of nucleating agent masterbatch is used in Example 1. The film was put into hopper A and hopper B of a film forming machine, and a 400 μm thick sheet was formed under conditions of an extrusion temperature of 230 ° C. and a take-off speed of 3 m / min to obtain a filler sheet for a solar cell module. In addition, said film formation was able to be implemented without trouble. Moreover, the solar cell module was produced by the same method as Example 1.

(Measurement of adhesion)
The solar cell module filler sheet obtained in Example 1 and Comparative Example 1 was stored in an environment of 40 ° C. and RH 90%, and after storage for 3 months, 6 months, 9 months, and 1 year, solar cells. Using a vacuum laminator for module production, the laminate was pressed with a 3 mm thick glass plate at 150 ° C. for 15 minutes, and the adhesion (peel strength) (unit: N / 15 mm) at a width of 15 mm was measured according to JIS Z1707. The measurement results are shown in Table 1.

[Comparative Example 2]
The hopper A and hopper of the film molding machine used in Example 1 were prepared by mixing 20 parts by mass of the silane-modified transparent resin prepared in Example 1, 80 parts by mass of M-LLDPE, and 5 parts by mass of the additive masterbatch. A sheet having a thickness of 400 μm was formed under conditions of an extrusion temperature of 230 ° C. and a take-off speed of 3 m / min to obtain a filler sheet for a solar cell module. In addition, said film formation was able to be implemented without trouble. Moreover, the solar cell module was produced by the same method as Example 1.

[Examples 2 to 5]
The kind of the nucleating agent masterbatch, the silane-modified resin, the additive polyethylene (M-LLDPE), the kind of the additive masterbatch and the amount of addition thereof are the same as in Example 1, and the sorbitol system in the nucleating agent masterbatch. The addition amount of the nucleating agent and the addition amount of the nucleating agent master batch were changed as shown in Table 2 below, and a solar cell module filler was produced in the same manner as in Example 1. Moreover, the content of the nucleating agent in the obtained filler for solar cell modules is shown in Table 2 below. Further, a solar cell module was produced by the same method as in Example 1.

[Characteristic evaluation]
The following tests were conducted on the solar cell module fillers and solar cell modules in Examples 1 to 5 and Comparative Examples 1 and 2. The measurement results of each test are shown in Table 3 below.

(1) Measurement of haze About the filler for solar cell modules, haze (%) was measured with SM color computer (SM-C) by Suga Test Instruments Co., Ltd. Specifically, a solar cell module filler is sandwiched between blue and white float glass having a total light transmittance of 91%, a haze of 0.2%, and a thickness of 3 mm at 150 ° C. with a vacuum laminator for manufacturing a solar cell module. After pressure bonding for 15 minutes, the sample was cooled by being left at room temperature (25 ° C.) to prepare a sample for haze measurement, and the haze was measured for this sample.

(2) Measurement of adhesion As a measurement of adhesion to a transparent front substrate, filling for a solar cell module immediately after the production of the solar cell module and after leaving for 1000 hours in a high-temperature and high-humidity state at a temperature of 85 ° C. and a humidity of 85% The peel strength (N / 15 mm width) at room temperature (25 ° C.) or less between the material layer and the transparent front substrate was measured.

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

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Intermediate | middle layer 2 Adhesion 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 (9)

  An intermediate layer containing an intermediate layer transparent resin and a nucleating agent dispersed in the intermediate layer transparent resin, an adhesive layer sandwiching the intermediate layer and containing a silane-modified transparent resin as a transparent resin for the adhesive layer; And a solar cell module filler sheet.   The solar cell module filler sheet according to claim 1, wherein the intermediate layer transparent resin is a silane-modified transparent resin and / or a non-silane-modified transparent resin.   The filler sheet for a solar cell module according to claim 1 or 2, wherein the intermediate layer contains 0.005 mass% to 3 mass% of the nucleating agent.   The filler sheet for a solar cell module according to any one of claims 1 to 3, wherein the nucleating agent is a sorbitol-based nucleating agent.   The solar cell module filler sheet according to any one of claims 1 to 4, wherein the intermediate layer transparent resin and the adhesive layer transparent resin are the same type of resin.   The silane-modified transparent resin is a silane-modified copolymer obtained by copolymerizing an ethylenically unsaturated silane compound and a polymerization resin, and the polymerization resin is polyethylene. The filler sheet for solar cell modules according to claim 1. 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,
7. The solar cell module according to claim 1, wherein at least one of the front filler sheet and the back filler sheet is a solar cell module filler sheet according to claim 1.   The solar cell module according to claim 7, wherein the front filler sheet is a solar cell module filler sheet according to claim 1.   The solar cell module according to claim 7, wherein the front filler sheet and the back filler sheet are solar cell module filler sheets according to claim 1.

Images