JP2010258427A - Adhesive sheet for solar cell and method of producing the same, and solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive sheet for a solar cell, wherein a film is stably and uniformly formed without staying or solidifying an ethylene-based copolymer within a T die at film forming. <P>SOLUTION: The adhesive sheet A for the solar cell are laminated and integrated two or more sheet layers 1, 1, ..., containing a thermoplastic resin, and includes: a peroxide sheet layer 1a which contains organic peroxide and does not contain a crosslinking assistant; and a crosslinking assistant sheet layer 1b which does not contain peroxide and contains a crosslinking assistant. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an adhesive sheet for a solar cell used when producing a solar cell module, a method for manufacturing the same, and a solar cell module.

  A solar cell module consisting of a silicon or selenium semiconductor wafer has a reduced pressure on a laminate obtained by overlaying a transparent protective material on the upper surface of a solar cell element with a solar cell adhesive sheet laminated on both sides and a back surface protective material on the lower surface. It is manufactured by heating while degassing below and stacking and integrating the protective material on the upper and lower surfaces of the solar cell element via an adhesive sheet. In addition, in a solar battery module including a structure in which solar cells made of silicon, a compound semiconductor, or the like are laminated on a substrate in the form of a thin film, a similar adhesive sheet for solar cells is used to seal the solar cells. It has been.

  As an adhesive sheet for a solar cell used in such a solar cell module, for example, in Patent Document 1, a protective sheet for a solar cell module made of an ethylene copolymer containing an organic peroxide is used as an organic peroxide. A dialkyl peroxide (A) and at least one peroxide (B) selected from the group consisting of alkyl peroxyesters and peroxyketals, wherein the weight ratio of (A) / (B) is 10/90 to 90 A protective sheet for a solar cell module, which is characterized by using a blended material at a ratio of / 10 has been proposed. As a method for forming this protective sheet for a solar cell module, a resin composition comprising an ethylene copolymer and an organic peroxide is melt-kneaded at 80 to 130 ° C. with an extruder, and is disposed at the tip of the extruder. A method of forming an extrusion film from an installed T die is disclosed.

  Here, when film-forming the said protection sheet for solar cell modules using T die, when the temperature in T die is 80-110 degreeC, the melt viscosity of resin becomes high and the resin composition becomes T It tends to stay in the die. Then, since the contact time between the resin composition developed in a sheet form in the T die and the inner surface of the T die having a high temperature becomes longer, the organic peroxide in the resin composition in contact with the inner surface of the T die is reduced. It decomposes and the crosslinking of the resin proceeds. Therefore, the melt viscosity of the resin composition is further increased, and the resin composition stays in the T-die so that a sheet having a uniform thickness cannot be formed. In addition, since the resin is cross-linked in this way and the melt viscosity of the resin composition is increased, the residence time of the resin composition in the T-die is further increased, so that the cross-linking of the resin further proceeds, There was also a situation in which the resin solidified in the T-die and the sheet could not be extruded.

  On the other hand, when the solar cell module protective sheet is formed, if the temperature in the T die is 110 to 130 ° C., the temperature on the inner surface of the T die is high, so that the sheet is developed in the T die. The heated resin composition is heated on the inner surface of the T die, the organic peroxide is decomposed, and the crosslinking of the resin proceeds. Therefore, the melt viscosity of the resin composition is further increased, and the resin composition stays in the T-die, resulting in a problem that a sheet having a uniform thickness cannot be obtained. In addition, if the resin composition stays in the T die, the contact time between the resin composition developed in the form of a sheet and the inner surface of the T die becomes longer, and the crosslinking of the resin further proceeds. There was also a situation in which the sheet could not be extruded due to solidification.

  Patent Document 2 discloses an adhesive sheet for a solar cell in which three or more sheet layers made of an ethylene copolymer and an organic peroxide are laminated and integrated, and the sheet layer is the The outer sheet layer contains 0.3 to 3 parts by weight of an organic peroxide and 0.01 to 2 parts by weight of a scorch inhibitor with respect to 100 parts by weight of the ethylene copolymer. A solar cell adhesive sheet is disclosed in which the sum of the thicknesses of the sheet layers is 20% or less of the thickness of the entire sheet.

  However, the outermost sheet layers on both sides of the solar cell adhesive sheet contain a scorch preventing agent, and this scorch preventing agent has a problem that the solar cell adhesive sheet is colored. .

JP 11-26791 A JP 2007-299917 A

  The present invention relates to an adhesive sheet for a solar cell, a method for producing the solar cell, and a solar cell that can stably form a film with a uniform thickness without causing a thermoplastic resin to stay or solidify in a T-die during film formation. Provide modules.

  The solar cell adhesive sheet of the present invention is a solar cell adhesive sheet in which two or more sheet layers containing a thermoplastic resin are laminated and integrated, and contains an organic peroxide and a crosslinking aid. It has a peroxide sheet layer that does not contain, and a crosslinking aid sheet layer that does not contain an organic peroxide and contains a crosslinking aid.

  In the solar cell adhesive sheet, the peroxide sheet layer and the crosslinking aid sheet layer are laminated and integrated adjacent to each other.

  In the solar cell adhesive sheet, characterized in that a non-crosslinking agent-containing sheet layer containing no organic peroxide and a crosslinking aid is interposed between the peroxide sheet layer and the crosslinking aid sheet layer. To do.

 In the upper solar cell adhesive sheet, the outermost sheet layers on both sides are cross-linking agent-free sheet layers that do not contain an organic peroxide and a cross-linking aid.

  In the solar cell adhesive sheet, the sheet layer has a thickness of 300 μm or less. In the solar cell adhesive sheet, the thermoplastic resin constituting the peroxide sheet layer is a polyethylene resin or ethylene-propylene rubber.

  In the solar cell module of the present invention, the solar cell element is sealed and integrated from above and below by the solar cell adhesive sheet, and the transparent protective material is laminated and integrated on the upper solar cell adhesive sheet. The back surface protective material is laminated and integrated on the lower solar cell adhesive sheet.

  The solar cell module of the present invention has a solar cell formed in a thin film on a transparent substrate, and the solar cell adhesive according to any one of claims 1 to 8 on the solar cell. Sheets are laminated and integrated, solar cells are sealed by the transparent substrate and the solar cell adhesive sheet, and a back surface protective material is laminated and integrated on the solar cell adhesive sheet. Features.

  The solar cell module of the present invention has solar cells formed in a thin film on a substrate, and the solar cell adhesive sheet according to any one of claims 1 to 8 on the solar cells. Is laminated and integrated, solar cells are sealed by the substrate and the adhesive sheet for solar cells, and a transparent protective material is laminated and integrated on the adhesive sheet for solar cells. To do.

  The solar cell adhesive sheet of the present invention is a solar cell adhesive sheet in which two or more sheet layers containing a thermoplastic resin are laminated and integrated, and contains an organic peroxide and a crosslinking aid. Since it has a peroxide sheet layer that does not contain and a crosslinking aid sheet layer that does not contain an organic peroxide and contains a crosslinking aid, at the time of film formation of the adhesive sheet for solar cells, The thermoplastic resin is not excessively cross-linked in the T-die and does not stay or solidify. Therefore, the solar cell adhesive sheet has a uniform thickness, and the solar cell element and the protective material are Through the adhesive sheet for a battery, it can be reliably crimped and integrated as a whole.

  In the solar cell adhesive sheet, when the peroxide sheet layer and the crosslinking aid sheet layer are laminated and integrated adjacent to each other, the peroxide is sealed when the solar cell element is sealed. The organic peroxide contained in the sheet layer and the crosslinking aid contained in the crosslinking aid sheet layer are smoothly mixed so that both the peroxide sheet layer and the crosslinking aid sheet layer have a desired degree of crosslinking. Therefore, the solar cell adhesive sheet has excellent heat resistance, and reliably maintains excellent adhesion over a long period of time even in outdoor use where the temperature is high. Has excellent durability.

  The method for producing a solar cell encapsulating sheet of the present invention has the above-described configuration, and the resin composition for the organic peroxide sheet layer contains an organic peroxide, but is a crosslinking aid. Since the crosslinking property is suppressed, the resin composition for the crosslinking aid sheet layer does not contain an organic peroxide, and thus has no crosslinking property.

  And at the time of film formation of the adhesive sheet A for solar cells, the resin composition for the crosslinking aid sheet layer or the resin composition for the crosslinking agent-free sheet layer that is in direct contact with the inner surface of the T die that is at a high temperature is Since the resin composition for the peroxide sheet layer contains an organic peroxide, the inner surface of the T die is not cross-linked by contact with the T die because it does not have crosslinkability. Since the resin composition for the cross-linking aid sheet layer is interposed, it is not heated excessively and hardly crosslinks in the T-die.

  Therefore, in the method for producing an adhesive sheet for solar cells of the present invention, the resin composition for the peroxide sheet layer and the resin composition for the crosslinking aid sheet layer do not stay or solidify in the T-die. The peroxide sheet layer and the crosslinking aid sheet layer can be smoothly extruded from the T-die to produce the solar cell adhesive sheet A having a uniform thickness.

  Furthermore, in the manufacturing method of the sealing sheet for solar cells of this invention, it bridge | crosslinks between the resin composition for peroxide sheet layers, and the resin composition for crosslinking adjuvant sheet layers in T die. When the resin composition of the non-agent-containing sheet layer is interposed, the organic peroxide in the resin composition for the peroxide sheet layer and the crosslinking aid in the resin composition for the crosslinking aid sheet layer are used. To prevent coexistence with the agent, and more reliably prevent the resin composition for the peroxide sheet layer and the resin composition for the crosslinking aid sheet layer from staying or solidifying in the T-die. Then, the peroxide sheet layer and the crosslinking aid sheet layer can be more smoothly extruded from the T-die to produce the solar cell adhesive sheet A having a more uniform thickness.

It is the longitudinal cross-sectional view which showed the adhesive sheet for solar cells of this invention. It is a longitudinal cross-sectional view of the solar cell module using the adhesive sheet for solar cells of this invention. It is the longitudinal cross-sectional view which showed another example of the adhesive sheet for solar cells of this invention. It is the longitudinal cross-sectional view which showed another example of the adhesive sheet for solar cells of this invention. It is the longitudinal cross-sectional view which showed another example of the solar cell module using the adhesive sheet for solar cells of this invention. It is the longitudinal cross-sectional view which showed another example of the solar cell module using the adhesive sheet for solar cells of this invention.

  An example of the solar cell module of the present invention will be described with reference to the drawings. The adhesive sheet A for solar cells is an adhesive sheet for solar cells in which two or more sheet layers 1, 1... Containing a thermoplastic resin are laminated and integrated, and contains an organic peroxide. It has a peroxide sheet layer 1a that does not contain a crosslinking aid, and a crosslinking aid sheet layer 1b that does not contain an organic peroxide and contains a crosslinking aid.

  First, as shown in FIG. 1, the case where the adhesive sheet A for solar cells is formed by laminating and integrating three sheet layers 1, 1,.

  It does not specifically limit as a thermoplastic resin which comprises the sheet | seat layer 1 of a solar cell module, For example, an ethylene-type copolymer, a polyethylene-type resin, ethylene-propylene rubber, a polypropylene-type resin etc. are mentioned. And as a thermoplastic resin which comprises the peroxide sheet layer mentioned later, a polyethylene-type resin and ethylene-propylene rubber with low crosslinkability are preferable.

  The ethylene-based copolymer used for the sheet layer 1 is a copolymer of ethylene and a copolymerizable monomer other than propylene that can be copolymerized with ethylene, and such a copolymerizable monomer is particularly limited. Examples thereof include vinyl acetate, acrylic acid, acrylic ester, methacrylic acid, methacrylic ester, maleic acid, maleic anhydride, maleic ester and the like, and vinyl acetate is preferable. In addition, the said copolymerizable monomer may be copolymerized with ethylene independently, or 2 or more types may be copolymerized with ethylene.

  If the amount of the copolymerizable monomer contained in the ethylene-based copolymer is small, the resulting solar cell adhesive sheet is insufficient in transparency, and the power generation efficiency of the solar cell element may be reduced. And film formation stability and mechanical strength of the adhesive sheet for solar cells may be insufficient, so that it is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, and 14 to 35% by weight. % Is particularly preferred.

  And, if the melt flow rate of the ethylene-based copolymer is small, the film-forming stability of the adhesive sheet for solar cells may decrease, whereas if it is large, the mechanical strength of the adhesive sheet for solar cells is insufficient. Therefore, 1 to 100 g / 10 min is preferable. The melt flow rate of the ethylene copolymer in the present invention refers to a value measured under conditions of a temperature of 190 ° C. and a load of 2.16 kgf (21.18 N) according to JIS K7210.

  The polyethylene resin is not particularly limited, and for example, low density polyethylene resin, medium density polyethylene resin, high density polyethylene resin, linear low density polyethylene resin, linear medium density polyethylene resin, linear high density polyethylene. Resin, etc., may be used alone or in combination

  The polypropylene resin is not particularly limited, and examples thereof include a propylene homopolymer, a propylene component containing more than 50% by weight, and a copolymer of propylene and another olefin. Two or more of them may be used in combination. Further, the copolymer of propylene and other olefins may be any of a block copolymer, a random copolymer, and a random block copolymer.

  Examples of the olefin copolymerized with propylene include α such as ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene and 1-decene. -Olefin etc. are mentioned.

  Here, the solar cell adhesive sheet A is used by interposing between one or both of the transparent protective material and the back surface protective material and the solar cell element during the production of the solar cell module, and under reduced pressure. After the deaeration treatment, the solar cell element is sealed and integrated by thermocompression bonding under pressure, and the solar cell element and the upper and lower protective materials are bonded. Thermoplastic resins, especially ethylene copolymers, are excellent in transparency and adhesiveness among the transparency, adhesiveness and heat resistance particularly required for adhesive sheets for solar cells. There is a problem that it is low. Therefore, an organic peroxide is contained in the thermoplastic resin constituting the solar cell adhesive sheet A, and the thermoplastic resin is cross-linked by heat applied at the time of manufacturing the solar cell module. Improves heat resistance.

  However, when the thermoplastic resin is excessively crosslinked in the film forming step of the solar cell adhesive sheet A as described later, the thermoplastic resin stays in the T-die and the solar cell adhesive sheet has a uniform thickness. Cannot be obtained, or the thermoplastic resin is solidified in the T-die and the solar cell adhesive sheet cannot be formed.

  Therefore, the solar cell adhesive sheet A of the present invention contains, as a central sheet layer, a peroxide sheet layer 1a that contains an organic peroxide and does not contain a crosslinking aid, on both sides of the peroxide sheet layer 1a. As the outermost sheet layer, cross-linking aid sheet layers 1b and 1b containing no organic peroxide and containing a cross-linking aid are laminated and integrated.

  Thus, the sheet layers 1a and 1b constituting the solar cell adhesive sheet A contain only one of an organic peroxide and a crosslinking aid, and the organic peroxide and the crosslinking aid are It does not coexist.

  That is, since the sheet layer 1a contains an organic peroxide but does not contain a crosslinking aid, the crosslinking property is suppressed, and the crosslinking aid sheet layer 1b contains an organic peroxide. Since it does not contain, it does not have crosslinkability.

  When the solar cell adhesive sheet A is formed, the crosslinking aid sheet layer 1b that is in direct contact with the inner surface of the T die, which is at a high temperature, does not have crosslinkability. There is no cross-linking.

  On the other hand, although the central peroxide sheet layer 1a contains an organic peroxide, it is not in direct contact with the inner surface of the T-die, and the cross-linking aid sheet layer 1b is interposed. Is not heated and hardly crosslinks in the T-die.

  Therefore, when the solar cell adhesive sheet is formed, the sheet layers 1a and 1b do not stay or solidify in the T die, and the sheet layers 1a and 1b are smoothly extruded from the T die to have a uniform thickness. The solar cell adhesive sheet A can be obtained.

  Examples of the organic peroxide used for the sheet layer 1a include dicumyl peroxide (136 ° C), t-butylperoxy-2-ethylhexyl monocarbonate (119 ° C), and t-butylperoxybenzoate (125 ° C). 1,1-di (t-butylperoxy) -2-methylcyclohexane (102 ° C.), 1,1-di (t-hexylperoxy) -3,3,5-trimethylcyclohexane (106 ° C.), 1 , 1-di (t-hexylperoxy) cyclohexane (107 ° C.), 1,1-di (t-butylperoxy) cyclohexane (111 ° C.), 2,2-di (4,4-di (t-butyl) Peroxy) cyclohexyl) propane (114 ° C.), t-hexyl peroxyisopropyl monocarbonate (115 ° C.), t-butyl peroxyisopropyl Pyrmonocarbonate (118 ° C.), t-butyl peroxylaurate (118 ° C.), 2,5-dimethyl-2,5-di (benzoylperoxy) hexane (119 ° C.), t-hexyl peroxybenzoate (119 ° C), t-butylperoxymaleic acid (119 ° C), t-butylperoxy-3,5,5-trimethylhexanoate (119 ° C), t-butylperoxyacetate (121 ° C), 2,2 -Di (t-butylperoxy) butane (122 ° C), n-butyl-4,4-di (t-butylperoxy) valerate (127 ° C), di-t-hexyl peroxide (136 ° C), t -Butylcumyl peroxide (137 ° C), di (2-t-butylperoxyisopropyl) benzene (138 ° C), 2,5-dimethyl-2,5-di ( t-butylperoxy) hexane (138 ° C.), di-t-butyl peroxide (144 ° C.), 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3 (150 ° C.), p-menthane hydroperoxide (151 ° C.) and the like may be mentioned, and these may be used alone or in combination of two or more. The temperature in the parenthesis represents a 1 hour half-life temperature.

  When the amount of the organic peroxide contained in the sheet layer 1a is small, when the solar cell module is produced, the thermoplastic resin is insufficiently crosslinked, and the heat resistance of the solar cell adhesive sheet is insufficient. The durability of the resulting solar cell module is reduced, and if it is large, the sheet layer 1a is cross-linked and stays in the T-die when the solar cell adhesive sheet is formed. It becomes impossible to obtain or the thermoplastic resin is solidified in the T-die and the solar cell adhesive sheet cannot be extruded, so 0.3 to 3 parts by weight with respect to 100 parts by weight of the thermoplastic resin Is preferable, and 0.5 to 1.5 parts by weight is more preferable.

  Examples of the crosslinking aid include polyfunctional monomers having two or more allyl groups, vinyl groups, acryloyl groups or methacryloyl groups, which stabilize polymer radicals to increase crosslinking efficiency and concentrate crosslinking points. Accelerates gel formation. Examples of the polyfunctional monomer include diallyl phthalate, diallyl itaconate, diallyl maleate, triallyl isocyanurate, triallyl cyanurate, triallyl phosphate, divinylbenzene; 1,6-hexanediol di (meth) acrylate (Meth) such as ethylene oxide modified bisphenol A di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ε-caprolactone modified dipentaerythritol Examples thereof include acrylates and (meth) acrylates of alkyl-modified dipentaerythritol, which may be used alone or in combination of two or more.

  If the amount of the crosslinking aid contained in the sheet layer 1b is small, crosslinking of the solar cell adhesive sheet may be insufficient during the production of the solar cell module. Since the degree becomes too high and hard, the solar cell element may be excessively stressed, which may be undesirable for protecting the solar cell element, and is therefore 0.01 to 100 parts by weight with respect to 100 parts by weight of the thermoplastic resin. 1 part by weight is preferred.

  Further, when the thickness of the sheet layers 1a and 1b is large, the organic peroxide contained in the peroxide sheet layer 1a and the crosslinking aid sheet layers 1b and 1b are contained in manufacturing the solar cell module. Is not sufficiently mixed with the cross-linking auxiliary agent, the cross-linking of the entire solar cell adhesive sheet A may be insufficient, and the heat resistance of the solar cell adhesive sheet A may be reduced. Since the thickness of the solar cell adhesive sheet may be uneven, 1 to 300 μm is more preferable.

  In addition, as long as it is in the range which does not impair the physical property of the adhesive sheet A for solar cells, the sheet layers 1a and 1b may prevent oxidation of 2,6-di-t-butyl-4-methylphenol or the like as necessary. You may add additives, such as an ultraviolet-ray absorber, flame retardants, such as an agent, 2-hydroxy-4-methoxy benzophenone.

  Furthermore, a coupling agent may be added to the sheet layers 1a and 1b for the purpose of improving the adhesiveness of the solar cell adhesive sheet A as long as the physical properties of the solar cell adhesive sheet A are not impaired. . As such a coupling agent, a silane coupling agent having one or two or more functional groups selected from the group consisting of an amino group, a glycidyl group, a methacryloxy group and a mercapto group is preferably used. -Aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, etc. May be.

  Next, a method for forming the solar cell adhesive sheet A will be described. The film formation of the adhesive sheet A for solar cells can be performed by a multilayer extrusion apparatus in which two or more extruders are connected to one T die via one feed block, for example, three layers A multi-layer extruder having a minute-extruder is prepared, and a thermoplastic resin and a cross-linking aid for the cross-linking aid sheet layer 1b on both sides are added to the two extruders of this multi-layer extruder and, if necessary, added. While supplying the resin composition containing the additive, the remaining one extruder contains the thermoplastic resin and organic peroxide for the peroxide sheet layer 1a, and the additive added as necessary. Supply the resin composition, melt and knead the resin composition in each extruder, supply to the feed block, cross-linking aid sheet layer 1b from the T-die disposed at the tip of the feed block, peroxidation Material sheet layer 1a and crosslinking aid sheet layer 1b A film can be formed by extruding into a sheet so as to be laminated and integrated in this order, and cooling and solidifying and winding the extruded molten sheet with a cooling roll. When the sheet layers 1b and 1b on both sides are made of the same resin composition, melt kneading is performed with one extruder, and the molten resin composition extruded from the extruder is branched into two and then fed. The film may be supplied to the block.

  In the film-forming process of the adhesive sheet A for solar cells, if the temperature at which the resin composition constituting the sheet layers 1a and 1b is melted and kneaded in the extruder is high, the organic peroxide in the resin composition is decomposed. Since the crosslinking of the thermoplastic resin may proceed, the temperature is preferably 10 ° C. or more lower than the one-hour half-life temperature of the organic peroxide used, and two or more organic peroxides are used. In the case of using, it is preferable that the organic peroxide to be used has a temperature that is 10 ° C. or more lower than the one-hour half-life temperature of the lowest organic peroxide.

  Moreover, you may manufacture the adhesive sheet A for solar cells by laminating | stacking and integrating the film which comprises each sheet layer using general-purpose methods, such as extrusion lamination, other than the said manufacturing method.

  Further, the solar cell adhesive sheet A is preferably embossed on the surface in order to improve the deaeration in the thermocompression bonding step when the solar cell module is manufactured. In addition, as a method of embossing the surface of the adhesive sheet A for solar cells, a known method is used. For example, the adhesive sheet A for solar cells in a molten state immediately after being extruded from a T die is embossed on the surface. The embossing roll on which the pattern is applied and the rubber roll arranged opposite to the embossing roll are supplied, and the embossing roll is pressed against the molten sheet to emboss the surface of the adhesive sheet A for solar cells. The method of giving is mentioned. The once produced solar cell adhesive sheet A may be heated again to a molten state and embossed as described above.

  And as a method of manufacturing a solar cell module using the solar cell adhesive sheet A of the present invention, a transparent protective material 3 such as a glass plate is laminated on the upper surface of the solar cell element 2 via the solar cell adhesive sheet A. At the same time, a laminated body in which the back surface protective material 4 is laminated on the lower surface of the solar cell element 2 via the solar cell adhesive sheet A is produced, and this laminated body is subjected to thermocompression bonding under reduced pressure. Examples of the solar cell element 2 include a solar cell element having a structure using a single crystal or polycrystalline wafer, and a solar cell element in which silicon, a compound semiconductor, or the like is laminated and integrated into a thin film on a substrate. It is done.

  Then, the solar cell adhesive sheets A and 1A laminated on the upper and lower surfaces of the solar cell element are melted to fill the gap between the solar cell elements 2 and 2, and the sheet layers 1a and 1b are mixed together. Then, the organic peroxide contained in the peroxide sheet layer 1a and the crosslinking aid contained in the crosslinking aid sheet layer 1b are mixed, and the entire solar cell adhesive sheet A is organically oxidized. The coexistence of the product and the crosslinking aid provides sufficient crosslinking and imparts excellent heat resistance.

  And the transparent protective material 3 is laminated | stacked and integrated on the upper surface of the solar cell element 2 via the adhesive sheet A for solar cells, and back surface protection is provided on the lower surface of the solar cell element 2 via the adhesive sheet A for solar cells. The solar cell module B can be obtained by stacking and integrating the materials 4 (see FIG. 2).

  In the above, the case where the solar cell adhesive sheet A is formed by laminating and integrating the three sheet layers 1b, 1a, and 1b has been described. However, the solar cell adhesive sheet A has four layers as shown in FIG. The above sheet layers 1, 1... May be laminated and integrated.

  In the case of such an adhesive sheet A for solar cells, the outermost sheet layers on both sides are the crosslinking aid sheet layers 1b and 1b that do not contain an organic peroxide and contain a crosslinking aid, and the crosslinking aids on both sides. It is preferable that at least one of the remaining sheet layers excluding the sheet layers 1b and 1b is a peroxide sheet layer 1a that contains an organic peroxide and does not contain a crosslinking aid.

  Furthermore, as the solar cell adhesive sheet A, a crosslinking aid sheet layer 1b that does not contain an organic peroxide and contains a crosslinking aid, and a peroxide that contains an organic peroxide and does not contain a crosslinking aid. It is more preferable that the sheet layers 1a are alternately laminated and integrated, and the outermost sheet layers on both sides are cross-linking aid sheet layers 1b and 1b containing no organic peroxide and containing a cross-linking aid. preferable.

  As described above, the peroxide sheet layer 1a and the crosslinking aid sheet layer 1b are alternately laminated and integrated, so that the peroxide sheet is melted when the sheet layers 1a and 1b are melted at the time of manufacturing the solar cell module. The organic peroxide contained in the layer 1a and the sheet layer 1b contained in the crosslinking aid sheet layer 1b can be mixed uniformly, and as a result, the solar cell adhesive sheet A is entirely formed. It can be uniformly and sufficiently crosslinked to have excellent heat resistance.

  Moreover, as shown in FIG. 4, the adhesive sheet A for solar cells contains a crosslinking aid sheet layer 1b containing no organic peroxide and containing a crosslinking aid, and containing an organic peroxide and crosslinking. It may have a two-layer structure in which a peroxide sheet layer 1a containing no auxiliary agent is laminated and integrated.

  Furthermore, the solar cell encapsulating sheet A includes a crosslinking aid sheet layer 1b that does not contain an organic peroxide and contains a crosslinking aid, and a peroxide that contains an organic peroxide and does not contain a crosslinking aid. Between the physical sheet layer 1a, a non-crosslinking agent-containing sheet layer that does not contain an organic peroxide and a crosslinking aid may be interposed.

  In the solar cell encapsulating sheet A, the peroxide sheet layer 1a and the crosslinking aid are present by interposing a non-crosslinking agent-containing sheet layer between the peroxide sheet layer 1a and the crosslinking aid sheet layer 1b. Preventing the coexistence of the organic peroxide contained in the peroxide sheet layer 1a and the crosslinking aid contained in the crosslinking aid sheet layer 1b at the interface with the sheet layer 1b. It is possible to more reliably prevent the peroxide sheet layer 1a and the crosslinking aid sheet layer 1b from staying or solidifying in the T-die when forming the solar cell encapsulating sheet, The peroxide sheet layer 1a and the crosslinking aid sheet layer 1b can be smoothly extruded from a T-die to obtain a solar cell encapsulating sheet A having a more uniform thickness.

  Moreover, the adhesive sheet A for solar cells may be a non-crosslinking agent-containing sheet layer in which the outermost sheet layers on both sides thereof do not contain an organic peroxide and a crosslinking aid. Thus, by using the outermost sheet layer of the adhesive sheet A for solar cells as a non-crosslinking agent-containing sheet layer, the non-crosslinking agent-containing sheet that is in direct contact with the T-die inner surface that is at a high temperature during film formation. Since the layer does not have crosslinkability, it is not cross-linked even by contact with the T-die, and the solar cell adhesive sheet A having a more uniform thickness can be obtained.

  When the thickness of the cross-linking agent-free sheet layer is thick, mixing of the organic peroxide in the peroxide sheet layer and the cross-linking aid in the cross-linking aid becomes insufficient during the production of the solar cell module, Since crosslinking of the entire solar cell encapsulating sheet may be insufficient and heat resistance may be lowered, the thickness is preferably 50 μm or less, more preferably 35 μm or less, particularly preferably 25 μm or less, and most preferably 1 to 10 μm.

  In addition, as long as it is in the range which does not impair the physical property of the adhesive sheet A for solar cells, an antioxidant, a ultraviolet absorber, a coupling agent, a flame retardant, etc. are added to a crosslinking agent non-containing sheet layer as needed. An agent may be contained.

  At the time of manufacturing the solar cell adhesive sheet A having four or more layers or a two-layer structure, a multi-layer extrusion apparatus having extruders corresponding to the number of layers of the solar cell adhesive sheet is prepared, and each sheet layer is configured in each extruder. The resin composition is supplied, melted and kneaded in each extruder, supplied to the feed block, and the sheet layers are laminated in the desired order from the T-die arranged at the tip of the feed block. The film can be formed by extruding into a sheet so as to be in an integrated state, and cooling and solidifying and winding the extruded molten sheet with a cooling roll. In the solar cell adhesive sheet A to be manufactured, when there are a plurality of sheet layers having the same configuration, the sheet layer extruder having the same configuration is shared, and a plurality of resin compositions extruded from the extruder are used. You may reduce the number of extruders by making it branch.

  Moreover, you may manufacture the adhesive sheet A for solar cells by laminating | stacking and integrating the film which comprises each sheet layer using general-purpose methods, such as extrusion lamination, other than the said manufacturing method.

  In the above description, the solar cell module B having a structure in which the solar cell elements are sealed and integrated from the upper and lower surfaces using the solar cell adhesive sheet A has been described. The solar cell adhesive sheet A of the present invention is described below. It can also be used for the solar cell module B having the structure.

  A solar battery cell 6 made of silicon, a compound semiconductor, or the like is laminated and integrated in a thin film shape on a transparent substrate 5, and a solar battery adhesive sheet A is laminated on the solar battery cell 6, and solar battery adhesion is performed. The laminated body which laminated | stacked the back surface protection material 4 on the sheet | seat A was produced, and this laminated body was heat-pressed under pressure reduction, the transparent substrate 5, the photovoltaic cell 6, the adhesive sheet A for solar cells, and the back surface protection material 4 Can be obtained (see FIG. 5). The solar battery cell 6 is sealed and integrated by the transparent substrate 5 and the solar battery adhesive sheet A.

A solar battery cell 8 made of silicon, a compound semiconductor, or the like is laminated and integrated on the substrate 7 in a thin film shape. A solar battery adhesive sheet A is laminated on the solar battery cell 8 and the solar battery cell is used. The laminated body which laminated | stacked the transparent protective material 3 on the adhesive sheet A is produced, this laminated body is heat-pressed under pressure reduction, the board | substrate 7, the photovoltaic cell 8, the adhesive sheet A for solar cells, and the transparent protective material 3 Can be obtained (see FIG. 6). The solar battery cell 6 is sealed and integrated with the substrate 7 and the solar battery adhesive sheet A.

  Also in the production of the solar cell module B, the organic peroxide contained in the peroxide sheet 1a in the solar cell adhesive sheet A and the crosslinking aid contained in the crosslinking aid sheet layer 1b are obtained. When mixed, the entire solar cell adhesive sheet A is sufficiently cross-linked by the coexistence of the organic peroxide and the cross-linking auxiliary agent, thereby imparting excellent heat resistance.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

(Examples 1-4, Comparative Examples 1-3)
A three-layer coextrusion apparatus is prepared in which three extruders are connected to one T die via one feed block, and two of these extruders serve as the outermost sheet layers on both sides. Table 1 shows two extruders for the cross-linking aid sheet layers 1b and 1b on both sides, for the sheet layers 1b and 1b and the remaining one for the peroxide sheet layer 1a as the central sheet layer. A predetermined amount of ethylene-vinyl acetate copolymer (vinyl acetate content: 28% by weight, melt flow rate: 20 g / 10 min), 2,5-di-methyl-2,5-di (benzoylperoxy) hexane (1 hour half-life temperature: 118.8 ° C.) and triallyl isocyanurate, and 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane, 2,6-di-tert-butyl-4-methylphenol 0 .1 part by weight and 2-hydroxy-4-methoxy While supplying the resin composition containing 0.3 part by weight of cibenzophenone, the predetermined amount of ethylene-vinyl acetate copolymer (vinyl acetate content shown in Table 1) was fed to the extruder for the peroxide sheet layer 1a. : 28% by weight, melt flow rate: 20 g / 10 min), low density polyethylene (tubular method, melt flow rate: 20 g / 10 min, melting point: 109 ° C.), 2,5-di-methyl-2,5- Di (benzoylperoxy) hexane (1 hour half-life temperature: 118.8 ° C.), 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (1 hour half-life temperature: 138 ° C.) and Triallyl isocyanurate and 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane, 0.1 part by weight of 2,6-di-t-butyl-4-methylphenol and 2-hydroxy-4- Butoxy were fed a resin composition containing the benzophenone 0.3 part by weight.

  Next, the resin composition is melted and kneaded at 120 ° C. in each of the three extruders, the molten resin composition is supplied to the feed block, and crosslinked by a T-die disposed at the tip of the feed block. Coextruded so that the auxiliary sheet layer 1b, the peroxide sheet layer 1a, and the crosslinking auxiliary sheet layer 1b are laminated and integrated in this order, and the thickness ratio shown in Table 1 is the solar cell. An adhesive sheet A was formed. Then, the molten solar cell adhesive sheet A immediately after being co-extruded from the T-die is supplied between the embossing roll and a rubber roll disposed opposite to the embossing roll, and the embossing roll is melted. The solar cell adhesive sheet A is pressed and subjected to embossing with a depth of 0.2 mm on the surface of the solar cell adhesive sheet A, and then wound while being cooled by a cooling roll, so that the thickness is 0.5 mm. A three-layer solar cell adhesive sheet A was obtained.

(Examples 5 and 6)
A five-layer coextrusion device is prepared in which five extruders are connected to one T-die via one feed block, and two of these extruders serve as the outermost sheet layers on both sides. For sheet layers 1b and 1b, one machine for the peroxide sheet layer 1a as the central sheet layer, the remaining two machines for the non-crosslinking agent-containing sheet layer, and the crosslinking aid sheet layers 1b and 1b on both sides In two extruders, ethylene-vinyl acetate copolymer (vinyl acetate content: 28% by weight, melt flow rate: 20 g / 10 minutes) 100 parts by weight, triallyl isocyanurate 0.75 parts by weight, 3-glycol Resin composition containing 0.1 part by weight of cidoxypropyltrimethoxysilane, 0.1 part by weight of 2,6-di-t-butyl-4-methylphenol and 0.3 part by weight of 2-hydroxy-4-methoxybenzophenone Supply the peroxide sheet In the extruder for layer 1a, ethylene-vinyl acetate copolymer (vinyl acetate content: 28 wt%, melt flow rate: 20 g / 10 min), 100 parts by weight, 2,5-di-methyl-2,5- Di (benzoylperoxy) hexane (1 hour half-life temperature: 118.8 ° C.) 0.83 part by weight, 3-glycidoxypropyltrimethoxysilane 0.1 part by weight, 2,6-di-t-butyl- A resin composition containing 0.1 part by weight of 4-methylphenol and 0.3 part by weight of 2-hydroxy-4-methoxybenzophenone is supplied, and an ethylene-vinyl acetate copolymer is fed to an extruder for a sheet layer not containing a crosslinking agent. 100 parts by weight of polymer (vinyl acetate content: 28% by weight, melt flow rate: 20 g / 10 min), 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane, 2,6-di-t-butyl- 4 They were fed a resin composition containing 0.1 parts by weight of methyl phenol and 0.3 parts by weight of 2-hydroxy-4-methoxybenzophenone.

  Next, the resin composition is melt-kneaded at 120 ° C. in each of the five extruders, the molten resin composition is supplied to the feed block, and crosslinked by a T-die disposed at the tip of the feed block. The auxiliary agent sheet layer 1b, the crosslinking agent-free sheet layer, the peroxide sheet layer 1a, the crosslinking agent-free sheet layer, and the crosslinking assistant sheet layer 1b are laminated and integrated in this order, and the thickness ratio is shown in Table 2. The adhesive sheet A for solar cells was formed by coextrusion so that the thickness ratio shown in FIG. Then, the molten solar cell adhesive sheet A immediately after being co-extruded from the T-die is supplied between the embossing roll and a rubber roll disposed opposite to the embossing roll, and the embossing roll is melted. Each of the sheet layers is exposed by being pressed against the solar cell adhesive sheet A, embossed to a depth of 0.2 mm on the surface of the solar cell adhesive sheet A, and then wound while being cooled by a cooling roll. A five-layer solar cell adhesive sheet A having a thickness ratio shown in 2 and having a thickness of 0.52 mm was obtained.

  As described above, when the solar cell adhesive sheet A was continuously formed by extrusion for 24 hours or more, in Examples 1 to 6, even after 24 hours had elapsed from the start of film formation, In the comparative examples 1 to 3, the adhesive sheet A for a solar cell having a uniform thickness was stably obtained without the ethylene-vinyl acetate copolymer staying in the T-die. The thickness of the both ends of the width direction of the adhesive sheet A for solar cells became thin, and it became impossible to obtain the adhesive sheet A for solar cells with uniform thickness.

  About the adhesive sheet A for solar cells obtained in Examples and Comparative Examples, the gel fraction before and after crosslinking and the temperature and humidity cycle test were conducted as follows, and the results are shown in Table 1.

(Gel fraction before crosslinking of adhesive sheet for solar cell)
A solar cell adhesive sheet A obtained 1 hour and 10 hours after the start of film formation was prepared. And the part (it described as "sheet edge part" in Table 1) spaced apart by 5 cm to the center side along the width direction from the edge of the width direction in these adhesive sheets A for solar cells, and the center part of the width direction About 0.2 g of a test piece was cut out from each of them (indicated as “sheet center” in Table 1). The exact balance value of this test piece was S (g).

Next, the test piece was immersed in 50 ml of xylene at 110 ° C. for 12 hours, the insoluble matter was filtered through a 200 mesh wire mesh, and the residue on the wire mesh was dried under reduced pressure at 80 ° C. for 4 hours to obtain a dry residue. The weight W (g) was weighed, and the gel fraction was calculated using the following formula (1).
Gel fraction (% by weight) = 100 × W / S (1)

(Gel fraction after crosslinking of solar cell adhesive sheet)
The solar cell adhesive sheet A 1 hour after the start of film formation was crosslinked by heating at 150 ° C. for 10 minutes, and a test piece was cut out from the center in the width direction of the crosslinked solar cell adhesive sheet A The gel fraction was measured in the same manner as described above.

1a Peroxide sheet layer, center sheet layer
1b Crosslinking aid sheet layer, outermost sheet layer 1 sheet layer 2 solar cell element 3 transparent protective material 4 back surface protective material A solar cell adhesive sheet B solar cell module

Claims (15)

An adhesive sheet for a solar cell in which two or more sheet layers containing a thermoplastic resin are laminated and integrated, a peroxide sheet layer containing an organic peroxide and no crosslinking aid, and an organic An adhesive sheet for solar cells, comprising a crosslinking aid sheet layer containing no peroxide and containing a crosslinking aid. The solar cell adhesive sheet according to claim 1, wherein the peroxide sheet layer and the crosslinking aid sheet layer are laminated and integrated adjacent to each other. The sun according to claim 1, wherein a non-crosslinking agent-containing sheet layer containing no organic peroxide and a crosslinking aid is interposed between the peroxide sheet layer and the crosslinking aid sheet layer. Battery sealing sheet. The solar cell adhesive sheet according to any one of claims 1 to 3, wherein the outermost sheet layers on both sides are crosslinking aid sheet layers. The solar cell according to any one of claims 1 to 3, wherein the outermost sheet layers on both sides are non-crosslinking agent-containing sheet layers not containing an organic peroxide and a crosslinking aid. Adhesive sheet. The thickness of a peroxide sheet layer and a crosslinking adjuvant sheet layer is 300 micrometers or less, The adhesive sheet for solar cells of any one of Claim 1 thru | or 5 characterized by the above-mentioned. The solar cell encapsulating sheet according to claim 4 or 5, wherein the thickness of the cross-linking agent-free sheet layer is 50 µm or less. The adhesive sheet for solar cells according to any one of claims 1 to 7, wherein the thermoplastic resin constituting the peroxide sheet layer is a polyethylene resin or ethylene-propylene rubber. A method for producing a solar cell encapsulating sheet using a multi-layer extrusion apparatus in which a plurality of extruders are connected to the same die, wherein at least two extruders are heated. A resin composition for a crosslinking aid sheet layer containing a plastic resin and a crosslinking aid and not containing an organic peroxide is supplied and melt kneaded, and at least one of the remaining extruders is heated. Supplying a resin composition for a peroxide sheet layer containing a plastic resin and an organic peroxide and not containing a crosslinking aid, and melt-kneading the resin composition for the crosslinking aid sheet layer and the peroxide By co-extruding the resin composition for the product sheet layer from the die, the peroxide sheet layer comprising the resin composition for the peroxide sheet layer and the resin composition for the crosslinking aid sheet layer The cross-linking aid sheet layer Reduction is and the manufacturing method of the sealing sheet for a solar cell, wherein the outermost sheet layers on both sides to produce a sealing sheet for solar cell comprising formed from the crosslinking aid sheet layer. A method for producing a solar cell sealing sheet using a multilayer extrusion apparatus in which three extruders are connected to the same die, wherein the thermoplastic resin is added to the two extruders. In addition, a resin composition for a crosslinking aid sheet layer containing a crosslinking aid and not containing an organic peroxide is supplied and melt-kneaded, and the remaining one extruder contains a thermoplastic resin and an organic peroxide. And a peroxide composition comprising the resin composition for the peroxide sheet layer by supplying a resin composition for the peroxide sheet layer that does not contain a crosslinking aid, melt-kneading, and co-extrusion from the die. A solar cell adhesive sheet comprising a cross-linking aid sheet layer made of the resin composition for the cross-linking aid sheet layer laminated and integrated on both surfaces of the sheet layer. Production method. A method for producing a solar cell encapsulating sheet using a multi-layer extrusion apparatus in which a plurality of extruders are connected to the same die, wherein at least two extruders are heated. Supply a resin composition for a crosslinking aid sheet layer containing a plastic resin and a crosslinking aid and not containing an organic peroxide, melt kneading, and thermoplastic to at least one of the remaining extruders Supplying a resin composition for a peroxide sheet layer containing a resin and an organic peroxide and not containing a crosslinking aid, and melt-kneading the thermoplastic resin to at least two of the remaining extruders A resin composition for a non-crosslinking agent-containing sheet layer containing an organic peroxide and no crosslinking aid is supplied and melt-kneaded to obtain a resin composition for the crosslinking aid sheet layer, the peroxide sheet Layer resin composition and cross-linking agent-free sheet By cross-extruding a resin composition for a layer from the die, a peroxide sheet layer composed of the resin composition for the peroxide sheet layer and a crosslink composed of the resin composition for the crosslinking aid sheet layer. The auxiliary sheet layer and the cross-linking agent-free sheet layer made of the resin composition for the cross-linking agent-free sheet layer are laminated and integrated so that the outermost sheet layers on both sides become the cross-linking auxiliary sheet layer and A solar cell encapsulating sheet comprising the above-described peroxide sheet layer and the above-mentioned cross-linking aid sheet layer, wherein the cross-linking agent-free sheet layer is interposed. Production method. A method for producing a solar cell encapsulating sheet using a multi-layer extrusion apparatus in which a plurality of extruders are connected to the same die, wherein at least two extruders are heated. Supply a resin composition for a crosslinking aid sheet layer containing a plastic resin and a crosslinking aid and not containing an organic peroxide, melt kneading, and thermoplastic to at least one of the remaining extruders Supplying a resin composition for a peroxide sheet layer containing a resin and an organic peroxide and not containing a crosslinking aid, and melt-kneading the thermoplastic resin to at least two of the remaining extruders A resin composition for a non-crosslinking agent-containing sheet layer containing an organic peroxide and no crosslinking aid is supplied and melt-kneaded to obtain a resin composition for the crosslinking aid sheet layer, the peroxide sheet Layer resin composition and cross-linking agent-free sheet By cross-extruding a resin composition for a layer from the die, a peroxide sheet layer composed of the resin composition for the peroxide sheet layer and a crosslink composed of the resin composition for the crosslinking aid sheet layer. The auxiliary sheet layer and the crosslinking agent-free sheet layer made of the resin composition for the crosslinking agent-free sheet layer are laminated and integrated so that the outermost sheet layers on both sides become the crosslinking agent-free sheet layer. The manufacturing method of the sealing sheet for solar cells characterized by manufacturing the sealing sheet for solar cells formed. The solar cell element is sealed and integrated from above and below by the solar cell adhesive sheet according to any one of claims 1 to 8, and a transparent protective material is laminated on the upper solar cell adhesive sheet. A solar cell module, wherein the back surface protective material is laminated and integrated on the lower solar cell adhesive sheet. The solar cells are formed in a thin film on the transparent substrate, and the solar cell adhesive sheet according to any one of claims 1 to 8 is laminated and integrated on the solar cells, A solar cell module, wherein solar cells are sealed by the transparent substrate and the solar cell adhesive sheet, and a back surface protective material is laminated and integrated on the solar cell adhesive sheet. A solar cell is formed in a thin film on the substrate, and the solar cell adhesive sheet according to any one of claims 1 to 8 is laminated and integrated on the solar cell, A solar cell module, wherein a solar cell is sealed by a substrate and the solar cell adhesive sheet, and a transparent protective material is laminated and integrated on the solar cell adhesive sheet.

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