CN217788485U - Electrode assembly, battery monomer, battery and consumer - Google Patents

Abstract

The application provides an electrode subassembly, battery monomer, battery and consumer relates to the battery field. The electrode assembly includes a first pole piece, a second pole piece, and a third pole piece. The polarity of the first pole piece is opposite to that of the second pole piece, and the first pole piece and the second pole piece are wound or laminated to form the main body part. The first pole piece comprises a tail part positioned at the outermost layer of the main body part. The third pole piece is opposite to the first pole piece in polarity, and an active material layer is arranged on one side of the third pole piece. The active material layer is disposed at least partially opposite the ending portion. Through setting up the third pole piece, the polarity that only unilateral of third pole piece was provided with active substance layer and with first pole piece is opposite, and the active substance layer of third pole piece is at least partially relative with the outermost active substance layer of main part, makes metal ion can move between third pole piece and first pole piece and produce or store the electric energy. The utilization rate of the active material layer on the outermost layer of the main body part can be improved, the utilization rate of the electrode assembly can be improved, and the energy density of the battery monomer can be improved.

Description

Electrode assembly, battery monomer, battery and consumer

Technical Field

The application relates to the field of batteries, in particular to an electrode assembly, a battery monomer, a battery and electric equipment.

Background

Batteries are widely applied in the field of new energy resources, such as electric vehicles, new energy vehicles and the like, and the new energy vehicles and the electric vehicles become new development trends of the automobile industry. The electrode assembly is a part of the battery cell in which electrochemical reactions occur, and the utilization rate of the electrode assembly affects the energy density of the battery cell. However, the utilization rate of the electrode assembly in the prior art is not high, which is not favorable for improving the energy density of the battery.

SUMMERY OF THE UTILITY MODEL

An object of the embodiment of the application is to provide an electrode assembly, a battery cell, a battery and an electric device, which aim to solve the problems that the utilization rate of the electrode assembly is not high and the improvement of the energy density of the battery is not facilitated in the prior art.

In a first aspect, an embodiment of the present application provides an electrode assembly, where the electrode assembly includes a first pole piece, a second pole piece, and a third pole piece, where polarities of the first pole piece and the second pole piece are opposite, the first pole piece and the second pole piece are wound or stacked to form a main body portion, and the first pole piece includes a tail portion located at an outermost layer of the main body portion; the polarity of the third pole piece is opposite to that of the first pole piece, an active substance layer is arranged on one side of the third pole piece, and the active substance layer and the ending part are at least partially arranged oppositely.

In the above technical solution, the electrode assembly is provided with the third pole piece, only one side of the third pole piece is provided with the active material layer, and the polarity of the third pole piece is opposite to that of the first pole piece, and the active material layer of the third pole piece is at least partially arranged opposite to the active material layer on the outermost layer of the main body portion, so that the metal ions can move between the third pole piece and the first pole piece to generate or store electric energy. Therefore, the utilization rate of the active material layer on the outermost layer of the main body part can be improved, the utilization rate of the electrode assembly is improved, and the energy density of the battery cell is improved.

As an optional solution of the embodiment of the present application, the electrode assembly includes a winding member, the third electrode sheet is disposed on the winding member, and the winding member is wound on the outer side of the main body portion, so that the active material layer and the ending portion are at least partially disposed opposite to each other.

In above-mentioned technical scheme, twine in the outside of main part through the winding to play the fixed action to the main part, avoid the main part not hard up or loose the frame. In addition, set up the third pole piece in the winding for the winding is when the winding main part, spacing third pole piece and main part, guarantee that the third pole piece can be relative with final phase portion at least part, avoids the off tracking of third pole piece when putting into the casing with electrode subassembly, in order to realize the utilization to the outmost active material of main part, promotes electrode subassembly's utilization ratio, in order to promote battery monomer energy density.

As an optional solution of the embodiment of the present application, the third pole piece is disposed on an inner surface of the winding member.

In above-mentioned technical scheme, through setting up the third pole piece in the internal surface of winding, reduce the distance between third pole piece and the final phase of a project, be favorable to metal ion to remove between third pole piece and first pole piece, improve the utilization ratio to the outermost active material layer of main part.

As an optional technical scheme of the embodiment of the application, a first adhesive layer is arranged on the inner surface of the winding piece, and the tail end of the winding piece is bonded to the head end of the winding piece through the first adhesive layer.

In above-mentioned technical scheme, through setting up first glue film, the winding piece head and the tail of being convenient for bonds, reduces the probability of winding piece head and the tail separation, promotes the spacing effect of winding piece to main part and third pole piece.

As an optional technical solution of the embodiment of the present application, the electrode assembly further includes a first isolation film, where at least a portion of the first isolation film is disposed between the third pole piece and the tail portion to isolate the third pole piece and the tail portion in an insulating manner.

In the technical scheme, the third pole piece is insulated and isolated from the ending part by arranging the first isolation film, so that the third pole piece is prevented from being in contact with the ending part to cause short circuit.

As an optional solution of the embodiment of the present application, the first isolation film is disposed on an inner surface of the winding member and arranged along a winding direction of the winding member.

In the technical scheme, the first isolation film is arranged on the inner surface of the winding part, so that the first isolation film can be arranged between the third pole piece and the ending part when the winding part winds the main body part, simplicity and convenience are achieved, and the production efficiency of the electrode assembly is improved.

As an optional technical scheme of this application embodiment, first barrier film covers completely the internal surface, first barrier film deviates from one side of internal surface is provided with the second glue film, the tail end of first barrier film passes through the second glue film bond in the head end of winding.

In the technical scheme, the first isolation film is completely covered on the inner surface, the area of the first isolation film is large, and even if the third pole piece and the first isolation film are staggered to a certain degree, the third pole piece and the tail end part are not easy to contact, so that the insulating isolation effect of the third pole piece and the tail end part is favorably improved. Through setting up the second glue film, be convenient for bond the tail end of first barrier film in the head end of winding through the second glue film, reduce the probability of winding head and the tail separation, promote the spacing effect of winding to main part and third pole piece.

As an optional technical solution of the embodiment of the present application, along the thickness direction of the main body portion, the third pole pieces are disposed on both sides of the main body portion.

In above-mentioned technical scheme, all set up the third pole piece through the both sides at the main part, increase third pole piece and receipts afterbody total area relative further promote the utilization ratio to the outermost active material layer of main part, are favorable to improving electrode subassembly's utilization ratio, improve the free energy density of battery.

As an optional technical solution of the embodiment of the present application, the third electrode includes a first connection section, a second connection section, and a third connection section, and along the thickness direction of the main body portion, the first connection section and the second connection section are respectively disposed on two sides of the main body portion, and the third connection section is connected to the first connection section and the second connection section.

In above-mentioned technical scheme, first linkage segment and second linkage segment all set up with ending portion relatively, and the third linkage segment probably sets up with ending portion relatively for the third pole piece has covered the outermost active material layer of the main part of most parts, and the area that the third pole piece is relative with ending portion is great, is favorable to promoting the utilization ratio to the outermost active material layer of main part, improves the free energy density of battery.

As an optional technical solution of the embodiment of the present application, the first pole piece and the second pole piece are wound to form the main body portion, and the main body portion includes a straight region and a bent region connected to the straight region; the third pole piece comprises a first connecting section, a second connecting section and a third connecting section, the first connecting section and the second connecting section are respectively arranged on two sides of the straight area along the thickness direction of the main body part, and the third connecting section is connected with the first connecting section and the second connecting section and is arranged opposite to the bending area.

In above-mentioned technical scheme, through setting up first linkage segment and second linkage segment respectively in the both sides in straight district, the third linkage segment is relative with the district of buckling for the third pole piece has covered the most outermost active material layer of main part of half, and the third pole piece is great with the relative area of receipts afterbody, is favorable to promoting the utilization ratio to the outermost active material layer of main part, improves the free energy density of battery.

As an optional technical solution of the embodiment of the present application, along the thickness direction of the main body portion, the projection of the third pole piece does not exceed the projection of the tail portion.

In above-mentioned technical scheme, the projection of third pole piece can coincide completely with the projection of receipts afterbody, like this, can also promote the outermost active material's of main part utilization ratio when can not causing the third pole piece extravagant. The projection of third pole piece can also be located and receive the projection of afterbody, like this, also can promote the outmost active material's of main part utilization ratio to a certain extent, and the third pole piece is utilized completely simultaneously, can not cause the third pole piece extravagant.

In a second aspect, embodiments of the present application further provide a battery cell, where the battery cell includes a case and the electrode assembly in any one of the above cases, where the electrode assembly is accommodated in the case.

In a third aspect, an embodiment of the present application further provides a battery, where the battery includes a box body and the above battery cell, and the battery cell is accommodated in the box body.

In a fourth aspect, an embodiment of the present application further provides an electric device, where the electric device includes the above battery, and the battery is used to provide electric energy.

Drawings

To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.

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 provided by some embodiments of the present application;

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

FIG. 4 is a schematic structural view of an electrode assembly provided in accordance with some embodiments of the present application;

FIG. 5 is a schematic view of an electrode assembly provided in some embodiments of the present application (with the addition of a winding member in addition to FIG. 4);

FIG. 6 is a schematic diagram of a connection of a winding to a third pole piece provided by some embodiments of the present application;

FIG. 7 is a schematic top view of a wrapping coupled to a third pole piece provided by some embodiments of the present application;

FIG. 8 is a schematic structural view of an electrode assembly (a first separator film attached to a wrapping) provided in accordance with certain embodiments of the present disclosure;

fig. 9 is a schematic diagram of a connection of a winding member, a third pole piece and a first isolation film according to some embodiments of the present disclosure;

FIG. 10 is a schematic top view of a wrapping, a third pole piece and a first separator film according to some embodiments of the present disclosure;

fig. 11 is a schematic structural view of an electrode assembly (a first separator completely covers a winding member) according to some embodiments of the present application;

FIG. 12 is a schematic view of the connection of the wrapping, the third pole piece and the first separator film (the first separator film completely covers the wrapping) provided by some embodiments of the present application;

fig. 13 is a schematic structural view of an electrode assembly (a third electrode includes a first connection segment, a second connection segment, and a third connection segment) provided in some embodiments of the present application.

An icon: 10-a box body; 11-a first part; 12-a second part; 20-a battery cell; 21-end cap; 22-an electrode assembly; 221-a body portion; 2211-a first pole piece; 22111-receive tail; 2212-second pole piece; 2213-a second barrier film; 2214-straight area; 2215-bending zone; 222-a third pole piece; 2221-active material layer; 2222-first connecting segment; 2223-second connecting segment; 2224-third connecting segment; 223-a winding member; 2231-head end; 2232-tail end; 224-a first barrier film; 23-a housing; 100-a battery; 200-a controller; 300-a motor; 1000-vehicle.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection 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 terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "including" and "having," and any variations thereof, in the description and claims of this application and the description of the above figures are intended to cover non-exclusive inclusions. The terms "first," "second," and the like in the description and claims of this application or in the foregoing drawings are used for distinguishing between different elements and not for describing a particular sequential or chronological order.

Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the specification. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "attached" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

The term "and/or" in this application is only one kind of association relationship describing the associated object, and means that there may be three kinds of relationships, for example, a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" in this application generally indicates that the former and latter related objects are in an "or" relationship.

In the embodiments of the present application, like reference numerals denote like parts, and a detailed description of the same parts is omitted in different embodiments for the sake of brevity. It should be understood that the thickness, length, width and other dimensions of the various components in the embodiments of the present application and the overall thickness, length, width and other dimensions of the integrated device shown in the drawings are only exemplary and should not constitute any limitation to the present application.

The appearances of "a plurality" in this application are intended to mean more than two (including two).

In this application, the battery cell may include a lithium ion secondary battery cell, a lithium ion primary battery cell, a lithium sulfur battery cell, a sodium lithium ion battery cell, a sodium ion battery cell, or a magnesium ion battery cell, and the embodiment of the present application is not limited thereto. The battery cell may be a cylinder, a flat body, a rectangular parallelepiped, or other shapes, which is not limited in the embodiments of the present application. The battery cells are generally divided into three types in an encapsulation manner: the cylindrical battery cell and the square battery cell are also not limited in this application.

Reference to a battery in embodiments of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in the present application may include a battery module or a battery pack, etc. Batteries generally include a case for enclosing one or more battery cells. The box can avoid liquid or other foreign matters to influence the charging or discharging of battery monomer.

The battery monomer comprises an electrode assembly and electrolyte, wherein the electrode assembly comprises a positive electrode plate, a negative electrode plate and a separation film. The battery cell mainly depends on metal ions to move between the positive pole piece and the negative pole piece to work. The positive pole piece includes anodal mass flow body and anodal active substance layer, and anodal active substance layer coats in anodal mass flow body's surface, and the anodal mass flow body protrusion in the anodal mass flow body that has coated anodal active substance layer of uncoated anodal active substance layer, and the anodal mass flow body that does not coat anodal active substance layer is as anodal utmost point ear. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, or the like. The negative pole piece includes negative pole mass flow body and negative pole active substance layer, and the negative pole active substance layer coats in the surface of negative pole mass flow body, and the negative pole mass flow body protrusion in the negative pole mass flow body of coating the negative pole active substance layer not coating the negative pole active substance layer, and the negative pole mass flow body of not coating the negative pole active substance layer is as negative pole utmost point ear. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon, silicon, or the like. In order to ensure that the fuse is not fused when a large current is passed, the number of the positive electrode tabs is multiple and the positive electrode tabs are stacked together, and the number of the negative electrode tabs is multiple and the negative electrode tabs are stacked together. The material of the isolation film may be PP (polypropylene) or PE (polyethylene). In addition, the electrode assembly may have a winding structure or a lamination structure, and the embodiment of the present application is not limited thereto.

The development of battery technology needs to consider various design factors, such as performance parameters of energy density, cycle life, discharge capacity, charge and discharge rate, and the like. The electrode assembly is a part of the battery cell in which electrochemical reactions occur, and the utilization rate of the electrode assembly affects the energy density of the battery cell. However, the utilization rate of the electrode assembly in the prior art is not high, which is not favorable for improving the energy density of the battery.

The inventors have found through studies that the electrode assembly is mainly formed by winding or laminating a positive electrode sheet and a negative electrode sheet. When the pole piece is manufactured, active substance slurry is required to be coated on a base material, and continuous coating is generally adopted when the pole piece is coated, namely, the active substance slurry is continuously coated on two sides of the base material except for a reserved tab and a die cutting area. Thus, after the positive pole piece and the negative pole piece are wound, the active material layer of the pole piece positioned on the outermost layer cannot play a role, so that the utilization rate of the electrode assembly is not high, and the improvement of the energy density of the battery is not facilitated.

In view of this, the present application provides an electrode assembly including a first pole piece, a second pole piece, and a third pole piece. The first pole piece and the second pole piece have opposite polarities, and are wound or laminated to form a main body part. The first pole piece comprises a tail part positioned at the outermost layer of the main body part. The polarity of the third pole piece is opposite to that of the first pole piece, an active substance layer is arranged on one side of the third pole piece, and the active substance layer and the ending part are at least partially arranged oppositely.

This electrode assembly is through setting up the third pole piece, and the polarity opposite with first pole piece is provided with active material layer only unilateral to the third pole piece, and the active material layer of third pole piece sets up with the outermost active material layer of main part is at least partly relative for metal ion can produce or store the electric energy in third pole piece and first pole piece between the removal. Therefore, the utilization rate of the active material layer on the outermost layer of the main body part can be improved, the utilization rate of the electrode assembly is improved, and the energy density of the battery cell is improved.

The technical scheme described in the embodiment of the application is suitable for the battery and the electric equipment using the battery.

The electric equipment can be vehicles, mobile phones, portable equipment, notebook computers, ships, spacecrafts, electric toys, electric tools and the like. Spacecraft include aircraft, rockets, space shuttles, and spacecraft, among others; electric toys include stationary or mobile electric toys, such as game machines, electric car toys, electric ship toys, electric airplane toys, and the like; the electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and electric tools for railways, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, electric impact drills, concrete vibrators, and electric planers. The embodiment of the present application does not specifically limit the above-mentioned electric devices.

For convenience of description, the following embodiments will be described by taking an electric device as the vehicle 1000.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a vehicle 1000 according to some embodiments of the present disclosure. The vehicle 1000 may be a fuel automobile, a gas automobile, or a new energy automobile, and the new energy automobile may be a pure electric automobile, a hybrid electric automobile, or a range-extended automobile, etc. The battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom or the head or the tail of the vehicle 1000. The battery 100 may be used for power supply of the vehicle 1000, for example, the battery 100 may serve as an operation power source of the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300, the controller 200 being configured to control the battery 100 to supply power to the motor 300, for example, for starting, navigation, and operational power requirements while the vehicle 1000 is traveling.

In some embodiments of the present application, the battery 100 may not only serve as an operating power source of the vehicle 1000, but also serve as a driving power source of the vehicle 1000, instead of or in part of fuel or natural gas to provide driving power for the vehicle 1000.

Referring to fig. 2, fig. 2 is an exploded view of a battery 100 according to some embodiments of the present disclosure. The battery 100 includes a case 10 and a battery cell 20, and the battery cell 20 is accommodated in the case 10. The case 10 is used to provide a receiving space for the battery cells 20, and the case 10 may have various structures. In some embodiments, the case 10 may include a first portion 11 and a second portion 12, the first portion 11 and the second portion 12 cover each other, and the first portion 11 and the second portion 12 together define a receiving space for receiving the battery cell 20. The second part 12 may be a hollow structure with one open end, the first part 11 may be a plate-shaped structure, and the first part 11 covers the open side of the second part 12, so that the first part 11 and the second part 12 jointly define a containing space; the first portion 11 and the second portion 12 may be both hollow structures with one side open, and the open side of the first portion 11 may cover the open side of the second portion 12. Of course, the case 10 formed by the first and second portions 11 and 12 may have various shapes, such as a cylinder, a rectangular parallelepiped, and the like.

In the battery 100, there may be a plurality of battery cells 20, and the plurality of battery cells 20 may be connected in series or in parallel or in series-parallel, where in series-parallel refers to both series connection and parallel connection among the plurality of battery cells 20. The plurality of battery cells 20 can be directly connected in series or in parallel or in series-parallel, and the whole formed by the plurality of battery cells 20 is accommodated in the box body 10; of course, the battery 100 may also be formed by connecting a plurality of battery cells 20 in series, in parallel, or in series-parallel to form a battery module, and then connecting a plurality of battery modules in series, in parallel, or in series-parallel to form a whole, and accommodating the whole in the case 10. The battery 100 may further include other structures, for example, the battery 100 may further include a bus member for achieving electrical connection between the plurality of battery cells 20.

Wherein, each battery cell 20 may be a secondary battery cell or a primary battery cell; but not limited thereto, a lithium sulfur battery cell, a sodium ion battery cell, or a magnesium ion battery cell may also be used. The battery cell 20 may be cylindrical, flat, rectangular parallelepiped, or other shape.

Referring to fig. 3, fig. 3 is an exploded schematic view of a battery cell 20 according to some embodiments of the present disclosure. The battery cell 20 refers to the smallest unit constituting the battery 100. As shown in fig. 3, the battery cell 20 includes an end cap 21, an electrode assembly 22, a case 23, and other functional components.

The end cap 21 refers to a member that covers an opening of the case 23 to insulate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 21 may be adapted to the shape of the housing 23 to fit the housing 23. Alternatively, the end cap 21 may be made of a material (e.g., an aluminum alloy) having a certain hardness and strength, so that the end cap 21 is not easily deformed when being impacted, and the battery cell 20 may have a higher structural strength and improved safety. The end cap 21 may be provided with functional components such as electrode terminals (not shown in the drawings). The electrode terminals may be used to electrically connect with the electrode assembly 22 for outputting or inputting electric power of the battery cell 20. The material of the end cap 21 may be various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present invention is not limited thereto. In some embodiments, insulation may also be provided on the inside of the end cap 21, which may be used to isolate the electrical connection components within the housing 23 from the end cap 21 to reduce the risk of short circuits. Illustratively, the insulator may be plastic, rubber, or the like.

The case 23 is an assembly for mating with the end cap 21 to form an internal environment of the battery cell 20, wherein the formed internal environment may be used to house the electrode assembly 22, electrolyte, and other components. The housing 23 and the end cap 21 may be separate components, and an opening may be formed in the housing 23, and the opening may be covered by the end cap 21 to form the internal environment of the battery cell 20. Without limitation, the end cap 21 and the housing 23 may be integrated, and specifically, the end cap 21 and the housing 23 may form a common connecting surface before other components are inserted into the housing, and when it is necessary to seal the interior of the housing 23, the end cap 21 covers the housing 23. The housing 23 may be of various shapes and various sizes, such as rectangular parallelepiped, cylindrical, hexagonal prism, etc. Specifically, the shape of the case 23 may be determined according to the specific shape and size of the electrode assembly 22. The material of the housing 23 may be various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not limited in this embodiment.

Referring to fig. 4, fig. 4 is a schematic structural diagram of an electrode assembly 22 according to some embodiments of the present disclosure. The present embodiments provide an electrode assembly 22, and the electrode assembly 22 includes a first pole piece 2211, a second pole piece 2212, and a third pole piece 222. The first and second pole pieces 2211 and 2212 have opposite polarities, and the first and second pole pieces 2211 and 2212 are wound or laminated to form the main body 221. The first pole piece 2211 includes a closeout 22111 located at the outermost layer of the body portion 221. The third pole piece 222 is opposite in polarity to the first pole piece 2211. An active material layer 2221 is provided on one side of the third pole piece 222, and the active material layer 2221 is provided at least partially facing the end 22111.

The electrode assembly 22 is a component in the battery cell 20 where electrochemical reactions occur. One or more electrode assemblies 22 may be contained within the case 23.

One of the first and second pole pieces 2211 and 2212 is a positive pole piece, and the other is a negative pole piece. The polarity of the third pole piece 222 is opposite to that of the first pole piece 2211, and the polarity of the third pole piece 222 is the same as that of the second pole piece 2212. For example, when the first pole piece 2211 is a positive pole piece, the second pole piece 2212 is a negative pole piece, and the third pole piece 222 is also a negative pole piece. When the first pole piece 2211 is a negative pole piece, the second pole piece 2212 is a positive pole piece, and the third pole piece 222 is also a positive pole piece. Both sides of the first and second pole pieces 2211 and 2212 are provided with an active material layer 2221, and only one side of the third pole piece 222 is provided with the active material layer 2221. The third pole piece 222 is provided with a tab, and the tab of the third pole piece 222 may be welded with the tab of the main body 221, so as to output or input electric energy.

The main body part 221 is a structure formed by winding or laminating the first and second pole pieces 2211 and 2212, the main body part 221 is a portion of the electrode assembly 22 where electrochemical reactions mainly occur, and metal ions move between the first and second pole pieces 2211 and 2212 to generate or store electric energy. Generally, the main body 221 further includes a second separation film 2213, and the first pole piece 2211, the second separation film 2213 and the second pole piece 2212 are wound or laminated to form the main body 221. The second isolation film 2213 is located between the first pole piece 2211 and the second pole piece 2212 to isolate the first pole piece 2211 from the second pole piece 2212, so as to prevent the first pole piece 2211 from contacting with the second pole piece 2212 and causing short circuit. Here, the second isolation film 2213 is a thin film having an insulating and isolating function, but the second isolation film 2213 allows metal ions to pass through, so that the metal ions can move between the first pole piece 2211 and the second pole piece 2212 to generate or store electric energy. The second isolation film 2213 may be made of PP (polypropylene) or PE (polyethylene).

The ending 22111 is specifically the portion of the first pole piece 2211 located at the outermost layer of the main body portion 221, or the ending 22111 is the portion of the first pole piece 2211 exposed outside the main body portion 221. The second pole piece 2212 is wound or laminated inside the main body portion 221 by the first pole piece 2211. The side of the third pole piece 222 on which the active material layer 2221 is disposed is at least partially disposed opposite the end 22111, so that metal ions can move between the third pole piece 222 and the first pole piece 2211 to generate or store electric energy.

The electrode assembly 22 is configured to generate or store electric energy by providing the third pole piece 222, wherein the active material layer 2221 is provided on only one side of the third pole piece 222 and has a polarity opposite to that of the first pole piece 2211, and the active material layer 2221 of the third pole piece 222 is at least partially disposed opposite to the active material layer on the outermost layer of the main body portion 221, so that metal ions can move between the third pole piece 222 and the first pole piece 2211. Thus, the utilization rate of the active material layer on the outermost layer of the body 221 can be increased, which is advantageous for increasing the utilization rate of the electrode assembly 22 and increasing the energy density of the battery cell 20.

Referring to fig. 5, 6 and 7, fig. 5 is a schematic structural diagram of an electrode assembly 22 (with a winding member 223 added on the basis of fig. 4) according to some embodiments of the present application. Fig. 6 is a schematic diagram illustrating connection between the winding member 223 and the third pole piece 222 according to some embodiments of the present application. Fig. 7 is a schematic top view of a winding member 223 connected to a third pole piece 222 according to some embodiments of the present application. In some embodiments, the electrode assembly 22 includes a winding 223, and the third pole piece 222 is disposed on the winding 223. The winding member 223 is wound around the outside of the body portion 221 such that the active material layer 2221 is at least partially disposed opposite the ending portion 22111.

The winding member 223 is a member wound around the outside of the body portion 221. The winding member 223 may be a band-shaped structure, a strip-shaped structure, a thread-shaped structure, or the like. For example, the wrapping 223 may be an insulating tape, an adhesive tape, a thread, or the like.

The phrase "the third pole piece 222 is disposed on the winding member 223" means that the third pole piece 222 is connected to the winding member 223 when the winding member 223 is not wound on the main body portion 221. For example, the third pole piece 222 may be adhered to the winding member 223 such that the active material layer 2221 of the third pole piece 222 and the ending portion 22111 are at least partially disposed opposite to each other when the winding member 223 is wound around the main body portion 221.

The winding member 223 is wound on the outer side of the main body 221 to fix the main body 221, thereby preventing the main body 221 from loosening or falling apart. In addition, the third pole piece 222 is arranged on the winding piece 223, so that the winding piece 223 is wound around the main body portion 221, the third pole piece 222 and the main body portion 221 are limited, the third pole piece 222 can be ensured to be at least partially opposite to the ending portion 22111, the third pole piece 222 is prevented from deviating when the electrode assembly 22 is placed into the shell 23, the outermost active material layer of the main body portion 221 is utilized, the utilization rate of the electrode assembly 22 is improved, and the energy density of the single battery 20 is improved.

In some embodiments, the third pole piece 222 is disposed on an inner surface of the winding member 223.

The phrase "the third pole piece 222 is disposed on the inner surface of the winding member 223" means that the third pole piece 222 is disposed on the winding member 223 when the winding member 223 is not wound on the main body portion 221, and the side of the winding member 223 on which the third pole piece 222 is disposed faces the main body portion 221 when the winding member 223 is wound on the main body portion 221, so that the third pole piece 222 is located between the main body portion 221 and the winding member 223.

By providing the third pole piece 222 on the inner surface of the winding member 223, the distance between the third pole piece 222 and the ending portion 22111 is reduced, which is beneficial for the metal ions to move between the third pole piece 222 and the first pole piece 2211, and improves the utilization rate of the active material layer on the outermost layer of the main body portion 221.

In some embodiments, the electrode assembly 22 includes a plurality of third electrodes 222, and the plurality of third electrodes 222 are spaced apart in the length direction of the winding member 223. The active material layer 2221 of the third pole piece 222 is disposed away from the winding member 223. When the winding member 223 is wound around the main body portion 221, the active material layer 2221 of each third pole piece 222 is disposed opposite to the ending portion 22111.

In some embodiments, the third pole piece 222 is disposed on an outer surface of the winding member 223, i.e., the winding member 223 is located between the third pole piece 222 and the main body portion 221. At this time, the winding member 223 should allow metal ions to pass therethrough so that the metal ions move between the third pole piece 222 and the first pole piece 2211, improving the utilization rate of the active material layer of the outermost layer of the main body portion 221.

In some embodiments, the inner surface of the wrapping 223 is provided with a first layer of glue, and the trailing end 2232 of the wrapping 223 is adhered to the leading end 2231 of the wrapping 223 by the first layer of glue.

The inner surface of the winding member 223 refers to a surface of the winding member 223 facing the body part 221. The first layer of adhesive may cover the entire inner surface, for example, the wrapping 223 may be an adhesive tape. Of course, the first adhesive layer may cover only a portion of the inner surface, for example, the first adhesive layer may be disposed only at the tail end 2232 of the wrapping member 223. After the wrapping member 223 is wrapped around the body portion 221, glue may be applied between the leading end 2231 and the trailing end 2232 of the wrapping member 223 to adhere the leading end 2231 and the trailing end 2232, the glue forming a first layer of glue when it dries.

Through setting up first glue film, the head and the tail of wrapping 223 of being convenient for bond, reduce the probability of wrapping 223 head and the tail separation, promote the wrapping 223 to main part 221 and third pole piece 222's spacing effect.

Referring to fig. 4, 5 and 8, fig. 8 is a schematic structural view of an electrode assembly 22 (a first separator 224 is connected to a winding member 223) according to some embodiments of the present disclosure. In some embodiments, the electrode assembly 22 further includes a first isolation film 224, the first isolation film 224 being at least partially disposed between the third pole piece 222 and the closeout 22111 to insulate the third pole piece 222 from the closeout 22111.

The first isolation film 224 is a thin film having an insulating isolation function, but the first isolation film 224 allows metal ions to pass through so that the metal ions can move between the third pole piece 222 and the first pole piece 2211 to generate or store electric energy. The material of the first isolation film 224 may be PP (polypropylene) or PE (polyethylene).

The first isolation film 224 may be completely disposed between the third pole 222 and the closeout 22111, where the first isolation film 224 conforms to the shape and size of the third pole 222, such that the first isolation film 224 is capable of insulating the third pole 222 from the closeout 22111. The first isolation film 224 may also be partially disposed between the third electrode 222 and the end 22111 to isolate the third electrode 222 from the end 22111.

The first separation film 224 may be wrapped outside the body part 221 after the body part 221 is wound or laminated, and the third pole piece 222 and the winding member 223 may be disposed outside the first separation film 224 to form the electrode assembly 22.

By providing the first isolation film 224, the third pole piece 222 is isolated from the end 22111, so as to avoid short circuit caused by mutual contact between the third pole piece 222 and the end 22111.

Referring to fig. 8, 9 and 10, fig. 9 is a schematic view illustrating connection of a winding member 223, a third electrode sheet 222 and a first isolation film 224 according to some embodiments of the present application. Fig. 10 is a schematic top view of a winding 223, a third pole piece 222 and a first isolation film 224 according to some embodiments of the present disclosure. In some embodiments, the first separation film 224 is provided to the inner surface of the winding member 223 and arranged in the winding direction of the winding member 223.

The "first isolation film 224 is disposed on the inner surface of the winding member 223" means that the third pole piece 222 is connected to the winding member 223, and the first isolation film 224 is connected to the third pole piece 222 or the winding member 223. After the winding or lamination of the body part 221 is completed, the winding member 223 to which the third electrode sheet 222 and the first separation film 224 are connected is directly wound around the body part 221 to form the electrode assembly 22.

By disposing the first isolation film 224 on the inner surface of the winding member 223, the first isolation film 224 can be disposed between the third electrode sheet 222 and the ending part 22111 when the winding member 223 winds the main body part 221, which is simple and convenient and is beneficial to improving the production efficiency of the electrode assembly 22.

In some embodiments, the electrode assembly 22 includes a plurality of third electrodes 222 and a plurality of first separators 224, the third electrodes 222 corresponding one-to-one to the first separators 224. The first isolation film 224 is disposed on the side of the third pole piece 222 having the active material layer 2221, and along the thickness direction (a direction shown in fig. 8) of the main body portion 221, the projection of the first isolation film 224 on the winding piece 223 completely covers the projection of the third pole piece 222 on the winding piece 223. In addition, the projection of the third pole piece 222 on the winding 223 is located within the edge of the winding 223. In short, the first separator 224 completely covers the active material layer 2221 of the third pole piece 222, but does not completely cover the winding member 223.

Taking the winding member 223 as a long bar as an example, in the length direction of the winding member 223, the size of the third pole piece 222 is smaller than the size of the first isolation film 224, and the size of the first isolation film 224 is smaller than the size of the winding member 223. In the width direction of the winding member 223, the size of the third pole piece 222 is smaller than that of the first isolation film 224, and the size of the first isolation film 224 is smaller than that of the winding member 223.

Referring to fig. 11 and 12, fig. 11 is a schematic structural view of an electrode assembly 22 (a first separation film 224 completely covers a winding member 223) according to some embodiments of the present disclosure. Fig. 12 is a schematic connection diagram of the winding member 223, the third pole piece 222 and the first isolation film 224 (the first isolation film 224 completely covers the winding member 223) according to some embodiments of the present application. In some embodiments, the first isolation diaphragm 224 completely covers the inner surface. The side of the first isolation film 224 facing away from the inner surface is provided with a second glue layer, and the tail end 2232 of the first isolation film 224 is adhered to the head end 2231 of the winding member 223 through the second glue layer.

"the first separation film 224 completely covers the inner surface" means that a projection of the first separation film 224 on the winding member 223 completely coincides with the winding member 223 along the thickness direction of the body portion. Taking the winding member 223 as an example of a long strip structure, in the length direction of the winding member 223, the size of the third pole piece 222 is smaller than the size of the first isolation film 224, and the size of the first isolation film 224 is equal to the size of the winding member 223. In the width direction of the winding member 223, the size of the third pole piece 222 is smaller than that of the first isolation film 224, and the size of the first isolation film 224 is equal to that of the winding member 223.

The "side of the first isolation film 224 facing away from the inner surface is provided with the second glue layer", that is, the side of the first isolation film 224 facing the main body 221 is provided with the second glue layer. The second adhesive layer may cover the entire side of the first release film 224 facing away from the inner surface. Of course, the second adhesive layer may cover only a part of the first isolation film 224 facing away from the inner surface, for example, the second adhesive layer may be disposed only at the tail end 2232 of the first isolation film 224. After the winding member 223 is wound around the body 221, glue may be applied between the head end 2231 of the winding member 223 and the tail end 2232 of the first separation film 224 to adhere the head end 2231 of the winding member 223 and the tail end 2232 of the first separation film 224, and the glue forms a second glue layer after being dried.

Through covering the inner surface with first barrier film 224 completely, first barrier film 224's area is great, even if third pole piece 222 takes place certain dislocation with first barrier film 224, third pole piece 222 is difficult for contacting with ending part 22111, is favorable to promoting third pole piece 222 and ending part 22111's insulating isolation effect. Through setting up the second glue film, be convenient for bond tail end 2232 of first barrier film 224 in the head end 2231 of winding 223 through the second glue film, reduce the probability of winding 223 head-to-tail separation, promote the spacing effect of winding 223 to main part 221 and third pole piece 222.

Referring to fig. 11, in some embodiments, the third electrode 222 is disposed on both sides of the main body 221 along the thickness direction of the main body 221.

The electrode assembly 22 includes two third pole pieces 222, and the two third pole pieces 222 are disposed on both sides of the main body portion 221 in the thickness direction.

In the case where the first and second pole pieces 2211 and 2212 are laminated to form the main body portion 221, both ends of the main body portion 221 are the ending portions 22111 of the first pole piece 2211 in the thickness direction of the main body portion 221. The two third pole pieces 222 are disposed on both sides of the main body 221 in the thickness direction, and can completely cover the end 22111, which is advantageous for improving the utilization rate of the electrode assembly 22.

In the case where the first and second pole pieces 2211 and 2212 are wound to form the main body portion 221, the outer circumference of the main body portion 221 is defined by the ending portion 22111 of the first pole piece 2211. The two third pole pieces 222 are disposed on both sides of the main body portion 221 in the thickness direction, and can cover most of the tail portion 22111, which is advantageous for improving the utilization rate of the electrode assembly 22.

Through all setting up third pole piece 222 in the both sides of main part 221, increase third pole piece 222 and the relative total area of ending part 22111, further promote the utilization ratio to the outermost active material layer of main part 221, be favorable to improving electrode subassembly 22's utilization ratio, improve battery cell 20's energy density.

Referring to fig. 13, fig. 13 is a schematic structural diagram of an electrode assembly 22 (the third electrode sheet 222 includes a first connecting section 2222, a second connecting section 2223 and a third connecting section 2224) according to some embodiments of the present disclosure. In some embodiments, the third pole piece 222 includes a first connection section 2222, a second connection section 2223, and a third connection section 2224. The first connection section 2222 and the second connection section 2223 are respectively provided at both sides of the body part 221 in the thickness direction of the body part 221. The third connecting section 2224 connects the first connecting section 2222 and the second connecting section 2223.

The electrode assembly 22 includes one third electrode 222, and the third electrode 222 has a first connection section 2222, a second connection section 2223, and a third connection section 2224 connected in sequence. Among them, the first connecting section 2222 and the second connecting section 2223 are located at both sides of the body portion 221 in the thickness direction of the body portion 221.

The first connecting section 2222 and the second connecting section 2223 are both arranged opposite to the ending part 22111, and the third connecting section 2224 may be arranged opposite to the ending part 22111, so that the third pole piece 222 covers most of the outermost active material layer 2221 of the main body part 221, and the area of the third pole piece 222 opposite to the ending part 22111 is larger, which is beneficial to improving the utilization rate of the outermost active material layer of the main body part 221 and improving the energy density of the battery cell 20.

Referring to fig. 13, in some embodiments, the first and second pole pieces 2211 and 2212 are wound to form the main body portion 221. The body portion 221 includes a flat area 2214 and a bent area 2215 connected to the flat area 2214. The third chip 222 includes a first connection section 2222, a second connection section 2223, and a third connection section 2224. The first connecting section 2222 and the second connecting section 2223 are provided on both sides of the flat area 2214, respectively, in the thickness direction of the body portion 221. The third connecting section 2224 connects the first connecting section 2222 and the second connecting section 2223, and is disposed opposite to the bending region 2215.

For the arrangement where the first and second pole pieces 2211 and 2212 are wound to form the body portion 221, the body portion 221 has a flat area 2214 and a bent area 2215. The flat area 2214 is a portion of the main body portion 221 that extends along a straight trajectory. The bending region 2215 is a portion of the main body 221 connected to the flat region 2214, and the bending region 2215 may extend along a circular arc trajectory.

The first connecting section 2222 and the second connecting section 2223 are disposed on both sides of the flat area 2214, opposite to the flat area 2214, and an active material layer outside the flat area 2214 may be used. The third connecting section 2224 is opposite to the bending region 2215, and an active material layer of the bending region 2215 can also be utilized.

Through setting up first linkage section 2222 and second linkage section 2223 respectively in the both sides of straight district 2214, third linkage section 2224 is relative with inflection district 2215 for third pole piece 222 has covered the outmost active substance layer of main part 221 of most part, and the area that third pole piece 222 is relative with final phase portion 22111 is great, is favorable to promoting the utilization ratio to the outmost active substance layer of main part 221, improves battery cell 20's energy density.

In some embodiments, the projection of the third pole piece 222 does not exceed the projection of the ending 22111 along the thickness direction of the body portion 221.

"the projection of the third electrode 222 does not exceed the projection of the ending part 22111 in the thickness direction of the main body part 221" includes two schemes that the projection of the third electrode 222 completely overlaps the projection of the ending part 22111 or the projection of the third electrode 222 is located in the projection of the ending part 22111 in the thickness direction of the main body part 221.

The projection of the third pole piece 222 can completely coincide with the projection of the ending portion 22111, so that the utilization rate of the active material on the outermost layer of the main body 221 can be improved while the third pole piece 222 is not wasted. The projection of the third pole piece 222 may also be located in the projection of the tail 22111, so that the utilization rate of the active material at the outermost layer of the main body 221 may also be increased to a certain extent, and meanwhile, the third pole piece 222 is fully utilized, which does not cause waste of the third pole piece 222.

Taking the technical solution shown in fig. 5 as a first embodiment, in the first embodiment, the electrode assembly 22 includes a first separator 224 and two third electrodes 222, the two third electrodes 222 are respectively disposed on both sides of the main body portion 221 in the thickness direction, and the first separator 224 is wound around the outside of the main body portion 221. Taking the solution shown in fig. 8 as a second embodiment, in the second embodiment, the electrode assembly 22 includes two first separators 224 and two third electrodes 222, the first separators 224 and the third electrodes 222 are in one-to-one correspondence, and the two third electrodes 222 are respectively disposed on two sides of the main body portion 221 in the thickness direction. Taking the solution shown in fig. 11 as a third embodiment, in the third embodiment, the electrode assembly 22 includes a first isolation film 224 and two third pole pieces 222, the first isolation film 224 is connected to the third pole pieces 222, and its projection on the winding piece 223 along the thickness direction of the main body portion 221 completely coincides with the winding piece 223. The two third tabs 222 are respectively disposed on both sides of the body portion 221 in the thickness direction. Taking the technical solution shown in fig. 13 as a fourth embodiment, in the fourth embodiment, a first pole piece 2211 and a second pole piece 2212 are wound to form a main body portion 221. The body portion 221 includes a flat area 2214 and a bent area 2215 connected to the flat area 2214. The third pole piece 222 includes a first connection section 2222, a second connection section 2223, and a third connection section 2224. The first connecting section 2222 and the second connecting section 2223 are respectively provided on both sides of the flat area 2214 in the thickness direction of the main body portion 221. The third connecting section 2224 connects the first connecting section 2222 and the second connecting section 2223, and is disposed opposite to the bending region 2215. The prior art is used as a comparative example.

In the above first, second, third, fourth and comparative examples, the thickness of the second separation film 2213 is 0.012mm, the circumference of the outer wall of the winding needle is 260mm, the thickness of the first pole piece 2211 is 0.1496mm, the thickness of the second pole piece 2212 is 0.1168mm, the first pole piece 2211 has 42 layers, the second pole piece 2212 has 40 layers, and the thickness of the third pole piece 222 is the same as the single-layer thickness of the second pole piece 2212.

The comparative volumetric energy density percentages (VED) of the first, second, third and fourth examples above were recorded, summarized in table 1 below:

TABLE 1

Group of	VED
		First embodiment	101.17％
Second embodiment	101.17％
		Third embodiment	101.17％
Fourth embodiment	101.41％
		First comparative example	100％

Therefore, in the application embodiment, the winding member 223 is wound on the outer side of the main body portion 221 to fix the main body portion 221, so as to prevent the main body portion 221 from loosening or falling apart. In addition, the third pole piece 222 is arranged on the winding piece 223, so that the winding piece 223 limits the third pole piece 222 and the main body part 221 while winding the main body part 221, the third pole piece 222 can be ensured to be at least partially opposite to the ending part 22111, the third pole piece 222 is prevented from deviating when the electrode assembly 22 is placed into the shell 23, the outermost active material layer of the main body part 221 is utilized, the utilization rate of the electrode assembly 22 is improved, and the energy density of the battery cell 20 is improved.

The embodiment of the application also provides a battery cell 20, the battery cell 20 comprises a shell 23 and the electrode assembly 22, and the electrode assembly 22 is accommodated in the shell 23.

The embodiment of the application also provides a battery 100, the battery 100 includes a box 10 and the above battery cell 20, and the battery cell 20 is accommodated in the box 10.

The embodiment of the present application further provides an electric device, where the electric device includes the above battery 100, and the battery 100 is used for providing electric energy.

Please refer to fig. 4-13 according to some embodiments of the present application.

The present embodiments provide an electrode assembly 22, where the electrode assembly 22 includes a first pole piece 2211, a second pole piece 2212, and a third pole piece 222. The first and second pole pieces 2211 and 2212 have opposite polarities, and the first and second pole pieces 2211 and 2212 are wound or laminated to form the main body 221. The first pole piece 2211 includes a closeout 22111 located at the outermost layer of the body portion 221. The polarity of the third pole piece 222 is opposite to that of the first pole piece 2211, an active material layer 2221 is provided on one side of the third pole piece 222, and the active material layer 2221 is at least partially disposed opposite to the end 22111.

The electrode assembly 22 includes a winding member 223, and the third pole piece 222 is disposed on the winding member 223. The winding member 223 is wound around the outside of the body portion 221 such that the active material layer 2221 is at least partially disposed opposite the ending portion 22111. The inner surface of the wrapping member 223 is provided with a first glue layer, and the tail end 2232 of the wrapping member 223 is adhered to the head end 2231 of the wrapping member 223 by the first glue layer.

Electrode assembly 22 also includes a first separator 224, first separator 224 being at least partially disposed between third electrode 222 and closeout 22111 to insulate and isolate third electrode 222 from closeout 22111.

The first and second pole pieces 2211 and 2212 are wound to form the main body 221, and the main body 221 includes a straight area 2214 and a bent area 2215 connected to the straight area 2214. The third chip 222 includes a first connection section 2222, a second connection section 2223, and a third connection section 2224. The first connecting section 2222 and the second connecting section 2223 are provided on both sides of the flat area 2214, respectively, in the thickness direction of the body portion 221. The third connecting section 2224 connects the first connecting section 2222 and the second connecting section 2223, and is disposed opposite to the bending region 2215.

The electrode assembly 22 is configured to generate or store electric energy by providing the third pole piece 222, wherein the active material layer 2221 is provided on only one side of the third pole piece 222 and has a polarity opposite to that of the first pole piece 2211, and the active material layer 2221 of the third pole piece 222 is at least partially disposed opposite to the active material layer on the outermost layer of the main body portion 221, so that metal ions can move between the third pole piece 222 and the first pole piece 2211. Thus, the utilization rate of the active material layer on the outermost layer of the body portion 221 can be improved, which is advantageous for improving the utilization rate of the electrode assembly 22 and improving the energy density of the battery cell 20.

The wrapping member 223 is wrapped around the outer side of the main body 221 to fix the main body 221 and prevent the main body 221 from loosening or falling apart. In addition, the third pole piece 222 is arranged on the winding piece 223, so that the winding piece 223 is wound around the main body portion 221, the third pole piece 222 and the main body portion 221 are limited, the third pole piece 222 can be ensured to be at least partially opposite to the ending portion 22111, the third pole piece 222 is prevented from deviating when the electrode assembly 22 is placed into the shell 23, the outermost active material layer of the main body portion 221 is utilized, the utilization rate of the electrode assembly 22 is improved, and the energy density of the single battery 20 is improved. Through setting up first glue film, the winding 223 of being convenient for bonds from beginning to end, reduces the probability of winding 223 separation from beginning to end, promotes the spacing effect of winding 223 to main part 221 and third pole piece 222.

By providing the first isolation film 224, the third pole piece 222 is isolated from the ending portion 22111, so as to avoid short circuit caused by mutual contact between the third pole piece 222 and the ending portion 22111.

Through setting up first linkage section 2222 and second linkage section 2223 respectively in the both sides of straight district 2214, third linkage section 2224 is relative with inflection district 2215 for the outmost active material layer of main part 221 that has mostly covered by third pole piece 222, the area that third pole piece 222 is relative with ending portion 22111 is great, is favorable to promoting the utilization ratio to the outmost active material layer 2221 of main part 221, improves battery cell 20's energy density.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims (14)

1. An electrode assembly, comprising:

the electrode comprises a first pole piece and a second pole piece with opposite polarities, wherein the first pole piece and the second pole piece are wound or laminated to form a main body part, and the first pole piece comprises a tail part positioned on the outermost layer of the main body part;

and the third pole piece is opposite to the first pole piece in polarity, an active substance layer is arranged on one side of the third pole piece, and the active substance layer and the ending part are at least partially arranged oppositely.

2. The electrode assembly of claim 1, wherein the electrode assembly comprises:

and the winding piece is wound on the outer side of the main body part, so that the active material layer and the ending part are at least partially arranged oppositely.

3. The electrode assembly of claim 2, wherein the third electrode is disposed on an inner surface of the winding.

4. The electrode assembly of claim 2, wherein the inner surface of the winding member is provided with a first glue layer, and the trailing end of the winding member is adhered to the leading end of the winding member by the first glue layer.

5. The electrode assembly of claim 2, further comprising a first separator film disposed at least partially between the third pole piece and the terminal portion to insulate and separate the third pole piece from the terminal portion.

6. The electrode assembly according to claim 5, wherein the first separator is provided on an inner surface of the winding member and arranged in a winding direction of the winding member.

7. The electrode assembly of claim 6, wherein the first separator completely covers the inner surface, a second adhesive layer is disposed on a side of the first separator facing away from the inner surface, and the tail end of the first separator is adhered to the head end of the winding member through the second adhesive layer.

8. The electrode assembly according to claim 1, wherein the third pole piece is provided on both sides of the main body portion in a thickness direction of the main body portion.

9. The electrode assembly according to claim 1, wherein the third electrode includes a first connection section, a second connection section, and a third connection section, the first connection section and the second connection section being respectively disposed at both sides of the main body portion in a thickness direction of the main body portion, the third connection section connecting the first connection section and the second connection section.

10. The electrode assembly of claim 1, wherein the first and second pole pieces are wound to form the main body portion, the main body portion including a flat region and a bent region connected to the flat region;

the third pole piece comprises a first connecting section, a second connecting section and a third connecting section, and the first connecting section and the second connecting section are respectively arranged on two sides of the straight area along the thickness direction of the main body part, and the third connecting section is connected with the first connecting section and the second connecting section and is arranged opposite to the bending area.

11. The electrode assembly of claim 1, wherein a projection of the third pole piece does not exceed a projection of the tail portion along a thickness direction of the main body portion.

12. A battery cell, comprising:

a housing;

the electrode assembly of any of claims 1-11, contained within the housing.

13. A battery, comprising:

a box body;

the battery cell of claim 12, contained within the case.

14. An electrical consumer, characterized in that it comprises a battery according to claim 13 for providing electrical energy.

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