WO2023020127A1 - 电极组件、电池单体、电池及用电设备 - Google Patents

电极组件、电池单体、电池及用电设备 Download PDF

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Publication number
WO2023020127A1
WO2023020127A1 PCT/CN2022/102462 CN2022102462W WO2023020127A1 WO 2023020127 A1 WO2023020127 A1 WO 2023020127A1 CN 2022102462 W CN2022102462 W CN 2022102462W WO 2023020127 A1 WO2023020127 A1 WO 2023020127A1
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WIPO (PCT)
Prior art keywords
pole piece
electrode assembly
insulating layer
battery
present application
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PCT/CN2022/102462
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English (en)
French (fr)
Inventor
王曦童
唐代春
杜鑫鑫
喻鸿钢
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 EP22857440.6A priority Critical patent/EP4246651A1/en
Publication of WO2023020127A1 publication Critical patent/WO2023020127A1/zh
Priority to US18/357,408 priority patent/US20230369636A1/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
    • 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
    • H01M10/0409—Machines for assembling batteries for cells with wound electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H01M10/0431—Cells with wound or folded electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/103—Primary casings; Jackets or wrappings characterised by their shape or physical structure prismatic or rectangular
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/30—Arrangements for facilitating escape of gases
    • H01M50/383—Flame arresting or ignition-preventing means
    • 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, in particular, to an electrode assembly, a battery cell, a battery and an electrical device.
  • Batteries are widely used in the field of new energy, such as electric vehicles, new energy vehicles, etc. New energy vehicles and electric vehicles have become a new trend in the development of the automotive industry. The safety and life of batteries are very important for electrical equipment, so how to improve the safety and cycle life of batteries is an important research direction in the field of battery technology.
  • the present application aims to provide an electrode assembly, a battery cell, a battery and electrical equipment, so as to improve the safety and cycle life of the battery.
  • an electrode assembly which includes:
  • the first pole piece, the second pole piece and the first insulating layer, the first pole piece and the second pole piece are wound to form the electrode assembly, and the winding end of the first pole piece exceeds the
  • the winding end of the second pole piece is at least half a circle, so that the first pole piece completely covers the outer surface of the second pole piece in the outermost circle, and the first insulating layer is coated on the outermost circle. the outer surface of the first pole piece.
  • the outermost layer of the electrode assembly provided by this application is the first pole piece.
  • the sheet is exposed to prevent lithium deposition, improve the cycle life of the battery, and prevent the first pole piece and the exposed second pole piece from simultaneously contacting the battery case to cause a short circuit, thereby improving the safety of the battery; and the first pole piece on the outermost circle
  • a first insulating layer is provided on the surface of the sheet to prevent the first pole piece from contacting the battery casing, thereby further avoiding safety risks and short-circuit risks caused by electrification of the battery casing, and improving battery safety.
  • the first insulating layer extends at least half a turn from the winding end of the first pole piece.
  • the first insulating layer surrounds at least half a circle of the outermost layer of the electrode assembly (i.e. the outer circumference of the electrode assembly), and the two electrode assemblies can be combined so that the parts of the two electrode assemblies that are not provided with an insulating layer are attached to each other. Then the first insulating layers of the two electrode assemblies form an insulating closed loop together.
  • the insulation and isolation between the electrode assembly and the battery casing can be ensured, thereby improving the safety of the battery.
  • the electrode assembly has a straight zone, a first bent zone and a second bent zone, and the straight zone is located between the first bent zone and the second bent zone. Between the bending areas, the winding ending end of the first pole piece is located in the first bending area.
  • the flat area of the electrode assembly is where the large surface is located.
  • the large surface of the electrode assembly is mainly swollen, and the large surface is easy to contact the casing.
  • the large surface is completely covered with an insulating layer, which can effectively prevent the large surface from overlapping the casing. Risk of short circuit.
  • the first bending region has a first vertex farthest from the winding center of the electrode assembly, and the second bending region has a winding center farthest from the electrode assembly.
  • the second apex farthest from the center, the first insulating layer covers the first apex and the second apex.
  • the first insulating layer not only surrounds the electrode assembly at least half a circle, but also covers the first apex and the second apex, which makes the first insulating layer not only insulate and isolate the large surface of the electrode assembly and the battery casing, but also Insulate and isolate the two ends of the electrode assembly and the battery casing, ensuring that the parts where the electrode assembly and the battery casing are likely to be in contact have a first insulating layer.
  • the first insulating layer extends at least one turn from the winding end of the first pole piece.
  • the first insulating layer surrounds the outer circumference of the electrode assembly at least once, ensuring that the outer circumference of the electrode assembly is fully covered by the first insulating layer to ensure the insulation effect.
  • the first insulating layer is only coated on the part of the first pole piece beyond the winding end of the second pole piece.
  • the first insulating layer is only coated on the part of the first pole piece beyond the winding end of the second pole piece, so as to prevent the first insulating layer from interfering with the transfer of lithium ions and preventing lithium precipitation.
  • the inner surface of the part of the first pole piece beyond the winding end of the second pole piece is coated with a second insulating layer.
  • the inner or outer surface of the part of the first pole piece beyond the winding end of the second pole piece is coated with a flame retardant layer and/or an air getter layer.
  • the part of the first pole piece beyond the second pole piece can also be coated with other materials, so as to be flame-retardant or gas-absorbing, and further improve safety.
  • the electrode assembly further includes a diaphragm, the diaphragm is arranged between the first pole piece and the second pole piece, and the wound end of the diaphragm exceeds the The winding end of the first pole piece is at least 1.75 turns.
  • the diaphragm further wraps the first pole piece and the second pole piece on the outside of the electrode assembly to increase the binding force, so that the winding end of the first pole piece can be better attached to the second pole piece of the secondary outer ring.
  • it effectively alleviates the problem that the gap between the first pole piece and the second pole piece increases due to the looseness of the winding end of the first pole piece and the winding end of the second pole piece, thereby preventing the gap from increasing Lead to lithium precipitation phenomenon, effectively improve safety.
  • an embodiment of the present application provides a battery cell, which includes a casing and at least one electrode assembly as described above, and the electrode assembly is disposed in the casing.
  • an embodiment of the present application provides a battery, which includes the aforementioned battery cell.
  • the embodiment of the present application provides an electric device, which includes the aforementioned battery.
  • Fig. 1 is a schematic structural diagram of a vehicle provided by an embodiment of the present application.
  • Fig. 2 is an exploded schematic diagram of a battery provided by an embodiment of the present application.
  • Fig. 3 is an exploded schematic diagram of a battery cell provided by an embodiment of the present application.
  • Fig. 4 is a planar winding schematic diagram of an electrode assembly provided by an embodiment of the present application.
  • Fig. 5 is a planar winding schematic diagram of an electrode assembly provided by another embodiment of the present application.
  • Fig. 6 is a schematic structural diagram of a combination of two electrode assemblies provided by an embodiment of the present application.
  • Fig. 7 is a schematic structural diagram of a combination of three electrode assemblies provided by an embodiment of the present application.
  • Fig. 8 is a schematic structural diagram of a combination of three electrode assemblies provided by another embodiment of the present application.
  • Fig. 9 is a planar winding schematic diagram of an electrode assembly provided by another embodiment of the present application.
  • Fig. 10 is a planar winding schematic diagram of a square electrode assembly provided by an embodiment of the present application.
  • Fig. 11 is a planar winding schematic diagram of a square electrode assembly provided by another embodiment of the present application.
  • Fig. 12 is a schematic structural diagram of a combination of two electrode assemblies provided by another embodiment of the present application.
  • Fig. 13 is a planar winding schematic diagram of a square electrode assembly provided by another embodiment of the present application.
  • Fig. 14 is a schematic structural view of a square electrode assembly provided by an embodiment of the present application when the first insulating layer is circled;
  • Fig. 15 is a schematic structural view of a cylindrical electrode assembly provided by an embodiment of the present application when the first insulating layer surrounds it;
  • FIG. 16 is a schematic structural diagram of a second insulating layer provided by an embodiment of the present application.
  • Fig. 17 is a schematic perspective view of a combination of two square electrode assemblies provided by an embodiment of the present application.
  • Marking instructions 100-battery; 101-box; 1011-first part; 1012-second part; 1-battery unit; 11-shell; 111-opening; 12-electrode assembly; 12c-second bending area; 121-first pole piece; 1211-first pole piece; 122-second pole piece; 1221-second pole piece; 123-first insulating layer; 124 125-diaphragm; 13-end cover assembly; 131-cover plate; 132-first electrode terminal; 133-second electrode terminal; 200-motor; 300-controller; 1000-vehicle.
  • multiple refers to more than two (including two), similarly, “multiple groups” refers to more than two groups (including two), and “multiple pieces” refers to More than two pieces (including two pieces).
  • the battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, which are not limited in the embodiments of the present application.
  • the battery cell can be in the form of a cylinder, a flat body, a cuboid or other shapes, which is not limited in this embodiment of the present application.
  • Battery cells are generally divided into three types according to packaging methods: cylindrical battery cells, square battery cells and pouch battery cells, which are not limited in this embodiment of the present application.
  • the battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.
  • the battery mentioned in this application may include a battery module or a battery pack, and the like.
  • Batteries generally include a case for enclosing one or more battery cells. The box can prevent liquid or other foreign objects from affecting the charging or discharging of the battery cells.
  • the battery cell includes an electrode assembly and an electrolyte, and the electrode assembly is composed of a positive pole piece, a negative pole piece and a diaphragm.
  • a battery cell works primarily by moving metal ions between the positive and negative pole pieces.
  • 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 not coated with 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 is used as the positive electrode tab.
  • the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium or lithium manganate.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, the negative electrode active material layer is coated on the surface of the negative electrode current collector, and the current collector not coated with the negative electrode active material layer protrudes from the current collector coated with the negative electrode active material layer, The current collector not coated with the negative electrode active material layer is used as the negative electrode tab.
  • the material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon or silicon.
  • the number of positive pole tabs is multiple and stacked together, and the number of negative pole tabs is multiple and stacked together.
  • the material of the diaphragm can be PP (polypropylene, polypropylene) or PE (polyethylene, polyethylene), etc.
  • the diaphragm has electronic insulation and is used to isolate adjacent positive and negative pole pieces to prevent short circuit between adjacent positive and negative pole pieces.
  • the separator has a large number of penetrating micropores, which can ensure the free passage of electrolyte ions and have good permeability to lithium ions. Therefore, the separator basically cannot block the passage of lithium ions.
  • the battery cell also includes a casing with an opening and a cover plate for closing the opening, and the casing is used for accommodating the electrode assembly.
  • the development of battery technology should consider many design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters.
  • the safety of the battery also needs to be considered.
  • the insulation between the electrode assembly and the shell of the battery cell is one of the important factors affecting the safety performance of the battery. If the shell of the battery cell contacts the electrode assembly and is charged, there is a greater risk of short circuit, causing a safety hazard.
  • a polyester film (mylar film) is generally provided on the outside of the electrode assembly to isolate the electrode assembly and the casing to achieve the purpose of insulation.
  • mylar film is installed, sometimes there is still insulation failure, and sometimes there is lithium precipitation.
  • the inventors have found that the electrode assembly will expand and contract during charging and discharging. When the electrode assembly expands, the mylar membrane will expand, but when it shrinks, the mylar membrane will not shrink together with the electrode assembly, which leads to the gap between the electrode assembly and the mylar membrane.
  • the gap increases, and the granular impurities in the battery cell (such as welding slag generated during the welding process of the battery cell and the cover plate, metal particles generated by rework files, etc.) easily enter the enlarged gap.
  • these granular impurities will act on the pole piece and the mylar film, causing the pole piece and the mylar film to be deformed and damaged due to excessive local stress, and the damage of the mylar film will easily lead to insulation failure, resulting in safety hazards.
  • lithium ions are deintercalated from the positive pole piece and intercalated into the negative pole piece.
  • the resistance of intercalating the negative pole piece is too large or the lithium ions are deintercalated from the positive pole piece too quickly.
  • the deintercalated lithium ions cannot be embedded in the negative active material layer of the negative pole piece in equal amounts, and the lithium ions that cannot be embedded in the negative pole piece can only be in the negative pole piece. Electrons are obtained on the surface of the negative electrode sheet, thereby forming a silver-white metal lithium element, which is the phenomenon of lithium precipitation.
  • the deformation of the pole piece will cause the distance between the negative pole piece and the positive pole piece to be too large, so the deformation of the pole piece will easily lead to lithium precipitation.
  • Lithium analysis not only reduces the performance of lithium-ion battery cells, greatly shortens the cycle life, but also limits the fast charging capacity of lithium-ion battery cells.
  • the precipitated lithium metal is very active, and can react with the electrolyte at a lower temperature, resulting in a decrease in the initial temperature of the self-heating of the battery cell and a decrease in the self-heating The speed increases, seriously endangering the safety of the battery cell.
  • the deintercalated lithium ions can form lithium crystals on the surface of the negative electrode sheet, and the lithium crystals are easy to pierce the separator, causing the adjacent positive electrode sheet and negative electrode sheet to have a short circuit risk.
  • the inventors of the present application provide a solution to solve the problem of insulation failure and lithium deposition, in which the winding end of the first pole piece exceeds the winding end of the second pole piece by at least half a circle, so as to The first pole piece completely covers the outer surface of the outermost second pole piece, and the first insulating layer is coated on the outer surface of the outermost first pole piece.
  • the first insulating layer By arranging the first insulating layer on the outer surface of the outermost pole piece of the electrode assembly, the first insulating layer shields the part of the electrode assembly that is easy to contact with the casing, so as to prevent this part from contacting the casing and alleviate the risk of live short circuit of the casing, thereby improving safety.
  • the winding end of the first pole piece of the electrode assembly exceeds the winding end of the second pole piece by at least half a circle, so as to completely cover and wrap the second pole piece tightly with the first pole piece, preventing the first pole piece from The winding end and the winding end of the second pole piece are loose, so as to avoid the problem that the winding end of the second pole piece is exposed, so as to avoid the short circuit of the first pole piece and the exposed second pole piece contacting the battery case at the same time , thereby further improving security. And avoid lithium precipitation due to the partial exposure of the second pole piece, resulting in insufficient intercalation space.
  • Utilizing the first pole piece to wrap the second pole piece tightly can also alleviate the problem that the gap between the winding end of the second pole piece and the first pole piece increases due to looseness, so as to avoid the gap between the negative pole piece and the positive pole piece. If the distance is too large, lithium is separated; it also prevents particulate matter from entering between the first pole piece and the second pole piece, avoiding particle damage to the pole piece and diaphragm when the pole piece expands next time, and further preventing damage from causing lithium precipitation and short circuit problems.
  • the battery cells disclosed in the embodiments of the present application can be used, but not limited to, in electric devices such as vehicles, ships or aircrafts.
  • the power supply system comprising the battery unit and battery disclosed in this application can be used to form the electrical device, which is conducive to alleviating and automatically adjusting the deterioration of the expansion force of the battery cell, supplementing the consumption of the electrolyte, and improving the stability of battery performance and battery life. .
  • the embodiment of the present application provides an electric device using a battery as a power source.
  • the electric device can be, but not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, and the like.
  • electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric boat toys, electric airplane toys, etc.
  • spacecraft can include airplanes, rockets, space shuttles, spaceships, etc.
  • a vehicle 1000 in an embodiment of the present application the vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle wait.
  • a battery 100 , a controller 300 and a motor 200 may be provided inside the vehicle 1000 , and the controller 300 is used to control the battery 100 to supply power to the motor 200 .
  • the battery 100 may be provided at the bottom or front or rear of the vehicle 1000 .
  • the battery 100 can be used for power supply of the vehicle 1000 , for example, the battery 100 can be used as an operating power source of the vehicle 1000 , for a circuit system of the vehicle 1000 , for example, for starting, navigating, and working power requirements of the vehicle 1000 .
  • the battery 100 can not only be used as an operating power source for the vehicle 1000 , but can also be used as a driving power source for the vehicle 1000 , replacing or partially replacing fuel oil or natural gas to provide driving power for the vehicle 1000 .
  • the battery 100 may include multiple battery cells, wherein the multiple battery cells may be connected in series, in parallel or in parallel, and the hybrid connection refers to a mixture of series and parallel connections.
  • the battery 100 may also be called a battery pack.
  • multiple battery cells 1 can be connected in series, parallel or mixed to form a battery module, and then multiple battery modules can be connected in series, parallel or mixed to form a battery 100 . That is to say, a plurality of battery cells 1 can directly form the battery 100 , or can first form a battery module, and then the battery module can form the battery 100 .
  • the battery 100 may include a plurality of battery cells 1 .
  • the battery 100 may further include a box body 101 (or called a cover body), the interior of the box body 101 is a hollow structure, and a plurality of battery cells 1 are accommodated in the box body 101 .
  • the box body 101 may include two parts for accommodating (refer to FIG. 2 ), referred to here as a first part 1011 and a second part 1012 respectively, and the first part 1011 and the second part 1012 are fastened together.
  • the shapes of the first part 1011 and the second part 1012 may be determined according to the combined shape of a plurality of battery cells 1 , and each of the first part 1011 and the second part 1012 may have an opening.
  • both the first part 1011 and the second part 1012 can be hollow cuboids and each has only one face as an open face, the opening of the first part 1011 and the opening of the second part 1012 are arranged oppositely, and the first part 1011 and the second part 1012 are interlocked Combined to form a box 101 with a closed chamber.
  • the first part 1011 and the second part 1012 one may also be a cuboid with an opening, and the other may be a cover structure to close the opening of the cuboid.
  • a plurality of battery cells 1 are combined in parallel, in series or in parallel and placed in the box 101 formed by fastening the first part 1011 and the second part 1012 .
  • the battery 100 may also include other structures.
  • the battery 100 may also include a confluence part, which is used to realize the electrical connection between a plurality of battery cells 1 , such as parallel connection, series connection or mixed connection.
  • the current-combining component can realize the electrical connection between the battery cells 1 by connecting the electrode terminals of the battery cells 1 .
  • the bus member may be fixed to the electrode terminal of the battery cell 1 by welding. The electric energy of the plurality of battery cells 1 can be further drawn out through the case body 101 through the conductive mechanism.
  • the conduction means can also belong to the current-collecting part.
  • FIG. 3 shows a battery cell 1 according to an embodiment of the present application.
  • the battery cell 1 includes a casing 11 , an end cap assembly 13 , an electrode assembly 12 and other functional components.
  • the shell 11 depends on the shape of the electrode assembly 12, for example, the shell 11 can be a hollow cuboid or cube or cylinder, and one of the faces of the shell 11 has an opening 111 so that one or more electrode assemblies 12 can be placed in the shell 11 .
  • the housing 11 is a hollow cuboid or cube
  • one of the planes of the housing 11 is a plane with an opening 111
  • the plane is configured without walls so that the inside and outside of the housing 11 communicate.
  • the electrode assembly 12 is a part where the electrochemical reaction occurs in the battery cell 1 .
  • One or more electrode assemblies 12 may be contained within the housing 11 .
  • the electrode assembly 12 is mainly formed by winding or laminating a positive pole piece and a negative pole piece, and a separator 125 is usually provided between the positive pole piece and the negative pole piece.
  • the part of the positive pole piece and the negative pole piece with the active material constitutes the main body of the electrode assembly 12 , and the parts of the positive pole piece and the negative pole piece without the active material respectively form tabs.
  • the positive pole tab and the negative pole tab can be located at one end of the main body together or at two ends of the main body respectively.
  • the positive electrode active material and the negative electrode active material react with the electrolyte.
  • the number of electrode terminals is two, and the number of adapter pieces is also two.
  • the positive pole lug is connected to one electrode terminal through one adapter piece, and the negative pole lug is connected to the other electrode terminal through another adapter piece.
  • the end cover assembly 13 is used to cover the opening 111 and is connected with the casing 11 to form a closed cavity for placing the electrode assembly 12, which is isolated from the external environment and used to accommodate the electrode assembly 12 and electrolyte (such as electrolyte) wait.
  • the end cap assembly 13 includes a cover plate 131 for closing the opening 111 and connecting with the housing 11 .
  • the end cover assembly 13 further includes a first electrode terminal 132 and a second electrode terminal 133 , and the first electrode terminal 132 and the second electrode terminal 133 can be disposed on the cover plate 131 .
  • the cover plate 131 is generally in the shape of a flat plate.
  • the first electrode terminal 132 and the second electrode terminal 133 are fixed on the plate surface of the cover plate 131 .
  • the first electrode terminal 132 and the second electrode terminal 133 are used for electrical connection with the electrode assembly 12 .
  • the electrode assembly 12 provided by the present application can be cylindrical, flat or other shapes, please refer to FIG. 4, which shows a cylindrical electrode assembly according to an embodiment of the present application 12 is a schematic plan view of the winding structure.
  • the electrode assembly 12 includes a first pole piece 121, a second pole piece 122 and a first insulating layer 123.
  • the first pole piece 121 and the second pole piece 122 are wound to form the electrode assembly 12.
  • the winding end of a pole piece 121 exceeds the winding end of the second pole piece 122 by at least half a circle, so that the first pole piece 121 completely covers the outer surface of the outermost second pole piece 122, and the first insulating layer 123 is coated on the outer surface of the outermost first pole piece 121 .
  • the first pole piece 121 and the second pole piece 122 have opposite polarities.
  • the first pole piece 121 may be a negative pole piece
  • the second pole piece 122 may be a positive pole piece.
  • the first pole piece 121 and the second pole piece 122 are laminated and wound into shape, wherein the first pole piece 121 is provided with a first pole piece 1211, and the second pole piece 122 is provided with a second pole piece 1221 (see FIG. 3 ),
  • the first tab 1211 is used to connect to the first electrode terminal 132
  • the second tab 1221 is used to connect to the second electrode terminal 133 .
  • One circle in this application means: starting from a certain point of the electrode assembly 12 , going one circle along the winding direction to another point, and the line connecting the other point and the starting point is along the radial direction of the electrode assembly 12 .
  • half a circle refers to half of one circle
  • 0.75 circles refers to 0.75 of one circle.
  • the winding end of the first pole piece 121 exceeds the winding end of the second pole piece 122 by at least half a turn, that is, after the second pole piece 122 ends, the first pole piece 121 continues to wind until it completely covers the second pole 122, and after the first pole piece 121 completely covers the second pole piece 122, it still continues to wind for half a circle and then finishes.
  • the outermost layer of the electrode assembly 12 is the first pole piece 121
  • the first pole piece At the position where 121 exceeds the winding end of the second pole piece 122 , the outermost layer and the second outer layer of the electrode assembly 12 are both the first pole piece 121 .
  • the first pole piece 121 can be used to tightly wrap the second pole piece 122 to prevent the winding end of the first pole piece 121 and the winding end of the second pole piece 122 from loosening, resulting in the second pole piece 122 being rolled.
  • the winding end of the extended first pole piece 121 is exposed to the outer surface of the electrode assembly 12, and the winding end of the extended first pole piece 121 can ensure that the second pole piece 122 is always within the coverage of the first pole piece 121, thereby ensuring that the electrode assembly 12 faces the casing 11
  • the outer circumference of each pole is the first pole piece 121, so as to prevent the first pole piece 121 and the exposed second pole piece 122 from simultaneously contacting the casing 11 of the battery 100 to cause a short circuit.
  • the second pole piece 122 is always within the coverage of the first pole piece 121, and avoids the problem of insufficient space for intercalation of lithium due to lack of corresponding first pole piece 121 in the exposed part of the second pole piece 122, and avoids lithium deposition.
  • the extension of the tail end of the first pole piece 121 also improves the binding force, alleviates the problem that the gap between the first pole piece 121 and the second pole piece 122 increases due to the looseness of the tail end of the first pole piece 121, and avoids lithium precipitation. Therefore, it is possible to avoid damage to the pole piece due to lithium deposition and cause a short circuit, thereby ensuring the cycle life and safety of the battery 100 .
  • the first insulating layer 123 is arranged on the outer periphery of the electrode assembly 12 that may be in contact with the casing 11, that is, the outer surface of the first pole piece 121 arranged on the outermost layer of the electrode assembly 12, and the first insulating layer 123 connects the electrode assembly 12
  • the parts that are easy to touch the casing 11 are shielded, so as to insulate and isolate the electrode assembly 12 and the casing 11 , improving the safety of the battery 100 .
  • the first insulating layer 123 extends at least half a circle from the winding end of the first pole piece 121 .
  • the winding ending end of the first pole piece 121 exceeds the winding ending end of the second pole piece 122 by half a circle, and the first insulating layer 123 is coated on the first pole piece 121 beyond the second pole piece 122.
  • the first insulating layer 123 extends half a circle from the winding end of the first pole piece 121 in a direction opposite to the winding direction of the pole piece.
  • the first insulating layer 123 can also extend along the winding direction of the pole piece, extending half a circle from the winding end of the first pole piece 121, as shown in FIG. 5 , which shows another A schematic plan view of the winding structure of the electrode assembly 12 of the embodiment, the first insulating layer 123 is located at the part of the first pole piece 121 that does not exceed the second pole piece 122 .
  • a part of the first insulating layer 123 may also be located at a portion of the first pole piece 121 that exceeds the second pole piece 122 , and another part is located at a portion of the first pole piece 121 that does not exceed the second pole piece 122 .
  • Figure 6 shows a combination of two electrode assemblies 12, the peripheral surfaces of the two electrode assemblies 12 that are not provided with the first insulating layer 123 are close to or in contact, so that the two electrode assemblies 12 are provided with the first insulating layer
  • the outer peripheral surface of 123 faces the inner wall of the casing 11, thereby ensuring that any part of the electrode assembly 12 facing the casing 11 is covered by the first insulating layer 123, and the combination of the two electrode assemblies 12 forms an insulating closed loop, which effectively prevents short circuits and improves safety.
  • three or more electrode assemblies 12 may also be combined and then assembled into the casing 11 .
  • Fig. 7 shows a kind of combination of three electrode assemblies 12, as shown in Fig. 7, three electrode assemblies 12 are placed in a triangle, and the surface of the first pole piece 121 of the outermost layer of each electrode assembly 12 is provided with A half circle of the first insulating layer 123, the outer peripheral surfaces of each electrode assembly 12 not provided with the first insulating layer 123 are opposite, so that the outer peripheral surfaces of the two electrode assemblies 12 provided with the first insulating layer 123 face the inner wall of the casing 11, thereby Form an insulating closed loop.
  • Fig. 8 shows another kind of combination of three electrode assemblies 12, as shown in Fig. 8, three electrode assemblies 12 are arranged successively, and the surface of the first pole piece 121 of the outermost layer of the electrode assembly 12 that is positioned at two ends is provided with A half-circle of the first insulating layer 123, the first insulating layer 123 is provided at the vertices of both ends of the electrode assembly 12 perpendicular to the arrangement direction in the middle.
  • FIG. 9 shows the winding structure of the electrode assembly 12 in the middle.
  • the outer peripheral surface of each electrode assembly 12 without the first insulating layer 123 faces the adjacent electrode assembly 12, while the outer peripheral surface provided with the first insulating layer 123 faces the outer casing 11, thereby forming an insulating closed loop.
  • the electrode assembly 12 has a straight region 12a, a first bending region 12b and a second bending region 12c, and the straight region 12a is located between the first bending region 12b and the second bending region 12c Between, the winding ending end of the first pole piece 121 is located in the first bending area 12b, and the first insulating layer 123 extends at least half a turn from the winding ending end of the first pole piece 121 .
  • the electrode assembly 12 is flat.
  • the electrode assembly 12 can be directly wound into a flat shape; it can also be wound into a circular or elliptical shape, and then the middle part of the electrode assembly 12 is compacted and compacted so that the middle part of the electrode assembly 12 forms a flat area 12a ,
  • the two ends of the straight zone 12a are bending zones (namely, the first bending zone 12b and the second bending zone 12c).
  • the straight zone 12a has two opposite surfaces, and the first bending zone 12b and the second bending zone 12c each have an arc-shaped surface. Relatively speaking, any surface of the straight zone 12a is larger than the first bending zone 12b or the curved surface of the second bending zone 12c, any surface of the straight zone 12a is often referred to as a large surface.
  • the winding ending end of the first pole piece 121 is located in the first bending area 12b, and the first insulating layer 123 extends at least half a circle from the winding ending end of the first pole piece 121, and the extension direction of the first insulating layer 123 can be along the
  • the winding direction of the electrode assembly 12 may also be opposite to the winding direction of the electrode assembly 12 .
  • the first insulating layer 123 extends half a circle from the winding end of the first pole piece 121 along the direction opposite to the winding direction of the pole piece, and the first insulating layer 123 is coated on the first pole piece. The portion of the piece 121 beyond the second pole piece 122 .
  • the first insulating layer 123 extends along the winding direction of the pole piece, extending half a circle from the winding end of the first pole piece 121, and the first insulating layer 123 is located at the first pole piece 121 not beyond the second part of pole piece 122 .
  • one side surface of the flat region 12 a of the electrode assembly 12 that is, a large surface on one side of the electrode assembly 12 and a portion adjacent to the large surface of the electrode assembly 12 have a first insulating layer 123 . Since there is generally a gap between the electrode assembly 12 and the casing 11, when the electrode assembly 12 expands during charge and discharge, the flat region 12a (that is, where the large surface is located) expands, so the flat region 12a is easy to contact the casing 11.
  • a large surface of one side of the component 12 is provided with a first insulating layer 123 , which can effectively prevent the risk of a short circuit caused by a large surface overlapping the casing 11 .
  • Figure 12 shows a combination of two electrode assemblies 12, the two electrode assemblies 12 are flat, and the outer peripheral surfaces of the two electrode assemblies 12 that are not provided with the first insulating layer 123 are close to or in contact, so that the two electrode assemblies 12
  • the outer peripheral surface of the electrode assembly 12 provided with the first insulating layer 123 faces the inner wall of the casing 11, that is to say, the large surfaces of the two electrode assemblies 12 not provided with the first insulating layer 123 are close to or in contact, and the first insulating layer 123 is provided.
  • the large surface on one side of the layer 123 faces the casing 11, thereby ensuring that any part of the electrode assembly 12 facing the casing 11 is covered by the first insulating layer 123, and the two electrode assemblies 12 are combined to form an insulating closed loop, which effectively prevents short circuits and improves safety.
  • the first bending region 12b has a first apex farthest from the winding center of the electrode assembly 12
  • the second bending region 12c has a second apex farthest from the winding center of the electrode assembly.
  • the first insulating layer 123 covers the first apex and the second apex.
  • the two vertices (first and second vertices) farthest from the winding center are located at both ends of the flat shape
  • the first apex and the second apex of the electrode assembly 12 may also contact the casing 11 .
  • the first insulating layer 123 By arranging the first insulating layer 123 , the first apex and the second apex are covered by the first insulating layer 123 , which effectively alleviates the problem that the first apex and the second apex contact the housing 11 and cause a short circuit.
  • the electrode assemblies 12 located at both ends of the arrangement direction are provided with a first insulating layer 123 on the large surface facing the casing 11, and the first insulating layer 123 Extending from the first apex to the second apex, as shown in Figure 10 or Figure 11; the electrode assembly 12 located in the middle of the arrangement direction is only provided with a first insulating layer 123 at the position of the first apex and the second apex, as shown in FIG. 13.
  • the parts of the combination of the three electrode assemblies 12 that may be in contact with the casing are covered by the first insulating layer 123 , so that an insulating closed loop is formed along the entire circumference of the combination of the three electrode assemblies 12 to prevent short circuits.
  • the first insulating layer 123 extends at least one turn from the winding end of the first pole piece 121 .
  • the first insulating layer 123 takes the winding end of the first pole piece 121 as a starting point and surrounds the outer circumference of the electrode assembly 12 to ensure that the outer circumference of the electrode assembly 12 is covered by the first insulating layer 123. Fully covered, a single electrode assembly 12 forms an insulating closed loop, thereby ensuring the effect of insulating and isolating the electrode assembly 12 and the casing 11 .
  • the first insulating layer 123 wraps around the outer circumference of the electrode assembly 12, it continues to extend for a certain length, so as to prevent the part without the first insulating layer 123 from exposing the outer circumference when the tail end of the first pole piece 121 is loosened. And contact the case 11 to cause a short circuit.
  • the first insulating layer 123 is only coated on the part of the first pole piece 121 beyond the winding end of the second pole piece 122 .
  • the part of the first pole piece 121 that does not exceed the winding end of the second pole piece 122 needs to receive lithium ions. part, in order to prevent the first insulating layer 123 from affecting the reception of lithium ions by the first pole piece 121, and prevent the problem of lithium precipitation.
  • the first pole piece 121 is at least half a circle beyond the winding end of the second pole piece 122 , and the first insulating layer 123 starts from the winding end of the first pole piece 121 in the opposite direction. It extends half a circle opposite to the winding direction of the pole piece.
  • the first insulating layer 123 may not start from the winding end of the first pole piece 121, but only from the part of the first pole piece 121 beyond the winding end of the second pole piece 122. Starting from other positions, and extending within the range of the portion of the first pole piece 121 beyond the winding end of the second pole piece 122 .
  • the first insulating layer 123 is provided at a partial position of the part of the first pole piece 121 beyond the winding end of the second pole piece 122 .
  • the inner surface of the part of the first pole piece 121 beyond the winding end of the second pole piece 122 is coated with the second insulating layer 124 .
  • the second insulating layer 124 will not affect the lithium intercalation space of the first pole piece 121, and will not cause lithium precipitation. The problem can also increase the thickness of the insulating layer to achieve a better insulating effect. Moreover, even if a sharp object pierces the shell 11 and pierces the part of the first pole piece 121 beyond the winding end of the second pole piece 122, the second insulating layer 124 can also isolate the second pole piece 122 of the second outer ring from the sharp object, The shell 11 further plays an insulating role.
  • the first pole piece 121 exceeds the winding end of the second pole piece 122 by at least one turn, and the first insulating layer 123 and the second insulating layer 124 are both arranged on the first pole piece. 121 exceeds the part of the winding end of the second pole piece 122, and the extension length of the first insulating layer 123 is at least one turn, and the extension length of the second insulating layer 124 is at least one turn, so that the outer periphery of the electrode assembly 12 forms double insulation. closed loop.
  • the first insulating layer 123 and the second insulating layer 124 in this application may be made of the same material, or may be made of different materials.
  • the materials constituting the first insulating layer 123 and the second insulating layer 124 may be: aluminum oxide, zirconium oxide, titanium dioxide, magnesium oxide, polymers, and polysemisiloxane modified with hydrophilic segments. one or more.
  • the material constituting the first insulating layer 123 and the second insulating layer 124 can also be an oily material, such as: one of liquid fluorine rubber, liquid silicone rubber, liquid polysulfide rubber, hydroxyl-terminated polybutadiene and toluene A mixture; or, a mixture comprising one of liquid fluororubber, liquid silicone rubber, liquid polysulfide rubber, and hydroxyl-terminated polybutadiene and a water solvent.
  • the above-mentioned mixture is coated on the surface of the first pole piece 121, which is usually a liquid colloid, so as to form a stable insulating layer on the surface of the first pole piece 121.
  • the oily material can also flow into the perforation or the groove, so that the inner wall of the perforation or the inner wall of the groove is covered by the oily material, and the oily material is cured by heat and then The new covering position forms an insulating layer to prevent the puncture hole from being exposed, and plays a role in preventing or delaying the short circuit time.
  • the inner or outer surface of the part of the first pole piece 121 beyond the winding end of the second pole piece 122 is coated with a flame retardant layer and/or a getter layer (not shown in the figure) .
  • the aforementioned second insulating layer 124 can be replaced by one of the flame retardant layer and the getter layer, or the second insulating layer 124 is replaced by a flame retardant layer stacked on the inner surface of the first pole piece 121 and the getter layer; or, at least one of the flame retardant layer and the getter layer is laminated and coated on the first insulating layer 123; or, the flame retardant layer and the getter layer are laminated and coated on the second insulating layer 124 at least one of .
  • the material of the flame-retardant layer includes one or more of aluminum hydroxide, pseudo-boehmite, boehmite, zirconium hydroxide, magnesium carbonate, basic magnesium carbonate, and calcium carbonate.
  • the material of the air-absorbing layer can be coenzyme Q10 (coenzyme Q10), that is, ubiquinone 10, which is a fat-soluble quinone ring compound.
  • coenzyme Q10 can transfer the oxidizing gas inside the electrode assembly 12, and reduce the by-product of the electrochemical reaction of the electrode assembly 12 to lithium oxide, thereby reducing the gas inside the battery, reducing the internal pressure, and improving safety.
  • the electrode assembly 12 further includes a diaphragm 125, and the diaphragm 125 is arranged between the first pole piece 121 and the second pole piece 122.
  • the winding end of a pole piece 121 is at least 1.75 turns.
  • the winding ending end of the separator 125 starts from the winding ending end of the first pole piece 121 , continues to extend and wind for one circle, and then continues winding for more than 0.75 turns and then ends and fixes.
  • the separator 125 between the first pole piece 121 and the second pole piece 122 can isolate the first pole piece 121 and the second pole piece 122 , so as to prevent the first pole piece 121 and the second pole piece 122 from contacting and short circuiting.
  • the length of the diaphragm 125 is greater than the length of the first pole piece 121, and the part of the diaphragm 125 beyond the winding end of the first pole piece 121 further wraps the first pole piece 121 and the second pole piece 122 to increase the binding force and prevent the first pole piece from
  • the winding end of the piece 121 is loose, and can better fix the winding end of the second pole piece 122, thereby preventing the gap between the first pole piece 121 and the second pole piece 122 from increasing at the end, so as to avoid the pole piece
  • the increase of the spacing leads to the problem of lithium precipitation, and further prevents the attached lithium crystals from piercing the diaphragm 125, causing a short circuit between the first pole piece 121
  • the present application also provides a battery cell 1 , which includes a casing 11 and at least one aforementioned electrode assembly 12 , and the electrode assembly 12 is disposed in the casing 11 .
  • the present application also provides a battery 100 , which includes the aforementioned battery cell 1 .
  • the present application further provides an electric device, which includes the aforementioned battery 100 .
  • the present application provides an electrode assembly 12, the electrode assembly 12 is formed by stacking the first pole piece 121, the second pole piece 122 and the separator 125 and then winding, the electrode After the assembly 12 is wound into a circle, the middle part is pressed to be compact and flat, so that the electrode assembly 12 includes a straight area 12a, a first bending area 12b and a second bending area 12c, wherein the straight area 12a is located at the second Between the first bending area 12b and the second bending area 12c.
  • the first pole piece 121 exceeds the winding end of the second pole piece 122 by at least half a circle, so that the first pole piece 121 completely covers the outer surface of the outermost winding of the second pole piece 122, and the outermost layer of the electrode assembly 12 (that is, the first pole piece 121 exceeds the half turn of the second pole piece 122's winding tail end) and the second outer layer (that is, the first pole piece 121 covers a circle of the outer surface of the second pole piece 122 of the outermost circle) It is the first pole piece 121, and the winding end of the first pole piece 121 is located in the first bending area 12b. As shown in FIG.
  • the part of the first pole piece 121 beyond the winding end of the second pole piece 122 is provided with a first insulating layer 123 and a second insulating layer 124 , and the first insulating layer 123 is located outside the first pole piece 121
  • the first insulating layer 123 extends half a circle from the winding end of the first pole piece 121
  • the second insulating layer 124 is located on the inner surface of the first pole piece 121
  • the second insulating layer 124 extends from the coil of the second pole piece 122 Extend half a circle around the tail end, so that the first insulating layer 123 and the second insulating layer 124 respectively extend from the first apex to the second apex, and respectively cover a large surface.
  • the battery cell 1 provided by the present application includes two electrode assemblies 12, and the large surfaces of the two electrode assemblies 12 not covered by the first insulating layer 123 and the second insulating layer 124 abut or contact each other.
  • the large surface of each electrode assembly 12 covered by the first insulating layer 123 and the second insulating layer 124 is used to face the casing 11, so that the two electrode assemblies 12 are combined to form a double insulation closed loop, which has a better insulation effect.
  • a flame retardant layer (not shown in the figure) is stacked on the first insulating layer 123, and a getter layer (not shown in the figure) is stacked on the flame retardant layer.
  • a flame retardant layer (not shown in the figure) is stacked on the second insulating layer 124 , and a getter layer (not shown in the figure) is stacked on the flame retardant layer.

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Abstract

本申请涉及电池技术领域，具体而言，涉及一种电极组件、电池单体、电池及用电设备。电极组件包括：第一极片、第二极片和第一绝缘层，第一极片与第二极片卷绕形成电极组件，第一极片的卷绕收尾端超出第二极片的卷绕收尾端至少半圈，以使第一极片完全覆盖最外圈的第二极片的外表面，第一绝缘层涂覆于最外圈的第一极片的外表面。本申请通过将第一极片的收尾端设置为超出第二极片至少半圈，以防止第一极片收尾处松动而导致第二极片露出，并且在最外圈的第一极片表面设置第一绝缘层，以防止第一极片接触电池外壳，从而避免电池外壳带电导致安全风险和短路风险，提高电池安全性。

Description

电极组件、电池单体、电池及用电设备
相关申请的交叉引用
本申请要求享有2021年08月19日提交的名称为“电极组件、电池单体、电池及用电设备”的中国专利申请(202121958755.4)的优先权，该申请的全部内容通过引用并入本文中。
技术领域
本申请涉及电池技术领域，具体而言，涉及一种电极组件、电池单体、电池及用电设备。
背景技术
电池在新能源领域应用甚广，例如电动汽车、新能源汽车等，新能源汽车、电动汽车已经成为汽车产业的发展新趋势。电池的安全性和寿命对于用电设备而言十分重要，因此如何提高电池的安全性和循环寿命是电池技术领域的重要研究方向。
发明内容
本申请旨在提供一种电极组件、电池单体、电池及用电设备，以提高电池的安全性和循环寿命问题。
本申请的实施例是这样实现的：
第一方面，本申请实施例提供一种电极组件，其包括：
第一极片、第二极片和第一绝缘层，所述第一极片与所述第二极片卷绕形成所述电极组件，所述第一极片的卷绕收尾端超出所述第二极片的卷绕收尾端至少半圈，以使所述第一极片完全覆盖最外圈的所述第二极片的外表面，所述第一绝缘层涂覆于最外圈的所述第一极片的外表面。
本申请提供的电极组件的最外层为第一极片，通过将第一极片的收尾端设置为超出第二极片至少半圈，以防止第一极片收尾处松动而导致第二极片露出，以防析锂，提高电池的循环寿命，还防止第一极片和露出的第二极片同时接触电池外壳导致短路，从而提高电池的安全性；并且在最外圈的第一极片表面设置第一绝缘层，以防止第一极片接触电池外壳，从而进一步避免电池外壳带电导致安全风险和短路风险，提高电池安全性。
在本申请的一种实施例中，所述第一绝缘层从所述第一极片的卷绕收尾端延伸至少半圈。
在上述技术方案中，第一绝缘层包围电极组件的最外层(即电极组件的外周) 的至少半圈，两个电极组件可以组合，使两个电极组件未设置绝缘层的部分相贴，则两个电极组件的第一绝缘层共同形成绝缘闭环，将两个电极组件组合好放入电池外壳内时，能够保证电极组件和电池外壳之间绝缘隔离，从而提高电池的安全性。
在本申请的一种实施例中，所述电极组件具有平直区、第一弯折区和第二弯折区，所述平直区位于所述第一弯折区和所述第二弯折区之间，所述第一极片的卷绕收尾端位于所述第一弯折区。
电极组件的平直区即为大面所在的位置，电极组件主要是大面膨胀，大面容易接触外壳，在上述技术方案中，大面全部覆盖绝缘层，能够有效防止大面搭接外壳导致短路风险。
在本申请的一种实施例中，所述第一弯折区具有距离所述电极组件的卷绕中心最远的第一顶点，所述第二弯折区具有距离所述电极组件的卷绕中心最远的第二顶点，所述第一绝缘层覆盖所述第一顶点和所述第二顶点。
在上述技术方案中，第一绝缘层不仅环绕电极组件至少半圈，而且还覆盖第一顶点和第二顶点，这使得第一绝缘层不仅能够绝缘隔离电极组件的大面和电池外壳，还能够绝缘隔离电极组件的两端和电池外壳，确保电极组件与电池外壳容易发生接触的部位均具有第一绝缘层。
在本申请的一种实施例中，所述第一绝缘层从所述第一极片的卷绕收尾端延伸至少一圈。
在上述技术方案中，无论第一极片超出第二极片多少圈，第一绝缘层都环绕电极组件的外周至少一圈，确保电极组件的外周被第一绝缘层全部覆盖，保证绝缘效果。
在本申请的一种实施例中，所述第一绝缘层仅涂覆于所述第一极片超出所述第二极片的卷绕收尾端的部分。
在上述技术方案中，第一绝缘层仅涂覆在第一极片超出第二极片的卷绕收尾端的部分，以免第一绝缘层干扰锂离子转移，防止析锂。
在本申请的一种实施例中，所述第一极片超出所述第二极片的卷绕收尾端的部分的内表面涂覆有第二绝缘层。
在上述技术方案中，通过在电极组件的外周设置第一绝缘层，在第一极片的超出第二极片的卷绕收尾端的部分的内表面设置第二绝缘层，不仅不会干扰锂离子转移导致析锂，还能够增加绝缘层厚度，起到更好的绝缘效果。
在本申请的一种实施例中，所述第一极片超出所述第二极片的卷绕收尾端的部分的内表面或外表面涂覆有阻燃层和/或吸气层。
在上述技术方案中，所述第一极片超出第二极片的部分还可以涂其他材料，以阻燃或吸气，进一步提高安全性。
在本申请的一种实施例中，所述电极组件还包括隔膜，所述隔膜设置于所述第一极片和所述第二极片之间，所述隔膜的卷绕收尾端超出所述第一极片的卷绕收尾端至少1.75圈。
在上述技术方案中，隔膜在电极组件的外部进一步裹紧第一极片和第二极片， 增加束缚力，使第一极片的卷绕收尾端更好地贴附在次外圈的第一极片上，有效缓解第一极片的卷绕收尾端和第二极片的卷绕收尾端松散导致第一极片和第二极片之间的间隙增大的问题，从而防止间隙增大导致析锂现象，有效提高安全性。
第二方面，本申请实施例提供一种电池单体，其包括外壳和至少一个如前所述的电极组件，所述电极组件设置于所述外壳内。
第三方面，本申请实施例提供一种电池，其包括前述的电池单体。
第四方面，本申请实施例提供一种用电设备，其包括前述的电池。
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为本申请一实施例提供的车辆的结构示意图；
图2为本申请一实施例提供的电池的分解示意图；
图3为本申请一实施例提供的电池单体的分解示意图；
图4为本申请一实施例提供的电极组件的平面卷绕示意图；
图5为本申请另一实施例提供的电极组件的平面卷绕示意图；
图6为本申请一实施例提供的两个电极组件组合的结构示意图；
图7为本申请一实施例提供的三个电极组件组合的结构示意图；
图8为本申请另一实施例提供的三个电极组件组合的结构示意图；
图9为本申请又一实施例提供的电极组件的平面卷绕示意图；
图10为本申请一实施例提供的方形电极组件的平面卷绕示意图；
图11为本申请另一实施例提供的方形电极组件的平面卷绕示意图；
图12为本申请另一实施例提供的两个电极组件组合的结构示意图；
图13为本申请又一实施例提供的方形电极组件的平面卷绕示意图；
图14为本申请一实施例提供的方形电极组件的第一绝缘层环绕一圈时的结构示意图；
图15为本申请一实施例提供的圆柱形电极组件的第一绝缘层环绕一圈时的结构示意图；
图16为本申请一实施例提供的第二绝缘层的结构示意图；
图17为本申请一实施例提供的两个方形电极组件组合的立体示意图；
在附图中，附图并未按照实际的比例绘制。
标记说明：100-电池；101-箱体；1011-第一部分；1012-第二部分；1-电池单体；11-外壳；111-开口；12-电极组件；12a-平直区；12b-第一弯折区；12c-第二弯折区；121-第一极片；1211-第一极耳；122-第二极片；1221-第二极耳；123-第一绝缘层；124-第二绝缘层；125-隔膜；13-端盖组件；131-盖板；132-第一电极端子；133-第 二电极端子；200-马达；300-控制器；1000-车辆。
具体实施方式
下面将结合附图对本申请技术方案的实施例进行详细的描述。以下实施例仅用于更加清楚地说明本申请的技术方案，因此只作为示例，而不能以此来限制本申请的保护范围。
除非另有定义，本文所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同；本文中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。
在本申请实施例的描述中，技术术语“第一”“第二”等仅用于区别不同对象，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量、特定顺序或主次关系。在本申请实施例的描述中，“多个”的含义是两个以上，除非另有明确具体的限定。
在本文中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。本领域技术人员显式地和隐式地理解的是，本文所描述的实施例可以与其它实施例相结合。
在本申请实施例的描述中，术语“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
在本申请实施例的描述中，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)。
在本申请实施例的描述中，技术术语“中心”“纵向”“横向”“长度”“宽度”“厚度”“上”“下”“前”“后”“左”“右”“竖直”“水平”“顶”“底”“内”“外”“顺时针”“逆时针”“轴向”“径向”“周向”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请实施例和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请实施例的限制。
在本申请实施例的描述中，除非另有明确的规定和限定，技术术语“安装”“相连”“连接”“固定”等术语应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或成一体；也可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系。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实施例中的具体含义。
本申请中，电池单体可以包括锂离子二次电池、锂离子一次电池、锂硫电池、 钠锂离子电池、钠离子电池或镁离子电池等，本申请实施例对此并不限定。电池单体可呈圆柱体、扁平体、长方体或其它形状等，本申请实施例对此也不限定。电池单体一般按封装的方式分成三种：柱形电池单体、方形电池单体和软包电池单体，本申请实施例对此也不限定。
本申请的实施例所提到的电池是指包括一个或多个电池单体以提供更高的电压和容量的单一的物理模块。例如，本申请中所提到的电池可以包括电池模块或电池包等。电池一般包括用于封装一个或多个电池单体的箱体。箱体可以避免液体或其他异物影响电池单体的充电或放电。
电池单体包括电极组件和电解液，电极组件由正极极片、负极极片和隔膜组成。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。隔膜的材质可以为PP(polypropylene，聚丙烯)或PE(polyethylene，聚乙烯)等。
隔膜具有电子绝缘性，用于隔离相邻的正极极片和负极极片，防止相邻的正极极片和负极极片短路。隔膜具有大量贯通的微孔，能够保证电解质离子自由通过，对锂离子有很好的透过性，所以，隔膜基本上不能阻挡锂离子通过。
电池单体还包括具有开口的外壳和用于封闭开口的盖板，外壳用于容纳电极组件。
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。其中，电极组件和电池单体的外壳之间的绝缘性是影响电池的安全性能的重要因素之一，若电池单体的外壳接触电极组件而带电，存在较大的短路风险，造成安全隐患。
为解决短路问题，现有技术中一般在电极组件的外部设置一聚酯膜(mylar膜)，以用于隔离电极组件和外壳，实现绝缘的目的。然而，设置mylar膜之后，有时仍然存在绝缘失效的情况，而且有时还存在析锂现象。发明人研究发现，电极组件在充放电时会膨胀和收缩，电极组件膨胀时会将mylar膜胀大，收缩时mylar膜却不会跟电极组件一起收缩，这导致电极组件和mylar膜之间的间隙增大，电池单体内的颗粒性杂质(例如电池单体的外壳和盖板焊接过程中产生的焊渣、返工锉刀等产生的金属颗粒)容易进入增大的间隙中，当电极组件下次充电膨胀时，这些颗粒性杂质会作用于极片和mylar膜，导致极片和mylar膜因局部应力过大而变形破损，mylar膜破损则容易导致绝缘失效，从而导致安全隐患。
另外，锂离子电池单体在充电时，锂离子从正极极片脱嵌并嵌入负极极片，当负极极片嵌锂空间不足、负极极片与正极极片之间的距离过大、锂离子嵌入负极极片阻力太大或锂离子过快的从正极极片脱嵌，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极片表面得电子，从而形成银白色的金属锂单质，这就是析锂现象。而极片变形将会导致负极极片与正极极片之间的距离过大，故极片变形还容易导致析锂现象。
析锂不仅使锂离子电池单体性能下降，循环寿命大幅缩短，还限制了锂离子电池单体的快充容量。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，造成电池单体自产热起始温度降低和自产热速率增大，严重危害电池单体的安全。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膜，造成相邻的正极极片和负极极片具有短路的风险。
鉴于此，本申请发明人提供一种方案，用于解决绝缘失效问题和析锂问题，该方案中第一极片的卷绕收尾端超出第二极片的卷绕收尾端至少半圈，以使第一极片完全覆盖最外圈的第二极片的外表面，第一绝缘层涂覆于最外圈的第一极片的外表面。
在该方案中，由于取消了mylar膜，电极组件充放电时，不存在电极组件的外周面与mylar膜配合夹持颗粒物的现象，因此极片不会受到电极组件外周的颗粒物的反作用力而变形或被刺破，也不会出现由于mylar膜不同步收缩导致的析锂问题和绝缘失效问题。
通过在电极组件的最外层的极片的外表面设置第一绝缘层，第一绝缘层将电极组件容易与外壳接触的部位遮蔽，以免该部位接触外壳而缓解外壳带电短路的风险，从而提高安全性。
同时，电极组件的第一极片的卷绕收尾端超出第二极片的卷绕收尾端至少半圈，以利用第一极片完全覆盖并裹紧第二极片，防止第一极片的卷绕收尾端和第二极片的卷绕收尾端松动，以免出现第二极片的卷绕收尾端露出的问题，从而避免第一极片和露出的第二极片同时接触电池外壳而短路，从而进一步提高安全性。并避免由于第二极片局部露出，导致嵌理空间不足而析锂。
利用第一极片裹紧第二极片，还能够缓解第二极片的卷绕收尾端和第一极片之间由于松动而间隙增大的问题，以免负极极片与正极极片之间的距离过大而析锂；还防止颗粒物质进入第一极片和第二极片之间，避免下一次极片膨胀时颗粒物损伤极片和隔膜，进一步防止损伤导致析锂和短路的问题。
本申请实施例公开的电池单体可以但不限于用于车辆、船舶或飞行器等用电装置中。可以使用具备本申请公开的电池单体、电池等组成该用电装置的电源系统，这样，有利于缓解并自动调节电芯膨胀力恶化，补充电解液消耗，提升电池性能的稳定性和电池寿命。
本申请实施例提供一种使用电池作为电源的用电设备，用电设备可以为但不限于手机、平板、笔记本电脑、电动玩具、电动工具、电瓶车、电动汽车、轮船、航天器等等。其中，电动玩具可以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，航天器可以包括飞机、火箭、航天飞机和宇宙飞船等等。
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，本申请一种实施例的一种车辆1000，车辆1000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1000的内部可以设置电池100、控制器300以及马达200，控制器300用来控制电池100为马达200的供电。例如，在车辆1000的底部或车头或车尾可以设置电池100。电池100可以用于车辆1000的供电，例如，电池100可以作为车辆1000的操作电源，用于车辆1000的电路系统，例如，用于车辆1000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100不仅仅可以作为车辆1000的操作电源，还可以作为车辆1000的驱动电源，替代或部分地替代燃油或天然气为车辆1000提供驱动动力。
为了满足不同的使用电力需求，电池100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100也可以称为电池包。可选地，请结合图2所示，多个电池单体1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100。也就是说，多个电池单体1可以直接组成电池100，也可以先组成电池模块，电池模块再组成电池100。
电池100可以包括多个电池单体1。电池100还可以包括箱体101(或称罩体)，箱体101内部为中空结构，多个电池单体1容纳于箱体101内。箱体101可以包括两个用于容纳的部分(可参照图2)，这里分别称为第一部分1011和第二部分1012，第一部分1011和第二部分1012扣合在一起。第一部分1011和第二部分1012的形状可以根据多个电池单体1组合的形状而定，第一部分1011和第二部分1012可以均具有一个开口。例如，第一部分1011和第二部分1012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1011的开口和第二部分1012的开口相对设置，并且第一部分1011和第二部分1012相互扣合形成具有封闭腔室的箱体101。第一部分1011和第二部分1012中，也可以一者为具有开口的长方体，另一者为盖板结构以封闭长方体的开口。多个电池单体1相互并联或串联或混联组合后置于第一部分1011和第二部分1012扣合后形成的箱体101内。
可选地，电池100还可以包括其他结构。例如，该电池100还可以包括汇流部件，汇流部件用于实现多个电池单体1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1的电极端子实现电池单体1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1的电极端子。多个电池单体1的电能可进一步通过导电机构穿过箱体101而引出。可选地，导电机构也可属于汇流部件。
下面针对任意一个电池单体1进行详细描述，图3示出了本申请一个实施例的电池单体1，电池单体1包括外壳11、端盖组件13和电极组件12及其他功能性部件。
外壳11根据电极组件12的形状而定，例如，外壳11可以为中空的长方体或正方体或圆柱体，且外壳11的其中一个面具有开口111以便一个或多个电极组件12可以放置于外壳11内。例如，当外壳11为中空的长方体或正方体时，外壳11的其中一个平面为具有开口111的平面，该平面被配置为不具有壁体而使得外壳11内外相通。
电极组件12是电池单体1中发生电化学反应的部件。外壳11内可以包含一个或更多个电极组件12。电极组件12主要由正极极片和负极极片卷绕或层叠放置形成，并且通常在正极极片和负极极片之间设有隔膜125。正极极片和负极极片具有活性物质的部分构成电极组件12的主体部，正极极片和负极极片不具有活性物质的部分各自构成极耳。正极极耳和负极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。在电池的充放电过程中，正极活性物质和负极活性物质与电解液发生反应。电极端子的数量为两个，转接片的数量也为两个，正极极耳与一个电极端子通过一个转接片连接，负极极耳与另一个电极端子通过另一个转接片连接。
端盖组件13用于覆盖开口111并与外壳11连接，以形成用于放置电极组件12的封闭腔体，该封闭腔体与外部环境隔绝，用于容纳电极组件12及电解质(例如电解液)等。端盖组件13包括盖板131，盖板131用于封闭开口111并与外壳11连接。该端盖组件13还包括第一电极端子132和第二电极端子133，第一电极端子132和第二电极端子133可以设置在盖板131上。盖板131通常整体呈平板状，第一电极端子132和第二电极端子133固定在盖板131的平板面上，第一电极端子132和第二电极端子133用于与电极组件12电连接。
根据本申请的一些实施例，本申请提供的电极组件12可以为圆柱形、也可以为扁平状等其他形状，请参照图4，图4示出了本申请一实施例的圆柱形的电极组件12的卷绕结构平面示意图，该电极组件12包括第一极片121、第二极片122和第一绝缘层123，第一极片121与第二极片122卷绕形成电极组件12，第一极片121的卷绕收尾端超出第二极片122的卷绕收尾端至少半圈，以使第一极片121完全覆盖最外圈的第二极片122的外表面，第一绝缘层123涂覆于最外圈的第一极片121的外表面。
本申请的电极组件12，其第一极片121和第二极片122极性相反，本申请实施例中第一极片121可以为负极极片，第二极片122可以为正极极片。第一极片121和第二极片122层叠后卷绕成型，其中第一极片121设有第一极耳1211，第二极片122上设有第二极耳1221(参见图3)，第一极耳1211用于连接第一电极端子132，第二极耳1221用于连接第二电极端子133。本申请中的一圈是指：从电极组件12的某个点为起始点，沿卷绕方向一周到达另一个点，该另一个点与起始点的连线沿电极组件12的径向。本申请中的半圈是指一圈的一半，0.75圈是指一圈的0.75,本领域技术人员应理解其他圈数的含义，在此不再穷举详述。
第一极片121的卷绕收尾端超出第二极片122的卷绕收尾端至少半圈，即，第二极片122收尾后，第一极片121继续卷绕，直至完全覆盖第二极片122，并且第一极片121在完全覆盖第二极片122后，仍继续卷绕半圈后再收尾，此时，电极组件12的最外层为第一极片121，第一极片121超出第二极片122的卷绕收尾端的位置处，电极 组件12的最外层和次外层均为第一极片121。
由此，可利用第一极片121裹紧第二极片122，防止第一极片121的卷绕收尾端和第二极片122的卷绕收尾端松动导致出现第二极片122的卷绕收尾端露出至电极组件12的外表，延伸的第一极片121的卷绕收尾端能够保证第二极片122始终处于第一极片121的覆盖范围内，从而保证电极组件12朝向外壳11的外周均为第一极片121，防止第一极片121和露出的第二极片122同时接触电池100外壳11而短路。
第二极片122始终处于第一极片121的覆盖范围内，还避免第二极片122露出部分缺少对应的第一极片121而出现嵌锂空间不足的问题，避免析锂。第一极片121的收尾端延长还提高了束缚力，缓解第一极片121的收尾端松动导致第一极片121和第二极片122之间间隙增大的问题，避免析锂。从而，避免析锂损伤极片、导致短路，保证电池100的循环寿命和安全性。
第一绝缘层123设置在电极组件12可能会与外壳11接触的外周，也即，设置在电极组件12的最外层的第一极片121的外表面，第一绝缘层123将电极组件12容易接触外壳11的部位遮蔽，从而绝缘隔离电极组件12和外壳11，提高电池100的安全性。
本申请中第一绝缘层123的覆盖部位和覆盖范围有多种设置。
根据本申请的一实施例，第一绝缘层123从第一极片121的卷绕收尾端延伸至少半圈。
如图4所示，第一极片121的卷绕收尾端超出第二极片122的卷绕收尾端半圈，第一绝缘层123涂覆于第一极片121超出第二极片122的部分，也即第一绝缘层123沿反向于极片卷绕方向的方向，从第一极片121的卷绕收尾端开始延伸半圈。
在一些实施例中，第一绝缘层123也可以沿极片卷绕方向延伸，从第一极片121的卷绕收尾端开始延伸半圈，如图5所示，图5示出了另一实施例的电极组件12的卷绕结构平面示意图，第一绝缘层123位于第一极片121未超出第二极片122的部分。
在一些实施例中，第一绝缘层123也可以一部分位于第一极片121超出第二极片122的部分，另一部分位于第一极片121未超出第二极片122的部分。
图6示出了一种由两个电极组件12组成的组合，两个电极组件12未设置有第一绝缘层123的外周表面靠近或接触，以使两个电极组件12设有第一绝缘层123的外周表面朝向外壳11的内壁，从而，保证电极组件12朝向外壳11的任意部位都被第一绝缘层123遮蔽，两个电极组件12组合形成绝缘闭环，有效防止短路，提高了安全性。
在一些实施例中，也可以将三个及以上的电极组件12组成组合后再装入外壳11。
图7示出了三个电极组件12的一种组合，如图7所示，三个电极组件12呈三角形摆放，每个电极组件12的最外层的第一极片121的表面设有半圈第一绝缘层123，每个电极组件12未设置有第一绝缘层123的外周表面相对，以使两个电极组件12设有第一绝缘层123的外周表面朝向外壳11的内壁，从而形成绝缘闭环。
图8示出了三个电极组件12的另一种组合，如图8所示，三个电极组件12依次排列，位于两端的电极组件12的最外层的第一极片121的表面设有半圈第一绝缘层123，位于中间的电极组件12垂直于排列方向的两端顶点处设有第一绝缘层123，图9示出了位于中间的电极组件12的卷绕结构。三个电极组件12中，每个电极组件12未设有第一绝缘层123的外周表面均朝向相邻的电极组件12，而设有第一绝缘层123的外周表面朝向外壳11，从而形成绝缘闭环。
根据本申请的一些实施例，电极组件12具有平直区12a、第一弯折区12b和第二弯折区12c，平直区12a位于第一弯折区12b和第二弯折区12c之间，第一极片121的卷绕收尾端位于第一弯折区12b，第一绝缘层123从第一极片121的卷绕收尾端延伸至少半圈。
如图10所示，图10示出了一实施例的电极组件卷绕结构图，电极组件12呈扁平状。电极组件12可以是直接卷绕成扁平状；也可以是被卷绕成圆形或椭圆形后，再将电极组件12的中部压紧、压密实，使得电极组件12的中部形成平直区12a，平直区12a的两端为弯折区(即第一弯折区12b和第二弯折区12c)。平直区12a具有两个相对的表面，第一弯折区12b和第二弯折区12c分别具有一个弧形表面，相对而言，平直区12a的任一表面都大于第一弯折区12b或第二弯折区12c的弧形表面，平直区12a的任一表面常被称为大面。
第一极片121的卷绕收尾端位于第一弯折区12b，第一绝缘层123从第一极片121的卷绕收尾端延伸至少半圈，第一绝缘层123的延伸方向可以是沿电极组件12的卷绕方向，也可以是反向于电极组件12的卷绕方向。如图10所示，第一绝缘层123沿反向于极片卷绕方向的方向，从第一极片121的卷绕收尾端开始延伸半圈，第一绝缘层123涂覆于第一极片121超出第二极片122的部分。如图11所示，第一绝缘层123沿极片卷绕方向延伸，从第一极片121的卷绕收尾端开始延伸半圈，第一绝缘层123位于第一极片121未超出第二极片122的部分。
从而，电极组件12的平直区12a的一侧表面，也即电极组件12的一侧大面及该侧大面相邻的部位，均具有第一绝缘层123。由于电极组件12与外壳11之间一般具有间隙，电极组件12在充放电膨胀时，主要是平直区12a(即大面所在位置)膨胀，因此平直区12a容易接触外壳11，通过在电极组件12的一侧大面设置第一绝缘层123，能够有效防止大面搭接外壳11导致短路的风险。
图12示出了一种由两个电极组件12组成的组合，两个电极组件12呈扁平状，两个电极组件12未设置有第一绝缘层123的外周表面靠近或接触，以使两个电极组件12设有第一绝缘层123的外周表面朝向外壳11的内壁，也就是说，两个电极组件12未设置有第一绝缘层123一侧的大面靠近或接触，设有第一绝缘层123一侧的大面朝向外壳11，从而保证电极组件12朝向外壳11的任意部位都被第一绝缘层123遮蔽，两个电极组件12组合形成绝缘闭环，有效防止短路，提高了安全性。
根据本申请的一些实施例，第一弯折区12b具有距离电极组件12的卷绕中心最远的第一顶点，第二弯折区12c具有距离电极组件的卷绕中心最远的第二顶点，第一绝缘层123覆盖第一顶点和第二顶点。
电极组件12卷绕成型并被压扁成扁平状后，请再参照图10或图11，距离卷绕中心最远的两个顶点(第一顶点和第二顶点)位于扁平状的两端，电极组件12入壳后，除了大面容易接触外壳11以外，电极组件12的第一顶点和第二顶点也可能接触外壳11。通过设置第一绝缘层123，使第一顶点和第二顶点被第一绝缘层123覆盖，有效缓解第一顶点和第二顶点接触外壳11导致短路的问题。
在一些实施例中，三个及以上的电极组件12依次排列且大面贴合时：位于排列方向两端的电极组件12的朝向外壳11大面设置第一绝缘层123，其第一绝缘层123由第一顶点延伸至第二顶点，如图10或图11所示；位于排列方向的中间的电极组件12，仅在第一顶点和第二顶点所在位置设有第一绝缘层123，如图13所示。从而，三个电极组件12组合的整体可能与外壳接触的部位都被第一绝缘层123覆盖，因此沿三个电极组件12组合的整体的周向上形成绝缘闭环，防止短路。
根据本申请的一些实施例，第一绝缘层123从第一极片121的卷绕收尾端延伸至少一圈。
如图14和图15所示，第一绝缘层123以第一极片121的卷绕收尾端为起始点，环绕电极组件12的外周一圈，确保电极组件12的外周被第一绝缘层123全部覆盖，单个电极组件12形成绝缘闭环，从而保证绝缘隔离电极组件12和外壳11的效果。
在一些实施例中，第一绝缘层123环绕电极组件12的外周一圈后，继续延伸一定长度，以防止第一极片121的收尾端松动时未设有第一绝缘层123的部位露出外周并接触外壳11导致短路。
根据本申请的一些实施例，第一绝缘层123仅涂覆于第一极片121超出第二极片122的卷绕收尾端的部分。
第一极片121未超出第二极片122的卷绕收尾端的部分需要接收锂离子，通过将第一绝缘层123仅涂覆在第一极片121超出第二极片122的卷绕收尾端的部分，以免第一绝缘层123影响第一极片121接收锂离子，防止出现析锂问题。
例如，图4、图10所示，第一极片121超出第二极片122的卷绕收尾端至少半圈，第一绝缘层123从第一极片121的卷绕收尾端出发沿反向于极片卷绕方向的反向延伸半圈。
当然，在其他实施例中，第一绝缘层123也可以不从第一极片121的卷绕收尾端出发，而仅从第一极片121超出第二极片122的卷绕收尾端的部分的其他位置出发，并在第一极片121超出第二极片122的卷绕收尾端的部分的范围内延伸。例如，图9、图13所示，第一极片121超出第二极片122的卷绕收尾端的部分的局部位置设有第一绝缘层123。
根据本申请的一些实施例，第一极片121超出第二极片122的卷绕收尾端的部分的内表面涂覆有第二绝缘层124。
如图16所示，除了在第一极片121的最外圈的外表面设置第一绝缘层123外，还在第一极片121超出第二极片122的卷绕收尾端的部分的内表面涂覆第二绝缘层124。
由于第一极片121超出第二极片122的卷绕收尾端的部分不需要用于接收锂离子，因此第二绝缘层124不会影响第一极片121的嵌锂空间，不会导致析锂问题，还能够增加绝缘层的厚度，起到更好的绝缘效果。并且，即使尖锐物体刺破外壳11刺穿第一极片121超出第二极片122的卷绕收尾端的部分，第二绝缘层124也能够隔离次外圈的第二极片122与尖锐物体、外壳11，从而进一步起到绝缘效果。
在一些实施例中，如图16所示，第一极片121超出第二极片122的卷绕收尾端至少一圈，第一绝缘层123和第二绝缘层124均设置在第一极片121超出第二极片122的卷绕收尾端的部分，且第一绝缘层123的延伸长度为至少一圈，第二绝缘层124的延伸长度为至少一圈，从而电极组件12的外周形成双重绝缘闭环。
本申请中的第一绝缘层123和第二绝缘层124可以由相同的材料制成，也可以分别使用不同的材料制成。
具体地，构成第一绝缘层123、第二绝缘层124的材料可以为：包括氧化铝、氧化锆、二氧化钛、氧化镁、高聚物和亲水链段修饰的聚半倍硅氧烷中的一种或多种。
或者，构成第一绝缘层123、第二绝缘层124的材料也可以是油性材料，如：液体氟橡胶、液体硅橡胶、液体聚硫橡胶、端羟基聚丁二烯中的一种与甲苯的混合物；或者，包括液体氟橡胶、液体硅橡胶、液体聚硫橡胶、端羟基聚丁二烯中的一种与水溶剂的混合物。上述混合物涂覆在第一极片121的表面，常下为液态胶体，从而在第一极片121表面形成稳定的绝缘层，遭受穿刺后(如被颗粒物刺破、被外部尖锐物体刺破或被变形的外壳11刺破)发生流动并受到电极组件12产生的热量而固化，从而再次形成稳定的绝缘层。因此，油性材料形成的第一绝缘层123或第二绝缘层124即使受到穿刺也具有重新绝缘的可能，具有较好的绝缘稳定性。并且，若第一极片121形成刺穿的穿孔或凹槽，油性材料还能够流动到穿孔中或凹槽中，使穿孔的内壁或凹槽的内壁被油性材料覆盖，油性材料受热固化并在新的覆盖位置形成绝缘层，以免穿刺孔暴露，起到阻止或延缓短路时间的作用。
根据本申请的一些实施例，第一极片121超出第二极片122的卷绕收尾端的部分的内表面或外表面涂覆有阻燃层和/或吸气层(图中未示出)。
也即，前述的第二绝缘层124可以替换为阻燃层和吸气层中的一者，或者第二绝缘层124被替换为层叠设置在第一极片121的内表面上的阻燃层和吸气层；或者，在第一绝缘层123上层叠涂覆阻燃层和吸气层中的至少一者；或者，在第二绝缘层124上层叠涂覆阻燃层和吸气层中的至少一者。
阻燃层的材料包括氢氧化铝、拟薄水铝石、薄水铝石、氢氧化锆、碳酸镁、碱式碳酸镁、碳酸钙中的一种或多种。
当最外层的第一极片121接触外壳11，且发生绝缘异常，导致接触点短路升温燃烧时，在阻燃层的隔离作用下，能够阻止燃烧继续向电极组件12的内部发展，从而减小燃烧程度，降低安全风险。
吸气层的材料可以为辅酶素Q10(coenzyme Q10)，也即泛醌10，是一种脂溶性醌环类化合物。锂离子电池中，由于电化学反应或电解液分解等原因，可能会 产生一些氧化性气体，比如氧气。辅酶素Q10能够转移电极组件12内部的氧化性气体，将电极组件12发生电化学反应时的副产物还原成氧化锂，从而减少电池内部的气体，降低内压，提高安全性。
根据本申请的一些实施例中，电极组件12还包括隔膜125，隔膜125设置于第一极片121和第二极片122之间，请再参见图15，隔膜125的卷绕收尾端超出第一极片121的卷绕收尾端至少1.75圈。
也即，隔膜125的卷绕收尾端从第一极片121的卷绕收尾端为起始点，继续延伸并卷绕一周，然后继续卷绕0.75圈以上后收尾固定。
第一极片121和第二极片122之间的隔膜125，能够隔离第一极片121和第二极片122，以免第一极片121和第二极片122接触短路。隔膜125的长度大于第一极片121的长度，隔膜125超出第一极片121的卷绕收尾端的部分进一步裹紧第一极片121和第二极片122，增加束缚力，防止第一极片121的卷绕收尾端松动，并能够更好地固定第二极片122的卷绕收尾端，从而防止第一极片121和第二极片122在收尾处间隙增大，以免出现极片间距增大导致析锂的问题，进而也避免附着的锂结晶刺破隔膜125，造成第一极片121和第二极片122短路，从而有效提高安全性。
根据本申请的一些实施例，本申请还提供一种电池单体1，其包括外壳11和至少一个前述的电极组件12，电极组件12设置在外壳11内。
根据本申请的一些实施例，本申请还提供一种电池100，该电池100包括前述的电池单体1。
根据本申请的一些实施例，本申请还提供一种用电设备，该用电设备包括前述的电池100。
根据本申请的一些实施例，请参照图3和图10，本申请提供一种电极组件12，电极组件12由第一极片121、第二极片122及隔膜125层叠后卷绕形成，电极组件12卷绕成圆形后，中部被压至紧密而呈扁平状，使得电极组件12包括平直区12a、第一弯折区12b和第二弯折区12c，其中平直区12a位于第一弯折区12b和第二弯折区12c之间。第一极片121超出第二极片122的卷绕收尾端至少半圈，使得第一极片121完全覆盖第二极片122的卷绕最外圈的外表面，电极组件12的最外层(即第一极片121超出第二极片122的卷绕收尾端的半圈)和次外层(即第一极片121覆盖最外圈的第二极片122的外表面的一圈)都是第一极片121，第一极片121的卷绕收尾端位于第一弯折区12b。如图10所示，第一极片121超出第二极片122的卷绕收尾端的部分设有第一绝缘层123和第二绝缘层124，第一绝缘层123位于第一极片121的外表面，第一绝缘层123从第一极片121的卷绕收尾端延伸半圈，第二绝缘层124位于第一极片121的内表面，第二绝缘层124从第二极片122的卷绕收尾端延伸半圈，使得第一绝缘层123、第二绝缘层124分别由第一顶点延伸至第二顶点，并分别覆盖一个大面。如图17所示，本申请提供的电池单体1包括两个电极组件12，两个电极组件12未被第一绝缘层123和第二绝缘层124覆盖的大面相互靠接或接触，两个电极组件12被第一绝缘层123和第二绝缘层124覆盖的大面用于朝向外壳11，从而两个电极组件12组合后形成双重绝缘闭环，起到较好的绝缘效果。进一步地，第一绝缘层123上还层叠设置 有阻燃层(图中未示出)，并在阻燃层上层叠设置有吸气层(图中未示出)。进一步地，第二绝缘层124上还层叠设置有阻燃层(图中未示出)，并在阻燃层上层叠设置有吸气层(图中未示出)。
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 (12)

  1. 一种电极组件，包括第一极片、第二极片和第一绝缘层，所述第一极片与所述第二极片卷绕形成所述电极组件，所述第一极片的卷绕收尾端超出所述第二极片的卷绕收尾端至少半圈，以使所述第一极片完全覆盖最外圈的所述第二极片的外表面，所述第一绝缘层涂覆于最外圈的所述第一极片的外表面。
  2. 根据权利要求1所述的电极组件，其特征在于，所述第一绝缘层从所述第一极片的卷绕收尾端延伸至少半圈。
  3. 根据权利要求2所述的电极组件，其特征在于，所述电极组件具有平直区、第一弯折区和第二弯折区，所述平直区位于所述第一弯折区和所述第二弯折区之间，所述第一极片的卷绕收尾端位于所述第一弯折区。
  4. 根据权利要求3所述的电极组件，其特征在于，所述第一弯折区具有距离所述电极组件的卷绕中心最远的第一顶点，所述第二弯折区具有距离所述电极组件的卷绕中心最远的第二顶点，所述第一绝缘层覆盖所述第一顶点和所述第二顶点。
  5. 根据权利要求1-4中任一项所述的电极组件，其特征在于，所述第一绝缘层从所述第一极片的卷绕收尾端延伸至少一圈。
  6. 根据权利要求1-5中任一项所述的电极组件，其特征在于，所述第一绝缘层仅涂覆于所述第一极片超出所述第二极片的卷绕收尾端的部分。
  7. 根据权利要求1-6中任一项所述的电极组件，其特征在于，所述第一极片超出所述第二极片的卷绕收尾端的部分的内表面涂覆有第二绝缘层。
  8. 根据权利要求1-7中任一项所述的电极组件，其特征在于，所述第一极片超出所述第二极片的卷绕收尾端的部分的内表面或外表面涂覆有阻燃层和/或吸气层。
  9. 根据权利要求1-8任一项所述的电极组件，其特征在于，所述电极组件还包括隔膜，所述隔膜设置于所述第一极片和所述第二极片之间，所述隔膜的卷绕收尾端超出所述第一极片的卷绕收尾端至少1.75圈。
  10. 一种电池单体，其特征在于，包括外壳和至少一个如权利要求1-9任一项所述的电极组件，所述电极组件设置于所述外壳内。
  11. 一种电池，其特征在于，包括权利要求10所述的电池单体。
  12. 一种用电设备，其特征在于，包括权利要求11所述的电池。
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