JP2015179826A - Cell crack prevention sheet for solar cell and solar cell module employing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cell crack prevention sheet for a solar cell module capable of applying a function for preventing a power generation element from being cracked even under an environment where a great bending stress is applied to the power generation element, when manufacturing, transporting or operating the solar cell module, and the solar cell module employing the same.SOLUTION: A cell crack prevention sheet 16 is structured by laminating a rubber composition layer 16B on a solar cell back sheet 16C, and the rubber composition layer 16B is laminated on the back sheet 16C in thickness equal to or more than 300 μm and made into a sheet. In the rubber composition layer 16B, an olefin rubber (B) is blended in 10 to 30 wt.% in an olefin rubber (A) in 100 wt.%, rubber hardness (JISA) of a rubber composition after thermoforming is 45 to 70, and rubber elongation is equal to or more than 100% and equal to or less than 500%.

Description

  The present invention relates to an olefin rubber layer capable of preventing cracking of solar cells, and more specifically, a sheet capable of preventing cracking due to distortion of solar cells due to the pressure of the solar cell module itself or external factors (snow, wood, etc.) The present invention relates to a solar cell module including a sheet.

  When operating a power generation business using solar cells, important business elements are capital investment and maintenance costs. In order to become an energy source similar to thermal power generation, these cost reductions are essential. More importantly, there is a need for solar cell modules that are free from power generation degradation for at least 40 years. Currently, there are many cases where power generation degradation is guaranteed less than 20% in 20 years, but in reality there are cases where it is not even more efficient, and periodic maintenance does not cause power generation degradation. It is necessary to make it.

  And when the environment where a solar cell module is used is considered, in order to receive more sunlight, it is installed in a mountain or a field, or is installed on the roof of a house or building. In such an environment, when a snow or a foreign object such as a tree branch is piled up on the solar cell module, the solar cell module is distorted. The battery module will be distorted.

  When the solar cell module is severely distorted, the solar cell module itself is eventually broken, or the solar cells constituting the solar cell module are broken, and the function of electrical conversion is lost. Since the solar cells included in the solar cell module are connected in series with each other, when any one of the solar cells breaks and normal electrical conversion cannot be performed, the solar cells are connected in series with the broken solar cells. All of the solar battery cells cannot perform electrical conversion.

  From this point of view, there is a demand for a technique that can prevent the solar battery module from cracking due to strain, and there is a patent document that discloses a sheet or film for protecting a solar battery cell.

  A resin composition for a solar cell encapsulant comprising an ethylene / α-olefin copolymer, an organic peroxide, and a silane coupling agent has been proposed (see, for example, Patent Document 1). This resin composition for solar cell encapsulating materials is said to be excellent in heat resistance, transparency, flexibility and adhesion to glass substrates. A solar cell comprising a copolymer obtained by copolymerizing an α-olefin copolymer and an ethylene-modified unsaturated silane compound as a comonomer, and an alkoxy group-containing silane coupling agent and / or an alkoxy group-containing silicone oligomer. A resin composition for a sealing material has been proposed (for example, Patent Document 2). This resin composition for solar cell encapsulant is said to be excellent in adhesiveness with a transparent front substrate, a back surface protective sheet, and a metal film.

  However, the conventional technology cannot prevent the solar cell from being cracked due to external factors such as snow and trees. Therefore, power generation deterioration of the solar cell module due to external factors cannot be prevented.

WO2010 / 114028 JP2011-187822

  The present invention provides a solar cell module capable of providing a function that does not crack the power generation element even in an environment where a large bending stress is applied to the power generation element during manufacture, transportation, and operation of the solar cell module that solves the above problems. A cell crack prevention sheet and a solar cell module using the same are provided.

<1> 1st invention The cell crack prevention sheet for solar cells of 1st invention for solving the said subject,
A cell crack prevention sheet in which a solar cell backsheet and an olefin rubber composition are integrated,
A rubber composition having a thickness of 300 μm or more is integrally formed on the back sheet. The rubber composition contains 10 to 30 parts by weight of the olefin resin (B) with respect to 100 parts by weight of the olefin rubber (A). The rubber composition after heat molding has a rubber hardness (JISA) of 45 to 70 and a rubber elongation of 100% to 500%.

  The cell crack prevention sheet of the present invention is a sheet of an olefin rubber composition in which 10 to 30 parts by weight of an olefin resin (B) is blended with 100 parts by weight of an olefin rubber (A) on a known back sheet (PET or the like). It is integrated into a shape. When the olefin-based resin (B) is less than 10 parts by weight, the rubber composition cannot be adhered to the solar battery cell at the time of layup of the solar battery member before lamination, so that the positioning according to the glass size cannot be performed, or the position There is a possibility that the time required for the combination becomes enormous and economical processing cannot be performed. If the amount exceeds 30 parts by weight, the rubber composition becomes too hard, and the effect of preventing cell cracking of the present invention may not be obtained.

  The olefin rubber composition thus obtained is provided in a sheet form on a known back sheet (PET or the like) at a thickness of 300 μm or more and integrated. When the thickness is less than 300 μm, the function of preventing the cracking of the solar battery cell is lowered, and there is a possibility that the solar battery cell in the solar battery module using the cell cracking sheet of the present invention may be cracked. Preferably they are 350 micrometers-800 micrometers, More preferably, they are 400 micrometers-600 micrometers. When the thickness is larger than 800 μm, the rubber layer contains bubbles generated by the crosslinking reaction, which is not preferable.

  By using the cell crack prevention sheet of the present invention as a back sheet on the opposite surface side of the solar cell module, foreign matter such as snow or wood is loaded on the solar cell module, and bending (distortion) is caused by the pressure of the solar cell module. Even if it occurs, it will not crack. Therefore, long-term power generation production of the solar cell module can be guaranteed.

<2> 2nd invention The solar cell module of the 2nd invention is a solar cell module using the photovoltaic cell crack prevention sheet of the 1st invention, Comprising: Each interface is formed by shape | molding at the temperature of 130 degreeC or more. It is characterized by being bonded. The molding temperature is preferably 140 ° C to 180 ° C, more preferably 145 ° C to 165 ° C. When the molding temperature is lower than 130 ° C., the adhesion between the back sheet and the rubber composition becomes weak, and the effect of preventing cell cracking cannot be obtained. If the temperature exceeds 180 ° C., the adhesive used in the back sheet is thermoset (thermally deteriorated) and the waterproof property is lowered, which is not preferable.

  Since the solar cell module of the present invention uses the cell crack prevention sheet of the first invention, it exhibits the same effect as the first invention.

Explanatory drawing of a structure of the cell crack prevention sheet of this invention. Explanatory drawing of the manufacturing method of the cell crack prevention sheet of this invention. Explanatory drawing of the embodiment of the solar cell module of this invention. Structure explanatory drawing of a photovoltaic cell. Structure explanatory drawing of the string which electrically connected two or more photovoltaic cells. Explanatory drawing of the implementation aspect of the solar cell module of Example 4 of this invention. Explanatory drawing of a structure of the conventional solar cell module. Schematic of the cell crack test. The state of the cell crack after the cell crack test of the solar cell module of an Example and the conventional solar cell module of the comparative example 4. FIG.

  Hereinafter, with reference to FIGS. 1-8, embodiment of the solar cell module using the cell crack prevention sheet of this invention and this cell crack prevention sheet is described.

  FIG. 1 is a configuration explanatory view of a cell crack preventing sheet in which an olefin rubber layer 16B of the present invention and a known back sheet 16C are integrated. Moreover, although the PET film for mold release may be affixed on the upper surface of the olefin rubber layer, it is preferable that it does not exist. Even if there is no PET film for release, it can be easily peeled off from the rolled sheet.

<1> Production of transparent olefin rubber material

<1-1> Ethylene / α-Olefin Copolymer The ethylene / α-olefin copolymer used in the cell crack prevention sheet for solar cell of the present embodiment is composed of ethylene and an α-olefin having 3 to 20 carbon atoms. Can be obtained by copolymerization. As the α-olefin, usually, an α-olefin having 3 to 20 carbon atoms can be used alone or in combination of two or more. Examples of the α-olefin having 3 to 20 carbon atoms include linear or branched α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3, Examples include 3-dimethyl-1-butene, 4-methyl-1-pentene, 1-octene, 1-decene, and 1-dodecene. Among these, α-olefins having 10 or less carbon atoms are preferable, and α-olefins having 3 to 8 carbon atoms are particularly preferable. Propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene and 1-octene are preferred because of their availability. The ethylene / α-olefin copolymer may be a random copolymer or a block copolymer, but a random copolymer is preferred from the viewpoint of flexibility.

  Furthermore, the ethylene / α-olefin copolymer used in the solar cell cell crack prevention sheet of the present embodiment is a copolymer composed of ethylene, an α-olefin having 3 to 20 carbon atoms, and a non-conjugated polyene. Also good. The α-olefin is the same as described above, and examples of the non-conjugated polyene include 5-ethylidene-2-norbornene (ENB), 5-vinyl-2-norbornene (VNB), and dicyclopentadiene (DCPD). These non-conjugated polyenes can be used alone or in combination of two or more.

<1-2> Olefin resin (B)
The polyolefin resin (B) used in the present invention is a thermoplastic resin, specifically,
Ethylene homopolymer such as high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE) or ethylene and 3 to 20 carbon atoms, preferably 3 carbon atoms Crystalline ethylene / α-olefin copolymer consisting of ˜8 α-olefin; propylene homopolymer. The melting point of these polyolefins is 130 ° C. or less. Among these, polyethylene is preferable, and polyethylene is particularly preferable.

<1-3> Silane coupling agent The cell crack prevention sheet for solar cells of this embodiment contains the silane coupling agent which has at least 1 type chosen from the group of a vinyl group, a methacryl group, and an acryl group.

  As the silane coupling agent, the silane coupling agent (A) having at least one selected from the group of vinyl group, methacryl group and acrylic group is an ethylene / α-olefin copolymer by a radical generated from an organic peroxide. The silane coupling agent (A) is graft-modified to exhibit adhesion to a surface protective member (glass or the like), solar cell element, metal film, metal electrode, solder, and back surface protective member. Content of the silane coupling agent (A) which has at least 1 type chosen from the group of the vinyl group in the solar cell sealing material of this embodiment, a methacryl group, and an acryl group is 100 weight of ethylene-alpha-olefin copolymers. The amount is preferably 0.1 to 5 parts by weight, more preferably 0.1 to 4 parts by weight, and particularly preferably 0.1 to 3 parts by weight with respect to parts.

  Adhesiveness improves that content of the silane coupling agent which has at least 1 type chosen from the group of a vinyl group, a methacryl group, and an acryl group is 0.1 weight part or more. A conventionally well-known thing can be used for a silane coupling agent, and there is no restriction | limiting in particular. Specifically, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris (β-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane 3-Methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-acryloxypropyltrimethoxysilane and the like can be used. Preferred examples include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, and vinyltriethoxysilane, which have good adhesion.

  The content of the epoxy group-containing silane coupling agent (B) in the solar cell cell crack preventing sheet of this embodiment is preferably 0.05 to 2 with respect to 100 parts by weight of the ethylene / α-olefin copolymer. 0.0 part by weight.

<1-4> Hindered amine light stabilizer It is preferable that the cell crack prevention sheet for solar cells of this embodiment further contains a hindered amine light stabilizer. By including a hindered amine light stabilizer, radicals harmful to the ethylene / α-olefin copolymer can be captured, and generation of new radicals can be suppressed. Examples of hindered amine light stabilizers include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and 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 }] And the like, hindered piperidine compounds, and the like can be used.

  The content of the hindered amine light stabilizer in the solar cell encapsulant of this embodiment is preferably 0.01 to 2.0 parts by weight with respect to 100 parts by weight of the above-mentioned ethylene / α-olefin copolymer. Yes, more preferably 0.01 to 1.6 parts by weight.

<1-5> Hindered phenol stabilizer It is preferable that the solar cell sealing material of this embodiment further contains a hindered phenol stabilizer. By including a hindered phenol-based stabilizer, harmful radical species can be captured in the ethylene / α-olefin copolymer in the presence of oxygen, generation of new radicals can be suppressed, and oxidative degradation can be prevented. As the hindered phenol stabilizer, a conventionally known compound can be used. For example, 1,1,3-tris- (2-methyl-4-hydroxy-5-tert-butylphenylbutane, 4,4 ′ -Butylidenebis- (3-methyl-6-tert-butylphenol), 2,2-thiobis (4-methyl-6-tert-butylphenol), 7-octadecyl-3- (4'-hydroxy-3 ', 5'- Di-t-butylphenyl) propionate, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate methane, pentaerythritol-tetrakis [3- (3 5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyl) Nyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,4-bis (n-octylthio) -6- (4 -Hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate, 2,2-thio- Diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy) -hydrocinna Amido, 2,4-bis [(octylthio) methyl] -o-cresol, 3,5-di-t-butyl-4-hydroxybenzyl-phosphonate-diethyl ester, tetrakis [me Tylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)] Methane, octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) proonate, 3,9- Bis [2- {3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4-8,10-tetraoxaspiro [5 5] Undecane, etc. Among others, pentaerythritol-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-, among others, can be mentioned. t-Butyl-4-hydroxyphenyl) proonate is preferred.

  The content of the hindered phenol-based stabilizer in the solar cell prevention sheet of this embodiment is preferably 0.005 to 0.1 parts by weight with respect to 100 parts by weight of the ethylene / α-olefin copolymer. More preferably 0.01 to 0.1 parts by weight, particularly preferably 0.01 to 0.06 parts by weight. When the content of the hindered phenol stabilizer is 0.005 parts by weight or more, the heat resistance is good. It tends to be suppressed. When the content of the hindered phenol stabilizer is 0.1 parts by weight or less, the crosslinking property of the solar cell encapsulant is good, and the heat resistance and adhesiveness are good. In addition, under high temperature and high humidity, when used in combination with a basic hindered amine light stabilizer, the hydroxyl group of the hindered phenol stabilizer forms a salt, forming a conjugated bisquinone methide compound that is quinonelated and dimerized, and is sealed with solar cells. Although it tends to cause yellowing of the material, yellowing of the solar cell encapsulating material can be suppressed when the hindered phenol-based stabilizer is 0.1 parts by weight or less.

<1-6> Phosphorus stabilizer It is preferable that the solar cell sealing material of this embodiment further contains a phosphorus stabilizer. When the phosphorus-based stabilizer is contained, the generated radical can be eliminated and a sheet having a good appearance can be produced.

  As the phosphorus stabilizer, a conventionally known compound can be used, for example, tris (2,4-di-tert-butylphenyl) phosphite, bis [2,4-bis (1,1-dimethylethyl) -6-methylphenyl] ethyl ester phosphorous acid, tetrakis (2,4-di-tert-butylphenyl) [1,1-biphenyl] -4,4'-diylbisphosphonite, and bis (2,4 -Di-tert-butylphenyl) pentaerythritol diphosphite and the like. Among these, tris (2,4-di-tert-butylphenyl) phosphite is preferable.

  The content of the phosphorus stabilizer in the solar cell encapsulant of the present embodiment is preferably 0.005 to 0.5 parts by weight with respect to 100 parts by weight of the ethylene / α-olefin copolymer.

<1-7> Ultraviolet Absorber The solar cell sealing material of the present embodiment preferably further includes an ultraviolet absorber. It is preferable that content of the ultraviolet absorber in the solar cell sealing material of this embodiment is 0.005 to 5 parts by weight with respect to 10 parts by weight of the ethylene / α-olefin copolymer. It is preferable for the content of the ultraviolet absorber to be in the above-mentioned range since the balance between weather resistance stability and crosslinking properties is excellent. Specific examples of the ultraviolet absorber include 2-hydroxy-4-normal-octyloxybenzophenone, 2-hydroxy-4methoxybenzophenone, 2,2-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy- Benzophenones such as 4-carboxybenzophenone and 2-hydroxy-4-N-octoxybenzophenone; 2- (2-hydroxy-3,5-di-t-butylphenyl) benzotriazole, 2- (2-hydroxy-5 -Methylphenyl) benzotriazol-based compounds such as benzotriazole; salicylic acid ester-based compounds such as phenylsalicylate and p-octylphenylsalicylate are used.

<1-8> Other additives Various resins other than polyolefins and / or various rubbers, plasticizers, fillers, pigments, dyes, antistatic agents, antibacterial agents, antifungal agents, flame retardants, crosslinking aids, hinders One or more additives selected from other heat-resistant stabilizers other than dophenol-based stabilizers and phosphorus-based stabilizers, dispersants, and the like can be appropriately contained.

  As other heat stabilizers other than the hindered phenol stabilizer and the phosphorus stabilizer, specifically, 3-hydroxy-5,7-di-tert-butyl-furan-2-one, o-xylene, Lactone-based heat stabilizers such as reaction products of dimyristylthiodipropionate, dilaurylthiodipropionate, distearylthiodipropionate, ditridecylthiodipropionate, pentaerythritol-tetrakis- (β-lauryl- Thiopropionate), 2-mercaptobenzimidazole, zinc salt of 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, zinc salt of 2-mercaptomethylbenzimidazole, 4,4′thiobis (6-t-butyl- 3-methylphenol), 2,6-di-t-butyl-4- Sulfur-based heat stabilizers such as (4,6-bis (octylthio) -1,3,5-triazin-2-ylamino) phenol; amine-based heat stabilizers.

  In particular, when a crosslinking aid is contained, the content of the crosslinking aid in the solar cell encapsulant of the present embodiment is preferably 0.05 with respect to 100 parts by weight of the ethylene / α-olefin copolymer. -5 parts by weight, more preferably 0.1-3 parts by weight. It is preferable for the content of the crosslinking aid to be in the above-mentioned range since an appropriate crosslinked structure can be obtained, and heat resistance, mechanical properties and adhesiveness can be improved.

  As the crosslinking aid, conventionally known ones generally used for olefin rubbers can be used. Such a crosslinking aid is a compound having two or more double bonds in the molecule. Specifically, monoacrylates such as t-butyl acrylate, lauryl acrylate, cetyl acrylate, stearyl acrylate, 2-methoxyethyl acrylate, ethyl carbitol acrylate, methoxytripropylene glycol acrylate; t-butyl methacrylate, lauryl methacrylate, cetyl methacrylate Monomethacrylate such as stearyl methacrylate, methoxyethylene glycol methacrylate, methoxypolyethylene glycol methacrylate; 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, neopentyl glycol diacrylate , Diethylene glycol diacrylate, tetraethylene glycol diacrylate Diacrylate, polyethylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, etc .; 1,3-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate neo Dimethacrylates such as pentyl glycol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate; triacrylates such as trimethylolpropane triacrylate, tetramethylolmethane triacrylate, pentaerythritol triacrylate; Trimethylolpropane trimethacrylate Trimethacrylates such as methylolethane trimethacrylate; Tetraacrylates such as pentaerythritol tetraacrylate and tetramethylolmethane tetraacrylate; Divinyl aromatic compounds such as divinylbenzene and di-i-propenylbenzene; Triallyl cyanurate and triallyl isocyanurate A diallyl compound such as diallyl phthalate; a triallyl compound; an oxime such as p-quinonedioxime and pp′-dibenzoylquinonedioxime; and a maleimide such as phenylmaleimide.

  Of these crosslinking aids, more preferred are triacrylates such as diacrylate, dimethacrylate, divinyl aromatic compound, trimethylolpropane triacrylate, tetramethylolmethane triacrylate, pentaerythritol triacrylate; trimethylolpropane trimethacrylate , Trimethacrylates such as trimethylolethane trimethacrylate; tetraacrylates such as pentaerythritol tetraacrylate and tetramethylolmethane tetraacrylate; cyanurates such as triallyl cyanurate and triallyl isocyanurate; diallyl compounds such as diallyl phthalate; triallyl compounds: p -Oximes such as quinonedioxime and pp'-dibenzoylquinonedioxime; phenylmale Maleimide such as imide: Further, among these, triallyl isocyanurate is particularly preferable, and the balance between the generation of bubbles and the crosslinking property of the solar cell sealing material after lamination is most excellent.

  The cell crack prevention sheet for solar cells of this embodiment has an organic peroxide content of 0.1 to 3 parts by weight with respect to 100 parts by weight of the above-mentioned ethylene / α-olefin copolymer, and is hindered. The phenol stabilizer content is 0.05 to 0.1 parts by weight, the hindered amine light stabilizer content is 0.01 to 2.0 parts by weight, and the phosphorus stabilizer content is 0. It is a preferable embodiment that the resin composition is 0.05 to 0.5 part by weight.

  Furthermore, the cell crack prevention sheet for solar cells of the present embodiment has an organic peroxide content of 0.5 to 3.0 parts by weight with respect to 100 parts by weight of the ethylene / α-olefin copolymer described above. Yes, the content of the hindered phenol stabilizer is 0.01 to 0.06 parts by weight, the content of the hindered amine light stabilizer is 0.05 to 1.6 parts by weight, It is a particularly preferable embodiment that the resin composition has a content of 0.02 to 0.2 parts by weight.

<2> Cell crack prevention sheet It is preferable to use a kneader or a Banbury mixer for preparing the rubber material, and the solar cell encapsulant of this embodiment may be produced by melt blending with an extruder or the like. Is possible. The cell crack prevention sheet for solar cells of the present embodiment is formed by laminating and integrating an olefin rubber layer and a known back sheet, and the overall shape is a sheet shape. By integrating with a known back sheet, long-term reliability as a solar cell member can be obtained. Since it cannot be laid up separately during processing, it is essential that the cell crack prevention sheet is an integral part of the rubber composition and the back sheet.

  There are no particular restrictions on the method for forming the cell crack prevention sheet for solar cells, but various known molding methods (cast molding, extrusion sheet molding, inflation molding, injection molding, compression molding, calendar molding, etc.) should be adopted. Can do. Hereinafter, molding of the cell crack preventing sheet of the present invention will be described by a calendar molding method.

  The manufacturing method will be described with reference to FIG. In this figure, the sealing sheet of this invention is obtained by the calendering method. A predetermined gap is set between the roll 1 and the roll 2 adjusted to an appropriate temperature, and the olefin rubber material obtained by kneading between the rolls is placed in the gap between the roll 1 and the roll 2 to obtain the olefin rubber material layer 16B. be able to. The transparent olefin rubber material layer 16 </ b> B formed to have a constant thickness moves on the roll 3.

  The cell crack preventing sheet 16 of the present invention may be composed of only the layer made of the cell crack preventing sheet 16 of the present embodiment, or a layer other than the layer containing the cell crack preventing sheet (hereinafter referred to as “other layers”). May also be included). Examples of other layers include a hard coat layer, an adhesive layer, an antireflection layer, a gas barrier layer, and an antifouling layer for protecting the front or back surface, if classified for purposes. If classified according to the material, a layer made of an ultraviolet curable resin, a layer made of a thermosetting resin, a layer made of a polyolefin resin, a layer made of a carboxylic acid-modified polyolefin resin, a layer made of a fluorine-containing resin, a cyclic olefin copolymer And a layer made of an inorganic compound.

<3> Solar cell module A solar cell module is a crystal in which, for example, a solar cell element usually formed of crystalline silicon is sandwiched between solar cell sealing material sheets, and both front and back surfaces are covered with a protective sheet. Type solar cell module. That is, a typical solar cell module includes a solar cell module protective sheet (front surface side transparent protective member) / solar cell encapsulant / solar cell element / solar cell encapsulant / solar cell module protective sheet (back side protection). Member). However, the solar cell module which is one of the preferred embodiments of the present embodiment is not limited to the above-described configuration, and a part of each of the above layers is appropriately omitted as long as the object of the present invention is not impaired. Layers other than the above can be provided as appropriate. Examples of the layer other than the above include an adhesive layer, a shock absorbing layer, a coating layer, an antireflection layer, a back surface rereflection layer, and a light diffusion layer. These layers are not particularly limited, but can be provided at appropriate positions in consideration of the purpose and characteristics of each layer.

<3-1> Crystalline Silicon Solar Cell Module FIG. 3 is a cross-sectional view schematically showing one embodiment of the solar cell module of the present invention. FIG. 3 shows an example of the configuration of the crystalline silicon solar cell module 100. As shown in FIGS. 4 and 5, the solar cell module 100 includes a plurality of crystalline silicon-based solar cell elements (solar cell) 15 electrically connected by an interconnector 19 and a pair of sandwiching them. It has a front surface side transparent protective member (hereinafter referred to as “transparent substrate”) 11 and a back surface side protective member (hereinafter referred to as “back surface material”) 16, and existing existing between a plurality of solar cell elements 15 and the transparent substrate. A sealing sheet (such as EVA) 18 is stacked and filled. Further, the back surface side protection member 16 is a cell crack prevention sheet of the present invention, and has a configuration in which an olefin rubber material layer 16B is disposed on and integrated with a polyethylene retephthalate (PET) material 16C. This back material 16 can be manufactured by the method for producing a cell crack prevention sheet described in <2>. The transparent base 11, the existing sealing sheet 18, the solar battery cell 15, and the back material 16 are laminated from the bottom in this order and obtained by thermocompression bonding (laminating). The light receiving surface 15 </ b> A of the solar battery cell 15 is in contact with the existing sealing sheet 18 and sealed. The back surface 15B of the solar battery cell is sealed in contact with the olefin rubber material layer 16B of the cell crack prevention sheet 16 of the present invention.

  FIG. 4 is a plan view schematically showing a configuration example of the light receiving surface and the back surface of the solar battery cell 15. In FIG. 4, an example of the configuration of the light receiving surface 15A and the back surface 15B of the solar battery cell 15 is shown. As shown in FIG. 4 (a), the light receiving surface 15A of the solar battery cell 15 collects electric charges from the current collectors (fingers) 151 formed in a line shape and the current collector 151, and the interconnector 19 And a bus bar with tabs (bus bar) 152 connected to each other. Further, as shown in FIG. 4B, a conductive layer (back electrode) 153 is formed on the entire back surface 15B of the solar battery cell 15, and charges are collected from the conductive layer 153 on the conductive layer 153. A tabbed bus (bus bar) 154 connected to the connector 19 is formed. The line width of the collector 151 is, for example, about 0.1 mm, the line width of the tabbed bus 152 is, for example, about 2-3 mm, and the line width of the tabbed bus 154 is, for example, about 5-7 mm. is there. The thicknesses of the current collector 151, the tabbed bus 152, and the tabbed bus 154 are, for example, about 20 to 50 μm. A plurality of solar cells 15 are connected by an interconnector 19 to form a string W shown in FIG. A plurality of rows of the strings W are connected by electrode materials and supplied as solar cells 15 of the solar cell module.

  The current collector 151, the tabbed bus 152, and the tabbed bus 154 preferably include a metal having high conductivity. Examples of such highly conductive metals include gold, silver, copper, and the like. From the viewpoint of high conductivity and high corrosion resistance, silver, silver compounds, alloys containing silver, and the like are preferable. The conductive layer 153 contains not only a highly conductive metal but also a highly light reflective component such as aluminum from the viewpoint of improving the photoelectric conversion efficiency of the solar cell element by reflecting light received by the light receiving surface. It is preferable. The current collector 151, the tab-attached bus 152, the tab-attached bus 154, and the conductive layer 153 are made of, for example, a screen containing a conductive material paint containing the above highly conductive metal on the light-receiving surface 15A or the back surface 15B of the solar battery cell 22. It is formed by applying to a coating thickness of 50 μm by printing, drying, and baking at, for example, 600 to 700 ° C. as necessary. If these conventional sealing sheets (EVA etc.) are used for these electrodes, acetic acid will generate | occur | produce during use and will corrode an electrode. As shown in FIG. 6, such electrode corrosion can be prevented by using the transparent olefin rubber layer 16D used in the cell crack prevention sheet of the present invention as a sealing sheet. In addition, as shown in FIG. 6, when a cover glass is used as the transparent substrate 11 by sandwiching the cyclic olefin copolymer sheet 14 between the transparent olefin rubber layers 16D used in the cell crack prevention sheet of the present invention. It is possible to prevent metal ions such as sodium ions in the cover glass from being deposited on the solar battery cell and to eliminate the occurrence of PID.

  Since the surface side transparent protective member (transparent substrate) 11 is arranged on the light receiving surface side, it needs to be transparent. Examples of the transparent substrate 11 include a transparent glass plate and a transparent resin film. On the other hand, the back surface side protection member (back surface material) 16 is the cell crack prevention sheet of the present invention, and does not need to be transparent. The material of the back sheet which is a constituent member of the cell crack prevention sheet is not particularly limited.

<5> Manufacturing Method of Solar Cell Module The solar cell module 100 can be obtained by any manufacturing method. The solar cell module 100 is obtained by a manufacturing method including the following steps, for example. The cell crack prevention sheet 16 (including the olefin rubber material layer 16B and a known back sheet material) corresponding to the back material of the present invention, a plurality of solar cells 15, the existing sealing sheet 18, and the transparent substrate 11 are arranged in this order. A step of obtaining a laminated body; a step of pressurizing and laminating the laminated body with a laminating apparatus or the like, and simultaneously heating as necessary; after the above step, the laminated body is further heat-treated as necessary, and the sealing It is a manufacturing method provided with the process of hardening material.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples.

[Example 1]
To 100 parts by weight of 80 parts by weight of EPT4021 manufactured by Mitsui Chemicals and 20 parts by weight of EPT4045 manufactured by Mitsui Chemicals, 25 parts by weight of low density polyethylene manufactured by Mitsui Chemicals is added as an olefin resin. 45 parts by weight of process oil PW-380, 0.5 parts by weight of stearic acid, 20 parts by weight of talc, 0.5 parts by weight of 3-methacryloxypropyltrimethoxysilane as a silane coupling agent, as a crosslinking aid 1.2 parts by weight of triallyl isocyanurate, 0.4 parts by weight of 2-hydroxy-4-normal-octyloxybenzophenone as an ultraviolet absorber, bis (2,2,6,6-tetra as a hindered amine light stabilizer 0.2 parts by weight of methyl-4-piperidyl) sebacate, tris (2.4-diphosphorus) 0.1 parts by weight tert- butylphenyl) phosphite, to give a kneaded rubber composition at 80 ° C. 7.0 parts by weight, manufactured by Arkema Luperox 101XL as organic peroxide at 18 inches roll.

  Next, an olefin rubber layer having a predetermined thickness of 300 μm was laminated on a PET back sheet manufactured by Toyo Aluminum Co., Ltd. by calendar molding according to FIG. The calender rolls 1 and 2 were molded at a temperature of 80 ° C, the roll 3 at 60 ° C, and the roll 7 at 40 ° C.

  Using the obtained cell crack prevention sheet, a solar cell module 100 having a length of 48 was obtained by the manufacturing method described in <5> for the solar cell module having the configuration shown in FIG. The laminating method used was a Nisshinbo laminating apparatus PVL1537N, vacuuming was performed for 4 minutes, pressure holding time was 30 minutes, and molding temperature was 148 ° C. In addition, RC02 (450 micrometers) which is EVA made from Mitsui Chemicals was used as an existing adhesive sheet.

[Example 2]
A cell crack prevention sheet 16 was prepared in the same manner as in Example 1 except that the olefin resin was 15 parts by weight, the talc was 30 parts by weight, and the thickness of the olefin rubber material layer was 350 μm. Obtained.

[Example 3]
The cell crack prevention sheet 16 was prepared in the same manner as in Example 1 except that 30 parts by weight of the olefin resin, 45 parts by weight of talc, and the thickness of the olefin rubber material layer were 400 μm. Obtained.

[Example 4]
A cell crack preventing sheet 16 was prepared in the same manner as in Example 1 except that 20 parts by weight of the olefin resin, 45 parts by weight of talc, and the thickness of the olefin rubber material layer were 500 μm. In this example, the sealing sheet on the light-receiving surface side is one having a structure in which a cyclic olefin copolymer sheet (PID countermeasure film) 14 is sandwiched between transparent olefin rubber material layers 16D. A battery module 200 was obtained.

[Comparative Example 1]
A cell crack prevention sheet 16 was prepared in the same manner as in Example 1 except that the olefin resin was 20 parts by weight, talc was 100 parts by weight, and the thickness of the olefin rubber material layer was 450 μm. Obtained.

[Comparative Example 2]
A cell crack prevention sheet 16 was prepared in the same manner as in Example 1 except that 5 parts by weight of the olefin resin, 50 parts by weight of talc, and the thickness of the olefin rubber material layer was 200 μm. Obtained.

[Comparative Example 3]
A cell crack prevention sheet 16 was prepared in the same manner as in Example 1 except that the olefin resin was 0 part by weight, talc was 20 parts by weight, and the thickness of the olefin rubber material layer was 150 μm. Obtained.

[Comparative Example 4]
This comparative example is the conventional commercially available solar cell module 900 of FIG. The back sheet 12 is a conventional PET film. The sealing material 18 is an existing EVA film and is the same as that of the first embodiment.

[Comparative Example 5]
A cell crack prevention sheet 16 was prepared in the same manner as in Example 1 except that 30 parts by weight of the olefin resin, 45 parts by weight of talc, and the thickness of the olefin rubber material layer were 500 μm. Obtained.

[Handling property of cell crack preventing sheet of the present invention]
When the solar cell module of the cell crack prevention sheet prepared in Example 1 to Example 4 and Comparative Example 1 to Comparative Example 4 is manufactured (laid up) as a member, the cell crack prevention sheet of the present invention is used. -It was evaluated according to the following evaluation indexes whether the positioning of the G could be easily performed. The evaluation results are shown in Table 1.
<Handling>
Evaluation point 3 points: The cell-breaking sheet and the solar battery cell do not adhere to each other, and the positioning of the cell-breaking sheet is easy.
Evaluation point 2 points: Intermediate state between 3 evaluation points and 2 evaluation points.
Evaluation point 1 point: The cell crack sheet adheres to the solar battery cell, and the cell crack sheet cannot be positioned.

[Cell cracking test]
FIG. 8 shows the cracked state of the cells in the solar cell module when a pressure of 5400 Pa was applied to the solar cell modules of Example 1 to Example 4 and Comparative Example 1 to Comparative Example 5 with a pressure tester manufactured by Honda Kogyo. The solar cell module was set in the dark room, a forward current was passed through the cell, the light emission state was photographed with an EL camera, and the cell cracking state was judged. The evaluation results are shown in Table 1.
<Presence of cracks>
Evaluation point 5 points: In the cell cracking test, the number of cells in which cell cracking is recognized is zero at a pressure of 5400 Pa.
Evaluation point 4 points: In the cell cracking test, the number of cells in which cell cracking is observed is 4 or less at a pressure of 5400 Pa.
Evaluation point 3 points: In the cell cracking test, the number of cells in which cell cracking is observed is 8 or less at a pressure of 5400 Pa.
Evaluation point 2 points: In the cell cracking test, it means that the number of cells in which cell cracking is observed is 16 or less at a pressure of 5400 Pa.
Evaluation point 1 point: In a cell cracking test, it means that the number of cells in which cell cracking is observed is 24 or less at a pressure of 5400 Pa.

[Power generation performance check]
After performing a cell cracking test on the solar cell modules produced in Examples 1 to 4 and Comparative Examples 1 to 4, the power generation performance was confirmed as follows. The results are shown in Table 1.

  The output of the solar cell module prepared in advance was measured with a solar simulator manufactured by Nisshinbo. Using a solar cell module that has been cell-cracked at a pressure of 5400 Pa in a cell-cracking test, after a dump heat test (85 ° C., 85 RH%, 3000 hours) in a constant temperature and humidity chamber manufactured by Espec, the output is again made by Nisshinbo Co., Ltd. Measured with a solar simulator. Table 1 shows the initial output value before the test of the solar cell module and the output measurement value after the cell crack test.

  Table 1 shows the results of various evaluation tests of the solar cell modules produced in Example 1 to Example 4 and Comparative Example 1 to Comparative Example 4. From these results, the solar cell modules of Example 1 to Example 4 have no cell cracking and no change in output after the cell cracking test. The state of cell cracking of the solar cell module of Example 1 and the conventional solar cell module of Comparative Example 5 is shown as a captured image of an EL image by the test apparatus of FIG. 9A is an EL photographed image of the module of Example 1, and FIG. 9B is an EL photographed image of the module of Comparative Example 4. Looking at both the captured images, the cells in the module of Example 1 using the cell crack prevention sheet of the present invention have no cell cracks. On the other hand, it can be seen that the conventional module of Comparative Example 4 has many cracks in the cell. In addition, there is no problem in handling at the time of laying up the cell crack prevention sheet of the present invention when manufacturing a solar cell module.

  On the other hand, in the solar cell module of the comparative example, 16 or more cell cracks occurred in the cell crack test, and the output of the solar cell was reduced.

  According to the present invention, since the cell crack prevention sheet is used even when pressure acting as a load is applied to the solar cell module due to external factors such as snow accumulation while using the solar cell module, the olefin rubber material layer is It becomes a cushion and cell cracking can be prevented. Therefore, power can be stably generated without a decrease in output over a long period of use.

DESCRIPTION OF SYMBOLS 100 Solar cell module 200 Solar cell module 11 Cover glass (transparent body)
14 PID countermeasure film 15 Solar cell element (solar cell)
16 Cell crack prevention sheet 16B Olefin rubber material layer 16C Back surface material (known back sheet)
16D transparent olefin rubber layer 18 Conventional sealing sheet (EVA)
15A Light-receiving surface 15B Back surface 28 Sealing layer 19 Interconnector 151 Current collector 152 Bus bar with tab 153 Back electrode layer 154 Bus bar with tab

Claims (2)

A cell crack prevention sheet in which a solar cell backsheet and an olefin rubber composition are integrated,
A rubber composition having a thickness of 300 μm or more is integrally formed on the back sheet. The rubber composition contains 10 to 30 parts by weight of the olefin resin (B) with respect to 100 parts by weight of the olefin rubber (A). A cell crack prevention sheet, wherein the rubber composition after heat molding has a rubber hardness (JISA) of 45 to 70 and a rubber elongation of 100% to 500%.   It is a solar cell module using the solar cell crack prevention sheet of Claim 1, Comprising: Each interface is adhere | attached by shape | molding at the temperature of 130 degreeC or more. .