Electrode assembly, battery, battery module, battery pack, and electric device

Abstract

The application provides an electrode assembly, a battery, a battery module, a battery pack and a power utilization device. The electrode assembly comprises a first electrode sheet, a second electrode sheet opposite to the first electrode sheet in polarity, and a separator film arranged between the first electrode sheet and the second electrode sheet. The electrode assembly is obtained by winding the first electrode sheet, the second electrode sheet and the separator film. The separator film comprises a base film and a coating layer arranged on at least a part of the surface of the base film. The coating layer comprises a hydraulic inorganic material capable of being hardened by reacting with water. The application can solve the problem of collapse of the central hole of the electrode assembly and the battery, and improve the safety performance and cycle performance of the battery.

Description

Technical Field

[0001] This application belongs to the field of battery technology, specifically relating to an electrode assembly, a battery, a battery module, a battery pack, and an electrical device. Background Technology

[0002] Rechargeable batteries are widely used due to their advantages such as high energy density, long cycle life, reliable performance, no pollution, and no memory effect. In recent years, with the application and promotion of rechargeable batteries in various electronic products and new energy vehicles, their safety performance has received increasing attention. Traditional batteries include prismatic and cylindrical batteries. Compared with prismatic batteries, cylindrical batteries have advantages such as better structural stability, fewer components, and simpler manufacturing processes. Cylindrical batteries typically use wound electrode assemblies, which are formed by winding a positive electrode, a separator, and a negative electrode, with a central hole at the center. However, the central hole of cylindrical batteries is prone to collapse. Central hole collapse refers to the phenomenon where the central hole is partially or completely blocked during battery formation and cyclic charging / discharging. Central hole collapse makes venting difficult, increases safety risks, and thus seriously affects the battery's cycle performance. Summary of the Invention

[0003] The purpose of this application is to provide an electrode assembly, a battery, a battery module, a battery pack, and an electrical device, which aims to solve the problem of collapse of the center hole of the electrode assembly and battery, and improve the safety performance and cycle performance of the battery.

[0004] The first aspect of this application provides an electrode assembly including a first electrode, a second electrode with the opposite polarity to the first electrode, and a separator disposed between the first electrode and the second electrode. The electrode assembly is obtained by winding the first electrode, the second electrode, and the separator. The separator includes a base film and a coating disposed on at least a portion of the surface of the base film. The coating includes a hydraulic inorganic material that can harden by reacting with water.

[0005] This application provides a coating containing hydraulic inorganic materials on the surface of the base membrane. By utilizing the principle that hydraulic inorganic materials can harden by reacting with water, the strength of the separator can be significantly increased, making it less prone to deformation during battery formation and cyclic charging and discharging. This effectively suppresses the collapse of the central hole and dendrite growth, improves the safety performance of the battery, and extends the cycle life of the battery.

[0006] In any embodiment of this application, the hydraulic inorganic material includes at least one compound of Formula 1.

[0007] First oxide · a Second oxide · b Sulfate · c Halide Formula 1

[0008] Wherein, 0 < a ≤ 6, 0 ≤ b ≤ 4, 0 ≤ c ≤ 4, the first oxide represents CaO or BaO, the second oxide represents component 1, component 2, or a combination thereof, component 1 represents SiO2, Al2O3, Fe2O3, or a combination of two or more thereof, component 2 represents FeO, MgO, BaO, K2O, Na2O, TiO2, CuO, Cr2O3, P2O5, SO3, or a combination of two or more thereof, sulfate represents CaSO4, MgSO4, BaSO4, SrSO4, ZnSO4, Al2(SO4)3, FeSO4, Fe2(SO4)3, or a combination of two or more thereof, and halide represents CaCl2, CaF2, or a combination thereof.

[0009] The compound shown in Formula 1 above can effectively suppress central pore collapse and dendrite growth without significantly affecting the electrochemical performance of the battery.

[0010] Optionally, the weight ratio of component 1 to component 2 is (95-100):(0-5). When the weight ratio of component 1 to component 2 is within a suitable range, it is beneficial to adjust the compressive strength and heat of hydration of the coating, so that the coating can have appropriate compressive strength after reacting with water, while not releasing excessive heat after reacting with water.

[0011] In any embodiment of this application, the hydraulic inorganic material includes one or more compounds represented by formulas 1-1 to 1-8.

[0012] CaO·a1 SiO2·b sulfate·c halide (formula 1-1)

[0013] CaO·a2 Al2O3·b sulfate·c halide (formula 1-2)

[0014] CaO·a3Fe2O3·bSulfate·cHalide (Formula 1-3)

[0015] CaO·a4 Al2O3·a5 SiO2·b sulfate·c halide (formula 1-4)

[0016] CaO·a6 Al2O3·a7 Fe2O3·b sulfate·c halide (formula 1-5)

[0017] BaO·a8SiO2·bSulfate·cHalide (Formulas 1-6)

[0018] BaO·a9Al2O3·bSulfate·cHalide (Formula 1-7)

[0019] BaO·a10 Al2O3·a11 SiO2·b sulfate·c halide formula 1-8

[0020] Wherein, 0 < a1 ≤ 6, 0 < a2 ≤ 6, 0 < a3 ≤ 6, 0 < a4 < 6, 0 < a5 < 6, and 0 < a4 + a5 ≤ 6, 0 < a6 < 6, 0 < a7 < 6, and 0 < a6 + a7 ≤ 6, 0 < a8 ≤ 6, 0 < a9 ≤ 6, 0 < a10 < 6, 0 < a11 < 6, and 0 < a10 + a11 ≤ 6, 0 ≤ b ≤ 4, 0 ≤ c ≤ 4, sulfates represent CaSO4, MgSO4, BaSO4, SrSO4, ZnSO4, Al2(SO4)3, FeSO4, Fe2(SO4)3, or combinations of two or more thereof, and halides represent CaCl2, CaF2, or combinations thereof.

[0021] In any embodiment of this application, b = 0.

[0022] In any embodiment of this application, c = 0.

[0023] In any embodiment of this application, b = 0 and c = 0.

[0024] In any embodiment of this application, the hydraulic inorganic material includes 2CaO·SiO2, 3CaO·SiO2, CaO·Al2O3, CaO·2Al2O3, 3CaO·Al2O3, 6CaO·2Al2O3, 12CaO·7Al2O3, CaO·Fe2O3, 2CaO·Fe2O3, 2CaO·Al2O3·SiO2, CaO·Al2O3·2SiO2, 4CaO·Al2O3·Fe2O3, 6CaO·Al2O3·2Fe2O3, 3CaO·3Al2O3·CaSO4, 3CaO·3Al2O3·MgSO4, 3CaO·3Al2O3·BaSO4, and 3CaO·3Al2O3·SrSO4. 4. 3CaO·3Al2O3·ZnSO4, 3CaO·3Al2O3·Al2(SO4)3, 3CaO·3Al2O3·FeSO4, 3CaO·3Al2O3·Fe2(SO4)3, 2CaO·SiO2·CaSO4, 11CaO·7Al2O3·CaF2, 3CaO·3Al2O3· One or more of CaF2, CaO·3Al2O3·3CaF2, CaO·3Al2O3·4CaF2, 2BaO·SiO2, 3BaO·SiO2, BaO·Al2O3, 3BaO·Al2O3, BaO·6Al2O3, BaO·Al2O3·SiO2, BaO·Al2O3·2SiO2.

[0025] Optionally, the hydraulic inorganic material includes one or more of 2CaO·SiO2, 3CaO·SiO2, 3CaO·Al2O3, and 4CaO·Al2O3·Fe2O3.

[0026] In any embodiment of this application, the hydraulic inorganic material is a particle with a volumetric particle size Dv10 of 1 μm to 10 μm. Optionally, the hydraulic inorganic material is a particle with a volumetric particle size Dv10 of 3 μm to 5 μm. When the volumetric particle size Dv10 of the hydraulic inorganic material is within a suitable range, the coating consistency is higher.

[0027] In any embodiment of this application, the mass percentage of the hydraulic inorganic material is 95% to 100% based on the total mass of the coating. Optionally, the mass percentage of the hydraulic inorganic material is 97% to 100%.

[0028] In any embodiment of this application, the coating further includes additives, which include one or more of the following: water-reducing agents, gypsum, volcanic ash, fly ash, slag, quartz sand, limestone, and clay. The additives can regulate the compressive strength of the coating, regulate the setting rate of the coating in reaction with water, and reduce the heat of hydration.

[0029] In any embodiment of this application, the mass percentage of the additive is ≤5% based on the total mass of the coating. Optionally, the mass percentage of the additive is ≤3%.

[0030] In any embodiment of this application, the total thickness of the coating is 0.5 μm to 5 μm. Optionally, the total thickness of the coating is 0.5 μm to 2 μm. When the total thickness of the coating is within a suitable range, the coating can have appropriate compressive strength after reacting with water, while not releasing excessive heat after reacting with water.

[0031] In any embodiment of this application, the thickness of the base film is 5 μm to 12 μm. Optionally, the thickness of the base film is 6 μm to 7 μm.

[0032] In any embodiment of this application, the base membrane is selected from one or more of polyolefin porous membranes, nonwoven fabrics, and glass fibers.

[0033] In any embodiment of this application, the heat of hydration of the coating within 2 days of reacting with water is 300 J / g to 500 J / g. The coating exhibits appropriate heat release after reacting with water, which on the one hand increases the transport rate of active ions between the positive and negative electrodes of the battery, improving the battery's cycle performance and rate performance; on the other hand, it ensures that it does not affect other electrochemical properties of the battery.

[0034] In any embodiment of this application, the compressive strength of the coating after reacting and hardening with water is 2500 Pa to 20000 Pa. Optionally, the compressive strength of the coating after reacting and hardening with water is 2500 Pa to 10000 Pa. The coating exhibits high compressive strength after reacting with water; therefore, the separator is less prone to deformation during battery formation and cyclic charging and discharging, effectively suppressing central hole collapse and dendrite growth, improving battery safety performance, and extending battery cycle life.

[0035] In any embodiment of this application, the coating is located in a region from 0 cm to L cm from the starting end of the separator winding, where 10 ≤ L ≤ 20. The coating containing the hydraulic inorganic material is only disposed in a localized region at the starting end of the separator winding, thereby effectively suppressing central hole collapse and dendrite growth without significantly reducing the mass energy density of the battery.

[0036] The second aspect of this application provides a battery including an electrode assembly and an electrolyte, wherein the electrode assembly is the same as that of the battery according to the first aspect of this application, and the electrolyte includes an electrolyte salt and water.

[0037] Since the electrolyte of this application uses water as a solvent, when the coating containing hydraulic inorganic materials is immersed in the electrolyte, the hydraulic inorganic materials in the coating can react with the solvent water and fully harden the coating, thereby significantly increasing the strength of the separator. Therefore, the separator is not easily deformed during the battery formation process and during cyclic charging and discharging, effectively suppressing the collapse of the central hole and dendrite growth, improving the battery's safety performance, and extending the battery's cycle life.

[0038] In any embodiment of this application, the battery is a lithium-ion battery, a sodium-ion battery, a potassium-ion battery, a zinc-ion battery, a calcium-ion battery, a magnesium-ion battery, an aluminum-ion battery, or a hybrid-ion battery.

[0039] A third aspect of this application provides a battery module that includes the battery of the second aspect of this application.

[0040] The fourth aspect of this application provides a battery pack, which includes one of the battery of the second aspect of this application and the battery module of the third aspect.

[0041] The fifth aspect of this application provides an electrical device that includes at least one of the battery of the second aspect of this application, the battery module of the third aspect, and the battery pack of the fourth aspect.

[0042] The battery module, battery pack, and power device of this application include the battery provided in this application, and therefore have at least the same advantages as the battery. Attached Figure Description

[0043] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0044] Figure 1 This is a schematic diagram showing the cylindrical battery's central hole before and after collapse.

[0045] Figure 2 This is a schematic diagram of one embodiment of an electrical device that uses the battery of this application as a power source. Detailed Implementation

[0046] The following detailed description, with appropriate reference to the accompanying drawings, specifically discloses embodiments of the electrode assembly, battery, battery module, battery pack, and power-consuming device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0047] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0048] Unless otherwise specified, all embodiments and optional embodiments of this application may be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of this application.

[0049] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions, and such technical solutions shall be deemed to be included in the disclosure of this application.

[0050] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0051] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0052] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0053] Figure 1 This is a schematic diagram showing the cylindrical battery's central hole before and after collapse. Figure 1As shown, cylindrical batteries have a central hole at the center, which is prone to collapse during battery formation and cyclic charging / discharging. Collapse of the central hole increases the internal gaps within the battery (e.g., the gap between the positive and negative electrodes), making it easier for dendrites to grow, affecting battery safety performance and reducing cycle life. The collapse of the central hole is influenced by factors such as the gas generation rate during battery formation, electrode coating weight, current collector thickness, and electrode rebound rate. Generally, a greater electrode coating weight and a higher gas generation rate during battery formation make the central hole more prone to collapse; a thinner current collector thickness and a higher electrode rebound rate also make the central hole more prone to collapse. Therefore, increasing the load-bearing capacity of the electrodes and separator in the local area of ​​the central hole can prevent deformation of the central hole and thus suppress its collapse. Existing technologies can increase the hardness of the separator to some extent by applying a ceramic coating to the surface of the separator base film, but the hardness of the separator is still relatively low and cannot effectively suppress the collapse of the central hole.

[0054] Based on the above problems, the inventors improved the structure of the separator and proposed an electrode assembly and battery that can effectively suppress the collapse of the central hole.

[0055] Electrode components and batteries

[0056] The battery of this application includes a casing, electrode assembly, end caps, and electrolyte. The electrode assembly is disposed within the casing, and the end caps are disposed on the casing. The electrolyte is immersed in the electrode assembly and serves to conduct active ions between the positive and negative electrodes. The electrolyte includes an electrolyte salt and water; the type of electrolyte salt is not specifically limited and can be selected according to actual needs. The material of the casing is not specifically limited, and can be, for example, a hard plastic casing, an aluminum casing, a steel casing, etc.

[0057] It should be noted that the battery in this application can be a lithium-ion battery, sodium-ion battery, potassium-ion battery, zinc-ion battery, calcium-ion battery, magnesium-ion battery, aluminum-ion battery, or a hybrid-ion battery. In this application, the term "hybrid-ion battery" refers to a battery in which there are two or more active ion insertion / extraction reactions between the positive and negative electrodes. Typically, the electrolyte of a hybrid-ion battery contains two or more active ions, such as two or more of lithium ions, sodium ions, potassium ions, zinc ions, calcium ions, magnesium ions, and aluminum ions. As examples, hybrid-ion batteries may include lithium-sodium hybrid-ion batteries, sodium-zinc hybrid-ion batteries, sodium-potassium hybrid-ion batteries, etc.

[0058] The electrode assembly of this application includes a first electrode, a second electrode with the opposite polarity to the first electrode, and a separator disposed between the first electrode and the second electrode. The electrode assembly is obtained by winding the first electrode, the second electrode, and the separator. The separator includes a base film and a coating disposed on at least a portion of the surface of the base film. The coating includes a hydraulic inorganic material that can harden by reacting with water.

[0059] The inventors unexpectedly discovered that by setting a coating containing hydraulic inorganic materials on the surface of the base film, and utilizing the principle that hydraulic inorganic materials can harden by reacting with water, the strength of the separator can be significantly increased, making it less prone to deformation during battery formation and cyclic charging and discharging. This effectively inhibits the collapse of the central hole and dendrite growth, improves the safety performance of the battery, and extends the cycle life of the battery.

[0060] Since the electrolyte of this application uses water as a solvent, when the coating containing hydraulic inorganic materials is immersed in the electrolyte, the hydraulic inorganic materials in the coating can react with the solvent water and fully harden the coating, thereby significantly increasing the strength of the separator. Therefore, the separator is not easily deformed during the battery formation process and during cyclic charging and discharging, effectively suppressing the collapse of the central hole and dendrite growth, improving the battery's safety performance, and extending the battery's cycle life.

[0061] The electrode assembly of this application is a wound electrode assembly, and the shape of the electrode assembly end face is not specifically limited and can be selected according to actual needs. For example, the electrode assembly end face can be a regular shape such as a circle, ellipse, or rectangle, or it can be an irregular shape.

[0062] In some embodiments, the hydraulic inorganic material comprises at least one compound of Formula 1.

[0063] First oxide · a Second oxide · b Sulfate · c Halide Formula 1

[0064] In Equation 1, 0 < a ≤ 6, 0 ≤ b ≤ 4, 0 ≤ c ≤ 4, the first oxide represents CaO or BaO, the second oxide represents component 1, component 2, or a combination thereof, component 1 represents SiO2, Al2O3, Fe2O3, or a combination of two or more thereof, component 2 represents FeO, MgO, BaO, K2O, Na2O, TiO2, CuO, Cr2O3, P2O5, SO3, or a combination of two or more thereof, sulfate represents CaSO4, MgSO4, BaSO4, SrSO4, ZnSO4, Al2(SO4)3, FeSO4, Fe2(SO4)3, or a combination of two or more thereof, and halide represents CaCl2, CaF2, or a combination thereof.

[0065] The reaction products of the compound shown in Formula 1 with water include one or more of the following: gel, hydrate, Ca(OH)2, etc. Furthermore, the compound shown in Formula 1 exhibits appropriate compressive strength after reacting with water, and does not release excessive heat. Therefore, the compound shown in Formula 1 can effectively suppress central pore collapse and dendrite growth without significantly affecting the electrochemical performance of the battery.

[0066] In some embodiments, the weight ratio of component 1 to component 2 is (95-100):(0-5). When the weight ratio of component 1 to component 2 is within a suitable range, it is beneficial to adjust the compressive strength and heat of hydration of the coating, so that the coating can have appropriate compressive strength after reacting with water, while not releasing excessive heat after reacting with water.

[0067] In some embodiments, the second oxide represents only component 1.

[0068] In some embodiments, b = 0.

[0069] In some embodiments, 0 < b ≤ 4. A moderate sulfate content is beneficial for adjusting the compressive strength and heat of hydration of the coating, ensuring that the coating has appropriate compressive strength after reacting with water, while not releasing excessive heat.

[0070] In some embodiments, c = 0.

[0071] In some embodiments, 0 < c ≤ 4. A moderate content of halide is beneficial for adjusting the compressive strength and heat of hydration of the coating, ensuring that the coating has appropriate compressive strength after reacting with water, while not releasing excessive heat.

[0072] In some embodiments, b = 0 and c = 0.

[0073] The compound shown in Formula 1 can be prepared according to conventional methods in the art, such as high-temperature solid-state reaction. An exemplary preparation method is as follows: a Ca or Ba source, an M1 element precursor, optional SO3, and optional halogen precursor are mixed uniformly in a certain molar ratio, and then calcined at high temperature to obtain the compound shown in Formula 1. M1 is selected from one or more of Si, Al, Fe, K, Na, Mg, Ba, Ti, Cu, Cr, Sr, Zn, etc. Optionally, the calcination temperature is 800℃~1600℃.

[0074] As examples, Ca sources include, but are not limited to, one or more of CaO, CaCO3, and Ca(OH)2. As examples, Ba sources include, but are not limited to, one or more of BaO, BaCO3, and Ba(OH)2. As examples, M1 element precursors include, but are not limited to, one or more of oxides, hydroxides, sulfuric acid compounds, hydrochloric acid compounds, nitric acid compounds, carbonate compounds, and acetic acid compounds of M1 element. For example, M1 element precursors are one or more of SiO2, Al(OH)3, Al2O3, Fe2O3, FeO, K2O, Na2O, MgO, BaO, TiO2, CuO, Cr2O3, SrO, and ZnO. As examples, halogen precursors include, but are not limited to, one or more of ammonium fluoride, hydrogen fluoride, ammonium chloride, and hydrogen chloride.

[0075] In some embodiments, the hydraulic inorganic material includes compounds of formula 1-1, and sulfates and halides as defined herein.

[0076] CaO·a1 SiO2·b sulfate·c halide (formula 1-1)

[0077] In Equation 1-1, 0 < a1 ≤ 6, 0 ≤ b ≤ 4, and 0 ≤ c ≤ 4.

[0078] Optionally, 0 < a1 ≤ 3, b = 0, c = 0.

[0079] Optionally, 0 < a1 ≤ 3, 0 < b ≤ 4, and c = 0.

[0080] Optionally, 0 < a1 ≤ 3, b = 0, 0 < c ≤ 4.

[0081] In some embodiments, the hydraulic inorganic material includes compounds of formulas 1-2, and sulfates and halides as defined herein.

[0082] CaO·a2 Al2O3·b sulfate·c halide (formula 1-2)

[0083] In Equation 1-2, 0 < a2 ≤ 6, 0 ≤ b ≤ 4, and 0 ≤ c ≤ 4.

[0084] Alternatively, 0 < a² ≤ 3, b = 0, c = 0.

[0085] Optionally, 0 < a² ≤ 3, 0 < b ≤ 4, and c = 0.

[0086] Optionally, 0 < a² ≤ 3, b = 0, and 0 < c ≤ 4.

[0087] In some embodiments, the hydraulic inorganic material includes compounds of formulas 1-3, and sulfates and halides as defined herein.

[0088] CaO·a3Fe2O3·bSulfate·cHalide (Formula 1-3)

[0089] In Equation 1-3, 0 < a3 ≤ 6, 0 ≤ b ≤ 4, and 0 ≤ c ≤ 4.

[0090] Alternatively, 0 < a3 ≤ 3, b = 0, c = 0.

[0091] Alternatively, 0 < a3 ≤ 3, 0 < b ≤ 4, and c = 0.

[0092] Alternatively, 0 < a3 ≤ 3, b = 0, 0 < c ≤ 4.

[0093] In some embodiments, the hydraulic inorganic material includes compounds of formulas 1-4, and sulfates and halides as defined herein.

[0094] CaO·a4 Al2O3·a5 SiO2·b sulfate·c halide (formula 1-4)

[0095] In equation 1-4, 0 < a4 < 6, 0 < a5 < 6, and 0 < a4 + a5 ≤ 6, 0 ≤ b ≤ 4, and 0 ≤ c ≤ 4.

[0096] Alternatively, 0 < a4 ≤ 2, 0 < a5 ≤ 2, and 0 < a4 + a5 ≤ 3, b = 0, c = 0.

[0097] Optionally, 0 < a4 ≤ 2, 0 < a5 ≤ 2, and 0 < a4 + a5 ≤ 3, 0 < b ≤ 4, and c = 0.

[0098] Optionally, 0 < a4 ≤ 2, 0 < a5 ≤ 2, and 0 < a4 + a5 ≤ 3, b = 0, and 0 < c ≤ 4.

[0099] In some embodiments, the hydraulic inorganic material includes compounds of formulas 1-5, and sulfates and halides as defined herein.

[0100] CaO·a6 Al2O3·a7 Fe2O3·b sulfate·c halide (formula 1-5)

[0101] In equations 1-5, 0 < a6 < 6, 0 < a7 < 6, and 0 < a6 + a7 ≤ 6, 0 ≤ b ≤ 4, and 0 ≤ c ≤ 4.

[0102] Alternatively, 0 < a6 ≤ 2, 0 < a7 ≤ 2, and 0 < a6 + a7 ≤ 3, b = 0, c = 0.

[0103] Optionally, 0 < a6 ≤ 2, 0 < a7 ≤ 2, and 0 < a6 + a7 ≤ 3, 0 < b ≤ 4, and c = 0.

[0104] Optionally, 0 < a6 ≤ 2, 0 < a7 ≤ 2, and 0 < a6 + a7 ≤ 3, b = 0, and 0 < c ≤ 4.

[0105] In some embodiments, the hydraulic inorganic material includes compounds of formulas 1-6, and sulfates and halides as defined herein.

[0106] BaO·a8SiO2·bSulfate·cHalide (Formulas 1-6)

[0107] In Equation 1-6, 0 < a8 ≤ 6, 0 ≤ b ≤ 4, and 0 ≤ c ≤ 4.

[0108] Optionally, 0 < a8 ≤ 3, b = 0, c = 0.

[0109] Optionally, 0 < a8 ≤ 3, 0 < b ≤ 4, and c = 0.

[0110] Alternatively, 0 < a8 ≤ 3, b = 0, 0 < c ≤ 4.

[0111] In some embodiments, the hydraulic inorganic material includes compounds of formulas 1-7, and sulfates and halides as defined herein.

[0112] BaO·a9Al2O3·bSulfate·cHalide (Formula 1-7)

[0113] In Equation 1-7, 0 < a9 ≤ 6, 0 ≤ b ≤ 4, and 0 ≤ c ≤ 4.

[0114] Optionally, 0 < a9 ≤ 6, b = 0, c = 0.

[0115] Optionally, 0 < a9 ≤ 6, 0 < b ≤ 4, and c = 0.

[0116] Alternatively, 0 < a9 ≤ 6, b = 0, 0 < c ≤ 4.

[0117] In some embodiments, the hydraulic inorganic material includes compounds of formulas 1-8, and sulfates and halides as defined herein.

[0118] BaO·a10 Al2O3·a11 SiO2·b sulfate·c halide formula 1-8

[0119] In equation 1-8, 0 < a10 < 6, 0 < a11 < 6, and 0 < a10 + a11 ≤ 6, 0 ≤ b ≤ 4, and 0 ≤ c ≤ 4.

[0120] Alternatively, 0 < a10 ≤ 2, 0 < a11 ≤ 2, and 0 < a10 + a11 ≤ 3, b = 0, c = 0.

[0121] Optionally, 0 < a10 ≤ 2, 0 < a11 ≤ 2, and 0 < a10 + a11 ≤ 3, 0 < b ≤ 4, and c = 0.

[0122] Optionally, 0 < a10 ≤ 2, 0 < a11 ≤ 2, and 0 < a10 + a11 ≤ 3, b = 0, and 0 < c ≤ 4.

[0123] In some embodiments, the hydraulic inorganic material includes two or more compounds of formulas 1-1 to 1-8. In this case, it is beneficial to adjust the compressive strength and heat of hydration of the coating so that the coating can have appropriate compressive strength after reacting with water, while not releasing excessive heat after reacting with water.

[0124] In some embodiments, as an example, the hydraulic inorganic material includes 2CaO·SiO2, 3CaO·SiO2, CaO·Al2O3, CaO·2Al2O3, 3CaO·Al2O3, 6CaO·2Al2O3, 12CaO·7Al2O3, CaO·Fe2O3, 2CaO·Fe2O3, 2CaO·Al2O3·SiO2, CaO·Al2O3·2SiO2, 4CaO·Al2O3·Fe2O3, 6CaO·Al2O3·2Fe2O3, 3CaO·3Al2O3·CaSO4, 3CaO·3Al2O3·MgSO4, 3CaO·3Al2O3·BaSO4, and 3CaO·3Al2O3·SrS O4, 3CaO·3Al2O3·ZnSO4, 3CaO·3Al2O3·Al2(SO4)3, 3CaO·3Al2O3·FeSO4, 3CaO·3Al2O3·Fe2(SO4)3, 2CaO·SiO2·CaSO4, 11CaO·7Al2O3·CaF2, 3CaO·3Al2O3· One or more of CaF2, CaO·3Al2O3·3CaF2, CaO·3Al2O3·4CaF2, 2BaO·SiO2, 3BaO·SiO2, BaO·Al2O3, 3BaO·Al2O3, BaO·6Al2O3, BaO·Al2O3·SiO2, BaO·Al2O3·2SiO2.

[0125] Optionally, the hydraulic inorganic material includes one or more of 2CaO·SiO2, 3CaO·SiO2, 3CaO·Al2O3, and 4CaO·Al2O3·Fe2O3.

[0126] In some embodiments, the hydraulic inorganic material is a particle with a volumetric particle size Dv10 of 1 μm to 10 μm. For example, the volumetric particle size Dv10 of the hydraulic inorganic material particles is within the range of 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, or any of the above values. Optionally, the hydraulic inorganic material is a particle with a volumetric particle size Dv10 of 3 μm to 5 μm. When the volumetric particle size Dv10 of the hydraulic inorganic material particles is within a suitable range, the coating exhibits higher consistency.

[0127] In some embodiments, the hydraulic inorganic material comprises 95% to 100% by mass, based on the total mass of the coating. Optionally, the hydraulic inorganic material comprises 97% to 100% by mass.

[0128] In some embodiments, the coating further includes additives that can regulate the compressive strength of the coating, regulate the setting rate of the coating in reaction with water, and reduce the heat of hydration. As examples, the additives include, but are not limited to, one or more of water-reducing admixtures, gypsum, volcanic ash, fly ash, slag, quartz sand, limestone, and clay. Among these, gypsum includes one or more of natural dihydrate gypsum, anhydrite, hemihydrate gypsum, phosphogypsum, and desulfurized gypsum. The type of additive is not specifically limited and can be selected according to actual needs; for example, the water-reducing agent can be a polycarboxylate superplasticizer. These additives can be used alone or in combination. Based on the total mass of the coating, the mass percentage of the additives is ≤5%. For example, the mass percentage of the additives is ≤4.5%, ≤4%, ≤3.5%, ≤3%, ≤2.5%, ≤2%, ≤1.5%, ≤1%, ≤0.5%, or 0%.

[0129] In some embodiments, the thickness of the base film is 5 μm to 12 μm. Optionally, the thickness of the base film is 6 μm to 7 μm. When the thickness of the base film is within a suitable range, the separator can have sufficient compressive strength while also having high ionic conductivity.

[0130] In some embodiments, the porosity of the base membrane is 30% to 50%. Optionally, the porosity of the base membrane is 35% to 50%. When the porosity of the base membrane is within a suitable range, the separator can have sufficient compressive strength while also having high ionic conductivity.

[0131] In some embodiments, the type of base membrane is not particularly limited, and any well-known porous membrane with good chemical and mechanical stability can be selected. Optionally, the base membrane is selected from one or more of polyolefin porous membranes, nonwoven fabrics, and glass fibers. The base membrane can be a single-layer membrane or a multilayer composite membrane. When the base membrane is a multilayer composite membrane, the materials of each layer may be the same or different. As an example, the material of the base membrane can be selected from one or more of polyethylene, polypropylene, polyimide, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, and polyethylene terephthalate.

[0132] The base film has two surfaces opposite each other in its thickness direction, and the coating is disposed on either or both of the two surfaces of the base film.

[0133] In some embodiments, the total thickness of the coating is 0.5 μm to 5 μm. In this application, the term "total coating thickness" refers to the sum of the thicknesses of the coatings disposed on both surfaces of the base film. When the coating is disposed on either of the two surfaces of the base film, the thickness of the coating is the total coating thickness; when the coating is disposed on both of the two surfaces of the base film, the sum of the thicknesses of the coatings is the total coating thickness.

[0134] For example, the total thickness of the coating is within the range of 0.5 μm, 1.0 μm, 1.5 μm, 2.0 μm, 2.5 μm, 3.0 μm, 3.5 μm, 4.0 μm, 4.5 μm, 5.0 μm, or any of the values ​​above. Optionally, the total thickness of the coating is between 0.5 μm and 2 μm. When the total thickness of the coating is within a suitable range, the coating can exhibit appropriate compressive strength after reacting with water, while not releasing excessive heat after reacting with water.

[0135] In some embodiments, the heat of hydration of the coating reacting with water within 2 days is 300 J / g to 500 J / g. For example, the heat of hydration of the coating reacting with water within 2 days is a range consisting of 300 J / g, 310 J / g, 320 J / g, 330 J / g, 340 J / g, 350 J / g, 360 J / g, 370 J / g, 380 J / g, 390 J / g, 400 J / g, 410 J / g, 420 J / g, 430 J / g, 440 J / g, 450 J / g, 460 J / g, 470 J / g, 480 J / g, 490 J / g, 500 J / g, or any of the above values. By adjusting the composition and thickness of the coating, the coating can be made to have appropriate heat release after reacting with water. On the one hand, this can increase the transport speed of active ions between the positive and negative electrodes of the battery, thereby improving the cycle performance and rate performance of the battery. On the other hand, it can ensure that it does not affect other electrochemical performance of the battery.

[0136] In some embodiments, the compressive strength of the coating after reacting and hardening with water is 2500 Pa to 20000 Pa. For example, the compressive strength of the coating after reacting and hardening with water is within the range of 2500 Pa, 3000 Pa, 4000 Pa, 5000 Pa, 6000 Pa, 7000 Pa, 8000 Pa, 9000 Pa, 10000 Pa, 11000 Pa, 12000 Pa, 13000 Pa, 14000 Pa, 15000 Pa, 16000 Pa, 17000 Pa, 18000 Pa, 19000 Pa, 20000 Pa, or any of the above values. Optionally, the compressive strength of the coating after reacting and hardening with water is 2500 Pa to 18000 Pa, 2500 Pa to 16000 Pa, 2500 Pa to 14000 Pa, 2500 Pa to 12000 Pa, 2500 Pa to 10000 Pa, 2500 Pa to 9000 Pa, 2500 Pa to 8000 Pa, 2500 Pa to 7000 Pa, 2500 Pa to 6000 Pa, or 2500 Pa to 5000 Pa. By adjusting the composition and thickness of the coating, the coating can have a high compressive strength after reacting with water, thus making the separator less prone to deformation during battery formation and cyclic charging and discharging. This effectively suppresses central hole collapse and dendrite growth, improves battery safety performance, and extends battery cycle life.

[0137] Heat of hydration is a well-known concept in the art and can be determined using instruments and methods known in the art. For example, the heat of hydration of a coating is determined using a TAM Air thermally active microcalorimeter (from TA Instruments, USA). An exemplary test method is as follows: A freshly prepared release liner is taken for testing. A sample of the coating is taken from a randomly selected area of ​​the release liner (e.g., by scraping powder with a blade). The mass of all collected samples is weighed. All collected samples are placed into an ampoule. A measured amount of water is drawn from the syringe on an electric stirrer. The electric stirrer is then inserted into the ampoule. The electric stirrer and the ampoule are placed together at the measurement position of the microcalorimeter. Finally, the water from the syringe is injected into the ampoule, and stirring and recording are started to obtain the total heat release during the test period. The test period is 48 hours, and the test temperature is room temperature.

[0138] Compressive strength is a term known in the art and can be measured using instruments and methods known in the art. During testing, the separator sample can be a freshly prepared separator or obtained from the battery.

[0139] When testing a freshly prepared release liner, an exemplary testing method is as follows: Take a freshly prepared single-sided coated release liner sample for testing. If it is a double-sided coated release liner, the coating on one side can be wiped off first. Place the release liner in deionized water to allow the coating to fully react with the water and harden. Remove the release liner from the deionized water, allow it to dry completely, and then place it in a compressive strength tester (e.g., a YN-200-400 microcomputer compressive strength tester) for testing to obtain the failure load when the release liner is damaged. Optionally, the loading rate is 0.4 MPa / s to 0.6 MPa / s.

[0140] When removing the separator from the battery, an exemplary testing method is as follows: After fully loading the battery, remove the separator and test the fully hardened area at the beginning of the winding. If the separator is double-coated, wipe off the coating on one side first. Place the separator in an oven to dry thoroughly (e.g., 45°C, 30 min) to remove excess electrolyte, and then place it in a compressive strength tester (e.g., a YN-200-400 microcomputer compressive strength tester) to obtain the breaking load when the separator is damaged. Optionally, the loading rate is 0.4 MPa / s to 0.6 MPa / s.

[0141] The compressive strength of the coating after it has hardened by the reaction with water is calculated using the formula p = P / A, where p represents the compressive strength of the sample, P represents the failure load of the sample, and A represents the area of ​​the sample.

[0142] In some embodiments, the coating is located in a region from 0 cm to L cm from the starting end of the separator winding, where 10 ≤ L ≤ 20. The coating containing the hydraulic inorganic material is only disposed in a localized region at the starting end of the separator winding, thereby effectively suppressing central hole collapse and dendrite growth without significantly reducing the battery's mass energy density. Therefore, the electrode assembly of this application can simultaneously possess high safety performance and high energy density.

[0143] The separator membrane can be prepared according to conventional methods in the art. An exemplary preparation method is as follows: a hydraulic inorganic material and optional additives are dissolved in an organic solvent and thoroughly stirred to form a uniform coating slurry; the coating slurry is coated onto the surface of a base membrane and dried to obtain the separator membrane. The type of organic solvent is not specifically limited and can be selected according to actual needs. For example, the organic solvent is selected from dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, etc.

[0144] In some embodiments, the pH of the electrolyte is 5 to 9. Optionally, the pH of the electrolyte is 7.

[0145] In some embodiments, the concentration of the electrolyte salt may be 0.5 mol / L to 2.0 mol / L. Optionally, the concentration of the electrolyte salt is 1.0 mol / L.

[0146] In some embodiments, as examples, the electrolyte salt includes, but is not limited to, one or more of Li2SO4, LiNO3, LiCl, LiCF3SO3, Na2SO4, NaNO3, NaCl, NaCF3SO3, K2SO4, KNO3, KCl, KCF3SO3, ZnSO4, Zn(NO3)2, ZnCl2, Zn(CF3SO3)2, Ca(NO3)2, CaCl2, Ca(CF3SO3)2, MgSO4, Mg(NO3)2, MgCl2, Mg(CF3SO3)2, Sr(NO3)2, SrCl2, Sr(CF3SO3)2, Ba(NO3)2, BaCl2, Ba(CF3SO3)2, Al2(SO4)3, Al(NO3)3, AlCl3, and Al(CF3SO3)3.

[0147] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature performance, additives that improve battery low-temperature performance, etc.

[0148] In some embodiments, the first electrode is a positive electrode and the second electrode is a negative electrode.

[0149] The positive electrode may include a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector. As an example, the positive current collector has two surfaces opposite each other in its thickness direction, and the positive electrode film layer is disposed on either or both of the two surfaces of the positive current collector.

[0150] The positive electrode film typically comprises a positive electrode active material, an optional conductive agent, and an optional binder. The positive electrode film is usually formed by coating a positive electrode slurry onto a positive electrode current collector, followed by drying and cold pressing. The positive electrode slurry is typically formed by dispersing the positive electrode active material, an optional conductive agent, an optional binder, and any other components in a solvent and stirring until homogeneous. The solvent can be deionized water, N-methylpyrrolidone (NMP), but is not limited to these. As examples, binders used for the positive electrode film include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resins, styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS). As an example, the conductive agents used for the positive electrode film include one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0151] The positive electrode current collector can be a metal foil or a composite current collector. As an example of a metal foil, the positive electrode current collector can be aluminum foil. The composite current collector may include a polymer material substrate and a metal material layer formed on at least one surface of the polymer material substrate. As an example, the metal material can be selected from one or more of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. As an example, the polymer material substrate can be selected from polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.

[0152] The negative electrode includes a negative current collector and a negative electrode film disposed on at least one surface of the negative current collector. As an example, the negative current collector has two surfaces opposite each other in its thickness direction, and the negative electrode film is disposed on either or both of the two surfaces of the negative current collector.

[0153] The negative electrode film typically comprises a negative electrode active material, an optional binder, an optional conductive agent, and other optional additives. The negative electrode film is usually formed by coating a negative electrode slurry onto a negative electrode current collector, followed by drying and cold pressing. The negative electrode slurry is typically formed by dispersing the negative electrode active material, an optional conductive agent, an optional binder, and any other components in a solvent and stirring until homogeneous. The solvent can be deionized water, N-methylpyrrolidone (NMP), but is not limited to these. As examples, binders used for the negative electrode film include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resins, styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS). As examples, conductive agents used in the negative electrode film include one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. Other additives used in the negative electrode film include thickeners, such as sodium carboxymethyl cellulose (CMC-Na).

[0154] The negative electrode current collector can be a metal foil or a composite current collector. As an example of a metal foil, copper foil can be used. The composite current collector may include a polymer material substrate and a metal material layer formed on at least one surface of the polymer material substrate. As an example, the metal material may be selected from one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. As an example, the polymer material substrate may be selected from polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.

[0155] The positive and negative active materials may be materials known in the art for use in lithium-ion batteries, sodium-ion batteries, potassium-ion batteries, zinc-ion batteries, calcium-ion batteries, magnesium-ion batteries, aluminum-ion batteries, or hybrid-ion batteries.

[0156] The positive electrode active material is selected from materials whose active ion (e.g., lithium ion, sodium ion, potassium ion, zinc ion, calcium ion, magnesium ion, aluminum ion, etc.) insertion potential is lower than the oxygen evolution potential of water. The negative electrode active material is selected from materials whose active ion (e.g., lithium ion, sodium ion, potassium ion, zinc ion, calcium ion, magnesium ion, aluminum ion, etc.) insertion potential is higher than the oxygen evolution potential of water.

[0157] As examples, positive electrode active materials include one or more of transition metal oxide materials, polyanionic materials (e.g., olivine structure, NASICON structure, Maricite structure, pyrophosphate, fluorophosphate, sulfate, etc.), Prussian blue materials, organic polymer materials, and their respective modified compounds. Examples of transition metal oxide materials may include, but are not limited to, Na. x MO2 (where M is a transition metal, preferably one or more of Mn, Fe, Ni, Co, V, Cu, and Cr, 0 < x ≤ 1), manganese-based oxides, vanadium-based oxides, and their respective modified compounds, one or more. Examples of organic polymer materials include, but are not limited to, poly2,2,6,6-tetramethylpiperidinoxy-4-vinyl ether (PTVE). This application is not limited to these materials, and other conventionally known materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more.

[0158] Optionally, the modified compounds of the above-mentioned positive electrode active materials can be used to modify the positive electrode active materials by doping, surface coating, or doping and surface coating at the same time.

[0159] As examples, negative electrode active materials include one or more of artificial graphite, natural graphite, soft carbon, hard carbon, activated carbon, transition metal oxides, and organic polymer materials. Examples of organic polymer materials may include, but are not limited to, polyimide (PI) and quinones, such as poly(2-vinylanthraquinone) (PVAQ). However, this application is not limited to these materials, and other conventionally known materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0160] Battery modules and battery packs

[0161] In some embodiments of this application, the battery according to this application can be assembled into a battery module, and the number of batteries contained in the battery module can be multiple, the specific number of which can be adjusted according to the application and capacity of the battery module.

[0162] In a battery module, multiple batteries can be arranged sequentially along the length of the module. Of course, they can also be arranged in any other manner. Furthermore, these batteries can be secured using fasteners.

[0163] Optionally, the battery module may also include a housing with a receiving space in which multiple batteries are housed.

[0164] In some embodiments of this application, the battery modules described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0165] Optionally, the battery pack may also include a battery box and multiple battery modules disposed within the battery box. The battery box includes an upper body and a lower body, the upper body covering the lower body and forming a closed space for accommodating the battery modules. The multiple battery modules can be arranged in any manner within the battery box.

[0166] Electrical appliances

[0167] Embodiments of this application also provide an electrical device, which includes at least one of the battery, battery module, and battery pack described in this application. The battery, battery module, or battery pack can be used as a power source for the electrical device or as an energy storage unit for the electrical device. The electrical device may be, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0168] The electrical device can be equipped with a battery, battery module, or battery pack according to its usage requirements.

[0169] Figure 2 This is a schematic diagram of an example electrical device. The device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the device's requirements for high power and high energy density, a battery pack or battery module can be used.

[0170] Another example of an electrical device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can use batteries as their power source.

[0171] Example

[0172] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0173] Example 1

[0174] Preparation of positive electrode sheet

[0175] Na, the positive electrode active material 0.44MnO2, conductive agent carbon black, and binder PVA are mixed thoroughly in an appropriate amount of deionized water at a mass ratio of 96:2:2 to form a uniform positive electrode slurry. The positive electrode slurry is coated on both surfaces of the positive electrode current collector aluminum foil, and after drying and cold pressing, the positive electrode sheet is obtained.

[0176] Preparation of negative electrode sheet

[0177] The negative electrode active material hard carbon, conductive agent carbon black, and binder PVA are mixed in an appropriate amount of deionized water at a mass ratio of 95:2.5:2.5 to form a uniform negative electrode slurry. The negative electrode slurry is coated on both surfaces of the negative electrode current collector copper foil, and after drying and cold pressing, the negative electrode sheet is obtained.

[0178] Preparation of the separating membrane

[0179] A coating slurry was prepared by dissolving 3CaO·SiO2 (Dv10 = 4.7 μm) in dimethyl carbonate. A gravure roller was immersed in the slurry, and as the roller rotated, the slurry filled the pits on its surface. The slurry on the roller's surface was scraped off with a doctor blade, leaving only the slurry in the pits. When the roller reached the contact position with the base film (a 7 μm thick porous polyethylene film), the slurry in the pits was transferred to one surface of the base film under the action of a pressure roller. The slurry coating length was approximately 10 μm, and the coating thickness was 5 μm.

[0180] Preparation of electrolyte

[0181] Na2SO4 was uniformly dissolved in deionized water to obtain an electrolyte with pH=7 and a Na2SO4 concentration of 1 mol / L.

[0182] Battery manufacturing

[0183] The positive electrode sheet, separator, and negative electrode sheet prepared above are stacked and wound in sequence to obtain a wound electrode assembly. The wound electrode assembly is placed in an aluminum shell and then subjected to processes such as end cap welding, liquid injection, encapsulation, standing, and formation to obtain a cylindrical battery.

[0184] Examples 2-19 and Comparative Examples 1-2

[0185] The battery preparation method is similar to that in Example 1, except that the preparation parameters of the separator were adjusted, as detailed in Table 1.

[0186] Table 1

[0187]

[0188]

[0189] Performance testing section

[0190] (1) Coating hydration heat test

[0191] Freshly prepared isolation membranes were used for testing. A sample of the coating was scraped from a randomly selected area of ​​the membrane, and the mass of all collected samples was weighed. All collected samples were placed into ampoules, and a measured amount of water was drawn using a syringe attached to an electric stirrer. The electric stirrer was then inserted into the ampoule, and the stirrer and ampoule were placed together at the measurement position of the microcalorimeter. Finally, the water from the syringe was injected into the ampoule, and stirring and recording were initiated to obtain the total heat release during the test period. The heat of hydration of the coating (J / g) = total heat release (J) / sample mass (g). The test period was 48 hours, the test temperature was room temperature, and the microcalorimeter used was a TAM Air eight-channel microcalorimeter.

[0192] (2) Coating compressive strength test

[0193] After fully discharging the battery, remove the separator and test the fully hardened area at the beginning of the winding. Dry the separator in a 45℃ oven for 30 minutes to remove excess electrolyte. Then, place the separator at the center of the lower platen of a YN-200-400 microcomputer compressive strength tester. Start the instrument and apply a uniform and continuous load until the separator is damaged, recording the failure load at this point. The loading rate is 0.4 MPa / s to 0.6 MPa / s.

[0194] The compressive strength of the coating is calculated using the formula p = P / A, where p represents the compressive strength of the sample, P represents the failure load of the sample, and A represents the area of ​​the sample.

[0195] (3) Battery internal temperature test

[0196] Temperature changes inside the battery are monitored by attaching temperature-sensing wires to the outer surface of the wound electrode assembly, and the highest internal temperature is recorded. The temperature detection instrument is a KSD301 temperature sensor.

[0197] (4) Ratio Performance Test

[0198] At 25°C, the battery was charged at a constant current of 1 / 3C to 2.0V, and then charged at a constant voltage until the current was 0.05C. After the battery was left to stand for 5 minutes, it was discharged at a constant current of 4C to 0.5V, and the discharge capacity at the 4C rate was recorded.

[0199] (5) Cyclic performance test

[0200] At 25℃, the battery was charged at a constant current of 1 / 3C to 2.0V, and then charged at a constant voltage until the current reached 0.05C. At this point, the battery was fully charged, and the charging capacity was recorded, which is the first charge capacity. After letting the battery rest for 5 minutes, it was discharged at a constant current of 4C to 0.5V. This completes one charge-discharge cycle, and the discharge capacity was recorded, which is the first discharge capacity. The battery was subjected to cyclic charge-discharge tests using the above method, and the discharge capacity after each cycle was recorded.

[0201] Battery capacity retention rate after 500 cycles (%) = Discharge capacity on the 500th cycle / Discharge capacity on the 1st cycle × 100%.

[0202] Table 2 presents the performance test results of Examples 1-19 and Comparative Examples 1-2.

[0203] Table 2

[0204]

[0205]

[0206] As can be seen from the test results in Table 2, when the coating containing the hydraulic inorganic material of this application is immersed in the electrolyte, the hydraulic inorganic material in the coating can react with the solvent water and fully harden the coating, thereby significantly increasing the tensile strength of the separator. Therefore, the separator is not easily deformed during the battery formation process and during cyclic charging and discharging, effectively suppressing the collapse of the central hole and dendrite growth, and improving the safety and cycle performance of the battery. When the coating containing the hydraulic inorganic material of this application is immersed in the electrolyte, it can also release a suitable amount of heat, thereby increasing the transport speed of active ions between the positive and negative electrodes of the battery and improving the rate performance of the battery.

[0207] In Comparative Example 2, an alumina ceramic coating was applied to the surface of the base film. Although this could increase the compressive strength of the separator to some extent, the compressive strength of the separator was low and could not effectively suppress the collapse of the central hole, resulting in a small improvement in the battery cycle performance.

[0208] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An electrode assembly for a battery, the battery comprising an electrolyte comprising an electrolyte salt and water. The electrode assembly includes: First electrode plate; A second electrode with the opposite polarity to the first electrode; as well as A separator is disposed between the first electrode and the second electrode. in, The electrode assembly is obtained by winding a first electrode, a second electrode, and a separator. The separator includes a base membrane and a coating disposed on at least a portion of the surface of the base membrane. The coating comprises a hydraulic inorganic material that can harden by reacting with water. The coating is disposed only in the region from 0 cm to L cm from the starting end of the separator winding, where 10 ≤ L ≤ 20. The hydraulic inorganic material includes at least one compound of Formula 1. First oxide · a Second oxide · b Sulfate · c Halide formula 1 in, 0 < a ≤ 6, 0 ≤ b ≤ 4, 0 ≤ c ≤ 4 The first oxide is represented by CaO or BaO. The second oxide represents component 1, component 2, or a combination thereof. Component 1 represents SiO2, Al2O3, Fe2O3, or a combination of two or more thereof, and component 2 represents FeO, MgO, BaO, K2O, Na2O, TiO2, CuO, Cr2O3, P2O5, SO3, or a combination of two or more thereof. Sulfates represent CaSO4, MgSO4, BaSO4, SrSO4, ZnSO4, Al2(SO4)3, FeSO4, Fe2(SO4)3, or combinations of two or more thereof. Halides are represented by CaCl2, CaF2, or combinations thereof.

2. The electrode assembly according to claim 1, wherein, The mass ratio of component 1 to component 2 is (95~100):(0~5).

3. The electrode assembly according to claim 1, wherein, The hydraulic inorganic material includes one or more compounds represented by formulas 1-1 to 1-8. CaO·a1 SiO2·b Sulfate·c Halides (Formula 1-1) CaO·a2 Al2O3·b Sulfate·c Halides (Formula 1-2) CaO·a3 Fe2O3·b Sulfate·c Halides (Formulas 1-3) CaO·a4 Al2O3·a5 SiO2·b Sulfate·c Halides (Formulas 1-4) CaO·a6, Al2O3·a7, Fe2O3·b, sulfate·c, halide formulas 1-5 BaO·a8SiO2·bSulfate·cHalide (Formulas 1-6) BaO·a9Al2O3·bSulfate·cHalide (Formulas 1-7) BaO·a10 Al2O3·a11 SiO2·b Sulfate·c Halides (Formulas 1-8) in, 0＜a1≤6， 0＜a2≤6， 0＜a3≤6， 0 < a4 < 6, 0 < a5 < 6, and 0 < a4 + a5 ≤ 6. 0 < a6 < 6, 0 < a7 < 6, and 0 < a6 + a7 ≤ 6. 0＜a8≤6， 0＜a9≤6， 0 < a10 < 6, 0 < a11 < 6, and 0 < a10 + a11 ≤ 6. 0≤b≤4， 0≤c≤4， Sulfates represent CaSO4, MgSO4, BaSO4, SrSO4, ZnSO4, Al2(SO4)3, FeSO4, Fe2(SO4)3, or combinations of two or more thereof. Halides are represented by CaCl2, CaF2, or combinations thereof.

4. The electrode assembly according to claim 1 or 3, wherein, b = 0, and / or, c＝0。 5. The electrode assembly according to claim 1, wherein, The hydraulic inorganic materials include 2CaO·SiO2, 3CaO·SiO2, CaO·Al2O3, CaO·2Al2O3, 3CaO·Al2O3, 6CaO·2Al2O3, 12CaO·7Al2O3, CaO·Fe2O3, 2CaO·Fe2O3, 2CaO·Al2O3·SiO2, CaO·Al2O3·2SiO2, 4CaO·Al2O3·Fe2O3, 6CaO·Al2O3·2Fe2O3, 3CaO·3Al2O3·CaSO4, 3CaO·3Al2O3·MgSO4, 3CaO·3Al2O3·BaSO4, 3CaO·3Al2O3·SrSO4, 3CaO O·3Al2O3·ZnSO4, 3CaO·3Al2O3·Al2(SO4)3, 3CaO·3Al2O3·FeSO4, 3CaO·3Al2O3·Fe2(SO4)3, 2CaO·SiO2·CaSO4, 11CaO·7Al2O3·CaF2, 3CaO·3Al2O3·CaF 2. One or more of CaO·3Al2O3·3CaF2, CaO·3Al2O3·4CaF2, 2BaO·SiO2, 3BaO·SiO2, BaO·Al2O3, 3BaO·Al2O3, BaO·6Al2O3, BaO·Al2O3·SiO2, BaO·Al2O3·2SiO2.

6. The electrode assembly according to claim 5, wherein, The hydraulic inorganic material includes one or more of 2CaO·SiO2, 3CaO·SiO2, 3CaO·Al2O3, and 4CaO·Al2O3·Fe2O3.

7. The electrode assembly according to claim 1, wherein, The hydraulic inorganic material is a particle with a volumetric particle size Dv10 of 1μm to 10μm.

8. The electrode assembly according to claim 7, wherein, The hydraulic inorganic material is a particle with a volumetric particle size Dv10 of 3μm to 5μm.

9. The electrode assembly according to claim 1, wherein, Based on the total mass of the coating, the mass percentage of the hydraulic inorganic material is 95%~100%.

10. The electrode assembly according to claim 9, wherein, Based on the total mass of the coating, the mass percentage of the hydraulic inorganic material is 97% to 100%.

11. The electrode assembly according to claim 1, wherein, The coating also includes additives, which include one or more of the following: water-reducing agents, gypsum, volcanic ash, fly ash, slag, quartz sand, limestone, and clay.

12. The electrode assembly according to claim 11, wherein, Based on the total mass of the coating, the mass percentage of the additive is ≤5%.

13. The electrode assembly according to claim 12, wherein, Based on the total mass of the coating, the mass percentage of the additive is ≤3%.

14. The electrode assembly according to claim 1, wherein, The total thickness of the coating is 0.5 μm to 5 μm, and / or, The thickness of the base film is 5μm~12μm.

15. The electrode assembly of claim 14, wherein, The total thickness of the coating is 0.5 μm to 2 μm, and / or, The thickness of the base film is 6μm~7μm.

16. The electrode assembly according to claim 1, wherein, The base membrane is selected from one or more of polyolefin porous membranes, nonwoven fabrics, and glass fibers.

17. The electrode assembly according to claim 1, wherein, The heat of hydration of the coating within 2 days of its reaction with water is 300 J / g ~ 500 J / g, and / or, The compressive strength of the coating after it reacts with water and hardens is 2500Pa ~ 20000Pa.

18. The electrode assembly according to claim 17, wherein, The compressive strength of the coating after it reacts with water and hardens is 2500 Pa ~ 10000 Pa.

19. A battery comprising an electrode assembly and an electrolyte, wherein, The electrode assembly is the electrode assembly according to any one of claims 1-18, and the electrolyte comprises an electrolyte salt and water.

20. The battery according to claim 19, wherein, The battery is a lithium-ion battery, sodium-ion battery, potassium-ion battery, zinc-ion battery, calcium-ion battery, magnesium-ion battery, aluminum-ion battery, or a hybrid-ion battery.

21. A battery module comprising the battery according to claim 19 or 20.

22. A battery pack comprising one of the battery according to claim 19 or 20 and the battery module according to claim 21.

23. An electrical device comprising at least one of the battery according to claim 19 or 20, the battery module according to claim 21, and the battery pack according to claim 22.

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