CN117317139A

CN117317139A - Method and apparatus for preparing electrode assembly

Info

Publication number: CN117317139A
Application number: CN202210711310.9A
Authority: CN
Inventors: 唐代春; 黄玉平; 喻鸿钢; 马云建
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2022-06-22
Filing date: 2022-06-22
Publication date: 2023-12-29

Abstract

The embodiment of the application discloses a method and equipment for preparing an electrode assembly. The method comprises the following steps: compounding a cathode plate and two layers of isolating films to obtain a compound layer, wherein the two layers of isolating films are respectively arranged on two surfaces of the cathode plate; the method comprises alternately stacking at least one composite layer and a plurality of stacked sections of an anode electrode sheet along a first direction to obtain the electrode assembly, wherein the anode electrode sheet comprises the stacked sections and at least one bending section, and the bending section and the stacked sections are arranged at intervals and are connected with each other. The method and the device for preparing the electrode assembly can improve the processing efficiency of the electrode assembly.

Description

Method and apparatus for preparing electrode assembly

Technical Field

The present application relates to the field of batteries, and more particularly, to a method and apparatus for preparing an electrode assembly.

Background

Energy conservation and emission reduction are key to sustainable development of the automobile industry. In this case, the electric vehicle is an important component for sustainable development of the automobile industry due to the advantage of energy conservation and environmental protection. For electric vehicles, battery technology is an important factor for development.

The whole manufacturing flow of the battery is long, and the process is complex, and comprises a series of procedures of coating, flaking, assembling, laser welding, liquid injection and the like. The processing process of the internal electrode assembly of the battery cell is particularly important, and the processing efficiency and performance of the battery cell can be directly affected. Therefore, how to improve the processing efficiency and performance of the electrode assembly is a technical problem to be solved at present.

Disclosure of Invention

The embodiment of the application provides a method and equipment for preparing an electrode assembly, which can improve the processing efficiency of the electrode assembly.

In a first aspect, there is provided a method of preparing an electrode assembly, the method comprising: compounding a cathode plate and two layers of isolating films to obtain a compound layer, wherein the two layers of isolating films are respectively arranged on two surfaces of the cathode plate; the method comprises alternately stacking at least one composite layer and a plurality of stacked sections of an anode electrode sheet along a first direction to obtain the electrode assembly, wherein the anode electrode sheet comprises the stacked sections and at least one bending section, and the bending section and the stacked sections are arranged at intervals and are connected with each other.

Therefore, compared with the traditional processing process of the electrode assembly, the method for preparing the electrode assembly combines the cathode pole piece and the two layers of isolating films to form the composite layer, so that the strength of the cathode pole piece is increased, the phenomenon that the angle of the cathode pole piece is folded can be effectively reduced, the phenomenon that the cathode pole piece is misplaced can be reduced, and the performance and the qualification rate of the electrode assembly are improved.

In some embodiments, the compounding of the cathode sheet and the two separator films to obtain a composite layer comprises: cutting a cathode pole piece assembly into a plurality of cathode pole pieces, arranging the plurality of cathode pole pieces between two isolating membrane assemblies at intervals, and performing extrusion and thermal compounding treatment to obtain a composite assembly; cutting the composite assembly to obtain at least one of the composite layers.

Compared with the condition that a cathode pole piece is fed independently in a traditional electrode assembly, the embodiment of the application stacks the cathode pole piece and the two layers of isolating films after being processed into the composite layer, so that the electrode assembly is formed, the strength of the composite layer is high, the phenomenon that the angle of folding occurs to the cathode pole piece can be effectively reduced, the phenomenon that the cathode pole piece is misplaced can be reduced, and the performance and the qualification rate of the electrode assembly are improved.

In some embodiments, the trimming the composite assembly to obtain at least one of the composite layers comprises: and cutting the two isolating film assemblies in the composite assembly along the interval position among the cathode plates so as to obtain at least one composite layer. The defect of the cathode plate with the preset size caused by cutting the cathode plate is avoided, and the energy density of the battery cell formed by the electrode assembly is further influenced.

In some embodiments, the two-layer separator assembly covers two surfaces of the plurality of cathode pole pieces, respectively, to avoid shorting.

In some embodiments, the disposing a plurality of the cathode sheets between two separator assemblies at a distance from each other, and performing extrusion and thermal compounding processes to obtain a composite assembly, includes: arranging a plurality of cathode pole pieces between two isolating membrane assemblies at intervals, and performing extrusion and thermal compounding treatment to obtain an initial assembly; and carrying out hot melting treatment on the two isolating membrane assemblies in the initial assembly along the periphery of each cathode plate so as to obtain the composite assembly, wherein the composite assembly comprises a plurality of hollow structures, and each hollow structure is used for accommodating the cathode plate.

After the hot melting treatment, the cathode pole piece can be limited within a certain range, and the movement of the cathode pole piece can be limited, so that the dislocation of the cathode pole piece in the subsequent processing is effectively avoided.

In some embodiments, the method further comprises: performing quality test on the composite layer; and determining the qualified composite layer according to the test result of the composite layer, wherein the electrode assembly comprises the qualified composite layer.

The quality of the composite layer can be detected by testing the composite layer through the testing device, unqualified composite layers can be filtered and eliminated in time, and the qualified composite layers are used for processing electrode assemblies, so that the qualification rate of the electrode assemblies is improved.

In some embodiments, the quality testing of the composite layer comprises: and carrying out a Hipot test on the composite layer to determine the voltage-withstanding insulation effect of the composite layer.

In some embodiments, the alternately stacking the at least one composite layer and the plurality of stacked segments of the anode electrode sheet along the first direction comprises: a plurality of composite layers are alternately and misplaced on the two surfaces of the anode pole piece, so that two adjacent composite layers are respectively positioned on the two surfaces of the anode pole piece, the plurality of laminated sections are areas of the anode pole piece corresponding to the plurality of composite layers, and the bending section is an area between the two adjacent laminated sections of the anode pole piece; and bending the bending section so that a plurality of the composite layers and a plurality of the lamination sections are alternately laminated along the first direction, thereby obtaining the laminated electrode assembly.

In some embodiments, the plurality of composite layers are alternately and dislocating disposed on two surfaces of the anode pole piece, so that two adjacent composite layers are respectively located on two surfaces of the anode pole piece, including: a plurality of nicks are alternately and misplaced on the two surfaces of the anode pole piece, two adjacent nicks in the plurality of nicks are respectively positioned on the two surfaces of the anode pole piece, and the plurality of nicks are respectively positioned on a plurality of bending sections; a plurality of composite layers are alternately and misplaced on the two surfaces of the anode pole piece, and the composite layers are positioned between the two adjacent nicks; the bending section to enable the plurality of composite layers and the plurality of laminated sections to be alternately laminated along the first direction comprises the following steps: the plurality of bending sections are bent at the plurality of nicks so that the plurality of composite layers and the plurality of laminated sections are alternately laminated along the first direction.

Therefore, due to the fact that the anode pole piece is provided with the scores, the anode pole piece is easy to bend at the multiple scores under the action of gravity, and the scores on different surfaces can further enable the bending directions of the anode pole piece to be different, and then the laminated electrode assembly is formed.

In some embodiments, the method further comprises: an insulating layer is disposed on a surface of a first lamination section of the anode electrode sheet of the electrode assembly, which is a lamination section including a start end or a junction end of the anode electrode sheet, from among the plurality of lamination sections, and is away from the composite layer. By arranging the insulating layer, the anode plate can be effectively protected.

In a second aspect, there is provided an apparatus for preparing an electrode assembly, comprising: the composite device is used for compositing the cathode pole piece and two layers of isolating films to obtain a composite layer, and the two layers of isolating films are respectively arranged on the two surfaces of the cathode pole piece; lamination means for alternately laminating at least one of the composite layers and a plurality of lamination sections of an anode electrode sheet including the plurality of lamination sections and at least one bending section disposed at a distance from the plurality of lamination sections and connected to each other in a first direction to obtain the electrode assembly.

In some embodiments, the composite device comprises: the first cutter is used for cutting the cathode pole piece assembly into a plurality of cathode pole pieces, and the first press roll is used for extruding the plurality of cathode pole pieces and the two isolation film assemblies when the plurality of cathode pole pieces are arranged between the two isolation film assemblies at intervals and pass through the first press roll; the heating component is used for carrying out thermal compounding treatment on the plurality of cathode pole pieces passing through the first compression roller and the two isolating membrane components so as to obtain a compound component; and a second cutter for cutting the composite assembly to obtain at least one composite layer.

In some embodiments, the second cutter is for: and cutting the two isolating film assemblies in the composite assembly along the interval position among the cathode plates so as to obtain at least one composite layer.

In some embodiments, the two-layer separator assembly covers two surfaces of the plurality of cathode pole pieces, respectively.

In some embodiments, the heating component is further configured to: and carrying out hot melting treatment on the two isolating membrane assemblies subjected to the thermal compounding treatment along the periphery of each cathode plate so as to obtain a composite assembly, wherein the composite assembly comprises a plurality of hollow structures, and each hollow structure is used for accommodating the cathode plate.

In some embodiments, the apparatus further comprises: test device, this test device is used for: performing quality test on the composite layer; and determining the qualified composite layer according to the test result of the composite layer, wherein the electrode assembly comprises the qualified composite layer.

In some embodiments, the test device is for: the composite layer was subjected to a Hipot test.

In some embodiments, the lamination device is for: a plurality of composite layers are alternately and misplaced on the two surfaces of the anode pole piece, so that two adjacent composite layers are respectively positioned on the two surfaces of the anode pole piece, the plurality of laminated sections are areas of the anode pole piece corresponding to the plurality of composite layers, and the bending section is an area between the two adjacent laminated sections of the anode pole piece; the bending section is bent so that a plurality of the composite layers and a plurality of the laminated sections are alternately laminated along the first direction.

In some embodiments, the lamination device comprises: the notch component is used for alternately and misplaced arranging a plurality of notches on the two surfaces of the anode pole piece, wherein two adjacent notches in the plurality of notches are respectively positioned on the two surfaces of the anode pole piece, and the plurality of notches are respectively positioned on a plurality of bending sections; the lamination device is used for: and a plurality of composite layers are alternately and misplaced on the two surfaces of the anode pole piece, the composite layers are positioned between the two adjacent nicks, and the plurality of bending sections are bent at the nicks so as to enable the composite layers and the lamination layers to be alternately laminated along the first direction.

In some embodiments, the apparatus further comprises: and an insulation processing part for providing an insulation layer on a surface of a first lamination section of the anode sheet of the electrode assembly, which is a lamination section including a start end or a junction end of the anode sheet, from the composite layer.

Drawings

Fig. 1 is a schematic view of a conventional process electrode assembly;

fig. 2 is a schematic cross-sectional view of a conventional electrode assembly;

FIG. 3 is a schematic illustration of a vehicle according to one embodiment of the present application;

FIG. 4 is a schematic structural view of an electrode assembly according to an embodiment of the present application;

FIG. 5 is a schematic flow chart of a method of making an electrode assembly according to one embodiment of the present application;

FIG. 6 is a schematic cross-sectional view of an electrode assembly according to one embodiment of the present application;

FIG. 7 is a schematic block diagram of an apparatus for preparing an electrode assembly according to one embodiment of the present application;

FIG. 8 is a partial schematic view of an apparatus for preparing an electrode assembly according to one embodiment of the present application;

FIG. 9 is a schematic diagram of the initial components of one embodiment of the present application;

FIG. 10 is a schematic view of a composite assembly according to one embodiment of the present application;

FIG. 11 is a schematic cross-sectional view of a composite layer according to one embodiment of the present application;

Fig. 12 is another cross-sectional schematic view of an electrode assembly according to one embodiment of the present application.

Fig. 13 is another partial schematic view of an apparatus for preparing an electrode assembly according to one 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.

For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, 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 apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description and claims of the present application and in the description of the figures above are intended to cover non-exclusive inclusions. The terms first, second and the like in the description and in the claims or in the above-described figures, are used for distinguishing between different objects and not necessarily 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 may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.

In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "attached" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

The term "and/or" in this application is merely an association relation describing an associated object, and indicates that three relations may exist, for example, a and/or B may indicate: a exists alone, A and B exist together, and B exists alone. In this application, the character "/" generally indicates that the associated object is an or relationship.

In the embodiments of the present application, the same reference numerals denote the same components, and in the interest of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, etc. dimensions of the various components in the embodiments of the present application, as well as the overall thickness, length, width, etc. dimensions of the integrated device, are illustrative only and should not be construed as limiting the present application in any way.

The term "plurality" as used herein refers to two or more (including two), and similarly, "plural sets" refers to two or more (including two), and "plural sheets" refers to 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 by the embodiment of the present application. The battery cells may be cylindrical, flat, rectangular, or otherwise shaped, as well as the embodiments herein are not limited in this regard. The battery cells are generally classified into three types according to the packaging method: the cylindrical battery cell, the square battery cell and the soft pack battery cell are not limited thereto.

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, or the like. The battery generally includes a case for enclosing one or more battery cells. The case body can prevent liquid or other foreign matters from affecting the charge or discharge of the battery cells.

The battery cell 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 relies on metal ions to move between the cathode and anode electrode sheets. The cathode plate comprises a cathode current collector and a cathode active material layer, wherein the cathode active material layer is coated on the surface of the cathode current collector, the cathode current collector without the cathode active material layer protrudes out of the cathode current collector coated with the cathode active material layer, and the cathode current collector without the cathode active material layer is used as a cathode tab. Taking a lithium ion battery as an example, the material of the cathode current collector can be aluminum, and the cathode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium or lithium manganate and the like. The anode plate comprises an anode current collector and an anode active material layer, wherein the anode active material layer is coated on the surface of the anode current collector, the anode current collector without the anode active material layer protrudes out of the anode current collector coated with the anode active material layer, and the anode current collector without the anode active material layer is used as an anode lug. 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 is passed without fusing, the number of cathode lugs is multiple and stacked together, and the number of anode lugs is multiple and stacked together. The material of the separator may be polypropylene (PP) or Polyethylene (PE). In addition, the electrode assembly may be a wound structure or a lamination structure, and the embodiment of the present application is not limited thereto.

For a laminated electrode assembly, conventional processing methods generally have many drawbacks. Fig. 1 is a schematic view illustrating a method of manufacturing a conventional laminated electrode assembly 100, and fig. 2 is a schematic cross-sectional view illustrating a conventional laminated electrode assembly 100, for example, the electrode assembly 100 shown in fig. 2 is the electrode assembly 100 manufactured by the manufacturing method shown in fig. 1; the cross-section of fig. 2 may be parallel to the end face of the electrode assembly 100 where the tab is located. As shown in fig. 1 and 2, the electrode assembly 100 includes: anode tab 101, a plurality of cathode tabs 102, a first separator 103, and a second separator 104.

Specifically, as shown in fig. 1 and 2, in processing the electrode assembly 100, the anode sheet 101 may first pass through the first cutter 110 to obtain a plurality of scores on two surfaces of the anode sheet 101 oppositely disposed perpendicular to the thickness direction, respectively, which scores facilitate the subsequent bending of the anode sheet 101. The first separator 103 and the second separator 104 are respectively disposed on two opposite surfaces of the anode pole piece 101, so that the first separator 103, the second separator 104, and the middle anode pole piece 101 are pressed together by the first press roller 120 and then thermally compounded by the heating plate 130, thereby obtaining a composite first separator 103, anode pole piece 101, and second separator 104.

Thereafter, the cathode tab assembly 1020 is cut by the second cutter 140 to obtain a plurality of cathode tabs 102, and the plurality of cathode tabs 102 are respectively disposed at the uppermost or lowermost portions of the composite first separator 103, the anode tab 101 and the second separator 104. Specifically, a plurality of cathode pole pieces 102 are disposed at intervals on the upper surface of the upper first separator 103; a plurality of cathode pole pieces 102 are also arranged on the lower surface of the second isolating film 104 below at intervals; the upper cathode pole piece 102 and the lower cathode pole piece 102 are also arranged at intervals; each cathode sheet 102 corresponds to a position between adjacent scores in the anode sheet 101. The cathode sheet 102, the first separator 103, the anode sheet 101 and the second separator 104 are jointly pressed by the second press roller 150, so that one side surface of the cathode sheet 102 is relatively fixed with the first separator 103 or the second separator 104. After further pressing by the third press roller 160, the anode sheet 101 may be bent at the score, and thus the electrode assembly 100 as illustrated in fig. 2 may be formed on the stack 170.

As shown in fig. 2, the anode tab 101 includes a plurality of laminated segments 1011 and a plurality of bent segments 1012, wherein each bent segment 1012 is configured to connect two adjacent laminated segments 1011, and the plurality of cathode tabs 102 are alternately laminated with the plurality of laminated segments 1011 along a first direction X, which is parallel to the cross-sectional direction. In addition, the electrode assembly 100 may include the first and second separator films 103 and 104 in synchronization with the arrangement of the anode electrode sheet 101 to avoid short circuits between the anode electrode sheet 101 and the plurality of cathode electrode sheets 102.

As shown in fig. 1 and 2, in conjunction with the process of the electrode assembly 100, in the electrode assembly 100, an anode tab 101 is continuous with two separator films 103 and 104, and the process can be performed simultaneously; the plurality of cathode sheets 102 are separated from each other and need to be cut first and then fed during the manufacturing process, which can present a number of problems. For example, when each cathode sheet 102 is fed after being cut, for example, a problem of corner folding easily occurs during the extrusion of the cathode sheet 102 through the second press roller 150 or the third press roller 160, thereby affecting the performance of the electrode assembly 100 obtained by processing, and even resulting in a defective rate of the electrode assembly 100; in addition, the single cathode plate 102 has small strength and thin thickness, and the dislocation phenomenon of the cathode plate 102 caused by vibration easily occurs in the processing process, 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 a method and apparatus for preparing an electrode assembly, which can solve the above-described problems. The method for preparing the electrode assembly comprises the following steps: compounding a cathode plate and two layers of isolating films to obtain a compound layer, wherein the two layers of isolating films are respectively arranged on two surfaces of the cathode plate; the method includes alternately stacking at least one composite layer and a plurality of stacked sections of an anode electrode sheet in a first direction to obtain the electrode assembly, the anode electrode sheet including the plurality of stacked sections and at least one bent section spaced apart from the plurality of stacked sections and connected to each other. Like this, compare with traditional electrode assembly 100's processing mode, the electrode assembly of this application embodiment is through setting up the composite bed that includes cathode pole piece and two-layer barrier film, namely the cathode pole piece is compound with the barrier film, and is not compound anode pole piece and barrier film, can increase the intensity of cathode pole piece, can effectively reduce the phenomenon that the angle is taken place to the cathode pole piece, also can reduce the cathode pole piece dislocation phenomenon, has improved electrode assembly's performance and qualification rate.

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

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 fuel 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; spacecraft including airplanes, rockets, space planes, spacecraft, and the like; the electric toy includes fixed or mobile electric toys, such as a game machine, an electric car toy, an electric ship toy, and an electric airplane toy; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railroad power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete shakers, and electric planers, among others. The embodiment of the application does not limit the electric equipment in particular.

For convenience of explanation, the following embodiments take electric equipment as an example of a vehicle.

For example, as shown in fig. 3, a schematic structural diagram of a vehicle 1 according to an embodiment of the present application, the vehicle 1 may be a fuel-oil vehicle, a gas-fired vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended range vehicle. The vehicle 1 may be provided with a motor 40, a controller 30 and a battery 10, the controller 30 being arranged 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 the tail of the vehicle 1. The battery 10 may be used for power supply of the vehicle 1, e.g. the battery 10 may be used as an operating power source for the vehicle 1, for electrical circuitry of the vehicle 1, e.g. for start-up, navigation and operational power requirements of the vehicle 1. In another embodiment of the present application, the battery 10 may not only serve as an operating power source for the vehicle 1, but also as a driving power source for the vehicle 1, instead of or in part instead of fuel oil or natural gas, to provide driving power for the vehicle 1.

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 battery cells in the battery 10 may be set to any number according to different power requirements. The plurality of battery cells can be connected in series, parallel or series-parallel to realize larger 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 easy installation, and each group of battery cells constitutes a battery module. The number of battery cells included in the battery modules is not limited, and the blocks may be provided according to the need, and the battery modules may be connected in series, parallel, or series-parallel.

Alternatively, the battery 10 may further include other structures, which are not described in detail herein. For example, the battery 10 may further include a bus member for making electrical connection between a plurality of battery cells, such as parallel or series-parallel connection. Specifically, the bus member may realize electrical connection between the battery cells by connecting electrode terminals of the battery cells. Further, the bus 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 conducting mechanism.

The battery cell of an embodiment of the present application may include an outer case and an inner electrode assembly. The case may be a hollow structure for accommodating the electrode assembly. The battery cell may be provided with one or more electrode assemblies according to practical applications. The electrode assembly is a component in which electrochemical reactions occur in the battery cells. The electrode assembly may be a cylinder or a rectangular parallelepiped, etc., 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. 4 shows a schematic structural view of the electrode assembly 2 according to the embodiment of the present application, and fig. 4 exemplifies two electrode assemblies 2. As shown in fig. 4, the electrode assembly 2 includes a tab 202 and a body 201 connected, wherein the body 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 portion 201 may be formed by laminating or winding a cathode electrode sheet coated with a cathode active material layer and an anode electrode sheet coated with an anode active material layer; the cathode tab 2021 may be formed by stacking portions protruding from the cathode tab and not coating the cathode active material layer, and the anode tab 2022 may be formed by stacking portions protruding from the anode tab and not coating the anode active material layer.

Alternatively, for a plurality of electrode assemblies 2 included in a battery cell, tabs 202 of the plurality of electrode assemblies 2 may be connected. As shown in fig. 4, 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 such that the plurality of electrode assemblies 2 correspondingly include one cathode tab 2021 and one anode tab 2022, 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 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 by a connecting member, and the anode electrode terminal is electrically connected to the anode tab 2022 by a connecting member.

It should be understood that for convenience of explanation, the embodiment of the present application defines three directions perpendicular to each other with respect to the electrode assembly 2 shown in fig. 4, including a first direction X, a second direction Y, and a third direction Z. Specifically, as shown in fig. 4, the tab 202 in the embodiment of the present application may be disposed on any one end face of the electrode assembly 2, for example, the pole piece 202 may be disposed on the first end face 203 of the electrode assembly 2, and a direction perpendicular to the first end face 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 in 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 assemblies 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. 4 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 method of preparing the electrode assembly 2 according to the embodiment of the present application will be described in detail with reference to the accompanying drawings. Fig. 5 shows a schematic flow chart of a method 300 of preparing an electrode assembly 2 according to an embodiment of the present application;

fig. 6 to show a possible cross-sectional schematic view of the electrode assembly 2 according to an embodiment of the present application, for example, the electrode assembly 2 shown in fig. 6 may be a possible cross-sectional view of any one of the electrode assemblies 2 shown in fig. 4, and in particular, may be a possible cross-sectional view of the main body portion 201 of any one of the electrode assemblies 2 shown in fig. 4; the cross section shown in fig. 6 is a plane perpendicular to the direction of the end face where the tab 202 of the electrode assembly 2 is located, i.e., the cross section is perpendicular to the third direction Z. In addition, the electrode assembly 2 shown in fig. 6 may be prepared by the method 300 shown in fig. 5.

As shown in fig. 5 and 6, a method 300 of preparing an electrode assembly 2 according to an embodiment of the present application includes: s310, compounding the cathode plate 221 and two layers of isolating films 222 to obtain a compound layer 22, wherein the two layers of isolating films 222 are respectively arranged on two surfaces of the cathode plate 221; s320, alternately stacking at least one of the composite layers 22 and a plurality of stacked sections 211 of the anode tab 21 along the first direction X to obtain the electrode assembly 2, the anode tab 21 including the plurality of stacked sections 211 and at least one bent section 212, the at least one bent section 212 being spaced apart from the plurality of stacked sections 211 and connected to each other.

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

It should be understood that each of the two separator films 222 of the embodiments of the present application may be used to separate the cathode electrode tab 221 and the anode electrode tab 21, and the separator film 222 may also avoid shorting the cathode electrode tab 221 and the anode electrode tab 21.

The anode sheet 21 of the electrode assembly 2 according to the embodiment of the present application is continuous and includes a plurality of lamination sections 211 and at least one bending section 212 that are disposed at intervals, that is, one bending section 212 is between every two adjacent lamination sections 211 and one lamination section 211 is between every two adjacent bending sections 212 along the extending direction of the anode sheet 21, so as to form the laminated electrode assembly 2 as shown in fig. 6. It should be appreciated that the anode sheet 21 of the electrode assembly 2 may include one or more bent sections 212 for connecting the plurality of lamination sections 211. For convenience of explanation, the present application mainly takes the anode sheet 21 including a plurality of lamination sections 211 and a plurality of bending sections 212 as an example, but the embodiment of the present application is not limited thereto.

In the present embodiment, the electrode assembly 2 includes one or more composite layers 22. 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 laminated, that is, one lamination section 211 is disposed between every two adjacent composite layers 22 along the first direction X, and one composite layer 22 is disposed between every two adjacent lamination sections. Also, for convenience of explanation, the embodiment of the present application mainly takes the electrode assembly 2 including the plurality of composite layers 22 as an example, but the embodiment of the present application 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 sheet 22, the two surfaces being surfaces of the cathode sheet 221 perpendicular to the thickness direction of the cathode sheet 221. As shown in fig. 6, the cathode sheet 221 in the embodiment of the present application has two surfaces disposed opposite to each other, and the two surfaces are perpendicular to the thickness direction of the cathode sheet 221, that is, the two surfaces are the upper surface and the lower surface of the cathode sheet 221 in fig. 6. Two separator films 222 are respectively disposed on the upper and lower surfaces of the cathode sheet 221.

Therefore, compared with the processing procedure of the conventional electrode assembly 100, the method 300 for preparing the electrode assembly 2 in the embodiment of the application combines the cathode pole piece 221 with the two layers of isolation films 222 to form the composite layer 22, so that the strength of the cathode pole piece 221 is increased, the angle folding phenomenon of the cathode pole piece 221 can be effectively reduced, the dislocation phenomenon of the cathode pole piece 221 can be reduced, and the performance and the qualification rate of the electrode assembly 2 are improved.

It should be appreciated that the method 300 of embodiments of the present application may be performed by the apparatus 400 for preparing the electrode assembly 2. Specifically, fig. 7 shows a schematic block diagram of an apparatus 400 for preparing an electrode assembly 2 according to an embodiment of the present application, the apparatus 400 including a composite device 410 and a lamination device 420 as shown in fig. 7. Wherein, the compounding device 410 may be used to perform the step S310 in the method 300, that is, the compounding device 410 is used to compound the cathode sheet 221 and two layers of isolation films 222 to obtain the composite layer 22, where the two layers of isolation films 222 are respectively disposed on two surfaces of the cathode sheet 221; lamination device 420 may be used to perform step S320 in method 300 described above, i.e., lamination device 420 is used to alternately laminate at least one composite layer 22 with a plurality of lamination segments 211 of anode electrode sheet 21 along a first direction X to obtain electrode assembly 2, anode electrode sheet 21 comprising the plurality of lamination segments 211 and at least one bending segment 212, the at least one bending segment 212 being spaced apart from the plurality of lamination segments 211 and connected to each other.

The method 300 and apparatus 400 of embodiments of the present application are described in detail below with reference to the accompanying drawings.

In the embodiment of the present application, S310 of the method 300 may specifically include: cutting the cathode pole piece assembly 2210 into a plurality of cathode pole pieces 221, arranging the plurality of cathode pole pieces 221 between two isolation film assemblies 2220 at intervals, and performing extrusion and thermal compounding treatment to obtain a compound assembly 220; the composite assembly 220 is cut to obtain at least one composite layer 22. Thus, compared with the situation that the cathode pole piece is singly fed in the traditional electrode assembly 100, the embodiment of the application stacks the cathode pole piece 221 and the two layers of isolation films 222 after processing the cathode pole piece 221 and the two layers of isolation films 222 into the composite layer 22 so as to form the electrode assembly 2, the strength of the composite layer 22 is high, the phenomenon that the angle of folding occurs to the cathode pole piece 221 can be effectively reduced, the phenomenon that the cathode pole piece 221 is misplaced can be reduced, and the performance and the qualification rate of the electrode assembly 2 are improved.

Specifically, fig. 8 shows a partial schematic view of an apparatus 400 according to an embodiment of the present application, and as shown in fig. 8, the compounding device 410 may include: a first cutter 411 for cutting the cathode electrode sheet assembly 2210 into a plurality of cathode electrode sheets 221; a first pressing roller 412 for pressing the plurality of cathode sheets 221 and the two separation film assemblies 2220 while disposing the plurality of cathode sheets 221 between the two separation film assemblies 2220 at a distance from each other and passing through the first pressing roller 412; a heating part 413 for performing a thermal compounding process on the plurality of cathode sheets 221 and the two separator assemblies 2220 passing through the first press roller 412 to obtain a composite assembly 220; a second cutter 414 for cutting the composite assembly 220 to obtain at least one composite layer 22.

It should be understood that the cathode pole piece assembly 2210 of the embodiments of the present application represents a pole piece that is not cut into a plurality of cathode pole pieces 221, i.e., the cathode pole piece assembly 2210 is a continuous cathode pole piece. The separator assembly 2220 represents a separator that is not cut into a plurality of separators 222, i.e., the separator assembly 2220 is a continuous separator. The composite assembly 220 represents a composite structure that is not cut into at least one composite layer 22, the separator in the composite assembly 220 being continuous and not cut, but the cathode electrode sheets 221 in the composite assembly 220 being a plurality of cathode electrode sheets 221 that have been cut and are spaced apart from each other.

In this embodiment, the above-mentioned disposing the plurality of cathode sheets 221 between the two separator assemblies 2220 at intervals, and performing extrusion and thermal compounding treatment to obtain the composite assembly 220 may specifically include: arranging a plurality of cathode sheets 221 at intervals between two barrier film assemblies 2220, and performing extrusion and thermal compounding treatment to obtain an initial assembly 220'; along the circumference of each cathode tab 221, two separator assemblies 2220 in the initial assembly 220' are heat-fused to obtain a composite assembly 220, the composite assembly 220 comprising a plurality of hollow structures, each hollow structure for receiving a cathode tab 221.

Specifically, fig. 9 shows a top view schematic of an initial assembly 220' of an embodiment of the present application, and fig. 10 shows a top view schematic of a composite assembly 220 of an embodiment of the present application. As shown in fig. 8 to 10, the heating member 413 of the embodiment of the present application may be used to: a plurality of cathode tabs 221 are disposed between two separator assemblies 2220 at a distance from each other, and subjected to extrusion and thermal compounding treatment to obtain an initial assembly 220'. As shown in fig. 9, in the initial assembly 220', two separator films 2220 are continuous, a plurality of cathode tabs 221 are arranged at intervals from each other, and the plurality of cathode tabs 221 are located between the two separator films 2220.

The heating member 413 is also configured to: along the circumference of each cathode tab 221, two separator film assemblies 2220 subjected to the heat recombination process are subjected to the heat fusion process to obtain a composite assembly 220, the composite assembly 220 comprising a plurality of hollow structures, each hollow structure for accommodating a cathode tab 221. Specifically, the heating part 413 may perform a heat-fusing process on the surrounding separator assembly 2220 of each cathode tab 221, wherein "surrounding" of the cathode tab 221 means at least a portion of an edge region surrounding the cathode tab 221, for example, a range of the heat-fusing process may be as shown by hatching in fig. 10, wherein a size of the area of the heat-fusing may be set according to practical applications, for example, may be greater than or equal to or less than a range of hatching as shown in fig. 10, and the embodiment of the present application is not limited thereto.

After the hot melting treatment, the cathode pole piece 221 can be limited within a certain range, and the movement of the cathode pole piece 221 can be limited, so that the dislocation of the cathode pole piece 221 in the subsequent processing is effectively avoided.

In an embodiment of the present application, as shown in fig. 8 to 10, cutting the composite assembly 220 to obtain at least one composite layer 22 may specifically include: two separator assemblies 2220 in the composite assembly 220 are cut along the spaced positions between the plurality of cathode electrode sheets 221 to obtain at least one composite layer 22. Specifically, the two separator assemblies 2220 of the composite assembly 220 may be cut by the second cutter 414 along the spaced positions between the plurality of cathode electrode sheets 221 to obtain at least one composite layer 22. For example, the second cutter 414 may cut the composite member 220 along the cutting line 4141 shown in fig. 10, so as to avoid cutting the cathode tab 221, resulting in a defect of the cathode tab 221 of a predetermined size, thereby affecting the energy density of the battery cells formed by the electrode assembly 2.

The composite layer 22 obtained by cutting the composite assembly 220 according to the embodiment of the present application will be described in detail with reference to the accompanying drawings. Fig. 11 shows a schematic cross-sectional view of a composite layer 22 according to an embodiment of the present application, for example, the composite layer 22 shown in fig. 11 may be any one of the composite layers 22 in fig. 6, and the cross-section of fig. 11 may be in the same plane as the cross-section of fig. 6. Fig. 12 shows a schematic cross-sectional view of the electrode assembly 2 of the embodiment of the present application, which is a cross-section perpendicular to the stacking direction of the electrode assembly 2, for example, perpendicular to the first direction X, and the cross-section shown in fig. 12 is perpendicular to the cross-section shown in fig. 11.

It should be understood that, as shown in fig. 11 to 12, the two-layer isolation film 222 in the embodiment of the present application includes a first isolation film 2221 and a second isolation film 2222, and correspondingly, may be respectively obtained by processing two isolation film assemblies 2220, where the dimensions and materials of the two-layer isolation film 222 may be set according to practical applications; the materials of the two separation films 222 may be the same or different, and the dimensions of the two separation films 222 may be the same or different. For example, the materials of the two separation films 222 may be set to be the same; also, the dimensions may be set to be the same to facilitate processing and improve the processing efficiency of the electrode assembly 2. Also, the same size of the two separator films 222 may mean that the two separator films 222 have the same size in any direction. For example, the thickness of the two separator films 222 in the first direction X is the same; since the two-layer release film assembly 2220 is cut at the same time when the composite assembly 220 is cut, the lengths of the two-layer release film 222 in the second direction Y are also the same; in addition, the lengths of the two separator films 222 in the third direction Z are also the same. And the different sizes of the two separator films 222 may mean: there is at least one direction in which the two layers of separator film 222 are different in size. For convenience of description, the embodiment of the present application takes the same size of the two-layer separator 222 as an example, but the embodiment of the present application is not limited thereto.

In the embodiment of the present application, as shown in fig. 9 and 10, the two-layer separator assemblies 2220 of the embodiment of the present application cover two surfaces of the plurality of cathode pole pieces 221, respectively; correspondingly, as shown in fig. 11 to 12, after the composite assembly 220 is cut, the composite layer 22 satisfies: the two layers of isolation films 222 cover the two surfaces of the cathode plate 221 respectively, so that at least one layer of isolation film 222 of the two layers of isolation films 222 is arranged between different positions of the laminated section 211 of the electrode assembly 2 obtained through processing and the cathode plate 221 to avoid short circuit. Specifically, the area of each separator 222 of the two separator 222 is greater than or equal to the area of the cathode electrode sheet 221, so that the separator 222 can cover the cathode electrode sheet 221, i.e., the area that will not expose the surface of the cathode electrode sheet 221, to avoid short-circuiting caused by overlapping the cathode electrode sheet 221 with the lamination section 211 of the anode electrode sheet 21 in the electrode assembly 2. For example, in fig. 11 and 12, the area of the two separator films 222 is larger than that of the cathode plate 221, so that the short circuit caused by overlapping of the cathode plate 221 and the lamination section 211 of the anode plate 21 can be effectively avoided.

In the embodiment of the present application, as shown in fig. 11 to 12, edges of two layers of separator films 222 are connected to form a hollow structure for accommodating the cathode tab 221 to avoid a short circuit. Specifically, due to the heat-fusion treatment of the two-layer release film 222, at least part of the edges of the two-layer release film 222 may be connected, that is, at least one side edge of the first release film 2221 may be connected with the corresponding at least one side edge of the second release film 2222. For example, taking a rectangular separator 222 as an example, intersecting three side edges of the first separator 2221 and the second separator 2222 may be connected, and a hollow structure may be formed between the two separators 222. Thus, when the cathode tab 221 is positioned in the hollow structure, the unconnected side of the first and second isolation films 2221 and 2222 may be used to expose the cathode tab 2022 connected to the cathode tab 221; and different areas of the cathode plate 221 are wrapped by at least one layer of isolating film in the two layers of isolating films 222, after the electrode assembly 2 is obtained by processing, the two surfaces of the cathode plate 221 facing the laminated section 211 and the laminated section 211 cannot be in lap short circuit, and meanwhile, the side edge of the cathode plate 221 facing the bending section 212 and the bending section 212 cannot be in lap short circuit, so that the performance of the electrode assembly 2 is further ensured.

For another example, two opposite side edges of the two isolation films 222 are connected to form a hollow structure with two open ends, and the open ends of the hollow structure are parallel to the first direction X and perpendicular to the bending section 212. Specifically, taking the rectangular separator 222 as an example and taking the hot melting range shown in fig. 10 as an example, two side edges of the first separator 2221 and corresponding two side edges of the second separator 2222 may be connected, so that a hollow structure with two open ends is formed in the middle of the two separators 222, the two open ends are opposite, and the two open ends are parallel to the cross section shown in fig. 5, or the two open ends are parallel to the first end 203 where the cathode tab 2022 is located. In this way, when the cathode plate 221 is in the hollow structure, both the unconnected sides of the first isolation film 2221 and the second isolation film 2222 can be used for exposing the cathode tab 2022 connected with the cathode plate 221, which is more convenient for processing; meanwhile, different areas of the cathode plate 221 are wrapped by at least one layer of isolating film in the two layers of isolating films 222, so that the two surfaces of the cathode plate 221 facing the laminating section 211 and the laminating section 211 cannot be in lap short circuit, and meanwhile, the side edge of the cathode plate 221 facing the bending section 212 and the bending section 212 cannot be in lap short circuit, so that the performance of the electrode assembly 2 is further ensured.

In an embodiment of the present application, for the composite layer 22 obtained by processing, the method 300 may further include: quality testing of the composite layer 22; based on the test results of the composite layer 22, the acceptable composite layer 22 is determined, and the electrode assembly 2 includes the acceptable composite layer 22. Specifically, as shown in fig. 8, the apparatus 400 of the embodiment of the present application may further include: test apparatus 430, test apparatus 430 may be configured to: performing a quality test on the composite layer 22; based on the test results of the composite layer 22, the composite layer 22 is determined to be acceptable, and the electrode assembly 2 includes the composite layer 22 that is acceptable.

The quality of the composite layer 22 can be detected by testing the composite layer 22 by the testing device 430, unqualified composite layers 22 can be filtered and eliminated in time, and qualified composite layers 22 are used for processing the electrode assembly 2, so that the qualification rate of the electrode assembly 2 is improved. For example, in the process of obtaining a plurality of cathode tabs 221 by cutting the cathode assembly 2210, burrs are easily generated at the cut portions of the cathode tabs 221, and the burrs risk piercing the separator 222. If the cathode tab 221 having burrs is not filtered in advance, it is likely to cause internal lap short circuit of the electrode assembly 2 obtained by processing, and the yield of the electrode assembly 2 is lowered. In the embodiment of the application, the cathode pole piece 221 with burrs can be filtered through the detection of the composite layer 22, so that the formation of the electrode assembly 2 by the unqualified cathode pole piece 221 is avoided, and the qualification rate of the electrode assembly 2 can be effectively improved. Similarly, the detection of the composite layer 22 may also include other types of detection, for example, whether the cathode sheet 221 is dislocated, whether the cathode sheet 221 is folded, whether the composite layer 22 has impurities or dust particles, etc., which is not limited thereto.

Optionally, quality testing of the composite layer 22 may include: a high potential (Hipot) test is performed on the composite layer 22, that is, the Hipot test is performed on the composite layer 22 by the test device 430 to determine the voltage-withstanding insulation effect of the composite layer 22.

In the embodiment of the present application, for the obtained composite layer 22, S320 of the method 300 may specifically include: a plurality of composite layers 22 are alternately and misplaced on the two surfaces of the anode pole piece 21, so that two adjacent composite layers 22 are respectively positioned on the two surfaces of the anode pole piece 21, a plurality of lamination sections 211 are areas of the anode pole piece 21 corresponding to the plurality of composite layers 22, and a bending section 212 is an area between the two adjacent lamination sections 211 of the anode pole piece 21; the bending section 212 is bent so that the plurality of composite layers 22 and the plurality of lamination sections 211 are alternately laminated in the first direction X.

Specifically, fig. 13 shows a partial schematic view of an apparatus 400 according to an embodiment of the present application, where S320 may be implemented by the lamination device 420 shown in fig. 13. Specifically, the lamination device 420 may be configured to alternately and dislocate a plurality of composite layers 22 on two surfaces of the anode sheet 21, so that two adjacent composite layers 22 are respectively located on two surfaces of the anode sheet 21. Thus, with the electrode assembly 2 obtained by processing, the plurality of lamination sections 211 are regions of the anode sheet 21 corresponding to the plurality of composite layers 22, and the bent section 212 is a region between adjacent two lamination sections 211 of the anode sheet 21. The lamination device 420 may also be used to bend each bending section 212 such that a plurality of composite layers 22 are alternately stacked with a plurality of stacked sections 211 along the first direction X.

Alternatively, as shown in fig. 13, the lamination device 420 of the embodiment of the present application may include at least one of the following: a second press roller 422, a third press roller 423 and a stacking table 424. Specifically, after the plurality of composite layers 22 are alternately and misplaced on the anode pole piece 21, the plurality of composite layers 22 and the anode pole piece 21 can be relatively fixed by extruding through the second press roller 422; in addition, the plurality of composite layers 22 and the anode sheet 21 may be further pressed by the third pressing roller 423 to obtain the electrode assembly 2 on the lamination stage 424 after the pressing. For example, the plurality of composite layers 22 and the anode sheet 21 pressed by the third press roller 423 may fall down to the stacking table 424 under the action of gravity to obtain the electrode assembly 2.

In the embodiment of the present application, as shown in fig. 12, the orthographic projection of the composite layer 22 on the lamination section 211 of the anode sheet 21 is located within the lamination section 211 to avoid lithium precipitation. 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 positioned within the lamination section 211, that is, when the composite layers 22 are disposed on both surfaces of the anode electrode sheet 21, the position of each composite layer 22 does not exceed the range of the anode electrode sheet 21, so that the composite layer 21 does not exceed the range of the lamination section 211, that is, the cathode electrode sheet 221 of the composite layer 22 can be prevented from exceeding the range of the lamination section 211 of the anode electrode sheet 21, and thus lithium precipitation can be avoided.

Optionally, in the method 300 of the embodiment of the present application, the step of alternately and dislocating the plurality of composite layers 22 on the two surfaces of the anode pole piece 21 so that two adjacent composite layers 22 are respectively located on the two surfaces of the anode pole piece 21 may include: a plurality of nicks 2121 are alternately and misplaced on the two surfaces of the anode plate 21, two adjacent nicks 2121 in the plurality of nicks 2121 are respectively positioned on the two surfaces of the anode plate 21, and the plurality of nicks 2121 are respectively positioned on the plurality of bending sections 212; a plurality of composite layers 22 are alternately and misplaced on the two surfaces of the anode pole piece 21, and the composite layers 22 are positioned between two adjacent scores 2121; correspondingly, the foregoing step of bending the bending section 212 to alternately laminate the plurality of composite layers 22 and the plurality of laminated sections 211 along the first direction X may include: the plurality of bending sections 212 are bent at the plurality of scores 2121 so that the plurality of composite layers 22 and the plurality of lamination sections 211 are alternately laminated in the first direction X.

As shown in fig. 13, the lamination device 420 may further include: the scoring member 421, for example, may be a knife or other member for forming a score 2121. Specifically, the scoring component 421 may alternatively and dislocate a plurality of scores 2121 on two surfaces of the anode sheet 21, two adjacent scores 2121 of the plurality of scores 2121 are respectively located on two surfaces of the anode sheet 21, and the plurality of scores 2121 are respectively located on the plurality of bending sections 212. Correspondingly, the lamination device 420 is provided with a plurality of composite layers 22 alternately and in a staggered manner on two surfaces of the anode sheet 21, and the composite layers 22 are positioned between the two adjacent scores 2121. In this way, since the scores 2121 are provided, the anode sheet 21 is easily bent at the plurality of scores 2121 by gravity, and the scores 2121 of different surfaces make the bending direction different. Accordingly, as shown in fig. 13 and 6, in the electrode assembly 2 formed on the lamination stage 424, the plurality of bending sections 212 are formed correspondingly to the regions where the plurality of scores 2121 are located, and the scores 2121 are located on the surface of the bending sections 212 away from the composite layer 22, and the plurality of composite layers 22 and the plurality of lamination sections 211211 are alternately laminated along the first direction X.

Optionally, the method 300 further comprises: an insulating layer 23 is provided on a surface of a first lamination section 2111 of the anode sheet 21 of the electrode assembly 2, which is remote from the composite layer 22, the first lamination section 2111 being a lamination section including a start end or a junction end of the anode sheet 21 among the plurality of lamination sections 211. Specifically, the apparatus 400 may further include: an insulating treatment member through which an insulating layer 23 is provided on a surface of the first lamination section 2111 of the anode tab 21 of the electrode assembly 2, which surface is remote from the composite layer 22.

Specifically, taking fig. 6 as an example, the first lamination section 2111 of the embodiment of the present application may be a lamination section including the start end 213 of the anode tab 21, and then one surface of the first lamination section 2111 faces the composite layer 22 and the other surface is away from the composite layer 22, and thus, an insulating layer 23 may be provided on the surface of the first lamination section 2111 away from the composite layer 22 to protect the electrode assembly 2, for example, the first lamination section 2111 may be protected. Similarly, the first lamination section 2111 may also be a lamination section including the trailing end 214 of the anode electrode sheet 21, so that one surface of the first lamination section 2111 faces the composite layer 22 and the other surface is away from the composite layer 22, and thus, an insulating layer 23 may be provided on the surface of the first lamination section 2111 away from the composite layer 22 to protect the electrode assembly 2, for example, the first lamination section 2111 may be protected.

It should be understood that the material of the insulating layer 23 in the embodiment of the present application may be set according to practical applications. For example, the material of the insulating layer 23 may be the same as that of the both side separation films 222 of the embodiment of the present application, so as to facilitate processing.

Optionally, the electrode assembly 2 according to the embodiments of the present application may further include a finishing glue, where the finishing glue may be used to form at least part of the outer surface of the electrode assembly 2, so as to serve as the electrode assembly 2, to be used for fixing the electrode assembly 2, to avoid problems such as loose collapse of the electrode assembly 2, and to increase the structural strength and stability of the electrode assembly 2. The material of the ending glue can be set according to practical application.

Thus, in the method 300 and the apparatus 400 for manufacturing the electrode assembly 2 according to the embodiments of the present application, the cathode tab 221 and the two-layer separator 222 are combined to obtain the composite layer 22, and the two-layer separator 222 are disposed on both surfaces of the cathode tab 221, respectively; the at least one composite layer 22 and the plurality of lamination sections 211 of the anode electrode sheet 21 are alternately laminated in the first direction X to obtain the electrode assembly 2, the anode electrode sheet 21 includes the plurality of lamination sections 211 and at least one bending section 212, and the at least one bending section 212 is disposed apart from the plurality of lamination sections 211 and connected to each other. Like this, compare with traditional electrode assembly 100's processing mode, electrode assembly 2 of this application embodiment sets up the composite bed 22 that includes negative pole piece 221 and two-layer barrier film 222, namely the negative pole piece 221 is compound with barrier film 222, and is not compound positive pole piece 21 with barrier film 222, can increase the intensity of negative pole piece 221, can effectively reduce the phenomenon that negative pole piece 221 takes place the dog-ear, also can reduce negative pole piece 221 dislocation phenomenon, has improved electrode assembly 2's performance and qualification rate.

While the present 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 present application. In particular, the technical features mentioned in the respective embodiments may be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions falling within the scope of the claims.

Claims

1. A method of making an electrode assembly, comprising:

compounding a cathode plate and two layers of isolating films to obtain a composite layer, wherein the two layers of isolating films are respectively arranged on two surfaces of the cathode plate;

and alternately stacking a plurality of stacked sections of at least one composite layer and an anode electrode plate along a first direction to obtain the electrode assembly, wherein the anode electrode plate comprises the stacked sections and at least one bending section, and the bending section and the stacked sections are arranged at intervals and are connected with each other.

2. The method of claim 1, wherein the compositing the cathode sheet and the two separator films to obtain a composite layer comprises:

Cutting the cathode plate assembly into a plurality of cathode plates,

arranging a plurality of cathode pole pieces between two isolating membrane assemblies at intervals, and performing extrusion and thermal compounding treatment to obtain a composite assembly;

cutting the composite assembly to obtain at least one of the composite layers.

3. The method of claim 2, wherein said trimming said composite assembly to obtain at least one of said composite layers comprises:

cutting the two separation membrane assemblies in the composite assembly along the interval position among the cathode pole pieces to obtain at least one composite layer.

4. A method according to claim 2 or 3, wherein the two-layer separator film assembly covers both surfaces of a plurality of the cathode sheets, respectively.

5. The method of claim 4, wherein said disposing a plurality of said cathode sheets in spaced relation to each other between two separator membrane modules and performing extrusion and thermal compounding processes to obtain a composite module comprises:

arranging a plurality of cathode pole pieces between two isolating membrane assemblies at intervals, and performing extrusion and thermal compounding treatment to obtain an initial assembly;

And carrying out hot melting treatment on the two isolating membrane assemblies in the initial assembly along the periphery of each cathode pole piece to obtain a composite assembly, wherein the composite assembly comprises a plurality of hollow structures, and each hollow structure is used for accommodating the cathode pole piece.

6. The method according to any one of claims 1 to 5, further comprising:

performing quality test on the composite layer;

and determining the qualified composite layer according to the test result of the composite layer, wherein the electrode assembly comprises the qualified composite layer.

7. The method of claim 6, wherein said quality testing said composite layer comprises:

and performing a Hipot test on the composite layer.

8. The method according to any one of claims 1 to 7, wherein the alternately stacking the at least one composite layer and the plurality of stacked segments of the anode electrode sheet along the first direction comprises:

a plurality of composite layers are alternately and misplaced on two surfaces of the anode pole piece, so that two adjacent composite layers are respectively positioned on the two surfaces of the anode pole piece, the plurality of lamination sections are areas of the anode pole piece corresponding to the plurality of composite layers, and the bending section is an area between the two adjacent lamination sections of the anode pole piece;

And bending the bending section so that a plurality of composite layers and a plurality of lamination sections are alternately laminated along the first direction.

9. The method of claim 8, wherein the alternately and staggering the plurality of composite layers on the two surfaces of the anode sheet so that two adjacent composite layers are respectively located on the two surfaces of the anode sheet comprises:

a plurality of nicks are alternately and misplaced on the two surfaces of the anode pole piece, two adjacent nicks in the plurality of nicks are respectively positioned on the two surfaces of the anode pole piece, and the plurality of nicks are respectively positioned on a plurality of bending sections;

a plurality of composite layers are alternately and misplaced on the two surfaces of the anode pole piece, and the composite layers are positioned between the two adjacent scores;

the bending section is bent to enable the composite layers and the laminated sections to be alternately laminated along the first direction, and the bending section comprises:

and bending the bending sections at the notches so that the composite layers and the lamination sections are alternately laminated along the first direction.

10. The method according to any one of claims 1 to 9, further comprising:

An insulating layer is arranged on the surface, far away from the composite layer, of a first lamination section of the anode pole piece of the electrode assembly, wherein the first lamination section is a lamination section comprising the initial end or the junction tail end of the anode pole piece in the lamination sections.

11. An apparatus for preparing an electrode assembly, comprising:

the composite device is used for compositing the cathode pole piece and two layers of isolating films to obtain a composite layer, and the two layers of isolating films are respectively arranged on the two surfaces of the cathode pole piece;

lamination means for alternately laminating at least one of the composite layers and a plurality of lamination sections of an anode electrode sheet in a first direction to obtain the electrode assembly, the anode electrode sheet including the plurality of lamination sections and at least one bending section, the at least one bending section being disposed at intervals from the plurality of lamination sections and connected to each other.

12. The apparatus of claim 11, wherein the compounding device comprises:

a first cutter for cutting the cathode plate assembly into a plurality of cathode plates,

the first press roll is used for extruding the cathode pole pieces and the two isolating membrane assemblies when the cathode pole pieces are arranged between the two isolating membrane assemblies at intervals and pass through the first press roll;

The heating component is used for carrying out heat compounding treatment on the plurality of cathode pole pieces passing through the first compression roller and the two isolating membrane assemblies so as to obtain a compound assembly;

and a second cutter for cutting the composite assembly to obtain at least one composite layer.

13. The apparatus of claim 12, wherein the second cutter is configured to:

14. The apparatus of claim 12 or 13, wherein the two-layer separator film assembly covers both surfaces of the plurality of cathode sheets, respectively.

15. The apparatus of claim 14, wherein the heating component is further configured to:

and carrying out hot melting treatment on the two isolating membrane assemblies subjected to the thermal compounding treatment along the periphery of each cathode pole piece so as to obtain a compound assembly, wherein the compound assembly comprises a plurality of hollow structures, and each hollow structure is used for accommodating the cathode pole piece.

16. The apparatus according to any one of claims 11 to 15, characterized in that the apparatus further comprises: a testing device for:

Performing quality test on the composite layer;

17. The apparatus of claim 16, wherein the testing device is configured to:

and performing a Hipot test on the composite layer.

18. The apparatus according to any one of claims 11 to 17, wherein the lamination device is configured to:

19. The apparatus of claim 18, wherein the lamination device comprises:

the notch component is used for alternately and misplaced arranging a plurality of notches on the two surfaces of the anode pole piece, wherein two adjacent notches in the plurality of notches are respectively positioned on the two surfaces of the anode pole piece, and the plurality of notches are respectively positioned on a plurality of bending sections;

The lamination device is used for:

a plurality of composite layers are alternately and misplaced on the two surfaces of the anode pole piece, the composite layers are positioned between the two adjacent nicks,

and bending the bending sections at the notches so that the composite layers and the lamination layers are alternately stacked along the first direction.

20. The apparatus according to any one of claims 11 to 19, characterized in that the apparatus further comprises:

and the insulation treatment component is used for arranging an insulation layer on the surface, far away from the composite layer, of a first lamination section of the anode pole piece of the electrode assembly, wherein the first lamination section is a lamination section comprising the initial end or the junction tail end of the anode pole piece in the lamination sections.