WO2022110227A1 - 一种隔离膜、其制备方法及其相关的二次电池、电池模块、电池包和装置 - Google Patents

一种隔离膜、其制备方法及其相关的二次电池、电池模块、电池包和装置 Download PDF

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Publication number
WO2022110227A1
WO2022110227A1 PCT/CN2020/132955 CN2020132955W WO2022110227A1 WO 2022110227 A1 WO2022110227 A1 WO 2022110227A1 CN 2020132955 W CN2020132955 W CN 2020132955W WO 2022110227 A1 WO2022110227 A1 WO 2022110227A1
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Prior art keywords
organic particles
coating
particles
separator
copolymer
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PCT/CN2020/132955
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English (en)
French (fr)
Inventor
洪海艺
程丛
兰媛媛
杨建瑞
柳娜
金海族
Original Assignee
宁德时代新能源科技股份有限公司
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Application filed by 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to PCT/CN2020/132955 priority Critical patent/WO2022110227A1/zh
Priority to EP20963115.9A priority patent/EP4109658A4/en
Priority to KR1020227029850A priority patent/KR102537203B1/ko
Priority to JP2022552619A priority patent/JP7446459B2/ja
Priority to CN202080095489.9A priority patent/CN115104219B/zh
Publication of WO2022110227A1 publication Critical patent/WO2022110227A1/zh
Priority to US17/950,978 priority patent/US20230024649A1/en

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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
    • H01M50/451—Separators, membranes or diaphragms characterised by the material having a layered structure comprising layers of only organic material and layers containing 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
    • 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
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • H01M50/207—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape
    • H01M50/209—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape adapted for prismatic or rectangular cells
    • 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
    • H01M50/411—Organic 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
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • 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
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/417—Polyolefins
    • 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
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/42—Acrylic resins
    • 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
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/426—Fluorocarbon polymers
    • 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
    • H01M50/431—Inorganic material
    • H01M50/434—Ceramics
    • 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
    • H01M50/443—Particulate 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
    • H01M50/449—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
    • 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
    • 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
    • H01M50/494—Tensile strength
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application belongs to the technical field of secondary batteries, and specifically relates to a separator, a secondary battery containing the same, and related battery modules, battery packs and devices.
  • Secondary batteries are widely used in various consumer electronic products and electric vehicles due to their outstanding features such as light weight, no pollution, and no memory effect.
  • a first aspect of the present application provides a separator, which aims to enable a secondary battery containing the separator to have good cycle performance and safety performance at the same time.
  • the release film of the first aspect of the present application comprises: a substrate and a coating layer formed on at least one surface of the substrate.
  • the coating includes inorganic particles and organic particles.
  • the organic particles include a first organic particle and a second organic particle.
  • the first organic particles and the second organic particles are embedded in the inorganic particles and form protrusions on the surface of the coating.
  • the number-average particle size of the first organic particles is greater than 10 ⁇ m, and the number-average particle size of the second organic particles is 2 ⁇ m-10 ⁇ m.
  • the present application at least includes the following beneficial effects:
  • the separator of the present application contains inorganic particles and organic particles in the same coating, and compared with the separator with two coatings of inorganic particle layer and organic particle layer, the thickness of the separator is greatly reduced, thereby improving the energy of the battery and the organic particles include the first type of organic particles and the second type of organic particles with a specific particle size, compared with the case where only one type of organic particles is included, so that the secondary battery can be Sufficient and unevenly distributed voids are formed between the inorganic particles to ensure smooth ion transport channels, so that the battery has good cycle performance; at the same time, when the secondary battery is operating at high temperature, the first and second organic particles can form
  • the large-area film structure can reduce or block the transmission channel of the spacer, delay the thermal spread of the battery, and make the battery obtain good safety performance.
  • the number-average particle size of the first organic particles may be 12 ⁇ m-25 ⁇ m; optionally, the number-average particle size of the first organic particles is 15 ⁇ m-20 ⁇ m.
  • the cycle performance of the battery can be further improved.
  • the number-average particle size of the second organic particles may be 2 ⁇ m-8 ⁇ m; optionally, the number-average particle size of the second organic particles is 3 ⁇ m-7 ⁇ m.
  • the cycle performance and safety performance of the battery can be further improved.
  • the ratio of the number-average particle size of the first organic particles to the number-average particle size of the second organic particles is ⁇ 1.5;
  • the ratio of the number-average particle size to the number-average particle size of the second organic particles is ⁇ 2.0.
  • the first organic particles are secondary particles.
  • the safety performance of the battery can be further improved.
  • the second organic particles are primary particles.
  • the cycle performance and safety performance of the battery can be further improved.
  • the weight of the single-sided coating on the separator per unit area is less than or equal to 3.0 g/m 2 ; optionally, the weight of the single-sided coating on the separator per unit area is 1.5 g/m 2 - 2.5g/m 2 .
  • the energy density of the battery can be further improved on the premise of ensuring the battery cycle performance and safety performance.
  • the volume average particle diameter Dv50 of the inorganic particles is ⁇ 2.5 ⁇ m; optionally, the volume average particle diameter Dv50 of the inorganic particles is 0.5 ⁇ m-2.5 ⁇ m.
  • the separator can further improve the volume energy density of the battery under the premise of better cycle performance and safety performance.
  • the mass percentage of the inorganic particles in the coating is ⁇ 70%, optionally, the mass percentage of the inorganic particles in the coating is 60%-70%.
  • the mass proportion of inorganic particles is controlled within the given range, the mass energy density of the battery can be further improved on the premise of ensuring the safety performance of the separator.
  • the mass percentage of the first organic particles in the coating is ⁇ 12%, optionally, the mass percentage of the first organic particles in the coating is 15% %-25%.
  • the mass proportion of the first organic particles is controlled within the given range, the cycle performance and safety performance of the battery can be improved.
  • the mass percentage of the second organic particles in the coating is ⁇ 10%, optionally, the mass percentage of the second organic particles in the coating is 2 %-10%.
  • the mass ratio of the second organic particles is controlled within the given range, the cycle performance and safety performance of the battery can be improved.
  • the three can play a better synergistic effect, ensure the safety performance of the separator and improve the energy density of the battery.
  • the first organic particles may include homopolymers or copolymers of fluorine-containing alkenyl monomer units, homopolymers or copolymers of olefin-based monomer units, unsaturated nitrile monomers Homopolymers or copolymers of monomer units, homopolymers or copolymers of alkylene oxide monomer units, and one or more of the modified compounds of the above-mentioned homopolymers or copolymers.
  • the first organic particles may include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polycyclic Ethylene oxide, copolymers of fluoroalkenyl monomer units and vinyl monomer units, copolymers of fluoroalkenyl monomer units and acrylic monomer units, fluoroalkenyl monomer units and acrylate monomers A copolymer of monomer units, and one or more of the modified compounds of the above-mentioned homopolymers or copolymers.
  • the first organic particles may include vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-trifluoroethylene-hexafluoroethylene Propylene copolymer, vinylidene fluoride-hexafluoropropylene-acrylic acid copolymer, vinylidene fluoride-hexafluoropropylene-acrylate copolymer, and one or more modified compounds of the above-mentioned copolymers.
  • the second organic particles may include homopolymers or copolymers of acrylic monomer units, homopolymers or copolymers of acrylic monomer units, and styrene monomer units.
  • homopolymers or copolymers of acrylic monomer units homopolymers or copolymers of acrylic monomer units
  • styrene monomer units One or more of the above-mentioned homopolymers or copolymers, polyurethane compounds, rubber compounds, and modified compounds of the above-mentioned homopolymers or copolymers.
  • the second organic particles may include copolymers of acrylic monomer units and styrene monomer units, copolymers of acrylic monomer units and styrene monomer units, and acrylic monomers.
  • the second organic particles may include butyl acrylate-styrene copolymer, butyl methacrylate-isooctyl methacrylate copolymer, isooctyl methacrylate-styrene Copolymer, Methacrylate-Methacrylic Acid-Styrene Copolymer, Methyl Acrylate-Isooctyl Methacrylate-Styrene Copolymer, Butyl Acrylate-Isooctyl Acrylate-Styrene Copolymer, Butyl Acrylate - Isooctyl Methacrylate-Styrene Copolymer, Butyl Methacrylate-Isooctyl Acrylate-Styrene Copolymer, Butyl Methacrylate-Isooctyl Methacrylate-Styrene Copolymer, Styrene-
  • the inorganic particles may include boehmite ( ⁇ -AlOOH), alumina (Al 2 O 3 ), barium sulfate (BaSO 4 ), magnesium oxide (MgO), magnesium hydroxide (Mg(OH) ) 2 ), silicon dioxide (SiO 2 ), tin dioxide (SnO 2 ), titanium oxide (TiO 2 ), calcium oxide (CaO), zinc oxide (ZnO), zirconium oxide (ZrO 2 ), yttrium oxide (Y 2 O 3 ), nickel oxide (NiO), cerium oxide (CeO 2 ), zirconium titanate (SrTiO 3 ), barium titanate (BaTiO 3 ), and magnesium fluoride (MgF 2 ).
  • boehmite ⁇ -AlOOH
  • alumina Al 2 O 3
  • barium sulfate BaSO 4
  • magnesium oxide MgO
  • magnesium hydroxide Mg(OH) 2
  • silicon dioxide SiO 2
  • the air permeability of the isolation film may be 100s/100mL-300s/100mL; optionally, the air permeability of the isolation film may be 150s/100mL-250s/100mL.
  • the transverse tensile strength (MD) of the separator may be 1500kgf/cm 2 -3000kgf/cm 2 ; optionally, the transverse tensile strength of the separator may be 1800kgf/cm 2 -2500kgf/cm 2 .
  • the longitudinal tensile strength (TD) of the separator may be 1000kgf/cm 2 -2500kgf/cm 2 ; optionally, the longitudinal tensile strength of the separator may be 1400kgf/cm 2 -2000kgf/cm 2 .
  • the transverse elongation at break of the separator may be 50%-200%; optionally, the transverse elongation at break of the separator may be 100%-150%.
  • the longitudinal elongation at break of the separator may be 50%-200%; optionally, the longitudinal elongation at break of the separator may be 100%-150%.
  • the inorganic particles and the organic particles form a non-uniform pore structure in the coating.
  • the distance between any two adjacent inorganic particles is denoted as L1
  • the distance between any adjacent one inorganic particle and one organic particle is denoted as L2, then L1 ⁇ L2.
  • a second aspect of the present application provides a method for preparing an isolation film, comprising the steps of:
  • (1) Provide the base material.
  • (2) providing a coating slurry including a component material and a solvent, the component material including inorganic particles and organic particles, the organic particles including a first organic particle and a second organic particle .
  • (3) Coating the coating slurry described in step (2) on at least one side of the substrate described in step (1) to form a coating layer and drying to obtain the separator.
  • the dried coating includes the inorganic particles, the first organic particles and the second organic particles.
  • the first organic particles and the second organic particles are embedded in the inorganic particles and form protrusions on the surface of the dried coating.
  • the number-average particle size of the first organic particles is greater than 10 ⁇ m, and the number-average particle size of the second organic particles is 2 ⁇ m-10 ⁇ m.
  • step (2) the added mass of the first organic particles accounts for more than 12% of the total dry weight of the component materials; optionally, it is 12%-30%.
  • step (2) the added mass of the second type of organic particles accounts for less than 10% of the total dry weight of the component materials, optionally 2%-10%.
  • step (2) the solid content of the coating slurry is 28%-45%, optionally 30%-38%, based on weight.
  • a coating machine is used for the coating, and the coating machine includes a gravure roll, and the number of lines of the gravure roll is 100LPI-300LPI, optionally 125LPI- 190LPI.
  • the coating speed is 30m/min-90m/min, optionally 50m/min-70m/min.
  • step (3) the line speed ratio of the coating is 0.8-2.5, optionally 0.8-1.5.
  • the drying temperature is 40°C-70°C, optionally 50°C-60°C.
  • the drying time is 10s-120s, optionally 20s-80s.
  • a third aspect of the present application provides a secondary battery comprising the separator according to the first aspect of the present application or a separator prepared by the method according to the second aspect of the present application.
  • a fourth aspect of the present application provides a battery module including the secondary battery according to the third aspect of the present application.
  • a fifth aspect of the present application provides a battery pack including the battery module according to the fourth aspect of the present application.
  • a sixth aspect of the application provides an apparatus comprising at least one of the secondary battery according to the third aspect of the application, the battery module according to the fourth aspect of the application, or the battery pack according to the fifth aspect of the application.
  • FIG. 1 is a schematic structural diagram of an embodiment of the isolation film of the present application.
  • FIG. 2 is an ion-polished cross-sectional topography (CP) picture of an embodiment of the isolation film of the present application at a magnification of 3000 times.
  • CP cross-sectional topography
  • FIG. 3 is a scanning electron microscope (SEM) picture at a magnification of 3000 times of an embodiment of the separator of the present application.
  • FIG. 4-1 is a schematic structural diagram of an embodiment of the isolation film of the present application.
  • 4-2 is a schematic structural diagram of another embodiment of the isolation film of the present application.
  • FIG. 5 is a schematic diagram of an embodiment of a secondary battery.
  • FIG. 6 is an exploded view of FIG. 5 .
  • FIG. 7 is a schematic diagram of one embodiment of a battery module.
  • FIG. 8 is a schematic diagram of an embodiment of a battery pack.
  • FIG. 9 is an exploded view of FIG. 8 .
  • FIG. 10 is a schematic diagram of one embodiment of a device in which a secondary battery is used as a power source.
  • any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with any other lower limit to form an unspecified range, and likewise any upper limit can be combined with any other upper limit to form an unspecified range.
  • each individually disclosed point or single value may itself serve as a lower or upper limit in combination with any other point or single value or with other lower or upper limits to form a range that is not expressly recited.
  • the term "or” is inclusive. That is, the phrase “A or (or) B” means “A, B, or both A and B.” More specifically, the condition "A or B” is satisfied by either of the following: A is true (or present) and B is false (or absent); A is false (or absent) and B is true (or present) ; or both A and B are true (or present).
  • a secondary battery refers to a battery that can continue to be used by activating the active material by charging after the battery is discharged.
  • a secondary battery typically includes a positive electrode, a negative electrode, a separator, and an electrolyte.
  • active ions are inserted and extracted back and forth between the positive electrode and the negative electrode.
  • the separator is arranged between the positive pole piece and the negative pole piece, and plays the role of isolation.
  • the electrolyte plays the role of conducting ions between the positive electrode and the negative electrode.
  • the release film provided by the present application includes: a substrate and a coating formed on at least one surface of the substrate.
  • the coating includes inorganic particles and organic particles.
  • the organic particles include a first organic particle and a second organic particle, and the first organic particle and the second organic particle are embedded in the inorganic particle and form protrusions on the surface of the coating.
  • the number-average particle size of the first organic particles is greater than 10 ⁇ m, and the number-average particle size of the second organic particles is 2 ⁇ m-10 ⁇ m.
  • the number-average particle size of the organic particles refers to the arithmetic mean value of the particle size of the organic particles in the separator coating based on the number of organic particles.
  • the particle size of the organic particles refers to the distance between two points on the organic particles that are farthest apart.
  • the separator of the present application contains inorganic particles and organic particles in the same coating, which greatly reduces the overall size of the separator compared to separators having two coatings of an inorganic particle layer and an organic particle layer Thickness, thereby improving the energy density of the battery; and the organic particles include the first organic particle and the second organic particle with a specific number average particle size and structural design. Under the mutual cooperation of the two, the battery can be well balanced cycle performance and safety performance.
  • the first type of organic particles and the second type of organic particles with a specific particle size range are used in combination. When the battery is in a normal working environment (for example, below 45°C), the combination of the two can effectively reduce the coating.
  • the separator of the present application can further improve the performance of the secondary battery if it also optionally satisfies one or more of the following conditions.
  • the number average particle size of the first organic particles is 12 ⁇ m-25 ⁇ m; for example, the number average particle size of the first organic particles may be 15 ⁇ m-25 ⁇ m, 12 ⁇ m-23 ⁇ m, 13 ⁇ m-22 ⁇ m , 15 ⁇ m-20 ⁇ m, 12 ⁇ m-18 ⁇ m, etc.
  • the number-average particle size of the first organic particles is within the given range, sufficient voids can exist between the organic particles, and even if the organic particles swell in the electrolyte, sufficient ion transport channels can be formed, thereby further improving the Cycling performance of the battery.
  • the number average particle size of the second organic particles may be 2 ⁇ m-9 ⁇ m; for example, the number average particle size of the second organic particles may be 2 ⁇ m-8 ⁇ m, 2.5 ⁇ m-7 ⁇ m, 2.5 ⁇ m- 5 ⁇ m, 3 ⁇ m-7 ⁇ m, 2 ⁇ m-6 ⁇ m, 3 ⁇ m-5.5 ⁇ m, etc.
  • the inventors have found that when the number average particle size of the second organic particles is within the given range, the cycle performance and safety performance of the battery can be further improved.
  • the number-average particle size of the second type of organic particles is too small (for example, less than 2 ⁇ m), it is easy to swell in the electrolyte to form a film structure, and when the battery is working normally, it will block the spacer transmission channel, thereby affecting the cycle performance of the battery; If the number average particle size of the second type of organic particles is too large (for example, greater than 10 ⁇ m), it may cause excessively firm adhesion between the separator and the electrode sheet after the hot pressing process of battery preparation, resulting in poor infiltration of the electrolyte. , thereby affecting the cycle performance of the battery.
  • the ratio of the number average particle size of the first organic particles to the number average particle size of the second organic particles is ⁇ 1.5; for example, the number average particle size of the first organic particles
  • the ratio to the number average particle size of the second organic particles may be 1.5-5, 2-4, 2.5-3.5, 2.5-5.5, 3-4.5, 3-4, etc.
  • the cycle performance and safety performance of the battery can be further improved by selecting the appropriate number-average particle size ratio of the two.
  • the first organic particles are secondary particles.
  • the separator coating includes the first organic particles with secondary particle morphology, it helps to form a uniform coating interface, and when the separator is applied to the battery, it can effectively improve the tab dislocation during the battery preparation process. problem, so as to further improve the safety performance of the battery.
  • the second organic particles are primary particles.
  • the first organic particles serve to create the gap; the second organic particles serve to enhance the adhesion between the separator and the electrode sheet (eg, positive electrode or negative electrode) effect.
  • Primary particles refer to particles that do not form an agglomerated state.
  • Secondary particles refer to the agglomerated particles formed by the aggregation of two or more primary particles.
  • the separator includes a substrate (A) and a coating layer (B), and the coating layer (B) includes first organic particles (B1), second organic particles (B2) and Inorganic particles (B3), the first organic particles (B1) are secondary particles, the second organic particles (B2) are primary particles, and both the first organic particles and the second organic particles are embedded in the inorganic particles ( B3) and forming protrusions on the surface of the coating layer (B).
  • first organic particles (B1) are secondary particles
  • the second organic particles (B2) are primary particles
  • both the first organic particles and the second organic particles are embedded in the inorganic particles ( B3) and forming protrusions on the surface of the coating layer (B).
  • the first organic particles may include homopolymers or copolymers of fluorine-containing olefinic monomer units, homopolymers or copolymers of olefinic monomeric units, unsaturated nitrile monomeric units The homopolymer or copolymer, the homopolymer or copolymer of alkylene oxide monomer units, and one or more of the modified compounds of each of the above homopolymers or copolymers.
  • the fluorine-containing alkenyl monomer unit may be selected from one or more of vinylidene fluoride, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, and hexafluoropropylene .
  • the olefin-based monomer unit may be selected from one or more of ethylene, propylene, butadiene, isoprene, and the like.
  • the unsaturated nitrile monomer units may be selected from one or more of acrylonitrile, methacrylonitrile, and the like.
  • the alkylene oxide monomer units may be selected from one or more of ethylene oxide, propylene oxide, and the like.
  • the first organic particles may include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide Alkane, copolymers of different fluoroalkenyl monomer units, copolymers of fluoroalkenyl monomer units and olefinic monomer units, copolymers of fluoroalkenyl monomer units and acrylic monomer units, fluorine-containing A copolymer of an ethylenic monomer unit and an acrylate monomer unit, and one or more of the modified compounds of the above-mentioned homopolymers or copolymers.
  • the first organic particles may include vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-trifluoroethylene-hexafluoropropylene copolymer compound, vinylidene fluoride-hexafluoropropylene-acrylic acid copolymer, vinylidene fluoride-hexafluoropropylene-acrylate copolymer, and one or more modified compounds of the above-mentioned copolymers.
  • the second organic particles may include homopolymers or copolymers of acrylic monomer units, homopolymers or copolymers of acrylic monomer units, homopolymers or copolymers of styrene monomer units polymer or copolymer, polyurethane-based compound, rubber-based compound, and one or more of the modified compounds of the above-mentioned homopolymers or copolymers.
  • the second organic particles may include copolymers of acrylic monomer units and styrene monomer units, copolymers of acrylic monomer units and styrene monomer units, acrylic monomers Monomer unit - acrylate monomer unit - copolymer of styrene monomer unit, copolymer of styrene monomer unit and unsaturated nitrile monomer unit, styrene monomer unit - olefin monomer Units - copolymers of unsaturated nitrile monomer units, and one or more of the modified compounds of the above materials.
  • the acrylate-based monomer units may be selected from methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, butyl methacrylate, isooctyl methacrylate One or more of esters, etc.
  • the acrylic monomer unit may be selected from one or more of acrylic acid, methacrylic acid, and the like.
  • the styrene-based monomer units may be selected from one or more of styrene, methylstyrene, and the like.
  • the unsaturated nitrile monomer units may be selected from one or more of acrylonitrile, methacrylonitrile, and the like.
  • the second organic particles may include butyl acrylate-styrene copolymer, butyl methacrylate-iso-octyl methacrylate copolymer, isooctyl methacrylate-styrene copolymer , methacrylate - methacrylic acid - styrene copolymer, methyl acrylate - isooctyl methacrylate - styrene copolymer, butyl acrylate - isooctyl acrylate - styrene copolymer, butyl acrylate - methyl acrylate Isooctyl acrylate-styrene copolymer, butyl methacrylate-isooctyl acrylate-styrene copolymer, butyl methacrylate-isooctyl methacrylate-styrene copolymer
  • the modified compound of each homopolymer or copolymer refers to a modified compound obtained by copolymerizing a monomer unit in each homopolymer or copolymer with a monomer unit containing a specific functional group.
  • a modified compound or the like can be obtained by copolymerizing a fluorine-containing alkenyl monomer unit with a carboxyl-functional group-containing compound.
  • the number average molecular weight of the first organic particles is 300,000-800,000, such as 400,000-650,000, and the like.
  • the number average molecular weight of the second organic particles is 10,000-100,000, such as 20,000-80,000.
  • the inorganic particles may include boehmite ( ⁇ -AlOOH), alumina (Al 2 O 3 ), barium sulfate (BaSO 4 ), magnesium oxide (MgO), magnesium hydroxide (Mg(OH) 2 ), silicon dioxide (SiO 2 ), tin dioxide (SnO 2 ), titanium oxide (TiO 2 ), calcium oxide (CaO), zinc oxide (ZnO), zirconium oxide (ZrO 2 ), yttrium oxide (Y 2 )
  • One or more of O 3 nickel oxide (NiO), cerium oxide (CeO 2 ), zirconium titanate (SrTiO 3 ), barium titanate (BaTiO 3 ), magnesium fluoride (MgF 2 ); for example,
  • the inorganic particles may include one or more of boehmite ( ⁇ -AlOOH) and alumina (Al 2 O 3 ).
  • the volume average particle diameter Dv50 of the inorganic particles is ⁇ 2.5 ⁇ m; for example, the particle diameters of the inorganic particles may be 0.5 ⁇ m-2.5 ⁇ m, 1.5 ⁇ m-2.5 ⁇ m, 0.3 ⁇ m-0.7 ⁇ m, etc.
  • the separator can further improve the volume energy density of the battery under the premise of better cycle performance and safety performance.
  • the mass proportion of the inorganic particles in the coating is ⁇ 70% (based on the total mass of the coating); for example, the mass proportion of the inorganic particles in the coating It can be 60%-70%, 65%-70%, etc.
  • the mass proportion of inorganic particles is controlled within the given range, the mass energy density of the battery can be further improved on the premise of ensuring the safety performance of the separator.
  • the mass proportion of the first organic particles in the coating is ⁇ 12% (based on the total mass of the coating); for example, the first organic particles are in the coating
  • the mass ratio in the layer can be 12%-30%, 15%-30%, 15%-25%, 15%-20%, etc.
  • the separator and the pole piece can have enough space for stress release during the battery cycle, further improving the interface of the electrode and pole piece.
  • a suitable quality The proportion range can also reduce the consumption of the electrolyte by the separator, thereby further improving the cycle performance and safety performance of the battery.
  • the mass ratio of the second organic particles in the coating is ⁇ 10% (based on the total mass of the coating); for example, the second organic particles are in the coating
  • the mass ratio in the layer can be 2%-10%, 3%-8%, 4%-9%, 5%-10%, etc.
  • the three can play a better synergistic effect, ensuring that the separator has an appropriate pore structure on the premise of ensuring safety performance, and at the same time The weight reduction of the separator is achieved, thereby further improving the energy density of the battery.
  • the single-sided coating weight per unit area of the isolation film is ⁇ 3.0 g/m 2 ; for example, the single-sided coating weight per unit area of the isolation film may be 1.5 g/m 2 -3.0 g/ m 2 , 1.5g/m 2 -2.5g/m 2 , 1.8g/m 2 -2.3g/m 2 , etc. Controlling the coating weight on one side of the separator per unit area within the given range can further improve the energy density of the battery on the premise of ensuring the battery cycle performance and safety performance.
  • other organic compounds may also be included in the coating, for example, polymers that improve heat resistance, dispersants, wetting agents, other kinds of binders, and the like may be included.
  • the other organic compounds mentioned above are all non-particulate substances in the coating. There is no particular limitation on the types of the above-mentioned other organic compounds in the present application, and any known materials with good improved properties can be selected.
  • the substrate can be a single-layer film or a multi-layer composite film.
  • the materials of each layer can be the same or different.
  • the thickness of the substrate is ⁇ 10 ⁇ m; for example, the thickness of the substrate may be 5 ⁇ m-10 ⁇ m, 5 ⁇ m-9 ⁇ m, 7 ⁇ m-10 ⁇ m, and the like.
  • the thickness of the substrate is controlled within a given range, the battery energy density can be further improved on the premise of ensuring the battery cycle performance and safety performance.
  • the air permeability of the separator can be 100s/100mL-300s/100mL; for example, the air permeability of the separator can be 150s/100mL-250s/100mL, 170s/100mL-220s/100mL, etc. .
  • the transverse tensile strength (MD) of the release film may be 1500kgf/cm 2 -3000kgf/cm 2 ; for example, the transverse tensile strength of the release film may be 1800kgf/cm 2 -2500kgf/ cm 2 etc.
  • the longitudinal tensile strength (TD) of the separator may be 1000kgf/cm 2 -2500kgf/cm 2 ; for example, it may be 1400kgf/cm 2 -2000kgf/cm 2 and the like.
  • the lateral elongation at break of the separator may be 50%-200%; for example, the lateral elongation at break of the separator may be 100%-150%.
  • the longitudinal elongation at break of the separator may be 50%-200%; for example, the longitudinal elongation at break of the separator may be 100%-150%.
  • the distance between any two adjacent inorganic particles is recorded as L1
  • the distance between any adjacent one inorganic particle and one organic particle is recorded as L2, then L1 ⁇ L2.
  • the particle size and number average particle size of the organic particles can be tested using equipment and methods known in the art. For example, using a scanning electron microscope (eg ZEISS Sigma 300), referring to JY/T010-1996, a scanning electron microscope (SEM) picture of the separator is obtained.
  • a scanning electron microscope eg ZEISS Sigma 300
  • multiple test samples (for example, 10) can be taken to repeat the above test, and the average value of each test sample is taken as the final test result.
  • the morphology of the organic particles can be tested using equipment and methods known in the art.
  • testing can be performed by using a scanning electron microscope (eg ZEISS Sigma 300).
  • a scanning electron microscope eg ZEISS Sigma 300.
  • the following steps can be followed: first, cut the isolation film into a sample to be tested of a certain size (for example, 6mm ⁇ 6mm), clamp the sample to be tested with two sheets of electrically and thermally conductive sheets (such as copper foil), and place the sample to be tested.
  • Use glue such as double-sided tape
  • a certain mass such as about 400g
  • a certain time such as 1h
  • the sample stage into the sample holder and lock it, turn on the power of the argon ion cross-section polisher (such as IB-19500CP) and evacuate (such as 10Pa-4Pa), set the argon flow (such as 0.15MPa) and voltage (such as 8KV) ) and polishing time (such as 2 hours), adjust the sample stage to rocking mode to start polishing, and after polishing, use a scanning electron microscope (such as ZEISS Sigma 300) to obtain the ion-polished cross-sectional topography (CP) picture of the sample to be tested.
  • the argon ion cross-section polisher such as IB-19500CP
  • evacuate such as 10Pa-4Pa
  • the argon flow such as 0.15MPa
  • voltage such as 8KV
  • polishing time such as 2 hours
  • FIG. 2 is an ion-polished cross-sectional topography (CP) picture of the isolation film of the embodiment of the present application at a magnification of 3000 times.
  • the coating of the separator includes the first organic particles and the second organic particles; the first organic particles are secondary particles composed of multiple primary particles, and are irregular and non-solid. Spherical cross-section; the second organic particle is a non-agglomerated primary particle and is a solid spherical cross-section.
  • the species species of the organic particles can be tested using equipment and methods known in the art.
  • the infrared spectrum of a material can be tested to determine the characteristic peaks it contains, thereby identifying species.
  • the organic particles can be analyzed by infrared spectroscopy with instruments and methods known in the art, for example, an infrared spectrometer, such as an IS10 Fourier transform infrared spectrometer from Nicolet, USA, according to GB/T6040-2002 Infrared spectroscopy analysis method general test.
  • the volume-average particle size Dv50 of the inorganic particles is the meaning known in the art, and can be measured by using instruments and methods known in the art.
  • a laser particle size analyzer for example, Master Size 3000
  • the distance between any two adjacent inorganic particles refers to: in the SEM image of the isolation film, any two adjacent inorganic particles in the coating (when the inorganic particles are irregular in shape) , the particle can be circumscribed), and the distance between the centers of the two inorganic particles is measured as the distance between the two inorganic particles, and recorded as L1.
  • the distance between any adjacent one inorganic particle and one organic particle refers to: in the SEM image of the isolation film, any adjacent one inorganic particle and one organic particle in the coating (when the inorganic particle is When the particle or organic particle is of irregular shape, the particle can be circumscribed), and the distance between the center of the circle of the inorganic particle and the organic particle is measured as the distance between the inorganic particle and the organic particle, denoted as L2.
  • the above-mentioned organic particles can be either the first type of organic particles or the second type of organic particles.
  • the above spacing can be measured using instruments known in the art. For example, scanning electron microscopy can be used.
  • the test can refer to JY/T010-1996. Randomly select an area in the test sample for scanning test, and acquire an SEM image of the isolation film at a certain magnification (for example, 3000 times).
  • the particle When the organic particle is an irregular body, the particle can be circumscribed), and the distance between the center of the inorganic particle (or its circumcircle) and the center of the organic particle (or its circumcircle) is measured.
  • the distance between the adjacent inorganic particles and organic particles is denoted as L2.
  • multiple groups of adjacent particles for example, 10 groups
  • the distance L1 between any two adjacent inorganic particles can also be tested according to the above method.
  • FIG. 3 is a scanning electron microscope (SEM) picture of the isolation film of the embodiment of the present application under a magnification of 3000 times. It can be seen from FIG. 3 that the coating of the isolation film includes inorganic particles, first organic particles and second organic particles, the first organic particles are secondary particles, the second organic particles are primary particles, and the first organic particles are primary particles. One organic particle and a second organic particle are embedded in the inorganic particles and form protrusions on the surface of the coating. After measuring according to the method described above, it can be concluded that L1 ⁇ L2.
  • the air permeability, transverse tensile strength (MD), longitudinal tensile strength (TD), transverse elongation at break, and longitudinal elongation at break of the separator all have meanings known in the art, and can be used in the art. measured by known methods. For example, it can be tested with reference to the standard GB/T 36363-2018.
  • the present application also provides a method for preparing an isolation film, comprising the following steps:
  • step (3) coating the coating slurry described in step (2) on at least one side of the substrate described in step (1), forming a coating layer and drying to obtain the isolation film;
  • the separator includes a substrate and a coating provided on at least one surface of the substrate; the coating includes inorganic particles, first organic particles and second organic particles; the first organic particles The particles and the second organic particles are embedded in the inorganic particles and form protrusions on the surface of the coating; the number average particle size of the first organic particles is >10 ⁇ m, and the second organic particles The number average particle size is 2 ⁇ m-10 ⁇ m.
  • the release film includes a substrate (A) and a coating layer (B) provided on only one surface of the substrate (A).
  • the release film includes a substrate (A) and a coating layer (B), and the coating layer (B) is simultaneously provided on both surfaces of the substrate (A).
  • the material of the substrate is not particularly limited, and any known substrate with good chemical stability and mechanical stability can be selected, such as glass fiber, non-woven fabric, polyethylene, polyethylene One or more of propylene and polyvinylidene fluoride.
  • the substrate can be a single-layer film or a multi-layer composite film.
  • the materials of each layer can be the same or different.
  • the solvent in step (2), may be water, such as deionized water.
  • the component material may also include other organic compounds, for example, may also include polymers that improve heat resistance, dispersants, wetting agents, other types of binding agents agent. Among them, other organic compounds are all non-particulate in the dried coating.
  • step (2) the component materials are added to the solvent and stirred uniformly to obtain a coating slurry.
  • the added mass of the first organic particles accounts for more than 12% of the total dry weight of the component materials; for example, 12%-30%, 15%-30% , 15%-25%, 15%-20%, 16%-22%.
  • the added mass of the second organic particles accounts for less than 10% of the total dry weight of the component materials, such as 2%-10%, 3%-7% , 3%-5%.
  • Appropriate content of organic particles can reduce the static electricity generated between the separator and the battery winding tool (such as rolling pin) or lamination tool during the battery preparation process, effectively reducing the probability of short circuit between the positive and negative electrodes, thereby improving the manufacturing efficiency of the battery. Rate.
  • the dry weight of the component material is the added mass of the component material.
  • the dry weight of the component material is the product of the added mass of the component material and the solid content of the component material.
  • the sum of the dry weights of the component materials is the sum of the dry weights of the respective component materials.
  • the solid content of the coating slurry may be controlled at 28%-45%, for example, may be 30%-38% by weight.
  • the solid content of the coating slurry is within the above range, the film surface problem of the coating and the probability of uneven coating can be effectively reduced, thereby further improving the cycle performance and safety performance of the battery.
  • step (3) the coating is performed using a coater.
  • the coating in step (3), may adopt a process such as transfer coating, spin spraying, dip coating, etc.; for example, the coating adopts transfer coating.
  • the coater includes a gravure roll; the gravure roll is used to transfer the coating slurry to the substrate.
  • the line count of the gravure roll may be 100LPI-300LPI, eg, 125LPI-190LPI (LPI is lines/inch).
  • LPI is lines/inch.
  • the coating speed in step (3), can be controlled at 30m/min-90m/min, such as 50m/min-70m/min.
  • the coating speed is within the above range, the film surface problem of the coating can be effectively reduced, and the probability of uneven coating can be reduced, thereby further improving the cycle performance and safety performance of the battery.
  • the line speed ratio of the coating in step (3), can be controlled at 0.8-2.5, for example, can be 0.8-1.5, 1.0-1.5.
  • the drying temperature may be 40°C-70°C, for example, 50°C-60°C.
  • the drying time may be 10s-120s, for example, may be 20s-80s, 20s-40s.
  • Controlling the above process parameters within the given ranges can further improve the performance of the isolation film of the present application.
  • Those skilled in the art can selectively adjust one or more of the above-mentioned process parameters according to the actual production situation.
  • the inorganic particles and the organic particles may also optionally satisfy one or more of the aforementioned parameter conditions. It will not be repeated here.
  • the above-mentioned substrates, the first organic particles and the second organic particles are all commercially available.
  • the coating is obtained by one-time coating, which greatly simplifies the production process of the separator; at the same time, the use of the separator prepared by the above method in the battery can effectively improve the cycle performance and safety of the battery performance.
  • the positive electrode sheet generally includes a positive electrode current collector and a positive electrode film layer disposed on the positive electrode current collector, and the positive electrode film layer includes a positive electrode active material.
  • the positive electrode current collector can be a conventional metal foil or a composite current collector (a metal material can be arranged on a polymer substrate to form a composite current collector).
  • the positive electrode current collector may use aluminum foil.
  • the specific type of the positive electrode active material is not limited, and active materials known in the art that can be used for the positive electrode of a secondary battery can be used, and those skilled in the art can select them according to actual needs.
  • the positive active material may include, but is not limited to, one or more of lithium transition metal oxides, olivine-structured lithium-containing phosphates and their respective modified compounds.
  • lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide One or more of lithium nickel cobalt aluminum oxide and its modified compounds.
  • olivine-structured lithium-containing phosphates may include, but are not limited to, lithium iron phosphate, composites of lithium iron phosphate and carbon, lithium manganese phosphate, composites of lithium manganese phosphate and carbon, lithium iron manganese phosphate, lithium iron manganese phosphate One or more of the composite materials with carbon and their modified compounds. These materials are all commercially available.
  • the modification compound of each of the above materials may be doping modification and/or surface coating modification of the material.
  • the positive electrode film layer usually optionally includes a binder, a conductive agent and other optional auxiliary agents.
  • the conductive agent may be one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, Super P(SP), graphene and carbon nanofibers.
  • the binder may be styrene-butadiene rubber (SBR), water-based acrylic resin, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer One or more of (EVA), polyacrylic acid (PAA), carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA) and polyvinyl butyral (PVB).
  • SBR styrene-butadiene rubber
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • EVA ethylene-vinyl acetate copolymer
  • PAA polyacrylic acid
  • CMC carboxymethyl cellulose
  • PVA polyvinyl alcohol
  • PVB polyvinyl butyral
  • the negative electrode sheet generally includes a negative electrode current collector and a negative electrode film layer disposed on the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material.
  • the negative electrode current collector can be a conventional metal foil or a composite current collector (for example, a metal material can be arranged on a polymer substrate to form a composite current collector).
  • the negative electrode current collector may use copper foil.
  • the negative electrode active materials are not limited, and active materials known in the art that can be used for secondary battery negative electrodes can be used, and those skilled in the art can select them according to actual needs.
  • the negative electrode active material may include, but is not limited to, one or more of artificial graphite, natural graphite, hard carbon, soft carbon, silicon-based materials and tin-based materials.
  • the silicon-based material may be selected from one or more of elemental silicon, silicon-oxygen compounds (eg, silicon oxide), silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.
  • the tin-based material can be selected from one or more of elemental tin, tin oxide compounds, and tin alloys. These materials are all commercially available.
  • the anode active material may include a silicon-based material.
  • the negative electrode film layer usually optionally includes a binder, a conductive agent and other optional auxiliary agents.
  • the conductive agent may be one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • the binder may be styrene-butadiene rubber (SBR), water-based acrylic resin, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer One or more of (EVA), polyvinyl alcohol (PVA) and polyvinyl butyral (PVB).
  • SBR styrene-butadiene rubber
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • EVA ethylene-vinyl acetate copolymer
  • EVA polyvinyl alcohol
  • PVB polyvinyl butyral
  • other optional adjuvants may be thickening and dispersing agents (eg, sodium carboxymethyl cellulose CMC-Na), PTC thermistor materials, and the like.
  • the secondary battery may include an electrolyte that functions to conduct ions between the positive electrode and the negative electrode.
  • the electrolytic solution may include an electrolyte salt and a solvent.
  • the electrolyte salt may be selected from lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bisfluorosulfonimide (LiFSI), Lithium Trifluoromethanesulfonimide (LiTFSI), Lithium Trifluoromethanesulfonate (LiTFS), Lithium Difluorooxalate Borate (LiDFOB), Lithium Dioxalate Borate (LiBOB), Lithium Difluorophosphate (LiPO2F2), Difluorodifluorodicarbonate One or more of lithium oxalate phosphate (LiDFOP) and lithium tetrafluorooxalate phosphate (LiTFOP).
  • LiPF6 lithium hexafluorophosphate
  • the solvent may be selected from ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), carbonic acid Dipropyl (DPC), Methyl Propyl Carbonate (MPC), Ethyl Propyl Carbonate (EPC), Butylene Carbonate (BC), Fluoroethylene Carbonate (FEC), Methyl Formate (MF), Methyl Acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), One or more of ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS) and diethyl s
  • additives are also included in the electrolyte.
  • the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain performance of the battery, such as additives to improve battery overcharge performance, additives to improve battery high temperature performance, and additives to improve battery low temperature performance. additives, etc.
  • the secondary battery may be a lithium-ion secondary battery.
  • FIG. 5 is a secondary battery 5 of a square structure as an example.
  • the secondary battery may include an outer package.
  • the outer package is used to encapsulate the positive pole piece, the negative pole piece and the electrolyte.
  • the outer package may include a housing 51 and a cover 53 .
  • the housing 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate are enclosed to form a accommodating cavity.
  • the housing 51 has an opening that communicates with the accommodating cavity, and a cover plate 53 can cover the opening to close the accommodating cavity.
  • the positive pole piece, the negative pole piece and the separator may be formed into the electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the receiving cavity.
  • the electrolyte can be an electrolytic solution, and the electrolytic solution is infiltrated in the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the secondary battery 5 may be one or several, and may be adjusted according to requirements.
  • the outer packaging of the secondary battery may be a hard case, such as a hard plastic case, an aluminum case, a steel case, and the like.
  • the outer package of the secondary battery may also be a soft package, such as a pouch-type soft package.
  • the material of the soft bag may be plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), and the like.
  • the secondary batteries can be assembled into a battery module, and the number of secondary batteries contained in the battery module can be multiple, and the specific number can be adjusted according to the application and capacity of the battery module.
  • FIG. 7 shows the battery module 4 as an example.
  • the plurality of secondary batteries 5 may be arranged in sequence along the longitudinal direction of the battery module 4 .
  • the plurality of secondary batteries 5 can be fixed with fasteners.
  • the battery module 4 may further include a housing having an accommodating space in which the plurality of secondary batteries 5 are accommodated.
  • the above-mentioned battery modules can also be assembled into a battery pack, and the number of battery modules included in the battery pack can be adjusted according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery case and a plurality of battery modules 4 disposed in the battery case.
  • the battery box includes an upper box body 2 and a lower box body 3 .
  • the upper box body 2 can cover the lower box body 3 and form a closed space for accommodating the battery module 4 .
  • the plurality of battery modules 4 may be arranged in the battery case in any manner.
  • the present application also provides a device comprising at least one of the secondary battery, the battery module, or the battery pack.
  • the secondary battery, battery module or battery pack can be used as a power source of the device, and can also be used as an energy storage unit of the device.
  • the device may be, but is not limited to, mobile devices (eg, cell phones, laptops, etc.), electric vehicles (eg, pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf balls) vehicles, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • the device may select a secondary battery, a battery module or a battery pack according to its usage requirements.
  • Figure 10 is an apparatus as an example.
  • the device is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or the like.
  • a battery pack or a battery module can be employed.
  • the device may be a mobile phone, a tablet computer, a laptop computer, and the like.
  • the device is generally required to be thin and light, and a secondary battery can be used as a power source.
  • the thickness of the substrate is 7 ⁇ m and the porosity is 40%;
  • the volume average particle size Dv50 of the inorganic particles Al2O3 is 1 ⁇ m
  • the first organic particles are secondary particles and the number average particle size is 15 ⁇ m
  • the second organic particles are primary particles and the number average particle size is 15 ⁇ m.
  • the average particle size was 2 ⁇ m.
  • step (3) Coat the coating slurry prepared in step (2) on the two surfaces of the PE substrate with a coater, and obtain a separator 1 through processes such as drying and slitting.
  • the number of lines of the gravure roll of the coating machine is 125LPI
  • the coating speed is 50m/min
  • the coating line speed ratio is 1.15
  • the drying temperature is 50°C
  • the drying time is 25s
  • the single-sided coating weight was 2.3 g/m 2 .
  • the substrate can be purchased from Shanghai Enjie New Materials Co., Ltd.
  • Inorganic particles can be purchased from One Stone Material Technology Co., Ltd.
  • the first organic particles can be purchased from Arkema (Changshu) Chemical Co., Ltd.
  • the second type of organic particles can be purchased from Sichuan Indile Technology Co., Ltd.
  • the dispersant can be purchased from Changshu Weiyi Technology Co., Ltd.
  • Wetting agents are available from The Dow Chemical Company.
  • the isolation film 2-31 is similar to the preparation method of the isolation film 1, and the difference is: the material types of the first organic particles and the second organic particles, and the number average of the first organic particles and the second organic particles are adjusted. Particle size, see Table 1 for details.
  • the positive active material LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523), the conductive agent carbon black (Super P), and the binder polyvinylidene fluoride (PVDF) were prepared in a mass ratio of 96.2:2.7:1.1 in an appropriate amount of solvent N- Methylpyrrolidone (NMP) is mixed evenly to obtain a positive electrode slurry, the positive electrode slurry is coated on the positive electrode current collector aluminum foil, and the positive electrode sheet is obtained by drying, cold pressing, slitting, cutting and other processes.
  • the positive electrode surface density was 0.207 mg/mm 2
  • the compacted density was 3.5 g/cm 3 .
  • the negative active material artificial graphite, conductive agent carbon black (Super P), binder styrene-butadiene rubber (SBR) and sodium carboxymethyl cellulose (CMC-Na) were mixed in an appropriate amount in a mass ratio of 96.4:0.7:1.8:1.1.
  • the solvent is evenly mixed with deionized water to obtain a negative electrode slurry, which is coated on the copper foil of the negative electrode current collector, and is obtained by drying, cold pressing, slitting, cutting and other processes to obtain a negative electrode pole piece.
  • the negative electrode surface density was 0.126 mg/mm 2
  • the compacted density was 1.7 g/cm 3 .
  • the separator 1 prepared above was used as the separator.
  • Ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed in a mass ratio of 30:70 to obtain an organic solvent, and the fully dried electrolyte salt LiPF 6 is dissolved in the above mixed solvent, and the concentration of the electrolyte salt is 1.0 mol/L, and the electrolyte is obtained after mixing evenly.
  • the secondary batteries prepared in the examples and comparative examples were charged at a constant current rate of 1C to a charge cut-off voltage of 4.2V, and then charged at a constant voltage to a current of ⁇ 0.05C, left for 30 minutes, and then charged at a constant rate of 0.33C.
  • the secondary batteries prepared in the examples and comparative examples were charged at a constant current rate of 1C to a charge cut-off voltage of 4.2V, and then charged at a constant voltage to a current of ⁇ 0.05C, left standing for 30 minutes, and then charged at a constant rate of 0.33C.
  • the battery was charged and discharged for 1500 cycles, and the battery capacity at this time was recorded as C1.
  • the secondary batteries prepared in the examples and comparative examples were charged at a constant current rate of 1C to a charge cut-off voltage of 4.2V, and then charged at a constant voltage to a current of ⁇ 0.05C, and allowed to stand for 10 minutes; then a piece was placed on the battery surface.
  • Metal heating plate tighten the battery with a clamp at the position where the battery does not contact the heating plate, and add a 3mm thermal insulation pad between the clamp and the battery, and heat it at a constant temperature of 200 °C until the battery thermal runaway occurs; record the time when the battery thermal runaway occurs.
  • Table 1 shows the measured battery performance of each of the Examples and Comparative Examples.
  • the cycle performance and safety performance of the battery can be significantly improved.
  • the cycle performance and safety performance of the battery can be further improved by further optimizing the number average particle size, number average particle size ratio or substance type of the first organic particle and the second organic particle.
  • Comparative Examples 1 and 5 using only the first organic particles are inferior to Examples 1-25 of the present application in terms of cycle performance and safety performance; Comparative Examples 2-4 and 6 use the first organic particles at the same time particles and the second organic particles, but at least one of the number-average particle diameter of the first organic particles and the number-average particle diameter of the second organic particles is not within the scope of this application, which is in terms of cycle performance and safety performance Although it is slightly better than Comparative Examples 1 and 5, it still cannot achieve the same degree of improvement as Examples 1-25 of the present application.
  • the inventors also conducted experiments with inorganic particles, other amounts and materials of the first organic particles and the second organic particles, other substrates, other coating process parameters and other drying conditions within the scope of the present application, and obtained the results.
  • the effect of improving the cycle performance and safety performance of the battery was similar to that of Examples 1-25.

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Abstract

一种隔离膜以及包括所述隔离膜的二次电池、包括所述二次电池的装置以及所述隔离膜的制备方法。所述隔离膜包括基材（A）和形成在所述基材（A）至少一个表面上的涂层（B），所述涂层（B）包括无机颗粒（B3）和有机颗粒，所述有机颗粒包括第一种有机颗粒（B1）和第二种有机颗粒（B2）；所述第一种有机颗粒（B1）和所述第二种有机颗粒（B2）嵌于所述无机颗粒（B3）中且在所述涂层（B）表面形成凸起；所述第一种有机颗粒（B1）的数均粒径＞10μm，且所述第二种有机颗粒（B2）的数均粒径为2μm-10μm。

Description

一种隔离膜、其制备方法及其相关的二次电池、电池模块、电池包和装置 技术领域
本申请属于二次电池技术领域，具体涉及一种隔离膜、含有它的二次电池及其相关的电池模块、电池包和装置。
背景技术
二次电池因具有重量轻、无污染、无记忆效应等突出特点，被广泛应用于各类消费类电子产品和电动车辆中。
随着新能源行业的不断发展，客户对二次电池提出了更高的使用需求。例如，二次电池的能量密度设计越来越高，然而，电池能量密度的提升往往不利于平衡动力学性能、电化学性能或安全性能等。
因此，如何使电池可以同时兼顾循环性能、安全性能是电池设计领域的关键挑战所在。
发明内容
鉴于上述存在的技术问题，本申请的第一方面提供一种隔离膜，旨在使含有该隔离膜的二次电池可以同时兼顾较好的循环性能和安全性能。
为了实现上述目的，本申请第一方面的隔离膜包括：基材和形成在所述基材至少一个表面上的涂层。所述涂层包括无机颗粒和有机颗粒。所述有机颗粒包括第一种有机颗粒和第二种有机颗粒。所述第一种有机颗粒和所述第二种有机颗粒嵌于所述无机颗粒中且在所述涂层表面形成凸起。所述第一种有机颗粒的数均粒径＞10μm，且所述第二种有机颗粒的数均粒径为2μm-10μm。
相对于现有技术，本申请至少包括如下所述的有益效果：
本申请的隔离膜在同一涂层中含有无机颗粒和有机颗粒，与具有无机颗粒层和有机颗粒层两个涂层的隔离膜相比，大大减小了隔离膜的厚度，从而提高电池的能量密度；且所述有机颗粒包括特定粒径的第一种有机颗粒和第二种有机颗粒，与只包括一种有机颗粒的情况相比，使得二次电池在正常工作时，能够在有机颗粒、无机颗粒之间形成充足且不均匀分布的空隙，保证离子传输通道的畅通，从而使电池具有良好的循环性能； 同时，二次电池处于高温工作时，第一种及第二种有机颗粒能够形成大面积的胶膜结构以减少或阻隔离子传输通道，延缓电池的热蔓延，从而使电池获得良好的安全性能。
在本申请任意实施方式中，所述第一种有机颗粒的数均粒径可以为12μm-25μm；可选地，所述第一种有机颗粒的数均粒径为15μm-20μm。当第一种有机颗粒的数均粒径在所给范围内时，能够进一步改善电池的循环性能。
在本申请任意实施方式中，所述第二种有机颗粒的数均粒径可以为2μm-8μm；可选地，所述第二种有机颗粒的数均粒径为3μm-7μm。当第二种有机颗粒的数均粒径在所给范围内时，能够进一步改善电池的循环性能和安全性能。
在本申请任意实施方式中，所述第一种有机颗粒的数均粒径与所述第二种有机颗粒的数均粒径的比值≥1.5；可选地，所述第一种有机颗粒的数均粒径与所述第二种有机颗粒的数均粒径的比值≥2.0。当第一种有机颗粒的数均粒径与第二种有机颗粒的数均粒径的比值在所给范围内时，能够进一步改善电池的循环性能和安全性能。
在本申请任意实施方式中，所述第一种有机颗粒为二次颗粒。当第一种有机颗粒为二次颗粒时，能够进一步改善电池的安全性能。
在本申请任意实施方式中，所述第二种有机颗粒为一次颗粒。当第二种有机颗粒为一次颗粒时，能够进一步改善电池的循环性能和安全性能。
在本申请任意实施方式中，单位面积的隔离膜上的单面涂层重量≤3.0g/m 2；可选地，单位面积的隔离膜上的单面涂层重量为1.5g/m 2-2.5g/m 2。当单位面积的隔离膜上的单面涂层重量在所给范围内时，能够在确保电池循环性能和安全性能的前提下，进一步提高电池的能量密度。
在本申请任意实施方式中，无机颗粒的体积平均粒径Dv50≤2.5μm；可选地，无机颗粒的体积平均粒径Dv50为0.5μm-2.5μm。当无机颗粒的体积平均粒径Dv50在所给范围内时，能够确保隔离膜在较好的循环性能和安全性能的前提下，进一步提高电池的体积能量密度。
在本申请任意实施方式中，所述无机颗粒在所述涂层中的质量百分比≤70％，可选地，所述无机颗粒在所述涂层中的质量百分比为60％-70％。当无机颗粒的质量占比控制在所给范围内时，可以确保隔离膜安全性能的前提下，进一步提高电池的质量能量密度。
在本申请任意实施方式中，所述第一种有机颗粒在所述涂层中的质量百分比≥12％，可选地，所述第一种有机颗粒在所述涂层中的质量百分比为15％-25％。当第一种有机颗 粒的质量占比控制在所给范围内时，可以改善电池的循环性能和安全性能。
在本申请任意实施方式中，所述第二种有机颗粒在所述涂层中的质量百分比≤10％，可选地，所述第二种有机颗粒在所述涂层中的质量百分比为2％-10％。当第二种有机颗粒的质量占比控制在所给范围内时，可以改善电池的循环性能和安全性能。
通过选择适当的无机颗粒、第一种有机颗粒和第二种有机颗粒含量，可以使三者发挥更好的协同作用，确保隔离膜的安全性能并改善电池的能量密度。
在本申请任意实施方式中，所述第一种有机颗粒可以包括含氟烯基单体单元的均聚物或共聚物，烯烃基单体单元的均聚物或共聚物，不饱和腈类单体单元的均聚物或共聚物，环氧烷类单体单元的均聚物或共聚物，以及上述各均聚物或共聚物的改性化合物中的一种或几种。
在本申请任意实施方式中，所述第一种有机颗粒可以包括聚四氟乙烯、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、含氟烯基单体单元与乙烯基单体单元的共聚物、含氟烯基单体单元与丙烯酸类单体单元的共聚物、含氟烯基单体单元与丙烯酸酯类单体单元的共聚物，以及上述各均聚物或共聚物的改性化合物中的一种或几种。
在本申请任意实施方式中，所述第一种有机颗粒可以包括偏二氟乙烯-三氟乙烯共聚物、偏二氟乙烯-六氟丙烯共聚物、偏二氟乙烯-三氟乙烯-六氟丙烯共聚物、偏二氟乙烯-六氟丙烯-丙烯酸共聚物、偏二氟乙烯-六氟丙烯-丙烯酸酯共聚物，以及上述共聚物的改性化合物中的一种或几种。
在本申请任意实施方式中，所述第二种有机颗粒可以包括丙烯酸酯类单体单元的均聚物或共聚物，丙烯酸类单体单元的均聚物或共聚物，苯乙烯类单体单元的均聚物或共聚物，聚氨酯类化合物，橡胶类化合物，以及上述各均聚物或共聚物的改性化合物中的一种或几种。
可选地，所述第二种有机颗粒可以包括丙烯酸酯类单体单元与苯乙烯类单体单元的共聚物，丙烯酸类单体单元与苯乙烯类单体单元的共聚物，丙烯酸类单体单元-丙烯酸酯类单体单元-苯乙烯类单体单元的共聚物，苯乙烯类单体单元与不饱和腈类单体单元的共聚物，苯乙烯类单体单元-烯烃基单体单元-不饱和腈类单体单元的共聚物，以及上述共聚物的改性化合物中的一种或几种。
在本申请任意实施方式中，所述第二种有机颗粒可以包括丙烯酸丁酯-苯乙烯共聚 物、甲基丙烯酸丁酯-甲基丙烯酸异辛酯共聚物、甲基丙烯酸异辛酯-苯乙烯共聚物、甲基丙烯酸酯-甲基丙烯酸-苯乙烯共聚物、丙烯酸甲酯-甲基丙烯酸异辛酯-苯乙烯共聚物、丙烯酸丁酯-丙烯酸异辛酯-苯乙烯共聚物、丙烯酸丁酯-甲基丙烯酸异辛酯-苯乙烯共聚物、甲基丙烯酸丁酯-丙烯酸异辛酯-苯乙烯共聚物、甲基丙烯酸丁酯-甲基丙烯酸异辛酯-苯乙烯共聚物、苯乙烯-丙烯腈共聚物、苯乙烯-丁二烯-丙烯腈共聚物、丙烯酸甲酯-苯乙烯-丙烯腈共聚物、甲基丙烯酸异辛酯-苯乙烯-丙烯腈共聚物、苯乙烯-醋酸乙烯酯共聚物，苯乙烯-醋酸乙烯酯-吡咯烷酮共聚物，以及上述共聚物的改性化合物中的一种或几种。
在本申请任意实施方式中，无机颗粒可以包括勃姆石(γ-AlOOH)、氧化铝(Al 2O 3)、硫酸钡(BaSO 4)、氧化镁(MgO)、氢氧化镁(Mg(OH) 2)、二氧化硅(SiO 2)、二氧化锡(SnO 2)、氧化钛(TiO 2)、氧化钙(CaO)、氧化锌(ZnO)、氧化锆(ZrO 2)、氧化钇(Y 2O 3)、氧化镍(NiO)、氧化铈(CeO 2)、钛酸锆(SrTiO 3)、钛酸钡(BaTiO 3)、氟化镁(MgF 2)中的一种或几种。
在本申请任意实施方式中，所述隔离膜的透气度可以为100s/100mL-300s/100mL；可选地，所述隔离膜的透气度可以为150s/100mL-250s/100mL。
在本申请任意实施方式中，所述隔离膜的横向拉伸强度(MD)可以为1500kgf/cm 2-3000kgf/cm 2；可选地，所述隔离膜的横向拉伸强度可以为1800kgf/cm 2-2500kgf/cm 2。
在本申请任意实施方式中，所述隔离膜的纵向拉伸强度(TD)可以为1000kgf/cm 2-2500kgf/cm 2；可选地，所述隔离膜的纵向拉伸强度可以为1400kgf/cm 2-2000kgf/cm 2。
在本申请任意实施方式中，所述隔离膜的横向断裂伸长率可以为50％-200％；可选地，所述隔离膜的横向断裂伸长率可以为100％-150％。
在本申请任意实施方式中，所述隔离膜的纵向断裂伸长率可以为50％-200％；可选地，所述隔离膜的纵向断裂伸长率可以为100％-150％。
在本申请任意实施方式中，所述无机颗粒和所述有机颗粒在涂层中形成不均匀的孔道结构。
在本申请任意实施方式中，任意相邻的两个无机颗粒之间的间距记为L1，任意相邻的一个无机颗粒和一个有机颗粒之间的间距记为L2，则L1＜L2。
本申请的第二方面提供一种制备隔离膜的方法，包括如下步骤：
(1)提供基材。(2)提供涂层浆料，所述涂层浆料包括组分材料和溶剂，所述组分材料包括无机颗粒和有机颗粒，所述有机颗粒包括第一种有机颗粒和第二种有机颗粒。(3)将步骤(2)所述的涂层浆料涂布在步骤(1)所述的基材的至少一侧，形成涂层并干燥，得到所述隔离膜。其中，干燥后的涂层包括所述无机颗粒、所述第一种有机颗粒和所述第二种有机颗粒。所述第一种有机颗粒和所述第二种有机颗粒嵌于所述无机颗粒中且在所述干燥后的涂层表面形成凸起。所述第一种有机颗粒的数均粒径＞10μm，且所述第二种有机颗粒的数均粒径为2μm-10μm。
在本申请任意实施方式中，在步骤(2)中，所述第一种有机颗粒的加入质量占所述组分材料的干重总和的12％以上；可选为12％-30％。
在本申请任意实施方式中，在步骤(2)中，所述第二种有机颗粒的加入质量占所述组分材料的干重总和的10％以下，可选为2％-10％。
在本申请任意实施方式中，在步骤(2)中，所述涂层浆料的固含量为28％-45％，可选为30％-38％，基于重量计。
在本申请任意实施方式中，在步骤(3)中，所述涂布采用涂布机，所述涂布机包括凹版辊，所述凹版辊的线数为100LPI-300LPI，可选为125LPI-190LPI。
在本申请任意实施方式中，在步骤(3)中，所述涂布的速度为30m/min-90m/min，可选为50m/min-70m/min。
在本申请任意实施方式中，在步骤(3)中，所述涂布的线速比为0.8-2.5，可选为0.8-1.5。
在本申请任意实施方式中，在步骤(3)中，所述干燥的温度为40℃-70℃，可选为50℃-60℃。
在本申请任意实施方式中，在步骤(3)中，所述干燥的时间为10s-120s，可选为20s-80s。
本申请的第三方面提供一种二次电池，其包括根据本申请第一方面的隔离膜或包括根据本申请第二方面的方法制备的隔离膜。
本申请的第四方面提供一种电池模块，其包括根据本申请第三方面的二次电池。
本申请的第五方面提供一种电池包，其包括根据本申请第四方面的电池模块。
本申请的第六方面提供一种装置，其包括根据本申请第三方面的二次电池、根据本 申请第四方面的电池模块、或根据本申请第五方面的电池包中的至少一种。
附图说明
为了更清楚地说明本申请的技术方案，下面将对本申请中所使用的附图作简单介绍。显而易见地，下面所描述的附图仅仅是本申请的一些实施方式，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
图1是本申请隔离膜的一实施方式的结构示意图。
图2是本申请隔离膜的一实施方式在3000倍放大倍率下的离子抛光断面形貌(CP)图片。
图3是本申请隔离膜的一实施方式的在3000倍放大倍率下的扫描电子显微镜(SEM)图片。
图4-1是本申请隔离膜的一实施方式的结构示意图。
图4-2是本申请隔离膜的另一实施方式的结构示意图。
图5是二次电池的一实施方式的示意图。
图6是图5的分解图。
图7是电池模块的一实施方式的示意图。
图8是电池包的一实施方式的示意图。
图9是图8的分解图。
图10是二次电池用作电源的装置的一实施方式的示意图。
具体实施方式
下面结合具体实施方式，进一步阐述本申请。应理解，这些具体实施方式仅用于说明本申请而不用于限制本申请的范围。
为了简明，本文仅具体地公开了一些数值范围。然而，任意下限可以与任意上限组合形成未明确记载的范围；以及任意下限可以与其它下限组合形成未明确记载的范围，同样任意上限可以与任意其它上限组合形成未明确记载的范围。此外，每个单独公开的点或单个数值自身可以作为下限或上限与任意其它点或单个数值组合或与其它下限或上限组合形成未明确记载的范围。
在本文的描述中，需要说明的是，除非另有说明，“以上”、“以下”为包括本数， “一种或几种”中“几种”的含义是两种及两种以上。
在本文的描述中，除非另有说明，术语“或(or)”是包括性的。也就是说，短语“A或(or)B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B都为真(或存在)。
除非另有说明，本申请中使用的术语具有本领域技术人员通常所理解的公知含义。除非另有说明，本申请中提到的各参数的数值可以用本领域常用的各种测量方法进行测量(例如，可以按照在本申请的实施例中给出的方法进行测试)。
二次电池
二次电池，是指在电池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，二次电池包括正极极片、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，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。
[隔离膜]
本申请提供的隔离膜包括：基材和形成在所述基材至少一个表面上的涂层。所述涂层包括无机颗粒和有机颗粒。所述有机颗粒包括第一种有机颗粒和第二种有机颗粒，所述第一种有机颗粒和所述第二种有机颗粒嵌于所述无机颗粒中且在所述涂层表面形成凸起。所述第一种有机颗粒的数均粒径＞10μm，且所述第二种有机颗粒的数均粒径为2μm-10μm。
需要说明的是，所述有机颗粒的数均粒径是指在隔离膜涂层中，按有机颗粒数量统计的有机颗粒的粒径的算术平均值。所述有机颗粒的粒径是指有机颗粒上相隔最远的两点间的距离。
不希望限于任何理论，本申请的隔离膜在同一涂层中包含无机颗粒和有机颗粒，与具有无机颗粒层和有机颗粒层两个涂层的隔离膜相比，大大减小了隔离膜的整体厚度，从而提高了电池的能量密度；且有机颗粒中包括特定数均粒径及结构设计的第一种有机颗粒和第二种有机颗粒，在二者的相互配合下，电池可以同时兼顾较好的循环性能和安全性能。本申请的隔离膜中，特定粒径范围的第一种有机颗粒和第二种有机颗粒联合使用，当电池在正常工作环境(例如45℃以下)时，将二者搭配使用可以有效降低涂层中 的有机颗粒在电解液中被溶胀后形成致密且面积较大的胶膜的几率，使得隔离膜涂层中具有适度的不均匀的孔道结构，便于活性离子的传输，从而有效改善电池的循环性能；特别地，当电池处于高温工作环境中(例如100℃以上)时，特定粒径的第一种有机颗粒和第二种有机颗粒在高温下会形成大面积的胶膜结构，快速减少活性离子的扩散通道，延缓热蔓延的时间，从而有效改善电池的安全性能。
本申请人经深入研究发现，当本申请的隔离膜在满足上述设计条件的基础上，若还可选地满足下述条件中的一个或几个时，可以进一步改善二次电池的性能。
在一些实施方式中，所述第一种有机颗粒的数均粒径为12μm-25μm；例如，所述第一种有机颗粒的数均粒径可以为15μm-25μm，12μm-23μm，13μm-22μm，15μm-20μm，12μm-18μm等。当第一种有机颗粒的数均粒径在所给范围内时，能够使有机颗粒间存在充足的空隙，即使有机颗粒在电解液中发生溶胀，也能够形成充足的离子传输通道，从而进一步改善电池的循环性能。
在一些实施方式中，所述第二种有机颗粒的数均粒径可以为2μm-9μm；例如，第二种有机颗粒的数均粒径可以为2μm-8μm，2.5μm-7μm，2.5μm-5μm，3μm-7μm，2μm-6μm，3μm-5.5μm等。发明人研究发现，当第二种有机颗粒的数均粒径在所给范围内时，能够进一步改善电池的循环性能和安全性能。第二种有机颗粒的数均粒径如果过小(例如小于2μm)，其在电解液中容易溶胀形成胶膜结构，在电池正常工作时，会阻隔离子传输通道，从而影响电池的循环性能；第二种有机颗粒的数均粒径如果过大(例如大于10μm)，其在电池制备的热压过程后，可能造成隔离膜与电极极片之间过牢固粘接，导致电解液的浸润不良，从而影响电池的循环性能。
在一些实施方式中，所述第一种有机颗粒的数均粒径与所述第二种有机颗粒的数均粒径的比值≥1.5；例如，所述第一种有机颗粒的数均粒径与所述第二种有机颗粒的数均粒径的比值可以为1.5～5，2～4，2.5～3.5，2.5～5.5，3～4.5，3～4等。通过选择二者合适的数均粒径比值，能够进一步改善电池的循环性能和安全性能。
根据一些实施例，所述第一种有机颗粒为二次颗粒。当隔离膜涂层中包括二次颗粒形貌的第一种有机颗粒时，有助于形成均匀的涂层界面，当将隔离膜用到电池后，可以有效改善电池制备过程中的极耳错位问题，从而进一步改善电池的安全性能。
根据一些实施例，所述第二种有机颗粒为一次颗粒。当隔离膜涂层中包括一次颗粒形貌的第二种有机颗粒时，颗粒与颗粒之间不容易形成大面积的胶膜结构，从而进一步 改善电池的循环性能和安全性能。在一些实施方式中，第一种有机颗粒起到用于制造间隙的作用；第二种有机颗粒起到增强隔离膜与电极极片(例如正极极片或负极极片)之间的粘结力的作用。
需要说明的是，一次颗粒及二次颗粒具有本领域公知的含义。一次颗粒是指没有形成团聚状态的颗粒。二次颗粒是指由两个或两个以上一次颗粒聚集而成的团聚态的颗粒。
如图1所示，所述隔离膜包括基材(A)和涂层(B)，所述涂层(B)中包括第一种有机颗粒(B1)、第二种有机颗粒(B2)和无机颗粒(B3)，第一种有机颗粒(B1)为二次颗粒，第二种有机颗粒(B2)为一次颗粒，第一种有机颗粒和第二种有机颗粒均嵌于所述无机颗粒(B3)中且在所述涂层(B)表面形成凸起。
在一些实施方式中，所述第一种有机颗粒可以包括含氟烯基单体单元的均聚物或共聚物，烯烃基单体单元的均聚物或共聚物，不饱和腈类单体单元的均聚物或共聚物，环氧烷类单体单元的均聚物或共聚物，以及上述各均聚物或共聚物的改性化合物中的一种或几种。
在一些实施方式中，所述含氟烯基单体单元可选自二氟乙烯、偏二氟乙烯、三氟乙烯、三氟氯乙烯、四氟乙烯、六氟丙烯中的一种或几种。
在一些实施方式中，所述烯烃基单体单元可选自乙烯、丙烯、丁二烯、异戊二烯等中的一种或几种。
在一些实施方式中，所述不饱和腈类单体单元可选自丙烯腈、甲基丙烯腈等中的一种或几种。
在一些实施方式中，所述环氧烷类单体单元可选自环氧乙烷、环氧丙烷等中的一种或几种。
在一些实施方式中，所述第一种有机颗粒可以包括聚四氟乙烯、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、不同含氟烯基单体单元的共聚物、含氟烯基单体单元与烯烃基单体单元的共聚物、含氟烯基单体单元与丙烯酸类单体单元的共聚物、含氟烯基单体单元与丙烯酸酯类单体单元的共聚物，以及上述各均聚物或共聚物的改性化合物中的一种或几种。
在一些实施方式中，所述第一种有机颗粒可以包括偏二氟乙烯-三氟乙烯共聚物、偏二氟乙烯-六氟丙烯共聚物、偏二氟乙烯-三氟乙烯-六氟丙烯共聚物、偏二氟乙烯-六氟丙烯-丙烯酸共聚物、偏二氟乙烯-六氟丙烯-丙烯酸酯共聚物，以及上述共聚物的改 性化合物中的一种或几种。
在一些实施方式中，所述第二种有机颗粒可以包括丙烯酸酯类单体单元的均聚物或共聚物，丙烯酸类单体单元的均聚物或共聚物，苯乙烯类单体单元的均聚物或共聚物，聚氨酯类化合物，橡胶类化合物，以及上述各均聚物或共聚物的改性化合物中的一种或几种。
在一些实施方式中，所述第二种有机颗粒可以包括丙烯酸酯类单体单元与苯乙烯类单体单元的共聚物，丙烯酸类单体单元与苯乙烯类单体单元的共聚物，丙烯酸类单体单元-丙烯酸酯类单体单元-苯乙烯类单体单元的共聚物，苯乙烯类单体单元与不饱和腈类单体单元的共聚物，苯乙烯类单体单元-烯烃基单体单元-不饱和腈类单体单元的共聚物，以及上述各材料的改性化合物中的一种或几种。
在一些实施方式中，所述丙烯酸酯类单体单元可以选自丙烯酸甲酯、丙烯酸乙酯、丙烯酸丙酯、丙烯酸丁酯、甲基丙烯酸甲酯、甲基丙烯酸丁酯、甲基丙烯酸异辛酯等中的一种或几种。
在一些实施方式中，所述丙烯酸类单体单元可以选自丙烯酸、甲基丙烯酸等中的一种或几种。
在一些实施方式中，所述苯乙烯类单体单元可选自苯乙烯、甲基苯乙烯等中的一种或几种。
在一些实施方式中，所述不饱和腈类单体单元可选自丙烯腈、甲基丙烯腈等中的一种或几种。
在一些实施方式中，所述第二种有机颗粒可以包括丙烯酸丁酯-苯乙烯共聚物、甲基丙烯酸丁酯-甲基丙烯酸异辛酯共聚物、甲基丙烯酸异辛酯-苯乙烯共聚物、甲基丙烯酸酯-甲基丙烯酸-苯乙烯共聚物、丙烯酸甲酯-甲基丙烯酸异辛酯-苯乙烯共聚物、丙烯酸丁酯-丙烯酸异辛酯-苯乙烯共聚物、丙烯酸丁酯-甲基丙烯酸异辛酯-苯乙烯共聚物、甲基丙烯酸丁酯-丙烯酸异辛酯-苯乙烯共聚物、甲基丙烯酸丁酯-甲基丙烯酸异辛酯-苯乙烯共聚物、苯乙烯-丙烯腈共聚物、苯乙烯-丁二烯-丙烯腈共聚物、丙烯酸甲酯-苯乙烯-丙烯腈共聚物、甲基丙烯酸异辛酯-苯乙烯-丙烯腈共聚物、苯乙烯-醋酸乙烯酯共聚物，苯乙烯-醋酸乙烯酯-吡咯烷酮共聚物，以及上述各材料的改性化合物中的一种或几种。
根据一些实施例，所述各均聚物或共聚物的改性化合物是指将各均聚物或共聚物中 的单体单元与含有特定官能团的单体单元共聚所得的改性化合物。例如，可以将含氟烯基单体单元与含羧基官能团的化合物共聚得到其改性化合物等。
在一些实施方式中，第一种有机颗粒的数均分子量为30万-80万，例如40万-65万等。
在一些实施方式中，第二种有机颗粒的数均分子量为1万-10万，例如2万-8万等。
根据一些实施例，所述无机颗粒可以包括勃姆石(γ-AlOOH)、氧化铝(Al 2O 3)、硫酸钡(BaSO 4)、氧化镁(MgO)、氢氧化镁(Mg(OH) 2)、二氧化硅(SiO 2)、二氧化锡(SnO 2)、氧化钛(TiO 2)、氧化钙(CaO)、氧化锌(ZnO)、氧化锆(ZrO 2)、氧化钇(Y 2O 3)、氧化镍(NiO)、氧化铈(CeO 2)、钛酸锆(SrTiO 3)、钛酸钡(BaTiO 3)、氟化镁(MgF 2)中的一种或几种；例如，所述无机颗粒可以包括勃姆石(γ-AlOOH)、氧化铝(Al 2O 3)中的一种或几种。
在一些实施方式中，所述无机颗粒的体积平均粒径Dv50≤2.5μm；例如，所述无机颗粒的粒径可以为0.5μm-2.5μm，1.5μm-2.5μm，0.3μm-0.7μm等。当无机颗粒的粒径控制在所给范围内时，可以确保隔离膜在较好的循环性能和安全性能的前提下，进一步提高电池的体积能量密度。
在一些实施方式中，所述无机颗粒在所述涂层中的质量占比≤70％(基于所述涂层总质量计)；例如，所述无机颗粒在所述涂层中的质量占比可以为60％-70％，65％-70％等。当无机颗粒的质量占比控制在所给范围内时，可以确保隔离膜安全性能的前提下，进一步提高电池的质量能量密度。
在一些实施方式中，所述第一种有机颗粒在所述涂层中的质量占比≥12％(基于所述涂层总质量计)；例如，所述第一种有机颗粒在所述涂层中的质量占比可以为12％-30％，15％-30％，15％-25％，15％-20％等。当第一种有机颗粒的质量占比控制在所给范围内时，可以使隔离膜和极片在电池循环过程中有足够的应力释放空间，进一步改善电极极片的界面，同时，合适的质量占比范围还可以降低隔离膜对电解液的消耗量，从而进一步改善电池的循环性能和安全性能。
在一些实施方式中，所述第二种有机颗粒在所述涂层中的质量占比≤10％(基于所述涂层总质量计)；例如，所述第二种有机颗粒在所述涂层中的质量占比可以为2％-10％，3％-8％，4％-9％,5％-10％等。当第二种有机颗粒的质量占比控制在所给范围内时，有助于使隔离膜涂层在保证粘结性的前提下，具有合适的孔道结构，从而进一步改善电池的循 环性能和安全性能。
通过选择适当的无机颗粒、第一种有机颗粒和第二种有机颗粒含量，可以使三者发挥更好的协同作用，确保隔离膜在保证安全性能的前提下，还具有适当的孔道结构，同时实现隔离膜的轻质化，从而进一步改善电池的能量密度。
在一些实施方式中，单位面积的隔离膜上单面的涂层重量≤3.0g/m 2；例如，单位面积的隔离膜上单面的涂层重量可以为1.5g/m 2-3.0g/m 2，1.5g/m 2-2.5g/m 2，1.8g/m 2-2.3g/m 2等。将单位面积的隔离膜上单面的涂层重量控制在所给范围内，可以在确保电池循环性能和安全性能的前提下，进一步提高电池的能量密度。
根据一些实施例，所述涂层中还可以包括其他有机化合物，例如，可以包括改善耐热性的聚合物、分散剂、润湿剂、其他种类的粘结剂等。上述其他有机化合物在涂层中均为非颗粒状的物质。本申请对上述其他有机化合物的种类没有特别的限制，可以选用任意公知的具有良好改善性能的材料。
本申请对所述基材的材质没有特别的限制，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基材，例如玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏二氟乙烯中的一种或几种。所述基材可以是单层薄膜，也可以是多层复合薄膜。当所述基材为多层复合薄膜时，各层的材料可以相同，也可以不同。
在一些实施方式中，所述基材的厚度≤10μm；例如，所述基材的厚度可以为5μm-10μm，5μm-9μm，7μm-10μm等。所述基材的厚度控制在所给范围内时，可以在确保电池循环性能和安全性能的前提下，进一步提高电池能量密度。
在一些实施方式中，所述隔离膜的透气度可以为100s/100mL-300s/100mL；例如，所述隔离膜的透气度可以为150s/100mL-250s/100mL，170s/100mL-220s/100mL等。
在一些实施方式中，所述隔离膜的横向拉伸强度(MD)可以为1500kgf/cm 2-3000kgf/cm 2；例如，所述隔离膜的横向拉伸强度可以为1800kgf/cm 2-2500kgf/cm 2等。
在一些实施方式中，所述隔离膜的纵向拉伸强度(TD)可以为1000kgf/cm 2-2500kgf/cm 2；例如，可以为1400kgf/cm 2-2000kgf/cm 2等。
在一些实施方式中，所述隔离膜的横向断裂伸长率可以为50％-200％；例如，所述隔离膜的横向断裂伸长率可以为100％-150％。
在一些实施方式中，所述隔离膜的纵向断裂伸长率可以为50％-200％；例如，所述隔 离膜的纵向断裂伸长率可以为100％-150％。
在一些实施方式中，任意相邻的两个无机颗粒之间的间距记为L1，任意相邻的一个无机颗粒和一个有机颗粒之间的间距记为L2，则L1＜L2。
根据一些实施例，有机颗粒的粒径和数均粒径可以采用本领域已知的设备和方法进行测试。例如，使用扫描电子显微镜(例如ZEISS Sigma 300)，参考JY/T010-1996，获取隔离膜的扫描电子显微镜(SEM)图片。作为示例，可以按照如下方法测试：在隔离膜上任意选取一个长×宽＝50mm×100mm的测试样品，在测试样品中随机选取多个测试区域(例如5个)，并在一定放大倍率(例如测量第一种有机颗粒时为500倍，测量第二种有机颗粒时为1000倍)下，读取各测试区域中各有机颗粒的粒径(即：取有机颗粒上最远的两点间的距离作为该有机颗粒的粒径)，统计各测试区域中的有机颗粒的数量和粒径数值，取各测试区域中有机颗粒粒径的算术平均值，即为该测试样品中有机颗粒的数均粒径。为了确保测试结果的准确性，可以取多个测试样品(例如10个)重复进行上述测试，取各个测试样品的平均值作为最终的测试结果。
根据一些实施例，有机颗粒的形貌(例如：一次颗粒形貌或二次颗粒形貌)可以采用本领域已知的设备和方法进行测试。例如，可以通过使用扫描电子显微镜(例如ZEISS Sigma 300)进行测试。作为示例，可以按照如下步骤操作：首先将隔离膜裁成一定尺寸的待测样品(例如6mm×6mm)，用两片导电导热的薄片(如铜箔)将待测样品夹住，将待测样品与薄片之间用胶(如双面胶)粘住固定，用一定质量(如400g左右)平整铁块压一定时间(如1h)，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，打开氩离子截面抛光仪(例如IB-19500CP)电源并抽真空(例如10Pa-4Pa)，设置氩气流量(例如0.15MPa)和电压(例如8KV)以及抛光时间(例如2小时)，调整样品台为摇摆模式开始抛光，抛光结束后，使用扫描电子显微镜(例如ZEISS Sigma 300)得到待测样品的离子抛光断面形貌(CP)图片。
图2是本申请实施例的隔离膜在3000倍放大倍率下的离子抛光断面形貌(CP)图片。由图2可以看出，隔离膜的涂层中包括第一种有机颗粒和第二种有机颗粒；第一种有机颗粒是由多个一次颗粒组成的二次颗粒，且为不规则的非实心球体截面；第二种有机颗粒是非团聚体的一次颗粒，且为实心球体截面。
根据一些实施例，有机颗粒的物质种类可以采用本领域已知的设备和方法进行测 试。例如，可以测试材料的红外光谱，确定其包含的特征峰，从而确定物质种类。具体地，可以用本领域公知的仪器及方法对有机颗粒进行红外光谱分析，例如红外光谱仪，如采用美国尼高力(Nicolet)公司的IS10型傅里叶变换红外光谱仪，依据GB/T6040-2002红外光谱分析方法通则测试。
根据一些实施例，无机颗粒的体积平均粒径Dv50为本领域公知的含义，可采用本领域已知的仪器及方法进行测定。例如可以参照GB/T 19077-2016粒度分布激光衍射法，采用激光粒度分析仪(例如Master Size 3000)测定。
根据一些实施例，任意相邻的两个无机颗粒之间的间距是指：在隔离膜的SEM图像中，在涂层中任取相邻的两个无机颗粒(当无机颗粒为不规则形状时，可以对该颗粒做外接圆处理)，测试两个无机颗粒的圆心间距作为两个无机颗粒之间的间距，并记为L1。
根据一些实施例，任意相邻的一个无机颗粒和一个有机颗粒之间的间距是指：在隔离膜的SEM图像中，在涂层中任取相邻的一个无机颗粒和一个有机颗粒(当无机颗粒或有机颗粒为不规则形状时，可以对该颗粒做外接圆处理)，测试该无机颗粒和该有机颗粒的圆心间距作为无机颗粒和有机颗粒之间的间距，记为L2。上述有机颗粒可以取第一种有机颗粒，也可以取第二种有机颗粒。
上述间距可采用本领域已知的仪器进行测定。例如可以采用扫描电子显微镜测定。作为示例，任意相邻的一个无机颗粒和一个有机颗粒之间的间距L2可以按如下方法测试：将隔离膜制成长×宽＝50mm×100mm的测试样品；使用扫描电子显微镜(例如ZEISS Sigma300)对隔离膜进行测试。测试可参考JY/T010-1996。在测试样品中随机选取区域进行扫描测试，并在一定放大倍率(例如3000倍)下获取隔离膜的SEM图像，在SEM图像中任选相邻的一个无机颗粒和一个有机颗粒(当无机颗粒或有机颗粒为不规则体时，可以对该颗粒做外接圆处理)，测量无机颗粒(或其外接圆)的圆心与有机颗粒(或其外接圆)的圆心之间的距离，即为本申请所述的相邻的无机颗粒和有机颗粒的间距，记为L2。为了确保测试结果的准确性，可以在测试样品中取多组相邻颗粒(例如10组)重复进行上述测试，取各组测试结果的平均值作为最终的结果。
同理，也可以按照上述方法测试任意相邻的两个无机颗粒之间的间距L1。
图3是本申请实施例的隔离膜在3000倍放大倍率下的扫描电子显微镜(SEM)图片。从图3可以看出，隔离膜的涂层中包括无机颗粒、第一种有机颗粒和第二种有机颗粒，第一种有机颗粒为二次颗粒，第二种有机颗粒为一次颗粒，且第一种有机颗粒和第 二种有机颗粒嵌于无机颗粒中且在涂层表面形成凸起。按照上述记载的方法进行测量后，可得出L1＜L2。
根据一些实施例，隔离膜的透气度、横向拉伸强度(MD)、纵向拉伸强度(TD)、横向断裂伸长率、纵向断裂伸长率均具有本领域公知的含义，可以采用本领域已知的方法进行测量。例如，均可参照标准GB/T 36363-2018进行测试。
本申请还提供一种隔离膜的制备方法，包括如下步骤：
(1)提供基材；
(2)提供涂层浆料，所述涂层浆料包括组分材料和溶剂，所述组分材料包括无机颗粒和有机颗粒，所述有机颗粒包括第一种有机颗粒和第二种有机颗粒；
(3)将步骤(2)所述的涂层浆料涂布在步骤(1)所述的基材的至少一侧，形成涂层并干燥，得到所述隔离膜；
其中，所述隔离膜包括基材和设置在所述基材至少一个表面上的涂层；所述涂层包括无机颗粒、第一种有机颗粒和第二种有机颗粒；所述第一种有机颗粒和所述第二种有机颗粒嵌于所述无机颗粒中且在所述涂层表面形成凸起；所述第一种有机颗粒的数均粒径＞10μm，且所述第二种有机颗粒的数均粒径为2μm-10μm。
如图4-1所示，隔离膜包括基材(A)和涂层(B)，所述涂层(B)设置在所述基材(A)的仅一个表面上。
如图4-2所示，隔离膜包括基材(A)和涂层(B)，所述涂层(B)同时设置在所述基材(A)的两个表面上。
在本申请实施例中，对所述基材的材质没有特别的限制，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基材，例如玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏二氟乙烯中的一种或几种。所述基材可以是单层薄膜，也可以是多层复合薄膜。当所述基材为多层复合薄膜时，各层的材料可以相同，也可以不同。
在一些实施方式中，在步骤(2)中，所述溶剂可以为水，例如去离子水。
在一些实施方式中，在步骤(2)中，所述组分材料还可以包括其他有机化合物，例如，还可以包括改善耐热性的聚合物、分散剂、润湿剂、其他种类的粘结剂。其中，其他有机化合物在干燥后的涂层中均为非颗粒状。
在一些实施方式中，在步骤(2)中，在溶剂中加入组分材料并搅拌均匀得到涂层 浆料。
在一些实施方式中，在步骤(2)中，所述第一种有机颗粒的加入质量占所述组分材料的干重总和的12％以上；例如12％-30％，15％-30％，15％-25％，15％-20％，16％-22％。
在一些实施方式中，在步骤(2)中，所述第二种有机颗粒的加入质量占所述组分材料的干重总和的10％以下，例如2％-10％，3％-7％，3％-5％。
适当含量的有机颗粒可以减少隔离膜在电池制备过程中与电池卷绕工具(例如卷针)或叠片工具之间产生的静电，有效降低正负极发生短路的概率，从而提升电池的制造优率。
需要说明的是，当组分材料为固态时，组分材料的干重为该组分材料的加入质量。当组分材料为悬浮液、乳液或溶液时，组分材料的干重为该组分材料的加入质量与该组分材料的固含量的乘积。所述组分材料的干重总和即为各组分材料的干重的加和。
在一些实施方式中，在步骤(2)中，涂层浆料的固含量可以控制在28％-45％，例如，可以为30％-38％，基于重量计。当涂层浆料的固含量在上述范围内时，可以有效减少涂层的膜面问题以及降低涂布不均匀出现的概率，从而进一步改善电池的循环性能和安全性能。
在一些实施方式中，在步骤(3)中，所述涂布采用涂布机进行实施。
在本申请实施例中，对涂布机的型号没有特殊限制，可以采用市购的涂布机。
在一些实施方式中，在步骤(3)中，所述涂布可以采用转移涂布、旋转喷涂、浸涂等工艺；例如所述涂布采用转移涂布。
在一些实施方式中，所述涂布机包括凹版辊；所述凹版辊用于将涂层浆料转移到基材上。
在一些实施方式中，所述凹版辊的线数可以为100LPI-300LPI，例如，125LPI-190LPI(LPI为线/英寸)。当凹版辊的线数在上述范围内时，有助于控制第一种有机颗粒和第二种有机颗粒的数量，从而进一步改善隔离膜的循环性能和安全性能。
在一些实施方式中，在步骤(3)中，所述涂布的速度可以控制在30m/min-90m/min，例如50m/min-70m/min。当涂布的速度在上述范围内时，可以有效减少涂层的膜面问题，降低涂布不均匀的概率，从而进一步改善电池的循环性能和安全性能。
在一些实施方式中，在步骤(3)中，所述涂布的线速比可以控制在0.8-2.5，例如可以为0.8-1.5，1.0-1.5。
在一些实施方式中，在步骤(3)中，所述干燥的温度可以为40℃-70℃，例如可以为50℃-60℃。
在一些实施方式中，在步骤(3)中，所述干燥的时间可以为10s-120s，例如可以为20s-80s，20s-40s。
将上述各工艺参数控制在所给范围内，可以进一步改善本申请的隔离膜的使用性能。本领域的技术人员可以根据实际生产情况，选择性地调控上述一个或几个工艺参数。
为了进一步改善二次电池的性能，所述无机颗粒和所述有机颗粒还可选地满足前述的各参数条件中的一个或几个。此处不再赘述。
上述基材、第一种有机颗粒和第二种有机颗粒均可以通过市购获得。
本申请的隔离膜制备方法，通过一次涂布制得涂层，大大简化了隔离膜的生产工艺流程；同时，将上述方法制备的隔离膜用到电池中，可以有效改善电池的循环性能和安全性能。
[正极极片]
在二次电池中，所述正极极片通常包括正极集流体及设置在正极集流体上的正极膜层，所述正极膜层包括正极活性材料。
所述正极集流体可以采用常规金属箔片或复合集流体(可以将金属材料设置在高分子基材上形成复合集流体)。作为示例，正极集流体可以采用铝箔。
所述正极活性材料的具体种类不做限制，可以采用本领域已知的能够用于二次电池正极的活性材料，本领域技术人员可以根据实际需求进行选择。
作为示例，所述正极活性材料可以包括，但不限于，锂过渡金属氧化物，橄榄石结构的含锂磷酸盐及其各自的改性化合物中的一种或几种。锂过渡金属氧化物的示例可包括但不限于锂钴氧化物、锂镍氧化物、锂锰氧化物、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、锂镍钴铝氧化物及其改性化合物中的一种或几种。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、磷酸铁锂与碳的复合材料、磷酸锰锂、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料及其改性化合物中的一种或几种。这些材料均可以通过商业途径获得。
在一些实施方式中，上述各材料的改性化合物可以是对材料进行掺杂改性和/或表面包覆改性。
所述正极膜层通常还可选地包括粘结剂、导电剂和其他可选助剂。
作为示例，导电剂可以为超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、Super P(SP)、石墨烯及碳纳米纤维中一种或几种。
作为示例，粘结剂可以为丁苯橡胶(SBR)、水性丙烯酸树脂(water-based acrylic resin)、聚偏二氟乙烯(PVDF)、聚四氟乙烯(PTFE)、乙烯-醋酸乙烯酯共聚物(EVA)、聚丙烯酸(PAA)、羧甲基纤维素(CMC)、聚乙烯醇(PVA)及聚乙烯醇缩丁醛(PVB)中的一种或几种。
[负极极片]
在二次电池中，所述负极极片通常包括负极集流体及设置在负极集流体上的负极膜层，所述负极膜层包括负极活性材料。
所述负极集流体可以采用常规金属箔片或复合集流体(例如可以将金属材料设置在高分子基材上形成复合集流体)。作为示例，负极集流体可以采用铜箔。
所述负极活性材料的具体种类不做限制，可以采用本领域已知的能够用于二次电池负极的活性材料，本领域技术人员可以根据实际需求进行选择。作为示例，所述负极活性材料可以包括，但不限于，人造石墨、天然石墨、硬碳、软碳、硅基材料和锡基材料中的一种或几种。所述硅基材料可选自单质硅、硅氧化合物(例如氧化亚硅)、硅碳复合物、硅氮复合物、硅合金中的一种或几种。所述锡基材料可选自单质锡、锡氧化合物、锡合金中的一种或几种。这些材料均可以通过商业途径获得。
在一些实施方式中，为了进一步提高电池的能量密度，所述负极活性材料可以包括硅基材料。
所述负极膜层通常还可选地包括粘结剂、导电剂和其他可选助剂。
作为示例，导电剂可以为超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中一种或几种。
作为示例，粘结剂可以为丁苯橡胶(SBR)、水性丙烯酸树脂(water-based acrylic resin)、聚偏二氟乙烯(PVDF)、聚四氟乙烯(PTFE)、乙烯-醋酸乙烯酯共聚物(EVA)、聚乙烯醇(PVA)及聚乙烯醇缩丁醛(PVB)中的一种或几种。
作为示例，其他可选助剂可以是增稠及分散剂(例如羧甲基纤维素钠CMC-Na)、PTC热敏电阻材料等。
[电解液]
二次电池可以包括电解液，电解液在正极和负极之间起到传导离子的作用。所述电解液可以包括电解质盐和溶剂。
作为示例，电解质盐可选自六氟磷酸锂(LiPF6)、四氟硼酸锂(LiBF4)、高氯酸锂(LiClO4)、六氟砷酸锂(LiAsF6)、双氟磺酰亚胺锂(LiFSI)、双三氟甲磺酰亚胺锂(LiTFSI)、三氟甲磺酸锂(LiTFS)、二氟草酸硼酸锂(LiDFOB)、二草酸硼酸锂(LiBOB)、二氟磷酸锂(LiPO2F2)、二氟二草酸磷酸锂(LiDFOP)及四氟草酸磷酸锂(LiTFOP)中的一种或几种。
作为示例，所述溶剂可选自碳酸亚乙酯(EC)、碳酸亚丙酯(PC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)、碳酸二甲酯(DMC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸亚丁酯(BC)、氟代碳酸亚乙酯(FEC)、甲酸甲酯(MF)、乙酸甲酯(MA)、乙酸乙酯(EA)、乙酸丙酯(PA)、丙酸甲酯(MP)、丙酸乙酯(EP)、丙酸丙酯(PP)、丁酸甲酯(MB)、丁酸乙酯(EB)、1,4-丁内酯(GBL)、环丁砜(SF)、二甲砜(MSM)、甲乙砜(EMS)及二乙砜(ESE)中的一种或几种。
在一些实施方式中，电解液中还包括添加剂。例如添加剂可以包括负极成膜添加剂，也可以包括正极成膜添加剂，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、改善电池高温性能的添加剂、改善电池低温性能的添加剂等。
在一些实施方式中，二次电池可以为锂离子二次电池。
本申请实施例对二次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。如图5是作为一个示例的方形结构的二次电池5。
在一些实施例中，二次电池可包括外包装。该外包装用于封装正极极片、负极极片和电解质。
在一些实施例中，参照图6，外包装可包括壳体51和盖板53。其中，壳体51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51具有与容纳腔连通的开口，盖板53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52。电极组件52封装于所述容纳腔。电解质可采用电解液，电解液浸润于电极组件52中。二次电池5所含电极组件52的数量可以为一个或几个，可根据需求来调节。
在一些实施例中，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，如可包括聚丙烯(PP)、聚对苯二甲酸丁二醇酯(PBT)、聚丁二酸丁二醇酯(PBS)等中的一种或几种。
在一些实施例中，二次电池可以组装成电池模块，电池模块所含二次电池的数量可以为多个，具体数量可根据电池模块的应用和容量来调节。
图7是作为一个示例的电池模块4。参照图7，在电池模块4中，多个二次电池5可以是沿电池模块4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二次电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的外壳，多个二次电池5容纳于该容纳空间。
在一些实施例中，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根据电池包的应用和容量进行调节。
图8和图9是作为一个示例的电池包1。参照图8和图9，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
装置
本申请还提供一种装置，所述装置包括所述的二次电池、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作为所述装置的电源，也可以作为所述装置的能量存储单元。所述装置可以但不限于是移动设备(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。
所述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10是作为一个示例的装置。该装置为纯电动车、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，可以采用二次电池作为电源。
以下结合实施例进一步说明本申请的有益效果。
实施例
为了使本申请所解决的技术问题、技术方案及有益效果更加清楚，以下将结合实施例和附图对本申请进行进一步详细说明。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。以下对至少一个示例性实施例的描述实际上仅仅是说明性的，决不作为对本申请及其应用的任何限制。基于本申请中的实施例，本领域普通技术人员在没有付出创造性劳动前提下所获得的所有其他实施例都属于本申请保护的范围。
一、隔离膜的制备
隔离膜1：
(1)提供PE基材，例如，基材的厚度为7μm，孔隙率为40％；
(2)配制涂层浆料：将无机颗粒三氧化二铝(Al 2O 3)、第一种有机颗粒偏二氟乙烯-六氟丙烯共聚物(数均分子量为55万)、第二种有机颗粒苯乙烯-醋酸乙烯酯-吡咯烷酮共聚物(数均分子量为8万)、分散剂羧甲基纤维素钠(CMC-Na)、润湿剂有机硅改性聚醚按照干重比70：20：8：1：1在适量的溶剂去离子水中混合均匀，得到固含量为38％(按重量计)的涂层浆料。其中，无机颗粒三氧化二铝(Al 2O 3)的体积平均粒径Dv50为1μm，第一种有机颗粒为二次颗粒且数均粒径为15μm，第二种有机颗粒为一次颗粒且数均粒径为2μm。
(3)将步骤(2)配制的涂层浆料用涂布机涂布在PE基材的2个表面上，通过干燥、分切等工序，得到隔离膜1。其中，涂布机的凹版辊的线数为125LPI，涂布的速度为50m/min，涂布的线速比为1.15，干燥温度为50℃，干燥时间为25s；单位面积的隔离膜上的单面涂层重量为2.3g/m 2。
实施例中所用的材料均可以通过商购获得。例如：
基材可以购于上海恩捷新材料有限公司。
无机颗粒可以购于壹石通材料科技股份有限公司。
第一种有机颗粒可以购于阿科玛(常熟)化学有限公司。
第二种有机颗粒可以购于四川茵地乐科技有限公司。
分散剂可以购自常熟威怡科技有限公司。
润湿剂可以购自陶氏化学公司。
隔离膜2-31与隔离膜1的制备方法相似，不同点在于：调整了第一种有机颗粒和第二种有机颗粒的物质种类、以及第一种有机颗粒和第二种有机颗粒的数均粒径，具体详见表1。
二、电池的制备
实施例1
1、正极极片的制备
将正极活性材料LiNi 0.5Co 0.2Mn 0.3O 2(NCM523)、导电剂炭黑(Super P)、粘结剂聚偏二氟乙烯(PVDF)按质量比96.2:2.7:1.1在适量的溶剂N-甲基吡咯烷酮(NMP)中混合均匀，得到正极浆料，将正极浆料涂布于正极集流体铝箔上，通过烘干、冷压、分条、裁切等工序，得到正极极片。正极面密度为0.207mg/mm 2，压实密度为3.5g/cm 3。
2、负极极片的制备
将负极活性材料人造石墨、导电剂炭黑(Super P)、粘结剂丁苯橡胶(SBR)和羧甲基纤维素钠(CMC-Na)按质量比96.4:0.7:1.8:1.1在适量的溶剂去离子水中混合均匀，得到负极浆料，将负极浆料涂布于负极集流体铜箔上，通过烘干、冷压、分条、裁切等工序，得到负极极片。负极面密度为0.126mg/mm2，压实密度为1.7g/cm 3。
3、隔离膜
隔离膜采用上述制备的隔离膜1。
4、电解液的制备
将碳酸亚乙酯(EC)和碳酸甲乙酯(EMC)按质量比30:70进行混合，得到有机溶剂，将充分干燥的电解质盐LiPF 6溶解于上述混合溶剂中，电解质盐的浓度为1.0mol/L，混合均匀后获得电解液。
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，使隔离膜处于正、负极极片之间起到隔离的作用，然后卷绕得到电极组件；将电极组件置于外包装中，将上述制备好的电解液注入到干燥后的二次电池中，经过真空封装、静置、化成、整形等工序，获得二次电池。
实施例2-25和对比例1-6的二次电池与实施例1的二次电池的制备方法相似，不 同点在于使用了不同的隔离膜，具体详见表1。
三、电池性能测试
1、25℃循环性能
在25℃下，将实施例和对比例制备得到的二次电池以1C倍率恒流充电至充电截止电压4.2V，之后恒压充电至电流≤0.05C，静置30min，再以0.33C倍率恒流放电至放电截止电压2.8V，静置30min，记录此时的电池容量C0。按照此方法对电池进行1500次循环充放电，记录1500次循环后的电池容量记为C1。
电池在25℃下的循环容量保持率＝C1/C0×100％
2、45℃循环性能
在45℃下，将实施例和对比例制备得到的二次电池以1C倍率恒流充电至充电截止电压4.2V，之后恒压充电至电流≤0.05C，静置30min，再以0.33C倍率恒流放电至放电截止电压2.8V，静置30min，记录此时的电池容量记为C0。按照此方法对电池进行1500次循环充放电，记录此时的电池容量记为C1。
电池在45℃下的循环容量保持率＝C1/C0×100％
3、热蔓延性能
25℃下，将实施例和对比例制备得到的二次电池以1C倍率恒流充电至充电截止电压4.2V，之后恒压充电至电流≤0.05C，静置10min；然后在电池表面紧贴一块金属加热板，在电池的不接触加热板的位置用夹具加紧电池，并在夹具与电池间加入3mm隔热垫，200℃恒温加热至电池发生热失控；记录电池发生热失控的时间。
表1中给出了测得的各实施例和对比例的电池性能。
Figure PCTCN2020132955-appb-000001
Figure PCTCN2020132955-appb-000002
由表1可见，通过使第一种有机颗粒和第二种有机颗粒的数均粒径在本申请限定的范围内，能够显著改善电池的循环性能和安全性能。尤其是，通过进一步优化第一种有机颗粒和第二种有机颗粒的数均粒径、数均粒径比值或物质种类，能够进一步提高电池的循环性能和安全性能。相比而言，仅使用第一种有机颗粒的对比例1、5在循环性能和安全性能方面均不如本申请实施例1-25；对比例2-4、6尽管同时使用了第一种有机颗粒和第二种有机颗粒，但第一种有机颗粒的数均粒径和第二种有机颗粒的数均粒径中至少一者不在本申请限定的范围内，其在循环性能和安全性能方面虽然略好于对比例1、5，但仍不能实现与本申请实施例1-25同等程度的改善。
发明人还采用了本申请范围内的无机颗粒、第一种有机颗粒和第二种有机颗粒的其他用量和材质、其他基材、其他涂布工艺参数和其他干燥条件进行了实验，并且获得了与实施例1-25类似的改善电池的循环性能和安全性能的效果。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到各种等效的修改或替换，这些修改或替换都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以权利要求的保护范围为准。

Claims (23)

  1. 一种隔离膜，其包括：
    基材；和
    设置在所述基材至少一个表面上的涂层；
    所述涂层包括无机颗粒和有机颗粒，所述有机颗粒包括第一种有机颗粒和第二种有机颗粒；
    所述第一种有机颗粒和所述第二种有机颗粒嵌于所述无机颗粒中且在所述涂层表面形成凸起；
    所述第一种有机颗粒的数均粒径＞10μm，且所述第二种有机颗粒的数均粒径为2μm-10μm。
  2. 根据权利要求1所述的隔离膜，其中，所述第一种有机颗粒的数均粒径为12μm-25μm；可选地，所述第一种有机颗粒的数均粒径为15μm-20μm。
  3. 根据权利要求1-2中任一项所述的隔离膜，其中，所述第二种有机颗粒的数均粒径为2μm-8μm；可选地，所述第二种有机颗粒的数均粒径为3μm-7μm。
  4. 根据权利要求1-3中任一项所述的隔离膜，其中，所述第一种有机颗粒的数均粒径与所述第二种有机颗粒的数均粒径的比值≥1.5；可选地，所述第一种有机颗粒的数均粒径与所述第二种有机颗粒的数均粒径的比值≥2.0。
  5. 根据权利要求1-4中任一项所述的隔离膜，其中，所述第一种有机颗粒为二次颗粒。
  6. 根据权利要求1-5中任一项所述的隔离膜，其中，所述第二种有机颗粒为一次颗粒。
  7. 根据权利要求1-6中任一项所述的隔离膜，其中，单位面积的隔离膜上的单面涂层重量≤3.0g/m 2；可选地，单位面积的隔离膜上的单面涂层重量为1.5g/m 2-2.5g/m 2。
  8. 根据权利要求1-7中任一项所述的隔离膜，其中，所述无机颗粒的体积平均粒径Dv50≤2.5μm；可选地，所述无机颗粒的体积平均粒径Dv50为0.5μm-2.5μm。
  9. 根据权利要求1-8中任一项所述的隔离膜，其中，所述隔离膜满足下述(1)-(3)中的至少一项：
    (1)所述无机颗粒在所述涂层中的质量百分比≤70％，可选地，所述无机颗粒在所述涂层中的质量百分比为60％-70％；
    (2)所述第一种有机颗粒在所述涂层中的质量百分比≥12％，可选地，所述第一种有机颗粒在所述涂层中的质量百分比为15％-25％；
    (3)所述第二种有机颗粒在所述涂层中的质量百分比≤10％，可选地，所述第二种有机颗粒在所述涂层中的质量百分比为2％-10％。
  10. 根据权利要求1-9中任一项所述的隔离膜，其中，所述第一种有机颗粒包括含氟烯基单体单元的均聚物或共聚物，烯烃基单体单元的均聚物或共聚物，不饱和腈类单体单元的均聚物或共聚物，环氧烷类单体单元的均聚物或共聚物，以及上述各均聚物或共聚物的改性化合物中的一种或几种；
    可选地，所述第一种有机颗粒包括聚四氟乙烯、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、不同含氟烯基单体单元的共聚物、含氟烯基单体单元与烯烃基单体单元的共聚物、含氟烯基单体单元与丙烯酸类单体单元的共聚物、含氟烯基单体单元与丙烯酸酯类单体单元的共聚物，以及上述各均聚物或共聚物的改性化合物中的一种或几种。
  11. 根据权利要求1-10中任一项所述的隔离膜，其中，所述第一种有机颗粒包括偏二氟乙烯-三氟乙烯共聚物、偏二氟乙烯-六氟丙烯共聚物、偏二氟乙烯-三氟乙烯-六氟丙烯共聚物、偏二氟乙烯-六氟丙烯-丙烯酸共聚物、偏二氟乙烯-六氟丙烯-丙烯酸酯共聚物，以及上述共聚物的改性化合物中的一种或几种。
  12. 根据权利要求1-11中任一项所述的隔离膜，其中，所述第二种有机颗粒包括丙烯酸酯类单体单元的均聚物或共聚物，丙烯酸类单体单元的均聚物或共聚物，苯乙烯类单体单元的均聚物或共聚物，聚氨酯类化合物，橡胶类化合物，以及上述各均聚物或共聚物的改性化合物中的一种或几种；
    可选地，所述第二种有机颗粒包括丙烯酸酯类单体单元与苯乙烯类单体单元的共聚物，丙烯酸类单体单元与苯乙烯类单体单元的共聚物，丙烯酸类单体单元-丙烯酸酯类单体单元-苯乙烯类单体单元的共聚物，苯乙烯类单体单元与不饱和腈类单体单元的共聚物，苯乙烯类单体单元-烯烃基单体单元-不饱和腈类单体单元的共聚物，以及上述共聚物的改性化合物中的一种或几种。
  13. 根据权利要求1-12中任一项所述的隔离膜，其中，所述第二种有机颗粒包括丙烯酸丁酯-苯乙烯共聚物、甲基丙烯酸丁酯-甲基丙烯酸异辛酯共聚物、甲基丙烯酸异辛酯-苯乙烯共聚物、甲基丙烯酸酯-甲基丙烯酸-苯乙烯共聚物、丙烯酸甲酯-甲基丙烯 酸异辛酯-苯乙烯共聚物、丙烯酸丁酯-丙烯酸异辛酯-苯乙烯共聚物、丙烯酸丁酯-甲基丙烯酸异辛酯-苯乙烯共聚物、甲基丙烯酸丁酯-丙烯酸异辛酯-苯乙烯共聚物、甲基丙烯酸丁酯-甲基丙烯酸异辛酯-苯乙烯共聚物、苯乙烯-丙烯腈共聚物、苯乙烯-丁二烯-丙烯腈共聚物、丙烯酸甲酯-苯乙烯-丙烯腈共聚物、甲基丙烯酸异辛酯-苯乙烯-丙烯腈共聚物、苯乙烯-醋酸乙烯酯共聚物，苯乙烯-醋酸乙烯酯-吡咯烷酮共聚物，以及上述共聚物的改性化合物中的一种或几种。
  14. 根据权利要求1-13中任一项所述的隔离膜，其中，所述无机颗粒包括勃姆石(γ-AlOOH)、氧化铝(Al 2O 3)、硫酸钡(BaSO 4)、氧化镁(MgO)、氢氧化镁(Mg(OH) 2)、二氧化硅(SiO 2)、二氧化锡(SnO 2)、氧化钛(TiO 2)、氧化钙(CaO)、氧化锌(ZnO)、氧化锆(ZrO 2)、氧化钇(Y 2O 3)、氧化镍(NiO)、氧化铈(CeO 2)、钛酸锆(SrTiO 3)、钛酸钡(BaTiO 3)、氟化镁(MgF 2)中的一种或几种。
  15. 根据权利要求1-14中任一项所述的隔离膜，其中，所述隔离膜满足下述(1)-(5)中的一个或几个：
    (1)所述隔离膜的透气度为100s/100mL-300s/100mL，可选地，所述隔离膜的透气度为150s/100mL-250s/100mL；
    (2)所述隔离膜的横向拉伸强度(MD)为1500kgf/cm 2-3000kgf/cm 2；可选地，所述隔离膜的横向拉伸强度为1800kgf/cm 2-2500kgf/cm 2；
    (3)所述隔离膜的纵向拉伸强度(TD)为1000kgf/cm 2-2500kgf/cm 2；可选地，所述隔离膜的纵向拉伸强度为1400kgf/cm 2-2000kgf/cm 2；
    (4)所述隔离膜的横向断裂伸长率为50％-200％；可选地，所述隔离膜的横向断裂伸长率为100％-150％；
    (5)所述隔离膜的纵向断裂伸长率为50％-200％；可选地，所述隔离膜的纵向断裂伸长率为100％-150％。
  16. 根据权利要求1-15中任一项所述的隔离膜，其中，所述无机颗粒和所述有机颗粒在所述涂层中形成不均匀的孔道结构。
  17. 根据权利要求1-16中任一项所述的隔离膜，其中，任意相邻的两个无机颗粒之间的间距记为L1，任意相邻的一个无机颗粒和一个有机颗粒之间的间距记为L2，则L1＜L2。
  18. 一种权利要求1-17中任一项所述的隔离膜的制备方法，包括如下步骤：
    (1)提供基材；
    (2)提供涂层浆料，所述涂层浆料包括组分材料和溶剂，所述组分材料包括无机颗粒和有机颗粒，所述有机颗粒包括第一种有机颗粒和第二种有机颗粒；
    (3)将步骤(2)所述的涂层浆料涂布在步骤(1)所述的基材的至少一侧，形成涂层并干燥，得到所述隔离膜；
    其中，所述隔离膜包括基材和设置在所述基材至少一个表面上的涂层；所述涂层包括无机颗粒、第一种有机颗粒和第二种有机颗粒；所述第一种有机颗粒和所述第二种有机颗粒嵌于所述无机颗粒中且在所述涂层表面形成凸起；所述第一种有机颗粒的数均粒径＞10μm，且所述第二种有机颗粒的数均粒径为2μm-10μm。
  19. 根据权利要求18所述的制备方法，其中，所述方法满足下述(1)-(8)中的一个或几个：
    (1)在所述步骤(2)中，所述第一种有机颗粒的加入质量占所述组分材料的干重总和的12％以上；可选为12％-30％；
    (2)在所述步骤(2)中，所述第二种有机颗粒的加入质量占所述组分材料的干重总和的10％以下，可选为2％-10％；
    (3)在所述步骤(2)中，所述涂层浆料的固含量为28％-45％，可选为30％-38％，基于重量计；
    (4)在所述步骤(3)中，所述涂布采用涂布机，所述涂布机包括凹版辊，所述凹版辊的线数为100LPI-300LPI，可选为125LPI-190LPI；
    (5)在所述步骤(3)中，所述涂布的速度为30m/min-90m/min，可选为50m/min-70m/min；
    (6)在所述步骤(3)中，所述涂布的线速比为0.8-2.5，可选为0.8-1.5；
    (7)在所述步骤(3)中，所述干燥的温度为40℃-70℃，可选为50℃-60℃；
    (8)在所述步骤(3)中，所述干燥的时间为10s-120s，可选为20s-80s。
  20. 一种二次电池，其包括根据权利要求1-17中任一项所述的隔离膜或根据权利要求18-19中任一项所述制备方法得到的隔离膜。
  21. 一种电池模块，包括根据权利要求20所述的二次电池。
  22. 一种电池包，包括根据权利要求21所述的电池模块。
  23. 一种装置，包括根据权利要求20所述的二次电池、根据权利要求21所述的电 池模块、或根据权利要求22所述的电池包中的至少一种。
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Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024108520A1 (zh) * 2022-11-25 2024-05-30 宁德时代新能源科技股份有限公司 二次电池和用电装置
CN115939673A (zh) * 2022-11-30 2023-04-07 宁德时代新能源科技股份有限公司 隔离膜及其制备方法、电池和用电设备
WO2024119290A1 (zh) * 2022-12-05 2024-06-13 宁德时代新能源科技股份有限公司 隔离膜及其制备方法、二次电池和用电装置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102630353A (zh) * 2009-09-30 2012-08-08 日本瑞翁株式会社 二次电池用多孔膜及二次电池
CN104659311A (zh) * 2013-11-19 2015-05-27 三星Sdi株式会社 隔板、其制造方法、包括其的锂电池和制造锂电池的方法
US20150240039A1 (en) * 2012-09-11 2015-08-27 Jsr Corporation Composition for producing protective film, protective film, and electrical storage device
CN109037555A (zh) * 2018-07-03 2018-12-18 上海恩捷新材料科技股份有限公司 锂离子电池隔离膜及其制备方法
CN111492507A (zh) * 2017-10-30 2020-08-04 阿科玛股份有限公司 锂离子电池隔膜
CN111954943A (zh) * 2018-02-26 2020-11-17 三星Sdi株式会社 隔板、用于制造其的方法和包括其的锂电池

Family Cites Families (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5225173B2 (ja) 2009-03-30 2013-07-03 三菱製紙株式会社 リチウムイオン二次電池用セパレータ
KR101515357B1 (ko) * 2012-02-29 2015-04-28 제일모직주식회사 유기 및 무기 혼합물 코팅층을 포함하는 분리막 및 이를 이용한 전지
KR101655278B1 (ko) * 2013-10-04 2016-09-07 주식회사 엘지화학 리튬 이차전지
CN103904276B (zh) * 2014-03-28 2017-09-19 东莞新能源科技有限公司 复合多孔隔离膜及电化学装置
CN105958000B (zh) 2016-07-11 2019-05-03 东莞市魔方新能源科技有限公司 一种锂离子电池复合隔膜及其制备方法
WO2018034094A1 (ja) * 2016-08-17 2018-02-22 日本ゼオン株式会社 非水系二次電池多孔膜用組成物、非水系二次電池用多孔膜及び非水系二次電池
JP6872932B2 (ja) * 2017-03-01 2021-05-19 旭化成株式会社 蓄電デバイス用セパレータ
CN107895765A (zh) * 2017-10-13 2018-04-10 深圳市旭然电子有限公司 无机/有机复合多孔性隔离膜、制备方法及其锂离子电池
CN109950451A (zh) * 2017-12-21 2019-06-28 宁德时代新能源科技股份有限公司 一种隔离膜，其制备方法及含有该隔离膜的电化学装置
KR102233770B1 (ko) * 2018-02-01 2021-03-30 삼성에스디아이 주식회사 분리막, 이를 채용한 리튬전지 및 분리막의 제조 방법
CN108565381B (zh) * 2018-04-03 2021-06-15 上海恩捷新材料科技有限公司 电池涂布膜浆料、电池隔膜、二次电池及其制备方法
WO2019242016A1 (en) * 2018-06-22 2019-12-26 Shanghai Energy New Materials Technology Co., Ltd. Separators, electrochemical devices comprising separators, and methods for making separators
US20220094019A1 (en) * 2019-01-04 2022-03-24 Ceigard, LLC Coated microporous membranes, and battery separators, batteries, vehicles, and devices comprising the same
WO2020175292A1 (ja) * 2019-02-28 2020-09-03 日本ゼオン株式会社 電気化学素子機能層用組成物、電気化学素子用機能層及び電気化学素子
CN112956072B (zh) * 2019-02-28 2023-03-14 日本瑞翁株式会社 电化学元件用功能层、带电化学元件用功能层的间隔件及电化学元件
CN109980164A (zh) * 2019-03-18 2019-07-05 宁德新能源科技有限公司 隔离膜和电化学装置
CN111244365B (zh) 2020-01-18 2020-11-10 江苏厚生新能源科技有限公司 一种孔径一致的复合涂覆隔膜及其制备方法
CN111668427A (zh) 2020-06-30 2020-09-15 沧州明珠锂电隔膜有限公司 一种耐温性和粘接性优良的复合电池隔膜及制备方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102630353A (zh) * 2009-09-30 2012-08-08 日本瑞翁株式会社 二次电池用多孔膜及二次电池
US20150240039A1 (en) * 2012-09-11 2015-08-27 Jsr Corporation Composition for producing protective film, protective film, and electrical storage device
CN104659311A (zh) * 2013-11-19 2015-05-27 三星Sdi株式会社 隔板、其制造方法、包括其的锂电池和制造锂电池的方法
CN111492507A (zh) * 2017-10-30 2020-08-04 阿科玛股份有限公司 锂离子电池隔膜
CN111954943A (zh) * 2018-02-26 2020-11-17 三星Sdi株式会社 隔板、用于制造其的方法和包括其的锂电池
CN109037555A (zh) * 2018-07-03 2018-12-18 上海恩捷新材料科技股份有限公司 锂离子电池隔离膜及其制备方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP4109658A4 *

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EP4109658A4 (en) 2023-05-31
KR102537203B1 (ko) 2023-05-26
JP7446459B2 (ja) 2024-03-08
US20230024649A1 (en) 2023-01-26
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