JP5146828B2 - Back surface filler sheet for solar cell module and solar cell module using the same - Google Patents

Description

  The present invention relates to a back surface filler sheet for a solar cell module and a solar cell module using the same, and more specifically, a back surface for a solar cell module that is excellent in design and adhesion and can maintain insulation for a long period of time. The present invention relates to a filler sheet 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. It needs to be protected. 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 uses a lamination method or the like in which a transparent front substrate, a front filler sheet, a solar cell element, a back filler sheet, a back protective sheet, and the like are sequentially laminated, and these are vacuum-sucked and thermocompression bonded. Manufactured. Moreover, as the solar cell module, a white back surface protection sheet formed using a material containing a white pigment as the back surface protection sheet is used. Furthermore, because it is arranged on the roof of a private house and has a very large area, it may be required to have a design that is the same color as the color of the roofing material. The same color back protective sheet is also used. However, a resin containing carbon black is used as such a back surface protection sheet, but the adhesion between the back surface protection sheet layers sometimes deteriorates.

On the other hand, Patent Document 1 discloses a copolymer sheet of α-olefin and an ethylenically unsaturated silane compound, or a modified or condensate thereof, as a filler sheet laminated on the front surface side and the back surface side of a solar cell element, and a light resistance agent. A filler sheet for a solar cell module comprising a resin film made of a resin composition containing one or more selected from the group consisting of a UV absorber, and a heat stabilizer Is disclosed. Therefore, as the back surface filler sheet, it is also conceivable to make a back surface filler sheet with improved design properties by mixing carbon black or the like with the filler and forming a single layer sheet into a black back surface filler sheet.
JP 2004-214641 A (Claims etc.)

  However, as described above, when a black back surface filler sheet is formed by mixing carbon black or the like into the filler and forming a single layer sheet, the black back surface is laminated on the laminated solar cell element surface when the solar cell module is manufactured. There is a possibility that the filler wraps around and interferes with sunlight reception. In addition, since carbon black is included, the insulating property of the filler sheet is lowered, and the possibility of a short circuit of the solar cell itself is increased. Furthermore, the presence of carbon black may impair adhesion to the back surface protection sheet, solar cell element, or surface filler sheet.

  Accordingly, an object of the present invention is to provide a back surface filler sheet for a solar cell module that is excellent in design and adhesion and can maintain insulation properties for a long period of time, and a solar cell module using the same. .

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have a black layer containing a black pigment and a back surface filler sheet for a solar cell module having an adhesive layer sandwiching the black layer. It has been found that the above problems can be solved, and the present invention has been completed.

  That is, the back surface material sheet for a solar cell module of the present invention includes a black layer containing a black layer transparent resin and a black pigment and the black layer, and contains a silane-modified transparent resin as a transparent resin for the adhesive layer. An adhesive layer, the ratio of the thickness of the black layer to the adhesive layer (black layer / adhesive layer) is 90/10 to 50/50, and the black pigment is carbon It is characterized by being black.

  Moreover, the solar cell module of the present invention includes a back surface protection sheet, the back surface material sheet for the solar cell module formed on the back surface protection sheet, and the sun formed on the back surface material sheet for the solar cell module. It has a battery element, a front filler sheet formed on the solar cell element, and a transparent front substrate formed on the front filler sheet.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in design property and adhesiveness, and can provide the solar cell module using the back surface material sheet for solar cell modules which can maintain insulation for a long period of time.

  Hereinafter, the back surface 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 a back surface filler sheet for a solar cell module of the present invention. As illustrated in FIG. 1, a back surface filler sheet 3 for a solar cell module according to the present invention includes a black layer 1 having a black layer transparent resin and a black pigment, and the black layer 1 sandwiched between the transparent resin for an adhesive layer. It has the adhesive layer 2 which has.

  According to the present invention, the black layer 1 having a transparent resin for black layer and a black pigment, the adhesive layer 2 having the transparent resin for adhesive layer sandwiched between the black layer 1 and the adhesive layer are provided. When the transparent resin is a silane-modified transparent resin, the back surface filler sheet 3 for a solar cell module can be made excellent in adhesiveness and insulation. Therefore, when used in a solar cell module, it can be laminated with sufficient adhesion strength with the back surface protection sheet and the solar cell element constituting the solar cell module, and has excellent insulating properties for a long time. Therefore, it can be set as the solar cell module which has the outstanding photoelectric conversion efficiency. Furthermore, it can have designability by making it the same color as the color of a solar cell element or a roofing material.

  The black layer 1 used in the present invention has a black layer transparent resin and a black pigment, and is not particularly limited as long as it is black in appearance when used in a solar cell module.

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

  In the present invention, as the black layer transparent resin, 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. 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 black layers and the transparent resin for contact bonding layers mentioned later are the same kind of resin. Thereby, the back surface material sheet 3 for solar cell modules of this invention can be produced at low cost, and the adhesiveness of the said black layer 1 and the said contact bonding layer 2 can be made excellent. . Here, “the transparent resin for the black layer and the transparent resin for the adhesive layer are the same kind of resin” means that the black layer transparent resin and the adhesive layer transparent resin are polymerized with the same type of monomer. It means a resin having a main chain and does not require the same molecular weight, density, presence / absence of crosslinking, etc. In addition, since the said back surface material sheet 3 for solar cell modules is arrange | positioned between a solar cell element and a back surface protection sheet, this resin does not need to have high transparency.

  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 A copolymer obtained by copolymerizing one or more of α-olefins such as octene, 1-nonene, and 1-decene, and other unsaturated monomers 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, 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.

  The melting point of the non-silane-modified transparent resin is preferably 60 ° C to 130 ° C. It is because the moldability is excellent during the production of the solar cell module using the back surface filler sheet 3 for the 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.

  Further, 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, particularly 1 g / 10 min to 8 g / 10 min. Some are preferred. It is because it is excellent in the moldability of the back surface filler sheet 3 for solar cell modules of the present invention.

  The black pigment contained in the black layer 1 used in the present invention can be uniformly dispersed in the above-described transparent resin for the black layer, and when the back surface filler sheet 3 for solar cell modules is used for a solar cell module. If the appearance is black, it is not particularly limited.

  The black pigment is preferably carbon black, and only one of gas black, oil furnace black, anthracene black, acetylene black, channel black, oil smoke, pine smoke, animal black, and vegetable black is used alone. You may use, and may use it in combination of 2 or more types. In the present invention, furnace black and acetylene black can be more preferably used. By using carbon black as the black pigment, the black layer 1 having a sufficient black density can be formed with a small addition amount, and thus the back surface filler sheet 3 for the solar cell module can be produced at low cost. .

  The content of the black pigment used in the present invention is not particularly limited as long as it can have the same black density as that of the solar cell element or the roofing material. % To 20% by mass is preferable, and 0.1% to 10% by mass is more preferable. When the blending amount of the black pigment is in the above range, it is more preferable to have the same color as the color of the solar cell element or the roofing material while maintaining the adhesiveness with the adhesive layer 2 and the like, and to have more design. .

  The black layer 1 used in the present invention may contain other additives in addition to the above-described transparent resin for black layer and black pigment. 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 black 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 in the molecule, and the active species that initiate photodegradation in the transparent resin for the black layer is excited. Is to prevent. Specifically, benzophenone-based, benzotriazole-based, salicylate-based, acrylonitrile-based, metal complex-based, hindered amine-based, and 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 and the like, but is 0.01% by mass to 5% in the back surface filler sheet 3 for solar cell modules. Within the range of mass% is preferable.

  The thickness of the black layer 1 used in the present invention is not particularly limited as long as it can show sufficient strength and the like when it is made into a solar cell module, but within the range of 20 μm to 1000 μm. It is preferable that the thickness is 50 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 black pigment such as carbon black. When the adhesive layer 2 does not contain the black pigment, excellent adhesion to the solar cell element and the back surface protective sheet can be maintained for a long period of time, and excellent insulating properties 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 black layer transparent resin, The transparent resin for adhesive layer is preferably the same type of resin. The back surface filler sheet 3 for a solar cell module of the present invention can be produced at low cost, and the adhesion between the black layer 1 and the adhesive layer 2 can be further improved.

  In the present invention, as the silane-modified transparent resin used as the adhesive layer transparent resin, 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. be able to.

  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 that contributes to the adhesive force is increased, and thus the adhesive force of the solar cell module back surface 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 black layer described above The same resin as the transparent resin and the monomer constituting it can be used.

  Furthermore, in this invention, it is preferable to use polyethylene among the said transparent resins for black 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. Is preferred. If the density is higher than the above range, the graft polymerization may be insufficient, and a desired adhesive force may not be imparted to the back surface filler sheet 3 for the solar cell module of the present invention. If it is too low, the mechanical strength of the back surface filler sheet 3 for solar cell modules 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.

  In the silane-modified copolymer used in the present invention, the content of the ethylenically unsaturated silane compound 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 a 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 between the solar cell element and the back surface protective sheet may be insufficient. When there is more content 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 ° C to 110 ° C. It is because the moldability is excellent during the production of the solar cell module using the back surface filler sheet 3 for the solar cell module. 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. It is because the moldability of the back surface filler sheet 3 for a solar cell module 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. More preferably, it is 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-trimethylhexainoyl peroxide, octanoyl peroxide, benzoyl peroxide, o-methylbenzoyl peroxide, 2,4-dichlorobenzoyl peroxide Oxides; t-butyl peroxyacetate, t-butyl Okishi-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 transparent resin for an adhesive layer and does not contain a black pigment. 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, 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 is preferable. 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 back surface filler material sheet 3 for solar cell modules of the invention may be insufficient.

  Moreover, it is preferable that melting | fusing point of the said resin for addition is 80 to 130 degreeC. It is because the moldability is excellent during the production of the solar cell module using the back surface filler sheet 3 for the solar cell module.

  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, particularly preferably 1 g / 10 min to 8 g / 10 min. . It is because it is excellent in the moldability of the back surface filler sheet 3 for solar cell modules of the present 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 the same ones as the black layer 1 can be used. 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 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. 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. If the amount of Si is less than the above range, the adhesive strength of the back surface filler sheet 3 for solar cell modules of the present invention becomes insufficient, and a solar cell module excellent in stability with time of adhesion 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%. If it is 30% or less, for example, after the solar cell module is formed using the back surface filler sheet 3 for solar cell module including the adhesive layer 2, the back surface material sheet 3 for solar cell module is reused. This is because it becomes easy. On the other hand, when the gel fraction is higher than the above range, the workability during the production of the solar cell module may be lowered, or the adhesion strength between the solar cell element and the back surface protective sheet may be insufficient.

  As a method for measuring such a gel fraction, the back surface filler sheet 3 for solar cell modules is peeled and separated into a white layer and an adhesive layer 2, and 1 g of the adhesive layer 2 is then weighed, and an 80-mesh wire mesh is obtained. put into a 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 can exhibit sufficient adhesiveness and the like when it is a solar cell module, but it is within the range of 5 μm to 1000 μm. It is preferable that it is 20 micrometers-600 micrometers.

  Although it will not specifically limit as thickness of the back surface material sheet 3 for solar cell modules of this invention, if it can show sufficient intensity | strength etc. when it is set as a solar cell module, 20 micrometers- It is preferably in the range of 1000 μm, more preferably 100 μm to 600 μm.

  In the present invention, the thickness ratio between the black layer 1 and the adhesive layer 2 (black layer / adhesive layer) is preferably in the range of 95/5 to 5/95, and 90/10. More preferably, it is in the range of ˜50 / 50. If the thickness ratio is smaller than the above range, the designability may not be sufficiently expressed. On the other hand, if the thickness ratio is larger than the above range, the adhesive layer 2 is uniformly formed. And the insulation may be reduced. 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 black layer 1, but the thickness per layer of the adhesive layer 2.

  The method for producing the back surface filler sheet 3 for the solar cell module of the present invention is not particularly limited as long as the black layer 1 and the adhesive layer 2 can be laminated with good adhesion. For example, the black layer 1 and the adhesive layer 2 are individually 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 the film is formed, the method of laminating, or the back surface for a solar cell module in which the respective materials of the black layer 1 and the adhesive layer 2 are formed by multilayer coextrusion and the white layer and the adhesive layer 2 are laminated. The method of manufacturing the filler 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 has a back surface protective sheet 12 and a back surface filler for the solar cell module of the present invention having a black layer 1 and an adhesive layer 2 sandwiching the black layer 1 formed on the back surface protective sheet 12. Sheet 13, solar cell element 14 formed on solar cell module back surface filler sheet 13, front surface filler sheet 15 formed on solar cell element 14, and front surface filler sheet 15. And a transparent front substrate 16.

  According to the present invention, by using the above-described back surface filler sheet 13 for the solar cell module of the present invention, the back surface protection sheet 12 and the solar cell element 14 can be stably laminated with sufficient adhesion strength. Can do. Moreover, since the said back surface filler sheet 13 for solar cell modules has the black layer 1, and can reflect the light which permeate | transmitted the solar cell element 14, it shall have the outstanding photoelectric conversion efficiency. Can do. Furthermore, it can have designability by making it the same color as the color of the solar cell element 14 or the roofing material.

  Moreover, the gel fraction of the contact bonding layer 2 of the back surface material sheet 13 for solar cell modules which the solar cell module 11 of this invention has, ie, the back surface material sheet 13 for solar cell modules after forming the said solar cell module. The gel fraction of the adhesive layer 2 is preferably 30% or less, more preferably 10% or less, and even more preferably 0%. When higher than the above range, for example, after the solar cell module 11 is formed using the solar cell module back surface filler sheet 13 including the adhesive layer 2, the solar cell module back surface filler sheet 13 is reused. May be difficult. Moreover, the adhesion strength between the solar cell element 14 and the back surface protective sheet 12 may be insufficient.

As the solar cell element 14 used in the present invention, a general solar cell element 14 can be used. Specifically, a crystalline silicon solar cell element such as a single crystal silicon type solar cell element or a polycrystalline silicon type solar cell element, an amorphous silicon solar electronic element composed of a single junction type or a 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, the insulating resin film is preferably used in the present invention.

  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 form 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 it is usually preferably in the range of 12 μm to 7000 μm, particularly in the range of 25 μm to 4000 μm. Is preferred.

  The front filler sheet 15 used in the present invention is not particularly limited as long as it has transparency to sunlight and exhibits adhesiveness to the transparent front substrate 16 and the solar cell element 14. Specific examples of the material constituting the front filler sheet 15 include fluorine resin, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid, or methacrylic acid copolymer, polyethylene resin, polypropylene. Resin, polyolefin resin such as polyethylene or polypropylene, acid-modified polyolefin resin modified with unsaturated carboxylic acid such as acrylic acid, itaconic acid, maleic acid, fumaric acid, polyvinyl butyral resin, silicone resin, epoxy resin, ( A mixture of one or more resins such as a (meth) acrylic resin can be used. In the present invention, among the above resins, it is preferable to use a fluorine resin, a silicone resin, or an ethylene-vinyl acetate resin, and it is particularly preferable to use a silicone resin.

  The silicone resin is not particularly limited as long as it is a resin having an alkoxysilyl group, but a thermoplastic silane-modified resin is particularly preferable. Further, in the present invention, as the thermoplastic silane-modified resin, the same resin as the silane-modified transparent resin used as the adhesive layer transparent resin in the adhesive layer 2 of the solar cell module back surface filler sheet 13 of the present invention described above. Is preferably used. Thus, the production cost can be reduced by unifying the thermoplastic silane-modified resin used for the front filler sheet 15 and the silane-modified transparent resin used for the adhesive layer 2.

  In the present invention, the front filler sheet 15 may contain an additive in addition to the resin. Examples of such additives include cross-linking materials, thermal antioxidants, light stabilizers, ultraviolet absorbers, and photo-antioxidants.

  The thickness of the front filler sheet 15 used in the present invention is not particularly limited, but is usually in the range of 200 μm to 1000 μm, preferably in the range of 350 μm to 600 μm.

  Furthermore, the front filler sheet 15 used in the present invention preferably has a total light transmittance in the range of 70% to 100%, more preferably in the range of 80% to 100%. It is preferable to be within the range of 90% to 100%. It is because it can prevent that the power generation efficiency of a solar cell module is impaired by the said total light transmittance being in the said range. In addition, the said total light transmittance can be measured by a normal method, for example, can be measured with a color computer.

  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, the transparent front substrate 16, the front filler sheet 15, the solar cell element 14, the back filler sheet 13 for the solar cell module, and the back protective sheet 12 are laminated in this order, and then these are thermocompression bonded. Is not particularly limited as long as it is a method capable of closely adhering each of the above components, and a generally known method 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 for the solar cell module, and the back protective sheet 12 in this order, The lamination method etc. which vacuum-suck and heat-pressure-bond can be illustrated as one.

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

(Black pigment master batch)
A black pigment master batch was prepared by mixing 20 parts by mass of acetylene black as a black pigment with 80 parts by mass of M-LLDPE, melting, processing and pelletizing.

(Preparation of backside sheet for solar cell module)
In the production of the back surface filler sheet for the solar cell module, a φ25 mm extruder capable of two-layer / three-layer structure and a film molding machine having a 300-mm wide T-die 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, 95 parts by mass of the M-LLDPE, 5 parts by mass of the additive master batch, and 5 parts by mass of the black pigment master batch were mixed as a transparent resin for the black layer, and charged into the hopper B of the film molding machine.

  Next, using the film molding machine, a sheet having a thickness of 400 μm at an extrusion temperature of 230 ° C., a take-off speed of 3 m / min, a thickness of the first and third layers of 100 μm, and a thickness of the second layer of 200 μm, respectively. The second layer is a black layer containing a black layer transparent resin and a black pigment, and the first layer and the third layer sandwiching the black layer have an adhesive layer transparent resin. The back surface filler sheet for solar cell modules which is a layer was obtained. In addition, said film formation was able to be implemented without trouble.

(Surface filler sheet)
As an adhesive layer transparent resin, 20 parts by mass of the silane-modified transparent resin, 80 parts by mass of M-LLDPE, and 5 parts by mass of the additive master batch are mixed, put into the hopper A of the film molding machine, and extruded. A surface filler sheet with a thickness of 400 μm was obtained at a temperature of 230 ° C. and a take-up speed of 3 m / min.

(Production of solar cell module)
A glass plate (transparent front substrate) having a thickness of 3 mm, the surface filler sheet having a thickness of 400 μm, a solar cell element made of polycrystalline silicon, a back filler for the solar cell module having a thickness of 400 μm, and a thickness A 38 μm polyvinyl fluoride resin sheet (PVF), a 30 μm thick polyethylene terephthalate sheet and a 38 μm thick polyvinyl fluoride resin sheet (PVF) laminated sheet (back surface protection sheet) are laminated in this order, The solar cell module was produced by pressing the battery element surface upward at 150 ° C. for 15 minutes with a vacuum laminator for manufacturing the solar cell module.

[Comparative Example 1]
A 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 an additive masterbatch, and 5 parts by mass of a black pigment masterbatch is used in Example 1. The film was put into hopper A and hopper B of the former film forming machine, and a sheet having a thickness of 400 μm was formed under the conditions of an extrusion temperature of 230 ° C. and a take-off speed of 3 m / min. A back filler sheet was obtained. 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.

[Example 2, Reference Example and Comparative Example 2]
The kind of black pigment master batch, the silane-modified resin, the additive polyethylene (M-LLDPE), the kind of additive master batch and the amount of addition thereof are the same as in Example 1, and the layer ratio of the black layer to the adhesive layer Was changed as shown in Table 1 below, and a solar cell module filler was produced in the same manner as in Example 1. Moreover, the solar cell module was produced by the same method as Example 1.

[Evaluation of characteristics]
The following tests were conducted on the filler for solar cell modules and the solar cell modules in Examples 1 and 2, Reference Example and Comparative Examples 1 and 2. The measurement results of each test are shown in Table 2 below.

(Black filler wraps around the cell (wraps around the cell))
It was visually confirmed whether or not a black filler had wrapped around the cell surface of the produced solar cell module. The case where there was no wraparound was indicated by ○, and the case where there was wraparound was indicated by ×.

(Measurement of adhesion)
As a measurement of adhesion to the transparent front substrate, the solar cell module filler layer and the transparent front substrate were measured immediately after production and after being left for 1000 hours in a hot and humid state at a temperature of 85 ° C. and a humidity of 85%. The peel strength (N / 15 mm width) at room temperature (25 ° C.) was measured.

(Measurement of insulation)
The volume resistance value of the produced back surface filler for solar cell modules was measured.

  From Table 2, the comparative example 1 was inferior to adhesiveness, and could not maintain insulation for a long period of time. Moreover, since the external appearance was not black, the comparative example 2 was inferior to the designability. On the other hand, Examples 1 and 2 and the reference example were excellent in designability and adhesiveness, and were able to maintain insulation for a long time.

It is the schematic which shows an example of the back surface 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 Black layer 2 Adhesive layers 3, 13 Back surface filler sheet 11 for solar cell modules Solar cell module 12 Back surface protection sheet 14 Solar cell element 15 Front surface filler sheet 16 Transparent front substrate

Claims (6)

A black layer containing a transparent resin for a black layer and a black pigment; and an adhesive layer sandwiching the black layer and containing a silane-modified transparent resin as a transparent resin for an adhesive layer, the black layer and the adhesive layer (Black layer / adhesive layer) is 90/10 to 50/50, and the black pigment is carbon black. Sheet.   The solar cell module filler sheet according to claim 1, wherein the black layer transparent resin is a silane-modified transparent resin and / or a non-silane-modified transparent resin.   The back surface filler sheet for a solar cell module according to claim 1 or 2, wherein the transparent resin for a black layer and the transparent resin for an adhesive layer 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 back surface filler sheet for solar cell modules according to claim 1.   The back filler sheet for a solar cell module according to any one of claims 1 to 4, wherein a blending amount of the black pigment in the black layer is 0.01% by mass to 20% by mass. A back protection sheet,
The back surface filler sheet for a solar cell module according to any one of claims 1 to 5 , formed on the back surface protection sheet,
A solar cell element formed on the back surface filler sheet for the solar cell module;
A front filler sheet formed on the solar cell element;
A solar cell module comprising: a transparent front substrate formed on the front filler sheet.

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