JP5655314B2 - Solar cell module - Google Patents

Description

The present invention relates to a solar cell module including a solar cell back surface protective sheet that has a function of reflecting near infrared rays while exhibiting substantially the same color as a solar cell element to human eyes.
Specifically, the solar cell back surface protective sheet used in the solar cell module of the present invention has the following characteristics. That is, among the layers constituting the solar cell back surface protective sheet, the adhesive layer closest to the sealant layer that seals the back surface of the solar cell element contains perylene black, and is not suitable for human eyes. Although it appears to be black with the same color as the battery element, it does not absorb near-infrared light and transmits it. And the other layer which comprises a solar cell back surface protection sheet reflects the transmitted near infrared rays.
Since the solar cell element can use the near infrared ray reflected by the solar cell back surface protective sheet for power generation, the energy conversion efficiency can be improved.
Furthermore, since the solar cell back surface protection sheet surface reflects near-infrared rays, heat storage of the solar cell back surface protection sheet itself can be suppressed, and the solar cell element can be suppressed from becoming high temperature, and as a result, a decrease in energy conversion efficiency can be suppressed.

In recent years, solar cells have been attracting attention as a clean energy source free from environmental pollution due to an increase in awareness of environmental problems, and earnestly researched and put into practical use from the viewpoint of using solar energy as a useful energy resource.
There are various types of solar cell elements, and typical examples thereof include a crystalline silicon solar cell element, a polycrystalline silicon solar cell element, an amorphous silicon solar cell element, a copper indium selenide solar cell element, and a compound semiconductor solar. Battery elements and the like are known. Among these, thin-film crystal solar cell elements, amorphous silicon solar cell elements, and compound semiconductor solar cell elements are relatively low cost and can be increased in area, and therefore are actively researched and developed in various fields. ing. Among these solar cell elements, thin film solar cell elements represented by amorphous silicon solar cell elements in which silicon is laminated on a conductive metal substrate and a transparent conductive layer is further formed thereon are lightweight, Since it is rich in impact resistance and flexibility, it is considered promising as a future form of solar cells.

  A simple one of the solar cell modules has a configuration in which a filler and a glass plate are sequentially laminated on both sides of the solar cell element. Since a glass plate is excellent in transparency, weather resistance, and scratch resistance, it is still generally used as a sealing sheet on the solar light receiving surface side. However, on the non-light-receiving surface side that does not require transparency, a back surface protection sheet for solar cells (hereinafter referred to as a back surface protection sheet) other than the glass plate has been developed by each company in terms of cost, safety, and workability. Is being replaced.

As the back surface protection sheet, a monolayer film such as a polyester film, a polyester film provided with a metal oxide or non-metal oxide vapor deposition layer, a polyester film, a fluorine-based film, an olefin film, an aluminum foil, etc. The multilayer film which laminated | stacked the film is mentioned.
The back surface protective sheet having a multilayer structure can impart various performances depending on the multilayer structure. For example, insulating properties can be imparted by using a polyester film, weather resistance can be imparted by using a fluorine-based film, and water vapor barrier properties can be imparted by using an aluminum foil.
What kind of back surface protection sheet is used can be appropriately selected depending on the product and application in which the solar cell module is used.

The appearance of the solar cell element is often black. Therefore, when the solar cell module is installed, it is desirable that the light receiving surface side of the back surface protection sheet is black in order not to impair the outdoor appearance.
Generally, carbon black is used as a black pigment because it has high coloring power and is inexpensive, but carbon black absorbs not only in the visible light region but also in the near infrared region. There exists a problem that it becomes easy to become high temperature and, as a result, the whole solar cell module tends to become high temperature. Since a solar cell element generally tends to have a lower output as the temperature rises, it is not desirable for the solar cell module to have a higher temperature.

The wavelength region absorbed by the solar cell differs depending on the solar cell element. The amorphous silicon solar cell element has absorption sensitivity at 300 to 800 nm, and the crystalline silicon solar cell element has absorption sensitivity at 400 to 1200 nm. When the light-receiving surface side of the back surface protection sheet is white, the solar cell element cannot absorb and the transmitted light is reflected by the back surface protection sheet and can enter the solar cell element, so that the photoelectric conversion efficiency is improved.
However, if the light-receiving surface side of the back surface protection sheet is made black using carbon black, all light from the visible region to the near infrared region is absorbed, and thus the transmitted light cannot be reused.

JP 2004-174469 A JP 2005-132461 A

  An object of the present invention is to use a black pigment that transmits near-infrared rays, so that the appearance is almost the same as that of a solar cell element and the appearance is not impaired. It is to provide a solar cell module comprising a solar cell back surface protective sheet that is provided with a function of increasing the energy conversion efficiency of the solar cell by providing a heat shielding function.

The present invention provides a solar cell surface sealing sheet (I) positioned on the light receiving surface side of a solar cell, a sealing material layer (II) positioned on the light receiving surface side of the solar cell, solar cells (III), and solar cell A solar cell module comprising a sealing agent layer (IV) positioned on the non-light-receiving surface side and a solar cell back surface protection sheet (V) in contact with the non-light-receiving surface side sealing agent layer (IV). And
The solar cell back surface protection sheet (V)
A black adhesive layer (1) provided by a coating method on the surface of a film (2) having an infrared reflectance of 700 to 1200 nm of 60 to 100%, containing a perylene black pigment, and having a thickness of 0. 1 to 10 μm carrying a black adhesive layer (1),
The black adhesive layer (1) is in contact with the non-light-receiving surface side sealant layer (IV),
The present invention relates to a solar cell module.
The non-light-receiving surface side sealing agent layer (IV) is preferably an ethylene-vinyl acetate copolymer filler layer.

As for the black adhesive layer (1) which comprises the said back surface protection sheet for solar cells (V), a film (2) comprises the white film (2-1) containing a white pigment, or a transparent film (2 -2) It is preferable to comprise -a and a white adhesive layer or a white coating layer (2-2) -b.
The white film (2-1) or the transparent film (2-2) -a is preferably a polyester film, and the white film (2-1) is preferably a foamed polyester film.

  Moreover, it is preferable that the white film (2-1) and the black adhesive layer (1) are in direct contact, and the other side of the white film (2-1) in which the black adhesive layer (1) is not in contact. Furthermore, at least one of a metal foil or a vapor deposition layer of a metal oxide or a nonmetal inorganic oxide can be further provided.

  In the back surface protection sheet (V) for solar cells, it is preferable to contain 0.5 to 20% by weight of perylene black pigment in 100% by weight of the black adhesive layer (1). Moreover, it is preferable to contain 1-10 weight% of perylene black pigments per 1 micrometer of thickness of a black adhesive layer (1).

  In the solar cell back surface protective sheet (V), the black adhesive layer (1) is preferably formed from an adhesive containing a hydroxyl group-containing resin (B) and a polyisocyanate compound (C). Furthermore, the resin (B) having a hydroxyl group is preferably a polyester resin (B1), and the glass transition temperature of the polyester resin (B1) is preferably 20 to 100 ° C.

  Furthermore, in the solar cell module of the present invention, the non-light-receiving surface side sealing agent layer (IV) is preferably an ethylene-vinyl acetate copolymer filler layer.

,
The solar cell module of the present invention has almost the same color as the solar cell element and does not impair the appearance. The solar cell module of the present invention has an effect of increasing the energy conversion efficiency of the solar cell by reflecting the near-infrared light transmitted without being absorbed by the solar cell element and effectively using the reflected near-infrared light for power generation. Furthermore, the near-infrared rays that are transmitted without being absorbed by the solar cell element are reflected to prevent the solar cell back surface protection sheet from becoming high temperature, thereby suppressing a decrease in energy conversion efficiency of the solar cell element.

It is a figure which shows typically the cross section of the module for solar cells of this invention. It is a figure which shows typically the cross section of the solar cell back surface protection sheet (V) of the 1st aspect used for the module for solar cells of this invention. It is a figure which shows typically the cross section of the solar cell back surface protection sheet (V) of the 2nd aspect used for the module for solar cells of this invention. It is a figure which shows typically the cross section of the solar cell back surface protection sheet (V) of the 3rd aspect used for the module for solar cells of this invention. It is a figure which shows typically the cross section of the solar cell back surface protection sheet (V) of the 4th aspect used for the module for solar cells of this invention.

  As shown in FIG. 1, the solar cell module of the present invention includes a solar cell surface sealing sheet (I) positioned on the light receiving surface side of the solar cell, and a sealing material layer (II) positioned on the light receiving surface side of the solar cell. ), Solar battery cell (III), sealant layer (IV) located on the non-light-receiving surface side of the solar battery, and solar battery back surface protection sheet (IV) in contact with the non-light-receiving surface side sealant layer (IV) V) a solar cell module comprising the solar cell back surface protective sheet (V) having a function of reflecting the perylene black-containing black adhesive layer (1) and near infrared rays; The black adhesive layer (1) and the sealant layer (IV) located on the non-light-receiving surface side are arranged so as to be in contact with each other.

  The solar cell surface sealing sheet (I) used in the present invention is located on the light receiving surface side of the solar cell, and can be efficiently absorbed by the solar cell element without losing the energy of sunlight. What is necessary is just to have a high gas barrier property which has high transparency and prevents the invasion of water vapor and oxygen which cause deterioration of the solar cell element. Specifically, a glass plate, a fluorine film and an inorganic oxide are deposited. Examples include a laminate of heat-resistant plastic films.

  The light-receiving surface side sealing material layer (II) and the non-light-receiving surface side sealing material layer (IV) used in the present invention sandwich the entire solar cell element (III) from both the light-receiving surface and the non-light-receiving surface. . As the light-receiving surface side sealing material layer (II) and the non-light-receiving surface side sealing material layer (IV), a thermoplastic olefin resin, a thermoplastic urethane resin, an acetal resin, and an ethylene-vinyl acetate copolymer are respectively thick. Those formed into a sheet having a thickness of 0.2 mm to 1.0 mm are mainly used, and the resin may contain a crosslinking aid, an ultraviolet absorber or the like. From the viewpoint of the total light transmittance, an ethylene-vinyl acetate copolymer is preferred.

  As the solar cell element (III) of the present invention, a crystalline silicon solar cell element, a polycrystalline silicon solar cell element, an amorphous silicon solar cell element, a copper indium selenide solar cell element, a cadmium tellurium solar cell element, a compound semiconductor solar A battery element can be illustrated.

The solar cell back surface sealing sheet (V) of this invention is demonstrated.
The solar cell back surface protective sheet (V) is formed by supporting a black adhesive layer (1) containing a perylene black pigment on the surface of a film (2) having an infrared reflectance of 700 to 1200 nm of 60 to 100%. It is a solar cell back surface protection sheet (V). And a black adhesive layer (1) is arrange | positioned between the film (2) which has a reflective function, and the non-light-receiving surface side sealing agent layer (IV).

  The solar cell back surface protective sheet (V) is a laminate of various plastic films and metal foils. For the layers other than the black adhesive layer (1) constituting the solar cell back surface protective sheet (V), that is, the film (2), various laminated configurations can be selected as long as the above conditions are satisfied.

Hereinafter, various aspects of the solar cell backside sealing sheet (V) will be described with reference to the drawings.
FIG. 2 shows a first embodiment in which a film (2) other than the black adhesive layer (1) constituting the solar cell backside sealing sheet (V) comprises a white film (2-1) containing a white pigment. Indicates.
As the first mode, the modes (a) to (d) can be further exemplified.

  The mode shown in FIG. 2A is as follows: black adhesive layer (1) / white film (2-1) / interlayer adhesive layer (3) / deposition layer of metal oxide or nonmetal inorganic oxide (4- 1) Interlayer adhesive layer (3) / Other film (5-1) are laminated in this order.

  The mode of (b) of FIG. 2 is black adhesive layer (1) / deposited layer of metal oxide or non-metallic inorganic oxide (4-1) / interlayer adhesive layer (3) / white color (2-1). / Interlayer adhesive layer (3) / Other film (5-1) are laminated in this order.

  The mode shown in FIG. 2 (c) is as follows: black adhesive layer (1) / white film (2-1) / interlayer adhesive layer (3) / evaporated layer of metal oxide or non-metal inorganic oxide (4- 1) or metal foil (4-2) / coating layer (5-2) is laminated in this order.

  The mode of (d) of FIG. 2 is black adhesive layer (1) / deposition layer (4-1) of metal oxide or non-metallic inorganic oxide / interlayer adhesive layer (3) / white color (2-1). / Interlayer adhesive layer (3) / coating layer (5-2) is laminated in this order.

FIG. 3 shows that the film (2) other than the black adhesive layer (1) constituting the solar cell backside sealing sheet (V) is a transparent film (2-2) -a and a white layer (2-2)- The case where b is provided is shown.
As a 2nd aspect shown in FIG. 3, the aspect of (a)-(k) can be illustrated further.

The embodiment shown in FIG. 3 (a) is a black adhesive layer (1) / transparent film (2-2) -a / white layer (2-2) -b / vapor deposition of metal oxide or non-metal inorganic oxide. The layer (4-1) or metal foil (4-2) / interlayer adhesive layer (3) / other film (5-1) is laminated in this order.
Examples of the white layer (2-2) -b include a white interlayer adhesive layer. The same applies to (b), (c), (d), (e), and (j) of FIG.

  The mode shown in (b) of FIG. 3 is as follows: black adhesive layer (1) / deposited layer of metal oxide or nonmetal inorganic oxide (4-1) / white layer (2-2) -b / transparent film ( 2-2) -a / interlayer adhesive layer (3) / other film (5-1) are laminated in this order.

  The mode shown in (c) of FIG. 3 is as follows: black adhesive layer (1) / deposited layer of metal oxide or non-metal inorganic oxide (4-1) / white layer (2-2) -b / transparent film ( 2-2) -a / coating layer (5-2) is laminated in this order.

  The mode shown in FIG. 3 (d) is as follows: black adhesive layer (1) / transparent film (2-2) -a / interlayer adhesive layer (3) / deposition layer of metal oxide or nonmetal inorganic oxide ( 4-1) / white layer (2-2) -b / other film (5-1) are laminated in this order.

  The mode shown in FIG. 3 (e) is as follows: black adhesive layer (1) / deposited layer of metal oxide or non-metallic inorganic oxide (4-1) / interlayer adhesive layer (3) / transparent film (2- 2) -a / white layer (2-2) -b / other film (5-1) are laminated in this order.

  The mode shown in FIG. 3 (f) is as follows: black adhesive layer (1) / deposited layer of metal oxide or non-metallic inorganic oxide (4-1) / interlayer adhesive layer (3) / transparent film (2- 2) -a / interlayer adhesive (3) / white layer (2-2) -b are laminated in this order. As the white layer (2-2) -b in the case of FIG. 3 (f), a white so-called protective film can be exemplified.

  The mode shown in FIG. 3 (g) is as follows: black adhesive layer (1) / deposited layer of metal oxide or non-metallic inorganic oxide (4-1) / interlayer adhesive layer (3) / transparent film (2- 2) -a / white layer (2-2) -b is laminated in this order. As the white layer (2-2) -b in the case of FIG. 3G, a white coating layer can be exemplified.

  The mode shown in (i) of FIG. 3 is as follows: black adhesive layer (1) / transparent film (2-2) -a / interlayer adhesive layer (3) / deposited layer of metal oxide or nonmetal inorganic oxide ( 4-1) The interlayer adhesive layer (3) / white layer (2-2) -b is laminated in this order. Examples of the white layer (2-2) -b in the case of (i) in FIG. 3 include a white so-called protective film and a white coating layer.

  The mode shown in (j) of FIG. 3 is the deposition of black adhesive layer (1) / transparent film (2-2) -a / white layer (2-2) -b / metal oxide or non-metal inorganic oxide. The layer (4-1) or the metal foil (4-2) / coating layer (5-2) is laminated in this order. As the white layer (2-2) -b in the case of FIG. 3J, a white interlayer adhesive can be exemplified.

  In addition, the solar cell back surface protective sheet used in the present invention can be configured as shown in FIGS.

The black adhesive layer (1) which comprises the solar cell back surface protection sheet used by this invention is demonstrated.
The black adhesive layer (1) in the present invention is a layer provided to improve the adhesion between the film (2) and the non-light-receiving surface side sealant layer (IV), and has a wavelength of 650 nm or less. It is characterized in that it contains perylene black pigment, which is a black pigment that transmits light of 650 to 900 nm or more but does not have an absorption wavelength. By containing such a perylene black pigment, it is possible to pass through the incident near-infrared rays without absorbing it even though it appears black to human eyes. And by using the reflective function of the other layers constituting the solar cell back surface protective sheet described later, that is, the film (2), the near-infrared ray is reflected and effectively used for power generation, and the solar cell back surface protective sheet itself and It can suppress that a solar cell module becomes high temperature.

The black adhesive layer (1) can be provided by various methods. For example,
A black adhesive is applied to the film to form a curable adhesive layer, and when the non-light-receiving surface side sealing agent (IV) is pasted, the above-mentioned curing is performed to cure the black adhesive layer. (1).
Alternatively, a non-light-receiving surface side sealing agent (IV), a film containing a resin capable of adhering under heating and a perylene black pigment are laminated on the film directly or via an adhesive, and the resin film is adhered to the adhesive. It can also be used as layer (1). In the latter case, for example, polyolefin resin such as polyethylene and polypropylene, fluorine resin such as polyvinyl fluoride and polyvinylidene fluoride, and ethylene-vinyl acetate copolymer are mixed with perylene black, and a T-die extruder is used. It can be obtained by using it as a film.

The black adhesive layer (1) of the present invention is characterized by containing a perylene black pigment.
Examples of the perylene black pigment include Paliogen Black and Lumogen Black manufactured by BASF Corporation.

  The perylene black pigment is preferably contained in an amount of 0.5 to 20% by weight and more preferably 1 to 10% by weight in 100% by weight of the black adhesive layer (1). If it is less than 0.5% by weight, the optical density is insufficient and it is difficult to be recognized as black in appearance. Moreover, when it exceeds 20 weight%, the fall of adhesive force may be caused. Further, the perylene black pigment preferably contains 1 to 10% by weight of the perylene black pigment per 1 μm of the thickness of the black adhesive layer (1). If it is less than 1% by weight, the optical density is insufficient, and it is difficult to recognize the color as black in appearance. Moreover, when it exceeds 10 weight%, the fall of adhesive force may be caused.

  When providing the adhesive layer (1) by a coating method, it is preferable to contain a hydroxyl group-containing resin (B). The hydroxyl value of the resin (B) having a hydroxyl group is preferably 0.1 to 50 [mg KOH / g], and more preferably 0.5 to 30 [mg KOH / g]. When there are few hydroxyl groups, the reaction point with the hardening | curing agent mentioned later will decrease, and the heat-and-moisture resistance will deteriorate because a crosslinking density falls. On the other hand, when there are many hydroxyl groups, a crosslinking density will increase and the adhesive layer (1) after hardening will harden, and the adhesive force with a filler will fall.

  Examples of the resin (B) having a hydroxyl group used in the present invention include a polyester resin (B1), a urethane resin, and an acrylic resin, and these can be used alone or in combination of two or more. Further, a composite of these resins can be used.

  The polyester resin (B1) referred to in the present invention is a polyester resin obtained by reacting a carboxylic acid component and a hydroxyl component (esterification reaction, transesterification reaction), and further reacting an isocyanate compound with a polyester resin having a hydroxyl group. And polyester polyurethane polyurea resin obtained by reacting a diamine component.

As the carboxylic acid component constituting the polyester resin (B1), benzoic acid, p-tert-butylbenzoic acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic anhydride, adipic acid, azelaic acid, tetrehydrophthalic anhydride , Hexahydrophthalic anhydride, maleic anhydride, fumaric acid, itaconic acid, tetrachlorophthalic anhydride, 1,4-cyclohexanedicarboxylic acid, trimellitic anhydride, methylcyclohexeric carboxylic anhydride, pyromellitic anhydride, ε-caprolactone, A fatty acid can be illustrated.
Examples of the hydroxyl group component constituting the polyester resin (B1) include ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, triethylene glycol, 3-ethylene glycol, In addition to diol components such as methylpentanediol and 1,4-cyclohexanedimethanol, polyfunctional alcohols such as glycerin, trimethylolethane, trimethylolpropane, trishydroxymethylaminomethane, pentaerythritol, and dipentaerythritol can be exemplified.
According to a conventional method, those obtained by polymerizing these carboxylic acid component and hydroxyl group component into a predetermined polyester resin can be used in the present invention.

The urethane-based resin referred to in the present invention is obtained by reacting a hydroxyl component other than a polyester resin having a hydroxyl group with an isocyanate compound.
Examples of the hydroxyl component include polyethylene glycol, polypropylene glycol, polymer polyols such as polyether polyols added with ethylene oxide or propylene oxide, acrylic polyols, and polybutadiene polyols.
As an isocyanate compound, the thing similar to the polyisocyanate compound (C) mentioned later can be illustrated. Trimethylene diisocyanate (TDI), hexamethylene diisocyanate (HDI), methylene bis (4,1-phenylene) = diisocyanate (MDI), 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI), xylylene diisocyanate ( XDI), trimethylolpropane adducts of these diisocyanates, isocyanurates that are trimers of these diisocyanates, burette conjugates of these diisocyanates, polymeric diisocyanates, and the like.

As a monomer constituting the acrylic resin, the general formula (a) CH ₂ = CR ₁ —CO—OR ₂ (R ₁ is a hydrogen atom or a methyl group, R ₂ is a hydroxyl group or a substituent having 1 to 20 carbon atoms). Acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-hexyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 4-hydroxybutyl acrylate, Examples include hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, butyl methacrylate, n-hexyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate, hydroxypropyl methacrylate, etc. it can. Furthermore, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, N-methylol acrylamide, N-alkylol acrylamide, diacetone acrylamide, diacetone methacrylamide, acrolein, methacrolein, glycidyl methacrylate and the like can be exemplified as reactive monomers. Those obtained by copolymerizing these monomers according to a conventional method to obtain a predetermined acrylic resin can be used in the present invention.

  As a polyester-type resin (B1) in this invention, that whose glass transition temperature (Tg) is 30-100 degreeC is preferable. When the glass transition temperature is lower than 30 ° C., tackiness occurs on the surface of the adhesive layer (1), and it becomes easy to block or durability is lowered. When it is higher than 100 ° C., the solution viscosity of the adhesion is increased, and the coating property is lowered.

The adhesive used when the adhesive layer (1) is provided by a coating method preferably contains a curing agent having a functional group capable of reacting with the hydroxyl group of the resin (B) having a hydroxyl group.
As the curing agent having a functional group capable of reacting with a hydroxyl group, an isocyanate compound is preferable. From the viewpoint of durability of the adhesive layer (1) constituting the solar cell module after curing, the isocyanate compound is a polyisocyanate compound (C). preferable.

  As the polyisocyanate compound (C) used in the present invention, conventionally known compounds can be used, and examples thereof include aromatic polyisocyanates, chain-type or cyclic aliphatic polyisocyanates, and araliphatic polyisocyanates. . Aromatic polyisocyanates include 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-triylene diisocyanate. Range isocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanatetoluene, 1,3,5-triisocyanatebenzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4 ', 4 " -Triphenylmethane triisocyanate etc. can be mentioned.

  Examples of chain aliphatic polyisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, and dodeca. Examples include methylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate and the like.

  Examples of alicyclic polyisocyanates include 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl- 2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), 1,4-bis (isocyanatomethyl) cyclohexane, and the like.

  Examples of the araliphatic polyisocyanate include ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1, 4-dimethylbenzene, ω, ω′-diisocyanate-1, 4-diethylbenzene, 4-tetramethylxylylene diisocyanate, 1,3-tetramethylxylylene diisocyanate, and the like.

  In addition to the polyisocyanate, an adduct of the polyisocyanate and a polyol compound such as trimethylolpropane, a burette or isocyanurate of the polyisocyanate, and further, the polyisocyanate and a known polyether polyol or polyester polyol, Examples thereof include adducts with acrylic polyol, polybutadiene polyol, polyisoprene polyol and the like.

  Among these polyisocyanate compounds (C), a low-yellowing type aliphatic or alicyclic polyisocyanate is preferable from the viewpoint of design, and an isocyanurate is preferable from the viewpoint of heat-and-moisture resistance. More specifically, hexamethylene diisocyanate (HDI) isocyanurate and 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI) isocyanurate are preferred.

  As the curing agent, in addition to the polyisocyanate compound (C), known oxazoline compounds such as 2,5-dimethyl-2-oxazoline, 2,2- (1,4-butylene) -bis (2-oxazoline), for example. ) Or hydrazide compounds such as isophthalic acid dihydrazide, sebacic acid dihydrazide, adipic acid dihydrazide.

  The polyisocyanate compound (C) used in the present invention may be a blocked polyisocyanate compound.

  In the adhesive layer (1) used in the present invention, the isocyanate group in the polyisocyanate compound (C) is 1.0 to 15 in terms of an equivalent ratio with respect to the total number of hydroxyl groups of the resin (B) having hydroxyl groups. It is preferable to mix | blend so that it may be set to 0, and it is more preferable to mix | blend so that it may become 1.5-10.0. When the amount of the polyisocyanate compound (C) is small, the reaction with the hydroxyl group-containing resin (B) hardly proceeds, so that it is not expected to improve the durability of the solar cell module. If the polyisocyanate compound (C) increases, the cured adhesive layer (1) becomes too hard, and the initial adhesive force with the filler is reduced.

  The adhesive layer (1) used in the present invention can further contain a resin component. By containing these resins, the moisture and heat resistance of the adhesive layer (1) can be improved.

  Specific examples of the resin include acrylic resin, urethane resin, epoxy resin, alkyd resin, ketone resin, xylene resin, olefin resin, polycarbonate resin, phenol resin, and fluorine resin.

  The adhesive layer (1) used in the present invention can further contain organic particles or inorganic particles described later. By containing these particles, tackiness on the surface of the adhesive layer (1) can be reduced.

  Specific examples of organic particles include polyolefin wax, polymethyl methacrylate resin, polystyrene resin, nylon resin, melamine resin, guanamine resin, phenol resin, urea resin, silicon resin, methacrylate resin, acrylate resin, and other polymer particles, Alternatively, cellulose powder, nitrocellulose powder, wood powder, waste paper powder, rice husk powder, starch and the like can be mentioned.

  The polymer particles can be obtained by a polymerization method such as an emulsion polymerization method, a suspension polymerization method, a dispersion polymerization method, a soap-free polymerization method, a seed polymerization method, or a microsuspension polymerization method. The organic particles may contain impurities to the extent that the characteristics are not impaired. The shape of the particles may be any shape such as powder, granule, granule, flat plate, and fiber.

  Specific examples of the inorganic particles include inorganic particles containing glass fiber, glass powder, glass beads, clay, wollastonite, iron oxide, antimony oxide, lithopone, pumice powder, aluminum sulfate, zirconium silicate, dolomite, iron sand and the like. Can be mentioned.

  Moreover, the said inorganic type particle | grain may contain the impurity to such an extent that the characteristic is not impaired. The shape of the particles may be any shape such as powder, granule, granule, flat plate, and fiber.

  The adhesive layer (1) used in the present invention preferably contains 0.01 to 30 parts by weight of the above various particles with respect to the resin (B) containing a hydroxyl group, and contains 0.1 to 10 parts by weight. More preferably. When there are few said various particle | grains, the adhesive layer (1) surface tack cannot fully be reduced. On the other hand, when the above-mentioned various particles increase, the adhesion between the adhesive layer (1) and the filler may be hindered, resulting in a decrease in adhesive strength.

Next, the film (2) which comprises the back surface protection sheet for solar cells used in this invention is demonstrated.
The film (2) is characterized by having an infrared reflectance of 700 to 1200 nm of 60 to 100%, preferably 80% or more, and more preferably 90% or more. The light in the near-infrared region that is transmitted without being absorbed by the perylene black pigment is reflected by the film (2), thereby producing a heat shielding effect and an effect of improving the photoelectric conversion efficiency.

The film (2) in the present invention comprises a white film (2-1) containing a white pigment, or comprises a transparent film (2-2) -a and a white layer (2-2) -b. It is.
The white film (2-1) may be arranged in any position of the multilayer film (2) as long as the film (2) has the near infrared reflection function as described above. It is preferable to be disposed at a position in direct contact with the black adhesive layer (1).

  Examples of the resin film used as the white film (2-1) include polyester resin films such as polyethylene terephthalate, polybutylene terephthalate, and polynaphthalene terephthalate, olefin films such as polyethylene, polypropylene, and polycyclopentadiene, polyvinyl fluoride, Fluorine-based films such as polyvinylidene fluoride films, polytetrafluoroethylene films, and ethylene-tetrafluoroethylene copolymer films, acrylic films, and triacetyl cellulose films can be used. A polyester resin film is desirable from the viewpoint of cost.

  A white film (2-1) becomes white by containing a white pigment or an extender, and can have a reflective function. By containing these pigments, the light incident on the film (2-1) is reflected on the surface or inside thereof, and the efficiency of entering the solar cell element (III) is increased.

Specific examples of the white pigment include titanium oxide, zinc oxide, white lead, and zinc sulfide.
Titanium oxide is desirable from the viewpoint of coloring power, weather resistance, and cost.

  Specific examples of extender pigments include magnesium, calcium, barium, zinc, zirconium, molybdenum, silicon, antimony, titanium, and other metal oxides, hydroxides, sulfates, carbonates, silicates, etc. Inorganic particles to be used. Further specific examples include silica gel, aluminum oxide, calcium hydroxide, calcium carbonate, magnesium oxide, magnesium hydroxide, magnesium carbonate, zinc oxide, lead oxide, diatomaceous earth, zeolite, aluminosilicate, talc, white carbon, mica Etc.

The white film (2-1) is preferably a foamed polyester film. Since foaming, that is, bubbles are also included, the reflectance in the near infrared region is increased by the difference in refractive index between the air layer and the white pigment.
A white pigment-containing white film (2-1) containing no air bubbles and a foamed polyester film containing air bubbles can be laminated and used.

  The solar cell back surface protective sheet (V) preferably further comprises a metal foil, or a vapor-deposited layer of metal oxide or non-metal inorganic oxide. These metal foils and the like responsible for the water vapor barrier property-providing function are located on the side of the white film (2-1) that does not carry the black adhesive layer (1).

The white film (2-1) and the metal foil can be laminated via an adhesive layer.
As the metal foil, aluminum foil, iron foil, zinc plywood and the like can be used. Among these, aluminum foil is preferable from the viewpoint of corrosion resistance, and the thickness is preferably 10 μm to 100 μm, and more preferably. Is preferably 20 μm to 50 μm.
Conventionally known various adhesives can be used for the lamination of the two.

The vapor deposition layer is provided on one surface of the white film (2-1). What laminated | stacked single-sided vapor deposition polyester films via the adhesive bond layer, or what laminated | stacked single-side vapor deposition polyester film and another vapor deposition film via an adhesive bond layer can also be used.
Examples of the metal oxide or non-metal inorganic oxide to be deposited include oxides such as silicon, aluminum, magnesium, calcium, potassium, tin, sodium, boron, titanium, lead, zirconium, and yttrium. Alkali metal and alkaline earth metal fluorides can also be used, and these can be used alone or in combination.
These metal oxides or non-metal inorganic oxides can be deposited using a conventionally known PVD method such as vacuum deposition, ion plating, sputtering, or the like, or a CVD method such as plasma CVD or microwave CVD.

The solar cell back surface protective sheet (V) can further include a fluororesin-containing layer for imparting weather resistance. The weather resistance imparting layer can be located on the outer side, i.e., the side opposite to the side where the white film (2-1) is provided, than the metal foil or the like responsible for the water vapor barrier property imparting function.
It is preferable that the water vapor barrier property-imparting layer and the weather resistance-imparting layer are provided on the white film (2-1) prior to the formation of the black adhesive layer (1).

Similarly to the case where the laminated film including the transparent film (2-2) -a and the white layer (2-2) -b also includes the white film, the solar cell back surface protective sheet (V) is formed.
As the white layer (2-2) -b, a white adhesive layer made white by adding a white pigment or an extender pigment to an interlayer adhesive used for bonding a transparent film and a vapor deposition layer or a weather resistance imparting layer, In many cases, a white weather resistance imparting layer in which the weather resistance imparting layer located on the most non-light-receiving surface side of the solar cell back surface protective sheet (V) is white is exemplified.
The white weather resistance imparting layer can be formed from a white coating agent excellent in weather resistance, or a white film excellent in weather resistance can be bonded using an adhesive to form a weather resistance imparting layer.
By using the white layer (2-2) -b, the white layer (2-2) -b reflects near-infrared light that has passed through the black adhesive layer (1) from the light receiving surface side and is incident on the light receiving surface side. be able to.

Next, a method for forming the black adhesive layer (1) on the white film (2-1) or the transparent film (2-2) -a by a coating method will be described.
A water vapor barrier property-imparting layer on the white film (2-1) or on the transparent film (2-2) -a, or on the white film (2-1) or on the transparent film (2-2) -a ( 4) On the multilayer film formed by laminating the weather resistance layer (5), a black adhesive is applied, and volatile products such as organic solvents are volatilized and dried to form a black adhesive layer (1). And the back surface protection sheet for solar cells of this invention can be obtained.

In the present invention, a conventionally known method can be used as a method for applying the black adhesive, and specific examples include comma coating, gravure coating, reverse coating, roll coating, lip coating, and spray coating. In this invention, the process of apply | coating an adhesive agent by these methods and volatilizing a solvent by heat drying is called coating.
The thickness of the black adhesive layer (1) to be formed is 0.1 to 10 μm .

Next, the manufacturing method of the solar cell module of this invention is demonstrated.
The solar cell module of the present invention includes a solar cell surface sealing sheet (I) positioned on the light receiving surface side of the solar cell, a sealing material layer (II) positioned on the light receiving surface side of the solar cell, and a solar cell element (III ), The sealing material layer (IV) located on the non-light-receiving surface side of the solar cell, and the back surface protection sheet (V) for solar cells described in detail as essential constituent layers, and the non-light-receiving surface side sealing material layer It can obtain by laminating | stacking a solar cell back surface sealing sheet (V) so that the black adhesive layer (1) of a solar cell back surface sealing sheet (V) may contact (IV). When laminating the non-light-receiving surface side sealing material layer (IV) and the solar cell back surface protective sheet (V), they can be obtained by bringing them into contact with each other under reduced pressure and then superposing them under heating and pressure.
When the black adhesive layer (1) is thermosetting, the black adhesive layer (1) can be cured by returning to normal pressure and then placing it under a higher temperature condition.

  Hereinafter, the present invention will be described in more detail with reference to examples. In the examples, “part” means “part by weight” and “%” means “% by weight”.

<Polyester resin solution B1>
Charge 99.6 parts of dimethyl terephthalate, 92.2 parts of ethylene glycol, 72.2 parts of neopentyl glycol, and 0.02 part of zinc acetate, and heat to 160-210 ° C. with stirring under a nitrogen stream. A transesterification reaction was carried out. After 97% of the theoretical amount of methanol was distilled, 77.5 parts of isophthalic acid and 166.9 parts of azelaic acid were charged and heated to 160 to 240 ° C. to carry out an esterification reaction. The reaction vessel was gradually reduced in pressure to 1 to 2 Torr, and when the acid value became 0.8 mgKOH / g or less, the reaction under reduced pressure was stopped. The number average molecular weight was 41,000 and the hydroxyl value was 3.2. (MgKOH / g), a polyester polyol having an acid value of 0.7 (mgKOH / g) and Tg of −10 ° C. was obtained and diluted with ethyl acetate to obtain a polyester resin solution B1-1 having a solid content of 50%. .

  Separately, polyester resin “Byron 200” (Toyobo Co., Ltd., number average molecular weight 17,000, hydroxyl value 6 (mgKOH / g), acid value 2 (mgKOH / g) or less, Tg: 67 ° C.) to methyl ethyl ketone. It melt | dissolved and obtained polyester resin solution B1-2 of 50% of solid content.

Next, the polyester resin solution B1-1 and the polyester resin solution B1-2 were mixed at a weight ratio of 1: 1 to obtain a polyester resin solution B1 having a solid content of 50% by weight.
The polyester resin in the polyester resin solution B1 had a hydroxyl value of 4.6 (mgKOH / g), an acid value of 0.8 (mgKOH / g), and a Tg of 28 ° C.

  The number average molecular weight, glass transition temperature, acid value, and hydroxyl value were measured as described below.

<Measurement of number average molecular weight (Mn)>
For the measurement of Mn, GPC (gel permeation chromatography) was used. GPC is liquid chromatography in which a substance dissolved in a solvent (THF; tetrahydrofuran) is separated and quantified by the difference in molecular size, and the number average molecular weight (Mn) is determined in terms of polystyrene.

<Measurement of glass transition temperature (Tg)>
The glass transition temperature was measured by differential scanning calorimetry (DSC).
About 10 mg of sample was weighed in an aluminum pan and set in a DSC apparatus (reference: the same type of aluminum pan without sample). After heating at 300 ° C. for 5 minutes, using liquid nitrogen − Rapid cooling was performed to 120 ° C. Thereafter, the temperature was raised at 10 ° C./min, and the glass transition temperature (Tg) was calculated from the obtained DSC chart (unit: ° C.).

<Measurement of hydroxyl value (OHV)>
About 1 g of a sample (resin solution: about 50%) is accurately weighed in a stoppered Erlenmeyer flask, and 100 ml of a toluene / ethanol (volume ratio: toluene / ethanol = 2/1) mixed solution is added and dissolved. Further, 5 ml of an acetylating agent (a solution in which 25 g of acetic anhydride was dissolved in pyridine to make a volume of 100 ml) was added and stirred for about 1 hour. To this, phenolphthalein reagent is added as an indicator and lasts for 30 seconds. Thereafter, the solution is titrated with a 0.1N alcoholic potassium hydroxide solution until the solution becomes light red.
The hydroxyl value was determined by the following formula. The hydroxyl value was a numerical value in the dry state of the resin (unit: mgKOH / g).

Hydroxyl value (mgKOH / g) = [{(ba) × F × 28.25} / S] / (Nonvolatile content concentration / 100) + D
Where S: Amount of sample collected (g)
a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)
b: Consumption of 0.1N alcoholic potassium hydroxide solution in the empty experiment (ml)
F: Potency of 0.1N alcoholic potassium hydroxide solution D: Acid value (mgKOH / g)

<Acrylic resin solution B2>
In a four-necked flask equipped with a cooling tube, a stirrer, a thermometer, and a nitrogen introduction tube, 40 parts of methyl methacrylate, 30 parts of n-butyl methacrylate, 28 parts of 2-ethylhexyl methacrylate, 1 part of 2-hydroxyethyl methacrylate, 100 of toluene The temperature was raised to 80 ° C. with stirring in a nitrogen atmosphere, 0.15 parts of azobisisobutyronitrile was added, and the polymerization reaction was carried out for 2 hours. 07 parts were added and the polymerization reaction was further carried out for 2 hours, 0.07 parts of azobisisobutyronitrile was further added and the polymerization reaction was further carried out for 2 hours, and the number average molecular weight was 25,000 and the hydroxyl value was 4.4 ( mgKOH / g), an acid value of 0 (mgKOH / g), Tg of 39 ° C., and an acrylic resin solution B2 having a solid content of 50% were obtained.

<Polyester resin solution B3>
117 parts of diethylene glycol, 319 parts of neopentyl glycol, 192 parts of isophthalic acid, 188 parts of terephthalic acid, and 214 parts of adipic acid are charged into a reaction can and heated to 160-240 ° C. with stirring under a nitrogen stream to carry out an esterification reaction. It was. The reaction vessel was gradually reduced in pressure to 1 to 2 Torr, and when the acid value became 1 mgKOH / g or less, the reaction was stopped under reduced pressure, the number average molecular weight was 10,000, and the hydroxyl value was 19 (mgKOH / g ), A polyester resin having an acid value of 0.9 (mg KOH / g) and a Tg of 0 ° C. was obtained and diluted with ethyl acetate to obtain a polyester resin solution B3 having a solid content of 50%.

<Curing agent solution>
A trimer of isophorone diisocyanate blocked with MEK oxime and a trimer of hexamethylene diisocyanate blocked with MEK oxime were mixed at a weight ratio of 1: 1 and diluted with ethyl acetate to give a solid content of 50%. The resin solution is used as a curing agent solution.

<Adhesive adjustment>
The black pigment (A), the resin solution (B) having an acid value, the curing agent solution (C), and the pigment were mixed in the composition shown in Table 1 to obtain adhesives 1 to 7.
Each black adhesive was applied to Toyobo Co., Ltd., Tetron S, thickness 188 μm, hereinafter referred to as “transparent substrate A”) and dried to prepare a 10 μm adhesive layer. Using a total V-570 (manufactured by JASCO Corporation), the transmittance in the wavelength range of 600 to 1200 nm was measured.

As an example of a specific solar cell back surface protective sheet, although a laminated structure is illustrated in Tables 2 and 3, it is not limited to the laminated structure.

[Example 1]
<Creation of back surface protection sheet for solar cell>
Polyester adhesive “Dyna Leo VA-3020 / HD-701” (Toyo Ink Co., Ltd.) on one side of a white pigment-containing white polyester film (Toray Industries, Lumirror E20, thickness 50 μm, hereinafter referred to as “white substrate B”) ), A blending ratio of 100/7, the same applies hereinafter) with a gravure coater, the solvent is dried, an adhesive amount of 10 g / square meter is provided, and the following deposited PET (Mitsubishi resin) is applied to the adhesive layer. The vapor-deposited surfaces manufactured by Co., Ltd., Tech Barrier LX, thickness 12 μm) were superposed. Thereafter, an aging treatment was performed at 50 ° C. for 4 days to cure the adhesive layer, and a white base material B-deposited PET laminate was prepared.

Further, a polyester adhesive “Dyna Leo VA-3020 / HD-701” was applied to the vapor deposition film surface of the white base material B-deposited PET laminate with a gravure coater, the solvent was dried, and an adhesive amount of 10 g / square meter was applied. A polyvinyl fluoride film (manufactured by DuPont, Tedlar, thickness 50 μm, hereinafter referred to as “protective film A”) was superposed on the adhesive layer.
Thereafter, an aging treatment was performed at 50 ° C. for 4 days to cure the adhesive layer, and a white base material B-deposited PET-polyvinyl fluoride film laminate was prepared.
Using a spectrophotometer V-570 (manufactured by JASCO), the reflectance of the white base material B-deposited PET-polyvinyl fluoride film laminate obtained from the white base material B side was measured in the wavelength range of 600 to 1200 nm.

  Further, the black adhesive 1 listed in Table 1 is applied to the side of the white base B of the white base B-deposited PET-polyvinyl fluoride film laminate by a gravure coater, the solvent is dried, and the coating amount is 4 g / square meter. The layer was provided and the back surface protection sheet 1 for solar cells was created.

<Measurement of adhesive strength>
Two sheets of the back protection sheet 1 for the solar cell are prepared, and two sheets of the EVA sheet are provided so that the adhesive layer is in contact with both surfaces of the EVA sheet (thickness 450 μ, standard cure type, hereinafter the same) manufactured by Sanvic Co., Ltd. Adhesive strength measurement is performed by sandwiching the backside protective sheet 1 for solar cells with a vacuum laminator at a temperature of 150 ° C., a deaeration time of 5 minutes, a press pressure of 1 atm, a press time of 10 minutes, and an after cure of 150 ° C. for 15 minutes. A sample was prepared.
A part of the sample for measuring the adhesive force was subjected to a pressure cooker test for 48 hours under an environmental condition of a temperature of 121 ° C., a relative humidity of 100% RH, and 2 atmospheres.
Those that were not subjected to the pressure cooker test (initial) and those that were tested (after wet heat aging) were each cut into a 15 mm wide rectangle to obtain test pieces. Each test piece was subjected to a T-peeling test using a tensile tester at a load speed of 100 mm / min.
○: 20 N / 15 mm or more Δ: 5 N / 15 mm or more to less than 20 N / 15 mm ×: less than 5 N / 15 mm

<Measurement of chromaticity>
The chromaticity was measured with a color system such as Lab from the black adhesive surface side of the back protective sheet 1 for solar cells using a color difference meter CR-300 (manufactured by Konica Minolta).

<Measurement of reflectance>
The reflectance was measured in the wavelength range of 600 to 1200 nm from the black adhesive surface side of the back protective sheet 1 for solar cells using a spectrophotometer V-570 (manufactured by JASCO).

<Heat insulation test>
The heat shielding property is such that a black paper cut to 70 mm x 70 mm is placed on a styrene foam box with a length of 280 mm, a width of 465 mm, and a height of 190 mm in a room adjusted to a room temperature of 23 ° C, and further overlapped with the black paper. The solar cell back surface protection sheet 1 cut to 70 mm × 70 mm is placed on the surface, and a 125 W infrared lamp is irradiated from a point 15 cm directly above the solar cell back surface protection sheet 1, and the temperature inside the point 10 cm directly below the coating film. The rise was measured.

<Creation of solar cell module>
White glass ... Solar cell surface sealing sheet (I)
Vinyl acetate-ethylene copolymer film (EVA) ... Light-receiving surface side sealing material layer (II)
Polycrystalline silicon solar cell element ... solar cell element (III)
EVA non-light-receiving surface side sealing material layer (IV)
After the solar cell back surface protective sheet 1 is stacked, it is put into a vacuum laminator, evacuated to about 1 Torr, and heated at 150 ° C. for 30 minutes under a pressure of atmospheric pressure as a press pressure, and further at 150 ° C. The solar cell module 1 for photoelectric conversion efficiency evaluation of 10 cm x 10 cm square was produced by heating for 30 minutes.

<Measurement of photoelectric conversion efficiency>
The solar cell output of the obtained solar cell module 1 was measured, and the photoelectric conversion efficiency was measured using a solar simulator (SS-100XIL, manufactured by Eihiro Seiki Co., Ltd.) according to JISC8912.

[Examples 2-19], [Comparative Examples 1-2]
In the same manner as in Example 1, a solar cell back surface protective sheet 2-19 was prepared, and an adhesive strength, chromaticity, and reflectance measurement test and a heat shielding test were performed.
In the same manner, a solar cell module was prepared and the photoelectric conversion efficiency was obtained.
In Tables 4 and 5,
White foam base C: manufactured by Toyobo Co., Ltd., Crisper K1212, thickness 50 μm
Protective film B: manufactured by Toray Industries, Inc., Lumirror X10S, thickness 50 μm
Protective coating solution C: Mikuni Paint, Spula # 005 UV, thickness 15 μm

[Example 20]
A polyester adhesive “Dyna Leo VA-3020 / HD-701” (manufactured by Toyo Ink Mfg. Co., Ltd., compounding ratio 100/7, hereinafter the same) is applied to one surface of the white substrate B with a gravure coater, and the solvent is dried. Application amount: An adhesive layer of 10 g / square meter was provided, and an aluminum foil of 38 μm was superposed on the adhesive layer. Thereafter, an aging treatment was performed at 50 ° C. for 4 days, the adhesive layer was cured, and a white base material B-aluminum foil laminate was prepared.
Further, a polyester adhesive “Dyna Leo VA-3020 / HD-701” was applied to the aluminum surface of the white base material B-aluminum foil laminate by a gravure coater, the solvent was dried, and an adhesive layer of 10 g / square meter was applied. A polyvinyl fluoride film (manufactured by DuPont, Tedlar, thickness 50 μm) was superimposed on the adhesive layer. Thereafter, an aging treatment was performed at 50 ° C. for 4 days to cure the adhesive layer, and a white base material B-aluminum foil-polyvinyl fluoride film laminate was prepared.
Furthermore, the white base B-aluminum foil-polyvinyl fluoride film laminate is coated with the polyester adhesive “Dyna Leo VA-3020 / HD-701” with a gravure coater on the white base B surface, the solvent is dried, and the curable adhesive Layer-white substrate B-aluminum foil-polyvinyl fluoride film laminate was obtained.
Using a spectrophotometer V-570 (manufactured by JASCO Corporation), the reflectance of the curable adhesive layer-white substrate B-aluminum foil-polyvinyl fluoride film laminate obtained from the white substrate B side was measured at a wavelength of 600 to 1200 nm. Measured in range.
The black adhesive sheet 1 was overlaid on the adhesive layer to create a back surface protection sheet 20 for solar cells.

In the same manner as in Example 1-19, an adhesive strength, chromaticity, and reflectance measurement test of the solar cell back surface protective sheet 20 and a heat shielding test were performed.
Furthermore, it carried out similarly to Example 1, the solar cell module was created, and the photoelectric conversion efficiency was calculated | required.

As shown in Table 4, Examples 1 to 19, having a perylene black pigment in the adhesive layer (1), since almost the same color as the solar cell element, without impairment of the appearance of the module. Furthermore, the solar cell module has a heat shielding function because the near infrared light transmitted without being absorbed by the solar cell element is transmitted through the adhesive layer (1) and reflected by the film (2) having a reflection function. As a result, output degradation during the day can be suppressed.
Since the comparative example 1 using the carbon black pigment which absorbs infrared rays cannot reflect near-infrared rays, it is considered that the temperature of the solar cell module is increased and the output is reduced in the daytime. Comparative Example 2 having no reflection function transmits near infrared rays because the adhesive layer (1) is a perylene black pigment, but absorbs near infrared rays when the installation location of the module is black. The temperature may rise.
Therefore, the solar cell module using the solar cell back surface protective sheet of the present invention can suppress a decrease in photoelectric conversion efficiency due to an increase in temperature during the daytime.
In Example 6, since the adhesive layer (1) has a perylene black pigment and the film (2) has a reflection function, the reflectance in the near infrared region is high as in the other examples. Since the glass transition temperature of the resin (B) having a hydroxyl group used for forming the agent layer (1) was low, the adhesive strength after wet heat is reduced.

As shown in Table 4, since Examples 1 to 19 have a perylene black pigment in the adhesive layer (1), the near-infrared rays that the solar cell element could not absorb absorbed the adhesive layer (1). Since the light is transmitted and reflected by the film (2) having a reflection function, it can be incident again on the solar cell element, so that the photoelectric conversion efficiency is improved.
Comparative Example 1 using a carbon black pigment that absorbs infrared rays and Comparative Example 2 that does not have a reflection function cannot reflect near infrared rays, so that the near infrared rays cannot be incident again on the solar cell element, and the photoelectric conversion efficiency is improved. There is nothing to do.

(I): Solar cell surface sealing sheet positioned on the light receiving surface side of the solar cell (II): Sealing material layer positioned on the light receiving surface side of the solar cell (III): Solar cell (IV): Solar cell Sealant layer located on the non-light-receiving surface side (V): Solar cell back surface protection sheet (1), (1 ′): Located on the surface of the solar cell back surface protection sheet (V), the solar cell back surface protection sheet (V ) And an encapsulant layer (IV) located on the non-light-receiving surface side of the solar cell, and an adhesive layer (1) containing perylene black
(2): Films other than the adhesive layer (1) containing perylene black and constituting the solar cell back surface protective sheet (V) and having a near infrared reflection function (2-1): Near infrared reflection A white film containing a white pigment constituting a functional film (2) (2-2) -a: A transparent film constituting a film (2) having a near infrared reflection function (2-2) -b: White adhesive layer or white coating layer constituting the film (2) having a near-infrared reflecting function (3): Interlayer adhesive layer constituting the solar cell back surface protective sheet (V), which passes near infrared rays Adhesive layer having neither function nor reflection function (4-1): Deposition layer of metal oxide or nonmetal inorganic oxide constituting solar cell back surface protective sheet (V) (4-2): Sun Battery back protection Metal foil (5-1) constituting the sheet (V): Weather resistance imparting film constituting the solar cell back surface protective sheet (V) (5-2): Constructing the solar cell back surface protective sheet (V) , Weather-resistant coating layer

Claims (9)

Solar cell surface sealing sheet (I) positioned on the light receiving surface side of the solar cell, sealing material layer (II) positioned on the light receiving surface side of the solar cell, solar cell (III), non-light receiving surface side of the solar cell A solar cell module comprising a solar cell back surface protection sheet (V) formed in contact with the sealant layer (IV) positioned at the surface and the non-light-receiving surface side sealant layer (IV),
The solar cell back surface protection sheet (V)
A black adhesive layer (1) provided by a coating method on the surface of a film (2) having an infrared reflectance of 700 to 1200 nm of 60 to 100%, containing a perylene black pigment, and having a thickness of 0. 1 to 10 μm carrying a black adhesive layer (1),
The black adhesive layer (1) is in contact with the non-light-receiving surface side sealant layer (IV),
A solar cell module characterized by that.
  The film (2) comprises a white film (2-1) containing a white pigment, or a transparent film (2-2) -a and a white adhesive layer or white coating layer (2-2)- The solar cell module according to claim 1, further comprising b.   The solar cell module according to claim 2, wherein the white film (2-1) or the transparent film (2-2) -a is a polyester film.   The solar cell module according to claim 3, wherein the white film (2-1) is a foamed polyester film.   The white film (2-1) and the black adhesive adhesive layer (1) are in direct contact, and the other side of the white film (2-1) not in contact with the black adhesive adhesive layer (1) is metal 5. The solar cell module according to claim 3, further comprising at least one of a foil or a vapor-deposited layer of a metal oxide or a nonmetal inorganic oxide.   The solar cell module according to any one of claims 1 to 5, wherein perylene black pigment is contained in an amount of 0.5 to 20% by weight in 100% by weight of the black adhesive layer (1).   The solar cell module according to any one of claims 1 to 6, characterized in that it contains 1 to 10% by weight of perylene black pigment per 1 µm of thickness of the black adhesive layer (1).   The black adhesive layer (1) is formed from an adhesive containing a resin (B) having a hydroxyl group and a polyisocyanate compound (C). Battery module. The solar cell module according to any one of claims 1 to 8 , wherein the non-light-receiving surface side sealant layer (IV) is an ethylene-vinyl acetate copolymer filler layer.

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