JP2009170772A - Solar cell back sheet and solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar cell back sheet for achieving a solar cell module which has various characteristics required for protecting contents, can be molded and machined by a general-purpose method, is manufactured at a low cost and excellent in safety and durability, specifically has stable and high power conversion efficiency. <P>SOLUTION: The solar cell back sheet is a laminate having plastic films laminated on both surfaces of metal foil and the plastic film contains a heat-conductive filler, wherein the heat-conductive filler is one selected from a silicon oxide, an aluminum oxide, a boron nitride, a silicon nitride and an aluminum nitride. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a solar cell sheet member, and more particularly to a material used by being arranged on the back side of a solar cell module. More specifically, it is excellent in heat resistance, weather resistance, gas barrier properties related to water vapor, oxygen gas, etc., durability, and other physical properties, and also has the effect of suppressing the increase in module temperature and suppressing the decrease in electromotive force of the solar cell. The present invention relates to a battery back sheet and a solar cell module using the same.

  Solar cells constitute the heart of a photovoltaic power generation system that directly converts solar energy into electricity, and are made of semiconductors. In addition, the structure does not use a single solar cell element (cell) as it is, but generally several to several tens of solar cell elements are wired in series or in parallel, and the element is extended over a long period of time. Various packaging for protection is applied and unitized. FIG. 1 shows a cross-sectional explanatory diagram of an example of the configuration.

A unit incorporated in this package is called a solar cell module, and a surface to which sunlight is applied is generally covered with a front glass, and a gap is filled with a filler made of a thermoplastic plastic. The back surface is protected by a sheet (back sheet) made of heat resistant, moisture resistant, water resistant, weather resistant plastic material or the like.
Since these solar cell modules are used outdoors, in their configuration, material structure, etc., sufficient heat resistance, weather resistance, water resistance, moisture resistance, wind pressure resistance, light resistance, rainfall resistance, chemical resistance, Moisture resistance, antifouling properties, light reflectivity, light diffusibility, and other properties are required.
The solar cell module, for example, produces a crystalline silicon solar cell element or an amorphous silicon solar cell element, and uses such a solar cell element as a surface protection sheet layer, a filler layer, a photovoltaic element. A solar cell element, a filler layer, a back surface protective sheet layer, and the like are laminated in this order, and are manufactured by using a lamination method in which vacuum suction is performed and thermocompression bonding is performed.

The structure of an example of the general structure is shown in a cross-sectional explanatory view (FIG. 1).
In FIG. 1, a module is formed by laminating a front glass (surface protective sheet) 1, a filler 2, a solar cell element 3, and a back sheet 4 in this order from the light receiving side (surface), and leads between the solar cell elements. The electric power is taken out from the terminal box 7 by connecting with the wire 5. In order to fix these components as a module, the structure is surrounded by an aluminum frame 8 via a seal material 6.
As a typical manufacturing method of the solar cell module of this example, the front glass 1 is sequentially filled with about half of the filler layer 2, the solar cell element 3, about half of the filler layer 2, and the back sheet for the solar cell module. There is a method of manufacturing a solar cell module using the above-mentioned layers as an integral molded body by using a normal molding method such as a lamination method in which 4 are stacked and then vacuum sucked and heat-pressed.

  Among the components of this solar cell module, the backsheet is excellent in mechanical strength to protect the contents of the solar cell element and lead wires, etc., and has weather resistance, heat resistance, water resistance, light resistance, Excellent properties such as wind pressure resistance, drought resistance, chemical resistance, moisture resistance, antifouling properties, etc. Especially, it has a high barrier property to prevent intrusion of moisture, oxygen, etc., and minimizes long-term performance deterioration Therefore, it is required to be a back sheet that constitutes a solar cell module that is highly durable, low in cost and safe.

In order to realize these various characteristics, a heat-resistant plastic film is widely used as a back sheet for the solar cell module, taking advantage of its high insulating properties and easy secondary processing such as vapor deposition and coating. Various laminated sheets in which layers for improving performance are laminated in addition to a single-layer plastic sheet have been proposed.

  As an example of a laminated sheet, as described in Patent Document 1, a protective sheet for a solar cell module in which a vapor-deposited thin film of an inorganic oxide is provided on one side of a fluorine-based resin sheet can be used as a back sheet. Proposed.

  For example, a laminate sheet having a configuration of polyvinyl fluoride (PVF) / polyethylene terephthalate (PET) / polyvinyl fluoride (PVF), which takes advantage of the high resistance of fluororesin, is representative. Furthermore, in order to enhance the content protection of the versatile polyethylene terephthalate (PET), a structure like a PET / PET inorganic oxide vapor deposition sheet / PET provided with an inorganic oxide vapor deposition thin film layer in the middle of PET. The laminated sheet is also used.

  Furthermore, in order to further increase the durability of the module, by using a protective sheet for a solar cell module provided with a vapor-deposited thin film of an inorganic oxide on one side of a fluorine-based resin sheet as a back surface protective sheet (back sheet), adhesion and Attempts have also been made to improve various properties such as barrier properties to ensure content protection and durability (Patent Document 1).

  Specifically, a fluorine-based resin sheet is used as a base sheet, and a transparent glassy inorganic oxide vapor-deposited thin film such as silicon oxide or aluminum oxide is provided on one side thereof for a solar cell module. A protective sheet is manufactured and used as a back sheet for a solar cell module.

  For example, the surface of the surface protection sheet for solar cell module with the surface of the vapor-deposited thin film of inorganic oxide inside, the filler layer, the solar cell element as the photovoltaic element, the filler layer, and the back sheet for the solar cell module Layers are sequentially stacked.

  Next, a solar cell module is manufactured using a lamination method or the like in which these are vacuum-sucked together and heat-pressed, and the solar cell module is excellent in sunlight permeability, strength, weather resistance, and heat resistance. Excellent properties such as water resistance, light resistance, wind pressure resistance, yield resistance, chemical resistance, moisture resistance, antifouling property, etc., especially improve the barrier properties to prevent the entry of moisture, oxygen, etc. It has been proposed to stably manufacture a solar cell module that minimizes its long-term performance degradation, is extremely durable, has excellent protection capability, and is safer at lower cost.

  In addition to the above, there have been many proposals for the lamination structure of the backsheet material for the purpose of maintaining the mechanical strength and content protection of the solar cell module for a long period of time. There are few ideas about.

  Patent Document 2 has various properties required for content protection, excellent incident light reflectivity, can be molded and processed by a general-purpose method, is low-cost, safe, and excellent in durability. For the purpose of realizing a solar cell module with high power conversion efficiency, a solar cell backsheet characterized by comprising a base film, a white ink layer, and an inorganic vapor deposition film has been proposed.

  In this document, among the characteristics required for the back sheet of the solar cell module, the solar cell and lead wires inside the module are protected by the base film and the inorganic oxide vapor deposition film, and the incident light is protected by the white ink layer. It is reflected to increase the power generation efficiency of the solar battery cell. Another effect of the white ink layer is that it prevents the temperature rise due to photothermal conversion by reflecting on the back sheet surface without absorbing incident light, thereby suppressing degradation of elements inside the module. .

  As a characteristic affected by the temperature rise of the solar battery module, it is known that the power generation efficiency of the solar battery cell is reduced in addition to the lifetime. In particular, it is known that when a crystalline silicon solar cell element is used, the power generation efficiency is reduced with a rise in temperature inside the module, leading to a reduction in output. This phenomenon is particularly remarkable when the solar cell module is used in summer.

  As can be seen from the structure of the solar cell module, a back sheet is used on the back side to perform the protection function of the module, but this back sheet is usually a plastic sheet or a laminate for the purpose of protecting the contents, and generally heat conduction is not bad.

  For this reason, the heat generated inside the solar cell module is less dissipated to the outside and accumulates inside and becomes a factor that raises the internal temperature.

  In patent document 3, as a back surface protection sheet for solar cells, it has heat resistance, weather resistance, moisture resistance, and other required functions, and a structure in which an inexpensive heat and weather resistant plastic film made of polyester resin is laminated. As a laminate, a heat- and weather-resistant plastic film made of a polyester resin having an intrinsic viscosity of 0.6 (dl / g) or more and a cyclic trimer content of 0.5% by weight or less is used. A solar cell back surface protective sheet sandwiched from both sides has been proposed.

  One of the reasons for using metal foil for solar cell backsheets is that it has excellent content protection, especially water vapor and oxygen barrier properties. Expected to dissipate.

  On the other hand, this sheet structure in which both sides of a metal foil are sandwiched with a plastic film easily causes troubles such as breakage due to heat and short circuit caused by molding. In order to prevent this, the back sheet of Patent Document 3 is composed of a laminate having a structure in which metal foil is sandwiched from both sides by a heat-resistant plastic film that is not easily broken at the molding temperature.

  For this reason, heat dissipation from the back sheet was hindered by a plastic film sandwiching both sides of the metal foil. As a result, it was inevitable that the internal temperature during use would be affected, particularly the solar cell output would decrease.

  The thermoplastic resin that constitutes a normal plastic sheet has a low thermal conductivity, so it cannot diffuse the generated heat efficiently, and is partially developed due to the recent trend toward higher output of electrical and electronic components. Is actually limited. In order to solve these problems, various improvement methods have been proposed so far.

  One method is to use a thermally conductive filler as a filler for a thermoplastic resin film, and many methods including examples disclosed in Patent Document 4 have been proposed. By using this thermal conductive filler, the thermal conductivity of the sheet containing it can be improved by several tens of times compared to the case where the thermal conductivity of the sheet containing it is not included, and can be further improved by devising the contact path and the contact area between the fillers. It is also known.

  However, when such a method using a thermally conductive filler is used for a back sheet of a solar cell module, the thermal conductivity of the sheet improves as the content of the thermally conductive filler increases, but the barrier property of the sheet decreases. Face the problem of In other words, when an amount is added so that the effect of increasing the thermal conductivity of the sheet by the addition of the thermal conductive filler is noticeable, the mechanical strength and the content protection performance, which are the original purposes of the backsheet, have barrier properties. The result is that it cannot be maintained due to the decline.

As described above, in the prior art, the content protection function required for the solar battery back sheet, typically, moisture resistance or the like to prevent corrosion of cells and wiring that cause a decrease in the output of the solar battery. In addition to having weather resistance that can withstand long-term outdoor use, there remains a problem in that it effectively prevents a decrease in power generation efficiency due to a higher temperature of the module.
JP 2000-188212 A JP 2006-210557 A JP 2002-134770 A JP 2007-302822 A

  It has various properties required for content protection, can be molded and processed by general-purpose methods, is low-cost, safe, and has excellent durability. Especially, it reduces power conversion efficiency due to temperature rise inside the module. It is a problem to provide a solar battery back sheet that realizes a solar battery module that can be effectively suppressed.

  In order to solve the above problems, the solar cell backsheet of the present invention has the following configuration.

  The invention according to claim 1 is a solar battery backsheet, characterized in that the plastic film is a laminated body in which the plastic film is a film containing a thermally conductive filler.

  The invention according to claim 2 is the solar battery backsheet according to claim 1, wherein a vapor-deposited thin film layer of an inorganic oxide is formed on at least one surface of a plastic film containing a thermally conductive filler.

  The invention according to claim 3 is the solar cell backsheet according to claim 1 or 2, wherein the thermally conductive filler is at least one of silicon oxide, aluminum oxide, boron nitride, silicon nitride, and aluminum nitride. It is.

  Invention of Claim 4 is a solar cell module characterized by using the laminated body on which the plastic film containing the heat conductive filler of any one of Claim 1 to 3 was laminated | stacked as a back sheet. is there.

  According to the solar cell backsheet of the present invention, a solar cell module is obtained that is excellent in heat resistance, weather resistance, gas barrier properties relating to water vapor, oxygen gas, etc., durability and other physical properties, and has good manufacturability and cost. I can do it. In particular, it is possible to provide a solar cell module capable of preventing temperature rise by dissipating heat generated inside the module to the outside, preventing deterioration of components due to temperature rise, and suppressing output drop.

Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an explanatory cross-sectional view of an example of the configuration of a solar cell module. FIG. 2 is a cross-sectional explanatory view of an example of the configuration of the solar battery backsheet.

  Invention of Claim 1 is a sheet | seat used for the back surface protection of a solar cell module, Comprising: It is a laminated body on which the plastic film containing a heat conductive filler was laminated | stacked, It is a solar cell backsheet characterized by the above-mentioned.

  As shown in FIG. 2, the layer structure of the solar battery backsheet showing one embodiment of the present invention is a plastic film, an inorganic oxide vapor-deposited thin film layer, an adhesive layer, an inorganic oxide vapor-deposited thin film layer, and a plastic. It has a laminated structure in which films are sequentially laminated.

  The plastic film used for the solar cell backsheet of the present invention is a polyester film such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT) or polyethylene naphthalate (PEN), or a polyolefin such as polypropylene (PP) or polyethylene (PE). A film or a film such as polyphenylene sulfide (PPS) can be appropriately selected.

  There are no particular restrictions on selecting a film to be used in the present invention from the above plastic films, but the following three conditions are considered as conditions to be considered.

  One is an object of the present invention relating to the degree to which the heat inside the solar cell module is dissipated from the back surface to the outside. Among the plastic films, the inner film and the outer film, more precisely, the inner film. It is desirable to change the color of the inner surface and the outer surface of the outer film because the efficiency of heat dissipation increases. For example, the inner surface is white and the outer surface is black. However, if the inner surface is white, reflection of incident light increases inside the module, and an increase in power generation efficiency can be expected at the same time. From the viewpoint of heat dissipation, it is preferable that the thickness of the plastic film is as thin as possible within a range that satisfies other necessary conditions.

  Second, by not using metal foil, which is a useful means to ensure barrier properties, the back sheet warps and deforms due to heating in the module manufacturing process, breaks the plastic sheet, and troubles such as wiring shorts. However, there is a decrease in the heat dissipation function of the module that has relied on the high thermal conductivity of the metal foil.

  The limit of addition of the thermally conductive filler to the plastic film for ensuring this heat dissipation function varies depending on the respective resin and molding conditions.

  The plastic film can be laminated by a known method such as a dry laminating method. As for the adhesive used for the adhesive layer 10, the adhesive strength between the plastic films 9 and 11 containing the heat conductive filler and the inorganic oxide vapor-deposited thin film layer 12 is deteriorated by long-term outdoor use, and does not cause delamination. In addition, it is necessary that the adhesive does not turn yellow, and a urethane-based adhesive can be used.

  Moreover, when a solar cell backsheet is comprised with these sheets, you may use by a sheet | seat single layer and may laminate | stack and use two or more.

  A second aspect of the present invention is the solar cell backsheet according to the first aspect, wherein a vapor-deposited thin film layer of an inorganic oxide is formed on at least one surface of a plastic film containing a thermally conductive filler.

  Vapor deposition of an inorganic oxide for improving the barrier property of the original plastic sheet and preventing the barrier property from being lowered by the addition of the heat conductive filler may be performed as follows.

For the above plastic film, for example, corona discharge treatment, ozone treatment, oxygen gas or nitrogen gas is used to improve the adhesion between the substrate surface and the deposited thin film layer of inorganic oxide, if necessary. Pretreatments such as low temperature plasma treatment, glow discharge treatment, oxidation treatment using chemicals, etc., etc. can be optionally applied.

  Furthermore, a primer coating agent layer, an undercoat agent layer, an adhesive layer, an anchor coating agent layer, or the like can be arbitrarily formed in advance on the plastic film surface, and pretreatment by surface coating can be performed.

  Examples of the pretreatment coating agent layer include polyester resins, polyamide resins, polyurethane resins, epoxy resins, phenol resins, (meth) acrylic resins, polyvinyl acetate resins, polyethylene, and polypropylene. A resin composition containing as its main component a polyolefin resin or a copolymer or modified resin thereof, a cellulose-based resin, or the like can be used.

  In the pretreatment, the coating agent layer can be formed by, for example, a solvent type using a solvent as a solvent, an aqueous type using water as a solvent, or an emulsion type using water as a dispersion medium. The coating agent can be used for coating using a roll coating method, a gravure coating method, a kiss coating method, or other coating methods.

  As an inorganic oxide vapor-deposited thin film, it can be used as long as it is a thin film in which a metal oxide is vapor-deposited. However, from the viewpoint of price, effect, generality, etc., preferred are silicon (Si), Examples thereof include metal oxides such as aluminum (Al) and magnesium (Mg) or copper (Cu) deposited thin films.

  The film thickness of the inorganic oxide thin film varies depending on the metal used or the type of metal oxide, but is arbitrarily selected within the range of, for example, 50 to 2000 mm, preferably 100 to 1000 mm. It is desirable to form.

  As a method of forming a vapor-deposited thin film of inorganic oxide, it is typically formed by a normal vacuum vapor deposition method, but other thin film formation methods such as sputtering, ion plating, and plasma vapor deposition ( CVD) or the like can also be used.

  A third aspect of the present invention is the solar cell backsheet according to the first or second aspect, wherein the thermally conductive filler is at least one of silicon oxide, aluminum oxide, boron nitride, silicon nitride, and aluminum nitride.

  As fillers that can be used in the present invention, among the fine particles that can be generally kneaded and molded with plastic, those that are chemically inert and have heat resistance and thermal conductivity higher than that of plastic are targeted. Can be.

  In the present invention, it is preferable to include a thermally conductive filler having a thermal conductivity of 20 W / mK or more in order to impart higher thermal conductivity. The upper limit of the thermal conductivity of the filler is preferably 1000 W / mk in consideration of productivity and versatility. The blending amount of the heat conductive filler is preferably 30% by weight or more with respect to 100% by weight of the resin component.

  Specific examples of such a thermally conductive filler include metal powder, metal flake, metal ribbon, metal fiber, beryllia, aluminum oxide, zinc oxide, magnesium oxide and other metal oxides, aluminum nitride, boron nitride, silicon nitride, etc. Examples thereof include nitrides, inorganic fillers coated with a heat conductive material, carbon powder, graphite, pitch-based carbon fibers, PAN-based carbon fibers having a relatively high graphitization degree, scaly carbon, and carbon nanotubes.

  Among these substances, silicon, aluminum, and boron nitrides are widely known to have electrical insulation, easily obtain fine-grained products, and are chemically stable. And oxides of silicon and aluminum. By using these substances as fillers for the film constituting the solar cell module backsheet, the thermal conductivity of the backsheet can be improved.

  A fourth aspect of the present invention is a solar cell module using the solar cell backsheet according to any one of the first to third aspects.

  A cross-sectional explanatory view of an example in which a solar cell module is created using the solar cell backsheet 4 of the present invention will be described with reference to FIG. A front glass 1, a filler 2, a solar cell element 3, a lead wire 5, a terminal box 7, a solar cell back sheet 4, and an aluminum frame 8 are formed in this order in the thickness direction.

  The front glass 1 has good light transmittance, excellent weather resistance over a long period of time (about 20 years), little decrease in light transmittance, resistance to dust and the like, resistance to scratches, and water vapor. It is necessary to have various functions such as extremely low transmittance. As a material, glass is generally used, but acrylic resin, polycarbonate resin, silicone resin, fluorine resin, and the like are also used.

  The filler 2 has a high transmittance of sunlight, no long-term outdoor standing, no change in physical properties such as a decrease in light transmittance, high insulation resistance, no corrosion of other materials, and abrupt It must have various functions such as the prevention of cracking of the resin due to changes in the outside air conditions, interfacial peeling, etc., and polyvinyl butyral resin, silicone resin, vinyl chloride resin, polyurethane resin, etc. can be used. A polymer resin is preferably used. As the frame 8, an aluminum mold is generally used.

Although the specific Example of the solar cell backsheet 4 of this invention and the solar cell module produced using this backsheet is described, this invention is not limited to these Examples.
<Example 1>
As a plastic film for use in the solar battery backsheet of the present invention, a polyphenylene sulfide (PPS) resin film (special PPS film) 9 having a thickness of 100 μm and containing a fine powder filler of aluminum nitride produced by extrusion is dried on one side. Using a laminating machine, a coating amount in a dry state of a polyurethane adhesive (base Takelac A515 / curing agent Takenate A50 = 10/1 solution) manufactured by Takeda Pharmaceutical Co., Ltd. with a solid content of 30% by weight is 4.0 g / m ^2. As a result, the anchor coat layer 10 was formed.

  This laminate is mounted on a take-up roll of a take-up vacuum deposition apparatus, and then fed out onto a coating drum, and silicon oxide is deposited under conditions of a processing temperature of 1000 ° C. and a cooling drum temperature of −40 ° C. The solar cell back of the present invention is formed by forming a silicon oxide vapor deposition thin film 11 having a thickness of 500 mm on the anchor coat layer surface of the polyphenylene sulfide (PPS) resin film by a reactive vacuum vapor deposition method using a resistance heating method. Sheet 4 was created.

Subsequently, the solar cell element 3 connected in advance is placed on the front glass 1 on which a 400 μm-thick ethylene-vinyl acetate filler sheet is laid, and another filler sheet of the same material is placed thereon. Then, the solar cell back sheet 4 of the present invention is placed thereon so that the inorganic oxide deposition surface faces down, and the whole is heat-pressed at 150 ° C. for 10 minutes under reduced pressure, and the solar cell back sheet 4 is fused and integrated. Then, the end portion was fixed with an aluminum frame 8 to produce a solar cell module having the configuration shown in FIG.
<Example 2>
As a plastic film used for the solar battery backsheet of the present invention, a dry film is dried on one side of a polyphenylene sulfide (PPS) resin film (special PPS film) 12 having a thickness of 50 μm and containing a fine powder filler of aluminum nitride manufactured by an extrusion method. Using a laminating machine, a coating amount in a dry state of a polyurethane adhesive (base Takelac A515 / curing agent Takenate A50 = 10/1 solution) manufactured by Takeda Pharmaceutical Co., Ltd. with a solid content of 30% by weight is 4.0 g / m ^2. As a result, the anchor coat layer 13 was formed.

  This laminated body is mounted on a feed roll of a take-up vacuum deposition apparatus, and then this is fed out onto a coating drum, and silicon oxide is deposited under conditions of a processing temperature of 1000 ° C. and a cooling drum temperature of −40 ° C. during the deposition. A vapor deposition thin film 14 of silicon oxide having a thickness of 500 mm was formed on the anchor coat layer surface of the polyphenylene sulfide (PPS) resin film by a reactive vacuum vapor deposition method using a resistance heating method.

Similarly, the same adhesive as described above was applied to one of the two deposited thin film surfaces of the two sheets so as to be 4.0 g / m ² in a dry state, and each of the plastic film 11 and the plastic film 9 was applied. The vapor-deposited thin film surfaces were bonded together to produce the solar cell backsheet 4 of the present invention.

Subsequently, the solar cell element 3 connected in advance is placed on the front glass 1 on which a 400 μm-thick ethylene-vinyl acetate filler sheet is laid, and another filler sheet of the same material is placed thereon. Then, the solar battery back sheet 4 of the present invention is placed thereon, and the whole is hot-pressed at 150 ° C. for 10 minutes under reduced pressure to fuse and integrate the solar battery back sheet 4. The solar cell module having the configuration shown in FIG. 1 was prepared.
<Comparative Example 1>
As a plastic film 9 used for a solar battery back sheet, a dry lamination machine is used to apply a 50 μm thick biaxially stretched polyethylene terephthalate (PET) resin film 23 containing a fine powder white pigment of titanium oxide produced by an extrusion method. The coating amount in the dry state of a polyurethane adhesive (main agent Takelac A515 / curing agent Takenate A50 = 10/1 solution) with a solid content of 30% by weight made by Takeda Pharmaceutical Co., Ltd. is 4.0 g / m ^2. Then, an aluminum foil having a thickness of 20 μm is laminated thereon as the metal foil 21, and then the same adhesive as described above is applied to the aluminum foil surface so as to be 4.0 g / m ^{2 in a} dry state. 100 μm-thick biaxially oriented polyethylene terrestrial film containing fine white powder of titanium oxide, which is the same as plastic film 9 A tarate (PET) resin film 19 was bonded to prepare a solar cell back sheet.

Subsequently, the solar cell element 3 connected in advance is placed on the front glass 1 on which a 400 μm-thick ethylene-vinyl acetate filler sheet is laid, and another filler sheet of the same material is placed thereon. Then, the solar battery back sheet is placed thereon, and the whole is heat-pressed under reduced pressure at 150 ° C. for 10 minutes to fuse and integrate the solar battery back sheet, and the ends are fixed with an aluminum frame 8. A solar cell module having the following configuration was created.
<Comparative example 2>
As a plastic film 24 used for a solar battery back sheet, a dry lamination machine is used for solid content on one side of a 38 μm-thick polyvinyl fluoride (PVF) resin film containing a fine powder white pigment of titanium oxide produced by an extrusion method. 30% by weight of Takeda Pharmaceutical Co., Ltd. polyurethane adhesive (main product Takelac A515 / curing agent Takenate A50 = 10/1 solution) was applied so that the application amount in a dry state was 4.0 g / m ² . .

A biaxially stretched polyethylene terephthalate (PET) resin film 26 having a thickness of 50 μm is laminated thereon, and then the same adhesive as above is dried to 4.0 g / m ^{2 on the} PET film surface. The solar cell back sheet was produced by applying and bonding a 38 μm-thick polyvinyl fluoride (PVF) resin film 28 containing a fine powder white pigment of titanium oxide.

Subsequently, the solar cell element 3 connected in advance is placed on the front glass 1 on which a 400 μm-thick ethylene-vinyl acetate filler sheet is laid, and another filler sheet of the same material is placed thereon. Then, the solar battery back sheet is placed thereon, and the whole is heat-pressed under reduced pressure at 150 ° C. for 10 minutes to fuse and integrate the solar battery back sheet, and the ends are fixed with an aluminum frame 8. A solar cell module having the following configuration was created.
<Comparative Example 3>
As a plastic film 29 used for a solar battery backsheet, a solid content of 30 μm on one side of a polyethylene terephthalate (PET) resin film having a fine powdery white pigment of titanium oxide produced by an extrusion method and having a thickness of 30 μm. A polyurethane adhesive (main agent Takelac A515 / curing agent Takenate A50 = 10/1 solution) manufactured by Takeda Pharmaceutical Co., Ltd. by weight was applied so that the coating amount in a dry state was 4.0 g / m ² .

A film obtained by depositing silicon oxide 31 on the biaxially stretched polyethylene terephthalate (PET) resin film 33 having a thickness of 12 μm is bonded to the PET film surface through the anchor coat layer 32, and then the same adhesion as described above is applied to the PET film surface. The agent was applied in a dry state to 4.0 g / m ^2, and a 50 μm thick PET resin film 35 containing a fine powdered white pigment of titanium oxide was bonded to prepare a solar cell back sheet.

  Subsequently, the solar cell element 3 connected in advance is placed on the front glass 1 on which a 400 μm-thick ethylene-vinyl acetate filler sheet is laid, and another filler sheet of the same material is placed thereon. Then, the solar battery back sheet is placed thereon, and the whole is heat-pressed under reduced pressure at 150 ° C. for 10 minutes to fuse and integrate the solar battery back sheet, and the ends are fixed with an aluminum frame 8. A solar cell module having the following configuration was created.

  <Evaluation> The thermal conductivity in the thickness direction was measured by a steady comparison method based on ASTM E1570 using the solar battery backsheets prepared in Examples 1 and 2 and Comparative Examples 1 to 3.

<Evaluation> Using the solar cell modules prepared in Examples 1 and 2 and Comparative Examples 1 to 3, a battery characteristic test such as maximum output based on JIS-C8913 was carried out and measured.

Determination of barrier property and electrical insulation of laminate: Relative superiority / decision Thermal conductivity of laminate: 積 層 → 10 W / mK or more ○ → 1-10 W / mK × → less than 1 W / mK Battery element output judgment: ◎ → Output Less than 3% decrease ○ → Output decrease 3-5% × → Output decrease 5% or more From the evaluation results of Example 1 and Example 2, the number of lamination of the inorganic oxide vapor deposition layer has an effect of improving the barrier property, It has been clarified that the use of a special PPS film for the back sheet can improve the thermal conductivity and suppress the decrease in output as compared with the case of a normal plastic film.

From the evaluation results of Example 2 and Comparative Example 1, in the solar cell backsheet having the configuration using the polyphenylene sulfide (PPS) resin film containing the fine powder of aluminum nitride as the filler, compared with the case of the laminated sheet containing the aluminum foil. It has been clarified that the barrier property is the same level, the thermal conductivity is increased, and that the output of the solar cell element is further suppressed in the solar cell module produced by using it as a back sheet.

  From the above results, the solar cell backsheet of the present invention is excellent in heat resistance, weather resistance, gas barrier properties relating to water vapor, oxygen gas, etc., durability and other physical properties, and has good manufacturability and cost. A battery module can be obtained.

  In particular, a solar cell module that can effectively prevent a rise in temperature by dissipating heat generated inside the module to the outside while ensuring barrier properties, prevent deterioration of components due to a rise in temperature, and effectively suppress a drop in output Is now available.

It is composition cross-sectional explanatory drawing of an example of a solar cell module. It is composition cross-sectional explanatory drawing of an example of the solar cell backsheet of this invention. It is composition cross-sectional explanatory drawing of an example of the solar cell backsheet of this invention. It is composition cross-sectional explanatory drawing of an example of the solar cell backsheet of a comparative example. It is composition cross-sectional explanatory drawing of an example of the solar cell backsheet of a comparative example. It is composition cross-sectional explanatory drawing of an example of the solar cell backsheet of a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Front glass 2 ... Filler 3 ... Solar cell 4 ... Back sheet 5 ... Lead wire 6 ... Sealing agent 7 ... Terminal box 8 ... Aluminum frame 9 ... Special PPS100micrometer
DESCRIPTION OF SYMBOLS 10 ... Anchor layer 11 ... Inorganic oxide vapor deposition layer 12 ... Special PPS50micrometer
DESCRIPTION OF SYMBOLS 13 ... Anchor layer 14 ... Inorganic oxide vapor deposition layer 15 ... Adhesive layer 16 ... Inorganic oxide vapor deposition layer 17 ... Anchor layer 18 ... Special PPS50micrometer
19 ... White PET 100μm
20 ... Adhesive layer 21 ... Aluminum foil 20 μm
22 ... Adhesive layer 23 ... White PET 50μm
24 ... White PVF 38μm
25 ... Adhesive layer 26 ... PET 50μm
27 ... Adhesive layer 28 ... White PVF 38μm
29 ... White PET 50μm
30 ... Adhesive layer 31 ... Inorganic oxide vapor deposition layer 32 ... Anchor coat layer 33 ... PET 12 μm
34 ... Adhesive layer 35 ... White PET 50 μm

Claims (4)

  A solar cell back sheet, which is a sheet used for protecting the back surface of a solar cell module, and is a laminate in which a plastic film containing a heat conductive filler is laminated.   The solar cell backsheet according to claim 1, wherein a vapor-deposited thin film layer of an inorganic oxide is formed on at least one surface of a plastic film containing a thermally conductive filler.   The solar cell backsheet according to claim 1 or 2, wherein the thermally conductive filler is at least one of silicon oxide, aluminum oxide, boron nitride, silicon nitride, and aluminum nitride.   A solar cell module using the solar cell backsheet according to any one of claims 1 to 3 for back surface protection.