JP2016152321A - Encapsulation material sheet and solar cell module including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell encapsulation material sheet that never generate poor appearance regardless of heating and pressurizing conditions in a manufacturing process and a solar cell module including the same.SOLUTION: The encapsulation material sheet is used by being disposed on a non-light-receiving surface side of a solar cell element of a solar cell module. The encapsulation material sheet has a configuration of having at least two layers and including pigments.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sealing material sheet.

  A solar cell module has a sealing material sheet laminated on both sides of a solar cell element made of a semiconductor wafer such as single crystal silicon or polycrystalline silicon, and protective members such as glass and a back sheet are provided on the upper and lower surfaces of the sealing material sheet. Superposed and laminated integrated are used.

  For the purpose of improving the power generation efficiency of solar cells, it is required to concentrate incident light on the power generation element as efficiently as possible. Only the non-light-receiving surface side sealing material of the solar cell module is colored white and sealed white Sunlight is reflected by a material, and reflected light is incident on a solar cell element. (For example, Patent Documents 1 and 2)

Japanese Patent Laid-Open No. 6-177412 Japanese Patent Laying-Open No. 2005-050928

  However, in the sealing material described in Patent Documents 1 and 2, depending on the heating and pressing conditions in the manufacturing process, the white sealing material is formed between the solar cell element and the light-receiving surface side sealing material in the process of stacking and integrating the solar cell modules. In some cases, the power generation efficiency may be reduced or the appearance may be deteriorated.

  In view of the problems of the prior art as described above, in the present invention, a solar cell encapsulant sheet that does not cause poor appearance regardless of the heating and pressing conditions in the production process, and a solar cell module using the encapsulant sheet are provided. The purpose is to provide.

  The present inventors have intensively studied to achieve the above object, and have found that the above problem can be solved by adopting the following configuration.

  That is, the encapsulant sheet according to the present invention is as follows.

  A sealing material sheet used by being disposed on the non-light-receiving surface side of a solar cell element of a solar cell module, wherein the sealing material sheet has at least two layers and includes a pigment. Sealing material sheet.

  ADVANTAGE OF THE INVENTION According to this invention, the solar cell sealing material sheet which reduced the surroundings of the back surface side sealing material, this sealing material sheet, and a solar cell module can be provided.

It is a schematic diagram of the cross section of the sealing material sheet of this invention. It is a schematic diagram of the cross section of the solar cell module which uses the sealing material sheet of this invention.

  A sealing material sheet used by being disposed on a non-light-receiving surface side of a solar cell element of a solar cell module, wherein the sealing material sheet has at least two layers and includes a white pigment. , A sealing material sheet, and a solar cell module.

  Below, the sealing material sheet of this invention and a solar cell module are demonstrated.

<Sealing material sheet>
FIG. 1 is a schematic cross-sectional view of an example of the sealing material sheet of the present invention. As illustrated, in a preferred embodiment of the encapsulant sheet 10 of the present invention, each layer such as the A layer and the B layer of the encapsulant sheet of the present invention is configured to have two layers, an A layer 11 and a B layer 12. The resin constituting the resin is ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid aliphatic ester copolymer, ethylene-glycidyl methacrylate copolymer, ethylene-glycidyl methacrylate- (meth) acrylic acid aliphatic ester copolymer. Polymer, and ethylene-polar monomer copolymer such as ethylene-glycidyl methacrylate-vinyl acetate copolymer, acid-modified resin, maleic anhydride-modified resin, silane-modified resin, terpene resin, saponified ethylene-vinyl acetate copolymer , Polyvinyl alcohol, polyvinyl butyral, ionomer resin, urethane resin, epoxy resin, terpene tree It is a homopolymer of ethylene such as fat, petroleum resin, high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, and ultra low density polyethylene, or a copolymer of ethylene and α-olefin. Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene and the like. From the viewpoint of being inexpensive, highly transparent, and excellent in flexibility, an ethylene-vinyl acetate copolymer, an ethylene- (meth) acrylic acid aliphatic ester copolymer, an ethylene-glycidyl methacrylate copolymer, an ethylene-glycidyl A resin containing an ethylene-polar monomer copolymer selected from a methacrylate- (meth) acrylic acid aliphatic ester copolymer and an ethylene-glycidyl methacrylate-vinyl acetate copolymer is more preferable. The resins constituting the A layer and the B layer may be the same or different. In particular, both the A layer and the B layer preferably have an ethylene-polar monomer copolymer as a main component. Here, the main component means a component that is contained most on a mass basis in all the components of the layer.

  The encapsulant sheet of the present invention has at least two layers. In the present invention, it is important that any layer contains a pigment. And as for the sealing material sheet of this invention, it is preferable that any layer contains a white pigment as a pigment, and also it is preferable that A layer or B layer contains a white pigment. When the encapsulant sheet contains a white pigment, light that has passed through the light-receiving surface protective base material 30 and the light-receiving surface-side encapsulant 20 and has not been directly absorbed by the cell when the module is formed is a non-light-receiving surface side. The amount of power generation can be increased by hitting the sealing material sheet 10 and reflecting the light at a portion closer to the cell of the non-light-receiving surface side sealing material sheet 10. Suitable white pigments include titanium oxide and calcium carbonate that can reflect light in a wide wavelength range.

  When the outermost layer on the side in contact with the non-light-receiving surface side of the solar cell element is an A layer, the A layer preferably contains no pigment, or preferably contains 1% by mass or less of the pigment in 100% by mass of the entire A layer. When the content of the pigment in the layer A exceeds 1% by mass, the wraparound of the pigment occurs on the solar cell element in the stacking integration step, and the power generation amount is reduced.

  When the outermost layer on the side in contact with the non-light-receiving surface side of the solar cell element is the A layer and the other outermost layer is the B layer, the content of the pigment in the B layer is based on 100 parts by mass of the resin in the B layer. The amount is preferably 1 part by mass or more and 10 parts by mass or less, more preferably 2 parts by mass or more and 6 parts by mass or less. When the pigment content is less than 2 parts by mass, the reflectance is low and the contribution of improving the power generation efficiency is small. Moreover, when content exceeds 6 mass parts, resin will become weak and film forming property will fall.

  In the present invention, the A layer and the B layer preferably contain an organic oxide in order to improve mechanical strength and heat resistance. Although it does not specifically limit as an organic peroxide, It selects in consideration of the temperature at the time of manufacturing a sealing material sheet, the heating at the time of creating a solar cell module, the bonding temperature, storage stability, etc. In particular, organic peroxides having a decomposition temperature of 70 ° C. or more with a half-life of 10 hours are preferable. Examples of such organic peroxides include dicumyl peroxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-bis (t-butylperoxy ) Hexane, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane-3-di-t-butyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, 2, 5-Dimethyl-2,5-di (t-butylperoxy) hexane, α, α′-bis (t-butylperoxyisopropyl) benzene, n-butyl-4,4-bis (t-butylperoxy) Valerate, 2,2-bis (t-butylperoxy) butane, 1,1-bis (t-butylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) -3,3 5-trimethylcyclohexane, t-butylperoxybenzoate, benzoyl peroxide, t-butylperoxyacetate, methyl ethyl ketone peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) -3,3 5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, methyl ethyl ketone peroxide, 2,5-dimethylhexyl-2,5-bisperoxybenzoate, t-butyl hydroperoxide, p-menthane hydro Peroxide, p-chlorobenzoyl peroxide, hydroxyheptyl peroxide, chlorohexanone peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, cumyl peroxide Kutoate, succinic acid peroxide, t-butylperoxymaleic acid, acetyl peroxide, t-butylperoxy (2-ethylhexanoate), m-toluoyl peroxide, t-butylperoxyisobutyreo, 2 , 4-dichlorobenzoyl peroxide, t-butylperoxyisopropyl carbonate, t-butylperoxy-2-ethylhexyl carbonate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxy Examples thereof include isononanoate, t-butyl peroxybenzoate, 1,1-bis (t-amylperoxy) cyclohexane, ethyl-3,3-di (t-butylperoxy) butyrate. These organic peroxides may be contained in combination of two or more.

  These organic peroxides are preferably 0.1 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, and particularly preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of the resin. . If the content of the organic peroxide is less than 0.1 parts by mass with respect to 100 parts by mass of the resin, the resin may not be crosslinked. In addition to the low effect, undecomposed organic peroxide may remain in the encapsulant sheet and cause deterioration over time.

  The A layer and the B layer preferably further contain a crosslinking aid. Here, the crosslinking aid means a polyfunctional monomer having a plurality of unsaturated bonds in the molecule. A polyfunctional monomer having a plurality of unsaturated bonds in the molecule reacts with an active radical compound generated by the decomposition of an organic peroxide to uniformly and efficiently crosslink the ethylene-vinyl acetate copolymer. it can. Examples of these crosslinking aids include triallyl isocyanurate, triallyl cyanurate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tris [(meth) acryloyloxyethyl] isocyanurate, Dimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol ethoxytetra (meth) acrylate, dipentaerystol penta (meth) acrylate, dipentaerystol hexa (meth) acrylate, divinylbenzene, etc. Can be mentioned. These crosslinking aids may be used alone or in combination of two or more.

  More preferably, the A layer and the B layer further contain an ultraviolet absorber. The UV absorber absorbs harmful UV rays in the irradiated light and converts them into innocuous heat energy within the molecule, preventing the active species that initiate photodegradation in the polymer from being excited. . Known ultraviolet absorbers can be used. For example, benzophenone series, benzotriazole series, triazine series, salicylic acid series, cyanoacrylate series, etc. can be used. One of these may be used, or two or more may be used in combination.

  Among these ultraviolet absorbers, benzophenone-based ultraviolet absorbers are most preferable from the viewpoints of the ultraviolet absorption effect and coloring of the ultraviolet absorber itself.

  As for content of the ultraviolet absorber in A layer and B layer, 0.1-3 mass parts is preferable with respect to 100 mass parts of resin, More preferably, it is 0.1-2.0 mass parts. When the content of the ultraviolet absorber in the A layer is less than 0.1 parts by mass, the content effect is low, and it is not preferable.

  The A layer and the B layer preferably contain a light stabilizer. The light stabilizer traps radical species that are harmful to the polymer and prevents the generation of new radicals. As the light stabilizer, a hindered amine light stabilizer is preferably used.

  As a hindered amine light stabilizer, bis (2,2,6,6-tetramethyl-1 (octyloxy) -4-piperidinyl) ester, 1,1-dimethylethyl hydroperoxide and octane produced by reaction with decanedioic acid 70% by mass of a product and 30% by mass of polypropylene, bis (1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxy Phenyl] methyl] butyl malonate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and methyl-1,2,2,6,6-pentamethyl-4-piperidylsebacate mixture Can be mentioned. The above-mentioned hindered amine light stabilizers may be used alone or in combination of two or more.

  Among these, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and methyl-1,2,2,6,6-pentamethyl-4-piperidyl seba are used as hindered amine light stabilizers. It is preferred to use a mixture of ketates, as well as methyl-4-piperidyl sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate. Moreover, it is preferable to use a hindered amine light stabilizer having a melting point of 60 ° C. or higher.

  The content of the hindered amine light stabilizer in the A layer and the B layer is preferably 0.1 to 3.0 parts by mass, more preferably 0.1 to 2.0 parts by mass with respect to 100 parts by mass of the resin. Part by mass. If the content of the hindered amine light stabilizer in the A layer is less than 0.1 parts by mass, the stabilizing effect is insufficient, and even if the content exceeds 3.0 parts by mass, it is a cause of coloring and cost increase. It only becomes.

  In addition, the A layer and the B layer contain, as necessary, antioxidants, flame retardants, flame retardant aids, plasticizers, lubricants, and the like as known additives within a range that does not impair the effects of the present invention. You may do it.

  The thickness of the A layer is preferably 0.01 mm or more and 0.30 mm or less, and more preferably 0.05 mm or more and 0.20 mm or less. If the thickness of the A layer is less than 0.01 mm, the white pigment in the B layer wraps around the solar cell element in the stacking and integration step, resulting in a decrease in the amount of power generation. On the other hand, if the thickness of the A layer exceeds 0.30 mm, the reflectivity is lowered and the power generation amount is not improved.

  The thickness of the B layer is preferably 0.10 mm or more and 0.50 mm or less, and more preferably 0.2 mm or more and 0.4 mm or less. When the thickness of the B layer is less than 0.10 mm, the reflectivity is lowered and the power generation amount is not improved. On the other hand, if the thickness of the B layer exceeds 0.5 mm, the cost increases and the weight per solar cell module increases.

  Next, the film forming method of the sealing material sheet of the present invention will be described.

  The sealing material sheet of the present invention can be laminated in a desired multilayer by a known molding method using a T-die extruder, a calendar molding machine, an inflation molding machine or the like, or a sheet of each layer is separately molded, It can also be manufactured by stacking. That is, the method for laminating the sealing material sheet may be a known so-called multilayer molding, or may be an extrusion laminating method in which each layer is molded by a separate molding machine and then laminated.

  Moreover, it is preferable that the sealing material sheet of the present invention is embossed on one side or both sides from the viewpoints of handling at the time of solar cell module creation and air leakage. A known method is used for embossing. For example, a method of embossing with a forming roll immediately after being extruded from a T die or the like, and a method of embossing after reheating a sheet extruded from a T die or the like can be mentioned.

<Solar cell module>
The solar cell module of the present invention includes a transparent protective member, a light-receiving surface side sealing material sheet, a solar cell element, so that the A layer of the sealing material sheet faces the solar cell element side, and the B layer faces the back surface protective member side. It is a solar cell module obtained by arrange | positioning and laminating the non-light-receiving surface side sealing material sheet of Claim 6, and a back surface protection member in this order. Hereinafter, the solar cell module of the present invention will be described below.

  A solar cell module 60 shown in FIG. 2 includes a transparent protective member 30 fixed by a light-receiving surface side sealing material sheet 20 and a back surface protection member 50 fixed by a back surface-side sealing material sheet 10, and includes a light-receiving surface side sealing. The solar cell element 40 is disposed between the material sheet 20 and the back surface side sealing material sheet 10 with the light receiving surface side of the solar cell element 40 facing the transparent member 20 side.

  The solar cell module 60 of the present invention obtained by using the non-light-receiving surface side sealing material sheet 10 of the present invention is manufactured as follows.

  The solar cell element 40 has a light receiving surface side sealing material sheet 20 on the non-light receiving surface side, and the non-light receiving surface side sealing material sheet 10 has an A layer 11 on the solar cell element 40 side, a back surface side sealing material sheet. The laminated body which arrange | positions so that 10 B layer 12 may become the back surface protection member 50 side, and arrange | positions the light-receiving surface protection member 30 and the back surface protection member 50 is created.

Next, the laminate is heated with a vacuum laminator or the like at a temperature of 130 to 180 ° C. and a deaeration time of 2 to 15 minutes, and subsequently at a press pressure of 0.1 to 1.5 kg / cm ² and a press time of 8 to 45 minutes. The solar cell module of this invention obtained using the sealing material sheet | seat of this invention can be manufactured by heat-pressing pressure bonding. The heating temperature and time can be appropriately changed according to the composition and thickness of the encapsulant sheet.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to a following example.

[Characteristic evaluation method]
The thickness of each layer:
From the non-light-receiving surface side encapsulant sheet prepared by the method described below, 5 points in the width direction were evenly selected and cut at each point with a razor blade FAS-10 manufactured by Feather Safety Shaving Co., Ltd. ( Observation was performed using a laser microscope VKX-100 manufactured by Keyence Co., Ltd., and the thickness of the layer was directly read, and an average of 5 points was defined as the thickness of each layer.

Average reflectance The non-light-receiving surface side sealing material sheet produced by the method shown below was measured for an average reflectance of 400 nm to 1200 nm using an ultraviolet-visible near-infrared spectrophotometer UV-3600 manufactured by Shimadzu Corporation.
Amount of wraparound of B layer resin onto solar cell element For the solar cell module produced by the method shown below, the amount of B layer resin (non-light-receiving surface sealing material sheet 11) wrapping around the solar cell element is (stock) ) When observed using Keyence laser microscope VKX-100, ○ when the maximum wraparound amount is less than 1 mm from the end of the solar cell element, △ when 3 mm or more and △ when 3 mm or more As evaluated.

Example 1
A two-layer coextrusion device is prepared in which two extruders are connected to a single T die via a feed block. For forming the A layer, one of these two machines is equipped with ethylene-acetic acid. 100 parts by mass of vinyl copolymer (vinyl acetate content 28% by mass, melting point 71 ° C.), 0.5 part by mass of 2,5-dimethyl-2,5-di (t-butylperoxy) hexane as a crosslinking agent , 0.2 part by mass of γ-methacryloxypropyltrimethoxysilane as a silane coupling agent for improving adhesion to a glass substrate, and 2,2′-dihydroxy-4,4′-di (hydroxy) as an ultraviolet absorber A resin composition comprising 0.1 part by weight of methyl) benzophenone and 0.3 part by weight of bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate as a light stabilizer was supplied.

  Another machine for forming the B layer is 100 parts by mass of an ethylene-vinyl acetate copolymer (vinyl acetate content 28% by mass, melting point 71 ° C.) and 2,5-dimethyl-2,5-diethylene as a crosslinking agent. 0.5 parts by mass of (t-butylperoxy) hexane, 0.2 parts by mass of γ-methacryloxypropyltrimethoxysilane as a silane coupling agent for improving adhesion to a glass substrate, 2 as an ultraviolet absorber , 2′-dihydroxy-4,4′-di (hydroxymethyl) benzophenone, 0.1 parts by weight of bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate as a light stabilizer 0.3 A resin composition consisting of 3 parts by mass and 3 parts by mass of titanium dioxide was supplied.

Next, the resin composition is melt-kneaded at 100 ° C. in each of the two extruders, the molten resin composition is supplied to the feed block, and the sheet of the A layer is formed from the T die arranged at the tip of the feed block. The sealing material sheet 10 was formed by coextrusion so that the thickness was 0.05 mm and the thickness of the B layer was 0.40 mm.
Moreover, it adjusted so that it might become the composition similar to the said A layer, and produced the surface side sealing material sheet 20 so that thickness might be set to 0.45 mm.

  Using the obtained back surface side sealing material and front surface side sealing material, a light receiving surface protective material made of a 3.2 mm thick glass plate, a front surface side sealing material, a silicon power generation element, a back surface side sealing material, a thickness A 38 μm polyfluorinated ethylene film was laminated in this order. A solar cell module was manufactured by thermocompression bonding with a vacuum laminator at a temperature of 135 ° C., a degassing time of 8 minutes, a pressing time of 1 minute, and a holding time of 15 minutes.

(Example 2)
A sealing material sheet was produced in the same manner as in Example 1 except that the thickness of the A layer was 0.10 mm.

(Example 3)
A sealing material sheet was produced in the same manner as in Example 1 except that the thickness of the A layer was 0.30 mm.

Example 4
A sealing material sheet was produced in the same manner as in Example 3 except that the titanium dioxide content in the A layer was 0.5 parts by mass with respect to 100 parts by mass of the ethylene-vinyl acetate copolymer.

(Example 5)
A sealing material sheet was produced in the same manner as in Example 3 except that the titanium dioxide content in the A layer was 1.0 part by mass with respect to 100 parts by mass of the ethylene-vinyl acetate copolymer.

(Comparative Example 1)
A sealing material sheet was produced in the same manner as in Example 1 except that the thickness of the A layer was 0.40 mm.

(Comparative Example 2)
The thickness of the B layer was 0.40 mm, and a single-layer encapsulant sheet having the same composition as that of Comparative Example 1 was produced.

(Comparative Example 3)
The thickness of the A layer was 0.40 mm, and a single-layer sealing material sheet having a titanium dioxide composition equivalent to that in Example 1 was produced.
(Comparative Example 4)
A monolayer encapsulant sheet was prepared without containing titanium dioxide in layer A and having a thickness of 0.40 mm.

  The wraparound evaluation of the colored sealing material on the cells of the produced solar cell module confirmed the amount of wraparound of the colored resin.

<Evaluation method of backside sealing material on cell>
About the produced solar cell module <Measurement method of reflectance>
The reflectance of the non-light-receiving surface side sealing material of the produced solar cell was measured using a spectrophotometer U-4100.
The obtained results are shown in Table 1.

  As is clear from the results shown in Table 1, when the sealing material sheet of the present invention is used (Example), it shows a high average reflectance and suppresses the amount of wraparound of the colored resin onto the solar cell element. It had been.

  According to the present invention, a solar cell module with good appearance and high power generation efficiency can be easily provided.

DESCRIPTION OF SYMBOLS 10 Non-light-receiving surface side sealing material sheet 11 A layer 12 B layer 20 Light-receiving surface side sealing material sheet 30 Transparent protection member 40 Solar cell element 50 Back surface protection member 60 Solar cell module

Claims (7)

A sealing material sheet used by being disposed on the non-light-receiving surface side of the solar cell element of the solar cell module,
The encapsulant sheet has at least two layers,
An encapsulant sheet comprising a pigment.   The encapsulant sheet according to claim 1, wherein the pigment is a white pigment. When the outermost layer on the side in contact with the non-light-receiving surface side of the solar cell element is A layer,
The encapsulant sheet according to claim 1, wherein the A layer does not contain a pigment or contains 1% by mass or less of the pigment in 100% by mass of the entire A layer.   The said A layer is 0.01 mm or more and 0.30 mm or less, The sealing material sheet of Claim 3 characterized by the above-mentioned.   The encapsulant sheet according to claim 3 or 4, wherein the A layer contains an ethylene-polar monomer copolymer as a main component. The encapsulant sheet has a two-layer configuration,
When the outermost layer on the side in contact with the non-light-receiving surface side of the solar cell element is an A layer and the other outermost layer is a B layer, the B layer is mainly composed of an ethylene-polar monomer copolymer. The sealing material sheet according to any one of claims 1 to 5.   The non-light receiving device according to claim 6, wherein the A layer of the encapsulant sheet faces the solar cell element side and the B layer faces the back surface protective member side, the transparent protective member, the light receiving surface side encapsulant sheet, the solar cell element. The solar cell module obtained by arrange | positioning and laminating a surface side sealing material sheet and a back surface protection member in this order.

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