WO2022036721A1 - 电极组件、电池单体、电池及制造电极组件的方法和装置 - Google Patents

电极组件、电池单体、电池及制造电极组件的方法和装置 Download PDF

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Publication number
WO2022036721A1
WO2022036721A1 PCT/CN2020/110628 CN2020110628W WO2022036721A1 WO 2022036721 A1 WO2022036721 A1 WO 2022036721A1 CN 2020110628 W CN2020110628 W CN 2020110628W WO 2022036721 A1 WO2022036721 A1 WO 2022036721A1
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WIPO (PCT)
Prior art keywords
pole piece
barrier layer
electrode
positive
electrode assembly
Prior art date
Application number
PCT/CN2020/110628
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English (en)
French (fr)
Inventor
喻鸿钢
史松君
金海族
宋书涛
陈冰
杜鑫鑫
Original Assignee
宁德时代新能源科技股份有限公司
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Application filed by 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to KR1020227030155A priority Critical patent/KR102635995B1/ko
Priority to BR112022017318A priority patent/BR112022017318A2/pt
Priority to CA3171539A priority patent/CA3171539A1/en
Priority to EP20949928.4A priority patent/EP4075563A4/en
Priority to JP2022552951A priority patent/JP2023516411A/ja
Priority to CN202080096370.3A priority patent/CN115066782A/zh
Priority to PCT/CN2020/110628 priority patent/WO2022036721A1/zh
Publication of WO2022036721A1 publication Critical patent/WO2022036721A1/zh
Priority to US18/055,623 priority patent/US11843119B2/en
Priority to US18/470,231 priority patent/US20240014401A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0583—Construction or manufacture of accumulators with folded construction elements except wound ones, i.e. folded positive or negative electrodes or separators, e.g. with "Z"-shaped electrodes or separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • 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
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/103—Primary casings; Jackets or wrappings characterised by their shape or physical structure prismatic or rectangular
    • 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
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • H01M50/207—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape
    • H01M50/209—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape adapted for prismatic or rectangular cells
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present application relates to the field of batteries, and in particular, to an electrode assembly, a battery cell, a battery, and a method and apparatus for manufacturing the electrode assembly.
  • a rechargeable battery which can be called a secondary battery, refers to a battery that can continue to be used by activating the active material by charging after the battery is discharged.
  • Rechargeable batteries are widely used in electronic devices such as cell phones, laptops, battery cars, electric cars, electric planes, electric boats, electric toy cars, electric toy boats, electric toy planes, and power tools, among others.
  • Rechargeable batteries may include nickel-cadmium batteries, nickel-hydrogen batteries, lithium-ion batteries, secondary alkaline zinc-manganese batteries, and the like.
  • lithium-ion batteries are generally used in automobiles.
  • As a rechargeable battery lithium-ion batteries have the advantages of small size, high energy density, high power density, many cycles and long storage time.
  • the rechargeable battery includes an electrode assembly and an electrolyte solution.
  • the electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator between the positive electrode sheet and the negative electrode sheet.
  • the positive pole piece can also be called a cathode pole piece. Both surfaces of the positive pole piece have positive active material layers.
  • the positive active material of the positive active material layer can be lithium manganate, lithium cobaltate, lithium iron phosphate or nickel. Lithium cobalt manganate; the negative pole piece can also be called an anode pole piece, and both surfaces of the negative pole piece have a negative electrode active material layer, for example, the negative electrode active material of the negative electrode active material layer can be graphite or silicon.
  • Lithium precipitation is a common abnormal phenomenon of lithium batteries, which will affect the charging efficiency and energy density of lithium ions.
  • lithium precipitation is serious, lithium crystals can also be formed, and lithium crystals can pierce the isolation film and cause thermal runaway of internal short circuit, which is a serious hazard. battery safety.
  • aspects of the present application provide an electrode assembly, a battery cell, a battery, and a method and apparatus for manufacturing an electrode assembly that overcome the above-mentioned problems or at least partially solve the above-mentioned problems.
  • a first aspect of the present application provides an electrode assembly, which includes: a positive electrode piece and a negative electrode piece, and the positive electrode piece and the negative electrode piece are wound or stacked to form a bending region;
  • the bending region has a barrier layer, wherein at least a part of the barrier layer is located between adjacent positive electrode pieces and negative electrode pieces for blocking at least a part of ions protruding from the positive electrode pieces from inserting into the negative electrode pieces in the bending region.
  • a barrier layer between the adjacent positive electrode and negative electrode, during charging, at least a part of the ions released from the positive active material layer of the positive electrode in the bending region is blocked by the barrier, so that the ions blocked by the barrier.
  • the ions cannot be embedded in the negative electrode active material layer of the negative electrode plate adjacent to the positive electrode plate in the bending area, so that when the negative electrode active material falls off the negative electrode plate, the occurrence of lithium precipitation is reduced, the safety performance of the battery cell is improved, and the battery cell life.
  • the electrode assembly further includes a separator for separating adjacent positive and negative electrode pieces, a barrier layer is attached to one surface or both surfaces of the positive electrode piece, and/or, the The barrier layer is attached to one or both surfaces, and/or the barrier layer is attached to one or both surfaces of the separator. In this way, the positional movement of the barrier layer during use of the electrode assembly can be reduced.
  • the electrode assembly further includes a separator for separating adjacent positive electrode pieces and negative electrode pieces, and the barrier layer is independent between the adjacent positive electrode pieces and the separator in the bending region, or, the barrier layer Between the adjacent negative pole pieces and the separator independent of the bending area. In this way, the installation of the barrier layer can be facilitated.
  • the porosity of the barrier layer is less than the porosity of the isolation membrane. In this way, the barrier layer can more effectively block the passage of lithium ions.
  • the electrode assembly includes a positive pole piece and a negative pole piece, and a positive pole piece and a negative pole piece are compacted and rolled to form a rolled structure, wherein at least the innermost part of the bending area is There is a barrier layer between the adjacent positive pole pieces and negative pole pieces. In this way, the lithium deposition phenomenon between the innermost adjacent positive electrode and negative electrode can be reduced, and the safety performance can be improved.
  • the innermost pole piece in the bending region is a negative pole piece. In this way, the utilization efficiency of the active material of the positive electrode sheet can be improved.
  • the barrier layers are a plurality of discontinuous layers, and the plurality of discontinuous barrier layers are distributed at intervals along the bending direction, or the plurality of discontinuous barrier layers are distributed at intervals along a direction perpendicular to the bending direction. In this way, the passage of some lithium ions can be blocked, the occurrence of lithium precipitation can be reduced, and the energy density of the electrode assembly can be guaranteed.
  • the thickness of the barrier layer is 2-200 microns; or 5-100 microns. In this way, both the safety of the electrode assembly and the energy density of the electrode assembly can be ensured.
  • the barrier layer has at least one through hole.
  • the porosity of the barrier layer is 10%-70%; or 20%-60%. In this way, both the safety of the electrode assembly and the energy density of the electrode assembly can be ensured.
  • the thickness of the barrier layer is A microns
  • the porosity of the barrier layer is B, where A and B satisfy the following relationship: 3.5 microns ⁇ A/B ⁇ 2000 microns; or 7 microns ⁇ A/B ⁇ 1000 microns. In this way, both the safety of the electrode assembly and the energy density of the electrode assembly can be ensured.
  • both ends of the negative electrode active material layer of the negative electrode sheet along the direction perpendicular to the bending direction are beyond the corresponding ends of the positive electrode active material layer of the positive electrode sheet. In this way, the energy density of the electrode assembly can be guaranteed.
  • the barrier layer includes two ends along a direction perpendicular to the bending direction, and one or both ends of the barrier layer extend beyond the positive active material layer of the positive electrode sheet. In this way, the passage of more lithium ions can be blocked, and the occurrence of lithium precipitation can be reduced.
  • the barrier layer includes two ends along a direction perpendicular to the bending direction, and the negative electrode active material layer of the negative electrode sheet extends beyond one or both ends of the barrier layer. In this way, the passage of some lithium ions can be blocked, the occurrence of lithium precipitation can be reduced, and the energy density of the electrode assembly can be guaranteed.
  • the blocking layer is disposed opposite the portion of the negative pole piece where the curvature is the largest. In this way, the part with the largest curvature can be made not to insert lithium ions or to insert a small part of lithium ions, thereby reducing the occurrence of lithium precipitation.
  • the barrier layer includes at least one of the following: an inorganic oxide, a binder, and an adhesive tape.
  • both ends of the barrier layer extending along the bending direction are located in the bending region. In this way, the passage of more lithium ions can be blocked, and the occurrence of lithium precipitation can be reduced.
  • the electrode assembly has a flat region connected to the bent region
  • One end of the barrier layer extending along the bending direction is located in the straight area, and the other end is located in the bending area; or, both ends of the barrier layer extending along the bending direction are located in the straight area.
  • a second aspect of the present application provides a battery cell, comprising: a casing, a cover plate, and at least one electrode assembly of the above-mentioned embodiments, wherein,
  • the housing has an accommodating cavity and an opening, and the electrode assembly is accommodated in the accommodating cavity;
  • the cover plate is used to close the opening of the housing.
  • a third aspect of the present application provides a battery, which includes a case and at least one battery cell, and the battery cell is accommodated in the case.
  • a fourth aspect of the present application provides a method for manufacturing an electrode assembly, comprising:
  • the positive pole piece and the negative pole piece are wound or stacked, and a bending area is formed, wherein, there is a barrier layer in the bending area, and at least a part of the barrier layer is located between adjacent positive pole pieces and negative pole pieces. It is used to block at least a part of the ions protruding from the positive pole piece from inserting into the negative pole piece in the bending area.
  • a separator is provided for separating adjacent positive and negative electrode sheets, and the separator, positive and negative electrode sheets are wound or laminated together.
  • the method prior to winding or laminating the separator, positive pole piece, and negative pole piece together, the method further includes: placing a barrier layer on one or both surfaces of the positive pole piece or the negative pole piece.
  • placing the barrier layer on one or both surfaces of the positive electrode sheet or the negative electrode sheet specifically includes: pasting or coating the barrier layer on one or both surfaces of the positive electrode sheet or the negative electrode sheet .
  • a fifth aspect of the present application provides a device for manufacturing an electrode assembly, including:
  • a first providing device for providing a positive pole piece
  • barrier layer in the bending region, wherein at least a part of the barrier layer is located between the adjacent positive electrode and negative electrode, and is used to block at least a part of the ions protruding from the positive electrode from inserting into the negative electrode in the bending region.
  • the electrode assembly manufacturing equipment further includes a fourth providing device for providing a separator for separating adjacent positive electrode and negative electrode plates, and the assembling device is also used for combining the positive electrode and negative electrode.
  • the sheet and the separator are wound or laminated to form the bend region.
  • there are two third providing devices and the two third providing devices are used to respectively provide a barrier layer, and stick or coat the barrier layer on both surfaces of the positive electrode sheet or the negative electrode sheet.
  • a sixth aspect of the present application provides a powered device, wherein the powered device is configured to receive power provided by a slave battery.
  • FIG. 1 is a schematic three-dimensional structural diagram of an electrode assembly according to an embodiment of the application
  • FIG. 2 is a schematic structural diagram of a cross-section of the electrode assembly of FIG. 1 along a direction perpendicular to the winding axis K;
  • FIG. 3 is a schematic partial structure diagram of an electrode assembly in its bending region according to an embodiment of the application
  • FIG. 4 is a schematic structural diagram of the barrier layer distribution after the bending region of the electrode assembly according to another embodiment of the present application is flattened;
  • FIG. 5 is a schematic structural diagram of another barrier layer distribution after the bending region of the electrode assembly according to another embodiment of the present application is flattened;
  • FIG. 6 is a schematic structural diagram of another barrier layer distribution after the bending region of the electrode assembly according to another embodiment of the present application is flattened;
  • FIG. 7 is a schematic structural diagram of a negative pole piece according to another embodiment of the application.
  • FIG. 8 is a schematic structural diagram of a positive electrode piece in another embodiment of the present application.
  • Fig. 9 is the cross-sectional structure schematic diagram of A-A direction in Fig. 8.
  • FIG. 10 is a schematic diagram of a cross-sectional structure in the direction B-B in FIG. 8;
  • FIG. 11 is a schematic structural diagram of a cross section of a flat body-shaped electrode assembly perpendicular to the winding axis according to another embodiment of the application;
  • FIG. 12 is a schematic structural diagram of a cross-section of another flat-shaped electrode assembly perpendicular to the winding axis according to another embodiment of the application;
  • FIG. 13 is a schematic structural diagram of a cross-section of another flat-body-shaped electrode assembly perpendicular to the winding axis according to another embodiment of the application;
  • FIG. 14 is a schematic structural diagram of a cross-section of another flat-body-shaped electrode assembly perpendicular to the winding axis according to another embodiment of the application;
  • FIG. 15 is a schematic structural diagram of a cross-section of another flat body-shaped electrode assembly perpendicular to the winding axis according to another embodiment of the application;
  • 16 is a schematic structural diagram of a cross-section of another flat-body-shaped electrode assembly perpendicular to the winding axis according to another embodiment of the application;
  • 17 is a schematic structural diagram of a cross-section of another flat-shaped electrode assembly perpendicular to the winding axis according to another embodiment of the application;
  • FIG. 18 is a schematic structural diagram of a cross section of a flat-shaped electrode assembly perpendicular to the winding axis according to another embodiment of the application;
  • FIG. 19 is a schematic structural diagram of a cross section of a flat body-shaped electrode assembly perpendicular to the winding axis according to another embodiment of the application.
  • 20 is a schematic structural diagram of a battery cell according to another embodiment of the present application.
  • 21 is a schematic structural diagram of a battery module according to another embodiment of the present application.
  • 22 is a schematic structural diagram of a battery according to another embodiment of the application.
  • FIG. 23 is a schematic structural diagram of an electrical device according to another embodiment of the application.
  • 24 is a schematic flowchart of a method for manufacturing an electrode assembly according to another embodiment of the present application.
  • FIG. 25 is a schematic structural diagram of an apparatus for manufacturing an electrode assembly according to another embodiment of the present application.
  • the terms “installed”, “connected” and “connected” should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication between two elements.
  • installed should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication between two elements.
  • the positive pole piece, the negative pole piece and the separator in the electrode assembly of the lithium ion battery can be wound and then compacted.
  • FIG. 1 which is a schematic three-dimensional structure of an electrode assembly
  • the electrode assembly includes a negative pole piece, a positive pole piece and a separator, wherein the negative pole piece, the positive pole piece and the separator are stacked and wound around
  • the axis K is wound to form a winding structure.
  • the separator is an insulating film used to separate the negative pole piece and the positive pole piece to prevent the short circuit of the negative pole piece and the positive pole piece.
  • the winding structure of the electrode assembly is in the shape of a flat body , a schematic structural diagram of a cross-section of the electrode assembly along a direction perpendicular to the winding axis K can be shown in FIG. 2 .
  • the electrode assembly includes a flat region 100 and bending regions 200 located at both ends of the flat region 100 .
  • the flat region 100 refers to an area with a parallel structure in the winding structure, that is, the negative electrode piece 101, the positive electrode piece 102 and the separator 103 in the flat region 100 are substantially parallel to each other, that is, the electrode assembly is in the flat region.
  • the surfaces of each layer of negative pole piece 101 , positive pole piece 102 and separator 103 of 100 are all flat surfaces.
  • the bending area 200 refers to the area with a bending structure in the winding structure, that is, the negative electrode piece 101 , the positive electrode piece 102 and the separator 103 in the bending area 200 are all bent, that is, the electrode assembly is bent.
  • the surfaces of each layer of the negative pole piece 101, the positive pole piece 102 and the separator 103 in the area 200 are curved surfaces, and the bending area 200 has a bending direction L, which can be understood as the direction of the electrode assembly along the bending area.
  • the surface points in the direction of the flat area, eg, the bending direction L in the bending area 200 is along the winding direction of the wound structure.
  • the surface of the negative electrode pole piece 101 has a negative electrode active material layer composed of a negative electrode active material
  • the surface of the positive electrode pole piece 102 has a positive electrode active material layer composed of a positive electrode active material
  • the positive electrode active material can be lithium manganate, lithium cobaltate , lithium iron phosphate or lithium nickel cobalt manganate
  • the negative electrode active material can be graphite or silicon.
  • lithium ions are deintercalated from the positive electrode and inserted into the negative electrode, but some abnormal situations may occur, such as insufficient space for lithium ion insertion in the negative electrode, too much resistance for lithium ions to be inserted into the negative electrode, or lithium ions are deintercalated from the positive electrode too quickly.
  • the deintercalated lithium ions cannot be embedded in the negative electrode active material layer of the negative electrode pole piece in the same amount, and the lithium ions that cannot be embedded in the negative electrode pole piece can only get electrons on the surface of the negative electrode, thereby forming silver-white metallic lithium element, which is the phenomenon of lithium precipitation .
  • Lithium precipitation not only reduces the performance of lithium-ion batteries and greatly shortens the cycle life, but also limits the fast charge capacity of lithium-ion batteries.
  • the precipitated lithium metal is very active, and can react with the electrolyte at a lower temperature, resulting in a decrease in the starting temperature (Tonset) of the battery's self-generated heat and self-generated heat. The heat rate increases, which seriously endangers the safety of the battery.
  • Tonset starting temperature
  • the deintercalated lithium ions can form lithium crystals on the surface of the negative electrode, and the lithium crystals easily pierce the separator, resulting in the risk of short circuit between the adjacent positive and negative electrodes.
  • the cause of the lithium precipitation was caused by the shedding of the active material, mainly because the negative electrode active material was coated. Covered on the surface of the negative pole piece, the positive active material is coated on the surface of the positive pole piece, and the positive pole piece and the negative pole piece located in the turning area need to be bent, so it may cause their respective active materials to fall off, called In order to avoid the phenomenon of powder falling, especially the innermost pole piece in the bending area has the largest bending degree, which is more likely to cause the active material to fall off.
  • the lithium insertion site of the negative electrode active material layer of the negative pole piece may be less than the lithium ion that can be provided by the positive active material layer of the adjacent positive pole piece. Therefore, when the lithium battery is charged, the phenomenon of lithium precipitation is prone to occur.
  • the present application intends to provide an electrode assembly
  • the electrode assembly includes a negative pole piece, a positive pole piece and a separator, wherein the negative pole piece, the positive pole piece and the separator can be laminated around the winding axis to form a roll
  • the winding structure for example, the winding structure of the flat body, the negative pole piece, the positive pole piece and the separator can also be continuously folded in a zigzag shape after lamination, whether the electrode assembly is formed by winding or continuous in a zigzag shape.
  • the electrode assembly is formed by folding, and the electrode assembly includes a flat area and a bending area connecting both ends of the flat area. In order to reduce or avoid lithium precipitation, any adjacent positive electrode and negative electrode in the bending area are set.
  • a barrier layer in particular, a barrier layer is provided between the adjacent positive pole pieces and the negative pole pieces at the innermost side of the bending area, and the barrier layer is used to block at least the positive electrode active material layer from the positive electrode active material layer of the positive pole piece in the bending area.
  • a part of lithium ions, so that the ions blocked by the barrier layer cannot be embedded in the negative electrode active material layer of the negative electrode pole piece adjacent to the positive electrode pole piece in the bending area, so that the negative electrode active material layer of the negative electrode pole piece in the bending area is embedded.
  • the number of lithium ions that can be provided by the lithium site and the positive active material layer of the adjacent positive electrode sheet is basically the same, so the occurrence of lithium deposition can be reduced or avoided.
  • the electrode assembly includes a flat region and a bending region connecting both ends of the flat region.
  • the electrode assembly of this embodiment Taking the flat body winding structure as an example for description, for example, the structure of one of the bending regions C and the straight region P of the flat body winding structure can be as shown in FIG.
  • the electrode assembly includes a positive pole piece 1, a negative pole piece 2 and a separator 3 for separating the positive pole piece 1 and the negative pole piece 2 in its folded area C, wherein the separator 3 can be independent between the adjacent positive pole piece 1 and the negative pole piece 2, or can be coated on the surface of the positive pole piece 1 or the negative pole piece 2.
  • the separator 3 has electronic insulating properties and is used to isolate the adjacent positive pole pieces 1 and negative pole pieces 2 to prevent the adjacent positive pole pieces 1 and negative pole pieces 2 from being short-circuited.
  • the isolation film 3 has a large number of through-holes, which can ensure the free passage of electrolyte ions and have good permeability to lithium ions. Therefore, the isolation film 3 basically cannot block the passage of lithium ions.
  • the isolation film 3 includes a membrane base layer and a functional layer located on the surface of the membrane base layer.
  • the membrane base layer can be at least one of polypropylene, polyethylene, ethylene-propylene copolymer, polybutylene terephthalate, etc., and the functional layer It can be a mixture layer of ceramic oxide and binder.
  • the electrode assembly of the embodiment of the present application further has a barrier layer 4 in its bending region C, wherein at least a part of the barrier layer 4 is located between the adjacent positive pole pieces 1 and the negative pole pieces 2, and is used for blocking the movement of the positive pole piece from the positive pole piece. At least a part of the ions released from 1 are inserted into the negative pole piece 2 of the bending region C.
  • a barrier layer 4 is provided between the adjacent positive pole pieces 1 and the negative pole pieces 2.
  • the ions released from the positive active material layer of the positive pole piece 1 (for example, the positive active material layer of the bending region C) It is blocked by the barrier layer 4, so that the ions blocked by the barrier layer 4 cannot be embedded in the negative electrode active material layer of the negative electrode pole piece 2 in the bending region C, so that when the negative electrode active material falls off of the negative electrode pole piece 2, the occurrence of lithium precipitation is reduced, That is, although the negative electrode pole piece 2 is reduced due to the shedding of the negative electrode active material, the lithium intercalation position is reduced, but because the barrier layer 4 blocks at least a part of the lithium ions detached from the positive electrode pole piece 1 adjacent to the negative pole piece 2, it can reduce or even avoid lithium precipitation. happened.
  • the material of the barrier layer 4 may include inorganic oxides and/or high molecular polymers.
  • the inorganic oxide may be magnesium oxide (MgO), calcium oxide (CaO), boehmite, wollastonite, barium sulfate (BaSO4), calcium sulfate (CaSO4), calcium carbonate ( At least one of CaCO3), alumina (Al2O3) and silica (SiO2).
  • the high molecular polymer may be polypropylene (polypropylene), polyvinyl chloride (PVC), polyethylene (PE), epoxy resin, polyacrylate and polyurethane rubber at least one of them.
  • the barrier layer 4 may be adhesive tape or adhesive paper.
  • the adhesive tape includes an adhesive and a base material, wherein the material of the base material may include polyethylene and/or ethylene-vinyl acetate copolymer (Ethylene Vinyl Acetate Copolymer, EVA) and the like.
  • the material of the adhesive paper includes at least one of polyethylene phthalate, polyvinylidene fluoride, polyurethane, sodium polyacrylate, styrene-butadiene rubber, polyetherimide, carboxymethyl cellulose and acrylate.
  • a positive electrode sheet 1 and a negative electrode sheet 2 may be stacked and then rolled or folded, or at least one (for example, two or more) positive electrode sheet 1 And at least one (for example, two or more) negative pole pieces 2 are stacked and rolled or folded, and a bending area C is formed, when the electrode assembly has a multi-layer positive pole piece 1 and a multi-layer in the bending area C.
  • the bending area C includes a structure in which the positive pole piece 1 and the negative pole piece 2 are alternately distributed, and at least one adjacent layer of the positive pole piece 1 and the negative pole piece 2 includes a barrier layer 4 .
  • the positive pole piece 1 and the negative pole piece 2 adjacent to the bending area C refer to a layer of positive pole piece 1 and a layer of negative pole piece 2 adjacent to each other in the bending area C and there is no other layer of positive pole piece between them.
  • the bending area C (for example, the innermost and/or innermost part of the bending area C Outermost) also can exist the structure that there is no negative pole piece 2 between adjacent two layers of positive pole pieces 1, or, there is no structure of positive pole piece 1 between adjacent two layers of negative pole pieces 2, then this adjacent
  • the barrier layer 4 may not be provided between the two layers of positive electrode pole pieces 1 or the adjacent two layers of negative electrode pole pieces 2 , that is, the barrier layer 4 is arranged between the adjacent positive electrode pole pieces 1 and the negative electrode pole pieces 2 .
  • the innermost pole piece in the bending region C of the electrode assembly, is generally the most bent, that is, the active material of the innermost pole piece has the greatest probability of falling off or the active material falls off the most seriously.
  • the inner pole piece can be a positive pole piece 1 or a negative pole piece 2 .
  • the innermost pole piece is the negative pole piece 2
  • there is a barrier layer 4 between at least the innermost adjacent positive pole piece 1 and the negative pole piece 2 in the bending area C in order to reduce the occurrence of lithium precipitation as much as possible.
  • the lithium deposition phenomenon between the innermost adjacent positive electrode and negative electrode can be reduced, and the safety performance can be improved.
  • the utilization efficiency of the active material of the positive pole piece 1 can be improved.
  • the barrier layer 4 is located between the adjacent positive pole piece 1 and the negative pole piece 2, either the barrier layer 4 is independently located between the adjacent positive pole piece 1 and the negative pole piece 2, or it can be a barrier layer 4 Attached to any surface of the positive pole piece 1 , the negative pole piece 2 or the separator 3 .
  • the barrier layer 4 is independently located between the adjacent positive pole pieces 1 and the negative pole pieces 2, which means that the barrier layer 4 is separately laminated with the positive pole piece 1 and the negative pole piece 2, that is, there is no adhesion or
  • the coating relationship is beneficial to the installation of the barrier layer 4; and the attachment refers to adhesion, coating or spraying, and by attaching, the positional movement of the barrier layer 4 during the use of the battery cell can be reduced.
  • the barrier layer 4 is attached to one surface or both surfaces of the positive pole piece 1 , and/or the barrier layer 4 is attached to one surface or both surfaces of the negative pole piece 2 .
  • the barrier layer 4 is independent of between the adjacent positive electrode pieces 1 and the separator 3 in the bending region C, or the barrier layer 4 is independent of the adjacent negative electrodes in the bending region C Between the pole piece 2 and the isolation membrane 3 , or alternatively, the barrier layer 4 is attached to one surface or both surfaces of the isolation membrane 3 .
  • the barrier layer 4 is independent from between the adjacent positive pole pieces 1 and the separator 3 in the bending region C, or, the barrier layer 4 is independent from between the adjacent negative pole pieces 2 and the separator 3 in the bending region C, It means that the barrier layer 4 is separately laminated with the positive pole piece 1 , the negative pole piece 2 and the separator 3 , that is, there is no adhesion or coating relationship.
  • both ends of the barrier layer 4 extending along the bending direction L are located in the bending area C, that is, all the barrier layers 4 are located in the bending area C.
  • the electrode assembly further includes a straight area P connected to the bending area C, and the bending direction L refers to a direction along the curved surface of the bending area C and pointing to the straight area P, which is perpendicular to the bending direction
  • the direction of L refers to the direction perpendicular to the bending direction L.
  • one end of the barrier layer 4 extending along the bending direction L is located in the straight area P, and the other end is located in the bending area C.
  • the barrier layer 4 in order to block more lithium ions as much as possible, has a larger area in the bending region C as much as possible, for example, both ends of the barrier layer 4 extending along the bending direction L are Located in the flat region P, that is, the barrier layer 4 extends to the flat region P in addition to the bending region C.
  • both ends of the barrier layer 4 extending along the bending direction L are located at the junction of the bending area C and the straight area P, or both ends of the barrier layer 4 extending along the bending direction L Both are close to the junction of the bending area C and the straight area P.
  • the negative pole piece 2 in the innermost part has the largest curvature of the negative electrode active
  • the material shedding is the most serious, so no matter how the barrier layer 4 extends along the bending direction L, the barrier layer 4 blocks the lithium ions protruding from the positive pole piece 1 as far as possible from inserting into the part with the largest curvature in the negative pole piece 2, that is, the barrier layer 4 and the
  • the parts with the largest curvature in the negative pole piece 2 are arranged opposite to each other, and are used to cover the part with the largest curvature in the negative pole piece 2 . In this way, it is possible to prevent lithium ions or a small amount of lithium ions from being inserted into the portion of the negative pole piece 2 with the largest curvature, thereby reducing the occurrence of lithium deposition.
  • the part with the largest curvature of the negative pole piece 2 at the innermost part of the bending area C is a line (
  • the line may be a straight line), and the curvature of any point on the line is greater than the curvature of the curved surface of the innermost negative pole piece 2 of the bending region C on both sides of the point along the bending direction L.
  • the part with the largest curvature of the negative pole piece 2 at the innermost part of the bending area C is the negative pole piece 2 in the middle of the bending area C part.
  • FIG. 4 which is a schematic structural diagram of the distribution of the barrier layer after the bending area C of the electrode assembly according to another embodiment of the present application is flattened
  • the adjacent positive pole pieces 1 and negative pole pieces in the bending area C are shown in FIG. 4 .
  • 2 includes a plurality of discontinuous barrier layers 4, and the discontinuous plurality of barrier layers 4 are distributed along the bending direction L at intervals, so that part of the lithium ions are not blocked by the barrier layer 4, that is, part of the lithium ions are blocked from the adjacent two.
  • the negative electrode active material layer of the negative electrode pole piece 2 is inserted between the layers 4 .
  • a discontinuous plurality of barrier layers 4 are attached on the surface of the positive electrode sheet 1 . In this way, the passage of some lithium ions can be blocked, the occurrence of lithium precipitation can be reduced, and the energy density of the electrode assembly can be guaranteed.
  • FIG. 5 is a schematic structural diagram of another barrier layer distribution after the bending area of the electrode assembly according to another embodiment of the present application is flattened
  • the adjacent positive pole pieces 1 and negative electrodes in the bending area are A plurality of discontinuous barrier layers 4 are included between the pole pieces 2, and the discontinuous plurality of barrier layers 4 are distributed at intervals along the K direction perpendicular to the bending direction L, so that some lithium ions are not blocked by the barrier layers 4, that is, some lithium ions are not blocked by the barrier layers 4.
  • the ions pass between the two adjacent barrier layers 4 to be inserted into the negative electrode active material layer of the negative electrode sheet 2 .
  • the K direction perpendicular to the bending direction L may be the width direction of the positive pole piece 1 and the negative pole piece 2 .
  • the K direction perpendicular to the bending direction L is the direction of the winding axis of the wound structure.
  • FIG. 6 which is a schematic structural diagram of another barrier layer distribution after the bending region of the electrode assembly according to another embodiment of the application is flattened
  • the barrier layer 4 is attached to the surface of the positive electrode sheet 1 .
  • the barrier layer 4 has at least one through hole 41 , which is used for part of the lithium ions to be inserted into the negative electrode active material layer of the negative electrode pole piece 2 .
  • the porosity of the barrier layer 4 is smaller than that of the isolation film 3, so that the barrier layer 4 can more effectively block the passage of lithium ions.
  • porosity refers to the percentage of the pore volume in the bulk material to the total volume of the material in its natural state.
  • the test method for porosity is the true density test method.
  • the thickness of the barrier layer 4 is A micron
  • the porosity of the barrier layer 4 is B, where A and B satisfy the following relationship: 3.5 microns ⁇ A/B ⁇ 2000 microns, optionally 7 microns ⁇ A/B ⁇ 1000 microns.
  • A is too small, it means that the thickness of the barrier layer 4 is too small, and lithium crystals are likely to pierce the barrier layer 4, and even the isolation film 3, so that the barrier layer 4 loses the function of blocking lithium ions, and there may be a safety risk; That is to say, the porosity of the barrier layer 4 is too large.
  • A/B is less than 3.5
  • A/B is greater than 2000
  • A is large, that is, the thickness of the barrier layer 4 is too large
  • B is small, that is, the porosity of the barrier layer 4 is too small, which seriously affects the energy density of the battery cell.
  • the thickness of the barrier layer 4 is 2-200 micrometers (um), optionally, the thickness of the barrier layer 4 is 5-100 micrometers, and further optionally, the thickness of the barrier layer 4 is 5-50 micrometers.
  • the thickness of the barrier layer 4 is less than 2um, the thickness of the barrier layer 4 is too small.
  • the lithium precipitation is serious, the lithium crystallization will pierce the barrier layer 4, and even pierce the isolation film 3, so that the barrier layer 4 loses the ability to block lithium ions. , there is a security risk.
  • the thickness of the barrier layer 4 is greater than 500um, the thickness of the barrier layer 4 is relatively large, resulting in an excessively large gap between the adjacent positive electrode piece 1 and the negative electrode piece 2, and the barrier layer 4 occupies space, which may affect the energy of the electrode assembly Density, furthermore, the gap between adjacent two layers is too large, which may seriously affect the cycle performance.
  • the porosity of the barrier layer 4 is 10%-70%, optionally, the porosity of the barrier layer 4 is 20%-60%. In this way, both the safety of the electrode assembly and the energy density of the electrode assembly can be ensured, and a better balance can be achieved between safety performance and energy density.
  • the porosity when the porosity is less than 10%, most or all of the lithium ions will be blocked by the barrier layer 4 and cannot be embedded in the negative electrode plate 2, thus affecting the energy density of the electrode assembly; and when the porosity is greater than 70% At this time, most or almost all of the lithium ions will pass through the barrier layer 4, and there will be a risk of lithium precipitation, resulting in lithium crystals piercing the barrier layer 4, so that the barrier layer 4 loses the function of blocking lithium ions, and there is a safety risk.
  • the width direction of the positive pole piece 1 and the negative pole piece 2 is parallel to the winding axis direction, and the width direction of the positive pole piece 1 and the negative pole piece 2 is perpendicular to the bending direction L.
  • the directions are parallel; when the electrode assembly does not have a winding structure, the width direction of the positive pole piece 1 and the negative pole piece 2 is parallel to the direction perpendicular to the bending direction L, which is simple for the subsequent description.
  • the positive pole piece The width direction of 1 and the negative pole piece 2 , the direction perpendicular to the bending direction L, and the winding axis direction are collectively referred to as the K direction.
  • the structure of the negative electrode pole piece 2 can be shown in FIG. 7 , which is a schematic structural diagram of a negative electrode pole piece according to another embodiment of the application.
  • the negative electrode pole piece 2 includes a negative electrode main body portion 21 and extends outward from the negative electrode main body portion 21 along the K direction.
  • the negative electrode tab portion 22, at least part of the area along the K direction on the surface of the negative electrode body portion 21 is the negative electrode active material region 211, and the negative electrode active material region 211 is used to coat the negative electrode active material, and the negative electrode active material can be graphite or silicon.
  • the surface of the negative electrode main body part 21 is provided with the negative electrode active material region 211 , but the surface of the negative electrode tab part 22 and the root region of the negative electrode main body part 21 are also provided with negative electrode active material
  • the region 211 that is, a partial region of the negative electrode tab portion 22 is the negative electrode active material region 211 .
  • the negative electrode active material region 211 covers the entire surface of the negative electrode main body portion 21 along the direction K.
  • the positive active material may not cover the entire surface of the positive electrode sheet 1 , for example, as shown in FIG. 8 , which is a schematic structural diagram of a positive electrode sheet in another embodiment of the present application.
  • the positive electrode sheet 1 includes a positive electrode main body portion 11 and at least one positive electrode tab portion 12 extending to the outside of the positive electrode main body portion 11 along the K direction. At least part of the surface of the positive electrode main body portion 11 is a positive electrode active material region 111 .
  • the region 111 may be coated with a positive active material, for example, the positive active material may be a ternary material, lithium manganate or lithium iron phosphate.
  • the surface of the positive electrode body portion 11 further includes a first insulating layer coating region 112 adjacent to the positive electrode active material region 111 , and the first insulating layer coating region 112 is located in the positive electrode active material region 111 Adjacent to the side of the positive electrode tab portion 12, the first insulating layer coating region 112 is used for coating insulating material for insulating and isolating the positive electrode active material region 111 and the positive electrode tab portion 12. For example, as shown in FIG.
  • FIG. 9 it is 8 is a schematic diagram of the cross-sectional structure in the direction AA, the two surfaces of the current collector 10 of the positive electrode sheet 1 have positive active material regions 111, and the positive electrode tab portion 12 is a part of the current collector 10 of the positive electrode sheet 1, wherein the current collector
  • the material of 10 may be aluminum.
  • the positive electrode active material region 111 and the first insulating layer coating region 112 are distributed at both ends on the surface of the positive electrode main body portion 11 along the width direction of the positive electrode main body portion 11 (ie, the K direction), and the positive electrode tab portion 12 and the first An insulating layer coating region 112 belongs to the same end of the positive electrode body portion 11 .
  • the positive electrode active material region 111 and the first insulating layer coating region 112 are two substantially parallel regions on the surface of the positive electrode main body part 11 , and are located on the surface of the positive electrode main body part 11 along the K direction. There are two layers on the surface.
  • the first insulating layer coating region 112 may be located at the portion where the positive electrode body portion 11 and the positive electrode tab portion 12 are connected to each other, for example, the first insulating layer coating region 112 is located on the positive electrode body portion 11
  • the part on the surface of the positive electrode tab part 12 and interconnected with the positive electrode tab part 12 is used to separate the surface of the positive electrode tab part 12 and the positive electrode active material region 111 .
  • not only the first insulating layer coating region 112 is provided on the surface of the positive electrode body portion 11
  • the second insulating layer is provided on the root region of the positive electrode tab portion 12 close to the positive electrode body portion 11 .
  • the coating area 121 and the second insulating layer coating area 121 are used for coating insulating substances.
  • the surface of the first insulating layer coating region 112 is coated with an insulating substance, and the insulating substance includes an inorganic filler and an adhesive.
  • Inorganic fillers include one of boehmite, alumina, magnesia, titania, zirconia, silica, silicon carbide, boron carbide, calcium carbonate, aluminum silicate, calcium silicate, potassium titanate, barium sulfate or several.
  • the binder includes one or more of polyvinylidene fluoride, polyacrylonitrile, polyacrylic acid, polyacrylate, polyacrylic acid-acrylate, polyacrylonitrile-acrylic acid, and polyacrylonitrile-acrylate.
  • each positive electrode sheet 1 may include one or two or more than two positive electrode tab portions 12 , when the positive electrode electrode sheet 1 includes two or more positive electrode tab portions 12 , all the positive electrode tabs 12 are located on the same side of the positive electrode piece 1 along the K direction.
  • the negative active material region 211 of the negative pole piece 2 exceeds the positive active material of the adjacent positive pole piece 1 at both ends along the direction K.
  • the corresponding end of the region 111 in this way, the energy density of the electrode assembly can be guaranteed.
  • the two ends of the negative electrode active material region 211 along the direction K are the first end 23 and the second end 24 respectively, and the two ends of the positive electrode active material region 111 along the direction K are the third end 13 and the fourth end 14 respectively, wherein,
  • the first end 23 of the negative electrode active material region 211 and the third end 13 of the positive electrode active material region 111 are located on the same side of the electrode assembly along the direction K, and the first end 23 of the negative electrode active material region 211 extends beyond the positive electrode active material region along the direction K
  • the third end 13 of 111, the second end 24 of the negative electrode active material region 211 and the fourth end 14 of the positive electrode active material region 111 are located on the other side of the electrode assembly along the direction K, and the second end 24 of the negative electrode active material region 211 is along the direction K.
  • the direction K extends beyond the fourth end 14 of the positive electrode active material region 111 .
  • the size of the two ends of the negative electrode active material region 211 along the winding axis K beyond the corresponding end of the positive electrode active material region 111 may be the same or different, for example, the excess size ranges from 0.2 mm to 5 mm.
  • the barrier layer 4 is attached to the surface of the positive electrode active material region 111 , that is, the surface of the positive electrode active material layer.
  • the barrier layer 4 includes a fifth end 42 and a sixth end 43 along the direction perpendicular to the bending direction (ie, the direction K), and the fifth end 42 of the barrier layer 4 extends beyond the positive pole piece 1
  • the sixth end 43 of the positive electrode active material layer and/or the barrier layer 4 is beyond the positive electrode active material layer, that is, the fifth end 42 of the barrier layer 4 is beyond the third end 13 of the positive electrode active material region 111 along the direction K, and/or,
  • the sixth end 43 of the barrier layer 4 protrudes beyond the fourth end 14 of the positive electrode active material region 111 along the direction K, for example, the protruding size ranges from 0.2 mm to 5 mm. In this way, the passage of more lithium ions can be blocked, and the occurrence of lithium precipitation can be reduced.
  • the fifth end 42 and the sixth end 43 of the barrier layer 4 do not exceed the corresponding ends of the negative electrode active material layer of the negative electrode pole piece 2 , that is, the negative electrode active material region of the negative electrode pole piece 2
  • the first end 23 is beyond the fifth end 42 of the barrier layer 4
  • the second end 24 of the negative active material region of the negative electrode sheet 2 is beyond the sixth end 43 of the barrier layer 4 .
  • the portion of the negative pole piece 2 beyond the barrier layer 4 can be embedded with lithium ions, which can ensure the energy density of the electrode assembly.
  • the electrode assembly includes a negative pole piece 91 , a positive pole piece 92 , and a separator 93 , the first barrier layer 94, the second barrier layer 95 and the third barrier layer 96, wherein the separator 93 is located between the negative pole piece 91 and the positive pole piece 92, the separator 93 is two pieces, in the electrode assembly of FIG.
  • the winding structure of the electrode assembly includes a straight area 9A and a first bending area 9B1 and a second bending area 9B2 on both sides of the straight area 9A, wherein the straight area 9A is respectively connected to the first bending area 9B1 and the second bending area 9B2.
  • the division of the bending area 9B1 and the second bending area 9B2 is respectively divided by straight dashed lines.
  • the negative pole pieces 91 and the positive pole pieces 92 included in the first bending area 9B1 and the second bending area 9B2 of the electrode assembly are alternately stacked in turn, and there is a separator 93 between the adjacent negative pole pieces 91 and the positive pole pieces 92, wherein , the innermost pole pieces of the first bending area 9B1 and the second bending area 9B2 are both negative pole pieces 91, and the innermost positive pole pieces 92 of at least the innermost positive pole piece 92 of the first bending area 9B1 and the second bending area 9B2
  • the surface is provided with (eg, attached to) a barrier layer, for example, the inner surface of each positive electrode sheet 92 of the first and second bent regions 9B1 and 9B2 is provided with (eg, attached to) a barrier layer.
  • the inner surface of the positive pole piece 92 refers to the surface of the positive pole piece 92 facing the winding axis, or the surface facing the inside of the winding structure.
  • the first bending region 9B1 has multiple layers of pole pieces, such as three-layer pole pieces, and the innermost layer (which may also be referred to as the first layer) and the outermost layer (which may also be referred to as the third layer) of the first bending region 9B1 layer) of the pole pieces are the negative pole pieces 91, the pole piece between the innermost layer pole piece and the outermost pole piece (also can be referred to as the second layer pole piece) is the positive pole piece 92, the positive pole piece 92 is the innermost positive pole piece of the first bending region 9B1, and the first barrier layer 94 is attached to the inner surface of the positive pole piece 92 of the first bending region 9B1.
  • the second bending area 9B2 has multiple layers of pole pieces, such as five-layer pole pieces. In the direction from the inside to the outside of the winding structure, the negative pole pieces 91 and the positive pole pieces 92 of the second bending area 9B2 are alternately stacked in sequence.
  • the innermost pole piece of the two bending regions 9B2 is the negative pole piece 91 , and a barrier layer is attached to the inner surface of each positive pole piece 92 of the second bending region 9B2 .
  • the second bending region 9B2 includes first, second, third, fourth and fifth layers of pole pieces in turn, and the first, third and fifth layers of pole pieces are negative pole pieces 91,
  • the second and fourth layers of pole pieces are positive pole pieces 92, and a barrier layer is attached to the inner surface of each layer of positive pole pieces 92 in the second bending region 9B2.
  • the second barrier layer 95 is attached to the inner side surface of the second layer pole piece (which is the positive pole piece 92 ) of the second bending region 9B2.
  • the third barrier layer 96 is attached to the inner side surface of the fourth layer pole piece (which is the positive pole piece 92 ) of the second bending region 9B2.
  • the two ends of the first barrier layer 94 , the second barrier layer 95 and the third barrier layer 96 along the bending direction are respectively located at the junction of the bending area and the straight area,
  • the two ends of the first barrier layer 94 along the winding direction are located at the junction of the first bending region 9B1 and the straight region 9A, respectively
  • the two ends of the second barrier layer 95 and the third barrier layer 96 along the winding direction are respectively It is located at the junction of the second bending area 9B2 and the straight area 9A.
  • the functions, structures, and distribution of the first barrier layer 94 , the second barrier layer 95 , and the third barrier layer 96 may all refer to the relevant information about the barrier layers described in the foregoing embodiments of FIGS. 1 to 10 . The content will not be repeated here.
  • the electrode assembly includes a negative electrode piece 1001 , a positive electrode piece 1002 , and a separator 1003, the first barrier layer 1004, the second barrier layer 1005 and the third barrier layer 1006, wherein, the separator 1003 is located between the negative pole piece 1001 and the positive pole piece 1002, the negative pole piece 1001, the positive pole piece 1002 and the separator 1003 is stacked and wound around the winding axis to form a flat body-shaped winding structure.
  • the winding structure of the electrode assembly includes a flat region 10A and a first bending region 10B1 and a second bending region 10B2 located on both sides of the flat region 10A.
  • the electrode assembly of this embodiment is basically similar to the electrode assembly described in the embodiment corresponding to FIG. 11 , and the differences may be as follows.
  • the outer surfaces of at least the innermost positive pole pieces 1002 of the first bending area 10B1 and the second bending area 10B2 are provided with (eg, attached to) a barrier layer, for example, the first bending area 10B1 and the second bending area
  • the outer surface of each positive pole piece 1002 of 10B2 is provided with (eg, attached to) a barrier layer.
  • the outer surface of the positive pole piece 1002 refers to the surface of the positive pole piece 1002 facing away from the winding axis, or the surface facing away from the inside of the winding structure.
  • the first barrier layer 1004 is attached to the outer side surface of the positive electrode piece 1002 of the first bending region 10B1.
  • the second barrier layer 1005 is attached to the outer surface of the second layer pole piece (which is the positive pole piece 1002 ) of the second bending region 10B2.
  • the third barrier layer 1006 is attached to the outer surface of the fourth layer pole piece (which is the positive pole piece 1002 ) of the second bending region 10B2.
  • both ends of the first barrier layer 1004 along the winding direction are located at the junction of the first bending region 10B1 and the straight region 10A, respectively, and the second barrier layer 1005 and the third barrier layer 1006 are located along the winding direction. The two ends are respectively located at the junction of the second bending region 10B2 and the straight region 10A.
  • the first barrier layer 1004 for the functions, structures, and distribution methods of the first barrier layer 1004 , the second barrier layer 1005 and the third barrier layer 1006 , etc., you may also refer to the related content of the barrier layers described in the foregoing embodiments of FIGS. 1-10 . The content will not be repeated here.
  • the electrode assembly includes a negative pole piece 1101 , a positive pole piece 1102 , and a separator 1103, the first barrier layer 1104, the second barrier layer 1105, the third barrier layer 1106, the fourth barrier layer 1107 and the fifth barrier layer 1108, wherein the separator 1103 is located between the negative pole piece 1101 and the positive pole piece 1102,
  • the negative pole piece 1101 , the positive pole piece 1102 and the separator 1103 are stacked and wound around the winding axis to form a flat-shaped winding structure.
  • the winding structure of the electrode assembly includes a flat region 11A and a first bending region 11B1 and a second bending region 11B2 located on both sides of the flat region 11A.
  • the electrode assembly of this embodiment is basically similar to the electrode assembly described in the embodiment corresponding to FIG. 11 , and the differences may be as follows.
  • the inner surface of at least the innermost negative pole piece 1101 of the first bending area 11B1 and the second bending area 11B2 is provided with (eg, attaching) a barrier layer, for example, the first bending area 11B1 and the second bending area
  • the inner surface of each negative pole piece 1101 of 11B2 is provided with a barrier layer.
  • the inner surface of the negative pole piece 1101 refers to the surface of the negative pole piece 1101 facing the winding axis, or the surface facing the inside of the winding structure.
  • the first barrier layer 1104 is attached to the inner surface of the innermost pole piece (which is the negative pole piece 1101 ) of the first bending region 11B1
  • the second barrier layer 1105 is attached to the outermost pole piece (which is the negative pole piece 1101 ). is the inner surface of the negative pole piece 1101).
  • the third barrier layer 1106 is attached to the inner side surface of the first layer pole piece (which is the negative pole piece 1101 ) of the second bending region 11B2 .
  • the fourth barrier layer 1107 is attached to the inner side surface of the third layer pole piece (which is the negative pole piece 1101 ) of the second bending region 11B2.
  • the fifth barrier layer 1108 is attached to the inner surface of the fifth-layer pole piece (which is the negative pole piece 1101 ) of the second bending region 11B2 .
  • both ends of the first barrier layer 1104 and the second barrier layer 1105 along the winding direction are located at the junction of the first bending region 11B1 and the straight region 11A, respectively.
  • the third barrier layer 1106 and the fourth barrier layer Both ends of the 1107 and the fifth barrier layer 1108 along the winding direction are respectively located at the junction of the second bending region 11B2 and the straight region 11A.
  • the functions, structures and distribution methods of the first barrier layer 1104 , the second barrier layer 1105 , the third barrier layer 1106 , the fourth barrier layer 1107 , and the fifth barrier layer 1108 , etc. can refer to the aforementioned figures.
  • the related content of the barrier layer described in the embodiments 1-10 will not be repeated here.
  • the electrode assembly includes a negative pole piece 1201 , a positive pole piece 1202 , and a separator. 1203, the first barrier layer 1204, the second barrier layer 1205, the third barrier layer 1206, the fourth barrier layer 1207 and the fifth barrier layer 1208, wherein the separator 1203 is located between the negative pole piece 1201 and the positive pole piece 1202,
  • the negative pole piece 1201 , the positive pole piece 1202 and the separator 1203 are stacked and wound around the winding axis to form a flat-shaped winding structure.
  • the winding structure of the electrode assembly includes a flat region 12A and a first bending region 12B1 and a second bending region 12B2 located on both sides of the flat region 12A.
  • the electrode assembly of this embodiment is basically similar to the electrode assembly described in the embodiment corresponding to FIG. 11 , and the differences may be as follows.
  • the outer surfaces of at least the innermost negative pole pieces 1201 of the first bending region 12B1 and the second bending region 12B2 are provided with (eg, attached to) a barrier layer, for example, the first bending region 12B1 and the second bending region
  • the outer surface of each negative pole piece 1201 of 12B2 is provided with a barrier layer.
  • the outer surface of the negative pole piece 1201 refers to the surface of the negative pole piece 1201 facing away from the winding axis, or the surface facing away from the inside of the winding structure.
  • the first barrier layer 1204 is attached to the outer surface of the innermost pole piece (which is the negative pole piece 1201 ) of the first bending region 12B1, and the second barrier layer 1205 is attached to the outermost pole piece (which is the negative pole piece 1201 ). is the outer surface of the negative pole piece 1201).
  • the third barrier layer 1206 is attached to the outer surface of the first layer pole piece (which is the negative pole piece 1201 ) of the second bending region 12B2.
  • the fourth barrier layer 1207 is attached to the outer surface of the third layer pole piece (which is the negative pole piece 1201 ) of the second bending region 12B2.
  • the fifth barrier layer 1208 is attached to the outer surface of the fifth layer pole piece (which is the negative pole piece 1201 ) of the second bending region 12B2.
  • both ends of the first barrier layer 1204 and the second barrier layer 1205 along the winding direction are located at the junction of the first bending region 12B1 and the straight region 12A, respectively.
  • the third barrier layer 1206 and the fourth barrier layer Both ends of the 1207 and the fifth barrier layer 1208 along the winding direction are respectively located at the junction of the second bending region 12B2 and the straight region 12A.
  • the functions, structures and distribution methods of the first barrier layer 1204 , the second barrier layer 1205 , the third barrier layer 1206 , the fourth barrier layer 1207 , and the fifth barrier layer 1208 can all refer to the aforementioned figures.
  • the related content of the barrier layer described in the embodiments 1-10 will not be repeated here.
  • the electrode assembly includes a negative electrode piece 1301 , a positive electrode piece 1302 , and a separator. 1303 and a plurality of barrier layers 1304, wherein the separator 1303 is located between the negative pole piece 1301 and the positive pole piece 1302, the negative pole piece 1301, the positive pole piece 1302 and the separator 1303 are stacked and wound around the winding axis to form a flat body Shaped winding structure.
  • the winding structure of the electrode assembly includes a straight area 13A and a first bending area 13B1 and a second bending area 13B2 located on both sides of the straight area 13A.
  • the electrode assembly of this embodiment is basically similar to the electrode assembly described in the embodiment corresponding to FIG. 11 , and the differences may be as follows.
  • a barrier layer 1304 is attached to at least the inner side surfaces of the innermost isolation films 1303 of the first bending area 13B1 and the second bending area 13B2, for example, each layer of isolation films of the first bending area 13B1 and the second bending area 13B2
  • a barrier layer 1304 is attached to the inner surface of 1303 .
  • the inner side surface of the isolation film 1303 refers to the surface of the isolation film 1303 facing the winding axis, or the surface facing the inside of the winding structure.
  • both ends of each barrier layer 1304 of the first bending region 13B1 along the winding direction are respectively located at the junction of the first bending region 13B1 and the straight region 13A, and each of the second bending regions 13B2 Both ends of the barrier layer 1304 along the winding direction are respectively located at the junctions of the second bending region 12B2 and the straight region 12A.
  • each barrier layer 1304 for the function, structure and distribution mode of each barrier layer 1304 , reference may be made to the relevant content of the barrier layer described in the foregoing embodiments of FIGS. 1-10 , and details are not repeated here.
  • the electrode assembly includes a negative pole piece 1401 , a positive pole piece 1402 , and a separator. 1403 and a plurality of barrier layers 1404, wherein the separator 1403 is located between the negative pole piece 1401 and the positive pole piece 1402, the negative pole piece 1401, the positive pole piece 1402 and the separator 1403 are stacked and wound around the winding axis to form a flat body Shaped winding structure.
  • the winding structure of the electrode assembly includes a flat region 14A and a first bending region 14B1 and a second bending region 14B2 located on both sides of the flat region 14A.
  • the electrode assembly of this embodiment is basically similar to the electrode assembly described in the embodiment corresponding to FIG. 11 , and the differences may be as follows.
  • a barrier layer 1404 is attached to the outer surface of at least the innermost isolation film 1403 of the first bending region 14B1 and the second bending region 14B2, for example, each layer of isolation of the first bending region 14B1 and the second bending region 14B2
  • a barrier layer 1404 is attached to the outside surface of the membrane 1403 .
  • the outer surface of the isolation film 1403 refers to the surface of the isolation film 1403 facing away from the winding axis, or the surface facing away from the inside of the winding structure.
  • both ends of each barrier layer 1404 of the first bending region 14B1 along the winding direction are respectively located at the junction of the first bending region 14B1 and the straight region 14A, and each of the second bending regions 14B2 Two ends of the barrier layer 1404 along the winding direction are respectively located at the junctions of the second bending region 12B2 and the straight region 12A.
  • each barrier layer 1404 for the function, structure and distribution mode of each barrier layer 1404 , reference may be made to the relevant content of the barrier layer described in the foregoing embodiments of FIGS. 1-10 , which will not be repeated here.
  • the electrode assembly includes a negative pole piece 1501 , a positive pole piece 1502 , and a separator. 1503 and a plurality of barrier layers 1504, wherein, the separator 1503 is located between the negative pole piece 1501 and the positive pole piece 1502, the negative pole piece 1501, the positive pole piece 1502 and the separator 1503 are stacked and wound around the winding axis to form a flat body Shaped winding structure.
  • the winding structure of the electrode assembly includes a flat region 15A and a first bending region 15B1 and a second bending region 15B2 located on both sides of the flat region 15A.
  • the negative pole pieces 1501 and the positive pole pieces 1502 included in the first bending area 15B1 and the second bending area 15B2 of the electrode assembly are alternately stacked in sequence, and any adjacent negative electrodes in the first bending area 15B1 and the second bending area 15B2
  • the inner and outer surfaces of at least the innermost positive pole piece 1502 in the bending region 15B2 are provided with a barrier layer 1504, for example, the inner side of each layer of the positive pole piece 1502 in the first bending region 15B1 and the second bending region 15B2 Both the surface and the outer surface are provided with a barrier layer 1504 .
  • the inner surface of the positive pole piece 1502 refers to the surface of the positive pole piece 1502 facing the winding axis, or the surface facing the inside of the winding structure
  • the outer surface of the positive pole piece 1502 refers to the positive pole piece 1502 facing away from the winding The surface around the axis, or the surface facing away from the inside of the wound structure.
  • the first bending region 15B1 has multiple layers of pole pieces, such as three-layer pole pieces, and the innermost layer (which may also be referred to as the first layer) and the outermost layer (which may also be referred to as the third layer) of the pole pieces are the negative pole pieces 1501, the pole piece between the innermost pole piece and the outermost pole piece of the first bending area 15B1 (also known as the second layer pole piece) is the positive pole piece.
  • the tab 1502, the inner and outer surfaces of the positive pole tab 1502 of the first bend region 15B1 are provided with (eg, attached to) a barrier layer 1504.
  • the second bending area 15B2 has multiple layers of pole pieces, such as five-layer pole pieces. Along the direction from the inside to the outside of the winding structure, the negative pole pieces 1501 and the positive pole pieces 1502 of the second bending area 15B2 are alternately stacked in sequence.
  • the innermost pole piece of the two bending regions 15B2 is the negative pole piece 1501, and the inner and outer surfaces of each positive pole piece 1502 of the second bending region 15B2 are provided with (eg, attached to) a barrier layer 1504.
  • the second bending region 15B2 includes first, second, third, fourth and fifth layers of pole pieces in sequence, and the first, third and fifth layers of pole pieces are negative pole pieces 1501,
  • the second and fourth-layer pole pieces are positive pole pieces 1502, and barrier layers 1504 are provided on the inner and outer surfaces of the second and fourth-layer pole pieces in the second bending region 15B2.
  • both ends of each barrier layer 1504 along the bending direction are located at the junction of the bending area and the straight area, respectively, for example, each barrier of the first bending area 15B1
  • Both ends of the layer 1504 along the winding direction are respectively located at the junction of the first bending area 15B1 and the straight area 15A
  • both ends of each barrier layer 1504 of the second bending area 15B2 along the winding direction are respectively located at the second bending area.
  • each barrier layer 1504 for the function, structure, and distribution of each barrier layer 1504, reference may be made to the barrier layer described in the foregoing embodiments in FIGS. 1-10, and details are not repeated here.
  • the electrode assembly includes a negative electrode piece 1601 , a positive electrode piece 1602 , and a separator 1603 , the first barrier layer 1604, the second barrier layer 1605 and the third barrier layer 1606, wherein the separator 1603 is located between the negative electrode piece 1601 and the positive electrode piece 1602, the negative electrode piece 1601, the positive electrode piece 1602 and the separator 1603 After stacking, the winding structure is wound around the winding axis into a flat body shape.
  • the winding structure of the electrode assembly includes a first flat area 16A1, a second flat area 16A2, a first bending area 16B1 and a second bending area 16B2, and the first flat area 16A1 and the second flat area
  • the straight areas 16A2 are oppositely arranged
  • the first bending area 16B1 and the second bending area 16B2 are oppositely arranged
  • both ends of the first bending area 16B1 are respectively connected to the same side ends of the first straight area 16A1 and the second straight area 16A2
  • two ends of the second bending area 16B2 are respectively connected to the other same side ends of the first straight area 16A1 and the second straight area 16A2.
  • the negative pole pieces 1601 and the positive pole pieces 1602 included in the first bending area 16B1 and the second bending area 16B2 of the electrode assembly are alternately stacked in turn, and there is a separator 1603 between the adjacent negative pole pieces 1601 and the positive pole pieces 1602, wherein , the innermost pole pieces of the first bending area 16B1 and the second bending area 16B2 are both negative pole pieces 1601, and at least the innermost positive pole pieces 1602 of the first bending area 16B1 and the second bending area 16B2 are inside
  • the surface is provided with (eg, attached to) a barrier layer, eg, the inner surface of each positive electrode piece 1602 of the first bending region 16B1 and the second bending region 16B2 is provided with (eg, attached to) a barrier layer.
  • the inner surface of the positive pole piece 1602 refers to the surface of the positive pole piece 1602 facing the winding axis, or the surface facing the inside of the winding structure.
  • the first bending region 16B1 has multiple layers of pole pieces, such as three-layer pole pieces, and the innermost layer (which may also be referred to as the first layer) and the outermost layer (which may also be referred to as the third layer) of the pole pieces are all negative pole pieces 1601, the pole piece between the innermost pole piece and the outermost pole piece (also known as the second layer pole piece) is the positive pole piece 1602, the first barrier layer 1604 is attached to the inner side surface of the positive pole piece 1602 of the first bending region 16B1.
  • the innermost layer which may also be referred to as the first layer
  • the outermost layer which may also be referred to as the third layer
  • the pole pieces are all negative pole pieces 1601
  • the pole piece between the innermost pole piece and the outermost pole piece also known as the second layer pole piece
  • the first barrier layer 1604 is attached to the inner side surface of the positive pole piece 1602 of the first bending region 16B1.
  • the second bending area 16B2 has multiple layers of pole pieces, such as five-layer pole pieces.
  • the negative pole pieces 1601 and the positive pole pieces 1602 of the second bending area 16B2 are alternately stacked in sequence.
  • the innermost pole piece of the second bending area 16B2 is the negative pole piece 1601, and a barrier layer is attached to the inner surface of each positive pole piece 1602 of the second bending area 16B2.
  • the second bending region 16B2 includes first, second, third, fourth and fifth layers of pole pieces in sequence, and the first, third and fifth layers of pole pieces are negative pole pieces 1601,
  • the second and fourth layers of pole pieces are the positive pole pieces 1602
  • the second barrier layer 1605 is attached to the innermost adjacent negative pole pieces 1601 and the inside of the positive pole pieces 1602 of the positive pole pieces 1602 in the second bending region 16B2
  • the second barrier layer 1605 is attached to the inner side surface of the second layer pole piece (which is the positive pole piece 1602 ) of the second bending region 16B2.
  • the third barrier layer 1606 is attached to the inner side surface of the fourth layer pole piece (which is the positive pole piece 1602 ) of the second bending region 16B2.
  • the first barrier layer 1604 includes a first end and a second end along the bending direction (ie, along the winding direction).
  • the first end of the first barrier layer 1604 is located in the first bending region 16B1, and the first barrier The second end of the layer 1604 is located in the first flat region 16A1.
  • the second barrier layer 1605 includes a first end and a second end along the bending direction (ie, along the winding direction), the first end of the second barrier layer 1605 is located in the second bending region 16B2, and the second The ends are located in the second flat region 16A2.
  • the third barrier layer 1606 includes a first end and a second end along the bending direction (ie, along the winding direction), the first end of the third barrier layer 1606 is located in the second bending region 16B2, and the second The ends are located in the second flat region 16A2. In another embodiment of the present application, the first end of the third barrier layer 1606 is located in the second bending region 16B2, and the second end of the third barrier layer 1606 may be located in the first straight region 16A1.
  • the functions, structures and distribution methods of the first barrier layer 1604 , the second barrier layer 1605 , and the third barrier layer 1606 may all refer to the related content of the barrier layers described in the foregoing embodiments of FIGS. 1-10 . The content will not be repeated here.
  • the electrode assembly includes a negative pole piece 1701 , a positive pole piece 1702 , and a separator 1703 , the first barrier layer 1704, the second barrier layer 1705 and the third barrier layer 1706, wherein the separator 1703 is located between the negative electrode piece 1701 and the positive electrode piece 1702, the negative electrode piece 1701, the positive electrode piece 1702 and the separator 1703
  • the winding structure is wound around the winding axis into a flat body shape.
  • the winding structure of the electrode assembly includes a first flat area 17A1, a second flat area 17A2, a first bending area 17B1 and a second bending area 17B2, and the first flat area 17A1 and the second flat area
  • the straight areas 17A2 are oppositely arranged
  • the first bending area 17B1 and the second bending area 17B2 are oppositely arranged
  • both ends of the first bending area 17B1 are respectively connected to the same side ends of the first straight area 17A1 and the second straight area 17A2
  • the two ends of the second bending area 17B2 are respectively connected to the other same side ends of the first straight area 17A1 and the second straight area 17A2.
  • the negative pole pieces 1701 and the positive pole pieces 1702 included in the first bending area 17B1 and the second bending area 17B2 of the electrode assembly are alternately stacked in turn, and there is a separator 1703 between the adjacent negative pole pieces 1701 and the positive pole pieces 1702, wherein , the innermost pole pieces of the first bending area 17B1 and the second bending area 17B2 are both negative pole pieces 1701, and the innermost positive pole pieces 1702 of at least the innermost positive pole piece 1702 of the first bending area 17B1 and the second bending area 17B2
  • the surface is provided with (eg, attached to) a barrier layer, eg, the inner surface of each positive electrode piece 1702 of the first bending region 17B1 and the second bending region 17B2 is provided with (eg, attached to) a barrier layer.
  • the inner surface of the positive pole piece 1702 refers to the surface of the positive pole piece 1702 facing the winding axis, or the surface facing the inside of the winding structure.
  • the first bending region 17B1 has multiple layers of pole pieces, such as three-layer pole pieces, and the innermost layer (which may also be referred to as the first layer) and the outermost layer (which may also be referred to as the third layer) of the first bending region 17B1 layer) of the pole pieces are negative pole pieces 1701, the pole piece between the innermost pole piece and the outermost pole piece (also known as the second layer pole piece) is the positive pole piece 1702, the first barrier layer 1704 is attached to the inner side surface of the positive pole piece 1702 of the first bending region 17B1.
  • the second bending area 17B2 has multiple layers of pole pieces, such as five-layer pole pieces. Along the direction from the inside to the outside of the winding structure, the negative pole pieces 1701 and the positive pole pieces 1702 of the second bending area 17B2 are alternately stacked in sequence. The innermost pole piece of the two bending regions 17B2 is the negative pole piece 1701 , and a barrier layer is attached to the inner surface of each positive pole piece 1702 of the second bending region 17B2 .
  • the second bending region 17B2 includes first, second, third, fourth and fifth layers of pole pieces in sequence, and the first, third and fifth layers of pole pieces are negative pole pieces 1701,
  • the second and fourth layers of pole pieces are the positive pole pieces 1702
  • the second barrier layer 1705 is attached to the innermost adjacent negative pole pieces 1701 and the inside of the positive pole pieces 1702 of the positive pole pieces 1702 in the second bending region 17B2
  • the second barrier layer 1705 is attached to the inner side surface of the second layer pole piece (which is the positive pole piece 1702 ) of the second bending region 17B2.
  • the third barrier layer 1706 is attached to the inner side surface of the fourth layer pole piece (which is the positive pole piece 1702 ) of the second bending region 17B2.
  • the first barrier layer 1704 includes a first end and a second end along the bending direction (ie, along the winding direction), and both the first end and the second end of the first barrier layer 1704 are located in the first bending region 17B1.
  • the second barrier layer 1705 includes a first end and a second end along the bending direction (ie, along the winding direction), and the first end of the second barrier layer 1705 is located at the junction of the second bending area 17B2 and the first straight area 17A1 , the second end of the second barrier layer 1705 is located at the junction of the second bending region 17B2 and the second straight region 17A2 .
  • the third barrier layer 1706 includes a first end and a second end along the bending direction (ie, along the winding direction), and both the first end and the second end of the third barrier layer 1706 are located in the second bending region 17B2 .
  • the curvature of each layer of pole pieces decreases sequentially, that is, the degree of bending decreases
  • the circumferential angle covered by each barrier layer in the second bending region 17B2 along the winding direction can be sequentially reduced.
  • the circumferential angle covered by the folding region 17B2 along the winding direction is smaller than the circumferential angle covered by the second barrier layer 1705 in the second folding region 17B2, for example, the circumference covered by the third barrier layer 1706 in the second folding region 17B2 along the winding direction
  • the angle is 90°
  • the circumferential angle covered by the second barrier layer 1705 in the second bending region 17B2 along the winding direction is 180°.
  • the functions, structures, and distribution methods of the first barrier layer 1704 , the second barrier layer 1705 , and the third barrier layer 1706 may all refer to the related content of the barrier layers described in the foregoing embodiments of FIGS. 1-10 . The content will not be repeated here.
  • FIG. 20 it is a schematic structural diagram of a battery cell according to another embodiment of the present application.
  • the battery cell includes a casing 181 and one or more electrode assemblies 182 accommodated in the casing 181.
  • the casing 181 includes a casing 1811 and a cover plate 1812.
  • the casing 1811 has an accommodating cavity, and the casing 1811 has an opening, that is, the plane There is no casing wall, so that the casing 1811 communicates with the inside and the outside, so that the electrode assembly 182 can be accommodated in the accommodating cavity of the casing 1811.
  • the cover plate 1812 and the casing 1811 are combined with the opening of the casing 1811 to form a hollow cavity.
  • the electrode assembly After 182 is accommodated in the casing 181, the casing 181 is filled with electrolyte and sealed.
  • the casing 1811 is determined according to the combined shape of one or more electrode assemblies 182 .
  • the casing 1811 may be a hollow cuboid, a hollow square, or a hollow cylinder.
  • one of the planes of the casing 1811 is an open surface, that is, the plane does not have a casing wall so that the casing 1811 communicates with the inside and the outside;
  • one of the circular side surfaces of the housing 1811 is an open surface, that is, the circular side surface does not have a housing wall so that the housing 1811 communicates with the inside and the outside.
  • the housing 1811 may be made of conductive metal material or plastic, and optionally, the housing 1811 may be made of aluminum or aluminum alloy.
  • the battery module 19 includes a plurality of interconnected battery cells 191 , wherein the plurality of battery cells 191 can be connected in series Either in parallel or in a mixed connection.
  • a mixed connection means that the connection includes both series and parallel connections.
  • the structure of the battery cell 191 can refer to the battery cell described in the embodiment corresponding to FIG. 20 , and details are not repeated here.
  • the battery includes a plurality of battery modules 19 and a box body
  • the box body includes a lower box body 20 and an upper box body 30, and a plurality of battery modules
  • the groups 19 can be connected in series, in parallel or in a mixed connection.
  • the lower case 20 has an accommodating cavity
  • the lower case 20 has an opening, so that the connected battery modules 19 can be accommodated in the accommodating cavity of the lower case 20.
  • the upper case 30 and the lower case 20 are combined at the opening of the lower case 20 to form a hollow cavity, and the upper case 30 and the lower case 20 are combined and sealed.
  • a battery can supply power to an electrical device alone, and the battery can be referred to as a battery pack, for example, used to power a car.
  • a plurality of batteries are connected to each other and then combined into a battery pack for supplying power to the electrical device.
  • the battery pack can also be accommodated in a box and packaged.
  • the following embodiments are described by taking the electric device including a battery as an example.
  • An embodiment of the present application also provides an electrical device, for example, the electrical device may be a car, such as a new energy vehicle, and the electrical device includes the battery described in the foregoing embodiment, wherein the battery used by the electrical device may be The battery described in the embodiment corresponding to FIG. 22 will not be repeated here.
  • the electrical device can be a car
  • the car can be a fuel car, a gas car or a new energy car
  • the new energy car can be Pure electric vehicles, hybrid vehicles or extended-range vehicles, etc.
  • the car includes a battery 2101 , a controller 2102 and a motor 2103 .
  • the battery 2101 is used for supplying power to the controller 2102 and the motor 2103 as the operating power and driving power of the car.
  • the battery 2101 is used for starting, navigating and running the car.
  • the battery 2101 supplies power to the controller 2102
  • the controller 2102 controls the battery 2101 to supply power to the motor 2103
  • the motor 2103 receives and uses the power of the battery 2101 as a driving power source for the car, instead or partially replacing fuel or natural gas to provide driving power for the car.
  • FIG. 24 is a schematic flowchart of a method for manufacturing an electrode assembly according to another embodiment of the present application, the method for manufacturing an electrode assembly includes the following contents.
  • Step 221 providing a positive pole piece, a negative pole piece and a barrier layer.
  • Step 222 winding or stacking the positive electrode and the negative electrode to form a bending area.
  • barrier layer in the bending region, wherein at least a part of the barrier layer is located between adjacent positive electrode and negative electrode pieces, and is used to prevent at least a part of ions protruding from the positive electrode piece from inserting into the bending region of the negative electrode electrode.
  • a separator for separating adjacent positive electrode and negative electrode sheets is also provided, and the separator, positive electrode sheet and negative electrode sheet are wound or laminated together.
  • the barrier layer is placed on one or both surfaces of the positive or negative electrode sheet before the separator, positive electrode sheet and negative electrode sheet are wound or laminated together.
  • the barrier layer is affixed or coated on one or both surfaces of the positive electrode or negative electrode.
  • the electrode assembly manufacturing equipment includes: a first providing device 231 , a second providing device 232 , a third providing device 233 , and an assembly device 234.
  • the first providing device 231 is used to provide a positive pole piece.
  • the second providing device 232 is used to provide a negative pole piece.
  • the third providing means 233 is used for providing the barrier layer.
  • the assembly device 234 is used for winding or stacking the positive electrode and the negative electrode to form a bending area.
  • barrier layer in the bending region, wherein at least a part of the barrier layer is located between the adjacent positive electrode and negative electrode, and is used to prevent at least a part of the ions protruding from the positive electrode from inserting into the bending region of the negative electrode.
  • the manufacturing equipment of the electrode assembly further includes a fourth providing device 235 for providing a separator for separating adjacent positive electrode and negative electrode sheets, and the assembling device 234 is used for connecting the positive electrode
  • the pole piece, the negative pole piece and the separator are wound or laminated to form a bending area.
  • a barrier layer is provided between the adjacent positive electrode and negative electrode pieces included in the electrode assembly of the battery cell.
  • layer blocking so that the ions blocked by the barrier layer cannot be embedded in the negative electrode active material layer of the negative electrode plate adjacent to the positive electrode plate in the bending area, so that when the negative electrode active material falls off, the occurrence of lithium precipitation is reduced, Improve the safety risk of battery cells and improve the service life of battery cells.

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Abstract

本申请的实施例公开一种电极组件、电池单体、电池及制造电极组件的方法和装置，该电极组件包括：正极极片和负极极片，正极极片和负极极片经过卷绕或者层叠后形成弯折区；弯折区具有阻挡层，其中，至少一部分阻挡层位于相邻正极极片和负极极片之间，用于阻挡从正极极片脱出的至少一部分离子嵌入弯折区的负极极片。根据上述描述的技术方案，在弯折区相邻的正极极片和负极极片之间设置阻挡层，可以阻挡正极活性物质层脱出的离子至少一部分嵌入与正极极片相邻的负极极片在弯折区的负极活性物质层，降低析锂的发生，提高电池单体的安全性能，提高电池单体使用寿命。

Description

电极组件、电池单体、电池及制造电极组件的方法和装置 技术领域
本申请涉及电池领域，尤其涉及一种电极组件、电池单体、电池及制造电极组件的方法和装置。
背景技术
可再充电电池，可以称为二次电池，是指在电池放电后可通过充电的方式使活性物质激活而继续使用的电池。可再充电电池广泛用于电子设备，例如手机、笔记本电脑、电瓶车、电动汽车、电动飞机、电动轮船、电动玩具汽车、电动玩具轮船、电动玩具飞机和电动工具等等。
可再充电电池可以包括镉镍电池、氢镍电池、锂离子电池和二次碱性锌锰电池等。
目前，汽车使用较多的电池一般是锂离子电池，锂离子电池作为一种可再充电电池，具有体积小、能量密度高、功率密度高、循环使用次数多和存储时间长等优点。
可再充电电池包括电极组件和电解质溶液，电极组件包括正极极片、负极极片和位于正极极片和负极极片之间的隔离膜。正极极片也可以称为阴极极片，正极极片的两个表面均具有正极活性物质层，例如，正极活性物质层的正极活性物质可为锰酸锂、钴酸锂、磷酸铁锂或者镍钴锰酸锂；负极极片也可以称为阳极极片，负极极片的两个表面均具有负极活性物质层，例如，负极活性物质层的负极活性物质可以是石墨或硅。
析锂是锂电池一种常见的异常现象，会影响锂离子的充电效率以及能量密度，析锂严重时还可以形成锂结晶，而锂结晶可以刺穿隔离膜从而导致内短路热失控，严重危害电池的安全。
因此，如何降低或避免析锂，提高电池安全，成为业内的一个难题。
发明内容
本申请的多个方面提供一种电极组件、电池单体、电池及制造电极组件的方法和装置，克服了上述问题或者至少部分地解决了上述问题。
本申请的第一方面提供一种电极组件，其中，包括：正极极片和负极极片，正极极片和负极极片经过卷绕或者层叠后形成弯折区；
弯折区具有阻挡层，其中，至少一部分阻挡层位于相邻正极极片和负极极片之间，用于阻挡从正极极片脱出的至少一部分离子嵌入弯折区的负极极片。通过在相邻的正极极片和负极极片之间设置阻挡层，在充电时，弯折区的正极极片的正极活性物质层脱出的离子至少一部分被阻挡层阻挡，使得被阻挡层阻挡的离子不能嵌入与正极极片相邻的负极极片在弯折区的负极活性物质层，使得当负极极片发生负极活性物质脱落时，降低析锂的发生，提高电池单体的安全性能，提高电池单体使用寿命。
在一些实施例中，电极组件还包括用于隔离相邻的正极极片和负极极片的隔离膜，正极极片的一个表面或两个表面附接阻挡层，和/或，负极极片的一个表面或两个表面附接阻挡层，和/或，隔离膜的一个表面或两个表面附接阻挡层。这样，可以减少阻挡层在电极组件使用过程中的位置移动。
在一些实施例中，电极组件还包括用于隔离相邻的正极极片和负极极片的隔离膜，阻挡层独立于弯折区相邻的正极极片和隔离膜之间，或者，阻挡层独立于弯折区相邻的负极极片和隔离膜之间。这样，可以便于阻挡层的安装。
在一些实施例中，阻挡层的孔隙率小于隔离膜的孔隙率。这样，阻挡层可以更有效地阻挡锂离子的通过。
在一些实施例中，电极组件包括一个正极极片和一个负极极片，一个正极极片和一个负极极片压实后经过卷绕后形成一个卷绕结构，其中，弯折区内至少最内侧的相邻正极极片和负极极片之间具有阻挡层。这样，可以减少最内侧的相邻正极极片和负极极片之间的析锂现象，提高安全性能。
在一些实施例中，弯折区最内侧的极片为负极极片。这样，可以提高正极极片的活性物质的利用效率。
在一些实施例中，阻挡层为非连续的多个，非连续的多个阻挡层沿弯折方向间隔分布，或者非连续的多个阻挡层沿垂直于弯折方向的方向间隔分布。这样，既可以阻挡部分锂离子的通过，减少析锂现象的发生，又可以保证电极组件的能量密度。
在一些实施例中，阻挡层的厚度为2-200微米；或5-100微米。这样，既可以保证电极组件的安全又可以保证电极组件的能量密度。
在一些实施例中，阻挡层具有至少一个通孔。
在一些实施例中，阻挡层的孔隙率为10％-70％；或20％-60％。这样，既可以保证电极组件的安全又可以保证电极组件的能量密度。
在一些实施例中，阻挡层的厚度为A微米，阻挡层的孔隙率为B，其中，A和B满 足以下关系式：3.5微米≤A/B≤2000微米；或7微米≤A/B≤1000微米。这样，既可以保证电极组件的安全又可以保证电极组件的能量密度。
在一些实施例中，负极极片的负极活性物质层沿垂直于弯折方向的两端均超出正极极片的正极活性物质层的对应端。这样，可以保证电极组件的能量密度。
在一些实施例中，阻挡层沿垂直于弯折方向包括两端，阻挡层的其中一端或两端超出正极极片的正极活性物质层。这样，可以阻挡较多锂离子的通过，减少析锂现象的发生。
在一些实施例中，阻挡层沿垂直于弯折方向包括两端，负极极片的负极活性物质层超出阻挡层的其中一端或两端。这样，既可以阻挡部分锂离子的通过，减少析锂的发生，又可以保证电极组件的能量密度。
在一些实施例中，阻挡层与负极极片的曲率最大的部位相对设置。这样，可以使得曲率最大的部位不嵌入锂离子或者嵌入少部分锂离子，从而减少析锂现象的发生。
在一些实施例中，阻挡层包括如下至少一种：无机氧化物、粘结剂和胶带。
在一些实施例中，阻挡层沿弯折方向延伸的两端均位于弯折区。这样，可以阻挡较多锂离子的通过，减少析锂现象的发生。
在一些实施例中，电极组件具有与弯折区连接的平直区；
阻挡层沿弯折方向延伸的一端位于平直区，另一端位于弯折区；或者，阻挡层沿弯折方向延伸的两端均位于平直区。
本申请的第二方面提供一种电池单体，其中，包括：壳体、盖板和至少一个上述实施例的电极组件，其中，
壳体具有容纳腔和开口，电极组件容纳于容纳腔中；
盖板用于封闭壳体的开口。
本申请的第三方面提供一种电池，其中，包括箱体和至少一个的电池单体，电池单体收容于箱体内。
本申请的第四方面提供一种电极组件的制造方法，其中，包括：
提供正极极片、负极极片以及阻挡层；
将正极极片和负极极片经过卷绕或者层叠，并形成弯折区，其中，弯折区中具有阻挡层，其中，至少一部分阻挡层位于相邻正极极片和负极极片之间，用于阻挡从正极极片脱出的至少一部分离子嵌入弯折区的负极极片。
在一些实施例中，提供用于隔开相邻正极极片和负极极片的隔离膜，将隔离膜、正极极片和负极极片一起卷绕或层叠。
在一些实施例中，在将隔离膜、正极极片和负极极片一起卷绕或层叠之前，方法还包括：将阻挡层置于正极极片或负极极片的一个或两个表面上。
在一些实施例中，将阻挡层置于正极极片或负极极片的一个或两个表面上具体包括：将阻挡层粘贴或涂覆于正极极片或负极极片的一个或两个表面上。
本申请的第五方面提供一种电极组件的制造设备，其中，包括：
第一提供装置，用于提供正极极片；
第二提供装置，用于提供负极极片；
第三提供装置，用于提供阻挡层；
组装装置，用于将正极极片和负极极片卷绕或者层叠，并形成弯折区；
其中，弯折区中具有阻挡层，其中，至少一部分阻挡层位于相邻正极极片和负极极片之间，用于阻挡从正极极片脱出的至少一部分离子嵌入弯折区的负极极片。
在一些实施例中，电极组件的制造设备还包括第四提供装置，用于提供用于隔开相邻正极极片和负极极片的隔离膜，组装装置还用于将正极极片、负极极片以及隔离膜经过卷绕或者层叠后形成弯折区。
在一些实施例中，第三提供装置为两个，两个第三提供装置用于分别提供阻挡层，并将阻挡层粘贴或涂覆于正极极片或负极极片的两个表面。
本申请的第六方面提供一种用电装置，其中，用电装置被配置为接收从的电池提供的电力。
上述说明仅是本申请实施例技术方案的概述，为了能够更清楚了解本申请实施例的技术手段，而可依照说明书的内容予以实施，并且为了让本申请实施例的上述和其它目的、特征和优点能够更明显易懂，以下特举本申请的具体实施方式。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对实施例描述中所需要使用的附图作一简单地介绍，显而易见地，下面描述中的附图是本申请的一些实施例，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，还可以根据这些附图获得其它的附图。
图1为本申请一实施例的一种电极组件的立体结构示意图；
图2为图1的电极组件沿垂直于卷绕轴线K的方向的横截面的结构示意图；
图3为本申请一实施例的一种电极组件在其弯折区的局部结构示意图；
图4为本申请另一实施例的电极组件的弯折区展平之后的阻挡层分布的结构示意图；
图5为本申请另一实施例的电极组件的弯折区展平之后的另一种阻挡层分布的结构示意图；
图6为本申请另一实施例的电极组件的弯折区展平之后的另一种阻挡层分布的结构示意图；
图7为本申请另一实施例的一种负极极片的结构示意图；
图8为本申请另一实施例中一种正极极片的结构示意图；
图9为图8中A-A方向的截面结构示意图；
图10为图8中B-B方向的截面结构示意图；
图11为本申请另一实施例的一种扁平体形状的电极组件垂直于卷绕轴线的横截面的结构示意图；
图12为本申请另一实施例的另一种扁平体形状的电极组件垂直于卷绕轴线的横截面的结构示意图；
图13为本申请另一实施例的另一种扁平体形状的电极组件垂直于卷绕轴线的横截面的结构示意图；
图14为本申请另一实施例的另一种扁平体形状的电极组件垂直于卷绕轴线的横截面的结构示意图；
图15为本申请另一实施例的另一种扁平体形状的电极组件垂直于卷绕轴线的横截面的结构示意图；
图16为本申请另一实施例的另一种扁平体形状的电极组件垂直于卷绕轴线的横截面的结构示意图；
图17为本申请另一实施例的另一种扁平体形状的电极组件垂直于卷绕轴线的横截面的结构示意图；
图18为本申请另一实施例的一种扁平体形状的电极组件垂直于卷绕轴线的横截面的结构示意图；
图19为本申请另一实施例的一种扁平体形状的电极组件垂直于卷绕轴线的横截面的结构示意图；
图20为本申请另一实施例的一种电池单体的结构示意图；
图21为本申请另一实施例的一种电池模组的结构示意图；
图22为本申请另一实施例的一种电池的结构示意图；
图23为本申请另一实施例的一种用电装置的结构示意图；
图24为本申请另一实施例的一种电极组件的制造方法的流程示意图；
图25为本申请的另一实施例一种电极组件的制造设备结构示意。
具体实施方式
为使本申请实施例的目的、技术方案和优点更加清楚，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作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。
除非另有定义，本文所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同；本文中在申请的说明书中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本申请；本申请的说明书和权利要求书及上述附图说明中的术语“包括”和“具有”以及它们的任何变形，意图在于覆盖不排它的包含。
在本文中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。本领域技术人员显式地和隐式地理解的是，本文所描述的实施例可以与其它实施例相结合。
本文中术语“和/或”，仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
在本申请的描述中，需要理解的是，术语“中心”、“纵向”、“横向”、“长度”、“宽度”、“厚度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”、“顺时针”、“逆时针”、“轴向”、“径向”、“周向”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。此外，本申请的说明书和权利要求书或上述附图中的术语“第一”、“第二”等是用于区别不同对象，而不是用于描述特定顺序，可以明示或者隐含地包括一个或者更多个该特征。在本申请的描述中，除非另有说明，“多个”的含义是两个或两个以上。
在本申请的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通。对于本领域的普通技术人员而言，可以具体情况理解上述术语在本申请中的具体含义。
为使得锂离子电池体积更小，能量密度更高，锂离子电池的电极组件中的正极极片、负极极片和隔离膜可以进行卷绕，然后压实。例如，如图1所示，为一种电极组件的立体结构示意图，该电极组件包括负极极片、正极极片和隔离膜，其中，负极极片、正极极片和隔离膜层叠后绕卷绕轴线K卷绕形成卷绕结构，隔离膜为一种绝缘膜，用于隔开负极极片和正极极片，防止负极极片和正极极片短路，该电极组件的卷绕结构为扁平体形状，该电极组件沿垂直于卷绕轴线K的方向的横截面的结构示意图可以如图2所示。
结合图1和图2，该电极组件包括平直区100和位于该平直区100两端的弯折区200。平直区100是指该卷绕结构中具有平行结构的区域，即在该平直区100内的负极极片101、正极极片102和隔离膜103相互基本平行，即电极组件在平直区100的每层负极极片101、正极极片102和隔离膜103的表面均为平面。弯折区200是指该卷绕结构中具有弯折结构的区域，即在该弯折区200内的负极极片101、正极极片102和隔离膜103均弯折，即电极组件在弯折区200的每层负极极片101、正极极片102和隔离膜103的表面均为曲面，该弯折区200具有弯折方向L，该弯折方向L可以理解为沿弯折区电极组件的表面指向平直区的方向，例如，该弯折方向L在该弯折区200沿该卷绕结构的卷绕方向。
负极极片101的表面具有由负极活性物质组成的负极活性物质层，正极极片102的表面具有由正极活性物质组成的正极活性物质层，例如，正极活性物质可为锰酸锂、钴酸锂、磷酸铁锂或者镍钴锰酸锂，负极活性物质可以是石墨或硅。
锂离子电池在充电时，锂离子从正极脱嵌并嵌入负极，但是可能会发生一些异常情况，例如，负极嵌锂空间不足、锂离子嵌入负极阻力太大或锂离子过快的从正极脱嵌，脱嵌的锂离子无法等量的嵌入负极极片的负极活性物质层，无法嵌入负极极片的锂离子只能在负极表面得电子，从而形成银白色的金属锂单质，这就是析锂现象。析锂不仅使锂离子电池性能下降，循环寿命大幅缩短，还限制了锂离子电池的快充容量。除此之外，锂离子电池发生析锂时，析出来的锂金属非常活泼，在较低的温度下便可 以与电解液发生反应，造成电池自产热起始温度(Tonset)降低和自产热速率增大，严重危害电池的安全。再者，析锂严重时，脱嵌的锂离子可以在负极极片表面形成锂结晶，而锂结晶容易刺破隔离膜，造成相邻的正极极片和负极极片具有短路的风险。
发明人在研发过程中发现电极组件在其弯折区经常发生析锂现象，经过进一步研究发现，发明人找到了造成该析锂现象的原因是活性物质脱落导致，主要是因为负极活性物质是涂覆于负极极片的表面，正极活性物质是涂覆于正极极片的表面，而位于转弯区的正极极片和负极极片需要进行弯折，所以可能会导致各自的活性物质脱落，称之为掉粉现象，尤其是弯折区最内层的极片，其弯折程度最大，更容易导致活性物质脱落。由于活性物质的脱落，尤其是负极极片上活性物质的脱落，可能导致该负极极片的负极活性物质层的嵌锂位少于其相邻的正极极片的正极活性物质层能够提供的锂离子数量，因此，锂电池在充电时，容易发生析锂现象。
有鉴于此，本申请欲提供一种电极组件，该电极组件包括负极极片、正极极片和隔离膜，其中，负极极片、正极极片和隔离膜层叠后可以是绕卷绕轴线形成卷绕结构，例如，扁平体的卷绕结构，负极极片、正极极片和隔离膜层叠后也可以是以Z字形状连续折叠，电极组件不论是由卷绕而形成，还是以Z字形状连续折叠而形成，该电极组件均包括平直区和连接该平直区两端的弯折区，为降低或避免析锂，在弯折区的任意相邻的正极极片和负极极片之间设置阻挡层，尤其在弯折区最内侧的相邻的正极极片和负极极片之间设置阻挡层，该阻挡层用于在该弯折区阻挡从正极极片的正极活性物质层脱出的至少一部分锂离子，使得被阻挡层阻挡的离子不能嵌入该弯折区该正极极片相邻的负极极片的负极活性物质层，使得该弯折区的该负极极片的负极活性物质层的嵌锂位与其相邻的正极极片的正极活性物质层能够提供的锂离子数量基本相同，所以可以降低或避免析锂的发生。
电极组件不论是由卷绕而形成，还是以Z字形状连续折叠而形成，该电极组件均包括平直区和连接该平直区两端的弯折区，为描述简洁，本实施例的电极组件以扁平体卷绕结构为例进行描述，例如，该扁平体卷绕结构的其中一个弯折区C和平直区P的结构可以如图3所示，为本申请一实施例的一种电极组件在其弯折区的局部结构示意图，电极组件在其弯折区C包括正极极片1、负极极片2和用于隔离正极极片1和负极极片2的隔离膜3，其中，隔离膜3可以独立于相邻的正极极片1和负极极片2之间，也可以涂覆于正极极片1或负极极片2的表面。
隔离膜3具有电子绝缘性，用于隔离相邻的正极极片1和负极极片2，防止相邻 的正极极片1和负极极片2短路。隔离膜3具有大量贯通的微孔，能够保证电解质离子自由通过，对锂离子有很好的透过性，所以，隔离膜3基本上不能阻挡锂离子通过。例如，隔离膜3包括隔膜基层和位于隔膜基层表面的功能层，隔膜基层可以是聚丙烯、聚乙烯、乙烯—丙烯共聚物、聚对苯二甲酸丁二醇酯等的至少一种，功能层可以是陶瓷氧化物和粘结剂的混合物层。
本申请的实施例的电极组件在其弯折区C还具有阻挡层4，其中，至少一部分阻挡层4位于相邻的正极极片1和负极极片2之间，用于阻挡从正极极片1脱出的至少一部分离子嵌入弯折区C的负极极片2。
通过在弯折区C的相邻的正极极片1和负极极片2之间设置阻挡层4，可以有效降低或避免析锂现象。相邻的正极极片1和负极极片2之间设置阻挡层4，在充电时，正极极片1的正极活性物质层(例如，弯折区C的正极活性物质层)脱出的离子至少一部分被阻挡层4阻挡，使得被阻挡层4阻挡的离子不能嵌入负极极片2在弯折区C的负极活性物质层，使得当负极极片2发生负极活性物质脱落时，降低析锂的发生，即虽然负极极片2因为负极活性物质脱落导致嵌锂位减少，但由于阻挡层4阻挡与负极极片2相邻的正极极片1脱出的至少一部分锂离子，所以，可以降低甚至避免析锂的发生。
在本申请的另一实施例中，阻挡层4为了阻挡锂离子通过，阻挡层4的材质可以包括无机氧化物和/或高分子聚合物。
在本申请的另一实施例中，无机氧化物可以是氧化镁(MgO)、氧化钙(CaO)、勃姆石、硅灰石、硫酸钡(BaSO4)、硫酸钙(CaSO4)、碳酸钙(CaCO3)、氧化铝(Al2O3)和二氧化硅(SiO2)中的至少一种。
在本申请的另一实施例中，高分子聚合物可以是聚丙烯(polypropylene)、聚氯乙烯(Polyvinyl chloride，PVC)、聚乙烯(polyethylene，PE)、环氧树脂、聚丙烯酸酯和聚氨酯橡胶中的至少一种。
在本申请的另一实施例中，阻挡层4可以为胶带或胶纸。胶带包括胶粘剂和基材，其中，基材的材质可以包括聚乙烯和/或乙烯-醋酸乙烯共聚物(Ethylene Vinyl Acetate Copolymer，EVA)制成等。胶纸的材质包括聚苯二甲酸乙二酯、聚偏氟乙烯、聚胺酯、聚丙烯酸钠、丁苯橡胶、聚醚酰亚胺、羧甲基纤维素和丙烯酸酯中的至少一种。
在本申请的另一实施例中，可以是一片正极极片1和一片负极极片2层叠后进行卷绕或折叠，也可以是至少一片(例如，两片或两片以上)正极极片1和至少一片(例 如，两片或两片以上)负极极片2层叠后进行卷绕或折叠，并形成弯折区C，当电极组件在弯折区C具有多层正极极片1和多层负极极片2时，弯折区C包括正极极片1和负极极片2交替分布的结构，至少一层相邻的正极极片1和负极极片2之间包括阻挡层4。弯折区C相邻的正极极片1和负极极片2是指该弯折区C内一层正极极片1和一层负极极片2相邻且它们之间没有包括另一层正极极片1或另一层负极极片2。
在本申请的另一实施例中，该弯折区C除包括正极极片1和负极极片2交替分布结构外，该弯折区C(例如，该弯折区C的最内侧和/或最外侧)还可以存在相邻两层正极极片1之间不存在负极极片2的结构，或者，相邻两层负极极片2之间不存在正极极片1的结构，则该相邻两层正极极片1或相邻两层负极极片2之间可以不设置阻挡层4，即阻挡层4设置于相邻正极极片1和负极极片2之间。
在本申请的另一实施例中，电极组件在弯折区C一般是最内侧的极片弯折程度最大，即最内侧极片的活性物质脱落的几率最大或者活性物质脱落最严重，该最内侧的极片可以是正极极片1或者负极极片2。例如，当最内侧的极片为负极极片2时，为尽可能降低析锂的发生，弯折区C内至少最内侧的相邻正极极片1和负极极片2之间具有阻挡层4。这样，可以减少最内侧的相邻正极极片和负极极片之间的析锂现象，提高安全性能。当弯折区C最内侧的极片为负极极片2时，可以提高正极极片1的活性物质的利用效率。
其中，阻挡层4位于相邻的正极极片1和负极极片2之间，既可以是阻挡层4独立地位于相邻的正极极片1和负极极片2之间，也可以是阻挡层4附接在正极极片1、负极极片2或隔离膜3的任意表面。其中，阻挡层4独立地位于相邻的正极极片1和负极极片2之间，是指阻挡层4分别与正极极片1和负极极片2分离式地层叠，即不具有粘附或涂覆关系，有利于阻挡层4的安装；而附接是指粘附或者涂覆或者喷涂，通过附接，可以减少阻挡层4在电池单体使用过程中的位置移动。
例如，正极极片1的一个表面或两个表面附接阻挡层4，和/或，负极极片2的一个表面或两个表面附接阻挡层4。
在本申请的另一实施例中，阻挡层4独立于弯折区C的相邻的正极极片1和隔离膜3之间，或者，阻挡层4独立于弯折区C的相邻的负极极片2和隔离膜3之间，或者，阻挡层4附接于隔离膜3的一个表面或两个表面。阻挡层4独立于弯折区C的相邻的正极极片1和隔离膜3之间，或者，阻挡层4独立于弯折区C的相邻的负极极片2和隔离膜3之间，是指阻挡层4分别与正极极片1、负极极片2和隔离膜3分离式 地层叠，即不具有粘附或涂覆关系。
在本申请的另一实施例中，阻挡层4沿弯折方向L延伸的两端均位于弯折区C，即阻挡层4全部均位于弯折区C。本实施例中，电极组件还包括与弯折区C相连接的平直区P，弯折方向L是指沿着弯折区C的曲面且指向平直区P的方向，垂直于弯折方向L的方向是指与弯折方向L垂直的方向。
在本申请的另一实施例中，阻挡层4沿弯折方向L延伸的一端位于平直区P，另一端位于弯折区C。
在本申请的另一实施例中，为尽可能阻挡更多的锂离子，阻挡层4在弯折区C尽可能具有较大面积，例如，阻挡层4沿弯折方向L延伸的两端均位于平直区P，即阻挡层4除了位于弯折区C之外，还延伸至平直区P。
在本申请的另一实施例中，阻挡层4沿弯折方向L延伸的两端均位于弯折区C与平直区P的交界处，或者阻挡层4沿弯折方向L延伸的两端均临近弯折区C与平直区P的交界处。
在本申请的另一实施例中，相邻的正极极片1和负极极片2，当负极极片2位于弯折区C最内侧时，最内侧的负极极片2曲率最大的部位负极活性物质脱落最严重，所以，不论阻挡层4沿弯折方向L怎么延伸，阻挡层4尽可能阻挡从正极极片1脱出的锂离子嵌入负极极片2中曲率最大的部位，即阻挡层4与负极极片2中曲率最大的部位相对设置，用于覆盖负极极片2中曲率最大的部位。这样，可以使得负极极片2的曲率最大的部位不嵌入锂离子或者嵌入少量锂离子，从而减少析锂现象的发生。
在本申请的另一实施例中，弯折区C最内侧的负极极片2曲率最大的部位为弯折区C最内侧的负极极片2曲面上沿垂直于弯折方向L的一条线(例如，该线可以为直线)，且该线上任意一点的曲率大于该点沿弯折方向L两侧的该弯折区C最内侧的负极极片2的曲面的曲率。例如，当负极极片2在弯折区C沿弯折方向L对称弯折时，弯折区C最内侧的负极极片2曲率最大的部位为负极极片2在该弯折区C的中间部位。
阻挡层4虽然在弯折区C面积越大，越能阻挡更多的锂离子，但是，阻挡锂离子越多，弯折区C的能量密度就越低，导致电极组件的能量密度越低，因此，在本申请的另一实施例中，对于弯折区C的相邻正极极片1和负极极片2，可以适当使得有锂离子从正极极片1脱出并嵌入到负极极片2中，以保证一定能量密度。
例如，如图4所示，为本申请另一实施例的电极组件的弯折区C展平之后的阻挡层分布的结构示意图，弯折区C的相邻的正极极片1和负极极片2之间包括非连续的 多个阻挡层4，非连续的多个阻挡层4沿弯折方向L间隔分布，使得部分锂离子没有被阻挡层4挡住，即部分锂离子从相邻两个阻挡层4之间穿过而嵌入到负极极片2的负极活性物质层。例如，非连续的多个阻挡层4附接在正极极片1的表面上。这样，既可以阻挡部分锂离子的通过，减少析锂现象的发生，又可以保证电极组件的能量密度。
再例如，如图5所示，为本申请另一实施例的电极组件的弯折区展平之后的另一种阻挡层分布的结构示意图，弯折区的相邻的正极极片1和负极极片2之间包括非连续的多个阻挡层4，非连续的多个阻挡层4沿垂直于弯折方向L的K方向间隔分布，使得部分锂离子没有被阻挡层4挡住，即部分锂离子从两个相邻的阻挡层4之间穿过而嵌入到负极极片2的负极活性物质层。例如，非连续的多个阻挡层4附接在正极极片1的表面上。其中，垂直于弯折方向L的K方向可以为正极极片1和负极极片2的宽度方向。当电极组件是卷绕结构时，垂直于弯折方向L的K方向为卷绕结构的卷绕轴线方向。
再例如，如图6所示，为本申请另一实施例的电极组件的弯折区展平之后的另一种阻挡层分布的结构示意图，阻挡层4附接在正极极片1的表面上，阻挡层4具有至少一个通孔41，用于部分锂离子通过而嵌入到负极极片2的负极活性物质层。
在本申请的另一实施例中，阻挡层4的孔隙率小于隔离膜3的孔隙率，使得阻挡层4可以更有效地阻挡锂离子的通过。其中，孔隙率是指块状材料中孔隙体积与材料在自然状态下总体积的百分比。一般情况下，孔隙率的测试方法为真密度测试方法。
为使得阻挡锂离子和保持能量密度达到比较好的平衡，阻挡层4的厚度为A微米，阻挡层4的孔隙率为B，其中，A和B满足以下关系式：3.5微米≤A/B≤2000微米，可选地，7微米≤A/B≤1000微米。这样，既可以保证电极组件的安全又可以保证电极组件能量密度，在安全性能和能量密度之间取得一个较好的平衡。A过小，即表示阻挡层4的厚度过小，锂结晶容易刺破阻挡层4，甚至刺破隔离膜3，使得阻挡层4失去阻挡锂离子的作用，可能存在安全风险；B较大，即表示阻挡层4的孔隙率过大，阻挡层4的孔隙率越大，通过保护层4的锂离子越多，可能导致析锂现象严重。例如，A/B小于3.5时，表示A较小，即阻挡层4的厚度过小，B较大，即阻挡层4的孔隙率过大，阻挡层4失去阻挡锂离子的作用，可能存在安全风险。A/B大于2000时，A较大，即阻挡层4的厚度过大，B较小，即阻挡层4的孔隙率过小，严重影响电池单体的能量密度。
例如，阻挡层4的厚度为2-200微米(um)，可选地，阻挡层4的厚度为5-100微米，进一步可选地，阻挡层4的厚度为5-50微米。这样，既可以保证电极组件的安全又可以保证电极组件能量密度，在安全性能和能量密度之间取得一个较好的平衡。例如，当阻挡层4的厚度小于2um时，阻挡层4的厚度过小，当析锂严重时，锂结晶会刺破阻挡层4，甚至刺破隔离膜3，使得阻挡层4失去阻挡锂离子的作用，存在安全风险。当阻挡层4的厚度大于500um时，阻挡层4的厚度较大，导致相邻的正极极片1和负极极片2之间的间隙过大，阻挡层4占用空间，可能影响电极组件的能量密度，再者，相邻两层的间隙过大，可能严重影响循环性能。
阻挡层4的孔隙率为10％-70％，可选地，阻挡层4的孔隙率为20％-60％。这样，既可以保证电极组件的安全又可以保证电极组件能量密度，在安全性能和能量密度之间取得一个较好的平衡。例如，当孔隙率小于10％时，大部分或者所有的锂离子会被阻挡层4阻挡，而不能嵌入都到负极极片2中，从而影响电极组件的能量密度；而当孔隙率大于70％时，大部分或几乎所有的锂离子会通过该阻挡层4，则会存在析锂风险，导致锂结晶会刺破阻挡层4，使得阻挡层4失去阻挡锂离子的作用，存在安全风险。
当电极组件具有卷绕结构时，正极极片1和负极极片2的宽度方向与卷绕轴线方向平行，以及，正极极片1和负极极片2的宽度方向与垂直于弯折方向L的方向平行；当电极组件不具有卷绕结构时，正极极片1和负极极片2的宽度方向与垂直于弯折方向L的方向平行，为后续的描述简单，本实施例中，正极极片1和负极极片2的宽度方向、垂直于弯折方向L的方向和卷绕轴线方向统一称为K方向。
负极极片2的结构可以图7所示，为本申请另一实施例的一种负极极片的结构示意图，负极极片2包括负极主体部21和从负极主体部21沿K方向向外延伸的负极极耳部22，负极主体部21的表面上沿K方向的至少部分区域为负极活性物质区211，负极活性物质区211用于涂覆负极活性物质，负极活性物质可以是石墨或硅。
在本申请的另一实施例中，不仅负极主体部21的表面的部分区域设有负极活性物质区211，负极极耳部22的表面且靠近负极主体部21的根部区域也设有负极活性物质区211，即负极极耳部22的部分区域为负极活性物质区211。
在本申请的另一实施例中，如图7所示，负极活性物质区211覆盖负极主体部21的沿方向K的整个表面。
在本申请的另一实施例中，正极活性物质可能没有覆盖正极极片1的整个表面， 例如，如图8所示，为本申请另一实施例中一种正极极片的结构示意图。
正极极片1包括正极主体部11和沿K方向向正极主体部11外部延伸的至少一个正极极耳部12，正极主体部11的表面至少部分区域为正极活性物质区111，在该正极活性物质区111可以涂覆正极活性物质，例如，正极活性物质可以是三元材料、锰酸锂或磷酸铁锂。
在本申请的另一实施例中，正极主体部11的表面还包括与正极活性物质区111相邻的第一绝缘层涂覆区112，第一绝缘层涂覆区112位于正极活性物质区111邻近正极极耳部12的一侧，第一绝缘层涂覆区112用于涂覆绝缘物质，用于绝缘隔离正极活性物质区111和正极极耳部12，例如，如图9所示，为图8中A-A方向的截面结构示意图，正极极片1的集流体10的两个表面具有正极活性物质区111，正极极耳部12为正极极片1的集流体10的一部分，其中，集流体10的材质可以为铝。
例如，正极活性物质区111和第一绝缘层涂覆区112在正极主体部11的表面上沿正极主体部11的宽度方向(即K方向)呈两端分布，且正极极耳部12与第一绝缘层涂覆区112属于正极主体部11的同一端。
在本申请的另一实施例中，正极活性物质区111和第一绝缘层涂覆区112在正极主体部11的表面上为两个基本平行的区域，且沿K方向在正极主体部11的表面上呈两层分布。
在本申请的另一实施例中，第一绝缘层涂覆区112可以位于正极主体部11与正极极耳部12相互连接的部分，例如，第一绝缘层涂覆区112位于正极主体部11的表面上且与正极极耳部12相互连接的部分，用于隔开正极极耳部12的表面和正极活性物质区111。在本申请的另一实施例中，不仅正极主体部11的表面上设有第一绝缘层涂覆区112，在正极极耳部12靠近正极主体部11的根部区域也设有第二绝缘层涂覆区121，第二绝缘层涂覆区121用于涂覆绝缘物质。
在本申请的另一实施例中，第一绝缘层涂覆区112的表面涂覆绝缘物质，绝缘物质包括无机填料和粘接剂。无机填料包括勃姆石、氧化铝、氧化镁、二氧化钛、氧化锆、二氧化硅、碳化硅、碳化硼、碳酸钙、硅酸铝、硅酸钙、钛酸钾、硫酸钡中的一种或几种。粘结剂包括聚偏氟乙烯、聚丙烯腈、聚丙烯酸、聚丙烯酸酯、聚丙烯酸-丙烯酸酯、聚丙烯腈-丙烯酸、聚丙烯腈-丙烯酸酯中的一种或几种。
在本申请的另一实施例中，每片正极极片1可以包括一个或两个或两个以上正极极耳部12，当正极极片1包括两个或两个以上正极极耳部12时，所有正极极耳部12 均位于正极极片1沿K方向的同一侧。
结合图7和图8，当正极极片1和负极极片2相互层叠时，负极极片2的负极活性物质区211沿方向K的两端均超出相邻的正极极片1的正极活性物质区111的对应端，这样，可以保证电极组件的能量密度。例如，负极活性物质区211沿方向K的两端分别为第一端23和第二端24，正极活性物质区111沿方向K的两端分别为第三端13和第四端14，其中，负极活性物质区211的第一端23和正极活性物质区111的第三端13沿方向K位于电极组件的同一侧，且负极活性物质区211的第一端23沿方向K超出正极活性物质区111的第三端13，负极活性物质区211的第二端24和正极活性物质区111的第四端14沿方向K位于电极组件的另一侧，负极活性物质区211的第二端24沿方向K超出正极活性物质区111的第四端14。
负极活性物质区211沿卷绕轴线K的两端超出正极活性物质区111的对应端的尺寸可以相同，也可不同，例如，超出的尺寸范围为0.2毫米～5毫米。
如图10所示，为图8中B-B方向的截面结构示意图，结合图8，阻挡层4附接于正极活性物质区111的表面上，即正极活性物质层的表面上。
为了既能阻挡锂离子，又能节约成本，阻挡层4沿垂直于弯折方向(即方向K)包括第五端42和第六端43，阻挡层4的第五端42超出正极极片1的正极活性物质层和/或阻挡层4的第六端43超出正极活性物质层，即阻挡层4的第五端42沿方向K超出正极活性物质区111的第三端13，和/或，阻挡层4的第六端43沿方向K超出正极活性物质区111的第四端14，例如，超出的尺寸范围为0.2毫米～5毫米。这样，可以阻挡较多锂离子的通过，减少析锂现象的发生。
在本申请的另一实施例中，阻挡层4的第五端42和第六端43，均不超过负极极片2的负极活性物质层的对应端，即负极极片2的负极活性物质区的第一端23超出阻挡层4的第五端42，和/或，负极极片2的负极活性物质区的第二端24超出阻挡层4的第六端43。这样，负极极片2超出阻挡层4的部分可以嵌入锂离子，可以保证电极组件的能量密度。
上述实施例仅仅概况性地描述阻挡层分别与正极极片和负极极片的位置关系以及阻挡层的结构特征，为了更清楚阻挡层分别与正极极片和负极极片的位置关系以及阻挡层的结构，下述以几种具有卷绕结构的电极组件分别进行详细的描述。
如图11所示，为本申请另一实施例的一种扁平体形状的电极组件垂直于卷绕轴线的横截面的结构示意图，电极组件包括负极极片91、正极极片92、隔离膜93、第 一阻挡层94、第二阻挡层95和第三阻挡层96，其中，隔离膜93位于负极极片91与正极极片92之间，隔离膜93为两片，在图11的电极组件的截面图中通过卷绕的两条虚线表示，负极极片91、正极极片92和隔离膜93叠加后绕卷绕轴线卷绕成扁平体形状的卷绕结构。
本实施例的负极极片91、正极极片92和隔离膜93的相关技术特征，可以参考前述图1-10所对应实施例的描述，在此不再赘述。
本实施例中，电极组件的卷绕结构包括平直区9A和位于平直区9A两侧的第一弯折区9B1和第二弯折区9B2，其中，平直区9A分别与第一弯折区9B1和第二弯折区9B2的划分，分别通过直线虚线进行划分。
电极组件在第一弯折区9B1和第二弯折区9B2包括的负极极片91和正极极片92依次交替层叠，相邻负极极片91和正极极片92之间具有隔离膜93，其中，第一弯折区9B1和第二弯折区9B2最内侧的极片均为负极极片91，第一弯折区9B1和第二弯折区9B2的至少最内侧的正极极片92的内侧表面设有(例如，附接)阻挡层，例如，第一弯折区9B1和第二弯折区9B2的每层正极极片92的内侧表面设有(例如，附接)阻挡层。本实施例中，正极极片92的内侧表面是指正极极片92朝向卷绕轴线的表面，或者朝向卷绕结构内部的表面。
例如，第一弯折区9B1具有多层极片，例如三层极片，第一弯折区9B1的最内层(也可以称为第一层)和最外层(也可以称为第三层)的极片均为负极极片91，最内层极片和最外层的极片之间的极片(也可以称为第二层极片)为正极极片92，该正极极片92为第一弯折区9B1最内侧的正极极片，第一阻挡层94附接于第一弯折区9B1的正极极片92的内侧表面。
第二弯折区9B2具有多层极片，例如五层极片，沿卷绕结构从内到外的方向，第二弯折区9B2的负极极片91和正极极片92依次交替层叠，第二弯折区9B2的最内层的极片为负极极片91，第二弯折区9B2的每层正极极片92的内侧表面附接有阻挡层。
例如，沿卷绕结构从内到外的方向，第二弯折区9B2依次包括第一、二、三、四和五层极片，第一、三和五层极片为负极极片91，第二和四层极片为正极极片92，第二弯折区9B2的每层正极极片92的内侧表面均附接有阻挡层。例如，第二阻挡层95附接于第二弯折区9B2的第二层极片(其为正极极片92)的内侧表面。第三阻挡层96附接于第二弯折区9B2的第四层极片(其为正极极片92)的内侧表面。
本实施例中，第一阻挡层94、第二阻挡层95和第三阻挡层96沿弯折方向(即沿 卷绕方向)的两端，分别位于弯折区与平直区的交界处，例如，第一阻挡层94沿卷绕方向的两端分别位于第一弯折区9B1与平直区9A的交界处，第二阻挡层95和第三阻挡层96沿卷绕方向的两端分别位于第二弯折区9B2与平直区9A的交界处。
本实施例中，第一阻挡层94、第二阻挡层95和第三阻挡层96的功能、结构和分布方式等相关内容，均可以参考前述图1-10实施例所描述的阻挡层的相关内容，在此不再赘述。
如图12所示，为本申请另一实施例的另一种扁平体形状的电极组件垂直于卷绕轴线的横截面的结构示意图，电极组件包括负极极片1001、正极极片1002、隔离膜1003、第一阻挡层1004、第二阻挡层1005和第三阻挡层1006，其中，隔离膜1003位于负极极片1001与正极极片1002之间，负极极片1001、正极极片1002和隔离膜1003叠加后绕卷绕轴线卷绕成扁平体形状的卷绕结构。
本实施例的负极极片1001、正极极片1002和隔离膜1003的相关技术特征，可以参考前述图1-10所对应实施例的描述，在此不再赘述。
本实施例中，电极组件的卷绕结构包括平直区10A和位于平直区10A两侧的第一弯折区10B1和第二弯折区10B2。
本实施例的电极组件与图11对应的实施例描述的电极组件基本类似，其不同之处可以如下。
第一弯折区10B1和第二弯折区10B2的至少最内侧的正极极片1002的外侧表面设有(例如，附接)阻挡层，例如，第一弯折区10B1和第二弯折区10B2的每层正极极片1002的外侧表面均设有(例如，附接)阻挡层。本实施例中，正极极片1002的外侧表面是指正极极片1002背向卷绕轴线的表面，或者背向卷绕结构内部的表面。
例如，第一阻挡层1004附接于第一弯折区10B1的正极极片1002的外侧表面。
例如，第二阻挡层1005附接于第二弯折区10B2的第二层极片(其为正极极片1002)的外侧表面。第三阻挡层1006附接于第二弯折区10B2的第四层极片(其为正极极片1002)的外侧表面。
本实施例中，第一阻挡层1004沿卷绕方向的两端分别位于第一弯折区10B1与平直区10A的交界处，第二阻挡层1005和第三阻挡层1006沿卷绕方向的两端分别位于第二弯折区10B2与平直区10A的交界处。
本实施例中，第一阻挡层1004、第二阻挡层1005和第三阻挡层1006的功能、结构和分布方式等相关内容，还可以参考前述图1-10实施例所描述的阻挡层的相关内 容，在此不再赘述。
如图13所示，为本申请另一实施例的另一种扁平体形状的电极组件垂直于卷绕轴线的横截面的结构示意图，电极组件包括负极极片1101、正极极片1102、隔离膜1103、第一阻挡层1104、第二阻挡层1105、第三阻挡层1106、第四阻挡层1107和第五阻挡层1108，其中，隔离膜1103位于负极极片1101与正极极片1102之间，负极极片1101、正极极片1102和隔离膜1103叠加后绕卷绕轴线卷绕成扁平体形状的卷绕结构。
本实施例的负极极片1101、正极极片1102和隔离膜1103的相关技术特征，可以参考前述图1-10所对应实施例的描述，在此不再赘述。
本实施例中，电极组件的卷绕结构包括平直区11A和位于平直区11A两侧的第一弯折区11B1和第二弯折区11B2。
本实施例的电极组件与图11对应的实施例描述的电极组件基本类似，其不同之处可以如下。
第一弯折区11B1和第二弯折区11B2的至少最内侧的负极极片1101的内侧表面设有(例如，附接)阻挡层，例如，第一弯折区11B1和第二弯折区11B2的每层负极极片1101的内侧表面均设有阻挡层。本实施例中，负极极片1101的内侧表面是指负极极片1101朝向卷绕轴线的表面，或者朝向卷绕结构内部的表面。
例如，第一阻挡层1104附接于第一弯折区11B1的最内层极片(其为负极极片1101)的内侧表面，第二阻挡层1105附接于最外层的极片(其为负极极片1101)的内侧表面。
例如，第三阻挡层1106附接于第二弯折区11B2的第一层极片(其为负极极片1101)的内侧表面。第四阻挡层1107附接于第二弯折区11B2的第三层极片(其为负极极片1101)的内侧表面。第五阻挡层1108附接于第二弯折区11B2的第五层极片(其为负极极片1101)的内侧表面。
本实施例中，第一阻挡层1104和第二阻挡层1105沿卷绕方向的两端分别位于第一弯折区11B1与平直区11A的交界处，第三阻挡层1106、第四阻挡层1107和第五阻挡层1108沿卷绕方向的两端分别位于第二弯折区11B2与平直区11A的交界处。
本实施例中，第一阻挡层1104、第二阻挡层1105、第三阻挡层1106、第四阻挡层1107和第五阻挡层1108的功能、结构和分布方式等相关内容，均可以参考前述图1-10实施例所描述的阻挡层的相关内容，在此不再赘述。
如图14所示，为本申请另一实施例的另一种扁平体形状的电极组件垂直于卷绕轴线的横截面的结构示意图，电极组件包括负极极片1201、正极极片1202、隔离膜1203、第一阻挡层1204、第二阻挡层1205、第三阻挡层1206、第四阻挡层1207和第五阻挡层1208，其中，隔离膜1203位于负极极片1201与正极极片1202之间，负极极片1201、正极极片1202和隔离膜1203叠加后绕卷绕轴线卷绕成扁平体形状的卷绕结构。
本实施例的负极极片1201、正极极片1202和隔离膜1203的相关技术特征，可以参考前述图1-10所对应实施例的描述，在此不再赘述。
本实施例中，电极组件的卷绕结构包括平直区12A和位于平直区12A两侧的第一弯折区12B1和第二弯折区12B2。
本实施例的电极组件与图11对应的实施例描述的电极组件基本类似，其不同之处可以如下。
第一弯折区12B1和第二弯折区12B2的至少最内侧的负极极片1201的外侧表面设有(例如，附接)阻挡层，例如，第一弯折区12B1和第二弯折区12B2的每层负极极片1201的外侧表面均设有阻挡层。本实施例中，负极极片1201的外侧表面是指负极极片1201背向卷绕轴线的表面，或者背向卷绕结构内部的表面。
例如，第一阻挡层1204附接于第一弯折区12B1的最内层极片(其为负极极片1201)的外侧表面，第二阻挡层1205附接于最外层的极片(其为负极极片1201)的外侧表面。
例如，第三阻挡层1206附接于第二弯折区12B2的第一层极片(其为负极极片1201)的外侧表面。第四阻挡层1207附接于第二弯折区12B2的第三层极片(其为负极极片1201)的外侧表面。第五阻挡层1208附接于第二弯折区12B2的第五层极片(其为负极极片1201)的外侧表面。
本实施例中，第一阻挡层1204和第二阻挡层1205沿卷绕方向的两端分别位于第一弯折区12B1与平直区12A的交界处，第三阻挡层1206、第四阻挡层1207和第五阻挡层1208沿卷绕方向的两端分别位于第二弯折区12B2与平直区12A的交界处。
本实施例中，第一阻挡层1204、第二阻挡层1205、第三阻挡层1206、第四阻挡层1207和第五阻挡层1208的功能、结构和分布方式等相关内容，均可以参考前述图1-10实施例所描述的阻挡层的相关内容，在此不再赘述。
如图15所示，为本申请另一实施例的另一种扁平体形状的电极组件垂直于卷绕 轴线的横截面的结构示意图，电极组件包括负极极片1301、正极极片1302、隔离膜1303和多个阻挡层1304，其中，隔离膜1303位于负极极片1301与正极极片1302之间，负极极片1301、正极极片1302和隔离膜1303叠加后绕卷绕轴线卷绕成扁平体形状的卷绕结构。
本实施例的负极极片1301、正极极片1302和隔离膜1303的相关技术特征，可以参考前述图1-10所对应实施例的描述，在此不再赘述。
本实施例中，电极组件的卷绕结构包括平直区13A和位于平直区13A两侧的第一弯折区13B1和第二弯折区13B2。
本实施例的电极组件与图11对应的实施例描述的电极组件基本类似，其不同之处可以如下。
第一弯折区13B1和第二弯折区13B2的至少最内侧隔离膜1303的内侧表面附接有阻挡层1304，例如，第一弯折区13B1和第二弯折区13B2的每层隔离膜1303的内侧表面附接有阻挡层1304。本实施例中，隔离膜1303的内侧表面是指隔离膜1303朝向卷绕轴线的表面，或者朝向卷绕结构内部的表面。
本实施例中，第一弯折区13B1的每个阻挡层1304沿卷绕方向的两端分别位于第一弯折区13B1与平直区13A的交界处，第二弯折区13B2的每个阻挡层1304沿卷绕方向的两端分别位于第二弯折区12B2与平直区12A的交界处。
本实施例中，每个阻挡层1304的功能、结构和分布方式等相关内容，均可以参考前述图1-10实施例所描述的阻挡层的相关内容，在此不再赘述。
如图16所示，为本申请另一实施例的另一种扁平体形状的电极组件垂直于卷绕轴线的横截面的结构示意图，电极组件包括负极极片1401、正极极片1402、隔离膜1403和多个阻挡层1404，其中，隔离膜1403位于负极极片1401与正极极片1402之间，负极极片1401、正极极片1402和隔离膜1403叠加后绕卷绕轴线卷绕成扁平体形状的卷绕结构。
本实施例的负极极片1401、正极极片1402和隔离膜1403的相关技术特征，可以参考前述图1-10所对应实施例的描述，在此不再赘述。
本实施例中，电极组件的卷绕结构包括平直区14A和位于平直区14A两侧的第一弯折区14B1和第二弯折区14B2。
本实施例的电极组件与图11对应的实施例描述的电极组件基本类似，其不同之处可以如下。
第一弯折区14B1和第二弯折区14B2的至少最内侧的隔离膜1403的外侧表面附接有阻挡层1404，例如，第一弯折区14B1和第二弯折区14B2的每层隔离膜1403的外侧表面附接有阻挡层1404。本实施例中，隔离膜1403的外侧表面是指隔离膜1403背向卷绕轴线的表面，或者背向卷绕结构内部的表面。
本实施例中，第一弯折区14B1的每个阻挡层1404沿卷绕方向的两端分别位于第一弯折区14B1与平直区14A的交界处，第二弯折区14B2的每个阻挡层1404沿卷绕方向的两端分别位于第二弯折区12B2与平直区12A的交界处。
本实施例中，每个阻挡层1404的功能、结构和分布方式等相关内容，均可以参考前述图1-10实施例所描述的阻挡层的相关内容，在此不再赘述。
如图17所示，为本申请另一实施例的另一种扁平体形状的电极组件垂直于卷绕轴线的横截面的结构示意图，电极组件包括负极极片1501、正极极片1502、隔离膜1503和多个阻挡层1504，其中，隔离膜1503位于负极极片1501与正极极片1502之间，负极极片1501、正极极片1502和隔离膜1503叠加后绕卷绕轴线卷绕成扁平体形状的卷绕结构。
本实施例的负极极片1501、正极极片1502和隔离膜1503的相关技术特征，可以参考前述图1-10所对应实施例的描述，在此不再赘述。
本实施例中，电极组件的卷绕结构包括平直区15A和位于平直区15A两侧的第一弯折区15B1和第二弯折区15B2。
电极组件在第一弯折区15B1和第二弯折区15B2包括的负极极片1501和正极极片1502依次交替层叠，第一弯折区15B1和第二弯折区15B2的任意相邻负极极片1501和正极极片1502之间具有隔离膜1503，其中，第一弯折区15B1和第二弯折区15B2最内侧的极片均为负极极片1501，第一弯折区15B1和第二弯折区15B2的至少最内侧的正极极片1502的内侧表面和外侧表面均设有阻挡层1504，例如，第一弯折区15B1和第二弯折区15B2的每层正极极片1502的内侧表面和外侧表面均设有阻挡层1504。本实施例中，正极极片1502的内侧表面是指正极极片1502朝向卷绕轴线的表面，或者朝向卷绕结构内部的表面，正极极片1502的外侧表面是指正极极片1502背向卷绕轴线的表面，或者背向卷绕结构内部的表面。
例如，第一弯折区15B1具有多层极片，例如三层极片，第一弯折区15B1的最内层(也可以称为第一层)和最外层(也可以称为第三层)的极片均为负极极片1501，第一弯折区15B1的最内层极片和最外层的极片之间的极片(也可以称为第二层极片) 为正极极片1502，第一弯折区15B1的正极极片1502的内侧表面和外侧表面均设有(例如，附接)阻挡层1504。
第二弯折区15B2具有多层极片，例如五层极片，沿卷绕结构从内到外的方向，第二弯折区15B2的负极极片1501和正极极片1502依次交替层叠，第二弯折区15B2的最内层的极片为负极极片1501，第二弯折区15B2的每层正极极片1502的内侧表面和外侧表面均设有(例如，附接)阻挡层1504。
例如，沿卷绕结构从内到外的方向，第二弯折区15B2依次包括第一、二、三、四和五层极片，第一、三和五层极片为负极极片1501，第二和四层极片为正极极片1502，第二弯折区15B2的第二和四层极片的内侧表面和外侧表面均设有阻挡层1504。
本实施例中，每个阻挡层1504沿弯折方向(即沿卷绕方向)的两端，分别位于弯折区与平直区的交界处，例如，第一弯折区15B1的每个阻挡层1504沿卷绕方向的两端分别位于第一弯折区15B1与平直区15A的交界处，第二弯折区15B2的每个阻挡层1504沿卷绕方向的两端分别位于第二弯折区15B2与平直区15A的交界处。
本实施例中，每个阻挡层1504的功能、结构和分布方式等相关内容，均可以参考前述图1-10实施例所描述的阻挡层的相关内容，在此不再赘述。
如图18所示，为本申请另一实施例的一种扁平体形状的电极组件垂直于卷绕轴线的横截面的结构示意图，电极组件包括负极极片1601、正极极片1602、隔离膜1603、第一阻挡层1604、第二阻挡层1605和第三阻挡层1606，其中，隔离膜1603位于负极极片1601与正极极片1602之间，负极极片1601、正极极片1602和隔离膜1603叠加后绕卷绕轴线卷绕成扁平体形状的卷绕结构。
本实施例的负极极片1601、正极极片1602和隔离膜1603的相关技术特征，可以参考前述图1-10所对应实施例的描述，在此不再赘述。
本实施例中，电极组件的卷绕结构包括第一平直区16A1、第二平直区16A2、第一弯折区16B1和第二弯折区16B2，第一平直区16A1和第二平直区16A2相对设置，第一弯折区16B1和第二弯折区16B2相对设置，第一弯折区16B1的两端分别连接第一平直区16A1和第二平直区16A2的同一侧端，第二弯折区16B2的两端分别连接第一平直区16A1和第二平直区16A2的另同一侧端。
电极组件在第一弯折区16B1和第二弯折区16B2包括的负极极片1601和正极极片1602依次交替层叠，相邻负极极片1601和正极极片1602之间具有隔离膜1603，其中，第一弯折区16B1和第二弯折区16B2最内侧的极片均为负极极片1601，第一 弯折区16B1和第二弯折区16B2的至少最内侧的正极极片1602的内侧表面设有(例如，附接)阻挡层，例如，第一弯折区16B1和第二弯折区16B2的每层正极极片1602的内侧表面设有(例如，附接)阻挡层。本实施例中，正极极片1602的内侧表面是指正极极片1602朝向卷绕轴线的表面，或者朝向卷绕结构内部的表面。
例如，第一弯折区16B1具有多层极片，例如三层极片，第一弯折区16B1的最内层(也可以称为第一层)和最外层(也可以称为第三层)的极片均为负极极片1601，最内层极片和最外层的极片之间的极片(也可以称为第二层极片)为正极极片1602，第一阻挡层1604附接于第一弯折区16B1的正极极片1602的内侧表面。
例如，第二弯折区16B2具有多层极片，例如五层极片，沿卷绕结构从内到外的方向，第二弯折区16B2的负极极片1601和正极极片1602依次交替层叠，第二弯折区16B2的最内层的极片为负极极片1601，第二弯折区16B2的每层正极极片1602的内侧表面附接有阻挡层。
例如，沿卷绕结构从内到外的方向，第二弯折区16B2依次包括第一、二、三、四和五层极片，第一、三和五层极片为负极极片1601，第二和四层极片为正极极片1602，第二阻挡层1605附接于第二弯折区16B2的最内侧相邻的负极极片1601和正极极片1602中的正极极片1602的内侧表面上，即第二阻挡层1605附接于第二弯折区16B2的第二层极片(其为正极极片1602)的内侧表面。第三阻挡层1606附接于第二弯折区16B2的第四层极片(其为正极极片1602)的内侧表面。
本实施例中，第一阻挡层1604沿弯折方向(即沿卷绕方向)包括第一端和第二端，第一阻挡层1604的第一端位于第一弯折区16B1，第一阻挡层1604的第二端位于第一平直区16A1。第二阻挡层1605沿弯折方向(即沿卷绕方向)包括第一端和第二端，第二阻挡层1605的第一端位于第二弯折区16B2，第二阻挡层1605的第二端位于第二平直区16A2。第三阻挡层1606沿弯折方向(即沿卷绕方向)包括第一端和第二端，第三阻挡层1606的第一端位于第二弯折区16B2，第三阻挡层1606的第二端位于第二平直区16A2。在本申请的另一实施例这种，第三阻挡层1606的第一端位于第二弯折区16B2，第三阻挡层1606的第二端可以位于第一平直区16A1。
本实施例中，第一阻挡层1604、第二阻挡层1605和第三阻挡层1606的功能、结构和分布方式等相关内容，均可以参考前述图1-10实施例所描述的阻挡层的相关内容，在此不再赘述。
如图19所示，为本申请另一实施例的一种扁平体形状的电极组件垂直于卷绕轴 线的横截面的结构示意图，电极组件包括负极极片1701、正极极片1702、隔离膜1703、第一阻挡层1704、第二阻挡层1705和第三阻挡层1706，其中，隔离膜1703位于负极极片1701与正极极片1702之间，负极极片1701、正极极片1702和隔离膜1703叠加后绕卷绕轴线卷绕成扁平体形状的卷绕结构。
本实施例的负极极片1701、正极极片1702和隔离膜1703的相关技术特征，可以参考前述图1-10所对应实施例的描述，在此不再赘述。
本实施例中，电极组件的卷绕结构包括第一平直区17A1、第二平直区17A2、第一弯折区17B1和第二弯折区17B2，第一平直区17A1和第二平直区17A2相对设置，第一弯折区17B1和第二弯折区17B2相对设置，第一弯折区17B1的两端分别连接第一平直区17A1和第二平直区17A2的同一侧端，第二弯折区17B2的两端分别连接第一平直区17A1和第二平直区17A2的另同一侧端。
电极组件在第一弯折区17B1和第二弯折区17B2包括的负极极片1701和正极极片1702依次交替层叠，相邻负极极片1701和正极极片1702之间具有隔离膜1703，其中，第一弯折区17B1和第二弯折区17B2最内侧的极片均为负极极片1701，第一弯折区17B1和第二弯折区17B2的至少最内侧的正极极片1702的内侧表面设有(例如，附接)阻挡层，例如，第一弯折区17B1和第二弯折区17B2的每层正极极片1702的内侧表面设有(例如，附接)阻挡层。本实施例中，正极极片1702的内侧表面是指正极极片1702朝向卷绕轴线的表面，或者朝向卷绕结构内部的表面。
例如，第一弯折区17B1具有多层极片，例如三层极片，第一弯折区17B1的最内层(也可以称为第一层)和最外层(也可以称为第三层)的极片均为负极极片1701，最内层极片和最外层的极片之间的极片(也可以称为第二层极片)为正极极片1702，第一阻挡层1704附接于第一弯折区17B1的正极极片1702的内侧表面。
第二弯折区17B2具有多层极片，例如五层极片，沿卷绕结构从内到外的方向，第二弯折区17B2的负极极片1701和正极极片1702依次交替层叠，第二弯折区17B2的最内层的极片为负极极片1701，第二弯折区17B2的每层正极极片1702的内侧表面附接有阻挡层。
例如，沿卷绕结构从内到外的方向，第二弯折区17B2依次包括第一、二、三、四和五层极片，第一、三和五层极片为负极极片1701，第二和四层极片为正极极片1702，第二阻挡层1705附接于第二弯折区17B2的最内侧相邻的负极极片1701和正极极片1702中的正极极片1702的内侧表面上，即第二阻挡层1705附接于第二弯折 区17B2的第二层极片(其为正极极片1702)的内侧表面。第三阻挡层1706附接于第二弯折区17B2的第四层极片(其为正极极片1702)的内侧表面。
本实施例中，第一阻挡层1704沿弯折方向(即沿卷绕方向)包括第一端和第二端，第一阻挡层1704的第一端和第二端均位于第一弯折区17B1。第二阻挡层1705沿弯折方向(即沿卷绕方向)包括第一端和第二端，第二阻挡层1705的第一端位于第二弯折区17B2与第一平直区17A1的交界处，第二阻挡层1705的第二端位于第二弯折区17B2与第二平直区17A2的交界处。第三阻挡层1706沿弯折方向(即沿卷绕方向)包括第一端和第二端，第三阻挡层1706的第一端和第二端均位于第二弯折区17B2。
本实施例中，在第二弯折区17B2，沿垂直于卷绕轴线且从电极组件从内到外的方向，每层极片的曲率依次减小，即弯折程度逐次降低，则沿垂直于卷绕轴线且从电极组件从内到外的方向，每个阻挡层在第二弯折区17B2沿卷绕方向覆盖的圆周角度可以依次减小，例如，第三阻挡层1706在第二弯折区17B2沿卷绕方向覆盖的圆周角度小于第二阻挡层1705在第二弯折区17B2覆盖的圆周角度，例如，第三阻挡层1706在第二弯折区17B2沿卷绕方向覆盖的圆周角度为90°，第二阻挡层1705在第二弯折区17B2沿卷绕方向覆盖的圆周角度为180°。
本实施例中，第一阻挡层1704、第二阻挡层1705和第三阻挡层1706的功能、结构和分布方式等相关内容，均可以参考前述图1-10实施例所描述的阻挡层的相关内容，在此不再赘述。
如图20所示，为本申请另一实施例的一种电池单体的结构示意图。电池单体包括外壳181和容置于外壳181内的一个或多个电极组件182，外壳181包括壳体1811和盖板1812，壳体1811具有容纳腔，且壳体1811具有开口，即该平面不具有壳体壁而使得壳体1811内外相通，以便电极组件182可以收容于壳体1811的容纳腔内，盖板1812与壳体1811结合于壳体1811的开口处以形成中空腔体，电极组件182容置于外壳181内后，外壳181内充有电解液并密封。
壳体1811根据一个或多个电极组件182组合后的形状而定，例如，壳体1811可以为中空长方体或中空正方体或中空圆柱体。例如，当壳体1811为中空的长方体或正方体时，壳体1811的其中一个平面为开口面，即该平面不具有壳体壁而使得壳体1811内外相通；当壳体1811为中空的圆柱体时，壳体1811的其中一个圆形侧面为开口面，即该圆形侧面不具有壳体壁而使得壳体1811内外相通。
在本申请的另一实施例，壳体1811可由导电金属的材料或塑料制成，可选地，壳体1811由铝或铝合金制成。
电极组件182的结构可以参考前述图1-19实施例描述的电极组件的相关内容，在此不再赘述。
如图21所示，为本申请另一实施例的一种电池模组的结构示意图，电池模组19包括多个相互连接的电池单体191，其中，多个电池单体191之间可以串联或并联或混联，混联是指连接同时包括串联和并联，电池单体191的结构可以参考图20所对应实施例描述的电池单体，在此不再赘述。
如图22所示，为本申请另一实施例的一种电池的结构示意图，电池包括多个电池模组19和箱体，箱体包括下箱体20和上箱体30，多个电池模组19之间可以串联或并联或混联，下箱体20具有容纳腔，且下箱体20具有开口，以便连接后的多个电池模组19可以收容于下箱体20的容纳腔内，上箱体30与下箱体20结合于下箱体20的开口处以形成中空腔体，上箱体30与下箱体20结合后密封。
在本申请的另一实施例中，电池可以单独给用电装置供电，该电池可以称为电池包，例如，用于汽车的供电。
在本申请的另一实施例中，根据用电装置的用电需求，多个电池相互连接后组合成电池组，用于给用电装置供电。在本申请的另一实施例中，该电池组也有可以容纳于一个箱体中，并封装。
为使得描述简洁，下述实施例以用电装置包括电池为例进行描述。
在本申请的一实施例还提供一种用电装置，例如，用电装置可以为汽车，例如，新能源车，用电装置包括前述实施例描述的电池，其中，用电装置使用的电池可以如图22对应的实施例所描述的电池，在此不再赘述。
例如，如图23所示，为本申请另一实施例的一种用电装置的结构示意图，用电装置可以为汽车，汽车可以为燃油汽车、燃气汽车或新能源汽车，新能源汽车可以是纯电动汽车、混合动力汽车或增程式汽车等。汽车包括电池2101、控制器2102和马达2103。电池2101用于向控制器2102和马达2103供电，作为汽车的操作电源和驱动电源，例如，电池2101用于汽车的启动、导航和运行时的工作用电需求。例如，电池2101向控制器2102供电，控制器2102控制电池2101向马达2103供电，马达2103接收并使用电池2101的电力作为汽车的驱动电源，替代或部分地替代燃油或天然气为汽车提供驱动动力。
如图24所示，为本申请另一实施例的一种电极组件的制造方法的流程示意图，电极组件的制造方法包括如下内容。
步骤221，提供正极极片、负极极片以及阻挡层。
步骤222，将正极极片和负极极片经过卷绕或者层叠，并形成弯折区。
弯折区中具有阻挡层，其中，至少一部分阻挡层位于相邻正极极片和负极极片之间，用于阻挡从正极极片脱出的至少一部分离子嵌入负极极片的弯折区。
在本申请的另一实施例中，还提供用于隔开相邻正极极片和负极极片的隔离膜，将隔离膜、正极极片和负极极片一起卷绕或层叠。
在本申请的另一实施例中，在将隔离膜、正极极片和负极极片一起卷绕或层叠之前，将阻挡层置于正极极片或负极极片的一个或两个表面上。例如，将阻挡层粘贴或涂覆于正极极片或负极极片的一个或两个表面上。
通过本实施例制造方法制造出的电极组件的相关结构，可以参考前述图1-19对应的实施例描述的电极组件的相关内容，在此不再赘述。
如图25所示，为本申请的另一实施例一种电极组件的制造设备结构示意，电极组件的制造设备包括：第一提供装置231、第二提供装置232、第三提供装置233和组装装置234。
第一提供装置231，用于提供正极极片。
第二提供装置232，用于提供负极极片。
第三提供装置233，用于提供阻挡层。
组装装置234，用于将正极极片和负极极片卷绕或者层叠后形成弯折区。
其中，弯折区中具有阻挡层，其中，至少一部分阻挡层位于相邻正极极片和负极极片之间，用于阻挡从正极极片脱出的至少一部分离子嵌入负极极片的弯折区。
在本申请的另一实施例中，电极组件的制造设备还包括第四提供装置235，用于提供用于隔开相邻正极极片和负极极片的隔离膜，组装装置234用于将正极极片、负极极片以及隔离膜经过卷绕或者层叠后形成弯折区。
在本申请的另一实施例中，第三提供装置233为两个，两个第三提供装置233用于分别提供阻挡层，并将阻挡层粘贴或涂覆于正极极片或负极极片的两个表面。
通过本实施例制造设备制造出的电极组件的相关结构，可以参考前述图1-19对应的实施例描述的电极组件的相关内容，在此不再赘述。
综上，电池单体的电极组件包括的相邻的正极极片和负极极片之间设置阻挡层， 在充电时，弯折区的正极极片的正极活性物质层脱出的离子至少一部分被阻挡层阻挡，使得被阻挡层阻挡的离子不能嵌入与正极极片相邻的负极极片在弯折区的负极活性物质层，使得当负极极片发生负极活性物质脱落时，降低析锂的发生，提高电池单体的安全风险，提高电池单体使用寿命。
本领域的技术人员能够理解，尽管在此的一些实施例包括其它实施例中所包括的某些特征而不是其它特征，但是不同实施例的特征的组合意味着处于本申请的范围之内并且形成不同的实施例。例如，在权利要求书中，所要求保护的实施例的任意之一都可以以任意的组合方式来使用。
以上实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的精神和范围。

Claims (28)

  1. 一种电极组件，其中，包括：正极极片(1)和负极极片(2)，所述正极极片(1)和所述负极极片(2)经过卷绕或者层叠后形成弯折区(C)；
    所述弯折区(C)具有阻挡层(4)，其中，至少一部分所述阻挡层(4)位于相邻的所述正极极片(1)和所述负极极片(2)之间，用于阻挡从所述正极极片(1)脱出的至少一部分离子嵌入所述弯折区(C)的所述负极极片(2)。
  2. 如权利要求1所述的电极组件，其中，所述电极组件还包括用于隔离相邻的所述正极极片(1)和所述负极极片(2)的隔离膜(3)，所述正极极片(1)的一个表面或两个表面附接所述阻挡层(4)，和/或，所述负极极片(2)的一个表面或两个表面附接所述阻挡层(4)，和/或，所述隔离膜(3)的一个表面或两个表面附接所述阻挡层(4)。
  3. 如权利要求1所述的电极组件，其中，所述电极组件还包括用于隔离相邻的所述正极极片(1)和所述负极极片(2)的隔离膜(3)，所述阻挡层(4)独立于所述弯折区(C)相邻的所述正极极片(1)和所述隔离膜(3)之间，或者，所述阻挡层(4)独立于所述弯折区(C)相邻的所述负极极片(2)和所述隔离膜(3)之间。
  4. 如权利要求2或3所述的电极组件，其中，所述阻挡层(4)的孔隙率小于所述隔离膜(3)的孔隙率。
  5. 如权利要求1-4任一项所述的电极组件，其中，所述电极组件包括一个所述正极极片(1)和一个所述负极极片(2)，所述一个正极极片(1)和所述一个负极极片(2)压实后经过卷绕后形成一个卷绕结构，其中，所述弯折区(C)内至少最内侧的相邻所述正极极片(1)和所述负极极片(2)之间具有所述阻挡层(4)。
  6. 如权利要求5所述的电极组件，其中，所述弯折区(C)最内侧的极片为负极极片(2)。
  7. 如权利要求1-6任一项所述的电极组件，其中，所述阻挡层(4)为非连续的多个，所述非连续的多个阻挡层(4)沿弯折方向间隔分布，或者所述非连续的多个阻挡层(4)沿垂直于所述弯折方向的方向间隔分布。
  8. 如权利要求1-7任一项所述的电极组件，其中，所述阻挡层(4)的厚度为2-200微米；或5-100微米。
  9. 如权利要求1-8任一项所述的电极组件，其中，所述阻挡层(4)具有至少一个通孔。
  10. 如权利要求9所述的电极组件，其中，所述阻挡层(4)的孔隙率为10％-70％； 或20％-60％。
  11. 如权利要求9或10任一项所述的电极组件，其中，所述阻挡层(4)的厚度为A微米，所述阻挡层(4)的孔隙率为B，其中，A和B满足以下关系式：
    3.5微米≤A/B≤2000微米；或7微米≤A/B≤1000微米。
  12. 如权利要求1-10任一项所述的电极组件，其中，所述负极极片(2)的负极活性物质层沿垂直于弯折方向的两端均超出所述正极极片(1)的正极活性物质层的对应端。
  13. 如权利要求1-12任一项所述的电极组件，其中，所述阻挡层(4)沿垂直于弯折方向包括两端，所述阻挡层(4)的其中一端或两端超出所述正极极片(1)的正极活性物质层。
  14. 如权利要求1-12任一项所述的电极组件，其中，所述阻挡层(4)沿垂直于弯折方向包括两端，所述负极极片(2)的负极活性物质层超出所述阻挡层(4)的其中一端或两端。
  15. 如权利要求1-14任一项所述的电极组件，其中，所述阻挡层(4)与所述负极极片(2)的曲率最大的部位相对设置。
  16. 如权利要求1-15任一项所述的电极组件，其中，所述阻挡层(4)包括如下至少一种：无机氧化物、粘结剂和胶带。
  17. 如权利要求1-16任一项所述的电极组件，其中，所述阻挡层(4)沿弯折方向延伸的两端均位于所述弯折区。
  18. 如权利要求1-16任一项所述的电极组件，其中，所述电极组件具有与所述弯折区连接的平直区(P)；
    所述阻挡层(4)沿弯折方向延伸的一端位于所述平直区(P)，另一端位于所述弯折区(C)；或者，所述阻挡层(4)沿弯折方向延伸的两端均位于所述平直区(P)。
  19. 一种电池单体，其中，包括：壳体(1811)、盖板(1812)和至少一个如权利要求1-18任一项所述的电极组件(182)，其中，
    所述壳体(1811)具有容纳腔和开口，所述电极组件(182)容纳于所述容纳腔中；
    所述盖板(1812)用于封闭所述壳体(1811)的开口。
  20. 一种电池，其中，包括箱体和至少一个如权利要求19所述的电池单体，所述电池单体收容于所述箱体内。
  21. 一种电极组件的制造方法，其中，包括：
    提供正极极片、负极极片以及阻挡层；
    将所述正极极片和所述负极极片经过卷绕或者层叠，并形成弯折区，其中，所述弯折区中具有阻挡层，其中，至少一部分所述阻挡层位于相邻所述正极极片和所述负极极片之间，用于阻挡从所述正极极片脱出的至少一部分离子嵌入所述弯折区的所述负极极片。
  22. 如权利要求21的所述方法，其中，提供用于隔开相邻所述正极极片和所述负极极片的隔离膜，将所述隔离膜、所述正极极片和所述负极极片一起卷绕或层叠。
  23. 如权利要求22的所述方法，其中，在将所述隔离膜、所述正极极片和所述负极极片一起卷绕或层叠之前，所述方法还包括：
    将所述阻挡层置于所述正极极片或所述负极极片的一个或两个表面上。
  24. 如权利要求23的所述方法，其中，所述将所述阻挡层置于所述正极极片或负极极片的一个或两个表面上具体包括：
    将所述阻挡层粘贴或涂覆于所述正极极片或负极极片的一个或两个表面上。
  25. 一种电极组件的制造设备，其中，包括：
    第一提供装置，用于提供正极极片；
    第二提供装置，用于提供负极极片；
    第三提供装置，用于提供阻挡层；
    组装装置，用于将所述正极极片和所述负极极片卷绕或者层叠，并形成弯折区；
    其中，所述弯折区中具有阻挡层，其中，至少一部分所述阻挡层位于相邻所述正极极片和所述负极极片之间，用于阻挡从所述正极极片脱出的至少一部分离子嵌入所述弯折区的所述负极极片。
  26. 如权利要求25所述的制造设备，其中，还包括第四提供装置，用于提供用于隔开相邻所述正极极片和所述负极极片的隔离膜，所述组装装置还用于将所述正极极片、所述负极极片以及所述隔离膜经过卷绕或者层叠后形成所述弯折区。
  27. 如权利要求26所述的制造系统，其中，所述第三提供装置为两个，两个所述第三提供装置用于分别提供所述阻挡层，并将所述阻挡层粘贴或涂覆于所述正极极片或负极极片的两个表面。
  28. 一种用电装置，其中，所述用电装置被配置为接收从权利要求20所述的电池提供的电力。
PCT/CN2020/110628 2020-08-21 2020-08-21 电极组件、电池单体、电池及制造电极组件的方法和装置 WO2022036721A1 (zh)

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