Electrode assembly and processing method thereof, battery monomer, battery and power utilization device

Abstract

The invention discloses an electrode assembly, a processing method, a battery monomer, a battery and an electric device, and belongs to the technical field of batteries. The electrode assembly comprises an active material coating part and a tab part connected to the active material coating part, the tab part comprises a first lamination part and a second lamination part which are connected, the first lamination part is formed by connecting overlapped areas of multiple layers of laminated tab pieces, and the second lamination part is formed by connecting overlapped areas of multiple layers of laminated tab pieces. And the second laminated part is formed by bending the first part of the staggered area of the laminated multiple layers of tab pieces towards the residual second part along the direction close to the first laminated part and then jointly laminating and connecting the first part and the residual second part. According to the technical scheme, by reusing the dislocation area of the multiple layers of tab pieces, the adverse effect of the dislocation area of the multiple layers of tab pieces on the subsequent working procedure is improved, meanwhile, the electric connection area of the tab part and the pole is enlarged, the overcurrent capacity is improved, the working procedure and time for adjusting the position of a cutter in real time are omitted, and the production efficiency is improved. And the processing efficiency of the electrode assembly and the material utilization rate of the tab are improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to an electrode assembly and processing method, a battery cell, a battery, and an electrical device. Background Art

[0002] In recent years, new energy vehicles have developed by leaps and bounds. In the field of electric vehicles, power batteries, as the power source of electric vehicles, play an irreplaceable and important role. Among them, power batteries include several battery cells. However, the performance and manufacturability of battery cells need to be improved. Summary of the invention

[0003] The embodiments of the present application provide an electrode assembly and a processing method, a battery cell, a battery, and an electrical device, which can improve the performance and manufacturability of the battery cell.

[0004] In a first aspect, an embodiment of the present application provides an electrode assembly, comprising: an active material coating portion and a pole ear portion, the pole ear portion being connected to the active material coating portion, and the pole ear portion comprising a first stacking portion and a second stacking portion which are connected and formed by connecting through overlapping areas of stacked multi-layer pole ear sheets, and the second stacking portion is formed by bending a first portion of an offset area of ​​the stacked multi-layer pole ear sheets in a direction close to the first stacking portion toward a remaining second portion, and then stacking and connecting together.

[0005] In the above technical solution, the misaligned area of ​​the multi-layered pole tabs is reused by stacking and connecting after bending, which improves the adverse effects of the misaligned area of ​​the multi-layered pole tabs on subsequent processes, and at the same time expands the electrical connection area between the pole tabs and the poles, improves the current capacity, and is conducive to improving the performance of the battery cell. In addition, the process and time of adjusting the position of the cutter in real time are omitted, which is conducive to improving the processing efficiency of the electrode assembly, meeting the beat requirements of the high-speed mass production line, and reducing material waste, improving the material utilization rate of the pole tabs, and thus improving the manufacturability of the battery cell.

[0006] In some embodiments, the folds of the second laminated portion are parallel to corresponding side outer edges of the tabs.

[0007] In the above technical solution, by setting the fold of the second stacking part parallel to the corresponding side outer edge of the pole ear sheet, it is beneficial to maximize the overlapping area of ​​the first part and the second part in the second stacking part, thereby increasing the available area of ​​the second stacking part, so as to increase the electrical connection area between the pole ear part and the pole, and further improve the current efficiency.

[0008] In some embodiments, the electrode ear portion is formed into a trapezoidal structure with a lower base connected to the active material coating portion.

[0009] In the above technical solution, by processing the pole ear portion into a trapezoidal structure with the lower bottom connected to the active material coating portion, it is beneficial to improve the connection reliability between the pole ear portion and the active material coating portion, and improve the conductivity reliability. In addition, when the fold of the second stacked portion is parallel to the corresponding side outer edge of the pole ear sheet, and the pole ear portion is formed into a trapezoidal structure with the lower bottom connected to the active material coating portion, the misaligned area of ​​the multi-layer pole ear sheet is also trapezoidal before bending, that is, each pole ear sheet is a trapezoidal sheet body, so that the pole ear sheet has better rigidity, is not easy to bend or warp in the winding, rolling and other processes, and the multi-layer pole ear sheets can be stacked more obediently.

[0010] In some embodiments, the edge of the first part close to the active material coating portion is the first edge, and the edge of the second part close to the active material coating portion is the second edge. There is a height difference between the first edge and the second edge, and the first edge is located on the side of the second edge away from the active material coating portion.

[0011] In the above technical solution, by setting a height difference between the first edge and the second edge, and the first edge is located on the side of the second edge away from the active material coating portion, problems such as short circuit caused by the first part being bent and inserted into the active material coating portion can be improved, thereby improving the reliability of the battery cell.

[0012] In some embodiments, the height difference between the first edge and the second edge is 0.8 mm-3 mm.

[0013] In the above technical scheme, the short circuit and other problems caused by the first part being bent and inserted into the active material coating part can be further improved, and when punching out the part of the first part close to the active material coating part, the problem of the part of the isolation membrane protruding from the pole piece body being punched out together can be improved.

[0014] In some embodiments, the maximum height difference between the third edge of the first portion away from the active material coating portion and the fourth edge of the second portion away from the active material coating portion does not exceed 2 mm.

[0015] In the above technical solution, the maximum spacing in the height direction of the trapezoid is less than or equal to 2 mm, so that the overlapping area between the first part and the second part can be larger and closer to the upper bottom of the pole ear part of the trapezoid, which is convenient for welding the pole ear part and the pole or adapter plate, and is convenient for obtaining a larger welding area, which is beneficial to improving the current efficiency.

[0016] In some embodiments, the pole ear portion extends from the first end portion of the active material coating portion, the first stack portion and the second stack portion are arranged along the length direction of the first end portion, and in the length direction of the first end portion, the length of the first portion is equal to the length of the second portion.

[0017] In the above technical solution, the first part and the second part after bending can have a larger overlapping area, so that the second stacked part can have a larger available area for welding with the pole or adapter, which is beneficial to increase the welding area to improve the current efficiency.

[0018] In some embodiments, the second laminated portion is disposed on both sides of the first laminated portion.

[0019] In the above technical solution, the available area of ​​the pole ear portion can be further increased, which is beneficial to further increase the electrical connection area between the pole ear portion and the pole, further improve the current flow efficiency, and further reduce the material waste of the pole ear portion.

[0020] In some embodiments, the thickness of the second portion decreases along a direction away from the first stacking portion, and the thickness of the first portion increases along a direction away from the first stacking portion.

[0021] In the above technical solution, the first part and the second part after stacking form a complementary thickness, that is, the thin area of ​​the first part is overlapped with the thick area of ​​the second part, and the thick area of ​​the first part is overlapped with the thin area of ​​the second part, so that the misaligned area can be stacked by bending, and the area with small thickness is bent to overlap with the area with large thickness to achieve thickness compensation, so that the misaligned area can be converted into a form of approximately equal thickness, which is beneficial to increase the welding area between the pole ear and the pole or adapter.

[0022] In some embodiments, the first portion is bent and folded on a side where the surface of the second portion changes in a step manner.

[0023] In the above technical solution, the second stacked portion composed of the first part and the second part can be formed into a form with complementary thickness inside and smooth and flat outside, so as to facilitate the pre-welding connection of the multi-layer pole ear sheets in the second stacked portion, and facilitate the subsequent use of the second stacked portion, such as facilitating the assembly of the pole ear portion and the pole, and facilitating the welding of the pole ear portion and the pole or adapter sheet.

[0024] In some embodiments, two outer-layer tab sheets in the thickness direction of the second stacked portion are arranged in the same layer as two outer-layer tab sheets in the thickness direction of the first stacked portion.

[0025] In the above technical solution, the overall outer surface of the pole ear portion can be made smoother, thereby facilitating the pre-welding connection of multiple layers of pole ear sheets in the pole ear portion, and being beneficial to the subsequent use of the pole ear portion, such as facilitating the assembly of the pole ear portion with the pole, and facilitating the welding of the pole ear portion with the pole or adapter sheet.

[0026] In some embodiments, the bent portions of the bent multi-layer tab sheets in the second stacked portion are arranged layer by layer corresponding to the unbent multi-layer tab sheets.

[0027] In the above technical solution, the thickness of the second stacked portion composed of the first part and the second part is more uniform, which is more conducive to the pre-welding connection of the multi-layer pole ear sheets in the second stacked portion, and is also conducive to the subsequent use of the second stacked portion, such as facilitating the assembly of the pole ear portion and the pole, and facilitating the welding of the pole ear portion and the pole or adapter sheet.

[0028] In some embodiments, the edges of two pole tabs arranged in the same layer in the second stacked portion are seamlessly spliced.

[0029] In the above technical solution, the air gap in the second laminated part can be reduced, which is beneficial to improving the pre-welding quality of the second laminated part and the welding yield of the pole lug part and the pole or the adapter.

[0030] In some embodiments, the first portion and the second portion of the multi-layered tab sheets are connected by welding.

[0031] In the above technical solution, the multiple layers of the pole ear sheets in the second stacked part can be simply and effectively connected together to facilitate the subsequent processing or utilization of the pole ear portion, such as facilitating the subsequent overall welding of the pole ear portion, and facilitating the assembly of the pole ear portion and the pole, and facilitating the welding of the pole ear portion and the pole or the adapter sheet.

[0032] In some embodiments, the multiple layers of pole tab sheets in the pole tab portion are connected by welding marks, a portion of the welding marks is located in the first stacking portion, and the remaining portion is located in the second stacking portion.

[0033] In the above technical solution, the pole ear sheet that connects the first stack part and the second stack part is connected by welding, which can make the structural stability of the pole ear part better and facilitate the subsequent use of the pole ear part, such as facilitating the assembly of the pole ear part and the pole, and facilitating the welding of the pole ear part and the pole or adapter sheet.

[0034] In a second aspect, an embodiment of the present application further provides a battery cell, comprising: a shell, a pole and an electrode assembly of any of the above schemes, wherein the pole is disposed in the shell, the active material coating portion is received in the shell, and the pole ear portion is electrically connected to the pole.

[0035] In the above technical solution, the electrical connection area between the pole ear and the pole can be enlarged, the current carrying capacity can be improved, and the overall processing efficiency of the battery cell can be improved.

[0036] In some embodiments, the position of the pole ear portion electrically connected to the pole is formed as a connecting portion, and the connecting portion includes a portion falling on the first laminate portion and a portion falling on the second laminate portion.

[0037] In the above technical solution, the area of ​​the connection portion can be increased, which is beneficial to increase the electrical connection area between the pole ear and the pole, so as to improve the current flow efficiency.

[0038] In some embodiments, the pole has a receiving groove, and at least a portion of the pole ear portion is received in the receiving groove.

[0039] In the above technical solution, by accommodating at least part of the pole ear portion in the accommodating groove, at least part of the pole ear portion occupies the space in the accommodating groove, thereby reducing the space occupied by the pole ear portion in the shell, saving space in the shell to accommodate a larger volume of active material coating portion, which is beneficial to improving the energy density of the battery cell, or when the energy density of the battery cell remains unchanged, it is beneficial to reduce the size of the battery cell.

[0040] In some embodiments, a accommodating cavity is formed in the shell, the accommodating groove is open in a direction away from the accommodating cavity, a connecting hole is provided on the pole, the connecting hole passes through the groove wall on one side of the accommodating groove close to the accommodating cavity, and connects the accommodating cavity and the accommodating groove, and the pole ear is passed through the connecting hole.

[0041] In the above technical solution, when injecting electrolyte into the battery cell, the electrolyte can be injected into the receiving groove and then flow toward the receiving cavity through the connecting hole, wherein the receiving groove can play the role of buffering the electrolyte to improve the problems of electrolyte splashing and overflow. Moreover, the side wall of the receiving groove can block the electrolyte splashing to a certain extent, reduce the pollution caused by the electrolyte to the outside, and facilitate rapid injection. Moreover, since there is no need to open a separate injection channel on the shell, there is no need to perform special processing on the shell, which is conducive to reducing the structural complexity and processing difficulty of the shell.

[0042] In some embodiments, the battery cell further comprises a pole cover plate, which is disposed on the pole to cover the notch of the receiving groove, and has a liquid injection hole connected to the receiving groove, and has a sealing structure for blocking the liquid injection hole.

[0043] In the above technical solution, when it is necessary to inject electrolyte into the battery cell, the sealing structure is not installed at the injection hole first, or the sealing structure is in a state of opening the injection hole, and the electrolyte can be injected into the receiving tank through the injection hole. And after the injection, the sealing structure can be installed at the injection hole, or the sealing structure can be switched to a state of closing the injection hole, so as to seal and close the injection hole to prevent the electrolyte from overflowing and prevent external foreign matter from entering the receiving cavity from the injection hole, thereby improving the reliability of the battery cell. Therefore, by processing the injection hole on the pole cover plate, the opening is relatively small and located outside, and the injection inlet can be more easily reliably sealed by the sealing structure, thereby improving the working reliability of the battery cell and realizing flexible and diversified design of the sealing structure.

[0044] In a third aspect, an embodiment of the present application further provides a battery, comprising a battery cell of any of the above-mentioned solutions.

[0045] In the above technical solution, since the performance of the battery cell according to the embodiment of the present application is improved, it is beneficial to improve the performance of the battery.

[0046] In a fourth aspect, an embodiment of the present application further provides an electrical device, comprising a battery according to any of the above solutions.

[0047] In the above technical solution, since the performance of the battery is improved, it is beneficial to improve the working power performance of the electrical device.

[0048] In a fifth aspect, an embodiment of the present application also provides a method for processing an electrode assembly, comprising the steps of: stacking and partially staggering a plurality of electrode tab sheets connected to an active material coating portion; bending a first portion of the staggered region of the plurality of electrode tab sheets toward a second portion remaining in the staggered region along a direction close to an overlapping region of the plurality of electrode tab sheets in the electrode tab portion, so that the first portion and the second portion are stacked; connecting the stacked first portion with the plurality of electrode tab sheets in the second portion to form a second stacked portion, and connecting the plurality of electrode tab sheets in the overlapping region to form a first stacked portion; the first stacked portion and the second stacked portion together form the electrode tab portion of the electrode assembly.

[0049] In the above technical solution, the dislocation area of ​​the multi-layered pole ear sheet is bent, stacked and connected to realize the reuse of the dislocation area, thereby improving the adverse effects of the dislocation area of ​​the multi-layered pole ear sheet on the subsequent assembly of the pole ear part and the subsequent welding of the pole ear part and the pole column. Moreover, compared with cutting off all the dislocation areas, it is equivalent to increasing the ultrasonic pre-welding area of ​​the pole ear part, thereby increasing the welding area of ​​the pole ear part and the pole column, which is beneficial to improve the current capacity and improve the charging and discharging efficiency of the battery cell. In addition, since there is no need to use a cutter to cut the dislocation area of ​​the pole ear part, the time for adjusting the cutter in the cutting process is saved, and the multiple pole ears of the electrode assembly do not need to be cut synchronously and the process of adjusting the cutter is introduced, which is beneficial to improve the production beat and production efficiency of the electrode assembly. In addition, since the dislocation area of ​​the multi-layered pole ear sheet is reused, material waste is reduced and the material utilization rate of the pole ear part is improved.

[0050] In some embodiments, the processing method further includes the step of: welding the multiple layers of tab sheets in the first part and the second part stacked after bending to form a second stacked part.

[0051] In the above technical solution, the multiple layers of pole ear sheets in the second stacked part can be simply and effectively connected together to facilitate the subsequent processing or utilization of the pole ear portion, such as facilitating the subsequent overall welding of the pole ear portion, facilitating the assembly of the pole ear portion with the pole, and facilitating the welding of the pole ear portion with the pole or the adapter sheet.

[0052] In some embodiments, the processing method further includes the steps of: welding the pole ear portion, welding the multiple pole ear sheets in the overlapping area to form a first stacked portion, and connecting the first stacked portion and the second stacked portion by welding.

[0053] In the above technical solution, the pole ear sheet that connects the first stack part and the second stack part is connected by welding, so that the structural stability of the pole ear part is better, so as to facilitate the subsequent use of the pole ear part, such as facilitating the assembly of the pole ear part and the pole, and facilitating the welding of the pole ear part and the pole or adapter sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0055] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0056] Figure 2 An exploded view of the structure of a battery provided in some embodiments of the present application;

[0057] Figure 3 A schematic diagram of the structure of a battery cell provided in some embodiments of the present application;

[0058] Figure 4 For along Figure 3 Sectional view along line AA;

[0059] Figure 5 for Figure 4 A partial enlarged view of part B shown;

[0060] Figure 6 A partial schematic diagram of an electrode assembly provided in some embodiments of the present application;

[0061] Figure 7 for Figure 6 A partial enlarged view of section C shown;

[0062] Figure 8 A schematic top view of an electrode assembly provided in some embodiments of the present application;

[0063] Fig. 9 for Figure 8 A partial enlarged view of the D portion shown;

[0064] Fig.10 A partial schematic diagram of an electrode assembly provided in some embodiments of the present application;

[0065] Fig.11 for Fig.10 A schematic top view of the electrode assembly shown;

[0066] Figure 12-Figure 18 for Fig.10 A schematic diagram of the processing process of the electrode assembly shown;

[0067] Fig.19 It is a schematic diagram of the welding mark between the pole ear and the pole in the related art;

[0068] Fig. 20 A schematic diagram of welding between a pole ear and a pole provided in some embodiments of the present application;

[0069] Fig.21 A partial schematic diagram of an electrode assembly provided in some embodiments of the present application;

[0070] Fig. 22 A partial cross-sectional view of an electrode assembly provided in some embodiments of the present application;

[0071] Fig.23 A schematic diagram of the cooperation between a battery cell and a busbar component provided in some embodiments of the present application;

[0072] Fig.24 A flowchart of the steps of the processing method of the electrode monomer provided in some embodiments of the present application;

[0073] Fig.25 A flow chart of the steps of a method for processing an electrode unit provided in some embodiments of the present application.

[0074] Reference numerals: vehicle 1000; first direction X; second direction Y; third direction Z; thickness direction W; battery 100; controller 200; motor 300; box 101; first box body 1011; second box body 1012; battery cell 102; current collector 103; shell 1; accommodating chamber 11; pole 2; accommodating groove 21; connecting hole 22; first weld mark M1; second weld mark M2; electrode assembly 3; active material coating portion 31; pole piece body 311; first end portion 310; positive pole piece body 3a; negative pole piece body 3b; separator 312; first surface 313; second surface 314 ; Pole ear portion 32; Pole ear sheet 320; Outer edge 3201; First laminated portion 321; Second laminated portion 322; First portion 3221; First edge 32211; Third edge 32212; Second portion 3222; Second edge 32221; Fourth edge 32222; Fold 3223; Incision 3224; Overlapping area Z1; Misaligned area Z2; First area Z21; Second area Z22; Fold line L1; Cutting path L2; Cutting starting point P; Connecting portion 4; Pole cover plate 5; Filling hole 51; Sealing structure 6; First welding head 2000; Second welding head 3000; Cutting knife 4000. DETAILED DESCRIPTION

[0075] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0076] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0077] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0078] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0079] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0080] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0081] The term "plurality" used in the present application refers to two or more (including two).

[0082] In the present application, battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries or magnesium-ion batteries, etc., and the embodiments of the present application do not limit this. Battery cells may be cylindrical, flat, rectangular or other shapes, etc., and the embodiments of the present application do not limit this. Battery cells are generally divided into three types according to the packaging method: cylindrical battery cells, square battery cells and soft-pack battery cells, and the embodiments of the present application do not limit this.

[0083] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in the present application may include a battery module or a battery pack. A battery module generally includes a plurality of battery cells. A battery pack generally includes a box for encapsulating one or more battery cells or one or more battery modules. The box can improve the effect of liquid or other foreign matter on the charging or discharging of the battery cells.

[0084] A battery cell includes a shell, an electrode assembly and an electrolyte. The shell is used to contain the electrode assembly and the electrolyte. The shell contains at least one electrode assembly, which is composed of a positive electrode sheet, a negative electrode sheet and a separator. The electrode assembly can be a wound structure or a stacked structure. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work.

[0085] The positive electrode sheet can generally include a positive electrode current collector and a positive electrode active material layer, the positive electrode active material layer is directly or indirectly coated on the positive electrode current collector, the positive electrode current collector not coated with the positive electrode active material layer protrudes from the positive electrode current collector coated with the positive electrode active material layer, and the positive electrode current collector not coated with the positive electrode active material layer serves as a positive electrode tab sheet. Taking lithium-ion batteries as an example, the material of the positive electrode current collector can be aluminum, and the material of the positive electrode active material layer can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide, etc.

[0086] The negative electrode sheet can generally include a negative electrode current collector and a negative electrode active material layer, the negative electrode active material layer is directly or indirectly coated on the negative electrode current collector, the negative electrode current collector not coated with the negative electrode active material layer protrudes from the negative electrode current collector coated with the negative electrode active material layer, and the negative electrode current collector not coated with the negative electrode active material layer serves as a negative electrode tab sheet. The material of the negative electrode current collector can be copper, and the material of the negative electrode active material layer can be carbon or silicon, etc.

[0087] In order to ensure that a large current can pass without melting, the number of positive electrode tabs is multiple and stacked together to form the positive electrode tab, and the number of negative electrode tabs is multiple and stacked together to form the negative electrode tab. A pole is provided on the shell, and the positive pole tab is electrically connected to the positive pole, and the negative pole tab is electrically connected to the negative pole. The pole tab can be welded to the pole to achieve direct electrical connection between the two, or the pole tab can also be indirectly electrically connected to the pole through an adapter, such as welding the pole tab to one end of the adapter, and welding the other end of the adapter to the pole.

[0088] In the related art, the stacked multi-layered pole tabs are connected to form the pole tabs by ultrasonic welding. However, due to the influence of processing and tolerance, the stacked multi-layered pole tabs cannot be completely overlapped, and there is a misalignment problem. During processing, the misaligned part needs to be cut off first, and then ultrasonic welding is performed. However, since the misaligned part needs to be cut off, the overall length of the pole tab becomes shorter. When the pole tab is welded to the pole column, the weld mark formed by the welding of the pole tab and the pole column is smaller in length, the flow area is smaller, and the flow efficiency is lower, which affects the charge and discharge efficiency of the battery cell. In addition, the cutting process also requires the introduction of the process and time of adjusting the cutter position, which affects the processing efficiency and beat.

[0089] To this end, an embodiment of the present application proposes an electrode assembly, in which the overlapping areas of the multi-layer pole ear sheets of the pole ear portion of the electrode assembly are connected to form a first stacked portion, and the misaligned areas of the multi-layer pole ear sheets are bent, stacked and connected to form a second stacked portion. Thus, the misaligned areas of the multi-layer pole ear sheets are reused by bending and stacking, thereby solving the adverse effects of the misaligned areas of the multi-layer pole ear sheets on subsequent processes. At the same time, the electrical connection area between the pole ear portion and the pole column is expanded, the current flow capacity is improved, and the process and time of adjusting the cutter position in real time are eliminated, which is beneficial to improving the processing efficiency of the electrode assembly, meeting the beat requirements of high-speed mass production lines, and is beneficial to reducing material waste and improving the material utilization rate of the pole ear sheets.

[0090] The embodiment of the present application provides an electric device using a battery as a power source, and the electric device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, the electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc., and the spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0091] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0092] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas 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, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0093] In some embodiments of the present application, the battery 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0094] Please refer to Figure 2 , Figure 2An exploded view of the structure of a battery 100 provided for some embodiments of the present application. The battery 100 includes a case 101 and a plurality of battery cells 102, and the battery cells 102 are accommodated in the case 101. Among them, the case 101 is used to provide an assembly space for the battery cells 102, and the case 101 can adopt a variety of structures. In some embodiments, the case 101 may include a first case body 1011 and a second case body 1012, and the first case body 1011 and the second case body 1012 cover each other, and the first case body 1011 and the second case body 1012 jointly define an assembly space for accommodating the battery cells 102. The second box body 1012 may be a hollow structure with one end open, the first box body 1011 may be a plate-like structure, and the first box body 1011 covers the open side of the second box body 1012, so that the first box body 1011 and the second box body 1012 jointly define an assembly space; the first box body 1011 and the second box body 1012 may also be hollow structures with one side open, and the open side of the first box body 1011 covers the open side of the second box body 1012. Of course, the box body 101 formed by the first box body 1011 and the second box body 1012 may be in various shapes, such as a cylinder, a cuboid, etc.

[0095] In the battery 100, multiple battery cells 102 can be connected in series, in parallel, or in a hybrid connection. A hybrid connection means that multiple battery cells 102 are connected in series and in parallel. Multiple battery cells 102 can be directly connected in series, in parallel, or in a hybrid connection, and then the whole formed by multiple battery cells 102 is accommodated in the box 101; of course, the battery 100 can also be a battery module formed by multiple battery cells 102 connected in series, in parallel, or in a hybrid connection, and then multiple battery modules are connected in series, in parallel, or in a hybrid connection to form a whole, and accommodated in the box 101. The battery 100 may also include other structures, for example, the battery 100 may also include a converging component for realizing electrical welding between multiple battery cells 102.

[0096] Each battery cell 102 may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 102 may be cylindrical, flat, or rectangular. Figure 3 In the illustrated embodiment, the length direction of the battery cell 102 is the first direction X, the width direction of the battery cell 102 is the second direction Y, and the height direction of the battery cell 102 is the third direction Z. The first direction X, the second direction Y and the third direction Z are perpendicular to each other.

[0097] In some embodiments of the present application, Figure 4 and Figure 5As shown, the battery cell 102 includes: a shell 1, a pole 2 and an electrode assembly 3, the pole 2 is arranged in the shell 1, and the electrode assembly 3 includes an active material coating portion 31 arranged in the shell 1, and a pole ear portion 32 connected to the active material coating portion 31, and the pole ear portion 32 is electrically connected to the pole 2. Exemplarily, a receiving cavity 11 is formed inside the shell 1, the active material coating portion 31 is received in the receiving cavity 11, the pole 2 is passed through the shell 1, and the pole ear portion 32 is directly welded to the pole 2 or connected through an adapter sheet, so that the pole ear portion 32 is electrically connected between the active material coating portion 31 and the pole 2. Exemplarily, in combination Fig. 22 The part of the positive electrode sheet having the positive electrode active material layer (referred to as the positive electrode sheet main body 3a), the isolation film 312, and the part of the negative electrode sheet having the negative electrode active material layer (referred to as the negative electrode sheet main body 3b) are stacked in sequence to form an active material coating part 31 by winding or laminating.

[0098] According to some embodiments of the present application, the electrode assembly 3 is as follows: Figure 6-Figure 9 As shown, the pole ear portion 32 includes a first laminated portion 321 and a second laminated portion 322 that are connected and arranged. The first laminated portion 321 is formed by connecting the overlapping area Z1 of the stacked multi-layer pole ear sheets 320, and the second laminated portion 322 is formed by bending the first portion 3221 of the misaligned area Z2 of the stacked multi-layer pole ear sheets 320 along the direction close to the first laminated portion 321 toward the remaining second portion 3222 of the misaligned area Z2, and then stacking and connecting together. That is, the multi-layer pole ear sheets 320 in the overlapping area Z1 are connected to form the first laminated portion 321, the first portion 3221 is bent to be stacked with the second portion 3222, and the misaligned area Z2 is bent and the stacked multi-layer pole ear sheets 320 are connected to form the second laminated portion 322. For example, Figure 7 The oblique grid-shaded area shown in the figure indicates the overlapping area Z1, and the regular grid-shaded area indicates the misaligned area Z2.

[0099] Among them, the pole ear part 32 is composed of a plurality of layers of pole ear sheets 320 stacked together, the portion where the projections of the plurality of layers of pole ear sheets 320 completely overlap constitutes a first stacking portion 321, and the portion where the projections of the plurality of layers of pole ear sheets 320 do not completely overlap is bent to form a second stacking portion 322. Since at least one layer of the pole ear sheet 320 includes a portion belonging to the first stacking portion 321 and a portion belonging to the second stacking portion 322, the first stacking portion 321 is connected to the second stacking portion 322.

[0100] Combination Fig.10 and Fig.11As shown, affected by factors such as manufacturing method and manufacturing tolerance, it is difficult to strictly align the multi-layer pole tab sheets 320 after stacking, and there is a phenomenon of edge misalignment. Therefore, on the projection plane perpendicular to the thickness direction W of the pole tab sheet 320, the area where the projections of the multi-layer pole tab sheets 320 completely overlap is set as the overlapping area Z1, and the area where the projections of the multi-layer pole tab sheets 320 do not completely overlap is set as the misaligned area Z2.

[0101] Combination Fig.12 and Fig.13 As shown, the misaligned area Z2 is divided into a first area Z21 and a second area Z22. For example, a fold line L1 is set in the misaligned area Z2 to divide the misaligned area Z2 into the first area Z21 and the second area Z22, that is, the first area Z21 and the second area Z22 are located on both sides of the fold line L1, wherein the tabs 320 in the first area Z21 form a first part 3221, and the tabs 320 in the second area Z22 form a second part 3222. Figure 14-16 , the tab sheet 320 in the offset region Z2 is bent along the fold line L1, so that the first portion 3221 is stacked on the second portion 3222. Fig.17 , the multi-layered tab sheets 320 stacked in the first part 3221 and the second part 3222 are connected to obtain the second stacking part 322. Fig.18 The multi-layered tab sheets 320 stacked in the overlapping area Z1 are connected to obtain a first stacking portion 321 .

[0102] Specifically, the misaligned areas of the stacked multi-layer pole tabs will have an adverse effect on the subsequent assembly of the pole tabs and the laser welding of the pole tabs and the pole posts. Therefore, in the related art, it is necessary to use a cutter to completely cut off the misaligned areas of the multi-layer pole tabs during the production process of the electrode assembly, so that only the overlapping areas without misalignment are retained in the multi-layer pole tabs. After cutting, the multi-layer pole tabs in the remaining overlapping areas are ultrasonically pre-welded to form the pole tabs, and then the pole tabs and the pole posts are laser welded. However, in the process of cutting the pole tabs, in order to ensure the cutting quality, it is necessary to adjust the position of the cutter in real time, and when the relative positions of multiple pole tabs on electrode assemblies of different specifications are different, it is also necessary to adjust the position of the cutter to achieve simultaneous cutting of multiple pole tabs on electrode assemblies of different specifications. Therefore, the processing efficiency is low, and the length of the pole tabs after cutting is shortened, and the weld mark area after welding with the pole posts is small (for example, combined with Fig.19 The welding mark formed by welding the pole ear and the pole is the first welding mark M1, and the first welding mark M1 is only located in the overlapping area), the current capacity is reduced, the charging and discharging efficiency of the battery cell is affected, and there is a problem of material waste of the pole ear sheet.

[0103] In the embodiment of the present application, the misaligned area Z2 of the multi-layered pole tab sheet 320 is bent, stacked and connected to achieve the reuse of the misaligned area Z2, thereby improving the adverse effects of the misaligned area Z2 of the multi-layered pole tab sheet 320 on the subsequent assembly of the pole tab 32 (for example, passing the pole tab 32 through the connecting hole 22 on the pole 2) and the subsequent welding of the pole tab 32 with the pole 2 or the adapter. Moreover, compared with cutting off the misaligned area Z2 completely, it is equivalent to increasing the ultrasonic pre-welding area of ​​the pole tab 32, thereby increasing the area of ​​electrical connection between the pole tab 32 and the pole 2 (for example, combining Fig. 20 , the welding mark formed by welding the pole ear portion 32 and the pole column 2 is the second welding mark M2, and the second welding mark M2 is not only located in the overlapping area Z1, but also in the dislocation area Z2), which is conducive to improving the current capacity and improving the charging and discharging efficiency of the battery cell 102. In addition, since there is no need to use a cutter to cut the dislocation area Z2 of the pole ear portion 32, the time for adjusting the cutter in the cutting process is saved, and the multiple pole ear portions 32 of the electrode assembly 3 do not need to be cut synchronously and the process of adjusting the cutter is introduced, which is conducive to speeding up the production rhythm of the electrode assembly 3 and improving the production efficiency of the electrode assembly 3. In addition, since the dislocation area Z2 of the multi-layer pole ear sheet 320 is reused, material waste is reduced and the material utilization rate of the pole ear portion 32 is improved.

[0104] In short, according to the electrode assembly 3 of the embodiment of the present application, the misaligned area Z2 of the multi-layer pole ear sheet 320 is reused by bending and then stacking and connecting, which solves the adverse effects of the misaligned area Z2 of the multi-layer pole ear sheet 320 on subsequent processes, and at the same time expands the electrical connection area between the pole ear portion 32 and the pole 2, improves the current carrying capacity, and eliminates the process and time of adjusting the cutter position in real time, which is beneficial to improving the processing efficiency of the electrode assembly 3, meeting the beat requirements of the high-speed mass production line, and is beneficial to reducing material waste and improving the material utilization rate of the pole ear sheet 320.

[0105] In some embodiments of the present application, Fig.14 The fold 3223 of the second stacked portion 322 is parallel to the corresponding side outer edge 3201 of the pole tab 320 . That is, the fold line L1 along which the misaligned region Z2 is bent is parallel to the corresponding side outer edge 3201 of the pole tab 320 .

[0106] For example, combined with Fig.10 and Fig.11 As shown, after the multiple layers of the tab sheets 320 are stacked and before the offset region Z2 is bent, the edge of the tab sheet 320 located in the offset region Z2 away from the overlapping region Z1 is the outer edge 3201 of the tab sheet 320. Figure 12-Figure 15, the misaligned area Z2 is divided into a first area Z21 and a second area Z22 by a fold line L1, and the pole tab 320 of the misaligned area Z2 is bent along the fold line L1, so that the first part 3221 and the second part 3222 are stacked, and a fold 3223 is formed at the position of the fold line L1 after bending. In the figure, the fold 3223 formed by the misaligned area Z2 on the left side after bending is parallel to the outer edge 3201 on the left side of the pole tab 320, and the fold 3223 formed by the misaligned area Z2 on the right side after bending is parallel to the outer edge 3201 on the right side of the pole tab 320.

[0107] Therefore, by setting the fold 3223 of the second stacking portion 322 parallel to the corresponding side outer edge 3201 of the pole ear sheet 320, it is beneficial to maximize the overlapping area of ​​the first part 3221 and the second part 3222 in the second stacking portion 322, thereby increasing the available area of ​​the second stacking portion 322, so as to increase the electrical connection area between the pole ear portion 32 and the pole 2, and further improve the current flow efficiency.

[0108] Of course, the present application is not limited to this. For example, in other embodiments of the present application, the fold 3223 of the second stacking portion 322 can be set to be not parallel to the corresponding side outer edge 3201 of the pole tab 320 as needed, that is, the fold line L1 along which the offset area Z2 is bent is not parallel to the corresponding side outer edge 3201 of the pole tab 320.

[0109] In some embodiments of the present application, Fig.15 As shown, the pole ear portion 32 is formed into a trapezoidal structure with the bottom connected to the active material coating portion 31. That is, the pole ear portion 32 is a trapezoid, and one side edge of the pole ear portion 32 close to the active material coating portion 31 (for example Fig.15 The lower edge of the pole ear portion 32 shown in FIG. 3 is a trapezoidal bottom, and the side edge of the pole ear portion 32 away from the active material coating portion 31 (eg Fig.15 The upper edge of the pole ear portion 32 shown in the figure is a trapezoidal upper base, and the two waists of the pole ear portion 32 are connected between the upper base and the lower base, and the pole ear portion 32 can be constructed as an isosceles trapezoid or an isosceles trapezoid.

[0110] Therefore, by processing the pole ear portion 32 into a trapezoidal structure with the bottom connected to the active material coating portion 31, it is beneficial to improve the connection reliability between the pole ear portion 32 and the active material coating portion 31, and improve the conductivity reliability. In addition, when the fold 3223 of the second stacking portion 322 is parallel to the corresponding side outer edge 3201 of the pole ear sheet 320, and the pole ear portion 32 is formed into a trapezoidal structure with the bottom connected to the active material coating portion 31, the misaligned area Z2 of the multi-layer pole ear sheet 320 is also trapezoidal before bending, that is, each pole ear sheet 320 is a trapezoidal sheet body, so that the pole ear sheet 320 has better rigidity, is not easy to bend or warp in the winding, rolling and other processes, and the multi-layer pole ear sheet 320 can be stacked more obediently.

[0111] Of course, the present application is not limited thereto. For example, in other embodiments of the present application, the pole tab 320 or the pole tab portion 32 may be processed into other shapes, such as a rectangle, a parallelogram, etc., as needed.

[0112] In some embodiments of the present application, Fig.21 As shown, the edge of the first portion 3221 close to the active material coating portion 31 is the first edge 32211, and the edge of the second portion 3222 close to the active material coating portion 31 is the second edge 32221. There is a height difference h1 between the first edge 32211 and the second edge 32221, that is, the first edge 32211 and the second edge 32221 are spaced apart in the height direction of the trapezoid, and the first edge 32211 is located on the side of the second edge 32221 away from the active material coating portion 31.

[0113] For example, when the pole ear portion 32 is located above the active material coating portion 31, the lower edge of the first portion 3221 is the first edge 32211, the lower edge of the second portion 3222 is the second edge 32221, and the first edge 32211 is higher than the second edge 32221, so that the first edge 32211 is located on the side of the second edge 32221 away from the active material coating portion 31. Thus, by setting the first edge 32211 of the first portion 3221 to be located on the side of the second edge 32221 of the second portion 3222 away from the active material coating portion 31, the short circuit and other problems caused by the first portion 3221 being bent and inserted into the active material coating portion 31 can be improved, thereby improving the reliability of the battery cell 102.

[0114] For example, combined with Figure 12-Figure 15 As shown, in order to realize bending the misaligned area Z2 along the fold line L1, the first part 3221 can be punched out at a position close to the active material coating part 31 to obtain a cut 3224, and then the first part 3221 can be bent along the fold line L1 so that the first part 3221 is stacked on the second part 3222. Since the pole tab 320 is a trapezoid, when the fold line L1 is parallel to the waistline of the trapezoid, after the first part 3221 is bent, there is a risk that the part of the first part 3221 close to the active material coating part 31 will be inserted into the active material coating part 31. Therefore, when punching, the part of the first part 3221 close to the active material coating part 31 (for example, Fig.14 The area indicated by the shaded Q in the figure is cut off, and then the first portion 3221 is bent so that the first edge 32211 of the first portion 3221 after bending is located on the side of the second edge 32221 of the second portion 3222 away from the active material coating portion 31, thereby improving problems such as short circuit caused by the first portion 3221 being inserted upside down into the active material coating portion 31 after being bent.

[0115] In some embodiments of the present application, Fig.21 and Fig. 22 As shown, the active material coating part 31 includes a stacked pole piece body 311 and a separator 312, and the lower bottom of the pole ear part 32 is connected to the pole piece body 311. Among them, the "pole piece body 311" includes: a positive pole piece body 3a and a negative pole piece body 3b, wherein the positive pole piece body 3a is the part of the positive pole piece with a positive active material layer, or the part of the positive current collector coated with a positive active material layer, and the negative pole piece body 3b is the part of the negative pole piece with a negative active material layer, or the part of the negative current collector coated with a negative active material layer. The positive pole piece body 3a and the negative pole piece body 3b are alternately arranged in sequence, and the separator 312 is sandwiched between the positive pole piece body 3a and the negative pole piece body 3b, and then the active material coating part 31 is formed by winding or laminating. The lower base of the trapezoidal positive electrode ear portion 32 is connected to the positive electrode sheet body 3 a , and the lower base of the trapezoidal negative electrode ear portion 32 is connected to the negative electrode sheet body 3 b .

[0116] Combination Fig.21 As shown, the isolation membrane 312 protrudes from the edge of the pole piece body 311 in the direction of the pole ear portion 32. For example, when the pole ear portion 32 is located above the active material coating portion 31, the upper edge of the isolation membrane 312 is higher than the upper edge of the pole piece body 311. Therefore, by arranging the isolation membrane 312 to protrude from the edge of the pole piece body 311 in the direction of the pole ear portion 32, the short circuit problem can be effectively improved and the reliability of the battery cell 102 can be improved.

[0117] In some embodiments, when the isolation membrane 312 protrudes from the edge of the pole piece body 311 toward the pole ear portion 32, the first edge 32211 is set to be located on the side of the second edge 32221 away from the active material coating portion 31, and the height difference h1 between the first edge 32211 and the second edge 32221 is set to 0.8mm-3mm, that is, the spacing in the height direction of the trapezoid is 0.8mm-3mm, for example, it can be 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.8mm, 2mm, 2.5mm, 3mm, etc., so that when punching out the part of the first part 3221 close to the active material coating portion 31, the problem of the part of the isolation membrane 312 protruding from the pole piece body 311 being punched out together can be improved.

[0118] In some embodiments of the present application, Fig.21As shown, the maximum height difference h2 between the third edge 32212 of the first part 3221 away from the active material coating part 31 and the fourth edge 32222 of the second part 3222 away from the active material coating part 31 does not exceed 2mm, that is, the maximum spacing in the height direction of the trapezoid is less than or equal to 2mm, for example, it can be 2mm, 1.9mm, 1.8mm, 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3mm, 1.2mm, 1.1mm, 0.8mm, 0.6mm, 0.4mm, etc. As a result, the overlapping area of ​​the first part 3221 and the second part 3222 can be larger and closer to the upper bottom of the trapezoidal pole ear part 32, which is convenient for welding the pole ear part 32 with the pole 2 or the adapter, and is convenient for obtaining a larger welding area, which is conducive to improving the flow efficiency.

[0119] It is worth noting that, since the pole tab 320 is a trapezoid, when the fold line L1 is parallel to the waistline of the trapezoid, after the first portion 3221 is bent, the third edge 32212 of the first portion 3221 away from the active material coating portion 31 is located on the side of the fourth edge 32222 of the second portion 3222 away from the active material coating portion 31 close to the active material coating portion 31. When the height difference between the third edge 32212 and the fourth edge 32222 is large, the overlapping area of ​​the first portion 3221 and the second portion 3222 is 1.5 m. The upper bottom of the pole ear portion 32 is far away, so that the welding mark between the pole ear portion 32 and the pole post 2 or the adapter plate needs to be close to the lower bottom direction of the pole ear portion 32, which is not convenient for welding the pole ear portion 32 and the pole post 2 or the adapter plate. Therefore, when designing the shape of the pole ear plate 320 and the position of the fold line L1 of the offset area Z2, the position of the third edge 32212 after the first part 3221 is bent can be considered, so that the maximum height difference h2 between the third edge 32212 and the upper bottom of the pole ear portion 32 does not exceed 2 mm, so as to facilitate the welding of the pole ear portion 32 and the pole post 2 or the adapter plate.

[0120] In some embodiments of the present application, Fig.14As shown, the pole ear portion 32 extends from the first end portion 310 of the active material coating portion 31, and the first laminated portion 321 and the second laminated portion 322 are arranged along the length direction of the first end portion 310. In the length direction of the first end portion 310, the length W1 of the first portion 3221 is equal to the length W2 of the second portion 3222. As a result, the first portion 3221 and the second portion 3222 can have a larger overlapping area after bending, so that the second laminated portion 322 can have a larger available area for welding with the pole 2 or the adapter, which is beneficial to increase the weld area and improve the flow efficiency. For example, when setting the fold line L1, the fold line L1 can be set at a position half the length of the dislocation area Z2, so that the dislocation area Z2 can be folded in half, so that the first portion 3221 and the second portion 3222 can have a larger overlapping area after bending, so that the second laminated portion 322 can have a larger available area for welding with the pole 2 or the adapter, which is beneficial to increase the weld area and improve the flow efficiency.

[0121] It is worth noting that the first end 310 is not limited to the end of the active material coating portion 31. For example, when the active material coating portion 31 is in a winding form, at least one of the two ends on the winding axis is the first end 310. The positive electrode ear portion 32 and the negative electrode ear portion 32 can extend from the same end, or extend from the two ends in opposite directions respectively. The present application does not impose any restrictions on this.

[0122] In some embodiments of the present application, Figure 14-16 As shown, the second laminated portion 322 is provided on both sides of the first laminated portion 321. Specifically, the pole ear portion 32 extends from the first end portion 310 of the active material coating portion 31, and the overlapping region Z1 and the misaligned region Z2 are arranged along the length direction of the first end portion 310, and in the length direction of the first end portion 310, both sides of the overlapping region Z1 have misaligned regions Z2, and the misaligned regions Z2 on both sides are not cut, but are bent respectively to form the second laminated portion 322 respectively, so that the available area of ​​the pole ear portion 32 can be further increased, which is conducive to further increasing the electrical connection area between the pole ear portion 32 and the pole 2, further improving the current efficiency, and further reducing the material waste of the pole ear portion 32.

[0123] In some embodiments of the present application, Figure 10-Figure 16As shown, the thickness of the second part 3222 tends to decrease along the direction away from the first stacked part 321, and the thickness of the first part 3221 tends to increase along the direction away from the first stacked part 321. Therefore, the first part 3221 and the second part 3222 after stacking form a complementary thickness, that is, the thin area of ​​the first part 3221 overlaps with the thick area of ​​the second part 3222, and the thick area of ​​the first part 3221 overlaps with the thin area of ​​the second part 3222, so that the misaligned area Z2 can be stacked by bending, and the area with a small thickness is bent to overlap with the area with a large thickness to achieve thickness compensation, so that the misaligned area Z2 can be converted into a form of approximately equal thickness, thereby facilitating the increase of the welding area between the pole ear part 32 and the pole 2 or the adapter.

[0124] Exemplarily, the pole ear portion 32 extends from the first end portion 310 of the active material coating portion 31, and the centers of the multilayer pole ear sheets 320 in the pole ear portion 32 are staggered in sequence along the length direction of the first end portion 310, so that the overlapping area Z1 and the misaligned area Z2 are arranged along the length direction of the first end portion 310, and in the length direction of the first end portion 310, both sides of the overlapping area Z1 have misaligned areas Z2, and before the misaligned area Z2 is bent, the multilayer pole ear sheets 320 of the misaligned area Z2 are staggered in sequence, so that the pole ear portion 32 is formed at this location in a form in which the thickness gradually decreases in the direction away from the overlapping area Z1, so that the half of the misaligned area Z2 away from the overlapping area Z1 is bent to the remaining half, so that the thinner part can overlap the thicker part, thereby realizing thickness compensation with complementary thinness and thickness.

[0125] In some embodiments of the present application, Figure 10-Figure 16 As shown, when the thickness of the second part 3222 tends to decrease in the direction away from the first stacked portion 321, and the thickness of the first part 3221 tends to increase in the direction away from the first stacked portion 321, the first part 3221 is bent and folded on the side of the second part 3222 on which the surface changes in steps, that is, the first part 3221 and the second part 3222 are stacked face to face in accordance with the side surface of the first part 3221 on which the surface changes in steps and the side surface of the second part 3222 on which the surface changes in steps, so that the second stacked portion 322 composed of the first part 3221 and the second part 3222 can be formed into a form with complementary thickness inside and smooth and flat outside, so as to facilitate the pre-welding connection of the multi-layer pole ear sheets 320 in the second stacked portion 322, and facilitate the subsequent use of the second stacked portion 322, for example, to facilitate the assembly of the pole ear portion 32 and the pole 2, and to facilitate the welding of the pole ear portion 32 and the pole 2 or the adapter.

[0126] For example, combined with Fig.10 and Fig.11As shown, when the centers of the multilayer pole tab sheets 320 in the pole tab portion 32 are sequentially staggered along the length direction of the first end portion 310, the overlapping region Z1 has offset regions Z2 on both sides of the length direction of the first end portion 310, and the surfaces of the multilayer pole tab sheets 320 in the offset regions Z2 on both sides are stepped surfaces in the opposite directions. For example, the two side surfaces in the thickness direction W of the active material coating portion 31 are respectively the first surface 313 and the second surface 314, and the side surface of the multilayer pole tab sheet 320 in the offset region Z2 on the left side of the overlapping region Z1 facing the first surface 313 is stepped, and the side surface of the multilayer pole tab sheet 320 in the offset region Z2 on the right side of the overlapping region Z1 facing the second surface 314 is stepped, combined with Figure 12-16 As shown, the first parts 3221 of the misaligned regions Z2 on both sides can be bent in opposite directions so that the first part 3221 on each side is bent and folded on the side of the surface of the second part 3222 on the same side with a step-change. For example, the first part 3221 of the misaligned region Z2 on the left side is bent in the direction of the first surface 313, and the first part 3221 of the misaligned region Z2 on the right side is bent in the direction of the second surface 314, so that the misaligned regions Z2 on both sides respectively form second stacking parts 322.

[0127] It can be understood that when the active material coating portion 31 is in a winding form, it is easier to form a form in which the centers of the multi-layered tab sheets 320 in the tab portion 32 are sequentially staggered along the length direction of the first end portion 310 .

[0128] Of course, the present application is not limited to this. For example, in other embodiments of the present application, the first part 3221 and the second part 3222 can also be bent and folded in a manner that the two parts of the longest pole ear piece 320 in the misaligned area Z2 are folded face to face. In other words, the first part 3221 and the second part 3222 are stacked away from each other in a manner that the side surface of the first part 3221 with a step-change surface and the side surface of the second part 3222 with a step-change surface, so as to achieve flexible arrangement.

[0129] In some embodiments of the present application, Figure 10-Figure 16As shown, the two outer layer tab sheets 320 in the thickness direction W of the second stacked portion 322 are arranged in the same layer as the two outer layer tab sheets 320 in the thickness direction W of the first stacked portion 321. For example, the two side surfaces in the thickness direction W of the active material coating portion 31 are respectively the first surface 313 and the second surface 314, a layer of tab sheet 320 in the second stacked portion 322 close to the first surface 313 is arranged in the same layer as a layer of tab sheet 320 in the first stacked portion 321 close to the first surface 313, and a layer of tab sheet 320 in the second stacked portion 322 close to the second surface 314 is arranged in the same layer as a layer of tab sheet 320 in the first stacked portion 321 close to the second surface 314. As a result, the overall outer surface of the pole ear portion 32 can be made smoother, thereby facilitating the pre-welding connection of the multiple layers of pole ear sheets 320 in the pole ear portion 32, and being beneficial to the subsequent use of the pole ear portion 32, such as facilitating the assembly of the pole ear portion 32 and the pole 2, and facilitating the welding of the pole ear portion 32 and the pole 2 or the adapter sheet.

[0130] Of course, the present application is not limited to this. For example, in other embodiments of the present application, the outer layer pole tab sheet 320 in the thickness direction W of the second stacking portion 322 can also be set to be stacked on the outer layer pole tab sheet 320 on the same side in the thickness direction W of the first stacking portion 321, and so on.

[0131] In some embodiments of the present application, Figure 10-Figure 16 As shown, the bent portion of the bent multi-layered pole tab sheet 320 in the second laminated portion 322 is arranged correspondingly to the unbent multi-layered pole tab sheet 320. As a result, the thickness of the second laminated portion 322 composed of the first portion 3221 and the second portion 3222 is more uniform, which is more conducive to the pre-welding connection of the multi-layered pole tab sheet 320 in the second laminated portion 322, and is conducive to the subsequent use of the second laminated portion 322, for example, facilitating the assembly of the pole tab portion 32 and the pole 2, and facilitating the welding of the pole tab portion 32 and the pole 2 or the adapter.

[0132] For example, the two side surfaces in the thickness direction W of the active material coating portion 31 are respectively the first surface 313 and the second surface 314, and the multilayer pole tab sheet 320 in the pole tab portion 32 is respectively the 1st layer to the Nth layer along the direction from the second surface 314 to the first surface 313, wherein the pole tab sheet 320 of each layer from the 1st layer to the X-1th layer in the second stacking portion 322 is not bent, and the pole tab sheet 320 of each layer from the Xth layer to the Nth layer is bent, and the pole tab sheet 320 of each layer from the 1st layer to the Nth layer is The first portion 3221 is bent onto the stacked second portion 3222, and the first layer 3222 is the same layer as the bent portion of the Nth layer. The second layer 322 is the same layer as the bent portion of the N-1th layer. The third layer 322 is the same layer as the bent portion of the N-2th layer, and so on. It can be understood that only the edge of the first layer of the tab 320 can belong to the second stack 322, or the second stack 322 only includes the edge of the first layer of the tab 320.

[0133] For example, Figure 10-Figure 16 In the example shown, N is 6, X is 4, the pole tab 320 of each layer from the 1st layer to the 3rd layer in the second stacking portion 322 is not bent, and the pole tab 320 of each layer from the 4th layer to the 6th layer is bent. In the offset area Z2 on the right side of the overlapping area Z1, a part of the pole tab 320 of each layer from the 1st layer to the 6th layer constitutes the second part 3222, and the remaining part of the pole tab 320 of each layer from the 4th layer to the 6th layer constitutes the first part 3221. The first part 3221 is bent onto the stacked second part 3222, and the unbent first layer of the second stacking portion 322 is on the same layer as the bent part of the 6th layer, the unbent second layer of the second stacking portion 322 is on the same layer as the bent part of the 5th layer, and the unbent third layer of the second stacking portion 322 is on the same layer as the bent part of the 4th layer.

[0134] In some embodiments, the edges of the two pole tabs 320 disposed in the same layer in the second stacked portion 322 are seamlessly spliced. Thus, the air gap in the second stacked portion 322 can be reduced, which is beneficial to improving the pre-welding quality of the second stacked portion 322 and the welding yield of the pole tab 32 and the pole 2 or the adapter. Figure 10-Figure 16 As shown, in the offset area Z2 to the right of the overlapping area Z1, the right edge of the first layer of the pole tab sheet 320 is seamlessly spliced ​​with the left edge of the bent portion of the sixth layer of the pole tab sheet 320, the right edge of the second layer of the pole tab sheet 320 is seamlessly spliced ​​with the left edge of the bent portion of the fifth layer of the pole tab sheet 320, and the right edge of the third layer of the pole tab sheet 320 is seamlessly spliced ​​with the left edge of the bent portion of the fourth layer of the pole tab sheet 320.

[0135] Of course, the present application is not limited to this. For example, in other embodiments of the present application, the edges of the two pole ear sheets 320 arranged in the same layer in the second stacking portion 322 can also be set to be clearance-fitted, or the bent portion of the multi-layer pole ear sheet 320 bent in the second stacking portion 322 can be set to be arranged in a non-same layer with the unbent multi-layer pole ear sheet 320 stacked layer by layer, and so on.

[0136] In some embodiments of the present application, the multi-layered tabs 320 of the first portion 3221 and the second portion 3222 are welded together. Fig.17 As shown, after the bending misalignment area Z2, a smaller ultrasonic welding head (e.g. Fig.17 The first welding head 2000 shown in the figure compacts the dislocation area Z2, so that the multi-layer pole tabs 320 in the second stacked part 322 can be simply and effectively connected together, so as to facilitate the subsequent processing or use of the pole tab 32, for example, to facilitate the subsequent overall welding of the pole tab 32, and for example, to facilitate the assembly of the pole tab 32 and the pole 2, and to facilitate the welding of the pole tab 32 and the pole 2 or the adapter. Of course, the welding of the multi-layer pole tabs 320 in the second stacked part 322 is not limited to the ultrasonic welding method, for example, it can also be replaced by other methods, such as molecular diffusion welding, resistance welding, etc.

[0137] In some embodiments of the present application, the multi-layered pole tabs 320 in the pole tab portion 32 are connected by welding, and the welded portion is located in the first laminated portion 321, and the remaining portion is located in the second laminated portion 322. Thus, the pole tabs 320 of the first laminated portion 321 and the second laminated portion 322 are connected by welding, so that the structural stability of the pole tab portion 32 is better, so as to facilitate the subsequent use of the pole tab portion 32, for example, to facilitate the assembly of the pole tab portion 32 and the pole 2, and to facilitate the welding of the pole tab portion 32 and the pole 2 or the adapter. It should be noted that the welding of the multi-layered pole tabs 320 in the pole tab portion 32 can be, but is not limited to, ultrasonic welding, and can also be replaced by other methods, such as molecular diffusion welding, resistance welding, etc.

[0138] For example, Fig.17 As shown, when a smaller ultrasonic welding head is used to compact the misaligned area Z2, it can be fed from both ends to the center, that is, gradually moved from the misaligned area Z2 to the overlapping area Z1, so that the multi-layer pole ear sheets 320 in the first stacking part 321 can also be welded together, and a weld mark is also formed at the junction of the first stacking part 321 and the second stacking part 322, so that the multi-layer pole ear sheets 320 in the pole ear part 32 can be simply and effectively connected together, so as to facilitate the subsequent use of the pole ear part 32, such as facilitating the assembly of the pole ear part 32 and the pole 2, and facilitating the welding of the pole ear part 32 and the pole 2 or the adapter.

[0139] In some embodiments of the present application, after a smaller ultrasonic horn is used to weld the pole ear portion 32 from both ends to the center, a larger ultrasonic horn (eg Fig.18 The second welding head 3000 shown in FIG. 1 integrally welds the pole ear portion 32 (combined with Fig.18 ), thereby improving the welding compaction degree of the pole ear portion 32, so as to improve the welding quality between the pole ear portion 32 and the pole 2 or the adapter.

[0140] Alternatively, in some other embodiments of the present application, when a smaller ultrasonic horn is used to pre-weld the second laminated portion 322 , instead of feeding from both ends to the center, a larger ultrasonic horn may be used to integrally weld the pole ear portion 32 .

[0141] Alternatively, in some other embodiments of the present application, it is possible to omit the use of a smaller ultrasonic horn for pre-welding the second laminated portion 322 , and directly use a larger ultrasonic horn for integrally welding the pole ear portion 32 , and so on.

[0142] According to some embodiments of the present application, Figure 3-Figure 5 As shown, a battery cell 102 is also provided, comprising: a housing 1, a pole 2 and an electrode assembly 3 of any of the above schemes, the pole 2 is arranged in the housing 1, the active material coating portion 31 is received in the housing 1, and the pole ear portion 32 is electrically connected to the pole 2. For example, the pole ear portion 32 can be welded to the pole 2 to achieve direct electrical connection between the two, or the pole ear portion 32 can also be indirectly electrically connected to the pole 2 through an adapter, such as welding the pole ear portion 32 to one end of the adapter, and welding the other end of the adapter to the pole 2.

[0143] Exemplarily, the pole ear portion 32 can be laser welded to the pole 2 to achieve direct electrical connection between the pole ear portion 32 and the pole 2. However, it should be noted that the welding of the pole ear portion 32 and the pole 2 is not limited to laser welding, and can also be replaced by other methods, such as arc welding, plasma welding, gas welding, electron beam welding, etc.

[0144] According to the battery cell 102 of the embodiment of the present application, by adopting the electrode assembly 3 of any of the above-mentioned solutions, the electrical connection area between the pole ear portion 32 and the pole 2 can be expanded, the current flow capacity can be improved, and the overall processing efficiency of the battery cell 102 can be improved.

[0145] According to some embodiments of the present application, Figure 5 As shown, the position of the pole ear portion 32 electrically connected to the pole 2 is formed as a connecting portion 4, combined with Fig. 20The connection portion 4 includes a portion falling on the first laminate portion 321 and a portion falling on the second laminate portion 322. For example, when the pole ear portion 32 is directly welded to the pole 2, the weld mark formed constitutes the connection portion 4, a portion of the connection portion 4 falls on the first laminate portion 321, and the rest falls on the second laminate portion 322, thereby increasing the area of ​​the connection portion 4, which is beneficial to increasing the electrical connection area between the pole ear portion 32 and the pole 2, so as to improve the current efficiency.

[0146] For another example, when the pole ear portion 32 is welded to the adapter plate, the weld mark formed constitutes the connecting portion 4, a portion of the connecting portion 4 falls on the first stacking portion 321, and the rest falls on the second stacking portion 322, thereby increasing the area of ​​the connecting portion 4, which is beneficial to increasing the electrical connection area between the pole ear portion 32 and the pole 2, thereby improving the current flow efficiency.

[0147] According to some embodiments of the present application, Figure 5 As shown, the pole 2 has a receiving groove 21, and at least part of the pole ear portion 32 is received in the receiving groove 21. Therefore, by receiving at least part of the pole ear portion 32 in the receiving groove 21, at least part of the pole ear portion 32 occupies the space in the receiving groove 21, thereby reducing the space occupied by the pole ear portion 32 in the housing 1, saving space in the housing 1 to accommodate a larger volume of the active material coating portion 31, thereby facilitating the improvement of the energy density of the battery cell 102, or facilitating the reduction of the size of the battery cell 102 when the energy density of the battery cell 102 remains unchanged.

[0148] In some embodiments of the present application, Figure 5 As shown, a housing 1 is formed with a housing cavity 11, and the housing groove 21 is open in a direction away from the housing cavity 11. A connecting hole 22 is provided on the pole 2, and the connecting hole 22 penetrates the groove wall of the housing groove 21 on one side close to the housing cavity 11, and connects the housing cavity 11 with the housing groove 21, and the pole ear portion 32 is penetrated by the connecting hole 22. Thus, when the electrolyte is injected into the battery cell 102, the electrolyte can be injected into the housing groove 21, and then flows toward the housing cavity 11 through the connecting hole 22, wherein the housing groove 21 can play the role of buffering the electrolyte to improve the problems of electrolyte splashing and overflow. Moreover, the side wall of the housing groove 21 (i.e., the groove wall extending from the notch of the housing groove 21 toward the housing cavity 11) can block the electrolyte from splashing to a certain extent, reduce the pollution caused by the electrolyte to the outside, and facilitate rapid injection. Moreover, since there is no need to separately open an injection channel on the housing 1, there is no need to perform special processing on the housing 1, which is conducive to reducing the structural complexity and processing difficulty of the housing 1.

[0149] It is worth noting that there may be one or more communicating holes 22, and the pole ear portion 32 may be provided through at least one of the communicating holes 22. Exemplarily, at least one communicating hole 22 can pass electrolyte, for example, at least one communicating hole 22 is vacant (i.e., the pole ear portion 32 is not provided), so that electrolyte can pass through without being hindered by the pole ear portion 32, and for another example, at least one communicating hole 22 can still pass electrolyte after the pole ear portion 32 is provided.

[0150] In some embodiments, Figure 5 As shown, the pole ear portion 32 is welded to the pole 2 to form an electrical connection, thereby realizing the electrode output of the electrode assembly 3 from the pole 2. Exemplarily, as shown in the figure, when the receiving slot 21 is open in a direction away from the receiving cavity 11, the pole ear portion 32 is welded to the side slot wall of the receiving slot 21 close to the receiving cavity 11, thereby improving the compactness of the fit and facilitating the welding operation of the two. Of course, the present application is not limited to this. In other embodiments, the pole ear portion 32 can also be set to be welded to the pole cover plate 5 described later to form an electrical connection, which is not limited here.

[0151] In some embodiments of the present application, Figure 5 As shown, the battery cell 102 also includes a pole cover plate 5, which is covered on the pole 2 to cover the notch of the receiving groove 21. The pole cover plate 5 is formed with a liquid injection hole 51 that can be connected to the receiving groove 21. The battery cell 102 also includes a sealing structure 6 for blocking the liquid injection hole 51. In this way, when it is necessary to inject electrolyte into the battery cell 102, the sealing structure 6 is not installed at the liquid injection hole 51 first, or the sealing structure 6 is in a state of opening the liquid injection hole 51, and the electrolyte can be injected into the receiving groove 21 through the liquid injection hole 51. And after the injection, the sealing structure 6 can be installed at the liquid injection hole 51, or the sealing structure 6 can be switched to a state of closing the liquid injection hole 51, so as to seal and close the liquid injection hole 51 to prevent the electrolyte from overflowing and prevent external foreign matter from entering the receiving cavity 11 from the liquid injection hole 51, thereby improving the reliability of the battery cell 102. Therefore, by processing the injection hole 51 on the pole cover 5, the opening is relatively small and located outside, and the injection inlet can be reliably sealed more easily through the sealing structure 6, thereby improving the working reliability of the battery cell 102 and realizing flexible and diversified design of the sealing structure 6.

[0152] In some embodiments, Figure 5As shown, the pole cover plate 5 does not have a portion that stops at the outside of the sealing structure 6 (i.e., the side away from the accommodating cavity 11), so that the sealing structure 6 is suitable for being installed to the pole cover plate 5 from the outside of the pole cover plate 5 (i.e., the side away from the accommodating cavity 11). In this way, by setting the sealing structure 6 to be installed to the pole cover plate 5 from the outside of the pole cover plate 5 to seal the injection hole 51, the sealing structure 6 is installed after the injection, which can ensure the sealing of the injection hole 51, and the installation position is close to the outside, which is convenient for the rapid assembly of the sealing structure 6. Moreover, the installation of the sealing structure 6 will not have an adverse effect on the connection between the pole 2 and the pole cover plate 5, ensuring the reliability of the connection between the pole cover plate 5 and the pole 2.

[0153] The sealing structure 6 can be in a detachable form or in a non-detachable fixed form. For example, when the sealing structure 6 is in a detachable form, it is convenient for maintaining the injection hole 51. For example, when the electrolyte needs to be replenished, the sealing structure 6 can be removed, the injection hole 51 can be opened, and the electrolyte can be replenished and injected into the accommodating chamber 11 through the injection hole 51. Then, the sealing structure 6 can be reinstalled. For example, the sealing structure 6 can be detachably connected to the pole cover plate 5 by means of threads or screws, so as to facilitate disassembly and assembly.

[0154] Exemplarily, when the sealing structure 6 is in a non-detachable fixed form, the sealing structure 6 can be fixed to the pole cover plate 5 by welding, riveting, etc., so as to improve the sealing reliability of the sealing structure 6 to the injection hole 51. For example, the injection hole 51 can be in a multi-segment form, and the sealing structure 6 can include a first seal that is interference-fitted with the injection hole 51, and a second seal that covers the outside of the first seal and is welded to the pole cover plate 5. Alternatively, in some embodiments, the first seal can be eliminated and only the second seal can be retained. Alternatively, in some embodiments, the second seal can be set to be detachably connected to the pole cover plate 5 by means of a screw buckle to limit the first seal to a position that is interference-fitted with the injection hole 51.

[0155] In some embodiments of the present application, Figure 5 As shown, at least part of the sealing structure 6 is embedded in the injection hole 51. That is, the sealing structure 6 can be fully embedded in the injection hole 51, or only part of the sealing structure 6 can be embedded in the injection hole 51. Thus, on the one hand, the space in the injection hole 51 can be fully utilized to improve the sealing reliability of the sealing structure 6 to the injection hole 51, and on the other hand, the height of the sealing structure 6 protruding from the injection hole 51 can be reduced, and the space occupied by the sealing structure 6 outside the pole cover 5 can be reduced, which is conducive to reducing the interference effect on the confluence component 103, increasing the connection area between the confluence component 103 and the pole cover 5, and improving the flow efficiency.

[0156] It is worth noting that the setting position of the pole 2 on the shell 1 is not limited. For example, the shell 1 may include a shell body and a cover plate. The shell body defines a space with one side open. The cover plate is arranged on the open side of the shell body to form a accommodating cavity 11 between the shell body and the cover plate. At this time, the surface of the shell body on one side opposite to the cover plate is the first shell wall, and the wall surface of the shell body connected between the first shell wall and the cover plate is the second shell wall. At this time, the pole 2 can be arranged on the first shell wall, on the second shell wall, or on the cover plate.

[0157] In addition, it should be noted that the positive pole 2 and the negative pole 2 can be located on the same side surface of the shell 1, or can be located on different side surfaces of the shell 1 respectively. For example, the positive pole 2 and the negative pole 2 can be arranged on the cover plate at the same time, or the positive pole 2 and the negative pole 2 can be arranged on the first shell wall at the same time, or one of the positive pole 2 and the negative pole 2 is arranged on the cover plate, and the other is arranged on the first shell wall, and so on.

[0158] According to the embodiments of the present application, Figure 2 As shown, a battery 100 is also provided, including a battery cell 102 of any of the above solutions. It is worth noting that the battery 100 according to the embodiment of the present application may include a box body 101, or may not include a box body 101. Therefore, since the performance of the battery cell 102 according to the embodiment of the present application is improved, it is beneficial to improve the performance of the battery 100.

[0159] For example, Fig.23 As shown, the battery 100 may further include a busbar 103, and there are multiple battery cells 102, and at least two of them are electrically connected through the busbar 103. In this way, multiple battery cells 102 can be connected in series and / or in parallel. For example, when multiple battery cells 102 are connected in series, the pole cover plate 5 of the anode of one battery cell 102 is connected to the pole cover plate 5 of the cathode of the next battery cell 102 through a busbar 103, and at the same time, the pole cover plate 5 of the cathode of the battery cell 102 is connected to the pole cover plate 5 of the anode of the previous battery cell 102 through another busbar 103.

[0160] According to an embodiment of the present application, there is also provided an electric device, comprising a battery 100 according to any of the above solutions, the battery 100 is used to provide electric energy to the electric device. The electric device may be any of the above-mentioned devices or systems using the battery 100. Since the performance of the battery 100 is improved, it is beneficial to improve the working power performance of the electric device.

[0161] In some embodiments of the present application, a processing method of the electrode assembly 3 is also proposed, combining Fig.24The processing method includes step S1, step S2 and step S3, wherein step S1 is: stacking and partially dislocating the multi-layered pole tab sheets 320 connected to the active material coating portion 31; step S2 is: bending the first portion 3221 of the dislocated region Z2 of the multi-layered pole tab sheets 320 toward the remaining second portion 3222 of the dislocated region Z2 along the direction close to the overlapping region Z1 of the multi-layered pole tab sheets 320 in the pole tab portion 32, so that the first portion 3221 and the second portion 3222 are stacked; step S3 is: connecting the stacked first portion 3221 with the multi-layered pole tab sheets 320 in the second portion 3222 to form the second stacked portion 322, and connecting the multi-layered pole tab sheets 320 in the overlapping region Z1 to form the first stacked portion 321; the first stacked portion 321 and the second stacked portion 322 together form the pole tab portion 32 of the electrode assembly 3.

[0162] The pole ear portion 32 is composed of a plurality of layers of pole ear sheets 320 stacked together. The portion where the projections of the plurality of layers of pole ear sheets 320 completely overlap constitutes a first stack portion 321, and the portion where the projections of the plurality of layers of pole ear sheets 320 do not completely overlap is bent to form a second stack portion 322. Since at least one layer of the pole ear sheet 320 includes a portion belonging to the first stack portion 321 and a portion belonging to the second stack portion 322, the first stack portion 321 is connected to the second stack portion 322.

[0163] Combination Fig.10 and Fig.11 As shown, affected by factors such as manufacturing method and manufacturing tolerance, it is difficult to strictly align the multi-layer pole tab sheets 320 after stacking, and there is a phenomenon of edge misalignment. Therefore, on the projection plane perpendicular to the thickness direction W of the pole tab sheet 320, the area where the projections of the multi-layer pole tab sheets 320 completely overlap is set as the overlapping area Z1, and the area where the projections of the multi-layer pole tab sheets 320 do not completely overlap is set as the misaligned area Z2.

[0164] Combination Fig.12 and Fig.13 As shown, the misaligned area Z2 is divided into a first area Z21 and a second area Z22. The tabs 320 in the first area Z21 form a first part 3221, and the tabs 320 in the second area Z22 form a second part 3222. Figure 14-16 , bend the tab 320 in the misaligned area Z2 so that the first portion 3221 is stacked on the second portion 3222. Fig.17 , the multi-layered tab sheets 320 stacked in the first part 3221 and the second part 3222 are connected to obtain the second stacking part 322. Fig.18 The multi-layered tab sheets 320 stacked in the overlapping area Z1 are connected to obtain a first stacking portion 321 .

[0165] By bending, stacking and connecting the dislocation area Z2 of the multi-layered pole tab sheet 320, the dislocation area Z2 is reused to improve the adverse effects of the dislocation area Z2 of the multi-layered pole tab sheet 320 on the subsequent assembly of the pole tab portion 32 and the subsequent welding of the pole tab portion 32 and the pole column 2. Moreover, compared with cutting off the dislocation area Z2 completely, it is equivalent to increasing the ultrasonic pre-welding area of ​​the pole tab portion 32, thereby increasing the welding area of ​​the pole tab portion 32 and the pole column 2, which is beneficial to improving the current capacity and the charging and discharging efficiency of the battery cell 102. In addition, since there is no need to use a cutter to cut the dislocation area Z2 of the pole tab portion 32, the time for adjusting the cutter in the cutting process is saved, and the multiple pole tab portions 32 of the electrode assembly 3 do not need to be cut synchronously and the process of adjusting the cutter is introduced, which is beneficial to improving the production beat and production efficiency of the electrode assembly 3. In addition, since the offset region Z2 of the multi-layer pole tab sheet 320 is reused, material waste is reduced and the material utilization rate of the pole tab portion 32 is improved.

[0166] In some embodiments of the present application, Fig.25 As shown, the processing method of the electrode assembly 3 further includes step S31: welding the multi-layered electrode tabs 320 in the first part 3221 and the second part 3222 that are stacked after bending to form a second stacked part 322. Fig.17 As shown, after bending the misaligned area Z2, a smaller ultrasonic welding head can be used to compact the misaligned area Z2, so that the multi-layered pole tabs 320 in the second stacked part 322 can be simply and effectively connected together, so as to facilitate the subsequent processing or use of the pole tab 32, such as facilitating the subsequent overall welding of the pole tab 32, and facilitating the assembly of the pole tab 32 and the pole 2, and facilitating the welding of the pole tab 32 and the pole 2 or the adapter. Of course, the welding of the multi-layered pole tabs 320 in the second stacked part 322 is not limited to the ultrasonic welding method, for example, it can also be replaced by other methods, such as molecular diffusion welding, resistance welding, etc.

[0167] In some embodiments of the present application, Fig.25 As shown, the processing method of the electrode assembly 3 further includes step S32: welding the pole ear portion 32, so that the multi-layer pole ear sheet 320 in the overlapping area Z1 is welded to form a first laminated portion 321, and the first laminated portion 321 is connected to the second laminated portion 322 by welding. Thus, the pole ear sheet 320 of the first laminated portion 321 and the second laminated portion 322 are connected by welding, so that the structural stability of the pole ear portion 32 is better, so as to facilitate the subsequent use of the pole ear portion 32, for example, to facilitate the assembly of the pole ear portion 32 and the pole 2, and to facilitate the welding of the pole ear portion 32 and the pole 2 or the adapter.

[0168] For example, Fig.17As shown, when a smaller ultrasonic welding head is used to compact the dislocation area Z2, it can be fed from both ends to the center, that is, gradually moved from the dislocation area Z2 to the overlapping area Z1, so that the multi-layered pole tabs 320 in the first stacking part 321 can also be welded together, and a weld mark is also formed at the junction of the first stacking part 321 and the second stacking part 322, so that the multi-layered pole tabs 320 in the pole tab part 32 can be simply and effectively connected together, so as to facilitate the subsequent use of the pole tab part 32, such as facilitating the assembly of the pole tab part 32 and the pole 2, and facilitating the welding of the pole tab part 32 and the pole 2 or the adapter. Of course, the welding of the multi-layered pole tabs 320 in the pole tab part 32 is not limited to the ultrasonic welding method, for example, it can also be replaced by other methods, such as molecular diffusion welding, resistance welding, etc.

[0169] For example, after a smaller ultrasonic horn is used to weld the pole ear portion 32 from both ends to the center, a larger ultrasonic horn may be further used to weld the pole ear portion 32 as a whole (combined with Fig.18 ), that is, a larger ultrasonic welding head covers the first laminate part 321 and the second laminate part 322, so that the multi-layer pole ear sheets 320 in the first laminate part 321 can be more reliably welded together, and the weld mark at the junction of the first laminate part 321 and the second laminate part 322 is also more reliable, thereby improving the welding compaction degree of the pole ear part 32, so as to improve the welding quality between the pole ear part 32 and the pole 2 or the adapter sheet.

[0170] Alternatively, illustratively, a smaller ultrasonic horn may be used to pre-weld only the second stack portion 322, and then a larger ultrasonic horn may be used to weld the pole ear portion 32 as a whole, that is, the larger ultrasonic horn covers the first stack portion 321 and the second stack portion 322, so that the multi-layer pole ear sheets 320 in the overlapping area Z1 are welded to form the first stack portion 321, and the multi-layer pole ear sheets 320 in the first stack portion 321 are connected to the multi-layer pole ear sheets 320 in the second stack portion 322 by welding marks.

[0171] Alternatively, in other embodiments of the present application, the step of using a smaller ultrasonic horn to pre-weld the second stack portion 322 can be omitted, and a larger ultrasonic horn can be directly used to weld the pole ear portion 32 as a whole, so that the larger ultrasonic horn covers the first stack portion 321 and the second stack portion 322, so that the multi-layer pole ear sheets 320 in the stacked first part 3221 and the second part 3222 are welded to form the second stack portion 322, the multi-layer pole ear sheets 320 in the overlapping area Z1 are welded to form the first stack portion 321, and the multi-layer pole ear sheets 320 in the first stack portion 321 are connected to the multi-layer pole ear sheets 320 in the second stack portion 322 by welding marks, etc.

[0172] Next, a method for processing the electrode assembly 3 according to a specific embodiment of the present application is described.

[0173] like Fig.10 and Fig.11 As shown, the positive electrode sheet, the separator 312, and the negative electrode sheet are sequentially stacked and wound to obtain an active material coating portion 31 and a pole ear portion 32 extending from a first end portion 310 of the active material coating portion 31. The pole ear portion 32 includes a stacked plurality of pole ear sheets 320. A CCD visual inspection system (CCD is an abbreviation for charge coupled device) is used to identify the overlapping area Z1 and the misaligned area Z2 of the plurality of pole ear sheets 320 in the pole ear portion 32.

[0174] Combination Fig.12 and Fig.13 , determine the cutting starting point P and cutting path L2 of the pole ear portion 32, and the cutting path L2 is kept at a distance of about 1 mm from the lower edge of the pole ear sheet 320 (i.e., the edge of one side close to the active material coating portion 31) (e.g. Fig.12 In the length direction of the first end portion 310, the length of the cutting path L2 is half the length of the offset region Z2 (e.g. Fig.13 The cutting blade 4000 is fed according to the determined cutting path L2, and cuts the root of the offset region Z2 of the multi-layered tab sheet 320 to obtain the cut 3224. The fold line L1 is determined, and the fold line L1 is set to be parallel to the outer edge 3201 of the tab sheet 320, and the lower end of the fold line L1 (i.e., the end close to the active material coating portion 31) intersects with the end point of the cut 3224.

[0175] Combination Fig.14 and Fig.15 The offset region Z2 is located on both sides of the fold line L1, and the first region Z21 and the second region Z22 are respectively located. The pole tab sheet 320 of the first region Z21 is turned over along the fold line L1, so that the pole tab sheet 320 of the first region Z21 is stacked with the pole tab sheet 320 of the second region Z22, that is, the bent portion of the offset region Z2 overlaps with the unbent portion. Fig.16 The thickness of the second laminated portion 322 formed after stacking is uniform. Fig.13 and Fig.14, when the pole tab 320 is a trapezoid, the first area Z21 and the second area Z22 are both parallelograms, and the first area Z21 cannot be completely overlapped with the second area Z22 after being bent, and the upper end of the first area Z21 is lower than the upper end of the second area Z22, that is, the upper end is misaligned, and the lower end of the first area Z21 is lower than the lower end of the second area Z22, that is, the lower end is misaligned. In order to avoid excessive upper end misalignment, which affects the subsequent welding of the pole tab 32 and the pole 2, the height difference h between the upper end of the first area Z21 and the upper end of the second area Z22 can be set to not more than 2mm, and in order to avoid excessive lower end misalignment, which causes the bent pole tab 320 to be inserted into the active material coating part 31, the portion of the pole tab 320 located at the lower end of the first area Z21 and lower than the lower end of the second area Z22 (for example Fig.14 The area of ​​shadow Q shown in ) is cut out.

[0176] Combination Fig.17 and Fig.18 After the offset region Z2 is bent, the first smaller welding head 2000 is first used to feed from both sides to the center and move to the overlapping region Z1 to compact and weld the multi-layered tab sheets 320 stacked after the offset region Z2 is bent. Then, the second larger welding head 3000 is used to compact and weld the junction between the first stacking part 321 and the second stacking part 322, as well as the multi-layered tab sheets 320 stacked in the first stacking part 321. Figure 5 and Fig. 20 The ultrasonically welded pole ear 32 and pole 2 are welded together by laser welding, and the weld marks formed are as follows: Fig. 20 The connection portion 4 marked therein includes not only the portion falling on the first stack portion 321 , but also the portion falling on the second stack portion 322 , thereby significantly increasing the laser welding area between the pole ear portion 32 and the pole 2 , which is beneficial to improving the current flow efficiency and further improving the performance of the battery cell 102 .

[0177] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0178] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An electrode assembly, characterized in that: include: an active material coating portion; and The pole ear portion is connected to the active material coating portion, and includes a first stacking portion and a second stacking portion that are connected and formed, wherein the first stacking portion is formed by connecting the overlapping areas of the stacked multi-layer pole ear sheets, and the second stacking portion is formed by bending the first part of the offset area of ​​the stacked multi-layer pole ear sheets along the direction close to the first stacking portion toward the remaining second part, and then stacked and connected together.

2. The electrode assembly according to claim 1, characterized in that: The folds of the second laminated portion are parallel to corresponding side outer edges of the tab sheets.

3. The electrode assembly according to claim 1 or 2, characterized in that: The pole ear portion is formed into a trapezoidal structure with a lower bottom connected to the active material coating portion.

4. The electrode assembly according to claim 3, characterized in that: The edge of the first part close to the active material coating part is the first edge, and the edge of the second part close to the active material coating part is the second edge. There is a height difference between the first edge and the second edge, and the first edge is located on the side of the second edge away from the active material coating part.

5. The electrode assembly according to claim 4, characterized in that: The height difference between the first edge and the second edge is 0.8 mm-3 mm.

6. The electrode assembly according to any one of claims 3 to 5, characterized in that: The maximum height difference between a third edge of the first portion away from the active material coating portion and a fourth edge of the second portion away from the active material coating portion does not exceed 2 mm.

7. The electrode assembly according to any one of claims 1 to 6, characterized in that: The pole ear portion extends from the first end portion of the active material coating portion, the first stacking portion and the second stacking portion are arranged along the length direction of the first end portion, and in the length direction of the first end portion, the length of the first portion is equal to the length of the second portion.

8. The electrode assembly according to any one of claims 1 to 7, characterized in that: The second stacking parts are disposed on both sides of the first stacking part.

9. The electrode assembly according to any one of claims 1 to 8, characterized in that: The thickness of the second portion decreases along a direction away from the first stacked portion, and the thickness of the first portion increases along a direction away from the first stacked portion.

10. The electrode assembly according to claim 9, characterized in that: The first portion is bent and arranged on a side where the surface of the second portion changes in a step manner.

11. The electrode assembly according to any one of claims 1 to 10, characterized in that: The two outer layer tab sheets of the second stacked portion in the thickness direction are respectively arranged in the same layer as the two outer layer tab sheets of the first stacked portion in the thickness direction.

12. The electrode assembly according to any one of claims 1 to 11, characterized in that: The bent portions of the bent multi-layer electrode tab sheets in the second stacked portion are arranged layer by layer corresponding to the unbent multi-layer electrode tab sheets.

13. The electrode assembly according to claim 12, characterized in that: The edges of the two pole tabs arranged in the same layer in the second stacked portion are seamlessly spliced.

14. The electrode assembly according to any one of claims 1 to 13, characterized in that: The first part and the second part of the multiple layers of the pole tab sheets are connected by welding.

15. The electrode assembly according to any one of claims 1 to 14, characterized in that: The multiple layers of the pole tab sheets in the pole tab portion are connected by welding marks, a portion of the welding marks is located in the first stacked portion, and the remaining portion is located in the second stacked portion.

16. A battery cell, characterized in that: include: A shell, a pole, and an electrode assembly according to any one of claims 1 to 15, wherein the pole is provided in the shell, the active material coating portion is accommodated in the shell, and the pole ear portion is electrically connected to the pole.

17. The battery cell according to claim 16, characterized in that: A position of the pole lug portion electrically connected to the pole is formed as a connection portion, and the connection portion includes a portion falling on the first stacking portion and a portion falling on the second stacking portion.

18. The battery cell according to claim 17, characterized in that: The pole is provided with a receiving groove, and at least a part of the pole ear portion is received in the receiving groove.

19. The battery cell according to claim 18, characterized in that: A accommodating cavity is formed in the shell, and the accommodating groove is open in a direction away from the accommodating cavity. A connecting hole is provided on the pole, and the connecting hole passes through a groove wall on one side of the accommodating groove close to the accommodating cavity and connects the accommodating cavity with the accommodating groove, and the pole ear portion is penetrated through the connecting hole.

20. The battery cell according to claim 19, characterized in that: It also includes a pole cover plate, which is arranged on the pole to cover the notch of the receiving groove, and has a liquid injection hole connected to the receiving groove, and has a sealing structure for blocking the liquid injection hole.

21. A battery, characterized in that: The invention comprises a battery cell according to any one of claims 16 to 20.

22. An electrical device, characterized in that: Comprising a battery according to claim 21.

23. A method for processing an electrode assembly, characterized in that: Includes steps: The plurality of tab sheets connected to the active material coating portion are stacked and partially staggered; Bend a first portion of the offset region of the multi-layered pole tab sheets toward a remaining second portion of the offset region in a direction close to an overlapping region of the multi-layered pole tab sheets in the pole tab portion, so that the first portion and the second portion are stacked; The multilayer tab sheets in the first and second stacked parts are connected to form a second stacked portion, and the multilayer tab sheets in the overlapping area are connected to form a first stacked portion; the first stacked portion and the second stacked portion together form a tab portion of the electrode assembly.

24. The method for processing an electrode assembly according to claim 23, characterized in that: The method further comprises the step of welding the multiple layers of pole tab sheets in the first part and the second part which are stacked after being bent to form the second stacked part.

25. The method for processing an electrode assembly according to claim 23 or 24, characterized in that: The method further comprises the steps of: welding the pole ear portion, welding the multiple pole ear sheets in the overlapping area to form the first stacked portion, and connecting the first stacked portion with the second stacked portion by welding.

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