CN216450704U

CN216450704U - Electrode assembly, battery cell, battery and electric equipment

Info

Publication number: CN216450704U
Application number: CN202123125567.6U
Authority: CN
Inventors: 许虎; 董娇; 牛少军; 李星
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2021-12-13
Filing date: 2021-12-13
Publication date: 2022-05-06
Anticipated expiration: 2031-12-13

Abstract

The embodiment of the application provides an electrode subassembly, battery monomer, battery and consumer, belongs to battery technical field. The first pole piece is provided with a first winding starting end, the first pole piece comprises a first section and a second section which are continuously arranged along the winding direction, the first section is wound along the winding direction from the first winding starting end to form an inner ring layer, and the second section is wound along the winding direction from a position where the second section is connected with the first section to form an outer ring layer. The first section is provided with the rib, and the rib is convoluteed to continuous position along the direction of convoluteing, and the rib is used for strengthening first section. The reinforcing part plays a reinforcing role in the first section, so that the deformation resistance of the first section is enhanced, a strong self-supporting structure is formed on the inner ring layer of the first pole piece, the deformation resistance of the inner ring layer is enhanced, the risk of the central collapse and deformation of the electrode assembly is reduced, and lithium precipitation is effectively reduced.

Description

Electrode assembly, battery cell, battery and electric equipment

Technical Field

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

Background

With the development of new energy technology, batteries are more and more widely used, such as mobile phones, notebook computers, battery cars, electric automobiles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, electric tools, and the like.

The battery cell serves as an energy storage element, and generally chemically reacts with the electrolyte through an electrode assembly, thereby outputting electric energy. The electrode assembly generally includes a positive electrode sheet, a negative electrode sheet, and a separator, which are wound to form a wound structure. For a wound electrode assembly, a lithium precipitation phenomenon is easy to occur, and the service life of a battery cell is influenced.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides an electrode subassembly, battery monomer, battery and consumer, can reduce and educe lithium, improves the free life of battery.

In a first aspect, embodiments of the present application provide an electrode assembly including first and second opposite-polarity pole pieces, the first and second pole pieces being arranged in a stack and wound in a winding direction to form a wound structure; the first pole piece is provided with a first winding starting end and comprises a first section and a second section which are continuously arranged along the winding direction, the first section is wound along the winding direction from the first winding starting end to form an inner ring layer, the second section is wound along the winding direction from a position where the second section is connected with the first section to form an outer ring layer, and the outer ring layer is positioned on the outer side of the inner ring layer; the first section is provided with a reinforcing part, the reinforcing part is wound to the connecting position along the winding direction, and the reinforcing part is used for reinforcing the first section.

Among the above-mentioned technical scheme, the first section of first pole piece is equipped with the rib, and the rib plays the reinforcing action to the first section to the anti deformability of reinforcing first section makes the inner circle layer of first pole piece form stronger self-supporting structure, has strengthened the anti deformability of inner circle layer, reduces the risk that the electrode subassembly center sinks the deformation, thereby effectively reduces and educes lithium, improves the free life of battery.

In some embodiments, the reinforcement portion is beyond the first winding start end; or one end of the reinforcing part far away from the connecting position along the winding direction is aligned with the winding starting end.

Among the above-mentioned technical scheme, no matter be that the rib part surpasss first winding initiating terminal, still the one end that continuous position was kept away from to the rib aligns with first winding initiating terminal, all makes the rib cover whole first section, and the rib plays fine additional strengthening to first section whole section on the winding direction, and first section whole section has fine resistance to deformation ability.

In some embodiments, the second pole piece has a second winding start end; the first pole piece comprises a third section, the third section is wound from the first winding starting end to a first alignment position aligned with the second winding starting end along the winding direction, the first alignment position is adjacent to the second winding starting end and located on the outer side of the second winding starting end, and the first section forms at least one part of the third section.

In the above technical solution, the first section is formed at least in a part of the third section, that is, the reinforcement portion is disposed at the third section, since the third section is wound from the first winding start end to the first alignment position aligned with the second winding start end along the winding direction, the second pole piece opposite to the third section does not exist at the inner side of the third section, and the reinforcement portion is disposed at the third section, the third section is not likely to hinder the ion transmission between the first pole piece and the second pole piece.

In some embodiments, the third segment includes an excess segment that exceeds the second winding start end, the excess segment is wound from the first winding start end in the winding direction to a second alignment position aligned with the second winding start end, the second alignment position is adjacent to and inside the second winding start end, and the first segment forms at least a part of the excess segment.

In the above technical scheme, the first segment forms at least a part of the excess segment, that is, the reinforcement portion is disposed on the excess segment, and since the third segment is wound from the second winding start end along the winding direction to the second alignment position aligned with the second winding start end, the inner side and the outer side of the excess segment are not present in the second pole piece opposite to the first pole piece, and the reinforcement portion is disposed on the excess segment, thereby further reducing the influence of the reinforcement portion on the ion transmission between the first pole piece and the second pole piece. In addition, since the first segment forms at least a portion of the excess segment, the diameters of the turns in the inner turn layer formed by the first segment are made smaller, making it more difficult for the center of the electrode assembly to collapse.

In some embodiments, the reinforcement is wound at least 1 turn in the winding direction.

Among the above-mentioned technical scheme, the rib coils at least 1 circle along the direction of coiling, and the rib plays fine reinforcing effect to the first section for the first section has fine resistance to deformation ability.

In some embodiments, the reinforcement is wound 1-5 turns in the winding direction.

Among the above-mentioned technical scheme, the rib coils 1-5 circles along the direction of winding, has both played fine reinforcing effect to first section, makes the length of rib along the direction of winding can not the overlength again, reduces and strengthens the space that occupies, reduces the influence of rib to the free energy density of battery.

In some embodiments, the first electrode sheet includes a first current collector and a first active material layer, the first active material layer is disposed on a surface of the first current collector in a thickness direction, and the first current collector is provided with the reinforcement portion on at least one side in the thickness direction; the reinforcing part is arranged on one side, away from the first current collector, of the first active material layer of the first section; or, the reinforcement is disposed between the first active material layer of the first segment and the first current collector.

Among the above-mentioned technical scheme, if the rib sets up in the one side that the first active material layer of first section deviates from first mass flow body, the rib is located the top layer of first section, is convenient for arrange the rib in first section. If the reinforcing part is arranged between the first active material layer and the first current collector of the first section, the reinforcing part is not easy to obstruct the transmission of ions of the first active material layer.

In some embodiments, the reinforcing portion is a glue layer disposed on a surface of the first active material layer of the first segment facing away from the first current collector.

Among the above-mentioned technical scheme, the reinforcement is the glue film, is convenient for arrange it on the surface of first active material layer. The glue film bonds in the surface on first active material layer, is difficult for separating with first active material layer, and the rib plays fine reinforcing effect all the time to first section.

In some embodiments, the reinforcement is a second active material layer applied to the first active material layer of the first segment; the second active material layer and the first active material layer of the first segment have a total thickness greater than a thickness of the first active material layer of the second segment.

Among the above-mentioned technical scheme, the mode that the gross thickness through the first active material layer of second active material layer and first section is greater than the thickness of the first active material layer of second section is strengthened first section, and the implementation is simple, has fine economic nature. The second active material layer coats the first active material layer, and the second active material layer and the first active material layer have good integrity, so that the first section has good deformation resistance.

In some embodiments, the stiffness of the reinforcement is greater than the stiffness of the first active material layer of the first segment.

Among the above-mentioned technical scheme, the hardness of rib is greater than the hardness of the first active material layer of first section, and rib has better resistance to deformation than first active material layer, and the rib plays fine reinforcing effect to first section to the resistance to deformation of reinforcing first section.

In some embodiments, the first pole piece includes a first current collector and a first active material layer provided on a surface of the first current collector in a thickness direction; the first section the first mass flow body does not set up the first active material layer, the first section the first mass flow body surface in the thickness direction is provided with the rib, the hardness of rib is greater than the second section the hardness of first active material layer.

Among the above-mentioned technical scheme, the reinforcing part plays the reinforcing effect to the first mass flow body of first section, and the hardness of reinforcing part is greater than the hardness of the first active material layer of second section for the reinforcing part is stronger than the bending resistance of second section with the holistic anti deformability of the first mass flow body of first section, in order to reach the anti deformability's of reinforcing inner circle layer purpose.

In some embodiments, the electrode assembly further comprises a guard disposed on and stacked with the first pole piece; the first pole piece further has a first winding trailing end, and in the winding direction, one end of the guard member is aligned with or partially beyond the first winding trailing end.

Among the above-mentioned technical scheme, the guard piece plays the guard action to the first winding of first pole piece and receives the tail end, reduces the first winding of first pole piece and receives the tail end because of having sharp-pointed part to destroy the barrier film, and cause the risk of short circuit.

In some embodiments, the electrode assembly is of cylindrical construction.

In some embodiments, the electrode assembly includes a flat region and a bent region connected to the flat region; the reinforcement is at least partially located in the bending region.

Among the above-mentioned technical scheme, the reinforcing part is located the bending zone at least partially for the part that first section is located the bending zone has fine bending resistance, reduces the inward risk of caving in of pole piece in bending zone, effectively reduces and educes lithium.

In a second aspect, an embodiment of the present application provides a battery cell, including: any one of the embodiments of the first aspect provides an electrode assembly; a case for accommodating the electrode assembly.

In a third aspect, an embodiment of the present application provides a battery, including: the battery cell provided in any one of the embodiments of the second aspect; the box is used for accommodating the battery monomer.

In a fourth aspect, an embodiment of the present application provides an electric device, including the battery provided in any one of the embodiments of the third aspect.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used 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 for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

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 in accordance with some embodiments of the present application;

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

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 structural view of an electrode assembly provided in accordance with further embodiments of the present application;

FIG. 6 is a schematic structural view of an electrode assembly provided in accordance with still further embodiments of the present application;

FIG. 7 is a schematic view of a first pole piece after deployment according to some embodiments of the present disclosure;

FIG. 8 is a schematic illustration of a first pole piece after deployment according to further embodiments of the present disclosure;

FIG. 9 is a schematic illustration of a first pole piece after deployment according to further embodiments of the present disclosure;

FIG. 10 is a schematic view of a first electrode sheet according to still another embodiment of the present disclosure after being unfolded;

FIG. 11 is a schematic structural view of an electrode assembly provided in accordance with further embodiments of the present application;

FIG. 12 is a schematic view of an electrode assembly according to another embodiment of the present application;

fig. 13 is a flow chart of a method of manufacturing an electrode assembly provided by some embodiments of the present application;

fig. 14 is a schematic block diagram of a manufacturing apparatus of the electrode assembly provided in some embodiments of the present application.

Icon: 10-a box body; 11-a first part; 12-a second part; 20-a battery cell; 21-a housing; 22-an electrode assembly; 221-a first pole piece; 221 a-a first current collector; 221 b-a first active material layer; 2211-first section; 2212-second segment; 2212 a-attachment position; 2213-inner circle layer; 2214-outer ring layer; 2215-first winding start; 2216-first winding to receive tail end; 2217-third paragraph; 2217 a-first alignment position; 2217 b-second alignment position; 2218-excess segment; 222-a second pole piece; 2221-second winding start end; 2222-second winding tailing end; 223-a reinforcement; 2231-glue layer; 2232-a second active substance layer; 224-a barrier film; 225-a guard; 23-end caps; 24-an electrode terminal; 25-a current collecting member; 100-a battery; 200-a controller; 300-a motor; 1000-a vehicle; 2000-manufacturing equipment; 2100-providing means; 2200-an assembly device; a-a flat zone; b-a bending zone; x-the winding direction; z-thickness direction.

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 in the present application 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 above-described 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 the present application, the battery cell may include a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium lithium ion battery, a sodium ion battery, a magnesium ion battery, or the like, which is not limited in the embodiments of the present application. 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 monomer, the square battery monomer and the soft package battery monomer are also not limited in the embodiment of the 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 the case of a wound electrode assembly, after the positive electrode tab, the separator, and the negative electrode tab are wound, a center hole is formed at the center of the electrode assembly. The inventor finds that during the charge and discharge process of the electrode assembly, along with the expansion and contraction of the pole pieces, the central position of the electrode assembly is easy to collapse, the pole pieces are easy to wrinkle after collapsing, the pole pieces are not flat, and a gully-shaped gap is generated between the pole pieces, so that the ion transmission is blocked, and finally, the lithium precipitation is caused.

In view of this, embodiments of the present application provide an electrode assembly, a first pole piece of which includes a first segment wound in a winding direction from a first winding start end to form an inner coil layer and a second segment wound in the winding direction from a position where the second segment is connected to the first segment to form an outer coil layer, the outer coil layer being located outside the inner coil layer, which are continuously arranged in the winding direction. Wherein, the first section is provided with the rib, and the rib is convoluteed to continuous position along the direction of coiling, and the rib is used for strengthening the first section.

In the electrode assembly, the first section of the first pole piece is provided with the reinforcing part, and the reinforcing part plays a role in reinforcing the first section, so that the deformation resistance of the first section is enhanced, a strong self-supporting structure is formed on the inner ring layer of the first pole piece, the deformation resistance of the inner ring layer is enhanced, the risk of the central collapse and deformation of the electrode assembly is reduced, lithium precipitation is effectively reduced, and the service life of a battery cell is prolonged.

The electrode assembly described in the embodiments of the present application is applicable to a battery cell, a battery, and an electric device using the battery.

The electric equipment can be vehicles, mobile phones, portable equipment, notebook computers, ships, spacecrafts, electric toys, electric tools and the like. The vehicle can be a fuel oil vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or a range-extended vehicle 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 power tools include metal cutting electric power tools, grinding electric power tools, assembly electric power tools, and electric power 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 explanation, the following embodiments will be described by taking an electric device as an example of a vehicle.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a vehicle 1000 according to some embodiments of the present disclosure, a battery 100 is disposed inside the vehicle 1000, and the battery 100 may be disposed at a bottom portion, a head portion, or a tail portion 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 power requirements for operation during starting, navigation, and traveling of the vehicle 1000.

In some embodiments of the present application, the battery 100 may be used not only as an operating power source of the vehicle 1000, but also 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, in which the battery 100 includes a case 10 and a battery cell 20, and the case 10 is used for accommodating the battery cell 20.

The case 10 is a component for accommodating the battery cell 20, the case 10 provides an accommodating space for the battery cell 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, and the first portion 11 and the second portion 12 cover each other to define a receiving space for receiving the battery cell 20. The first and second portions 11 and 12 may be in various shapes, such as rectangular parallelepiped, cylindrical, etc. The first portion 11 may be a hollow structure with one side open, the second portion 12 may also be a hollow structure with one side open, and the open side of the second portion 12 is covered on the open side of the first portion 11, thereby forming the box body 10 with a receiving space. The first portion 11 may have a hollow structure with one side opened, the second portion 12 may have a plate-like structure, and the second portion 12 may cover the opened side of the first portion 11 to form the case 10 having an accommodating space. The first part 11 and the second part 12 may be sealed by a sealing element, which may be a sealing ring, a sealant or the like.

In the battery 100, one or more battery cells 20 may be provided. If there are a plurality of battery cells 20, the plurality of battery cells 20 may be connected in series, in parallel, or in series-parallel, where in series-parallel refers to that the plurality of battery cells 20 are connected in series or in parallel. A plurality of battery cells 20 may be connected in series, in parallel, or in series-parallel to form a battery module, and a plurality of battery modules may be connected in series, in parallel, or in series-parallel to form a whole, and may be accommodated in the case 10. Or all the battery cells 20 may be directly connected in series or in parallel or in series-parallel, and the whole of all the battery cells 20 is accommodated in the case 10.

In some embodiments, the battery 100 may further include a bus member, and the plurality of battery cells 20 may be electrically connected to each other through the bus member, so as to connect the plurality of battery cells 20 in series or in parallel or in series-parallel. The bus member may be a metal conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, or the like.

Referring to fig. 3, fig. 3 is an exploded view of a battery cell 20 according to some embodiments of the present disclosure, where the battery cell 20 includes a case 21, an electrode assembly 22, and an end cap 23.

The case 21 is a member for receiving the electrode assembly 22, the case 21 may be a hollow structure having one end opened, and the case 21 may be a hollow structure having opposite ends opened. The housing 21 may be in various shapes, such as a cylinder, a rectangular parallelepiped, or the like. The material of the housing 21 may be various, such as copper, iron, aluminum, steel, aluminum alloy, etc.

The electrode assembly 22 is a component in the battery cell 20 where electrochemical reactions occur. The electrode assembly 22 may include a positive electrode tab, a negative electrode tab, and a separator 224. The positive electrode sheet may include a positive electrode current collector and positive electrode active material layers coated on opposite sides of the positive electrode current collector. The negative electrode tab may include a negative electrode current collector and a negative electrode active material layer coated on opposite sides of the negative electrode current collector. The electrode assembly 22 has a cathode tab, which may be a portion of the cathode sheet not coated with the cathode active material layer, and an anode tab, which may be a portion of the anode sheet not coated with the anode active material layer.

The end cap 23 is a member that covers an opening of the case 21 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the end cover 23 can be adapted to the shape of the housing 21, for example, the end cover 23 is a rectangular plate-shaped structure adapted to the housing 21, and for example, the housing 21 is a cylindrical structure and the end cover 23 is a circular plate-shaped structure adapted to the housing 21. The end cap 23 may be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc.

In the battery cell 20, the number of the end caps 23 may be one or two. If the shell 21 is a hollow structure with an opening formed at one end, one end cover 23 can be correspondingly arranged; if the housing 21 is a hollow structure with openings formed at two ends, two end caps 23 may be correspondingly disposed, and the two end caps 23 respectively cover the openings at two ends of the housing 21.

The end cap 23 may be provided with electrode terminals 24, and the electrode terminals 24 are used to be electrically connected to tabs of the electrode assembly 22 to output electric power from the battery cell 20. The electrode terminals 24 may be directly connected to the tabs of the electrode assembly 22, or may be indirectly connected thereto.

As shown in fig. 3, taking the case where two end caps 23 are provided in the battery cell 20 as an example, the two end caps 23 are each provided with an electrode terminal 24, the electrode terminal 24 on one end cap 23 is a positive electrode terminal, and the electrode terminal 24 on the other end cap 23 is a negative electrode terminal. The positive electrode terminal is electrically connected to the positive tab through one current collecting member 25, and the negative electrode terminal is electrically connected to the negative tab through the other current collecting member 25.

Referring to fig. 4 to 6, fig. 4 is a schematic structural diagram of an electrode assembly 22 according to some embodiments of the present disclosure, fig. 5 is a schematic structural diagram of an electrode assembly 22 according to yet other embodiments of the present disclosure, and fig. 6 is a schematic structural diagram of an electrode assembly 22 according to yet other embodiments of the present disclosure.

The first pole piece 221 has a first winding start end 2215, the first pole piece 221 includes a first segment 2211 and a second segment 2212 continuously arranged in the winding direction X, the first segment 2211 is wound from the first winding start end 2215 in the winding direction X to form an inner coil layer 2213, the second segment 2212 is wound from a position 2212a where it is connected to the first segment 2211 in the winding direction X to form an outer coil layer 2214, and the outer coil layer 2214 is located outside the inner coil layer 2213. Here, the first segment 2211 is provided with a reinforcing part 223, the reinforcing part 223 is wound to the connecting position 2212a along the winding direction X, and the reinforcing part 223 is used for reinforcing the first segment 2211.

The first pole piece 221 and the second pole piece 222 have opposite polarities, and it can be understood that one of the first pole piece 221 and the second pole piece 222 is a positive pole piece, and the other is a negative pole piece. The first pole piece 221 may be a positive pole piece or a negative pole piece. For example, in fig. 4-6, the first pole piece 221 is a negative pole piece.

The electrode assembly 22 may further include a separation film 224, and the separation film 224 serves to separate the first and

second pole pieces

221 and 222. It can be understood that in the case where the separator 224 is provided in the electrode assembly 22, the first pole piece 221, the separator 224, and the second pole piece 222 are sequentially laminated and wound in the winding direction X to form a wound electrode assembly.

The winding direction X is a direction in which the first pole piece 221 and the second pole piece 222 are wound from the inside to the outside in the circumferential direction. In fig. 4 to 6, the winding direction X is clockwise.

The first winding start 2215 is an end of the first pole piece 221 near the center of the electrode assembly 22. The first pole piece 221 further has a first winding end 2216, and the first pole piece 221 extends from the first winding start end 2215 to the first winding end 2216 along the winding direction X. The intersection of first segment 2211 and second segment 2212 forms a connection location 2212a, first segment 2211 extends from first winding start 2215 to connection location 2212a along winding direction X, and second segment 2212 extends from connection location 2212a to first winding end 2216 along winding direction X. The first segment 2211 is wound from the first winding start end 2215 along the winding direction X to form an inner ring layer 2213, the inner ring layer 2213 has at least one turn of the first pole piece 221, and the first segment 2211 forms one turn of the first pole piece 221 of the inner ring layer 2213 every 360 degrees wound from the first winding start end 2215 along the winding direction X. The second segment 2212 is wound in the winding direction X from a position 2212a where the second segment 2212 is connected with the first segment 2211 to form an outer coil layer 2214, the outer coil layer 2214 has at least one turn of the first pole piece 221, and the second segment 2212 forms one turn of the first pole piece 221 of the outer coil layer 2214 every 360 degrees in the winding direction X from the position 2212 a. Illustratively, the number of turns of outer turn layer 2214 is greater than the number of turns of inner turn layer 2213. For example, the number of turns of the outer turn layer 2214 is 2 times or more the number of turns of the inner turn layer 2213.

The reinforcing part 223 is wound in the winding direction X to a connecting position 2212a of the first segment 2211 and the second segment 2212, and it can be understood that the end of the reinforcing part 223 in the winding direction X is aligned with the connecting position 2212 a. The reinforcement 223 is used to reinforce the first segment 2211, so that the deformation resistance of the whole of the first segment 2211 and the reinforcement 223 is greater than that of the second segment 2212, thereby achieving the purpose of enhancing the deformation resistance of the inner ring layer 2213. The reinforcement 223 may be disposed on an inner surface of the first section 2211, on an outer surface of the first section 2211, or between the current collector and the active material layer of the first section 2211.

In the embodiment of the present application, the first segment 2211 of the first pole piece 221 is provided with the reinforcing portion 223, and the reinforcing portion 223 reinforces the first segment 2211, so that the deformation resistance of the first segment 2211 is enhanced, the inner ring layer 2213 of the first pole piece 221 forms a strong self-supporting structure, the deformation resistance of the inner ring layer 2213 is enhanced, the risk of central collapse and deformation of the electrode assembly 22 is reduced, lithium precipitation is effectively reduced, and the service life of the battery cell 20 is prolonged.

In some embodiments, referring to fig. 4, the reinforcement portion 223 partially extends beyond the first winding start end 2215.

The portion of the reinforcing portion 223 beyond the first winding start end 2215 may be wound and arranged in the innermost circumference of the inner circumference layer 2213 to provide a good support for the first segment 2211, and further reduce the risk of central collapse and deformation of the electrode assembly 22.

In this embodiment, since the reinforcing portion 223 partially extends beyond the first winding start end 2215, so that the reinforcing portion 223 covers the whole first segment 2211, the reinforcing portion 223 has a good reinforcing effect on the whole first segment 2211 in the winding direction X, and the whole first segment 2211 has a good deformation resistance.

In some embodiments, referring to fig. 5, an end of the reinforcing portion 223 far from the connection position 2212a along the winding direction X is aligned with the winding start end.

One end of the reinforcing portion 223, which is far from the connecting position 2212a in the winding direction X, is a starting end of the reinforcing portion 223, one end of the reinforcing portion 223, which is located at the connecting position 2212a, is a terminal end, and the reinforcing portion 223 is wound from the starting end to the terminal end in the winding direction X.

In this embodiment, since the end of the reinforcing portion 223 far from the connecting position 2212a is aligned with the first winding start end 2215, so that the reinforcing portion 223 covers the whole first segment 2211, the reinforcing portion 223 has a good reinforcing effect on the whole first segment 2211 in the winding direction X, and the whole first segment 2211 has a good deformation resistance.

In some embodiments, referring to fig. 4 and 5, the second pole piece 222 has a second winding start 2221. The first pole piece 221 includes a third segment 2217, the third segment 2217 is wound from the first winding start end 2215 along the winding direction X to a first alignment position 2217a aligned with the second winding start end 2221, the first alignment position 2217a is adjacent to the second winding start end 2221 and is located outside the second winding start end 2221, and the first segment 2211 forms at least a part of the third segment 2217.

The second winding start end 2221 is an end of the second pole piece 222 near the center of the electrode assembly 22. The second pole piece 222 also has a second winding ending end 2222, and the second pole piece 222 extends from the second winding starting end 2221 to the second winding ending end 2222 along the winding direction X.

First segment 2211 forms at least a portion of third segment 2217, and it is understood that a portion of third segment 2217 can be first segment 2211, or third segment 2217 can be first segment 2211 as a whole. If the third segment 2217 is integrally formed as the first segment 2211, the connecting location 2212a between the first segment 2211 and the second segment 2212 is the first alignment location 2217 a.

Illustratively, the reinforcement 223 is disposed on an inner surface of the third segment 2217.

In this embodiment, the first segment 2211 is formed at least a part of the third segment 2217, that is, the reinforcing portion 223 is disposed on the third segment 2217, since the third segment 2217 is wound from the first winding start end 2215 to the first alignment position 2217a aligned with the second winding start end 2221 along the winding direction X, the second pole piece 222 opposite to the third segment 2217 does not exist on the inner side of the third segment 2217, and the reinforcing portion 223 is disposed on the third segment 2217, the third segment 2217 is not easy to obstruct the transmission of ions (such as lithium ions) between the first pole piece 221 and the second pole piece 222.

In some embodiments, referring to fig. 6, third segment 2217 includes a projection 2218 projecting from second winding start 2221, projection 2218 is wound from first winding start 2215 along winding direction X to a second alignment position 2217b aligned with second winding start 2221, second alignment position 2217b is adjacent to second winding start 2221 and is located inside second winding start 2221, and first segment 2211 forms at least a portion of projection 2218.

When the first pole piece 221 and the second pole piece 222 are unfolded and stacked, the portion of the first pole piece 221 beyond the second winding start end 2221 is the excess section 2218.

In the third segment 2217, one turn of the first pole piece 221 is formed from the second alignment position 2217b to the first alignment position 2217a, that is, the third segment 2217 is wound 360 ° in the winding direction X from the second alignment position 2217b to the first alignment position 2217 a.

The first segment 2211 forms at least a portion of the excess segment 2218, and it is understood that a portion of the excess segment 2218 is the first segment 2211, or the excess segment 2218 is the first segment 2211 as a whole. Beyond the entirety of the first segment 2211, the location 2212a where the first segment 2211 and the second segment 2212 are connected is the second alignment location 2217 b.

In this embodiment, the first segment 2211 forms at least a part of the excess segment 2218, that is, the reinforcement portion 223 is disposed on the excess segment 2218, since the third segment 2217 is wound from the second winding start end 2221 to the second alignment position 2217b aligned with the second winding start end 2221 along the winding direction X, the inner side and the outer side of the excess segment 2218 are not present on the second pole piece 222 opposite to the excess segment 2218, and the reinforcement portion 223 is disposed on the excess segment 2218, so as to further reduce the influence of the reinforcement portion 223 on the ion transmission between the first pole piece 221 and the second pole piece 222. In addition, because first segment 2211 is formed beyond at least a portion of segment 2218, the diameter of each turn in inner turn layer 2213 formed by first segment 2211 is smaller, making it more difficult for the center of electrode assembly 22 to collapse.

In some embodiments, with continued reference to fig. 4-6, the reinforcing portion 223 is wound at least 1 turn along the winding direction X.

The reinforcing portion 223 is formed one turn every 360 ° in the winding direction X from the starting end thereof.

In the present embodiment, the reinforcing part 223 is wound at least 1 turn along the winding direction X, so that the reinforcing part 223 has a good reinforcing effect on the first segment 2211, and the first segment 2211 has a good deformation resistance.

In some embodiments, the reinforcement 223 is wound 1-5 turns in the winding direction X.

The number of windings of the reinforcement 223 may be equal to or greater than the number of windings of the first segment 2211. For example, the number of windings of the reinforcing portion 223 and the number of windings of the first segment 2211 are both 1.5.

In an embodiment where the reinforcing portion 223 partially exceeds the first winding start end 2215, the number of windings of the reinforcing portion 223 may be greater than that of the first segment 2211, for example, the number of windings of the first segment 2211 is 2, the number of windings of the reinforcing portion 223 is 3, and the portion where the reinforcing portion 223 exceeds the first winding start end 2215 is wound for 1 turn in the innermost turn of the inner turn layer 2213.

In this embodiment, the reinforcing portion 223 is wound for 1 to 5 turns along the winding direction X, which not only plays a good role in reinforcing the first segment 2211, but also prevents the length of the reinforcing portion 223 along the winding direction X from being too long, thereby reducing the space occupied by reinforcement and reducing the influence of the reinforcing portion 223 on the energy density of the battery cell 20.

In some embodiments, referring to fig. 7 and 8, fig. 7 is a schematic structural view of the first pole piece 221 provided in some embodiments of the present disclosure after being expanded, and fig. 8 is a schematic structural view of the first pole piece 221 provided in other embodiments of the present disclosure after being expanded, in which the first pole piece 221 includes a first current collector 221a and a first active material layer 221b, the first active material layer 221b is disposed on a surface of the first current collector 221a in the thickness direction Z, and at least one side of the first current collector 221a in the thickness direction Z is provided with a reinforcing portion 223. Referring to fig. 7, the reinforcing portion 223 is disposed on a side of the first active material layer 221b of the first segment 2211 away from the first current collector 221 a; alternatively, referring to fig. 8, the reinforcing portion 223 is disposed between the first active material layer 221b and the first current collector 221a of the first segment 2211.

The first current collector 221a may be provided with the reinforcing portion 223 on at least one side in the thickness direction Z, the first current collector 221a may be provided with the reinforcing portion 223 on one side in the thickness direction Z, and the first current collector 221a may be provided with the reinforcing portions 223 on both sides in the thickness direction Z. In fig. 7 and 8, the first current collector 221a is provided with the reinforcing portions 223 on both sides in the thickness direction Z.

Illustratively, the thickness of the first active material layer 221b of the first segment 2211 is equal to the thickness of the first active material layer 221b of the second segment 2212.

In this embodiment, if the reinforcing portion 223 is disposed on a side of the first active material layer 221b of the first segment 2211 facing away from the first current collector 221a, the reinforcing portion 223 is located on a surface layer of the first segment 2211, so that the reinforcing portion 223 is conveniently disposed on the first segment 2211. If the reinforcing portion 223 is disposed between the first active material layer 221b and the first current collector 221a in the first segment 2211, the reinforcing portion 223 is less likely to hinder the transmission of ions in the first active material layer 221 b.

In some embodiments, with continued reference to fig. 7, the reinforcing portion 223 is a glue layer 2231 disposed on a surface of the first active material layer 221b of the first segment 2211 facing away from the first current collector 221 a.

The adhesive layer 2231 may be a solid layer formed by solidifying a glue applied to the surface of the first active material layer 221b, or may be an adhesive tape or a strip adhered to the surface of the first active material layer 221 b.

In the present embodiment, the reinforcing portion 223 is a glue layer 2231, which is convenient to arrange on the surface of the first active material layer 221 b. The glue layer 2231 is adhered to the surface of the first active material layer 221b, and is not easily separated from the first active material layer 221b, and the reinforcement portion 223 plays a good role in reinforcing the first segment 2211.

It should be noted that in the embodiment where the reinforcing layer is disposed between the first active material layer 221b and the first current collector 221a of the first segment 2211, the reinforcing layer may also be the glue layer 2231.

In some embodiments, referring to fig. 9, fig. 9 is a schematic structural view of the first pole piece 221 after being unfolded according to still other embodiments of the present disclosure, and the reinforcing portion 223 is a second active material layer 2232 coated on the first active material layer 221b of the first segment 2211. The total thickness of the second active material layer 2232 and the first active material layer 221b of the first segment 2211 is greater than the thickness of the first active material layer 221b of the second segment 2212.

The material of the second active material layer 2232 and the material of the first active material layer 221b may be the same or different. If the material of the second active material layer 2232 is the same as that of the first active material layer 221b, the reinforcing portion 223 can be regarded as a portion of the first pole piece 221 in the first section 2211 where the active material layer extends beyond the active material layer in the second section 2212.

Note that the same material for the second active material layer 2232 and the first active material layer 221b means that the components of the second active material layer 2232 and the first active material layer 221b are the same, and the ratio of each component is the same.

In this embodiment, the first segment 2211 is reinforced in such a manner that the total thickness of the second active material layer 2232 and the first active material layer 221b of the first segment 2211 is greater than the thickness of the first active material layer 221b of the second segment 2212, and the implementation is simple and economical. The second active material layer 2232 is coated on the first active material layer 221b, and the second active material layer 2232 and the first active material layer 221b have good integrity, so that the first segment 2211 has good deformation resistance.

In some embodiments, the hardness of the reinforcement 223 is greater than the hardness of the first active material layer 221b of the first segment 2211.

Taking the reinforcing portion 223 as the glue layer 2231, and the glue layer 2231 is solidified by glue, the hardness of the glue layer 2231 formed after the glue is solidified is greater than the hardness of the first active material layer 221b of the first segment 2211.

In the embodiment in which the second active material layer 2232 is the reinforcing portion 223, since the hardness of the reinforcing portion 223 is greater than that of the first active material layer 221b in the first section 2211, the material of the second active material layer 2232 may be different from that of the first active material layer 221b, and the difference in hardness is realized by active material layers of different materials.

In this embodiment, since the hardness of the reinforcing portion 223 is greater than that of the first active material layer 221b of the first segment 2211, the reinforcing portion 223 has better deformation resistance than that of the first active material layer 221b, and the reinforcing portion 223 has a good reinforcing effect on the first segment 2211 to enhance the deformation resistance of the first segment 2211.

In some embodiments, referring to fig. 10, fig. 10 is a schematic structural view of the first pole piece 221 after being expanded according to still other embodiments of the present disclosure, in which the first pole piece 221 includes a first current collector 221a and a first active material layer 221b, and the first active material layer 221b is disposed on a surface of the first current collector 221a in the thickness direction Z. The first current collector 221a of the first section 2211 is not provided with the first active material layer 221b, the surface of the first current collector 221a of the first section 2211 in the thickness direction Z is provided with the reinforcing portion 223, and the hardness of the reinforcing portion 223 is greater than that of the first active material layer 221b of the second section 2212.

It can be understood that, in the present embodiment, the surface of the first current collector 221a of the second segment 2212 in the thickness direction Z is provided with the first active material layer 221b, while the surface of the first current collector 221a of the first segment 2211 in the thickness direction Z is not provided with the first active material layer 221 b.

In this embodiment, the reinforcing portion 223 may be a glue layer 2231, but the glue layer 2231 may be a solid layer formed by solidifying glue applied to the surface of the first current collector 221a, or may be an adhesive tape or a rubber strip adhered to the surface of the first current collector 221 a.

In this embodiment, the reinforcing portion 223 reinforces the first current collector 221a of the first segment 2211, and the hardness of the reinforcing portion 223 is greater than that of the first active material layer 221b of the second segment 2212, so that the deformation resistance of the reinforcing portion 223 and the first current collector 221a of the first segment 2211 as a whole is greater than that of the second segment 2212, thereby achieving the purpose of enhancing the deformation resistance of the inner ring layer 2213.

In some embodiments, referring to fig. 11, fig. 11 is a schematic structural diagram of an electrode assembly 22 according to other embodiments of the present application, in which the electrode assembly 22 further includes a shielding member 225, and the shielding member 225 is disposed on the first pole piece 221 and stacked with the first pole piece 221. The first pole piece 221 further has a first winding end 2216, and one end of the shielding member 225 is aligned with the first winding end 2216 or the shielding member 225 partially extends beyond the first winding end 2216 along the winding direction X.

Illustratively, in fig. 11, the shielding member 225 is partially extended beyond the first winding trailing end 2216 along the winding direction X, and the shielding member 225 is disposed on the inner surface of the first pole piece 221. The guard 225 may be an adhesive tape, strip, or the like affixed to the first pole piece 221.

The shielding member 225 shields the first winding end 2216 of the first pole piece 221, so as to reduce the risk of short circuit caused by the sharp portion of the first winding end 2216 of the first pole piece 221 damaging the isolation film 224.

Of course, a guard 225 may also be provided on the second pole piece 222 to guard the second winding trailing end 2222 of the second pole piece 222.

In some embodiments, with continued reference to fig. 11, electrode assembly 22 is cylindrical in configuration. The electrode assembly 22 is generally cylindrical and may be used with cylindrical cells.

In some embodiments, referring to fig. 12, fig. 12 is a schematic structural diagram of an electrode assembly 22 according to another embodiment of the present disclosure, in which the electrode assembly 22 includes a flat region a and a bent region B connected to the flat region a. The reinforcement 223 is at least partially located at the inflection region B.

Illustratively, the electrode assembly 22 has two bending regions B connected to both ends of the flat region a, and the reinforcing part 223 bypasses the two bending regions B in the winding direction X.

The electrode assembly 22 provided in the present embodiment may be applied to a prismatic battery cell.

In this embodiment, the reinforcing portion 223 is at least partially located in the bending region B, so that the portion of the first segment 2211 located in the bending region B has a good bending resistance, the risk of inward collapse of the pole piece of the bending region B is reduced, and lithium deposition is effectively reduced.

In the embodiment of the present application, the second pole piece 222 may also be provided with a reinforcing portion 223 to reinforce the inner ring layer of the second pole piece 222.

The embodiment of the present application provides a battery cell 20, which includes a case and an electrode assembly 22 provided in any one of the above embodiments, wherein the case is used for accommodating the electrode assembly 22.

The embodiment of the application provides a battery 100, which comprises a box body 10 and a battery cell 20 provided by any one of the above embodiments, wherein the box body 10 is used for accommodating the battery cell 20.

The embodiment of the present application provides an electric device, including the battery 100 provided in any one of the above embodiments.

The powered device may be any of the devices described above that employ battery 100.

In addition, referring to fig. 4, an embodiment of the present application provides a cylindrical electrode assembly, and the cylindrical electrode assembly includes a positive electrode tab, a negative electrode tab, and a separator 224, wherein the positive electrode tab, the separator 224, and the negative electrode tab are sequentially stacked and wound along a winding direction X to form a wound electrode assembly. The negative electrode sheet has a first winding start end 2215, the negative electrode sheet comprises a first section 2211 and a second section 2212 which are continuously arranged along the winding direction X, the first section 2211 is wound along the winding direction X from the first winding start end 2215 to form an inner ring layer 2213, the second section 2212 is wound along the winding direction X from a position 2212a where the second section 2212 is connected with the first section 2211 to form an outer ring layer 2214, and the outer ring layer 2214 is positioned on the outer side of the inner ring layer 2213. Wherein the first segment 2211 is provided with a glue layer 2231, the glue layer 2231 is wound from the first winding start end 2215 to the connecting position 2212a along the winding direction X, the glue layer 2231 is arranged on the inner surface of the first segment 2211, and the glue layer 2231 is used for reinforcing the first segment 2211.

In the electrode assembly 22, the first section 2211 of the negative electrode plate is reinforced by the glue layer 2231, so that the inner ring layer 2213 of the negative electrode plate forms a strong self-supporting structure, the deformation resistance of the inner ring layer 2213 of the negative electrode plate is enhanced, the risk of central collapse and deformation of the electrode assembly 22 is reduced, lithium precipitation is effectively reduced, and the service life of the battery cell 20 is prolonged.

Referring to fig. 13, fig. 13 is a flowchart illustrating a method for manufacturing an electrode assembly 22 according to some embodiments of the present disclosure, where the method for manufacturing an electrode assembly 22 includes:

s100: providing a first pole piece 221 and a second pole piece 222, wherein the polarities of the first pole piece 221 and the second pole piece 222 are opposite;

s200: the first pole piece 221 and the second pole piece 222 are stacked and then wound in the winding direction X to form a wound structure.

The first pole piece 221 has a first winding start end 2215, the first pole piece 221 includes a first segment 2211 and a second segment 2212 continuously arranged along the winding direction X, the first segment 2211 is wound from the first winding start end 2215 along the winding direction X to form an inner ring layer 2213, the second segment 2212 is wound from a position 2212a where the second segment 2211 is connected to form an outer ring layer 2214 along the winding direction X, and the outer ring layer 2214 is located outside the inner ring layer 2213. The first segment 2211 is provided with a reinforcing portion 223, the reinforcing portion 223 is wound to the connecting position 2212a in the winding direction X, and the reinforcing portion 223 is used to reinforce the first segment 2211.

It should be noted that, with respect to the structure of the electrode assembly 22 manufactured by the manufacturing method provided in the foregoing embodiments, reference may be made to the electrode assembly 22 provided in each of the foregoing embodiments, and details are not repeated herein.

Referring to fig. 14, fig. 14 is a schematic block diagram illustrating a manufacturing apparatus for an electrode assembly 22 according to some embodiments of the present disclosure, and a manufacturing apparatus 2000 for an electrode assembly 22 according to some embodiments of the present disclosure is also provided, where the manufacturing apparatus 2000 includes a providing device 2100 and an assembling device 2200.

The apparatus 2100 is provided for providing a first pole piece 221 and a second pole piece 222, the first pole piece 221 and the second pole piece 222 being of opposite polarity. The assembling device 2200 is used for laminating the first pole piece 221 and the second pole piece 222 and then winding them along the winding direction X to form a winding structure.

It should be noted that, with regard to the structure of the electrode assembly 22 manufactured by the manufacturing apparatus 2000 provided in the foregoing embodiments, reference may be made to the electrode assembly 22 provided in each of the foregoing embodiments, and details are not repeated herein.

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 embodiments are merely for illustrating the technical solutions of the present application and are not intended to limit the present application, and those skilled in the art can make various modifications and variations of the present application. 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

1. An electrode assembly comprising first and second opposite polarity pole pieces, the first and second pole pieces being arranged in a stack and wound in a winding direction to form a wound structure;

the first pole piece is provided with a first winding starting end and comprises a first section and a second section which are continuously arranged along the winding direction, the first section is wound along the winding direction from the first winding starting end to form an inner ring layer, the second section is wound along the winding direction from a position where the second section is connected with the first section to form an outer ring layer, and the outer ring layer is positioned on the outer side of the inner ring layer;

the first section is provided with a reinforcing part, the reinforcing part is wound to the connecting position along the winding direction, and the reinforcing part is used for reinforcing the first section.

2. The electrode assembly of claim 1, wherein the reinforcement portion exceeds the first winding start end; or, one end of the reinforcing part far away from the connecting position along the winding direction is aligned with the first winding starting end.

3. The electrode assembly of claim 1, wherein the second tab has a second winding start end;

the first pole piece comprises a third section, the third section is wound from the first winding starting end to a first alignment position aligned with the second winding starting end along the winding direction, the first alignment position is adjacent to the second winding starting end and located on the outer side of the second winding starting end, and the first section forms at least one part of the third section.

4. The electrode assembly of claim 3, wherein the third segment includes an excess segment that exceeds the second winding start end, the excess segment being wound in the winding direction from the first winding start end to a second alignment position aligned with the second winding start end, the second alignment position being adjacent to and inside the second winding start end, the first segment forming at least a portion of the excess segment.

5. The electrode assembly of claim 1, wherein the reinforcement portion is wound at least 1 turn in the winding direction.

6. The electrode assembly according to claim 5, wherein the reinforcing part is wound in the winding direction by 1 to 5 turns.

7. The electrode assembly according to any one of claims 1 to 6, wherein the first electrode sheet includes a first current collector and a first active material layer, the first active material layer being provided on a surface of the first current collector in a thickness direction, the first current collector being provided with the reinforcement portion on at least one side in the thickness direction;

the reinforcing part is arranged on one side, away from the first current collector, of the first active material layer of the first section; or, the reinforcement is disposed between the first active material layer of the first segment and the first current collector.

8. The electrode assembly of claim 7, wherein the reinforcement is a glue layer disposed on a surface of the first active material layer of the first segment facing away from the first current collector.

9. The electrode assembly of claim 7, wherein the reinforcement is a second active material layer applied to the first active material layer of the first segment;

the second active material layer and the first active material layer of the first segment have a total thickness greater than a thickness of the first active material layer of the second segment.

10. The electrode assembly according to claim 7, wherein the hardness of the reinforcing portion is greater than the hardness of the first active material layer of the first segment.

11. The electrode assembly according to any one of claims 1 to 6, wherein the first electrode sheet includes a first current collector and a first active material layer provided on a surface of the first current collector in a thickness direction;

the first section the first mass flow body does not set up the first active material layer, the first section the first mass flow body surface in the thickness direction is provided with the rib, the hardness of rib is greater than the second section the hardness of first active material layer.

12. The electrode assembly of any one of claims 1-6, further comprising a guard disposed on and stacked with the first pole piece;

the first pole piece further has a first winding trailing end, and in the winding direction, one end of the guard member is aligned with or partially beyond the first winding trailing end.

13. The electrode assembly of any of claims 1-6, wherein the electrode assembly is of cylindrical construction.

14. The electrode assembly of any of claims 1-6, wherein the electrode assembly comprises a flat region and a bent region connected to the flat region;

the reinforcement is at least partially located in the bending region.

15. A battery cell, comprising:

the electrode assembly of any one of claims 1-14;

a case for accommodating the electrode assembly.

16. A battery, comprising:

the battery cell of claim 15;

the box is used for accommodating the battery monomer.

17. An electrical device comprising the battery of claim 16.