WO2023197255A1 - 隔膜及其制备方法、二次电池及装置 - Google Patents

隔膜及其制备方法、二次电池及装置 Download PDF

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WO2023197255A1
WO2023197255A1 PCT/CN2022/086860 CN2022086860W WO2023197255A1 WO 2023197255 A1 WO2023197255 A1 WO 2023197255A1 CN 2022086860 W CN2022086860 W CN 2022086860W WO 2023197255 A1 WO2023197255 A1 WO 2023197255A1
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group
alkali metal
separator
ppm
polymer
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PCT/CN2022/086860
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English (en)
French (fr)
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陈文汉
王少飞
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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 CN202280039702.3A priority Critical patent/CN117413426A/zh
Priority to PCT/CN2022/086860 priority patent/WO2023197255A1/zh
Priority to EP22936903.8A priority patent/EP4376201A1/en
Publication of WO2023197255A1 publication Critical patent/WO2023197255A1/zh
Priority to US18/517,182 priority patent/US20240113389A1/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
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • 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
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/20—Manufacture of shaped structures of ion-exchange resins
    • C08J5/22—Films, membranes or diaphragms
    • C08J5/2287—After-treatment
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • 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
    • 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
    • H01M50/449—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
    • 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
    • C08J2325/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Derivatives of such polymers
    • C08J2325/02—Homopolymers or copolymers of hydrocarbons
    • C08J2325/04—Homopolymers or copolymers of styrene
    • C08J2325/08—Copolymers of styrene
    • 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 relates to the field of battery technology, and in particular to a separator and its preparation method, secondary batteries and devices.
  • secondary batteries are widely used in energy storage power systems such as hydraulic, thermal, wind and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, Military equipment, aerospace and other fields. Due to the great development of secondary batteries, higher requirements have been put forward for their energy density, cycle performance and safety performance.
  • the lithium-ion batteries exhibit one or more improved properties.
  • the lithium-ion batteries exhibit reduced performance.
  • DC internal resistance another example of lithium-ion batteries, shows improved cycle retention.
  • the first aspect of the present application is a separator, which includes a microporous layer, the microporous layer includes an alkali metal-containing polymer, the alkali metal-containing polymer includes a polymer chain, and the polymer chain contains a third a first group and a second group;
  • the first group is selected from an organic acid alkali metal group, an alcohol alkali metal group, or a combination thereof;
  • the second group is selected from organic acid groups
  • the alkali metal content in the first group is 50-100 ppm (such as 50-60 ppm, 60-70 ppm, 70-80 ppm, 80-90 ppm or 90-100 ppm);
  • the hydrogen content in the second group is 10-50 ppm (eg 10-20 ppm, 20-30 ppm, 30-40 ppm, 40-50 ppm) based on the total mass of the separator.
  • the separators of the present invention include alkali metal-containing polymer components. This separator is used in lithium-ion batteries. During the battery charging and discharging process, the alkali metal-containing polymer can not only improve the lithium ion conductivity of the separator matrix, but also isolate transition metal nickel ions generated by corrosion by the electrolyte from shuttling to the negative electrode surface. , can also selectively block solvated molecules through micropores, thereby slowing down the migration of transition metals Ni, Co, and Mn to the negative electrode during battery storage or use and their catalytic decomposition of the SEI film, thereby improving the battery's capacity retention rate and Reduce the growth rate of battery internal resistance.
  • the alkali metal content in the first group of the alkali metal-containing polymer is critical.
  • the advantage of its content between 50ppm and 100ppm is that a certain alkali metal ion concentration helps to improve the ionic conductivity of the separator. .
  • the hydrogen content in the second group of the alkali metal-containing polymer is critical.
  • the advantage of its content being 10-50 ppm is that a certain hydrogen ion concentration can suppress
  • the electronic conductivity of the separator is high, and too high a hydrogen ion concentration will occupy alkali metal ion sites, which is not conducive to ionic conductivity.
  • the ratio of the alkali metal content of the first group to the hydrogen content of the second group is 1-10:1, such as 1-2:1, 2-3:1, 3-4: 1. 4-5:1, 5-6:1, 6-7:1, 7-8:1, 8-9:1 or 9-10:1.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the alkali metal polymer has a weight average molecular weight of 100-5000.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the polymer chain is selected from polyolefin chains, polyester chains, polyalkylene oxide chains.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the polyolefin chains include polyphenylene olefin chains, polynitrile olefin chains, or combinations thereof.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the polyester chains include polycarboxylate chains.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the polyalkylene oxide chains include polyalkyl glycol chains.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the organic acid alkali metal group is selected from the group consisting of an alkali metal carboxylate group, an alkali metal sulfonate group, an alkali metal nitrate group, an alkali metal phosphate group, an alkali metal borate group, or the like. combination.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the organic acid group is selected from a carboxylic acid group, a sulfonic acid group, a nitric acid group, a phosphonic acid group, a boronic acid group, or a combination thereof.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • one of the polymer chains includes terminal groups and side chain groups, one or more of the side chain groups is the first group, and one or more of the terminal groups group is the second group.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the alkali metal-containing polymer contains cross-linking agent groups, and the cross-linking agent groups account for 0.1 to 10% of the total mass of the alkali metal-containing polymer, such as 0.1% to 1%, 1%-2%, 2%-3%, 3%-4%, 4%-5%, 5%-6%, 6%-7%, 7%-8%, 8%-9% or 9% -10%.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the alkali metal-containing polymer is a free radical polymer.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the alkali metal is selected from lithium, sodium, or potassium.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the polymer chain has the following general formula:
  • R is a C 0-10 group
  • -IO l Li is the first group
  • -IO 1 H is the second group
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the R includes one or more of the following groups: aromatic groups, oxygen-containing groups, and nitrogen-containing groups.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • R is phenyl or substituted phenyl, amide, or hydroxyl.
  • the -IO l Li is -SO 3 Li, -NO 2 Li, -PO 3 Li or -BO 2 Li or -OLi.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the -IO 1 H is -SO 3 H, -NO 2 H, -PO 3 H, or -BO 2 H.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the microporous layer includes a microporous matrix layer and a modified film, the modified film covers at least part of the surface of the microporous matrix layer, and the modified film contains the alkali metal-containing polymer.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the thickness of the modified film is 1-100 nanometers.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved. For example, 1-10 nanometer, 10-20 nanometer, 20-30 nanometer, 30-40 nanometer, 40-50 nanometer, 50-60 nanometer, 60-70 nanometer, 70-80 nanometer, 80-90 nanometer, 90-100 nanometer nanometer.
  • the present application provides a method for preparing a separator for a battery, including
  • microporous matrix layer Provides a microporous matrix layer
  • the modified film contains an alkali metal-containing polymer, the alkali metal-containing polymer includes a polymer chain, and the polymer chain contains a first group and a second group;
  • the first group is selected from an organic acid alkali metal group, an alcohol alkali metal group, or a combination thereof;
  • the second group is selected from organic acid groups
  • the alkali metal content in the first group is 50 ppm-100 ppm;
  • the hydrogen content in the second group is 10 ppm to 50 ppm based on the total mass of the separator.
  • a third aspect of the present application provides a secondary battery, including the separator described in any one of the above.
  • a fourth aspect of the present application provides a device including the above-mentioned secondary battery.
  • the separator of the present invention includes an alkali metal-containing polymer component. This separator is used in lithium-ion batteries. During the battery charging and discharging process:
  • the alkali metal-containing polymer component in the separator exists as an "ion channel", which effectively conducts lithium ions and improves the lithium ion conductivity of the separator matrix.
  • the alkali metal-containing polymer has a specific degree of lithiation and can be effectively combined with the matrix film.
  • the "ion channel" formed by the alkali metal-containing polymer component can isolate transition metals (such as nickel ions) produced by corrosion by the electrolyte from shuttling to the negative electrode surface. After several charge and discharge cycles, the ternary cathode material will decompose to produce transition metal ions.
  • the inventor includes an alkali metal-containing polymer component in the separator, which is equivalent to setting up a specific lithium ion channel in the separator matrix to prevent transition metals and solvated molecules from shuttling to the surface of the negative electrode of the battery, and significantly slow down the impact of transition metals on the SEI of the negative electrode. Decompose to ensure the cycle stability of the battery.
  • the alkali metal-containing polymer component contains a cross-linking agent.
  • the cross-linking agent can effectively guide monomers such as styrene to polymerize on the surface of the separator to form a film, ensuring uniformity and preventing shedding through chemical bonding.
  • this application uses benzoyl peroxide as the initiator of the polymerization reaction.
  • Benzoyl peroxide and styrene monomer have good mutual solubility, and also have a certain cross-linking effect on the surface of the polypropylene separator.
  • divinylbenzene can play a good bridging role and effectively connect the polystyrene and polypropylene separators after monomer polymerization.
  • the separator of this application has good flexibility, stable interface, and is easy to process.
  • the separator of the present application is used in lithium-ion batteries, which can improve the capacity retention rate of the battery and reduce the growth rate of the internal resistance of the battery.
  • Figure 1 shows a schematic structural diagram of preparing a separator according to one embodiment.
  • Figure 2 shows a schematic structural diagram of a battery according to one embodiment.
  • FIG 3 is an overall view and an exploded view of a secondary battery according to an embodiment of the present application.
  • Figure 4 is a schematic diagram of a battery module according to an embodiment of the present application.
  • Figure 5 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 6 is an exploded view of the battery pack according to an embodiment of the present application shown in FIG. 5 .
  • FIG. 7 is a schematic diagram of a power consumption device using a secondary battery as a power source according to an embodiment of the present application.
  • Battery pack 1 upper box 2; lower box 3; battery module 4; secondary battery 5; case 51; electrode assembly 52; top cover assembly 53; separator 10, microporous layer 11, microporous matrix layer 110; The side surface 112 of the microporous matrix layer; the modified film 12; the positive electrode piece 13; the negative electrode piece 14.
  • Ranges disclosed herein are defined in terms of lower and upper limits. A given range is defined by selecting a lower limit and an upper limit that define the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive of the endpoints, and may be arbitrarily combined, that is, any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, understand that ranges of 60-110 and 80-120 are also expected. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2- 3, 2-4 and 2-5.
  • the numerical range “a-b” represents an abbreviated representation of any combination of real numbers between a and b, where a and b are both real numbers.
  • the numerical range “0-5" means that all real numbers between "0-5" have been listed in this article, and "0-5" is just an abbreviation of these numerical combinations.
  • a certain parameter is an integer ⁇ 2
  • 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.
  • step (c) means that step (c) may be added to the method in any order.
  • the method may include steps (a), (b) and (c). , may also include steps (a), (c) and (b), may also include steps (c), (a) and (b), etc.
  • condition "A or B” is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists) ; Or both A and B are true (or exist).
  • Secondary batteries also known as rechargeable batteries or storage batteries, refer to batteries that can be recharged to activate active materials and continue to be used after the battery is discharged.
  • a secondary battery typically includes a positive electrode plate, a negative electrode plate, a separator and an electrolyte.
  • active ions such as lithium ions
  • the separator is placed between the positive electrode piece and the negative electrode piece. It mainly prevents the positive and negative electrodes from short-circuiting and allows active ions to pass through.
  • the electrolyte is between the positive electrode piece and the negative electrode piece and mainly plays the role of conducting active ions.
  • the present application provides a separator comprising a microporous layer comprising an alkali metal-containing polymer, the alkali metal-containing polymer comprising a polymer chain, the polymer chain containing a first group and second group;
  • the first group is selected from an organic acid alkali metal group, an alcohol alkali metal group, or a combination thereof;
  • the second group is selected from organic acid groups
  • the alkali metal content in the first group is 50-100 ppm (such as 50-60 ppm, 60-70 ppm, 70-80 ppm, 80-90 ppm or 90-100 ppm);
  • the hydrogen content in the second group is 10-50 ppm (eg 10-20 ppm, 20-30 ppm, 30-40 ppm, 40-50 ppm) based on the total mass of the separator.
  • the separators of the present invention include alkali metal-containing polymer components. This separator is used in lithium-ion batteries. During the battery charging and discharging process, the alkali metal-containing polymer can not only improve the lithium ion conductivity of the separator matrix, but also isolate transition metal nickel ions generated by corrosion by the electrolyte from shuttling to the negative electrode surface. , can also selectively block solvated molecules through micropores, thereby slowing down the migration of transition metals Ni, Co, and Mn to the negative electrode during battery storage or use and their catalytic decomposition of the SEI film, thereby improving the battery's capacity retention rate and Reduce the growth rate of battery internal resistance.
  • the alkali metal content in the first group of the alkali metal-containing polymer is critical.
  • the advantage of its content between 50ppm and 100ppm is that a certain alkali metal ion concentration helps to improve the ionic conductivity of the separator. .
  • the hydrogen content in the second group of the alkali metal-containing polymer is critical.
  • the advantage of its content being 10-50 ppm is that a certain hydrogen ion concentration can suppress
  • the electronic conductivity of the separator is high, and too high a hydrogen ion concentration will occupy alkali metal ion sites, which is not conducive to ionic conductivity.
  • the alkali metal content in the first group is 50-100 ppm (such as 50-60 ppm, 60-70 ppm, 70-80 ppm, 80-90 ppm or 90-100 ppm);
  • the hydrogen content in the second group is 10-50 ppm (eg 10-20 ppm, 20-30 ppm, 30-40 ppm, 40-50 ppm) based on the total mass of the separator.
  • the alkali metal content in the first group is 0.1% to 10% (for example, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7 %, 8%, 9% or 10%).
  • the hydrogen content in the second group is 0.02% to 0.1% (eg 0.02%, 0.04%, 0.06%, 0.08% or 0.1%) based on the total mass of the alkali metal polymer.
  • the ratio of the alkali metal content of the first group to the hydrogen content of the second group is 1-10:1, such as 1-2:1, 2-3:1, 3-4: 1. 4-5:1, 5-6:1, 6-7:1, 7-8:1, 8-9:1 or 9-10:1.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the alkali metal polymer has a weight average molecular weight of 100-5000.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the polymer chain is selected from polyolefin chains, polyester chains, polyalkylene oxide chains.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the polyolefin chains include polystyrene olefin chains (eg, polystyrene chains), polynitrile olefin chains, or combinations thereof.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the polyester chains include polycarboxylate chains.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the polyalkylene oxide chains include polyalkyl glycol chains.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the organic acid alkali metal group is selected from the group consisting of an alkali metal carboxylate group, an alkali metal sulfonate group, an alkali metal nitrate group, an alkali metal phosphate group, an alkali metal borate group, or the like. combination.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the organic acid group is selected from a carboxylic acid group, a sulfonic acid group, a nitric acid group, a phosphonic acid group, a boronic acid group, or a combination thereof.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the hydrophilic modification is acid treatment or alkali treatment, wherein the acid source for acid treatment comes from one or more of sulfuric acid, nitric acid, phosphoric acid and boric acid; the alkali source for alkali treatment comes from lithium hydroxide, hydrogen One or more of sodium oxide and potassium hydroxide.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • one of the polymer chains includes terminal groups and side chain groups, one or more of the side chain groups is the first group, and one or more of the terminal groups group is the second group.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the alkali metal-containing polymer contains cross-linking agent groups, and the cross-linking agent groups account for 0.1 to 10% of the total mass of the alkali metal-containing polymer.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the cross-linking agent is a combination of benzoyl peroxide and divinylbenzene.
  • Benzoyl peroxide is the most widely used initiator for polymerization reactions. It has good mutual solubility with styrene monomer and has a certain cross-linking effect on the surface of polypropylene separators.
  • divinylbenzene can play a good bridging role and effectively connect the polystyrene and polypropylene separators after monomer polymerization.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the alkali metal-containing polymer is a free radical polymer.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the alkali metal is selected from lithium, sodium, or potassium.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the polymer chain has the following general formula:
  • R is a C 0-10 group
  • -IO l Li is the first group
  • -IO 1 H is the second group
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • x is 1-2, 2-3, 3-4, 4-5, 5-6, 6-7, 7-8, 8-9, or 9-10.
  • y is 0, 1-2, 2-3, 3-4, 4-5, 5-6, 6-7, 7-8, 8-9, or 9-10.
  • z is 1-2, 2-3, 3-4, 4-5, 5-6, 6-7, 7-8, 8-9, or 9-10.
  • the R includes one or more of the following groups: aromatic groups, oxygen-containing groups, and nitrogen-containing groups.
  • the aromatic group is C 6-10 phenyl or substituted phenyl.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the oxygen-containing group is a hydroxyl (alcohol, phenol), ether, aldehyde, ketone, carbonyl, carboxyl, ester, anhydride or nitro group.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • the nitrogen-containing group is amino, cyano, or amide.
  • the separator based on this solution is used in secondary batteries, and the internal resistance and/or cycle performance of the secondary battery are improved.
  • R is phenyl or substituted phenyl, amide, or hydroxyl.
  • the -IO l Li is -SO 3 Li, -NO 2 Li, -PO 3 Li or -BO 2 Li or -OLi.
  • the -IO 1 H is -SO 3 H, -NO 2 H, -PO 3 H, or -BO 2 H.
  • the microporous layer includes a microporous matrix layer and a modified film, the modified film covers at least part of the surface of the microporous matrix layer, and the modified film contains the alkali metal-containing polymer.
  • the thickness of the modified film is 1-100 nanometers.
  • the present application provides a method for preparing a separator for a battery, including
  • microporous matrix layer Provides a microporous matrix layer
  • the modified film contains an alkali metal-containing polymer, the alkali metal-containing polymer includes a polymer chain, and the polymer chain contains a first group and a second group;
  • the first group is selected from an organic acid alkali metal group, an alcohol alkali metal group, or a combination thereof;
  • the second group is selected from organic acid groups
  • the alkali metal content in the first group is 50 ppm-100 ppm;
  • the hydrogen content in the second group is 10 ppm to 50 ppm based on the total mass of the separator.
  • monomers such as styrene, acrylonitrile, vinyl acetate, and ethylene oxide are used to polymerize on the surface of the microporous matrix layer to form a modified film.
  • the above-mentioned monomers have a high degree of polymerizability, and the polymerized products have good flexibility, stable interfaces, and are easy to process.
  • the above-mentioned polymer product contains side groups, which can be hydrophilized through hydrophilic treatment, and then lithiated by exchanging lithium ions.
  • the present application provides a secondary battery including the separator described in any one of the above.
  • the present application provides a device including the above-mentioned secondary battery.
  • the material of the microporous matrix layer can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the separator can be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer can be the same or different.
  • the microporous substrate layer is a polyolefin separator specified in any of GB/T 36363-2018 Polyolefin separators for lithium-ion batteries.
  • the performance/parameters of the separator of the present application are basically consistent with the performance/parameters recorded in GB/T 36363-2018 polyolefin separator for lithium-ion batteries.
  • test method for the separator mentioned in this application can refer to GB/T 36363-2018 Polyolefin separator for lithium-ion batteries.
  • the positive electrode sheet usually includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector.
  • the positive electrode film layer includes a positive electrode active material.
  • a surface treatment composition may be disposed between the positive electrode current collector and the positive electrode film layer.
  • the positive electrode current collector has two surfaces facing each other in its own 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.
  • the metal foil aluminum foil can 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 base layer.
  • the composite current collector can be formed by forming metal materials (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on polymer material substrates (such as polypropylene (PP), polyterephthalate It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the cathode active material may be a cathode active material known in the art for batteries.
  • the cathode active material may include at least one of the following materials: an olivine-structured lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials of batteries can also be used. Only one type of these positive electrode active materials may be used alone, or two or more types may be used in combination.
  • lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO 2 ), lithium nickel oxides (such as LiNiO 2 ), lithium manganese oxides (such as LiMnO 2 , LiMn 2 O 4 ), lithium Nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 (also referred to as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (can also be abbreviated to NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (can also be abbreviated to NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (can also be abbreviated to NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O 2 (also referred to as NCM811), at least one of lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15),
  • lithium-containing phosphates with an olivine structure can include but are not limited to lithium iron phosphate (such as LiFePO 4 (also referred to as LFP)), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), composite materials of lithium manganese phosphate and carbon, manganese phosphate At least one composite material of lithium iron, lithium iron manganese phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 (also referred to as LFP)
  • composite materials of lithium iron phosphate and carbon such as LiMnPO 4
  • LiMnPO 4 lithium manganese phosphate
  • manganese phosphate At least one composite material of lithium iron, lithium iron manganese phosphate and carbon.
  • the positive electrode film layer optionally further includes surface treatment.
  • surface treatments may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer At least one of copolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin.
  • the positive electrode film layer optionally further includes a conductive agent.
  • the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, surface treatment and any other components in a solvent (such as N- Methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode piece 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, where the negative electrode film layer includes a negative electrode active material.
  • a surface treatment composition may be disposed between the negative electrode current collector and the negative electrode film layer.
  • the negative electrode current collector has two opposite surfaces in its own 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.
  • 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 base material.
  • the composite current collector can be formed by forming metal materials (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyterephthalate It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative active material may be a negative active material known in the art for batteries.
  • the negative 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, and the like.
  • 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 battery negative electrode active materials can also be used. Only one type of these negative electrode active materials may be used alone, or two or more types may be used in combination.
  • the negative electrode film layer optionally further includes surface treatment.
  • the surface treatment may be selected from the group consisting of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), polysodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), poly At least one of methacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the negative electrode film layer optionally further includes a conductive agent.
  • the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the negative electrode film layer optionally includes other auxiliaries, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
  • thickeners such as sodium carboxymethylcellulose (CMC-Na)
  • the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as negative active material, conductive agent, surface treatment and any other components in a solvent (such as deionized water ), the negative electrode slurry is formed; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode piece can be obtained.
  • a solvent such as deionized water
  • the electrolyte plays a role in conducting ions between the positive and negative electrodes.
  • the type of electrolyte in this application can be selected according to needs.
  • the electrolyte can be liquid, gel, or completely solid.
  • the electrolyte is liquid and includes an electrolyte salt and a solvent.
  • the electrolyte salt may be selected from the group consisting of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonimide, lithium bistrifluoromethanesulfonimide, trifluoromethane At least one of lithium sulfonate, lithium difluorophosphate, lithium difluoroborate, lithium dioxaloborate, lithium difluorodioxalate phosphate and lithium tetrafluoroxalate phosphate.
  • the solvent may be selected from the group consisting of ethylene carbonate, propylene carbonate, methylethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, Butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate At least one of ester, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • the electrolyte optionally also includes additives.
  • additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain properties of the battery, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.
  • the positive electrode piece, the negative electrode piece and the separator can be made into an electrode assembly through a winding process or a lamination process.
  • the secondary battery may include an outer packaging.
  • the outer packaging can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the secondary battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.
  • the outer packaging of the secondary battery may also be a soft bag, such as a bag-type soft bag.
  • the material of the soft bag may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.
  • FIG. 3 is an overall view and an exploded view of a square-structured secondary battery 5 as an example.
  • the outer package may include a housing 51 and a cover 53 .
  • the housing 51 may include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose a receiving cavity.
  • the housing 51 has an opening communicating with the accommodation cavity, and the cover plate 53 can cover the opening to close the accommodation cavity.
  • the positive electrode piece, the negative electrode piece and the separator can be formed into the electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the containing cavity.
  • the electrolyte soaks into 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 can be assembled into battery modules, and the number of secondary batteries contained in the battery module can be one or more. Those skilled in the art can select the specific number according to the application and capacity of the battery module.
  • FIG. 4 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 .
  • the plurality of secondary batteries 5 can be fixed by fasteners.
  • the battery module 4 may further include a housing having a receiving space in which a plurality of secondary batteries 5 are received.
  • the above-mentioned battery modules can also be assembled into a battery pack.
  • the number of battery modules contained in the battery pack can be one or more. Those skilled in the art can select the specific number according to the application and capacity of the battery pack.
  • 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 2 and a lower box 3 .
  • the upper box 2 can be covered with the lower box 3 and form a closed space for accommodating the battery module 4 .
  • Multiple 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 by the present application.
  • the secondary battery, battery module, or battery pack may be used as a power source for the electrical device, or may be used as an energy storage unit for the electrical device.
  • the electric 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, and 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 can be selected according to its usage requirements.
  • Fig. 7 is an electrical device as an example.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, etc.
  • a battery pack or battery module can be used.
  • the separator of Example 1 was prepared by the following method:
  • the monomer solution is directly coated on both sides of the microporous separator matrix. After leaving it for 10 minutes, it is left to stand for 8 hours under vacuum conditions at 80°C, so that the monomer solution polymerizes on both sides of the matrix to form a polymer modified film (this paper
  • the polymer in this example is polystyrene), and then use acetone to wash away unreacted monomers on the surface of the substrate.
  • the product of the previous step was placed in a hydrophilic treatment agent (a sulfuric acid aqueous solution with a concentration of 1M) and kept at 80°C for 24 hours to graft sulfonic acid groups onto the surface of the modified membrane, then washed with deionized water and then dried.
  • a hydrophilic treatment agent a sulfuric acid aqueous solution with a concentration of 1M
  • the product of the previous step was placed in a 1M LiCO 3 aqueous solution and stirred at 25°C for 24 hours, so that the hydrogen ions of some sulfonic acid groups were replaced by lithium ions, forming a lithium-containing polymer (alkali metal-containing polymer). .
  • FIG. 1 shows a schematic diagram of the separator of the above embodiment.
  • the separator 10 includes a microporous layer 11.
  • the microporous layer 11 includes a microporous matrix layer 110 and a modified film 12.
  • the modified film 12 covers the side surface 112 of the microporous matrix layer.
  • the modified film 112 contains the alkali metal-containing polymer.
  • the alkali metal-containing polymer includes a polymer chain
  • the polymer chain contains a first group and a second group.
  • Examples 2 to 7 and Example 1 lies in the content and/or type of monomer A, monomer B initiator and hydrophilic treatment agent.
  • the specific contents of monomer A, monomer B initiator and hydrophilic treatment agent are shown in Table 1.
  • Example 5 uses a combination of two monomers to replace monomer A in Example 1.
  • the combination of two monomers includes 350 g of styrene and 350 g of vinyl acetate.
  • Comparative Examples 1 to 4 and Example 1 lies in the content and/or type of monomer A, monomer B, monomer C, initiator and hydrophilic treatment agent.
  • the specific contents of monomer A, monomer B, monomer C, and hydrophilic treatment agent initiator are shown in Table 1.
  • Example 1 The difference between the blank example and Example 1 is that a polypropylene (PP) microporous separator without modified membrane is directly used.
  • PP polypropylene
  • lithium-containing polymer contained in the separator is prepared.
  • the general formula of the lithium-containing polymer is as follows:
  • the alkali metal-containing polymer includes a polymer chain containing a first group and a second group
  • the first group is an organic acid alkali metal group (organic acid lithium group IO 1 Li);
  • the second group is an organic acid group (sulfonic acid group IO 1 H)
  • the alkali metal-containing polymers of the Examples and Comparative Examples are shown in Table 2 below.
  • Example 2 and Comparative Examples 1 and 4 the ester side chain will be hydrolyzed during acid treatment to generate -OH side group and acetic acid, and finally lithiated to -O-Li.
  • the role of divinylbenzene as a cross-linking agent is not included in the general formula.
  • NCM nickel cobalt manganese
  • conductive agent carbon black binder polyvinylidene fluoride (PVDF), and N-methylpyrrolidone (NMP) in a weight ratio of 97.36:28.86:2.7:1.1 and mix evenly. , to obtain the positive electrode slurry; then the positive electrode slurry is evenly coated on the positive electrode current collector, and then dried, cold pressed, and cut to obtain the positive electrode piece.
  • PVDF binder polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • SBR binder styrene-butadiene rubber
  • CMC thickener sodium carboxymethylcellulose
  • the positive electrode piece, separator, and negative electrode piece in order so that the separator plays an isolation role between the positive and negative electrode pieces, then wind it to obtain the bare cell, weld the tabs to the bare cell, and put the bare cell
  • the core is put into an aluminum shell and baked at 80°C to remove water.
  • the electrolyte is then injected and sealed to obtain an uncharged battery.
  • the uncharged battery then undergoes processes such as standing, hot and cold pressing, formation, shaping, and capacity testing to obtain the lithium-ion battery products of each embodiment and comparative example.
  • FIG. 2 shows a schematic diagram of the lithium ion battery of the above embodiment.
  • the lithium ion battery includes a positive electrode piece 13 , a negative electrode piece 14 , and a separator 10 located between the positive electrode piece 13 and the negative electrode piece 14 .
  • the battery capacity retention rate test process is as follows: At 25°C, charge the battery to be tested with a constant current of 1/3C to 4.3V, then charge with a constant voltage of 4.3V until the current is 0.05C, leave it aside for 5 minutes, and then charge it with a constant current of 1/3C Discharge to 2.8V, and the resulting capacity is recorded as the initial capacity C0. Repeat the above steps for the same battery, and at the same time record the discharge capacity Cn of the battery after the nth cycle.
  • the battery capacity retention rate data in Table 3 is the data measured after 100 cycles under the above test conditions, that is, the value of P100.
  • the battery internal resistance growth rate Q100 in Table 3 (DCR n -DCR 1 )/DCR 1 ⁇ 100%.
  • the data in Table 3 are measured after 100 cycles under the above test conditions.
  • the membrane sample was processed by cryoion milling (CP) to obtain the cross section.
  • the processing conditions were -20°C and 3kV for 1 hour.
  • the cross section was observed in a scanning electron microscope (SEM), and the thickness of the modified film was measured.
  • Lithium content C m ⁇ 1 ⁇ 10 -3 ⁇ 25 (unit: ppm)
  • the alkali metal (lithium) content in the first group is 50 ppm-100 ppm; the second group The hydrogen content in it is 10ppm-50ppm.
  • the separators of Examples 1 to 7 are used in lithium-ion batteries, and the lithium-ion batteries exhibit significantly reduced battery internal resistance and significantly improved battery capacity retention.
  • the alkali metal content in the first group is not within the range of 50ppm-100ppm or the hydrogen content in the second group is not within the range of 10ppm-50ppm.
  • the separators of Comparative Examples 1 to 4 were used for lithium ion batteries, and the improvement in the battery internal resistance and battery capacity retention rate of the lithium ion battery was not as good as that of Examples 1 to 7.
  • the present application provides a separator, which includes a microporous layer, the microporous layer includes an alkali metal-containing polymer, the alkali metal-containing polymer includes a polymer chain, and the polymer chain contains a first group and second group;
  • the first group is selected from an organic acid alkali metal group, an alcohol alkali metal group, or a combination thereof;
  • the second group is selected from organic acid groups
  • the alkali metal content in the first group is 50 ppm-100 ppm;
  • the hydrogen content in the second group is 10 ppm to 50 ppm based on the total mass of the separator.
  • the separator is used in lithium-ion batteries, which exhibit significantly reduced battery internal resistance and significantly improved battery capacity retention.

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Abstract

本申请提供了隔膜及其制备方法、二次电池及装置。隔膜包括微孔层，该微孔层包括含碱金属聚合物，所述含碱金属聚合物包括聚合物链，所述聚合物链含有第一基团和第二基团；(a)所述第一基团选自有机酸碱金属基团、醇碱金属基团、或其组合；(b)所述第二基团选自有机酸基团；基于所述隔膜的总质量，所述第一基团中的碱金属含量为50ppm-100ppm；基于所述隔膜的总质量，所述第二基团中的氢含量为10ppm-50ppm。

Description

隔膜及其制备方法、二次电池及装置 技术领域
本申请涉及电池技术领域，尤其涉及一种隔膜及其制备方法、二次电池及装置。
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。
相关技术在二次电池用聚烯烃隔膜的表面负载各种改性物质或涂层，以改善隔膜在二次电池中的应用性能。但是，本领域仍需要性能更好的隔膜。
发明内容
本申请是鉴于上述课题而进行的，其目的在于，提供一种新型隔膜，该隔膜用于锂离子电池，锂离子电池表现出一项或多项改进的性能，例如锂离子电池表现出降低的直流内阻，再例如锂离子电池表现出提高的循环保持率。
为了达到上述目的，本申请第一方面一种隔膜，其包括微孔层，该微孔层包括含碱金属聚合物，所述含碱金属聚合物包括聚合物链，所述聚合物链含有第一基团和第二基团；
(a)所述第一基团选自有机酸碱金属基团、醇碱金属基团、或其组合；
(b)所述第二基团选自有机酸基团；
基于所述隔膜的总质量，所述第一基团中的碱金属含量为50ppm-100ppm(例如50-60ppm、60-70ppm、70-80ppm、80-90ppm或90-100ppm)；
基于所述隔膜的总质量，所述第二基团中的氢含量为10ppm-50ppm(例如10-20ppm、20-30ppm、30-40ppm、40-50ppm)。
不受理论限制，本发明的隔膜包括含碱金属聚合物成分。该隔膜用于锂离子电池，在电池充放电过程中，含碱金属聚合物不仅能够提高隔膜基体的锂离子传导率，还能隔绝因被电解液腐蚀而产生的过渡金属镍离子穿梭到负极表面，还能够通过微孔选择性阻挡溶剂化分子，进而能够减缓电池存储或使用过程中过渡金属Ni、Co、Mn向负极的迁移及其对SEI膜的催化分解，从而改善电池的容量保持率和降低电池内阻增长率。
基于所述隔膜的总质量，含碱金属聚合物的第一基团中的碱金属含量是关键的，其含量在50ppm-100ppm的优点是一定的碱金属离子浓度有助于改善隔膜的离子电导。
基于所述隔膜的总质量，含碱金属聚合物的第二基团中的氢含量是关键的，其含量在10-50ppm的优点是一定的氢离子浓度由于其本身的给质子特性，能够抑制隔膜电子电导，而过高的氢离子浓度会占据碱金属离子位点，不利于离子电导。
在一些实施方式中，第一基团的碱金属含量和所述第二基团的氢含量的比为1-10:1，例如1-2:1、2-3:1、3-4:1、4-5:1、5-6:1、6-7:1、7-8:1、8-9:1或9-10:1。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述碱金属聚合物的重均分子量为100-5000。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述聚合物链选自聚烯烃链、聚酯链、聚环氧烷基链。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述聚烯烃链包括聚苯烯烃链、聚腈烯烃链或其组合。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述聚酯链包括聚羧酸酯链。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述聚环氧烷基链包括聚烷基乙二醇链。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述有机酸碱金属基团选自羧酸碱金属基团、磺酸碱金属基团、硝酸碱金属基团、磷酸碱金属基团、硼酸碱金属基团或其组合。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述有机酸基团选自羧酸基团、磺酸基团、硝酸基团、膦酸基团、硼酸基团或其组合。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，一个所述聚合物链包括端基基团和侧链基团，一个或多个所述侧链基团为所述第一基团，一个或多个所述端基基团为所述第二基团。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述含碱金属聚合物含有交联剂基团，所述交联剂基团占所述含碱金属聚合物总质量的0.1～10％，例如0.1％-1％、1％-2％、2％-3％、3％-4％、4％-5％、5％-6％、6％-7％、7％-8％、8％-9％或9％-10％。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述含碱金属聚合物为自由基聚合物。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述碱金属选自锂、钠或钾。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述聚合物链具有以下通式：
Figure PCTCN2022086860-appb-000001
其中，R为C 0-10基，-IO lLi为所述第一基团，-IO 1H为所述第二基团；
其中，x＝1-10，y＝0-10，z＝1-10。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述R包括以下一种或多种基团：芳香基团、含氧基团、含氮基团。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述R为苯基或取代苯基、酰胺基、或羟基。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述-IO lLi为-SO 3Li、-NO 2Li、-PO 3Li或-BO 2Li或-OLi。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述-IO 1H为-SO 3H、-NO 2H、-PO 3H或-BO 2H。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述微孔层包括微孔基体层和修饰膜，所述修饰膜覆盖所述微孔基体层的至少部分表面，所述修饰膜含有所述含碱金属聚合物。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述修饰膜的厚度为1-100纳米。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。例如，1-10纳米、10-20纳米、20-30纳米、30-40纳米、40-50纳米、50-60纳米、60-70纳米、70-80纳米、80-90纳米、90-100纳米。
在第二方面，本申请提供一种用于电池的隔膜的制备方法，包括
提供微孔基体层；
在所述微孔基体层的至少部分表面形成修饰膜；
所述修饰膜含有含碱金属聚合物，所述含碱金属聚合物包括聚合物链，所述聚合物链含有第一基团和第二基团；
(a)所述第一基团选自有机酸碱金属基团、醇碱金属基团、或其组合；
(b)所述第二基团选自有机酸基团；
基于所述隔膜的总质量，所述第一基团中的碱金属含量为50ppm-100ppm；
基于所述隔膜的总质量，所述第二基团中的氢含量为10ppm-50ppm。
本申请第三方面提供一种二次电池，包括上述任一项所述的隔膜。
本申请第四方面提供一种装置，包括上述二次电池。
有益效果
本申请一项或多项实施方式具有以下一项或多项有益效果：
(1)本发明的隔膜包括含碱金属聚合物成分。该隔膜用于锂离子电池，在电池充放电过程中：
(2)隔膜中的含碱金属聚合物成分作为“离子通道”存在，其有效传导锂离子，提高了隔膜基体的锂离子传导率。含碱金属聚合物具有特定的锂化程度，能够与基体膜有效结合。
(3)含碱金属聚合物成分形成的“离子通道”能隔绝因被电解液腐蚀而产生的过渡金属(如镍离子)穿梭到负极表面。在数次充放电循环后，三元正极材料会分解产生过渡金属离子。而在本发明中，发明人在隔膜包括含碱金属聚合物成分，相当于给隔膜基体设置特定锂离子通道，防止过渡金属与溶剂化分子穿梭到电池负极表面，显著减缓过渡金属对负极SEI的分解，从而保障电池的循环稳定性。
(4)在一些实施方案中，含碱金属聚合物成分中含有交联剂。交联剂能够有效引导苯乙烯等单体在隔膜表面聚合成膜，保证均一性，并通过化学键合防止脱落。
(5)在一些实施方案中，本申请采用过氧化苯甲酰作为聚合反应的引发剂。过氧化苯甲酰与苯乙烯单体具有较好的互溶性，同时在聚丙烯隔膜表面具备一定的交联作用。在此基础上引入二乙烯基苯可以起到很好的桥接作用，有效连结单体聚合后的聚苯乙烯和聚丙烯隔膜。
(6)本申请的隔膜具有良好的柔韧性，稳定界面，易于加工。
(7)本申请的隔膜用于锂离子电池，能够改善电池的容量保持率和降低电池内阻增长率。
附图说明
图1示出一个实施方式制备隔膜的结构示意图。
图2示出一个实施方式的电池的结构示意图。
图3是本申请一实施方式的二次电池整体图及分解图。
图4是本申请一实施方式的电池模块的示意图。
图5是本申请一实施方式的电池包的示意图。
图6是图5所示的本申请一实施方式的电池包的分解图。
图7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：
电池包1；上箱体2；下箱体3；电池模块4；二次电池5；壳体51；电极组件52；顶盖组件53；隔膜10、微孔层11、微孔基体层110；微孔基体层的侧表面112；修饰膜12；正极极片13；负极极片14。
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隔膜及其制备方法、二次电池及装置。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)。
[二次电池]
二次电池又称为充电电池或蓄电池，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、隔膜及电解液。在电池充放电过程中，活性离子(例如锂离子)在正极极片和负极极片之间往返嵌入和脱出。隔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，同时可以使活性离子通过。电解液在正极极片和负极极片之间，主要起到传导活性离子的作用。
[隔膜]
在一些实施方式中，本申请提供一种隔膜，其包括微孔层，该微孔层包括含碱金属聚合物，所述含碱金属聚合物包括聚合物链，所述聚合物链含有第一基团和第二基团；
(a)所述第一基团选自有机酸碱金属基团、醇碱金属基团、或其组合；
(b)所述第二基团选自有机酸基团；
基于所述隔膜的总质量，所述第一基团中的碱金属含量为50ppm-100ppm(例如50-60ppm、60-70ppm、70-80ppm、80-90ppm或90-100ppm)；
基于所述隔膜的总质量，所述第二基团中的氢含量为10ppm-50ppm(例如10-20ppm、20-30ppm、30-40ppm、40-50ppm)。
不受理论限制，本发明的隔膜包括含碱金属聚合物成分。该隔膜用于锂离子电池，在电池充放电过程中，含碱金属聚合物不仅能够提高隔膜基体的锂离子传导率，还能隔绝因被电解液腐蚀而产生的过渡金属镍离子穿梭到负极表面，还能够通过微孔选择性阻挡溶剂化分子，进而能够减缓电池存储或使用过程中过渡金属Ni、Co、Mn向负极的迁移及其对SEI膜的催化分解，从而改善电池的容量保持率和降低电池内阻增长率。
基于所述隔膜的总质量，含碱金属聚合物的第一基团中的碱金属含量是关键的，其含量在50ppm-100ppm的优点是一定的碱金属离子浓度有助于改善隔膜的离子电导。
基于所述隔膜的总质量，含碱金属聚合物的第二基团中的氢含量是关键的，其含量在10-50ppm的优点是一定的氢离子浓度由于其本身的给质子特性，能够抑制隔膜电子电导，而过高的氢离子浓度会占据碱金属离子位点，不利于离子电导。
基于所述隔膜的总质量，所述第一基团中的碱金属含量为50ppm-100ppm(例如50-60ppm、60-70ppm、70-80ppm、80-90ppm或90-100ppm)；
基于所述隔膜的总质量，所述第二基团中的氢含量为10ppm-50ppm(例如10-20ppm、20-30ppm、30-40ppm、40-50ppm)。
基于碱金属聚合物的总质量，所述第一基团中的碱金属含量为0.1％～10％(例如0.5％、1％、2％、3％、4％、5％、6％、7％、8％、9％或10％)。
基于碱金属聚合物的总质量，所述第二基团中的氢含量为0.02％～0.1％(例如0.02％、0.04％、0.06％、0.08％或0.1％)。
在一些实施方式中，第一基团的碱金属含量和所述第二基团的氢含量的比为1-10:1，例如1-2:1、2-3:1、3-4:1、4-5:1、5-6:1、6-7:1、7-8:1、8-9:1或9-10:1。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述碱金属聚合物的重均分子量为100-5000。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述聚合物链选自聚烯烃链、聚酯链、聚环氧烷基链。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述聚烯烃链包括聚苯烯烃链(例如聚苯乙烯链)、聚腈烯烃链或其组合。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述聚酯链包括聚羧酸酯链。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述聚环氧烷基链包括聚烷基乙二醇链。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述有机酸碱金属基团选自羧酸碱金属基团、磺酸碱金属基团、硝酸碱金属基团、磷酸碱金属基团、硼酸碱金属基团或其组合。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述有机酸基团选自羧酸基团、磺酸基团、硝酸基团、膦酸基团、硼酸基团或其组合。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方案中，制备上述隔膜的方法包括对聚烯烃基体膜进行亲水改性，亲水改性后的聚烯烃基体膜表面富含-SO 3H(-NO 2H，-PO 3H或-BO 2H)或-OM(M＝Li，Na或K)基团，通过含锂溶液的浸润加热，可以将聚烯烃表面的H +或M +与Li +交换，实现-SO 3H向-SO 3Li转变的锂化过程。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方案中，亲水改性为酸处理或碱处理，其中酸处理酸源来自于硫酸、硝酸、磷酸和硼酸中的一种或多种；碱处理碱源来自于氢氧化锂、氢氧化钠和氢氧化钾中的一种或多种。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，一个所述聚合物链包括端基基团和侧链基团，一个或多个所述侧链基团为所述第一基团，一个或多个所述端基基团为所述第二基团。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述含碱金属聚合物含有交联剂基团，所述交联剂基团占所述含碱金属聚合物总质量的0.1～10％。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方案中，交联剂为过氧化苯甲酰与二乙烯基苯的组合。过氧化苯甲酰是聚合反应应用最广的引发剂，与苯乙烯单体具有较好的互溶性，同时在聚丙烯隔膜表面具备一定的交联作用。在此基础上引入二乙烯基苯可以起到很好的桥接作用，有效连结单体聚合后的聚苯乙烯和聚丙烯隔膜。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述含碱金属聚合物为自由基聚合物。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述碱金属选自锂、钠或钾。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述聚合物链具有以下通式：
Figure PCTCN2022086860-appb-000002
其中，R为C 0-10基，-IO lLi为所述第一基团，-IO 1H为所述第二基团；
其中，x＝1-10，y＝0-10，z＝1-10。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方案中，x为1-2、2-3、3-4、4-5、5-6、6-7、7-8、8-9或9-10。
在一些实施方案中，y为0、1-2、2-3、3-4、4-5、5-6、6-7、7-8、8-9或9-10。
在一些实施方案中，z为1-2、2-3、3-4、4-5、5-6、6-7、7-8、8-9或9-10。
在上述实施方案中，当R为C 0基时，应当理解为IO 1Li与主链直接链接。
在一些实施方式中，所述R包括以下一种或多种基团：芳香基团、含氧基团、含氮基团。
在一些实施方案中，芳香基团是C 6-10苯基或取代苯基。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方案中，含氧基团是羟基(醇，酚)，醚基，醛基，酮基，羰基，羧基，酯基，酸酐或硝基。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方案中，含氮基团是氨基、氰基或酰胺基。基于此方案的隔膜用于二次电池，二次电池的内阻和/或循环性能得到改善。
在一些实施方式中，所述R为苯基或取代苯基、酰胺基、或羟基。
在一些实施方式中，所述-IO lLi为-SO 3Li、-NO 2Li、-PO 3Li或-BO 2Li或-OLi。
在一些实施方式中，所述-IO 1H为-SO 3H、-NO 2H、-PO 3H或-BO 2H。
在一些实施方式中，所述微孔层包括微孔基体层和修饰膜，所述修饰膜覆盖所述微孔基体层的至少部分表面，所述修饰膜含有所述含碱金属聚合物。
在一些实施方式中，所述修饰膜的厚度为1-100纳米。
在一些实施方式中，本申请提供一种用于电池的隔膜的制备方法，包括
提供微孔基体层；
在所述微孔基体层的至少部分表面形成修饰膜；
所述修饰膜含有含碱金属聚合物，所述含碱金属聚合物包括聚合物链，所述聚合物链含有第一基团和第二基团；
(a)所述第一基团选自有机酸碱金属基团、醇碱金属基团、或其组合；
(b)所述第二基团选自有机酸基团；
基于所述隔膜的总质量，所述第一基团中的碱金属含量为50ppm-100ppm；
基于所述隔膜的总质量，所述第二基团中的氢含量为10ppm-50ppm。
在一些实施方案中，采用苯乙烯，丙烯腈，乙酸乙烯酯，环氧乙烷等单体在微孔基体层的表面聚合，形成修饰膜。上述单体可聚度高，聚合产物具有良好的柔韧性，稳定界面， 易于加工。上述聚合产物含有侧基基团，通过亲水处理可实现亲水基团化，再交换锂离子可实现锂化。
在一些实施方式中，本申请提供一种二次电池，包括上述任一项所述的隔膜。
在一些实施方式中，本申请提供一种装置，包括上述二次电池。
在一些实施方式中，微孔基体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。隔膜可以是单层薄膜，也可以是多层复合薄膜。在隔膜为多层复合薄膜时，各层的材料可以相同或不同。
在一些实施方案中，微孔基材层是GB/T 36363-2018锂离子电池用聚烯烃隔膜中规定的任一项的聚烯烃隔膜。
在一些实施方案中，本申请隔膜的性能/参数与GB/T 36363-2018锂离子电池用聚烯烃隔膜记载的性能/参数基本一致。
在一些实施方案中，本申请提及的隔膜的测试方法可以参考GB/T 36363-2018锂离子电池用聚烯烃隔膜。
[正极极片]
正极极片通常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，正极膜层包括正极活性材料。正极集流体和正极膜层之间可设置有表面处理组合物。
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，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。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NCM333)、LiNi 0.5Co 0.2Mn 0.3O 2(也可以简称为NCM523)、LiNi 0.5Co 0.25Mn 0.25O 2(也可以简称为NCM211)、LiNi 0.6Co 0.2Mn 0.2O 2(也可以简称为NCM622)、LiNi 0.8Co 0.1Mn 0.1O 2(也可以简称为NCM811)、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，正极膜层还可选地包括表面处理。作为示例，表面处理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，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、表面处理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。负极集流体和负极膜层之间可设置有表面处理组合物。
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，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。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。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表面处理。作为示例，表面处理可选自丁苯橡胶(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。作为示例，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、表面处理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，电解质为液态的，且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中的至少一种。
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，电解液还可选地包括添加剂。作为示例，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、负极极片和隔膜可通过卷绕工艺或叠片工艺制成电极组件。
在一些实施方式中，二次电池可包括外包装。该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硬壳，例如硬塑料壳、铝壳、钢壳等。二次电池的外包装也可以是软包，例如袋式软包。软包的材质可以是塑料，作为塑料，可列举出聚丙烯、聚对苯二甲酸丁二醇酯以及聚丁二酸丁二醇酯等。
本申请对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3是作为一个示例的方形结构的二次电池5的整体图和分解图。
在一些实施方式中，参照图3，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4是作为一个示例的电池模块4。参照图4，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5和图6是作为一个示例的电池包1。参照图5和图6，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7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。
[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。
隔膜的制备
实施例1
实施例1的隔膜由以下方法制备获得：
提供锂离子电池用聚丙烯(PP)微孔隔膜100g，作为微孔隔膜基体。
将7g过氧化苯甲酰(引发剂)和100g对二乙烯基苯(单体B)溶解于700g苯乙烯(单体A)中，搅拌均匀，获得均质的单体溶液。实施例1的单体溶液中，单体A、单体B和引发剂的含量如表1所示。
将单体溶液直接涂覆于微孔隔膜基体的两侧表面，静置10min后，在80℃真空条件下静置8h，使单体溶液在基体的两侧表面聚合形成聚合物修饰膜(本例中聚合物为聚苯乙烯)，然后用丙酮洗去基体表面未反应的单体。
将上一步的产物置于亲水处理剂(浓度1M的硫酸水溶液)中，在80℃保持24h，使修饰膜的表面接枝磺酸基团，然后用去离子水洗涤，然后烘干。
将上一步的产物置于浓度为1M LiCO 3水溶液中，在25℃下搅拌24h，使部分磺酸基团的氢离子被置换为锂离子，形成了含锂聚合物(含碱金属聚合物)。
将上一步产物用去离子水洗涤，然后烘干。产物实施例1的隔膜。
图1示出上述实施例的隔膜的示意图。隔膜10包括微孔层11，该微孔层11包括微孔基体层110和修饰膜12，修饰膜12覆盖所述微孔基体层的侧表面112，修饰膜112含有所述含碱金属聚合物，所述含碱金属聚合物包括聚合物链，所述聚合物链含有第一基团和第二基团。
实施例2～7
实施例2～7与实施例1的区别在于单体A、单体B引发剂和亲水处理剂的含量和/或种类与实施例1不同。具体的单体A、单体B引发剂和亲水处理剂的含量如表1所示。
特别地，实施例5采用两种单体的组合替换实施例1的单体A，两种单体的组合包括苯乙烯350g和乙酸乙烯酯350g。
对比例1～4
对比例1～4与实施例1的区别在于单体A、单体B、单体C、引发剂和亲水处理剂的含量和/或种类与实施例1不同。具体的单体A、单体B、单体C、和亲水处理剂引发剂的含量如表1所示。
空白例
空白例与实施例1的区别在于直接采用无修饰膜的聚丙烯(PP)微孔隔膜。
Figure PCTCN2022086860-appb-000003
实施例和对比例制备隔膜含有的含锂聚合物，含锂聚合物的通式如下：
Figure PCTCN2022086860-appb-000004
含碱金属聚合物包括聚合物链，所述聚合物链含有第一基团和第二基团；
(a)所述第一基团为有机酸碱金属基团(有机酸锂基团IO 1Li)；
(b)所述第二基团为有机酸基团(磺酸基团IO 1H)
实施例和对比例的含碱金属聚合物如下表2所示。对于实施例2、对比例1、4，酯基侧链在酸处理过程中会发生水解生成-OH侧基和乙酸，最后锂化为-O-Li。另外，二乙烯基苯作为交联剂作用未写进通式。
表2
Figure PCTCN2022086860-appb-000005
Figure PCTCN2022086860-appb-000006
锂离子电池的制备
将实施例1～7和对比例1～5的隔膜应用于锂离子电池。具体方法如下：
将镍钴锰(NCM)三元材料、导电剂碳黑、粘结剂聚偏二氟乙烯(PVDF)、N-甲基吡咯烷酮(NMP)按重量比为97.36：28.86：2.7：1.1搅拌混合均匀，得到正极浆料；之后将正极浆料均匀涂覆于正极集流体上，之后经过烘干、冷压、分切，得到正极极片。
将活性物质人造石墨、导电剂碳黑、粘结剂丁苯橡胶(SBR)、增稠剂羟甲基纤维素钠(CMC)按照重量比为96.2：0.8：0.8：1.2溶于溶剂去离子水中，混合均匀后制备成负极浆料；将负极浆料一次或多次均匀涂覆在负极集流体铜箔上，经过烘干、冷压、分切得到负极极片。
在氩气气氛手套箱中(H 2O<0.1ppm，O 2<0.1ppm)，将有机溶剂碳酸乙烯酯(EC)/碳酸甲乙酯(EMC)按照体积比3/7混合均匀，加入12.5％LiPF 6锂盐溶解于有机溶剂中，搅拌均匀，得到实施例1的电解液。
将正极极片、隔膜、负极极片按顺序叠好，使隔膜处于正、负极片之间起到隔离的作用，然后卷绕得到裸电芯，给裸电芯焊接极耳，并将裸电芯装入铝壳中，并在80℃下烘烤除水，随即注入电解液并封口，得到不带电的电池。不带电的电池再依次经过静置、热冷压、化成、整形、容量测试等工序，获得各实施例和对比例的锂离子电池产品。
图2示出上述实施例的锂离子电池的示意图，锂离子电池包括正极极片13、负极极片14，以及位于正极极片13和负极极片14之间的隔膜10。
分析检测
【电池性能测试】
1、电池容量保持率测试
电池容量保持率测试过程如下：在25℃下，将待测电池，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，所得容量记为初始容量C0。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Cn，则每次循环后电池容量保持率Pn＝Cn/C0*100％，以P1、P2……P100这100个点值为纵坐标，以对应的循环次数为横坐标，得到如附图4所示的实施例1的锰酸锂正极活性材料对应的电池容量保持率与循环次数的曲线图。
该测试过程中，第一次循环对应n＝1、第二次循环对应n＝2、……第100次循环对应 n＝100。表3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，即P100的值。
2、电池直流阻抗(DCR)测试
电池直流阻抗测试过程如下：在25℃下，将实施例1对应的电池，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后，记录电压V1。然后再以1/3C放电30s，记录电压V2，则(V2-V1)/1/3C，得到第一次循环后电池的内阻DCR1。对上述同一个电池重复以上步骤，并同时记录循环第n次后电池的内阻DCR n(n＝1、2、3……100)。
该测试过程中，第一次循环对应n＝1、第二次循环对应n＝2、……第100次循环对应n＝100。表3的电池内阻增长率Q100＝(DCR n-DCR 1)/DCR 1×100％，表3中的数据是在上述测试条件下循环100次之后测得的数据。
【理化性能测试】
1、修饰膜厚度测试
利用冷冻离子研磨(CP)对隔膜样品进行处理获得截面，处理条件为-20℃，3kV处理1h。将截面置于扫描电子显微镜(SEM)中观察，并量取修饰膜的厚度。
2、第一基团的锂含量测试
取1g隔膜样品消融至3mL盐酸和1mL硝酸中，泡3h；加入5mL H 2O，而后小心吸入25mL容量瓶，继续加水洗涤泡瓶，洗涤液吸入容量瓶标定；容量瓶中的溶液经过滤后，留存10mL测电感耦合等离子体发射光谱(ICP-OES)。测试结果为C m，则实际锂含量公式为：
锂含量＝C m×1×10 -3×25(单位：ppm)
3、第二基团的氢含量测试
剪取1g，半径为R(cm)的隔膜置于红外透射仓内，采集背景。常温真空吸附吡啶后，升温至100℃采集样品信号，扣除背景获得隔膜1540cm -1处B酸强度红外光谱图，该处的吸收因子为ε＝1.67cm 2/μmol。测试结果为I m，则实际酸羟基氢含量公式为：
氢含量＝3.14×R 2×I m/4/ε×1000(单位：ppm)
对实施例和对比例的隔膜及应用了隔膜的电池进行上述测试，结果如下表3所示：
表3
Figure PCTCN2022086860-appb-000007
Figure PCTCN2022086860-appb-000008
*在表3中，以空白例测得的数值作为基准值，计算实施例和对比例的相应数值相较于基准值的变化率。
由表1～3所示，实施例1～7的隔膜中，基于所述隔膜的总质量，所述第一基团中的碱金属(锂)含量为50ppm-100ppm；所述第二基团中的氢含量为10ppm-50ppm。实施例1～7的隔膜用于锂离子电池，锂离子电池表现出显著降低的电池内阻和显著提升的电池容量保持率。
对比例1～4的隔膜中，基于所述隔膜的总质量，所述第一基团中的碱金属含量为不在50ppm-100ppm范围内或第二基团中的氢含量不在10ppm-50ppm范围内。对比例1～4的隔膜用于锂离子电池，锂离子电池的电池内阻和电池容量保持率的改善程度不如实施例1～7。
综上所述，本申请提供了一种隔膜，其包括微孔层，该微孔层包括含碱金属聚合物，所述含碱金属聚合物包括聚合物链，所述聚合物链含有第一基团和第二基团；
(a)所述第一基团选自有机酸碱金属基团、醇碱金属基团、或其组合；
(b)所述第二基团选自有机酸基团；
基于所述隔膜的总质量，所述第一基团中的碱金属含量为50ppm-100ppm；
基于所述隔膜的总质量，所述第二基团中的氢含量为10ppm-50ppm。
该隔膜用于锂离子电池，锂离子电池表现出显著降低的电池内阻和显著提升的电池容量保持率。
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 (19)

  1. 一种隔膜，其包括微孔层，该微孔层包括含碱金属聚合物，所述含碱金属聚合物包括聚合物链，所述聚合物链含有第一基团和第二基团；
    (a)所述第一基团选自有机酸碱金属基团、醇碱金属基团、或其组合；
    (b)所述第二基团选自有机酸基团；
    基于所述隔膜的总质量，所述第一基团中的碱金属含量为50ppm-100ppm；
    基于所述隔膜的总质量，所述第二基团中的氢含量为10ppm-50ppm。
  2. 根据权利要求1所述的隔膜，所述第一基团的碱金属含量和所述第二基团的氢含量的比为1-10:1，可选为5-10:1。
  3. 根据权利要求1所述的隔膜，所述碱金属聚合物的重均分子量为100-5000。
  4. 根据权利要求1所述的隔膜，所述聚合物链选自聚烯烃链、聚酯链、聚环氧烷基链。
  5. 根据权利要求2所述的隔膜，其具有以下一项或多项特征：
    (1)所述聚烯烃链包括聚苯烯烃链、聚腈烯烃链或其组合；
    (2)所述聚酯链包括聚羧酸酯链；
    (3)所述聚环氧烷基链包括聚烷基乙二醇链。
  6. 根据权利要求1～3任一项所述的隔膜，所述有机酸碱金属基团选自羧酸碱金属基团、磺酸碱金属基团、硝酸碱金属基团、磷酸碱金属基团、硼酸碱金属基团或其组合。
  7. 根据权利要求1～4任一项所述的隔膜，所述有机酸基团选自羧酸基团、磺酸基团、硝酸基团、膦酸基团、硼酸基团或其组合。
  8. 根据权利要求1～4任一项所述的隔膜，一个所述聚合物链包括端基基团和侧链基团，一个或多个所述侧链基团为所述第一基团，一个或多个所述端基基团为所述第二基团。
  9. 根据权利要求1～6任一项所述的隔膜，所述含碱金属聚合物含有交联剂基团，所述交联剂基团占所述含碱金属聚合物总质量的0.1～10％。
  10. 根据权利要求1～7任一项所述的隔膜，所述含碱金属聚合物为自由基聚合物。
  11. 根据权利要求1～8任一项所述的隔膜，所述碱金属选自锂、钠或钾。
  12. 根据权利要求1～9任一项所述的隔膜，所述聚合物链具有以下通式：
    Figure PCTCN2022086860-appb-100001
    其中，R为C 0-10基，-IO lLi为所述第一基团，-IO 1H为所述第二基团。
    其中，x＝1-10，y＝0-10，z＝1-10。
  13. 根据权利要求12所述的隔膜，所述R包括以下一种或多种基团：芳香基团、含氧基团、含氮基团。
  14. 根据权利要求12所述的隔膜，其具有以下一项或多项特征：
    (1)所述R为苯基或取代苯基、酰胺基、或羟基；
    (2)所述-IO lLi为-SO 3Li、-NO 2Li、-PO 3Li或-BO 2Li或-OLi；
    (3)所述-IO 1H为-SO 3H、-NO 2H、-PO 3H或-BO 2H。
  15. 根据权利要求1～14任一项所述的隔膜，所述微孔层包括微孔基体层和修饰膜，所述修饰膜覆盖所述微孔基体层的至少部分表面，所述修饰膜含有所述含碱金属聚合物。
  16. 根据权利要求1～15任一项所述的隔膜，所述修饰膜的厚度为1-100纳米。
  17. 一种用于电池的隔膜的制备方法，包括
    提供微孔基体层；
    在所述微孔基体层的至少部分表面形成修饰膜；
    所述修饰膜含有含碱金属聚合物，所述含碱金属聚合物包括聚合物链，所述聚合物链含有第一基团和第二基团；
    (a)所述第一基团选自有机酸碱金属基团、醇碱金属基团、或其组合；
    (b)所述第二基团选自有机酸基团；
    基于所述隔膜的总质量，所述第一基团中的碱金属含量为50ppm-100ppm；
    基于所述隔膜的总质量，所述第二基团中的氢含量为10ppm-50ppm。
  18. 一种二次电池，包括权利要求1～16任一项所述的隔膜。
  19. 一种装置，包括选自权利要求18所述的二次电池。
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CN101375435A (zh) * 2001-06-08 2009-02-25 永备电池有限公司 电化学电池隔膜
CN103283061A (zh) * 2010-10-28 2013-09-04 日本瑞翁株式会社 二次电池多孔膜、二次电池多孔膜用浆料以及二次电池

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4670146A (en) * 1981-06-24 1987-06-02 Asahi Kasei Kogyo Kabushiki Kaisha Composite hydrophilic membrane and method for manufacture thereof
JP2000268799A (ja) * 1999-03-15 2000-09-29 Mitsubishi Chemicals Corp リチウムイオン二次電池
CN101375435A (zh) * 2001-06-08 2009-02-25 永备电池有限公司 电化学电池隔膜
CN103283061A (zh) * 2010-10-28 2013-09-04 日本瑞翁株式会社 二次电池多孔膜、二次电池多孔膜用浆料以及二次电池

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