CN217788494U - Electrode assembly, battery cell, battery and electric equipment - Google Patents

Abstract

The embodiment of the application discloses an electrode assembly, a battery monomer, a battery and electric equipment. The electrode assembly includes: the anode pole piece comprises a plurality of laminated sections and at least one bent section, and the at least one bent section and the laminated sections are arranged at intervals and are connected with each other; at least one composite layer comprising: the cathode plate comprises a cathode plate and two layers of isolation films, wherein the two layers of isolation films are respectively arranged on two surfaces of the cathode plate, and the at least one composite layer and the plurality of laminated sections are alternately laminated along the first direction. The electrode assembly, the single battery, the battery and the electric equipment provided by the embodiment of the application can improve the performance of the electrode assembly.

Description

Electrode assembly, battery cell, battery and electric equipment

Technical Field

The present application relates to the field of batteries, and more particularly, to an electrode assembly, a battery cell, a battery, and an electric device.

Background

Energy conservation and emission reduction are the key points of sustainable development of the automobile industry. Under such circumstances, electric vehicles are an important component of sustainable development of the automobile industry due to their energy saving and environmental protection advantages. In the case of electric vehicles, battery technology is an important factor in the development thereof.

The whole manufacturing process of the battery is long, the process is complex, and the whole manufacturing process comprises a series of processes such as coating, flaking, assembling, laser welding and liquid injection. The processing process of the electrode assembly inside the battery cell is particularly important, and the processing efficiency and performance of the battery cell are directly affected. Therefore, how to improve the processing efficiency and performance of the electrode assembly is a technical problem to be solved urgently.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides an electrode subassembly, battery monomer, battery and consumer, can improve electrode subassembly's performance.

In a first aspect, there is provided an electrode assembly comprising: the anode pole piece comprises a plurality of laminated sections and at least one bent section, and the at least one bent section and the laminated sections are arranged at intervals and are connected with each other; at least one composite layer comprising: the cathode pole piece and the two layers of isolating films are respectively arranged on two surfaces of the cathode pole piece, and the at least one composite layer and the plurality of laminating sections are alternately laminated along the first direction.

Therefore, compared with the traditional electrode assembly, the electrode assembly provided by the embodiment of the application has the advantages that the strength of the cathode pole piece is increased by arranging the composite layer comprising the cathode pole piece and the two layers of isolating films, the phenomenon that the cathode pole piece is folded can be effectively reduced, the dislocation phenomenon of the cathode pole piece can also be reduced, and the performance and the qualified rate of the electrode assembly are improved.

In some embodiments, the two layers of separation films cover two surfaces of the cathode plate respectively, so that at least one layer of separation film is arranged between the cathode plate and different positions of the lamination section to avoid short circuit.

In some embodiments, the edges of the two layers of separator membrane are joined to form a hollow structure for receiving the cathode plate to avoid short circuiting.

In some embodiments, the two opposite side edges of the two layers of isolation films are connected to form the hollow structure with two open ends, and the open end of the hollow structure is parallel to the first direction and perpendicular to the bending section to avoid short circuit.

In some embodiments, an orthographic projection of the composite layer on the laminated segment is located within the laminated segment to avoid lithium deposition.

In some embodiments, the surface of the bending section far away from the composite layer is provided with a notch so as to facilitate bending of the anode pole piece.

In some embodiments, the two layers of separator are the same size and/or material to facilitate processing.

In some embodiments, the electrode assembly further comprises: and the pole piece is arranged on a first end face of the electrode assembly, and the first end face is parallel to the first direction and is perpendicular to the bending section. And the tab is arranged on the first end surface, so that the tab is convenient to process.

In some embodiments, the electrode assembly further comprises: the insulating layer is arranged on the surface, far away from the composite layer, of the first lamination section of the anode pole piece, and the first lamination section is a lamination section comprising the starting end or the ending end of the anode pole piece in the plurality of lamination sections. The anode plate can be effectively protected by arranging the insulating layer.

In a second aspect, a battery cell is provided, including: the electrode assembly of the first aspect or any embodiment of the first aspect.

In a third aspect, a battery is provided, which includes a plurality of battery cells including the electrode assembly of the first aspect or any one of the embodiments of the first aspect.

In a fourth aspect, there is provided an electrical device comprising: a battery comprising the electrode assembly of the first aspect or any one of the embodiments of the first aspect.

In some embodiments, the powered device is a vehicle, a watercraft, or a spacecraft.

Drawings

FIG. 1 is a schematic cross-sectional view of a conventional electrode assembly;

FIG. 2 is a schematic illustration of a vehicle according to one embodiment of the present application;

FIG. 3 is a schematic view of the structure of an electrode assembly according to one embodiment of the present application;

FIG. 4 is a schematic cross-sectional view of an electrode assembly according to one embodiment of the present application;

FIG. 5 is a schematic cross-sectional view of a composite layer according to one embodiment of the present application;

FIG. 6 is another schematic cross-sectional view of an electrode assembly in accordance with an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

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 figures above, 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. It is explicitly and implicitly understood by a person skilled in the art that the embodiments described herein can be combined with 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 the case may be.

The term "and/or" in this application is only one kind of association relationship describing the association object, and means that there may be three kinds of relationships, for example, a and/or B, and 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 components, and in the different embodiments, detailed descriptions of the like components are omitted 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 "plurality" in the present application means two or more (including two), and similarly, "plural" means two or more (including two) and "plural" means two or more (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 charge or discharge of battery cells.

The battery monomer comprises an electrode assembly and electrolyte, wherein the electrode assembly consists of a cathode pole piece, an anode pole piece and a separation film. The battery cell mainly depends on metal ions to move between a cathode pole piece and an anode pole piece to work. The cathode pole piece comprises a cathode current collector and a cathode active substance layer, wherein the cathode active substance layer is coated on the surface of the cathode current collector, the cathode current collector which is not coated with the cathode active substance layer protrudes out of the cathode current collector which is coated with the cathode active substance layer, and the cathode current collector which is not coated with the cathode active substance layer is used as a cathode tab. Taking a lithium ion battery as an example, the material of the cathode current collector may be aluminum, and the cathode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, or the like. The anode plate comprises an anode current collector and an anode active substance layer, wherein the anode active substance layer is coated on the surface of the anode current collector, the anode current collector which is not coated with the anode active substance layer protrudes out of the anode current collector which is coated with the anode active substance layer, and the anode current collector which is not coated with the anode active substance layer is used as an anode tab. The material of the anode current collector may be copper, and the anode active material may be carbon or silicon, etc. In order to ensure that the high current can be passed without fusing, a plurality of cathode tabs are laminated together, and a plurality of anode tabs are laminated together. The material of the isolation film may be polypropylene (PP) or Polyethylene (PE). 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.

Conventional processes typically suffer from a number of drawbacks for laminated electrode assemblies. Fig. 1 shows a schematic cross-sectional view of a conventional laminated electrode assembly 100, which may be parallel to a plane in which tabs of the electrode assembly 100 are located, for example. As shown in fig. 1, the electrode assembly 100 includes: an anode tab 101, a plurality of cathode tabs 102, a first separator 103, and a second separator 104. Specifically, the anode tab 101 includes a plurality of stacked segments 1011 and a plurality of bent segments 1012, wherein each bent segment 1012 is used for connecting two adjacent stacked segments 1011, and the plurality of cathode tabs 102 and the plurality of stacked segments 1011 are alternately stacked along a first direction X, and the first direction X is parallel to the cross-sectional direction.

In addition, the electrode assembly 100 may include the first and second separators 103 and 104 in synchronization with the arrangement of the anode tab 101 to prevent a short circuit between the anode tab 101 and the plurality of cathode tabs 102.

In this electrode assembly 100, the anode tab 101 is continuous with the two separators 103 and 104 and can be processed simultaneously; the separation of the cathode sheets 102 from each other can present a number of problems during processing. For example, each cathode sheet 102 is easily subjected to a corner folding problem during the stacking process, for example, during the processing process, the cathode sheets may need to be pressed by a plurality of pressing rollers, the strength of each cathode sheet 102 is limited, and the corner folding phenomenon is easily generated, thereby affecting the performance of the electrode assembly 100 and even causing the failure rate of the electrode assembly 100; moreover, the strength of a single cathode plate 102 is small, the thickness is thin, and the cathode plate 102 is easily dislocated due to vibration during the processing, which also affects the performance of the electrode assembly 100 and even increases the rejection rate of the electrode assembly 100.

Accordingly, embodiments of the present application provide an electrode assembly, a battery cell, a battery and an electric device, which can solve the above problems. The electrode assembly comprises an anode pole piece and at least one composite layer, wherein the anode pole piece comprises a plurality of laminated sections and at least one bent section, and the at least one bent section and the laminated sections are arranged at intervals and are connected with each other; the composite layer includes: the cathode pole piece and the two layers of isolating films are respectively arranged on two surfaces of the cathode pole piece, and the at least one composite layer and the plurality of laminating sections are alternately laminated along the first direction X. Thus, compared with the conventional electrode assembly 100, the electrode assembly of the embodiment of the present application increases the strength of the cathode sheet by providing the composite layer including the cathode sheet and the two layers of the separation films, and can effectively reduce the corner folding phenomenon of the cathode sheet, reduce the dislocation phenomenon of the cathode sheet, and improve the performance and the yield of the electrode assembly.

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

The electric device can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool 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 extending vehicle and the like; spacecraft include aircraft, rockets, space shuttles, spacecraft, and the like; 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.

For example, as shown in fig. 2, which is a schematic structural diagram of a vehicle 1 according to an embodiment of the present disclosure, the vehicle 1 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 an extended range automobile. The vehicle 1 may be provided with a motor 40, a controller 30 and a battery 10, the controller 30 being configured to control the battery 10 to supply power to the motor 40. For example, the battery 10 may be provided at the bottom or the head or tail of the vehicle 1. The battery 10 may be used for power supply of the vehicle 1, for example, the battery 10 may be used as an operation power supply of the vehicle 1 for a circuit system of the vehicle 1, for example, for power demand for operation at the start, navigation, and running of the vehicle 1. In another embodiment of the present application, the battery 10 may be used not only as an operation power source of the vehicle 1 but also as a driving power source of the vehicle 1, instead of or in part replacing fuel or natural gas to provide driving power for the vehicle 1.

The battery 10 may include a case having a hollow structure inside, which may be used to accommodate a plurality of battery cells. The number of cells in the battery 10 may be set to any number according to different power requirements. A plurality of battery cells may be connected in series, parallel, or series-parallel to achieve greater capacity or power. Since the number of battery cells included in each battery 10 may be large, the battery cells may be arranged in groups for convenience of installation, each group of the battery cells constituting a battery module. The number of the battery cells included in the battery modules is not limited, the battery modules may be provided with blocks as required, and the battery modules may be connected in series, parallel, or series-parallel.

Optionally, the battery 10 may also include other structures, which are not described in detail herein. For example, the battery 10 may further include a bus member for achieving electrical connection between the plurality of battery cells, such as parallel connection or series-parallel connection. Specifically, the bus member may achieve electrical connection between the battery cells by connecting electrode terminals of the battery cells. Further, the bus bar member may be fixed to the electrode terminals of the battery cells by welding. The electric energy of the plurality of battery cells can be further led out through the box body by the conductive mechanism.

The battery cell of the embodiment of the present application may include an outer case and an inner electrode assembly. The case may have a hollow structure for receiving the electrode assembly. The battery cell may be provided with one or more electrode assemblies according to actual applications. The electrode assembly is a component of the battery cell in which electrochemical reactions occur. The electrode assembly may be a cylinder, a rectangular parallelepiped, or the like, and the shape of the case of the battery cell may be correspondingly set according to the shape of the electrode assembly.

For example, fig. 3 shows a schematic structural diagram of the electrode assembly 2 according to the embodiment of the present application, and fig. 3 exemplifies two electrode assemblies 2. As shown in fig. 3, the electrode assembly 2 includes a tab 202 and a main portion 201 connected thereto, wherein the main portion 201 may include a cathode tab and an anode tab, and the tab 202 of the electrode assembly 2 may include a cathode tab 2021 and an anode tab 2022. Specifically, the main body part 201 may be formed by laminating or winding a cathode sheet coated with a cathode active material layer and an anode sheet coated with an anode active material layer; the cathode tab 2021 may be formed by laminating a portion protruding from the cathode plate and not coated with the cathode active material layer, and the anode tab 2022 may be formed by laminating a portion protruding from the anode plate and not coated with the anode active material layer.

Alternatively, with respect to a plurality of electrode assemblies 2 included in the battery cell, the tabs 202 of the plurality of electrode assemblies 2 may be connected. As shown in fig. 3, the cathode tabs 2021 of the two electrode assemblies 2 may be electrically connected to each other, and the anode tabs 2021 of the two electrode assemblies 2 may also be electrically connected to each other, so that the plurality of electrode assemblies 2 include one cathode tab 2021 and one anode tab 2022, respectively, but the embodiment of the present application is not limited thereto.

The battery cell of the embodiment of the application is further provided with an electrode terminal, and the electrode terminal is used for being electrically connected with the electrode assembly 2 so as to output the electric energy of the battery cell. The electrode terminals may include a cathode electrode terminal for electrical connection with the cathode tab 2021 and an anode electrode terminal for electrical connection with the anode tab 2022. The cathode electrode terminal and the cathode tab 2021 may be directly connected or indirectly connected, and the anode electrode terminal and the anode tab 2022 may be directly connected or indirectly connected. Illustratively, the cathode electrode terminal is electrically connected to the cathode tab 2021 via a connecting member, and the anode electrode terminal is electrically connected to the anode tab 2022 via a connecting member.

It should be understood that for ease of illustration, the present embodiment defines three mutually perpendicular directions for the electrode assembly 2 shown in fig. 3, including a first direction X, a second direction Y, and a third direction Z. Specifically, as shown in fig. 3, the tab 202 in the embodiment of the present application may be disposed on any one end surface of the electrode assembly 2, for example, the pole piece 202 may be disposed on a first end surface 203 of the electrode assembly 2, and a direction perpendicular to the first end surface 203 where the tab 202 is disposed is defined as a third direction Z, for example, the third direction Z may be regarded as a height direction of the electrode assembly 2. The first direction X and the second direction Y of the embodiment of the present application are both perpendicular to the third direction, or the first direction X and the second direction Y are both parallel to the first end surface 203. Wherein the first direction X is defined as a thickness direction of each electrode assembly 2 and the second direction Y is a length direction of the electrode assembly 2. Alternatively, when the battery cell of the embodiment of the present application includes a plurality of electrode assemblies 2, the plurality of electrode assemblies 2 may be arranged in the first direction X, the second direction Y, or the third direction Z, for example, fig. 3 illustrates that two electrode assemblies 2 are arranged in the first direction X, but the embodiment of the present application is not limited thereto.

The electrode assembly 2 according to the embodiment of the present application will be described in detail with reference to the accompanying drawings. Fig. 4 to the drawings show a schematic cross-sectional view of an electrode assembly 2 according to an embodiment of the present application, for example, the electrode assembly 2 shown in fig. 4 may be a cross-sectional view of any one of the electrode assemblies 2 shown in fig. 3, and specifically may be a cross-sectional view of the main portion 201 of any one of the electrode assemblies 2 shown in fig. 3. The cross section shown in fig. 4 is a plane perpendicular to the direction of the end faces of the electrode assembly 2 where the tabs 202 are located, i.e., the cross section is perpendicular to the third direction Z.

As shown in fig. 4, the electrode assembly 2 of the embodiment of the present application includes: the anode piece 21, the anode piece 21 includes a plurality of stacked segments 211 and at least one bent segment 212, the at least one bent segment 212 and the plurality of stacked segments 211 are arranged at intervals and connected to each other; at least one composite layer 22, the composite layer 22 comprising: the cathode plate 221 and two layers of separation films 222, the two layers of separation films 222 are respectively disposed on two surfaces of the cathode plate 221, and the at least one composite layer 22 and the plurality of lamination sections 211 are alternately laminated in the first direction X.

It should be understood that the electrode assembly 2 of the embodiment of the present application is stacked in the first direction X, and the first end surface 203 of the electrode assembly 2 where the tabs 202 are located is generally parallel to the first direction X; in addition, considering that the anode tab 21 has the bent section 212, the bent section 212 is not provided with the tab 202, and therefore, the first end surface 203 is a plane perpendicular to the bent section 212.

It should be understood that each of the two layers of the separation film 222 in the embodiment of the present application may be used to separate the cathode sheet 221 and the anode sheet 21, and the separation film 222 may also prevent the cathode sheet 221 and the anode sheet 21 from being shorted and short-circuited.

The anode plate 21 of the electrode assembly 2 of the embodiment of the present application is continuous, and includes a plurality of stacked segments 211 and at least one bent segment 212, which are arranged at intervals, that is, along the extending direction of the anode plate 21, one bent segment 212 is arranged between every two adjacent stacked segments 211, and one stacked segment 211 is arranged between every two adjacent bent segments 212, so as to form the laminated electrode assembly 2 as shown in fig. 4. It is to be understood that the electrode assembly 2 may include one or more bending sections 212 for connecting the plurality of stacking sections 211. For convenience of description, the present application mainly takes the anode tab 21 including a plurality of stacked segments 211 and a plurality of bent segments 212 as an example, but the present application is not limited thereto.

In the embodiment of the present application, the electrode assembly 2 includes one or more composite layers 22, and if the electrode assembly 2 includes a plurality of composite layers 22, the plurality of composite layers 22 are discontinuous, and the plurality of composite layers 22 and the plurality of lamination sections 211 are alternately stacked, that is, one lamination section 211 is disposed between every two adjacent composite layers 22 and one composite layer 22 is disposed between every two adjacent lamination sections along the first direction X. In the present embodiment, for convenience of explanation, the electrode assembly 2 includes a plurality of composite layers 22, but the present embodiment is not limited thereto.

In the embodiment of the present application, two layers of isolation films 222 are respectively disposed on two surfaces of the cathode plate 22, where the two surfaces are the surfaces of the cathode plate 221 perpendicular to the thickness direction of the cathode plate 221. As shown in fig. 4, the cathode plate 221 of the present embodiment is a sheet structure, and the cathode plate 221 has two surfaces disposed oppositely, where the two surfaces are perpendicular to the thickness direction of the cathode plate 221, that is, the two surfaces are the upper surface and the lower surface of the cathode plate 221 in fig. 4. Two separators 222 are respectively disposed on the upper and lower surfaces of the cathode plate 221.

Therefore, compared with the conventional electrode assembly 100, the electrode assembly 2 of the embodiment of the present application has the advantages that the composite layer 22 including the cathode plate 221 and the two layers of separators 222 is provided, so that the strength of the cathode plate 221 is increased, the phenomenon that the cathode plate 221 is folded can be effectively reduced, the phenomenon that the cathode plate 221 is dislocated can also be reduced, and the performance and the yield of the electrode assembly 2 are improved.

In some embodiments, the surface of the bending section 212 away from the composite layer 22 is provided with an indentation 2121 to facilitate bending of the anode sheet 21. Specifically, the notch 2121 may extend along the third direction X, so as to bend the anode sheet 21 in different areas of the third direction X simultaneously, thereby avoiding the inclination or misalignment of the anode sheet 21.

In the embodiment of the present application, the electrode assembly 2 further includes: and the insulating layer 23 is arranged on the surface of the first laminated section 2111 of the anode pole piece 21, which is far away from the composite layer 22, wherein the first laminated section 2111 is a laminated section including the starting end 213 or the ending end 214 of the anode pole piece 21 in the plurality of laminated sections 211. Specifically, as shown in fig. 4, the first stacked segment 2111 of the embodiment of the present application may be a stacked segment including the starting end 213 of the anode tab 21, such that one surface of the first stacked segment 2111 faces the composite layer 22 and one surface is away from the composite layer 22, and therefore, an insulating layer 23 may be provided on the surface of the first stacked segment 2111 away from the composite layer 22 to protect the electrode assembly 2, for example, the first stacked segment 2111 may be protected. Similarly, the first stacked segment 2111 may also be a stacked segment including the trailing end 214 of the anode tab 21, such that one surface of the first stacked segment 2111 faces the composite layer 22 and one surface is away from the composite layer 22, and thus an insulating layer 23 may be provided on the surface of the first stacked segment 2111 away from the composite layer 22 to protect the electrode assembly 2, for example, the first stacked segment 2111.

It should be understood that the material of the insulating layer 23 of the embodiment of the present application may be set according to the actual application. For example, the material of the insulating layer 23 may be the same as that of the two-sided isolation film 222 of the embodiment of the present application, so as to facilitate processing.

Optionally, the electrode assembly 2 of the embodiment of the present application may further include a run-in glue, which may be used to form at least a portion of an outer surface of the electrode assembly 2 as the electrode assembly 2, so as to fix the electrode assembly 2, avoid the problem of loose collapse of the electrode assembly 2, and increase the structural strength and stability of the electrode assembly 2. Wherein, the material of this ending glue can set up according to practical application.

The composite layer 22 of the embodiment of the present application will be described in detail with reference to the drawings. Fig. 5 shows a schematic cross-sectional view of the composite layer 22 according to the embodiment of the present application, for example, the composite layer 22 shown in fig. 5 may be any one of the composite layers 22 in fig. 4, and the cross-section of fig. 5 and the cross-section of fig. 4 may be located on the same plane. Fig. 6 shows a schematic cross-sectional view of the electrode assembly 2 of the embodiment of the present application, the cross-section being a cross-section perpendicular to the stacking direction of the electrode assembly 2, for example, the cross-section being perpendicular to the first direction X, and the cross-section shown in fig. 5 being perpendicular to the cross-section shown in fig. 4.

It should be understood that, as shown in fig. 4 to 6, the two-layer separation film 222 of the embodiment of the present application includes a first separation film 2221 and a second separation film 2222, and the size and material of the two-layer separation film 222 may be set according to practical applications; the two layers of the isolation films 222 may be made of the same material or different materials, and the two layers of the isolation films 222 may have the same or different sizes. For example, the two separators 222 may be formed of the same material and have the same size, so as to facilitate the processing and improve the processing efficiency of the electrode assembly 2. The two separation films 222 having the same size may mean that the two separation films 222 have the same size in any direction, for example, the two separation films 222 have the same thickness in the first direction X, the same length in the second direction Y, and the same length in the third direction Z. And the two layers of the separation film 222 having different sizes may mean: there is at least one direction in which the two layers of separator 222 are different in size. For convenience of illustration, the two isolation films 222 have the same size in the present embodiment, but the present embodiment is not limited thereto.

In the embodiment of the present application, as shown in fig. 4 to 6, two layers of isolation films 222 respectively cover two surfaces of the cathode plate 221, so that at least one layer of isolation film 222 of the two layers of isolation films 222 is disposed between different positions of the lamination section 211 and the cathode plate 221 to avoid short circuit. Specifically, the area of each of the two isolation films 222 is greater than or equal to the area of the cathode sheet 221, so that the isolation film 222 can cover the cathode sheet 221, that is, an area of the surface of the cathode sheet 221 is not exposed, so as to avoid short circuit caused by overlapping of the cathode sheet 221 and the lamination section 211 of the anode sheet 21. For example, in fig. 6, the area of the two layers of isolation films 222 is larger than the area of the cathode sheet 221, so as to effectively avoid short circuit caused by overlapping of the cathode sheet 221 and the lamination section 211 of the anode sheet 21.

In the present embodiment, as shown in fig. 4 to 6, the edges of the two layers of the separation film 222 are connected to form a hollow structure for accommodating the cathode sheet 221 to avoid short circuit. Specifically, edges of two separation films 222 are connected, that is, at least one side edge of the first separation film 2221 is connected to at least one corresponding side edge of the second separation film 2222, for example, in the case of a rectangular separation film 222, three side edges of the first separation film 2221 and the second separation film 2222 may be connected, so that a hollow structure is formed between the two separation films 222. Thus, when the cathode plate 221 is located in the hollow structure, the unconnected side of the first separator 2221 and the second separator 2222 can be used to expose the cathode tab 2022 connected to the cathode plate 221; different areas of the cathode plate 221 are wrapped by at least one of the two layers of isolation films 222, so that the two surfaces of the cathode plate 221 facing the stacking section 211 and the stacking section 211 are not in lap joint and short circuit, and meanwhile, the side of the cathode plate 221 facing the bending section 212 and the bending section 212 are not in lap joint and short circuit, thereby further ensuring the performance of the electrode assembly 2.

For another example, two opposite side edges of the two layers of isolation films 222 are connected to form a hollow structure with two open ends, and the open end of the hollow structure is parallel to the first direction X and perpendicular to the bending section 212. Specifically, still taking a rectangular separator 222 as an example, two side edges of the first separator 2221 and two corresponding side edges of the second separator 2222 may be connected together, so that a hollow structure having two open ends is formed between the two separator 222, the two open ends are oppositely arranged, and both open ends are parallel to the cross section shown in fig. 5, or the two open ends are parallel to the first end face 203 where the cathode tab 2022 is located. Thus, when the cathode plate 221 is located in the hollow structure, both unconnected sides of the first isolating membrane 2221 and the second isolating membrane 2222 can be used to expose the cathode tab 2022 connected to the cathode plate 221, which is more convenient for processing; meanwhile, different areas of the cathode plate 221 are wrapped by at least one of the two layers of isolation films 222, so that the two surfaces of the cathode plate 221 facing the stacking section 211 and the stacking section 211 cannot be in lap joint and short circuit, and meanwhile, the side of the cathode plate 221 facing the bending section 212 and the bending section 212 cannot be in lap joint and short circuit, thereby further ensuring the performance of the electrode assembly 2.

In the present embodiment, as shown in fig. 4 to 6, the orthographic projection of the composite layer 22 on the laminated section 211 is located within the laminated section 211 to avoid lithium deposition. Specifically, the area of the composite layer 22 is smaller than or equal to the area of the lamination section 211, so that in the electrode assembly 2, the orthographic projection of the composite layer 22 on the lamination section 211 can be located in the lamination section 211, that is, the surface of the composite layer 22 does not exceed the range of the lamination section 211, that is, the cathode pole piece 221 of the composite layer 22 can be prevented from exceeding the range of the lamination section 211 of the anode pole piece 21, and thus lithium deposition can be prevented.

Therefore, the electrode assembly 2 of the embodiment of the present application includes an anode tab 21 and at least one composite layer 22, wherein the anode tab 21 includes a plurality of lamination sections 211 and at least one bending section 212, and the at least one bending section 212 is spaced apart from the plurality of lamination sections 211 and connected to each other; the composite layer 22 includes: the cathode plate 221 and two layers of separation films 222, the two layers of separation films 222 are respectively disposed on two surfaces of the cathode plate 221, and the at least one composite layer 22 and the plurality of lamination sections 211 are alternately laminated in the first direction X. Thus, compared with the conventional electrode assembly 100, the electrode assembly 2 of the embodiment of the present application increases the strength of the cathode plate 221 by providing the composite layer 22 including the cathode plate 221 and the two layers of separators 222, so as to effectively reduce the corner folding phenomenon of the cathode plate 221, reduce the dislocation phenomenon of the cathode plate 221, and improve the performance and yield of the electrode assembly 2.

While the application has been described with reference to a preferred embodiment, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the application. In particular, the technical features mentioned in the embodiments can be combined in any way as long as there is no structural conflict. The present application is not intended to be limited to the particular embodiments disclosed herein but is to cover all embodiments that may fall within the scope of the appended claims.

Claims (12)

1. An electrode assembly, comprising:

the anode pole piece comprises a plurality of laminated sections and at least one bent section, and the at least one bent section and the laminated sections are arranged at intervals and are connected with each other;

at least one composite layer, the composite layer comprising: the composite layer comprises a cathode pole piece and two layers of isolation films, wherein the two layers of isolation films are respectively arranged on two surfaces of the cathode pole piece, and the at least one composite layer and the plurality of laminated sections are alternately laminated along a first direction.

2. The electrode assembly according to claim 1, wherein the two separators respectively cover both surfaces of the cathode sheet such that at least one of the two separators is disposed between the cathode sheet and the laminated segment at different positions.

3. The electrode assembly according to claim 2, wherein edges of the two separators are connected to form a hollow structure for receiving the cathode sheet.

4. The electrode assembly according to claim 3, wherein the two opposite side edges of the two separators are connected to form the hollow structure having both ends open, and the open end of the hollow structure is parallel to the first direction and perpendicular to the bending section.

5. The electrode assembly of any of claims 1-4, wherein an orthographic projection of the composite layer on the lamination section is located within the lamination section.

6. The electrode assembly of any one of claims 1 to 4 wherein the surface of the bend remote from the composite layer is provided with a score.

7. The electrode assembly according to any one of claims 1 to 4, wherein the two separators are the same in size and/or material.

8. The electrode assembly of any one of claims 1 to 4, further comprising:

and the pole piece is arranged on a first end face of the electrode assembly, and the first end face is parallel to the first direction and is perpendicular to the bending section.

9. The electrode assembly of any one of claims 1 to 4, further comprising:

the insulating layer is arranged on the surface, far away from the composite layer, of the first lamination section of the anode pole piece, and the first lamination section is a lamination section comprising the starting end or the ending end of the anode pole piece in the plurality of lamination sections.

10. A battery cell, comprising:

an electrode assembly as claimed in any one of claims 1 to 9.

11. A battery, comprising:

a plurality of battery cells comprising the electrode assembly of any one of claims 1-9.

12. An electrical device, comprising:

a battery comprising the electrode assembly of any one of claims 1 to 9, the battery being for providing electrical energy.

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