JP2006066761A - Solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar cell module in which even if it is used outdoors for a long period of time, an organic polymer resin for sealing of a light receiving surface side is hard to be yellowed and, as a result, a performance deterioration by an incident light decrease to the solar cell element caused by yellowing is suppressed, and simultaneously the light deterioration of a resin material provided at an element light receiving surface side is suppressed with high reliability. <P>SOLUTION: In the solar cell module in which the light receiving surface side of the solar cell element 1 is sealed by the organic polymer resin 4 and a transparent member 2 of its outside, an ultraviolet absorbing agent made of an organic compound, a hindered amine light stabilizer and a crosslinking agent made of an organic peroxide are contained in the organic polymer resin. The concentration of the ultraviolet absorbing agent contained in an organic polymer resin coating at least the part of the photoelectric conversion active region of the solar cell element is smaller than the concentration of the ultraviolet absorbing agent contained in the organic polymer resin coating at least the part of the solar cell element except the photoelectric conversion active region. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

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

  FIG. 3 is a schematic cross-sectional view showing the basic structure of the solar cell module. In FIG. 3, 1 is a solar cell element, 13 is an organic polymer resin, 2 is a translucent member, and 3 is a back surface protection member. Sunlight passes through the translucent member and the organic polymer resin, enters the light receiving surface of the solar cell element, and is converted into electric energy. The generated electricity is taken out from an output terminal (not shown).

  The solar cell element cannot withstand use in a harsh environment outdoors as it is. This is because the solar cell element itself is easily corroded and easily damaged by an external impact. Therefore, it is necessary to cover and protect the solar cell element with a sealing material. Most commonly, solar cell elements are transparent and weather-resistant translucent members such as glass and fluororesin film, and weather resistance, moisture resistance, and electrical insulation such as fluororesin film, aluminum laminated fluororesin film, and polyester film. A method of sandwiching and laminating an organic polymer resin with a back surface protection member excellent in properties is taken.

  As a conventional organic polymer resin for sealing a solar cell, polyvinyl butyral and ethylene-vinyl acetate copolymer (EVA) have been mainly used. Above all, EVA crosslinkable compositions have excellent characteristics in terms of heat resistance, weather resistance, transparency, cost, etc., and are currently the mainstream of organic polymer resins for sealing solar cells.

  Since the solar cell module is used outdoors for a long time, high durability is required. The durability of the solar cell element is of course, but excellent light resistance and heat resistance are also required for the sealing material. However, when exposed to the outdoors for more than 10 years, photodegradation and thermal degradation of the sealing material cannot be avoided, and yellowing of the organic polymer resin or peeling between the members may become apparent. The yellowing of the organic polymer resin causes a decrease in the amount of incident light, resulting in a decrease in electrical output. Further, peeling between the members causes corrosion of the solar cell element or a metal member attached to the element due to the intrusion of moisture into the peeling portion, leading to deterioration of the solar cell module performance.

  Various additives are blended in EVA conventionally used in order to prevent yellowing due to such deterioration and peeling from other members. Among them, UV absorbers, light stabilizers, and antioxidants play an important role. UV absorbers and light stabilizers cause light degradation caused by ultraviolet rays, and antioxidants cause thermal degradation. It contributes to the provision of highly reliable solar cell modules that are suppressed and have no performance degradation even when exposed outdoors for a long period of time.

  Further, the light deterioration is not limited to the sealing material, and the same applies to various resin materials provided on the light receiving surface side, and the ultraviolet absorber added to the sealing material absorbs ultraviolet rays that reach such a resin material. It also plays a role of blocking the light deterioration of the resin material.

  For example, as described in Patent Documents 1 to 3, etc., the UV absorber is 0.1 to 1.0 wt%, the light stabilizer is 0.05 to 1.0 wt%, and the antioxidant is 0 to EVA. It is disclosed that a blend of 0.05 to 1.0 wt% is suitably used as a sealing material for a solar cell module.

JP-A-8-139347 JP-A-10-93124 JP-A-10-112549

  However, as described above, even when a solar cell module sealed with EVA, which is light- and heat-resistant by adding additives, is used outdoors for a long period of time, the EVA on the light-receiving surface side turns yellow and the sun It has become clear that the performance of battery modules may be degraded.

  As a result of investigations to investigate the cause, the present inventor has found that the ultraviolet absorber added as an additive is the cause of yellowing. That is, it is considered that the ultraviolet absorber is changed to another compound that exhibits yellowing due to the interaction between the organic peroxide added to EVA as a crosslinking agent and ultraviolet rays. This is indirectly estimated from the fact that yellowing is reduced when the blending amount of the UV absorber is reduced, and that yellowing is promoted when the blending amount of the organic peroxide is increased. .

  Therefore, in order to solve the problem that the performance of the solar cell module is deteriorated due to yellowing of EVA, it is conceivable to reduce the blending amount of the ultraviolet absorber in EVA that seals the element light receiving surface side. In this case, it becomes impossible to block the ultraviolet rays that reach the resin material provided on the element light-receiving surface side, and light degradation of the resin material becomes obvious. Specifically, it appears as yellowing or cracking of the resin material. This is not only a problem in appearance, but may cause peeling between the resin material and the sealing material and a decrease in the insulation performance of the resin material, which may impair the quality reliability of the solar cell module.

  The present invention has been made in view of these circumstances, and even when used outdoors for a long period of time, the organic polymer resin that seals the photoelectric conversion active region on the light-receiving surface side is hardly yellowed. To provide a highly reliable solar cell module that suppresses performance degradation due to a decrease in incident light to the solar cell element due to yellowing and at the same time suppresses light deterioration of the resin material provided on the light receiving surface side of the element. Objective.

  As a result of intensive research and development to solve the above problems, the present inventor has found that the following configuration is the best.

  That is, the present invention relates to a solar cell module in which the light-receiving surface side of a solar cell element is sealed with an organic polymer resin and a translucent member on the outer side, and the organic polymer resin has an ultraviolet absorption made of an organic compound. Agent, a hindered amine light stabilizer, and a crosslinking agent composed of an organic peroxide, and contained in an organic polymer resin that covers at least a part of the photoelectric conversion active region of the solar cell element. The concentration of the ultraviolet absorber is smaller than the concentration of the ultraviolet absorber contained in the organic polymer resin covering at least a part other than the photoelectric conversion active region of the solar cell element.

In the solar cell module of the present invention, the concentration of the ultraviolet absorber contained in the organic polymer resin covering at least a part of the photoelectric conversion active region is 0.01% by weight or less, and other than the photoelectric conversion active region It is preferable that the concentration of the ultraviolet absorber contained in the organic polymer resin covering at least a part of is 0.1% by weight or more.
The concentration of the hindered amine light stabilizer contained in the organic polymer resin covering at least a part of the photoelectric conversion active region is preferably 0.5 to 1.0% by weight.

According to the present invention, even when used outdoors for a long period of time, the organic polymer resin that seals the photoelectric conversion active region on the light-receiving surface side is hardly yellowed. It is possible to provide a highly reliable solar cell module that suppresses the performance degradation due to the decrease in the incident light and at the same time suppresses the light deterioration of the resin material provided on the element light receiving surface side.
The concentration of the ultraviolet absorber contained in the organic polymer resin that covers at least a part of the photoelectric conversion active region is 0.01% by weight or less, and covers at least a part other than the photoelectric conversion active region. Organic polymer resin that seals the photoelectric conversion active region on the light-receiving surface side even if it is used outdoors for a long period of time because the concentration of the ultraviolet absorber contained in the organic polymer resin is 0.1% by weight or more As a result, it is possible to prevent deterioration in performance due to yellowing and to provide a highly reliable solar cell module free from light deterioration of the resin material provided on the element light receiving surface side. It becomes possible.
Furthermore, the concentration of the hindered amine light stabilizer contained in the organic polymer resin covering at least a part of the photoelectric conversion active region is 0.5 to 1.0% by weight, Yellowing can be suppressed more effectively.

  FIG. 1 shows an example of a schematic configuration diagram of a solar cell module of the present invention. In FIG. 1, 1 is a solar cell element, 4 is a surface sealing organic polymer resin, 2 is a translucent member, 5 is a back surface sealing organic polymer resin, 3 is a back surface protection member, and 6 is a bus bar. An electrode 7 is a collecting electrode.

  First, the sealing organic polymer resins 4 and 5 in the present invention will be described in detail below.

  The organic polymer resin 4 for surface sealing is necessary for covering the unevenness of the light receiving surface of the solar cell element with a resin and protecting the element from the external environment. Further, it also serves to adhere the translucent member 2 to the solar cell element 1. Therefore, in addition to high transparency, weather resistance, adhesiveness, and heat resistance are required. Materials satisfying such requirements include ethylene-vinyl acetate copolymer (EVA) resin, ethylene-methyl acrylate copolymer (EMA) resin, ethylene-ethyl acrylate copolymer (EEA) resin, ethylene- Examples include methacrylic acid copolymer (EMAA) resin, ionomer resin, polyvinyl butyral resin, and the like. Above all, EVA resin is suitably used because it has well-balanced physical properties for solar cell applications such as weather resistance, adhesiveness, filling property, heat resistance, cold resistance, and impact resistance.

  The organic polymer resin for surface sealing in the present invention contains an ultraviolet absorber made of an organic compound in order to enhance light resistance, and the organic polymer for surface sealing that covers at least a part of the photoelectric conversion active region. The concentration of the ultraviolet absorber contained in the resin is smaller than the concentration of the ultraviolet absorber contained in the organic polymer resin for surface sealing that covers at least a part other than the photoelectric conversion active region. The photoelectric conversion active region here refers to a region that absorbs light and performs photoelectric conversion in the region on the light receiving surface side of the solar cell element, and bears the output of the solar cell element. In the solar cell element, the region excluding the bus bar electrode and the current collecting electrode.

  The concentration of the ultraviolet absorber contained in the organic polymer resin for surface sealing covering at least a part of the photoelectric conversion active region is preferably 0.01% by weight or less with respect to the organic polymer resin. More preferably, it is 0.001% by weight or less. When the concentration exceeds 0.01% by weight, yellowing of the organic polymer resin becomes obvious during long-term outdoor exposure due to alteration of the ultraviolet absorber, and the performance of the solar cell module is deteriorated. On the other hand, if it is 0.01% by weight or less, the performance degradation due to yellowing can be suppressed to a negligible level, and the output does not decrease due to light loss due to the ultraviolet absorber. Furthermore, if it is 0.001% by weight or less, no performance deterioration due to yellowing is observed. Of course, the present invention can also adopt a configuration in which the concentration is 0% by weight, that is, an ultraviolet absorber made of an organic compound is not included.

  On the other hand, the concentration of the ultraviolet absorber contained in the organic polymer resin for surface sealing covering at least a part other than the photoelectric conversion active region should be 0.1% by weight or more with respect to the organic polymer resin. desirable. When the concentration is less than 0.1% by weight, the ultraviolet light cannot be sufficiently blocked by the organic polymer resin for surface sealing, and the light of the member disposed under the organic polymer resin layer for surface sealing Deterioration easily proceeds. The non-photoelectric conversion active region mentioned here specifically means, for example, a region provided with an electrode member such as a collecting electrode, a bus bar electrode, or an output extraction metal foil, an insulating tape, a design tape, etc. It refers to a region where a resin tape is provided, a region where a bypass diode is provided, a region where there is no solar cell element such as a gap between a plurality of solar cell elements or the periphery of a solar cell element. Among these, the member disposed under the surface sealing organic polymer resin layer in the region where there is no solar cell element such as a gap between a plurality of solar cell elements or the periphery of the solar cell element is an organic polymer resin for backside sealing. Since the photodegradation can also be prevented by increasing the concentration of the ultraviolet absorber contained in the layer, the effect of the present invention is limited. Other areas, that is, areas where electrode members such as current collecting electrodes, bus bar electrodes, metal foil for output extraction are provided, areas where resin tape such as insulating tape and design tape is provided, bypass diodes The area provided is particularly effective as an area other than the photoelectric conversion active area of the present invention, in which blocking of ultraviolet rays in the organic polymer resin layer for surface sealing is extremely effective for preventing light degradation of the member. It is.

  As the ultraviolet absorber composed of the organic compound used in the present invention, various conventionally known ones can be selected and used. For example, typical chemical structures of such ultraviolet absorbers are roughly classified into salicylic acid series, benzophenone series, benzotriazole series, cyanoacrylate series, and triazine series.

  Examples of salicylic acid systems include phenyl salicylate, p-tert-butylphenyl salicylate, and p-octylphenyl salicylate.

  In the benzophenone series, 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.

  Examples of the benzotriazole type include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-5′-tert-butylphenyl) benzotriazole, and 2- (2′-hydroxy-5). '-Octylphenyl) -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-amylphenyl) 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} Can be mentioned.

  Examples of cyanoacrylates include 2-ethylhexyl-2-cyano-3,3'-diphenyl acrylate and ethyl-2-cyano-3,3'-diphenyl acrylate.

Examples of triazines include 2- {4 ′, 6′-bis (2 ″, 4 ″ -dimethylphenyl) -1 ′, 3 ′, 5′-triazine-2′-yl} -5- (octyloxy) phenol Is mentioned.
A hindered amine light stabilizer is added to the organic polymer resin for surface sealing of the present invention in order to enhance light resistance and heat resistance and to provide sufficient durability for outdoor use. A hindered amine light stabilizer does not absorb ultraviolet rays like an ultraviolet absorber, but inhibits a degradation reaction by capturing radical species generated in the process of photodegradation or thermal degradation of an organic polymer resin. The addition amount is usually about 0.1 to 0.3% by weight. In the present invention, the ultraviolet ray contained in the organic polymer resin for surface sealing that covers at least a part of the photoelectric conversion active region. The addition amount of the absorbent is small, and the resin is exposed to a lot of ultraviolet rays. Therefore, it is desirable to add more light stabilizer than usual to enhance the durability against light degradation, and the hindered amine light contained in the organic polymer resin covering at least a part of the photoelectric conversion active region. The amount of stabilizer added to the organic polymer resin is preferably 0.5 to 1.0% by weight. If the added amount exceeds 1.0% by weight, the organic polymer resin is likely to be whitened by bleed-out of the light stabilizer, which is not desirable. In addition to hindered amines, there are those that function as light stabilizers, but they are often colored and are not preferred for the organic polymer resin for surface sealing of the present invention.

  As the hindered amine light stabilizer, dimethyl-1- (2-hydroxyethyl) succinate-4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [{6- (1,1,1, 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) sevalate, 2- (3 5-di-tert-4-hi Rokishibenjiru) -2-n-butyl malonic acid bis (1,2,2,6,6-pentamethyl-4-piperidyl) and the like are known.

  The organic polymer resin for surface sealing is cross-linked with an organic peroxide in order to prevent softening and flowing under high temperature use conditions and to improve adhesion to other members. Crosslinking with an organic peroxide is performed by free radicals generated from the organic peroxide drawing hydrogen in the resin to form a C—C bond. Thermal decomposition, redox decomposition and ionic decomposition are known as organic peroxide activation methods. In general, the thermal decomposition method is preferred. That is, a sheet of an organic polymer resin to which an organic peroxide has been added in advance is prepared, and this is thermocompression bonded to the solar cell element, and at the same time, crosslinking proceeds.

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

  Hydroperoxides include t-butyl peroxide, 1,1,3,3-tetramethylbutyl peroxide, p-menthane hydroperoxide, cumene hydroperoxide, p-cymene hydroperoxide, diisopropylbenzene peroxide, 2,5-dimethylhexane 2 , 5-dihydroperoxide, cyclohexane peroxide, 3,3,5-trimethylhexanone peroxide and the like.

  Examples of the dialkyl (allyl) peroxide include di-t-butyl peroxide, dicumyl peroxide, and t-butylcumyl peroxide.

  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.

  Examples of peroxyketals include 2,2-di-t-butylperoxybutane, 1,1-di-t-butylperoxycyclohexane, 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-butyl) Peroxyisopropyl) benzene, 2,5-dimethyl-2,5-dibenzoylperoxyhexane, 2,5-dimethyl-2,5-di (peroxybenzoyl) hexyne-3, n-butyl-4,4-bis (t -Butylperoxy) valerate.

  Examples of peroxyesters include t-butyl peroxyacetate, t-butylperoxyisobutyrate, t-butylperoxypivalate, t-butylperoxyneodecanoate, t-butylperoxy3,3,5-trimethylhesanoate, t-butylperoxy 2-ethylhexanoate, (1,1,3,3-tetramethylbutylperoxy) 2-ethylhexanoate, t-butylperoxylaurate, t-butylperoxybenzoate, di (t-butyl) Peroxy) adipate, 2,5-dimethyl2,5-di (peroxy-2-ethylhexanoyl) hexane, di (t-butylperoxy) isophthalate, t-butylperoxymalate, acetylcyclohexylsulfonyl peroxide, and the like.

  Examples of peroxycarbonates include t-butylperoxyisopropyl carbonate, di-n-propylperoxydicarbonate, di-sec-butylperoxydicarbonate, di (isopropylperoxy) dicarbonate, di (2-ethylhexylperoxy) dicarbonate, Examples include di (2-ethoxyethylperoxy) dicarbonate, di (methoxyidpropylperoxy) carbonate, di (3-methoxybutylperoxy) dicarbonate, bis- (4-t-butylcyclohexylperoxy) dicarbonate and the like.

  Examples of the ketone peroxide include acetylacetone peroxide, methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, and ketone peroxide. In other structures, vinyltris (t-butylperoxy) silane is also known.

  The amount of the organic peroxide added is about 1.0 to 5.0% by weight with respect to the organic polymer resin.

  It is possible to mix the organic peroxide with an organic polymer resin and perform crosslinking and sealing 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. In general, the heating is completed at a temperature and time at which thermal decomposition proceeds 90%, more preferably 95% or more.

  In order to efficiently perform the crosslinking reaction, triallyl cyanurate called a crosslinking aid can be used. Generally, the addition amount is 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the resin.

  A thermal antioxidant is often added to the organic polymer resin for sealing in order to impart stability at high temperatures. The addition amount is suitably 0.1 to 1.0 part by weight with respect to 100 parts by weight of the resin. The chemical structure of the antioxidant is roughly divided into a monophenol type, a bisphenol type, a polymer type phenol type, a sulfur type, and a phosphoric acid type.

  In the monophenol type, there are 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, and 2,6-di-tert-butyl-4-ethylphenol.

  In the bisphenol type, 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2′-methylene-bis- (4-ethyl-6-tertbutylphenol), 4,4′-thiobis -(3-methyl-6-tert-butylphenol), 4,4'-butylidene-bis- (3-methyl-6-tert-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 high molecular weight phenolic group, 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- {methylene-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, triphenol (vitamin E) are known.

  On the other hand, in the sulfur type, there are dilauryl thiodipropionate, dimyristyl thiodipropionate, distearyl thiopropionate, and the like.

  In the phosphoric acid system, triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, 4,4′-butylidene-bis- (3-methyl-6-tert-butylphenyl-di-tridecyl) phosphite, cyclic neo Pentanetetraylbis (octadecyl phosphite), tris (mono and or diphenyl phosphite), diisodecyl pentaerythritol diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenathlene-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-phosphafe Sullen, cyclic neopentanetetrayl bis (2,4-di-tert-butylphenyl) phosphite, cyclic neopentanetetrayl bis (2,6-di-tert-methylphenyl) phosphite, 2,2- There is methylene bis (4,6-tert-butylphenyl) octyl phosphite.

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

  When the use of a solar cell module is assumed in a more severe environment, it is preferable to improve the adhesive force between the organic polymer resin and the solar cell element or the translucent member. The adhesion can be improved by adding a silane coupling agent or an organic titanate compound to the organic polymer resin. Specific examples of the silane coupling agent include vinyltrichlorosilane, vinyltris (βmethoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl). ) Ethyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-amino Examples include propyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-chloropropyltrimethoxysilane.

  The back surface sealing organic polymer resin 5 is necessary for covering the unevenness of the back surface of the solar cell element with a resin and protecting the element from the external environment. Further, it also serves to adhere the back surface protection member 3 to the solar cell element 1. Accordingly, since weather resistance, adhesiveness, and heat resistance are required in the same manner as the organic polymer resin for surface sealing, a material suitable as the organic polymer resin for surface sealing can be used as the organic polymer resin for back surface sealing. It is preferable to use it. Usually, the same material as the organic polymer resin for surface sealing is used for the organic polymer resin for back surface sealing. Further, as with the organic polymer resin for surface sealing, additives such as an ultraviolet absorber, a light stabilizer, and a crosslinking agent are usually blended, and the amount of addition is in accordance with the organic polymer resin for surface sealing. However, the organic polymer resin for backside sealing has a high concentration because it does not affect the performance of the solar cell module even if it turns yellow and prevents the backside protective member described later from being photodegraded by ultraviolet rays. It is desirable to mix an ultraviolet absorber, and the addition amount is preferably 0.1 to 1.0% by weight with respect to the organic polymer resin. Accordingly, it is not necessary to use a material having excellent light resistance such as a fluororesin film as the back surface protection member, and an inexpensive material can be used as the back surface protection member although the light resistance is slightly inferior. On the other hand, since transparency is not essential, it is possible to add a filler such as an inorganic oxide to improve weather resistance and mechanical strength, and it may be colored with a pigment or the like.

  Hereinafter, each member which comprises a solar cell module is demonstrated.

  As the solar cell element 1, 1) a crystalline silicon solar cell, 2) a polycrystalline silicon solar cell, 3) a microcrystalline silicon solar cell, 4) an amorphous silicon solar cell, 5) a copper indium selenide solar cell, 6) a compound semiconductor Various conventionally known elements such as solar cells may be selected and used according to the purpose. A plurality of these solar cell elements are connected in series or in parallel according to a desired voltage or current. Alternatively, a desired voltage or current can be obtained by integrating solar cell elements on an insulated substrate. Further, a bypass diode is connected to the element as necessary in order to prevent reverse bias application to the element.

  Since the translucent member 2 is located on the outermost layer of the solar cell module, it requires performance for ensuring long-term reliability in outdoor exposure of the solar cell module, including weather resistance, contamination resistance, and mechanical strength. Examples of the member suitably used in the present invention include a (reinforced) glass plate and a fluoride polymer film. As the glass plate, it is preferable to use white plate glass having a high light transmittance. Specific examples of the fluoride polymer film include tetrafluoroethylene-ethylene copolymer (ETFE), polyvinyl fluoride resin (PVF), polyvinylidene fluoride resin (PVDF), polytetrafluoroethylene resin (TFE), There are tetrafluoroethylene-hexafluoropropylene copolymer (FEP) and polytrifluoroethylene chloride (CTFE). Polyvinylidene fluoride resin is excellent in terms of weather resistance, but tetrafluoroethylene-ethylene copolymer is excellent in terms of both weather resistance and mechanical strength. In order to improve the adhesion 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 in order to improve mechanical strength.

  The back surface protection member 3 is used for protecting the solar cell element, preventing moisture from entering, and maintaining electrical insulation from the outside. As a material, a material that can ensure sufficient electrical insulation, has excellent long-term durability, and can withstand thermal expansion and contraction is preferable. Examples of suitable materials include nylon film, polyethylene terephthalate (PET) film, polyvinyl fluoride (PVF) film, and glass plate. When the film is required to have moisture resistance, an aluminum laminated PVF film, an aluminum deposited PET film, a silicon oxide deposited PET film, or the like is used. Furthermore, 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 can be used as a back surface protection member.

  A support plate may be attached to the outside of the back surface protection member in order to increase the mechanical strength of the solar cell module or to prevent distortion and warping due to temperature changes. For example, there are a metal plate, a plastic plate, an FRP (glass fiber reinforced plastic) plate, a ceramic plate, and the like. Moreover, it can also be set as a building material integrated solar cell module by sticking a building material. As the building material, various materials can be selected from metal plates, slate boards, gypsum boards, tiles, glass fiber reinforced plastics, glass, and the like.

  Next, a method for forming a solar cell module using the solar cell element, the organic polymer resin for surface sealing, the organic polymer resin for back surface sealing, the translucent member, and the back surface protective member described above will be described.

  First, the front and back surface sealing organic polymer resins molded into a sheet are disposed on the light receiving surface side and the back surface side of the solar cell element, respectively. At this time, two kinds of sheets having different ultraviolet absorber contents were prepared as the organic polymer resin sheet for surface sealing, and a sheet having a low ultraviolet absorber content was formed in the photoelectric conversion active region of the solar cell element. In addition to the conversion active region, a sheet having a high ultraviolet absorber content is provided. Furthermore, it is set as the laminated body which has arrange | positioned the translucent member and the back surface protection member on the light-receiving surface side and the back surface side, respectively. A solar cell module can be obtained by heat-pressing this under reduced pressure using a vacuum laminator. In addition, it can be produced by roll lamination or the like.

  Hereinafter, the solar cell module of the present invention will be described in detail based on examples.

Example 1
An amorphous silicon solar cell (solar cell element) having a back surface reflection layer, a semiconductor photoactive layer, and a transparent electrode layer sequentially formed on a conductive substrate, and having a comb-shaped collector electrode and a bus bar electrode connected thereto on the transparent electrode layer A method for producing a solar cell module according to the first embodiment of the present invention will be described below with reference to FIG.

  A plurality of solar cell elements 1 are connected in series to form a solar cell element serial body 8, and an output extraction electrode (not shown) made of copper foil is attached to an electrode provided on the solar cell element at the end of the series. Further, a bypass diode (not shown) is attached to the solar cell element to prevent reverse bias application to the element. A white polyester tape 15 is attached to the bus bar electrode so as to cover the bus bar electrode in consideration of design.

  Next, the sealing organic polymer resin, the translucent member, and the back surface protecting member for sealing the solar cell element serial body 8 will be described.

  The organic polymer resin for surface sealing is an ethylene-vinyl acetate copolymer (EVA) resin pellet (vinyl acetate content 33 wt%) for sealing a photoelectric conversion active region of a solar cell element, and 2,5 as a crosslinking agent. -1.5% by weight of dimethyl-2,5-bis (t-butylperoxy) hexane, 1.0% by weight of γ-methacryloxypropyltrimethoxysilane as a silane coupling agent, and 2-hydroxy-4 as an ultraviolet absorber -0.01% by weight of n-octoxybenzophenone, 0.5% by weight of bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate as a light stabilizer, and tris (mono-nonyl) as an antioxidant Each of the additions of 0.2% by weight of phenyl) phosphite was melted by heating and extruded from a slit of a T-die to form a 400 μm thick sheet. A sheet-like EVA (hereinafter referred to as EVA sheet) 14 is encapsulated in ethylene-vinyl acetate copolymer (EVA) resin pellets (vinyl acetate content 33 wt%) for sealing other than the photoelectric conversion active region, and 2, 5-dimethyl-2,5-bis (t-butylperoxy) hexane 1.5% by weight, γ-methacryloxypropyltrimethoxysilane 1.0% by weight as a silane coupling agent, and 2-hydroxy- as an ultraviolet absorber 4-n-octoxybenzophenone 0.3% by weight, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate 0.2% by weight as light stabilizer, tris (mono-) as antioxidant Nonylphenyl) Phosphite 0.2 wt% added, melted by heating, extruded from the slit of the T-die, and formed into a thickness of 400 μm The EVA sheet 11 is used.

  As the back surface sealing organic polymer resin, the same EVA sheet 12 as that used for surface sealing other than the photoelectric conversion active region is used.

  A white plate tempered glass 9 having a thickness of 3.2 mm is used as the translucent member, and a polyethylene terephthalate (PET) film 10 having a thickness of 100 μm is used as the back surface protective member.

  The solar cell element serial body 8, the EVA sheets 11, 12, 14, the glass 9, and the PET film 10 are laminated in the configuration shown in FIG. That is, the surface sealing EVA sheets 11 and 14 and the glass 9 are stacked on the light receiving surface side of the solar cell element series body, and the back surface sealing EVA sheet 12 and the PET film 10 are stacked on the back surface side to form a laminate, and a vacuum laminator. The solar cell element is sealed by thermocompression bonding at 150 ° C. for 30 minutes. At this time, by stacking the EVA sheet 11 on the bus bar electrode of the solar cell element as shown in FIG. The photoelectric conversion active region on the light-receiving surface side of the solar cell element and the region that is not so can be sealed with the EVA sheet 14 and the EVA sheet 11, respectively.

  An output extraction electrode (not shown) is led out from an opening provided in the back surface sealing EVA sheet and the PET film in advance.

The solar cell module produced by the above method was irradiated with ultraviolet rays having an irradiation intensity of 1.50 kW / m ² in a wavelength region of 300 to 400 nm for 1000 hours with a metal halide lamp. During the irradiation, the atmosphere was controlled so that the black panel temperature was 63 ° C. and the humidity was 50% RH.

  The electrical characteristics of the solar cell element series before sealing and the solar cell module before and after the irradiation test were measured with a solar simulator, and the output of the solar cell module before and after the test and the relative value of the short-circuit current with 1 before the sealing. Is shown in Table 1. Further, the appearance of the solar cell module after the test was observed, and the results are also shown in Table 1. The number of samples is 10, and the data is the average value.

(Example 2)
In Example 1, a solar cell module was produced in the same manner except that no UV absorber was added to the EVA sheet for sealing the photoelectric conversion active region, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

(Example 3)
A solar cell module was produced in the same manner as in Example 2, except that the translucent member was changed to an ethylene-tetrafluoroethylene copolymer (ETFE) film having a thickness of 50 μm obtained by subjecting the adhesive surface to EVA to a discharge treatment. The same evaluation as in Example 1 was performed. The results are shown in Table 2.

Example 4
In Example 2, a solar cell module was produced in exactly the same manner as in Example 1 except that the amount of light stabilizer added to the EVA sheet for sealing the photoelectric conversion active region was 1.0% by weight. Evaluation was performed. The results are shown in Table 1.

(Example 5)
In Example 2, a solar cell module was prepared in exactly the same manner as in Example 1 except that the amount of light stabilizer added to the EVA sheet for sealing the photoelectric conversion active region was 0.3% by weight. Evaluation was performed. The results are shown in Table 1.

(Example 6)
In Example 2, a solar cell module was produced in exactly the same manner as in Example 1 except that the amount of light stabilizer added to the EVA sheet for sealing the photoelectric conversion active region was 1.2% by weight. Evaluation was performed. The results are shown in Table 1.

(Comparative Example 1)
In Example 2, the EVA sheet 14 for photoelectric conversion active region sealing was used for sealing other than the photoelectric conversion active region. Except that, a solar cell module was produced in the same manner, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

(Comparative Example 2)
In Example 3, the EVA sheet 14 for photoelectric conversion active region sealing was used for sealing other than the photoelectric conversion active region. Except that, a solar cell module was produced in the same manner, and the same evaluation as in Example 1 was performed. The results are shown in Table 2.

  In order to facilitate the comparison between the examples and the comparative examples, the following is a table in which the solar cell modules are classified by the translucent member and the data are summarized.

  As is clear from Tables 1 and 2, the solar cell module in which the present invention was implemented was not degraded in yellow due to yellowing of the EVA covering the photoelectric conversion active region with respect to long-term ultraviolet irradiation. There is almost no.

  In Example 1, it is surmised that the decrease in short-circuit current is slightly larger than in Examples 2 and 4, and EVA is yellowed to the extent that it cannot be visually observed, but the effect on the output is negligible. There is no problem in actual use.

  In Example 5, the amount of light stabilizer added was small, so the EVA slightly turned yellow, and in Example 6, the amount of light stabilizer added was large, so the EVA extreme due to light stabilizer bleed out. A slight amount of white turbidity is generated, and the short-circuit current is greatly reduced as compared with Examples 2 and 4. However, this is also slightly the same as in Example 1, and there is no practical problem.

  Further, in Examples 1, 2, 4, 5, and 6, no change was observed in the polyester tape provided on the bus bar, and a solar cell module excellent in light resistance without deterioration of the member due to light could be obtained. .

  In Example 3, the translucent member was changed from glass to ETFE, but the yellowing of EVA and the change of the polyester tape were not recognized as in the case of glass.

  In Example 3, since an ETFE film is used as the translucent member, the reflection loss on the surface is smaller than that of glass, and the output before the test is larger than that of the example using glass.

  On the other hand, as is apparent from Table 1, although EVA yellowing was not observed in Comparative Example 1, the EVA covering the areas other than the photoelectric conversion active region did not contain an ultraviolet absorber. The provided polyester tape was extremely yellowed, and it was difficult to say that the appearance was preferable.

  In Comparative Example 2, as in Comparative Example 1, there was no yellowing of EVA, and no performance degradation due to yellowing was observed, but the EVA covering the areas other than the photoelectric conversion active region contained no UV absorber. The polyester tape provided on the electrode was noticeably yellowed. The degree of yellowing was worse than in Comparative Example 2. In addition, innumerable micro cracks were generated on the surface of the polyester tape, and in some cases, peeling occurred between the polyester tape and the organic polymer resin for surface sealing. This is presumably because the surface member is an ETFE film excellent in ultraviolet transmittance, so that much more ultraviolet rays reached the polyester tape than Comparative Example 2 in which the surface member was glass.

It is the schematic plan view and schematic sectional drawing of one Embodiment of the solar cell module which implemented this invention. FIG. 3 is a schematic plan view and a schematic cross-sectional view showing a manufacturing process of the solar cell module of Example 1. It is the schematic plan view and schematic sectional drawing which show an example of the conventional solar cell module.

Explanation of symbols

1: Solar cell element 2: Translucent member 3: Back surface protection member 4: Organic polymer resin for surface sealing 5: Organic polymer resin for back surface sealing 6: Bus bar electrode 7: Current collecting electrode 8: Solar cell element Serial body 9: Glass (translucent member)
10: PET film 11: EVA sheet for sealing other than photoelectric conversion active region 12: EVA sheet for back surface sealing 13: Organic polymer resin 14: EVA sheet for sealing photoelectric conversion active region 15: Polyester tape

Claims (2)

  In a solar cell module in which a light receiving surface side of a solar cell element is sealed with an organic polymer resin and a translucent member on the outside thereof, the organic polymer resin includes an ultraviolet absorber made of an organic compound, and hindered amine light. The concentration of the ultraviolet absorber contained in the organic polymer resin that contains a stabilizer and a crosslinking agent composed of an organic peroxide and covers at least a part of the photoelectric conversion active region of the solar cell element Is 0.01% by weight or less, and the concentration of the ultraviolet absorber contained in the organic polymer resin covering at least a part other than the photoelectric conversion active region of the solar cell element is 0.1% by weight or more. A solar cell module characterized by that.   The concentration of the hindered amine light stabilizer contained in the organic polymer resin covering at least a part of the photoelectric conversion active region is 0.5 to 1.0% by weight. Solar cell module.

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