WO2022126634A1 - 电极组件及其制造方法和制造系统、电池单体、电池及用电装置 - Google Patents

电极组件及其制造方法和制造系统、电池单体、电池及用电装置 Download PDF

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Publication number
WO2022126634A1
WO2022126634A1 PCT/CN2020/137717 CN2020137717W WO2022126634A1 WO 2022126634 A1 WO2022126634 A1 WO 2022126634A1 CN 2020137717 W CN2020137717 W CN 2020137717W WO 2022126634 A1 WO2022126634 A1 WO 2022126634A1
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WO
WIPO (PCT)
Prior art keywords
bending
segment
segments
pole piece
electrode assembly
Prior art date
Application number
PCT/CN2020/137717
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English (en)
French (fr)
Inventor
王红
刘江
刘晓梅
Original Assignee
宁德时代新能源科技股份有限公司
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Application filed by 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to PCT/CN2020/137717 priority Critical patent/WO2022126634A1/zh
Priority to EP20965648.7A priority patent/EP4075561B1/en
Priority to CN202080102169.1A priority patent/CN115699398A/zh
Publication of WO2022126634A1 publication Critical patent/WO2022126634A1/zh
Priority to US17/893,503 priority patent/US20220407118A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0583—Construction or manufacture of accumulators with folded construction elements except wound ones, i.e. folded positive or negative electrodes or separators, e.g. with "Z"-shaped electrodes or separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • H01M50/207—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape
    • H01M50/209—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape adapted for prismatic or rectangular cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H01M10/0404—Machines for assembling 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
    • H01M10/04—Construction or manufacture in general
    • H01M10/045—Cells or batteries with folded plate-like electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H01M10/0459—Cells or batteries with folded separator between plate-like 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/463—Separators, membranes or diaphragms characterised by their shape
    • H01M50/466—U-shaped, bag-shaped or folded
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/533—Electrode connections inside a battery casing characterised by the shape of the leads or tabs
    • 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
    • H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
    • 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 more particularly, to an electrode assembly, a manufacturing method and a manufacturing system thereof, a battery cell, a battery, and an electrical device.
  • 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 present application provides an electrode assembly, a manufacturing method and a manufacturing system thereof, a battery cell, a battery and an electrical device, which can reduce the risk of lithium precipitation and enhance the safety of the battery.
  • an embodiment of the present application provides an electrode assembly, which includes: a first pole piece, including a plurality of bent segments and a plurality of stacked first stacked segments, each bent segment is used to connect two Adjacent first lamination segments, the bending segment has a guide portion, and the guide portion is used to guide the bending segment to bend during production; a plurality of second pole pieces, the second pole pieces are opposite in polarity to the first pole piece and include the second lamination section, the second lamination section of each second pole piece is arranged between two adjacent first lamination sections; the isolation film is used to separate the first pole piece and the second pole piece, and the isolation film includes A plurality of isolation segments, each isolation segment is disposed between the adjacent first stack segment and the second stack segment.
  • the thickness of the first stacking segment is Da
  • the thickness of the second stacking segment is Dc
  • the thickness of the isolation segment is Ds
  • the dimension is w, and w, Da, Dc and Ds satisfy the relation: Dc+2Ds ⁇ w ⁇ 2 ⁇ (Dc+2Ds+Da).
  • the guide portion when the size w of the guide portion satisfies the relational expression Dc+2Ds ⁇ w ⁇ 2 ⁇ (Dc+2Ds+Da), the guide portion can guide the first pole piece to bend in a predetermined area, thereby improving the bending
  • the controllability and accuracy of the position reduce the risk of the first pole piece and the second pole piece deviating from the predetermined position and reduce the lithium precipitation; at the same time, the guide part can also reduce the stress concentration of the first active material layer on the bending section , provide enough space for the second lamination section and the isolation film, reduce the extrusion force exerted by the bending section on the second lamination section and the isolation film, and reduce the powder drop.
  • the guide portion is disposed along a first direction, and the first direction is perpendicular to the bending direction of the bending section.
  • the guide portion includes at least one aperture.
  • the opening can reduce the strength of the bending section and make the bending section easier to bend. By arranging openings, at least part of the first active material layer in the bending section is removed, so as to reduce the stress concentration of the first active material layer on the bending section, provide space for the second laminated section and the isolation film, and reduce the bending The squeezing force exerted by the bending section on the second lamination section and the isolation film reduces powder drop.
  • the openings extend through the bent segment.
  • the opening can be formed by punching the first pole piece, and the forming process is simple.
  • the through opening can also reduce the weight of the electrode assembly and improve the energy density of the electrode assembly.
  • the electrolyte can also pass through the opening and wet the second pole piece, thereby improving the wettability of the electrode assembly.
  • the bending section includes a plurality of sub-bending sections, and the sub-bending sections and the openings are alternately arranged along the first direction.
  • the size of the sub-bending segments along the first direction can be reduced, making each sub-bending segment easier to bend, and helping to guide the folding of the first pole piece.
  • the size of the opening along the first direction is L1
  • the size of the sub-bending segment along the first direction is L2, where 2 ⁇ L1/L2 ⁇ 40.
  • the guide portion includes a plurality of openings, and the plurality of openings are spaced apart.
  • the plurality of openings are spaced apart along the first direction. Increasing the number of openings can correspondingly increase the number of sub-bending sections, reduce the size of the sub-bending sections along the first direction, make each sub-bending section easier to bend, and help guide the folding of the first pole piece .
  • the apertures are circular, oval, racetrack or polygonal.
  • the corners of the polygon are rounded. The rounded corners can make the corners of the polygonal openings smoother, and can reduce burrs on the first pole piece when the openings are formed.
  • the dimension of the guide portion along the first direction is L3, and the dimension of the bending section along the first direction is L4, 0.5 ⁇ L3/L4 ⁇ 0.99. In this way, the bending effect of the bending section and the guiding effect of the guiding portion can be improved on the premise of reducing the risk of fracture of the bending section.
  • the dimension L4 of the bending section along the first direction is 200mm-1200mm.
  • the size L4 of the bending section is 200mm-1200mm, the bending effect of the bending section is better.
  • the plurality of bending sections include a first bending section and a second bending section, and the first bending section and the second bending section are respectively connected to two ends of the first laminated section along the second direction,
  • the distance L5 between the guide portion on the first bending segment and the guide portion on the second bending segment along the second direction is 80mm-200mm, and the second direction is perpendicular to the first direction and the stacking direction. Setting the value of L5 to 80mm-200mm can improve the forming effect of the electrode assembly.
  • the first pole piece is a negative pole piece
  • the second pole piece is a positive pole piece.
  • the first active material layer of the bending section can provide lithium intercalation space for lithium ions and reduce the risk of lithium precipitation.
  • the first pole piece includes a first current collector and a first active material layer disposed on the surface of the first current collector
  • the second pole piece includes a second current collector and a second current collector disposed on the surface of the second current collector active material layer.
  • the first active material layer of the first lamination section completely covers the second active material layer of the second lamination section.
  • the first active material layer of the first stacking section can provide a lithium intercalation space for the lithium ions deintercalated from the second active material layer, thereby reducing lithium deposition.
  • the first active material layer of the first stacking section exceeds the second active material layer of the second stacking section by at least 0.1 mm.
  • the first active material layer of the first stacking section can provide sufficient space for lithium intercalation for the lithium ions deintercalated from the second active material layer, thereby reducing the risk of lithium precipitation.
  • each first lamination segment has two opposite first edges, and after the bending segment is guided to be bent during production, the first edge of the two adjacent first lamination segments connected to the bending segment Edges are consistent.
  • an embodiment of the present application provides a battery cell, including: a case, having an accommodating cavity and an opening; at least one electrode assembly of the first aspect, accommodating in the accommodating cavity; and a cover plate for closing the case opening.
  • an embodiment of the present application provides a battery, including: a box body; and at least one battery cell of the second aspect, wherein the battery cell is accommodated in the box body.
  • embodiments of the present application provide an electrical device configured to receive power provided from the battery of the third aspect.
  • an embodiment of the present application provides a method for manufacturing an electrode assembly, which includes: providing a first pole piece, the first pole piece includes a plurality of bending segments and a plurality of first stacking segments, each bending segment It is used to connect two adjacent first lamination sections, and the bending section has a guiding part, and the guiding part is used to guide the bending of the bending section during production; an isolation film is provided, and the isolation film is fixed on the two sides of the first pole piece.
  • the isolation membrane includes a plurality of isolation segments; a plurality of second pole pieces are provided, the second pole pieces are opposite in polarity to the first pole pieces and include a second laminated segment, and the second pole pieces are fixed on the away from the isolation membrane
  • the surface of the first pole piece; the bending segment is bent under the guidance of the guide part, so that a plurality of first lamination segments are arranged in layers, and the second lamination segments of each second pole piece are arranged in two adjacent first Between the lamination segments, each isolation segment is disposed between adjacent first lamination segments and second lamination segments.
  • the thickness of the first stacking segment is Da
  • the thickness of the second stacking segment is Dc
  • the thickness of the isolation segment is Ds
  • the thickness of the guide portion in the bending direction of the bending segment is Ds.
  • the dimension is w, and w, Da, Dc and Ds satisfy the relation: Dc+2Ds ⁇ w ⁇ 2 ⁇ (Dc+2Ds+Da).
  • an embodiment of the present application provides a manufacturing system for an electrode assembly, including: a first providing device for providing a first pole piece, where the first pole piece includes a plurality of bending segments and a plurality of first lamination segments , each bending section is used to connect two adjacent first lamination sections, the bending section has a guiding part, and the guiding part is used to guide the bending of the bending section during production; the second providing device is used to provide an isolation film , the isolation membrane includes a plurality of isolation segments; the first assembly device is used to fix the isolation membrane on the two surfaces of the first pole piece; the third provision device is used to provide a plurality of second pole pieces, and the second pole piece is The first pole piece is opposite in polarity and includes a second lamination section; a second assembly device is used to fix the second pole piece on the surface of the isolation membrane facing away from the first pole piece; and a third assembly device is used in the guide part.
  • the bending segment is bent under the guidance, so that a plurality of first lamination segments are arranged in layers, the second lamination segment of each second pole piece is arranged between two adjacent first lamination segments, and each isolation segment is arranged in Between the adjacent first lamination segments and the second lamination segments; wherein, in the lamination direction of the plurality of first lamination segments, the thickness of the first lamination segment is Da, the thickness of the second lamination segment is Dc, and the thickness of the isolation segment is Dc.
  • the thickness is Ds
  • the dimension of the guide portion in the bending direction of the bending section is w
  • w, Da, Dc and Ds satisfy the relationship: Dc+2Ds ⁇ w ⁇ 2 ⁇ (Dc+2Ds+Da).
  • FIG. 1 is a schematic structural diagram of a vehicle according to an embodiment of the application.
  • FIG. 2 is a schematic structural diagram of a battery according to an embodiment of the application.
  • FIG. 3 is a schematic structural diagram of a battery module according to an embodiment of the present application.
  • FIG. 4 is a schematic structural diagram of a battery cell according to an embodiment of the present application.
  • FIG. 5 is a schematic front view of an electrode assembly according to an embodiment of the application.
  • FIG. 6 is a schematic cross-sectional view of the electrode assembly shown in FIG. 5 taken along line A-A;
  • FIG. 7 is a schematic cross-sectional view of the electrode assembly shown in FIG. 5 taken along line B-B;
  • FIG. 8 is an enlarged schematic view of the electrode assembly shown in FIG. 6 at block C;
  • FIG. 9 is a schematic structural diagram of a first pole piece of an electrode assembly in a folded state according to an embodiment of the application.
  • FIG. 10 is a schematic structural diagram of a first pole piece of an electrode assembly according to an embodiment of the present application in an unfolded state
  • FIG. 11 is a schematic structural diagram of a first pole piece of an electrode assembly according to another embodiment of the present application in an unfolded state
  • 12 to 16 are schematic diagrams of the electrode assembly in the forming process of an embodiment of the present application.
  • 17 is a partial cross-sectional schematic diagram of an electrode assembly according to an embodiment of the application.
  • FIG. 18 is a partial cross-sectional schematic diagram of an electrode assembly according to an embodiment of the application.
  • FIG. 19 is a schematic flowchart of a method for manufacturing an electrode assembly according to an embodiment of the present application.
  • FIG. 20 is a schematic block diagram of a system for manufacturing a battery cell according to an embodiment 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.
  • multiple refers to two or more (including two), and similarly, “multiple groups” refers to two or more groups (including two groups), and “multiple sheets” refers to two or more sheets (includes two pieces).
  • parallel includes not only the case of absolute parallelism, but also the case of being approximately parallel in the conventional knowledge in engineering; meanwhile, the term “perpendicular” also includes not only the case of absolute perpendicularity, but also the case of being approximately parallel in the conventional knowledge in engineering. vertical case.
  • 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-shaped 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 pole piece, a negative pole piece and a separator.
  • the battery cell mainly relies on the movement of metal ions between the positive pole piece and the negative pole piece to work.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, the positive electrode active material layer is coated on the surface of the positive electrode current collector, and the current collector without the positive electrode active material layer protrudes from the current collector coated with the positive electrode active material layer, The current collector not coated with the positive electrode active material layer was 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 pole piece includes a negative electrode current collector and a negative electrode active material layer, the negative electrode active material layer is coated on the surface of the negative electrode current collector, and the current collector without the negative electrode active material layer is protruded from the current collector that has been coated with the negative electrode active material layer, The current collector not coated with the negative electrode active material layer was 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 separator has a large number of through-holes, which can ensure the free passage of electrolyte ions and have good permeability to lithium ions.
  • the material of the separator can be PP or PE, etc.
  • lithium ions are deintercalated from the positive electrode and embedded in the negative electrode, but some abnormal conditions may occur, such as insufficient space for lithium insertion in the negative electrode, too much resistance for lithium ions to be inserted into the negative electrode, or too fast lithium ions.
  • the de-intercalated lithium ions cannot be embedded in the negative active material layer of the negative electrode pole piece in an equal amount, and the lithium ions that cannot be embedded in the negative electrode pole piece can only obtain electrons on the surface of the negative electrode, thereby forming silver-white metallic lithium element. It is the phenomenon of lithium precipitation.
  • Lithium precipitation not only reduces the performance of lithium-ion batteries and greatly shortens the cycle life, but also limits the fast charge capacity of lithium-ion batteries.
  • the precipitated lithium metal is very active, and can react with the electrolyte at a lower temperature, resulting in a decrease in the starting temperature (Tonset) of the battery's self-generated heat and self-generated heat. The heat rate increases, which seriously endangers the safety of the battery.
  • Tonset starting temperature
  • the deintercalated lithium ions can form lithium crystals on the surface of the negative electrode, and the lithium crystals easily pierce the separator, resulting in the risk of short circuit between the adjacent positive and negative electrodes.
  • the inventor After noticing the problem of poor electrochemical performance of the existing battery cells, the inventor found that at least one of the positive pole piece and the negative pole piece in the formed electrode assembly deviates from a predetermined position, thus affecting the electrode assembly. electrochemical performance. The inventors further found that at least one of the positive pole piece and the negative pole piece in the formed electrode assembly deviates from a predetermined position, resulting in lithium deposition in the electrode assembly, thereby affecting the electrochemical performance of the secondary battery. It is speculated that the reason may be that the negative electrode active material layer cannot completely cover the positive electrode active material layer, resulting in that the deintercalated lithium ions cannot be embedded in the negative electrode active material layer of the negative electrode electrode sheet in an equal amount.
  • the present application intends to provide an electrode assembly, which can keep the positive electrode and the negative electrode in a predetermined position, reduce the risk of lithium precipitation, ensure that the electrode assembly has good electrochemical performance, and improve the safety of the battery.
  • the technical solutions described in the embodiments of this application are applicable to various devices using batteries, such as mobile phones, portable devices, notebook computers, battery cars, electric toys, electric tools, electric vehicles, ships, and spacecraft.
  • the spacecraft includes Planes, rockets, space shuttles and spaceships, etc.
  • the vehicle 1 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or Extended range cars, etc.
  • a battery 10 , a controller 20 and a motor 30 may be provided inside the vehicle 1 , and the controller 20 is used to control the battery 10 to supply power to the motor 30 .
  • the battery 10 may be provided at the bottom of the vehicle 1 or at the front or rear of the vehicle.
  • the battery 10 can be used for power supply of the vehicle 1 , for example, the battery 10 can be used as the operating power source of the vehicle 1 , for the circuit system of the vehicle 1 , for example, for the starting, navigation and operation power requirements of the vehicle 1 .
  • the battery 10 can not only be used as the operating power source of the vehicle 1 , but also can be used as the driving power source of the vehicle 1 to provide driving power for the vehicle 1 in place of or partially in place of fuel or natural gas.
  • the battery 10 may include a plurality of battery cells, wherein the plurality of battery cells may be connected in series or in parallel or in a mixed connection, and a mixed connection refers to a mixture of series and parallel connection.
  • the battery 10 may also be referred to as a battery pack.
  • a plurality of battery cells can be connected in series or in parallel or mixed to form a battery module, and then a plurality of battery modules can be connected in series or in parallel or mixed to form the battery 10 . That is to say, a plurality of battery cells can directly form the battery 10 , or a battery module can be formed first, and then the battery module can form the battery 10 .
  • the battery 10 may include a plurality of battery cells 40 .
  • the battery 10 may further include a box body (or a cover body), the inside of the box body is a hollow structure, and the plurality of battery cells 40 are accommodated in the box body.
  • the box body may include two parts, which are referred to as the first part 111 and the second part 112 respectively, and the first part 111 and the second part 112 are fastened together.
  • the shapes of the first part 111 and the second part 112 may be determined according to the combined shape of the plurality of battery cells 40 , and each of the first part 111 and the second part 112 may have an opening.
  • both the first part 111 and the second part 112 can be a hollow cuboid and each has only one surface that is an open surface, the opening of the first part 111 and the opening of the second part 112 are arranged opposite to each other, and the first part 111 and the second part 112 are interlocked with each other Combined to form a box with a closed chamber.
  • the plurality of battery cells 40 are connected in parallel or in series or in a mixed connection, and then placed in the box formed after the first part 111 and the second part 112 are fastened together.
  • the battery 10 may also include other structures, which will not be repeated here.
  • the battery 10 may further include a bussing component for realizing electrical connection between a plurality of battery cells 40 , such as parallel or series or hybrid.
  • the bus member may realize electrical connection between the battery cells 40 by connecting the electrode terminals of the battery cells 40 .
  • the bus members may be fixed to the electrode terminals of the battery cells 40 by welding. The electrical energy of the plurality of battery cells 40 can be further drawn out through the case through the conductive mechanism.
  • the conducting means may also belong to the bussing member.
  • the number of battery cells 40 can be set to any value.
  • a plurality of battery cells 40 can be connected in series, in parallel or in a mixed connection to achieve larger capacity or power. Since the number of battery cells 40 included in each battery 10 may be large, in order to facilitate installation, the battery cells 40 may be arranged in groups, and each group of battery cells 40 constitutes a battery module.
  • the number of battery cells 40 included in the battery module is not limited, and can be set according to requirements.
  • FIG. 3 is an example of a battery module.
  • the battery 10 may include a plurality of battery modules, and the battery modules may be connected in series, parallel, or mixed.
  • FIG. 4 it is a schematic structural diagram of a battery cell 40 according to an embodiment of the present application.
  • the battery cell 40 of the embodiment of the application includes an electrode assembly 50 , a case 60 and an end cap assembly 70 .
  • the case 60 has an accommodating cavity and an opening, and the electrode assembly 50 is accommodated in the accommodating cavity.
  • the casing 60 is determined according to the combined shape of one or more electrode assemblies 50.
  • the casing 60 can be a hollow cuboid, a square or a cylinder, and one of the faces of the casing 60 has an opening for one or more electrode assemblies. 50 may be placed within housing 60 .
  • the casing 60 when the casing 60 is a hollow cuboid or cube, one of the planes of the casing 60 is an open surface, that is, the plane does not have a wall, so that the casing 60 communicates with the inside and the outside.
  • the end cap assembly 70 includes a cover plate 71, which covers the opening and is connected to the casing 60, thereby closing the opening of the casing 60, so that the electrode assembly 50 is placed in the closed cavity.
  • the casing 60 is filled with an electrolyte, such as an electrolytic solution.
  • the end cap assembly 70 may further include two electrode terminals 72 , and the two electrode terminals 72 may be disposed on the cover plate 71 .
  • the cover plate 71 is generally in the shape of a flat plate, and two electrode terminals 72 are fixed on the flat surface of the cover plate 71 , and the two electrode terminals 72 are respectively a positive electrode terminal and a negative electrode terminal.
  • Each electrode terminal 72 is correspondingly provided with a connecting member 73 , or it can also be called a current collecting member, which is used to electrically connect the electrode assembly 50 and the electrode terminal 72 .
  • Each electrode assembly 50 has a first tab 513 and a second tab 523 .
  • the polarities of the first tab 513 and the second tab 523 are opposite.
  • the first tab 513 is a positive tab
  • the second tab 523 is a negative tab.
  • the first tabs 513 of one or more electrode assemblies 50 are connected to one electrode terminal 72 through one connecting member 73
  • the second tabs 523 of one or more electrode assemblies 50 are connected to another electrode terminal 72 through another connecting member 73 . connect.
  • the positive electrode terminal is connected to the positive electrode tab through one connection member 73
  • the negative electrode terminal is connected to the negative electrode tab through the other connection member 73 .
  • the electrode assembly 50 can be provided in a single or a plurality of electrodes according to actual use requirements.
  • FIG. 5 is a schematic front view of an electrode assembly 50 according to an embodiment of the application
  • FIG. 6 is a schematic cross-sectional view of the electrode assembly 50 shown in FIG. 5 taken along the line A-A
  • FIG. 7 is the electrode assembly shown in FIG. 5 50 is a schematic cross-sectional view taken along the line B-B
  • FIG. 8 is an enlarged schematic view of the electrode assembly 50 shown in FIG. 6 at block C.
  • the electrode assembly 50 of the embodiment of the present application includes a first pole piece 51 , a second pole piece 52 and an isolation film 53 , and the isolation film 53 is used to separate the first pole piece 51 and the second pole piece 52 separated.
  • the polarity of the second pole piece 52 is opposite to that of the first pole piece 51.
  • the first pole piece 51 is a negative pole piece
  • the second pole piece 52 is a positive pole piece
  • the first pole piece 51 is a positive pole piece
  • the second pole piece 52 is a negative pole piece.
  • the first pole piece 51 includes a first current collector 51a and a first active material layer 51b disposed on the surface of the first current collector 51a.
  • the first current collector 51a includes a first coating region and a first protruding region, the first coating region is coated with the first active material layer 51b, the first protruding region protrudes from the first coating region, and the first The protruding area is at least partially uncoated with the first active material layer 51b.
  • the portion of the first protruding area that is not coated with the first active material layer 51 b is used for connection to the connecting member 73 , that is, the first protruding area serves as the first tab 513 .
  • the second pole piece 52 includes a second current collector 52a and a second active material layer 52b disposed on the surface of the second current collector 52a.
  • the second current collector 52a includes a second coating region and a second protruding region, the second coating region is coated with the second active material layer 52b, the second protruding region protrudes from the second coating region, and the second The protruding regions are at least partially uncoated with the second active material layer 52b.
  • the portion of the second protruding area where the second active material layer 52 b is not coated is used for connection to the connecting member 73 , that is, the second protruding area serves as the second tab 523 .
  • the first tab 513 and the second tab 523 are generally formed through a cutting process.
  • the second pole piece 52 further includes a protective coating 52c, the protective coating 52c is coated on the surface of the second current collector 52a and connected to the second active material layer 52b, and the protective coating 52c is located on the second active material The side of the layer 52b close to the second protruding area. A part of the protective coating 52c is coated on the second coating area, and another part of the protective coating 52c is coated on the second protruding area. The area of the second protruding area that is not covered by the protective coating 52c is used for connection to the connecting member 73 .
  • the protective coating 52c can reduce burrs at the cutting position during the cutting process of the second tab 523 .
  • the first pole piece 51 includes a plurality of bent segments 511 and a plurality of stacked first stacked segments 512 , and each bent segment 511 is used to connect two adjacent first stacked segments 512 .
  • the first pole piece 51 is a continuous extending structure as a whole, and is generally zigzag reciprocating bending.
  • the plurality of first stacking segments 512 are sequentially stacked along the stacking direction Z.
  • the bent section 511 is at least partially in a bent state.
  • the bent section 511 is in a bent state as a whole, and the bent section 511 is generally arc-shaped, such as a circular arc.
  • the bending section 511 is only partially in the bending state; specifically, the bending section 511 has an arc-shaped area 5111 and a straight area 5112, and the arc-shaped area 5111 is bent into an arc shape as a whole, such as a circular arc.
  • the flat region 5112 is flat and connects the arc region 5111 and the first lamination section 512.
  • the first lamination segment 512 is a flat plate as a whole and is perpendicular to the lamination direction Z. In other embodiments, the end of the first laminated segment 512 connected to the bending segment 511 may also be in a bent state.
  • a plurality of second pole pieces 52 are arranged.
  • Each second pole piece 52 includes a second laminated segment 522 , and the second laminated segment 522 of each second pole piece 52 is disposed between two adjacent first laminated segments 512 .
  • the plurality of second pole pieces 52 are separated from each other.
  • the second lamination section 522 is generally flat and perpendicular to the lamination direction Z, which is parallel to the thickness direction of the first lamination section 512 and the thickness direction of the second lamination section 522 .
  • the isolation film 53 includes a plurality of isolation segments 531 , and each isolation segment 531 is disposed between the adjacent first laminated segment 512 and the second laminated segment 522 .
  • the isolation segment 531 can insulate the adjacent first stack segment 512 and the second stack segment 522 apart to reduce the risk of short circuits.
  • the isolation section 531 is parallel to the first lamination section 512 and the second lamination section 522, and the thickness direction of the isolation section 531 is parallel to the lamination direction Z.
  • the isolation film 53 further includes connecting segments 532 disposed on the inner and outer sides of each bending segment 511 , and the connecting segments 532 are used to connect the two isolation segments 531 .
  • the connecting section 532 can insulate and separate the bending section 511 and the second laminated section 522 to reduce the risk of short circuit.
  • there are two isolation films 53 and each isolation film 53 is bent back and forth in a zigzag shape to form an isolation segment 531 and a connection segment 532 .
  • the first tab 513 extends from the edge of the first laminated segment 512
  • the second tab 523 extends from the edge of the second laminated segment 522 .
  • the number of the first tabs 513 and the number of the first stacked segments 512 are the same, and the first tabs 513 and the first stacked segments 512 are arranged in a one-to-one correspondence.
  • the number of the second tabs 523 is the same as the number of the second stacked segments 522 , and the second tabs 523 and the second stacked segments 522 are arranged in a one-to-one correspondence.
  • the inventor By analyzing the forming process of the electrode assembly, the inventor further studied the lithium deposition phenomenon and found that the first pole piece is a continuous structure as a whole, and it is difficult to bend along the predetermined area during the bending process, resulting in the first pole piece and the After the second pole piece is stacked to form an electrode assembly, there is a situation that the negative electrode active material layer cannot completely cover the positive electrode active material layer, which easily leads to lithium deposition in the electrode assembly, thereby affecting the electrochemical performance and safety performance of the secondary battery. In addition, when the first pole piece is bent, the first active material layer on the bending section will generate stress concentration, causing the active material to fall off, which is called the phenomenon of powder falling.
  • the space between the bending section and the second stacking section is limited, so the bending section may squeeze the edge of the second stacking section, which will also cause the second active material layer on the second stacking section to fall off; At the same time, the bent section may also squeeze the isolation membrane, resulting in a wrinkling of the isolation membrane between the bent section and the second laminate section.
  • the inventors improved the structure of the first pole piece.
  • the bending section 511 has a guiding portion 514, and the guiding portion 514 is used to guide the bending section 511 to be bent during production.
  • the guide portion 514 can guide the first pole piece 51 to bend in a predetermined area to form the bending section 511, Therefore, it is beneficial to improve the controllability and accuracy of the bending position, thereby reducing the risk that the first pole piece 51 and the second pole piece 52 deviate from the predetermined position, and reducing the negative electrode activity in the first stacking section 512 and the second stacking section 522.
  • the possibility that the material layer cannot completely cover the positive electrode active material layer reduces lithium deposition and improves the electrochemical performance of the electrode assembly 50 .
  • the number of the guiding parts 514 may be the same as the number of the bending segments 511 , and the guiding parts 514 and the bending segments 511 are provided in a one-to-one correspondence. Certainly, in some other embodiments, some of the bending segments 511 of all the bending segments 511 are provided with the guiding parts 514 , while other bending segments 511 may not be provided with the guiding parts 514 .
  • the guide portion 514 may be a trace left by things.
  • the guide portion 514 may refer to a structure formed by removing part of the first active material layer 51b on the first pole piece 51 by a material removal member, or the guide portion 514 may refer to a structure formed by removing a portion of the first active material layer 51b on the first pole piece 51 by a material removal member.
  • the first active material layer 51b itself has a certain degree of brittleness, and there is a possibility of powder falling due to stress concentration during the bending process.
  • the guide portion 514 is provided on the bending section 511, which can also provide space for the second lamination section 522 and the isolation film 53, reduce the extrusion force exerted by the bending section 511 on the second lamination section 522 and the isolation film 53, and reduce the powder drop. .
  • the bent segment 511 extends between two adjacent first laminated segments 512 .
  • the bending section 511 is parallel to the first direction X, and the first direction X is perpendicular to the stacking direction Z.
  • the bending section 511 extends along the bending direction S shown in the figure, and the bending direction S can be understood as a direction parallel to the surface of the bending section 511 .
  • the bending direction S is perpendicular to the first direction X.
  • the guide portion 514 is beneficial to improve the controllability and accuracy of the bending position, thereby reducing the risk that the first pole piece 51 and the second pole piece 52 deviate from the predetermined positions.
  • the inventor further found that the size of the guide portion 514 along the bending direction S has a direct impact on the bending position of the first pole piece 51 .
  • the guiding function of the guide portion 514 is limited, which will increase the fact that the first pole piece 51 is not in the predetermined direction.
  • the possibility of bending the area creates a risk that the first laminated segment 512 will deviate from the predetermined position.
  • the role of the guide portion 514 in reducing the stress concentration of the first active material layer 51b in the bent section 511 is not obvious, and the bent section 511 still has the risk of powder falling.
  • the space provided by the guide portion 514 for the second lamination section 522 and the isolation film 53 is too small, the pressing force exerted by the bending section 511 on the second lamination section 522 and the isolation film 53 is too large, and the second lamination section 522 still has powder falling off. risk.
  • the guide portion 514 along the bending direction S is too large, the easy bending area of the first pole piece 51 is too large, which also increases the probability that the first pole piece 51 is not bent in the predetermined area, resulting in the first pole piece 51 not being bent in the predetermined area. There is a risk of the lamination segment 512 deviating from the predetermined position, resulting in severe deformation of the electrode assembly 50 . Meanwhile, if the dimension of the guide portion 514 along the bending direction S is too large, the guide portion 514 may extend to the side of the second pole piece 52 along the stacking direction Z. At this time, the guide portion 514 cannot be removed for the first pole piece 51 The intercalated lithium ions provide space for intercalation of lithium, leading to the risk of lithium precipitation.
  • the inventor further improved the structure of the first pole piece 51 .
  • the thickness of the first stacking segment 512 is Da
  • the thickness of the second stacking segment 522 is Dc
  • the thickness of the isolation segment 531 is Ds
  • the dimension of the guide portion 514 in the bending direction S is w.
  • w, Da, Dc and Ds satisfy the relational expression: Dc+2Ds ⁇ w ⁇ 2 ⁇ (Dc+2Ds+Da).
  • the value of Da is 0.11 mm-0.25 mm
  • the value of Dc is 0.16 mm-0.3 mm
  • the value of Ds is 0.009 mm-0.02 mm.
  • the guide portion 514 can guide the first pole piece 51 to bend in a predetermined area, improve the controllability and accuracy of the bending position, and reduce the The risk of the first pole piece 51 and the second pole piece 52 deviating from the predetermined position reduces the lithium precipitation; at the same time, the guide portion 514 can also reduce the stress concentration of the first active material layer 51b on the bending section 511, which is the second stack
  • the section 522 and the isolation film 53 provide enough space to reduce the pressing force exerted by the bending section 511 on the second laminated section 522 and the isolation film 53, thereby reducing powder drop.
  • the size of the bent section 511 is associated with the size w of the guide portion 514 .
  • the dimension w of the guide portion 514 is equal to the dimension of the bending segment 511 . That is, the bending section 511 and the first stacking section 512 may be defined according to the edge of the guide portion 514 in the bending direction S.
  • the first pole piece 51 is a negative pole piece
  • the second pole piece 52 is a positive pole piece.
  • the first active material layer 51b of the bending section 511 can provide a lithium intercalation space for lithium ions, thereby reducing the risk of lithium precipitation.
  • the first active material layer 51b of the first lamination segment 512 completely covers the second active material layer 52b of the second lamination segment 522 .
  • “completely covering” means that in a plane perpendicular to the stacking direction Z, the orthographic projection of the second active material layer 52b of the second stacking section 522 is completely located on the first active material layer 51b of the first stacking section 512 Within the orthographic projection of , at this time, the projected area of the second active material layer 52 b of the second stacking segment 522 is smaller than the projected area of the first active material layer 51 b of the first stacking segment 512 .
  • the first active material layer 51b of the first stacking section 512 can provide a lithium intercalation space for the lithium ions deintercalated from the second active material layer 52b, thereby reducing lithium deposition.
  • the first active material layer 51b of the first stacking segment 512 protrudes beyond the second active material layer of the second stacking segment 522 by at least 0.1 mm.
  • the first active material layer 51b of the first stacking section 512 exceeds the second active material layer of the second stacking section 522 by at least 0.1 mm; in the second direction Y, the first stacking section 512 The first active material layer 51b is at least 0.1 mm beyond the second active material layer of the second stacking section 522 .
  • the second direction Y is perpendicular to the first direction X and the stacking direction Z. At this time, the first active material layer 51b of the first stack segment 512 can provide sufficient space for lithium intercalation for the lithium ions deintercalated from the second active material layer 52b, thereby reducing lithium precipitation.
  • FIG. 9 is a schematic structural diagram of the first pole piece 51 of the electrode assembly 50 according to an embodiment of the application in a folded state
  • FIG. 10 is a structure of the first pole piece 51 of the electrode assembly 50 according to an embodiment of the application in an unfolded state Schematic.
  • the dotted line in FIG. 10 does not represent a solid structure, but schematically shows the dividing line between the bending segment 511 and the first stack segment 512 .
  • the first pole piece 51 When the first pole piece 51 is in the unfolded state, the first pole piece 51 extends along its own length direction H, and the first laminated segments 512 and the bending segments 511 are alternately arranged along the length direction H. Each bent segment 511 connects two adjacent first stacked segments 512 .
  • the dimension w of the guide portion 514 along the bending direction S is the dimension w of the guide portion 514 along the length direction H when the first pole piece 51 is unfolded.
  • the first direction X is parallel to the width direction of the first pole piece 51 itself.
  • the guide portion 514 includes at least one aperture 514a.
  • an opening 514 a is formed on the bent segment 511 .
  • the opening 514a can reduce the strength of the bending section 511 and make the bending section 511 easier to bend.
  • By arranging the opening 514a at least part of the first active material layer of the bending section 511 is removed, so as to reduce the stress concentration of the first active material layer on the bending section 511, and provide space for the second lamination section and the isolation film, The pressing force exerted by the bending section 511 on the second lamination section and the isolation film is reduced to reduce powder falling.
  • the opening 514a may be a blind hole; in other words, the opening 514a is a groove that does not penetrate through the bent section 511 .
  • the apertures 514a are recessed relative to a surface of the bent segment 511 facing the second lamination segment.
  • the opening 514a is formed by removing part of the first active material layer, and the opening 514a extends to the first current collector and exposes the first current collector.
  • the opening 514a is a through hole and passes through the bending section 511 .
  • the opening 514a penetrates the first current collector of the bent section 511 and the first active material layers on both sides of the first current collector.
  • the opening 514a can be formed by punching the first pole piece 51, and the forming process is simple.
  • the through holes 514a can reduce the stress concentration of the first active material layer on the bending section 511, provide sufficient space for the second laminated section and the isolation film, and reduce the bending section 511 exerted on the second laminated section and the isolation film. squeeze force to reduce powder drop.
  • the through openings 514a can also reduce the weight of the electrode assembly and improve the energy density of the electrode assembly.
  • the electrolyte can also pass through the opening 514a and wet the second pole piece, thereby improving the wettability of the electrode assembly.
  • the bending section 511 includes a plurality of sub-bending sections 511a, and the sub-bending sections 511a and the openings 514a are alternately arranged along the first direction X.
  • Each sub-bending segment 511a connects two adjacent first stacked segments 512 .
  • the bending section 511 When the opening 514a is a through hole, the plurality of sub-bending segments 511a are separated from each other.
  • the bending section 511 further includes a sub-connecting section, the sub-connecting section is the bottom wall of the opening 514a, and the sub-connecting section connects two adjacent sub-bending sections 511a.
  • the dimension of the opening 514a along the first direction X is L1
  • the dimension of the sub-bending segment 511a along the first direction X is L2.
  • the size of the first pole piece 51 along the first direction X is constant.
  • the strength of the sub-bending section 511a is The lower the value, the easier it is to break during the bending process; on the contrary, the smaller the value of L1, the larger the value of L2, the more difficult the sub-bending section 511a is to bend, and the more the guiding effect of the sub-bending section 511a is. Difference.
  • the inventor has comprehensively considered the bending effect and strength of the sub-bending section 511a. After research and testing, it is found that when 2 ⁇ L1/L2 ⁇ 40, the sub-bending section 511a can be prevented from breaking under the premise that the sub-bending section can be improved. Bending effect of segment 511a.
  • the values of L1/L2 are 10, 20 and 30.
  • the guide portion 514 includes a plurality of openings 514a, and the plurality of openings 514a are arranged at intervals.
  • the plurality of openings 514a are arranged along the first direction X at intervals. Increasing the number of openings 514a can correspondingly increase the number of sub-bending sections 511a, reduce the size of the sub-bending sections 511a along the first direction X, make each sub-bending section 511a easier to bend, and help guide the first Folding of a pole piece 51 .
  • the apertures 514a are circular, oval, racetrack, or polygonal.
  • the above-mentioned shape refers to the shape of the opening 514a when the first pole piece 51 is in the unfolded state.
  • the corners of the polygonal openings 514a are rounded; the rounded corners can make the corners of the polygonal openings 514a smoother, which can reduce burrs on the first pole piece 51 when the openings 514a are formed.
  • the opening 514a is substantially rectangular and four corners are rounded.
  • the dimension of the guide portion 514 along the first direction X is L3. Specifically, when the guide portion 514 includes only one opening 514a, L3 is equal to L1. When the guide portion 514 includes a plurality of openings 514a, L3 is equal to the sum of the dimensions L1 of the plurality of openings 514a along the first direction X. As shown in FIG.
  • the dimension of the bending section 511 along the first direction X is L4.
  • the dimension L4 of the bent segment 511 along the first direction X is equal to the dimension of the first laminated segment 512 along the first direction X.
  • Each of the first lamination segments 512 has two opposite first edges 5121 , and the first edges 5121 are located at both ends of the first lamination segment 512 along the first direction X. In the first direction X, the distance between the two first edges 5121 is equal to L4.
  • the value of L4 is the width of the first pole piece 51 .
  • the dimension L4 of the bent segment 511 is equal to the sum of the dimension L1 of all the openings 514a and the dimension L2 of all the sub-bend segments 511a.
  • the L3/L4 values are 0.6, 0.7, 0.8 and 0.9.
  • the plurality of bending sections 511 include a first bending section and a second bending section, and the first bending section and the second bending section are respectively connected to the first laminated section 512 along the second direction Y
  • the distance L5 between the guide portion 514 on the first bending segment and the guide portion 514 on the second bending segment along the second direction Y is 80mm-200mm
  • the second direction Y is perpendicular to the first direction X and the stacking direction. Z.
  • the distance between the guide portions 514 of the two adjacent bending segments 511 along the length direction H of the first pole piece 51 is L5 .
  • the value of L5 is equal to the dimension of the first lamination segment 512 along the second direction Y.
  • the first laminated section 512 connected to the bending section 511 may be deflected.
  • a certain angle is formed between the first edge 5121 of the first laminated segment 512 and the second direction Y, and the larger the value of L5 is, the greater the deviation of the first edge 5121 from the predetermined position in the first direction X is. the bigger.
  • the value of L5 is set to 80mm-200mm, which can improve the forming effect of the electrode assembly 50 .
  • the first edges 5121 of the two adjacent first stacked segments 512 connected to the bent segment 511 are consistent.
  • the orthographic projections of the first edges 5121 on the same side of the two adjacent first stacking segments 512 coincide, and it can be considered that the first edges of the two adjacent first stacking segments 512 5121 consistent.
  • the first active material layer 51b of one stacking segment 512 can completely cover the second active material layer 52b of the second stacking segment 522, that is, the first edges 5121 of two adjacent first stacking segments 512 can be considered to be the same.
  • This included angle is called the allowable error angle.
  • FIG. 11 is a schematic structural diagram of the first pole piece 51 of the electrode assembly 50 according to another embodiment of the present application in an unfolded state.
  • the bending section 511 includes two openings 514a and a sub-bending section 511a.
  • the sub-bending segment 511a connects two adjacent first laminated segments 512 .
  • the two openings 514a are located on both sides of the sub-bending segment 511a along the first direction X, respectively.
  • the ends of the openings 514a along the first direction X are opened.
  • the bending section 511 may also include only one opening 514a and one sub-bending section 511a, and the opening 514a and the sub-bending section 511a are arranged along the first direction X.
  • FIG. 12 is a schematic diagram of the first pole piece 51 after the opening 514a is formed.
  • the first pole piece 51 includes first laminated sections 512 and bending sections 511 alternately arranged along the length direction H, and each bending section 511 includes four sub-bending sections 511a and three openings 514a.
  • the bent sections 511a and the openings 514a are alternately arranged along the first direction X.
  • the dimension L1 of each opening 514a along the first direction X is 160 mm, and the dimension L2 of each sub-bending segment 511a along the first direction X is 20 mm.
  • the size of the bending section 511 and the first stacking section 512 along the first direction X is 560 mm.
  • the dimension of the first laminated segment 512 in the length direction H of the first pole piece 51 is 88 mm.
  • the dimensions w of the bending section 511 , the sub-bending section 511 a and the opening 514 a in the length direction H are all 0.3 mm.
  • the thickness Da of the first laminated section 512 and the thickness of the bending section 511 are both 0.18 mm.
  • the first laminated segment 512 has two first edges 5121 oppositely arranged along the first direction X and two second edges 5122 oppositely arranged along the length direction H.
  • the opening 514 a is disposed adjacent to the second edge 5122 , and the dotted line in FIG. 12 does not represent a solid structure, but can be schematically used as the second edge 5122 of the first laminated segment 512 .
  • the first edge 5121 and the second edge 5122 are also edges of the first active material layer 51b.
  • Tabs 513 extend from a first edge 5121 .
  • FIG. 13 is a schematic structural diagram of the first pole piece 51 and the isolation film 53 fixed together.
  • the isolation film 53 can be fixed to the first pole piece 51 by means of heat pressing, electrophoresis, or bonding.
  • the separator 53 is a polyethylene film.
  • the thickness Ds of the isolation film 53 is 0.01 mm.
  • FIG. 14 is a schematic view of the strip-shaped electrode assembly 50a, showing the first pole piece 51, the second pole piece 52 and the separator 53 fixed together.
  • the plurality of second pole pieces 52 may be arranged in the manner shown in FIG. 14 .
  • the second pole piece 52 can be fixed to the isolation film 53 by means of heat pressing, electrophoresis, or bonding.
  • FIG. 15 is a partial top plan view of the strip-shaped electrode assembly 50a showing the first pole piece 51 , the second pole piece 52 and the separator 53 fixed together.
  • the second pole piece 52 includes a second laminated segment 522 and a second tab 523 connected to the second laminated segment 522.
  • the second laminated segment 522 includes a third edge 5221 and The fourth edge 5222 from which the second tab 523 extends.
  • the size of the second lamination segment 522 is 558.5 mm.
  • a first edge 5121 of the first lamination segment 512 exceeds the third edge by 1.5 mm, and the first lamination segment 512
  • the other first edge 5121 of is flush with the fourth edge 5222.
  • the size of the portion of the protective coating 52c on the second lamination section 522 along the first direction X is 1.5 mm, that is, in the first direction X, both the first edges 5121 of the first lamination section 512 extend beyond the first direction X.
  • Two active material layers 1.5mm.
  • the dimension of the second lamination section 522 along the length direction H is 86 mm, and the second lamination section 522 has two opposite fifth edges 5223 in the length direction H. As shown in FIG. In the length direction H, the distance between the fifth edge 5223 and the second edge 5122 of the first laminated segment 512 is 1 mm. The thickness Dc of the second laminated section 522 is 0.25 mm. There are 40 second pole pieces 52 .
  • FIG. 16 shows a schematic view of the strip electrode assembly 50a during the folding process.
  • the strip-shaped electrode assembly 50a can be pulled over the forming die 50b, and after entering the cavity of the forming die 50b, the strip-shaped electrode assembly 50a can be folded under the action of gravity.
  • Other auxiliary members may also be used to assist the bending of the strip-shaped electrode assembly 50a.
  • Example 2 An electrode assembly was manufactured according to the same method as Example 1, except that the dimension w of the opening 514a in the length direction H was changed to 0.27 mm.
  • Example 3 An electrode assembly was manufactured according to the same method as Example 1, except that the dimension w of the opening 514a in the length direction H was changed to 0.4 mm.
  • Example 4 An electrode assembly was manufactured according to the same method as Example 1, except that the dimension w of the opening 514a in the length direction H was changed to 0.5 mm.
  • Example 5 An electrode assembly was manufactured according to the same method as Example 1, except that the dimension w of the opening 514a in the length direction H was changed to 0.6 mm.
  • Example 6 An electrode assembly was manufactured according to the same method as Example 1, except that the dimension w of the opening 514a in the length direction H was changed to 0.7 mm.
  • Example 7 An electrode assembly was manufactured according to the same method as Example 1, except that the dimension w of the opening 514a in the length direction H was changed to 0.8 mm.
  • Example 8 An electrode assembly was manufactured according to the same method as Example 1, except that the dimension w of the opening 514a in the length direction H was changed to 0.9 mm.
  • Comparative Example 1 An electrode assembly was manufactured according to the same method as Example 1, except that the dimension w of the opening 514a in the length direction H was changed to 0.1 mm.
  • Comparative Example 2 An electrode assembly was manufactured according to the same method as Example 1, except that the dimension w of the opening 514a in the length direction H was changed to 0.2 mm.
  • Comparative Example 3 An electrode assembly was manufactured according to the same method as Example 1, except that the dimension w of the opening 514a in the length direction H was changed to 1 mm.
  • Comparative Example 4 An electrode assembly was manufactured according to the same method as Example 1, except that the dimension w of the opening 514a in the length direction H was changed to 1.2 mm.
  • Evaluation Example Evaluate the relative position of the edge of the first stack-up segment and the edge of the second stack-up segment.
  • Electrode assemblies according to Examples 1-8 and Comparative Examples 1-4 were fabricated and evaluated.
  • FIG. 17 is a schematic partial cross-sectional view of an electrode assembly according to an embodiment of the present application.
  • the minimum value in the first direction X between the third edge 5221 of each second stacked segment 522 and a first edge 5121 of the corresponding first stacked segment 512 in the first direction X is calculated.
  • D11 is the dimension of one edge of the first active material layer exceeding one edge of the second active material layer in the first direction X.
  • Each second lamination segment 522 is compared with the first lamination segments 512 on both sides thereof, resulting in 80 values.
  • the minimum distance D12a in the first direction X between the fourth edge 5222 of each second stacked segment 522 and the other first edge 5121 of the corresponding first stacked segment 512 is calculated.
  • D12a plus 1.5mm is the dimension D12 that the other edge of the first active material layer exceeds the other edge of the second active material layer in the first direction X.
  • Each second lamination segment 522 is compared with the first lamination segments 512 on both sides thereof, resulting in 80 values.
  • FIG. 18 is another partial cross-sectional schematic diagram of an electrode assembly according to an embodiment of the present application.
  • the minimum distance in the first direction X between the fifth edge 5223 of each second stacking segment 522 and the second edge 5122 of the corresponding first stacking segment 512 is calculated D13.
  • Each second lamination segment 522 is compared with the first lamination segments 512 on either side of it, resulting in 160 values.
  • D11 is a positive value, which means that an edge of the first active material layer exceeds an edge of the second active material layer in the first direction X; D11 is a negative value, which means that an edge of the second active material layer is in One edge beyond the first active material layer in the first direction X.
  • D12 and D13 are positive values, which means that an edge of the first active material layer exceeds an edge of the second active material layer in the first direction X; D11 is a negative value, which means that an edge of the second active material layer is in One edge beyond the first active material layer in the first direction X.
  • Example 1 0.3mm 0.23mm 0.25mm 0.68mm
  • Example 2 0.27mm 0.19mm 0.20mm 0.70mm
  • Example 3 0.4mm 0.37mm 0.35mm 0.61mm
  • Example 4 0.5mm 0.54mm 0.56mm 0.52mm
  • Example 5 0.6mm 0.76mm 0.71mm 0.45mm
  • Example 6 0.7mm 0.56mm 0.53mm 0.34mm
  • Example 7 0.8mm 0.33mm 0.34mm 0.26mm
  • Example 8 0.9mm 0.20mm 0.22mm 0.20mm Comparative Example 1 0.1mm -0.03mm -0.01mm 0.81mm Comparative Example 2 0.2mm 0.09mm 0.07mm 0.74mm Comparative Example 3 1.0mm 0.08mm 0.09mm 0.09mm Comparative Example 4 1.2mm -0.01mm -0.02mm -0.03mm
  • the value of w is within 0.27mm-0.9mm, which satisfies the relation Dc+2Ds ⁇ w ⁇ 2 ⁇ (Dc+2Ds+Da), and the first lamination
  • the first active material layer of the segment can exceed the predetermined size of the second active material layer of the second lamination segment, and the first active material layer of the first lamination segment can completely cover the second active material layer of the second lamination segment, which is lithium ion Provide enough space for lithium intercalation to reduce the phenomenon of lithium precipitation.
  • the value of w is too large or too small, which may prevent the first active material layer of the first stacking section from completely exceeding the second active material layer of the second stacking section, or the first stacking section
  • the size of the first active material layer beyond the second active material layer of the second lamination section is too small; compared with Examples 1-8, the electrode assembly in Comparative Examples 1-4 has a higher risk of lithium evolution. Therefore, compared with the electrode assemblies in Comparative Examples 1-4, the electrode assemblies in Examples 1-8 have better electrochemical performance and higher safety.
  • FIG. 19 is a schematic flowchart of a method for manufacturing an electrode assembly according to an embodiment of the present application. As shown in Figure 19, the manufacturing method includes:
  • the first pole piece includes a plurality of bending segments and a plurality of first stacking segments, each bending segment is used to connect two adjacent first stacking segments, and the bending segment has a guide portion , the guide part is used to guide the bending of the bending section during production;
  • S830 provide a plurality of second pole pieces, the second pole pieces are opposite in polarity to the first pole pieces and include a second lamination segment, and the second pole pieces are fixed on the surface of the isolation film that is away from the first pole piece;
  • S840 bends the bending segment under the guidance of the guiding part, so that a plurality of first lamination segments are arranged in layers, the second lamination segment of each second pole piece is arranged between two adjacent first lamination segments, and each Each isolation segment is disposed between the adjacent first stack segment and the second stack segment.
  • the thickness of the first stacking segment is Da
  • the thickness of the second stacking segment is Dc
  • the thickness of the isolation segment is Ds
  • the thickness of the guide portion in the bending direction of the bending segment is Ds.
  • the dimension is w, and w, Da, Dc and Ds satisfy the relation: Dc+2Ds ⁇ w ⁇ 2 ⁇ (Dc+2Ds+Da).
  • FIG. 20 is a schematic block diagram of a system for manufacturing a battery cell according to an embodiment of the present application.
  • the manufacturing system 900 includes a first providing device 910 , a second providing device 920 , a first assembling device 930 , a third providing device 940 , a second assembling device 950 and a third assembling device 960 .
  • the first providing device 910 is used to provide a first pole piece, the first pole piece includes a plurality of bending segments and a plurality of first stacking segments, each bending segment is used to connect two adjacent first stacking segments,
  • the bending section has guides for guiding the bending of the bending section during production.
  • the second providing device 920 is used to provide an isolation membrane, and the isolation membrane includes a plurality of isolation segments.
  • the first assembling device 930 is used to fix the isolation diaphragm on the two surfaces of the first pole piece.
  • the third providing means 940 is used for providing a plurality of second pole pieces, the second pole pieces are opposite in polarity to the first pole pieces and include second lamination segments.
  • the second assembling device 950 is used to fix the second pole piece to the surface of the isolation membrane facing away from the first pole piece.
  • the third assembling device 960 is used to bend the bending segment under the guidance of the guide part, so that a plurality of first lamination segments are arranged in layers, and the second lamination segment of each second pole piece is arranged in two adjacent first lamination segments.
  • each isolation segment is disposed between adjacent first lamination segments and second lamination segments.
  • the thickness of the first stacking segment is Da
  • the thickness of the second stacking segment is Dc
  • the thickness of the isolation segment is Ds
  • the thickness of the guide portion in the bending direction of the bending segment is Ds.
  • the dimension is w, and w, Da, Dc and Ds satisfy the relation: Dc+2Ds ⁇ w ⁇ 2 ⁇ (Dc+2Ds+Da).

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Abstract

一种电极组件（50）及其制造方法和制造系统、电池单体（40）、电池（10）及用电装置。电极组件（50）包括：第一极片（51），包括多个折弯段（511）和多个层叠设置的第一层叠段（512），每个折弯段（511）用于连接两个相邻的第一层叠段（512），折弯段（511）具有引导部（514），引导部（514）用于在生产时引导折弯段（511）折弯；多个第二极片（52），第二极片（52）与第一极片（51）极性相反且包括第二层叠段（522），每个第二极片（52）的第二层叠段（522）设置于相邻两个第一层叠段（512）之间；隔离膜（53），用于将第一极片（51）和第二极片（52）隔开，隔离膜（53）包括多个隔离段（531），每个隔离段（531）设置于相邻的第一层叠段（512）和第二层叠段（522）之间。引导部（514）能够引导第一极片（51）在预定区域折弯，降低第一极片（51）和第二极片（52）偏离预定位置的风险，减少析锂。

Description

电极组件及其制造方法和制造系统、电池单体、电池及用电装置 技术领域
本申请涉及电池技术领域，并且更具体地，涉及一种电极组件及其制造方法和制造系统、电池单体、电池及用电装置。
背景技术
可再充电电池，可以称为二次电池，是指在电池放电后可通过充电的方式使活性物质激活而继续使用的电池。可再充电电池广泛用于电子设备，例如手机、笔记本电脑、电瓶车、电动汽车、电动飞机、电动轮船、电动玩具汽车、电动玩具轮船、电动玩具飞机和电动工具等等。
在电池技术的发展中，除了提高电池的性能外，安全问题也是一个不可忽视的问题。如果电池的安全问题不能保证，那该电池就无法使用。因此，如何增强电池的安全性，是电池技术中一个亟待解决的技术问题。
发明内容
本申请提供了一种电极组件及其制造方法和制造系统、电池单体、电池及用电装置，能够降低析锂风险，增强电池的安全性。
第一方面，本申请实施例提供了一种电极组件，其包括：第一极片，包括多个折弯段和多个层叠设置的第一层叠段，每个折弯段用于连接两个相邻的第一层叠段，折弯段具有引导部，引导部用于在生产时引导折弯段折弯；多个第二极片，第二极片与第一极片极性相反且包括第二层叠段，每个第二极片的第二层叠段设置于相邻两个第一层叠段之间；隔离膜，用于将第一极片和第二极片隔开，隔离膜包括多个隔离段，每个隔离段设置于相邻的第一层叠段和第二层叠段之间。其中，在多个第一层叠段的层叠方向上，第一层叠段的厚度为Da，第二层叠段的厚度为Dc，隔离段的厚度为Ds；引导部在折弯段的弯折方向的尺寸为w，w、Da、Dc及Ds满足关系式：Dc+2Ds≤w≤2×(Dc+2Ds+Da)。
在本申请实施例中，当引导部的尺寸w满足关系式Dc+2Ds≤w≤2×(Dc+2Ds+Da)时，引导部能够引导第一极片在预定区域折弯，提高折弯位置的可控性和准确性，降低第一极片和第二极片偏离预定位置的风险，减少析锂；同时，引导部还能够减小折弯段上的第一活性物质层的应力集中，为第二层叠段和隔离膜提供足够空间，减小折弯段对第二层叠段和隔离膜施加的挤压力，减少掉粉。
在一些实施例中，引导部沿第一方向设置，第一方向与折弯段的弯折方向垂直。
在一些实施例中，引导部包括至少一个开孔。开孔能够减小折弯段的强度，使折弯段更易折弯。通过设置开孔，去除折弯段的至少部分的第一活性物质层，以减小折弯段上的第一活性物质层的应力集中，为第二层叠段和隔离膜提供空间，减小折弯段对第二层叠段和隔离膜施加的挤压力，减少掉粉。
在一些实施例中，开孔贯通折弯段。开孔可以通过冲切第一极片形成，成型工艺简单。贯通的开孔还可以减小电极组件的重量，提高电极组件的能量密度。电解液还可以穿过开孔并浸润第二极片，从而提高电极组件的浸润性。
在一些实施例中，折弯段包括多个子折弯段，子折弯段和开孔沿第一方向交替设置。通过增加子折弯段数量，可以减小子折弯段沿第一方向的尺寸，使各子折弯段更容易折弯，有助于引导第一极片的折叠。
在一些实施例中，开孔沿第一方向的尺寸为L1，子折弯段沿第一方向的尺寸为L2，2≤L1/L2≤40。这样能够在避免子折弯段断裂的前提下，提高子折弯段的折弯效果。
在一些实施例中，引导部包括多个开孔，多个开孔间隔设置。
在一些实施例中，多个开孔沿第一方向间隔设置。增加开孔的数量，可以对应地增加子折弯段数量，减小子折弯段沿第一方向的尺寸，使各子折弯段更容易折弯，有助于引导第一极片的折叠。
在一些实施例中，开孔为圆形、椭圆形、跑道形或多边形。可选地，多边形的角部为圆角。圆角可以多边形开孔的角部更为平滑，在开孔成型时可以减小第一极片上的毛刺。
在一些实施例中，引导部沿第一方向的尺寸为L3，折弯段沿第一方向的尺寸为L4，0.5≤L3/L4≤0.99。这样能够在降低折弯段断裂风险的前提下，提高折弯段的折弯效果和引导部的引导效果。
在一些实施例中，折弯段沿第一方向的尺寸L4为200mm-1200mm。当折弯段的尺寸L4为200mm-1200mm时，折弯段的折弯效果更好。
在一些实施例中，多个折弯段包括第一折弯段和第二折弯段，第一折弯段和第二折弯段分别连接于第一层叠段沿第二方向的两端，第一折弯段上的引导部和第二折弯段上的引导部沿第二方向的间距L5为80mm-200mm，第二方向垂直于第一方向和层叠方向。将L5的值设置为80mm-200mm，可以改善电极组件的成型效果。
在一些实施例中，第一极片为负极极片，第二极片为正极极片。折弯段的第一活性物质层可以为锂离子提供嵌锂空间，降低析锂风险。
在一些实施例中，第一极片包括第一集流体和设置于第一集流体表面的第一活性物质层，第二极片包括第二集流体和设置于第二集流体表面的第二活性物质层。在层叠方向上，第一层叠段的第一活性物质层完全覆盖第二层叠段的第二活性物质层。第一层叠段的第一活性物质层能够为第二活性物质层脱嵌出的锂离子提供嵌锂空间，减少析锂。
在一些实施例中，在垂直于层叠方向的方向上，第一层叠段的第一活性物质层至少超出第二层叠段的第二活性物质层0.1mm。第一层叠段的第一活性物质层能够为第 二活性物质层脱嵌出的锂离子提供足够的嵌锂空间，降低析锂的风险。
在一些实施例中，每个第一层叠段具有相对的两个第一边缘，在生产时引导折弯段折弯后，与折弯段相连接的两个相邻第一层叠段的第一边缘一致。
第二方面，本申请实施例提供了一种电池单体，包括：壳体，具有容纳腔和开口；至少一个第一方面的电极组件，容纳于容纳腔中；盖板，用于封闭壳体的开口。
第三方面，本申请实施例提供了一种电池，包括：箱体；至少一个第二方面的电池单体，电池单体收容于箱体内。
第四方面，本申请实施例提供了一种用电装置，用电装置被配置为接收从第三方面的电池提供的电力。
第五方面，本申请实施例提供了一种电极组件的制造方法，其包括：提供第一极片，第一极片包括多个折弯段和多个第一层叠段，每个折弯段用于连接两个相邻的第一层叠段，折弯段具有引导部，引导部用于在生产时引导折弯段折弯；提供隔离膜，并将隔离膜固定于第一极片的两个表面，隔离膜包括多个隔离段；提供多个第二极片，第二极片与第一极片极性相反且包括第二层叠段，并将第二极片固定于隔离膜的背离第一极片的表面；在引导部的引导下将折弯段折弯，以使多个第一层叠段层叠设置、每个第二极片的第二层叠段设置于相邻两个第一层叠段之间、每个隔离段设置于相邻的第一层叠段和第二层叠段之间。其中，在多个第一层叠段的层叠方向上，第一层叠段的厚度为Da，第二层叠段的厚度为Dc，隔离段的厚度为Ds，引导部在折弯段的弯折方向的尺寸为w，w、Da、Dc及Ds满足关系式：Dc+2Ds≤w≤2×(Dc+2Ds+Da)。
第六方面，本申请实施例提供了一种电极组件的制造系统，包括：第一提供装置，用于提供第一极片，第一极片包括多个折弯段和多个第一层叠段，每个折弯段用于连接两个相邻的第一层叠段，折弯段具有引导部，引导部用于在生产时引导折弯段折弯；第二提供装置，用于提供隔离膜，隔离膜包括多个隔离段；第一组装装置，用于将隔离膜固定于第一极片的两个表面；第三提供装置，用于提供多个第二极片，第二极片与第一极片极性相反且包括第二层叠段；第二组装装置，用于将第二极片固定于隔离膜的背离第一极片的表面；第三组装装置，用于在引导部的引导下将折弯段折弯，以使多个第一层叠段层叠设置、每个第二极片的第二层叠段设置于相邻两个第一层叠段之间、每个隔离段设置于相邻的第一层叠段和第二层叠段之间；其中，在多个第一层叠段的层叠方向上，第一层叠段的厚度为Da，第二层叠段的厚度为Dc，隔离段的厚度为Ds，引导部在折弯段的弯折方向的尺寸为w，w、Da、Dc及Ds满足关系式：Dc+2Ds≤w≤2×(Dc+2Ds+Da)。
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为本申请一个实施例的车辆的结构示意图；
图2为本申请一个实施例的电池的结构示意图；
图3为本申请一个实施例的电池模块的结构示意图；
图4为本申请一个实施例的电池单体的结构示意图；
图5为本申请一个实施例的电极组件的前视示意图；
图6为图5所示的电极组件沿线A-A作出的剖视示意图；
图7为图5所示的电极组件沿线B-B作出的剖视示意图；
图8为图6所示的电极组件在方框C处的放大示意图；
图9为本申请一个实施例的电极组件的第一极片在折叠状态下的结构示意图；
图10为本申请一个实施例的电极组件的第一极片在展开状态下的结构示意图；
图11为本申请另一个实施例的电极组件的第一极片在展开状态下的结构示意图；
图12至图16为本申请的一个实施例的电极组件在成型过程中的示意图；
图17为本申请一个实施例的电极组件的一局部剖视示意图；
图18为本申请一个实施例的电极组件的一局部剖视示意图；
图19为本申请一个实施例的一种电极组件的制造方法的示意性流程图；
图20为本申请一个实施例的一种电池单体的制造系统的示意性框图。
在附图中，附图并未按照实际的比例绘制。
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。本领域技术人员显式地和隐式地理解的是，本申请所描述的实施例可以与其它实施例相结合。
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。
本申请中出现的“多个”指的是两个以上(包括两个)，同理，“多组”指的是两组以上(包括两组)，“多片”指的是两片以上(包括两片)。
本申请中术语“平行”不仅包括绝对平行的情况，也包括了工程上常规认知的大致平行的情况；同时，“垂直”也不仅包括绝对垂直的情况，还包括工程上常规认知的大致垂直的情况。
本申请中，电池单体可以包括锂离子二次电池、锂离子一次电池、锂硫电池、钠锂离子电池、钠离子电池或镁离子电池等，本申请实施例对此并不限定。电池单体可呈圆柱体、扁平体、长方体或其它形状等，本申请实施例对此也不限定。电池单体一般按封装的方式分成三种：柱形电池单体、方体方形电池单体和软包电池单体，本申请实施例对此也不限定。
本申请的实施例所提到的电池是指包括一个或多个电池单体以提供更高的电压和容量的单一的物理模块。例如，本申请中所提到的电池可以包括电池模块或电池包等。电池一般包括用于封装一个或多个电池单体的箱体。箱体可以避免液体或其他异物影响电池单体的充电或放电。
电池单体包括电极组件和电解液，电极组件由正极极片、负极极片和隔离膜组成。电池单体主要依靠金属离子在正极极片和负极极片之间移动来工作。正极极片包括正极集流体和正极活性物质层，正极活性物质层涂覆于正极集流体的表面，未涂敷正极活性物质层的集流体凸出于已涂覆正极活性物质层的集流体，未涂敷正极活性物质层的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。负极极片包括负极集流体和负极活性物质层，负极活性物质层涂覆于负极集流体的表面，未涂敷负极活性物质层的集流体凸出于已涂覆负极活性物质层的集流体，未涂敷负极活性物质层的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。隔离膜具有大量贯通的微孔，能够保证电解质离子自由通过，对锂离子有很好的穿透性。隔离膜的材质可以为PP或PE等。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。
锂离子电池在充电时，锂离子从正极极片脱嵌并嵌入负极极片，但是可能会发生一些异常情况，例如，负极嵌锂空间不足、锂离子嵌入负极阻力太大或锂离子过快的从正极脱嵌，脱嵌的锂离子无法等量的嵌入负极极片的负极活性物质层，无法嵌入负极极片的锂离子只能在负极表面得电子，从而形成银白色的金属锂单质，这就是析 锂现象。析锂不仅使锂离子电池性能下降，循环寿命大幅缩短，还限制了锂离子电池的快充容量。除此之外，锂离子电池发生析锂时，析出来的锂金属非常活泼，在较低的温度下便可以与电解液发生反应，造成电池自产热起始温度(Tonset)降低和自产热速率增大，严重危害电池的安全。再者，析锂严重时，脱嵌的锂离子可以在负极极片表面形成锂结晶，而锂结晶容易刺破隔离膜，造成相邻的正极极片和负极极片具有短路的风险。
发明人在注意到现有电池单体存在电化学性能较差的问题之后，发现是由于成型的电极组件中的正极极片和负极极片中的至少一者偏离预定位置，因此影响了电极组件的电化学性能。发明人进一步发现成型的电极组件中的正极极片和负极极片中的至少一者偏离预定位置，导致电极组件存在析锂现象，从而影响了二次电池存在电化学性能。由此推测原因可能是负极活性物质层无法完全覆盖正极活性物质层，导致脱嵌的锂离子无法等量的嵌入负极极片的负极活性物质层。
鉴于此，本申请欲提供了一种电极组件，其能够使正极极片和负极极片处于预定位置，降低析锂风险，保证电极组件具有良好的电化学性能，提高电池的安全性。
本申请实施例描述的技术方案均适用于各种使用电池的装置，例如，手机、便携式设备、笔记本电脑、电瓶车、电动玩具、电动工具、电动车辆、船舶和航天器等，例如，航天器包括飞机、火箭、航天飞机和宇宙飞船等。
应理解，本申请实施例描述的技术方案不仅仅局限适用于上述所描述的设备，还可以适用于所有使用电池的设备，但为描述简洁，下述实施例均以电动车辆为例进行说明。
例如，如图1所示，为本申请一个实施例的一种车辆1的结构示意图，车辆1可以为燃油汽车、燃气汽车或新能源汽车，新能源汽车可以是纯电动汽车、混合动力汽车或增程式汽车等。车辆1的内部可以设置电池10、控制器20以及马达30，控制器20用来控制电池10为马达30的供电。例如，在车辆1的底部或车头或车尾可以设置电池10。电池10可以用于车辆1的供电，例如，电池10可以作为车辆1的操作电源，用于车辆1的电路系统，例如，用于车辆1的启动、导航和运行时的工作用电需求。在本申请的另一实施例中，电池10不仅仅可以作为车辆1的操作电源，还可以作为车辆1的驱动电源，替代或部分地替代燃油或天然气为车辆1提供驱动动力。
为了满足不同的使用电力需求，电池10可以包括多个电池单体，其中，多个电池单体之间可以串联或并联或混联，混联是指串联和并联的混合。电池10也可以称为电池包。可选地，多个电池单体可以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组成电池10。也就是说，多个电池单体可以直接组成电池10，也可以先组成电池模块，电池模块再组成电池10。
例如，如图2所示，为本申请一个实施例的一种电池10的结构示意图，电池10可以包括多个电池单体40。电池10还可以包括箱体(或称罩体)，箱体内部为中空结构，多个电池单体40容纳于箱体内。如图2所示，箱体可以包括两部分，这里分别称为第一部分111和第二部分112，第一部分111和第二部分112扣合在一起。第一部分111和第二部分112的形状可以根据多个电池单体40组合的形状而定，第一部分111 和第二部分112可以均具有一个开口。例如，第一部分111和第二部分112均可以为中空长方体且各自只有一个面为开口面，第一部分111的开口和第二部分112的开口相对设置，并且第一部分111和第二部分112相互扣合形成具有封闭腔室的箱体。多个电池单体40相互并联或串联或混联组合后置于第一部分111和第二部分112扣合后形成的箱体内。
可选地，电池10还可以包括其他结构，在此不再一一赘述。例如，该电池10还可以包括汇流部件，汇流部件用于实现多个电池单体40之间的电连接，例如并联或串联或混联。具体地，汇流部件可通过连接电池单体40的电极端子实现电池单体40之间的电连接。进一步地，汇流部件可通过焊接固定于电池单体40的电极端子。多个电池单体40的电能可进一步通过导电机构穿过箱体而引出。可选地，导电机构也可属于汇流部件。
根据不同的电力需求，电池单体40的数量可以设置为任意数值。多个电池单体40可通过串联、并联或混联的方式连接以实现较大的容量或功率。由于每个电池10中包括的电池单体40的数量可能较多，为了便于安装，可以将电池单体40分组设置，每组电池单体40组成电池模块。电池模块中包括的电池单体40的数量不限，可以根据需求设置。例如，图3为电池模块的一个示例。电池10可以包括多个电池模块，这些电池模块可通过串联、并联或混联的方式进行连接。
如图4所示，为本申请一个实施例的一种电池单体40的结构示意图。申请实施例的电池单体40包括电极组件50、壳体60和端盖组件70，壳体60具有容纳腔和开口，电极组件50容纳于容纳腔中。壳体60根据一个或多个电极组件50组合后的形状而定例如，壳体60可以为中空的长方体或正方体或圆柱体，且壳体60的其中一个面具有开口以便一个或多个电极组件50可以放置于壳体60内。例如，当壳体60为中空的长方体或正方体时，壳体60的其中一个平面为开口面，即该平面不具有壁体而使得壳体60内外相通。端盖组件70包括盖板71，盖板71覆盖开口并且与壳体60连接，进而封闭壳体60的开口，使电极组件50放置在封闭的腔体内。壳体60内填充有电解质，例如电解液。
该端盖组件70还可以包括两个电极端子72，两个电极端子72可以设置在盖板71上。盖板71通常是平板形状，两个电极端子72固定在盖板71的平板面上，两个电极端子72分别为正电极端子和负电极端子。每个电极端子72各对应设置一个连接构件73，或者也可以称为集流构件，其用于将电极组件50和电极端子72实现电连接。
每个电极组件50具有第一极耳513和第二极耳523。第一极耳513和第二极耳523的极性相反。例如，当第一极耳513为正极极耳时，第二极耳523为负极极耳。一个或多个电极组件50的第一极耳513通过一个连接构件73与一个电极端子72连接，一个或多个电极组件50的第二极耳523通过另一个连接构件73与另一个电极端子72连接。例如，正电极端子通过一个连接构件73与正极极耳连接，负电极端子通过另一个连接构件73与负极极耳连接。
在该电池单体40中，根据实际使用需求，电极组件50可设置为单个或多个。
如图5所示，为本申请一个实施例的电极组件50的前视示意图；图6为图5所 示的电极组件50沿线A-A作出的剖视示意图；图7为图5所示的电极组件50沿线B-B作出的剖视示意图；图8为图6所示的电极组件50在方框C处的放大示意图。
如图5至图8所示，本申请实施例的电极组件50包括第一极片51、第二极片52和隔离膜53，隔离膜53用于将第一极片51和第二极片52隔开。第二极片52与第一极片51极性相反，例如，当第一极片51为负极极片时，第二极片52为正极极片，当第一极片51为正极极片时，第二极片52为负极极片。
第一极片51包括第一集流体51a和设置于第一集流体51a表面的第一活性物质层51b。第一集流体51a包括第一涂覆区和第一凸出区，第一涂覆区涂覆有第一活性物质层51b，第一凸出区凸出于第一涂覆区，且第一凸出区至少部分未涂覆第一活性物质层51b。第一凸出区的未涂覆第一活性物质层51b的部分用于连接到连接构件73，即第一凸出区作为第一极耳513。
第二极片52包括第二集流体52a和设置于第二集流体52a表面的第二活性物质层52b。第二集流体52a包括第二涂覆区和第二凸出区，第二涂覆区涂覆有第二活性物质层52b，第二凸出区凸出于第二涂覆区，且第二凸出区至少部分未涂覆第二活性物质层52b。第二凸出区的未涂覆第二活性物质层52b的部分用于连接到连接构件73，即第二凸出区作为第二极耳523。
第一极耳513和第二极耳523通常通过裁切工艺形成。在一些实施例中，第二极片52还包括保护涂层52c，保护涂层52c涂覆于第二集流体52a的表面且连接第二活性物质层52b，保护涂层52c位于第二活性物质层52b的靠近第二凸出区的一侧。保护涂层52c的一部分涂覆于第二涂覆区，保护涂层52c的另一部分涂覆于第二凸出区。第二凸出区的未被保护涂层52c覆盖的区域用于连接到连接构件73。保护涂层52c能够在第二极耳523的裁切工艺中减小裁切处的毛刺。
第一极片51包括多个折弯段511和多个层叠设置的第一层叠段512，每个折弯段511用于连接两个相邻的第一层叠段512。在本实施例中，第一极片51整体为连续延伸结构，且大体呈Z字形往复折弯。多个第一层叠段512沿层叠方向Z依次层叠。
在电极组件50中，折弯段511至少部分处于折弯状态。在一些示例中，折弯段511整体处于折弯状态，且折弯段511大体呈弧形，例如可以是圆弧形。在另一些示例中，折弯段511仅部分处于折弯状态；具体地，折弯段511具有弧形区5111和平直区5112，弧形区5111整体折弯为弧形，例如可以是圆弧形，平直区5112呈平板状并连接弧形区5111和第一层叠段512。
在一些实施例中，第一层叠段512整体为平板状且垂直于层叠方向Z。在另一些实施例中，第一层叠段512的连接于折弯段511的端部也可以处于折弯状态。
第二极片52设置于为多个。每个第二极片52包括第二层叠段522，每个第二极片52的第二层叠段522设置于相邻两个第一层叠段512之间。多个第二极片52彼此分离。第二层叠段522大体为平板状且垂直于层叠方向Z，层叠方向Z平行于第一层叠段512的厚度方向和第二层叠段522的厚度方向。
隔离膜53包括多个隔离段531，每个隔离段531设置于相邻的第一层叠段512和第二层叠段522之间。隔离段531能够将相邻的第一层叠段512和第二层叠段522绝 缘隔开，以降低短路风险。隔离段531平行于第一层叠段512和第二层叠段522，隔离段531的厚度方向平行于层叠方向Z。在一些实施例中，隔离膜53还包括设置于各折弯段511的内外两侧的连接段532，且连接段532用于连接两个隔离段531。连接段532能够将折弯段511和第二层叠段522绝缘隔开，降低短路风险。可选地，隔离膜53为两个，各隔离膜53呈Z字形往复折弯以形成隔离段531和连接段532。
第一极耳513从第一层叠段512的边缘延伸，第二极耳523从第二层叠段522的边缘延伸。在一些示例中，第一极耳513的数量和第一层叠段512的数量相同，且第一极耳513和第一层叠段512一一对应设置。第二极耳523的数量和第二层叠段522的数量相同，且第二极耳523和第二层叠段522一一对应设置。
通过对电极组件的成型过程进行分析，发明人对析锂现象进一步研究发现，第一极片整体为连续结构，在折弯过程中很难能沿预定区域进行折弯，导致第一极片和第二极片在堆叠形成电极组件后，存在负极活性物质层无法完全覆盖正极活性物质层的情况，容易导致电极组件存在析锂现象，从而影响二次电池的电化学性能和安全性能。另外，第一极片折弯时，折弯段上的第一活性物质层会产生应力集中，导致活性物质脱落，称之为掉粉现象。折弯段和第二层叠段之间的空间有限，因此可能会存在折弯段挤压第二层叠段边缘的情况，这种情况也会造成第二层叠段上的第二活性物质层脱落；同时，折弯段还可能挤压隔离膜，导致折弯段和第二层叠段之间的隔离膜褶皱。
基于发明人发现的上述问题，发明人对第一极片的结构进行改进。
具体地，在一些实施例中，折弯段511具有引导部514，引导部514用于在生产时引导折弯段511折弯。在电极组件50的生产过程中，对第一极片51施加外力以折弯第一极片51时，引导部514能够引导第一极片51在预定区域进行折弯以形成折弯段511，从而有利于提高折弯位置的可控性和准确性，进而降低第一极片51和第二极片52偏离预定位置的风险，降低第一层叠段512和第二层叠段522中的负极活性物质层无法完全覆盖正极活性物质层的可能性，减少析锂，改善电极组件50的电化学性能。
在一些实施例中，引导部514的数量可以与折弯段511的数量相同，且引导部514和折弯段511一一对应设置。当然，在另一些实施例中，所有折弯段511中部分数量的折弯段511设置有引导部514，而其它的折弯段511可以不设置引导部514。
引导部514可以为事物留下的痕迹。可选地，引导部514可以是指通过材料去除部件在第一极片51上去除部分的第一活性物质层51b形成的结构，或者，引导部514可以是指通过材料去除部件在第一极片51上去除部分的第一活性物质层51b和部分第一集流体51a后形成的结构。通过开设引导部514，可以减小折弯段511的强度，以使折弯段511更容易折弯。第一活性物质层51b自身具有一定的脆性，在折弯的过程中存在因应力集中而出现掉粉的可能性。通过在折弯段511上开设引导部514，可以去除折弯段511上的部分第一活性物质层51b，减小折弯段511上的第一活性物质层51b的应力集中；同时，通过在折弯段511上开设引导部514，还可以给第二层叠段522和隔离膜53提供空间，减小折弯段511对第二层叠段522和隔离膜53施加的挤压力，减少掉粉。
折弯段511在相邻的两个第一层叠段512之间延伸。折弯段511平行于第一方向X，第一方向X垂直于层叠方向Z。具体地，折弯段511沿着图示的弯折方向S延伸，该弯折方向S可以理解为平行于折弯段511的表面的方向。弯折方向S垂直于第一方向X。
引导部514有利于提高折弯位置的可控性和准确性，进而降低第一极片51和第二极片52偏离预定位置的风险。发明人进一步发现，引导部514沿弯折方向S的尺寸对第一极片51的折弯位置有直接的影响。
具体地，如果引导部514沿弯折方向S尺寸过小，那么在第一极片51折弯堆叠的过程中，引导部514的引导作用有限，这样会增大第一极片51未在预定区域折弯的可能性，造成第一层叠段512偏离预定位置的风险。另外，引导部514减小折弯段511的第一活性物质层51b的应力集中的作用不明显，折弯段511仍然存在掉粉风险。引导部514为第二层叠段522和隔离膜53提供的空间偏小，折弯段511对第二层叠段522和隔离膜53施加的挤压力偏大，第二层叠段522仍然存在掉粉风险。
如果引导部514沿弯折方向S尺寸过大，那么第一极片51的容易折弯的区域过大，这样也会增大第一极片51未在预定区域折弯的概率，造成第一层叠段512偏离预定位置的风险，导致电极组件50变形严重。同时，如果引导部514沿弯折方向S尺寸过大，那么引导部514可能会延伸到第二极片52沿层叠方向Z的一侧，此时，引导部514无法为第一极片51脱嵌出的锂离子提供嵌锂空间，引发析锂的风险。
鉴于此，发明人对第一极片51的结构进行进一步地改进。具体地，在层叠方向Z上，第一层叠段512的厚度为Da，第二层叠段522的厚度为Dc，隔离段531的厚度为Ds；引导部514在弯折方向S的尺寸为w。其中，w、Da、Dc及Ds满足关系式：Dc+2Ds≤w≤2×(Dc+2Ds+Da)。可选地，Da的值为0.11mm-0.25mm，Dc的值为0.16mm-0.3mm，Ds的值为0.009mm-0.02mm。
发明人通过研究和试验，发现当引导部514的尺寸w满足上述关系式时，引导部514能够引导第一极片51在预定区域折弯，提高折弯位置的可控性和准确性，降低第一极片51和第二极片52偏离预定位置的风险，减少析锂；同时，引导部514还能够减小折弯段511上的第一活性物质层51b的应力集中，为第二层叠段522和隔离膜53提供足够空间，减小折弯段511对第二层叠段522和隔离膜53施加的挤压力，减少掉粉。
在弯折方向S上，折弯段511的尺寸与引导部514的尺寸w相关联。具体地，在一些示例中，在弯折方向S上，引导部514的尺寸w等于折弯段511的尺寸。也就是说，可以根据引导部514在弯折方向S上的边缘来界定折弯段511和第一层叠段512。
在一些实施例中，第一极片51为负极极片，第二极片52为正极极片。折弯段511的第一活性物质层51b可以为锂离子提供嵌锂空间，降低析锂风险。
在一些实施例中，在层叠方向Z上，第一层叠段512的第一活性物质层51b完全覆盖第二层叠段522的第二活性物质层52b。在此处，“完全覆盖”指的是在垂直于层叠方向Z的平面内，第二层叠段522的第二活性物质层52b的正投影完全位于第一层叠段512的第一活性物质层51b的正投影内，此时，第二层叠段522的第二活性物质层 52b的投影面积小于第一层叠段512的第一活性物质层51b的投影面积。
第一层叠段512的第一活性物质层51b能够为第二活性物质层52b脱嵌出的锂离子提供嵌锂空间，减少析锂。
在一些实施例中，在垂直于层叠方向Z的方向上，第一层叠段512的第一活性物质层51b至少超出第二层叠段522的第二活性物质层0.1mm。具体地，在第一方向X上，第一层叠段512的第一活性物质层51b至少超出第二层叠段522的第二活性物质层0.1mm；在第二方向Y上，第一层叠段512的第一活性物质层51b至少超出第二层叠段522的第二活性物质层0.1mm。第二方向Y垂直于第一方向X和层叠方向Z。此时，第一层叠段512的第一活性物质层51b能够为第二活性物质层52b脱嵌出的锂离子提供足够的嵌锂空间，减少析锂。
图9为本申请一个实施例的电极组件50的第一极片51在折叠状态下的结构示意图；图10为本申请一个实施例的电极组件50的第一极片51在展开状态下的结构示意图。其中，图10中的虚线并不表示实体结构，而是示意性的显示折弯段511和第一层叠段512的分割线。
第一极片51在展开状态下，第一极片51沿自身的长度方向H延伸，第一层叠段512和折弯段511沿长度方向H交替设置。每个折弯段511连接相邻的两个第一层叠段512。第一极片51在折叠状态下，引导部514沿弯折方向S的尺寸w即为：第一极片51在展开状态下，引导部514沿长度方向H的尺寸。第一极片51在展开状态下，第一方向X平行于第一极片51自身的宽度方向。
在一些实施例中，引导部514包括至少一个开孔514a。通过去除折弯段511的一部分材料，以在折弯段511上形成开孔514a。开孔514a能够减小折弯段511的强度，使折弯段511更易折弯。通过设置开孔514a，去除折弯段511的至少部分的第一活性物质层，以减小折弯段511上的第一活性物质层的应力集中，为第二层叠段和隔离膜提供空间，减小折弯段511对第二层叠段和隔离膜施加的挤压力，减少掉粉。
在一些实施例中，开孔514a可以为盲孔；换句话说，开孔514a为未贯通折弯段511的凹槽。在一些示例中，开孔514a相对于折弯段511的面向第二层叠段的表面凹陷设置。可选地，开孔514a通过去除部分的第一活性物质层形成，且开孔514a延伸到第一集流体并将第一集流体露出。
在一些实施例中，开孔514a为通孔并贯通折弯段511。开孔514a贯穿折弯段511的第一集流体以及第一集流体两侧的第一活性物质层。开孔514a可以通过冲切第一极片51形成，成型工艺简单。贯通的开孔514a可以减小折弯段511上的第一活性物质层的应力集中，为第二层叠段和隔离膜提供足够空间，减小折弯段511对第二层叠段和隔离膜施加的挤压力，减少掉粉。贯通的开孔514a还可以减小电极组件的重量，提高电极组件的能量密度。电解液还可以穿过开孔514a并浸润第二极片，从而提高电极组件的浸润性。
在一些实施例中，折弯段511包括多个子折弯段511a，子折弯段511a和开孔514a沿第一方向X交替设置。各子折弯段511a将相邻的两个第一层叠段512连接。通过增加子折弯段511a数量，可以减小子折弯段511a沿第一方向X的尺寸，使各子折弯 段511a更容易折弯，有助于引导第一极片51的折叠。
当开孔514a为通孔时，多个子折弯段511a彼此分离。当开孔514a为盲孔时，折弯段511还包括子连接段，子连接段为开孔514a的底壁，子连接段连接相邻的两个子折弯段511a。
在一些实施例中，开孔514a沿第一方向X的尺寸为L1，子折弯段511a沿第一方向X的尺寸为L2。第一极片51沿第一方向X的尺寸一定，L1的值越大，L2的值也就越小，子折弯段511a也就更容易折弯，对应地，子折弯段511a的强度越低、越容易在折弯的过程中断裂；反之，L1的值越小，L2的值也就越大，子折弯段511a也就越难折弯，子折弯段511a的引导效果越差。发明人综合考虑子折弯段511a的折弯效果和强度，经过研究和试验后，发现当2≤L1/L2≤40时，能够在避免子折弯段511a断裂的前提下，提高子折弯段511a的折弯效果。可选地，L1/L2的值为10、20和30。
在一些实施例中，引导部514包括多个开孔514a，多个开孔514a间隔设置。可选地，多个开孔514a沿第一方向X间隔设置。增加开孔514a的数量，可以对应地增加子折弯段511a数量，减小子折弯段511a沿第一方向X的尺寸，使各子折弯段511a更容易折弯，有助于引导第一极片51的折叠。
在一些实施例中，开孔514a为圆形、椭圆形、跑道形或多边形。在此说明的是，上述的形状指的是在第一极片51处于展开状态时的开孔514a形状。在一些示例中，多边形的开孔514a的角部为圆角；圆角可以多边形开孔514a的角部更为平滑，在开孔514a成型时可以减小第一极片51上的毛刺。例如，开孔514a大体为矩形且四个角部为圆角。在第一极片51处于展开状态时，开孔514a沿第一方向X的尺寸大于开孔514a沿长度方向H的尺寸。
引导部514沿第一方向X的尺寸为L3。具体地，当引导部514仅包括一个开孔514a时，L3等于L1。当引导部514包括多个开孔514a时，L3等于多个开孔514a沿第一方向X的尺寸L1之和。
折弯段511沿第一方向X的尺寸为L4。折弯段511沿第一方向X的尺寸L4等于第一层叠段512沿第一方向X的尺寸。每个第一层叠段512具有相对的两个第一边缘5121，第一边缘5121位于第一层叠段512沿第一方向X的两端。在第一方向X上，两个第一边缘5121的距离等于L4。第一极片51在展开状态时，L4的值即为第一极片51的宽度。折弯段511的尺寸L4等于所有开孔514a的尺寸L1与所有子折弯段511a的尺寸L2之和。
在一些实施例中，L3/L4的值越大，折弯段511越容易折弯，引导效果越好，同时折弯段511在折弯过程中断裂的风险越高；反之，L3/L4的值越小，折弯段511难折弯，引导效果越差，同时折弯段511的强度越高、越不容易在折弯的过程中断裂。发明人综合考虑子折弯段511a的折弯效果和强度，经过研究和试验后，发现当0.5≤L3/L4≤0.99时，能够在降低折弯段511断裂风险的前提下，提高折弯段511的折弯效果和引导部的引导效果。可选地，L3/L4的值为0.6、0.7、0.8和0.9。
L4越小，折弯段511的强度越低；当L4过小时，会造成引导部514的引导效果不明显。L4越大，越难保证折弯段511沿第一方向X的两端同步折弯。发明人经过 研究和试验后，发现当折弯段511的尺寸L4为200mm-1200mm时，折弯段511的折弯效果更好。
在一些实施例中，多个折弯段511包括第一折弯段和第二折弯段，第一折弯段和第二折弯段分别连接于第一层叠段512沿第二方向Y的两端，第一折弯段上的引导部514和第二折弯段上的引导部514沿第二方向Y的间距L5为80mm-200mm，第二方向Y垂直于第一方向X和层叠方向Z。第一极片51在展开状态时，相邻两个折弯段511的引导部514沿第一极片51的长度方向H的间距即为L5。在一些示例中，L5的值等于第一层叠段512沿第二方向Y的尺寸。
在第一极片51的折叠过程中，如果某个折弯段511因意外略微偏离了设定位置，可能造成与该折弯段511相连的第一层叠段512偏斜。在这种情况下，第一层叠段512的第一边缘5121与第二方向Y之间成一定的角度，L5的值越大，第一边缘5121在第一方向X偏离预定位置的最大值也就越大。在电极组件50容量一定的前提小，L5越小，第一极片51折叠的层数越多，第一层叠段512偏离设定位置的可能性越高。发明人经过研究和试验后，将L5的值设置为80mm-200mm，可以改善电极组件50的成型效果。
在一些实施例中，第一极片51在引导部514的引导下折弯后，与折弯段511相连接的两个相邻的第一层叠段512的第一边缘5121一致。在垂直与层叠方向Z的平面内，两个相邻的第一层叠段512同侧的第一边缘5121的正投影重合，即可认为这两个相邻的第一层叠段512的第一边缘5121一致。当然，由于工艺误差原因，在垂直与层叠方向Z的平面内，两个相邻的第一层叠段512的第一边缘5121的正投影之间也可以存在夹角，只要在层叠方向Z上第一层叠段512的第一活性物质层51b能够完全覆盖第二层叠段522的第二活性物质层52b，即可认为两个相邻的第一层叠段512的第一边缘5121一致。该夹角被称为允许误差角度。
图11为本申请另一个实施例的电极组件50的第一极片51在展开状态下的结构示意图。如图11所示，在一些实施例中，折弯段511包括两个开孔514a和一个子折弯段511a。子折弯段511a连接相邻的两个第一层叠段512。两个开孔514a分别位于子折弯段511a沿第一方向X的两侧。各开孔514a沿第一方向X的端部打开。在另一些实施例中，折弯段511也可仅包括一个开孔514a和一个子折弯段511a，开孔514a和子折弯段511a沿第一方向X设置。
在下文中，参照示例更详细地说明本公开的上述方面。然而，这些示例是示例性的，本公开不限于此。
(电极组件的制备)
示例1：
(i)将负极活性物质石墨或石墨与其它活性物质按不同质量比得到的混合物、导电剂乙炔黑、增稠剂CMC、粘结剂SBR按质量比96.4:1:1.2:1.4进行混合，加入溶剂去离子水，在真空搅拌机作用下搅拌至体系呈均一状，获得负极浆料；将负极浆料均匀涂覆在铜箔上，室温晾干后转移至烘箱继续干燥，然后经过冷压、分切、裁片得到第一极片51。负极浆料干燥固化后形成第一活性物质层51b。
(ii)使用在激光或模切刀具在第一极片51上形成开孔514a。开孔514a贯通第一极片51。图12为形成开孔514a后的第一极片51的示意图。如图12所示，第一极片51包括沿长度方向H交替设置的第一层叠段512和折弯段511，各折弯段511包括四个子折弯段511a和三个开孔514a，子折弯段511a和开孔514a沿第一方向X交替设置。各开孔514a沿第一方向X的尺寸L1为160mm，各子折弯段511a沿第一方向X的尺寸L2为20mm。折弯段511和第一层叠段512沿第一方向X的尺寸为560mm。第一层叠段512在第一极片51的长度方向H上的尺寸为88mm。折弯段511、子折弯段511a以及开孔514a在长度方向H上的尺寸w均为0.3mm。第一层叠段512的厚度Da和折弯段511的厚度均为0.18mm。第一层叠段512具有沿第一方向X相对设置的两个第一边缘5121以及在长度方向H相对设置的两个第二边缘5122。开孔514a与第二边缘5122相邻设置，图12中的虚线并不表示实体结构，可以示意性的作为第一层叠段512的第二边缘5122。第一边缘5121和第二边缘5122也是第一活性物质层51b的边缘。极耳513从一个第一边缘5121延伸。第一层叠段512为41个，折弯段511为40个。
(iii)提供两张隔离膜53，并将两张隔离膜53分别固定于第一极片51的两个表面。图13为固定在一起的第一极片51和隔离膜53的结构示意图。隔离膜53可通过热压、电泳或粘接等方式固定于第一极片51。隔离膜53为聚乙烯膜。隔离膜53的厚度Ds为0.01mm。
(iv)将正极活性物质NCM523、导电剂乙炔黑、粘结剂PVDF按质量比96:2:2进行混合，加入溶剂NMP，在真空搅拌机作用下搅拌至体系呈均一状，获得正极浆料；将粘结剂PVDF、绝缘材料三氧化二铝和溶剂混合在一起制备出保护浆料；将正极浆料和保护浆料均匀涂覆在铝箔上，室温晾干后转移至烘箱继续干燥，然后经过冷压、分切、裁片得到第二极片52。正极浆料固化后形成第二活性物质层52b，保护浆料固化后形成保护涂层52c。
(v)将多个第二极片52固定到隔离膜53上。图14为带状的电极组件50a的示意图，示出了固定在一起的第一极片51、第二极片52和隔离膜53。多个第二极片52可按照图14所示的方式布置第二极片52。第二极片52可通过热压、电泳或粘接等方式固定于隔离膜53。图15为带状的电极组件50a的局部俯视示意图，其示出了固定在一起的第一极片51、第二极片52和隔离膜53。如图15所示，第二极片52包括第二层叠段522和连接于第二层叠段522的第二极耳523，第二层叠段522包括沿第一方向相对设置的第三边缘5221和第四边缘5222，第二极耳523从第四边缘5222延伸。沿第一方向X，第二层叠段522的尺寸为558.5mm，具体地，在第一方向X上，第一层叠段512的一个第一边缘5121超出第三边缘1.5mm，第一层叠段512的另一个第一边缘5121与第四边缘5222齐平。保护涂层52c在第二层叠段522上的部分沿第一方向X的尺寸为1.5mm，也就是说，在第一方向X上，第一层叠段512的两个第一边缘5121均超出第二活性物质层1.5mm。第二层叠段522沿长度方向H的尺寸为86mm，第二层叠段522在长度方向H具有相对设置的两个第五边缘5223。在长度方向H上，第五边缘5223与第一层叠段512的第二边缘5122的距离为1mm。第二层叠段522的厚度Dc为0.25mm。第二极片52为40个。
(vi)对带状的电极组件50a进行折叠。图16示出了带状电极组件50a在折叠过程中的示意图。例如，可将带状的电极组件50a牵引到成型模具50b的上方，进入成型模具50b的型腔后，带状的电极组件50a在重力的作用下折叠。也可以利用其它辅助构件来帮助带状的电极组件50a折弯。
(vii)折叠完成后，对形成的电极组件进行热压，并缠绕胶带固定。
示例2：除了将开孔514a在长度方向H上的尺寸w变为0.27mm之外，根据与示例1相同的方法制造出电极组件。
示例3：除了将开孔514a在长度方向H上的尺寸w变为0.4mm之外，根据与示例1相同的方法制造出电极组件。
示例4：除了将开孔514a在长度方向H上的尺寸w变为0.5mm之外，根据与示例1相同的方法制造出电极组件。
示例5：除了将开孔514a在长度方向H上的尺寸w变为0.6mm之外，根据与示例1相同的方法制造出电极组件。
示例6：除了将开孔514a在长度方向H上的尺寸w变为0.7mm之外，根据与示例1相同的方法制造出电极组件。
示例7：除了将开孔514a在长度方向H上的尺寸w变为0.8mm之外，根据与示例1相同的方法制造出电极组件。
示例8：除了将开孔514a在长度方向H上的尺寸w变为0.9mm之外，根据与示例1相同的方法制造出电极组件。
对比示例1：除了将开孔514a在长度方向H上的尺寸w变为0.1mm之外，根据与示例1相同的方法制造出电极组件。
对比示例2：除了将开孔514a在长度方向H上的尺寸w变为0.2mm之外，根据与示例1相同的方法制造出电极组件。
对比示例3：除了将开孔514a在长度方向H上的尺寸w变为1mm之外，根据与示例1相同的方法制造出电极组件。
对比示例4：除了将开孔514a在长度方向H上的尺寸w变为1.2mm之外，根据与示例1相同的方法制造出电极组件。
评估示例：评估第一层叠段的边缘和第二层叠段的边缘的相对位置。
制造出根据示例1-8以及对比示例1-4的电极组件，并对其进行评估。
利用X射线CT扫描仪检测示例1-8以及对比示例1-4中的第一层叠段的各个边缘的位置和第二层叠段的各个边缘的位置。
图17为本申请一个实施例的电极组件的一局部剖视示意图。如图17所示，根据扫描仪检测出的图像，计算出各第二层叠段522的第三边缘5221与对应的第一层叠段512的一个第一边缘5121的在第一方向X上的最小间距D11。其中，D11即为第一活性物质层的一个边缘在第一方向X上超出第二活性物质层的一个边缘的尺寸。每个第二层叠段522与其两侧的第一层叠段512相比较，得到80个数值。
根据扫描仪检测出的图像，计算出各第二层叠段522的第四边缘5222与对应的第一层叠段512的另一个第一边缘5121的在第一方向X上的最小间距D12a。其中， D12a加上1.5mm，即为第一活性物质层的另一个边缘在第一方向X上超出第二活性物质层的另一个边缘的尺寸D12。每个第二层叠段522与其两侧的第一层叠段512相比较，得到80个数值。
图18为本申请一个实施例的电极组件的另一局部剖视示意图。如图18所示，根据扫描仪检测出的图像，计算出各第二层叠段522的第五边缘5223与对应的第一层叠段512的第二边缘5122的在第一方向X上的最小间距D13。每个第二层叠段522与其两侧的第一层叠段512相比较，得到160个数值。
其中，D11为正值，意味着第一活性物质层的一个边缘在第一方向X上超出第二活性物质层的一个边缘；D11为负值，意味着出第二活性物质层的一个边缘在第一方向X上超出第一活性物质层的一个边缘。D12、D13亦是如此。
示例1-8和对比示例1-4的评估结果示出于表1中。
(表1)
  w D11最小值 D12最小值 D13最小值
示例1 0.3mm 0.23mm 0.25mm 0.68mm
示例2 0.27mm 0.19mm 0.20mm 0.70mm
示例3 0.4mm 0.37mm 0.35mm 0.61mm
示例4 0.5mm 0.54mm 0.56mm 0.52mm
示例5 0.6mm 0.76mm 0.71mm 0.45mm
示例6 0.7mm 0.56mm 0.53mm 0.34mm
示例7 0.8mm 0.33mm 0.34mm 0.26mm
示例8 0.9mm 0.20mm 0.22mm 0.20mm
对比示例1 0.1mm -0.03mm -0.01mm 0.81mm
对比示例2 0.2mm 0.09mm 0.07mm 0.74mm
对比示例3 1.0mm 0.08mm 0.09mm 0.09mm
对比示例4 1.2mm -0.01mm -0.02mm -0.03mm
如表1所示，对于示例1-8的电极组件，w的值在0.27mm-0.9mm内，其满足关系式Dc+2Ds≤w≤2×(Dc+2Ds+Da)，且第一层叠段的第一活性物质层能够超出第二层叠段的第二活性物质层预定的尺寸，第一层叠段的第一活性物质层能够完全覆盖第二层叠段的第二活性物质层，为锂离子提供足够的嵌锂空间，减少析锂现象。而在对比示例1-4中，w的值偏大或偏小，这可能使第一层叠段的第一活性物质层无法完全超出第二层叠段的第二活性物质层、或者第一层叠段的第一活性物质层超出第二层叠段的第二活性物质层的尺寸过小；与示例1-8相比，对比示例1-4中的电极组件的析锂的风险更高。因此，与对比示例1-4中的电极组件相比，示例1-8中的电极组件的电化学性能更好，安全性更高。
图19为本申请一个实施例的一种电极组件的制造方法的示意性流程图。如图19所示，该制造方法包括：
S810，提供第一极片，第一极片包括多个折弯段和多个第一层叠段，每个折弯 段用于连接两个相邻的第一层叠段，折弯段具有引导部，引导部用于在生产时引导折弯段折弯；
S820，提供隔离膜，并将隔离膜固定于第一极片的两个表面，隔离膜包括多个隔离段；
S830，提供多个第二极片，第二极片与第一极片极性相反且包括第二层叠段，并将第二极片固定于隔离膜的背离第一极片的表面；
S840在引导部的引导下将折弯段折弯，以使多个第一层叠段层叠设置、每个第二极片的第二层叠段设置于相邻两个第一层叠段之间、每个隔离段设置于相邻的第一层叠段和第二层叠段之间。其中，在多个第一层叠段的层叠方向上，第一层叠段的厚度为Da，第二层叠段的厚度为Dc，隔离段的厚度为Ds，引导部在折弯段的弯折方向的尺寸为w，w、Da、Dc及Ds满足关系式：Dc+2Ds≤w≤2×(Dc+2Ds+Da)。
通过本实施例制造方法制造出的电极组件的相关结构，可以参考前述图1-18对应的实施例描述的电极组件的相关内容，在此不再赘述。
图20为本申请一个实施例的一种电池单体的制造系统的示意性框图。如图20所示，该制造系统900包括第一提供装置910、第二提供装置920、第一组装装置930、第三提供装置940、第二组装装置950以及第三组装装置960。第一提供装置910用于提供第一极片，第一极片包括多个折弯段和多个第一层叠段，每个折弯段用于连接两个相邻的第一层叠段，折弯段具有引导部，引导部用于在生产时引导折弯段折弯。第二提供装置920用于提供隔离膜，隔离膜包括多个隔离段。第一组装装置930用于将隔离膜固定于第一极片的两个表面。第三提供装置940用于提供多个第二极片，第二极片与第一极片极性相反且包括第二层叠段。第二组装装置950用于将第二极片固定于隔离膜的背离第一极片的表面。第三组装装置960用于在引导部的引导下将折弯段折弯，以使多个第一层叠段层叠设置、每个第二极片的第二层叠段设置于相邻两个第一层叠段之间、每个隔离段设置于相邻的第一层叠段和第二层叠段之间。其中，在多个第一层叠段的层叠方向上，第一层叠段的厚度为Da，第二层叠段的厚度为Dc，隔离段的厚度为Ds，引导部在折弯段的弯折方向的尺寸为w，w、Da、Dc及Ds满足关系式：Dc+2Ds≤w≤2×(Dc+2Ds+Da)。
通过本实施例制造系统制造出的电极组件的相关结构，可以参考前述图1-18对应的实施例描述的电极组件的相关内容，在此不再赘述。
最后应说明的是：以上实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换，但这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的精神和范围。

Claims (21)

  1. 一种电极组件，包括：
    第一极片，包括多个折弯段和多个层叠设置的第一层叠段，每个所述折弯段用于连接两个相邻的所述第一层叠段，所述折弯段具有引导部，所述引导部用于在生产时引导所述折弯段折弯；
    多个第二极片，所述第二极片与所述第一极片极性相反且包括第二层叠段，每个所述第二极片的所述第二层叠段设置于相邻两个所述第一层叠段之间；
    隔离膜，用于将所述第一极片和所述第二极片隔开，所述隔离膜包括多个隔离段，每个隔离段设置于相邻的第一层叠段和第二层叠段之间；
    其中，在多个所述第一层叠段的层叠方向上，所述第一层叠段的厚度为Da，所述第二层叠段的厚度为Dc，所述隔离段的厚度为Ds；
    所述引导部在所述折弯段的弯折方向的尺寸为w，w、Da、Dc及Ds满足关系式：
    Dc+2Ds≤w≤2×(Dc+2Ds+Da)。
  2. 根据权利要求1所述的电极组件，其中，所述引导部沿第一方向设置，所述第一方向与所述折弯段的弯折方向垂直。
  3. 根据权利要求2所述的电极组件，其中，所述引导部包括至少一个开孔。
  4. 根据权利要求3所述的电极组件，其中，所述开孔贯通所述折弯段。
  5. 根据权利要求3或4所述的电极组件，其中，所述折弯段包括多个子折弯段，所述子折弯段和所述开孔沿所述第一方向交替设置。
  6. 根据权利要求5所述的电极组件，其中，所述开孔沿所述第一方向的尺寸为L1，所述子折弯段沿所述第一方向的尺寸为L2，2≤L1/L2≤40。
  7. 根据权利要求3-6中任一项所述的电极组件，其中，所述引导部包括多个所述开孔，多个所述开孔间隔设置。
  8. 根据权利要求7所述的电极组件，其中，多个所述开孔沿所述第一方向间隔设置。
  9. 根据权利要求3-8中任一项所述的电极组件，所述开孔为圆形、椭圆形、跑道形或多边形。
  10. 根据权利要求2-9中任一项所述的电极组件，其中，所述引导部沿所述第一方向的尺寸为L3，所述折弯段沿所述第一方向的尺寸为L4，0.5≤L3/L4≤0.99。
  11. 根据权利要求10所述的电极组件，其中，所述折弯段沿所述第一方向的尺寸L4为200mm-1200mm。
  12. 根据权利要求2-11中任一项所述的电极组件，其中，多个所述折弯段包括第一折弯段和第二折弯段，所述第一折弯段和所述第二折弯段分别连接于所述第一层叠段沿第二方向的两端，所述第一折弯段上的所述引导部和所述第二折弯段上的所述引导部沿所述第二方向的间距L5为80mm-200mm，所述第二方向垂直于所述第一方向和所述层叠方向。
  13. 根据权利要求1-12中任一项所述的电极组件，其中，所述第一极片为负极极片， 所述第二极片为正极极片。
  14. 根据权利要求13所述的电极组件，其中，
    所述第一极片包括第一集流体和设置于所述第一集流体表面的第一活性物质层，所述第二极片包括第二集流体和设置于所述第二集流体表面的第二活性物质层；
    在所述层叠方向上，所述第一层叠段的所述第一活性物质层完全覆盖所述第二层叠段的所述第二活性物质层。
  15. 根据权利要求14所述的电极组件，其中，在垂直于所述层叠方向的方向上，所述第一层叠段的所述第一活性物质层至少超出所述第二层叠段的所述第二活性物质层0.1mm。
  16. 根据权利要求1-15中任一项所述的电极组件，其中，每个所述第一层叠段具有相对的两个第一边缘，在生产时引导所述折弯段折弯后，与所述折弯段相连接的两个相邻所述第一层叠段的所述第一边缘一致。
  17. 一种电池单体，包括：
    壳体，具有容纳腔和开口；
    至少一个如权利要求1-16中任一项所述的电极组件，容纳于所述容纳腔中；以及
    盖板，用于封闭所述壳体的开口。
  18. 一种电池，包括：
    箱体；
    至少一个如权利要求17所述的电池单体，所述电池单体收容于所述箱体内。
  19. 一种用电装置，所述用电装置被配置为接收从权利要求18所述的电池提供的电力。
  20. 一种电极组件的制造方法，包括：
    提供第一极片，所述第一极片包括多个折弯段和多个第一层叠段，每个所述折弯段用于连接两个相邻的所述第一层叠段，所述折弯段具有引导部，所述引导部用于在生产时引导所述折弯段折弯；
    提供隔离膜，并将所述隔离膜固定于所述第一极片的两个表面，所述隔离膜包括多个隔离段；
    提供多个第二极片，所述第二极片与所述第一极片极性相反且包括第二层叠段，并将所述第二极片固定于所述隔离膜的背离所述第一极片的表面；
    在所述引导部的引导下将所述折弯段折弯，以使多个第一层叠段层叠设置、每个所述第二极片的所述第二层叠段设置于相邻两个所述第一层叠段之间、每个隔离段设置于相邻的第一层叠段和第二层叠段之间；
    其中，在多个所述第一层叠段的层叠方向上，所述第一层叠段的厚度为Da，所述第二层叠段的厚度为Dc，所述隔离段的厚度为Ds，所述引导部在所述折弯段的弯折方向的尺寸为w，w、Da、Dc及Ds满足关系式：Dc+2Ds≤w≤2×(Dc+2Ds+Da)。
  21. 一种电极组件的制造系统，包括：。
    第一提供装置，用于提供第一极片，所述第一极片包括多个折弯段和多个第一层叠段，每个所述折弯段用于连接两个相邻的所述第一层叠段，所述折弯段具有引导部， 所述引导部用于在生产时引导所述折弯段折弯；
    第二提供装置，用于提供隔离膜，所述隔离膜包括多个隔离段；
    第一组装装置，用于将所述隔离膜固定于所述第一极片的两个表面；
    第三提供装置，用于提供多个第二极片，所述第二极片与所述第一极片极性相反且包括第二层叠段；
    第二组装装置，用于将所述第二极片固定于所述隔离膜的背离所述第一极片的表面；
    第三组装装置，用于在所述引导部的引导下将所述折弯段折弯，以使多个第一层叠段层叠设置、每个所述第二极片的所述第二层叠段设置于相邻两个所述第一层叠段之间、每个隔离段设置于相邻的第一层叠段和第二层叠段之间；其中，在多个所述第一层叠段的层叠方向上，所述第一层叠段的厚度为Da，所述第二层叠段的厚度为Dc，所述隔离段的厚度为Ds，所述引导部在所述折弯段的弯折方向的尺寸为w，w、Da、Dc及Ds满足关系式：Dc+2Ds≤w≤2×(Dc+2Ds+Da)。
PCT/CN2020/137717 2020-12-18 2020-12-18 电极组件及其制造方法和制造系统、电池单体、电池及用电装置 WO2022126634A1 (zh)

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