JP6784186B2 - Manufacturing method of solar cell module - Google Patents

Description

The present invention relates to a method for manufacturing a solar cell module in which a solar cell element is resin-sealed between two films, and particularly to a method for manufacturing a flexible solar cell module having a fluorine-containing resin film having high weather resistance in the outermost layer.

Generally, a solar cell module has a glass substrate on the light receiving surface and a back surface protective material made of a glass substrate or PET (polyethylene terephthalate) film on the back surface, and is used as a sealing material for wrapping a solar electronic element. EVA (ethylene-vinyl acetate copolymer), polyolefin, and ionomer are used.

Since these encapsulants are hydrocarbon-based resins, they are particularly flammable, and when attached to the roof of a house, the light-transmitting substrate on the light-receiving surface side, such as glass, cracks due to the flame caused by the jumping fire, and EVA, etc. A phenomenon occurs in which the solar cell continues to burn due to ignition of the sealing material.

In addition, when the solar cell module burns, the backmost backsheet is mainly a PET film, so combustion cannot be stopped, and holes may open in the backsheet, causing glass and fragments of the solar cell element to fall. ..

In the case of a flexible thin-film solar cell, since a light-transmitting film is used on the light-receiving surface side and the backmost surface, the combustion of the module by the flame is further larger than that in the case where the light-receiving surface is glass.

International Publication No. 2013/06944 (Patent Document 1) contains a resin layer composed of a methacrylate resin and a polycarbonate resin, a core-shell type rubber particle, a phosphorus-based flame retardant, and a fluorine resin in order to obtain a flame retardant module. A flame-retardant resin laminate film including a layer made of the resin composition to be used, a manufacturing method, and a sheet for a solar cell module are disclosed, and this flame-retardant laminate film has passed the flame-retardant test "UL94HB evaluation". It is judged that it is effective as a surface material or a back sheet of a solar cell module.

However, EVA is assumed as the sealing material for the solar cell module of Patent Document 1, and acid is generated by the hydrolysis reaction of the sealing material by long-term outdoor exposure or an accelerated deterioration test under high temperature and high humidity conditions, which corrodes the electrodes. This may reduce the power generation efficiency of the solar cell.

Silicone resin is an example of a sealing material that does not cause a side reaction such as a hydrolysis reaction and has very high reliability. For example, Japanese Patent Application Laid-Open No. 2009-206212 (Patent Document 2) uses a silicone composition as a raw material composition for a sealing material for a solar cell module, and the cured product of this silicone composition is a gel-like or rubber-like silicone resin. If so, it becomes a flexible solar cell, and if it is a hard silicone resin, it becomes a solid and sturdy solar cell.

However, the raw material composition of the silicone encapsulant used in Patent Document 2 is liquid, and it is necessary to newly introduce a special device in order to apply it to the solar cell module, so no matter how high the performance is. There was a fatal problem that the solar cell market established with EVA sheets was not accepted.

International Publication No. 2013/069414 JP-A-2009-206212

The present invention has been made in view of the above circumstances, and the solar cell element can be sealed with a silicone cured product between two films by using a vacuum laminator device which is an existing solar cell module manufacturing device. An object of the present invention is to provide a method for manufacturing a battery module.

As a result of diligent studies to achieve the above object, the present inventors have layered an unvulvered curable silicone composition on each of the two films to be the light transmissive film and the back surface protective film in advance. When producing a laminated film that is tightly attached without voids, and when vacuum laminating two laminated films and a solar cell element so as to sandwich the solar cell element from the front and back between the silicone composition layers. We have found that by performing heating and pressing via a buffer material, it is possible to easily manufacture a solar cell module in which a solar cell element is sealed with a silicone cured product between two films without generating voids inside. The present invention has been reached.

That is, the present invention provides the following method for manufacturing a solar cell module in order to achieve the above object.
[1] In a method for manufacturing a solar cell module, which manufactures a solar cell module by sealing a solar cell element with a resin between at least two films whose light incident side films are light transmissive.
A step of directly providing a layered mirable type curable silicone composition that becomes light-transparent after being cured on one side of each of two films having a thickness of 10 to 200 μm to prepare a laminated film.
With the curable silicone composition layers of the two laminated films facing each other, a solar cell element is sandwiched between the curable silicone composition layers and laminated to form a laminate, and the laminate is evacuated. When arranging the laminate in the laminator device, a buffer material that buffers the transfer of pressure and heat from the device to the laminate is inserted between the laminate and then pressed while heating the laminate in the vacuum laminator device. A method for manufacturing a solar cell module, which comprises a step of curing a silicone composition layer and sealing a solar cell element.
[2] The method for manufacturing a solar cell module according to [1], wherein the cushioning material is an elastic sheet having a thickness of 0.5 to 10 mm made of an organic polymer material having heat resistance to heating in a vacuum laminator device. ..
[3] The method for manufacturing a solar cell module according to [1] or [2], wherein the cushioning material is made of sponge rubber having a type A durometer hardness of 30 or less.
[4] The solar cell module according to any one of [1] to [3], wherein the heat conductivity of the cushioning material is 0.02 W / (m · K) or more and 0.25 W / (m · K) or less. Production method.
[ 5 ] The method for manufacturing a solar cell module according to any one of [1] to [ 4 ], wherein the heating temperature of the vacuum laminator device is 70 to 160 ° C.
[ 6 ] The sun according to any one of [1] to [ 5 ], wherein the curable silicone composition layer is a millable type curable silicone composition laminated on a film by calendar processing or extrusion processing. How to manufacture a battery module.
[ 7 ] The curable silicone composition is
(A) The following average composition formula (I)
R ¹ _a SiO _{(4-a) / 2} (I)
(In the formula, R ¹ represents the same or dissimilar unsubstituted or substituted monovalent hydrocarbon group, and a is a positive number of 1.95 to 2.05.)
100 parts by mass of an organopolysiloxane having a degree of polymerization of 100 or more, represented by
(B) Aerosol silica with a specific surface area of more than 50 m ² / g 10 to 150 parts by mass,
(C) Curing Agent The method for producing a solar cell module according to any one of [1] to [ 6 ], which is a miraculous type silicone composition containing an effective amount for curing the component (A).
[ 8 ] The method for manufacturing a solar cell module according to any one of [1] to [ 7 ], wherein the curable silicone composition layer has a thickness of 0.02 to 3 mm.
[ 9 ] The method for manufacturing a solar cell module according to any one of [1] to [ 8 ], wherein the light transmissive film is made of a resin containing a fluorine atom.
[10] The vacuum laminator device has two adjacent decompression tanks partitioned by a diaphragm and a heating plate provided in one of the decompression tanks, and the step of sealing the solar cell element is The laminate is placed on the heating plate in the vacuum laminator device with the laminated body sandwiched between the cushioning materials so as to cover the laminated films on both the upper and lower surfaces thereof, the two pressure reducing tanks are depressurized, and the cushioning material is removed from the heating plate. Then, while maintaining the decompressed state in the decompression tank in which the laminate is arranged and the heated state of the laminate, the other decompression tank is set to atmospheric pressure or pressurized to be between the two decompression tanks. The method for manufacturing a solar cell module according to any one of [1] to [9], wherein the laminated body is compressed in the plate thickness direction by a diaphragm using a pressure difference via a cushioning material.
[11] The vacuum laminator device has another heating plate arranged on the upper side of the laminate in a pressure reducing tank in which the laminate is arranged, and the laminate is placed on both the upper and lower sides via a cushioning material. The method for manufacturing a solar cell module according to [10], which is heated.
[12] The production of the solar cell module according to any one of [1] to [11], wherein the solar cell element comprises a crystalline solar cell, an amorphous solar cell, an organic thin-film solar cell, or a CIGS solar cell. Method.

According to the present invention, the solar cell element is sandwiched under vacuum with a silicone composition layer formed on one side of each of the two films in close contact with each other, and pressed while heating, so that the silicone composition can be formed without taking in air bubbles. It can be cured, and as a result, the solar cell element can be sealed without creating a gap between the film and the cured silicone product or between the cured silicone product and the solar cell element. Further, by pressing the above two films while heating them through the cushioning material, the solar cell elements do not shrink or wrinkle or other appearance defects, and the solar cell elements are not damaged. Can be sealed. Further, according to this manufacturing method, it is possible to use a vacuum laminator device which is a solar cell module manufacturing device using a conventional EVA film, so that the sun does not need to prepare a new device for laminating. Battery modules can be manufactured.

It is sectional drawing which shows the structure of the laminated film which formed the curable silicone composition layer on the film. It is sectional drawing which shows the structure of the laminated body which laminated with the solar cell element sandwiching between the curable silicone composition layers in the state which the curable silicone composition layers of two laminated films face each other. It is sectional drawing which shows the arrangement state at the time of vacuum laminating process with respect to the laminated body shown in FIG. It is sectional drawing which shows the state which sealed the solar cell element by the laminating process by the vacuum laminator device. It is sectional drawing which shows the structure of the film-like laminate in which the curable silicone composition produced in Comparative Example 1 was formed into a layer. It is sectional drawing which shows the structure of the laminated body which laminated with the solar cell element sandwiched between the curable silicone composition layer of the two laminated films of the comparative example 1. FIG. It is sectional drawing which shows the arrangement state at the time of vacuum laminating process about the laminated body shown in FIG.

Hereinafter, a preferred embodiment of the method for manufacturing a solar cell module according to the present invention will be described with reference to the drawings.
FIG. 1 is an example of a cross section of a laminated film in which a curable silicone composition is formed in layers on a film. FIG. 2 is an example of a cross section of a laminated body in which a solar cell element is sandwiched between the curable silicone composition layers in a state where the curable silicone composition layers of two laminated films are opposed to each other. Further, FIG. 3 is an example of a cross section showing a state of the composite shown in FIG. 2 when vacuum laminating. FIG. 4 is an example of a cross section of a solar cell module in which a solar cell element is sealed with a silicone cured product between two films obtained by vacuum lamination.

The method for manufacturing a solar cell module of the present invention is mainly (i) manufacturing a laminated film composed of a film and a curable silicone composition layer, and (ii) superimposing a laminated film and a solar cell element (of a laminated body). (Formation), (iii) Cross-linking of the curable silicone composition using a vacuum laminator device, and modularization of solar cells (vacuum laminating).

(I) Laminated film manufacturing process (Fig. 1)
First, as shown in FIG. 1, a miraculous curable silicone composition is directly formed into a layer on one side of each of the two films 1 serving as a light-transmitting film and a back surface protective film, and the curable silicone composition layer 2a is formed. To form. Specifically, a light-transmitting film and a back surface protective film to be used as the outermost layer of the solar cell module are selected as the film 1, and an unvulcanized mirable silicone composition (silicone resin compound, etc.) to which a curing agent or the like is added in advance Silicone rubber compound) is layered with a thickness of 0.02 to 3.0 mm by calendar processing or extrusion processing, and is directly integrally laminated on the film 1. A film in which the curable silicone composition layer 2a is provided on one side of the film 1 is referred to as a laminated film. At this time, it is particularly important that the film 1 and the curable silicone composition layer 2a are brought into close contact with each other without gaps so that a peeled portion does not occur even when the laminated film is placed under reduced pressure. Since the curable silicone composition layer 2a laminated on the film 1 has tack (adhesiveness), a cover film 3 made of PE is covered to prevent sticking.

Here, the film 1 is a light transmissive film on the light receiving surface side of the solar cell module and a back surface protective film on the opposite side to the light receiving surface. Specifically, a PET (polyethylene terephthalate) film, a PC ( Polycarbonate) film, PI (polykimide) film, PPS (polyphenylene sulfide) film, PES (polyether sulfone) film, PEN (polyethylene naphthalate) film, PE (polyethylene) film, PP (polypropylene) film, ETFE (four-foot) Ethylene-ethylene copolymer), ECTFE (ethylene trifluoride), PFA (ethylene tetrafluoride-perfluoroalkyl vinyl ether copolymer), FEP (ethylene tetrafluoride-propylene hexafluoride copolymer), PVDF (vinylidene fluoride resin), PVF (vinyl fluoride resin), PMMA (acrylic) film, PA (polyamide) film, TPT (PVF / adhesive / PET / adhesive / PVF) and TPE (PVF / adhesive / Examples thereof include a back surface protective sheet for a solar cell made of a laminate shown in (PET / Adhesive / EVA) or (PVF / Adhesive / PET). Considering light transmission, weather resistance and stain resistance, PFA, ETFE and ECTFE films containing fluorine atoms are more preferable. The film containing fluorine atoms may be used as it is, but in order to improve the adhesiveness of the silicone rubber used as the sealing material, the film is surface-treated such as plasma treatment, corona treatment, and glow discharge treatment to make it hydrophilic. It is more effective to use the one. The light transmissive film and the back surface protective film may be different or the same.

The thickness of the film 1 is preferably 10 to 200 μm, more preferably 30 to 80 μm.

The curable silicone composition layer 2a is a mirable type curable silicone composition (silicone rubber composition or silicone resin composition) laminated on a film in an unvulcanized state by calendar processing or extrusion processing. Is preferable. In this unvulcanized curable silicone composition, for example, a liquid silicone polymer or silicone raw rubber is mixed with fumigant silica to reduce the fluidity so that the shape can be maintained, and a curing catalyst is added in advance to obtain a full compound. It is advisable to use a material and process it into a thin film on a resin film.

The silicone composition layer 2a requires long-term reliability of 20 years or more in outdoor use, including transparency (light transmission) and weather resistance as properties after curing, and therefore has high ultraviolet resistance and low modulus. Moreover, it is necessary that the adhesion with the film 1 is good.

The curable silicone composition constituting the silicone composition layer 2a may be crosslinked by any of a moisture-curable type, a UV-curable type, an organic peroxide-curable type, and an addition-curable type using a platinum catalyst. It is preferably composed of an addition-curable silicone composition having no by-products and less discoloration.

That is, the silicone composition used in the present invention is
(A) The following average composition formula (I)
R ¹ _a SiO _{(4-a) / 2} (I)
(In the formula, R ¹ represents the same or dissimilar unsubstituted or substituted monovalent hydrocarbon group, and a is a positive number of 1.95 to 2.05.)
100 parts by mass of an organopolysiloxane having a degree of polymerization of 100 or more, represented by
(B) Aerosol silica with a specific surface area of more than 50 m ² / g 10 to 150 parts by mass,
(C) Curing Agent A miraculous silicone composition containing an effective amount of curing the component (A) is preferable.

In the component (A), in the above average composition formula (I), R ¹ represents the same or different unsubstituted or substituted monovalent hydrocarbon group, and usually has 1 to 12 carbon atoms, particularly 1 to 8 carbon atoms. Those are preferable, and specifically, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group and an octyl group, a cycloalkyl group such as a cyclopentyl group and a cyclohexyl group, a vinyl group, an allyl group and a propenyl group. Alkenyl groups such as alkenyl groups, cycloalkenyl groups, phenyl groups, aryl groups such as tolyl groups, aralkyl groups such as benzyl groups and 2-phenylethyl groups, or some or all of the hydrogen atoms of these groups are halogen atoms or cyano groups. Examples thereof include a group substituted with the above, and a methyl group, a vinyl group, a phenyl group and a trifluoropropyl group are preferable, and a methyl group and a vinyl group are particularly preferable.

Specifically, the main chain of the organopolysiloxane consists of repeating dimethylsiloxane units, or a part of the dimethylpolysiloxane structure composed of repeating dimethylsiloxane units constituting the main chain includes a phenyl group, a vinyl group, and the like. Those introduced with a diphenylsiloxane unit having a 3,3,3-trifluoropropyl group or the like, a methylphenylsiloxane unit, a methylvinylsiloxane unit, a methyl-3,3,3-trifluoropropylsiloxane unit or the like are suitable. ..

In particular, the organopolysiloxane preferably has two or more alkenyl groups, cycloalkenyl groups and other aliphatic unsaturated groups in one molecule, and particularly preferably a vinyl group. In this case, it is preferable that 0.01 to 20 mol%, particularly 0.02 to 10 mol% of the total R ¹ is an aliphatic unsaturated group. The aliphatic unsaturated group may be bonded to a silicon atom at the end of the molecular chain, to a silicon atom in the middle of the molecular chain, or both, but at least the end of the molecular chain. It is preferably bonded to the silicon atom of. Further, a is a positive number of 1.95 to 2.05, preferably 1.98 to 2.02, and more preferably 1.99 to 2.01.

The organopolysiloxane of the component (A) is blocked with a triorganosyloxy group such as a trimethylsiloxy group, a dimethylphenylsiloxy group, a dimethylhydroxysiloxy group, a dimethylvinylsiloxy group, a methyldivinylsiloxy group, or a trivinylsiloxy group at the end of the molecular chain. Can be mentioned preferably. Particularly preferable ones include methyl vinyl polysiloxane, methylphenyl vinyl polysiloxane, methyl trifluoropropyl vinyl polysiloxane and the like.

Such an organopolysiloxane can be obtained, for example, by (co) hydrolyzing and condensing one or more of organohalogenosilanes, or by making cyclic polysiloxanes (trimers of siloxanes, tetramers, etc.) alkaline or acidic. It can be obtained by ring-opening polymerization using the catalyst of. These are basically linear diorganopolysiloxanes, but the component (A) may be a mixture of two or three or more kinds having different molecular weights (degrees of polymerization) and molecular structures.

The degree of polymerization of the organopolysiloxane is 100 or more, preferably 100 to 100,000, and particularly preferably 3,000 to 20,000. This degree of polymerization can be measured as a polystyrene-equivalent weight average degree of polymerization by gel permeation chromatography (GPC) analysis.

Reinforcing silica having a BET specific surface area of more than 50 m ² / g as a component (B) is added to maintain the shape of the unvulcanized silicone composition and to obtain a rubber composition having excellent mechanical strength after curing. Is. For this purpose, the BET specific surface area is preferably more than 50 m ² / g, more preferably 200 m ² / g or more. If the BET specific surface area is 50 m ² / g or less, not only the mechanical strength is weak, but also the shape of the unvulcanized silicone composition may be difficult to maintain. The upper limit is not particularly limited, but is usually 500 m ² / g or less.

Examples of the reinforcing silica of the component (B) include fuming silica (dry silica or fumed silica), precipitated silica (wet silica) and the like. Further, those whose surfaces are hydrophobized with chlorosilane, alkoxysilane, hexamethyldisilazane or the like are also preferably used. Here, the reinforcing silica may be used alone or in combination of two or more.

Commercially available products can be used as the reinforcing silica of the component (B), and for example, Aerosil series such as Aerosil 130, Aerosil 200, Aerosil 300, Aerosil R-812, Aerosil R-972, and Aerosil R-974 (Japan). Surface untreated or surface hydrophobized (ie, Tokuyama) such as Aerosil Co., Ltd., Cabosil MS-5, MS-7 (Cabot), Leoloseal QS-102, 103, MT-10 (Tokuyama). Fumed silica (hydrophilic or hydrophobic), Tokusir US-F (manufactured by Tokuyama Corporation), NIPSIL-SS, NIPSIL-LP (manufactured by Nippon Silica Co., Ltd.), etc. surface-untreated or surface-hydrophobicized Precipitated silica and the like can be mentioned.

The blending amount of the reinforcing silica of the component (B) is 10 to 150 parts by mass, preferably 30 to 120 parts by mass, and more preferably 50 to 50 parts by mass with respect to 100 parts by mass of the organopolysiloxane of the component (A). It is 100 parts by mass. If the amount of the component (B) is too small, not only the shape-retaining property of the unvulcanized silicone cannot be obtained, but also the reinforcing effect after curing may not be obtained. Dispersion of silica in the silicone polymer becomes difficult, and at the same time, the processability into a thin film may deteriorate.

The curing agent for the component (C) is not particularly limited as long as it can cure the component (A), but is a (a) addition reaction (hydrosilylation reaction) type curing agent widely known as a curing agent for silicone rubber. That is, a combination of an organohydrogenpolysiloxane (crosslinking agent) and a hydrosilylation catalyst, or (b) an organic peroxide is preferable, and both (a) and (b) can be used as known.

The organohydrogenpolysiloxane as a cross-linking agent in the above (a) addition reaction (hydrosilylation reaction) contains a hydrogen atom (SiH group) bonded to at least two silicon atoms in one molecule, and has the following average. Composition formula (II)
R ² _b H _c SiO _{(4-bc) / 2} (II)
(Here, R ² is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, preferably having no aliphatic unsaturated bond, but does not contain a phenylene group and an epoxy group. Specific examples include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group and hexyl group, unsaturated monovalent hydrocarbon groups such as cyclohexyl group, cyclohexenyl group and phenyl group, 3,3. It is a substituted monovalent hydrocarbon group such as a substituted alkyl group in which at least a part of hydrogen atoms of the above monovalent hydrocarbon group such as 3-trifluoropropyl group and cyanomethyl group is substituted with a halogen atom or a cyano group. Is 0.7 to 2.1, c is 0.01 to 1.0, and b + c is 0.8 to 3.0, preferably b is 0.8 to 2.0, and c is 0.2 to 1. 0 and b + c are indicated by positive numbers satisfying 1.0 to 2.5.)
Conventionally known organohydrogenpolysiloxanes shown in (1) can be applied. The molecular structure of the organohydrogenpolysiloxane may be linear, cyclic, branched, or three-dimensional network. In this case, the number of silicon atoms (or the degree of polymerization) in one molecule is preferably 2 to 300, particularly 4 to 200, which is liquid at room temperature. The hydrogen atom (SiH group) bonded to the silicon atom may be at the end of the molecular chain, at the side chain, or both, and at least two (usually 2 to 300) in one molecule. , Preferably 3 or more (for example, 3 to 200), more preferably about 4 to 150 are used.

Specifically, the organohydrogenpolysiloxane includes 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, methylhydrogencyclopolysiloxane, and methylhydrogensiloxane. -Dimethylsiloxane cyclic copolymer, tris (dimethylhydrogensiloxy) methylsilane, tris (dimethylhydrogensiloxy) phenylsilane, both-terminal trimethylsiloxy group-blocked methylhydrogenpolysiloxane, both-terminal trimethylsiloxy group-blocked dimethylsiloxane-methylhydro Gensiloxane copolymer, both-terminal dimethylhydrogensiloxy group-blocked dimethylpolysiloxane, both-terminal dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, both-terminal trimethylsiloxy group-blocked methylhydrogensiloxane / diphenylsiloxane Copolymer, both-terminal trimethylsiloxy group-blocking methylhydrogensiloxane / diphenylsiloxane / dimethylsiloxane copolymer, cyclic methylhydrogenpolysiloxane, cyclic methylhydrogensiloxane / dimethylsiloxane copolymer, cyclic methylhydrogensiloxane / diphenyl dimethylsiloxane copolymer, (CH ₃₎ a copolymer consisting of ₂ HSiO _1/2 units and SiO _4/2 units, and (CH _{3) 2} HSiO _1/2 units and SiO _4/2 units (C ₆ H ₅ ) In copolymers and the like consisting of _3/2 units of SiO and each of the above exemplified compounds, part or all of the methyl groups are other alkyl groups such as ethyl groups and propyl groups and aryl groups such as phenyl groups. Examples include those that have been replaced.

The blending amount of this organohydrogenpolysiloxane is 0.1 to 30 parts by mass, more preferably 0.1 to 10 parts by mass, and further preferably 0.3 with respect to 100 parts by mass of the organopolysiloxane of the component (A). It is preferably 10 parts by mass.

Further, in this organohydrogenpolysiloxane, the molar ratio of the hydrogen atom (that is, SiH group) bonded to the silicon atom in the component (C) to the alkenyl group bonded to the silicon atom in the component (A) is 0.5. It is preferably blended in an amount of 10 mol / mol, preferably 0.8 to 8 mol / mol, more preferably 2 to 6 mol / mol.

Further, as the hydrosilylation reaction catalyst used for the cross-linking reaction of the above (a) addition reaction (hydrosilylation reaction), known ones can be applied, for example, platinum black, second platinum chloride, platinum chloride acid, platinum chloride. Examples thereof include a reaction product of an acid and a monovalent alcohol, a complex of platinum chloride acid and olefins, a platinum-based catalyst such as platinum bisacetoacetate, a palladium-based catalyst, and a rhodium-based catalyst. The blending amount of the hydrosilylation reaction catalyst can be a catalytic amount, and is usually preferably in the range of 5 to 100 ppm in terms of the mass of the platinum group metal. If it is less than 1 ppm, the addition reaction may not proceed sufficiently and curing may be insufficient, and it is uneconomical to add an amount exceeding 1000 ppm, and an excess catalyst may color the cured product or the composition. It is not preferable because it adversely affects the storage stability of the product.

In addition to the above reaction catalyst, an addition reaction control agent may be used for the purpose of adjusting the curing rate or pot life. Specific examples thereof include ethynylcyclohexanol and tetramethyltetravinylcyclotetrasiloxane.

On the other hand, examples of the organic peroxide (b) include benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, p-methylbenzoyl peroxide, o-methylbenzoyl peroxide, and 2,4-dicumyl peroxide. 2,5-Dimethyl-bis (2,5-t-butylperoxy) hexane, di-t-butyl peroxide, t-butylperbenzoate, 1,6-hexanediol-bis-t-butylperoxycarbonate, etc. Can be mentioned.

The amount of the organic peroxide added (b) is preferably 0.1 to 15 parts by mass, particularly 0.2 to 10 parts by mass with respect to 100 parts by mass of the component (A). If the amount added is too small, the cross-linking reaction may not proceed sufficiently, resulting in a decrease in hardness and insufficient rubber strength. If the amount added is too large, not only is the cost unfavorable, but also a large amount of decomposition products of the curing agent is generated. May increase discoloration of the sheet.

In addition to the above components, the silicone composition used in the present invention includes an adhesive-imparting agent that imparts adhesiveness to films and solar cells as shown below, and flame retardancy, as long as the object of the present invention is not impaired. An imparting agent or the like can be added.

Here, as the adhesion-imparting agent, specifically, vinyl trimethoxylan, vinyl triethoxylan, allyltrimethoxylan, allyltriethoxylan, γ-glycidoxypropyltrimethoxylan, γ-glycidoxypropyltri. Ethoxylan, γ-glycidoxypropylmethyldimethoxylan, γ-glycidoxypropylmethyldiethoxylan, N-β (aminoethyl) -γ-aminopropyltrimethoxylan, N-β (aminoethyl) -γ- Various alkoxysilanes such as aminopropylmethyldimethoxylan, γ-aminopropyltrimethoxylan, γ-aminopropyltriethoxylan, γ-aminopropylmethyldimethoxylan, γ-aminopropylmethyldiethoxylan and their partial hydrolysis condensates. Examples thereof include addition reactants of triallyl isocyanurate and trimethoxysilane shown below, and various siloxane compounds having a SiH group and another functional group such as an epoxy group and an alkoxysilyl group. In the following formula, Me represents a methyl group.

Further, as another example of the adhesion-imparting agent, an organic silicon compound having at least one SiH group in one molecule and having at least one phenylene skeleton and having 1 to 100 silicon atoms, preferably 2 to 30 silicon atoms. Can be mentioned. Here, the "phenylene skeleton" includes those including a 2-hexavalent, particularly 2-4-valent, phenylene structure, naphthalene structure, and anthracene structure. This compound has at least one, usually 1 to 20, particularly about 2 to 10 SiH groups (that is, hydrogen atoms bonded to silicon atoms) in one molecule, and at least one, usually one. It has ~ 4 phenylene skeletons, and further has an epoxy group such as a glycidoxy group, an alkoxysilyl group such as a trimethoxysilyl group, a triethoxysilyl group and a methyldimethoxysilyl group, an ester group (COO group), an acrylic group and a methacryl group. , Anhydrous carboxy group, isocyanate group, amino group, amide group and other functional groups may be contained in one or more types, and the number of silicon atoms is 1 to 30, preferably 2 to 20, particularly about 4 to 10 linear chains. Organic silicon compounds such as cyclic or cyclic organosiloxane oligomers and organoalkoxysilanes can be preferably used.

（ｎは１〜４である。） Specific examples of such compounds include the compounds shown below.

(N is 1 to 4.)

から選ばれる基であり、Ｒ_w，Ｒ_xは非置換又は置換の一価炭化水素基である。ｑ＝１〜５０、ｈ＝０〜１００、好ましくはｑ＝１〜２０、ｈ＝１〜５０である。）で示される基、Ｒ”は

（Ｒ_w，Ｒ_xは上記と同様であり、ｙ＝０〜１００である。）
から選ばれる基であり、Ｙ’は

（Ｒ_w，Ｒ_x，ｑ，ｈは上記と同様である。）である。ｚ＝１〜１０である。〕

R _w and R _x are unsubstituted or substituted monovalent hydrocarbon groups. q = 1 to 50, h = 0 to 100, preferably q = 1 to 20, h = 1 to 50. The group indicated by), R "is

(R _w and R _x are the same as above, and y = 0 to 100.)
Y'is the base chosen from

(R _w , R _x , q, h are the same as above.). z = 1-10. ]

Next, regarding the flame retardant-imparting component, known ones can be used. Specific examples thereof include triazole compounds such as platinum compounds, fumed titanium oxide, red iron oxide (Fe ₂ O ₃ and Fe ₃ O ₄ ), carbon black, iron oxide, titanium oxide and benzotriazole, and derivatives thereof. Flame retardancy can also be imparted by adding a filler such as crystalline silica or alumina to relatively reduce the siloxane content.

The silicone composition of the present invention can be obtained by kneading a predetermined amount of the above-mentioned components with a two-roll, kneader, Banbury mixer or the like.

The silicone composition thus prepared preferably has a plasticity of 150 to 1,000, more preferably 200 to 800, and particularly preferably 250 to 600. If the degree of plasticity is less than 150, it becomes difficult to maintain the shape of the uncured sheet, and the tack becomes strong, making it difficult to use. Further, if it exceeds 1,000, the cohesiveness is lost and the sheeting process becomes difficult. The plasticity can be measured according to JIS K 6249: 2003.

In the case of silicone rubber, the hardness of the curable silicone composition is preferably 5 to 80, more preferably 40 to 70, as the type A durometer hardness.

When the silicone composition of the present invention is directly molded into a layer on the film 1, the molding method is not particularly limited, but extrusion molding, calender molding and the like are used. At this time, the thickness of the silicone composition is preferably 0.02 to 3.0 mm, more preferably 0.2 to 0.8 mm. If it is thinner than 0.02 mm, there may be a problem in following the uneven cell surface when sandwiching the solar cell element later, and even if it is thicker than 3.0 mm, the weight of the laminated film will only increase. The effect of thickening is small.

Since the silicone composition of the present invention is in an uncured state, it has a tack (adhesiveness) on the surface unlike a general polymer resin sheet. Therefore, as shown in FIG. 1, after producing a laminated film of the film 1 of the light transmissive film and the back surface protective film and the unsulfurized silicone composition layer 2a, the unsulfurized silicone composition layer 2a When an embossed cover film 3 made of PE (polyethylene) or the like is placed on the top, a composite composed of the film 1, the curable silicone composition layer 2a, and the cover film 3 can be wound up, which is preferable. .. In FIG. 1, when a laminated film composed of the film 1 and the silicone composition layer 2a is used, the cover film 3 such as PE is peeled off before use.

(Ii) Laminated body forming step (FIG. 2)
The PE cover film 3 is peeled off from the two sets of the above-mentioned laminated films (the laminated film of the film 1 and the unsulfurized silicone composition layer 2a), and as shown in FIG. 2, the silicone composition layer of one of the laminated films is peeled off. The solar cell element 4 to be sealed is arranged so as to be in contact with 2a, and the other laminated film is laminated so that the curable silicone composition layer 2a is in contact with the solar cell element 4. That is, with the curable silicone composition layers 2a of the two laminated films facing each other, the solar cell element 4 is sandwiched between the curable silicone composition layers 2a and laminated to form "film 1 (light). The laminate is composed of "transparent film) / curable silicone composition layer 2a / solar cell element 4 / curable silicone composition layer 2a / film 1 (back surface protective film)".

The type of the solar cell element 4 is not particularly limited, and for example, a crystalline solar cell, an amorphous solar cell, an organic thin film solar cell, or a CIGS solar cell can be used.

(Iii) Vacuum laminating process (Fig. 3)
When arranging the laminated body in the vacuum laminator device, a cushioning material that buffers the transfer of pressure and heat from the device to the laminated body is inserted between the laminated body and the vacuum laminator device. Specifically, as shown in FIG. 3, a sheet-shaped cushioning material 5 having a larger area than the laminated body is arranged on both upper and lower surfaces of the laminated body produced in the above step (ii) so as to cover the laminated body, and a vacuum laminator. It is arranged at a predetermined position of the device (on the heating plate 21 in FIG. 3). At this time, the configuration in which the cushioning material 5 is arranged on both the upper and lower surfaces of the laminated body is the mode in which the effect of the present invention is most obtained. The effect of is obtained.

Here, the cushioning material 5 cushions the transfer of pressure and heat from the vacuum laminator device to the laminated body, and immediately after the laminated body is placed in the vacuum laminator device, the temperature suddenly increases due to the heat from the heating plate 21. It has the effect of suppressing the rise and making the pressure of the laminate by the diaphragm 22 uniform by utilizing the pressure difference between the two compartments separated by the diaphragm (elastic film) 22. That is, the cushioning material 5 does not completely insulate the heat from the heating plate 21, but slows down the speed of heat transfer to the laminate (slows the rate of temperature rise) to bring the laminate to a predetermined temperature. It is for heating. Further, the cushioning material 5 is also for suppressing the pressing force of the diaphragm 22 from being locally applied to the laminated body so that the pressing force is uniformly applied to the laminated body.

The cushioning material 5 is preferably an elastic sheet made of an organic polymer material and having a thickness of 0.5 to 10 mm, and examples thereof include a rubber sheet (elastomer sheet) and a sponge sheet (sponge rubber sheet). Since the cushioning material 5 is required to have a heat-absorbing property in contact with the heating plate 21, the material of the cushioning material 5 is preferably an organic polymer material having heat resistance to heating in a vacuum laminating apparatus, and silicone rubber and urethane. Examples include rubber, polyamide-based elastomer, and polyimide-based elastomer. Of these, silicone rubber is preferable in that it does not affect the durability and the crosslinkability of the silicone composition used in the present invention, has excellent cushioning properties, and is relatively lightweight even in a large area, so that it is excellent in handleability. Silicone sponge is preferable in that respect.

In terms of heat buffering property, the thermal conductivity of the cushioning material 5 is preferably 0.02 W / (m · K) or more and 0.25 W / (m · K) or less, preferably 0.05 W / (m · K) or less. ) Or more, more preferably 0.20 W / (m · K) or less. If the thermal conductivity exceeds 0.25 W / (m · K), the curing reaction of the silicone composition starts in the step of defoaming under reduced pressure, which may cause voids in the heating pressing step, which is not preferable. This thermal conductivity is measured based on JIS R 2616 for rubber sheets, and according to the Shibayama method (acetone-benzene method) ASTM D4351 or JIS A 1414-2: 1999 for sponge sheets. It is measured based on.

In terms of cushioning property against pressure, the hardness of the cushioning material 5 is preferably a type A durometer hardness measured based on JIS K: 6249: 2003 of 30 or less, and a type E durometer hardness of 35. More preferably. In this case, a silicone sponge sheet is particularly suitable.

The thickness of the cushioning material 5 is preferably 0.5 to 10 mm, more preferably 3 to 7 mm from the viewpoint of cushioning the transfer of pressure and heat from the vacuum laminator device to the laminate. If it is thinner than 0.5 mm, the buffer capacity is small, and the sealing property may deteriorate due to a rapid temperature rise of the laminate. If it exceeds 10 mm, the buffer capacity is sufficient, but from the heating plate 21 of the vacuum laminator device. The heat is not easily transferred to the silicone composition layer 2a of the laminate, and it is necessary to make the heat curing time very long.

As shown in FIG. 3, after arranging the laminate in the vacuum laminator device via the cushioning material 5, defoaming is performed for a certain period of time in the reduced pressure space, and then the laminate is heated by the heating plate 21 and pressed by the diaphragm 22. Then, the silicone composition layer 2a is cured (while heating with a heating plate from above as necessary) to seal the solar cell element.

Specifically, as the vacuum laminator device, a laminator device for manufacturing a general-purpose solar cell module having two adjacent decompression tanks separated by a diaphragm (flexible film body) 22 can be adopted, for example, in one decompression tank. As shown in FIG. 3, the laminate is arranged via the cushioning material 5 to reduce the pressure in the two pressure reducing tanks to bring the laminate into a substantially vacuum state and arrange the laminate 21 (and the upper side of the laminate not shown). The laminated body is started from one side (or both upper and lower sides) of the laminated body via the buffer material 5 from the other heating plate), and then the decompression state in the decompression tank in which the laminated body is arranged is maintained, and the other side. The decompression of the decompression tank is released to normal pressure (atmospheric pressure) or pressurized to use the pressure difference between the two decompression tanks, and the diaphragm 22 compresses the laminate in the plate thickness direction via the buffer material 5. To do.

When the laminate is arranged in the reduced pressure space in the vacuum laminating apparatus, the degree of reduced pressure is not particularly limited, but is preferably −0.08 to −0.10 MPa. The degree of decompression here is the gauge pressure of the space in which the laminate is placed. That is, after decompressing (vacuum) the upper and lower spaces through the diaphragm, if only the upper space is opened to atmospheric pressure, the diaphragm will stick to the lower pressure, but at this time the atmospheric pressure in the lower space and the upper space The difference between them is the pressing pressure of the diaphragm.

Further, the heating / pressing conditions in the vacuum laminator device are also appropriately selected, but after heating with a heating plate 21 at 70 to 160 ° C., particularly 100 to 150 ° C., vacuum decompression for 3 to 5 minutes is performed, and then the other It is preferable to press the laminate with the diaphragm 22 via the cushioning material 5 for 5 to 30 minutes with the pressure reducing tank open to atmospheric pressure. This pressing force is preferably 0.08 to 0.1 MPa, more preferably 0.09 to 1.0 MPa.

At the time of this pressing, cross-linking of the silicone composition of the silicone composition layer 2a is promoted, and the silicone composition is cured and adheres to the film 1 and the solar cell element 4. If the heating temperature is lower than 70 ° C, the curing rate is slow and curing may not be completed within the molding time, and if it is higher than 160 ° C, the curing rate will be faster and curing will start during evacuation before pressing. As a result, there is a possibility that a gap may remain due to poor pressing. The laminate once obtained by heat molding may be post-cured at 100 to 150 ° C. for about 10 minutes to 10 hours.

As a result, the curable silicone composition layers 2a of each of the two films 1 are pressed against each other under reduced pressure, so that the silicone composition layers 2a are in close contact with each other without incorporating voids such as air bubbles. It will be in the state of. Then, it is heated in this state and the silicone composition constituting the silicone composition layer 2a is cured to become the silicone sealing layer 2, and as a result, the solar cell element 4 is sealed in the silicone sealing layer 2. The solar cell module 10 is completed (FIG. 4).

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Example 1]
Organopolysiloxane 100 parts by mass, BET ratio, consisting of 99.825 mol% of dimethylsiloxane unit, 0.15 mol% of methylvinylsiloxane unit, 0.025 mol% of dimethylvinylsiloxane unit, and an average degree of polymerization of about 6,000. 70 parts by mass of dry silica Aerosil 300 (manufactured by Nippon Aerosil Co., Ltd.) with a surface area of 300 m ² / g, 16 parts by mass of hexamethyldisilazane as a dispersant, and 4 parts by mass of water are added and kneaded with a kneader at 170 ° C. The compound was prepared by heat treatment for 2 hours.
C-25A (platinum catalyst) / C-25B (organohydrogenpolysiloxane) (both manufactured by Shin-Etsu Chemical Industry Co., Ltd.) were added to 100 parts by mass of the compound as an addition cross-linking curing agent. 0 parts by mass and 0.25 parts by mass of the adhesion-imparting agent represented by the following chemical formula were added after kneading with two rolls and mixed uniformly to obtain a milky white resin composition in an unvulcanized state.

[Preparation of laminated film of film and unvulcanized silicone composition layer]
On the surface of an ETFE film with a thickness of 50 μm (trade name: Aflex 50MW500DCS (manufactured by Asahi Glass Co., Ltd.)), the unvulcanized silicone resin composition obtained as described above is curable to a thickness of 0.5 mm. Lamination processing was performed so as to form a silicone composition layer. This processing was performed using an inverted L-shaped 4-calender roll, and a PE embossed film (ALEF type, manufactured by Ishijima Chemical Industry Co., Ltd .; thickness 0.) was used as a cover film on the surface of the curable silicone composition layer. 1 mm) was laminated to prepare a laminated film in which the surface of the ETFE film (film 1) / curable silicone composition layer 2a / embossed film (cover film 3) having the configuration shown in FIG. 1 was protected by a cover film. .. The workability for producing this laminated film was good.
Next, two laminated films with a cover film cut into 500 mm squares were prepared.

[Superposition of the above laminated film and solar cell (formation of laminated body)]
The cover film is peeled off from one of the laminated films obtained as described above, and a 156 mm square p-type single crystal cell for a solar cell is sized as an enclosure on the curable silicone composition layer of the laminated film. The solar cell strings arranged in (2 x 2 rows vertically and horizontally) were placed. Next, after the cover film was peeled off from the other laminated film, the unvulcanized silicone composition layer of the laminated film was placed so as to be in contact with the solar cell strings to prepare a laminated body as shown in FIG.

[Crosslinking of silicone composition layer using vacuum laminator device and modularization of solar cells (vacuum laminating process)]
600 mm square silicone sponge sheets (commodity) on both the upper and lower sides of the laminate composed of the "ETFE film / curable silicone composition layer / crystalline solar cell / curable silicone composition layer / ETFE film" obtained above. name SPO-35R1, thickness 5Mmt, type E durometer hardness 35, thermal conductivity of ^{5.0 × 10 -2 W / (m} · K) ( Shibayama formula (acetone - compliant benzene method) ASTM D4351): Tigers polymer (Manufactured by Co., Ltd.) is arranged so as to cover the laminate, and is arranged on one heating plate 21 of two pressure reducing tanks separated by a diaphragm 22 in a vacuum laminator device as shown in FIG. After depressurizing both of the two decompression tanks for 5 minutes while being heated by the heating plate 21 at 140 ° C., the decompression tank side on which the laminate is not arranged is opened to atmospheric pressure for 30 minutes to be crimped with the diaphragm 22. , The curable silicone composition layer of the laminate is cured, and as shown in FIG. 4, "ETFE film (film 1) / silicone sealing layer 2 / crystalline solar cell (solar cell element 4) / silicone sealing" A solar cell module made of "Layer 2 / ETFE film (film 1)" was produced.

[Example 2]
An amorphous solar cell (manufactured by FWAVE Co., Ltd.) having a size of 400 × 400 mm was used as the solar cell, and a solar cell module was produced in the same manner as in Example 1 except for the above. That is, in the same manner as in Example 1, two sets of laminated films having the surface of the ETFE film (film 1) / curable silicone composition layer 2a / embossed film (cover film 3) shown in FIG. 1 protected by the cover film. Made. The workability for producing this laminated film was good. Next, using this laminated film, "ETFE film (film 1) / curable silicone composition layer 2a / amorphous solar cell (solar cell element 4') / curable silicone composition layer 2a / ETFE film (film 1)" A 600 mm square silicone sponge sheet (trade name SPO-35R1, thickness 5 mmt, type E durometer hardness 35, thermal conductivity 5.0 × 10) was formed on both the upper and lower sides of the laminate. ^-2 W / (m · K) (Shibayama type (acetone-benzene method) based on ASTM D4351): manufactured by Tigers Polymer Co., Ltd.) is arranged so as to cover the laminate, and the vacuum laminator is the same as in Example 1. In the apparatus, the laminate was placed on one heating plate of two pressure reducing tanks separated by a diaphragm, and as a vacuum laminating process, the laminate was decompressed for 5 minutes in a state of being heated by a heating plate at 140 ° C. By crimping the non-arranged pressure reducing tank side with a diaphragm by opening the pressure reducing tank side for 30 minutes, the curable silicone composition layer of the laminated body is cured, and the "ETFE film (film 1) / silicone sealing layer 2" is cured. / Amorphous solar cell (solar element 4') / Silicone sealing layer 2 / ETFE film (film 1) "was produced.

[Comparative Example 1]
In the same manner as in Example 1, a milky white resin composition (silicone composition) was kneaded using two rolls and processed into a sheet having a thickness of 0.5 mm to obtain a curable silicone composition sheet 92a. , Both sides of the silicone composition sheet 92a are sandwiched between two PE embossed films (ALEF type, manufactured by Ishijima Chemical Industry Co., Ltd .; thickness 0.1 mm) as a cover film 3, and are shown in FIG. A laminated sheet like this was obtained.

[Lastination of curable silicone composition sheet and ETFE film (preparation of laminated film), and superposition of laminated film and solar cell (formation of laminated body)]
The cover film 3 on one side of the laminated sheet made of the embossed film (cover film 3) / curable silicone composition sheet 92a / embossed film (cover film 3) is peeled off, and the exposed curable silicone composition sheet 92a is thickened. A 50 μm ETFE film (trade name: Aflex 50MW500DCS (manufactured by Asahi Glass Co., Ltd.)) is attached to cover the surface composed of ETFE film (film 1) / curable silicone composition sheet 92a / embossed film (cover film 3). Two sets of film-protected laminated films were produced. In this case, since the thin ETFE film is handled alone, it is difficult to handle it, and the workability of laminating is poor.
Next, the cover film was peeled off from this laminated film, and the same amorphous solar cell as in Example 2 was placed as an enclosure on the curable silicone composition sheet of the laminated film. Next, after peeling the cover film from the other laminated film, the unvulverized silicone composition sheet of the laminated film is placed so as to be in contact with the solar cell, and the "ETFE film (film 1) as shown in FIG. 6 is placed. ) / Curable Silicone Composition Sheet 92a / Amorphous Solar Cell Cell (Solar Cell Element 4') / Curable Silicone Composition Sheet 92a / ETFE Film (Film 1) ”was produced. The structure of the laminate in which the amorphous solar cell is sandwiched between the curable silicone composition sheet 92a is the same as in Example 2, but a gap 1v is observed between the film 1 and the curable silicone composition sheet 92a. Was done.

[Crosslinking of silicone composition sheet using vacuum laminator device and modularization of solar cells (vacuum laminating process)]
A 600 mm square, 200 μm-thick fluororesin-based sheet 95 is arranged on both the upper and lower surfaces of the above-mentioned laminate so as to cover the laminate in order to prevent the vacuum laminator device from adhering to the heating plate or the like. As shown in FIG. 7, in the vacuum laminator device, the vacuum laminator device is arranged on one heating plate 21 of two pressure reducing tanks separated by a diaphragm 22, and as a vacuum laminating treatment, the two pressure reducing plates are heated by the heating plate 21 at 130 ° C. After depressurizing both tanks for 5 minutes, the pressure-reducing tank side on which the laminate is not arranged is opened to atmospheric pressure for 30 minutes and then pressure-bonded with the diaphragm 22 to cure the curable silicone composition sheet of the laminate. A solar cell module composed of "ETFE film (film 1) / silicone sealing layer / amorphous solar cell (solar cell element 4') / silicone sealing layer / ETFE film (film 1)" was produced.

[Comparative Example 2]
A laminate was prepared in the same manner as in Comparative Example 1. That is, an ETFE film (trade name: Aflex 50MW500DCS) is formed on a curable silicone composition sheet 92a obtained by processing the same resin composition (silicone composition) as in Example 1 into a sheet shape using two rolls so as to have a thickness of 0.5 mm. Using two sets of laminated films (manufactured by Asahi Glass Co., Ltd.), the thin-film solar cell is sandwiched between curable silicone composition sheets to form "ETFE film (film 1) / curable silicone composition sheet". A laminate composed of "92a / thin film solar cell (solar cell element) / curable silicone composition sheet 92a / ETFE film (film 1)" was produced. In addition, when producing a laminated film, since the thin ETFE film is handled alone, it is difficult to handle it, and the workability of laminating is poor.
Then, the upper and lower surfaces of the laminate, the silicone sponge sheet 600mm square (trade name SPO-35R1, thickness 5Mmt, type E durometer hardness 35, thermal conductivity of ^{5.0 × 10 -2 W / (m} · K) (Shibayama method (acetone-benzene method) based on ASTM D4351): manufactured by Tigers Polymer Co., Ltd.) was arranged so as to cover the laminate, and was separated by a diaphragm in a vacuum laminator device as in Example 1. A pressure reducing tank in which the laminate is not arranged after being placed on one of the heating plates of the two pressure reducing tanks and heated by the heating plate at 140 ° C. for 5 minutes in the state of being heated by the heating plate at 140 ° C. By crimping the side with a diaphragm by opening the atmospheric pressure for 30 minutes, the curable silicone composition sheet of the laminate is cured, and "ETFE film (film 1) / silicone sealing layer / thin film solar cell / silicone". A solar cell module made of "sealing layer / ETFE film (film 1)" was produced.

[Comparative Example 3]
In Example 2, the fluororesin-based sheet 95 used in Comparative Example 1 was used instead of the silicone sponge sheet (cushioning material 5) inserted in the vacuum laminating apparatus to perform the vacuum laminating treatment, and the other cases were the same as in Example 2. A solar cell module was manufactured in the same manner. That is, in the same manner as in Example 2, "ETFE film (film 1) / curable silicone composition layer 2a / amorphous solar cell (solar cell element 4') / curable silicone composition layer 2a / ETFE film (film 1). ) ”Is formed, and a fluororesin-based sheet 95 having a size of 600 mm square and a thickness of 200 μm is arranged on both the upper and lower surfaces of the laminate so as to cover the laminate, and a vacuum laminator is used as in Comparative Example 1. In the apparatus, it is placed on one heating plate 21 of two pressure reducing tanks separated by a diaphragm, and as a vacuum laminating treatment, the two pressure reducing tanks are decompressed for 5 minutes in a state of being heated by a heating plate at 130 ° C. The curable silicone composition layer of the laminate was cured by crimping with a diaphragm by opening the pressure reducing tank side at atmospheric pressure for 30 minutes, and the "ETFE film (film 1) / silicone sealing layer" was cured. / Amorphous solar cell (solar element 4') / Silicone sealing layer / ETFE film (film 1) ”was produced.

[Evaluation methods]
(1) Laminating workability of laminated film It was evaluated whether or not the laminating workability of the laminated film was easy. Specifically, it was evaluated whether or not the thin film 1 would cause a problem in laminating the laminated film, and if there was no problem, it was good (mark: 〇), and it became a problem because the film was difficult to handle. The case was regarded as defective (mark: ×).
(2) Appearance evaluation of the solar cell module The appearance evaluation of the solar cell module obtained as described above was visually evaluated to confirm the presence or absence of molding defects such as voids (poor sealing) and film elongation. At this time, if a gap is found between the film and the silicone sealing layer, or if a gap is found between the solar cell and the silicone sealing layer, it is determined that the sealing is defective (mark: ×). did. Further, when a partial elongation was observed in the film or a wrinkle was observed in the thin solar cell element, it was determined to be a molding defect (mark: ×). When no sealing defect or molding defect was observed, it was judged to be good (mark: 〇).
(3) Comprehensive evaluation If either (1) or (2) above was defective, it was rejected (mark: ×), and if both were good, it was accepted (mark: 〇).
The results are shown in Table 1.

Based on the above results, the solar cell is sandwiched between laminated films in which an unvulcanized curable silicone composition layer is laminated in advance on the film, and vacuum lamination is performed using a cushioning material made of a silicone sponge sheet. It was possible to modularize a solar cell that was easy and had no appearance defects and had improved sealing reliability. This makes it possible to provide a lightweight and flexible silicone-sealed solar cell module. In the comparative example, a thin film was pasted on the unvulcanized curable silicone composition sheet processed into a sheet and laminated, but the tack of the unvulcanized curable silicone composition sheet and the handling of the thin film were difficult. , Both could not be completely adhered without containing voids, and as shown in FIG. 6, voids remained between the film 1 and the curable silicone composition sheet 92a, and partially received light after the vacuum laminating treatment. The result was that the film on the front side and the film on the back protection side were stretched and thinned. Further, when the cushioning material was not used, the laminated body was rapidly heated, resulting in wrinkles in the laminated body.

Although the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments shown in the drawings, and other embodiments, additions, changes, deletions, etc. Can be changed within the range that can be conceived, and is included in the scope of the present invention as long as the effects of the present invention are exhibited in any of the embodiments.

1 film 1v void
2 Silicone sealing layer 2a Curable silicone composition layer 3 Cover film 4 Solar cell element 5 Cushioning material 10 Solar cell module 21 Heating plate 22 Diaphragm 92a Curable silicone composition sheet 95 Fluororesin-based sheet

Claims (12)

In a method for manufacturing a solar cell module, which manufactures a solar cell module by sealing a solar cell element with a resin between at least two films in which the light incident side film is light transmissive.
A step of directly providing a layered mirable type curable silicone composition that becomes light-transparent after being cured on one side of each of two films having a thickness of 10 to 200 μm to prepare a laminated film.
With the curable silicone composition layers of the two laminated films facing each other, a solar cell element is sandwiched between the curable silicone composition layers and laminated to form a laminate, and the laminate is evacuated. When arranging the laminate in the laminator device, a buffer material that buffers the transfer of pressure and heat from the device to the laminate is inserted between the laminate and then pressed while heating the laminate in the vacuum laminator device. A method for manufacturing a solar cell module, which comprises a step of curing a silicone composition layer and sealing a solar cell element. The method for manufacturing a solar cell module according to claim 1, wherein the cushioning material is an elastic sheet having a thickness of 0.5 to 10 mm and made of an organic polymer material having heat resistance to heating in a vacuum laminator device. The method for manufacturing a solar cell module according to claim 1 or 2, wherein the cushioning material is made of sponge rubber having a type A durometer hardness of 30 or less. The method for manufacturing a solar cell module according to any one of claims 1 to 3, wherein the heat conductive material of the cushioning material has a thermal conductivity of 0.02 W / (m · K) or more and 0.25 W / (m · K) or less. The method for manufacturing a solar cell module according to any one of claims 1 to 4 , wherein the heating temperature of the vacuum laminator device is 70 to 160 ° C. The production of the solar cell module according to any one of claims 1 to 5 , wherein the curable silicone composition layer is a millable type curable silicone composition laminated on a film by calendar processing or extrusion processing. Method. The curable silicone composition is
(A) The following average composition formula (I)
R ¹ _a SiO _{(4-a) / 2} (I)
(In the formula, R ¹ represents the same or dissimilar unsubstituted or substituted monovalent hydrocarbon group, and a is a positive number of 1.95 to 2.05.)
100 parts by mass of an organopolysiloxane having a degree of polymerization of 100 or more, represented by
(B) Aerosol silica with a specific surface area of more than 50 m ² / g 10 to 150 parts by mass,
(C) Curing agent The method for producing a solar cell module according to any one of claims 1 to 6 , which is a miraculous type silicone composition containing an effective amount for curing the component (A). The method for manufacturing a solar cell module according to any one of claims 1 to 7 , wherein the thickness of the curable silicone composition layer is 0.02 to 3 mm. The method for manufacturing a solar cell module according to any one of claims 1 to 8 , wherein the light transmissive film is made of a resin containing a fluorine atom. The vacuum laminator device has two adjacent decompression tanks separated by a diaphragm and a heating plate provided in one of the decompression tanks, and the step of sealing the solar cell element is a step of sealing the laminated body. It is placed on a heating plate in the vacuum laminator device in a state of being sandwiched between cushioning materials so as to cover the laminated films on both the upper and lower surfaces, and the two pressure reducing tanks are depressurized and laminated from the heating plate via the cushioning material. The body is heated, and then the pressure difference between the two decompression tanks is increased by setting the pressure in the other decompression tank to atmospheric pressure or pressurizing while maintaining the decompression state in the decompression tank in which the laminate is arranged and the heated state of the laminate. The method for manufacturing a solar cell module according to any one of claims 1 to 9, wherein the laminated body is compressed in the plate thickness direction by using a diaphragm via a cushioning material. The vacuum laminator device has another heating plate arranged on the upper side of the laminate in a pressure reducing tank in which the laminate is arranged, and the laminate is heated from both the upper and lower surfaces thereof via a cushioning material. The method for manufacturing a solar cell module according to claim 10. The method for manufacturing a solar cell module according to any one of claims 1 to 11, wherein the solar cell element comprises a crystalline solar cell, an amorphous solar cell, an organic thin-film solar cell, or a CIGS solar cell.

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