JPH06140657A - Solar cell - Google Patents

Abstract

PURPOSE:To reduce a weight, improve moisture permeability proofness and reduce a cost. CONSTITUTION:A plurality or solar cell modules 1 are provided on a rigid plate 10 so as to have their interstices filled with sealing material 2 and the surface of the sealing material 2 is covered with a film 11 to compose a solar cell. An inorganic coating layer 12 made of ceramic precursor is formed on the film 11 and an organic coating layer 13 is applied to the inorganic coating layer 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention aims to reduce the weight and
The present invention relates to a solar cell having improved moisture resistance.

[0002]

2. Description of the Related Art In a conventional solar battery panel, a plurality of solar battery cells 1 connected in series as shown in FIG. The surroundings are fixed by a structural member 4 consisting of, and are supported by a dedicated pedestal 5, and attached at a predetermined position.

In such a solar cell, a glass plate 3 which is rigid and has a supporting force and is transparent and which is transparent is used on the surface. When the area is large, the glass plate is easily broken. Therefore, generally, tempered glass is used. ing. This tempered glass is very heavy, and it takes 6-7% of the whole solar cell module.
It is relatively expensive and expensive.

As a countermeasure against this, a compound M (OR) n called a metal alcoholate in which carbon or oxygen is bonded to a metal is used as a main component, and the metal alcoholate is subjected to hydrolysis and polycondensation reaction in the presence of water, alcohol and a catalyst. It has been proposed to raise it to form a sol first, and then to form a gel by heating, heat this gel to form an amorphous transparent ceramic film, and use this ceramic coating film as a support substrate. Sho 61-11116
No. 2).

[0005]

However, in the above proposal, the ceramic coating film is produced by the sol-gel method, and the ceramicizing temperature is usually 300 to 35.
The temperature is as high as 0 ° C or 500 ° C or higher. However, the solar cell panel is filled with an encapsulant such as EVA (ethylene vinyl acetate) and cannot be used because the encapsulant melts and decomposes at such a high ceramicizing temperature.

As a measure for reducing the weight, it is possible to reduce the weight by providing a support plate made of plastic or the like on the back surface and film-coating the surface, but the film alone has water permeability and is deteriorated by light. There was a problem of being lost.

The present invention is intended to solve the above problems, and an object of the present invention is to provide a solar cell which can be reduced in weight, improved in moisture permeation resistance, and reduced in cost.

[0008]

DISCLOSURE OF THE INVENTION The present invention is a solar cell in which a plurality of solar cell modules are arranged by filling a sealant on a rigid plate, and the surface of the solar cell module is covered with a film. It is characterized in that an inorganic coat layer made of a ceramic precursor is coated, and an organic coat layer is coated on the inorganic coat layer.

As the ceramic precursor, various conventionally known polysilazanes can be used, but the following polysilazanes are preferable.

General formula (1)

[0011]

[Chemical 3]

Having a number average molecular weight of 1 having a repeating unit of
00-50,000 cyclic inorganic polysilazane, chain inorganic polysilazane or a mixture thereof (JP-A-59-207)
812).

As a raw material, the polysilazane or A. Stock, Ber, 54, P740 (192
1), W. M. Scanlim, Inorganic
Chemistry, 11 (1972), A.S. Seey
Ferth, U.S. Pat. No. 4,397,328, and other silazane polymers can be used to prepare tertiary amines such as trialkylamines, secondary amines having sterically hindering groups, phosphine and the like. A number average molecular weight of 200 to 50 obtained by using a basic compound as a solvent or adding it to a non-basic solvent, for example, hydrocarbons and heating at -78 ° C to 300 ° C to carry out a dehydrogenative condensation reaction.
A high polymer of 50,000, preferably 500 to 100,000 (JP-A-1-138108).

A polymer obtained by an improved reaction of an inorganic polysilazane, which has a cross-linking bond —NH— or —NH—NH— and has an atomic ratio of nitrogen bonded to a silicon atom and silicon (N
/ Si) is 0.8 or more and the number average molecular weight is 200 to 50.
50,000, preferably 500 to 100,000. This modified polysilazane can be produced by carrying out a dehydrogenative condensation reaction of polysilazane using ammonia or hydrazine (JP-A-1-13810).
No. 7).

Compositional formula (RSiHNH) _x [(RSiH) _1.5 N] _y (wherein R represents an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, or an atom other than these groups, which is directly bonded to Si. A polyorganohydrosilazane represented by a group that is carbon, an alkylsilyl group, an alkylamino group, an alkoxy group, y is 1-x, and 0.4 <x <1 (Japanese Patent Laid-Open No. 62-62). 156135
issue).

Furthermore, polysiloxazane containing oxygen (JP-A-62-195024) and polymetallosilazane obtained by reacting a metal alkoxide (JP-A-2-774).
No. 27), polyborosilazane obtained by reacting an organic boron compound (JP-A-2-84437) and the like can also be used. The above-mentioned various polysilazanes are liquid to solid at room temperature depending on the type.

It is preferable to use polysilazane having a high content of active hydrogen, which is directly connected to silicon or nitrogen, from the viewpoint of adhesiveness to the resin. Generally, the total number of silicon atoms and nitrogen atoms is 100. On the other hand, it is advantageous to use those having 90 or more, preferably 100 to 152, active hydrogen atoms.

In order to produce a resin-formed product having a cured film of polysilazane, the above polysilazane is used as a coating material, the surface of the resin-formed product is coated, and a polysilazane film is formed on the surface of the resin, followed by heating. Treatment or electron beam treatment. If the polysilazane is liquid, after coating the resin surface with air, an inert gas (for example, N ₂ , argon, etc.),
In a reducing gas (for example, ammonia, hydrazine, etc.) or vacuum atmosphere, the temperature is maintained between room temperature and the melting point or decomposition point of the resin, usually at a temperature of 80 to 200 ° C. for a certain period of time. This gives a coating of solid crosslinked polysilazane. If the polysilazane is solid (powdered), dissolve it in an organic solvent, coat this solution on the surface of the resin, and evaporate and remove the used organic solvent to form a solid polysilazane film. You can

Coating materials containing polysilazane include organic amines, carboxylic acid anhydrides, isocyanates,
Hardeners such as thiols, carboximides, metal alkoxides and metal hagerone compounds can be added, and metal powders and ceramic powders, such as metal nitrides, oxides, and carbides can also be added in a fixed amount, Furthermore, an appropriate amount of aluminum titanate or silicon resin can be added.

The heat treatment of the polysilazane film is carried out at a temperature of 100 ° C. or higher in the atmosphere of air, inert gas, reducing gas or vacuum mentioned above. In this case, the rate of temperature rise is 100 ° C./min or less, preferably 20 ° C./min or less. The upper limit of the heating temperature is the melting point or decomposition point of the resin. The heat treatment converts the polysilazane coating into a cured coating.

The characteristics of the polysilazane used in the present invention will be described. Generally, when the polysilazane is heat-treated in an air or oxygen atmosphere, the condensation or decomposition of the polysilazane is promoted by the action of oxygen, and the temperature is 100 to 300. ℃
A moderate heating produces a hardened body containing hydrogen and / or carbon, and a heating above about 300 ° C. forms a ceramic substantially free of hydrogen and carbon. On the other hand, in heating under an inert gas or a reducing atmosphere, 100 to 500 ° C
By heating to a certain degree, dehydrogenative condensation of polysilazane mainly occurs, and a hardened body containing hydrogen and / or carbon is produced, and at a temperature higher than that, polysilazane mainly decomposes and a ceramic is formed.

As the resin constituting the resin-formed product, one having a softening point of 100 ° C. or higher, preferably 130 ° C. or higher is used. Examples of such resin include polycarbonate, polyimide, phenol resin, polyether ether ketone, polybutylene terephthalate, polyether sulfone, polyphenylene ether, polyphenylene sulfide, epoxy resin, nylon, polypropylene and the like.

In the case of subjecting polysilazane to electron beam treatment, the electron beam generator is, for example, I-Electron Beam ELECTROCURTAIN TYPE: C.
B175 / 15 / 180L or the like is used.

As a method for forming the polysilazane film on the surface of the resin formed body, various conventionally known coating methods, for example, a dipping method, a spray method and the like can be mentioned. Also,
A method of thermocompression-bonding a preformed polysilazane film on the surface of the resin formed body can also be adopted.

As a method of obtaining a resin-formed product having a cured film of polysilazane, a resin sheet having a film of polysilazane is used as a forming material, which is processed into a desired shape and then heat-treated or electron beam-treated, or polysilazane. There is a method in which a resin sheet having a coating film is subjected to heat treatment or electron beam treatment and then processed into a desired shape. Considering the processability of the coating, it is preferable to heat the resin sheet having the polysilazane coating into a desired shape and then subject it to heat treatment or electron beam treatment.

The polysilazane used as the coating material in the present invention is very excellent in adhesiveness to the resin because the hydrogen atom bonded to the silicon atom or the nitrogen atom acts as active hydrogen. In addition, the polysilazane cured by heat treatment or electron beam treatment has a very high adhesion strength with respect to the resin, and gives a coating having excellent durability.

The polysilazane used in the present invention is dehydrogenated and condensed by the heat treatment and the electron beam treatment to be crosslinked to form a hard cured product, and finally to a ceramic. Therefore, the properties of the coating film on the resin surface can be adjusted by the conditions of the heat treatment and electron beam treatment. In order to obtain a cured coating having excellent heat resistance, corrosion resistance, abrasion resistance, and scratch resistance, a coating having a hydrogen or carbon content as small as possible, for example, a total content of hydrogen and carbon of 5% by weight or less, preferably A coating of 0.2 to 2% by weight is preferable. The thickness of the cured film is usually 0.1 to 100 μm, preferably 0.5.
˜50 μm.

The above-mentioned cured film of polysilazane has little shrinkage, extremely few cracks, and is dense, and therefore has almost no pinholes.

Further, it is possible to more suitably use the modified polysilazane having a lower ceramization temperature. In the modified polysilazane, by adding glycidol to the polysilazane, the curing reaction when the coating film of the addition product is fired in air is promoted, and a good coating is formed at a firing temperature lower than conventional ones.

The modified polysilazane is mainly represented by the general formula (2):

[0031]

[Chemical 4]

(However, R ¹ , R ² , and R ³ are each independently a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, or a group other than these groups in which the group directly bonded to silicon is carbon. , An alkylsilyl group, an alkylamino group, and an alkoxy group, and at least one of R ¹ , R ² , and R ³ is a hydrogen atom) having a main skeleton composed of units represented by A coating composition containing at least a glycidol-added polysilazane having a glycidol / polysilazane weight ratio in the range of 0.001 to 2 and a number average molecular weight of about 200 to 500,000, obtained by reacting 50,000 polysilazanes with glycidol. is there.

The glycidol-added polysilazane used as an essential component of the coating composition is such that the hydrogen atoms bonded to at least a part of silicon atoms in the entire skeleton of polysilazane react with glycidol, and the silicon atoms in polysilazane react with glycidol. It is a compound having a condensed side chain group or a cyclic or crosslinked structure.

In the reaction between polysilazane and glycidol, a dehydrogenative condensation reaction occurs between the OH group of glycidol and the SiH group of polysilazane to form a Si-O-C bond.

Further, depending on the reaction conditions, a bond is formed between the carbon at the 3-position or 2-position of glycidol and the NH group of polysilazane to open the epoxy group, and the OH group thus generated and the SiH group of polysilazane are generated. In some cases, a dehydrogenative condensation reaction may occur between them to form a Si—O—C bond. In this case, a crosslinked structure is formed between the polysilazane molecules via the glycidol molecule.

The method for producing the glycidol-added polysilazane used in the present invention comprises reacting polysilazane and glycidol with or without a solvent and in an atmosphere inert to the reaction.

The polysilazane to be used may be any polysilazane having at least a Si--H bond or an N--H bond in the molecule. Not only polysilazane alone, but also a copolymer of polysilazane and another polymer or polysilazane and other It can also be used as a mixture with the compound of.

The polysilazanes to be used include those having a chain structure, a cyclic structure, or a cross-linking structure, or those having a plurality of these structures simultaneously in the molecule, and these can be used alone or in a mixture.

The following are typical examples of polysilazanes to be used, but the polysilazanes are not limited to these.

The ^one having hydrogen atoms in R ¹ , R ² and R ³ in the general formula (2) is perhydropolysilazane, and the production method thereof is, for example, JP-A-60-145903, D. Seyferth et al. Communication of Am.Cer.Soc., C-1
3, January 1983. Has been reported to. What is obtained by these methods is a combination of polymers having various structures, but basically contains a chain portion and a cyclic portion in the molecule,

[0041]

[Chemical 5]

It can be represented by the chemical formula: An example of the structure of perhydropolysilazane is shown below.

[0043]

[Chemical 6]

In the general formula (2), R ¹ and R ² are hydrogen atoms,
The method for producing polysilazane having a methyl group in R ³ is described in D.
Seyferth et al. Polym.Prepr., Am.Chem.Soc., Div.Polym.Che
m, .25,10 (1984). The polysilazane obtained by this method has a repeating unit of −
(SiH ₂ NCH ₃₎ - is a chain polymer and a cyclic polymer, either no cross-linked structure.

In the general formula (2), R ¹ and R ² are hydrogen atoms,
A method for producing a polyorgano (hydro) silazane having an organic group in R ³ is described in D. Seyferth et al., Polym.Prepr., Am.Chem.Soc.,
Div. Polym. Chem., 25, 10 (1984), JP-A-61
-89230. The polysilazane obtained by these methods, - (R ² SiHNH) - as a repeating unit, and primarily a polymerization degree having a cyclic structure 3-5, also (R ³ SiHNH) _x [(R ²
SiH) _1.5 N] _1-x (0.4 <x <1) has a chain structure and a cyclic structure at the same time in the molecule.

In the general formula (2), polysilazane having a hydrogen atom for R ¹ and an organic group for R ² and R ³ , or R ¹ and R
Those having an organic group in ² and a hydrogen atom in R ³ are represented by-(R ¹
It has a cyclic structure mainly having a degree of polymerization of 3 to 5 with R ² SiNR ³ ) − as a repeating unit.

Among the polysilazanes used next, typical examples other than those of the general formula (2) will be given.

Among the polyorgano (hydro) silazanes are D. Seyferth et al. Communication of Am. Cer. Soc., C-1.
3 2, July 1984. There are also those having a cross-linked structure in the molecule as reported in. An example is as follows.

[0049]

[Chemical 7]

Further, polysilazane (R ¹ Si (NH) _x ) having a crosslinked structure obtained by ammonia decomposition of R ¹ SiX ₃ (X: halogen) as reported in JP-A-49-69717, Or R ¹ SiX ₃
And polysilazane having the following structure obtained by co-ammonia decomposition of R ² ₂ SiX ₂ can also be used as a starting material.

[0051]

[Chemical 8]

The polysilazane to be used has a main skeleton composed of the unit represented by the general formula (2) as described above, but the unit represented by the general formula (2) may be cyclized as is apparent from the above. In that case, the cyclic portion serves as a terminal group, and when such a cyclization is not carried out, the terminal of the main skeleton may be a group similar to R ¹ , R ² or R ³ or hydrogen.

There is no particular restriction on the molecular weight of the polysilazane to be used, and any available polysilazane can be used, but in view of reactivity with glycidol, R ¹ in the formula (2),
R ² and R ³ are preferably groups having small steric hindrance. That is, R ¹ , R ² and R ³ are hydrogen atoms and C _{1 to} C
The alkyl group of ₅ is preferable, and a hydrogen atom and a C _{1 to} C ₂ alkyl group are more preferable.

The mixing ratio of polysilazane and glycidol is such that the glycidol / polysilazane weight ratio is 0.001 to 2, preferably 0.01 to 1, and more preferably 0.05 to 0.5. To be added. If the amount of glycidol added is increased beyond this range, the molecular weight of polysilazane increases too much to cause gelation, and if it is too small, no sufficient effect can be obtained.

Although the reaction can be carried out without a solvent, it is generally preferable to use an organic solvent because the reaction restriction is more difficult and a gelled substance may be formed than when an organic solvent is used. As the solvent, aromatic hydrocarbons, aliphatic hydrocarbons, hydrocarbon solvents of alicyclic hydrocarbons, halogenated hydrocarbons, aliphatic ethers, alicyclic ethers, and aromatic amines can be used. Preferred solvents include, for example, benzene, toluene, xylene, methylene chloride, chloroform, n-hexane, ethyl ether, tetrahydrofuran, pyridine, methylpyridine and the like, and particularly preferred solvents include pyridine and methylpyridine. Also, an atmosphere inert to the reaction, such as nitrogen,
It is necessary to carry out the reaction in an atmosphere of argon or the like, and it is not preferable to carry out the reaction in an oxidizing atmosphere such as air because the raw material polysilazane and glycidol are oxidized or hydrolyzed.

The reaction temperature can be varied over a wide range. For example, when an organic solvent is used, it may be heated to a temperature below the boiling point of the organic solvent, but it is necessary to obtain a solid having a high number average molecular weight. Alternatively, the reaction can be carried out by subsequently heating the organic solvent to a boiling point or higher to distill off the organic solvent. The reaction temperature is generally preferably 150 ° C. or lower in order to prevent excessive ring opening of the epoxy group in glycidol and gelation of polysilazane due to it.

The reaction time is not particularly important, but usually 1 to
It is about 50 hours. It is generally preferable to carry out the reaction at around normal pressure. In the present invention, in order to prepare a coating composition using the glycidol-added polysilazane, usually, the glycidol-added polysilazane may be dissolved in a solvent.

Examples of the solvent include aliphatic hydrocarbons, alicyclic hydrocarbons, hydrocarbon solvents of aromatic hydrocarbons, halogenated hydrocarbons such as halogenated methane, halogenated ethane and halogenated benzenes, aliphatic ethers and fats. Ethers such as cyclic ethers can be used. Preferred solvents are halogenated hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, bromoform, ethylene chloride, ethylidene chloride, trichloroethane and tetrachloroethane, ethyl ether,
Ethers such as isopropyl ether, ethyl butyl ether, butyl ether, 1,2-dioxyethane, dioxane, dimethyldioxane, tetrahydrofuran, tetrahydropyran, pentane, hexane, isohexane, methylpentane, heptane, isoheptane, octane, isooctane, cyclopentane, methylcyclo Hydrocarbons such as pentane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, ethylbenzene and the like.

When using these solvents, two or more kinds of solvents may be mixed in order to adjust the solubility of the glycidol-added polysilazane and the evaporation rate of the solvent. The amount (ratio) of the solvent used is selected so as to improve the workability depending on the coating method adopted, and it depends on the average molecular weight, the molecular weight distribution, and the structure of the glycidol-added polysilazane.
It can be mixed up to about 10% by weight, preferably 10 to
It is possible to mix in the range of 50% by weight.

The solvent concentration varies depending on the average molecular weight of the glycidol-added polysilazane, the molecular weight distribution, and its structure, but good results are usually obtained within the range of 0 to 90% by weight.

Further, in the present invention, a suitable filler may be added if necessary. Examples of the filler include fine particles of oxide-based inorganic materials such as silica, alumina, zirconia and mica, or non-oxide-based inorganic materials such as silicon carbide and silicon nitride. Depending on the application, it is also possible to add metal powders such as aluminum, zinc and copper. More specifically, examples of fillers are silica-based materials such as silica sand, quartz, novaculite and diatomaceous earth: Synthetic amorphous silica: Kaolinite, mica, talc, wollastonite, asbestos, calcium silicate, aluminum silicate Silicates such as: Glass powder: Glass spheres, hollow glass spheres, glass flakes, foam glass spheres, etc .: Boron nitride, boron carbide, aluminum nitride, aluminum carbide, silicon nitride, silicon carbide, titanium boride, nitride Non-oxide inorganic substances such as titanium and titanium carbide: calcium carbonate: zinc oxide, alumina, magnesia, titanium oxide, beryllium oxide and other metal oxides: barium sulfide, molybdenum disulfide,
Tungsten disulfide, carbon fluoride, and other inorganic substances: metal powders such as aluminum, bronze, lead, stainless steel, zinc: carbon black, coke, graphite, pyrolytic carbon, carbon bodies such as hollow carbon spheres, and the like.

These fillers have various shapes such as needles (including whiskers), granules, and scales, either alone or in the form of 2
A mixture of two or more species can be used. Further, it is desirable that the particle size of these fillers is smaller than the film thickness that can be applied at one time. Further, the amount of the filler added is 0.05 parts by weight to 1 part by weight of the silicon alkoxide-added polysilazane.
It is in the range of 10 parts by weight, and a particularly preferable amount of addition is 0.2.
The range is 3 to 3 parts by weight. Further, the surface of the filler may be surface-treated by a coupling agent treatment, vapor deposition, plating or the like for use.

The coating composition may contain various pigments, leveling agents, defoaming agents, antistatic agents, ultraviolet absorbers, pH adjusters, dispersants, surface modifiers, plasticizers, and drying accelerators, if necessary. Alternatively, anti-flow agents may be added.

The coating composition of the present invention is obtained by repeatedly coating the above coating composition on a substrate once or twice or more, and then firing it to obtain silicon-nitrogen-oxygen system or silicon-nitrogen-oxygen-carbon system ceramics. It is performed by forming a coating film composed of.

Further, according to the present invention, the properties of the coating film can be improved by keeping the coating film fired as described above under the condition of less than 50 ° C. for a long time.

Further, in the present invention, after the coating composition as described above is repeatedly applied to the substrate once or twice or more, the coating film is kept at a temperature of less than 50 ° C. for a long time, and the silicon-
A coating film made of nitrogen-oxygen- or silicon-nitrogen-oxygen-carbon ceramics can be formed.

The substrate on which the coating composition is applied is not particularly limited and may be any of metal, ceramics, plastics and the like. As a coating means for coating, a usual coating method, that is, dipping, roll coating, bar coating, brush coating, spray coating, flow coating or the like is used. Further, if the substrate is sanded, degreased, and surface-treated with various blasts before coating, the adhesion performance of the coating composition is improved.

After coating by such a method and sufficiently dried, it is heated and baked. By this baking, the glycidol-added polysilazane is crosslinked, condensed, or oxidized and hydrolyzed in a baking atmosphere to be hardened to form a tough coating.

The above firing conditions vary depending on the molecular weight and structure of the glycidol-added polysilazane, but are 0.5-10 ° C /
Bake at a temperature in the range of 50 ° C. to 1000 ° C. at a moderate heating rate of a minute. The preferred firing temperature is in the range of 50 ° C to 300 ° C. The firing atmosphere may be in the air, an inert gas, or the like, but the air is more preferable. Oxidation of glycidol-added polysilazane by hydrolysis in air or hydrolysis by water vapor coexisting in air progresses, resulting in a tough coating mainly composed of SI-O bond or Si-N bond at the above low baking temperature. Can be formed.

Depending on the type of glycidol-added polysilazane to be coated, the conversion to ceramics may be incomplete under limited firing conditions. In this case, the coating film after firing may be treated at a temperature lower than 50 ° C. for a long time. Hold time,
It is possible to improve the properties of the coating film. In this case, the holding atmosphere is preferably air, and more preferably wet air having an increased water vapor pressure. The holding time is not particularly limited, but 10 minutes or more and 30 days or less is practically appropriate. The holding temperature is not particularly limited, but 0 ° C or more and less than 50 ° C is practically appropriate.
Of course, holding at 50 ° C or higher is also effective,
In the present invention, the heating operation at 50 ° C. or higher is defined as “baking”. That is, it is also effective to bake at a certain temperature for a certain period of time and then lower the temperature to, for example, 50 ° C. and bake for a long time.

By this holding in air, oxidation of glycidol-added polysilazane or hydrolysis by water vapor coexisting in air further progresses, conversion to ceramics is completed, and a tougher coating with improved properties is obtained. A covering film can be formed. According to the above method, the firing temperature can be lowered and various problems caused by the high firing temperature can be alleviated.

Further, depending on the type of the glycidol-added polysilazane to be coated, the coating film after coating is kept at a temperature of less than 50 ° C. for a long time without performing baking at 50 ° C. or higher at all. It is possible to improve. In this case, the holding atmosphere is preferably air, and more preferably wet air having an increased water vapor pressure. The holding time is not particularly limited, but 10 minutes or more and 30
Within a day is realistically appropriate. The holding temperature is not particularly limited, but 0 ° C or more and less than 50 ° C is practically appropriate. Here, it is naturally effective to hold at 50 ° C. or higher, and as described above, the heating operation at 50 ° C. or higher is defined as “baking”. Due to this retention in air, oxidation of glycidol-added polysilazane or hydrolysis by water vapor coexisting in air progresses, conversion to ceramics is completed, and it is toughened mainly by Si—O bond or Si—N bond. It becomes possible to form a coating film. According to the above method, various problems caused by the high firing temperature can be significantly reduced, and in some cases, conversion to ceramics near room temperature becomes possible.

[0073]

In the present invention, a rigid plate is arranged on the back surface to support the solar cell, and the film-coated surface is coated with an inorganic coating layer of a ceramic precursor to improve moisture permeation resistance, thereby reducing weight. It can be halved. Further, since only the inorganic coat layer may be cracked by heat stress, even if the inorganic coat layer is cracked by coating an elastic fluororesin-based organic coat layer on the inorganic coat layer. The moisture resistance can be maintained, and the cost can be reduced.

The ceramic precursor of the present invention is manufactured by Shokai 61.
-111162 differs from the sol-gel method used in Japanese Patent Laid-Open No. 111162 in basic properties in terms of film composition, denseness, and ceramization temperature. That is, in the sol-gel method, the film composition is composed of Si and O and does not contain N, whereas the ceramic precursor of the present invention is composed of Si, O and
In the evaluation of the sample in the case of baking at 350 ° C. for denseness {measurement of the entiglate by a 1% hydrofluoric acid solution (hydrofluoric acid: nitric acid = 1: 100)}, the sol-gel method (commercial sol-gel method) was used. Solution, OCD manufactured by Tokyo Ohka Co., Ltd.) is about 2000Å / min, while the ceramic precursor of the present invention is 500-800Å / min.
Since it shows min and is more dense, it can be seen that a reliable solar cell can be provided by coating with the ceramic precursor of the present invention. Further, as described above, the firing temperature of the sol-gel ceramic is 3
Since the temperature is from 00 to 350 ° C. or higher, it is essentially difficult to apply to a solar cell that needs to be sealed with a resin because the resin melts and decomposes.

[0075]

1 is a sectional view showing the structure of a solar cell of the present invention, and FIG. 2 is a plan view thereof. In the figure, 1 is a solar cell, 2 is a sealant, 10 is a back plate, 11 is a transparent film, 12 is an inorganic coating layer, 13 is an organic coating layer, 1
Reference numeral 4 is a frame, and 15 is an end face sealing material.

The back plate 10 is made of an aluminum plate having a thickness of 2 to 3 mm, a glass epoxy plate, a slate plate, a carbon fiber or the like, and a sealing agent 2 made of EVA (ethylene vinyl acetate) is filled on the back plate 10 to make a solar cell. Place 1 The solar cells 1 are electrically connected to each other by wiring (not shown). On top of this, a transparent surface film 11 such as PET is coated, and further, the inorganic coating layer 1 made of the ceramic precursor as described above.
2 and then a fluororesin-based organic coating layer 13 is coated. Further, the end portion is sealed with an end face sealing material 15 and fixed by the frame 14.

By coating the inorganic coating layer 12 on the transparent film 11 as described above, the moisture permeation resistance can be improved. Further, since the inorganic coating layer 12 alone may cause cracks due to thermal stress, by coating the organic coating layer 13 having further elasticity, moisture resistance can be maintained even if cracks occur. .

With such a structure, for example, the weight of the panel, which was about 7 kg in the past, can be reduced to about half, and the tempered glass used in the past was very expensive. Instead of this, an inexpensive material can be used, so that the cost can be reduced.

In the above embodiment, the organic coat layer is coated on the inorganic coat layer.
It is needless to say that the present invention is not limited to this, and the inorganic coat layer alone may be used, and even with this configuration, it sufficiently functions and is applicable.

[0080]

As described above, according to the present invention, a back plate made of a rigid body is used to support the whole, a surface of the solar cell is covered with a film, and an inorganic coating layer of a ceramic precursor or further Since the organic coating layer is coated on the top, it is possible to significantly reduce the weight compared to the conventional one that uses tempered glass, and to maintain moisture resistance and reduce costs. Is possible.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of a solar cell of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a diagram showing a structure of a conventional solar cell.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Solar cell, 2 ... Sealant, 10 ... Back plate, 11 ... Transparent film, 12 ... Inorganic coat layer, 13 ...
Organic coat layer, 14 ... Frame, 15 ... End face sealing material.

Claims (4)

[Claims] 1. A solar cell in which a plurality of solar cell modules are arranged by filling a sealing plate with a sealant on a rigid plate, and the surfaces of the solar cell modules are covered with a film, and an inorganic coating layer of a ceramic precursor is formed on the film. A solar cell characterized by being coated. 2. The solar cell according to claim 1, further comprising an organic coating layer coated on the inorganic coating layer. 3. The solar cell according to claim 1 or 2, wherein the ceramic precursor is represented by the general formula (1): Having a repeating unit of 100 to 50,
000 cyclic inorganic polysilazanes, chain inorganic polysilazanes, or a mixture thereof. 4. The solar cell according to claim 1, wherein the ceramic precursor is mainly represented by the general formula (2): (However, R ¹ , R ² and R ³ are each independently a hydrogen atom,
An alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, or a group other than these groups in which the group directly bonded to silicon is carbon, an alkylsilyl group, an alkylamino group, an alkoxy group, R ¹ , R ² and R ^At least one of which is a hydrogen atom), which has a main skeleton composed of a unit represented by a unit represented by the following formula: polysilazane having a number average molecular weight of 100 to 50,000 and glycidol, and having a glycidol / polysilazane weight ratio of 0. A solar cell comprising a coating composition containing at least a glycidol-added polysilazane having a number average molecular weight in the range of 001 to 2 and a number average molecular weight of about 200 to 500,000.