CN222775554U - Battery cells, batteries and electrical devices - Google Patents

Abstract

The present application provides a battery cell, a battery and an electrical device, the battery cell comprising a shell and an electrode assembly contained in the shell, the electrode assembly comprising a first pole piece and a second pole piece with opposite polarities; the first pole piece comprising a first current collecting body and a first active material layer arranged on the surface of the first current collecting body, the first active material layer comprising a main body area and a thinning area, the thickness of at least part of the thinning area is less than the thickness of the main body area, the thinning area is located on one side of the main body area along a first direction, and the first direction is perpendicular to the thickness direction of the first current collecting body; the electrode assembly also includes an insulating member, at least part of the insulating member is arranged between the first pole piece and the second pole piece, the insulating member is connected to the surface of the thinning area away from the first current collecting body, and along the direction of the first current collecting body pointing to the first active material layer, the surface of the insulating member away from the first current collecting body does not exceed the surface of the main body area away from the first current collecting body. The present application can improve reliability.

Description

Battery monomer, battery and power consumption device

Technical Field

The present application relates to the field of battery technologies, and in particular, to a battery cell, a battery, and an electric device.

Background

Battery cells are widely used in electronic devices such as cellular phones, notebook computers, battery cars, electric vehicles, electric airplanes, electric ships, electric toy vehicles, electric toy ships, electric toy airplanes, electric tools, and the like. In the development of battery technology, how to improve the reliability of a battery cell is one research direction in battery technology.

Disclosure of utility model

In view of the above, the present application provides a battery cell, a battery, and an electric device, which can improve reliability.

In a first aspect, the application provides a battery cell comprising a shell and an electrode assembly accommodated in the shell, wherein the electrode assembly comprises a first electrode plate and a second electrode plate with opposite polarities, the first electrode plate comprises a first current collecting main body and a first active material layer arranged on the surface of the first current collecting main body, the first active material layer comprises a main body area and a thinning area, at least part of the thickness of the thinning area is smaller than that of the main body area, and the thinning area is positioned on one side of the main body area along a first direction. The electrode assembly further comprises an insulating part, at least part of the insulating part is arranged between the first pole piece and the second pole piece and is arranged on one side of the first active material layer along the first direction, the insulating part comprises a first insulating part, the first insulating part is connected to the surface of the thinning area, which is away from the first current collecting main body, along the direction, which is pointed to the first active material layer, of the first current collecting main body, and the first insulating part does not exceed the surface, which is away from the first current collecting main body, of the main body area.

In the scheme, the insulating piece is at least partially arranged between the first pole piece and the second pole piece, so that the metal burrs can be prevented from conducting the first pole piece and the second pole piece, and the possibility of thermal runaway caused by short circuit is reduced. The arrangement of the first insulating part can increase the connection strength of the insulating part and the first pole piece connection, reduce the possibility of the increase of the overall thickness of the electrode assembly, reduce the thickness difference of the middle area and the end area of the electrode assembly, reduce the risk of winding dislocation caused by inconsistent tension of the two ends of the electrode assembly along the first direction in the winding process of the electrode assembly, and improve the reliability of the battery cell.

In some embodiments, the insulator comprises a first insulator portion comprising a first portion and a second portion, the second portion being located at an end of the first portion proximate the body region, the second portion having a thickness less than a thickness of the first portion.

In the scheme, the process error of the insulating part is increased, the possibility that the first insulating part protrudes out of the main body area due to the fact that the thickness of the first insulating part is too thick is reduced, and the thickness difference of the middle area and the end area of the electrode assembly is reduced.

In some embodiments, the thickness of the thinned region gradually decreases in a direction from the body region toward the thinned region.

In the scheme, through the arrangement, the manufacturing difficulty of the thinning area is reduced, the manufacturing precision of the thinning area is reduced, and the production efficiency is improved.

In some embodiments, the insulator includes a first insulator portion connected to a surface of the thinned region facing away from the first current collecting body, the first insulator portion having a thickness that gradually increases in a direction from the body region toward the thinned region.

In the scheme, through the arrangement, the process error of the insulating piece is increased, and the possibility that the insulating piece increases the whole thickness of the first pole piece is reduced.

In some embodiments, the insulator includes a first insulator portion and a second insulator portion, the first insulator portion being connected to a surface of the thinned region facing away from the first current collecting body. The first current collecting body includes a coated region and an uncoated region disposed along a first direction, and the second insulating portion is disposed at the uncoated region.

In the scheme, through the arrangement, the blocking area of the insulating piece to the first pole piece is increased, and the possibility that the metal burrs conduct the first pole piece and the second pole piece is further reduced.

In some embodiments, the first current collecting body has a first end surface at one end in the first direction, and the second insulating portion extends from the one end of the first insulating portion in the first direction and is disposed to cover the first end surface.

In the scheme, through the arrangement, the connecting area of the insulating piece and the first pole piece is further increased, the connecting strength of the insulating piece and the first pole piece is improved, and the possibility that burrs on the first end face of the first current collecting main body conduct the first pole piece and the second pole piece is reduced.

In some embodiments, a side surface of the thinned region facing away from the main body region in the first direction is a second end surface, the first end surface and the second end surface are disposed flush, and the second insulating portion covers the first end surface and the second end surface. According to the embodiment of the application, the difference between the sizes of the first current collecting main body and the first active material layer along the first direction can be reduced, the waste of the first current collecting main body is reduced, the energy density is improved, the connection area of the second insulating part and the first pole piece is increased, the risk that the insulating part falls off from the first pole piece is reduced, and the reliability is improved.

In some embodiments, the uncoated region includes an empty foil region and a first tab protruding from the empty foil region, and a portion of the insulator is disposed on a surface of the first tab.

In the scheme, through setting up empty foil area, increase the connection area of insulating part and first pole piece, improve the connection degree of difficulty of insulating part and first pole piece, reduce first pole piece and cut the risk of first active material layer in cutting the in-process, reduce the waste of active material. Through setting up the surface at first utmost point ear with partial insulating part, reduce the burr that first utmost point ear cut back edge formed and switch on first pole piece and second pole piece's possibility, further improve battery monomer's reliability.

In some embodiments, the second insulating portion completely covers the uncoated region, so as to reduce the possibility of conduction between the uncoated region and the second pole piece, reduce the risk of short circuit, and improve the reliability.

In some embodiments, the minimum thickness of the second insulating portion is greater than the minimum thickness of the first insulating portion.

In the scheme, through the arrangement, the manufacturing difficulty of the insulating piece can be reduced, the manufacturing cost of the insulating piece is reduced, the tensile strength of the insulating piece is increased, and the risk of falling off of the insulating piece is reduced.

In some embodiments, the first active material layer is disposed on two side surfaces of the first current collecting body, and the insulating member is disposed on two sides of the first current collecting body, and the two insulating members are connected.

In the scheme, through setting up two insulating parts and being connected the second insulating part of two insulating parts, can increase the area of connection of insulating part and first pole piece, reduce the risk that the insulating part drops. The second insulating portion may separate burrs on the first end face from the second pole piece, thereby reducing the risk of short circuits.

In some embodiments, the porosity of the insulation is 30% -40%. The insulator has a high porosity to reduce resistance to ions passing through the insulator.

In some embodiments, the battery cell further includes a separator for separating the first pole piece and the second pole piece. In the first direction, the insulating member does not protrude beyond the spacer, thereby reducing the space that the insulating member additionally occupies in the first direction.

In a second aspect, an embodiment of the present application provides a battery comprising a battery cell according to any one of the preceding embodiments.

In a third aspect, an embodiment of the present application provides an electrical device, including a battery according to any one of the foregoing embodiments, where the battery is configured to provide electrical energy.

The foregoing description is only an overview of the present application, and is intended to be implemented in accordance with the teachings of the present application in order that the same may be more clearly understood and to make the same and other objects, features and advantages of the present application more readily apparent.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments of the present application will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort to a person of ordinary skill in the art.

FIG. 1 is a schematic illustration of a vehicle according to some embodiments of the present application;

Fig. 2 is an exploded view of a battery according to some embodiments of the present application;

fig. 3 is an exploded view of a battery cell according to some embodiments of the present application;

FIG. 4 is a schematic top view of an electrode assembly according to some embodiments of the present application;

FIG. 5 is a schematic view in partial cross-section taken along the direction A-A of FIG. 4;

fig. 6 is an enlarged schematic view of the block P in fig. 5;

FIG. 7 is a schematic illustration of an electrode assembly according to some embodiments of the present application in a flattened state after a first electrode tab and an insulator are connected;

FIG. 8 is a schematic view in partial section taken along the direction B-B of FIG. 7;

Fig. 9 is a schematic view in partial cross-section taken along the direction B-B of fig. 7.

Description of the marking

1.2, A battery, 3, a controller, 4, a motor, 5, a box body, 5a, a first box body part, 5b, a second box body part, 5c, an accommodating space and 6, a battery monomer;

100. 200, the outer casing;

10. the electrode comprises a first electrode plate, 11 parts of a first current collecting main body, 111 parts of a first end face, 112 parts of a coating area, 113 parts of an uncoated area, 113a parts of a first electrode lug, 113b parts of an empty foil area, 12 parts of a first active material layer, 121 parts of a main body area, 122 parts of a thinning area, 122a parts of a second end face;

20. a second pole piece;

30. 31, first insulating part, 311, first part, 312, second part, 32, second insulating part;

40. A spacer;

x, thickness direction, Y, first direction, V, winding direction.

Detailed Description

Embodiments of the technical scheme of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present application, and thus are merely examples, and are not intended to limit the scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs, the terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting of the application, and the terms "comprising" and "having" and any variations thereof in the description of the application and the claims and the above description of the drawings are intended to cover non-exclusive inclusions.

In the description of embodiments of the present application, the technical terms "first," "second," and the like are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship. In the description of the embodiments of the present application, the meaning of "plurality" is two or more unless explicitly defined otherwise.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases 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 of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

In the description of the embodiment of the present application, the term "and/or" is merely an association relationship describing the association object, and indicates that three relationships may exist, for example, a and/or B, and may indicate that a exists alone, while a and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

In the description of the embodiments of the present application, the term "plurality" means two or more (including two), and similarly, "plural sets" means two or more (including two), and "plural sheets" means two or more (including two).

In the description of the embodiments of the present application, the orientation or positional relationship indicated by the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of description and simplification of the description, and do not indicate or imply that the apparatus or element referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the embodiments of the present application.

In the description of the embodiments of the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "fixed" and the like are to be construed broadly and include, for example, fixed connection, detachable connection, or integral therewith, mechanical connection, electrical connection, direct connection, indirect connection via an intermediary, communication between two elements, or interaction between two elements. The specific meaning of the above terms in the embodiments of the present application will be understood by those of ordinary skill in the art according to specific circumstances.

In the embodiment of the application, the battery cell can be a secondary battery, and the secondary battery refers to a battery cell which can activate the active material in a charging mode to continue to use after the battery cell discharges.

The battery cell may be a lithium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead storage battery, etc., which is not limited by the embodiment of the application.

The battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge of the battery cell, active ions (e.g., lithium ions) are inserted and extracted back and forth between the positive electrode and the negative electrode. The separator is arranged between the positive electrode and the negative electrode, can play a role in preventing the positive electrode and the negative electrode from being short-circuited, and can enable active ions to pass through.

In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

As an example, the positive electrode current collector has two surfaces opposing in its own thickness direction, and the positive electrode active material is provided on either or both of the two surfaces opposing the positive electrode current collector.

As an example, the positive electrode current collector may employ a metal foil or a composite current collector. For example, as the metal foil, silver-surface-treated stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, titanium, or the like can be used. The composite current collector may include a polymeric material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a polymer material substrate (e.g., polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

In some embodiments, the negative electrode may be a negative electrode tab, which may include a negative electrode current collector.

As an example, the negative electrode current collector may employ a metal foil, a metal foam, a carbon foam, or a composite current collector. For example, as the metal foil, silver-surface-treated stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, titanium, or the like can be used. The foam metal can be foam nickel, foam copper, foam aluminum or foam alloy. The composite current collector may include a polymeric material base layer and a metal layer. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a polymer material substrate (e.g., polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

As an example, the anode current collector has two surfaces opposing in its own thickness direction, and the anode active material is provided on either or both of the two surfaces opposing the anode current collector.

As an example, a negative active material for a battery cell, which is well known in the art, may be used. As an example, the anode active material may include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, lithium titanate, and the like.

In some embodiments, the material of the positive electrode current collector may be aluminum and the material of the negative electrode current collector may be copper.

In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

In some embodiments, the separator is a separator film. The type of the separator is not particularly limited, and any known porous separator having good chemical stability and mechanical stability can be used.

As an example, the main material of the separator may be at least one selected from glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic.

In some embodiments, the separator is a solid state electrolyte. The solid electrolyte is arranged between the anode and the cathode and plays roles in transmitting ions and isolating the anode and the cathode.

In some embodiments, the battery cell further includes an electrolyte that serves to conduct ions between the positive and negative electrodes. The application is not particularly limited in the kind of electrolyte, and may be selected according to the need. The electrolyte may be liquid, gel or solid.

In some embodiments, the electrode assembly is a rolled structure. The positive plate and the negative plate are wound into a winding structure.

In some embodiments, the electrode assembly is a lamination stack.

In some embodiments, the electrode assembly may have a cylindrical shape, a flat shape, a polygonal column shape, or the like.

In some embodiments, the electrode assembly is provided with tabs that can conduct current away from the electrode assembly. The tab includes a positive tab and a negative tab.

In some embodiments, the battery cell may include a housing. The case is used to encapsulate the electrode assembly, the electrolyte, and the like. The shell can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), an aluminum-plastic film or the like.

In some embodiments, the housing may be provided with functional components such as electrode terminals. The electrode terminals may be used to be electrically connected with the electrode assembly for outputting or inputting electric power of the battery cells.

In some embodiments, a current collecting member may be disposed within the case, and the electrode assembly may be electrically connected to the case or an electrode terminal disposed on the case through the current collecting member.

As examples, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or other shaped battery cell, including a square-case battery cell, a blade-shaped battery cell, a polygonal-prismatic battery cell, such as a hexagonal-prismatic battery cell, or the like.

Reference to a battery in accordance with an embodiment of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity.

In some embodiments, the battery may be a battery module, and when there are a plurality of battery cells, the plurality of battery cells are arranged and fixed to form one battery module.

In some embodiments, the battery may be a battery pack including a case and a battery cell, the battery cell or battery module being housed in the case.

In some embodiments, the tank may be part of the chassis structure of the vehicle. For example, a portion of the tank may become at least a portion of the floor of the vehicle, or a portion of the tank may become at least a portion of the cross member and the side member of the vehicle.

In some embodiments, the battery may be an energy storage device. The energy storage device comprises an energy storage container, an energy storage electric cabinet and the like.

The battery cell generally includes an electrode assembly and a case, in which the electrode assembly is received. The electrode assembly includes a positive electrode and a negative electrode. During the charge and discharge of the battery cell, active ions (e.g., lithium ions) are inserted and extracted back and forth between the positive electrode and the negative electrode. In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode, which may function to prevent the positive electrode and the negative electrode from being shorted, while allowing the active ions to pass through.

The case is used to encapsulate the electrode assembly, the electrolyte, and the like. The shell can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), an aluminum-plastic film or the like.

In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector. The negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.

In the preparation of a pole piece (either positive or negative), it is often necessary to cut (e.g., a tab die cut process) to the desired size and shape. In addition, during the preparation process of forming the electrode assembly by the pole pieces, the pole lugs or metal wires generated in the cutting process from the outside are easy to fall between the pole pieces, and the burrs and the metal wires can conduct the positive electrode and the negative electrode in the charging and discharging process of the battery cells, so that the short circuit risk is caused, and the reliability of the battery cells is affected.

Based on the technical problems, the application provides a technical scheme that the insulating piece is arranged on the pole piece to prevent burrs or metal wires from overlapping the pole pieces with opposite polarities, so that the risk that the burrs conduct the pole pieces with opposite polarities is reduced, and the reliability of the battery cell is improved.

The technical solution described in the embodiments of the present application is applicable to a battery and an electric device using the battery, for example, an electric device such as a mobile phone, a portable device, a notebook computer, an electric car, an electric automobile, a ship, a spacecraft, an electric toy, and an electric tool, etc., wherein the spacecraft is an airplane, a rocket, a space plane, a spacecraft, etc., the electric toy includes a fixed or mobile electric toy, for example, a game console, an electric car toy, an electric ship toy, an electric plane toy, etc., and the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool, and a railway electric tool, for example, an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator, and an electric planer.

For convenience of explanation, the following examples will be described taking an electric device as an example of a vehicle.

Fig. 1 is a schematic structural diagram of a vehicle according to some embodiments of the present application.

As shown in fig. 1, the interior of the vehicle 1 is provided with a battery 2, and the battery 2 may be provided at the bottom or at the head or at the tail of the vehicle 1. The battery 2 may be used for power supply of the vehicle 1, for example, the battery 2 may serve as an operating power source of the vehicle 1.

The vehicle 1 may further comprise a controller 3 and a motor 4, the controller 3 being arranged to control the battery 2 to power the motor 4, for example for operating power requirements during start-up, navigation and driving of the vehicle 1.

In some embodiments of the application, the battery 2 may not only serve as an operating power source for the vehicle 1, but also as a driving power source for the vehicle 1, instead of or in part instead of fuel oil or natural gas, to provide driving power for the vehicle 1.

Fig. 2 is an exploded view of a battery according to some embodiments of the present application. As shown in fig. 2, the battery 2 includes a case 5 and a battery cell 6, and the battery cell 6 is accommodated in the case 5.

The case 5 is for accommodating the battery cell 6, and the case 5 may have various structures. In some embodiments, the case 5 may include a first case portion 5a and a second case portion 5b, the first case portion 5a and the second case portion 5b being overlapped with each other, the first case portion 5a and the second case portion 5b together defining an accommodating space 5c for accommodating the battery cell. The second housing part 5b may have a hollow structure with one end opened, the first housing part 5a has a plate-like structure, the first housing part 5a is covered on the opening side of the second housing part 5b to form the housing 5 having the accommodation space 5c, the first housing part 5a and the second housing part 5b may each have a hollow structure with one side opened, and the opening side of the first housing part 5a is covered on the opening side of the second housing part 5b to form the housing 5 having the accommodation space 5c. Of course, the first and second case portions 5a and 5b may be of various shapes, such as a cylinder, a rectangular parallelepiped, or the like.

In order to improve the sealing property after the first casing part 5a and the second casing part 5b are connected, a sealing member, such as a sealant, a seal ring, or the like, may be provided between the first casing part 5a and the second casing part 5 b.

Assuming that the first housing part 5a is covered on top of the second housing part 5b, the first housing part 5a may also be referred to as an upper case cover, and the second housing part 5b may also be referred to as a lower case.

In the battery 2, the number of the battery cells 6 may be one or more. If the number of the battery cells 6 is plural, the plurality of battery cells 6 may be connected in series or parallel or a series-parallel connection, and the series-parallel connection refers to that the plurality of battery cells 6 are connected in series or parallel. The battery units 6 can be directly connected in series or parallel or in series-parallel, and then the whole formed by the battery units 6 is accommodated in the box 5, or of course, the battery units can be connected in series or parallel or in series-parallel to form a battery module, and the battery modules are connected in series or parallel or in series-parallel to form a whole and are accommodated in the box 5.

The battery cell may be, for example, the smallest unit constituting the battery.

Fig. 3 is an exploded view of a battery cell according to some embodiments of the present application.

As shown in fig. 3, in some embodiments, the battery cell 6 includes a case 200 and an electrode assembly 100 accommodated in the case 200.

The electrode assembly 100 includes a positive electrode and a negative electrode. During charge and discharge of the battery cell 6, active ions (e.g., lithium ions) are inserted and extracted back and forth between the positive electrode and the negative electrode. Optionally, the electrode assembly 100 further includes a separator 40 disposed between the positive and negative electrodes, and the separator 40 may reduce the risk of shorting the positive and negative electrodes while allowing the passage of active ions.

The case 200 is used to encapsulate the electrode assembly 100, electrolyte, and the like. The housing 200 may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., copper aluminum composite housing 200), or an aluminum plastic film.

Fig. 4 is a schematic top view of an electrode assembly according to some embodiments of the present application. Fig. 5 is a schematic view in partial cross-section taken along the direction A-A of fig. 4. Fig. 6 is an enlarged schematic view of the block P in fig. 5. Fig. 7 is a schematic view of an electrode assembly according to some embodiments of the present application in a flattened state after a first electrode tab and an insulator are connected. Fig. 8 is a schematic partial cross-sectional view of fig. 7 taken along the direction B-B. Fig. 9 is a schematic view in partial cross-section taken along the direction B-B of fig. 7.

Referring to fig. 4 and 5, an electrode assembly 100 according to an embodiment of the present application includes first and second electrode sheets 10 and 20 having opposite polarities.

Illustratively, one of the first and second pole pieces 10, 20 is a positive pole piece, and the other is a negative pole piece.

In some embodiments, the positive electrode sheet may include a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector.

As an example, the positive electrode current collector has two surfaces opposing in its own thickness direction, and the positive electrode active material layer is provided on either one or both of the two surfaces opposing the positive electrode current collector.

As an example, the positive electrode current collector may employ carbon, a metal foil, or a composite current collector. For example, stainless steel, copper, aluminum, nickel, carbon electrodes, nickel, titanium, silver-surface-treated aluminum, stainless steel, or the like can be used as the metal foil. The composite current collector may include a polymeric material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a polymer material substrate (e.g., a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

As an example, the positive electrode active material layer includes a positive electrode active material, which may include at least one of lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. Other conventional materials that can be used as a battery positive electrode active material layer can also be used as the positive electrode active material. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO ₄ (which may also be referred to simply as LFP)), a composite of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO ₄), a composite of lithium manganese phosphate and carbon, lithium manganese iron phosphate, a composite of lithium manganese iron phosphate and carbon. Examples of lithium transition metal oxides may include, but are not limited to, at least one of lithium cobalt oxide (e.g., liCoO ₂), lithium nickel oxide (e.g., liNiO ₂), lithium manganese oxide (e.g., liMnO ₂、LiMn₂O₄), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., liNi _1/3Co_{1/ 3}Mn_1/3O₂ (which may also be abbreviated as NCM ₃₃₃)、LiNi_0.5Co_0.2Mn_0.3O₂ (which may also be abbreviated as NCM 523), liNi _0.5Co_0.25Mn_0.25O₂ (which may also be abbreviated as NCM 211), liNi _0.6Co_0.2Mn_0.2O₂ (which may also be abbreviated as NCM 622), liNi _0.8Co_0.1Mn_0.1O₂ (which may also be abbreviated as NCM 811), lithium nickel cobalt aluminum oxide (e.g., liNi _0.80Co_0.15Al_0.05O₂), and modified compounds thereof, and the like.

In some embodiments, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.

As an example, the negative electrode current collector may employ a metal foil, a foam metal, or a composite current collector. For example, as the metal foil, silver-surface-treated aluminum or stainless steel, copper, aluminum, nickel, carbon electrode, nickel or titanium, or the like can be used. The foam metal can be foam nickel, foam copper, foam aluminum, foam alloy, foam carbon or the like. The composite current collector may include a polymeric material base layer and a metal layer. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a polymer material substrate (e.g., a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

As an example, the anode active material layer includes an anode active material. The negative electrode active material may employ a negative electrode active material for a battery cell, which is well known in the art. As an example, the anode active material may include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, lithium titanate, and the like. The silicon-based material may include at least one of elemental silicon, silicon oxygen compounds, silicon carbon composites, silicon nitrogen composites, and silicon alloys. The tin-based material may include at least one of elemental tin, a tin oxide, and a tin alloy. The anode active material of the present application may also use other conventional materials that can be used as anode active materials for batteries. These negative electrode active materials may be used alone or in combination of two or more.

In some embodiments, the material of the positive electrode current collector may be aluminum and the material of the negative electrode current collector may be copper.

In some embodiments, the electrode assembly 100 is a rolled structure. Illustratively, the first pole piece 10 and the second pole piece 20 are each of a ribbon-like structure, and the first pole piece 10, the separator 40, and the second pole piece 20 are wound into a wound structure.

In some embodiments, electrode assembly 100 is a lamination stack.

As an example, a plurality of first and second pole pieces 10, 20 may be provided, respectively, and a plurality of first pole pieces 10 and a plurality of second pole pieces 20 may be alternately stacked.

As an example, the first pole piece 10 may be provided in plurality, and the second pole piece 20 is folded to form a plurality of folded sections arranged in a stacked manner, and one first pole piece 10 is sandwiched between adjacent folded sections.

As an example, the first pole piece 10 and the second pole piece 20 are each folded to form a plurality of folded sections in a stacked arrangement.

As an example, the spacers 40 may be provided in plurality, respectively between any adjacent first pole piece 10 or second pole piece 20.

As an example, the separator 40 may be continuously disposed between any adjacent first pole piece 10 or second pole piece 20 by folding or winding.

In some embodiments, the electrode assembly 100 may have a cylindrical shape, a flat shape, a polygonal column shape, or the like.

Referring to fig. 4 to 6, an electrode assembly 100 according to an embodiment of the present application includes a first electrode sheet 10 and a second electrode sheet 20 with opposite polarities.

The first electrode sheet 10 includes a first current collecting body 11 and a first active material layer 12 disposed on a surface of the first current collecting body 11.

The first current collecting body 11 includes two first surfaces disposed opposite to each other in the thickness direction X thereof, and may have the first active material layer 12 disposed on one of the first surfaces or may have the first active material layer 12 disposed on both of the first surfaces. The first active material layer 12 may be integrally provided on the first surface. Alternatively, a portion of the first active material layer 12 may be disposed at other locations, for example, the first electrode sheet 10 further includes a first tab 113a connected to the first current collecting body 11, and a portion of the first active material layer 12 may be disposed at a root portion of the first tab 113a near the first current collecting body 11.

In some examples, the first pole piece 10 is a positive pole piece and the second pole piece 20 is a negative pole piece. In other examples, the first electrode sheet 10 is a negative electrode sheet and the second electrode sheet 20 is a positive electrode sheet.

In some embodiments, referring to fig. 5, the first active material layer 12 includes a body region 121 and a thinned region 122, the thinned region 122 is located at one side of the body region 121 along the first direction Y, and at least a portion of the thinned region 122 has a thickness smaller than that of the body region 121. The first direction Y is perpendicular to the thickness direction X of the first current collecting body 11.

Illustratively, an end of thinned region 122 proximate body region 121 is directly connected to body region 121. In some examples, the thickness of the end of thinned region 122 near body region 121 is less than the thickness of the end of body region 121 near thinned region 122, and the junction of thinned region 122 and body region 121 forms a step. In other examples, the thickness of the end of thinned region 122 adjacent body region 121 is equal to the thickness of the end of body region 121 adjacent thinned region 122.

Illustratively, body region 121 is a generally uniform thickness structure. The average thickness of the thinned region 122 is smaller than the thickness of the body region 121.

In some embodiments, referring to fig. 5, the electrode assembly 100 further includes an insulating member 30, and at least a portion of the insulating member 30 is disposed between the first and second electrode sheets 10 and 20 in the thickness direction X. And the insulator 30 is disposed on one side of the first active material layer 12 in the first direction Y.

Illustratively, at least a portion of the first end face 111 overlaps the insulator 30 in the thickness direction X of the first current collecting body 11. In the first direction Y, both ends of the insulator 30 are located on both sides of the first end face 111, respectively.

The number of the insulating members 30 may be one or more.

In some embodiments, referring to fig. 5 and 6, the insulating member 30 is connected to the surface of the thinned region 122 facing away from the first current collecting body 11, and the surface of the insulating member 30 facing away from the first current collecting body 11 does not exceed the surface of the body region 121 facing away from the first current collecting body 11 in the direction in which the first current collecting body 11 faces toward the first active material layer 12.

In some examples, insulator 30 is attached to the entire surface of thinned region 122 facing away from first current collecting body 11. In other examples, insulator 30 is attached to a portion of the surface of thinned region 122 facing away from first current collecting body 11.

Illustratively, the distance between the surface of insulator 30 facing away from first current collecting body 11 and first current collecting body 11 is less than or equal to the distance between the surface of body region 121 facing away from first current collecting body 11 and first current collecting body 11. In some examples, at least a portion of the surface of insulator 30 facing away from first current collector body 11 is disposed flush with the surface of body region 121 facing away from the first current collector. In other examples, the surface of the body region 121 facing away from the first current collector is disposed to protrude from the surface of the insulating member 30 facing away from the first current collector body 11 in a direction in which the first current collector body 11 is directed toward the first active material layer 12.

In the electrode assembly 100 provided by the embodiment of the application, the insulating member 30 is at least partially arranged between the first pole piece 10 and the second pole piece 20, so that metal burrs can be prevented from conducting the first pole piece 10 and the second pole piece 20, and the possibility of thermal runaway caused by short circuit is reduced. Advantageously, the connection strength of the connection between the insulating member 30 and the first electrode sheet 10 can be increased, the possibility of an increase in the overall thickness of the electrode assembly 100 is reduced, the thickness difference between the middle region and the end region of the electrode assembly 100 is reduced, the risk of winding dislocation caused by inconsistent tension of the electrode assembly 100 at both ends of the electrode assembly 100 along the first direction Y during the winding process is reduced, and the reliability of the battery cell 6 is improved.

In some alternative embodiments, referring to fig. 5 and 6, the insulating member 30 includes a first insulating portion 31, the first insulating portion 31 including a first portion 311 and a second portion 312, the second portion 312 being located at an end of the first portion 311 near the body region 121, the second portion 312 having a thickness less than a thickness of the first portion 311.

Illustratively, the first insulating portion 31 includes a first end, a second end, and an intermediate section therebetween, the second portion 312 is the first end, the first portion 311 is the second end and the intermediate section, the first end is an end of the first insulating portion 31 proximate to the body region 121, and the second end is an end of the first insulating portion 31 facing away from the body region 121. In some examples, the thickness of the first end is less than the thickness of the second end, and the thickness of the first end is less than the thickness of the intermediate section. In other examples, the thickness of the first end is only less than the thickness of the second end. In other examples, the thickness of the first end is less than the thickness of the intermediate section.

Through the above arrangement, it is advantageous to increase the process error of the insulating member 30, reduce the possibility that the first insulating portion 31 protrudes from the body region 121 due to the excessively thick thickness of the first insulating portion 31 itself and under the influence of the process error, and further reduce the thickness difference between the middle region and the end region of the electrode assembly 100.

In some alternative embodiments, referring to fig. 5 and 6, the thickness of thinned region 122 gradually decreases in a direction from body region 121 toward thinned region 122.

Illustratively, the thickness of the end of the thinned region 122 near the body region 121 may be equal to the thickness of the body region 121, and the thickness of the end of the thinned region 122 away from the body region 121 may be a predetermined value or may be zero.

In these alternative embodiments, the above arrangement is beneficial to reducing the difficulty in manufacturing the thinned region 122, reducing the manufacturing accuracy of the thinned region 122, and improving the production efficiency.

In some alternative embodiments, referring to fig. 5 and 6, the insulating member 30 includes a first insulating portion 31, the first insulating portion 31 is connected to a surface of the thinning region 122 facing away from the first current collecting body 11, and the thickness of the first insulating portion 31 gradually increases in a direction from the body region 121 toward the thinning region 122.

Illustratively, the thickness of the first insulating portion 31 may be gradually increased stepwise or may be smoothly increased.

In these alternative embodiments, through the above arrangement, it is advantageous to increase the process error of the insulator 30, reducing the likelihood that the insulator 30 will increase the overall thickness of the first pole piece 10.

In other examples, the first insulating portion 31 includes two portions, one portion of the first insulating portion 31 having a thickness gradually increasing in a direction of the body region 121 toward the thinned region 122 and the other portion of the first insulating portion 31 having a thickness that is uniform. Alternatively, a portion of the first insulating portion 31 having a gradually increasing thickness is located on a side of the other portion of the first insulating portion 31 near the body region 121.

In some alternative embodiments, referring to fig. 5 to 8, the insulating member 30 includes a first insulating portion 31 and a second insulating portion 32, and the first insulating portion 31 is connected to a surface of the thinned region 122 facing away from the first current collecting body 11. The first current collecting body 11 includes a coated region 112 and an uncoated region 113 disposed along the first direction Y, and the second insulating part 32 is disposed at the uncoated region 113.

The first current collecting body 11 includes a coated region 112 and an uncoated region 113, in other words, the surface of the coated region 112 is coated with the first active material layer 12, and the surface of the uncoated region 113 is not coated with the first active material layer 12. The first insulating portion 31 is connected to a surface of the thinned region 122 facing away from the first current collecting body 11, and in some examples, an orthographic projection of at least a portion of the first insulating portion 31 onto the first current collecting body 11 falls within the coating region 112.

Alternatively, the first insulating part 31 and the second insulating part 32 may be a unitary structure, and the first insulating part 31 extends from the coated region 112 to the uncoated region 113 to be connected with the second insulating part 32.

Alternatively, the first insulating portion 31 and the second insulating portion 32 may be of a separate structure, and the first insulating portion 31 and the second insulating portion 32 may be connected by bonding or the like.

In some examples, the second insulation 32 is disposed at the uncoated region 113, and the second insulation 32 may cover the entire surface of the uncoated region 113. In other examples, the second insulating portion 32 may cover a portion of the surface of the uncoated region 113.

In these alternative embodiments, the above arrangement is advantageous to increase the blocking area of the insulating member 30 to the first pole piece 10, further reducing the possibility of metal burrs conducting the first pole piece 10 and the second pole piece 20.

In some alternative embodiments, referring to fig. 7 to 9, one end of the first current collecting body 11 in the first direction Y has a first end surface 111, and the second insulating portion 32 extends from one end of the first insulating portion 31 in the first direction Y and is disposed to cover the first end surface 111.

Illustratively, the first current collecting body 11 has a small thickness, the first end surface 111 is small in size in the thickness direction X of the first current collecting body 11, and the first end surface 111 may be approximated as a line.

Illustratively, at least a portion of the first end face 111 is formed during the cutting process of the first pole piece 10.

Illustratively, the first end face 111 connects the two first surfaces.

In some examples, the projection of the first insulating portion 31 is located within the projection of the first pole piece 10 in the thickness direction X, and the projection of the second insulating portion 32 does not overlap with the projection of the first pole piece 10. In other examples, in the thickness direction X, the projection of the first insulating portion 31 is located within the projection of the first pole piece 10, a portion of the projection of the second insulating portion 32 overlaps the projection of the first pole piece 10, and another portion of the projection of the second insulating portion 32 does not overlap the projection of the first pole piece 10.

In these alternative embodiments, by the above arrangement, the connection area of the insulating member 30 and the first pole piece 10 is further increased, the connection strength of the insulating member 30 and the first pole piece 10 is improved, and the possibility that burrs on the first end face 111 of the first current collecting body 11 conduct the first pole piece 10 and the second pole piece 20 is reduced.

In some alternative embodiments, referring to fig. 7 and 8, a side surface of the thinned region 122 facing away from the main body region 121 in the first direction Y is a second end surface 122a, the first end surface 111 and the second end surface 122a are disposed flush, and the second insulating portion 32 covers the first end surface 111 and the second end surface 122a. According to the embodiment of the application, the difference between the sizes of the first current collecting main body 11 and the first active material layer 12 along the first direction Y can be reduced, the waste of the first current collecting main body 11 is reduced, the energy density is improved, the connection area of the second insulating part 32 and the first pole piece 10 is increased, the risk that the insulating part 30 falls off from the first pole piece 10 is reduced, and the reliability is improved.

In some alternative embodiments, referring to fig. 5 to 7, the uncoated region 113 includes a hollow foil region 113b and a first tab 113a, the first tab 113a protrudes from the hollow foil region 113b, and a portion of the insulating member 30 is disposed on a surface of the first tab 113 a.

Illustratively, as shown in fig. 7, the first pole piece 10 may be a flat surface in a belt shape in the flattened state, the empty foil region 113b may be located at one end of the coating region 112 in the first direction Y, and the extension length of the empty foil region 113b may be equal to the extension length of the first pole piece 10. The first tabs 113a may be located at a side of the empty foil region 113b opposite to the coating region 112, and the number of the first tabs 113a may be plural, where the plural first tabs 113a are disposed at intervals along the extending direction of the first pole piece 10.

Alternatively, the first tab 113a may include a first wall surface disposed opposite to each other in the thickness direction X and a second wall surface located between the two first wall surfaces, and in some examples, the insulator 30 covers at least part of the first wall surfaces and at least part of the second avoidance. In other examples, the insulator 30 covers at least a portion of the first wall. In other examples, the insulator 30 covers at least a portion of the second wall.

Alternatively, the end of the blank foil region 113b facing away from the coating region 112 forms a first end face 111, and the first tab 113a protrudes from the first end face 111.

In these alternative embodiments, by providing the hollow foil region 113b, the connection area of the insulating member 30 and the first pole piece 10 is increased, the connection difficulty of the insulating member 30 and the first pole piece 10 is increased, the risk that the first pole piece 10 cuts into the first active material layer 12 during the cutting process is reduced, and the waste of active materials is reduced. By disposing a part of the insulating member 30 on the surface of the first tab 113a, the possibility that burrs formed at the cut edge of the first tab 113a conduct the first and second electrode tabs 10 and 20 is reduced, and the reliability of the battery cell is further improved.

In some alternative embodiments, referring to fig. 7 and 9, the second insulating portion 32 completely covers the uncoated region 113, so as to reduce the possibility of the uncoated region being conducted with the second pole piece 20, reduce the risk of short-circuiting, and improve the reliability.

In some alternative embodiments, referring to fig. 7-9, the minimum thickness of the second insulating portion 32 is greater than the minimum thickness of the first insulating portion 31.

As can be seen from the foregoing, the thickness of the first insulating portion 31 gradually increases along the direction of the main body region 121 toward the thinned region 122, the first insulating portion 31 may include a maximum thickness and a minimum thickness, and the minimum thickness of the second insulating portion 32 may be the thickness of the uniform film layer of the second insulating portion 32.

In some alternative embodiments, referring to fig. 7 to 9, the first active material layer 12 is disposed on both side surfaces of the first current collecting body 11, and the insulating members 30 are disposed on both sides of the first current collecting body 11, and the two insulating members 30 are connected.

Illustratively, the first active material layer 12 is disposed on both sides of the first current collecting body 11, one insulating member 30 is disposed on both sides of the first current collecting body 11, and the two insulating members 30 each include a first insulating portion 31 and a second insulating portion 32, and the shapes of the two first insulating portions 31 may be the same or different. The projections of the two first insulating portions 31 in the thickness direction X may overlap or may be partially overlapped. At least part of the two second insulating portions 32 are disposed in abutment.

By providing two insulators 30 and connecting the second insulating portions 32 of the two insulators 30, the connection area of the insulators 30 and the first pole piece 10 can be increased, and the risk of the insulators 30 falling off can be reduced. The second insulation 32 may separate burrs on the first end face 111 from the second pole piece 20, thereby reducing the risk of short circuits.

In some alternative embodiments, the porosity of the insulation is 30% -40%. The insulator has a high porosity to reduce resistance to ions passing through the insulator.

Illustratively, the insulator has a porosity of 30%, 32%, 34%, 35%, 36%, 38%, or 40%.

Alternatively, as can be seen from the foregoing, the insulator may include a first insulator portion having a porosity of 30% -40%.

In some embodiments, the porosity of the insulation is less than the porosity of the separator. Compared with the isolating piece, the insulating piece is not easy to shrink, so that the insulating effect is improved.

Illustratively, the porosity of the insulation has a meaning well known in the art, and can be measured using known methods. For example, the tests may all be performed with reference to standard GB/T36363-2018.

In some alternative embodiments, referring to fig. 4 and 5, the electrode assembly 100 further includes a separator 40 for separating the first and second pole pieces 10, 20. In the first direction Y, the insulating member 30 does not protrude beyond the spacer 40, thereby reducing the space that the insulating member 30 additionally occupies in the first direction Y.

The insulator 30 can also support the spacer 40 from the inside, reducing the risk of the spacer wrinkling and kinking.

In some embodiments, the first pole piece 10, the separator 40, and the second pole piece 20 are wound. In the winding direction V, both ends of the insulator 30 do not exceed the separator 40.

Illustratively, as shown in fig. 4, the positive direction of the winding direction V is counterclockwise and the negative direction of the winding direction V is clockwise. The insulator 30 does not protrude beyond the trailing end of the separator 40 in the positive direction of the winding direction V, and the insulator 30 does not protrude beyond the leading end of the separator 40 in the negative direction of the winding direction V.

The spacer may bind the insulator 30, maintain the fit of the insulator to the first pole piece 10, and reduce the risk of the insulator 30 falling off the first pole piece 10.

According to some embodiments of the present application, there is also provided a battery including a plurality of the battery cells of any of the above embodiments.

According to some embodiments of the present application, the present application further provides an electric device, including the battery cell of any one of the above embodiments, where the battery cell is configured to provide electric energy for the electric device. The electrical device may be any of the aforementioned devices or systems that employ a battery cell.

Referring to fig. 4 to 9, according to some embodiments of the present application, a battery cell 6 includes a case 200 and an electrode assembly 100 accommodated in the case 200, the electrode assembly 100 including a first electrode tab 10 and a second electrode tab 20 having opposite polarities, the first electrode tab 10 including a first current collecting body 11 and a first active material layer 12 disposed on a surface of the first current collecting body 11, the first active material layer 12 including a body region 121 and a reduced thickness region 122, at least a portion of the reduced thickness region 122 having a thickness smaller than that of the body region 121, the reduced thickness region 122 being located at one side of the body region 121 in a first direction Y. The electrode assembly 100 further includes an insulating member 30 at least a portion of which is disposed between the first electrode sheet 10 and the second electrode sheet 20 and on one side of the first active material layer 12 in the first direction Y, wherein the insulating member 30 includes a first insulating portion 31, the first insulating portion 31 is connected to a surface of the thinned region 122 facing away from the first current collecting body 11, and the first insulating portion 31 does not protrude beyond a surface of the body region 121 facing away from the first current collecting body 11 in a direction in which the first current collecting body 11 points toward the first active material layer 12.

The insulator 30 includes a first insulator portion 31 and a second insulator portion 32, the first insulator portion 31 being connected to a surface of the thinned region 122 facing away from the first current collecting body 11. The first current collecting body 11 includes a coated region 112 and an uncoated region disposed along the first direction Y, and the second insulating part 32 is disposed at the uncoated region 113. The uncoated region 112 includes an empty foil region 113b and a first tab 113a, the first tab 113a protrudes from the empty foil region 113b, and a part of the insulator 30 is disposed on the surface of the first tab 113 a.

The thickness of the thinned region gradually thins in the direction from the body region 121 toward the thinned region 122, and the thickness of the first insulating portion 31 gradually increases. The first current collecting body 11 is provided with the first active material layer 12 on both sides thereof, and the insulating member 30 further includes a second insulating portion 32 having a first end surface 111 at one end of the first current collecting body 11 in the first direction Y, the second insulating portion extending from one end of the first insulating portion 31 in the first direction Y beyond the first end surface 111. The insulator 30 is provided on both sides of the first current collecting body 11, and the second insulation portions 32 of the two insulators 30 are connected. The porosity of the first insulating portion 31 is 30% -40%.

It should be noted that the above embodiments are only used to illustrate the technical solution of the present application, but not to limit the technical solution of the present application, and although the detailed description of the present application is given with reference to the above embodiments, it should be understood by those skilled in the art that the technical solution described in the above embodiments may be modified or some or all technical features may be equivalently replaced, and these modifications or substitutions do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present application, and all the modifications or substitutions are included in the scope of the claims and the specification of the present application. In particular, the technical features mentioned in the respective embodiments may be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions falling within the scope of the claims.

Claims (15)

1. A battery cell comprising a housing and an electrode assembly contained within the housing, the electrode assembly comprising first and second electrode sheets of opposite polarity;

The first pole piece comprises a first current collecting main body and a first active material layer arranged on the surface of the first current collecting main body, the first active material layer comprises a main body area and a thinning area, the thickness of at least part of the thinning area is smaller than that of the main body area, the thinning area is positioned on one side of the main body area along a first direction, and the first direction is perpendicular to the thickness direction of the first current collecting main body;

the electrode assembly further comprises an insulating member, at least part of the insulating member is arranged between the first pole piece and the second pole piece, the insulating member is connected to the surface of the thinning area, which is away from the first current collecting main body, along the direction that the first current collecting main body points to the first active material layer, the surface of the insulating member, which is away from the first current collecting main body, does not exceed the surface of the main body area, which is away from the first current collecting main body.

2. The battery cell of claim 1, wherein the insulator comprises a first insulator portion comprising a first portion and a second portion, the second portion being located at an end of the first portion proximate the body region, the second portion having a thickness less than a thickness of the first portion.

3. The battery cell of claim 1, wherein the thickness of the thinned region tapers in a direction from the body region toward the thinned region.

4. The battery cell of claim 3, wherein the insulator includes a first insulator portion connected to a surface of the thinned region facing away from the first current collecting body, the first insulator portion having a thickness that gradually increases in a direction from the body region toward the thinned region.

5. The battery cell of claim 1, wherein the insulator comprises a first insulator and a second insulator, the first insulator being connected to a surface of the thinned region facing away from the first current collecting body;

The first current collecting body includes a coated region and an uncoated region disposed along the first direction, and the second insulating portion is disposed at the uncoated region.

6. The battery cell according to claim 5, wherein one end of the first current collecting body in the first direction has a first end face, and the second insulating portion extends from one end of the first insulating portion in the first direction and is disposed so as to cover the first end face.

7. The battery cell as recited in claim 6, wherein a side surface of the thinned region facing away from the body region in the first direction is a second end surface, the first end surface and the second end surface are disposed flush, and the second insulating portion covers the first end surface and the second end surface.

8. The battery cell of claim 5, wherein the uncoated region comprises an empty foil region and a first tab, the first tab protruding from the empty foil region, and a portion of the insulator being disposed on a surface of the first tab.

9. The battery cell of claim 8, wherein the second insulating portion completely covers the empty foil region.

10. The battery cell of claim 5, wherein the minimum thickness of the second insulating portion is greater than the minimum thickness of the first insulating portion.

11. The battery cell according to claim 1, wherein the first active material layer is provided on both side surfaces of the first current collecting body, the insulating member is provided on both sides of the first current collecting body, and the two insulating members are connected.

12. The battery cell of claim 1, wherein the insulator has a porosity of 30% -40%.

13. The battery cell of claim 1, wherein the electrode assembly further comprises a separator for separating the first and second pole pieces;

in the first direction, the insulator does not extend beyond the spacer.

14. A battery comprising a cell according to any one of claims 1 to 13.

15. An electrical device comprising a battery as claimed in claim 14 for providing electrical energy.