WO2022205163A1 - 隔离膜及包含该隔离膜的电化学装置和电子装置 - Google Patents

隔离膜及包含该隔离膜的电化学装置和电子装置 Download PDF

Info

Publication number
WO2022205163A1
WO2022205163A1 PCT/CN2021/084661 CN2021084661W WO2022205163A1 WO 2022205163 A1 WO2022205163 A1 WO 2022205163A1 CN 2021084661 W CN2021084661 W CN 2021084661W WO 2022205163 A1 WO2022205163 A1 WO 2022205163A1
Authority
WO
WIPO (PCT)
Prior art keywords
polymer
coating
separator
coating layer
present application
Prior art date
Application number
PCT/CN2021/084661
Other languages
English (en)
French (fr)
Inventor
熊长川
樊晓贺
魏增斌
Original Assignee
宁德新能源科技有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 宁德新能源科技有限公司 filed Critical 宁德新能源科技有限公司
Priority to EP21933828.2A priority Critical patent/EP4318778A1/en
Priority to KR1020237032047A priority patent/KR20230141893A/ko
Priority to CN202180004688.9A priority patent/CN114175384A/zh
Priority to BR112023019956A priority patent/BR112023019956A2/pt
Priority to PCT/CN2021/084661 priority patent/WO2022205163A1/zh
Priority to JP2023558637A priority patent/JP2024510512A/ja
Publication of WO2022205163A1 publication Critical patent/WO2022205163A1/zh
Priority to US18/478,175 priority patent/US20240030551A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/417—Polyolefins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/42—Acrylic resins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/426—Fluorocarbon polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/431—Inorganic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/44—Fibrous 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
    • H01M50/443—Particulate material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/451—Separators, membranes or diaphragms characterised by the material having a layered structure comprising layers of only organic material and layers containing inorganic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—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
    • H01M50/46—Separators, membranes or diaphragms characterised by their combination with electrodes
    • H01M50/461—Separators, membranes or diaphragms characterised by their combination with electrodes with adhesive layers between electrodes and separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/497—Ionic conductivity
    • 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 technical field of electrochemistry, and in particular, to a separator, an electrochemical device and an electronic device including the separator.
  • Lithium-ion batteries have the characteristics of large specific energy, high operating voltage, low self-discharge rate, small size and light weight, and are widely used in various fields such as electrical energy storage, portable electronic devices and electric vehicles.
  • the purpose of the present application is to provide a separator and an electrochemical device and an electronic device comprising the separator, so as to improve the kinetic performance of a lithium ion battery, especially the cycle performance under low temperature conditions.
  • the specific technical solutions are as follows:
  • the present application is explained by taking a lithium ion battery as an example of an electrochemical device, but the electrochemical device of the present application is not limited to a lithium ion battery.
  • a first aspect of the present application provides a release film, comprising a substrate and a first coating layer disposed on at least one surface of the substrate, wherein the first coating layer includes a first polymer, based on the first coating layer , the mass percentage x of the first polymer is 60% to 90%, and the softening point of the first polymer is 90°C to 150°C.
  • the first coating of the present application is provided on at least one surface of the substrate, for example, the first coating may be provided on one surface of the substrate, or the first coating may be provided on both surfaces of the substrate.
  • the positive electrode in the present application may specifically refer to a positive electrode pole piece, and the negative electrode may specifically refer to a negative electrode pole piece.
  • the mass percentage x of the first polymer is 60% to 90%, preferably 70% to 85%, and the softening point of the first polymer is 90°C to 150°C °C, preferably 135°C to 150°C.
  • the content of the first polymer is too high (for example, higher than 90%)
  • the relative content of the auxiliary binder in the first coating decreases, the cohesion of the first coating is lower, and the first coating of the separator has a lower content.
  • the adhesion between a coating and the positive electrode will decrease with the decrease of the cohesion of the first coating; when the content of the first polymer is too low (for example, less than 60%), the gap brought by the first polymer will decrease , affecting the transport of the electrolyte between the first coating interface and the cycle performance of the lithium-ion battery; when the softening point of the first polymer is too high (for example, higher than 150°C), the first polymer is not easy to soften when heated , the formed bonding area is small, which affects the bonding force between the first coating and the electrode sheet; when the softening point of the first polymer is too low (for example, lower than 90 ° C), the first polymer is easy to soften after Clogging the pores of the first coating or separator, affecting the kinetic performance of Li-ion batteries.
  • softening point refers to the temperature at which a substance softens.
  • a first coating with excellent interfacial bonding performance and moderate gaps between polymer particles can be obtained, which effectively improves the performance of the separator. Bonding properties and electrolyte wettability, thereby improving the kinetic properties of Li-ion batteries, such as low-temperature cycling performance.
  • the first polymer comprises at least one of vinylidene fluoride, hexafluoropropylene, ethylene, propylene, vinyl chloride, propylene chloride, acrylic acid, acrylate, styrene, butadiene, or acrylonitrile A sort of.
  • the thickness of the first coating is 3 ⁇ m to 40 ⁇ m.
  • the thickness of the first coating is too high (for example, higher than 40 ⁇ m)
  • the ion transmission distance will be increased, the kinetic performance of the lithium ion battery will be deteriorated, and the energy density of the battery will not be improved.
  • the thickness is too low (for example, less than 3 ⁇ m)
  • the infiltration of the electrolyte between the coatings will be affected, which is not conducive to the improvement of the kinetic performance of the lithium-ion battery.
  • the number of particles of the first polymer particles having a maximum length between 10 ⁇ m and 30 ⁇ m is between 10 and 30.
  • the separator of the present application is observed under a magnification of 500 times by SEM (Scanning Electron Microscope), in any 250 ⁇ m ⁇ 200 ⁇ m area on the surface of the first coating, the number of particles with the maximum length of the first polymer particles between 10 ⁇ m and 30 ⁇ m Between 10 and 30.
  • SEM Sccanning Electron Microscope
  • the relative content of the first polymer is relatively high, the content of the auxiliary binder is relatively low, the cohesion of the first coating layer is low, and the first coating layer is in the form of large particles.
  • the adhesion performance of the first polymer cannot be reflected due to the low cohesion of the first coating, which will cause the adhesion between the first coating and the positive electrode to decrease.
  • the first polymer particles can present a point-like discrete distribution in the first coating layer, providing channels for electrolyte transmission, and further improving the Li-ion battery performance, especially low temperature performance.
  • the ionic impedance Z of the isolation membrane is 0.5 ⁇ to 1.2 ⁇ .
  • the ionic impedance of the separator is too low (for example, lower than 0.5 ⁇ )
  • the K value of the lithium-ion battery is likely to be too large, resulting in self-discharge
  • the ionic impedance of the separator is too high (for example, higher than 1.2 ⁇ ) ⁇ )
  • the ionic impedance of the separator of the present application By controlling the ionic impedance of the separator of the present application to be within the above range, the ion transport capability of the separator can be improved, the dynamic performance of the lithium ion battery can be improved, and the self-discharge phenomenon of the lithium ion battery can be reduced.
  • K value refers to the voltage drop of a battery per unit time.
  • b represents the first ion impedance coefficient, 1 ⁇ b ⁇ 1.2.
  • the content of the first polymer in the first coating and the ionic impedance of the separator satisfy the above relationship, which can further improve the ion transport capacity of the separator, improve the kinetic performance of the lithium ion battery, and reduce the self-discharge phenomenon of the lithium ion battery .
  • the adhesion force F between the first coating and the positive electrode sheet is 3 N/m to 35 N/m, preferably 15 N/m to 30 N/m.
  • the bonding force between the first coating and the positive electrode is too low (for example, lower than 3N/m)
  • the bonding strength between the interfaces and the structural stability of the lithium ion battery are affected, and the lithium ion
  • the battery is more likely to expand after charge-discharge cycles; when the adhesion between the first coating and the positive electrode is too high (for example, higher than 35N/m), more binders need to be used, which is not conducive to lithium ions
  • the improvement of battery energy density By controlling the adhesive force between the first coating of the present application and the positive electrode sheet within the above range, the structural stability and energy density of the lithium ion battery can be further improved.
  • a represents the cohesion coefficient, 5.0 ⁇ a ⁇ 30.
  • the first coating layer further includes an auxiliary binder, and the mass percentage content of the auxiliary binder is 10% to 40% based on the total mass of the first coating layer.
  • the content of the auxiliary binder in the first coating is too high (eg, above 40%), the content of the first polymer decreases, so that the gap caused by the particulate first polymer decreases , affecting the transport of the electrolyte between the interface of the first coating and the adhesion between the first coating and the electrode sheet; when the content of the auxiliary binder in the first coating is too low (for example, lower than 10%), the cohesion of the first coating is low, and the bonding performance of the first polymer will decrease with the decrease of the cohesion of the first coating.
  • the auxiliary binder can include ethyl acrylate, butyl acrylate, ethyl methacrylate, styrene, chlorostyrene, fluorine At least one of styrene, methylstyrene, acrylic acid, methacrylic acid, maleic acid, acrylonitrile or butadiene.
  • one surface of the substrate includes a first coating and the other surface of the substrate includes a second coating.
  • the thickness of the second coating layer of the present application is 0.2 ⁇ m to 4 ⁇ m.
  • the thickness of the second coating should not be too low or too high.
  • the thickness of the second coating is too low (for example, less than 0.2 ⁇ m)
  • the bonding force between the interfaces will be insufficient, and the bonding performance of the coating will be reduced
  • the thickness is too high (for example, higher than 4 ⁇ m)
  • the transmission distance of lithium ions in the separator is increased, which affects the rate performance of lithium ion batteries.
  • the second coating layer comprises a second polymer
  • the second polymer comprises a core-shell structured high molecular polymer or a non-core-shell structured high molecular polymer, based on the total amount of the second coating layer. mass, the mass percentage of the second polymer is 78% to 87.5%.
  • the core main component of the high molecular polymer of core-shell structure can be a polymer, and the polymer can be a kind of A homopolymer obtained by polymerizing a polymerizable monomer may also be a copolymer obtained by polymerizing two or more types of polymerizable monomers.
  • the core of the high molecular polymer of the core-shell structure includes ethyl acrylate, butyl acrylate, ethyl methacrylate, styrene, chlorostyrene, fluorostyrene, methylstyrene, acrylic acid, methacrylic acid or At least one of maleic acid;
  • the shell of the high molecular polymer of the core-shell structure can also be a homopolymer of a polymerizable monomer, or a copolymer of two or more polymerizable monomers, so Said polymerizable monomers may include acrylates, aromatic monovinyl compounds or nitrified vinyl compounds.
  • the shell of the high molecular polymer of the core-shell structure includes methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene, chlorostyrene, At least one of fluorostyrene, methylstyrene, acrylonitrile or methacrylonitrile.
  • the high molecular polymer of non-core-shell structure includes at least one of acrylic acid, acrylate, butadiene, styrene, acrylonitrile, ethylene, chlorostyrene, fluorostyrene or propylene.
  • thickeners, auxiliary binders and wetting agents may also be included in the second coating.
  • the function of the thickener is to increase the stability of the slurry and prevent the slurry from settling.
  • the thickener in the present application can be sodium carboxymethyl cellulose.
  • the auxiliary binder plays the role of auxiliary bonding to further improve the bonding performance of the second coating.
  • the application does not have any special restrictions on the auxiliary binder, as long as the purpose of the application can be achieved, for example, the auxiliary binder Homogeneity that may include ethyl acrylate, butyl acrylate, ethyl methacrylate, styrene, chlorostyrene, fluorostyrene, methylstyrene, acrylic acid, methacrylic acid, maleic acid, acrylonitrile or butadiene at least one of a polymer or a copolymer.
  • the role of the wetting agent is to reduce the surface energy of the slurry and prevent coating leakage. There is no special restriction on the wetting agent as long as it can achieve the purpose of the application.
  • the wetting agent may include dimethylsiloxane. , polyethylene oxide, at least one of oxyethylene alkyl phenol ether, polyoxyethylene fatty alcohol ether, polyoxyethylene polyoxypropylene block copolymer or dioctyl sodium sulfosuccinate.
  • the mass percentage content of the second polymer is 78% to 87.5%, and the mass percentage content of the auxiliary binder is 5% to 10% , the mass percentage content of the thickener is 0.5% to 2%, and the mass percentage content of the wetting agent is 7% to 10%, so that the second coating layer with excellent bonding performance can be obtained.
  • an inorganic coating is further provided between the first coating and the substrate and/or between the second coating and the substrate, and the thickness of the inorganic coating is 0.5 ⁇ m to 6 ⁇ m. .
  • an inorganic coating is provided between the first coating and the substrate; or, an inorganic coating is provided between the second coating and the substrate; or, the first coating and the substrate are Inorganic coatings are arranged between the materials and between the second coating and the base material, and the above-mentioned setting methods can further improve the strength of the isolation film.
  • the thickness of the inorganic coating when the thickness of the inorganic coating is too low (for example, less than 0.5 ⁇ m), the strength of the separator decreases, which is not conducive to the improvement of the cycle performance of lithium-ion batteries; when the thickness of the inorganic coating is too high (for example, high than 6 ⁇ m), the overall thickness of the isolation film is not conducive to the improvement of the energy density of lithium-ion batteries.
  • the thickness of the inorganic coating is too low (for example, less than 0.5 ⁇ m), the strength of the separator decreases, which is not conducive to the improvement of the cycle performance of lithium-ion batteries; when the thickness of the inorganic coating is too high (for example, high than 6 ⁇ m), the overall thickness of the isolation film is not conducive to the improvement of the energy density of lithium-ion batteries.
  • inorganic particles are included in the inorganic coating, and the Dv50 of the inorganic particles is 0.1 ⁇ m to 3 ⁇ m.
  • the particle size of the inorganic particles should not be too large or too small.
  • the particle size of the inorganic particles is too large (for example, larger than 3 ⁇ m)
  • the particle size is too small (for example, less than 0.1 ⁇ m)
  • the pores of inorganic particles are reduced, which affects the ion transport and thus the kinetic performance of the lithium-ion battery.
  • Inorganic particles include boehmite, magnesium hydroxide, aluminum oxide, titanium dioxide, silicon dioxide, zirconium dioxide, tin dioxide, magnesium oxide, oxide At least one of zinc, barium sulfate, boron nitride, aluminum nitride, or silicon nitride.
  • the inorganic particles may be boehmite with a Dv50 of 0.1 ⁇ m to 3 ⁇ m and an aspect ratio of 1 to 3.
  • the strength of the inorganic coating layer can be further improved, thereby improving the performance of the separator.
  • the side of the separator provided with the first coating can be in contact with the positive electrode piece, and the side of the separator with the second coating can be brought into contact with the negative electrode piece, so that the space between the separator and the positive electrode piece and the negative electrode piece can be Both have good bonding effect, and have better electrolyte wettability between the separator and the positive electrode, thereby improving the low-temperature cycle performance and fast-charging cycle performance of the lithium-ion battery.
  • the separator of the present application has lithium ion permeability and electron barrier properties.
  • the first polymer is secondary particles, and the secondary particles have an average particle diameter D50 of 10 ⁇ m to 30 ⁇ m.
  • the secondary particles can be formed by the aggregation of the primary particles of the first polymer, for example, the secondary particles formed by the aggregation of the primary particles of PVDF, so that the interior of the secondary particles has more voids, and the electrolyte is more likely to penetrate into these voids, thereby It is beneficial to improve the electrolyte wettability of the separator.
  • the preparation method of the first polymer of the present application is not particularly limited, and the preparation method of those skilled in the art can be adopted, for example, the following preparation method can be adopted:
  • the reaction kettle was evacuated, and nitrogen was evacuated to replace oxygen. Then, deionized water, vinylidene fluoride (VDF), emulsifier perfluoroalkyl carboxylate, and chain transfer agent isopropanol were added to the reaction kettle containing the stirrer until the reaction was carried out.
  • the pressure of the kettle is about 3.5MPa. Then the temperature was raised to 50°C to 70°C, the stirring speed was 70r/min to 100r/min, and the polymerization reaction was started. At the same time, the vinylidene fluoride monomer was continuously added to maintain the pressure of the reactor at 3.5MPa, until the solid content of the emulsion in the reactor reached 25%. The reaction is stopped at 30%, the unreacted monomer is recovered, the polymer emulsion is released, and after centrifugation, washing and drying, the first polymer particles are obtained.
  • the initiator in the present application, as long as it can initiate the polymerization of the monomer, for example, it can be dicumyl hydroperoxide.
  • the amount of monomers, deionized water, initiators, and chain transfer agents added in this application as long as the added monomers can be polymerized.
  • deionized water is 5 to 10 times the mass of the monomers.
  • the initiator accounts for 0.05% to 0.5% of the mass of the monomer
  • the emulsifier accounts for 0.1% to 1% of the mass of the monomer
  • the chain transfer agent accounts for 3% to 7% of the mass of the monomer.
  • a positive electrode sheet in the present application is not particularly limited, as long as the purpose of the present application can be achieved.
  • a positive electrode sheet typically includes a positive electrode current collector and a positive electrode active material layer.
  • the positive electrode current collector may be aluminum foil, aluminum alloy foil, or composite current collector, or the like.
  • the positive electrode active material layer includes a positive electrode active material and a conductive agent, and the positive electrode active material can include nickel cobalt lithium manganate (811, 622, 523, 111), nickel cobalt lithium aluminate, lithium iron phosphate, lithium-rich manganese-based material, cobalt acid At least one of lithium, lithium manganate, lithium iron manganese phosphate or lithium titanate.
  • the conductive agent may include at least one of conductive carbon black (Super P), carbon nanotubes (CNTs), carbon nanofibers, flake graphite, acetylene black, carbon black, Ketjen black, carbon dots, graphene, and the like.
  • a negative electrode sheet typically includes a negative electrode current collector and a negative electrode active material layer.
  • the negative electrode current collector can be copper foil, aluminum foil, aluminum alloy foil, composite current collector, and the like.
  • the negative electrode active material layer includes a negative electrode active material, and the negative electrode active material may include at least one of artificial graphite, natural graphite, mesocarbon microspheres, soft carbon, hard carbon, silicon, silicon carbon, lithium titanate, and the like.
  • the substrate of the present application includes, but is not limited to, at least one of polyethylene, polypropylene, polyethylene terephthalate, polyimide, or aramid.
  • the polyethylene includes at least one component selected from the group consisting of high density polyethylene, low density polyethylene, and ultra-high molecular weight polyethylene.
  • polyethylene and polypropylene they have a good effect on preventing short circuits and can improve the stability of lithium-ion batteries through the shutdown effect.
  • the lithium ion battery of the present application further includes an electrolyte, and the electrolyte may be one or more of a gel electrolyte, a solid electrolyte, and an electrolyte, and the electrolyte includes a lithium salt and a non-aqueous solvent.
  • the lithium salt is selected from LiPF 6 , LiBF 4 , LiAsF 6 , LiClO 4 , LiB(C 6 H 5 ) 4 , LiCH 3 SO 3 , LiCF 3 SO 3 , LiN(SO 2 CF 3 ) 2.
  • LiC(SO 2 CF 3 ) 3 LiSiF 6 , LiBOB and lithium difluoroborate.
  • LiPF 6 can be chosen as the lithium salt because it can give high ionic conductivity and improve cycle characteristics.
  • the non-aqueous solvent may be a carbonate compound, a carboxylate compound, an ether compound, other organic solvents, or a combination thereof.
  • the above-mentioned carbonate compound may be a chain carbonate compound, a cyclic carbonate compound, a fluorocarbonate compound, or a combination thereof.
  • Examples of the above-mentioned chain carbonate compound are dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), carbonic acid Methyl ethyl ester (MEC) and combinations thereof.
  • Examples of cyclic carbonate compounds are ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylethylene carbonate (VEC), and combinations thereof.
  • fluorocarbonate compounds are fluoroethylene carbonate (FEC), 1,2-difluoroethylene carbonate, 1,1-difluoroethylene carbonate, 1,1,2-trifluoroethylene carbonate Ethyl carbonate, 1,1,2,2-tetrafluoroethylene carbonate, 1-fluoro-2-methylethylene carbonate, 1-fluoro-1-methylethylene carbonate, 1,2-dicarbonate Fluoro-1-methylethylene, 1,1,2-trifluoro-2-methylethylene carbonate, trifluoromethylethylene carbonate, and combinations thereof.
  • FEC fluoroethylene carbonate
  • 1,2-difluoroethylene carbonate 1,1-difluoroethylene carbonate
  • 1,1,2-trifluoroethylene carbonate Ethyl carbonate 1,1,2,2-tetrafluoroethylene carbonate
  • 1-fluoro-2-methylethylene carbonate 1-fluoro-1-methylethylene carbonate
  • 1,2-dicarbonate Fluoro-1-methylethylene 1,1,2-trifluoro-2-methylethylene carbonate, trifluoromethyl
  • carboxylate compounds are methyl formate, methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, ⁇ -butyrolactone , caprolactone, valerolactone, mevalonolactone, caprolactone, and combinations thereof.
  • ether compounds examples include dibutyl ether, tetraglyme, diglyme, 1,2-dimethoxyethane, 1,2-diethoxyethane, ethoxymethyl ether Oxyethane, 2-methyltetrahydrofuran, tetrahydrofuran, and combinations thereof.
  • Examples of the above-mentioned other organic solvents are dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone, Formamide, dimethylformamide, acetonitrile, trimethyl phosphate, triethyl phosphate, trioctyl phosphate, phosphate esters, and combinations thereof.
  • a second aspect of the present application provides an electrochemical device, comprising a positive pole piece, a negative pole piece, a separator, and an electrolyte, wherein the separator is located between the positive pole piece and the negative pole piece, and the separator It is the separator described in any of the above embodiments, and has good low temperature cycle performance.
  • a third aspect of the present application provides an electronic device comprising the electrochemical device described in the embodiments of the present application, which has good low-temperature cycle performance.
  • electronic devices may include, but are not limited to, notebook computers, pen input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, headsets, VCRs, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, assisted bicycles, bicycles, Lighting equipment, toys, game consoles, clocks, power tools, flashlights, cameras, large-scale household storage batteries and lithium-ion capacitors, etc.
  • a lithium-ion battery can be manufactured by the following process: the positive electrode and the negative electrode are overlapped through a separator, and they are rolled, folded, etc., and placed into the case as required, and the electrolyte is injected into the case and sealed.
  • an overcurrent preventing element, a guide plate, etc. can also be placed in the case as required, so as to prevent pressure rise and overcharge and discharge inside the lithium ion battery.
  • Dv50 refers to the particle size at which the cumulative distribution of particles is 50%, that is, the volume content of particles smaller than this particle size accounts for 50% of all particles.
  • the present application provides a separator and an electrochemical device and an electronic device including the separator, wherein the separator comprises a substrate and a first coating provided on at least one surface of the substrate, and the first coating comprises a A polymer, in the present application, by controlling the content of the first polymer in the first coating and the softening point at the same time within the above-mentioned ranges, a first coating with excellent interfacial bonding properties and moderate gaps between polymer particles can be obtained, It can effectively improve the bonding performance and electrolyte wettability of the separator, thereby improving the kinetic performance of lithium-ion batteries, such as low-temperature cycling performance.
  • Fig. 1 is the structural schematic diagram of the isolation membrane of the first embodiment of the application
  • FIG. 2 is a schematic structural diagram of the isolation film of the second embodiment of the application.
  • FIG. 3 is a schematic structural diagram of the isolation film of the third embodiment of the present application.
  • FIG. 4 is a schematic structural diagram of the isolation film of the fourth embodiment of the present application.
  • FIG. 5 is a schematic structural diagram of the isolation film according to the fifth embodiment of the present application.
  • the separator of the present application includes a substrate 1 and a first coating layer 2 disposed on one surface of the substrate 1 .
  • the isolation film of the present application includes a substrate 1 , and a first coating layer 2 and a second coating layer 3 respectively provided on two surfaces of the substrate 1 .
  • an inorganic coating layer 4 is disposed between the first coating layer 2 and the substrate 1 .
  • an inorganic coating layer 4 is disposed between the substrate 1 and the second coating layer 3 .
  • an inorganic coating layer 4 is arranged between the substrate 1 and the first coating layer 2 , and an inorganic coating layer is also arranged between the substrate 1 and the second coating layer 3 .
  • Layer 4 is arranged between the substrate 1 and the first coating layer 2 , and an inorganic coating layer is also arranged between the substrate 1 and the second coating layer 3 .
  • the national standard GB/T 2790-1995 is adopted, that is, the 180° peel test standard is used to test the adhesion between the first coating of the separator and the positive pole piece, and the separator with the first coating and the positive pole piece are set Cut into 54.2mm ⁇ 72.5mm samples, compound the side of the separator with the first coating with the positive pole piece, and use a hot press to hot press.
  • the hot pressing conditions are: temperature 85 ° C, pressure 1 Mpa, hot pressing time 85s ( seconds), cut the composited sample into 15mm ⁇ 54.2mm strips, and test the adhesion between the first coating layer of the separator and the positive pole piece according to the 180° peel test standard.
  • Substrate thickness test In the normal temperature environment, take the substrate, cut into 50mm wide splines along the TD direction, three parallel samples, use a micrometer thickness gauge (Mitutoyo Litematic VL-50B, the diameter of the test head is 5mm, Test under pressure 0.01N) uniformly test 10 data points along the central position of the TD direction, after testing 3 parallel samples, take the average value d1 of the 30 test data as the thickness of the substrate;
  • the first coating layer is coated on the above-mentioned substrate, and dried at 80° C. to obtain the isolation film coated with the first coating layer; test according to the substrate thickness test method, test When , the uncoated side faces down; the total thickness d2 of the isolation film is obtained;
  • step 6) cycle the above steps 4) to 5), test each temperature condition in turn according to the temperature conditions in step 4), record the final discharge capacity of the lithium ion battery under each temperature condition in turn, and then select -20 °C condition.
  • the final discharge capacity of the lithium-ion battery was recorded, and the low-temperature capacity retention of the lithium-ion battery at -20°C was calculated using the following expression:
  • Low temperature capacity retention rate (final discharge capacity of lithium-ion battery at -20°C/discharge capacity of lithium-ion battery at the first cycle at 25°C) ⁇ 100%.
  • a general-purpose differential scanning calorimeter (DSC) method was used: 5 mg of the first polymer samples prepared in each example and the comparative example were taken, and the temperature was raised to 150 °C at a heating rate of 5 °C/min, and the DSC curve was collected. The DSC curve determines the softening point, ie the softening temperature, of the first polymer.
  • the separator coated with the first coating was cut into a 10mm ⁇ 10mm sample, and then the sample was placed under the SEM to observe at a magnification of 500 times, and any five 250 ⁇ m ⁇ 200 ⁇ m areas were selected in the field of view, and the selected areas were recorded.
  • the separator and the electrodes are combined into a symmetrical battery: the number of layers of the separator in the symmetrical battery is superimposed by gradient design, and the number of layers is set as follows: 2, 4, 6, 8, 10, and 12 layers of Each electrode pole piece is a negative pole piece that has not undergone a charge-discharge cycle (ie, a fresh negative electrode).
  • the chemistry workstation EIS was used to test the separator impedance values of the above-mentioned symmetrical batteries with different layers of separator designs. Then, the measured ionic impedance values of the symmetrical batteries with different layer numbers of separators were used to measure the gradient data values. Fit, and then calculate the ionic impedance of the single-layer isolation film according to the fitting result, the unit is ⁇ .
  • the formed lithium-ion battery was charged to 4.45V at a constant current rate of 0.2C, and then charged at a constant voltage until the current was less than or equal to 0.05C. V, the test obtains the 0.2C rate discharge capacity of the lithium-ion battery.
  • Lithium ion secondary battery 1.5C rate discharge capacity retention rate (%) 1.5C rate discharge capacity/0.2C rate discharge capacity ⁇ 100%.
  • the reaction kettle was evacuated, and after nitrogen was used to replace oxygen, deionized water, vinylidene fluoride (VDF), initiator dicumyl hydroperoxide, and emulsifier perfluoroalkyl carboxylic acid were added to the reaction kettle containing the stirrer.
  • the pressure of salt and chain transfer agent isopropanol to the reactor is 3.5MPa, in which deionized water is 7 times the mass of vinylidene fluoride monomer, the initiator accounts for 0.2% of the mass of vinylidene fluoride monomer, and the emulsifier accounts for vinylidene fluoride monomer.
  • the chain transfer agent accounts for 5% of the mass of the vinylidene fluoride monomer. Then the temperature was raised to 60°C, the speed of the stirrer was 80r/min, and the polymerization reaction was started. At the same time, the vinylidene fluoride monomer was continuously added to maintain the pressure of the reactor at 3.5MPa, and the reaction was stopped until the solid content of the emulsion in the reactor reached 25%, and the unreacted monomer was recovered. After the polymer emulsion is released, the first polymer particles are obtained after centrifugation, washing and drying. The softening point of the first polymer particles was 120° C. and the Dv50 was 20 ⁇ m.
  • the positive active material lithium cobaltate, acetylene black, and polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 94:3:3, and then N-methylpyrrolidone (NMP) was added as a solvent to prepare a slurry with a solid content of 75%. ingredients and mix well.
  • the slurry was uniformly coated on one surface of an aluminum foil with a thickness of 12 ⁇ m, dried at 90° C., and after cold pressing, a positive electrode sheet with a thickness of 100 ⁇ m of positive active material layer was obtained, and then on the other surface of the positive electrode sheet.
  • the above steps are repeated to obtain a positive electrode sheet coated with a positive electrode active material layer on both sides. Cut the positive pole piece into a size of 74mm ⁇ 867mm and weld the tabs for later use.
  • the negative active material artificial graphite, acetylene black, styrene-butadiene rubber and sodium carboxymethyl cellulose are mixed in a mass ratio of 96:1:1.5:1.5, and then deionized water is added as a solvent to prepare a slurry with a solid content of 70% , and stir well.
  • the slurry was evenly coated on one surface of a copper foil with a thickness of 8 ⁇ m, dried at 110° C., and after cold pressing, a negative electrode pole piece with a negative electrode active material layer thickness of 150 ⁇ m was obtained on one side coated with a negative electrode active material layer, Then, the above coating steps are repeated on the other surface of the negative electrode pole piece to obtain a negative electrode pole piece coated with a negative electrode active material layer on both sides. Cut the negative pole piece into a size of 74mm ⁇ 867mm and weld the tabs for use.
  • the prepared first polymer particles and the auxiliary binder acrylonitrile were added to the mixer according to the mass ratio of 90:10, stirred and mixed evenly, and then deionized water was added for stirring to adjust the slurry viscosity to 100 mPa ⁇ s, and the solid content was 12% to obtain slurry A; uniformly coat slurry A on one side of a PE substrate with a thickness of 5 ⁇ m to obtain a first coating layer with a thickness of 20 ⁇ m, and finish drying in an oven to obtain a separator.
  • the prepared separator was observed under 500 times magnification by SEM, in any 250 ⁇ m ⁇ 200 ⁇ m area (within unit area) on the surface of the first coating, the maximum length of the first polymer particles was between 10 ⁇ m and 30 ⁇ m. The number of particles is 30.
  • the non-aqueous organic solvent In an environment with a water content of less than 10 ppm, the non-aqueous organic solvents ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), propyl propionate (PP), vinylene carbonate ( VC) mix according to mass ratio 20:30:20:28:2, then in non-aqueous organic solvent, add lithium hexafluorophosphate (LiPF 6 ) to dissolve and mix uniformly, obtain electrolyte, wherein, LiPF 6 and the mass ratio of non-aqueous organic solvent 8:92.
  • LiPF 6 lithium hexafluorophosphate
  • the above-prepared positive pole piece, separator, and negative pole piece are stacked in sequence, the side of the separator with the first coating is contacted with the positive pole piece, and an electrode assembly is obtained by winding.
  • the electrode assembly is put into an aluminum-plastic film packaging bag, and the moisture is removed at 80 ° C, the prepared electrolyte is injected, and the lithium ion battery is obtained through vacuum packaging, standing, forming, and shaping.
  • the mass ratio of the first polymer particles to the auxiliary binder is 85:15 (ie, the percentage of the first polymer is 85%), the rest is the same as that of Example 1.
  • the mass ratio of the first polymer particles to the auxiliary binder is 80:20 (ie, the percentage of the first polymer is 80%), the rest is the same as that of Example 1.
  • the mass ratio of the first polymer particles to the auxiliary binder is 75:25 (ie, the percentage of the first polymer is 75%), the rest is the same as that of Example 1.
  • the mass ratio of the first polymer particles to the auxiliary binder is 70:30 (that is, the percentage content of the first polymer is 70%), the rest is the same as that of Example 1.
  • the mass ratio of the first polymer particles to the auxiliary binder is 65:35 (ie, the percentage of the first polymer is 65%), the rest is the same as that of Example 1.
  • the mass ratio of the first polymer particles to the auxiliary binder is 60:40 (ie, the percentage of the first polymer is 60%), the rest is the same as that of Example 1.
  • Example 4 The same procedure as in Example 4 was performed except that the softening point of the first polymer was adjusted to 90° C. in ⁇ Preparation of First Polymer Particles>.
  • Example 4 The same procedure as in Example 4 was performed except that the softening point of the first polymer was adjusted to 100° C. in ⁇ Preparation of First Polymer Particles>.
  • Example 4 The same procedure as in Example 4 was performed except that the softening point of the first polymer was adjusted to 110° C. in ⁇ Preparation of First Polymer Particles>.
  • Example 4 The same procedure as in Example 4 was performed except that the softening point of the first polymer was adjusted to 130° C. in ⁇ Preparation of First Polymer Particles>.
  • Example 4 The same procedure as in Example 4 was performed except that the softening point of the first polymer was adjusted to 140° C. in ⁇ Preparation of First Polymer Particles>.
  • Example 4 The same procedure as in Example 4 was performed except that the softening point of the first polymer was adjusted to 150° C. in ⁇ Preparation of First Polymer Particles>.
  • Example 4 is the same as Example 4, except that the polyvinylidene fluoride particles of the first coating layer are replaced by a copolymer formed by mass fraction of 75% vinylidene fluoride and 25% hexafluoropropylene.
  • Example 4 Except that in Example 4, the polyvinylidene fluoride particles of the first coating layer are replaced by a copolymer formed by mass fraction of 60% styrene, 25% butadiene, and 15% acrylic acid, the rest is the same as that in Example 4.
  • Example 4 Except that in Example 4, the polyvinylidene fluoride particles of the first coating layer are replaced with a copolymer formed by mass fraction of 70% styrene and 30% acrylate, the rest is the same as that of Example 4.
  • Example 4 is the same as Example 4, except that the polyvinylidene fluoride particles of the first coating layer are replaced by a copolymer formed by mass fraction of 30% acrylic acid, 35% acrylonitrile, and 35% styrene.
  • the thickness of the first coating layer was 3 ⁇ m.
  • the thickness of the first coating layer was 5 ⁇ m.
  • the thickness of the first coating layer was 8 ⁇ m.
  • the thickness of the first coating layer was 50 ⁇ m.
  • the thickness of the first coating layer was 10 ⁇ m.
  • the thickness of the first coating layer was 40 ⁇ m.
  • Example 4 The rest is the same as Example 4 except that the second coating layer is added in ⁇ Preparation of Separator Film>, and ⁇ Preparation of Lithium Ion Battery> is different from Example 4.
  • Non-core-shell structure polymer binder (copolymer made by mass fraction of 80% styrene, 10% isobutyl acrylate and 10% acrylonitrile, Dv50 is 0.3 ⁇ m), thickener Sodium carboxymethyl cellulose and wetting agent dimethyl siloxane were added to the mixer according to the mass ratio of 85:14:1, stirred and mixed evenly, then deionized water was added for stirring, and the viscosity of the slurry was adjusted to 40mPa ⁇ s. The solid content was 5%, and slurry B was obtained. The above slurry B was uniformly coated on the other side of the PE substrate to obtain a second coating layer with a thickness of 2 ⁇ m, which was dried in an oven.
  • the above-prepared positive pole piece, separator, and negative pole piece are stacked in order, the side of the separator with the first coating is in contact with the positive pole piece, and the side of the separator with the second coating is in contact with the negative pole piece , and rolled to obtain an electrode assembly.
  • the electrode assembly is put into an aluminum-plastic film packaging bag, and the moisture is removed at 80 ° C, the prepared electrolyte is injected, and the lithium ion battery is obtained through vacuum packaging, standing, forming, and shaping.
  • Example 24 The same as in Example 24, except that in ⁇ Preparation of Separator Film>, the thickness of the second coating layer was adjusted to 0.2 ⁇ m.
  • Example 24 The same as in Example 24 except that in ⁇ Preparation of Separator Film>, the thickness of the second coating layer was adjusted to 4 ⁇ m.
  • Example 24 The same as in Example 24, except that an inorganic coating layer was provided between the first coating layer and the substrate as shown in FIG. 3 in ⁇ Preparation of Separator Film>.
  • the thickness of the inorganic coating is 3 ⁇ m
  • the inorganic particles in the inorganic coating are boehmite
  • the Dv50 is 0.75 ⁇ m
  • the aspect ratio is 1.
  • Example 27 The same procedure as in Example 27 was performed except that in ⁇ Preparation of Separator Film>, the thickness of the inorganic coating layer was adjusted to 0.5 ⁇ m and the Dv50 of the boehmite was 0.85 ⁇ m.
  • Example 27 The procedure was the same as Example 27, except that in ⁇ Preparation of Separator Film>, the thickness of the inorganic coating layer was adjusted to 6 ⁇ m and the Dv50 was adjusted to 0.99 ⁇ m.
  • an inorganic coating is arranged between the second coating and the substrate, and the inorganic particles in the inorganic coating are alumina with a Dv50 of 0.99 ⁇ m, the rest are the same as the implementation.
  • Example 24 is the same.
  • the inorganic coating thickness is 3 ⁇ m.
  • an inorganic coating is arranged between the first coating and the substrate and between the second coating and the substrate, and the inorganic particles in the inorganic coating are selected. It is the same as Example 24 except that Dv50 is 0.99 micrometer alumina. The thickness of the inorganic coating layer is 2 ⁇ m.
  • Disperse the primary particles of the first polymer into deionized water use an MSK-SFM-10 vacuum stirrer, and stir for 120 minutes at a revolution speed of 40 rpm and a rotation speed of 1500 rpm for 120 minutes to obtain a primary particle slurry with a solid content of 10%;
  • the primary particle slurry is transferred to the centrifugal turntable nozzle of the spray drying granulator, and the centrifugal speed is 2000 rpm to form tiny mist droplets.
  • the inlet temperature of the spray drying granulator is 110°C, and the outlet temperature is 100°C, and the powder is collected by cooling to obtain PVDF secondary particles.
  • the mass ratio of the first polymer particles to the auxiliary binder is 95:5 (ie, the percentage content of the first polymer is 95%), the rest is the same as that of Example 1.
  • the mass ratio of the first polymer particles to the auxiliary binder is 55:45 (ie, the percentage of the first polymer is 55%), the rest is the same as that of Example 1.
  • Example 2 The same procedure as in Example 1 was performed except that the softening point of the first polymer was adjusted to 165° C. in ⁇ Preparation of First Polymer Particles>.
  • Example 2 The same procedure as in Example 1 was performed except that the softening point of the first polymer was adjusted to 70° C. in ⁇ Preparation of First Polymer Particles>.
  • the content of the first polymer when the content of the first polymer is too high (for example, Comparative Example 1), it affects the adhesion between the first coating and the positive electrode; when the content of the first polymer is too low (for example, Comparative Example 2), it affects the lithium ion
  • the low-temperature capacity retention rate of the battery from Examples 4, 8 to 13 and Comparative Examples 3 to 4, it can be seen that with the increase of the softening point of the first polymer, the adhesion force F between the first coating and the positive electrode plate increases. In a downward trend, the low-temperature capacity retention rate of lithium-ion batteries generally shows an upward trend.
  • Example 27 and Comparative Example 5 it can be seen from Example 27 and Comparative Example 5 that by controlling the content and softening point of the first polymer while being within the scope of the present application, the interfacial bonding performance of the first coating and the low temperature cycle performance of the lithium ion battery can be improved.
  • the composition of the first polymer also generally affects the performance of the first coating.
  • the first coating containing the first polymer composition of the present application can enable lithium-ion batteries to have excellent low temperature cycling. performance and rate capability.
  • the thickness of the second coating layer, the thickness of the inorganic coating layer, the composition and particle size of the inorganic particles, and the arrangement of the second coating layer and the inorganic coating layer in the separator generally also affect the performance of the separator, thus affecting the performance of the lithium ion battery. impact on the dynamic performance. It can be seen from Examples 24 to 31 that as long as the thickness of the second coating layer and the thickness of the inorganic coating layer are within the scope of the present application, lithium ion batteries with excellent low-temperature cycle performance can be obtained.
  • the separator containing the first polymer secondary particles has a lower ionic impedance, which may be due to the more voids inside the secondary particles, which makes it easier for the electrolyte to penetrate Into these voids, the electrolyte wettability of the separator of the present application is improved.

Abstract

本申请提供了一种隔离膜及包含该隔离膜的电化学装置和电子装置，其中隔离膜包括基材和设置于基材的至少一个表面上的第一涂层，第一涂层中包含第一聚合物，基于第一涂层的总质量，第一聚合物的质量百分含量x为60％至90％，第一聚合物的软化点为90℃至150℃。本申请的隔离膜具有优异的界面粘结强度，提高了锂离子电池的动力学性能，尤其是低温条件下的循环性能。

Description

隔离膜及包含该隔离膜的电化学装置和电子装置 技术领域
本申请涉及电化学技术领域，具体涉及一种隔离膜及包含该隔离膜的电化学装置和电子装置。
背景技术
锂离子电池具有比能量大、工作电压高、自放电率低、体积小、重量轻等特点，广泛应用于电能储存、便携式电子设备和电动汽车等各个领域。
随着锂离子电池在消费终端等领域应用的迅速发展，人们对锂离子电池的充放电循环性能也有了越高的要求。尤其是在低温条件下，锂离子电池的实际充放电性能远小于设计值，制约了锂离子电池的进一步应用。
发明内容
本申请的目的在于提供一种隔离膜及包含该隔离膜的电化学装置和电子装置，以提高锂离子电池的动力学性能，尤其是在低温条件下的循环性能。具体技术方案如下：
需要说明的是，本申请的内容中，以锂离子电池作为电化学装置的例子来解释本申请，但是本申请的电化学装置并不仅限于锂离子电池。
本申请的第一方面提供了一种隔离膜，包括基材和设置于基材的至少一个表面上的第一涂层，其中，第一涂层中包括第一聚合物，基于第一涂层的总质量，第一聚合物的质量百分含量x为60％至90％，第一聚合物的软化点为90℃至150℃。
本申请的第一涂层设置在基材的至少一个表面，例如，第一涂层可以设置在基材的一个表面上，或者第一涂层可以设置在基材的两个表面上。本申请的正极具体可以指正极极片，负极具体可以指负极极片。
本申请中，基于第一涂层的总质量，第一聚合物的质量百分含量x为60％至90％，优选为70％至85％，第一聚合物的软化点为90℃至150℃，优选为135℃至150℃。不限于任何理论，当第一聚合物的含量过高时(例如高于90％)，第一涂层中的辅助粘结剂相对含量减小，第一涂层内聚力较低，隔离膜的第一涂层与正极之间的粘结力会随第一涂层内聚力的降低而下降；当第一聚合物的含量过低时(例如低于60％)，第一聚合物带来的间隙减少，影响电解液在第一涂层界面间的传输，影响锂离子电池的循环性能；当第一聚合物的软化点过高时(例如高于150℃)，第一聚合物在加热时不易软化，形成的粘结面积较 小，影响第一涂层与电极极片间的粘结力；当第一聚合物的软化点过低时(例如低于90℃)，第一聚合物易软化后堵塞第一涂层或隔离膜孔隙，影响锂离子电池的动力学性能。术语“软化点”表示物质软化的温度。本申请通过控制第一聚合物在第一涂层中的含量和软化点同时在上述范围内，能够得到界面粘结性能优异、聚合物颗粒间间隙适中的第一涂层，有效提升隔离膜的粘结性能和电解液浸润性，从而提高锂离子电池的动力学性能，例如低温循环性能。
在本申请的一种实施方案中，第一聚合物包括偏氟乙烯、六氟丙烯、乙烯、丙烯、氯乙烯、氯丙烯、丙烯酸、丙烯酸酯、苯乙烯、丁二烯或丙烯腈中的至少一种。
在本申请的一种实施方案中，第一涂层的厚度为3μm至40μm。不限于任何理论，当第一涂层的厚度过高时(例如高于40μm)，加大离子传输距离，恶化锂离子电池动力学性能，同时不利于电池能量密度提升；当第一涂层的厚度过低时(例如低于3μm)，影响电解液在涂层间的浸润，不利于锂离子电池动力学性能提升。通过控制本申请第一涂层的厚度在上述范围内，能够进一步提高锂离子电池的动力学性能及电池能量密度。
在本申请的一种实施方案中，在第一涂层表面的任意250μm×200μm区域内，第一聚合物颗粒最大长度处于10μm至30μm之间的颗粒数量在10个至30个。
本申请的隔离膜采用SEM(扫描电子显微镜)在500倍的放大倍数下观察，第一涂层表面的任意250μm×200μm区域内，第一聚合物颗粒最大长度处于10μm至30μm之间的颗粒数量在10个至30个。不限于任何理论，一方面，通过控制第一聚合物颗粒的最大长度处于10μm至30μm之间，能够避免因颗粒粒径过小导致的团聚，从而提高第一聚合物颗粒的分散性，还能避免因颗粒粒径过大导致涂层偏厚，影响锂离子电池能量密度。但最大长度处于10μm至30μm之间的颗粒数量过多时(例如大于30个)，第一聚合物相对含量较高，辅助粘结剂含量较低，第一涂层内聚力较低，呈大颗粒状的第一聚合物的粘结性能由于第一涂层内聚力低而无法体现，会造成第一涂层与正极之间的粘结力下降。通过控制第一聚合物颗粒最大长度处于10μm至30μm之间的颗粒数量在上述范围内，第一聚合物颗粒能够在第一涂层中呈现点状离散分布，为电解液传输提供通道，进一步提升锂离子电池的性能，尤其是低温性能。
在本申请的一种实施方案中，隔离膜的离子阻抗Z为0.5Ω至1.2Ω。不限于任何理论，当隔离膜的离子阻抗过低时(例如低于0.5Ω)，易导致锂离子电池K值过大，产生自放电；当隔离膜的离子阻抗过高时(例如高于1.2Ω)，影响隔离膜的离子传输能力，恶化锂离子 电池动力学性能。通过控制本申请隔离膜的离子阻抗在上述范围内，能够提高隔离膜的离子传输能力，同时提高锂离子电池的动力学性能，降低锂离子电池的自放电现象。术语“K值”指单位时间内的电池的电压降。
在本申请的一种实施方案中，第一聚合物的质量百分含量x与隔离膜的离子阻抗Z之间满足：Z＝x·b。其中，b表示第一离子阻抗系数，1≤b≤1.2。第一聚合物在第一涂层中的含量与隔离膜的离子阻抗满足上述关系式，能够进一步提高隔离膜的离子传输能力、提高锂离子电池的动力学性能、降低锂离子电池的自放电现象。
在本申请的一种实施方案中，第一涂层与正极极片之间的粘结力F为3N/m至35N/m，优选为15N/m至30N/m。不限于任何理论，当第一涂层与正极极片之间的粘结力过低时(例如低于3N/m)，影响界面间的粘结强度及锂离子电池结构稳定性，使锂离子电池在充放电循环后更容易膨胀；当第一涂层与正极极片之间的粘结力过高时(例如高于35N/m)，需使用更多的粘结剂，不利于锂离子电池能量密度的提升。通过控制本申请第一涂层与正极极片之间的粘结力在上述范围内，能够进一步提高锂离子电池的结构稳定性和能量密度。
在本申请的一种实施方案中，第一聚合物的质量百分含量x与第一涂层与正极极片之间的粘结力F之间满足：F＝x·a。其中，a表示粘结力系数，5.0≤a≤30。第一聚合物在第一涂层中的含量x，与第一涂层与正极极片之间的粘结力F满足上述关系式时，能够得到粘结性能优异的第一涂层，从而进一步提高隔离膜的界面粘结性能。
在本申请的一种实施方案中，第一涂层中还包括辅助粘结剂，基于第一涂层的总质量，辅助粘结剂的质量百分含量为10％至40％。不限于任何理论，当辅助粘结剂在第一涂层中的含量过高时(例如高于40％)，第一聚合物的含量下降，使得颗粒状的第一聚合物带来的间隙减少，影响电解液在第一涂层界面间的传输，同时影响第一涂层与电极极片间的粘结力；当辅助粘结剂在第一涂层中的含量过低时(例如低于10％)，第一涂层内聚力较低，第一聚合物的粘结性能会随第一涂层内聚力的降低而下降。通过控制本申请辅助粘结剂的含量在上述范围内，能够进一步提高第一涂层与电极极片间的粘结力。
本申请对辅助粘结剂没有特别限制，只要能满足本申请要求即可，例如，辅助粘结剂可以包括丙烯酸乙酯、丙烯酸丁酯、甲基丙烯酸乙酯、苯乙烯、氯苯乙烯、氟苯乙烯、甲基苯乙烯、丙烯酸、甲基丙烯酸、马来酸、丙烯腈或丁二烯中的至少一种。在本申请的一种实施方案中，基材的一个表面包括第一涂层，基材的另一个表面包括第二涂层。
本申请第二涂层的厚度为0.2μm至4μm。第二涂层的厚度不宜过低或过高，第二涂层 的厚度过低时(例如低于0.2μm)，会使界面间粘结力不足，涂层粘结性能下降；第二涂层的厚度过高时(例如高于4μm)，加大了锂离子在隔离膜中的传输距离，影响锂离子电池的倍率性能。
在本申请的一种实施方案中，第二涂层包含第二聚合物，第二聚合物包括核壳结构的高分子聚合物或非核壳结构的高分子聚合物，基于第二涂层的总质量，第二聚合物的质量百分含量为78％至87.5％。通过控制第二聚合物的含量在上述范围内，能够得到具有良好界面粘结性能的第二涂层，从而提高锂离子电池整体的动力学性能，例如低温循环性能。
本申请对核壳结构的高分子聚合物和非核壳结构的高分子聚合物没有特别限制，例如，核壳结构的高分子聚合物的核主要成分可以为聚合物，该聚合物可以是一种聚合性单体聚合而成的均聚物，也可以两种或两种以上聚合性单体聚合而成的共聚物。具体地，核壳结构的高分子聚合物的核包括丙烯酸乙酯、丙烯酸丁酯、甲基丙烯酸乙酯、苯乙烯、氯苯乙烯、氟苯乙烯、甲基苯乙烯、丙烯酸、甲基丙烯酸或马来酸中的至少一种；核壳结构的高分子聚合物的壳也可以是一种聚合性单体的均聚物，或者是两种或两种以上聚合性单体的共聚物，所说的聚合性单体可以包括丙烯酸酯、芳香族单乙烯基化合物或腈化乙烯基化合物。具体地，核壳结构的高分子聚合物的壳包括丙烯酸甲酯、丙烯酸乙酯、丙烯酸丁酯、甲基丙烯酸甲酯、甲基丙烯酸乙酯、甲基丙烯酸丁酯、乙烯、氯苯乙烯、氟苯乙烯、甲基苯乙烯、丙烯腈或甲基丙烯腈中的至少一种。
非核壳结构的高分子聚合物包括丙烯酸、丙烯酸酯、丁二烯、苯乙烯、丙烯腈、乙烯、氯苯乙烯、氟苯乙烯或丙烯中的至少一种。
在本申请的一种实施方案中，第二涂层中还可以含有增稠剂、辅助粘结剂和润湿剂。增稠剂的作用是增加浆料稳定性，防止浆料沉降。本申请对增稠剂没有特别限制，只要能达到本申请发明目的即可，例如可以为羧甲基纤维素钠。辅助粘结剂起到辅助粘结的作用，以进一步提高第二涂层的粘结性能，本申请对辅助粘结剂没有特别限制，只要能达到本申请目的即可，例如，辅助粘结剂可以包括丙烯酸乙酯、丙烯酸丁酯、甲基丙烯酸乙酯、苯乙烯、氯苯乙烯、氟苯乙烯、甲基苯乙烯、丙烯酸、甲基丙烯酸、马来酸、丙烯腈或丁二烯的均聚物或共聚物中的至少一种。润湿剂的作用是降低浆料表面能，防止涂布漏涂，本申请对润湿剂没有特别限制，只要能达到本申请目的即可，例如，润湿剂可以包括二甲基硅氧烷、聚环氧乙烷，氧乙烯烷基酚醚、聚氧乙烯脂肪醇醚、聚氧乙烯聚氧丙烯嵌段共聚物或磺基丁二酸二辛基钠盐中的至少一种。
在本申请的一种实施方案中，基于第二涂层的总质量，第二聚合物的质量百分含量为78％至87.5％，辅助粘结剂的质量百分含量为5％至10％，增稠剂的质量百分含量为0.5％至2％，润湿剂的质量百分含量为7％至10％，能够得到具有优良粘结性能的第二涂层。
在本申请的一种实施方案中，第一涂层与所述基材之间和/或所述第二涂层与所述基材之间还设置有无机涂层，无机涂层的厚度为0.5μm至6μm。。
示例性地，第一涂层与所述基材之间设置有无机涂层；或者，第二涂层与所述基材之间设置有无机涂层；或者，第一涂层与所述基材之间以及第二涂层与所述基材之间设置有无机涂层，上述设置方法均能够进一步提高隔离膜的强度。
不限于任何理论，当无机涂层的厚度过低时(例如低于0.5μm)，隔离膜的强度下降，不利于锂离子电池循环性能的提升；当无机涂层的厚度过高时(例如高于6μm)，隔离膜整体变厚，不利于锂离子电池能量密度的提升。通过控制无机涂层的厚度在上述范围内，能够使锂离子电池的循环性能和能量密度均得到提升。
在本申请的一种实施方案中，无机涂层中包含无机粒子，无机粒子的Dv50为0.1μm至3μm。无机粒子的粒径不宜过大或过小，当无机粒子的粒径过大时(例如大于3μm)，难以实现无机涂层的薄涂布设计，影响锂离子电池的能量密度；当机粒子的粒径过小时(例如小于0.1μm)，导致无机粒子堆积孔隙减小，影响离子传输，从而影响锂离子电池的动力学性能。
本申请对无机粒子没有特别限制，只要能达到本申请目的即可，无机粒子包括勃姆石、氢氧化镁、氧化铝、二氧化钛、二氧化硅、二氧化锆、二氧化锡、氧化镁、氧化锌、硫酸钡、氮化硼、氮化铝或氮化硅中的至少一种。
在本申请的一种实施方案中，无机粒子可以为勃姆石，所述勃姆石的Dv50为0.1μm至3μm，长径比为1至3。通过控制勃姆石的粒径在上述范围内，能够进一步提高无机涂层的强度，从而提高隔离膜的性能。
本申请中，可以将隔离膜设置有第一涂层的一面与正极极片接触，将隔离膜具有第二涂层的一面与负极极片接触，使隔离膜与正极极片和负极极片间均具有良好的粘结效果，且隔离膜与正极极片间具有更好的电解液浸润性，从而改善锂离子电池的低温循环性能和快充循环性能。本申请的隔离膜具有锂离子透过性及电子阻隔性。
在本申请的一种实施方案中，第一聚合物为二次颗粒，二次颗粒的平均粒径D50为10μm至30μm。二次颗粒可以由第一聚合物的一次颗粒聚集形成，例如由PVDF一次颗粒 聚集形成的二次颗粒，使得二次颗粒的内部具有较多的空隙，电解液更容易渗透进这些空隙中，从而有利于提高隔离膜的电解液浸润性。
本申请的第一聚合物的制备方法没有特别限制，可以采用本领域技术人员的制备方法，例如可以采用如下制备方法：
对反应釜抽真空，抽氮气置换氧气后，向含有搅拌器的反应釜内加入去离子水、偏氟乙烯(VDF)、乳化剂全氟烷基羧酸盐、链转移剂异丙醇至反应釜压力为3.5MPa左右。然后升温至50℃至70℃，搅拌器转速70r/min至100r/min，开始聚合反应，同时不断补加偏氟乙烯单体保持反应釜压力3.5MPa，直到反应器中乳液固含量达到25％至30％停止反应，回收未反应单体，放出聚合物乳液，经离心、洗涤、干燥后，得到第一聚合物颗粒。
本申请对引发剂没有特别限制，只要能引发单体聚合即可，例如可以为二异丙苯过氧化氢。本申请对单体、去离子水、引发剂、链转移剂的添加量没有特别限制，只要能保证加入的单体发生聚合反应即可，例如去离子水为单体质量的5倍至10倍，引发剂占单体质量的0.05％至0.5％，乳化剂占单体质量的0.1％至1％，链转移剂占单体质量的3％至7％。
本申请中的正极极片没有特别限制，只要能够实现本申请目的即可。例如，正极极片通常包含正极集流体和正极活性材料层。其中，正极集流体可以为铝箔、铝合金箔或复合集流体等。正极活性材料层包括正极活性材料和导电剂，正极活性材料可以包括镍钴锰酸锂(811、622、523、111)、镍钴铝酸锂、磷酸铁锂、富锂锰基材料、钴酸锂、锰酸锂、磷酸锰铁锂或钛酸锂中的至少一种。导电剂可以包括导电炭黑(Super P)、碳纳米管(CNTs)、碳纳米纤维、鳞片石墨、乙炔黑、炭黑、科琴黑、碳点或石墨烯等中的至少一种。
本申请中的负极极片没有特别限制，只要能够实现本申请目的即可。例如，负极极片通常包含负极集流体和负极活性材料层。其中，负极集流体可以为铜箔、铝箔、铝合金箔以及复合集流体等。负极活性材料层包括负极活性材料，负极活性材料可以包括人造石墨、天然石墨、中间相碳微球、软碳、硬碳、硅、硅碳、钛酸锂等中的至少一种。
本申请的基材包括但不限于聚乙烯、聚丙烯、聚对苯二甲酸乙二醇酯、聚酰亚胺或芳纶中的至少一种。举例来说，聚乙烯包括选自高密度聚乙烯、低密度聚乙烯和超高分子量聚乙烯中的至少一种组分。尤其是聚乙烯和聚丙烯，它们对防止短路具有良好的作用，并可以通过关断效应改善锂离子电池的稳定性。
本申请的锂离子电池还包括电解质，电解质可以是凝胶电解质、固态电解质和电解液中的一种或多种，电解液包括锂盐和非水溶剂。在本申请一些实施方案中，锂盐选自LiPF 6、 LiBF 4、LiAsF 6、LiClO 4、LiB(C 6H 5) 4、LiCH 3SO 3、LiCF 3SO 3、LiN(SO 2CF 3) 2、LiC(SO 2CF 3) 3、LiSiF 6、LiBOB和二氟硼酸锂中的一种或多种。举例来说，锂盐可以选用LiPF 6，因为它可以给出高的离子导电率并改善循环特性。非水溶剂可为碳酸酯化合物、羧酸酯化合物、醚化合物、其它有机溶剂或它们的组合。上述碳酸酯化合物可为链状碳酸酯化合物、环状碳酸酯化合物、氟代碳酸酯化合物或其组合。
上述链状碳酸酯化合物的实例为碳酸二甲酯(DMC)、碳酸二乙酯(DEC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸甲乙酯(MEC)及其组合。环状碳酸酯化合物的实例为碳酸亚乙酯(EC)、碳酸亚丙酯(PC)、碳酸亚丁酯(BC)、碳酸乙烯基亚乙酯(VEC)及其组合。氟代碳酸酯化合物的实例为碳酸氟代亚乙酯(FEC)、碳酸1,2-二氟亚乙酯、碳酸1,1-二氟亚乙酯、碳酸1,1,2-三氟亚乙酯、碳酸1,1,2,2-四氟亚乙酯、碳酸1-氟-2-甲基亚乙酯、碳酸1-氟-1-甲基亚乙酯、碳酸1,2-二氟-1-甲基亚乙酯、碳酸1,1,2-三氟-2-甲基亚乙酯、碳酸三氟甲基亚乙酯及其组合。上述羧酸酯化合物的实例为甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸正丙酯、乙酸叔丁酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、γ-丁内酯、癸内酯、戊内酯、甲瓦龙酸内酯、己内酯及其组合。上述醚化合物的实例为二丁醚、四甘醇二甲醚、二甘醇二甲醚、1,2-二甲氧基乙烷、1,2-二乙氧基乙烷、乙氧基甲氧基乙烷、2-甲基四氢呋喃、四氢呋喃及其组合。上述其它有机溶剂的实例为二甲亚砜、1,2-二氧戊环、环丁砜、甲基环丁砜、1,3-二甲基-2-咪唑烷酮、N-甲基-2-吡咯烷酮、甲酰胺、二甲基甲酰胺、乙腈、磷酸三甲酯、磷酸三乙酯、磷酸三辛酯、磷酸酯及其组合。
本申请的第二方面提供了一种电化学装置，包括正极极片、负极极片、隔离膜和电解液，其中，所述隔离膜位于正极极片和负极极片之间，所述隔离膜为上述任一实施方案中所述的隔离膜，具有良好的低温循环性能。本申请的第三方面提供了一种电子装置，包含本申请实施方案中所述的电化学装置，具有良好的低温循环性能。
本申请的电子装置没有特别限定，其可以是用于现有技术中已知的任何电子装置。在一些实施例中，电子装置可以包括，但不限于，笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器等。
电化学装置的制备过程为本领域技术人员所熟知的，本申请没有特别的限制。例如锂离子电池可以通过以下过程制造：将正极和负极经由隔离膜重叠，并根据需要将其卷绕、折叠等操作后放入壳体内，将电解液注入壳体并封口，其中所用的隔离膜为本申请提供的上述隔离膜。此外，也可以根据需要将防过电流元件、导板等置于壳体中，从而防止锂离子电池内部的压力上升、过充放电。
本申请中，术语“Dv50”表示颗粒累积分布为50％的粒径，即小于此粒径的颗粒体积含量占全部颗粒的50％。
本申请提供了一种隔离膜及包含该隔离膜的电化学装置和电子装置，其中隔离膜包括基材和设置于基材的至少一个表面上的第一涂层，第一涂层中包含第一聚合物，本申请通过控制第一聚合物在第一涂层中的的含量和软化点同时在上述范围内，能够得到界面粘结性能优异、聚合物颗粒间间隙适中的第一涂层，有效提升隔离膜的粘结性能和电解液浸润性，从而提高锂离子电池的动力学性能，例如低温循环性能。
附图说明
为了更清楚地说明本申请和现有技术的技术方案，下面对实施例和现有技术中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例。
图1为本申请的第一种实施方案的隔离膜的结构示意图；
图2为本申请的第二种实施方案的隔离膜的结构示意图；
图3为本申请的第三种实施方案的隔离膜的结构示意图；
图4为本申请的第四种实施方案的隔离膜的结构示意图；
图5为本申请的第五种实施方案的隔离膜的结构示意图。
具体实施方式
为使本申请的目的、技术方案、及优点更加清楚明白，以下参照附图和实施例，对本申请进一步详细说明。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员所获得的所有其他技术方案，都属于本申请保护的范围。
如图1所示，本申请的隔离膜包括基材1，以及设置于基材1一个表面上的第一涂层2。
如图2所示，本申请的隔离膜包括基材1，以及分别设置于基材1的两个表面上的第一涂层2和第二涂层3。
在本申请的一种实施方案中，如图3所示，第一涂层2与基材1之间设置有无机涂层4。
在本申请的一种实施方案中，如图4所示，基材1与第二涂层3之间设置有无机涂层4。
在本申请的一种实施方案中，如图5所示，基材1与第一涂层2之间设置有无机涂层4，基材1与第二涂层3之间也设置有无机涂层4。
实施例
以下，举出实施例及对比例来对本申请的实施方式进行更具体地说明。各种的试验及评价按照下述的方法进行。另外，只要无特别说明，“份”、“％”为质量基准。
测试方法和设备：
隔离膜的第一涂层与正极极片间粘结力测试：
采用国家标准GB/T 2790-1995，即采用180°剥离测试标准测试隔离膜的第一涂层与正极极片之间的粘结力，将设置有第一涂层的隔离膜和正极极片裁切成54.2mm×72.5mm样品，将隔离膜具有第一涂层的一面与正极极片复合，使用热压机热压，热压条件为：温度85℃，压力1Mpa，热压时间85s(秒)，将复合好的样品裁切成15mm×54.2mm小条，按照180°剥离测试标准测试隔离膜的第一涂层与正极极片之间的粘结力。
隔离膜中第一涂层厚度测试：
1)基材厚度测试：常温环境下，取基材，沿TD方向裁切成50mm宽的样条，三个平行样，使用万分尺测厚仪(Mitutoyo Litematic VL-50B，测试头直径5mm，测试下压力0.01N)沿TD方向的中央位置均匀测试10个数据点，测试完3个平行样后，取30个测试数据的平均值d1作为基材的厚度；
2)涂布膜的总厚度测试：将第一涂层涂布在上述基材上，80℃下烘干，得到涂布有第一涂层的隔离膜；按照基材厚度测试方法测试，测试时，无涂层的一面向下；得到隔离膜的总厚度d2；
3)第一涂层厚度计算：d＝d2-d1。
锂离子电池低温性能测试：
1)：在25℃的环境中，对化成后的锂离子电池进行第一次充电和放电：在0.1C的充电电流下进行恒流和恒压充电，直到上限电压为4.45V，将充满电的锂离子电池静置5分钟；
2)：以0.2C倍率放电至3V，记录首次循环的放电容量，再静置5分钟；
3)：以1.5C的充电倍率先恒流充电至4.45V，在恒压充电到0.02C，然后静置5分钟；
4)：调节炉温至{25,10,0,-10,-20,45,60}℃，再静置5分钟，然后以0.2C倍率放电至3V，再静置5分钟；
5)：调节炉温至25℃，将锂离子电池静置60分钟；
6)：循环上述步骤4)至步骤5)，按照步骤4)中的温度条件依次测试各个温度条件后，依次记录在各温度条件下锂离子电池的最终放电容量，然后选取-20℃条件下记录的锂离子电池的最终放电容量，利用以下表达式计算锂离子电池在-20℃条件下的低温容量保持率：
低温容量保持率＝(-20℃条件下锂离子电池的最终放电容量/25℃条件下锂离子电池的首次循环的放电容量)×100％。
第一聚合物软化点测试：
采用通用型差示扫描量热仪(DSC)法：分别取5mg各实施例和对比例制备的第一聚合物样品，以5℃/min的升温速率升温至150℃，采集DSC曲线，由所得DSC曲线确定第一聚合物的软化点，也即软化温度。
第一涂层表面250μm×200μm面积内第一聚合物颗粒数量测试：
将涂有第一涂层的隔离膜裁切为10mm×10mm样品，然后将样品放置在SEM下以500倍放大倍率观察，并在视野中选取任意5个250μm×200μm区域，记录所选取区域中第一聚合物颗粒最大长度处于10μm至30μm之间的颗粒数量，然后取平均值，即为第一涂层单位面积区域内第一聚合物颗粒最大长度处于10μm至30μm之间的颗粒数量。
隔离膜离子阻抗测试：
1、对称电池的制备：
将隔离膜与电极极片复合成一个对称电池：对称电池中隔离膜的层数分梯度设计叠加，层数分别设置如下：2、4、6、8、10、12层隔膜，对称电池的两个电极极片均为未经过充放电循环的负极极片(即新鲜负极)。
2、隔离膜样品离子阻抗测试：
首先，采用化学工作站(EIS)对上述具有不同层数隔离膜设计的对称电池的隔离膜阻抗数值进行测试，然后，对测得的不同层数隔离膜设计的对称电池离子阻抗值进行梯度数据值拟合，再依据拟合结果计算出单层隔离膜的离子阻抗，单位为Ω。
1.5C放电倍率性能测试：
在25℃下，将化成后的锂离子电池以0.2C倍率恒流充电至4.45V，再恒压充电至电流小于等于0.05C，之后静置30分钟，再以0.2C倍率恒流放电至3.0V，测试得到锂离子电 池0.2C倍率放电容量。
在25℃下，将锂离子电池以0.2C倍率恒流充电至4.45V，再恒压充电至电流小于等于0.05C，之后静置30分钟，再以1.5C倍率恒流放电至3.0V，测试得到锂离子电池1.5C倍率放电容量。
锂离子二次电池1.5C倍率放电容量保持率(％)＝1.5C倍率放电容量/0.2C倍率放电容量×100％。
实施例1
<1-1.第一聚合物颗粒的制备>
对反应釜抽真空，抽氮气置换氧气后，向含有搅拌器的反应釜内加入去离子水、偏氟乙烯(VDF)、引发剂二异丙苯过氧化氢、乳化剂全氟烷基羧酸盐、链转移剂异丙醇至反应釜压力为3.5MPa，其中去离子水为偏氟乙烯单体质量的7倍，引发剂占偏氟乙烯单体质量的0.2％，乳化剂占偏氟乙烯单体质量的0.5％，链转移剂占偏氟乙烯单体质量的5％。然后升温至60℃，搅拌器转速80r/min，开始聚合反应，同时不断补加偏氟乙烯单体保持反应釜压力3.5MPa，直到反应器中乳液固含量达到25％停止反应，回收未反应单体，放出聚合物乳液，经离心、洗涤、干燥后，得到第一聚合物颗粒。该第一聚合物颗粒的软化点为120℃，Dv50为20μm。
<1-2.正极极片的制备>
将正极活性材料钴酸锂、乙炔黑、聚偏氟乙烯(PVDF)按质量比94∶3∶3混合，然后加入N-甲基吡咯烷酮(NMP)作为溶剂，调配成固含量为75％的浆料，并搅拌均匀。将浆料均匀涂布在厚度为12μm的铝箔的一个表面上，90℃条件下烘干，冷压后得到正极活性材料层厚度为100μm的正极极片，然后在该正极极片的另一个表面上重复以上步骤，得到双面涂布有正极活性材料层的正极极片。将正极极片裁切成74mm×867mm的规格并焊接极耳后待用。
<1-3.负极极片的制备>
将负极活性材料人造石墨、乙炔黑、丁苯橡胶及羧甲基纤维素钠按质量比96∶1∶1.5∶1.5混合，然后加入去离子水作为溶剂，调配成固含量为70％的浆料，并搅拌均匀。将浆料均匀涂布在厚度为8μm的铜箔的一个表面上，110℃条件下烘干，冷压后得到负极活性材料层厚度为150μm的单面涂布负极活性材料层的负极极片，然后在该负极极片的另一个表面上重复以上涂布步骤，得到双面涂布有负极活性材料层的负极极片。将负极极片裁切 成74mm×867mm的规格并焊接极耳后待用。
<1-4.隔离膜的制备>
将制备好的第一聚合物颗粒和辅助粘结剂丙烯腈按照质量比90∶10加入搅拌器中，搅拌混合均匀，再加入去离子水进行搅拌，调整浆料粘度100mPa·s，固含量为12％，得到浆料A；将浆料A均匀地涂布在厚度为5μm的PE基材的一个面上，得到厚度为20μm的第一涂层，在烘箱中完成干燥，得到隔离膜。
将所制得的隔离膜通过SEM在500倍放大倍率下观察，在第一涂层表面的任意250μm×200μm区域内(单位面积内)，第一聚合物颗粒最大长度处于10μm至30μm之间的颗粒数量在30个。
<1-5.电解液的制备>
在含水量小于10ppm的环境下，将非水有机溶剂碳酸乙烯酯(EC)、碳酸二乙酯(DEC)、碳酸亚丙酯(PC)、丙酸丙酯(PP)、碳酸亚乙烯酯(VC)按照质量比20∶30∶20∶28∶2混合，然后向非水有机溶剂中加入六氟磷酸锂(LiPF 6)溶解并混合均匀，得到电解液，其中，LiPF 6与非水有机溶剂的质量比为8∶92。
<1-6.锂离子电池的制备>
将上述制备的正极极片、隔离膜、负极极片按顺序叠好，将隔离膜具有第一涂层的一面与正极极片接触，卷绕得到电极组件。将电极组件装入铝塑膜包装袋中，并在80℃下脱去水分，注入配好的电解液，经过真空封装、静置、化成、整形等工序得到锂离子电池。
实施例2
除了在<隔离膜的制备>中，第一聚合物颗粒与辅助粘结剂的质量比85∶15(即第一聚合物百分含量为85％)以外，其余与实施例1相同。
实施例3
除了在<隔离膜的制备>中，第一聚合物颗粒与辅助粘结剂的质量比80∶20(即第一聚合物百分含量为80％)以外，其余与实施例1相同。
实施例4
除了在<隔离膜的制备>中，第一聚合物颗粒与辅助粘结剂的质量比75∶25(即第一聚合物百分含量为75％)以外，其余与实施例1相同。
实施例5
除了在<隔离膜的制备>中，第一聚合物颗粒与辅助粘结剂的质量比70∶30(即第一聚 合物百分含量为70％)以外，其余与实施例1相同。
实施例6
除了在<隔离膜的制备>中，第一聚合物颗粒与辅助粘结剂的质量比65∶35(即第一聚合物百分含量为65％)以外，其余与实施例1相同。
实施例7
除了在<隔离膜的制备>中，第一聚合物颗粒与辅助粘结剂的质量比60∶40(即第一聚合物百分含量为60％)以外，其余与实施例1相同。
实施例8
除了在<第一聚合物颗粒的制备>中，调整第一聚合物的软化点为90℃以外，其余与实施例4相同。
实施例9
除了在<第一聚合物颗粒的制备>中，调整第一聚合物的软化点为100℃以外，其余与实施例4相同。
实施例10
除了在<第一聚合物颗粒的制备>中，调整第一聚合物的软化点为110℃以外，其余与实施例4相同。
实施例11
除了在<第一聚合物颗粒的制备>中，调整第一聚合物的软化点为130℃以外，其余与实施例4相同。
实施例12
除了在<第一聚合物颗粒的制备>中，调整第一聚合物的软化点为140℃以外，其余与实施例4相同。
实施例13
除了在<第一聚合物颗粒的制备>中，调整第一聚合物的软化点为150℃以外，其余与实施例4相同。
实施例14
除了在实施例4中，将第一涂层的聚偏氟乙烯颗粒替换为质量分数为75％的偏氟乙烯和25％的六氟丙烯形成的共聚物以外，其余与实施例4相同。
实施例15
除了在实施例4中，将第一涂层的聚偏氟乙烯颗粒替换为质量分数为60％苯乙烯、25％丁二烯、15％丙烯酸形成的共聚物以外，其余与实施例4相同。
实施例16
除了在实施例4中，将第一涂层的聚偏氟乙烯颗粒替换为质量分数为70％苯乙烯、30％丙烯酸酯形成的共聚物以外，其余与实施例4相同。
实施例17
除了在实施例4中，将第一涂层的聚偏氟乙烯颗粒替换为质量分数为30％丙烯酸、35％丙烯腈、35％苯乙烯形成的共聚物以外，其余与实施例4相同。
实施例18
除了在<隔离膜的制备>中，第一涂层的厚度为3μm以外，其余与实施例4相同。
实施例19
除了在<隔离膜的制备>中，第一涂层的厚度为5μm以外，其余与实施例4相同。
实施例20
除了在<隔离膜的制备>中，第一涂层的厚度为8μm以外，其余与实施例4相同。
实施例21
除了在<隔离膜的制备>中，第一涂层的厚度为50μm以外，其余与实施例4相同。
实施例22
除了在<隔离膜的制备>中，第一涂层的厚度为10μm以外，其余与实施例4相同。
实施例23
除了在<隔离膜的制备>中，第一涂层的厚度为40μm以外，其余与实施例4相同。
实施例24
除了在<隔离膜的制备>中增加第二涂层、<锂离子电池的制备>与实施例4不同以外，其余与实施例4相同。
<第二涂层的制备>
将非核壳结构的聚合物粘结剂(由质量分数为80％的苯乙烯、10％的丙烯酸异丁酯以及10％的丙烯腈聚合而成的共聚物，Dv50为0.3μm)、增稠剂羧甲基纤维素钠、润湿剂二甲基硅氧烷按照质量比85∶14∶1加入搅拌器中搅拌混合均匀，然后加入去离子水进行搅拌，调整浆料的粘度为40mPa·s，固含量为5％，得到浆料B。将上述浆料B均匀地涂布在PE基材的另一个面上，得到厚度为2μm的第二涂层，在烘箱中完成干燥。
<锂离子电池的制备>
将上述制备的正极极片、隔离膜、负极极片按顺序叠好，将隔离膜具有第一涂层的一面与正极极片接触，将隔离膜具有第二涂层的一面与负极极片接触，并卷绕得到电极组件。将电极组件装入铝塑膜包装袋中，并在80℃下脱去水分，注入配好的电解液，经过真空封装、静置、化成、整形等工序得到锂离子电池。
实施例25
除了在<隔离膜的制备>中，调整第二涂层的厚度为0.2μm，其余与实施例24相同。
实施例26
除了在<隔离膜的制备>中，调整第二涂层的厚度为4μm，其余与实施例24相同。
实施例27
除了在<隔离膜的制备>中，如图3所示在第一涂层与基材之间设置无机涂层以外，其余与实施例24相同。无机涂层厚度为3μm，无机涂层中的无机粒子为勃姆石，Dv50为0.75μm，长径比为1。
实施例28
除了在<隔离膜的制备>中，调整无机涂层的厚度为0.5μm、勃姆石的Dv50为0.85μm以外，其余与实施例27相同。
实施例29
除了在<隔离膜的制备>中，调整无机涂层的厚度为6μm、Dv50为0.99μm以外，其余与实施例27相同。
实施例30
除了在<隔离膜的制备>中，如图4所示在第二涂层与基材之间设置无机涂层、无机涂层中的无机粒子选用Dv50为0.99μm的氧化铝以外，其余与实施例24相同。无机涂层厚度为3μm。
实施例31
除了在<隔离膜的制备>中，如图5所示在第一涂层与基材之间、以及第二涂层与基材之间均设置无机涂层、无机涂层中的无机粒子选用Dv50为0.99μm的氧化铝以外，其余与实施例24相同。无机涂层单层厚度为2μm。
实施例32
除了在<第一聚合物颗粒的制备>中，将所制得的第一聚合物一次颗粒聚集形成二次颗 粒以外，其余与实施例4相同。
<二次颗粒的制备>
将第一聚合物一次颗粒分散到去离子水中，使用MSK-SFM-10真空搅拌器，以公转转速为40rpm，自转转速为1500rpm搅拌120分钟，得到固含量为10％的一次颗粒浆料；
将一次颗粒浆料转移到喷雾干燥造粒机的离心转盘喷头，离心转速为2000rpm，形成微小雾滴。喷雾干燥造粒机进口温度为110℃，出口温度为100℃，冷却收集粉末，得到PVDF二次颗粒。
对比例1
除了在<隔离膜的制备>中，第一聚合物颗粒与辅助粘结剂的质量比95∶5(即第一聚合物百分含量为95％)以外，其余与实施例1相同。
对比例2
除了在<隔离膜的制备>中，第一聚合物颗粒与辅助粘结剂的质量比55∶45(即第一聚合物百分含量为55％)以外，其余与实施例1相同。
对比例3
除了在<第一聚合物颗粒的制备>中，调整第一聚合物的软化点为165℃以外，其余与实施例1相同。
对比例4
除了在<第一聚合物颗粒的制备>中，调整第一聚合物的软化点为70℃以外，其余与实施例1相同。
对比例5
除了在<第一聚合物颗粒的制备>中，除了调整第一聚合物颗粒与辅助粘结剂的质量比55∶45(即第一聚合物百分含量为55％)、第一聚合物的软化点为70℃以外，其余与实施例27相同。
各实施例和对比例的制备参数及测试结果如下表1和表2
表1
Figure PCTCN2021084661-appb-000001
Figure PCTCN2021084661-appb-000002
表2
Figure PCTCN2021084661-appb-000003
Figure PCTCN2021084661-appb-000004
Figure PCTCN2021084661-appb-000005
表2中，“-”表示未含有。
从实施例1至7和对比例1至2可以看出，随着第一聚合物在第一涂层中含量的增加，SEM下隔离膜表面单位面积内第一聚合物颗粒数量随之增加，隔离膜的第一涂层与正极极片之间的粘结力F逐渐减小。但是当第一聚合物的含量过高时(例如对比例1)影响第一涂层与正极之间的粘结力；当第一聚合物的含量过低时(例如对比例2)影响锂离子电池的低温容量保持率；从实施例4、8至13和对比例3至4可以看出，随着第一聚合物软化点的增加，第一涂层与正极极片间粘结力F呈下降趋势，锂离子电池的低温容量保持率总体呈上升趋势。但是当第一聚合物的软化点过高时(例如对比例3)影响第一涂层与电极极片间的粘结力；当第一聚合物的软化点过低时(例如对比例4)影响锂离子电池的低温容量保持率。可见，通过控制第一聚合物的含量和软化点同时在本申请范围内，能够得到界面间粘结性能、低温循环性能、倍率性能等综合性能更好的锂离子电池。
从实施例27和对比例5可以看出，通过控制第一聚合物的含量和软化点同时在本申请范围内，能够改善第一涂层的界面粘结性能及锂离子电池的低温循环性能。
第一聚合物的成分通常也会影响第一涂层的性能，从实施例1至17可以看出，包含本申请第一聚合物成分的第一涂层能够使锂离子电池具有优良的低温循环性能和倍率性能。
从实施例4、18至23可以看出，随着第一涂层厚度的增加，第一涂层与正极极片之间的粘结力F随之增加，锂离子电池的低温容量保持率总体呈上升趋势。从实施例4、18至20、22至23与实施例21可以看出，通过控制第一涂层的厚度在本申请范围内，能够进一步提高锂离子电池的离子传输能力、界面间粘结性能、低温循环性能及倍率性能。
第二涂层的厚度、无机涂层的厚度无机粒子的成分和粒径、以及第二涂层、无机涂层在隔离膜中的设置方式通常也会影响隔离膜的性能，从而对锂离子电池的动力学性能带来影响。从实施例24至31可以看出，只要使得第二涂层的厚度、无机涂层的厚度在本申请范围内，就能够得到具有优异低温循环性能的锂离子电池。
从实施例4和实施例32可以看出，包含第一聚合物二次颗粒的隔离膜具有更低的离子阻抗，这可能是由于二次颗粒的内部具有较多的空隙，电解液更容易渗透进这些空隙中，提高了本申请隔离膜的电解液浸润性。
以上所述仅为本申请的较佳实施例，并不用以限制本申请，凡在本申请的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本申请保护的范围之内。

Claims (19)

  1. 一种隔离膜，包括基材和设置于所述基材的至少一个表面上的第一涂层，
    其中，所述第一涂层中包括第一聚合物，基于所述第一涂层的总质量，所述第一聚合物的质量百分含量x为60％至90％，所述第一聚合物的软化点为90℃至150℃。
  2. 根据权利要求1所述的隔离膜，所述第一涂层的厚度为3μm至40μm。
  3. 根据权利要求1所述的隔离膜，在所述第一涂层表面的任意250μm×200μm区域内，所述第一聚合物颗粒最大长度处于10μm至30μm之间的颗粒数量在10个至30个。
  4. 根据权利要求1所述的隔离膜，其中，所述隔离膜的离子阻抗Z为0.5Ω至1.2Ω。
  5. 根据权利要求1所述的隔离膜，其中，所述第一聚合物的质量百分含量x与所述隔离膜的离子阻抗Z之间满足：
    Z＝x·b，其中，b表示第一离子阻抗系数，1≤b≤1.2。
  6. 根据权利要求1所述的隔离膜，其中，所述第一涂层与正极极片之间的粘结力F为3N/m至35N/m。
  7. 根据权利要求1所述的隔离膜，其中，所述第一聚合物的质量百分含量x与所述第一涂层与正极极片之间的粘结力F之间满足：
    F＝x·a，其中，a表示粘结力系数，5.0≤a≤30。
  8. 根据权利要求1所述的隔离膜，其中，所述第一涂层中还包括辅助粘结剂，基于所述第一涂层的总质量，所述辅助粘结剂的质量百分含量为10％至40％。
  9. 根据权利要求8所述的隔离膜，其中，所述辅助粘结剂包括丙烯酸乙酯、丙烯酸丁酯、甲基丙烯酸乙酯、苯乙烯、氯苯乙烯、氟苯乙烯、甲基苯乙烯、丙烯酸、甲基丙烯酸、马来酸、丙烯腈或丁二烯中的至少一种。
  10. 根据权利要求1所述的隔离膜，其中，所述第一聚合物包括偏氟乙烯、六氟丙烯、乙烯、丙烯、氯乙烯、氯丙烯、丙烯酸、丙烯酸酯、苯乙烯、丁二烯或丙烯腈中的至少一种。
  11. 根据权利要求1所述的隔离膜，其中，所述第一聚合物为二次颗粒，所述二次颗粒的粒径Dv50为10μm至30μm。
  12. 根据权利要求1所述的隔离膜，其中，所述基材的一个表面设置有第一涂层，所述基材的另一个表面设置有第二涂层，所述第二涂层的厚度为0.2μm至4μm。
  13. 根据权利要求12所述的隔离膜，其中，所述第二涂层包括第二聚合物，基于所述 第二涂层的总质量，所述第二聚合物的质量百分含量为78％至87.5％。
  14. 根据权利要求12所述的隔离膜，其中，所述第二涂层包括第二聚合物，所述第二聚合物包括核壳结构的高分子聚合物或非核壳结构的高分子聚合物，所述核壳结构的高分子聚合物的核包括丙烯酸乙酯、丙烯酸丁酯、甲基丙烯酸乙酯、苯乙烯、氯苯乙烯、氟苯乙烯、甲基苯乙烯、丙烯酸、甲基丙烯酸或马来酸中的至少一种；所述核壳结构的高分子聚合物的壳包括丙烯酸甲酯、丙烯酸乙酯、丙烯酸丁酯、甲基丙烯酸甲酯、甲基丙烯酸乙酯、甲基丙烯酸丁酯、乙烯、氯苯乙烯、氟苯乙烯、甲基苯乙烯、丙烯腈或甲基丙烯腈中的至少一种，所述非核壳结构的高分子聚合物选自丙烯酸、丙烯酸酯、丁二烯、苯乙烯、丙烯腈、乙烯、氯苯乙烯、氟苯乙烯或丙烯中的至少一种。
  15. 根据权利要求12所述的隔离膜，其中，所述第一涂层与所述基材之间和/或所述第二涂层与所述基材之间还设置有无机涂层，所述无机涂层的厚度为0.5μm至6μm。
  16. 根据权利要求15所述的隔离膜，其中，所述无机涂层中包含无机粒子，所述无机粒子包括勃姆石、氢氧化镁、氧化铝、二氧化钛、二氧化硅、二氧化锆、二氧化锡、氧化镁、氧化锌、硫酸钡、氮化硼、氮化铝或氮化硅中的至少一种，所述无机粒子的Dv50为0.1μm至3μm。
  17. 根据权利要求16所述的隔离膜，其中所述无机粒子为勃姆石，所述勃姆石的Dv50为0.1μm至3μm，长径比为1至3。
  18. 一种电化学装置，包括正极极片、负极极片、隔离膜和电解液，其中，所述隔离膜位于正极极片和负极极片之间，所述隔离膜为权利要求1-17中任一项所述的隔离膜。
  19. 一种电子装置，包含权利要求18所述的电化学装置。
PCT/CN2021/084661 2021-03-31 2021-03-31 隔离膜及包含该隔离膜的电化学装置和电子装置 WO2022205163A1 (zh)

Priority Applications (7)

Application Number Priority Date Filing Date Title
EP21933828.2A EP4318778A1 (en) 2021-03-31 2021-03-31 Separator, electrochemical apparatus including separator, and electronic apparatus
KR1020237032047A KR20230141893A (ko) 2021-03-31 2021-03-31 분리막 및 해당 분리막을 포함하는 전기화학 디바이스와 전자 디바이스
CN202180004688.9A CN114175384A (zh) 2021-03-31 2021-03-31 隔离膜及包含该隔离膜的电化学装置和电子装置
BR112023019956A BR112023019956A2 (pt) 2021-03-31 2021-03-31 Separador, dispositivo eletroquímico e dispositivo eletrônico
PCT/CN2021/084661 WO2022205163A1 (zh) 2021-03-31 2021-03-31 隔离膜及包含该隔离膜的电化学装置和电子装置
JP2023558637A JP2024510512A (ja) 2021-03-31 2021-03-31 セパレータならびに該セパレータを含む電気化学装置および電子装置
US18/478,175 US20240030551A1 (en) 2021-03-31 2023-09-29 Separator, electrochemical device containing same, and electronic device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2021/084661 WO2022205163A1 (zh) 2021-03-31 2021-03-31 隔离膜及包含该隔离膜的电化学装置和电子装置

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US18/478,175 Continuation US20240030551A1 (en) 2021-03-31 2023-09-29 Separator, electrochemical device containing same, and electronic device

Publications (1)

Publication Number Publication Date
WO2022205163A1 true WO2022205163A1 (zh) 2022-10-06

Family

ID=80489986

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/084661 WO2022205163A1 (zh) 2021-03-31 2021-03-31 隔离膜及包含该隔离膜的电化学装置和电子装置

Country Status (7)

Country Link
US (1) US20240030551A1 (zh)
EP (1) EP4318778A1 (zh)
JP (1) JP2024510512A (zh)
KR (1) KR20230141893A (zh)
CN (1) CN114175384A (zh)
BR (1) BR112023019956A2 (zh)
WO (1) WO2022205163A1 (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116315459A (zh) * 2023-05-23 2023-06-23 宁德新能源科技有限公司 隔膜、电化学装置以及电子设备

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023184443A1 (zh) * 2022-03-31 2023-10-05 宁德新能源科技有限公司 一种二次电池及包含该电池的装置
CN116435707B (zh) * 2023-06-09 2023-09-19 宁德新能源科技有限公司 电化学装置和电子装置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102610773A (zh) * 2012-03-06 2012-07-25 宁德新能源科技有限公司 一种聚合物锂离子电池及其隔膜
CN104600233A (zh) * 2015-02-04 2015-05-06 厦门大学 一种热关断复合隔膜及其应用
CN105440770A (zh) * 2014-06-30 2016-03-30 成都中科来方能源科技有限公司 用于改性锂离子电池用隔膜的水性组合物及改性隔膜和电池
CN108878748A (zh) * 2018-06-25 2018-11-23 宁德新能源科技有限公司 电化学装置
CN109148798A (zh) * 2018-08-08 2019-01-04 欣旺达电子股份有限公司 锂离子电池、涂层隔膜及其制备方法
CN111312971A (zh) * 2020-03-02 2020-06-19 荣盛盟固利新能源科技有限公司 一种隔膜、二次电池及其制备方法

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109473602B (zh) * 2017-09-07 2021-07-09 比亚迪股份有限公司 电池隔膜及其制备方法和锂电池
US20210036286A1 (en) * 2018-06-22 2021-02-04 Lg Chem, Ltd. Separator for Electrochemical Device, Electrochemical Device Comprising the Same and Manufacturing Method of the Separator

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102610773A (zh) * 2012-03-06 2012-07-25 宁德新能源科技有限公司 一种聚合物锂离子电池及其隔膜
CN105440770A (zh) * 2014-06-30 2016-03-30 成都中科来方能源科技有限公司 用于改性锂离子电池用隔膜的水性组合物及改性隔膜和电池
CN104600233A (zh) * 2015-02-04 2015-05-06 厦门大学 一种热关断复合隔膜及其应用
CN108878748A (zh) * 2018-06-25 2018-11-23 宁德新能源科技有限公司 电化学装置
CN109148798A (zh) * 2018-08-08 2019-01-04 欣旺达电子股份有限公司 锂离子电池、涂层隔膜及其制备方法
CN111312971A (zh) * 2020-03-02 2020-06-19 荣盛盟固利新能源科技有限公司 一种隔膜、二次电池及其制备方法

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116315459A (zh) * 2023-05-23 2023-06-23 宁德新能源科技有限公司 隔膜、电化学装置以及电子设备
CN116315459B (zh) * 2023-05-23 2023-09-05 宁德新能源科技有限公司 隔膜、电化学装置以及电子设备

Also Published As

Publication number Publication date
BR112023019956A2 (pt) 2023-11-14
JP2024510512A (ja) 2024-03-07
CN114175384A (zh) 2022-03-11
KR20230141893A (ko) 2023-10-10
US20240030551A1 (en) 2024-01-25
EP4318778A1 (en) 2024-02-07

Similar Documents

Publication Publication Date Title
JP5166356B2 (ja) リチウム電池
WO2022205163A1 (zh) 隔离膜及包含该隔离膜的电化学装置和电子装置
JP2022501784A (ja) セパレータ及び電気化学デバイス
CN113363671B (zh) 一种电化学装置及电子装置
WO2020140685A1 (en) Anode active material and anode using same, electrochemical device and electronic device
WO2022141448A1 (zh) 电化学装置、电子装置及电化学装置的制备方法
WO2022205165A1 (zh) 一种隔离膜及包含所述隔离膜的电化学装置和电子装置
WO2021243915A1 (zh) 锂离子电池及其装置
WO2022141508A1 (zh) 一种电化学装置和电子装置
US20240030554A1 (en) Separator and electrochemical apparatus and electronic apparatus including such separator
WO2023071691A1 (zh) 一种电化学装置及电子装置
WO2022120833A1 (zh) 一种电化学装置和电子装置
WO2022016378A1 (zh) 电池及电子装置
CN114128028A (zh) 用于电化学装置的复合隔板和包括该复合隔板的电化学装置
CN114188504B (zh) 一种电化学装置和电子装置
WO2024026702A1 (zh) 负极极片及其制备方法、二次电池、电池模块、电池包及用电装置
CN113728504B (zh) 聚合物粘结剂、叠层多孔膜、电池及电子装置
WO2024011356A1 (zh) 隔离膜、其制备方法及二次电池、电池模块、电池包和用电装置
US20220223854A1 (en) Negative electrode material and electrochemical apparatus and electronic apparatus containing same
WO2023225901A1 (zh) 隔离膜及其制备方法、二次电池、电池模块、电池包及用电装置
WO2021134279A1 (zh) 电化学装置及包含所述电化学装置的电子装置
WO2023184228A1 (zh) 一种电化学装置及电子装置
CN116864816A (zh) 一种电化学装置及电子装置
CN116454400A (zh) 电化学装置和包括其的电子装置
CN114094188A (zh) 一种电化学装置及包含该电化学装置的电子装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21933828

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 20237032047

Country of ref document: KR

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 1020237032047

Country of ref document: KR

WWE Wipo information: entry into national phase

Ref document number: 2023558637

Country of ref document: JP

REG Reference to national code

Ref country code: BR

Ref legal event code: B01A

Ref document number: 112023019956

Country of ref document: BR

WWE Wipo information: entry into national phase

Ref document number: 2021933828

Country of ref document: EP

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 112023019956

Country of ref document: BR

Kind code of ref document: A2

Effective date: 20230927

ENP Entry into the national phase

Ref document number: 2021933828

Country of ref document: EP

Effective date: 20231031