Battery cell, battery, rubber sealing member, manufacturing method therefor, and electrical apparatus

Abstract

The present application relates to a battery cell, a battery, a rubber sealing member, a manufacturing method therefor, and an electrical apparatus. The battery cell comprises: a housing having an opening; a cell assembly accommodated in the housing; an end cover provided at the opening and sealing the opening; electrode terminals provided on the end cover and used for connecting to the cell assembly; rubber sealing members, each rubber sealing member provided between an electrode terminal and the end cover and sealing the electrode terminal; each rubber sealing member comprises hydrogenated nitrile rubber and ethylene propylene diene monomer rubber, the hydrogenated nitrile rubber having an average molecular weight of one hundred thousand to one million.

Description

Battery cell, battery, rubber seal, preparation method thereof and electric device

[0001] Related applications

[0002] The present application claims priority to the Chinese patent application No. 2024113368119, filed on September 24, 2024, and entitled "Battery cell, battery, rubber seal, preparation method thereof and electric device", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present application belongs to the technical field of battery, in particular to a battery cell, a battery, a rubber seal, a preparation method thereof and an electric device. BACKGROUND

[0004] Batteries are widely used in various consumer electronic products and electric vehicles. The service life of the battery in low temperature environment is the performance that users focus on. The current battery has the problem of low service life in low temperature environment. SUMMARY

[0005] Therefore, it is necessary to provide a battery cell, a battery and an electric device, which can improve the service life of the battery and the battery cell. In addition, a rubber seal and a preparation method thereof are also provided.

[0006] In a first aspect, the present application provides a battery cell, comprising:

[0007] a shell having an opening;

[0008] a cell assembly accommodated in the shell;

[0009] an end cover sealingly arranged at the opening;

[0010] an electrode terminal arranged on the end cover and used for connecting with the cell assembly; and

[0011] a rubber seal sealingly arranged between the electrode terminal and the end cover; the rubber seal comprises hydrogenated nitrile rubber and ethylene propylene diene rubber, and the weight average molecular weight of the hydrogenated nitrile rubber is 100,000-1,000,000.

[0012] Therefore, the rubber seal applied in the battery cell of the present application is prepared by compounding the hydrogenated nitrile rubber (HNBR) with the specific weight average molecular weight and the ethylene propylene diene rubber (EPDM), which has good high and low temperature resistance, insulation performance and chemical resistance, especially electrolyte swelling resistance. In addition, better compression resistance can be obtained, so that good sealing performance can be provided, thereby improving the service life of the battery and the battery cell.

[0013] In some embodiments, at least one of the following conditions is satisfied:

[0014] (1) the rubber seal comprises a co-sulfide of hydrogenated nitrile rubber and ethylene-propylene-diene rubber;

[0015] (2) the hydrogenated nitrile rubber has an acrylonitrile content of 15wt% to 45wt%;

[0016] (3) the hydrogenated nitrile rubber has a hydrogenation degree of ≥80%;

[0017] (4) the hydrogenated nitrile rubber has a weight average molecular weight of 200,000 to 450,000.

[0018] The higher the acrylonitrile content of the hydrogenated nitrile rubber, the higher the tensile strength, heat resistance, oil resistance, air tightness, and hardness, but the lower the low-temperature resistance. Therefore, further controlling the acrylonitrile content of the hydrogenated nitrile rubber within the range can make the rubber seal have better high and low temperature resistance, insulation performance, and chemical resistance, especially electrolyte swelling resistance.

[0019] The hydrogenation degree of the hydrogenated nitrile rubber within the range can have better heat resistance, low-temperature resistance, ozone resistance, chemical resistance, and mechanical strength.

[0020] The weight average molecular weight of the hydrogenated nitrile rubber within the range can make the rubber seal have better low-temperature resistance, insulation performance, and further improve its elongation at break and chemical resistance, especially electrolyte swelling resistance, and further improve the service life of the battery and battery cell.

[0021] In some embodiments, at least one of the following conditions is satisfied:

[0022] (1) the rubber seal comprises a co-sulfide of hydrogenated nitrile rubber and ethylene-propylene-diene rubber;

[0023] (2) the ethylene content of the ethylene-propylene-diene rubber is 55wt% to 70wt%;

[0024] (3) the third monomer content of the ethylene-propylene-diene rubber is 3wt% to 8wt%;

[0025] (4) the Mooney viscosity ML(1+4)100℃ of the ethylene-propylene-diene rubber is 20 to 80.

[0026] A higher ethylene content can enhance the intermolecular force in the rubber, significantly improve the mechanical properties such as tensile strength and elongation at break, improve the mechanical strength and wear resistance of the seal, and improve the service life.

[0027] The third monomer content in the above range can improve the electrolyte swelling resistance and compression resistance of the rubber seal.

[0028] The use of the above-mentioned lower Mooney viscosity EPDM rubber has excellent processability and saves energy consumption, and at the same time, can help the reinforcing filler in the raw materials for the preparation of the rubber seal to be uniformly dispersed in the rubber seal, and a relatively soft and stable performance rubber compound can be obtained without any other softening agent.

[0029] In some embodiments, the hydrogenated nitrile rubber is 100 parts by weight in the rubber seal, and the EPDM rubber is 10-40 parts by weight.

[0030] In some embodiments, the rubber seal further comprises one or more of a reinforcing filler, an insulating filler and a processing aid.

[0031] In some embodiments, the hydrogenated nitrile rubber is 100 parts by weight in the rubber seal, and the rubber seal further satisfies at least one of the following conditions:

[0032] (1) further comprising 30-70 parts by weight of a reinforcing filler in the rubber seal;

[0033] (2) further comprising 10-30 parts by weight of an insulating filler in the rubber seal;

[0034] (3) further comprising 4-12 parts by weight of a processing aid in the rubber seal.

[0035] In some embodiments, at least one of the following conditions is satisfied:

[0036] (1) the reinforcing filler comprises at least one of carbon black, white carbon black, calcium carbonate, talc powder, mica powder and montmorillonite;

[0037] (2) the insulating filler comprises at least one of barium sulfate and kaolin;

[0038] (3) the processing aid comprises at least one of a fatty acid derivative and an organic acid ester compound.

[0039] In some embodiments, at least one of the following conditions is satisfied:

[0040] (1) the fatty acid derivative comprises at least one of stearic acid, zinc stearate, magnesium stearate, calcium stearate, potassium stearate and sodium stearate;

[0041] (2) the organic acid ester compound comprises at least one of trioctyl trimellitate, diisononyl phthalate and dioctyl sebacate.

[0042] In some embodiments, the raw materials for preparing the rubber seal further include one or more of vulcanizing agents, vulcanization activators, vulcanization accelerators, and compatibilizers.

[0043] In some embodiments, the hydrogenated nitrile rubber is 100 parts by weight in the rubber seal, and the rubber seal further satisfies at least one of the following conditions:

[0044] (1) further including 4-12 parts by weight of vulcanizing agents in the rubber seal;

[0045] (2) further including 2-10 parts by weight of vulcanization activators in the rubber seal;

[0046] (3) further including 0.5-4 parts by weight of vulcanization accelerators in the rubber seal;

[0047] (4) further including 0-20 parts by weight of compatibilizers in the rubber seal.

[0048] In some embodiments, the rubber seal includes 100 parts by weight of the hydrogenated nitrile rubber, 10-40 parts by weight of the ethylene-propylene-diene rubber, 30-70 parts by weight of reinforcing fillers, 10-30 parts by weight of insulating fillers, 4-12 parts by weight of processing aids, 4-12 parts by weight of vulcanizing agents, 2-10 parts by weight of vulcanization activators, 0.5-4 parts by weight of vulcanization accelerators, and 0-20 parts by weight of compatibilizers. Controlling the above raw materials within the above ranges can improve the processing performance of HNBR rubber products, and the rubber seal prepared under the condition of relatively good low-temperature resistance, insulation, and electrolyte swelling resistance has further improved compression resistance and elongation at break, thereby improving the service life of the rubber seal, the battery, and the battery cell.

[0049] In some embodiments, the rubber seal includes 100 parts by weight of the hydrogenated nitrile rubber, 20-30 parts by weight of the ethylene-propylene-diene rubber, 50-60 parts by weight of reinforcing fillers, 20-30 parts by weight of insulating fillers, 6-8 parts by weight of processing aids, 6-8 parts by weight of vulcanizing agents, 4-6 parts by weight of vulcanization activators, 2-3 parts by weight of vulcanization accelerators, and 5-20 parts by weight of compatibilizers.

[0050] In some embodiments, at least one of the following conditions is satisfied:

[0051] (1) the vulcanizing agents include at least one of peroxide vulcanizing agents, sulfur vulcanizing agents, and metal oxide vulcanizing agents;

[0052] (2) the vulcanization activators include metal oxide vulcanization activators;

[0053] (3) the co-agents include at least one of zinc dimethacrylate, triallyl cyanurate, triallyl isocyanurate, and bismaleimide;

[0054] (4) the compatibilizers include at least one of chlorinated polyethylene and chlorosulfonated polyethylene.

[0055] In some embodiments, at least one of the following conditions is satisfied:

[0056] (1) the metal oxide vulcanization activators include at least one of zinc oxide and magnesium oxide;

[0057] (2) the peroxide vulcanization agents include at least one of dicumyl peroxide, di(tert-butylperoxy isopropyl)benzene, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane.

[0058] In some embodiments, at least one of the following conditions is satisfied:

[0059] (1) the rubber seal has a mass change rate of < 20% and a volume expansion rate of < 23% when immersed in dimethyl carbonate solvent at 70°C for 72h;

[0060] (2) the rubber seal has a compression set of < 24% after compression at 120°C for 9 days, as tested according to national standard GB / T 7759.1;

[0061] (3) the rubber seal has a volume resistivity of > 10 x 10 10 Ω·cm at a test voltage of 500V, as tested according to national standard GBT 31838.2-2019;

[0062] (4) the rubber seal has a tensile strength of > 15 MPa and an elongation at break of > 150%;

[0063] (5) the rubber seal has a low-temperature brittleness temperature of between -54.5°C and -49°C;

[0064] (6) the rubber seal has a Shore A hardness of 65-85.

[0065] In some embodiments, at least one of the following conditions is satisfied:

[0066] (1) the rubber seal has a mass change rate of < 20% and a volume expansion rate of < 23% when immersed in dimethyl carbonate solvent at 70°C for 72h;

[0067] (2) the rubber seal has a compression set of < 24% after compression at 120°C for 9 days, as tested according to national standard GB / T 7759.1;

[0068] (3) The volume resistivity of the rubber sealing piece is > 50 x 10 10 Ω·cm under a test voltage of 500 V according to the national standard GBT 31838.2-2019.

[0069] (4) The tensile strength of the rubber sealing piece is ≥ 19 MPa, and the elongation at break is ≥ 200%.

[0070] (5) The Shore A hardness of the rubber sealing piece is 65-76.

[0071] In some embodiments, the electric core assembly includes a positive electrode sheet, a separator film and a negative electrode sheet arranged in a stack; and the battery monomer further includes an electrolyte, which is arranged in the shell and infiltrates the electric core assembly.

[0072] In a second aspect, the application provides a preparation method of a rubber sealing piece, including the following steps:

[0073] Mixing preparation raw materials to obtain a rubber compound; the preparation raw materials include hydrogenated nitrile rubber, ethylene propylene terpolymer rubber and a vulcanizing agent, and the weight average molecular weight of the hydrogenated nitrile rubber is 100-1,000,000.

[0074] Sulfurizing and forming the rubber compound to obtain a rubber sealing piece.

[0075] In some embodiments, at least one of the following conditions is met:

[0076] (1) The acrylonitrile content of the hydrogenated nitrile rubber is 15-45 wt%.

[0077] (2) The hydrogenation degree of the hydrogenated nitrile rubber is ≥ 80%.

[0078] (3) The weight average molecular weight of the hydrogenated nitrile rubber is 200-450,000.

[0079] (4) The ethylene content of the ethylene propylene terpolymer rubber is 55-70 wt%.

[0080] (5) The third monomer content of the ethylene propylene terpolymer rubber is 3-8 wt%.

[0081] (6) The Mooney viscosity ML(1+4)100℃ of the ethylene propylene terpolymer rubber is 20-80.

[0082] (7) In the rubber sealing piece, the hydrogenated nitrile rubber is 100 parts, the ethylene propylene terpolymer rubber is 10-40 parts, and the vulcanizing agent is 4-12 parts by weight.

[0083] In some embodiments, the preparation raw material further comprises one or more of reinforcing fillers, insulating fillers, processing aids, vulcanization activators, vulcanization aids, and compatibilizers.

[0084] In some embodiments, the hydrogenated nitrile rubber is 100 parts by weight in the rubber seal, and the rubber seal further satisfies at least one of the following conditions:

[0085] (1) further comprising reinforcing fillers 30-70 parts by weight in the rubber seal;

[0086] (2) further comprising insulating fillers 10-30 parts by weight in the rubber seal;

[0087] (3) further comprising processing aids 4-12 parts by weight in the rubber seal;

[0088] (4) further comprising vulcanization activators 2-10 parts by weight in the rubber seal;

[0089] (5) further comprising vulcanization aids 0.5-4 parts by weight in the rubber seal;

[0090] (6) further comprising compatibilizers 0-20 parts by weight in the rubber seal.

[0091] In some embodiments, the temperature of the vulcanization molding is 140-200℃, and the pressure of the vulcanization molding is 8-20 MPa.

[0092] In a third aspect, the present application provides a rubber seal, as defined in the rubber seal in the battery cell of the first aspect of the present application, or prepared by the preparation method of the second aspect of the present application.

[0093] In a fourth aspect, the present application provides a battery comprising at least one of the battery cell of the first aspect of the present application and the rubber seal of the third aspect of the present application.

[0094] In a fifth aspect, the present application provides an electric device comprising at least one of the battery cell of the first aspect of the present application, the rubber seal of the third aspect of the present application, and the battery of the fourth aspect of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0095] In order to more clearly illustrate the technical solutions of the present application, the drawings used in the present application will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the drawings.

[0096] FIG. 1 is a schematic view of a power consuming device using a battery as a power source according to an embodiment of the present application;

[0097] FIG. 2 is an exploded structural view of the battery according to an embodiment of the present application shown in FIG. 1;

[0098] FIG. 3 is an exploded structural view of a battery cell in the battery according to an embodiment of the present application;

[0099] FIG. 4 is a plan view of the battery cell in the battery according to an embodiment of the present application;

[0100] FIG. 5 is an exploded structural view of an end cap, an electrode terminal, and a rubber seal of the battery cell shown in FIG. 4;

[0101] FIG. 6 is a partial cross-sectional view of the end cap of the battery cell shown in FIG. 4 along line A-A.

[0102] Reference Signs: 1000, power consuming device; 100, battery; 200, controller; 300, motor; 20, battery cell; 21, end cap; 22, case; 23, electrode assembly; 21a, electrode terminal; 23a, tab; 231, mounting hole; 25, rubber seal. DETAILED DESCRIPTION

[0103] Hereinafter, embodiments of the battery, the manufacturing method, and the power consuming device according to the present application are specifically disclosed while appropriately referring to the accompanying drawings. However, there are cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of matters that are well known, repeated descriptions of actually identical structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided so that those skilled in the art can fully understand the present application, and are not intended to limit the subject matter recited in the claims.

[0104] The ranges disclosed herein are intended to be "open" ranges, i.e., the upper and lower limits of the range are not included. The ranges are also intended to include any and all sub-ranges of the same, wherein each sub-range is inclusive of the end values. For example, if a range is from 1 to 10, then the range includes any and all sub-ranges between (and including) the minimum of 1 and the maximum of 10, that is, any of 1 to 3, 4 to 6, 5 to 9, 3 to 7, 2 to 12, 10 to 10, etc. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of "1 to 10" is intended to include all sub-ranges between (and including) the minimum of 1 and the maximum of 10, that is, any one of 1 to 3, 4 to 6, 5 to 9, 3 to 7, 2 to 12, 10 to 10, etc. In this disclosure and in the claims, the term "range" means an inclusion of all sub-ranges between (and including) the minimum and maximum values of the range. For example, a range of "1 to 10" means any of 1 to 3, 4 to 6, 5 to 9, 3 to 7, 2 to 12, 10 to 10, etc. In this disclosure and in the claims, the term "sub-range" means an inclusion of all sub-ranges between (and including) the minimum and maximum values of the sub-range. For example, a sub-range of "1 to 10" means any of 1 to 3, 4 to 6, 5 to 9, 3 to 7, 2 to 12, 10 to 10, etc. In this disclosure and in the claims, the term "integer" means an inclusion of all integers between (and including) the minimum and maximum values of the integer. For example, an integer of "2" means any of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0105] All embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions, unless otherwise specified.

[0106] All technical features and optional technical features of the present application can be combined with each other to form new technical solutions, unless otherwise specified.

[0107] Unless otherwise specified, all steps of the present application can be performed in sequence or randomly, and preferably in sequence. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) in sequence, or steps (b) and (a) in sequence. For example, the method also comprises step (c), which means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0108] Unless otherwise specified, the terms used in the present application have the commonly understood meanings understood by those skilled in the art. Unless otherwise specified, the values of each parameter mentioned in the present application can be measured by various measurement methods commonly used in the art (for example, the test can be performed according to the method given in the examples of the present application).

[0109] At present, from the development of market situation, the application of power battery is more and more widely. The power battery is not only applied to the energy storage power supply system of water power, fire power, wind power and solar power station, but also widely used in electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, military equipment, aerospace and other fields. With the continuous expansion of the application field of power battery, the demand of its market is also increasing.

[0110] The technical personnel of the present application notice that the sealing of the electrolyte in the battery monomer is particularly important, and the sealing element arranged between the electrode terminal and the end cover is the key material related to the sealing performance. The main material of the sealing element at present is fluorine rubber, however, on the one hand, fluorine rubber contains fluorine element, which will cause pollution damage to the ecological environment and harm to human health, on the other hand, the fluorine atom in fluorine rubber has strong polarity and large intermolecular force, so the glass transition temperature of fluorine rubber is high, and therefore the mechanical properties such as elastic modulus and tensile strength will sharply decrease at low temperature, and the low temperature performance of fluorine rubber is not good.

[0111] Since the use environment of the sealing element in the battery monomer inevitably contacts with the electrolyte, it is long-term corroded by the electrolyte, in addition, since the sealing element is tightly arranged between the devices and belongs to compression state for a long time, in addition to the requirements of low temperature resistance, insulation performance, the sealing element is also required to have good compression resistance and chemical resistance, especially electrolyte swelling resistance.

[0112] The technical personnel further found that the main deficiency of the sealing material applied in the battery at present is that the compression resistance and chemical resistance, especially the electrolyte swelling resistance are not good, the sealing material deforms seriously or absorbs the electrolyte in the battery to swell after a period of use, thus leading to the decrease of the service life and sealing performance of the sealing material. Based on this, the present application proposes a new rubber sealing element applied in the battery monomer, which not only does not contain fluorine element, but also has good low temperature resistance, insulation performance, compression resistance and chemical resistance, especially electrolyte swelling resistance, so as to improve the service life of the battery and the battery monomer.

[0113] The battery monomer disclosed in the embodiments of the present application can be used in electric devices such as vehicles, ships or aircraft, etc. The power supply system of the electric device can be composed of the battery monomer and the battery disclosed in the present application, which is advantageous to improve the sealing performance of the battery monomer and the service life of the battery and the battery monomer.

[0114] The embodiments of the present application provide a power consumption device using a battery as a power supply. The power consumption device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric automobile, a ship, a spacecraft, and the like. The electric toy can include a fixed or mobile electric toy, such as a game console, an electric automobile toy, an electric ship toy, an electric aircraft toy, and the like. The spacecraft can include an airplane, a rocket, a space shuttle, a spacecraft, and the like.

[0115] The following embodiments are described by taking a power consumption device of an embodiment of the present application as a vehicle 1000 for example for convenience of description.

[0116] Referring to FIG. 1, FIG. 1 is a structural schematic diagram of a vehicle 1000 provided by some embodiments of the present application. The vehicle 1000 can be a fuel automobile, a gas automobile, or a new energy automobile. The new energy automobile can be a pure electric automobile, a hybrid electric automobile, or a range extended automobile. The vehicle 1000 is internally provided with a battery 100. The battery 100 can be arranged at a bottom, a head, or a tail of the vehicle 1000. The battery 100 can be used for power supply of the vehicle 1000, for example, the battery 100 can be used as an operating power supply of the vehicle 1000. The vehicle 1000 can further include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the working power demand of the vehicle 1000 during starting, navigation, and driving.

[0117] In some embodiments of the present application, the battery 100 can not only be used as an operating power supply of the vehicle 1000, but also be used as a driving power supply of the vehicle 1000, to replace or partially replace fuel or natural gas to provide driving power for the vehicle 1000. Referring to FIG. 2, an embodiment of the present application provides a battery 100. Referring to FIG. 2, the battery monomer 20 includes a box body 10 and one or more battery monomers 20 arranged in the box body 10.

[0118] The box body 10 is used to provide an accommodation space for the battery monomer 20. The box body 10 can adopt various structures. In some embodiments, the box body 10 can include a first part 11 and a second part 12. The first part 11 and the second part 12 are mutually covered, and the first part 11 and the second part 12 jointly define an accommodation space for accommodating the battery monomer 20. The second part 12 can be a hollow structure with one end open. The first part 11 can be a plate-shaped structure, and the first part 11 covers the open side of the second part 12 to jointly define the accommodation space with the second part 12. The first part 11 and the second part 12 can also be hollow structures with one side open, and the open side of the first part 11 covers the open side of the second part 12. Of course, the box body 10 formed by the first part 11 and the second part 12 can have various shapes, such as a cylinder, a cuboid, and the like.

[0119] In the battery 100, the battery cells 20 can be multiple, and the multiple battery cells 20 can be connected in series, in parallel, or in a mixed manner. The mixed manner means that the multiple battery cells 20 are connected in series and in parallel. The multiple battery cells 20 can be directly connected in series, in parallel, or in a mixed manner, and the whole of the multiple battery cells 20 is accommodated in the case 10. Of course, the battery 100 can also be that the multiple battery cells 20 are connected in series, in parallel, or in a mixed manner to form a battery module, and the multiple battery modules are connected in series, in parallel, or in a mixed manner to form a whole, and the whole is accommodated in the case 10. The battery 100 can also include other structures, for example, the battery 100 can also include a current collecting component for realizing the electrical connection between the multiple battery cells 20.

[0120] Each battery cell 20 can be a secondary battery or a primary battery, and can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto.

[0121] Please refer to FIG. 3, which is an exploded structural schematic diagram of the battery cell 20 provided by some embodiments of the present application. The battery cell 20 refers to the smallest unit that constitutes a battery. Referring to FIG. 3, the battery cell 20 includes an end cover 21, a shell 22, and a cell assembly 23.

[0122] The end cover 21 refers to a component that covers the opening of the shell 22 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cover 21 can be adapted to the shape of the shell 22 to fit the shell 22. Optionally, the end cover 21 can be made of a material with certain hardness and strength (such as aluminum alloy), so that the end cover 21 is not easy to deform when subjected to extrusion and collision, so that the battery cell 20 can have higher structural strength, and the safety performance can also be improved. The end cover 21 can be provided with functional components such as an electrode terminal 21a. The electrode terminal 21a can be used for electrical connection with the cell assembly 23 for output or input of the electrical energy of the battery cell 20. In some embodiments, the end cover 21 can also be provided with a pressure relief mechanism for relieving the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold value. The material of the end cover 21 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not make special limitations thereon.

[0123] The shell 22 is a component for cooperating with the end cover 21 to form an internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 23, electrolyte and other components. The shell 22 and the end cover 21 can be independent components, and an opening can be provided on the shell 22, and the end cover 21 is used to cover the opening to form the internal environment of the battery cell 20. Without limitation, the end cover 21 and the shell 22 can also be integrated, specifically, the end cover 21 and the shell 22 can form a common connecting surface before other components enter the shell, and when it is necessary to seal the internal environment of the shell 22, the end cover 21 is used to cover the shell 22. The shell 22 can be various shapes and sizes, such as a cuboid, a cylinder, a hexagonal prism, etc. Specifically, the shape of the shell 22 can be determined according to the specific shape and size of the electrode assembly 23. The material of the shell 22 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not make special limitations.

[0124] The electrode assembly 23 is a component in which electrochemical reactions occur in the battery cell 2000, and is a basic unit capable of realizing mutual conversion between chemical energy and electrical energy. One or more electrode assemblies 23 can be contained in the shell 22. The electrode assembly 23 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet and the negative electrode sheet have a portion with active material constituting a main body of the electrode assembly, and a portion without active material of the positive electrode sheet and the negative electrode sheet respectively constitutes a tab 23a. The positive electrode tab and the negative electrode tab can be located at one end of the main body or at two ends of the main body respectively. In the charging and discharging process of the battery, the positive active material and the negative active material react with the electrolyte, and the tab 23a is connected to the electrode terminal 21a to form a current loop.

[0125] Please refer to FIG. 4, FIG. 5 and FIG. 6, the battery cell 20 further comprises an electrode terminal 21a and a rubber seal 25. The electrode terminal 21a is provided on the end cover 21 and is used to connect with the electrode assembly 23. The rubber seal 25 is provided between the electrode terminal 21a and the end cover 21. The rubber seal 25 not only has a sealing effect, but also has an insulating effect, avoiding conduction between the electrode terminal 21a and the end cover 21.

[0126] Further, the end cover 21 is provided with a mounting hole 231, and the electrode terminal 21a is provided on the end cover 21 through the mounting hole 231 and connected with the electrode assembly 23 inside the shell 22.

[0127] The rubber seal 25 comprises hydrogenated nitrile rubber (HNBR) and ethylene propylene diene rubber (EPDM), and the weight average molecular weight of the hydrogenated nitrile rubber is 100,000-1,000,000. Further, the rubber seal 25 comprises a co-vulcanizate of hydrogenated nitrile rubber (HNBR) and ethylene propylene diene rubber (EPDM). The characteristic functional groups and absorption peaks of the co-vulcanizate in the rubber seal 25 can be detected by infrared spectroscopy, including carbon-hydrogen bond (C-H), carbon-carbon double bond (C=C) and cyano functional group (C≡N), and the chemical shifts of hydrogen atoms in different chemical environments can be observed by combining with nuclear magnetic resonance hydrogen spectrum, so as to verify the existence of different functional groups or structural units on the rubber molecular chain, thereby the components of the rubber seal 25 or the rubber components forming the rubber seal 25 or the co-vulcanizate can be inferred. The content of fillers and other inorganic substances in the rubber can also be analyzed by combining with thermogravimetric analysis and ash detection to obtain the main component composition of the rubber seal 25.

[0128] Please continue to refer to FIG. 5, in the specific example, the rubber seal 25 is a sealing ring. Understandably, the electrode terminal 21a is arranged on the outer side of the end cover 21.

[0129] The hydrogenated nitrile rubber (HNBR) is a highly saturated elastomer material prepared by selectively hydrogenating the butadiene carbon-carbon double bond in nitrile rubber (NBR). Specifically, the HNBR has excellent high and low temperature resistance, chemical stability and compression resistance due to the presence of cyano groups, and has excellent heat-oxygen aging resistance due to the reduction of double bonds after hydrogenation. The excellent comprehensive performance makes the application of HNBR in the key sealing material of the battery be valued, but the presence of strong polar side groups needs to be improved.

[0130] The hydrogenated nitrile rubber (HNBR) with a specific weight average molecular weight used in the present application is solid at room temperature and normal pressure. The molecular weight of the hydrogenated nitrile rubber is less than 100,000, which is generally liquid hydrogenated nitrile rubber. Compared with solid hydrogenated nitrile rubber, liquid hydrogenated nitrile rubber has high price, poor strength and poor flex resistance, so the tensile strength of the prepared sealing material is very low, and the electrolyte swelling resistance and compression resistance are poor, which is difficult to meet the use requirements of the sealing material.

[0131] The higher the molecular weight of the hydrogenated nitrile rubber, the worse the flowability, and the more difficult the processing. It is difficult to produce rubber with a molecular weight greater than 1,000,000, and the equipment requirements are also relatively harsh; in addition, the hydrogenation efficiency is slow and the cost is also higher. Therefore, the weight average molecular weight of the hydrogenated nitrile rubber is controlled to be 100,000-1,000,000.

[0132] The main chain of ethylene propylene diene rubber (EPDM) has a stable saturated structure, side groups contain a large number of double bonds and do not contain polar groups, thus having good weather resistance, ozone resistance and chemical resistance, and as a battery sealing material, it has excellent electrolyte swelling resistance. However, due to the lack of active groups in the molecular structure of EPDM, the cohesive energy is low, and the intermolecular force is weak, resulting in poor compression resistance and high temperature resistance, low strength and general processing performance.

[0133] Therefore, in order to improve the sealing performance of the battery monomer and the service life of the battery and the battery monomer, the rubber sealing element applied to the battery monomer of the application comprises hydrogenated nitrile rubber (HNBR) and ethylene propylene diene rubber (EPDM) with a specific weight average molecular weight.

[0134] Among them, the hydrogenated nitrile rubber (HNBR) is a strong polar tensile crystalline rubber, and the EPDM is a non-polar rubber. Since the polarity of HNBR and EPDM is quite different, the compatibility of the two is poor, but the structure of the butadiene saturated structure in HNBR is similar to that of the ethylene propylene segment, so even without adding a compatibilizer, it can be well co-vulcanized, so the preparation raw material of the rubber sealing element in the application can not add a compatibilizer, and the compatibilizer is optionally added.

[0135] Therefore, the rubber sealing element prepared by compounding the hydrogenated nitrile rubber (HNBR) with a specific weight average molecular weight and the ethylene propylene diene rubber (EPDM) has good high and low temperature resistance, insulation performance and chemical resistance, especially electrolyte swelling resistance. In addition, it can obtain better compression resistance, so it can provide good sealing performance, which can improve the service life of the battery and the battery monomer.

[0136] In some embodiments of the application, the acrylonitrile content of the hydrogenated nitrile rubber is 15wt% to 45wt%. As an example, the acrylonitrile content of the hydrogenated nitrile rubber can be 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, or within a range formed by any two of the above. The higher the acrylonitrile content of the hydrogenated nitrile rubber, the higher the tensile strength, heat resistance, oil resistance, air tightness and hardness, but the low temperature resistance is reduced, so further controlling the acrylonitrile content of the hydrogenated nitrile rubber within the range can make the prepared rubber sealing element have better high and low temperature resistance, insulation performance and chemical resistance, especially electrolyte swelling resistance. Understandably, the acrylonitrile content of the hydrogenated nitrile rubber refers to the content of the acrylonitrile unit in the hydrogenated nitrile rubber.

[0137] In some embodiments of the present application, the hydrogenated nitrile rubber has a hydrogenation degree of ≥ 80%. The hydrogenation degree of the hydrogenated nitrile rubber in this range can have better heat resistance, low temperature resistance, ozone resistance, chemical resistance and mechanical strength. For example, the hydrogenation degree of the hydrogenated nitrile rubber can be 80%, 85%, 90%, 95%, 99%, 100%, or within a range defined by any two of the above values, optionally ≥ 90%.

[0138] In some embodiments of the present application, the ethylene content in the EPDM rubber is 55wt% to 70wt%, for example, the ethylene content can be 55wt%, 56wt%, 57.5wt%, 60wt%, 65wt%, 70wt%, or within a range defined by any two of the above values. Higher ethylene content can enhance the intermolecular force in the rubber compound, significantly improve the mechanical properties such as tensile strength and elongation at break, and improve the mechanical strength and wear resistance of the seal, thereby prolonging the service life. Understandably, the ethylene content of the hydrogenated nitrile rubber refers to the content of ethylene units in the hydrogenated nitrile rubber.

[0139] In some embodiments of the present application, the third monomer content in the EPDM rubber is 2wt% to 8wt%, further 3wt% to 8wt%, for example, it can be 2wt%, 3wt%, 3.4wt%, 3.8wt%, 4wt%, 4.5wt%, 5wt%, 6wt%, 7wt% or 8wt%, or within a range defined by any two of the above values; further 3wt% to 4.5wt%. The third monomer includes non-conjugated diene, which includes but is not limited to at least one of ethylidene norbornene (ENB) and dicyclopentadiene (DCPD). In an example, the third monomer is ethylidene norbornene (ENB). The higher the third monomer content, the higher the content of vulcanizable double bonds in the rubber, the faster the vulcanization rate, and the mechanical strength of the vulcanized rubber increases, but the heat resistance decreases. When blending with hydrogenated nitrile rubber, selecting EPDM rubber with moderate third monomer content is more conducive to adjusting the vulcanization characteristics, and can better achieve co-vulcanization of the two rubbers, increase the intermolecular force, and thus improve the comprehensive performance of the vulcanized rubber. The third monomer content in the above range can improve the electrolyte swelling resistance and compression resistance of the rubber seal. Understandably, the third monomer content of the hydrogenated nitrile rubber refers to the content of third monomer units in the hydrogenated nitrile rubber.

[0140] In some embodiments of the present application, the Mooney viscosity ML (1+4) 100°C of the EPDM rubber is 20-80, for example, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or a range between any two of the aforementioned values; further, 20-40. M represents Mooney, L represents large rotor. 1 represents preheating for 1 minute, 4 represents testing for 4 minutes. 100°C - testing temperature is 100°C. The larger the Mooney value, the greater the viscosity, the lower the plasticity, which is widely used as an indicator for controlling the process performance of rubber compounds.

[0141] The Mooney viscosity has a great influence on the curing properties of the EPDM rubber. The larger the value, the faster the curing speed, the stronger the intermolecular force, and to some extent, the mechanical properties such as hardness, tensile strength and elongation at break can be improved. However, the rubber with large viscosity has poor flowability, and the filler and additives are not easy to disperse. When blended with hydrogenated nitrile rubber, the processing is difficult. Therefore, the use of the above-mentioned EPDM rubber with lower Mooney viscosity has excellent processing performance and saves energy consumption, and at the same time, it can help the reinforcing filler in the raw materials for the preparation of the rubber seal to be uniformly dispersed in the rubber seal, without the need for any other softening agent, so that a relatively soft and stable performance of the rubber seal can be obtained.

[0142] In some embodiments, the raw materials for the preparation of the rubber seal 25 include the above-mentioned hydrogenated nitrile rubber, EPDM rubber, and one or more of reinforcing fillers, insulating fillers, processing aids, vulcanizing agents, vulcanizing activators and vulcanizing aids.

[0143] Further, the rubber seal 25 includes the above-mentioned hydrogenated nitrile rubber, EPDM rubber, and one or more of reinforcing fillers, insulating fillers and processing aids.

[0144] Further, the rubber seal 25 includes the above-mentioned hydrogenated nitrile rubber, EPDM rubber, and one or more of reinforcing fillers, insulating fillers and processing aids.

[0145] Further, the raw materials for the preparation of the rubber seal 25 include the above-mentioned hydrogenated nitrile rubber, EPDM rubber, and reinforcing fillers, insulating fillers, processing aids, vulcanizing agents, vulcanizing activators and vulcanizing aids.

[0146] Further, in the rubber seal 25, the hydrogenated nitrile rubber is 100 parts by weight, and optionally, the reinforcing fillers are 30-70 parts by weight, and optionally, the insulating fillers are 10-30 parts by weight, and optionally, the processing aids are 4-12 parts by weight, and optionally, the vulcanizing agents are 4-12 parts by weight, and optionally, the vulcanizing activators are 2-10 parts by weight, and optionally, the vulcanizing aids are 0.5-4 parts by weight, and optionally, the compatibilizers are 0-20 parts by weight.

[0147] The rubber seal adopts hydrogenated nitrile rubber (HNBR) with a specific weight average molecular weight and is combined with ethylene propylene terpolymer, reinforcing filler, insulating filler, processing aid, vulcanizing agent, vulcanizing activator and vulcanizing aid. Properly increasing the weight average molecular weight of HNBR can improve the physical and mechanical properties of the rubber such as tensile strength and wear resistance, and the rubber seal has good heat resistance and aging resistance. However, HNBR with a high weight average molecular weight usually has a large viscosity, and higher energy is required to slow down the vulcanization speed during processing, which can adversely affect the performance of the vulcanized rubber seal. Therefore, by using the above preparation raw materials and controlling the weight average molecular weight within the above range, the processing performance of the HNBR rubber product can be improved, and the rubber seal prepared has good low temperature resistance, insulation performance, compression resistance and chemical resistance, especially electrolyte swelling resistance. In addition, the rubber seal also has good mechanical properties and high temperature resistance, thereby improving the service life of the rubber seal, the battery and the battery cell.

[0148] In some embodiments, the preparation raw materials include 100 parts of hydrogenated nitrile rubber, 10-40 parts of ethylene propylene terpolymer, and 4-12 parts of vulcanizing agent by weight.

[0149] In some embodiments, the preparation raw materials of the rubber seal further include one or more of reinforcing filler, insulating filler, processing aid, vulcanizing activator and vulcanizing aid. Further, the preparation raw materials of the rubber seal further include reinforcing filler, insulating filler, processing aid, vulcanizing activator and vulcanizing aid. Further, the preparation raw materials of the rubber seal can optionally include a compatibilizer.

[0150] In some embodiments, the preparation raw materials include 100 parts of hydrogenated nitrile rubber, 10-40 parts of ethylene propylene terpolymer, 30-70 parts of reinforcing filler, 10-30 parts of insulating filler, 4-12 parts of processing aid, 4-12 parts of vulcanizing agent, 2-10 parts of vulcanizing activator and 0.5-4 parts of vulcanizing aid by weight, and further include 0-20 parts of compatibilizer. The weight average molecular weight of the hydrogenated nitrile rubber is 100-1000. Controlling the above preparation raw materials within the above range can improve the processing performance of the HNBR rubber product, and the rubber seal prepared has further improved compression resistance and elongation at break under the conditions of good low temperature resistance, insulation performance and electrolyte swelling resistance, thereby improving the service life of the rubber seal, the battery and the battery cell.

[0151] For example, the weight average molecular weight of the hydrogenated nitrile rubber can be 100,000, 150,000, 200,000, 220,000, 250,000, 270,000, 280,000, 300,000, 330,000, 350,000, 370,000, 400,000, 430,000, 450,000, 500,000, 550,000, 600,000, 650,000, 700,000, 750,000, 800,000, 850,000, 900,000, 950,000, 1,000,000, or a range between any two of the above values.

[0152] In some embodiments of the present application, the weight average molecular weight of the hydrogenated nitrile rubber is in a range of 100,000 to 700,000, or in a range of 200,000 to 600,000, or in a range of 200,000 to 450,000, or a range between any two of the above values as the end value.

[0153] The weight average molecular weight of the hydrogenated nitrile rubber in the range can further improve the elongation at break and chemical resistance, especially the electrolyte swelling resistance of the prepared rubber seal, and further improve the service life of the battery and the battery cell, on the basis of good low temperature resistance and insulation performance.

[0154] For example, in the above preparation raw materials, the weight percentage of the hydrogenated nitrile rubber is 100 parts, and the reinforcing filler can be 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, or a range between any two of the above values; optionally, 50 to 60 parts. Further, the reinforcing filler includes at least one of carbon black, white carbon black, calcium carbonate, talc powder, mica powder and montmorillonite.

[0155] In a specific example, the reinforcing filler can be carbon black.

[0156] In another specific example, the reinforcing filler includes carbon black and calcium carbonate, or carbon black and white carbon black; further, the mass ratio of carbon black and calcium carbonate or the mass ratio of carbon black and white carbon black is (2 to 6):1, for example, 2:1, 3:1, 4:1, 5:1, 6:1. The addition of white carbon black can improve the insulation performance and elongation at break, so that the prepared rubber seal has higher volume resistivity and elongation at break, and can provide better insulation performance and longer service life.

[0157] For example, in the above preparation raw materials, the weight percentage of the hydrogenated nitrile rubber is 100 parts, and the insulating filler can be 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, or a range between any two of the above values; optionally, 20 to 30 parts. Further, the insulating filler includes at least one of barium sulfate and kaolin.

[0158] In a specific example, the insulating filler can be kaolin or barium sulfate.

[0159] In another specific example, the insulating filler comprises kaolin and barium sulfate; further, the mass ratio of the kaolin and the barium sulfate is 1:(0.8-1.2), for example, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2. The use of the compounded insulating filler can improve the insulating performance of the rubber seal.

[0160] For example, in the above preparation raw materials, the hydrogenated nitrile rubber is 100 parts, and the processing aid can be 4 parts, 5 parts, 6 parts, 8 parts, 10 parts, 12 parts, or a range formed by any two of the above point values; optionally, 6-8 parts. Further, the processing aid comprises at least one of a fatty acid derivative and an organic acid ester compound.

[0161] Further, the fatty acid derivative comprises at least one of stearic acid, zinc stearate, magnesium stearate, calcium stearate, potassium stearate, and sodium stearate. The fatty acid derivative can act as a lubricant and a plasticizer.

[0162] Further, the organic acid ester compound comprises at least one of trioctyl trimellitate, diisononyl phthalate, and dioctyl sebacate. The fatty acid derivative can act as a plasticizer.

[0163] In some embodiments, the above preparation raw materials can further comprise liquid hydrogenated nitrile rubber, which can act as a plasticizer. It should be noted that the weight average molecular weight of the liquid hydrogenated nitrile rubber is <100,000.

[0164] In a specific example, the processing aid comprises an organic acid ester compound and a fatty acid derivative, which are compounded to further improve the processing performance, and thus the mechanical performance of the prepared seal; further, the processing aid comprises dioctyl sebacate and stearic acid. Further, the mass ratio of the organic acid ester compound and the fatty acid derivative is (2-5):1; further, the mass ratio can be 2:1, 3:1, 4:1, 5:1.

[0165] For example, in the above preparation raw materials, the hydrogenated nitrile rubber is 100 parts, and the vulcanizing agent can be 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, or a range formed by any two of the above point values; optionally, 6-8 parts. Further, the vulcanizing agent comprises a peroxide vulcanizing agent, a sulfur vulcanizing agent, and a metal oxide vulcanizing agent.

[0166] Further, the peroxide vulcanizing agent comprises at least one of dicumyl peroxide (DCP), di(tert-butylperoxy isopropyl) benzene (BIPB), and 2,5-dimethyl-2,5-bis(tert-butylperoxy) hexane.

[0167] As an example, in the above preparation raw materials, the hydrogenated nitrile rubber is 100 parts by weight, and the vulcanization activator can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, or a range formed by any two of the above point values; optionally 4-6 parts.

[0168] Further, the vulcanization activator includes a metal oxide vulcanization activator. Further, the metal oxide vulcanization activator includes at least one of zinc oxide and magnesium oxide. The metal oxide in the vulcanization activator can promote the chemical reaction between the rubber molecular chain and the vulcanizing agent by forming a complex, helping to generate crosslinking bonds and form a stable network structure. Not only can it increase the crosslinking density of the rubber to a certain extent, but also can improve the processing performance of the rubber and improve the dimensional stability of the rubber product.

[0169] Further, the metal oxide in the vulcanization activator includes both zinc oxide and magnesium oxide; further, the mass ratio of zinc oxide to magnesium oxide is (1-2):1, as an example, it can be 1:1, 1.1:1, 8:7, 1.2:1, 1.3:1, 4:3, 1.4:1, 1.5:1, 1.6:1, 5:3, 1.7:1, 1.8:1, 2:1, or a range formed by any two of the above point values.

[0170] As an example, in the above preparation raw materials, the hydrogenated nitrile rubber is 100 parts by weight, and the vulcanization activator can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, or a range formed by any two of the above point values; optionally 4-6 parts.

[0171] Further, the vulcanization activator includes a metal oxide vulcanization activator. Further, the metal oxide vulcanization activator includes at least one of zinc oxide and magnesium oxide. The metal oxide in the vulcanization activator can promote the chemical reaction between the rubber molecular chain and the vulcanizing agent by forming a complex, helping to generate crosslinking bonds and form a stable network structure. Not only can it increase the crosslinking density of the rubber to a certain extent, but also can improve the processing performance of the rubber and improve the dimensional stability of the rubber product.

[0172] As an example, in the above preparation raw materials, the hydrogenated nitrile rubber is 100 parts by weight, and the compatibilizer can be 0 parts, 1 part, 2 parts, 3 parts, 5 parts, 8 parts, 9 parts, 10 parts, 12 parts, 15 parts, 16 parts, 18 parts, 20 parts, or a range formed by any two of the above points; optionally 5-20 parts, and further optionally 5-10 parts. Further, the compatibilizer includes at least one of chlorinated polyethylene (CPE) and chlorosulfonated polyethylene, and is optionally chlorinated polyethylene (CPE). Because the polarity of HNBR and EPDM is quite different, the compatibility is poor during mixing and processing, but the structure of the butadiene saturated structure in HNBR and the structure of the ethylene-propylene segment are similar, so the compatibility of HNBR and EPDM can be improved by adding a compatibilizer and optimizing the formulation system. The compatibilizer can help adjust the vulcanization rate between the rubber components, further promote the mixing of hydrogenated nitrile rubber (HNBR) and ethylene-propylene-diene rubber (EPDM), and thus enable better co-vulcanization. In addition, the compatibilizer can also improve the stability of the dispersed phase, reduce the aggregation of the dispersed phase, improve the mixing and processing performance, and thus improve the strength, aging resistance, and heat resistance of the rubber seal.

[0173] In some embodiments of the present application, in the above preparation raw materials, the hydrogenated nitrile rubber is 100 parts by weight, the ethylene-propylene-diene rubber is 20-30 parts, the reinforcing filler is 50-60 parts, the insulating filler is 20-30 parts, the processing aid is 6-8 parts, the vulcanizing agent is 6-8 parts, the vulcanizing activator is 5-10 parts, the vulcanizing aid is 2-3 parts, and the compatibilizer is 5-20 parts. Controlling the components of the above preparation raw materials within this range can further improve the electrolyte swelling resistance, compression resistance, tensile strength, and elongation at break of the hydrogenated nitrile rubber sealing material, and further improve the service life of the battery and battery cell, while maintaining good low-temperature resistance and insulation performance.

[0174] The rubber seal prepared from the above preparation raw materials has good high and low temperature resistance, insulation performance, and chemical resistance, especially electrolyte swelling resistance, in addition to good mechanical properties, high temperature resistance, and compression resistance.

[0175] The present application also provides a raw material composition for preparing a rubber seal, which includes hydrogenated nitrile rubber, ethylene-propylene-diene rubber, and a vulcanizing agent. Further, it also includes a reinforcing filler, an insulating filler, a processing aid, a vulcanizing activator, and a vulcanizing aid. Further, it can also optionally include a compatibilizer. Further, the weight fractions of the above raw materials are as described above and will not be repeated here.

[0176] In addition, an embodiment of the present application also provides a preparation method of the above rubber seal, which includes the following steps S10-S20:

[0177] S10, mixing the raw materials to obtain a rubber compound.

[0178] In some embodiments, step S10 comprises steps S11-S12.

[0179] S11, plasticizing the hydrogenated nitrile rubber and the ethylene propylene diene rubber, and then mixing the optional compatibilizer, the reinforcing filler, the insulating filler, the processing aid, and the vulcanization activator.

[0180] Further, the temperature of the mixing in S11 is 50-100°C, and the time is 5-10 minutes. As an example, the temperature of the mixing in S11 can be 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, and the time can be 5 minutes, 6 minutes, 6.5 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, or a range formed by any two of the above values as the end values.

[0181] S12, then mixing the vulcanizing agent and the optional vulcanizing aid in sequence to obtain a rubber compound containing hydrogenated nitrile rubber, and cooling.

[0182] Further, the temperature of the mixing in S12 is 50-100°C, and the time is 5-10 minutes. As an example, the temperature of the mixing in S12 can be 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, and the time can be 5 minutes, 6 minutes, 6.5 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, or a range formed by any two of the above values as the end values.

[0183] Further, the cooling step comprises placing at 23±2°C for 8-24 hours.

[0184] S20, vulcanizing the rubber compound to obtain a rubber seal.

[0185] In some embodiments, the temperature of the vulcanization in S20 is 140-200°C; as an example, the temperature can be 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, further 140-180°C, or a range formed by any two of the above values as the end values.

[0186] In some embodiments, the pressure of the vulcanization in S20 is 8-20 MPa; as an example, the pressure is 8 MPa, 9 MPa, 10 MPa, 12 MPa, 14 MPa, 15 MPa, 16 MPa, 18 MPa, 20 MPa, or a range formed by any two of the above values as the end values.

[0187] In some embodiments, the vulcanization molding time in S20 is 1xT90~3xT90, for example, 1xT90, 1.5xT90, 2xT90, 2.5xT90, 3xT90. Wherein, T90 refers to the process curing time of the vulcanization system, specifically the time required for the torque to reach 90% of the maximum torque from the start of heating, which can be obtained from the vulcanization curve obtained by the vulcanization instrument.

[0188] Further, the vulcanization molding temperature is 160~180℃, the pressure is 10~15Mpa, and the time is (1.5~2.5)xT 90 within the range.

[0189] In some embodiments, the rubber seal can include but is not limited to a sealing ring, a sealing gasket, etc. The above vulcanization molding can be carried out in different molds according to the different shapes of the rubber seal.

[0190] The electrolyte solution swelling resistance refers to the ability of the material to resist volume expansion or mass increase after contacting the electrolyte, which can be characterized by mass change rate and / or volume expansion rate.

[0191] The mass change rate of the above rubber seal is <22% and the volume expansion rate is ≤25.5% when immersed in dimethyl carbonate solvent at 70℃. In some embodiments of the present application, the mass change rate of the above rubber seal is <20%, further ≤19%, and the volume expansion rate is ≤23%, further ≤22% when immersed in dimethyl carbonate solvent at 70℃.

[0192] The compression permanent set of the above rubber seal is ≤25%. In some embodiments of the present application, the compression permanent set of the above rubber seal is ≤24%, further ≤22%. The compression permanent set is an important indicator of the recovery ability of the material after compression. The compression permanent set refers to the ratio of the permanent deformation part to the original size after the material is compressed for a certain time at a specified temperature, time and compression rate, and then the pressure is removed. It is usually expressed in percentage. In the present application, the compression permanent set is tested according to the national standard GB / T 7759.1 after compression at 120℃ for 9 days.

[0193] The volume resistivity of the above rubber seal is >10x10 10 Ω·cm. The volume resistivity refers to the resistance between two faces of a cubic material with an edge length of 1 centimeter, usually expressed in ohm·centimeter (Ω·cm), which reflects the ability of the material to hinder the flow of current within it. In the present application, the volume resistivity is tested according to the national standard GBT 31838.2-2019 at a test voltage of 500V. Further, the volume resistivity is >50x10 10Ω·cm.

[0194] The tensile strength of the rubber seal is ≥15 MPa and the elongation at break is ≥150%, which can well meet the use requirements of the battery monomer. In some embodiments of the present application, the tensile strength of the rubber seal is ≥16.0 MPa, further, the tensile strength is ≥19.0 MPa and the elongation at break is ≥200%, which can better meet the use requirements of the battery monomer and prolong the service life. The tensile strength is the maximum stress that the material can withstand in the tensile test; the elongation at break is the ratio of the elongation of the sample at break to the original length in the tensile test, which is usually expressed in percentage. In the present application, the tensile strength and the elongation at break are tested according to the provisions of GB / T 5720-2008.

[0195] In some embodiments of the present application, the low temperature brittleness temperature (i.e. ductile-brittle transition temperature) of the rubber seal can be as low as -54.5℃, which has excellent low temperature resistance and also has good high temperature resistance, and can be used for a long time at -40℃-120℃. Further, it can be used for a long time at -55℃-120℃. The low temperature brittleness temperature of the rubber seal is between -54.5℃ and -49℃; further, the low temperature brittleness temperature of the rubber seal is between -54.5℃ and -49.2℃.

[0196] The low temperature brittleness temperature in the present application can be tested according to the provisions of GB / T 1682-2014.

[0197] In addition, the rubber seal has a suitable hardness, and the Shore A hardness is 65-85; within this hardness range, it has good wear resistance, is not easy to deform, and has good processing performance and sealing performance, which is beneficial to improve the service life and sealing performance. In some embodiments, the Shore A hardness of the rubber seal is 65-76, and further can be 70-76.

[0198] The shape of the battery monomer 20 is not particularly limited in the present application, and it can be a cylinder, a flat body, a cuboid or any other shape. For example, the battery monomer 20 shown in FIG. 3 is a cuboid structure as an example. Referring to FIG. 3, the shell 22 can include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a containing cavity. The opening of the shell 22 communicates with the containing cavity, and the end cover 21 can be provided on the opening to close the containing cavity. The cell assembly 23 is packaged in the containing cavity.

[0199] The number of cell assemblies 23 contained in the battery monomer 20 can be one or more, which can be selected by those skilled in the art according to the specific actual needs.

[0200] In some embodiments, the electrode assembly 23 includes a positive electrode sheet, a separator, and a negative electrode sheet stacked in a stack, and the electrode assembly 23 can be formed by a winding process or a stacking process. The battery cell 20 further includes an electrolyte disposed in the case 22 and impregnated in the electrode assembly 23.

[0201] Positive electrode sheet

[0202] The positive electrode sheet includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, the positive electrode film layer including a positive electrode active material.

[0203] As a non-limiting example, the positive electrode current collector has two surfaces opposite in a thickness direction thereof, and the positive electrode active material layer is disposed on either one or both of the two surfaces of the positive electrode current collector.

[0204] In some embodiments, the positive electrode current collector can be a metal foil or a composite current collector. For example, as the metal foil, an aluminum foil can be used. The composite current collector can include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector can be obtained by forming a metal material on a polymer material base material. Non-limiting examples of the metal material in the positive electrode current collector can include one or more of aluminum, an aluminum alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, a silver alloy, and the like. Non-limiting examples of the polymer material base material in the positive electrode current collector can include one or more of a polypropylene (PP) base material, a polyethylene terephthalate (PET) base material, a polybutylene terephthalate (PBT) base material, a polystyrene (PS) base material, a polyethylene (PE) base material, and the like.

[0205] In some embodiments, the positive electrode active material can use a positive electrode active material for a battery known in the art. As a non-limiting example, the positive electrode active material can include one or more of a lithium-containing phosphate having an olivine structure, a lithium transition metal oxide, and a modified compound of each thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as a positive electrode active material for a battery can also be used. These positive electrode active materials can be used alone only one or in combination of two or more. Examples of the lithium transition metal oxide can include, but are not limited to, one or more of a lithium cobalt oxide (e.g., LiCoO2), a lithium nickel oxide, a lithium manganese oxide, a lithium nickel cobalt oxide, a lithium manganese cobalt oxide, a lithium nickel manganese oxide, a lithium nickel cobalt manganese oxide, a lithium nickel cobalt aluminum oxide, and a modified compound thereof. Non-limiting examples of the lithium-containing phosphate having an olivine structure can include, but are not limited to, one or more of lithium iron phosphate, a composite of lithium iron phosphate and carbon, lithium manganese phosphate, a composite of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite of lithium manganese iron phosphate and carbon.

[0206] Non-limiting examples of lithium cobalt oxides can include LiCoO2; non-limiting examples of lithium nickel oxides can include LiNiO2; non-limiting examples of lithium manganese oxides can include LiMnO2, LiMn2O4, and the like; non-limiting examples of lithium nickel cobalt manganese oxides can include LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(also can be referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2(also can be referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2(also can be referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2(also can be referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2(also can be referred to as NCM 811 ), and the like. Non-limiting examples of lithium nickel cobalt aluminum oxides can include LiNi 0.8 Co 0.15 Al 0.05 O2.

[0207] It can be understood that the battery will be accompanied by lithium (Li) deintercalation and consumption during charging and discharging, and the content of Li in the positive active material is different when the battery is discharged to different states. In the enumeration of the positive active material in the present application, the content of Li is the initial state of the material unless otherwise specified. When the positive active material is applied to the positive electrode sheet in the battery system, the content of Li in the positive active material contained in the sheet will usually change after charging and discharging cycles. Among them, the content of Li can be quantified by molar content, but is not limited thereto. As for "the content of Li is the initial state of the material", the initial state of the material refers to the state before being put into the positive electrode slurry. It can be understood that new materials obtained by proper modification on the basis of the listed positive active materials are also within the scope of positive active materials, and the foregoing proper modification refers to acceptable modification methods for positive active materials, and non-limiting examples include coating modification.

[0208] In the enumeration of the positive active material in the present application, the content of oxygen (O) is only the theoretical state value, and the release of oxygen from the lattice will cause the molar content of oxygen to change, and the actual content of O will fluctuate. Among them, the content of O can be quantified by molar content, but is not limited thereto.

[0209] In some embodiments, the positive electrode active material layer optionally further includes a binder. As non-limiting examples, the binder can include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylate resin.

[0210] In some embodiments, the positive electrode active material layer optionally further includes a conductive agent. As non-limiting examples, the conductive agent can include one or more of super P, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0211] In some embodiments, the positive electrode tab can be prepared by dispersing the above-mentioned components for preparing the positive electrode tab, such as the positive electrode active material, the conductive agent, the binder, and any other components, in a solvent to form a positive electrode slurry; coating the positive electrode slurry on at least one side surface of the positive electrode current collector; and subjecting the positive electrode current collector to a drying, cold-pressing, or other process to obtain the positive electrode tab. The solvent can be selected from, but is not limited to, any of the above-mentioned embodiments, such as N-methyl pyrrolidone (NMP). The positive electrode slurry can be coated on a single surface of the positive electrode current collector, or on both surfaces of the positive electrode current collector. The solid content of the positive electrode slurry can be 40 wt% to 80 wt%.

[0212] Negative electrode tab

[0213] The negative electrode tab includes a negative electrode current collector. Further, the negative electrode tab can further include a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, the negative electrode active material layer including a negative electrode active material.

[0214] As non-limiting examples, the negative electrode current collector has two surfaces opposite in the thickness direction of the negative electrode current collector, and the negative electrode active material layer is disposed on either one or both of the two opposite surfaces of the negative electrode current collector.

[0215] In some embodiments, the negative current collector can employ a metal foil or a composite current collector. For example, as a metal foil, a copper foil can be employed. The composite current collector can include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector can be obtained by forming a metal material on a polymer material base layer. Non-limiting examples of the metal material in the negative current collector can include one or more of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, and the like. Non-limiting examples of the polymer material base layer in the negative current collector can include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), and the like.

[0216] In some embodiments, the negative active material can employ a negative active material for a battery known in the art. As non-limiting examples, the negative active material can include one or more of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, and lithium titanate, and the like. The silicon-based material can include one or more of elemental silicon, silicon oxide compound, silicon-carbon composite, silicon-nitrogen composite, and silicon alloy. The tin-based material can include one or more of elemental tin, tin oxide compound, and tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a negative active material for a battery can also be used. The negative active material can be used alone or in combination of two or more.

[0217] In some embodiments, the negative active material layer can further optionally include a binder. The binder can include one or more of styrene butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0218] In some embodiments, the negative active material layer can further optionally include a conductive agent. The conductive agent can include one or more of super P, acetylene black, carbon black, ketjen black, carbon dot, carbon nanotube, graphene, and carbon nanofiber.

[0219] In some embodiments, the negative active material layer can further optionally include other auxiliary agents, such as a thickening agent (e.g., sodium carboxymethyl cellulose (CMC-Na)), and the like.

[0220] In some embodiments, the negative electrode sheet can be prepared by dispersing the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder, and any other components, in a solvent (a non-limiting example of the solvent is deionized water) to form a negative electrode slurry; coating the negative electrode slurry on at least one side surface of the negative electrode current collector; and drying, cold-pressing, or the like, to obtain the negative electrode sheet. The surface of the negative electrode current collector to which the negative electrode slurry is coated can be a single surface of the negative electrode current collector or both surfaces of the negative electrode current collector. The solid content of the negative electrode slurry can be 40 wt% to 60 wt%.

[0221] electrolyte

[0222] The electrolyte functions to conduct ions between the positive electrode sheet and the negative electrode sheet. The electrolyte is impregnated in the cell assembly 23. The electrolyte includes an electrolyte salt and a solvent. Since the solvent in the electrolyte is generally an organic solvent, and the seal is also an organic material, the seal is easily swollen in the electrolyte, which in turn affects the sealing performance of the seal. As described above, the HNBR seal material absorbs the electrolyte in the battery and swells after being used for a certain period of time, which in turn reduces the service life and the sealing performance of the seal material.

[0223] In some embodiments, the solvent includes at least one of an ether solvent, an ester solvent, and a sulfone solvent.

[0224] As an example, the ether solvent can include at least one of ethylene glycol dimethyl ether (DME), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (TRGDME), tetraethylene glycol dimethyl ether (TEGDME), and 1,3-dioxolane (DOL).

[0225] As an example, the ester solvent can include at least one of ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), fluoroethylene carbonate (FEC), methyl ethyl carbonate (EMC), dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), γ-butyrolactone (BL), 1,3-propane sultone (1,3-PS), methyl propionate (MP), methyl butyrate (MB), ethyl acetate (EA), ethyl propionate (EP), propyl propionate (PP), and ethyl butyrate (EB).

[0226] As an example, the sulfone solvent includes dimethyl sulfoxide (DMSO).

[0227] In some embodiments, the electrolyte salt includes at least one of a sodium salt, a lithium salt, and a potassium salt.

[0228] As an example, the sodium salt in the electrolyte salt can be selected from one or more of sodium perchlorate (NaClO4), sodium tetrafluoroborate (NaBF4), sodium hexafluorophosphate (NaPF6), sodium hexafluoroarsenate (NaAsF6), sodium trifluoroacetate (CF3COONa), sodium tetraphenylborate (NaB(C6H5)4), sodium trifluoromethylsulfonate (NaSO3CF3), sodium bis(fluorosulfonyl)imide (Na[(FSO2)2N]), or sodium bis(trifluoromethylsulfonyl)imide (Na[(CF3SO2)2N]).

[0229] As an example, the lithium salt in the electrolyte salt can be selected from one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), lithium trifluoromethylsulfonate (LiTFS), lithium difluoro(oxalato)borate (LiDFOB), lithium difluoro(oxalato)phosphate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluoro(dioxalato)phosphate (LiDFOP), and lithium tetrafluoro(oxalato)phosphate (LiTFOP).

[0230] In some embodiments, the electrolyte solution can further optionally include an additive. For example, the additive can include a negative electrode film-forming additive, a positive electrode film-forming additive, and can further include an additive capable of improving certain performance of the battery, such as an additive for improving overcharge performance of the battery, an additive for improving high-temperature or low-temperature performance of the battery, etc.

[0231] Separating film

[0232] In some embodiments, a separating film is further included in the battery. The separating film is disposed between the positive electrode tab and the negative electrode tab, and functions to separate.

[0233] In some embodiments, the material of the separating film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separating film can be a single-layer film or a multi-layer composite film. When the separating film is a multi-layer composite film, the materials of the respective layers can be the same or different.

[0234] When the separating film is a multi-layer composite film, the materials of the respective layers can be the same or different, and are not particularly limited.

[0235] In some embodiments, the thickness of the separating film is 6 μm to 40 μm, and can be selected to be 12 μm to 20 μm.

[0236] Another embodiment of the present application further provides a battery including one or more of the above-described battery cells.

[0237] The battery cell is the smallest unit to form a battery. A plurality of battery cells can be connected in series, in parallel, or in a hybrid manner. That is, one battery can include one or more battery cells, and the plurality of battery cells can be connected in series, in parallel, or in a hybrid manner. The hybrid manner means that the plurality of battery cells are connected in series and in parallel.

[0238] After the plurality of battery cells are connected to each other and arranged in a certain order, they can be directly accommodated in the box to form a battery. Alternatively, the plurality of battery cells can be first assembled into a battery module, and then the plurality of battery modules are connected to each other to form a whole, and finally the whole of the battery module is accommodated in the box to form a battery.

[0239] In some embodiments, the above-mentioned battery can be, but is not limited to, a lithium ion battery, a sodium ion battery.

[0240] In addition, an embodiment of the present application also provides a power utilization device including the above-mentioned battery provided by the present application. The battery can be used as a power supply of the power utilization device, or as an energy storage unit of the power utilization device. The power utilization device can include a mobile device, an electric vehicle, an electric train, a ship and a satellite, an energy storage system, etc., but is not limited thereto. The mobile device can be, for example, a mobile phone, a notebook computer, etc.; the electric vehicle can be, for example, a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc., but is not limited thereto.

[0241] As the power utilization device, the battery cell, the battery pack, or the battery module can be selected as the battery according to the use requirement thereof.

[0242] FIG. 6 is a power utilization device 2 as an example. The power utilization device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the requirement of high power and high energy density of the battery for the power utilization device, the battery pack or the battery module can be used as a power supply.

[0243] As another example of the device, it can be a mobile phone, a tablet computer, a notebook computer, etc. The device usually requires thinness, and the battery cell can be used as a power supply.

[0244] In order to make the purpose, technical solutions and advantages of the present application more concise and clear, the present application is described by the following specific embodiments, but the present application is not limited to these embodiments. The embodiments described below are only better embodiments of the present application, which can be used to describe the present application, and cannot be understood as a limitation on the scope of the present application. It should be noted that any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0245] To better illustrate the present application, the following further describes the present application in conjunction with examples. The following are specific examples.

[0246] Reagent information:

[0247] The weight average molecular weight of hydrogenated nitrile rubber 1 (HNBR1) is 30±3 million, the acrylonitrile content is 34%, and the hydrogenation degree is 99%.

[0248] The weight average molecular weight of hydrogenated nitrile rubber 2 (HNBR2) is 25±3 million, the acrylonitrile content is 43%, and the hydrogenation degree is 99%.

[0249] The weight average molecular weight of hydrogenated nitrile rubber 3 (HNBR3) is 40±3 million, the acrylonitrile content is 40%, and the hydrogenation degree is 99%.

[0250] The weight average molecular weight of hydrogenated nitrile rubber 4 (HNBR4) is 50±10 million, the acrylonitrile content is 21%, and the hydrogenation degree is 95%.

[0251] The weight average molecular weight of hydrogenated nitrile rubber 5 (HNBR5) is 100±10 million, the acrylonitrile content is 17%, and the hydrogenation degree is 99%.

[0252] The ethylene content, the third monomer ENB content, and the Mooney viscosity ML(1+4)100℃ of the ethylene propylene terpolymer 1 (EPDM1), the ethylene propylene terpolymer 2 (EPDM2), and the ethylene propylene terpolymer 3 (EPDM3) are shown in Table 3.

[0253] Example 1

[0254] The raw materials for preparing a rubber seal include the components shown in Table 1 in parts by weight.

[0255] The specific preparation method in this example is as follows:

[0256] (1) After starting the internal mixer, hydrogenated nitrile rubber (HNBR1), ethylene propylene terpolymer 1 (EPDM1), and a compatibilizer (CPE) are added for plasticizing work, and then a processing aid (stearic acid), a vulcanization activator (ZnO), an insulating filler (barium sulfate), and a reinforcing filler (carbon black) are added together and blended at 70℃ for 6 minutes and 30 seconds to discharge the rubber.

[0257] (2) After starting the internal mixer again, the rubber compound obtained in (1) is added, and then a vulcanizing agent (DCP) and a vulcanizing aid (TAIC) are added, and the rubber is blended at 70℃ for 7 minutes and then discharged. The rubber compound is then rolled into a triangle package using an open mill for 10 times to obtain a rubber compound, which is cooled at room temperature for at least 24 hours.

[0258] (3) The rubber seal (sealing ring) was obtained by vulcanizing the rubber compound obtained in step (2) in a vulcanizing machine, setting the vulcanizing temperature to 180°C, the pressure to 10 MPa, and the vulcanizing time to 2xT90. T90 refers to the process vulcanizing time of the vulcanizing system, specifically the time required for the torque to reach 90% of the maximum torque from the start of heating, which can be obtained from the vulcanizing curve obtained by a vulcanizing instrument.

[0259] The prepared rubber sealing ring was applied to a battery monomer. The battery monomer of the present embodiment, as shown in FIG. 1, includes a shell 22, an electrode assembly 23, and an end cover 21. The shell 22 has an opening 111, and the electrode assembly 23 is accommodated in the shell 22; the end cover 21 is sealingly arranged at the opening 111. Referring to FIGS. 3, 4, and 5, the battery monomer 20 further includes an electrode terminal 21a and a rubber sealing member 25. The electrode terminal 21a is arranged on the end cover 21 and is used to connect with the electrode assembly 23. The rubber sealing member 25 is sealingly arranged between the electrode terminal 21a and the end cover 21. The end cover 21 is provided with a mounting hole 231, and the electrode terminal 21a is arranged on the end cover 21 through the mounting hole 231 and connected with the electrode assembly 23 inside the shell 22. The battery monomer 20 further includes an electrolyte, which is arranged in the shell 22 and infiltrates in the electrode assembly 23. The composition of the electrolyte is that the electrolyte contains ethylene carbonate and methyl ethyl carbonate in a mass ratio of 3:7, and contains LiPF6 with a concentration of 1 mol / L.

[0260] Example 2

[0261] The raw materials for preparing the rubber sealing member include the components shown in Table 1 in parts by weight.

[0262] The specific preparation method in the present embodiment is as follows:

[0263] (1) After starting the internal mixer, hydrogenated nitrile rubber (HNBR1), ethylene propylene diene rubber 1 (EPDM1), and a compatibilizer (CPE) were added for plasticizing work, and then a processing aid (stearic acid), a vulcanizing activator (ZnO), an insulating filler (barium sulfate), and a reinforcing filler (carbon black) were added together and blended at 70°C for 6 minutes and 30 seconds to discharge the rubber compound.

[0264] (2) After starting the internal mixer again, the rubber compound obtained in (1) was added, and then a vulcanizing agent (DCP) and a vulcanizing aid (TAIC) were added, and the rubber compound was blended at 70°C for 7 minutes to discharge the rubber compound. The rubber compound was then rolled into a triangle package 10 times using an open mill to obtain a rubber compound, which was placed at room temperature for at least 24 hours.

[0265] (3) The rubber compound obtained in step (2) was vulcanized in a vulcanizing machine, setting the vulcanizing temperature to 180°C, the pressure to 10 MPa, and the vulcanizing time to 2xT90.

[0266] Examples 3 to 15

[0267] A rubber seal preparation material, by weight, includes the components shown in Table 1. The preparation material is substantially the same as Example 1, except that at least one of the types and proportions of the components of the preparation material is different, as shown in Table 1, by weight.

[0268] Examples 16 to 19

[0269] A rubber seal preparation material has the same composition and proportions as Example 9, except that the specific type of hydrogenated nitrile rubber in the preparation material is different (specifically, the weight average molecular weight, acrylonitrile content, and hydrogenation degree are different), as shown in Table 2.

[0270] Examples 20 to 22

[0271] A rubber seal preparation material has the same composition and proportions as Example 9, except that the specific type of ethylene-propylene-diene rubber (EPDM) in the preparation material is different (specifically, the ethylene content, third monomer ENB content, and Mooney viscosity ML(1+4)100℃ are different), as shown in Table 3.

[0272] Comparative Example 1

[0273] Comparative Example 1 is substantially the same as Example 1, except that the ethylene-propylene-diene rubber 1 (EPDM1) in Example 1 is omitted, and the content of the reinforcing filler is slightly different, as shown in Table 1.

[0274] Comparative Example 2

[0275] Comparative Example 2 is substantially the same as Example 1, except that the hydrogenated nitrile rubber in Example 1 is omitted, and the mass in Comparative Example 2 is increased so that the weight fraction is 100 parts.

[0276] Table 1

[0277] Table 2

[0278] Table 3

[0279] The following are performance tests and test methods. The test methods involved are as follows.

[0280] (1) Low temperature brittleness test: test according to the provisions of GB / T 1682-2014, using the vulcanized seal sample of each example. Put the sample into the lifting holder, freeze in the freezing medium to the specified time, lift the lifting holder, impact the sample with the impactor within the specified time, take out the sample, and after at least 30 seconds, bend the sample to 180° in the impact direction, and observe whether there is damage. Through repeated tests, the lowest temperature at which the sample is not damaged and the highest temperature at which the previous two or more samples are damaged are determined. When the difference between the two results is not more than 1℃, the highest temperature at which the sample is damaged is the brittleness temperature.

[0281] Parameter result acquisition standard: if none of the samples in a group is damaged at a certain temperature, the test result is that the sample is not damaged at that temperature. If two or more samples in a group are completely damaged, the test result is that the sample is damaged. If only one sample in a group is damaged, test three new intact samples again. If all three samples are not damaged, the test result is not damaged, otherwise the test result is damaged.

[0282] (2) Volume resistivity:

[0283] Test according to the provisions of GBT 31838.2-2019, the test voltage is specified as 10V, 100V, 500V, 1000V or 10000V, and the volume resistivity of the present application is selected as 500V as the measurement voltage.

[0284] The vulcanized rubber sample for measuring the resistivity of rubber is circular with a diameter of ≥100mm and a thickness of 1.0±0.5mm.

[0285] The determination of the resistivity of rubber generally requires the use of electrical testing instruments or meters, such as a resistance meter, a conductivity measuring instrument, etc.

[0286] Method for measuring the volume resistivity of rubber: take the rubber sample to be tested (three as a group), measure the thickness of the sample, put the sample into the resistance measuring instrument, input the thickness of the sample, read the resistivity value after the test is completed and record it.

[0287] (3) Resistance to electrolyte swelling:

[0288] Electrolyte is generally prepared by mixing raw materials such as high-purity organic solvent, electrolyte lithium salt (lithium hexafluorophosphate, LiPF6), and necessary additives in a certain proportion under certain conditions. The solvents in the electrolyte are commonly propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, etc.

[0289] Currently, dimethyl carbonate is used as the reagent for simulating electrolyte swelling behavior.

[0290] The prepared rubber seal was cut into 25mm*25mm*2mm samples (three) to measure the mass in air and in water before swelling. The samples were placed in separate reaction kettles containing 25mL of dimethyl carbonate solvent, one piece in each kettle, and placed in a 70°C oven for 72h. After cooling for 30min to room temperature, the mass in air and in water after swelling was measured.

[0291] The calculation method of mass change rate is:

[0292] The calculation method of volume expansion rate is:

[0293] In the formula:

[0294] m 11 - the mass in air before swelling;

[0295] m 12 - the mass in air after swelling;

[0296] m 21 - the mass in water before swelling;

[0297] m 22 - the mass in water after swelling.

[0298] (4) Tensile strength and elongation at break:

[0299] The test was carried out according to GB / T 5720-2008, and the sealing material was made into dumbbell-shaped samples using the same process conditions as in each example, and then tested on a tensile testing machine. Type 2 dumbbell-shaped tensile samples were used, with a thickness of 2mm±0.2mm and a tensile speed of 500mm / min±50mm / min.

[0300] Tensile strength is the maximum tensile stress during the tensile process of the sample to break, and elongation at break is the percentage elongation at the time of sample breakage, which reflects the tensile strength and plastic deformation capacity of the material, respectively.

[0301] Test method: the thickness of the tensile sample was measured using a thickness gauge (at least three for a group), and the median of the three values was recorded and input. The sample was symmetrically clamped on a tensile testing machine, and the testing machine was started for tensile testing. The sample was subjected to a constant tensile force, and the tensile test was continued until the material broke. After the test was completed, the tensile strength and elongation at break were read and recorded.

[0302] (5) Compression set:

[0303] The degree of compression set is used to determine the sealing performance of the elastomer seal.

[0304] The test was carried out according to GB / T 7759.1, and the sealing material was made into a B-type sample using the same process conditions as in each example, and the compression permanent set rate at 120°C for 9 days @ 15% was tested. The B-type sample was cylindrical with a diameter of 13 mm ± 5 mm and a height of 6.3 mm ± 0.3 mm, and the stopper height was 5.3 mm to 5.4 mm when the compression rate was 15%.

[0305] Compression permanent set rate is a measure of the proportion of the original size of a material that is reduced when it is subjected to compression. In the compression permanent set test of rubber materials, it defines the degree to which the sample should be compressed during the test. The smaller the compression permanent set rate, the better the compression resistance, i.e. the better the sealing performance of the elastomer seal.

[0306] Test method: The thickness of the sample block was measured using a thickness gauge, the sample block was placed in a compression device, the B-type 15% stopper was selected, and after compression it was placed in a 120°C constant temperature oven, and after 9 days it was removed, the sample was released, placed on a wooden board for 30 min, and then the thickness of the sample after compression was measured using a thickness gauge.

[0307] The compression permanent set calculation formula is as follows:

[0308] The compression permanent set calculation formula is as follows:

[0309] In the formula:

[0310] h0——original height of the sample, mm;

[0311] h1——height after compression recovery, mm;

[0312] h s ——stopper height, mm.

[0313] The performance test results of the sealing elements prepared in the above examples and comparative examples are as follows, and the results are shown in Table 4.

[0314] Table 4

[0315] Compared with the examples, the sealing material prepared by using a single hydrogenated nitrile rubber in Comparative Example 1 has poor electrolyte swelling resistance, with a mass change rate > 26% and a volume expansion rate > 29% when immersed in dimethyl carbonate at 70°C for 3 days.

[0316] Compared with the examples, the sealing material prepared by using a single EPDM in Comparative Example 2 has a larger compression permanent set rate > 30% under the condition of 120°C compression for 9 days, is prone to deformation, and has a shorter service life.

[0317] The sealing material prepared in the above examples is a sealing material based on co-vulcanization of hydrogenated nitrile rubber and ethylene-propylene-diene rubber, with low-temperature brittleness temperature between -47℃ and -52.8℃, excellent low-temperature resistance, good insulation performance (volume resistivity of the material is 10 x 10 10 Ω·cm or more), and good electrolyte swelling resistance, with mass change rate ≤22% and volume expansion rate ≤25.5% after immersion in dimethyl carbonate at 70℃ for 3 days. In addition, the tensile strength of the sealing material of the examples is ≥15 MPa, and the elongation at break is ≥150%, showing good mechanical properties; at the same time, the compression set rate obtained by testing under the condition of compression at 120℃ for 9 days is ≤25%, all between 19.9% and 25%, showing good compression set resistance. Therefore, the sealing material provided in the examples can meet the sealing and insulation requirements of lithium ion batteries, and the raw materials thereof do not contain fluorine elements, avoiding the use of fluorine-containing compounds and meeting the demand for non-fluorine rubber sealing materials required by lithium ion batteries and other batteries.

[0318] In combination with Table 1 and Table 4, in Examples 1-10, the only difference is that the proportions of the raw materials for preparing the rubber sealing member are different. Compared with Examples 1-4 and Examples 8-10, in Example 5, the content of the vulcanizing agent is less, and the volume expansion rate of the prepared rubber sealing member is larger; in Example 6, the content of the ethylene-propylene-diene rubber is more, and the compression set rate of the prepared rubber sealing member is larger; in Example 7, the content of the ethylene-propylene-diene rubber is less, and the volume expansion rate of the prepared rubber sealing member is larger, and the volume resistivity is smaller.

[0319] Compared with Examples 1-7, in Examples 8-10, the proportions of the raw materials are further controlled, so that the hardness, low-temperature resistance, insulation, electrolyte swelling resistance and compression resistance of the prepared rubber sealing member are better, and the tensile strength and elongation at break are further improved.

[0320] As can be seen by comparing Example 9 with Example 11, without adding compatibility, the two can also be well co-vulcanized, and by adding compatibility, the tensile strength of the rubber sealing member can be improved.

[0321] Compared with Example 9, Example 12 uses compounded insulation filler with higher volume resistivity, Example 13 uses compounded vulcanization activator with higher tensile strength, and Examples 14-15 use compounded reinforcing filler with higher tensile strength.

[0322] In combination with Table 2 and Table 4, as can be seen by comparing Example 9 with Examples 16-19, by controlling the weight average molecular weight of the hydrogenated nitrile rubber in the raw materials to be within the range of 200,000-450,000 within 2,000,000-10,000,000, the tensile strength, elongation at break and electrolyte swelling resistance of the sealing material of the hydrogenated nitrile rubber can be further improved.

[0323] From the comparison of Example 9, Examples 20-22 in combination with Table 3 and Table 4, it can be seen that in Example 9, the content of the third monomer in the EPDM rubber is controlled to be 3wt%-8wt% and the Mooney viscosity is 20-40, which has better electrolyte swelling resistance and compression resistance.

[0324] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above-mentioned embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present disclosure.

[0325] The above-mentioned embodiments only express several embodiments of the present application, the description is more specific and detailed, but it should not be understood as a limitation to the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of the patent protection of the present application should be subject to the appended claims, the description and the drawings can be used to explain the content of the claims.

Claims

1. A battery cell, comprising: a housing having an opening; a cell assembly housed in the housing; a terminal cover sealingly disposed in the opening; an electrode terminal disposed on the terminal cover and configured to connect with the cell assembly; and a rubber seal sealingly disposed between the electrode terminal and the terminal cover, the rubber seal comprising a hydrogenated nitrile rubber and an ethylene-propylene-diene rubber, the hydrogenated nitrile rubber having a weight average molecular weight of 100,000 to 1,000,000. At least one of the following conditions is satisfied: (1) the rubber seal comprises a co-vulcanizate of the hydrogenated nitrile rubber and the ethylene-propylene-diene rubber; (2) the hydrogenated nitrile rubber has an acrylonitrile content of 15 wt% to 45 wt%; (3) the hydrogenated nitrile rubber has a hydrogenation degree of 80% or more; and (4) the hydrogenated nitrile rubber has a weight average molecular weight of 200,000 to 450,000. At least one of the following conditions is satisfied: (1) the ethylene-propylene-diene rubber has an ethylene content of 55 wt% to 70 wt%; (2) the ethylene-propylene-diene rubber has a third monomer content of 3 wt% to 8 wt%; and (3) the ethylene-propylene-diene rubber has a Mooney viscosity ML (1+4) 100℃ of 20 to 80. In the rubber seal, the hydrogenated nitrile rubber is 100 parts by weight, and the ethylene-propylene-diene rubber is 10 to 40 parts by weight. The rubber seal further comprises one or more of a reinforcing filler, an insulating filler, and a processing aid. In the rubber seal, the hydrogenated nitrile rubber is 100 parts by weight, and the rubber seal further satisfies at least one of the following conditions: (1) the rubber seal further comprises a reinforcing filler of 30 to 70 parts by weight; (2) the rubber seal further comprises an insulating filler of 10 to 30 parts by weight; and (3) the rubber seal further comprises a processing aid of 4 to 12 parts by weight. At least one of the following conditions is satisfied: (1) the reinforcing filler comprises at least one of carbon black, white carbon black, calcium carbonate, talc, mica powder, and montmorillonite; (2) the insulating filler comprises at least one of barium sulfate and kaolin; and (3) the processing aid comprises at least one of a fatty acid derivative and an organic acid ester compound.

2. The battery cell of claim 1, wherein, At least one of the following conditions is satisfied: (1) the fatty acid derivative comprises at least one of stearic acid, zinc stearate, magnesium stearate, calcium stearate, potassium stearate, and sodium stearate; and (2) the organic acid ester compound comprises at least one of trioctyl trimellitate, diisononyl phthalate, and dioctyl sebacate. The rubber seal further comprises one or more of a vulcanizing agent, a vulcanizing activator, a vulcanizing aid, and a compatibilizer. In the rubber seal, the hydrogenated nitrile rubber is 100 parts by weight, and the rubber seal further satisfies at least one of the following conditions: (1) the rubber seal further comprises a vulcanizing agent of 4 to 12 parts by weight; and (2) the rubber seal further comprises a vulcanizing activator of 2 to 10 parts by weight. ​ ​ 3. The battery cell of any one of claims 1 to 2, wherein, ​ ​ ​ ​ 4. The battery cell of any one of claims 1 to 3, wherein, ​ 5. The battery cell of any one of claims 1 to 4, wherein, ​ 6. The battery cell of claim 5, wherein, ​ ​ ​ ​ 7. The battery cell of any one of claims 5-6, wherein, ​ ​ ​ ​ 8. The battery cell of claim 7, wherein, ​ ​ ​ 9. The battery cell of any one of claims 1 to 8, wherein, ​ 10. The battery cell of claim 9, wherein, ​ ​ ​ (3) the rubber sealing element further comprises 0.5-4 parts by weight of a coagulator; (4) the rubber sealing element further comprises 0-20 parts by weight of a compatibilizer.

11. The battery cell of any one of claims 1 to 10, wherein, The rubber sealing element comprises 100 parts by weight of the hydrogenated nitrile rubber, 10-40 parts by weight of the ethylene-propylene-diene rubber, 30-70 parts by weight of a reinforcing filler, 10-30 parts by weight of an insulating filler, 4-12 parts by weight of a processing aid, 4-12 parts by weight of a vulcanizing agent, 2-10 parts by weight of a vulcanizing activator, 0.5-4 parts by weight of a coagulator, and 0-20 parts by weight of a compatibilizer.

12. The battery cell of claim 11, wherein, The rubber sealing element comprises 100 parts by weight of the hydrogenated nitrile rubber, 20-30 parts by weight of the ethylene-propylene-diene rubber, 50-60 parts by weight of a reinforcing filler, 20-30 parts by weight of an insulating filler, 6-8 parts by weight of a processing aid, 6-8 parts by weight of a vulcanizing agent, 4-6 parts by weight of a vulcanizing activator, 2-3 parts by weight of a coagulator, and 5-20 parts by weight of a compatibilizer.

13. The battery cell of any one of claims 9 to 12, wherein, At least one of the following conditions is satisfied: (1) the vulcanizing agent comprises at least one of a peroxide vulcanizing agent, a sulfur vulcanizing agent, and a metal oxide vulcanizing agent; (2) the vulcanizing activator comprises a metal oxide vulcanizing activator; (3) the coagulator comprises at least one of zinc dimethacrylate, triallyl cyanurate, triallyl isocyanurate, and bismaleimide; (4) the compatibilizer comprises at least one of chlorinated polyethylene and chlorosulfonated polyethylene.

14. The battery cell of claim 13, wherein, At least one of the following conditions is satisfied: (1) the metal oxide vulcanizing activator comprises at least one of zinc oxide and magnesium oxide; (2) the peroxide vulcanizing agent comprises at least one of dicumyl peroxide, di(tert-butylperoxy isopropyl)benzene, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane.

15. The battery cell of any one of claims 1 to 14, wherein, At least one of the following conditions is satisfied: (1) the rubber sealing element has a mass change rate of 22% and a volume expansion rate of ≤25.5% after being immersed in dimethyl carbonate solvent at 70°C for 72h; (2) the rubber sealing element has a compression permanent set rate of ≤25% after being compressed at 120°C for 9 days according to the national standard GB / T 7759.1; (3) The volume resistivity of the rubber seal at a test voltage of 500 V is > 10 x 10 10 Ω-cm according to the national standard GBT 31838.2-2019. (4) The rubber seal has a volume resistivity > 10 x 10 10 Ω-cm at a test voltage of 500 V according to the national standard GBT 31838.2-2019. (5) The rubber (4) the rubber sealing element has a tensile strength of ≥15MPa and an elongation at break of ≥150%; (5) the rubber sealing element has a low-temperature brittleness temperature of between -54.5°C and -49°C; (6) the rubber sealing element has a Shore A hardness of 65-85.

16. The battery cell of any one of claims 1 to 15, wherein, At least one of the following conditions is satisfied: (1) the rubber sealing element has a mass change rate of <20% and a volume expansion rate of ≤23% after being immersed in dimethyl carbonate solvent at 70°C for 72h; (2) the rubber sealing element has a compression permanent set rate of ≤24% after being compressed at 120°C for 9 days according to the national standard GB / T 7759.1; (3) The volume resistivity of the rubber seal at a test voltage of 500 V is > 50 x 10 10 Ω cm according to the national standard GBT 31838.2-2019. (3) The volume resistivity of the rubber seal at a test voltage of 500 V is > 50 x 10 10 Ω cm according to the national standard GBT 31838.2-2019. (4) the rubber sealing element has a tensile strength of ≥19MPa and an elongation at break of ≥200%; (5) the rubber sealing element has a Shore A hardness of 65-76.

17. The battery cell of any one of claims 1 to 16, wherein, The electric core assembly comprises a positive electrode sheet, a separator, and a negative electrode sheet which are stacked; the battery monomer further comprises an electrolyte, and the electrolyte is arranged in the shell and infiltrates the electric core assembly.

18. A method of making a rubber seal, wherein, The method comprises the following steps: Mixing preparation raw materials to obtain a rubber mixture; the preparation raw materials include hydrogenated nitrile rubber, ethylene-propylene-diene rubber and vulcanizing agent, the weight average molecular weight of the hydrogenated nitrile rubber is 100-1000K; Sulfurizing and forming the rubber mixture to obtain a rubber seal.

19. The production method according to claim 18, wherein At least one of the following conditions is met: (1) the acrylonitrile content of the hydrogenated nitrile rubber is 15wt%-45wt%; (2) the hydrogenation degree of the hydrogenated nitrile rubber is ≥80%; (3) the weight average molecular weight of the hydrogenated nitrile rubber is 200-450K; (4) the ethylene content of the ethylene-propylene-diene rubber is 55wt%-70wt%; (5) the third monomer content of the ethylene-propylene-diene rubber is 3wt%-8wt%; (6) the Mooney viscosity ML(1+4)100℃ of the ethylene-propylene-diene rubber is 20-80; (7) in the preparation raw materials, the weight ratio of the hydrogenated nitrile rubber is 100, the weight ratio of the ethylene-propylene-diene rubber is 10-40, and the weight ratio of the vulcanizing agent is 4-12.

20. The production method according to claim 18 or 19, wherein The preparation raw materials further include one or more of reinforcing fillers, insulating fillers, processing aids, vulcanization activators, vulcanization aids and compatibilizers.

21. The production method according to claim 20, wherein In the rubber seal, the weight ratio of the hydrogenated nitrile rubber is 100, and at least one of the following conditions is met: (1) in the rubber seal, the weight ratio of the reinforcing fillers is 30-70; (2) in the rubber seal, the weight ratio of the insulating fillers is 10-30; (3) in the rubber seal, the weight ratio of the processing aids is 4-12; (4) in the rubber seal, the weight ratio of the vulcanization activators is 2-10; (5) in the rubber seal, the weight ratio of the vulcanization aids is 0.5-4; (6) in the rubber seal, the weight ratio of the compatibilizers is 0-20.

22. The production process according to any one of claims 18 to 21, wherein, The temperature of the sulfurizing and forming is 140℃-200℃, and the pressure of the sulfurizing and forming is 8MPa-20MPa.

23. A rubber seal, wherein, The rubber seal is as defined in any one of claims 1-17, or is prepared by the preparation method of any one of claims 18-22.

24. A battery, wherein, At least one of the battery cell of any one of claims 1-17 and the rubber seal of claim 23.

25. An electrical device, comprising: At least one of the battery cell of any one of claims 1-17, the rubber seal of claim 23 and the battery of claim 24.

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