JP2007012967A - Heat radiation film for solar cell module and solar cell module provided with heat radiation film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the efficiency of heat radiation of a heat radiation film for a solar cell module as well as the solar cell module. <P>SOLUTION: The solar cell module 10 is provided with a translucent surface cover 12, and a cell 14 one side of which is fixed to one side of the surface cover 12. One side of the cell 14 is fixed to the reverse side of the surface cover 12 through an adhesive layer 16. The other side of the cell 14 is provided with the heat radiation film 18. The heat radiation film 18 emits far-infrared radiation when it is heated, and lowers the temperature of the cell 14. The heat radiation film 18 is a one-film radiation coating with heat dissipation characteristics and weather resistance; and is formed of a composition which is composed of a partial hydrolysate of an alkoxy silane compound, alkoxy titanium, and a specific metal compound. Also, a heat radiation film 18 with heat dissipation characteristics which is protected by a weather-resistant film or the like can be formed from a composition which is formed by including a specific metal compound in a fluid material of one of specific alkali metal silicate, a silicone resin emulsion, and a silane compound. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a solar cell module heat dissipation film and a solar cell module, and particularly to a solar cell module heat dissipation that is novel, low-cost, has a radiation cooling function, and can obtain high photoelectric conversion efficiency when applied to a solar cell. Relates to the membrane.

  In recent years, photovoltaic power generation that converts light energy into electrical energy by using a quantum effect peculiar to semiconductors has been attracting attention as a leader of clean energy. As a characteristic of solar power generation, clean energy can be generated quietly because there are no moving parts, it is easy to maintain and easy to automate and unmanned, and it is constant regardless of the size of the power generation equipment. Power generation with efficiency, high modularity due to its modular structure, great scale merit, power generation not only with direct sunlight but also with diffused light, and photovoltaic power generation is the effective use of energy that was originally abandoned There are some.

  However, in order for such solar power generation to be widely spread in general, further cost reduction of solar cell modules and improvement of photoelectric conversion efficiency are required.

  By the way, as a solar cell element that is generally used, a crystalline silicon solar cell element such as a single crystal silicon type solar cell element, a polycrystalline silicon type solar cell element, an amorphous silicon solar cell element comprising a single junction type or a tandem structure type, etc. III-V group compound semiconductor solar cell elements such as gallium arsenide (GaAs) and indium phosphorus (lnP), and II-VI group compound semiconductor solar cell elements such as cadmium telluride (CdTe) and copper indium selenide (CuInSe2). .

  The structure of the solar cell module is broadly classified into (a) a filling type, (b) a super straight type, and (c) a substrate type. This type of solar cell module is usually installed on a roof mounted on a building or a roof of a house with a dedicated stand fixed thereon.

  However, in such installation means, there is a problem that the cost of the dedicated pedestal increases, and therefore, a building material integrated solar cell module having both functions of the solar cell module and the building material has been proposed.

  In the building material integrated solar cell module, the solar cell module is installed directly on the roof surface. However, with such an installation method, since there is no ventilation part for cooling, the solar cell module is operated at the time of photovoltaic power generation (during operation). ) In particular, the temperature rises greatly in summer.

  Such a temperature rise is a main cause of the problem that the photoelectric conversion efficiency is lowered, for example, when the cell is of a crystalline silicon type. In general, it is known that there is a decrease in performance of about 0.4% / ° C. as the temperature rises. For example, when the temperature of the solar cell module is 60 to 70 ° C. or higher (when the weather is clear in summer) There is a problem that only about 80% of the performance of the condition can generate power.

In order to solve the problems associated with such a temperature rise, cells are embedded in a heat dissipation layer (synthetic resin containing a thermally conductive filler) to dissipate the heat generated by the solar cell module during operation, and cell heat dissipation. This is disclosed in Patent Document 1. However, the solving means disclosed in Patent Document 1 has the following technical problems.
JP 2004-172255 A

  That is, in the solar cell module disclosed in Patent Document 1, a synthetic resin in which fillers that enhance thermal conductivity such as carbon, glass fiber, alumina powder, and metal powder are dispersed in the heat dissipation layer, for example, an epoxy resin is used. However, even though the heat dissipation by the filler is mainly improved by the filler, there is a drawback that the cooling effect is not sufficient because it is dispersed in the epoxy resin.

  This invention is made | formed in view of such a conventional problem, The place made into the objective is the solar cell module of the solar cell module by providing the thermal radiation film | membrane for solar cell modules with which sufficient cooling effect is acquired. It is to increase the photoelectric conversion efficiency.

  To achieve the above object, the present invention provides a solar cell module comprising a translucent surface cover and a cell having one surface fixed to the surface cover, provided on the other surface of the cell. The heat dissipation film has a cooling function of emitting far infrared rays and reducing the temperature increase of the cell when the cell receives light and the temperature rises.

  According to the solar cell module configured in this way, the other surface of the cell is provided with a heat radiation film that emits far infrared rays by increasing the temperature and lowers the temperature of the cell. As is apparent, the cell temperature can be sufficiently lowered, and as a result, high photoelectric conversion efficiency can be obtained.

  The heat dissipation film efficiently emits far infrared rays when the temperature of the cell is in the range of 50 ° C to 130 ° C.

  The heat dissipation film can have both predetermined heat dissipation and weather resistance.

  The heat-dissipating film can be provided with a weather-resistant film on the radiation surface that is open to the atmosphere.

  The heat dissipation film may be provided with an overcoat material having weather resistance on a radiation surface that is open to the atmosphere.

  The far-infrared rays emitted by the heat dissipation film have an emissivity of 70% or more in a specific energy peak wavelength region. The specific energy peak wavelength region is 7.2 to 9.0 μm from the “Wien's displacement law” in order for the solar cell to efficiently emit far infrared rays in the range of 50 ° C. to 130 ° C. When the emissivity from the radiation film at this cell temperature of 50 ° C. to 130 ° C. (emissivity for a complete black body) is high, the cooling effect is high and the emissivity is 70% or more. The “Wien's displacement law” means that, in the case of far-infrared rays, the maximum emission wavelength (λm) is inversely proportional to the absolute temperature (T), and can be expressed as λ = 2.897 / T. it can.

  Conventionally, the far-infrared radiation characteristics of substances (eg, zeolite, cordierite, talc, dolomite, etc.) that have a high far-infrared radiation ability are 7.2 to 9 as much as the heat dissipation film. Although it has an emissivity of about 85% to 95% at an energy peak wavelength of 0.0 μm, these substances exist in the form of metal ores, etc., and in general, when trying to process them into a film or plate shape Is solid-sintered through a process such as high-temperature baking at 800 ° C. or higher after being finely divided, but the heat-curing temperature range is practically less than the heat-resistant temperature of the solar battery cell in the process of forming the heat dissipation film Can not be adopted.

  On the other hand, the heat-dissipating film can be sufficiently dried and cured at a low temperature of 300 ° C. or less, and since it has excellent workability, a stable coating film can be easily formed to a thickness of 150 μm after drying. be able to.

  The film transmits about 20% or more of far infrared rays having a wavelength of 4 to 15 μm necessary for heat dissipation.

  The overcoat material can absorb and emit far infrared rays having a specific energy peak wavelength region.

  The heat dissipation film having both predetermined heat dissipation and weather resistance is formed from a composition in which a specific metal oxide is contained in a liquid material composed of a partially hydrolyzed alkoxysilane compound, alkoxytitanium and an organic solvent. can do. A small amount of an organic polymer such as ethyl cellulose may be mixed.

The partial hydrolyzate of the alkoxysilane compound will be described. The partially hydrolyzed product of the alkoxysilane compound is an oligomer obtained by partially hydrolyzing and condensing the alkoxysilane compound represented by the general formula 1. Examples of R 1 in Chemical Formula ¹ include a methyl group, an ethyl group, a propyl group, an isopropyl group, an aminoethyl group, a glycidylpropyl group (see Chemical Formula 2), and the like, and examples of R ² include a methyl group and an ethyl group. be able to. Here, n is an integer of 1 to 3.

  As the alkoxysilane compound, at least one selected from the substances represented by Chemical Formula 1 is appropriately used. Usually, two to three compounds are mixed and used. A partial hydrolyzate can be obtained by reacting these alkoxysilane compounds with an amount of water smaller than the amount of water (calculated value) required to completely hydrolyze the alkoxysilane in the presence of an acid catalyst. . When trialkoxysilane is present, the heat dissipation film obtained by curing the paint has a three-dimensional structure.

  Alkoxytitanium is represented by Formula 3. As R in the formula, a methyl group, an ethyl group, a propyl group, or a butyl group can be preferably used.

  Organic solvents are methyl alcohol, ethyl alcohol, isopropyl alcohol, 1-butanol, 2-butanol, diacetone alcohol, butyl acetate, butyl butyrate, propylene glycol monomethyl ether, butyl carbitol, butyl carbitol acetate, butyl lactate, ethyl Carbitol, ethyl carbitol acetate, isophorone, dipropylene glycol methyl ether, dipropylene glycol n-propyl ether, propylene glycol n-butyl ether, dipropylene glycol dimethyl ether, propylene glycol diacetate, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate , 3-methoxybutanol, 3-methoxybutyl acetate and the like. However, it is not limited to these solvents, and one kind or two or more kinds of solvents can be used in combination.

Specific metal compounds are metal oxides, metal hydroxides, and metal nitrides.
Metal oxides are silicon oxide, potassium titanate, germanium oxide, tin oxide, boron oxide, aluminum oxide, sodium oxide, magnesium oxide, calcium oxide, strontium oxide, barium oxide, titanium oxide, zirconium oxide, manganese oxide, iron oxide, It contains at least one of cobalt oxide, copper oxide, zinc oxide, antimony oxide, bismuth oxide, kaolin, and talc.

  The metal oxide preferably contains one or more of aluminum oxide, silicon oxide, kaolin, potassium titanate, titanium oxide, zirconium oxide and tin oxide, and one kind of aluminum oxide, potassium titanate, silicon oxide and kaolin It is particularly preferable to contain the above. Furthermore, containing potassium titanate fiber helps to prevent cracks during processing of the heat dissipation film and during long-term use.

  The metal hydroxide and metal nitride are the above-mentioned various metal hydroxides and nitrides. It is particularly preferable to contain aluminum hydroxide.

  It was also recognized that these metal oxides, metal hydroxides, and metal nitrides were further improved in properties when treated with a coupling agent. The fumed silica powder subjected to surface hydrophobic treatment is very useful for adjusting the viscosity (viscosity necessary for coating and preparation of a stable heat radiation film) of a liquid agent in which these components are mixed and integrated.

  Ethyl cellulose is particularly effective as the organic polymer to be added in a small amount. By adding this ethyl cellulose, there is an effect in forming a uniform film from the liquid composition when forming the heat dissipation film, and it is also useful for preventing cracks during processing of the heat dissipation film or during long-term use.

  The shape at the time of addition of a specific metal compound is as fine powder or fiber. The particle diameter of the fine powder is preferably in the range of 80 nm to 30 μm and more preferably in the range of 200 nm to 10 μm in terms of the average particle diameter in consideration of the smoothness and heat dissipation of the coating film surface.

  The diameter of the fiber is 1 μm or less, the average length of the fiber is 20 μm or less, and the maximum length is 100 μm or less. If the diameter, average length, and maximum length of the fiber are larger than these values, unevenness will occur when the heat dissipation film is formed by the printing method, and stable printing will not be possible.

  As the ethyl cellulose powder, for example, N-type (having an ethoxyl group substitution degree of 2.41 to 2.51 per one unit of anhydrous glucose) of Hercules USA can be preferably used. Among the N-types, N-50 and N-100 are particularly preferable from the viewpoint of the balance between solubility and the quality of the heat-dissipating film in terms of viscosity. The added ethylcellulose powder may be completely dissolved in the organic solvent or may be partially dissolved.

  When the amount of alkoxy titanium used is 5 to 30 parts by weight with respect to 100 parts by weight of the partially hydrolyzed alkoxysilane compound, good heat dissipation film performance can be obtained.

  If it is less than 5 parts by weight, the pencil hardness of the heat-dissipation film becomes low and cannot be used practically, and if it exceeds 30 parts by weight, for example, the heat-dissipation film easily cracks in the boiling test and cannot be used practically.

  The amount used here is based on a partial hydrolyzate of alkoxysilane compound and alkoxytitanium, which does not contain an organic solvent. The actual amount of alkoxytitanium added depends on the type of alkoxytitanium compound used (for example, whether it is titanium tetrabutoxide or titanium tetrapropoxide), the type of alkoxysilane compound and the proportion of use (especially trialkoxysilane). The amount used).

  Of the alkoxysilane compounds, if the proportion of trialkoxysilane used is large, the amount of alkoxytitanium added may be small. The amount of alkoxytitanium added is preferably in the range of 0.010 to 0.15, expressed as the ratio of titanium element to silicon element.

When the addition amount of titanium is less than 0.010 with respect to silicon element, it becomes difficult to form a cured product having a network structure and a heat dissipation film. On the other hand, when the addition amount of titanium is greater than 0.15 with respect to silicon element, Further, the curing rate of the mixed solution is too high, or the performance of the formed cured product and the heat dissipation film is not sufficient, and for example, cracks are likely to occur during the boiling test.
The upper limit of the addition amount of the specific metal compound may be within a range in which the heat dissipation film choking (the state where the powder is exposed on the surface of the heat dissipation film) does not occur.

  The fumed silica powder subjected to the surface hydrophobization treatment is preferably 19 parts by weight or less based on 100 parts by weight of the partially hydrolyzed alkoxysilane compound. Exceeding this addition amount is not practically preferable because the viscosity increase during storage of the mixed solution is accelerated and small-diameter grains are likely to be generated in the heat dissipation film.

  The ethyl cellulose powder is preferably 13 parts by weight or less based on 100 parts by weight of the partially hydrolyzed alkoxysilane compound. This is because when the amount exceeds this amount, the flame retardancy of the heat dissipation film decreases and the moisture resistance also decreases.

  The proportion of the organic solvent is desirably 30 to 50% with respect to the total amount of the composition in which a specific metal compound is contained in a liquid material composed of a partially hydrolyzed product of an alkoxysilane compound, alkoxytitanium and an organic solvent. Even if the amount of solvent is less than 30% or more than 50%, a heat dissipation film can be formed, but various problems such as difficulty in forming a uniform coating film due to processability when manufacturing the heat dissipation film occur. It is not preferable.

  The thickness of the heat dissipation film is 10 to 100 μm, preferably 20 to 80 μm as a solid. As a method for forming the heat dissipation film, a spraying method such as spraying, a coating method such as roll coating, a printing method such as screen printing, and the like can be used, but the method is not limited to these methods. Absent.

  The liquid composition formed may be dried by heating at room temperature or in a drying furnace, or by hot air such as a dryer. When performing the heat drying treatment, it is necessary to be within the range of the maximum temperature or lower than the heat resistant temperature of the cell, and is performed at 300 ° C. or lower.

  Among the combined heat dissipation and weather resistance of the heat dissipation films obtained from these compositions, heat dissipation is even more than the cooling effect of the heat dissipation layer of solar cell modules currently used industrially. It means a characteristic having an excellent cooling effect, and the cooling effect is obtained by emission (radiation) of far infrared rays. The weather resistance refers to water resistance, moisture resistance, acid resistance due to acid rain, salt water resistance near the coast, polar and tropical regions, and heat and cold repeatability in the day and night. In addition, since the said heat-radiation film | membrane is not directly exposed to sunlight, the weather resistance test by a weatherometer etc. is not essential.

  When a film having a predetermined heat dissipation property and a weather resistance film is provided on the radiation surface and when an overcoat material is provided, the heat dissipation film is any one of an alkali metal silicate, a silicone resin emulsion, and a silane compound. It can form into a film from the composition containing a liquid phase and a specific metal compound. In the case of a silane compound, those to which colloidal silica is added are preferred.

  As specific embodiments of the composition for forming the heat dissipation film, the following three compositions will be described in detail.

  The composition (1) is an aqueous composition containing an alkali metal silicate and water as a liquid phase and a specific metal compound, and silicon oxide is more preferable as the specific metal compound.

  The alkali metal silicate preferably contains at least both sodium silicate and potassium silicate components. Moreover, lithium silicate etc. are mentioned as another alkali metal silicate which can be used together.

  Sodium silicate is a known substance, and for example, a single or mixture of sodium silicates such as sodium disilicate and sodium silicate can be used. As the sodium silicate, commercially available products can be used. Examples of commercially available products include, for example, J sodium silicate No. 1, 58 sodium silicate No. 1, 53 sodium silicate No. 1, 50 sodium silicate No. 1, 47 silicic acid. Soda No. 1, 38 sodium silicate No. 1, 48 sodium silicate No. 2, 45 sodium silicate No. 2, 43 sodium silicate No. 2, J sodium silicate No. 3, sodium silicate No. 4 (above, manufactured by Nippon Chemical Industry Co., Ltd.), etc. Is mentioned. Among these, for example, J sodium silicate No. 1 is a sodium silicate aqueous solution having a sodium silicate concentration of 54.5% by weight.

  Potassium silicate is a known substance, and examples thereof include potassium hydrogen silicate (4-potassium silicate), potassium silicate, and the like. These potassium silicates are used singly or in combination. As the potassium silicate, commercially available products can be used. Examples of commercially available products include 2K potassium silicate, A potassium silicate, B potassium silicate, C potassium silicate, 1K potassium silicate (above, Nippon Chemical Industry ( Etc.). Among these, for example, 2K potassium silicate is an aqueous potassium silicate solution containing 30% by weight of potassium silicate.

  The specific metal compound in the composition (1) is a metal oxide, a metal hydroxide or a metal nitride.

  Metal oxides are silicon oxide, potassium titanate, germanium oxide, tin oxide, boron oxide, aluminum oxide, sodium oxide, magnesium oxide, calcium oxide, strontium oxide, barium oxide, titanium oxide, zirconium oxide, manganese oxide, iron oxide, It contains at least one of cobalt oxide, copper oxide, zinc oxide, antimony oxide, bismuth oxide, kaolin, and talc. The metal oxide preferably contains one or more of aluminum oxide, silicon oxide, kaolin, potassium titanate, titanium oxide, zirconium oxide and tin oxide, and contains aluminum oxide, potassium titanate, silicon oxide and kaolin. It is particularly preferred. Metal hydroxides and metal nitrides are the hydroxides and nitrides of the various metals described above, and specifically include aluminum hydroxide, aluminum nitride, silicon nitride, boron nitride, zirconium nitride, tin nitride, strontium nitride, and nitride. Metal nitrides such as titanium and barium nitride.

  The shape at the time of addition of a specific metal compound is preferably used in the form of a powder, preferably a fine powder. This is because when the fine powder is used, the denseness of the obtained coating film is improved, and the heat resistance, heat dissipation, and mechanical strength of the coating film can be further improved.

  The particle size of the fine powder of the metal compound is preferably in the range of 80 nm to 30 μm and more preferably in the range of 200 nm to 10 μm in terms of average particle size.

  The composition (1) preferably contains 40 to 70% by weight of a liquid phase composed of alkali metal silicate and water, 60 to 30% by weight of a metal compound, 35 to 50% by weight of a liquid phase, and 65 to 65% of a metal compound. More preferably, it contains 50% by weight.

  Moreover, it is preferable that content of sodium silicate of a composition (1) is 3 to 16 weight% in a composition whole quantity, More preferably, it is 3 to 14 weight%.

  The content of potassium silicate is preferably 1.0 to 7.5% by weight, more preferably 1.5 to 7.5% by weight, based on the total amount of the composition. The content ratio of sodium silicate and potassium silicate is preferably 1: 2 to 0.05, more preferably 1: 1.5 to 0.07, by weight.

  The composition (2) is an aqueous composition containing a silicone resin emulsion and a specific metal compound.

  The silicone resin emulsion in the composition (2) is in an emulsion state in which a water-insoluble silicone resin is mainly dispersed in water, and can be obtained, for example, by the method shown below.

  (1) A method in which an alkyl silicate compound or a partially hydrolyzed / condensed product thereof is emulsified with various surfactants to form an aqueous emulsion (Japanese Patent Laid-Open Nos. 58-213046, 62-197369, and Japanese Patent Laid-Open No. 3). -115485, JP-A-3-200793). Further, this emulsion is mixed with an emulsion obtained by emulsion polymerization of a polymerizable vinyl monomer (JP-A-6-344665).

  (2) A method of emulsion polymerization of a vinyl monomer capable of radical polymerization in the presence of a water-soluble polymer obtained by hydrolyzing an alkyl silicate compound in water without using a surfactant (JP-A-8-60098) .

  (3) Hydrolyzing and condensing an alkyl silicate mixture containing vinyl polymerizable alkyl silicate to form an aqueous emulsion containing a solid silicone resin, further adding a radically polymerized vinyl monomer, and emulsion polymerization, A method for obtaining a polymer fine particle (solid) emulsion (JP-A-5-209149, JP-A-7-196750).

  (4) A method in which an alkyl silicate compound is added to an emulsion obtained by emulsion polymerization of radically polymerizable functional groups, hydrolyzed and condensed, and a silicone resin is introduced into the emulsion particles (Japanese Patent Laid-Open Nos. 3-45628 and 8-3409). No.)

  (5) A method of emulsion-polymerizing a vinyl polymerizable functional group-containing alkyl silicate together with a radical polymerizable vinyl monomer to prepare an emulsion (Japanese Patent Laid-Open Nos. 61-9463 and 8-27347).

  Examples of the specific metal compound in the composition (2) include those similar to the specific metal compound used in the composition (1), which are metal oxides, metal hydroxides, and metal nitrides. . The shape of the composition (2) when the metal compound is added is not particularly limited, but it is preferably used in the form of a powder, preferably a fine powder. This is because when the fine powder is used, the denseness of the obtained coating film is improved, and the heat resistance, heat dissipation, and mechanical strength of the coating film can be further improved.

  The particle size of the fine powder of the metal compound is preferably in the range of 80 nm to 30 μm and more preferably in the range of 200 nm to 10 μm in terms of average particle size.

  Among these metal oxides, preferred and particularly preferred are the same as those of the composition (1).

  The surface hardness of the dry coating film formed from the silicone resin emulsion is preferably 5B or more in terms of pencil hardness in consideration of stability during long-term use. The composition (2) preferably contains 30 to 70% by weight of the silicone resin emulsion and 70 to 30% by weight of the metal compound, more preferably 40 to 70% by weight of the silicone resin emulsion and 60 to 30% by weight of the metal compound. Preferably, the silicone resin emulsion is contained in an amount of 45 to 55% by weight and the metal oxide is contained in an amount of 55 to 45% by weight.

The resin concentration of the silicone resin emulsion is preferably 40% or more.
A small amount of latex such as rubber latex can be added to improve the stability of the liquid composition film.

  The composition (3) is a composition containing a silane compound liquid and a specific metal compound. It is preferable to add colloidal silica to these compositions because the silane compound concentration can be increased. The liquid phase is an alkoxysilane solution and / or an aqueous dispersion of colloidal silica, and the specific metal compound is a metal oxide, a metal hydroxide, or a metal nitride.

  Examples of silane compounds such as alkoxysilane in the composition (3) are methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, methyl Tetraalkoxysilanes such as tripropoxysilane, ethyltripropoxysilane, dityldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, etc. Trialkoxysilane (mono-organic group-substituted alkoxysilane); dialkoxysilane (di-organogroup-substituted alkoxysilane), and the like. It can have group, a carboxyl group, a functional group such as a hydroxyl group.

  It is preferable that the alkoxysilane solution, the colloidal silica aqueous dispersion, the silicon oxide powder, the aluminum oxide powder, and the kaolin powder, which are the components of the composition (3), are mixed immediately before use. In particular, the alkoxysilane is preferably stored until it is used in the state of a solution substantially free of water in order to prevent hydrolysis and condensation of the alkoxysilane during storage.

  In order to control the reaction rate of hydrolysis / condensation of alkoxysilane in the composition (3), titanium alkoxide and / or aluminum alkoxide can be added to alkoxysilane.

  Examples of the titanium alkoxide in the composition (3) include tetramethoxy titanium, tetraethoxy titanium, tetrapropoxy titanium, and tetrabutoxy titanium. Examples of the aluminum alkoxide include aluminum triisopropoxide, aluminum triethoxide, and the like. Can be mentioned.

  The solvent in the composition (3) is preferably a water-soluble organic solvent, for example, alcohols such as methyl alcohol and ethyl alcohol, ketones such as acetone and methyl ethyl ketone, cyclic ethers such as dioxane and tetrahydrofuran, N-methylpyrrolidone, dimethyl sulfone. Solvent agents such as oxide, dimethylformamide, dimethylacetamide, methylformamide, and methylacetamide. Among these, solvents such as cyclic ethers such as dioxane and tetrahydrofuran, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, methylformamide, and methylacetamide are preferable in view of preservation of alkoxysilane, film formation, and heat dissipation effect.

The amount of colloidal silica (solid content) in the composition (3) is 100 parts by weight of alkoxysilane in consideration of hydrolysis of alkoxysilane, film formability, film retention and heat dissipation, and heat shielding properties. 1 to 100 parts by weight, and more preferably 50 to 100 parts by weight.
Examples of the specific metal compound in the composition (3) include the same metal oxides as those used in the composition (1), and these hydroxides and nitrides can be used in combination. As the metal oxide, at least one of kaolin, silicon oxide, and aluminum oxide is preferable.

  Although the shape at the time of the addition of the metal compound of the composition (3) is not particularly limited, it is preferably used in the form of powder, preferably fine powder. This is because when the fine powder is used, the denseness of the obtained coating film is improved, and the heat resistance, heat dissipation, and mechanical strength of the coating film can be further improved.

  The particle diameter of the metal compound fine powder is preferably in the range of 80 nm to 30 μm, and more preferably in the range of 200 nm to 10 μm, in terms of average particle diameter.

  The sum of the amounts of silicon oxide powder and aluminum oxide powder is preferably 50 to 1000 parts by weight with respect to 100 parts by weight of alkoxysilane. The amount of kaolin is preferably 50 to 1000 parts by weight with respect to 100 parts by weight of alkoxysilane in consideration of film forming properties, high heat dissipation performance, and heat shielding performance.

  As the liquid phase in the composition (3), a commercially available alkoxysilane solution and colloidal silica aqueous dispersion prepared in advance can be used. For example, an equivalent mixed solution of TSB two-component WB300A / WB300B can be used.

  The compounding amount of the titanium alkoxide and / or aluminum alkoxide in the composition (3) is preferably added at a ratio of 0.01 to 0.5 of titanium and / or aluminum atoms with respect to the silicon atoms of the alkoxysilane. Titanium alkoxide and / or aluminum alkoxide may be added in advance to alkoxysilane or other components in the absence of water, or may be added simultaneously when mixing alkoxysilane and other components. it can.

  The composition (3) preferably contains 40 to 70% by weight of the liquid phase and 60 to 30% by weight of the metal oxide, and contains 45 to 55% by weight of the liquid phase and 55 to 45% by weight of the metal oxide. Is more preferable. When the metal oxide is in the form of fine powder, the compounding amount of the metal oxide can be less than the above range.

  The thickness of the heat dissipation film of the compositions (1), (2), and (3) is 10 to 150 μm, preferably 20 to 80 μm, as a solid after drying. As a method for forming the heat dissipation film, a spraying method such as spraying, a coating method such as roll coating, a printing method such as screen printing, and the like can be used, but the method is not limited to these methods. Absent.

  The liquid composition formed may be dried by heating at room temperature or in a drying furnace, or by hot air such as a dryer. When performing the heat drying process, it is necessary that the temperature is within the range of the maximum temperature or lower than the heat resistance temperature of the cell, and is performed at 300 ° C or lower.

From the viewpoint of heat dissipation characteristics, the composition 2 is most preferable, and the emissivity of 90% or more is exhibited in a specific energy peak wavelength region, and then the composition 1 is preferable.
The predetermined heat dissipation of the heat dissipation film obtained from these compositions means a characteristic that has a cooling effect even better than the cooling effect of the heat dissipation layer of the solar cell module that is currently used mainly industrially. The cooling effect is obtained by emitting far infrared rays.

  In the heat dissipation film of the present invention, the energy peak wavelength of the far infrared ray to be emitted (radiated) is a region of 7.2 to 9.0 μm, and the emissivity of this region is 70% or more.

Examples of the film having weather resistance include polyethylene (manufactured by Achilles) and polyolefin resin sheet (ZF14-100 manufactured by Nippon Zeon Co., Ltd.), etc., which have good far infrared transmission efficiency and predetermined weather resistance. If there is, it is not limited to these.
Polyethylene is particularly preferred.

  Next, the following can also be used as an overcoat material having weather resistance.

  Inorganic coating material Glasca HPC406H (trade name, manufactured by JSR Corporation), organic / inorganic hybrid coating material Grasca HPC 7506 (trade name, manufactured by JSR Corporation), silicone rubber coating material KE3402 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) Although it has a coating film, etc., it has a predetermined weather resistance and efficiently absorbs far-infrared rays in an energy peak wavelength range of 7.2 μm to 9.0 μm emitted from the heat dissipation film and radiates it to the other surface. If it is an overcoat material, it will not be restricted to these.

  The solar cell module heat dissipation film according to the present invention emits far-infrared rays due to temperature rise due to light reception of the cell and lowers the temperature of the cell. Therefore, as is clear from the experimental examples described later, the cell temperature is sufficiently high. Can be reduced.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows a first embodiment of a solar cell module according to the present invention. The solar cell module 10 shown in the figure includes a translucent surface cover 12 and a cell 14 having one surface fixed to one surface of the surface cover 12.

  The front cover 12 is made of, for example, a transparent glass plate or various synthetic resin plates, and has a predetermined translucency.

  One side of the cell 14 is fixed to the back side of the front cover 12 via the adhesive layer 16. The adhesive layer 16 has a light-transmitting property equivalent to that of the front cover 12, and, for example, EVA resin is used.

  A heat dissipation film 18 is provided on the other surface of the cell 14. In the case of the present embodiment, the heat dissipation film 18 is formed over the entire surface of the cell 14. The heat dissipation film 18 emits far-infrared rays when the temperature rises, and lowers the temperature of the cell that is the temperature rise source.

  For the heat dissipation film 18, the following three types of compositions, Composition 1, Composition 2, and Composition 3 were prepared.

[Synthesis Example 1]
29.2% by weight of a sodium silicate aqueous solution (Nippon Chemical Industry Co., Ltd. J sodium silicate No. 1), 29.2% by weight of a potassium silicate aqueous solution (2K potassium silicate manufactured by Nippon Chemical Industry Co., Ltd.), 41.6% by weight of pure water was mixed and sufficiently stirred to prepare an aqueous alkali metal silicate solution. In this alkali metal silicate aqueous solution, while stirring, 14.4 parts by weight of oxidized varnish, 19.4 parts by weight of silicon dioxide, 68.1 parts by weight with respect to 48.1 parts by weight of alkali metal silicate aqueous solution, 7 parts by weight of kaolin and 11.4 parts by weight of aluminum oxide metal oxide powder were added. The mixed solution was stirred until the powder was uniformly dispersed, and the number of rotations of stirring was further increased, and stirring was continued to obtain a composition 1 corresponding to the above-described composition (1).

[Synthesis Example 2]
Silicone resin emulsion (Shin-Etsu Chemical Co., Ltd. product “POLON-MF-56”) 50.8 parts by weight, kaolin 12 parts by weight, silicon oxide 8.2 parts by weight, aluminum oxide 12.3 parts by weight, titanium oxide 6.2 parts by weight and 10.5 parts by weight of zirconium oxide were added and stirred until the powder was uniformly dispersed, and then the stirring was continued for 40 minutes at a rotational speed of 1000 to 1200 rpm to obtain composition (2). The composition 2 corresponding to was obtained.

[Synthesis Example 3]
A solution was prepared by dissolving 300 parts by weight of methyltrimethoxysilane, 170 parts by weight of dimethyldimethoxysilane, 30 parts by weight of glycidoxypropyltrimethoxysilane, and 15 parts by weight of tetrabutoxytitanium in 485 parts by weight of N-methylpyrrolidone. The solution was mixed with 1000 parts by weight of an aqueous dispersion of 20% by weight acidic colloidal silica as a silica solid content. Take 700 parts by weight of this mixed solution, add 110 parts by weight of kaolin, 435 parts by weight of silicon oxide powder, 190 parts by weight of aluminum oxide powder, and 120 parts by weight of zirconium oxide powder, and stir and mix in the same manner as in Synthesis Example 1. A composition 3 corresponding to the product (3) was obtained.

  FIG. 8 shows [Embodiment 2] of the solar cell module according to the present invention, and the same or corresponding parts as those in [Embodiment 1] are denoted by corresponding reference numerals and the description thereof is omitted. Only the feature points will be described below.

  The solar cell module 10a shown in the figure includes a translucent surface cover 12a and a cell 14a having one surface fixed to one surface of the surface cover 12a. On the other surface of the cell 14a, a heat radiation film 18a is formed over the entire surface.

  The heat dissipating film 18a of this embodiment has a predetermined heat dissipating property and weather resistance, and is made of a single film spray paint. The radiation film 18a can be obtained as follows.

  An alkoxysilane mixture composed of 29 parts of dimethyldimethoxysilane, 57 parts of methyltrimethoxysilane and 14 parts of alkoxysilane containing an epoxy group (see Chemical formula 4) is mixed in 14.5 parts of pure water and 1.5 parts of acetic acid. A silane oligomer that was dropped and reacted at room temperature to be partially hydrolyzed was obtained. To this oligomer, 29 parts of diacetone alcohol was added to obtain an oligomer solution. From this organic solvent solution consisting of methanol and diacetone alcohol, 20% of the total was removed, and ethyl carbitol having the same weight as that of the solvent removed was added to this solution, and the partial hydrolyzate of the silane oligomer was removed. Obtained.

  The amount of ethyl carbitol added was 45% by weight in solid content after the silane oligomer partial hydrolyzate was dried at 105 ° C. for 120 minutes. Subsequently, 240 g of potassium hexatitanate fibers (fibers having an average diameter of 0.5 μm and an average length of 15 μm) are added to 1000 g of the organic solvent solution of the partially hydrolyzed silane compound, and alumina powder ( 500 g of an average particle size of 2.0 μm), 50 g of fumed silica powder (the average particle size of the primary particles is 7 nm and surface-treated with hexamethyldisilazane), N of Hercules, USA -30 type ethylcellulose powder 30g was added, and it stirred with the stirring tank which has a propeller type stirring blade for 30 minutes at liquid temperature 20-30 degreeC.

  Next, this mixed solution was transferred to a ball mill and mixed for 120 minutes. The liquid temperature during mixing was controlled to be 20 ° C to 30 ° C. Defoaming was easy during the ball mill. To the mixed solution taken out from the ball mill, a 50 wt% solution of tetracarboxytitanium ethyl carbitol is added in an amount of 20 parts by weight with respect to 100 parts by weight of the partially hydrolyzed silane compound, and the mixture is stirred at 25 ° C. for 15 minutes. By mixing, a liquid heat radiation composition 4 was obtained.

  The heat dissipation film 18a of this example has good heat dissipation characteristics, as is apparent from the results of the heat dissipation test 2 described later. Moreover, the heat dissipation film 18a of the present Example confirmed favorable weather resistance by the following tests.

Boiling resistance test The heat radiation film 18a formed on the surface-roughened copper plate is immersed in boiling water for 2 hours, and then taken out and immersed in cold water for 22 hours. After repeating this four times, it was dried and the appearance, peeling of the film with cello tape (registered trademark), and pencil hardness were confirmed. As a result, the appearance was free from cracks and peeling, and the pencil hardness was 6H or higher.

High temperature and high humidity resistance test Heat radiation film 18a formed on a roughened copper plate was left in a test bath at 60 ° C / 90% relative humidity for 2000 hours, taken out, dried, and then subjected to appearance and cello tape (registered trademark). The film peeling was confirmed. As a result, no cracks or peeling were observed.

Acid resistance test The heat dissipation film 18a formed on the surface-roughened copper plate was immersed in a 0.5% sulfuric acid aqueous solution at 30 ° C for 10 minutes, washed with water, dried, and then subjected to appearance and cello tape (registered trademark). The film peeling and pencil hardness were confirmed. As a result, there was no crack or peeling with respect to peeling of the film with the appearance cello tape (registered trademark), and a pencil hardness of 6H or more was obtained.

Salt water spray test Heat-dissipating film 18a formed on a roughened copper plate was sprayed with 35% 5% saline solution for 96 hours, washed with water and dried, then visually observed and a film using cello tape (registered trademark). The peeling and pencil hardness were observed. As a result, the appearance was free from cracks and peeling, and the pencil hardness was 6H or higher.

Thermal shock test Heat-radiation film 18a formed on a roughened copper plate was treated with -65 ° C. (30 minutes) to 125 ° C. (30 minutes) for 200 cycles, and then visually observed with cello tape (registered trademark). The film peeling was observed. As a result, there was no crack or peeling with respect to the appearance.

  The obtained compositions 1 to 4 were applied to a film thickness of 60 μm after drying on an aluminum plate, and dried under drying conditions suitable for each to prepare a coating film. Then, the surface opposite to the surface on which the coating film is formed is heated using a gas burner or the like to obtain a predetermined temperature, and the far infrared ray amount per unit area emitted from the opposite surface at that temperature is measured with an emissometer. did.

  The radiance and emissivity were measured at wavelengths of 0 to 25 μm (or 15 μm) at each measurement temperature (50 ° C., 100 ° C., 150 ° C., etc.). Here, the emissivity is a value indicating the amount of radiation (radiation) of the sample as a relative intensity with a complete black body as 1.0.

  For example, the emissivity of an aluminum rough surface (25.5 ° C.) is 0.055, the emissivity of a copper glossy surface (22 ° C.) is 0.072, and the emissivity (100 of a chromium nickel alloy polished surface). ° C) is 0.059.

As is apparent from FIGS. 2 to 7, the compositions 1 to 4 constituting the heat radiation films 18 and 18 a have a peak particularly in the region of 7.2 to 9.0 μm. % Emissivity was confirmed to be obtained.
A heat dissipation effect can be obtained in a region where the cell temperature of the solar cell module is 50 ° C to 130 ° C.

  FIG. 9 shows [Embodiment 3] of the solar cell module according to the present invention, and the same or corresponding parts as those in [Embodiment 1] are denoted by corresponding reference numerals and the description thereof is omitted. Only the characteristic points will be described below.

  The solar cell module 10b shown in the figure includes a translucent surface cover 12b and a cell 14b having one surface fixed to one surface of the surface cover 12b.

  On the other surface of the cell 14b, as in [Example 1], a heat radiation film 18b is formed over the entire surface.

  In the case of this example, the composition 2 of [Example 1] was used as the heat dissipation film 18b. A weather-resistant film or an overcoat material 22b is provided on the back side of the heat dissipation film 18b.

  In this example, a polyethylene film (manufactured by Achilles Co., Ltd.) thickness of 30 μm, a polyolefin-based resin film (ZF14-100 manufactured by Nippon Zeon Co., Ltd.) thickness of 50 μm, and an EVA film (containing a peroxide) of 100 μm are used as comparative examples. did.

Far-infrared transmission test This is a test of a single film, and the transmittance with respect to the wavelength at 1 to 15 μm was measured. The test results are shown in FIGS. FIG. 10 shows the transmittance of polyethylene, which shows that 73 to 90% of light is transmitted in a wavelength region of 7.2 to 9 μm. FIG. 11 shows the transmittance of the polyolefin-based resin sheet, and it can be seen that 28 to 70% of light is transmitted in a wavelength region of 7.2 to 9 μm.

  As a comparative example, FIG. 12 shows an EVA resin film, but it can be seen that it does not transmit at all in the wavelength region of 7.2 to 9 μm. The composition 2 was applied to an aluminum plate so as to have a film thickness of 60 μm after drying, and was dried under appropriate drying conditions.

  As a method of providing these films on the back surface side of the heat dissipation film 18b, the periphery of the four surfaces on the upper surface of the heat dissipation film was simply fixed with an adhesive tape without using an adhesive or the like.

  A coating film of Glasca HPC406H (trade name, manufactured by JSR Corporation), Glasca HPC 7506 (trade name, manufactured by JSR Corporation), silicone rubber coating material KE3402 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), or the like can be used.

  These overcoat materials do not transmit far infrared rays, but can absorb the emitted far infrared rays and radiate themselves to diffuse the heat to the outside and reinforce the weather resistance of the heat dissipation film 18b. can do.

  Using a white tempered glass for the surface cover, using a crystalline silicon solar cell element as a cell, and a solar cell module with EVA as an adhesive between the surface cover and the cell, the cell surface opposite to the light receiving side ( The composition 2 was applied on the back surface to a thickness of 60 μm after drying by heating and dried to obtain a heat dissipation film. An inorganic coating agent was laminated as an overcoat material on the heat dissipation film to produce a solar cell module sample having a cross-sectional structure shown in FIG.

  A solar cell module sample was installed outdoors, and solar power was generated to measure the temperature rise during operation. As a comparative sample, a comparative example module sample in which EVA was laminated on a heat dissipation film instead of the overcoat material was produced.

  The temperature of the solar cell module sample having the structure of the present invention was about 60 ° C. at the time of photovoltaic power generation (during operation). The temperatures were as low as 52 ° C. and 8 ° C., indicating a significant radiation cooling effect.

The heat radiation characteristics of the laminate of the heat radiation films 18, 18a, 18b and the overcoat material 22b of the present invention were performed by the following four tests.
Heat dissipation test 1

  The composition 2 was applied to the outside of the wall surface of an aluminum cylindrical can having a diameter of 50 mm and a height of 77 mm so as to have a thickness of 60 μm after drying by heating, allowed to stand at room temperature for 1 hour, and then dried at 120 ° C. for 15 minutes. 1 was produced.

  A sample 2 was prepared by winding a polyethylene film (thickness 50 μm, manufactured by Achilles) around the outer side of the sample 1.

  Further, an EVA film (thickness: 100 μm) was wound around the outer side of the sample 1 to prepare a sample 3.

  Then, hot water of 95 ° C. or more is poured into each sample 1 to 3 (inside an aluminum cylindrical can having a diameter of 50 mm × height of 77 mm) and left in an external atmosphere (room temperature) to obtain an initial hot water temperature of 93.4 ° C. However, the time required for the temperature to decrease to 60 ° C. (temperature decrease time) was measured.

  The temperature was measured using a Hioki Memory Hilogger 8420. The measured temperature decrease curve is shown in FIG. These are a temperature decrease curve of Sample 1, a temperature decrease curve of Sample 2, a temperature decrease curve of Sample Example 3, and a temperature decrease curve of an aluminum cylindrical can that has not been subjected to any treatment. FIG. 14 is a partially enlarged view of the curve around the temperature of 60 ° C. in the temperature decrease curve of FIG.

  Table 1 shows the time required for the initial hot water temperature to drop from 93.4 ° C. to 60 ° C. (temperature reduction time).

  As is clear from Table 1, Sample 1 and Sample 2 were significantly better in heat dissipation than the blank. In addition, the sample 1 in which only the composition 2 is applied to the blank and the sample 2 in which polyethylene is laminated have the same temperature reduction time, so that the structure having a film that transmits far-infrared rays by radiation has a heat dissipation property. It turns out that it is excellent.

  On the other hand, in Sample 3 in which an EVA film that does not transmit far-infrared rays by radiation is laminated on Composition 2, the temperature drop time is longer than either Sample 1 or Sample 2, and it is found that the heat dissipation is inferior.

Thermal test 2
In the same manner as in the heat release test 1, on the outside of the wall surface of an aluminum cylindrical can having a diameter of 50 mm and a height of 77 mm, the composition 4 (single film spray coating) of [Example 2] is heated and dried to a thickness of 60 μm. Then, the sample 4 was allowed to stand at room temperature for 3 hours and then slowly dried with a temperature profile up to 180 ° C. to prepare Sample 4.

  In addition, in this test, for comparison, an aluminum can blank of the same size (sample 5) having a heat radiation film formed of the composition 2 of [Example 1] and an aluminum base blank were prepared.

  Then, hot water of 95 ° C. or more is put inside each sample (inside an aluminum can having a diameter of 50 mm × height of 77 mm) and left in an external atmosphere (room temperature), and the initial hot water temperature of 93.4 ° C. is 50 ° C. The time required for the temperature to drop to (temperature drop time) was measured.

  The temperature was measured using a Hioki Memory Hilogger 8420. The measured temperature decrease curve is shown in FIG. These are the temperature decrease curve of sample 4, the temperature decrease curve of sample 5, and the temperature decrease curve of an aluminum can that has not been subjected to any treatment. FIG. 16 is a partially enlarged view of the curve around the temperature of 50 ° C. in the temperature decrease curve of FIG.

  Table 2 shows the time required for the initial hot water temperature to drop from 93.4 ° C. to 50 ° C. (temperature reduction time).

  As is apparent from the results shown in FIGS. 18 and 19, the heat dissipation film 18a made of the composition 4 of [Example 2] also has the same heat dissipation characteristics as the composition 2 of [Example 1].

Heat dissipation test 3
The composition 2 of [Example 1] was applied to the outside of the wall surface of an aluminum cylindrical can having a diameter of 50 mm and a height of 77 mm so as to have a thickness of 60 μm after drying by heating, left at room temperature for 1 hour, and then 15 ° C. at 15 ° C. The sample 6 was produced by partial drying.

  Further, Glaska HPC7506 (manufactured by JSR Corporation, trade name) was applied to the outer side of sample 6 to prepare sample 7.

  Further, a silicone rubber coating material KE3402 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the outer side of the sample 6 to prepare a sample 8.

  Then, hot water of 95 ° C. or more is put inside each sample 6 to 8 (inside an aluminum cylindrical can having a diameter of 50 mm and a height of 77 mm) (sample 5 is an aluminum cylindrical can having no surface treatment). Then, it was left in an external atmosphere (room temperature), and the time required for the initial hot water temperature 93.4 ° C. to drop to 60 ° C. (temperature reduction time) was measured.

  The temperature was measured using a Hioki Memory Hilogger 8420. The measured temperature decrease curve is shown in FIG. These are a temperature decrease curve of sample 6, a temperature decrease curve of sample 7, a temperature decrease curve of sample 8, and a temperature decrease curve of an aluminum cylindrical can that has not been subjected to any treatment. FIG. 18 is a partially enlarged view of a curve around the temperature of 50 ° C. in the temperature decrease curve of FIG.

  Table 3 shows the time required for the initial hot water temperature to drop from 93.4 ° C. to 50 ° C. (temperature reduction time).

  As is clear from Table 3, Samples 6 to 8 were significantly better in heat dissipation than the blank. Moreover, since the sample 6 which apply | coated only the composition 2 to the blank and the samples 7-8 which absorb and radiate | emit far infrared rays are comparable, the overcoat which absorbs and radiates | emits far infrared rays is comparable. It turns out that the structure which has is excellent in heat dissipation.

Heat dissipation test 4
The composition 4 of [Example 2] was applied to the outside of the wall surface of an aluminum cylindrical can having a diameter of 50 mm and a height of 77 mm so as to have a thickness of 60 μm after heating and drying, and dried under appropriate drying conditions. 9 was produced.

  An EVA film (thickness: 100 μm) and a PET film (thickness: 30 μm), which are currently used as a back cover material, are wound around the outside of a wall surface of an aluminum cylindrical can having a diameter of 50 mm and a height of 77 mm. 10 was produced.

The EVA film was wound on the inside and the PET film was wound on the outside.
Then, hot water of 95 ° C. or more is poured into each sample 9 and 10 (inside an aluminum cylindrical can having a diameter of 50 mm × height of 77 mm) and left in an external atmosphere (room temperature) to obtain an initial hot water temperature of 93.4 ° C. However, the time required for the temperature to decrease to 60 ° C. (temperature decrease time) was measured.

  The temperature was measured using a Hioki Memory Hilogger 8420. The measured temperature decrease curve is shown in FIG. In the figure, there are a temperature decrease curve of Sample 9, a temperature decrease curve of Sample 10, and a temperature decrease curve of aluminum that is not subjected to anything. FIG. 20 is a partially enlarged view of the curve around the temperature of 60 ° C. in the temperature decrease curve of FIG.

  Table 4 shows the time required for the initial hot water temperature to drop from 93.4 ° C. to 50 ° C. (temperature reduction time).

  As is clear from Table 4, Sample 9 was significantly better in heat dissipation than Sample 10. It can be seen that the heat dissipation is excellent.

  The solar cell module heat dissipation film according to the present invention can be effectively used for energy saving and global warming prevention because a module with high photoelectric conversion efficiency can be obtained at low cost by effectively cooling the cell temperature. Can do.

It is sectional drawing which shows Example 1 of the solar cell module concerning this invention. It is a graph which shows the measurement result of the radiance and emissivity in 100 degreeC of the thermal radiation film | membrane (composition 1) of this invention. It is a graph which shows the measurement result of the radiance and emissivity in 50 degreeC of the thermal radiation film | membrane (composition 2) of this invention. It is a graph which shows the measurement result of the radiance and emissivity in 100 degreeC of the thermal radiation film | membrane (composition 2) of this invention. It is a graph which shows the measurement result of the radiance and emissivity in 150 degreeC of the thermal radiation film | membrane (composition 2) of this invention. It is a graph which shows the measurement result of the radiance and emissivity in 100 degreeC of the thermal radiation film | membrane (composition 3) of this invention. It is a graph which shows the measurement result of the radiance and emissivity in 100 degreeC of the thermal radiation film | membrane (composition 4) of this invention. It is sectional drawing which shows Example 2 of the solar cell module concerning this invention. It is sectional drawing which shows Example 3 of the solar cell module concerning this invention. It is a graph which shows the measurement result of the transmittance | permeability of the far infrared rays with respect to polyethylene. It is a graph which shows the measurement result of the transmittance | permeability of the far infrared rays with respect to polyolefin. It is a graph which shows the measurement result of the transmittance | permeability of the far infrared rays with respect to EVA resin. It is a temperature fall curve of the structure which provided the film in the heat dissipation film. It is a principal part enlarged view of FIG. It is a temperature fall curve of 1 film | membrane heat dissipation film (composition 4) which has a weather resistance. It is a principal part enlarged view of FIG. It is a temperature fall curve of the structure which provided the overcoat material in the heat dissipation film. It is a principal part enlarged view of FIG. It is a comparative temperature fall curve of 1 film | membrane heat radiating film (composition 4) which has a weather resistance, and a back sheet. It is a principal part enlarged view of FIG.

Explanation of symbols

10, 10a, 10b Solar cell module 12, 12a, 12b Surface cover 14, 14a, 14b Cell 16, 16a, 16b Adhesive layer 18, 18a, 18b Heat dissipation film
22b Weather-resistant film or weather-resistant overcoat material

Claims (10)

In a solar cell module comprising a translucent surface cover and a cell having one surface fixed to the surface cover,
A heat dissipation film provided on the other surface of the cell,
The heat radiation film has a cooling function of emitting far infrared rays and reducing the temperature rise of the cell when the cell receives light and rises in temperature.   The heat dissipation film for a solar cell module according to claim 1, wherein the heat dissipation film has both predetermined heat dissipation and weather resistance.   The heat dissipation film for a solar cell module according to claim 1 or 2, wherein the heat dissipation film is provided with a film having weather resistance on a radiation surface opened to the atmosphere side.   The heat dissipation film for a solar cell module according to claim 1, wherein the heat dissipation film is provided with an overcoat material having weather resistance on a radiation surface opened to the atmosphere side.   5. The solar cell module heat dissipation film according to claim 1, wherein the far infrared rays emitted from the heat dissipation film have an emissivity of 70% or more in a specific energy peak wavelength region.   4. The solar cell module heat radiation film according to claim 3, wherein the film transmits far infrared rays having a wavelength of 4 to 15 [mu] m, which is a wavelength necessary for heat radiation.   The solar cell module heat dissipation film according to claim 6, wherein the overcoat material absorbs and radiates the far infrared rays.   3. The heat dissipation film is formed from a composition in which a specific metal compound is contained in a liquid material composed of a partially hydrolyzed product of an alkoxysilane compound, alkoxytitanium and an organic solvent. Heat dissipation film for solar cell module.   The heat dissipation film is formed from a composition containing a specific metal compound in a liquid material including any one of a specific alkali metal silicate, a silicone resin emulsion, and a silane compound. The heat dissipation film for solar cell modules according to claim 3 or 4. The solar cell module provided with the thermal radiation film of any one of Claims 2-9.

Images