WO2023040862A1 - 一种电极组件及其应用 - Google Patents

一种电极组件及其应用 Download PDF

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Publication number
WO2023040862A1
WO2023040862A1 PCT/CN2022/118591 CN2022118591W WO2023040862A1 WO 2023040862 A1 WO2023040862 A1 WO 2023040862A1 CN 2022118591 W CN2022118591 W CN 2022118591W WO 2023040862 A1 WO2023040862 A1 WO 2023040862A1
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Prior art keywords
diaphragm
positive electrode
separator
thickness
elongation rate
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PCT/CN2022/118591
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English (en)
French (fr)
Inventor
崔宏玉
贺飞
李素丽
李俊义
徐延铭
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Zhuhai Cosmx Battery Co Ltd
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Zhuhai Cosmx Battery Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—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
    • H01M50/46—Separators, membranes or diaphragms characterised by their combination with electrodes
    • 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
    • H01M50/491—Porosity
    • 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 lithium ion batteries, and in particular relates to an electrode assembly and its application.
  • Lithium-ion batteries are widely used in portable electronic devices, electric vehicles, aerospace and other fields due to their high volume specific energy, mass specific energy and cycle performance. With the continuous development of lithium-ion batteries, not only the demand for high energy density and high rate performance of lithium-ion batteries is increasing, but also the demand for safety performance of lithium-ion batteries is also increasing.
  • the existing lithium-ion battery is composed of a positive electrode, a negative electrode, and a polyolefin porous separator arranged between the positive electrode and the negative electrode.
  • mechanical abuse such as puncture
  • a short circuit will occur between the positive and negative electrodes. , leading to thermal runaway and safety issues.
  • the present application provides an electrode assembly, and a lithium ion battery including the electrode assembly has high safety performance.
  • the present application provides a lithium ion battery, which has high safety performance.
  • the present application provides an electrode assembly, including a positive electrode sheet, a negative electrode sheet, and a separator, and the separator is arranged between the positive electrode sheet and the negative electrode sheet;
  • the ratio of the elongation rate of the separator in the longitudinal direction to the thickness of the positive electrode sheet is (0.9-3.7): 1;
  • the ratio of the elongation rate of the separator in the width direction to the thickness of the positive electrode sheet is (0.9-3.7):1.
  • the thickness of the positive electrode sheet is 60-120 mm; and/or,
  • the elongation of the diaphragm in the length direction is 60-220%;
  • the elongation of the separator in the width direction is 60-220%.
  • the ratio of the extensibility of the separator in the width direction to the thickness of the positive electrode sheet is (1.2-3.7):1.
  • the elongation of the separator in the width direction is 100-220%.
  • the separator includes a polyolefin porous membrane substrate and a coating layer provided on at least one functional surface of the polyolefin porous membrane substrate.
  • the above electrode assembly wherein the porosity of the polyolefin porous separator substrate is 20-60%.
  • the coating layer includes at least one of inorganic particles and polymers.
  • the present application provides an electrochemical device, comprising the above-mentioned electrode assembly.
  • the electrode assembly of the present application starts with the diaphragm and the positive electrode sheet, and makes the ratio of the elongation of the diaphragm in the electrode assembly to the thickness of the positive electrode sheet more appropriate, thereby improving the safety performance of the lithium-ion battery. Specifically, when the electrode assembly is mechanically abused, the contact between the positive electrode current collector and the negative electrode active layer can be reduced, and the generation of short circuit points can be reduced, thereby reducing the probability of thermal runaway and making the lithium-ion battery have higher safety performance.
  • the lithium-ion battery of the present application has high safety performance because it includes the above-mentioned electrode assembly.
  • Fig. 1 is the top view of diaphragm in the present application
  • FIG. 2 is a schematic structural view of an electrode assembly in some embodiments of the present application.
  • Fig. 3 is a schematic diagram of a lithium-ion battery acupuncture test.
  • Figure 1 is a top view of the diaphragm in the application.
  • all definitions of "length” and “width” below refer to the "length L direction” and “width W direction” of the separator.
  • the length L direction of the diaphragm refers to the direction where the largest side length of the functional surface of the diaphragm is located
  • the width W direction of the diaphragm refers to the direction of the functional surface of the diaphragm. The direction in which the minimum edge length lies.
  • Fig. 2 is a schematic structural view of an electrode assembly in some embodiments of the present application.
  • the first aspect of the present application provides an electrode assembly, including a positive electrode sheet, a negative electrode sheet and a separator 3, and the separator 3 is arranged between the positive electrode sheet and the negative electrode sheet;
  • the ratio of the elongation rate of the diaphragm 3 in the length direction to the thickness of the positive electrode sheet is (0.9-3.7): 1;
  • the ratio of the elongation of the separator 3 in the width direction to the thickness of the positive electrode sheet is (0.9-3.7):1.
  • the electrode assembly of the present application can be formed by sequentially stacking the positive electrode sheet, the separator 3 and the negative electrode sheet; the winding arrangement of the positive electrode sheet, the separator 3 and the negative electrode sheet can also form the electrode assembly of the present application. .
  • the negative electrode sheet of the present application includes a negative electrode collector 4 and a negative electrode active layer 1 arranged on at least one functional surface of the negative electrode collector 4.
  • the present application does not specifically limit the negative electrode current collector 4 and the negative electrode active layer 1 , which may be selected from the negative electrode current collector 4 and the negative electrode active layer 1 commonly used in the field.
  • the elongation rate of the diaphragm 3 in the longitudinal direction refers to the ratio of the increase of the specified distance of the diaphragm 3 in the longitudinal direction to the specified distance when the diaphragm 3 breaks under a certain tensile force, expressed in percentage.
  • the elongation rate of the diaphragm 3 in the width direction refers to the ratio of the increase in the specified distance of the diaphragm 3 in the width direction to the width of the specified distance when the diaphragm 3 breaks under a certain tensile force, expressed as a percentage.
  • the designated distance of the diaphragm 3 in the length direction is: the distance between any two points A and B in the extension direction of the length of the diaphragm 3; the designated distance of the diaphragm 3 in the width direction is: the extension of the width of the diaphragm 3 The distance between any two points in the direction A' and B'.
  • the elongation rate of the diaphragm 3 in the length direction and the elongation rate of the diaphragm 3 in the width direction can be tested respectively by the following methods:
  • the diaphragm 3 is cut into a rectangular spline, and the extension direction of the long side of the spline is consistent with the length direction of the diaphragm 3, so that the edge of the spline is smooth without gaps (to prevent defects from affecting the test results).
  • the elongation test method of the diaphragm 3 in the width direction is basically the same as the elongation test method in the length direction, the only difference is that the extension direction of the long side of the spline is consistent with the width direction of the diaphragm 3 .
  • the positive electrode sheet of the present application includes a positive electrode collector 2 and a positive electrode active layer 5 disposed on at least one functional surface of the positive electrode collector 2 .
  • the thickness of the positive electrode sheet refers to the sum of the thickness of the positive electrode active layer 5 and the thickness of the positive electrode current collector 2 .
  • the ratio of the elongation rate of the separator 3 in the longitudinal direction to the thickness of the positive electrode sheet is (0.9-3.7):1, and the unit is %/mm.
  • the ratio of the elongation rate of the separator 3 in the width direction to the thickness of the positive electrode sheet is (0.9-3.7):1, and the unit is %/mm.
  • the ratio of the elongation rate of the separator 3 in the longitudinal direction to the thickness of the positive electrode sheet and the ratio of the elongation rate of the separator 3 in the width direction to the thickness of the positive electrode sheet can be the same or different, as long as they are within the above range within.
  • the electrode assembly of the present application can be obtained by stacking or winding the positive electrode sheet, separator 3 and negative electrode sheet according to the conventional assembly method, wherein the elongation of the separator 3 in length and width is the same as that of the positive electrode sheet
  • the thickness ratio satisfies the above requirements.
  • the electrode assembly can be prepared by selecting a separator 3 with a suitable elongation rate that matches the above-mentioned ratio according to the thickness of the positive electrode sheet on the basis of the positive electrode sheet; A positive electrode sheet with a suitable thickness is used to prepare an electrode assembly.
  • the present application does not limit the preparation methods of the positive electrode sheet and the negative electrode sheet.
  • the positive electrode active material, the conductive agent, and the binder are added to the stirring tank according to a certain mass ratio, a certain proportion of NMP solution is added, and the positive electrode active slurry with a certain solid content is obtained by stirring, and the positive electrode active slurry is The material is coated on at least one functional surface of the positive electrode current collector 2, and then dried to remove the solvent in the positive electrode active slurry, and finally the rolling, cutting, and sheet-making processes are sequentially performed to obtain the positive electrode sheet.
  • the negative electrode active material, conductive agent, and binder are added into the stirring tank according to a certain mass ratio, a certain proportion of deionized water is added, and the negative electrode active slurry with a certain solid content is obtained by stirring.
  • the slurry is coated on at least one functional surface of the negative electrode current collector 4, and then dried to remove the moisture in the negative electrode active slurry, and finally the rolling, cutting, and sheet-making processes are sequentially performed to obtain the negative electrode sheet.
  • the electrode assembly of the present application takes the diaphragm 3 and the positive electrode sheet as objects, by making the elongation of the diaphragm 3 in the electrode assembly more match the thickness of the positive electrode sheet, that is, making the elongation of the diaphragm 3 in the longitudinal direction consistent with the thickness of the positive electrode sheet
  • the thickness ratio is (0.9-3.7):1; the ratio of the elongation rate of the diaphragm in the width direction to the thickness of the positive electrode sheet is (0.9-3.7):1, so as to improve the safety performance of the lithium-ion battery.
  • the contact between the positive electrode current collector 2 and the negative electrode active layer 1 can be reduced, the generation of short circuit points can be reduced, and the probability of thermal runaway can be reduced , can make the lithium ion battery containing the electrode assembly of the present application have higher safety performance.
  • the thickness of the positive electrode sheet is 60-120mm; and/or,
  • the elongation of the diaphragm 3 in the length direction is 60-220%;
  • the elongation of the separator 3 in the width direction is 60-220%.
  • the elongation rate of the membrane 3 in the length direction is 100-220%; the elongation rate of the membrane 3 in the width direction is 100-220%.
  • the separator 3 in order to better improve the safety performance of the lithium-ion battery, includes a polyolefin porous separator substrate and a coating layer disposed on at least one functional surface of the polyolefin porous separator substrate.
  • the diaphragm 3 of the present application can be obtained by providing a coating layer on any functional surface of the polyolefin porous diaphragm substrate, or by providing a coating layer on both functional surfaces of the polyolefin porous diaphragm substrate. get.
  • the elongation rate of the diaphragm 3 is mainly related to the elongation rate of the polyolefin porous diaphragm substrate.
  • the polyolefin porous membrane substrate has a thickness of 1-20 ⁇ m.
  • the thickness of the polyolefin porous diaphragm substrate is too thick, the excessively thick polyolefin porous diaphragm substrate will make the electrode assembly too thick, which is not conducive to the optimization of the energy density of lithium-ion batteries. If the polyolefin porous diaphragm substrate The thickness is too thin, and the polyolefin porous separator base material that is too thin is prone to damage during the long-term operation of the lithium-ion battery, which shortens the service life of the lithium-ion battery. In the present application, the thickness of the polyolefin porous separator substrate is 1-20 ⁇ m, and within this range, the lithium-ion battery can have good energy density and long service life.
  • the porosity of the polyolefin porous separator substrate is 20-60%.
  • the polyolefin porous separator substrate meeting the above porosity can not only meet the electrical properties of the lithium-ion battery, but also help to improve the mechanical properties of the polyolefin porous separator substrate and prolong the service life of the lithium-ion battery.
  • the air permeability of the polyolefin porous membrane substrate is 30-250 sec/100 cc.
  • the air permeability value of the polyolefin porous membrane substrate refers to the time required for 100 cc of air to pass through the polyolefin porous membrane substrate under a pressure of 0.25 MPa.
  • the air permeability value of the polyolefin porous diaphragm substrate is too small, the polyolefin porous diaphragm substrate is easy to permeate other substances, and the self-discharge of the lithium-ion battery is large.
  • the air permeability value of the polyolefin porous diaphragm substrate is too large, it is easy to make The internal resistance of the lithium-ion battery is too large, which affects the electrical performance of the lithium-ion battery.
  • the air permeability of the polyolefin porous separator substrate is 30-250 sec/100 cc, the lithium-ion battery can have both good electrical performance and low self-discharge performance.
  • the thickness of the coating layer is 0.5-12 ⁇ m.
  • the coating layer includes at least one of inorganic particles and polymers.
  • the inorganic particles of the present application can be selected from inorganic particles commonly used in the art, for example, can be selected from alumina, silicon dioxide, boehmite, zinc oxide, magnesium oxide, zirconium dioxide, titanium oxide, barium oxide, calcium oxide, At least one of aluminum nitride, titanium nitride, silicon nitride, boron nitride, aluminum hydroxide, magnesium hydroxide and barium sulfate.
  • the polymer of the present application can be selected from commonly used polymers in this field, for example, can be selected from polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, sodium carboxymethyl cellulose, polyacrylate, polyacrylonitrile , polyvinyl alcohol, styrene-butadiene rubber, polyurethane, ethylene-acrylic acid copolymer, polymethyl methacrylate, polyimide, aramid, polystyrene and polyester.
  • the coating layer only includes inorganic particles, it is called an inorganic coating layer; if the polymer only includes polymers, it is called an organic coating layer; if the coating layer includes both organic particles and polymers, it is called a composite coating layer. coating layer.
  • the diaphragm of the present application can be obtained by setting at least one of an inorganic coating layer, an organic coating layer and a composite coating layer on any functional surface of a polyolefin porous diaphragm substrate, or by The two functional surfaces of the material are provided with at least one of an inorganic coating layer, an organic coating layer and a composite coating layer.
  • the inorganic coating layer, the organic coating layer and the composite coating layer are arranged on a certain functional surface of the polyolefin porous diaphragm substrate, the inorganic coating layer, the organic coating layer and the composite coating layer At least two of them can be stacked, and at least two of the inorganic coating layer, the organic coating layer and the composite coating layer can also be arranged side by side on the functional surface of the polyolefin porous membrane substrate.
  • the present application does not specifically limit the order of stacked arrangements, nor does it specifically limit the order of parallel arrangements.
  • the inorganic coating layer is arranged on a certain functional surface of the polyolefin porous membrane substrate, and the organic coating layer and/or composite coating layer is arranged on the functional surface of the inorganic coating layer away from the polyolefin porous membrane substrate. surface.
  • a second aspect of the present application provides a lithium ion battery, comprising the above-mentioned electrode assembly.
  • the lithium-ion battery of the present application has more excellent safety performance because it includes the above-mentioned electrode assembly.
  • One functional surface of the polyolefin porous diaphragm substrate adopts gravure coating to set the alumina ceramic layer, and then adopts gravure coating to set the polyvinylidene fluoride (PVDF) glue layer on the other functional surface of the polyolefin porous diaphragm substrate, in The functional surface of the alumina ceramic layer away from the polyolefin porous diaphragm substrate is coated with a PVDF adhesive layer by gravure coating to obtain a diaphragm;
  • PVDF polyvinylidene fluoride
  • the thickness of the polyolefin porous diaphragm substrate is 5 ⁇ m
  • the porosity of the polyolefin porous diaphragm substrate is 32%
  • the air permeability value of the polyolefin porous diaphragm substrate is 145sec/100cc
  • the thickness of the alumina ceramic layer is 2 ⁇ m
  • PVDF The thickness of the adhesive layer is 1 ⁇ m
  • the elongation rate of the separator in the longitudinal direction is 180%
  • the elongation rate of the separator in the width direction is 165%.
  • the positive electrode active material lithium cobaltate, the conductive agent conductive carbon black, and the binder PVDF into the stirring tank according to the mass ratio of 97.2:1.5:1.3, then add the NMP solution, and fully stir to obtain the positive electrode active slurry.
  • the slurry is respectively coated on the two functional surfaces of the aluminum foil of the positive electrode current collector, then dried to remove the solvent, and finally the positive electrode sheet is obtained by rolling, cutting and sheeting in sequence;
  • the thickness of the positive electrode sheet is 90mm.
  • the separator obtained in step 1, the positive electrode sheet obtained in step 2, and the negative electrode sheet obtained in step 3 are stacked in the order of positive electrode sheet, separator and negative electrode sheet, and then wound to obtain an electrode assembly;
  • the ratio of the elongation rate of the separator in the longitudinal direction to the thickness of the positive electrode sheet is 2:1, and the ratio of the elongation rate of the separator in the width direction to the thickness of the positive electrode sheet is 1.83:1.
  • step 4 Place the electrode assembly obtained in step 4 in the aluminum-plastic film of the outer packaging. After the aluminum-plastic film is top-sealed and side-sealed, the moisture is removed by baking, and the electrolyte is injected into the outer packaging. Formation and shaping to obtain lithium-ion batteries;
  • the electrolyte solution is prepared by the following steps: in a glove box filled with argon (H 2 O ⁇ 0.1ppm, O 2 ⁇ 0.1ppm), ethylene carbonate (EC), propylene carbonate (PC), dicarbonate Mix ethyl ester (DEC) and n-propyl propionate evenly, then add 1.2mol/L fully dry lithium hexafluorophosphate (LiPF 6 ) to it, dissolve in non-aqueous organic solvent, stir evenly, and pass the test of moisture and free acid After that, the basic electrolyte is obtained.
  • argon H 2 O ⁇ 0.1ppm, O 2 ⁇ 0.1ppm
  • EC ethylene carbonate
  • PC propylene carbonate
  • DEC dicarbonate Mix ethyl ester
  • LiPF 6 lithium hexafluorophosphate
  • step 1 of this embodiment the elongation rate of the diaphragm in the length direction and the elongation rate of the diaphragm in the width direction are obtained by a method test comprising the following steps:
  • test method for the elongation of the diaphragm in the width direction is basically the same as the test method for the elongation in the length direction, the only difference is that the extension direction of the long side of the spline is consistent with the width direction of the diaphragm 3 .
  • step 1 the two functional surfaces of the polyolefin porous diaphragm substrate are provided with an alumina ceramic layer by gravure coating, and the PVDF adhesive layer is respectively arranged on the functional surface of the alumina ceramic layer far away from the polyolefin porous diaphragm substrate by gravure coating , to obtain the diaphragm.
  • the elongation rate of the separator in the longitudinal direction, the elongation rate of the separator in the width direction, and the thickness of the positive electrode sheet are the same as those in Embodiment 1.
  • step 1 of this embodiment the test methods for the elongation rate of the membrane in the length direction and the elongation rate of the membrane in the width direction are the same as those in Example 1.
  • step 1 aluminum oxide and PVDF are mixed to obtain a mixed slurry, and the mixed slurry is respectively arranged on the two functional surfaces of the polyolefin porous diaphragm substrate by gravure coating to obtain a coating layer and a diaphragm;
  • the thickness of the coating layer is 4 ⁇ m, and the mass ratio of alumina to PVDF is 9:1.
  • the elongation rate of the separator in the longitudinal direction, the elongation rate of the separator in the width direction, and the thickness of the positive electrode sheet are the same as those in Embodiment 1.
  • step 1 of this embodiment the test methods for the elongation rate of the membrane in the length direction and the elongation rate of the membrane in the width direction are the same as those in Example 1.
  • step 1 a polyolefin porous diaphragm base material different from that in Example 1 is used, so that the elongation rate of the diaphragm in the length direction is 105%, and the elongation rate of the diaphragm in the width direction is 95%;
  • step 2 the thickness of the positive electrode sheet is 75 mm.
  • the ratio of the elongation rate of the separator in the longitudinal direction to the thickness of the positive electrode sheet is 1.4:1
  • the ratio of the elongation rate of the separator in the width direction to the thickness of the positive electrode sheet is 1.27:1.
  • step 1 of this embodiment the test methods for the elongation rate of the membrane in the length direction and the elongation rate of the membrane in the width direction are the same as those in Example 1.
  • step 1 a polyolefin porous membrane substrate different from that in Example 2 was used, wherein the thickness of the polyolefin porous membrane substrate was 7 ⁇ m, and the elongation of the membrane in the width direction was 175%.
  • the ratio of the elongation rate of the separator in the width direction to the thickness of the positive electrode sheet is 1.94:1.
  • the elongation rate of the separator in the longitudinal direction and the thickness of the positive electrode sheet are the same as those in Embodiment 2.
  • step 1 of this embodiment the test methods for the elongation rate of the diaphragm in the length direction and the elongation rate of the diaphragm in the width direction are the same as those in embodiment 2.
  • step 1 the porosity and gas permeability value of the polyolefin porous diaphragm substrate different from that in Example 1 are used, wherein the porosity of the polyolefin porous diaphragm substrate is 39%, and the gas permeability value of the polyolefin porous diaphragm substrate is 105sec/100cc.
  • the elongation rate of the separator in the longitudinal direction and the thickness of the positive electrode sheet are the same as those in Embodiment 1.
  • step 1 of this embodiment the test methods for the elongation rate of the diaphragm in the length direction and the elongation rate of the diaphragm in the width direction are the same as those in embodiment 2.
  • step 1 the polyolefin porous diaphragm base material whose elongation rate is different from that in Example 1 is used, so that the elongation rate of the diaphragm in the length direction is 180%, and the elongation rate of the diaphragm in the width direction is 180%;
  • step 2 the thickness of the positive electrode sheet is 60 mm.
  • the ratio of the elongation rate of the separator in the longitudinal direction to the thickness of the positive electrode sheet is 3:1, and the ratio of the elongation rate of the separator in the width direction to the thickness of the positive electrode sheet is 3:1.
  • step 1 of this embodiment the test methods for the elongation rate of the membrane in the length direction and the elongation rate of the membrane in the width direction are the same as those in Example 1.
  • step 1 the polyolefin porous diaphragm base material whose elongation rate is different from that in Example 1 is used, so that the elongation rate of the diaphragm in the length direction is 110%, and the elongation rate of the diaphragm in the width direction is 110%;
  • the ratio of the elongation rate of the separator in the longitudinal direction to the thickness of the positive electrode sheet is 1.2:1
  • the ratio of the elongation rate of the separator in the width direction to the thickness of the positive electrode sheet is 1.2:1.
  • step 1 of this embodiment the test methods for the elongation rate of the membrane in the length direction and the elongation rate of the membrane in the width direction are the same as those in Example 1.
  • step 1 the polyolefin porous diaphragm base material whose elongation rate is different from that in Example 1 is used, so that the elongation rate of the diaphragm in the length direction is 81%, and the elongation rate of the diaphragm in the width direction is 81%;
  • the ratio of the elongation rate of the separator in the longitudinal direction to the thickness of the positive electrode sheet is 0.9:1
  • the ratio of the elongation rate of the separator in the width direction to the thickness of the positive electrode sheet is 0.9:1.
  • step 1 of this embodiment the test methods for the elongation rate of the membrane in the length direction and the elongation rate of the membrane in the width direction are the same as those in Example 1.
  • step 1 the polyolefin porous diaphragm base material whose elongation rate is different from that in Example 1 is used, so that the elongation rate of the diaphragm in the length direction is 220%, and the elongation rate of the diaphragm in the width direction is 220%;
  • the ratio of the elongation rate of the separator in the longitudinal direction to the thickness of the positive electrode sheet is 3.7:1
  • the ratio of the elongation rate of the separator in the width direction to the thickness of the positive electrode sheet is 3.67:1.
  • step 1 of this embodiment the test methods for the elongation rate of the membrane in the length direction and the elongation rate of the membrane in the width direction are the same as those in Example 1.
  • the thickness of the positive electrode sheet is 120mm;
  • the ratio of the elongation rate of the separator in the longitudinal direction to the thickness of the positive electrode sheet is 1.5:1, and the ratio of the elongation rate of the separator in the width direction to the thickness of the positive electrode sheet is 1.375:1.
  • step 1 of this embodiment the test methods for the elongation rate of the membrane in the length direction and the elongation rate of the membrane in the width direction are the same as those in Example 1.
  • step 1 the polyolefin porous diaphragm base material whose elongation rate is different from that in Example 7 is used, so that the elongation rate of the diaphragm in the length direction is 60%, and the elongation rate of the diaphragm in the width direction is 60%;
  • the ratio of the elongation rate of the separator in the longitudinal direction to the thickness of the positive electrode sheet is 1:1, and the ratio of the elongation rate of the separator in the width direction to the thickness of the positive electrode sheet is 1:1.
  • step 1 of this embodiment the test methods for the elongation rate of the diaphragm in the length direction and the elongation rate of the diaphragm in the width direction are the same as those in embodiment 7.
  • step 1 the polyolefin porous diaphragm base material whose elongation rate is different from that in Example 1 is used, so that the elongation rate of the diaphragm in the length direction is 220%, and the elongation rate of the diaphragm in the width direction is 220%;
  • the ratio of the elongation rate of the separator in the longitudinal direction to the thickness of the positive electrode sheet is 2.44:1
  • the ratio of the elongation rate of the separator in the width direction to the thickness of the positive electrode sheet is 2.44:1.
  • step 1 of this embodiment the test methods for the elongation rate of the membrane in the length direction and the elongation rate of the membrane in the width direction are the same as those in Example 1.
  • step 1 the polyolefin porous diaphragm base material whose elongation rate is different from that in Example 1 is used, so that the elongation rate of the diaphragm in the length direction is 100%, and the elongation rate of the diaphragm in the width direction is 100%;
  • the thickness of the positive electrode sheet is 80mm;
  • the ratio of the elongation rate of the separator in the longitudinal direction to the thickness of the positive electrode sheet is 1.25:1
  • the ratio of the elongation rate of the separator in the width direction to the thickness of the positive electrode sheet is 1.25:1.
  • step 1 of this embodiment the test methods for the elongation rate of the membrane in the length direction and the elongation rate of the membrane in the width direction are the same as those in Example 1.
  • step 1 a polyolefin porous diaphragm base material different from that of Example 1 is used, so that the elongation of the diaphragm in the length direction is 58%, and the elongation of the diaphragm in the width direction is 62%;
  • the ratio of the elongation rate of the separator in the longitudinal direction to the thickness of the positive electrode sheet is 0.64:1
  • the ratio of the elongation rate of the separator in the width direction to the thickness of the positive electrode sheet is 0.69:1.
  • the thickness of the positive electrode sheet is the same as that of Example 1.
  • step 1 of this comparative example the test methods for the elongation rate of the diaphragm in the length direction and the elongation rate of the diaphragm in the width direction are the same as those in Example 1.
  • step 1 a polyolefin porous diaphragm base material different from that of Example 1 is used, so that the elongation rate of the diaphragm in the length direction is 92%, and the elongation rate of the diaphragm in the width direction is 89%;
  • the thickness of the positive electrode sheet in step 2 is 120mm.
  • the ratio of the elongation rate of the separator in the longitudinal direction to the thickness of the positive electrode sheet is 0.77:1
  • the ratio of the elongation rate of the separator in the width direction to the thickness of the positive electrode sheet is 0.74:1.
  • step 1 of this comparative example the test methods for the elongation rate of the diaphragm in the length direction and the elongation rate of the diaphragm in the width direction are the same as those in Example 1.
  • the lithium-ion batteries in the examples and comparative examples are charged according to the standard charge-discharge mode. After fully charged, the lithium-ion batteries are subjected to acupuncture testing. Use a steel needle with a diameter of 3mm to place the lithium-ion battery on a horizontal plane. The speed of /s passes through the center of the lithium-ion battery and remains in the lithium-ion battery for 10 minutes. If the lithium-ion battery does not catch fire or explode, it is considered to pass the test. 100 lithium-ion batteries of each example and comparative example were tested, and the pass rate of acupuncture was calculated. The test results are shown in Table 1.
  • Fig. 3 is a schematic diagram of a lithium-ion battery acupuncture test.
  • steel needles pass through negative electrode active layer 1, negative electrode current collector 4, negative electrode active layer 1, separator 3, positive electrode active layer 5, and positive electrode current collector 2 in sequence.
  • the internal current temperature of the ion battery will rise, which will cause the lithium ion battery to catch fire, indicating that the acupuncture test result of the lithium ion battery is not passed.
  • Example 1 95/100
  • Example 2 99/100
  • Example 3 91/100
  • Example 4 87/100
  • Example 5 100/100
  • Example 6 94/100
  • Example 7 100/100
  • Example 8 83/100
  • Example 9 69/100
  • Example 10 100/100
  • Example 11 89/100
  • Example 12 75/100
  • Example 13 100/100
  • Example 14 85/100
  • the electrode assembly of the present application is used in lithium ion batteries, which can improve the safety performance of lithium ion batteries. It is proved that by matching the elongation rate of the separator in the electrode assembly and the thickness of the positive sheet, the generation of short circuit points between the positive and negative electrodes can be reduced during the acupuncture test, and the heat generated by the short circuit can be effectively reduced, thereby improving the safety performance of the battery.

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Abstract

本申请提供一种电极组件及其应用。本申请的电极组件，包括正极片、负极片和隔膜，所述隔膜设置于所述正极片和所述负极片之间；所述隔膜在长度方向上的延展率与所述正极片的厚度之比为(0.9-3.7)：1；所述隔膜在宽度方向上的延展率与所述正极片的厚度之比为(0.9-3.7)：1。本申请的电极组件，通过匹配电极组件中隔膜的延展率与正极片的厚度，当电极组件受到机械滥用时，可以减少正极集流体与负极活性层的接触，减少短路点的产生，从而减少热失控发生的概率，可以使锂离子电池具有较高的安全性能。

Description

一种电极组件及其应用
本申请要求于2021年09月15日提交中国专利局、申请号为202111081831.2、申请名称为“一种电极组件及其应用”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请属于锂离子电池技术领域，具体涉及一种电极组件及其应用。
背景技术
锂离子电池由于具有较高体积比能量、质量比能量和循环性能，因而广泛应用于便携式电子设备、电动汽车以及航空航天等领域。随着锂离子电池的不断发展，人们不仅对锂离子电池高能量密度和高倍率等性能的需求不断增加，而且对锂离子电池安全性能的需求也不断增加。
现有的锂离子电池，通过正极、负极以及设置在正极和负极之间的聚烯烃多孔隔膜组成，现有的锂离子电池经机械滥用(如穿刺)测试时，正负极之间会产生短路，导致热失控发生，引发安全问题。
申请内容
本申请提供一种电极组件，包括该电极组件的锂离子电池具有较高的安全性能。
本申请提供一种锂离子电池，该锂离子电池具有较高的安全性能。
本申请提供一种电极组件，包括正极片、负极片和隔膜，所述隔膜设置于所述正极片和所述负极片之间；
所述隔膜在长度方向上的延展率与所述正极片的厚度之比为(0.9-3.7)：1；
所述隔膜在宽度方向上的延展率与所述正极片的厚度之比为(0.9-3.7)：1。
如上所述的电极组件，其中，所述正极片的厚度为60-120mm；和/或，
所述隔膜在长度方向上的延展率为60-220％；
所述隔膜在宽度方向上的延展率为60-220％。
如上所述的电极组件，其中，所述隔膜在长度方向上的延展率与所述正极片的厚度之比为(1.2-3.7)：1；
所述隔膜在宽度方向上的延展率与所述正极片的厚度之比为(1.2-3.7)：1。
如上所述的电极组件，其中，所述隔膜在长度方向上的延展率为100-220％；
所述隔膜在宽度方向上的延展率为100-220％。
如上所述的电极组件，其中，所述隔膜包括聚烯烃多孔隔膜基材以及设置在所述聚烯烃多孔隔膜基材的至少一个功能表面的涂覆层。
如上所述的电极组件，其中，所述聚烯烃多孔隔膜基材的厚度为1-20μm。
如上所述的电极组件，其中，所述聚烯烃多孔隔膜基材的孔隙率为20-60％。
如上所述的电极组件，其中，所述聚烯烃多孔隔膜基材的透气值为30-250sec/100cc。
如上所述的电极组件，其中，所述涂覆层的厚度为0.5-12μm。
如上所述的电极组件，其中，所述涂覆层包括无机颗粒与聚合物中的至少一种。
本申请提供一种电化学装置，包含如上所述的电极组件。
本申请的电极组件，以隔膜和正极片为着手点，使电极组件中隔膜延展率与正极片厚度之比更为适宜，从而实现锂离子电池安全性能的改善。具体地，当电极组件受到机械滥用时，可以减少正极集流体与负极活性层的接触，减少短路点的产生，从而减少热失控发生的概率，使锂离子电池具有较高的安全性能。
本申请的锂离子电池，由于包括上述的电极组件，所以具有较高的安全性能。
附图说明
图1为本申请中隔膜的俯视图；
图2为本申请一些实施方式中电极组件的结构示意图；
图3为锂离子电池针刺测试的示意图。
附图标记说明：
1：负极活性层；
2：正极集流体；
3：隔膜：
4：负极集流体；
5：正极活性层。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其它实施例，都属于本申请保护的范围。
图1为申请中隔膜的俯视图。如图1所示，以下，所有的关于“长度”和“宽度”的定义，均是以隔膜的“长度L方向”和“宽度W方向”为参照。以功能表面(功能表面是指两个最大的且相对的表面)为长方形为例，则隔膜的长度L方向是指隔膜功能表面最大边长所在的方向，隔膜的宽度W方向是指隔膜功能表面最小边长所在的方向。
图2为本申请一些实施方式中电极组件的结构示意图。如图2所示，本申请的第一方面提供一种电极组件，包括正极片、负极片和隔膜3，隔膜3设置于正极片和负极片之间；
隔膜3在长度方向上的延展率与正极片的厚度之比为(0.9-3.7)：1；
隔膜3在宽度方向上的延展率与正极片的厚度之比为(0.9-3.7)：1。
可以理解的是，本申请中，将正极片、隔膜3和负极片依次层叠设置可以形成本申请的电极组件；将正极片、隔膜3和负极片进行卷绕设置也可以形成本申请的电极组件。
本申请的负极片包括负极集流体4和设置在负极集流体4至少一个功能 表面的负极活性层1。
本申请对负极集流体4、负极活性层1不做特别限定，可以选自本领域常用的负极集流体4、负极活性层1。
本申请中，隔膜3在长度方向上的延展率是指在一定拉力作用下，隔膜3发生断裂时，隔膜3在长度方向指定距离的增加量与指定距离的比值，以百分率记。隔膜3在宽度方向上的延展率是指在一定拉力作用下，隔膜3发生断裂时，隔膜3在宽度方向上指定距离的增加量与指定距离的宽度的比值，以百分率记。
本申请中，隔膜3在长度方向的指定距离为：隔膜3长度的延伸方向上任意两点A点和B点之间的距离；隔膜3在宽度方向上的指定距离为：隔膜3宽度的延伸方向上任意两点A’点和B’点之间的距离。
本申请中，可以通过以下方法分别测试隔膜3在长度方向上的延展率以及隔膜3在宽度方向上的延展率：
将隔膜3裁切成长方形样条，样条长边的延伸方向与隔膜3的长度方向一致，使样条边缘平滑无缺口(防止缺陷影响测试结果)。将上述样条夹在万能拉力机上下夹具中间，样条的长轴(样条长度方向上的中轴线)与夹具的中心线重合，在100mm/min的拉伸试验速度下，沿样条的长度方向对样条进行拉伸，直至隔膜3破裂，获得隔膜3在长度方向上的指定距离的增加量，计算隔膜3在长度方向的延展率。
隔膜3在宽度方向的延展率测试方法与在长度方向上的延展率的测试方法基本相同，唯一不同的是，样条长边的延伸方向与隔膜3的宽度方向一致。
本申请的正极片包括正极集流体2以及设置在正极集流体2至少一个功能表面的正极活性层5。本申请中，正极片的厚度指的是正极活性层5的厚度与正极集流体2的厚度之和。
本申请中隔膜3在长度方向上的延展率与正极片的厚度之比为(0.9-3.7)：1，其单位为％/mm。本申请中隔膜3在宽度方向上的延展率与正极片的厚度之比为(0.9-3.7)：1，其单位为％/mm。
本申请中，隔膜3在长度方向上的延展率与正极片的厚度之比与隔膜3在宽度按方向上的延展率与正极片的厚度之比可以相同，也可以不相同，只要在上述范围之内即可。
本申请的电极组件通过将正极片、隔膜3以及负极片按照常规的组装方式进行叠片式组装或卷绕式组装即可得到，其中，隔膜3在长度和宽度上的延展率与正极片的厚度之比满足上述要求。例如，可以以正极片为基准，根据正极片的厚度选择匹配上述比值的具有适宜延展率的隔膜3，制备电极组件；也可以以隔膜3为基准，根据隔膜3的延展率选择匹配上述比值的具有适宜厚度的正极片，制备电极组件。
本申请不限定正极片和负极片的制备方法。在一种实施方式中，将正极活性材料、导电剂、粘接剂按照一定质量比例加入到搅拌罐中，加入一定比例的NMP溶液，搅拌得到一定固含量的正极活性浆料，将正极活性浆料涂布在正极集流体2的至少一个功能表面，然后进行烘干除去正极活性浆料中的溶剂，最后依次进行辊压、分切、制片工序，得到正极片。
在一种实施方式中，将负极活性材料、导电剂、粘接剂按照一定质量比例加入到搅拌罐中，加入一定比例的去离子水，搅拌得到一定固含量的负极活性浆料，将负极活性浆料涂布在负极集流体4的至少一个功能表面，然后进行烘干除去负极活性浆料中的水分，最后依次进行辊压、分切、制片工序，得到负极片。
本申请的电极组件，以隔膜3和正极片为对象，通过使电极组件中隔膜3的延展率与正极片的厚度更为匹配，即，使隔膜3在长度方向上的延展率与正极片的厚度之比为(0.9-3.7)：1；隔膜在宽度方向上的延展率与正极片的厚度之比为(0.9-3.7)：1，实现锂离子电池的安全性能的改善。在包含本申请电极组件的锂离子电池的应用过程中，当电极组件受到机械滥用时，可以减少正极集流体2与负极活性层1的接触，减少短路点的产生，从而减少热失控发生的概率，可以使包含本申请电极组件的锂离子电池具有较高的安全性能。
在本申请的一些实施方式中，为了更好的提高锂离电池的安全性能，正极片的厚度为60-120mm；和/或，
隔膜3在长度方向上的延展率为60-220％；
隔膜3在宽度方向上的延展率为60-220％。
进一步地，当隔膜3在长度方向上的延展率与正极片的厚度之比为(1.2-3.7)：1；隔膜3在宽度方向上的延展率与正极片的厚度之比为(1.2-3.7)： 1，锂离子电池具有更高的安全性能。
在本申请的一些实施方式中，隔膜3在长度方向上的延展率为100-220％；隔膜3在宽度方向上的延展率为100-220％。
在本申请的一些实施方式中，为了更好的提高锂离子电池的安全性能，隔膜3包括聚烯烃多孔隔膜基材以及设置在聚烯烃多孔隔膜基材的至少一个功能表面的涂覆层。
可以理解为，本申请的隔膜3，可以通过在聚烯烃多孔隔膜基材的任一功能表面设置涂覆层获得，也可以通过在聚烯烃多孔隔膜基材的两个功能表面皆设置涂覆层获得。其中，隔膜3的延展率主要与聚烯烃多孔隔膜基材的延展率有关。
在本申请的一些实施方式中，聚烯烃多孔隔膜基材的厚度为1-20μm。
本申请中，若聚烯烃多孔隔膜基材的厚度过厚，过厚的聚烯烃多孔隔膜基材会使得电极组件过厚，不利于锂离子电池能量密度的优化，若聚烯烃多孔隔膜基材的厚度过薄，过薄的聚烯烃多孔隔膜基材在锂离子电池的长期运行中容易发生损坏，缩短了锂离子电池的使用寿命。本申请中，聚烯烃多孔隔膜基材的厚度为1-20μm，在此范围内可以使锂离子电池兼具好的能量密度以及较长的使用寿命。
在本申请的一些实施方式中，聚烯烃多孔隔膜基材的孔隙率为20-60％。具体地，满足上述孔隙率的聚烯烃多孔隔膜基材不仅能够满足锂离子电池的电性能，还有利于改善聚烯烃多孔隔膜基材的机械性能，延长锂离子电池的使用寿命，
在本申请的一些实施方式中，聚烯烃多孔隔膜基材的透气值为30-250sec/100cc。
本申请中，聚烯烃多孔隔膜基材的透气值指的是，在0.25MPa的压力下，100cc的空气通过聚烯烃多孔隔膜基材所需要的时间。当聚烯烃多孔隔膜基材的透气值过小时，聚烯烃多孔隔膜基材容易透过其他的物质，锂离子电池的自放电大，当聚烯烃多孔隔膜基材的透气值过大时，容易使锂离子电池的内阻过大，影响锂离子电池的电性能。本申请中，当聚烯烃多孔隔膜基材的透气值为30-250sec/100cc时，可以使锂离子电池兼具良好的电性能以及较小的自放电性能。
在本申请的一些实施方式中，为了在不影响锂离子电池的能量密度的前提下，进一步提高锂离子电池的安全性能，涂覆层的厚度为0.5-12μm。
在本申请的一些实施方式中，涂覆层包括无机颗粒与聚合物中的至少一种。
本申请的无机颗粒可以选自本领域常用的无机颗粒，例如，可以选自氧化铝、二氧化硅、勃姆石、氧化锌、氧化镁、二氧化锆、氧化钛、氧化钡、氧化钙、氮化铝、氮化钛、氮化硅、氮化硼、氢氧化铝、氢氧化镁和硫酸钡中的至少一种。
本申请的聚合物可以选自本领域常用的聚合物，例如，可以选自聚偏氟乙烯、聚偏氟乙烯-六氟丙烯共聚物、羧甲基纤维素钠、聚丙烯酸酯、聚丙烯腈、聚乙烯醇、丁苯橡胶、聚氨酯、乙烯-丙烯酸共聚物、聚甲基丙烯酸甲酯、聚酰亚胺、芳纶、聚苯乙烯和聚酯中至少一种。
本申请中，若涂覆层只包括无机颗粒，称为无机涂覆层；若聚合物只包括聚合物，称为有机涂覆层；若涂覆层同时包括有机颗粒和聚合物，称为复合涂覆层。本申请的隔膜，可以通过在聚烯烃多孔隔膜基材的任一功能表面设置无机涂覆层、有机涂覆层和复合涂覆层中的至少一种得到，也可以通过在聚烯烃多孔隔膜基材的两个功能表面设置无机涂覆层、有机涂覆层和复合涂覆层中的至少一种得到。
当在聚烯烃多孔隔膜基材的某一功能表面设置无机涂覆层、有机涂覆层和复合涂覆层中的至少两种时，无机涂覆层、有机涂覆层和复合涂覆层中的至少两种可以层叠设置，无机涂覆层、有机涂覆层和复合涂覆层中的至少两种也可以在聚烯烃多孔隔膜基材的功能表面并列设置。并且，本申请对层叠设置的顺序不做特别限定，对并列设置的顺序也不做特别限定。
在一些实施方式中，无机涂覆层设置在聚烯烃多孔隔膜基材的某一功能表面，有机涂覆层和/或复合涂覆层设置在无机涂覆层远离聚烯烃多孔隔膜基材的功能表面。
本申请的第二方面提供一种锂离子电池，包含上述的电极组件。
将上述的电极组件置于外包装中，对外包装进行顶封和侧封后，烘烤水分，向外包装中注入电解液，然后依次经真空封装、静置、化成、整形工序，得到锂离子电池。
本申请的锂离子电池，由于包含上述的电极组件，因此具有更为优异的安全性能。
以下，将结合具体的实施例对本申请的技术方案进行说明。
实施例1
本实施例的锂离子电池通过以下步骤制备得到：
1、隔膜的制备
在聚烯烃多孔隔膜基材的一个功能表面采用凹版涂覆设置氧化铝陶瓷层，然后在聚烯烃多孔隔膜基材的另一个功能表面采用凹版涂覆设置聚偏氟乙烯(PVDF)胶层，在氧化铝陶瓷层远离聚烯烃多孔隔膜基材的功能表面采用凹版涂覆设置PVDF胶层，得到隔膜；
其中，聚烯烃多孔隔膜基材的厚度为5μm，聚烯烃多孔隔膜基材的孔隙率为32％，聚烯烃多孔隔膜基材的透气值为145sec/100cc，氧化铝陶瓷层的厚度为2μm，PVDF胶层的厚度为1μm，隔膜在长度方向上的延展率为180％，隔膜在宽度方向上的延展率为165％。
2、正极片的制备
将正极活性材料钴酸锂、导电剂导电炭黑、粘接剂PVDF按照97.2：1.5：1.3的质量比加入到搅拌罐中，再加入NMP溶液，经充分搅拌得到正极活性浆料，将正极活性浆料分别涂布在正极集流体铝箔的两个功能表面，然后进行烘干除去溶剂，最后依次进行辊压、分切和制片工序得到正极片；
其中，正极片的厚度为90mm。
3、负极片的制备
将负极活性材料石墨、导电剂乙炔黑、粘接剂羧甲基纤维素钠按照97：1.5：1.5的质量比加入到搅拌罐中，再加入去离子水，经充分搅拌得到负极活性浆料，将负极活性浆料分别涂布在负极集流体铜箔的两个功能表面，然后进行烘干除去水份，最后依次进行辊压、分切和制片工序得到负极片。
4、电极组件的制备
将步骤1获得的隔膜、步骤2获得的正极片以及步骤3获得的负极片，按照正极片、隔膜和负极片的顺序进行层叠，然后进行卷绕得到电极组件；
其中，隔膜在长度方向上的延展率与正极片的厚度之比为2：1，隔膜在 宽度方向上的延展率与正极片的厚度之比为1.83：1。
5、锂离子电池的制备
将步骤4获得的电极组件置于外包装铝塑膜中，对铝塑膜进行顶封和侧封后，烘烤除去水份，向外包装中注入电解液，经正空封装、静置、化成以及整形得到锂离子电池；
其中，电解液通过以下步骤制备得到：在充满氩气的手套箱中(H 2O＜0.1ppm，O 2＜0.1ppm)，将碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸二乙酯(DEC)、丙酸正丙酯混合均匀，然后往其中加入1.2mol/L的充分干燥的六氟磷酸锂(LiPF 6)，溶解于非水有机溶剂中，搅拌均匀，经过水分和游离酸检测合格后，得到基础电解液。
本实施例步骤1中隔膜在长度方向上的延展率与隔膜在宽度方向上的延展率为通过包括以下步骤的方法测试获得：
将隔膜裁切成宽度1.5cm，长度大于5cm的长方形样条，样条长边的延伸方向与隔膜3的长度方向一致，使样条边缘平滑无缺口(防止缺陷影响测试结果)。将上述样条夹在万能拉力机上下夹具中间，样条的长轴与夹具的中心线重合，拉力机上下夹具之间的距离为隔膜的指定距离，隔膜长度方向上的指定距离为5cm，在100mm/min拉伸试验速度下，沿样条的长度方向对样条进行拉伸，直至隔膜破裂，获得隔膜在长度方向上的指定距离的增加量，计算隔膜在长度方向的延展率。
隔膜在宽度方向的延展率测试方法与在长度方向上的延展率的测试方法基本相同，唯一不同的是，样条长边的延伸方向与隔膜3的宽度方向一致。
实施例2
本实施例的锂离子电池的制备步骤与实施例1的锂离子电池的制备步骤的不同之处在于：
步骤1中，在聚烯烃多孔隔膜基材的两个功能表面采用凹版涂覆设置氧化铝陶瓷层，分别在氧化铝陶瓷层远离聚烯烃多孔隔膜基材的功能表面采用凹版涂覆设置PVDF胶层，得到隔膜。
本实施例中，隔膜在长度方向上的延展率、隔膜在宽度方向上的延展率以及正极片的厚度与实施例1相同。
本实施例步骤1中隔膜在长度方向上的延展率与隔膜在宽度方向上的延展率的测试方法与实施例1相同。
实施例3
本实施例的锂离子电池的制备步骤与实施例1的锂离子电池的制备步骤的不同之处在于：
步骤1中，将氧化铝与PVDF进行混合得到混合浆料，分别将混合浆料采用凹版涂覆设置在聚烯烃多孔隔膜基材的两个功能表面，得到涂覆层以及隔膜；
其中，涂覆层的厚度为4μm，氧化铝与PVDF的质量比为9：1。
本实施例中，隔膜在长度方向上的延展率、隔膜在宽度方向上的延展率以及正极片的厚度与实施例1相同。
本实施例步骤1中隔膜在长度方向上的延展率与隔膜在宽度方向上的延展率的测试方法与实施例1相同。
实施例4
本实施例的锂离子电池的制备步骤与实施例1的锂离子电池的制备步骤的不同之处在于：
步骤1中，采用了不同于实施例1中的聚烯烃多孔隔膜基材，使得隔膜在长度方向上的延展率为105％，隔膜在宽度方向上的延展率为95％；
步骤2中，正极片的厚度为75mm。
本实施例中隔膜在长度方向上的延展率与正极片的厚度之比为1.4：1，隔膜在宽度方向上的延展率与正极片的厚度之比为1.27：1。
本实施例步骤1中隔膜在长度方向上的延展率与隔膜在宽度方向上的延展率的测试方法与实施例1相同。
实施例5
本实施例的锂离子电池的制备步骤与实施例2的锂离子电池的制备步骤的不同之处在于：
步骤1中，采用了不同于实施例2中聚烯烃多孔隔膜基材，其中，聚烯 烃多孔隔膜基材的厚度为7μm，隔膜在宽度方向上的延展率为175％。
本实施例中，隔膜在宽度方向上的延展率与正极片的厚度之比为1.94：1。
本实施例中，隔膜在长度方向上的延展率以及正极片的厚度与实施例2相同。
本实施例步骤1中隔膜在长度方向上的延展率与隔膜在宽度方向上的延展率的测试方法与实施例2相同。
实施例6
本实施例的锂离子电池的制备步骤与实施例1的锂离子电池的制备步骤的不同之处在于：
步骤1中，采用了孔隙率和透气值不同于实施例1中的聚烯烃多孔隔膜基材，其中，聚烯烃多孔隔膜基材的孔隙率为39％，聚烯烃多孔隔膜基材的透气值为105sec/100cc。
本实施例中，隔膜在长度方向上的延展率以及正极片的厚度与实施例1相同。
本实施例步骤1中隔膜在长度方向上的延展率与隔膜在宽度方向上的延展率的测试方法与实施例2相同。
实施例7
本实施例的锂离子电池的制备步骤与实施例1的锂离子电池的制备步骤的不同之处在于：
步骤1中，采用了延展率不同于实施例1中的聚烯烃多孔隔膜基材，使得隔膜在长度方向上的延展率为180％，隔膜在宽度方向上的延展率为180％；
步骤2中，正极片的厚度为60mm。
本实施例中隔膜在长度方向上的延展率与正极片的厚度之比为3：1，隔膜在宽度方向上的延展率与正极片的厚度之比为3：1。
本实施例步骤1中隔膜在长度方向上的延展率与隔膜在宽度方向上的延展率的测试方法与实施例1相同。
实施例8
本实施例的锂离子电池的制备步骤与实施例1的锂离子电池的制备步骤的不同之处在于：
步骤1中，采用了延展率不同于实施例1中的聚烯烃多孔隔膜基材，使得隔膜在长度方向上的延展率为110％，隔膜在宽度方向上的延展率为110％；
本实施例中隔膜在长度方向上的延展率与正极片的厚度之比为1.2：1，隔膜在宽度方向上的延展率与正极片的厚度之比为1.2：1。
本实施例步骤1中隔膜在长度方向上的延展率与隔膜在宽度方向上的延展率的测试方法与实施例1相同。
实施例9
本实施例的锂离子电池的制备步骤与实施例1的锂离子电池的制备步骤的不同之处在于：
步骤1中，采用了延展率不同于实施例1中的聚烯烃多孔隔膜基材，使得隔膜在长度方向上的延展率为81％，隔膜在宽度方向上的延展率为81％；
本实施例中隔膜在长度方向上的延展率与正极片的厚度之比为0.9：1，隔膜在宽度方向上的延展率与正极片的厚度之比为0.9：1。
本实施例步骤1中隔膜在长度方向上的延展率与隔膜在宽度方向上的延展率的测试方法与实施例1相同。
实施例10
本实施例的锂离子电池的制备步骤与实施例1的锂离子电池的制备步骤的不同之处在于：
步骤1中，采用了延展率不同于实施例1中的聚烯烃多孔隔膜基材，使得隔膜在长度方向上的延展率为220％，隔膜在宽度方向上的延展率为220％；
本实施例中隔膜在长度方向上的延展率与正极片的厚度之比为3.7：1，隔膜在宽度方向上的延展率与正极片的厚度之比为3.67:1。
本实施例步骤1中隔膜在长度方向上的延展率与隔膜在宽度方向上的延展率的测试方法与实施例1相同。
实施例11
本实施例的锂离子电池的制备步骤与实施例1的锂离子电池的制备步骤的不同之处在于：
步骤2中，正极片的厚度为120mm；
本实施例中隔膜在长度方向上的延展率与正极片的厚度之比为1.5：1，隔膜在宽度方向上的延展率与正极片的厚度之比为1.375：1。
本实施例步骤1中隔膜在长度方向上的延展率与隔膜在宽度方向上的延展率的测试方法与实施例1相同。
实施例12
本实施例的锂离子电池的制备步骤与实施例7的锂离子电池的制备步骤的不同之处在于：
步骤1中，采用了延展率不同于实施例7中的聚烯烃多孔隔膜基材，使得隔膜在长度方向上的延展率为60％，隔膜在宽度方向上的延展率为60％；
本实施例中隔膜在长度方向上的延展率与正极片的厚度之比为1：1，隔膜在宽度方向上的延展率与正极片的厚度之比为1：1。
本实施例步骤1中隔膜在长度方向上的延展率与隔膜在宽度方向上的延展率的测试方法与实施例7相同。
实施例13
本实施例的锂离子电池的制备步骤与实施例1的锂离子电池的制备步骤的不同之处在于：
步骤1中，采用了延展率不同于实施例1中的聚烯烃多孔隔膜基材，使得隔膜在长度方向上的延展率为220％，隔膜在宽度方向上的延展率为220％；
本实施例中隔膜在长度方向上的延展率与正极片的厚度之比为2.44：1，隔膜在宽度方向上的延展率与正极片的厚度之比为2.44：1。
本实施例步骤1中隔膜在长度方向上的延展率与隔膜在宽度方向上的延展率的测试方法与实施例1相同。
实施例14
本实施例的锂离子电池的制备步骤与实施例1的锂离子电池的制备步骤 的不同之处在于：
步骤1中，采用了延展率不同于实施例1中的聚烯烃多孔隔膜基材，使得隔膜在长度方向上的延展率为100％，隔膜在宽度方向上的延展率为100％；
步骤2中，正极片的厚度为80mm；
本实施例中隔膜在长度方向上的延展率与正极片的厚度之比为1.25：1，隔膜在宽度方向上的延展率与正极片的厚度之比为1.25：1。
本实施例步骤1中隔膜在长度方向上的延展率与隔膜在宽度方向上的延展率的测试方法与实施例1相同。
对比例1
本对比例的锂离子电池的制备步骤与实施例1的锂离子电池的制备步骤的不同之处在于：
步骤1中采用了不同于实施例1的聚烯烃多孔隔膜基材，使得隔膜在长度方向上的延展率为58％，隔膜在宽度方向上的延展率为62％；
本对比例中，隔膜在长度方向上的延展率与正极片的厚度之比为0.64：1，隔膜在宽度方向上的延展率与正极片的厚度之比为0.69：1。
本对比例中，正极片的厚度与实施例1相同。
本对比例步骤1中隔膜在长度方向上的延展率与隔膜在宽度方向上的延展率的测试方法与实施例1相同。
对比例2
本对比例的锂离子电池的制备步骤与实施例1的锂离子电池的制备步骤的不同之处在于：
步骤1中采用了不同于实施例1的聚烯烃多孔隔膜基材，使得隔膜在长度方向上的延展率为92％，隔膜在宽度方向上的延展率为89％；
步骤2中正极片的厚度为120mm。
本对比例中，隔膜在长度方向上的延展率与正极片的厚度之比为0.77：1，隔膜在宽度方向上的延展率与正极片的厚度之比为0.74：1。
本对比例步骤1中隔膜在长度方向上的延展率与隔膜在宽度方向上的延展率的测试方法与实施例1相同。
针刺性能测试
对实施例和对比例中的锂离子电池按标准充放电模式进行充电，充满电后对锂离子电池进行针刺测试，使用直径为3mm的钢针，将锂离子电池至于水平面，钢针以150mm/s的速度穿过锂离子电池中心位置，并留在锂离子电池内保持10min，若锂离子电池不起火、不爆炸则认为通过测试。每个实施例和对比例的锂离子电池各测试100只，计算针刺通过率，测试结果见表1。
图3为锂离子电池针刺测试的示意图。如图3所示，对锂离子电池进行针刺测试时，钢针依次通过负极活性层1、负极集流体4、负极活性层1、隔膜3、正极活性层5和正极集流体2，若锂离子电池发生短路，离子电池的内部电流温度会升高，进而会引起锂离子电池起火，说明锂离子电池的针刺测试结果为不通过。
表1
项目 针刺通过率/％
实施例1 95/100
实施例2 99/100
实施例3 91/100
实施例4 87/100
实施例5 100/100
实施例6 94/100
实施例7 100/100
实施例8 83/100
实施例9 69/100
实施例10 100/100
实施例11 89/100
实施例12 75/100
实施例13 100/100
实施例14 85/100
对比例1 19/100
对比例2 27/100
从表1可以看出，本申请的电极组件用于锂离子电池中，可以提高锂离子电池的安全性能。证明通过匹配电极组件中隔膜的延展率与正极片的厚度，在针刺测试时，能够减少正极与负极短路点的产生，有效减少因短路而产生的热量，从而实现电池安全性能的提升。
进一步地，从实施例1-8、10-11、13-14可以看出，当隔膜在长度方向上的延展率与正极片的厚度之比为(1.2-3.7)：1；隔膜在宽度方向上的延展率与正极片的厚度之比为(1.2-3.7)：1，锂离子电池具有更好的安全性能，针刺通过率大于等于83％。
本说明书中的各个实施例均采用相关的方式描述，各个实施例之间相同相似的部分互相参见即可，每个实施例重点说明的都是与其它实施例的不同之处。以上仅为本申请的较佳实施例而已，并非用于限定本申请的保护范围。凡在本申请的精神和原则之内所作的任何修改、等同替换、改进等，均包含在本申请的保护范围内。

Claims (10)

  1. 一种电极组件，其中，包括正极片、负极片和隔膜，所述隔膜设置于所述正极片和所述负极片之间；
    所述隔膜在长度方向上的延展率与所述正极片的厚度之比为(0.9-3.7)：1；
    所述隔膜在宽度方向上的延展率与所述正极片的厚度之比为(0.9-3.7)：1。
  2. 根据权利要求1所述的电极组件，其中，所述正极片的厚度为60-120mm；和/或，
    所述隔膜在长度方向上的延展率为60-220％；
    所述隔膜在宽度方向上的延展率为60-220％。
  3. 根据权利要求1或2所述的电极组件，其中，所述隔膜在长度方向上的延展率与所述正极片的厚度之比为(1.2-3.7)：1；
    所述隔膜在宽度方向上的延展率与所述正极片的厚度之比为(1.2-3.7)：1。
  4. 根据权利要求3所述的电极组件，其中，所述隔膜在长度方向上的延展率为100-220％；
    所述隔膜在宽度方向上的延展率为100-220％。
  5. 根据权利要求1-4任一项所述的电极组件，其中，所述隔膜包括聚烯烃多孔隔膜基材以及设置在所述聚烯烃多孔隔膜基材的至少一个功能表面的涂覆层。
  6. 根据权利要求5所述的电极组件，其中，所述聚烯烃多孔隔膜基材的厚度为1-20μm；和/或，
    所述聚烯烃多孔隔膜基材的孔隙率为20-60％。
  7. 根据权利要求5-6任一项所述的电极组件，其中，所述聚烯烃多孔隔膜基材的透气值为30-250sec/100cc。
  8. 根据权利要求5-7任一项所述的电极组件，其中，所述涂覆层的厚度为0.5-12μm。
  9. 根据权利要求5-8任一项所述的电极组件，其中，所述涂覆层包括无机颗粒与聚合物中的至少一种。
  10. 一种锂离子电池，其中，包含权利要求1-9任一项所述的电极组件。
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116454404A (zh) * 2023-06-20 2023-07-18 宁德时代新能源科技股份有限公司 二次电池及其制备方法与电池模块、电池包、用电装置

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112862222A (zh) * 2021-03-26 2021-05-28 中国建设银行股份有限公司 空调回风温度的预测方法、异常监控方法和相关装置
CN113809475A (zh) * 2021-09-15 2021-12-17 珠海冠宇电池股份有限公司 一种电极组件及其应用

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012182084A (ja) * 2011-03-02 2012-09-20 Toyota Motor Corp 非水電解質二次電池
JP2015053237A (ja) * 2013-09-09 2015-03-19 トヨタ自動車株式会社 非水電解液二次電池
CN111416086A (zh) * 2020-03-04 2020-07-14 华为技术有限公司 电池隔膜及其制备方法、电池和终端
CN113809475A (zh) * 2021-09-15 2021-12-17 珠海冠宇电池股份有限公司 一种电极组件及其应用
WO2022001987A1 (zh) * 2020-06-28 2022-01-06 华为技术有限公司 二次电池和终端

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4748840B2 (ja) * 2000-09-29 2011-08-17 シャープ株式会社 リチウムポリマー二次電池
CN102124595B (zh) * 2009-06-30 2013-10-02 松下电器产业株式会社 非水电解质二次电池用负极及其制造方法以及非水电解质二次电池
JP6423724B2 (ja) * 2015-01-26 2018-11-14 旭化成株式会社 電池用セパレータ、及び非水電解液電池
JP6383038B1 (ja) * 2017-03-22 2018-08-29 株式会社東芝 二次電池、電池パック及び車両
JP2019067492A (ja) * 2017-09-28 2019-04-25 三洋電機株式会社 非水電解質二次電池用セパレータ及び非水電解質二次電池

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012182084A (ja) * 2011-03-02 2012-09-20 Toyota Motor Corp 非水電解質二次電池
JP2015053237A (ja) * 2013-09-09 2015-03-19 トヨタ自動車株式会社 非水電解液二次電池
CN111416086A (zh) * 2020-03-04 2020-07-14 华为技术有限公司 电池隔膜及其制备方法、电池和终端
WO2022001987A1 (zh) * 2020-06-28 2022-01-06 华为技术有限公司 二次电池和终端
CN113809475A (zh) * 2021-09-15 2021-12-17 珠海冠宇电池股份有限公司 一种电极组件及其应用

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116454404A (zh) * 2023-06-20 2023-07-18 宁德时代新能源科技股份有限公司 二次电池及其制备方法与电池模块、电池包、用电装置
CN116454404B (zh) * 2023-06-20 2023-09-22 宁德时代新能源科技股份有限公司 二次电池及其制备方法与电池模块、电池包、用电装置

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