Damp-heat-resistant composition, photovoltaic packaging adhesive film and photovoltaic module

Abstract

The invention provides a damp-heat-resistant composition, a photovoltaic packaging adhesive film and a photovoltaic module, the damp-heat-resistant composition comprises polyolefin resin, a hybrid oligomer and a peroxide cross-linking agent, the hybrid oligomer is composed of an organic component, a functional group and metal ions, the metal ions are connected with the organic component through the functional group, and the peroxide cross-linking agent is connected with the organic component through the functional group. The hybrid oligomer comprises one or more of an acrylate group, a methacrylate group and an isocyanate group, and the metal ions are selected from one of zinc ions, aluminum ions, calcium ions or magnesium ions. The photovoltaic packaging adhesive film prepared from the damp-heat-resistant composition contains metal ion cross-linking bonds after being cross-linked, and has high binding power in a high-temperature and high-humidity state, so that a photovoltaic module adopting the photovoltaic packaging adhesive film keeps high PID resistance after an aging test.

Description

Technical Field

[0001] The present invention relates to the technical field of compositions, photovoltaic encapsulation films and photovoltaic modules, and in particular to a moisture- and heat-resistant composition, a photovoltaic encapsulation film made from the moisture- and heat-resistant composition and a photovoltaic module using the photovoltaic encapsulation film. Background Art

[0002] N-type TOPcon cells use silver-aluminum paste on the front, creating a large potential difference between silver and aluminum, which can easily form a galvanic cell. Water vapor intrusion, especially in high-temperature and high-humidity environments, can easily create a complex electrolyte environment, causing electrochemical corrosion and impacting module power. Existing technology can prevent water vapor intrusion by using an aluminum backsheet on the back, which has a near-zero water vapor transmission rate. However, aluminum backsheets are expensive and present bonding issues, making them less than ideal. Alternatively, the silver paste can be improved by eliminating aluminum-containing silver paste on the front, but current metallization welding processes have yet to achieve breakthroughs. Even if cell metallization technology is improved in the future, the peel strength between the encapsulation material and the glass and the module PID attenuation after high-temperature and high-humidity testing (DH1000h\2000h) will remain key technical indicators, directly impacting module performance. Summary of the Invention

[0003] The present invention provides a moisture-resistant heat-resistant composition, a photovoltaic encapsulation film, and a photovoltaic module, which are suitable for N-type TOPcon battery modules and solve the problem of reduced peeling force between photovoltaic encapsulation materials and glass in high-temperature and high-humidity environments, resulting in water vapor intrusion and power attenuation of photovoltaic modules.

[0004] In a first aspect, the present invention provides an anti-heat and moisture composition, which adopts the following technical scheme: it includes a polyolefin resin, a hybrid oligomer and a peroxide crosslinker, the hybrid oligomer is polymerized by an organic component, a metal ion and a functional group connecting the organic component and the organic component, the hybrid oligomer contains one or more of an acrylate group, a methacrylate group, an isocyanate group, a carboxyl group, a hydroxyl group, and a carbamate group, and the metal ion is selected from one of a zinc ion, an aluminum ion, a calcium ion or a magnesium ion.

[0005] Furthermore, the functional group is selected from one or more of acrylate group, methacrylate group and carbamate group.

[0006] Furthermore, the organic component is polyurethane or polyester.

[0007] Furthermore, the weight of the hybrid oligomer accounts for 0.1% to 1% of the weight of the polyolefin resin.

[0008] Furthermore, the polyolefin resin is a copolymer of ethylene and α-olefin or a copolymer of ethylene and a polar monomer.

[0009] Furthermore, the α-olefin is butene or octene, and the polar monomer is vinyl acetate.

[0010] Furthermore, it also includes functional additives, which are selected from one or more of cross-linking agents, coupling agents, and anti-aging agents.

[0011] In a second aspect, the present invention provides a photovoltaic encapsulation film, which adopts the following technical scheme: it includes any one of the above-mentioned anti-heat and moisture compositions, specifically, a polyolefin resin, a hybrid oligomer and a peroxide crosslinker, the hybrid oligomer is polymerized by an organic component, a metal ion and a functional group connecting the organic component and the organic component, the hybrid oligomer contains one or more of an acrylate group, a methacrylate group, an isocyanate group, a carboxyl group, a hydroxyl group, and a carbamate group, and the metal ion is selected from one of zinc ions, aluminum ions, calcium ions or magnesium ions.

[0012] Furthermore, the functional group is selected from one or more of acrylate group, methacrylate group and carbamate group.

[0013] Furthermore, the organic component is polyurethane or polyester.

[0014] Furthermore, the weight of the hybrid oligomer accounts for 0.1% to 1% of the weight of the polyolefin resin.

[0015] Furthermore, the polyolefin resin is a copolymer of ethylene and α-olefin or a copolymer of ethylene and a polar monomer.

[0016] Furthermore, the α-olefin is butene or octene, and the polar monomer is vinyl acetate.

[0017] Furthermore, it also includes functional additives, which are selected from one or more of cross-linking agents, coupling agents, and anti-aging agents.

[0018] Furthermore, the photovoltaic encapsulation film contains metal ion cross-linking bonds after the cross-linking reaction.

[0019] In a third aspect, the present invention provides a photovoltaic module, which adopts the following technical solution: comprising any one of the above-mentioned photovoltaic encapsulation films and an N-type TOPcon cell.

[0020] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The heat-resistant composition comprises a hybrid oligomer containing one or more of acrylate, methacrylate, isocyanate, carboxyl, hydroxyl, and urethane groups. These groups help improve the compatibility of the hybrid oligomer with the polyolefin resin and, under appropriate conditions, can react to crosslink the photovoltaic encapsulation film produced using the heat-resistant composition. Specifically, the isocyanate, carboxyl, and hydroxyl groups contribute to the further expansion of molecular segments in the hybrid oligomer.

[0022] 2. The hybrid oligomer is composed of an organic component, a functional group, and a metal ion. The metal ion is connected to the organic component via the functional group. The organic component is polyurethane or polyester. Photovoltaic encapsulation films made with a hybrid oligomer composition containing polyurethane as the organic component exhibit improved adhesion in high-temperature and high-humidity environments. Photovoltaic encapsulation films made with a hybrid oligomer composition containing polyester as the organic component also exhibit improved water-blocking properties in high-temperature and high-humidity environments.

[0023] 3. The photovoltaic encapsulation film made of the anti-heat and moisture composition, after cross-linking, the metal ions in the hybrid oligomer form metal ion cross-linking bonds in the photovoltaic encapsulation film. The metal ion cross-linking bonds can improve the adhesion of the photovoltaic encapsulation film to solar cells, glass, etc., especially the adhesion under high temperature and high humidity conditions is maintained or even improved, making it difficult for the photovoltaic encapsulation film to delaminate from the glass and solar cells.

[0024] 4. The photovoltaic modules using the above-mentioned photovoltaic encapsulation film have high adhesion with solar cells, glass, etc. under high temperature and high humidity conditions, which can prevent water vapor from invading from the interface between the photovoltaic encapsulation film and solar cells, glass, etc., thereby improving the moisture and heat resistance of the photovoltaic modules and reducing the power attenuation caused by water vapor intrusion, i.e., the anti-PID effect. DETAILED DESCRIPTION

[0025] The detailed description of the present invention and its embodiments are set forth one by one in the following detailed description in a non-limiting manner; however, the described parts are merely embodiments of the present invention and have no direct impact on the scope of the present invention. Therefore, the following description should not be interpreted in a limiting manner.

[0026] The present invention provides an anti-heat and humidity composition, comprising a polyolefin resin, a hybrid oligomer and a peroxide crosslinking agent. The hybrid oligomer is polymerized by an organic component, a metal ion and a functional group connecting the organic component to the organic component. The metal ion is connected to the organic component via the functional group. The hybrid oligomer contains one or more of an acrylate group, a methacrylate group, an isocyanate group, a carboxyl group, a hydroxyl group and a carbamate group. The metal ion is selected from one of a zinc ion, an aluminum ion, a calcium ion or a magnesium ion.

[0027] Using the above technical solution, acrylate, methacrylate, isocyanate, carboxyl, hydroxyl, or urethane groups help improve the compatibility of the hybrid oligomer with the polyolefin resin, thereby making the hybrid oligomer more evenly dispersed in the polyolefin resin and preventing random migration, making the overall moisture-heat resistant composition more stable and improving the storage stability of the moisture-heat resistant composition. Among them, the isocyanate, carboxyl, and hydroxyl groups help the hybrid oligomer continue to expand the molecular chain segments.

[0028] The addition of the peroxide crosslinking agent helps the photovoltaic encapsulation film made of the anti-heat and moisture composition to crosslink, forming metal ion crosslinking bonds and covalent bonds, thereby improving the stability of the photovoltaic encapsulation film.

[0029] Specifically, the functional group is selected from one or more of acrylate, methacrylate, and carbamate groups. The organic component is polyurethane or polyester.

[0030] Using this technical solution, acrylate, methacrylate, or carbamate groups are formed through reaction, tightly bonding with metal ions and organic components, ensuring stable chemical and physical properties of the hybrid oligomer. Acrylate and methacrylate groups can bond to metal ions or polyesters, while carbamate groups can bond to polyurethanes.

[0031] In some embodiments, the weight of the hybrid oligomer is 0.1% to 1% by weight of the polyolefin resin.

[0032] The above technical solution is adopted because even though the hybrid oligomer contains groups with good compatibility with polyolefins, the amount is limited. Adding too much will still risk precipitation, thus affecting the processing performance of the moisture-heat resistant composition. A photovoltaic encapsulation film made with the moisture-heat resistant composition using a hybrid oligomer content of 0.1% by weight relative to the weight of the polyolefin resin demonstrates the modified effect. Lower content levels result in no difference from conventional encapsulation films without the hybrid oligomer.

[0033] In some embodiments, the polyolefin resin is a copolymer of ethylene and an α-olefin or a copolymer of ethylene and a polar monomer. Preferably, the α-olefin is butene or octene. Preferably, the polar monomer is vinyl acetate.

[0034] In some embodiments, the anti-heat and humidity composition further comprises a functional auxiliary agent, and the functional auxiliary agent is selected from one or more of a cross-linking agent, a coupling agent, and an anti-aging agent.

[0035] By adopting the above technical solution, the product made by the anti-heat and moisture composition can be modified, for example: the coupling agent can give the product adhesion, the peroxide cross-linking agent can give the product processability, and the anti-aging agent can give the product anti-aging properties.

[0036] The present invention also provides a photovoltaic encapsulation film comprising any of the aforementioned heat-resistant compositions, specifically a polyolefin resin, a hybrid oligomer, and a peroxide crosslinker. The hybrid oligomer is polymerized from an organic component, a metal ion, and a functional group connecting the organic component to the organic component. The hybrid oligomer contains one or more of acrylate, methacrylate, isocyanate, carboxyl, hydroxyl, and carbamate groups, and the metal ion is selected from one of zinc, aluminum, calcium, and magnesium ions. Preferably, the functional group is selected from one or more of acrylate, methacrylate, and carbamate groups. Preferably, the organic component is polyurethane or polyester.

[0037] In some embodiments, the weight of the hybrid oligomer is 0.1% to 1% by weight of the polyolefin resin.

[0038] In some embodiments, the composition further comprises one or more of a peroxide cross-linking agent, a coupling agent, and an anti-aging agent.

[0039] In some embodiments, the polyolefin resin is a copolymer of ethylene and an α-olefin or a copolymer of ethylene and a polar monomer. Preferably, the α-olefin is butene or octene. Preferably, the polar monomer is vinyl acetate.

[0040] By adopting the above technical solution, the hybrid oligomer generates metal ion cross-linking bonds and covalent bonds in the photovoltaic encapsulation film. The metal ion cross-linking bonds can further improve the adhesion of the photovoltaic encapsulation film to the battery cells, glass, etc., especially the adhesion under high temperature and high humidity conditions is maintained or even improved, making it difficult for the photovoltaic encapsulation film to delaminate from the glass and battery cells.

[0041] Photovoltaic encapsulation films made from hybrid oligomers with polyurethane as the organic component exhibit better adhesion in high-temperature and high-humidity environments. Photovoltaic encapsulation films made from hybrid oligomers with polyester as the organic component exhibit better water-blocking properties in high-temperature and high-humidity environments.

[0042] The present invention also provides a photovoltaic module, comprising any one of the above-mentioned photovoltaic encapsulation films and an N-type TOPcon cell.

[0043] By adopting the above technical solution, the high adhesion between the photovoltaic encapsulation film and the battery cells, glass, etc. under high temperature and high humidity conditions can prevent water vapor from invading from the interface between the photovoltaic encapsulation film and the battery cells, glass, etc., thereby improving the moisture and heat resistance of the photovoltaic module and reducing the power attenuation caused by water vapor intrusion, that is, the anti-PID effect.

[0044] Example

[0045] Examples 1 to 14

[0046] Provided are photovoltaic encapsulation films, each having a single-layer structure and made from a moisture-resistant heat-resistant composition. The moisture-resistant heat-resistant composition comprises a polyolefin resin, a peroxide crosslinking agent, a hybrid oligomer, a co-crosslinking agent, a coupling agent, and a light stabilizer. The polyolefin resin comprises 100 parts by weight; the peroxide crosslinking agent comprises tert-butyl peroxy-2-ethylhexyl carbonate, comprising 0.5 parts by weight; the co-crosslinking agent comprises triallyl isocyanurate, comprising 0.6 parts by weight; the coupling agent comprises vinyltrimethoxysilane, comprising 0.3 parts by weight; and the light stabilizer comprises bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, comprising 0.3 parts by weight. The specific components of the polyolefin resin and the hybrid oligomer, as well as their specific components and weights, are shown in Table 1.

[0047] Table 1 Specific components of polyolefin resin, specific components of hybrid oligomer and weight parts

[0048]

[0049]

[0050] Comparative Example 1

[0051] A photovoltaic encapsulation film is provided, which differs from Example 3 in that no hybrid oligomer is added.

[0052] Comparative Example 2

[0053] A photovoltaic encapsulation film is provided, which differs from Example 13 in that no hybrid oligomer is added.

[0054] Performance testing

[0055] The photovoltaic encapsulation films provided in the above examples and comparative examples were tested for performance using the following method, and the test results are recorded in Table 2.

[0056] 1. DH peel strength after aging: a) Prepare two pieces of uncured photovoltaic encapsulation film, one piece of glass, and one piece of flexible backsheet, all of which are 300mm x 150mm in size; b) Stack the glass / two pieces of photovoltaic encapsulation film / flexible backsheet in that order, place them in a vacuum laminator, and cure and crosslink them according to the product's required curing temperature and time. After lamination and curing, there should be no bubbles in the photovoltaic encapsulation film. Prepare six specimens; c) Place all specimens in a high-temperature, high-humidity aging test chamber. Test conditions: temperature 85°C ± 2°C, relative humidity 85% ± 5%; D) Test time for three of the samples: 1000 h; test time for the other three samples: 2000 h; E) After the test, remove the samples and allow them to recover in an open environment at 23°C ± 5°C and a relative humidity of less than 75% for 2 to 4 hours. Then, perform a visual inspection to ensure that there are no visual defects; F) Cut the flexible backsheet / photovoltaic encapsulation film layer into samples with a width of 10 mm ± 0.5 mm at 5 mm intervals in the width direction for testing the peel force between the photovoltaic encapsulation film and the glass; G) Measure the peel force between the photovoltaic encapsulation film and the glass on a tensile testing machine at a tensile speed of 100 mm / min ± 10 mm / min according to the test method of GB / T 2790-1995. Peel strength = peel force / sample width, measured in N / cm.

[0057] Table 2 Peel strength of photovoltaic encapsulation film after DH1000h and DH2000h testing

[0058] Example Peel strength (DH1000h) Peel strength (DH2000h) Example 1 82 51 Example 2 94 62 Example 3 100 73 Example 4 91 60 Example 5 89 59 Example 6 90 61 Example 7 88 58 Example 8 91 59 Example 9 91 62 Example 10 89 60 Example 11 81 50 Example 12 83 55 Example 13 95 65 Example 14 81 56 Example 15 84 54 Comparative Example 1 60 38 Comparative Example 2 52 25

[0059] The test results show that the addition of hybrid oligomers can significantly improve the moisture and heat resistance of photovoltaic encapsulation films, ensuring the stability and durability of the adhesive properties of photovoltaic encapsulation films. The specific choice of hybrid oligomer has little effect on the adhesive properties of photovoltaic encapsulation films. Hybrid oligomers are highly compatible with polyolefins, and are particularly compatible with ethylene-butene, ethylene-octene, and ethylene-vinyl acetate. The peel strength after testing when added to ethylene-vinyl acetate is slightly lower than when added to ethylene-butene or ethylene-octene. This may be because ethylene-vinyl acetate itself has a higher water absorption rate than ethylene-butene or ethylene-octene, resulting in a faster decrease in peel strength after testing.

[0060] Examples 16 to 32

[0061] A photovoltaic module is provided, each comprising the photovoltaic encapsulation films provided in Examples 1 to 15, an N-type TOPcon cell, glass, and glass. To expedite the experimental process, the examples provided simple modules rather than commercially available complete modules.

[0062] Lay out in the order of glass / photovoltaic encapsulation film / N-type TOPcon cell array / photovoltaic encapsulation film / glass, and laminate using a conventional lamination process to obtain components S1 to S15 to be tested.

[0063] Comparative Example 3

[0064] The following order is followed: glass / film provided in comparative example 1 / N-type TOPcon cell array / film provided in comparative example 1 / glass. The components are laminated using a conventional lamination process to obtain a component to be tested S16.

[0065] Comparative Example 4

[0066] The following order is laid: glass / film provided in comparative example 2 / N-type TOPcon cell array / film provided in comparative example 2 / glass, and laminated using a conventional lamination process to obtain a test assembly S17.

[0067] Performance testing

[0068] The photovoltaic modules of the above embodiments and comparative examples were tested for performance using the following method, and the test results are recorded in Table 3.

[0069] 1. Potential Induced Degradation (PID) test: Place the PV module in an environmental chamber with a relative humidity of 85% and a temperature of 85°C for 1000 hours. Measure the power of the PV module before and after placement in the environmental chamber. Calculate the power change ratio and record its absolute value: power change ratio = (power after test - power before test) / power before test.

[0070] Table 3 Power change rate of photovoltaic modules

[0071] Components to be tested Power change rate Components to be tested Power change rate Components to be tested Power change rate S1 2.81％ S2 2.54％ S3 1.98％ S4 2.31％ S5 2.42％ S6 2.37％ S7 2.35％ S8 2.34％ S9 2.38％ S10 2.32％ S11 2.90％ S12 2.72％ S13 2.24％ S14 2.69％ S15 2.73％ S16 3.05％ S17 3.42％

[0072] The test results show that adding hybrid oligomers can enhance the PID resistance of photovoltaic modules, with the higher the added content, the better the anti-PID effect. The specific choice of hybrid oligomer has little impact on the anti-PID effect. The anti-PID effect of the polyolefin resin using ethylene-vinyl acetate copolymer is slightly lower, possibly because ethylene-vinyl acetate copolymer itself is less effective than ethylene-butene copolymer or ethylene-octene copolymer in anti-PID performance.

[0073] In this specification, the present invention has been described with reference to specific embodiments thereof. However, it will be apparent that various modifications and variations may be made without departing from the spirit and scope of the present invention. Therefore, the description is to be regarded as illustrative rather than restrictive.

Claims

1. A heat and humidity resistant composition, characterized in that: The invention comprises a polyolefin resin, a hybrid oligomer and a peroxide crosslinking agent. The hybrid oligomer is polymerized by an organic component, a metal ion and a functional group connecting the organic component and the organic component. The hybrid oligomer contains one or more of an acrylate group, a methacrylate group, an isocyanate group, a carboxyl group, a hydroxyl group and a carbamate group. The metal ion is selected from one of zinc ion, aluminum ion, calcium ion or magnesium ion.

2. The heat-resistant composition according to claim 1, wherein: The functional group is selected from one or more of acrylate group, methacrylate group and carbamate group.

3. The heat-resistant composition according to claim 1 or 2, characterized in that: The organic component is polyurethane or polyester.

4. The heat-resistant composition according to claim 1, wherein: The weight of the hybrid oligomer accounts for 0.1% to 1% of the weight of the polyolefin resin.

5. The heat-resistant composition according to claim 1, wherein: The polyolefin resin is a copolymer of ethylene and α-olefin or a copolymer of ethylene and a polar monomer.

6. The heat-resistant composition according to claim 5, characterized in that: The α-olefin is butene or octene, and the polar monomer is vinyl acetate.

7. The heat-resistant composition according to claim 1, characterized in that: It also includes functional additives, which are selected from one or more of a cross-linking agent, a coupling agent, and an anti-aging agent.

8. A photovoltaic encapsulation film, characterized in that: The invention comprises an anti-heat and humidity composition according to any one of claims 1 to 7.

9. The photovoltaic encapsulation film according to claim 9, characterized in that: After the cross-linking reaction, it contains metal ion cross-linking bonds.

10. A photovoltaic module, characterized in that: It comprises the photovoltaic encapsulation film as described in claim 8 and an N-type TOPcon battery.

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