Adhesive film, method for producing the same, and photovoltaic module

Abstract

The application provides a kind of adhesive film, its preparation method and photovoltaic module.The preparation method comprises: the first base resin, the first initiator and the light diffuser are mixed to obtain the light diffusion layer ingredients;The second base resin, the second initiator and the long afterglow material are mixed to obtain the long afterglow layer ingredients;The third base resin, the third initiator and the white filler are mixed to obtain the white filler layer ingredients;The light diffusion layer ingredients, the long afterglow layer ingredients and the white filler layer ingredients are melt co-extruded to obtain the adhesive film.The adhesive film with the above structure prepared by the above method has high luminous or transmittance, and its application in the preparation of photovoltaic module can greatly improve the photoelectric conversion efficiency of photovoltaic module, reduce the cost of power station, and improve the reliability of product.

Description

Technical Field

[0001] This invention relates to the field of photovoltaics, and more specifically, to an adhesive film, its preparation method, and a photovoltaic module. Background Technology

[0002] In order to reduce costs, improving the power generation efficiency of solar photovoltaic modules has become an inevitable path for all solar panel manufacturers to develop and implement.

[0003] Currently, there are several main ways to improve the power generation efficiency of crystalline silicon solar cells:

[0004] (1) Use a transparent film with a white backsheet. The white backsheet reflects the light between the cells and between the strings onto the front and back of the solar cells. However, this method has a low power gain due to the low reflectivity of the backsheet.

[0005] (2) A white film and transparent glass are used on the back of the battery. Since the white film is close to the battery cell, the distance between the reflective layer and the back of the battery cell is reduced, which reduces the reflection angle. As a result, the reflected light obtained by the battery on the back is reduced, and the power gain obtained is not significant.

[0006] (3) A photoconversion agent film is used on the front of the battery. This can convert ultraviolet light into visible light to increase the power generation efficiency of photovoltaic modules. However, due to its high content, the overall light transmittance of the film will decrease, thus the overall power gain of the battery is not significant.

[0007] Existing literature CN102140314A provides an EVA film with high reflectivity, which directly adds inorganic reflective materials such as titanium dioxide during the preparation process. This may cause cross-melting of the upper and lower layers of the film, affecting the light transmittance of the upper transparent film. Furthermore, it can only generate electricity during the day, resulting in poor overall power generation efficiency.

[0008] Existing literature CN101882634A provides a solar cell that can operate at night. Although it can generate electricity effectively at night, the long afterglow material it uses is placed in the front layer. The energy it generates at night comes from sacrificing the light absorbed by the long afterglow material during the day. In fact, its module power gain is not large or even reduced.

[0009] Existing literature CN102863916A provides a POE spectral conversion solar cell encapsulation film, which can effectively convert ultraviolet and infrared light into visible light. However, it uses a high content of light conversion particles, which will lead to a decrease in the light transmittance of the film, and therefore does not significantly improve the overall power gain of the cell. Summary of the Invention

[0010] The main objective of this invention is to provide an adhesive film, its preparation method, and a photovoltaic module to solve the problem of low power generation efficiency of existing solar photovoltaic modules.

[0011] To achieve the above objectives, according to one aspect of the present invention, a method for preparing an adhesive film is provided, the method comprising: mixing a first matrix resin, a first initiator, and a light diffusing agent to obtain a light diffusing layer formulation; mixing a second matrix resin, a second initiator, and a long afterglow material to obtain a long afterglow layer formulation; mixing a third matrix resin, a third initiator, and a white filler to obtain a white filler layer formulation; and performing melt co-extrusion of the light diffusing layer formulation, the long afterglow layer formulation, and the white filler layer formulation to obtain an adhesive film.

[0012] Furthermore, the light diffusion layer formulation further includes: a first crosslinking agent and a first tackifier; preferably, by weight, the light diffusion layer formulation includes 100 parts of a first matrix resin, 0.05 to 1.5 parts of a first initiator, 0.5 to 3 parts of a first crosslinking agent, 0.1 to 5 parts of a first tackifier and 0.1 to 5 parts of a light diffusion agent.

[0013] Furthermore, the light diffusing agent is an organosilicon resin, preferably a vinyl silane and / or an aromatic silane, with a particle size of 1–10 μm.

[0014] Furthermore, the long afterglow layer formulation also includes a second crosslinking agent and a second tackifier; preferably, by weight, the long afterglow layer formulation includes 100 parts of a second matrix resin, 0.05 to 1.5 parts of a second initiator, 0.5 to 3 parts of a second crosslinking agent, 0.1 to 5 parts of a second tackifier, and 0.5 to 5 parts of a long afterglow material.

[0015] Furthermore, the long afterglow material is an alkaline earth aluminate, preferably SrAl2O4:Eu or Sr4Al. 14 O 25 Eu or CaAl2O4:Eu, with a particle size of 5–100 nm.

[0016] Furthermore, the white filler layer formulation also includes a third crosslinking agent, a third tackifier, and a superdispersant; preferably, by weight, the white filler layer formulation includes 100 parts of a third matrix resin, 0.05 to 1.5 parts of a third initiator, 0.5 to 3 parts of a third crosslinking agent, 0.1 to 5 parts of a third tackifier, 0.5 to 10 parts of white filler, and 0.1 to 1 part of superdispersant.

[0017] Furthermore, the white filler is selected from one or more of the group consisting of titanium dioxide, barium sulfate, calcium carbonate, mica and talc; the superdispersant is a hydroxyl-terminated aliphatic hyperbranched polyester.

[0018] Further, the first matrix resin, the second matrix resin, and the third matrix resin are each independently selected from one or more of the group consisting of polyolefin elastomers, ethylene-vinyl acetate copolymers, or polyvinyl butyral; the first initiator, the second initiator, and the third initiator are each independently selected from free radical thermal initiators, preferably, the first initiator, the second initiator, and the third initiator are each independently selected from tert-butyl peroxycarbonate isopropyl ester, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, and tert-butyl peroxycarbonate-2-ethylhexyl ester. 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexane, 1,1-bis(tert-pentylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-pentylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-amyl peroxide, and tert-amyl peroxide; the first, second, and third co-crosslinking agents are multifunctional acrylates with ≥2 functional groups; preferably, the first, second, and third co-crosslinking agents are each independently selected from tri(2- Hydroxyethyl) isocyanurate triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, propionyl glycerol triacrylate, ethoxylated glycerol triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, trimethylolpropane tetraacrylate, bis(trimethylolpropane tetraacrylate), bis(trimethylolpropane tetramethacrylate), propionyl glycerol tetraacrylate, 2,4,6-tris(2-propenyloxy)-1,3,5-triazine, tri... The tackifying resin comprises one or more of the following groups: cyclodecanediethanol diacrylate, propoxylated neopentyl glycol diacrylate, and ethoxylated bisphenol A diacrylate; the first tackifying resin, the second tackifying resin, and the third tackifying resin are each independently selected from silane coupling agents; preferably, the first tackifying resin, the second tackifying resin, and the third tackifying resin are each independently selected from one or more of the following groups: γ-aminopropyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, vinyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

[0019] Furthermore, the thickness ratio of the light diffusion layer, the long afterglow layer, and the white filler layer is 1:(0.2~5):(0.4~10).

[0020] Another aspect of this application provides an adhesive film, which is prepared by the above-described preparation method.

[0021] Another aspect of this application provides a photovoltaic module, including an encapsulating film comprising the aforementioned encapsulating film.

[0022] By applying the technical solution of this invention, the white filler layer in the white reflective layer can reflect incident light, while the light diffusion layer can diffuse the light reflected by the white reflective layer in all directions during the day, increasing light scattering and reflectivity; the long afterglow layer can continue to emit light at night, compensating for the defect that the light scattering layer cannot emit light at night. Due to the above factors, the encapsulant film with the above structure prepared by the above method has high luminescence or light transmittance. Applying it to the preparation of photovoltaic modules can greatly improve the photoelectric conversion efficiency of photovoltaic modules, reduce the cost of power plants, and improve product reliability. Attached Figure Description

[0023] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0024] Figure 1 A schematic diagram of the structure of the three-layer co-extruded film prepared according to Example 1 of this application is shown; and

[0025] Figure 2 A schematic diagram of the structure of a photovoltaic module containing the three-layer co-extruded film prepared in Example 1 of this application is shown. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0027] As described in the background section, existing solar photovoltaic modules suffer from low power generation efficiency. To address this technical problem, this application provides a method for preparing an encapsulant film. The method includes: mixing a first matrix resin, a first initiator, and a light diffusing agent to obtain a light diffusing layer formulation; mixing a second matrix resin, a second initiator, and a long afterglow material to obtain a long afterglow layer formulation; mixing a third matrix resin, a third initiator, and a white filler to obtain a white filler layer formulation; and melt-co-extrudeing the light diffusing layer formulation, the long afterglow layer formulation, and the white filler layer formulation to obtain an encapsulant film.

[0028] The white filler layer in the white reflective layer reflects incident light, while the light diffusion layer diffuses the light reflected by the white reflective layer in all directions during the day, increasing light scattering and reflectivity. The long afterglow layer continues to emit light at night, compensating for the light scattering layer's inability to emit light at night. Due to these factors, the encapsulant film with the above structure, prepared using this method, exhibits high luminescence or light transmittance. Applying it to the fabrication of photovoltaic modules can significantly improve the photoelectric conversion efficiency of photovoltaic modules, reduce power plant costs, and enhance product reliability.

[0029] Preferably, the white filler layer in the above-mentioned adhesive film is located near the electromagnetic sheet.

[0030] To improve the overall performance of the light diffusion layer, in a preferred embodiment, the light diffusion layer formulation further includes a first co-crosslinking agent and a first tackifier. The addition of the first co-crosslinking agent helps to increase the degree of crosslinking of the light diffusion layer, while the addition of the first tackifier helps to increase both the degree of crosslinking of the light diffusion layer and the adhesion performance between the light diffusion layer and other layers.

[0031] The components in the above-mentioned light diffusion layer formulation can be freely combined. In a preferred embodiment, the light diffusion layer formulation, by weight, includes 100 parts of a first resin oligomer, 0.05 to 1.5 parts of a first initiator, 0.5 to 3 parts of a first crosslinking agent, 0.1 to 5 parts of a first tackifier, and 0.1 to 5 parts of a light diffusing agent. The amounts of each component in the light diffusion layer formulation are not limited to the above ranges. Limiting them within these ranges allows the components to exert a synergistic effect, further improving the crosslinking degree, light diffusivity, transmittance, and adhesion performance of the formed light diffusion layer, thereby improving the photoelectric conversion efficiency of the resulting photovoltaic module.

[0032] The light diffusing agent can achieve the above-mentioned effects, and its type is not specifically limited. In a preferred embodiment, the light diffusing agent is an organosilicon resin, more preferably a vinyl silane and / or an aromatic silane, with a particle size of 1-10 μm. Compared with other light diffusing agents, the above-mentioned types are beneficial to further improve the light diffusivity and light transmittance of the light diffusing layer.

[0033] In a preferred embodiment, the long afterglow layer formulation further includes a second co-crosslinking agent and a second tackifier. The addition of the second co-crosslinking agent is beneficial for improving the crosslinking degree of the light diffusion layer, while the addition of the second tackifier is beneficial for both improving the crosslinking degree of the light diffusion layer and improving the adhesion performance between the light diffusion layer and other layers.

[0034] The components in the above-mentioned long afterglow layer formulation can be freely combined. In a preferred embodiment, the long afterglow layer formulation comprises, by weight, 100 parts of a second resin oligomer, 0.05 to 1.5 parts of a second initiator, 0.5 to 3 parts of a second co-crosslinking agent, 0.1 to 5 parts of a second tackifier, and 0.5 to 5 parts of a long afterglow material. Limiting the amounts of each component in the long afterglow layer formulation to the above range allows the components to exert a synergistic effect, further improving the crosslinking degree, adhesion performance, and nighttime luminous efficiency of the formed long afterglow layer, thereby increasing the power generation of the resulting photovoltaic module.

[0035] Long-afterglow materials are materials that can absorb energy and continue to emit light after excitation ceases. In the aforementioned films, the long-afterglow material only needs to achieve the above-mentioned effect; its specific type is not limited. In a preferred embodiment, the long-afterglow material is an alkaline earth aluminate. Compared to other long-afterglow materials, alkaline earth aluminates have higher luminous efficiency, and using them to prepare the long-afterglow layer can greatly improve the luminous efficiency and lifespan of the long-afterglow layer. The aforementioned alkaline earth aluminate layer includes, but is not limited to, SrAl2O4:Eu and Sr4Al. 14 O 25 Eu or CaAl2O4:Eu, with a particle size of 5–100 nm.

[0036] In a preferred embodiment, the white filler layer formulation further includes a third co-crosslinking agent, a third tackifier, and a superdispersant. The addition of the third co-crosslinking agent helps to improve the crosslinking degree of the light diffusion layer; the addition of the third tackifier helps to improve the crosslinking degree of the white filler layer and also helps to improve the adhesion between the white filler layer and other layers; the addition of the superdispersant helps to improve the dispersion performance of the white filler in the white filler layer, thereby further improving the light reflection efficiency of the white filler layer.

[0037] The components in the above-mentioned white filler layer formulation can be freely combined. In a preferred embodiment, the white filler layer formulation, by weight, includes 100 parts of a third resin oligomer, 0.05 to 1.5 parts of a third initiator, 0.5 to 3 parts of a third co-crosslinking agent, 0.1 to 5 parts of a third tackifier, 0.5 to 10 parts of white filler, and 0.1 to 1 part of a superdispersant. Limiting the amounts of each component in the white filler layer formulation to the above range allows the components to exert a synergistic effect, further improving the crosslinking degree, adhesion performance, and light reflectivity of the formed white filler layer, significantly reducing the risk of microcracks, whitening, and low adhesion when in contact with the solar cell.

[0038] In a preferred embodiment, the white filler includes, but is not limited to, one or more of the group consisting of titanium dioxide, barium sulfate, calcium carbonate, mica, and talc. All of the above-mentioned filler layers are made from fillers containing coupling groups, which makes the preparation of white filler layers more conducive to further improving the dispersion uniformity of the white filler, thereby further improving the reflectivity of the film.

[0039] The aforementioned superdispersant can be selected from commonly used types in the art. In a preferred embodiment, the superdispersant includes, but is not limited to, terminal hydroxyl aliphatic hyperbranched polyesters. These superdispersants possess a unique branched molecular structure, with no entanglement between molecules, and contain a large number of end groups. Compared to other types of superdispersants, they are more beneficial for further dispersing the white filler, thereby further improving the light reflectance properties of the white filler layer. Preferably, the aforementioned superdispersant includes, but is not limited to, one or more of the group consisting of HyPer H10, HyPer H20, Boltorn H20, Boltorn H30, and Boltorn H40.

[0040] The first matrix resin, second matrix resin, and third matrix resin described above can be selected from commonly used resin materials in the art. In a preferred embodiment, the first matrix resin, second matrix resin, and third matrix resin are each independently selected from one or more of the group consisting of POE (polyolefin elastomer), ethylene-vinyl acetate copolymer (EVA), or polyvinyl butyral (PVB).

[0041] The first, second, and third initiators mentioned above can be selected from those commonly used in the art, such as free radical thermal initiators. More preferably, the first, second, and third initiators are each independently selected from one or more of the following groups: tert-butyl peroxycarbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-butyl peroxycarbonate-2-ethylhexyl ester, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,1-bis(tert-pentylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-pentylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-pentyl peroxycarbonate, and tert-pentyl peroxycarbonate.

[0042] In the preparation process of the above-mentioned adhesive film, the types of the first, second, and third co-crosslinking agents are not specifically limited, as long as they can achieve the purpose of improving the degree of crosslinking. In a preferred embodiment, the first, second, and third co-crosslinking agents are multifunctional acrylates, and the number of functional groups is ≥2. More preferably, the agent is selected independently from one or more of the following groups: tri(2-hydroxyethyl)isocyanurate triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, trimethylolpropane trimethacrylate, 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, tricyclodecanediethanol diacrylate, propoxylated neopentyl glycol diacrylate, and ethoxylated bisphenol A diacrylate. Compared to other types of co-crosslinking agents, the above-mentioned co-crosslinking agents have multiple functional groups, thus using these co-crosslinking agents is beneficial to further improve the crosslinking degree of the film, thereby improving its photoelectric conversion performance.

[0043] Tackifiers are used to improve the adhesion between the layers of the adhesive film and between the adhesive film and the substrate material. Preferably, the first tackifying resin, the second tackifying resin, and the third tackifying resin are each independently selected from silane coupling agents. Compared with other tackifying resins, silane coupling agents have better coupling properties, and therefore, using them as tackifying resins is beneficial to improving the adhesive properties of the adhesive film and its adhesion to the substrate material. More preferably, the first tackifying resin, the second tackifying resin, and the third tackifying resin are each independently selected from one or more of the group consisting of γ-aminopropyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, vinyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

[0044] The white filler layer in the white reflective layer reflects incident light, while the light diffusion layer diffuses the light reflected by the white reflective layer in all directions during the day, increasing light scattering and reflectivity. The long-afterglow layer continues to emit light at night, compensating for the light scattering layer's inability to emit light at night. In a preferred embodiment, the thickness ratio of the light diffusion layer, the long-afterglow layer, and the white filler layer is 1:(0.2–5):(0.4–10). This thickness ratio includes, but is not limited to, the range described above. Limiting it to this range further optimizes the photoelectric conversion performance of the three material layers, thereby further improving the overall performance of the film.

[0045] In a preferred embodiment, the step of melt co-extruding the light diffusion layer material, the long afterglow layer material, and the white filler layer material includes: granulating the light diffusion layer material, the long afterglow layer material, and the white filler layer material separately, and then extruding them at 90°C through a three-layer co-extrusion extruder, and obtaining the extrudate through casting, cooling, slitting, and winding processes.

[0046] Another aspect of this application provides an adhesive film, which is prepared by the above-described preparation method.

[0047] The white filler layer in the white reflective layer reflects incident light, while the light diffusion layer diffuses the light reflected by the white reflective layer in all directions during the day, increasing light scattering and reflectivity. The long afterglow layer continues to emit light at night, compensating for the light scattering layer's inability to emit light at night. Due to these factors, the encapsulant film with the above structure, prepared using this method, exhibits high luminescence or light transmittance. Applying it to the fabrication of photovoltaic modules can significantly improve the photoelectric conversion efficiency of photovoltaic modules, reduce power plant costs, and enhance product reliability.

[0048] Another aspect of this application provides a photovoltaic module, including an encapsulating film, the encapsulating film including the aforementioned encapsulating film provided in this application.

[0049] Because the above-mentioned films have high light emission or light transmittance, their application in the preparation of photovoltaic modules can greatly improve the photoelectric conversion efficiency of photovoltaic modules, reduce the cost of power plants, and improve the reliability of products.

[0050] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0051] Example 1

[0052] By weight, 0.5 parts of organosilicon light diffusing agent (phenyl silane, Shin-Etsu KMP-590, Japan) and 10 parts of POE were granulated in a twin-screw granulator at 120°C to prepare light diffusing masterbatch; 10.5 parts of light diffusing masterbatch, 90 parts of POE, 0.5 parts of first initiator (2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 1 part of first co-crosslinking agent (trimethylolpropane triacrylate), and 1 part of first tackifying resin (γ-(2,3-epoxypropoxy)propyltrimethoxysilane) were mixed evenly to obtain the light diffusing layer formulation.

[0053] Three parts of long afterglow powder (SrAl2O4:Eu, Lumin Technology PL0-6B) and ten parts of POE were granulated in a twin-screw granulator at 120℃ to prepare long afterglow masterbatch; 0.5 parts of a second initiator (2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 1 part of a second co-crosslinking agent (trimethylolpropane triacrylate), and 1 part of a second tackifying resin (γ-(2,3-epoxypropoxy)propyltrimethoxysilane) were added to 13 parts of long afterglow masterbatch and 90 parts of POE and mixed evenly to obtain the long afterglow layer formulation.

[0054] White ultradispersible masterbatch was prepared by granulating 0.2 parts of ultradispersant (Wuhan hyperbranched resin HyPer H20), 5 parts of white filler (titanium dioxide), and 20 parts of POE in a twin-screw granulator at 120℃. Then, 0.5 parts of a third initiator (2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 1 part of a third co-crosslinking agent (trimethylolpropane triacrylate), and 1 part of a third tackifying resin (γ-(2,3-epoxypropoxy)propyltrimethoxysilane) were added to 25.2 parts of the white ultradispersible masterbatch and 80 parts of POE and mixed evenly to obtain the white ultradispersible layer formulation.

[0055] The light diffusion layer, long afterglow layer, and white ultra-dispersed layer are extruded at 90℃ using a three-layer co-extrusion extruder. The extrudate is then cast, cooled, slit, and wound to obtain a high-power photovoltaic module encapsulation film with a light diffusion layer as the top layer, a long afterglow layer as the middle layer, and a white ultra-dispersed layer as the bottom layer. The thickness ratio of the light diffusion layer, long afterglow layer, and white ultra-dispersed layer is 1:0.5:2. A schematic diagram of the film structure is shown below. Figure 1 A schematic diagram of the structure of the obtained photovoltaic module is shown below. Figure 2 .

[0056] Example 2

[0057] The difference from Example 1 is the composition of the light diffusion layer formulation. Specifically, 5 parts by weight of organosilicon light diffusion agent (Shin-Etsu KMP-590, Japan) and 10 parts by weight of POE were granulated in a twin-screw granulator at 120°C to prepare a light diffusion masterbatch. 15 parts by weight of the light diffusion masterbatch, 90 parts by weight of POE, 0.05 parts by weight of the first initiator (2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 3 parts by weight of the first co-crosslinking agent (trimethylolpropane triacrylate), and 0.1 parts by weight of the first tackifying resin (γ-(2,3-epoxypropoxy)propyltrimethoxysilane) were mixed uniformly to obtain the light diffusion layer formulation. Everything else was the same as in Example 1. The thickness ratio of the light diffusion layer, the long afterglow layer, and the white ultradispersed layer was 1:0.5:2.

[0058] Example 3

[0059] The difference from Example 1 is the composition of the light diffusion layer formulation. Specifically, 0.1 parts by weight of organosilicon light diffusion agent (Shin-Etsu KMP-590, Japan) and 10 parts by weight of POE were granulated in a twin-screw granulator at 120°C to prepare a light diffusion masterbatch. 10.1 parts by weight of the light diffusion masterbatch, 90 parts by weight of POE, 1.5 parts by weight of the first initiator (2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 0.5 parts by weight of the first co-crosslinking agent (trimethylolpropane triacrylate), and 5 parts by weight of the first tackifying resin (γ-(2,3-epoxypropoxy)propyltrimethoxysilane) were mixed uniformly to obtain the light diffusion layer formulation. Everything else was the same as in Example 1. The thickness ratio of the light diffusion layer, the long afterglow layer, and the white ultradispersed layer was 1:0.5:2.

[0060] Example 4

[0061] The difference from Example 1 is the composition of the light diffusion layer formulation. Specifically, 4 parts by weight of organosilicon light diffusion agent (Shin-Etsu KMP-590, Japan) and 10 parts by weight of POE were granulated in a twin-screw granulator at 120°C to prepare a light diffusion masterbatch. 14 parts by weight of the light diffusion masterbatch, 90 parts by weight of POE, 1 part by weight of the first initiator (2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 2 parts by weight of the first co-crosslinking agent (trimethylolpropane triacrylate), and 4 parts by weight of the first tackifying resin (γ-(2,3-epoxypropoxy)propyltrimethoxysilane) were mixed uniformly to obtain the light diffusion layer formulation. Everything else was the same as in Example 1. The thickness ratio of the light diffusion layer, the long afterglow layer, and the white ultradispersed layer was 1:0.5:2.

[0062] Example 5

[0063] The difference from Example 1 is the composition of the light diffusion layer formulation. Specifically, 7 parts by weight of organosilicon light diffusion agent (Shin-Etsu KMP-590, Japan) and 10 parts by weight of POE were granulated in a twin-screw granulator at 120°C to prepare a light diffusion masterbatch. 17 parts by weight of the light diffusion masterbatch, 90 parts by weight of POE, 2 parts by weight of the first initiator (2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 0.3 parts by weight of the first co-crosslinking agent (trimethylolpropane triacrylate), and 6 parts by weight of the first tackifying resin (γ-(2,3-epoxypropoxy)propyltrimethoxysilane) were mixed uniformly to obtain the light diffusion layer formulation. Everything else was the same as in Example 1. The thickness ratio of the light diffusion layer, the long afterglow layer, and the white ultradispersed layer was 1:0.5:2.

[0064] Example 6

[0065] The difference from Example 1 is the composition of the long afterglow layer formulation. Specifically, 5 parts of long afterglow powder (Lumin Technology PL0-6B) and 10 parts of POE were granulated in a twin-screw granulator at 120°C to prepare long afterglow masterbatch; 0.05 parts of a second initiator (2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 3 parts of a second co-crosslinking agent (trimethylolpropane triacrylate), and 0.1 parts of a second tackifying resin (γ-(2,3-epoxypropoxy)propyltrimethoxysilane) were added to 15 parts of the long afterglow masterbatch and 90 parts of POE and mixed evenly to obtain the long afterglow POE layer formulation. The thickness ratio of the light diffusion layer, the long afterglow layer, and the white ultradispersed layer was 1:0.5:2.

[0066] Example 7

[0067] The difference from Example 1 is the composition of the long afterglow layer formulation. Specifically, 0.5 parts of long afterglow powder (Lumin Technology PL0-6B) and 10 parts of POE were granulated in a twin-screw granulator at 120°C to prepare long afterglow masterbatch. Then, 1.5 parts of a second initiator (2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 0.5 parts of a second co-crosslinking agent (trimethylolpropane triacrylate), and 5 parts of a second tackifying resin (γ-(2,3-epoxypropoxy)propyltrimethoxysilane) were added to 10.5 parts of the long afterglow masterbatch and 90 parts of POE and mixed evenly to obtain the long afterglow POE layer formulation. The thickness ratio of the light diffusion layer, long afterglow layer, and white ultradispersed layer was 1:0.5:2.

[0068] Example 8

[0069] The difference from Example 1 is the composition of the long afterglow layer formulation. Specifically, 1 part of long afterglow powder (Lumin Technology PL0-6B) and 10 parts of POE were granulated in a twin-screw granulator at 120°C to prepare long afterglow masterbatch; 1 part of a second initiator (2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 2 parts of a second co-crosslinking agent (trimethylolpropane triacrylate), and 4 parts of a second tackifying resin (γ-(2,3-epoxypropoxy)propyltrimethoxysilane) were added to 11 parts of the long afterglow masterbatch and 90 parts of POE and mixed evenly to obtain the long afterglow POE layer formulation. The thickness ratio of the light diffusion layer, the long afterglow layer, and the white ultradispersed layer was 1:0.5:2.

[0070] Example 9

[0071] The difference from Example 1 is the composition of the long afterglow layer formulation. Specifically, 6 parts of long afterglow powder (Lumin Technology PL0-6B) and 10 parts of POE were granulated in a twin-screw granulator at 120℃ to prepare long afterglow masterbatch; 2 parts of a second initiator (2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 0.3 parts of a second co-crosslinking agent (trimethylolpropane triacrylate), and 5 parts of a second tackifying resin (γ-(2,3-epoxypropoxy)propyltrimethoxysilane) were added to 16 parts of the long afterglow masterbatch and 90 parts of POE and mixed evenly to obtain the long afterglow POE layer formulation. The thickness ratio of the light diffusion layer, the long afterglow layer, and the white ultradispersed layer was 1:0.5:2.

[0072] Example 10

[0073] The difference from Example 1 is that the composition of the white filler layer is different. Specifically:

[0074] White ultradispersible masterbatch was prepared by granulation of 0.1 parts of ultradispersant (Wuhan hyperbranched resin HyPer H20), 10 parts of white filler (titanium dioxide), and 20 parts of POE in a twin-screw granulator at 120℃. Then, 0.05 parts of a third initiator (2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 3 parts of a third co-crosslinking agent (trimethylolpropane triacrylate), and 0.1 parts of a third tackifying resin (γ-(2,3-epoxypropoxy)propyltrimethoxysilane) were added to 30.1 parts of the white ultradispersible masterbatch and 80 parts of POE and mixed thoroughly to obtain white ultradispersible POE material. The thickness ratio of the light diffusion layer, the long afterglow layer, and the white ultradispersible layer was 1:0.5:2.

[0075] Example 11

[0076] The difference from Example 1 is that the composition of the white filler layer is different. Specifically:

[0077] A white ultradispersible masterbatch was prepared by granulating 1 part of ultradispersant (Wuhan hyperbranched resin HyPer H20), 0.5 parts of white filler (titanium dioxide), and 20 parts of POE in a twin-screw granulator at 120℃. Then, 1.5 parts of a third initiator (2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 0.5 parts of a third co-crosslinking agent (trimethylolpropane triacrylate), and 5 parts of a third tackifying resin (γ-(2,3-epoxypropoxy)propyltrimethoxysilane) were added to 31.5 parts of the white ultradispersible masterbatch and 80 parts of POE and mixed thoroughly to obtain a white ultradispersible POE material. The thickness ratio of the light diffusion layer, the long afterglow layer, and the white ultradispersible layer was 1:0.5:2.

[0078] Example 12

[0079] The difference from Example 1 is that the composition of the white filler layer is different. Specifically:

[0080] White ultradispersible masterbatch was prepared by granulation of 0.6 parts of ultradispersant (Wuhan hyperbranched resin HyPer H20), 8 parts of white filler (titanium dioxide), and 20 parts of POE in a twin-screw granulator at 120℃. Then, 1 part of a third initiator (2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 2 parts of a third co-crosslinking agent (trimethylolpropane triacrylate), and 3 parts of a third tackifying resin (γ-(2,3-epoxypropoxy)propyltrimethoxysilane) were added to 28.6 parts of the white ultradispersible masterbatch and 80 parts of POE and mixed thoroughly to obtain white ultradispersible POE material. The thickness ratio of the light diffusion layer, the long afterglow layer, and the white ultradispersible layer was 1:0.5:2.

[0081] Example 13

[0082] The difference from Example 1 is that the composition of the white filler layer is different. Specifically:

[0083] White ultradispersible masterbatch was prepared by granulation of 2 parts ultradispersant (Wuhan hyperbranched resin HyPer H20), 12 parts white filler (titanium dioxide), and 20 parts POE in a twin-screw granulator at 120℃. Then, 2 parts of a third initiator (2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 0.3 parts of a third co-crosslinking agent (trimethylolpropane triacrylate), and 4 parts of a third tackifying resin (γ-(2,3-epoxypropoxy)propyltrimethoxysilane) were added to 34 parts of the white ultradispersible masterbatch and 80 parts of POE and mixed thoroughly to obtain white ultradispersible POE material. The thickness ratio of the light diffusion layer, the long afterglow layer, and the white ultradispersible layer was 1:0.5:2.

[0084] Example 14

[0085] The difference from Example 13 is that no superdispersant was added to the white filler layer.

[0086] Example 15

[0087] The difference from Example 13 is that no third crosslinking agent and third tackifying resin were added to the white filler layer formulation.

[0088] Comparative Example 1

[0089] The difference from Example 1 is that the co-extruded film does not contain a light diffusion layer; otherwise, it is the same as Example 1.

[0090] Comparative Example 2

[0091] The difference from Example 1 is that the co-extruded film does not contain a long afterglow layer; otherwise, it is the same as Example 1.

[0092] Comparative Example 3

[0093] The difference from Example 1 is that the co-extruded film does not contain a white filler layer; otherwise, it is the same as Example 1.

[0094] The films prepared in Examples 1 to 15 and Comparative Examples 1 to 3 were tested using the following methods:

[0095] Performance testing:

[0096] Transmittance of light diffusion layer: The test method is specified in GB / T 29848-2013, wavelength range of 380~1100nm.

[0097] Power of 16-cell solar module: Test method is as per IEC 61215.

[0098] Reflectance: The reflectance at wavelengths of 400–1100 nm was measured using a UV-Vis spectrophotometer.

[0099] The test results are shown in Table 1.

[0100] Table 1

[0101] Example Light transmittance, % Reflectivity, % Power, W 1 91.2 91.5 74.2 2 90.8 91.3 72.5 3 91.4 91.2 72.3 4 90.9 91.4 73.5 5 90.7 91.1 71.3 6 90.9 91.4 73.7 7 91.1 91.3 73.8 8 91.0 91.1 72.4 9 90.7 91 71.2 10 90.9 91.3 72.3 11 90.8 91.2 72.4 12 91.1 91.5 73.1 13 90.7 91 71.8 14 90.5 90.8 71.1 15 90.6 90.9 71.3 Comparative Example 1 90.1 89.9 70.0 2 89.7 90 69.8 3 89.9 89.8 70.1

[0102] As can be seen from the above description, the transmittance, reflectance, and power of the film prepared in the embodiments are higher than those of the film prepared in the comparative example. Although the absolute increase is not large, the above-mentioned increase is already considered a relatively significant performance improvement in the industry. Specifically, the above-mentioned embodiments of the present invention achieve the following technical effects:

[0103] Comparing Examples 1 to 15 and Comparative Examples 1 to 3, it can be seen that the film prepared by the method provided in this application has better photoelectric conversion performance.

[0104] Comparing Examples 1 to 5, it can be seen that limiting the amount of each component in the light diffusion layer within the preferred range is beneficial to improving the photoelectric conversion performance of the film.

[0105] Comparing Examples 1, 6 to 9, it can be seen that limiting the amount of each component in the long afterglow layer within the preferred range is beneficial to improving the photoelectric conversion performance of the film.

[0106] Comparing Examples 1, 10 to 13, it can be seen that limiting the amount of each component in the white filler layer within the preferred range is beneficial to improving the photoelectric conversion performance of the film.

[0107] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those described herein.

[0108] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing an adhesive film, characterized in that, The preparation method includes: The first matrix resin, the first initiator, and the light diffusing agent are mixed to obtain the light diffusing layer formulation; The second matrix resin, the second initiator, and the long afterglow material are mixed to obtain the long afterglow layer formulation; The third matrix resin, the third initiator, and the white filler are mixed to obtain the white filler layer formulation; The light diffusion layer, the long afterglow layer, and the white filler layer are melt-co-extruded to obtain the adhesive film. The thickness ratio of the light diffusion layer, the long afterglow layer, and the white filler layer is 1:(0.2-5):(0.4-10). The long afterglow material is an alkaline earth aluminate; The white filler layer also includes a superdispersant; the superdispersant is a hydroxyl-terminated aliphatic hyperbranched polyester.

2. The preparation method according to claim 1, characterized in that, The light diffusion layer formulation also includes: a first crosslinking agent and a first thickener.

3. The preparation method according to claim 2, characterized in that, By weight, the light diffusion layer comprises 100 parts of the first matrix resin, 0.05 to 1.5 parts of the first initiator, 0.5 to 3 parts of the first crosslinking agent, 0.1 to 5 parts of the first tackifier, and 0.1 to 5 parts of the light diffusion agent.

4. The preparation method according to claim 2, characterized in that, The light diffusing agent is an organosilicon resin with a particle size of 1–10 μm.

5. The preparation method according to claim 4, characterized in that, The light diffusing agent is a vinyl silane and / or an aromatic silane.

6. The preparation method according to any one of claims 2 to 5, characterized in that, The long afterglow layer formulation also includes a second crosslinking agent and a second thickener.

7. According to the preparation method of claim 6, the long afterglow layer comprises, by weight, 100 parts of the second matrix resin, 0.05 to 1.5 parts of the second initiator, 0.5 to 3 parts of the second crosslinking agent, 0.1 to 5 parts of the second tackifier, and 0.5 to 5 parts of the long afterglow material.

8. The preparation method according to claim 6, characterized in that, The long afterglow material is SrAl2O4:Eu, Sr4Al 14 O 25 Eu or CaAl2O4:Eu, with a particle size of 5–100 nm.

9. The preparation method according to claim 6, characterized in that, The white filler layer formulation also includes a third crosslinking agent and a third thickener.

10. The preparation method according to claim 9, characterized in that, By weight, the white filler layer comprises 100 parts of the third matrix resin, 0.05 to 1.5 parts of the third initiator, 0.5 to 3 parts of the third crosslinking agent, 0.1 to 5 parts of the third tackifier, 0.5 to 10 parts of the white filler, and 0.1 to 1 part of the superdispersant.

11. The preparation method according to claim 9, characterized in that, The white filler is selected from one or more of the group consisting of titanium dioxide, barium sulfate, calcium carbonate, mica, and talc.

12. The preparation method according to any one of claims 9 to 11, characterized in that, The first matrix resin, the second matrix resin, and the third matrix resin are each independently selected from one or more of the group consisting of polyolefin elastomers, ethylene-vinyl acetate copolymers, or polyvinyl butyral. The first initiator, the second initiator, and the third initiator are each independently selected from free radical thermal initiators; The first co-crosslinking agent, the second co-crosslinking agent, and the third co-crosslinking agent are multifunctional acrylates, and the number of functional groups is ≥2; The first tackifying resin, the second tackifying resin, and the third tackifying resin are each independently selected from silane coupling agents.

13. The preparation method according to claim 12, characterized in that, The first initiator, the second initiator, and the third initiator are each independently selected from one or more of the following groups: tert-butyl peroxycarbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-butyl peroxycarbonate-2-ethylhexyl ester, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,1-bis(tert-pentylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-pentylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-pentyl peroxycarbonate, and tert-pentyl peroxycarbonate.

14. The preparation method according to claim 12, characterized in that, The first, second, and third co-crosslinking agents are each independently selected from one or more of the following groups: tri(2-hydroxyethyl)isocyanurate triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, trimethylolpropane trimethacrylate, 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, tricyclodecanediethanol diacrylate, propoxylated neopentyl glycol diacrylate, and ethoxylated bisphenol A diacrylate.

15. The preparation method according to claim 12, characterized in that, The first tackifying resin, the second tackifying resin, and the third tackifying resin are each independently selected from one or more of the group consisting of γ-aminopropyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, vinyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

16. A film, characterized in that, The adhesive film is prepared by any one of claims 1 to 15.

17. A photovoltaic module, comprising an encapsulating film, characterized in that, The encapsulating film includes the film according to claim 16.

Images