JP4890752B2 - Solar cell module - Google Patents

Description

  The present invention relates to a solar cell module, and more particularly to a solar cell module in which the front and back surfaces of a solar cell element are 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, 3 is a back surface protection member, and 6 is a bus bar electrode. 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, and the electrical output decreases. 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.

  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. .

  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 for sealing on the light-receiving surface side is hardly yellowed, resulting in yellowing. An object of the present invention is to provide a highly reliable solar cell module that suppresses performance degradation due to a decrease in incident light on the solar cell element.

  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 provides 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 outside thereof, and the hindered amine light stabilizer is added to the organic polymer resin. When, and a crosslinking agent comprising an organic peroxide which is contained, the concentration of an organic compound contained in the organic polymer resin UV absorber Ri der 0.001 wt% or less, of the solar cell element The non-light-receiving surface side is sealed with an organic polymer resin and an outer back surface protective member on the outer side, and the organic polymer resin on the non-light-receiving surface side has a higher concentration of ultraviolet light than the organic polymer resin on the light-receiving surface side. An absorbent is contained .

In the solar cell module of the present invention, arbitrary it is preferable that the concentration of hindered amine light stabilizer contained in the organic polymer resin of the light receiving surface side is 0.5 to 1.0 wt%.

According to the present invention, even when used outdoors for a long period of time, the organic polymer resin for sealing on the light-receiving surface side is hardly yellowed, and as a result, the incident light on the solar cell element is reduced due to yellowing. It is possible to provide a highly reliable solar cell module that suppresses performance degradation.
In addition, when the concentration of the ultraviolet absorber is 0.001% by weight or less, the organic polymer resin for sealing on the light-receiving surface side is not yellowed even when used outdoors for a long time. It is possible to provide a highly reliable solar cell module that does not cause performance degradation due to yellowing.
Moreover, when the concentration of the hindered amine light stabilizer is 0.5 to 1.0% by weight, yellowing of the organic polymer resin can be effectively suppressed.
Furthermore, the non-light-receiving surface side of the solar cell element is sealed with an organic polymer resin and a back surface protective member outside thereof, and the organic polymer on the light-receiving surface side is sealed with the organic polymer resin on the non-light-receiving surface side. By containing the ultraviolet absorber at a higher concentration than the resin, it is possible to prevent deterioration of the back surface protection member due to ultraviolet rays and to provide a more reliable solar cell module.

  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 may contain an ultraviolet absorber made of an organic compound in order to enhance light resistance, but its concentration is 0.01% by weight or less, more preferably 0.001% by weight. 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 if it is 0.001% by weight or less, the performance degradation due to yellowing is not recognized. 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.

  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 2- (4 ′, 6′-diphenyl-1 ′, 3 ′, 5′-triazin-2′-yl) -5- (hexyloxy) phenol.

  Of these, benzophenone, benzotriazole, and triazine UV absorbers are preferably used in consideration of compatibility with organic polymer resins and the stability of the UV absorber itself, and low volatility is considered. It is more preferable to use a triazine-based ultraviolet absorber.

  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, but in the present invention, the addition amount of the ultraviolet absorber is small and the resin is exposed to a large amount of ultraviolet rays. Therefore, it is desirable to add more light stabilizer than usual to increase the durability against light deterioration, and the addition amount is desirably 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) sebacate, bis (1,2 , 2,6,6-pentame Ru-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) [{3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl} methyl] butyl Malonate, N, N ′, N ″, N ′ ″-tetrakis- (4,6-bis- (butyl- (N-methyl-2,2,6,6-tetramethylpiperidin-4-yl) Amino) -triazin-2-yl) -4,7-diazadecane-1,10-diamine, dibutylamine, 1,3,5-triazine, N, N′-bis (2,2,6,6-tetramethyl) A polycondensate of -4-piperidyl-1,6-hexamethylenediamine and N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine is 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 peroxides, diacyl peroxides, peroxyketals, alkyl peroxyesters, peroxycarbonates, peroxydicarbonates, and ketone peroxides according to chemical structures.

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

  Dialkyl peroxides include di-t-butyl peroxide, dicumyl peroxide, t-butyl cumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5- Dimethyl-2,5-di (t-butylperoxy) hexyne-3,1,3-di (2-t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-dibenzoylperoxyhexane 2,5-dimethyl-2,5-di (peroxybenzoyl) hexyne-3, di-t-amyl peroxide and the like.

  Diacyl peroxides include diacetyl peroxide, dipropionyl peroxide, diisobutyryl peroxide, dioctanoyl peroxide, didecanoyl peroxide, dilauroyl peroxide, diisononanoyl peroxide, di (3, 3, 5-trimethylhexanoyl) peroxide, dibenzoyl peroxide, di (m-toluyl) peroxide, di (p-chlorobenzoyl) peroxide, 2,4-dichlorobenzoyl peroxide, peroxysuccinic acid, and the like.

  As peroxyketal type, 2,2-di (t-butylperoxy) butane, 1,1-di (t-butylperoxy) cyclohexane, 1,1-di (t-butylperoxy) -3,3 , 5-trimethylcyclohexane, n-butyl-4,4-di (t-butylperoxy) valerate, ethyl-3,3-di (t-butylperoxy) butyrate, and the like.

  Examples of alkyl peroxyesters include t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxypivalate, t-butyl peroxyneodecanoate, t-butyl peroxy 3, 3, 5-trimethylhesanoate, t-butylperoxy 2-ethylhexanoate, (1,1,3,3-tetramethylbutylperoxy) 2-ethylhexanoate, t-butylperoxylaurate, t -Butyl peroxybenzoate, di (t-butylperoxy) adipate, 2,5-dimethyl 2,5-di (peroxy 2-ethylhexanoyl) hexane, di (t-butylperoxy) isophthalate, t-butyl Peroximalate, acetylcyclohexylsulfonyl peroxide, and the like.

  Examples of peroxycarbonates include t-butyl peroxyisopropyl carbonate, di-n-propyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, di (isopropylperoxy) dicarbonate, di (2-ethylhexylperoxy). ) Dicarbonate, di (2-ethoxyethylperoxy) dicarbonate, di (methoxidepropylperoxy) carbonate, di (3-methoxybutylperoxy) dicarbonate, bis- (4-t-butylcyclohexylperoxy) Examples include dicarbonate.

  Examples of the ketone peroxide include acetylacetone peroxide, methyl ethyl ketone peroxide, and methyl isobutyl 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.

  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).

  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.

  For phosphoric acid, 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-nonylphenyl phosphite), diisodecyl pentaerythritol diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenalene-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-fo Phaphenanthrene, cyclic neopentanetetraylbis (2,4-di-tert-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,6-di-tert-methylphenyl) phosphite, 2 , 2-methylenebis (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 back surface sealing does not affect the performance of the solar cell module even if it turns yellow, and the back surface protection member described later prevents the surface protection member from being photodegraded by ultraviolet rays. It is desirable to blend the UV absorber at a higher concentration than the organic polymer resin for use, and the addition amount is preferably 0.1 to 1.0% by weight. 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, roof 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, an organic polymer resin for sealing the front and back surfaces molded into a sheet shape is disposed on the light receiving surface side and the back surface side of the solar cell element, respectively, and further, a translucent member and a back surface protection member are respectively provided on the outside of the light receiving surface side. And a laminated body arranged on the back side. 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 [Reference Comparative Example] )
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 ) will be described below with reference to FIG. 2 a method of making a solar cell module used.

  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.

  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 includes ethylene-vinyl acetate copolymer (EVA) resin pellets (vinyl acetate content 33 wt%) and 2,5-dimethyl-2,5-di (t- Butylperoxy) hexane 1.5% by weight, γ-methacryloxypropyltrimethoxysilane 1.0% by weight as a silane coupling agent, 2-hydroxy-4-n-octoxybenzophenone 0.01% by weight as an ultraviolet absorber Bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate 0.5% by weight as a light stabilizer and 0.2% by weight tris (mono-nonylphenyl) phosphite as an antioxidant A sheet-like EVA (hereinafter referred to as EVA sheet) 11 having a thickness of 400 μm formed by heating and melting the added material and extruded from a slit of a T die is used. The

  For the back surface sealing organic polymer resin, the same EVA sheet 12 as that used for front surface sealing is used except that no ultraviolet absorber is added.

  A white plate tempered glass 9 having a thickness of 3.2 mm is used as the translucent member, and a polyvinyl fluoride (PVF) 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 and 12, the glass 9, and the PVF film 10 are laminated with the configuration shown in FIG. That is, the surface sealing EVA sheet and glass are stacked on the light receiving surface side of the solar cell element series body, and the back surface sealing EVA sheet and PVF film are stacked on the back surface side to form a laminated body, which is 30 ° C. at 150 ° C. with a vacuum laminator. The solar cell element is sealed by thermocompression bonding for a minute.

  An output extraction electrode (not shown) is led out from an opening provided in the back surface sealing EVA sheet and the PVF 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 [Reference Example] )
A solar cell module was prepared in the same manner as in Example 1 except that the amount of the UV absorber added to the EVA sheet for surface sealing was 0.001% by weight, and the same evaluation as in Example 1 was made. went. The results are shown in Table 1.

(Example 3 [Reference Example] )
In Example 1, a solar cell module was produced in exactly the same manner as in Example 1 except that the addition amount of the UV absorber added to the EVA sheet for surface sealing was 0% by weight, that is, it was not added. went. The results are shown in Table 1.

(Example 4 [Reference Example] )
A solar cell module was produced in the same manner as in Example 3 except that the translucent member was changed to an ethylene-tetrafluoroethylene copolymer (ETFE) film having a thickness of 50 μm in which the adhesive surface with EVA was subjected to discharge treatment. The same evaluation as in Example 1 was performed. The results are shown in Table 2.

(Example 5 [Reference Example] )
In Example 3, a polycrystalline silicon solar cell was used as the solar cell element. 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 3.

(Example 6 [Reference Example ])
In Example 1, the addition amount of the ultraviolet absorber blended in the backside sealing EVA sheet was 0.3 wt%, and a polyethylene terephthalate (PET) film having a thickness of 100 μm was used as the back surface protection member. Except that, a solar cell module was produced in the same manner, and the same evaluation as in Example 1 was performed and the appearance was observed. As a result, no change was observed.

(Comparative Example 1)
A solar cell module was produced in the same manner as in Example 1 except that the amount of the UV absorber added to the surface sealing EVA sheet was 0.3% by weight, and the same evaluation as in Example 1 was made. went. The results are shown in Table 1.

(Comparative Example 2)
In Example 1, the light stabilizer was not added to the EVA sheet for surface sealing. 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 3)
In Example 4, a solar cell module was produced in exactly the same manner except that the amount of the ultraviolet absorber added to the surface sealing EVA sheet was 0.3% by weight, and the same evaluation as in Example 1 was performed. went. The results are shown in Table 2.

(Comparative Example 4)
In Example 5, a solar cell module was prepared in exactly the same manner except that the amount of the UV absorber added to the surface sealing EVA sheet was 0.3% by weight, and the same evaluation as in Example 1 was performed. went. The results are shown in Table 3.

  In order to facilitate the comparison between the examples and the comparative examples, the solar cell modules are classified according to the type of the solar cell element and the translucent member, and the data is summarized in the following table.

  As is clear from Tables 1, 2, and 3, the solar cell module embodying the present invention is not subject to yellowing of the EVA on the light receiving surface side even when irradiated with ultraviolet rays for a long time. There is almost no decline.

  In Example 1, it is surmised that the short-circuit current is slightly lower than in Examples 2 and 3, and EVA is yellowed to the extent that it is not visually recognized. However, the influence on the output is negligible. There is no problem in actual use.

  Moreover, in Example 4, although the translucent member was changed from glass to ETFE, yellowing of EVA is not recognized like glass.

  In Example 5, a polycrystalline silicon solar cell was used as the solar cell element. However, similar to amorphous silicon, EVA yellowing after the test was not observed, and the output decreased slightly before and after the test.

  In Example 4, since the 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 clear from Tables 1 and 3, in Comparative Examples 1, 2 and 4 using glass as a translucent member, yellowing of EVA becomes obvious, and similarly compared to the corresponding examples using glass. The performance was greatly reduced.

  In Comparative Examples 1 and 4, EVA is yellowed on the element light-receiving surface side. On the other hand, no yellowing is observed on the element back side or outside the element. As described above, the cause of the EVA yellowing can be the alteration of the ultraviolet absorber due to the interaction with the organic peroxide remaining in the EVA. It is presumed that yellowing does not easily occur because the organic peroxide remaining through the PVF film as the back surface protecting member escapes from the outside of the device.

  In Comparative Example 2, EVA is greatly yellowed throughout. That is, since there is no suppression of light deterioration and heat deterioration by the light stabilizer, it is considered that the whole EVA has turned yellow.

  In Comparative Example 3, there is no EVA yellowing, and no performance degradation due to yellowing is observed. This is presumably because the organic peroxide is released from the ETFE film, which is a translucent member, and the oxygen permeability of the ETFE film is large. In other words, by giving a certain degree of oxygen permeability to the transparent surface protection film located on the outermost surface on the light incident side, the chemical structure that develops yellowing such as a conjugated double bond generated in the encapsulant resin is oxygen. This is because the so-called “photo bleach” phenomenon, which is eliminated by the above, can suppress the yellowing of the encapsulant resin placed between the surface protection film and the solar cell element in long-term outdoor exposure and accelerated weathering tests. is there. For these reasons, when the translucent member is an ETFE film, the yellowing of EVA is inherently unlikely to occur, and the yellowing suppressing effect according to the present invention cannot be expected. However, as is clear from Table 2, when Example 4 which is an amorphous silicon solar cell module using an ETFE film as a translucent member is compared with Comparative Example 3, the output before the test is larger in Example 4. I understand that. Amorphous silicon solar cells have a higher spectral sensitivity in the ultraviolet region than crystalline systems, and output is greatly reduced when sealed with EVA containing a large amount of ultraviolet absorber. This is the reason why the output before the test in Comparative Example 3 is smaller than that in Example 4, indicating that the present invention also has the effect of minimizing the decrease in output due to sealing. In the case of an amorphous silicon solar cell, it is more remarkable.

  Furthermore, in Example 6, it was possible to prevent deterioration of the PET film as the back surface protection member due to ultraviolet rays by increasing the concentration of the UV absorber of the back surface sealing EVA. That is, it is not necessary to use a PVF film that is resistant to photodegradation as in the other examples, and a sufficiently reliable solar cell module can be produced even with an inexpensive member such as a PET film.

It is the schematic plan view and schematic sectional drawing of one Embodiment of the solar cell module which implemented this invention. It is a schematic sectional drawing showing the preparation process of a solar cell module. 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: PVF film (back surface protection member)
11: EVA sheet for front surface sealing 12: EVA sheet for rear surface sealing 13: Organic polymer resin

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 outside the solar cell element, the organic polymer resin includes a hindered amine light stabilizer, an organic peroxide a crosslinking agent consisting of are contained, the concentration of an organic compound contained in the organic polymer resin UV absorber Ri der 0.001 wt% or less, the non-light-receiving surface side of the solar cell element is organic high It is sealed with a molecular resin and a back surface protective member on the outside thereof, and the organic polymer resin on the non-light-receiving surface side contains a UV absorber at a higher concentration than the organic polymer resin on the light-receiving surface side. solar cell module, characterized in that there. 2. The solar cell module according to claim 1, wherein the concentration of the hindered amine light stabilizer contained in the organic polymer resin on the light receiving surface side is 0.5 to 1.0 wt%.

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