WO2022198682A1 - 电极组件、电池单体、电池及电极组件的制造方法和设备 - Google Patents

电极组件、电池单体、电池及电极组件的制造方法和设备 Download PDF

Info

Publication number
WO2022198682A1
WO2022198682A1 PCT/CN2021/083434 CN2021083434W WO2022198682A1 WO 2022198682 A1 WO2022198682 A1 WO 2022198682A1 CN 2021083434 W CN2021083434 W CN 2021083434W WO 2022198682 A1 WO2022198682 A1 WO 2022198682A1
Authority
WO
WIPO (PCT)
Prior art keywords
active material
positive electrode
negative electrode
main body
body portion
Prior art date
Application number
PCT/CN2021/083434
Other languages
English (en)
French (fr)
Inventor
许虎
任苗苗
李星
金海族
Original Assignee
宁德时代新能源科技股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to PCT/CN2021/083434 priority Critical patent/WO2022198682A1/zh
Priority to EP21809899.4A priority patent/EP4089769B1/en
Priority to CN202180006850.0A priority patent/CN115413379B/zh
Priority to US17/563,309 priority patent/US20220311056A1/en
Publication of WO2022198682A1 publication Critical patent/WO2022198682A1/zh

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—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
    • 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
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/103—Primary casings; Jackets or wrappings characterised by their shape or physical structure prismatic or rectangular
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M2010/4292—Aspects relating to capacity ratio of electrodes/electrolyte or anode/cathode
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present application relates to the field of battery technology, and in particular, to a method and equipment for manufacturing an electrode assembly, a battery cell, a battery, and an electrode assembly.
  • a rechargeable battery which can be called a secondary battery, refers to a battery that can continue to be used by activating the active material by charging after the battery is discharged.
  • Rechargeable batteries are widely used in electronic devices such as cell phones, laptops, battery cars, electric cars, electric planes, electric boats, electric toy cars, electric toy boats, electric toy planes, and power tools, among others.
  • the embodiments of the present application provide a method and device for manufacturing an electrode assembly, a battery cell, a battery, and an electrode assembly, which can effectively reduce lithium precipitation.
  • the embodiments of the present application provide an electrode assembly, comprising a negative electrode piece and a positive electrode piece, the negative electrode piece and the positive electrode piece are stacked and wound to form a winding structure with a flat area
  • the The negative electrode pole piece includes a negative electrode active material layer located in the flat area
  • the positive electrode pole piece includes a positive electrode active material layer located in the flat area and opposite to the negative electrode active material layer in the first direction, and the The first direction is perpendicular to the axial direction of the winding structure
  • the negative electrode active material layer includes a negative electrode main body portion and negative electrode edge portions located on both sides of the negative electrode main body portion in the axial direction, in the first direction At least part of the negative electrode main body part and at least part of the negative electrode edge part overlap with the positive electrode active material layer, and the active material capacity per unit area of the negative electrode main body part is larger than the active material per unit area of the negative electrode edge part and/or
  • the positive electrode active material layer includes a positive electrode main body portion and positive electrode edge portions located
  • the capacity of active material per unit area of the main body of the negative electrode is greater than the capacity of active material per unit area of the edge of the negative electrode, so that the main body of the negative electrode is less prone to lithium precipitation than the edge of the negative electrode.
  • the active material capacity per unit area of the edge of the negative electrode meets the setting requirements, that is, the active material capacity per unit area of the edge of the negative electrode reaches the first preset value, because the active material capacity per unit area of the main body of the negative electrode is greater than the active material capacity per unit area of the edge of the negative electrode
  • the material capacity that is, the capacity of the active material per unit area of the main body of the negative electrode is greater than the first preset value, which is equivalent to increasing the capacity of the active material per unit area of the main body of the negative electrode, increasing the CB value of the main body of the negative electrode, making it difficult for the main body of the negative electrode to be Lithium precipitation occurs, thereby reducing the risk of lithium precipitation in the middle region of the negative electrode active material layer in the first direction.
  • the active material capacity per unit area of the main body of the positive electrode is smaller than the active material capacity per unit area of the edge of the positive electrode, so that the part where the negative electrode active material layer and the positive electrode body part overlap is less prone to precipitation than the part where the negative electrode active material layer and the edge part of the negative electrode overlap. lithium.
  • the active material capacity per unit area of the edge of the positive electrode meets the setting requirements, that is, the active material capacity per unit area of the edge of the positive electrode reaches the second preset value, because the active material capacity per unit area of the main body of the positive electrode is smaller than the active material capacity per unit area of the edge of the positive electrode
  • the material capacity, that is, the active material capacity per unit area of the positive electrode main body is less than the second preset value, which is equivalent to reducing the active material capacity per unit area of the positive main body part and increasing the overlap of the negative electrode active material layer and the positive electrode main body.
  • the CB value makes the overlapping portion of the negative electrode active material layer and the positive electrode main body less prone to lithium deposition, thereby reducing the risk of lithium deposition in the middle region of the negative electrode active material layer in the first direction.
  • the negative electrode active material layer includes the negative electrode main body portion and the negative electrode edge portion
  • the positive electrode active material layer includes the positive electrode main body portion and the positive electrode edge portion; on the first side Upward, at least a portion of the negative electrode body portion overlaps at least a portion of the positive electrode body portion, and at least a portion of the negative electrode edge portion overlaps at least a portion of the positive electrode edge portion.
  • the capacity of active material per unit area of the main body of the negative electrode is greater than the capacity of active material per unit area of the edge portion of the negative electrode, the capacity of active material per unit area of the main body portion of the positive electrode is smaller than the capacity of active material per unit area of the edge portion of the positive electrode, in the first direction.
  • at least part of the main body of the negative electrode overlaps with at least part of the main body of the positive electrode, and the main body of the negative electrode is less prone to lithium precipitation, which further reduces the risk of lithium precipitation in the middle region of the negative electrode active material layer in the first direction.
  • the negative electrode body portion in the first direction, completely overlaps the positive electrode body portion.
  • the main body of the negative electrode and the main body of the positive electrode are completely overlapped, which can further reduce the risk of lithium precipitation in the main body of the negative electrode.
  • the gram capacity of the active material of the negative electrode body portion is greater than the gram capacity of the active material of the negative electrode edge portion.
  • the gram capacity of the active material in the main body of the negative electrode is greater than the gram capacity of the active material in the edge of the negative electrode, that is, by increasing the gram capacity of the active material in the main body of the negative electrode, the unit area of the main body of the negative electrode can be increased.
  • Active material capacity so that the active material capacity per unit area of the main body of the negative electrode is greater than the active material capacity per unit area of the edge portion of the negative electrode.
  • the ratio of the weight of the active material of the negative electrode body portion to the weight of the negative electrode body portion is greater than the ratio of the weight of the active material of the negative electrode edge portion to the weight of the negative electrode edge portion.
  • the ratio of the weight of the active material in the main body of the negative electrode to the weight of the main body of the negative electrode is greater than the ratio of the weight of the active material in the edge of the negative electrode to the weight of the edge of the negative electrode, that is, by increasing the activity of the main body of the negative electrode.
  • the specific gravity of the material can increase the active material capacity per unit area of the main body of the negative electrode, so that the active material capacity per unit area of the main body of the negative electrode is greater than the active material capacity per unit area of the edge of the negative electrode.
  • the gram capacity of the active material of the positive electrode body portion is less than the gram capacity of the active material of the positive electrode edge portion.
  • the gram capacity of the active material in the positive electrode main body is smaller than the gram capacity of the active material in the positive edge portion, that is to say, by reducing the gram capacity of the active material in the positive main body, the unit area of the positive main body can be reduced. Active material capacity, so that the active material capacity per unit area of the positive electrode main body portion is smaller than that of the positive electrode edge portion.
  • the positive electrode main body includes a first positive electrode coating and a second positive electrode coating layered in the first direction; the gram capacity of the active material of the first positive electrode coating is less than or equal to the positive electrode The gram capacity of the active material of the edge portion, the gram capacity of the active material of the second positive electrode coating is smaller than the gram capacity of the active material of the first positive electrode coating.
  • the main body of the positive electrode includes the first positive electrode coating and the second positive electrode coating layered in the first direction, because the gram capacity of the active material of the first positive electrode coating is less than or equal to the gram capacity of the active material in the edge portion of the positive electrode.
  • the gram capacity of the active material of the second positive electrode coating is smaller than the gram capacity of the active material of the first positive electrode coating, so that the gram capacity of the active material in the main body of the positive electrode is smaller than the gram capacity of the active material in the edge portion of the positive electrode, thereby making the positive electrode
  • the active material capacity per unit area of the main body portion is smaller than the active material capacity per unit area of the edge portion of the positive electrode.
  • the ratio of the weight of the active material of the positive body portion to the weight of the positive body portion is less than the ratio of the weight of the active material of the positive edge portion to the weight of the positive edge portion.
  • the ratio of the weight of the active material in the main body of the positive electrode to the weight of the main body of the positive electrode is smaller than the ratio of the weight of the active material in the edge of the positive electrode to the weight of the edge of the positive electrode, that is, by reducing the activity of the main body of the positive electrode.
  • the specific gravity of the material can reduce the active material capacity per unit area of the main body of the positive electrode, so that the active material capacity per unit area of the main body of the positive electrode is smaller than the active material capacity per unit area of the edge part of the positive electrode.
  • the thickness of the positive electrode body portion is smaller than the thickness of the positive electrode edge portion.
  • the active material capacity per unit area of the main body of the positive electrode can also be smaller than the active material capacity per unit area of the edge of the positive electrode.
  • the thickness of the positive electrode main body is smaller than the thickness of the positive edge portion, the thickness of the positive electrode sheet is relatively thin in the region where the positive electrode main body portion is located, which increases the threshold of resistance to expansion in this region to reduce the occurrence of lithium precipitation.
  • the negative electrode body portion and the negative electrode edge portion are continuously distributed in the axial direction.
  • the main part of the negative electrode and the edge of the negative electrode are continuously distributed in the axial direction, that is, the negative active material layer of the negative electrode pole piece is uninterrupted in the axial direction, which is beneficial to improve the capacity of the battery cell.
  • the positive electrode body portion and the positive electrode edge portion are continuously distributed in the axial direction.
  • the main body of the positive electrode and the edge of the positive electrode are continuously distributed in the axial direction, that is, the positive active material layer of the positive electrode sheet is uninterrupted in the axial direction, which is beneficial to improve the capacity of the battery cell.
  • an embodiment of the present application provides a battery cell, including a casing and the electrode assembly provided by any embodiment of the first aspect; the electrode assembly is accommodated in the casing.
  • an embodiment of the present application provides a battery, including a box body and the battery cell provided in any one of the embodiments of the second aspect, wherein the battery cell is accommodated in the box body.
  • an embodiment of the present application provides an electrical device, including the battery provided by any one of the embodiments of the third aspect.
  • an embodiment of the present application provides a method for manufacturing an electrode assembly, including: providing a negative pole piece and a positive pole piece; stacking and winding the negative pole piece and the positive pole piece to form a winding structure; wherein , the winding structure has a flat area, the negative electrode pole piece includes a negative electrode active material layer located in the flat area, and the positive electrode pole piece includes a negative electrode active material layer located in the flat area and adjacent to the negative electrode active material layer.
  • the positive electrode active material layer is oppositely arranged in a first direction, the first direction is perpendicular to the axial direction of the winding structure; the negative electrode active material layer includes a negative electrode main body part and two parts located in the negative electrode main body part in the axial direction.
  • the negative electrode main body part and at least part of the negative electrode edge part overlap with the positive electrode active material layer, and the active material per unit area of the negative electrode main body part is active.
  • the material capacity is greater than the active material capacity per unit area of the negative electrode edge portion; and/or, the positive electrode active material layer includes a positive electrode main body portion and positive electrode edge portions located on both sides of the positive electrode main body portion in the axial direction, where In the first direction, at least part of the positive electrode main body part and at least part of the positive electrode edge part overlap with the negative electrode active material layer, and the active material capacity per unit area of the positive electrode main body part is smaller than that of the positive electrode edge part The active material capacity per unit area.
  • the embodiments of the present application also provide a manufacturing equipment for an electrode assembly, including: providing a device for providing a positive pole piece and a negative pole piece; an assembling device for assembling the negative pole piece and the positive pole piece Sheets are stacked and rolled to form a rolled structure; wherein, the rolled structure has a flat area, the negative electrode sheet includes a negative electrode active material layer located in the flat area, and the positive electrode sheet includes a layer located in the flat area.
  • the negative electrode active material layer includes a negative electrode main body part and a The negative electrode edge portions located on both sides of the negative electrode main body portion in the axial direction, in the first direction, at least part of the negative electrode main body portion and at least part of the negative electrode edge portion are both connected to the positive electrode active material layer.
  • the active material capacity per unit area of the negative electrode main body is greater than the active material capacity per unit area of the negative electrode edge portion;
  • the positive electrode edge portions on both sides of the positive electrode portion, in the first direction, at least part of the positive electrode main body portion and at least part of the positive electrode edge portion both overlap with the negative electrode active material layer, and the positive electrode main body portion is overlapped with the negative electrode active material layer.
  • the active material capacity per unit area is smaller than the active material capacity per unit area of the edge portion of the positive electrode.
  • FIG. 1 is a schematic structural diagram of a vehicle provided by some embodiments of the present application.
  • FIG. 2 is an exploded view of a battery provided by some embodiments of the present application.
  • FIG. 3 is a schematic structural diagram of a battery module 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 an electrode assembly provided by some embodiments of the present application.
  • FIG. 6 is a partial view of the positive pole piece, the separator and the negative pole piece shown in FIG. 5 after unfolding;
  • FIG. 7 is an A-A cross-sectional view of the electrode assembly shown in FIG. 5;
  • FIG. 8 is a partial cross-sectional view of an electrode assembly provided by some embodiments of the present application.
  • FIG. 9 is a partial cross-sectional view of an electrode assembly provided by further embodiments of the present application.
  • FIG. 10 is a partial cross-sectional view of an electrode assembly provided by further embodiments of the present application.
  • FIG. 11 is a flowchart of a method for manufacturing an electrode assembly provided by some embodiments of the present application.
  • FIG. 12 is a flowchart of a method for manufacturing an electrode assembly provided by further embodiments of the present application.
  • FIG. 13 is a schematic block diagram of a manufacturing apparatus of an electrode assembly provided by some embodiments of the present application.
  • the terms “installed”, “connected”, “connected” and “attached” should be understood in a broad sense, for example, it may be a fixed connection, It can also be a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be internal communication between two components.
  • installed should be understood in a broad sense, for example, it may be a fixed connection, It can also be a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be internal communication between two components.
  • plural 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, etc., which are not limited in the embodiments of the present application.
  • the battery cell may be in the form of a cylinder, a flat body, a rectangular parallelepiped, or other shapes, which are not limited in the embodiments of the present application.
  • the battery cells are generally divided into three types according to the packaging method: cylindrical battery cells, square battery cells, and soft-pack battery cells, which are not limited in the embodiments 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 batteries mentioned in this application may include battery modules or battery packs, and the like.
  • Batteries typically include a case for enclosing one or more battery cells. The box can prevent liquids 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.
  • the battery cell mainly relies on the movement of metal ions between the positive and negative plates to work.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode active material body.
  • the positive electrode active material body is coated on the surface of the positive electrode current collector, and the positive electrode current collector without the positive electrode active material body protrudes from the positive electrode current collector that has been coated with the positive electrode active material body. , the positive electrode current collector without the positive electrode active material body 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 cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganate.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material body, the negative electrode active material body is coated on the surface of the negative electrode current collector, and the negative electrode current collector without the negative electrode active material body protrudes from the negative electrode current collector that has been coated with the negative electrode active material body. , the negative electrode current collector without the negative electrode active material body is used as the negative electrode tab.
  • the material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon.
  • the number of positive tabs is multiple and stacked together, and the number of negative tabs is multiple and stacked together.
  • the material of the separator can be PP (polypropylene, polypropylene) or PE (polyethylene, polyethylene), and the like.
  • the electrode assembly may be a wound structure or a laminated structure, and the embodiment of the present application is not limited thereto.
  • lithium-ion batteries For lithium-ion batteries, during charging, lithium ions are detached from the positive electrode and inserted into the negative electrode; during discharge, lithium ions are detached from the negative electrode and inserted into the positive electrode.
  • some abnormal conditions may occur, which may lead to lithium precipitation, such as insufficient space for lithium insertion in the negative electrode, excessive lithium ion migration resistance, and lithium ions are detached from the positive electrode too quickly but cannot be embedded in the negative electrode in an equal amount.
  • the lithium ions that cannot be embedded in the negative electrode can only obtain electrons on the surface of the negative electrode, thereby forming the phenomenon of lithium element, that is, the phenomenon of lithium precipitation.
  • an embodiment of the present application provides an electrode assembly, including a negative electrode piece and a positive electrode piece, the negative electrode piece and the positive electrode piece are stacked and wound to form a winding structure with a flat area, and the negative electrode piece includes a flat
  • the negative electrode active material layer in the region, the positive electrode sheet includes a positive electrode active material layer located in the flat region and opposite to the negative electrode active material layer in a first direction, the first direction being perpendicular to the axial direction of the winding structure.
  • the negative electrode active material layer includes a negative electrode main body portion and negative electrode edge portions located on both sides of the negative electrode main body portion in the axial direction.
  • the active material capacity per unit area of the negative electrode main body portion is greater than the unit area active material capacity of the negative electrode edge portion; and/or, the positive electrode active material layer includes a positive electrode main body portion and a positive electrode edge portion located on both sides of the positive electrode main body portion in the axial direction. In the first direction, at least part of the positive electrode main body part and at least part of the positive electrode edge part overlap with the negative electrode active material layer, and the active material capacity per unit area of the positive electrode main body part is smaller than the active material capacity per unit area of the positive electrode edge part.
  • the electrode assembly of this structure can effectively reduce the risk of lithium precipitation and improve the safety of the battery.
  • Electrical equipment can be vehicles, mobile phones, portable devices, notebook computers, ships, spacecraft, electric toys and power tools, and so on.
  • 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, etc.
  • spacecraft include airplanes, rockets, space shuttles, spacecraft, etc.
  • electric toys include fixed Electric toys that are portable or mobile, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc.
  • electric tools include metal cutting power tools, grinding power tools, assembling power tools and railway power tools, such as, Electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, electric impact drills, concrete vibrators and electric planers, etc.
  • the embodiments of the present application do not impose special restrictions on the above-mentioned electrical equipment.
  • the electric device is a vehicle as an example for description.
  • FIG. 1 is a schematic structural diagram of a vehicle 1000 according to some embodiments of the present application.
  • a battery 100 is disposed inside the vehicle 1000 , and the battery 100 may be disposed at the bottom, head or tail of the vehicle 1000 .
  • the battery 100 may be used for power supply of the vehicle 1000 , for example, the battery 100 may be used as an operation power source of the vehicle 1000 .
  • the vehicle 1000 may also include a controller 200 and a motor 300 for controlling the battery 100 to supply power to the motor 300 , eg, for starting, navigating, and running the vehicle 1000 for work power requirements.
  • the battery 100 can not only be used as the operating power source of the vehicle 1000 , but also can be used as the driving power source of the vehicle 1000 to provide driving power for the vehicle 1000 instead of or partially instead of fuel or natural gas.
  • FIG. 2 is an exploded view of a battery 100 provided by some embodiments of the application.
  • the battery 100 includes a case 10 and a battery cell 20 (not shown in FIG. 2 ), and the battery cell 20 is accommodated in the case 10 .
  • the case 10 is used for accommodating the battery cells 20 , and the case 10 may have various structures.
  • the case 10 may include a first part 11 and a second part 12 , the first part 11 and the second part 12 are mutually covered, and the first part 11 and the second part 12 together define a space for accommodating the battery cells 20 accommodating space 13.
  • the second part 12 can be a hollow structure with one end open, the first part 11 is a plate-like structure, and the first part 11 is covered with the opening side of the second part 12 to form a box 10 with an accommodating space 13; the first part 11 and The second part 12 can also be a hollow structure with one side open, and the opening side of the first part 11 is covered with the opening side of the second part 12 to form the box 10 with the accommodating space 13 .
  • the first part 11 and the second part 12 may have various shapes, such as a cylinder, a rectangular parallelepiped, and the like.
  • the battery 100 there may be one battery cell 20 or a plurality of battery cells 20 . If there are a plurality of battery cells 20, the plurality of battery cells 20 may be connected in series or in parallel or in a mixed connection.
  • a mixed connection means that the plurality of battery cells 20 are both connected in series and in parallel.
  • the plurality of battery cells 20 can be directly connected in series or in parallel or mixed together, and then the whole formed by the plurality of battery cells 20 is accommodated in the box 10; of course, the plurality of battery cells 20 can also be connected in series first.
  • a battery module is formed in parallel or in a mixed connection, and a plurality of battery modules are connected in series or in parallel or in a mixed connection to form a whole, and are accommodated in the box 10 .
  • FIG. 3 is a schematic structural diagram of a battery module 30 provided in some embodiments of the present application.
  • a plurality of battery cells 20 are first connected in series or in parallel or mixed to form the battery module 30 .
  • a plurality of battery modules 30 are connected in series or in parallel or mixed to form a whole, and are accommodated in the box 10 .
  • the plurality of battery cells 20 in the battery module 30 can be electrically connected through the bus component 31 to realize parallel connection, series connection or mixed connection of the plurality of battery cells 20 in the battery module 30 .
  • the bus component 31 is a metal conductor.
  • FIG. 4 is an exploded view of a battery cell 20 provided by some embodiments of the present application.
  • the battery cell 20 provided in the embodiment of the present application includes a casing 21 and an electrode assembly 22 , and the electrode assembly 22 is accommodated in the casing 21 .
  • the housing 21 may also be used to contain an electrolyte, such as an electrolyte.
  • the housing 21 may include a housing 211 and a cover 212, the housing 211 is a hollow structure with an opening on one side, and the cover 212 covers the opening of the housing 211 and forms a sealing connection to form a A sealed space 213 that accommodates the electrode assembly 22 and the electrolyte.
  • the electrode assembly 22 can be put into the case 211 first, and the electrolyte is filled into the case 211 , and then the cover 212 is closed on the opening of the case 211 .
  • the housing 211 may be in various shapes, such as a cylinder, a rectangular parallelepiped, and the like.
  • the shape of the case 211 may be determined according to the specific shape of the electrode assembly 22 .
  • the cover body 212 may also have various structures, for example, the cover body 212 is a plate-like structure, a hollow structure with one end open, and the like.
  • the casing 211 is a rectangular parallelepiped structure
  • the cover body 212 is a plate-like structure
  • the cover body 212 covers the opening at the top of the casing 211 .
  • the battery cell 20 may further include a positive electrode terminal 23 , a negative electrode terminal 24 and a pressure relief mechanism 25 , and the positive electrode terminal 23 , the negative electrode terminal 24 and the pressure relief mechanism 25 are all mounted on the cover body 212 . Both the positive electrode terminal 23 and the negative electrode terminal 24 are used for electrical connection with the electrode assembly 22 to output electric energy generated by the electrode assembly 22 .
  • the pressure relief mechanism 25 is used for releasing the pressure inside the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value.
  • the pressure relief mechanism 25 may be a component such as a burst valve, a burst disk, a gas valve, a pressure relief valve or a safety valve.
  • the number of electrode assemblies 22 accommodated in the casing 21 may be one or a plurality of them. Illustratively, in Figure 4, there are two electrode assemblies 22.
  • FIG. 5 is a schematic structural diagram of an electrode assembly 22 provided by some embodiments of the present application.
  • the electrode assembly 22 includes a negative electrode piece 221 and a positive electrode piece 222 , and the negative electrode piece 221 and the positive electrode piece 222 are stacked and rolled to form winding structure.
  • the electrode assembly 22 has a flat winding structure.
  • the winding structure has an axial direction Z (not shown in FIG. 5 ), and the axial direction Z of the winding structure is the arrangement direction of the winding axis of the winding structure, which can also be understood as the positive pole piece 222 and the negative pole the width direction of the sheet 221 .
  • the extending direction of the winding member is the arrangement direction of the winding axis of the winding structure .
  • the electrode assembly 22 may further include a separator 223 for separating the positive pole piece 222 and the negative pole piece 221 to reduce the risk of short circuit between the positive pole piece 222 and the negative pole piece 221 .
  • the separator 223 is provided with a large number of through-holes to ensure free passage of electrolyte ions.
  • the material of the isolation film 223 may be PP (polypropylene, polypropylene) or PE (polyethylene, polyethylene) or the like.
  • the negative pole piece 221 , the separator 223 , and the positive pole piece 222 can be stacked together first, and then wound as a whole to form a winding structure.
  • the wound structure has a flat area 224
  • the flat area 224 is the area where the wound structure has a flat structure, that is, the negative pole piece 221 , the positive pole piece 222 and the separator in the flat area 224 223 are substantially straight and parallel to each other. It is understandable that in the flat region 224 , the surface of each layer of negative pole pieces 221 , the surface of each layer of positive pole pieces 222 , and the surface of each layer of separator 223 are all flat.
  • the negative pole pieces 221 in the flat area 224 and the positive pole pieces 222 in the flat area 224 are alternately stacked in the first direction X, that is, in the flat area 224, in the first direction X, a layer of negative pole pieces 221.
  • a layer of positive pole pieces 222 and a layer of negative pole pieces 221 are arranged in sequence.
  • the winding structure may further include a bending area 225, the bending area 225 is connected with the straight area 224, and opposite ends of the straight area 224 may be provided with bending areas 225.
  • the bending area 225 is the area with the bending structure in the winding structure, that is, the negative electrode piece 221, the positive electrode piece 222 and the separator 223 in the bending area 225 are all bent. It can be understood that in the bending region 225, the surface of each layer of negative pole pieces 221, the surface of each layer of positive pole pieces 222, and the surface of each layer of isolation film 223 are curved surfaces. Exemplarily, the curved surfaces are arc surfaces. .
  • FIG. 6 is a partial view of the positive pole piece 222 , the separator 223 and the negative pole piece 221 shown in FIG.
  • the negative electrode active material bodies 2212 on both sides in the thickness direction of the negative electrode current collector 2211 .
  • the positive electrode sheet 222 includes a positive electrode current collector 2221 and a positive electrode active material body 2222 coated on both sides in the thickness direction of the positive electrode current collector 2221 .
  • the negative electrode plate 221 includes a negative electrode active material layer 2213 located in a flat region 224 (see FIG. 5 ), and the positive electrode
  • the sheet 222 includes a positive electrode active material layer 2223 located in the flat region 224 and disposed opposite the negative electrode active material layer 2213 in a first direction X, the first direction X being perpendicular to the axis Z of the winding structure.
  • the first direction X referred to here corresponds to the thickness direction of the negative electrode active material layer 2213 .
  • the negative electrode active material layer 2213 includes a negative electrode main body portion 2213a and negative electrode edge portions 2213b located on both sides of the negative electrode main body portion 2213a in the axial direction Z, and in the first direction X, at least part of the negative electrode main body portion 2213a and the negative electrode edge portion 2213b. At least part of the layer overlaps with the positive electrode active material layer 2223, and the active material capacity per unit area of the negative electrode body portion 2213a is larger than that of the negative electrode edge portion 2213b.
  • the negative electrode main portion 2213a Since the active material capacity per unit area of the negative electrode main portion 2213a is greater than that of the negative electrode edge portion 2213b, the negative electrode main portion 2213a is less prone to lithium precipitation than the negative electrode edge portion 2213b.
  • the capacity of active material per unit area of the negative electrode edge portion 2213b meets the setting requirements, that is, the capacity of the active material per unit area of the negative electrode edge portion 2213b reaches the first preset value, because the capacity of the active material per unit area of the negative electrode main portion 2213a is larger than that of the negative electrode edge portion 2213b
  • the active material capacity per unit area of the negative electrode body portion 2213a is greater than the first preset value, which is equivalent to increasing the active material capacity per unit area of the negative electrode body portion 2213a and increasing the CB of the negative electrode body portion 2213a.
  • the negative electrode active material layer 2213 is the portion of the negative electrode active material body 2212 of the negative electrode pole piece 221 in the flat region 224 .
  • the structure of the portion of the negative electrode active material body 2212 in the flat region 224 and the structure of the portion of the negative electrode active material body 2212 in the bent region 225 may be the same or different.
  • the positive electrode active material layer 2223 is the portion of the positive electrode active material body 2222 of the positive electrode sheet 222 in the flat region 224 .
  • the structure of the portion of the positive electrode active material body 2222 in the flat region 224 and the structure of the portion of the positive electrode active material body 2222 in the bent region 225 may be the same or different.
  • the CB (Cell Balance) value of the negative electrode main body 2213a is Q1/Q2
  • Q1 is the active material capacity per unit area of the negative electrode main body 2213a
  • Q2 is the difference between the positive electrode active material layer 2223 and the negative electrode main body 2213a.
  • the negative electrode main body portion 2213a and the negative electrode edge portion 2213b are continuously distributed in the axial direction Z, that is, the negative electrode active material layer 2213 of the negative electrode pole piece 221 is uninterrupted in the axial direction Z, which is beneficial to improve the battery cell 20. capacity.
  • the negative electrode main body portion 2213a and the negative electrode edge portion 2213b may also be spaced apart in the axial direction Z.
  • the active material capacity per unit area of the negative electrode main body portion 2213a may be greater than the active material capacity per unit area of the negative electrode edge portion 2213b in various ways.
  • the gram capacity of the active material of the negative electrode body portion 2213a is greater than the gram capacity of the active material of the negative electrode edge portion 2213b. That is to say, by increasing the gram capacity of the active material of the negative electrode body portion 2213a, the active material capacity per unit area of the negative electrode body portion 2213a can be increased, so that the active material capacity per unit area of the negative electrode body portion 2213a is greater than that of the negative electrode edge portion 2213b The active material capacity per unit area.
  • the gram capacity refers to the ratio of the capacitance released by the active material to the mass of the active material.
  • the thickness of the negative electrode body portion 2213a and the thickness of the negative electrode edge portion 2213b may be equal.
  • the active material of the negative electrode main part 2213a and the active material of the negative electrode edge part 2213b may be different, for example, the active material of the negative electrode main part 2213a is silicon, and the active material of the negative electrode edge part 2213b is graphite.
  • the active material capacity per unit area of the negative electrode main body portion 2213a may be greater than the active material capacity per unit area of the negative electrode edge portion 2213b by other means.
  • the ratio of the weight of the active material of the negative body portion 2213a to the weight of the negative body portion 2213a is greater than the ratio of the weight of the active material of the negative edge portion 2213b to the weight of the negative edge portion 2213b. That is to say, by increasing the specific gravity of the active material of the negative electrode body portion 2213a, the active material capacity per unit area of the negative electrode body portion 2213a can be increased, so that the active material capacity per unit area of the negative electrode body portion 2213a is greater than that of the negative electrode edge portion 2213b. Active material capacity per unit area.
  • the components of the negative electrode body portion 2213a and the negative electrode edge portion 2213b may both include active materials, conductive agents and binders, and the active materials of the negative electrode body portion 2213a and the negative electrode edge portion 2213b may be the same.
  • the positive electrode active material layer 2223 may have various structures.
  • the positive electrode active material layer 2223 includes a positive electrode body portion 2223a and positive electrode edge portions 2223b located on both sides of the positive electrode body portion 2223a in the axial direction Z.
  • the first direction X at least part of the positive electrode body portion 2223a and At least part of the positive electrode edge portion 2223b overlaps with the negative electrode active material layer 2213, and the active material capacity per unit area of the positive electrode body portion 2223a is equal to the active material capacity per unit area of the positive electrode edge portion 2223b.
  • FIG. 8 is a partial cross-sectional view of the electrode assembly 22 provided by some embodiments of the present application.
  • the positive electrode active material layer 2223 includes a positive electrode main body portion 2223 a and a positive electrode main body portion 2223 a in the axial direction Z.
  • the active material capacity per unit area of the positive electrode main body portion 2223a is smaller than the active material capacity per unit area of the positive electrode edge portion 2223b, so that the portion where the negative electrode active material layer 2213 and the positive electrode main body portion 2223a overlap is compared with the negative electrode active material layer 2213 and the negative electrode edge portion 2213b.
  • the part is less prone to lithium precipitation.
  • the active material capacity per unit area of the positive electrode edge portion 2223b meets the setting requirements, that is, the active material capacity per unit area of the positive electrode edge portion 2223b reaches the second preset value, since the active material capacity per unit area of the positive electrode main portion 2223a is smaller than that of the positive electrode edge portion 2223b
  • the active material capacity per unit area of the positive electrode main body portion 2223a is smaller than the second preset value, which is equivalent to reducing the active material capacity per unit area of the positive electrode main body portion 2223a, increasing the amount of the negative electrode active material layer 2213 and the negative electrode active material layer 2213.
  • the CB value of the portion where the positive electrode main body portion 2223a overlaps improves the expansion resistance threshold of the region where the positive electrode main body portion 2223a is located in the positive electrode pole piece 222, so that the portion where the negative electrode active material layer 2213 overlaps with the positive electrode main body portion 2223a is less prone to lithium precipitation, thereby The risk of lithium deposition in the middle region of the negative electrode active material layer 2213 in the first direction X is reduced.
  • the positive electrode main body portion 2223a and the positive electrode edge portion 2223b are continuously distributed in the axial direction Z, that is, the positive active material layer 2223 of the positive electrode sheet 222 is uninterrupted in the axial direction Z, which is beneficial to improve the battery cell 20. capacity.
  • the positive electrode main body portion 2223a and the positive electrode edge portion 2223b may also be spaced apart in the axial direction Z.
  • At least a portion of the negative electrode body portion 2213a overlaps with at least a portion of the positive electrode body portion 2223a, and at least a portion of the negative electrode edge portion 2213b overlaps at least a portion of the positive electrode edge portion 2223b.
  • the active material capacity per unit area of the negative electrode main portion 2213a is greater than the active material capacity per unit area of the negative electrode edge portion 2213b
  • the active material capacity per unit area of the positive electrode main portion 2223a is smaller than the active material capacity per unit area of the positive electrode edge portion 2223b, in the first direction X
  • at least part of the negative electrode main body part 2213a overlaps with at least part of the positive electrode main body part 2223a, and the negative electrode main body part 2213a is less prone to lithium precipitation, which further reduces the risk of lithium precipitation in the middle region of the negative electrode active material layer 2213 in the first direction X. .
  • the projection of the negative electrode main body part 2213a in the first direction X is the same as the positive electrode main body part 2223a in the first direction X.
  • the projection in the direction X at least partially overlaps; in the first direction X, at least part of the negative edge portion 2213b overlaps with at least a portion of the positive edge portion 2223b, that is, the projection of the negative edge portion 2213b on the first direction X and the positive edge At least a part of the projection of the portion 2223b in the first direction X overlaps.
  • the negative electrode body portion 2213a and the positive electrode body portion 2223a may completely overlap. In order to further reduce the risk of lithium precipitation in the main body portion 2213a of the negative electrode.
  • the negative electrode edge portion 2213b and the positive electrode edge portion 2223b may completely overlap.
  • the active material capacity per unit area of the positive electrode main body portion 2223a may be smaller than the active material capacity per unit area of the positive electrode edge portion 2223b in various ways.
  • the gram capacity of the active material of the positive electrode body portion 2223a is smaller than the gram capacity of the active material of the positive electrode edge portion 2223b. That is, by reducing the gram capacity of the active material of the positive electrode body portion 2223a, the active material capacity per unit area of the positive electrode body portion 2223a can be reduced, so that the active material capacity per unit area of the positive electrode body portion 2223a is smaller than that of the positive electrode edge portion 2223b The active material capacity per unit area.
  • the thickness of the positive electrode body portion 2223a and the thickness of the positive electrode edge portion 2223b may be equal, and the active material of the positive electrode body portion 2223a and the active material of the positive electrode edge portion 2223b may be different.
  • the active material of the positive electrode body portion 2223a is Lithium iron phosphate
  • the active material of the edge portion 2223b of the positive electrode is ternary lithium.
  • FIG. 9 is a partial cross-sectional view of the electrode assembly 22 provided by further embodiments of the present application.
  • the positive electrode main body portion 2223 a includes a first positive electrode coating layer 2223 c and a Two positive coating 2223d.
  • the gram capacity of the active material of the first positive electrode coating 2223c is less than or equal to the gram capacity of the active material of the positive edge portion 2223b, and the gram capacity of the active material of the second positive electrode coating 2223d is smaller than the gram capacity of the active material of the first positive electrode coating 2223c Therefore, the gram capacity of the active material of the positive electrode body portion 2223a is smaller than the gram capacity of the active material of the positive electrode edge portion 2223b, so that the active material capacity per unit area of the positive electrode body portion 2223a is smaller than the active material capacity per unit area of the positive electrode edge portion 2223b.
  • the first positive electrode coating 2223c may be an active material layer containing an active material, or an inactive material layer containing no active material.
  • the first positive electrode coating 2223c is a metal conductive layer, which only plays a conductive role .
  • the total thickness of the first positive electrode coating layer 2223c and the second positive electrode coating layer 2223d may be equal to the thickness of the positive electrode edge portion 2223b.
  • the gram capacity of the active material of the first positive electrode coating 2223c may be equal to the gram capacity of the active material of the positive edge portion 2223b, the active material of the first positive electrode coating 2223c and the active material of the positive electrode edge portion 2223b may be the same, the first positive electrode coating
  • the active material of 2223c may be different from the active material of the second cathode coating 2223d.
  • first positive electrode coating layer 2223c and the second positive electrode coating layer 2223d are stacked in the first direction X, and the first positive electrode coating layer 2223c may be coated on the positive electrode current collector 2221, and the second positive electrode coating layer 2223d may be coated on the positive electrode current collector 2221. Coated on the side of the first positive electrode coating 2223c away from the positive electrode current collector 2221, or the second positive electrode coating 2223d is coated on the positive electrode current collector 2221, and the first positive electrode coating 2223c is coated on the second positive electrode coating 2223d away from One side of the positive electrode current collector 2221 .
  • the active material capacity per unit area of the positive electrode main body portion 2223a may be smaller than the active material capacity per unit area of the positive electrode edge portion 2223b by other means.
  • the ratio of the weight of the active material of the positive body portion 2223a to the weight of the positive body portion 2223a is less than the ratio of the weight of the active material of the positive edge portion 2223b to the weight of the positive edge portion 2223b. That is, by reducing the specific gravity of the active material of the positive electrode main body portion 2223a, the active material capacity per unit area of the positive electrode main body portion 2223a can be reduced, so that the active material capacity per unit area of the positive electrode main body portion 2223a is smaller than that of the positive electrode edge portion 2223b. Active material capacity per unit area.
  • the components of the positive electrode body portion 2223a and the positive electrode edge portion 2223b may both include active materials, conductive agents and binders, and the active materials of the positive electrode body portion 2223a and the positive electrode edge portion 2223b may be the same.
  • FIG. 10 is a partial cross-sectional view of the electrode assembly 22 according to further embodiments of the present application.
  • the thickness of the positive electrode body portion 2223a is smaller than that of the positive electrode edge portion 2223b.
  • the active material capacity per unit area of the positive electrode body portion 2223a can also be achieved to be smaller than that of the positive electrode edge portion 2223b.
  • the thickness of the positive electrode pole piece 222 is relatively thin in the region where the positive electrode main body portion 2223a is located, which increases the resistance threshold of the expansion force in this region to reduce the phenomenon of lithium precipitation happened.
  • the material of the positive electrode body portion 2223a is the same as that of the positive electrode edge portion 2223b. It can be understood that the composition of the positive electrode body portion 2223a is the same as that of the positive electrode edge portion 2223b, and the proportion of each component in the positive electrode body portion 2223a is the same as that in the positive electrode edge portion 2223b.
  • the composition of the positive electrode body portion 2223a and the composition of the positive electrode edge portion 2223b include active material, a conductive agent and a binder.
  • the conductive agent and the binder are the same, the proportion of the active material in the positive electrode body portion 2223a is the same as that in the positive electrode edge portion 2223b, and the proportion of the conductive agent in the positive electrode body portion 2223a is the same as that in the positive electrode edge portion 2223b.
  • the proportion of the conductive agent in the positive electrode main body portion 2223a is the same as that of the adhesive agent in the positive electrode edge portion 2223b.
  • the negative electrode active material layer 2213 in the case where the active material capacity per unit area of the positive electrode main body portion 2223a in the positive electrode active material layer 2223 is smaller than the active material capacity per unit area of the positive electrode edge portion 2223b, the negative electrode active material layer 2213
  • the capacity of active material per unit surface of the negative electrode main body portion 2213a may also be equal to the capacity of active material per unit surface of the negative electrode edge portion 2213b.
  • FIG. 11 is a flowchart of a method for manufacturing the electrode assembly 22 provided by some embodiments of the present application.
  • the method for manufacturing the electrode assembly 22 includes:
  • the winding structure has a flat area 224
  • the negative electrode sheet 221 includes a negative electrode active material layer 2213 located in the flat area 224
  • the positive electrode electrode 222 includes a negative electrode active material layer 2213 located in the flat area 224 and in the first direction X with the negative electrode active material layer 2213.
  • the first direction X is perpendicular to the axial direction Z of the winding structure.
  • the negative electrode active material layer 2213 includes a negative electrode main body portion 2213a and negative electrode edge portions 2213b located on both sides of the negative electrode main body portion 2213a in the axial direction Z, and in the first direction X, at least part of the negative electrode main body portion 2213a and the negative electrode edge portion 2213b.
  • the positive electrode active material layer 2223 includes the positive electrode main body portion 2223a and the axial In the first direction X, at least part of the positive electrode body part 2223a and at least part of the positive electrode edge part 2223b overlap with the negative electrode active material layer 2213, and the positive electrode body
  • the active material capacity per unit area of the portion 2223a is smaller than the active material capacity per unit area of the positive electrode edge portion 2223b.
  • FIG. 12 is a flow chart of a method for manufacturing an electrode assembly 22 provided in some other embodiments of the present application, and further provides a separator for separating the positive pole piece 222 and the negative pole piece 221 223 , stacking and winding the negative pole piece 221 , the separator 223 and the positive pole piece 222 to form a winding structure.
  • FIG. 13 is a schematic block diagram of a manufacturing apparatus 2000 of an electrode assembly 22 provided by some embodiments of the present application.
  • the manufacturing apparatus 2000 includes a providing device 2100 and an assembling device 2200 .
  • the providing device 2100 is used to provide the positive electrode piece 222 and
  • the negative pole piece 221 and the assembling device 2200 are used for stacking and winding the negative pole piece 221 and the positive pole piece 222 to form a winding structure.
  • the winding structure has a flat area 224
  • the negative electrode sheet 221 includes a negative electrode active material layer 2213 located in the flat area 224
  • the positive electrode electrode 222 includes a negative electrode active material layer 2213 located in the flat area 224 and in the first direction X with the negative electrode active material layer 2213.
  • the first direction X is perpendicular to the axial direction Z of the winding structure;
  • the negative electrode active material layer 2213 includes a negative electrode main body portion 2213a and negative electrode edge portions 2213b located on both sides of the negative electrode main body portion 2213a in the axial direction Z, and in the first direction X, at least part of the negative electrode main body portion 2213a and the negative electrode edge portion 2213b.
  • the positive electrode active material layer 2223 includes the positive electrode main body portion 2223a and the axial In the first direction X, at least part of the positive electrode body part 2223a and at least part of the positive electrode edge part 2223b overlap with the negative electrode active material layer 2213, and the positive electrode body
  • the active material capacity per unit area of the portion 2223a is smaller than the active material capacity per unit area of the positive electrode edge portion 2223b.
  • the providing device 2100 is further configured to provide a separator 223 for separating the positive electrode sheet 222 and the negative electrode electrode sheet 221, and to laminate and wind the negative electrode electrode sheet 221, the separator film 223 and the positive electrode electrode sheet 222 to form a roll around the structure.
  • the embodiment of the present application also provides a method for testing the CB value of the electrode assembly 22, and the steps for testing the CB value are as follows:
  • Step 1) Average discharge capacity test of the single-sided active material layer of the positive electrode. Take the positive electrode pieces of the above examples, and use a punching die to obtain a small round piece containing a positive electrode single-sided active material layer.
  • the lithium metal sheet is used as the counter electrode
  • the Celgard film is used as the separator
  • the EC+DMC+DEC of LiPF6 (1mol/L) is dissolved (ethylene carbonate, dimethyl carbonate, and diethyl carbonate with a volume ratio of 1:1:1).
  • the solution of ester was the electrolyte, and 6 identical CR2430 button cells were assembled in an argon-protected glove box.
  • the average value of the discharge capacity of the six coin cells is the average discharge capacity of the single-sided active material layer of the positive electrode.
  • the positive electrode active material is lithium iron phosphate (LFP)
  • the upper limit cut-off voltage x1V 3.75V
  • the lower limit cut-off voltage y1V 2V.
  • the positive electrode active material is lithium nickel cobalt manganese oxide (NCM)
  • the upper limit cut-off voltage x1V 4.25V
  • the lower limit cut-off voltage y1V 2.8V.
  • Step 2) Average charge capacity test of the single-sided active material layer of the negative electrode. Take the negative pole pieces of each of the above embodiments, and use a punching die to obtain a small round piece with the same area as the positive small round piece in the above step 1) and including a negative electrode single film layer.
  • the lithium metal sheet is used as the counter electrode
  • the Celgard film is used as the separator
  • the EC+DMC+DEC of LiPF6 (1mol/L) is dissolved (ethylene carbonate, dimethyl carbonate, and diethyl carbonate with a volume ratio of 1:1:1).
  • the solution of ester was the electrolyte, and six CR2430 button cells were assembled in an argon-protected glove box.
  • the average value of the charging capacity of the 6 button batteries is the average charging capacity of the negative electrode single film layer.
  • the negative electrode active material is graphite
  • the upper limit cut-off voltage x2V 2V
  • the lower limit cut-off voltage y2V 5mV.
  • the negative electrode active material is silicon
  • the upper limit cut-off voltage x2V 2V
  • the lower limit cut-off voltage y2V 5mV.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)

Abstract

本申请实施例提供了一种电极组件、电池单体、电池及电极组件的制造方法和设备，属于电池技术领域。电极组件包括负极极片和正极极片，负极极片包括位于电极组件的平直区的负极活性物质层，正极极片包括位于平直区的正极活性物质层，第一方向垂直于卷绕结构的轴向。负极活性物质层包括负极主体部和在轴向上位于负极主体部的两侧的负极边缘部，负极主体部的单位面积活性物质容量大于负极边缘部的单位面积活性物质容量；和/或，正极活性物质层包括正极主体部和在轴向上位于正极主体部的两侧的正极边缘部，正极主体部的单位面积活性物质容量小于正极边缘部的单位面积活性物质容量。这种结构的电极组件能够有效降低析锂风险，提高电池的安全性。

Description

电极组件、电池单体、电池及电极组件的制造方法和设备 技术领域
本申请涉及电池技术领域，具体而言，涉及一种电极组件、电池单体、电池及电极组件的制造方法和设备。
背景技术
可再充电电池，可以称为二次电池，是指在电池放电后可通过充电的方式使活性物质激活而继续使用的电池。可再充电电池广泛用于电子设备，例如手机、笔记本电脑、电瓶车、电动汽车、电动飞机、电动轮船、电动玩具汽车、电动玩具轮船、电动玩具飞机和电动工具等等。
在电池技术的发展中，除了需要考虑电池性能的问题以外，还需要考虑电池的安全性。因此，如何提高电池的安全性是电池技术中一个亟待解决的问题。
发明内容
本申请实施例提供一种电极组件、电池单体、电池及电极组件的制造方法和设备，能够有效降低析锂。
第一方面，本申请实施例提供一种电极组件，包括负极极片和正极极片，所述负极极片和所述正极极片层叠并卷绕形成具有平直区的卷绕结构，所述负极极片包括位于所述平直区的负极活性物质层，所述正极极片包括位于所述平直区且与所述负极活性物质层在第一方向相对设置的正极活性物质层，所述第一方向垂直于所述卷绕结构的轴向；所述负极活性物 质层包括负极主体部和在所述轴向上位于负极主体部的两侧的负极边缘部，在所述第一方向上，所述负极主体部的至少部分和所述负极边缘部的至少部分均与所述正极活性物质层重叠，所述负极主体部的单位面积活性物质容量大于所述负极边缘部的单位面积活性物质容量；和/或，所述正极活性物质层包括正极主体部和在所述轴向上位于正极主体部的两侧的正极边缘部，在所述第一方向上，所述正极主体部的至少部分和所述正极边缘部的至少部分均与所述负极活性物质层重叠，所述正极主体部的单位面积活性物质容量小于所述正极边缘部的单位面积活性物质容量。
上述方案中，负极主体部的单位面积活性物质容量大于负极边缘部的单位面积活性物质容量，使得负极主体部相较于负极边缘部更不易出现析锂。在负极边缘部的单位面积活性物质容量满足设置要求时，即负极边缘部的单位面积活性物质容量达到第一预设值，由于负极主体部的单位面积活性物质容量大于负极边缘部的单位面积活性物质容量，即负极主体部的单位面积活性物质容量大于第一预设值，相当于增大了负极主体部的单位面积活性物质容量，增大了负极主体部的CB值，使得负极主体部不易出现析锂，从而降低了负极活性物质层在第一方向上的中间区域出现析锂现象的风险。
正极主体部的单位面积活性物质容量小于正极边缘部的单位面积活性物质容量，使得负极活性物质层与正极主体部重叠的部分相较于负极活性物质层与负极边缘部重叠的部分更不易出现析锂。在正极边缘部的单位面积活性物质容量满足设置要求时，即正极边缘部的单位面积活性物质容量达到第二预设值，由于正极主体部的单位面积活性物质容量小于正极边缘部的单位面积活性物质容量，即正极主体部的单位面积活性物质容量小于第二预设值，相当于减小了正极主体部的单位面积活性物质容量，增大了负极活性物质层与正极主体部重叠的部分的CB值，使得负极活性物质 层与正极主体部重叠的部分不易出现析锂，从而降低了负极活性物质层在第一方向上的中间区域出现析锂现象的风险。
在一些实施例中，所述负极活性物质层包括所述负极主体部和所述负极边缘部，所述正极活性物质层包括所述正极主体部和所述正极边缘部；在所述第一方向上，所述负极主体部的至少部分与所述正极主体部的至少部分重叠，所述负极边缘部的至少部分与所述正极边缘部的至少部分重叠。
上述方案中，由于负极主体部的单位面积活性物质容量大于负极边缘部的单位面积活性物质容量，正极主体部的单位面积活性物质容量小于正极边缘部的单位面积活性物质容量，在第一方向上，负极主体部的至少部分与正极主体部的至少部分重叠，负极主体部更不易出现析锂，进一步降低了负极活性物质层在第一方向上的中间区域出现析锂风险。
在一些实施例中，在所述第一方向上，所述负极主体部与所述正极主体部完全重叠。
上述方案中，在第一方向上，负极主体部与正极主体部完全重叠，可进一步降低负极主体部出现析锂风险。
在一些实施例中，所述负极主体部的活性材料的克容量大于所述负极边缘部的活性材料的克容量。
上述方案中，负极主体部的活性材料的克容量大于负极边缘部的活性材料的克容量，也就是说，通过增大负极主体部的活性材料的克容量，可增大负极主体部的单位面积活性物质容量，以实现负极主体部的单位面积活性物质容量大于负极边缘部的单位面积活性物质容量。
在一些实施例中，所述负极主体部的活性材料的重量与所述负极主体部的重量的比值大于所述负极边缘部的活性材料的重量与所述负极边缘 部的重量的比值。
上述方案中，负极主体部的活性材料的重量与负极主体部的重量的比值大于负极边缘部的活性材料的重量与负极边缘部的重量的比值，也就是说，通过增大负极主体部的活性材料的比重，可增大负极主体部的单位面积活性物质容量，以实现负极主体部的单位面积活性物质容量大于负极边缘部的单位面积活性物质容量。
在一些实施例中，所述正极主体部的活性材料的克容量小于所述正极边缘部的活性材料的克容量。
上述方案中，正极主体部的活性材料的克容量小于正极边缘部的活性材料的克容量，也就是说，通过减小正极主体部的活性材料的克容量，可减小正极主体部的单位面积活性物质容量，以实现正极主体部的单位面积活性物质容量小于正极边缘部的单位面积活性物质容量。
在一些实施例中，所述正极主体部包括在所述第一方向层叠设置的第一正极涂层和第二正极涂层；所述第一正极涂层的活性材料的克容量小于或等于正极边缘部的活性材料的克容量，所述第二正极涂层的活性材料的克容量小于所述第一正极涂层的活性材料的克容量。
上述方案中，正极主体部包括在第一方向层叠设置的第一正极涂层和第二正极涂层，由于第一正极涂层的活性材料的克容量小于或等于正极边缘部的活性材料的克容量，第二正极涂层的活性材料的克容量小于第一正极涂层的活性材料的克容量，使得正极主体部的活性材料的克容量小于正极边缘部的活性材料的克容量，进而使正极主体部的单位面积活性物质容量小于正极边缘部的单位面积活性物质容量。
在一些实施例中，所述正极主体部的活性材料的重量与所述正极主体部的重量的比值小于所述正极边缘部的活性材料的重量与正极边缘部的 重量的比值。
上述方案中，正极主体部的活性材料的重量与正极主体部的重量的比值小于正极边缘部的活性材料的重量与正极边缘部的重量的比值，也就是说，通过减小正极主体部的活性材料的比重，可减小正极主体部的单位面积活性物质容量，以实现正极主体部的单位面积活性物质容量小于正极边缘部的单位面积活性物质容量。
在一些实施例中，所述正极主体部的厚度小于所述正极边缘部的厚度。
上述技术方案中，通过减小正极主体部的厚度，使得正极主体部的厚度小于正极边缘部的厚度，也可以实现正极主体部的单位面积活性物质容量小于正极边缘部的单位面积活性物质容量。此外，由于正极主体部的厚度小于正极边缘部的厚度，使得正极极片在正极主体部所在的区域厚度相对较薄，提高了该区域的耐膨胀力阈值，以降低析锂现象的发生。
在一些实施例中，所述负极主体部与所述负极边缘部在所述轴向上连续分布。
上述方案中，负极主体部与负极边缘在轴向上连续分布，即负极极片的负极活性物质层在轴向上不间断，有利于提高电池单体的容量。
在一些实施例中，所述正极主体部与所述正极边缘部在所述轴向上连续分布。
上述方案中，正极主体部与正极边缘在轴向上连续分布，即正极极片的正极活性物质层在轴向上不间断，有利于提高电池单体的容量。
第二方面，本申请实施例提供一种电池单体，包括外壳和上述第一方面任意一个实施例提供的电极组件；所述电极组件容纳于所述外壳内。
第三方面，本申请实施例提供一种电池，包括箱体和上述第二方面任意一个实施例提供的电池单体，所述电池单体容纳于所述箱体内。
第四方面，本申请实施例提供一种用电设备，包括上述第三方面任意一个实施例提供的电池。
第五方面，本申请实施例提供一种电极组件的制造方法，包括：提供负极极片和正极极片；将所述负极极片和所述正极极片层叠并卷绕形成卷绕结构；其中，所述卷绕结构具有平直区，所述负极极片包括位于所述平直区的负极活性物质层，所述正极极片包括位于所述平直区且与所述负极活性物质层在第一方向相对设置的正极活性物质层，所述第一方向垂直于所述卷绕结构的轴向；所述负极活性物质层包括负极主体部和在所述轴向上位于负极主体部的两侧的负极边缘部，在所述第一方向上，所述负极主体部的至少部分和所述负极边缘部的至少部分均与所述正极活性物质层重叠，所述负极主体部的单位面积活性物质容量大于所述负极边缘部的单位面积活性物质容量；和/或，所述正极活性物质层包括正极主体部和在所述轴向上位于正极主体部的两侧的正极边缘部，在所述第一方向上，所述正极主体部的至少部分和所述正极边缘部的至少部分均与所述负极活性物质层重叠，所述正极主体部的单位面积活性物质容量小于所述正极边缘部的单位面积活性物质容量。
第六方面，本申请实施例还提供一种电极组件的制造设备，包括；提供装置，用于提供正极极片和负极极片；组装装置，用于将所述负极极片和所述正极极片层叠并卷绕形成卷绕结构；其中，所述卷绕结构具有平直区，所述负极极片包括位于所述平直区的负极活性物质层，所述正极极片包括位于所述平直区且与所述负极活性物质层在第一方向相对设置的正极活性物质层，所述第一方向垂直于所述卷绕结构的轴向；所述负极活性 物质层包括负极主体部和在所述轴向上位于负极主体部的两侧的负极边缘部，在所述第一方向上，所述负极主体部的至少部分和所述负极边缘部的至少部分均与所述正极活性物质层重叠，所述负极主体部的单位面积活性物质容量大于所述负极边缘部的单位面积活性物质容量；和/或，所述正极活性物质层包括正极主体部和在所述轴向上位于正极主体部的两侧的正极边缘部，在所述第一方向上，所述正极主体部的至少部分和所述正极边缘部的至少部分均与所述负极活性物质层重叠，所述正极主体部的单位面积活性物质容量小于所述正极边缘部的单位面积活性物质容量。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对本申请实施例中所需要使用的附图作简单地介绍，显而易见地，下面所描述的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
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爆炸图；
图3为本申请一些实施例提供的电池模块的结构示意图；
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电极组件的结构示意图；
图6为图5所示的正极极片、隔离膜和负极极片展开后的局部视图；
图7为图5所示的电极组件的A-A剖视图；
图8为本申请一些实施例提供的电极组件的局部剖视图；
图9为本申请又一些实施例提供的电极组件的局部剖视图；
图10为本申请再一些实施例提供的电极组件的局部剖视图；
图11为本申请一些实施例提供的电极组件的制造方法的流程图；
图12为本申请又一些实施例提供的电极组件的制造方法的流程图；
图13为本申请一些实施例提供的电极组件的制造设备的示意性框图；
在附图中，附图并未按照实际的比例绘制。
标记说明：10-箱体；11-第一部分；12-第二部分；13-容纳空间；20-电池单体；21-外壳；211-壳体；212-盖体；213-密封空间；22-电极组件；221-负极极片；2211-负极集流体；2212-负极活性物质体；2213-负极活性物质层；2213a-负极主体部；2213b-负极边缘部；222-正极极片；2221-正极集流体；2222-正极活性物质体；2223-正极活性物质层；2223a-正极主体部；2223b-正极边缘部；2223c-第一正极涂层；2223d-第二正极涂层；223-隔离膜；224-平直区；225-弯折区；23-正极电极端子；24-负极电极端子；25-泄压机构；30-电池模块；31-汇流部件；100-电池；200-控制器；300-马达；1000-车辆；2000-制造设备；2100-提供装置；2200-组装装置；Z-轴向；X-第一方向。
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地描述，显然，所描述的实施例是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
除非另有定义，本申请所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同；本申请中在申请的说明书中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本申 请；本申请的说明书和权利要求书及上述附图说明中的术语“包括”和“具有”以及它们的任何变形，意图在于覆盖不排他的包含。本申请的说明书和权利要求书或上述附图中的术语“第一”、“第二”等是用于区别不同对象，而不是用于描述特定顺序或主次关系。
在本申请中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。
在本申请的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”、“附接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。
本申请中术语“和/或”，仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本申请中字符“/”，一般表示前后关联对象是一种“或”的关系。
在本申请的实施例中，相同的附图标记表示相同的部件，并且为了简洁，在不同实施例中，省略对相同部件的详细说明。应理解，附图示出的本申请实施例中的各种部件的厚度、长宽等尺寸，以及集成装置的整体厚度、长宽等尺寸仅为示例性说明，而不应对本申请构成任何限定。
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体，正极活性物质体涂覆于正极集流体的表面，未涂敷正极活性物质体的正极集流体凸出于已涂覆正极活性物质体的正极集流体，未涂敷正极活性物质体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体，负极活性物质体涂覆于负极集流体的表面，未涂敷负极活性物质体的负极集流体凸出于已涂覆负极活性物质体的负极集流体，未涂敷负极活性物质体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。此外，电极组件可以是卷绕式结构，也可以是叠片式结构，本申请实施例并不限于此。
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。
对于锂离子电池而言，在充电时，锂离子从正极脱离并嵌入负极；在放电时，锂离子从负极脱离并嵌入正极。锂离子电池在充电时，可能会发生一些异常情况而导致析锂，比如，负极嵌锂空间不足、锂离子迁移阻力过大、锂离子过快从正极脱离出但无法等量嵌入负极等异常引起的无法嵌入负极的锂离子只能在负极表面得到电子，从而形成锂单质的现象，即为析锂现象。
发明人发现，在电池单体中，电极组件在平直区的极片的中间区域膨胀力较大，电解液浸润困难，从而导致该区域负极极片容易出现析锂现 象。
鉴于此，本申请实施例提供一种电极组件，包括负极极片和正极极片，负极极片和正极极片层叠并卷绕形成具有平直区的卷绕结构，负极极片包括位于平直区的负极活性物质层，正极极片包括位于平直区且与负极活性物质层在第一方向相对设置的正极活性物质层，第一方向垂直于卷绕结构的轴向。负极活性物质层包括负极主体部和在轴向上位于负极主体部的两侧的负极边缘部，在第一方向上，负极主体部的至少部分和负极边缘部的至少部分均与正极活性物质层重叠，负极主体部的单位面积活性物质容量大于负极边缘部的单位面积活性物质容量；和/或，正极活性物质层包括正极主体部和在轴向上位于正极主体部的两侧的正极边缘部，在第一方向上，正极主体部的至少部分和正极边缘部的至少部分均与负极活性物质层重叠，正极主体部的单位面积活性物质容量小于正极边缘部的单位面积活性物质容量。这种结构的电极组件能够有效降低析锂风险，提高电池的安全性。
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的爆炸图，电池100包括箱体10和电池单体20(图2未示出)，电池单体20容纳于箱体10内。
箱体10用于容纳电池单体20，箱体10可以是多种结构。在一些实施例中，箱体10可以包括第一部分11和第二部分12，第一部分11与第二部分12相互盖合，第一部分11和第二部分12共同限定出用于容纳电池单体20的容纳空间13。可以是第二部分12为一端开口的空心结构，第一部分11为板状结构，第一部分11盖合于第二部分12的开口侧，以形成具有容纳空间13的箱体10；第一部分11和第二部分12也可以是均为一侧开口的空心结构，第一部分11的开口侧盖合于第二部分12的开口侧，以形成具有容纳空间13的箱体10。当然，第一部分11和第二部分12可以是多种形状，比如，圆柱体、长方体等。
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。
在一些实施例中，请参照图3，图3为本申请一些实施例提供的电池模块30的结构示意图，多个电池单体20先串联或并联或混联组成电池模块30。多个电池模块30再串联或并联或混联形成一个整体，并容纳于箱体10内。
电池模块30中的多个电池单体20之间可通过汇流部件31实现电连接，以实现电池模块30中的多个电池单体20的并联或串联或混联。示例性的，汇流部件31为金属导体。
请参照图4，图4为本申请一些实施例提供的电池单体20的爆炸图。本申请实施例提供的电池单体20包括外壳21和电极组件22，电极组件22容纳于外壳21内。
在一些实施例中，外壳21还可用于容纳电解质，例如电解液。
在一些实施例中，外壳21可以包括壳体211和盖体212，壳体211为一侧开口的空心结构，盖体212盖合于壳体211的开口处并形成密封连接，以形成用于容纳电极组件22和电解质的密封空间213。
在组装电池单体20时，可先将电极组件22放入壳体211内，并向壳体211内填充电解质，再将盖体212盖合于壳体211的开口。
壳体211可以是多种形状，比如，圆柱体、长方体等。壳体211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，则可选用为圆柱体壳体；若电极组件22为长方体扁平结构，则可选用长方体壳体。当然，盖体212也可以是多种结构，比如，盖体212为板状结构、一端开口的空心结构等。示例性的，在图4中，壳体211为长方体结构，盖体212为板状结构，盖体212盖合于壳体211顶部的开口处。
在一些实施例中，电池单体20还可以包括正极电极端子23、负极电极端子24和泄压机构25，正极电极端子23、负极电极端子24和泄压机构25均安装于盖体212上。正极电极端子23和负极电极端子24均用于与电极组件22电连接，以输出电极组件22所产生的电能。泄压机构25用于在电池单体20的内部压力或温度达到预定值时泄放电池单体20内部的压力。
示例性的，泄压机构25可以是诸如防爆阀、防爆片、气阀、泄压阀或安全阀等部件。
需要说明的是，在电池单体20中，容纳于外壳21内的电极组件22可以是一个，也可以是多个。示例性的，在图4中，电极组件22为两 个。
接下来结合附图对电极组件22的具体结构进行详细阐述。
请参照图5，图5为本申请一些实施例提供的电极组件22的结构示意图，电极组件22包括负极极片221和正极极片222，负极极片221和正极极片222层叠并卷绕形成卷绕结构。
示例性的，电极组件22呈扁平状卷绕结构。
需要说明的是，卷绕结构具有轴向Z(图5未视图)，卷绕结构的轴向Z即为卷绕结构的卷绕轴线的布置方向，也可以理解为正极极片222和负极极片221的宽度方向。在通过卷绕件(位于卷绕结构的卷芯位置)对负极极片221和正极极片222层叠后进行卷绕时，卷绕件的延伸方向即为卷绕结构的卷绕轴线的布置方向。
在一些实施例中，电极组件22还可以包括隔离膜223，隔离膜223用于隔离正极极片222和负极极片221，以降低正极极片222与负极极片221之间出现短路的风险。
其中，隔离膜223设有大量贯通的微孔，以保证电解质离子自由通过。示例性的，隔离膜223的材质可以为PP(polypropylene，聚丙烯)或PE(polyethylene，聚乙烯)等。
在实际制造过程中，可先将负极极片221、隔离膜223、正极极片222层叠在一起，再整体卷绕形成卷绕结构。
在一些实施例中，卷绕结构具有平直区224，平直区224即为卷绕结构具有平直结构的区域，即在平直区224的负极极片221、正极极片222和隔离膜223基本平直且相互平行。可理解的，在平直区224中，每层负极极片221的表面、每层正极极片222的表面和每层隔离膜223的表面均为平面。
在平直区224的负极极片221与在平直区224的正极极片222在第一方向X上交替叠加，即在平直区224，在第一方向X上，以一层负极极片221、一层正极极片222、一层负极极片221的顺序依次排布。
在一些实施例中，卷绕结构还可以包括弯折区225，弯折区225与平直区224相连，可以是平直区224相对的两端均设有弯折区225。弯折 区225即为卷绕结构中具有弯折结构的区域，即在弯折区225内的负极极片221、正极极片222和隔离膜223均弯折。可理解的，在弯折区225中，每层负极极片221的表面、每层正极极片222的表面和每层隔离膜223的表面均为曲面，示例性的，该曲面为圆弧面。
在一些实施例中，请参照图6，图6为图5所示的正极极片222、隔离膜223和负极极片221展开后的局部视图，负极极片221包括负极集流体2211和涂覆于负极集流体2211的厚度方向上的两侧的负极活性物质体2212。正极极片222包括正极集流体2221和涂覆于正极集流体2221的厚度方向上的两侧的正极活性物质体2222。
在一些实施例中，请参照图7，图7为图5所示的电极组件22的A-A剖视图，负极极片221包括位于平直区224(参见图5)的负极活性物质层2213，正极极片222包括位于平直区224且与负极活性物质层2213在第一方向X相对设置的正极活性物质层2223，第一方向X垂直于卷绕结构的轴向Z。这里所指的第一方向X与负极活性物质层2213的厚度方向一致。
负极活性物质层2213包括负极主体部2213a和在轴向Z上位于负极主体部2213a的两侧的负极边缘部2213b，在第一方向X上，负极主体部2213a的至少部分和负极边缘部2213b的至少部分均与正极活性物质层2223重叠，负极主体部2213a的单位面积活性物质容量大于负极边缘部2213b的单位面积活性物质容量。
由于负极主体部2213a的单位面积活性物质容量大于负极边缘部2213b的单位面积活性物质容量，使得负极主体部2213a相较于负极边缘部2213b更不易出现析锂。在负极边缘部2213b的单位面积活性物质容量满足设置要求时，即负极边缘部2213b的单位面积活性物质容量达到第一预设值，由于负极主体部2213a的单位面积活性物质容量大于负极边缘部2213b的单位面积活性物质容量，即负极主体部2213a的单位面积活性物质容量大于第一预设值，相当于增大了负极主体部2213a的单位面积活性物质容量，增大了负极主体部2213a的CB(Cell Balance)值，提高了负极极片221中负极主体部2213a所在区域的耐膨胀力阈值，使得负极主体 部2213a不易出现析锂，从而降低了负极活性物质层2213在第一方向X上的中间区域出现析锂现象的风险。
需要说明的是，负极活性物质层2213即为负极极片221的负极活性物质体2212在平直区224的部分。负极活性物质体2212在平直区224的部分的结构与负极活性物质体2212在弯折区225的部分的结构可以相同，也可以不同。正极活性物质层2223即为正极极片222的正极活性物质体2222在平直区224的部分。正极活性物质体2222在平直区224的部分的结构与正极活性物质体2222在弯折区225的部分的结构可以相同，也可以不同。
在本申请实施例中，负极主体部2213a的CB(Cell Balance)值为Q1/Q2，Q1为负极主体部2213a的单位面积活性物质容量，Q2为正极活性物质层2223与负极主体部2213a在第一方向X重叠的部分的单位面积活性物质容量。
在一些实施例中，负极主体部2213a与负极边缘部2213b在轴向Z上连续分布，即负极极片221的负极活性物质层2213在轴向Z上不间断，有利于提高电池单体20的容量。当然，在其他实施例中，负极主体部2213a与负极边缘部2213b在轴向Z上也可以间隔分布。
在本申请实施例中，可通过多种方式实现负极主体部2213a的单位面积活性物质容量大于负极边缘部2213b的单位面积活性物质容量。
在一些实施例中，负极主体部2213a的活性材料的克容量大于负极边缘部2213b的活性材料的克容量。也就是说，可以通过增大负极主体部2213a的活性材料的克容量，来增大负极主体部2213a的单位面积活性物质容量，以实现负极主体部2213a的单位面积活性物质容量大于负极边缘部2213b的单位面积活性物质容量。
克容量是指活性材料所释放出的电容量与活性材料的质量之比。
在本实施例中，负极主体部2213a的厚度与负极边缘部2213b的厚度可以相等。负极主体部2213a的活性材料与负极边缘部2213b的活性材料可以不同，比如，负极主体部2213a的活性材料为硅，负极边缘部2213b的活性材料为石墨。
当然，也可以通过其他方式实现负极主体部2213a的单位面积活性物质容量大于负极边缘部2213b的单位面积活性物质容量。
在一些实施例中，负极主体部2213a的活性材料的重量与负极主体部2213a的重量的比值大于负极边缘部2213b的活性材料的重量与负极边缘部2213b的重量的比值。也就是说，可通过增大负极主体部2213a的活性材料的比重，来增大负极主体部2213a的单位面积活性物质容量，以实现负极主体部2213a的单位面积活性物质容量大于负极边缘部2213b的单位面积活性物质容量。
示例性的，负极主体部2213a和负极边缘部2213b的成分均可以包括活性材料、导电剂和粘接剂，负极主体部2213a的活性材料和负极边缘部2213b的活性材料可以相同。
在本申请实施例中，在负极主体部2213a的单位面积活性物质容量大于负极边缘部2213b的单位面积活性物质容量的情况下，正极活性物质层2223可以是多种结构。
在一些实施例中，正极活性物质层2223包括正极主体部2223a和轴向Z上位于正极主体部2223a的两侧的正极边缘部2223b，在第一方向X上，正极主体部2223a的至少部分和正极边缘部2223b的至少部分均与负极活性物质层2213重叠，正极主体部2223a的单位面积活性物质容量等于正极边缘部2223b的单位面积活性物质容量。
在另一些实施例中，请参照图8，图8为本申请一些实施例提供的电极组件22的局部剖视图，正极活性物质层2223包括正极主体部2223a和轴向Z上位于正极主体部2223a的两侧的正极边缘部2223b，在第一方向X上，正极主体部2223a的至少部分和正极边缘部2223b的至少部分均与负极活性物质层2213重叠，正极主体部2223a的单位面积活性物质容量小于正极边缘部2223b的单位面积活性物质容量。
正极主体部2223a的单位面积活性物质容量小于正极边缘部2223b的单位面积活性物质容量，使得负极活性物质层2213与正极主体部2223a重叠的部分相较于负极活性物质层2213与负极边缘部2213b重叠的部分更不易出现析锂。在正极边缘部2223b的单位面积活性物质容量满足 设置要求时，即正极边缘部2223b的单位面积活性物质容量达到第二预设值，由于正极主体部2223a的单位面积活性物质容量小于正极边缘部2223b的单位面积活性物质容量，即正极主体部2223a的单位面积活性物质容量小于第二预设值，相当于减小了正极主体部2223a的单位面积活性物质容量，增大了负极活性物质层2213与正极主体部2223a重叠的部分的CB值，提高了正极极片222中正极主体部2223a所在区域的耐膨胀力阈值，使得负极活性物质层2213与正极主体部2223a重叠的部分不易出现析锂，从而降低了负极活性物质层2213在第一方向X上的中间区域出现析锂现象的风险。
在一些实施例中，正极主体部2223a与正极边缘部2223b在轴向Z上连续分布，即正极极片222的正极活性物质层2223在轴向Z上不间断，有利于提高电池单体20的容量。当然，在其他实施例中，正极主体部2223a与正极边缘部2223b在轴向Z上也可以间隔分布。
在一些实施例中，在第一方向X上，负极主体部2213a的至少部分与正极主体部2223a的至少部分重叠，负极边缘部2213b的至少部分与正极边缘部2223b的至少部分重叠。
由于负极主体部2213a的单位面积活性物质容量大于负极边缘部2213b的单位面积活性物质容量，正极主体部2223a的单位面积活性物质容量小于正极边缘部2223b的单位面积活性物质容量，在第一方向X上，负极主体部2213a的至少部分与正极主体部2223a的至少部分重叠，负极主体部2213a更不易出现析锂，进一步降低了负极活性物质层2213在第一方向X上的中间区域出现析锂风险。
需要说明的是，在第一方向X上，负极主体部2213a的至少部分与正极主体部2223a的至少部分重叠，即负极主体部2213a在第一方向X上的投影与正极主体部2223a在第一方向X上的投影至少有一部分重叠；在第一方向X上，负极边缘部2213b的至少部分与正极边缘部2223b的至少部分重叠，即负极边缘部2213b在第一方向X上的投影与正极边缘部2223b在第一方向X上的投影至少有一部分重叠。
在一些实施例中，在第一方向X上，负极主体部2213a与正极主 体部2223a可以完全重叠。以进一步降低负极主体部2213a出现析锂风险。当然，在第一方向X上，负极边缘部2213b与正极边缘部2223b也可以完全重叠。
在本申请实施例中，也可以通过多种方式实现正极主体部2223a的单位面积活性物质容量小于正极边缘部2223b的单位面积活性物质容量。
在一些实施例中，请继续参照图8，正极主体部2223a的活性材料的克容量小于正极边缘部2223b的活性材料的克容量。也就是说，可通过减小正极主体部2223a的活性材料的克容量，来减小正极主体部2223a的单位面积活性物质容量，以实现正极主体部2223a的单位面积活性物质容量小于正极边缘部2223b的单位面积活性物质容量。
在本实施例中，正极主体部2223a的厚度与正极边缘部2223b的厚度可以相等，正极主体部2223a的活性材料与正极边缘部2223b的活性材料可以不同，比如，正极主体部2223a的活性材料为磷酸铁锂，正极边缘部2223b的活性材料为三元锂。
在一些实施例中，请参照图9，图9为本申请又一些实施例提供的电极组件22的局部剖视图，正极主体部2223a包括在第一方向X层叠设置的第一正极涂层2223c和第二正极涂层2223d。第一正极涂层2223c的活性材料的克容量小于或等于正极边缘部2223b的活性材料的克容量，第二正极涂层2223d的活性材料的克容量小于第一正极涂层2223c的活性材料的克容量，从而使得正极主体部2223a的活性材料的克容量小于正极边缘部2223b的活性材料的克容量，进而使正极主体部2223a的单位面积活性物质容量小于正极边缘部2223b的单位面积活性物质容量。
其中，第一正极涂层2223c可以是含有活性材料的活性物质层，也可以是不含活性材料的非活性物质层，比如，第一正极涂层2223c为金属导电层，其只起到导电作用。
示例性的，如图9所示，第一正极涂层2223c与第二正极涂层2223d的总厚度可以与正极边缘部2223b的厚度相等。第一正极涂层2223c的活性材料的克容量可以等于正极边缘部2223b的活性材料的克容 量，第一正极涂层2223c的活性材料与正极边缘部2223b的活性材料可以相同，第一正极涂层2223c的活性材料与第二正极涂层2223d的活性材料可以不同。
需要说明的是，第一正极涂层2223c和第二正极涂层2223d在第一方向X上层叠设置，可以是第一正极涂层2223c涂覆于正极集流体2221，第二正极涂层2223d涂覆于第一正极涂层2223c背离正极集流体2221的一侧，也可以是第二正极涂层2223d涂覆于正极集流体2221，第一正极涂层2223c涂覆于第二正极涂层2223d背离正极集流体2221的一侧。
当然，也可以通过其他方式实现正极主体部2223a的单位面积活性物质容量小于正极边缘部2223b的单位面积活性物质容量。
在一些实施例中，正极主体部2223a的活性材料的重量与正极主体部2223a的重量的比值小于正极边缘部2223b的活性材料的重量与正极边缘部2223b的重量的比值。也就是说，可通过减小正极主体部2223a的活性材料的比重，来减小正极主体部2223a的单位面积活性物质容量，以实现正极主体部2223a的单位面积活性物质容量小于正极边缘部2223b的单位面积活性物质容量。
示例性的，正极主体部2223a和正极边缘部2223b的成分均可以包括活性材料、导电剂和粘接剂，正极主体部2223a的活性材料和正极边缘部2223b的活性材料可以相同。
在另一些实施例中，请参照图10，图10为本申请再一些实施例提供的电极组件22的局部剖视图，正极主体部2223a的厚度小于正极边缘部2223b的厚度。
通过减小正极主体部2223a的厚度，使得正极主体部2223a的厚度小于正极边缘部2223b的厚度，同样可以实现正极主体部2223a的单位面积活性物质容量小于正极边缘部2223b的单位面积活性物质容量。此外，由于正极主体部2223a的厚度小于正极边缘部2223b的厚度，使得正极极片222在正极主体部2223a所在的区域厚度相对较薄，提高了该区域的耐膨胀力阈值，以降低析锂现象的发生。
在本实施例中，正极主体部2223a材料与正极边缘部2223b的材料相同。可以理解的，正极主体部2223a的成分与正极边缘部2223b的成分相同，且正极主体部2223a中的各成分所占比例与正极边缘部2223b中的各成分所占比例相同。比如，正极主体部2223a的成分和正极边缘部2223b的成分均包括活性材料、导电剂和粘接剂，正极主体部2223a的活性材料、导电剂和粘接剂与正极边缘部2223b的活性材料、导电剂和粘接剂相同，正极主体部2223a中的活性材料所占比例与正极边缘部2223b中的活性材料所占比例相同，正极主体部2223a中的导电剂所占比例与正极边缘部2223b中的导电剂所占比例相同，正极主体部2223a中的粘接剂所占比例与正极边缘部2223b中的粘接剂所占比例相同。
需要说明的是，在本申请实施例中，在正极活性物质层2223中的正极主体部2223a的单位面积活性物质容量小于正极边缘部2223b的单位面积活性物质容量情况下，负极活性物质层2213中的负极主体部2213a的单位面活性物质容量也可等于负极边缘部2213b的单位面活性物质容量。
请参照图11，图11为本申请一些实施例提供的电极组件22的制造方法的流程图，电极组件22的制造方法包括：
S100：提供负极极片221和正极极片222；
S200：将负极极片221和正极极片222层叠并卷绕形成卷绕结构；
其中，卷绕结构具有平直区224，负极极片221包括位于平直区224的负极活性物质层2213，正极极片222包括位于平直区224且与负极活性物质层2213在第一方向X相对设置的正极活性物质层2223，第一方向X垂直于卷绕结构的轴向Z。
负极活性物质层2213包括负极主体部2213a和在轴向Z上位于负极主体部2213a的两侧的负极边缘部2213b，在第一方向X上，负极主体部2213a的至少部分和负极边缘部2213b的至少部分均与正极活性物质层2223重叠，负极主体部2213a的单位面积活性物质容量大于负极边缘部2213b的单位面积活性物质容量；和/或，正极活性物质层2223包括正 极主体部2223a和在轴向Z上位于正极主体部2223a的两侧的正极边缘部2223b，在第一方向X上，正极主体部2223a的至少部分和正极边缘部2223b的至少部分均与负极活性物质层2213重叠，正极主体部2223a的单位面积活性物质容量小于正极边缘部2223b的单位面积活性物质容量。
在一些实施例中，请参照图12，图12为本申请又一些实施例提供的电极组件22的制造方法的流程图，还提供用于将正极极片222和负极极片221隔离的隔离膜223，将负极极片221、隔离膜223和正极极片222层叠并卷绕形成卷绕结构。
需要说明的是，通过上述实施例提供的电极组件22的制造方法制造出的电极组件22的相关结构，可参见上述各实施例提供的电极组件22。
请参照图13，图13为本申请一些实施例提供的电极组件22的制造设备2000的示意性框图，制造设备2000包括提供装置2100和组装装置2200，提供装置2100用于提供正极极片222和负极极片221，组装装置2200用于将负极极片221和正极极片222层叠并卷绕形成卷绕结构。
其中，卷绕结构具有平直区224，负极极片221包括位于平直区224的负极活性物质层2213，正极极片222包括位于平直区224且与负极活性物质层2213在第一方向X相对设置的正极活性物质层2223，第一方向X垂直于卷绕结构的轴向Z；
负极活性物质层2213包括负极主体部2213a和在轴向Z上位于负极主体部2213a的两侧的负极边缘部2213b，在第一方向X上，负极主体部2213a的至少部分和负极边缘部2213b的至少部分均与正极活性物质层2223重叠，负极主体部2213a的单位面积活性物质容量大于负极边缘部2213b的单位面积活性物质容量；和/或，正极活性物质层2223包括正极主体部2223a和在轴向Z上位于正极主体部2223a的两侧的正极边缘部2223b，在第一方向X上，正极主体部2223a的至少部分和正极边缘部2223b的至少部分均与负极活性物质层2213重叠，正极主体部2223a的单位面积活性物质容量小于正极边缘部2223b的单位面积活性物质容量。
在一些实施例中，提供装置2100还用于提供将正极极片222和负极极片221隔离的隔离膜223，并将负极极片221、隔离膜223和正极极片222层叠并卷绕形成卷绕结构。
需要说明的是，通过上述实施例提供的电极组件22的制造设备2000制造出的电极组件22的相关结构，可参见上述各实施例提供的电极组件22。
此外，本申请实施例还提供一种电极组件22的CB值测试方法，CB值测试步骤如下：
步骤1)：正极单面活性物质层的平均放电容量测试。取上述各实施例的正极极片，利用冲片模具获得含正极单面活性物质层的小圆片。以金属锂片为对电极，Celgard膜为隔离膜，溶解有LiPF6(1mol/L)的EC+DMC+DEC(体积比为1:1:1的碳酸乙烯酯、碳酸二甲酯、碳酸二乙酯)的溶液为电解液，在氩气保护的手套箱中组装6个相同的CR2430型扣式电池。①电池组装完后静置12h，②在0.1C的充电电流下进行恒流充电，直到电压到达上限截止电压x1V，然后保持电压x1V进行恒压充电，直到电流为50uA，③静置5min，④最后在0.1C的放电电流下进行恒流放电，直到电压到达下限截止电压y1V，⑤静置5min，重复2-5步骤，记录第2次循环的放电容量。6个扣式电池放电容量的平均值即为正极单面活性物质层的平均放电容量。例如，当正极活性材料为磷酸铁锂(LFP)时，上限截止电压x1V＝3.75V，下限截止电压y1V＝2V。当正极活性材料为锂镍钴锰氧化物(NCM)时，上限截止电压x1V＝4.25V，下限截止电压y1V＝2.8V。
步骤2)：负极单面活性物质层的平均充电容量测试。取上述各实施例的负极极片，利用冲片模具获得与上述步骤1)中正极小圆片面积相同且包含负极单面膜层的小圆片。以金属锂片为对电极，Celgard膜为隔离膜，溶解有LiPF6(1mol/L)的EC+DMC+DEC(体积比为1:1:1的碳酸乙烯酯、碳酸二甲酯、碳酸二乙酯)的溶液为电解液，在氩气保护的手套箱中组装6个CR2430型扣式电池。①电池组装完后静置12h，②在0.05C的放电电流下进行恒流放电，直到电压到达下限截止电压y2mV，③然后再 用50uA的放电电流进行恒流放电，直到电压达到下限截止电压y2mV，④静置5min，⑤接着用10uA的放电电流进行恒流放电，直到达到下限截止电压y2mV，⑥静置5分钟，⑦最后在0.1C的充电电流下进行恒流充电，直到最终电压达到上限截至电压x2V，⑧静置5分钟，重复2-8步骤，记录第2次循环的充电容量。6个扣式电池充电容量的平均值即为负极单面膜层的平均充电容量。例如，当负极活性材料为石墨时，上限截止电压x2V＝2V，下限截止电压y2V＝5mV。当负极活性材料为硅时，上限截止电压x2V＝2V，下限截止电压y2V＝5mV。
步骤3)：根据CB值＝上述负极单面活性物质层的平均充电容量(mAh)/上述正极单面活性物质层的平均放电容量(mAh)，计算得出CB值。
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。
以上实施例仅用以说明本申请的技术方案，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 (16)

  1. 一种电极组件，包括负极极片和正极极片，所述负极极片和所述正极极片层叠并卷绕形成具有平直区的卷绕结构，所述负极极片包括位于所述平直区的负极活性物质层，所述正极极片包括位于所述平直区且与所述负极活性物质层在第一方向相对设置的正极活性物质层，所述第一方向垂直于所述卷绕结构的轴向；
    所述负极活性物质层包括负极主体部和在所述轴向上位于负极主体部的两侧的负极边缘部，在所述第一方向上，所述负极主体部的至少部分和所述负极边缘部的至少部分均与所述正极活性物质层重叠，所述负极主体部的单位面积活性物质容量大于所述负极边缘部的单位面积活性物质容量；和/或，所述正极活性物质层包括正极主体部和在所述轴向上位于正极主体部的两侧的正极边缘部，在所述第一方向上，所述正极主体部的至少部分和所述正极边缘部的至少部分均与所述负极活性物质层重叠，所述正极主体部的单位面积活性物质容量小于所述正极边缘部的单位面积活性物质容量。
  2. 根据权利要求1所述的电极组件，其中，所述负极活性物质层包括所述负极主体部和所述负极边缘部，所述正极活性物质层包括所述正极主体部和所述正极边缘部；
    在所述第一方向上，所述负极主体部的至少部分与所述正极主体部的至少部分重叠，所述负极边缘部的至少部分与所述正极边缘部的至少部分重叠。
  3. 根据权利要求2所述的电极组件，其中，在所述第一方向上，所述负极主体部与所述正极主体部完全重叠。
  4. 根据权利要求1-3任一项所述的电极组件，其中，所述负极主体部 的活性材料的克容量大于所述负极边缘部的活性材料的克容量。
  5. 根据权利要求1-3任一项所述的电极组件，其中，所述负极主体部的活性材料的重量与所述负极主体部的重量的比值大于所述负极边缘部的活性材料的重量与所述负极边缘部的重量的比值。
  6. 根据权利要求1-5任一项所述的电极组件，其中，所述正极主体部的活性材料的克容量小于所述正极边缘部的活性材料的克容量。
  7. 根据权利要求6所述的电极组件，其中，所述正极主体部包括在所述第一方向层叠设置的第一正极涂层和第二正极涂层；
    所述第一正极涂层的活性材料的克容量小于或等于正极边缘部的活性材料的克容量，所述第二正极涂层的活性材料的克容量小于所述第一正极涂层的活性材料的克容量。
  8. 根据权利要求1-5任一项所述的电极组件，其中，所述正极主体部的活性材料的重量与所述正极主体部的重量的比值小于所述正极边缘部的活性材料的重量与正极边缘部的重量的比值。
  9. 根据权利要求1-5任一项所述的电极组件，其中，所述正极主体部的厚度小于所述正极边缘部的厚度。
  10. 根据权利要求1-9任一项所述的电极组件，其中，所述负极主体部与所述负极边缘部在所述轴向上连续分布。
  11. 根据权利要求1-10任一项所述的电极组件，其中，所述正极主体部与所述正极边缘部在所述轴向上连续分布。
  12. 一种电池单体，包括外壳和根据权利要求1-11任一项所述的电极组件；
    所述电极组件容纳于所述外壳内。
  13. 一种电池，包括箱体和根据权利要求12所述的电池单体，所述电池单体容纳于所述箱体内。
  14. 一种用电设备，包括根据权利要求13所述的电池。
  15. 一种电极组件的制造方法，包括：
    提供负极极片和正极极片；
    将所述负极极片和所述正极极片层叠并卷绕形成卷绕结构；
    其中，所述卷绕结构具有平直区，所述负极极片包括位于所述平直区的负极活性物质层，所述正极极片包括位于所述平直区且与所述负极活性物质层在第一方向相对设置的正极活性物质层，所述第一方向垂直于所述卷绕结构的轴向；
    所述负极活性物质层包括负极主体部和在所述轴向上位于负极主体部的两侧的负极边缘部，在所述第一方向上，所述负极主体部的至少部分和所述负极边缘部的至少部分均与所述正极活性物质层重叠，所述负极主体部的单位面积活性物质容量大于所述负极边缘部的单位面积活性物质容量；和/或，所述正极活性物质层包括正极主体部和在所述轴向上位于正极主体部的两侧的正极边缘部，在所述第一方向上，所述正极主体部的至少部分和所述正极边缘部的至少部分均与所述负极活性物质层重叠，所述正极主体部的单位面积活性物质容量小于所述正极边缘部的单位面积活性物质容量。
  16. 一种电极组件的制造设备，包括；
    提供装置，用于提供正极极片和负极极片；
    组装装置，用于将所述负极极片和所述正极极片层叠并卷绕形成卷绕结构；
    其中，所述卷绕结构具有平直区，所述负极极片包括位于所述平直区的负极活性物质层，所述正极极片包括位于所述平直区且与所述负极活性物质层在第一方向相对设置的正极活性物质层，所述第一方向垂直于所述卷绕结构的轴向；
    所述负极活性物质层包括负极主体部和在所述轴向上位于负极主体部的两侧的负极边缘部，在所述第一方向上，所述负极主体部的至少部分和所述负极边缘部的至少部分均与所述正极活性物质层重叠，所述负极主体部的单位面积活性物质容量大于所述负极边缘部的单位面积活性物质容量；和/或，所述正极活性物质层包括正极主体部和在所述轴向上位于正极主体部的两侧的正极边缘部，在所述第一方向上，所述正极主体部的至少部分和所述正极边缘部的至少部分均与所述负极活性物质层重叠，所述正极主体部的单位面积活性物质容量小于所述正极边缘部的单位面积活性物质容量。
PCT/CN2021/083434 2021-03-26 2021-03-26 电极组件、电池单体、电池及电极组件的制造方法和设备 WO2022198682A1 (zh)

Priority Applications (4)

Application Number Priority Date Filing Date Title
PCT/CN2021/083434 WO2022198682A1 (zh) 2021-03-26 2021-03-26 电极组件、电池单体、电池及电极组件的制造方法和设备
EP21809899.4A EP4089769B1 (en) 2021-03-26 2021-03-26 Electrode assembly, battery cell, battery, and method and device for manufacturing electrode assembly
CN202180006850.0A CN115413379B (zh) 2021-03-26 2021-03-26 电极组件、电池单体、电池及电极组件的制造方法和设备
US17/563,309 US20220311056A1 (en) 2021-03-26 2021-12-28 Electrode assembly, battery cell, battery, manufacturing method and device for electrode assembly

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2021/083434 WO2022198682A1 (zh) 2021-03-26 2021-03-26 电极组件、电池单体、电池及电极组件的制造方法和设备

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US17/563,309 Continuation US20220311056A1 (en) 2021-03-26 2021-12-28 Electrode assembly, battery cell, battery, manufacturing method and device for electrode assembly

Publications (1)

Publication Number Publication Date
WO2022198682A1 true WO2022198682A1 (zh) 2022-09-29

Family

ID=83365048

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/083434 WO2022198682A1 (zh) 2021-03-26 2021-03-26 电极组件、电池单体、电池及电极组件的制造方法和设备

Country Status (4)

Country Link
US (1) US20220311056A1 (zh)
EP (1) EP4089769B1 (zh)
CN (1) CN115413379B (zh)
WO (1) WO2022198682A1 (zh)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116230856B (zh) * 2023-05-08 2023-07-18 宁德时代新能源科技股份有限公司 正极极片、电池以及用电设备
CN116387450B (zh) * 2023-06-07 2023-10-27 宁德时代新能源科技股份有限公司 正极极片、电池和用电设备

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105453315A (zh) * 2013-08-02 2016-03-30 丰田自动车株式会社 二次电池
WO2017090219A1 (ja) * 2015-11-27 2017-06-01 パナソニックＩｐマネジメント株式会社 円筒形電池
CN110010902A (zh) * 2019-03-29 2019-07-12 宁德新能源科技有限公司 电极极片和包含所述电极极片的电化学装置
CN111755257A (zh) * 2019-03-27 2020-10-09 太阳诱电株式会社 电化学器件
CN111916844A (zh) * 2020-08-13 2020-11-10 东莞新能安科技有限公司 电化学装置及电子装置
CN212161994U (zh) * 2020-06-02 2020-12-15 宁德时代新能源科技股份有限公司 电极组件及其制造装置、电池、电池模块、电池组、使用电池的装置

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3999890B2 (ja) * 1998-09-10 2007-10-31 三洋電機株式会社 リチウム二次電池
JP4411690B2 (ja) * 1999-06-30 2010-02-10 パナソニック株式会社 リチウムイオン二次電池
CN1205687C (zh) * 2000-12-27 2005-06-08 三菱化学株式会社 锂二次电池
JP2007329077A (ja) * 2006-06-09 2007-12-20 Matsushita Electric Ind Co Ltd 非水電解質二次電池およびその製造方法
JP2009026703A (ja) * 2007-07-23 2009-02-05 Toyota Motor Corp 組電池の製造方法
JP2011070976A (ja) * 2009-09-28 2011-04-07 Toyota Motor Corp リチウムイオン二次電池、車両及び電池搭載機器
JP6048322B2 (ja) * 2013-06-07 2016-12-21 トヨタ自動車株式会社 リチウムイオン二次電池
JP6318918B2 (ja) * 2014-06-30 2018-05-09 株式会社豊田自動織機 蓄電装置及び蓄電装置の製造方法
CN108258193A (zh) * 2017-12-28 2018-07-06 湖南三迅新能源科技有限公司 一种负极片及其制备方法、锂离子电池

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105453315A (zh) * 2013-08-02 2016-03-30 丰田自动车株式会社 二次电池
WO2017090219A1 (ja) * 2015-11-27 2017-06-01 パナソニックＩｐマネジメント株式会社 円筒形電池
CN111755257A (zh) * 2019-03-27 2020-10-09 太阳诱电株式会社 电化学器件
CN110010902A (zh) * 2019-03-29 2019-07-12 宁德新能源科技有限公司 电极极片和包含所述电极极片的电化学装置
CN212161994U (zh) * 2020-06-02 2020-12-15 宁德时代新能源科技股份有限公司 电极组件及其制造装置、电池、电池模块、电池组、使用电池的装置
CN111916844A (zh) * 2020-08-13 2020-11-10 东莞新能安科技有限公司 电化学装置及电子装置

Also Published As

Publication number Publication date
CN115413379A (zh) 2022-11-29
EP4089769B1 (en) 2024-05-22
EP4089769A1 (en) 2022-11-16
CN115413379B (zh) 2024-01-12
US20220311056A1 (en) 2022-09-29

Similar Documents

Publication Publication Date Title
WO2022165688A1 (zh) 电极组件及其制造方法和制造系统、电池单体以及电池
EP4131631A1 (en) Electrode assembly, battery cell, battery and power-consuming apparatus
WO2022165728A1 (zh) 电极组件、电池单体、电池及电极组件的制造设备和方法
US20240055646A1 (en) Wound electrode assembly, battery cell, battery, and electrical device
WO2022198682A1 (zh) 电极组件、电池单体、电池及电极组件的制造方法和设备
US20230238540A1 (en) Electrode assembly, battery cell, battery, and method and device for manufacturing electrode assembly
US20220416232A1 (en) Electrode assembly, method and system for manufacturing same, battery cell, and battery
US20220320596A1 (en) Electrode assembly, manufacturing method and manufacturing system of same, battery cell, and battery
US20240088449A1 (en) Winding type electrode assembly, battery cell, battery and power consumption device
WO2023168954A1 (zh) 电芯、电芯的制造方法、电池单体、电池及用电设备
US20230123434A1 (en) Electrode Plate, Electrode Assembly, Battery Cell, Battery, and Electric Appliance
CN215299297U (zh) 电极组件、电池单体、电池以及用电装置
WO2022165727A1 (zh) 电极组件、电池单体、电池及电极组件的制造设备和方法
WO2022222092A1 (zh) 电极组件及其制造方法和制造系统、电池单体以及电池
WO2023221606A1 (zh) 集流体、极片、电极组件、电池单体、电池及用电装置
WO2024044883A1 (zh) 电极组件、电池单体、电池及用电装置
WO2024077557A1 (zh) 电池单体、电池及用电设备
WO2022165725A1 (zh) 电极组件、电池单体、电池及制造电极组件的方法和设备
WO2024082271A1 (zh) 电极组件、电池单体、电池及用电装置
WO2022226965A1 (zh) 电池单体、电池、用电设备及电池的制造方法和设备

Legal Events

Date Code Title Description
ENP Entry into the national phase

Ref document number: 2021809899

Country of ref document: EP

Effective date: 20211129

NENP Non-entry into the national phase

Ref country code: DE