WO2024065161A1 - 粘结剂组合物和包含其的隔离膜 - Google Patents

粘结剂组合物和包含其的隔离膜 Download PDF

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WO2024065161A1
WO2024065161A1 PCT/CN2022/121639 CN2022121639W WO2024065161A1 WO 2024065161 A1 WO2024065161 A1 WO 2024065161A1 CN 2022121639 W CN2022121639 W CN 2022121639W WO 2024065161 A1 WO2024065161 A1 WO 2024065161A1
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monomer
acrylate
binder composition
polymer
composition according
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PCT/CN2022/121639
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English (en)
French (fr)
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李雷
康海杨
孙成栋
郑义
艾少华
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宁德时代新能源科技股份有限公司
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Priority to PCT/CN2022/121639 priority Critical patent/WO2024065161A1/zh
Priority to EP22942941.0A priority patent/EP4372049A1/en
Priority to KR1020237038040A priority patent/KR102658573B1/ko
Publication of WO2024065161A1 publication Critical patent/WO2024065161A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K7/00—Use of ingredients characterised by shape
    • C08K7/22—Expanded, porous or hollow particles
    • C08K7/24—Expanded, porous or hollow particles inorganic
    • C08K7/26—Silicon- containing compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/42—Nitriles
    • C08F220/44—Acrylonitrile
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/42—Nitriles
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    • C08F220/48—Acrylonitrile with nitrogen-containing monomers
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    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/52—Amides or imides
    • C08F220/54—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
    • C08F220/56—Acrylamide; Methacrylamide
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/12—Powdering or granulating
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/12—Powdering or granulating
    • C08J3/128—Polymer particles coated by inorganic and non-macromolecular organic compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
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    • C08K3/34—Silicon-containing compounds
    • C08K3/36—Silica
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/04—Homopolymers or copolymers of esters
    • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
    • C08L33/08—Homopolymers or copolymers of acrylic acid esters
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/04—Homopolymers or copolymers of esters
    • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
    • C08L33/10—Homopolymers or copolymers of methacrylic acid esters
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/04—Homopolymers or copolymers of esters
    • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
    • C08L33/10—Homopolymers or copolymers of methacrylic acid esters
    • C08L33/12—Homopolymers or copolymers of methyl methacrylate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/24—Homopolymers or copolymers of amides or imides
    • C08L33/26—Homopolymers or copolymers of acrylamide or methacrylamide
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • 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
    • H01M50/211—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape adapted for pouch 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
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/451—Separators, membranes or diaphragms characterised by the material having a layered structure comprising layers of only organic material and layers containing inorganic material
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K2201/00—Specific properties of additives
    • C08K2201/002—Physical properties
    • C08K2201/005—Additives being defined by their particle size in general
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K2201/00—Specific properties of additives
    • C08K2201/011—Nanostructured additives
    • 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
    • H01M2220/10—Batteries in stationary systems, e.g. emergency power source in plant
    • 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
    • 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
    • H01M2220/30—Batteries in portable systems, e.g. mobile phone, laptop
    • 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
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present application relates to the field of lithium battery technology, and in particular to a binder composition and a separator containing the same.
  • the present application also relates to a secondary battery, a battery module, a battery pack and an electrical device.
  • secondary batteries are widely used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace and other fields.
  • energy storage power systems such as hydropower, thermal power, wind power and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace and other fields.
  • binders are often used in the separator of secondary batteries.
  • the existing binders have poor viscosity and are easy to cause pore blocking in the substrate, resulting in a lower porosity of the separator, a worse flow of ions in the separator, and an increase in the resistance in the separator, which affects the cycle performance of the secondary battery.
  • the present application provides a binder composition, and a separator, a secondary battery, a battery pack and an electrical device comprising the composition.
  • the first aspect of the present application provides a binder composition, comprising a polymer and ceramic particles; the polymer comprises a structural unit derived from a first monomer, a second monomer and a third monomer, and the molar ratio of the first monomer, the second monomer and the third monomer is 50 to 58:40 to 44:2 to 6;
  • the first type of monomer is selected from one or more compounds of formula I:
  • R1 is selected from hydrogen atom and straight or branched C1-6 alkyl
  • R2 is selected from substituted or unsubstituted straight or branched C1-15 alkyl, C3-6 cycloalkyl and isobornyl, and in the case of substitution, the substituent is selected from hydroxyl and C1-6 alkyl;
  • the second monomer is selected from one or more compounds of formula II:
  • R 3 is selected from a hydrogen atom and a linear or branched C1-6 alkyl group
  • the third monomer is selected from one or more compounds of formula III:
  • R4 is selected from hydrogen atom and linear or branched C1-6 alkyl
  • R5 is selected from hydrogen atom, hydroxy C1-6 alkyl and C1-6 alkoxy.
  • the adhesive composition of the present application has good bonding effect, and can increase the porosity of the isolation membrane, improve the ion conductivity, reduce the internal resistance of the isolation membrane, and improve the cycle performance of the secondary battery.
  • R1 is selected from hydrogen atom and methyl
  • R2 is selected from substituted or unsubstituted linear or branched C1-6 alkyl, in the case of substitution, the substituent is hydroxyl
  • R3 is selected from hydrogen atom and methyl
  • R4 is selected from hydrogen atom and methyl
  • R5 is selected from hydrogen atom, hydroxy C1-4 alkyl and C1-4 alkoxy.
  • the first type of monomer is selected from one or more of methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-propyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate; and/or the second type of monomer is acrylonitrile or methacrylonitrile; and/or the third type of monomer is selected from one or more of acrylamide
  • first, second and/or third monomers respectively helps to improve the ionic conductivity of the isolation membrane and increase the cycle capacity retention rate of the battery.
  • the molar ratio of the first monomer, the second monomer and the third monomer is 50 to 57: 41 to 44: 2 to 6.
  • the molar ratio within the above range is more conducive to the binder composition further improving the ionic conductivity of the separator and improving the cycle capacity retention rate of the battery.
  • the weight ratio of the polymer to the ceramic particles is 40 to 90: 10 to 60, and optionally 50 to 80: 20 to 50.
  • the weight ratio of the polymer to the ceramic particles is within the above range, the bonding effect of the binder with the isolation membrane and the electrode piece can be ensured, and the isolation membrane can have appropriate porosity and good ionic conductivity.
  • the weight average molecular weight of the polymer is 60000 to 120000, optionally 63300 to 118800.
  • the weight average molecular weight of the polymer is within the above range, so that the binder composition of the present application can have appropriate fluidity when bonding, thereby achieving a good bonding effect, thereby improving the cycle performance of the secondary battery.
  • the average particle size Dv50 of the ceramic particles is 40 nm to 110 nm, optionally 45 nm to 106 nm, more optionally 50 nm to 100 nm, and even more optionally 56 nm to 89 nm. Further controlling the average particle size of the ceramic particles can further improve the ionic conductivity and capacity retention rate.
  • the ceramic particles are porous particles, and the average pore size of the porous particles is 0.3nm to 6.0nm, optionally 0.5nm to 5.7nm, more optionally 1.0nm to 5.0nm, and more optionally 1.3nm to 3.8nm. Selecting porous particle materials and controlling their average pore size is conducive to further improving the porosity and ionic conductivity of the separator while ensuring the thermal stability of the separator, as well as the cycle capacity retention rate of the secondary battery.
  • the ceramic particles are porous silica particles.
  • the use of porous silica particles can further increase the porosity and ion conductivity of the separator, reduce the internal resistance of the separator, and improve the cycle performance of the secondary battery.
  • the polymer is coated on the ceramic particles, which helps to ensure that the binder composition can be evenly applied to the substrate in an ideal ratio to achieve improved heat resistance, porosity and good bonding effect.
  • the second aspect of the present application provides a separator, the separator comprising a base layer and a coating layer disposed on at least one surface of the base layer, the coating layer comprising the binder composition of the first aspect of the present application.
  • the separator of the present application can be stably bonded to the pole piece, has an increased porosity, improves ion conductivity, reduces the internal resistance of the separator, and improves the cycle performance of the secondary battery.
  • a third aspect of the present application provides a secondary battery, comprising the adhesive according to the first aspect of the present application, and/or the isolation film according to the second aspect of the present application.
  • a fourth aspect of the present application provides a battery module, comprising the secondary battery of the third aspect of the present application.
  • the fifth aspect of the present application provides a battery pack, comprising the battery module of the fourth aspect of the present application.
  • the sixth aspect of the present application provides an electrical device comprising at least one selected from the secondary battery of the third aspect of the present application, the battery module of the fourth aspect of the present application, or the battery pack of the fifth aspect of the present application.
  • the adhesive of the present application has good bonding properties, and can also increase the porosity of the isolation membrane, reduce the internal resistance of the isolation membrane, and improve the cycle performance of the secondary battery.
  • FIG. 1 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • FIG. 2 is an exploded view of the secondary battery according to the embodiment of the present application shown in FIG. 1 .
  • FIG. 3 is a schematic diagram of a battery module according to an embodiment of the present application.
  • FIG. 4 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 5 is an exploded view of the battery pack shown in FIG. 4 according to an embodiment of the present application.
  • FIG. 6 is a schematic diagram of an electric device using a secondary battery as a power source according to an embodiment of the present application.
  • range disclosed in the present application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular range.
  • the range defined in this way can be inclusive or exclusive of end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60-120 and 80-110 is listed for a specific parameter, it is understood that the range of 60-110 and 80-120 is also expected.
  • the numerical range "a-b" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers.
  • the numerical range "0-5" represents that all real numbers between "0-5" have been fully listed herein, and "0-5" is just an abbreviation of these numerical combinations.
  • a parameter is expressed as an integer ⁇ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially.
  • the method may further include step (c), which means that step (c) may be added to the method in any order.
  • the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.
  • the “include” and “comprising” mentioned in this application represent open-ended or closed-ended expressions.
  • the “include” and “comprising” may represent that other components not listed may also be included or only the listed components may be included or only the listed components may be included.
  • the term "or” is inclusive.
  • the phrase “A or B” means “A, B, or both A and B”. More specifically, any of the following conditions satisfies the condition "A or B”: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).
  • secondary batteries are widely used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace and other fields.
  • energy storage power systems such as hydropower, thermal power, wind power and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace and other fields.
  • secondary batteries have made great progress, higher requirements have been put forward for their energy density, cycle performance and safety performance.
  • the separator naturally becomes one of the focuses of attention of technicians.
  • ceramic particles for example, inorganic oxide particles such as silica, alumina, boehmite, etc.
  • a binder is applied to the separator coated with ceramic particles and bonded to the pole piece to prepare a secondary battery.
  • this method has its defects. First, the ceramic particles are easy to fall into the pores of the substrate and reduce the porosity of the separator, which is not conducive to ion movement; secondly, the bonding effect of the existing binder is poor.
  • the present application proposes a binder composition, which includes a polymer that plays a bonding role and ceramic particles that improve safety performance, which reduces or even avoids the occurrence of pore blocking and achieves a good bonding effect.
  • the polymer in the binder composition of the present application also helps to improve ionic conductivity due to the selection and proportion control of its monomers.
  • the binder composition of the present application can increase the porosity of the isolation membrane, increase the ionic conductivity, and improve the cycle performance of the secondary battery.
  • the present application provides a binder composition, which includes a polymer and ceramic particles, wherein the polymer includes a structural unit derived from a first monomer, a second monomer, and a third monomer, and the molar ratio of the first monomer, the second monomer, and the third monomer is 50 to 58:40 to 44:2 to 6;
  • the first type of monomer is selected from one or more compounds of formula I:
  • R1 is selected from a hydrogen atom and a linear or branched C1-6 alkyl group
  • R2 is selected from a substituted or unsubstituted linear or branched C1-15 alkyl group, a C3-6 cycloalkyl group and an isobornyl group, and in the case of substitution, the substituent is selected from a hydroxyl group and a C1-6 chain alkyl group;
  • the second monomer is selected from one or more compounds of formula II:
  • R 3 is selected from a hydrogen atom and a linear or branched C1-6 alkyl group
  • the third monomer is selected from one or more compounds of formula III:
  • R 4 is selected from a hydrogen atom and a linear or branched C1-6 alkyl group
  • R 5 is selected from a hydrogen atom, a hydroxy C1-6 alkyl group and a C1-6 alkoxy group.
  • the adhesive composition of the present application has good bonding effect, and can increase the porosity of the isolation membrane, improve the ion conductivity, reduce the internal resistance of the isolation membrane, and enhance the cycle performance of the secondary battery.
  • the first type of monomer is an acrylate monomer, which can improve the anti-swelling ability of the binder, and as a flexible monomer segment in the molecular segment, it can adjust the glass transition temperature of the polymer, thereby helping the binder composition to play a good bonding effect.
  • the second type of monomer is an acrylonitrile monomer, which has a strong polar cyano group and helps to improve ionic conductivity.
  • the third type of monomer is an acrylamide monomer, in which the amide group mainly plays a cross-linking role and helps to adjust the molecular weight of the polymer.
  • the molar ratio of the above three types of monomers should be controlled within a certain range so that the polymer has an ideal molecular weight and glass transition temperature, thereby helping to improve ionic conductivity while ensuring the bonding performance of the binder.
  • R1 is selected from hydrogen atom and methyl
  • R2 is selected from substituted or unsubstituted straight or branched C1-6 alkyl, in the case of substitution, the substituent is hydroxyl
  • R3 is selected from hydrogen atom and methyl
  • R4 is selected from hydrogen atom and methyl
  • R5 is selected from hydrogen atom, hydroxy C1-4 alkyl and C1-4 alkoxy.
  • the first monomer is selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-propyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, and one or more of 2-hydroxypropyl methacrylate.
  • the second monomer is acrylonitrile or methacrylonitrile.
  • the third monomer is selected from one or more of acrylamide,
  • first, second and/or third monomers respectively helps to improve the ionic conductivity of the isolation membrane and increase the cycle capacity retention rate of the battery.
  • the molar ratio of the first monomer, the second monomer, and the third monomer is 50 to 57: 41 to 44: 2 to 6.
  • the molar ratio within the above range is more helpful for the binder composition to further improve the ionic conductivity of the separator and improve the cycle capacity retention rate of the battery.
  • the molar percentage of the first monomer is 50-58mol%, optionally 50-57mol%; alternatively, the molar percentage of the first monomer is 50mol%, 51mol%, 52mol%, 53mol%, 54mol%, 55mol%, 56mol%, 57mol% or 58mol%, or in the range of any two of the above values.
  • the molar percentage of the second monomer is 40-44mol%, optionally 41-44mol%; alternatively, the molar percentage of the second monomer is 40mol%, 41mol%, 42mol%, 43mol% or 44mol%, or in the range of any two of the above values.
  • the molar percentage of the third monomer is 2-6 mol%; optionally, the molar percentage of the third monomer is 2 mol%, 3 mol%, 4 mol%, 5 mol% or 6 mol%, or within the range of any two of the above values.
  • the weight ratio of the polymer to the ceramic particles is 40 to 90: 10 to 60, and optionally 50 to 80: 20 to 50.
  • the weight ratio of the polymer to the ceramic particles is within the above range, the bonding effect of the binder with the isolation membrane and the electrode can be further ensured, and the isolation membrane can have appropriate porosity and good ionic conductivity.
  • the weight average molecular weight of the polymer is 60,000 to 120,000, optionally 63,300 to 118,800.
  • the weight average molecular weight of the polymer is within the above range, so that the binder composition of the present application can have appropriate fluidity during bonding, thereby achieving a good bonding effect, thereby improving the cycle performance of the secondary battery.
  • the average particle size Dv50 of the ceramic particles is 40nm to 110nm, optionally 45nm to 106nm; alternatively, the average particle size Dv50 of the ceramic particles is 40nm, 45nm, 50nm, 56nm, 70nm, 89nm, 100nm, 106nm or 110nm, or within the range of any two of these values.
  • the average particle size Dv50 of the ceramic particles is 50nm to 100nm, more optionally 56nm to 89nm. Further controlling the average particle size of the ceramic particles can further improve the ionic conductivity and capacity retention rate.
  • the material of the ceramic particles can be any suitable conventional material in the art.
  • the ceramic particles are selected from alumina, boehmite, titanium dioxide and silicon dioxide.
  • the ceramic particles may be porous particles or solid particles (ie, non-porous particles). In some embodiments, the ceramic particles are porous particles.
  • the average pore size of the porous particles is 0.3nm to 6.0nm; alternatively, the average pore size is 0.5nm, 1nm, 1.3nm, 3nm, 3.8nm, 5nm or 5.7nm, or within a range consisting of any two of these values.
  • the average pore size is 0.5nm to 5.7nm, more optionally 1.0nm to 5.0nm, and more optionally 1.3nm to 3.8nm. Further selecting a porous particle material, and preferably controlling its average pore size, is conducive to further improving the porosity and ionic conductivity of the isolation membrane while ensuring the thermal stability of the isolation membrane, as well as the cycle capacity retention rate of the secondary battery.
  • the ceramic particles are porous silica particles.
  • the porous silica particles can further improve the porosity and ion conductivity of the separator, reduce the internal resistance of the separator, and improve the cycle performance of the secondary battery.
  • the polymer is coated on the ceramic particles. Before application, the polymer is coated on the ceramic particles to reduce or avoid the particles falling into the pores of the isolation membrane to cause pore blockage, while ensuring that the polymer and ceramic particles can be evenly applied to the substrate in an ideal ratio to achieve improved heat resistance, porosity and good bonding effect. In some embodiments, the polymer is coated on the porous silica particles.
  • the present application provides an isolation film, which includes a base layer and a coating layer disposed on at least one surface of the base layer, wherein the coating layer contains the adhesive of the present application.
  • the present application has no particular restriction on the type of material of the isolation membrane base layer, and any known porous structure base layer with good chemical stability and mechanical stability can be selected.
  • the material of the base layer of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the isolation membrane can be a single-layer film or a multi-layer composite film, without particular limitation. When the isolation membrane is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.
  • a third aspect of the present application provides a secondary battery, comprising the binder of the present application and/or the isolation film of the present application.
  • a fourth aspect of the present application provides a battery module, comprising the secondary battery of the third aspect.
  • a fifth aspect of the present application provides a battery pack, comprising the battery module of the fourth aspect.
  • a sixth aspect of the present application provides an electrical device comprising at least one selected from the secondary battery of the third aspect, the battery module of the fourth aspect, and the battery pack of the fifth aspect.
  • a secondary battery is provided.
  • the secondary battery is a lithium ion secondary battery.
  • a secondary battery includes a positive electrode sheet, a negative electrode sheet, an electrolyte and a separator.
  • active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet.
  • the electrolyte plays the role of conducting ions between the positive electrode sheet and the negative electrode sheet.
  • the separator is set between the positive electrode sheet and the negative electrode sheet, mainly to prevent the positive and negative electrodes from short-circuiting, while allowing ions to pass through.
  • the positive electrode plate includes a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, wherein the positive electrode film layer includes the positive electrode active material of the first aspect of the present application.
  • the positive electrode current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.
  • the positive electrode current collector may be a metal foil or a composite current collector.
  • aluminum foil may be used as the metal foil.
  • the composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base.
  • the composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene terephthalate
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the positive electrode active material may be a positive electrode active material for a battery known in the art.
  • the positive electrode active material may include at least one of the following materials: lithium-containing phosphates with an olivine structure, lithium transition metal oxides and their respective modified compounds, sodium transition metal oxides, polyanionic compounds, and Prussian blue compounds.
  • the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more.
  • lithium transition metal oxides may include, but are not limited to , lithium cobalt oxide (such as LiCoO2 ), lithium nickel oxide (such as LiNiO2 ), lithium manganese oxide (such as LiMnO2 , LiMn2O4 ), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi1 / 3Co1 / 3Mn1 / 3O2 (also referred to as NCM333 ), LiNi0.5Co0.2Mn0.3O2 (also referred to as NCM523 ) , LiNi0.5Co0.25Mn0.25O2 (also referred to as NCM211 ) , LiNi0.6Co0.2Mn0.2O2 (also referred to as NCM622 ), LiNi0.8Co0.1Mn0.1O2 (also referred to as NCM811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05
  • lithium-containing phosphates with an olivine structure may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO 4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 (also referred to as LFP)
  • LiMnPO 4 lithium manganese phosphate
  • LiMnPO 4 lithium manganese phosphate
  • LiMnPO 4 lithium manganese phosphate and carbon
  • the transition metal in the sodium transition metal oxide, may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce.
  • the sodium transition metal oxide is, for example, Na x M y O 2 , wherein M is one or more of Ti, V, Mn, Co, Ni, Fe, Cr and Cu, 0 ⁇ x ⁇ 1, 0.5 ⁇ y ⁇ 1.5.
  • the positive electrode active material may be Na 0.88 Cu 0.24 Fe 0.29 Mn 0.47 O 2 .
  • the polyanionic compound may be a compound having sodium ions, transition metal ions and tetrahedral (YO 4 ) n- anion units.
  • the transition metal may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce;
  • Y may be at least one of P, S and Si; and
  • n represents the valence state of (YO 4 ) n- .
  • the polyanionic compound may also be a compound having sodium ions, transition metal ions, tetrahedral (YO 4 ) n- anion units and halogen anions.
  • the transition metal may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce;
  • Y may be at least one of P, S and Si, and n represents the valence state of (YO 4 ) n- ;
  • the halogen may be at least one of F, Cl and Br.
  • the polyanionic compound may also be a compound having sodium ions, tetrahedral (YO 4 ) n- anion units, polyhedral units (ZO y ) m+ and optional halogen anions.
  • Y may be at least one of P, S and Si
  • n represents the valence state of (YO 4 ) n-
  • Z represents a transition metal, which may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce
  • m represents the valence state of (ZO y ) m+
  • the halogen may be at least one of F, Cl and Br.
  • the polyanionic compound is at least one of NaFePO 4 , Na 3 V 2 (PO 4 ) 3 , NaM′PO 4 F (M′ is one or more of V, Fe, Mn and Ni), and Na 3 (VO y ) 2 (PO 4 ) 2 F 3-2y (0 ⁇ y ⁇ 1).
  • the Prussian blue compound may be a compound having sodium ions, transition metal ions and cyanide ions (CN - ).
  • the transition metal may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce.
  • the Prussian blue compound is, for example, Na a Me b Me' c (CN) 6 , wherein Me and Me' are each independently at least one of Ni, Cu, Fe, Mn, Co and Zn, 0 ⁇ a ⁇ 2, 0 ⁇ b ⁇ 1, 0 ⁇ c ⁇ 1.
  • the positive electrode film layer may also optionally include a binder.
  • the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin.
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • PTFE polytetrafluoroethylene
  • vinylidene fluoride-tetrafluoroethylene-propylene terpolymer vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer
  • the positive electrode film layer may further include a conductive agent, which may include, for example, at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • a conductive agent which may include, for example, at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • the positive electrode sheet can be prepared in the following manner: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.
  • a solvent such as N-methylpyrrolidone
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode film layer includes a negative electrode active material.
  • the negative electrode current collector has two surfaces opposite to each other in its thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • a metal foil a copper foil may be used.
  • the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material substrate.
  • the composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene terephthalate
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative electrode active material may adopt the negative electrode active material for the battery known in the art.
  • the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.
  • the tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys.
  • the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.
  • the negative electrode film layer may further include a binder.
  • the binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the negative electrode film layer may further include a conductive agent, which may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • a conductive agent which may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the negative electrode film layer may optionally include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).
  • a thickener eg, sodium carboxymethyl cellulose (CMC-Na)
  • the negative electrode sheet can be prepared in the following manner: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.
  • a solvent such as deionized water
  • the electrolyte plays the role of conducting ions between the positive electrode and the negative electrode.
  • the present application has no specific restrictions on the type of electrolyte, which can be selected according to needs.
  • the electrolyte can be liquid, gel or all-solid.
  • the electrolyte is an electrolyte solution, which includes an electrolyte salt and a solvent.
  • the electrolyte salt may be selected from one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate and lithium tetrafluorooxalate phosphate, sodium hexafluorophosphate (NaPF 6 ), sodium hexafluoroborate (NaBF 4 ), NaN(SO 2 F) 2 (abbreviated as NaFSI), NaClO 4 , NaAsF 6 , NaB(C 2 O 4 ) 2 (abbreviated as NaBOB), NaBF 2 (C 2 O 4 )
  • the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane sulfone, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • the electrolyte may further include additives, such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.
  • additives such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.
  • the positive electrode sheet, the negative electrode sheet, and the separator may be formed into an electrode assembly by a winding process or a lamination process.
  • the secondary battery may include an outer package for packaging the positive electrode sheet, the negative electrode sheet and the electrolyte.
  • the positive electrode sheet, the negative electrode sheet and the separator may be laminated or wound to form a laminated structure battery cell or a wound structure battery cell, and the battery cell is packaged in the outer package; the electrolyte adopts the electrolyte described in the first aspect of the present application, and the electrolyte is infiltrated in the battery cell.
  • the number of batteries in the secondary battery may be one or more, which can be adjusted according to demand.
  • the present application provides an electrode assembly.
  • the positive electrode sheet, the negative electrode sheet and the separator can be made into an electrode assembly by a winding process or a lamination process.
  • the outer packaging can be used to encapsulate the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the secondary battery may be a soft package, such as a bag-type soft package.
  • the material of the soft package may be plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), etc.
  • the outer packaging of the secondary battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.
  • FIG1 is a secondary battery 5 of a square structure as an example.
  • the outer package may include a shell 51 and a cover plate 53.
  • the shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity.
  • the shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity.
  • the positive electrode sheet, the negative electrode sheet and the isolation film can form an electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is encapsulated in the receiving cavity.
  • the electrolyte is infiltrated in the electrode assembly 52.
  • the number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.
  • secondary batteries may be assembled into a battery module.
  • the number of secondary batteries contained in the battery module may be one or more, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery module.
  • FIG3 is a battery module 4 as an example.
  • a plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4. Of course, they may also be arranged in any other manner. Further, the plurality of secondary batteries 5 may be fixed by fasteners.
  • the battery module 4 may further include a housing having a housing space, and the plurality of secondary batteries 5 are housed in the housing space.
  • the battery modules described above may also be assembled into a battery pack.
  • the battery pack may contain one or more battery modules, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery pack.
  • FIG4 and FIG5 are battery packs 1 as an example.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box.
  • the battery box includes an upper box body 2 and a lower box body 3, and the upper box body 2 can be covered on the lower box body 3 to form a closed space for accommodating the battery modules 4.
  • the plurality of battery modules 4 can be arranged in the battery box in any manner.
  • the present application also provides an electrical device, which includes at least one of the secondary battery, battery module, or battery pack provided in the present application.
  • the secondary battery, battery module, or battery pack can be used as a power source for the electrical device, and can also be used as an energy storage unit for the electrical device.
  • the electrical device may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited to these.
  • a secondary battery, a battery module or a battery pack may be selected according to its usage requirements.
  • Fig. 6 is an example of an electric device.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.
  • a battery pack or a battery module may be used.
  • a device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is usually required to be thin and light, and a secondary battery may be used as a power source.
  • Preparation Examples 2 to 5 are the same as those of Preparation Example 1, except that the molar ratios of the three monomers are 51:43:6, 52:42:6, 53:41:6 and 54:40:6, respectively, and the total mass of the three monomers is 100 g, to prepare polymers 2 to 5.
  • the molar ratios of the three monomers are 54:43:3, 55:42:3, 56:41:3, and 57:40:3, respectively, and the total mass of the three monomers is 100 g.
  • the remaining preparation steps are the same as those in Preparation Example 1 to obtain polymers 17 to 20.
  • the molar ratios of the three monomers are 55:43:2, 56:42:2, 57:41:2, and 58:40:2, respectively, and the total mass of the three monomers is 100 g.
  • the remaining preparation steps are the same as those in Preparation Example 1 to obtain polymers 22 to 25.
  • the weight average molecular weight of polymer 1-27 and comparative polymer 1-2 obtained in the above preparation examples and comparative preparation examples was determined by using a Waters 1515 gel permeation chromatograph; wherein the mobile phase was N,N-dimethylformamide, the standard sample was a linear polymethyl methacrylate polymer with a narrow molecular weight distribution, and the solvent flow rate was 1.0 ml/min.
  • Table 1 shows the monomers and their molar ratios in the above Preparation Examples 1-27 and Comparative Preparation Examples 1-2, as well as the weight average molecular weight of the finally obtained polymers.
  • the ceramic particles in the following examples are all commercially available.
  • the average particle size Dv50 of the ceramic particles is measured by a laser particle size analyzer (using deionized water as a dispersant); the average pore size of the ceramic particles is measured by a gas adsorption-desorption isotherm method.
  • the average particle size and average pore size are shown in Table 2 below.
  • a commercially available PP-PE copolymer microporous film with a thickness of 20 ⁇ m and an average pore size of 80 nm was used as the substrate.
  • the adhesive composition prepared as described above was stirred and mixed in N-methylpyrrolidone (NMP) to obtain a slurry (solid content of 20%).
  • NMP N-methylpyrrolidone
  • the slurry was evenly coated on both surfaces of the substrate, and dried to remove the organic solvent.
  • the coating density of the adhesive composition on the substrate was 0.5 g/m 2 to obtain a separator.
  • PVDF Polyvinylidene fluoride
  • LFP lithium iron phosphate
  • NMP N-methylpyrrolidone
  • ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1 to obtain a mixed solvent, and then LiPF6 is dissolved in the above mixed solvent to obtain an electrolyte, wherein the concentration of LiPF6 is 1 mol/L.
  • the positive electrode sheet, separator, and negative electrode sheet are stacked and wound in order, and pre-pressed (during this process, the separator and the electrode sheet are bonded) to obtain an electrode assembly; the electrode assembly is placed in an outer package, and the above-prepared electrolyte is added. After packaging, standing, formation, aging and other processes, a secondary battery is obtained.
  • Example 6 Except that the average particle diameters of the porous silica particles are changed to 45 nm, 50 nm, 56 nm, 89 nm, 100 nm and 106 nm, respectively, the other steps of Examples 6 to 11 are the same as those of Example 1.
  • Example 12 to 17 are the same as those of Example 2 except that the average pore diameters of the porous silica particles are changed to 0.5 nm, 1 nm, 1.3 nm, 3.8 nm, 5 nm and 5.7 nm, respectively.
  • Comparative Example 5 Except that the polymer is changed from Preparation Example 1 to Comparative Preparation Example C1, and the particles are changed from porous particles to solid (non-porous) particles with the same average particle size, the remaining steps of Comparative Example 5 are the same as those of Example 1.
  • Rb is the bulk resistance of the diaphragm
  • L and S are the thickness and area of the isolation diaphragm to be tested respectively.
  • Example 1 the battery capacity retention rate test process is as follows: at 25°C, the battery prepared in Example 1 is charged to 4.3V at a constant current of 1/3C, then charged to a current of 0.05C at a constant voltage of 4.3V, left for 5 minutes, and then discharged to 2.8V at 1/3C. The obtained discharge capacity is recorded as the initial capacity C 0 . The above steps are repeated for the same battery, and the discharge capacity C n of the battery after the nth cycle is recorded at the same time.
  • the battery capacity retention rate under a specific number of cycles can be used to reflect the difference in cycle performance.
  • the battery capacity retention rate data corresponding to Example 1 in Table 2 is the data measured after 100 cycles under the above test conditions.
  • the test process of the comparative example and other examples is the same as above.
  • the binder composition of the present application improves ionic conductivity and enhances the cycle performance (e.g., capacity retention rate) of the secondary battery.
  • Comparison of Examples 6 to 30 and Comparative Examples 1 to 5 shows that by controlling the content ratio of the polymer to the ceramic particles, as well as the particle size and/or average pore size of the ceramic, the obtained separator has a higher ionic conductivity and a better battery capacity retention rate.

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Abstract

一种粘结剂组合物，包括聚合物和陶瓷颗粒；所述聚合物包含衍生自第一类单体、第二类单体和第三类单体的结构单元，并且所述第一类单体、第二类单体和第三类单体的摩尔比为50至58:40至44:2至6；其中，所述第一类单体选自一种或多种式I的化合物，所述第二类单体选自一种或多种式II的化合物，所述第三类单体选自一种或多种式III的化合物。所述粘结剂提高隔离膜的孔隙率，改善离子电导率并降低内阻，改善二次电池的循环性能。

Description

粘结剂组合物和包含其的隔离膜 技术领域
本申请涉及锂电池技术领域，尤其涉及一种粘结剂组合物以及包含其的隔离膜。本申请还涉及二次电池、电池模块、电池包和用电装置。
背景技术
近年来，随着二次电池的应用范围越来越广泛，二次电池广泛应用于水力、火力、风力和太阳能电站等储能电源系统，以及电动工具、电动自行车、电动摩托车、电动汽车、军事装备、航空航天等多个领域。由于二次电池取得了极大的发展，因此对其能量密度、循环性能和安全性能等也提出了更高的要求。二次电池的隔离膜中常使用粘结剂，但是，现有的粘结剂存在粘性差、容易造成基材堵孔的问题，导致隔离膜的孔隙率变低，离子在隔离膜内的流动性变差，隔离膜内的电阻升高，影响了二次电池的循环性能。
发明内容
为了达到上述目的，本申请提供了一种粘结剂组合物，以及包括该组合物的隔离膜、二次电池、电池包和用电装置。
本申请的第一方面提供了一种粘结剂组合物，包括聚合物和陶瓷颗粒；所述聚合物包含衍生自第一类单体、第二类单体和第三类单体的结构单元，并且所述第一类单体、第二类单体和第三类单体的摩尔比为50至58:40至44:2至6；
所述第一类单体选自一种或多种式I的化合物：
Figure PCTCN2022121639-appb-000001
其中，R 1选自氢原子和直链或支链的C1-6烷基；R 2选自取代或未取代的直链或支链的C1-15烷基、C3-6环烷基和异冰片基，在取代的情况下，取代基选自羟基和C1-6链烷基；
所述第二类单体选自一种或多种式II的化合物：
Figure PCTCN2022121639-appb-000002
其中，R 3选自氢原子和直链或支链的C1-6烷基；
所述第三类单体选自一种或多种式III的化合物：
Figure PCTCN2022121639-appb-000003
其中，R 4选自氢原子和直链或支链的C1-6烷基，并且R 5选自氢原子、羟基C1-6烷基和C1-6烷氧基。本申请的粘结剂组合物粘结效果好，并且可提高隔离膜的孔隙率，改善离子电导率，降低了隔离膜内阻，提升二次电池的循环性能。
在任意实施方式中，R 1选自氢原子和甲基，且R 2选自取代或未取代的直链或支链的C1-6烷基，在取代的情况下，取代基为羟基；和/或R 3选自氢原子和甲基；和/或R 4选自氢原子和甲基，且R 5选自氢原子、羟基C1-4烷基和C1-4烷氧基。
在任意实施方式中，所述第一类单体选自丙烯酸甲酯、丙烯酸乙酯、丙烯酸正丁酯、丙烯酸异丁酯，丙烯酸仲丁酯，丙烯酸叔丁酯，丙烯酸正丙酯，丙烯酸环己酯，丙烯酸月桂酯，丙烯酸-2-乙基己酯，丙烯酸-2-羟基乙酯，丙烯酸-2-羟基丙酯，甲基丙烯酸甲酯，甲基丙烯酸乙酯，甲基丙烯酸正丁酯，甲基丙烯酸-2-乙基己酯，甲基丙烯酸异冰片酯，甲基丙烯酸月桂酯，甲基丙烯酸-2-羟基乙酯，甲基丙烯酸-2羟基丙酯的一种或多种；和/或所述第二类单体为丙烯腈或甲基丙烯腈；和/或所述第三类单体选自丙烯酰胺、N-羟甲基丙烯酰胺和N-丁氧基甲基丙烯酰胺中的一种或多种。
分别进一步选择上述第一类、第二类和/或第三类单体，有助于 改善隔离膜的离子电导率，并提高电池的循环容量保持率。
在任意实施方式中，所述第一类单体、第二类单体和第三类单体的摩尔比为50至57:41至44：2至6。采用上述范围的摩尔比，更有助于粘结剂组合物进一步改善隔离膜的离子电导率，并提高电池的循环容量保持率。
在任意实施方式中，所述聚合物与所述陶瓷颗粒的重量比为40至90:10至60，可选地为50至80:20至50。所述聚合物和陶瓷颗粒的重量比在上述范围内，既能保证粘结剂与隔离膜、极片的粘结效果，又能使隔离膜具有适当的孔隙率和良好的离子电导率。
在任意实施方式中，所述聚合物的重均分子量为60000至120000，可选地为63300至118800。聚合物的重均分子量在上述范围内，能够使本申请的粘结剂组合物在进行粘结时，聚合物能够具有适当的流动性，从而实现良好的粘结效果，进而改善二次电池的循环性能。
在任意实施方式中，所述陶瓷颗粒的平均粒径Dv50为40nm至110nm，可选地为45nm至106nm，更可选为50nm至100nm，再更可选为56nm至89nm。进一步控制陶瓷颗粒的平均粒径，可进一步改善离子电导率和容量保持率。
在任意实施方式中，所述陶瓷颗粒是多孔颗粒，并且所述多孔颗粒的平均孔径为0.3nm至6.0nm，可选地为0.5nm至5.7nm，更可选为1.0nm至5.0nm，再更可选地为1.3nm至3.8nm。选择多孔颗粒材料并控制其平均孔径，有利于在确保隔离膜热稳定性的同时，进一步改善隔离膜的孔隙率和离子电导率，以及二次电池的循环容量保持率。
在任意实施方式中，所述陶瓷颗粒是多孔二氧化硅颗粒。用多孔二氧化硅颗粒可进一步提高隔离膜的孔隙率和离子电导率，降低隔离膜内阻，提升二次电池的循环性能。
在任意实施方式中，所述聚合物包覆在所述陶瓷颗粒上。如此有助于确保粘结剂组合物能够以理想的配比均匀地施加在基材上，以实现改善耐热性能、孔隙率和良好的粘结效果。
本申请的第二方面提供一种隔离膜，所述隔离膜包括基层和设置 于所述基层至少一个表面上的涂覆层，所述涂覆层包含本申请第一方面的粘结剂组合物。本申请的隔离膜能够与极片稳定粘结，并具有提高的孔隙率，改善离子电导率，降低了隔离膜内阻，提升二次电池的循环性能。
本申请的第三方面提供一种二次电池，包括本申请第一方面的粘结，和/或根据本申请第二方面的隔离膜。
本申请的第四方面提供一种电池模块，包括本申请的第三方面的二次电池。
本申请的第五方面提供一种电池包，包括本申请的第四方面的电池模块。
本申请的第六方面提供一种用电装置，包括选自本申请的第三方面的二次电池、本申请的第四方面的电池模块或本申请的第五方面的电池包中的至少一种。
本申请的粘结剂具有良好的粘结性能，还可提高隔离膜的孔隙率，降低了隔离膜内阻，提升二次电池的循环性能。
附图说明
图1是本申请一实施方式的二次电池的示意图。
图2是图1所示的本申请一实施方式的二次电池的分解图。
图3是本申请一实施方式的电池模块的示意图。
图4是本申请一实施方式的电池包的示意图。
图5是图4所示的本申请一实施方式的电池包的分解图。
图6是本申请一实施方式的二次电池用作电源的用电装置的示意图。
附图标记说明：
1电池包；2上箱体；3下箱体；4电池模块；5二次电池；51壳体；52电极组件；53顶盖组件
具体实施方式
以下，适当地参照附图详细说明具体公开了本申请的粘结剂组合 物、隔离膜、二次电池、电池模块、电池包和电学装置的实施方式。但是会有省略不必要的详细说明的情况。例如，有省略对已众所周知的事项的详细说明、实际相同结构的重复说明的情况。这是为了避免以下的说明不必要地变得冗长，便于本领域技术人员的理解。此外，附图及以下说明是为了本领域技术人员充分理解本申请而提供的，并不旨在限定权利要求书所记载的主题。
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110的范围，理解为60-110和80-120的范围也是预料到的。此外，如果列出的最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。在本申请中，除非有其他说明，数值范围“a-b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有步骤可以顺序进行，也可以随机进行，优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，所述提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。
如果没有特别的说明，本申请所提到的“包括”和“包含”表示开放式，也可以是封闭式。例如，所述“包括”和“包含”可以表示还可以包括或包含没有列出的其他组分，也可以仅包括或包含列出的组分。
如果没有特别的说明，在本申请中，术语“或”是包括性的。举例来说，短语“A或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)。
近年来，随着二次电池的应用范围越来越广泛，二次电池广泛应用于水力、火力、风力和太阳能电站等储能电源系统，以及电动工具、电动自行车、电动摩托车、电动汽车、军事装备、航空航天等多个领域。由于二次电池取得了极大的发展，因此对其能量密度、循环性能和安全性能等也提出了更高的要求。作为二次电池的重要部分——隔离膜自然成为技术人员关注的重点之一。现有技术中多采用对隔离膜基材涂覆陶瓷颗粒(例如，氧化物无机颗粒，如二氧化硅、氧化铝、勃姆石等)的方式来改善隔离膜的耐热性、耐刺穿性等，然后在对涂覆有陶瓷颗粒的隔离膜施加粘结剂并将其与极片粘结，进而制备二次电池。但是这样的方式有其缺陷，首先是陶瓷颗粒容易落入基材的孔隙中而降低隔离膜的孔隙率，不利于离子运动；其次是现有粘结剂的粘结效果欠佳。
为解决上述问题，本申请提出一种粘结剂组合物，其包括起到粘结作用的聚合物与改善安全性能的陶瓷颗粒，减轻甚至避免了堵孔现象的发生，并实现良好粘结效果。此外，本申请的粘结剂组合物中的聚合物，由于其单体的选择和比例调控，也有助于改善离子电导率。综上所述，本申请的粘结剂组合物能够提高隔离膜的孔隙率，提高离子电导率，改善二次电池的循环性能。
粘结剂
本申请的一个实施方式中，本申请提出了一种粘结剂组合物，其包括聚合物和陶瓷颗粒，所述聚合物包含衍生自第一类单体、第二类单体和第三类单体的结构单元，并且所述第一类单体、第二类单体和 第三类单体的摩尔比为50至58:40至44:2至6；
所述第一类单体选自一种或多种式I的化合物：
Figure PCTCN2022121639-appb-000004
其中，R 1选自氢原子和直链或支链的C1-6烷基，并且R 2选自取代或未取代的直链或支链的C1-15烷基、C3-6环烷基和异冰片基，在取代的情况下，取代基选自羟基和C1-6链烷基；
所述第二类单体选自一种或多种式II的化合物：
Figure PCTCN2022121639-appb-000005
其中，R 3选自氢原子和直链或支链的C1-6烷基；
所述第三类单体选自一种或多种式III的化合物：
Figure PCTCN2022121639-appb-000006
其中，R 4选自氢原子和直链或支链的C1-6烷基，并且R 5选自氢原子、羟基C1-6烷基和C1-6烷氧基。
本申请的粘结剂组合物粘结效果好，并且可提高隔离膜的孔隙率，改善离子电导率，降低隔离膜内阻，提升二次电池的循环性能。
在本申请的聚合物中，第一类单体是丙烯酸酯类单体，其可改善粘结剂的抗溶胀能力，并且作为分子链段中的柔性单体链段能够调节聚合物的玻璃化转变温度，从而有助于粘结剂组合物发挥良好的粘结作用。第二类单体是丙烯腈类单体，其具有强极性的氰基基团，有助于提高离子电导率。第三类单体是丙烯酰胺类单体，其中的酰胺基团主要作用是起到交联作用，有助于调节聚合物的分子量。上述三类单体的摩尔比要控制在一定范围内，从而使聚合物具有理想的分子量和玻璃化转变温度，从而在保证粘结剂粘结性能的同时，有助于改善离子电导率。
在一些实施方式中，R 1选自氢原子和甲基，且R 2选自取代或未取代的直链或支链的C1-6烷基，在取代的情况下，取代基为羟基。在一些实施方式中，R 3选自氢原子和甲基。在一些实施方式中，R 4选自氢原子和甲基，且R 5选自氢原子、羟基C1-4烷基和C1-4烷氧基。
在一些实施方式中，所述第一类单体选自丙烯酸甲酯、丙烯酸乙酯、丙烯酸正丁酯、丙烯酸异丁酯，丙烯酸仲丁酯，丙烯酸叔丁酯，丙烯酸正丙酯，丙烯酸环己酯，丙烯酸月桂酯，丙烯酸-2-乙基己酯，丙烯酸-2-羟基乙酯，丙烯酸-2-羟基丙酯，甲基丙烯酸甲酯，甲基丙烯酸乙酯，甲基丙烯酸正丁酯，甲基丙烯酸-2-乙基己酯，甲基丙烯酸异冰片酯，甲基丙烯酸月桂酯，甲基丙烯酸-2-羟基乙酯，甲基丙烯酸-2羟基丙酯的一种或多种。在一些实施方式中，所述第二类单体为丙烯腈或甲基丙烯腈。在一些实施方式中，所述第三类单体选自丙烯酰胺、N-羟甲基丙烯酰胺和N-丁氧基甲基丙烯酰胺中的一种或多种。
分别进一步选择上述第一类、第二类和/或第三类单体，有助于改善隔离膜的离子电导率，并提高电池的循环容量保持率。
在一些实施方式中，所述第一类单体、第二类单体和第三类单体的摩尔比为50至57:41至44:2至6。采用上述范围的摩尔比，更有助于粘结剂组合物进一步改善隔离膜的离子电导率，并提高电池的循环容量保持率。
在一些实施方式中，基于所述第一类单体、第二类单体和第三类单体的总摩尔量计，所述第一类单体的摩尔百分含量为50-58mol％，可选地为50-57mol％；可选地，所述第一类单体的摩尔百分含量为50mol％、51mol％、52mol％、53mol％、54mol％、55mol％、56mol％、57mol％或58mol％，或者在上述数值中任意两者组成的范围内。在一些实施方式中，基于所述第一类单体、第二类单体和第三类单体的总摩尔量计，所述第二类单体的摩尔百分含量为40-44mol％，可选地为41-44mol％；可选地，所述第二类单体的摩尔百分含量为40mol％、41mol％、42mol％、43mol％或44mol％，或者在上述数值中任意两者组成的范围内。在一些实施方式中，基于所述第一类单体、 第二类单体和第三类单体的总摩尔量计，所述第三类单体的摩尔百分含量为2-6mol％；可选地，所述第三类单体的摩尔百分含量为2mol％、3mol％、4mol％、5mol％或6mol％，或者在上述数值中任意两者组成的范围内。
在一些实施方式中，所述聚合物与所述陶瓷颗粒的重量比为40至90:10至60，可选地为50至80:20至50。聚合物和陶瓷颗粒的重量比在上述范围内，既能进一步保证粘结剂与隔离膜、极片的粘结效果，又能使隔离膜具有适当的孔隙率和良好的离子电导率。
在一些实施方式中，所述聚合物的重均分子量为60000至120000，可选地为63300至118800。聚合物的重均分子量在上述范围内，能够使本申请的粘结剂组合物在进行粘结时，聚合物能够具有适当的流动性，从而实现良好的粘结效果，进而改善二次电池的循环性能。
在一些实施方式中，所述陶瓷颗粒的平均粒径Dv50为40nm至110nm，可选地为45nm至106nm；可选地，所述陶瓷颗粒的平均粒径Dv50为40nm、45nm、50nm、56nm、70nm、89nm、100nm、106nm或110nm，或者在这些数值中任意两者组成的范围内。可选地，所述陶瓷颗粒的平均粒径Dv50为50nm至100nm，更可选为56nm至89nm。进一步控制陶瓷颗粒的平均粒径，可进一步改善离子电导率和容量保持率。
在本申请中陶瓷颗粒的材料可以是适用的任何本领域常规材料。在一些实施方式中，所述陶瓷颗粒选自氧化铝、勃姆石、二氧化钛和二氧化硅。
在一些实施方式中，所述陶瓷颗粒可以是多孔颗粒或者实心颗粒(也即，无孔颗粒)。在一些实施方式中，所述陶瓷颗粒是多孔颗粒。所述多孔颗粒的平均孔径为0.3nm至6.0nm；可选地，所述平均孔径为0.5nm、1nm、1.3nm、3nm、3.8nm、5nm或5.7nm，或者在这些数值中任意两者组成的范围内。可选地，所述平均孔径为0.5nm至5.7nm，更可选为1.0nm至5.0nm，再更可选地为1.3nm至3.8nm。进一步选择多孔颗粒材料，并且优选地控制其平均孔径，有利于在确保隔离膜热稳定性的同时，更加改善隔离膜的孔隙率和离子电导率， 以及二次电池的循环容量保持率。
在一些实施方式中，所述陶瓷颗粒是多孔二氧化硅颗粒。用该多孔二氧化硅颗粒可进一步提高隔离膜的孔隙率和离子电导率，降低隔离膜内阻，提升二次电池的循环性能。
在一些实施方式中，所述聚合物包覆在所述陶瓷颗粒上。在施用之前，将聚合物包覆在陶瓷颗粒上，从而减少或避免颗粒落入隔离膜孔隙中造成堵孔，同时确保聚合物和陶瓷颗粒能够以理想的配比均匀地施加在基材上，以实现改善耐热性能、孔隙率和良好的粘结效果。在一些实施方式中，所述聚合物包覆在所述多孔二氧化硅颗粒上。
隔离膜
本申请另一方面提供一种隔离膜，所述隔离膜包括基层和设置于所述基层至少一个表面上的涂覆层，所述涂覆层包含本申请的粘结剂。
本申请对隔离膜基层的材料种类没有特别的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构基层。
在一些实施方式中，隔离膜基层的材质可选自玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏二氟乙烯中的至少一种。隔离膜可以是单层薄膜，也可以是多层复合薄膜，没有特别限制。在隔离膜为多层复合薄膜时，各层的材料可以相同或不同，没有特别限制。
二次电池、电池模块、电池包和用电装置
本申请的第三方面提供一种二次电池，包括本申请的粘结剂，和/或本申请的隔离膜。
本申请的第四方面提供一种电池模块，包括上述第三方面的二次电池。
本申请的第五方面提供一种电池包，包括上述第四方面的电池模块。
本申请的第六方面提供一种用电装置，包括选自上述第三方面的二次电池、第四方面的电池模块和第五方面的电池包中的至少一种。
另外，以下适当参照附图对本申请的二次电池、电池模块、电池包和用电装置进行说明。
本申请的一个实施方式中，提供一种二次电池。在一些实施方式 中，所述二次电池是锂离子二次电池。
通常情况下，二次电池包括正极极片、负极极片、电解质和隔离膜。在电池充放电过程中，活性离子在正极极片和负极极片之间往返嵌入和脱出。电解质在正极极片和负极极片之间起到传导离子的作用。隔离膜设置在正极极片和负极极片之间，主要起到防止正负极短路的作用，同时可以使离子通过。
[正极极片]
正极极片包括正极集流体以及设置在正极集流体至少一个表面的正极膜层，所述正极膜层包括本申请第一方面的正极活性材料。
作为示例，正极集流体具有在其自身厚度方向相对的两个表面，正极膜层设置在正极集流体相对的两个表面的其中任意一者或两者上。
在一些实施方式中，所述正极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可采用铝箔。复合集流体可包括高分子材料基层和形成于高分子材料基层至少一个表面上的金属层。复合集流体可通过将金属材料(铝、铝合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，正极活性材料可采用本领域公知的用于电池的正极活性材料。作为示例，正极活性材料可包括以下材料中的至少一种：橄榄石结构的含锂磷酸盐、锂过渡金属氧化物及其各自的改性化合物、钠过渡金属氧化物、聚阴离子型化合物和普鲁士蓝类化合物。但本申请并不限定于这些材料，还可以使用其他可被用作电池正极活性材料的传统材料。这些正极活性材料可以仅单独使用一种，也可以将两种以上组合使用。其中，锂过渡金属氧化物的示例可包括但不限于锂钴氧化物(如LiCoO 2)、锂镍氧化物(如LiNiO 2)、锂锰氧化物(如LiMnO 2、LiMn 2O 4)、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物(如LiNi 1/3Co 1/3Mn 1/3O 2(也可以简称为NCM 333)、LiNi 0.5Co 0.2Mn 0.3O 2(也可以简称为NCM 523)、LiNi 0.5Co 0.25Mn 0.25O 2(也 可以简称为NCM 211)、LiNi 0.6Co 0.2Mn 0.2O 2(也可以简称为NCM 622)、LiNi 0.8Co 0.1Mn 0.1O 2(也可以简称为NCM 811)、锂镍钴铝氧化物(如LiNi 0.85Co 0.15Al 0.05O 2)及其改性化合物等中的至少一种。橄榄石结构的含锂磷酸盐的示例可包括但不限于磷酸铁锂(如LiFePO 4(也可以简称为LFP))、磷酸铁锂与碳的复合材料、磷酸锰锂(如LiMnPO 4)、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中的至少一种。
在一些实施方式中，钠过渡金属氧化物中，过渡金属可以是Mn、Fe、Ni、Co、Cr、Cu、Ti、Zn、V、Zr及Ce中的至少一种。钠过渡金属氧化物例如为Na xM yO 2，其中M为Ti、V、Mn、Co、Ni、Fe、Cr及Cu中的一种或几种，0＜x≤1，0.5＜y≤1.5。在一些实施方式中，正极活性材料可采用Na 0.88Cu 0.24Fe 0.29Mn 0.47O 2。
在一些实施方式中，聚阴离子型化合物可以是具有钠离子、过渡金属离子及四面体型(YO 4) n-阴离子单元的一类化合物。过渡金属可以是Mn、Fe、Ni、Co、Cr、Cu、Ti、Zn、V、Zr及Ce中的至少一种；Y可以是P、S及Si中的至少一种；n表示(YO 4) n-的价态。
在一些实施方式中，聚阴离子型化合物还可以是具有钠离子、过渡金属离子、四面体型(YO 4) n-阴离子单元及卤素阴离子的一类化合物。过渡金属可以是Mn、Fe、Ni、Co、Cr、Cu、Ti、Zn、V、Zr及Ce中的至少一种；Y可以是P、S及Si中的至少一种，n表示(YO 4) n-的价态；卤素可以是F、Cl及Br中的至少一种。
在一些实施方式中，聚阴离子型化合物还可以是具有钠离子、四面体型(YO 4) n-阴离子单元、多面体单元(ZO y) m+及可选的卤素阴离子的一类化合物。Y可以是P、S及Si中的至少一种，n表示(YO  4) n-的价态；Z表示过渡金属，可以是Mn、Fe、Ni、Co、Cr、Cu、Ti、Zn、V、Zr及Ce中的至少一种，m表示(ZO y) m+的价态；卤素可以是F、Cl及Br中的至少一种。
在一些实施方式中，聚阴离子型化合物例如是NaFePO 4、Na 3V 2(PO 4) 3、NaM’PO 4F(M’为V、Fe、Mn及Ni中的一种或几种)及Na 3(VO y) 2(PO 4) 2F 3-2y(0≤y≤1)中的至少一种。
在一些实施方式中，普鲁士蓝类化合物可以是具有钠离子、过渡金属离子及氰根离子(CN -)的一类化合物。过渡金属可以是Mn、Fe、Ni、Co、Cr、Cu、Ti、Zn、V、Zr及Ce中的至少一种。普鲁士蓝类化合物例如为Na aMe bMe’ c(CN) 6，其中Me及Me’各自独立地为Ni、Cu、Fe、Mn、Co及Zn中的至少一种，0＜a≤2，0＜b＜1，0＜c＜1。
在一些实施方式中，正极膜层还可选地包括粘结剂。作为示例，所述粘结剂可以包括聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物及含氟丙烯酸酯树脂中的至少一种。
在一些实施方式中，正极膜层还可选地包括导电剂。作为示例，所述导电剂可以包括超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，可以通过以下方式制备正极极片：将上述用于制备正极极片的组分，例如正极活性材料、导电剂、粘结剂和任意其他的组分分散于溶剂(例如N-甲基吡咯烷酮)中，形成正极浆料；将正极浆料涂覆在正极集流体上，经烘干、冷压等工序后，即可得到正极极片。
[负极极片]
负极极片包括负极集流体以及设置在负极集流体至少一个表面上的负极膜层，所述负极膜层包括负极活性材料。
作为示例，负极集流体具有在其自身厚度方向相对的两个表面，负极膜层设置在负极集流体相对的两个表面中的任意一者或两者上。
在一些实施方式中，所述负极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可以采用铜箔。复合集流体可包括高分子材料基层和形成于高分子材料基材至少一个表面上的金属层。复合集流体可通过将金属材料(铜、铜合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、 聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，负极活性材料可采用本领域公知的用于电池的负极活性材料。作为示例，负极活性材料可包括以下材料中的至少一种：人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂等。所述硅基材料可选自单质硅、硅氧化合物、硅碳复合物、硅氮复合物以及硅合金中的至少一种。所述锡基材料可选自单质锡、锡氧化合物以及锡合金中的至少一种。但本申请并不限定于这些材料，还可以使用其他可被用作电池负极活性材料的传统材料。这些负极活性材料可以仅单独使用一种，也可以将两种以上组合使用。
在一些实施方式中，负极膜层还可选地包括粘结剂。所述粘结剂可选自丁苯橡胶(SBR)、聚丙烯酸(PAA)、聚丙烯酸钠(PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)、聚甲基丙烯酸(PMAA)及羧甲基壳聚糖(CMCS)中的至少一种。
在一些实施方式中，负极膜层还可选地包括导电剂。导电剂可选自超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，负极膜层还可选地包括其他助剂，例如增稠剂(如羧甲基纤维素钠(CMC-Na))等。
在一些实施方式中，可以通过以下方式制备负极极片：将上述用于制备负极极片的组分，例如负极活性材料、导电剂、粘结剂和任意其他组分分散于溶剂(例如去离子水)中，形成负极浆料；将负极浆料涂覆在负极集流体上，经烘干、冷压等工序后，即可得到负极极片。
[电解质]
电解质在正极极片和负极极片之间起到传导离子的作用。本申请对电解质的种类没有具体的限制，可根据需求进行选择。例如，电解质可以是液态的、凝胶态的或全固态的。
在一些实施方式中，所述电解质采用电解液。所述电解液包括电解质盐和溶剂。
在一些实施方式中，电解质盐可选自六氟磷酸锂、四氟硼酸锂、高氯酸锂、六氟砷酸锂、双氟磺酰亚胺锂、双三氟甲磺酰亚胺锂、三 氟甲磺酸锂、二氟磷酸锂、二氟草酸硼酸锂、二草酸硼酸锂、二氟二草酸磷酸锂及四氟草酸磷酸锂、六氟磷酸钠(NaPF 6)、六氟硼酸钠(NaBF 4)、NaN(SO 2F) 2(简写为NaFSI)、NaClO 4、NaAsF 6、NaB(C 2O 4) 2(简写为NaBOB)、NaBF 2(C 2O 4)(简写为NaDFOB)、NaN(SO 2R F) 2和NaN(SO 2F)(SO 2R F)中的一种或多种；其中，R F代表C bF 2b+1，b为1-10范围内的整数，可选为1-3范围内的整数，更可选地，R F为-CF 3、-C 2F 5或-CF 2CF 2CF 3。
在一些实施方式中，溶剂可选自碳酸亚乙酯、碳酸亚丙酯、碳酸甲乙酯、碳酸二乙酯、碳酸二甲酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸亚丁酯、氟代碳酸亚乙酯、甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丁酸甲酯、丁酸乙酯、1,4-丁内酯、环丁砜、二甲砜、甲乙砜及二乙砜中的至少一种。
在一些实施方式中，所述电解液还可选地包括添加剂。例如添加剂可以包括负极成膜添加剂、正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温或低温性能的添加剂等。
在一些实施方式中，正极极片、负极极片和隔离膜可通过卷绕工艺或叠片工艺制成电极组件。
[外包装]
在一些实施方式中，二次电池可以包括外包装，用于封装正极极片、负极极片和电解质。作为一个示例，正极极片、负极极片和隔离膜可经叠片或卷绕形成叠片结构电芯或卷绕结构电芯，电芯封装在外包装内；电解质采用本申请第一方面所述的电解液，电解液浸润于电芯中。二次电池中电芯的数量可以为一个或几个，可以根据需求来调节。
在一个实施方式中，本申请提供一种电极组件。在一些实施方式中，正极极片、负极极片和隔离膜可通过卷绕工艺或叠片工艺制成电极组件。外包装可用于封装上述电极组件及电解质。
在一些实施方式中，二次电池的外包装可以是软包，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。在一些实施方式中，二次电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。
本申请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。例如，图1是作为一个示例的方形结构的二次电池5。
在一些实施方式中，参照图2，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封装于所述容纳腔内。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多个，本领域技术人员可根据具体实际需求进行选择。
在一些实施方式中，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一个或多个，具体数量本领域技术人员可根据电池模块的应用和容量进行选择。
图3是作为一个示例的电池模块4。参照图3，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。
在一些实施方式中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以为一个或多个，具体数量本领域技术人员可根据电池包的应用和容量进行选择。
图4和图5是作为一个示例的电池包1。参照图4和图5，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。
另外，本申请还提供一种用电装置，所述用电装置包括本申请提供的二次电池、电池模块、或电池包中的至少一种。所述二次电池、电池模块、或电池包可以用作所述用电装置的电源，也可以用作所述用电装置的能量存储单元。所述用电装置可以包括移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等，但不限于此。
作为所述用电装置，可以根据其使用需求来选择二次电池、电池模块或电池包。
图6是作为一个示例的用电装置。该用电装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该用电装置对二次电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用二次电池作为电源。
实施例
以下，说明本申请的实施例。下面描述的实施例是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试剂或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。
1.聚合物的制备
制备例1
在室温下，按照摩尔比50:44:6，称取丙烯酸甲酯60.92g、丙烯腈33.04g和丙烯酰胺6.04g，加入到装有机械搅拌器、温度计和冷凝管的500mL四口烧瓶中，再加入3g十二烷基硫酸钠乳化剂、1g过硫酸铵引发剂和120g去离子水，以1600rpm的转速搅拌乳化30min，然后在氮气保护下升温至75℃反应4h，调节pH值为6～8，立即降温至40℃以下出料，得到聚合物1。
制备例2～5
制备例2～5的制备步骤与制备例1相同，而不同之处在于三种单 体的摩尔比分别为51:43:6、52:42:6、53:41:6和54:40:6，并且三种单体质量共计100g，制备得到聚合物2～5。
制备例6～10
制备例6中，在室温下，按照摩尔比51:44:5，称取丙烯酸正丁酯69.71g、丙烯腈24.90g和N-羟甲基丙烯酰胺5.39g，其余步骤与制备例1相同，得到聚合物6。
制备例7～10中，上述三种单体的摩尔比分别为52:43:5、53:42:5、54:41:5、55:40:5，并且三种单体质量共计100g，其余步骤与制备例1相同，得到聚合物7～10。
制备例11～15
制备例11中，在室温下，按照摩尔比52:44:4，称取甲基丙烯酸乙酯68.42g、丙烯腈26.91g和N-羟甲基丙烯酰胺4.66g；其余步骤与制备例1相同，得到聚合物11。
制备例12～15中，上述三种单体的摩尔比分别为53:43:4、54:42:4、55:41:4、56:40:4，并且三种单体质量共计100g，其余步骤与制备例1相同，得到聚合物12～15。
制备例16～20
制备例16中，在室温下，按照摩尔比53:44:3，称取甲基丙烯酸-2-羟基乙酯67.94g、甲基丙烯腈29.08g和N-丁氧基甲基丙烯酰胺2.99g；其余步骤与制备例1相同，得到聚合物16。
制备例17～20中，上述三种单体的摩尔比分别为54:43:3、55:42:3、56:41:3、57:40:3，并且三种单体质量共计100g，其余制备步骤与制备例1相同，得到聚合物17～20。
制备例21～25
制备例21中，在室温下，按照摩尔比54:44:2，称取甲基丙烯酸-2-羟基丙酯70.44g、甲基丙烯腈26.71g和N-丁氧基甲基丙烯酰胺2.85g；其余制备步骤与制备例1相同，得到聚合物21。
制备例22～25中，上述三种单体的摩尔比分别为55:43:2、56:42:2、57:41:2、58:40:2，并且三种单体质量共计100g，其余制备步骤与制备例1相同，得到聚合物22～25。
制备例26
制备例26中，在室温下，按照摩尔比52:42:6，称取丙烯酸环己酯75.13g，丙烯腈20.88g，丙烯酰胺4.00g，其余制备步骤与制备例1相同，得到聚合物26。
制备例27
制备例27中，在室温下，按照摩尔比57:40:3，称取甲基丙烯酸异冰片酯80.07g，甲基丙烯腈16.95g，N-丁氧基甲基丙烯酰胺2.98g，其余制备步骤与制备例1相同，得到聚合物27。
对比制备例1
在室温下，按照摩尔比60:32:8，称取丙烯酸甲酯69.50g、丙烯腈22.85g和丙烯酰胺7.65g；其余步骤与制备例1相同，得到聚合物C1。
对比制备例2
在室温下，按照摩尔比60:40，称取甲基丙烯酸-2-羟基乙酯74.42g和甲基丙烯腈25.58g；其余步骤与制备例1相同，得到聚合物C2。
采用Waters 1515凝胶渗透色谱仪测定上述制备例和对比制备例所得到的聚合物1-27和对比聚合物1-2的重均分子量；其中，流动相为N,N-二甲基甲酰胺，标样为具有窄分子量分布的线性聚甲基丙烯酸甲酯聚合物，溶剂流速为1.0ml/min。
表1示出了上述制备例1-27和对比制备例1-2中的单体及其摩尔比，以及最终得到的聚合物的重均分子量。
表1
Figure PCTCN2022121639-appb-000007
Figure PCTCN2022121639-appb-000008
Figure PCTCN2022121639-appb-000009
本申请中，以下实施例中的陶瓷颗粒均为市售可得的。采用激光粒度分析仪(以去离子水为分散剂)测定陶瓷颗粒的平均粒径Dv50；采用气体吸附-脱附等温线法测定陶瓷颗粒的平均孔径。平均粒径和平均孔径示于下表2中。
实施例1
1.粘结剂组合物的制备
按照聚合物与多孔二氧化硅颗粒的质量比为75:25，向750g由制备例1得到的聚合物1中加入250g多孔二氧化硅颗粒和1kg去离子水，室温条件下搅拌1小时，经喷雾干燥，则聚合物均匀包覆在多孔二氧化硅颗粒表面，然后球磨粉碎，得到本申请的粘结剂组合物。上述采用的多孔二氧化硅颗粒的平均粒径Dv50为70nm，平均孔径为2.5nm，如表2所示。
2.隔离膜的制备
采用市售的厚度为20μm、平均孔径为80nm的PP-PE共聚物微孔薄膜(来自卓高电子科技公司，型号20)作为基材。将如上文制备的粘结剂组合物于N-甲基吡咯烷酮(NMP)中搅拌混合均匀，得到浆料(固含量为20％)。将浆料均匀涂布在基材的两个表面上，干燥除去有机溶剂，粘结剂组合物在基材上的涂布密度为0.5g/m 2，得到隔离膜。
3.正极极片的制备
将聚偏二氟乙烯(PVDF)、磷酸铁锂(LFP)、导电剂碳黑、N-甲基吡咯烷酮(NMP)按质量比为1.2:58.38:0.42:40，充分搅拌混合均匀后制备成正极浆料。将该正极浆料以200g/m 2的负载量均匀涂覆在正极集流体铝箔的一个表面上，之后经过烘干、冷压、分切，得到正极极片。
4.负极极片的制备
将人造石墨、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC-Na)按照质量比为96.2:1.0:1.6:1.2，加入去离子水中，充分搅拌混合均匀后制备成负极浆料(固含量为63％)。将该负极浆料以98g/m 2的负载量涂覆在负极集流体铜箔的一个表面上，之后经过烘干、冷压、分切，得到负极极片。
5.电解液的制备
在25℃的温度下，将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按体积比1:1:1混合得到混合溶剂，然后将LiPF 6溶解在上述混合溶剂中，得到电解液，其中LiPF 6的浓度为1mol/L。
6.二次电池的制备
将上述正极极片、隔离膜、负极极片按顺序堆叠并卷绕，进行预压成型(这个过程中，隔离膜与极片发生粘结)得到电极组件；将电极组件放入外包装中，加入上述制备的电解液，经封装、静置、化成、老化等工序后，得到二次电池。
实施例2
如下表2所示，按照聚合物与二氧化硅60:40的质量比，向600g由制备例11得到的聚合物11中加入400g多孔二氧化硅颗粒和1kg 去离子水，室温条件下搅拌1小时，经喷雾干燥，球磨粉碎，则聚合物均匀包覆在多孔二氧化硅颗粒表面，得到粘结剂组合物；上述多孔二氧化硅颗粒的平均粒径为80nm，平均孔径为3.0nm。其余步骤与实施例1相同。
实施例3～5
除聚合物分别为制备例24得到的聚合物24、制备例26得到的聚合物26和制备例27得到的聚合物27外，实施例3～5的其余步骤与实施例1相同。
实施例6～11
除多孔二氧化硅颗粒平均粒径分别更改为45nm、50nm、56nm、89nm、100nm和106nm外，实施例6～11的其他步骤与实施例1相同。
实施例12～17
除多孔二氧化硅颗粒平均孔径分别更改为0.5nm、1nm、1.3nm、3.8nm、5nm和5.7nm外，实施例12～17的其他步骤与实施例2相同。
实施例18～21
除聚合物与多孔二氧化硅颗粒的质量比分别更改为40:60、50:50、75:25、80:20、90:10外，实施例18～21的其他步骤与实施例3相同。
实施例22～27
除了将多孔二氧化硅颗粒变更为不同粒径的实心(无孔)二氧化硅颗粒之外，实施例22～27的其余步骤与实施例1相同。
对比例1～2
除了将聚合物由制备例1更改为对比制备例1和对比制备例2之外，对比例1～2的其余步骤与实施例1相同。
对比例3～4
除了将聚合物由制备例11更改为对比制备例1和对比制备例2之外，对比例3～4的其余步骤与实施例2相同。
对比例5
除了将聚合物由制备例1更改为对比制备例C1，并且将颗粒由多孔颗粒变更为平均粒径相同的实心(无孔)颗粒之外，对比例5的 其余步骤与实施例1相同。
测试方法：
1.隔离膜离子电导率测试
(1)制备测试用2025型纽扣电池：在真空手套箱中，向电池负极壳中放入锂片，向其中加入150μL的上述电解液，再放入上述制备的隔离膜(面积为3.14cm 2，厚度为12μm)使其紧贴锂片，再加入25μL上述电解液，最后在其上放置上述正极极片，封装。将组装好的纽扣电池从真空手套箱里取出，放置24h，以进行下一步的测试。
(2)测试：在电化学工作站，在10 -1～10 6Hz的频率范围内进行测试，得到隔离膜电阻Rb，并通过以下公式计算离子电导率σ(单位：S·cm -1)：
Figure PCTCN2022121639-appb-000010
其中：Rb为隔膜的本体电阻，L和S分别为待测隔离膜的厚度和面积。
2.电池循环性能/容量保持率测试
以实施例1为例，电池容量保持率测试过程如下：在25℃下，将实施例1中制备得到的电池，以1/3C恒流充电至4.3V，再以4.3V恒定电压充电至电流为0.05C，搁置5min，再以1/3C放电至2.8V，所得放电容量记为初始容量C 0，对上述同一个电池重复以上步骤，并同时记录循环第n次后电池的放电容量C n，则每次循环后电池容量保持率Pn＝C n/C 0*100％。即可用特定循环次数下的电池容量保持率来体现循环性能的差异。
表2中实施例1对应的电池容量保持率数据是在上述测试条件下循环100次之后测得的数据。对比例以及其他实施例的测试过程同上。
以上测试结果请见表2。
表2
Figure PCTCN2022121639-appb-000011
Figure PCTCN2022121639-appb-000012
Figure PCTCN2022121639-appb-000013
由上表2中所示的各个实施例可知，本申请的粘结剂组合物改善离子电导率，提升二次电池的循环性能(如，容量保持率)。对比实施例6～30和对比例1～5可知，控制聚合物与陶瓷颗粒的含量比例，以及陶瓷可的粒径和/或平均孔径，所得到的隔离膜的离子电导率较高，电池容量保持率较好。
需要说明的是，本申请不限定于上述实施方式。上述实施方式仅为示例，在本申请的技术方案范围内具有与技术思想实质相同的构成、发挥相同作用效果的实施方式均包含在本申请的技术范围内。此外，在不脱离本申请主旨的范围内，对实施方式施加本领域技术人员能够想到的各种变形、将实施方式中的一部分构成要素加以组合而构筑的其它方式也包含在本申请的范围内。

Claims (15)

  1. 一种粘结剂组合物，包括聚合物和陶瓷颗粒；所述聚合物包含衍生自第一类单体、第二类单体和第三类单体的结构单元，并且所述第一类单体、第二类单体和第三类单体的摩尔比为50至58:40至44：2至6；
    所述第一类单体选自一种或多种式I的化合物：
    Figure PCTCN2022121639-appb-100001
    其中，R 1选自氢原子和直链或支链的C1-6烷基，并且R 2选自取代或未取代的直链或支链的C1-15烷基、C3-6环烷基和异冰片基，在取代的情况下，取代基选自羟基和C1-6链烷基；
    所述第二类单体选自一种或多种式II的化合物：
    Figure PCTCN2022121639-appb-100002
    其中，R 3选自氢原子和直链或支链的C1-6烷基；
    所述第三类单体选自一种或多种式III的化合物：
    Figure PCTCN2022121639-appb-100003
    其中，R 4选自氢原子和直链或支链的C1-6烷基，并且R 5选自氢原子、羟基C1-6烷基和C1-6烷氧基。
  2. 根据权利要求1所述的粘结剂组合物，其中R 1选自氢原子和甲基，且R 2选自取代或未取代的直链或支链的C1-6烷基，在取代的情况下，取代基为羟基；和/或R 3选自氢原子和甲基；和/或R 4选自氢原子和甲基，且R 5选自氢原子、羟基C1-4烷基和C1-4烷氧基。
  3. 根据权利要求1或2所述的粘结剂组合物，其中所述第一类 单体选自丙烯酸甲酯、丙烯酸乙酯、丙烯酸正丁酯、丙烯酸异丁酯，丙烯酸仲丁酯，丙烯酸叔丁酯，丙烯酸正丙酯，丙烯酸环己酯，丙烯酸月桂酯，丙烯酸-2-乙基己酯，丙烯酸-2-羟基乙酯，丙烯酸-2-羟基丙酯，甲基丙烯酸甲酯，甲基丙烯酸乙酯，甲基丙烯酸正丁酯，甲基丙烯酸-2-乙基己酯，甲基丙烯酸异冰片酯，甲基丙烯酸月桂酯，甲基丙烯酸-2-羟基乙酯，甲基丙烯酸-2羟基丙酯的一种或多种；和/或
    所述第二类单体为丙烯腈或甲基丙烯腈；和/或
    所述第三类单体选自丙烯酰胺、N-羟甲基丙烯酰胺和N-丁氧基甲基丙烯酰胺中的一种或多种。
  4. 根据权利要求1至3中任一项所述的粘结剂组合物，其中所述第一类单体、第二类单体和第三类单体的摩尔比为50至57:41至44：2至6。
  5. 根据权利要求1至4中任一项所述的粘结剂组合物，其中所述聚合物与所述陶瓷颗粒的重量比为40至90:10至60，可选地为50至80:20至50。
  6. 根据权利要求1至5中任一项所述的粘结剂组合物，其中所述聚合物的重均分子量为60000至120000，可选地为63300至118800。
  7. 根据权利要求1至6中任一项所述的粘结剂组合物，其中所述陶瓷颗粒的平均粒径Dv50为40nm至110nm，可选地为45nm至106nm，更可选为50nm至100nm，再更可选为56nm至89nm。
  8. 根据权利要求1至7中任一项所述的粘结剂组合物，其中所述陶瓷颗粒是多孔颗粒，并且所述多孔颗粒的平均孔径为0.3nm至6.0nm，可选地为0.5nm至5.7nm，更可选为1.0nm至5.0nm，再更可选地为1.3nm至3.8nm。
  9. 根据权利要求1至8中任一项所述的粘结剂组合物，其中所述陶瓷颗粒是多孔二氧化硅颗粒。
  10. 根据权利要求1至9中任一项所述的粘结剂组合物，其中所述聚合物包覆在所述陶瓷颗粒上。
  11. 一种隔离膜，所述隔离膜包括基层和设置于所述基层至少一个表面上的涂覆层，其中所述涂覆层包含权利要求1至10中任一项 所述的粘结剂组合物。
  12. 一种二次电池，包括权利要求1至10中任一项所述的粘结剂组合物，和/或权利要求11所述的隔离膜。
  13. 一种电池模块，包括权利要求12所述的二次电池。
  14. 一种电池包，包括权利要求13所述的电池模块。
  15. 一种用电装置，包括选自权利要求12所述的二次电池、权利要求13所述的电池模块和权利要求14所述的电池包中的至少一种。
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