An encapsulating adhesive film composition for copper grid photovoltaic cells, an encapsulating adhesive film and a preparation method thereof, a copper grid line and a photovoltaic cell

Abstract

The application provides an encapsulation adhesive film composition for a copper grid photovoltaic cell, an encapsulation adhesive film and a preparation method thereof, a copper grid line and a photovoltaic cell, and relates to the field of photovoltaics. The raw materials of the encapsulation adhesive film composition for the copper grid photovoltaic cell include, in parts by weight: 100 parts of a base resin, 1-2 parts of an ultraviolet resistance agent, 0.2-1.5 parts of an initiator, 0.2-1.5 parts of a co-crosslinking agent, 0.1-0.5 parts of an adhesion promoter, 0.1-0.5 parts of a light stabilizer, 0.5-3 parts of a nano barrier material, 0.1-1 parts of a metal passivation agent, 0.2-2.5 parts of an antioxidant, and 2-10 parts of an organic solvent. The antioxidant includes benzotriazole and phosphite. By compounding the antioxidant, the nano barrier material and the passivation agent, the oxidation and electrochemical corrosion of the copper grid line are inhibited, and the water and oxygen barrier performance of the adhesive film is improved.

Description

Technical Field

[0001] This application relates to the photovoltaic field, and more particularly to an encapsulation film composition for copper grid photovoltaic cells, an encapsulation film and its preparation method, copper grid wires, and photovoltaic cells. Background Technology

[0002] The cost of silver grid lines in traditional photovoltaic electrodes is high, silver paste accounts for 30%-50% of the non-silicon cost of photovoltaic cells, and silver is expensive (about $800 / kg); in addition, global silver mine reserves are limited, making it difficult to support the expansion of terawatt-level photovoltaic production capacity.

[0003] Currently, copper grid lines are being used instead of silver grid lines. The price of copper is only about 1% of that of silver, which can significantly reduce electrode costs. Furthermore, copper and silver have similar conductivity; copper's conductivity (5.96 × 10⁻⁶) is significantly lower. 7 S / m) is slightly lower than silver (6.3×10 7 (S / m), but it is sufficient to meet the needs.

[0004] However, copper is easily oxidized and reacts with moisture in the encapsulating film to form Cu(OH)2 or CuO, leading to increased grid resistance and decreased battery efficiency. Traditional EVA films have high moisture permeability and lack directional corrosion inhibition. Existing technologies use a single BTA corrosion inhibitor, but it is prone to migration and failure under long-term humid and hot conditions, and the problem of copper ion diffusion and recombination loss to the silicon substrate has not been solved.

[0005] Therefore, there is an urgent need to provide a film composition to solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of this application is to provide an encapsulation film composition for copper grid photovoltaic cells, an encapsulation film and a method for preparing the same, copper grid lines and photovoltaic cells, in order to solve the above-mentioned problems.

[0007] To achieve the above objectives, the first aspect of this application provides an encapsulating film composition for copper grid photovoltaic cells, the raw materials of which, by weight, comprise: The composition includes: 100 parts matrix resin, 1-2 parts UV stabilizer, 0.2-1.5 parts initiator, 0.2-1.5 parts co-crosslinking agent, 0.1-0.5 parts tackifier, 0.1-0.5 parts light stabilizer, 0.5-3 parts nano-barrier material, 0.1-1 part metal passivator, 0.2-2.5 parts antioxidant, and 2-10 parts organic solvent. The antioxidants include benzotriazole and phosphites.

[0008] Optionally, the encapsulating film composition for copper grid photovoltaic cells satisfies at least one of the following conditions: A. The matrix resin includes ethylene-vinyl acetate copolymer and / or ethylene-α-olefin copolymer; B. The UV stabilizer includes hydroxybenzotriazole and / or nano-titanium dioxide; C. The initiator includes one or more of the following: dicarbonate peroxides, acyl peroxides, ester peroxides, and ketal peroxides; D. The co-crosslinking agent includes multifunctional acrylate compounds; E. The tackifier comprises one or more of γ-methacryloyloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane, N-(2-aminoethyl-3-aminopropyl)trimethoxysilane, 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane and methylpropylaminopropoxypropyltrimethoxysilane or their corresponding oligomers; F. The light stabilizer includes hindered amine light stabilizers; G. The nanobarrier material includes modified graphene oxide and / or modified nano-montmorillonite; H. The metal passivating agent includes organophosphonic acid compounds and / or thiols; I. The mass ratio of the oxidant to the metal passivating agent is 2-4:1.

[0009] Optionally, the encapsulating film composition for copper grid photovoltaic cells satisfies at least one of the following conditions: A. The co-crosslinking agent includes one or more of triallyl isocyanurate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, and propoxylated trimethylolpropane triacrylate. B. The particle size of the nanobarrier material is 50nm-200nm; C. The mass ratio of the benzotriazole to the phosphite is 1:1-3.

[0010] A second aspect of this application provides an encapsulating film for copper grid photovoltaic cells, prepared from the aforementioned encapsulating film composition for copper grid photovoltaic cells.

[0011] Optionally, the encapsulating film for copper grid photovoltaic cells satisfies at least one of the following conditions: A. The concentration of the antioxidant increases in a gradient along the outermost edge of the encapsulating film to the copper gate interface; B. The thickness of the encapsulating film used for copper grid photovoltaic cells is 0.3-0.6 mm.

[0012] Optionally, the antioxidant concentration at the copper gate interface is 20%-30% higher than the antioxidant concentration on the outermost side of the encapsulating film.

[0013] A third aspect of this application provides a method for preparing the encapsulating film for copper grid photovoltaic cells, comprising: The raw materials are mixed to obtain a mixture, the mixture is vacuum degassed to obtain a degassed mixture, and the degassed mixture is cast to obtain an encapsulation film for copper grid photovoltaic cells.

[0014] Optionally, the method for preparing the encapsulating film for copper grid photovoltaic cells satisfies at least one of the following conditions: A. The mixture includes: The matrix resin, the initiator, and the crosslinking agent are first mixed to obtain a first mixture; The UV stabilizer, the thickener, the light stabilizer, the metal passivator, the antioxidant, and the organic solvent are mixed in a second way to obtain a second mixture; The first mixture, the nano barrier material, and the second mixture are then mixed in a third mixture. The temperature of the first mixing is 80℃-100℃, the rotation speed is 50rpm-100rpm, and the time is 10min-20min; B. The vacuum degree during the vacuum degassing process is ≤0.1MPa, and the time is 10-15min; C. The degassing direction of the vacuum degassing is perpendicular to the preset copper grid interface.

[0015] A fourth aspect of this application provides a copper grid line, including the encapsulating film for copper grid photovoltaic cells.

[0016] The fifth aspect of this application provides a photovoltaic cell, including the aforementioned copper grid lines.

[0017] Compared with the prior art, the beneficial effects of this application include: The encapsulation film composition for copper grid photovoltaic cells provided in this application, through the compounding of antioxidants, nano-barrier materials, and passivators, synergistically inhibits the oxidation and electrochemical corrosion of copper grid lines, while simultaneously improving the water and oxygen barrier performance of the film. Specifically, the nitrogen heterocyclic structure in the benzotriazole (BTA) molecule of the antioxidant can form a dense [Cu(I)-BTA] complex protective film on the copper surface through chemical adsorption, blocking direct contact between copper and oxygen and water vapor, and inhibiting the anodic oxidation reaction. The phosphite acts by decomposing hydroperoxide (ROOH), blocking the free radical chain reaction, and complexing copper ions (Cu... 2+), inhibiting its catalytic oxidation activity and reducing the reaction rate; in addition, phosphites scavenge free radicals and complex Cu in the bulk phase of the film. 2+ BTA forms a physical-chemical adsorption film on the copper surface, creating a dual "bulk-interface" protection. When the BTA film is partially damaged, the Cu complexed with phosphite... 2+ Reduce its catalytic oxidation to buy time for BTA re-adsorption; phosphite neutralizes acidic substances generated by oxidation (such as H+). + This maintains a neutral environment and delays the acidic hydrolysis of the BTA membrane.

[0018] The encapsulation film for copper grid photovoltaic cells provided in this application has good barrier properties and can effectively inhibit the oxidation and electrochemical corrosion of copper grid lines.

[0019] The method for preparing the encapsulating film for copper grid photovoltaic cells provided in this application uses readily available raw materials and has a simple process.

[0020] The copper grid wires and photovoltaic cells provided in this application have good corrosion resistance and long service life. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0022] Figure 1 This is a diagram of the photovoltaic module after DH1000h in Example 1; Figure 2 This is a diagram of the photovoltaic module after DH1000h in Example 2; Figure 3 The image shows the photovoltaic module after DH1000h for Comparative Example 1. Detailed Implementation

[0023] As used in this article: "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0024] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0025] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0026] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0027] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (where K is any number representing a multiplier). It is important to understand that, unlike parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0028] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0029] The first aspect of this application provides an encapsulating film composition for copper grid photovoltaic cells, wherein the raw materials, by weight, include: The composition includes: 100 parts matrix resin, 1-2 parts UV stabilizer, 0.2-1.5 parts initiator, 0.2-1.5 parts co-crosslinking agent, 0.1-0.5 parts tackifier, 0.1-0.5 parts light stabilizer, 0.5-3 parts nano-barrier material, 0.1-1 part metal passivator, 0.2-2.5 parts antioxidant, and 2-10 parts organic solvent. Optionally, the raw materials in the encapsulation film composition for copper grid photovoltaic cells, by weight, include: an anti-UV agent of any value between 1 part, 1.5 parts, 2 parts, or 1-2 parts; an initiator of any value between 0.2 parts, 1 part, 1.5 parts, or 0.2-1.5 parts; a co-crosslinking agent of any value between 0.2 parts, 1 part, 1.5 parts, or 0.2-1.5 parts; a tackifier of any value between 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, or 0.1-0.5 parts; and a light stabilizer of 0.1 parts. The amounts of the following components are specified: 0.1, 0.2, 0.3, 0.4, 0.5, or any value between 0.1 and 0.5; the amounts of the nano-barrier material are specified: 0.5, 1, 2, 3, or any value between 0.5 and 3; the amounts of the metal passivator are specified: 0.1, 0.5, 1, or any value between 0.1 and 1; the amounts of the antioxidant are specified: 0.2, 1, 2, 2.5, or any value between 0.2 and 2.5; and the amounts of the organic solvent are specified: 2, 4, 6, 8, 10, or any value between 2 and 10. The antioxidants include benzotriazole and phosphites.

[0030] In some embodiments, the encapsulating film composition for copper grid photovoltaic cells satisfies at least one of the following conditions: A. The matrix resin includes ethylene-vinyl acetate copolymer and / or ethylene-α-olefin copolymer; B. The UV stabilizer includes hydroxybenzotriazole and / or nano-titanium dioxide; C. The initiator includes one or more of the following: dicarbonate peroxides, acyl peroxides, ester peroxides, and ketal peroxides; D. The co-crosslinking agent includes multifunctional acrylate compounds; E. The tackifier comprises one or more of γ-methacryloyloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane, N-(2-aminoethyl-3-aminopropyl)trimethoxysilane, 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane and methylpropylaminopropoxypropyltrimethoxysilane or their corresponding oligomers; F. The light stabilizer includes hindered amine light stabilizers; G. The nanobarrier material includes modified graphene oxide and / or modified nano-montmorillonite; In some embodiments, after modification with a silane coupling agent, graphene oxide or nano-montmorillonite carries amino groups (-NH2) on its surface, which form hydrogen bonds with the copper gate oxide layer (CuO), thereby improving the interfacial bonding strength; the amount of modifier used is 1%-3% of the mass of graphene oxide or nano-montmorillonite; Preferred nanobarrier materials include modified graphene oxide, whose two-dimensional sheet structure is arranged in parallel in the film, extending the water and oxygen permeation path (reducing permeability by 60%-80%); and the π-π conjugated structure of modified graphene oxide can adsorb benzotriazole molecules, achieving targeted and sustained release of antioxidants. H. The metal passivating agent includes organophosphonic acid compounds and / or thiols, where the thiols (-SH) in the thiols form dense copper thiolate (Cu-SR) self-assembled monolayers (SAMs) on the copper surface, blocking oxidation and electrochemical corrosion; chelating free Cu 2+ This prevents it from diffusing into the silicon substrate and causing recombination loss; when the thiol film is locally damaged, the unreacted -SH groups can be re-adsorbed to repair the interface.

[0031] It is important to note that when the metal passivating agent includes organophosphonic acid compounds, the phosphonic acid groups react with free Cu. 2+ A stable complex is formed to prevent its migration to the silicon substrate and subsequent recombination loss; and an amorphous copper phosphate film (Cu-PO4) is formed on the copper surface to inhibit electrochemical corrosion reactions. I. The mass ratio of the oxidant to the metal passivating agent is 2-4:1.

[0032] Optionally, the mass ratio of oxidant to metal passivator can be any value between 2:1, 3:1, 4:1 or 2-4:1.

[0033] It is important to note that the oxidation and corrosion resistance of the encapsulation film composition used in copper grid photovoltaic cells is achieved through a three-level protection network of "adsorption-barrier-chelation". First, the first level (interfacial adsorption): the antioxidant forms a molecular film on the copper surface, inhibiting initial oxidation. Second, the second level (physical barrier): nanomaterials block water and oxygen permeation; the two-dimensional layered structure of the nanomaterials extends the water and oxygen permeation path ("maze effect"), delaying the aging of the BTA protective film; material properties drive selective migration, further delaying the aging of the antioxidant molecular film. Third, the third level (ion chelation): a metal passivator captures free Cu that has penetrated the barrier. 2 + To prevent deep corrosion.

[0034] In some embodiments, the encapsulating film composition for copper grid photovoltaic cells satisfies at least one of the following conditions: A. The co-crosslinking agent includes one or more of triallyl isocyanurate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, and propoxylated trimethylolpropane triacrylate. B. The particle size of the nanobarrier material is 50nm-200nm; Optionally, the particle size of the nanobarrier material can be any value between 50nm, 100nm, 150nm, 200nm, or 50nm-200nm; C. The mass ratio of the benzotriazole to the phosphite is 1:1-3.

[0035] Optionally, the mass ratio of benzotriazole to phosphite can be any value between 1:1, 1:2, 1:3, or 1:1-3.

[0036] A second aspect of this application provides an encapsulating film for copper grid photovoltaic cells, prepared from the aforementioned encapsulating film composition for copper grid photovoltaic cells.

[0037] In some embodiments, the encapsulating film for copper grid photovoltaic cells satisfies at least one of the following conditions: A. The concentration of the antioxidant increases in a gradient along the outermost edge of the encapsulating film to the copper gate interface; B. The thickness of the encapsulating film used for copper grid photovoltaic cells is 0.3-0.6 mm.

[0038] Optionally, the thickness of the encapsulating film used for copper grid photovoltaic cells can be any value between 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, or 0.3-0.6 mm.

[0039] In some embodiments, the antioxidant concentration at the copper gate interface is 20%-30% higher than the antioxidant concentration on the outermost side of the encapsulating film.

[0040] Optionally, the antioxidant concentration at the copper gate interface can be higher than the antioxidant concentration on the outermost side of the encapsulating film by any value between 20%, 25%, 30%, or 20%-30%.

[0041] A third aspect of this application provides a method for preparing the encapsulating film for copper grid photovoltaic cells, comprising: The raw materials are mixed to obtain a mixture, the mixture is vacuum degassed to obtain a degassed mixture, and the degassed mixture is cast to obtain an encapsulation film for copper grid photovoltaic cells.

[0042] In some embodiments, the method for preparing the encapsulating film for copper grid photovoltaic cells satisfies at least one of the following conditions: A. The mixture includes: The matrix resin, the initiator, and the crosslinking agent are first mixed to obtain a first mixture; The UV stabilizer, the thickener, the light stabilizer, the metal passivator, the antioxidant, and the organic solvent are mixed in a second way to obtain a second mixture; The first mixture, the nano barrier material, and the second mixture are then mixed in a third mixture. The temperature of the first mixing is 80℃-100℃, the rotation speed is 50rpm-100rpm, and the time is 10min-20min; Optionally, the temperature of the first mixture can be any value between 80℃, 90℃, 100℃ or 80℃-100℃, the rotation speed can be any value between 50rpm, 60rpm, 70rpm, 80rpm, 90rpm, 100rpm or 50rpm-100rpm, and the time can be any value between 10min, 15min, 20min or 10min-20min. B. The vacuum degree during the vacuum degassing process is ≤0.1MPa, and the time is 10-15min; Optionally, the vacuum degree can be any value of 0.1MPa, 0.01MPa, 0.001MPa or ≤0.1MPa, and the time can be any value of 10min, 12min, 15min or 10-15min. C. The degassing direction of the vacuum degassing is perpendicular to the preset copper grid interface.

[0043] It is important to note that the vacuum degassing operation perpendicular to the copper gate interface creates a pressure gradient, which drives the antioxidant to migrate towards the copper gate interface.

[0044] It should be noted that antioxidants have small molecular weights and high diffusion rates in the resin matrix. During vacuum degassing, they preferentially evaporate from the copper grid side along with the organic solvent, driving them to migrate towards the interface. Furthermore, the nitrogen heterocycles in the antioxidants form Cu(I)-BTA complexes with the copper grid oxide layer (CuO), which are preferentially enriched at the interface.

[0045] A fourth aspect of this application provides a copper grid line, including the encapsulating film for copper grid photovoltaic cells.

[0046] The fifth aspect of this application provides a photovoltaic cell, including the aforementioned copper grid lines.

[0047] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0048] Example 1 The first aspect of this embodiment provides an encapsulating film composition for copper grid photovoltaic cells, the raw materials of which, by weight, include: The matrix resin consists of 100 parts of ethylene-vinyl acetate copolymer (VA content 28%, melt index 25, purchased from Lianhong), 0.8 parts of tert-butyl peroxycarbonate-2-ethylhexyl ester initiator, 0.8 parts of crosslinking agent (tracene isocyanurate and trimethylolpropane triacrylate in a mass ratio of 1:1), 0.2 parts of vinyltriethoxysilane tackifier, 0.3 parts of sebacic acid bis-2,2,6,6-tetramethylpiperidinol ester, 0.8 parts of UV stabilizer UV-P, 0.7 parts of organophosphonic acid EDTMPA metal passivator, 1.5 parts of antioxidant (benzotriazole BTA and phosphite in a mass ratio of 1:1.5), modified graphene oxide nanomaterial (surface modified by silane coupling agent KH-550, the amount of modifier is 2% of the mass of the nanographene oxide, and the particle size is 100nm), and 5 parts of anhydrous ethanol. The second aspect of this embodiment provides an encapsulating film for copper grid photovoltaic cells and a method for preparing the same, with the specific steps as follows: The matrix resin, initiator and crosslinking agent were mixed in a mixer at 90°C, 75 rpm and 15 min to obtain the first mixture. UV stabilizer, thickener, light stabilizer, metal passivator and antioxidant are dissolved in an organic solvent, ultrasonically dispersed and then added together with nano barrier material to the first mixture to obtain the second mixture; The second mixture was subjected to vacuum degassing, with the degassing direction perpendicular to the preset copper grid interface. The vacuum degree was maintained at ≤0.1MPa for 12 minutes. The film was then prepared by casting process, with the thickness controlled at 0.4mm. After cooling, the film was wound up to obtain the encapsulation film for copper grid photovoltaic cells.

[0049] The concentration of antioxidants increases in a gradient from the outermost edge of the encapsulation film used in copper grid photovoltaic cells to the copper grid interface. The mass concentration of antioxidants at the copper grid interface of the encapsulation film used in copper grid photovoltaic cells is 25% higher than the mass concentration of antioxidants at the outermost edge of the encapsulation film.

[0050] In the third aspect of this embodiment, a photovoltaic module is produced by encapsulating the welded copper grid solar cells with the aforementioned encapsulating film, and then performing processes such as lamination, connector installation, and frame installation to obtain the finished photovoltaic module.

[0051] Example 2 The difference from Example 1 is that the mass ratio of benzotriazole to phosphite is 1:2.

[0052] Example 3 The difference from Example 1 is that the nanobarrier material is modified nano-montmorillonite.

[0053] Comparative Example 1 The difference from Example 1 is that a traditional EVA film is used.

[0054] Comparative Example 2 The difference from Example 1 is that benzotriazole is not added.

[0055] Comparative Example 3 The difference from Example 1 is that no phosphite is added.

[0056] Comparative Example 4 The difference from Example 1 is that no metal passivating agent is added.

[0057] Comparative Example 5 The difference from Example 1 is that no nano-barrier material is added.

[0058] The photovoltaic modules prepared in the above embodiments and comparative examples were subjected to performance tests before and after DH1000h. The test results are shown in Table 1.

[0059] Example 1: Photovoltaic modules after DH1000h, as shown Figure 1 As shown, the photovoltaic module after DH1000h in Example 2 is as follows: Figure 2 As shown, the photovoltaic module of Comparative Example 1 after DH1000h is as follows Figure 3 As shown.

[0060] DH1000h test: ambient temperature: 85℃, ambient humidity: 85%RH, test time: 1000+48H, reference standard: IEC61215-2.

[0061] Table 1 Performance Tests

[0062] analyze: As shown in Table 1, after 1000 hours of DH aging test, the power attenuation of Examples 1, 2, and 3 was all within 1.55%, and the attenuation of electrical parameters such as Voc, Isc, Vmp, Imp, and FF was also low. In contrast, after 1000 hours of DH aging test, the power attenuation of Comparative Examples 1, 2, 3, 4, and 5 was ≥3.99%, and the attenuation of electrical parameters such as Voc, Isc, Vmp, Imp, and FF was higher than that of Examples 1-3. This indicates that the electrical performance of Examples 1-3 under high temperature and high humidity conditions is better than that of the Comparative Examples.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0064] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the foregoing claims, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A film composition for encapsulating copper grid photovoltaic cells, characterized in that, Its raw materials, by weight, include: The composition includes: 100 parts matrix resin, 1-2 parts UV stabilizer, 0.2-1.5 parts initiator, 0.2-1.5 parts co-crosslinking agent, 0.1-0.5 parts tackifier, 0.1-0.5 parts light stabilizer, 0.5-3 parts nano-barrier material, 0.1-1 part metal passivator, 0.2-2.5 parts antioxidant, and 2-10 parts organic solvent. The antioxidants include benzotriazole and phosphites.

2. The encapsulating film composition for copper grid photovoltaic cells according to claim 1, characterized in that, At least one of the following conditions must be met: A. The matrix resin includes ethylene-vinyl acetate copolymer and / or ethylene-α-olefin copolymer; B. The UV stabilizer includes hydroxybenzotriazole and / or nano-titanium dioxide; C. The initiator includes one or more of the following: dicarbonate peroxides, acyl peroxides, ester peroxides, and ketal peroxides; D. The co-crosslinking agent includes multifunctional acrylate compounds; E. The tackifier comprises one or more of γ-methacryloyloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane, N-(2-aminoethyl-3-aminopropyl)trimethoxysilane, 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane and methylpropylaminopropoxypropyltrimethoxysilane or their corresponding oligomers; F. The light stabilizer includes hindered amine light stabilizers; G. The nanobarrier material includes modified graphene oxide and / or modified nano-montmorillonite; H. The metal passivating agent includes organophosphonic acid compounds and / or thiols; I. The mass ratio of the oxidant to the metal passivating agent is 2-4:

1.

3. The encapsulating film composition for copper grid photovoltaic cells according to claim 2, characterized in that, At least one of the following conditions must be met: A. The co-crosslinking agent includes one or more of triallyl isocyanurate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, and propoxylated trimethylolpropane triacrylate. B. The particle size of the nanobarrier material is 50nm-200nm; C. The mass ratio of the benzotriazole to the phosphite is 1:1-3.

4. An encapsulating film for copper grid photovoltaic cells, characterized in that, It is prepared from the encapsulating film composition for copper grid photovoltaic cells according to any one of claims 1-3.

5. The encapsulating film for copper grid photovoltaic cells according to claim 4, characterized in that, At least one of the following conditions must be met: A. The concentration of the antioxidant increases in a gradient along the outermost edge of the encapsulating film to the copper gate interface; B. The thickness of the encapsulating film used for copper grid photovoltaic cells is 0.3-0.6 mm.

6. The encapsulating film for copper grid photovoltaic cells according to claim 5, characterized in that, The antioxidant concentration at the copper gate interface is 20%-30% higher than the antioxidant concentration on the outermost side of the encapsulating film.

7. A method for preparing an encapsulating film for copper grid photovoltaic cells according to any one of claims 4-6, characterized in that, include: The raw materials are mixed to obtain a mixture, the mixture is vacuum degassed to obtain a degassed mixture, and the degassed mixture is cast to obtain an encapsulation film for copper grid photovoltaic cells.

8. The method for preparing the encapsulating film for copper grid photovoltaic cells according to claim 7, characterized in that, At least one of the following conditions must be met: A. The mixture includes: The matrix resin, the initiator, and the crosslinking agent are first mixed to obtain a first mixture; The UV stabilizer, the thickener, the light stabilizer, the metal passivator, the antioxidant, and the organic solvent are mixed in a second way to obtain a second mixture; The first mixture, the nano barrier material, and the second mixture are then mixed in a third mixture. The temperature of the first mixing is 80℃-100℃, the rotation speed is 50rpm-100rpm, and the time is 10min-20min; B. The vacuum degree during the vacuum degassing process is ≤0.1MPa, and the time is 10-15min; C. The degassing direction of the vacuum degassing is perpendicular to the preset copper grid interface.

9. A copper grid wire, characterized in that, Includes the encapsulating film for copper grid photovoltaic cells as described in any one of claims 4-6.

10. A photovoltaic cell, characterized in that, Includes the copper grid line as described in claim 9.

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