WO2023004823A1 - 卷绕式电极组件、电池单体、电池及用电设备 - Google Patents

卷绕式电极组件、电池单体、电池及用电设备 Download PDF

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Publication number
WO2023004823A1
WO2023004823A1 PCT/CN2021/109909 CN2021109909W WO2023004823A1 WO 2023004823 A1 WO2023004823 A1 WO 2023004823A1 CN 2021109909 W CN2021109909 W CN 2021109909W WO 2023004823 A1 WO2023004823 A1 WO 2023004823A1
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Prior art keywords
winding
positive electrode
positive
section
electrode
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PCT/CN2021/109909
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English (en)
French (fr)
Inventor
喻鸿钢
上官会会
杜鑫鑫
唐代春
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 CN202180088631.1A priority Critical patent/CN116711122A/zh
Priority to PCT/CN2021/109909 priority patent/WO2023004823A1/zh
Priority to EP21951409.8A priority patent/EP4300701A1/en
Priority to KR1020237022885A priority patent/KR20230117418A/ko
Priority to JP2023540142A priority patent/JP2024502427A/ja
Publication of WO2023004823A1 publication Critical patent/WO2023004823A1/zh
Priority to US18/485,822 priority patent/US20240055646A1/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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H01M10/0431—Cells with wound or folded electrodes
    • 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
    • H01M10/04—Construction or manufacture in general
    • H01M10/0404—Machines for assembling batteries
    • H01M10/0409—Machines for assembling batteries for cells with wound electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • 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
    • 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
    • H01M50/247—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders specially adapted for portable devices, e.g. mobile phones, computers, hand tools or pacemakers
    • 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
    • H01M50/249—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders specially adapted for aircraft or vehicles, e.g. cars or trains
    • 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
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • 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
    • 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
    • H01M2220/30—Batteries in portable systems, e.g. mobile phone, laptop
    • 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 battery technology, and in particular, relates to a wound electrode assembly, a battery cell, a battery, an electrical device, and a manufacturing method and equipment for the battery cell.
  • Lithium deposition is one of the main factors affecting the electrical performance and safety performance of the battery. Once lithium deposition occurs in the battery, it will not only reduce the electrical performance of the battery, but also easily form dendrites and dendrites with the accumulation of lithium deposition. The crystal may pierce the diaphragm, causing a short circuit in the battery and causing a safety hazard.
  • Embodiments of the present application provide a wound-type electrode assembly, a battery cell, a battery, an electrical device, and a manufacturing method and equipment for the battery cell, so as to reduce the risk of lithium deposition in the electrode assembly.
  • an embodiment of the present application provides a wound electrode assembly, including a positive electrode sheet.
  • the positive electrode sheet includes a connected positive electrode winding start section without a positive electrode tab and a positive electrode winding extension section provided with the positive electrode tab.
  • the positive electrode winding initial section is wound at least once.
  • the positive electrode tab is not provided at the initial section of the positive electrode winding.
  • the initial section of the positive electrode winding does not have a tab to directly lead out the current at the initial section of the positive electrode winding, which is equivalent to Increase the internal resistance corresponding to the initial winding section of the positive electrode.
  • the charging polarization of the part with the large internal resistance of the positive electrode sheet will be greater than that of the small internal resistance part of the positive electrode sheet. Therefore, when fully charged, the positive electrode sheet's The part with small internal resistance reaches the upper limit voltage, but the initial section of the positive electrode winding without the positive electrode lug does not actually reach the upper limit voltage. Voltage, so that it is difficult for ions to detach from the initial section of the positive electrode winding, thereby reducing the number of ions detached from the initial section of the positive electrode winding, and reducing the possibility of lithium precipitation in the electrode assembly.
  • the length of the positive electrode winding start section accounts for 5%-30% of the total length of the positive electrode sheet.
  • the length of the initial section of the positive electrode winding accounts for 5%-30% of the total length of the positive electrode sheet.
  • the length of the initial section of the positive electrode winding is less than 5% of the total length, the inner section of the initial section of the positive electrode winding The resistance increase is not obvious, the voltage corresponding to the initial section of positive electrode winding cannot be significantly reduced, and the problem of lithium deposition at the bending part of the electrode assembly cannot be significantly improved.
  • the length of the initial section of positive electrode winding accounts for 30% of the total length of the positive electrode sheet, the temperature rise of the first positive electrode lug along the winding direction of the positive electrode sheet will be too large, causing other risks such as thermal runaway.
  • the length of the positive electrode winding start section accounts for 10%-25% of the total length of the positive electrode sheet.
  • the length of the initial section of positive electrode winding accounts for 10% to 25% of the total length of the positive electrode sheet, which can not only significantly improve the problem of lithium deposition in the electrode assembly, but also reduce the first positive electrode thickness of the positive electrode sheet along the winding direction. Risk of excessive temperature rise of tabs.
  • the length of the positive electrode winding start section accounts for 15%-20% of the total length of the positive electrode sheet.
  • the length of the initial winding section of the positive electrode accounts for 15% to 20% of the total length of the positive electrode sheet, which can not only significantly improve the problem of lithium deposition in the electrode assembly, but also reduce the first positive electrode thickness of the positive electrode sheet along the winding direction. Risk of excessive temperature rise of tabs.
  • the positive electrode winding extension section is provided with a plurality of positive electrode tabs, from the positive electrode winding start end to the positive electrode winding end, the first one of the positive electrode winding extension section The area of the positive tab is larger than that of the rest of the positive tabs of the positive winding extension.
  • the first positive electrode tab of the positive electrode winding extension section will bear the temperature rise caused by the positive electrode winding initial section, and the first positive electrode tab of the positive electrode winding extension section
  • the area of one positive electrode tab is larger than the area of the remaining positive electrode tabs of the positive electrode winding extension section, which can effectively reduce the temperature rise of the positive electrode winding initial section, and ensure the temperature rise of the positive electrode winding initial section and the positive electrode winding extension section as much as possible. consistency.
  • the areas of the plurality of positive electrode tabs gradually decrease.
  • the area of the plurality of positive electrode tabs gradually decreases, so that the multiple positive electrode tabs will not completely overlap, but in the width direction of the positive electrode tabs. Dislocation is provided to ensure that each positive tab has an exposed area, thereby improving the heat dissipation capability of the positive tab.
  • the wound electrode assembly further includes a negative electrode sheet, and the area of the positive electrode tab is larger than the area of the negative electrode tab of the negative electrode sheet.
  • the temperature rise of the positive electrode sheet will be greater than that of the negative electrode sheet, and the heat dissipation capacity of the positive electrode sheet is smaller than that of the negative electrode sheet.
  • the area is larger than the area of the negative electrode lug of the negative electrode sheet, which can effectively reduce the temperature rise of the positive electrode sheet and effectively improve the heat dissipation capacity of the positive electrode sheet.
  • the positive winding extension section includes a positive winding middle section and a positive winding ending section, and the positive winding middle section is connected to the positive winding starting section and the positive winding starting section. Between the winding ending sections of the positive electrode, the intermediate winding section of the positive electrode is wound at least once, and each layer of the intermediate winding section of the positive electrode is provided with a positive electrode lug.
  • a positive electrode lug is provided in the middle section of each layer of positive electrode winding in each circle, which can increase the internal resistance difference between the initial section of positive electrode winding and the middle section of positive electrode winding, so that the positive electrode winding can be enlarged.
  • the voltage difference between the initial section of the positive electrode winding and the middle section of the positive electrode winding increases the difficulty of ion detachment in the initial section of the positive electrode winding, and further reduces the risk of lithium precipitation at the bending part of the initial section of the positive electrode winding.
  • the positive winding extension section includes a positive winding middle section and a positive winding ending section, and the positive winding middle section is connected to the positive winding starting section and the positive winding starting section. Between the positive winding end sections, the positive winding end section is wound at least one turn, and each turn of the positive electrode winding end section is provided with a positive electrode lug, or the positive electrode winding end section is not provided with a Describe the positive pole ear.
  • the distance between the negative electrode winding end section and the positive electrode winding end section is relatively small compared to other The distance between the coil layers is large, which may easily cause the ions in the winding end of the positive electrode to fail to reach the winding end of the negative electrode, resulting in lithium precipitation.
  • a positive electrode lug is installed at the end of the positive winding of each circle or no positive electrode is set at the end of the positive winding. The tab makes it possible to increase the difficulty of ion detachment at the winding end of the positive electrode, thereby reducing the number of ions detached from the winding end of the positive electrode and reducing the risk of lithium precipitation in the electrode assembly.
  • the wound electrode assembly further includes a negative electrode sheet, and the number of positive electrode tabs of the positive electrode sheet is smaller than the number of negative electrode tabs of the negative electrode sheet.
  • the internal resistance of the negative electrode sheet is smaller than that of the positive electrode sheet, ensuring that the ion receiving ability of the negative electrode sheet can be better than that of the positive electrode, and can be more effectively improved. Analyze the lithium problem.
  • the positive electrode winding extension section includes a positive electrode winding middle section and a positive electrode winding end section;
  • the wound electrode assembly further includes a negative electrode sheet, and the negative electrode sheet includes The negative electrode winding initial section corresponding to the positive electrode winding initial section, the negative electrode winding intermediate section corresponding to the positive electrode winding intermediate section, and the negative electrode winding end section corresponding to the positive electrode winding ending section section;
  • the negative electrode winding initial section is wound at least one turn, and each layer of the negative electrode winding initial section of each turn is provided with a negative electrode tab;
  • the negative electrode winding middle section is wound Multiple turns, one negative pole lug is provided in the middle section of the negative winding of each circle; and/or, the winding ending section of the negative electrode is wound at least one turn, and one negative electrode is provided in the ending section of the negative winding winding of each circle Ear.
  • the positive electrode sheet of the innermost ring is arranged around the outer circumference of the negative electrode sheet of the innermost ring, and the length of the positive electrode sheet of the innermost ring along the winding direction is greater than the length of the negative electrode sheet of the innermost ring along the winding direction. Then the number of ions that can be detached from the positive electrode sheet of the innermost circle is greater than the number of ions that can be received by the negative electrode sheet of the innermost circle, which will easily lead to lithium precipitation, and each layer of each circle of the initial section of the negative electrode winding is provided with a negative electrode.
  • a negative electrode lug is provided in the middle section of the negative electrode winding of each circle, which can improve the ion receiving capacity of the middle section of the negative electrode winding and reduce the risk of lithium precipitation in the electrode assembly.
  • the distance between the winding ending section of the negative electrode and the winding ending section of the positive electrode is larger than that of other coil layers, which may easily cause the ions in the winding ending section of the positive electrode to fail to reach the winding ending section of the negative electrode, resulting in lithium precipitation.
  • a negative electrode lug is provided at the winding end section, so that the internal resistance of the negative electrode winding end section is small, which can improve the ion receiving capacity of the negative electrode winding middle section, and reduce the risk of lithium precipitation in the electrode assembly.
  • the initial winding section of the positive electrode is provided with a heat dissipation structure.
  • the internal resistance of the initial section of the positive electrode winding is larger than that of the case where the positive electrode tab is provided at the initial section of the positive electrode winding, then The temperature rise in the initial winding section of the positive electrode is relatively large, and the heat dissipation structure at the initial winding section of the positive electrode can improve the heat dissipation capacity of the initial winding section of the positive electrode.
  • an embodiment of the present application provides a battery cell, including a casing and the wound electrode assembly provided in the embodiment of the first aspect, the casing has an accommodation chamber; the wound electrode assembly is accommodated in the inside the chamber.
  • the positive electrode tab is not provided at the positive electrode winding initial section of the positive electrode sheet of the electrode assembly, which is equivalent to increasing the internal resistance corresponding to the positive electrode winding initial section, so that ions are separated from the positive electrode winding initial section The difficulty, thereby reducing the number of ions detached from the initial winding section of the positive electrode, and reducing the possibility of lithium precipitation in the electrode assembly.
  • the embodiment of the present application provides a battery, including a case and the battery cell provided in the embodiment of the second aspect.
  • the battery cells are accommodated in the case.
  • the positive electrode lug is not provided at the initial section of the positive electrode winding, it is equivalent to increasing the internal resistance corresponding to the initial section of the positive electrode winding, and the electrode assembly is less likely to decompose lithium, making the safety performance of the battery higher.
  • an embodiment of the present application provides an electric device, including the battery cell provided in some embodiments of the second aspect.
  • the embodiment of the present application provides a method for manufacturing a wound electrode assembly, including:
  • the positive electrode sheet comprising a connected positive electrode winding initial section without a positive electrode tab and a positive electrode winding extension section provided with a positive electrode tab;
  • the positive electrode sheet is wound and arranged, and the positive electrode winding start section is wound at least once.
  • the positive electrode tab is not provided at the initial section of the positive electrode winding.
  • the positive electrode sheet is wound to form an electrode assembly, it is equivalent to increasing the internal resistance corresponding to the initial section of the positive electrode winding, so that ions are wound from the positive electrode.
  • the difficulty of detachment of the initial section thereby reducing the number of ions detached from the initial section of the positive electrode winding, and reducing the possibility of lithium precipitation in the electrode assembly.
  • the embodiment of the present application provides a manufacturing equipment for a wound electrode assembly, including a providing device and an assembling device.
  • the providing device is configured to provide a positive electrode sheet, and the positive electrode sheet includes a connected positive electrode winding initial section without a positive electrode tab and a positive electrode winding extension section provided with a positive electrode tab; the assembly device is configured to The positive electrode sheet is wound and the positive electrode winding initial section is wound at least once.
  • the positive electrode tab is not provided at the initial section of the positive electrode winding.
  • the positive electrode sheet is wound to form an electrode assembly, it is equivalent to increasing the internal resistance corresponding to the initial section of the positive electrode winding, so that ions are wound from the positive electrode.
  • the difficulty of detachment of the initial section thereby reducing the number of ions detached from the initial section of the positive electrode winding, and reducing the possibility of lithium precipitation in the electrode assembly.
  • Fig. 1 is a schematic structural diagram of a vehicle provided by some embodiments of the present application.
  • Fig. 2 is a schematic structural diagram of a battery provided by some embodiments of the present application.
  • FIG. 3 is a schematic diagram of the connection of multiple battery cells through a confluence component provided by some embodiments of the present application;
  • Fig. 4 is an exploded view of a battery cell provided by some embodiments of the present application.
  • Fig. 5 is a schematic structural diagram of a wound electrode assembly provided by some embodiments of the present application.
  • Fig. 6 is a schematic structural diagram of a wound electrode assembly provided in some other embodiments of the present application.
  • Fig. 7 is a schematic structural view of a wound electrode assembly provided by another embodiment of the present application.
  • Fig. 8 is a schematic structural diagram of a wound electrode assembly provided in some further embodiments of the present application.
  • Fig. 9 is a schematic structural diagram of an electrode assembly provided in some further embodiments of the present application.
  • Fig. 10 is a schematic structural diagram of an electrode assembly provided in some other embodiments of the present application.
  • Figure 11 is a schematic diagram of the expanded structure of the positive electrode sheet provided by some embodiments of the present application.
  • Fig. 12 is a schematic diagram of the unfolded structure of the positive electrode sheet provided by other embodiments of the present application.
  • Fig. 13 is a schematic diagram of the unfolded structure of the positive electrode sheet provided by some further embodiments of the present application.
  • Figure 14 is a schematic structural diagram of the stacked arrangement of positive tabs provided by some facts of the present application.
  • Fig. 15 is the enlarged view of I place in Fig. 14;
  • Fig. 16 is a schematic structural view of the positive electrode sheet provided by some other embodiments of the present application.
  • Fig. 17 is a flowchart of a manufacturing method of a wound electrode assembly provided by some embodiments of the present application.
  • Fig. 18 is a flow chart of the manufacturing equipment of the wound electrode assembly provided by some embodiments of the present application.
  • Icons 1000-vehicle; 100-battery; 10-box; 11-accommodating space; 12-first part; 13-second part; 20-battery unit; 21-shell; 211-opening; 22-electrode assembly; 221-straight part; 222-bending part; 223-positive pole piece; 2231-positive pole lug; 2231a-first positive pole lug; 2231b-second positive pole lug; 2231c-third positive pole lug; 2232-positive pole Winding start section; 22321-radiation structure; 2233-positive winding extension; 22331-positive winding middle section; 22332-positive winding ending section; 2234-positive starting end; 2235-positive winding end; 2237-Second connection position; 224-Negative pole piece; 2241-Negative pole winding initial section; 2242-Negative pole winding middle section; 2243-Negative pole winding ending section; 2244b-the second negative pole tab; 2244c-the third negative
  • the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship that is usually placed when the product of the application is used, or the orientation or positional relationship of this application.
  • Orientations or positional relationships commonly understood by those skilled in the art are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood For the limitation of this application.
  • the terms “first”, “second”, “third”, etc. are only used for distinguishing descriptions, and should not be construed as indicating or implying relative importance.
  • “Plurality” in this application refers to two or more (including two).
  • the battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, which are not limited in the embodiments of the present application.
  • the battery cell can be in the form of a cylinder, a flat body, a cuboid or other shapes, which is not limited in this embodiment of the present application.
  • Battery cells are generally divided into three types according to packaging methods: cylindrical battery cells, square square battery cells and pouch battery cells, which are not limited in this embodiment of the present application.
  • the battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.
  • the battery mentioned in this application may include a battery module or a battery pack, and the like.
  • Batteries generally include a case for enclosing one or more battery cells. The box can prevent liquid or other foreign objects from affecting the charging or discharging of the battery cells.
  • the battery cell includes an electrode assembly and an electrolyte, and the electrode assembly is composed of a positive electrode sheet, a negative electrode sheet, and a separator.
  • a battery cell works primarily by moving metal ions between the positive and negative plates.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, the positive electrode active material layer is coated on the surface of the positive electrode current collector, and the positive electrode current collector that is not coated with the positive electrode active material layer protrudes from the positive electrode collector that has been coated with the positive electrode active material layer , the positive electrode current collector not coated with the positive electrode active material layer is used as the positive electrode tab.
  • the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium or lithium manganate.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, the negative electrode active material layer is coated on the surface of the negative electrode current collector, and the negative electrode current collector that is not coated with the negative electrode active material layer protrudes from the negative electrode collector that has been coated with the negative electrode active material layer , the negative electrode current collector not coated with the negative electrode active material layer is used as the negative electrode tab.
  • the material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon or silicon.
  • the number of positive pole tabs is multiple and stacked together, and the number of negative pole tabs is multiple and stacked together.
  • the material of the isolation film may be PP (polypropylene, polypropylene) or PE (polyethylene, polyethylene).
  • the electrode assembly has a wound structure.
  • Lithium deposition is one of the main factors affecting the electrical performance and safety performance of the battery. Once lithium deposition occurs, it will not only reduce the electrical performance of the battery, but also easily form dendrites with the accumulation of lithium deposition. The diaphragm may be pierced, causing a short circuit in the battery and causing a safety hazard. There are many reasons for lithium precipitation.
  • the inventors have found that, on the one hand, for the wound electrode assembly, at the bent portion, along the winding direction, the length of the positive active material on the side of the positive electrode sheet close to the winding center is greater than the length of the negative electrode sheet located on the inner side away from the winding direction.
  • the length of the negative electrode active material around the center side, the number of ions that can be separated from the positive electrode sheet is greater than the number of ions that the negative electrode sheet can receive, which easily leads to lithium precipitation; on the other hand, due to the manufacturing process of the wound electrode assembly.
  • the problem is that in the bent part of the wound electrode assembly, the gap between the positive electrode sheet and the negative electrode sheet of the inner ring is large, and lithium is easy to be deposited.
  • the internal resistance of the positive electrode sheet has an important impact on the ion detachment ability of the positive electrode sheet.
  • the smaller the internal resistance of the positive electrode the stronger the ion detachment ability on the positive electrode, the less difficult it is for ions to detach from the positive electrode, and the greater the risk of lithium precipitation.
  • the internal resistance of the negative electrode has an important impact on the ion receiving capacity of the negative electrode.
  • the embodiment of the present application provides a technical solution, by not setting the positive electrode lug at the positive electrode winding initial section of the positive electrode sheet, so that the internal resistance of the positive electrode winding initial section is increased, so that ions flow from the positive electrode coil It is more difficult to detach around the initial section, thereby reducing the number of ions detached from the initial section of the positive electrode winding, and reducing the possibility of lithium precipitation in the electrode assembly.
  • Electrical devices can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys and power tools, etc.
  • Vehicles can be fuel vehicles, gas vehicles or new energy vehicles, and new energy vehicles can be pure electric vehicles, hybrid vehicles or extended-range vehicles;
  • spacecraft include airplanes, rockets, space shuttles and spacecraft, etc.;
  • electric toys include fixed Type or mobile electric toys, such as game consoles, electric car toys, electric boat toys and electric airplane toys, etc.;
  • electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, for example, Electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, electric planers, and more.
  • the embodiment of the present application does not impose special limitations on the above electric equipment.
  • FIG. 1 is a schematic structural diagram of a vehicle 1000 provided by some embodiments of the present application.
  • the interior of the vehicle 1000 is provided with a battery 100 , and the battery 100 may be provided at the bottom, head or tail of the vehicle 1000 .
  • the battery 100 can be used for power supply of the vehicle 1000 , for example, the battery 100 can be used as an operating power source of the vehicle 1000 .
  • the vehicle 1000 may further include a controller 200 and a motor 300 , the controller 200 is used to control the battery 100 to supply power to the motor 300 , for example, for starting, navigating and running the vehicle 1000 .
  • the battery 100 can not only be used as an operating power source for the vehicle 1000 , but can also be used as a driving power source for the vehicle 1000 to provide driving power for the vehicle 1000 instead of or partially replacing fuel oil or natural gas.
  • FIG. 2 is a schematic structural diagram of a battery 100 provided by some embodiments of the present application.
  • the battery 100 includes a case 10 and battery cells 20 , and the battery cells 20 are accommodated in the case 10 .
  • the box body 10 is used to provide an accommodating space 11 for the battery cells 20 .
  • the box body 10 may include a first part 12 and a second part 13 , and the first part 12 and the second part 13 cover each other to define an accommodating space 11 for accommodating the battery cells 20 .
  • the connection between the first part 12 and the second part 13 can be sealed by a sealing member (not shown in the figure), and the sealing member can be a sealing ring, a sealant, or the like.
  • the first part 12 and the second part 13 can be in various shapes, such as cuboid, cylinder and so on.
  • the first part 12 can be a hollow structure with one side open, and the second part 13 can also be a hollow structure with one side open. Box 10.
  • the first part 12 may also be a hollow structure with one side open, the second part 13 may be a plate-like structure, and the second part 13 covers the open side of the first part 12 to form the box body 10 with the accommodation space 11 .
  • the battery 100 there may be one or a plurality of battery cells 20 . If there are multiple battery cells 20 , the multiple battery cells 20 may be connected in series, in parallel or in parallel.
  • the mixed connection means that the multiple battery cells 20 are both in series and in parallel.
  • a plurality of battery cells 20 can be directly connected in series, in parallel or mixed together, and then the whole composed of a plurality of battery cells 20 is housed in the box 10; of course, a plurality of battery cells 20 can also be connected in series first
  • a battery module is formed by connecting in parallel or in series, and multiple battery modules are connected in series or in parallel or in series to form a whole, and are accommodated in the box 10 .
  • the battery cell 20 may be in the form of a cylinder, a flat body, a cuboid or other shapes.
  • FIG. 2 exemplarily shows the case where the battery cell 20 is in the shape of a cube.
  • the battery 100 may further include a confluence part 30, and a plurality of battery cells 20 may be electrically connected through the confluence part 30, so as to realize series connection or parallel connection or connection of a plurality of battery cells 20. Combined.
  • the battery cell 20 may include a casing 21 , an electrode assembly 22 and an end cap assembly 23 .
  • the housing 21 has an opening 211 and a receiving cavity (not shown in the figure).
  • the electrode assembly 22 is accommodated in the containing chamber, and the end cap assembly 23 is used to cover the opening 211 .
  • the shell 21 can be in various shapes, such as cylinder, cuboid and so on.
  • the shape of the shell 21 can be determined according to the specific shape of the electrode assembly 22 .
  • the shell 21 can be a cylindrical structure; if the electrode assembly 22 is a rectangular parallelepiped, the shell 21 can be a rectangular parallelepiped.
  • FIG. 4 exemplarily shows the case that the casing 21 and the electrode assembly 22 are cuboids.
  • the housing 21 may also be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., which are not particularly limited in this embodiment of the present application.
  • the end cap assembly 23 is used to cover the opening 211 of the casing 21 to form a closed accommodating cavity (not shown in the figure), and the accommodating cavity is used to accommodate the electrode assembly 22 .
  • the accommodating space 11 is also used for accommodating electrolyte, such as electrolytic solution.
  • the end cover assembly 23 is used as a component for outputting the electric energy of the electrode assembly 22, and the electrode terminals in the end cover assembly 23 are used to be electrically connected to the electrode assembly 22, that is, the electrode terminals are electrically connected to the tabs of the electrode assembly 22, for example, the electrode terminals are connected to the electrode assembly 22.
  • the ears are connected through an adapter body (not shown in the figure), so as to realize the electrical connection between the electrode terminals and the pole ears.
  • the end cover assembly 23 can also be one, and then two electrode terminals can be arranged in the end cover assembly 23, and the two electrode terminals are respectively used to connect with the positive pole tab 2231 and the negative pole tab of the electrode assembly 22. 2244 are electrically connected, and the two electrode terminals in the end cover assembly 23 are positive electrode terminals and negative electrode terminals respectively.
  • the end cover assembly 23 may also be two, and the two end cover assemblies 23 cover the two sides of the casing 21 respectively. Opening 211.
  • the electrode terminal in one end cap assembly 23 may be a positive electrode terminal for electrical connection with the positive electrode tab 2231 of the electrode assembly 22; the electrode terminal in the other end cap assembly 23 may be a negative electrode terminal , for electrical connection with the negative electrode sheet 224 of the electrode assembly 22 .
  • the end cap assembly 23 may include an end cap 231 , a first electrode terminal 232 , a second electrode terminal 233 and a pressure relief mechanism 234 .
  • the first electrode terminal 232 is installed on the end cover 231 ; the second electrode terminal 233 is installed on the end cover 231 .
  • the pressure relief mechanism 234 is disposed on the end cover 231, and the pressure relief mechanism 234 is located between the first electrode terminal 232 and the second electrode terminal 233, and the pressure relief mechanism 234 is configured to trigger the battery when the internal pressure or temperature of the battery cell 20 reaches a threshold value. to release the internal pressure of the battery cell 20.
  • the end cap 231 in the end cap assembly 23 is used to cover the opening 211 of the housing 21 .
  • the end cap 231 can be in various shapes, such as circular, rectangular and so on.
  • the shape of the end cap 231 depends on the shape of the shell 21. If the shell 21 is a cylindrical structure, then a circular end cap 231 can be selected; if the shell 21 is a cuboid structure, a rectangular end cap 231 can be selected.
  • a cuboid wound electrode assembly 22 is used to introduce the related structure.
  • the electrode assembly 22 has a straight portion 221 and two opposite bent portions 222 .
  • the straight portion 221 is connected to the two bent portions 222 .
  • the electrode assembly 22 includes a positive electrode sheet 223 , and the positive electrode sheet 223 includes a connected positive electrode winding initial section 2232 without a positive electrode tab 2231 and a positive electrode winding extension section 2233 provided with a positive electrode tab 2231 .
  • the positive winding starting section 2232 is wound at least once.
  • Each section of positive electrode sheet 223 is equivalent to an internal resistance
  • each positive electrode tab 2231 is equivalent to connecting the corresponding internal resistances of two sections of positive electrode sheet 223 in parallel, and the internal resistance of the parallel circuit is smaller than that of the series circuit.
  • Each section of positive electrode sheet 223 can be understood as, if each circle of positive electrode sheet 223 has a tab, then each circle of positive electrode sheet 223 is equivalent to an internal resistance, or if each layer of each circle of positive electrode sheet 223 has a tab, each layer of positive plate 223 is equivalent to an internal resistance.
  • the positive electrode winding initial section 2232 is not provided with the positive electrode tab 2231, and the positive electrode winding extension section 2233 is provided with the positive electrode tab 2231.
  • the positive electrode winding initial section 2232 has no tab directly Deriving the current of the positive electrode winding initial section 2232 is equivalent to increasing the internal resistance corresponding to the positive electrode winding initial section 2232.
  • the part with a large internal resistance of the positive electrode sheet 223 will have a larger charging polarization than the positive electrode sheet.
  • 223 has a small internal resistance, so when fully charged, the small internal resistance of the positive electrode piece 223 reaches the upper limit voltage, while the positive winding start section 2232 without the positive electrode tab 2231 actually does not reach the upper limit voltage, which is different from the positive electrode.
  • the internal resistance of the positive electrode winding initial section 2232 is equivalent to reducing the voltage of the positive electrode winding initial section 2232, so that the difficulty of ion separation from the positive electrode winding initial section 2232 is reduced, thereby reducing the separation from the positive electrode winding initial section 2232
  • the number of ions in the electrode assembly 22 reduces the possibility of lithium precipitation.
  • the internal resistance of at least the positive electrode sheet 223 in the innermost circle is relatively large, which can improve the ion detachment ability of the positive electrode sheet 223 in the innermost circle and reduce bending.
  • the risk of lithium deposition at the folded portion 222 is reduced, thereby reducing the risk of lithium deposition in the electrode assembly 22.
  • the positive electrode sheet 223 has a positive electrode starting end 2234 and a positive electrode winding end 2235, the positive electrode starting end 2234 is the starting position of the positive electrode sheet 223 winding, the positive electrode starting end 2234 is located at the positive electrode winding starting section 2232, and the positive electrode winding end 2235 is the positive electrode At the termination position of the winding of the sheet 223 , the positive electrode winding end 2235 is located at the positive electrode winding extension section 2233 . After the winding of the positive electrode sheet 223 is completed, the positive electrode winding start section 2232 is closer to the winding central axis than the positive electrode winding extension section 2233 .
  • the positive winding starting section 2232 also has a first connection end, and the positive winding extension section 2233 also has a second connection end, and the positive winding starting section 2232 is connected through the second connection between the first connection end and the positive winding extension section 2233 The terminals are connected to form the first connection position 2236 of the positive electrode piece 223.
  • the positive electrode winding starting section 2232 is a part extending from the positive electrode starting end 2234 along the winding direction B, and can extend as far as the first positive electrode tab 2231 of the positive electrode sheet 223.
  • the positive electrode sheet 223 The whole of the first positive electrode tab 2231 is located in the positive winding extension section 2233 .
  • the first positive electrode tab 2231 of the positive electrode sheet 223 refers to the first positive electrode tab 2231 encountered along the winding direction B.
  • the first positive tab 2231 encountered by the positive sheet 223 along the winding direction B is defined as the first positive tab 2231a.
  • the positive winding extension section 2233 includes a positive winding middle section 22331 and a positive winding ending section 22332 , and the positive winding middle section 22331 is connected to the positive winding starting section 2232 and the positive winding Between the winding end sections 22332, the positive electrode winding intermediate section 22331 is wound at least one turn, and each layer of the positive electrode winding intermediate section 22331 is provided with a positive electrode tab 2231.
  • the first positive electrode tab 2231a is located in the middle section 22331 of the positive electrode winding.
  • Each layer of positive winding middle section 22331 of each circle is provided with a positive pole tab 2231, and each layer of positive pole winding middle section 22331 of each circle is provided with a positive pole tab 2231, which can increase the positive winding starting section 2232
  • the difference in internal resistance between the positive electrode winding middle section 22331 and the positive electrode winding initial section 2232 can increase the voltage difference between the positive electrode winding initial section 2232 and the positive electrode winding middle section 22331, thereby increasing the ion separation difficulty of the positive electrode winding initial section 2232 , to further reduce the risk of lithium deposition in the bending portion 222 of the positive electrode winding initial section 2232 .
  • the second connection end of the positive winding extension section 2233 is located in the positive winding middle section 22331.
  • the positive winding extension section 2233 also includes a third connection end and a fourth connection end.
  • the third connection end is located in the positive winding middle section 22331.
  • the four connection ends are located at the end section 22332 of the positive winding, and the middle section 22331 of the positive winding is connected to the first connection end of the starting section 2232 of the positive winding through the second connection end to form the first connection position 2236 of the positive electrode sheet 223.
  • the middle section 22331 is connected to the fourth connection end of the positive winding end section through the third connection end to form the second connection position 2237 of the positive electrode sheet 223 .
  • One turn of the positive electrode piece 223 refers to a 360° turn around the winding axis from the positive electrode starting end 2234 along the winding direction B.
  • a circle includes two layers, and the division of the two layers may be bounded by a thickness center plane P, which divides any circle of positive electrode sheets 223 into two layers on both sides thereof.
  • the winding axis of the electrode assembly 22 is parallel to the thickness center plane P, and the thickness direction C of the electrode assembly is perpendicular to the thickness center plane P.
  • One positive electrode tab 2231 is provided for each layer of the positive winding middle section 22331 of each circle.
  • the number of positive pole tabs 2231 of the positive winding middle section 22331 It is an even number. If the winding middle section 22331 of the positive electrode is wound to form an incomplete circle, the number of positive tabs 2231 of the middle section 22331 of the positive winding can be an odd number.
  • the positive pole tabs 2231 on the positive winding middle section 22331 except the first positive pole tab 2231a are defined as the second positive pole tab 2231b.
  • one positive pole lug 2231 may be provided in a circle of the positive winding middle section 22331 , and the pole lug is the first positive pole lug 2231 a.
  • the distance between the positive electrode winding end section 22332 and the corresponding negative electrode winding end section 2243 is larger than that of other circles, which may easily cause the ions in the winding end section 22332 of the positive electrode to fail to reach the winding end section 2243 of the negative electrode, resulting in lithium precipitation.
  • the positive winding extension section 2233 includes a positive winding middle section 22331 and a positive winding ending section 22332 , and the positive winding middle section 22331 is connected to the positive winding starting section 2232 Between the positive electrode winding end section 22332, the positive electrode winding end section 22332 is wound at least one turn, and each positive electrode winding end section 22332 is provided with a positive electrode tab 2231 (the third positive electrode tab 2231c in FIG.
  • the positive tab 2231 of the positive winding middle section 22331 is defined as the second positive tab 2231b
  • the positive tab 2231 of the positive winding ending section 22332 is defined as the third positive tab 2231c.
  • the positive electrode tab 2231 is not provided on the positive electrode winding end section 22332 . It can also increase the internal resistance of the winding end section 22332 of the positive electrode, thereby increasing the difficulty of ion detachment from the winding end section 22332 of the positive electrode and reducing the possibility of lithium deposition in the electrode assembly 22 .
  • the positive winding extension section 2233 includes a positive winding middle section 22331 and a positive winding ending section 22332;
  • the wound electrode assembly 22 also includes a negative electrode sheet 224, a negative electrode sheet 224 includes a negative electrode winding initial section 2241 corresponding to the positive electrode winding initial section 2232, a negative electrode winding intermediate section 2242 corresponding to the positive electrode winding intermediate section 22331, and a negative electrode winding section corresponding to the positive electrode winding end section 22332.
  • the negative electrode winding initial section 2241 is wound at least one turn, and each negative electrode winding initial section 2241 of each layer is provided with a negative electrode tab 2244 .
  • a negative electrode lug 2244 is arranged on each layer of each circle of the negative electrode winding initial section 2241, so that the internal resistance of the negative electrode winding ending section 2243 is reduced, the ion receiving capacity of the negative electrode winding initial section 2241 can be improved, and the electrode The risk of lithium deposition in the assembly 22, in other words, making at least the internal resistance of the innermost negative electrode sheet 224 smaller can improve the ion receiving capacity of the innermost negative electrode sheet 224 and reduce the risk of lithium deposition in the electrode assembly 22.
  • the negative electrode tab 2244 of the negative electrode winding initial section 2241 is defined as the first negative electrode tab 2244a
  • the negative electrode tab 2244 of the negative electrode winding middle section 2242 is defined as the second negative electrode tab 2244b
  • the negative electrode tab 2244 of the negative electrode winding end section 2243 is defined as the third negative electrode tab 2244c.
  • the positive winding initial section 2232 is set corresponding to the negative winding initial section 2241, which means that the positive winding initial section 2232 corresponds to the negative electrode sheet 224 inside it, and the positive winding ending section 22332 and the negative winding ending section 2243 are correspondingly arranged. That is, the negative electrode winding end section 2243 corresponds to the positive electrode sheet 223 inside it.
  • the negative electrode sheet 224 has a negative electrode starting end 2245 and a negative electrode winding end 2246, the negative electrode starting end 2245 is the starting position of the negative electrode sheet 224 winding, the negative electrode starting end 2245 is located at the negative electrode winding starting section 2241, and the negative electrode winding end 2246 is the negative electrode At the ending position of the winding of the sheet 224 , the negative electrode winding end 2246 is located at the negative electrode winding end section 2243 . After the negative electrode winding is completed, the negative electrode winding starting section 2241 is closer to the winding central axis than the negative electrode winding middle section 2242 and the negative electrode winding ending section 2243 .
  • the negative winding start section also has a fifth connection end
  • the negative winding end section 2243 also has a sixth connection end
  • the negative winding middle section 2242 also has a seventh connection end and an eighth connection section
  • the negative winding start section 2243 also has a sixth connection end.
  • the fifth connection end is connected to the seventh connection end of the negative electrode winding middle section 2242 to form the third connection position 2247 of the negative electrode sheet 224
  • the negative winding ending section is connected to the sixth connection end and the seventh connection end of the negative electrode winding middle section 2242.
  • the eight connection terminals are connected to form the fourth connection position 2248 of the negative electrode sheet 224 .
  • a negative electrode lug 2244 is provided for each turn of the negative electrode winding start section 2241 .
  • the negative electrode lug 2244 on the negative electrode winding initial section 2241 may also adopt other arrangements.
  • the first tab that appears on the electrode assembly 22 is the first negative pole tab 2244 located on the negative winding start section 2241 .
  • the negative electrode winding intermediate section 2242 is wound multiple times, and each negative electrode winding intermediate section 2242 is provided with a negative electrode tab 2244 (the second negative electrode tab 2244b in FIG. 9 ) , can improve the ion receiving capacity of the negative electrode winding middle section 2242, and reduce the risk of lithium deposition in the electrode assembly 22.
  • the negative electrode winding intermediate section 2242 may also have a negative electrode tab 2244 (the second negative electrode tab 2244b in FIG. 9 ) for each layer of each turn.
  • the negative electrode winding end section 2243 is wound at least one turn, and each negative electrode winding end section 2243 is provided with a negative electrode tab 2244 (the third negative electrode tab 2244c in FIG. 9 ), which can improve the ion receiving capacity of the negative electrode winding initial section 2241, and reduce the risk of lithium precipitation in the electrode assembly 22.
  • a negative electrode lug 2244 may also be provided on each layer of each turn of the negative winding end section 2243 .
  • the negative electrode winding initial section 2241 is wound at least one turn, and each negative electrode winding initial section 2241 of each layer is provided with a negative electrode tab 2244 (in FIG. 10 The first negative electrode tab 2244a).
  • the negative electrode winding intermediate section 2242 is wound at least one turn, and each negative electrode winding intermediate section 2242 is provided with a negative electrode tab 2244 (the second negative electrode tab 2244b in FIG. 10 ).
  • the negative electrode winding end section 2243 is wound at least one turn, and each layer of the negative electrode winding end section 2243 is provided with a negative electrode tab 2244 (the third negative electrode tab 2244c in FIG.
  • a negative electrode lug 2244 is provided on the negative electrode winding end section 2243 of the layer, so that the internal resistance of the negative electrode winding end section 2243 is small, the ion receiving capacity of the negative electrode winding middle section can be improved, and the risk of lithium deposition in the electrode assembly 22 is reduced.
  • the positive pole tab 2231 is not provided in the initial section 2232 of the positive pole winding, and one positive pole tab is provided for each layer of each circle of the positive pole winding middle section (the first positive pole tab 2231a and the second positive pole tab 2231b in FIG. 10 ) , the positive electrode winding end section 22332 is not provided with the positive electrode tab 2231 .
  • the electrode assembly 22 further includes a separator 225 for separating the positive electrode sheet 223 and the negative electrode sheet 224 to avoid direct contact between the positive electrode sheet 223 and the negative electrode sheet 224 , resulting in a short circuit.
  • the length of the positive electrode winding start section 2232 accounts for 5%-30% of the total length of the positive electrode sheet 223 .
  • the length of the positive electrode winding initial section 2232 is less than 5% of the total length, the internal resistance of the positive electrode winding initial section 2232 does not increase significantly, and the voltage corresponding to the positive electrode winding initial section 2232 cannot be significantly reduced, and cannot be significantly improved.
  • the bent portion 222 of the electrode assembly 22 has a problem of decomposing lithium.
  • the length of the positive electrode winding start section 2232 accounts for 30% of the total length of the positive electrode sheet 223, the temperature rise of the first positive electrode tab 2231 of the positive electrode sheet 223 along the winding direction B will be too large, causing thermal runaway and other problems. risk.
  • the total length of the positive electrode sheet 223 refers to the size of the portion of the positive electrode sheet 223 from the positive electrode starting end 2234 to the positive electrode winding end 2235 along the winding direction B.
  • the length of the positive electrode winding starting section 2232 refers to the size of the portion of the positive electrode sheet 223 from the positive electrode starting end 2234 to the first positive electrode tab 2231a along the winding direction B.
  • the length of the positive electrode winding start section 2232 accounts for 10% to 25% of the total length of the positive electrode sheet 223, which can not only significantly improve the problem of lithium deposition in the electrode assembly 22, but also reduce the length of the positive electrode sheet 223 along the winding direction. The risk of excessive temperature rise of the first positive tab 2231 of B.
  • the length of the positive electrode winding start section 2232 accounts for 15% to 20% of the total length of the positive electrode sheet 223, which can not only significantly improve the problem of lithium deposition in the electrode assembly 22, but also reduce the length of the positive electrode sheet 223 along the winding direction.
  • the risk of excessive temperature rise of the first positive tab 2231 of B It is also possible to make the positive electrode winding extension section 2233 provided with the positive electrode tab 2231 have an appropriate length, and an appropriate number of positive electrode tabs 2231 can be provided to ensure the flow area.
  • the positive winding extension 2233 is provided with a plurality of positive pole tabs 2231, from the positive winding start end to the positive winding end 2235, the area of the first positive pole tab 2231 of the positive winding extension 2233 The area of the remaining positive tab 2231 is larger than the positive winding extension 2233 .
  • the area of the first positive tab 2231a is greater than the area of the other positive tabs 2231 in the plurality of positive tabs 2231 except the first positive tab 2231a.
  • the first positive tab of the positive winding extension section 2233 will bear the temperature rise caused by the positive winding starting section 2232, and the area of the first positive tab 2231 of the positive winding extension section 2233 is larger than The area of the remaining positive tab 2231 of the positive winding extension section 2233 can effectively reduce the temperature rise of the positive winding starting section 2232, and ensure that the temperature rise of the positive winding starting section 2232 and the positive winding extension section 2233 are as consistent as possible. sex.
  • the remaining positive pole tabs 2231 refer to other positive pole tabs 2231 except the first positive pole tab 2231 .
  • the width dimension of the first positive pole tab 2231a is larger than the width dimension of the remaining positive pole tabs 2231, and the height dimension of the first positive pole tab 2231a is equal to the height dimension of the remaining positive pole tabs 2231 , so that the area of the first positive tab 2231a is larger than the area of the rest of the positive tabs 2231 .
  • the width dimension of the positive tab 2231 is the dimension along the winding direction B of the positive tab 2231
  • the height dimension of the positive tab 2231 is the dimension along the width direction of the positive tab 223 .
  • the height of the first positive tab 2231a is greater than the height of the rest of the positive tabs 2231, and the width of the first positive tab 2231a is equal to the width of the rest of the positive tabs 2231.
  • the area of the first positive tab 2231a is larger than the area of the rest of the positive tabs 2231 .
  • the width dimension of the first positive pole tab 2231a is larger than the width dimension of the remaining positive pole tabs 2231, and the height dimension of the first positive pole tab 2231a is greater than the height dimension of the remaining positive pole tabs 2231, so that Make the area of the first positive electrode tab 2231a larger than the area of the remaining positive electrode tabs 2231 .
  • the areas of the remaining positive tabs 2231 may be equal or unequal. In some embodiments, along the winding direction B, the areas of the remaining positive tabs 2231 gradually decrease. That is, from the starting end 2234 of the positive electrode to the winding end 2235 of the positive electrode (that is, along the winding direction B), the area of the plurality of positive electrode tabs 2231 gradually decreases. After such a positive electrode sheet 223 is wound, as shown in FIGS.
  • the positive pole tabs 2231 are stacked, because the area of the multiple positive pole tabs 2231 gradually decreases, so that the multiple positive pole tabs 2231 will not completely overlap, but have misalignments in the width direction of the positive pole tabs 2231, so that Each positive pole tab 2231 has an exposed area, thereby improving the heat dissipation capability of the positive pole tab 2231 .
  • the wound electrode assembly 22 further includes a negative electrode sheet 224 , and the area of the positive electrode tab 2231 is larger than the area of the negative electrode tab 2244 of the negative electrode sheet 224 . Because the positive electrode winding initial section 2232 is not provided with the positive pole lug 2231, the temperature rise of the positive electrode sheet 223 will be greater than the temperature rise of the negative electrode sheet 224, and the heat dissipation capacity of the positive electrode sheet 223 is less than that of the negative electrode sheet 224.
  • the area of the ear 2231 is larger than the area of the negative tab 2244 of the negative plate 224 , which can effectively reduce the temperature rise of the positive plate 223 and effectively improve the heat dissipation capacity of the positive plate 223 .
  • the positive winding initial section 2232 is provided with a heat dissipation structure 22321 . Since the positive electrode winding initial section 2232 is not provided with the positive electrode tab 2231, the internal resistance of the positive electrode winding initial section 2232 is larger than that of the case where the positive electrode winding initial section 2232 is provided with the positive electrode tab 2231, then The temperature rise of the positive electrode winding initial section 2232 is relatively large, and the heat dissipation structure 22321 provided in the positive electrode winding initial section 2232 can improve the heat dissipation capacity of the positive electrode winding initial section 2232 .
  • the heat dissipation structure 22321 is arranged on the positive electrode winding starting section 2232 and connected to at least one side in the width direction of the current collector coated with the active material layer on the positive electrode sheet 223.
  • the heat dissipation structure 22321 is a protrusion protruding from the active material layer to dissipate heat.
  • the height dimension of the structure 22321 is smaller than the height dimension of the positive pole ear 2231, the heat dissipation structure 22321 is not connected with the adapter body (not shown in the figure) and does not participate in overcurrent, only through the positive pole ear 2231 and the adapter body (not shown in the figure) shown) or the electrode terminals are electrically connected to draw out the current.
  • the negative electrode winding initial section 2241 can also be provided with a heat dissipation structure 22321 , and the structure of the heat dissipation structure 22321 of the negative electrode winding initial section 2241 can refer to the heat dissipation structure 22321 on the positive electrode winding initial section 2232 .
  • the wound electrode assembly 22 further includes a negative electrode sheet 224 , and the number of positive electrode tabs 2231 of the positive electrode sheet 223 is smaller than the number of negative electrode tabs 2244 of the negative electrode sheet 224 .
  • the total number of negative pole tabs 2244 is more than the total number of positive pole tabs 2231, then the internal resistance of the negative pole piece 224 is less than the internal resistance of the positive pole piece 223, ensuring that the ion receiving capacity of the negative pole piece 224 can be better than that of the positive pole. Analysis of the lithium problem.
  • the positive pole tab 2231 exceeds the positive pole tab 223 and the negative pole tab 2244 in the thickness direction C of the electrode assembly.
  • the thickness direction C of the electrode assembly exceeds the negative electrode sheet 224 , but this is not a limitation on the size of the positive electrode tab 2231 and the negative electrode tab 2244 in the thickness direction C of the electrode assembly.
  • the embodiment of the present application provides a method for manufacturing a wound electrode assembly 22, including:
  • Step S100 providing the positive electrode sheet 223, the positive electrode sheet 223 includes the connected positive electrode winding initial section 2232 without the positive electrode tab 2231 and the positive electrode winding extension section 2233 provided with the positive electrode tab 2231;
  • Step S200 winding the positive electrode sheet 223 and winding the positive electrode winding starting section 2232 at least once.
  • the positive electrode winding initial section 2232 is not provided with the positive electrode tab 2231.
  • the positive electrode sheet 223 is wound to form the electrode assembly 22, it is equivalent to increasing the internal resistance corresponding to the positive electrode winding initial section 2232, so that ions are wound from the positive electrode.
  • the difficulty of detachment from the initial section 2232 reduces the number of ions detached from the positive electrode winding initial section 2232 and reduces the possibility of lithium precipitation in the electrode assembly 22 .
  • the embodiment of the present application provides a wound electrode assembly manufacturing equipment 2000
  • the wound electrode assembly manufacturing equipment 2000 includes a providing device 2100 and an assembling device 2200 .
  • the providing device 2100 is configured to provide a positive electrode sheet 223, and the positive electrode sheet 223 includes a connected positive electrode winding start section 2232 without a positive electrode tab 2231 and a positive electrode winding extension section 2233 provided with a positive electrode tab 2231;
  • the assembly device 2200 is It is configured to wind the positive electrode sheet 223 and wind the positive electrode winding starting section 2232 at least once.
  • the positive electrode winding initial section 2232 is not provided with the positive electrode tab 2231.
  • the positive electrode sheet 223 is wound to form the electrode assembly 22, it is equivalent to increasing the internal resistance corresponding to the positive electrode winding initial section 2232, so that ions are wound from the positive electrode.
  • the difficulty of detachment from the initial section 2232 reduces the number of ions detached from the positive electrode winding initial section 2232 and reduces the possibility of lithium precipitation in the electrode assembly 22 .

Abstract

一种卷绕式电极组件（22）、电池单体（20）、电池（100）、用电设备、电池单体的制造方法及设备（2000），涉及电池技术领域。一种卷绕式电极组件（22），包括正极片（223）。正极片（223）包括相连的未设置正极极耳（2231）的正极卷绕起始段（2232）和设置有正极极耳（2231）的正极卷绕延伸段（2233）。正极卷绕起始段（2232）至少卷绕一圈。

Description

卷绕式电极组件、电池单体、电池及用电设备 技术领域
本申请涉及电池技术领域，具体而言，涉及一种卷绕式电极组件、电池单体、电池、用电设备、电池单体的制造方法及设备。
背景技术
目前，智能手机、平板电脑和电动汽车等的迅猛发展，锂离子电池的应用也日益广泛，因此对锂离子电池也提出了更高的要求。
人们在注重电池安全性能的同时还要求锂电池具有更好的电性能表现。而析锂即是影响电池的电性能和安全性能的主要因素的之一，电芯一旦发生析锂，不但会降低电池的电性能，而且随着析锂量的累加，容易形成枝晶，枝晶有可能会刺破隔膜，而引发电池内短路，造成安全隐患。
因此，如何有效避免或降低电池析锂的风险，成为目前亟待解决的技术问题。
发明内容
本申请实施例提供一种卷绕式电极组件、电池单体、电池、用电设备、电池单体的制造方法及设备，以降低电极组件析锂的风险。
第一方面，本申请实施例提供一种卷绕式电极组件，包括正极片。所述正极片包括相连的未设置正极极耳的正极卷绕起始段和设置有所述正极极耳的正极卷绕延伸段。所述正极卷绕起始段至少卷绕一圈。
上述技术方案中，正极卷绕起始段未设置正极极耳，当正极片卷绕形成电极组件后，正极卷绕起始段没有极耳直接将正极卷绕起始段的电流导出，相当于增大了正极卷绕起始段对应的内阻，在充电过程中，正极片的内阻大的部分充电极化会大于正极片的内阻小的部分，因此在满充时，正极片的内阻小的部分达上限电压，而未设置正极极耳的正极卷绕起始段实际未达到上限电压，与正极片的内阻小的部分相比，相当于降低正极卷绕起始段的电压，以使离子从正极卷绕起始段脱离的难度，从而减少从正极卷绕起始段脱离的离子的数量，降低电极组件析锂的可能性。
在本申请第一方面的一些实施例中，所述正极卷绕起始段的长度占所述正极片总长度的5％-30％。
上述技术方案中，正极卷绕起始段的长度占正极片总长度的5％-30％，当正极卷绕起始段的长度小于总长度的5％时，正极卷绕起始段的内阻增大不明显，不能明显降低正极卷绕起始段对应的电压，不能明显改善电极组件弯折部析锂的问题。当正极卷绕起始段的长度占比正极片总长度的30％时，会造成正极片沿卷绕方向的第一个正极极耳温升过大，引发热失控等其他风险。
在本申请第一方面的一些实施例中，所述正极卷绕起始段的长度占所述正极片总长度的10％～25％。
上述技术方案中，正极卷绕起始段的长度占正极片总长度的10％～25％，既能明显改善电极组件的析锂问题，又能降低正极片沿卷绕方向的第一个正极极耳温升过大的风险。
在本申请第一方面的一些实施例中，所述正极卷绕起始段的长度占所述正极片总长度的15％～20％。
上述技术方案中，正极卷绕起始段的长度占正极片总长度的15％～20％，既能明显改善电极组件的析锂问题，又能降低正极片沿卷绕方向的第一个正极极耳温升过大的风险。
在本申请第一方面的一些实施例中，所述正极卷绕延伸段设置有多个正极极耳，由正极卷绕起始端到正极卷绕末端，所述正极卷绕延伸段的第一个正极极耳的面积大于所述正极卷绕延伸段的其余正极极耳的面积。
上述技术方案中，由正极卷绕起始端到正极卷绕末端，正极卷绕延伸段的第一个正极极耳将承受正极卷绕起始段引起的温升，正极卷绕延伸段的第一个正极极耳的面积大于正极卷绕延伸段的其余正极极耳的面积能够有效降低正极卷绕起始段的温升，尽可能保证正极卷绕起始段和正极卷绕延伸段的温升的一致性。
在本申请第一方面的一些实施例中，由所述正极卷绕起始端到所述正极卷绕末端，多个所述正极极耳的面积逐渐减小。
上述技术方案中，由正极卷绕起始端到正极卷绕末端，多个正极极耳的面积逐渐减小，以使多个正极极耳不会完全重叠，而是在正极极耳的宽度方向上具有错位，以使保证每一个正极极耳都有外露的面积，从而提高正极极耳处的散热能力。
在本申请第一方面的一些实施例中，所述卷绕式电极组件还包括负极片，所述正极极耳的面积大于所述负极片的负极极耳的面积。
上述技术方案中，由于正极卷绕起始段未设置正极极耳，正极片的温升会大于负极片的温升，正极片的散热能力小于负极片的散热能力，正极片的正极极耳的面积大于负极片的负极极耳的面积，能够有效降低正极片的温升，有效提高正极片的散热能力。
在本申请第一方面的一些实施例中，所述正极卷绕延伸段包括正极卷绕中间段和正极卷绕收尾段，所述正极卷绕中间段连接于所述正极卷绕起始段和所述正极卷绕收尾段之间，所述正极卷绕中间段卷绕至少一圈，每一圈的每一层所述正极卷绕中间段设置一个正极极耳。
上述技术方案中，每一圈的每一层正极卷绕中间段设置一个正极极耳，可以增大正极卷绕起始段和正极卷绕中间段的内阻差值，从而可以加大正极卷绕起始段和正极卷绕中间段之间的电压差，进而增大正极卷绕起始段的离子脱离难度，进一步降低正极卷绕起始段在弯折部的析锂风险。
在本申请第一方面的一些实施例中，所述正极卷绕延伸段包括正极卷绕中间段和正极卷绕收尾段，所述正极卷绕中间段连接于所述正极卷绕起始段和所述正极卷绕收尾段之间，所述正极卷绕收尾段卷绕至少一圈，每一圈所述正极卷绕收尾段设置一个正极极耳，或所述正极卷绕收尾段未设置所述正极极耳。
上述技术方案中，由于负极卷绕收尾段和正极卷绕收尾段的束缚力较小，在电极组件反复膨胀、收缩后，负极卷绕收尾段和正极卷绕收尾段之间的距离相对其他的圈层的距离较大，容易导致正极卷绕收尾段的离子不能到达负极卷绕收尾段而导致析锂，每一圈正极卷绕收尾段设置一个正极极耳或者正极卷绕收尾段未设置正极极耳，使得能够增大正极卷绕收尾段离子脱离的难度，从而减少从正极卷绕收尾段脱离的离子的数量，降低电极组件析锂的风险。
在本申请第一方面的一些实施例中，所述卷绕式电极组件还包括负极片，所述正极片的正极极耳数量小于所述负极片的负极极耳数量。
上述技术方案中，负极极耳总数比正极极耳总数多，则负极片的内阻小于正极片的内阻，保证负极片的离子接收能力能够优于正极的离子脱出能力，能够更有效的改善析锂问题。
在本申请第一方面的一些实施例中，所述正极卷绕延伸段包括正极卷绕中间段和正极卷绕收尾段；所述卷绕式电极组件还包括负极片，所述负极片包括与所述正极卷绕起始段对应设置的负极卷绕起始段、与所述正极卷绕中间段对应设置的负极卷绕中间段和与所述正极卷绕收尾段对应设置的负极卷绕收尾段；所述负极卷绕起始段卷绕至少一圈，每一圈的每一层所述负极卷绕起始段设置一个负极极耳；和/或，所述负极卷绕中间段卷绕多圈，每一圈所述负极卷绕中间段设置一个负极极耳；和/或，所述负极卷绕收尾段卷绕至少一圈，每一圈所述负极卷绕收尾段设置一个负极极耳。
上述技术方案中，最内圈的正极片围设于最内圈的负极片的外周，则最内圈的正极片沿卷绕方向的长度大于最内圈的负极片沿卷绕方向的长度，则能够从最内圈的正极片脱离的离子的数量大于最内圈的负极片能够接收的离子的数量，容易导致析锂，负极卷绕起始段每一圈的每一层设置一个负极极耳，使得负极卷绕收尾段的内阻减小，能够提高负极卷绕起始段的离子接收能力，减低电极组件析锂的风险。每一圈负极卷绕中间段设置一个负极极耳，能够提高负极卷绕中间段的离子 接收能力，降低电极组件析锂的风险。负极卷绕收尾段和正极卷绕收尾段之间的距离相对其他的圈层的距离较大，容易导致正极卷绕收尾段的离子不能到达负极卷绕收尾段而导致析锂，每一圈负极卷绕收尾段设置一个负极极耳，使得负极卷绕收尾段的内阻较小，能够提高负极卷绕中间段的离子接收能力，减低电极组件析锂的风险。
在本申请第一方面的一些实施例中，所述正极卷绕起始段设有散热结构。
上述技术方案中，由于正极卷绕起始段未设置正极极耳，则正极卷绕起始段的内阻相较于正极卷绕起始段设置了正极极耳的情况内阻较大，则正极卷绕起始段的温升较大，正极卷绕起始段设置散热结构能够提高正极卷绕起始段的散热能力。
第二方面，本申请实施例提供一种电池单体，包括外壳和第一方面实施例提供的卷绕式电极组件，所述外壳具有容纳腔；所述卷绕式电极组件的容纳于所述容纳腔内。
上述技术方案中，电极组件的正极片的正极卷绕起始段未设置正极极耳，相当于增大了正极卷绕起始段对应的内阻，以使离子从正极卷绕起始段脱离的难度，从而减少从正极卷绕起始段脱离的离子的数量，降低电极组件析锂的可能性。
第三方面，本申请实施例提供一种电池，包括箱体和第二方面实施例提供的电池单体。所述电池单体的容纳于所述箱体内。
上述技术方案中，因正极卷绕起始段未设置正极极耳，相当于增大了正极卷绕起始段对应的内阻，则电极组件析锂的可能性较小，使得电池的安全性能更高。
第四方面，本申请实施例提供一种用电设备，包括第二方面的一些实施例提供的电池单体。
上述技术方案中，电池单体内部析锂的可能性较小，则电池单体的安全性较高，从而提高用电设备的用电安全。
第五方面，本申请实施例提供一种卷绕式电极组件的制造方法，包括：
提供正极片，所述正极片包括相连的未设置正极极耳的正极卷绕起始段和设置有正极极耳的正极卷绕延伸段；
将所述正极片卷绕设置并使所述正极卷绕起始段至少卷绕一圈。
上述技术方案中，正极卷绕起始段未设置正极极耳，当正极片卷绕形成电极组件后，相当于增大了正极卷绕起始段对应的内阻，以使离子从正极卷绕起始段脱离的难度，从而减少从正极卷绕起始段脱离的离子的数量，降低电极组件析锂的可能性。
第六方面，本申请实施例提供了一种卷绕式电极组件的制造设备，包括提供装置和组装装置。所述提供装置被配置为提供正极片，所述正极片包括相连的未设置正极极耳的正极卷绕起始段和设置有正极极耳的正极卷绕延伸段；所述组装装置被配置为将所述正极片卷绕并使所述正极卷绕起始段至少卷绕一圈。
上述技术方案中，正极卷绕起始段未设置正极极耳，当正极片卷绕形成电极组件后，相当于增大了正极卷绕起始段对应的内阻，以使离子从正极卷绕起始段脱离的难度，从而减少从正极卷绕起始段脱离的离子的数量，降低电极组件析锂的可能性。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对实施例中所需要使用的附图作简单地介绍，应当理解，以下附图仅示出了本申请的某些实施例，因此不应被看作是对范围的限定，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他相关的附图。
图1为本申请一些实施例提供的车辆的结构示意图；
图2为本申请一些实施例提供的电池的结构示意图；
图3为本申请一些实施例提供多个电池单体通过汇流部件连接示意图；
图4为本申请一些实施例提供的电池单体的爆炸图；
图5为本申请一些实施例提供的卷绕式电极组件的结构示意图；
图6为本申请又一些实施例提供的卷绕式电极组件的结构示意图；
图7为本申请另一些实施例提供的卷绕式电极组件的结构示意图；
图8为本申请再一些实施例提供的卷绕式电极组件的结构示意图；
图9为本申请再一些实施例提供的电极组件的结构示意图；
图10为本申请又一些实施例提供的电极组件的结构示意图；
图11为本申请一些实施例提供的正极片的展开的结构示意图；
图12为本申请另一些实施例提供的正极片的展开的结构示意图；
图13为本申请再一些实施例提供的正极片的展开的结构示意图；
图14为本申请一些事实提供的正极极耳层叠设置的结构示意图；
图15为图14中I处的放大图；
图16为本申请又一些实施例提供的正极片的结构示意图；
图17为本申请一些实施例提供的卷绕式电极组件的制造方法的流程图；
图18为本申请一些实施例提供的卷绕式电极组件的制造设备的流程图。
图标：1000-车辆；100-电池；10-箱体；11-容纳空间；12-第一部分；13-第二部分；20-电池单体；21-外壳；211-开口；22-电极组件；221-平直部；222-弯折部；223-正极片；2231-正极极耳；2231a-第一正极极耳；2231b-第二正极极耳；2231c-第三正极极耳；2232-正极卷绕起始段；22321-散热结构；2233-正极卷绕延伸段；22331-正极卷绕中间段；22332-正极卷绕收尾段；2234-正极起始端；2235-正极卷绕末端；2236-第一连接位置；2237-第二连接位置；224-负极片；2241-负极卷绕起始段；2242-负极卷绕中间段；2243-负极卷绕收尾段；2244-负极极耳；2244a-第一负极极耳；2244b-第二负极极耳；2244c-第三负极极耳；2245-负极起始端；2246-负极卷绕末端；2247-第三连接位置；2248-第四连接位置；225-隔离膜；23-端盖组件；231-端盖；232-第一电极端子；233-第二电极端子；234-泄压机构；30-汇流部件；200-控制器；300-马达；2000-卷绕式电极组件的制造设备；2100-提供装置；2200-组装装置；A-电极组件的宽度方向；B-卷绕方向；C-电极组件的厚度方向；P-厚度中心面。
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。通常在此处附图中描述和示出的本申请实施例的组件可以以各种不同的配置来布置和设计。
因此，以下对在附图中提供的本申请的实施例的详细描述并非旨在限制要求保护的本申请的范围，而是仅仅表示本申请的选定实施例。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他实施例，都属于本申请保护的范围。
需要说明的是，在不冲突的情况下，本申请中的实施例及实施例中的特征可以相互组合。
应注意到：相似的标号和字母在下面的附图中表示类似项，因此，一旦某一项在一个附图中被定义，则在随后的附图中不需要对其进行进一步定义和解释。
在本申请实施例的描述中，需要说明的是，指示方位或位置关系为基于附图所示的方位或位置关系，或者是该申请产品使用时惯常摆放的方位或位置关系，或者是本领域技术人员惯常理解的方位或位置关系，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，术语“第一”、“第二”、“第三”等仅用于区分描述，而不能理解为指示或暗示相对重要性。
本申请中出现的“多个”指的是两个以上(包括两个)。
本申请中，电池单体可以包括锂离子二次电池、锂离子一次电池、锂硫电池、钠锂离子电池、钠离子电池或镁离子电池等，本申请实施例对此并不限定。电池单体可呈圆柱体、扁平体、长方体或其它形状等，本申请实施例对此也不限定。电池单体一般按封装的方式分成三种：柱形电池单体、方体方形电池单体和软包电池单体，本申请实施例对此也不限定。
本申请的实施例所提到的电池是指包括一个或多个电池单体以提供更高的电压和容量的单一的物理模块。例如，本申请中所提到的电池可以包括电池模块或电池包等。电池一般包括用于封装一个或多个电池单体的箱体。箱体可以避免液体或其他异物影响电池单体的充电或放电。
电池单体包括电极组件和电解液，电极组件由正极片、负极片和隔离膜组成。电池单体主要依靠金属离子在正极片和负极片之间移动来工作。正极片包括正极集流体和正极活性物质层，正极活性物质层涂覆于正极集流体的表面，未涂敷正极活性物质层的正极集流体凸出于已涂覆正极活性物质层的正极集流体，未涂敷正极活性物质层的正极集流体作为正极极耳。以锂离子电池为例，正极集流体的材料可以为铝，正极活性物质可以为钴酸锂、磷酸铁锂、三元锂或锰酸锂等。负极片包括负极集流体和负极活性物质层，负极活性物质层涂覆于负极集流体的表面，未涂敷负极活性物质层的负极集流体凸出于已涂覆负极活性物质层的负极集流体，未涂敷负极活性物质层的负极集流体作为负极极耳。负极集流体的材料可以为铜，负极活性物质可以为碳或硅等。为了保证通过大电流而不发生熔断，正极极耳的数量为多个且层叠在一起，负极极耳的数量为多个且层叠在一起。隔离膜的材质可以为PP(polypropylene，聚丙烯)或PE(polyethylene，聚乙烯)等。在本申请实施例中，电极组件为卷绕式结构。
电池技术的发展要同时考虑多方面的设计因素，例如，能量密度、循环寿命、放电容量、充放电倍率等性能参数，另外，还需要考虑电池的安全性。而析锂即是影响电池的电性能和安全性能的主要因素的之一，一旦发生析锂，不但会降低电池的电性能，而且随着析锂量的累加，容易形成枝晶，枝晶有可能会刺破隔膜，而引发电池内短路，造成安全隐患。造成析锂的原因有很多。
发明人发现，一方面，对卷绕式电极组件而言，在弯折部，沿卷绕方向，正极片靠近卷绕中心一侧的正极活性物质的长度大于位于其内侧的负极片的远离卷绕中心一侧的负极活性物质的长度，则能够从正极片脱离的离子的数量大于负极片能够接收的离子的数量，容易导致析锂；另一方面，由于卷绕式电极组件的制造工艺的问题，在卷绕式电极组件的弯折部，内圈的正极片和负极片之间的间隙大，容易析锂。而正极片的内阻大小对正极片的离子脱离能力有重要的影响，正极片的内阻越大，正极片上离子脱离能力越弱，离子从正极片脱离的难度越大，析锂的风险越小，反之，正极片的内阻越小，正极片上离子脱离能力越强，离子从正极片脱离的难度越小，析锂的风险越大。负极片的内阻大小对负极片的离子接收能力有重要的影响，负极片的内阻越大，负极片离子接收能力越弱，析锂的风险越大，反之，负极片的内阻越小，负极片离子接收能力越强，析锂的风险越小。
鉴于此，本申请实施例提供一种技术方案，通过在正极片的正极卷绕起始段未设置正极极耳，从而使得正极卷绕起始段的内阻增大，以使离子从正极卷绕起始段脱离的难度增大，从而减少从正极卷绕起始段脱离的离子的数量，降低电极组件析锂的可能性。
本申请实施例描述的技术方案适用于电池以及使用电池的用电设备。
用电设备可以是车辆、手机、便携式设备、笔记本电脑、轮船、航天器、电动玩具和电动工具等等。车辆可以是燃油汽车、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；航天器包括飞机、火箭、航天飞机和宇宙飞船等等；电动玩具包括固定式或移动式的电动玩具，例如，游戏机、电动汽车玩具、电动轮船玩具和电动飞机玩具等等；电动工 具包括金属切削电动工具、研磨电动工具、装配电动工具和铁道用电动工具，例如，电钻、电动砂轮机、电动扳手、电动螺丝刀、电锤、冲击电钻、混凝土振动器和电刨等等。本申请实施例对上述用电设备不做特殊限制。
以下实施例为了方便说明，以用电设备为车辆为例进行说明。
请参照图1，图1为本申请一些实施例提供的车辆1000的结构示意图。车辆1000的内部设置有电池100，电池100可以设置在车辆1000的底部或头部或尾部。电池100可以用于车辆1000的供电，例如，电池100可以作为车辆1000的操作电源。
车辆1000还可以包括控制器200和马达300，控制器200用来控制电池100为马达300供电，例如，用于车辆1000的启动、导航和行驶时的工作用电需求。
在本申请一些实施例中，电池100不仅仅可以作为车辆1000的操作电源，还可以作为车辆1000的驱动电源，代替或部分地代替燃油或天然气为车辆1000提供驱动动力。
请参照图2，图2为本申请一些实施例提供的电池100的结构示意图。电池100包括箱体10和电池单体20，电池单体20收容于箱体10内。
箱体10用于为电池单体20提供容纳空间11。在一些实施例中，箱体10可以包括第一部分12和第二部分13，第一部分12与第二部分13相互盖合，以限定出用于容纳电池单体20的容纳空间11。当然，第一部分12与第二部分13的连接处可通过密封件(图未示出)来实现密封，密封件可以是密封圈、密封胶等。
第一部分12和第二部分13可以是多种形状，比如，长方体、圆柱体等。第一部分12可以是一侧开放的空心结构，第二部分13也可以是一侧开放的空心结构，第二部分13的开放侧盖合于第一部分12的开放侧，则形成具有容纳空间11的箱体10。当然，也可以是第一部分12为一侧开放的空心结构，第二部分13为板状结构，第二部分13盖合于第一部分12的开放侧，则形成具有容纳空间11的箱体10。
在电池100中，电池单体20可以是一个、也可以是多个。若电池单体20为多个，多个电池单体20之间可串联或并联或混联，混联是指多个电池单体20中既有串联又有并联。多个电池单体20之间可直接串联或并联或混联在一起，再将多个电池单体20构成的整体容纳于箱体10内；当然，也可以是多个电池单体20先串联或并联或混联组成电池模块，多个电池模块再串联或并联或混联形成一个整体，并容纳于箱体10内。电池单体20可呈圆柱体、扁平体、长方体或其它形状等。图2示例性的示出了电池单体20呈方体的情况。
请参照图3，在一些实施例中，电池100还可以包括汇流部件30，多个电池单体20之间可通过汇流部件30实现电连接，以实现多个电池单体20的串联或并联或混联。
请参照图4，电池单体20可以包括外壳21、电极组件22和端盖组件23。外壳21具有开口211和容纳腔(图中未示出)。电极组件22容纳于容纳腔内，端盖组件23用于封盖于开口211。
外壳21可以是多种形状，比如，圆柱体、长方体等。外壳21的形状可根据电极组件22的具体形状来确定。比如，若电极组件22为圆柱体结构，外壳21则可选用为圆柱体结构；若电极组件22为长方体结构，外壳21则可选用长方体结构。图4示例性的示出了外壳21和电极组件22为长方体的情况。
外壳21的材质也可以是多种，比如，铜、铁、铝、不锈钢、铝合金等，本申请实施例对此不作特殊限制。
端盖组件23用于封盖外壳21的开口211，以形成一密闭的容纳腔(图中未示出)，容纳腔用于容纳电极组件22。容纳空间11还用于容纳电解质，例如电解液。端盖组件23作为输出电极组件22的电能的部件，端盖组件23中的电极端子用于与电极组件22电连接，即电极端子与电极组件22的极耳电连接，比如，电极端子与极耳通过转接体(图中未示出)连接，以实现电极端子与极耳的电连接。
需要说明的，外壳21的开口211可以是一个，也可以是两个。若外壳21的开口211为一个，端盖组件23也可以为一个，端盖组件23中则可设置两个电极端子，两个电极端子分别用于与电极组件22正极极耳2231和负极极耳2244电连接，端盖组件23中的两个电极端子分别为正极电极端子和负极电极端子。若外壳21的开口211为两个，比如，两个开口211设置在外壳21相对的两侧，端盖组件23也可以为两个，两个端盖组件23分别盖合于外壳21的两个开口211处。在这种情况下，可以是一个端盖组件23中的电极端子为正极电极端子，用于与电极组件22的正极极耳2231电连接；另一个端盖组件23中的电极端子为负极电极端子，用于与电极组件22的负极片224电连接。
端盖组件23可以包括端盖231、第一电极端子232、第二电极端子233和泄压机构234。
第一电极端子232安装于端盖231；第二电极端子233安装于端盖231。泄压机构234设置于端盖231，泄压机构234位于第一电极端子232与第二电极端子233之间，泄压机构234被配置为在电池单体20的内部压力或温度达到阈值时致动以泄放电池单体20的内部的压力。
端盖组件23中的端盖231用于封盖外壳21的开口211。端盖231可以是多种形状，比如圆形、长方形等。端盖231的形状取决外壳21形状，若外壳21为圆柱体结构，则可选圆形端盖231；若外壳21为长方体结构，则可选用长方形端盖231。
本申请实施例以长方体的卷绕式电极组件22对相关结构进行介绍。
如图5所示，电极组件22具有平直部221和两个相对布置的弯折部222，沿电极组件的宽度方向A，平直部221的两端分别与两个弯折部222连接。
在一些实施例中，电极组件22包括正极片223，正极片223包括相连的未设置正极极耳2231的正极卷绕起始段2232和设置有正极极耳2231的正极卷绕延伸段2233。正极卷绕起始段2232至少卷绕一圈。
每段正极片223等效为一个内阻，而每个正极极耳2231相当于将两段正极片223对应的内阻并联，并联电路的内阻小于串联电路的内阻。每段正极片223可以理解为，如果每一圈正极片223出一个极耳，则每一圈正极片223等效为一个内阻，或者，如果每一圈正极片223的每一层出一个极耳，则每一层正极片223等效一个内阻。正极卷绕起始段2232未设置正极极耳2231，正极卷绕延伸段2233设置有正极极耳2231，当正极片223卷绕形成电极组件22后，正极卷绕起始段2232没有极耳直接将正极卷绕起始段2232的电流导出，相当于增大了正极卷绕起始段2232对应的内阻，在充电过程中，正极片223的内阻大的部分充电极化会大于正极片223的内阻小的部分，因此在满充时，正极片223的内阻小的部分到达上限电压，而未设置正极极耳2231的正极卷绕起始段2232实际未达到上限电压，与正极片223的内阻小的部分相比，相当于降低正极卷绕起始段2232的电压，以使离子从正极卷绕起始段2232脱离的难度，从而减少从正极卷绕起始段2232脱离的离子的数量，降低电极组件22析锂的可能性，换句话说，使得至少最内圈的正极片223的内阻较大，能够提高最内圈的正极片223的离子脱离能力，降低弯折部222处的析锂风险，从而降低电极组件22析锂的风险。
正极片223具有正极起始端2234和正极卷绕末端2235，正极起始端2234为正极片223卷绕的起始位置，正极起始端2234位于正极卷绕起始段2232，正极卷绕末端2235为正极片223的卷绕的终止位置，正极卷绕末端2235位于正极卷绕延伸段2233。当正极片223卷绕完成后，正极卷绕起始段2232相对于正极卷绕延伸段2233更靠近卷绕中心轴。正极卷绕起始段2232还具有第一连接端，正极卷绕延伸段2233还具有第二连接端，正极卷绕起始段2232通过第一连接端和正极卷绕延伸段2233的第二连接端连接，以形成正极片223的第一连接位置2236。
正极卷绕起始段2232为从正极起始端2234沿卷绕方向B延伸的一部分，最远可以延伸至正极片223的第一个正极极耳2231处，沿卷绕方向B，正极片223的第一个正极极耳2231的全部位于正极卷绕延伸段2233。沿卷绕方向B，正极片223的第一个正极极耳2231是指，沿卷绕方向B遇到的第一个正极极耳2231。为方便文中描述以及在图中示出，将正极片223沿卷绕方向B遇到的第一个正极极耳2231定义为第一正极极耳2231a。
请继续参见图5，在一些实施例中，正极卷绕延伸段2233包括正极卷绕中间段22331和 正极卷绕收尾段22332，正极卷绕中间段22331连接于正极卷绕起始段2232和正极卷绕收尾段22332之间，正极卷绕中间段22331卷绕至少一圈，每一圈的每一层正极卷绕中间段22331设置一个正极极耳2231。第一正极极耳2231a位于正极卷绕中间段22331。每一圈的每一层正极卷绕中间段22331设置一个正极极耳2231，每一圈的每一层正极卷绕中间段22331设置一个正极极耳2231，可以增大正极卷绕起始段2232和正极卷绕中间段22331的内阻差值，可以加大正极卷绕起始段2232和正极卷绕中间段22331之间的电压差，进而增大正极卷绕起始段2232的离子脱离难度，进一步降低正极卷绕起始段2232在弯折部222的析锂风险。
正极卷绕延伸段2233的第二连接端位于正极卷绕中间段22331，正极卷绕延伸段2233还包括第三连接端和第四连接端，第三连接端位于正极卷绕中间段22331，第四连接端位于正极卷绕收尾段22332，正极卷绕中间段22331通过第二连接端与正极卷绕起始段2232的第一连接端连接并形成正极片223的第一连接位置2236，正极卷绕中间段22331通过第三连接端与正卷绕收尾段的第四连接端连接并形成正极片223的第二连接位置2237。
正极片223的一圈是指，从正极起始端2234开始绕沿卷绕方向B绕卷绕轴线绕一个360°为一圈。一圈包括两层，两层的划分可以一厚度中心面P为界，厚度中心面P将任意一圈正极片223划分为位于其两侧的两层。电极组件22的卷绕轴线平行厚度中心面P，电极组件的厚度方向C垂直厚度中心面P。每一圈的每一层正极卷绕中间段22331设置一个正极极耳2231，若是正极卷绕中间段22331卷绕形成多个完整的圈，则正极卷绕中间段22331的正极极耳2231的数量为偶数个，若是正极卷绕中间段22331卷绕形成包括一个不完整的圈，则正极卷绕中间段22331的正极极耳2231的数量可以为奇数。为方便在图中示出，将正极卷绕中间段22331上除开第一正极极耳2231a的其他正极极耳2231定义为第二正极极耳2231b。
在一些实施例中，如图6所示，正极卷绕中间段22331可以一圈设置一个正极极耳2231，该极耳即为第一正极极耳2231a。
由于，负极卷绕收尾段2243和正极卷绕收尾段22332的束缚力较小，在电极组件反复膨胀、收缩后，正极卷绕收尾段22332和与之对应地负极卷绕收尾段2243之间的距离相对其他的圈层的距离较大，容易导致正极卷绕收尾段22332的离子不能到达负极卷绕收尾段2243而导致析锂。
基于此，请参见图6，在一些实施例中，正极卷绕延伸段2233包括正极卷绕中间段22331和正极卷绕收尾段22332，正极卷绕中间段22331连接于正极卷绕起始段2232和正极卷绕收尾段22332之间，正极卷绕收尾段22332卷绕至少一圈，每一圈正极卷绕收尾段22332设置一个正极极耳2231(图6中的第三正极极耳2231c)，以使正极卷绕收尾段22332的内阻较小，使得能够增大正极卷绕收尾段22332离子脱离的难度，从而减少从正极卷绕收尾段22332脱离的离子的数量，降低电极组件22析锂的风险。为方便在图中示出，定义正极卷绕中间段22331的正极极耳2231为第二正极极耳2231b，定义正极卷绕收尾段22332的正极极耳2231为第三正极极耳2231c。
当然，如图7所示，在一些实施例中，正极卷绕收尾段22332未设置正极极耳2231。也能增大正极卷绕收尾段22332的内阻，从而增加正极卷绕收尾段22332的离子脱离难度，降低电极组件22析锂的可能性。
基于此，如图8所示，在一些实施例中，正极卷绕延伸段2233包括正极卷绕中间段22331和正极卷绕收尾段22332；卷绕式电极组件22还包括负极片224，负极片224包括与正极卷绕起始段2232对应设置的负极卷绕起始段2241、与正极卷绕中间段22331对应设置的负极卷绕中间段2242和与正极卷绕收尾段22332对应设置的负极卷绕收尾段2243；负极卷绕起始段2241卷绕至少一圈，每一圈的每一层负极卷绕起始段2241设置一个负极极耳2244。负极卷绕起始段2241每一圈的每一层设置一个负极极耳2244，使得负极卷绕收尾段2243的内阻减小，能够提高负极卷绕起始段2241的离子接收能力，减低电极组件22析锂的风险，换句话说，使得至少最内圈的负极片224的内阻较小，能够提高最内圈的负极片224的离子接收能力，减低电极组件22析锂的风险。为方便在图中示出，将负极卷绕起始段2241的负极极耳2244定义为第一负极极耳2244a，将负极卷绕中间段2242的负极极耳2244定义第二负极极耳2244b，将负极卷绕收尾段2243的负极极耳2244定义为第三负极极耳2244c。
正极卷绕起始段2232与负极卷绕起始段2241对应设置是指，正极卷绕起始段2232与其内侧的负极片224对应，正极卷绕收尾段22332与负极卷绕收尾段2243对应设置是指，负极卷绕收尾段2243与其内侧的正极片223对应。
负极片224具有负极起始端2245和负极卷绕末端2246，负极起始端2245为负极片224卷绕的起始位置，负极起始端2245位于负极卷绕起始段2241，负极卷绕末端2246为负极片224的卷绕的终止位置，负极卷绕末端2246位于负极卷绕收尾段2243。当负极卷绕完成后，负极卷绕起始段2241相对于负极卷绕中间段2242和负极卷绕收尾段2243更靠近卷绕中心轴。负卷绕起始段还具有第五连接端，负极卷绕收尾段2243还具有第六连接端，负极卷绕中间段2242还具有第七连接端和第八连接段，负卷绕起始段通过第五连接端和负极卷绕中间段2242的第七连接端连接，以形成负极片224的第三连接位置2247，负卷绕收尾段通过第六连接端和负极卷绕中间段2242的第八连接端连接，以形成负极片224的第四连接位置2248。
如图9所示，在一些实施例中，负极卷绕起始段2241每一圈设置一个负极极耳2244。在其他实施例中，负极卷绕起始段2241上的负极极耳2244也可以采用其他的布置方式。
由于正卷绕起始段2232未设置正积极而2231，则沿卷绕方向B，电极组件22出现的第一个极耳是位于负极卷绕起始段2241上的第一个负极极耳2244。
请继续参见图9，在一些实施例中，负极卷绕中间段2242卷绕多圈，每一圈负极卷绕中间段2242设置一个负极极耳2244(图9中的第二负极极耳2244b)，能够提高负极卷绕中间段2242的离子接收能力，减低电极组件22析锂的风险。在另一些实施例中，负极卷绕中间段2242也可以是每一圈的每一层均设置一个负极极耳2244(图9中的第二负极极耳2244b)。
请继续参见图9，在一些实施例中，负极卷绕收尾段2243卷绕至少一圈，每一圈负极卷绕收尾段2243设置一个负极极耳2244(图9中的第三负极极耳2244c)，能够提高负极卷绕起始段2241的离子接收能力，减低电极组件22析锂的风险。在另一些实施例中，负极卷绕收尾段2243也可以是每一圈的每一层均设置一个负极极耳2244。
如图10所示，在一些实施例中，负极卷绕起始段2241卷绕至少一圈，每一圈的每一层负极卷绕起始段2241设置一个负极极耳2244(图10中的第一负极极耳2244a)。负极卷绕中间段2242卷绕至少一圈，每一圈负极卷绕中间段2242设置一个负极极耳2244(图10中的第二负极极耳2244b)。负极卷绕收尾段2243卷绕至少一圈，每一圈的每一层负极卷绕收尾段2243设置一个负极极耳2244(图10中的第三负极极耳2244c)，负极卷绕收尾段2243和正极卷绕收尾段22332之间的距离相对其他的圈层的距离较大，容易导致正极卷绕收尾段22332的离子不能到达负极卷绕收尾段2243而导致析锂，每一圈的每一层负极卷绕收尾段2243设置一个负极极耳2244，使得负极卷绕收尾段2243的内阻较小，能够提高负极卷绕中件段的离子接收能力，减低电极组件22析锂的风险。正极卷绕起始段2232未设置正极极耳2231，正极卷绕中间段的每一圈每一层设置一个正极极耳(图10中的第一正极极耳2231a和第二正极极耳2231b)，正极卷绕收尾段22332未设置正极极耳2231。
在一些实施例中，电极组件22还包括隔离膜225，隔离膜225用于分隔正极片223和负极片224，避免正极片223和负极片224直接接触，导致短路。
在一些实施例中，正极卷绕起始段2232的长度占正极片223总长度的5％-30％。当正极卷绕起始段2232的长度小于总长度的5％时，正极卷绕起始段2232的内阻增大不明显，不能明显降低正极卷绕起始段2232对应的电压，不能明显改善电极组件22弯折部222析锂的问题。当正极卷绕起始段2232的长度占比正极片223总长度的30％时，会造成正极片223沿卷绕方向B的第一个正极极耳2231温升过大，引发热失控等其他风险。
需要说明的是，正极片223总长度是指，沿卷绕方向B，正极片223从正极起始端2234至正极卷绕末端2235之间的部分的尺寸。正极卷绕起始段2232的长度是指，沿卷绕方向B，正极片223从正极起始端2234至第一正极极耳2231a之间的部分的尺寸。
在一些实施例中，正极卷绕起始段2232的长度占正极片223总长度的10％～25％，既能明显改善电极组件22的析锂问题，又能降低正极片223沿卷绕方向B的第一个正极极耳2231温升过 大的风险。
在一些实施例中，正极卷绕起始段2232的长度占正极片223总长度的15％～20％，既能明显改善电极组件22的析锂问题，又能降低正极片223沿卷绕方向B的第一个正极极耳2231温升过大的风险。还能使得设置有正极极耳2231的正极卷绕延伸段2233具有合适的长度，能够设置合适数量的正极极耳2231，以保证过流面积。
在一些实施例中，正极卷绕延伸段2233设置有多个正极极耳2231，由正极卷绕起始端到正极卷绕末端2235，正极卷绕延伸段2233的第一个正极极耳2231的面积大于正极卷绕延伸段2233的其余正极极耳2231的面积。换句话说，沿卷绕方向B，第一正极极耳2231a的面积大于多个正极极耳2231中除开第一正极极耳2231a之外的其他正极极耳2231的面积。沿卷绕方向B，正极卷绕延伸段2233的第一个正极极耳将承受正极卷绕起始段2232引起的温升，正极卷绕延伸段2233的第一个正极极耳2231的面积大于正极卷绕延伸段2233的其余正极极耳2231的面积能够有效降低正极卷绕起始段2232的温升，尽可能保证正极卷绕起始段2232和正极卷绕延伸段2233的温升的一致性。
其余正极极耳2231是指除开第一个正极极耳2231之外的其他正极极耳2231。
如图11所示，在一些实施例中，第一正极极耳2231a的宽度尺寸大于其余正极极耳2231的宽度尺寸，第一正极极耳2231a的高度尺寸与其余正极极耳2231的高度尺寸相等，以使第一正极极耳2231a的面积大于其余正极极耳2231的面积。正极极耳2231的宽度尺寸为正极极耳2231沿卷绕方向B上的尺寸，正极极耳2231的高度尺寸为沿正极片223的宽度方向上的尺寸。
如图12所示，在一些实施例中，第一正极极耳2231a的高度尺寸大于其余正极极耳2231高度尺寸，第一正极极耳2231a的宽度尺寸与其余正极极耳2231的宽度尺寸相等，以使第一正极极耳2231a的面积大于其余正极极耳2231的面积。
如图13所示，在一些实施例中，第一正极极耳2231a的宽度尺寸大于其余正极极耳2231的宽度尺寸，第一正极极耳2231a的高度尺寸大于其余正极极耳2231高度尺寸，以使第一正极极耳2231a的面积大于其余正极极耳2231的面积。
其余正极极耳2231的面积可以相等也可以不相等。在一些实施例中，沿卷绕方向B，其余正极极耳2231的面积逐渐减小。即由正极起始端2234到正极卷绕末端2235(即沿卷绕方向B)，多个正极极耳2231的面积逐渐减小，这样的正极片223卷绕后，如图14、图15所示，正极极耳2231层叠设置，由于多个正极极耳2231的面积逐渐减小，以使多个正极极耳2231不会完全重叠，而是在正极极耳2231的宽度方向上具有错位，以使每一个正极极耳2231都有外露的面积，从而提高正极极耳2231处的散热能力。
在一些实施例中，卷绕式电极组件22还包括负极片224，正极极耳2231的面积大于负极片224的负极极耳2244的面积。由于正极卷绕起始段2232未设置正极极耳2231，正极片223的温升会大于负极片224的温升，正极片223的散热能力小于负极片224的散热能力，正极片223的正极极耳2231的面积大于负极片224的负极极耳2244的面积，能够有效降低正极片223的温升，有效提高正极片223的散热能力。
如图16所示，在一些实施例中，正极卷绕起始段2232设有散热结构22321。由于正极卷绕起始段2232未设置正极极耳2231，则正极卷绕起始段2232的内阻相较于正极卷绕起始段2232设置了正极极耳2231的情况内阻较大，则正极卷绕起始段2232的温升较大，正极卷绕起始段2232设置散热结构22321能够提高正极卷绕起始段2232的散热能力。
散热结构22321设置于正极卷绕起始段2232并连接于正极片223涂覆有活性物质层的集流体的宽度方向的至少一侧，散热结构22321为凸出于活性物质层的凸起，散热结构22321的高度尺寸小于正极极耳2231的高度尺寸，散热结构22321不与转接体(图中为示出)连接且不参与过流，仅通过正极极耳2231与转接体(图中未示出)或电极端子电连接，以将电流引出。
在一些实施例中，负极卷绕起始段2241也可以设置散热结构22321，负极卷绕起始段2241的散热结构22321的结构可以参照正极卷绕起始段2232上的散热结构22321。
在一些实施例中，卷绕式电极组件22还包括负极片224，正极片223的正极极耳2231数量小于负极片224的负极极耳2244数量。负极极耳2244总数比正极极耳2231总数多，则负极片224的内阻小于正极片223的内阻，保证负极片224的离子接收能力能够优于正极的离子脱出能力，能够更有效的改善析锂问题。
需要说明的是，本申请实施例中，为方便在图中示出正极极耳2231和负极极耳2244，将正极极耳2231在电极组件的厚度方向C超出正极片223和负极极耳2244在电极组件的厚度方向C上超出负极片224，但这并非对正极极耳2231和负极极耳2244在电极组件的厚度方向C上的尺寸的限定。
如图17所示，本申请实施例提供一种卷绕式电极组件22的制造方法，包括：
步骤S100，提供正极片223，所正极片223包括相连的未设置正极极耳2231的正极卷绕起始段2232和设置有正极极耳2231的正极卷绕延伸段2233；
步骤S200，将正极片223卷绕设置并使正极卷绕起始段2232至少卷绕一圈。
正极卷绕起始段2232未设置正极极耳2231，当正极片223卷绕形成电极组件22后，相当于增大了正极卷绕起始段2232对应的内阻，以使离子从正极卷绕起始段2232脱离的难度，从而减少从正极卷绕起始段2232脱离的离子的数量，降低电极组件22析锂的可能性。
如图18所示，本申请实施例提供一种卷绕式电极组件的制造设备2000，卷绕式电极组件的制造设备2000包括提供装置2100和组装装置2200。提供装置2100被配置为提供正极片223，正极片223包括相连的未设置正极极耳2231的正极卷绕起始段2232和设置有正极极耳2231的正极卷绕延伸段2233；组装装置2200被配置为将正极片223卷绕并使正极卷绕起始段2232至少卷绕一圈。
正极卷绕起始段2232未设置正极极耳2231，当正极片223卷绕形成电极组件22后，相当于增大了正极卷绕起始段2232对应的内阻，以使离子从正极卷绕起始段2232脱离的难度，从而减少从正极卷绕起始段2232脱离的离子的数量，降低电极组件22析锂的可能性。
以上仅为本申请的优选实施例而已，并不用于限制本申请，对于本领域的技术人员来说，本申请可以有各种更改和变化。凡在本申请的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本申请的保护范围之内。

Claims (15)

  1. 一种卷绕式电极组件，其中，包括正极片；
    所述正极片包括相连的未设置正极极耳的正极卷绕起始段和设置有所述正极极耳的正极卷绕延伸段；
    所述正极卷绕起始段至少卷绕一圈。
  2. 根据权利要求1所述的卷绕式电极组件，其中，所述正极卷绕起始段的长度占所述正极片总长度的5％-30％；
    可选地，所述正极卷绕起始段的长度占所述正极片总长度的10％～25％；
    可选地，所述正极卷绕起始段的长度占所述正极片总长度的15％～20％。
  3. 根据权利要求1所述的卷绕式电极组件，其中，所述正极卷绕延伸段设置有多个正极极耳，由正极卷绕起始端到正极卷绕末端，所述正极卷绕延伸段的第一个正极极耳的面积大于所述正极卷绕延伸段的其余正极极耳的面积。
  4. 根据权利要求3所述的卷绕式电极组件，其中，由所述正极卷绕起始端到所述正极卷绕末端，多个所述正极极耳的面积逐渐减小。
  5. 根据权利要求1-4任一项所述的卷绕式电极组件，其中，所述卷绕式电极组件还包括负极片，所述正极极耳的面积大于所述负极片的负极极耳的面积。
  6. 根据权利要求1-5任一项所述的卷绕式电极组件，其中，所述正极卷绕延伸段包括正极卷绕中间段和正极卷绕收尾段，所述正极卷绕中间段连接于所述正极卷绕起始段和所述正极卷绕收尾段之间，所述正极卷绕中间段卷绕至少一圈，每一圈的每一层所述正极卷绕中间段设置一个正极极耳。
  7. 根据权利要求1-6任一项所述的卷绕式电极组件，其中，所述正极卷绕延伸段包括正极卷绕中间段和正极卷绕收尾段，所述正极卷绕中间段连接于所述正极卷绕起始段和所述正极卷绕收尾段之间，所述正极卷绕收尾段卷绕至少一圈，每一圈所述正极卷绕收尾段设置一个正极极耳，或所述正极卷绕收尾段未设置所述正极极耳。
  8. 根据权利要求1-7任一项所述的卷绕式电极组件，其中，所述卷绕式电极组件还包括负极片，所述正极片的正极极耳数量小于所述负极片的负极极耳数量。
  9. 根据权利要求1-8任一项所述的卷绕式电极组件，其中，所述正极卷绕延伸段包括正极卷绕中间段和正极卷绕收尾段；
    所述卷绕式电极组件还包括负极片，所述负极片包括与所述正极卷绕起始段对应设置的负极卷绕起始段、与所述正极卷绕中间段对应设置的负极卷绕中间段和与所述正极卷绕收尾段对应设置的负极卷绕收尾段；
    所述负极卷绕起始段卷绕至少一圈，每一圈的每一层所述负极卷绕起始段设置一个负极极耳；和/或，
    所述负极卷绕中间段卷绕多圈，每一圈所述负极卷绕中间段设置一个负极极耳；和/或，
    所述负极卷绕收尾段卷绕至少一圈，每一圈所述负极卷绕收尾段设置一个负极极耳。
  10. 根据权利要求1-9任一项所述的卷绕式电极组件，其中，所述正极卷绕起始段设有散热结构。
  11. 一种电池单体，其中，包括：
    外壳，具有容纳腔；以及
    根据权利要求1-10任一项所述的卷绕式电极组件，所述卷绕式电极组件的容纳于所述容纳腔内。
  12. 一种电池，其中，包括：
    箱体；
    根据权利要求11所述的电池单体，所述电池单体的容纳于所述箱体内。
  13. 一种用电设备，其中，包括根据权利要求11所述的电池单体。
  14. 一种卷绕式电极组件的制造方法，其中，包括：
    提供正极片，所述正极片包括相连的未设置正极极耳的正极卷绕起始段和设置有正极极耳的正极卷绕延伸段；
    将所述正极片卷绕设置并使所述正极卷绕起始段至少卷绕一圈。
  15. 一种卷绕式电极组件的制造设备，其中，包括：
    提供装置，被配置为提供正极片，所述正极片包括相连的未设置正极极耳的正极卷绕起始段和设置有正极极耳的正极卷绕延伸段；
    组装装置，被配置为将所述正极片卷绕并使所述正极卷绕起始段至少卷绕一圈。
PCT/CN2021/109909 2021-07-30 2021-07-30 卷绕式电极组件、电池单体、电池及用电设备 WO2023004823A1 (zh)

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