Battery cells, batteries and power consuming devices

Abstract

The present application provides a battery cell, a battery, and a power consuming device, the battery cell comprising an electrode assembly and an electrolyte, the electrode assembly comprising a first polar sheet, a second polar sheet, and a separator, the first polar sheet and the second polar sheet having opposite polarities, the separator being disposed between the first polar sheet and the second polar sheet, at least one of the first polar sheet, the second polar sheet, and the separator comprising a liquid-philic polymer, the battery cell comprising a polymer represented by the following formula (I): [Equation 1] Meet TIFF2026502968000063.tif14123(I). Figure 1

Description

[Technical Field]

[0001] This application relates to the field of batteries, and more particularly to battery cells, batteries, and power consuming devices. [Background technology]

[0002] Due to their characteristics such as large capacity and long life, battery cells are widely used in electronic devices such as mobile phones, laptops, battery cars, electric vehicles, electric aircraft, electric ships, electric toy cars, electric toy ships, electric toy aircraft, and power tools.

[0003] With the ever-expanding application range of batteries, the requirements for the performance of battery cells are also gradually becoming more stringent. In order to improve the performance of battery cells, optimization and improvement of battery cells are generally carried out, but the reliability and cycle characteristics of the battery cells are still poor. Summary of the Invention

[0004] The present application has been made in view of the above-mentioned problems, and its object is to provide a battery cell, a battery, and a power consuming device.

[0005] According to a first aspect of the present application, there is provided a battery cell including an electrode assembly and an electrolyte, the electrode assembly including a first polar sheet, a second polar sheet, and a separator, the first polar sheet and the second polar sheet having opposite polarities, the separator being disposed between the first polar sheet and the second polar sheet, and at least one of the first polar sheet, the second polar sheet, and the separator including a liquid-philic polymer, the battery cell having a structure represented by the following formula:

number

[0006] Therefore, when the embodiment of the present application satisfies the above formula, the hydrophilic polymer and the electrolyte have good affinity, and the electrolyte can rapidly diffuse between the molecular chains of the hydrophilic polymer and be enveloped by the molecular chains, undergoing swelling, adsorption, polymerization, and aggregation to form an elastic, porous, sustained-release electrolyte. The sustained-release electrolyte can absorb the free electrolyte in the battery cell, reducing its presence. The trapped free electrolyte reduces the risk of extrusion, thereby reducing the risk of dendrite formation and short-circuiting between the positive and negative electrode sheets, improving the reliability and cycle performance of the battery cell. Furthermore, the absorbed free electrolyte and the elastic, porous, sustained-release electrolyte form a new gel electrolyte, ensuring high electrolyte conductivity and improving the electrical properties of the battery cell.

[0007] In some embodiments, the battery cell has the formula:

number

number

[0008] As a result, when the embodiment of the present application satisfies the above formula, it is possible to further improve both the usage reliability and cycle characteristics of the battery cell.

[0009] In some embodiments, the battery cell further comprises a compound having the formula:

number

number

[0010] As a result, when the embodiment of the present application satisfies the above formula, it is possible to further improve both the usage reliability and cycle characteristics of the battery cell.

[0011] In some embodiments, the amount of free electrolyte per unit capacity of the battery cell is b, in mg / Ah, where 0≦b≦1400, optionally 0.1≦b≦1000, and further optionally 0.3≦b≦800.

[0012] As a result, when the embodiment of the present application satisfies the above formula, it is possible to further improve both the usage reliability and cycle characteristics of the battery cell.

[0013] In some embodiments, the first polar sheet includes a current collector and an active material layer provided on at least one surface of the current collector, the active material layer including a liquid-philic polymer and active material particles, the liquid-philic polymer being distributed on the surfaces of the active material particles, and / or the active material particles are multiple and have a gap between two adjacent active material particles, and the liquid-philic polymer being distributed in the gap between the active material particles.

[0014] As a result, in the embodiment of the present application, a liquid-compatible polymer is provided on the first polar sheet, which improves the liquid retention ability of the first polar sheet, thereby further improving the usage reliability and cycle characteristics of the battery cell.

[0015] In some embodiments, the separator includes a substrate and a coating layer disposed on at least one surface of the substrate, wherein the liquid-philic polymer is distributed in voids of the substrate, and / or the liquid-philic polymer is distributed within the coating layer, and / or the liquid-philic polymer is disposed on the surface of the coating layer opposite the substrate.

[0016] As a result, in the embodiments of the present application, the liquid affinity polymer is provided on the separator, the liquid retention capacity of the separator can be improved, and the use reliability and cycle characteristics of the battery cell can be further balanced and improved.

[0017] In some embodiments, the battery cell further includes a liquid electrolyte, and the liquid electrolyte is located within the electrode assembly.

[0018] The liquid electrolyte has fluidity and can more easily flow around the active material particles, improving the transport rate of active ions. In the related art, the liquid electrolyte usually has several forms in the battery cell. One is to diffuse into the void structure of the electrode assembly and is located, for example, in the voids of the polar sheet and / or the separator. The other is to be free in the battery cell. In contrast, the liquid electrolyte in the embodiments of the present application has several forms as follows. One is to diffuse into the void structure of the electrode assembly and is located, for example, in the voids of the polar sheet and / or the separator. The other is to diffuse into the swellable polymer. As a result, the liquid electrolyte in the embodiments of the present application is substantially all located inside the electrode assembly, and there is basically no free electrolyte in the battery cell, which can significantly improve the use reliability and cycle characteristics of the battery cell.

[0019] In some embodiments, the liquid affinity polymer includes a fluoropolymer. The crystallinity of the fluoropolymer measured by differential scanning calorimetry is Xc1, where 0 < Xc1 ≤ 30%, and the melting temperature of the fluoropolymer is T m1 in °C, where 0 < T m1 ≤ 140.

[0020] In some embodiments, the glass transition temperature of the fluoropolymer is T g1 in °C, where -150 ≤ T g1 ≤ 60.

[0021] In some embodiments, the fluoropolymer includes at least one of the structural units represented by formula (AI) to formula (AIII). [Chemical Formula] In formula (AI) and formula (AII), R 11 , R 12 , R 13 and R 14 each independently include a hydrogen atom, a fluorine atom, a chlorine atom, a substituted or unsubstituted C1-C3 alkyl group, or a substituted or unsubstituted C1-C3 alkoxy group, and at least one of R 11 , R 12 , R 13 and R 14 includes a fluorine atom. When substituted, the substituent may include one or more of a nitrile group (-CN), a nitro group, a sulfonic acid group, a sulfonyl group, an amide group, a carboxyl group, an ester group, and a halogen atom. [Chemical Formula] In formula (AIII), R 15 includes a single bond or a substituted or unsubstituted C1-C3 alkyl group. When substituted, the substituent may include one or more of a nitrile group (-CN), a nitro group, a sulfonic acid group, a sulfonyl group, an amide group, a carboxyl group, an ester group, and a halogen atom. p is selected from positive integers of 1 to 3, and n is selected from positive integers of 1000 to 30000.

[0022] In some embodiments, the liquid affinity polymer further includes an ether-based polymer. The ether-based polymer is made into a sheet-like structure. The sheet-like structure is subjected to a dynamic frequency sweep test at (T m2 + 20) °C to obtain a storage modulus G'-loss modulus G" curve. The slope of the storage modulus G'-loss modulus G" curve is K1, where 1 < K1 < ∞. T m2 represents the melting temperature of the ether-based polymer, with the unit of °C. Optionally, 1 < K1 ≤ 100, and more optionally, 1 < K1 ≤ 10.

[0023] In some embodiments, the ether-based polymer includes a structural unit represented by formula (BI) and / or a structural unit represented by formula (BII),

Chemical formula

Chemical formula

[0024] In some embodiments, the substituent may include one or more of a nitrile group (-CN), a nitro group, a sulfonic acid group, a sulfonyl group, an amide group, a carboxyl group, an ester group, and a halogen atom.

[0025] In some embodiments, the liquid affinity polymer further includes an ester-based polymer. The ester-based polymer is made into a sheet-like structure. The sheet-like structure is subjected to a dynamic frequency sweep test at (T m3 + 20) °C to obtain a storage modulus G'-loss modulus G" curve. The slope of the storage modulus G'-loss modulus G" curve is K2, and 1 < K2 < ∞. T m3 represents the melting temperature of the ester-based polymer, and the unit is °C. Optionally, 1 < K2 ≤ 100, and further optionally, 1 < K2 ≤ 10.

[0026] In some embodiments, the ester-based polymer comprises a structural unit shown in formula (CI) and / or a structural unit shown in formula (CII): [ka] In formula (CI), R 31 , R 32 and R 33 each independently comprises a hydrogen atom or a substituted or unsubstituted C1-C8 alkyl group; R 34 comprises a substituted or unsubstituted C1-C8 alkyl group or a substituted or unsubstituted C1-C8 hydroxyalkyl group; [ka] In formula (CII), R 35 contains a substituted or unsubstituted C2-C6 methylene group, and optionally R 35 independently comprises a substituted or unsubstituted C2-C4 methylene group.

[0027] In some embodiments, the substituents may include one or more of a nitrile group (-CN), a nitro group, a sulfonic acid group, a sulfonyl group, an amide group, a carboxyl group, an ester group, and a halogen atom.

[0028] In some embodiments, the liquid-philic polymer comprises an aldehyde ketone polymer, and the aldehyde ketone polymer is formed into a sheet-like structure, and the sheet-like structure is (T m4 A dynamic frequency sweep test was performed at +20°C to obtain the elastic modulus G'-loss elastic modulus G" curve, and the slope of the elastic modulus G'-loss elastic modulus G" curve was K3, 0.8 <K3<∞であり、T m4 represents the melting temperature of the aldehyde ketone polymer, in ° C., optionally 0.8≦K3≦100, and further optionally 0.8≦K3≦10.

[0029] In some embodiments, the aldehyde ketone polymer comprises a structural unit shown in formula (DI) and / or a structural unit shown in formula (DII): [ka] In formula (DI), R 41 contains a single bond, a substituted or unsubstituted C1-C6 methylene group, and R 42 contains a hydrogen atom, a substituted or unsubstituted C1-C6 alkyl group, [ka] In formula (DII), R 43 ~R 46 each independently comprises a hydrogen atom, a hydroxyl group, a substituted or unsubstituted C1-C3 alkyl group, a substituted or unsubstituted C1-C3 hydroxyalkyl group, or a substituted or unsubstituted C1-C3 alkoxy group, and r and s are each independently selected from integers of 0 to 5, and at least one of r and s is selected from a positive integer.

[0030] In some embodiments, the substituents may include one or more of a nitrile group (-CN), a nitro group, a sulfonic acid group, a sulfonyl group, an amide group, a carboxyl group, an ester group, and a halogen atom.

[0031] In some embodiments, the molecular weight of the hydrophilic polymer is 1.2×10 5 g / mol to 1 × 10 6 g / mol.

[0032] According to a second aspect of the present application, there is provided a battery including a battery cell according to any of the embodiments of the first aspect of the present application.

[0033] According to a third aspect of the present application, there is provided a power consuming device comprising a battery according to any embodiment of the second aspect of the present application. [Brief explanation of the drawings]

[0034] In order to more clearly describe the technical solutions in the embodiments of the present application, the following briefly describes the drawings required for the embodiments of the present application. It should be understood that the drawings shown below are only some embodiments of the present application, and those skilled in the art can further obtain other drawings based on the drawings without any creative efforts.

[0035] [Figure 1] 1 is a schematic diagram of one embodiment of a battery cell of the present application. [Figure 2] 2 is an exploded schematic view of the battery cell shown in FIG. 1 according to an embodiment. [Figure 3] 1 is a schematic diagram of a battery module according to an embodiment of the present application; [Figure 4] 1 is a schematic diagram of an embodiment of a battery pack of the present application. [Figure 5] 5 is an exploded schematic view of the battery pack shown in FIG. 4 according to the embodiment. [Figure 6] 1 is a schematic diagram of one embodiment of a power consuming device that includes a battery cell of the present application as a power source.

[0036] The drawings are not drawn to scale. [Explanation of symbols]

[0037] 1 battery pack, 2 upper housing, 3 lower housing, 4 battery module, 5 battery cell, 51 housing, 52 electrode assembly, 53 cover plate, 6 Power consumption equipment. DETAILED DESCRIPTION OF THE INVENTION

[0038] Hereinafter, detailed descriptions will be given of embodiments specifically disclosing the battery cell, battery, and power consumption device of the present application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and redundant descriptions of structures that are actually the same may be omitted. This is to avoid the following description becoming unnecessarily long and to facilitate understanding by those skilled in the art. Note that the drawings and the following description are provided to enable those skilled in the art to fully understand the present application, and are not intended to limit the subject matter described in the claims.

[0039] The "ranges" disclosed herein are defined in the form of lower and upper limits, and a given range is defined by selecting one lower limit and one upper limit, with the selected lower and upper limits defining the boundaries of the particular range. Such defined ranges may be inclusive or exclusive of their endpoints, and are arbitrarily combinable; i.e., any lower limit can be combined with any upper limit to form a single range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a particular parameter, it is understood that ranges of 60 to 110 and 80 to 120 are also contemplated. Furthermore, if 1 and 2 are listed as minimum range values ​​and 3, 4, and 5 are listed as maximum range values, the ranges 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5 are all contemplated. In this application, unless otherwise specified, a numerical range "a to b" is a shorthand representation of any combination of real numbers a to b, where a and b are both real numbers. For example, the numerical range "0-5" represents a list of all real numbers between "0-5" in this specification, and "0-5" is merely a shorthand representation of combinations of these numbers. Also, expressing a parameter as an integer ≧2 is equivalent to disclosing that this parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0040] Unless otherwise stated, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution. Unless otherwise stated, all technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

[0041] All steps in this application can be performed sequentially or randomly, and are preferably performed sequentially, unless otherwise specified. For example, if a method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, if it is said that the method may further include step (c), it means that step (c) may be added to the method in any order, e.g., the method may include steps (a), (b), and (c), or may include steps (a), (c), and (b), or may include steps (c), (a), and (b), etc.

[0042] The terms "comprise" and "comprises" referred to herein refer to both open and closed forms unless otherwise specified. For example, "comprise" and "comprises" can indicate that other elements not listed may also be included or may be included, or that only the listed elements may be included or included.

[0043] In this application, unless otherwise stated, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied by either A being true (or present) and B being false (or absent), or A being false (or absent) and B being true (or present), or both A and B being true (or present).

[0044] As used herein, the terms "plurality" and "plurality" mean two or more.

[0045] Unless otherwise explained, terms used herein have the same meaning as commonly understood by one of ordinary skill in the art.

[0046] Unless otherwise specified, the numerical values ​​of each parameter described in this application can be measured by various test methods commonly used in this field, for example, according to the test methods shown in the examples of this application.

[0047] The term "alkyl group" encompasses straight-chain and branched alkyl groups. For example, the alkyl group may be a C1-C5 alkyl group, a C1-C4 alkyl group, a C1-C3 alkyl group, or a C1-C2 alkyl group. In some embodiments, alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and the like. Additionally, alkyl groups may be optionally substituted. When substituted, the substituents may include fluorine atoms.

[0048] The term "alkoxy group" refers to a group in which an alkyl group and an oxygen atom are joined by a single bond. For example, the alkoxy group may be a C1-C5 alkoxy group, a C1-C3 alkoxy group, or a C1-C2 alkoxy group. In some embodiments, the alkoxy group may include methoxy, ethoxy, and propoxy. Additionally, the alkoxy group may be optionally substituted.

[0049] The term "halogen atom" refers to fluorine atom, chlorine atom, bromine atom, and the like.

[0050] The term "hydrogen" refers to 1H (protium, H), 2H (deuterium, D), or 3H (tritium, T). In each embodiment, "hydrogen" may be 1H (protium, H).

[0051] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. The separator is disposed between the positive electrode sheet and the negative electrode sheet and serves mainly to prevent short circuits between the positive electrode sheet and the negative electrode sheet, while allowing active ions to pass freely through the separator to form a circuit.

[0052] The electrolyte wets the electrode assembly, allowing active ions to smoothly migrate from the positive electrode sheet of the electrode assembly through the separator to the negative electrode sheet. However, during use of the battery cell, the volume of the electrode assembly may change (e.g., expansion and deformation) due to the insertion or desorption of active ions, which may cause the electrolyte wetted by the electrode assembly to be constantly extruded. Not all of the extruded electrolyte may be absorbed into the electrode assembly, resulting in a lack of liquid in the electrode assembly, causing localized metal deposition and increasing the risk of dendrite formation. As the dendrites grow, they may penetrate the separator, causing a short circuit between the positive electrode sheet and the negative electrode sheet, thereby deteriorating the reliability and cycle characteristics of the battery cell.

[0053] In view of the above, the present application provides a battery cell in which a hydrophilic polymer is added to an electrode assembly, and after the hydrophilic polymer comes into contact with and mixes with a free electrolyte, the electrolyte is encapsulated between the polymer molecular chains to form a gel electrolyte, which not only ensures the electrical properties of the battery cell but also improves the reliability of the battery cell. The technical solution of the present application is described in detail below.

[0054] Battery cell According to a first aspect, the present application provides a battery cell including an electrode assembly and an electrolyte, the electrode assembly including a first polar sheet, a second polar sheet, and a separator, the first polar sheet and the second polar sheet having opposite polarities, the separator being disposed between the first polar sheet and the second polar sheet, and at least one of the first polar sheet, the second polar sheet, and the separator including a liquid-philic polymer.

[0055] The battery cell has the following formula:

number

[0056] In the present embodiment, M-M' can be understood to mean the total amount of electrolyte in the battery cell. After the electrolyte is injected into the battery cell, the electrolyte mainly exists in several forms: adsorbed to the polar sheet and / or separator; forming a gel electrolyte with the liquid-philic polymer; and remaining liquid and free in the battery cell. y represents the mass of the electrolyte in the third state, i.e., the mass of free electrolyte. The mass of free electrolyte can be measured using the following method: a new battery cell is fully discharged to 0% SOC, weighed, and the weighed mass is designated as M. A hole with a diameter of 5-8 mm is drilled at a local position on the battery cell, and the battery cell is placed above a container with the hole facing downward and directly above the container. The free electrolyte inside the battery cell drips into the container below. The battery cell is left in this state for 3-5 hours, allowing all the free electrolyte inside to drip into the container. The weight of the electrolyte in the container is then weighed to obtain y. The battery cell is then dried at 60°C to 95°C for 24 to 48 hours, immersed in a solvent, dimethyl carbonate (DMC), for 12 hours, and then dried at 60°C to 95°C for 24 to 48 hours. The dried battery cell is then weighed, and the weighed mass is designated as M'. For example, the battery cell is dried at 60°C for 5 hours and then weighed. In the present embodiment, the new battery cell may be a newly delivered battery cell (which has not been used for any charge / discharge cycles since chemical formation), or may be a battery cell that has been installed in a power consuming device and has been used for less than 10 cycles.

[0057]

number

[0058] When the present embodiment satisfies the above formula, the hydrophilic polymer and the electrolyte have good affinity, and the electrolyte can rapidly diffuse between the molecular chains of the hydrophilic polymer and be enveloped by the molecular chains, swelling, and adsorption to form an elastic, porous, sustained-release electrolyte. The sustained-release electrolyte can absorb the free electrolyte in the battery cell, reducing its presence. The trapped free electrolyte reduces the risk of extrusion, thereby reducing the risk of dendrite formation and short-circuiting between the positive and negative electrode sheets, improving the reliability and cycle performance of the battery cell. Furthermore, the absorbed free electrolyte and the elastic, porous, sustained-release electrolyte form a new gel electrolyte, ensuring high electrolyte conductivity and improving the electrical properties of the battery cell.

[0059] Therefore, the embodiment of the present application

number

number

number

[0060] For example,

number

[0061] When the embodiments of the present application satisfy the following conditions, it is possible to further improve both the usage reliability and cycle characteristics of the battery cell.

[0062] In some embodiments, the battery cell further comprises a compound having the formula:

number

number

[0063] m1 represents the mass of the electrode assembly before drying, and is expressed in g. The mass before drying refers to the mass of the electrode assembly obtained by disassembling the battery cell, removing the electrode assembly, and leaving the electrode assembly to stand for 3 to 5 hours to allow the free electrolyte in the electrode assembly to flow out.

[0064] m2 represents the mass of the electrode assembly after drying, and is expressed in g. The mass after drying refers to the mass of the electrode assembly obtained after the electrolyte adsorbed on the electrode assembly has been dried and removed. For example, the electrode assembly is placed in an oven and dried at 60°C to 95°C for 24 to 48 hours, then immersed in a solvent, dimethyl carbonate (DMC), for 12 hours, and then placed in an oven and dried at 60°C to 95°C for 24 to 48 hours. The dried electrode assembly is then weighed.

[0065] m2-m1 is the mass of the electrolyte adsorbed on the electrode assembly,

number

[0066] The embodiment of the present application is within the range of the above formula

number

number

[0067] 0%、0.001%、0.002%、0.003%、0.004%、0.005%、0.006%、0.007%、0.008%、0.009%、0.01%、0.012%、0.014%、0.016%、0.018%、0.02%、0.022%、0.024%、0.026%、0.028%、0.03%、0.032%、0.034%、0.036%、0.038%、0.04%、0.042%、0.044%、0.046%、0.048%、0.05%、0.052%、0.054%、0.056%、0.058%、0.06%、0.062%、0.064%、0.066%、0.068%、0.07%、0.072%、0.074%、0.076%、0.078%、0.08%、0.082%、0.084%、0.086%、0.088%、0.09%、0.092%、0.094%、0.096%、0.098%、0.10%、0.15%、0.20%、0.25%、0.30%、0.35%、0.40%、0.45%、0.50%、0.55%、0.60%、0.65%、0.70%、0.75%、0.80%、0.85%、0.90%、0.95%、1.00%、1.10%、1.20%、1.30%、1.40%、1.50%、1.60%、1.70%、1.80%、1.90%、2.00%、2.10%、2.20%、2.30%、2.40%、2.50%、2.60%、2.70%、2.80%、2.90%、3.00%、3.10%、3.20%、3.30%、3.40%、3.50%、3.60%、3.70%、3.80%、3.90%、4.00%、4.10%、4.20%、4.30%、4.40%、4.50%、4.60%、4.70%、4.80%、4.90%、5.00%、5.10%、5.20%、5.30%、5.40%、5.50%、5.60%、5.70%、5.80%、5.90%、6.00%、6.10%、6.20%、6.30%、6.40%、6.50%、6.60%、6.70%、6.80%、6.90%、7.00%、7.10%、7.20%、7.30%、7.40%、7.50%、7.60%、7.70%、7.80%、7.90%、8.00%、8.10%、8.20%、8.30%、8.40%、8.50%、8.60%、8.70%、8.80%、8.90%、9.00%、9.10%、9.20%、9.30%、9.40%、9.50%、9.It may be 60%, 9.70%, 9.80%, 9.90%, 10%, or a range consisting of any two of the above values.

[0068] In some embodiments, the battery cell further comprises a compound having the formula:

number

number

[0069]

number

[0070] The embodiment of the present application is within the range of the above formula

number

number

[0071] In some embodiments, the amount of free electrolyte per unit capacity of the battery cell is b, expressed in mg / Ah, and 0≦b≦1400. When the amount of free electrolyte per unit capacity of the battery cell, b, satisfies the above range, the usage reliability and cycle characteristics of the battery cell can be further improved.

[0072] Alternatively, 0.1≦b≦1000, and more preferably, 0.3≦b≦800. Illustratively, the amount of free electrolyte per unit capacity of the battery cell is 0 mg / Ah, 0.001 mg / Ah, 0.002 mg / Ah, 0.003 mg / Ah, 0.004 mg / Ah, 0.005 mg / Ah, 0.006 mg / Ah, 0.007 mg / Ah, 0.008 mg / Ah, 0.009 mg / Ah, 0.01 mg / Ah, 0.02 mg / Ah, 0.0 3mg / Ah, 0.04mg / Ah, 0.05mg / Ah, 0.06mg / Ah, 0.07mg / Ah, 0.08mg / Ah, 0.09mg / Ah, 0.1mg / Ah, 0 .2mg / Ah, 0.3mg / Ah, 0.5mg / Ah, 1.0mg / Ah, 5.0mg / Ah, 10.0mg / Ah, 20.0mg / Ah, 50.0mg / Ah, 80.0 mg / Ah, 100mg / Ah, 120mg / Ah, 150mg / Ah, 180mg / Ah, 200mg / Ah, 220mg / Ah, 250mg / Ah, 300mg / Ah , 350mg / Ah, 400mg / Ah, 450mg / Ah, 500mg / Ah, 550mg / Ah, 600mg / Ah, 650mg / Ah, 700mg / Ah, 750mg / Ah, 800mg / Ah, 850mg / Ah, 900mg / Ah, 950mg / Ah, 1000mg / Ah, 1050mg / Ah, 1100mg / Ah, 1150mg / Ah, 1200mg / Ah, 1250mg / h, 1300mg / Ah, 1350mg / Ah, 1400mg / Ah, or a range consisting of any two of the above values.

[0073] In the present embodiment, b is equal to y / x, where x represents the nominal capacity of the battery cell in Ah, and y is the mass of the free electrolyte referred to in the previous sentence.

[0074] In the embodiments of the present application, x can be measured using methods and devices known in the art, and is, for example, the product of the total current that can be output when a battery cell is discharged to its end voltage at a constant current and voltage of 0.33 C in a fully charged state and the discharge time.

[0075] In some embodiments, after the battery cell is subjected to a linear sweep vibration test, the battery cell is charged to 100% SOC, a hole is drilled in the battery cell, and the hole is placed at the lowest vertical position. The mass of the electrolyte flowing out of the battery cell is recorded as M1, where 0≦M1≦6 g, and optionally M1 is 0 g; where: The vibration direction of the linear sweep vibration test is a simple vertical harmonic motion, The vibration frequency of the linear sweep vibration test is 10 Hz to 55 Hz, The maximum acceleration of the linear sweep vibration test is 30 m / s 2 and The number of sweep cycles in the linear sweep vibration test is 10; The vibration time for the linear sweep vibration test is 3 hours.

[0076] In related art, during use, battery cells may experience vibrations and other phenomena due to the action of external forces. The electrolyte located in the electrode assembly may detach from the electrode assembly under the action of vibration, forming free electrolyte. The free electrolyte in the battery cell may leak, causing corrosion of the battery cell and posing risks such as battery cell failure. In embodiments of the present application, the battery cell is subjected to static and vibration treatments to effectively collect and discharge the electrolyte inside the battery cell, thereby more accurately determining whether electrolyte is flowing between the battery cell housing and the electrode assembly and determining the amount of free electrolyte. When the battery cell of the present application satisfies the above conditions, the amount of free electrolyte in the battery cell is extremely small, or even substantially free of free electrolyte, thereby significantly improving the usage reliability and cycle characteristics of the battery cell.

[0077] Illustratively, M1 may be 0, 0.05g, 0.10g, 0.15g, 0.20g, 0.25g, 0.3g, 0.35g, 0.4g, 0.45g, 0.5g, 0.55g, 0.60g, 0.65g, 0.70g, 0.75g, 0.80g, 0.85g, 0.90g, 0.95g, 1.00g, 1.10g, 1.20g, 1.30g, 1.40g, 1.50g, 1.60g, 1.70g, 1.80g, 1.90g, 2.00g, 2.10g, 2.20g, The value of M1 may be 2.30g, 2.40g, 2.50g, 2.60g, 2.70g, 2.80g, 2.90g, 3.00g, 3.10g, 3.20g, 3.30g, 3.40g, 3.50g, 3.60g, 3.70g, 3.80g, 3.90g, 4.00g, 4.10g, 4.20g, 4.30g, 4.40g, 4.50g, 4.60g, 4.70g, 4.80g, 4.90g, 5.00g, 6.00g, or a range consisting of any two of the above values. If M1 is 0g, it indicates that the amount of free electrolyte is 0, i.e., the battery cell is substantially free of free electrolyte after the linear sweep vibration test.

[0078] In some embodiments, after the linear sweep vibration test is performed on the battery cell, the housing is disassembled, the electrode assembly is removed, and a pressing test is performed on the battery cell. The volume of the electrolyte flowing out of the electrode assembly is recorded as M2 (the pressing device is empty, and a weighing balance and an electrolyte collecting container are installed at the bottom). 0≦M2≦0.6 g, and optionally, M2 is 0 g;

[0079] The pressing direction of the pressing test is perpendicular to the thickness direction of the electrode assembly, The pressure level in the compression test is 0.35 MPa.

[0080] In the related art, a battery cell may be subjected to external pressure during use, and the electrolyte located in the electrode assembly may detach from the electrode assembly under pressure, forming free electrolyte. The free electrolyte in the battery cell may leak, causing corrosion of the battery cell and posing risks such as battery cell failure. In an embodiment of the present application, a pressure test is performed on the battery cell to effectively force the electrolyte inside the battery cell to flow out, thereby more accurately determining whether electrolyte exists between the battery cell housing and the electrode assembly and determining the amount of free electrolyte. When the battery cell of the embodiment of the present application satisfies the above conditions, the amount of free electrolyte in the battery cell is extremely small, or even substantially free of free electrolyte, thereby significantly improving the usage reliability and cycle characteristics of the battery cell.

[0081] Illustratively, M2 may be 0, 0.05 mg, 0.10 mg, 0.15 mg, 0.20 mg, 0.25 mg, 0.3 mg, 0.35 mg, 0.4 mg, 0.45 mg, 0.5 mg, 0.55 mg, 0.60 mg, 0.65 mg, 0.70 mg, 0.75 mg, 0.80 mg, 0.85 mg, 0.90 mg, 0.95 mg, 1.00 mg, 1.10 mg, 1.20 mg, 1.30 mg, 1.40 mg, 1.50 mg, 1.60 mg, 1.70 mg, 1.80 mg, 1.90 mg, 2.00 mg, 2.10 mg, 2.20 mg, 2.30 mg, 2.40 mg, 2.50 mg, 2.60 mg, 2.70 mg, 2.80 mg, 2.90 mg, 3.00 mg, 3.10 mg, 3.20 mg, 3.30 mg, 3.40 mg, 3.50 mg, 3.60 mg, 3.70 mg, 3.80 mg, 3.90 mg, 4.00 mg, 4.10 mg, 4.20 mg, 4.30 mg, 4.40 mg, 4.50 mg, 4.60 mg, 4.70 mg, 4.80 mg, 4.90 mg, 5.00 mg, 5.10 mg, 5.20 mg, 5.30 mg, 5.40 mg, 5.50 mg, 5.60 mg, 5.70 mg, 5.80 mg, 5.90 mg, 5.10 mg, 5.20 mg, 5.30 .50mg, 2.60mg, 2.70mg, 2.80mg, 2.90mg, 3.00mg, 3.10mg, 3.20mg, 3.30mg, 3.40mg, 3.50mg, 3.60mg, 3.70mg, 3.80mg, 3.90mg, 4.00mg, 4.10mg, 4.20m g, 4.30mg, 4.40mg, 4.50mg, 4.60mg, 4.70mg, 4.80mg, 4.90mg, 5.00mg, 10.00mg, 20.00mg, 30.00mg, 40.00mg, 50.00mg, 60.00mg, 70.00mg, 80.00mg, 9 0.00mg, 100.00mg, 110.00mg, 120.00mg, 130.00mg, 140.00mg, 150.00mg, 160.00mg, 170.00mg, 180.00mg, 190.00mg, 200.00mg, 210.00mg, 220.00mg , 230.00mg, 240.00mg, 250.00mg, 260.00mg, 270.00mg, 280.00mg, 290.00mg, 300.00mg, 310.00mg, 320.00mg, 330.00mg, 340.00mg, 350.00mg, 360.0 The value may be 0 mg, 370.00 mg, 380.00 mg, 390.00 mg, 400.00 mg, 410.00 mg, 420.00 mg, 430.00 mg, 440.00 mg, 450.00 mg, 460.00 mg, 470.00 mg, 480.00 mg, 490.00 mg, 500.00 mg, 510.00 mg, 520.00 mg, 530.00 mg, 540.00 mg, 550.00 mg, 560.00 mg, 570.00 mg, 580.00 mg, 590.00 mg, 600.00 mg, or a range consisting of any two of the above values.If M2 is 0g, it indicates that the amount of free electrolyte is 0, that is, the battery cell has substantially no free electrolyte inside after the pressing test.

[0082] In some embodiments, a voltage of 200V is applied to the battery cell to form a circuit, the duration is 4 hours, and the absolute value of the temperature change of the battery cell is ≦4° C.

[0083] For example, if a 200V current circuit is formed by connecting the negative terminal of a battery cell to the inside of the outer case, the temperature fluctuation range of the battery cell will be 4°C or less within 4 hours, and there will be no malfunctions such as fire or explosion. In particular, when the free electrolyte y=0, the temperature fluctuation range is small, greatly improving the reliability of the battery cell.

[0084] In some embodiments, the polar sheets include a liquid-philic polymer. Specifically, the first polar sheet includes a current collector and an active material layer disposed on at least one surface of the current collector, the active material layer including a liquid-philic polymer and active material particles. The liquid-philic polymer may be disposed only in the first polar sheet, or only in the second polar sheet, or the liquid-philic polymer may be disposed in both the first and second polar sheets. The first polar sheet may be a positive electrode sheet, and the second polar sheet may be a negative electrode sheet, or the first polar sheet may be a negative electrode sheet, and the second polar sheet may be a positive electrode sheet.

[0085] For example, the liquid-philic polymer is distributed on the surface of the active material particles, and it is understood that the active material particles and binder, etc., harden on the surface of the current collector to form a film layer, and the liquid-philic polymer is disposed on the surface of the film layer opposite the current collector. By disposing in this manner, the electrolyte can rapidly diffuse between the molecular chains of the liquid-philic polymer and be enveloped by the molecular chains to form a gel-like substance on the surface of the active material particles, and adhere to the surface of the active material particles to protect the active material particles. This allows the active material particles and the electrolyte to closely associate with each other, improves solid-liquid interface performance, reduces side reactions between the active material particles and the electrolyte, and improves the reliability and electrical characteristics (e.g., cycle characteristics and storage performance) of the battery cell.

[0086] Specifically, the polar sheet is manufactured as follows.

[0087] Active material particles are added to a solvent to produce an active paste.

[0088] The active paste is applied to the surface of the current collector, and is dried and cured to form a film layer.

[0089] A liquid-philic polymer is applied to the surface of the film layer to form a polar sheet.

[0090] In another example, the active material particles are multiple and have a gap between two adjacent active material particles, and the liquid-compatible polymer is distributed in the gap between the active material particles. This installation form can improve the liquid storage capacity of the active material layer, i.e., its ability to confine the electrolyte, thereby improving the reliability and electrical properties of the battery cell.

[0091] Specifically, the manufacturing process of one embodiment of the polar sheet includes:

[0092] The liquid-philic polymer is dispersed in a solvent to form a mixed system.

[0093] Active material particles are added to the mixture to prepare a paste.

[0094] The paste is applied to the surface of a current collector, and is dried and hardened to form a polar sheet.

[0095] Specifically, the manufacturing process of another embodiment of the polar sheet includes:

[0096] A liquid-compatible polymer and active material particles are dispersed in a solvent to produce a paste.

[0097] The paste is applied to the surface of a current collector, and is dried and hardened to form a polar sheet.

[0098] As yet another example, the liquid-philic polymer is distributed on the surfaces of the active material particles, and the liquid-philic polymer is distributed in the voids between the active material particles.

[0099] Specifically, the manufacturing process of one embodiment of the polar sheet includes:

[0100] A liquid-compatible polymer and active material particles are dispersed in a solvent to produce a paste.

[0101] The paste is applied to the surface of a current collector, and is dried and cured to form a film layer.

[0102] A liquid-philic polymer is applied to the surface of the film layer to form a polar sheet.

[0103] In another embodiment, the separator comprises a liquid-compatible polymer, and specifically, the separator may comprise a substrate, and optionally, the separator may further comprise a coating layer provided on at least one surface of the substrate.

[0104] For example, the substrate generally has a porous structure, in which voids exist, and the liquid-philic polymer is distributed in the voids of the substrate.

[0105] In another example, the liquid-philic polymer may be distributed within the coating layer.

[0106] In yet another example, the liquid-philic polymer may be provided on the surface of the coating layer opposite to the substrate.

[0107] The specific distribution position of the liquid-philic polymer may be any one of the above three types, any two of them, or a combination of the above three types.

[0108] In yet another embodiment, the liquid-philic polymer may be provided in the polar sheet and the separator, and the specific installation position is as described above, and the description thereof will be omitted here.

[0109] In some embodiments, the liquid-philic polymer may include at least one of a fluoro-based polymer, an ether-based polymer, an ester-based polymer, and an aldehyde-ketone-based polymer.

[0110] [Fluoropolymer] In some embodiments, the liquid-philic polymer comprises a fluoropolymer, and the fluoropolymer has a crystallinity measured by differential scanning calorimetry of X C1 The unit is %, and 0 <X C1 ≦30%, and the melting temperature of the fluoropolymer is T m1 The unit is °C, and 0 <T m1 ≦140.

[0111] Crystallization refers to the process in which atoms, ions, or molecules in a material are arranged in a certain spatial order to form an order. The structure of a polymer in a crystal is determined by both intramolecular and intermolecular forces, and intermolecular forces affect the packing density between molecular chains. Crystallinity X C1 is used to characterize the degree of crystallization in a material and can be measured using differential scanning calorimetry (DSC). Specifically, the measurement steps are as follows: Take a 0.5g-0.8g sample, place it in a crucible, and heat and cool the sample under a nitrogen atmosphere at a heating rate of 10°C / min to measure the intrinsic T of the material. g1Starting at a temperature 20°C lower than the material's inherent T m1 The temperature is raised to the cutoff temperature of the process, which is 20°C higher than the actual glass transition temperature T of the material based on the heat absorption / dissipation peak value or transition point of the material in the process. g1 and melting temperature T m1 etc. will be determined.

[0112] As a result, fluoropolymers have a relatively low crystallinity and melting temperature, which means that the molecular chains tend to be sparsely arranged, the inter-chain forces are small, adjacent molecular chains open more easily, and segment movement is achieved through intermolecular internal rotation, forming a relatively flexible molecular chain structure. Furthermore, the fluoropolymer and the electrolyte in the battery cell can form a gel-like substance, improving the usage reliability and cycle characteristics of the battery cell.

[0113] For example, the crystallinity X of the fluoropolymer measured by differential scanning calorimetry C1 The percentage may be 5%, 10%, 15%, 20%, 25%, 30%, or a range consisting of any two of the foregoing values.

[0114] Illustratively, the melting temperature of the fluoropolymer may be 10°C, 20°C, 50°C, 70°C, 90°C, 100°C, 120°C, 140°C, or a range consisting of any two of the foregoing values.

[0115] In some embodiments, the glass transition temperature of the fluoropolymer is T g1 The unit is °C, and -150≦T g1 ≦60.

[0116] The glass transition temperature (GTC) is the temperature at which a polymer segment transitions from frozen to mobile. The GTC has a certain effect on the flexibility of the polymer molecular chain. The lower the GTC, the better the flexibility of the polymer molecular chain at room temperature. The higher the GTC, the worse the flexibility of the molecular chain at room temperature. The GTC can be measured using differential scanning calorimetry (DSC). When the GTC of a polymer is relatively low, the flexibility of the molecular chain segments is good, and adjacent molecular chains open more easily. For example, the GTC of a fluoropolymer may be -150°C, -120°C, -100°C, -80°C, -60°C, -30°C, 0°C, 30°C, 60°C, or a range consisting of any two of the above values.

[0117] In some embodiments, the fluoropolymer comprises at least one of structural units shown in formula (AI) through structural units shown in formula (AIII): [ka] In formula (AI) and formula (AII), R 11 , R 12 , R 13 and R 14 each independently comprises a hydrogen atom, a fluorine atom, a chlorine atom, a substituted or unsubstituted C1-C3 alkyl group, or a substituted or unsubstituted C1-C3 alkoxy group, and R 11 , R 12 , R 13 and R 14 at least one of which contains a fluorine atom, and when substituted, the substituents may include one or more of a nitrile group (—CN), a nitro group, a sulfonic acid group, a sulfonyl group, an amide group, a carboxyl group, an ester group, and a halogen atom; In formula (AIII), R 15includes a single bond, a substituted or unsubstituted C1-C3 alkyl group, and if substituted, the substituents may include one or more of a nitrile group (-CN), a nitro group, a sulfonic acid group, a sulfonyl group, an amide group, a carboxyl group, an ester group, and a halogen atom, and p is selected from a positive integer of 1 to 3. n is selected from a positive integer of 1,000 to 30,000.

[0118] In some embodiments, R 11 , R 12 , R 13 and R 14 each independently comprise a hydrogen atom, a fluorine atom, a chlorine atom, a substituted or unsubstituted C1-C2 alkyl group, or a substituted or unsubstituted C1-C2 alkoxy group, and optionally R 11 , R 12 , R 13 and R 14 each independently includes a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, a fluoromethyl group, a methoxy group, or a perfluoromethoxy group.

[0119] In some embodiments, the fluoropolymer comprises at least one of structural units shown in formula (AI-1) to structural units shown in formula (AI-11): [ka]

[0120] In some embodiments, the fluoropolymer comprises at least one of the structural units shown in formula (AII-1) to (AII-5): [ka]

[0121] In some embodiments, the fluoropolymer comprises at least one of the structural units shown in formula (AIII-1) to the structural unit shown in formula (AIII-3): [ka]

[0122] Exemplarily, the fluoropolymer includes one or more of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), perfluoroethylenepropene copolymer (FEP), perfluoroalkoxyalkane (PFA), perfluoropolyether (PFPE), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyvinylidene fluoride-trifluoroethylene copolymer (PVDF-TrFE), and perfluoro(1-butenyl vinyl ether) polymer (abbreviated as CYTOP).

[0123] Optionally, the fluoropolymer comprises one or more of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), perfluoroethylene propene copolymer (FEP), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyvinylidene fluoride-trifluoroethylene copolymer (PVDF-TrFE).

[0124] The fluoropolymer may be derived from one or more of the following monomers: fluorocyclohexane, fluoroethylene, 1,2-difluoroethylene, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene, 3,3,3-trifluoropropylene, trifluoropropylene, tetrafluoropropylene, and pentafluoropropylene. Alternatively, the fluoropolymer may be derived from at least two of the following monomers: fluorocyclohexane, fluoroethylene, 1,2-difluoroethylene, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene, 3,3,3-trifluoropropylene, trifluoropropylene, tetrafluoropropylene, and pentafluoropropylene.

[0125] The monomers used in the above fluoropolymers are all short-chain monomers, which are advantageous for polymerizing to form a linear or short-chain branched structure. This structural type has a low degree of entanglement, which is advantageous for improving the flexibility of the molecular chains, and the molecular chains can be sufficiently spread in the electrolyte, thereby further improving the interfacial properties of the active material.

[0126] In some embodiments, n is selected from a positive integer of 5,000 to 20,000, and / or the molecular weight of the hydrophilic polymer is 2×10 5 g / mol to 1.5 × 10 6 g / mol. When the molecular weight of the polymer is in the above range, it can ensure that the polymer exhibits a certain solubility in the electrolyte, and at the same time, it is difficult for the polymer to be completely dissolved or dispersed in the electrolyte, which helps to control the distribution and dispersion of the polymer on the surface of the active material. In addition, it can further improve the flexibility between the molecular chains of the polymer, and the interaction force between the molecular chains is relatively weak, which is favorable for the solvent molecules in the electrolyte to open the molecular chains, enter between the molecular chains, and be enveloped by the molecular chains, which helps the active ions to enter the active material through the solvent, realizing the smooth and fast movement of the active ions.

[0127] Illustratively, the molecular weight of the polymer is 2×10 5 g / mol, 5 × 10 5 g / mol, 8 × 10 5 g / mol, 1×10 6 g / mol, 1.5 × 10 6 It may be g / mol or a range consisting of any two of the above values.

[0128] [Ether polymer] In some embodiments, the liquid-philic polymer comprises an ether-based polymer, and the ether-based polymer is formed into a sheet-like structure, and the sheet-like structure is (T m2 A dynamic frequency sweep test was performed at +20°C to obtain the elastic modulus G'-loss elastic modulus G" curve, and the slope of the elastic modulus G'-loss elastic modulus G" curve was K1, and 1 <K1<∞であり、Tm2 indicates the melting temperature of the ether polymer, and the unit is °C.

[0129] Specifically, the process for producing the sheet-like structure is as follows: The ether-based polymer is vacuum-dried at 80°C for 12 hours. After drying, the ether-based polymer is hot-pressed into thin pieces using a vulcanization press. The hot-press temperature is (T m2 The temperature was set at +20°C, the rolling thickness was 1-2 mm, the rolling time was 2 minutes, and the pressure was 8 MPa. After rolling for 2 minutes, the sample was removed and cold-pressed in another vulcanization press of the same type at a pressure of 10 MPa. A circular mold with a diameter of 25 mm was used to obtain a fixed-size circular polymer sheet (sheet-like structure). For example, the sheet-like structure may be a circular sheet with a thickness of 1-2 mm and a diameter of 25 mm, and standard samples may be prepared according to the requirements of the testing equipment.

[0130] According to the conventional conclusion of linear viscoelasticity, for polymers, especially linear polymers, the elastic modulus G'-loss modulus G" curve conforms to the frequency dependence in the terminal region (the range toward the maximum angular velocity) of the elastic modulus G'-loss modulus G" curve, and the longest chain of the polymer contributes to the viscoelastic behavior.

[0131] The specific steps of the dynamic frequency sweep test are as follows: The dynamic frequency sweep test was performed using a TA-AR2000EX rotational rheometer (TA Instruments, USA). The parallel plates had a diameter of 25 mm and a thickness of 0.9 mm. To ensure the test was performed in the linear viscoelastic region, the strain during the dynamic frequency sweep test was 2% and the test temperature was T. m2 +20℃, and the test frequency sweep range is 500rad / s≦w 2 ≦0.05 rad / s, which makes it easier to obtain data in the lowest possible frequency range.

[0132] The dynamic frequency sweep test can characterize the degree of entanglement of molecular chains in the solid-phase melting (melt state). Compared with the linear structure or short-chain branched structure, the long-chain branched structure, network structure, and low-crosslinked structure have a greater degree of entanglement and show behavior deviating from the linear end, while the ether-based polymer shows solid-phase behavior. When the ether-based polymer of the embodiment of the present application satisfies the above range, the entanglement state of the molecular chains can be further reduced, which is advantageous for the diffusion of solvent molecules in the electrolyte between the molecular chains. Moreover, the ether-based polymer still maintains a certain molecular chain entanglement state and can form an electrolyte and a gel-like substance, improving the cycle characteristics and storage performance of the battery cell.

[0133] In some embodiments, 1 < K1 ≤ 100, and optionally, 1 < K1 ≤ 10. Exemplarily, K1 may be 0.8, 0.9, 1, 2, 5, 10, 15, 20, 30, 50, 100, 200, 500, 1000, 5000, 10000, or a range consisting of any two of the above numerical values.

[0134] In some embodiments, the glass transition temperature of the ether-based polymer is T g2 and the unit is °C, -100 ≤ T g2 ≤ 50, and optionally, -80 ≤ T g2 ≤ 30. Exemplarily, the glass transition temperature of the ether-based polymer may be -100 °C, -80 °C, -60 °C, -30 °C, 0 °C, 30 °C, 50 °C, or a range consisting of any two of the above numerical values.

[0135] In some embodiments, the ether-based polymer includes a structural unit represented by formula (BI),

Chemical formula

[0136] In formula (BI), R 21 and R 22 each independently include a hydrogen atom, a substituted or unsubstituted C1-C3 alkyl group, or a substituted or unsubstituted C1-C3 alkoxy group, R23 comprises a substituted or unsubstituted C1-C5 methylene group, and optionally R 21 and R 22 each independently contain a hydrogen atom, a substituted or unsubstituted C1-C2 alkyl group, and / or R 23 includes a single bond, a substituted or unsubstituted C1-C4 methylene group.

[0137] In some embodiments, when substituted, the substituents may include one or more of a nitrile group (-CN), a nitro group, a sulfonic acid group, a sulfonyl group, an amide group, a carboxyl group, an ester group, or a halogen atom.

[0138] Exemplarily, the ether-based polymer includes at least one of the structural units represented by formula (BI-1) to the structural unit represented by formula (BI-8), [ka]

[0139] In some embodiments, the ether-based polymer comprises a structural unit according to formula (BII): [ka] In formula (BII), R 24 ~R 27 each independently comprises a hydrogen atom, a substituted or unsubstituted C1-C3 alkyl group, a substituted or unsubstituted C1-C3 alkoxy group, or an ether group, and R 24 ~R 27 At least one of the groups contains a substituted or unsubstituted C1-C3 alkoxy or ether group.

[0140] Selectively, R 24 ~R 27 each independently comprises a hydrogen atom, a substituted or unsubstituted C1-C2 alkyl group, a substituted or unsubstituted C1-C2 alkoxy group, or an ether group, and R 24 ~R 27At least one of the groups contains a substituted or unsubstituted C1-C2 alkoxy or ether group.

[0141] In some embodiments, the ether-based polymer comprises at least one of structural units represented by formula (BII-1) to structural units represented by formula (BII-7): [ka]

[0142] The monomers used in the above-mentioned ether polymers are multi-membered rings, for example, six-membered rings or less, or short-chain monomers, which are advantageous for forming a high content of -O- structure upon polymerization. This structural type is advantageous for reducing the degree of entanglement and improving the flexibility of the molecular chains, allowing the molecular chains to spread sufficiently in the electrolyte and easily form a gel material with the electrolyte, thereby improving the cycle characteristics and storage performance of the battery cell.

[0143] The above polymers are merely examples of structural groups in the main molecular chain, and in the embodiments of the present application, the polymer may further be one obtained by copolymerizing the above structural groups with other types of structural groups (e.g., olefin-based structural units, acrylonitrile-based structural units, etc.).

[0144] When the above groups are substituted, the substituents may include one or more of a nitrile group (-CN), a nitro group, a sulfonic acid group, a sulfonyl group, an amide group, a carboxyl group, an ester group, and a halogen atom. The above substituents are pressure-resistant and are further advantageous in stabilizing the polymer structure. The halogen atoms may include fluorine atoms, chlorine atoms, bromine atoms, etc.

[0145] In some embodiments, n is selected from positive integers from 1500 to 25000.

[0146] Optionally, n is selected from a positive integer between 3,000 and 18,000.

[0147] In some embodiments, the molecular weight of the ether-based polymer is 1.2×10 5 g / mol to 1.0×10 6 g / mol.

[0148] Exemplarily, the molecular weight of the ether-based polymer may be 1.2×10 5 g / mol, 2×10 5 g / mol, 5×10 5 g / mol, 8×10 5 g / mol, 1×10 6 g / mol or a range consisting of any two of the above numerical values.

[0149] [Ester-based polymer] In some embodiments, the liquid-affinity polymer includes an ester-based polymer, the ester-based polymer is manufactured into a sheet-like structure, and the sheet-like structure is subjected to a dynamic frequency sweep test at (T m3 +20) °C to obtain a storage modulus G’ - loss modulus G” curve, and the slope of the storage modulus G’ - loss modulus G” curve is K2, where 1 < K2 < ∞, and T m3 represents the melting temperature of the ester-based polymer, with the unit of °C.

[0150] When the ester-based polymer of the embodiment of the present application satisfies the above range, the entanglement state of the molecular chains can be further reduced, which is advantageous for the solvent molecules in the electrolyte to diffuse between the molecular chains. Moreover, the ester-based polymer still maintains a certain molecular chain entanglement state and can form an electrolyte and a gel-like substance, improving the cycle characteristics and storage performance of the battery cell.

[0151] In some embodiments, 1 < K2 ≤ 100, and optionally, 1 < K2 ≤ 10. <​​​​ In some embodiments, the glass transition temperature of the ester-based polymer is T g3 The unit is °C, and -100≦T g3 ≦50, and optionally, −80≦T g3 ≦30.

[0154] For example, the glass transition temperature of the ester-based polymer may be −100° C., −90° C., −80° C., −60° C., −30° C., 0° C., 30° C., 50° C., or a range consisting of any two of the above values.

[0155] In some embodiments, the ester-based polymer comprises a structural unit shown in formula (CI): [ka] In formula (CI), R 31 , R 32 and R 33 each independently comprises a hydrogen atom or a substituted or unsubstituted C1-C8 alkyl group; R 34 comprises a substituted or unsubstituted C1-C8 alkyl group or a substituted or unsubstituted C1-C8 hydroxyalkyl group, optionally R 34 includes a substituted or unsubstituted C1-C6 alkyl group, or a substituted or unsubstituted C1-C6 hydroxyalkyl group.

[0156] Selectively, R 31 contains a hydrogen atom or a substituted or unsubstituted methyl group, and R 32 and R 33 each independently contains a hydrogen atom, and R 34 includes a substituted or unsubstituted C1-C4 alkyl group, or a substituted or unsubstituted C1-C4 hydroxyalkyl group.

[0157] Exemplarily, the ester-based polymer includes at least one of the structural units represented by formula (CI-1) to formula (CI-15): [ka] [ka]

[0158] In some embodiments, the ester-based polymer comprises a structural unit shown in formula (CII): [ka] In formula (CII), R 35 comprises a substituted or unsubstituted C2-C6 methylene group, and optionally R 35 independently comprises a substituted or unsubstituted C2-C4 methylene group.

[0159] Exemplarily, the ester-based polymer includes at least one of the structural units represented by formula (CII-1) to formula (CII-5), [ka]

[0160] The degree of entanglement of the molecular chains of the ester polymer is small, which is advantageous in improving the flexibility of the molecular chains, and the molecular chains spread sufficiently in the electrolyte solution, easily forming a gel substance with the electrolyte solution.

[0161] The above polymers are merely examples of structural groups in the main molecular chain, and in the embodiments of the present application, the polymer may be obtained by copolymerizing the above structural groups with other types of structural groups (for example, olefin-based structural units, acrylonitrile-based structural units, monomers having functional groups such as maleic anhydride).

[0162] When the above groups are substituted, the substituents may include one or more of a nitrile group, a nitro group, a sulfonyl group, a carboxyl group, an ester group, a chlorine atom, a fluorine atom, and a bromine atom, which are pressure-resistant substituents and further advantageous in stabilizing the structure of the polymer.

[0163] In some embodiments, n is selected from positive integers of 800 to 20,000.

[0164] Optionally, n is selected from a positive integer between 1,000 and 15,000.

[0165] In some embodiments, the molecular weight of the ester-based polymer is 1.2×10 5 g / mol to 1.0 × 10 6 g / mol.

[0166] For example, the molecular weight of the ester polymer is 1.2×10 5 g / mol, 2 × 10 5 g / mol, 5 × 10 5 g / mol, 8 × 10 5 g / mol, 1×10 6 g / mol, 1.5 × 10 6 It may be g / mol or a range consisting of any two of the above values.

[0167] [Aldehyde-ketone polymers] In some embodiments, the liquid-philic polymer comprises an aldehyde ketone polymer, and the aldehyde ketone polymer is formed into a sheet-like structure, and the sheet-like structure is (T m4 A dynamic frequency sweep test was performed at +20°C to obtain the elastic modulus G'-loss elastic modulus G" curve, and the slope of the elastic modulus G'-loss elastic modulus G" curve was K3, 0.8 <K3<∞であり、T m4 indicates the melting temperature of the aldehyde ketone polymer, and the unit is °C.

[0168] In some embodiments, 0.8≦K3≦100, and optionally, 0.8≦K3≦10.

[0169] Illustratively, K3 may be 0.8, 0.9, 1, 2, 5, 10, 15, 20, 30, 50, 100, 200, 500, 1000, 5000, 10000, or a range consisting of any two of the above values.

[0170] In some embodiments, the glass transition temperature of the aldehyde ketone polymer is T g4 The unit is °C, and -100≦T g4 ≦50, and optionally, −80≦T g4 ≦30.

[0171] For example, the glass transition temperature of the aldehyde ketone polymer may be −100° C., −90° C., −80° C., −60° C., −30° C., 0° C., 30° C., 50° C., or a range consisting of any two of the foregoing values.

[0172] In some embodiments, the aldehyde ketone polymer comprises a structural unit shown in formula (DI): [ka] In formula (DI), R 41 contains a single bond, a substituted or unsubstituted C1-C6 methylene group, and R 42 contains a hydrogen atom, a substituted or unsubstituted C1-C6 alkyl group, Selectively, R 41 includes a single bond, a substituted or unsubstituted C1-C2 methylene group, Selectively, R 42 includes a hydrogen atom, a substituted or unsubstituted C1-C3 alkyl group.

[0173] In the present embodiment, a single bond means that the group is absent and the atoms on both sides of the group are connected by a single bond, e.g., R 41 is a single bond, R 41 This means that the carbon atoms on both sides of the bond are bonded in the form of a single bond.

[0174] Exemplarily, the aldehyde ketone polymer includes at least one of the structural units represented by formula (DI-1) to formula (DI-6): [ka]

[0175] Illustratively, the aldehyde ketone polymer comprises a structural unit shown in formula (DII): [ka] In formula (DII), R 43 ~R 46 each independently comprises a hydrogen atom, a hydroxyl group, a substituted or unsubstituted C1-C3 alkyl group, a substituted or unsubstituted C1-C3 hydroxyalkyl group, or a substituted or unsubstituted C1-C3 alkoxy group; r and s are each independently selected from integers of 0 to 5, and at least one of r and s is selected from a positive integer; and optionally, R 43 ~R 46 each independently comprises a hydrogen atom, a hydroxyl group, a substituted or unsubstituted C1-C3 alkyl group, a substituted or unsubstituted C1-C2 hydroxyalkyl group, or a substituted or unsubstituted C1-C2 alkoxy group.

[0176] In some embodiments, the aldehyde ketone polymer comprises at least one of structural units shown in formula (DII-1) to structural units shown in formula (DII-4): [ka]

[0177] The degree of entanglement of the molecular chains of the aldehyde ketone polymer is small, which is advantageous for improving the flexibility of the molecular chains, and the molecular chains are advantageous for sufficiently spreading in the electrolyte solution and forming a gel-like substance with the electrolyte solution.

[0178] The above polymers are merely examples of structural groups in the main molecular chain, and in the embodiments of the present application, the polymer may further be one obtained by copolymerizing the above structural groups with other types of structural groups (e.g., olefin-based structural units, enol-based structural units, acrylonitrile-based structural units, etc.).

[0179] When the above groups are substituted, the substituents may include one or more of a nitrile group (-CN), a nitro group, a sulfonyl group, a carboxyl group, an ester group, a chlorine atom, a fluorine atom, and a bromine atom. The above substituents are pressure-resistant substituents, which are further advantageous in stabilizing the structure of the polymer.

[0180] In some embodiments, n is selected from a positive integer between 500 and 15,000.

[0181] Optionally, n is selected from a positive integer between 500 and 10,000.

[0182] In some embodiments, the aldehyde ketone polymer has a molecular weight of 1.2×10 5 g / mol to 1.0 × 10 6 g / mol.

[0183] Illustratively, the molecular weight of the aldehyde ketone polymer is 1.2×10 5 g / mol, 2 × 10 5 g / mol, 5 × 10 5 g / mol, 8 × 10 5 g / mol, 1×10 6 g / mol, 1.0 × 10 6 It may be g / mol or a range consisting of any two of the above values.

[0184] The above polymers are merely examples of structural groups in the main molecular chain, and in the embodiments of the present application, the polymer may be obtained by copolymerizing the above structural groups with small amounts of other types of structural groups (for example, structural units such as olefin-based structural units, ester-based monomers, nitrile-based monomers, and amide-based monomers).

[0185] In the present embodiment, if the liquid-philic polymer further satisfies one or more of the following conditions, the usage reliability and cycle characteristics of the battery cell can be further improved.

[0186] In some embodiments, the liquid-affinity polymer is added to a first solvent at 70°C to form a polymer system, which is then allowed to stand at 70°C for 8 hours and then at 25°C for ≥24 hours. Through two steps of standing, the polymer system undergoes partial swelling and adsorption to transform into a gel-state substance. The polymer system is then filtered through a 200-mesh filter to leave a first substance. The mass of the liquid-affinity polymer is n (g), and the mass of the first substance is m (g). The ratio of the polymer and the first substance satisfies 5≦m / n≦1000, optionally 10≦m / n≦1000, and more optionally 10≦m / n≦50. Exemplarily, m / n may be 5, 10, 20, 25, 28, 30, 32, 35, 40, 50, 80, 100, 200, 500, 1000, or a range consisting of any two of the foregoing values.

[0187] Illustratively, the ratio of the mass content of the liquid-philic polymer to the mass content of the first solvent relative to the mass of the polymer system ranges from 1:100 to 1:10, for example 3:50.

[0188] For example, the first solvent and the electrolyte solvent may be the same or similar, and the first solvent may include a carbonate-based solvent, such as a cyclic carbonate solvent and / or a linear carbonate solvent.

[0189] Taking cyclic carbonate solvents as an example, the cyclic carbonate solvents include one or more of ethylene carbonate (EC), vinylene carbonate (VC), fluoroethylene carbonate (FEC), difluoroethylene carbonate (DFEC), vinylethylene carbonate (VEC), and dioctyl carbonate (CC).

[0190] Taking linear carbonate solvents as an example, the linear carbonate solvents include one or more of dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), diphenyl carbonate (DPC), methyl allyl carbonate MAC, and polycarbonate (PC).

[0191] Alternatively, the first solvent may simultaneously contain a lithium salt and an electrolyte additive, such as lithium hexafluorophosphate, vinylene carbonate (VC), fluoroethylene carbonate (FEC), and the like.

[0192] In this application, m / n is also referred to as the sedimentation value and characterizes the rate at which a lyophilic polymer and solvent are converted into a gel-state material.

[0193] The first substance mainly comprises a gel-state substance formed by a liquid-philic polymer and a first solvent, and in the gel-state substance, the molecular structure of the polymer is essentially unchanged.

[0194] In some embodiments, the first substance is dried at 80° C. for 12 hours, the first solvent in the first substance is removed, and the main component of the dried first substance is the liquid-philic polymer described above, as determined by infrared spectroscopy (IR) or nuclear magnetic resonance (NMR).

[0195] The relevant parameters of the liquid-philic polymers of the present embodiments can be measured using the following methods.

[0196] The hydrophilic polymer groups of the present embodiment can be detected using infrared spectroscopy (IR). Specifically, the hydrophilic polymer was measured using a Thermo Nicolet Nexus 670 Attenuated Total Reflectance Fourier Transform Infrared Spectrometer (FTIR-ATR) in accordance with standard GB / T 6040-2002, with the test range as follows: ATR 600-4000 cm -1 , Reproducibility: ±2cm -1 , resolution: 4cm -1 Superior penetration depth of 0.2~0.6μm.

[0197] The structure of the lyophilic polymer of the present embodiment can be detected using nuclear magnetic resonance (NMR), specifically, 1H NMR and 13C NMR were performed on a Varian Mercury Plus-400 nuclear magnetic resonance instrument, the test temperature was 20°C, TMS was used as the internal standard, CDCl3 was used as the solvent, and the proton resonance frequency was 400 MHz.

[0198] The polymer monomer type of the liquid-philic polymer of the present embodiment (especially applicable to monomers with a small proportion in the polymer) is measured by a combined decomposition-gas chromatography-mass spectrometry, and the specific measurement steps are as follows: 0.5 mg of sample is accurately weighed and placed in a sample cup, which is then attached to a sample rod and placed in a decomposition device attached near the GC (gas chromatography) sample inlet. After the temperature of the decomposition device reaches the set temperature, the sample injection button is pressed and the sample cup rapidly falls into the core of the decomposition furnace by free fall. In an inert gas N2 atmosphere, the volatile components are instantly vaporized and separated by the carrier gas into the gas chromatography column, and finally detected by a flame ionization detector (FID) or mass spectrometer (MS) to obtain a gas chromatogram or total ion chromatogram.

[0199] The molecular weight of the hydrophilic polymer in the embodiment of the present application has a meaning known in the art and can be measured using devices and methods known in the art, such as gel permeation chromatography (GPC). The specific test steps are as follows: Take an appropriate amount of sample to be measured (the sample concentration should be 8%-12% light-shielding), add 20 ml of deionized water, and simultaneously ultrasonicate for 5 minutes (53 KHz / 120 W) to ensure complete dispersion of the sample. Then, measure the sample according to GB / T19077-2016 / ISO 13320:2009 standard.

[0200] Alternatively, the SEC-SAMLL data is measured using a multi-angle light scattering detector (MALLS), specifically, a GPC system using a Dawn Heleos II multi-angle light scattering instrument, an Optilab T-rEX refractive index (RI) detector, and a Visco Star II viscometer (Wyatt Technology Corporation, USA). Measurements are performed at 30°C with tetrahydrofuran as the flow phase at a flow rate of 1.0 ml / min, and the molecular weight parameters are obtained by processing the SEC-SAMLL data using the commercially available software ASTRA6.

[0201] [Positive electrode sheet] The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer provided on the positive electrode current collector, and the positive electrode active material layer includes a positive electrode active material and a liquid-philic polymer.

[0202] As an example, the positive electrode current collector has two surfaces that face each other in the thickness direction of the positive electrode current collector, and the positive electrode active material layer is provided on either one or both of the two facing surfaces of the positive electrode current collector.

[0203] The positive electrode active material layer includes a positive electrode active material, and the positive electrode active material may be any positive electrode active material for battery cells known in the art. For example, the positive electrode active material may include at least one of a lithium-containing phosphate compound, a lithium-containing transition metal oxide, a sodium-containing phosphate compound, and a sodium-containing transition metal oxide material.

[0204] For example, the general formula of an olivine-type phosphate active material (lithium-containing phosphate compound) is Li x A y Me a M b P 1-c X c Y zwhere 0≦x≦1.3, 0≦y≦1.3, and 0.9≦x+y≦1.3. 0.9≦a≦1.5, 0≦b≦0.5, and 0.9≦a+b≦1.5. 0≦c≦0.5, 3≦z≦5. A includes one or more of Na, K, and Mg; Me includes one or more of Mn, Fe, Co, and Ni; M includes one or more of B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, and Ce; X includes one or more of S, Si, Cl, B, C, and N; and Y includes one or more of O and F. Specifically, the olivine-type phosphate active material includes one or more of LiFePO4, LiMnPO4, LiNiPO4, and LiCoPO4.

[0205] Exemplary examples include lithium transition metal oxides (layered materials such as ternary, lithium / sodium nickelate, lithium / sodium cobaltate, lithium / sodium manganate, lithium-rich layered, and rock salt phase layered materials). The general formula for layered cathode active materials is Li x A y Ni a Co b Mn c M (1-a-b-c) Y z where 0≦x≦2.1, 0≦y≦2.1, and 0.9≦x+y≦2.1. 0≦a≦1, 0≦b≦1, 0≦c≦1, and 0.1≦a+b+c≦1, and 1.8≦z≦3.5. A includes one or more of Na, K, and Mg; M includes one or more of B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Fe, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, and Ce; and Y includes one or more of O and F. Optionally, y=0. Specifically, the layered structure positive electrode active material may be lithium cobalt oxide (LCO), lithium nickel oxide (LNO), lithium manganese oxide (LMO), or LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM333), LiNi 0.5 Co 0.2 Mn 0.3O2(NCM523), LiNi 0.6 Co 0.2 Mn 0.2 O2(NCM622), LiNi 0.8 Co 0.1 Mn 0.1 One or more of O2 (NCM811) and NCA may be included.

[0206] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. The metal foil may be, for example, an aluminum foil or an aluminum alloy foil. The composite current collector may include a polymer substrate layer and a metal material layer formed on at least one surface of the polymer substrate layer. For example, the metal material may include one or more combinations selected from aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. The polymer substrate layer may include one or more combinations selected from polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0207] In some embodiments, the positive electrode active material layer may optionally further include a positive electrode conductive agent. The present embodiment does not particularly limit the type of positive electrode conductive agent. For example, the positive electrode conductive agent may include one or more combinations selected from superconducting carbon, conductive carbon black, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the mass percentage of the positive electrode conductive agent is 5% or less with respect to the total mass of the positive electrode active material layer.

[0208] In some embodiments, the positive electrode active material layer may optionally further include a positive electrode binder. The present embodiment does not particularly limit the type of positive electrode binder. For example, the positive electrode binder may include one or more combinations selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene ternary copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene ternary copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylic resin. In some embodiments, the weight percentage of the positive electrode binder is 5% or less, based on the total weight of the positive electrode active material layer. The positive electrode binder has a higher crystallinity than the fluoropolymer of the present embodiment. The positive electrode binder has a higher melting temperature than the fluoropolymer of the present embodiment.

[0209] The positive electrode active material layer is typically formed by applying a positive electrode paste to a positive electrode current collector, drying it, and cold pressing it. The positive electrode paste is typically formed by dispersing a positive electrode active material, a liquid-compatible polymer, an optional conductive agent, an optional binder, and any other components in a solvent and stirring the mixture uniformly. The solvent may be, but is not limited to, N-methylpyrrolidone (NMP). The production of the positive electrode sheet is not limited to the above method, and the production methods described above may also be used.

[0210] [Negative electrode sheet] In some embodiments, the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector and including a negative electrode active material. For example, the negative electrode current collector has two surfaces facing each other in the thickness direction, and the negative electrode active material layer is provided on one or both of the two facing surfaces of the negative electrode current collector.

[0211] The negative electrode active material can be any negative electrode active material for battery cells known in the art. Examples of the negative electrode active material include, but are not limited to, at least one of natural graphite, artificial graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based material can include at least one of silicon elemental, silicon oxide, silicon carbon composite, silicon nitrogen composite, and silicon alloy material. The tin-based material can include at least one of tin elemental, tin oxide, and tin alloy material.

[0212] In some embodiments, the negative electrode active material layer may further include a negative electrode conductive agent. The present embodiment does not particularly limit the type of the negative electrode conductive agent. For example, the negative electrode conductive agent may include at least one of superconducting carbon, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the mass percentage of the negative electrode conductive agent relative to the total mass of the negative electrode active material layer is ≦5%.

[0213] In some embodiments, the negative electrode active material layer may optionally further include a negative electrode binder. The present embodiment does not particularly limit the type of the negative electrode binder. For example, the negative electrode binder may include at least one of styrene butadiene rubber (SBR), water-soluble unsaturated resin (SR-1B), water-soluble acrylic resin (e.g., polyacrylic acid (PAA), polymethacrylic acid (PMAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS). In some embodiments, the weight percent of the negative electrode binder is ≦5% relative to the total weight of the negative electrode active material layer.

[0214] In some embodiments, the negative electrode active material layer may optionally further include other additives. For example, the other additives may include a thickener, such as sodium carboxymethyl cellulose (CMC), a PTC thermistor material, etc. In some embodiments, the weight percentage of the other additives relative to the total weight of the negative electrode active material layer is ≦2%.

[0215] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, the metal foil may be copper foil. The composite current collector may include a polymer substrate layer and a metal material layer formed on at least one surface of the polymer substrate layer. For example, the metal material may include at least one of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. For example, the polymer substrate layer may include at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0216] The negative electrode active material layer is typically formed by applying a negative electrode paste to a negative electrode current collector, drying it, and cold-pressing it. The negative electrode paste is typically formed by dispersing a negative electrode active material, a liquid-compatible polymer, an optional conductive agent, an optional binder, and other optional auxiliary agents in a solvent and stirring the mixture uniformly. The solvent may be, but is not limited to, N-methylpyrrolidone (NMP) or deionized water. The production of the negative electrode sheet is not limited to the above method, and the production methods described above may also be used.

[0217] The negative electrode sheet does not exclude additional functional layers other than the negative electrode active material layer. For example, in some embodiments, the negative electrode sheet described herein further includes a conductive primer layer (e.g., composed of a conductive agent and a binder) sandwiched between the negative electrode current collector and the negative electrode active material layer and provided on the surface of the negative electrode current collector. In some other embodiments, the negative electrode sheet described herein further includes a protective layer covering the surface of the negative electrode active material layer.

[0218] [Separator] The separator includes a substrate and a coating layer provided on at least one surface of the substrate.

[0219] For example, the substrate generally has a porous structure, in which voids exist, and the liquid-philic polymer is distributed in the voids of the substrate.

[0220] In another example, the liquid-philic polymer may be distributed within the coating layer.

[0221] In yet another example, the liquid-philic polymer may be provided on the surface of the coating layer opposite to the substrate.

[0222] The specific distribution position of the liquid-philic polymer may be any one of the above three types, any two of them, or a combination of the above three types.

[0223] The present embodiment does not particularly limit the material of the substrate, and any known substrate having good chemical and mechanical stability, such as at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride, can be selected. The substrate may be a single-layer film or a multilayer composite film. When the substrate is a multilayer composite film, the materials of each layer may be the same or different. The substrate generally has a porous structure, in which voids exist, and the liquid-philic polymer is distributed in the voids of the substrate.

[0224] In some embodiments, the coating layer may further include a filler. Further, the filler may include at least one of inorganic particles and organic particles. The liquid-philic polymer may be distributed within the coating layer.

[0225] In some embodiments, a liquid-philic polymer may be provided on the surface of the coating layer opposite the substrate.

[0226] In some embodiments, the decomposition temperature of the filler may be 200°C or higher, which gives the filler excellent thermal stability and resistance to decomposition, thereby further improving the heat resistance of the separator.

[0227] The inorganic particles have high thermal stability and are resistant to decomposition. Optionally, the inorganic particles include at least one of inorganic particles having a dielectric constant of 5 or more, inorganic particles having ionic conductivity but not storing ions, and inorganic particles capable of generating electrical and chemical reactions.

[0228] Alternatively, the inorganic particles having a dielectric constant of 5 or more may be any of inclusive boehmite, aluminum oxide, zinc oxide, silicon oxide, titanium oxide, zirconium oxide, barium oxide, calcium oxide, magnesium oxide, nickel oxide, tin oxide, cerium oxide, yttrium oxide, hafnium oxide, aluminum hydroxide, magnesium hydroxide, silicon carbide, boron carbide, aluminum nitride, silicon nitride, boron nitride, magnesium fluoride, calcium fluoride, barium fluoride, barium sulfate, magnesium aluminum silicate, magnesium lithium silicate, magnesium sodium silicate, bentonite, hectorite, zirconium titanate, barium titanate, Pb(Zr,Ti)O3 (abbreviated as PZT), Pb 1-m La m Zr 1-n Ti n O3 (abbreviated as PLZT, 0 <m<1、0<n<1)、Pb(Mg3Nb 2 / 3The coating composition includes at least one of the following: )O3-PbTiO3 (abbreviated as PMN-PT), and modified inorganic particles. Optionally, the modification method of each inorganic particle may be chemical and / or physical. Chemical modification methods include coupling agent modification (e.g., the use of silane coupling agents, titanate ester coupling agents, etc.), surfactant modification, and polymer graft modification. Physical modification methods may include mechanical dispersion, ultrasonic dispersion, high-energy treatment, etc. The modification treatment can reduce the aggregation of inorganic particles, thereby enabling the construction and formation of a more stable and uniform spatial network structure with nanocellulose. Furthermore, selecting coupling agents, surface active materials, or polymer-modified inorganic particles with specific functional groups can further improve the wetting properties of the coating layer against the electrolyte and help improve the adhesive strength between the coating layer and the substrate.

[0229] Optionally, the inorganic particles that are ionically conductive but do not store ions are Li3PO4, lithium titanium phosphate Li x1 Ti y1 (PO4)3, Lithium titanium aluminum phosphate Li x2 Al y2 Ti z1 (PO4)3, (LiAlTiP) x3 O y3 Lithium lanthanum titanate glass x4 La y4 TiO3, Lithium germanium thiophosphate Li x5 Ge y5 P z2 S w , lithium nitride Li x6 N y6 , SiS2-based glass Li x7 Si y7 S z3 and P2S5-based glass Li x8 P y8 S z4including at least one of them, where 0 < x1 < 2, 0 < y1 < 3, 0 < x2 < 2, 0 < y2 < 1, 0 < z1 < 3, 0 < x3 < 4, 0 < y3 < 13, 0 < x4 < 2, 0 < y4 < 3, 0 < x5 < 4, 0 < y5 < 1, 0 < z2 < 1, 0 < w < 5, 0 < x6 < 4, 0 < y6 < 2, 0 < x7 < 3, 0 < y7 < 2, 0 < z3 < 4, 0 < x8 < 3, 0 < y8 < 3, 0 < z4 < 7. Thereby, the ion transport characteristics of the separator can be further improved.

[0230] Since the organic particles have excellent thermal stability and are difficult to decompose, the heat resistance of the separator can be improved. At the same time, when the internal temperature of the battery cell reaches the melting point of the organic particles due to overcharging abuse, thermal abuse, etc., the organic particles can further melt and be sucked into the pores of the substrate by capillary action to play a role in closing the pores and closing the circuit, which is advantageous for ensuring the high safety performance of the battery cell.

[0231] In some embodiments, the organic particles include, but are not limited to, one or more of polyethylene particles, polypropylene particles, polystyrene particles, melamine resin particles, phenol resin particles, polyester particles (such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate), polyimide particles, polyamideimide particles, polyaramide particles, polyphenylene sulfide particles, polysulfone particles, polyether sulfone particles, polyether ether ketone particles, polyaryl ether ketone particles, copolymers of butyl acrylate and ethyl methacrylate (such as cross-linked polymers of butyl acrylate and ethyl methacrylate).

[0232] In some embodiments, the coating layer further comprises a binder. The present application does not particularly limit the type of binder, and any known material having good adhesive properties can be selected. As an example, the binder includes at least one of a water-soluble acrylic resin (e.g., a homopolymer of acrylic acid, methacrylic acid, or sodium acrylate monomer or a copolymer with other comonomers), polyvinyl alcohol, an isobutylene-maleic anhydride copolymer, and polyacrylamide.

[0233] Optionally, the content of the binder in the coating layer is <30% based on the weight of the coating layer.

[0234] [Electrolyte] During the charge and discharge process of the battery cell, active ions are inserted and removed between the positive electrode sheet and the negative electrode sheet, and the electrolyte serves to conduct the active ions between the positive electrode sheet and the negative electrode sheet. The present application does not particularly limit the type of electrolyte, and it can be selected according to actual needs.

[0235] The electrolyte solution includes an electrolyte salt and a solvent, and the types of the electrolyte salt and the solvent are not specifically limited and can be selected according to actual needs.

[0236] When the battery cell of the present application is a lithium-ion battery, for example, the electrolyte salt may include at least one of lithium hexafluorophosphate (LiPF), lithium tetrafluoroborate (LiBF), lithium perchlorate (LiClO), lithium hexafluoroarsenate (LiAsF), lithium bisfluorosulfonylimide (LiFSI), lithium bistrifluoromethanesulfonylimide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalatoborate (LiDFOB), lithium bisoxalatoborate (LiBOB), lithium difluorophosphate (LiPOF), lithium difluorobisoxalatophosphate (LiDFOP), and lithium tetrafluorooxalatophosphate (LiTFOP), but is not limited thereto.

[0237] When the battery cell of the present application is a sodium-ion battery, for example, the electrolyte salt may include at least one of sodium hexafluorophosphate (NaPF), sodium tetrafluoroborate (NaBF), sodium perchlorate (NaClO), sodium hexafluoroarsenate (NaAsF), sodium bisfluorosulfonylimide (NaFSI), sodium bistrifluoromethanesulfonylimide (NaTFSI), sodium trifluoromethanesulfonate (NaTFS), sodium difluorooxalatoborate (NaDFOB), sodium bisoxalatoborate (NaBOB), sodium difluorophosphate (NaPOF), sodium difluorobisoxalatophosphate (NaDFOP), and sodium tetrafluorooxalatophosphate (NaTFOP), but is not limited thereto.

[0238] By way of example, the solvent may include, but is not limited to, one or more of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), methylsulfonylmethane (MSM), ethyl methanesulfonate (EMS), and diethylsulfone (ESE).

[0239] In some embodiments, the electrolyte solution optionally further contains additives. For example, the additives may include a negative electrode film-forming additive, a positive electrode film-forming additive, and additives that can improve specific battery performance, such as an additive that improves the overcharge characteristics of the battery, an additive that improves the high-temperature characteristics of the battery, or an additive that improves the low-temperature power output characteristics of the battery.

[0240] In some embodiments, an electrode assembly can be manufactured from the positive electrode sheet, the separator, and the negative electrode sheet through a winding process and / or a stacking process.

[0241] In some embodiments, the battery cell may include a housing material that is used to encapsulate the electrode assembly and the electrolyte.

[0242] In some embodiments, the battery cell exterior may be a hard case such as a hard plastic case, an aluminum case, or a steel case. The battery cell exterior may be a soft pack such as a pouch-type soft pack. The soft pack may be made of plastic, such as at least one of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0243] In some embodiments, the positive electrode sheet, separator, and negative electrode sheet can be fabricated into an electrode assembly via a winding or lamination process.

[0244] The present application does not particularly limit the shape of the battery cell, and it may be cylindrical, rectangular, or any other shape. Figure 1 shows a battery cell 5 with a rectangular structure as an example.

[0245] In some embodiments, as shown in FIGS. 1 and 2 , the exterior material may include a housing 51 and a cover plate 53. The housing 51 may include a bottom plate and side plates connected to the bottom plate, forming a storage cavity surrounded by the bottom plate and side plates. The housing 51 has an opening communicating with the storage cavity, and the cover plate 53 is used to cover the opening and seal the storage cavity. The positive electrode sheet, the negative electrode sheet, and the separator may form an electrode assembly 52 through a winding process or a stacking process. The electrode assembly 52 is sealed in the storage cavity. An electrolyte is impregnated in the electrode assembly 52. ​​The number of electrode assemblies 52 included in the battery cell 5 may be one or more and can be adjusted as needed.

[0246] The manufacturing method of the battery cell of the present application is well known. In some embodiments, a battery cell can be formed by assembling a positive electrode sheet, a separator, a negative electrode sheet, and an electrolyte. For example, an electrode assembly can be formed from the positive electrode sheet, the separator, and the negative electrode sheet through a winding process or a stacking process. The electrode assembly can then be placed in a housing, dried, and then injected with an electrolyte. The battery cell can then be obtained through processes such as vacuum sealing, standing, chemical conversion, and shaping.

[0247] In some embodiments of the present application, the battery cells of the present application can be assembled into a battery module, and the battery module may include multiple battery cells, the specific number of which can be adjusted according to the application and capacity of the battery module.

[0248] FIG. 3 is a schematic diagram of an example battery module 4. As shown in FIG. 3, in the battery module 4, a plurality of battery cells 5 can be arranged in sequence along the length of the battery module 4. Of course, any other arrangement may also be used. The plurality of battery cells 5 can also be fastened together using fasteners.

[0249] Optionally, the battery module 4 may further include an outer case having an accommodating space for accommodating the plurality of battery cells 5.

[0250] In some embodiments, the battery modules can be further assembled into a battery pack, and the number of battery modules included in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0251] The battery module 4 and the battery pack can both be specific examples of the battery in the embodiments of the present application.

[0252] 4 and 5 are schematic diagrams of an example battery pack 1. As shown in FIGS. 4 and 5, the battery pack 1 can include a battery case and a plurality of battery modules 4 provided in the battery case. The battery case includes an upper housing 2 and a lower housing 3, and the upper housing 2 is used to cover the lower housing 3 and forms a sealed space for accommodating the battery modules 4. The plurality of battery modules 4 can be arranged in the battery case in any manner.

[0253] power consumption equipment According to a second aspect, the present application provides a power consuming device including at least one of a battery cell, a battery module, or a battery pack according to the present application. The battery cell, the battery module, and the battery pack may be used as a power source for the power consuming device or as an energy storage element for the power consuming device. The power consuming device may be, but is not limited to, a mobile device (e.g., a mobile phone, a laptop, etc.), an electric vehicle (e.g., 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.), a train, a ship, a satellite, an energy storage system, etc. In some embodiments, the battery cell includes a fill hole for injecting electrolyte, and when the battery cell is applied to the power consuming device, the fill hole is located at the bottom along the vertical direction of the battery cell. Because the amount of free electrolyte in the battery cell is very small, or even absent, providing the fill hole at the bottom along the vertical direction of the battery cell can also improve the reliability of the battery cell and the power consuming device.

[0254] A power consuming device can be configured as a battery cell, a battery module, or a battery pack depending on its usage conditions. FIG. 6 is a schematic diagram of an example power consuming device. The power consuming device 6 may be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of the power consuming device, a battery pack 1 or a battery module may be used. Another example power consuming device may be a mobile phone, a tablet computer, a laptop computer, etc. The power consuming device is generally required to be lightweight and thin, and can use a battery cell as a power source.

[0255] Example Examples of the present application are described below. The examples described below are illustrative and are intended only to explain the present application and should not be understood as limitations on the present application. If specific techniques or conditions are not specified in the examples, they will be carried out according to techniques or conditions described in literature in the field or according to product specifications. If the manufacturer of the reagents or equipment used is not specified, they are all commercially available general products.

[0256] Example 1: Manufacture of a lithium-ion battery (1) Manufacturing of positive electrode sheet: The positive electrode current collector is an aluminum foil with a thickness of 12 μm.

[0257] Liquid-compatible polymer, LiNi positive electrode active material 0.6 Co 0.2 Mn 0.2 The positive electrode paste was prepared by mixing O2 (NCM622), the conductive agent carbon black, and the binder polyvinylidene fluoride (PVDF) with N-methylpyrrolidone (NMP). The mass ratio of the liquid-compatible polymer (NCM622), conductive carbon black, PVDF, and N-methylpyrrolidone (NMP) in the positive electrode paste was 0.5:96.8:2.2:0.5. The positive electrode paste was applied to an aluminum foil current collector, dried at 85°C, cold-pressed, trimmed, cut, and slit, and then dried under vacuum at 85°C for 4 hours to produce a positive electrode sheet.

[0258] (2) Manufacturing of negative electrode sheet: A copper foil with a thickness of 8 μm is used as the negative electrode current collector.

[0259] The negative electrode paste is prepared by adding a liquid-compatible polymer, artificial graphite (negative electrode active material), carbon black (conductive agent), styrene butadiene rubber (SBR) (binder), and sodium carboxymethyl cellulose (CMC) (thickener) to water in a weight ratio of 2.5:94.9:2:0.5:0.1 and mixing evenly. The negative electrode paste is applied to a copper foil current collector and dried at 85°C. After that, the foil is cold pressed, trimmed, cut, and slit, and then dried at 120°C under vacuum for 12 hours to produce a negative electrode sheet.

[0260] (3) Electrolyte production: In an environment with a water content of less than 10 ppm, the non-aqueous organic solvents ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed in a volume ratio of 3:7 to obtain an electrolyte solvent, and then the resulting solvent is mixed with lithium salt LiPF6 to prepare an electrolyte with a lithium salt concentration of 1 mol / L.

[0261] (4) Lithium-ion battery manufacturing: A 16 μm polyethylene film (PE) was used as the separator substrate, and a polymer coating layer was applied to the surface of the substrate. The mass contents of the ordinary polyvinylidene fluoride (PVDF) and binder styrene butadiene rubber (SBR) in the polymer coating layer were 85% and 15%, respectively.

[0262] The positive electrode sheet, separator, and negative electrode sheet are stacked in this order (the separator serves to separate the positive and negative electrode sheets), and then wound to obtain an electrode assembly. The electrode assembly is placed in a housing, dried, and then an electrolyte is injected. After vacuum sealing, standing, chemical formation, shaping, and other processes, a lithium-ion battery is obtained.

[0263] Comparative Example 1 A lithium ion battery was manufactured in the same manner as in Example 1, except that no liquid-affinity polymer was added to the positive electrode paste of Comparative Example 1, and no liquid-affinity polymer was added to the negative electrode paste.

[0264] Examples 2-1 to 2-4 Lithium ion batteries were produced in the same manner as in Example 1, except that Examples 2-1 to 2-4 differed from Example 1 in that the amount of liquid-philic polymer added to the negative electrode paste was adjusted.

[0265] Examples 3-1 to 3-4 Lithium ion batteries were produced in the same manner as in Example 1, except that in Examples 3-1 to 3-4, the amount of electrolyte injected was adjusted.

[0266] Examples 4-1 to 4-4 Lithium ion batteries were produced in the same manner as in Example 1, except that Examples 4-1 to 4-4 differed from Example 1 in that the type of liquid-philic polymer was adjusted.

[0267] Examples 5-1 to 5-3 Lithium ion batteries were manufactured in the same manner as in Example 1, except that the placement position of the liquid-compatible polymer in Examples 5-1 to 5-3 was adjusted, and the mass content of polycarbosilane (PCS) in Example 5-3 was 80%, the mass content of the liquid-compatible polymer was 10%, and the mass content of the binder was 10%.

[0268] The data for the examples and comparative examples are shown in Table 1.

[0269] Exam section 1. Lithium-ion battery cycle characteristic test At 25±2°C, the lithium ion batteries manufactured in the examples and comparative examples were charged at a rate of 1C and discharged at a rate of 1C, and a full charge / full discharge cycle test was performed until the capacity of the secondary battery was reduced to 80% of the initial capacity. The test was then stopped and the number of cycles was recorded.

[0270] 2. Lithium-ion battery module vibration test The lithium-ion batteries manufactured in the examples and comparative examples were charged to 100% SOC at 0.5C (i.e., a current of 0.5 times the capacity rate) at 25±2°C and then allowed to stand for 1 hour. A 2mm diameter hole was drilled in the bottom of the cell to simulate cell leakage. Twelve cells were connected in series to form a group, with one end of the module connected to the negative electrode of the module and the other end semi-contacting / contacting the end plate. A voltage of 200V was applied externally and observed for 1 hour (the breaker was turned off if a fire occurred). The presence or absence of insulation failure and the duration of the fire were confirmed.

[0271] [Table 1]

[0272] In Table 1, VDF refers to vinylidene fluoride, HFP refers to hexafluoropropylene, and TFE refers to tetrafluoroethylene. 80%VDF+15%HFP+5%TFE indicates that the mass percent content of VDF is 80%, the mass percent content of HFP is 15%, and the mass percent content of TFE is 5%, based on the total mass of all monomers.

[0273] The nominal capacity x of the batteries of the comparative example and the example is 151 Ah.

[0274] [Table 2]

[0275] As can be seen from Tables 1 and 2, the positive electrode sheet and the negative electrode sheet of Comparative Example 1 did not contain a liquid-compatible polymer. During the cycling process of the lithium ion battery, the volume of the lithium ion battery changes, which may cause the electrolyte in the electrode assembly to be pushed out, resulting in a liquid shortage problem. This increases the risk of lithium dendrites appearing, and reduces the usage reliability and cycling characteristics of the lithium ion battery.

[0276] In the present embodiment, by adding a liquid-compatible polymer to at least one of the positive electrode sheet, the negative electrode sheet, and the separator, the liquid-compatible polymer can form a gel electrolyte with the electrolyte, improving the liquid retention capacity and thereby improving the usage reliability and cycle characteristics of the lithium-ion battery.

[0277] Although the present application has been described with reference to preferred embodiments, various modifications may be made and equivalents may be substituted for the components thereof without departing from the scope of the present application. In particular, as long as there is no structural contradiction, the technical features recited in each embodiment may be combined in any manner. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell including an electrode assembly and an electrolyte, The electrode assembly includes a first polar sheet, a second polar sheet, and a separator, the first polar sheet and the second polar sheet having opposite polarities, the separator being disposed between the first polar sheet and the second polar sheet, and at least one of the first polar sheet, the second polar sheet, and the separator includes a liquid-philic polymer, and the battery cell has a structure represented by the following formula: [Equation 1] Fulfilling y represents the mass of free electrolyte in the battery cell, expressed in g; M represents the mass of the battery cell before drying, in g; M' represents the mass of the battery cell after drying, and is expressed in g. 【Request Item 2】 【Number 2】 and Selectively, [Equation 3] The battery cell according to claim 1 ,

3. The battery cell further has the formula: [Equation 4] and / or [Equation 5] Fulfilling m １ represents the mass of the electrode assembly before drying, in g; m ２ The battery cell according to claim 1 or 2, wherein m represents the mass of the electrode assembly after drying, and the unit is g.

4. The amount of free electrolyte per unit capacity of the battery cell is b, expressed in mg / Ah, and 0≦b≦1400; The battery cell according to any one of claims 1 to 3, wherein optionally, 0.1≦b≦1000, and further optionally, 0.3≦b≦800.

5. the first polar sheet includes a current collector and an active material layer provided on at least one surface of the current collector, the active material layer including the liquid-philic polymer and active material particles; the liquid-philic polymer is distributed on the surface of the active material particles, and / or 5. The battery cell according to claim 1, wherein the active material particles are a plurality of particles, and a gap is formed between two adjacent active material particles, and the liquid-affinity polymer is distributed in the gap between the active material particles.

6. the separator includes a substrate and a coating layer provided on at least one surface of the substrate; The liquid-philic polymer is distributed in the voids of the substrate, and / or the liquid-philic polymer is distributed within the coating layer; and / or The battery cell according to any one of claims 1 to 5, wherein the liquid-philic polymer is provided on a surface of the coating layer opposite to the substrate.

7. the liquid-philic polymer comprises a fluoropolymer; The crystallinity of the fluoropolymer measured by differential scanning calorimetry is Xc １ and 0<Xc １ ≦30%; The melting temperature of the fluoropolymer is T ｍ１ and the unit is ° C., and 0<T ｍ１ 7. The battery cell according to claim 1, wherein the resistance is ≦140.

8. The glass transition temperature of the fluoropolymer is T ｇ１ The unit is °C, and −150≦T ｇ１ 8. The battery cell of claim 7, wherein the .lambda.

9. The fluoropolymer comprises at least one of structural units represented by formula (AI) to structural units represented by formula (AIII), 【Chemistry 1】 In formula (AI) and formula (AII), R １１ , R １２ , R １３ and R １４ each independently comprises a hydrogen atom, a fluorine atom, a chlorine atom, a substituted or unsubstituted C1-C3 alkyl group, or a substituted or unsubstituted C1-C3 alkoxy group, and R １１ , R １２ , R １３ and R １４ at least one of the groups contains a fluorine atom, and when substituted, the substituents contain one or more of a nitrile group (—CN), a nitro group, a sulfonic acid group, a sulfonyl group, an amide group, a carboxyl group, an ester group, and a halogen atom; 【Chemistry 2】 In formula (AIII), R １５ comprises a single bond, a substituted or unsubstituted C1-C3 alkyl group, and if substituted, the substituent comprises one or more of a nitrile group (—CN), a nitro group, a sulfonic acid group, a sulfonyl group, an amide group, a carboxyl group, an ester group, and a halogen atom; p is selected from a positive integer of 1 to 3; and n is selected from a positive integer of 1,000 to 30,000.

10. The liquid-compatible polymer further includes an ether-based polymer, and the ether-based polymer is formed into a sheet-like structure, and the sheet-like structure is (T ｍ２ A dynamic frequency sweep test was performed at 20°C to obtain a modulus of elasticity G'-loss modulus of elasticity G" curve, and the slope of the modulus of elasticity G'-loss modulus of elasticity G" curve was K １ and 1<K １ <∞, and T ｍ２ represents the melting temperature of the ether-based polymer, in ° C.; optionally, 1<K １ ≦100, and further optionally, 1<K １ 10. The battery cell according to claim 1, wherein the resistance of the battery cell is ≦10.

11. The ether-based polymer contains a structural unit represented by formula (BI) and / or a structural unit represented by formula (BII), 【Transformation 3】 In formula (BI), R ２１ and R ２２ each independently comprises a hydrogen atom, a substituted or unsubstituted C1-C3 alkyl group, or a substituted or unsubstituted C1-C3 alkoxy group; R ２３ comprises a substituted or unsubstituted C1-C5 alkylene group; 【Chemistry 4】 In formula (BII), R ２４ ~R ２７ each independently comprises a hydrogen atom, a substituted or unsubstituted C1-C3 alkyl group, a substituted or unsubstituted C1-C3 alkoxy group, or an ether group, and R ２４ ~R ２７ 11. The battery cell of claim 10, wherein at least one of comprises a substituted or unsubstituted C1-C3 alkoxy or ether group.

12. The liquid-compatible polymer includes an ester-based polymer, and the ester-based polymer is formed into a sheet-like structure. The sheet-like structure is (T ｍ３ A dynamic frequency sweep test was performed at 20°C to obtain a modulus of elasticity G'-loss modulus of elasticity G" curve, and the slope of the modulus of elasticity G'-loss modulus of elasticity G" curve was K ２ and 1<K ２ <∞, and T ｍ３ represents the melting temperature of the ester polymer, in ° C.; optionally, 1<K ２ ≦100, and further optionally, 1<K ２ 12. The battery cell according to claim 1, wherein the resistance is ≦10.

13. The ester-based polymer contains a structural unit represented by formula (CI) and / or a structural unit represented by formula (CII), 【Transformation 5】 In formula (CI), R ３１ , R ３２ and R ３３ each independently comprises a hydrogen atom or a substituted or unsubstituted C1-C8 alkyl group; R ３４ comprises a substituted or unsubstituted C1-C8 alkyl group or a substituted or unsubstituted C1-C8 hydroxyalkyl group; 【Transformation 6】 In formula (CII), R ３５ comprises a substituted or unsubstituted C2-C6 methylene group, and optionally R ３５ and independently comprise a substituted or unsubstituted C2-C4 methylene group.

14. The liquid-compatible polymer includes an aldehyde ketone polymer, and the aldehyde ketone polymer is formed into a sheet-like structure, and the sheet-like structure is (T ｍ４ A dynamic frequency sweep test was performed at 20°C to obtain a modulus of elasticity G'-loss modulus of elasticity G" curve, and the slope of the modulus of elasticity G'-loss modulus of elasticity G" curve was K ３ and 0.8≦K ３ <∞, and T ｍ４ represents the melting temperature of the aldehyde ketone polymer, in ° C.; optionally, 0.8<K ３ ≦100, and more optionally, 0.8<K ３ 14. The battery cell according to claim 1, wherein the resistance is ≦10.

15. The aldehyde ketone polymer comprises a structural unit represented by formula (DI) and / or a structural unit represented by formula (DII), 【Transformation 7】 In formula (DI), R ４１ contains a single bond, a substituted or unsubstituted C1-C6 methylene group, and R ４２ contains a hydrogen atom, a substituted or unsubstituted C1-C6 alkyl group, 【Transformation 8】 In formula (DII), R ４３ ~R ４６ each independently comprise a hydrogen atom, a hydroxyl group, a substituted or unsubstituted C1-C3 alkyl group, a substituted or unsubstituted C1-C3 hydroxyalkyl group, or a substituted or unsubstituted C1-C3 alkoxy group; r and s are each independently selected from integers of 0 to 5, and at least one of r and s is selected from a positive integer.

16. The molecular weight of the liquid-affinity polymer is 1.2×10 ５ g / mol to 1 x 10 ６ The battery cell according to any one of claims 1 to 15, wherein the electrical conductivity is 100 kJ / mol.

17. A battery comprising the battery cell according to any one of claims 1 to 16.

18. 20. A power consuming device comprising the battery of claim 17.

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