WO2023004820A1 - 隔离膜及其制备方法、电化学装置、电化学设备和用电装置 - Google Patents

隔离膜及其制备方法、电化学装置、电化学设备和用电装置 Download PDF

Info

Publication number
WO2023004820A1
WO2023004820A1 PCT/CN2021/109904 CN2021109904W WO2023004820A1 WO 2023004820 A1 WO2023004820 A1 WO 2023004820A1 CN 2021109904 W CN2021109904 W CN 2021109904W WO 2023004820 A1 WO2023004820 A1 WO 2023004820A1
Authority
WO
WIPO (PCT)
Prior art keywords
base film
optionally
heat
film
separator
Prior art date
Application number
PCT/CN2021/109904
Other languages
English (en)
French (fr)
Inventor
杨建瑞
赵丰刚
王连广
杨天乐
Original Assignee
宁德时代新能源科技股份有限公司
湖南中锂新材料有限公司
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 宁德时代新能源科技股份有限公司, 湖南中锂新材料有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to PCT/CN2021/109904 priority Critical patent/WO2023004820A1/zh
Priority to CN202180078478.4A priority patent/CN116802225A/zh
Priority to EP21943333.1A priority patent/EP4148890A1/en
Publication of WO2023004820A1 publication Critical patent/WO2023004820A1/zh

Links

Images

Classifications

    • 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
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/28—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum
    • 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
    • C08J5/18—Manufacture of films or sheets
    • 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
    • H01M10/42—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
    • H01M50/431—Inorganic material
    • H01M50/434—Ceramics
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/443—Particulate material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • 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
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/494—Tensile strength
    • 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
    • C08J2201/00—Foams characterised by the foaming process
    • C08J2201/04—Foams characterised by the foaming process characterised by the elimination of a liquid or solid component, e.g. precipitation, leaching out, evaporation
    • C08J2201/054—Precipitating the polymer by adding a non-solvent or a different solvent
    • C08J2201/0542—Precipitating the polymer by adding a non-solvent or a different solvent from an organic solvent-based polymer composition
    • C08J2201/0543—Precipitating the polymer by adding a non-solvent or a different solvent from an organic solvent-based polymer composition the non-solvent being organic
    • 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
    • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C08J2323/04—Homopolymers or copolymers of ethene
    • C08J2323/06—Polyethene
    • 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
    • C08J2423/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2423/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C08J2423/04—Homopolymers or copolymers of ethene
    • C08J2423/06—Polyethene
    • 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
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/0061—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof characterized by the use of several polymeric components
    • 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 application belongs to the technical field of energy storage devices, and in particular relates to an isolation film and a preparation method thereof, an electrochemical device, an electrochemical device and an electrical device.
  • electrochemical devices represented by secondary batteries have been widely used and promoted in industries such as various electronic products and new energy vehicles.
  • people have put forward higher requirements on the energy density of electrochemical devices.
  • One direction to increase the energy density of electrochemical devices is to reduce the weight or volume of components in the electrochemical devices.
  • a separator is usually provided in a secondary battery, and the weight and volume of the secondary battery can be reduced by reducing the thickness of the separator, so as to increase the energy density of the secondary battery.
  • the separator is a microporous porous film, which is used to isolate the positive electrode and the negative electrode, prevent the short circuit between the positive and negative electrodes inside the battery, and at the same time allow active ions to pass through, and also have the function of maintaining the electrolyte .
  • the small thickness of the separator leads to an increased risk of internal short circuit of the secondary battery, thus greatly challenging the safety performance of the secondary battery.
  • the first aspect of the present application provides a release film, including a base film, and the tensile energy per unit thickness of the base film in the longitudinal (Machine Direction, abbreviated as MD) direction and the transverse direction (Transverse Direction, abbreviated as TD) direction is ⁇ 1.8 J/10 ⁇ m, and the elongation of the base film in the MD direction and the TD direction are both ⁇ 150%;
  • the tensile energy per unit thickness is
  • F represents the force value in N when the sample whose gauge length of the base film is 40 mm and the width is 15 mm is stretched at a constant speed of 50 mm/min to fracture, and ⁇ L represents the force value in m when the stretch is broken.
  • the tensile displacement of the meter, d represents the initial thickness of the sample in ⁇ m;
  • the thickness of the base film is 2 ⁇ m ⁇ 40 ⁇ m.
  • the base film with a smaller thickness since the base film with a smaller thickness also satisfies the tensile energy per unit thickness and elongation in the MD direction within an appropriate range, and the tensile energy per unit thickness and elongation in the TD direction are within an appropriate range. Therefore, it can have high toughness and strength. Therefore, the separator can effectively inhibit the penetration of foreign particles, which greatly reduces the risk of short-circuit failure of electrochemical devices using the separator, such as secondary batteries.
  • the isolation film can also have high heat resistance, its shrinkage rate under heated conditions is small, and the pores formed by damage have low hole expansion rate under heated conditions.
  • the isolation film can still play a good isolation effect, thereby reducing the risk of thermal runaway of the electrochemical device. Therefore, the electrochemical device can have high safety performance.
  • the tensile energy per unit thickness of the base film in the MD direction is 1.8J/10 ⁇ m-50J/10 ⁇ m, optionally 2.4J/10 ⁇ m-50J/10 ⁇ m, and further optionally 2.7J /10 ⁇ m ⁇ 30J/10 ⁇ m. If the tensile energy per unit thickness of the base film in the MD direction is within an appropriate range, the anti-penetration ability of the separator can be further improved, and the rupture area when the separator is damaged can be reduced, thereby improving the safety performance of the electrochemical device.
  • the tensile energy per unit thickness of the base film in the TD direction is 1.8J/10 ⁇ m-50J/10 ⁇ m, optionally 2J/10 ⁇ m-50J/10 ⁇ m, and further optionally 2.5J/10 ⁇ m 10 ⁇ m ⁇ 30J/10 ⁇ m. If the tensile energy per unit thickness of the base film in the TD direction is within an appropriate range, the anti-penetration ability of the separator can be further improved, and the rupture area when the separator is damaged can be reduced, thereby improving the safety performance of the electrochemical device.
  • the elongation of the base film in the MD direction is 150%-4000%, optionally 180%-4000%, and further optionally 200%-2000%.
  • the elongation of the base film in the MD direction is within an appropriate range, so that the isolation film has a strong resistance to penetration by foreign objects. Even when the electrochemical device is mechanically damaged, the rupture area of the separator is relatively small, thereby reducing the damage caused by the mechanical damage. Therefore, the safety performance of the electrochemical device can be improved.
  • the elongation of the base film in the TD direction is 150%-4000%, optionally 180%-4000%, and further optionally 200%-2000%.
  • the elongation of the base film in the TD direction is within an appropriate range, so that the isolation film has a strong resistance to penetration by foreign objects. Even when the electrochemical device is mechanically damaged, the rupture area of the separator is relatively small, thereby reducing the damage caused by the mechanical damage. Therefore, the safety performance of the electrochemical device can be improved.
  • the thickness of the base film may be 2 ⁇ m-20 ⁇ m, may be 3 ⁇ m-15 ⁇ m, and may be 3 ⁇ m-10 ⁇ m.
  • the base film has an appropriate thickness, which not only enables the isolation film to have a better ability to resist penetration by foreign particles, but also helps to reduce the volume and weight of the electrochemical device. Therefore, the electrochemical device can have high safety performance and energy density.
  • the base film is a polymer base film, and based on the total mass of the polymer in the ingredients of the base film, the mass ratio of the polyethylene polymer in the base film is 50% or more , optionally more than 80%, further optionally 100%.
  • the polyethylene polymer includes one or more of polyethylene, copolymers of ethylene and ⁇ -olefin, optionally, the ⁇ -olefin is selected from propylene, 1-butene, and 1-octene one or more of.
  • the base film obtained by using the polyethylene polymer as the main polymer can have good strength and toughness, so that the isolation film can have a high resistance to penetration by foreign particles, thereby improving the safety performance of the electrochemical device.
  • the base film contains two or more polyethylene polymers, which satisfy: 1 ⁇ M1/M2 ⁇ 50, optionally, 2 ⁇ M1/M2 ⁇ 30, further optionally , 3 ⁇ M1/M2 ⁇ 10.
  • M1 represents the weight average molecular weight of the polyethylene polymer with the largest weight average molecular weight in the formulation of the base film
  • M2 represents the weight average molecular weight of the polyethylene polymer with the minimum weight average molecular weight in the formulation of the base film.
  • M1 is 1.1 million to 5 million, optionally 1.5 million to 3 million.
  • M2 is 100,000-1 million, optionally 300,000-1 million.
  • the mass proportion of the polyethylene-based polymer with the maximum weight-average molecular weight in the base film is 10% to 10%. 100%, optionally 10%-90%, further optionally 30%-70%. This helps to increase the puncture strength of the separator.
  • the mass proportion of the polyethylene polymer with the minimum weight average molecular weight in the base film is 0-90 %, optionally 10%-90%, further optionally 30%-70%. This helps the separator to obtain higher toughness. Therefore, the isolation film has a strong ability to resist foreign body puncture, and the rupture area is small when subjected to extreme mechanical damage such as puncture.
  • the crystallinity of the polyethylene-based polymer is ⁇ 65%, optionally ⁇ 50%, and further optionally ⁇ 45%.
  • the degree of crystallinity of the polyethylene-based polymer is within an appropriate range, enabling the separator to have high ductility. Therefore, the isolation film has a high ability to resist penetration by foreign particles, thereby improving the safety performance of the electrochemical device.
  • a heat-resistant layer is further included, and the heat-resistant layer is located on at least one surface of the base film.
  • the heat-resistant layer can improve the heat resistance of the separator.
  • the heat-resistant layer contains heat-resistant particles, and the mass ratio of the heat-resistant particles in the heat-resistant layer is ⁇ 40%, optionally 40% to 99%, and optionally 80% to 97%.
  • the heat-resistant layer contains a proper amount of heat-resistant particles, which can further improve the anti-penetration ability and heat resistance of the isolation film, thereby further improving the safety performance of the electrochemical device.
  • the heat-resistant particles may include one or more of inorganic heat-resistant particles and organic heat-resistant particles.
  • the heat-resistant inorganic particles can be selected from one or more of alumina, silicon oxide, titanium oxide, calcium carbonate, magnesium oxide, magnesium hydroxide, boehmite, barium titanate, and barium sulfate.
  • the organic heat-resistant particles can be selected from polyacrylic resin, aramid fiber, polyphenylene sulfide, polymethyl methacrylate, polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene fluoride-hexafluoropropylene One or more of the copolymers.
  • the thickness of the heat-resistant layer is ⁇ 0.1mm, optionally 0.1mm-10mm, and optionally 1mm-3mm.
  • the thickness of the heat-resistant layer satisfies the above conditions, which can effectively improve the anti-penetration ability and heat resistance of the isolation film.
  • the peel strength between the heat-resistant layer and the base film is ⁇ 10N/m, optionally 15N/m-200N/m, further optionally 20N/m-200N /m.
  • the interlayer adhesion of the isolation film is better, which can improve the anti-penetration ability and heat resistance of the isolation film.
  • the separator satisfies: (l M0 -l M )/l M0 ⁇ 100% ⁇ 30%, optionally, (l M0 -l M )/l M0 ⁇ 100% ⁇ 10 %, further optionally, (l M0 -l M )/l M0 ⁇ 100% ⁇ 5%, wherein l M represents that the MD direction length l M0 of the separator is 100mm and the TD direction length l T0 is 100mm The length in the MD direction in mm after the sample was kept at 130° C. for 1 h.
  • the separator satisfies: (l T0 -l T )/l T0 ⁇ 100% ⁇ 30%, optionally, (l T0 -l T )/l T0 ⁇ 100% ⁇ 10 %, further optionally, (l T0 -l T )/l T0 ⁇ 100% ⁇ 5%, wherein l T represents the test that the MD direction length l M0 of the separator is 100mm and the TD direction length l T0 is 100mm The length in mm in the TD direction of the sample after being kept at 130° C. for 1 h.
  • the shrinkage rate of the isolation film is small under heated conditions, which helps to further improve the safety performance of the electrochemical device.
  • the isolation membrane is pierced by a needle with a cross - sectional area of 0.5mm2, and after being kept at 150°C for 10 minutes, the hole expansion rate of the pinhole is ⁇ 8%, optionally ⁇ 5% %, further optionally ⁇ 4%, further optionally ⁇ 3%.
  • the hole expansion rate is (S 1 ⁇ S 0 )/S 0 ⁇ 100%, S 0 represents the initial area of the pinhole, and S 1 represents the area of the pinhole after being kept at 150° C. for 10 minutes.
  • the second aspect of the present application provides a method for preparing a separator, including:
  • the base film is used as an isolation film, or the base film is used as an isolation film after post-treatment;
  • the tensile energy per unit thickness of the base film in the longitudinal MD direction and the transverse TD direction is both ⁇ 1.8J/10 ⁇ m, and the elongation of the base film in the MD direction and the TD direction is both ⁇ 150%; the thickness of the base film 2 ⁇ m to 40 ⁇ m.
  • the thickness of the base film obtained according to the preparation method of the present application is relatively small, while also having appropriate tensile energy per unit thickness and elongation in the MD direction, and appropriate tensile energy and elongation per unit thickness in the TD direction, thereby obtaining High toughness and strength.
  • the electrochemical device using the isolation film can have higher safety performance.
  • post-processing the base film may include: (g) forming a heat-resistant layer on at least one surface of the base film.
  • a separator comprising a base film and a heat-resistant layer on the surface of the base film was obtained.
  • the cooling temperature in step (b) is 15°C to 30°C, optionally 20°C to 25°C.
  • the stretching ratio of the stretching in the MD direction in step (c) is 3 to 6 times, optionally 3 to 5 times, and optionally 3 to 4.5 times.
  • the stretching ratio of stretching in the TD direction in step (d) is 3-6 times, optionally 3-5 times, and optionally 3.5-5 times.
  • the heat setting in step (f) includes heat setting the porous sheet at a temperature above 130°C.
  • the optional temperature is from 130°C to 150°C, and also from 134°C to 145°C.
  • the third aspect of the present application provides an electrochemical device, which includes the separator according to the present application. Because the electrochemical device of the present application adopts the isolation film of the present application, it can obtain higher safety performance.
  • the fourth aspect of the present application provides an electrochemical device, which includes the electrochemical device according to the present application.
  • the electrochemical device of the present application includes the electrochemical device described in the present application, and thus has relatively high safety performance.
  • the fifth aspect of the present application provides an electrical device, which includes at least one of the electrochemical device or electrochemical device according to the present application.
  • the electrical device of the present application includes the electrochemical device or electrochemical equipment described in the present application, and thus has relatively high safety performance.
  • FIG. 1 is a scanning electron microscope (SEM) image with a magnification of 5000 times of a section of an isolation film provided by an embodiment of the present application.
  • FIG. 2 is a SEM image of the base film of the isolation film provided by an embodiment of the present application at a magnification of 5000.
  • Fig. 3 is an SEM image of the base film shown in Fig. 2 at a magnification of 20,000.
  • FIG. 4 is a schematic diagram of an embodiment of a secondary battery.
  • FIG. 5 is an exploded view of FIG. 4 .
  • FIG. 6 is a schematic diagram of an embodiment of a battery module.
  • FIG. 7 is a schematic diagram of an embodiment of a battery pack.
  • FIG. 8 is an exploded view of FIG. 7 .
  • Fig. 9 is a schematic diagram of an embodiment of a device in which a secondary battery is used as a power source.
  • ranges disclosed herein are defined in terms of lower and upper limits, and 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 and may be combined arbitrarily, ie 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, it is understood that ranges of 60-110 and 80-120 are also contemplated. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, 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" indicates that all real numbers between "0-5" have been listed in this article, and "0-5" is only an abbreviated representation of the combination of these values.
  • 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 in sequence, and may also include steps (b) and (a) performed in sequence.
  • steps (c) means that step (c) may be added to the method in any order, for example, 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) and so on.
  • the "comprising” and “comprising” mentioned in this application means open or closed.
  • the “comprising” and “comprising” may mean that other components not listed may be included or included, or only listed components may be included or included.
  • the term "or” is inclusive unless otherwise stated.
  • the phrase "A or B” means “A, B, or both A and B.” More specifically, the condition "A or B” is satisfied by either of the following: A is true (or 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).
  • the application provides a separator, the separator includes a base film, the tensile energy per unit thickness of the base film in the MD direction and the TD direction is both ⁇ 1.8J/10 ⁇ m, and the base film in the MD direction and the TD direction The elongation ratios are all ⁇ 150%, and the thickness of the base film is 2 ⁇ m ⁇ 40 ⁇ m.
  • the tensile energy per unit thickness is
  • F represents the force value in N when the sample whose gauge length of the base film is 40 mm and the width is 15 mm is stretched at a constant speed of 50 mm/min to fracture
  • ⁇ L represents the force value in m when the stretch is broken.
  • the tensile displacement in ⁇ m, d represents the initial thickness of the sample in ⁇ m.
  • five samples with a length of 100mm and a width of 15mm can be taken along the MD direction of the base film, where the length direction of the samples is parallel to the MD direction of the base film;
  • the gauge length of the sample to 40mm (that is, the distance between the fixtures), and perform the tensile test at a constant speed of 50mm/min.
  • the tensile energy and elongation per unit thickness of the base film in the TD direction were measured by referring to the above method.
  • the above tests were carried out at room temperature and normal pressure.
  • the test can use the tensile machine of Gaotie Testing Instrument Co., Ltd., such as AI-3000-S type.
  • the test can refer to the national standard GB/T 36363-2018.
  • the separator can effectively inhibit the penetration of foreign particles, which greatly reduces the risk of self-discharge and even thermal runaway due to short circuit in electrochemical devices using the separator, such as secondary batteries.
  • the isolation film can also have high heat resistance, its shrinkage rate is small under heated conditions, and the hole expansion rate of the damaged pores is relatively low under heated conditions. Therefore, when the electrochemical device using the isolation film is subjected to mechanical damage such as nail penetration, the isolation film can still play a good isolation role, thereby reducing the risk of fire and explosion in the electrochemical device. Therefore, the electrochemical device can have high safety performance.
  • the tensile energy per unit thickness of the base film in the MD direction is 1.8J/10 ⁇ m-100J/10 ⁇ m, optionally 1.8J/10 ⁇ m-50J/10 ⁇ m, 2.4J/10 ⁇ m-50J/10 ⁇ m, 2.7 J/10 ⁇ m ⁇ 50J/10 ⁇ m, 2.8J/10 ⁇ m ⁇ 50J/10 ⁇ m, 2.5J/10 ⁇ m ⁇ 45J/10 ⁇ m, or 2.7J/10 ⁇ m ⁇ 30J/10 ⁇ m.
  • the tensile energy per unit thickness of the base film in the MD direction is within an appropriate range, so that the mechanical strength of the separator in the MD direction is higher, so the separator has a higher resistance to penetration by foreign particles.
  • the isolation film also has appropriate flexibility in the MD direction, so that when the electrochemical device is mechanically damaged, the rupture area of the isolation film is small, thereby reducing the damage caused by the mechanical damage, and even enabling the electrochemical device Works fine for a short time.
  • the tensile energy per unit thickness of the base film in the TD direction is 1.8J/10 ⁇ m-100J/10 ⁇ m, optionally 1.8J/10 ⁇ m-50J/10 ⁇ m, 2J/10 ⁇ m-50J/10 ⁇ m, 2.4J /10 ⁇ m ⁇ 50J/10 ⁇ m, 2.8J/10 ⁇ m ⁇ 50J/10 ⁇ m, 2J/10 ⁇ m ⁇ 45J/10 ⁇ m, or 2.5J/10 ⁇ m ⁇ 30J/10 ⁇ m.
  • the tensile energy per unit thickness of the base film in the TD direction is within an appropriate range, so that the mechanical strength of the separator in the TD direction is higher, so the separator has a higher resistance to penetration by foreign particles.
  • the isolation film also has proper flexibility in the TD direction, so that when the electrochemical device is mechanically damaged, the rupture area of the isolation film is small, thereby reducing the damage caused by the mechanical damage, and even enabling the electrochemical device Works fine for a short time.
  • the elongation of the base film in the MD direction is 150%-4000%, optionally 180%-4000%, 180%-3000%, 200%-3000%, 250%-3000%, 200% % to 2000%, or 250% to 2000%.
  • the elongation of the base film in the MD direction is in an appropriate range, so that the flexibility of the isolation film in the MD direction is better, and the mechanical strength is higher. Therefore, the isolation film has a strong resistance to penetration by foreign matter. Even when the electrochemical device is mechanically damaged, the rupture area of the isolation film is relatively small, so the damage caused by the mechanical damage can be reduced, and the electrochemical device can even work normally in a short time.
  • the elongation of the base film in the TD direction is 150%-4000%, optionally 180%-4000%, 180%-3000%, 200%-3000%, 250%-3000%, 200% % to 2000%, or 250% to 2000%.
  • the elongation of the base film in the TD direction is in an appropriate range, so that the flexibility of the isolation film in the TD direction is better, and the mechanical strength is higher. Therefore, the isolation film has a strong ability to resist foreign matter puncture. Even when the electrochemical device is mechanically damaged, the rupture area of the isolation film is relatively small, so the damage caused by the mechanical damage can be reduced, and the electrochemical device can even work normally in a short time.
  • the base film has a thickness of 2 ⁇ m-30 ⁇ m, optionally 2 ⁇ m-20 ⁇ m, 3 ⁇ m-15 ⁇ m, 3 ⁇ m-10 ⁇ m, 7 ⁇ m-12 ⁇ m, 5 ⁇ m-10 ⁇ m, or 2 ⁇ m-9 ⁇ m.
  • the base film has an appropriate thickness, which can not only make the separator have better resistance to penetration by foreign particles, so as to effectively isolate the positive and negative electrodes, but also help to reduce the volume and weight of the electrochemical device. Therefore, the electrochemical device can have high safety performance and energy density.
  • the base film is a polymeric base film.
  • the polymer is mainly polyethylene polymer.
  • the mass proportion of polyethylene-based polymers in the base film is more than 50%, optionally more than 80%, and further optionally 100% .
  • Polyethylene polymers include one or more of polyethylene (PE), copolymers of ethylene and ⁇ -olefin.
  • the ⁇ -olefin may be selected from ⁇ -olefins having 3 to 10 carbon atoms.
  • the ⁇ -olefin is selected from one or more of propylene, 1-butene, and 1-octene.
  • the copolymer of ethylene and ⁇ -olefin may include one of polyethylene-propylene copolymer, polyethylene-butene copolymer, polyethylene-propylene-butene copolymer, polyethylene-octene copolymer, or Several kinds.
  • the base film obtained by using the polyethylene polymer as the main polymer can have good strength and toughness, so that the isolation film can have a high resistance to penetration by foreign particles, thereby improving the safety performance of the electrochemical device.
  • copolymers described herein may be random copolymers.
  • random means that the comonomers are arranged randomly (ie, in a random distribution) on the molecular chains of the copolymer.
  • the base film may contain two or more polyethylene-based polymers, which satisfy: 1 ⁇ M1/M2 ⁇ 50; alternatively, 1.2 ⁇ M1/M2 ⁇ 30, 2 ⁇ M1/M2 ⁇ 30 , 2 ⁇ M1/M2 ⁇ 10, 3 ⁇ M1/M2 ⁇ 10, or 3 ⁇ M1/M2 ⁇ 6.
  • M1 represents the weight-average molecular weight of the polyethylene-based polymer with the largest weight-average molecular weight in the formulation of the base film
  • M2 represents the weight-average molecular weight of the polyethylene-based polymer with the smallest weight-average molecular weight in the formulation of the base film.
  • the base film adopts two or more polyethylene polymers, and the molecular weights of the two or more polyethylene polymers satisfy an appropriate relationship, so that the isolation film as a whole has better uniformity. Therefore, the anti-penetration ability of foreign particles at all parts of the isolation film is higher, thereby better improving the safety performance of the electrochemical device.
  • the isolation film can also have high heat resistance, and the hole expansion rate under heated conditions after being pierced is relatively small. Therefore, the separator can fully and effectively play the role of isolating the positive and negative electrodes in the electrochemical device, further improving the safety performance of the electrochemical device.
  • the weight ratio W1 of the polyethylene-based polymer with the largest weight-average molecular weight in the base film is 10% to 100%. In some embodiments, W1 ⁇ 100%, optionally, W1 is 10%-90%, 20%-80%, 30%-70%, 25%-60%, or 30%-50%. When W1 is in an appropriate range, it is helpful to improve the puncture resistance strength of the separator.
  • the weight ratio W2 of the polyethylene-based polymer with the minimum weight average molecular weight in the base film is 0-90%. In some embodiments, W2>0, optionally, W2 is 10%-90%, 20%-80%, 30%-70%, 40%-75%, or 50%-70%. W2 in an appropriate range helps the separator to obtain higher toughness. Therefore, the isolation film has a strong ability to resist foreign body puncture, and the rupture area is small when subjected to extreme mechanical damage such as puncture.
  • M1 may be 1.1 million to 5 million, or 1.5 million to 3 million, or 1.5 million to 2.5 million.
  • M2 may be 100,000-1 million, or 300,000-1 million, or 400,000-800,000.
  • the polyethylene polymer has an appropriate molecular weight, which can improve the toughness and strength of the base film, so it can improve the resistance of the separator to the penetration of foreign particles, and effectively reduce the risk of the separator being punctured, thus greatly reducing the risk of the separator being punctured. The potential for thermal runaway of the battery due to wear.
  • the polyethylene-based polymer has a crystallinity of ⁇ 65%, alternatively ⁇ 60%, ⁇ 55%, ⁇ 50%, or ⁇ 45%.
  • the crystallinity of the polyethylene polymer is low, and the degree of orientation of the obtained separator is small, which is beneficial to improve the elongation of the separator and make the separator have high ductility. Therefore, the isolation film has a higher ability to resist penetration by foreign particles, further improving the safety performance of the electrochemical device.
  • the polyethylene-based polymer has a crystallinity of > 20%, > 25%, > 30%, > 35%, > 40%, or > 45%. The crystallinity of the polyethylene-based polymer within the given range enables the separator to have high strength.
  • the base film may optionally employ other polymers known in the art in addition to polyethylene-based polymers.
  • other polymers may include polyolefins (such as polypropylene, polybutene, etc.), polyimides (such as isophthalic polyimide, polyamide-imide, and the like) other than polyethylene-based polymers.
  • polyetherimide, etc. polyamide (such as aramid, etc.), polyester (such as polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, etc.) , polyurethane, polycarbonate, polyacetal, polyether ether ketone, polyphenylene sulfide, fluoropolymers (such as polyvinylidene fluoride PVDF, polyvinylidene fluoride-hexafluoropropylene copolymer PVDF-HFP, polytetrafluoroethylene One or more of ethylene PTFE, etc.).
  • fluoropolymers such as polyvinylidene fluoride PVDF, polyvinylidene fluoride-hexafluoropropylene copolymer PVDF-HFP, polytetrafluoroethylene One or more of ethylene PTFE, etc.
  • the base film is a microporous porous film.
  • the porosity of the base film is 20%-80%, optionally 20%-40%, and further optionally 25%-38%.
  • the porosity of the base film is in an appropriate range, which helps the isolation film to have a proper electrolyte retention, thereby enabling the electrochemical device to take into account both high cycle performance and energy density.
  • the air permeability of the base film is 30s/100cc-300s/100cc, optionally 50s/100cc-250s/100cc, further optionally 80s/100cc-200s/100cc. If the air permeability of the base film is in an appropriate range, it is convenient for ions to pass through the isolation film, thereby helping the electrochemical device to have higher capacity performance and cycle performance.
  • the separator further includes a heat-resistant layer.
  • the heat-resistant layer may be located on at least one surface of the base film.
  • the base film has two surfaces facing each other in its thickness direction, and the heat-resistant layer may be located on any one or both of the two surfaces.
  • the heat-resistant layer contains heat-resistant particles. Ions can form channels between particles to pass through.
  • the heat-resistant particles may include one or more of inorganic heat-resistant particles and organic heat-resistant particles.
  • the inorganic heat-resistant particles may be selected from one or more of aluminum oxide, silicon oxide, titanium oxide, calcium carbonate, magnesium oxide, magnesium hydroxide, boehmite, barium titanate, and barium sulfate.
  • the organic heat-resistant particles can be selected from polyacrylic resin, aramid fiber, polyphenylene sulfide, polymethyl methacrylate, polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene fluoride-hexafluoropropylene copolymer one or more of.
  • the heat-resistant particles include inorganic heat-resistant particles.
  • the heat-resistant layer can improve the strength of the isolation film, thereby further enhancing the ability of the isolation film to resist penetration by foreign particles.
  • the heat-resistant layer can improve the heat resistance of the separator.
  • the mass proportion of heat-resistant particles in the heat-resistant layer is ⁇ 40%, optionally 40%-99%, 60%-99%, 80%-99%, 80%-97%, 80% to 95%, 80% to 90%, 90% to 97%, or 85% to 95%.
  • the heat-resistant layer contains a proper amount of heat-resistant particles, which can further improve the anti-penetration ability and heat resistance of the isolation film, thereby further improving the safety performance of the electrochemical device.
  • the heat-resistant layer includes a binder.
  • the binder can bond the heat-resistant particles to the base film, and achieve higher peel strength between the heat-resistant layer and the base film.
  • the binder used for the heat-resistant layer include polyacrylate, polybutadiene-styrene copolymer, polyacrylic acid, polypropylene cyanide-acrylic acid copolymer, polytetrafluoroethylene, polyvinylidene fluoride, One or more of polymethyl methacrylate, polyvinylidene fluoride-hexafluoropropylene copolymer.
  • the thickness of the heat-resistant layer is > 0.1 mm.
  • the thickness of the heat-resistant layer is 0.1mm-10mm, 0.5mm-8mm, 0.1mm-5mm, 1mm-5mm, or 1mm-3mm. The thickness of the heat-resistant layer satisfies the above conditions, which can effectively improve the anti-penetration ability and heat resistance of the isolation film.
  • the peel strength between the heat-resistant layer and the base film is ⁇ 10N/m, optionally 10N/m-200N/m, 15N/m-200N/m, 15N/m-100N/m, 20N/m ⁇ 50N/m, 20N/m ⁇ 200N/m, 30N/m ⁇ 200N/m, or 40N/m ⁇ 200N/m.
  • the higher the peel strength between the heat-resistant layer and the base film the better the interlayer adhesion of the separator. Therefore, the resistance to penetration by foreign particles and heat resistance of the separator are further improved.
  • the isolation film satisfies: thermal shrinkage rate in MD direction (l M0 -l M )/l M0 ⁇ 100% ⁇ 30%, optionally, (l M0 -l M )/l M0 ⁇ 100% ⁇ 20%, ⁇ 15%, ⁇ 12%, ⁇ 10%, ⁇ 5%, ⁇ 3%, or ⁇ 2.5%.
  • l M represents the length in mm of the MD direction of the separator whose length in the MD direction l M0 is 100 mm and the length in the TD direction l T0 is 100 mm after being kept at 130°C for 1 h.
  • the separator satisfies: thermal shrinkage rate in TD direction (l T0 -l T )/l T0 ⁇ 100% ⁇ 30%, optionally, (l T0 -l T )/l T0 ⁇ 100% ⁇ 20%, ⁇ 15%, ⁇ 12%, ⁇ 10%, ⁇ 5%, ⁇ 3%, or ⁇ 2.5%.
  • l T represents the length in mm of the TD direction of a sample whose MD direction length l M0 of the separator is 100 mm and the TD direction length l T0 is 100 mm after being kept at 130° C. for 1 h.
  • the separator can be cut into a sample whose MD direction length l M0 is 100 mm and TD direction length l T0 is 100 mm.
  • the MD direction of the sample is parallel to the MD direction of the separator, and the TD direction of the sample is parallel to the TD direction of the separator. ; Place the sample in a 130°C oven and heat it for 1h; test the length of the sample in the MD direction l M or the length of the TD direction l T after heating, and calculate the thermal shrinkage rate in the MD or TD direction.
  • the test can refer to the national standard GB/T 36363-2018.
  • the shrinkage rate of the isolation film is small under heated conditions, so the heat resistance is high, which helps to further improve the safety performance of the electrochemical device.
  • the isolation membrane is pierced by a needle with a cross - sectional area of 0.5mm2, and after being kept at 150°C for 10 minutes, the hole expansion rate of the pinhole is ⁇ 8%, optionally ⁇ 7%, ⁇ 6 %, ⁇ 5%, ⁇ 4.5%, ⁇ 4%, ⁇ 3%, or ⁇ 2.5%.
  • the hole expansion rate is (S 1 ⁇ S 0 )/S 0 ⁇ 100%, S 0 represents the initial area of the pinhole, and S 1 represents the area of the pinhole after being kept at 150° C. for 10 minutes.
  • the cross-sectional area of the needle is, for example, circular. S 0 and S 1 can be tested using instruments and methods known in the art, respectively. For example a microscope.
  • the separator is pierced by a needle, the pinhole expansion rate under heated conditions is small, and its heat resistance is high, especially the small rupture area can reduce the risk of thermal runaway of the electrochemical device.
  • the crystallinity of polyethylene polymers is a well-known meaning in the art, and can be tested by using instruments and methods known in the art.
  • An exemplary test method is as follows: the melting enthalpy of the polyethylene-based polymer is measured by differential scanning calorimetry (DSC), and then divided by the melting enthalpy of the polyethylene-based polymer with 100% crystallinity to obtain the degree of crystallinity.
  • DSC differential scanning calorimeter
  • the test can refer to the standard GB/T 19466.3-2004.
  • the weight-average molecular weight of polyethylene-based polymers is a well-known meaning in the art, and can be tested by using instruments and methods known in the art. For example high temperature gel chromatography. The test can be performed using a gel permeation chromatography (GPC) instrument, such as a Polymer Char GPC-IR high temperature gel chromatograph. The test can refer to the international standard ISO 16014-1-2019.
  • GPC gel permeation chromatography
  • the thicknesses of the base film, isolation film and heat-resistant layer all have meanings known in the art, and can be tested using instruments and methods known in the art.
  • An exemplary test method for the thickness of the separator is as follows: take a sample with a length of 500 mm ⁇ a width of 100 mm; take 5 points evenly on the sample (for example, take a point at intervals of 100 mm along the length of the sample), and use a multimeter thickness gauge to test the 5 points.
  • the thickness of the isolation film at different positions, and the average value is taken as the thickness of the isolation film.
  • the length direction of the sample is parallel to the TD direction of the separator.
  • the thickness of the base film can be tested by referring to the above method.
  • the thickness of the heat-resistant layer is obtained by subtracting the thickness of the base film from the thickness of the isolation film. If the opposite sides of the isolation film are respectively provided with the heat-resistant layer to be tested and the heat-resistant layer on the opposite side of the heat-resistant layer to be tested, the thickness of the isolation film is subtracted from the sum of the thickness of the base film and the heat-resistant layer on the opposite side, which is The thickness of the heat-resistant layer to be tested.
  • the porosity of the base film is a well-known meaning in the art, and can be tested by using instruments and methods known in the art.
  • the peel strength between the heat-resistant layer and the base film is a well-known meaning in the art, and can be tested by using instruments and methods known in the art.
  • the stretching equipment can adopt the tensile machine of the high-speed rail testing instrument company, such as the AI-3000-S type.
  • FIG. 1 shows a separator as an example.
  • the isolation film includes a base film 10 and a heat-resistant layer 20 laminated on any surface of the base film 10 .
  • the base film 10 is a microporous porous film.
  • the heat-resistant layer 20 is a microporous porous film layer containing heat-resistant particles.
  • the isolation film of FIG. 1 is merely exemplary.
  • the isolation film may include a base film 10 and a heat-resistant layer 20 laminated on two surfaces of the base film 10 opposite in the thickness direction.
  • the present application also provides a preparation method of the isolation film.
  • the isolation film described in this application can be prepared.
  • the preparation method comprises steps (a) to (f).
  • the polymer of step (a) may be selected from those as described herein, eg, from polyethylene-based polymers.
  • the pore-forming agent substances known in the art for forming porous structures in polymer films, such as paraffin oil, can be used.
  • the weight ratio of the polymer to the porogen may be 20:80-60:40, further optionally 35:75-50:50, or 30:70-40:60.
  • the polymer containing polymer can be compounded with paraffin oil to form a molten base film formulation.
  • the mixing temperature may be 180°C-250°C, optionally 190°C-245°C.
  • Kneading can be carried out by devices known in the art, such as an extruder, further such as a twin-screw extruder.
  • step (b) may extrude the molten base film formulation through a forming die, and cast it in sheet form onto a cooling roll, thereby cooling to form a sheet.
  • the cooling temperature may be 15°C to 30°C, further optionally 15°C to 25°C, or 20°C to 25°C. Due to the low cooling temperature, the polymer can be cooled rapidly, thereby reducing the crystallinity of the base film, thereby increasing the elongation.
  • the melted base film ingredients pass through the gear pump and filter of the extruder, and then are uniformly extruded through a double-channel cross die.
  • the extruded base film ingredients are cast vertically onto the cooling rolls of the casting unit, and are cooled to form a sheet.
  • the cooling roll can be cooled by pure water freezing to achieve the required cooling temperature.
  • the stretching in the MD direction of step (c) can be carried out using methods and devices known in the art.
  • longitudinal stretching machine for example longitudinal stretching machine.
  • the stretching ratio of stretching in the MD direction is 3-6 times, optionally 3-5 times, 3-4.5 times, 3.5-4.5 times, 3-4 times, or 4-5 times.
  • the stretching ratio in the MD direction is within an appropriate range, which can reduce the degree of orientation of the base film in the MD direction and increase the elongation of the base film while ensuring the strength of the base film.
  • the stretching in the MD direction in step (c) can be carried out at a temperature of 90°C to 120°C.
  • the thickness of the sheet after being stretched in the MD direction may be 0.3 mm ⁇ 0.1 mm. In this way a base film of smaller thickness can be obtained.
  • the stretching in the TD direction of step (d) can be carried out using methods and devices known in the art. Such as horizontal drawing machine.
  • the sheet is drawn into a first cross-drawing machine (TDO1) for TD direction stretching.
  • the first horizontal drawing machine can include three areas of preheating, stretching and setting.
  • the temperature for stretching in the TD direction in step (d) can be set at 90°C to 120°C.
  • the stretching ratio in the TD direction of step (d) is 3 to 6 times, optionally 3 to 5 times, 3 to 4.5 times, 3.5 to 4.5 times, 3.5 to 5 times, Or 4 to 5 times, etc.
  • the preparation method of the present application first implements step (c) of stretching in MD direction, and then implements step (d) of stretching in TD direction. This can better improve the strength and elongation of the base film.
  • the porogen may be removed from the sheet by means known in the art to form a porous sheet.
  • extractant extraction is used to remove the porogen.
  • extractants include dichloromethane.
  • Extraction can be performed in apparatus known in the art.
  • the sheet can be pulled to an extraction section with an internal circulation extraction device, and the internal circulation extraction method is used, the film is backwashed in the extractant, and the pore-forming agent in the sheet is completely removed by the extractant.
  • the extracted sheet is dried to obtain a porous sheet. Drying can be performed in apparatus known in the art, such as a drying oven.
  • step (e) may be performed after steps (c) and (d). This can better improve the strength and elongation of the base film.
  • heat setting step (f) may comprise heat setting the porous sheet at a temperature above 130°C.
  • the heat setting temperature is 130°C to 150°C, and may also be selected to be 134°C to 145°C.
  • the degree of orientation in the TD direction of the base film increases after being stretched in the TD direction. If the heat-setting temperature is in an appropriate range, the degree of orientation of the base film in the TD direction can be appropriately reduced, thereby increasing the elongation of the base film.
  • step (f) methods and devices known in the art can be used to heat-set the porous sheet.
  • Such as horizontal drawing machine the porous sheet may be drawn into a second cross-drawing machine (TDO2) for heat setting.
  • TDO2 second cross-drawing machine
  • the second horizontal drawing machine can include three areas of preheating, stretching and setting.
  • the sheet can be stretched in the TD direction to ensure its tension.
  • the stretch ratio in the TD direction is 1-1.2, or 1.05-1.15.
  • the base film obtained after heat-setting treatment can be rolled up for later use.
  • the base film can be used as a separator.
  • the base film can also be used as a separator after post-treatment.
  • a heat insulating layer is formed on the base film.
  • the preparation method of the isolation film may further include step (g), forming a heat-resistant layer on at least one surface of the base film.
  • the heat-resistant layer may be formed on any one surface or both surfaces in the thickness direction of the base film itself.
  • the heat-resistant layer can be formed by coating at least one surface of the base film with a slurry containing heat-resistant particles and drying.
  • the heat resistant particles may be selected from those as described herein.
  • the solvent of the slurry can be one or more of aqueous solvents (such as deionized water, etc.) and organic solvents (such as N-methylpyrrolidone NMP, dimethylacetamide DMAC, acetone, etc.).
  • the slurry may also contain a binder.
  • the binder may be selected from those as described herein.
  • the coating method of the slurry may be any one or several methods of gravure coating (such as micro gravure coating), dip coating, doctor blade coating, wire bar coating, spray coating and electrospinning.
  • the present application also provides an electrochemical device.
  • the electrochemical device includes any one or several separators of the present application. Therefore, the electrochemical device can have high safety performance.
  • the electrochemical device of the present application can be any device capable of electrochemical reaction using a separator that can be imagined by those skilled in the art.
  • the electrochemical device may be a primary battery, a secondary battery, a fuel cell, a solar cell, a capacitor, or the like.
  • the electrochemical device of the present application is a secondary battery.
  • secondary batteries include, but are not limited to, lithium ion secondary batteries, sodium ion secondary batteries, potassium ion secondary batteries, magnesium ion secondary batteries, and the like.
  • a secondary battery includes a positive pole piece, a negative pole piece, a separator, and an electrolyte.
  • active ions are intercalated and extracted back and forth between the positive electrode and the negative electrode.
  • the electrolyte plays the role of conducting ions between the positive pole piece and the negative pole piece.
  • the separator is arranged between the positive pole piece and the negative pole piece to play the role of isolation.
  • the positive pole piece includes a positive current collector and a positive film layer arranged on the positive current collector.
  • the positive electrode current collector has two opposing surfaces in its own thickness direction, and the positive electrode film layer is laminated on any one or both of the two opposing surfaces of the positive electrode current collector.
  • the positive film layer typically includes a positive active material and optionally a binder and an optional conductive agent.
  • the positive electrode active material, optional conductive agent and optional binder are dispersed in a solvent and stirred evenly to form a positive electrode slurry, which is then dried and cold pressed to form a positive electrode film layer.
  • the solvent may be N-methylpyrrolidone (NMP).
  • the positive electrode active material may be selected from active materials known in the art that can be used for a secondary battery positive electrode.
  • the positive electrode active material may include one or more of lithium transition metal oxides and polyanion positive electrode materials.
  • lithium transition metal oxides may include lithium cobalt oxides (such as LiCoO 2 ), lithium nickel oxides (such as LiNiO 2 ), layered lithium manganese oxides (such as LiMnO 2 ), lithium nickel cobalt manganese oxides (such as LiNi a Co b Mn 1-ab O 2 ), lithium nickel cobalt aluminum oxide (such as LiNi a Co b Al 1-ab O 2 ), lithium nickel cobalt oxide (such as LiNi y Co 1-y O 2 ), layered Lithium cobalt manganese oxide (such as LiCo y Mn 1-y O 2 ), lithium cobalt aluminum oxide (such as LiCo y Al 1-y O 2 ), lithium cobalt boron oxide (such as LiCo y B 1-y O 2
  • polyanionic positive electrode materials may include lithium iron phosphate (such as LiFePO 4 ), lithium manganese phosphate (such as LiMnPO 4 ), lithium cobalt phosphate (such as LiCoPO 4 ), lithium nickel phosphate (such as LiNiPO 4 ), iron manganese phosphate Lithium (such as LiFe y Mn 1-y PO 4 ) and one or more of the above modified materials.
  • the aforementioned modification materials may be coating modification and/or doping modification.
  • a means 0 ⁇ a ⁇ 1
  • b means 0 ⁇ b ⁇ 1.
  • y independently represents 0 ⁇ y ⁇ 1.
  • the binder can stably bond the positive electrode active material and optional conductive agent to the positive electrode current collector.
  • the binder of the positive film layer can be selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride- One or more of hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and modified polymers of the above substances.
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • PTFE polytetrafluoroethylene
  • vinylidene fluoride-tetrafluoroethylene-propylene terpolymer vinylidene fluoride- One or more of hexafluoropropylene-tetrafluoroethylene
  • the conductive agent can improve the electron conduction performance of the positive electrode film layer.
  • the conductive agent of the positive film layer can be selected from one of superconducting carbon, carbon black (such as Super P, acetylene black, Ketjen black), carbon dots, carbon nanotubes, graphene and carbon nanofibers or several.
  • the positive current collector can be made of a material with good electrical conductivity and mechanical strength, which can conduct electricity and collect current.
  • a material with good electrical conductivity and mechanical strength which can conduct electricity and collect current.
  • aluminum foil, nickel foil, or a composite metal foil formed by the two can be used as the positive electrode current collector.
  • 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.
  • the negative electrode current collector has two opposing surfaces in its thickness direction, and the negative electrode film layer is laminated on any one or both of the two opposing surfaces of the negative electrode current collector.
  • the negative electrode film layer generally includes negative electrode active materials and optionally binders, optional conductive agents and other optional additives.
  • the negative electrode active material and optional conductive agent, optional binder, optional auxiliary agent, etc. are dispersed in a solvent and stirred evenly to form a negative electrode slurry, which is dried and cold pressed to form a negative electrode film layer.
  • the solvent can be N-methylpyrrolidone (NMP) or deionized water.
  • the negative electrode active material may be selected from active materials known in the art that can be used for secondary battery negative electrodes.
  • the negative electrode active material can be selected from graphitic carbon materials (such as artificial graphite, natural graphite), non-graphitic carbon materials (such as hard carbon, etc.), metallic lithium, lithium alloys (such as Li-Mg alloys, Li -Cu-Sn alloys, etc.), elemental silicon, silicon-based alloys (such as Mg-Si alloys, etc.), silicon-based oxides (such as SiO, etc.), elemental tin, tin-based alloys (such as Sn-Sb alloys, etc.), tin-based oxides (such as SnO, SnO 2 , etc.), other metal oxides (such as Li z Fe 2 O 3 , Li z WO 2 , PbO, PbO 2 , Pb 2 O 3 , Pb 3 O 4 , Sb 2 O 3 , Sb 2 O 4 , Sb 2
  • the conductive agent can improve the electron conduction performance of the negative electrode film layer.
  • the conductive agent of the negative film layer can be selected from one of superconducting carbon, carbon black (such as Super P, acetylene black, Ketjen black, etc.), carbon dots, carbon nanotubes, graphene and carbon nanofibers. species or several.
  • the binder can stably bind the negative electrode active material and the optional conductive agent to the negative electrode current collector.
  • the binder of the negative film layer can be selected from styrene-butadiene rubber (SBR), water-based acrylic resin, polyvinyl alcohol (PVA), sodium alginate (SA) and carboxymethyl chitosan (CMCS) one or more of them.
  • other optional additives are, for example, thickeners (such as sodium carboxymethylcellulose CMC-Na), PTC thermistor materials, and the like.
  • the negative electrode current collector can be made of a material with good electrical conductivity and mechanical strength, which can conduct electricity and collect current.
  • the negative electrode current collector can use copper foil, nickel foil, stainless steel sheet, titanium foil, and a metal foil formed by combining two or more of them.
  • a lithium-based metal sheet can be used as the negative electrode sheet.
  • the isolation film can be selected from any one or several isolation films in this application.
  • the separator described in this application and other separators known in the art can be selected for use in an electrochemical device.
  • An electrochemical device includes the separator of the present application, and thus can have the same or similar beneficial effects.
  • the present application has no specific limitation on the type of electrolyte, which can be selected according to requirements.
  • the electrolyte may be selected from solid electrolytes (eg, inorganic solid electrolytes, polymer solid electrolytes, organic-inorganic composite solid electrolytes), or liquid electrolytes (ie, electrolytic solutions).
  • the electrolyte is selected from electrolytic solutions.
  • the electrolytic solution includes electrolyte salts and solvents.
  • Electrolyte salts can dissociate into anions and cations in a solvent.
  • the cations may include one or more of lithium ions, sodium ions, potassium ions, and magnesium ions.
  • Anions may include PF 6 - , BF 4 - , Cl - , Br - , I - , ClO 4 - , AsF 6 - , bisfluorosulfonyl imide anion N(SO 2 F) 2 - , bistrifluoromethanesulfonyl Imine anion N(CF 3 SO 2 ) 2 - , acetate anion CH 3 CO 2 - , trifluoromethanesulfonic acid CF 3 SO 3 - , difluorooxalate borate anion (structural formula A1), dioxalate borate anion (structural formula A2 ), difluorophosphate ion PO 2 F 2 - , difluorodifluorooxalatephosphate
  • the electrolyte salt may be selected from lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium perchlorate (LiClO 4 ), lithium hexafluoroarsenate (LiAsF 6 ), difluorosulfonyl Lithium amide (LiFSI), lithium bistrifluoromethanesulfonyl imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium difluorooxalate borate (LiBOB), lithium difluorophosphate (LiPO 2 F 2 ), lithium difluorooxalate phosphate (LiDFOP) and lithium tetrafluorooxalate phosphate (LiTFOP).
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium perchlorate
  • the solvent an organic solvent can be used.
  • the solvent may be selected from ethylene carbonate (EC), propylene carbonate (PC), ethylmethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), Dipropyl Carbonate (DPC), Methyl Propyl Carbonate (MPC), Ethyl Propyl Carbonate (EPC), Butylene Carbonate (BC), Fluoroethylene Carbonate (FEC), Methyl Formate (MF), Methyl Acetate Ester (MA), Ethyl Acetate (EA), Propyl Acetate (PA), Methyl Propionate (MP), Ethyl Propionate (EP), Propyl Propionate (PP), Methyl Butyrate (MB) , ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone
  • additives are optionally included in the electrolyte.
  • additives can include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain performances of batteries, such as additives that improve battery overcharge performance, additives that improve battery high-temperature performance, and additives that improve battery low-temperature performance. Additives etc.
  • the positive pole piece, the negative pole piece and the separator can be made into an electrode assembly through a lamination process or a winding process, so that the separator is placed between the positive pole piece and the negative pole piece for isolation; the electrode assembly is placed in the outer packaging , inject electrolyte and seal to obtain a secondary battery.
  • the separator in the electrode assembly includes at least one or more separators as described in this application.
  • the outer package of the secondary battery is used to encapsulate the electrode assembly and the electrolyte.
  • the outer packaging of the secondary battery may be a hard case, such as a hard plastic case, aluminum case, steel case, and the like.
  • 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 can be plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), etc. can be included.
  • FIG. 4 shows a secondary battery 5 with a square structure as an example.
  • the outer package may include a housing 51 and a cover 53 .
  • the casing 51 may include a bottom plate and a side plate connected to the bottom plate, the bottom plate and the side plates enclose an accommodating cavity.
  • the housing 51 has an opening communicating with the accommodating cavity, and the cover plate 53 can cover the opening to close the accommodating cavity.
  • the electrode assembly 52 is packaged in the containing cavity. Electrolyte is infiltrated in the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the secondary battery 5 can be one or several, and can be adjusted according to requirements.
  • Electrochemical devices include any one or several electrochemical devices of the present application. Therefore, electrochemical devices also have the same or similar beneficial effects as electrochemical devices, such as higher safety performance.
  • an electrochemical device may include a plurality of electrochemical devices.
  • the specific number of electrochemical devices contained in the electrochemical device can be adjusted according to the application and capacity of the electrochemical device. And according to different application requirements, multiple electrochemical devices can be connected in series, in parallel, or in a combination of series and parallel.
  • the electrochemical device may be a battery pack.
  • battery packs include battery modules, battery packs, and the like.
  • a battery module may be assembled from a plurality of secondary batteries. The specific number of secondary batteries included in the battery module can be adjusted according to the application and capacity of the battery module.
  • a battery pack may be assembled from a plurality of secondary batteries or a plurality of battery modules. The number of secondary batteries or battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.
  • FIG. 6 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 may be fixed by fasteners.
  • the battery module 4 may also include a case with a containing space to accommodate a plurality of secondary batteries 5 .
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box.
  • the battery box includes an upper box body 2 and a lower box body 3 , the upper box body 2 can cover the lower box body 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 electrochemical device or electrochemical device described in the present application.
  • the electrochemical device or electrochemical device can be used as a power source of the electrical device, and can also be used as an energy storage unit of the electrical device.
  • the electric device may include at least one of the secondary battery, battery module, or battery pack described in this application. It can be selected according to the actual usage requirements of the electrical device.
  • the electric devices may include mobile devices (such as mobile phones, notebook computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, etc.) , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but not limited thereto.
  • mobile devices such as mobile phones, notebook computers, etc.
  • electric vehicles such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, etc.
  • electric trucks, etc. electric trains, ships and satellites, energy storage systems, etc., but not limited thereto.
  • FIG. 9 is an example of an electrical device.
  • the device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • the electric device can use a battery pack or a battery module as a power source.
  • the electric device may be a mobile phone, a tablet computer, a notebook computer, and the like.
  • the electrical device can use a secondary battery as a power source.
  • the weight average molecular weight is 2,000,000 and the crystallinity is 53% PE (ie the first polyethylene), the weight average molecular weight is 600,000 and the crystallinity is 50% PE (ie the second polyethylene) and Paraffin oil is mixed according to the weight ratio of 2:1:7, extruded, extruded sheet-like film through T-die at high temperature, cast to cooling roll at 20°C to cool; stretched in MD direction, and then stretched in TD direction; extraction Remove the paraffin oil; then heat-set and cut to make the base film.
  • PE ie the first polyethylene
  • the weight average molecular weight is 600,000
  • the crystallinity is 50% PE (ie the second polyethylene)
  • Paraffin oil is mixed according to the weight ratio of 2:1:7, extruded, extruded sheet-like film through T-die at high temperature, cast to cooling roll at 20°C to cool; stretched in MD direction, and then stretched in TD direction; extraction Remove the paraffin oil; then heat-set and cut to make
  • the stretching ratio in the MD direction is 4, and the stretching temperature is 114°C; the thickness of the sheet after stretching in the MD direction is 0.3mm; the stretching ratio in the TD direction is 4.4, and the stretching temperature is 116°C; the heat setting temperature is 135°C.
  • the force value F M of the obtained base film at the time of tensile fracture in the MD direction is 17.79N
  • the tensile displacement ⁇ L M at the time of tensile fracture in the MD direction is 98mm
  • the tensile energy C M per unit thickness in the MD direction is 2.49J/10 ⁇ m
  • the elongation ⁇ M in the MD direction was 245%.
  • the force value F T of the obtained base film at the time of tensile fracture in the TD direction is 16.13N
  • the tensile displacement ⁇ L T at the time of tensile fracture in the TD direction is 78mm
  • the tensile energy CT per unit thickness in the TD direction is 1.8J/10 ⁇ m
  • the elongation ⁇ T in the TD direction was 195%.
  • the porosity of the base film was 30%.
  • the thickness d of the base film was 7 ⁇ m.
  • Preparation of the heat-resistant layer Add 97 parts by weight of alumina particles and 3 parts by weight of polyacrylate binder into deionized water, mix them uniformly to make a slurry; then use the micro-gravure coating method to evenly coat the slurry Spread it on any surface of the base film in its own thickness direction; after drying in an oven, a heat-resistant layer is obtained.
  • the thickness of the heat-resistant layer was 3 ⁇ m.
  • positive electrode active material lithium cobalt oxide also known as lithium cobaltate
  • conductive carbon 3 parts by weight
  • binder PVDF 3 parts by weight
  • the above-mentioned positive electrode piece, separator, and negative electrode piece are stacked in order, so that the separator is between the positive and negative electrode pieces to play an isolation role, and the bare cell is obtained by winding. Put the bare cell in the outer package, inject electrolyte, package and form, and then make a lithium-ion secondary battery.
  • Examples 2-6 and Comparative Examples 1-2 The preparation method is similar to that of Example 1, the difference is that the relevant parameters in the preparation steps of the separator are adjusted, see Table 1 for details.
  • the weight ratio is the weight of the first polyethylene: the weight of the second polyethylene: the weight of the pore-forming agent paraffin oil.
  • Examples 7-28 The preparation method is similar to that of Example 3, the difference is that the relevant parameters in the preparation step of the heat-resistant layer of the isolation film are adjusted, see Table 4 for details.
  • Comparative Examples 3-7 The preparation method is similar to that of Comparative Example 1, the difference is that the relevant parameters in the preparation step of the heat-resistant layer of the isolation film are adjusted, see Table 4 for details.
  • Secondary batteries with K>0.08 are recorded as unqualified self-discharge products.
  • the self-discharge failure ratio is calculated by the ratio of the number of self-discharge failures to the total number of samples. The lower the unqualified ratio of the self-discharge of the secondary battery, the higher the performance of the isolation film against penetration by foreign particles.
  • the base film has higher tensile energy per unit thickness in the MD direction and higher tensile energy per unit thickness in the TD direction, and the extension of the base film in the MD direction and the TD direction The rate is high, so the shrinkage rate and hole expansion rate of the separator are low at high temperature, so that it can play a good role in isolating the positive and negative electrodes and improve the safety performance of the battery.
  • the separator of the embodiment of the present application since the base film has higher tensile energy per unit thickness in the MD direction and higher tensile energy per unit thickness in the TD direction, and the extension of the base film in the MD direction and TD direction The rate is high, so the separator can effectively inhibit the penetration of particles, especially in extreme cases such as acupuncture, the damage area of the separator is small, thus reducing the risk of thermal runaway of the battery. Therefore, the secondary battery adopting the separation film of the present application can simultaneously take into account a lower proportion of self-discharge defective products and a higher pass rate of the acupuncture test, thereby obtaining higher safety performance.
  • the separators of Comparative Example 1 and Comparative Example 2 have low tensile energy per unit thickness in the MD direction and low tensile energy per unit thickness in the TD direction, and the elongation of the base film in the MD direction and TD direction is small, so the safety of the battery using it is relatively low. Performance is poor.
  • the thickness of the heat-resistant layer in Table 4 refers to the thickness of the heat-resistant layer on one side.
  • the thickness of the heat-resistant layer on each side surface is equal.
  • the thickness of the heat-resistant layer is within an appropriate range, which can further reduce the heat of the isolation film under the premise of ensuring that the isolation film has a smaller thickness. Shrinkage rate and pinhole expansion rate, and further reduce the self-discharge probability of the battery and improve the safety performance of acupuncture.
  • the heat-resistant layer has an appropriate proportion of heat-resistant particles, which helps to further reduce the thermal shrinkage rate and pinhole expansion rate of the separator , and further reduce the self-discharge probability of the battery and improve the safety performance of acupuncture.
  • the performance of the separator that satisfies the tensile energy per unit thickness in the MD direction and the tensile energy per unit thickness in the TD direction of the base film and the elongation in the MD direction and TD direction of the base film is better, and the safety of the secondary battery using it is better. Higher performance.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Ceramic Engineering (AREA)
  • Composite Materials (AREA)
  • Cell Separators (AREA)

Abstract

本申请提供一种隔离膜及其制备方法、电化学装置、电化学设备和用电装置。隔离膜包括基膜，所述基膜在MD方向和TD方向的单位厚度拉伸能量均≥1.8J/10μm，且所述基膜在MD方向和TD方向的延伸率均≥150％；所述基膜的厚度为2μm～40μm。

Description

隔离膜及其制备方法、电化学装置、电化学设备和用电装置 技术领域
本申请属于储能装置技术领域，具体涉及一种隔离膜及其制备方法、电化学装置、电化学设备和用电装置。
背景技术
近年来，以二次电池为代表的电化学装置在各类电子产品和新能源汽车等产业得到广泛应用及推广。同时，人们对电化学装置的能量密度也提出了更高的要求。作为提高电化学装置能量密度的一个方向，是对电化学装置中的部件进行降低重量或减小体积。例如，在二次电池中通常会设置隔离膜，可以通过减薄隔离膜的厚度，减小二次电池重量和体积，以期望提升二次电池的能量密度。隔离膜为微孔性的多孔薄膜，其用来隔离正极极片和负极极片，防止电池内部正、负极极片之间发生短路，同时可以使活性离子通过，并且还具有保持电解液的功能。但是，隔离膜的厚度较小，导致二次电池的内短路风险增加，由此使二次电池的安全性能受到极大的挑战。
发明内容
本申请第一方面提供一种隔离膜，包括基膜，所述基膜在纵向(Machine Direction，简写为MD)方向和横向(Transverse Direction，简写为TD)方向的单位厚度拉伸能量均≥1.8J/10μm，且所述基膜在MD方向和TD方向的延伸率均≥150％；
其中，所述单位厚度拉伸能量为
Figure PCTCN2021109904-appb-000001
F表示所述基膜的标距长度为40mm且宽度为15mm的试样以50mm/min的恒速拉伸至断裂时的以N计的力值，ΔL表示所述拉伸断裂时的以m计的拉伸位移，d表示所述试样的以μm计的初始厚度；
所述基膜的厚度为2μm～40μm。
本申请提供的隔离膜中，由于具有较小厚度的基膜还满足在MD方向的单位厚度拉伸能量和延伸率在适当范围内，以及在TD方向的单位厚度拉伸能量和延伸率在适当范围内，因而能具有较高的韧性和强度。因此，隔离膜能有效抑制异物颗粒的刺穿，极大的降低了诸如二次电池等使用隔离膜的电化学装置发生短路失效的风险。特别地，隔离膜还能具有较高的耐热性，其在受热条件下的收缩率较小，并且受破坏形成的孔在受热条件下的扩孔率较低。因此，采用该隔离膜的电化学装置即使在受到穿钉等机械破坏时，由于隔离膜仍能起到良好的隔离作用，从而能降低电化学装置发生热失控的风险。因此， 电化学装置能具有较高的安全性能。
在本申请的任一实施方式中，基膜在MD方向的单位厚度拉伸能量为1.8J/10μm～50J/10μm，可选为2.4J/10μm～50J/10μm，进一步可选地为2.7J/10μm～30J/10μm。基膜在MD方向的单位厚度拉伸能量在适当范围内，能进一步改善隔离膜的耐异物颗粒刺穿能力，并且减小隔离膜受到破坏时的破裂面积，从而改善电化学装置的安全性能。
在本申请的任一实施方式中，基膜在TD方向的单位厚度拉伸能量为1.8J/10μm～50J/10μm，可选为2J/10μm～50J/10μm，进一步可选地为2.5J/10μm～30J/10μm。基膜在TD方向的单位厚度拉伸能量在适当范围内，能进一步改善隔离膜的耐异物颗粒刺穿能力，并且减小隔离膜受到破坏时的破裂面积，从而改善电化学装置的安全性能。
在本申请的任一实施方式中，基膜在MD方向的延伸率为150％～4000％，可选地为180％～4000％，进一步可选地为200％～2000％。基膜在MD方向的延伸率在适当范围内，使得隔离膜的耐异物刺穿能力较强。即使在电化学装置受到机械破坏时，隔离膜的破裂面积也比较小，因此能降低机械破坏带来的危害。因此，电化学装置的安全性能可得到提升。
在本申请的任一实施方式中，基膜在TD方向的延伸率为150％～4000％，可选地为180％～4000％，进一步可选地为200％～2000％。基膜在TD方向的延伸率在适当范围内，使得隔离膜的耐异物刺穿能力较强。即使在电化学装置受到机械破坏时，隔离膜的破裂面积也比较小，因此能降低机械破坏带来的危害。因此，电化学装置的安全性能可得到提升。
在本申请的任一实施方式中，基膜的厚度可选为2μm～20μm，还可选为3μm～15μm，还可选为3μm～10μm。基膜具有适当的厚度，既能使隔离膜具有较好的抵抗异物颗粒刺穿能力，还有助于降低电化学装置的体积和重量。因此，电化学装置能具有较高的安全性能和能量密度。
在本申请的任一实施方式中，基膜为聚合物基膜，基于所述基膜的配料中聚合物的总质量，所述基膜中聚乙烯类聚合物的质量占比为50％以上，可选地为80％以上，进一步可选地为100％。所述聚乙烯类聚合物包括聚乙烯、乙烯与α-烯烃的共聚物中的一种或几种，可选地，所述α-烯烃选自丙烯、1-丁烯、1-辛烯中的一种或几种。以聚乙烯类聚合物为主要聚合物组成得到的基膜能具有良好的强度和韧性，因此能使隔离膜具有较高的抵抗异物颗粒刺穿能力，进而改善电化学装置的安全性能。
在本申请的任一实施方式中，基膜包含两种以上的聚乙烯类聚合物，其中满足：1＜M1/M2≤50，可选地，2≤M1/M2≤30，进一步可选地，3≤M1/M2≤10。M1表示所述基膜的配料中具有最大重均分子量的聚乙烯类聚合物的重均分子量，M2表示所述基膜的配料中具有最小重均分子量的聚乙烯类聚合物的重均分子量。通过使用不同聚乙烯类聚合物进行合理匹配，能使隔离膜各处的抵抗异物颗粒刺穿能力均较高，并且隔离膜还能具有较高的耐热性能。因此，隔离膜能在电化学装置中充分有效地发挥隔离正、负极的作用，进一步提高电化学装置的安全性能。
在本申请的任一实施方式中，M1为110万～500万，可选地为150万～300万。
在本申请的任一实施方式中，M2为10万～100万，可选地为30万～100万。
在本申请的任一实施方式中，基于所述基膜的配料中聚合物的总质量，所述基膜中所述具有最大重均分子量的聚乙烯类聚合物的质量占比为10％～100％，可选地为10％～90％，进一步可选地为30％～70％。这样有助于提高隔离膜的耐穿刺强度。
在本申请的任一实施方式中，基于所述基膜的配料中聚合物的总质量，所述基膜中所述具有最小重均分子量的聚乙烯类聚合物的质量占比为0～90％，可选地为10％～90％，进一步可选地为30％～70％。这样有助于隔离膜获得较高的韧性。因此，隔离膜的抵抗异物刺穿能力较强，并且在受到穿刺等极端机械破坏时的破裂面积较小。
在本申请的任一实施方式中，聚乙烯类聚合物的结晶度≤65％，可选地为≤50％，进一步可选地为≤45％。聚乙烯类聚合物的结晶度在适当范围内，能使隔离膜具有高延展性。因此，隔离膜的抵抗异物颗粒刺穿能力较高，从而能改善电化学装置的安全性能。
在本申请的任一实施方式中，还包括耐热层，所述耐热层位于所述基膜的至少一个表面。耐热层能改善隔离膜的耐热性。当电化学装置被刺穿发生短路时，能有效抑制隔离膜被短路产生的热量熔融，防止短路点面积进一步扩大，因而进一步降低电化学装置的热失控风险。
在本申请的任一实施方式中，耐热层包含耐热颗粒，所述耐热颗粒在耐热层中的质量占比≥40％，可选地为40％～99％，还可选地为80％～97％。耐热层中含有适量的耐热颗粒，能进一步提高隔离膜的抵抗异物颗粒刺穿能力和耐热性，因而能进一步改善电化学装置的安全性能。
在本申请的任一实施方式中，耐热颗粒可包括无机耐热颗粒、有机耐热颗粒中的一种或几种。在一些实施例中，无机耐热颗粒可选自氧化铝、氧化硅、氧化钛、碳酸钙、氧化镁、氢氧化镁、勃姆石、钛酸钡、硫酸钡中的一种或几种。在一些实施例中，有机耐热颗粒可选自聚丙烯酸树脂、芳纶、聚苯硫醚、聚甲基丙烯酸甲酯、聚偏氟乙烯、聚四氟乙烯、聚偏氟乙烯-六氟丙烯共聚物中的一种或几种。
在本申请的任一实施方式中，耐热层的厚度≥0.1mm，可选地为0.1mm～10mm，还可选地为1mm～3mm。耐热层的厚度满足上述条件，能有效地改善隔离膜的抵抗异物颗粒刺穿能力和耐热性。
在本申请的任一实施方式中，耐热层与所述基膜之间的剥离强度≥10N/m，可选地为15N/m～200N/m，进一步可选地为20N/m～200N/m。隔离膜的层间粘结性较好，能使隔离膜的抵抗异物颗粒刺穿能力和耐热性能得到改善。
在本申请的任一实施方式中，隔离膜满足：(l M0-l M)/l M0×100％≤30％，可选地，(l M0-l M)/l M0×100％≤10％，进一步可选地，(l M0-l M)/l M0×100％≤5％，其中l M表示所述隔离膜的MD方向长度l M0为100mm且TD方向长度l T0为100mm的试样于130℃保持1h后的以mm计的MD方向长度。
在本申请的任一实施方式中，隔离膜满足：(l T0-l T)/l T0×100％≤30％，可选地，(l T0-l T)/l T0×100％≤10％，进一步可选地，(l T0-l T)/l T0×100％≤5％，其中l T表示所述隔离膜的MD方向长度l M0为100mm且TD方向长度l T0为100mm的试样于130℃保持1h后的以mm计的TD方向长度。
隔离膜在受热条件的收缩率较小，有助于进一步改善电化学装置的安全性能。
在本申请的任一实施方式中，隔离膜被横截面积为0.5mm 2的针刺穿，并在150℃下保持10min后，针孔的扩孔率≤8％，可选地为≤5％，进一步可选地为≤4％，更进一步可选地为≤3％。所述扩孔率为(S 1-S 0)/S 0×100％，S 0表示针孔的初始面积，S 1表示在150℃下保持10min后的针孔面积。隔离膜被针刺穿后，在受热条件下的针孔扩孔率较小，则其耐热性较高，特别是较小的破裂面积能降低电化学装置发生热失控的风险。
本申请第二方面提供一种隔离膜的制备方法，包括：
(a)提供包含聚合物和成孔剂的熔融态基膜配料；
(b)将基膜配料挤出并冷却形成片材；
(c)对片材进行MD方向拉伸；
(d)对片材进行TD方向拉伸；
(e)去除片材中的成孔剂，形成多孔片材；
(f)将多孔片材进行热定型，得到基膜；
其中，所述基膜用作隔离膜，或所述基膜进行后处理后用作隔离膜；
所述基膜在纵向MD方向和横向TD方向的单位厚度拉伸能量均≥1.8J/10μm，且所述基膜在MD方向和TD方向的延伸率均≥150％；所述基膜的厚度为2μm～40μm。
根据本申请的制备方法得到的基膜的厚度较小，同时还具有适当的MD方向的单位厚度拉伸能量和延伸率，以及适当的TD方向的单位厚度拉伸能量和延伸率，因而能获得较高的韧性和强度。采用该隔离膜的电化学装置能具有较高的安全性能。
在本申请的任一实施方式中，所述基膜进行后处理可包括：(g)在基膜的至少一个表面形成耐热层。由此得到包含基膜和位于基膜表面的耐热层的隔离膜。
在本申请的任一实施方式中，步骤(b)所述冷却的温度为15℃～30℃，可选地为20℃～25℃。
在本申请的任一实施方式中，步骤(c)所述MD方向拉伸的拉伸倍率为3～6倍，可选地为3～5倍，还可选为3～4.5倍。
在本申请的任一实施方式中，步骤(d)所述TD方向拉伸的拉伸倍率为3～6倍，可选地为3～5倍，还可选为3.5～5倍。
在本申请的任一实施方式中，步骤(f)所述热定型包括在130℃以上的温度下对所述多孔片材进行热定型。可选的温度为130℃～150℃，还可选为134℃～145℃。
本申请第三方面提供一种电化学装置，其包括根据本申请的隔离膜。本申请的电化学装置由于采用本申请的隔离膜，因而能获得较高的安全性能。
本申请第四方面提供一种电化学设备，其包括根据本申请的电化学装置。本申请的电化学设备包括本申请所述电化学装置，因而具有较高的安全性能。
本申请第五方面提供一种用电装置，其包括根据本申请的电化学装置或电化学设备中的至少一种。本申请的用电装置包括本申请所述电化学装置或电化学设备，因而具有较高的安全性能。
附图说明
图1是本申请一个实施例提供的隔离膜的断面的放大倍数为5000倍的扫描电镜 (SEM)图。
图2是本申请一个实施例提供的隔离膜的基膜在5000倍数下的SEM图。
图3是图2所示基膜在20000倍数下的SEM图。
图4是二次电池的一实施方式的示意图。
图5是图4的分解图。
图6是电池模块的一实施方式的示意图。
图7是电池包的一实施方式的示意图。
图8是图7的分解图。
图9是二次电池用作电源的装置的一实施方式的示意图。
具体实施方式
以下，适当地参照附图详细说明具体公开了本申请的隔离膜及其制备方法与包含该隔离膜的电化学装置、电化学设备和用电装置的实施方式。但是会有省略不必要的详细说明的情况。例如，有省略对已众所周知的事项的详细说明、实际相同结构的重复说明的情况。这是为了避免以下的说明不必要地变得冗长，便于本领域技术人员的理解。此外，附图及以下说明是为了本领域技术人员充分理解本申请而提供的，并不旨在限定权利要求书所记载的主题。
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60～120和80～110的范围，理解为60～110和80～120的范围也是预料到的。此外，如果列出的最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1～3、1～4、1～5、2～3、2～4和2～5。在本申请中，除非有其他说明，数值范围“a～b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0～5”表示本文中已经全部列出了“0～5”之间的全部实数，“0～5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有步骤可以顺序进行，也可以随机进行，优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，所述提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。
如果没有特别的说明，本申请所提到的“包括”和“包含”表示开放式，也可以 是封闭式。例如，所述“包括”和“包含”可以表示还可以包括或包含没有列出的其他组分，也可以仅包括或包含列出的组分。
如果没有特别的说明，在本申请中，术语“或”是包括性的。举例来说，短语“A或B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B都为真(或存在)。
如果没有特别的说明，本申请所提到的“以上”、“以下”为包含本数，“几种(个)”表示两种(个)或两种(个)以上。
本申请提供一种隔离膜，该隔离膜包括基膜，所述基膜在MD方向和TD方向的单位厚度拉伸能量均≥1.8J/10μm，且所述基膜在MD方向和TD方向的延伸率均≥150％，且所述基膜的厚度为2μm～40μm。
所述单位厚度拉伸能量为
Figure PCTCN2021109904-appb-000002
F表示所述基膜的标距长度为40mm且宽度为15mm的试样以50mm/min的恒速拉伸至断裂时的以N计的力值，ΔL表示所述拉伸断裂时的以m计的拉伸位移，d表示所述试样的以μm计的初始厚度。
为了使测试结果更精确，可以沿基膜的MD方向取5片长100mm且宽15mm的试样，其中试样的长度方向与基膜的MD方向平行；分别将各试样夹持在拉力机相对的两个夹具中，设置试样标距长度为40mm(即夹具之间的距离)，以50mm/min恒速进行拉伸测试。读取试样拉伸断裂时的力值F和拉伸位移ΔL。根据单位厚度拉伸能量计算公式计算各试样的单位厚度拉伸能量，取平均值作为基膜在MD方向的单位厚度拉伸能量。根据延伸率＝ΔL/0.1×100％计算各试样的延伸率，取平均值作为基膜在MD方向的延伸率。参照上述方法测试基膜在TD方向的单位厚度拉伸能量和延伸率。以上测试均在室温、常压下进行。测试可采用高铁检测仪器公司的拉力机，例如AI-3000-S型。测试可参考国标GB/T 36363-2018。
由于厚度较小的基膜满足在MD方向的单位厚度拉伸能量和延伸率在适当范围内，以及在TD方向的单位厚度拉伸能量和延伸率在适当范围内，因而能使隔离膜具有较高的韧性和强度。因此，隔离膜能有效抑制异物颗粒的刺穿，极大的降低了诸如二次电池等使用隔离膜的电化学装置发生短路而造成自放电，甚至导致热失控的风险。特别地，该隔离膜还能具有较高的耐热性，其在受热条件下的收缩率较小，并且受破坏形成的孔在受热条件下的扩孔率较低。因此，采用该隔离膜的电化学装置在受到穿钉等机械破坏时，由于隔离膜仍能起到良好的隔离作用，从而能降低电化学装置发生起火、爆炸的风险。因此，该电化学装置能具有较高的安全性能。
在一些实施方式中，基膜在MD方向的单位厚度拉伸能量为1.8J/10μm～100J/10μm，可选地为1.8J/10μm～50J/10μm，2.4J/10μm～50J/10μm，2.7J/10μm～50J/10μm，2.8J/10μm～50J/10μm，2.5J/10μm～45J/10μm，或2.7J/10μm～30J/10μm。基膜在MD方向的单位厚度拉伸能量在适当范围内，使得隔离膜的MD方向机械强度较高，因此隔离膜的耐异物颗粒刺穿能力较高。同时，隔离膜在MD方向还具有适当柔韧性，由此在电化学装置受到机械破坏时，隔离膜的破裂面积较小，从而能降低机械破坏带来的危害，甚至还可 以使电化学装置在短时间内正常工作。
在一些实施方式中，基膜在TD方向的单位厚度拉伸能量为1.8J/10μm～100J/10μm，可选地为1.8J/10μm～50J/10μm，2J/10μm～50J/10μm，2.4J/10μm～50J/10μm，2.8J/10μm～50J/10μm，2J/10μm～45J/10μm，或2.5J/10μm～30J/10μm。基膜在TD方向的单位厚度拉伸能量在适当范围内，使得隔离膜的TD方向机械强度较高，因此隔离膜的耐异物颗粒刺穿能力较高。同时，隔离膜在TD方向还具有适当柔韧性，由此在电化学装置受到机械破坏时，隔离膜的破裂面积较小，从而能降低机械破坏带来的危害，甚至还可以使电化学装置在短时间内正常工作。
在一些实施方式中，基膜在MD方向的延伸率为150％～4000％，可选地为180％～4000％，180％～3000％，200％～3000％，250％～3000％，200％～2000％，或250％～2000％。基膜在MD方向的延伸率在适当范围内，使得隔离膜在MD方向的柔韧性较好，并且机械强度较高。因此，隔离膜的耐异物刺穿能力较强。即使在电化学装置受到机械破坏时，隔离膜的破裂面积也比较小，因此能降低机械破坏带来的危害，甚至还可以使电化学装置在短时间内正常工作。
在一些实施方式中，基膜在TD方向的延伸率为150％～4000％，可选地为180％～4000％，180％～3000％，200％～3000％，250％～3000％，200％～2000％，或250％～2000％。基膜在TD方向的延伸率在适当范围内，使得隔离膜在TD方向的柔韧性较好，并且机械强度较高。因此，隔离膜的抵抗异物刺穿能力较强。即使在电化学装置受到机械破坏时，隔离膜的破裂面积也比较小，因此能降低机械破坏带来的危害，甚至还可以使电化学装置在短时间内正常工作。
在一些实施方式中，基膜的厚度为2μm～30μm，可选地为2μm～20μm，3μm～15μm，3μm～10μm，7μm～12μm，5μm～10μm，或2μm～9μm。基膜具有适当的厚度，既能使隔离膜具有较好的抵抗异物颗粒刺穿能力，以便有效地起到隔离正、负极极片的作用，还有助于降低电化学装置的体积和重量。因此，电化学装置能具有较高的安全性能和能量密度。
在一些实施方式中，基膜为聚合物基膜。基膜的配料中，聚合物以聚乙烯类聚合物为主。在一些实施例中，基于基膜的配料中聚合物的总质量，基膜中聚乙烯类聚合物的质量占比为50％以上，可选地为80％以上，进一步可选地为100％。聚乙烯类聚合物包括聚乙烯(PE)、乙烯与α-烯烃的共聚物中的一种或几种。α-烯烃可选自碳原子数为3～10的α-烯烃。可选地，α-烯烃选自丙烯、1-丁烯、1-辛烯中的一种或几种。乙烯与α-烯烃的共聚物的具体示例可包括聚乙烯-丙烯共聚物、聚乙烯-丁烯共聚物、聚乙烯-丙烯-丁烯共聚物、聚乙烯-辛烯共聚物中的一种或几种。以聚乙烯类聚合物为主要聚合物组成得到的基膜能具有良好的强度和韧性，因此能使隔离膜具有较高的抵抗异物颗粒刺穿能力，进而改善电化学装置的安全性能。
本申请所述的共聚物可以为无规共聚物。术语“无规”表示共聚单体在共聚物的分子链上无规排列(即呈随机分布)。
在一些实施方式中，基膜可包含两种以上的聚乙烯类聚合物，其中满足：1＜M1/M2≤50；可选地，1.2≤M1/M2≤30，2≤M1/M2≤30，2≤M1/M2≤10，3≤M1/M2 ≤10，或3≤M1/M2≤6。M1表示基膜的配料中具有最大重均分子量的聚乙烯类聚合物的重均分子量，M2表示基膜的配料中具有最小重均分子量的聚乙烯类聚合物的重均分子量。基膜采用两种以上的聚乙烯类聚合物，且该两种以上聚乙烯类聚合物的分子量之间满足适当关系，能使隔离膜整体具有较好的均匀一致性。因此，隔离膜各处的抵抗异物颗粒刺穿能力均较高，从而更好地改善电化学装置的安全性能。并且，隔离膜还能具有较高的耐热性能，其刺穿后在受热条件下的扩孔率较小。因此，隔离膜能在电化学装置中充分有效地发挥隔离正、负极的作用，进一步提高电化学装置的安全性能。
在一些实施方式中，基于基膜的配料中聚合物的总质量，基膜中具有最大重均分子量的聚乙烯类聚合物的质量占比W1为10％～100％。在一些实施例中，W1＜100％，可选地，W1为10％～90％，20％～80％，30％～70％，25％～60％，或30％～50％。W1在适当范围内，有助于提高隔离膜的耐穿刺强度。
在一些实施方式中，基于基膜的配料中聚合物的总质量，基膜中所述具有最小重均分子量的聚乙烯类聚合物的质量占比W2为0～90％。在一些实施例中，W2＞0，可选地，W2为10％～90％，20％～80％，30％～70％，40％～75％，或50％～70％。W2在适当范围内，有助于隔离膜获得较高的韧性。因此，隔离膜的抵抗异物刺穿能力较强，并且在受到穿刺等极端机械破坏时的破裂面积较小。
在一些实施方式中，M1可选为110万～500万，还可选为150万～300万，或150万～250万。在一些实施方式中，M2可选为10万～100万，还可选为30万～100万，或40万～80万。聚乙烯类聚合物具有适当的分子量，能改善基膜的韧性和强度，因此能提高隔离膜的抵抗异物颗粒刺穿能力，有效减少隔膜被刺穿的风险，从而大幅度降低了因隔膜被刺穿带来的电池热失控的潜在可能。
在一些实施方式中，聚乙烯类聚合物的结晶度≤65％，可选地为≤60％，≤55％，≤50％，或≤45％。聚乙烯类聚合物的结晶度较低，所得到的隔离膜的取向度较小，这有利于提高隔离膜的延伸率，使隔离膜具有高延展性。因此，隔离膜的抵抗异物颗粒刺穿能力较高，进一步改善电化学装置的安全性能。在一些实施例中，聚乙烯类聚合物的结晶度≥20％，≥25％，≥30％，≥35％，≥40％，或≥45％。聚乙烯类聚合物的结晶度在所给范围内，能使隔离膜具有较高的强度。
在一些实施方式中，除了聚乙烯类聚合物，基膜还可选地采用本领域已知的其他聚合物。其他聚合物的示例可包括除聚乙烯类聚合物之外的聚烯烃(如聚丙烯、聚丁烯等)、聚酰亚胺(如均苯型聚酰亚胺、聚酰胺-酰亚胺和聚醚酰亚胺等)、聚酰胺(如芳纶等)、聚酯(如聚对苯二甲酸乙二醇酯、聚对苯二甲酸丙二醇酯、聚对苯二甲酸丁二醇酯等)、聚氨酯、聚碳酸酯、聚缩醛、聚醚醚酮、聚苯硫醚、含氟聚合物(如聚偏氟乙烯PVDF、聚偏氟乙烯-六氟丙烯共聚物PVDF-HFP、聚四氟乙烯PTFE等)中的一种或几种。
基膜为微孔性多孔薄膜。在一些实施方式中，基膜的孔隙率为20％～80％，可选地为20％～40％，进一步可选地为25％～38％。基膜的孔隙率在适当范围内，有助于隔离膜具有适当的电解液保持量，由此能使电化学装置同时兼顾较高的循环性能和能量密度。
在一些实施方式中，基膜的透气值30s/100cc～300s/100cc，可选地为50s/100cc～ 250s/100cc，进一步可选地为80s/100cc～200s/100cc。基膜的透气值在适当范围内，则便于离子通过隔离膜，从而有助于电化学装置具有较高的容量性能和循环性能。
在一些实施方式中，隔离膜还包括耐热层。耐热层可位于基膜的至少一个表面。作为示例，基膜具有在自身厚度方向相对的两个表面，耐热层可位于该两个表面中的任意一者或两者。
耐热层包含耐热颗粒。颗粒与颗粒之间可形成离子穿过孔道。耐热颗粒可包括无机耐热颗粒、有机耐热颗粒中的一种或几种。作为示例，无机耐热颗粒可选自氧化铝、氧化硅、氧化钛、碳酸钙、氧化镁、氢氧化镁、勃姆石、钛酸钡、硫酸钡中的一种或几种。作为示例，有机耐热颗粒可选自聚丙烯酸树脂、芳纶、聚苯硫醚、聚甲基丙烯酸甲酯、聚偏氟乙烯、聚四氟乙烯、聚偏氟乙烯-六氟丙烯共聚物中的一种或几种。在一些实施例中，耐热颗粒包括无机耐热颗粒。
耐热层能提高隔离膜的强度，因而能进一步增强隔离膜的抵抗异物颗粒刺穿能力。尤其是，耐热层能改善隔离膜的耐热性。当电化学装置在异常情况下发生隔离膜被刺穿导致短路时，由于隔离膜的耐热性较好，能有效抑制隔离膜被短路产生的热量熔融而造成的短路点面积进一步扩大，因而进一步降低了电化学装置发生热失控或短路失效风险。
在一些实施方式中，耐热颗粒在耐热层中的质量占比≥40％，可选地为40％～99％，60％～99％，80％～99％，80％～97％，80％～95％，80％～90％，90％～97％，或85％～95％。耐热层中含有适量的耐热颗粒，能进一步提高隔离膜的抵抗异物颗粒刺穿能力和耐热性，因而能进一步改善电化学装置的安全性能。
在一些实施方式中，耐热层包含粘结剂。粘结剂可以将耐热颗粒粘结在基膜上，并且使耐热层与基膜之间获得较高的剥离强度。作为用于耐热层的粘结剂的示例，可包括聚丙烯酸酯、聚丁二烯-苯乙烯共聚物、聚丙烯酸、聚丙烯氰-丙烯酸共聚物、聚四氟乙烯、聚偏氟乙烯、聚甲基丙烯酸甲酯、聚偏氟乙烯-六氟丙烯共聚物中的一种或几种。
在一些实施方式中，耐热层的厚度≥0.1mm。可选地，耐热层的厚度为0.1mm～10mm，0.5mm～8mm，0.1mm～5mm，1mm～5mm，或1mm～3mm。耐热层的厚度满足上述条件，能有效地改善隔离膜的抵抗异物颗粒刺穿能力和耐热性。
在一些实施方式中，耐热层与基膜之间的剥离强度≥10N/m，可选地为10N/m～200N/m，15N/m～200N/m，15N/m～100N/m，20N/m～50N/m，20N/m～200N/m，30N/m～200N/m，或40N/m～200N/m。耐热层与基膜之间的剥离强度较高，则隔离膜的层间粘结性较好。因此，隔离膜的抵抗异物颗粒刺穿能力和耐热性能得到进一步改善。
在一些实施方式中，隔离膜满足：MD方向的热收缩率(l M0-l M)/l M0×100％≤30％，可选地，(l M0-l M)/l M0×100％≤20％，≤15％，≤12％，≤10％，≤5％，≤3％，或≤2.5％。l M表示隔离膜的MD方向长度l M0为100mm且TD方向长度l T0为100mm的试样于130℃保持1h后的以mm计的MD方向长度。
在一些实施方式中，隔离膜满足：TD方向的热收缩率(l T0-l T)/l T0×100％≤30％，可选地，(l T0-l T)/l T0×100％≤20％，≤15％，≤12％，≤10％，≤5％，≤3％，或≤2.5％。l T表示所述隔离膜的MD方向长度l M0为100mm且TD方向长度l T0为100mm的试样于130℃保持1h后的以mm计的TD方向长度。
可以将隔离膜裁成MD方向长度l M0为100mm且TD方向长度l T0为100mm的试样，试样的MD方向与隔离膜的MD方向平行，试样的TD方向与隔离膜的TD方向平行；将试样放入130℃烘箱中加热1h；测试试样在加热后的MD方向长度l M或TD方向长度l T，并计算MD或TD方向的热收缩率。测试可参考国标GB/T 36363-2018。
隔离膜在受热条件的收缩率较小，因而耐热性较高，有助于进一步改善电化学装置的安全性能。
在一些实施方式中，隔离膜被横截面积为0.5mm 2的针刺穿，并在150℃下保持10min后，针孔的扩孔率≤8％，可选地为≤7％，≤6％，≤5％，≤4.5％，≤4％，≤3％，或≤2.5％。所述扩孔率为(S 1-S 0)/S 0×100％，S 0表示针孔的初始面积，S 1表示在150℃下保持10min后的针孔面积。针的横截面积例如为圆形。S 0和S 1分别可采用本领域已知的仪器和方法测试。例如显微镜。作为示例，可使用昆山高品精密仪器有限公司的GP-300C-13.3寸显示-0.5x物镜，通过仪器放大，用系统自带的面积标注模块标识孔面积。隔离膜被针刺穿后，在受热条件下的针孔扩孔率较小，则其耐热性较高，特别是较小的破裂面积能降低电化学装置发生热失控的风险。
聚乙烯类聚合物的结晶度为本领域公知的含义，可采用本领域已知的仪器和方法测试。示例性测试方法如下：采用差示扫描量热法(DSC)测试聚乙烯类聚合物的熔融焓，然后除以100％结晶度的聚乙烯类聚合物的熔融焓，得到结晶度。测试可使用差示扫描量热仪DSC(例如德国耐驰NETZSCH的DSC214)进行。测试可参考标准GB/T 19466.3-2004。
聚乙烯类聚合物的重均分子量为本领域公知的含义，可采用本领域已知的仪器和方法测试。例如高温凝胶色谱法。测试可采用凝胶渗透色谱(GPC)仪进行，例如Polymer Char GPC-IR高温凝胶色谱仪。测试可参考国际标准ISO 16014-1-2019。
基膜、隔离膜和耐热层的厚度均为本领域公知的含义，可采用本领域已知的仪器和方法测试。隔离膜厚度的示例性测试方法如下：取长500mm×宽100mm的样品；在样品上均匀取5个点(例如沿样品的长度方向每隔100mm取一个点)，采用万分测厚仪测试该5个不同位置的隔离膜厚度，取平均值作为隔离膜的厚度。样品的长度方向与隔离膜的TD方向平行。可参照上述方法测试基膜的厚度。若隔离膜的单面设有耐热层，将隔离膜的厚度减去基膜的厚度，即为耐热层的厚度。若隔离膜的相对两面分设有待测耐热层和该待测耐热层的相对侧的耐热层，将隔离膜的厚度减去基膜与相对侧耐热层的厚度之和，即为该待测耐热层的厚度。
基膜的孔隙率均为本领域公知的含义，可采用本领域已知的仪器和方法测试。示例性测试方法如下：取5片100mm×100mm的基膜样品，分别测试重量并取平均值作为基膜重量M(mg)，利用计算公式X＝[1-M/(T×S×ρ)]×100％计算基膜的孔隙率X，其中，T为基膜的厚度，S为基膜的面积、ρ为基膜配料中聚合物的密度。
耐热层与基膜之间的剥离强度为本领域公知的含义，可采用本领域已知的仪器和方法测试。示例性测试方法如下：将绿胶与隔离膜的耐热层的表面粘接；然后裁成15mm的宽度w；将耐热层和基膜以50mm/min进行180°的剥离；根据拉力和位移的数据图，读取最大拉力x(N)，根据F’＝x/w计算得到耐热层与基膜之间的剥离强度F’(N/m)。拉 伸设备可采用高铁检测仪器公司的拉力机，例如AI-3000-S型。
图1示出作为一个示例的隔离膜。隔离膜包括基膜10和层合设置于基膜10任一表面的耐热层20。如图1-图3所示，基膜10为微孔性多孔薄膜。耐热层20为包含耐热颗粒的微孔性多孔膜层。图1的隔离膜仅是示例性的。例如在其他示例中，隔离膜可包括基膜10和层合设置于基膜10厚度方向相对的两个表面上的耐热层20。
本申请还提供一种隔离膜的制备方法。根据该制备方法能制备得到本申请所述的隔离膜。制备方法包括步骤(a)～(f)。
(a)提供包含聚合物和成孔剂的熔融态基膜配料。
(b)将基膜配料挤出并冷却形成片材。
(c)对片材进行MD方向拉伸。
(d)对片材进行TD方向拉伸。
(e)去除片材中的成孔剂，形成多孔片材。
(f)将多孔片材进行热定型，得到基膜。
在一些实施方式中，步骤(a)所述聚合物可选自如本文所描述的那些，例如选自聚乙烯类聚合物。成孔剂可采用本领域已知的用于聚合物薄膜形成多孔结构的物质，例如石蜡油。在一些实施例中，聚合物和成孔剂的重量比可选为20:80～60:40，进一步可选地为35:75～50:50，或30:70～40:60。作为示例，可将包含聚合物与石蜡油进行混炼，形成熔融态基膜配料。混炼的温度可以为180℃～250℃，可选地为190℃～245℃。由此，聚合物和成孔剂能实现充分、均匀地混合。混炼可以在本领域已知的装置进行，例如挤出机，进一步例如双螺杆挤出机。
在一些实施方式中，步骤(b)可将熔融态基膜配料经成型模具挤出，呈片状流延至冷却辊上，从而冷却形成片材。冷却的温度可选为15℃～30℃，进一步可选地为15℃～25℃，或20℃～25℃。由于冷却的温度较低，聚合物能快速发生冷却，由此可以降低基膜的结晶度，从而提高延伸率。
作为示例，熔融态基膜配料经过挤出机的齿轮泵与过滤器后，通过双流道交叉模头均匀挤出。挤出后的基膜配料垂直流延至流延机组的冷却辊上，经冷却形成片材。冷却辊可采用纯水冷冻的冷却方式来达到所需的冷却温度。
步骤(c)所述MD方向拉伸可采用本领域已知的方法和装置进行。例如纵拉机。在一些实施方式中，MD方向拉伸的拉伸倍率为3～6倍，可选地为3～5倍，3～4.5倍，3.5～4.5倍，3～4倍，或4～5倍。MD方向的拉伸倍率在适当范围内，能在保证基膜的强度的同时，降低基膜在MD方向的取向度，提高基膜延伸率。步骤(c)所述MD方向拉伸可在90℃～120℃温度条件下进行。
在一些实施方式中，经MD方向拉伸后的片材厚度可以为0.3mm±0.1mm。这样可以获得较小厚度的基膜。
步骤(d)所述TD方向拉伸可采用本领域已知的方法和装置进行。例如横拉机。作为示例，使片材进入第一横拉机(TDO1)中进行TD方向拉伸。第一横拉机可包含预热、拉伸、定型三个区域。步骤(d)所述TD方向拉伸的温度可设定在90℃～120℃。
在一些实施方式中，步骤(d)所述TD方向拉伸的拉伸倍率为3～6倍，可选地为3～5倍，3～4.5倍，3.5～4.5倍，3.5～5倍，或4～5倍等。
在一些实施方式中，本申请的制备方法先实施步骤(c)的MD方向拉伸，再实施步骤(d)的TD方向拉伸。这样能更好地改善基膜的强度和延伸率。
步骤(e)可采用本领域已知的方式去除片材中的成孔剂，以形成多孔片材。例如采用萃取剂萃取去除成孔剂。萃取剂的示例包括二氯甲烷。萃取可以在本领域已知的装置中进行。作为具体的示例，可以将片材牵引至具有内循环萃取装置的萃取工段，采用内循环萃取形式，薄膜在萃取剂中反向冲洗，利用萃取剂将片材中的成孔剂去除完全。经萃取处理的片材进行干燥，得到多孔片材。干燥可以在本领域已知的装置中进行，例如干燥炉。
在一些实施方式中，步骤(e)可以在步骤(c)和步骤(d)之后进行。这样能更好地改善基膜的强度和延伸率。
在一些实施方式中，热定型步骤(f)可包括在130℃以上的温度下对多孔片材进行热定型。可选地，热定型温度为130℃～150℃，还可选为134℃～145℃。基膜经TD方向拉伸后的TD方向取向度增大。热定型温度在适当范围内，可以适当减小基膜在TD方向的取向度，从而增加基膜的延伸率。
步骤(f)可采用本领域已知的方法和装置对多孔片材进行热定型。例如横拉机。作为示例，可将多孔片材牵引至第二横拉机(TDO2)中进行热定型。第二横拉机可包含预热、拉伸、定型三个区域。在热定型过程中，可对片材进行TD方向拉伸以确保其张紧。可选地，TD方向拉伸倍率为1～1.2，或1.05～1.15。
经热定型处理后所得基膜可进行收卷后备用。该基膜可作为隔离膜使用。在一些实施方式中，还可以对基膜进行后处理后用作隔离膜。例如，在基膜上形成隔热层。这样可以得到抗异物颗粒刺穿性能更好的耐热隔离膜。在这些实施方式中，隔离膜的制备方法还可包括步骤(g)，在基膜的至少一个表面形成耐热层。作为示例，可以在基膜自身厚度方向上的任意一个表面或两个表面形成耐热层。
步骤(g)中，耐热层可以由包含耐热颗粒的浆料涂覆在基膜的至少一个表面，并经干燥形成。耐热颗粒可选自如本文所描述的那些。浆料的溶剂可采用水性溶剂(如去离子水等)和有机溶剂(如N-甲基吡咯烷酮NMP、二甲基乙酰胺DMAC、丙酮等)中的一种或几种。浆料中还可以含有粘结剂。粘结剂可选自如本文所描述的那些。浆料的涂覆方式可以是凹版涂覆(如微凹版涂布)、浸涂、刮涂、线棒涂覆、喷涂、静电纺丝中的任一种或几种方式。
本申请还提供一种电化学装置。电化学装置包括本申请任意一种或几种隔离膜。因此，电化学装置可以具有较高的安全性能。
本申请的电化学装置可以是本领域技术人员能够想到的采用隔离膜的任意可发生电化学反应的装置。例如，电化学装置可以是一次电池、二次电池、燃料电池、太阳能电池或电容等。特别地，本申请的电化学装置是二次电池。二次电池的示例包括但不限于锂离子二次电池、钠离子二次电池、钾离子二次电池、镁离子二次电池等。
二次电池
二次电池包括正极极片、负极极片、隔离膜和电解质。在二次电池充放电过程中，活性离子在正极极片和负极极片之间往返嵌入和脱出。电解质在正极极片和负极极片之间起到传导离子的作用。隔离膜设置在正极极片和负极极片之间起到隔离的作用。
[正极极片]
正极极片包括正极集流体以及设置于正极集流体上的正极膜层。作为示例，正极集流体具有在自身厚度方向相对的两个表面，正极膜层层合于正极集流体相对的两个表面的其中任意一者或两者上。
正极膜层通常包含正极活性材料以及可选的粘结剂和可选的导电剂。通常是将正极活性材料以及可选的导电剂和可选的粘结剂等分散于溶剂中并搅拌均匀形成正极浆料，并经干燥、冷压形成正极膜层。溶剂可以是N-甲基吡咯烷酮(NMP)。
正极活性材料可选自本领域已知的能用于二次电池正极的活性材料。作为示例，正极活性材料可包括锂过渡金属氧化物和聚阴离子型正极材料中的一种或几种。锂过渡金属氧化物的示例可包括锂钴氧化物(如LiCoO 2)、锂镍氧化物(如LiNiO 2)、层状锂锰氧化物(如LiMnO 2)、锂镍钴锰氧化物(如LiNi aCo bMn 1-a-bO 2)、锂镍钴铝氧化物(如LiNi aCo bAl 1-a-bO 2)、锂镍钴氧化物(如LiNi yCo 1-yO 2)、层状锂钴锰氧化物(如LiCo yMn 1-yO 2)、锂钴铝氧化物(如LiCo yAl 1-yO 2)、锂钴硼氧化物(如LiCo yB 1-yO 2)、锂钴镁氧化物(如LiCo yMg 1-yO 2)、锂钴钛氧化物(如LiCo yTi 1-yO 2)、锂钴钼氧化物(如LiCo yMo 1-yO 2)、锂钴锡氧化物(如LiCo ySn 1-yO 2)、锂钴钙氧化物(如LiCo yCa 1- yO 2)、锂钴铜氧化物(如LiCo yCu 1-yO 2)、锂钴钒氧化物(如LiCo yV 1-yO 2)、锂钴锆氧化物(如LiCo yZr 1-yO 2)、锂钴硅氧化物(如LiCo ySi 1-yO 2)、锂钴钨氧化物(如LiCo yW 1- yO 2)、锂钴钇氧化物(如LiCo yY 1-yO 2)、锂钴镧氧化物(如LiCo yLa 1-yO 2)、层状锂镍锰氧化物(如LiNi yMn 1-yO 2)、尖晶石锂锰氧化物(如LiMn 2O 4)、尖晶石锂镍锰氧化物(如LiNi 0.5Mn 1.5O 4)以及上述物质的改性材料中的一种或几种。聚阴离子型正极材料的示例可包括选自磷酸铁锂(如LiFePO 4)、磷酸锰锂(如LiMnPO 4)、磷酸钴锂(如LiCoPO 4)、磷酸镍锂(如LiNiPO 4)、磷酸锰铁锂(如LiFe yMn 1-yPO 4)以及上述物质的改性材料中的一种或几种。前述改性材料可以是包覆改性和/或掺杂改性。在出现时，a表示0＜a＜1，b表示0＜b＜1。在出现时，y独立地表示0＜y＜1。
粘结剂能将正极活性材料及可选的导电剂稳定地粘结于正极集流体上。在一些实施例中，正极膜层的粘结剂可选自聚偏氟乙烯(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、以及上述物质的改性聚合物中的一种或几种。
导电剂能改善正极膜层的电子传导性能。在一些实施例中，正极膜层的导电剂可选自超导碳、炭黑(如Super P、乙炔黑、科琴黑)、碳点、碳纳米管、石墨烯及碳纳米纤维中一种或几种。
正极集流体可采用具有良好导电性及机械强度的材质，起导电和集流的作用。作为示例，正极集流体可采用铝箔、镍箔或者二者复合形成的金属箔。
[负极极片]
在一些实施方式中，负极极片中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。作为示例，负极集流体具有在自身厚度方向相对的两个表面，负极膜层层合于负极集流体相对的两个表面的其中任意一者或两者上。
负极膜层通常包含负极活性材料以及可选地粘结剂、可选地导电剂和其它可选助剂。通常是将负极活性材料以及可选地导电剂、可选地粘结剂、可选助剂等分散于溶剂中并搅拌均匀形成负极浆料，并经干燥、冷压形成负极膜层。溶剂可以是N-甲基吡咯烷酮(NMP)或去离子水。
负极活性材料可选自本领域已知的能用于二次电池负极的活性材料。在一些实施例中，负极活性材料可选自石墨类碳材料(例如人造石墨、天然石墨)、非石墨类碳材料(例如硬碳等)、金属锂、锂合金(例如Li-Mg合金、Li-Cu-Sn合金等)、单质硅、硅基合金(例如Mg-Si合金等)、硅基氧化物(例如SiO等)、单质锡、锡基合金(例如Sn-Sb合金等)、锡基氧化物(例如SnO、SnO 2等)、其他金属氧化物(例如Li zFe 2O 3、Li zWO 2、PbO、PbO 2、Pb 2O 3、Pb 3O 4、Sb 2O 3、Sb 2O 4、Sb 2O 5、GeO、GeO 2、Bi 2O 3、Bi 2O 4、Bi 2O 5等)、导电聚合物(例如聚乙炔、聚苯胺、聚噻吩等)中的一种或几种。在出现时，0＜z＜1。可选地，负极活性材料包括人造石墨和天然石墨中的一种或几种。
导电剂能改善负极膜层的电子传导性能。在一些实施例中，负极膜层的导电剂可选自超导碳、炭黑(例如Super P、乙炔黑、科琴黑等)、碳点、碳纳米管、石墨烯及碳纳米纤维中一种或几种。
粘结剂能将负极活性材料以及可选的导电剂稳定地粘结于负极集流体上。在一些实施例中，负极膜层的粘结剂可选自丁苯橡胶(SBR)、水性丙烯酸树脂、聚乙烯醇(PVA)、海藻酸钠(SA)及羧甲基壳聚糖(CMCS)中的一种或几种。
在一些实施例中，其它可选助剂例如是增稠剂(例如羧甲基纤维素钠CMC-Na)、PTC热敏电阻材料等。
负极集流体可采用具有良好导电性及机械强度的材质，起导电和集流的作用。在一些实施例中，负极集流体可以采用铜箔、镍箔、不锈钢片、钛箔、以及它们中的两者以上复合形成的金属箔。
在一些实施方式中，负极极片可采用锂基金属片。
[隔离膜]
隔离膜可选自本申请任意一种或几种隔离膜。在一些实施方式中，电化学装置中可选择本申请所述隔离膜和本领域已知的其他隔离膜进行组合使用。电化学装置包括本申请的隔离膜，因而能具有相同或类似的有益效果。
[电解质]
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，电解质可选自固态电解质(例如无机固态电解质、聚合物固态电解质、有机-无机复合固态电解质)、或液态电解质(即电解液)。在一些实施方式中，电解质选自电解液。电解液包括电解质盐和溶剂。
电解质盐在溶剂中能解离成阴离子和阳离子。阳离子可包括锂离子、钠离子、钾离子、镁离子中的一种或几种。阴离子可包括PF 6 ﹣、BF 4 ﹣、Cl ﹣、Br ﹣、I ﹣、ClO 4 ﹣、AsF 6 ﹣、双氟磺酰亚胺阴离子N(SO 2F) 2 ﹣、双三氟甲磺酰亚胺阴离子N(CF 3SO 2) 2 ﹣、醋酸根阴离子CH 3CO 2 ﹣、三氟甲磺酸CF 3SO 3 ﹣、二氟草酸硼酸阴离子(结构式A1)、二草酸硼酸阴离子(结构式A2)、二氟磷酸离子PO 2F 2 ﹣、二氟二草酸磷酸阴离子(结构式A3)、四氟草酸磷酸阴离子(结构式A4)中的一种或几种。
Figure PCTCN2021109904-appb-000003
在一些实施例中，电解质盐可选自六氟磷酸锂(LiPF 6)、四氟硼酸锂(LiBF 4)、高氯酸锂(LiClO 4)、六氟砷酸锂(LiAsF 6)、双氟磺酰亚胺锂(LiFSI)、双三氟甲磺酰亚胺锂(LiTFSI)、三氟甲磺酸锂(LiTFS)、二氟草酸硼酸锂(LiDFOB)、二草酸硼酸锂(LiBOB)、二氟磷酸锂(LiPO 2F 2)、二氟二草酸磷酸锂(LiDFOP)及四氟草酸磷酸锂(LiTFOP)中的一种或几种。
溶剂可采用有机溶剂。在一些实施例中，溶剂可选自碳酸亚乙酯(EC)、碳酸亚丙酯(PC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)、碳酸二甲酯(DMC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸亚丁酯(BC)、氟代碳酸亚乙酯(FEC)、甲酸甲酯(MF)、乙酸甲酯(MA)、乙酸乙酯(EA)、乙酸丙酯(PA)、丙酸甲酯(MP)、丙酸乙酯(EP)、丙酸丙酯(PP)、丁酸甲酯(MB)、丁酸乙酯(EB)、1,4-丁内酯(GBL)、环丁砜(SF)、二甲砜(MSM)、甲乙砜(EMS)、二乙砜(ESE)、二甲基亚砜(DMSO)、乙腈、四氢呋喃(THF)、N-甲基吡咯烷酮(NMP)中的一种或几种。
在一些实施例中，电解液中还可选地包括添加剂。例如添加剂可以包括负极成膜添加剂，也可以包括正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温性能的添加剂、改善电池低温性能的添加剂等。
正极极片、负极极片和隔离膜可经叠片工艺或卷绕工艺制成电极组件，使隔离膜处于正极极片与负极极片之间起到隔离的作用；将电极组件置于外包装中，注入电解液并封口，即可得到二次电池。电极组件中的隔离膜至少包括一种或几种如本申请所述的隔离膜。
二次电池的外包装用于封装电极组件和电解质。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，如可包括聚丙烯(PP)、聚对苯二甲酸丁二醇酯(PBT)、聚丁二酸丁二醇酯(PBS)等中的一种或几种。
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。如图4是作为一个示例的方形结构的二次电池5。
在一些实施例中，参照图5，外包装可包括壳体51和盖板53。壳体51可包括底板和连接于底板的侧板，底板和侧板围合成容纳腔。壳体51具有与容纳腔连通的开口，盖板53能够盖设于开口，以封闭容纳腔。电极组件52封装于容纳腔。电解液浸润于电极组件52中。二次电池5所含电极组件52的数量可以为一个或几个，可根据需求来调节。
本申请还提供一种电化学设备。电化学设备包括本申请任意一种或几种电化学装置。因此电化学设备也具有与电化学装置相同或类似的有益效果，如较高的安全性能。
在一些实施例中，电化学设备可包括多个电化学装置。电化学设备所含电化学装置的具体数量可以根据电化学设备的应用和容量来调节。并且根据不同的应用需求，多个电化学装置之间可以串联连接、并联连接或串并联混合连接。
在一些实施例中，电化学设备可以是电池组。电池组的示例包括电池模块、电池包等。电池模块可由多个二次电池组装而成。电池模块所含二次电池的具体数量可以根据电池模块的应用和容量来调节。电池包可由多个二次电池或多个电池模块组装而成。电池包所含二次电池或电池模块的数量可以根据电池包的应用和容量进行调节。
图6是作为一个示例的电池模块4。参照图6，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，以容纳多个二次电池5。
图7和图8是作为一个示例的电池包1。参照图7和图8，在电池包1中可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。
本申请还提供一种用电装置，所述用电装置包括本申请所述的电化学装置或电化学设备中的至少一种。所述电化学装置或电化学设备可以用作所述用电装置的电源，也可以作为所述用电装置的能量存储单元。在一些实施例中，用电装置可包括本申请所述的二次电池、电池模块、或电池包中的至少一种。可以根据所述用电装置的实际使用需求来选择。所述用电装置可包括移动设备(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。
图9是作为一个示例的用电装置。该装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。该用电装置可采用电池包或电池模块作为电源。
作为另一个示例的用电装置可以是手机、平板电脑、笔记本电脑等。该用电装置可采用二次电池作为电源。
实施例
下述实施例更具体地描述了本申请公开的内容，这些实施例仅仅用于阐述性说 明，因为在本申请公开内容的范围内进行各种修改和变化对本领域技术人员来说是明显的。除非另有声明，以下实施例中所报道的所有份、百分比、和比值都是基于重量计，而且实施例中使用的所有试剂都可商购获得或是按照常规方法进行合成获得，并且可直接使用而无需进一步处理，以及实施例中使用的仪器均可商购获得。
实施例1
隔离膜的制备
基膜的制备：将重均分子量为200万且结晶度为53％的PE(即第一聚乙烯)、重均分子量为60万且结晶度为50％的PE(即第二聚乙烯)与石蜡油按重量比2:1:7混合，挤出，经T型口模高温挤出片状薄膜，流延至20℃的冷却辊冷却；经MD方向拉伸，再经TD方向拉伸；萃取除去石蜡油；然后热定型，分切即制成基膜。MD方向的拉伸倍率为4，拉伸温度为114℃；MD方向拉伸后的片材厚度为0.3mm；TD方向的拉伸倍率为4.4，拉伸温度为116℃；热定型的温度为135℃。
所得基膜的MD方向拉伸断裂时的力值F M为17.79N，MD方向拉伸断裂时的拉伸位移ΔL M为98mm，MD方向的单位厚度拉伸能量C M为2.49J/10μm；MD方向延伸率δ M为245％。所得基膜的TD方向拉伸断裂时的力值F T为16.13N，TD方向拉伸断裂时的拉伸位移ΔL T为78mm，TD方向的单位厚度拉伸能量C T为1.8J/10μm；TD方向延伸率δ T为195％。基膜的孔隙率为30％。基膜的厚度d为7μm。
耐热层的制备：将97重量份的氧化铝颗粒与3重量份的聚丙烯酸酯粘结剂加入去离子水中，混合均匀制成浆料；然后采用微凹版涂布方式，将浆料均匀涂布到基膜的自身厚度方向的任意一个表面；经烘箱干燥后，得到耐热层。耐热层的厚度为3μm。
正极极片的制备
将94重量份正极活性材料锂钴氧化物(也称钴酸锂)、3重量份导电碳、3重量份粘结剂PVDF加入溶剂NMP中，搅拌混合均匀后，涂覆于Al箔表面，经烘干、冷压、分条，得到正极极片。
负极极片的制备
将97.5重量份负极活性材料人造石墨、1.5重量份粘结剂SBR，1重量份增稠剂CMC-Na加入去离子水，搅拌混合均匀后，涂覆于Cu箔表面，经烘干、冷压、分条，得到负极极片。
电解液的制备
将11.9重量份的六氟磷酸锂加入到88.1重量份的PC、EC和DEC(质量比为1:1:1)的溶液中，均匀搅拌充分溶解后，得到电解液。
锂离子二次电池的制备
将上述正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正、负极极片之间起到隔离作用，并卷绕得到裸电芯。将裸电芯置于外包装中，注入电解液并封装、化成后，制成锂离子二次电池。
实施例2～6及对比例1～2：制备方法与实施例1类似，不同的是，调整隔离膜的制备步骤中的相关参数，详见表1。表1中，重量比是第一聚乙烯的重量:第二聚乙烯的重量:成孔剂石蜡油的重量。
实施例7～28：制备方法与实施例3类似，不同的是，调整隔离膜的耐热层制备步骤中的相关参数，详见表4。
对比例3～7：制备方法与对比例1类似，不同的是，调整隔离膜的耐热层制备步骤中的相关参数，详见表4。
测试部分
(1)二次电池自放电测试
取1000个上述制备的二次电池，在常温(25℃)下以0.5C倍率恒流充电至4.4V，然后恒压充电至0.05C；再以0.5C恒流放电至3.9V；常温静置48h后测试二次电池的开路电压V 1；然后继续常温静置48h后，测试电芯的开路电压V 2；自放电计算公式为：K＝(V 1-V 2)/48。K＞0.08的二次电池记为自放电不合格品。自放电不合格比例通过自放电不合格品数量与总样品数量的比值来计算。二次电池自放电不合格比例越低，则表明隔离膜的抵抗异物颗粒刺穿能力性能较高。
(2)二次电池针刺测试
取10个上述制备的二次电池，在室温下，以1A电流恒流充电至企业技术条件中规定的充电终止电压(本实施例测试中是4.4V)时转恒压充电，至充电电流降至0.05A时停止充电，充电后搁置1h。用直径5mm的耐高温钢针，以25±5mm/s的速度，从垂直于蓄电池极板的方向贯穿，贯穿位置宜靠近所刺面的几何中心，钢针停留在二次电池中，观察1h。不爆炸，不起火视为合格。合格率通过合格品数量与总样品数量的比值来计算。
表1：隔离膜制备参数
Figure PCTCN2021109904-appb-000004
表2：隔离膜测试结果
Figure PCTCN2021109904-appb-000005
由表2的结果可知，本申请实施例的隔离膜中，由于基膜具有较高的MD方向单位厚度拉伸能量和TD方向单位厚度拉伸能量，且基膜在MD方向和TD方向的延伸率较高，因而隔离膜在高温下的收缩率和扩孔率均较低，从而能起到良好的隔离正、负极的作用，提升电池安全性能。
对比例1和对比例2的隔离膜由于MD方向单位厚度拉伸能量和TD方向单位厚度拉伸能量较低，且基膜在MD方向和TD方向的延伸率较小，导致隔离膜在高温下的收缩率和扩孔率均较大，不利于电池的安全性能。
表3：二次电池测试结果
序号 自放电坏品比例 针刺测试合格率
实施例1 4.2％ 100％
实施例2 1.1％ 100％
实施例3 1.2％ 100％
实施例4 1.0％ 100％
实施例5 1.0％ 100％
实施例6 1.4％ 100％
对比例1 2.0％ 40％
对比例2 1.9％ 50％
由表3的结果可知，本申请实施例的隔离膜中，由于基膜具有较高的MD方向单位厚度拉伸能量和TD方向单位厚度拉伸能量，且基膜在MD方向和TD方向的延伸率较高，由此隔离膜能有效抑制颗粒物的刺穿，特别是在针刺等极端情况下，隔离膜的破损面积较小，因而降低了电池发生热失控的风险。因此，采用本申请隔离膜的二次电池能同时兼顾较低的自放电坏品比例和较高的针刺测试合格率，从而获得较高的安全性能。
对比例1和对比例2的隔离膜由于MD方向单位厚度拉伸能量和TD方向单位厚度拉伸能量较低，且基膜在MD方向和TD方向的延伸率较小，采用其的电池的安全性能较差。
表4：隔离膜制备参数
Figure PCTCN2021109904-appb-000006
表4中耐热层的厚度指的是单侧耐热层的厚度。对于双面涂布耐热层的隔离膜，每侧表面上的耐热层的厚度相等。
表5：隔离膜及二次电池测试结果
Figure PCTCN2021109904-appb-000007
由表5的结果可知，对耐热层进行优化设计，能进一步提升隔离膜的性能，从而改善电池安全性能。
特别地，由实施例3、7-10的比较可知，耐热层选择适当的耐热颗粒，有助于使隔离膜具有较低的热收缩率和针孔扩孔率，尤其是使电池获得较低的自放电概率和较高 的针刺安全性能。
由实施例3、11-16的比较，以及实施例17-23的比较可知，耐热层的厚度在适当范围内，可以在确保隔离膜具有较小厚度的前提下，进一步降低隔离膜的热收缩率和针孔扩孔率，并且进一步降低电池的自放电概率和提高针刺安全性能。
由实施例3、24-28，以及对比例1、3-6的比较可知，耐热层具有适当的耐热颗粒占比，有助于进一步降低隔离膜的热收缩率和针孔扩孔率，以及进一步降低电池的自放电概率和提高针刺安全性能。而满足基膜的MD方向单位厚度拉伸能量和TD方向单位厚度拉伸能量以及MD方向和TD方向的延伸率均在适当范围内的隔离膜的性能更好，采用其的二次电池的安全性能更高。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到各种等效的修改或替换，这些修改或替换都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以权利要求的保护范围为准。

Claims (21)

  1. 一种隔离膜，包括基膜，
    所述基膜在纵向MD方向和横向TD方向的单位厚度拉伸能量均≥1.8J/10μm，且所述基膜在MD方向和TD方向的延伸率均≥150％；
    其中，所述单位厚度拉伸能量为
    Figure PCTCN2021109904-appb-100001
    F表示所述基膜的标距长度为40mm且宽度为15mm的试样以50mm/min的恒速拉伸至断裂时的以N计的力值，ΔL表示所述拉伸断裂时的以m计的拉伸位移，d表示所述试样的以μm计的初始厚度；
    所述基膜的厚度为2μm～40μm。
  2. 根据权利要求1所述的隔离膜，其中，所述基膜在MD方向的单位厚度拉伸能量为1.8J/10μm～50J/10μm，可选地为2.4J/10μm～50J/10μm，进一步可选地为2.7J/10μm～30J/10μm；和/或，
    所述基膜在TD方向的单位厚度拉伸能量为1.8J/10μm～50J/10μm，可选地为2J/10μm～50J/10μm，进一步可选地为2.5J/10μm～30J/10μm。
  3. 根据权利要求1或2所述的隔离膜，其中，所述基膜在MD方向的延伸率为150％～4000％，可选地为180％～4000％，进一步可选地为200％～2000％；和/或，
    所述基膜在TD方向的延伸率为150％～4000％，可选地为180％～4000％，进一步可选地为200％～2000％。
  4. 根据权利要求1-3任一项所述的隔离膜，其中，所述基膜为聚合物基膜，基于所述基膜的配料中聚合物的总质量，所述基膜中聚乙烯类聚合物的质量占比为50％以上，可选地为80％以上，进一步可选地为100％；
    其中，所述聚乙烯类聚合物包括聚乙烯、乙烯与α-烯烃的共聚物中的一种或几种，可选地，所述α-烯烃选自丙烯、1-丁烯、1-辛烯中的一种或几种。
  5. 根据权利要求4所述的隔离膜，其中，所述基膜包含两种以上的聚乙烯类聚合物，其中满足：1＜M1/M2≤50，可选地，2≤M1/M2≤30，进一步可选地，3≤M1/M2≤10，M1表示所述基膜的配料中具有最大重均分子量的聚乙烯类聚合物的重均分子量，M2表示所述基膜的配料中具有最小重均分子量的聚乙烯类聚合物的重均分子量。
  6. 根据权利要求5所述的隔离膜，其中，M1为110万～500万，可选地为150万～300万；和/或，M2为10万～100万，可选地为30万～100万。
  7. 根据权利要求4-6任一项所述的隔离膜，其中，基于所述基膜的配料中聚合物的总质量，所述基膜中所述具有最大重均分子量的聚乙烯类聚合物的质量占比为10％～100％，可选地为10％～90％，进一步可选地为30％～70％；和/或，
    基于所述基膜的配料中聚合物的总质量，所述基膜中所述具有最小重均分子量的聚乙烯类聚合物的质量占比为0～90％，可选地为10％～90％，进一步可选地为30％～70％。
  8. 根据权利要求4-7任一项所述的隔离膜，其中，所述聚乙烯类聚合物的结晶度≤65％，可选地为≤50％，进一步可选地为≤45％。
  9. 根据权利要求1-8任一项所述的隔离膜，其中，所述基膜的厚度为2μm～20μm，可选地为3μm～15μm，还可选地为3μm～10μm。
  10. 根据权利要求1-9任一项所述的隔离膜，其中，还包括耐热层，所述耐热层位于所述基膜的至少一个表面。
  11. 根据权利要求10所述的隔离膜，其中，所述耐热层包含耐热颗粒，所述耐热颗粒在所述耐热层中的质量占比≥40％，可选地为40％～99％，还可选地为80％～97％；
    可选地，所述耐热颗粒包括无机耐热颗粒、有机耐热颗粒中的一种或几种，其中，
    所述无机耐热颗粒可选地选自氧化铝、氧化硅、氧化钛、碳酸钙、氧化镁、氢氧化镁、勃姆石、钛酸钡、硫酸钡中的一种或几种；
    所述有机耐热颗粒可选地选自聚丙烯酸树脂、芳纶、聚苯硫醚、聚甲基丙烯酸甲酯、聚偏氟乙烯、聚四氟乙烯、聚偏氟乙烯-六氟丙烯共聚物中的一种或几种。
  12. 根据权利要求10-11任一项所述的隔离膜，其中，所述耐热层的厚度≥0.1mm，可选地为0.1mm～10mm，还可选地为1mm～3mm。
  13. 根据权利要求10-12任一项所述的隔离膜，其中，所述耐热层与所述基膜之间的剥离强度≥10N/m，可选地为15N/m～200N/m，进一步可选地为20N/m～200N/m。
  14. 根据权利要求1-13任一项所述的隔离膜，其中，所述隔离膜满足：
    (l M0-l M)/l M0×100％≤30％，可选地，(l M0-l M)/l M0×100％≤10％，进一步可选地，(l M0-l M)/l M0×100％≤5％，其中l M表示所述隔离膜的MD方向长度l M0为100mm且TD方向长度l T0为100mm的试样于130℃保持1h后的以mm计的MD方向长度；和/或，
    (l T0-l T)/l T0×100％≤30％，可选地，(l T0-l T)/l T0×100％≤10％，进一步可选地，(l T0-l T)/l T0×100％≤5％，其中l T表示所述隔离膜的MD方向长度l M0为100mm且TD方向长度l T0为100mm的试样于130℃保持1h后的以mm计的TD方向长度。
  15. 根据权利要求1-14任一项所述的隔离膜，其中，所述隔离膜被横截面积为0.5mm 2的针刺穿，并在150℃下保持10min后，针孔的扩孔率≤8％，可选地为≤5％，进一步可选地为≤4％，更进一步可选地为≤3％；
    其中，所述扩孔率为(S 1-S 0)/S 0×100％，S 0表示针孔的初始面积，S 1表示在150℃下保持10min后的针孔面积。
  16. 一种隔离膜的制备方法，包括：
    (a)提供包含聚合物和成孔剂的熔融态基膜配料；
    (b)将所述基膜配料挤出并冷却形成片材；
    (c)对所述片材进行MD方向拉伸；
    (d)对所述片材进行TD方向拉伸；
    (e)去除所述片材中的所述成孔剂，形成多孔片材；
    (f)将所述多孔片材进行热定型，得到基膜；
    其中，所述基膜用作隔离膜，或所述基膜进行后处理后用作隔离膜；
    所述基膜在纵向MD方向和横向TD方向的单位厚度拉伸能量均≥1.8J/10μm，且所述基膜在MD方向和TD方向的延伸率均≥150％；
    其中，所述单位厚度拉伸能量为
    Figure PCTCN2021109904-appb-100002
    F表示所述基膜的标距长度为40mm且宽度为15mm的试样以50mm/min的恒速拉伸至断裂时的以N计的力值，ΔL表示所述拉伸断裂时的以m计的拉伸位移，d表示所述试样的以μm计的初始厚度；
    所述基膜的厚度为2μm～40μm。
  17. 根据权利要求16所述的方法，其中，所述基膜进行后处理，包括：(g)在基膜的至少一个表面形成耐热层。
  18. 根据权利要求16或17所述的方法，其中，所述方法满足如下(1)-(4)中的一项或多项：
    (1)步骤(b)所述冷却的温度为15℃～30℃，可选地为20℃～25℃；
    (2)步骤(c)所述MD方向拉伸的拉伸倍率为3～6倍，可选地为3～5倍，还可选为3～4.5倍；
    (3)步骤(d)所述TD方向拉伸的拉伸倍率为3～6倍，可选地为3～5倍，还可选为3.5～5倍；
    (4)步骤(f)所述热定型包括在130℃以上的温度下对所述多孔片材进行热定型，可选地，所述温度为130℃～150℃，还可选为134℃～145℃。
  19. 一种电化学装置，包括根据权利要求1-15任一项所述的隔离膜或根据权利要求16-18任一项所述方法制备得到的隔离膜。
  20. 一种电化学设备，包括根据权利要求19所述的电化学装置。
  21. 一种用电装置，包括根据权利要求19所述的电化学装置或根据权利要求20所述的电化学设备中的至少一种。
PCT/CN2021/109904 2021-07-30 2021-07-30 隔离膜及其制备方法、电化学装置、电化学设备和用电装置 WO2023004820A1 (zh)

Priority Applications (3)

Application Number Priority Date Filing Date Title
PCT/CN2021/109904 WO2023004820A1 (zh) 2021-07-30 2021-07-30 隔离膜及其制备方法、电化学装置、电化学设备和用电装置
CN202180078478.4A CN116802225A (zh) 2021-07-30 2021-07-30 隔离膜及其制备方法、电化学装置、电化学设备和用电装置
EP21943333.1A EP4148890A1 (en) 2021-07-30 2021-07-30 Isolation film and preparation method therefor, electrochemical apparatus, electrochemical device, and electric apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2021/109904 WO2023004820A1 (zh) 2021-07-30 2021-07-30 隔离膜及其制备方法、电化学装置、电化学设备和用电装置

Publications (1)

Publication Number Publication Date
WO2023004820A1 true WO2023004820A1 (zh) 2023-02-02

Family

ID=85087380

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/109904 WO2023004820A1 (zh) 2021-07-30 2021-07-30 隔离膜及其制备方法、电化学装置、电化学设备和用电装置

Country Status (3)

Country Link
EP (1) EP4148890A1 (zh)
CN (1) CN116802225A (zh)
WO (1) WO2023004820A1 (zh)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102774009A (zh) * 2012-08-07 2012-11-14 重庆纽米新材料科技有限责任公司 聚烯烃微孔膜的制备方法
CN106575734A (zh) * 2014-06-20 2017-04-19 东丽电池隔膜株式会社 聚烯烃微多孔质膜、电池用隔膜以及电池
CN106661264A (zh) * 2014-08-12 2017-05-10 东丽电池隔膜株式会社 聚烯烃微多孔膜及其制造方法、非水电解液系二次电池用隔膜、以及非水电解液系二次电池
CN110114397A (zh) * 2017-03-08 2019-08-09 东丽株式会社 聚烯烃微多孔膜

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102774009A (zh) * 2012-08-07 2012-11-14 重庆纽米新材料科技有限责任公司 聚烯烃微孔膜的制备方法
CN106575734A (zh) * 2014-06-20 2017-04-19 东丽电池隔膜株式会社 聚烯烃微多孔质膜、电池用隔膜以及电池
CN106661264A (zh) * 2014-08-12 2017-05-10 东丽电池隔膜株式会社 聚烯烃微多孔膜及其制造方法、非水电解液系二次电池用隔膜、以及非水电解液系二次电池
CN110114397A (zh) * 2017-03-08 2019-08-09 东丽株式会社 聚烯烃微多孔膜

Also Published As

Publication number Publication date
EP4148890A1 (en) 2023-03-15
CN116802225A (zh) 2023-09-22

Similar Documents

Publication Publication Date Title
US9401505B2 (en) Separator including coating layer of inorganic and organic mixture, and battery including the same
US10096811B2 (en) Separator for a non-aqueous secondary battery and non-aqueous secondary battery
CN103891000B (zh) 非水系二次电池用隔膜及非水系二次电池
CN103890998B (zh) 非水系二次电池用隔膜及非水系二次电池
KR101079456B1 (ko) 세퍼레이터 및 비수 전해질 이차전지
US20110300430A1 (en) Separator for battery, and non-aqueous lithium battery
CN112889164B (zh) 锂金属电池及其制备方法、包含锂金属电池的装置和负极极片
US20180294455A1 (en) Porous film and electricity storage device
WO2022105614A1 (zh) 锂金属负极、其制备方法及其相关的锂金属电池和装置
CN103891001A (zh) 非水系二次电池用隔膜及非水系二次电池
WO2020238156A1 (zh) 正极集流体、正极极片、电化学装置及装置
US11923537B2 (en) Negative electrode plate, secondary battery, and apparatus contianing the secondary battery
JP6723052B2 (ja) 蓄電デバイス用セパレータ
CN103283076A (zh) 非水电解质及使用其的非水电解质二次电池
JP5500425B2 (ja) 非水系リチウム二次電池
JP7483911B2 (ja) セパレーター、二次電池及び電力消費装置
WO2023004820A1 (zh) 隔离膜及其制备方法、电化学装置、电化学设备和用电装置
JP6273731B2 (ja) リチウムイオン電池
JP5422373B2 (ja) 電池用セパレータおよび非水系リチウム二次電池
WO2024060176A1 (zh) 复合集流体及其制作方法、电极片、二次电池和用电装置
US11728100B2 (en) Polyolefin porous film, separator for energy storage device, and energy storage device
WO2023048190A1 (ja) 蓄電素子、蓄電素子の製造方法及び蓄電装置
WO2023236102A1 (zh) 二次电池及其制备方法、用电装置

Legal Events

Date Code Title Description
ENP Entry into the national phase

Ref document number: 2021943333

Country of ref document: EP

Effective date: 20221208

WWE Wipo information: entry into national phase

Ref document number: 202180078478.4

Country of ref document: CN

NENP Non-entry into the national phase

Ref country code: DE