WO2025145671A1 - 隔离膜及其制备方法、电池和用电装置 - Google Patents

隔离膜及其制备方法、电池和用电装置 Download PDF

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Publication number
WO2025145671A1
WO2025145671A1 PCT/CN2024/119787 CN2024119787W WO2025145671A1 WO 2025145671 A1 WO2025145671 A1 WO 2025145671A1 CN 2024119787 W CN2024119787 W CN 2024119787W WO 2025145671 A1 WO2025145671 A1 WO 2025145671A1
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Prior art keywords
dielectric material
material particles
battery
isolation film
coating
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English (en)
French (fr)
Inventor
游兴艳
白文龙
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/431—Inorganic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/457—Separators, membranes or diaphragms characterised by the material having a layered structure comprising three or more layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/491—Porosity

Definitions

  • the present application belongs to the field of batteries, and specifically relates to an isolation membrane and a preparation method thereof, a battery and an electrical device.
  • the present application provides an isolation membrane, aiming to improve the cycle performance of the battery containing the isolation membrane during the fast charging process.
  • the first aspect of the present application provides an isolation membrane, wherein the isolation membrane comprises:
  • the relative dielectric constant of the dielectric material particles is 1500-5000.
  • the cycle performance of the battery during the fast charging process can be further improved.
  • the dielectric material particles include at least one of barium titanate, lead titanate, lithium niobate, lead zirconate titanate, lead metaniobate, or lithium barium lead niobate, thereby improving the cycle performance of the battery during the fast charging process.
  • the mass proportion of the dielectric material particles is 20%-80%, and optionally 30%-70%.
  • the cycle performance of the battery during fast charging can be improved.
  • the thickness of the first coating layer is 0.5 ⁇ m-2 ⁇ m, and can be 0.8 ⁇ m-1.7 ⁇ m, thereby improving the cycle performance of the battery during fast charging.
  • the BET specific surface area of the dielectric material particles is 0.5 m 2 /g-6 m 2 /g, and can be 0.8 m 2 /g-4 m 2 /g.
  • the cycle performance of the battery during fast charging can be improved.
  • the first coating layer further includes a first binder, thereby improving the bonding performance between the first coating layer and the base film.
  • the first binder includes at least one of polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, or fluorine-containing acrylate resin.
  • the bonding performance of the first coating layer to the base film can be improved.
  • the isolation film further comprises a second coating layer, which is disposed on a side of the base film away from the first coating layer, and the second coating layer comprises inorganic particles, thereby improving the high temperature resistance of the isolation film.
  • the inorganic particles include at least one of silicon dioxide, aluminum oxide, zirconium dioxide, zinc oxide, magnesium oxide, sodium sulfate, barium sulfate, boehmite or calcium carbonate, and can be selected from at least one of silicon dioxide, aluminum oxide, boehmite, zirconium dioxide or barium sulfate.
  • the high temperature resistance of the isolation membrane can be improved.
  • the volume average particle size Dv50 of the inorganic particles is 0.5 ⁇ m-2.5 ⁇ m, and can be 0.8 ⁇ m-2.3 ⁇ m.
  • the high temperature resistance of the isolation film can be improved.
  • the thickness of the second coating layer is 0.5 ⁇ m-4 ⁇ m, and can be 1 ⁇ m-2 ⁇ m, thereby improving the high temperature resistance of the isolation film.
  • the mass proportion of the inorganic particles is 30%-70%, and optionally 40%-60%.
  • the high temperature resistance of the isolation film can be improved.
  • the second coating layer includes a second binder, thereby improving the bonding performance between the second coating layer and the base film.
  • a method for preparing an isolation film comprising: forming a first coating layer comprising dielectric material particles on one side of a base film to obtain an isolation film, wherein the relative dielectric constant of the dielectric material particles is 1000-10000.
  • the battery using the isolation membrane obtained by the method has excellent cycle performance during the fast charging process.
  • the present application proposes a battery, comprising the separator described in the first aspect of the present application or the separator obtained by the method described in the second aspect of the present application.
  • the battery has excellent cycle performance.
  • the present application proposes an electrical device, comprising the battery described in the third aspect of the present application.
  • FIG. 1 is a schematic structural diagram of an isolation membrane according to an embodiment of the present application.
  • FIG. 2 is a schematic structural diagram of an isolation membrane according to another embodiment of the present application.
  • FIG. 3 is a schematic diagram of a battery according to an embodiment of the present application.
  • FIG. 4 is an exploded view of the battery shown in FIG. 3 according to an embodiment of the present application.
  • FIG. 5 is a schematic diagram of a battery module according to an embodiment of the present application.
  • FIG. 6 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 7 is an exploded view of the battery pack shown in FIG. 6 according to an embodiment of the present application.
  • FIG. 8 is a schematic diagram of an electrical device using a battery as a power source according to an embodiment of the present application.
  • scope disclosed in the present application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range.
  • the scope limited in this way can be to include end value or not include end value, and can be combined arbitrarily, that is, any lower limit can form a scope with any upper limit combination.
  • any lower limit can form a scope with any upper limit combination.
  • the scope of 60-120 and 80-110 is listed for a particular parameter, it is understood that the scope of 60-110 and 80-120 is also expected.
  • the minimum range value 1 and 2 listed, and if the maximum range value 3,4 and 5 are listed the following scope can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5.
  • the numerical range “ab” represents an abbreviation of any real number combination between a and b, where a and b are real numbers.
  • the numerical range "0-5" means that all real numbers between "0-5" have been listed in this document, and "0-5" is just an abbreviation of these numerical combinations.
  • a parameter is expressed as an integer ⁇ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially.
  • the method may further include step (c), which means that step (c) may be added to the method in any order.
  • the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.
  • Secondary batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields.
  • the isolation membrane disclosed in the embodiment of the present application is suitable for lithium-ion batteries and sodium-ion batteries, and the battery disclosed in the embodiment of the present application can be used in electrical equipment using the battery as a power source or various energy storage systems using the battery as an energy storage element.
  • Electrical equipment may include, but is not limited to, mobile phones, tablets, laptops, electric toys, electric tools, battery cars, electric cars, ships, spacecraft, etc.
  • electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.
  • spacecraft may include airplanes, rockets, space shuttles, and spacecraft, etc.
  • the present application provides an isolation film.
  • the isolation film 10 includes a base film 100 and a first coating 200.
  • the first coating 200 is disposed on one side of the base film 100.
  • the first coating 200 includes the dielectric material
  • the dielectric material particles have a relative dielectric constant of 1000-10000.
  • dielectric material particles refer to materials that exhibit excellent insulating properties in an electric field, and they can separate charges and store electrical energy without losing charge.
  • the isolation film 10 of the present application includes a first coating 200 of dielectric material particles having the above-mentioned relative dielectric constant, which can improve the cycle performance of a battery containing the same during a fast charging process.
  • the isolation membrane 10 of the present application includes a first coating 200 of dielectric material particles with the above-mentioned relative dielectric constant.
  • the dielectric material particles are under the action of the electric field, and the positive and negative charge centers in the material will be separated, generating a reverse electric field inside.
  • the reverse electric field generated by the dielectric material particles makes the surface of the negative electrode plate in contact with the first coating 200 of the isolation membrane 10 appear negatively charged, and thus may attract the active ions gathered on the surface of the negative electrode plate to be evenly distributed, thereby reducing the risk of active ions gathering on the surface of the negative electrode plate to generate metal dendrites, thereby improving the cycle performance of the battery containing it during the fast charging process.
  • the relative dielectric constant of the dielectric material particles is 1000-10000, such as 1000-9500, 1500-9000, 2000-8500, 2500-8000, 3000-7500, 3500-7000, 4000-6500, 4500-6000, 5000-5500, etc. In other embodiments of the present application, the relative dielectric constant of the first dielectric material particles is 1500-5000.
  • the relative dielectric constant of dielectric material particles refers to the relative dielectric constant at room temperature (25 ⁇ 5° C.), which has a well-known meaning in the art and can be tested using instruments and methods known in the art.
  • the first coating 200 of the isolation membrane 10 can be scraped off, and the obtained powder is heated to 1000°C in an oxygen-containing atmosphere and kept warm for 1 hour for sintering, and water is added to filter and separate to obtain dielectric material particles, and then the dielectric material particles are prepared into circular test samples (the sample preparation process includes: adding 40g of adhesive (the adhesive is compounded by acrylic acid (PAA) emulsion and alcohol amine plasticizer, and its decomposition temperature is less than 300°C) to 200g of the dielectric material particles to be tested, and after fully stirring, slowly adding to an automatic roller press (the roller press is a double-roll roller press, the rollers are made of stainless steel and the surface is polished; the gap between the two pairs of rollers is adjustable in the range of 0.5mm to 2
  • PAA acrylic
  • the raw material porcelain cake is then placed on a punching machine (the punching machine has a circular platen with a size of The pressure plate is made of stainless steel and has a polished surface. Ten thin circular ceramic pieces with a diameter of 11 ⁇ 1 mm are punched out under the pressure plate.
  • silver coating place the thin layer of round porcelain after debonding in step (2) on a clean and flat zirconia or alumina support plate, and use a fine brush to evenly apply silver paste on the front of the thin layer of round porcelain.
  • the silver paste is a high-temperature sintered conductive silver paste.
  • the silver paste is applied in one direction for 2-3 times, and the thickness is 80 ⁇ m to 100 ⁇ m;
  • silver burning first use a blade to gently scrape off the silver layer on the side of the thin layer of round porcelain after silver coating in step (3), and then place the thin layer of round porcelain after silver coating on the surface of the thin layer of round porcelain.
  • the volume average particle size Dv50 of the dielectric material particles is 200nm-2000nm, for example, 300nm-1900nm, 400nm-1800nm, 500nm-1700nm, 600nm-1600nm, 700nm-1500nm, 800nm-1400nm, 900nm-1300nm, 1000nm-1200nm, 1000nm-1100nm, etc.
  • the cycle performance of the battery during the fast charging process can be further improved.
  • the process by which the dielectric material particles of the above-mentioned particle size exert their performance is speculated as follows:
  • the dielectric material particles of the particle size of the present application on the one hand, can exert their excellent reverse electric field effect, and thus may attract the active ions gathered on the surface of the negative electrode plate to be evenly distributed, thereby reducing the risk of active ions gathering on the surface of the negative electrode plate to produce metal dendrites, thereby further improving the cycle performance of the battery containing it during the fast charging process.
  • the use of dielectric material particles of this particle size in the first coating 200 can avoid the dielectric material particles blocking the pores of the base film 100 and reducing the transmission of active ions.
  • the volume average particle size Dv50 of the dielectric material particles is 500nm-1500nm.
  • the volume average particle size Dv50 of the dielectric material particles refers to the particle size corresponding to when the cumulative volume distribution percentage reaches 50%.
  • the test method for the volume average particle size Dv50 of the dielectric material particles in the isolation film is as follows:
  • the isolation membrane 10 is heated to 1000° C. in an oxygen-containing atmosphere and kept at this temperature for 1 hour for sintering, and then water is added and filtered;
  • the dielectric material particles include at least one of barium titanate, lead titanate, lithium niobate, lead zirconate titanate, lead metaniobate, or lead barium lithium niobate.
  • barium titanate lead titanate
  • lithium niobate lead titanate
  • lead zirconate titanate lead metaniobate
  • lead barium lithium niobate lead barium lithium niobate
  • the dielectric material particles of the above composition can exert excellent reverse electric field effects.
  • the reverse electric field generated by the dielectric material particles makes the surface of the negative electrode plate in contact with the first coating 200 of the isolation membrane 10 appear negatively charged, and thus may attract the active ions gathered on the surface of the negative electrode plate to be evenly distributed, thereby reducing the risk of active ions gathering on the surface of the negative electrode plate to produce metal dendrites, thereby further improving the cycle performance of the battery containing it during the fast charging process.
  • the present application has no particular limitation on the type of the base film 100 , and any known porous structure base film with good chemical stability and mechanical stability can be selected.
  • the material of the base film 100 may include glass fiber, non-woven fabric, polyethylene, polypropylene or polypropylene. At least one of vinylidene fluoride.
  • the base film 100 can be a single-layer film or a multi-layer composite film, without particular limitation. When the base film is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.
  • the mass proportion of the dielectric material particles is 20%-80%, such as 25%-75%, 30%-70%, 35%-65%, 40%-60%, 45%-55%, 50%-55%, etc. Therefore, adding the above content of dielectric material particles to the first coating 200 can further improve the cycle performance of the battery containing the dielectric material particles during the fast charging process.
  • the process by which the dielectric material particles of the above content exert their performance is speculated as follows: by adding the dielectric material particles of the above content to the first coating 200, an excellent reverse electric field effect can be exerted.
  • the reverse electric field generated by the dielectric material particles makes the surface of the negative electrode sheet in contact with the first coating 200 of the isolation membrane 10 negatively charged, and thus may attract the active ions gathered on the surface of the negative electrode sheet to be evenly distributed, thereby reducing the risk of active ions gathering on the surface of the negative electrode sheet to produce metal dendrites, thereby further improving the cycle performance of the battery containing it during the fast charging process.
  • the mass of the dielectric material particles accounts for 30%-70%.
  • the method for testing the mass percentage of dielectric material particles in the first coating 200 in the isolation membrane 10 includes: scraping powder on the first coating 200 in the isolation membrane 10, and subjecting the sample to a thermal gravimetric test.
  • the test conditions are: oxygen atmosphere, heating from 25°C to 500°C, and a heating rate of 5°/min.
  • the corresponding ordinate on the thermal gravimetric curve corresponding to 500°C is the mass percentage of dielectric material particles.
  • the thickness of the first coating 200 is 0.5 ⁇ m-2 ⁇ m, for example, 0.6 ⁇ m-1.9 ⁇ m, 0.7 ⁇ m-1.8 ⁇ m, 0.8 ⁇ m-1.7 ⁇ m, 0.9 ⁇ m-1.6 ⁇ m, 1 ⁇ m-1.5 ⁇ m, 1.1 ⁇ m-1.4 ⁇ m, 1.2 ⁇ m-1.3 ⁇ m. In some other embodiments of the present application, the thickness of the first coating 200 is 0.8 ⁇ m-1.7 ⁇ m. Thus, a first coating 200 having this thickness is provided on one side of the base film 100, which can further improve the cycle performance of the battery containing it during the fast charging process.
  • the thickness test method of the first coating 200 includes: firstly, cutting the isolation film 10 to be tested into a 6mm ⁇ 6mm sample to be tested, clamping the sample to be tested with two pieces of conductive and thermally conductive copper foil, fixing the sample to be tested and the copper foil with double-sided tape, pressing with a certain 400g flat iron block for 1 hour, so that the gap between the sample to be tested and the copper foil is as small as possible, and then trimming the edges with scissors, sticking it on the sample stage with conductive glue, and the sample slightly protruding from the edge of the sample stage.
  • the sample stage is put into the sample holder and locked and fixed, the power of the IB-19500CP argon ion cross-section polisher is turned on and vacuumed to 10Pa -4 Pa, the argon flow rate is set to 0.15MPa and the voltage is set to 8KV, and the polishing time is 2 hours, the sample stage is adjusted to the swing mode to start polishing, and after the polishing is completed, the ion polishing cross-sectional morphology (CP) picture of the sample to be tested is obtained using a ZEISS Sigma300 scanning electron microscope, and the thickness of the first coating 200 can be obtained.
  • CP ion polishing cross-sectional morphology
  • the BET specific surface area of the dielectric material particles is 0.5m 2 /g-6m 2 /g, for example, 1m 2 /g-5.5m 2 /g, 1.5m 2 /g-5m 2 /g, 2m 2 /g-4.5m 2 /g, 2.5m 2 /g-4m 2 /g, 3m 2 /g-3.5m 2 /g, etc. Therefore, the use of dielectric material particles with such specific surface area in the first coating 200 can further improve the battery containing the dielectric material particles during fast charging. The cycle performance of the process.
  • the process by which the dielectric material particles of the above specific surface area exert their performance is speculated as follows:
  • the dielectric material particles of the above specific surface area range can exert excellent reverse electric field effects.
  • the reverse electric field generated by the dielectric material particles makes the surface of the negative electrode sheet in contact with the first coating 200 of the isolation film 10 negatively charged, thereby possibly attracting the active ions gathered on the surface of the negative electrode sheet to be evenly distributed, thereby reducing the risk of active ions gathering on the surface of the negative electrode sheet to generate metal dendrites, thereby further improving the cycle performance of the battery containing it during the fast charging process.
  • the BET specific surface area of the dielectric material particles is 0.8m2 /g- 4m2 /g.
  • the BET specific surface area of the dielectric material particles is a well-known meaning in the art and can be tested using instruments and methods well-known in the art.
  • the area of the cut isolation film 10 is 5cm*5cm, and then the sample is heated to 1000°C in an oxygen-containing atmosphere and kept warm for 1h for sintering, and water is added for filtration and separation to obtain dielectric material particles.
  • the filtered sample is tested using the nitrogen adsorption specific surface area analysis test method, and the BET (Brunauer Emmett Teller) method is used to calculate the nitrogen adsorption specific surface area analysis test.
  • the nitrogen adsorption specific surface area analysis test can be performed using the Tri-Star 3020 specific surface area pore size analysis tester from Micromeritics, USA.
  • the first coating 200 further includes a first binder
  • the first binder includes at least one of polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, or fluorine-containing acrylate resin.
  • the bonding performance between the first coating 200 and the base film 100 can be improved, the isolation film 10 can be prevented from falling powder during use, and the battery cycle performance can be improved.
  • the isolation film 10 further includes a second coating layer 300, which is disposed on a side of the base film 100 away from the first coating layer 200, and the second coating layer 200 includes inorganic particles.
  • the second coating layer 300 including inorganic particles can be significantly improved.
  • the inorganic particles include at least one of silica, alumina, zirconium dioxide, zinc oxide, magnesium oxide, sodium sulfate, barium sulfate, boehmite or calcium carbonate, and can be selected from at least one of silica, alumina, boehmite, zirconium dioxide or barium sulfate.
  • the volume average particle size Dv50 of the inorganic particles is 0.5 ⁇ m-2.5 ⁇ m, for example, 0.8 ⁇ m-2.3 ⁇ m, 1 ⁇ m-2.1 ⁇ m, 1.2 ⁇ m-2 ⁇ m, 1.5 ⁇ m-1.8 ⁇ m, 1.6 ⁇ m-1.7 ⁇ m.
  • the volume average particle size Dv50 of the inorganic particles is 0.8 ⁇ m-2.3 ⁇ m.
  • the volume average particle size Dv50 of the inorganic particles refers to the volume average particle size when the cumulative volume distribution percentage reaches 50%.
  • the corresponding particle size, the test method of the volume average particle size Dv50 of the inorganic particles in the isolation film is as follows:
  • the sample stage into the sample holder and lock it, turn on the power of the IB-19500CP argon ion cross-section polisher and evacuate it to 10Pa -4 Pa, set the argon flow rate to 0.15MPa and the voltage to 8KV, and the polishing time to 2 hours, adjust the sample stage to the swing mode to start polishing, and after polishing, use a ZEISS Sigma300 scanning electron microscope to obtain the ion polishing cross-sectional morphology (CP) picture of the sample to be tested, and the thickness of the second coating 300 can be obtained.
  • CP ion polishing cross-sectional morphology
  • the isolation membrane of the present application includes a first coating layer of dielectric material particles with the above-mentioned relative dielectric constant.
  • the dielectric material particles are subjected to the action of an electric field, and the positive and negative charge centers in the material are separated, generating a reverse electric field inside.
  • the reverse electric field generated by the dielectric material particles makes the surface of the negative electrode plate in contact with the first coating layer of the isolation membrane appear negatively charged, and thus may attract the active ions gathered on the surface of the negative electrode plate to be evenly distributed, thereby reducing the risk of active ions gathering on the surface of the negative electrode plate to generate metal dendrites, thereby improving the cycle performance of the battery containing it during the fast charging process.
  • dielectric material particles are mixed with a first binder and a solvent such as deionized water to prepare a first slurry, the first slurry is then coated on one side of the base film, and an isolation film having a first coating is obtained after drying.
  • dielectric material particles are mixed with a first binder and a solvent such as deionized water to prepare a first slurry, and then the first slurry is coated on one side of the base film, and a first coating layer including dielectric material particles is formed on one side of the base film after drying, and then the isolation film is turned over, and a second slurry including inorganic particles, a second binder and a solvent deionized water is coated on the side of the base film away from the first coating layer, and a second coating layer containing inorganic particles is formed on the other side of the base film after drying.
  • a solvent such as deionized water
  • the present application proposes a battery, wherein the battery comprises the isolation membrane described in the first aspect of the present application or the isolation membrane obtained by the method described in the second aspect of the present application.
  • a battery is a battery that can be used again by recharging the active materials after discharge.
  • a battery typically includes a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte.
  • active ions are embedded and removed back and forth between the positive electrode sheet and the negative electrode sheet.
  • the separator is arranged between the positive electrode sheet and the negative electrode sheet (when the positive electrode sheet, the separator and the negative electrode sheet are stacked, the first coating on the separator is in contact with the negative electrode sheet) to play an isolating role.
  • the electrolyte plays the role of conducting ions between the positive electrode sheet and the negative electrode sheet.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector, wherein the positive electrode active material layer includes a positive electrode active material.
  • the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material layer is disposed on any one or both of the two facing surfaces of the positive electrode current collector.
  • the positive electrode current collector may be a metal foil or a composite current collector.
  • aluminum foil may be used as the metal foil.
  • the composite current collector may include a polymer material base layer and a The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene terephthalate
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the positive electrode active material may be a positive electrode active material for a battery known in the art.
  • the positive electrode active material may be a positive electrode active material for a lithium-ion battery known in the art.
  • the positive electrode active material may include at least one of the following materials: an olivine-structured lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other traditional 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.
  • lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO 2 ), lithium nickel oxide (such as LiNiO 2 ), lithium manganese oxide (such as LiMnO 2 , LiMn 2 O 4 ), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O 2 (also referred to as NCM 811 ), and LiNi 0.8 Co 0.2 Mn 0.2 O 2 (also referred to as NCM 811 ), lithium
  • lithium phosphates containing olivine structures may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO 4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate or a composite material of lithium iron manganese phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 (also referred to as LFP)
  • LiMnPO 4 lithium manganese phosphate
  • the positive electrode active material may be a positive electrode active material for a sodium ion battery known in the art.
  • the positive electrode active material may include but is not limited to at least one of a layered transition metal oxide, a polyanion compound, or a Prussian blue analog.
  • layered transition metal oxides examples include:
  • M 2 comprises at least one of Li, Mg, Al, Ca, Ti, Fe, Cu, Zn or Ba, and 0 ⁇ z ⁇ 0.1;
  • polyanionic compound examples include:
  • A1fM3g ( PO4 ) iOjX13 -j wherein A1 comprises at least one of H, Li, Na, K or NH4 , M3 comprises at least one of Ti, Cr, Mn, Fe, Co, Ni, V, Cu or Zn, X1 is at least one of F, Cl or Br , 0 ⁇ f ⁇ 4, 0 ⁇ g ⁇ 2, 1 ⁇ i ⁇ 3, 0 ⁇ j ⁇ 2 ;
  • M 4 comprises at least one of Mn, Fe, Co, Ni, Cu or Zn, X 2 is at least one of F, Cl or Br, 0 ⁇ n ⁇ 2;
  • M 5 comprises at least one of Mn, Fe, Co, Ni, Cu or Zn, 0 ⁇ p ⁇ 2, 0 ⁇ q ⁇ 2;
  • Prussian blue analogs examples include:
  • A includes at least one of H + , Li + , Na + , K + , NH4 + , Rb + , Cs + , Fr + , Be2+ , Mg2 + , Ca2+, Sr2 + , Ba2 + or Ra2 + , and M6 and M7 each independently include at least one of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn or W cations.
  • the battery will be accompanied by the deintercalation and consumption of Li or Na during the charge and discharge process, and the molar content of Li or Na is different when the battery is discharged to different states.
  • the molar content of Li or Na is the initial state of the material, that is, the state before feeding.
  • the positive electrode active material is used in the battery system, and the molar content of Li or Na will change after charge and discharge cycles.
  • the molar content of oxygen is only a theoretical value. The release of oxygen from the lattice will cause the molar content of oxygen to change, and the actual molar content of oxygen will fluctuate.
  • the positive electrode active material layer may further optionally include a binder.
  • the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, or fluorine-containing acrylate resin.
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • PTFE polytetrafluoroethylene
  • vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer
  • the mass proportion of the binder is 0.5%-3%, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, etc.
  • the positive electrode active material layer may further optionally include a conductive agent.
  • the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, or carbon nanofibers.
  • the mass proportion of the conductive agent is 0.8%-4%, for example, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, etc.
  • the positive electrode sheet can be prepared in the following manner: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.
  • a solvent such as N-methylpyrrolidone
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.
  • the negative electrode active material layer includes a negative electrode active material.
  • the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material layer is disposed on either or both of the two facing surfaces of the negative electrode current collector.
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • the metal foil copper foil may be used.
  • the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material 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 material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene terephthalate
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative electrode active material may adopt the negative electrode active material for the battery known in the art.
  • 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 titanates, etc.
  • the silicon-based material may include at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites or silicon alloys.
  • the tin-based material may include at least one of elemental tin, tin oxide compounds or tin alloys.
  • the titanate uses lithium titanate; when the battery is a sodium-ion battery, the titanate uses sodium titanate.
  • the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries can also be used. These negative electrode active materials can be used alone or in combination of two or more.
  • the negative electrode active material layer may further optionally include a binder.
  • the binder may include 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), or carboxymethyl chitosan (CMCS).
  • the negative electrode active material layer may further include a conductive agent, which may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, or carbon nanofibers.
  • a conductive agent which may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, or carbon nanofibers.
  • the negative electrode active material layer may further optionally include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).
  • a thickener eg, sodium carboxymethyl cellulose (CMC-Na)
  • the negative electrode sheet can be prepared in the following manner: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.
  • a solvent such as deionized water
  • a battery includes a positive electrode, a negative electrode, an electrolyte, and a separator.
  • active ions are embedded and released back and forth between the positive electrode and the negative electrode.
  • the electrolyte plays the role of conducting ions between the positive electrode and the negative electrode.
  • the separator is set between the positive electrode and the negative electrode, mainly to prevent the positive and negative electrodes from short-circuiting. It can also allow ions to pass through.
  • the present application has no specific restrictions on the type of electrolyte, which can be selected according to needs.
  • the electrolyte can be liquid, gel or all-solid.
  • the electrolyte is an electrolyte solution, which includes an electrolyte salt and a solvent.
  • the electrolyte salt may include 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 difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate or lithium tetrafluorooxalatophosphate.
  • the electrolyte sodium salt may include at least one of sodium hexafluorophosphate, sodium difluorooxalatoborate, sodium tetrafluoroborate, sodium bisoxalatoborate, sodium perchlorate, sodium hexafluoroarsenate, sodium bis(fluorosulfonyl)imide, sodium trifluoromethylsulfonate or sodium bis(trifluoromethylsulfonyl)imide.
  • the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane sulfone, dimethyl sulfone, methyl ethyl sulfone or diethyl sulfone.
  • the electrolyte may further include additives.
  • the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.
  • the positive electrode sheet, the negative electrode sheet, and the separator may be formed into an electrode assembly by a winding process or a lamination process.
  • the outer packaging of the secondary battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.
  • the outer packaging of the secondary battery may also be a soft package, such as a bag-type soft package.
  • the material of the soft package may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.
  • FIG3 is a battery cell 1 of a square structure as an example.
  • the outer package may include a shell 11 and a cover plate 13.
  • the shell 11 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity.
  • the shell 11 has an opening connected to the receiving cavity, and the cover plate 13 can be covered on the opening to close the receiving cavity.
  • the positive electrode sheet, the negative electrode sheet and the isolation film can form an electrode assembly 12 through a winding process or a lamination process.
  • the electrode assembly 12 is encapsulated in the receiving cavity.
  • the electrolyte is infiltrated in the electrode assembly 12.
  • the number of electrode assemblies 12 contained in the battery cell 1 can be one or more, and those skilled in the art can select according to specific actual needs.
  • the batteries can be assembled into a battery module, and the number of batteries contained in the battery module can be one or more, the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.
  • FIG5 is a battery module 2 as an example.
  • a plurality of battery cells 1 may be arranged in sequence along the length direction of the battery module 2. Of course, they may also be arranged in any other manner. Further, the plurality of battery cells 1 may be fixed by fasteners.
  • the battery module 2 may further include a housing having a receiving space, and the plurality of battery cells 1 are received in the receiving space.
  • the battery modules described above may also be assembled into a battery pack.
  • the battery pack may contain one or more battery modules, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery pack.
  • FIG6 and FIG7 are battery packs 3 as an example.
  • the battery pack 3 may include a battery box and a plurality of battery modules 2 disposed in the battery box.
  • the battery box includes an upper box body 31 and a lower box body 32, and the upper box body 31 can be covered on the lower box body 32 to form a closed space for accommodating the battery modules 2.
  • the plurality of battery modules 2 can be arranged in the battery box in any manner.
  • the present application also provides an electrical device, which includes at least one of the secondary battery, battery module, or battery pack provided in the present application.
  • the secondary battery, battery module, or battery pack can be used as a power source for the electrical device, and can also be used as an energy storage unit for the electrical device.
  • the electrical device may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as 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., but are not limited thereto.
  • a secondary battery, a battery module or a battery pack may be selected according to its usage requirements.
  • FIG8 is an example of an electric device.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • a battery pack or a battery module may be used.
  • the device may be a mobile phone, a tablet computer, a notebook computer, etc.
  • the device is usually required to be light and thin, and a battery may be used as a power source.
  • the positive electrode active material lithium nickel cobalt manganese oxide (NCM523, i.e. LiNi 0.5 Co 0.2 Mn 0.3 O 2 ), the binder polyvinylidene fluoride PVDF, and the conductive agent acetylene black were mixed in a weight ratio of 98:1:1, and N-methylpyrrolidone (NMP) was added as The solvent is added, and the slurry is stirred under vacuum until it is uniform to obtain positive electrode slurry, and then the obtained positive electrode slurry is coated on the double-side surface of 13 ⁇ m aluminum foil with a scraper at a surface density of 14 mg/ cm2 , and then dried at 140°C, cold pressed, and cut to obtain positive electrode sheets.
  • NMP N-methylpyrrolidone
  • the negative electrode active material artificial graphite, conductive agent acetylene black, composite binder SBR (styrene butadiene rubber), and dispersant sodium carboxymethyl cellulose (CMC-Na) were dissolved in deionized water at a weight ratio of 97:1:1:1, stirred and mixed evenly to prepare a negative electrode slurry, and the negative electrode slurry was coated on both sides of a 5 ⁇ m copper foil with a scraper at a surface density of 15.4mg/ cm2 . After drying, cold pressing, and slitting, the negative electrode sheet was obtained.
  • organic solvents ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed at a volume ratio of 3:7 to obtain an organic solvent, LiPF 6 was dissolved in the above solvent, and stirred to obtain an electrolyte with a concentration of 1 mol/L.
  • the dielectric material particles of barium titanate are mixed with the adhesive polyvinylidene fluoride and deionized water to obtain a first slurry, which is coated on one side of the PE base film and then dried to remove moisture to obtain an isolation film (one side of the isolation film has a first coating layer including dielectric material particles, and the thickness of the first coating layer is 1.5 ⁇ m).
  • the positive electrode sheet, the separator, and the negative electrode sheet are stacked in order (the first coating layer including dielectric material particles on the separator is close to the negative electrode sheet), so that the separator is located between the positive and negative electrodes to play a role of isolation, and then wound to obtain a bare cell.
  • the bare cell is placed in an outer package, injected with the above electrolyte and packaged to obtain a lithium-ion battery.
  • the preparation method of the lithium ion battery of Examples 14-21 and Comparative Example 3 is the same as that of Example 1, except that the process of preparing the isolation membrane is different, specifically comprising: mixing the dielectric material particles barium titanate with the adhesive polyvinylidene fluoride and deionized water to obtain a first slurry, mixing boehmite with the adhesive polyvinylidene fluoride and deionized water to obtain a second slurry, and then coating the second slurry on one side of the PE base film, drying (forming a first coating layer including a dielectric material on one side of the isolation membrane, and the first coating layer has a thickness of 1.5 ⁇ m), coating the second slurry on the other side of the PE base film, and then drying (forming a second coating layer including inorganic particles on the other side of the isolation membrane, and the second coating layer has a thickness of 1.5 ⁇ m), cutting, and the isolation membrane can be obtained, as shown in Table 2.
  • the lithium deposition and cycle performance of the batteries of Examples 1-13 and Comparative Examples 1-3 were characterized, and the characterization results are shown in Table 3.
  • the lithium deposition and cycle performance of the batteries of Examples 14-21 and the high temperature resistance of the isolation membrane were characterized, and the characterization results are shown in Table 5.
  • the battery was charged to 4.4 V at 4C, allowed to stand for 5 min, and then discharged to 2.8 V at 1C and allowed to stand for 5 min.
  • the above charge and discharge process was cycled for 500 times, and then the negative electrode was disassembled.
  • the surface of the disassembled negative electrode was scanned under vacuum conditions using electron backscatter diffraction (EBSD) technology (the scanning angle of the scanning electron microscope (SEM) used was 70 degrees), and the lithium deposition area signal and the non-lithium deposition area signal were collected respectively.
  • EBSD electron backscatter diffraction
  • SEM scanning electron microscope
  • the first coating layer of the isolation membrane of the battery of Example 1-13 contains dielectric material particles with a relative dielectric constant of 1000-10000; no dielectric material particles are added to the isolation membrane of the battery of Comparative Example 1, and the dielectric material particles of the first coating layer in the isolation membrane of the battery of Comparative Example 2 are aluminum oxide particles with a relative dielectric constant of 70. It can be seen from the data in Table 3 that the lithium plating area of the negative electrode sheet of the battery of Example 1-13 after cycle disassembly is significantly smaller than that of Comparative Example 1-2, and the cycle performance of the battery of Example 1-13 is also higher than that of Comparative Example 1-2.
  • the first coating layer of the isolation membrane of the battery in Example 14-21 contains dielectric material particles with a relative dielectric constant of 1000-10000, and the second coating layer contains inorganic particles; the first coating layer of the battery in Comparative Example 3 uses aluminum oxide particles with a relative dielectric constant of 70, and the second coating layer contains inorganic particles. It can be seen from the data in Table 5 that the lithium plating area of the negative electrode plate of the battery in Example 14-21 after cycle disassembly is significantly smaller than that in Comparative Example 3, and the cycle performance of the battery in Example 14-21 is also higher than that in Comparative Example 3. At the same time, the isolation membrane of the battery in Example 14-21 has a higher high temperature resistance.
  • the first coating layer in the isolation membrane of the present application uses dielectric material particles with a relative dielectric constant of 1000-10000 and inorganic particles in the second coating layer, which can not only reduce the risk of lithium plating during the fast charging process, but also improve the cycle performance of the battery during the fast charging process, and can also improve the high temperature resistance of the isolation membrane.

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Abstract

一种隔离膜及其制备方法、电池和用电装置，所述隔离膜包括基膜和第一涂层，所述第一涂层设在所述基膜的一侧，所述第一涂层包括介电材料颗粒，所述介电材料颗粒的相对介电常数为1000-10000。隔离膜包括上述相对介电常数的介电材料颗粒的第一涂层，可以提高含有其的电池在快充过程的循环性能。

Description

隔离膜及其制备方法、电池和用电装置
优先权信息
本申请请求2024年01月03日向中国国家知识产权局提交的专利申请202410012603.7的优先权和权益，并且通过参照将其全文并入此处。
技术领域
本申请属于电池领域，具体涉及一种隔离膜及其制备方法、电池和用电装置。
背景技术
二次电池广泛应用于水力、火力、风力和太阳能电站等储能电源系统，以及电动工具、电动自行车、电动摩托车、电动汽车、军事装备、航空航天等多个领域。随着电池应用范围越来越广泛，对二次电池性能的要求也逐渐严苛，比如要求其具有快充能力。然而电池快充过程中负极极片的表面易产生金属枝晶，导致电池循环性能降低。
发明内容
鉴于背景技术中存在的技术问题，本申请提供一种隔离膜，旨在提高含有其的电池在快充过程的循环性能。
为了实现上述目的，本申请第一个方面提出了一种隔离膜，所述隔离膜包括：
基膜；
第一涂层，所述第一涂层设在所述基膜的一侧，所述第一涂层包括介电材料颗粒，所述介电材料颗粒的相对介电常数为1000-10000。
本申请至少包括如下所述的有益效果：本申请的隔离膜包括上述相对介电常数的介电材料颗粒的第一涂层，可以提高含有其的电池在快充过程的循环性能。
在一些实施方式中，所述介电材料颗粒的相对介电常数为1500-5000。由此，可以进一步提高电池在快充过程的循环性能。
在一些实施方式中，所述介电材料颗粒的体积平均粒径Dv50为200nm-2000nm，可选为500nm-1500nm。由此，可以提高电池在快充过程的循环性能。
在一些实施方式中，所述介电材料颗粒包括钛酸钡、钛酸铅、铌酸锂、锆钛酸铅、偏铌酸铅或铌酸铅钡锂中的至少一种。由此，可以提高电池在快充过程的循环性能。
在一些实施方式中，基于所述第一涂层的总质量，所述介电材料颗粒的质量占比为20％-80％，可选为30％-70％。由此，可以提高电池在快充过程的循环性能。
在一些实施方式中，所述第一涂层的厚度为0.5μm-2μm，可选为0.8μm-1.7μm。由此，可以提高电池在快充过程的循环性能。
在一些实施方式中，所述介电材料颗粒的BET比表面积为0.5m2/g-6m2/g，可选为0.8m2/g-4m2/g。由此，可以提高电池在快充过程的循环性能。
在一些实施方式中，所述第一涂层还包括第一粘结剂。由此，可以提高第一涂层与基膜的粘接性能。
在一些实施方式中，所述第一粘结剂包括聚四氟乙烯、聚三氟氯乙烯、聚氟乙烯、聚偏二氟乙烯、聚乙烯、聚丙烯、聚丙烯腈、聚环氧乙烷、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物或含氟丙烯酸酯树脂中的至少一种。由此，可以提高第一涂层与基膜的粘接性能。
在一些实施方式中，所述隔离膜还包括第二涂层，所述第二涂层设在所述基膜上远离所述第一涂层的一侧，所述第二涂层包括无机颗粒。由此，可以提高隔离膜的耐高温性能。
在一些实施方式中，所述无机颗粒包括二氧化硅、氧化铝、二氧化锆、氧化锌、氧化镁、硫酸钠、硫酸钡、勃姆石或碳酸钙中的至少之一，可选为二氧化硅、氧化铝、勃姆石、二氧化锆或硫酸钡中的至少之一。由此，可以提高隔离膜的耐高温性能。
在一些实施方式中，所述无机颗粒的体积平均粒径Dv50为0.5μm-2.5μm，可选为0.8μm-2.3μm。由此，可以提高隔离膜的耐高温性能。
在一些实施方式中，所述第二涂层的厚度为0.5μm-4μm，可选为1μm-2μm。由此，可以提高隔离膜的耐高温性能。
在一些实施方式中，基于所述第二涂层的总质量，所述无机颗粒的质量占比为30％-70％，可选为40％-60％。由此，可以提高隔离膜的耐高温性能。
在一些实施方式中，所述第二涂层包括第二粘结剂。由此，可以提高第二涂层与基膜的粘接性能。
在本申请第二方面，本申请提出了一种制备隔离膜的方法，包括：在基膜的一侧形成包括介电材料颗粒的第一涂层，得到隔离膜，所述介电材料颗粒的相对介电常数为1000-10000。
由此，采用该方法所得隔离膜的电池在快充过程具有优异的循环性能。
在本申请第三方面，本申请提出了一种电池，包括本申请第一方面所述的隔离膜或本申请第二方面所述的方法得到的隔离膜。由此，该电池具有优异的循环性能。
在本申请第四方面，本申请提出了一种用电装置，包括本申请第三方面所述的电池。
本申请的附加方面和优点将在下面的描述中部分给出，部分将从下面的描述中变得明显，或通过本申请的实践了解到。
附图说明
通过阅读对下文优选实施方式的详细描述，各种其他的优点和益处对于本领域普通技术人员将变得清楚明了。附图仅用于示出优选实施方式的目的，而并不认为是对本申请的限制。而且在全部附图中，用相同的附图标号表示相同的部件。在附图中：
图1是本申请一实施方式的隔离膜的结构示意图。
图2是本申请再一实施方式的隔离膜的结构示意图。
图3是本申请一实施方式的电池的示意图。
图4是图3所示的本申请一实施方式的电池的分解图。
图5是本申请一实施方式的电池模块的示意图。
图6是本申请一实施方式的电池包的示意图。
图7是图6所示的本申请一实施方式的电池包的分解图。
图8是本申请一实施方式的电池用作电源的用电装置的示意图。
附图标记说明：
10隔离膜；100基膜；200第一涂层；300第二涂层；1电池单体；11壳体；12电极组件；13盖板；2电池模块；3电池包；31上箱体；32下箱体。
具体实施方式
下面对本申请技术方案的实施例进行详细的描述。以下实施例仅用于更加清楚地说明本申请的技术方案，因此只作为示例，而不能以此来限制本申请的保护范围。
在本文中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。本领域技术人员显式地和隐式地理解的是，本文所描述的实施例可以与其它实施例相结合。
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110的范围，理解为60-110和80-120的范围也是预料到的。此外，如果列出的最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。 在本申请中，除非有其他说明，数值范围“a-b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有步骤可以顺序进行，也可以随机进行，优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，所述提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。
目前，从市场形势的发展来看，二次电池的应用越加广泛。二次电池不仅被应用于水力、火力、风力和太阳能电站等储能电源系统，而且还被广泛应用于电动自行车、电动摩托车、电动汽车等电动交通工具，以及军事装备和航空航天等多个领域。
随着二次电池应用范围越来越广泛，对二次电池性能的要求也逐渐严苛，比如要求其具有快充能力。目前二次电池在快速充电过程中，溶剂化的活性离子去溶剂化速率和在活性离子SEI膜中的扩散速率影响着电池的快充性能，尤其是在大电流充电过程中，负极活性材料体相和表相的活性离子浓度差会导致局部的活性离子浓度上升，当活性离子在负极活性材料表面突破成核壁垒时，会产生金属枝晶，由于金属优异的导电性，活性离子会优先在枝晶附近汇集，并还原形成金属枝晶，这些金属析锂可能绕过隔离膜与正极形成微短路，造成诸如电池存储、自放电、漏电流等问题，甚至会刺穿隔离膜，导致短路等严重问题。
本申请实施例公开的隔离膜适用于锂离子电池和钠离子电池，并且本申请实施例公开的电池可以用于使用电池作为电源的用电设备或者使用电池作为储能元件的各种储能系统。用电设备可以包括但不限于手机、平板、笔记本电脑、电动玩具、电动工具、电瓶车、电动汽车、轮船、航天器等等。其中，电动玩具可以包括固定式或移动式的电动玩具，例如，游戏机、电动汽车玩具、电动轮船玩具和电动飞机玩具等等，航天器可以包括飞机、火箭、航天飞机和宇宙飞船等等。
本申请第一方面提出了一种隔离膜，参考图1，所述隔离膜10包括基膜100和第一涂层200，所述第一涂层200设在所述基膜100的一侧，所述第一涂层200包括所述介电材 料颗粒，所述介电材料颗粒的相对介电常数为1000-10000。
本申请中，“介电材料颗粒”是指在电场中表现出极好绝缘性质的材料，它们可以将电荷分离并存储电能，而不会流失电荷的一类物质。
本申请的隔离膜10包括上述相对介电常数的介电材料颗粒的第一涂层200，可以提高含有其的电池在快充过程的循环性能。
上述介电材料颗粒发挥其性能的过程推测如下：本申请的隔离膜10包括上述相对介电常数的介电材料颗粒的第一涂层200，含有该隔离膜10的电池在充电过程中，介电材料颗粒在电场作用下，材料中的正负电荷中心会发生分离，在内部产生反电场，该介电材料颗粒产生的反电场使得与隔离膜10的第一涂层200接触的负极极片表面显负电，因此可能会吸引负极极片表面聚集的活性离子均匀分布，从而降低活性离子在负极极片表面聚集而产生金属枝晶的风险，进而提高含有其的电池在快充过程的循环性能。
在本申请一些实施方式中，所述介电材料颗粒的相对介电常数为1000-10000，例如1000-9500，1500-9000，2000-8500，2500-8000，3000-7500，3500-7000，4000-6500，4500-6000，5000-5500等。在本申请另一些实施方式中，所述第一介电材料颗粒的相对介电常数为1500-5000。
在本申请中，介电材料颗粒的相对介电常数是指室温(25±5℃)下的相对介电常数，其具有本领域公知的含义，可以用本领域已知的仪器及方法进行测试。例如可以将隔离膜10的第一涂层200刮粉，获得的粉料在含氧气氛下升温至1000℃并保温1h进行烧结，加水过滤分离得到介电材料颗粒，然后将介电材料颗粒制备成圆形试样(制样过程包括：向200g待测介电材料颗粒中加入40g粘合剂(所述的粘合剂由丙烯酸(PAA)乳液和醇胺类增塑剂复配而成，其分解温度小于300℃)，充分搅拌均匀后，缓慢加入自动辊压机(所述的辊压机为对辊式辊压机，辊轮为不锈钢材质，表面抛光处理；两个对辊之间的间隙在0.5mm～2mm范围内可调)，辊压成厚度为1mm±0.15mm的生料瓷饼，并以表面无色差，断面均匀、无明显分层为合格；然后将生料瓷饼放在冲片机(冲片机的压盘为圆形，尺寸为压盘为不锈钢材质，表面抛光处理)的压盘下，冲制成10个直径为11±1mm的薄层圆形瓷片；(2)排胶：将步骤(1)得到的薄层圆形瓷片放在洁净平整的氧化锆或氧化铝承烧板上，连同承烧板一起放入马弗炉，采用0.3℃/min的升温速率、升温到300℃后保温6h的进行排胶；正面排胶结束后，取出薄层圆形瓷片，更换为背面朝上，重复上述操作为背面排胶；(3)涂银：将步骤(2)排胶后的薄层圆形瓷片放在洁净平整的氧化锆或氧化铝承烧板上，使用细毛刷将银浆均匀的涂刷在薄层圆形瓷片的正面，所述的银浆为高温烧结型导电银浆，银浆涂刷采取单向涂刷2-3遍，厚度为80μm～100μm；(4)烧银：先把步骤(3)涂银后的薄层圆形瓷片的侧面沾有的银层用刀片轻轻刮掉，再将涂银后的薄层圆形瓷片 连同承烧板一起放入马弗炉中，采用5℃/min的升温速率、升温到800℃后保温2h的参数进行烧银，正面烧银完成后，取出薄层圆形瓷片和承烧板，重复步骤(3)和步骤(4)对背面进行烧银)后，采用LCR测试仪测试电容量C并根据公式：相对介电常数ε＝(C×d)/(ε0×A)计算得到。C表示电容量，单位为法拉(F)；d表示试样厚度，单位为cm；A表示试样面积，单位为cm2；ε0表示真空介电常数，ε0＝8.854×10-14F/cm。在本申请中，测试条件可以为1KHz、1.0V、25±5℃。测试标准可依据GB/T 11297.11-2015。
在本申请一些实施方式中，所述介电材料颗粒的体积平均粒径Dv50为200nm-2000nm，例如300nm-1900nm，400nm-1800nm，500nm-1700nm，600nm-1600nm，700nm-1500nm，800nm-1400nm，900nm-1300nm，1000nm-1200nm，1000nm-1100nm等。由此，可以进一步提高电池在快充过程的循环性能。
上述粒径的介电材料颗粒发挥其性能的过程推测如下：本申请粒径的介电材料颗粒，一方面可以发挥其优异的反电场作用，因此可能会吸引负极极片表面聚集的活性离子均匀分布，从而降低活性离子在负极极片表面聚集而产生金属枝晶的风险，进而进一步提高含有其的电池在快充过程的循环性能。再一方面，第一涂层200中采用该粒径的介电材料颗粒，可以避免介电材料颗粒对基膜100堵孔而降低活性离子传输。在本申请另一些实施方式中，所述介电材料颗粒的体积平均粒径Dv50为500nm-1500nm。
本申请中，所述介电材料颗粒的体积平均粒径Dv50是指累计体积分布百分数达到50％时所对应的粒径，所述隔离膜中介电材料颗粒的体积平均粒径Dv50的测试方法如下：
(1)将隔离膜10在含氧气氛下升温至1000℃并保温1h进行烧结，然后加水过滤；
(2)参照标准GB/T 19077-2016，使用激光粒度分析仪(例如Malvern Master Size 3000)对过滤的物质即介电材料颗粒测试其体积平均粒径Dv50。
在本申请一些实施方式中，所述介电材料颗粒包括钛酸钡、钛酸铅、铌酸锂、锆钛酸铅、偏铌酸铅或铌酸铅钡锂中的至少一种。由此，该类介电材料颗粒可以进一步提高含有其的电池在快充过程的循环性能。
上述组成的介电材料颗粒发挥其性能的过程推测如下：上述组成的介电材料颗粒可以发挥优异的反电场作用，该介电材料颗粒产生的反电场使得与隔离膜10的第一涂层200接触的负极极片表面显负电，因此可能会吸引负极极片表面聚集的活性离子均匀分布，从而降低活性离子在负极极片表面聚集而产生金属枝晶的风险，进而进一步提高含有其的电池在快充过程的循环性能。
本申请对基膜100的种类没有特别的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构基膜。
在一些实施方式中，基膜100的材质可包括玻璃纤维、无纺布、聚乙烯、聚丙烯或聚 偏二氟乙烯中的至少一种。基膜100可以是单层薄膜，也可以是多层复合薄膜，没有特别限制。在基膜为多层复合薄膜时，各层的材料可以相同或不同，没有特别限制。
在本申请一些实施方式中，基于所述第一涂层200的总质量，所述介电材料颗粒的质量占比为20％-80％，例如25％-75％，30％-70％，35％-65％，40％-60％，45％-55％，50％-55％等。由此，在第一涂层200中加入上述含量的介电材料颗粒可以进一步提高含有其的电池在快充过程的循环性能。
上述含量的介电材料颗粒发挥其性能的过程推测如下：通过在第一涂层200中加入上述含量的介电材料颗粒，可以发挥优异的反电场作用，该介电材料颗粒产生的反电场使得与隔离膜10的第一涂层200接触的负极极片表面显负电，因此可能会吸引负极极片表面聚集的活性离子均匀分布，从而降低活性离子在负极极片表面聚集而产生金属枝晶的风险，进而进一步提高含有其的电池在快充过程的循环性能。在本申请另一些实施方式中，基于所述第一涂层200的总质量，所述介电材料颗粒的质量占比为30％-70％。
本申请中，所述隔离膜10中第一涂层200中介电材料颗粒的质量占比测试方法包括：对隔离膜10中第一涂层200进行刮粉，将样品进行热失重测试，测试条件：氧气气氛，从25℃升温至500℃，升温速率为5°/min，500℃对应的热失重曲线(热失重(TG)曲线，其纵坐标为重量百分比，横坐标为温度)上对应的纵坐标即为介电材料颗粒的质量占比。
在本申请一些实施方式中，所述第一涂层200的厚度为0.5μm-2μm，例如0.6μm-1.9μm，0.7μm-1.8μm，0.8μm-1.7μm，0.9μm-1.6μm，1μm-1.5μm，1.1μm-1.4μm，1.2μm-1.3μm。在本申请另一些实施方式中，所述第一涂层200的厚度为0.8μm-1.7μm。由此，在基膜100的一侧设置包括该厚度的第一涂层200，可以进一步提高含有其的电池在快充过程的循环性能。
本申请，所述第一涂层200的厚度测试方法包括：首先将待测隔离膜10裁成6mm×6mm的待测样品，用两片导电导热的铜箔将待测样品夹住，将待测样品与铜箔之间用双面胶粘住固定，用一定400g平整铁块压1小时，使待测样品与铜箔间缝隙越小越好，然后用剪刀将边缘剪齐，粘在具有导电胶的样品台上，样品略突出样品台边缘即可。然后将样品台装进样品架上锁好固定，打开IB-19500CP氩离子截面抛光仪电源并抽真空至10Pa-4Pa，设置氩气流量为0.15MPa和电压为8KV，以及抛光时间2小时，调整样品台为摇摆模式开始抛光，抛光结束后，使用ZEISS Sigma300扫描电子显微镜得到待测样品的离子抛光断面形貌(CP)图片，即可得出第一涂层200的厚度。
在本申请一些实施方式中，所述介电材料颗粒的BET比表面积为0.5m2/g-6m2/g，例如1m2/g-5.5m2/g，1.5m2/g-5m2/g，2m2/g-4.5m2/g，2.5m2/g-4m2/g，3m2/g-3.5m2/g等。由此，在第一涂层200中采用该比表面积的介电材料颗粒，可以进一步提高含有其的电池在快充过 程的循环性能。
上述比表面积的介电材料颗粒发挥其性能的过程推测如下：上述比表面积范围的介电材料颗粒，其可以发挥优异的反电场作用，该介电材料颗粒产生的反电场使得与隔离膜10的第一涂层200接触的负极极片表面显负电，因此可能会吸引负极极片表面聚集的活性离子均匀分布，从而降低活性离子在负极极片表面聚集而产生金属枝晶的风险，进而进一步提高含有其的电池在快充过程的循环性能。在本申请另一些实施方式中，所述介电材料颗粒的BET比表面积为0.8m2/g-4m2/g。
本申请中，所述介电材料颗粒的BET比表面积为本领域公知的含义，可以用本领域公知的仪器及方法进行测试。例如先对裁切隔离膜10面积为5cm*5cm，然后将取样在含氧气氛下升温至1000℃并保温1h进行烧结，加水过滤分离得到介电材料颗粒。然后参照GB/T19587-2017，采用氮气吸附比表面积分析测试方法测试过滤样品，并用BET(BrunauerEmmett Teller)法计算得出，氮气吸附比表面积分析测试可以通过美国Micromeritics公司的Tri-Star 3020型比表面积孔径分析测试仪进行。
在本申请一些实施方式中，所述第一涂层200还包括第一粘结剂，作为示例，所述第一粘结剂包括聚四氟乙烯、聚三氟氯乙烯、聚氟乙烯、聚偏二氟乙烯、聚乙烯、聚丙烯、聚丙烯腈、聚环氧乙烷、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物或含氟丙烯酸酯树脂中的至少一种。由此，可以提高第一涂层200与基膜100的粘结性能，避免隔离膜10在使用过程中掉粉，提高电池循环性能。
在本申请一些实施方式中，参考图2，所述隔离膜10还包括第二涂层300，所述第二涂层300设在所述基膜100上远离所述第一涂层200的一侧，所述第二涂层200包括无机颗粒。由此，通过在基膜100上远离所述含有介电材料颗粒的第一涂层200的一侧设置包括无机颗粒的第二涂层300，可以显著提高隔离膜10的耐高温性能。
作为示例，所述无机颗粒包括二氧化硅、氧化铝、二氧化锆、氧化锌、氧化镁、硫酸钠、硫酸钡、勃姆石或碳酸钙中的至少之一，可选为二氧化硅、氧化铝、勃姆石、二氧化锆或硫酸钡中的至少之一。
在本申请一些实施方式中，所述无机颗粒的体积平均粒径Dv50为0.5μm-2.5μm，例如0.8μm-2.3μm，1μm-2.1μm，1.2μm-2μm，1.5μm-1.8μm，1.6μm-1.7μm。由此，通过在第二涂层300中加入上述粒径的无机颗粒，不仅可以提高隔离膜10的耐高温性能，而且可以避免基膜100堵孔而降低活性离子传输。在本申请另一些实施方式中，所述无机颗粒的体积平均粒径Dv50为0.8μm-2.3μm。
本申请中，所述无机颗粒的体积平均粒径Dv50是指累计体积分布百分数达到50％时 所对应的粒径，所述隔离膜中无机颗粒的体积平均粒径Dv50的测试方法如下：
(1)将隔离膜的第二涂层300刮粉后在含氧气氛下升温至350℃并保温1h进行烧结，然后加水过滤；
(2)参照标准GB/T 19077-2016，使用激光粒度分析仪(例如Malvern Master Size 3000)对过滤的物质即无机颗粒测试其体积平均粒径Dv50。
在本申请一些实施方式中，所述第二涂层300的厚度为0.5μm-4μm，例如0.6μm-3.9μm，0.7μm-3.6μm，0.8μm-3.5μm，0.9μm-3.2μm，1μm-3μm，1.2μm-2.8μm，1.5μm-2.5μm，1.8μm-2.2μm，1.8μm-2μm等。由此，通过在基膜100的一侧设置该厚度的第二涂层300，可以显著提高隔离膜10的耐高温性能。在本申请另一些实施方式中，所述第二涂层300的厚度为1μm-2μm。
本申请，所述第二涂层300的厚度测试方法包括：首先将待测隔离膜裁成6mm×6mm的待测样品，用两片导电导热的铜箔将待测样品夹住，将待测样品与铜箔之间用双面胶粘住固定，用一定400g平整铁块压1小时，使待测样品与铜箔间缝隙越小越好，然后用剪刀将边缘剪齐，粘在具有导电胶的样品台上，样品略突出样品台边缘即可。然后将样品台装进样品架上锁好固定，打开IB-19500CP氩离子截面抛光仪电源并抽真空至10Pa-4Pa，设置氩气流量为0.15MPa和电压为8KV，以及抛光时间2小时，调整样品台为摇摆模式开始抛光，抛光结束后，使用ZEISS Sigma300扫描电子显微镜得到待测样品的离子抛光断面形貌(CP)图片，即可得出第二涂层300的厚度。
在本申请一些实施方式中，基于所述第二涂层300的总质量，所述无机颗粒的质量占比为30％-70％，例如35％-65％，40％-60％，45％-55％，50％-55％等。由此，通过控制第二涂层300中无机颗粒在上述范围内，可以显著提高隔离膜10的耐高温性能。在本申请另一些实施方式中，基于所述第二涂层300的总质量，所述无机颗粒的质量占比为40％-60％。
本申请中，所述隔离膜10中第二涂层200中无机颗粒的质量占比测试方法包括：对隔离膜10中第二涂层300进行刮粉，将样品进行热失重测试，测试条件：氧气气氛，从25℃升温至350℃，升温速率为5°/min，350℃对应的热失重曲线(热失重(TG)曲线，其纵坐标为重量百分比，横坐标为温度)上对应的纵坐标即为无机颗粒的质量占比。
在本申请一些实施方式中，所述第二涂层300还包括第二粘结剂，作为示例，所述第二粘结剂包括聚四氟乙烯、聚三氟氯乙烯、聚氟乙烯、聚偏二氟乙烯、聚乙烯、聚丙烯、聚丙烯腈、聚环氧乙烷、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物或含氟丙烯酸酯树脂中的至少一种。由此，可以提高第二涂层300与基膜100的粘结性能，避免隔离膜10在使用过程中掉粉，提高电池循环性能。
在本申请第二个方面，本申请提出了一种制备隔离膜的方法，包括：在基膜的一侧形成包括介电材料颗粒的第一涂层，得到隔离膜，所述介电材料颗粒的相对介电常数为1000-10000。
由此，本申请通过在基膜的一侧形成包括上述相对介电常数的介电材料颗粒的第一涂层，可以提高含有其的电池在快充过程的循环性能。
上述介电材料颗粒发挥其性能的过程推测如下：本申请的隔离膜包括上述相对介电常数的介电材料颗粒的第一涂层，含有该隔离膜的电池在充电过程中，介电材料颗粒在电场作用下，材料中的正负电荷中心会发生分离，在内部产生反电场，该介电材料颗粒产生的反电场使得与隔离膜的第一涂层接触的负极极片表面显负电，因此可能会吸引负极极片表面聚集的活性离子均匀分布，从而降低活性离子在负极极片表面聚集而产生金属枝晶的风险，进而提高含有其的电池在快充过程的循环性能。
在本申请的一些实施方式中，可以采用下列步骤：将介电材料颗粒与第一粘结剂和溶剂例如去离子水混合制备得到第一浆料，然后将第一浆料涂布在基膜的一侧，烘干后得到具有第一涂层的隔离膜。
在本申请的再一些实施方式中，可以采用下列步骤：将介电材料颗粒与第一粘结剂和溶剂例如去离子水混合制备得到第一浆料，然后将第一浆料涂布在基膜的一侧，烘干后在基膜的一侧形成包括介电材料颗粒的第一涂层，然后将隔离膜进行翻转，在基膜上远离第一涂层的一侧涂布包括无机颗粒、第二粘结剂和溶剂去离子水的第二浆料，烘干后即可在基膜另一侧形成含有无机颗粒的第二涂层。
在本申请第三方面，本申请提出了一种电池，所述电池包括本申请第一方面所述的隔离膜或采用本申请第二方面所述的方法得到的隔离膜。
电池，是指在放电后可通过充电的方式使活性材料激活而继续使用的电池。
通常情况下，电池包括正极极片、负极极片、隔离膜及电解质。在电池充放电过程中，活性离子在正极极片和负极极片之间往返嵌入和脱出。隔离膜设置在正极极片和负极极片之间(在将正极极片、隔离膜和负极极片进行叠置时，隔离膜上第一涂层与负极极片接触)，起到隔离的作用。电解质在正极极片和负极极片之间起到传导离子的作用。
正极极片包括正极集流体以及设置在正极集流体至少一个表面的正极活性物质层，所述正极活性物质层包括正极活性材料。
作为示例，正极集流体具有在其自身厚度方向相对的两个表面，正极活性物质层设置在正极集流体相对的两个表面的其中任意一者或两者上。
在本申请一些实施方式中，所述正极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可采用铝箔。复合集流体可包括高分子材料基层和形成于高分子材料基层至 少一个表面上的金属层。复合集流体可通过将金属材料(铝、铝合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)，聚对苯二甲酸乙二醇酯(PET)，聚对苯二甲酸丁二醇酯(PBT)，聚苯乙烯(PS)，聚乙烯(PE)等的基材)上而形成。
在本申请一些实施方式中，正极活性材料可采用本领域公知的用于电池的正极活性材料。
作为示例，当所述正极极片用于锂离子电池时，正极活性材料可采用本领域公知的用于锂离子电池的正极活性材料。作为示例，正极活性材料可包括以下材料中的至少一种：橄榄石结构的含锂磷酸盐、锂过渡金属氧化物及其各自的改性化合物。但本申请并不限定于这些材料，还可以使用其他可被用作电池正极活性材料的传统材料。这些正极活性材料可以仅单独使用一种，也可以将两种以上组合使用。其中，锂过渡金属氧化物的示例可包括但不限于锂钴氧化物(如LiCoO2)、锂镍氧化物(如LiNiO2)、锂锰氧化物(如LiMnO2、LiMn2O4)、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物(如LiNi1/3Co1/3Mn1/3O2(也可以简称为NCM333)、LiNi0.5Co0.2Mn0.3O2(也可以简称为NCM523)、LiNi0.5Co0.25Mn0.25O2(也可以简称为NCM211)、LiNi0.6Co0.2Mn0.2O2(也可以简称为NCM622)、LiNi0.8Co0.1Mn0.1O2(也可以简称为NCM811)、锂镍钴铝氧化物(如LiNi0.80Co0.15Al0.05O2)或其改性化合物等中的至少一种。橄榄石结构的含锂磷酸盐的示例可包括但不限于磷酸铁锂(如LiFePO4(也可以简称为LFP))、磷酸铁锂与碳的复合材料、磷酸锰锂(如LiMnPO4)、磷酸锰锂与碳的复合材料、磷酸锰铁锂或磷酸锰铁锂与碳的复合材料中的至少一种。
作为示例，当所述正极极片用于钠离子电池时，正极活性材料可采用本领域公知的用于钠离子电池的正极活性材料。作为示例，所述正极活性材料可以包括但不限于层状过渡金属氧化物、聚阴离子化合物或普鲁士蓝类似物中的至少之一。
作为上述层状过渡金属氧化物的示例，例如可以列举出：
Na1-xCuhFekMnlM1 mO2-y，其中M1包括Li、Be、B、Mg、Al、K、Ca、Ti、Co、Ni、Zn、Ga、Sr、Y、Nb、Mo、In、Sn或Ba中的至少一种，0<x≤0.33，0<h≤0.24，0≤k≤0.32，0<l≤0.68，0≤m<0.1，h+k+l+m＝1，0≤y<0.2；
Na0.67Mn0.7NizM2 0.3-zO2，其中M2包括Li、Mg、Al、Ca、Ti、Fe、Cu、Zn或Ba中的至少一种，0<z≤0.1；
NaaLibNicMndFeeO2，其中0.67<a≤1，0<b<0.2，0<c<0.3，0.67<d+e<0.8，b+c+d+e＝1。
作为上述聚阴离子化合物的示例，例如可以列举出：
A1 fM3 g(PO4)iOjX1 3-j，其中A1包括H、Li、Na、K或NH4中的至少一种，M3包括Ti、Cr、Mn、Fe、Co、Ni、V、Cu或Zn中的至少一种，X1为F、Cl或Br中的至少一种，0<f≤4，0<g≤2，1≤i≤3，0≤j≤2；
NanM4PO4X2，其中M4包括Mn、Fe、Co、Ni、Cu或Zn中的至少一种，X2为F、Cl或Br中的至少一种，0<n≤2；
NapM5 q(SO4)3，其中M5包括Mn、Fe、Co、Ni、Cu或Zn中的至少一种，0<p≤2，0<q≤2；
NasMntFe3-t(PO4)2(P2O7)，其中0<s≤4，0≤t≤3，例如t为0、1、1.5、2或3。
作为上述普鲁士蓝类似物的示例，例如可以列举出：
AuM6 v[M7(CN)6]w·xH2O，其中A包括H+、NH4 +、碱金属阳离子或碱土金属阳离子中的至少一种，M6和M7各自独立地包括过渡金属阳离子中的至少一种，0<u≤2，0<v≤1，0<w≤1，0<x<6。例如A包括H+、Li+、Na+、K+、NH4 +、Rb+、Cs+、Fr+、Be2+、Mg2+、Ca2+、Sr2+、Ba2+或Ra2+中的至少一种，M6和M7各自独立地包括Ti、V、Cr、Mn、Fe、Co、Ni、Cu、Zn、Sn或W中的至少阳离子。
电池在充放电过程中会伴随Li或Na的脱嵌及消耗，电池在放电到不同状态时Li或Na的摩尔含量不同。本申请中关于正极活性材料的列举中，Li或Na的摩尔含量为材料初始状态，即投料前状态，正极活性材料应用于电池体系中，经过充放电循环，Li或Na的摩尔含量会发生变化。
本申请中关于正极活性材料的列举中，氧的摩尔含量仅为理论状态值，晶格释氧会导致氧的摩尔含量发生变化，实际氧的摩尔含量会出现浮动。
在本申请一些实施方式中，正极活性物质层还可选地包括粘结剂。作为示例，所述粘结剂可以包括聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物或含氟丙烯酸酯树脂中的至少一种。
在本申请一些实施方式中，基于所述活性物质层的总质量，所述粘结剂的质量占比为0.5％-3％，例如0.5％，1％，1.5％，2％，2.5％，3％等。
在本申请一些实施方式中，正极活性物质层还可选地包括导电剂。作为示例，所述导电剂可以包括超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯或碳纳米纤维中的至少一种。
在本申请一些实施方式中，基于所述活性物质层的总质量，所述导电剂的质量占比为0.8％-4％，例如0.8％，1％，1.5％，2％，2.5％，3％，3.5％，4％等。
在本申请一些实施方式中，可以通过以下方式制备正极极片：将上述用于制备正极极片的组分，例如正极活性材料、导电剂、粘结剂和任意其他的组分分散于溶剂(例如N-甲基吡咯烷酮)中，形成正极浆料；将正极浆料涂覆在正极集流体上，经烘干、冷压等工序后，即可得到正极极片。
负极极片包括负极集流体以及设置在负极集流体至少一个表面上的负极活性物质层， 所述负极活性物质层包括负极活性材料。
作为示例，负极集流体具有在其自身厚度方向相对的两个表面，负极活性物质层设置在负极集流体相对的两个表面中的任意一者或两者上。
在本申请一些实施方式中，所述负极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可以采用铜箔。复合集流体可包括高分子材料基层和形成于高分子材料基材至少一个表面上的金属层。复合集流体可通过将金属材料(铜、铜合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在本申请一些实施方式中，负极活性材料可采用本领域公知的用于电池的负极活性材料。作为示例，负极活性材料可包括以下材料中的至少一种：人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸盐等。所述硅基材料可包括单质硅、硅氧化合物、硅碳复合物、硅氮复合物或硅合金中的至少一种。所述锡基材料可包括单质锡、锡氧化合物或锡合金中的至少一种。当电池为锂离子电池时，钛酸盐采用钛酸锂；当电池为钠离子电池时，钛酸盐采用钛酸钠。但本申请并不限定于这些材料，还可以使用其他可被用作电池负极活性材料的传统材料。这些负极活性材料可以仅单独使用一种，也可以将两种以上组合使用。
在本申请一些实施方式中，负极活性物质层还可选地包括粘结剂。所述粘结剂可包括丁苯橡胶(SBR)、聚丙烯酸(PAA)、聚丙烯酸钠(PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)、聚甲基丙烯酸(PMAA)或羧甲基壳聚糖(CMCS)中的至少一种。
在本申请一些实施方式中，负极活性物质层还可选地包括导电剂。导电剂可包括超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯或碳纳米纤维中的至少一种。
在本申请一些实施方式中，负极活性物质层还可选地包括其他助剂，例如增稠剂(如羧甲基纤维素钠(CMC-Na))等。
在本申请一些实施方式中，可以通过以下方式制备负极极片：将上述用于制备负极极片的组分，例如负极活性材料、导电剂、粘结剂和任意其他组分分散于溶剂(例如去离子水)中，形成负极浆料；将负极浆料涂覆在负极集流体上，经烘干、冷压等工序后，即可得到负极极片。
通常情况下，电池包括正极极片、负极极片、电解质和隔离膜。在电池充放电过程中，活性离子在正极极片和负极极片之间往返嵌入和脱出。电解质在正极极片和负极极片之间起到传导离子的作用。隔离膜设置在正极极片和负极极片之间，主要起到防止正负极短路 的作用，同时可以使离子通过。
本申请对电解质的种类没有具体的限制，可根据需求进行选择。例如，电解质可以是液态的、凝胶态的或全固态的。
在本申请一些实施方式中，所述电解质采用电解液。所述电解液包括电解质盐和溶剂。
在本申请一些实施方式中，当所述电池为锂离子电池时，电解质盐可包括六氟磷酸锂、四氟硼酸锂、高氯酸锂、六氟砷酸锂、双氟磺酰亚胺锂、双三氟甲磺酰亚胺锂、三氟甲磺酸锂、二氟磷酸锂、二氟草酸硼酸锂、二草酸硼酸锂、二氟二草酸磷酸锂或四氟草酸磷酸锂中的至少一种。
在本申请一些实施方式中，当所述电池为钠离子电池时，所述电解质钠盐可以包括六氟磷酸钠、二氟草酸硼酸钠、四氟硼酸钠、双草酸硼酸钠、高氯酸钠、六氟砷酸钠、双(氟磺酰)亚胺钠、三氟甲基磺酸钠或双(三氟甲基磺酰)亚胺钠中的至少之一。
在本申请一些实施方式中，溶剂可包括碳酸亚乙酯、碳酸亚丙酯、碳酸甲乙酯、碳酸二乙酯、碳酸二甲酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸亚丁酯、氟代碳酸亚乙酯、甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丁酸甲酯、丁酸乙酯、1,4-丁内酯、环丁砜、二甲砜、甲乙砜或二乙砜中的至少一种。
在本申请一些实施方式中，所述电解液还可选地包括添加剂。例如添加剂可以包括负极成膜添加剂、正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温或低温性能的添加剂等。
在一些实施方式中，正极极片、负极极片和隔离膜可通过卷绕工艺或叠片工艺制成电极组件。
在一些实施方式中，二次电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。二次电池的外包装也可以是软包，例如袋式软包。软包的材质可以是塑料，作为塑料，可列举出聚丙烯、聚对苯二甲酸丁二醇酯以及聚丁二酸丁二醇酯等。
本申请对电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。例如，图3是作为一个示例的方形结构的电池单体1。
在一些实施方式中，参照图4，外包装可包括壳体11和盖板13。其中，壳体11可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体11具有与容纳腔连通的开口，盖板13能够盖设于所述开口，以封闭所述容纳腔。正极极片、负极极片和隔离膜可经卷绕工艺或叠片工艺形成电极组件12。电极组件12封装于所述容纳腔内。电解液浸润于电极组件12中。电池单体1所含电极组件12的数量可以为一个或多个，本领域技术人员可根据具体实际需求进行选择。
在一些实施方式中，电池可以组装成电池模块，电池模块所含电池的数量可以为一个 或多个，具体数量本领域技术人员可根据电池模块的应用和容量进行选择。
图5是作为一个示例的电池模块2。参照图5，在电池模块2中，多个电池单体1可以是沿电池模块2的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个电池单体1进行固定。
可选地，电池模块2还可以包括具有容纳空间的外壳，多个电池单体1容纳于该容纳空间。
在一些实施方式中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以为一个或多个，具体数量本领域技术人员可根据电池包的应用和容量进行选择。
图6和图7是作为一个示例的电池包3。参照图6和图7，在电池包3中可以包括电池箱和设置于电池箱中的多个电池模块2。电池箱包括上箱体31和下箱体32，上箱体31能够盖设于下箱体32，并形成用于容纳电池模块2的封闭空间。多个电池模块2可以按照任意的方式排布于电池箱中。
另外，本申请还提供一种用电装置，所述用电装置包括本申请提供的二次电池、电池模块、或电池包中的至少一种。所述二次电池、电池模块、或电池包可以用作所述用电装置的电源，也可以用作所述用电装置的能量存储单元。所述用电装置可以包括移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等，但不限于此。
作为所述用电装置，可以根据其使用需求来选择二次电池、电池模块或电池包。
图8是作为一个示例的用电装置。该用电装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该用电装置对二次电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用电池作为电源。
以下，说明本申请的实施例。下面描述的实施例是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试剂或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。
实施例1
1、正极极片的制备
将正极活性材料镍钴锰酸锂(NCM523即LiNi0.5Co0.2Mn0.3O2)、粘结剂聚偏氟乙烯PVDF、导电剂乙炔黑按照重量比98：1：1进行混合，加入N-甲基吡咯烷酮(NMP)作为 溶剂，在真空状态下搅拌浆料至均匀，得到正极浆料，然后将所得的正极浆料按照14mg/cm2的面密度用刮刀涂布在13μm的铝箔双侧表面上，之后在140℃下烘干，冷压，分切后得到正极极片。
2、负极极片的制备
将负极活性材料人造石墨、导电剂乙炔黑、复合粘结剂SBR(丁苯橡胶)、分散剂羧甲基纤维素钠(CMC-Na)按照重量比为97:1:1:1溶于溶剂去离子水中，搅拌混合均匀后制备成负极浆料，将负极浆料按照15.4mg/cm2的面密度用刮刀涂布在5μm的铜箔双侧表面上。经过烘干、冷压、分切得到负极极片。
3、电解液的制备
在氩气气氛手套箱中(H2O<0.1ppm，O2<0.1ppm)，将有机溶剂碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)按照体积比3:7混合均匀得到有机溶剂，将LiPF6溶解于上述溶剂中，搅拌均匀，得到浓度为1mol/L的电解液。
4、隔离膜
将介电材料颗粒钛酸钡与粘接剂聚偏二氟乙烯和去离子水混合得到第一浆料，将第一浆料涂覆在PE基膜的一侧，然后烘干后去除水分，即可得到隔离膜(隔离膜的一侧具有包括介电材料颗粒的第一涂层，第一涂层厚度为1.5μm)。
5、二次电池的制备
将正极极片、隔离膜、负极极片按顺序叠好(隔离膜上包括介电材料颗粒的第一涂层靠近负极极片)，使隔离膜处于正负极中间起到隔离的作用，并卷绕得到裸电芯。将裸电芯置于外包装中，注入上述电解液并封装，得到锂离子电池。
实施例2-13以及对比例1-2的锂离子电池的制备方法同于实施例1，区别在于制备隔离膜的过程不同，具体如表1所示。
表1
实施例14-21以及对比例3的锂离子电池的制备方法同于实施例1，区别在于制备隔离膜的过程不同，具体包括：将介电材料颗粒钛酸钡与粘接剂聚偏二氟乙烯和去离子水混合得到第一浆料，将勃姆石与粘接剂聚偏二氟乙烯和去离子水混合得到第二浆料，然后将第二浆料涂覆在PE基膜的一侧，烘干后(在隔离膜的一侧形成包括介电材料的第一涂层，第一涂层厚度为1.5μm)，将第二浆料涂覆在PE基膜的另一侧，然后烘干后(在隔离膜的另一侧形成包括无机颗粒的第二涂层，第二涂层厚度为1.5μm)，裁切，即可得到隔离膜，具体如表2所示。
表2

对实施例1-13和对比例1-3电池的析锂情况以及循环性能进行表征，表征结果如表3所示，对实施例14-21的电池的析锂情况以及循环性能以及隔离膜的耐高温性能进行表征，表征结果如表5所示。
(1)负极极片析锂情况测试：
将电池在4C条件下充电到4.4V，静置5min，然后在1C条件下放电到2.8V，静置5min，按照上述充放电流程循环500圈，然后拆解负极极片，，采用背向散射电子衍射技术(EBSD)在真空条件下对拆解负极极片表面进行扫描(其中采用的扫描式电子显微镜(Scanning Electron Microscopy,SEM)的扫描角度为70度)，分别收集析锂面积信号和未析锂面积信号，析锂面积占比＝析锂面积信号的强度/(析锂面积信号的强度+未析锂面积的信号强度)。
(2)循环性能测试：
在25℃下，将电池以2C倍率充电恒流充电至截止电压4V，然后以1C倍率放电至截止电压2.8V，记录初始容量为C0，然后按照表4所示策略充电，以1C倍率放电，记录每次循环的放电容量Cn，直至电池的容量保持率(容量保持率＝Cn/C0×100％)为80％，记录循环圈数。循环圈数越多，则代表二次电池的循环性能越好。
(3)隔离膜耐高温性能测试：
在25℃下，将电池以0.33C倍率恒流充电至截止电压4V(100％SOC)，然后以5℃/min的升温速率升温到100℃，搁置1h，之后以5℃/min的升温速率加温到105℃，搁置30min，持续以5℃/min的升温速率升高5℃，每升高5℃后保持30min，直至电芯失效(电芯爆炸或起火视为电芯失效)，记录电芯失效时刻的温度。
表4

表3
结论，实施例1-13与对比例1-2相比，实施例1-13电池的隔离膜的第一涂层均含有相对介电常数为1000-10000的介电材料颗粒；对比例1电池的隔离膜中未加入介电材料颗粒，对比例2电池的隔离膜中第一涂层的介电材料颗粒采用相对介电常数为70的氧化铝颗粒。由表3数据可知，实施例1-13电池循环拆解后的负极极片的析锂面积明显小于对比例1-2，并且实施例1-13电池的循环性能也高于对比例1-2。由此表明，本申请的隔离膜中第一涂层采用相对介电常数为1000-10000的介电材料颗粒，不仅可以减少快充过程的析锂风险，而且可以提高电池快充过程循环性能。
表5
结论，实施例14-21与对比例3相比，实施例14-21电池的隔离膜的第一涂层均含有相对介电常数为1000-10000的介电材料颗粒，第二涂层中含有无机颗粒；对比例3电池的第一涂层介电材料颗粒采用相对介电常数为70的氧化铝颗粒，并且第二涂层中含有无机颗粒。由表5数据可知，实施例14-21电池循环拆解后的负极极片的析锂面积明显小于对比例3，并且实施例14-21电池的循环性能也高于对比例3。同时实施例14-21电池的隔离膜具有较高的耐高温性能。由此表明，本申请的隔离膜中第一涂层采用相对介电常数为1000-10000的介电材料颗粒以及第二涂层采用无机颗粒，不仅可以减少快充过程的析锂风险，而且可以提高电池快充过程循环性能，并且还可以提高隔离膜的耐高温性能。
需要说明的是，本申请不限定于上述实施方式。上述实施方式仅为示例，在本申请的技术方案范围内具有与技术思想实质相同的构成、发挥相同作用效果的实施方式均包含在本申请的技术范围内。此外，在不脱离本申请主旨的范围内，对实施方式施加本领域技术人员能够想到的各种变形、将实施方式中的一部分构成要素加以组合而构筑的其它方式也包含在本申请的范围内。

Claims (20)

  1. 一种隔离膜，其中，包括：
    基膜；
    第一涂层，所述第一涂层设在所述基膜的一侧，所述第一涂层包括介电材料颗粒，所述介电材料颗粒的相对介电常数为1000-10000。
  2. 根据权利要求1所述的隔离膜，其中，所述介电材料颗粒的相对介电常数为1500-5000。
  3. 根据权利要求1或2所述的隔离膜，其中，所述介电材料颗粒的体积平均粒径Dv50为200nm-2000nm。
  4. 根据权利要求1-3中任一项所述的隔离膜，其中，所述介电材料颗粒的体积平均粒径Dv50为500nm-1500nm。
  5. 根据权利要求1-4中任一项所述的隔离膜，其中，所述介电材料颗粒包括钛酸钡、钛酸铅、铌酸锂、锆钛酸铅、偏铌酸铅或铌酸铅钡锂中的至少一种。
  6. 根据权利要求1-5中任一项所述的隔离膜，其中，基于所述第一涂层的总质量，所述介电材料颗粒的质量占比为20％-80％。
  7. 根据权利要求1-6中任一项所述的隔离膜，其中，基于所述第一涂层的总质量，所述介电材料颗粒的质量占比为30％-70％。
  8. 根据权利要求1-7中任一项所述的隔离膜，其中，所述第一涂层的厚度为0.5μm-2μm。
  9. 根据权利要求1-8中任一项所述的隔离膜，其中，所述介电材料颗粒的BET比表面积为0.5m2/g-6m2/g。
  10. 根据权利要求1-9中任一项所述的隔离膜，其中，所述第一涂层还包括第一粘结剂。
  11. 根据权利要求10所述的隔离膜，其中，所述第一粘结剂包括聚四氟乙烯、聚三氟氯乙烯、聚氟乙烯、聚偏二氟乙烯、聚乙烯、聚丙烯、聚丙烯腈、聚环氧乙烷、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物或含氟丙烯酸酯树脂中的至少一种。
  12. 根据权利要求1-11中任一项所述的隔离膜，其中，还包括第二涂层，所述第二涂层设在所述基膜上远离所述第一涂层的一侧，所述第二涂层包括无机颗粒。
  13. 根据权利要求12所述的隔离膜，其中，所述无机颗粒包括二氧化硅、氧化铝、二氧化锆、氧化锌、氧化镁、硫酸钠、硫酸钡、勃姆石或碳酸钙中的至少之一。
  14. 根据权利要求12或13所述的隔离膜，其中，所述无机颗粒的体积平均粒径Dv50 为0.5μm-2.5μm。
  15. 根据权利要求12-14中任一项所述的隔离膜，其中，所述第二涂层的厚度为0.5μm-4μm。
  16. 根据权利要求12-15中任一项所述的隔离膜，其中，基于所述第二涂层的总质量，所述无机颗粒的质量占比为30％-70％。
  17. 根据权利要求12-16中任一项所述的隔离膜，其中，所述第二涂层包括第二粘结剂。
  18. 一种制备隔离膜的方法，其中，包括：在基膜的一侧形成包括介电材料颗粒的第一涂层，得到隔离膜，所述介电材料颗粒的相对介电常数为1000-10000。
  19. 一种电池，其中，包括权利要求1-17中任一项所述的隔离膜或采用权利要求18所述的方法得到的隔离膜。
  20. 一种用电装置，其中，包括权利要求19所述的电池。
PCT/CN2024/119787 2024-01-03 2024-09-19 隔离膜及其制备方法、电池和用电装置 Pending WO2025145671A1 (zh)

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