Composite packaging adhesive film and double-glass photovoltaic module

Abstract

The invention provides a composite packaging adhesive film and a double-glass photovoltaic module. The composite packaging adhesive film comprises an infrared reflecting layer and a transparent adhesive film layer which are stacked in sequence, materials of the infrared reflecting layer comprise an infrared reflecting material and first matrix resin, and the mass content of the infrared reflecting material in the materials of the infrared reflecting layer is 1-30%. The composite packaging adhesive film comprises the infrared reflecting layer and the transparent adhesive film layer which are stacked in sequence, and when the composite packaging adhesive film serves as the packaging adhesive film on the back face of the double-glass photovoltaic module, infrared light penetrating through a battery piece of the double-glass photovoltaic module can be reflected back to the back face of the battery piece under the action of the infrared reflecting layer for secondary utilization; therefore, the utilization rate of the double-glass photovoltaic module to infrared light is improved, and the overall utilization rate of the battery piece to sunlight is further improved. Meanwhile, visible light penetrating through the back glass can penetrate through the composite packaging adhesive film to irradiate the back of the battery piece to be utilized, and therefore the light receiving efficiency of the two faces of the battery piece can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic modules, and more particularly, to a composite encapsulation film and a double-glass photovoltaic module. Background Art

[0002] In order to solve the problem that some sunlight directly passes through the solar cell and cannot be fully absorbed, a high-reflection film is used on the back of the solar cell, which can reflect the sunlight that reaches the bottom of the cell but is not absorbed back into the cell for secondary or even multiple absorptions, thereby improving the light absorption rate of the cell. Currently, high-reflection white films are a hot topic in the industry, but high-reflection white films are often used in single-glass photovoltaic modules and are not suitable for heterojunction cells with a high bifaciality. What heterojunction cells need is an encapsulation film that can reflect infrared light and transmit visible light. Therefore, it is particularly important to develop a high-infrared-reflection transparent film for double-glass photovoltaic modules. Summary of the Invention

[0003] The main object of the present invention is to provide a composite encapsulation film and a double-glass photovoltaic module to solve the problem of low infrared reflectivity of the encapsulation film in the existing double-glass photovoltaic module.

[0004] To achieve the above object, according to one aspect of the present invention, there is provided a composite encapsulation film, which includes an infrared reflection layer and a transparent film layer stacked in sequence; the material of the infrared reflection layer includes an infrared reflection material and a first matrix resin, and the mass content of the infrared reflection material in the material of the infrared reflection layer is 1-30%.

[0005] Further, the above composite encapsulation film satisfies at least one of the following conditions: (1) the visible light transmittance of the infrared reflection layer is greater than 60%; (2) the infrared reflectivity of the infrared reflection layer is greater than 20%; (3) the visible light transmittance of the transparent film layer is greater than 90%; (4) the infrared reflectivity of the composite encapsulation film is 20-75%; (5) the visible light transmittance of the composite encapsulation film is 75-93%.

[0006] Further, the infrared reflectivity of the above infrared reflection layer in the 800-2000 nm band is 15-50%.

[0007] Further, the mass content of the infrared reflection material in the material of the above infrared reflection layer is 2-10%; preferably, the material of the infrared reflection layer further includes a first auxiliary agent, and the mass ratio of the first matrix resin to the first auxiliary agent is 100: (2-5); preferably, the first auxiliary agent is selected from any one or more of a first crosslinking agent, a first co-crosslinking agent, a first light stabilizer, and a first tackifier.

[0008] Further, the thickness of the above infrared reflection layer is 100 μm to 200 μm; and / or, the thickness of the transparent adhesive film layer is 100 μm to 400 μm; preferably, the ratio of the thickness of the infrared reflection layer to the thickness of the transparent adhesive film layer is 1:1 to 2.

[0009] Further, the above infrared reflection material is selected from any one or more of rare earth oxides, non-rare earth metal oxides, cesium tungsten bronze, yttrium molybdate, strontium copper silicate, bismuth oxychloride, and zirconium carbide; preferably, the non-rare earth metal oxide is selected from any one or more of indium tin oxide, antimony tin oxide, tin oxide, vanadium dioxide, aluminum-doped zinc oxide, chromium oxide, and titanium oxide.

[0010] Further, the above infrared reflection material is a mixture of rare earth oxides and non-rare earth metal oxides, and the mass ratio of rare earth oxides to non-rare earth metal oxides is 1:0.1 to 10, preferably 1:(1 to 5).

[0011] Further, the above first matrix resin is selected from any one or more of ethylene-vinyl acetate copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, silicone, and polyvinyl butyral.

[0012] Further, by weight, the material of the above transparent adhesive film layer includes 100 parts of a second matrix resin and 2 to 5 parts of a second auxiliary agent; preferably, the second matrix resin is selected from any one or more of ethylene-vinyl acetate copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, silicone, and polyvinyl butyral; preferably, the second auxiliary agent is selected from any one or more of a second crosslinking agent, a second co-crosslinking agent, a second light stabilizer, and a second tackifier.

[0013] According to another aspect of the present invention, a double-glass photovoltaic module is provided, which includes a front glass, a first encapsulation adhesive film, a battery cell, a second encapsulation adhesive film, and a back glass stacked in sequence, and the second encapsulation adhesive film is the aforementioned composite encapsulation adhesive film; wherein, the infrared reflection layer of the composite encapsulation adhesive film is in contact with the battery cell, and the transparent adhesive film layer is in contact with the back glass.

[0014] Applying the technical solution of the present application, the composite encapsulation film of the present application includes an infrared reflection layer and a transparent film layer stacked in sequence. When the composite encapsulation film is used as the encapsulation film on the back of a double-glass photovoltaic module, the infrared light passing through the cells of the double-glass photovoltaic module can be reflected back to the back of the cells for secondary utilization under the action of the infrared reflection layer, thereby improving the utilization rate of infrared light by the double-glass photovoltaic module, and further improving the overall utilization rate of sunlight by the cells. Controlling the mass content of the infrared reflection material in the material of the infrared reflection layer within the above range helps to ensure the visible light transmittance of the infrared reflection layer while increasing the infrared reflectivity of the infrared reflection layer. The transparent film layer has a higher visible light transmittance than the infrared reflection layer. The synergistic effect of the infrared reflection layer and the transparent film layer helps the composite encapsulation film to have both a high infrared reflectivity and a high visible light transmittance. At the same time, the visible light passing through the back glass can pass through the composite encapsulation film and irradiate the back of the cells for utilization, which helps to improve the light-receiving efficiency on both sides of the cells, and further helps to improve the overall power of the double-glass photovoltaic module. Detailed implementation manners

[0015] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0016] As analyzed in the background art of the present application, there is a problem of low infrared reflectivity in the encapsulation film of double-glass photovoltaic modules in the prior art. To solve this problem, the present application provides a composite encapsulation film and a double-glass photovoltaic module.

[0017] In a typical implementation manner of the present application, a composite encapsulation film is provided. The composite encapsulation film includes an infrared reflection layer and a transparent film layer stacked in sequence; the material of the infrared reflection layer includes an infrared reflection material and a first matrix resin, and the mass content of the infrared reflection material in the material of the infrared reflection layer is 1-30%.

[0018] The composite encapsulation film of the present application includes an infrared reflection layer and a transparent film layer stacked in sequence. When the composite encapsulation film is used as the encapsulation film on the back of a double-glass photovoltaic module, the infrared light passing through the cells of the double-glass photovoltaic module can be reflected back to the back of the cells by the infrared reflection layer for secondary utilization, thereby improving the utilization rate of infrared light by the double-glass photovoltaic module, and further improving the overall utilization rate of sunlight by the cells. Controlling the mass content of the infrared reflection material in the material of the infrared reflection layer within the above range helps to ensure the visible light transmittance of the infrared reflection layer while increasing the infrared reflectivity of the infrared reflection layer. The transparent film layer has a higher visible light transmittance than the infrared reflection layer, and the synergistic effect of the infrared reflection layer and the transparent film layer helps the composite encapsulation film to have both a high infrared reflectivity and a high visible light transmittance. At the same time, the visible light passing through the back glass can pass through the composite encapsulation film and irradiate the back of the cells for utilization, which helps to improve the light-receiving efficiency of both sides of the cells, and further helps to improve the overall power of the double-glass photovoltaic module.

[0019] In an embodiment of the present application, the above composite encapsulation film satisfies at least one of the following conditions: (1) the visible light transmittance of the infrared reflection layer is greater than 60%; (2) the infrared reflectivity of the infrared reflection layer is greater than 20%; (3) the visible light transmittance of the transparent film layer is greater than 90%; (4) the infrared reflectivity of the composite encapsulation film is 20-75%; (5) the visible light transmittance of the composite encapsulation film is 75-93%.

[0020] Controlling the visible light transmittance and the infrared reflectivity of the infrared reflection layer and the visible light transmittance of the transparent film layer within the above range is more conducive to making the composite encapsulation film take into account the utilization rates of higher infrared light and visible light.

[0021] In an embodiment of the present application, the infrared reflectivity of the above infrared reflection layer in the wavelength band of 800-2000 nm is 15-50%.

[0022] The infrared reflection layer with the infrared reflectivity in the above characteristic wavelength band helps to further improve the infrared reflectivity of the composite encapsulation film.

[0023] In an embodiment of the present application, the mass content of the infrared reflection material in the material of the infrared reflection layer is 2-10%; preferably, the material of the infrared reflection layer further includes a first auxiliary agent, and the mass ratio of the first matrix resin to the first auxiliary agent is 100: (2-5); preferably, the first auxiliary agent is selected from any one or more of a first cross-linking agent, a first co-cross-linking agent, a first light stabilizer, and a first tackifier.

[0024] If the mass content of the mid-infrared reflective material in the material of the infrared reflective layer is too high, it is not conducive to improving the visible light transmittance of the infrared reflective layer. If the mass content of the mid-infrared reflective material in the material of the infrared reflective layer is too low, it is not conducive to improving the infrared light reflectivity of the infrared reflective layer. Preferably, controlling the mass content of the mid-infrared reflective material in the material of the infrared reflective layer within the above range helps the infrared reflective layer to have both high infrared light reflectivity and high visible light transmittance. Controlling the mass ratio of the first matrix resin to the first additive within the above range helps to further improve the stability of the composite encapsulation film.

[0025] In one embodiment of the present application, the thickness of the above infrared reflective layer is 100 μm to 200 μm, specifically, it can be 100 μm, 125 μm, 150 μm, 175 μm, 200 μm, and the range values between any two values; and / or, the thickness of the transparent film layer is 100 μm to 400 μm, specifically, it can be 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, and the range values between any two values; preferably, the ratio of the thickness of the infrared reflective layer to the thickness of the transparent film layer is 1:1 to 2, specifically, it can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2, and the range values between any two ratios.

[0026] If the thickness of the infrared reflective layer is too thick, it is not conducive to the transmission of visible light. If the thickness of the infrared reflective layer is too thin, it is not conducive to improving the reflection of infrared light by the composite encapsulation film. Preferably, controlling the thickness of the infrared reflective layer within the above range helps the infrared reflective layer to have high infrared light reflectivity and high visible light transmittance. If the thickness of the transparent film layer is too thin, it is not conducive to improving the stability of the composite encapsulation film. If the thickness of the transparent film layer is too thick, it is not conducive to reducing the cost of the composite encapsulation film. Preferably, controlling the thickness of the transparent film layer within the above range helps to further improve the comprehensive performance of the composite encapsulation film. Preferably, controlling the ratio of the thickness of the infrared reflective layer to the thickness of the transparent film layer within the above range helps the infrared reflective layer to have high infrared light reflectivity and high visible light transmittance.

[0027] In order to further improve the infrared reflectivity of the infrared reflective layer and reduce the cost of the infrared reflective layer, in one embodiment of the present application, preferably, the infrared reflective material is selected from any one or more of rare earth oxides, non-rare earth metal oxides, cesium tungsten bronze, yttrium molybdate, strontium copper silicate, bismuth oxychloride, and zirconium carbide; preferably, the non-rare earth metal oxides are selected from any one or more of indium tin oxide, antimony tin oxide, tin oxide, vanadium dioxide, aluminum-doped zinc oxide, chromium oxide, and titanium oxide; and / or, the rare earth oxides are selected from any one or more of lanthanum oxide, cerium oxide, praseodymium oxide, and neodymium oxide.

[0028] In an embodiment of the present application, the above infrared reflective material is a mixture of rare earth oxides and non-rare earth metal oxides, and the mass ratio of the rare earth oxides to the non-rare earth metal oxides is 1:0.1 to 10, preferably 1:(1 to 5), and specifically can be 1:1, 1:2, 1:3, 1:4, 1:5, and the range values between any two ratios.

[0029] Due to its special electronic structure, rare earth oxides can provide an efficient reflection effect in the near-infrared band. Non-rare earth metal oxides have excellent reflection ability in the mid-infrared to far-infrared bands. Mixing the two can utilize the advantages of rare earth oxides in the near-infrared band and the reflection characteristics of non-rare earth metal oxides in the mid- and far-infrared bands, which helps to improve the infrared light reflectivity of the composite encapsulation film. Controlling the mass ratio of rare earth oxides to non-rare earth metal oxides within the above range helps to improve the mutual synergistic effect between the two, thereby further improving the infrared light reflectivity of the composite encapsulation film.

[0030] In an embodiment of the present application, the above first matrix resin is selected from any one or more of ethylene-vinyl acetate copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, silicone, and polyvinyl butyral.

[0031] Preferably controlling the type of the first matrix resin within the above range helps to improve the visible light transmittance of the infrared reflective layer.

[0032] In order to further improve the visible light transmittance of the composite encapsulation film and improve the interaction between the infrared reflective layer and the transparent film layer, in an embodiment of the present application, by weight, the material of the above transparent film layer includes 100 parts of a second matrix resin and 2 to 5 parts of an auxiliary agent; preferably, the second matrix resin is selected from any one or more of ethylene-vinyl acetate copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, silicone, and polyvinyl butyral; preferably, the second auxiliary agent is selected from any one or more of a second crosslinking agent, a second co-crosslinking agent, a second light stabilizer, and a second tackifier.

[0033] Including but not limited to, the above-mentioned first crosslinking agent and second crosslinking agent are each independently selected from any one or more of isopropyl t-butyl peroxycarbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 2-ethylhexyl t-butyl peroxycarbonate, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-amyl 2-ethylhexyl peroxycarbonate, 2,5-dimethyl 2,5-dimethyl 2,5-dimethyl 2,5-bis(benzoylperoxy)-hexane, tert-amyl peroxycarbonate, tert-butyl 3,3,5-trimethylhexanoate peroxide;

[0034] The above-mentioned first co-crosslinking agent and second co-crosslinking agent are each independently selected from any one or more of triallyl isocyanurate, trimellitic acid triallyl ester, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl)isocyanuric acid triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, trimethylolpropane tetraacrylate, bis-trimethylolpropane tetraacrylate, bis-trimethylolpropane tetramethacrylate, propoxylated pentaerythritol tetraacrylate, 2,4,6-tris(2-propenyloxy)-1,3,5-triazine, tricyclodecane dimethanol diacrylate, propoxylated neopentyl glycol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and polyethylene glycol dimethacrylate;

[0035] The above-mentioned first light stabilizer and second light stabilizer are each independently selected from any one or more of cetyl 3,5-di-tert-butyl-4-hydroxybenzoate, tris(1,2,2,6,6-pentamethyl-4-piperidyl) phosphite, bis-2,2,6,6-tetramethylpiperidinyl sebacate, bis-1-decyloxy-2,2,6,6-tetramethylpiperidin-4-ol sebacate;

[0036] The above-mentioned first tackifier and second tackifier are each independently selected from any one or more of γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, vinyltrimethoxysilane.

[0037] In another typical embodiment of the present application, a double-glass photovoltaic module is provided, which includes a front glass, a first encapsulant film, a cell, a second encapsulant film, and a back glass stacked in sequence. The second encapsulant film is the aforementioned composite encapsulant film; wherein, the infrared reflection layer of the composite encapsulant film is in contact with the cell, and the transparent film layer is in contact with the back glass.

[0038] Applying the composite encapsulant film of the present application to the back of the cell of the double-glass photovoltaic module, the infrared light passing through the cell is reflected back to the back of the cell through the composite encapsulant film of the present application for secondary utilization. At the same time, the visible light passing through the back glass can pass through the composite encapsulant film and irradiate the back of the cell for utilization, which helps to improve the light-receiving efficiency on both sides of the cell, and further helps to improve the power of the double-glass photovoltaic module.

[0039] The beneficial effects of the present application will be further described below in conjunction with embodiments.

[0040] Example 1

[0041] 100 parts by weight of ethylene-vinyl acetate (EVA) resin with a melt index of 40 g / 10 min, the content of VA in the EVA resin is 33%, 0.5 parts by weight of isopropyl percarbonate tert-butyl, 1 part by weight of trimethylolpropane trimethacrylate, 2 parts by weight of γ-aminopropyltriethoxysilane, 0.1 part by weight of bis(2,2,6,6-tetramethylpiperidin-4-yl) sebacate, lanthanum oxide and indium oxide are mixed to obtain an infrared reflection layer mixture. The mass ratio of lanthanum oxide in the infrared reflection layer mixture is 1%, and the mass ratio of indium tin oxide in the infrared reflection layer mixture is 1%; 100 parts by weight of ethylene-vinyl acetate (EVA) resin with a melt index of 40 g / 10 min, the content of VA in the EVA resin is 33%, 0.5 parts by weight of isopropyl percarbonate tert-butyl, 1 part by weight of trimethylolpropane trimethacrylate, 2 parts by weight of γ-aminopropyltriethoxysilane, 0.1 part by weight of bis(2,2,6,6-tetramethylpiperidin-4-yl) sebacate are mixed to obtain a transparent film layer mixture. The infrared reflection layer mixture and the transparent film layer mixture are co-extruded and cast into a film to obtain a composite encapsulant film. The composite encapsulant film is composed of an infrared reflection layer and a transparent film layer. The thickness of the infrared reflection layer is 150 μm, and the thickness of the transparent film layer is 300 μm.

[0042] Example 2

[0043] The difference from Example 1 is that the mass ratio of lanthanum oxide in the infrared reflection layer mixture is 5%, and the mass ratio of indium oxide in the infrared reflection layer mixture is 5%, and finally a composite encapsulant film is obtained.

[0044] Example 3

[0045] The difference from Example 1 is that the mass proportion of lanthanum oxide in the infrared reflection layer mixture is 15%, and the mass proportion of indium oxide in the infrared reflection layer mixture is 15%, and finally a composite encapsulation film is obtained.

[0046] Example 4

[0047] The difference from Example 1 is that the mass proportion of lanthanum oxide in the infrared reflection layer mixture is 0.5%, and the mass proportion of indium oxide in the infrared reflection layer mixture is 0.5%, and finally a composite encapsulation film is obtained.

[0048] Example 5

[0049] The difference from Example 1 is that when co-extrusion casting into a film, the thickness of the infrared reflection layer is controlled to be 150 μm, and the thickness of the transparent film layer is 150 μm, and finally a composite encapsulation film is obtained.

[0050] Example 6

[0051] The difference from Example 1 is that when co-extrusion casting into a film, the thickness of the infrared reflection layer is controlled to be 100 μm, and the thickness of the transparent film layer is 400 μm, and finally a composite encapsulation film is obtained.

[0052] Example 7

[0053] The difference from Example 1 is that when co-extrusion casting into a film, the thickness of the infrared reflection layer is controlled to be 50 μm, and the thickness of the transparent film layer is 450 μm, and finally a composite encapsulation film is obtained.

[0054] Example 8

[0055] The difference from Example 1 is that the mass ratio of lanthanum oxide to indium tin oxide is 1:5, and finally a composite encapsulation film is obtained.

[0056] Example 9

[0057] The difference from Example 1 is that the mass ratio of lanthanum oxide to indium tin oxide is 1:10, and finally a composite encapsulation film is obtained.

[0058] Example 10

[0059] The difference from Example 1 is that the addition of indium tin oxide is cancelled, and finally a composite encapsulation film is obtained.

[0060] Example 11

[0061] The difference from Example 1 is that 100 parts by weight of ethylene-vinyl acetate (EVA) resin with a melt index of 40 g / 10 min, the content of VA in the EVA resin being 33%, 0.5 part by weight of isopropyl peroxycarbonate tert-butyl, 1 part by weight of trimethylolpropane trimethacrylate, 2 parts by weight of γ-aminopropyltriethoxysilane, 0.1 part by weight of bis(2,2,6,6-tetramethylpiperidin-4-yl) sebacate, cerium oxide and titanium oxide are mixed to obtain an infrared reflective layer mixture. The mass proportion of lanthanum oxide in the infrared reflective layer mixture is 1%, and the mass proportion of indium tin oxide in the infrared reflective layer mixture is 1%; 100 parts by weight of ethylene-vinyl acetate (EVA) resin with a melt index of 40 g / 10 min, the content of VA in the EVA resin being 33%, 0.5 part by weight of isopropyl peroxycarbonate tert-butyl, 1 part by weight of trimethylolpropane trimethacrylate, 2 parts by weight of γ-aminopropyltriethoxysilane, 0.1 part by weight of bis(2,2,6,6-tetramethylpiperidin-4-yl) sebacate are mixed to obtain a transparent adhesive film layer mixture. The infrared reflective layer mixture and the transparent adhesive film layer mixture are co-extruded and cast into a film to obtain a composite encapsulation adhesive film. The composite encapsulation adhesive film is composed of an infrared reflective layer and a transparent adhesive film layer. The thickness of the infrared reflective layer is 150 μm, and the thickness of the transparent adhesive film layer is 300 μm.

[0062] Example 12

[0063] The difference from Example 1 is that cesium tungsten bronze is used to replace lanthanum oxide, and zirconium carbide is used to replace indium tin oxide, and finally a composite encapsulation adhesive film is obtained.

[0064] Comparative Example 1

[0065] The difference from Example 1 is that the addition of lanthanum oxide and indium tin oxide is cancelled, and finally a composite encapsulation adhesive film is obtained.

[0066] Comparative Example 2

[0067] The difference from Example 1 is that the mass proportion of lanthanum oxide in the infrared reflective layer mixture is 0.1%, and the mass proportion of indium oxide in the infrared reflective layer mixture is 0.1%, and finally a composite encapsulation adhesive film is obtained.

[0068] Comparative Example 3

[0069] The difference from Example 1 is that the mass proportion of lanthanum oxide in the infrared reflective layer mixture is 20%, and the mass proportion of indium oxide in the infrared reflective layer mixture is 20%, and finally a composite encapsulation adhesive film is obtained.

[0070] Performance Test

[0071] Visible light transmittance: The test is carried out with reference to the test method provided in GB / T 29848-2013.

[0072] Infrared light reflectivity: The test was carried out with reference to the test method provided in Q / HZF003 - 2013.

[0073] Back surface power of double - glass photovoltaic module: The test was carried out with reference to the test method provided in "IEC61215".

[0074] The visible light transmittance, infrared light reflectivity, and light reflectivity in the wavelength range of 800 - 2000 nm of the infrared reflection layer in the composite encapsulation film prepared in the examples and comparative examples were tested. The visible light transmittance of the transparent film layer in the composite encapsulation film prepared in the examples and comparative examples was tested. The infrared light reflectivity and visible light transmittance of the composite encapsulation film prepared in the examples and comparative examples were tested. The composite encapsulation film prepared in the examples and comparative examples was assembled with battery cells and glass into a double - glass photovoltaic module, and the back surface power of the double - glass photovoltaic module was tested. The above test results are shown in Table 1.

[0075] Table 1

[0076]

[0077] From the above description, it can be seen that the above - mentioned embodiments of the present invention achieve the following technical effects:

[0078] The composite encapsulation film of the present application includes an infrared reflection layer and a transparent film layer stacked in sequence. When the composite encapsulation film is used as the encapsulation film on the back surface of a double - glass photovoltaic module, the infrared light passing through the battery cells of the double - glass photovoltaic module can be reflected back to the back surface of the battery cells under the action of the infrared reflection layer for secondary utilization, thereby improving the utilization rate of infrared light by the double - glass photovoltaic module, and further improving the overall utilization rate of sunlight by the battery cells. Controlling the mass content of the infrared reflection material in the material of the infrared reflection layer within the above range helps to ensure the visible light transmittance of the infrared reflection layer while increasing the infrared light reflectivity of the infrared reflection layer. The transparent film layer has a higher visible light transmittance than the infrared reflection layer. The synergistic effect of the infrared reflection layer and the transparent film layer helps the composite encapsulation film to have both a high infrared light reflectivity and a high visible light transmittance. At the same time, the visible light passing through the back - surface glass can pass through the composite encapsulation film and irradiate the back surface of the battery cells for utilization, thereby helping to improve the light - receiving efficiency of both sides of the battery cells, and further helping to improve the overall power of the double - glass photovoltaic module.

[0079] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A composite encapsulation film, characterized in that, The composite encapsulation film includes an infrared reflection layer and a transparent film layer stacked in sequence; the material of the infrared reflection layer includes an infrared reflection material and a first matrix resin, and the mass content of the infrared reflection material in the infrared reflection layer is 1-30%.

2. The composite encapsulation film according to claim 1, wherein The composite encapsulation film satisfies at least one of the following conditions: (1) the visible light transmittance of the infrared reflection layer is greater than 60%; (2) the infrared reflectance of the infrared reflection layer is greater than 20%; (3) the visible light transmittance of the transparent film layer is greater than 90%; (4) the infrared reflectance of the composite encapsulation film is 20-75%; (5) the visible light transmittance of the composite encapsulation film is 75-93%.

3. The composite encapsulation film according to claim 1 or 2, characterized in that, The infrared reflectance of the infrared reflection layer in the wavelength band of 800-2000 nm is 15-50%.

4. The composite encapsulation film according to any one of claims 1 to 3, characterized in that, The mass content of the infrared reflection material in the infrared reflection layer is 2-10%; preferably, the material of the infrared reflection layer further includes a first auxiliary agent, and the mass ratio of the first matrix resin to the first auxiliary agent is 100:(2-5); preferably, the first auxiliary agent is selected from any one or more of a first crosslinking agent, a first co-crosslinking agent, a first light stabilizer, and a first tackifier.

5. The composite encapsulation film according to any one of claims 1 to 4, characterized in that, The thickness of the infrared reflection layer is 100 μm-200 μm; and / or, the thickness of the transparent film layer is 100 μm-400 μm; preferably, the ratio of the thickness of the infrared reflection layer to the thickness of the transparent film layer is 1:1-2.

6. The composite encapsulation film according to any one of claims 1 to 5, characterized in that, The infrared reflection material is selected from any one or more of rare earth oxides, non-rare earth metal oxides, cesium tungsten bronze, yttrium molybdate, strontium copper silicate, bismuth oxychloride, and zirconium carbide; Preferably, the non-rare earth metal oxide is selected from any one or more of indium tin oxide, antimony tin oxide, tin oxide, vanadium dioxide, aluminum-doped zinc oxide, chromium oxide, and titanium oxide.

7. The composite encapsulation film according to claim 6, wherein, The infrared reflection material is a mixture of the rare earth oxide and the non-rare earth metal oxide, and the mass ratio of the rare earth oxide to the non-rare earth metal oxide is 1:0.1-10, preferably 1:(1-5).

8. The composite encapsulation film according to any one of claims 1 to 7, characterized in that, The first matrix resin is selected from any one or more of ethylene-vinyl acetate copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, silicone, and polyvinyl butyral.

9. The composite encapsulation film according to any one of claims 1 to 8, characterized in that, By weight, the material of the transparent film layer includes 100 parts of a second matrix resin and 2-5 parts of a second auxiliary agent; preferably, the second matrix resin is selected from any one or more of ethylene-vinyl acetate copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, silicone, and polyvinyl butyral; preferably, the second auxiliary agent is selected from any one or more of a second crosslinking agent, a second co-crosslinking agent, a second light stabilizer, and a second tackifier.

10. A double-glass photovoltaic module, comprising a front glass, a first encapsulation adhesive film, a battery cell, a second encapsulation adhesive film, and a back glass stacked in sequence, characterized in that, The second encapsulation film is the composite encapsulation film according to any one of claims 1 to 9; wherein, the infrared reflection layer of the composite encapsulation film is in contact with the battery chip, and the transparent film layer is in contact with the back glass.

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