WO2024192596A1 - 隔离膜、二次电池和用电装置 - Google Patents

隔离膜、二次电池和用电装置 Download PDF

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Publication number
WO2024192596A1
WO2024192596A1 PCT/CN2023/082339 CN2023082339W WO2024192596A1 WO 2024192596 A1 WO2024192596 A1 WO 2024192596A1 CN 2023082339 W CN2023082339 W CN 2023082339W WO 2024192596 A1 WO2024192596 A1 WO 2024192596A1
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WO
WIPO (PCT)
Prior art keywords
base film
film
isolation
optionally
isolation film
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/CN2023/082339
Other languages
English (en)
French (fr)
Inventor
王兆光
杨建瑞
孙成栋
黄思应
欧阳楚英
韩崇旺
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Contemporary Amperex Technology Co Ltd
Original Assignee
Contemporary Amperex Technology Co Ltd
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 Contemporary Amperex Technology Co Ltd filed Critical Contemporary Amperex Technology Co Ltd
Priority to KR1020257014382A priority Critical patent/KR20250073484A/ko
Priority to PCT/CN2023/082339 priority patent/WO2024192596A1/zh
Priority to CN202380045996.5A priority patent/CN119487689A/zh
Priority to JP2025525781A priority patent/JP2025536601A/ja
Priority to EP23927915.1A priority patent/EP4621972A4/en
Publication of WO2024192596A1 publication Critical patent/WO2024192596A1/zh
Priority to US19/260,486 priority patent/US20250337122A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/494—Tensile strength
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/426—Fluorocarbon polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/44—Fibrous material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—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
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application belongs to the technical field of secondary batteries, and specifically relates to an isolation membrane, a secondary battery and an electrical device.
  • Secondary batteries are widely used in various consumer electronic products and electric vehicles due to their outstanding features of light weight, no pollution and no memory effect. With the continuous development of the new energy industry, users have put forward higher requirements for the reliability of secondary batteries.
  • the present application provides a separator, a secondary battery and an electrical device, aiming to improve the reliability of the secondary battery.
  • the first aspect of the present application provides an isolation film, which includes: a first base film and a second base film, the melting point of the second base film is lower than the melting point of the first base film; the puncture strength of the second base film is 220gf-460gf, and the puncture strength of the isolation film is 330gf-620gf.
  • the present application includes at least the following beneficial effects: the isolation membrane provided by the present application, by setting the melting point of the second base membrane to be lower than the melting point of the first base membrane, and the puncture strength of the second base membrane and the puncture strength of the isolation membrane are selected within the above-mentioned range, so that the isolation membrane has different degrees of puncture resistance, that is, the puncture resistance of one side is different from that of the other side.
  • the isolation membrane has different degrees of puncture resistance, that is, the puncture resistance of one side is different from that of the other side.
  • the ratio of the puncture strength of the first base film to the puncture strength of the second base film is 0.2-0.95, and can be 0.3-0.75.
  • the separator has good puncture resistance and can balance other properties, thereby further improving the reliability of the secondary battery.
  • the puncture strength of the first base film is 100gf-220gf; the puncture strength of the second base film is 260gf-400gf.
  • the separator has good puncture resistance, which can further improve the reliability of the secondary battery.
  • the isolation film satisfies at least one of the following (1)-(4):
  • the transverse elongation at break of the first base film is 50%-200%, and can be 60%-160%;
  • the longitudinal elongation at break of the first base film is 40%-700%, and can be optionally 80%-600%;
  • the transverse elongation at break of the second base film is 40%-220%, and can be optionally 80%-170%;
  • the longitudinal elongation at break of the second base film is 30%-100%, and can be optionally 40%-85%.
  • the puncture resistance of the separator is improved, thereby further improving the reliability of the secondary battery.
  • the average fiber diameter of the first base film is 60nm-300nm, optionally 80nm-200nm; and/or, the average fiber diameter of the second base film is 40nm-350nm, optionally 70nm-180nm.
  • the average fiber diameter of the first base film and/or the average fiber diameter of the second base film meet the above range, it helps to make the puncture strength of the base film and the separator within the scope of the present application, and also enables the separator to take into account good tensile properties, thereby further improving the reliability of the secondary battery.
  • the melting point of the first base film is 155°C-360°C, and can be 160°C-335°C; the melting point of the second base film is 125°C-260°C, and can be 130°C-220°C. Limiting the melting points of the first base film and the second base film to the above range can ensure that the first base film and the second base film have good puncture resistance while taking into account good heat resistance.
  • the relative molecular mass of the material of the first base film is 400,000-1.8 million, and can be 500,000-1.3 million. and/or the relative molecular mass of the material of the second base film is 300,000-1.5 million, optionally 400,000-1.1 million.
  • the isolation film has good puncture resistance, which can further improve the reliability of the secondary battery.
  • the thickness of the first base film is greater than or equal to the thickness of the second base film; optionally, the ratio of the thickness of the first base film to the thickness of the second base film is 1.02-5, preferably 1.1-3.0.
  • the thickness of the first base film is 2 ⁇ m-14 ⁇ m, and can be 3 ⁇ m-9 ⁇ m; the thickness of the second base film is 2 ⁇ m-12 ⁇ m, and can be 3 ⁇ m-7 ⁇ m.
  • the isolation film has better puncture resistance, which can further improve the reliability of the secondary battery and at the same time, can also increase the energy density of the battery.
  • an intermediate layer is further provided between the first base film and the second base film, the intermediate layer is provided between the first base film and the second base film, and the intermediate layer includes a binder; optionally, the intermediate layer also includes filler particles; optionally, the filler particles include at least one of inorganic particles, organic particles, and organic-metal framework materials.
  • the binder includes one or more of polyacrylate, polyacrylic acid, polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride-trichloroethylene copolymer, polyvinyl pyrrolidone, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyethylene oxide, polyarylate, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, polyacrylonitrile, polyvinyl alcohol, polyethylene, polypropylene, starch, and cyanoethyl pullulan.
  • the binder in the intermediate layer includes the above components, the reliability of the secondary battery can be improved.
  • the isolation film satisfies at least one of the following (1)-(5):
  • the puncture strength of the isolation film is 330gf-630gf, and can be 400gf-600gf;
  • the transverse tensile strength of the separator is ⁇ 700kg/cm 2 , and can be selected to be 1000kg/cm 2 -1900kg/cm 2 ;
  • the longitudinal tensile strength of the separator is ⁇ 1000kg/cm 2 , and can be selected to be 1200kg/cm 2 -2200kg/cm 2 ;
  • the longitudinal heat shrinkage rate of the isolation film at 250°C for 1 hour is ⁇ 3%, and can be optionally ⁇ 2.0%.
  • the separator When at least one of the above (1) to (5) of the separator satisfies the given range, the separator has good puncture resistance, thereby improving the reliability of the secondary battery.
  • the second aspect of the present application provides a secondary battery, which includes the separator according to the first aspect of the present application.
  • the secondary battery adopts the given separator, the reliability of the secondary battery can be improved.
  • the secondary battery further includes a positive electrode sheet and a negative electrode sheet, the separator is arranged between the positive electrode sheet and the negative electrode sheet, and the second base film of the separator faces the negative electrode sheet.
  • the second base film of the isolation film faces the negative electrode plate.
  • the second base film has high puncture strength, which can increase the effect of resisting lithium dendrite puncture and further improve the reliability of the secondary battery.
  • the third aspect of the present application provides an electric device, which includes the secondary battery of the second aspect of the present application.
  • the secondary battery of the electric device adopts the given isolation film, the reliability of the electric device can be improved.
  • the device of the present application includes the secondary battery provided by the present application, it has at least the same advantages as the secondary battery.
  • FIG. 1 is a schematic structural diagram of an isolation membrane according to an embodiment of the present application.
  • FIG. 2 is a schematic structural diagram of another embodiment of the isolation membrane of the present application.
  • FIG. 3 is a schematic diagram of an embodiment of a secondary battery.
  • FIG. 4 is an exploded view of FIG. 3 .
  • FIG. 5 is a schematic diagram of an embodiment of a battery module.
  • FIG. 6 is a schematic diagram of an embodiment of a battery pack.
  • FIG. 7 is an exploded view of FIG. 6 .
  • FIG. 8 is a schematic diagram of an embodiment of a device in which a secondary battery is used as a power source.
  • any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and any upper limit can be combined with any other upper limit to form an unspecified range.
  • each separately disclosed point or single value can itself be combined as a lower limit or upper limit with any other point or single value or with other lower limits or upper limits to form an unspecified range.
  • the term "or” is inclusive. That is, the phrase “A or (or) B” means “A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B”: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).
  • a secondary battery is a battery that can be recharged to activate the active materials after being discharged and continue to be used.
  • a secondary battery includes a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte.
  • active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet.
  • the separator is arranged between the positive electrode sheet and the negative electrode sheet to play a role of isolation.
  • the electrolyte plays a role of conducting ions between the positive electrode sheet and the negative electrode sheet.
  • an embodiment of the present application provides an isolation film 10, including a first base film 11 and a second base film 12, wherein the melting point of the second base film 12 is lower than that of the first base film 11; the puncture strength of the second base film 12 is 220gf-460gf, and the puncture strength of the isolation film 10 is 330gf-620gf.
  • the inventors have discovered through extensive research that in the separator of a specific structure of the present application, when the puncture strength of the second base film with a low melting point and the puncture strength of the separator are both within the above-mentioned specific range, the specific base film in the separator can be used to enhance the puncture resistance of the separator and improve the ability to resist dendrite penetration.
  • dendrite precipitation occurs on the negative electrode side, which requires higher puncture resistance of the separator, while the puncture resistance requirements toward the positive electrode side are relatively weak.
  • the positive electrode side may have higher requirements for other properties, such as heat resistance, to prevent thermal breakdown.
  • the second base film can be used to give full play to its excellent performance to The puncture resistance of the isolation membrane is enhanced, and the first base film is used to balance and regulate other properties of the isolation membrane, such as heat resistance, air permeability, and oxidation resistance, so that the overall performance of the isolation membrane is improved, thereby improving the reliability of the secondary battery.
  • the isolation membrane can optionally meet one or more of the following designs, the performance of the battery can be further improved.
  • the ratio of the puncture strength of the first base film 11 to the puncture strength of the second base film 12 is 0.2-0.95, and can be 0.3-0.75.
  • the ratio of the puncture strength of the first base film 11 to the puncture strength of the second base film 12 can be 0.2, 0.3, 0.32, 0.41, 0.48, 0.52, 0.54, 0.66, 0.71, 0.75, 0.85, 0.89, 0.92, 0.95, etc., or a range consisting of any two of the above values, for example, 0.2-0.32, 0.3-0.75, 0.41-0.54, 0.48-0.66, 0.71-0.89, 0.92-0.95, etc.
  • the puncture resistance and heat resistance of the first base film and the second base film can be taken into account, thereby further improving the reliability of the secondary battery.
  • the puncture strength of the first base film 11 is 100gf-220gf; and/or, the puncture strength of the second base film 12 is 260gf-400gf.
  • the puncture strength of the first base film 11 can be 100gf, 102gf, 114gf, 120gf, 126gf, 133gf, 139gf, 140gf, 164gf, 190gf, 220gf, etc., or a range consisting of any two of the above values, for example, 100gf-133gf, 90gf-114gf, 120gf-126gf, 133gf-164gf, 190gf-220gf, etc.
  • the puncture strength of the second base film 12 can be selected as 260gf, 267gf, 277gf, 300gf, 323gf, 339gf, 361gf, 370gf, 400gf, etc., or a range consisting of any two of the above values, for example, 260gf-300gf, 323gf-361gf, 361gf-400gf, etc.
  • the puncture resistance and heat resistance of the first base film and the second base film can be taken into account. While having good puncture resistance, it can also balance other properties, thereby improving the reliability of the secondary battery.
  • the puncture strength of the base film or isolation film has a well-known meaning in the art and can be tested using equipment and methods known in the art.
  • the puncture strength can be tested according to the standard: GB/T 10004-2008.
  • the sample to be tested can be cut into strips, wherein the width of the strip sample is 100 mm.
  • a test piece with a width of 100 mm is mounted on the sample film fixing clamp ring, and then a steel needle with a diameter of 1.0 mm and a top radius of 0.5 mm is used to puncture at a speed of (50 ⁇ 5) mm/min, and the maximum load of the steel needle penetrating the test piece is read.
  • 5 parallel test samples can be taken at the same time, and 3 points are measured for each test sample, and the arithmetic mean is taken as the final puncture strength.
  • the isolation film 10 satisfies at least one of the following (1)-(4):
  • the transverse elongation at break of the first base film 11 is 50%-200%, and can be 60%-160%;
  • the longitudinal elongation at break of the first base film 11 is 40%-700%, and can be 80%-600%;
  • the transverse elongation at break of the second base film 12 is 40%-220%, and can be optionally 80%-170%;
  • the longitudinal elongation at break of the second base film 12 is 30%-100%, and can be optionally 40%-85%.
  • the puncture resistance of the separator is improved, thereby further improving the reliability of the secondary battery.
  • the puncture strength of the basement membrane can be adjusted by adjusting the intrinsic parameters of the basement membrane (such as one or more of the average fiber diameter of the basement membrane, the relative molecular mass of the basement membrane material, etc.).
  • the swelling rate of the basement membrane can be adjusted by known methods within the range of parameters given in this application, such as adjusting the production process of the basement membrane (regulating the average fiber diameter of the basement membrane, the relative molecular mass of the basement membrane material, etc.), and obtain a basement membrane with the required puncture strength through a limited number of tests.
  • the average fiber filament diameter of the first basement membrane 11 is 60nm-300nm, and can be 80nm-200nm; and/or, the average fiber filament diameter of the second basement membrane 12 is 40nm-350nm, and can be 70nm-180nm.
  • the average fiber diameter of the first base film 11 can be 60nm, 70nm, 75nm, 80nm, 96nm, 100nm, 124nm, 140nm, 172nm, 189nm, 200nm, 216nm, 238nm, 250nm, 264nm, 270nm, 283nm, 300nm, etc., or a range consisting of any two of the above values, for example, 60nm-75nm, 70nm-100nm, 124nm-189nm, 172nm-238nm, 264nm-270nm, 283nm-300nm, etc.
  • the average fiber filament diameter of the first basement membrane 11 can be 80nm-200nm.
  • the average fiber diameter of the second base film 12 may be 40nm, 64nm, 70nm, 89nm, 100nm, 119nm, 142nm, 157nm, 180nm, 196nm, 224nm, 265nm, 274nm, 290nm, 300nm, 315nm, 324nm, 330nm, 339nm, 341nm, 350nm, etc., or a range consisting of any two of the above values, for example, 119nm-157nm, 157nm-196nm, 224nm-265nm, 274nm-315nm, 300nm-330nm, 330nm-341nm, 341nm-350nm, etc. In some embodiments, the average fiber diameter of the second base film 12 may be 70nm-100nm.
  • the average fiber diameter of the first base membrane and/or the average fiber diameter of the second base membrane meets the above range, it helps to make the puncture strength of the base membrane and the isolation membrane within the range of the present application, and also enables the isolation membrane to have good tensile properties, thereby further improving the reliability of the secondary battery.
  • the average fiber filament diameter of the basement membrane has a well-known meaning in the art and can be tested using known equipment and methods.
  • a scanning electron microscope such as ZEISS Sigma 300
  • JY/T010-1996 to obtain a scanning electron microscope (SEM) image of the basement membrane.
  • the melting point of the first base film 11 is 155°C-360°C, and can be 160°C-335°C; the melting point of the second base film 12 is 125°C-260°C, and can be 130°C-220°C.
  • the melting point of the first base film 11 can be 155°C, 159°C, 160°C, 170°C, 186°C, 190°C, 212°C, 235°C, 246°C, 264°C, 279°C, 281°C, 312°C, 345°C, 355°C, 360°C, etc., or a range consisting of any two of the above values, for example, 155°C-170°C, 186°C-212°C, 235°C-279°C, 160°C-335°C, 281°C-312°C, 345°C-360°C, etc.
  • the melting point of the second base film 12 is 125°C, 135°C, 153°C, 171°C, 196°C, 200°C, 224°C, 235°C, 260°C, etc., or a range consisting of any two of the above values, for example, 125°C-135°C, 153°C-196°C, 130°C-220°C, 196°C-200°C, 224°C-260°C, etc.
  • the melting points of the first base film and the second base film By limiting the melting points of the first base film and the second base film to the above ranges, it is possible to ensure that the first base film and the second base film have good puncture resistance while also having good heat resistance.
  • the melting points of the first base film and the second base film can be tested using equipment and methods known in the art.
  • differential scanning calorimetry can be used for determination.
  • the determination can be carried out according to the following method: take 4-6 mg of the sample to be tested, place it in the sample chamber of the differential scanning calorimeter, and heat it from 25°C to 400°C at a heating rate of 10°C/min to obtain the melting endothermic curve of the sample. The temperature corresponding to the peak of the curve is the melting point of the sample.
  • the relative molecular mass of the material of the first base film 11 is 400,000-1.8 million, and can be 500,000-1.3 million; and/or, the relative molecular mass of the material of the second base film 12 is 300,000-1.5 million, and can be 400,000-1.1 million.
  • the relative molecular mass of the material of the first base film 11 can be selected as 400,000, 450,000, 460,000, 550,000, 640,000, 750,000, 960,000, 1.2 million, 1.37 million, 1.45 million, 1.54 million, 1.62 million, 1.71 million, 1.74 million, 1.78 million, 1.8 million, etc., or a range consisting of any two of the above values, for example, 400,000-450,000, 450,000-750,000, 750,000-960,000, 1.2 million-1.37 million, 1.45 million-1.74 million, 1.74 million-1.78 million, 1.78 million-1.8 million, etc. In some embodiments, the relative molecular mass of the material of the first base film 11 can be 500,000-1.3 million.
  • the relative molecular mass of the material of the second base film 12 can be selected as 300,000, 390,000, 490,000, 570,000, 640,000, 660,000, 800,000, 970,000, 1.03 million, 1.14 million, 1.24 million, 1.38 million, 1.41 million, 1.44 million, 1.48 million, 1.5 million, etc., or a range consisting of any two of the above values, for example, 300,000-390,000, 570,000-660,000, 800,000-1.14 million, 1.14 million-1.44 million, 1.44 million-1.5 million, etc.
  • the relative molecular mass of the material of the second base film 12 can be 400,000-1.10 million.
  • the relative molecular mass of the base film material will affect the final film-forming state of the base film, and then affect the puncture strength of the base film.
  • the relative molecular mass of the material will also affect other properties of the material such as tensile strength.
  • the relative molecular mass of the base film has a well-known meaning in the art and can be tested using equipment and methods known in the art, for example, using a high temperature GPC test (differential refractive index detector) for testing.
  • GPC test differential refractive index detector
  • the thickness of the first base film 11 is greater than or equal to the thickness of the second base film 12; optionally, the ratio of the thickness of the first base film 11 to the thickness of the second base film 12 is 1.02-5, preferably 1.1-3.0. In some embodiments, the ratio of the thickness of the first base film 11 to the thickness of the second base film 12 can be 1.02, 1.1, 1.2, 1.4, 1.6, 2.2, 2.8, 3.0, 3.5, 3.9, 4.1, 4.4, 4.6, 4.8, 5, etc., or a range consisting of any two of the above values, for example, 1.02-1.2, 1.4-2.2, 2.8-3.5, 1.1-3.0, 3.9-4.4, 4.6-5, etc.
  • the thickness of the first base film 11 is 2 ⁇ m-14 ⁇ m, and can be 3 ⁇ m-9 ⁇ m; the thickness of the second base film 12 is 2 ⁇ m-12 ⁇ m, and can be 3 ⁇ m-7 ⁇ m.
  • the thickness of the first base film 11 may be 2 ⁇ m, 3.5 ⁇ m, 4 ⁇ m, 5 ⁇ m, 7 ⁇ m, 9 ⁇ m, 10 ⁇ m, 11 ⁇ m, 11.5 ⁇ m, 12 ⁇ m, 13.5 ⁇ m, 14 ⁇ m, etc., or a range of any two of the above values, for example, 2 ⁇ m-4 ⁇ m, 5 ⁇ m-10 ⁇ m, 10 ⁇ m-12 ⁇ m, 12 ⁇ m-14 ⁇ m, etc. In some embodiments, the thickness of the first base film 11 may be 3 ⁇ m-9 ⁇ m.
  • the thickness of the second base film 12 may be 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m, 10 ⁇ m, 11 ⁇ m, 12 ⁇ m, etc., or a range of any two of the above values, for example, 2 ⁇ m-4 ⁇ m, 5 ⁇ m-7 ⁇ m, 8 ⁇ m-9 ⁇ m, 10 ⁇ m-12 ⁇ m, etc. In some embodiments, the thickness of the second base film 12 may be 3 ⁇ m-7 ⁇ m.
  • the isolation film has better puncture resistance, thereby improving the reliability of the secondary battery and at the same time, increasing the energy density of the battery.
  • the thickness of the base film can be tested using equipment and methods known in the art.
  • a lithium battery separator thickness gauge is used to qualitatively measure the thickness of the base film. Tests are performed with reference to GB/T6672 "Mechanical measurement method for the determination of thickness of plastic films and sheets". Specifically, the following steps can be used: take six groups of parallel samples, use a micrometer thickness gauge to measure the thickness of each group of samples at different positions, measure at least 20 points for each group of samples, and take the average value of the thickness of the six groups of samples as the base film thickness.
  • the first base film 11 and the second base film 12 can be directly laminated by hot pressing.
  • the hot pressing temperature is 20°C-50°C.
  • an intermediate layer 13 is further provided between the first base film 11 and the second base film 12, and the intermediate layer 13 is provided between the first base film 11 and the second base film 12, and the intermediate layer 13 includes a binder.
  • the intermediate layer 13 also includes filler particles.
  • the filler particles include at least one of inorganic particles, organic particles, and organic-metal framework materials.
  • the binder includes polyacrylate, polyacrylic acid, polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride-trichloroethylene copolymer, polyvinyl pyrrolidone, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyethylene oxide, One or more of polyarylate, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, polyacrylonitrile, polyvinyl alcohol, polyethylene, polypropylene, starch, cyanoethyl pullulan.
  • the binder in the intermediate layer includes the above components, the reliability of the secondary battery can be improved.
  • the inorganic particles include one or more of inorganic particles having a dielectric constant of 5 or more, inorganic particles having ion conductivity but not storing ions, and inorganic particles capable of undergoing electrochemical reactions.
  • the inorganic particles having a dielectric constant of 5 or more may include at least one of boehmite, aluminum oxide, zinc oxide, silicon oxide, titanium oxide, zirconium oxide, barium oxide, calcium oxide, magnesium oxide, nickel oxide, tin oxide, cerium oxide, yttrium oxide, hafnium oxide, aluminum hydroxide, magnesium hydroxide, silicon carbide, boron carbide, aluminum nitride, silicon nitride, boron nitride, magnesium fluoride, calcium fluoride, barium fluoride, barium sulfate, magnesium aluminum silicate, lithium magnesium silicate, sodium magnesium silicate, bentonite, hectorite, zirconium titanate, barium titanate, Pb(Zr,Ti )O3 (abbreviated as PZT), Pb1- mLamZr1 - nTinO3 ( abbreviated as PLZT, 0 ⁇ m ⁇ 1, 0 ⁇ n ⁇ 1),
  • the modification method of each inorganic particle may be chemical modification and/or physical modification.
  • the chemical modification method includes coupling agent modification (for example, using silane coupling agent, titanate coupling agent, etc.), surfactant modification, polymer grafting modification, etc.
  • the physical modification method may be mechanical force dispersion, ultrasonic dispersion, high energy treatment, etc.
  • the modification treatment can reduce the agglomeration of inorganic particles, thereby enabling the bonding layer to have a more stable and uniform structure; in addition, by selecting a coupling agent, surfactant or polymer with a specific functional group to modify the inorganic particles, it is also helpful to improve the bonding layer's wetting and retention characteristics for the electrolyte, and improve the bonding of the bonding layer to the first base film and the second base film.
  • the inorganic particles having ion conductivity but not storing ions may include Li3PO4 , lithium titanium phosphate Lix1Tiy1 ( PO4 ) 3 , lithium aluminum titanium phosphate Lix2Aly2Tiz1 ( PO4 ) 3 , ( LiAlTiP) x3Oy3 type glass, lithium lanthanum titanate Lix4Lay4TiO3 , lithium germanium thiophosphate Lix5Gey5Pz2Sw , lithium nitride Lix6Ny6 , SiS2 type glass Lix7Siy7Sz3 and P2S5 type glass Lix8Py8S At least one of z4 , 0 ⁇ x1 ⁇ 2, 0 ⁇ y1 ⁇ 3, 0 ⁇ x2 ⁇ 2, 0 ⁇ y2 ⁇ 1, 0 ⁇ z1 ⁇ 3, 0 ⁇ x3 ⁇ 4, 0 ⁇ y3 ⁇ 13, 0 ⁇ x4 ⁇ 2, 0 ⁇ y4 ⁇ 3, 0 ⁇ x5 ⁇ 4,
  • the inorganic particles capable of undergoing an electrochemical reaction may include at least one of lithium-containing transition metal oxides, lithium-containing phosphates, carbon-based materials, silicon-based materials, tin-based materials, and lithium-titanium compounds.
  • the organic particles may include one or more of polycarbonate, polythiophene, polypyridine, polystyrene, polyacrylic wax, polyethylene, polypropylene, cellulose, a cellulose modifier (e.g., carboxymethyl cellulose), melamine resin, phenolic resin, polyester (e.g., polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate), silicone resin, polyimide, polyamideimide, polyaramid, polyphenylene sulfide, polysulfone, polyethersulfone, polyetheretherketone, polyaryletherketone, a copolymer of butyl acrylate and ethyl methacrylate (e.g., a cross-linked polymer of butyl acrylate and ethyl methacrylate).
  • polycarbonate polythiophene
  • polypyridine polystyrene
  • polyacrylic wax polyethylene
  • polypropylene cellulose
  • cellulose
  • the organic-metal framework material may include one or more of a nitrogen-containing heterocyclic ligand building structure, an organic carboxylic acid ligand building structure, and a nitrogen-oxygen mixed ligand building structure.
  • the content of the binder may be greater than or equal to 10%, optionally 10%-30%, based on the total weight of the adhesive layer.
  • the content of the filler may be less than or equal to 90%, optionally 40%-90%, 60%-80%, based on the total weight of the adhesive layer.
  • the middle layer may further include a dispersant, such as carboxymethyl cellulose, so as to adjust the viscosity of the middle layer slurry and improve the quality and uniformity of the middle layer.
  • a dispersant such as carboxymethyl cellulose
  • the content of the dispersant may be less than or equal to 25%, and may be less than or equal to 20%, based on the adhesive layer. Total weight.
  • the isolation film 10 satisfies at least one of the following (1)-(5):
  • the puncture strength of the isolation film is 330gf-630gf, and can be 400gf-600gf;
  • the transverse tensile strength of the separator is ⁇ 700kg/cm 2 , and can be selected to be 1000kg/cm 2 -1900kg/cm 2 ;
  • the longitudinal tensile strength of the separator is ⁇ 1000kg/cm 2 , and can be selected to be 1200kg/cm 2 -2200kg/cm 2 ;
  • the transverse heat shrinkage rate of the isolation film 10 at 250° C. for 1 hour is ⁇ 3%, and can be optionally ⁇ 2.0%;
  • the longitudinal heat shrinkage rate of the isolation film 10 at 250° C. for 1 hour is ⁇ 3%, and can be optionally ⁇ 2.0%.
  • the separator When at least one of the above (1) to (5) of the separator satisfies the given range, the separator has good puncture resistance, thereby improving the reliability of the secondary battery.
  • transverse tensile strength, longitudinal tensile strength, transverse heat shrinkage rate and longitudinal heat shrinkage rate of the base film or the isolation film have well-known meanings in the art and can be tested using equipment and methods known in the art. For example, the test can be performed with reference to standard GB/T36363-2018.
  • all raw materials used in the isolation film eg, the first base film, the second base film, the adhesive, the filler, etc.
  • the isolation film e.g., the first base film, the second base film, the adhesive, the filler, etc.
  • a positive electrode sheet generally includes a positive electrode current collector and a positive electrode film layer disposed on the positive electrode current collector, wherein the positive electrode film layer includes a positive electrode active material.
  • the positive electrode current collector may be a conventional metal foil or a composite current collector (a metal material may be disposed on a polymer substrate to form a composite current collector).
  • the positive electrode current collector may be an aluminum foil.
  • the positive electrode active material There is no limitation on the specific type of the positive electrode active material. Any active material known in the art that can be used for the positive electrode of a secondary battery can be used. Those skilled in the art can select the material according to actual needs.
  • the positive electrode active material may include, but is not limited to, one or more of lithium transition metal oxides, lithium-containing phosphates of olivine structure and their respective modified compounds.
  • lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide and their modified compounds.
  • lithium-containing phosphates of olivine structure may include, but are not limited to, one or more of lithium iron phosphate, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, a composite material of lithium iron manganese phosphate and carbon and their modified compounds. These materials can all be obtained through commercial channels.
  • the modified compounds of the above materials may be doping-modified and/or surface-coated modified materials.
  • the positive electrode film layer usually optionally includes a binder, a conductive agent and other optional auxiliary agents.
  • the conductive agent can be one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, conductive carbon black (Super P, SP), graphene and carbon nanofibers.
  • the binder can be one or more of Polymerized Styrene Butadiene Rubber (SBR), water-based acrylic resin, Polyvinylidene Difluoride (PVDF), Polytetrafluoroethylene (PTFE), Ethylene-vinyl Acetate Copolymer (EVA), Polyacrylic Acid (PAA), Carboxymethyl Cellulose (CMC), Polyvinyl Alcohol (PVA) and Polyvinyl Butyral (PVB).
  • SBR Polymerized Styrene Butadiene Rubber
  • PVDF Polyvinylidene Difluoride
  • PTFE Polytetrafluoroethylene
  • EVA Ethylene-vinyl Acetate Copolymer
  • PAA Polyacrylic Acid
  • CMC Carboxymethyl Cellulose
  • PVA Polyvinyl Alcohol
  • PVB Polyvinyl Butyral
  • a negative electrode plate generally includes a negative electrode current collector and a negative electrode film layer disposed on the negative electrode current collector, wherein the negative electrode film layer includes a negative electrode active material.
  • the negative electrode current collector may be a conventional metal foil or a composite current collector (for example, a metal material may be disposed on a polymer substrate to form a composite current collector).
  • the negative electrode current collector may be a copper foil.
  • the negative electrode active material may include, but is not limited to, one or more of artificial graphite, natural graphite, hard carbon, soft carbon, silicon-based materials and tin-based materials.
  • Silicon-based materials can be selected from one or more of elemental silicon, silicon oxide compounds (such as silicon monoxide), silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.
  • Tin-based materials can be selected from one or more of elemental tin, tin oxide compounds, and tin alloys. These materials can all be obtained commercially.
  • the negative electrode active material may include a silicon-based material.
  • the negative electrode film layer usually optionally includes a binder, a conductive agent and other optional auxiliary agents.
  • the conductive agent may be one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the binder can be one or more of styrene-butadiene rubber (SBR), water-based acrylic resin, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyvinyl alcohol (PVA) and polyvinyl butyral (PVB).
  • SBR styrene-butadiene rubber
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • EVA ethylene-vinyl acetate copolymer
  • PVA polyvinyl alcohol
  • PVB polyvinyl butyral
  • auxiliary agents may be thickening and dispersing agents (e.g. sodium carboxymethyl cellulose
  • Carboxymethylcellulose Sodium, CMC-Na), PTC thermistor materials are Carboxymethylcellulose Sodium, CMC-Na), PTC thermistor materials.
  • the secondary battery may include an electrolyte that conducts ions between the positive electrode and the negative electrode.
  • the electrolyte may include an electrolyte salt and a solvent.
  • the electrolyte salt can be selected from one or more of lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium perchlorate (LiClO 4 ), lithium hexafluoroarsenate (LiAsF 6 ), lithium bisfluorosulfonyl imide (LiFSI), lithium bistrifluoromethanesulfonyl imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalatoborate (LiDFOB), lithium bisoxalatoborate (LiBOB), lithium difluorophosphate (LiPO 2 F 2 ), lithium difluorobisoxalatophosphate (LiDFOP) and lithium tetrafluorooxalatophosphate (LiTFOP).
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium perchlor
  • the solvent can be selected from ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl 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), One or more of methyl acetate (Methyl Acetate, MA), ethyl acetate (Ethyl Acetate, EA), propyl acetate (n-Propyl Acetate, PA), methyl propionate (Methyl Propionate, MP), ethyl propionate (Ethyl Propanoate, EP), propyl propionate (n-Propyl Propionate, PP), methyl butyrate (Methyl Butyrate MB), ethyl butyrate (Ethyl but
  • the electrolyte further includes additives, such as additives that may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high temperature performance, and additives that improve battery low temperature performance.
  • additives such as additives that may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high temperature performance, and additives that improve battery low temperature performance.
  • the secondary battery may be a lithium ion secondary battery.
  • the second base film 12 of the separator 10 faces the negative electrode.
  • the second base film 12 of the separator 10 faces the negative electrode plate.
  • the second base film 12 has high puncture strength, which can increase the effect of resisting lithium dendrite puncture and improve the reliability of the secondary battery.
  • FIG3 is a secondary battery 5 of a square structure as an example.
  • the secondary battery may include an outer package for packaging a positive electrode sheet, a negative electrode sheet, and an electrolyte.
  • the outer packaging of the secondary battery can be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell.
  • the outer packaging of the secondary battery can also be a soft package, such as a bag-type soft package.
  • the material of the soft package can be plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).
  • the outer package may include a shell 51 and a cover plate 53.
  • the shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity.
  • the shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity.
  • the positive electrode sheet, the separator 10, the negative electrode sheet and the electrolyte can be assembled to form a secondary battery.
  • the positive electrode sheet, the separator 10, and the negative electrode sheet can be formed into an electrode assembly through a winding process and/or a lamination process, and the electrode assembly is placed in an outer package, and the electrolyte is injected after drying. After vacuum packaging, standing, formation, shaping and other processes, a battery cell is obtained.
  • Multiple battery cells can also be further connected in series, in parallel or in mixed connection to form a battery module.
  • Multiple battery modules can also be connected in series, in parallel or in mixed connection to form a battery pack. In some embodiments, multiple battery cells can also directly form a battery pack.
  • FIG5 is a battery module 4 as an example.
  • a plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4. Of course, they may also be arranged in any other manner. Further, the plurality of secondary batteries 5 may be fixed by fasteners.
  • the battery module 4 may further include a housing having a housing space in which the plurality of secondary batteries 5 are housed.
  • the battery modules described above may also be assembled into a battery pack, and the number of battery modules contained in the battery pack may be adjusted according to the application and capacity of the battery pack.
  • FIG6 and FIG7 are battery packs 1 as an example.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box.
  • the battery box includes an upper box body 2 and a lower box body 3, and the upper box body 2 can be covered on the lower box body 3 to form a closed space for accommodating the battery modules 4.
  • the plurality of battery modules 4 can be arranged in the battery box in any manner.
  • the present application also provides an electrical device, which includes the secondary battery of the present application.
  • the battery cell, battery module or battery pack can be used as a power source for the device, or as an energy storage unit for the device.
  • the device can be, but is not limited to, a mobile device (such as a mobile phone, a laptop computer), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck), an electric train, a ship and a satellite, and an energy storage system.
  • the device can select battery cells, battery modules or battery packs according to its usage requirements.
  • FIG8 is an example of an electric device.
  • the electric device may be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • a battery pack or a battery module may be used.
  • the electric device may be a mobile phone, a tablet computer, or a notebook computer.
  • the electric device is usually required to be thin and light, and a battery cell may be used as a power source.
  • the first base film is polypropylene (PP), and the second base film is polyethylene (PE), wherein the melting point of the first base film is 165°C, and the melting point of the second base film is 135°C.
  • the transverse elongation at break of the first base film is 60%, and the longitudinal elongation at break is 80%.
  • the transverse elongation at break of the second base film is 130%, and the longitudinal elongation at break is 75%.
  • the puncture strength P1 of the first base film is 120gf, and the puncture strength P2 of the second base film is 300gf; wherein the ratio P1/P2 of the puncture strength P1 of the first base film to the puncture strength P2 of the second base film is 0.40.
  • step (3) The intermediate layer slurry of step (2) is coated on one side of the second base film of step (1) to form an intermediate layer.
  • the first base film is laminated with the second base film coated in step (3) by hot pressing to obtain a separator, wherein the intermediate layer is between the first base film and the second base film.
  • the preparation method of the isolation film 2-11 is similar to that of the isolation film 1, except that one or more of the melting point, material, transverse elongation at break, longitudinal elongation at break, and puncture strength of the first base film or the second base film is adjusted, as shown in Table 1.
  • the other preparation methods are consistent with the preparation method of the isolation film of Example 1.
  • the positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), the conductive agent carbon black (SuperP), and the binder polyvinylidene fluoride (PVDF) are uniformly mixed in a proper amount of solvent N-methylpyrrolidone (NMP) at a mass ratio of 96.2:2.7:1.1 to obtain a positive electrode slurry, and the positive electrode slurry is coated on a positive electrode current collector aluminum foil, and the positive electrode sheet is obtained through drying, cold pressing, slitting, and cutting processes.
  • NMP solvent N-methylpyrrolidone
  • the negative electrode active material artificial graphite, the conductive agent carbon black (SuperP), the binder styrene-butadiene rubber (SBR) and sodium carboxymethyl cellulose (CMC-Na) are mixed uniformly in a proper amount of solvent deionized water at a mass ratio of 96.4:0.7:1.8:1.1 to obtain a negative electrode slurry, and the negative electrode slurry is coated on the negative electrode current collector copper foil, and the negative electrode sheet is obtained through the processes of drying, cold pressing, slitting and cutting.
  • the isolation film adopts the isolation film 1 prepared above.
  • Ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed at a mass ratio of 30:70 to obtain an organic solvent, and fully dried electrolyte salt LiPF 6 is dissolved in the mixed solvent, the concentration of the electrolyte salt is 1.0 mol/L, and the mixture is evenly mixed to obtain an electrolyte solution.
  • the positive electrode sheet, the isolation film, and the negative electrode sheet are stacked in order, so that the isolation film is placed between the positive electrode sheet and the negative electrode sheet to play an isolating role, wherein the second base film faces the negative electrode sheet, and then wound to obtain an electrode assembly; the electrode assembly is placed in an outer package, and the prepared electrolyte is injected into the dried secondary battery. After vacuum packaging, standing, formation, and shaping processes, a secondary battery is obtained.
  • the battery was tested at 25°C and 100% SOC, with the temperature-sensing wires arranged in the order of positive pole/negative pole/large surface center (5mm above the puncture hole)/large surface center back/cell explosion-proof valve, and the voltage wires arranged in the order of V positive and negative/V positive needle/V negative needle, with the multi-channel acquisition frequency ⁇ 0.1S; a ⁇ 1mm high-temperature resistant steel needle (the cone angle of the needle tip is 30°) was used, aimed at the center of the large surface of the cell, and the puncture speed was 0.01mm/s; the needle was punctured to the positive pole until the voltage reached 0.5V, and the puncture depth was continued to 3mm for 1h, and the value displayed on the instrument display was observed. If the voltage was normal and there was no fluctuation, it was normal and not out of control, and it was recorded as PASS; if the voltage fluctuation was abnormal and the cell failed, it was recorded as NP.
  • the secondary battery prepared in the embodiment and the comparative example is charged at a constant current of 1C to a charge cut-off voltage V1, then charged at a constant voltage to a current ⁇ 0.05C, left to stand for 5 minutes, and then discharged at a constant current of 0.33C to a discharge cut-off voltage V2, left to stand for 5 minutes.
  • This is a charge and discharge cycle.
  • the battery is subjected to a cyclic charge and discharge test according to this method until the battery capacity decays to 80%. The number of cycles at this time is the cycle life of the battery at 25°C.
  • Examples 1-9 a comparison analysis is conducted between Examples 1-9 and Comparative Examples 1-2.
  • the melting point of the second base film is lower than that of the first base film
  • the puncture strength of the second base film is 220gf-460gf
  • the puncture strength of the isolation film is 330gf-620gf.
  • the battery using the isolation film of the present application can not only pass the shallow puncture test, but also increase the number of cycles. That is, under the same battery performance standard, the battery prepared using the isolation film provided by the present application has higher reliability.

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Abstract

本申请提供一种隔离膜，其包括：第一基膜和第二基膜，第二基膜的熔点低于第一基膜的熔点；第二基膜的穿刺强度为220gf-460gf，隔离膜的穿刺强度为330gf-620gf。当第一基膜和隔离膜的穿刺强度在上述选定范围时，可以提高二次电池的可靠性。

Description

隔离膜、二次电池和用电装置 技术领域
本申请属于二次电池技术领域，具体涉及一种隔离膜、二次电池和用电装置。
背景技术
二次电池因具有重量轻、无污染、无记忆效应突出特点，被广泛应用于各类消费类电子产品和电动车辆中。随着新能源行业的不断发展，用户对二次电池可靠性能提出了更高的使用需求。
因此，如何使二次电池具有更好的可靠性是目前亟待解决的问题。
发明内容
鉴于背景技术中存在的技术问题，本申请提供一种隔离膜、二次电池和用电装置，旨在提高二次电池的可靠性。
为了实现上述目的，本申请的第一方面提供一种隔离膜，其包括：第一基膜和第二基膜，第二基膜的熔点低于第一基膜的熔点；第二基膜的穿刺强度为220gf-460gf，隔离膜的穿刺强度为330gf-620gf。
相对于现有技术，本申请至少包括如下的有益效果：本申请所提供的隔离膜，通过设置第二基膜的熔点低于第一基膜的熔点，且第二基膜的穿刺强度和隔离膜的穿刺强度选定在上述范围，使得隔离膜具有不同程度的耐穿刺能力，即一侧的耐穿刺能力与另一侧耐穿刺能力不同，在应对电池中枝晶不均匀时，能够防止枝晶穿透隔离膜而导致短路，从而可以提高二次电池的可靠性。
在本申请任意实施方式中，第一基膜的穿刺强度和第二基膜的穿刺强度的比值为0.2-0.95，可选为0.3-0.75。当第一基膜的穿刺强度和第二基膜的穿刺强度之比满足上述条件时，使得隔离膜具有良好的耐穿刺性能的同时，还能够平衡其他性能，从而可以进一步提高二次电池的可靠性。
在本申请任意实施方式中，第一基膜的穿刺强度为100gf-220gf；第二基膜的穿刺强度为260gf-400gf。当第一基膜的穿刺强度和/或第二基膜的穿刺强度满足上述条件时，使得隔离膜具有良好的耐穿刺性能，可以进一步提高二次电池的可靠性。
在本申请任意实施方式中，隔离膜满足下述(1)-(4)中的至少一个：
(1)第一基膜的横向断裂伸长率为50％-200％，可选为60％-160％；
(2)第一基膜的纵向断裂伸长率为40％-700％，可选为80％-600％；
(3)第二基膜的横向断裂伸长率为40％-220％，可选为80％-170％；
(4)第二基膜的纵向断裂伸长率为30％-100％，可选为40％-85％。
当隔离膜上述(1)-(4)中至少一项满足所给的范围时，使得隔离膜的耐穿刺性能更佳，从而进一步提高二次电池的可靠性。
在本申请任意实施方式中，第一基膜的平均纤维丝直径为60nm-300nm，可选为80nm-200nm；和/或，第二基膜的平均纤维丝直径为40nm-350nm，可选为70nm-180nm。当第一基膜的平均纤维丝直径和/或第二基膜的平均纤维丝直径满足上述范围时，有助于使得基膜和隔离膜的穿刺强度在本申请的范围内，而且还能使隔离膜兼顾良好的拉伸性能，从而进一步提高二次电池的可靠性。
在本申请任意实施方式中，第一基膜的熔点为155℃-360℃，可选为160℃-335℃；第二基膜的熔点为125℃-260℃，可选为130℃-220℃。将第一基膜的熔点与第二基膜的熔点限定在以上的范围内，能够在确保第一基膜和第二基膜具有较好耐穿刺性能的同时，兼顾较好的耐热性。
在本申请任意实施方式中，第一基膜的材料的相对分子质量为40万-180万，可选为50万-130 万；和/或，第二基膜的材料的相对分子质量为30万-150万，可选为40万-110万。当第一基膜的相对分子质量和第二基膜的相对分子质量满足上述条件时，使得隔离膜具有良好的耐穿刺性能，可以进一步提高二次电池的可靠性。
在本申请任意实施方式中，第一基膜的厚度大于等于第二基膜的厚度；可选地，第一基膜的厚度和第二基膜的厚度之比为1.02-5，优选为1.1-3.0。
在本申请任意实施方式中，第一基膜的厚度为2μm-14μm，可选为3μm-9μm；第二基膜的厚度为2μm-12μm，可选为3μm-7μm。
当第一基膜的厚度和/或第二基膜的厚度满足上述条件时，使得隔离膜具有更佳的耐穿刺性能，从而可以进一步提高二次电池的可靠性，同时，还可以提升电池的能量密度。
在本申请任意实施方式中，第一基膜和第二基膜之间还设置有中间层，中间层设置在第一基膜和第二基膜之间，中间层包括粘结剂；可选地，中间层还包括填充颗粒；可选地，填充颗粒包括无机颗粒、有机颗粒、有机-金属框架材料中的至少一种。当第一基膜和第二基膜之间设置有中间层时，不仅能补偿热压复合过程中的工艺缺陷，同时，能够进一步改善隔离膜的物理性质稳定，从而进一步提高二次电池的可靠性。
在本申请任意实施方式中，粘结剂包括聚丙烯酸酯、聚丙烯酸、聚四氟乙烯、聚偏氟乙烯、偏氟乙烯-三氯乙烯共聚物、聚乙烯吡咯烷酮、聚乙酸乙烯酯、乙烯-乙酸乙烯酯共聚物、聚环氧乙烷、聚芳酯、羧甲基纤维素、羟丙基纤维素、再生纤维素、乙酸纤维素、乙酸丙酸纤维素、乙酸丁酸纤维素、聚丙烯腈、聚乙烯醇、聚乙烯、聚丙烯、淀粉、氰基乙基支链淀粉中的一种或几种。当第一基膜和第二基膜之间设置有中间层，且中间层中的粘结剂包括以上组分时，能够提高二次电池的可靠性。
在本申请任意实施方式中，隔离膜满足下述(1)-(5)中的至少一项：
(1)隔离膜的穿刺强度为330gf-630gf，可选为400gf-600gf；
(2)隔离膜的横向拉伸强度≥700kg/cm2，可选为1000kg/cm2-1900kg/cm2；
(3)隔离膜的纵向拉伸强度≥1000kg/cm2，可选为1200kg/cm2-2200kg/cm2；
(4)隔离膜在250℃、1h下的横向热收缩率为≤3％，可选为≤2.0％；
(5)隔离膜在250℃、1h下的纵向热收缩率为≤3％，可选≤2.0％。
当隔离膜上述(1)-(5)中至少一项满足所给的范围时，使得隔离膜具有良好的耐穿刺性能，从而可以提高二次电池的可靠性。
本申请的第二方面提供一种二次电池，其包括根据本申请第一方面的隔离膜，当二次电池采用所给的隔离膜时，可提高二次电池的可靠性。
在本申请任意实施方式中，二次电池还包括正极极片和负极极片，隔离膜设置在正极极片和负极极片之间，隔离膜的第二基膜朝向负极极片。
隔离膜的第二基膜朝向负极极片，第二基膜的穿刺强度高，可以增加抗锂枝晶刺破的效果，进一步提高二次电池的可靠性。
本申请的第三方面提供一种用电装置，其包括本申请第二方面的二次电池。当用电装置的二次电池采用所给的隔离膜时，可提高用电装置的可靠性。
由于本申请的装置包括本申请提供的二次电池，因而至少具有与二次电池相同的优势。
附图说明
为了更清楚地说明本申请的技术方案，下面将对本申请中所使用的附图作简单介绍。显而易见 地，下面所描述的附图仅仅是本申请的一些实施方式，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
图1是本申请隔离膜的一实施方式的结构示意图。
图2是本申请隔离膜的另一实施方式的结构示意图。
图3是二次电池的一实施方式的示意图。
图4是图3的分解图。
图5是电池模块的一实施方式的示意图。
图6是电池包的一实施方式的示意图。
图7是图6的分解图。
图8是二次电池用作电源的装置的一实施方式的示意图。
具体实施方式
下面结合具体实施方式，进一步阐述本申请。应理解，这些具体实施方式仅用于说明本申请而不用于限制本申请的范围。
为了简明，本文仅具体地公开了一些数值范围。然而，任意下限可以与任意上限组合形成未明确记载的范围；以及任意下限可以与其它下限组合形成未明确记载的范围，同样任意上限可以与任意其它上限组合形成未明确记载的范围。此外，每个单独公开的点或单个数值自身可以作为下限或上限与任意其它点或单个数值组合或与其它下限或上限组合形成未明确记载的范围。
在本文的描述中，除非另有说明，术语“或(or)”是包括性的。也就是说，短语“A或(or)B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B都为真(或存在)。
在本文的描述中，需要说明的是，除非另有说明，“以上”、“以下”为包括本数，“一种或几种”中“几种”的含义是两种及两种以上。
除非另有说明，本申请中使用的术语具有本领域技术人员通常所理解的公知含义。除非另有说明，本申请中提到的各参数的数值可以用本领域常用的各种测量方法进行测量(例如，可以按照在本申请的实施例中给出的方法进行测试)。
二次电池
二次电池，是指在电池放电后可通过充电的方式使活性材料激活而继续使用的电池。
通常情况下，二次电池包括正极极片、负极极片、隔离膜及电解质。在电池充放电过程中，活性离子在正极极片和负极极片之间往返嵌入和脱出。隔离膜设置在正极极片和负极极片之间，起到隔离的作用。电解质在正极极片和负极极片之间起到传导离子的作用。
[隔离膜]
参阅图1，本申请实施例提供一种隔离膜10，包括第一基膜11和第二基膜12，第二基膜12的熔点低于第一基膜11的熔点；第二基膜12的穿刺强度为220gf-460gf，隔离膜10的穿刺强度为330gf-620gf。
不希望限于任何理论，发明人经大量研究发现，在本申请特定结构的隔离膜中，当熔点低的第二基膜的穿刺强度和隔离膜的穿刺强度均在上述特定的范围内时，则可以利用隔离膜中的特定基膜增强隔离膜的耐穿刺性能，提高抗枝晶穿破的能力。一般地，枝晶析出发生在负极侧，对隔离膜耐穿刺性能的要求更高，而朝向正极侧的耐穿刺性能需求相对较弱，然而正极侧可能对其他性能要求更高，例如耐热性，以防止热击穿。因此，可以利用第二基膜发挥其优异的性能，以 增强隔离膜的耐穿刺性能，利用第一基膜平衡调控隔离膜的其他性能，例如调控耐热性、透气性、抗氧化性等，使得隔离膜的整体性能得到提升，从而可以提高二次电池的可靠性。
发明人经过进一步研究发现，如果隔离膜还可选的满足下述设计中的一个或多个时，可以进一步改善电池的性能。
在本申请任意实施方式中，第一基膜11的穿刺强度和第二基膜12的穿刺强度的比值为0.2-0.95，可选为0.3-0.75。例如，第一基膜11的穿刺强度和第二基膜12的穿刺强度的比值可选为0.2、0.3、0.32、0.41、0.48、0.52、0.54、0.66、0.71、0.75、0.85、0.89、0.92、0.95等，或是上述任意两个数值组成的范围，例如，0.2-0.32、0.3-0.75，0.41-0.54、0.48-0.66、0.71-0.89、0.92-0.95等。当第一基膜的穿刺强度和第二基膜的穿刺强度之比满足上述条件时，第一基膜和第二基膜的耐穿刺性能和耐热性能可以兼顾，从而可以进一步改善二次电池的可靠性。
在本申请任意实施方式中，第一基膜11的穿刺强度为100gf-220gf；和/或，第二基膜12的穿刺强度为260gf-400gf。例如，第一基膜11的穿刺强度可选为100gf、102gf、114gf、120gf、126gf、133gf、139gf、140gf、164gf、190gf、220gf等，或是上述任意两个数值组成的范围，例如，100gf-133gf、90gf-114gf、120gf-126gf、133gf-164gf、190gf-220gf等。第二基膜12的穿刺强度可选为260gf、267gf、277gf、300gf、323gf、339gf、361gf、370gf、400gf等，或是上述任意两个数值组成的范围，例如，260gf-300gf、323gf-361gf、361gf-400gf等。当第一基膜的穿刺强度和/或第二基膜的穿刺强度满足上述条件时，第一基膜和第二基膜的耐穿刺性能和耐热性能可以兼顾。具有良好的耐穿刺性能的同时，还能够平衡其他性能，从而可以提高二次电池的可靠性。
基膜或隔离膜的穿刺强度具有本领域公知的含义，可以采用本领域已知的设备和方法进行测试。例如，穿刺强度可以依据标准：GB/T 10004-2008进行测试。具体的，可以将待测样品裁成条状，其中条状样品的宽度为100mm。将宽度为100mm的试片安装在样膜固定夹环上，然后用直径1.0mm，直径顶端半径为0.5mm的钢针，以(50±5)mm/min的速度进行顶刺，读取钢针穿透试片的最大载荷。通常可同时取5个平行测试样品，每个测试样品测3个点，取其算术平均值作为最终的穿刺强度。
在本申请任意实施方式中，隔离膜10满足下述(1)-(4)中的至少一个：
(1)第一基膜11的横向断裂伸长率为50％-200％，可选为60％-160％；(2)第一基膜11的纵向断裂伸长率为40％-700％，可选为80％-600％；
(3)第二基膜12的横向断裂伸长率为40％-220％，可选为80％-170％；
(4)第二基膜12的纵向断裂伸长率为30％-100％，可选为40％-85％。
当隔离膜上述(1)-(4)中至少一项满足所给的范围时，使得隔离膜的耐穿刺性能更佳，从而进一步提高二次电池的可靠性。
本领域的技术人员知晓，基膜的穿刺强度可以通过调节基膜的本征参数(例如基膜的平均纤维丝直径、基膜材料的相对分子质量等中的一者或者多者)来调整大小。本领域的技术人员可以在本申请所给的各参数范围内，通过已知的方法来调节基膜的溶胀率，例如调整基膜的生产工艺(调控基膜的平均纤维丝直径、基膜材料的相对分子质量等)，通过有限次试验即可得到所需穿刺强度大小的基膜。
在本申请任意实施方式中，第一基膜11的平均纤维丝直径为60nm-300nm，可选为80nm-200nm；和/或，第二基膜12的平均纤维丝直径为40nm-350nm，可选为70nm-180nm。
第一基膜11的平均纤维丝直径可以为60nm、70nm、75nm、80nm、96nm、100nm、 124nm、140nm、172nm、189nm、200nm、216nm、238nm、250nm、264nm、270nm、283nm、300nm等，或是上述任意两个数值组成的范围，例如，60nm-75nm、70nm-100nm、124nm-189nm、172nm-238nm、264nm-270nm、283nm-300nm等。在一些实施例中，第一基膜11的平均纤维丝直径可以为80nm-200nm。
第二基膜12的平均纤维丝直径可以为40nm、64nm、70nm、89nm、100nm、119nm、142nm、157nm、180nm、196nm、224nm、265nm、274nm、290nm、300nm、315nm、324nm、330nm、339nm、341nm、350nm等，或是上述任意两个数值组成的范围，例如，119nm-157nm、157nm-196nm、224nm-265nm、274nm-315nm、300nm-330nm、330nm-341nm、341nm-350nm等。在一些实施例中，第二基膜12的平均纤维丝直径可以为70nm-100nm。
当第一基膜的平均纤维丝直径和/或第二基膜的平均纤维丝直径满足上述范围时，有助于使得基膜和隔离膜的穿刺强度在本申请的范围内，而且还能使隔离膜兼顾良好的拉伸性能，从而进一步提高二次电池的可靠性。
基膜的平均纤维丝直径具有本领域公知的含义，可以采用已知的设备和方法进行测试。例如，采用扫描电子显微镜(例如ZEISS Sigma 300)，参考JY/T010-1996，获取基膜的扫描电子显微镜(SEM)图片。具体的，在基膜上任意选取一个长×宽＝5mm×5mm的测试样品，在测试样品中随机选取多个测试区域(例如5个)，并在一定放大倍率(例如10K倍)至清晰观测到纤维直径，用量尺选择多个位置(例如至少30个)进行测量，求取多个纤维丝直径的平均值，即为基膜的平均纤维丝直径。
在本申请任意实施方式中，第一基膜11的熔点为155℃-360℃，可选为160℃-335℃；第二基膜12的熔点为125℃-260℃，可选为130℃-220℃。
第一基膜11的熔点可以为155℃、159℃、160℃、170℃、186℃、190℃、212℃、235℃、246℃、264℃、279℃、281℃、312℃、345℃、355℃、360℃等，或是上述任意两个数值组成的范围，例如，155℃-170℃、186℃-212℃、235℃-279℃、160℃-335℃、281℃-312℃、345℃-360℃等。
第二基膜12的熔点为125℃、135℃、153℃、171℃、196℃、200℃、224℃、235℃、260℃等，或是上述任意两个数值组成的范围，例如，125℃-135℃、153℃-196℃、130℃-220℃、196℃-200℃、224℃-260℃等。
将第一基膜的熔点与第二基膜的熔点限定在以上的范围内，能够在确保第一基膜和第二基膜具有较好耐穿刺性能的同时，兼顾较好的耐热性。
第一基膜和第二基膜的熔点可以采用本领域已知的设备和方法进行测试。例如，可采用差示扫描量热法进行测定。具体可参考标准GB/T 19466.3-2004。作为示例，可按照如下方法进行测定：取4-6mg待测样品，置于差示扫描量热仪的样品室，温度从25℃升温至400℃，升温速率为10℃/min，得到样品的熔融吸热曲线，曲线峰值对应的温度为样品的熔点。
在本申请任意实施方式中，第一基膜11的材料的相对分子质量为40万-180万，可选为50万-130万；和/或，第二基膜12的材料的相对分子质量为30万-150万，可选为40万-110万。
第一基膜11的材料的相对分子质量可选为40万、45万、46万、55万、64万、75万、96万、120万、137万、145万、154万、162万、171万、174万、178万、180万等，或是上述任意两个数值组成的范围，例如，40万-45万、45万-75万、75万-96万、120万-137万、145万-174万、174万-178万、178万-180万等。在一些实施例中，第一基膜11的材料的相对分子质量可以为50万-130万。
第二基膜12的材料的相对分子质量可选为30万、39万、49万、57万、64万、66万、80万、97万、103万、114万、124万、138万、141万、144万、148万、150万等，或是上述任意两个数值组成的范围，例如，30万-39万、57万-66万、80万-114万、114万-144万、144万-150万等。在一些实施例中，第二基膜12的材料的相对分子质量可以为40万-110万。
其中，基膜材料的相对分子质量大小会影响基膜最终成膜的状态，进而会影响基膜的穿刺强度。材料的相对分子质量除了会影响基膜的穿刺强度外，还会影响材料的拉伸强度等其他性能。通过将第一基膜的材料的相对分子质量与第二基膜的材料的相对分子质量限定在以上范围，能够进一步提高第一基膜的穿刺强度，从而减少锂枝晶的穿刺概率，以及能够提高第一基膜对第二基膜的支撑力度，从而可以提高二次电池的可靠性。
基膜的相对分子质量具有本领域公知的含义，可以采用本领域已知的设备和方法进行测试。例如，采用高温GPC测试(示差折光检测器)进行测试。
在本申请任意实施方式中，第一基膜11的厚度大于等于第二基膜12的厚度；可选地，第一基膜11的厚度和第二基膜12的厚度之比为1.02-5，优选为1.1-3.0。在一些实施例中，第一基膜11的厚度与第二基膜12的厚度之比可选为1.02、1.1、1.2、1.4、1.6、2.2、2.8、3.0、3.5、3.9、4.1、4.4、4.6、4.8、5等，或是上述任意两个数值组成的范围，例如，1.02-1.2、1.4-2.2、2.8-3.5、1.1-3.0、3.9-4.4、4.6-5等。
在本申请任意实施方式中，第一基膜11的厚度为2μm-14μm，可选为3μm-9μm；第二基膜12的厚度为2μm-12μm，可选为3μm-7μm。
第一基膜11的厚度可选为2μm、3.5μm、4μm、5μm、7μm、9μm、10μm、11μm、11.5μm、12μm、13.5μm、14μm等，或是上述任意两个数值组成的范围，例如，2μm-4μm、5μm-10μm、10μm-12μm、12μm-14μm等。在一些实施例中，第一基膜11的厚度可以为3μm-9μm。
第二基膜12的厚度可选为2μm、3μm、4μm、5μm、6μm、7μm、8μm、9μm、10μm、11μm、12μm等，或是上述任意两个数值组成的范围，例如，2μm-4μm、5μm-7μm、8μm-9μm、10μm-12μm等。在一些实施例中，第二基膜12的厚度可以为3μm-7μm。
当第一基膜的厚度和/或第二基膜的厚度满足上述条件时，使得隔离膜具有更佳的耐穿刺性能，从而可以提高二次电池的可靠性，同时，还可以提升电池的能量密度。
基膜的厚度可以采用本领域已知的设备和方法进行测试。例如，使用锂电池隔离膜测厚仪对基膜厚度定性测定。参考GB/T6672《塑料薄膜和薄片厚度的测定机械测量法》进行测试。具体的，可以采用如下步骤：取六组平行样品，利用万分尺测厚仪对每组样品不同位置的厚度进行测量，每组样品至少测20个点，取六组样品厚度的平均值即为基膜厚度。
第一基膜11和第二基膜12可以直接通过热压方式复合，在热压方式复合的过程中，如果温度过高，将导致孔隙率小、透气性差；如果温度过低，将导致第一基膜11和第二基膜12粘接不牢，因此，需要调节合适的热压温度。可选地，热压温度在20℃-50℃。
在本申请任意实施方式中，参阅图2，第一基膜11和第二基膜12之间还设置有中间层13，中间层13设置在第一基膜11和第二基膜12之间，中间层13包括粘结剂。可选地，中间层13还包括填充颗粒。可选地，填充颗粒包括无机颗粒、有机颗粒、有机-金属框架材料中的至少一种。当第一基膜和第二基膜之间设置有中间层时，不仅能补偿热压复合过程中的工艺缺陷，同时，能够进一步改善隔离膜的物理性质稳定，从而提高二次电池的可靠性。
在本申请任意实施方式中，粘结剂包括聚丙烯酸酯、聚丙烯酸、聚四氟乙烯、聚偏氟乙烯、偏氟乙烯-三氯乙烯共聚物、聚乙烯吡咯烷酮、聚乙酸乙烯酯、乙烯-乙酸乙烯酯共聚物、聚环氧乙烷、 聚芳酯、羧甲基纤维素、羟丙基纤维素、再生纤维素、乙酸纤维素、乙酸丙酸纤维素、乙酸丁酸纤维素、聚丙烯腈、聚乙烯醇、聚乙烯、聚丙烯、淀粉、氰基乙基支链淀粉中的一种或几种。当第一基膜和第二基膜之间设置有中间层，且中间层中的粘结剂包括以上组分时，能够提高二次电池的可靠性。
可选地，所述无机颗粒包括具有5以上介电常数的无机颗粒、具有离子传导性但不储存离子的无机颗粒和能够发生电化学反应的无机颗粒中的一种或多种。
可选地，所述具有5以上介电常数的无机颗粒可包括勃姆石、氧化铝、氧化锌、氧化硅、氧化钛、氧化锆、氧化钡、氧化钙、氧化镁、氧化镍、氧化锡、氧化铈、氧化钇、氧化铪、氢氧化铝、氢氧化镁、碳化硅、碳化硼、氮化铝、氮化硅、氮化硼、氟化镁、氟化钙、氟化钡、硫酸钡、硅酸镁铝、硅酸镁锂、硅酸镁钠、膨润土、水辉石、钛酸锆、钛酸钡、Pb(Zr,Ti)O3(简写为PZT)、Pb1-mLamZr1-nTinO3(简写为PLZT，0＜m＜1，0＜n＜1)、Pb(Mg3Nb2/3)O3-PbTiO3(简写为PMN-PT)、及其各自的改性无机颗粒中的至少一种。可选地，各无机颗粒的改性方式可为化学改性和/或物理改性。所述化学改性方式包括偶联剂改性(例如采用硅烷偶联剂、钛酸酯偶联剂等)、表面活性剂改性、聚合物接枝改性等。所述物理改性方式可为机械力分散、超声分散、高能处理等。通过改性处理能够减少无机颗粒的团聚，由此能使粘接层具有更稳定和更均一的结构；此外，通过选择具有特定官能团的偶联剂、表面活性剂或聚合物以改性无机颗粒，还有助于提升粘接层对电解液的浸润和保持特性、提升粘接层对第一基膜、第二基膜的粘结性。
可选地，所述具有离子传导性但不储存离子的无机颗粒可包括Li3PO4、磷酸钛锂Lix1Tiy1(PO4)3、磷酸钛铝锂Lix2Aly2Tiz1(PO4)3、(LiAlTiP)x3Oy3型玻璃、钛酸镧锂Lix4Lay4TiO3、硫代磷酸锗锂Lix5Gey5Pz2Sw、氮化锂Lix6Ny6、SiS2型玻璃Lix7Siy7Sz3和P2S5型玻璃Lix8Py8Sz4中的至少一种，0＜x1＜2，0＜y1＜3，0＜x2＜2，0＜y2＜1，0＜z1＜3，0＜x3＜4，0＜y3＜13，0＜x4＜2，0＜y4＜3，0＜x5＜4，0＜y5＜1，0＜z2＜1，0＜w＜5，0＜x6＜4，0＜y6＜2，0＜x7＜3，0＜y7＜2，0＜z3＜4，0＜x8＜3，0＜y8＜3，0＜z4＜7。由此能够进一步提升隔离膜的离子导通率。
可选地，所述能够发生电化学反应的无机颗粒可包括含锂过渡金属氧化物、含锂磷酸盐、碳基材料、硅基材料、锡基材料和锂钛化合物中的至少一种。
可选地，有机颗粒可以包括聚碳酸酯、聚噻吩、聚吡啶、聚苯乙烯、聚丙烯酸蜡、聚乙烯、聚丙烯、纤维素、纤维素改性剂(例如羧基甲基纤维素)、三聚氰胺树脂、酚醛树脂、聚酯(例如聚对苯二甲酸乙二醇酯、聚萘二甲酸乙二醇酯、聚对苯二甲酸丁二醇酯)、有机硅树脂、聚酰亚胺、聚酰胺酰亚胺、聚芳酰胺、聚苯硫醚、聚砜、聚醚砜、聚醚醚酮、聚芳醚酮、丙烯酸丁酯与甲基丙烯酸乙酯的共聚物(例如丙烯酸丁酯与甲基丙烯酸乙酯的交联聚合物)中的一种或多种。
可选地，有机-金属框架材料可以包括含氮杂环类配体构筑结构、有机羧酸类配体构筑结构、含氮氧混合类配体构筑结构中的一种或多种。
在一些实施例中，粘结剂的含量可以大于等于10％，可选为10％-30％，基于粘接层的总重量计。
在一些实施例中，填充物的含量可以小于等于90％，可选为40％-90％，60％-80％，基于粘接层的总重量计。
在一些实施例中，中间层还可以包括分散剂，例如羧甲基纤维素，由此可以调节中间层浆料的粘度，提升中间层的质量和均匀性。
在一些实施例中，分散剂的含量可以小于等于25％，可选为小于等于20％，基于粘接层的 总重量计。
在本申请任意实施方式中，隔离膜10满足下述(1)-(5)中的至少一项：
(1)隔离膜的穿刺强度为330gf-630gf，可选为400gf-600gf；
(2)隔离膜的横向拉伸强度≥700kg/cm2，可选为1000kg/cm2-1900kg/cm2；
(3)隔离膜的纵向拉伸强度≥1000kg/cm2，可选为1200kg/cm2-2200kg/cm2；
(4)隔离膜10在250℃、1h下的横向热收缩率为≤3％，可选为≤2.0％；
(5)隔离膜10在250℃、1h下的纵向热收缩率为≤3％，可选为≤2.0％。
当隔离膜上述(1)-(5)中至少一项满足所给的范围时，使得隔离膜具有良好的耐穿刺性能，从而可以提高二次电池的可靠性。
基膜或隔离膜的横向拉伸强度、纵向拉伸强度、横向热收缩率和纵向热收缩率均具有本领域公知的含义，可以采用本领域已知的设备和方法进行测试。例如，可参照标准GB/T36363-2018进行测试。
如果没有特别的说明，在隔离膜中所使用的各原料(例如第一基膜、第二基膜、粘结剂、填充物等)均可以通过市购获得。
[正极极片]
在二次电池中，正极极片通常包括正极集流体及设置在正极集流体上的正极膜层，正极膜层包括正极活性材料。
正极集流体可以采用常规金属箔片或复合集流体(可以将金属材料设置在高分子基材上形成复合集流体)。作为示例，正极集流体可以采用铝箔。
正极活性材料的具体种类不做限制，可以采用本领域已知的能够用于二次电池正极的活性材料，本领域技术人员可以根据实际需求进行选择。
作为示例，正极活性材料可以包括，但不限于，锂过渡金属氧化物，橄榄石结构的含锂磷酸盐及其各自的改性化合物中的一种或几种。锂过渡金属氧化物的示例可包括但不限于锂钴氧化物、锂镍氧化物、锂锰氧化物、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物、锂镍钴铝氧化物及其改性化合物中的一种或几种。橄榄石结构的含锂磷酸盐的示例可包括但不限于磷酸铁锂、磷酸铁锂与碳的复合材料、磷酸锰锂、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料及其改性化合物中的一种或几种。这些材料均可以通过商业途径获得。
上述各材料的改性化合物可以是对材料进行掺杂改性和/或表面包覆改性。
正极膜层通常更可选地包括粘结剂、导电剂和其他可选助剂。
作为示例，导电剂可以为超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、导电炭黑(Super P，SP)、石墨烯及碳纳米纤维中一种或几种。
作为示例，粘结剂可以为丁苯橡胶(Polymerized Styrene Butadiene Rubber，SBR)、水性丙烯酸树脂(water-basedacrylicresin)、聚偏二氟乙烯(Polyvinylidene Difluoride，PVDF)、聚四氟乙烯(Polytetrafluoroethylene，PTFE)、乙烯-醋酸乙烯酯共聚物(Ethylene-vinyl Acetate Copolymer，EVA)、聚丙烯酸(Polyacrylic Acid，PAA)、羧甲基纤维素(Carboxymethyl Cellulose，CMC)、聚乙烯醇(Polyvinyl Alcohol,Vinylalcohol Polymer，PVA)及聚乙烯醇缩丁醛(Polyvinyl Butyral，PVB)中的一种或几种。
[负极极片]
在二次电池中，负极极片通常包括负极集流体及设置在负极集流体上的负极膜层，负极膜层包括负极活性材料。
负极集流体可以采用常规金属箔片或复合集流体(例如可以将金属材料设置在高分子基材上形成复合集流体)。作为示例，负极集流体可以采用铜箔。
负极活性材料的具体种类不做限制，可以采用本领域已知的能够用于二次电池负极的活性材料，本领域技术人员可以根据实际需求进行选择。作为示例，负极活性材料可以包括，但不限于，人造石墨、天然石墨、硬碳、软碳、硅基材料和锡基材料中的一种或几种。硅基材料可选自单质硅、硅氧化合物(例如氧化亚硅)、硅碳复合物、硅氮复合物、硅合金中的一种或几种。锡基材料可选自单质锡、锡氧化合物、锡合金中的一种或几种。这些材料均可以通过商业途径获得。
在一些实施方式中，为了进一步提高电池的能量密度，负极活性材料可以包括硅基材料。
负极膜层通常更可选地包括粘结剂、导电剂和其他可选助剂。
作为示例，导电剂可以为超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中一种或几种。
作为示例，粘结剂可以为丁苯橡胶(SBR)、水性丙烯酸树脂(water-basedacrylicresin)、聚偏二氟乙烯(PVDF)、聚四氟乙烯(PTFE)、乙烯-醋酸乙烯酯共聚物(EVA)、聚乙烯醇(PVA)及聚乙烯醇缩丁醛(PVB)中的一种或几种。
作为示例，其他可选助剂可以是增稠及分散剂(例如羧甲基纤维素钠
Carboxymethylcellulose Sodium，CMC-Na)、PTC热敏电阻材料。
[电解液]
二次电池可以包括电解液，电解液在正极和负极之间起到传导离子的作用。电解液可以包括电解质盐和溶剂。
作为示例，电解质盐可选自六氟磷酸锂(LiPF6)、四氟硼酸锂(LiBF4)、高氯酸锂(LiClO4)、六氟砷酸锂(LiAsF6)、双氟磺酰亚胺锂(LiFSI)、双三氟甲磺酰亚胺锂(LiTFSI)、三氟甲磺酸锂(LiTFS)、二氟草酸硼酸锂(LiDFOB)、二草酸硼酸锂(LiBOB)、二氟磷酸锂(LiPO2F2)、二氟二草酸磷酸锂(LiDFOP)及四氟草酸磷酸锂(LiTFOP)中的一种或几种。
作为示例，溶剂可选自碳酸亚乙酯(Ethylene Carbonate，EC)、碳酸亚丙酯(Propylene Carbonate，PC)、碳酸甲乙酯(Methyl Ethyl Carbonate，EMC)、碳酸二乙酯(Diethyl Carbonate，DEC)、碳酸二甲酯(Dimethyl Darbonate，DMC)、碳酸二丙酯(Dipropyl Carbonate，DPC)、碳酸甲丙酯(Methyl Propyl Carbonate，MPC)、碳酸乙丙酯(Diisopropyl Carbonate，EPC)、碳酸亚丁酯(Butylene Carbonate，BC)、氟代碳酸亚乙酯(Fluoroethylene Carbonate，FEC)、甲酸甲酯(Methyl Formate，MF)、乙酸甲酯(Methyl Acetate，MA)、乙酸乙酯(Ethyl Acetate，EA)、乙酸丙酯(n-Propyl Acetate，PA)、丙酸甲酯(Methyl Propionate，MP)、丙酸乙酯(Ethyl Propanoate，EP)、丙酸丙酯(n-Propyl Propionate，PP)、丁酸甲酯(Methyl ButyrateMB)、丁酸乙酯(Ethyl Butyrate，EB)、1,4-丁内酯(1,4-Butyrolactone，GBL)、环丁砜(Tetramethylene Sulfone，SF)、二甲砜(Methyl Sulfone，MSM)、甲乙砜(Methyl Ethyl Sulfone，EMS)及二乙砜(Diethyl Sulfone，ESE)中的一种或几种。
在一些实施方式中，电解液中还包括添加剂。例如添加剂可以包括负极成膜添加剂，也可以包括正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温性能的添加剂、改善电池低温性能的添加剂。
在一些实施方式中，二次电池可以为锂离子二次电池。在本申请任意实施方式中，隔离膜10的第二基膜12朝向负极极片。
隔离膜10的第二基膜12朝向负极极片，第二基膜12的穿刺强度高，可以增加抗锂枝晶刺破的效果，提高二次电池的可靠性。
本申请实施例对二次电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。如图3是作为一个示例的方形结构的二次电池5。
在一些实施方式中，二次电池可包括外包装。该外包装用于封装正极极片、负极极片和电解质。
在一些实施方式中，二次电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳。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(Polypropylene，PP)、聚对苯二甲酸丁二醇酯(Polybutylene Terephthalate，PBT)、聚丁二酸丁二醇酯(Polybutylene Succinate，PBS)中的一种或几种。
在一些实施方式中，参照图4，外包装可包括壳体51和盖板53。其中，壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53能够盖设于开口，以封闭容纳腔。
本申请的二次电池的制备方法是公知的。在一些实施例中，可将正极极片、隔离膜10、负极极片和电解液组装形成二次电池。作为示例，可将正极极片、隔离膜10、负极极片经卷绕工艺和/或叠片工艺形成电极组件，将电极组件置于外包装中，烘干后注入电解液，经过真空封装、静置、化成、整形等工序，得到电池单体。多个电池单体还可以进一步经由串联或并联或混联组成电池模块。多个电池模块还可以经由串联或并联或混联形成电池包。在一些实施例中，多个电池单体还可以直接组成电池包。
图5是作为一个示例的电池模块4。参照图5，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。
电池模块4还可以包括具有容纳空间的外壳，多个二次电池5容纳于该容纳空间。
在一些实施方式中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以根据电池包的应用和容量进行调节。
图6和图7是作为一个示例的电池包1。参照图6和图7，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
[装置]
本申请还提供一种用电装置，用电装置包括本申请的二次电池。电池单体、电池模块或电池包可以作为装置的电源，也可以作为装置的能量存储单元。装置可以但不限于是移动设备(例如手机、笔记本电脑)、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)、电气列车、船舶及卫星、储能系统。
装置可以根据其使用需求来选择电池单体、电池模块或电池包。
图8是作为一个示例的用电装置。该用电装置可以为纯电动车、混合动力电动车、或插电式混合动力电动车。为了满足该用电装置对二次电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的用电装置可以是手机、平板电脑、笔记本电脑。该用电装置通常要求轻薄化，可以采用电池单体作为电源。
以下结合实施例进一步说明本申请的有益效果。
为了使本申请实施例所解决的技术问题、技术方案及有益效果更加清楚，以下将结合实施例和附图进行进一步详细说明。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。以下对至少一个示例性实施例的描述实际上仅仅是说明性的，决不作为对本申请及其应用的任 何限制。基于本申请中的实施例，本领域普通技术人员在没有付出创造性劳动前提下所获得的所有其他实施例都属于本申请保护的范围。
一、隔离膜的制备
隔离膜1：
(1)提供第一基膜和第二基膜：第一基膜为聚丙烯(PP)，第二基膜为聚乙烯(PE)，其中第一基膜的熔点为165℃，第二基膜的熔点为135℃。第一基膜的横向断裂伸长率为60％，纵向断裂伸长率为80％。第二基膜的横向断裂伸长率为130％，纵向断裂伸长率为75％。第一基膜的穿刺强度P1为120gf，第二基膜的穿刺强度P2为300gf；其中第一基膜的穿刺强度P1与第二基膜的穿刺强度P2之比P1/P2为0.40。
(2)配制中间层浆料：将粘结剂聚丙烯酸酯和填充物氧化铝颗粒、羧甲基纤维素按照1：4：1比例在适量溶剂去离子水中混合均匀，制成中间层浆料。
(3)将步骤(2)的中间层浆料涂布在步骤(1)的第二基膜的一侧，形成中间层。
(4)将第一基膜与步骤(3)的涂布后的第二基膜进行热压复合，得到隔离膜，其中，中间层在第一基膜和第二基膜之间。
隔离膜2-11的制备方法与隔离膜1相似，不同点在于：调整了第一基膜或第二基膜的熔点、物质、横向断裂伸长率、纵向断裂伸长率和穿刺强度中的一项或者多项，具体详见表1。其他的制备方法均与实施例1的隔离膜的制备方法一致。
二、电池的制备
实施例1
1、正极极片的制备
将正极活性材料LiNi0.8Co0.1Mn0.1O2(NCM811)、导电剂炭黑(SuperP)、粘结剂聚偏二氟乙烯(PVDF)按质量比96.2:2.7:1.1在适量的溶剂N-甲基吡咯烷酮(N-Methylpyrrolidone，NMP)中混合均匀，得到正极浆料，将正极浆料涂布于正极集流体铝箔上，通过烘干、冷压、分条、裁切工序，得到正极极片。
2、负极极片的制备
将负极活性材料人造石墨、导电剂炭黑(SuperP)、粘结剂丁苯橡胶(SBR)和羧甲基纤维素钠(CMC-Na)按质量比96.4:0.7:1.8:1.1在适量的溶剂去离子水中混合均匀，得到负极浆料，将负极浆料涂布于负极集流体铜箔上，通过烘干、冷压、分条、裁切工序，得到负极极片。
3、隔离膜
隔离膜采用上述制备的隔离膜1。
4、电解液的制备
将碳酸亚乙酯(EC)和碳酸甲乙酯(EMC)按质量比30:70进行混合，得到有机溶剂，将充分干燥的电解质盐LiPF6溶解于上述混合溶剂中，电解质盐的浓度为1.0mol/L，混合均匀后获得电解液。
5、二次电池的制备
将正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正极极片、负极极片之间起到隔离的作用，其中，第二基膜朝向负极极片，然后卷绕得到电极组件；将电极组件置于外包装中，将上述制备好的电解液注入到干燥后的二次电池中，经过真空封装、静置、化成、整形工序，获得二次电池。
实施例2-9和对比例1-2的二次电池与实施例1的二次电池的制备方法相似，不同点在于使用了 不同的隔离膜(其中，实施例1-9采用的是隔离膜1-9，对比例1-2采用的是隔离膜10-11)，具体详见表1。
三、电池性能测试
1、浅刺测试(60min)
在25℃及在100％SOC条件下对电池进行测试，将感温线按照正极柱/负极柱/大面中心(靠近针刺口上方5mm)/大面中心背面/电芯防爆阀顺序布置，电压线按照V正负/V正针/V负针顺序布置，且多路采集频率≤0.1S；使用φ1mm的耐高温钢针(针尖的圆锥角度为30°)，对准电芯大面中心位置，针刺速度0.01mm/s；针刺至正极到电压达到0.5V，继续刺入深度3mm，保持1h，观察仪器显示表显示数值，电压正常无波动为正常未失控，则记为PASS；若电压波动异常，电芯失效，则记为NP。
2、电池循环性能(圈)
25℃下，将实施例和对比例制备得到的二次电池以1C倍率恒流充电至充电截止电压V1，之后恒压充电至电流≤0.05C，静置5min，再以0.33C倍率恒流放电至放电截止电压V2，静置5min，此为一个充放电循环。按照此方法对电池进行循环充放电测试，直至电池容量衰减至80％。此时的循环圈数即为电池在25℃下的循环寿命。
由表1可见，对实施例1-9和对比例1-2进行比对分析，实施例1-9中，第二基膜的熔点低于第一基膜的熔点，且第二基膜的穿刺强度为220gf-460gf，隔离膜的穿刺强度为330gf-620gf，使用本申请的隔离膜的电池不仅能通过浅刺测试，且循环圈数增加，也即在同样的电池性能标准下，采用本申请所提供的隔离膜所制备的电池可靠性更高。
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 (15)

  1. 一种隔离膜，包括：
    第一基膜；
    第二基膜，所述第二基膜的熔点低于所述第一基膜的熔点；
    所述第二基膜的穿刺强度为220gf-460gf，所述隔离膜的穿刺强度为330gf-620gf。
  2. 如权利要求1所述的隔离膜，其中，所述第一基膜的穿刺强度与所述第二基膜的穿刺强度的比值为0.2-0.95，可选为0.3-0.75。
  3. 如权利要求1或2所述的隔离膜，其中，
    所述第一基膜的穿刺强度为100gf-220gf；和/或，
    所述第二基膜的穿刺强度为260gf-400gf。
  4. 如权利要求1-3任一项所述的隔离膜，其中，所述隔离膜满足下述(1)-(4)中的至少一个：
    (1)所述第一基膜的横向断裂伸长率为50％-200％，可选为60％-160％；
    (2)所述第一基膜的纵向断裂伸长率为40％-700％，可选为80％-600％；
    (3)所述第二基膜的横向断裂伸长率为40％-220％，可选为80％-170％；
    (4)所述第二基膜的纵向断裂伸长率为30％-100％，可选为40％-85％。
  5. 如权利要求1-4任一项所述的隔离膜，其中，
    所述第一基膜的平均纤维丝直径为60nm-300nm，可选为80nm-200nm；和/或，
    所述第二基膜的平均纤维丝直径为40nm-350nm，可选为70nm-180nm。
  6. 如权利要求1-5任一项所述的隔离膜，其中，所述第一基膜的熔点为155℃-360℃，可选为160℃-335℃；和/或，
    所述第二基膜的熔点为125℃-260℃，可选为130℃-220℃。
  7. 如权利要求1-6任一项所述的隔离膜，其中，
    所述第一基膜的材料的相对分子质量为40万-180万，可选为50万-130万；和/或，
    所述第二基膜的材料的相对分子质量为30万-150万，可选为40万-110万。
  8. 如权利要求1-7任一项所述的隔离膜，其中，所述第一基膜的厚度大于等于所述第二基膜的厚度；可选地，所述第一基膜的厚度与所述第二基膜的厚度之比为1.02-5，优选1.1-3.0。
  9. 如权利要求1-8任一项所述的隔离膜，其中，
    所述第一基膜的厚度为2μm-14μm，可选为3μm-9μm；和/或，
    所述第二基膜的厚度为2μm-12μm，可选为3μm-7μm。
  10. 如权利要求1-9任一项所述的隔离膜，其中，所述隔离膜还包括中间层，所述中间层设置在所述第一基膜和所述第二基膜之间，且所述中间层包括粘结剂；可选地，所述中间层包括粘结剂和填充颗粒。
  11. 如权利要求10所述的隔离膜，其中，所述粘结剂包括聚丙烯酸酯、聚丙烯酸、聚四氟乙烯、聚偏氟乙烯、偏氟乙烯-三氯乙烯共聚物、聚乙烯吡咯烷酮、聚乙酸乙烯酯、乙烯-乙酸乙烯酯共聚物、聚环氧乙烷、聚芳酯、羧甲基纤维素、羟丙基纤维素、再生纤维素、乙酸纤维素、乙酸丙酸纤维素、乙酸丁酸纤维素、聚丙烯腈、聚乙烯醇、聚乙烯、聚丙烯、淀粉、氰基乙基支链淀粉中的一种或几种；和/或，
    所述填充颗粒包括无机颗粒、有机颗粒、有机-金属框架材料中的至少一种。
  12. 如权利要求1-11任一项所述的隔离膜，其中，所述隔离膜满足下述(1)-(5)中的至少一项：
    (1)所述隔离膜的穿刺强度为330gf-630gf，可选为400gf-600gf；
    (2)所述隔离膜的横向拉伸强度≥700kg/cm2，可选为1000kg/cm2-1900kg/cm2；
    (3)所述隔离膜的纵向拉伸强度≥1000kg/cm2，可选为1200kg/cm2-2200kg/cm2；
    (4)所述隔离膜在250℃、1h下的横向热收缩率为≤3％，可选为≤2.0％；
    (5)所述隔离膜在250℃、1h下的纵向热收缩率为≤3％，可选为≤2.0％。
  13. 一种二次电池，包括如权利要求1-12任一项所述的隔离膜。
  14. 如权利要求13所述的隔离膜，其中，包括正极极片和负极极片，所述隔离膜设置在所述正极极片和所述负极极片之间，且所述第二基膜朝向所述负极极片。
  15. 一种用电装置，包括如权利要求13或14所述的二次电池。
PCT/CN2023/082339 2023-03-17 2023-03-17 隔离膜、二次电池和用电装置 Ceased WO2024192596A1 (zh)

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