Electrode sheet, battery and power consumption device

Abstract

This application relates to an electrode sheet, a battery, and a power consuming device. The electrode sheet comprises a current collector and a film layer containing an active material and an adsorbent polymer, disposed on at least one side of the current collector. The adsorbent polymer was added to a predetermined electrolyte solution at 45°C to form a polymer system. The polymer system was allowed to stand at 45°C for 60 hours, then at 25°C for at least 24 hours, and then filtered through a 200-mesh filter. The remaining filtrate was designated as a first substance, with the mass n of the adsorbent polymer in grams, the mass m1 of the first substance in grams, and the ratio of the adsorbent polymer and the first substance satisfying 3≦m1 / n≦35. The first substance was then dried at 60°C for at least 24 hours to obtain a second substance, with the mass m2 of the second substance in grams, and the ratio of the second substance and the first substance satisfying 1.00≦m2 / n≦1.05.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to Chinese Patent Application No. 202311457180.1, entitled "Electrode Sheet, Battery and Power Consumption Device," filed on November 3, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the field of battery technology, and in particular to electrode sheets, battery cells, batteries, and power consuming devices. [Background technology]

[0003] Due to their characteristics such as high capacity and long life, batteries are widely used in electronic devices such as mobile phones, laptops, electric bicycles, electric cars, electric airplanes, electric boats, electric toy cars, electric toy boats, electric toy airplanes, and power tools.

[0004] As batteries are applied in more and more fields, the requirements for their performance are becoming more and more stringent, and there is a need for further improvement in the cycle performance of batteries. Summary of the Invention

[0005] The present application has been made in view of the above-mentioned problems, and aims to provide an electrode sheet, a battery, and a power consuming device.

[0006] A first aspect of the present application provides a battery comprising: a current collector; and a film layer provided on at least one side of the current collector, the film layer including an active material and an adsorptive polymer; At 45°C, an adsorbent polymer is added to a predetermined electrolyte solution to form a polymer system, the mass ratio of the predetermined electrolyte solution to the adsorbent polymer is 1:15, the predetermined electrolyte solution includes dimethyl carbonate, ethyl methyl carbonate, ethylene carbonate, and lithium hexafluorophosphate, the dimethyl carbonate, ethyl methyl carbonate, and ethylene carbonate are equal in mass, and the concentration of lithium hexafluorophosphate is 1 mol / L; The polymer system is allowed to stand at 45°C for 60 hours, and then allowed to stand at 25°C for 24 hours or more, and then filtered through a 200-mesh filter. The remaining filtrate is the first substance, and the mass n of the adsorbent polymer is g, and the mass m1 of the first substance is g, and the adsorbent polymer and the first substance satisfy 3≦m1 / n≦35; After drying the first material at 60°C for 24 hours or more, a second material is obtained, and the mass m2 of the second material is expressed in g, and the second material and the first material satisfy 1.00≦m2 / n≦1.05, thereby providing an electrode sheet.

[0007] Thus, in an embodiment of the present application, the process of the adsorbent polymer physically adsorbing the electrolyte is reversible. When the system temperature is somewhat high, for example, at the high normal operating temperature of the battery system, the adsorbent polymer can form an in-situ gel-like substance by promoting attraction and physical bonding between the adsorbent polymer molecular chains and the solvent while allowing the molecular chains to expand. On the other hand, when the system temperature drops to the low normal operating temperature of the battery system, the in-situ gel-like substance adheres to the surface of the active material particles, locking the electrolyte in the space or environment where the adsorbent polymer is present, protecting the active material interface and contributing to the normal transport of lithium ions. Furthermore, when the system temperature is higher, for example, at the higher normal operating temperature of the battery system, or in a dry or other liquid-starved environment, the locked electrolyte can be released, realizing flexible electrolyte storage. When the active particles expand and deform during charge and discharge, the gelled absorbent polymer releases the liquid electrolyte in a timely manner, buffering deformation at the interface between the polymer and the active particles, thereby improving the cycle performance of the battery.

[0008] In some embodiments, 5≦m1 / n≦35.

[0009] In some embodiments, the mass content of the adsorbent polymer is 5% or less, optionally 0.05% to 5%, based on the total mass of the film layer, and / or the coating weight of the adsorbent polymer is 0.5 mg / 1540.25 mm 2 ~2mg / 1540.25mm 2 When the content of the adsorbent polymer is within the above range, the adsorbent polymer can effectively improve the interface performance and structural stability of the electrode sheet.

[0010] In some embodiments, the adsorbent polymer comprises a fluoropolymer, and the fluoropolymer has a crystallinity, X, by differential scanning calorimetry. c1 (%) is 0 <X c1 ≦30, Fluoropolymer melting temperature T m1 (℃) is 0 <T m1 ≦140, More selectively, the glass transition temperature T g1 (℃) is -150≦T g1 ≦60, Further optionally, the fluoropolymer comprises at least one of the compounds represented by formula (AI) to (AIII), [ka] In formula (AI) and formula (AII), R 11 , R 12 , R 13 and R 14 each independently contains a hydrogen atom, a fluorine atom, a chlorine atom, a bromine 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; [ka] In formula (AIII), R 15includes a single bond, a substituted or unsubstituted C1-C3 alkyl group, p is selected from any positive integer from 1 to 3, and n is selected from any positive integer from 1000 to 30000.

[0011] In this way, the fluoropolymer has a lower crystallinity, melting temperature or glass transition temperature, the flexibility of the molecular chains of the fluoropolymer is improved, and accordingly, the segments of the molecular chains become more flexible, the adjacent molecular chains are more easily broken, the solvent molecules in the electrolyte enter between the molecular chains of the fluoropolymer to form a gel-like substance, whereby the electrolyte is effectively stored on the surface of the active material and the wettability to the active material is improved. Since the gel-like substance can release the solvent molecules and return to the polymer state at high temperatures, it has a certain degree of elasticity, and the interface between the fluoropolymer and the active material particles can be deformed, so that it can be deformed during the charge and discharge cycles of the battery, reducing the risk of the internal structure of the electrode sheet peeling off, improving the structural stability of the entire electrode sheet, and improving the cycle performance of the battery cell.

[0012] In some embodiments, the adsorbent polymer includes an ether-based polymer. For the sheet-like structure produced from the ether-based polymer, an elastic modulus G'-loss elastic modulus G'' curve is obtained by a dynamic frequency scanning test at (T m2 + 20) °C, and the slope K1 of the elastic modulus G'-loss elastic modulus G'' curve is 1 < K1 < ∞, where T m2 (°C) represents the melting temperature of the ether-based polymer. Optionally, 1 < K1 ≤ 100, and further optionally, 1 < K1 ≤ 10. Optionally, the glass transition temperature T g2 (°C) of the ether-based polymer is -100 ≤ T g2 ≤ 50, and optionally, -80 ≤ T g2 ≤ 30. Further optionally, the ether-based polymer includes at least one of the compound represented by formula (BI) and the compound represented by formula (BII).

Chemical formula

[0013] In this way, when the ether-based polymer in the embodiment of the present application satisfies the above range, it further reduces entanglement between molecular chains, facilitating dispersion of solvent molecules in the electrolyte between the molecular chains, which also contributes to the formation of a gel-like material. Furthermore, since the ether-based polymer still maintains a certain degree of entanglement between molecular chains, it effectively stores the electrolyte on the surface of the active material and improves its wettability to the active material. The gel-like material can release the solvent molecules and return to a polymeric state at high temperatures, resulting in a certain degree of elasticity. The interface between the ether-based polymer and the active material particles becomes deformable, allowing it to deform during the charge-discharge cycle of the battery. This reduces the risk of peeling of the internal structure of the electrode sheet, improves the structural stability of the electrode sheet as a whole, and improves the cycle performance of the battery cell.

[0014] In some embodiments, the adsorbent polymer comprises an ester-based polymer, and for sheet-like structures made from the ester-based polymer, (T m3The elastic modulus G’-loss elastic modulus G’’ curve is obtained by a dynamic frequency scanning test at (+20)°C, and the slope K2 of the elastic modulus G’-loss elastic modulus G’’ curve is 1 < K2 < ∞, and T m3 (°C) represents the melting temperature of the ester-based polymer, and optionally, 1 < K2 ≤ 100, and more optionally, 1 < K2 ≤ 10, Optionally, the glass transition temperature T of the ester-based polymer g3 (°C) is -100 ≤ T g3 ≤ 50, and optionally, -80 ≤ T g3 ≤ 30, More optionally, the ester-based polymer contains at least one of the compounds represented by formula (CI) to the compounds represented by formula (CIII),

Chemical formula

Chemical formula

Chemical formula

[0015] In this way, when the ester-based polymer in the embodiment of the present application satisfies the above range, it further reduces the entanglement of molecular chains, facilitating the dispersion of solvent molecules in the electrolyte between the molecular chains, which also contributes to the formation of a gel-like substance. Furthermore, since the ester-based polymer still maintains a certain degree of entanglement of molecular chains, it effectively stores the electrolyte on the surface of the active material and improves its wettability to the active material. The gel-like substance can release the solvent molecules and return to a polymeric state at high temperatures, resulting in a certain degree of elasticity. The interface between the ester-based polymer and the active material particles becomes deformable, allowing it to deform during the charge-discharge cycle of the battery. This reduces the risk of peeling of the internal structure of the electrode sheet, improves the structural stability of the electrode sheet as a whole, and improves the cycle performance of the battery cell.

[0016] In some embodiments, the adsorbent polymer comprises an aldehyde ketone polymer, and is more effective than a sheet-like structure made from an ester-based polymer (T m4 The elastic modulus G'-loss modulus G'' curve was obtained by dynamic frequency scanning test at +20°C, and the slope K3 of the elastic modulus G'-loss modulus G'' curve was 0.8≦K3<∞, and T m4 (° C.) represents the melting temperature of the aldehyde ketone polymer, optionally 0.8≦K3≦100, and more optionally 0.8≦K3≦10.

[0017] Optionally, the glass transition temperature T of the aldehyde ketone polymer g4 (℃) is -100≦T g4 ≦50, and optionally, −80≦T g4 ≦30.

[0018] Further optionally, the aldehyde ketone polymer comprises at least one of a compound represented by formula (DI) and a compound represented by formula (DII), [ka] In formula (DI), R 41 contains a single bond or a substituted or unsubstituted C1-C6 methylene group, and R 42 contains a hydrogen atom or a substituted or unsubstituted C1-C6 alkyl group, [ka] In formula (DII), R 43 ~R 46 each independently represent 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 any positive integer of 0 to 5, and at least one of r and s is selected from any positive integer; The degree of polymerization n of the aldehyde ketone polymer is selected from any positive integer of 500 to 15,000.

[0019] In this way, when the aldehyde ketone polymer according to the embodiment of the present application satisfies the above range, it further reduces entanglement between molecular chains, facilitating dispersion of solvent molecules in the electrolyte between the molecular chains, which also contributes to the formation of a gel-like substance. Furthermore, since the aldehyde ketone polymer still maintains a certain degree of entanglement between molecular chains, it effectively stores the electrolyte on the surface of the active material and improves its wettability. The gel-like substance can release the solvent molecules and return to a polymeric state at high temperatures, resulting in a certain degree of elasticity. The interface between the aldehyde ketone polymer and the active material particles becomes deformable, which allows it to deform during the charge / discharge cycle of the battery, reducing the risk of peeling of the internal structure of the electrode sheet, improving the structural stability of the electrode sheet as a whole, and improving the cycle performance of the battery cell.

[0020] In some embodiments, the molecular weight of the adsorbent polymer is 2.0×10 5 g / mol ~ 1.2 × 10 6 g / mol.

[0021] A second aspect of the present application provides a battery comprising an electrode sheet according to any of the embodiments of the first aspect of the present application.

[0022] In some embodiments, the electrode sheet is a positive electrode sheet.

[0023] In some embodiments, the electrode sheet is a negative electrode sheet.

[0024] A third aspect of the present application provides a power consuming device including a battery according to the second aspect of the present application. [Brief explanation of the drawings]

[0025] In order to more clearly explain the technical solutions of the embodiments of the present application, the drawings necessary for the embodiments of the present application will be briefly described below. It is obvious that the drawings described below are only some embodiments of the present application, and a person skilled in the art can derive other drawings based on the drawings without any creative work.

[0026] [Figure 1] FIG. 1 is a schematic diagram of one embodiment of a battery cell of the present application. [Figure 2] FIG. 2 is an exploded schematic view of an embodiment of the battery cell of FIG. 1. [Figure 3] 1 is a schematic diagram of one embodiment of a battery module of the present application. [Figure 4] 1 is a schematic diagram of one embodiment of a battery pack of the present application. [Figure 5] 5 is an exploded schematic view of the embodiment of the battery pack shown in FIG. 4. [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.

[0027] The drawings are not necessarily drawn to scale. [Explanation of symbols]

[0028] 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 device. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, the electrode sheet, battery, and power consumption device of the present application will be described in detail using specifically disclosed embodiments with appropriate reference to the drawings. However, unnecessary detailed description may be omitted. For example, detailed description of already well-known matters or redundant description of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. Note that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure and are not intended to limit the subject matter described in the claims.

[0030] The "ranges" disclosed herein are defined by a lower limit and an upper limit. A given range is defined by selecting one lower limit and one upper limit, and the selected lower and upper limits define the boundaries of the particular range. Such ranges may or may not include the end values, and may be arbitrarily combined; that is, any lower limit and any upper limit may be combined to form a range. For example, if a range of 60 to 120 or 80 to 110 is recited for a particular parameter, then ranges of 60 to 110 and 80 to 120 are also contemplated. Furthermore, if a range of 1 or 2 is recited as a minimum range value and a range of 3, 4, or 5 is recited as a maximum range value, then ranges including 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 to b" refers to a thumbnail of any combination of real numbers within the range a to b, where a and b are both real numbers. For example, a numerical range of "0 to 5" indicates that all real numbers within the range "0 to 5" are listed in this specification, and "0 to 5" is merely a thumbnail of the combinations of these numbers. Furthermore, when a parameter is expressed as an integer of 2 or greater, this is equivalent to disclosing that the parameter is an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0031] Unless otherwise specified, all of the embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0032] Unless otherwise specified, all of the embodiments and optional technical features of the present application can be combined with each other to form new technical solutions.

[0033] Unless otherwise specified, all steps in this application may be performed in order or randomly, but are preferably performed in order. For example, if a method includes steps (a) and (b), the method may include performing steps (a) and (b) in order, or may include performing steps (b) and (a) in order. For example, the method may further include step (c), and step (c) may be added to the method in any order; for example, 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).

[0034] In the embodiments of the present application, the terms "plurality" and "plurality" mean two or more or two or more kinds.

[0035] The term "alkyl group" includes straight-chain alkyl and branched-chain alkyl. 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, the alkyl group may include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and the like. The alkyl group may also be optionally substituted. When substituted, the substituent may include a fluorine atom.

[0036] The term "alkoxy group" refers to a group in which an alkyl group and an oxygen atom are linked 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 includes a methoxy group, an ethoxy group, and a propoxy group. In addition, the alkoxy group may be optionally substituted.

[0037] The term "halogen atom" means a fluorine atom, a chlorine atom, a bromine atom, and the like.

[0038] The term "hydrogen" refers to 1H (protium, H), 2H (deuterium, D), or 3H (tritium, T). In each embodiment, "hydrogen" may be 1H (protium, H).

[0039] The battery comprises an electrode assembly and an electrolyte. The electrode assembly comprises a positive electrode sheet including a positive electrode film layer containing a positive electrode active material capable of providing active ions, a negative electrode sheet including a negative electrode film layer containing a negative electrode active material, and a separator disposed between the positive electrode sheet and the negative electrode sheet. The separator mainly functions to prevent short-circuiting between the positive electrode sheet and the negative electrode sheet, while allowing the active ions to pass freely through to form a circuit.

[0040] In many cases, the active material layer has low affinity for the electrolyte solution and poor infiltration of the electrolyte solution into the active material layer, resulting in poor liquid storage capacity of the active material layer. When a battery is subjected to external pressure during use, transportation, or module assembly, the electrolyte solution in the active material layer is pushed out of the active material layer, gradually making it difficult to reabsorb the electrolyte solution, which may result in a decrease in battery capacity or deterioration of the battery's cycle characteristics.

[0041] In related art, it has been considered to introduce an in-situ polymerizable polymer into an electrode sheet to lock the electrolyte, but when this polymer polymerizes in-situ to form an in-situ gel, most of the electrolyte is locked inside the polymer, losing its fluidity. As a result, a solid-solid interface is formed between the polymer and the active material particles, resulting in poor deformability of the electrode sheet. During the charge-discharge cycle of the battery, the electrode sheet's strain adaptability is reduced, and peeling is likely to occur at the solid-solid interface, breaking the electrolyte bridge and deteriorating the battery's cycle performance, making it impossible to solve the above problem.

[0042] In view of the above problems, an embodiment of the present application provides an electrode sheet, the film layer of which contains an active material and an adsorbent polymer, and the adsorbent polymer physically adsorbs the electrolyte onto the surface of the active material particles to achieve a liquid locking effect, improving the infiltration of the electrolyte into the electrode sheet, and also enabling the electrode sheet to flexibly release the electrolyte when the temperature of the battery system rises or in a dry or other liquid-starved environment, thereby improving the deformability of the interface between the adsorbent polymer and the active material and buffering the deformation of the interface between the adsorbent polymer and the active material during the charge-discharge cycle of the battery, improving the structural stability of the electrode sheet, and improving the cycle performance of the battery.

[0043] The technical solution of this application will be described in detail below. Electrode sheet

[0044] According to a first aspect, an embodiment of the present application provides a battery comprising a current collector and a film layer provided on at least one side of the current collector, the film layer including an active material and an adsorptive polymer; At 45°C, an adsorbent polymer is added to a predetermined electrolyte solution to form a polymer system, the mass ratio of the predetermined electrolyte solution to the adsorbent polymer is 1:15, the predetermined electrolyte solution includes dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), and lithium hexafluorophosphate (LiPF), the dimethyl carbonate, ethyl methyl carbonate, and ethylene carbonate are the same mass, and the concentration of lithium hexafluorophosphate (LiPF) is 1 mol / L; The polymer system is allowed to stand at 45°C for 60 hours, and then allowed to stand at 25°C for 24 hours or more, and then filtered through a 200-mesh filter. The remaining filtrate is the first substance, and the mass n of the adsorbent polymer is g, and the mass m1 of the first substance is g, and the adsorbent polymer and the first substance satisfy 3≦m1 / n≦35; After drying the first material at 60°C for 24 hours or more, a second material is obtained, and the mass m2 of the second material is expressed in g, and the second material and the first material satisfy 1.00≦m2 / n≦1.05, thereby providing an electrode sheet.

[0045] The predetermined electrolyte has a similar or nearly identical composition to the electrolyte in the battery, and when mixed with the adsorbent polymer, can simulate the conditions that the adsorbent polymer will experience in the battery system. Dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and ethylene carbonate (EC) are considered solvents for the predetermined electrolyte, and lithium hexafluorophosphate (LiPF6) is the lithium salt for the predetermined electrolyte.

[0046] The polymer system undergoes a two-stage settling treatment, consisting of standing at 45°C for 60 hours and then standing at 25°C for at least 24 hours, after which at least a portion of the polymer system is converted into a gel-like substance. The polymer system after the two-stage settling treatment is then filtered through a 200-mesh filter, and the remaining filtrate is designated as the first substance, from which the predetermined electrolyte not involved in the formation of the gel-like substance can be removed by filtration. In an embodiment of the present application, m1 / n can be defined as the precipitation value and can represent the ability of the adsorbent polymer and the predetermined electrolyte to be converted into a gel-like substance. The first substance includes a gel-like substance consisting mainly of the adsorbent polymer and the predetermined electrolyte, and in such a gel-like substance, the structural units of the adsorbent polymer remain largely unchanged. A ratio m1 / n of 3≦m1 / n≦15 indicates that the adsorbent polymer has a strong ability to form a gel-like substance. At high temperatures, such as 45°C, the adsorbent polymer allows its molecular chains to expand, promoting attraction and physical bonding between the adsorbent polymer molecular chains and the electrolyte solvent, contributing to the bonding of the adsorbent polymer molecular chains and the solvent, and allowing the electrolyte to be stored in the film layer. Meanwhile, at low, safe operating temperatures, such as 25°C, the adsorbent polymer may not be mobile. Therefore, it adheres to the surface of the active material particles, locking the electrolyte in the spatial environment where the adsorbent polymer is present. This improves the liquid storage capacity of the film layer and improves the electrolyte's infiltration into the film layer, contributing to the normal transport of lithium ions. Furthermore, the adsorbent polymer provides good protection for the active material and reduces interfacial side reactions, thereby improving the cycle performance of secondary batteries using the adsorbent polymer.

[0047] After drying the first material at 60°C for 24 hours or more, a second material is obtained. The drying process is a process in which the predetermined electrolyte in the first material is washed away, and the predetermined electrolyte in the first material gradually volatilizes. The remaining second material mainly contains an adsorbent polymer, and this adsorbent polymer has approximately the same structure and composition as the adsorbent polymer originally added to the predetermined electrolyte. In an embodiment of the present application, m2 / n can be defined as the desorption capacity, which represents the ability of the first material to desorb from the predetermined electrolyte. A ratio of 1.00≦m2 / n≦1.05 indicates that the content of the second material and the adsorbent polymer is not significantly different, and the first material has a strong ability to desorb from the predetermined electrolyte. After the adsorbent polymer is formed into a gel-like material, it releases the predetermined electrolyte locked in the gel-like material under high temperature or dry conditions, allowing for flexible storage of the predetermined electrolyte. The remaining adsorbent polymer after the predetermined electrolyte is released can improve the deformability of the interface between the adsorbent polymer and the active material, buffering deformation of the interface between the adsorbent polymer and the active material during the charge-discharge cycle of the battery, improving the structural stability of the electrode sheet, and improving the cycle performance of the battery.

[0048] In an embodiment of the present application, the process of the adsorbent polymer physically adsorbing the electrolyte is reversible. When the system temperature is somewhat high, for example, at the high normal operating temperature of the battery system (first temperature), the adsorbent polymer can promote attraction and physical bonding between the adsorbent polymer molecular chains and the solvent while allowing the molecular chains to expand, thereby forming an in-situ gel-like substance. When the system temperature is lowered to the low normal operating temperature of the battery system (second temperature), the in-situ gel-like substance adheres to the surface of the active material particles, locking the electrolyte in the space or environment where the adsorbent polymer is present, protecting the active material interface and contributing to the normal transport of lithium ions. Furthermore, when the system temperature is higher, for example, at the higher normal operating temperature of the battery system (third temperature) or in a dry or other liquid-starved environment, the locked electrolyte is released, allowing for flexible electrolyte storage. When the active particles expand and deform during charge and discharge, the gelled absorbent polymer releases the liquid electrolyte in a timely manner to buffer the deformation of the interface between the polymer and the active particles, thereby improving the battery's cycle performance. In an embodiment of the present application, the second temperature is less than the first temperature, and the first temperature is less than the third temperature.

[0049] In an embodiment of the present application, 3≦m1 / n≦35, and optionally 5≦m1 / n≦35. For example, m1 / n may be 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, or a range consisting of any two of the above values.

[0050] In some embodiments, the adsorbent polymer may include at least one of a fluoropolymer, an ether-based polymer, an ester-based polymer, and an aldehyde-ketone polymer. The adsorbent polymer can reversibly adsorb and release the electrolyte, allowing the electrolyte to effectively infiltrate the active material, improving the structural stability of the electrode sheet and the cycling performance of the battery cell.

[0051] Next, specific types of adsorptive polymers will be described. [Fluoropolymer]

[0052] In some embodiments, the adsorbent polymer may comprise a fluoropolymer.

[0053] In some embodiments, the crystallinity X of the fluoropolymer by differential scanning calorimetry c1 (%) is 0 <X c1 For example, the crystallinity X of the fluoropolymer measured by differential scanning calorimetry is ≦30. c1 The percentage may be 1%, 5%, 10%, 15%, 20%, 25%, 30%, or a range consisting of any two of the above values.

[0054] In some embodiments, the melting temperature T of the fluoropolymer m1 (℃) is 0 <T m1 ≦140. For example, the melting temperature of the polymer 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.

[0055] In some embodiments, the glass transition temperature T g1 (℃) is -150≦T g1≦60. For example, the glass transition temperature of the fluoropolymer may be −150° C., −140° C., −135° C., −130° C., −125° C., −120° C., −110° C., −100° C., −90° C., −80° C., −70° C., −65° C., −60° C., −50° C., −45° C., −40° C., −35° C., −30° C., −25° C., −20° C., −15° C., −10° C., −5° C., 0° C., 5° C., 10° C., 15° C., 20° C., 25° C., 30° C., 40° C., 45° C., 50° C., 55° C., 60° C., or a range consisting of any two of the foregoing values.

[0056] Crystallization refers to the process by which atoms, ions, or molecules in a material are arranged in a certain spatial order to form order. The conformation of an adsorbent polymer in a crystal is determined by both intramolecular and intermolecular factors, and intermolecular forces affect the packing density between molecular chains. Crystallinity X C1 is used to represent the degree of crystallization of a material and can be measured by differential scanning calorimetry (DSC). Specifically, the measurement step involves placing 0.5 g to 0.8 g of a sample in a crucible and heating the sample at a rate of 10 °C / min under a nitrogen gas atmosphere until the material-specific T g1 From an initial temperature 20°C lower than the material-specific T m1 The actual glass transition temperature T of the material is determined based on the heat absorption / dissipation peak value or transition point of the material during the temperature increase / decrease treatment. g1 and melting temperature T m1 and determining the following:

[0057] In this way, the fluoropolymer has a low crystallinity, melting temperature, or glass transition temperature, and the flexibility of the fluoropolymer molecular chains is good, which makes the molecular chain segments more flexible and adjacent molecular chains more easily cleaved, allowing the solvent molecules in the electrolyte to enter between the fluoropolymer molecular chains and form a gel-like substance, thereby effectively storing the electrolyte on the surface of the active material and improving its wettability into the active material. The gel-like substance can release the solvent molecules and return to a polymer state at high temperatures, so it has a certain degree of elasticity, and the interface between the fluoropolymer and the active material particles can deform, allowing it to deform during the charge-discharge cycle of the battery, reducing the risk of peeling off the internal structure of the electrode sheet, improving the structural stability of the entire electrode sheet, and improving the cycle performance of the battery cell.

[0058] In some embodiments, the fluoropolymer comprises at least one of a compound represented by formula (AI) through (AIII).

[0059] The compound represented by formula (AI) is as follows: [ka]

[0060] In formula (AI), R 11 , R 12 , R 13 and R 14 each independently contains a hydrogen atom, a fluorine atom, a chlorine atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted alkoxy group; R 11 , R 12 , R 13 and R 14 At least one of them contains a fluorine atom.

[0061] Selectively, R 11 , R 12 , R 13 and R 14each independently contains a hydrogen atom, a fluorine atom, a chlorine atom, a substituted or unsubstituted C1 to C10 alkyl group, or a substituted or unsubstituted C1 to C10 alkoxy group.

[0062] Selectively, R 11 , R 12 , R 13 and R 14 each independently includes a hydrogen atom, a fluorine atom, a chlorine atom, a substituted or unsubstituted C1 to C3 alkyl group, or a substituted or unsubstituted C1 to C3 alkoxy group.

[0063] More selectively, R 11 , R 12 , R 13 and R 14 each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, a fluoromethyl group, a methoxy group, or a perfluoromethoxy group.

[0064] In some embodiments, the degree of polymerization of the fluoropolymer, n, is selected from any positive integer between 1000 and 30000, such as 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 11000, 12000, 13000, 14000, 15000, 16000, 17000, 18000, 19000, 20000, 21000, 22000, 23000, 24000, 25000, 26000, 27000, 28000, 29000, or a range consisting of any two of the foregoing numbers.

[0065] Optionally, 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, which may include a fluorine atom, a bromine atom, etc., and is optionally a fluorine atom.

[0066] In some embodiments, the fluoropolymer comprises at least one of compounds represented by formula (AI-1) through formula (AI-11). [ka]

[0067] The compound represented by formula (AII) is as follows: [ka]

[0068] In formula (AII), R 11 , R 12 , R 13 and R 14 each independently contains a hydrogen atom, a fluorine atom, a chlorine atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted alkoxy group, and R 11 , R 12 , R 13 and R 14 At least one of them contains a fluorine atom.

[0069] Selectively, R 11 , R 12 , R 13 and R 14 each independently contains a hydrogen atom, a fluorine atom, a chlorine atom, a substituted or unsubstituted C1 to C10 alkyl group, or a substituted or unsubstituted C1 to C10 alkoxy group.

[0070] Selectively, R 11 , R 12 , R 13 and R 14 each independently includes a hydrogen atom, a fluorine atom, a chlorine atom, a substituted or unsubstituted C1 to C3 alkyl group, or a substituted or unsubstituted C1 to C3 alkoxy group.

[0071] More selectively, R 11 , R 12 , R 13 and R 14each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, a fluoromethyl group, a methoxy group, or a perfluoromethoxy group.

[0072] In some embodiments, the degree of polymerization n of the fluoropolymer is selected from any positive integer between 1000 and 30000, such as 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 11000, 12000, 13000, 14000, 15000, 16000, 17000, 18000, 19000, 20000, 21000, 22000, 23000, 24000, 25000, 26000, 27000, 28000, 29000, or a range consisting of any two of the foregoing numbers.

[0073] Optionally, 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, which may include a fluorine atom, a bromine atom, etc., and is optionally a fluorine atom.

[0074] In some embodiments, the fluoropolymer comprises at least one of compounds represented by formula (AII-1) through formula (AII-5). [ka]

[0075] The compound represented by formula (AIII) is as follows: [ka]

[0076] In formula (AIII), R 15 includes a single bond, a substituted or unsubstituted alkyl group, and if substituted, the substituent includes a fluorine atom.

[0077] 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.

[0078] Selectively, R 15 includes a single bond, or a substituted or unsubstituted C1 to C3 alkyl group.

[0079] In some embodiments, p is selected from any positive integer from 1 to 3, for example, 1, 2, or 3.

[0080] In some embodiments, the degree of polymerization n of the fluoropolymer is selected from any positive integer in the range of 1000 to 30000, such as 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 11000, 12000, 13000, 14000, 15000, 16000, 17000, 18000, 19000, 20000, 21000, 22000, 23000, 24000, 25000, 26000, 27000, 28000, 29000, or a range consisting of any two of the foregoing numbers.

[0081] In some embodiments, the fluoropolymer comprises at least one of compounds represented by formula (AIII-1) through formula (AIII-3). [ka]

[0082] For example, the fluoropolymer may include one or more of polyperfluoroethylene (PTFE), polyvinylidene fluoride (PVDF), perfluoroethylenepropene copolymer (FEP), perfluoroalkoxy polymer (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).

[0083] Optionally, the fluoropolymer comprises one or more of polyperfluoroethylene (PTFE), polyvinylidene fluoride (PVDF), perfluoroethylene propene copolymer (FEP), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyvinylidene fluoride-trifluoroethylene copolymer (PVDF-TrFE).

[0084] The fluoropolymer may be derived from one or more monomers such as fluorocycloethane, 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 fluorocycloethane, fluoroethylene, 1,2-difluoroethylene, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene, 3,3,3-trifluoropropylene, trifluoropropylene, tetrafluoropropylene, and pentafluoropropylene.

[0085] In embodiments of the present application, the polymer may be obtained by copolymerizing the above structural group with a small amount of other structural group (e.g., olefin compounds, ester monomers, nitrile monomers such as acrylonitrile, amide monomers such as acrylamide, acrylic acid compounds, etc.). Because the liquid affinity of such small amounts of monomers is poor, the above-mentioned fluoropolymer monomers can be copolymerized with such monomers to increase the swelling ratio and compressive modulus of the adsorbent polymer.

[0086] In some embodiments, the molecular weight of the adsorbent polymer is 2×10 5 g / mol ~ 1.2 × 10 6 g / mol.

[0087] For example, the molecular weight of the adsorbent polymer is 2×10 5 g / mol, 5 × 10 5 g / mol, 8 × 10 5 g / mol, 1×10 6 g / mol, 1.2 × 10 6 g / mol, or a range consisting of any two of the above values. [Ether polymer]

[0088] In some embodiments, the adsorbent polymer comprises an ether-based polymer.

[0089] In some embodiments, for a sheet-like structure made from an ether-based polymer, (T m2 The elastic modulus G'-loss modulus G'' curve was obtained by dynamic frequency scanning test at +20°C, and the slope K1 of the elastic modulus G'-loss modulus G'' curve was 1 <K1<∞であり、T m2 (°C) represents the melting temperature of the ether polymer.

[0090] 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, and the dried ether-based polymer is thermocompressed in a flat vulcanizer to form a sheet. m2The temperature is +20°C, the rolling thickness is 1 to 2 mm, the rolling time is 2 minutes, and the pressure is 8 MPa. After rolling for 2 minutes, the sample is removed and placed in another vulcanizer of the same model and cold pressed at a pressure of 10 MPa. A circular die with a diameter of 25 mm is used to obtain a polymer wafer (sheet-like structure) of a certain size. For example, the sheet-like structure may be a wafer with a thickness of 1 to 2 mm and a diameter of 25 mm, and may be manufactured according to the specifications required for the test device.

[0091] According to the classical linear viscoelastic conclusions, for polymers, especially linear polymers, the elastic modulus G'-loss modulus G'' curve in the terminal region (the range close to the maximum angular velocity) conforms to the frequency dependence, and the longest chain of the polymer influences the viscoelastic behavior.

[0092] The dynamic frequency sweep test is specifically performed using a TA-AR 2000EX rotational rheometer (TA Instruments, USA) on parallel plates with a diameter of 25 mm and a thickness of 0.9 mm. To ensure that the test is performed in the linear viscoelastic region, the strain during the dynamic frequency sweep test is 2% and the test temperature is (T m2 +20) °C, and the test frequency scan range is 500 rad / s ≤ w 2 ≦0.05 rad / s, thereby enabling data to be acquired in the lowest possible frequency range.

[0093] The dynamic frequency scanning test can characterize the degree of entanglement between molecular chains during solid-phase melting (molten state). Long branched structures, network structures, and low cross-linked structures have a higher degree of entanglement compared to linear structures or short branched structures and may deviate from linear ends, so the ether-based polymer exhibits solidification behavior. When the ether-based polymer of the present application meets the above range, it can further reduce the entanglement between molecular chains, facilitate the dispersion of solvent molecules in the electrolyte into the molecular chains, and contribute to the formation of a gel-like substance. Also, the ether-based polymer can still maintain a certain degree of entanglement state between molecular chains, effectively store the electrolyte, and improve the wettability to the active material. The gel-like substance can release solvent molecules and return to the polymer state at high temperatures, so it has a certain degree of elasticity. The interface between the ether-based polymer and the active material particles can be deformed, so it can be deformed during the charge and discharge cycles of the battery, reducing the risk of peeling of the internal structure of the electrode sheet, improving the structural stability of the entire electrode sheet, and improving the cycle performance of the battery cell.

[0094] In some embodiments, 1 < K1 ≤ 100, and optionally, 1 < K1 ≤ 10. For example, K1 may be 1.01, 1.1, 2, 5, 10, 15, 20, 30, 50, 100, 200, 500, 1,000, 5,000, 10,000, or a range consisting of any two of the above numerical values.

[0095] In some embodiments, the glass transition temperature T of the ether-based polymer g2 (°C) is -100 ≤ T g2 ≤ 50, and optionally, -80 ≤ T g2≦30. For example, the glass transition temperature of the ether-based polymer may be −100°C, −90°C, −80°C, −70°C, −65°C, −60°C, −50°C, −45°C, −40°C, −35°C, −30°C, −25°C, −20°C, −15°C, −10°C, −5°C, 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 40°C, 45°C, 50°C, or a range consisting of any two of the above values. Ether-based polymers have a certain degree of flexibility at temperatures above their glass transition temperature, which facilitates the formation of a gel-like substance, improves the infiltration effect into the electrode sheet, and can improve the cycle performance of the battery.

[0096] In some embodiments, the ether-based polymer comprises a compound represented by formula (BI). [ka]

[0097] In formula (BI), R 21 and R 22 each independently contains a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted alkoxy group; R 23 includes a single bond and a substituted or unsubstituted methylene group.

[0098] Selectively, R 21 and R 22 each independently includes a hydrogen atom, a substituted or unsubstituted C1 to C10 alkyl group, or a substituted or unsubstituted C1 to C10 alkoxy group.

[0099] Selectively, R 21 and R 22 each independently includes a hydrogen atom, a substituted or unsubstituted C1 to C3 alkyl group, or a substituted or unsubstituted C1 to C3 alkoxy group.

[0100] Selectively, R 23 includes a single bond, a substituted or unsubstituted C1 to C10 methylene group.

[0101] Selectively, R23 includes a single bond, or a substituted or unsubstituted C1 to C5 methylene group.

[0102] For example, the ether-based polymer contains at least one of the compounds represented by formula (BI-1) to formula (BI-8). [ka]

[0103] In some embodiments, the ether-based polymer comprises a compound represented by formula (BII). [ka]

[0104] In formula (BII), R 24 ~R 27 each independently contains a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, or an ether group; R 24 ~R 27 At least one of the groups contains a substituted or unsubstituted alkoxy group or an ether group.

[0105] Selectively, R 24 ~R 27 each independently includes a hydrogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C10 alkoxy group, or an ether group.

[0106] Selectively, R 24 ~R 27 each independently includes a hydrogen atom, a substituted or unsubstituted C1 to C3 alkyl group, a substituted or unsubstituted C1 to C3 alkoxy group, or an ether group.

[0107] In some embodiments, the ether-based polymer comprises at least one of the compounds represented by formula (BII-1) to formula (BII-7). [ka]

[0108] The above polymers are merely some examples of structural groups in the main 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, olefin-based compounds, ester-based monomers, nitrile-based monomers such as acrylonitrile, amide-based monomers such as acrylamide, and compounds such as acrylic acid).

[0109] 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 halogen atom may include at least one of a fluorine atom and a bromine atom, and is preferably a fluorine atom.

[0110] In some embodiments, the degree of polymerization n of the ether-based polymer is selected from any positive integer of 1500 to 25000, and may be, for example, 1500, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 11000, 12000, 13000, 14000, 15000, 16000, 17000, 18000, 19000, 20000, 21000, 22000, 23000, 24000, 25000, or a range consisting of any two of the above numbers.

[0111] Alternatively, the degree of polymerization n of the ether-based polymer is selected from any positive integer within the range of 3,000 to 18,000.

[0112] In some embodiments, the molecular weight of the adsorbent polymer is 2×10 5 g / mol ~ 1.2 × 10 6 g / mol. For example, the molecular weight of a polymer is 2×10 5 g / mol, 5 × 10 5 g / mol, 8 × 10 5 g / mol, 1×10 6 g / mol, 1.2 × 106 It may also be in the range of g / mol or any two of the above numerical values. [Ester-based polymer]

[0113] In some embodiments, the adsorbent polymer includes an ester-based polymer.

[0114] In some embodiments, for the sheet-like structure produced from the ester-based polymer, an elastic modulus G'-loss elastic modulus G'' curve is obtained by a dynamic frequency scanning test at (T m3 +20) °C, and the slope K2 of the elastic modulus G'-loss elastic modulus G'' curve is 1 < K2 < ∞, where T m3 (°C) represents the melting temperature of the ester-based polymer.

[0115] Specifically, since the manufacturing process of the sheet-like structure is the same as that of the ether-based polymer, it will not be described in this specification. When the ester-based polymer of this application satisfies the above range, the entanglement between molecular chains is further reduced, making it easier for solvent molecules in the electrolyte to disperse between molecular chains, and it can also contribute to the formation of a gel-like substance. Also, the ester-based polymer still maintains a certain degree of entanglement state between molecular chains, effectively storing the electrolyte and improving the wettability to the active material. The gel-like substance can release solvent molecules and return to the polymer state at high temperatures, so it has a certain degree of elasticity. The interface between the ester-based polymer and the active material particles can be deformed, thereby being able to deform during the charge and discharge cycles of the battery, reducing the risk of peeling of the internal structure of the electrode sheet, improving the structural stability of the entire electrode sheet, and improving the cycle performance of the battery cell.

[0116] In some embodiments, 1 < K2 ≤ 100, and optionally, 1 < K2 ≤ 10. For example, K2 may be in the range of 1.01, 1.1, 2, 5, 10, 15, 20, 30, 50, 100, 200, 500, 1000, 5000, 10000, or any two of the above numerical values.

[0117] In some embodiments, the glass transition temperature, T g3 (℃) is -100≦T g3 ≦50, and optionally, −80≦T g3 ≦30. For example, the glass transition temperature of the ester-based polymer may be −100°C, −90°C, −80°C, −70°C, −65°C, −60°C, −50°C, −45°C, −40°C, −35°C, −30°C, −25°C, −20°C, −15°C, −10°C, −5°C, 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 40°C, 45°C, 50°C, or a range consisting of any two of the above values. Because the ester-based polymer has a certain degree of flexibility at temperatures equal to or higher than its glass transition temperature, it can easily form a gel-like substance, improve the infiltration effect into the electrode sheet, and improve the cycle performance of the battery.

[0118] In some embodiments, the ester-based polymer comprises a compound represented by formula (CI). [ka]

[0119] In formula (CI), R 31 , R 32 and R 33 each independently contains a hydrogen atom or a substituted or unsubstituted alkyl group, and R 34 includes a substituted or unsubstituted alkyl group or a substituted or unsubstituted hydroxyalkyl group.

[0120] Selectively, R 31 , R 32 and R 33 each independently contains a hydrogen atom or a substituted or unsubstituted C1 to C10 alkyl group.

[0121] Selectively, R 31 , R 32 and R 33 each independently contains a hydrogen atom or a substituted or unsubstituted C1 to C8 alkyl group.

[0122] In some embodiments, R 34 includes a substituted or unsubstituted C1 to C10 alkyl group, or a substituted or unsubstituted C1 to C10 hydroxyalkyl group.

[0123] In some embodiments, R 34 includes a substituted or unsubstituted C1 to C8 alkyl group, or a substituted or unsubstituted C1 to C8 hydroxyalkyl group.

[0124] In some embodiments, R 31 includes a hydrogen atom or a substituted or unsubstituted methyl group.

[0125] In some embodiments, R 32 and R 33 each independently contains a hydrogen atom.

[0126] For example, the ester-based polymer contains at least one of the compounds represented by formula (CI-1) to formula (CI-15). [ka] [ka]

[0127] In some embodiments, the ester-based polymer comprises a compound represented by formula (CII). [ka]

[0128] In formula (CII), R 35 includes a substituted or unsubstituted methylene group.

[0129] Selectively, R 35 includes a substituted or unsubstituted C1 to C10 methylene group.

[0130] Selectively, R 35includes a substituted or unsubstituted C2 to C6 methylene group.

[0131] Selectively, R 35 includes a substituted or unsubstituted C2 to C4 methylene group.

[0132] For example, the ester-based polymer contains at least one of the compounds represented by formula (CII-1) to formula (CII-5). [ka]

[0133] In some embodiments, the ester-based polymer comprises a compound represented by formula (CIII). [ka]

[0134] In formula (CIII), R 36 , R 37 and R 38 each independently contains a hydrogen atom or a substituted or unsubstituted C1 to C8 alkyl group, and R 39 includes substituted or unsubstituted C1 to C8 alkyl groups.

[0135] Selectively, R 36 , R 37 and R 38 each independently contains a hydrogen atom or a substituted or unsubstituted C1 to C4 alkyl group.

[0136] For example, the ester-based polymer contains at least one of the compounds represented by formula (CIII-1) to formula (CIII-5). [ka]

[0137] The above polymers are merely some examples of structural groups in the main chain, and in embodiments of the present application, the adsorbent polymer may be obtained by copolymerizing the above structural groups with small amounts of other types of structural groups (e.g., olefin-based compounds, ester-based monomers, nitrile-based monomers such as acrylonitrile, amide-based monomers such as acrylamide, acrylic acid, and other compounds).

[0138] 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.

[0139] In some embodiments, the degree of polymerization n of the ester-based polymer is selected from any positive integer from 800 to 20,000, and may be, for example, 800, 1,000, 1,500, 2,000, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000, 9,000, 10,000, 11,000, 12,000, 13,000, 14,000, 15,000, 16,000, 17,000, 18,000, 19,000, 20,000, or a range consisting of any two of the above numbers.

[0140] In some embodiments, the degree of polymerization n of the ester-based polymer is selected from any positive integer of 1,000 to 15,000.

[0141] In some embodiments, the molecular weight of the adsorbent polymer is 2×10 5 g / mol ~ 1.2 × 10 6 g / mol.

[0142] For example, the molecular weight of the adsorbent polymer is 2×10 5 g / mol, 5 × 10 5 g / mol, 8 × 10 5 g / mol, 1×10 6 g / mol, 1.2 × 10 6 g / mol, or a range consisting of any two of the above values. [Aldehyde Ketone Polymer]

[0143] In some embodiments, the adsorbent polymer comprises an aldehyde ketone polymer.

[0144] In some embodiments, for a sheet-like structure made from an aldehyde ketone polymer, (T m4 The elastic modulus G'-loss modulus G'' curve was obtained by dynamic frequency scanning test at +20°C, and the slope K3 of the elastic modulus G'-loss modulus G'' curve was 0.8≦K3<∞, and T m4 (°C) represents the melting temperature of the aldehyde ketone polymer.

[0145] Specifically, the manufacturing process for the sheet-like structure is similar to that for ether-based polymers, and therefore will not be described herein. When the aldehyde ketone polymer of the present application satisfies the above range, it further reduces entanglement between molecular chains, facilitating dispersion of solvent molecules in the electrolyte between the molecular chains, and contributing to the formation of a gel-like substance. Furthermore, the aldehyde ketone polymer still maintains a certain degree of entanglement between molecular chains, effectively storing the electrolyte and improving its wettability for the active material. The gel-like substance can release the solvent molecules and return to a polymeric state at high temperatures, thereby possessing a certain degree of elasticity. The interface between the aldehyde ketone polymer and the active material particles becomes deformable, allowing it to deform during the charge / discharge cycle of the battery. This reduces the risk of peeling of the internal structure of the electrode sheet, improves the structural stability of the electrode sheet as a whole, and improves the cycle performance of the battery cell.

[0146] In some embodiments, 0.8≦K3≦100, and optionally, 0.8≦K3≦10. For example, K3 can be 0.8, 0.85, 0.9, 1, 1.01, 1.1, 2, 5, 10, 15, 20, 30, 50, 100, 200, 500, 1000, 5000, 10000, or a range consisting of any two of the foregoing values.

[0147] In some embodiments, the glass transition temperature, T g4 (℃) is -100≦Tg4 ≦50, and optionally, −80≦T g4 ≦30. For example, the glass transition temperature of the aldehyde ketone polymer may be −100°C, −90°C, −80°C, −70°C, −65°C, −60°C, −50°C, −45°C, −40°C, −35°C, −30°C, −25°C, −20°C, −15°C, −10°C, −5°C, 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 40°C, 45°C, 50°C, or a range consisting of any two of the above values. Because the aldehyde ketone polymer has a certain degree of flexibility at temperatures above its glass transition temperature, it can easily form a gel-like substance, improve the infiltration effect into the electrode sheet, and enhance the cycle performance of the battery.

[0148] In some embodiments, the aldehyde ketone polymer comprises a compound represented by formula (DI). [ka]

[0149] In formula (DI), R 41 contains a single bond or a substituted or unsubstituted C1-C6 methylene group, and R 42 includes a hydrogen atom or a substituted or unsubstituted C1 to C6 alkyl group.

[0150] Selectively, R 41 includes a single bond, or a substituted or unsubstituted C1-C2 methylene group.

[0151] Selectively, R 42 includes a hydrogen atom or a substituted or unsubstituted C1 to C3 alkyl group.

[0152] In the embodiments of the present application, a single bond means that there is no group and the atoms on both sides of the group are connected by a single bond, for example, R 41 is a single bond, R 41 means that the carbon atoms on both sides of are connected by a single bond.

[0153] For example, the aldehyde ketone polymer contains at least one of the compounds represented by formula (DI-1) to formula (DI-6). [ka]

[0154] For example, the aldehyde ketone polymer includes a compound represented by formula (DII). [ka]

[0155] 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 any positive integer.

[0156] Selectively, R 43 ~R 46 each independently comprises a hydrogen atom, a hydroxyl group, a substituted or unsubstituted C1 to C3 alkyl group, a substituted or unsubstituted C1 to C2 hydroxyalkyl group, or a substituted or unsubstituted C1 to C2 alkoxy group.

[0157] In some embodiments, the aldehyde ketone polymer comprises at least one of compounds represented by formula (DII-1) to (DII-4). [ka]

[0158] The above polymers are merely some examples of main chain structural groups, and in the embodiments of the present application, polymers may be obtained by copolymerizing the above structural groups with other types of structural groups (e.g., olefin-based compounds, enol-based compounds, acrylonitrile-based compounds, etc.).

[0159] 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, which may include at least one of a fluorine atom, a bromine atom, and a chlorine atom.

[0160] In some embodiments, the degree of polymerization n of the aldehyde ketone polymer may be selected from any positive integer between 500 and 15,000, such as 500, 800, 1,000, 1,500, 2,000, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000, 9,000, 10,000, 11,000, 12,000, 13,000, 14,000, 15,000, or a range consisting of any two of the above numbers.

[0161] Optionally, the degree of polymerization n of the aldehyde ketone polymer is selected from any positive integer of 500 to 10,000.

[0162] In some embodiments, the molecular weight of the aldehyde ketone polymer is 1.2×10 5 g / mol ~ 1.2 × 10 6 g / mol.

[0163] For example, the molecular weight of an 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 g / mol, 1.2 × 10 6 g / mol, or a range consisting of any two of the above values.

[0164] The relevant parameters of the adsorptive polymers according to the embodiments of the present application can be detected in the following manner.

[0165] The groups of the adsorbent polymer according to the embodiment of the present application can be detected by infrared spectroscopy (IR). Specifically, the adsorbent polymer was tested using a Thermo Nicolet Nexus 670 attenuated total reflectance-Fourier transform infrared spectrophotometer (FTIR-ATR) in accordance with GB / T 6040-2002, where the measurement range is 600-4000 cm for the ATR method. -1 and the reproducibility is ±2cm -1 and the resolution is 4cm -1 It has a higher penetration depth of 0.2 to 0.6 μm.

[0166] The structure of the adsorbent polymer according to the present application can be examined by nuclear magnetic resonance (NMR), specifically, 1H NMR and 13C NMR are performed on a Varian Mercury Plus-400 nuclear magnetic resonance apparatus, the test temperature is 20°C, the internal standard is TMS, the solvent is CDCl3, and the proton resonance frequency is 400 MHz.

[0167] The type of polymerizable monomer contained in the adsorbent polymer according to the embodiment of the present application (particularly applicable to monomers that occupy a small proportion in the polymer) can be tested using a pyrolysis gas chromatograph mass spectrometer, and the measurement steps are specifically as follows: A sample cup containing a precisely weighed 0.5 mg sample is fixed to a feed rod and inserted into a pyrolyzer attached near the GC (gas chromatograph) feed port; then, when the temperature of the pyrolyzer reaches the set temperature, the feed button is pressed to rapidly cause the sample cup to free fall into the center of the pyrolyzer; the volatile components are instantly gasified in an inert N2 atmosphere, carried by a carrier gas into the gas chromatograph column for separation, and finally detected by a flame ionization detector (FID) or a mass spectrometer (MS), thereby obtaining a gas chromatogram or total ion chromatogram.

[0168] The molecular weight of the adsorbent polymer according to the present application is a known value in the art and can be measured using common equipment and methods in the art, and can be tested by gel permeation chromatography (GPC) in accordance with GB / T21863-2008. The test steps are specifically as follows: Add 20 ml of deionized water to an appropriate amount of sample (enough to ensure that the sample concentration has a light blocking rate of 8% to 12%), and simultaneously perform external ultrasonic treatment for 5 minutes (53 KHz / 120 W) to ensure complete dispersion of the sample. Then, measure the sample in accordance with GB / T19077-2016 / ISO13320:2009. [Positive electrode sheet]

[0169] In some embodiments, the electrode sheet comprises a positive electrode sheet including a positive electrode current collector and a positive electrode film layer disposed on at least one side of the positive electrode current collector and containing a positive electrode active material and an adsorbent polymer. In this case, the negative electrode sheet may comprise a negative electrode current collector and a negative electrode film layer disposed on at least one side of the negative electrode current collector and containing a negative electrode active material and an adsorbent polymer. Alternatively, the negative electrode sheet may comprise a negative electrode current collector and a negative electrode film layer disposed on at least one side of the negative electrode current collector and containing a negative electrode active material, i.e., the negative electrode film layer does not contain an adsorbent polymer.

[0170] In some other embodiments, the electrode assembly includes a negative electrode sheet including a negative electrode current collector and a negative electrode film layer disposed on at least one side of the negative electrode current collector and containing a negative electrode active material and an adsorbent polymer, and in this case, the positive electrode film layer may include a positive electrode active material, i.e., does not include a fluoropolymer.

[0171] Further research has revealed that when both the positive electrode film layer and the negative electrode film layer contain an adsorbent polymer, the adsorbent polymer can improve the interfacial performance and structural stability of the positive electrode sheet as well as the interfacial performance and structural stability of the negative electrode sheet, thereby effectively improving the cycle performance of the battery cell.

[0172] In some embodiments, the mass content of the adsorbent polymer is 5% or less, preferably 0.05% to 5%, and more preferably 0.05% to 2%, based on the total mass of the positive electrode film layer. When the mass content of the adsorbent polymer is in the above range, the adsorbent polymer can effectively improve the interface performance and structural stability of the positive electrode sheet.

[0173] For example, the mass content of the adsorbent polymer was 0.05%, 0.08%, 0.10%, 0.11%, 0.12%, 0.15%, 0.16%, 0.18%, 0.20%, 0.22%, 0.25%, 0.28%, 0.30%, 0.32%, 0.35%, 0.38%, 0.40%, 0.42%, 0.45%, 0.48%, 0.50%, 0.55%, 0.58%, 0.60%, 0.70%, 0.80%, 0.90%, 0.95%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 1.10%, 1.11%, 1.12%, 1.13%, 1.14%, 1.15%, 1.16%, 1.17%, 1.18%, 1.19%, 1.20%, 1.21%, 1.22%, 1.23%, 1.24%, 1.25%, 1.26%, 1.27%, 1.28%, 1.29%, 1.29%, 1.30%, 1.31%, 1.32%, 1.33%, 1.34%, 1.35%, 1.36%, 1.37%, 1.38%, 1.39 ... , 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5.0%, or a range consisting of any two of the above values.

[0174] In some embodiments, the coating weight of the adsorbent polymer is 0.05 mg / 1540.25 mm 2 ~5mg / 1540.25mm 2 For example, 0.05 mg / 1540.25 mm 2 , 0.1mg / 1540.25mm 2 , 0.2mg / 1540.25mm 2 , 0.5mg / 1540.25mm 2 , 0.6mg / 1540.25mm 2 , 0.7mg / 1540.25mm 2 , 0.8mg / 1540.25mm 2 , 0.9mg / 1540.25mm2 、1.0mg / 1540.25mm 2 、1.1mg / 1540.25mm 2 、1.2mg / 1540.25mm 2 、1.3mg / 1540.25mm 2 、1.4mg / 1540.25mm 2 、1.5mg / 1540.25mm 2 、1.6mg / 1540.25mm 2 、1.7mg / 1540.25mm 2 、1.8mg / 1540.25mm 2 、1.9mg / 1540.25mm 2 、2.0mg / 1540.25mm 2 、2.1mg / 1540.25mm 2 、2.2mg / 1540.25mm 2 、2.3mg / 1540.25mm 2 、2.4mg / 1540.25mm 2 、2.5mg / 1540.25mm 2 、2.6mg / 1540.25mm 2 、2.7mg / 1540.25mm 2 、2.8mg / 1540.25mm 2 、2.9mg / 1540.25mm 2 、3.0mg / 1540.25mm 2 、3.1mg / 1540.25mm 2 、3.2mg / 1540.25mm 2 、3.3mg / 1540.25mm 2 、3.4mg / 1540.25mm 2 、3.5mg / 1540.25mm 2 、3.6mg / 1540.25mm 2 、3.7mg / 1540.25mm 2 、3.8mg / 1540.25mm 2 、3.9mg / 1540.25mm 2 、4.0mg / 1540.25mm 2 、4.1mg / 1540.25mm 2 、4.2mg / 1540.25mm 2 、4.3mg / 1540.25mm 2, 4.4mg / 1540.25mm 2 , 4.5mg / 1540.25mm 2 , 4.6mg / 1540.25mm 2 , 4.7mg / 1540.25mm 2 , 4.8mg / 1540.25mm 2 , 4.9mg / 1540.25mm 2 , 5.0mg / 1540.25mm 2 or a range consisting of any two of the above values. The coating weight of the adsorbent polymer is the coating weight on one side of the positive electrode film layer of the positive electrode sheet.

[0175] In the embodiments of the present application, the polymer mass content has a meaning known in the art and can be detected using devices and methods known in the art, for example, thermogravimetric analysis (TGA) in accordance with JYT014-1996. Specifically, a mass-temperature curve (i.e., a TG curve) is plotted based on the mass loss of the electrode sheet during the heating process, and the corresponding mass loss is read according to the polymer decomposition temperature. This is then used as the total mass of the polymer in the electrode sheet, and the polymer mass content and coating weight are calculated. During the test, the polymer mass content can be measured by a heating process in a nitrogen gas atmosphere, which involves heating from room temperature to 500°C at a rate of 5°C / min, then heating from 500°C to 600°C at a rate of 10°C / min, and then heating to 600°C for 10 minutes before stopping.

[0176] The positive electrode film layer includes a positive electrode active material, which may be a positive electrode active material for battery cells known in the art. For example, the positive electrode active material may include a lithium-containing positive electrode active material, such as an olivine-type phosphate active material or at least one of a layered structure positive electrode active material.

[0177] 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 zwherein 0≦x≦1.3, 0≦y≦1.3, 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.

[0178] For example, the layered structure positive electrode active material is a ternary material, such as lithium / sodium nickelate, lithium / sodium cobaltate, lithium / sodium manganate, lithium-rich layered material, and rock salt phase layered material. The general formula of the layered structure positive electrode active material 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, 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 is lithium cobalt oxide (LCO), lithium nickel oxide (LNO), lithium manganese oxide (LMO), LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NML33), LiNi 0.5 Co 0.2 Mn0.3 O2(NCM523), LiNi 0.6 Co 0.2 Mn 0.2 O2(NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), and one or more of NCA.

[0179] In a battery cell, active ions such as Li are absorbed, released, and consumed during the charge and discharge process, and therefore, when the battery cell is discharged to different states, the molar content of Li also varies. In the example positive electrode active material given in the embodiments of the present application, the molar content of Li is the value in the initial state of the material, i.e., the state before loading. When the positive electrode active material is applied to a battery system, the molar content of Li may change after charge and discharge cycles.

[0180] In the examples of the positive electrode active materials given in the embodiments of the present application, the molar content of oxygen (O) is merely a theoretical value and may change as oxygen is released from the lattice, and therefore, in reality, the molar content of oxygen (O) varies.

[0181] In an embodiment of the present application, the modified compound can be prepared by doping modification or coating modification, in which a doping element such as a transition metal can be added to the compound, and in which a surface coating can be performed using a material such as carbon, i.e., a carbon coating layer can be formed on the outer surface of the particle.

[0182] In some embodiments, the mass content of the positive electrode active material is 80% to 99.9%, and optionally 90% to 99%, based on the total mass of the positive electrode film layer, which contributes to improving the energy density of the battery cell.

[0183] In some embodiments, the positive electrode current collector has two opposing surfaces in the thickness direction thereof, and the positive electrode film layer may be provided on either or both of the two opposing surfaces of the positive electrode current collector.

[0184] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. Examples of metal foils include aluminum foil and aluminum alloy foil. The composite current collector may include a polymeric material base layer and a metal material layer formed on at least one surface of the polymeric material base layer. For example, the metal material may include one or more combinations selected from aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. The polymeric material base layer may include one or more combinations selected from polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0185] In some embodiments, the positive electrode film layer optionally further comprises a positive electrode conductive agent. In the embodiments of the present application, the type of the positive electrode conductive agent is not particularly limited. For example, the positive electrode conductive agent may comprise one or a combination of materials selected from the group consisting of 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 content of the positive electrode conductive agent is 5% or less based on the total mass of the positive electrode film layer.

[0186] In some embodiments, the positive electrode film layer optionally further includes a positive electrode adhesive. In the embodiments of the present application, the type of positive electrode adhesive is not particularly limited. For example, the positive electrode adhesive may include one or more combinations selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylic ester-based resin. In some embodiments, the mass content of the positive electrode adhesive is 5% or less based on the total mass of the positive electrode film layer. In the embodiments of the present application, the crystallinity of the positive electrode adhesive is higher than that of the fluoropolymer.

[0187] The positive electrode film layer is typically formed by applying a positive electrode slurry to a positive electrode current collector, drying, and cold pressing. The positive electrode slurry is typically formed by dispersing a positive electrode active material, an adsorptive polymer, an optional conductive agent, an optional adhesive, and any other optional components in a solvent and stirring the mixture uniformly. The solvent may be, but is not limited to, N-methylpyrrolidone (NMP). Of course, the production of the positive electrode sheet is not limited to the above method, and the above-mentioned production method may also be used. [Negative electrode sheet]

[0188] In some embodiments, the electrode sheet comprises a negative electrode sheet including a negative electrode current collector and a negative electrode film layer provided on at least one side of the negative electrode current collector and containing a negative electrode active material and an adsorbent polymer.

[0189] In some embodiments, the mass content of the adsorbent polymer is 6% or less, optionally 5% or less, and optionally 0.05% to 5%, based on the total mass of the negative electrode film layer. When the mass content of the adsorbent polymer is in the above range, the adsorbent polymer can effectively improve the interface performance and structural stability of the negative electrode sheet.

[0190] For example, the mass content of the adsorbent polymer was 0.05%, 0.08%, 0.10%, 0.11%, 0.12%, 0.15%, 0.16%, 0.18%, 0.20%, 0.22%, 0.25%, 0.28%, 0.30%, 0.32%, 0.35%, 0.38%, 0.40%, 0.42%, 0.45%, 0.48%, 0.50%, 0.55%, 0.58%, 0.60%, 0.70%, 0.80%, 0.90%, 0.95%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 1.10%, 1.11%, 1.12%, 1.13%, 1.14%, 1.15%, 1.16%, 1.17%, 1.18%, 1.19%, 1.20%, 1.21%, 1.22%, 1.23%, 1.24%, 1.25%, 1.26%, 1.27%, 1.28%, 1.29%, 1.29%, 1.30%, 1.31%, 1.32%, 1.33%, 1.34%, 1.35%, 1.36%, 1.37%, 1.38%, 1.39 ... , 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5.0%, or a range consisting of any two of the above values.

[0191] In some embodiments, the coating weight of the adsorbent polymer is 0.5 mg / 1540.25 mm 2 ~5mg / 1540.25mm 2 For example, 0.5 mg / 1540.25 mm 2 , 0.6mg / 1540.25mm 2 , 0.7mg / 1540.25mm 2 , 0.8mg / 1540.25mm 2 , 0.9mg / 1540.25mm 2 , 1.0mg / 1540.25mm 2 , 1.1mg / 1540.25mm 2 , 1.2mg / 1540.25mm 2 , 1.3mg / 1540.25mm 2 , 1.4mg / 1540.25mm 2 , 1.5mg / 1540.25mm 2 , 1.6mg / 1540.25mm 2 , 1.7mg / 1540.25mm 2 , 1.8mg / 1540.25mm 2 , 1.9mg / 1540.25mm 2 , 2.0mg / 1540.25mm2 , 2.1mg / 1540.25mm 2 , 2.2mg / 1540.25mm 2 , 2.3mg / 1540.25mm 2 , 2.4mg / 1540.25mm 2 , 2.5mg / 1540.25mm 2 , 2.6mg / 1540.25mm 2 , 2.7mg / 1540.25mm 2 , 2.8mg / 1540.25mm 2 , 2.9mg / 1540.25mm 2 , 3.0mg / 1540.25mm 2 , 3.1mg / 1540.25mm 2 , 3.2mg / 1540.25mm 2 , 3.3mg / 1540.25mm 2 , 3.4mg / 1540.25mm 2 , 3.5mg / 1540.25mm 2 , 3.6mg / 1540.25mm 2 , 3.7mg / 1540.25mm 2 , 3.8mg / 1540.25mm 2 , 3.9mg / 1540.25mm 2 , 4.0mg / 1540.25mm 2 , 4.1mg / 1540.25mm 2 , 4.2mg / 1540.25mm 2 , 4.3mg / 1540.25mm 2 , 4.4mg / 1540.25mm 2 , 4.5mg / 1540.25mm 2 , 4.6mg / 1540.25mm 2 , 4.7mg / 1540.25mm 2 , 4.8mg / 1540.25mm 2 , 4.9mg / 1540.25mm 2 , 5.0mg / 1540.25mm 2 or a range consisting of any two of the above values. The coating weight of the adsorbent polymer is the coating weight on one side of the negative electrode film layer of the negative electrode sheet.

[0192] The negative electrode active material may be any negative electrode active material for battery cells known in the art. For example, the negative electrode active material may include, but is 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 may include at least one of silicon elemental, silicon oxide, silicon-carbon composite, silicon-nitrogen composite, and silicon alloy material. The tin-based material may include at least one of tin elemental, tin oxide, and tin alloy material.

[0193] In some embodiments, the negative electrode current collector has two opposing surfaces in the thickness direction thereof, and the negative electrode film layer is provided on either or both of the two opposing surfaces of the negative electrode current collector.

[0194] In some embodiments, the negative electrode film layer optionally further comprises a negative electrode conductive agent. In the embodiments of the present application, the type of the negative electrode conductive agent is not particularly limited. For example, the negative electrode conductive agent may comprise 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 content of the negative electrode conductive agent is 5% or less based on the total mass of the negative electrode film layer.

[0195] In some embodiments, the negative electrode film layer optionally further includes a negative electrode adhesive. In the embodiments of the present application, the type of negative electrode adhesive is not particularly limited. For example, the negative electrode adhesive may include at least one of styrene butadiene rubber (SBR), water-soluble unsaturated resin (SR-1B), water-based acrylic resin (e.g., polyacrylic acid (PAA), polymethyl methacrylate (PMAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS). In some embodiments, the mass content of the negative electrode adhesive is 5% or less based on the total mass of the negative electrode film layer.

[0196] In some embodiments, the negative electrode film layer optionally further contains 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 mass content of the other additives is 2% or less based on the total mass of the negative electrode film layer.

[0197] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. An example of a metal foil is copper foil. The composite current collector may include a polymeric substrate and a metal layer formed on at least one surface of the polymeric substrate. The metal layer may include, for example, at least one of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. For example, the polymeric substrate layer may include at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0198] The negative electrode film layer is typically formed by applying a negative electrode slurry to a negative electrode current collector, drying, and cold pressing. The negative electrode slurry is typically formed by dispersing the negative electrode active material, adsorptive polymer, optional conductive agent, optional adhesive, and other optional additives in a solvent and stirring the mixture uniformly. The solvent may be, but is not limited to, N-methylpyrrolidone (NMP) or deionized water. Of course, the method for producing the negative electrode sheet is not limited to the above method, and the previously described production methods may also be used.

[0199] The negative electrode sheet may also include additional functional layers other than the negative electrode film layer. For example, in some embodiments, the negative electrode sheet of the present application further includes a conductive undercoating (e.g., composed of a conductive agent and an adhesive) sandwiched between the negative electrode current collector and the negative electrode film layer and provided on the surface of the negative electrode current collector. In other embodiments, the negative electrode sheet of the present application further includes a protective layer covering the surface of the negative electrode film layer. Battery cell

[0200] According to a second aspect, an embodiment of the present application further provides a battery cell, which includes a positive electrode sheet according to any one of the embodiments of the first aspect of the present application, and can effectively improve the cycle performance of the battery cell. [Separator]

[0201] In some embodiments, the battery cell includes a separator.

[0202] In some embodiments, the separator comprises a substrate.

[0203] In some embodiments, the separator includes a substrate and a coating disposed on at least one surface of the substrate.

[0204] In the embodiment of the present application, the material of the substrate is not particularly limited and can be any known substrate having good chemical and mechanical stability, such as at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The substrate can be a single-layer film or a multi-layer composite film. When the substrate is a multi-layer composite film, the materials of each layer can be the same or different.

[0205] In some embodiments, the coating may further include a heat-resistant filler, which may include at least one of inorganic particles and organic particles.

[0206] In some embodiments, the heat-resistant filler may have a decomposition temperature of 200° C. or higher, and therefore has excellent thermal stability and is less likely to decompose, which can further improve the heat resistance of the separator.

[0207] The inorganic particles have excellent 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 ion conductivity but not occluding ions, and inorganic particles capable of electrochemical reactions.

[0208] Optionally, the inorganic particles having a dielectric constant of 5 or more include boehmite, alumina, 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 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 / 3 The coating composition includes at least one of PMN-PT, PO3-PbTiO3, and modified inorganic particles thereof. Optionally, the inorganic particles may be modified chemically and / or physically. Chemical modification includes modification with coupling agents (e.g., silane coupling agents, titanate coupling agents, etc.), surfactants, and polymer grafting. Physical modification may include mechanical dispersion, ultrasonic dispersion, high-energy treatment, etc. The modification treatment reduces the aggregation of inorganic particles and allows them to form a more stable and uniform spatial network structure with nanocellulose. Furthermore, selecting coupling agents, surfactants, or polymer-modified inorganic particles with specific functional groups can improve the wettability of the coating in the electrolyte and the adhesive strength between the coating and the substrate.

[0209] Optionally, inorganic particles having ion conductivity but not occluding ions include Li3PO4, lithium titanium phosphate (Li x1 Ti y1 (PO4)3), lithium aluminum titanium phosphate (Li x2 Al y2 Ti z1 (PO4)3), (LiAlTiP) x3 O y3 type glass, lithium lanthanum titanate (Li x4 La y4 TiO3), lithium germanium thiophosphate Li x5 Ge y5 P z2 S w , lithium nitride Li x6 N y6 , SiS2 type glass Li x7 Si y7 S z3 , and P2S5 type glass Li x8 P y8 S z4 and 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.

[0210] Since organic particles have excellent thermal stability and are difficult to decompose, they can improve the heat resistance of the separator. At the same time, when the internal temperature of the battery cell rises to the melting point of the organic particles due to overcharging or thermal abuse, etc., the organic particles melt and are sucked into the pores of the base material by capillary action, playing a role of sealing the pores and blocking the circuit, which helps to ensure the high safety performance of the battery cell.

[0211] In some embodiments, the organic particles include, but are not limited to, at least one of polyethylene particles, polypropylene particles, polystyrene particles, melamine resin particles, phenolic resin particles, polyester particles (e.g., polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate), polyimide particles, polyamideimide particles, polyaramid particles, polyphenylene sulfide particles, polysulfone particles, polyethersulfone particles, polyetheretherketone particles, polyaryletherketone particles, and copolymers of butyl acrylate and ethyl methacrylate (e.g., crosslinked polymers of butyl acrylate and ethyl methacrylate).

[0212] In some embodiments, the coating further includes an adhesive. In the present application, the type of adhesive is not particularly limited, and any known material having good adhesive properties can be selected. For example, the adhesive 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 of other comonomers), polyvinyl alcohol, an isobutylene-maleic anhydride copolymer, and polyacrylamide.

[0213] Optionally, the content of adhesive in the coating is less than 30% based on the weight of the coating. [Electrolyte]

[0214] In some embodiments, the battery cell includes an electrolyte.

[0215] During the charge and discharge process of the battery cell, active ions move back and forth between the positive and negative electrode sheets to be absorbed and desorbed, and the electrolyte serves to conduct the active ions between the positive and negative electrode sheets. In this application, the type of electrolyte is not particularly limited and can be selected according to actual needs.

[0216] The electrolyte solution includes an electrolyte salt and a solvent, and the types of the electrolyte salt and the solvent are not particularly limited and can be selected according to actual needs.

[0217] For example, the electrolyte salt may include, but is not limited to, at least one of lithium hexafluorophosphate (LiPF), lithium tetrafluoroborate (LiBF), lithium perchlorate (LiClO), lithium hexafluoroarsenate (LiAsF), lithium bis(fluorosulfonyl)imide (LiFSi), lithium bis(trifluoromethanesulfonyl)imide (LiTFSi), lithium trifluoromethanesulfonate (LiTFS), lithium borate difluorooxalate (LiDFOB), lithium bis(oxalato)borate (LiBOB), lithium difluorophosphate (LiPOF), lithium difluorodisalophosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0218] For example, the solvent may include, but is not limited to, at least one 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), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

[0219] In some embodiments, the electrolyte solution optionally further contains an additive. For example, the additive may include a negative electrode film-forming additive, a positive electrode film-forming additive, or an additive capable of improving some performance of the battery, such as the overcharge performance of the battery, the high-temperature performance of the battery, or the low-temperature power performance of the battery.

[0220] In some embodiments, the positive electrode sheet, separator, and negative electrode sheet can be fabricated into an electrode assembly by a winding or lamination process.

[0221] In some embodiments, the battery cell may include an exterior structure that can be used to package the electrode assembly and electrolyte.

[0222] In some embodiments, the exterior structure of the battery cell may be a hard case such as a hard plastic case, an aluminum case, or a steel case. The exterior structure of the battery cell may be a soft pack, for example, a bag-shaped soft pack. The material of the soft bag may be plastic, for example, at least one of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0223] In the present application, the shape of the battery cell is not particularly limited, and may be cylindrical, rectangular, or any other shape. Figure 1 shows a battery cell 5 having a rectangular structure as an example.

[0224] In some embodiments, as shown in FIGS. 1 and 2 , the exterior structure may include a housing 51 and a cover plate 53. The housing 51 may include a bottom plate and a side plate connected to the bottom plate, with a storage cavity formed between the bottom plate and the side plate. The housing 51 has an opening communicating with the storage cavity, and the cover plate 53 covers the opening to seal the storage cavity. The positive electrode sheet, the negative electrode sheet, and the separator may be manufactured into an electrode assembly 52 by a winding process and / or a stacking process. The electrode assembly 52 is packaged within the storage cavity. The electrode assembly 52 is impregnated with an electrolyte. The number of electrode assemblies 52 included in the battery cell 5 may be one or more, and may be increased or decreased depending on needs.

[0225] The method for manufacturing a battery cell of the present application is a known method. In some embodiments, the battery cell is assembled with a positive electrode sheet, a separator, a negative electrode sheet, and an electrolyte. For example, the positive electrode sheet, the separator, and the negative electrode sheet are subjected to a winding process and / or a stacking process to prepare an electrode assembly, and then the prepared electrode assembly is placed in an exterior structure, dried, and then an electrolyte is injected, and the battery cell is manufactured by carrying out processes such as vacuum packaging, standing, chemical conversion, and shaping.

[0226] In some embodiments of the present application, the battery cells according to the present application can be used to assemble a battery module. The number of battery cells included in the battery module can be one or more, and can be increased or decreased depending on the application and capacity of the battery module.

[0227] Fig. 3 is a schematic diagram of an example battery module 4. As shown in Fig. 3, in the battery module 4, the plurality of battery cells 5 may be arranged sequentially along the longitudinal direction of the battery module 4. Of course, they may be arranged in any other manner. Furthermore, the plurality of battery cells 5 may be fixed by fasteners.

[0228] Optionally, the battery module 4 may further include a case having an accommodation space in which the plurality of battery cells 5 are accommodated.

[0229] In some embodiments, the battery modules described above can be used to assemble a battery pack, and the number of battery modules included in the battery pack can be increased or decreased depending on the application and capacity of the battery pack.

[0230] Both the battery module 4 and the battery pack can be specific examples of the battery in the embodiments of the present application.

[0231] 4 and 5 are schematic diagrams of an example battery pack 1. As shown in FIGS. 4 and 5, the battery pack 1 may include a battery housing and a plurality of battery modules 4 provided within the battery housing. The battery housing includes an upper housing 2 and a lower housing 3, and the upper housing 2 is provided to cover the lower housing 3, forming an enclosed space for accommodating the battery modules 4. The plurality of battery modules 4 may be arranged in any manner within the battery housing. power consumption equipment

[0232] According to a third aspect, the present application provides a power consuming device including at least one of a battery cell, a battery module, and 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 unit for the power consuming device. The power consuming device may be, but is not limited to, a portable 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 an electrolyte, and when the battery cell is applied to a power consuming device, the fill hole is located at the bottom of the battery cell in the vertical direction. Since there is very little or even no free electrolyte in the battery cell, the reliability of use of the battery cell is improved, thereby contributing to the reliability of use of the power consuming device.

[0233] Furthermore, a power consuming device may select a battery cell, a battery module, or a battery pack depending on its usage needs. 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. Other examples of power consuming devices include mobile phones, tablet computers, and laptops. Since the power consuming device is usually required to be thin, a battery cell may be used as the power source. Example

[0234] Examples of the present application are described below. The examples described below are merely illustrative for interpreting the present application and should not be understood as limiting the present application. Unless otherwise specified, specific techniques and conditions in the examples are in accordance with the techniques, conditions, or specifications described in documents in the field. Reagents and equipment used are all commercially available general products unless the manufacturer is specified. Example A1: Manufacture of a lithium ion battery (using a fluoropolymer as the absorbent polymer) (1) Manufacturing of positive electrode sheets

[0235] An aluminum foil was used as the positive electrode current collector.

[0236] A positive electrode slurry was prepared by adding an absorbent polymer, a positive electrode active material, carbon black as a conductive agent, and polyvinylidene fluoride (PVDF) as an adhesive to N-methylpyrrolidone (NMP). The positive electrode slurry was applied to an aluminum foil current collector and dried at 85°C. The resulting material was then cold-pressed, trimmed, cut, and stripped. The positive electrode film layer formed on the positive electrode current collector was then dried under vacuum at 85°C for 4 hours to produce a positive electrode sheet. The mass ratio of the absorbent polymer, LiFePO4, carbon black, and PVDF contained in the positive electrode film layer was 0.5:96.8:2:0.7. The polyvinylidene fluoride (PVDF) adhesive had a crystallinity of 48%, a melting temperature of 164°C, and a glass transition temperature of 39°C. (2) Manufacturing of negative electrode sheets

[0237] Copper foil was used as the negative electrode current collector.

[0238] The negative electrode slurry was prepared by adding an absorbent polymer, artificial graphite (the negative electrode active material), carbon black (the conductive agent), styrene butadiene rubber (SBR) (the adhesive), and sodium hydroxymethylcellulose (CMC) (the thickener) to deionized water in a weight ratio of 2.5:94:0.5:2:1 and mixing them uniformly. The negative electrode slurry was applied to a copper foil current collector and dried at 85°C. After that, the negative electrode was cold-pressed, trimmed, cut, and stripped, and then dried under vacuum at 120°C for 12 hours to produce a negative electrode sheet. (3) Electrolyte production

[0239] 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) were mixed in a volume ratio of 3:7 to prepare an electrolyte solvent. This mixed solvent was then mixed with the lithium salt LiPF6 to produce an electrolyte with a lithium salt concentration of 1 mol / L. (4) Lithium-ion battery manufacturing

[0240] A polyethylene film (PE) was used as the separator. The positive electrode sheet, separator, and negative electrode sheet were stacked in this order, with the separator positioned between the positive and negative electrode sheets to provide isolation, and then wound to create an electrode assembly. The electrode assembly was placed in an outer case, dried, and then injected with electrolyte. The lithium-ion battery was manufactured by vacuum packaging, leaving it to stand, forming, and shaping. Examples A2 to A4

[0241] In Examples A2 to A4, lithium ion batteries were produced in the same manner as in Example A1, except that the type of adsorptive polymer was changed. Examples A5 to A6

[0242] In Examples A5 and A6, lithium ion batteries were produced in the same manner as in Example A1, except that the amount of the adsorptive polymer used was changed. Example A7 and Example A8

[0243] In Examples A7 and A8, lithium ion batteries were produced in the same manner as in Example A1, except that the type of adsorptive polymer was changed. Examples A9 to A15

[0244] In Examples A9 to A15, lithium ion batteries were produced in the same manner as in Example A1, except that the type and amount of the adsorptive polymer used were changed. Comparative Example A1

[0245] In Comparative Example A1, a lithium ion battery was fabricated in the same manner as in Example A1, except that neither the positive electrode sheet nor the negative electrode sheet contained an adsorptive polymer. (1) Manufacturing of positive electrode sheets

[0246] An aluminum foil was used as the positive electrode current collector.

[0247] A positive electrode slurry was prepared by adding the positive electrode active material, carbon black (a conductive agent), and polyvinylidene fluoride (PVDF) (an example of an adhesive) to N-methylpyrrolidone (NMP). The positive electrode slurry was applied to an aluminum foil current collector and dried at 85°C. After that, the cathode was cold pressed, trimmed, cut, and stripped. The cathode film layer formed on the cathode current collector was then dried under vacuum at 85°C for 4 hours to produce a positive electrode sheet. The mass ratio of LiFePO4, conductive carbon black, and PVDF in the positive electrode film layer was 96.8:2:1.2. (2) Manufacturing of negative electrode sheets

[0248] Copper foil was used as the negative electrode current collector.

[0249] The negative electrode slurry was prepared by adding the negative electrode active material (artificial graphite), the conductive agent (carbon black), the adhesive (styrene butadiene rubber (SBR)), and the thickener (sodium hydroxymethylcellulose (CMC)) to deionized water in a weight ratio of 96.5:0.5:2:1 and mixing them uniformly. The negative electrode slurry was then applied to a copper foil current collector and dried at 85°C. After that, the negative electrode was cold pressed, trimmed, cut, and stripped, and then dried under vacuum at 120°C for 12 hours to produce a negative electrode sheet. (Comparative example A2)

[0250] In Comparative Example A2, a lithium ion battery was produced in the same manner as in Example A1, except that the type of polymer was changed. Testing part 1. Lithium-ion battery capacity retention test

[0251] The operating voltage of the battery is V1 to V2, and in the case of LiFePO4, V1=2.0V and V2=3.8V.

[0252] The lithium-ion batteries manufactured in the Examples and Comparative Examples were first subjected to capacity determination. C0 was tested by the following steps: discharge to V1 at 1C, allow to stand for 5 minutes, then charge to V2 at a constant current of 1 / 3C, further charge to a constant voltage of V2 until the current reached 0.05C, allow to stand for 5 minutes, and then discharge to V1 at 1C. The discharge capacity at this time was designated C0.

[0253] The battery was then charged to V2 at room temperature using a multi-stage charging method equivalent to 1.2C (i.e., charging to 0.5C0 (Ah) at a constant current of 1.2C, then charging to 0.3C0 (Ah) at a constant current of 0.87C, and finally charging to V2 at a constant current of 1 / 3C). It was then further charged at a constant voltage of V2 until the current reached 0.05C, allowed to stand for 5 minutes, and then discharged to V1 at 0.33C. The resulting capacity was designated as the initial capacity C0, and the initial clamping force of the lithium-ion battery was set to 15,000 (N). The above steps were repeated for the same battery, and the discharge capacity Cn of the battery after n cycles was recorded. In this case, the battery capacity retention rate after each cycle is Pn = Cn / C0 * 100%, and if the values of 200 points including P1, P2,...,P200 are taken as the ordinate and the corresponding number of cycles as the abscissa, a graph showing the corresponding battery capacity retention rate and number of cycles for the polymers of the examples and comparative examples can be obtained.

[0254] In this test process, the first cycle corresponds to n=1, the second cycle corresponds to n=2, ... the 200th cycle corresponds to n=200. For example, the battery capacity retention rate data for the Examples shown in Tables 1 to 4 is the data measured after 200 cycles under the above test conditions, i.e., the P200 value. The test process for the Comparative Example and other Examples is the same as the above process. 2. DC impedance test of lithium-ion batteries

[0255] The operating voltage of the battery is V1 to V2, and in the case of LiFePO4, V1=2.0V and V2=3.8V.

[0256] The lithium-ion batteries manufactured in the Examples and Comparative Examples were first subjected to capacity determination. C0 was tested by the following steps: discharge to V1 at 1C, allow to stand for 5 minutes, then charge to V2 at a constant current of 1 / 3C, further charge to a constant voltage of V2 until the current reached 0.05C, allow to stand for 5 minutes, and then discharge to V1 at 1C. The discharge capacity at this time was designated C0.

[0257] The lithium-ion batteries prepared in the Examples and Comparative Examples were charged to V2 at 25°C using a multi-stage charging method equivalent to 1.2C (i.e., charging to 0.5C0 (Ah) at a constant current of 1.2C, then charging to 0.3C0 (Ah) at a constant current of 0.87C, and finally charging to V2 at a constant current of 1 / 3C). The batteries were then further charged at a constant voltage of V2 until the current reached 0.05C. After allowing to stand for 5 minutes, the voltage V3 was recorded. The batteries were then discharged at 1 / 3C for 30 seconds, and the voltage V2 was recorded. The internal resistance DCR1 of the battery after the first cycle was calculated based on (V3 - V2) / (1 / 3C). The above steps were repeated for the same battery, and the internal resistance DCRn (n=1, 2, 3...200) of the battery after n cycles was recorded. The values of the 200 points including DCR1, DCR2, DCR3...DCR200 were plotted on the ordinate and the corresponding cycle number on the abscissa, and a graph showing the corresponding battery discharge DCIR and cycle number for the polymers of the examples and comparative examples was obtained.

[0258] In this test process, the first cycle corresponds to n = 1, the second cycle corresponds to n = 2, ... the 200th cycle corresponds to n = 200. For example, the increase rate of the internal resistance of the battery of the example shown in Tables 1 to 4 = (DCRn - DCR1) / DCR1 * 100%, and the test process of the comparative example and other examples is the same as the above process.

[0259] The data in Tables 1 to 4 were measured after 200 cycles under the above test conditions. Test results

[0260] [Table 1]

[0261] In Table 1, VDF stands for vinylidene fluoride, HFP stands for hexafluoropropylene, and TFE stands for tetrafluoroethylene. 90% VDF means that the molar content of VDF is 90% based on the total molar amount of VDF and HFP, and 10% FEP means that the molar content of FEP is 10%. Even for polymers polymerized from the same type of monomer, changes in polymerization conditions (polymerization temperature, polymerization pressure, etc.) can change the glass transition temperature and other properties of the polymers.

[0262] As can be seen from Table 1, compared to Comparative Example A1, in the Examples of the present application, adding the polymer of the present application to the positive electrode sheet and / or negative electrode sheet improved the cycling performance of lithium-ion batteries. Compared to Comparative Example A2, in the Examples of the present application, when the conditions 3≦m1 / n≦35 and 1.00≦m2 / n≦1.05 are satisfied, the molecular chain arrangement is likely to be sparse, the interchain forces are weak, and adjacent molecular chains are likely to be cleaved. Segmental motion due to intramolecular rotation forms a highly flexible molecular chain structure, physically adsorbing the electrolyte onto the surface of the active material particles, achieving a liquid locking effect and improving the infiltration of the electrolyte into the electrode sheet. Even in a liquid-starved environment such as high temperature or dryness of the battery system, the electrolyte can be flexibly released, increasing the deformability of the interface between the polymer and the active material, cushioning deformation of the interface between the adsorbent polymer and the active material during the battery charge / discharge cycle, improving the structural stability of the electrode sheet and improving the cycling performance of the battery. Example B1: Manufacture of a lithium ion battery (using an ether-based polymer as the absorbent polymer) (1) Manufacturing of positive electrode sheets

[0263] An aluminum foil was used as the positive electrode current collector.

[0264] A positive electrode slurry was prepared by adding an ether polymer, a positive electrode active material LiFePO4, a conductive agent carbon black, and an adhesive polyvinylidene fluoride (PVDF) to N-methylpyrrolidone (NMP) in a mass ratio of 0.5:96.8:2:0.7. The positive electrode slurry was applied to an aluminum foil current collector and dried at 85°C. The resulting sheet was then cold pressed, trimmed, cut, and stripped. The sheet was then dried under vacuum at 85°C for 4 hours to produce a positive electrode sheet. The adhesive polyvinylidene fluoride (PVDF) had a crystallinity of 48%, a melting temperature of 164°C, and a glass transition temperature of 39°C. (2) Manufacturing of negative electrode sheets

[0265] Copper foil was used as the negative electrode current collector.

[0266] The negative electrode slurry was prepared by adding an ether polymer, artificial graphite (as the negative electrode active material), carbon black, styrene butadiene rubber (SBR) as an adhesive, and sodium hydroxymethylcellulose (CMC) as a thickener to deionized water in a weight ratio of 2.5:94:0.5:2:1 and mixing them uniformly. The negative electrode slurry was applied to a copper foil current collector and dried at 85°C. After that, the foil was cold pressed, trimmed, cut, and stripped, and then dried under vacuum at 120°C for 12 hours to produce a negative electrode sheet. (3) Preparation of electrolyte

[0267] 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) were mixed in a volume ratio of 3:7 to prepare an electrolyte solvent. This mixed solvent was then mixed with the lithium salt LiPF6 to produce an electrolyte with a lithium salt concentration of 1 mol / L. (4) Lithium-ion battery manufacturing

[0268] A polyethylene film (PE) was used as the separator. The positive electrode sheet, separator, and negative electrode sheet were stacked in this order, with the separator positioned between the positive and negative electrode sheets to provide isolation, and then wound to create an electrode assembly. The electrode assembly was placed in an outer case, dried, and then injected with electrolyte. The lithium-ion battery was manufactured by vacuum packaging, leaving it to stand, forming, and shaping. Comparative Example B1

[0269] In Comparative Example B1, a lithium ion battery was produced in the same manner as in Example B1, except that the positive electrode sheet did not contain an ether-based polymer and the negative electrode sheet did not contain an ether-based polymer. Comparative example B2

[0270] In Comparative Example B2, a lithium ion battery was produced in the same manner as in Example B1, except that the materials of the ether-based polymers were changed between the positive electrode sheet and the negative electrode sheet. Examples B2 to B4

[0271] In Examples B2 to B4, lithium ion batteries were produced in the same manner as in Example B1, except that the ether polymer material was changed between the positive electrode sheet and the negative electrode sheet. Example B5

[0272] In Example B5, a lithium ion battery was produced in the same manner as in Example B1, except that the positive electrode sheet contained an ether-based polymer, but the negative electrode sheet did not contain an ether-based polymer. Examples B6 to B9

[0273] In Examples B6 to B9, lithium ion batteries were produced in the same manner as in Example B1, except that the content of the ether-based polymer in the positive electrode sheet was changed. Examples B10 to B12

[0274] In Examples B10 to B12, lithium ion batteries were produced in the same manner as in Example B1, except that the content of the ether-based polymer in the negative electrode sheet was changed.

[0275] The performance evaluation method of the lithium-ion battery was the same as the test section above.

[0276] Table 2 shows data for Examples and Comparative Examples, and performance test results for lithium ion batteries.

[0277] [Table 2]

[0278] In Table 2, 100% oxirane means that the mass content of oxirane is 100% based on the total mass of Monomer 1 and Monomer 2.

[0279] 80% oxirane means that the mass content of oxirane is 80% relative to the total mass of Monomer 1 and Monomer 2, and 20% ethyl oxirane-2-carboxylate means that the mass content of ethyl oxirane-2-carboxylate is 20% relative to the total mass of Monomer 1 and Monomer 2.

[0280] As can be seen from Table 2, compared to Comparative Example B1, in the Examples of the present application, the addition of the ether-based polymer of the present application to the positive electrode sheet and / or negative electrode sheet improved the cycling performance of lithium-ion batteries. Compared to Comparative Example B2, in the Examples of the present application, when the conditions 3≦m1 / n≦35 and 1.00≦m2 / n≦1.05 are satisfied, the molecular chain arrangement is likely to be sparse, the interchain forces are weak, and adjacent molecular chains are likely to be cleaved. Segmental motion due to intramolecular rotation forms a highly flexible molecular chain structure, physically adsorbing the electrolyte onto the surface of the active material particles, achieving a liquid locking effect and improving the infiltration of the electrolyte into the electrode sheet. Even in a liquid-starved environment such as high temperature or dryness of the battery system, the electrolyte can be flexibly released, increasing the deformability of the interface between the polymer and the active material, cushioning deformation of the interface between the adsorbent polymer and the active material during battery charge / discharge cycles, improving the structural stability of the electrode sheet and improving the cycling performance of the battery. Example C1: Manufacture of a lithium ion battery (using an ester polymer as the absorbent polymer) (1) Manufacturing of positive electrode sheets

[0281] An aluminum foil was used as the positive electrode current collector.

[0282] A positive electrode slurry was prepared by adding an ester polymer, LiFePO4 (positive electrode active material), carbon black (conductive agent), and polyvinylidene fluoride (adhesive) to N-methylpyrrolidone (NMP) in a mass ratio of 0.5:96.8:2:0.7. The positive electrode slurry was applied to an aluminum foil current collector and dried at 85°C. The resulting sheet was then cold pressed, trimmed, cut, and stripped. The sheet was then dried under vacuum at 85°C for 4 hours to produce a positive electrode sheet. The polyvinylidene fluoride (PVDF) adhesive had a crystallinity of 48%, a melting temperature of 164°C, and a glass transition temperature of 39°C. (2) Manufacturing of negative electrode sheets

[0283] Copper foil was used as the negative electrode current collector.

[0284] The negative electrode slurry was prepared by adding ester polymer, artificial graphite (negative electrode active material), carbon black (conductive agent), styrene butadiene rubber (SBR) (adhesive), and sodium hydroxymethylcellulose (CMC) (thickener) to deionized water in a weight ratio of 2.5:94:0.5:2:1 and mixing uniformly. The negative electrode slurry was applied to a copper foil current collector and dried at 85°C. After that, the negative electrode was cold pressed, trimmed, cut, and stripped, and then dried under vacuum at 120°C for 12 hours to produce a negative electrode sheet. (3) Preparation of electrolyte

[0285] 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) were mixed in a volume ratio of 3:7 to prepare an electrolyte solvent. This mixed solvent was then mixed with the lithium salt LiPF6 to produce an electrolyte with a lithium salt concentration of 1 mol / L. (4) Lithium-ion battery manufacturing

[0286] A polyethylene film (PE) was used as the separator. The positive electrode sheet, separator, and negative electrode sheet were stacked in this order, with the separator positioned between the positive and negative electrode sheets to provide isolation, and then wound to form an electrode assembly. The formed electrode assembly was placed in an outer case, dried, and then injected with an electrolyte. The lithium-ion battery was manufactured by vacuum packaging, leaving it to stand, forming, and shaping. Comparative Example C1

[0287] In Comparative Example C1, a lithium ion battery was produced in the same manner as in Example C1, except that the positive electrode sheet did not contain an ester-based polymer and the negative electrode sheet did not contain an ester-based polymer. Comparative Example C2

[0288] In Comparative Example C2, a lithium ion battery was produced in the same manner as in Example C1, except that the ester polymer material was changed between the positive electrode sheet and the negative electrode sheet. Examples C2 to C4

[0289] In Examples C2 to C4, lithium ion batteries were produced in the same manner as in Example C1, except that the ester polymer material was changed between the positive electrode sheet and the negative electrode sheet. Example C5

[0290] In Example C5, a lithium ion battery was produced in the same manner as in Example C1, except that the positive electrode sheet contained an ester-based polymer, but the negative electrode sheet did not contain an ester-based polymer. Examples C6 to C9

[0291] In Examples C6 to C9, lithium ion batteries were produced in the same manner as in Example C1, except that the content of the ester polymer in the positive electrode sheet was changed. Examples C10 to C12

[0292] In Examples C10 to C12, lithium ion batteries were produced in the same manner as in Example C1, except that the content of the ester polymer in the negative electrode sheet was changed.

[0293] The performance evaluation method of the lithium-ion battery was the same as the test section above.

[0294] Table 3 shows data for Examples and Comparative Examples, and performance test results for lithium ion batteries.

[0295] [Table 3]

[0296] In Table 3, 100% methyl methacrylate means that the mass content of methyl methacrylate is 100% based on the total mass of Monomer 1, Monomer 2 and Monomer 3.

[0297] 85% vinyl acetate means that the mass content of vinyl acetate is 85% based on the total mass of Monomer 1, Monomer 2, and Monomer 3, and 15% ethylene means that the mass content of ethylene is 15% based on the total mass of Monomer 1, Monomer 2, and Monomer 3.

[0298] As can be seen from Table 3, compared to Comparative Example C1, in Example C of the present application, the addition of the ester-based polymer of the present application to the positive electrode sheet and / or negative electrode sheet improved the cycling performance of the lithium-ion battery. Compared to Comparative Example C2, in the Examples of the present application, when the conditions 3≦m1 / n≦35 and 1.00≦m2 / n≦1.05 are satisfied, the molecular chain arrangement is likely to be sparse, the interchain forces are weak, and adjacent molecular chains are likely to be cleaved. Segmental motion due to intramolecular rotation forms a highly flexible molecular chain structure, physically adsorbing the electrolyte onto the surface of the active material particles, achieving a liquid locking effect and improving the infiltration of the electrolyte into the electrode sheet. Even in a liquid-starved environment such as high temperature or dryness of the battery system, the electrolyte can be flexibly released, increasing the deformability of the interface between the polymer and the active material, cushioning deformation of the interface between the adsorbent polymer and the active material during the battery charge / discharge cycle, improving the structural stability of the electrode sheet and improving the cycling performance of the battery. Example D1: Manufacture of a lithium ion battery (using an aldehyde ketone polymer as the absorbent polymer) (1) Manufacturing of positive electrode sheets

[0299] An aluminum foil was used as the positive electrode current collector.

[0300] The positive electrode slurry was prepared by adding an aldehyde ketone polymer, LiFePO4 (positive electrode active material), carbon black (conductive agent), and polyvinylidene fluoride (PVDF) (adhesive) to N-methylpyrrolidone (NMP) in a mass ratio of 0.5:96.8:2:0.7. The positive electrode slurry was applied to an aluminum foil current collector and dried at 85°C. The resulting sheet was then cold pressed, trimmed, cut, and stripped. The sheet was then dried under vacuum at 85°C for 4 hours to produce a positive electrode sheet. The polyvinylidene fluoride (PVDF) adhesive had a crystallinity of 48%, a melting temperature of 164°C, and a glass transition temperature of 39°C. (2) Manufacturing of negative electrode sheets

[0301] Copper foil was used as the negative electrode current collector.

[0302] The aldehyde ketone polymer, artificial graphite (anode active material), carbon black (conductive agent), styrene butadiene rubber (SBR) (adhesive), and sodium hydroxymethylcellulose (CMC) (thickener) were mixed in a weight ratio of 2.5:94:0.5:2:1 with deionized water to prepare anode slurry. The resulting slurry was applied to a copper foil current collector and dried at 85°C. The resulting foil was then cold pressed, trimmed, cut, and stripped, and then dried under vacuum at 120°C for 12 hours to produce anode sheets. (3) Preparation of electrolyte

[0303] 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) were mixed in a volume ratio of 3:7 to form an electrolyte solvent, and then this mixed solvent was mixed with the lithium salt LiPF6 to produce an electrolyte with a lithium salt concentration of 1 mol / L. (4) Lithium-ion battery manufacturing

[0304] A polyethylene film (PE) was used as the separator. The positive electrode sheet, separator, and negative electrode sheet were stacked in this order, with the separator positioned between the positive and negative electrode sheets to provide isolation, and then wound to create an electrode assembly. The electrode assembly was placed in an outer case, dried, and then injected with electrolyte. The lithium-ion battery was manufactured by vacuum packaging, leaving it to stand, forming, and shaping. Comparative Example D1

[0305] In Comparative Example D1, a lithium ion battery was produced in the same manner as in Example D1, except that the positive electrode sheet did not contain an aldehyde ketone polymer and the negative electrode sheet did not contain an aldehyde ketone polymer. Comparative example D2

[0306] In Comparative Example D2, a lithium ion battery was produced in the same manner as in Example D1, except that the material of the aldehyde ketone polymer was changed between the positive electrode sheet and the negative electrode sheet. Examples D2 to D4

[0307] In Examples D2 to D4, lithium ion batteries were produced in the same manner as in Example D1, except that the material of the aldehyde ketone polymer was changed between the positive electrode sheet and the negative electrode sheet. Example D5

[0308] In Example D5, a lithium ion battery was produced in the same manner as in Example D1, except that the positive electrode sheet contained an ether-based polymer, but the negative electrode sheet did not contain an ether-based polymer. Examples D6 to D9

[0309] In Examples D6 to D9, lithium ion batteries were produced in the same manner as in Example D1, except that the content of the aldehyde ketone polymer in the positive electrode sheet was changed. Examples D10 to D12

[0310] In Examples D10 to D12, lithium ion batteries were produced in the same manner as in Example D1, except that the content of the aldehyde ketone polymer in the negative electrode sheet was changed.

[0311] The performance evaluation method of the lithium-ion battery was the same as the test section above.

[0312] Table 4 shows data for Examples and Comparative Examples, and performance test results for lithium ion batteries.

[0313] [Table 4]

[0314] In Table 4, 100% formaldehyde means that the mass content of formaldehyde is 100% based on the total mass of Monomer 1 and Monomer 2.

[0315] 30% polyvinyl alcohol means that the polyvinyl alcohol content is 30% by weight, based on the combined weight of Monomer 1 and Monomer 2.

[0316] As can be seen from Table 4, compared to Comparative Example D1, in the Examples of the present application, the addition of the aldehyde ketone polymer of the present application to the positive electrode sheet and / or negative electrode sheet improved the cycling performance of lithium-ion batteries. Compared to Comparative Example D2, in the Examples of the present application, when the conditions 3≦m1 / n≦35 and 1.00≦m2 / n≦1.05 are satisfied, the molecular chain arrangement is likely to be sparse, the interchain forces are weak, and adjacent molecular chains are likely to be cleaved. Segmental motion due to intramolecular rotation forms a highly flexible molecular chain structure, physically adsorbing the electrolyte onto the surface of the active material particles, achieving a liquid locking effect and improving the infiltration of the electrolyte into the electrode sheet. Even in a liquid-starved environment such as high temperature or dryness of the battery system, the electrolyte can be flexibly released, increasing the deformability of the interface between the polymer and the active material, buffering deformation of the interface between the adsorbent polymer and the active material during battery charge / discharge cycles, improving the structural stability of the electrode sheet and improving the cycling performance of the battery.

[0317] Although the embodiments have been shown and described above, it should be understood by those skilled in the art that the above embodiments should not be construed as limitations on the present application, and that various changes, substitutions, and alterations are possible without departing from the spirit, principle, and scope of the present application.

Claims

1. A current collector; a film layer provided on at least one side of the current collector and containing an active material and an adsorptive polymer; The adsorbent polymer has a molecular weight of 3≦m １ / n ≦ 35, the mass n of the adsorbent polymer is in g, and the mass m of the first substance １ has units of g, The first substance is At 45°C, an absorbent polymer is added to a predetermined electrolyte solution to form a polymer system, the mass ratio of the predetermined electrolyte solution to the absorbent polymer is 1:15, the predetermined electrolyte solution includes dimethyl carbonate, ethyl methyl carbonate, ethylene carbonate, and lithium hexafluorophosphate, the dimethyl carbonate, ethyl methyl carbonate, and ethylene carbonate have the same mass, and the concentration of lithium hexafluorophosphate is 1 mol / L; The polymer system is left at 45°C for 60 hours, left at 25°C for 24 hours or more, and then filtered through a 200 mesh filter to leave a first substance; The adsorbent polymer has a viscosity of 1.00≦m ２ / n≦1.05, and the mass m of the second substance ２ has units of g, The electrode sheet, wherein the second material is obtained after drying the first material at 60°C for 24 hours or more.

2. 5≦m １ 2. The electrode sheet according to claim 1, wherein / n≦35.

3. the mass content of the adsorbent polymer is 5% or less, based on the total mass of the film layer; and / or The coating weight of the adsorbent polymer was 0.5 mg / 1540.25 mm ２ ~2mg / 1540.25mm ２ The electrode sheet according to claim 1 or 2,

4. The electrode sheet according to any one of claims 1 to 3, wherein the mass content of the adsorbent polymer is 0.05% to 5% based on the total mass of the film layer.

5. The adsorbent polymer comprises a fluoropolymer, and the fluoropolymer has a crystallinity X by differential scanning calorimetry. ｃ１ (%) is 0 < X ｃ１ ≦30, The melting temperature T of the fluoropolymer ｍ１ (°C) is 0 < T ｍ１ The electrode sheet according to any one of claims 1 to 4, wherein the surface roughness is ≦140.

6. The glass transition temperature T ｇ１ (°C) is -150≦T ｇ１ The electrode sheet according to claim 5, wherein the surface roughness is ≦60.

7. The fluoropolymer contains at least one compound selected from the group consisting of compounds represented by formula (AI) to (AIII), 【Chemical 1】 In formula (AI) and formula (AII), R １１ , R １２ , R １３ and R １４ each independently contains a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a substituted or unsubstituted C1 to C3 alkyl group, or a substituted or unsubstituted C1 to C3 alkoxy group, and R １１ , R １２ , R １３ and R １４ at least one of which contains a fluorine atom; 【Chemistry 2】 In formula (AIII), R １５ contains a single bond or a substituted or unsubstituted C1 to C3 alkyl group, p is selected from any positive integer of 1 to 3, and n is selected from any positive integer of 1000 to 30000. The electrode sheet according to claim 5 or 6.

8. The adsorbent polymer includes an ether-based polymer, and a sheet-like structure manufactured from the ether-based polymer is subjected to a process of (T ｍ２ +20°C, a dynamic frequency scan test was performed to obtain a modulus of elasticity G'-loss modulus of elasticity G'' curve, and the slope K １ is 1<K １ <∞, and T ｍ２ The electrode sheet according to any one of claims 1 to 7, wherein (°C) represents the melting temperature of the ether-based polymer.

9. 1<K １ 9. The electrode sheet according to claim 8, wherein the tensile strength is ≦100.

10. 1<K １ The electrode sheet according to claim 9, wherein the ρ is ≦10.

11. The glass transition temperature T ｇ２ (°C) is -100≦T ｇ２ The electrode sheet according to any one of claims 8 to 10, wherein the average molecular weight is ≦50.

12. The ether-based polymer contains at least one of a compound represented by formula (BI) and a compound represented by formula (BII), 【Chemistry 3】 In formula (BI), R ２１ and R ２２ each independently contains a hydrogen atom, a substituted or unsubstituted C1 to C3 alkyl group, or a substituted or unsubstituted C1 to C3 alkoxy group; R ２３ contains a substituted or unsubstituted C1 to C5 alkylene group, 【Chemistry 4】 In formula (BII), R ２４ ~R ２７ each independently contains a hydrogen atom, a substituted or unsubstituted C1 to C3 alkyl group, a substituted or unsubstituted C1 to C3 alkoxy group, or an ether group; R ２４ ~R ２７ at least one of contains a substituted or unsubstituted C1-C3 alkoxy group or ether group; The electrode sheet according to any one of claims 8 to 11, wherein the degree of polymerization n of the ether-based polymer is selected from any positive integer of 1,500 to 25,000.

13. The adsorbent polymer includes an ester-based polymer, and the sheet-like structure produced from the ester-based polymer is ｍ３ +20°C, a dynamic frequency scan test was performed to obtain a modulus of elasticity G'-loss modulus of elasticity G'' curve, and the slope K ２ is 1<K ２ <∞, and T ｍ３ The electrode sheet according to any one of claims 1 to 12, wherein (°C) represents the melting temperature of the ester-based polymer.

14. 1<K ２ 14. The electrode sheet according to claim 13, wherein the tensile strength is ≦100.

15. 1<K ２ 15. The electrode sheet according to claim 14, wherein the tensile strength is ≦10.

16. The glass transition temperature T ｇ３ (°C) is -100≦T ｇ３ The electrode sheet according to any one of claims 13 to 15, wherein the average molecular weight is ≦50.

17. The ester-based polymer contains at least one of compounds represented by formula (CI) to (CIII), 【Chemistry 5】 In formula (CI), R ３１ , R ３２ and R ３３ each independently contains a hydrogen atom or a substituted or unsubstituted C1 to C8 alkyl group, R ３４ contains a substituted or unsubstituted C1 to C8 alkyl group or a substituted or unsubstituted C1 to C8 hydroxyalkyl group, 【Chemistry 6】 In formula (CII), R ３５ contains a substituted or unsubstituted C2-C6 methylene group, 【Chemistry 7】 In formula (CIII), R ３６ , R ３７ and R ３８ each independently contains a hydrogen atom or a substituted or unsubstituted C1 to C8 alkyl group, R ３９ contains a substituted or unsubstituted C1 to C8 alkyl group, The electrode sheet according to any one of claims 13 to 16, wherein the degree of polymerization n of the ester-based polymer is selected from any positive integer of 800 to 20,000.

18. The adsorbent polymer includes an aldehyde ketone polymer, and the sheet-like structure produced from the aldehyde ketone polymer is ｍ４ +20°C, a dynamic frequency scan test was performed to obtain a modulus of elasticity G'-loss modulus of elasticity G'' curve, and the slope K ３ is 0.8≦K ３ <∞, and T ｍ４ The electrode sheet according to any one of claims 1 to 17, wherein (°C) represents the melting temperature of the aldehyde ketone polymer.

19. 0.8≦K ３ 19. The electrode sheet according to claim 18, wherein the tensile strength is ≦100.

20. 0.8≦K ３ 20. The electrode sheet according to claim 19, wherein the tensile strength is ≦10.

21. The glass transition temperature T ｇ４ (°C) is -100≦T ｇ４ The electrode sheet according to any one of claims 18 to 20, wherein the average molecular weight is ≦50.

22. The aldehyde ketone polymer contains at least one of a compound represented by formula (DI) and a compound represented by formula (DII), 【Chemistry 8】 In formula (DI), R ４１ contains a single bond or a substituted or unsubstituted C1-C6 methylene group, and R ４２ contains a hydrogen atom or a substituted or unsubstituted C1-C6 alkyl group, 【Chemistry 9】 In formula (DII), R ４３ ~R ４６ each independently represents 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 an integer selected from 0 to 5, and at least one of r and s is selected from any positive integer; The electrode sheet according to any one of claims 18 to 21, wherein the degree of polymerization n of the aldehyde ketone polymer is selected from any positive integer of 500 to 15,000.

23. The molecular weight of the adsorbent polymer is 2.0 x 10 ５ g / mol~1.2×10 ６ The electrode sheet according to any one of claims 1 to 22, wherein the surface area is 100 μm or less.

24. A battery comprising the electrode sheet according to any one of claims 1 to 23.

25. 25. The battery of claim 24, wherein the electrode sheet is a positive electrode sheet and / or the electrode sheet is a negative electrode sheet.

26. 26. A power consuming device comprising a battery according to claim 24 or 25.

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