JP4639822B2 - Back protection sheet for solar cells - Google Patents

Description

  The present invention provides heat resistance, weather resistance, water resistance, moisture resistance, wind pressure resistance, drought resistance, chemical resistance, antifouling properties, light reflectivity, light diffusibility, etc. that can withstand harsh natural environments over a long period of time. It is related with the cheap back surface protection sheet for solar cells excellent in the various characteristics of this, and excellent in the reflectivity of incident light.

  In recent years, various efforts have been made to suppress carbon dioxide emissions while interest from various countries both inside and outside Japan has increased. It is said that the increase in the consumption of fossil fuels causes an increase in atmospheric carbon dioxide, the temperature of the earth rises due to the greenhouse effect, and is said to have a serious impact on the global environment. And while various energy alternatives to fossil fuels are being studied, solar cells, which are clean energy sources, are attracting attention, and expectations are increasing day by day.

  A solar cell constitutes the heart of a solar power generation system that directly converts sunlight energy into electricity, and is made of a semiconductor.

  Moreover, the structure does not use a single solar cell element as it is, but generally several to several tens of solar cell elements are wired in series or in parallel, and the elements are arranged for a long time (about 20 years). ), Various kinds of parsing for protection are performed and unitized.

  The unit incorporated in this package is called a solar cell module, and generally the surface that receives sunlight is covered with glass, and the gap is filled with a filler made of thermoplastic. The back surface is protected by a sheet 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. In particular, the back protective sheet is required to have a weather resistance and a low water vapor transmission rate. This is because if the filler is peeled off or discolored due to the permeation of moisture or the wiring is corroded, the output of the module itself may be affected.

(1) Prior art 1
As a back protection sheet for solar cells, heat resistant, weather resistant, wind pressure resistant, light resistant, moisture proof, and other required functions were laminated, and an inexpensive heat resistant and weather resistant plastic film made of polyester resin was laminated. A back surface protection sheet having a configuration (for example, see Patent Document 1) is known.

  As shown in FIG. 7, the back surface protection sheet 100 is 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. An inorganic oxide thin film layer 102 is applied to one surface of a weatherproof, lightproof, and moistureproof plastic film 101. Then, another heat resistance, weather resistance, light resistance, and moisture proof plastic film 101 is laminated on the surface of the thin film layer 102 via an adhesive layer 103.

(2) Prior art 2
Excellent strength and weather resistance, heat resistance, water resistance, light resistance, wind pressure resistance, rain resistance, chemical resistance, moisture resistance, antifouling, light reflectivity, light diffusibility, design, etc. A back surface protection sheet for solar cell modules (see, for example, Patent Document 2) that is excellent in various characteristics and is safer at lower cost is also known.

  As shown in FIG. 8, the back surface protective sheet 200 has a heat seal resin layer 104 laminated on the front side surface of the base film 105. The rear side surface is provided with an inorganic oxide vapor deposition film 106, and a heat-resistant polypropylene resin film 107 is laminated on the surface of the vapor deposition film 106. Further, a weather-resistant black outermost layer 108 is provided.

(3) Prior art 3
In addition, it has various functions such as heat resistance, weather resistance, moisture proof and other required functions, and is a laminated body composed of a low-priced heat resistance, weather resistance, water resistance, and light resistance plastic film made of polyester resin. The back surface protection sheet for solar cells (for example, refer patent document 3) is also known.

  This back surface protective sheet 300 has a heat resistance consisting 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, as shown in FIG. A weather-resistant, water-resistant, and light-resistant plastic film 109 is formed by laminating a front side surface and a back side surface of a metal foil 111 with an adhesive layer 110 interposed therebetween.

(4) Prior art 4
In addition, a back sheet for a solar cell cover material that is lightweight and has excellent water resistance and voltage resistance, is excellent in incident light reflectivity, is lightweight, inexpensive, and has excellent durability (for example, (See Patent Document 4).

  As shown in FIG. 10, this solar cell cover material backsheet 400 is resistant to hydrolysis through an adhesive layer 113 on one surface of a resin film 116 in which a metal film 115 is deposited on a base film 114. A functional resin film 117 is laminated. The other surface also has a structure composed of a two-layer to three-layer resin film laminate in which a white resin film 112 is laminated via an adhesive layer 113. The base film 114 is made of polyester film, the metal oxide 115 film is made of aluminum oxide, and the white pigment is made of titanium oxide.

Prior art documents are shown below.
JP 2002-134771 A (first page) JP2003-152212A (first page) JP 2002-134770 A (first page) JP 2002-10078 (first page)

(1) Prior Art 1 In Prior Art 1, since a metal foil such as an aluminum foil is not used for the back surface protection sheet, a solar cell element and aluminum produced when the protection sheet is damaged when a solar cell is manufactured. There is no adverse effect such as causing a short circuit with the foil or the like, resulting in a decrease in battery performance. However, there is a problem that incident light passes through the back surface protection sheet.

  Furthermore, since the member surface such as the roof in the rear side direction where the solar cell is installed is heated by permeation, there is a problem that the inside of the solar cell module is heated and the protection capability is lowered.

  Moreover, since incident light cannot be reflected and returned to a solar cell element, there exists a problem that power conversion efficiency is bad.

(2) Prior Art 2 Similar to Prior Art 1, a solar cell element produced by scratching a protective sheet when a solar cell is produced because a metal foil such as an aluminum foil is not used for the back surface protective sheet. There is no adverse effect such as a short circuit between the aluminum foil and the aluminum foil, and the battery performance is deteriorated. However, there is a problem that incident light passes through the back surface protection sheet. Furthermore, since the member surface such as the roof in the back side direction where the solar cell is installed is heated by permeation, there is a problem that the inside of the solar cell module is heated and the protection ability is lowered.

  Furthermore, since incident light cannot be reflected and returned to the solar cell element, there is a problem that power conversion efficiency is poor.

(3) Prior Art 3 A metal foil is sandwiched between weather-resistant plastic films. For this reason, the light which has entered the back surface protective sheet can be reflected and returned to the solar cell element to improve the power conversion efficiency. However, because metal foil is used, when manufacturing solar cells, the protective sheet is damaged, causing a short circuit between the solar cell element and aluminum foil, etc., and adversely affecting battery performance. There is. Moreover, since metal foil is used, there exists a problem that material cost is high and sales cost becomes high.

  In addition, because of the use of metal foil, etc., it has excellent strength, weather resistance, heat resistance, water resistance, moisture resistance, light resistance, chemical resistance, puncture resistance, impact resistance, and other robustness. Excellent in properties. Further, there are advantages such that the surface hardness is high, the surface is excellent in antifouling property to prevent the accumulation of dirt, dust and the like, and the protective ability is extremely high. However, there are problems that plasticity, lightness, light reflectivity, light diffusibility, designability and the like are lacking, and that workability or workability is inferior, and cost reduction cannot be achieved as described above.

(4) Prior Art 4 A white resin film in which an aluminum oxide film is provided on the back side of the resin film and titanium oxide is added to the front side is used without using a metal foil such as an aluminum foil on the back protective sheet. ing. For this reason, when manufacturing solar cells, the protective sheet is damaged, there is no adverse effect such as short circuit between the solar cell element and aluminum foil, etc. Conceivable.

  However, the white resin film used for the protective sheet is thin and the amount of titanium oxide to be added is limited in terms of physical properties. Therefore, it is impossible to provide a concealing force until all incident light is reflected. is there. For this reason, a part of the incident light is transmitted through the back surface protection sheet, and the member surface such as the roof in the back side direction where the solar cell is installed is heated, so the inside of the solar cell module becomes hot, There is a problem that the protection ability decreases.

  This invention is made | formed in view of the said conventional problem, and it aims at providing the back surface protection sheet for solar cells as follows.

That is, the first object of the present invention is excellent in strength, weather resistance, heat resistance, moisture resistance, water resistance, light resistance, chemical resistance, puncture resistance, impact resistance, and other various fastness properties. Furthermore, it has a high surface hardness and excellent antifouling properties that prevent accumulation of dirt, dust, and the like. And the back surface for solar cells that has high protective ability, is excellent in plasticity, lightness, light reflectivity, light diffusibility, design, etc., and has good workability or workability, etc. It is to provide a protective sheet.

  In addition, the second object of the present invention is that when a solar cell is manufactured, the protective sheet is damaged, a short circuit is caused between the solar cell element and the aluminum foil, and the battery performance is deteriorated. It is providing the back surface protection sheet for solar cells which does not have.

  The third object of the present invention is to provide a solar cell back surface protection sheet with good power conversion efficiency, in which incident light is substantially reflected and returned to the solar cell element.

  Moreover, the 4th objective of this invention is to provide the back surface protection sheet for solar cells with little temperature rise in a solar cell module, and a large protection capability.

  The fifth object of the present invention is to provide a back surface protection sheet for solar cells that can be molded and processed by a general-purpose method and can be mass-produced.

In order to solve the above problems, first, the invention according to claim 1 of the present invention is:
Vapor deposition formed with inorganic oxide of silicon oxide or aluminum oxide on the vapor deposition substrate film surface of the vapor deposition film through the adhesive layer containing white pigment, provided with a base film in the upper direction where the solar cell element is provided Laminated with a film layer, and further, the vapor-deposited base film is laminated with a back base film through an adhesive layer containing a white pigment,
The back surface protection sheet for solar cells, wherein the white pigment content of the white pigment-containing adhesive layer is 20 to 40% .

Next, the invention according to claim 2 of the present invention is
2. The solar cell back surface protective sheet according to claim 1, wherein the adhesive of the white pigment-containing adhesive layer is made of a two-component curable polyurethane resin adhesive .

  The back surface protection sheet for solar cells of the present invention is provided with an inorganic vapor deposition layer, the resin film, and other heat resistance, weather resistance, water resistance, moisture resistance, moisture resistance, antifouling property, light reflectivity, and other properties. It is a laminate having a structure in which a base film or the like excellent in the structure is laminated. For this reason, it excels in heat resistance, weather resistance, water resistance, moisture resistance, wind pressure resistance, light resistance, rain resistance, chemical resistance, moisture resistance, antifouling property, light reflectivity, etc., and when manufacturing solar cells In addition, there is no adverse effect on the battery performance due to a short circuit caused by damage to the protective sheet, and there is no deterioration of various functions for a long period (about 20 years), and it can be used outdoors.

  Moreover, since a white ink layer or the like is provided in addition to the vapor deposition film layer such as aluminum oxide or silicon oxide, incident light can be reflected and returned to the solar cell element to improve power conversion efficiency.

  Furthermore, since the incident light can be reflected by the white ink layer, the heating in the solar cell module is reduced.

  Furthermore, the back surface protection sheet for solar cells can be molded and processed by a general-purpose method, and can be mass-produced at a low price.

  The back surface protection sheet for solar cells of this invention is demonstrated in detail, referring drawings below along embodiment. 1 to 6 show an embodiment of the present invention.

  1 to 5 are schematic cross-sectional views illustrating the layer structure of the back surface protective sheet for solar cell according to the present invention.

First, as shown in FIG. 1, the back surface protection sheet 1 for solar cells according to one reference example of the present invention is provided with a base film 6 from an upper direction where solar cell elements are provided. Then, the white ink layer 11 and the adhesive layer 7 on the surface of the vapor deposition film layer 8 of an inorganic oxide such as silicon oxide or aluminum oxide excellent in water vapor barrier property, oxygen barrier property, etc. are formed on the vapor deposition base film 9 of the vapor deposition film 10. It is laminated through. Further, the vapor deposition base film 9 is laminated with the back base film 14 via the adhesive layer 7.

  As the substrate film 6 constituting the solar cell back surface protection sheet (shown in FIGS. 1 to 5) according to the present invention, basically, another film or sheet or the white ink layer 11 is used. It is excellent in close adhesiveness with the like, and can be held well without impairing the properties of those layers.

  Further, those having excellent strength and excellent fastness such as weather resistance, heat resistance, water resistance, light resistance, wind pressure resistance, yield resistance, chemical resistance and the like are preferable. In particular, it has excellent moisture resistance to prevent intrusion of moisture, oxygen, etc., has high surface hardness, and excellent antifouling property to prevent the accumulation of dirt and dust on the surface. Various resin films or sheets having characteristics such as high ability can be used.

  Examples of the various resin films or sheets include polyethylene resins, polypropylene resins, cyclic polyolefin resins, polystyrene resins, acrylonitrile-styrene copolymers (AS resins), acrylonitrile-butadiene-styrene copolymers. Polymer (ABS resin), polyvinyl chloride resin, fluorine resin, poly (meth) acrylic resin, polycarbonate resin, polyester resin such as polyethylene terephthalate or polyethylene naphthalate, Polyamide resins such as various nylons, polyimide resins, polyamideimide resins, polyaryl phthalate resins, silicone resins, polysulfone resins, polyphenylene sulfide resins, polyethersulfone resins, polyurethane resins , Acetal resin, Carlo - scan resins, other film or sheet of various resins - can be used and.

In the present invention, among the resin films or sheets, fluorine resin, cyclic polyolefin resin, polycarbonate resin, poly (meth) acrylic resin, polyamide resin, or It is preferable to use a polyester resin film or sheet.

  More preferably, among the polyester resins, excellent properties such as mechanical properties, chemical properties, physical properties, etc., specifically, weather resistance, heat resistance, water resistance, light resistance, moisture resistance, It is desirable to use a film or sheet of polyethylene terephthalate resin that has stain resistance, chemical resistance, durability, protective functionality, etc., and is excellent in other properties.

  In the present invention, the film or sheet used as the base film 6 has a film thickness of about 12 to 300 μm, more preferably about 12 to 200 μm.

  Next, the vapor deposition substrate film 9 provided with the vapor deposition film layer 8 basically withstands the vapor deposition conditions when forming the inorganic oxide vapor deposition film layer 8 and the like, and the inorganic oxidation film. What is excellent in the close adhesiveness with the vapor deposition film etc. of a thing and can hold | maintain favorably without impairing the characteristic of those films | membranes is preferable.

  In addition, it has excellent strength and excellent fastness such as weather resistance, heat resistance, water resistance, light resistance, wind pressure resistance, yield resistance, chemical resistance, etc., especially moisture prevention that prevents intrusion of moisture, oxygen, etc. Various properties that have excellent properties, such as high surface hardness, excellent antifouling properties that prevent accumulation of dirt, dust, etc. on the surface, excellent durability, and high protective ability. Resin films or sheets can be used.

  Examples of the various resin films or sheets include polyethylene resins, polypropylene resins, cyclic polyolefin resins, polystyrene resins, acrylonitrile-styrene copolymers (AS resins), acrylonitrile-butadiene-styrene copolymers. Polymer (ABS resin), polyvinyl chloride resin, fluorine resin, poly (meth) acrylic resin, polycarbonate resin, polyester resin such as polyethylene terephthalate or polyethylene naphthalate, Polyamide resins such as various nylons, polyimide resins, polyamideimide resins, polyaryl phthalate resins, silicone resins, polysulfone resins, polyphenylene sulfide resins, polyethersulfone resins, polyurethane resins , Acetal resin, Carlo - scan resins, other film or sheet of various resins - can be used and.

  In the present invention, among the resin films or sheets, fluorine resin, cyclic polyolefin resin, polycarbonate resin, poly (meth) acrylic resin, polyamide resin, or It is preferable to use a polyester resin film or sheet.

  And by using the resin film or sheet as described above, it has excellent properties such as mechanical properties, chemical properties, physical properties, specifically, weather resistance, heat resistance, It is a back surface protection sheet constituting a solar cell utilizing water resistance, light resistance, moisture resistance, contamination resistance, chemical resistance, and other characteristics. Accordingly, there are advantages such as durability, protective functionality, etc., lightness from its flexibility, mechanical properties, chemical properties, etc., and excellent molding and workability.

The various resin films or sheets may be, for example, one or more of the above-mentioned various resins, extrusion method, cast molding method, T-die method, inflation method, and other film forming methods. A method of forming a film of each of the above-mentioned various resins by using a chemical conversion method, a method of forming a multi-layer coextrusion film using two or more of various resins, or two or more of resins Various resin films or sheets are produced by a method of mixing and forming a film before use and film formation. In the present invention, the film thickness of various resin films or sheets is preferably about 12 to 300 μm, more preferably about 12 to 200 μm.

  When one or more of the above-mentioned various resins are used and the film is formed, for example, film processability, heat resistance, light resistance, weather resistance, mechanical properties, dimensional stability, antioxidation, slip Various plastic compounding agents, additives and the like can be added for the purpose of improving and modifying properties, mold release properties, flame retardancy, antifungal properties, electrical properties, and the like. And as the addition amount, it can be arbitrarily added from a very small amount to several tens of percent according to the purpose.

  Examples of the additive include a lubricant, a crosslinking agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a filler, a lubricant, a reinforcing fiber, a reinforcing agent, an antistatic agent, a flame retardant, a flame retardant, and a foaming agent. Antifungal agents, pigments, etc. can be used. Furthermore, a modifying resin or the like can be used. In the present invention, among the additives described above, it is particularly possible to use various resin films or sheets obtained by kneading and processing an ultraviolet absorber, a light stabilizer, or an antioxidant. preferable.

  As the UV absorber, harmful ultraviolet rays in sunlight are absorbed and converted into innocuous heat energy in the molecule to prevent the activation of photo-degraded active species in the polymer. For example, benzophenone, benzotriazole, saltylate, acrylonitrile, metal complex, ultrafine titanium oxide (particle diameter, 0.01 to 0.06 μm) or ultrafine zinc oxide ( One or more inorganic ultraviolet absorbers such as 0.01 to 0.04 μm) can be used.

  As the light stabilizer, for example, hindered amine compounds, hindered-topiperidine compounds, and other one or more can be used. Further, the antioxidant is to prevent oxidative degradation caused by light or heat of the polymer, for example, phenol, amine, sulfur, phosphoric acid, and other antioxidants. Agents can be used.

  Moreover, in this invention, the vapor deposition film layer 8 provided in the vapor deposition base film 9 surface may be the surface of a solar cell direction of a solar cell element, or the surface of the opposite direction, and is provided in any one side. And when applying the vapor deposition film layer 8 etc. of an inorganic oxide to the vapor deposition substrate film 9, in order to improve the tight adhesion and the like, a desired surface is shown in advance, although not shown in the drawing as necessary. A treatment layer can be provided.

  Examples of the surface treatment layer include pretreatments such as corona discharge treatment, ozone treatment, plasma treatment using oxygen gas or nitrogen gas, glow discharge treatment, oxidation treatment using chemicals, and the like. For example, a corona-treated surface, an ozone-treated surface, a plasma-treated surface, an oxidation-treated surface, other surface-treated surfaces, and the like can be provided.

  The surface pretreatment can also be performed in a separate process. For example, in the case of surface pretreatment by plasma treatment, glow discharge treatment, or the like, pretreatment by inline treatment can be performed as pretreatment for forming the inorganic oxide vapor deposition film layer 8 or the like. Further, there is an advantage that the manufacturing cost is reduced.

  In addition to the above method for improving the tight adhesion, for example, a primer coat agent layer, an undercoat agent layer, an anchor coat agent layer, An adhesive layer or a deposition anchor coating agent layer may be arbitrarily formed to form a surface treatment layer.

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

  Further, the inorganic oxide vapor deposition film layer 8 applied to either of the front and back surfaces of the vapor deposition substrate film 9 may be formed by, for example, physical vapor deposition, chemical vapor deposition, or both. In combination, it can be produced by forming a single-layer film composed of one inorganic oxide vapor-deposited film layer, or a multilayer film or composite film composed of two or more layers.

  Examples of the inorganic oxide vapor-deposited film formed by the physical vapor deposition method include physical vapor deposition methods (physical vapor deposition methods) such as vacuum vapor deposition, sputtering, ion plating, and ion cluster beam method. , PVD method), an inorganic oxide vapor deposition film can be formed. In the present invention, a metal oxide such as aluminum oxide or silicon oxide is used as a raw material, and this is heated and evaporated on the surface of the vapor deposition substrate film 9, or a metal or metal oxide is used as a raw material. The vapor deposition film layer 8 is formed using an oxidation reaction vapor deposition method in which oxygen is introduced to oxidize and vapor deposition is performed on the surface of the vapor deposition substrate film 9, and a plasma-assisted oxidation reaction vapor deposition method in which the oxidation reaction is supported by plasma. be able to.

  As the heating method for the vapor deposition material, for example, a resistance heating method, a high frequency induction heating method, an electron beam heating method (EB), or the like can be used.

  The film thickness of the inorganic oxide vapor-deposited film layer varies depending on the type of metal or metal oxide used, but is arbitrarily selected within the range of, for example, 5 to 400 nm, preferably 10 to 100 nm. It is desirable to form it.

  Examples of the vapor-deposited film of the inorganic oxide by the chemical vapor deposition method include chemical vapor deposition methods such as plasma chemical vapor deposition method, thermal chemical vapor deposition method, and photochemical vapor deposition method (Chemical Vapor Deposition method). A vapor deposition film of an inorganic oxide can be formed using a method, a CVD method, or the like. Specifically, a vapor deposition monomer gas such as an organosilicon compound is used as a raw material on one surface of the vapor deposition base film 9, and an inert gas such as argon gas or helium gas is used as a carrier gas.

  Furthermore, a vapor deposition film of an inorganic oxide such as silicon oxide can be formed by using a low temperature plasma chemical vapor deposition method using an oxygen gas or the like as an oxygen supply gas and using a low temperature plasma generator or the like. In the above, as a low temperature plasma generator, generators, such as high frequency plasma, pulse wave plasma, and microwave plasma, can be used, for example. In order to obtain highly active and stable plasma, it is desirable to use a high frequency plasma generator.

  In addition, the formation of the inorganic oxide vapor-deposited film can be achieved by forming an inorganic oxide vapor-deposited film in which different kinds of materials are mixed using one kind or a mixture of two or more kinds of metals or metal oxides. .

  As the inorganic oxide vapor deposition film, any thin film in which a metal oxide is vapor deposited can be used. For example, silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca ), Potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), yttrium (Y), etc. Can be used.

Moreover, as a preferable thing, the vapor deposition film | membrane of metal oxides, such as silicon (Si) and aluminum (Al), can be mentioned. In the present invention, aluminum oxide or silicon oxide is used.

  Next, as an adhesive for forming the adhesive layer 7, for example, a two-component curable polyurethane resin (alkit resin, acrylic resin, polyvinyl alcohol, or the like) usually composed of a solvent solution of a polyol component and an isocyanate component is used. A hydroxyl group (—OH), a resin cured by an isocyanate group (—NCO) reaction of an isocyanate resin as a curing agent (crosslinking agent), and the like are used.

  The polyurethane resin-based adhesive is easy to react with active hydrogen contained in many functional groups, and has good solubility and wettability with the adherend. Therefore, it is high in various plastic film or sheet combinations. Shows adhesion.

  In addition, as an adhesive, for example, a two-component curable polyurethane resin-based adhesive is used by mixing so as to have a preset ratio, and after applying to one or both of two surfaces to be bonded, both are used. After applying and pressing, or after coating and once drying, both are overlapped, heated and pressed to adhere.

  In applying the adhesive, a coating machine such as a roll coater or a gravure roll coater is usually used.

The coating amount is formed in the range of ² to 20 g / m ^{2 in} terms of solid content. Lamination is performed using a normal dry laminator or an extrusion coater.

  Next, the white ink layer 11 for reflecting incident light is formed on the entire surface by white printing with white ink. As the solid printing means, any known roll coating or gravure roll coating may be used, but gravure printing can be suitably used. And incident light can be reflected more by printing once or twice.

  Examples of the white pigment used in the white ink include titanium oxide and / or barium sulfate. In addition, inorganic fillers such as silicon oxide, aluminum oxide, magnesium oxide, calcium carbonate, kaolin and talc, and organic fillers such as cross-linked polystyrene resin, cross-linked acrylic resin, urea resin and melamine resin should be included as required. Can do.

  Next, as the back surface base film 14 constituting the back surface protection sheet for solar cell according to the present invention (shown in FIGS. 1 to 5), basically, another film or sheet or ink layer is used. It is desirable that the film has excellent close adhesion with the film and can be held well without impairing the characteristics of the film.

  Further, those having excellent strength and excellent fastness such as weather resistance, heat resistance, water resistance, light resistance, wind pressure resistance, yield resistance and chemical resistance are preferable. In particular, it has excellent moisture resistance to prevent intrusion of moisture, oxygen, etc., has high surface hardness, and excellent antifouling property to prevent the accumulation of dirt and dust on the surface. Various resin films or sheets having characteristics such as high ability can be used.

Examples of the various resin films or sheets include polyethylene resins, polypropylene resins, cyclic polyolefin resins, polystyrene resins, acrylonitrile-styrene copolymers (AS resins), and acrylonitrile-butadiene-styrene copolymers. Polymer (ABS resin), polyvinyl chloride resin, fluorine resin, poly (meth) acrylic resin, polycarbonate resin, polyester resin such as polyethylene terephthalate or polyethylene naphthalate, Polyamide resins such as various nylons, polyimide resins, polyamideimide resins, polyaryl phthalate resins, silicone resins, polysulfone resins, polyphenylene sulfide resins, polyethersulfone resins, polyurethane resins , Acetal resin, Carlo - scan resin, other various resin films or sheets - may be used and.

  In the present invention, among the resin films or sheets, fluorine resin, cyclic polyolefin resin, polycarbonate resin, poly (meth) acrylic resin, polyamide resin, or It is preferable to use a polyester resin film or sheet.

  Among the polyester-based resins described above, excellent properties such as mechanical properties, chemical properties, and physical properties, specifically, weather resistance, heat resistance, water resistance, light resistance, moisture resistance, and stain resistance. It is desirable to use a film or sheet of polyethylene terephthalate resin that has chemical resistance, durability, protective functionality, etc. and is excellent in other properties.

  Furthermore, in the present invention, the film or sheet used as the back substrate film 14 has a film thickness of about 12 to 300 μm, more preferably about 12 to 200 μm.

Next, FIG. 2 is a schematic sectional view showing the outline of the layer structure of another reference example of the back surface protection sheet for solar cells.

  As shown in FIG. 2, the back surface protection sheet 2 for solar cells is provided with a base film 6 in which a white ink layer 11 is formed on the back side surface from the upper direction where the solar cell elements are provided. And it is laminated | stacked with the white ink layer 11 currently formed in the vapor deposition film layer 8 surface of the vapor deposition film 10 via the contact bonding layer 7. FIG. Further, the vapor deposition base film 9 of the vapor deposition film 10 is laminated with the back surface base film 14 via the adhesive layer 7. The white ink layer 11 is provided to reflect incident light more. Further, the vapor deposition film 10 has a vapor deposition substrate film 9 on which a vapor deposition film layer 8 of an inorganic oxide such as silicon oxide or aluminum oxide is formed.

  Since the white ink layer 11 is provided on the back side surface of the base film 6 and the top surface of the vapor deposition film layer 8 of the vapor deposition base film 9, when the white ink layer 11 is used as a back surface protection sheet of a solar cell, incident light is It can be reflected and returned to the solar cell element to improve the power conversion efficiency. Moreover, since incident light is reflected, the heating in a solar cell module is reduced, and the deterioration of the member used is reduced.

  The white ink layer 11 provided on the back side surface of the base film 6 is applied to the entire back side surface of the base film 6 by solid printing with white ink in the same manner as the white ink layer 11 provided on the vapor deposition film 10. Is formed. Further, as the solid printing means, any known roll coating or gravure roll coating may be used, but gravure printing can be preferably used. Further, by performing printing once or twice, the concealing power becomes strong and incident light can be reflected more.

  Examples of the white pigment used in the white ink include titanium oxide and / or barium sulfate. In addition to this, inorganic fillers such as silicon oxide, aluminum oxide, magnesium oxide, calcium carbonate, kaolin and talc, and organic fillers such as cross-linked polystyrene resin, cross-linked acrylic resin, urea resin and melamine resin are included as necessary. can do.

  As the substrate film 6, the vapor deposition substrate film 9, the back substrate film 14 and the like, those similar to those shown in FIG. 1 can be used. Moreover, the vapor deposition film layer 8 provided on the upper side surface of the vapor deposition substrate film 9 may be a surface in the solar cell element direction of the solar cell or a surface in the opposite direction, and is provided on any one side surface. And when applying the inorganic oxide vapor-deposited film layer 8 or the like to the vapor-deposited base film 9, a desired surface treatment layer (not shown in the figure) is preliminarily provided as necessary in order to improve the tight adhesion and the like. ) Can be provided.

  Further, the adhesive layer 7 is preferably an adhesive similar to that shown in FIG. For example, as a two-component curable polyurethane resin comprising a polyol component and an isocyanate component, usually each solvent solution (hydroxyl group (—OH) such as Alkit resin, acrylic resin or polyvinyl alcohol, and a curing agent (crosslinking agent)) An adhesive resin that is cured by an isocyanate group (—NCO) reaction of the isocyanate resin of FIG. Then, use a two-component curable polyurethane resin adhesive, etc., in such a way that it is mixed in a preset ratio, apply it to one or both of the two surfaces to be bonded, and then press the two layers together Alternatively, after coating and once drying, the two are superposed and heated and pressed to adhere.

Next, FIG. 3 is a schematic cross-sectional view showing an outline of another reference example of the layer configuration of the solar cell back surface protective sheet.

  As shown in FIG. 3, the back surface protection sheet 3 for solar cells is a base film 6 in which a white ink layer 11 for reflecting incident light more is applied to both sides from the upper direction where the solar cell elements are provided. The vapor deposition film layer 8 of the vapor deposition film 10 is laminated via the adhesive layer 7. Further, the vapor deposition base film 9 and the back base film 14 are laminated via the adhesive layer 7. The vapor deposition film layer 8 of the vapor deposition film 10 is formed on the vapor deposition base film 9 with an inorganic oxide such as silicon oxide or aluminum oxide.

  Since the white ink layer 11 is provided on both side surfaces of the base film 6, when used as a back surface protection sheet for a solar cell, the incident light is reflected and a solar cell element (shown in the figure). However, the power conversion efficiency can be improved. Moreover, since incident light is reflected, the heating in a solar cell module is reduced, and the deterioration of the member used is reduced.

  The white ink layer 11 provided on both side surfaces of the substrate film 6 is solidly printed with white ink in the same manner as the white ink layer 11 applied to the vapor deposition film 2 of FIG. 1 or FIG. 6 is formed on the entire surface on both sides. As the solid printing means, any known roll coating or gravure roll coating or dipping may be used, but gravure printing can be preferably used. Then, by performing printing once or twice, the concealing power becomes strong and incident light can be reflected more.

  Examples of the white pigment used in the white ink include titanium oxide and / or barium sulfate. In addition to this, inorganic fillers such as silicon oxide, aluminum oxide, magnesium oxide, calcium carbonate, kaolin and talc, and organic fillers such as cross-linked polystyrene resin, cross-linked acrylic resin, urea resin and melamine resin are included as necessary. can do.

  As the substrate film 6, the vapor deposition substrate film 8, the back substrate film 14 and the like, those similar to those shown in FIG. 1 or 2 can be used. Further, the vapor deposition film layer 8 provided on the surface of the vapor deposition substrate film 9 may be a surface in the solar cell element direction of the solar cell or a surface in the opposite direction, and is provided on any one side surface. In addition, when applying the inorganic oxide vapor deposition film layer 8 or the like to the vapor deposition substrate film 9, a desired surface treatment layer (shown in the figure) is preliminarily provided as necessary in order to improve the tight adhesion and the like. Not).

  Next, FIG. 4 is a schematic cross-sectional view showing an outline of a layer configuration of another example of the back surface protective sheet for solar cell.

As shown in FIG. 4, the back surface protection sheet 4 for solar cells is provided with a base film 6 in the upper direction where the solar cell elements are provided. And it is laminated | stacked with the vapor deposition film layer 8 formed with inorganic oxides, such as a silicon oxide or aluminum oxide, on the vapor deposition base film 9 surface of the vapor deposition film 10 through the adhesion layer 12 containing a white pigment. Further, the vapor deposition base film 9 is laminated with the back base film 14 via the white pigment-containing adhesive layer 12 .

  The white pigment-containing adhesive layer 12 is formed on the back surface of the base film 6 and the directional surface on which the solar cell elements of the back base film 14 are provided. For this reason, when it is used as a back surface protection sheet of a solar cell, incident light is reflected and returned to the solar cell element (not shown in the figure), thereby improving the power conversion efficiency. Moreover, since incident light is reflected, the heating in a solar cell module is reduced, and the deterioration of the member used is reduced.

  Examples of the adhesive for the white pigment-containing adhesive layer 12 include, for example, a two-component curable polyurethane resin composed of a solvent solution of a polyol component and an isocyanate component (alkit resin, acrylic resin, or polyvinyl alcohol). (-OH) and a white pigment, for example, titanium oxide and / or barium sulfate, are added to the adhesive (resin that is cured by an isocyanate group (-NCO) reaction of an isocyanate resin as a curing agent (crosslinking agent)). Yes. In addition, inorganic fillers such as silicon oxide, aluminum oxide, magnesium oxide, calcium carbonate, kaolin, and talc, and organic fillers such as crosslinked polystyrene resin, crosslinked acrylic resin, urea resin, and melamine resin are added as necessary. You can also

  Although it is desirable that the content of the white pigment is large, the adhesive strength is lowered. Therefore, it is usually 20 to 40%, preferably about 30 to 35%.

  As the substrate film 6, the vapor deposition substrate film 9, the back substrate film 14, and the like, the same ones as shown in FIGS. 1 to 3 can be used. Further, the vapor deposition film layer 8 provided on the surface of the vapor deposition substrate film 9 may be a solar cell element direction surface or an opposite direction surface of the solar cell, and is provided on any one side surface. Then, when applying the inorganic oxide vapor-deposited film layer 8 or the like to the vapor-deposited base film 9, a desired surface treatment layer (shown in the figure) is preliminarily provided as necessary in order to improve the tight adhesion and the like. Not)).

Next, FIG. 5 is a schematic cross-sectional view showing an outline of another reference example of the layer structure of the back surface protection sheet for solar cells.

  As shown in FIG. 5, the back surface protection sheet 5 for solar cells is provided with a white base film 13 in which a white ink layer is formed in the upper direction where the solar cell elements are provided. And the vapor deposition film 10 which provided the vapor deposition film layer 8 of inorganic oxides, such as a silicon oxide or aluminum oxide, on the back side surface of the vapor deposition base film 9 is laminated | stacked through the contact bonding layer 7. FIG. Furthermore, the vapor deposition film layer 8 is laminated | stacked with the back surface base film 14 through the adhesive layer 7 containing a white pigment.

  The white base film 13 is basically excellent in close adhesion with other films or sheets or the white ink layer 11 and can be well maintained without impairing the characteristics of the films. What can be preferred.

Moreover, it is excellent in strength and excellent in various fastness properties such as weather resistance, heat resistance, water resistance, light resistance, wind pressure resistance, yield resistance, and chemical resistance. In particular, it has excellent moisture resistance to prevent the intrusion of moisture, oxygen, etc., has high surface hardness, and excellent antifouling property to prevent the accumulation of dirt, dust, etc. on the surface. White films or white sheets of various resins having characteristics such as high ability can be used.

  Examples of the white film or white sheet kneaded by adding a white pigment to various resins include, for example, polyethylene resins, polypropylene resins, cyclic polyolefin resins, polystyrene resins, acrylonitrile-styrene copolymer Polymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyvinyl chloride resin, fluorine resin, poly (meth) acrylic resin, polycarbonate resin, polyethylene terephthalate Or polyester resins such as polyethylene naphthalate, polyamide resins such as various nylons, polyimide resins, polyamideimide resins, polyaryl phthalate resins, silicone resins, polysulfone resins, polyphenylene sulfide Resin, polyethersulfone resin, polyester Urethane resins, acetals - Le resins, cellulose - scan resins, other, white film or white various resin - can be used and.

  Further, in the present invention, among the white film or white sheet kneaded by adding a white pigment to the resin, a fluorine resin, a cyclic polyolefin resin, a polycarbonate resin, a poly ( It is preferable to use a white film or a white sheet in which a white pigment is added and kneaded to a (meth) acrylic resin, a polyamide resin, or a polyester resin.

  Among the polyester-based resins, excellent properties such as mechanical properties, chemical properties, and physical properties, specifically, weather resistance, heat resistance, water resistance, light resistance, moisture resistance, and stain resistance Use a white film or white sheet kneaded by adding a white pigment to polyethylene terephthalate resin, which has chemical resistance, durability, protective functionality, etc., and other excellent properties. Is desirable.

  The white pigment added to the various resins is, for example, titanium oxide and / or barium sulfate. In addition, inorganic fillers such as silicon oxide, aluminum oxide, magnesium oxide, calcium carbonate, kaolin and talc, and organic fillers such as cross-linked polystyrene resin, cross-linked acrylic resin, urea resin and melamine resin are appropriately used as necessary. Used.

  In addition, a white film or a white sheet has a white pigment kneaded in various resins, and has a whiteness of 80% or more and an opacity of 80% or more.

  The white ink layer 11, the adhesive layer 7, the vapor deposition base film 9 or the back base film 14 can be the same as those shown in FIGS. Moreover, the vapor deposition film layer 8 provided on the back side surface of the vapor deposition substrate film 9 may be the module direction surface or the opposite direction surface of the solar cell, and is provided on any one side surface. Then, when applying the inorganic oxide vapor deposition film layer 8 or the like to the vapor deposition substrate film 9, in order to improve the tight adhesion, etc., as required, a desired surface treatment is performed in advance. A layer can be provided.

  When the white base film 13 and the white ink layer 11 are formed, the solar cell element (not shown in the figure) reflects incident light when used as a back surface protection sheet for a solar cell. ) To improve the power conversion efficiency. Moreover, the heating in a solar cell module is reduced, and deterioration of the member currently used decreases.

  Next, FIG. 6 is a schematic cross-sectional view showing an outline of a layer configuration of an embodiment of the solar cell 15 manufactured using the solar cell back surface protective sheet 1 of the present invention shown in FIG.

As shown in FIG. 6, the solar cell in which the solar cell back surface protective sheet 1 of the present invention is used is usually the solar cell surface protective sheet 16, the filler layer 17, and the solar cell as a photovoltaic element. The battery element 18, the filler layer 19, and the solar cell back surface protective sheet 1 of the present invention are sequentially laminated with the surface of the extruded resin layer 20 made of the resin composition facing each other. Next, they are manufactured by integral molding using a molding method such as a lamination method in which these are vacuum-sucked and thermocompression bonded. And the back surface protection sheet for solar cells (shown in FIGS. 2 to 5) of another embodiment of the present invention is also used as a back surface protection film for solar cells when manufacturing a solar cell as shown in FIG.

  The solar cell back surface protective sheet of the present invention is an excellent invention that can be used in a wide range of fields, such as roofing members such as poultry houses and cowsheds in summer and automobile covers, as well as being excellent as a back surface protective sheet for solar cells.

It is a schematic sectional drawing which shows the outline of the layer structure of the one reference example of the back surface protection sheet for solar cells of this invention. It is a schematic sectional drawing which shows the outline of the layer structure of the other reference example of the back surface protection sheet for solar cells of this invention. It is a schematic sectional drawing which shows the outline of the layer structure of the other reference example of the back surface protection sheet for solar cells of this invention. It is a schematic sectional drawing which shows the outline of the layer structure of other one Example of the back surface protection sheet for solar cells of this invention. It is a schematic sectional drawing which shows the outline of the layer structure of the other reference example of the back surface protection sheet for solar cells of this invention. It is a schematic sectional drawing which shows the outline of the layer structure of one Example of the solar cell manufactured using the back surface protection sheet for solar cells of this invention. It is a schematic sectional drawing which shows the outline of the layer structure of the back surface protection sheet for solar cells used conventionally. It is a schematic sectional drawing which shows the outline of the layer structure of the back surface protection sheet for solar cells used conventionally. It is a schematic sectional drawing which shows the outline of the layer structure of the back surface protection sheet for solar cells used conventionally. It is a schematic sectional drawing which shows the outline of the layer structure of the back surface protection sheet for solar cells used conventionally.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Back surface protection sheet for solar cells 2 ... Back surface protection sheet for solar cells 3 ... Back surface protection sheet for solar cells 4 ... Back surface protection sheet for solar cells 5 ... Back surface protection sheet for solar cells 6 ... Base film 7 ... Adhesive layer 8 Deposition film layer 9 Deposition substrate film 10 Deposition film 11 White ink layer 12 White pigmented adhesive 13 White substrate film 14 Back substrate film 15 Solar cell 16 Surface protection sheet for solar cell DESCRIPTION OF SYMBOLS 17 ... Filler layer 18 ... Solar cell element 19 ... Filler layer 20 ... Extruded resin layer

Claims (2)

Laminating a vapor deposition film layer formed of an inorganic oxide of silicon oxide or aluminum oxide on the surface of the vapor deposition substrate film of the vapor deposition film through an adhesive layer containing a white pigment on the base film,
Furthermore, the vapor-deposited base film is a back protective sheet for solar cells laminated with a back base film through an adhesive layer containing a white pigment,
The back surface protection sheet for solar cells, wherein the white pigment content of the white pigment-containing adhesive layer is 20 to 40% . The back surface protection sheet for solar cells according to claim 1, wherein the adhesive for the white pigment-containing adhesive layer is made of a two-component curable polyurethane resin adhesive .

Images