A heterojunction battery adhesive film and preparation method thereof

Abstract

The invention discloses a heterojunction battery adhesive film and a preparation method thereof, and relates to the technical field of heterojunction batteries. The adhesive film is made of the following raw materials by weight: 100 parts of POE resin, 2-5 parts of a cross-linking agent, 10-20 parts of poly (4-methyl-1-pentene), 25-35 parts of a functional copolymer, 3-5 parts of 1,3,5-triacryloyl-s-triazine, 1-3 parts of tetramethyltetravinylcyclotetrasiloxane, 0.3-0.6 parts of an antioxidant, and 0.5-1.2 parts of a silane coupling agent; the functional copolymer includes a structural unit introduced by free radical polymerization of the following monomers: hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, and N-(4-cyano-3-trifluoromethylphenyl)methacrylamide. The adhesive film has good bonding performance, good resistance to wet and hot aging and yellowing resistance, and a long service life.

Description

Technical Field

[0001] The present invention relates to the technical field of heterojunction batteries, and in particular to a heterojunction battery adhesive film and a preparation method thereof. Background Art

[0002] Heterojunction solar cells, whose full name is crystalline silicon heterojunction solar cells, are a new type of solar cell technology that combines the advantages of crystalline silicon cells and thin-film cells. By depositing amorphous silicon thin films on crystalline silicon, it achieves the characteristics of high potential for improving photoelectric conversion efficiency, greater cost reduction space, higher bifaciality, effective reduction of heat loss, lower light-induced attenuation, and simple preparation process. As an important component of heterojunction solar cells, the encapsulation film is mainly used to protect solar cells and tightly bond the cells to glass, backplane and other materials into a whole. The performance of heterojunction cell film directly affects the photoelectric conversion efficiency and cycle life of heterojunction cells. It can be seen that it is particularly important to develop heterojunction cell films with excellent comprehensive performance and performance stability.

[0003] Existing heterojunction battery adhesive films have more or less technical defects such as poor adhesion to HJT battery cells, insufficient resistance to moisture and heat aging, high fluidity of the adhesive film leading to wire slippage, and the packaging effect and yellowing resistance need to be further improved. For example, the Chinese invention patent with the authorization announcement number CN115851147B discloses a low-fluidity packaging adhesive film for heterojunction battery components and its preparation method. The raw materials for preparing the packaging adhesive film include 40-80 parts of base resin, 20-60 parts of functional resin, 0.01-0.6 parts of main cross-linking agent, 0.2-0.8 parts of auxiliary cross-linking agent, 0.01-1 parts of anti-aging agent, and 0-1 parts of silane coupling agent by weight; the functional resin is a POE grafting material. The adhesive film prepared by the invention has low fluidity and maintains a sufficiently low modulus to effectively reduce the hidden cracks generated in the battery lamination. It also has good and lasting adhesion to heterojunction battery cells and is suitable for the packaging of heterojunction components. However, its resistance to wet and hot aging and yellowing still needs to be further improved.

[0004] Therefore, the development of a heterojunction battery adhesive film with good bonding properties, good resistance to moisture and heat aging and yellowing resistance, and long service life and a preparation method thereof meet market demand, have broad market value and application prospects, and are of great significance to promoting the development of heterojunction solar cell packaging technology. Summary of the invention

[0005] The main purpose of the present invention is to provide a heterojunction battery adhesive film with good bonding performance, good resistance to moisture and heat aging and yellowing, and long service life, and a preparation method thereof.

[0006] To achieve the above purpose, the present invention provides a heterojunction battery adhesive film, which is made of the following raw materials in parts by weight: 100 parts of POE resin, 2-5 parts of a cross-linking agent, 10-20 parts of poly(4-methyl-1-pentene), 25-35 parts of a functional copolymer, 3-5 parts of 1,3,5-triacryloyl-s-triazine, 1-3 parts of tetramethyltetravinylcyclotetrasiloxane, 0.3-0.6 parts of an antioxidant, and 0.5-1.2 parts of a silane coupling agent; the functional copolymer includes structural units introduced by free radical polymerization of the following monomers: hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, and N-(4-cyano-3-trifluoromethylphenyl)methacrylamide.

[0007] Preferably, the silane coupling agent is at least one of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570.

[0008] Preferably, the antioxidant is at least one of antioxidant 1010, antioxidant 1076, and antioxidant 168.

[0009] Preferably, the preparation method of the functional copolymer comprises the following steps: adding hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, N-(4-cyano-3-trifluoromethylphenyl)methacrylamide and an initiator to a high boiling point solvent, stirring and reacting at 60-70°C for 3-6 hours in an inert gas atmosphere, precipitating in water after the reaction, washing the precipitated polymer with ethanol for 3-6 times, and finally drying in a vacuum drying oven at 85-95°C to constant weight to obtain a functional copolymer.

[0010] Preferably, the mass ratio of hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, N-(4-cyano-3-trifluoromethylphenyl)methacrylamide, initiator, and high boiling point solvent is (1-2):1:(0.8-1.2):1.5:(0.03-0.05):(10-20).

[0011] Preferably, the initiator is azobisisobutyronitrile; and the high boiling point solvent is at least one of dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone.

[0012] Preferably, the inert gas is any one of nitrogen, helium, neon and argon.

[0013] Preferably, the poly(4-methyl-1-pentene) is selected from TPX™ MX004.

[0014] Preferably, the cross-linking agent is a mixture of dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, bis(tert-butylperoxyisopropyl)benzene, and benzoyl peroxide in a mass ratio of 2:(0.8-1.2):1:(1-2).

[0015] Preferably, the POE resin is POE resin with a brand number of 7467 provided by Dow Chemical.

[0016] Another object of the present invention is to provide a method for preparing the heterojunction battery film, comprising the following steps: adding the raw materials by weight into a stirring kettle, stirring evenly, putting the mixed materials into a screw extruder, melting and plasticizing, and then casting a smooth and uniform heterojunction battery film through a die lip.

[0017] Preferably, the thickness of the heterojunction battery film is 0.1 mm to 1 mm.

[0018] Due to the application of the above technical solution, the present invention has the following beneficial effects:

[0019] (1) The method for preparing the heterojunction battery adhesive film disclosed in the present invention can be realized by using conventional equipment and operating processes, is simple and easy to implement, requires little capital investment, has low energy consumption, has high preparation efficiency and finished product qualification rate, has low labor intensity, has little impact on the environment, is suitable for continuous large-scale production, and has high promotion and application value.

[0020] (2) The heterojunction battery adhesive film disclosed in the present invention is made of the following raw materials in parts by weight: 100 parts of POE resin, 2-5 parts of cross-linking agent, 10-20 parts of poly (4-methyl-1-pentene), 25-35 parts of functional copolymer, 3-5 parts of 1,3,5-triacryloyl-isotriazine, 1-3 parts of tetramethyltetravinylcyclotetrasiloxane, 0.3-0.6 parts of antioxidant, and 0.5-1.2 parts of silane coupling agent; through the mutual cooperation and joint action of the raw materials, the heterojunction battery adhesive film has good bonding performance, good resistance to moisture and heat aging and yellowing resistance, and long service life.

[0021] (3) The heterojunction battery adhesive film disclosed in the present invention, the functional copolymer includes the following structural units introduced by free radical polymerization: hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, N-(4-cyano-3-trifluoromethylphenyl)methacrylamide. The hydroxyethyl methacrylate, acylmorpholine, pyrrolo[3,2-B]pyridine, cyano, trifluoromethylphenyl and amide groups introduced at the same time cooperate with the triazine group and polyolefin group introduced by other raw materials under the multiple effects of electronic effect, steric effect and conjugation effect, so that the adhesive film has better bonding performance, better resistance to wet heat aging and yellowing resistance, and longer service life. DETAILED DESCRIPTION

[0022] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations. Example 1

[0023] A heterojunction battery adhesive film is made of the following raw materials in parts by weight: 100 parts of POE resin, 2 parts of a cross-linking agent, 10 parts of poly(4-methyl-1-pentene), 25 parts of a functional copolymer, 3 parts of 1,3,5-triacryloyl-s-triazine, 1 part of tetramethyltetravinylcyclotetrasiloxane, 0.3 parts of an antioxidant, and 0.5 parts of a silane coupling agent; the functional copolymer includes structural units introduced by free radical polymerization of the following monomers: hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, and N-(4-cyano-3-trifluoromethylphenyl)methacrylamide.

[0024] The silane coupling agent is silane coupling agent KH550; the antioxidant is antioxidant 1010.

[0025] The preparation method of the functional copolymer comprises the following steps: adding hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, N-(4-cyano-3-trifluoromethylphenyl)methacrylamide and an initiator to a high boiling point solvent, stirring and reacting for 3 hours at 60°C in an inert gas atmosphere, precipitating in water after the reaction, washing the precipitated polymer with ethanol for 3 times, and finally drying in a vacuum drying oven at 85°C to constant weight to obtain the functional copolymer; the mass ratio of the hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, N-(4-cyano-3-trifluoromethylphenyl)methacrylamide, initiator and high boiling point solvent is 1:1:0.8:1.5:0.03:10; the initiator is azobisisobutyronitrile; the high boiling point solvent is dimethyl sulfoxide; and the inert gas is nitrogen. Through GPC test, the Mn of the functional polymer was measured to be 15710 g / mol, M W / M n =1.337; through elemental analysis, infrared analysis and weight change calculation, the mass ratio of the structural units introduced by hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine and N-(4-cyano-3-trifluoromethylphenyl)methacrylamide in the functional copolymer is 0.98:1:0.79:1.47.

[0026] The poly(4-methyl-1-pentene) is selected from TPX™ MX004; the cross-linking agent is a mixture of diisopropyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, bis(tert-butylperoxyisopropyl)benzene, and benzoyl peroxide in a mass ratio of 2:0.8:1:1; and the POE resin is a POE resin with a grade of 7467 provided by Dow Chemical.

[0027] A method for preparing the heterojunction battery film comprises the following steps: adding raw materials by weight into a stirring kettle, stirring evenly, putting the mixed materials into a screw extruder, melting and plasticizing, and then casting a flat and uniform heterojunction battery film through a die lip; the thickness of the heterojunction battery film is 0.5 mm. Example 2

[0028] A heterojunction battery adhesive film is made of the following raw materials in parts by weight: 100 parts of POE resin, 3.5 parts of a cross-linking agent, 15 parts of poly(4-methyl-1-pentene), 30 parts of a functional copolymer, 4 parts of 1,3,5-triacryloyl-s-triazine, 2 parts of tetramethyltetravinylcyclotetrasiloxane, 0.45 parts of an antioxidant, and 0.9 parts of a silane coupling agent; the functional copolymer includes structural units introduced by free radical polymerization of the following monomers: hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, and N-(4-cyano-3-trifluoromethylphenyl)methacrylamide.

[0029] The silane coupling agent is silane coupling agent KH560; the antioxidant is antioxidant 1076.

[0030] The preparation method of the functional copolymer comprises the following steps: adding hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, N-(4-cyano-3-trifluoromethylphenyl)methacrylamide and an initiator into a high boiling point solvent, stirring and reacting at 63°C for 4 hours in an inert gas atmosphere, precipitating the polymer in water after the reaction is completed, washing the precipitated polymer with ethanol for 4 times, and finally drying the polymer in a vacuum drying oven at 87°C. to constant weight to obtain a functional copolymer; the mass ratio of hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, N-(4-cyano-3-trifluoromethylphenyl)methacrylamide, initiator, and high boiling point solvent is 1.2:1:0.9:1.5:0.035:13; the initiator is azobisisobutyronitrile; the high boiling point solvent is N,N-dimethylformamide; and the inert gas is helium.

[0031] The poly(4-methyl-1-pentene) is selected from TPX™ MX004; the cross-linking agent is a mixture of diisopropyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, bis(tert-butylperoxyisopropyl)benzene, and benzoyl peroxide in a mass ratio of 2:0.9:1:1.2; and the POE resin is a POE resin with a grade of 7467 provided by Dow Chemical.

[0032] A method for preparing the heterojunction battery film comprises the following steps: adding raw materials by weight into a stirring kettle, stirring evenly, putting the mixed materials into a screw extruder, melting and plasticizing, and then casting a flat and uniform heterojunction battery film through a die lip; the thickness of the heterojunction battery film is 0.5 mm. Example 3

[0033] A heterojunction battery adhesive film is made of the following raw materials in parts by weight: 100 parts of POE resin, 3.5 parts of a cross-linking agent, 15 parts of poly(4-methyl-1-pentene), 30 parts of a functional copolymer, 4 parts of 1,3,5-triacryloyl-s-triazine, 2 parts of tetramethyltetravinylcyclotetrasiloxane, 0.45 parts of an antioxidant, and 0.9 parts of a silane coupling agent; the functional copolymer includes structural units introduced by free radical polymerization of the following monomers: hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, and N-(4-cyano-3-trifluoromethylphenyl)methacrylamide.

[0034] The silane coupling agent is silane coupling agent KH570; the antioxidant is antioxidant 168.

[0035] The preparation method of the functional copolymer comprises the following steps: adding hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, N-(4-cyano-3-trifluoromethylphenyl)methacrylamide and an initiator into a high boiling point solvent, stirring and reacting at 65°C for 4.5 hours in an inert gas atmosphere, precipitating the polymer in water after the reaction is completed, washing the precipitated polymer with ethanol for 5 times, and finally placing the polymer in a vacuum drying oven at 90 ℃ and dried to constant weight to obtain a functional copolymer; the mass ratio of hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, N-(4-cyano-3-trifluoromethylphenyl)methacrylamide, initiator, and high boiling point solvent is 1.5:1:1:1.5:0.04:15; the initiator is azobisisobutyronitrile; the high boiling point solvent is N-methylpyrrolidone; and the inert gas is neon.

[0036] The poly(4-methyl-1-pentene) is selected from TPX™ MX004; the cross-linking agent is a mixture of diisopropyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, bis(tert-butylperoxyisopropyl)benzene, and benzoyl peroxide in a mass ratio of 2:1:1:1.5; and the POE resin is a POE resin with a grade of 7467 provided by Dow Chemical.

[0037] A method for preparing the heterojunction battery film comprises the following steps: adding raw materials by weight into a stirring kettle, stirring evenly, putting the mixed materials into a screw extruder, melting and plasticizing, and then casting a flat and uniform heterojunction battery film through a die lip; the thickness of the heterojunction battery film is 0.5 mm. Example 4

[0038] A heterojunction battery adhesive film is made of the following raw materials in parts by weight: 100 parts of POE resin, 4.5 parts of a cross-linking agent, 18 parts of poly(4-methyl-1-pentene), 33 parts of a functional copolymer, 4.5 parts of 1,3,5-triacryloyl-s-triazine, 2.5 parts of tetramethyltetravinylcyclotetrasiloxane, 0.55 parts of an antioxidant, and 1 part of a silane coupling agent; the functional copolymer includes structural units introduced by free radical polymerization of the following monomers: hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, and N-(4-cyano-3-trifluoromethylphenyl)methacrylamide.

[0039] The silane coupling agent is a mixture of silane coupling agent KH550, silane coupling agent KH560 and silane coupling agent KH570 in a mass ratio of 1:2:3; the antioxidant is a mixture of antioxidant 1010, antioxidant 1076 and antioxidant 168 in a mass ratio of 1:1:3.

[0040] The preparation method of the functional copolymer comprises the following steps: adding hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, N-(4-cyano-3-trifluoromethylphenyl)methacrylamide and an initiator to a high boiling point solvent, stirring and reacting at 68°C in an inert gas atmosphere for 5.5 hours, precipitating the polymer in water after the reaction is completed, washing the precipitated polymer with ethanol for 6 times, and finally drying the polymer in a vacuum drying oven at 93°C to a constant weight to obtain the functional copolymer; The mass ratio of hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, N-(4-cyano-3-trifluoromethylphenyl)methacrylamide, initiator and high boiling point solvent is 1.8:1:1.1:1.5:0.045:18; the initiator is azobisisobutyronitrile; the high boiling point solvent is a mixture of dimethyl sulfoxide, N,N-dimethylformamide and N-methylpyrrolidone in a mass ratio of 1:1:1; the inert gas is argon.

[0041] The poly(4-methyl-1-pentene) is selected from TPX™ MX004; the cross-linking agent is a mixture of diisopropyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, bis(tert-butylperoxyisopropyl)benzene, and benzoyl peroxide in a mass ratio of 2:1.1:1:1.8; and the POE resin is a POE resin with a grade of 7467 provided by Dow Chemical.

[0042] A method for preparing the heterojunction battery film comprises the following steps: adding raw materials by weight into a stirring kettle, stirring evenly, putting the mixed materials into a screw extruder, melting and plasticizing, and then casting a flat and uniform heterojunction battery film through a die lip; the thickness of the heterojunction battery film is 0.5 mm. Example 5

[0043] A heterojunction battery adhesive film is made of the following raw materials in parts by weight: 100 parts of POE resin, 5 parts of a cross-linking agent, 20 parts of poly(4-methyl-1-pentene), 35 parts of a functional copolymer, 5 parts of 1,3,5-triacryloyl-s-triazine, 3 parts of tetramethyltetravinylcyclotetrasiloxane, 0.6 parts of an antioxidant, and 1.2 parts of a silane coupling agent; the functional copolymer includes structural units introduced by free radical polymerization of the following monomers: hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, and N-(4-cyano-3-trifluoromethylphenyl)methacrylamide.

[0044] The silane coupling agent is silane coupling agent KH550; the antioxidant is antioxidant 1076.

[0045] The preparation method of the functional copolymer comprises the following steps: adding hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, N-(4-cyano-3-trifluoromethylphenyl)methacrylamide and an initiator to a high boiling point solvent, stirring and reacting for 6 hours at 70°C in an inert gas atmosphere, precipitating in water after the reaction, washing the precipitated polymer with ethanol for 6 times, and finally drying in a vacuum drying oven at 95°C to constant weight to obtain the functional copolymer; the mass ratio of the hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, N-(4-cyano-3-trifluoromethylphenyl)methacrylamide, initiator and high boiling point solvent is 2:1:1.2:1.5:0.05:20; the initiator is azobisisobutyronitrile; the high boiling point solvent is dimethyl sulfoxide; and the inert gas is nitrogen.

[0046] The poly(4-methyl-1-pentene) is selected from TPX™ MX004; the cross-linking agent is a mixture of diisopropyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, bis(tert-butylperoxyisopropyl)benzene, and benzoyl peroxide in a mass ratio of 2:1.2:1:2; and the POE resin is a POE resin with a grade of 7467 provided by Dow Chemical.

[0047] A method for preparing the heterojunction battery film comprises the following steps: adding raw materials by weight into a stirring kettle, stirring evenly, putting the mixed materials into a screw extruder, melting and plasticizing, and then casting a flat and uniform heterojunction battery film through a die lip; the thickness of the heterojunction battery film is 0.5 mm.

[0048] Comparative Example 1

[0049] A heterojunction battery adhesive film and a preparation method thereof, which are similar to Example 1, except that POE resin is used instead of poly(4-methyl-1-pentene) and 1,3,5-triacryloyl-s-triazine is not added.

[0050] Comparative Example 2

[0051] A heterojunction battery adhesive film and a preparation method thereof, which are similar to Example 1, except that POE resin is used instead of the functional copolymer, and tetramethyltetravinylcyclotetrasiloxane is not added.

[0052] In order to further illustrate the beneficial technical effects of the heterojunction battery adhesive film involved in each embodiment of the present invention, the heterojunction battery adhesive film involved in Examples 1-5 and Comparative Examples 1-2 was subjected to relevant performance tests, and the test results are shown in Table 1. The test method is as follows: The test method refers to NB / T 10200-2019. Among them, the PCT aging performance (PCT 24h) is measured by the yellowing index before and after aging, and the larger the value, the worse the PCT aging resistance; the wet heat aging performance (2000h) is measured by the yellowing index before and after aging, and the larger the value, the worse the wet heat aging resistance.

[0053] Table 1

[0054] Test items Peel strength with glass Peel strength with back sheet PCT aging performance (PCT24h) Humidity and heat aging performance (2000h) unit N / cm N / cm — — Example 1 135 120 0.87 0.65 Example 2 139 122 0.80 0.61 Example 3 141 125 0.69 0.54 Example 4 146 126 0.61 0.49 Example 5 149 130 0.55 0.46 Comparative Example 1 120 109 1.35 1.47 Comparative Example 2 114 103 2.06 1.89

[0055] It can be seen from Table 1 that the heterojunction battery adhesive films involved in the embodiments of the present invention have better peel strength, PCT aging resistance and wet heat aging resistance. The combined use of POE resin, poly (4-methyl-1-pentene), functional copolymer, 1,3,5-triacryloyl triazine and tetramethyltetravinylcyclotetrasiloxane is beneficial to improving the above properties.

[0056] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A heterojunction battery adhesive film, characterized in that: The invention is prepared from the following raw materials in parts by weight: 100 parts of POE resin, 2-5 parts of crosslinking agent, 10-20 parts of poly(4-methyl-1-pentene), 25-35 parts of functional copolymer, 3-5 parts of 1,3,5-triacryloyl-s-triazine, 1-3 parts of tetramethyltetravinylcyclotetrasiloxane, 0.3-0.6 parts of antioxidant, and 0.5-1.2 parts of silane coupling agent; the functional copolymer includes structural units introduced by free radical polymerization of the following monomers: hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, and N-(4-cyano-3-trifluoromethylphenyl)methacrylamide; The preparation method of the functional copolymer comprises the following steps: adding hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, N-(4-cyano-3-trifluoromethylphenyl)methacrylamide and an initiator to a high boiling point solvent, stirring and reacting for 3-6 hours at 60-70°C in an inert gas atmosphere, precipitating the polymer in water after the reaction is completed, washing the precipitated polymer with ethanol for 3-6 times, and finally drying the polymer in a vacuum drying oven at 85-95°C to a constant weight to obtain the functional copolymer; the mass ratio of the hydroxyethyl methacrylate, N-acryloylmorpholine, 5-methoxy-2-vinyl-1H-pyrrolo[3,2-B]pyridine, N-(4-cyano-3-trifluoromethylphenyl)methacrylamide, the initiator and the high boiling point solvent is (1-2):1:(0.8-1.2):1.5:(0.03-0.05):(10-20).

2. The heterojunction battery adhesive film according to claim 1, characterized in that: The silane coupling agent is at least one of silane coupling agent KH550, silane coupling agent KH560 and silane coupling agent KH570.

3. The heterojunction battery adhesive film according to claim 1, characterized in that: The antioxidant is at least one of antioxidant 1010 , antioxidant 1076 , and antioxidant 168 .

4. The heterojunction battery adhesive film according to claim 1, characterized in that: The initiator is azobisisobutyronitrile; the high boiling point solvent is at least one of dimethyl sulfoxide, N,N-dimethylformamide and N-methylpyrrolidone.

5. The heterojunction battery adhesive film according to claim 1, characterized in that: The inert gas is any one of nitrogen, helium, neon and argon.

6. The heterojunction battery adhesive film according to claim 1, characterized in that: The poly(4-methyl-1-pentene) is selected from TPX™ MX004; and the POE resin is a POE resin with a brand number of 7467 provided by Dow Chemical.

7. The heterojunction battery adhesive film according to claim 1, characterized in that: The crosslinking agent is a mixture of dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, di(tert-butylperoxyisopropyl)benzene and benzoyl peroxide in a mass ratio of 2:(0.8-1.2):1:(1-2).

8. A method for preparing a heterojunction battery adhesive film according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: adding raw materials by weight into a stirring kettle, stirring evenly, feeding the mixed materials into a screw extruder, melting and plasticizing, and then casting a flat and uniform heterojunction battery film through a die lip; the thickness of the heterojunction battery film is 0.1 mm to 1 mm.