Battery monomer and preparation method thereof, battery device and power utilization device

Abstract

The invention discloses a battery monomer, a preparation method thereof, a battery device and a power utilization device. The battery monomer comprises an isolating membrane, the isolating membrane comprises a base membrane and a coating, the coating is arranged on the surface of at least one side of the base membrane, the coating comprises a porous material, the specific surface area S of the porous material meets the condition that S is larger than or equal to 100 m < 2 > / g and smaller than or equal to 4000 m < 2 > / g, and in the porous material, the ratio V of the total volume of pores with the pore diameter ranging from 0.3 nm to 3 nm to the mass of the porous material meets the condition that V is larger than or equal to 0.02 mL / g. Therefore, the safety performance of the battery monomer is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a battery cell and its preparation method, a battery device, and an electrical device. Background Technology

[0002] With increasing environmental pollution, the new energy industry is attracting more and more attention. Within the new energy industry, battery technology is a crucial factor in its development.

[0003] The development of battery technology requires consideration of various design factors, such as energy density, cycle life, safety, and reliability. The design of the separator within a battery cell is crucial to its safety performance; therefore, providing a battery cell with high safety performance is a pressing technical challenge. Summary of the Invention

[0004] This application is made in view of the above-mentioned issues, and its purpose is to provide a battery cell that can reduce the risk of lithium plating and has high safety performance.

[0005] To achieve the above objectives, this application provides a battery cell, a method for preparing the same, a battery device, and an electrical device.

[0006] In a first aspect, a battery cell is provided, comprising: a separator, the separator comprising a base film and a coating, the coating being disposed on at least one surface of the base film, the coating comprising a porous material, the specific surface area S of the porous material satisfying: 100 m² / s. 2 / g≤S≤4000m 2 / g, and the ratio V of the total volume of pores with a pore size of 0.3nm to 3nm to the mass of the porous material satisfies: V≥0.02mL / g.

[0007] In this embodiment, a coating is provided on at least one side of the base film. The coating comprises a porous material, and the specific surface area S of the porous material satisfies: 100 m² / s. 2 / g≤S≤4000m 2 / g. Setting the specific surface area of ​​the porous material in the coating within the above-mentioned range can increase the contact area between the electrolyte and the porous material, thereby improving the wettability of the electrolyte to the separator and ensuring that the separator is fully wetted by the electrolyte. Furthermore, in the porous material, the ratio V of the total volume of pores with a pore size of 0.3nm to 3nm to the mass of the porous material satisfies: V ≥ 0.02mL / g. Pores with a pore size of 0.3nm to 3nm in the porous material are beneficial for containing electrolyte. Setting the ratio of the total volume of pores with a pore size of 0.3nm to 3nm to the mass of the porous material within the above-mentioned range can provide more channels for containing electrolyte, thereby increasing the electrolyte retention in the separator during the use of the battery cell. Therefore, the technical solution of this application embodiment can reduce the risk of lithium plating on the electrode due to poor separator wetting, thereby improving the safety performance of the battery cell.

[0008] In one possible implementation, the porous material includes at least one of a porous organic polymer containing amine groups, a conjugated microporous polymer containing oxygen-containing functional groups, a conjugated microporous polymer containing nitrogen-containing functional groups, and an inorganic porous material.

[0009] The aforementioned materials all possess numerous pores, and their application in coatings can effectively improve the wettability of the electrolyte to the separator. Furthermore, substances containing the aforementioned amine, oxygen-containing, or nitrogen-containing functional groups exhibit electrolyte affinity, which can further enhance the wettability of the electrolyte to the separator.

[0010] In one possible implementation, the porous organic polymer containing amine groups includes at least one of melamine-terephthalaldehyde polymer and melamine-tetrafluorobenzene polymer.

[0011] In one possible implementation, the oxygen-containing functional group includes at least one of hydroxyl, carbonyl, and carboxyl groups, and the nitrogen-containing functional group includes at least one of amino and imine groups.

[0012] In one possible implementation, the inorganic porous material includes at least one of a compound containing a sulfonic acid group, a compound containing an amine group, and a compound containing a phosphate group.

[0013] In one possible implementation, the coating further includes a first adhesive, which includes at least one of polyurethane, polyacrylate, and polyurethane-polyoxypropylene copolymer.

[0014] On the one hand, the first binder provides adhesion between the porous material and the coating and the base film to improve the structural stability of the separator; on the other hand, the substances that can be used as the first binder include groups with electrolyte-loving properties, which can further improve the wettability of the electrolyte to the separator.

[0015] In one possible implementation, the coating further includes a conduit material, the pore size of which is... satisfy: The length L of the catheter material satisfies: L≤2μm.

[0016] On the one hand, the pore size of the conduit material Within the aforementioned range, the conduit material provides a rapid wetting channel for the electrolyte, reducing the wetting path of the electrolyte within the separator and increasing the wetting rate of the electrolyte during the use of the battery cell. On the other hand, setting the length L of the conduit material within the aforementioned range reduces the risk of the conduit material puncturing the separator while providing a rapid wetting channel for the electrolyte.

[0017] In one possible implementation, the conduit material includes at least one of carbon nanotube / polypropylene conduit, nanoporous graphene, graphene nanosheet stacked material, carbon nanotube, graphene aerogel, mesoporous silica, mesoporous metal oxide, metal oxide nanotube, molecular wire, silicon nanowire, and polyimide nanotube.

[0018] The chemical structures of the aforementioned substances contain conduit or pore structures, which provide rapid wetting channels for electrolyte, reduce the wetting path of the electrolyte in the separator, and increase the wetting rate of the electrolyte during battery use.

[0019] In one possible implementation, the metal oxide nanotubes include at least one of alumina nanotubes, titanium dioxide nanotubes, zinc oxide nanotubes, and titanium oxide nanotubes.

[0020] In one possible implementation, the coating further includes a second adhesive comprising at least one of polyacrylate, polyacrylic acid, polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride-trichloroethylene copolymer, polyvinylpyrrolidone, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyethylene oxide, polyarylate, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, polyacrylonitrile, polyvinyl alcohol, polyethylene, polypropylene, starch, or cyanoethyl amylopectin.

[0021] The aforementioned substances have good adhesion properties, providing good adhesion between the various substances in the coating and between the base film and the coating, further improving the structural stability of the separator.

[0022] In one possible implementation, the separator further includes a first adhesive layer disposed on the surface of the coating on the side away from the base film. The first adhesive layer includes at least one of polyacrylate, polyacrylic acid, polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride-trichloroethylene copolymer, polyvinylpyrrolidone, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyethylene oxide, polyarylate, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, polyacrylonitrile, polyvinyl alcohol, polyethylene, polypropylene, starch, or cyanoethyl amylopectin.

[0023] In the above scheme, a first adhesive layer is provided on the side of the coating away from the base film to improve the adhesion between the separator and the adjacent electrode, thereby improving the structural stability of the electrode assembly.

[0024] In one possible implementation, the isolation membrane further includes an insulating layer, the base film includes a first surface and a second surface disposed opposite to each other, the coating is disposed on the first surface, and the insulating layer is disposed on the second surface.

[0025] In the above scheme, a coating containing porous material is provided on one side of the base membrane to improve the electrolyte wetting performance of the separator, and an insulating layer is provided on the other side of the base membrane. The insulating layer has good structural strength and can reduce the risk of the separator being punctured when the battery is lithium-plated or structurally damaged.

[0026] In one possible implementation, the insulating layer comprises at least one of electronically insulating inorganic materials and electronically insulating organic materials.

[0027] In one possible implementation, the electronically insulating inorganic material includes at least one of Al3O2, TiO2, MgO, SiO2, SnO2, CeO2, ZrO2, BaTiO3, Y2O3, and boehmite.

[0028] In one possible implementation, the electronically insulating organic material includes at least one of polyethylene, polypropylene, cellulose, polyimide, polyethylene oxide, polymethyl methacrylate, polyvinyl chloride, polyacrylonitrile, polyvinylidene fluoride, polypropylene oxide, polyvinylidene chloride, and polycarbonate.

[0029] In one possible implementation, the separator further includes a second adhesive layer disposed on the surface of the insulating layer on the side away from the base film. The second adhesive layer includes at least one of polyacrylate, polyacrylic acid, polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride-trichloroethylene copolymer, polyvinylpyrrolidone, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyethylene oxide, polyarylate, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, cellulose acetate, cellulose propionate acetate, cellulose acetate butyrate, polyacrylonitrile, polyvinyl alcohol, polyethylene, polypropylene, starch, or cyanoethyl amylopectin.

[0030] In the above scheme, a second adhesive layer is provided on the surface of the insulating layer away from the base film to improve the adhesion between the separator and the adjacent electrode, thereby improving the structural stability of the electrode assembly.

[0031] In one possible implementation, the thickness D of the coating satisfies: 1μm≤D≤3μm.

[0032] In this embodiment, the thickness of the coating is set within the above-mentioned range so that the overall thickness of the separator is within a suitable range, so as to prepare a battery cell of suitable size. This solution takes into account both the wettability of the separator and the size requirements of the battery cell.

[0033] Secondly, a method for preparing a battery cell is provided, comprising: providing a separator to prepare the battery cell; wherein providing the separator includes: preparing a coating slurry, wherein the coating slurry comprises a porous material, and the specific surface area S of the porous material satisfies: 100 m² / s. 2 / g≤S≤4000m 2 / g, and the ratio V of the total volume of pores with a pore size of 0.3nm to 3nm to the mass of the porous material satisfies: V≥0.02mL / g; the slurry of the coating is applied to at least one side of the surface of the base film to provide the isolation membrane.

[0034] The above-mentioned method for preparing the separator is relatively simple and has low complexity. Furthermore, when the prepared separator is applied to a battery cell, it can reduce the risk of lithium plating in the battery cell and improve the safety performance of the battery cell.

[0035] Thirdly, a battery device is provided, comprising a battery cell according to the first aspect and any possible implementation thereof, and / or a battery cell obtained by a preparation method according to the second aspect and any possible implementation thereof.

[0036] Fourthly, an electrical device is provided, including the battery device of the third aspect.

[0037] In one possible implementation, the battery device includes a vehicle, a ship, or a spacecraft. Vehicles, ships, and spacecraft have high requirements for the safety performance of individual battery cells; applying individual battery cells to these electrical devices can improve the safety performance of the devices. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced 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.

[0039] Figure 1 This is a schematic diagram of the structure of the separator according to an embodiment of this application;

[0040] Figure 2 This is a schematic diagram of the structure of the separator according to an embodiment of this application;

[0041] Figure 3 This is a schematic diagram of the structure of the separator membrane according to an embodiment of this application;

[0042] Figure 4 This is a schematic diagram of the structure of the separator membrane according to an embodiment of this application;

[0043] Figure 5 This is a schematic diagram of the structure of a battery cell according to an embodiment of this application;

[0044] Figure 6 This is a schematic flowchart illustrating a method for preparing a single battery cell according to an embodiment of this application;

[0045] Figure 7 This is a schematic diagram of the structure of a battery device according to an embodiment of this application;

[0046] Figure 8 This is a schematic diagram of the structure of a vehicle according to an embodiment of this application;

[0047] Figure 9 This is a scanning electron microscope image of a porous material, melamine-terephthalaldehyde polymer, according to an embodiment of this application.

[0048] Figure 10 This is a scanning electron microscope image of a porous material, melamine-tetrafluorobenzene polymer, according to an embodiment of this application. Detailed Implementation

[0049] The battery cell and its preparation method, battery device, and power-consuming device embodiments of this application have been described in detail with appropriate reference to the accompanying drawings. 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 to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0050] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0051] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0052] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0053] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0054] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0055] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0056] 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.

[0057] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0058] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0059] 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.

[0060] Typically, a battery cell includes a positive electrode, a negative electrode, an electrolyte, and a separator. During the charging and discharging process, active ions move back and forth between the positive and negative electrodes, inserting and extracting. The electrolyte acts as a conductor of ions between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, primarily prevents short circuits while allowing active ions to pass through.

[0061] In this application's embodiments, a single battery cell can refer to the smallest structural unit of a battery. Multiple battery cells can first be assembled into a battery module, and then the battery module can be assembled into a battery; multiple battery cells can also be directly assembled into a battery.

[0062] In this application's embodiments, the battery cell refers to a lithium-ion secondary battery, that is, a lithium-ion battery cell capable of reversible charging and discharging.

[0063] During the charging process of a lithium-ion battery, lithium ions are released from the positive electrode active material, move and embed into the negative electrode material; while during the discharging process, lithium ions are released from the negative electrode material, move and embed into the positive electrode active material.

[0064] It should be understood that the “intercalation” process described in this application refers to the process in which lithium ions are intercalated in the positive electrode active material and the negative electrode material due to an electrochemical reaction, and the “deintercalation” and “deintercalation” processes described in this application refer to the process in which lithium ions are deintercalated in the positive electrode active material and the negative electrode material due to an electrochemical reaction.

[0065] The development of battery technology must consider multiple design factors simultaneously, such as energy density, cycle life, discharge capacity, charge / discharge rate, and reliability. A battery cell includes a separator, which separates the positive and negative electrodes to prevent short circuits. The wettability of the separator is a crucial factor affecting battery performance. Insufficient separator wetting hinders the passage of metal ions (e.g., lithium ions), impeding their free movement between the positive and negative electrodes and thus affecting battery performance. Furthermore, insufficient electrolyte wetting of the separator can lead to lithium plating, compromising battery safety.

[0066] In view of this, this application provides a battery cell. The separator of the battery cell includes a base film and a coating, the coating being disposed on at least one surface of the base film, and the coating comprising a porous material, wherein the specific surface area S of the porous material satisfies: 100 m² / s. 2 / g≤S≤4000m 2 / g, and in the porous material, the ratio V of the total volume of pores with a pore size of 0.3nm to 3nm to the mass of the porous material satisfies: V≥0.02mL / g. In the embodiments of this application, setting the specific surface area of ​​the porous material in the coating within the above range can increase the contact area between the electrolyte and the porous material, thereby improving the wettability of the electrolyte to the separator, allowing the separator to be fully wetted by the electrolyte. Furthermore, pores with a pore size of 0.3nm to 3nm in the porous material are beneficial for containing electrolyte, and setting the ratio of the total volume of pores with a pore size of 0.3nm to 3nm to the mass of the porous material within the above range can provide more channels for containing electrolyte, thereby increasing the amount of electrolyte retained in the separator during the use of the battery cell. Therefore, the technical solution of the embodiments of this application can reduce the risk of lithium plating on the electrode due to poor separator wetting, thereby improving the safety performance of the battery cell.

[0067] [Battery cell]

[0068] This application provides a battery cell including a separator.

[0069] Figure 1 This is a schematic diagram of the structure of a separator membrane according to an embodiment of this application. For example, as... Figure 1 As shown, the separator 1 includes a base film 10 and a coating 11 disposed on at least one side of the surface of the base film 10.

[0070] The base film 10 has two opposing surfaces along its thickness direction. The coating 11 can be disposed on one surface of the base film 10 or on both surfaces of the base film 10. As an example, such as... Figure 1 As shown, coating 11 is disposed on both sides of the base film 10.

[0071] Coating 11 comprises a porous material, the specific surface area S of which satisfies: 100 m² 2 / g≤S≤4000m 2 / g.

[0072] For example, the specific surface area S of the porous material can be 100 m². 2 / g, 150m 2 / g、200m 2 / g、300m 2 / g、400m 2 / g、500m 2 / g, 1000m 2 / g、2000m 2 / g、3000m 2 / g、4000m 2 / g, or its value is within the range obtained by combining any two of the above values.

[0073] In this embodiment, setting the specific surface area of ​​the porous material in the coating 11 within the above-mentioned range can increase the contact area between the electrolyte and the porous material, thereby improving the wettability of the electrolyte on the separator 1, so that the separator 1 is fully wetted by the electrolyte.

[0074] In porous materials, the ratio V of the total volume of pores with a pore size of 0.3 nm to 3 nm to the mass of the porous material satisfies: V ≥ 0.02 mL / g.

[0075] In porous materials, pores with a diameter of 0.3 nm to 3 nm are beneficial for containing electrolyte. When the ratio of the total volume of pores with a diameter of 0.3 nm to 3 nm to the mass of the porous material is within the above range, more channels for containing electrolyte can be provided, thereby increasing the electrolyte retention in the separator 1 during the use of the battery cell.

[0076] For example, the porous material can be at least one of porous organic polymers, conjugated microporous polymers, and inorganic porous materials.

[0077] In this embodiment, conjugated microporous polymers are a class of polymeric materials with both conjugated and microporous structures. The molecular structure of conjugated microporous polymers contains conjugated bonds, which can form π-π electron stacking, thereby creating a conjugated system within the material. For example, polybenzimidazole is a conjugated microporous polymer prepared from benzimidazole monomers through a polymerization reaction.

[0078] In this embodiment, a coating 11 is provided on at least one side of the base film 10. The coating 11 comprises a porous material, and the specific surface area S satisfies: 100 m² / s. 2 / g≤S≤4000m 2 The porous material has a total volume of pores with a pore size of 0.3 nm to 3 nm, and the ratio V of the total volume of the porous material to the mass of the porous material satisfies: V ≥ 0.02 mL / g. The coating 11 includes the aforementioned porous material, which on the one hand improves the wettability of the electrolyte to the separator, ensuring sufficient wettability of the separator; on the other hand, it increases the electrolyte retention in the separator. Therefore, the technical solution of this application embodiment can reduce the risk of lithium plating on the electrode due to poor separator wettability, thereby improving the safety performance of the battery cell.

[0079] In some embodiments, the porous organic polymer includes a porous organic polymer containing amine groups.

[0080] For example, the porous organic polymer containing amine groups may include at least one of melamine-terephthalaldehyde polymer and melamine-tetrafluorobenzene polymer.

[0081] In the embodiments of this application, the melamine-terephthalaldehyde polymer is a polymer obtained by polymerizing melamine and terephthalaldehyde, the melamine-tetrafluorobenzene polymer is a polymer obtained by polymerizing melamine and tetrafluoroterephthalaldehyde, and the melamine-tetrafluorobenzene polymer can also be obtained by polymerizing melamine and tetrafluoroterephthalic acid. The specific synthesis methods of the above polymers will be described in detail below.

[0082] The solvent for the electrolyte typically includes organic solvents, such as at least one selected from ethylene carbonate, dimethyl carbonate, ethyl methyl carbonate, and propylene carbonate. Substances containing amine groups have electrolyte-loving properties and can better adsorb the electrolyte. When the coating 11 includes a porous organic polymer containing amine groups, on the one hand, the porous organic polymer can provide more pores, which is beneficial for electrolyte wetting; on the other hand, due to the presence of amine groups, the porous organic polymer has electrolyte-loving properties and can better adsorb the electrolyte, further facilitating electrolyte wetting.

[0083] In some embodiments, the conjugated microporous polymer includes at least one of a conjugated microporous polymer containing oxygen-containing functional groups and a conjugated microporous polymer containing nitrogen-containing functional groups.

[0084] Substances containing oxygen-containing functional groups have electrophilic properties and can better adsorb electrolytes. When the coating 11 includes a conjugated microporous polymer containing oxygen-containing functional groups, on the one hand, the conjugated microporous polymer can provide more channels, which is beneficial to electrolyte wetting; on the other hand, due to the presence of oxygen-containing functional groups, the conjugated microporous polymer has electrophilic properties and can better adsorb electrolytes, further facilitating electrolyte wetting.

[0085] In some embodiments, the oxygen-containing functional group includes at least one of hydroxyl, carbonyl, and carboxyl groups.

[0086] Substances containing nitrogen-containing functional groups have electrophilic properties and can better adsorb electrolytes. When the coating 11 includes a conjugated microporous polymer containing nitrogen-containing functional groups, on the one hand, the conjugated microporous polymer can provide more channels, which is beneficial to electrolyte wetting; on the other hand, due to the presence of nitrogen-containing functional groups, the conjugated microporous polymer has electrophilic properties and can better adsorb electrolytes, further facilitating electrolyte wetting.

[0087] In some embodiments, the nitrogen-containing functional group includes at least one of amino and imine groups.

[0088] In some embodiments, the inorganic porous material includes at least one of a compound containing a sulfonic acid group, a compound containing an amino group, and a compound containing a phosphate group.

[0089] In some embodiments, coating 11 further includes a first adhesive, which includes at least one of polyurethane, polyacrylate, and polyurethane-polyoxypropylene copolymer.

[0090] On the one hand, the first binder provides adhesion between the porous material and the coating 11 and the base film 10 to improve the structural stability of the separator 1; on the other hand, the substances that can be used as the first binder include groups with electrolyte-loving properties, which can further improve the wettability of the electrolyte to the separator 1.

[0091] In some embodiments, coating 11 further includes a conduit material, the pore size of which is specified in the conduit material. satisfy: The length L of the catheter material satisfies: L≤2μm.

[0092] For example, the pore size of the conduit material The wavelength can be 0.3nm, 0.5nm, 1nm, 1.2nm, 1.5nm, 2nm, 2.5nm, 2.7nm, 3nm, or a value within the range obtained by any combination of the above two values.

[0093] For example, the length L of the catheter material can be 0.5μm, 1μm, 1.2μm, 1.5μm, 1.7μm, 1.8μm, 2μm, or a value within the range obtained by any combination of the above two values.

[0094] On the one hand, the pore size of the conduit material By setting the length L of the conduit material within the aforementioned range, a rapid wetting channel can be provided for the electrolyte, reducing the wetting path of the electrolyte in the separator 1 and increasing the wetting rate of the electrolyte during the use of the battery cell. On the other hand, by setting the length L of the conduit material within the aforementioned range, a rapid wetting channel for the electrolyte is provided while reducing the risk of the conduit material puncturing the separator 1.

[0095] In some embodiments, the conduit material includes at least one of carbon nanotube / polypropylene conduit, graphene nanopore conduit, graphene nanosheet stack, carbon nanotube, graphene aerogel, mesoporous silica, mesoporous metal oxide, metal oxide nanotube, molecular wire, silicon nanowire, and polyimide nanotube.

[0096] The chemical structure of the above-mentioned substances has a conduit structure or a pore structure, which provides a rapid wetting channel for the electrolyte, reduces the wetting path of the electrolyte in the separator 1, and improves the wetting rate of the electrolyte during battery use.

[0097] In some embodiments, the metal oxide nanotubes include at least one of alumina nanotubes, titanium dioxide nanotubes, zinc oxide nanotubes, and titanium oxide nanotubes.

[0098] In some embodiments, coating 11 further includes a second adhesive, the second adhesive comprising at least one of polyacrylate, polyacrylic acid, polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride-trichloroethylene copolymer, polyvinylpyrrolidone, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyethylene oxide, polyarylate, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, polyacrylonitrile, polyvinyl alcohol, polyethylene, polypropylene, starch, or cyanoethyl amylopectin.

[0099] The aforementioned substances have good adhesive properties, providing good adhesion between the various substances in the coating 11 and between the base film 10 and the coating 11, thereby further improving the structural stability of the separator 1.

[0100] In some embodiments, such as Figure 2 As shown, the separator 1 further includes a first adhesive layer 12, which is disposed on the surface of the coating 11 away from the base film 10. The first adhesive layer 12 includes at least one of polyacrylate, polyacrylic acid, polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride-trichloroethylene copolymer, polyvinylpyrrolidone, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyethylene oxide, polyarylate, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, polyacrylonitrile, polyvinyl alcohol, polyethylene, polypropylene, starch, or cyanoethyl amylopectin.

[0101] In the above scheme, a first adhesive layer 12 is provided on the side of the coating 11 away from the base film 10 to improve the adhesion between the separator 1 and the adjacent electrode, thereby improving the structural stability of the electrode assembly.

[0102] In some embodiments, such as Figure 3 and Figure 4 As shown, the isolation membrane 1 also includes an insulating layer 13, and the base membrane 10 includes a first surface 101 and a second surface 102 disposed opposite to each other. The coating 11 is disposed on the first surface 101, and the insulating layer 13 is disposed on the second surface 102.

[0103] In this embodiment, a coating 11 containing porous material is provided on one side of the base film 10 to improve the electrolyte wetting performance of the separator 1, and an insulating layer 13 is provided on the other side of the base film 10. The insulating layer 13 has good structural strength and can reduce the risk of the separator 1 being punctured when the battery is lithium-plated or the structure is damaged.

[0104] In some embodiments, the insulating layer 13 includes at least one of electronic insulating inorganic material and electronic insulating organic material.

[0105] In some embodiments, the electronic insulating inorganic material includes at least one of Al3O2, TiO2, MgO, SiO2, SnO2, CeO2, ZrO2, BaTiO3, Y2O3, and boehmite.

[0106] In some embodiments, the electronically insulating organic material includes at least one of polyethylene, polypropylene, cellulose, polyimide, polyethylene oxide, polymethyl methacrylate, polyvinyl chloride, polyacrylonitrile, polyvinylidene fluoride, polypropylene oxide, polyvinylidene chloride, and polycarbonate.

[0107] In some embodiments, continue to refer to Figure 3 and Figure 4 The separator 1 further includes a second adhesive layer 14, which is disposed on the surface of the insulating layer 13 away from the base film 10. The second adhesive layer 14 includes at least one of polyacrylate, polyacrylic acid, polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride-trichloroethylene copolymer, polyvinylpyrrolidone, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyethylene oxide, polyarylate, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, polyacrylonitrile, polyvinyl alcohol, polyethylene, polypropylene, starch, or cyanoethyl amylopectin.

[0108] In the above scheme, a second adhesive layer 14 is provided on the surface of the insulating layer 13 away from the base film 10 to improve the adhesion between the separator 1 and the adjacent electrode, thereby improving the structural stability of the electrode assembly.

[0109] In some embodiments, such as Figure 1-4 As shown, the thickness of coating 11 is D, and D satisfies: 1μm≤D≤3μm.

[0110] Specifically, D can be 1μm, 1.5μm, 1.8μm, 2μm, 2.2μm, 2.4μm, 2.5μm, 2.7μm, 3μm, or a value within the range obtained by any combination of the above two values.

[0111] In this embodiment, the thickness of the coating 11 is set within the above-mentioned range so that the overall thickness of the separator 1 is within a suitable range, so as to prepare a battery cell of suitable size. This solution takes into account both the wettability of the separator 1 and the size requirements of the battery cell.

[0112] This application does not impose any particular limitation on the shape of the battery cell; it can be cylindrical, square, or any other arbitrary shape. The battery cell can be a lithium-ion battery, a lithium-sulfur battery, a sodium-ion battery, a magnesium-ion battery, etc.

[0113] Figure 5 This is a schematic diagram of the structure of a battery cell according to an embodiment of this application. For example, as shown... Figure 5 As shown, the battery cell 3 is a square battery cell. The battery cell 3 includes a housing 31, an end cap assembly 32, and an electrode assembly 33 disposed in the housing 31.

[0114] The electrode assembly 33 can be made from a positive electrode, a negative electrode, and a separator 1 by a winding process or a stacking process.

[0115] End cap assembly 32 includes electrode terminals 322, such as Figure 5 As shown, the end cap assembly 32 includes two electrode terminals 322, one of which is a positive electrode terminal and the other is a negative electrode terminal.

[0116] The battery cell 3 also includes a current collector 34, which is used to connect the tab 332 and the electrode terminal 322 of the electrode assembly 33. For example, in the case of a positive electrode in this embodiment, one current collector 34 is used to connect the tab and the positive electrode terminal of the positive electrode, and another current collector 34 is used to connect the tab and the negative electrode terminal of the negative electrode.

[0117] In some embodiments, the battery cell 3 includes an electrode assembly 33, which includes an electrode assembly body 331 and a tab 332 extending from the electrode assembly body 331.

[0118] In some embodiments, individual battery cells can be assembled into a battery module. The number of individual battery cells contained in a battery module can be one or more, and the specific number can be selected by those skilled in the art based on the application and capacity of the battery module.

[0119] [Positive electrode plate]

[0120] The positive electrode includes a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector, the positive electrode film layer including a positive electrode active material.

[0121] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0122] In some embodiments, the positive current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0123] In some embodiments, the positive electrode active material may be a known positive electrode active material for lithium-ion batteries. As an example, the positive electrode active material may include at least one of the following materials: lithium phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for lithium-ion batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05At least one of O2 and its modified compounds. Examples of lithium phosphates with an olivine structure include, but are not limited to, lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0124] It should be noted that during the charging and discharging process of the battery, Li undergoes insertion / extraction and consumption, resulting in different molar contents of Li at different discharge states. In the examples of positive electrode active materials listed in this application, the molar contents of Li refer to the initial state of the material, i.e., the state before feeding. As the positive electrode material is applied to the battery system, the molar contents of Li will change after charge-discharge cycles. Similarly, in the examples of the first metal oxide, the second metal oxide, and the positive electrode active materials listed in this application, the molar contents of O are only theoretical values. Lattice oxygen release will cause changes in the molar contents of oxygen, resulting in fluctuations in the actual molar contents of O.

[0125] In some embodiments, the positive electrode film layer may optionally include a binder. As an example, the binder may include at least one selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene-propylene terpolymer, ethylene-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0126] In some embodiments, the positive electrode film may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0127] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0128] [Negative electrode plate]

[0129] The negative electrode sheet includes a negative current collector and a negative electrode film layer disposed on at least one surface of the negative current collector, the negative electrode film layer including a negative electrode active material.

[0130] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0131] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0132] In some embodiments, the negative electrode active material may be a negative electrode active material known in the art for use in batteries. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional 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.

[0133] In some embodiments, the negative electrode film layer may optionally include a binder. The binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0134] In some embodiments, the negative electrode film may optionally include a conductive agent. The conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0135] In some embodiments, the negative electrode film may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0136] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing and other processes.

[0137] [Electrolytes]

[0138] The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific restrictions on the type of electrolyte; it can be selected according to requirements. For example, the electrolyte can be liquid, gel, or entirely solid.

[0139] In some embodiments, the electrolyte is an electrolyte solution. The electrolyte solution includes an electrolyte salt and a solvent.

[0140] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0141] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0142] 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 may also include additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.

[0143] In some implementations, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly using a winding or stacking process.

[0144] [Preparation methods for battery cells]

[0145] Figure 6 This is a schematic flowchart illustrating a method for preparing a battery cell according to an embodiment of this application. (In conjunction with...) Figure 6 As shown, the method 600 for preparing a single battery cell may include the following steps.

[0146] Step 610: Provide a separator to prepare a battery cell.

[0147] The provision of the isolation membrane includes: preparing a slurry for the coating, wherein the slurry comprises a porous material, and the specific surface area S of the porous material satisfies: 100 m² / s. 2 / g≤S≤4000m 2 / g, and in the porous material, the ratio V of the total volume of pores with a pore size of 0.3nm to 3nm to the mass of the porous material satisfies: V≥0.02mL / g; the coating slurry is applied to the surface of at least one side of the base film to provide an isolation membrane.

[0148] In the process of preparing the isolation membrane, an adhesive can also be added, and after mixing, a coating slurry is obtained.

[0149] As an example, a slurry for coating is applied to both sides of a base film to prepare a separating membrane.

[0150] In some embodiments, after step 610, the positive electrode sheet, negative electrode sheet, and separator can be prepared into an electrode assembly by winding or stacking, and then the electrode assembly is placed into a housing to prepare a battery cell.

[0151] In the method for preparing a battery cell according to the embodiments of this application, the resulting separator includes a porous material, and the specific surface area S of the porous material satisfies: 100m² 2 / g≤S≤4000m 2 / g, and in the porous material, the ratio V of the total volume of pores with a pore size of 0.3nm to 3nm to the mass of the porous material satisfies: V≥0.02ml / g. This can improve the electrolyte retention in the separator and the wettability of the electrolyte on the separator, ensuring that the separator is fully wetted by the electrolyte, reducing the risk of lithium plating on the electrode due to poor separator wetting, thereby improving the safety performance of the battery cell.

[0152] [Battery Device]

[0153] This application provides a battery device, including the battery cell described in the above embodiments. The battery cell can be a battery cell after formation and aging processes. Figure 7 This is a schematic diagram of the structure of a battery device according to an embodiment of this application. Figure 7 As shown, the battery device 5 may include multiple battery cells 3 to meet different power usage requirements. The shape of the battery cell 3 in this embodiment can be set according to actual application. For example, the battery cell 3 may be as follows: Figure 5 The cuboid shown can also be different. Figure 5 The embodiments shown are cylindrical or other shapes, but are not limited to these.

[0154] It should be understood that, such as Figure 7As shown, the battery device 5 in this embodiment may further include a housing 51, which can be used to accommodate multiple battery cells 3. The housing 51 in this embodiment has a hollow interior, and the multiple battery cells 3 are accommodated within the housing 51. The housing 51 may include two parts, referred to herein as a first housing portion 511 and a second housing portion 512, which are fastened together. The shapes of the first housing portion 511 and the second housing portion 512 can be determined according to the shape of the components housed inside, for example, according to the shape of the combination of the multiple battery cells 3 housed inside. At least one of the first housing portion 511 and the second housing portion 512 has an opening. For example, as... Figure 7 As shown, the first housing portion 511 and the second housing portion 512 can both be hollow cuboids with one open side. The openings of the first housing portion 511 and the second housing portion 512 are opposite to each other, and the first housing portion 511 and the second housing portion 512 are interlocked to form a housing 51 with a closed cavity, which can be used to accommodate multiple battery cells 3. The multiple battery cells 3 are connected in parallel, series, or mixed and placed inside the housing 51 formed by the interlocking of the first housing portion 511 and the second housing portion 512.

[0155] For example, unlike Figure 7 As shown, either the first housing portion 511 or the second housing portion 512 may have only one hollow cuboid with an opening, while the other is plate-shaped to cover the opening. Taking the second housing portion 512 as a hollow cuboid with one opening, and the first housing portion 511 as a plate-shaped example, then the first housing portion 511 covers the opening of the second housing portion 512 to form a housing 51 with a closed chamber, which can be used to accommodate multiple battery cells 3.

[0156] The battery cells 3 can be directly assembled into the battery device 5, or they can be first assembled into battery modules, and then multiple battery modules can be assembled into the battery device 5.

[0157] [Electrical appliances]

[0158] This application provides an electrical device, including the battery device described in the above embodiments.

[0159] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery devices.

[0160] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical devices.

[0161] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0162] For example, such as Figure 8 The diagram shown is a structural schematic of a vehicle 7 according to one embodiment of this application. The vehicle 7 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. The vehicle 7 can have a motor 4, a controller 6, and a battery device 5 installed inside. The controller 6 controls the battery device 5 to supply power to the motor 4. For example, the battery device 5 can be installed at the bottom, front, or rear of the vehicle 7. The battery device 5 can be used to power the vehicle 7; for example, it can serve as the operating power source for the vehicle 7's electrical system, such as meeting the power requirements for starting, navigation, and operation. In another embodiment of this application, the battery device 5 can not only serve as the operating power source for the vehicle 7 but also as the driving power source, replacing or partially replacing gasoline or natural gas to provide driving power to the vehicle 7.

[0163] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0164] 1. Preparation of porous materials

[0165] (1) Preparation of melamine-terephthalaldehyde polymer

[0166] 0.3138 g of melamine and 0.5030 g of terephthalaldehyde were added to 15 mL of dimethyl sulfoxide (DMSO) solvent and sonicated for 30 min to dissolve into a transparent solution. The resulting transparent solution was then added to a 20 mL polytetrafluoroethylene stainless steel reactor, sealed, and heated at 180 °C for 15 hours to obtain a white solid product. This white solid product was then washed sequentially with acetone, tetrahydrofuran, dichloromethane, and anhydrous methanol for 24 hours each, finally yielding a white powder product, a melamine-terephthalaldehyde polymer, with the following chemical structure: Figure 9 Both (a) and (b) are scanning electron microscope images of melamine-terephthalaldehyde polymer, differing only in the magnification.

[0167] (2) Preparation of melamine-tetrafluorobenzene polymer

[0168] In this embodiment, melamine-tetrafluorobenzene polymer is prepared using a solvothermal method, and the specific steps are as follows:

[0169] 0.5045 g of melamine and 0.3167 g of 2,3,5,6-tetrafluoroterephthalaldehyde were added to 16 mL of DMSO solvent and sonicated for 10 min to dissolve them into a pale yellow transparent solution. The resulting pale yellow transparent solution was then added to a 20 mL polytetrafluoroethylene stainless steel reactor, sealed, and heated at 180 °C for 15 hours to obtain a pale yellow solid product. The pale yellow solid product was washed sequentially with acetone, tetrahydrofuran, and dichloromethane for 24 hours each, finally yielding a white powder product, melamine-tetrafluorobenzene polymer, with the following chemical structure: Figure 10 Both (a) and (b) are scanning electron microscope images of melamine-tetrafluorobenzene polymer, differing only in the magnification.

[0170] In this embodiment, 2,3,5,6-tetrafluoroterephthalic acid can also be used instead of 2,3,5,6-tetrafluoroterephthalaldehyde to polymerize with melamine to generate melamine-tetrafluorobenzene polymer. The specific preparation method is the same as the above method and will not be repeated here.

[0171] 2. Preparation of the separating membrane

[0172] Separator 1:

[0173] A base film is provided, made of polyethylene (PE) and 7μm thick.

[0174] A coating slurry is provided: A porous melamine-terephthalaldehyde polymer and a first binder, polyurethane, are thoroughly mixed in an N-methylpyrrolidone (NMP) solvent at a mass ratio of 50:10 to form a coating slurry. This slurry is then applied to both sides of the PE base film to form a coating. The specific surface area S of the porous melamine-terephthalaldehyde polymer is 497 m². 2 / g, in the porous material melamine-terephthalaldehyde polymer, the ratio V of the total volume of pores with a pore size of 0.3nm to 3nm to the mass of the porous material is 0.2768mL / g, and the coating thickness is 2μm.

[0175] Separator 2: The preparation of separator 2 is similar to that of separator 1, except that the porous material in separator 2 is a melamine-tetrafluorobenzene polymer, and the specific surface area S of the melamine-tetrafluorobenzene polymer is 194 m². 2 / g, in the porous material melamine-tetrafluorobenzene polymer, the ratio of the total volume of pores with a pore size of 0.3nm to 3nm to the mass of the porous material is 0.0927mL / g.

[0176] Separator 3: Separator 3 is prepared in a similar manner to separator 1, except that the coating thickness in separator 3 is 1 μm.

[0177] Separator 4: Separator 4 is prepared in a similar manner to separator 1, except that the coating thickness in separator 4 is 3 μm.

[0178] Separator 5: Separator 5 is prepared similarly to separator 1, except that the coating in separator 5 also contains carbon nanotubes. The mass ratio of the porous material melamine-terephthalaldehyde polymer, polyurethane and carbon nanotubes is 30:10:20.

[0179] Separator 6: The difference between separator 6 and separator 1 is that separator 6 also includes a first adhesive layer, which is disposed on the surface of the coating away from the base film, and the first adhesive layer includes polyvinylidene fluoride (PVDF).

[0180] Separator 7:

[0181] A base film is provided, made of polyethylene (PE) and 7μm thick.

[0182] Provide coating slurry: The porous material melamine-terephthalaldehyde polymer and the first binder polyurethane are thoroughly mixed in an N-methylpyrrolidone solvent system at a mass ratio of 50:10 to form a coating slurry, which is then coated on one side of the PE base film to form a coating, wherein the thickness of the coating is 2μm.

[0183] Provide insulating slurry: Dissolve Al2O3 ceramic particles and styrene-polybutadiene rubber binder in solvent NMP at a mass ratio of 90:10, stir thoroughly and mix evenly to form an insulating slurry, and coat it on the other side of the above PE base film to form an insulating layer.

[0184] Separator 8: The difference between separator 8 and separator 7 is that separator 8 also includes a second adhesive layer, which is disposed on the surface of the insulating layer away from the base film, and the second adhesive layer includes PVDF.

[0185] Separator 9: Separator 9 is prepared similarly to separator 1, except that the coating of separator 9 does not include melamine-terephthalaldehyde polymer, and the coating material is polymethyl methacrylate (PMMA).

[0186] Separator 10: Separator 10 is prepared in a similar manner to separator 1, except that the coating of separator 10 contains only the binder PVDF.

[0187] 2. Preparation of battery cells

[0188] [Example 1]

[0189] (1) Preparation of positive electrode sheet

[0190] The active material lithium manganese oxide (LiMn2O4), the conductive agent acetylene black, and the binder PVDF are mixed thoroughly in an N-methylpyrrolidone solvent system at a mass ratio of 90%:5%:5%. The mixture is then coated onto an Al foil, dried, and cold-pressed to obtain the positive electrode sheet.

[0191] (2) Preparation of negative electrode sheet

[0192] The active material artificial graphite, the conductive agent acetylene black, and the binder PVDF are mixed thoroughly in an N-methylpyrrolidone solvent system at a mass ratio of 90%:5%:5%. The mixture is then coated onto a Cu foil, dried, and cold-pressed to obtain the negative electrode sheet.

[0193] (3) Separating membrane

[0194] The separator used is the separator 1 prepared above.

[0195] (4) Preparation of electrolyte

[0196] Ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed in a mass ratio of 30:70, and 1M lithium hexafluorophosphate (LiPF6) electrolyte salt was dissolved to obtain the electrolyte.

[0197] (5) Assembly of battery cells

[0198] The positive electrode, separator 1, and negative electrode are stacked in sequence, with separator 1 positioned between the positive and negative electrode to provide isolation. The electrode assembly is then wound to obtain an electrode assembly. The electrode assembly is placed in the battery casing, dried, and then injected with electrolyte. After formation and settling processes, a lithium-ion battery 1 is obtained, which is Example 1.

[0199] The secondary batteries of Examples 2-8 and Comparative Examples 1-2 were prepared using methods similar to those of the secondary battery of Example 1, except that different separators were used (separator 1-8 was used in Examples 1-8, and separator 9-10 was used in Comparative Examples 1-2), as detailed in Table 1. The performance parameters of Examples 1-8 and Comparative Examples 1-2 are also shown in Table 1.

[0200] Table 1. Product parameters and performance parameters of Examples 1-8 and Comparative Examples 1-2

[0201]

[0202]

[0203] Based on the results of Examples 1-8 and Comparative Examples 1-2, it can be seen that adding porous materials to the coating of the separator, with a specific surface area S of 100 m², results in a material that is 100 m² / s. 2 / g≤S≤4000m 2 / g, and in porous materials, the ratio V of the total volume of pores with a pore size of 0.3nm to 3nm to the mass of the porous material satisfies: V≥0.02mL / g, which can effectively improve the lithium plating problem of batteries.

[0204] The following is a brief description of the testing methods for the physicochemical and performance parameters involved in the embodiments of this application. It should be understood that the following testing methods are only examples, and other testing methods known in the art can also be used for testing.

[0205] 1. Measurement of specific surface area, pore size, and pore size distribution of porous materials.

[0206] The specific surface area, pore size, and pore size distribution of porous materials were tested using the 77K N2 adsorption method.

[0207] 2. Measurement of coating thickness

[0208] The thickness of the coating can be measured using a micrometer. The thickness of the coating is measured at multiple different locations using a micrometer, and the average of the multiple measurements is recorded as the final thickness.

[0209] The coating thickness in this embodiment can be measured using the methods described above, but is not limited to the methods described above. For example, it can also be measured using spectroscopy. For specific detection methods, refer to known methods for measuring thickness using spectroscopy.

[0210] 3. Morphology testing of porous materials

[0211] The porous materials in the examples were tested using a ZEISS Sigma 300 scanning electron microscope, and then the morphology of the samples was observed according to standard JY / T010-1996. The test results are shown below. Figure 9-10 .

[0212] 4. Does the battery cell plating lithium?

[0213] After cycling, the battery cells are disassembled to obtain the negative electrode sheet, which can be directly observed to see if lithium plating has occurred.

[0214] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A battery cell, characterized by, Comprise: An isolation film including a base film and a coating layer provided on at least one surface of the base film, the coating layer including a porous material, a specific surface area S of the porous material satisfying: 100 m 2 / g ≤ S ≤ 4000 m 2 / g, and a ratio V of a total volume of pores having a pore diameter of 0.3 nm to 3 nm in the porous material to a mass of the porous material satisfying: V ≥ 0.02 mL / g.

2. The battery cell of claim 1, wherein, The porous material comprises at least one of a porous organic polymer containing amine groups, a conjugated microporous polymer containing oxygen-containing functional groups, a conjugated microporous polymer containing nitrogen-containing functional groups, and an inorganic porous material.

3. The battery cell of claim 2, wherein, The porous organic polymer containing amine groups comprises at least one of melamine-p-phenylenformaldehyde polymer and melamine-tetrafluorobenzene polymer.

4. The battery cell according to claim 2 or 3, characterized in that, The oxygen-containing functional groups comprise at least one of hydroxyl groups, carbonyl groups, and carboxyl groups, and the nitrogen-containing functional groups comprise at least one of amino groups and imine groups.

5. The battery cell according to any one of claims 2 to 4, characterized in that, The inorganic porous material comprises at least one of a compound containing sulfonic acid groups, a compound containing amine groups, and a compound containing phosphoric acid groups.

6. The battery cell of any one of claims 1 to 5, wherein, The coating further comprises a first binder comprising at least one of polyurethane, polyacrylate, and polyurethane-polyoxypropylene copolymer.

7. The battery cell according to any one of claims 1 to 6, characterized in that, The coating further comprises a conduit material having a pore size φ satisfying 0.3 nm ≤ φ ≤ 3 nm and a length L satisfying L ≤ 2 μm.

8. The battery cell of claim 7, wherein, The conduit material comprises at least one of carbon nanotube / polypropylene conduit, nanoporous graphene, graphene nanosheet stack material, carbon nanotube, graphene aerogel, mesoporous silica, mesoporous metal oxide, metal oxide nanotube, molecular wire, silicon nanowire, and polyimine nanotube.

9. The battery cell of claim 8, wherein, The metal oxide nanotube comprises at least one of aluminum oxide nanotube, titanium dioxide nanotube, zinc oxide nanotube, and titanium oxide nanotube.

10. The battery cell of any one of claims 1 to 9, wherein, The coating further comprises a second binder comprising at least one of polyacrylate, polyacrylic acid, polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride-trichloroethylene copolymer, polyvinylpyrrolidone, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyethylene oxide, polyarylate, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, polyacrylonitrile, polyvinyl alcohol, polyethylene, polypropylene, starch, and cyanoethyl branched starch.

11. The battery cell of any one of claims 1 to 10, wherein, The coating further comprises a first adhesive layer disposed on a surface of the coating on a side distal from the base film, the first adhesive layer comprising at least one of polyacrylate, polyacrylic acid, polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride-trichloroethylene copolymer, polyvinylpyrrolidone, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyethylene oxide, polyarylate, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, polyacrylonitrile, polyvinyl alcohol, polyethylene, polypropylene, starch, and cyanoethyl branched starch.

12. The battery cell of any one of claims 1 to 11, wherein, The coating further comprises an insulating layer, the base film comprising a first surface and a second surface disposed opposite to each other, the coating being disposed on the first surface, and the insulating layer being disposed on the second surface.

13. The battery cell of claim 12, wherein, The insulating layer comprises at least one of an electronically insulating inorganic substance and an electronically insulating organic substance.

14. The battery cell of claim 13, wherein, The electronically insulating inorganic substance comprises at least one of Al3O2, TiO2, MgO, SiO2, SnO2, CeO2, ZrO2, BaTiO3, Y2O3, and boehmite.

15. The battery cell according to claim 13 or 14, characterized in that The electronic insulating organic substance includes at least one of polyethylene, polypropylene, cellulose, polyimide, polyethylene oxide, polymethyl methacrylate, polyvinyl chloride, polyacrylonitrile, polyvinylidene fluoride, polypropylene oxide, polyvinylidene chloride, polycarbonate.

16. The battery cell of any one of claims 12 to 15, wherein, The separator film further includes a second adhesive layer disposed on a surface of the insulating layer distal from the base film, the second adhesive layer including at least one of polyacrylate, polyacrylic acid, polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride-trichloroethylene copolymer, polyvinylpyrrolidone, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyethylene oxide, polyarylate, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, polyacrylonitrile, polyvinyl alcohol, polyethylene, polypropylene, starch, or cyanoethyl branched starch.

17. The battery cell of any one of claims 1 to 15, wherein, The thickness D of the coating layer satisfies: 1 pm ≤ D ≤ 3 pm.

18. A method of producing a battery cell, characterized by, The method of manufacturing the battery cell includes: providing a separator film to manufacture the battery cell; wherein the providing the separator film includes: A slurry for preparing a coating layer, wherein the slurry for the coating layer includes a porous material, a specific surface area S of the porous material satisfies: 100 m 2 / g ≤ S ≤ 4000 m 2 / g, and a ratio V of a total volume of pores having a pore diameter of 0.3 nm to 3 nm in the porous material to a mass of the porous material satisfies: V ≥ 0.02 mL / g. applying a slurry of the coating layer on a surface of at least one side of a base film to provide the separator film.

19. A battery device, characterized in that, The method of manufacturing the battery cell includes: The battery cell according to any one of claims 1 to 17, and / or the battery cell obtained by the method of manufacturing according to claim 18.

20. An electrical device, comprising: The battery device according to claim 19. The power consuming device includes a vehicle, a ship, or a spacecraft.

21. The powered device of claim 20, wherein, ​

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