Adhesive sealing film and photovoltaic assembly

Abstract

The present invention provides a sealing adhesive film and a photovoltaic assembly. The sealing adhesive film includes a high infrared transmittance adhesive film layer and a high infrared reflectance adhesive film layer laminated on the high infrared transmittance adhesive film layer, the high infrared transmittance adhesive film layer has a transmittance of more than 55% for light in the wavelength range of 700-1100 nm and a transmittance of less than 2% for light in the wavelength range of 400-700 nm, and the high infrared reflectance adhesive film layer has a reflectance of more than 75% for light in the wavelength range of 700-1100 nm. When the sealing adhesive film is used as the sealing adhesive film on the back surface of the cell sheet, it can not only realize the black appearance of the photovoltaic module and reduce light pollution, but also maximize the use of sunlight and improve the overall photoelectric conversion efficiency of the photovoltaic module, thereby improving the efficiency of the solar cell and extending its life. Furthermore, when the sealing adhesive film is used for BIPV building integration, it can achieve both the aesthetic appearance of the building and the efficiency of the photovoltaic module.

Description

Technical Field

[0001] This application is based on a Chinese application with Chinese Patent Application No. 202111593985.X and a filing date of December 24, 2021, claims the priority of the said application, and the disclosure content of the said Chinese application is incorporated into this application again as a whole.

[0002] The present invention relates to the technical field of photovoltaic assemblies, and specifically to an adhesive film for sealing and a photovoltaic assembly.

Background Art

[0003] The solar cell body is used to realize the function of converting solar energy (light energy) into electrical energy, which is the most basic function of a solar cell, and it affects the utilization of visible and near-infrared energy and also the redistribution of mid-infrared energy. The energy of solar radiation mainly concentrates in the ultraviolet, visible, and infrared regions. Among them, the ultraviolet region accounts for 7% of the energy, the visible light region accounts for 50% of the energy, and the infrared region accounts for about 43% of the energy. Photovoltaic cells mainly absorb and utilize visible light of 400-700 nm. Infrared rays with wavelengths exceeding 1100 nm are not utilized for conversion into electrical energy by the cell sheet, but are directly converted into thermal energy, causing the internal temperature of the photovoltaic module to rise rapidly. Therefore, reasonably and effectively utilizing sunlight is an effective method to improve the operating efficiency of solar cells.

[0004] However, in reality, it is common for current white adhesive films to be added with white pigments such as silicon oxide, silicon carbide, silicon nitride, titanium oxide, titanium nitride, etc., which can achieve a high reflectivity of infrared rays, but cannot achieve a high transmittance in the visible and near-infrared regions (0.38-1.1 μm). It is common for current black adhesive films to be added with carbon black, but carbon black, etc. can only reflect 4% of infrared light in the infrared region and absorb most of the infrared light, causing the temperature of the photovoltaic module to rise.

[0005] Therefore, there is an urgent need to develop a new adhesive film structure that does not affect visible and near-infrared transmittance while having high reflectivity to infrared rays. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The main objective of the present invention is to provide an adhesive sealing film and a photovoltaic assembly in order to solve the problem of low photoelectric conversion efficiency in conventional photovoltaic assemblies. [Means for solving the problem]

[0007] To achieve the above objective, according to one aspect of the present invention, an adhesive film for sealing is provided, comprising an infrared high transmittance adhesive film layer and an infrared high reflectance adhesive film layer laminated on the infrared high transmittance adhesive film layer, wherein the infrared high transmittance adhesive film layer has a transmittance of more than 55% for light in the wavelength range of 700 to 1100 nm and a transmittance of less than 2% for light in the wavelength range of 400 to 700 nm, and the infrared high reflectance adhesive film layer has a reflectance of more than 75% for light in the wavelength range of 700 to 1100 nm.

[0008] Furthermore, the above-mentioned infrared high-transmittance adhesive film layer has a transmittance of more than 58% for light in the wavelength range of 700 to 1100 nm and a transmittance of less than 1% for light in the wavelength range of 400 to 700 nm.

[0009] Furthermore, the above-mentioned infrared high reflectivity adhesive film layer has a reflectivity greater than 85% for light in the wavelength range of 700 to 1100 nm.

[0010] Furthermore, the above-mentioned adhesive sealing film has a reflectivity greater than 70% for light in the wavelength range of 700 to 1100 nm.

[0011] Furthermore, the above-mentioned infrared high transmittance adhesive film layer contains a pigment, the pigment being one or more selected from fullerene and its derivatives, directfast dyes, direct diazo dyes, direct cross dyes, and complex metal-containing azo dyes, and the infrared high transmittance adhesive film layer comprises, by weight, 100 parts of a first olefin resin, 0.01 to 10 parts of a pigment, 0.01 to 0.1 parts of a first coupling agent, 0.01 to 0.3 parts of a first crosslinking agent, and 0.01 to 0.3 parts of a first crosslinking aid, the first olefin resin being one or more selected from ethylene-vinyl acetate ester, ethylene-octene copolymer, ethylene-α-olefin copolymer, ethylene-methyl methacrylate copolymer, ethylene-methacrylate ionomer, and metallocene-catalyzed ethylene butene copolymer.

[0012] Furthermore, by weight, the above-mentioned infrared high reflectivity adhesive film layer comprises 100 parts by weight of a second olefin resin, 5 to 40 parts of filler, 0.01 to 0.1 parts of a second coupling agent, 0.01 to 0.3 parts of a second crosslinking agent, and 0.01 to 0.3 parts of a second crosslinking aid. The second olefin resin is one or more selected from ethylene-vinyl acetate ester, ethylene-α-olefin copolymer, ethylene-methyl methacrylate copolymer, ethylene-methacrylate ionomer, and metallocene catalyst ethylene butene copolymer. The filler is one or more selected from titanium white, talcum powder, silica, aluminum hydroxide, magnesium hydroxide, alumina, boehmite, mica, kaolin, calcium carbonate, wollastonite, aluminum nitride, and boron nitride, and the particle size of the filler is 0.4 to 2.0 μm.

[0013] Furthermore, the thickness of the above-mentioned infrared high transmittance adhesive film layer is 80-300 μm, and the infrared high transmittance adhesive film layer is a pre-crosslinked film with a pre-crosslinking degree of 5-50%.

[0014] Furthermore, the thickness of the above-mentioned infrared high reflectivity adhesive film layer is 120 to 500 μm, and the infrared high reflectivity adhesive film layer is a pre-crosslinked film with a pre-crosslinking degree of 10 to 70%.

[0015] According to another aspect of the present invention, a photovoltaic assembly is provided, comprising a front transparent sealing layer, a first sealing adhesive film layer, a cell sheet array, a second sealing adhesive film layer, and a back sealing layer, wherein the second sealing adhesive film layer is the sealing adhesive film described above.

[0016] Furthermore, the infrared-high transmittance adhesive film layer of the sealing adhesive film is provided in contact with the cell sheet of the photovoltaic assembly.

[0017] When the technical solution of the present invention is applied, the infrared high transmittance adhesive film layer of the sealing adhesive film provided by this application has a transmittance of more than 55% for light in the wavelength range of 700 to 1100 nm, the infrared high transmittance adhesive film layer has a transmittance of less than 2% for light in the wavelength range of 400 to 700 nm, and the infrared high reflectance adhesive film layer has a reflectance of more than 75% for light in the wavelength range of 700 to 1100 nm. As a result, when this sealing adhesive film is used as the sealing adhesive film on the back surface of the cell sheet, it is possible to achieve a black appearance for the photovoltaic module, reduce light pollution, maximize the use of sunlight, improve the overall photoelectric conversion efficiency of the photovoltaic module, and thereby improve the efficiency and lifespan of the solar cell. Furthermore, when this sealing adhesive film is used for building-in-building photovoltaic (BIPV) integration, it is possible to achieve both the aesthetic appearance of the building and the efficiency of the photovoltaic module. [Modes for carrying out the invention]

[0018] The embodiments and features of the embodiments described herein may be combined with each other without contradiction. The present invention will now be described in detail with reference to the embodiments.

[0019] As analyzed in the background technology section, conventional technology suffers from the problem of low photoelectric conversion efficiency of photovoltaic assemblies. To solve this problem, the present invention proposes an adhesive sealing film and a photovoltaic assembly.

[0020] In one representative embodiment of the present application, an adhesive sealing film is provided, comprising an infrared high transmittance adhesive film layer and an infrared high reflectance adhesive film layer laminated on the infrared high transmittance adhesive film layer, wherein the infrared high transmittance adhesive film layer has a transmittance of more than 55% for light in the wavelength range of 700 to 1100 nm and a transmittance of less than 2% for light in the wavelength range of 400 to 700 nm, and the infrared high reflectance adhesive film layer has a reflectance of more than 75% for light in the wavelength range of 700 to 1100 nm.

[0021] The infrared high transmittance adhesive film layer of the sealing adhesive film provided by this application has a transmittance of more than 55% for light in the wavelength range of 700 to 1100 nm, a transmittance of less than 2% for light in the wavelength range of 400 to 700 nm, and an infrared high reflectance adhesive film layer has a reflectance of more than 75% for light in the wavelength range of 700 to 1100 nm. Therefore, using this sealing adhesive film as the sealing adhesive film on the back of the cell sheet not only achieves a black appearance for the photovoltaic module and reduces light pollution, but also maximizes the use of sunlight, improves the overall photoelectric conversion efficiency of the photovoltaic module, and thereby improves the efficiency and lifespan of the solar cell. Furthermore, using this sealing adhesive film for BIPV building integration allows for a balance between the aesthetic appearance of the building and the efficiency of the photovoltaic module.

[0022] Preferably, the above infrared high transmittance adhesive film layer has a transmittance of more than 58% for light in the wavelength range of 700 to 1100 nm. Preferably, the infrared high transmittance adhesive film layer has a transmittance of less than 1% for light in the wavelength range of 400 to 700 nm. Thereby, it contributes to further improving the utilization rate of the sealing adhesive film for light in the near infrared wavelength range and also reduces light damage as much as possible.

[0023] Preferably, the above infrared high reflectance adhesive film layer has a reflectance of more than 85% for light in the wavelength range of 700 to 1100 nm. Thereby, it contributes to improving the overall utilization rate of the sealing adhesive film for light in the wavelength range of 700 to 1100 nm.

[0024] In one embodiment of the present application, the above sealing adhesive film has a reflectance of more than 70% for light in the wavelength range of 700 to 1100 nm.

[0025] The sealing adhesive film having the above reflectance performance is advantageous by improving the light conversion rate of the solar power generation assembly.

[0026] In one embodiment of the present application, the infrared high transmittance adhesive film layer contains a pigment, and the pigment is any one or more selected from fullerenes and their derivatives, direct fast dyes, direct diazo dyes, direct cross dyes, and complex metal-containing azo dyes. In parts by weight, the infrared high transmittance adhesive film layer contains 100 parts of the first olefin resin, 0.01 to 10 parts of the pigment, 0.01 to 0.1 part of the first coupling agent, 0.01 to 0.3 part of the first crosslinking agent, and 0.01 to 0.3 part of the first crosslinking assistant. Preferably, the pigment is 0.01 to 0.03 parts. Preferably, the pigment is Direct Black 144, Metal Complex Dye X55, Azo Pigment B27, Aniline Black NO.2, Perylene Black LP32, Perylene Black L0086, BASF Orasol Black X51. Pigment Black 1The first olefin resin is one or more selected from ethylene-vinyl acetate, ethylene-octene copolymer, ethylene-α-olefin copolymer, ethylene-methyl methacrylate copolymer, ethylene-methacrylate ionomer, and metallocene-catalyzed ethylene-butene copolymer. Preferably, the first coupling agent is one or more selected from vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane, methacryloyloxypropyltrimethoxysilane, aminopropyltrimethoxysilane, aminopropyltriethoxysilane, and aminopropyltriisopropoxysilane. Preferably, the first crosslinking agent is tert-butylperoxyisopropyl carbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1- Bis(tert-peroxybutyl)-3,3,5-trimethylcyclohexane, tert-butylperoxy2-ethylhexyl carbonate, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-pentylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-pentylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-amylperoxycarbonate, t-butylperoxy-3,5,The first crosslinking aid is either one or more selected from 5-trimethylhexanoates, or a mixture of several of these in any ratio, and preferably the first crosslinking aid is trimethallyl isocyanurate, triallyl isocyanurate, triallyl cyanurate, divinylbenzene, diisopropenylbenzene, diallyl phthalate, allyl acrylate, allyl methacrylate, diallyl maleate, diallyl phthalate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated glyceryl triacrylate, propoxylated glyceryl It is one or more selected from triacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane trimethacrylate, triethylene glycol dimethacrylate, diethylene glycol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol (200) diacrylate, polyethylene glycol (400) diacrylate, polyethylene glycol (600) diacrylate, polyethylene glycol (200) dimethacrylate, polyethylene glycol (400) dimethacrylate, polyethylene glycol (600) dimethacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, and neopentyl glycol diacrylate.

[0027] While a higher amount of pigment added is advantageous for giving the photovoltaic assembly a black appearance, excess pigment can cause a decrease in the light transmittance of the infrared high transmittance adhesive film layer. The preferred pigment content in the infrared high transmittance adhesive film layer in this application, taking into account that the infrared high transmittance adhesive film layer is a black adhesive film, can improve the transmittance of the infrared high transmittance adhesive film layer for light in the 700-1100 nm wavelength range, and also minimize the conversion of light absorbed by the black film into thermal energy, thereby reducing the risk of overheating of the photovoltaic assembly. The preferred first coupling agent, first crosslinking agent, and first crosslinking aid are advantageous for improving the crosslinking effect of the first olefin resin. Naturally, those skilled in the art may select other suitable types of first coupling agents, first crosslinking agents, and first crosslinking aids, which will not be described in detail here.

[0028] In one embodiment of the present application, the infrared high reflectivity adhesive film layer comprises, by weight, 100 parts by weight of a second olefin resin, 5 to 40 parts of a filler, 0.01 to 0.1 parts of a second coupling agent, 0.01 to 0.3 parts of a second crosslinking agent, and 0.01 to 0.3 parts of a second crosslinking aid, wherein the second olefin resin is one or more selected from ethylene-vinyl acetate ester, ethylene-α-olefin copolymer, ethylene-methyl methacrylate copolymer, ethylene-methacrylate ionomer, and metallocene catalyst ethylene butene copolymer, and the filler is one or more selected from titanium white, talcum powder, silica, aluminum hydroxide, magnesium hydroxide, alumina, boehmite, mica, kaolin, calcium carbonate, wollastonite, aluminum nitride, and boron nitride, and the particle size of the filler is 0.4 to 2.0 μm, preferably 0.7 to 2.0 μm. Preferably, the second coupling agent is one or more selected from vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane, methacryloyloxypropyltrimethoxysilane, aminopropyltrimethoxysilane, aminopropyltriethoxysilane, and aminopropyltriisopropoxysilane, and preferably the second crosslinking agent is tert-butylperoxyisopropyl carbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1- Bis(tert-peroxybutyl)-3,3,5-trimethylcyclohexane, tert-butylperoxy2-ethylhexyl carbonate, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-pentylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-pentylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-amylperoxycarbonate, t-butylperoxy-3,5,One or more selected from 5-trimethylhexanoate, or any one or more of a mixture of one or more of these in any ratio, preferably, the second crosslinking aid is trimethylol isocyanurate, triallyl isocyanurate, triallyl cyanurate, divinylbenzene, diisopropenylbenzene, diallyl phthalate, allyl acrylate, allyl methacrylate, diallyl maleate, diallyl phthalate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated glyceryl triacrylate, propoxylated glyceryl triacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane trimethacrylate, triethylene glycol dimethacrylate, diethylene glycol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol (200) diacrylate, polyethylene glycol (400) diacrylate, polyethylene glycol (600) diacrylate, polyethylene glycol (200) dimethacrylate, polyethylene glycol (400) dimethacrylate, polyethylene glycol (600) dimethacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, neopentyl glycol diacrylate, any one or more selected therefrom.,

[0029] The filler in the infrared high reflectivity adhesive film layer of this application makes the infrared high reflectivity adhesive film layer a white adhesive film, which is advantageous in improving the reflectivity of the sealing adhesive film to irradiated light. Since titanium dioxide with a large particle size has a higher near-infrared reflectivity, titanium dioxide within the preferred particle size range has a higher near-infrared reflectivity. Adding an excess of filler causes the filler to accumulate, reducing the effective specific surface area that reflects sunlight and thereby lowering the overall reflectivity of the sealing adhesive film. Therefore, preferably, 5 to 15 parts of filler is advantageous in improving the reflectivity of the sealing adhesive film to irradiated light. Preferred second coupling agents, second crosslinking agents, and second crosslinking aids are advantageous in improving the crosslinking effect of the second olefin resin. Of course, those skilled in the art may select other suitable types of second coupling agents, second crosslinking agents, and second crosslinking aids, which will not be described in detail here.

[0030] The thickness of the infrared high transmittance adhesive film layer affects the transmittance of the irradiated light to some extent. A thickness of 80 to 300 μm for the infrared high transmittance adhesive film layer is advantageous in improving the overall transmittance of the infrared high transmittance adhesive film layer for light in the wavelength range of 700 to 1100 nm. The infrared high transmittance adhesive film layer is preferably a pre-crosslinked film, and the degree of pre-crosslinking of the infrared high transmittance adhesive film layer is preferably 5 to 50%. This contributes to avoiding the risk of the infrared high transmittance adhesive film layer migrating to the front of the battery, is advantageous in ensuring a good laminated appearance of the photovoltaic assembly, and avoids unnecessary power loss at the front of the photovoltaic assembly. If there is no risk of the infrared high transmittance adhesive film layer migrating upward, a lower degree of pre-crosslinking of the infrared high transmittance adhesive film layer is advantageous in reducing or avoiding the phenomenon of cracking or fissures in the battery.

[0031] The thickness of the above-mentioned infrared high reflectivity adhesive film layer is preferably 120 to 500 μm, which is advantageous for improving the overall reflectivity of the infrared high reflectivity adhesive film layer for light in the wavelength range of 700 to 1100 nm. The infrared high reflectivity adhesive film layer is preferably a pre-crosslinked film, and the degree of pre-crosslinking of the infrared high reflectivity adhesive film layer is preferably 10 to 70%. This is advantageous for avoiding the risk of the infrared high reflectivity adhesive film layer migrating to the front of the battery due to flow of the infrared high reflectivity adhesive film layer, ensuring a good laminated appearance of the photovoltaic assembly and avoiding unnecessary power loss from the front of the photovoltaic assembly.

[0032] Preferably, the degree of pre-crosslinking of the infrared high transmittance adhesive film layer is lower than that of the infrared high reflectance adhesive film layer. This contributes to achieving both a good appearance for the photovoltaic assembly and the integrity of the battery.

[0033] In another representative embodiment of the present application, a photovoltaic assembly is provided, comprising a front transparent sealing layer, a first sealing adhesive film layer, a cell sheet array, a second sealing adhesive film layer, and a back sealing layer, wherein the second sealing adhesive film layer is the sealing adhesive film described above.

[0034] Using the above-mentioned adhesive sealing film as the second adhesive sealing film layer on the back of the cell sheet array maximizes the use of sunlight, improves the overall photoelectric conversion efficiency of the solar power generation module, and thereby improves the efficiency and lifespan of the solar cells.

[0035] Preferably, the infrared high transmittance adhesive film layer of the sealing adhesive film is provided in contact with the cell sheet of the photovoltaic assembly. Some of the sunlight irradiated onto the sealing adhesive film is absorbed by the cell sheet after passing through the infrared high transmittance adhesive film layer, while other sunlight is converted into reflected light by the infrared high reflectance adhesive film layer, which is then secondarily reflected back to the sealing adhesive film via the inner surface of the backplate, passes through the infrared high transmittance adhesive film layer, and reaches the cell sheet. In this way, the overall reflectance of the sealing adhesive film is improved, and therefore the overall photoelectric conversion efficiency of the photovoltaic assembly is increased.

[0036] The beneficial effects of this application will be explained below with reference to specific examples and comparative examples.

[0037] Example 1 Formulation of infrared high transmittance adhesive film layer E1-1: 100 parts ethylene-octen copolymer, 0.01 parts azo pigment B27, 0.01 parts vinyltrimethoxysilane, 0.01 parts tert-butylperoxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0038] Formulation of infrared high reflectivity adhesive film layer E1-2: 100 parts ethylene vinyl acetate, 5 parts titanium white (particle size 1 μm), 0.01 parts vinyl trimethoxysilane, 0.01 parts tert-butyl peroxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0039] E1-1 and E1-2 were co-extruded in multilayer form to produce a two-layer adhesive film for photovoltaic encapsulation, which was designated E1. The thickness of the infrared high transmittance adhesive film layer E1-1 of the obtained encapsulation adhesive film was 0.2 mm, and the thickness of the infrared high reflectance adhesive film layer E1-2 was 0.3 mm. Here, the pre-crosslinking degree of the infrared high transmittance adhesive film layer E1-1 was 10%, and the pre-crosslinking degree of the infrared high reflectance adhesive film layer E1-2 was 15%.

[0040] Example 2 Compared to Example 1, Example 2 differs in the following respects.

[0041] Formulation of infrared high transmittance adhesive film layer E2-1: 100 parts ethylene-octen copolymer, 0.03 parts azo pigment B27, 0.01 parts vinyltrimethoxysilane, 0.01 parts tert-butylperoxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0042] Formulation of infrared high reflectivity adhesive film layer E2-2: 100 parts ethylene vinyl acetate, 5 parts titanium white (particle size 1 μm), 0.01 parts vinyl trimethoxysilane, 0.01 parts tert-butyl peroxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0043] E2-1 and E2-2 were co-extruded in multilayer form to produce a two-layer adhesive film for encapsulating solar power generation equipment, which was designated E2. The thickness of the infrared high transmittance adhesive film layer E2-1 of the obtained encapsulating adhesive film was 0.2 mm, and the thickness of the infrared high reflectance adhesive film layer E2-2 was 0.3 mm. Here, the pre-crosslinking degree of the infrared high transmittance adhesive film layer E2-1 was 10%, and the pre-crosslinking degree of the infrared high reflectance adhesive film layer E2-2 was 15%.

[0044] Example 3 Compared to Example 1, Example 3 differs in the following respects.

[0045] Formulation of infrared high transmittance adhesive film layer E3-1: 100 parts ethylene-octen copolymer, 10 parts azo pigment B27, 0.01 parts vinyltrimethoxysilane, 0.01 parts tert-butylperoxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0046] Formulation of infrared high reflectivity adhesive film layer E3-2: 100 parts ethylene vinyl acetate, 5 parts titanium white (particle size 1 μm), 0.01 parts vinyl trimethoxysilane, 0.01 parts tert-butyl peroxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0047] E3-1 and E3-2 were co-extruded in multilayer form to produce a two-layer adhesive film for photovoltaic encapsulation, which was designated E3. The thickness of the infrared high transmittance film E3-1 layer of the obtained adhesive encapsulation film was 0.2 mm, and the thickness of the infrared high reflectance adhesive film layer E3-2 was 0.3 mm. Here, the pre-crosslinking degree of the infrared high transmittance adhesive film layer E3-1 was 10%, and the pre-crosslinking degree of the infrared high reflectance adhesive film layer E3-2 was 15%.

[0048] Example 4 Compared to Example 1, Example 4 differs in the following respects.

[0049] Formulation of infrared high transmittance adhesive film layer E4-1: 100 parts ethylene-octen copolymer, 0.01 parts perylene black L0086, 0.01 parts vinyl trimethoxysilane, 0.01 parts tert-butyl peroxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0050] Formulation of infrared high reflectivity adhesive film layer E4-2: 100 parts ethylene vinyl acetate, 5 parts titanium white (particle size 1 μm), 0.01 parts vinyl trimethoxysilane, 0.01 parts tert-butyl peroxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0051] E4-1 and E4-2 were co-extruded in multilayer form to produce a two-layer adhesive film for photovoltaic encapsulation, which was designated E4. The thickness of the infrared high transmittance adhesive film layer E4-1 of the obtained encapsulation adhesive film was 0.2 mm, and the thickness of the infrared high reflectance adhesive film layer E4-2 was 0.3 mm. Here, the pre-crosslinking degree of the infrared high transmittance adhesive film layer E4-1 was 10%, and the pre-crosslinking degree of the infrared high reflectance adhesive film layer E4-2 was 15%.

[0052] Example 5 Compared to Example 1, Example 5 differs in the following respects.

[0053] Formulation of infrared high transmittance adhesive film layer E5-1: 100 parts of ethylene-octen copolymer, Pigment Black 1 0.01 parts of vinyltrimethoxysilane, 0.01 parts of tert-butylperoxyisopropyl carbonate, and 0.01 parts of propoxylated pentaerythritol tetraacrylate.

[0054] Formulation of infrared high reflectivity adhesive film layer E5-2: 100 parts ethylene vinyl acetate, 5 parts titanium white (particle size 1 μm), 0.01 parts vinyl trimethoxysilane, 0.01 parts tert-butyl peroxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0055] E5-1 and E5-2 were co-extruded in multilayer form to produce a two-layer adhesive film for photovoltaic encapsulation, which was designated E5. The thickness of the infrared high transmittance adhesive film layer E5-1 of the obtained encapsulation adhesive film was 0.2 mm, and the thickness of the infrared high reflectance adhesive film layer E5-2 was 0.3 mm. Here, the pre-crosslinking degree of the infrared high transmittance adhesive film layer E5-1 was 10%, and the pre-crosslinking degree of the infrared high reflectance adhesive film layer E5-2 was 15%.

[0056] Example 6 Compared to Example 1, Example 6 differs in the following respects.

[0057] Formulation of infrared high transmittance adhesive film layer E6-1: 100 parts ethylene-octen copolymer, 5 parts azo pigment B27, 0.05 parts vinyltrimethoxysilane, 0.2 parts tert-butylperoxyisopropyl carbonate, 0.2 parts propoxylated pentaerythritol tetraacrylate.

[0058] Formulation of infrared high reflectivity adhesive film layer E6-2: 100 parts ethylene vinyl acetate, 25 parts titanium white (particle size 1 μm), 0.05 parts vinyl trimethoxysilane, 0.2 parts tert-butyl peroxyisopropyl carbonate, 0.2 parts propoxylated pentaerythritol tetraacrylate.

[0059] E6-1 and E6-2 were co-extruded in multilayer form to produce a two-layer adhesive film for photovoltaic encapsulation, which was designated E6. The thickness of the infrared high transmittance adhesive film layer E6-1 of the obtained encapsulation adhesive film was 0.2 mm, and the thickness of the infrared high reflectance adhesive film layer E6-2 was 0.3 mm. Here, the pre-crosslinking degree of the infrared high transmittance adhesive film layer E6-1 was 20%, and the pre-crosslinking degree of the infrared high reflectance adhesive film layer E6-2 was 40%.

[0060] Example 7 Compared to Example 1, Example 7 differs in the following respects.

[0061] Infrared high transmittance film E7-1 layer formulation: 100 parts ethylene-octen copolymer, 10 parts azo pigment B27, 0.1 parts vinyltrimethoxysilane, 0.3 parts tert-butylperoxyisopropyl carbonate, 0.8 parts propoxylated pentaerythritol tetraacrylate.

[0062] Formulation of infrared high reflectivity adhesive film layer E7-2: 100 parts ethylene vinyl acetate, 40 parts titanium white (particle size 1 μm), 0.1 parts vinyl trimethoxysilane, 0.3 parts tert-butyl peroxyisopropyl carbonate, 0.3 parts propoxylated pentaerythritol tetraacrylate.

[0063] E7-1 and E7-2 were co-extruded in multiple layers to produce a two-layer adhesive film for photovoltaic encapsulation, which was designated E7. The thickness of the infrared high transmittance adhesive film layer E7-1 of the obtained encapsulation adhesive film was 0.2 mm, and the thickness of the infrared high reflectance adhesive film layer E7-2 was 0.3 mm. Here, the pre-crosslinking degree of the infrared high transmittance adhesive film layer E7-1 was 50%, and the pre-crosslinking degree of the infrared high reflectance adhesive film layer E7-2 was 50%.

[0064] Example 8 Compared to Example 1, Example 8 differs in the following respects.

[0065] Formulation of infrared high transmittance adhesive film layer E8-1: 100 parts ethylene-α-olefin copolymer, 0.01 parts azo pigment B27, 0.1 parts methacryloyloxypropyltrimethoxysilane, 0.3 parts 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 0.3 parts ethoxylated glyceryl triacrylate.

[0066] Formulation of infrared high reflectivity adhesive film layer E8-2: 100 parts ethylene-methacrylate ionomer, 40 parts alumina (particle size 1 μm), 0.1 parts vinyl tri(β-methoxyethoxy)silane, 0.3 parts 2,2-bis(tert-butylperoxy)butane, 0.3 parts polyethylene glycol (200) diacrylate.

[0067] E8-1 and E8-2 were co-extruded in multilayer form to produce a two-layer adhesive film for photovoltaic encapsulation, which was designated E8. The thickness of the infrared high transmittance adhesive film layer E8-1 of the obtained encapsulation adhesive film was 0.2 mm, the thickness of the infrared high reflectance adhesive film layer E8-2 was 0.3 mm, the pre-crosslinking degree of the infrared high transmittance adhesive film layer E8-1 was 10%, and the pre-crosslinking degree of the infrared high reflectance adhesive film layer E8-2 was 15%.

[0068] Example 9 Compared to Example 1, Example 9 differs in the following respects.

[0069] Formulation of infrared high transmittance adhesive film layer E9-1: 100 parts ethylene-octen copolymer, 0.01 parts azo pigment B27, 0.01 parts vinyltrimethoxysilane, 0.01 parts tert-butylperoxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0070] Formulation of infrared high reflectivity adhesive film layer E9-2: 100 parts ethylene vinyl acetate, 5 parts titanium white (particle size 0.7 μm), 0.01 parts vinyl trimethoxysilane, 0.01 parts tert-butyl peroxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0071] E9-1 and E9-2 were co-extruded in multiple layers to produce a two-layer adhesive film for encapsulating solar power generation equipment, which was designated E9. The thickness of the infrared high transmittance adhesive film layer E9-1 of the obtained encapsulating adhesive film was 0.2 mm, and the thickness of the infrared high reflectance adhesive film layer E9-2 was 0.3 mm. Here, the pre-crosslinking degree of the infrared high transmittance adhesive film layer E9-1 was 10%, and the pre-crosslinking degree of the infrared high reflectance adhesive film layer E9-2 was 15%.

[0072] Example 10 Compared to Example 1, Example 10 differs in the following respects.

[0073] Formulation of infrared high transmittance adhesive film layer E10-1: 100 parts ethylene-octen copolymer, 0.01 parts azo pigment B27, 0.01 parts vinyltrimethoxysilane, 0.01 parts tert-butylperoxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0074] Formulation of infrared high reflectivity adhesive film layer E10-2: 100 parts ethylene vinyl acetate, 5 parts titanium white (particle size 0.4 μm), 0.01 parts vinyl trimethoxysilane, 0.01 parts tert-butyl peroxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0075] E10-1 and E10-2 were co-extruded in multilayer form to produce a two-layer adhesive film for photovoltaic encapsulation, which was designated E10. The thickness of the infrared high transmittance adhesive film layer E10-1 of the obtained encapsulation adhesive film was 0.2 mm, and the thickness of the infrared high reflectance adhesive film layer E10-2 was 0.3 mm. Here, the pre-crosslinking degree of the infrared high transmittance adhesive film layer E10-1 was 10%, and the pre-crosslinking degree of the infrared high reflectance adhesive film layer E10-2 was 15%.

[0076] Example 11 Compared to Example 1, Example 11 differs in the following respects.

[0077] Formulation of infrared high transmittance adhesive film layer E11-1: 100 parts ethylene-octen copolymer, 0.01 parts azo pigment B27, 0.01 parts vinyltrimethoxysilane, 0.01 parts tert-butylperoxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0078] Formulation of infrared high reflectivity adhesive film layer E11-2: 100 parts ethylene vinyl acetate, 5 parts titanium white (particle size 2 μm), 0.01 parts vinyl trimethoxysilane, 0.01 parts tert-butyl peroxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0079] E11-1 and E11-2 were co-extruded in multilayer form to produce a two-layer adhesive film for photovoltaic encapsulation, which was designated E11. The thickness of the infrared high transmittance adhesive film layer E11-1 in the obtained encapsulation adhesive film was 0.2 mm, and the thickness of the infrared high reflectance adhesive film layer E11-2 was 0.3 mm. Here, the pre-crosslinking degree of the infrared high transmittance adhesive film layer E11-1 was 10%, and the pre-crosslinking degree of the infrared high reflectance adhesive film layer E11-2 was 15%.

[0080] Example 12 Compared to Example 1, Example 12 differs in the following respects.

[0081] Formulation of infrared high transmittance adhesive film layer E12-1: 100 parts ethylene-octen copolymer, 0.01 parts azo pigment B27, 0.01 parts vinyltrimethoxysilane, 0.01 parts tert-butylperoxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0082] Formulation of infrared high reflectivity adhesive film layer E12-2: 100 parts ethylene vinyl acetate, 5 parts titanium white (particle size 1 μm), 0.01 parts vinyl trimethoxysilane, 0.01 parts tert-butyl peroxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0083] E12-1 and E12-2 were co-extruded in multilayer form to produce a two-layer adhesive film for photovoltaic encapsulation, which was designated E12. The thickness of the obtained adhesive encapsulation film was 0.08 mm for the infrared high transmittance adhesive film layer E12-1 and 0.12 mm for the infrared high reflectance adhesive film layer E12-2. The pre-crosslinking degree of the infrared high transmittance adhesive film layer E12-1 was 10%, and the pre-crosslinking degree of the infrared high reflectance adhesive film layer E12-2 was 15%.

[0084] Example 13 Compared to Example 1, Example 13 differs in the following respects.

[0085] Formulation of infrared high transmittance adhesive film layer E13-1: 100 parts ethylene-octen copolymer, 0.01 parts azo pigment B27, 0.01 parts vinyltrimethoxysilane, 0.01 parts tert-butylperoxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0086] Formulation of infrared high reflectivity adhesive film layer E13-2: 100 parts ethylene vinyl acetate, 5 parts titanium white (particle size 1 μm), 0.01 parts vinyl trimethoxysilane, 0.01 parts tert-butyl peroxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0087] E13-1 and E13-2 were co-extruded in multilayer form to produce a two-layer adhesive film for photovoltaic encapsulation, which was designated E13. The thickness of the obtained adhesive encapsulation film was 0.3 mm for the infrared high transmittance adhesive film layer E13-1 and 0.5 mm for the infrared high reflectance adhesive film layer E13-2. The pre-crosslinking degree of the infrared high transmittance adhesive film layer E13-1 was 10%, and the pre-crosslinking degree of the infrared high reflectance adhesive film layer E13-2 was 15%.

[0088] Example 14 Compared to Example 1, Example 14 differs in the following respects.

[0089] Formulation of infrared high transmittance adhesive film layer E14-1: 100 parts ethylene vinyl acetate, 0.01 parts azo pigment B27, 0.01 parts vinyl trimethoxysilane, 0.01 parts tert-butyl peroxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0090] Formulation of infrared high reflectivity adhesive film layer E14-2: 100 parts ethylene vinyl acetate, 5 parts titanium white (particle size 1 μm), 0.01 parts vinyl trimethoxysilane, 0.01 parts tert-butyl peroxyisopropyl carbonate, 0.01 parts propoxylated pentaerythritol tetraacrylate.

[0091] E14-1 and E14-2 were co-extruded in multilayer form to produce a two-layer adhesive film for photovoltaic encapsulation, which was designated E14. The thickness of the obtained adhesive encapsulation film was 0.2 mm for the infrared high transmittance adhesive film layer E14-1 and 0.3 mm for the infrared high reflectance adhesive film layer E14-2. The pre-crosslinking degree of the infrared high transmittance adhesive film layer E14-1 was 10%, and the pre-crosslinking degree of the infrared high reflectance adhesive film layer E14-2 was 15%.

[0092] Photovoltaic Assembly: Tempered glass, a standard transparent sealing adhesive film, a crystalline silicon cell sheet, sealing adhesive films E1-E14 (the infrared high transmittance adhesive film layers E1-1-E14-1 of sealing adhesive films E1-E14 are provided in contact with the crystalline silicon cell sheet), and a transparent backplate were arranged sequentially from top to bottom and laminated at 145°C using a laminator to obtain the corresponding black photovoltaic assemblies PV-1-PV-14.

[0093] Comparative Example 1: Tempered glass, a standard transparent adhesive sealing film, a crystalline silicon cell sheet, a standard transparent EVA adhesive sealing film F806PS, and a black backplate BEC306HB were arranged sequentially from top to bottom and laminated at 145°C using a laminator to obtain the corresponding black photovoltaic assembly PV-D1.

[0094] The transmittance and reflectivity of the infrared high transmittance adhesive film layers E1-1 to E14-1, infrared high reflectance adhesive film layers E1-2 to E14-2, and sealing adhesive films E1 to E14 obtained in the above Examples 1 to 14 were tested, and the test results are shown in Table 1.

[0095] Testing Method Transmittance testing: Tests were conducted according to the GB / T 2410-2008 standard, and the transmittance of the infrared high transmittance adhesive film layers E1-1 to E14-1 was measured using a UV-Vis spectrophotometer.

[0096] Reflectance Test: Tests were conducted according to the GB / T 29848 standard, and the reflectance of the infrared high reflectance adhesive film layers E1-2~E14-2 and sealing adhesive films E1~E14 was measured using a UV-Vis spectrophotometer. [Table 1]

[0097] As can be seen from the data in Table 1, compared to Example 1, in Examples 6 and 7, the addition of excess titanium white caused the accumulation of titanium white, which reduced the effective specific surface area that reflects sunlight, and ultimately lowered the overall reflectivity of the sealing adhesive film to some extent.

[0098] Compared to Example 1, Examples 6 and 7 contain too much azo pigment B27, which reduces the transmittance of the infrared high transmittance adhesive film layer to sunlight.

[0099] In Example 8, changing the amount and type of crosslinking agent and crosslinking aid also significantly affects the transmittance of the high infrared transmittance adhesive film layer to sunlight, and the reflectance of the high infrared transmittance adhesive film layer and the sealing adhesive film to sunlight.

[0100] PID testing of photovoltaic assemblies: All front adhesive films used were F406PS transparent adhesive films, and all P-type double-sided batteries from manufacturer A were used. PID testing of the photovoltaic modules was performed according to IEC TS2804-1:2015, with test conditions of 85°C, 85%RH, and a constant DC voltage of -1500V. After 192 hours, the power decay of the photovoltaic modules was measured before and after the PID test, and the test results are shown in Table 2. [Table 2]

[0101] As can be seen from the above description, the above embodiment of the present invention achieves the following technical effects.

[0102] The infrared high transmittance adhesive film layer of the sealing adhesive film provided by this application has a transmittance of more than 55% for light in the wavelength range of 700 to 1100 nm and a transmittance of less than 2% for light in the wavelength range of 400 to 700 nm, while the infrared high reflectance adhesive film layer has a reflectance of more than 75% for light in the wavelength range of 700 to 1100 nm. Therefore, using this sealing adhesive film as the sealing adhesive film on the back of a cell sheet not only achieves a black appearance for the photovoltaic module and reduces light pollution, but also maximizes the use of sunlight, improving the overall photoelectric conversion efficiency of the photovoltaic module, thereby improving the efficiency and lifespan of the solar cell. Furthermore, using this sealing adhesive film for BIPV building integration allows for a balance between the aesthetic appearance of the building and the efficiency of the photovoltaic module.

[0103] PID comparative tests clearly show that the sealing adhesive film provided by this application, because it uses an inorganic filler in the infrared high reflectivity adhesive film layer, is advantageous in improving the PID resistance performance of P-type double-sided photovoltaic assemblies. In particular, when pure titanium white filler is used in the infrared high reflectivity adhesive film layer, the infrared high reflectivity adhesive film layer exhibits significantly improved PID resistance compared to ordinary transparent films. This is thought to be related to the electronegativity of titanium white, or that titanium white has the function of delaying the penetration of sodium ions into the sealing adhesive film.

[0104] The foregoing are merely preferred embodiments of the present invention and do not limit the present invention. Various modifications and changes are possible for those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made in the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A sealing adhesive film, The material comprises an infrared high transmittance adhesive film layer and an infrared high reflectance adhesive film layer laminated on the infrared high transmittance adhesive film layer, wherein the infrared high transmittance adhesive film layer has a transmittance of more than 55% for light in the wavelength range of 700 nm to 1100 nm and a transmittance of less than 2% for light in the wavelength range of 400 nm to 700 nm, and the infrared high reflectance adhesive film layer has a reflectance of more than 75% for light in the wavelength range of 700 nm to 1100 nm. The infrared high transmittance adhesive film layer contains a pigment, and the pigment is one or more selected from azo pigment B27, perylene black LP32, perylene black L0086, and pigment black 1. The infrared high transmittance adhesive film layer is a pre-crosslinked film, and the infrared high reflectance adhesive film layer is a pre-crosslinked film, and the degree of pre-crosslinking of the infrared high transmittance adhesive film layer is lower than the degree of pre-crosslinking of the infrared high reflectance adhesive film layer. The infrared high transmittance adhesive film layer contains 0.01 to 10 parts by weight of pigment. The sealing adhesive film is characterized in that the infrared high reflectivity adhesive film layer contains 5 to 40 parts of filler, and the particle size of the filler is 0.4 to 2.0 μm.

2. The sealing adhesive film according to claim 1, characterized in that the infrared high transmittance adhesive film layer has a transmittance of more than 58% for light in the wavelength range of 700 nm to 1100 nm and a transmittance of less than 1% for light in the wavelength range of 400 nm to 700 nm.

3. The sealing adhesive film according to claim 1, characterized in that the infrared high reflectivity adhesive film layer has a reflectivity of more than 85% for light in the wavelength range of 700 nm to 1100 nm.

4. The sealing adhesive film according to any one of claims 1 to 3, characterized in that its reflectance for light in the wavelength range of 700 nm to 1100 nm is greater than 70%.

5. By weight, the infrared high transmittance adhesive film layer further comprises 100 parts of a first olefin resin, 0.01 to 0.1 parts of a first coupling agent, 0.01 to 0.3 parts of a first crosslinking agent, and 0.01 to 0.3 parts of a first crosslinking aid. The sealing adhesive film according to any one of claims 1 to 3, characterized in that the first olefin resin is one or more selected from ethylene-vinyl acetate ester, ethylene-octene copolymer, ethylene-α-olefin copolymer, ethylene-methyl methacrylate copolymer, ethylene-methacrylate ionomer, and metallocene-catalyzed ethylene-butene copolymer.

6. By weight, the infrared high reflectivity adhesive film layer further comprises 100 parts of a second olefin resin, 0.01 to 0.1 parts of a second coupling agent, 0.01 to 0.3 parts of a second crosslinking agent, and 0.01 to 0.3 parts of a second crosslinking aid. The second olefin resin is one or more selected from ethylene-vinyl acetate ester, ethylene-α-olefin copolymer, ethylene-methyl methacrylate copolymer, ethylene-methacrylate ionomer, and metallocene-catalyzed ethylene butene copolymer. The sealing adhesive film according to any one of claims 1 to 3, characterized in that the filler is one or more selected from titanium white, talcum powder, silica, aluminum hydroxide, magnesium hydroxide, alumina, boehmite, mica, kaolin, calcium carbonate, wollastonite, aluminum nitride, and boron nitride.

7. The sealing adhesive film according to any one of claims 1 to 3, characterized in that the thickness of the infrared high transmittance adhesive film layer is 80 μm to 300 μm, and the infrared high transmittance adhesive film layer has a pre-crosslinking degree of 5% to 50%.

8. The sealing adhesive film according to any one of claims 1 to 3, characterized in that the thickness of the infrared high reflectivity adhesive film layer is 120 μm to 500 μm, and the infrared high reflectivity adhesive film layer has a pre-crosslinking degree of 10% to 70%.

9. A photovoltaic assembly comprising a front transparent sealing layer, a first sealing adhesive film layer, a cell sheet array, a second sealing adhesive film layer, and a back sealing layer, The photovoltaic assembly is characterized in that the second sealing adhesive film layer is the sealing adhesive film described in any one of claims 1 to 3.

10. The photovoltaic assembly according to claim 9, characterized in that the infrared high transmittance adhesive film layer of the sealing adhesive film is provided in contact with the cell sheet of the photovoltaic assembly.

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