WO2023178593A1 - 极片、电极组件及其制造方法和装置、电池和用电装置 - Google Patents

极片、电极组件及其制造方法和装置、电池和用电装置 Download PDF

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Publication number
WO2023178593A1
WO2023178593A1 PCT/CN2022/082720 CN2022082720W WO2023178593A1 WO 2023178593 A1 WO2023178593 A1 WO 2023178593A1 CN 2022082720 W CN2022082720 W CN 2022082720W WO 2023178593 A1 WO2023178593 A1 WO 2023178593A1
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Prior art keywords
pole piece
along
electrode assembly
special
pole
Prior art date
Application number
PCT/CN2022/082720
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English (en)
French (fr)
Inventor
许虎
金海族
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/CN2022/082720 priority Critical patent/WO2023178593A1/zh
Priority to CN202280026785.2A priority patent/CN117121219A/zh
Priority to EP22932658.2A priority patent/EP4379837A1/en
Publication of WO2023178593A1 publication Critical patent/WO2023178593A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H01M10/0431—Cells with wound or folded electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—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
    • 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
    • H01M50/538—Connection of several leads or tabs of wound or folded electrode stacks
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present application relates to the field of battery technology, and in particular to a pole piece, an electrode assembly and a manufacturing method and device thereof, a battery and an electrical device.
  • lithium-ion and other batteries have the advantages of high energy density, high power density, multiple cycles, and long storage time, they have been widely used in electric vehicles.
  • the purpose of this application is to ensure the performance of the battery after long-term use.
  • a pole piece having a first end surface along a first direction, a second end surface along a second direction, and the second direction is perpendicular to the first direction;
  • At least one of the first end surface and the second end surface has a profiled surface, a partial area of the profiled surface along the third direction deviates from the reference plane, the reference plane is configured perpendicular to the first direction, and is located at the outermost side along the first direction through the profiled surface edge, the third direction is perpendicular to the first direction and the second direction.
  • At least one of the first end surface and the second end face is configured as a profiled surface, and the pole piece is rolled to form a multi-layered rolled electrode assembly, or multiple pole pieces are formed along a third direction.
  • thick right-angle steps can be avoided at the ends of the pole pieces. Since the battery cell will expand after long-term use, the electrode assembly will exert a force on the case, and at the same time, the case will exert a reaction force on the electrode assembly.
  • this application can improve the problem of stress concentration when receiving the reaction force exerted by the housing on the electrode assembly, prevent the end of the pole from shifting or deforming, and prevent the electrode assembly from deforming, thereby improving The active material on the pole piece falls off due to extrusion. Therefore, this improvement can ensure the performance of battery cells after long-term use.
  • the special-shaped surface is a plane and forms a preset angle with the reference plane, and the preset angle is not equal to 9°.
  • the special-shaped surface is set as a slope, so that the end of the pole piece forms a wedge shape.
  • the transmission to the adjacent layer pole piece can be reduced, and the local pressure at the end can be reduced.
  • Improve stress concentration phenomenon Moreover, the end of the pole piece is set as a bevel, the processing technology is simple, and it is easy to set the appropriate tilt angle according to the demand, and it is also easy to ensure the consistency of the tilt angle. In mass production, the consistency of the size of the pole piece can be ensured, thereby ensuring The battery cell performance is consistent.
  • the profiled surface curves and extends along the third direction.
  • the special-shaped surface is set as a curved surface, which can be flexibly set according to the stress concentration problems existing in different electrode assemblies during operation, the problem of burrs at the end of the pole piece damaging the diaphragm and causing short circuit, and the stress conditions at both ends of the pole piece along the thickness direction.
  • the end face shape of the pole piece enables the battery cell to maintain optimal performance after long-term operation.
  • the special-shaped surface is an arcuate surface that protrudes outward from the middle area along the third direction.
  • the special-shaped surface is set as a curved surface, which is easy to process and form.
  • the consistency of the size of the pole piece can be ensured, thereby ensuring consistent performance of the battery cells.
  • the special-shaped surface protrudes outward, which can reduce the contact between the two ends of the pole piece end surface in the thickness direction and the adjacent pole piece or housing, prevent burrs at the edge from damaging the diaphragm, and reduce the risk of short circuit in the electrode assembly during operation. ; And there are no sharp corners at the end of the pole piece, which can improve the overall strength of the end of the pole piece and greatly reduce the risk of the end of the pole piece breaking during assembly or battery use.
  • both sides of the pole piece end along the thickness direction will be in contact with other pole pieces or housings.
  • the outwardly protruding arc surface in the middle area can make the structure of both sides of the pole piece end along the thickness direction symmetrical, making the two sides of the pole piece end symmetrical. The stress is evenly distributed and stress concentration is reduced.
  • a transition angle is provided at an adjacent edge between the special-shaped surface and the side surface of the pole piece, and the side surface of the pole piece is perpendicular to the third direction.
  • a sharp portion can appear at the end of the pole piece, preventing burrs from being generated or the sharp portion damaging the diaphragm when being squeezed, and reducing the working time of the electrode assembly.
  • the risk of short circuit occurs during the process, and it can improve the strength of the pole piece end at the edge and reduce the risk of deformation of the pole piece end or active material falling off.
  • the transition angle the force transmitted from the end of the pole piece to the adjacent pole piece can be reduced, thereby reducing the overall deformation of the electrode assembly.
  • the pole pieces include:
  • the coating layer is provided on the side of the current collector along the third direction;
  • the special-shaped surface includes a first segmented surface and a second segmented surface.
  • the first segmented surface is located on the current collector, the second segmented surface is located on the coating layer, and the second segmented surface is relative to the first segmented surface along the first direction.
  • a segment is retracted inward by a preset distance.
  • a coating layer is provided on one side of the current collector at the end position, or no coating layer is provided on both sides, which can reduce the thickness of the step formed by the pole piece at the end position, so that the step portion can be protected when subjected to external force. Make the stress gradually change to avoid large stress.
  • the pole pieces include:
  • the coating layer is provided on the side of the current collector along the third direction;
  • the current collector includes a main body part and a lug part.
  • the lug part protrudes outward from the end surface of the main body part along the second direction.
  • the special-shaped surface is provided on the second end surface except for the area where the coating layer is not provided on the lug part.
  • the second end surface of the pole piece is thicker in the area where the coating layer is provided, and in the area where the coating layer is not provided on the tab part, only the thickness of the foil is thinner. Therefore, the special-shaped surface is provided on the second end surface without the tab part.
  • the area where the coating layer is not provided can not only prevent the formation of thick steps on the second end face, but also reduce the difficulty of processing.
  • the pole piece is a positive pole piece
  • the coating layer includes an active material layer and an insulating layer arranged side by side along the second direction.
  • the insulating layer is located on a side of the active material layer close to the pole tab along the second direction, and the special-shaped surface It is wrapped with a polymer produced by melting the insulation layer.
  • an electrode assembly including: a first pole piece and a second pole piece with opposite polarities, and at least one of the first pole piece and the second pole piece adopts the pole piece implemented above. .
  • the electrode assembly is a winding structure, and along the winding direction of the winding structure, at least one of the first starting end and the first end of the first pole piece and the second starting end and the second end of the second pole piece is One has a profiled surface.
  • the profiled surface is an inclined surface, and the profiled surface of at least one of the first end and the second end forms an acute angle with its inner surface along the radial direction of the winding structure; and/or at least one of the first starting end and the second starting end
  • the special-shaped surface forms an acute angle with its outer surface along the radial direction of the winding structure.
  • the first pole piece is a negative pole piece
  • the second pole piece is a positive pole piece
  • the second end surface of the first pole piece exceeds the second end surface of the second pole piece.
  • the end surface, the second end surface of the first pole piece has a special-shaped surface.
  • a battery cell including: a case having an opening; the electrode assembly of the above embodiment provided in the case; and an end cover assembly for closing the opening.
  • a battery including a case and the battery cell of the above embodiment, and the battery cell is disposed in the case.
  • an electrical device including the battery of the above embodiment, and the battery is used to provide electrical energy to the electrical device.
  • a method for manufacturing an electrode assembly including:
  • the step of providing pole pieces providing a first pole piece and a second pole piece with opposite polarities, at least one of the first pole piece and the second pole piece having the following structure pole piece: the pole piece has a first end surface along the first direction, There is a second end surface along the second direction, the second direction is perpendicular to the first direction, at least one of the first end surface and the second end surface has a profiled surface, a partial area of the profiled surface along the third direction deviates from the reference plane, and the reference plane is constructed It is perpendicular to the first direction and is located at the outermost edge along the first direction through the special-shaped surface, and the third direction is perpendicular to the first direction and the second direction;
  • Electrode forming step forming the first pole piece and the second pole piece into an electrode assembly.
  • a manufacturing equipment for an electrode assembly including:
  • a pole piece providing device is configured to provide a first pole piece and a second pole piece with opposite polarities. At least one of the first pole piece and the second pole piece is a pole piece with the following structure: the pole piece has a first pole piece along a first direction. One end face has a second end face along the second direction, and the second direction is perpendicular to the first direction. At least one of the first end face and the second end face has a special-shaped surface, and a partial area of the special-shaped surface along the third direction deviates from the reference plane.
  • Reference The plane is configured perpendicular to the first direction and is located along the outermost edge of the profiled surface along the first direction, and the third direction is perpendicular to the first direction and the second direction; and
  • a pole piece forming device configured to form the first pole piece and the second pole piece into an electrode assembly.
  • Figure 1 is a schematic structural diagram of some embodiments of the present application in which a battery is installed on a vehicle.
  • Figure 2 is an exploded view of some embodiments of the battery of the present application.
  • Figure 3 is a schematic structural diagram of some embodiments of battery cells of the present application.
  • Figure 4 is a front view of some embodiments of the flat electrode assembly of the present application.
  • Fig. 5 is a cross-sectional view along line A-A of Fig. 4 .
  • Fig. 6 is a cross-sectional view taken along line B-B in Fig. 4 .
  • Figure 7 is an enlarged view of C in Figure 6 .
  • Figure 8 is a schematic structural diagram of some embodiments of the negative electrode sheet of the present application.
  • Figure 9 is a schematic structural diagram of some embodiments of the positive electrode sheet of the present application.
  • Figure 10 is a side view of some embodiments of the application in which the special-shaped surface of the pole piece is a bevel.
  • Figure 11 is a schematic diagram of the force-bearing principle of the pole piece shown in Figure 10.
  • Figure 12 is a side view of the pole piece of the present application, where the special-shaped surface is an arc surface.
  • Figure 13 is a side view of the pole piece of the present application with a transition surface at the edge of the special-shaped surface.
  • Figure 14 is a side view of the coating layer in the pole piece of the present application retracting inwards by a preset distance relative to the current collector.
  • Figure 15 is a schematic end view of some embodiments of the cylindrical electrode assembly of the present application.
  • Figure 16 is an enlarged view of C in Figure 12 .
  • Figure 17 is an enlarged view of D in Figure 12 .
  • Figure 18 is a schematic flowchart of some embodiments of the electrode assembly manufacturing method of the present application.
  • Figure 19 is a schematic diagram of the module composition of some embodiments of the electrode assembly manufacturing device of the present application.
  • Pole piece 101. First end face; 102. Second end face; 102A, first end face section; 102B, second end face section; 102C, third end face section; 102D, fourth end face section; 11. Current collector; 111. Main body part; 112. Pole ear part; 12. Coating layer; 121. Active material layer; 122. Insulating layer; 13. Transition angle; N, special-shaped surface; N1, first segmented surface; N2, second Segmented surface; P, reference plane;
  • Electrode assembly 100', electrode body; 100A, straight section; 100B, turning section; 110, first pole piece, 120, second pole piece; 130, diaphragm; 112A, first pole tab; 112B, first pole piece Diode lug; K, winding axis; S1, first end; S2, second end; E1, first beginning end; E2, second beginning end;
  • Manufacturing device 510. Equipment for providing pole pieces; 520. Equipment for forming pole pieces.
  • multiple refers to more than two (including two).
  • multiple groups refers to two or more groups (including two groups), and “multiple pieces” refers to It is more than two pieces (including two pieces).
  • connection should be understood in a broad sense.
  • it can be a fixed connection or a removable connection.
  • an embodiment means that a particular feature, structure or characteristic described in connection with the embodiment can be included in at least some embodiments of the present application.
  • the appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those skilled in the art understand, both explicitly and implicitly, that the embodiments described herein may be combined with other embodiments.
  • 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 shape of a cylinder, a flat body, a rectangular parallelepiped or other shapes, and the embodiments of the present application are not limited to this.
  • Battery cells are generally divided into three types according to packaging methods: cylindrical battery cells, square battery cells and soft-pack battery cells, and the embodiments of the present application are not limited to this.
  • Current battery cells usually include a casing and an electrode assembly housed in the casing, and the casing is filled with electrolyte.
  • the electrode assembly is mainly formed by laminating or winding a first pole piece and a second pole piece with opposite polarities, and usually a separator is provided between the first pole piece and the second pole piece.
  • the coated portions of the first pole piece and the second pole piece constitute the main body of the electrode assembly, and the uncoated portions of the first pole piece and the second pole piece respectively constitute the first pole tab and the second pole tab.
  • the first electrode sheet may be a positive electrode sheet, including a positive electrode current collector and a positive electrode coating layer provided on both sides of the positive electrode current collector.
  • the material of the positive electrode current collector may be, for example, aluminum, and the positive electrode coating may be, for example, cobalt. Lithium acid phosphate, lithium iron phosphate, ternary lithium or lithium manganate, etc.; the second pole piece can be a negative electrode piece, including a negative electrode current collector and negative electrode coating layers provided on both sides of the negative electrode current collector.
  • the material of the negative electrode current collector can be, for example It is copper, and the negative electrode coating can be, for example, graphite or silicon.
  • the first pole tab and the second pole tab may be located together at one end of the main body part or respectively located at both ends of the main body part.
  • the reason why the electrode assembly produces the above phenomenon is that the electrode assembly will expand during use. After the expansion, it will exert a force on the shell, and at the same time, the shell will exert a reaction force on the electrode assembly. Since the cutting edges of the pole pieces are all at right angles, the first pole piece and the second pole piece will form right-angled steps at the winding end and the winding beginning.
  • the pole piece There will be a problem of stress concentration at the winding end, causing the winding end to shift or deform. Under the extrusion of the shell, the active material will fall off. Moreover, the stress concentration in the outer layer will be transferred to the inner layer, causing the entire electrode assembly to deform, causing the starting end of the winding to shift or deform, and may also cause the central hole to collapse.
  • the positive electrode sheet is sandwiched between adjacent negative electrode sheets.
  • the end of the positive electrode sheet along the width direction has a right-angle step, it is often Stress concentration problems will also occur under the extrusion of the layer pole piece.
  • the battery cells in the embodiments of the present application are suitable for batteries and electrical devices using batteries.
  • Electrical devices can be mobile phones, portable devices, laptops, battery cars, electric cars, ships, spacecraft, electric toys and power tools, etc.
  • spacecraft include airplanes, rockets, space shuttles, spaceships, etc.
  • electric toys Including fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc.
  • Power tools include metal cutting power tools, grinding power tools, assembly power tools and railway power tools.
  • the electrical device can be a vehicle 400, such as a new energy vehicle.
  • the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc.; or the electrical device can also be a drone or a ship, etc.
  • the vehicle 400 may include an axle 401, wheels 402 connected to the axle 401, a motor 403, a controller 404 and a battery 300.
  • the motor 403 is used to drive the axle 401 to rotate, and the controller 404 is used to control the operation of the motor 403.
  • the battery 300 may be disposed at the bottom, head, or tail of the vehicle 400 to provide electrical energy for the operation of the motor 403 and other components in the vehicle.
  • the battery 300 includes a case 301 and a battery cell 200 .
  • the battery 300 there may be one battery cell 200 or a plurality of battery cells 200. If there are multiple battery cells 200, the multiple battery cells 200 can be connected in series, in parallel, or in mixed connection. Mixed connection means that the multiple battery cells 200 are both connected in series and in parallel, and they can be multiple battery cells. 200 are first connected in series, parallel or mixed to form a battery module, and then multiple battery modules are connected in series, parallel or mixed to form a whole, and are accommodated in the box 301 . Alternatively, all the battery cells 200 may be directly connected in series, in parallel, or mixed together, and then the entire battery cell 200 may be accommodated in the box 301 .
  • the interior of the box 301 is a hollow structure.
  • the box 301 may include a receiving body 301A and a cover 301B.
  • the accommodating body 301A and the cover body 301B are fastened together.
  • both the accommodation body 301A and the cover body 301B can be hollow rectangular parallelepipeds with only one open surface.
  • the opening of the accommodation body 301A and the opening of the cover body 301B are arranged oppositely, and the accommodation body 301A and the cover body 301B are interlocked to form a A box that closes the chamber.
  • the container 301A is a rectangular parallelepiped with an opening and the cover 301B is plate-shaped, or the cover 301B is a rectangular parallelepiped with an opening and the container 301A is plate-shaped, and the container 301A and the cover 301B are arranged oppositely and locked together.
  • At least one battery cell 200 is connected in parallel or in series or in a mixed combination, and then placed in a closed chamber formed by the fastening of the accommodation body 301A and the cover 301B.
  • the battery cell 200 may be, for example, a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium lithium ion battery, a magnesium ion battery, or the like.
  • the battery cell 200 includes a casing 210 , an electrode assembly 100 , an end cap assembly 220 and two adapters 230 .
  • the casing 210 has an opening, and the end cap assembly 220 closes the opening and
  • the electrode assembly 100 is connected to the case 210 to form the outer shell of the battery cell 200 .
  • the electrode assembly 100 is disposed in the case 210 , and the case 210 is filled with electrolyte.
  • the electrode assembly 100 can be provided as a single or multiple electrodes.
  • the electrode assembly 100 is formed by stacking or winding a first pole piece and a second pole piece with opposite polarities, and usually a separator is provided between the first pole piece and the second pole piece.
  • the coated portions of the first pole piece and the second pole piece constitute the electrode body 100' of the electrode assembly 100, and the uncoated portions of the first pole piece and the second pole piece respectively constitute the first tabs 112A and 112A.
  • the second pole lug 112B is formed by stacking or winding a first pole piece and a second pole piece with opposite polarities, and usually a separator is provided between the first pole piece and the second pole piece.
  • the coated portions of the first pole piece and the second pole piece constitute the electrode body 100' of the electrode assembly 100, and the uncoated portions of the first pole piece and the second pole piece respectively constitute the first tabs 112A and 112A.
  • the second pole lug 112B is formed by stacking or winding a
  • FIG. 4 is a front view of the wound electrode assembly 100.
  • the first tab 112A and the second tab 112B can be led out from the same end of the electrode body 100' along the winding axis K, or they can They are respectively drawn out from both ends of the electrode body 100' along the winding axis K.
  • FIG 5 is an A-A cross-sectional view of the electrode assembly 100 shown in Figure 4.
  • the electrode assembly 100 is flat and has two parallel straight sections 100A arranged oppositely and two oppositely arranged turning sections 100B.
  • the turning section 100B is connected to the two flat sections 100A.
  • the electrode assembly 100 is formed by rolling a first pole piece 110 , a second pole piece 120 and a separator 130 to form a rolled structure.
  • the separator 130 is located between the first pole piece 110 and the second pole piece 120 .
  • the first pole piece 110 has a first starting end E1 and a first end S1
  • the second pole piece 120 has a second starting end E2 and a second end S2.
  • FIG. 6 is a B-B cross-sectional view of the electrode assembly 100 shown in FIG. 4 .
  • the first pole pieces 110 and the second pole pieces 120 are alternately arranged. If the first pole piece 110 is a negative pole piece and the second pole piece 120 is a positive pole piece, the end surface of the first pole piece 110 along the winding axis K exceeds the second pole piece 120 .
  • FIG. 7 is an enlarged view of A in FIG. 6 .
  • the first pole piece 110 and the second pole piece 120 both include a current collector 11 and a coating layer 12 disposed on the side of the current collector 11 along its thickness direction. Both sides of the current collector 11
  • the coating layer 12 can be provided on both sides. For the innermost or outermost pole piece, the coating layer 12 can be provided only on one side of the current collector 11 .
  • the current collector 11 may include a main body portion 111 and a tab portion 112 protruding outward from an end surface of the main body portion 111 along the winding axis K.
  • the plurality of pole tab portions 112 of the first pole piece 110 are stacked to form the first pole tab 112A, and the plurality of pole tab portions 112 of the second pole piece 120 are stacked.
  • the arrangement forms the second tab 112B.
  • FIG. 8 is a schematic structural diagram of the first pole piece 110.
  • the first pole piece 110 is a negative pole piece.
  • the current collector 11 can be copper
  • the coating layer 12 can be a negative active material, which can be graphite or silicon. If the length direction of the first pole piece 110 is defined as the first direction x, and its width direction is defined as the second direction y, the coating width of the coating layer 12 along the second direction y exceeds the edge of the main body portion 111 to cover the pole.
  • FIG. 9 is a schematic structural diagram of the second pole piece 120.
  • the first pole piece 120 is a positive pole piece.
  • the current collector 11 may be made of aluminum, and the coating layer 12 may include an active material layer 121 and an insulating layer 122 arranged side by side along the second direction y.
  • the insulating layer 122 is located along the second direction y on the active material layer 121 close to the tab 112
  • the active material layer 121 may be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganate.
  • the thickness of the insulating layer 122 can be thinner than that of the active material layer 121, and a bevel transition is used at the connection.
  • the insulating layer 122 By arranging the insulating layer 122 and positioning the end of the main body portion 111 of the negative electrode sheet close to the tab portion 112 along the winding axis K direction in the area where the insulating layer 122 is located, it is possible to satisfy the requirement that the active material layer 121 of the negative electrode exceeds the limit along the winding axis K. On the basis of the active material layer 121 of the adjacent positive electrode, the risk of short-circuiting between the positive electrode sheet and the negative electrode sheet after metal chips penetrate the separator 130 is reduced.
  • the pole piece 110 may be the first pole piece 110 or the second pole piece 120 mentioned above.
  • the pole piece 10 has a first end surface 101 along the first direction x and a second end surface 102 along the second direction y, and the second direction y is perpendicular to the first direction x.
  • At least one of the first end surface 101 and the second end surface 102 has a profiled surface N, and a partial area of the profiled surface N along the third direction z deviates from the reference plane P.
  • the reference plane P is configured perpendicular to the first direction x, and is formed by the profiled surface N.
  • the surface N is located at the outermost edge along the first direction x, and the third direction z is perpendicular to the first direction x and the second direction y.
  • the pole piece 10 is generally in the shape of a long strip, and the pole piece 10 can be a positive pole piece as shown in FIG. 4 or a negative pole piece as shown in FIG. 5 .
  • the first direction x and the second direction y can be located in a plane perpendicular to the thickness direction of the pole piece 10 , and the first direction x can be the length direction or width direction of the pole piece 10 , and the third direction z is the same as the thickness of the pole piece 10 Same direction.
  • the two end surfaces 102 extend along the first direction x and are not provided with tab portions 112.
  • the second end surface 102 on the other side is provided with tab portions 112 in a zigzag shape.
  • the first direction x is the width direction, the positions of the first end surface 101 and the second end surface 102 are reversed.
  • the pole piece 10 can be cut and formed at the first end face 101 and the second end face 102, or it can also be directly formed according to the required size through other methods.
  • At least one of the first end surface 101 and the second end surface 102 has a special-shaped surface N, that is, one, two or three of the two first end surfaces 101 and the two second end surfaces 102 are provided.
  • is a special-shaped surface N and the other end surfaces are set as planes perpendicular to the side of the pole piece 10 (that is, extending along the third direction z); or the four end surfaces are all set as special-shaped surfaces N.
  • the entire end face can be set as the special-shaped surface, or only a part of the end face can be set as the special-shaped surface N.
  • the reference plane P is configured to be perpendicular to the first direction x and located at the outermost edge along the first direction x through the profiled surface N.
  • the third direction z is perpendicular to the first direction x and the second direction y. Partial areas in the three directions z deviate from the reference plane P, where "deviating from the reference plane P" means not coinciding with the reference plane P, or there is a gap between the reference plane P and the reference plane P.
  • the pole piece 10 of this embodiment at least one of the first end surface 101 and the second end surface 102 is configured as a profiled surface N, and the pole piece 10 is rolled to form a multi-layered rolled electrode assembly 100, or multiple When the pole pieces 10 are stacked along the third direction z to form the laminated electrode assembly 100, the formation of thick right-angle steps at the ends of the pole pieces 10 can be avoided.
  • the electrode assembly 100 After the battery cell 200 is used for a long time, the electrode assembly 100 will expand, and the expansion will exert a force on the casing 210, and at the same time, the casing 210 will exert a reaction force on the electrode assembly 100.
  • the present application can improve the stress concentration problem when receiving the reaction force exerted by the housing 210 on the electrode assembly 100, prevent the end of the pole piece 10 from positional deviation or deformation, and prevent the electrode from being displaced or deformed.
  • the component 100 is deformed, thereby improving the phenomenon that the active material on the pole piece 10 falls off due to being squeezed. Therefore, this improvement can ensure the performance of the battery cell 200 after long-term use.
  • the pole piece 10 is used to form a wound electrode assembly 100. If the two first end faces 101 of the positive pole piece and the negative pole piece are both configured as profiled faces N, the problem of stress concentration at the beginning and end of the positive pole piece and the negative pole piece can be improved. It can reduce the deflection or deformation of the winding start end and the winding end, and prevent the central hole of the winding from collapsing due to the overall deformation of the electrode assembly 100; in addition, it can also improve the occurrence of the active material on the pole piece 10 due to extrusion. The phenomenon of shedding.
  • the second end surface 102 of the positive electrode sheet is configured as a special-shaped surface N, since the width of the negative electrode sheet exceeds the positive electrode sheet at the end of the electrode assembly 100 along the winding direction K, the positive electrode sheet is sandwiched between adjacent negative electrode sheets, which can improve the performance of the positive electrode.
  • the problem of stress concentration in the area where the second end face 102 of the positive electrode piece is located prevents the second end face 102 of the positive electrode piece from being deformed due to being squeezed by the adjacent negative electrode piece, and improves the risk of the active material on the electrode piece 10 falling off due to being squeezed. Phenomenon.
  • the special-shaped surface N is a plane and forms a preset angle ⁇ with the reference plane P, and the preset angle ⁇ is not equal to 90°. If the angle between the special-shaped surface N itself and the reference plane P is defined as the preset angle ⁇ , then ⁇ is an acute angle.
  • the first pole piece 110 is located outside the second pole piece 120. If the outside of the first pole piece 110 is subjected to a force F during the battery operation or assembly process, the force F acts on the bevel portion. cannot be transmitted to the second pole piece 120, and only the force F" acting on the largest part of the thickness of the first pole piece 110 can be transmitted to the second pole piece 120. Therefore, the end of the first pole piece 110 due to the special-shaped surface N The existence increases the stress-bearing area of the steps in this region, thereby reducing the local pressure and thereby improving the stress concentration phenomenon.
  • the special-shaped surface N is set as a slope, so that the end of the pole piece 10 forms a wedge shape.
  • the transmission to the adjacent layer pole piece 10 can be reduced, and the end force can be reduced. Local pressure can improve stress concentration.
  • the end of the pole piece 10 is set as a bevel, the processing technology is simple, and it is easy to set the appropriate tilt angle according to the demand, and it is also easy to ensure the consistency of the tilt angle, and the consistency of the size of the pole piece 10 can be ensured during mass production. This ensures consistent performance of the battery cells 200 .
  • the profiled surface N extends curvedly along the third direction z.
  • the special-shaped surface N can form a continuous curved surface along the entire third direction z, and the curved surface can be any non-planar surface.
  • the special-shaped surface N may be convex toward the outside of the end of the pole piece 10 , or may be concave inward, or a curved surface having both concave and convex shapes may be used. If the special-shaped surface N protrudes outward, the two ends of the end surface of the pole piece 10 along the thickness direction can be reduced from contacting the adjacent pole piece 10 or the housing 210 , preventing burrs at the edge from damaging the diaphragm 130 , and reducing the risk of the electrode assembly 100 Risk of short circuit during work.
  • the contact area between the end of the pole piece 10 and the surface of the adjacent pole piece 10 or the housing 210 can be increased, thereby increasing the supporting force and reducing the end pressure, thereby improving the stress concentration problem.
  • the special-shaped surface N is set as a curved surface, which can solve the problem of stress concentration when working with different electrode assemblies 100, the problem of burrs at the end of the pole piece damaging the diaphragm 130 and causing a short circuit, and the stress conditions at both ends of the pole piece 10 along the thickness direction. , flexibly set the end face shape of the pole piece 10 so that the battery cell 200 can still maintain optimal performance after long-term operation.
  • the special-shaped surface N is an arcuate surface that protrudes outward from the middle area along the third direction z.
  • the arc surface may be a circular arc surface or other shapes.
  • the profiled surface N deviates from the reference plane P along both sides in the thickness direction of the pole piece 10 .
  • the special-shaped surface N is set as a curved surface, which is easy to process and form.
  • the size consistency of the pole piece 10 can be ensured, thereby ensuring consistent performance of the battery cells 200 .
  • the shaped surface N protrudes outward, which can reduce the contact of the two ends of the end surface of the pole piece 10 along the thickness direction with the adjacent pole piece 10 or the housing 210, prevent burrs at the edge from damaging the diaphragm 130, and reduce the risk of the electrode assembly 100 The risk of short circuit occurs during work; and there are no sharp corners at the end of the pole piece 10, which can improve the overall strength of the end of the pole piece 10 and greatly reduce the breakage of the end of the pole piece 10 during assembly or battery use.
  • both sides of the end of the pole piece 10 along the thickness direction are in contact with other pole pieces or the housing 210.
  • the outwardly protruding arc surface in the middle area can make the structure of both sides of the end of the pole piece 10 along the thickness direction symmetrical. It can make the stress distribution on both sides even and reduce the stress concentration.
  • the adjacent edge between the profiled surface N and the side surface of the pole piece 10 is provided with a transition angle 13, and the side surface of the pole piece 10 is perpendicular to the third direction z.
  • the transition angle 13 may be rounded or bevelled.
  • the pole piece 10 includes: a current collector 11 and a coating layer 12 , and the coating layer 12 is disposed on the side of the current collector 11 along the third direction z.
  • the special-shaped surface N includes a first segmented surface N1 and a second segmented surface N2.
  • the first segmented surface N1 is located on the current collector 11, the second segmented surface N2 is located on the coating layer 12, and the second segmented surface N2 is located on the coating layer 12.
  • N2 is retracted inwardly by a predetermined distance relative to the first segmented surface N1 along the first direction x.
  • the special-shaped surface N is a stepped surface formed by the first segmented surface N1 and the second segmented surface N2.
  • the second segmented surface N2 can be perpendicular to the surface where the current collector 11 and the coating layer 12 are bonded, or opposite to The surface where the current collector 11 and the coating layer 12 are bonded is inclined.
  • the special-shaped surface N forms a step surface in the thickness direction of the pole piece 10.
  • the coating layer 12 on one or both sides can be made inward relative to the current collector 11. Retract the preset distance.
  • the coating layer 12 on the outside can be retracted inward by a preset distance, so that the insulating film 130 on the outside of the pole piece 10 can be covered with a slope structure. While reducing the thickness of the step at the end of the pole piece 10, there is no need to apply external force to the end of the pole piece 10 to make it fit with the inner pole piece 10, thereby reducing the deformation of the end of the pole piece 10.
  • a protective layer may be provided at the end position.
  • a coating layer 12 is provided on one side of the current collector 11 at the end position, or no coating layer 12 is provided on both sides, which can reduce the thickness of the step formed at the end position of the pole piece 10 so that the step portion is at When subjected to external force, the stress can be gradually changed to avoid generating larger stress.
  • the pole piece 10 includes: a current collector 11 and a coating layer 12 , and the coating layer 12 is disposed on the side of the current collector 11 along the third direction z.
  • the current collector 11 includes a main body part 111 and a tab part 112.
  • the tab part 112 protrudes outward from the end surface of the main body part 111 along the second direction y.
  • the special-shaped surface N is provided on the second end surface 102 except that the tab part 112 is not provided with a coating. area of cladding 12.
  • the area of the second end surface 102 except for the tab portion 112 where the coating layer 12 is not provided includes: the first end surface segment 102A between the adjacent tab portions 112 on the main body portion 111 , and the two outermost sections on the main body portion 111 .
  • the second end surface section 102B outside the pole lug portion 112 and the third end surface section 102C of the coating layer 12 are provided at the root of the pole lug portion 112 .
  • the second end surface 102 also includes: a fourth end surface section 102D in which the lug portion 112 is not provided with the coating layer 12 .
  • the second end surface 102 has a sawtooth structure.
  • the second end surface 102 of the pole piece 10 Since the second end surface 102 of the pole piece 10 is thicker in the area where the coating layer 12 is provided, and in the area where the coating layer 12 is not provided on the pole tab 112, only the thickness of the foil is thinner. Therefore, the special-shaped surface N is provided on the second end surface 102 of the pole piece 10 .
  • the area of the two end surfaces 102 where the coating layer 12 is not provided except the tab portion 112 can not only prevent the formation of a thick step on the second end surface 102, but also reduce the difficulty of processing.
  • the pole piece 10 is a positive pole piece
  • the coating layer 12 includes an active material layer 121 and an insulating layer 122 arranged side by side along the second direction y.
  • the insulating layer 122 is located near the active material layer 121 along the second direction y.
  • the special-shaped surface N is wrapped with a polymer produced by melting the insulating layer.
  • the materials used for the insulating layer 122 may include inorganic fillers and adhesives.
  • the inorganic filler includes one of boehmite, alumina, magnesium oxide, titanium dioxide, zirconia, silicon dioxide, silicon carbide, boron carbide, calcium carbonate, aluminum silicate, calcium silicate, potassium titanate, barium sulfate, or Several kinds.
  • the binder includes one or more of polyvinylidene fluoride, polyacrylonitrile, polyacrylic acid, polyacrylate, polyacrylic acid-acrylate, polyacrylonitrile-acrylic acid, and polyacrylonitrile-acrylate.
  • the insulating layer 122 close to the second end surface 102 will melt, and the generated polymer will be wrapped around the special-shaped surface N. It can protect the special-shaped surface N, prevent metal powder or active material powder from being produced on the die-cut surface, and prevent it from falling into the electrode assembly 100 during assembly or use and causing a short circuit. A short circuit occurs when the diaphragm 130 is punctured during assembly or use.
  • the flat wound electrode assembly 100 shown in FIG. 4 to FIG. 9 is taken as an example for description.
  • the electrode assembly 100 includes: a first pole piece 110 and a second pole piece 120 with opposite polarities. At least one of the first pole piece 110 and the second pole piece 120 adopts the pole piece 10 of the above embodiment.
  • the special-shaped surface N may be provided only on the end surface of the first pole piece 110, or the special-shaped surface N may be provided only on the end surface of the second pole piece 120, or both the first pole piece 110 and the second pole piece 120 may be provided with special-shaped surface N. Surface N to achieve the best effect of alleviating stress concentration.
  • the electrode assembly 100 has a winding structure.
  • the first starting end E1 and the first end S1 of the first pole piece 110 and the second pole piece 110 have a winding structure.
  • At least one of the second starting end E2 and the second end S2 of 120 is provided with a profiled surface N. If the first direction x is defined as the length direction of the pole piece 10, then the first end surface 101 is provided with a special-shaped surface N.
  • the housing 210 will Applying a reaction force to the outermost pole piece 10 of the electrode assembly 100, by setting the special-shaped surface N, can avoid forming a thick step at the first end S1 or the second end S2, and alleviate the stress concentration caused by the extrusion of the housing 210.
  • reducing the deflection or deformation of the end of the pole piece 10 can also improve the phenomenon of the active material falling off due to extrusion on the pole piece 10; in addition, the reduction of the stress on the outer layer can reduce the stress transmitted to the inner layer, thereby The overall deformation of the electrode assembly 100 is alleviated. If the special-shaped surface N is provided at the starting end of the first pole piece 110 and/or the second pole piece 120, when the force exerted by the housing 210 on the electrode assembly 100 is transmitted to the inner layer, the offset or deformation of the starting end can be reduced, and Reducing the shedding of active material on the pole piece 10 can also prevent the central hole of the electrode assembly 100 from collapsing.
  • the profiled surface N is a slope, and the profiled surface N of at least one of the first end S1 and the second end S2 forms an acute angle with its inner surface along the radial direction of the winding structure; and/or The profiled surface N of at least one of the first end E1 and the second start end E2 forms an acute angle with its outer surface along the radial direction of the winding structure.
  • the special-shaped surface N is formed by its inner surface along the radial direction of the winding structure.
  • the acute angle facilitates the insulation film 130 located on the outermost side of the electrode assembly 100 to cover the slope structure formed by the acute angle.
  • the first end S1 or the second end S2 can be connected with the inner electrode.
  • the piece 10 fits naturally without applying external force to the first end S1 or the second end S2 to make it fit with the inner pole piece 10, which can reduce the deformation of the first end S1 or the second end S2 and prevent the pole piece from being deformed.
  • the ends of 10 are pressed inward to cause damage to the diaphragm 130, thereby improving the reliability and safety of the electrode assembly 100 during operation.
  • the contact between the first starting end E1 or the second starting end E2 and the adjacent outer layer pole piece 10 can be increased. area, increase the supporting force of the adjacent outer pole piece 10 to the first starting end E1 or the second starting end E2, so that the starting end is not easy to tilt, reducing the possibility of end deviation or deformation, and improving the working performance of the electrode assembly 100 time reliability and safety.
  • the first pole piece 110 is a negative pole piece
  • the second pole piece 120 is a positive pole piece.
  • the first pole piece 110 The second end surface 102 exceeds the second end surface 102 of the second pole piece 120 , and the second end surface 102 of the first pole piece 110 has a profiled surface N.
  • the second end surface 102 of the first pole piece 110 has a special shape.
  • Surface N can improve the problem of stress concentration in the area where the second end face 102 of the positive electrode piece is located, prevent the second end face 102 of the positive electrode piece from being deformed due to the extrusion of the adjacent negative electrode piece, and improve the active material on the electrode piece 10 due to The electrode assembly 100 may fall off when being squeezed, thereby improving the performance of the electrode assembly 100 during use.
  • Figure 15 is a cylindrical electrode assembly 100.
  • Figure 16 is an enlarged view of D in Figure 15.
  • the second starting end E2 of the second pole piece 120 is provided with a special-shaped surface N.
  • the special-shaped surface N It is an inclined surface, and the line connecting the winding center and the outermost end of the special-shaped surface N is used as the reference plane P.
  • the inclined surface and the reference plane P form an included angle ⁇ 1.
  • the first starting end E1 of the first pole piece 120 is not provided with the special-shaped surface N.
  • Figure 17 is an enlarged view of E in Figure 15.
  • the first end S1 of the first pole piece 110 and the second end S2 of the second pole piece 120 are both provided with a special-shaped surface N.
  • the special-shaped surface N is an inclined plane, with the winding center
  • the line connected to the outermost end of the special-shaped surface N serves as the reference plane P.
  • the special-shaped surface N at the first end S1 forms an angle ⁇ 2 with the reference plane P.
  • the special-shaped surface N at the second end S2 forms an included angle with the reference plane P. ⁇ 3.
  • this application provides a manufacturing method of the electrode assembly 100, as shown in Figure 15.
  • the manufacturing method includes:
  • Step of providing pole pieces providing a first pole piece 110 and a second pole piece 120 with opposite polarities. At least one of the first pole piece 110 and the second pole piece 120 has the following structure pole piece 10: the pole piece 10 has an edge along The first direction x has a first end surface 101, and the second direction y has a second end surface 102. The second direction y is perpendicular to the first direction x, and at least one of the first end surface 101 and the second end surface 102 has a special-shaped surface N, A partial area of the special-shaped surface N along the third direction z deviates from the reference plane P.
  • the reference plane P is configured to be perpendicular to the first direction x and is located at the outermost edge of the special-shaped surface N along the first direction x.
  • the third direction z is vertical.
  • the special-shaped surface N can be formed by cutting with a tool.
  • Electrode forming step form the first pole piece 110 and the second pole piece 120 into the electrode assembly 100.
  • the electrode assembly 100 may be formed by rolling or laminating.
  • the manufacturing method of this embodiment sets at least one of the first end surface 101 and the second end surface 102 of the pole piece 10 as a profiled surface N, and forms a multi-layered rolled electrode assembly 100 on the pole piece 10 by winding, or
  • the stress concentration when receiving the reaction force exerted by the housing 210 on the electrode assembly 100 can be improved.
  • the problem is to prevent the end of the pole piece 10 from being displaced or deformed, and to prevent the electrode assembly 100 from being deformed, thereby improving the phenomenon that the active material on the pole piece 10 falls off due to extrusion. Therefore, this improvement can ensure the performance of the battery cell 200 after long-term use.
  • the manufacturing device 500 includes: a pole piece providing device 510 and a pole piece forming device 520.
  • the pole piece providing device 510 is configured to provide the first pole piece 110 and the second pole piece 120 with opposite polarity.
  • At least one of the first pole piece 110 and the second pole piece 120 is the pole piece 10 with the following structure:
  • the sheet 10 has a first end surface 101 along the first direction x and a second end surface 102 along the second direction y.
  • the second direction y is perpendicular to the first direction x.
  • At least one of the first end surface 101 and the second end surface 102 has a special shape Surface N, the partial area of the special-shaped surface N along the third direction z deviates from the reference plane P.
  • the reference plane P is constructed perpendicular to the first direction x and is located at the outermost edge of the special-shaped surface N along the first direction x.
  • the third The direction z is perpendicular to the first direction x and the second direction y.
  • Pole piece forming apparatus 520 is configured to form first pole piece 110 and second pole piece 120 into electrode assembly 100 .

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Abstract

本申请实施例提供一种极片、电极组件及其制造方法和装置、电池和用电装置，其中，极片第一方向(x)具有第一端面(101)，沿第二方向(y)具有第二端面(102)，第二方向(y)垂直于第一方向(x)；第一端面(101)和第二端面(102)中的至少一个具有异形面(N)，异形面(N)沿第三方向(z)的部分区域偏离参考平面(P)，参考平面(P)被构造为垂直于第一方向(x)，且通过异形面(N)沿第一方向(x)位于最外侧的边缘，第三方向(z)垂直于第一方向(x)和第二方向(y)。

Description

极片、电极组件及其制造方法和装置、电池和用电装置 技术领域
本申请涉及电池技术领域，特别是涉及一种极片、电极组件及其制造方法和装置、电池和用电装置。
背景技术
由于锂离子等电池具有能量密度高、功率密度高、循环使用次数多、存储时间长等优点，在电动汽车上面已普遍应用。
但是，提高电动汽车中电池在长期使用的工作性能，一直是业内的一个难题。
发明内容
本申请的目的在于保证电池长期使用后的性能。
根据本申请的第一方面，提供了一种极片，沿第一方向具有第一端面，沿第二方向具有第二端面，第二方向垂直于第一方向；
第一端面和第二端面中的至少一个具有异形面，异形面沿第三方向的部分区域偏离参考平面，参考平面被构造为垂直于第一方向，且通过异形面沿第一方向位于最外侧的边缘，第三方向垂直于第一方向和第二方向。
该实施例的极片通过将第一端面和第二端面中的至少一个设置为异形面，在极片通过卷绕形成多层层叠的卷绕式电极组件，或者多个极片沿第三方向叠加形成叠片式电极组件时，可避免在极片的端部形成较厚的直角台阶。由于电池单体在长期使用后，电极组件会发生膨胀，在膨胀后会对壳体施加作用力，同时壳体对电极组件施加反作用力。本申请通过减小极片端部的厚度，可改善在受到壳体施加于电极组件的反作用力时的应力集中问题，防止极片端部发生位置偏移或变形，并防止电极组件发生变形，从而改善极片上活性物质由于受到挤压发生脱落的现象。因此，此种改进能够保证电池单体在长期使用后的性能。
在一些实施例中，异形面为平面，且与参考平面之间形成预设角度，预设角度不等于9°。
该实施例将异形面设置为斜面，使极片的端部形成楔形，在极片的端部在受到作用力时可减少向相邻层极片传递，可减小端部的局部压强，能够改善应力集中现象。而 且，将极片的端部设置为斜面，加工工艺简单，且便于根据需求设置合适的倾斜角度，也易于保证倾斜角度的一致性，在批量生产时可保证极片尺寸的一致性，从而保证电池单体性能一致。
在一些实施例中，异形面沿第三方向弯曲延伸。
该实施例将异形面设置为曲面，可根据不同电极组件在工作时存在的应力集中问题、极片端部毛刺损伤隔膜发生短路的问题、以及极片沿厚度方向两端的受力情况，灵活地设置极片的端面形状，以使电池单体在长期工作后仍能保持较优的性能。
在一些实施例中，异形面为沿第三方向的中间区域向外凸出的弧面。
该实施例将异形面设置为弧面，易于加工成形，在采用在批量生产时可保证极片尺寸的一致性，从而保证电池单体性能一致。而且，异形面向外凸出，可使极片端面沿厚度方向的两端减少与相邻极片或壳体接触，防止边缘部分产生毛刺损伤隔膜，降低了电极组件在工作过程中发生短路的风险；且极片的端部不存在尖角部分，可提高极片端部的整体强度，大大降低了极片的端部在装配或电池使用过程中发生断裂的风险。此外，极片端部沿厚度方向的两侧均会与其它极片或壳体接触，中间区域向外凸出的弧面可使极片端部沿厚度方向的两侧结构对称，可使两侧的应力分布均匀，减小应力集中。
在一些实施例中，异形面与极片的侧面之间邻接的边缘设有过渡角，极片的侧面垂直于第三方向。
该实施例通过在异形面与极片的侧面的连接处设置过渡角，能够使极片的端部出现尖锐部，防止产生毛刺或在受到挤压时尖锐部损伤隔膜，降低了电极组件在工作过程中发生短路的风险，而且能提高极片端部在边缘部分的强度，减小极片端部发生变形或活性物质脱落的风险。此外，通过设置过渡角，可减小极片端部向相邻极片传递作用力，从而减小电极组件的整体变形量。
在一些实施例中，极片包括：
集流体；和
涂覆层，沿第三方向设置于集流体的侧面；
其中，异形面包括第一分段面和第二分段面，第一分段面位于集流体上，第二分段面位于涂覆层上，第二分段面沿第一方向相对于第一分段面向内缩回预设距离。
该实施例在集流体的端部位置单面设置涂覆层，或者双面均不设置涂覆层，可减小极片在端部位置形成的台阶厚度，以使台阶部位在受到外力时可使应力发生渐变，以免产生较大的应力。
在一些实施例中，极片包括：
集流体；和
涂覆层，沿第三方向设置于集流体的侧面；
集流体包括主体部和极耳部，极耳部从主体部沿第二方向的端面向外凸出，异形面设置于第二端面除去极耳部未设置涂覆层的区域。
由于极片的第二端面在设置涂覆层的区域较厚，而在极耳部未设置涂覆层的区域只有箔片的厚度较薄，因此，异形面设置于第二端面除去极耳部未设置涂覆层的区域，既能防止在第二端面形成较厚的台阶，又能降低加工难度。
在一些实施例中，极片为正极片，涂覆层包括沿第二方向并排设置的活性物质层和绝缘层，绝缘层沿第二方向位于活性物质层靠近极耳部的一侧，异形面上包裹有绝缘层熔融后产生的聚合物。
在采用激光模切出异形面时会产生热量，对于靠近极耳部一侧的第二端面，靠近第二端面的绝缘层会发生熔化，产生的聚合物包裹在异形面上，能够对异形面形成保护，防止模切断面产生金属粉末或活性物质粉末，在装配或使用时落入电极组件中发生短路，还可防止模切端面产生尖锐部位或毛刺，以免在装配或使用时刺破隔膜发生短路。
根据本申请的第二方面，提供了一种电极组件，包括：极性相反的第一极片和第二极片，第一极片和第二极片中的至少一个采用上述实施的极片。
在一些实施例中，电极组件为卷绕结构，沿卷绕结构的卷绕方向，第一极片的第一始端和第一末端、第二极片的第二始端和第二末端中的至少一个设有异形面。
在一些实施例中，异形面为斜面，第一末端和第二末端中至少一个的异形面与其沿卷绕结构径向的内侧面形成锐角；和/或第一始端和第二始端中至少一个的异形面与其沿卷绕结构径向的外侧面形成锐角。
在一些实施例中，第一极片为负极片，第二极片为正极片，在与第二方向一致的卷绕轴线上，第一极片的第二端面超出第二极片的第二端面，第一极片的第二端面具有异形面。
根据本申请的第三方面，提供了一种电池单体，包括：壳体，具有开口；上述实施例的电极组件，设在壳体内；和端盖组件，用于封闭开口。
根据本申请的第四方面，提供了一种电池，包括：箱体和上述实施例的电池单体，电池单体设在箱体内。
根据本申请的第五方面，提供了一种用电装置，包括上述实施例的电池，电池用于为用电装置提供电能。
根据本申请的第六方面，提供了一种电极组件的制造方法，包括：
极片提供步骤：提供极性相反的第一极片和第二极片，第一极片和第二极片中的至少一个为如下结构极片：极片沿第一方向具有第一端面，沿第二方向具有第二端面，第二方向垂直于第一方向，第一端面和第二端面中的至少一个具有异形面，异形面沿第三方向的部分区域偏离参考平面，参考平面被构造为垂直于第一方向，且通过异形面沿第一方向位于最外侧的边缘，第三方向垂直于第一方向和第二方向；
电极成形步骤：将第一极片和第二极片形成电极组件。
根据本申请的第七方面，提供了一种电极组件的制造设备，包括：
极片提供设备，被配置为提供极性相反的第一极片和第二极片，第一极片和第二极片中的至少一个为如下结构极片：极片沿第一方向具有第一端面，沿第二方向具有第二端面，第二方向垂直于第一方向，第一端面和第二端面中的至少一个具有异形面，异形面沿第三方向的部分区域偏离参考平面，参考平面被构造为垂直于第一方向，且通过异形面沿第一方向位于最外侧的边缘，第三方向垂直于第一方向和第二方向；和
极片成形设备，被配置为将第一极片和第二极片形成电极组件。
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为本申请将电池安装于车辆的一些实施例的结构示意图。
图2为本申请电池的一些实施例的分解图。
图3为本申请电池单体的一些实施例的结构示意图。
图4为本申请扁平式电极组件的一些实施例的主视图。
图5为图4的A-A剖视图。
图6为图4的B-B剖视图。
图7为图6的C处放大图。
图8为本申请负极片的一些实施例的结构示意图。
图9为本申请正极片的一些实施例的结构示意图。
图10为本申请极片的异形面为斜面一些实施例的侧视图。
图11为图10所示极片的受力原理示意图。
图12为本申请极片的异形面为圆弧面的侧视图。
图13为本申请极片在异形面边缘设置过渡面的侧视图。
图14为本申请极片中涂覆层相对于集流体向内缩回预设距离的侧视图。
图15为本申请圆柱形电极组件的一些实施例的端面示意图。
图16为图12的C处放大图。
图17为图12的D处放大图。
图18为本申请电极组件制造方法的一些实施例的流程示意图。
图19为本申请电极组件制造装置的一些实施例的模块组成示意图。
在附图中，附图并未按照实际的比例绘制。
标记说明：
10、极片；101、第一端面；102、第二端面；102A、第一端面段；102B、第二端面段；102C、第三端面段；102D、第四端面段；11、集流体；111、主体部；112、极耳部；12、涂覆层；121、活性物质层；122、绝缘层；13、过渡角；N、异形面；N1、第一分段面；N2、第二分段面；P、参考平面；
100、电极组件；100’、电极主体；100A、平直段；100B、转弯段；110、第一极片、120、第二极片；130、隔膜；112A、第一极耳；112B、第二极耳；K、卷绕轴线；S1、第一末端；S2、第二末端；E1、第一始端；E2、第二始端；
200、电池单体；210、壳体；220、端盖组件；221、端盖本体；222、电极端子；230、转接件；
300、电池；301、箱体；301A、容纳体；301B、盖体；
400、车辆；401、车桥；402、车轮；403、马达；404、控制器；
500、制造装置；510、极片提供设备；520、极片成形设备。
具体实施方式
下面结合附图和实施例对本申请的实施方式作进一步详细描述。以下实施例的详细描述和附图用于示例性地说明本申请的原理，但不能用来限制本申请的范围，即本申请不限于所描述的实施例。
在本申请实施例的描述中，术语“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)。
本申请采用了“上”、“下”、“顶”、“底”、“前”、“后”、“内”和“外”等指示的方位或位置关系的描述，这仅是为了便于描述本申请，而不是指示或暗示所指的装置必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申 请保护范围的限制。
此外，术语“第一”、“第二”、“第三”等仅用于描述目的，而不能理解为指示或暗示相对重要性。“垂直”并不是严格意义上的垂直，而是在误差允许范围之内。“平行”并不是严格意义上的平行，而是在误差允许范围之内。下述描述中出现的方位词均为图中示出的方向，并不是对本申请的具体结构进行限定。
在本申请的描述中，还需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是直接相连，也可以通过中间媒介间接相连。对于本领域的普通技术人员而言，可视具体情况理解上述术语在本申请中的具体含义。
在本文中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一些实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。本领域技术人员显式地和隐式地理解的是，本文所描述的实施例可以与其它实施例相结合。
电池单体可以包括锂离子二次电池、锂离子一次电池、锂硫电池、钠锂离子电池、钠离子电池或镁离子电池等，本申请实施例对此并不限定。电池单体可呈圆柱体、扁平体、长方体或其它形状等，本申请实施例对此也不限定。电池单体一般按封装的方式分成三种：柱形电池单体、方形电池单体和软包电池单体，本申请实施例对此也不限定。
目前的电池单体通常包括壳体和容纳于壳体内的电极组件，并在壳体内填充电解质。电极组件主要由极性相反的第一极片和第二极片层叠或卷绕形成，并且通常在第一极片与第二极片之间设有隔膜。第一极片和第二极片涂覆有涂覆的部分构成电极组件的主体部，第一极片和第二极片未涂覆涂覆的部分各自构成第一极耳和第二极耳。在锂离子电池中，第一极片可以为正极片，包括正极集流体和设于正极集流体两侧的正极涂覆层，正极集流体的材料例如可以为铝，正极涂覆例如可以为钴酸锂、磷酸铁锂、三元锂或锰酸锂等；第二极片可以为负极片，包括负极集流体和设于负极集流体两侧的负极涂覆层，负极集流体的材料例如可以为铜，负极涂覆例如可以为石墨或硅等。第一极耳和第二极耳可以共同位于主体部的一端或是分别位于主体部的两端。在电池单体的充放电过程中，正极涂覆和负极涂覆与电解液发生反应，极耳连接电极端子以形成电流回路。
目前的电池在长期使用后，会出现性能下降和工作可靠性较差的问题，发明人通过研究发现，例如，对于卷绕式电极组件，造成该问题的主要原因在于极片的卷绕始端和卷绕末端会发生偏移，造成卷绕末端或卷绕始端产生变形，或者电极组件的中心孔塌陷；此外，极片上的活性物质也会发生脱落现象。
通过分析，电极组件产生上述现象的原因在于，电极组件在使用过程中会发生膨胀，在膨胀后会对壳体施加作用力，同时壳体对电极组件施加反作用力。由于极片的裁切边均为直角，第一极片和第二极片在卷绕末端和卷绕始端都会形成直角台阶，在电极组件的外层受到壳体的反作用力时，极片的卷绕末端会出现应力集中的问题，使卷绕末端发生偏移或变形，在壳体的挤压作用下，会造成活性物质脱落。而且，外层的应力集中会朝向内层传递，造成整个电极组件发生变形，使卷绕始端也发生偏移或变形，还可能使中心孔塌陷。
同样的，在电极组件沿卷绕方向的端部，由于负极片的宽度超出正极片，正极片夹在相邻负极片之间，在正极片沿宽度方向的端部具有直角台阶时，也多层极片的挤压下也会出现应力集中问题。
为了解决电池在长期使用后极片出现应力集中的问题，发明人想到通过改变极片自身的结构从根本上缓解应力集中，此种方式无需对电池单体的内部结构进行改进。
本申请实施例的电池单体适用于电池以及使用电池的用电装置。
用电装置可以是手机、便携式设备、笔记本电脑、电瓶车、电动汽车、轮船、航天器、电动玩具和电动工具等等，例如，航天器包括飞机、火箭、航天飞机和宇宙飞船等等，电动玩具包括固定式或移动式的电动玩具，例如，游戏机、电动汽车玩具、电动轮船玩具和电动飞机玩具等等，电动工具包括金属切削电动工具、研磨电动工具、装配电动工具和铁道用电动工具，例如，电钻、电动砂轮机、电动扳手、电动螺丝刀、电锤、冲击电钻、混凝土振动器和电刨。
如图1所示，用电装置可以是车辆400，例如新能源汽车，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；或者用电装置也可以是无人机或轮船等。具体地，车辆400可包括车桥401、连接于车桥401的车轮402、马达403、控制器404和电池300，马达403用于驱动车桥401转动，控制器404用于控制马达403工作，电池300可以设置在车辆400的底部、头部或尾部，用于为马达403以及车辆中其它部件的工作提供电能。
如图2所示，电池300包括箱体301和电池单体200。在电池300中，电池单体200可以是一个，也可以是多个。若电池单体200为多个，多个电池单体200之间可串联或并联或混联，混联是指多个电池单体200中既有串联又有并联，可以是多个电池单体200先串联或并联或混联组成电池模块，多个电池模块再串联或并联或混联形成一个整体，并容纳于箱体301内。也可以是所有电池单体200之间直接串联或并联或混联在一起，再将所有电池单体200构成的整体容纳于箱体301内。
箱体301内部为中空结构，例如，箱体301可以包括容纳体301A和盖体301B。容纳体301A和盖体301B扣合在一起。例如，容纳体301A和盖体301B均可以为中空长方体且各自只有一个面为开口面，容纳体301A的开口和盖体301B的开口相对设置，并且容纳体301A和盖体301B相互扣合形成具有封闭腔室的箱体。也可以为，容纳体301A为具有开口的长方体而盖体301B为板状，或者盖体301B为具有开口的长方体而容纳体301A为板状，容纳体301A和盖体301B相对设置并扣合而形成具有封闭腔室的箱体。至少一个电池单体200相互并联或串联或混联组合后，置于容纳体301A和盖体301B扣合后形成的封闭腔室内。
电池单体200例如可以为锂离子二次电池、锂离子一次电池、锂硫电池、钠锂离子电池或镁离子电池等。
在一些实施例中，如图3所示，电池单体200包括壳体210、电极组件100、端盖组件220和两个转接件230，壳体210具有开口，端盖组件220封闭开口并与壳体210连接形成电池单体200的外壳，电极组件100设在壳体210内，且壳体210内填充电解液。
根据实际使用需求，电极组件100可设置为单个或多个。电极组件100由极性相反的第一极片和第二极片层叠或卷绕形成，并且通常在第一极片与第二极片之间设有隔膜。第一极片和第二极片涂覆有涂覆的部分构成电极组件100的电极主体100’，第一极片和第二极片未涂覆涂覆的部分各自构成第一极耳112A和第二极耳112B。
例如，在锂离子电池中，图4为卷绕式电极组件100的主视图，第一极耳112A和第二极耳112B可从电极主体100’沿卷绕轴线K的同一端引出，也可从电极主体100’沿卷绕轴线K的两端分别引出。
图5为图4所示电极组件100的A-A剖视图，电极组件100呈扁平状，具有两个平行相对设置的平直段100A和两个相对设置的转弯段100B，转弯段100B连接与两个平直段100A的同一端。电极组件100由第一极片110、第二极片120和隔膜130卷绕形成卷绕结构，隔膜130位于第一极片110和第二极片120之间。沿卷绕结构的卷绕方向，第一极片110具有第一始端E1和第一末端S1，第二极片120具有第二始端E2和第二末端S2。
图6为图4所示电极组件100的B-B剖视图，在同一平直段100A中，第一极片110和第二极片120交替设置。若第一极片110为负极片，第二极片120为正极片，第一极片110沿卷绕轴线K的端面超出第二极片120。
图7为图6的A处放大图，第一极片110和第二极片120均包括集流体11和沿其厚度方向设置于集流体11侧面的涂覆层12，集流体11的两侧可都设置涂覆层12，对于最内层或最外层极片，可仅在集流体11的单侧设置涂覆层12。集流体11可包括主体部 111和极耳部112，极耳部112从主体部111沿卷绕轴线K的端面向外凸出。在第一极片110和第二极片120卷绕后，第一极片110的多个极耳部112层叠设置形成第一极耳112A，第二极片120的多个极耳部112层叠设置形成第二极耳112B。
图8为第一极片110的结构示意图，例如，第一极片110为负极片。集流体11可采用铜，涂覆层12为负极活性物质，可以为石墨或硅等。如果将第一极片110的长度方向定义为第一方向x，并将其宽度方向定义为第二方向y，涂覆层12沿第二方向y的涂覆宽度超出主体部111的边缘覆盖极耳部112的根部。
图9为第二极片120的结构示意图，例如，第一极片120为正极片。集流体11可采用铝，涂覆层12可包括沿第二方向y并排设置的活性物质层121和绝缘层122，绝缘层122沿所述第二方向y位于活性物质层121靠近极耳部112的一侧，活性物质层121可采用钴酸锂、磷酸铁锂、三元锂或锰酸锂等。绝缘层122的厚度可薄于活性物质层121，并在连接处采用斜面过渡。通过设置绝缘层122，并使负极片的主体部111沿卷绕轴线K方向靠近极耳部112的端部位于绝缘层122所在区域，能够在满足负极的活性物质层121沿卷绕轴线K超出相邻的正极的活性物质层121的基础上，降低金属屑刺破隔膜130后正极片和负极片发生短路的风险。
下面将详细介绍极片10的结构，极片110可以为前面提到的第一极片110或第二极片120。
在一些实施例中，如图10所示，极片10沿第一方向x具有第一端面101，沿第二方向y具有第二端面102，第二方向y垂直于第一方向x。第一端面101和第二端面102中的至少一个具有异形面N，异形面N沿第三方向z的部分区域偏离参考平面P，参考平面P被构造为垂直于第一方向x，且通过异形面N沿第一方向x位于最外侧的边缘，第三方向z垂直于第一方向x和第二方向y。
其中，极片10大致呈长条带状结构，极片10可以为图4所示的正极片或图5所示的负极片。第一方向x和第二方向y可位于垂直于极片10厚度方向所在的平面内，且第一方向x可以为极片10的长度方向或宽度方向，第三方向z与极片10的厚度方向一致。
例如，若第一方向x为长度方向，第一端面101可以为极片10沿长度方向的两个端面，第二端面102可以为极片10沿宽度方向的两个端面，其中一侧的第二端面102沿第一方向x延伸且未设置极耳部112，另一侧的第二端面102设有极耳部112呈锯齿状。若第一方向x为宽度方向，第一端面101和第二端面102的位置反之。极片10可在第一端面101和第二端面102位置裁切形成，或者也可通过其它方式直接按照需要的尺寸形成。
如图10所示，第一端面101和第二端面102中的至少一个具有异形面N，即两个 第一端面101和两个第二端面102中的其中一个、两个、三个端面设置为异形面N，而其它端面设置为垂直于极片10侧面(即沿第三方向z延伸)的平面；或者四个端面均设置为异形面N。可选地，在设置异形面N的端面上，可整个端面设置为异形面，或者只将端面的部分区域设置为异形面N。
参考平面P被构造为垂直于第一方向x，且通过异形面N沿第一方向x位于最外侧的边缘，第三方向z垂直于第一方向x和第二方向y，异形面N沿第三方向z的部分区域偏离参考平面P，其中，“偏离参考平面P”是指与参考平面P不重合，或者与参考平面P之间存在间隔。
该实施例的极片10通过将第一端面101和第二端面102中的至少一个设置为异形面N，在极片10通过卷绕形成多层层叠的卷绕式电极组件100，或者多个极片10沿第三方向z叠加形成叠片式电极组件100时，可避免在极片10的端部形成较厚的直角台阶。由于电池单体200在长期使用后，电极组件100会发生膨胀，在膨胀后会对壳体210施加作用力，同时壳体210对电极组件100施加反作用力。本申请通过减小极片10端部的厚度，可改善在受到壳体210施加于电极组件100的反作用力时的应力集中问题，防止极片10端部发生位置偏移或变形，并防止电极组件100发生变形，从而改善极片10上活性物质由于受到挤压发生脱落的现象。因此，此种改进能够保证电池单体200在长期使用后的性能。
例如，极片10用于形成卷绕式电极组件100，若正极片和负极片的两个第一端面101均设置为异形面N，可改善正极片和负极片各自的始端和末端应力集中的问题，可减少卷绕始端和卷绕末端发生偏移或变形，还可防止由于电极组件100整体变形导致卷绕的中心孔塌陷；此外，还可改善极片10上活性物质由于受到挤压发生脱落的现象。若正极片的第二端面102设置为异形面N，由于在电极组件100沿卷绕方向K的端部，负极片的宽度超出正极片，正极片夹在相邻负极片之间，可改善正极片在第二端面102所在区域出现应力集中的问题，防止正极片的第二端面102由于受到相邻负极片的挤压而发生变形，并改善极片10上活性物质由于受到挤压发生脱落的现象。
在一些实施例中，如图10所示，异形面N为平面，且与参考平面P之间形成预设角度θ，预设角度θ不等于90°。如果将异形面N本身与参考平面P之间的夹角定义为预设角度θ，则θ为锐角。
如图11所示，第一极片110位于第二极片120外侧，若第一极片110外侧在电池工作过程中或装配过程中受到作用力F时，作用于斜角部分的作用力F不能传递到第二极片120，只有作用于第一极片110厚度最大部分的作用力F”才能传递至第二极片120，由 此，第一极片110的端部由于异形面N的存在使该区域台阶的受力面积增大，从而减小了局部压强，进而改善应力集中现象。
该实施例将异形面N设置为斜面，使极片10的端部形成楔形，在极片10的端部在受到作用力时可减少向相邻层极片10传递，可减小端部的局部压强，能够改善应力集中现象。而且，将极片10的端部设置为斜面，加工工艺简单，且便于根据需求设置合适的倾斜角度，也易于保证倾斜角度的一致性，在批量生产时可保证极片10尺寸的一致性，从而保证电池单体200性能一致。
在一些实施例中，异形面N沿第三方向z弯曲延伸。
例如，异形面N可沿整个第三方向z形成连续的曲面，曲面可以为任意的非平面。
例如，异形面N可以朝向极片10的端部外侧凸出，或者也可向内凹入，也可采用同时具有凹凸形状的曲面。若异形面N向外凸出，则可使极片10端面沿厚度方向的两端减少与相邻极片10或壳体210接触，防止边缘部分产生毛刺损伤隔膜130，降低了电极组件100在工作过程中发生短路的风险。若异形面N向内凹入，则可增大极片10端部与相邻极片10表面或壳体210的接触面积，从而增加支撑力，减小端部压强，从而改善应力集中问题。
该实施例将异形面N设置为曲面，可根据不同电极组件100在工作时存在的应力集中问题、极片端部毛刺损伤隔膜130发生短路的问题、以及极片10沿厚度方向两端的受力情况，灵活地设置极片10的端面形状，以使电池单体200在长期工作后仍能保持较优的性能。
在一些实施中，如图12所示，异形面N为沿第三方向z的中间区域向外凸出的弧面。该弧面可以为圆弧面或其它形状。对于该结构，异形面N沿在极片10厚度方向上的两侧区域偏离基准平面P。
该实施例将异形面N设置为弧面，易于加工成形，在采用在批量生产时可保证极片10尺寸的一致性，从而保证电池单体200性能一致。而且，异形面N向外凸出，可使极片10端面沿厚度方向的两端减少与相邻极片10或壳体210接触，防止边缘部分产生毛刺损伤隔膜130，降低了电极组件100在工作过程中发生短路的风险；且极片10的端部不存在尖角部分，可提高极片10端部的整体强度，大大降低了极片10的端部在装配或电池使用过程中发生断裂的风险。此外，极片10端部沿厚度方向的两侧均会与其它极片或壳体210接触，中间区域向外凸出的弧面可使极片10端部沿厚度方向的两侧结构对称，可使两侧的应力分布均匀，减小应力集中。
在一些实施例中，如图13所示，异形面N与极片10的侧面之间邻接的边缘设有 过渡角13，极片10的侧面垂直于第三方向z。例如，过渡角13可以为圆角或斜角。
该实施例通过在异形面N与极片10的侧面的连接处设置过渡角13，能够使极片10的端部出现尖锐部，防止产生毛刺或在受到挤压时尖锐部损伤隔膜130，降低了电极组件100在工作过程中发生短路的风险，而且能提高极片10端部在边缘部分的强度，减小极片10端部发生变形或活性物质脱落的风险。此外，通过设置过渡角13，可减小极片10端部向相邻极片10传递作用力，从而减小电极组件100的整体变形量。
在一些实施例中，如图14所示，极片10包括：集流体11和涂覆层12，涂覆层12沿第三方向z设置于集流体11的侧面。其中，异形面N包括第一分段面N1和第二分段面N2，第一分段面N1位于集流体11上，第二分段面N2位于涂覆层12上，第二分段面N2沿第一方向x相对于第一分段面N1向内缩回预设距离。
对于该结构，异形面N为第一分段面N1和第二分段面N2形成的阶梯面，第二分段面N2可以垂直于集流体11与涂覆层12贴合的表面，或者相对于集流体11与涂覆层12贴合的表面倾斜设置。异形面N在极片10厚度方向上形成阶梯面，对于集流体11两侧均设置涂覆层12的极片10，可使一侧或两侧的涂覆层12相对于集流体11向内缩回预设距离。若极片10端部位于电极组件100的最外层，可将位于外侧的涂覆层12向内缩回预设距离，这样可使极片10外侧的绝缘膜130包覆为斜坡结构，在减小极片10端部台阶厚度的同时，无需向极片10端部施加外力使其与内层极片10贴合，可减小极片10端部的变形。
例如，在涂布涂覆层12时，可在端部位置设置保护层。
该实施例在集流体11的端部位置单面设置涂覆层12，或者双面均不设置涂覆层12，可减小极片10在端部位置形成的台阶厚度，以使台阶部位在受到外力时可使应力发生渐变，以免产生较大的应力。
在一些实施例中，极片10包括：集流体11和涂覆层12，涂覆层12沿第三方向z设置于集流体11的侧面。集流体11包括主体部111和极耳部112，极耳部112从主体部111沿第二方向y的端面向外凸出，异形面N设置于第二端面102除去极耳部112未设置涂覆层12的区域。
其中，第二端面102除去极耳部112未设置涂覆层12的区域包括：主体部111上位于相邻极耳部112之间的第一端面段102A、主体部111上位于最外侧两个极耳部112之外的第二端面段102B、以及极耳部112根部设置涂覆层12的第三端面段102C。除此之外，第二端面102还包括：极耳部112未设置涂覆层12的第四端面段102D。在极耳部112所在侧，第二端面102呈锯齿结构。
由于极片10的第二端面102在设置涂覆层12的区域较厚，而在极耳部112未设置涂覆层12的区域只有箔片的厚度较薄，因此，异形面N设置于第二端面102除去极耳部112未设置涂覆层12的区域，既能防止在第二端面102形成较厚的台阶，又能降低加工难度。
在一些实施例中，极片10为正极片，涂覆层12包括沿第二方向y并排设置的活性物质层121和绝缘层122，绝缘层122沿第二方向y位于活性物质层121靠近极耳部112的一侧，对于靠近极耳部112一侧的第二端面102，异形面N上包裹有绝缘层熔融后产生的聚合物。
例如，绝缘层122采用的材料可包括：无机填料和粘接剂。无机填料包括勃姆石、氧化铝、氧化镁、二氧化钛、氧化锆、二氧化硅、碳化硅、碳化硼、碳酸钙、硅酸铝、硅酸钙、钛酸钾、硫酸钡中的一种或几种。粘结剂包括聚偏氟乙烯、聚丙烯腈、聚丙烯酸、聚丙烯酸酯、聚丙烯酸-丙烯酸酯、聚丙烯腈-丙烯酸、聚丙烯腈-丙烯酸酯中的一种或几种。
在采用激光模切出异形面N时会产生热量，对于靠近极耳部112一侧的第二端面102，靠近第二端面102的绝缘层122会发生熔化，产生的聚合物包裹在异形面N上，能够对异形面N形成保护，防止模切断面产生金属粉末或活性物质粉末，在装配或使用时落入电极组件100中发生短路，还可防止模切端面产生尖锐部位或毛刺，以免在装配或使用时刺破隔膜130发生短路。
下面将基于本申请的极片10给出电极组件100的实施例。首先以图4至图9所示的扁平式卷绕电极组件100为例进行说明，
在一些实施例中，电极组件100包括：极性相反的第一极片110和第二极片120，第一极片110和第二极片120中的至少一个采用上述实施例的极片10。例如，可以只在第一极片110的端面设置异形面N，也可只在第二极片120的端面设置异形面N，或者第一极片110和第二极片120的端面均设置异形面N，以达到最优的缓解应力集中的效果。
在第一实施例中，如图5所示，电极组件100为卷绕结构，沿卷绕结构的卷绕方向，第一极片110的第一始端E1和第一末端S1、第二极片120的第二始端E2和第二末端S2中的至少一个设有异形面N。若将第一方向x定义为极片10的长度方向，则第一端面101设有异形面N。
该实施例在卷绕式电极组件100中，若在第一极片110和/或第二极片120的末端设置异形面N，在电极组件100膨胀作用于壳体210后，壳体210会向电极组件100最外层的极片10施加反作用力，通过设置异形面N，可避免在第一末端S1或第二末端S2形 成较厚的台阶，缓解在壳体210挤压下产生应力集中问题，减少极片10的末端发生偏移或变形，还可改善极片10上活性物质由于受到挤压发生脱落的现象；此外，外层应力的减小可减少向内层传递的应力，从而缓解电极组件100的整体变形。若在第一极片110和/或第二极片120的始端设置异形面N，在壳体210施加于电极组件100的作用力向内层传递时，可减少始端发生偏移或变形，并减少极片10上的活性物质脱落，还可防止电极组件100的中心孔塌陷。
在一些实施例中，仍参考图5，异形面N为斜面，第一末端S1和第二末端S2中至少一个的异形面N与其沿卷绕结构径向的内侧面形成锐角；和/或第一始端E1和第二始端E2中至少一个的异形面N与其沿卷绕结构径向的外侧面形成锐角。
该实施例中，对于位于电极组件100最外层的第一极片120的第一末端S1或第二极片120的第二末端S2，异形面N与其沿卷绕结构径向的内侧面形成锐角，便于使位于电极组件100最外侧的绝缘膜130包覆锐角形成的斜坡结构，在减小极片10端部台阶厚度的同时，可使第一末端S1或第二末端S2与内层极片10自然贴合，无需向第一末端S1或第二末端S2施加外力使其与内层极片10贴合，可减小第一末端S1或第二末端S2的变形，并防止由于极片10末端朝内压合造成隔膜130损伤，提高电极组件100在工作时的可靠性和安全性。
对于第一始端E1和第二始端E2，若异形面N与其沿卷绕结构径向的外侧面形成锐角，可增大第一始端E1或第二始端E2与相邻外层极片10的接触面积，增加相邻外层极片10对第一始端E1或第二始端E2的支撑力，使始端不容易翘起，减少发生端部发生偏移或变形的可能性，提高电极组件100在工作时的可靠性和安全性。
在一些实施例中，如图6所示，第一极片110为负极片，第二极片120为正极片，在与第二方向y一致的卷绕轴线K上，第一极片110的第二端面102超出第二极片120的第二端面102，第一极片110的第二端面102具有异形面N。
该实施例中，由于在电极组件100沿卷绕方向K的端部，负极片的宽度超出正极片，正极片夹在相邻负极片之间，第一极片110的第二端面102具有异形面N，可改善正极片在第二端面102所在区域出现应力集中的问题，防止正极片的第二端面102由于受到相邻负极片的挤压而发生变形，并改善极片10上活性物质由于受到挤压发生脱落的现象，从而提高电极组件100在使用过程中的性能。
在另一些实施例中，如图15所示，为圆柱形电极组件100，图16为图15的D处放大图，第二极片120的第二始端E2设有异形面N，异形面N为斜面，以卷绕中心与异形面N最外端连线作为参考平面P，斜面与参考平面P之间形成夹角θ1，第一极片120 的第一始端E1未设置异形面N。图17为图15的E处放大图，第一极片110的第一末端S1和第二极片120的第二末端S2均设有异形面N，该异形面N为斜面，以卷绕中心与异形面N最外端连线作为参考平面P，第一末端S1的异形面N与参考平面P之间形成夹角θ2，第二末端S2的异形面N与参考平面P之间形成夹角θ3。
其次，本申请提供了一种电极组件100的制造方法，如图15所示，在一些实施例中，该制造方法包括：
S110、极片提供步骤：提供极性相反的第一极片110和第二极片120，第一极片110和第二极片120中的至少一个为如下结构极片10：极片10沿第一方向x具有第一端面101，沿第二方向y具有第二端面102，第二方向y垂直于第一方向x，第一端面101和第二端面102中的至少一个具有异形面N，异形面N沿第三方向z的部分区域偏离参考平面P，参考平面P被构造为垂直于第一方向x，且通过异形面N沿第一方向x位于最外侧的边缘，第三方向z垂直于第一方向x和第二方向y；例如，异形面N可通过采用刀具裁切的方式形成。
S120、电极成形步骤：将第一极片110和第二极片120形成电极组件100。例如，可采用卷绕或叠片的方式形成电极组件100。
该实施例的制造方法将极片10的第一端面101和第二端面102中的至少一个设置为异形面N，在极片10通过卷绕形成多层层叠的卷绕式电极组件100，或者多个极片10沿第三方向z叠加形成叠片式电极组件100时，通过减小极片10端部的厚度，可改善在受到壳体210施加于电极组件100的反作用力时的应力集中问题，防止极片10端部发生位置偏移或变形，并防止电极组件100发生变形，从而改善极片10上活性物质由于受到挤压发生脱落的现象。因此，此种改进能够保证电池单体200在长期使用后的性能。
最后，本申请提供了一种电极组件100的制造装置500，如图16所示，制造装置500包括：极片提供设备510和极片成形设备520。
其中，极片提供设备510被配置为提供极性相反的第一极片110和第二极片120，第一极片110和第二极片120中的至少一个为如下结构极片10：极片10沿第一方向x具有第一端面101，沿第二方向y具有第二端面102，第二方向y垂直于第一方向x，第一端面101和第二端面102中的至少一个具有异形面N，异形面N沿第三方向z的部分区域偏离参考平面P，参考平面P被构造为垂直于第一方向x，且通过异形面N沿第一方向x位于最外侧的边缘，第三方向z垂直于第一方向x和第二方向y。
极片成形设备520被配置为将第一极片110和第二极片120形成电极组件100。
虽然已经参考优选实施例对本申请进行了描述，但在不脱离本申请的范围的情况 下，可以对其进行各种改进并且可以用等效物替换其中的部件。尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本申请并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。

Claims (17)

  1. 一种极片(10)，沿第一方向(x)具有第一端面(101)，沿第二方向(y)具有第二端面(102)，所述第二方向(y)垂直于所述第一方向(x)；
    所述第一端面(101)和所述第二端面(102)中的至少一个具有异形面(N)，所述异形面(N)沿第三方向(z)的部分区域偏离参考平面(P)，所述参考平面(P)被构造为垂直于所述第一方向(x)，且通过所述异形面(N)沿所述第一方向(x)位于最外侧的边缘，所述第三方向(z)垂直于所述第一方向(x)和所述第二方向(y)。
  2. 根据权利要求1所述的极片(10)，其中，所述异形面(N)为平面，且与所述参考平面(P)之间形成预设角度(θ)，所述预设角度(θ)不等于90°。
  3. 根据权利要求1所述的极片(10)，其中，所述异形面(N)沿所述第三方向(z)弯曲延伸。
  4. 根据权利要求3所述的极片(10)，其中，所述异形面(N)为沿所述第三方向(z)的中间区域向外凸出的弧面。
  5. 根据权利要求1至4任一项所述的极片(10)，其中，所述异形面(N)与所述极片(10)的侧面之间邻接的边缘设有过渡角(13)，所述极片(10)的侧面垂直于所述第三方向(z)。
  6. 根据权利要求1至5任一项所述的极片(10)，包括：
    集流体(11)；和
    涂覆层(12)，沿所述第三方向(z)设置于所述集流体(11)的侧面；
    其中，所述异形面(N)包括第一分段面(N1)和第二分段面(N2)，所述第一分段面(N1)位于所述集流体(11)上，所述第二分段面(N2)位于所述涂覆层(12)上，所述第二分段面(N2)沿所述第一方向(x)相对于所述第一分段面(N1)向内缩回预设距离。
  7. 根据权利要求1至6任一项所述的极片(10)，包括：
    集流体(11)；和
    涂覆层(12)，沿所述第三方向(z)设置于所述集流体(11)的侧面；
    所述集流体(11)包括主体部(111)和极耳部(112)，所述极耳部(112)从所述主体部(111)沿所述第二方向(y)的端面向外凸出，所述异形面(N)设置于所述第二端面(102)除去所述极耳部(112)未设置所述涂覆层(12)的区域。
  8. 根据权利要求7所述的极片(10)，其中，所述极片(10)为正极片，所述涂覆层 (12)包括沿所述第二方向(y)并排设置的活性物质层(121)和绝缘层(122)，所述绝缘层(122)沿所述第二方向(y)位于所述活性物质层(121)靠近所述极耳部(112)的一侧，所述异形面(N)上包裹有所述绝缘层(122)熔融后产生的聚合物。
  9. 一种电极组件(100)，包括：极性相反的第一极片(110)和第二极片(120)，所述第一极片(110)和所述第二极片(120)中的至少一个采用权利要求1～8任一项所述的极片(10)。
  10. 根据权利要求9所述的电极组件(100)，其中，所述电极组件(100)为卷绕结构，沿所述卷绕结构的卷绕方向，所述第一极片(110)的第一始端(E1)和第一末端(S1)、所述第二极片(120)的第二始端(E2)和第二末端(S2)中的至少一个设有所述异形面(N)。
  11. 根据权利要求10所述的电极组件(100)，其中，所述异形面(N)为斜面，所述第一末端(S1)和所述第二末端(S2)中至少一个的异形面(N)与其沿所述卷绕结构径向的内侧面形成锐角；和/或所述第一始端(E1)和所述第二始端(E2)中至少一个的异形面(N)与其沿所述卷绕结构径向的外侧面形成锐角。
  12. 根据权利要求10或11所述的电极组件(100)，其中，第一极片(110)为负极片，所述第二极片(120)为正极片，在与所述第二方向(y)一致的卷绕轴线(K)上，所述第一极片(110)的第二端面(102)超出所述第二极片(120)的第二端面(102)，所述第一极片(110)的所述第二端面(102)具有所述异形面(N)。
  13. 一种电池单体(200)，包括：
    壳体(210)，具有开口；
    权利要求9～12任一项所述的电极组件(100)，设在所述壳体(210)内；和
    端盖组件(220)，用于封闭所述开口。
  14. 一种电池(300)，包括：箱体(301)和权利要求13所述的电池单体(200)，所述电池单体(200)设在所述箱体(301)内。
  15. 一种用电装置(400)，包括权利要求14所述的电池(300)，所述电池(300)用于为所述用电装置(400)提供电能。
  16. 一种电极组件(100)的制造方法，包括：
    极片提供步骤：提供极性相反的第一极片(110)和第二极片(120)，所述第一极片(110)和所述第二极片(120)中的至少一个为如下结构极片(10)：所述极片(10)沿第一方向(x)具有第一端面(101)，沿第二方向(y)具有第二端面(102)，所述第二方向(y)垂直于所述第一方向(x)，所述第一端面(101)和所述第二端面(102) 中的至少一个具有异形面(N)，所述异形面(N)沿第三方向(z)的部分区域偏离参考平面(P)，所述参考平面(P)被构造为垂直于所述第一方向(x)，且通过所述异形面(N)沿所述第一方向(x)位于最外侧的边缘，所述第三方向(z)垂直于所述第一方向(x)和所述第二方向(y)；
    电极成形步骤：将所述第一极片(110)和所述第二极片(120)形成所述电极组件(100)。
  17. 一种电极组件(100)的制造装置(500)，包括：
    极片提供设备(510)，被配置为提供极性相反的第一极片(110)和第二极片(120)，所述第一极片(110)和所述第二极片(120)中的至少一个为如下结构极片(10)：所述极片(10)沿第一方向(x)具有第一端面(101)，沿第二方向(y)具有第二端面(102)，所述第二方向(y)垂直于所述第一方向(x)，所述第一端面(101)和所述第二端面(102)中的至少一个具有异形面(N)，所述异形面(N)沿第三方向(z)的部分区域偏离参考平面(P)，所述参考平面(P)被构造为垂直于所述第一方向(x)，且通过所述异形面(N)沿所述第一方向(x)位于最外侧的边缘，所述第三方向(z)垂直于所述第一方向(x)和所述第二方向(y)；和
    极片成形设备(520)，被配置为将所述第一极片(110)和所述第二极片(120)形成所述电极组件(100)。
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