Ethylene / alpha-olefin copolymer for perovskite battery encapsulation and preparation method and application thereof

Abstract

This invention discloses an ethylene / α-olefin copolymer for perovskite battery encapsulation, its preparation method, and its application. The ethylene / α-olefin copolymer is obtained by polymerization of ethylene and at least one α-olefin as comonomers, and includes the following characteristics: a) a density of 0.860-0.910 g / cm³. 3 b) Hardness is 60-98 Shore A; c) 2.8 < [lgM]min < 4.5, 4.5 ≤ [lgM]max < 7, 0.02 < |[dWf / dlgM]max - [dWf / dlgM]min| ≤ 0.3. The ethylene / α-olefin copolymer can comprehensively improve the processability, light transmittance, and high-temperature creep resistance of the encapsulating film.

Description

Technical Field

[0001] This invention relates to a polyolefin material, and more particularly to an ethylene / α-olefin copolymer for perovskite battery encapsulation, its preparation method, and its application, belonging to the field of olefin polymerization technology. Background Technology

[0002] With the discovery of LDPE preparation via free radical polymerization in 1933, vinyl polyolefins have been developed for nearly a century. Later, LLDPE (Ziegler-Natta) and LLDPE (mPE) were also developed based on different catalysts, but their density is usually high and their hardness is also high due to the low insertion rate, making them difficult to use for modification of other polyolefin materials and other industrial applications. In the 1980s, Mobil and Dow introduced a solution-based low-pressure polyolefin elastomer process, which produced ethylene / α-olefin copolymers (POE) with higher insertion rates and lower molecular weight distributions, which have been widely used in automotive modification, shoe material foaming, and photovoltaic industries.

[0003] Perovskite solar cells, as a new generation of photovoltaic technology, have attracted much attention due to their excellent photoelectric conversion efficiency and low-cost fabrication process. However, unlike traditional crystalline silicon POE encapsulation films, perovskite POE encapsulation films are non-crosslinked formulations, requiring low creep at a long-term operating temperature of 85°C. Furthermore, due to the limitations of perovskite cell materials, the lamination processing temperature generally does not exceed 120°C. In contrast, traditional crystalline silicon POE has a lower melting point and poor creep resistance in the non-crosslinked state, but if a crosslinked system is formed, a lamination processing temperature of at least 145°C must be guaranteed, which cannot meet the requirements for perovskite cell encapsulation materials.

[0004] Existing technologies, such as WO2025231946A1, disclose an ethylene-α-olefin copolymer with a density of 0.860–0.905 g / cm³ and a weight-average molecular weight of 20,000–200,000 g / mol as determined by GPC. This copolymer exhibits high mechanical properties and good casting performance when used for encapsulating solar cells. However, its encapsulating film is still a cross-linked film, requiring a high lamination processing temperature, which can lead to the decomposition of perovskite solar cell materials. Therefore, it is not suitable as an encapsulating material for perovskite solar cells.

[0005] Therefore, developing high-performance perovskite battery encapsulation materials is of great significance for improving the application performance of perovskite batteries and expanding their applicable scenarios. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes an ethylene / α-olefin copolymer for perovskite battery encapsulation, its preparation method, and its application. The ethylene / α-olefin copolymer, through bimodal structure control and tight adjustment of peak height differences in GPC testing, can comprehensively improve the processability, light transmittance, and high-temperature creep resistance of the encapsulation film.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] An ethylene / α-olefin copolymer for perovskite battery encapsulation, wherein the ethylene / α-olefin copolymer is obtained by polymerization of ethylene and at least one α-olefin as comonomers, and includes the following characteristics:

[0009] a) Density is 0.860-0.910 g / cm³ 3 For example, it could be 0.860 g / cm³. 3 0.865g / cm 3 0.870 g / cm 3 0.875g / cm 3 0.880 g / cm 3 0.885g / cm 3 0.890 g / cm 3 0.895g / cm 3 0.90g / cm 3 0.905g / cm 3 Or 0.910 g / cm 3 ;

[0010] b) Hardness is 60-98 Shore A; for example, it can be 60A, 65A, 70A, 75A, 80A, 85A, 90A, 95A or 98A;

[0011] c) The gel permeation chromatogram contains at least two characteristic peaks detectable by gel permeation chromatography. The minimum abscissa value of the characteristic peak's vertex is denoted as [lgM]min, and the maximum abscissa value is denoted as [lgM]max. Then:

[0012] 2.8 < [lgM]min < 4.5,

[0013] 4.5 ≤ [lgM]max < 7,

[0014] 0.02<|[dWf / dlgM]max-[dWf / dlgM]min|≤0.3,

[0015] Where [dWf / dlgM]max is the maximum ordinate of the peak in the gel chromatography curve, and [dWf / dlgM]min is the minimum ordinate of the peak in the gel chromatography curve.

[0016] In the above formula, the value of [lgM]min can be, for example, 3, 3.3, 3.6, 3.9 or 4.2; the value of [lgM]max can be, for example, 4.6, 4.8, 5.1, 5.4, 5.7, 6.0, 6.3, 6.6 or 6.8; and the value of |[dWf / dlgM]max-[dWf / dlgM]min| can be, for example, 0.04, 0.08, 0.12, 0.16, 0.20, 0.24, 0.28.

[0017] The ethylene / α-olefin copolymer of this invention exhibits a bimodal distribution, which is beneficial for improving processability. The low molecular weight component acts as a plasticizer during melt processing, reducing melt viscosity and improving flowability, thereby reducing processing torque and energy consumption, and improving film uniformity. The high molecular weight component provides melt strength and mechanical support, preventing excessive flow or collapse of the film during high-temperature lamination or use. Furthermore, by controlling the peak height difference within a certain range, this invention facilitates the formation of a uniform microstructure, reduces large-scale crystallization or phase separation, thereby reducing light scattering and increasing the transmittance of the film in the ultraviolet and visible-near-infrared bands. Simultaneously, it synergistically enhances high-temperature creep resistance, thus designing and completing this invention.

[0018] As a preferred condition for the ethylene / α-olefin copolymer provided by the present invention, the melting temperature Tm of the ethylene / α-olefin copolymer is 80-120℃, for example, it can be 120℃, 115℃, 110℃, 105℃, 100℃, 95℃, 90℃, 85℃, 80℃, etc.

[0019] As a preferred condition for the ethylene / α-olefin copolymer provided by the present invention, the α-olefin insertion rate in the ethylene / α-olefin copolymer is 8-30 wt%; for example, it can be 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 25%, 26% or 28%, etc.

[0020] Preferably, the α-olefin is selected from one or more of propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-eicosene.

[0021] As a preferred condition for the ethylene / α-olefin copolymer provided by the present invention, the melt index of the ethylene / α-olefin copolymer at 190°C and 2.16 kg load is 0.3-40 g / 10 min, for example, it can be 1 g / 10 min, 4 g / 10 min, 7 g / 10 min, 10 g / 10 min, 13 g / 10 min, 16 g / 10 min, 19 g / 10 min, 22 g / 10 min, 25 g / 10 min, 28 g / 10 min, 31 g / 10 min, 34 g / 10 min, 36 g / 10 min or 38 g / 10 min, etc.

[0022] This invention, in its research on perovskite battery encapsulation materials, discovered that the GPC characteristic peak structure of the ethylene / α-olefin copolymer has a significant impact on the application performance of perovskite batteries. When the minimum and maximum abscissas of the characteristic peak apex in the gel permeation chromatography curve satisfy 2.8 < [lgM]min < 4.5 and 4.5 ≤ [lgM]max < 7, respectively, and the ordinate satisfies 0.02 < |[dWf / dlgM]max - [dWf / dlgM]min| ≤ 0.3, the perovskite battery encapsulation film prepared using this ethylene / α-olefin copolymer as the substrate not only exhibits good processability and creep resistance but also good light transmittance. However, when [lgM]min is lower than 2.8 or |[dWf / dlgM]max - [dWf / dlgM]min| exceeds 0.3, the creep resistance of the resulting encapsulation film deteriorates, and when [lgM]max is greater than 7, the light transmittance and processability of the product deteriorate.

[0023] The following is a reference example of how to obtain the ethylene / α-olefin copolymer for perovskite battery encapsulation described above, provided by this invention. It should be noted that, in addition to this preparation method, those skilled in the art can obtain the ethylene / α-olefin copolymer described above by combining other known polymerization methods with conventional adjustments, and this invention does not impose any limitations on this.

[0024] A method for preparing an ethylene / α-olefin copolymer for perovskite battery encapsulation includes the following steps: continuously feeding ethylene, α-olefin, solvent, catalyst and catalytic aid into a polymerization reactor, carrying out a copolymerization reaction under preset temperature and pressure conditions, quenching to terminate the polymerization after the reaction, and then performing post-processing steps of devolatilization, extrusion and granulation to obtain the ethylene / α-olefin copolymer.

[0025] The conditions for the copolymerization reaction are satisfied as follows:

[0026] ,

[0027] in, The effective volume of the polymerization reactor is expressed in dm³.3 ; The relative molecular mass of the comonomer; This represents the relative molecular mass of the ethylene monomer; The feed rate for the comonomer α-olefin is expressed in kg / h. This represents the feed rate of ethylene monomer, expressed in kg / h.

[0028] In the preparation method provided by the present invention, preferably, the pressure of the copolymerization reaction is 1-7 MPa;

[0029] Preferably, the temperature of the copolymerization reaction is 120-240℃.

[0030] In the preparation method provided by the present invention, preferably, the catalyst is selected from a transition metal organometallic complex containing at least one of cyclopentadienyl, indenyl, and fluorenyl ligands; wherein the transition metal is selected from titanium, zirconium, and hafnium;

[0031] Preferably, the catalyst is selected from di(pentamethylcyclopentadienyl)zirconium dichloride, racemic-ethyl-bridged bis(2-methylindenyl)zirconium dichloride, racemic-dimethylsilyl-bridged bis(2-methylindenyl)zirconium dichloride, racemic-dimethylsilyl-bridged fluorenylcyclopentadienylzirconium dichloride, silyl(N-tert-butylamino)(tetramethylcyclopentadienyl)titanium dichloride, disilyl(N-tert-butylamino)(tetramethylcyclopentadienyl)dimethyltitanium, disilyl(N-tert-butylamino)(fluorenyl)titanium dichloride, (pentamethylcyclopentadienyl)trimethoxytitanium, diphenylmethylene(cyclopentadiene)(9-fluorenyl)zirconium dichloride, dimethyldimethylsilylbis(2-methylindenyl)zirconium dichloride, and dimethyldimethylsilylbis(2-methylindenyl)zirconium dichloride. One or more of the following: (-methyl-4-phenyl-1-indene)zirconia, bis(methylcyclopentadiene)zirconia, bis(1,3-dimethylcyclopentadienyl)zirconia, (cyclopentadienyl)(1,2-dimethoxyethane)zirconia, diphenylsilyl(cyclopentadiene)(9-fluorenyl)zirconia, diphenylmethylenecyclopentadiene(2,7-di-tert-butylfluorenyl)zirconia, di-p-tolymethylenecyclopentadiene(2,7-di-tert-butylfluorenyl)zirconia, dimethylbis(propylcyclopentadienyl)hafnium, bis(n-butylcyclopentadiene)hafnium, and dimethylsilylbis(2-methyl-4-phenylindene)zirconia.

[0032] In the preparation method provided by the present invention, preferably, the catalyst includes at least one of alkylaluminum, aluminoxane, alkylaluminoxane and their alkyl-modified derivatives, and the amount of the catalyst, based on the molar ratio of aluminum to catalyst Al / MC, is 1-1000, preferably 10-200.

[0033] Preferably, the catalyst further comprises a borate compound; the borate compound is preferably trimethylammonium tetraphenylborate, methyl dioctadecylammonium tetraphenylborate, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, N,N-dimethylphenylammonium tetraphenylborate, trimethylammonium tetra(pentafluorophenyl)borate, methyl ditetradecylammonium tetra(pentafluorophenyl)borate, methyl dioctadecylammonium tetra(pentafluorophenyl)borate, triethylammonium tetra(pentafluorophenyl)borate, tripropylammonium tetra(pentafluorophenyl)borate, N,N-dimethyl ... - One or more of the following trisubstituted ammonium salt borate compounds: dimethylphenylammonium tetra(pentafluorophenyl)borate, trimethylammonium tetra(2,3,4,6-tetrafluorophenyl)borate, dimethyl(tert-butyl)ammonium tetra(2,3,4,6-tetrafluorophenyl)borate, N,N-dimethylphenylammonium tetra(2,3,4,6-tetrafluorophenyl)borate, dialkylammonium tetra(pentafluorophenyl)borate, ditetradecylammonium tetra(pentafluorophenyl)borate, or dicyclohexylammonium tetra(pentafluorophenyl)borate, and triphenylmethyltetra(pentafluorophenyl)borate.

[0034] Preferably, the amount of the borate compound used, based on the molar ratio of boron to catalyst (B / MC), is 0-10, more preferably 1-5, for example, 1, 2, 3, 4 or 5.

[0035] Preferably, the solvent is one or more of C6-C10 straight-chain alkanes, isoalkanes, cycloalkanes, aromatic alkanes, and mixed isoalkanes, and more preferably at least one of n-hexane, cyclohexane, methylcyclohexane, n-heptane, isoheptane, n-octane, isooctane, n-decane, toluene, xylene, and C8-C10 mixed isoalkanes (IsoparE).

[0036] Preferably, the feed rate of the solvent is 2-8 times the feed rate of the α-olefin.

[0037] Preferably, the quenching agent used for quenching is a water-alcohol mixture, more preferably a mixture of water and C2-C10 alcohol, wherein the weight ratio of water to C2-C10 alcohol is 0.1-10.

[0038] Preferably, the C2-C10 alcohol is selected from one or more of ethanol, propanol, butanol, 2-methylpropanol, pentanol, 2-methylbutanol, 3-methylbutanol, 2-ethylpropanol, hexanol, 2-methylpentanol, 3-methylpentanol, 4-methylbutanol, 3-ethylbutanol, heptanol, 2-methylhexanol, 3-methylhexanol, 4-methylhexanol, 5-methylhexanol, 3-ethylpentanol, 4-ethylpentanol, octanol, isooctanol, nonanol, isononol, and decanol.

[0039] The application of an ethylene / α-olefin copolymer for perovskite battery encapsulation as described above, or an ethylene / α-olefin copolymer for perovskite battery encapsulation prepared by the method described above, in the preparation of perovskite battery encapsulation films.

[0040] A perovskite battery encapsulation film composition includes the ethylene / α-olefin copolymer for perovskite battery encapsulation described above or the ethylene / α-olefin copolymer for perovskite battery encapsulation prepared by the method described above, and additives; said additives include crosslinking agents, coupling agents, and optionally antioxidants.

[0041] As a preferred feature of the encapsulating film composition, the crosslinking agent is selected from one or more of the following: tert-butyl peroxycarbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, bis-tert-butyl peroxydiisopropylbenzene, tert-butyl peroxy(2-ethylhexyl)carbonate, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-pentylperoxy)-3,3,5-trimethylcyclohexane, tert-pentyl peroxycarbonate, and tert-butyl peroxy3,3,5-trimethylhexanoate; the amount of the crosslinking agent is preferably 0.02-0.2% of the mass of the ethylene / α-olefin copolymer.

[0042] Preferably, the coupling agent is selected from one or more of vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane, and methacryloxypropyltrimethoxysilane; the amount of the coupling agent is preferably 0.5-5% of the mass of the ethylene / α-olefin copolymer.

[0043] Preferably, the antioxidant is selected from one or more of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and tris[2,4-di-tert-butylphenyl]phosphite. The amount of the antioxidant is preferably 0.05-1% of the mass of the ethylene / α-olefin copolymer.

[0044] A method for preparing a perovskite battery encapsulating film using the perovskite battery encapsulating film composition described above includes the following steps:

[0045] 1) Thoroughly mix the ethylene / α-olefin copolymer, crosslinking agent, coupling agent and optionally antioxidant, put them into a vacuum mixer, and mix and melt them at 150-200℃ and vacuum degree of -0.01Mpa to 0.098Mpa for 1-10 minutes to obtain a homogeneous melt;

[0046] 2) Transfer the melt to a tablet press and hot-press it to obtain an encapsulating film;

[0047] Preferably, the mixing and melting speed in step 1 is 20-60 r / min;

[0048] Preferably, the hot pressing conditions in step 2) are 100-130℃ and 5-10MPa for 2-5 minutes.

[0049] The ethylene / α-olefin copolymer provided by this invention exhibits high creep resistance in the preparation of perovskite battery materials under non-crosslinked systems and low lamination temperatures. At the same time, the product has good processability and high light transmittance, demonstrating significant application advantages. Detailed Implementation

[0050] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0051] The main raw materials used in the following examples and comparative examples are all commercially available. Key information is as follows:

[0052] Ethylene, 99.95% (V / V), Beijing Helium Pro.

[0053] 1-Octenene, 98%, INEOS;

[0054] 1-Butene, 99%, light source;

[0055] 1-Hexene, 99%, Sinopec;

[0056] IsoparE: C8-C10 mixed isoalkanes, C8 70-80%, C9 20-30%, C10 <10%, ExxonMobil;

[0057] Racemic-dimethylsilyl-bridged bis(2-methylindenyl)zirconium dichloride, 98%, Aladdin, denoted as M1;

[0058] Dimethicone (N-tert-butylamino) (tetramethylcyclopentadienyl) dimethyltitanium, 98%, Yanfeng Technology, designated as M2;

[0059] MMAO: 7% Al, Noryon, denoted as B1;

[0060] Trimethylammonium tetra(2,3,4,6-tetrafluorophenyl)borate, 98%, Aladdin, denoted as B2;

[0061] Di-tert-butyl peroxide dicumylbenzene, 98%, Lanzhou Additives Factory;

[0062] Vinyltrimethoxysilane, 99%, Jiangxi Chenguang New Materials;

[0063] β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol ester, 98%, Tianjin Lialong.

[0064] The main testing methods involved in the following embodiments of the present invention are as follows:

[0065] (1) Density: Measured according to ASTM D-792.

[0066] (2) Melt flow index: determined according to ASTM D-1238 (conditions: 190℃, 2.16Kg load).

[0067] (3) Hardness Shore A: Measured according to ASTM D-2240.

[0068] (4) Gel permeation chromatography curve: Obtained using gel permeation chromatography (GPC). Specifically, the chromatographic column was an Agilent Olexis; the solvent was trichlorobenzene; the flow rate was 1.0 ml / min; the sample concentration was 1.0 mg / ml; the injection volume was 200 μl; the column temperature was 160 °C; the detector was an Agilent High Temperature RI detector; and the standard was polystyrene (corrected using a cubic function).

[0069] (5) Melting temperature: This was obtained using a Differential Scanning Calorimeter (DSC6000) manufactured by PerkinElmer. Specifically, under a nitrogen atmosphere, the sample temperature was raised to 150°C using DSC and maintained for 5 minutes, then cooled to -100°C, and the temperature was raised again before observing the DSC curve. The heating and cooling rates were 10°C / min.

[0070] (6) Transmittance: The transmittance of the film was tested according to the spectrophotometer method of GB / T2410-2008, and the average values ​​of the wavelength ranges of 290nm-380nm and 380nm-1100nm were calculated respectively.

[0071] (7) Creep resistance at 115℃: measured according to the following method;

[0072] Cut the adhesive film into 50mm x 50mm pieces, and sandwich it between two 3.2mm thick patterned glass rough surfaces, each 50mm long and 100mm high, ensuring the top edges are flush. Overlap the pieces with a 50mm x 50mm bonding area and laminate at 120℃ for 14 minutes. Place the resulting bonded body vertically in a 115℃ oven and let it stand for 48 hours. Measure the glass offset after removal, using this as an indicator of high-temperature creep resistance.

[0073] [Examples and Comparative Examples]

[0074] Following the specific process conditions in Table 1, the polymerization of ethylene and α-olefins was carried out in a continuous batch reactor. Solvent IsoparE, α-olefins, and ethylene were continuously fed into the reactor after deoxygenation and dehydration in a fixed bed. The catalyst and catalytic aids were prepared into solutions and then supplied to the reactor. The batch reactor was fed from the bottom and discharged from the top. The heat exchanger before the reactor and the reactor jacket controlled the reaction at the specified temperature. The pressure was controlled by a pneumatic proportional control valve at the reactor outlet. After the polymerization reaction was completed, the polymerization was terminated with a quencher (water and ethanol = 4:1, v / v). The melt was sampled for analysis after devolatilization and granulation.

[0075] Table 1. Process parameters of Examples 1-5 and Comparative Examples 1-3

[0076]

[0077] The physical properties of the ethylene / α-olefin copolymers provided in the various examples and comparative examples, as well as the commercially available brand Wanhua F6098, were analyzed, and the results are shown in Table 2:

[0078] Table 2. Physical property analysis of ethylene / α-olefin copolymers

[0079]

Application Example

[0080] Using the ethylene / α-olefin copolymers provided in each embodiment and comparative example as raw materials, the encapsulation films were prepared according to the following process methods:

[0081] 100 parts by weight of ethylene / α-olefin copolymer, 0.07 parts by weight of crosslinking agent (di-tert-butyl peroxide dicumylbenzene), 3 parts by weight of silane coupling agent (vinyltrimethoxysilane), and 0.1 parts by weight of antioxidant (β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol ester) were mixed evenly and added to a vacuum mixer. The mixture was melted and mixed at 180°C and a vacuum of -0.06 MPa for 5 minutes to obtain a homogeneous melt. The melt was transferred to a tablet press, the film thickness was adjusted to 0.6 mm, and the film was hot-pressed at 120°C and 8 MPa for 3 minutes. After opening the mold and cooling, the encapsulating film was obtained.

[0082] Table 3. Application Performance of Encapsulating Films

[0083]

[0084] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. An ethylene / α-olefin copolymer for encapsulating perovskite solar cells, characterized in that, The ethylene / α-olefin copolymer is obtained by polymerization of ethylene and at least one α-olefin as comonomers, and includes the following characteristics: a) Density is 0.860-0.910 g / cm³ 3 ; b) Hardness is 60-98 Shore A; c) The curve contains at least two characteristic peaks detectable by gel permeation chromatography. The minimum abscissa value of the peak in the gel permeation chromatography curve is denoted as [lgM]min, and the maximum abscissa value is denoted as [lgM]max. Therefore: 2.8 < [lgM]min < 4.

5. 4.5 ≤ [lgM]max < 7, 0.02<|[dWf / dlgM]max-[dWf / dlgM]min|≤0.3, Where [dWf / dlgM]max is the maximum ordinate of the peak in the gel chromatography curve, and [dWf / dlgM]min is the minimum ordinate of the peak in the gel chromatography curve.

2. The ethylene / α-olefin copolymer for perovskite battery encapsulation according to claim 1, characterized in that, The melting temperature Tm of the ethylene / α-olefin copolymer is 80-120℃.

3. The ethylene / α-olefin copolymer for perovskite battery encapsulation according to claim 1, characterized in that, In the ethylene / α-olefin copolymer, the α-olefin insertion rate is 8-30 wt%; Preferably, the α-olefin is selected from one or more of propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-eicosene.

4. The ethylene / α-olefin copolymer for perovskite battery encapsulation according to any one of claims 1-3, characterized in that, The ethylene / α-olefin copolymer has a melt index of 0.3-40 g / 10 min at 190°C and a load of 2.16 kg.

5. A method for preparing an ethylene / α-olefin copolymer for perovskite battery encapsulation as described in any one of claims 1-4, characterized in that, Includes the following steps: Ethylene, α-olefin, solvent, catalyst and catalytic aid are continuously fed into a polymerization reactor and copolymerized under preset temperature and pressure conditions. After the reaction is completed, the polymerization is terminated by quenching. The copolymer is then subjected to post-processing steps such as devolatilization, extrusion and granulation to obtain the ethylene / α-olefin copolymer. The conditions for the copolymerization reaction are satisfied as follows: ， in, The effective volume of the polymerization reactor is expressed in dm³. 3 ; The relative molecular mass of the comonomer; This represents the relative molecular mass of the ethylene monomer; The feed rate of the comonomer α-olefin is expressed in kg / h. This represents the feed rate of ethylene monomer, expressed in kg / h.

6. The method for preparing the ethylene / α-olefin copolymer for perovskite battery encapsulation according to claim 5, characterized in that, The pressure of the copolymerization reaction is 1-7 MPa; Preferably, the temperature of the copolymerization reaction is 120-240℃.

7. The method for preparing the ethylene / α-olefin copolymer for perovskite battery encapsulation according to claim 5, characterized in that, The catalyst is selected from transition metal organometallic complexes containing at least one of cyclopentadienyl, indenyl, and fluorenyl ligands; Preferably, the catalyst is selected from di(pentamethylcyclopentadienyl)zirconium dichloride, racemic-ethyl-bridged bis(2-methylindenyl)zirconium dichloride, racemic-dimethylsilyl-bridged bis(2-methylindenyl)zirconium dichloride, racemic-dimethylsilyl-bridged fluorenylcyclopentadienylzirconium dichloride, silyl(N-tert-butylamino)(tetramethylcyclopentadienyl)titanium dichloride, disilyl(N-tert-butylamino)(tetramethylcyclopentadienyl)dimethyltitanium, disilyl(N-tert-butylamino)(fluorenyl)titanium dichloride, (pentamethylcyclopentadienyl)trimethoxytitanium, diphenylmethylene(cyclopentadiene)(9-fluorenyl)zirconium dichloride, dimethyldimethylsilylbis(2-methylindenyl)zirconium dichloride, and dimethyldimethylsilylbis(2-methylindenyl)zirconium dichloride. One or more of the following: (-methyl-4-phenyl-1-indene)zirconia, bis(methylcyclopentadiene)zirconia, bis(1,3-dimethylcyclopentadienyl)zirconia, (cyclopentadienyl)(1,2-dimethoxyethane)zirconia, diphenylsilyl(cyclopentadiene)(9-fluorenyl)zirconia, diphenylmethylenecyclopentadiene(2,7-di-tert-butylfluorenyl)zirconia, di-p-tolymethylenecyclopentadiene(2,7-di-tert-butylfluorenyl)zirconia, dimethylbis(propylcyclopentadienyl)hafnium, bis(n-butylcyclopentadiene)hafnium, and dimethylsilylbis(2-methyl-4-phenylindene)zirconia.

8. The method for preparing the ethylene / α-olefin copolymer for perovskite battery encapsulation according to any one of claims 5-7, characterized in that, The catalyst promoter includes at least one of alkylaluminum, aluminumoxane, alkylaluminoxane, and their alkyl-modified derivatives; Preferably, the catalyst further comprises a borate compound; the borate compound is preferably trimethylammonium tetraphenylborate, methyl dioctadecylammonium tetraphenylborate, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, N,N-dimethylphenylammonium tetraphenylborate, trimethylammonium tetra(pentafluorophenyl)borate, methyl ditetradecylammonium tetra(pentafluorophenyl)borate, methyl dioctadecylammonium tetra(pentafluorophenyl)borate, triethylammonium tetra(pentafluorophenyl)borate, tripropylammonium tetra(pentafluorophenyl)borate, N,N-dimethyl ... - One or more of the following trisubstituted ammonium salt borate compounds: dimethylphenylammonium tetra(pentafluorophenyl)borate, trimethylammonium tetra(2,3,4,6-tetrafluorophenyl)borate, dimethyl(tert-butyl)ammonium tetra(2,3,4,6-tetrafluorophenyl)borate, N,N-dimethylphenylammonium tetra(2,3,4,6-tetrafluorophenyl)borate, dialkylammonium tetra(pentafluorophenyl)borate, ditetradecylammonium tetra(pentafluorophenyl)borate, or dicyclohexylammonium tetra(pentafluorophenyl)borate, and triphenylmethyltetra(pentafluorophenyl)borate.

9. The application of an ethylene / α-olefin copolymer for perovskite battery encapsulation as described in claims 1-4 or an ethylene / α-olefin copolymer for perovskite battery encapsulation prepared by the method described in any one of claims 5-8 in the preparation of a perovskite battery encapsulation film.

10. A perovskite battery encapsulation film composition, characterized in that, The invention includes the ethylene / α-olefin copolymer for perovskite battery encapsulation as described in any one of claims 1-4 or the ethylene / α-olefin copolymer for perovskite battery encapsulation prepared by the method described in any one of claims 5-8, and additives; said additives include crosslinking agents, coupling agents and optionally antioxidants.

11. The perovskite battery encapsulation film composition according to claim 10, characterized in that, The crosslinking agent is selected from one or more of the following: tert-butyl peroxycarbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, bis-tert-butyl peroxydiisopropylbenzene, tert-butyl peroxy(2-ethylhexyl)carbonate, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-pentylperoxy)-3,3,5-trimethylcyclohexane, tert-pentyl peroxycarbonate, and tert-butyl peroxy3,3,5-trimethylhexanoate. Preferably, the coupling agent is selected from one or more of vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane, and methacryloxypropyltrimethoxysilane; Preferably, the antioxidant is selected from one or more of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and tris[2,4-di-tert-butylphenyl]phosphite.

12. A method for preparing a perovskite battery encapsulating film using the perovskite battery encapsulating film composition according to claim 10 or 11, characterized in that, Includes the following steps: 1) Thoroughly mix the ethylene / α-olefin copolymer, crosslinking agent, coupling agent and optionally antioxidant, put them into a vacuum mixer, and mix and melt them at 150-200℃ and vacuum degree of -0.01Mpa to 0.098Mpa for 1-10 minutes to obtain a homogeneous melt; 2) Transfer the melt to a tablet press and hot-press it to obtain an encapsulating film; Preferably, the mixing and melting speed in step 1 is 20-60 r / min; Preferably, the hot pressing conditions in step 2) are 100-130℃ and 5-10MPa for 2-5 minutes.

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