High-permeability deacidification anti-PID type EVA packaging adhesive film and preparation method thereof

Abstract

The invention belongs to the technical field of photovoltaic packaging adhesive films, and particularly relates to a high-permeability deacidification anti-PID type EVA packaging adhesive film and a preparation method thereof, and the preparation method comprises the following steps: S1, mixing materials; s2, extruding; s3, forming a film; wherein the raw materials in the step S1 comprise a deacidification agent, and a preparation method of the deacidification agent comprises the following steps: S11, dissolving urea and hexadecyl trimethyl ammonium bromide in deionized water, and stirring to form a first solution; mixing amyl alcohol and cyclohexane, adding tetraethyl orthosilicate, stirring, and adding an aperture regulator into the mixed solution to form a second solution; s12, mixing the first solution and the second solution, stirring, adding into a reaction kettle with a polytetrafluoroethylene lining, and centrifugally separating to obtain an intermediate product; s13, calcining the intermediate product to obtain a mesoporous silica material; and S14, putting the mesoporous silica into a toluene solution, dropwise adding an amino silane coupling agent, condensing and refluxing, and centrifugally separating to obtain the deacidification agent.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic encapsulation films, and in particular relates to a high-transmittance, acid-removing, and PID-resistant EVA encapsulation film and a preparation method thereof. Background Art

[0002] EVA (ethylene-vinyl acetate copolymer) film is a thermosetting adhesive widely used in the encapsulation of solar cell modules. Its primary function is to bond the photovoltaic glass, cells, and backsheet together, protecting the cells and isolating them from air and moisture, thereby extending the life of the module. While EVA film accounts for approximately 3%-4% of the cost of a photovoltaic module, its performance directly impacts module quality and power generation efficiency.

[0003] However, EVA film faces many challenges in long-term outdoor use. Due to long-term exposure to ultraviolet radiation, infrared radiation, high temperature and high humidity, EVA film is prone to aging. When its molecular chain decomposes, it releases acetic acid, which corrodes the glass and backplane, and at the same time causes Na in the glass layer to degrade. + The migration of the components leads to potential induced degradation (PID), which in turn reduces the power generation capacity of the components.

[0004] Therefore, how to overcome the defect that EVA encapsulation film is prone to aging in a hot and humid environment is a technical problem that needs to be solved urgently in this field.

[0005] Therefore, how to overcome the agglomeration defect of inorganic fillers in acid-removing EVA encapsulation films is a technical problem that urgently needs to be solved in this field.

[0006] It should be noted that the above information disclosed in this background technology section is only used to understand the background technology of the present application concept, and therefore, the above description is not considered to constitute information of the prior art. Summary of the Invention

[0007] The embodiments of the present disclosure at least provide a highly transparent, acid-removing, and PID-resistant EVA encapsulation film and a preparation method thereof.

[0008] In the first aspect, the embodiment of the present disclosure provides a preparation method of an EVA encapsulating film, comprising the following steps: S1 mixing, putting the raw materials into a mixer for mixing and stirring to obtain a mixed raw material; S2 extrusion, pouring the mixed raw material into a single-screw extruder, and obtaining an extrudate through melt blending, discharging casting, and roller cooling; S3 film forming, measuring the thickness of the extrudate, pressing the edge, shaping, and then trimming and winding to obtain an EVA encapsulating film; wherein the raw materials in S1 include an acid scavenger, and the preparation method of the acid scavenger comprises the following steps: S11, dissolving urea and hexadecyltrimethylammonium bromide in deionized water, stirring to form a film; to form a first solution; after mixing pentanol and cyclohexane, add tetraethyl orthosilicate, stir and then add a pore size regulator to the mixture to form a second solution; S12, mix the first solution and the second solution, stir and then add them to a polytetrafluoroethylene-lined reactor, after stirring the reaction, wash with deionized water and acetone respectively, and centrifuge to obtain an intermediate product; S13, calcine the intermediate product to obtain a mesoporous silica material; S14, place the mesoporous silica in a toluene solution, add an aminosilane coupling agent dropwise, condense and reflux, after the reaction is completed, wash the precipitate with ethanol and water respectively, and centrifuge to obtain an acid scavenger.

[0009] In an optional embodiment, step S1 includes the following raw materials in parts by weight: 100 parts of EVA resin, 0.5-2.0 parts of cross-linking agent, 0.1-2.0 parts of auxiliary cross-linking agent, 0.1-0.5 parts of coupling agent, 0.1-5.0 parts of acid scavenger, 0.1-1.0 parts of light stabilizer, and 0.1-1.0 parts of antioxidant.

[0010] In an optional embodiment, in step S11, the mass ratio of urea, hexadecyltrimethylammonium bromide, and deionized water is 1:2:50.

[0011] In an optional embodiment, in step S11, the volume ratio of pentanol, cyclohexane, and tetraethyl orthosilicate is 2.5:50:5.

[0012] In an optional embodiment, the pore size regulator in step S11 is any one of 1,3,5-triisopropylbenzene, methylene blue, sodium trifluoroacetate and sodium perfluorooctanoate; and the mass ratio of the pore size regulator to the mixed solution is not higher than 20:57.5.

[0013] In an optional embodiment, the pore size range of the mesoporous silica material after calcination in step S13 is 1.0 to 7.5 nm.

[0014] In an optional embodiment, the aminosilane coupling agent in step S14 includes any one of 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and diethylenetriaminopropyltrimethoxysilane.

[0015] In an optional embodiment, the cross-linking agent includes any one of 2,5-dimethyl-2,5-bis(tert-butyl peroxide)hexane, 2,5-dimethyl-2,5-bis(benzoyl peroxy)hexane, tert-butyl peroxycarbonate-2-ethylhexyl ester, tert-butyl peroxyacetate, benzoyl peroxide, lauroyl peroxide, diisopropyl benzene peroxide, and 1,1-bis(tert-butyl peroxy)-3,3,5-trimethylcyclohexane.

[0016] In an optional embodiment, the auxiliary cross-linking agent includes a mixture of any two or more of trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, diallyl phthalate, pentaerythritol triacrylate, propoxylated neopentyl glycol diacrylate, and propoxylated pentaerythritol tetraacrylate.

[0017] In an optional embodiment, the coupling agent includes any one of γ-mercaptopropyltriethoxysilane, vinyltriethoxysilane, vinyltriisopropylsilane, γ-glycidyloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane.

[0018] In an optional embodiment, the light stabilizer includes any one of mono(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, 3,5-di-tert-butyl-4-hydroxy-benzoic acid hexadecyl ester, and poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinethanol) succinate.

[0019] In an optional embodiment, the antioxidant comprises a mixture of any two or more of hindered phenol antioxidants, aromatic amine antioxidants, phosphite antioxidants, thioether antioxidants and metal passivator antioxidants.

[0020] In a second aspect, the embodiments of the present disclosure further provide an EVA encapsulation film, which is prepared by the method described above, and the EVA encapsulation film meets the following conditions: (1) the free acid ratio of the EVA encapsulation film is lower than 3.5; (2) the thermal conductivity of the EVA encapsulation film is lower than 0.25 W / (m·K).

[0021] In a third aspect, an embodiment of the present disclosure further provides a photovoltaic module, comprising a glass layer, an EVA encapsulation film layer, a solar cell, and an EVA encapsulation film layer arranged in sequence; wherein the EVA encapsulation film layer adopts the EVA encapsulation film as described above.

[0022] The beneficial effect of the present invention is that the high-transparency, acid-removing and PID-resistant EVA encapsulating film and its preparation method use an aminosilane coupling agent to modify the surface of nano-mesoporous silica, thereby changing its surface properties from hydrophilic to hydrophobic. At the same time, its porous structure has excellent free acid adsorption performance. In addition to being able to adsorb free acid and improve the dispersibility of the acid scavenger in the film, the aminosilane coupling agent can also make the acid scavenger have a larger specific surface area, thereby increasing the porosity, and can effectively block the heat transfer path in the polymer substrate, thereby giving the film a lower thermal conductivity coefficient, improving the thermal insulation performance, and ultimately achieving the aging resistance and PID resistance of the EVA encapsulating film in a hot and humid environment.

[0023] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description and the drawings.

[0024] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 This is an EL graph of the encapsulated EVA film and the battery cell after PCT aging according to Example 1 of the present disclosure;

[0027] Figure 2 This is an EL graph of the encapsulated EVA film and the battery cell after PCT aging according to Example 2 provided in the embodiments of the present disclosure;

[0028] Figure 3 This is an EL graph of the encapsulated EVA film and the battery cell after PCT aging according to Example 3 provided in the embodiments of the present disclosure;

[0029] Figure 4This is an EL graph of the encapsulated EVA film and the battery cell after PCT aging according to Comparative Example 1 provided in the embodiments of the present disclosure;

[0030] Figure 5 This is an EL graph of the encapsulated EVA film and the battery cell after PCT aging according to Comparative Example 2 provided in the embodiments of the present disclosure;

[0031] Figure 6 This is an EL diagram of the encapsulated EVA film and the battery cell after PCT aging in Comparative Example 3 provided in the embodiments of the present disclosure. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0033] As used herein, the phrases "in one embodiment," "according to one embodiment," "in some embodiments," and the like generally refer to the fact that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Thus, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms "example," "exemplary," and the like are used to "serve as an example, instance, or illustration." Any implementation, aspect, or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations, aspects, or designs. Instead, the use of the terms "example," "exemplary," and the like is intended to present concepts in a concrete manner.

[0034] Herein, example embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as "at least one of..." when following a list of elements modify the entire list of elements, rather than modifying individual elements in the list. For example, the expression "at least one of a, b, and c" should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0035] The terms used herein are only used to describe specific exemplary configurations and are not intended to be limiting. As used herein, the singular articles "a", "an" and "the" may also be intended to include plural forms, unless otherwise clearly indicated herein. The terms "comprise", "include" and "have" are inclusive and therefore specify the presence of features, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components and / or combinations thereof. The method steps, processes and operations described herein should not be interpreted as necessarily requiring them to be performed in the particular order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.

[0036] Due to the repulsive force between inorganic nanoparticles and organic polymers at the interface, the compatibility between polymers and nanoparticles is poor. This requires chemical modification and treatment of the filler particle surface to reduce the surface energy and, in turn, the surface charge of the particles, thereby effectively preventing interparticle aggregation. This further reduces the viscosity of the entire composite system, ultimately improving and enhancing the fluidity of the system. Ultimately, the compatibility between the particles and the polymer matrix is strengthened, promoting uniform dispersion of the filler particles within the polymer matrix. This requires the use of a silane coupling agent to couple the two dissimilar materials to form an inorganic phase-coupling agent-organic phase, achieving excellent compatibility between the matrix material and the filler, and further improving thermal stability, conductivity, and mechanical properties.

[0037] Currently, most existing technologies use the addition of inorganic fillers to neutralize free acetic acid. However, the fineness, shape, and surface structure of the inorganic fillers limit their dispersion in the polymer, or the acid removal effect is poor, resulting in a series of problems such as mechanical properties, light transmittance, and aging resistance.

[0038] Therefore, when the inventors improved the aging resistance of the EVA film, the dispersibility and compatibility of the inorganic filler that absorbs free acid must also be considered.

[0039] The defects in the above solutions are the results obtained by the inventors after practice and careful research. Therefore, the process of discovering the above problems and the solutions proposed by this disclosure for the above problems below should be the contributions made by the inventors to this disclosure during the disclosure process.

[0040] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not require further definition or explanation in subsequent drawings.

[0041] The following embodiments of the present invention are described in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features therein may be combined with each other.

[0042] The embodiment of the present disclosure provides a preparation method of an EVA encapsulating film, comprising the following steps: S1 mixing, putting the raw materials into a mixer for mixing and stirring to obtain a mixed raw material; S2 extrusion, pouring the mixed raw material into a single-screw extruder, and obtaining an extrudate through melt blending, discharging casting, and cooling on a roller; S3 film forming, measuring the thickness of the extrudate, pressing the edge, shaping, and then trimming and winding to obtain an EVA encapsulating film; wherein the raw materials in S1 include an acid scavenger, and the preparation method of the acid scavenger comprises the following steps: S11, dissolving urea and hexadecyltrimethylammonium bromide in deionized water, stirring to form a first solution; after mixing pentanol and cyclohexane, add tetraethyl orthosilicate, stir and then add pore size regulator to the mixture to form a second solution; S12, mix the first solution and the second solution, stir and add them into a polytetrafluoroethylene-lined reactor, after stirring the reaction, wash with deionized water and acetone respectively, and centrifuge to obtain an intermediate product; S13, calcine the intermediate product to obtain a mesoporous silica material; S14, place the mesoporous silica into a toluene solution, add aminosilane coupling agent dropwise, condense and reflux, after the reaction is completed, wash the precipitate with ethanol and water respectively, and centrifuge to obtain an acid scavenger.

[0043] In some embodiments, specifically, step S1 includes the following raw materials in parts by weight: 100 parts of EVA resin, 0.5-2.0 parts of cross-linking agent, 0.1-2.0 parts of auxiliary cross-linking agent, 0.1-0.5 parts of coupling agent, 0.1-5.0 parts of acid scavenger, 0.1-1.0 parts of light stabilizer, and 0.1-1.0 parts of antioxidant.

[0044] In some embodiments, specifically, the mass ratio of urea, hexadecyltrimethylammonium bromide, and deionized water in step S11 is 1:2:50.

[0045] In some embodiments, specifically, in step S11, the volume ratio of pentanol, cyclohexane, and tetraethyl orthosilicate is 2.5:50:5.

[0046] In some embodiments, specifically, the pore size regulator in step S11 is any one of 1,3,5-triisopropylbenzene, methylene blue, sodium trifluoroacetate and sodium perfluorooctanoate; and the mass ratio of the pore size regulator to the mixed solution is not higher than 20:57.5.

[0047] In some embodiments, specifically, the pore size range of the mesoporous silica material after calcination in step S13 is 1.0 to 7.5 nm.

[0048] In some embodiments, specifically, the aminosilane coupling agent in step S14 includes any one of 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and diethylenetriaminopropyltrimethoxysilane.

[0049] In some embodiments, specifically, the cross-linking agent includes any one of 2,5-dimethyl-2,5-bis(tert-butyl peroxide)hexane, 2,5-dimethyl-2,5-bis(benzoyl peroxy)hexane, tert-butyl peroxycarbonate-2-ethylhexyl ester, tert-butyl peroxyacetate, benzoyl peroxide, lauroyl peroxide, dicumyl peroxide, and 1,1-bis(tert-butyl peroxy)-3,3,5-trimethylcyclohexane.

[0050] In some embodiments, specifically, the auxiliary cross-linking agent includes a mixture of any two or more of trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, diallyl phthalate, pentaerythritol triacrylate, propoxylated neopentyl glycol diacrylate, and propoxylated pentaerythritol tetraacrylate.

[0051] In some embodiments, specifically, the coupling agent includes any one of γ-mercaptopropyltriethoxysilane, vinyltriethoxysilane, vinyltriisopropylsilane, γ-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane.

[0052] In some embodiments, specifically, the light stabilizer includes any one of mono(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, 3,5-di-tert-butyl-4-hydroxy-benzoic acid hexadecyl ester, and poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinethanol) succinate.

[0053] In some embodiments, specifically, the antioxidant includes a mixture of any two or more of hindered phenol antioxidants, aromatic amine antioxidants, phosphite antioxidants, thioether antioxidants, and metal passivator antioxidants.

[0054] The present disclosure also provides an EVA encapsulation film, which is prepared by the method described above, and the EVA encapsulation film meets the following conditions: (1) the free acid ratio of the EVA encapsulation film is lower than 3.5; (2) the thermal conductivity of the EVA encapsulation film is lower than 0.25 W / (m·K).

[0055] The embodiment of the present disclosure further provides a photovoltaic module, comprising a glass layer, an EVA encapsulation film layer, a solar cell, and an EVA encapsulation film layer arranged in sequence; wherein the EVA encapsulation film layer adopts the EVA encapsulation film described above.

[0056] Example 1

[0057] The anti-PID encapsulation EVA film provided in this embodiment includes the following raw materials in parts by weight:

[0058] 100 parts of EVA resin, 1 part of 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, 0.3 parts of trimethylolpropane trimethacrylate, 0.3 parts of pentaerythritol triacrylate, 0.4 parts of vinyltriethoxysilane, 3.0 parts of acid scavenger, 0.2 parts of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, 10100.05 parts of hindered phenol antioxidant, and 1680.1 parts of phosphite antioxidant.

[0059] The above mixture was evenly mixed and poured into the extruder for blending and extrusion. The extruder parameters were adjusted, and the temperature from the feed port to the die head was 80°C, 90°C, 95°C, 95°C, 95°C, 90°C, 90°C, the screw speed was 50rpm, the pulling speed was 0.7rpm, and the winding speed was 1.3rpm. After extrusion, cast film, cooling, slitting and winding processes, an EVA film for encapsulation of photovoltaic modules was prepared. The film had a thickness of 0.5mm and a weight of 400g.

[0060] Wherein the acid scavenger is prepared according to the following method:

[0061] Step S11: dissolving urea and cetyltrimethylammonium bromide in deionized water in a certain proportion, and stirring the mixture to form a first solution;

[0062] Specifically, the usage ratio of urea, hexadecyltrimethylammonium bromide, and solvent is 1 g:2 g:50 mL.

[0063] Step S12: Pentanol and cyclohexane are mixed uniformly in proportion, tetraethyl orthosilicate is added, and the mixture is stirred uniformly. Then, a pore size regulator is added to the mixture and the mixture is stirred uniformly to form a second solution;

[0064] Specifically, the ratio of pentanol, cyclohexane, and tetraethyl orthosilicate is 2.5 mL: 50 mL: 5 mL; further, the pore size regulator is preferably 1,3,5-triisopropylbenzene, and the amount is 2 g;

[0065] Step S13: mixing the first solution and the second solution, stirring them evenly, and then adding them to a polytetrafluoroethylene-lined reactor, heating and stirring to react; after the reaction is completed, washing the mixture with deionized water and acetone respectively, and centrifuging to obtain an intermediate product;

[0066] Specifically, the heating temperature is 200° C. and the reaction time is 12 h.

[0067] Step S14: calcining the intermediate product at a high temperature to remove the template to obtain a mesoporous silica material;

[0068] Specifically, the temperature is 600° C. and the calcination is 6 h.

[0069] Step S15: Add 2 g of mesoporous silica material and 200 ml of toluene solution to a three-necked flask and ultrasonically disperse for 10 minutes; then place the three-necked flask in an oil bath, heat to 120° C., add a silane coupling agent dropwise, and condense and reflux for 15 hours; after the reaction is completed, wash the precipitate with ethanol and water respectively, centrifuge and dry to obtain a modified mesoporous silica material, i.e., an acid scavenger.

[0070] Specifically, the aminosilane coupling agent is preferably diethylenetriaminopropyltrimethoxysilane (KH-892); the amount used is 2 g.

[0071] Example 2

[0072] The anti-PID encapsulation EVA film provided in this embodiment has the same raw material parts as in specific embodiment 1.

[0073] Wherein the acid scavenger is prepared according to the following method:

[0074] Step S11: dissolving urea and cetyltrimethylammonium bromide in deionized water in a certain proportion, and stirring the mixture to form a first solution;

[0075] Specifically, the usage ratio of urea, hexadecyltrimethylammonium bromide, and solvent is 1 g:2 g:50 mL.

[0076] Step S12: Pentanol and cyclohexane are mixed uniformly in proportion, tetraethyl orthosilicate is added, and the mixture is stirred uniformly. Then, a pore size regulator is added to the mixture and the mixture is stirred uniformly to form a second solution;

[0077] Specifically, the usage ratio of pentanol, cyclohexane, and tetraethyl orthosilicate is 2.5 mL: 50 mL: 5 mL; further, the pore size regulator is preferably 1,3,5-triisopropylbenzene, and the usage amount is 20 g;

[0078] Step S13: mixing the first solution and the second solution, stirring them evenly, and then adding them to a polytetrafluoroethylene-lined reactor, heating and stirring to react; after the reaction is completed, washing the mixture with deionized water and acetone respectively, and centrifuging to obtain an intermediate product;

[0079] Specifically, the heating temperature is 200° C. and the reaction time is 12 h.

[0080] Step S14: calcining the intermediate product at a high temperature to remove the template to obtain a mesoporous silica material;

[0081] Specifically, the temperature is 600° C. and the calcination is 6 h.

[0082] Step S15: Add 2 g of mesoporous silica material and 200 ml of toluene solution to a three-necked flask and ultrasonically disperse for 10 minutes; then place the three-necked flask in an oil bath, heat to 120° C., add a silane coupling agent dropwise, and condense and reflux for 15 hours; after the reaction is completed, wash the precipitate with ethanol and water respectively, centrifuge and dry to obtain a modified mesoporous silica material, i.e., an acid scavenger.

[0083] Specifically, the aminosilane coupling agent is preferably diethylenetriaminopropyltrimethoxysilane (KH-892); the amount used is 2 g.

[0084] Example 3

[0085] The anti-PID encapsulation EVA film provided in this embodiment has the same raw material parts as in specific embodiment 1.

[0086] Wherein the acid scavenger is prepared according to the following method:

[0087] Step S11: dissolving urea and cetyltrimethylammonium bromide in deionized water in a certain proportion, and stirring the mixture to form a first solution;

[0088] Specifically, the usage ratio of urea, hexadecyltrimethylammonium bromide, and solvent is 1 g:2 g:50 mL.

[0089] Step S12: Pentanol and cyclohexane are mixed uniformly in proportion, tetraethyl orthosilicate is added, and the mixture is stirred uniformly. Then, a pore size regulator is added to the mixture and the mixture is stirred uniformly to form a second solution;

[0090] Specifically, the usage ratio of pentanol, cyclohexane, and tetraethyl orthosilicate is 2.5 mL: 50 mL: 5 mL; further, the pore size regulator is preferably 1,3,5-triisopropylbenzene, and the usage amount is 0 g;

[0091] Step S13: mixing the first solution and the second solution, stirring them evenly, and then adding them to a polytetrafluoroethylene-lined reactor, heating and stirring to react; after the reaction is completed, washing the mixture with deionized water and acetone respectively, and centrifuging to obtain an intermediate product;

[0092] Specifically, the heating temperature is 200° C. and the reaction time is 12 h.

[0093] Step S14: calcining the intermediate product at a high temperature to remove the template to obtain a mesoporous silica material;

[0094] Specifically, the temperature is 600° C. and the calcination is 6 h.

[0095] Step S15: Add 2 g of mesoporous silica material and 200 ml of toluene solution to a three-necked flask and ultrasonically disperse for 10 minutes; then place the three-necked flask in an oil bath, heat to 120° C., add a silane coupling agent dropwise, and condense and reflux for 15 hours; after the reaction is completed, wash the precipitate with ethanol and water respectively, centrifuge and dry to obtain a modified mesoporous silica material, i.e., an acid scavenger.

[0096] Specifically, the aminosilane coupling agent is preferably diethylenetriaminopropyltrimethoxysilane (KH-892); the amount used is 2 g.

[0097] Example 4

[0098] The anti-PID encapsulation EVA film provided in this embodiment includes the following raw materials in parts by weight:

[0099] 100 parts of EVA resin, 1 part of 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, 0.3 parts of trimethylolpropane trimethacrylate, 0.3 parts of pentaerythritol triacrylate, 0.4 parts of vinyltriethoxysilane, 1.0 parts of acid scavenger, 0.2 parts of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, 10100.05 parts of hindered phenol antioxidant, and 1680.1 parts of phosphite antioxidant.

[0100] The above mixture was evenly mixed and poured into the extruder for blending and extrusion. The extruder parameters were adjusted, and the temperature from the feed port to the die head was 80°C, 90°C, 95°C, 95°C, 95°C, 90°C, 90°C, the screw speed was 50rpm, the pulling speed was 0.7rpm, and the winding speed was 1.3rpm. After extrusion, cast film, cooling, slitting and winding processes, an EVA film for encapsulation of photovoltaic modules was prepared. The film had a thickness of 0.5mm and a weight of 400g.

[0101] The preparation method of the acid scavenger is the same as that in specific embodiment 1.

[0102] Example 5

[0103] The anti-PID encapsulation EVA film provided in this embodiment includes the following raw materials in parts by weight:

[0104] 100 parts of EVA resin, 1 part of 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, 0.3 parts of trimethylolpropane trimethacrylate, 0.3 parts of pentaerythritol triacrylate, 0.4 parts of vinyltriethoxysilane, 5.0 parts of acid scavenger, 0.2 parts of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, 10100.05 parts of hindered phenol antioxidant, and 1680.1 parts of phosphite antioxidant.

[0105] The above mixture was evenly mixed and poured into the extruder for blending and extrusion. The extruder parameters were adjusted, and the temperature from the feed port to the die head was 80°C, 90°C, 95°C, 95°C, 95°C, 90°C, 90°C, the screw speed was 50rpm, the pulling speed was 0.7rpm, and the winding speed was 1.3rpm. After extrusion, cast film, cooling, slitting and winding processes, an EVA film for encapsulation of photovoltaic modules was prepared. The film had a thickness of 0.5mm and a weight of 400g.

[0106] The preparation method of the acid scavenger is the same as that in specific embodiment 1.

[0107] Example 6

[0108] The anti-PID encapsulation EVA film provided in this embodiment has the same raw material parts as in specific embodiment 1.

[0109] Wherein the acid scavenger is prepared according to the following method:

[0110] Step S11: dissolving urea and cetyltrimethylammonium bromide in deionized water in a certain proportion, and stirring the mixture to form a first solution;

[0111] Specifically, the ratio of urea, hexadecyltrimethylammonium bromide, and solvent is 1 g:2 g:50 mL. Step S12: Evenly mix pentanol and cyclohexane in proportion, add tetraethyl orthosilicate, stir evenly, then add pore size regulator to the mixture, stir evenly, to form a second solution;

[0112] Specifically, the ratio of pentanol, cyclohexane, and tetraethyl orthosilicate is 2.5 mL: 50 mL: 5 mL; further, the pore size regulator is preferably 1,3,5-triisopropylbenzene, and the amount is 2 g;

[0113] Step S13: mixing the first solution and the second solution, stirring them evenly, and then adding them to a polytetrafluoroethylene-lined reactor, heating and stirring to react; after the reaction is completed, washing the mixture with deionized water and acetone respectively, and centrifuging to obtain an intermediate product;

[0114] Specifically, the heating temperature is 200° C. and the reaction time is 12 h.

[0115] Step S14: calcining the intermediate product at a high temperature to remove the template to obtain a mesoporous silica material;

[0116] Specifically, the temperature is 600° C. and the calcination is 6 h.

[0117] Step S15: Add 2 g of mesoporous silica material and 200 ml of toluene solution to a three-necked flask and ultrasonically disperse for 10 minutes; then place the three-necked flask in an oil bath, heat to 120° C., add a silane coupling agent dropwise, and condense and reflux for 15 hours; after the reaction is completed, wash the precipitate with ethanol and water respectively, centrifuge and dry to obtain a modified mesoporous silica material, i.e., an acid scavenger.

[0118] Specifically, the aminosilane coupling agent is 3-aminopropyltriethoxysilane (KH-550); the amount used is 2 g.

[0119] Example 7

[0120] The anti-PID encapsulation EVA film provided in this embodiment includes the following raw materials in parts by weight:

[0121] 100 parts of EVA resin, 1 part of 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, 0.3 parts of trimethylolpropane trimethacrylate, 0.3 parts of pentaerythritol triacrylate, 0.4 parts of vinyltriethoxysilane, 3.0 parts of acid scavenger, 0.05 parts of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, 0.05 parts of hindered phenol antioxidant 1010, and 0.1 parts of phosphite antioxidant.

[0122] The above mixture was evenly mixed and poured into the extruder for blending and extrusion. The extruder parameters were adjusted, and the temperature from the feed port to the die head was 80°C, 90°C, 95°C, 95°C, 95°C, 90°C, 90°C, the screw speed was 50rpm, the pulling speed was 0.7rpm, and the winding speed was 1.3rpm. After extrusion, cast film, cooling, slitting and winding processes, an EVA film for encapsulation of photovoltaic modules was prepared. The film had a thickness of 0.5mm and a weight of 400g.

[0123] The preparation method of the acid scavenger is the same as that in specific embodiment 1.

[0124] Comparative Example 1

[0125] The anti-PID encapsulation EVA film provided in this embodiment includes the following raw materials in parts by weight:

[0126] 100 parts of EVA resin, 1 part of 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, 0.3 parts of trimethylolpropane trimethacrylate, 0.3 parts of pentaerythritol triacrylate, 0.4 parts of vinyltriethoxysilane, 0.2 parts of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, 10100.05 parts of hindered phenol antioxidant, and 1680.1 parts of phosphite antioxidant.

[0127] The above mixture was evenly mixed and poured into the extruder for blending and extrusion. The extruder parameters were adjusted, and the temperature from the feed port to the die head was 80°C, 90°C, 95°C, 95°C, 95°C, 90°C, 90°C, the screw speed was 50rpm, the pulling speed was 0.7rpm, and the winding speed was 1.3rpm. After extrusion, cast film, cooling, slitting and winding processes, an EVA film for encapsulation of photovoltaic modules was prepared. The film had a thickness of 0.5mm and a weight of 400g.

[0128] Comparative Example 2

[0129] The anti-PID encapsulation EVA film provided in this embodiment has the same raw material parts as in specific embodiment 1.

[0130] The acid scavenger is nano silicon dioxide.

[0131] Comparative Example 3

[0132] The anti-PID encapsulation EVA film provided in this embodiment has the same raw material parts as in specific embodiment 1.

[0133] Wherein the acid scavenger is prepared according to the following method:

[0134] Step S11: dissolving urea and cetyltrimethylammonium bromide in deionized water in a certain proportion, and stirring the mixture to form a first solution;

[0135] Specifically, the usage ratio of urea, hexadecyltrimethylammonium bromide, and solvent is 1 g:2 g:50 mL.

[0136] Step S12: Pentanol and cyclohexane are mixed uniformly in proportion, tetraethyl orthosilicate is added, and the mixture is stirred uniformly. Then, a pore size regulator is added to the mixture and the mixture is stirred uniformly to form a second solution;

[0137] Specifically, the ratio of pentanol, cyclohexane, and tetraethyl orthosilicate is 2.5 mL: 50 mL: 5 mL; further, the pore size regulator is preferably 1,3,5-triisopropylbenzene, and the amount is 2 g;

[0138] Step S13: mixing the first solution and the second solution, stirring them evenly, and then adding them to a polytetrafluoroethylene-lined reactor, heating and stirring to react; after the reaction is completed, washing the mixture with deionized water and acetone respectively, and centrifuging to obtain an intermediate product;

[0139] Specifically, the heating temperature is 200° C. and the reaction time is 12 h.

[0140] Step S14: calcining the intermediate product at a high temperature to remove the template to obtain mesoporous silica, i.e., an acid scavenger;

[0141] Specifically, the temperature is 600° C. and the calcination is 6 h.

[0142] Comparative Example 4

[0143] The anti-PID encapsulation EVA film provided in this embodiment includes the following raw materials in parts by weight:

[0144] 100 parts of EVA resin, 1 part of 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, 0.3 parts of trimethylolpropane trimethacrylate, 0.3 parts of pentaerythritol triacrylate, 0.4 parts of vinyltriethoxysilane, 5.0 parts of acid scavenger, 0.2 parts of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, 10100.05 parts of hindered phenol antioxidant, and 1680.1 parts of phosphite antioxidant.

[0145] The above mixture was evenly mixed and poured into the extruder for blending and extrusion. The extruder parameters were adjusted, and the temperature from the feed port to the die head was 80°C, 90°C, 95°C, 95°C, 95°C, 90°C, 90°C, the screw speed was 50rpm, the pulling speed was 0.7rpm, and the winding speed was 1.3rpm. After extrusion, cast film, cooling, slitting and winding processes, an EVA film for encapsulation of photovoltaic modules was prepared. The film had a thickness of 0.5mm and a weight of 400g.

[0146] The preparation method of the acid scavenger is the same as that of Comparative Example 2.

[0147] Comparative Example 5

[0148] The anti-PID encapsulation EVA film provided in this embodiment includes the following raw materials in parts by weight:

[0149] 100 parts of EVA resin, 0.3 parts of trimethylolpropane trimethacrylate, 0.3 parts of pentaerythritol triacrylate, 0.4 parts of vinyl triethoxysilane, 0.2 parts of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, 10100.05 parts of hindered phenol antioxidant, 1680.1 parts of phosphite antioxidant, 2.0 parts of acid scavenger, and 2.0 parts of diethylenetriaminopropyltrimethoxysilane.

[0150] The above mixture was evenly mixed and poured into the extruder for blending and extrusion. The extruder parameters were adjusted, and the temperature from the feed port to the die head was 80°C, 90°C, 95°C, 95°C, 95°C, 90°C, 90°C, the screw speed was 50rpm, the pulling speed was 0.7rpm, and the winding speed was 1.3rpm. After extrusion, cast film, cooling, slitting and winding processes, an EVA film for encapsulation of photovoltaic modules was prepared. The film had a thickness of 0.5mm and a weight of 400g.

[0151] The preparation method of the acid scavenger is the same as that of Comparative Example 2.

[0152] Comparative Example 6

[0153] The anti-PID encapsulation EVA film provided in this embodiment includes the following raw materials in parts by weight:

[0154] 100 parts of EVA resin, 0.3 parts of trimethylolpropane trimethacrylate, 0.3 parts of pentaerythritol triacrylate, 0.4 parts of vinyl triethoxysilane, 3.0 parts of acid scavenger, 0.2 parts of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, 10100.05 parts of hindered phenol antioxidant, and 1680.1 parts of phosphite antioxidant.

[0155] The above mixture was evenly mixed and poured into the extruder for blending and extrusion. The extruder parameters were adjusted, and the temperature from the feed port to the die head was 80°C, 90°C, 95°C, 95°C, 95°C, 90°C, 90°C, the screw speed was 50rpm, the pulling speed was 0.7rpm, and the winding speed was 1.3rpm. After extrusion, cast film, cooling, slitting and winding processes, an EVA film for encapsulation of photovoltaic modules was prepared. The film had a thickness of 0.5mm and a weight of 400g.

[0156] The preparation method of the acid scavenger is the same as that in Example 1.

[0157] Comparative Example 7

[0158] The anti-PID encapsulation EVA film provided in this embodiment includes the following raw materials in parts by weight:

[0159] 100 parts of EVA resin, 1 part of 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, 0.4 parts of vinyltriethoxysilane, 3.0 parts of acid scavenger, 0.2 parts of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, 10100.05 parts of hindered phenol antioxidant, and 1680.1 parts of phosphite antioxidant.

[0160] The above mixture was evenly mixed and poured into the extruder for blending and extrusion. The extruder parameters were adjusted, and the temperature from the feed port to the die head was 80°C, 90°C, 95°C, 95°C, 95°C, 90°C, 90°C, the screw speed was 50rpm, the pulling speed was 0.7rpm, and the winding speed was 1.3rpm. After extrusion, cast film, cooling, slitting and winding processes, an EVA film for encapsulation of photovoltaic modules was prepared. The film had a thickness of 0.5mm and a weight of 400g.

[0161] The preparation method of the acid scavenger is the same as that in Example 1.

[0162] The performance tests and evaluations of the above example samples and comparative example samples were performed:

[0163] Sample preparation process: Take two pieces of EVA film and two pieces of glass with a size of 200mm×200mm, and stack and fix the glass, two layers of EVA film, and backboard material from bottom to top. Then put the glass facing down into a vacuum laminator and laminate at 145℃ (vacuum for 6 minutes and lamination for 10 minutes) to obtain a laminate sample with no defects in appearance.

[0164] Component preparation: Take two pieces of EVA film and glass with a size of 300mm×300mm, stack them in the order of glass / encapsulation film / cell / encapsulation film / glass, put them into a vacuum laminator, and laminate them at 145℃ (vacuum for 6 minutes, lamination for 10 minutes) to obtain the component.

[0165] Testing process:

[0166] (1) Degree of crosslinking (D): The crosslinking degree of the film was determined using the xylene extraction method. The EVA film was cut into 3 mm pieces, weighed (w1), and placed in a stainless steel mesh bag (w0). The pieces were immersed in xylene solvent and refluxed at 140°C for 5 h. After reflux, the pieces were removed, dried, and weighed (w2).

[0167]

[0168] (2) Light transmittance measurement: The samples were tested using the spectrophotometric method according to the national standard GB / T29848-2018. The wavelength range of the spectrophotometer was set to 290-1100 nm. Three samples were tested in each group and the average value was calculated.

[0169] The transmittance of the sample was tested before and after the test, and the visible light transmittance retention rate was calculated according to the following formula:

[0170] Retention rate of light transmittance=average light transmittance after the test / average light transmittance before the test×100%.

[0171] (3) UV aging resistance: The obtained EVA film was subjected to an ultraviolet radiation aging test in accordance with the requirements of the International Electrotechnical Commission standard IEC61215-2:2016.

[0172] Test conditions: sample surface temperature 60±5℃, UV wavelength range 280-400nm, sample time with irradiation power cumulative dose meter 60kW·h / m 2 .

[0173] The light transmittance before and after the test was measured, and the visible light transmittance retention rate was calculated according to the following formula:

[0174] Retention rate of light transmittance=average light transmittance after the test / average light transmittance before the test×100%.

[0175] The yellowing index YI of the samples before and after the test was measured according to ASTM E313-2010, and the difference between the yellowing index YI after aging and the yellowing index YI before aging was recorded, namely the yellowing index (△YI).

[0176] (4) PID power attenuation: The PID of photovoltaic modules is tested according to the industry standard IEC62804. The test conditions are: 1000V voltage, temperature 85±2°C, humidity 85±3% RH, and test time 96 hours. The power of the photovoltaic modules is measured before and after the test.

[0177] (5) EL test: Confirm that the test environment, surroundings, and component status meet the test conditions. Adjust the output voltage of the constant current power supply to be consistent with the open circuit voltage of the test component. Adjust the imaging camera's viewing distance and focal length so that the component is clear and complete within the viewing field. The image after imaging should be free of defects such as ghosting and blurring.

[0178] (6) EVA encapsulation film peeling strength: refer to the method described in the current national standard GB / T29848-2018, cut two sample strips with a width of 1 cm on the "glass-EVA encapsulation film-EVA encapsulation film-backboard" test piece, and measure the peeling force F on a tensile testing machine at a tensile speed of 100 mm / min. The 180° peel strength (N / cm) of the sample before and after the test was calculated using the formula.

[0179] (7) Free acid: Aging conditions: temperature 85±2°C, humidity 85±3% RH, time 720 h. ATR was used to measure the ratio of the carbonyl peak area to the carboxyl peak area before and after the test.

[0180] (8) Specific surface area of materials: The specific surface area and pore size distribution of the samples were tested using a fully automatic specific surface and porosity analyzer BET.

[0181] (9) Waterproofness test of EVA film: water vapor transmission rate testing equipment.

[0182] The test results are shown in Table 1:

[0183] Table 1 Sample test data results

[0184]

[0185]

[0186] Table 2 Sample test data results

[0187]

[0188] First, it can be observed from Example 1 and Comparative Examples 1 and 2 in Table 1 that the EVA film of the present invention has excellent adsorption performance for free acetic acid using the homemade acid scavenger. It can be observed from Examples 1-3 and Comparative Examples 2-4 in Table 1 that the porous structure of the homemade acid scavenger of the present invention has excellent free acid adsorption performance; at the same time, the modification of the mesoporous silica with the aminosilane coupling agent also plays an important role in the adsorption of free acid; in addition, the mesoporous silica modified with the aminosilane coupling agent also has a significant impact on its dispersibility in the EVA film.

[0189] Secondly, from Figures 1-6 From Table 2, Examples 1-3 and Comparative Examples 1-4, we can conclude that mesoporous nano-silica modified with aminosilane coupling agents with large specific surface areas tends to have higher porosity, effectively "blocking" the heat transfer pathway within the polymer matrix, resulting in a lower thermal conductivity for the composite material. Therefore, the addition of amino-modified mesoporous nano-silica with a high specific surface area can more effectively block the heat transfer pathway and significantly improve the thermal insulation properties of the substrate.

[0190] From the comparison between Example 1 and Comparative Example 5 in Table 1, it can be clearly seen that the homemade acid scavenger adopted in the present invention is prepared by a chemical synthesis method and exhibits more significant performance advantages compared with the traditional physical blending method.

[0191] From Table 2, it can be concluded that larger pore sizes provide wider channels for gas molecules, significantly improving air permeability. Smaller pore sizes effectively prevent water penetration, thereby improving water resistance. Modifying mesoporous silica with a silane coupling agent containing multiple amino groups, changing its surface properties from hydrophilic to hydrophobic, can improve water resistance while maintaining a certain level of air permeability. This significantly enhances the performance and service life of photovoltaic modules.

[0192] Finally, it can be observed from Examples 1 to 7 and Comparative Examples 1 to 7 that by optimizing the formula design and adjusting the crosslinking density as well as the ratio and dosage of the antioxidant and light stabilizer, the acid removal and anti-PID performance of the product can be enhanced.

[0193] In summary, the high-transmittance, acid-removing and PID-resistant EVA encapsulating film and its preparation method use an aminosilane coupling agent to modify the surface of nano-mesoporous silica, changing its surface properties from hydrophilic to hydrophobic. At the same time, its porous structure has excellent free acid adsorption performance. In addition to being able to adsorb free acid and improve the dispersibility of the acid scavenger in the film, the aminosilane coupling agent can also give the acid scavenger a larger specific surface area, thereby increasing the porosity, and can effectively block the heat transfer path in the polymer matrix, thereby giving the film a lower thermal conductivity coefficient, improving the thermal insulation performance, and ultimately achieving the aging resistance and anti-PID performance of the EVA encapsulating film in a hot and humid environment.

[0194] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A method for preparing an EVA encapsulation film, characterized in that: The steps include: S1: mixing, putting the raw materials into a mixer and mixing and stirring to obtain mixed raw materials; S2 extrusion, pouring the mixed raw materials into a single screw extruder, undergoing melt blending, discharge casting, and roller cooling to obtain an extrudate; S3 film forming, the extruded material is subjected to thickness measurement, edge pressing, shaping, and then edge trimming and winding to obtain EVA encapsulation film; Wherein, the raw materials in S1 include an acid scavenger, and the preparation method of the acid scavenger includes the following steps: S11, dissolving urea and cetyltrimethylammonium bromide in deionized water and stirring to form a first solution; After mixing pentanol and cyclohexane, tetraethyl orthosilicate is added, and after stirring, a pore size regulator is added to the mixture to form a second solution; S12, mixing the first solution and the second solution, stirring and adding the mixture to a polytetrafluoroethylene-lined reactor, stirring and reacting until the mixture is washed with deionized water and acetone, respectively, and centrifuged to obtain an intermediate product; S13, calcining the intermediate product to obtain a mesoporous silica material; S14, placing mesoporous silica into a toluene solution, adding an aminosilane coupling agent dropwise, condensing and refluxing, and after the reaction is completed, washing the precipitate with ethanol and water respectively, and centrifuging to obtain an acid scavenger.

2. The preparation method according to claim 1, wherein The step S1 includes the following raw materials in parts by weight: 100 parts of EVA resin, 0.5-2.0 parts of cross-linking agent, 0.1-2.0 parts of auxiliary cross-linking agent, 0.1-0.5 parts of coupling agent, 0.1-5.0 parts of acid scavenger, 0.1-1.0 parts of light stabilizer, and 0.1-1.0 parts of antioxidant.

3. The preparation method according to claim 1, wherein In step S11, the mass ratio of urea, hexadecyltrimethylammonium bromide, and deionized water is 1:2:

50.

4. The preparation method according to claim 1, wherein In step S11, the volume ratio of pentanol, cyclohexane, and tetraethyl orthosilicate is 2.5:50:

5.

5. The preparation method according to claim 1, wherein In step S11, the pore size regulator is any one of 1,3,5-triisopropylbenzene, methylene blue, sodium trifluoroacetate and sodium perfluorooctanoate; The mass ratio of the pore size regulator to the mixed liquid is not higher than 20:57.

5.

6. The preparation method according to claim 1, wherein The pore size range of the mesoporous silica material after calcination in step S13 is 1.0 to 7.5 nm.

7. The preparation method according to claim 1, wherein The aminosilane coupling agent in step S14 includes any one of 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and diethylenetriaminopropyltrimethoxysilane.

8. The preparation method according to claim 2, wherein The cross-linking agent includes any one of 2,5-dimethyl-2,5-bis(tert-butyl peroxide)hexane, 2,5-dimethyl-2,5-bis(benzoyl peroxy)hexane, tert-butyl peroxycarbonate-2-ethylhexyl ester, tert-butyl peroxyacetate, benzoyl peroxide, lauroyl peroxide, dicumyl peroxide, and 1,1-bis(tert-butyl peroxy)-3,3,5-trimethylcyclohexane; The auxiliary cross-linking agent includes a mixture of any two or more of trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, diallyl phthalate, pentaerythritol triacrylate, propoxylated neopentyl glycol diacrylate, and propoxylated pentaerythritol tetraacrylate; The coupling agent includes any one of γ-mercaptopropyltriethoxysilane, vinyltriethoxysilane, vinyltriisopropylsilane, γ-glycidyloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane; The light stabilizer includes any one of mono(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, 3,5-di-tert-butyl-4-hydroxy-benzoic acid hexadecyl ester, and poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinylethanol) succinate; The antioxidant comprises a mixture of any two or more of hindered phenol antioxidants, aromatic amine antioxidants, phosphite antioxidants, thioether antioxidants and metal passivator antioxidants.

9. An EVA encapsulation film, characterized in that: Prepared by the method according to any one of claims 1 to 8, the EVA encapsulation film meets the following conditions: (1) The free acid ratio of the EVA encapsulation film is less than 3.5; (2) The thermal conductivity of the EVA encapsulation film is lower than 0.25 W / (m·K).

10. A photovoltaic module, characterized in that: It includes a glass layer, an EVA encapsulation film layer, a solar cell sheet, and an EVA encapsulation film layer arranged in sequence; Wherein, the EVA encapsulation film layer adopts the EVA encapsulation film as claimed in claim 9.

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