JP2001077390A - Solar battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize the degradation of solar battery performance under long-term outdoor exposure, particularly under high-temperature, high-humidity environments, by composing the solar battery of an ethylene-unsaturated fatty acid ester-unsaturated fatty acid ternary copolymer. SOLUTION: Photovoltaic elements 301 are laminated using a sealing material together with an ETFE film as a front film 303, which is prepared by corona- discharging a surface for bonding to a lower-layer closing material, a polyethylene terephthalate(PET) film as a backside film 304, and a galvalium steel sheet for roof material as a support plate 305. That is, an EMM sheet and the ETFE film are put over a light-receiving surface of the elements 301 and the EMM sheet, the PET film and the support plate are put over their backside, and they are heated at 150 deg.C for 30 minutes using a vacuum laminator while applying pressure and deaerating. Therefore, a solar battery module excellent in weather resistance, heat resistance, moisture resistance, and photoelectric conversion efficiency can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a solar cell module, and more particularly, to a solar cell module in which a light receiving surface and / or a non-light receiving surface of a photovoltaic element is sealed with an organic polymer resin.

[0002]

2. Description of the Related Art In recent years, awareness of environmental problems has been increasing worldwide. Above all, the danger of global warming caused by CO ₂ emission is serious, and the demand for clean energy is increasing more and more. At present, solar cells are promising as a clean energy source because of their safety and ease of handling.

FIG. 5 is a schematic sectional view showing a basic structure of a solar cell module. In FIG. 5, reference numeral 501 denotes a photovoltaic element, 502 denotes a sealing resin, 503 denotes a surface member,
04 is a back surface member. The sunlight passes through the surface member 503 and the sealing material resin 502, enters the light receiving surface of the photovoltaic element 501, and is converted into electric energy. The generated electricity is taken out from an output terminal (not shown).

[0004] The photovoltaic element cannot withstand outdoor use under severe environments. This is because the photovoltaic element itself is susceptible to corrosion and easily damaged by an external impact or the like. Therefore, it is necessary to cover and protect the photovoltaic element with a covering material. Most commonly, a photovoltaic element is placed between a transparent and weather-resistant surface member such as a glass or fluororesin film and a back surface member excellent in moisture-proof and electrical insulation such as an aluminum-laminated tedlar film or polyester film. And then laminating by sandwiching a sealing material resin.

As a conventional sealing resin for a solar cell, polyvinyl butyral and ethylene-vinyl acetate copolymer (EVA) have been mainly used. Among them, the crosslinkable composition of EVA has excellent properties in terms of heat resistance, weather resistance, transparency, cost, and the like, and is currently the mainstream sealing material for solar cells.

A solar cell module is required to have a high degree of durability because it is used outdoors for a long period of time. Although the durability of the photovoltaic element is, of course, excellent weather resistance and heat resistance are required for the coating material. However, in outdoor exposure for more than 10 years, yellowing of the encapsulant resin and peeling between members may become apparent due to light deterioration and heat deterioration of the coating material. The yellowing of the encapsulant resin causes a decrease in the amount of incident light and lowers the electrical output. In addition, peeling between members causes corrosion of the photovoltaic element or a metal member attached to the element due to intrusion of moisture into the peeled portion, leading to deterioration of solar cell performance.

EVA used conventionally is an excellent sealing material as described above, but is gradually deteriorated by hydrolysis or thermal decomposition. That is, EVA essentially has a property that acetic acid is easily desorbed, and acetic acid is desorbed by heat or moisture, and appears as yellowing, a decrease in mechanical strength, or a decrease in adhesive strength. Further, the generated acetic acid acts as a catalyst to further promote the deterioration. On the other hand, there is a problem that acetic acid corrodes various metal members such as a photovoltaic element and an electrode provided therewith.

In order to solve such a problem, a solar cell sealing material having higher durability than before has been proposed. Japanese Patent Application Laid-Open No. 7-302926 discloses that by using a copolymer resin of ethylene and an unsaturated fatty acid ester as a sealing material, heat resistance and moisture resistance are improved, and the performance of a photovoltaic element is degraded due to liberation of acid. Is disclosed. In particular, by using a copolymer resin of ethylene and an unsaturated fatty acid ester as a sealing material for a photovoltaic element in which a semiconductor thin film and a transparent conductive layer are formed on a conductive metal substrate, short-circuiting of the element due to acid can be prevented. It is described that a highly reliable solar cell module can be provided by preventing corrosion of a transparent conductive layer.

Japanese Patent Application Laid-Open No. 7-202236 discloses an ionomer resin, an ethylene-ethyl acrylate copolymer (EEA) resin, an ethylene-methacrylic acid random copolymer (EMAA) resin, an ethylene-
It is described that an acrylic acid copolymer (EAA) resin, an ethylene-methyl methacrylate copolymer (EMMA) resin, an ethylene-methyl acrylate copolymer (EMA) resin, and other adhesive polyolefin resins can be used.

[0010]

However, a copolymer resin of ethylene and an unsaturated fatty acid ester contains metal,
Adhesion with glass, other plastic materials, and the like was essentially low, and when used as a sealing material for a solar cell module, peeling off from elements, front surface members, back surface members, and the like was likely to occur. In order to improve this, conventionally, an adhesion improver is added to a sealing resin, an easy adhesion treatment, and the like are performed. Specifically, addition of a silane coupling agent or an organic titanate compound to a sealing resin is disclosed in Japanese Patent Publication No. 6-35575 or JP-A-9-36405, and when a film is used as a surface member, sealing is performed. Japanese Unexamined Patent Application Publication No. 9-90139 discloses that a surface treatment such as corona treatment, plasma treatment, ozone treatment, UV irradiation, electron beam irradiation, and flame treatment is performed on the bonding surface with the material resin.
36405.

However, the silane coupling agent and the organic titanate compound are susceptible to hydrolysis by water. During storage of the sheet, the silane coupling agent or the organic titanate compound reacts with moisture in the air and gradually loses its activity, so that the effect of improving the adhesiveness tends to be insufficient. In addition, the silane coupling agent or the organic titanate compound, which is responsible for maintaining the adhesiveness between the members even when the solar cell module is exposed to the outdoors, is gradually decomposed under the influence of light, heat, moisture, etc., and the adhesive strength is reduced. . On the other hand, surface treatments such as corona treatment and plasma treatment generate functional groups on the inactive film surface and mainly form hydrogen bonds with the sealing material resin to improve the adhesive strength. If the adhesiveness of the resin is essentially low, such as when there are few polar groups inside, a sufficient effect cannot be obtained.

On the other hand, a copolymer resin of ethylene and an unsaturated fatty acid improves the adhesiveness but has insufficient heat stability. Recently, as a solar cell module for electric power to be installed on the roof or wall of a house, a photovoltaic element integrated with a building material is directly attached to the building material. Although development is underway, such a module has a high module temperature of 80 ° C. or more due to poor ventilation on the back surface as compared with a conventional type mounted on a gantry. At such a high temperature, the copolymer resin with the unsaturated fatty acid gradually decomposes, causing yellowing and peeling.

In order to solve the above-mentioned drawbacks, the present invention has excellent weather resistance, heat resistance and light transmission, has poor water absorption, does not release acid even in the presence of moisture, and has good adhesion to various substrates. An object of the present invention is to provide an excellent solar cell module encapsulant resin and minimize deterioration of solar cell performance under long-term outdoor exposure, particularly in a high-temperature, high-humidity environment.

[0014]

Means for Solving the Problems As a result of intensive research and development for solving the above problems, the present inventor has found that the following method is the best.

That is, in a solar cell module in which the light-receiving surface and / or the non-light-receiving surface of the photovoltaic element is sealed with an organic polymer resin layer, at least one of the organic polymer resin layers is made of ethylene-free. Saturated fatty acid ester-
An unsaturated fatty acid terpolymer is used as a main component.

According to the present invention, the following effects can be expected.

A solar cell module having excellent weather resistance, heat resistance and moisture resistance can be provided. That is, since the essential adhesiveness of the sealing material is improved, peeling does not occur even in outdoor exposure for a long time. In addition, the encapsulant does not decompose in a high-temperature and high-humidity environment and acid is not released, which improves weather resistance and ensures stable solar cell performance over a long period of time because the photovoltaic element is not corroded by acid. Can be maintained.

The terpolymer is ethylene-acrylate-acrylic acid terpolymer, ethylene-acrylate-maleic anhydride terpolymer, ethylene-methacrylic acid ester-acrylic acid terpolymer. Copolymer, ethylene-acrylate-methacrylate terpolymer, ethylene-methacrylate-methacrylate terpolymer, ethylene-methacrylate-
Either a maleic anhydride terpolymer or a mixture of these makes it a sealing material that is well balanced in weather resistance, heat resistance, and moisture resistance, and has excellent light transmission. Thus, an extremely excellent solar cell module can be provided.

The content of each component of the terpolymer is such that the ethylene content is 65 to 89.9% by weight, the unsaturated fatty acid ester content is 10 to 30% by weight, and the unsaturated fatty acid content is 0. It is preferably from 0.1 to 5.0% by weight.
As a result, without impairing weather resistance, heat resistance, and moisture resistance,
Particularly excellent adhesiveness can be provided.

The terpolymer has a Vicat softening point of 40.
When the module is exposed to high temperatures during actual use, the encapsulant does not creep and deform, and when the Vicat softening point is 110 ° C or lower, conventional heating in the manufacturing process can be performed. A solar cell module can be easily manufactured by pressure bonding.

When the terpolymer contains a hindered amine light stabilizer, weather resistance is improved. That is, yellowing and decomposition of the sealing material during long-term outdoor exposure can be suppressed.

When the terpolymer contains an ultraviolet absorber, weather (light) resistance is improved. Further, deterioration of the member covered with the sealing material due to ultraviolet rays can be suppressed.

The ultraviolet absorber is selected from a benzophenone derivative and a benzotriazole derivative, so that the weather resistance of the sealing material can be improved while minimizing a decrease in the output of the solar cell. That is, there is no absorption in the visible light region necessary for power generation of the solar cell, and only ultraviolet light can be selectively absorbed.

When the terpolymer contains a silane coupling agent, the adhesion to inorganic materials is further improved.

When the terpolymer contains a hindered phenol antioxidant, heat resistance is improved.

Since the terpolymer has a total light transmittance at a thickness of 0.5 mm of 90% or more over the entire wavelength range of 400 to 1000 nm, the output of the solar cell is reduced due to optical loss of the sealing material. Can be minimized.

The acrylate is methyl acrylate, ethyl acrylate or (iso) butyl acrylate, and the methacrylate is methyl methacrylate, ethyl methacrylate or (iso) butyl methacrylate. Either way, resin can be manufactured at low cost, and module cost can be reduced.

The photovoltaic element has a semiconductor photoactive layer as a light conversion member and a transparent conductive layer as a second electrode formed on a conductive substrate as a first electrode. The effect of the sealing material of the invention can be enjoyed to the maximum.
In other words, there is no short circuit or corrosion of the element even during long-term outdoor exposure, and a highly reliable module can be obtained.

When the conductive substrate is made of stainless steel, the adhesive strength between the sealing resin and the substrate can be improved.

The photovoltaic element has a short-circuit portion repaired by a defect removing process, and has a shunt resistance of 1 kΩ · c.
When it is not less than m ^{2 and not} more than 500 kΩ · cm ² , the use of the sealing material of the present invention has a great effect. That is, the repaired short-circuit portion is not short-circuited again and the solar cell performance does not deteriorate.

A current collecting electrode containing copper or silver as one of the constituent elements is provided on the light receiving surface side surface of the photovoltaic element, and the terpolymer is disposed in contact with the current collecting electrode. By doing so, there is no possibility that the collector electrode is corroded by acid and the performance of the solar cell is degraded.

The light-receiving surface of the photovoltaic element is covered with the terpolymer and the outermost fluoride polymer thin film provided on the terpolymer to provide weather resistance, heat resistance and moisture resistance. An excellent lightweight and flexible solar cell module can be obtained. That is, although the moisture-proof property of the fluoride polymer thin film is low, the sealing material does not decompose due to moisture, so that a highly reliable module can be provided.

Since the photovoltaic element is bonded to the building material via the adhesive layer, the deterioration of the sealing material at high temperatures, which has conventionally been a problem in the building material integrated module, can be solved.

When the maximum use temperature is 80 ° C. or higher, the effect of improving the heat resistance of the sealing material of the present invention can be effectively enjoyed.

[0035]

FIG. 1 shows an example of a schematic configuration diagram of a solar cell module according to the present invention. In FIG. 1, 101 is a photovoltaic element, 102 is a surface sealing material, 103 is a front surface member, 104 is a back surface sealing material, and 105 is a back surface member.

The sealing members 102 and 104 in the present invention will be described in detail below.

The surface sealing material 102 is necessary for covering the unevenness of the photovoltaic element light receiving surface with a resin and protecting the element from the external environment. Also, it plays a role of bonding the surface member 103 to the element. Therefore, besides high transparency, weather resistance,
Adhesion and heat resistance are required. Furthermore, it must satisfy the low water absorption and the absence of acid release, which are the main objectives of the present invention. In order to satisfy these requirements, ethylene-acrylic acid ester-acrylic acid terpolymer, ethylene-acrylate ester-maleic anhydride terpolymer, ethylene-methacrylic ester-acrylic acid terpolymer are required. Coalesce, ethylene-acrylate-methacrylate terpolymer, ethylene-methacrylate-
It is suitable that any one of methacrylic acid terpolymer, ethylene-methacrylic acid ester-maleic anhydride terpolymer or a mixture thereof is used as a main component.

The acrylate and methacrylate include, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, (iso) propyl acrylate, (iso) propyl methacrylate, acrylic acid ( Iso) butyl, (iso) butyl methacrylate, hexyl acrylate, hexyl methacrylate, octyl acrylate, octyl methacrylate, lauryl acrylate, lauryl methacrylate, benzyl acrylate, benzyl methacrylate and the like. Of these, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, (iso) butyl acrylate, and (iso) butyl methacrylate are particularly preferred.

Specific examples of the terpolymer include ethylene-methyl acrylate-acrylic acid terpolymer, ethylene-methyl methacrylate-acrylic acid terpolymer, and ethylene-methyl acrylate-methacrylic acid. Terpolymer, ethylene-methyl methacrylate-methacrylic acid terpolymer, ethylene-ethyl acrylate-acrylic acid terpolymer, ethylene-ethyl methacrylate-acrylic acid terpolymer, ethylene- Ethyl acrylate-methacrylic acid terpolymer, ethylene-ethyl methacrylate-
Methacrylic acid terpolymer, ethylene-isobutyl acrylate-acrylic acid terpolymer, ethylene-isobutyl acrylate-methacrylic acid terpolymer, ethylene-
Isobutyl methacrylate-methacrylic acid terpolymer,
Ethylene-methyl acrylate-maleic anhydride terpolymer, ethylene-methyl methacrylate-maleic anhydride terpolymer, ethylene-ethyl acrylate-maleic anhydride terpolymer, ethylene-ethyl methacrylate −
Maleic anhydride terpolymer and the like are used as suitable materials.

Among these copolymers, from the viewpoint of availability and economy, preferred are ethylene-methyl acrylate-maleic anhydride terpolymer, ethylene-ethyl acrylate-maleic anhydride terpolymer. Terpolymer, ethylene-isobutyl acrylate-methacrylic acid terpolymer, and especially ethylene-methyl acrylate-maleic anhydride terpolymer and ethylene in terms of achieving both transparency and adhesiveness. Most preferred is isobutyl acrylate-methacrylic acid terpolymer.

Further, the terpolymer has an ethylene content of 65 to 89.9% by weight, an unsaturated fatty acid ester content of 10 to 30% by weight, and an unsaturated fatty acid content of 0.1 to 5%.
When the content is 0% by weight, the adhesion can be improved without impairing the weather resistance, heat resistance, and moisture resistance.

On the other hand, the terpolymer has a Vicat softening point of 4
When the temperature is 0 ° C. or higher, the sealing material does not creep and deform even when the module is exposed to a high temperature in actual use. It is preferable because a solar cell module can be manufactured at a low temperature.

The sealing resin may be crosslinked to improve heat resistance and adhesiveness. As a method for crosslinking the sealing material, generally, isocyanate, melamine, an organic peroxide, or the like is used.

The crosslinking agent used in the present invention is preferably one having a sufficiently long pot life and a rapid crosslinking reaction at the time of crosslinking. Since the surface member is laminated on the sealing material, the crosslinking agent is free from the crosslinking agent. It is preferable that there is no or a trace amount. Organic peroxides satisfy the above requirements. Hereinafter, the organic peroxide will be described in detail.

Crosslinking with an organic peroxide causes the free radicals generated from the organic peroxide to extract hydrogen from the resin and cause
This is done by forming a -C bond. Thermal decomposition, redox decomposition and ionic decomposition are known as methods for activating organic peroxides. Generally, the thermal decomposition method is preferred.

Organic peroxides are roughly classified into hydroperoxides, dialkyl (allyl) peroxides, diacyl peroxides, peroxyketals, peroxyesters, peroxycarbonates and ketone peroxides according to their chemical structures.

Examples of hydroperoxides include t-butyl peroxide, 1,1,3,3-tetramethylbutyl peroxide, p-menthane hydroperoxide, cumesihydroperoxide, p-cymene hydroperoxide, diisopropylbensen peroxide, 2,5 -Dimethylhexane 2,5-dihydroperoxide, cyclohexane peroxide, 3,3,5-trimethylhexanone peroxide and the like.

The dialkyl (allyl) peroxide includes di-t-butyl peroxide, dicumyl peroxide, t-butyl gramyl peroxide and the like.

The diacyl peroxides include diacetyl peroxide, dipropionyl peroxide, diisobutyryl peroxide, dioctanoyl peroxide,
Didecanoyl peroxide, dilauroyl peroxide, bis (3,3,5-trimethylhexanoyl) peroxide, benzoyl peroxide, m-toluyl peroxide, p-chlorobenzoyl peroxide, 2,4
-Dichlorobenzoyl peroxide, peroxysuccinic acid and the like.

The peroxyketals include 2,2-di-t-butylperoxybutane, 1,1-di-t-butylperoxycyclohexane, and 1,1-di- (t-butylperoxy) -3,3,5. -Trimethylcyclohexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-
Butylperoxy) hexyne-3,1,3-di (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-dibenzoylperoxyhexane, 2,
5-dimethyl-2,5-di (peroxybenzoyl) hexyne-3, n-butyl-4,4-bis (t-butylperoxy) valerate and the like.

Examples of peroxyesters include t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxypivalate, t-butyl peroxy neodecanoate, and t-butyl peroxy 3,3,5-trimethyl. Sanoate, t-butylperoxy 2-ethylhexanoate, (1,1,3,3-
Tetramethylbutylperoxy) 2-ethylhexanoate, t-butylperoxylaurate, t-butylperoxybenzoate, di (t-butylperoxy) adipate, 2,5-dimethyl2,5-di (peroxy2
-Ethylhexanoyl) hexane, di (t-butylperoxy) isophthalate, t-butylperoxymalate, acetylcyclohexylsulfonyl peroxide and the like.

The peroxycarbonates include t-butylperoxyisopropylcarbonate, di-n-propylperoxydicarbonate, di-sec-butylperoxydicarbonate, di (isopropylperoxy) dicarbonate and di (2-ethylhexylperoxycarbonate). ) Dicarbonate, di (2-ethoxyethylperoxy) dicarbonate, di (methoxyidopropylperoxy) carbonate, di (3-methoxybutylperoxy) dicarbonate, bis- (4-t-butylcyclohexylperoxy) dicarbonate and the like.

Examples of ketone peroxides include acetylacetone peroxide, methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, ketone peroxide and the like. As other structures, vinyl tris (t-butylperoxy) silane and the like are also known.

The amount of the organic peroxide to be added is preferably 0.1 to 5 parts by weight based on 100 parts by weight of the resin.

It is possible to mix the above-mentioned organic peroxide into a sealing material and carry out crosslinking and thermocompression bonding of the solar cell module while heating under pressure. The heating temperature and time can be determined by the thermal decomposition temperature characteristics of each organic peroxide. Preferably 90% pyrolysis, more preferably 95%
The heating is completed when the temperature and the time have passed. As a pressing method, there are a method of pressing with a hot roll and a hot press, and a method of pressing at atmospheric pressure by reducing the pressure in the system using an air bag-shaped jig. In order to carry out the above-mentioned crosslinking reaction efficiently, it is desirable to use triallyl cyanurate, which is called a crosslinking assistant. Preferably resin 100
0.1 to 5 parts by weight of a crosslinking aid is added to parts by weight.

When maleic anhydride is contained in the terpolymer, a polyhydric alcohol can be added as a crosslinking agent. That is, the hydroxyl group of the polyhydric alcohol reacts with the maleic anhydride to form a crosslinked structure. Specific examples of such polyhydric alcohols include ethylene glycol, glycerin, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, trimethylolmethane, and trimethylolmethane. Alcohol compounds such as methylolethane, trimethylolpropane, and pentaerythritol;
Polyethylene glycol such as diethylene glycol, triethylene glycol and tetraethylene glycol; polyglycerin such as diglycerin, triglycerin and tetraglycerin; albitol, sorbitol, xylose, arabinose, glucose, galactose, sorbose, fructose, palatinose, malt Sugars such as triose, malegitose, sorbitan, etc .; dehydration condensates of these saccharides; polyoxyalkylene compounds obtained by adding ethylene oxide or propylene oxide to the above various compounds; partial esterification of the above various compounds with carboxylic acids A compound obtained by partially esterifying the above-mentioned polyoxyalkenylene compound with a carboxylic acid; and further adding ethylene oxide or Polyoxyalkylene compound to which propylene oxide is added; saponified ethylene-vinyl acetate copolymer, polyvinyl alcohol, polyolefin oligomer having two or more hydroxyl groups, ethylene-hydroxyethyl acrylate copolymer, ethylene-hydroxyethyl methacrylate copolymer Polymers having two or more hydroxyl groups, such as a coalescence, may be mentioned. Two or more of these polyhydric alcohol compounds may be used simultaneously.

The amount of the polyhydric alcohol to be added is preferably such that the molar ratio of the hydroxyl group contained in the polyhydric alcohol to the acid anhydride in the terpolymer is in the range of 0.05 to 5. .

In order to promote the reaction between the hydroxyl group and the acid anhydride and efficiently carry out the crosslinking reaction, it is desirable to use a reaction accelerator. Specific examples include metal salts of organic carboxylic acids. Preferably, 0.01 to 15 parts by weight of an organic carboxylic acid metal salt is added to 100 parts by weight of the resin.

It is often the case that a thermal oxidation inhibitor is added to the sealing material resin in order to impart stability at high temperatures. The addition amount is 0.1 to 1 with respect to 100 parts by weight of the resin.
Parts by weight are preferred.

The chemical structure of the antioxidant is roughly classified into monophenol type, bisphenol type, polymer type phenol type, sulfur type and phosphoric acid type.

In the case of monophenol, 2,6-di-ter
There are t-butyl-p-cresol, butylated hydroxyanisole, and 2,6-di-tert-butyl-4-ethylphenol.

For bisphenols, 2,2'-methylene-bis- (4-methyl-6-tert-butylphenol) and 2,2'-methylene-bis- (4-ethyl-6-
tert-butylphenol), 4,4′-thio-bis- (3-methyl-6-tert-butylphenol),
4,4'-butylidene-bis- (3-methyl-6-te
rt-butylphenol), 3,9-bis [{1,1-
Dimethyl-2- {β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy}
Ethyl @ 2,4,8,10-tetraoxaspiro] 5
5-undecane.

As the polymer phenols, 1,1,3-
Tris- (2-methyl-4-hydroxy-5-tert
-Butylphenyl) butane, 1,3,5-trimethyl-
2,4,6-tris (3,5-di-tert-butyl-
4-Hydroxybenzyl) benzene, tetrakis-dimethylene-3- (3 ', 5'-di-tert-butyl-
4'-hydroxyphenyl) propionate @ methane,
Bis-｛(3,3'-bis-4'-hydroxy-3'-
tert-butylphenyl) butyric acid glycol ester, 1,3,5-tris (3 ′, 5′-di-tert-butyl-4′-hydroxybenzyl) -s
-Triazine-2,4,6- (1H, 3H, 5H) trione and tocopherol (vitamin E) are known.

On the other hand, sulfur-based compounds include dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiopropionate.

In the phosphoric acid system, triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, 4,4′-butylidene-bis- (3-
Methyl-6-tert-butylphenyl-di-tridecyl) phosphite, cyclic neopentanetetraylbis (octadecylphosphite), tris (mono and / or diphenyl) phosphite, diisodecylpentaerythritol diphosphite, 9,10 −
Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10- (3,5-di-tert-
(Butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10
-Oxide, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene, cyclic neopentanetetraylbis (2,4-di-te
rt-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,6-di-tert-methylphenyl) phosphite, and 2,2-methylenebis (4,6-tert-butylphenyl) octyl phosphite. .

Further, it is desirable to add an ultraviolet absorber to suppress the light deterioration of the sealing material resin and improve the weather resistance, or to protect the lower layer of the sealing material resin. The addition amount is about 0.1 to 0.5 parts by weight based on 100 parts by weight of the resin. Known compounds are used as the ultraviolet absorber. The chemical structure is roughly classified into salicylic acid, benzophenone, benzotriazole, and cyanoacrylate.

Examples of salicylic acids include phenyl salicylate, p-tert-butylphenyl salicylate, p-
There is octylphenyl salicylate.

In the benzophenone system, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2'-dihydroxy-4 -Methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-
5-sulfobenzophenone, bis (2-methoxy-4-
(Hydroxy-5-benzophenone) methane.

As benzotriazoles, 2- (2-
(Hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-butylphenyl) benzotriazole, 2- (2-hydroxy-
3,5-di-tert-butylphenyl) benzotriazole, 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3,5- Di-tert-butylphenyl) -5-chlorobenzotriazole, 2-
(2-hydroxy-3,5-di-tert-amylylphenyl) benzotriazole, 2- {2-hydroxy-
3- (3,4,5,6-tetrahydrophthalimidomethyl) -5-methylphenyl} benzotriazole, 2,
2-methylenebis {4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol}.

Examples of the cyanoacrylate include 2-ethylhexyl-2-cyano-3,3'-diphenylacrylate and ethyl-2-cyano-3,3'-diphenylacrylate.

Among these ultraviolet absorbers, benzophenone-based and benzotriazole-based materials are preferred as solar cell sealing materials from the viewpoint that they have little absorption in the visible light region of 400 nm or more and have high heat stability. .

It is known that a hindered amine-based light stabilizer can be used as a method for imparting weather resistance other than the above-mentioned ultraviolet absorber. A hindered amine-based light stabilizer does not absorb ultraviolet rays unlike an ultraviolet absorber, but exhibits a remarkable synergistic effect when used in combination with an ultraviolet absorber. The addition amount is 0.1 to 0.3 with respect to 100 parts by weight of the resin.
It is generally about parts by weight. Of course, some other materials than hindered amines can function as light stabilizers, but are often colored, which is not desirable for the encapsulant of the present invention. However, in the case where the module itself is colored, a colored light stabilizer may be used.

As the hindered amine light stabilizer, dimethyl-1- (2-hydroxyethyl) -4-succinate is used.
Hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-
Diyl {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene} (2,2,6,6-
Tetramethyl-4-piperidyl) imino {], N, N '
-Bis (3-aminopropyl) ethylenediamine.2
4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-
1,3,5-triazine condensate, bis (2,2,6,6
-Tetramethyl-4-piperidyl) sebalate, 2-
(3,5-di-tert-4-hydroxybenzyl)-
Bis (1,2,2,6,6-pentamethyl-4-piperidyl) 2-n-butylmalonate and the like are known.

It is preferable to use a low-volatility ultraviolet absorber, light stabilizer and thermal antioxidant in consideration of the usage environment of the solar cell module.

When it is assumed that the solar cell module is used in a more severe environment, it is preferable to improve the adhesive strength between the sealing material and the photovoltaic element or surface member. The adhesive strength can be improved by adding a silane coupling agent or an organic titanate compound to the sealing material.
Specific examples of the silane coupling agent include vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ) Ethyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ
-Aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane and the like.

On the other hand, in order to minimize the decrease in the amount of light reaching the photovoltaic element, the sealing resin (surface sealing material) 1
02 is preferably 80% or more, more preferably 90% or more in the visible light wavelength region of 400 nm or more and 800 nm or less. Further, in order to facilitate the incidence of light from the atmosphere, the refractive index is preferably from 1.1 to 2.0, and more preferably from 1.1 to 1.6.

The back surface sealing material 104 is provided to cover the irregularities on the back surface of the photovoltaic element with a resin and to protect the element from an external environment. Further, it also plays a role of bonding the back surface member 105 to the element. Therefore, since weather resistance, adhesiveness, and heat resistance are required similarly to the surface sealing material, it is preferable to use a material suitable as the surface sealing material also as the back surface sealing material. Usually, the same material as the front surface sealing material is used for the back surface sealing material. However, since transparency is not essential, a filler such as an inorganic oxide may be added to improve weather resistance and mechanical strength, or may be colored with a pigment.

The photovoltaic element 101 according to the present invention includes a crystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell, a microcrystalline silicon solar cell, a thin film crystalline silicon solar cell, a copper indium selenide solar cell, Conventionally known devices such as compound semiconductor solar cells may be selected and used in accordance with the purpose, but the terpolymer of the present invention can be suitably encapsulated by, for example, applying a light- A semiconductor photoactive layer as a conversion member and a transparent conductive layer are formed. FIG. 2 shows a schematic configuration diagram as an example. FIG. 2A is a schematic cross-sectional view of the photovoltaic element, and FIG. 2B is a schematic top view of the photovoltaic element. In these figures, 201 is a conductive substrate, 2
02 is a back reflection layer, 203 is a semiconductor photoactive layer, 204 is a transparent conductive layer, 205 is a collecting electrode, 206a and 206b are output terminals, 207 and 208 are conductive adhesives or conductive solder or metal wax such as solder. It is.

The conductive base 201 serves as a base for the photovoltaic element and also serves as a lower electrode. Materials include silicon, tantalum, molybdenum, tungsten,
Examples include stainless steel, aluminum, copper, titanium, carbon sheets, lead-plated steel sheets, resin films having a conductive layer formed thereon, and ceramics. Among them, stainless steel is preferable because of its high durability and excellent adhesion to the terpolymer of the present invention.

On the conductive substrate 201, the back reflection layer 2
As 02, a metal layer, a metal oxide layer, or a metal layer and a metal oxide layer may be formed. In the metal layer,
For example, Ti, Cr, Mo, W, Al, Ag, Ni, and the like are used, and ZnO, T
iO ₂ , SnO ₂ or the like is used. Examples of a method for forming the metal layer and the metal oxide layer include a resistance heating evaporation method, an electron beam evaporation method, and a sputtering method.

The semiconductor photoactive layer 203 is a part for performing photoelectric conversion.
For example, a specific material is a pn junction type polycrystalline silicon.
, Pin junction type amorphous silicon, pin junction type
Microcrystalline silicon or CuInSe_Two, CuIn
S_Two, GaAs, CdS / Cu _TwoS, CdS / CdT
e, CdS / InP, CdTe / Cu_TwoTe and others
And the like. Above all, pin connection
Integrated amorphous silicon, pin junction type microcrystalline silicon
Is preferable because the cost of raw materials is low and the process is relatively simple.
You.

The method for forming the semiconductor photoactive layer is as follows.
In the case of polycrystalline silicon, a sheet of molten silicon or heat treatment of amorphous silicon is used. In the case of amorphous silicon and microcrystalline silicon, plasma C using silane gas as a raw material is used.
In the case of VD or compound semiconductor, there are ion plating, ion beam deposition, vacuum evaporation, sputtering, and electrodeposition.

The transparent conductive layer 204 functions as an upper electrode of a solar cell. As a material to be used, for example, I
_{n 2 O 3, SnO 2,} In 2 O 3 -SnO 2 (ITO), Zn
There are O, TiO ₂ , Cd ₂ SnO ₄ , and a crystalline semiconductor layer doped with a high concentration of impurities. Examples of the formation method include resistance heating evaporation, sputtering, spraying, CVD, and impurity diffusion.

Incidentally, in the photovoltaic element formed up to the transparent conductive layer 204, the conductive base and the transparent conductive layer are partially formed due to the non-smoothness of the conductive base 201 and / or the non-uniformity in forming the semiconductor photoactive layer. In this case, a large leakage current flows in proportion to the output voltage, that is, the leakage resistance (shunt resistance) is small. Therefore, it is desirable to perform a defect removal process after forming the transparent conductive layer in order to repair this. USP Patent Publication 47
No. 29970 describes details of such defect removal. This method shunt resistance of the photovoltaic element 1 k [Omega · cm ² or more 500 k [Omega] · cm ² or less, preferably 10 k.OMEGA · cm ² or more 500 k [Omega] · cm ²
The following is assumed.

On the transparent conductive layer 204, a grid-like, comb-like, line-like, etc. collecting electrode 205 (grid) may be provided in order to efficiently collect current. Current collecting electrode 205
For example, Ti, Cr, Mo,
Conductive pastes such as W, Al, Ag, Ni, Cu, Sn, and silver paste are exemplified. As a method for forming the current collecting electrode 205, sputtering using a mask pattern, resistance heating, a CVD method, a method in which an unnecessary portion is removed by etching after depositing a metal film on the entire surface and patterning is performed, or a grid directly formed by photo CVD. A method of forming an electrode pattern, a method of plating after forming a mask of a negative pattern of a grid electrode pattern,
There are a method of printing a conductive paste and a method of fixing a metal wire to the printed conductive paste with solder. As the conductive paste, one obtained by dispersing silver, gold, copper, nickel, carbon or the like in a fine powder form in a binder polymer is usually used. As a binder polymer,
For example, resins such as polyester, epoxy, acrylic, alkyd, polyvinyl acetate, rubber, urethane, and phenol can be used.

Finally, the output terminal 2 is used to extract the electromotive force.
06 is attached to the conductive substrate 201 and the current collecting electrode 205. A method in which a metal body such as a copper tab is joined to the conductive base by spot welding or soldering, and a method in which the metal body is electrically connected to the current collecting electrode by conductive paste or solder 207, 208 is used. Can be

The photovoltaic elements produced by the above method are connected in series or in parallel according to a desired voltage or current. Further, a desired voltage or current can be obtained by integrating a photovoltaic element on an insulated substrate.

In FIG. 1, since the surface member 103 is located on the outermost layer of the solar cell module, it has properties such as weather resistance, contamination resistance, and mechanical strength, as well as long-term reliability in outdoor exposure of the solar cell module. is necessary. The members suitably used in the present invention include a (reinforced) glass plate and a fluoride polymer film. It is preferable to use a white plate glass having a high light transmittance as the glass plate. Specific examples of the fluoride polymer film include ethylene tetrafluoride-ethylene copolymer (ETFE), polyvinyl fluoride resin (PVF), polyvinylidene fluoride resin (PVDF), polytetrafluoroethylene resin (TFE),
Ethylene tetrafluoride-propylene hexafluoride copolymer (FE
P) and poly (chlorotrifluoroethylene) resin (CTFE). Polyvinylidene fluoride resin is excellent in terms of weather resistance, but ethylene tetrafluoride-ethylene copolymer is excellent in terms of both weather resistance and mechanical strength. In order to improve the adhesiveness between the fluoride polymer film and the sealing material, it is desirable to perform corona treatment and plasma treatment on the film. It is also possible to use a film that has been subjected to a stretching treatment for improving the mechanical strength.

The back surface member 105 has a role of maintaining electrical insulation between the photovoltaic element 101 and the outside, a role of a reinforcing material, a role of enhancing weather resistance, and the like, as necessary. As the material, a material which can secure sufficient electric insulation, has excellent long-term durability, can withstand thermal expansion and thermal contraction, and has flexibility is preferable. As a suitably used member,
Nylon film, polyethylene terephthalate (PE
T) Films and polyvinyl fluoride films. When moisture resistance is required, aluminum laminated polyvinyl fluoride film, aluminum evaporated PET film,
A silicon oxide-deposited PET film or the like is used. further,
In order to improve the fire resistance of the module, a galvanized iron foil, a stainless steel foil or the like laminated with a film may be used as the back surface member. A support plate may be attached to the outside of the back member in order to increase the mechanical strength of the solar cell module or to prevent distortion and warpage due to a temperature change. For example, steel plate, plastic plate,
FRP (glass fiber reinforced plastic) plates are preferred.
In addition, a building material-integrated solar cell module can be obtained by attaching a building material. As the building material, various types can be selected from a metal plate, a slate board, a gypsum board, a tile, a glass fiber reinforced plastic, glass, and the like. Among them, a weather-resistant metal plate such as a galvanized steel plate, a galvalume steel plate, a stainless steel plate, and an aluminum plate is lightweight and easy to process, and thus is suitably used for a building material (roof material) integrated solar cell module.

A method for forming a solar cell module using the above-described photovoltaic element, sealing resin, front surface member, and rear surface member will be described below.

In order to cover the photovoltaic element with the sealing resin, the sealing material melted by heating is extruded from a slit of a T-die or the like to form a sheet of the sealing material, and this is heated and pressed on the element. Is common. The sealing material sheet is inserted between the element and the front surface member and between the element and the back surface member, and is heated and pressed to obtain a solar cell module.

As the method of thermocompression bonding, conventionally known vacuum lamination, roll lamination and the like can be variously selected and used.

[0093]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a solar cell module according to the present invention will be described in detail based on embodiments. It should be noted that the solar cell module according to the present invention is not limited to the following embodiments at all, and can be variously modified within the scope of the gist.

(Example 1) [Photovoltaic element] First, amorphous silicon (a-S
i) A solar cell (photovoltaic element) was manufactured. The manufacturing procedure will be described with reference to FIG.

On a cleaned stainless steel substrate 201, an Al layer (film thickness: 5000) was formed as a back reflection layer 202 by a sputtering method.
Å) and a ZnO layer (thickness 5,000 膜厚) were formed sequentially. Then, SiH ₄ , PH _3, and H ₂ were formed by plasma CVD.
An i-type a-Si layer from a mixed gas of SiH ₄ and H ₂ , a p-type microcrystalline μc-Si layer from a mixed gas of SiH ₄ , BF ₃ and H _2. Formed, and the thickness of the n-layer is 150Å / i-layer thickness of 4000Å / p-layer thickness of 100Å / n
Layer thickness 100 ° / i-layer thickness 800 ° / p-layer thickness 100 °
Tandem a-Si photoelectric conversion semiconductor layer 203 having a layer structure of
Was formed. Next, as the transparent conductive layer 204, In ₂ O
A thin film (thickness: 700 °) was formed by depositing In by a resistance heating method in an O ₂ atmosphere.

Thereafter, a process of removing defects of the photovoltaic element was performed. That is, the photovoltaic element and the electrode plate are immersed in an aqueous solution of aluminum chloride prepared so that the electric conductivity is 50 to 70 mS so as to face the transparent conductive layer of the element, and the element is grounded to the electrode plate. The transparent conductive layer in the shunted portion was selectively decomposed by applying a positive potential of 3.5 volts for 2 seconds. By this treatment, the shunt resistance of the photovoltaic element becomes 1 kΩ · cm ^{2 to} 10 kΩ before treatment.
Whereas was kΩ · cm ^2, after processing 50kΩ · cm ²
To 200 kΩ · cm ² .

Further, a grid electrode 205 for current collection is formed by screen printing of silver paste. Finally, a copper tab is attached to a stainless steel substrate as a minus side terminal 206b using a stainless solder 208, and a plus side terminal 20b is formed.
For 6a, a tin foil tape was attached to the current collecting electrode 205 with a conductive adhesive 207 to serve as an output terminal, and a photovoltaic element was obtained. A plurality of the photovoltaic elements were connected in series to form a photovoltaic element group.

Finally, the plus side electrode of the plus end element and the minus side electrode of the minus end element were extended and disposed on the back surface of the photovoltaic element group to obtain an output output electrode.

Next, a method for manufacturing a solar cell module will be described with reference to FIG.

[Sealant] As the sealant 302, ethylene-methyl acrylate-maleic anhydride terpolymer (EMM) resin pellets (methyl acrylate content 20
wt%, maleic anhydride content 3 wt%, Vicat softening point 55 ° C.)
-Dimethyl-2,5-bis (t-butylperoxy) hexane 3 parts by weight, γ-methacryloxypropyltrimethoxysilane 0.3 part by weight as a silane coupling agent, 2-hydroxy-4-n as an ultraviolet absorber 0.3 parts by weight of octoxybenzophenone, 0.1 parts by weight of bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate as a light stabilizer, and tris (mono-nonylphenyl) as an antioxidant A 400-μm-thick sheet-shaped EMM (hereinafter referred to as an EMM sheet) formed by heating and melting each of which 0.2 parts by weight of phosphite was added and extruding through a slit of a T-die was used.

The front film 303 is an ETFE film (50 μm thick) whose surface to be adhered to the lower sealing material is subjected to corona discharge treatment, and the back film 304 is a polyethylene terephthalate (PET) film (100 μm thick).
m), a galvalume steel plate (0.4 mm thick) for roof material was used as the support plate 305.

[Lamination] The photovoltaic element group 301 was laminated with the configuration shown in FIG. That is, the EMM sheet and the ETFE film are stacked on the light receiving surface side of the photovoltaic element, and the EMM sheet, the PET film and the support plate are stacked on the back side, and heated at 150 ° C. for 30 minutes while degassing under pressure using a vacuum laminating apparatus. did. The output terminal was turned on the back surface of the element, and after lamination, the output could be taken out from the terminal take-out opening previously opened in the galvalume steel plate.

Through the above steps, a plurality of solar cell modules embodying the present invention were obtained.

(Example 2) In Example 1, ethylene-
Methyl acrylate-maleic anhydride terpolymer (EM
M) Instead of resin, ethylene-isobutyl acrylate-
A solar cell module was produced in exactly the same manner except that a methacrylic acid terpolymer (EiBAMMA) resin (isobutyl acrylate content 20 wt%, methacrylic acid content 8 wt%, Vicat softening point 40 ° C.) was used. .

Example 3 Example 1 was repeated except that EMM resin pellets having a methyl acrylate content of 25 wt%, maleic anhydride 1.5 wt%, and a Vicat softening point of 40 ° C. were used as the EMM resin. Produced a solar cell module in exactly the same manner.

(Embodiment 4) In Embodiment 2, EiBA
As MMA resin, isobutyl acrylate content 15w
A solar cell module was obtained in exactly the same manner except that an EiBAMMA resin pellet having a t%, a methacrylic acid content of 4 wt%, and a Vicat softening point of 60 ° C. was used.

(Example 5) In Example 1, an EMM sheet was prepared without adding a crosslinking agent. Since cross-linking was unnecessary, the heating time was reduced to 10 minutes and vacuum lamination was performed. Other than that is the same.

Example 6 A photovoltaic element group was manufactured in the same manner as in Example 1.

[Modularization] A method of covering a group of photovoltaic elements into a solar cell module will be described with reference to FIG. Reference numeral 401 denotes a photovoltaic element group, 402 denotes a sealing resin,
03 is a cover glass, and 404 is a back film. Photovoltaic element group 401, EMM sheet 402 (thickness 400 μm), white plate reinforced glass 403 (thickness 3.3 mm) prepared in Example 1, polyethylene terephthalate (PET) film 404 (thickness) having an adhesive surface subjected to corona discharge treatment Sa1
00 μm) of glass / EMM sheet / photovoltaic element group /
The EMM sheet / PET film was stacked in this order to form a solar cell module laminate. The laminate was heat-pressed at 150 ° C. for 30 minutes while degassing under pressure using a vacuum laminator to obtain a solar cell module.

The output terminal was previously turned around the back surface of the photovoltaic element, and after lamination, holes were made in the back surface sealing material and the back surface film so that the output could be taken out.

(Comparative Example 1) In Example 1, an EVA resin (vinyl acetate content: 33 wt%,
A solar cell module was obtained in exactly the same manner except that a Vicat softening point of less than 40 ° C.) was used.

Comparative Example 2 In Example 1, an EVA resin having a vinyl acetate content of 28 wt% and a Vicat softening point of 42 ° C. was used in place of the EMM resin. Other than that is the same.

Comparative Example 3 In Example 1, an EEA resin (ethyl acrylate content 25 w
t%, Vicat softening point 40 ° C). Other than that is the same.

(Comparative Example 4) In Example 1, EMA resin (methyl acrylate content 20 w
t%, Vicat softening point 43 ° C.). Other than that is the same.

Comparative Example 5 An EMAA resin (methacrylic acid content 15 w
t%, Vicat softening point 64 ° C). Other than that is the same.

(Comparative Example 6) In Example 6, an EVA resin (vinyl acetate content: 33 wt%,
A solar cell module was obtained in exactly the same manner except that a Vicat softening point of less than 40 ° C.) was used.

(Evaluation Method) The following items were evaluated for the solar cell modules manufactured in the above Examples and Comparative Examples.

(1) Weather Resistance A solar cell module was put into a sunshine weatherometer (manufactured by Suga Test Instruments Co., Ltd.) and irradiated with light from a xenon lamp (irradiation intensity: 3 SUN, atmosphere: black panel temperature 83 ° C./humidity 50% RH). ), An accelerated weathering test was conducted in which rainfall was repeated every 2 hours for 8 minutes, and changes in appearance after 5000 hours were observed. Observation results are shown in Table 1 as ○ when there was no change, and the situation was simply commented in Table 1 when there was a change.

(2) Moisture resistance A light receiving surface of 100 mW / cm ² was measured using a solar simulator.
The solar cell module was placed in an atmosphere of 85 ° C./85% RH for 1000 hours while irradiating the pseudo sunlight of the above, and the AM of the solar cell module before and after the test was 1.5 and 100 mW / c.
The conversion efficiency under light irradiation of m ² was measured, and the relative reduction rate of the conversion efficiency on the average of 10 modules was determined. The module used here is one in which the conversion efficiency has been sufficiently stabilized by irradiating light before the test. In addition, the shunt resistance in the dark state before and after the test was also measured, and the relative reduction rate of the average shunt resistance of 10 modules was determined. Further, changes in appearance after the test were observed. Observation results are shown in Table 1 as ○ when there was no change, and the situation was simply commented in Table 1 when there was a change.

(3) Temperature / Humidity Cycle A temperature / humidity cycle test of −40 ° C./30 minutes and 85 ° C./85% RH / 20 hours was performed 10 times, and changes in the appearance of the solar cell module after the test were observed. Observation results
Those with no change are shown in Table 1 as ○, and those with change were briefly commented on the situation to wife 1.

(4) Heat Resistance The solar cell module was left in an atmosphere at 95 ° C. for 1000 hours, and changes in the external appearance were observed. Observation results are shown in Table 1 as ○ when there was no change, and the situation was simply commented in Table 1 when there was a change.

Table 1 shows the results.

[0123]

[Table 1]

As is clear from Table 1, the solar cell module sealed with the resin of the present invention has excellent durability in all of weather resistance, moisture resistance and heat resistance. In Example 5, slight deformation of the sealing material was observed because the sealing material was not cross-linked, but this was not a problem in practical use.

In Comparative Examples 1 and 2, peeling or yellowing occurred, which was presumed to be due to the decomposition of the sealing resin, and copper as one of the electrode members was corroded by the acid generated by the decomposition. Have been. In addition, a large decrease in shunt resistance, which is considered to be caused by the generation of acid and the absorption of resin, is observed, and the conversion efficiency is significantly reduced.

On the other hand, in Comparative Examples 3 and 4, peeling occurred, which was presumed to be due to the intrinsic low adhesiveness of the sealing resin.

In Comparative Example 6, yellowing of the sealing material occurred in the weather resistance test. Since the module of Comparative Example 6 was covered with glass, it is presumed that the acid generated by the decomposition was accumulated in the sealing material, and the deterioration of the sealing material resin was promoted by using the acid as a catalyst.

The solar cell module according to the present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the invention.

[0129]

According to the present invention, in a solar cell module in which a light receiving surface and / or a non-light receiving surface of a photovoltaic element is sealed with an organic polymer resin layer, at least one of the organic polymer resin layers When one layer contains a specific ethylene-unsaturated fatty acid ester-unsaturated fatty acid terpolymer, a solar cell module excellent in weather resistance, heat resistance, moisture resistance and photoelectric conversion efficiency can be provided. That is, since the sealing material has high light-transmitting property, peeling of the sealing material from other members does not easily occur, and corrosion of the photovoltaic element and reduction in shunt resistance can be suppressed, so that the solar cell can be stable for a long time. Battery performance can be maintained.

[Brief description of the drawings]

FIG. 1 is an example of a schematic sectional view of a solar cell module embodying the present invention.

2 is an example of a schematic cross-sectional view ((a)) and a top view ((b)) of a light-receiving surface showing a basic configuration of a photovoltaic element used in the solar cell module of FIG.

FIG. 3 is a schematic sectional view of a solar cell module of Example 1.

FIG. 4 is a schematic sectional view of a solar cell module of Example 6.

FIG. 5 is a schematic sectional view showing an example of a conventional solar cell module.

[Explanation of symbols]

101, 201, 301, 401, 501 Photovoltaic element 102 Surface sealant 103, 503 Surface member 104 Backside sealant 105, 504 Backside member 201 Conductive substrate 202 Backside reflective layer 203 Semiconductor photoactive layer 204 Transparent conductive layer 205 Current collecting electrode 206a Positive output terminal 206b Negative output terminal 207 Conductive adhesive or solder 208 Solder 302, 402, 502 Sealant resin 303 Surface film 304, 404 Back film 305 Support plate 403 Glass

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 35/00 C08L 35/00 (72) Inventor Hidemitsu Zenko 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Hidenori Shiotsuka 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (21)

[Claims] 1. A solar cell module in which a light-receiving surface and / or a non-light-receiving surface of a photovoltaic element is sealed with an organic polymer resin layer, wherein at least one of the organic polymer resin layers is ethylene-acrylic. Acid ester-acrylic acid terpolymer, ethylene-acrylate-maleic anhydride terpolymer, ethylene-methacrylic ester-acrylic terpolymer, ethylene-acrylic ester-methacrylic ternary A solar cell module comprising any one of a copolymer, an ethylene-methacrylic acid ester-methacrylic acid terpolymer, an ethylene-methacrylic acid ester-maleic anhydride terpolymer, or a mixture thereof. . 2. The ethylene content of the terpolymer is 6
5-89.9% by weight, unsaturated fatty acid ester content is 1
0 to 30% by weight, and unsaturated fatty acid content is 0.1 to 5.0.
2. The solar cell module according to claim 1, wherein the weight is% by weight. 3. 3. The terpolymer has a Vicat softening point of 4
The temperature is between 0 ° C and 110 ° C.
Or the solar cell module according to 2. 4. The solar cell module according to claim 1, wherein the terpolymer contains a hindered amine light stabilizer. 5. The solar cell module according to claim 1, wherein the terpolymer contains an ultraviolet absorber. 6. The solar cell module according to claim 5, wherein the ultraviolet absorber is selected from a benzophenone derivative and a benzotriazole derivative. 7. The solar cell module according to claim 1, wherein the terpolymer contains a silane coupling agent. 8. The solar cell module according to claim 1, wherein the terpolymer contains a hindered phenol antioxidant. 9. The terpolymer according to claim 1, wherein the terpolymer has a total light transmittance at a thickness of 0.5 mm of at least 90% over the entire wavelength range of 400 to 1000 nm. A solar cell module according to item 1. 10. The method according to claim 1, wherein the acrylate is methyl acrylate, ethyl acrylate or (iso) butyl acrylate.
A solar cell module according to any one of the above. 11. The method according to claim 1, wherein the methacrylate is methyl methacrylate, ethyl methacrylate or (iso) butyl methacrylate.
10. The solar cell module according to any one of claims 9 to 9. 12. A semiconductor photoactive layer as a light conversion member, wherein the photovoltaic element is formed on a conductive substrate as a first electrode;
The solar cell module according to any one of claims 1 to 11, wherein a transparent conductive layer as a second electrode is formed. 13. The semiconductor photoactive layer comprises an amorphous semiconductor or a microcrystalline semiconductor.
3. The solar cell module according to 2. 14. The solar cell module according to claim 13, wherein said amorphous semiconductor is amorphous silicon or microcrystalline silicon. 15. The solar cell module according to claim 12, wherein the conductive substrate is made of stainless steel. 16. The solar cell module according to claim 1, wherein the short-circuit portion of the photovoltaic element has been repaired by a defect removing process. 17. The shunt resistance of the photovoltaic element is 1
The solar cell module according to any one of claims 1 to 16, wherein the kW · cm ² or more 500 k [Omega] · cm ² or less. 18. A collecting electrode containing copper or silver as one of the constituent elements is provided on the light-receiving surface side surface of the photovoltaic element, and the terpolymer is in contact with the collecting electrode. The solar cell module according to any one of claims 1 to 17, wherein the solar cell module is provided. 19. The photovoltaic element according to claim 1, wherein a light-receiving surface of said photovoltaic element is covered with said terpolymer and an outermost fluoride polymer thin film provided on said terpolymer. The solar cell module according to any one of the above. 20. The solar cell module according to claim 1, wherein the photovoltaic element is bonded to a building material via an adhesive layer. 21. The solar cell module according to claim 1, wherein a maximum use temperature is 80 ° C. or higher.