JP2011014725A - Wavelength conversion-type solar cell sealing material, solar cell module employing the same, and methods for manufacturing these - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength conversion-type solar cell sealing material that can enhance efficiency of using light, by reducing sunlight loss caused by spectrum mismatching to bring a configuration having a higher visible light transmittance, thus improving efficiency of power generation, to provide a solar cell module employing this, and to provide a method of manufacturing these.SOLUTION: The wavelength conversion-type solar cell sealing material includes a fluorescent material that is used as one of the optically-transparent layers for a solar cell module having two or more optically-transparent layers and solar cells, wherein the fluorescent material is so made as to have a covered fluorescent material object having fluorescent material particles and a covering layer using a material with a refraction factor lower than that of the fluorescent material particles, which covers the perimeter of the fluorescent material particles, and the covered fluorescent material object is constructed such that it is dispersed by the transparent sealing resin.

Description

  The present invention relates to a wavelength conversion type solar cell encapsulant for a solar cell, a solar cell module using the same, and a manufacturing method thereof. More specifically, a solar cell module capable of increasing power generation efficiency by converting light in a wavelength region that does not contribute to power generation into light in a wavelength region that contributes to power generation, a wavelength conversion type solar cell sealing material used therefor, and these It is related with the manufacturing method.

  A conventional silicon crystal solar cell module has the following configuration. The protective glass on the surface (also referred to as cover glass) is made of tempered glass with a focus on impact resistance, and is in close contact with the sealing material (usually referred to as a resin or filler mainly composed of ethylene vinyl acetate copolymer). In order to improve the properties, one side has an uneven pattern by embossing.

Moreover, the uneven | corrugated pattern is formed inside, and the surface of a solar cell module is smooth. Moreover, the sealing material and back film for carrying out protection sealing of the photovoltaic cell and a tab wire are provided under the protective glass (for example, refer nonpatent literature 1).
A layer that emits light in a wavelength region that can contribute to power generation by converting the wavelength of light in the ultraviolet region or infrared region that does not contribute to power generation in a sunlight spectrum using a fluorescent substance (also referred to as a light emitting material) Many methods for providing the battery on the light-receiving surface side have been proposed (see, for example, Patent Documents 2 to 17).

In addition, a method for incorporating a rare earth complex, which is a fluorescent substance, in a sealing material has been proposed (see, for example, Patent Document 18).
Conventionally, ethylene-vinyl acetate copolymers imparted with thermosetting properties have been widely used as transparent sealing materials for solar cells (see, for example, Patent Documents 19 to 26).

JP 2005-101513 A JP 2000-328053 A JP 09-230396 A JP 2003-243682 A JP 2003-218379 A JP 11-345993 A JP 2006-024716 A Japanese Patent Publication No. 08-004147 JP 2001-094128 A JP 2001-352091 A Japanese Patent Laid-Open No. 10-261811 Japanese Patent No. 2660705 JP 2006-269373 A JP 63-006881 A JP 2008-195664 A JP 2007-230955 A JP 2006-298974 A JP 2006-303033 A JP 2003-51605 A JP 2005-126708 A JP-A-8-283696 JP-A-6-322334 JP 2008-205448 A JP 2008-118073 A JP 2008-159856 A JP 2000-183385 A

Yasuhiro Sasakawa, “Solar Power Generation”-Latest Technology and System, 2000, CMC Corporation Hiroshi Toyoda; “Non-reflective periodic structure”, Optics, Vol. 32, No. 8, p. 489 (2003)

  Patents 2 to 14 propose a wavelength conversion of light that does not contribute to power generation into light in a wavelength range that can contribute to power generation. The wavelength conversion layer contains a fluorescent material, but this fluorescent material is generally used. When the incident sunlight passes through the wavelength conversion film, it is scattered and does not reach the solar cells sufficiently, and the ratio of not contributing to power generation increases. As a result, there is a problem that even if the light in the ultraviolet region is converted into the light in the visible region by the wavelength conversion layer, the ratio of the electric power generated with respect to the incident sunlight (power generation efficiency) is not so high.

  In addition, the method described in Patent Document 15 is easily hydrolyzed together with a rare earth complex and ethylene vinyl acetate (EVA) widely used as a sealing material, and not only deteriorates but also converts wavelength-converted light. It is difficult to introduce into solar cells.

  The present invention is intended to improve the above-described problems, and it is an object of the present invention to improve light utilization efficiency in a solar cell module and stably improve power generation efficiency. For example, in a silicon crystal solar cell, light having a wavelength shorter than 400 nm in sunlight is not effectively used, and approximately 56% of sunlight energy is used for photovoltaic power generation due to this spectrum mismatch. Does not contribute. The present invention uses a fluorescent material having a specific shape with excellent moisture resistance and heat resistance, good dispersibility, and suppressed concentration quenching, wavelength conversion, and efficient and stable use of sunlight. It is to overcome the mismatch.

  That is, the wavelength conversion type solar cell encapsulant of the present invention is intended to contain a fluorescent material that is excellent in moisture resistance and heat resistance, has good dispersibility, and does not cause concentration quenching. Further, the wavelength conversion type solar cell encapsulant of the present invention converts the light that does not contribute to solar power generation into the wavelength that contributes to power generation in the incident sunlight, and at the same time, without scattering the light, The purpose is to introduce it efficiently into the cell.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have fluorescent substance particles and a coating layer covering the periphery of the fluorescent substance with a specific substance having a refractive index lower than that of the fluorescent substance particles. By using the coated phosphor material for the wavelength conversion type solar cell encapsulant, the light that does not contribute to solar power generation in the incident sunlight is converted to the wavelength that contributes to power generation, and at the same time, the moisture resistance and heat resistance are improved. It has been found that it can be efficiently introduced into a solar battery cell without scattering of fluorescent material by excellent and dispersibility and incident sunlight, and the present invention has been completed. Furthermore, the resistance of the rare earth metal organic complex to humidity can be increased by this coating.

That is, the present invention is as follows.
(1) In a wavelength conversion type solar cell encapsulant containing a fluorescent material, which is used as one of the light transmissive layers of a solar cell module having a plurality of light transmissive layers and solar cells,
The fluorescent material is a coated fluorescent material body having fluorescent material particles and a coating layer covering the periphery of the fluorescent material particles with a material having a lower refractive index than the fluorescent material particles,
A wavelength conversion type solar cell encapsulant in which the coated phosphor material is dispersed in a transparent encapsulating resin.

(2) The wavelength-converting solar cell encapsulating material according to (1), wherein the coated fluorescent substance body is dispersed or mixed in the transparent encapsulating resin at 0.1 to 10 mass percent. .
(3) The wavelength-converting solar cell encapsulating as described in (1) or (2) above, wherein the substance having a lower refractive index than the fluorescent substance is a silica-based material formed by a sol-gel method Wood.

(4) Any one of the above (1) to (3), wherein the wavelength conversion type solar cell encapsulant has a multilayer structure, and at least one of the layers has a wavelength conversion function. The wavelength conversion type solar cell sealing material described in 1.
(5) The wavelength conversion type solar cell encapsulating material is disposed on the light receiving surface of the solar cell, and the plurality of light transmissive layers are layered from the light incident side, layer 1, layer 2,. Any one of the above (1) to (4), wherein n1 ≦ n2 ≦... ≦ nm holds when the layer m is set and the refractive indexes thereof are n1, n2,. The wavelength conversion type solar cell sealing material according to any one of the above.

(6) The wavelength conversion type solar cell encapsulating material according to any one of (1) to (5), wherein the fluorescent material is a europium complex.
(7) A solar cell module having the wavelength conversion type solar cell sealing material according to any one of (1) to (6) above.

(8) A phosphor particle coating step of coating phosphor particles with a silica-based material by a sol-gel reaction using silicon alkoxide to obtain a coated phosphor body having a coating layer;
The coated phosphor material body is mixed or dispersed in a transparent encapsulating resin to produce a resin composition, and the resin composition is used to form a wavelength conversion type solar cell encapsulant into a sheet form, The manufacturing method of the wavelength conversion type solar cell sealing material as described in any one of said (1)-(6) which has.

(9) In the method for producing a solar cell module having a plurality of light transmissive layers and solar cells, the wavelength conversion type solar cell encapsulating material according to any one of (1) to (6) above is laminated. And the manufacturing method of the solar cell module characterized by having the process of comprising one of the said light transmissive layers.

  According to the present invention, when applied to a solar cell module, light that does not contribute to solar power generation is converted into a wavelength that contributes to power generation, and at the same time, sunlight is efficiently scattered without being scattered. And the wavelength conversion type solar cell sealing material which can utilize sunlight stably can be provided.

<Wavelength conversion solar cell encapsulant and method for producing the same>
The wavelength conversion type solar cell encapsulant of the present invention is used as one of the light transmissive layers of a solar cell module having a plurality of light transmissive layers and solar cells, and includes a fluorescent material, A fluorescent substance particle, and a coating fluorescent substance that covers the periphery of the fluorescent substance particle with a substance having a refractive index lower than that of the fluorescent substance particle (hereinafter also referred to as “low refractive index coating material”). It is characterized by being a body, and is further disperse | distributing in transparent sealing resin. By reducing the refractive index of the coated phosphor material, the scattering loss of sunlight can be reduced.

  Here, the coated phosphor material is specifically a material in which phosphor particles are encapsulated with sol-gel glass, and the properties thereof are fluorescent even when solid particles are dispersed in a transparent encapsulating resin. It may be a liquid in which the fine particle colloid of the substance is dispersed.

  The refractive index of the phosphor particles is a value unique to the material, and it is difficult to achieve both high luminous efficiency and low refractive index. Therefore, by covering the periphery of the phosphor particles with a layer of a specific substance (low refractive index coating material) having a lower refractive index than that of the phosphor particles, the scattering loss of sunlight due to Rayleigh scattering can be reduced. I can do it.

It is more preferable that the low refractive index coating material has a lower refractive index than that of the phosphor particles and has a smaller difference from the refractive index of the transparent sealing resin.
In general, the refractive index of the phosphor particles is higher than 1.5. Therefore, a material having a refractive index of 1.4 to 1.5 may be used as the low refractive index coating material. By doing so, the refractive index of a covering fluorescent substance body will also be 1.4-1.5. Such a low refractive index coating material will be described later.

  By coating the phosphor particles with a specific low refractive index coating material, the moisture resistance and heat resistance of the phosphor particles are improved, the dispersibility is good and the concentration quenching is suppressed, and the refraction of the coated phosphor body is also improved. The rate can be reduced, thereby reducing the scattering loss of sunlight.

  Here, the relationship between the particle diameter of the coated phosphor material and the refractive index of the coating layer in Rayleigh scattering of the coated phosphor material (scattering of light by particles having a size smaller than the wavelength of light) is shown in the following equation.

As can be seen from the above equation, the scattering can be reduced by lowering the refractive index of the low refractive index coating material.
It can also be seen from the above formula that the loss of sunlight due to scattering can be reduced by reducing the particle size of the coated phosphor material.

  The scattering of light correlates with the coating phosphor material in the encapsulant, that is, the difference in refractive index between the coating layer and the transparent sealing resin, and the size of the particle size of the coating phosphor material. Specifically, if the difference between the refractive index of the coating layer and the refractive index of the transparent sealing resin is small, the light scattering is not significantly affected by the particle diameter of the coated phosphor material, and the light scattering is also small. It will be a thing. However, if the difference between the refractive index of the coating layer and the refractive index of the transparent sealing resin increases, light scattering is affected by the size of the particle diameter of the coated phosphor material, so that the smallest possible particles The diameter is preferred.

  In order to sufficiently reduce the scattering loss due to Rayleigh scattering, the size of the particles (primary particle diameter) of the coated phosphor material coated with the low refractive index coating material used for the wavelength conversion type solar cell encapsulant of the present invention It is desirable that it is 1/4 or less of the wavelength of light. That is, since the light in the ultraviolet region is about 400 nm, the primary particle size of the coated phosphor is required to be 100 nm or less.

  In the present invention, it is desirable that the low refractive index coating material used for the wavelength conversion type solar cell encapsulant is a silica-based material formed on the surface of the phosphor particles by a sol-gel method using silicon alkoxide. By using the sol-gel method, it is possible to form a coated phosphor material at a low temperature and with a simple process (because glass sealing is low temperature, it is possible to form a film in a solution or by drying it), so the wavelength is low. A conversion type solar cell encapsulant can be produced.

  Since the silica-based material has a lower refractive index than that of the phosphor particles, a wavelength conversion type solar cell encapsulant produced using the silica material can reduce light scattering loss. Further, among the fluorescent substance particles, the rare earth metal organic complex used in the present invention is generally deteriorated by oxygen or moisture, and there is a problem that the wavelength conversion efficiency deteriorates with time. Therefore, by covering the periphery of the phosphor particles with a silica-based material as a low refractive index coating material, the silica-based material blocks oxygen and moisture and prevents the wavelength conversion efficiency of the phosphor particles from deteriorating. can get.

  The method of coating the phosphor particles with the silica-based material by the sol-gel method is not particularly limited as long as it is a known method, but is performed by treating the phosphor particles with a silicon alkoxide in a solvent and heating. Can do.

  Examples of the silicon alkoxide used in the sol-gel method include tetraalkoxysilane, trialkoxysilane, and diorganodialkoxysilane.

  Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-iso-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, and tetra-tert-butoxysilane. And tetraphenoxysilane.

Moreover, the compound like following formula (1) by which the alkoxy group was substituted by the alkyl group may be sufficient.
R ¹ _n SiX _4-n (1)
(In the above formula, R ¹ represents an H atom or an organic group having 1 to 20 carbon atoms, X represents a hydrolyzable group, n represents an integer of 0 to 2, and when n is 2, R ¹ may be the same or different, and when n is 0 to 2, each X may be the same or different.)
Examples of the organic group having 1 to 20 carbon atoms include linear or branched alkyl groups having 1 to 20 carbon atoms. Moreover, hydrogen of the alkyl group may be substituted with a group containing fluorine, Si atom, or the like.
Moreover, as a hydrolysable group, a C1-C20 alkoxy group is mentioned.

  Examples of the trialkoxysilane include trimethoxysilane, triethoxysilane, tripropoxysilane, fluorotrimethoxysilane, fluorotriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltri-n-propoxysilane, and methyltri-iso. -Propoxysilane, methyltri-n-butoxysilane, methyltri-iso-butoxysilane, methyltri-tert-butoxysilane, methyltriphenoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltri-n-propoxysilane, ethyltri-iso -Propoxysilane, ethyltri-n-butoxysilane, ethyltri-iso-butoxysilane, ethyltri-tert-butoxysilane, ethyltriphenoxy N-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltri-n-propoxysilane, n-propyltri-iso-propoxysilane, n-propyltri-n-butoxysilane, n-propyltri -Iso-butoxysilane, n-propyltri-tert-butoxysilane, n-propyltriphenoxysilane, iso-propyltrimethoxysilane, iso-propyltriethoxysilane, iso-propyltri-n-propoxysilane, iso-propyl Tri-iso-propoxysilane, iso-propyltri-n-butoxysilane, iso-propyltri-iso-butoxysilane, iso-propyltri-tert-butoxysilane, iso-propyltriphenoxysilane, n-butyltrimethyl Xylsilane, n-butyltriethoxysilane, n-butyltri-n-propoxysilane, n-butyltri-iso-propoxysilane, n-butyltri-n-butoxysilane, n-butyltri-iso-butoxysilane, n-butyltri-tert -Butoxysilane, n-butyltriphenoxysilane, sec-butyltrimethoxysilane, sec-butyltriethoxysilane, sec-butyltri-n-propoxysilane, sec-butyltri-iso-propoxysilane, sec-butyltri-n-butoxy Silane, sec-butyltri-iso-butoxysilane, sec-butyltri-tert-butoxysilane, sec-butyltriphenoxysilane, t-butyltrimethoxysilane, t-butyltriethoxysilane, t-butylto Ri-n-propoxysilane, t-butyltri-iso-propoxysilane, t-butyltri-n-butoxysilane, t-butyltri-iso-butoxysilane, t-butyltri-tert-butoxysilane, t-butyltriphenoxysilane, Phenyltrimethoxysilane, phenyltriethoxysilane, phenyltri-n-propoxysilane, phenyltri-iso-propoxysilane, phenyltri-n-butoxysilane, phenyltri-iso-butoxysilane, phenyltri-tert-butoxysilane, Phenyltriphenoxysilane, trifluoromethyltrimethoxysilane, pentafluoroethyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxy Run, and the like.

  Examples of the diorganodialkoxysilane include dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldi-n-propoxysilane, dimethyldi-iso-propoxysilane, dimethyldi-n-butoxysilane, dimethyldi-sec-butoxysilane, and dimethyldi-tert. -Butoxysilane, dimethyldiphenoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldi-n-propoxysilane, diethyldi-iso-propoxysilane, diethyldi-n-butoxysilane, diethyldi-sec-butoxysilane, diethyldi-tert- Butoxysilane, diethyldiphenoxysilane, di-n-propyldimethoxysilane, di-n-propyldiethoxysilane, di-n-propyldi-n-propoxy Di-n-propyldi-iso-propoxysilane, di-n-propyldi-n-butoxysilane, di-n-propyldi-sec-butoxysilane, di-n-propyldi-tert-butoxysilane, di-n- Propyl diphenoxy silane, di-iso-propyl dimethoxy silane, di-iso-propyl diethoxy silane, di-iso-propyl di-n-propoxy silane, di-iso-propyl di-iso-propoxy silane, di-iso-propyl di- n-butoxysilane, di-iso-propyldi-sec-butoxysilane, di-iso-propyldi-tert-butoxysilane, di-iso-propyldiphenoxysilane, di-n-butyldimethoxysilane, di-n-butyldi Ethoxysilane, di-n-butyldi-n-propoxy Silane, di-n-butyldi-iso-propoxysilane, di-n-butyldi-n-butoxysilane, di-n-butyldi-sec-butoxysilane, di-n-butyldi-tert-butoxysilane, di-n- Butyldiphenoxysilane, di-sec-butyldimethoxysilane, di-sec-butyldiethoxysilane, di-sec-butyldi-n-propoxysilane, di-sec-butyldi-iso-propoxysilane, di-sec-butyldi- n-butoxysilane, di-sec-butyldi-sec-butoxysilane, di-sec-butyldi-tert-butoxysilane, di-sec-butyldiphenoxysilane, di-tert-butyldimethoxysilane, di-tert-butyldi Ethoxysilane, di-tert-butyldi-n-propoxysila Di-tert-butyldi-iso-propoxysilane, di-tert-butyldi-n-butoxysilane, di-tert-butyldi-sec-butoxysilane, di-tert-butyldi-tert-butoxysilane, di-tert- Butyldiphenoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenyldi-n-propoxysilane, diphenyldi-iso-propoxysilane, diphenyldi-n-butoxysilane, diphenyldi-sec-butoxysilane, diphenyldi-tert -Butoxysilane, diphenyldiphenoxysilane, bis (3,3,3-trifluoropropyl) dimethoxysilane, methyl (3,3,3-trifluoropropyl) dimethoxysilane and the like.

In the general formula (1), in the compound R ¹ is an organic group having 1 to 20 carbon atoms, and compounds other than the above, for example, bis (trimethoxysilyl) methane, bis (triethoxysilyl) methane Bis (tri-n-propoxysilyl) methane, bis (tri-iso-propoxysilyl) methane, bis (trimethoxysilyl) ethane, bis (triethoxysilyl) ethane, bis (tri-n-propoxysilyl) ethane, Bis (tri-iso-propoxysilyl) ethane, bis (trimethoxysilyl) propane, bis (triethoxysilyl) propane, bis (tri-n-propoxysilyl) propane, bis (tri-iso-propoxysilyl) propane, bis (Trimethoxysilyl) benzene, bis (triethoxysilyl) benzene, bis (to Examples thereof include bissilylalkanes such as (ri-n-propoxysilyl) benzene and bis (tri-iso-propoxysilyl) benzene, and bissilylbenzene.

In the general formula (1), examples of the compound in which R ¹ is a group containing a Si atom include hexamethoxydisilane, hexaethoxydisilane, hexa-n-propoxydisilane, and hexa-iso-propoxydisilane. Examples thereof include dialkyltetraalkoxydisilanes such as alkoxydisilanes, 1,2-dimethyltetramethoxydisilane, 1,2-dimethyltetraethoxydisilane, and 1,2-dimethyltetrapropoxydisilane.

The solvent used in the sol-gel method needs to be able to dissolve the silicon alkoxide component used in the sol-gel method, and a mixed solution of water and an organic solvent is used.
Examples of the organic solvent that can dissolve the silicon alkoxide component used in the sol-gel method include aprotic solvents (2,5-dimethylformamide (DMF), tetrahydrofuran (THF), chloroform, toluene, etc.), protic solvents (methanol and methanol). Alcohols such as ethanol) and the like. These may be used alone or in combination of two or more.

Examples of the aprotic solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-iso-propyl ketone, methyl-n-butyl ketone, methyl-iso-butyl ketone, methyl-n-pentyl ketone, methyl-n- Hexyl ketone, diethyl ketone, dipropyl ketone, di-iso-butyl ketone, trimethylnonanone, cyclohexanone, cyclopentanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, γ-butyrolactone, γ-valerolactone, etc. Ketone solvents;
Diethyl ether, methyl ethyl ether, methyl-n-di-n-propyl ether, di-iso-propyl ether, tetrahydrofuran, methyltetrahydrofuran, dioxane, dimethyl dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol di-n- Propyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl mono-n-propyl ether, diethylene glycol methyl mono-n-butyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di-n- Butyl ether, diethylene glycol Methyl methyl mono-n-hexyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol methyl ethyl ether, triethylene glycol methyl mono-n-butyl ether, triethylene glycol di-n-butyl ether, triethylene glycol methyl mono- n-hexyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetradiethylene glycol methyl ethyl ether, tetraethylene glycol methyl mono-n-butyl ether, diethylene glycol di-n-butyl ether, tetraethylene glycol methyl mono-n-hexyl ether, Tetraethylene glycol di-n-butyl ether, propylene Glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol di-n-propyl ether, propylene glycol dibutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol methyl ethyl ether, dipropylene glycol methyl mono-n-butyl ether, Dipropylene glycol di-n-propyl ether, dipropylene glycol di-n-butyl ether, dipropylene glycol methyl mono-n-hexyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether, tripropylene glycol methyl ethyl ether, tripropylene Glycol methyl mono-n-butyl ether, Ripropylene glycol di-n-butyl ether, tripropylene glycol methyl mono-n-hexyl ether, tetrapropylene glycol dimethyl ether, tetrapropylene glycol diethyl ether, tetradipropylene glycol methyl ethyl ether, tetrapropylene glycol methyl mono-n-butyl ether, di Ether solvents such as propylene glycol di-n-butyl ether, tetrapropylene glycol methyl mono-n-hexyl ether, tetrapropylene glycol di-n-butyl ether;
Methyl acetate, ethyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methyl pentyl acetate 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, nonyl acetate, methyl acetoacetate, ethyl acetoacetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether , Dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, glycol diacetate, methoxytriglycol acetate, ethyl propionate, n-butyrate propionate , Propionic acid i- amyl, diethyl oxalate, ester solvents such as oxalic di -n- butyl;
Ethylene glycol methyl ether propionate, ethylene glycol ethyl ether propionate, ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, diethylene glycol methyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol-n-butyl ether acetate, propylene glycol methyl ether acetate Ether acetate solvents such as propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, dipropylene glycol methyl ether acetate, dipropylene glycol ethyl ether acetate;
Acetonitrile, N-methylpyrrolidinone, N-ethylpyrrolidinone, N-propylpyrrolidinone, N-butylpyrrolidinone, N-hexylpyrrolidinone, N-cyclohexylpyrrolidinone, N, N-dimethylformamide, N, N-dimethylacetamide, N, N- Dimethyl sulfoxide etc. are mentioned, These are used individually by 1 type or in combination of 2 or more types.

Examples of protic solvents include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, sec-butanol, t-butanol, n-pentanol, i-pentanol, and 2-methylbutanol. , Sec-pentanol, t-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, n-octanol, 2-ethylhexanol, sec- Octanol, n-nonyl alcohol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, phenol, cyclohexanol, methylcyclohexano Le, benzyl alcohol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, alcohol solvents such as tripropylene glycol;
Ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-n-hexyl ether, ethoxytriglycol, tetraethylene glycol mono-n -Ether solvents such as butyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether;
Examples include ester solvents such as methyl lactate, ethyl lactate, n-butyl lactate, and n-amyl lactate, and alcohol solvents are preferred from the viewpoint of storage stability. Among these, ethanol, isopropyl alcohol, propylene glycol propyl ether and the like are preferable from the viewpoint of suppressing coating unevenness and repellency. These are used singly or in combination of two or more.

  In the sol-gel reaction, a catalyst is appropriately used. Among these, an onium salt is preferable and a quaternary ammonium salt is more preferable from the viewpoint that the mechanical strength of the coating layer made of the obtained silica-based material can be improved and the stability of the composition can be increased. .

  As one of the onium salt compounds, for example, a salt formed from a nitrogen-containing compound and at least one selected from an anionic group-containing compound and a halogen atom can be given. The atom bonded to nitrogen of the nitrogen-containing compound is at least selected from the group consisting of H atom, F atom, B atom, N atom, Al atom, P atom, Si atom, Ge atom, Ti atom, and C atom. One type is preferable. Examples of the anionic group include a hydroxyl group, a nitrate group, a sulfate group, a carbonyl group, a carboxyl group, a carbonate group, and a phenoxy group.

  Examples of these onium salt compounds include ammonium hydroxide, ammonium fluoride, ammonium chloride, ammonium bromide, ammonium iodide, ammonium phosphate, ammonium nitrate, ammonium borate, ammonium sulfate, ammonium formate, and ammonium maleate. , Ammonium fumarate, ammonium phthalate, ammonium malonate, ammonium succinate, ammonium tartrate, ammonium malate, ammonium lactate, ammonium citrate, ammonium acetate, ammonium propionate, butanoic acid Ammonium salt, ammonium pentanoate, ammonium hexanoate, ammonium heptanoate, ammonium octanoate, ammonium nonanoate Nium salt, ammonium decanoate, ammonium oxalate, ammonium adipate, ammonium sebacate, ammonium butyrate, ammonium oleate, ammonium stearate, ammonium linoleate, ammonium linolenate, ammonium salicylate Benzenesulfonic acid ammonium salt, benzoic acid ammonium salt, p-aminobenzoic acid ammonium salt, p-toluenesulfonic acid ammonium salt, methanesulfonic acid ammonium salt, trifluoromethanesulfonic acid ammonium salt, trifluoroethanesulfonic acid ammonium salt, etc. An ammonium salt compound is mentioned.

  Further, the ammonium moiety of the ammonium salt compound is methylammonium, dimethylammonium, trimethylammonium, tetramethylammonium, ethylammonium, triethylammonium, tetraethylammonium, propylammonium, dipropylammonium, tripropylammonium, tetrapropylammonium, Examples also include ammonium salt compounds substituted with butylammonium, dibutylammonium, tributylammonium, tetrabutylammonium, ethanolammonium, diethanolammonium, triethanolammonium, and the like.

  In these onium salt compounds, tetramethylammonium nitrate, tetramethylammonium acetate, tetramethylammonium propionate, tetramethylammonium maleate, tetramethylammonium sulfate from the viewpoint of accelerating the curing of the coating layer made of a silica-based material. Ammonium salts such as salts are preferred. These are used singly or in combination of two or more.

In addition, as a fluorescent substance particle, a europium complex is preferable. Specifically, in addition to the central element europium (Eu), a molecule to be a ligand is required. However, in the present invention, the ligand is not limited and any molecule that forms a complex with europium. Anything
As an example of a fluorescent substance particle composed of such a europium complex, N.I. Kamata, D.H. Terunuma, R.A. Ishii, H.M. Satoh, S .; Aihara, Y. et al. Yaoita, S .; Tonsyo, J .; Organometallic Chem. , 685, 235, 2003. Eu (TTA) ₃ phen etc. mentioned in the above can be used. A method for producing Eu (TTA) ₃ Phen is described, for example, in Masa Mitsui, Shinji Kikuchi, Tokuji Miyashita, Yutaka Amano, J. et al. Mater. Chem. Reference may be made to the method disclosed in 2003, 13, 285-2879.
In this invention, although a ligand is not limited, As a neutral ligand, a nitrogen-containing aromatic heterocyclic compound and (beta) -diketone are preferable.

  By using a europium complex for the fluorescent substance particles, a solar cell module having high power generation efficiency can be realized. The europium complex converts light in the ultraviolet region into light in the red wavelength region with high wavelength conversion efficiency, and the converted light contributes to power generation in the solar battery cell.

  In addition, the confirmation that the coating layer is formed around the fluorescent substance particles is indirect, but, for example, the high temperature and high humidity resistance is measured under the conditions of 85 ° C. and 85% RH, and the fluorescent substance particles before the coating layer is formed. Judged by the presence or absence of improvement in high temperature and high humidity resistance.

  The coated phosphor material in the present invention can be controlled to have a desired shape such as solid particles, liquid, film, etc., depending on the components of silicon alkoxide and the adjustment method.

The method for measuring the primary particle diameter of the coated fluorescent substance particles can be performed using, for example, an electron microscope.
In order to set the primary particle diameter of the coated fluorescent substance particles obtained by the sol-gel method to 100 nm, the reaction time, temperature, blending ratio, type of solvent, catalyst, etc. in the sol-gel method may be appropriately adjusted.

  Silica-based materials usually have a refractive index of 1.4 to 1.5. For this reason, as a transparent sealing resin (used as a dispersion medium resin) used therefor, since the scattering does not occur if the refractive index is comparable, such a refractive index is desired.

The transparent encapsulating resin of the wavelength conversion type solar cell encapsulant is required to have at least the same degree or higher refraction than the incident side layer.
Specifically, when the plurality of light transmissive layers are layer 1, layer 2,..., Layer m from the light incident side, and their refractive indices are n1, n2,. It is preferable that n1 ≦ n2 ≦.

  In this invention, a solar cell module is comprised from required members, such as an anti-reflective film, protective glass, a wavelength conversion type solar cell sealing material, a photovoltaic cell, a back film, a cell electrode, a tab wire. Among these members, the light-transmitting layer having light transmittance includes an antireflection film, a protective glass, the wavelength conversion type solar cell sealing material of the present invention, a SiNx: H layer and a Si layer of the solar cell, and the like. Can be mentioned.

  In the present invention, the order of lamination of the light-transmitting layers mentioned above is usually an antireflection film, protective glass, and the wavelength conversion type solar cell sealing of the present invention, which are formed in order from the light receiving surface of the solar cell module. The material is a SiNx: H layer or Si layer of the solar battery cell.

  That is, in the wavelength conversion type solar cell encapsulant of the present invention, the external light entering from any angle has little reflection loss, and the refractive index of the wavelength conversion type solar cell encapsulant is efficiently introduced into the solar cell. The light-transmitting layer disposed on the light incident side from the wavelength conversion type solar cell encapsulant, that is, higher than the refractive index of the antireflection film, protective glass, etc., and the reflection of the wavelength conversion type solar cell encapsulant The refractive index of the light transmissive layer disposed on the incident side, that is, the SiNx: H layer (also referred to as “cell antireflection film”) and the Si layer of the solar battery cell is preferably lower.

  Specifically, the light transmitting layer disposed on the light incident side from the wavelength conversion type solar cell encapsulant, that is, the refractive index of the antireflection film is 1.25 to 1.45, and the refractive index of the protective glass is Usually, about 1.45 to 1.55 is used. The refractive index of the light transmissive layer disposed on the light incident side of the wavelength conversion type solar cell encapsulant, that is, the SiNx: H layer (cell antireflection film) of the solar cell is usually 1.9 to 2. The refractive index of about 1 and the Si layer or the like is usually about 3.3 to 3.4. From the above, the refractive index of the wavelength conversion type solar cell encapsulant of the present invention is set to 1.5 to 2.1, preferably 1.5 to 1.9.

In addition, the preferable refractive index of the other layer of a light transmissive layer is as showing below. For example, when the three layers from the light incident side of the light transmissive layer are a layer, b layer, and c layer, the refractive indexes na, nb, and nc of the respective layers satisfy or approximate the following formula: Is preferred.
nb = √na · nc

  It is preferable that the wavelength conversion type solar cell sealing material of this invention is arrange | positioned on the light-receiving surface of a photovoltaic cell. By doing so, it is possible to follow the uneven structure including the texture structure of the solar cell light receiving surface, the cell electrode, the tab line and the like without a gap.

  In any case, for the wavelength conversion, the transparent encapsulating resin composition contains the above-described coated phosphor material, preferably a coated phosphor material coated with europium complex particles.

  A preferable blending amount of the coated fluorescent substance in the resin composition for wavelength conversion type solar cell encapsulating material of the present invention is preferably 0.1 to 10% by mass in terms of mass concentration of the europium complex with respect to the total nonvolatile content. If it is 0.1% by mass or less, the light emission efficiency tends to be low, and if it is 10% by mass or more, the light emission efficiency tends to decrease due to concentration quenching, or the power generation effect tends to be adversely affected by scattering of incident light.

As described above, a photocurable resin, a thermosetting resin, a thermoplastic resin, or the like is preferably used as the transparent sealing resin of the resin composition.
Conventionally, as a resin used as a transparent sealing material for a solar cell, an ethylene-vinyl acetate copolymer imparted with thermosetting property is widely used as described in Patent Documents 19 to 26 described above. However, the present invention is not limited to a sealing resin that also serves as a dispersion medium, and any of a thermoplastic resin, a thermosetting resin, and a photocurable resin can be used.

  As described above, when a photocurable resin is used for the dispersion medium resin (transparent sealing resin) of the resin composition for wavelength conversion type solar cell encapsulant, the resin configuration and photocuring method of the photocurable resin are particularly limited. There is no. For example, in the photocuring method using a photoradical initiator, the wavelength-converting solar cell encapsulant resin composition includes (A) a photocurable resin, (B) a crosslinkable monomer, and ( C) A dispersion medium resin such as a photoinitiator that generates free radicals by light or heat.

  Here, as the photocurable resin (A), a copolymer obtained by copolymerizing acrylic acid or methacrylic acid and alkyl esters thereof and other vinyl monomers copolymerizable therewith as a constituent monomer is used. These copolymers can be used alone or in combination of two or more. Examples of the alkyl acrylate ester or alkyl methacrylate ester include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, and the like. Acrylic acid unsubstituted alkyl ester or methacrylic acid unsubstituted alkyl ester, acrylic acid substituted alkyl ester or methacrylic acid substituted alkyl ester in which a hydroxyl group, an epoxy group, a halogen group or the like is substituted on these alkyl groups.

  Examples of other vinyl monomers that can be copolymerized with acrylic acid, methacrylic acid, alkyl acrylate ester, or alkyl methacrylate ester include acrylamide, acrylonitrile, diacetone acrylamide, styrene, vinyl toluene, and the like. These vinyl monomers can be used alone or in combination of two or more. Moreover, it is preferable that the weight average molecular weight of the dispersion medium resin of (A) component is 10,000-300,000 from the point of coating-film property and coating-film intensity | strength.

  (B) As a crosslinkable monomer, for example, dicyclopentenyl (meth) acrylate; tetrahydrofurfuryl (meth) acrylate; benzyl (meth) acrylate; obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid. Compounds such as polyethylene glycol di (meth) acrylate (having 2 to 14 ethylene groups), trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethoxytri (meta ) Acrylate, trimethylolpropane propoxy tri (meth) acrylate, tetramethylol methane tri (meth) acrylate, tetramethylol methane tetra (meth) acrylate, polypropylene glycol di (meth) acrylate (propylene) Dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, bisphenol A polyoxyethylene di (meth) acrylate, bisphenol A dioxyethylene di (meth) Acrylate, bisphenol A trioxyethylene di (meth) acrylate, bisphenol A decaoxyethylene di (meth) acrylate, etc.); compounds obtained by adding an α, β-unsaturated carboxylic acid to a glycidyl group-containing compound (for example, tri Methylolpropane triglycidyl ether triacrylate, bisphenol A diglycidyl ether diacrylate, etc.); a substance having a polyvalent carboxylic acid (for example, phthalic anhydride) and a hydroxyl group and an ethylenically unsaturated group (for example, β-hydroxy ester) (Meth) acrylate); alkyl esters of acrylic acid or methacrylic acid (for example, (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid butyl ester, (meth) acrylic Acid 2-ethylhexyl ester); urethane (meth) acrylate (for example, reaction product of tolylene diisocyanate and 2-hydroxyethyl (meth) acrylic acid ester, trimethylhexamethylene diisocyanate, cyclohexanedimethanol and 2-hydroxyethyl (meth)) A reaction product with an acrylic ester, etc.);

  Particularly preferred (B) crosslinkable monomers are trimethylolpropane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate in the sense that the crosslink density and reactivity can be easily controlled. Bisphenol A polyoxyethylene dimethacrylate. In addition, the said compound is used individually or in combination of 2 or more types.

  In particular, when the refractive index of the wavelength conversion type solar cell encapsulant or its lower layer (anti-light-receiving surface side) is increased, bromine, sulfur, (A) a photocurable resin and / or (B) a crosslinkable monomer are used. It is advantageous to include atoms. Examples of the bromine-containing monomer include New Frontier BR-31, New Frontier BR-30, and New Frontier BR-42M manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Examples of the sulfur-containing monomer composition include IU-L2000, IU-L3000, and IU-MS1010 manufactured by Mitsubishi Gas Chemical Company. However, the bromine and sulfur atom-containing monomers (polymers containing them) used in the present invention are not limited to those listed here.

  (C) The photoinitiator is preferably a photoinitiator that generates free radicals by ultraviolet light or visible light. For example, benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isobutyl ether, and benzoin phenyl ether Benzophenones such as benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), N, N′-tetraethyl-4,4′-diaminobenzophenone, benzyldimethyl ketal (Ciba Specialty) Chemicals, IRGACURE (Irgacure) 651), benzyl ketals such as benzyl diethyl ketal, 2,2-dimethoxy-2-phenylacetophenone, p-tert-butyldichloroacetate Enone, acetophenones such as p-dimethylaminoacetophenone, xanthones such as 2,4-dimethylthioxanthone and 2,4-diisopropylthioxanthone, or hydroxycyclohexyl phenyl ketone (manufactured by Ciba Specialty Chemicals, IRGACURE (Irgacure) 184) 1- (4-isopropylphenyl) -2-vitoxy-2-methylpropan-1-one (Merck, Darocur 1116), 2-hydroxy-2-methyl-1-phenylpropan-1-one (Merck) Manufactured, Darocur 1173) and the like, and these may be used alone or in combination of two or more.

  Examples of (C) photoinitiators that can be used as photoinitiators include 2,4,5-triallylimidazole dimer, 2-mercaptobenzoxazole, leucocrystal violet, and tris (4-diethylamino-2). Combinations with -methylphenyl) methane and the like are also mentioned. In addition, although there is no photoinitiation by itself, an additive that can be used as a sensitizer system with a better photoinitiation performance as a whole when used in combination with the above substances, such as triethanolamine for benzophenone, etc. Secondary amines can be used.

Moreover, what is necessary is just to change the said (C) photoinitiator into a thermal initiator in order to make it thermosetting.
(C) The thermal initiator is preferably an organic peroxide that generates free radicals by heat. For example, isobutyl peroxide, α, α′bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodecano , Di-n-propyl peroxydicarbonate, di-s-butyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl neodecanoate, bis (4-t-butylcyclohexyl) peroxydi Carbonate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, di-2-ethoxyethylperoxydicarbonate, di (ethylhexylperoxy) dicarbonate, t-hexylneodecanoate, dimethoxybutylperoxydi Carbonate, di (3-methyl-3-methoxy) Tilperoxy) dicarbonate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, 1, 1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, succinic peroxide, 2,5-dimethyl-2,5-di (2-ethylhexanoyl) hexane, 1-cyclohexyl-1- Methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, 4-methylbenzoyl peroxide, t-butylperoxy-2-ethylhexanoate, m-toluonoylbenzoyl Peroxide, benzoyl peroxy Side, t-butylperoxyisobutyrate, 1,1-bis (t-butylperoxy) 2-methylcyclohexane, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexanone, 2,2-bis (4,4-dibutylperoxycyclohexyl) propane, 1,1-bis (t-butylperoxy) cyclododecane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t -Butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2, -Dimethyl-2,5-di (m-toluoylperoxy) hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, t-hexylperoxybenzoate, 2,5- Dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxyacetate, 2,2-bis (t-butylperoxy) butane, t-butylperoxybenzoate, n-butyl-4,4- Bis (t-butylperoxy) valerate, di-t-butylperoxyisophthalate, α, α′bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5- Di (t-butylperoxy) hexane, t-butylcumyl peroxide, di-t-butyl Peroxy, p-menthane hydroperoxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne, diisopropylbenzene hydroperoxide, t-butyltrimethylsilyl peroxide, 1,1,3,3- Tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-hexyl hydroperoxide, t-butyl hydroperoxide, 2,3-dimethyl-2,3-diphenylbutane, and the like can be used.

  The above is an example of the acrylic photocurable resin and the thermosetting resin, but the epoxy photocurable resin and the thermosetting resin that are usually used are also included in the wavelength conversion type solar cell encapsulant of the present invention. It can be used as a dispersion medium resin. However, since the curing of the epoxy is ionic, the coated fluorescent substance or the rare earth metal complex that is a fluorescent substance is easily affected and may cause deterioration or the like, and therefore acrylic is more preferable.

  When a thermoplastic resin that flows by heating or pressurization is used for the dispersion medium resin of the wavelength conversion type solar cell encapsulant resin composition, for example, natural rubber, polyethylene, polypropylene, polyvinyl acetate, polyisoprene, poly- (Di) enes such as 1,2-butadiene, polyisobutene, polybutene, poly-2-heptyl-1,3-butadiene, poly-2-t-butyl-1,3-butadiene, poly-1,3-butadiene , Polyethers such as polyoxyethylene, polyoxypropylene, polyvinyl ethyl ether, polyvinyl hexyl ether, and polyvinyl butyl ether, polyesters such as polyvinyl acetate and polyvinyl propionate, polyurethane, ethyl cellulose, polyvinyl chloride, polyacrylonitrile, polymethacrylate Ronitrile, poly Lufone, phenoxy resin, polyethyl acrylate, polybutyl acrylate, poly-2-ethylhexyl acrylate, poly-t-butyl acrylate, poly-3-ethoxypropyl acrylate, polyoxycarbonyl tetramethacrylate, polymethyl acrylate, polyisopropyl methacrylate, poly Dodecyl methacrylate, polytetradecyl methacrylate, poly-n-propyl methacrylate, poly-3,3,5-trimethylcyclohexyl methacrylate, polyethyl methacrylate, poly-2-nitro-2-methylpropyl methacrylate, poly-1,1-diethyl Poly (meth) acrylic acid esters such as propyl methacrylate and polymethyl methacrylate can be used as the dispersion medium resin.

  Two or more kinds of these thermoplastic resins may be copolymerized as required, or two or more kinds may be blended and used.

  Furthermore, epoxy acrylate, urethane acrylate, polyether acrylate, polyester acrylate, or the like can be used as a copolymer resin with the above resin. In particular, urethane acrylate, epoxy acrylate, and polyether acrylate are excellent from the viewpoint of adhesiveness.

  As epoxy acrylate, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, allyl alcohol diglycidyl ether, resorcinol diglycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, polyethylene glycol diglycidyl ether And (meth) acrylic acid adducts such as trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, pentaerythritol tetraglycidyl ether, and sorbitol tetraglycidyl ether.

  A polymer having a hydroxyl group in the molecule, such as epoxy acrylate, is effective in improving adhesion. These copolymer resins can be used in combination of two or more as required. The softening temperature of these resins is preferably 200 ° C. or less, and more preferably 150 ° C. or less from the viewpoint of handleability. Considering that the use environment temperature of the solar cell unit is usually 80 ° C. or lower and workability, the softening temperature of the resin is particularly preferably 80 to 120 ° C.

The composition of the other resin composition when a thermoplastic resin is used as the dispersion medium resin is not particularly limited as long as the above-described coated fluorescent substance is contained, but usually used components such as a plasticizer and a flame retardant , Stabilizers and the like can be contained.
As the dispersion medium resin of the wavelength conversion type solar cell encapsulant of the present invention, as described above, photocurability, thermosetting, thermoplasticity, and the resin is not particularly limited, but as a particularly preferable resin, The composition which mix | blended the thermal radical initiator with the ethylene-vinyl acetate copolymer widely utilized as the sealing material for conventional solar cells is mentioned.

The wavelength conversion type solar cell encapsulant of the present invention is (1) a phosphor particle coating step in which phosphor particles are coated with silica glass by a sol-gel reaction using silicon alkoxide to obtain a coated phosphor material body having a coating layer. When,
(2) A resin composition is prepared by mixing or dispersing the coated fluorescent substance body in a dispersion medium resin (transparent sealing resin), and using the resin composition, a wavelength conversion type solar cell sealing material is formed into a sheet shape. It can manufacture by the process including the sheet | seat formation process to form.

  The wavelength conversion type solar cell encapsulant of the present invention is preferably formed in a sheet shape from the viewpoint of ease of use.

<Solar cell module and manufacturing method thereof>
The present invention also covers a solar module using the wavelength conversion type solar cell encapsulant.
The wavelength conversion type solar cell encapsulant of the present invention is used as one of the light transmissive layers of a solar cell module having a plurality of light transmissive layers and solar cells.

  By using a europium complex as the fluorescent material used for the wavelength conversion type solar cell sealing material of the present invention, a solar cell module having high power generation efficiency can be realized. The europium complex converts light in the ultraviolet region into light in the red wavelength region with high wavelength conversion efficiency, and the converted light contributes to power generation in the solar battery cell.

Using the sheet-shaped resin composition layer, which is the wavelength conversion type solar cell encapsulant of the present invention, a wavelength conversion type solar cell encapsulant is formed on the solar cell to produce a solar cell module.
Specifically, the wavelength-converting solar cell encapsulant of the present invention (particularly preferably in the form of a sheet) is used in place of the normal encapsulant sheet, without any difference from the silicon crystal solar cell module manufacturing method. Only the difference. Generally, a silicon crystal solar cell module is first made into a sheet-like sealing material (mostly an ethylene-vinyl acetate copolymer with a thermal radical initiator on a cover glass which is a light receiving surface, and a thermosetting type. ). In this invention, the wavelength conversion type solar cell sealing material of this invention is used for the sealing material used here. Next, the cells connected by tab wires are placed, and a sheet-shaped sealing material (in the present invention, a wavelength conversion type solar cell sealing material may be used only on the light receiving surface side. And a back sheet, and a module using a vacuum press laminator dedicated to the solar cell module.

  At this time, the hot plate temperature of the laminator is a temperature necessary for the sealing material to soften and melt, wrap the cell, and further harden, and is usually 120 to 180 ° C., most of which is 140 to 160 ° C. Designed to cause these physical and chemical changes.

The wavelength conversion type solar cell encapsulant of the present invention is in a state before being made into a solar module, specifically, in a semi-cured state when a curable resin is used. In addition, the refractive index of the wavelength conversion type solar cell sealing material in a semi-cured state and the wavelength conversion type solar cell sealing material after being cured (after being formed into a solar module) is not greatly changed.
Although there is no restriction | limiting in particular in the form of the wavelength conversion type solar cell sealing material of this invention, It is preferable that it is a sheet form from the ease of manufacture of a solar module.

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

Example 1
<Synthesis of phosphor particles>
First, phosphor particles are synthesized. 200 mg of 4,4,4-trifluoro-1- (thienyl) -1,3-butanedione (TTA) was dissolved in 7 ml of ethanol, and 1.1 ml of 1M sodium hydroxide was added thereto and mixed. 6.2 mg of 1,10-phenanthroline dissolved in 7 ml of ethanol is added to the above mixed solution and stirred for 1 hour, and then a solution of 103 ml of EuCl ₃ · 6H ₂ O in 3.5 ml is added to obtain a precipitate. This was filtered off, washed with ethanol, and dried to obtain fluorescent substance particles Eu (TTA) ₃ Phen.

<Preparation of coated phosphor material>
Using the Eu (TTA) ₃ Phen obtained as described above, a sol-gel solution was prepared in the amounts shown in Table 1 using the materials shown in Table 1.

  In the molar ratio shown in Table 1, the materials (a) to (d) in the table are mixed, and the other materials (e) to (f) are mixed. After thoroughly mixing and stirring, both were mixed and stirred for 2 hours to obtain a coated phosphor material solution. This solution was put into a Teflon (registered trademark) vat, and volatile components were removed in an oven at 120 ° C. for 5 hours.

<Adjustment of resin composition for wavelength conversion type solar cell encapsulant>
As a transparent sealing resin (dispersion medium resin), 100 g of ethylene-vinyl acetate resin manufactured by Tosoh Corporation, Ultrasen 634, and a peroxide thermal radical initiator manufactured by Arkema Yoshitomi Co., Ltd. are used. 5 g, a silane coupling agent manufactured by Toray Dow Corning Co., Ltd., 0.5 g of SZ6030, and 2 g of the coated phosphor material, kneaded at 100 ° C., put on a release sheet, and cooled to room temperature. A resin composition for wavelength conversion type solar cell encapsulant was obtained.

<Preparation of wavelength conversion type solar cell encapsulant sheet>
About 30 g of the resin composition for wavelength conversion type solar cell encapsulant obtained above is sandwiched between release sheets, a 0.6 mm thick stainless steel spacer is used, and a hot plate is adjusted to 80 ° C. I made it.

<Preparation of solar cell encapsulant sheet for back surface>
The composition of the above-mentioned wavelength conversion type solar cell encapsulant sheet, which did not contain the coated phosphor material, was produced by the same method.

<Production of wavelength conversion type solar cell module>
On the tempered glass (manufactured by Asahi Glass Co., Ltd.) as a protective glass, the wavelength conversion type solar cell sealing material sheet is placed, and the photovoltaic cell is placed on the photovoltaic cell so that the electromotive force can be taken out to the outside. Furthermore, a PET film (manufactured by Toyobo Co., Ltd., trade name: A-4300) was placed as a back surface solar cell encapsulant sheet and a back film, and laminated using a vacuum laminator.

<Evaluation of solar cell characteristics>
As a simulated solar ray, using a solar simulator (Wacom Denso Co., Ltd., WXS-155S-10, AM1.5G), current voltage characteristics using an IV curve tracer (Eihiro Seiki Co., Ltd., MP-160), The cell state before module sealing and after module sealing were measured, and the difference between them was evaluated. The measurement results are shown in Table 2 together with the comparative example.

(Comparative Example 1)
<Production of solar cell module>
Tempered glass (manufactured by Asahi Glass Co., Ltd.) as protective glass, EVA resin (manufactured by Mitsui Fabro Co., Ltd., trade name: Soraeva) as a sealing material, solar cell (light-receiving surface facing down), EVA resin Then, a polyethylene terephthalate (PET) film (A-4300, manufactured by Toyobo Co., Ltd.) was stacked as a back film and laminated using a vacuum laminator.
Using the obtained solar cell module, solar cell characteristics were evaluated in the same manner as in Example 1. The measurement results are shown in Table 2.

  As seen in Table 2, the conversion efficiency was η (%), and the comparative example was −0.03%, but in the example, it was + 0.56%.

  The wavelength conversion type solar cell encapsulant of the present invention can reduce sunlight loss due to spectrum mismatch and have a higher visible light transmittance, thereby improving light utilization efficiency and improving power generation efficiency. it can.

Claims (9)

In a wavelength conversion type solar cell sealing material containing a fluorescent material, used as one of the light transmissive layers of a solar cell module having a plurality of light transmissive layers and solar cells,
The fluorescent material is a coated fluorescent material body having fluorescent material particles and a coating layer covering the periphery of the fluorescent material particles with a material having a lower refractive index than the fluorescent material particles,
A wavelength conversion type solar cell encapsulant in which the coated phosphor material is dispersed in a transparent encapsulating resin.   The wavelength-converting solar cell encapsulant according to claim 1, wherein the coated fluorescent substance body is dispersed or mixed in the transparent encapsulating resin at 0.1 to 10 mass percent.   The wavelength conversion type solar cell sealing material according to claim 1 or 2, wherein the substance having a refractive index lower than that of the fluorescent substance is a silica-based material formed by a sol-gel method.   4. The wavelength conversion type according to claim 1, wherein the wavelength conversion type solar cell encapsulant has a multilayer structure, and at least one of the layers has a wavelength conversion function. 5. Solar cell encapsulant.   The wavelength conversion type solar cell encapsulant is disposed on the light receiving surface of the solar cell, and the plurality of light transmissive layers are defined as layer 1, layer 2,..., Layer m from the light incident side. In addition, when these refractive indexes are n1, n2,..., Nm, n1 ≦ n2 ≦. Wavelength conversion type solar cell encapsulant.   The wavelength-converting solar cell sealing material according to any one of claims 1 to 5, wherein the fluorescent material is a europium complex.   The solar cell module which has a wavelength conversion type solar cell sealing material as described in any one of Claims 1-6. A phosphor particle coating step of coating the phosphor particles with a silica-based material by a sol-gel reaction using silicon alkoxide to obtain a coated phosphor body having a coating layer;
The coated phosphor material body is mixed or dispersed in a transparent encapsulating resin to produce a resin composition, and the resin composition is used to form a wavelength conversion type solar cell encapsulant into a sheet form, The manufacturing method of the wavelength conversion type solar cell sealing material as described in any one of Claims 1-6 which has.   In the manufacturing method of the solar cell module which has a some light transmissive layer and a photovoltaic cell, the wavelength conversion type solar cell sealing material as described in any one of Claims 1-6 is laminated | stacked, The said light transmission The manufacturing method of the solar cell module characterized by having the process of comprising one of a property layer.