Low modulus encapsulant film for perovskite module and perovskite module

Abstract

The application provides a low-modulus encapsulating adhesive film for a perovskite assembly and the perovskite assembly. The low-modulus encapsulating adhesive film for the perovskite assembly comprises a low-modulus layer, the low-modulus layer is arranged towards a perovskite battery layer by layer, and the elastic modulus of the low-modulus layer is lower than 16 MPa at 40 DEG C; the elastic modulus of the low-modulus layer is tested by DMA, the sample of the low-modulus layer is cut into a 6 mm wide sample strip, a temperature scanning mode is adopted, and the elastic modulus of the low-modulus layer is tested at an oscillation frequency of 1 Hz within a range of 30 DEG C to 90 DEG C. The low-modulus encapsulating adhesive film for the perovskite assembly of the application comprises a low-modulus layer, the modulus of the low-modulus encapsulating adhesive film for the perovskite assembly as a whole is reduced by controlling the elastic modulus of the low-modulus layer to be lower than 16 MPa at 40 DEG C, the interface stress between the low-modulus encapsulating adhesive film for the perovskite assembly and the perovskite battery in cold and hot cycles is reduced, the problem of interlayer peeling of the perovskite battery is avoided, and the reliability of the perovskite assembly is improved.

Description

Technical Field

[0001] This invention relates to the field of perovskite module technology, and more specifically, to a low-modulus encapsulating film for perovskite modules and a perovskite module. Background Technology

[0002] With energy shortages and environmental problems becoming increasingly prominent, the search for renewable and environmentally friendly green energy has become an inevitable trend. Photovoltaic power generation is the process of converting solar energy into electrical energy. It has three major advantages: permanence, cleanliness, and flexibility. Moreover, compared with traditional thermal power generation, hydropower generation, and nuclear power generation, its preparation process is simple and highly replicable, thus showing great development prospects.

[0003] In recent years, photovoltaic cell technology has developed rapidly. In the crystalline silicon field, new high-efficiency cells such as HJT and Topcon have achieved conversion efficiencies of over 26%, approaching the theoretical limit of crystalline silicon cells, making it increasingly difficult to improve efficiency. Perovskite cells, with their low cost and high theoretical conversion rate, are considered a new direction for the future development of photovoltaic modules. With continuous breakthroughs in perovskite cell technology in recent years, the stability of perovskite modules has been continuously improved, and the industrialization of perovskite modules has been gradually realized. Currently, perovskite modules mainly include single-junction modules and tandem modules. Single-junction modules contain only one type of perovskite cell, comprising a front panel material 1, a perovskite cell 2, an encapsulating film 3, and a back panel material 4 stacked sequentially, as shown in the diagram. Figure 1 As shown, the front panel material 1 and the rear panel material 4 can be glass or other flexible water-blocking materials. The tandem solar cell includes front panel material 1, perovskite cell 2, crystalline silicon cell 5, rear panel material 4, front encapsulation film 6, and rear encapsulation film 7, mainly comprising two structures, see... Figure 2 and Figure 3 In Structure 1, the perovskite cell 2 is located on the inner side of the front panel material 1, separated from the crystalline silicon cell 5, and a pre-encapsulation film 6 is required between them. In Structure 2, the perovskite cell is located on the surface of the crystalline silicon cell, and the pre-encapsulation film 6 is located between the perovskite cell 2 and the front panel material 1.

[0004] Perovskite solar cells have a multilayer structure and low interlayer adhesion. The encapsulating film is mostly made of polymer materials with a high coefficient of thermal expansion. During high and low temperature cycling tests, the difference in thermal expansion coefficients between the perovskite cell and the encapsulating material causes stress at the interface, leading to interlayer delamination and ultimately cell failure. Therefore, a new low-modulus encapsulating film is needed to reduce the stress at the interface between the encapsulating film and the perovskite cell caused by thermal expansion and contraction, thus solving the problem of interlayer delamination in perovskite solar cells. Summary of the Invention

[0005] The main objective of this invention is to provide a low-modulus encapsulating film for perovskite modules and a perovskite module, so as to solve the problem of interlayer delamination of perovskite cells caused by stress at the interface between the encapsulating film and the perovskite cell in the prior art.

[0006] To achieve the above objectives, according to one aspect of the present invention, a low-modulus encapsulating film for perovskite modules is provided, comprising a low-modulus layer, the low-modulus layer being stacked toward the perovskite cell, the low-modulus layer having an elastic modulus of less than 16 MPa at 40°C; the elastic modulus of the low-modulus layer is tested using DMA, by cutting a sample of the low-modulus layer into 6 mm wide strips, and using a temperature scanning mode to test the elastic modulus of the low-modulus layer in the range of 30°C to 90°C at an oscillation frequency of 1 Hz.

[0007] Furthermore, the low-modulus layer has an elastic modulus of 0.1~3MPa at 80℃.

[0008] Furthermore, the thickness of the low-modulus layer is not less than 0.2 mm, and preferably the thickness of the low-modulus layer is 0.2 mm to 0.6 mm.

[0009] Furthermore, the low-modulus encapsulating film for perovskite modules is a cross-linked film. By weight, the low-modulus encapsulating film for perovskite modules comprises: 100 parts of matrix resin, 5-50 parts of low-modulus additive, 0.1-2 parts of cross-linking agent, 0.1-2 parts of co-cross-linking agent, 0.1-2 parts of silane coupling agent, and 0-2 parts of light stabilizer; wherein, the elastic modulus of the low-modulus additive is ≤16MPa at 40℃ and 0.1-3MPa at 80℃.

[0010] Furthermore, the low-modulus encapsulating film for perovskite modules is a non-crosslinked film. By weight, the low-modulus encapsulating film for perovskite modules comprises: 0-60 parts of matrix resin, 40-100 parts of tackifying and modifying resin, and 5-50 parts of low-modulus additive; wherein the total amount of matrix resin and tackifying and modifying resin is 100 parts; and / or, the low-modulus additive has an elastic modulus ≤16MPa at 40℃ and an elastic modulus of 0.1-3MPa at 80℃; the tackifying and modifying resin is selected from any one or more of silane-modified POE.

[0011] Furthermore, the viscosity of the low-modulus additive is not higher than 50,000 Pa·s, and preferably the viscosity of the low-modulus additive is 5,000~30,000 Pa·s.

[0012] Furthermore, the low-modulus additive is selected from any one or more of liquid polyurethane rubber, liquid polybutadiene rubber, liquid polyisoprene rubber, liquid styrene-butadiene rubber, liquid pentadiene rubber, acrylic liquid rubber, polyamide liquid rubber, polyether polyol, polyester polyol, and liquid silicone rubber.

[0013] Furthermore, the low-modulus encapsulating film for perovskite modules is a single-layer film or a multi-layer film.

[0014] According to another aspect of the present invention, a perovskite module is provided, comprising a low-modulus encapsulating film and a perovskite cell, wherein the low-modulus layer of the low-modulus encapsulating film is stacked toward the perovskite cell, and the low-modulus encapsulating film is the aforementioned low-modulus encapsulating film for perovskite modules.

[0015] Furthermore, the perovskite module is a single-junction perovskite module or a perovskite-crystalline silicon tandem module; the coefficient of thermal expansion of the low-modulus encapsulating film is 120~280ppm / K. When the perovskite module is a single-junction perovskite module, the low-modulus encapsulating film also includes fillers, preferably selected from any one or more of ceramics, glass, silicon carbide, mullite, alumina, rutile, and graphite.

[0016] By applying the technical solution of this invention, the low-modulus encapsulating film for perovskite modules of this application includes a low-modulus layer. By controlling the elastic modulus of the low-modulus layer at 40°C to be lower than 16 MPa, the overall modulus of the low-modulus encapsulating film for perovskite modules is reduced, thereby reducing the interfacial stress between the low-modulus encapsulating film for perovskite modules and the perovskite cell during thermal cycling, thus avoiding the problem of interlayer delamination of the perovskite cell and improving the reliability of the perovskite module. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0018] Figure 1 A schematic diagram of the structure of a single-junction perovskite assembly in the prior art is shown;

[0019] Figure 2 A schematic diagram of the structure of a stacked perovskite assembly in the prior art is shown;

[0020] Figure 3 A schematic diagram of another stacked perovskite assembly in the prior art is shown.

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

[0022] 1. Front panel material; 2. Perovskite solar cell; 3. Encapsulation film; 4. Back panel material; 5. Crystalline silicon solar cell; 6. Front encapsulation film; 7. Back encapsulation film. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] As analyzed in the background section of this application, the prior art has a problem of interlayer delamination of perovskite cells caused by stress at the interface between the encapsulation film and the perovskite cell. In order to solve the above problem, this application provides a low-modulus encapsulation film for perovskite modules and a perovskite module.

[0025] In a typical embodiment of this application, a low-modulus encapsulating film for perovskite modules is provided, including a low-modulus layer stacked towards the perovskite solar cell. The low-modulus layer has an elastic modulus of less than 16 MPa at 40°C. The elastic modulus of the low-modulus layer is tested using DMA. A sample of the low-modulus layer is cut into 6 mm wide strips, and the elastic modulus of the low-modulus layer is tested in a temperature scanning mode at an oscillation frequency of 1 Hz within the range of 30°C to 90°C.

[0026] The low-modulus encapsulating film for perovskite modules in this application includes a low-modulus layer. By controlling the elastic modulus of the low-modulus layer to be below 16 MPa at 40°C, the overall modulus of the low-modulus encapsulating film for perovskite modules is reduced, thereby reducing the interfacial stress between the low-modulus encapsulating film and the perovskite cell during thermal cycling, thus avoiding the problem of interlayer delamination of the perovskite cell and improving the reliability of the perovskite module.

[0027] In one embodiment of this application, the low-modulus layer has an elastic modulus of 0.1~3MPa at 80°C.

[0028] When the elastic modulus of the low-modulus layer is too high at 80℃, its buffering capacity is insufficient, making it difficult to effectively absorb thermal expansion stress. Conversely, if the elastic modulus of the low-modulus layer is too low, it can lead to uneven film flow due to excessive fluidity during the lamination process, resulting in residual bubbles or displacement of perovskite solar cells. Therefore, controlling the elastic modulus of the low-modulus layer at 80℃ within the range of 0.1~3MPa ensures that the film maintains high flexibility and viscoelasticity under high-temperature operating conditions. This helps to continuously absorb thermal expansion stress, prevents stress concentration due to material hardening, and thus inhibits delamination and crack propagation caused by long-term thermal stress accumulation.

[0029] In one embodiment of this application, the thickness of the low modulus layer is not less than 0.2 mm, and preferably the thickness of the low modulus layer is 0.2 mm to 0.6 mm.

[0030] To achieve effective interfacial stress buffering, this invention controls the thickness of the low-modulus layer within the range of 0.2 mm to 0.6 mm. A thickness ≥ 0.2 mm provides sufficient deformation space, allowing the film to effectively dissipate interfacial stress caused by thermal expansion mismatch through viscoelastic deformation during thermal cycling. A thickness ≤ 0.6 mm helps reduce the risk of poor heat conduction or encapsulation volume expansion due to excessive thickness, taking into account the compatibility between stress dispersion efficiency and encapsulation density.

[0031] In one embodiment of this application, the low-modulus encapsulating film for perovskite modules is a cross-linked film. By weight, the low-modulus encapsulating film for perovskite modules comprises: 100 parts of matrix resin, 5-50 parts of low-modulus additive, 0.1-2 parts of cross-linking agent, 0.1-2 parts of co-cross-linking agent, 0.1-2 parts of silane coupling agent, and 0-2 parts of light stabilizer; wherein, the low-modulus additive has an elastic modulus ≤16MPa at 40°C and an elastic modulus of 0.1-3MPa at 80°C.

[0032] In cross-linked films, the matrix resin forms a continuous cross-linked network structure, serving as the supporting framework of the film. Low-modulus additives are dispersed within it as a flexible phase. Cross-linking agents and co-cross-linking agents form a covalent cross-linked network, and silane coupling agents further enhance interfacial bonding. This formulation helps maintain the integrity of the cross-linked network structure, reduces the overall elastic modulus of the encapsulation film, thereby effectively relieving interfacial stress during thermal cycling and improving the durability of the encapsulation film.

[0033] In one embodiment of this application, the low-modulus encapsulating film for perovskite modules is a non-crosslinked film. By weight, the low-modulus encapsulating film for perovskite modules comprises: 0-60 parts of matrix resin, 40-100 parts of tackifying and modifying resin, and 5-50 parts of low-modulus additive; wherein the total amount of matrix resin and tackifying and modifying resin is 100 parts; and / or, the low-modulus additive has an elastic modulus ≤16MPa at 40°C and an elastic modulus of 0.1-3MPa at 80°C; the tackifying and modifying resin is selected from any one or more of silane-modified POE.

[0034] Non-crosslinked adhesive films use silane-modified POE as the main tackifying component. Because its silane end groups can bond with hydroxyl or oxygen on the perovskite surface to form chemical anchoring, strong adhesion can be achieved without thermal curing. At the same time, low-modulus additives, as highly flexible dispersed phases, provide internal stress buffering, enabling the adhesive film to achieve high adhesion and low modulus without crosslinking network, thereby simplifying the encapsulation process and reducing energy consumption.

[0035] In one embodiment of this application, the viscosity of the low-modulus additive is not higher than 50,000 Pa·s, and preferably the viscosity of the low-modulus additive is 5,000 to 30,000 Pa·s.

[0036] Controlling the viscosity of low-modulus additives within the range of 5000~30000 Pa·s helps them to disperse uniformly during melt blending, reducing the risk of localized modulus increases caused by high-viscosity agglomeration. If the viscosity of low-modulus additives is too low, the fluidity will be too strong, and the low-modulus additives will easily seep out or migrate during lamination, leading to contamination of the film interface or uneven thickness. If the viscosity of low-modulus additives is too high, the fluidity will be insufficient, and the low-modulus additives will be difficult to mix fully with the matrix resin. This viscosity range helps low-modulus additives form a continuous and uniform flexible phase in the film, thereby achieving the stability and uniformity of the overall elastic modulus of the film.

[0037] In one embodiment of this application, the low-modulus additive is selected from any one or more of liquid polyurethane rubber, liquid polybutadiene rubber, liquid polyisoprene rubber, liquid styrene-butadiene rubber, liquid pentadiene rubber, acrylic liquid rubber, polyamide liquid rubber, polyether polyol, polyester polyol, and liquid silicone rubber.

[0038] The preferred low-modulus additives are polymers with flexible main chains and polar groups. They have low coefficients of friction within the molecular chain, which helps to reduce the glass transition temperature and room temperature elastic modulus of the encapsulating film. At the same time, their polar groups form hydrogen bonds, dipole interactions, or coordination interactions with hydroxyl groups, oxygen vacancies, or halogen atoms on the surface of the perovskite layer, which helps to enhance the interfacial adhesion strength between the encapsulating film and the perovskite layer.

[0039] Crosslinking agents are molecules with multiple olefinic unsaturated groups that can promote polymer crosslinking and achieve a higher degree of crosslinking. The crosslinking agent in the above composition can be selected from commonly used types in the art, preferably selected from any one or more of the following: tert-butyl peroxycarbonate, 2,5-dimethyl-2,5-(bis-tert-butylperoxy)hexane, tert-butyl peroxycarbonate-2-ethylhexyl ester, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-pentylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-pentylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-pentyl peroxycarbonate, 2,5-dimethyl-2,5-bis(benzoylperoxy)-hexane, tert-pentyl peroxycarbonate, and tert-butyl peroxy3,3,5-trimethylhexanoate.

[0040] In some embodiments, the co-crosslinking agent includes tris(2-hydroxyethyl) isocyanurate triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propionyl oxylated pentaerythritol tetraacrylate, trimethylolpropane tetraacrylate, ethoxylated trimethylolpropane triacrylate, propionyl oxylated trimethylolpropane triacrylate, ethoxylated glycerol triacrylate, propionyl glycerol triacrylate, bis(trimethylolpropane tetraacrylate), 1,5(ethoxy)trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, bis(trimethylolpropane tetramethacrylate), tricyclodecanedimethylol diacrylate, and tricyclodecanedimethylol diacrylate. One or more of the following: propionic acid oxynepentyl glycol diacrylate, ethoxylated bisphenol A diacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, polyethylene glycol 200 diacrylate, polyethylene glycol 400 diacrylate, polyethylene glycol 600 diacrylate, ethoxylated bisphenol A dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol 200 dimethacrylate, polyethylene glycol 400 dimethacrylate, 1,6-hexanediol dimethacrylate, triallyl isocyanurate, triallyl cyanurate, and isobornyl methacrylate.

[0041] In some embodiments, the silane coupling agent includes γ-aminopropyltriethoxysilane (KH550), γ-aminopropyltrimethoxysilane (KH540), N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH792), diethylaminomethyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane (KH570), vinyltrimethoxysilane (A171), vinyltriethoxysilane (A151), and vinyltris(β-methoxyethoxy)silane (A172). Vinyltriacetoxysilane, allyltrimethoxysilane, allyltriethoxysilane, dimethoxymethylvinylsilane, diethoxymethylvinylsilane, p-styryltrimethoxysilane, p-styryltriethoxysilane, γ-mercaptopropyltrimethoxysilane (KH590), γ-mercaptopropyltriethoxysilane (KH580), vinyltriperoxide tert-butylsilane, γ-chloropropyltrimethoxysilane, γ-isocyanate propyltriethoxysilane, methyltrimethoxysilane, n-propyltrimethoxysilane, β-(3,4-ethoxycyclohexyl)ethyltrimethoxysilane, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate, or one or more of these.

[0042] In some embodiments, the light stabilizer includes bis-2,2,6,6-tetramethylpiperidinol sebacate (UV-770), bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate (light stabilizer 123), N,N'-bis-(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate (UV-292), a polymer of succinic acid and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol (UV-622), N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine, and Polymers of 2,4-dichloro-6-(4-morpholino)-1,3,5-triazine (UV-944), tris(1,2,2,6,6-pentamethyl-4-piperidinyl)phosphite (light stabilizer 765), poly[(6-morpholino-5-triazine-2,4-diyl)[(2,2,6,6-tetramethyl-4-piperidinyl)imino]-hexamethylene[(2,2,6,6-tetramethyl-4-piperidinyl)imino]] (light stabilizer 783), polymethylpropyl 3-oxo-(2,2,6,6-tetramethyl)piperidinylsiloxane (light stabilizer 2908), and one or more of 4-benzoyloxy-2,2,6,6-tetramethylpiperidine. The preferred light stabilizers help to further delay surface chalking, cracking and discoloration by capturing free radicals generated during photo-oxidation, decomposing hydrogen peroxide and achieving recycling; when used in combination with UV absorbers, the light stabilizers can chemically block the aging chain reaction, reduce the risk of yellowing and embrittlement of the film, and improve outdoor weather resistance.

[0043] In one embodiment of this application, the low-modulus encapsulating film for the perovskite module is a single-layer film or a multi-layer film.

[0044] Single-layer encapsulant film structures are simple to manufacture and suitable for standardized encapsulation processes. Multi-layer encapsulant film structures are preferred and can be designed as gradient interface structures consisting of a high-modulus outer layer and a low-modulus inner layer. The outer layer provides mechanical protection, while the inner layer absorbs the interface stress caused by thermal cycling and mechanical deformation, thereby improving the long-term reliability of the component.

[0045] In another typical embodiment of this application, a perovskite module is provided, including a low-modulus encapsulating film and a perovskite cell, wherein the low-modulus layer of the low-modulus encapsulating film is stacked toward the perovskite cell, and the low-modulus encapsulating film is the aforementioned low-modulus encapsulating film for perovskite modules.

[0046] The perovskite module of this application uses a low-modulus encapsulating film with a thermal expansion coefficient of 120~280ppm / K. This can reduce the interfacial stress between the encapsulating film and the perovskite layer during thermal cycling, reduce interlayer debonding and microcrack generation, thereby extending the module's service life and improving long-term operational reliability.

[0047] In one embodiment of this application, the perovskite module is a single-junction perovskite module or a perovskite-silicon tandem module; when the perovskite module is a single-junction perovskite module, the low-modulus encapsulation film further includes fillers, preferably selected from any one or more of ceramics, glass, silicon carbide, mullite, alumina, rutile, and graphite.

[0048] By introducing fillers with thermal expansion coefficients matching those of the perovskite layer into the single-junction module, the risk of thermal expansion mismatch between the perovskite layer and the encapsulating film is reduced, thereby reducing the overall thermal stress gradient of the module. The preferred fillers and the low-modulus encapsulating film form a composite structure of rigid skeleton and flexible buffer, which helps to suppress interface peeling and crack propagation caused by thermal cycling, and is especially beneficial to alleviating the problem of increased thermal stress concentration in large-size modules due to increased area.

[0049] The beneficial effects of this application will be further illustrated below with reference to the embodiments.

[0050] Example 1

[0051] The low-modulus encapsulating film is a cross-linked encapsulating film. By weight, the low-modulus encapsulating film for perovskite modules includes:

[0052] The composition comprises 100 parts of ethylene-vinyl acetate copolymer (EVA) as the base resin, 15 parts of low-modulus additive liquid polybutadiene rubber with a viscosity of 30000 Pa·s, 1 part of crosslinking agent tert-butylperoxycarbonate-2-ethylhexyl ester, 1 part of co-crosslinking agent trimethylolpropane tetraacrylate, 1 part of silane coupling agent γ-methacryloyloxypropyltrimethoxysilane, and 0.3 parts of light stabilizer bis-2,2,6,6-tetramethylpiperidinol sebate. These materials are mixed in the specified proportions and then extruded by casting to prepare a crosslinked low-modulus encapsulating film. The thickness of the low-modulus layer is 0.6 mm. The encapsulating film is a single-layer film consisting only of the aforementioned low-modulus layer; no fillers are added.

[0053] Example 2

[0054] The difference from Example 1 is that the thickness of the low modulus layer is 0.2 mm, and a cross-linked low modulus encapsulation film is finally obtained.

[0055] Example 3

[0056] The difference from Example 1 is that the thickness of the low modulus layer is 0.1 mm, and a cross-linked low modulus encapsulation film is finally obtained.

[0057] Example 4

[0058] The difference from Example 1 is that the amount of low modulus additive added is 5 parts, and a cross-linked low modulus encapsulation film is finally obtained.

[0059] Example 5

[0060] The difference from Example 1 is that the amount of low modulus additive added is 50 parts, and a cross-linked low modulus encapsulating film is finally obtained.

[0061] Example 6

[0062] The difference from Example 1 is that the amount of low modulus additive added is 60 parts, and a cross-linked low modulus encapsulation film is finally obtained.

[0063] Example 7

[0064] The difference from Example 1 is that the low modulus additive is a polyether polyol with a viscosity of 10000 Pa·s, and a cross-linked low modulus encapsulation film is finally obtained.

[0065] Example 8

[0066] The difference from Example 1 is that the low modulus additive is a 1:1 compound of liquid polyurethane rubber and liquid polybutadiene rubber; the viscosity is 20000 Pa·s, and a cross-linked low modulus encapsulation film is finally obtained.

[0067] Example 9

[0068] The difference from Example 1 is that the viscosity of the low-modulus additive liquid polybutadiene rubber is 5000 Pa·s, and a cross-linked low-modulus encapsulation film is finally obtained.

[0069] Example 10

[0070] The difference from Example 1 is that the viscosity of the low-modulus additive liquid polybutadiene rubber is 35000 Pa·s, and a cross-linked low-modulus encapsulation film is finally obtained.

[0071] Example 11

[0072] The difference from Example 1 is that 5 wt% alumina filler was added, resulting in a cross-linked low-modulus encapsulation film.

[0073] Example 12

[0074] Example 12 is a three-layer structure with ABA, wherein the proportion of the middle layer B is the same as in Example 1, and the thickness is 0.4 mm. The thickness of the two edge layers A is 0.1 mm, and the proportions are the same as in Example 1, except that the amount of low-modulus additive added is 0 parts. The two proportions of materials are co-extruded and cast to finally obtain a cross-linked low-modulus encapsulating film.

[0075] Example 13

[0076] Example 13 is a three-layer structure with ABA, wherein the ratio of the two edge layers A is the same as in Example 1, and the thickness is 0.2 mm. The ratio of the middle layer B is the same as in Example 1, except that the amount of low modulus additive added is 0 parts, and the thickness is 0.2 mm. The two ratios of materials are co-extruded and cast to finally obtain a cross-linked low modulus encapsulating film.

[0077] Example 14

[0078] The difference from Example 1 is that the encapsulating film is a non-crosslinked encapsulating film. By weight, the low-modulus encapsulating film for perovskite modules includes: 20 parts of matrix resin (ethylene-butene copolymer), 80 parts of tackifying and modifying resin (silane-grafted ethylene-butene copolymer), and 15 parts of low-modulus additive (liquid polyisoprene rubber) with a viscosity of 20000 Pa·s. After uniformly mixing the above components, the film is extruded by casting to finally obtain a non-crosslinked low-modulus encapsulating film with a thickness of 0.6 mm.

[0079] Example 15

[0080] The difference from Example 14 is that the base resin (ethylene-butene copolymer) is 0 parts and the tackifying resin (silane-grafted ethylene-butene copolymer) is 100 parts, resulting in a non-crosslinked low-modulus encapsulating film.

[0081] Example 16

[0082] The difference from Example 14 is that the base resin (ethylene-butene copolymer) is 60 parts and the tackifying and modifying resin (silane-grafted ethylene-butene copolymer) is 40 parts, resulting in a non-crosslinked low-modulus encapsulating film.

[0083] Example 17

[0084] The difference from Example 14 is that the base resin (ethylene-butene copolymer) is 70 parts and the tackifying and modifying resin (silane-grafted ethylene-butene copolymer) is 30 parts, resulting in a non-crosslinked low-modulus encapsulating film.

[0085] Example 18

[0086] The difference between Example 18 and Example 14 is that Example 18 is a three-layer structure with ABA, wherein the ratio of the middle layer B is the same as in Example 14, and the thickness is 0.4 mm. The thickness of the two edge layers A is 0.1 mm, and the ratio is different from that in Example 14, except that the amount of low modulus additive added is 0 parts. The two ratios of materials are co-extruded and cast to finally obtain a non-crosslinked low modulus encapsulating film.

[0087] Example 19

[0088] The difference between Example 19 and Example 14 is that Example 19 is a three-layer structure with ABA, wherein the ratio of the two edge layers is the same as that of Example 14, and the thickness is 0.2 mm. The ratio of the middle layer is different from that of Example 14, except that the amount of low modulus additive added is 0 parts, and the thickness is 0.2 mm. The materials with the two ratios are co-extruded and cast to finally obtain a non-crosslinked low modulus encapsulating film.

[0089] Comparative Example 1

[0090] The difference from Example 1 is that the low-modulus additive is conventional EVA resin, and the final product is an EVA encapsulation film.

[0091] Performance testing:

[0092] The films prepared in the above embodiments and comparative examples were subjected to the following performance tests, and the test results are listed in Table 1.

[0093] Elastic modulus: The elastic modulus of the low-modulus layer film was tested after lamination at 120℃ and 100kPa for 20 minutes. The elastic modulus test was performed using DMA (Digital Modulus Analysis). The laminated sample was cut into 6mm wide strips, and the elastic modulus of the low-modulus layer was measured at an oscillation frequency of 1Hz within the temperature range of 30℃ to 90℃.

[0094] Adhesion to glass: The low-modulus layer of the adhesive film was laminated at 120℃ and 100kPa for 20 minutes, and the adhesion between the adhesive film and the glass was tested. The test method was in accordance with the standard GB / T29848 "Ethylene-vinyl acetate copolymer (EVA) film for photovoltaic module encapsulation".

[0095] Thermal Cycling (TC) Test: The perovskite module structure is: glass / perovskite cell / low-modulus encapsulant film / crystalline silicon cell / encapsulant film / glass, including butyl sealant. After lamination for 20 minutes at 120℃ and 100kPa, the module is subjected to TC aging according to standard IEC61215-2. The initial power and power after 200 TC cycles are tested, and the power degradation rate of the perovskite layer cells is calculated using the following formula. Simultaneously, the module appearance is observed for any delamination.

[0096] Power degradation rate = (Initial module power - Power after 200 TC aging cycles) / Initial module power × 100%.

[0097] Table 1

[0098]

[0099]

[0100] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0101] The low-modulus encapsulating film for perovskite modules of this application includes a low-modulus layer. By controlling the elastic modulus of the low-modulus layer to be lower than 16MPa at 40℃, the overall modulus of the low-modulus encapsulating film for perovskite modules is reduced, thereby reducing the interfacial stress between the low-modulus encapsulating film and the perovskite cell during thermal cycling, thus avoiding the problem of interlayer delamination of the perovskite cell and improving the reliability of the perovskite module.

[0102] The above are merely embodiments of the present invention and are not intended to limit the invention. Those skilled in the art will recognize that the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low-modulus encapsulating film for perovskite modules, comprising a low-modulus layer, wherein the low-modulus layer is stacked facing the perovskite solar cell, characterized in that, The elastic modulus of the low modulus layer at 40℃ is less than 16MPa. The elastic modulus of the low modulus layer is tested using DMA. The sample of the low modulus layer is cut into strips 6mm wide, and the elastic modulus of the low modulus layer is tested in the range of 30℃~90℃ at an oscillation frequency of 1Hz using temperature scanning mode.

2. The low-modulus encapsulating film for perovskite modules according to claim 1, characterized in that, The low-modulus layer has an elastic modulus of 0.1~3MPa at 80℃.

3. The low-modulus encapsulating film for perovskite modules according to claim 1 or 2, characterized in that, The thickness of the low-modulus layer is not less than 0.2 mm, and preferably the thickness of the low-modulus layer is 0.2 mm to 0.6 mm.

4. The low-modulus encapsulating film for perovskite modules according to any one of claims 1 to 3, characterized in that, The low-modulus encapsulating film for the perovskite module is a cross-linked encapsulating film, comprising, by weight: 100 parts of the matrix resin; 5-50 parts of low modulus additive; 0.1 to 2 parts of crosslinking agent; 0.1 to 2 parts of crosslinking agent; 0.1 to 2 parts of silane coupling agent; 0-2 parts of light stabilizer; The low-modulus additive has an elastic modulus ≤16MPa at 40℃ and an elastic modulus of 0.1~3MPa at 80℃.

5. The low-modulus encapsulating film for perovskite modules according to any one of claims 1 to 3, characterized in that, The low-modulus encapsulating film for perovskite modules is a non-crosslinked film, comprising, by weight: 0-60 parts of matrix resin; 40-100 parts of thickening and modifying resin; 5-50 parts of low modulus additive; The total amount of the matrix resin and the tackifying and modifying resin is 100 parts; and / or, the elastic modulus of the low modulus additive is ≤16MPa at 40℃ and 0.1~3MPa at 80℃. The tackifying and modifying resin is selected from any one or more silane-modified POEs.

6. The low-modulus encapsulating film for perovskite modules according to claim 4 or 5, characterized in that, The viscosity of the low-modulus additive is not higher than 50,000 Pa·s, and preferably the viscosity of the low-modulus additive is 5,000 to 30,000 Pa·s.

7. The low-modulus encapsulating film for perovskite modules according to any one of claims 4 to 6, characterized in that, The low-modulus additive is selected from any one or more of liquid polyurethane rubber, liquid polybutadiene rubber, liquid polyisoprene rubber, liquid styrene-butadiene rubber, liquid pentadiene rubber, acrylic liquid rubber, polyamide liquid rubber, polyether polyol, polyester polyol, and liquid silicone rubber.

8. The low-modulus encapsulating film for perovskite modules according to any one of claims 1 to 7, characterized in that, The low-modulus encapsulating film used for the perovskite module is a single-layer film or a multi-layer film.

9. A perovskite module, comprising a low-modulus encapsulating film and a perovskite solar cell, wherein the low-modulus layer of the low-modulus encapsulating film is stacked facing the perovskite solar cell, characterized in that, The low-modulus encapsulating film is the low-modulus encapsulating film for perovskite components according to any one of claims 1 to 8.

10. The perovskite module according to claim 9, characterized in that, The perovskite module is a single-junction perovskite module or a perovskite-silicon tandem module; the coefficient of thermal expansion of the low-modulus encapsulating film is 120~280ppm / K. When the perovskite module is a single-junction perovskite module, the low-modulus encapsulating film further includes fillers, preferably selected from any one or more of ceramics, glass, silicon carbide, mullite, alumina, rutile, and graphite.

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