Packaging adhesive film and photovoltaic module

Abstract

The invention provides a packaging adhesive film and a photovoltaic module. The packaging adhesive film comprises a first bonding layer, a creep-resistant layer and a second bonding layer which are stacked in sequence, the creep-resistant layer comprises the following components in percentage by mass: 0-80 wt% of first matrix resin and 20-100 wt% of functional group modified resin; the first bonding layer and the second bonding layer respectively and independently comprise 0-80 wt% of second matrix resin and 20-100 wt% of silane group modified resin; functional groups in the functional group modified resin comprise a first functional group and a second functional group; and the first functional group and the second functional group can be subjected to a cross-linking reaction at 100-120 DEG C. According to the packaging adhesive film, low-temperature packaging can be realized, and no small-molecule auxiliary agent is left in the packaging adhesive film, so that the stability of the photovoltaic module is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic modules, and in particular to a packaging film and a photovoltaic module. Background Art

[0002] Today, with energy shortages and environmental issues becoming increasingly prominent, it has become an inevitable trend to find renewable, environmentally friendly green energy. Photovoltaic power generation is the process of converting solar energy into electrical energy. It has three advantages: permanence, cleanliness, and flexibility. Compared with traditional thermal power generation, hydropower generation, and nuclear power generation, the preparation process of photovoltaic power generation is simple and highly reproducible, so it has a good development prospect.

[0003] Compared with traditional crystalline silicon cells, perovskite cells have the advantages of low cost, low energy consumption in the preparation process, and high theoretical efficiency. Perovskite cells have developed rapidly in the past few years. Not only has the photoelectric conversion efficiency of small-size cells in laboratory research continued to break records, but the industrialization process has also made great strides forward. Many perovskite battery component manufacturers already have the ability to produce large-size components and have gradually begun to ship in batches. However, the high-temperature stability problem of perovskite cells has not been solved. Specifically, the temperature of the component packaging cannot be higher than 120°C. Therefore, the encapsulation film is required to match the low-temperature lamination process.

[0004] At present, the encapsulation films on the market are mainly divided into two types: cross-linked films and non-cross-linked films. Among them, cross-linked films generally contain cross-linking agents and bridging agents. The cross-linking agent is mostly an organic peroxidant, which decomposes to produce free radicals after heating, initiating cross-linking between the bridging agent and the matrix resin. In order to achieve sufficient cross-linking (cross-linking degree greater than 70%), the encapsulation temperature of the cross-linked film is generally 140℃~160℃. Although the anti-creep effect of the cross-linked film is very good, it exceeds the range that the perovskite battery can withstand, so the cross-linked film is mostly used for the encapsulation of crystalline silicon batteries. In addition, these small molecule additives may also destroy the perovskite battery, thereby affecting the stability of the battery. The non-cross-linked film does not contain a cross-linking agent, there is no cross-linking reaction in the encapsulation process, and the encapsulated film is thermoplastic. Therefore, the anti-creep performance is poor. When the photovoltaic module works outdoors, its internal temperature is high and there is a high risk of creep.

[0005] Therefore, a new packaging film is needed, which can match the low-temperature packaging process, has no small molecule additive residue, and has a good anti-creep effect. Summary of the invention

[0006] The main purpose of the present invention is to provide a packaging film and a photovoltaic module to solve the problem that the packaging film in the prior art is difficult to simultaneously achieve low-temperature lamination, no residual additives and good creep resistance.

[0007] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided a packaging film, which comprises a first bonding layer, an anti-creep layer and a second bonding layer stacked in sequence; in terms of mass percentage, the anti-creep layer comprises 0 to 80 wt % of a first matrix resin and 20 to 100 wt % of a functional group modified resin; the first bonding layer and the second bonding layer each independently comprise 0 to 80 wt % of a second matrix resin and 20 to 100 wt % of a silane group modified resin; the functional groups in the functional group modified resin comprise a first functional group and a second functional group; the first functional group and the second functional group can undergo a cross-linking reaction at 100 to 120° C.

[0008] Furthermore, the mass proportion of the above-mentioned first functional group in the functional group modified resin is 0.5 to 5wt%; and / or, the mass proportion of the second functional group in the functional group modified resin is 0.5 to 5wt%; preferably, the mass ratio of the first functional group to the second functional group is 1:10 to 10:1; preferably, the first functional group and the second functional group are each independently selected from any one of hydroxyl, carboxyl, amino, epoxy, sulfonic acid, amide, cyano, isocyanate, acyl chloride, thiol and anhydride, and the first functional group can react with the second functional group.

[0009] Furthermore, the thickness of the first adhesive layer and the second adhesive layer is independently 50-200 μm; and / or the thickness of the anti-creep layer is 100-500 μm; preferably, the thickness ratio of the first adhesive layer, the anti-creep layer and the second adhesive layer is 50-150:100-300:50-150.

[0010] Furthermore, the mass ratio of the first base resin to the functional group modified resin is 60-80:20-40.

[0011] Furthermore, the mass percentage of the silane group in the above silane group modified resin is 0.5wt% to 10wt%; preferably, the structural formula of the silane group is Wherein, R is selected from any one of C1-C6 alkyl groups, and X and Y are each independently selected from any one of hydrogen, C1-C6 alkyl groups and C1-C6 alkoxy groups.

[0012] Furthermore, the mass ratio of the second base resin to the silane group modified resin is 60-80:20-40.

[0013] Further, the peak melting point of the first matrix resin is 45-115° C.; and / or the first matrix resin is selected from a matrix resin with a density of 0.85-0.97 g / cm 3any one or more of polyethylene, ethylene and vinyl acetate copolymer, ethylene and α-olefin copolymer, ethylene and acrylic acid copolymer, ethylene and methyl acrylate copolymer, ethylene and ethyl acrylate copolymer, ethylene and methacrylic acid copolymer, ethylene and methyl methacrylate copolymer; and / or the peak melting point of the functional group modified resin is 40 to 115° C.; and / or the resin in the functional group modified resin is selected from a resin with a density of 0.85 to 0.97 g / cm 3 Any one or more of polyethylene, ethylene and vinyl acetate copolymer, ethylene and α-olefin copolymer, ethylene and acrylic acid copolymer, ethylene and methyl acrylate copolymer, ethylene and ethyl acrylate copolymer, ethylene and methacrylic acid copolymer, and ethylene and methyl methacrylate copolymer.

[0014] Further, the peak melting point of the above-mentioned second matrix resin is 45-115°C; and / or the second matrix resin is selected from any one or more of ethylene acetate and vinyl ester copolymers, ethylene and propylene copolymers, ethylene and butene copolymers, ethylene and pentene copolymers, ethylene and hexene copolymers, and ethylene and octene copolymers; and / or the peak melting point of the silane group modified resin is 40-115°C; and / or the resin in the silane group modified resin is selected from any one or more of ethylene acetate and vinyl ester copolymers, ethylene and propylene copolymers, ethylene and butene copolymers, ethylene and pentene copolymers, ethylene and hexene copolymers, and ethylene and octene copolymers.

[0015] According to another aspect of the present invention, a photovoltaic module is provided, wherein the photovoltaic module comprises at least one layer of cross-linked encapsulation film, wherein the cross-linked encapsulation film is formed by encapsulating the aforementioned encapsulation film.

[0016] Furthermore, the cross-linking degree of the cross-linked packaging film is greater than 20 wt %.

[0017] By applying the technical solution of the present invention, the first adhesive layer and the second adhesive layer are used to ensure that the encapsulation film has good adhesion to the glass, thereby improving the reliability of the photovoltaic module, and then reducing the probability of reliability problems such as bubbles and delamination in the photovoltaic module. The first functional group and the second functional group in the anti-creep layer undergo a cross-linking reaction during the encapsulation process of the encapsulation film, thereby improving the cross-linking degree of the encapsulation film, and then improving the anti-creep effect of the encapsulation film. It is preferred to control the first functional group and the second functional group to be able to undergo a cross-linking reaction at the above temperature, which helps to promote the cross-linking reaction of the encapsulation film during the low-temperature encapsulation process. In addition, since the cross-linking of the encapsulation film is achieved by the cross-linking reaction between the first functional group and the second functional group on the modified resin, the anti-creep layer of the present application is free of peroxides and other small molecule additives, thereby helping to avoid the influence of peroxides and other small molecule additives on the batteries in the photovoltaic module. Therefore, the encapsulation film of the present application can achieve low-temperature encapsulation, and there is no small molecule additive residue in the encapsulation film, thereby improving the stability of the photovoltaic module. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1 The schematic diagram of the structure of the packaging film in Example 1 of the present application is shown;

[0020] Figure 2 A schematic structural diagram of a test sample in the creep resistance test of the present application is shown.

[0021] The above drawings include the following reference numerals:

[0022] 1. First bonding layer; 2. Anti-creep layer; 3. Second bonding layer; 4. Hook; 5. Structural adhesive; 6. First glass; 7. Packaging film; 8. Second glass. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] As analyzed in the background technology of this application, the encapsulation film in the prior art has the problem that it is difficult to simultaneously achieve low-temperature lamination, no residual additives, and good creep resistance. In order to solve the above problems, this application provides an encapsulation film and a photovoltaic module.

[0025] In a typical embodiment of the present application, a packaging film is provided, and the structural schematic diagram of the packaging film is as follows: Figure 1As shown, the packaging film includes a first bonding layer 1, an anti-creep layer 2 and a second bonding layer 3 stacked in sequence; in terms of mass percentage, the anti-creep layer 2 includes 0-80wt% of a first matrix resin and 20-100wt% of a functional group modified resin; the first bonding layer 1 and the second bonding layer 3 each independently include 0-80wt% of a second matrix resin and 20-100wt% of a silane group modified resin; the functional group in the functional group modified resin includes a first functional group and a second functional group; the first functional group and the second functional group can undergo a cross-linking reaction at 100-120°C.

[0026] The first adhesive layer and the second adhesive layer are used to ensure that the encapsulation film has good adhesion to the glass, thereby improving the reliability of the photovoltaic module, thereby reducing the probability of reliability problems such as bubbles and delamination in the photovoltaic module. The first functional group and the second functional group in the anti-creep layer undergo a cross-linking reaction during the encapsulation process of the encapsulation film, thereby improving the cross-linking degree of the encapsulation film, thereby improving the anti-creep effect of the encapsulation film. It is preferred to control the first functional group and the second functional group to be able to undergo a cross-linking reaction at the above temperature, which helps to promote the cross-linking reaction of the encapsulation film during the low-temperature encapsulation process. In addition, since the cross-linking of the encapsulation film is achieved by the cross-linking reaction between the first functional group and the second functional group on the modified resin, the anti-creep layer of the present application is free of peroxides and other small molecule additives, thereby helping to avoid the influence of peroxides and other small molecule additives on the batteries in the photovoltaic module. Therefore, the encapsulation film of the present application can achieve low-temperature encapsulation, and there is no small molecule additive residue in the encapsulation film, thereby improving the stability of the photovoltaic module.

[0027] In one embodiment of the present application, the mass proportion of the above-mentioned first functional group in the functional group modified resin is 0.5-5wt%; and / or, the mass proportion of the second functional group in the functional group modified resin is 0.5-5wt%; preferably, the mass ratio of the first functional group to the second functional group is 1:10-10:1; preferably, the first functional group and the second functional group are each independently selected from any one of hydroxyl, carboxyl, amino, epoxy, sulfonic acid, amide, cyano, isocyanate, acyl chloride, thiol and anhydride, and the first functional group can react with the second functional group.

[0028] Preferably, the mass ratio of the first functional group and the second functional group in the functional group modified resin is controlled within the above range, which helps to fully crosslink the first functional group and the second functional group in the functional group modified resin under lamination, thereby improving the crosslinking density of the encapsulation film finally formed. Preferably, the types of the first functional group and the second functional group are controlled independently within the above range, which helps to further improve the crosslinking efficiency of the first functional group and the second functional group. Preferably, the first functional group is carboxyl and / or hydroxyl, and the second functional group is amino and / or epoxy.

[0029] In one embodiment of the present application, the thickness of the first bonding layer 1 and the second bonding layer 3 are each independently 50 to 200 μm; and / or the thickness of the anti-creep layer 2 is 100 to 500 μm; preferably, the ratio of the thickness of the first bonding layer 1, the anti-creep layer 2 and the second bonding layer 3 is 50 to 150:100 to 300:50 to 150.

[0030] If the thickness of the first adhesive layer 1 and the second adhesive layer 3 is too small, it is not conducive to improving the bonding force of the final encapsulation film, so that the encapsulation film has a reliability risk; if the thickness of the first adhesive layer 1 and the second adhesive layer 3 is too large, it is not conducive to improving the anti-creep effect of the final encapsulation film. It is preferred to control the thickness of the first adhesive layer 1 and the second adhesive layer 3 independently within the above range, which helps to make the final encapsulation film have a higher bonding force and a stronger anti-creep effect. If the thickness of the anti-creep layer 2 is too small, it is not conducive to improving the anti-creep effect of the final encapsulation film; if the thickness of the anti-creep layer 2 is too large, it is not conducive to reducing the cost of the final encapsulation film. It is preferred to control the thickness of the anti-creep layer 2 within the above range, which helps to take into account the lower cost and stronger anti-creep effect of the final encapsulation film. It is preferred to control the ratio of the thickness of the first adhesive layer 1, the anti-creep layer 2 and the second adhesive layer 3 within the above range, which helps to further improve the bonding force and anti-creep effect of the final encapsulation film, while reducing the cost of the final encapsulation film.

[0031] In one embodiment of the present application, the mass ratio of the first base resin to the functional group modified resin is 60-80:20-40.

[0032] The mass ratio of the first matrix resin to the functional group-modified resin is preferably controlled within the above range, which helps to improve the anti-creep effect and stability of the finally formed encapsulation film.

[0033] In order to further improve the adhesion of the finally formed encapsulation film, in one embodiment of the present application, the mass proportion of the silane group in the silane group-modified resin is preferably 0.5wt% to 10wt%; the structural formula of the silane group is preferably Wherein, R is selected from any one of C1-C6 alkyl groups, and X and Y are each independently selected from any one of hydrogen, C1-C6 alkyl groups and C1-C6 alkoxy groups.

[0034] In one embodiment of the present application, the mass ratio of the second base resin to the silane group modified resin is 60-80:20-40.

[0035] The mass ratio of the second base resin to the silane group-modified resin is preferably controlled within the above range, which helps to improve the stability and adhesion of the finally formed encapsulation film.

[0036] In one embodiment of the present application, the peak melting point of the first matrix resin is 45-115° C.; and / or the first matrix resin is selected from a matrix resin with a density of 0.85-0.97 g / cm 3 any one or more of polyethylene, ethylene and vinyl acetate copolymer, ethylene and α-olefin copolymer, ethylene and acrylic acid copolymer, ethylene and methyl acrylate copolymer, ethylene and ethyl acrylate copolymer, ethylene and methacrylic acid copolymer, ethylene and methyl methacrylate copolymer; and / or the peak melting point of the functional group modified resin is 40 to 115° C.; and / or the resin in the functional group modified resin is selected from a resin with a density of 0.85 to 0.97 g / cm 3 Any one or more of polyethylene, ethylene and vinyl acetate copolymer, ethylene and α-olefin copolymer, ethylene and acrylic acid copolymer, ethylene and methyl acrylate copolymer, ethylene and ethyl acrylate copolymer, ethylene and methacrylic acid copolymer, and ethylene and methyl methacrylate copolymer.

[0037] Preferably, the peak melting point of the first matrix resin and the type of the first matrix resin are controlled within the above range, which helps to improve the interaction between the anti-creep layer 2 and the first bonding layer 1 and the second bonding layer 3 during the lamination process of the encapsulation film. Preferably, the peak melting point of the functional group-modified resin and the type of resin in the functional group-modified resin are controlled within the above range, which helps to further improve the compatibility between the first matrix resin and the functional group-modified resin.

[0038] In one embodiment of the present application, the peak melting point of the above-mentioned second matrix resin is 45-115°C; and / or, the second matrix resin is selected from any one or more of ethylene acetate and vinyl ester copolymers, ethylene and propylene copolymers, ethylene and butene copolymers, ethylene and pentene copolymers, ethylene and hexene copolymers, and ethylene and octene copolymers; and / or, the peak melting point of the silane group modified resin is 40-115°C; and / or, the resin in the silane group modified resin is selected from any one or more of ethylene acetate and vinyl ester copolymers, ethylene and propylene copolymers, ethylene and butene copolymers, ethylene and pentene copolymers, ethylene and hexene copolymers, and ethylene and octene copolymers.

[0039] Preferably, the peak melting point of the second matrix resin and the type of the second matrix resin are controlled within the above range, which helps to improve the interaction between the contact surfaces of the first adhesive layer 1 and the second adhesive layer 3 and other components in the photovoltaic module during the lamination process of the encapsulation film. Preferably, the peak melting point of the silane group-modified resin and the type of resin in the silane group-modified resin are controlled within the above range, which helps to further improve the compatibility between the second matrix resin and the silane group-modified resin.

[0040] In another typical embodiment of the present application, a photovoltaic module is provided, wherein the photovoltaic module contains at least one layer of cross-linked encapsulation film, wherein the cross-linked encapsulation film is formed by encapsulating the aforementioned encapsulation film.

[0041] Since the cross-linked encapsulation film in the above photovoltaic module is formed by encapsulating the encapsulation film of the present application, the photovoltaic module has good creep resistance.

[0042] In order to further improve the creep resistance of the photovoltaic module, in one embodiment of the present application, the cross-linking degree of the cross-linked encapsulation film is preferably greater than 20 wt %.

[0043] The beneficial effects of the present application will be further illustrated below in conjunction with embodiments.

[0044] Example 1

[0045] In terms of mass percentage, 80wt% of silane-grafted ethylene-butene copolymer and 20wt% of ethylene-octane copolymer are mixed to obtain a mixed raw material for the first bonding layer, wherein the mass proportion of triethoxysilane groups in the silane-grafted ethylene-butene copolymer is 5wt%, the peak melting point of the silane-grafted ethylene-butene copolymer is 71°C, and the peak melting point of the ethylene-octane copolymer is 75°C; 80wt% of carboxyl- and amino-modified ethylene-butene copolymer and 20wt% of ethylene-vinyl acetate copolymer are mixed to obtain a mixed raw material for the anti-creep layer, wherein the mass proportion of carboxyl groups in the carboxyl- and amino-modified ethylene-butene copolymer is 4wt%, and the mass proportion of carboxyl groups in the carboxyl- and amino-modified ethylene-butene copolymer is 6wt%. The mass proportion of amino groups in the ethylene-butene copolymer is 1wt%, the peak melting point of the ethylene-butene copolymer modified by carboxyl and amino groups is 72°C, and the peak melting point of the ethylene-vinyl acetate copolymer is 75°C; 80wt% of the silane-grafted ethylene-butene copolymer is mixed with 20wt% of the ethylene-octane copolymer to obtain a mixed raw material for the second bonding layer, wherein the mass proportion of triethoxysilane in the silane-grafted ethylene-butene copolymer is 5wt%, the peak melting point of the silane-grafted ethylene-butene copolymer is 71°C, and the peak melting point of the ethylene-octane copolymer is 75°C; the mixed raw material for the first bonding layer, the mixed raw material for the anti-creep layer and the mixed raw material for the second bonding layer are co-extruded to obtain the following Figure 1 The packaging film shown is composed of a first adhesive layer 1, an anti-creep layer 2 and a second adhesive layer 3. The thickness of the first adhesive layer 1 is 100 μm, the thickness of the anti-creep layer 2 is 300 μm, and the thickness of the second adhesive layer 3 is 100 μm.

[0046] Example 2

[0047] The difference from Example 1 is that the mass proportion of carboxyl groups in the carboxyl and amino modified ethylene-butene copolymer is 5wt%, and the mass proportion of amino groups in the carboxyl and amino modified ethylene-butene copolymer is 0.5wt%, and finally an encapsulation film is obtained.

[0048] Example 3

[0049] The difference from Example 1 is that the mass proportion of carboxyl groups in the carboxyl and amino modified ethylene-butene copolymer is 0.5wt%, and the mass proportion of amino groups in the carboxyl and amino modified ethylene-butene copolymer is 5wt%, and finally an encapsulation film is obtained.

[0050] Example 4

[0051] The difference from Example 1 is that the mass proportion of carboxyl groups in the carboxyl and amino modified ethylene-butene copolymer is 0.4wt%, and the mass proportion of amino groups in the carboxyl and amino modified ethylene-butene copolymer is 5.5wt%, and finally an encapsulation film is obtained.

[0052] Example 5

[0053] The difference from Example 1 is that a hydroxyl group is used to replace a carboxyl group, and an epoxy group is used to replace an amino group, so that a packaging film is finally obtained.

[0054] Example 6

[0055] The difference from Example 1 is that the thickness of the first adhesive layer 1 is 50 μm, the thickness of the anti-creep layer 2 is 300 μm, and the thickness of the second adhesive layer 3 is 50 μm, and finally a packaging film is obtained.

[0056] Example 7

[0057] The difference from Example 1 is that the thickness of the first adhesive layer 1 is 150 μm, the thickness of the anti-creep layer 2 is 100 μm, and the thickness of the second adhesive layer 3 is 150 μm, and finally a packaging film is obtained.

[0058] Example 8

[0059] The difference from Example 1 is that the thickness of the first adhesive layer 1 is 50 μm, the thickness of the anti-creep layer 2 is 500 μm, and the thickness of the second adhesive layer 3 is 50 μm, and finally a packaging film is obtained.

[0060] Example 9

[0061] The difference from Example 1 is that the mass proportion of the silane group in the silane-grafted ethylene-butylene copolymer is 10wt%, and finally a packaging film is obtained.

[0062] Example 10

[0063] The difference from Example 1 is that the mass proportion of the silane group in the silane-grafted ethylene-butylene copolymer is 0.5wt%, and a packaging film is finally obtained.

[0064] Embodiment 11

[0065] The difference from Example 1 is that the mass proportion of the silane group in the silane-grafted ethylene-butylene copolymer is 0.4wt%, and a packaging film is finally obtained.

[0066] Example 12

[0067] The difference from Example 1 is that, by mass percentage, 60wt% of silane-grafted ethylene-butene copolymer and 40wt% of ethylene-octane copolymer are mixed to obtain a mixed raw material for the first bonding layer, wherein the mass proportion of triethoxysilane groups in the silane-grafted ethylene-butene copolymer is 5wt%; 60wt% of carboxyl and amino-modified ethylene-butene copolymer and 40wt% of ethylene-vinyl acetate copolymer are mixed to obtain a mixed raw material for the anti-creep layer, wherein the mass proportion of carboxyl groups in the carboxyl and amino-modified ethylene-butene copolymer is 4wt%, and the mass proportion of amino groups in the carboxyl and amino-modified ethylene-butene copolymer is 10wt%. The mass proportion of the base is 1wt%; 60wt% of the silane-grafted ethylene-butene copolymer is mixed with 40wt% of the ethylene-octane copolymer to obtain a mixed raw material for the second bonding layer, wherein the mass proportion of the triethoxysilane group in the silane-grafted ethylene-butene copolymer is 5wt%; the mixed raw material of the first bonding layer, the mixed raw material of the anti-creep layer and the mixed raw material of the second bonding layer are co-extruded to obtain a packaging film, which consists of a first bonding layer 1, an anti-creep layer 2 and a second bonding layer 3, the thickness of the first bonding layer 1 is 100μm, the thickness of the anti-creep layer 2 is 300μm, and the thickness of the second bonding layer 3 is 100μm.

[0068] Embodiment 13

[0069] The difference from Example 1 is that, by mass percentage, 50wt% of silane-grafted ethylene-butene copolymer and 50wt% of ethylene-octane copolymer are mixed to obtain a mixed raw material for the first bonding layer, wherein the mass proportion of triethoxysilane groups in the silane-grafted ethylene-butene copolymer is 5wt%; 50wt% of carboxyl and amino-modified ethylene-butene copolymer and 50wt% of ethylene-vinyl acetate copolymer are mixed to obtain a mixed raw material for the anti-creep layer, wherein the mass proportion of carboxyl groups in the carboxyl and amino-modified ethylene-butene copolymer is 4wt%, and the mass proportion of amino groups in the carboxyl and amino-modified ethylene-butene copolymer is 10wt%. The mass proportion of the base is 1wt%; 50wt% of the silane-grafted ethylene-butene copolymer is mixed with 50wt% of the ethylene-octane copolymer to obtain a mixed raw material for the second bonding layer, wherein the mass proportion of the triethoxysilane group in the silane-grafted ethylene-butene copolymer is 5wt%; the mixed raw material of the first bonding layer, the mixed raw material of the anti-creep layer and the mixed raw material of the second bonding layer are co-extruded to obtain a packaging film, which consists of a first bonding layer 1, an anti-creep layer 2 and a second bonding layer 3, the thickness of the first bonding layer 1 is 100μm, the thickness of the anti-creep layer 2 is 300μm, and the thickness of the second bonding layer 3 is 100μm.

[0070] Comparative Example 1

[0071] The difference from Example 1 is that the mixed raw materials of the anti-creep layer are the same as the mixed raw materials of the first bonding layer, and finally a packaging film is obtained.

[0072] Performance Testing

[0073] 1. Crosslinking degree of encapsulation film

[0074] The test method refers to the standard GB / T29848 "Ethylene-vinyl acetate copolymer (EVA) film for photovoltaic module encapsulation".

[0075] 2. Test the adhesion between packaging film and glass

[0076] The test method refers to GB / T29848 "Ethylene-vinyl acetate copolymer (EVA) film for photovoltaic module encapsulation".

[0077] 3. Creep resistance test

[0078] Take two float glasses with the size of 300mm*300mm*2mm (length*width*thickness) and a piece of packaging film 7 with the size of 300mm*270mm, and stack them in the order of first glass 6 / packaging film 7 / second glass 8, where the overlapping area of ​​the first glass 6 and the second glass 8 is the same as the size of the packaging film 7. Then fix the hook 4 on the surface of the first glass 6 with the structural adhesive 5, and after the structural adhesive 5 is completely cured, the following is obtained. Figure 2The test sample shown was hung in an oven at 105° C. for 15 days, and the distance the second glass 8 slid down was recorded.

[0079] The encapsulation films prepared in the examples and comparative examples were subjected to a crosslinking degree test, an encapsulation film-glass adhesion test, and a creep resistance test. The test results are shown in Table 1.

[0080] Table 1

[0081]

[0082]

[0083] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0084] The first adhesive layer and the second adhesive layer are used to ensure that the encapsulation film has good adhesion to the glass, thereby improving the reliability of the photovoltaic module, thereby reducing the probability of reliability problems such as bubbles and delamination in the photovoltaic module. The first functional group and the second functional group in the anti-creep layer undergo a cross-linking reaction during the encapsulation process of the encapsulation film, thereby improving the cross-linking degree of the encapsulation film, thereby improving the anti-creep effect of the encapsulation film. It is preferred to control the first functional group and the second functional group to be able to undergo a cross-linking reaction at the above temperature, which helps to promote the cross-linking reaction of the encapsulation film during the low-temperature encapsulation process. In addition, since the cross-linking of the encapsulation film is achieved by the cross-linking reaction between the first functional group and the second functional group on the modified resin, the anti-creep layer of the present application is free of peroxides and other small molecule additives, thereby helping to avoid the influence of peroxides and other small molecule additives on the batteries in the photovoltaic module. Therefore, the encapsulation film of the present application can achieve low-temperature encapsulation, and there is no small molecule additive residue in the encapsulation film, thereby improving the stability of the photovoltaic module.

[0085] The above are only embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A packaging film, characterized in that: The packaging adhesive film comprises a first adhesive layer (1), an anti-creep layer (2) and a second adhesive layer (3) stacked in sequence; in terms of mass percentage, The anti-creep layer (2) comprises 0-80 wt% of a first matrix resin and 20-100 wt% of a functional group modified resin; The first adhesive layer (1) and the second adhesive layer (3) each independently comprise 0 to 80 wt % of a second base resin and 20 to 100 wt % of a silane group-modified resin; The functional group in the functional group-modified resin includes a first functional group and a second functional group; The first functional group and the second functional group can undergo a cross-linking reaction at 100-120°C.

2. The packaging film according to claim 1, characterized in that: The mass proportion of the first functional group in the functional group modified resin is 0.5 to 5 wt%; and / or the mass proportion of the second functional group in the functional group modified resin is 0.5 to 5 wt%; Preferably, the mass ratio of the first functional group to the second functional group is 1:10 to 10:1; Preferably, the first functional group and the second functional group are independently selected from any one of hydroxyl, carboxyl, amino, epoxy, sulfonic acid, amide, cyano, isocyanate, acyl chloride, thiol and anhydride, and the first functional group can react with the second functional group.

3. The packaging film according to claim 1 or 2, characterized in that: The thickness of the first adhesive layer (1) and the second adhesive layer (3) are independently 50 to 200 μm; and / or the thickness of the anti-creep layer (2) is 100 to 500 μm; preferably, the ratio of the thickness of the first adhesive layer (1), the anti-creep layer (2) and the second adhesive layer (3) is 50 to 150:100 to 300:50 to 150.

4. The encapsulation film according to any one of claims 1 to 3, characterized in that: The mass ratio of the first base resin to the functional group modified resin is 60-80:20-40.

5. The encapsulation film according to any one of claims 1 to 4, characterized in that: The mass percentage of the silane group in the silane group modified resin is 0.5wt% to 10wt%; preferably, the structural formula of the silane group is Wherein, R is selected from any one of C1-C6 alkyl groups, and X and Y are each independently selected from any one of hydrogen, C1-C6 alkyl groups and C1-C6 alkoxy groups.

6. The packaging film according to any one of claims 1 to 5, characterized in that: The mass ratio of the second base resin to the silane group modified resin is 60-80:20-40.

7. The encapsulation film according to any one of claims 1 to 6, characterized in that: The peak melting point of the first matrix resin is 45-115° C.; and / or the first matrix resin is selected from a matrix resin with a density of 0.85-0.97 g / cm 3 Any one or more of polyethylene, ethylene and vinyl acetate copolymer, ethylene and α-olefin copolymer, ethylene and acrylic acid copolymer, ethylene and methyl acrylate copolymer, ethylene and ethyl acrylate copolymer, ethylene and methacrylic acid copolymer, and ethylene and methyl methacrylate copolymer; and / or, the peak melting point of the functional group modified resin is 40 to 115° C. and / or, the resin in the functional group modified resin is selected from a resin having a density of 0.85 to 0.97 g / cm 3 Any one or more of polyethylene, ethylene and vinyl acetate copolymer, ethylene and α-olefin copolymer, ethylene and acrylic acid copolymer, ethylene and methyl acrylate copolymer, ethylene and ethyl acrylate copolymer, ethylene and methacrylic acid copolymer, and ethylene and methyl methacrylate copolymer.

8. The packaging film according to any one of claims 1 to 7, characterized in that: The peak melting point of the second matrix resin is 45-115° C.; and / or, the second matrix resin is selected from any one or more of ethylene acetate and vinyl ester copolymers, ethylene and propylene copolymers, ethylene and butene copolymers, ethylene and pentene copolymers, ethylene and hexene copolymers, and ethylene and octene copolymers; And / or, the peak melting point of the silane group modified resin is 40-115° C.; and / or, the resin in the silane group modified resin is selected from any one or more of ethylene acetate and vinyl ester copolymers, ethylene and propylene copolymers, ethylene and butene copolymers, ethylene and pentene copolymers, ethylene and hexene copolymers, and ethylene and octene copolymers.

9. A photovoltaic module, characterized in that: The photovoltaic module contains at least one layer of cross-linked encapsulation film, and the cross-linked encapsulation film is formed by encapsulating the encapsulation film according to any one of claims 1 to 8.

10. The photovoltaic module according to claim 9, characterized in that: The cross-linking degree of the cross-linked packaging film is greater than 20 wt %.

Images