Electrode assembly and its related battery, device, manufacturing method and manufacturing device

Abstract

An electrode assembly (10) and its related battery (400), device, manufacturing method and manufacturing device (500). The electrode assembly (10) comprises a plurality of first pole pieces (1) and at least one second pole piece (2), the first pole pieces (1) and the second pole pieces (2) are opposite in polarity, the plurality of first pole pieces (1) and the at least one second pole piece (2) are wound to form a winding structure around a winding axis (K), in the winding structure, the plurality of first pole pieces (1) and the at least one second pole piece (2) are arranged in a stacking manner along a direction perpendicular to the winding axis (K), each of the plurality of first pole pieces (1) comprises a first current collector (11) and a first active material layer (12) arranged on a stacking surface of the first current collector (11), the first current collector (11) comprises a first main body portion (111) provided with the first active material layer (12) and at least one first tab (112) protruding from the first main body portion (111) along the winding axis (K); wherein each of the at least one first tab (112) and the first main body portion (111) are distributed side by side along the winding axis (K). The winding turns of the electrode assembly (10) are reduced, and the dislocation amount of the first tab (112) in the circumferential direction after winding can be reduced.

Description

Technical Field

[0001] This disclosure relates to the field of batteries, and in particular to an electrode assembly and related batteries, devices, manufacturing methods and manufacturing apparatus. Background Technology

[0002] Lithium-ion batteries have advantages such as small size, high energy density, high power density, high cycle life, and long storage time. They are widely used in electronic devices, electric vehicles, electric toys, and electric equipment. For example, lithium-ion batteries are widely used in mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools.

[0003] Electrode components are an important part of lithium-ion batteries. Due to their simple manufacturing process and high production efficiency, wound electrode components have been widely used in lithium-ion batteries.

[0004] However, in order to improve the volumetric energy density of lithium-ion batteries, the electrode components are usually wound multiple times. During the multiple winding process, the tabs are easily misaligned, which affects the connection with the current collector. Summary of the Invention

[0005] The purpose of this disclosure is to provide an electrode assembly and related batteries, devices, manufacturing methods and manufacturing apparatus to improve the problem of electrode misalignment caused by multiple windings.

[0006] The first aspect of this disclosure provides an electrode assembly, including multiple first electrode plates and at least one second electrode plate, wherein the first electrode plates and the second electrode plates have opposite polarities, and the multiple first electrode plates and at least one second electrode plate are wound around a winding axis to form a winding structure, wherein the multiple first electrode plates and at least one second electrode plate are stacked in a direction perpendicular to the winding axis.

[0007] Each of the multiple first electrode sheets includes a first current collector and a first active material layer disposed on the superimposed surface of the first current collector. The first current collector includes a first main body portion disposed on the first active material layer and at least one first electrode tab protruding from the first main body portion along the winding axis direction.

[0008] In this configuration, each of the first electrode tabs and the first main body portion are arranged side by side along the winding axis.

[0009] In some embodiments, each first electrode includes a plurality of first tabs spaced apart.

[0010] In some embodiments, in the winding structure, each first electrode sheet has at least one tab on each of its turns.

[0011] In some embodiments, any two of the first electrodes at least partially overlap.

[0012] In some embodiments, the winding structure is flat and includes a flat region and turning regions located on both sides of the flat region; all first tabs are located in the flat region.

[0013] In some embodiments, the flat region includes a first sub-flat region and a second sub-flat region that are substantially parallel and symmetrically distributed about the winding axis;

[0014] All first pole pieces are located in the first sub-flat region or the second sub-flat region; or

[0015] Of all the first pole ears, one part is located in the first sub-flat region and the other part is located in the second sub-flat region.

[0016] In some embodiments, at least two of the multiple first electrodes have different winding start positions; and / or, at least two of the multiple first electrodes have different winding end positions.

[0017] In some embodiments, the electrode assembly includes a plurality of second electrodes, wherein at least two of the plurality of second electrodes have different winding start positions; and / or at least two of the plurality of second electrodes have different winding end positions.

[0018] In some embodiments, the electrode assembly includes multiple second electrode sheets, and the wound structure is flat, including a straight region and a turning region located on both sides of the straight region;

[0019] Wherein, the winding end of at least one of the multiple first electrode sheets is located in the turning zone; and / or the winding end of at least one of the multiple second electrode sheets is located in the turning zone.

[0020] In some embodiments, the number of layers of the first electrode and the second electrode differs by no more than a preset number of layers in different radial directions of the winding structure.

[0021] A second aspect of this disclosure provides a battery including a housing and an electrode assembly as provided in any of the first aspects of this disclosure, the electrode assembly being disposed within the housing.

[0022] A third aspect of this disclosure provides a battery module comprising: a plurality of batteries as provided in the second aspect of this disclosure.

[0023] This disclosure provides a fourth aspect of a battery pack, including: a plurality of battery modules as provided in the third aspect of this disclosure.

[0024] The fifth aspect of this disclosure provides an apparatus for using a battery, comprising: a battery as provided in the second aspect of this disclosure, wherein the battery is used to provide electrical energy.

[0025] The sixth aspect of this disclosure provides a method for manufacturing an electrode assembly, comprising:

[0026] Provide multiple first electrodes and at least one second electrode, wherein the first and second electrodes have opposite polarities;

[0027] Multiple first electrode plates and at least one second electrode plate are wound around a winding axis to form a winding structure;

[0028] In the winding structure, the first electrode sheets of multiple first electrode sheets and the second electrode sheets of at least one second electrode sheet are stacked in a direction perpendicular to the winding axis; each first electrode sheet includes a first current collector and a first active material layer disposed on the stacking surface of the first current collector, the first current collector includes a first main body portion disposed on the first active material layer and at least one first electrode tab protruding from the first main body portion in the direction of the winding axis, and each of the at least one first electrode tab and the first main body portion are distributed side by side along the winding axis.

[0029] A seventh aspect of this disclosure provides an apparatus for manufacturing an electrode assembly, including an electrode placement mechanism and a winding mechanism. The electrode placement mechanism is configured to provide a plurality of first electrodes and at least one second electrode, the first electrodes and the second electrodes having opposite polarities. The winding mechanism is configured to wind the plurality of first electrodes and at least one second electrode around a winding axis to form a winding structure, wherein, in the winding structure, the first electrodes of the plurality of first electrodes and the second electrodes of the at least one second electrode are stacked in a direction perpendicular to the winding axis; each first electrode includes a first current collector and a first active material layer disposed on the stacking surface of the first current collector, the first current collector includes a first main body portion disposed of the first active material layer and at least one first tab protruding from the first main body portion along the winding axis direction, and each of the at least one first tab and the first main body portion are distributed side by side along the winding axis.

[0030] Based on the technical solution provided in this disclosure, the electrode assembly includes multiple first electrode plates, which is equivalent to reducing the length of the first electrode plates. This reduces the number of winding turns of the electrode assembly, thereby reducing the misalignment of the first electrode tabs in the circumferential direction after winding and facilitating connection with the current collector. Furthermore, the first electrode tabs and the first main body of this disclosure are distributed side by side along the winding axis, thereby increasing the area of ​​the first active material layer coated on the first current collector and thus improving the energy density of the electrode assembly.

[0031] Other features and advantages of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0032] The accompanying drawings, which are included to provide a further understanding of this disclosure and form part of this disclosure, illustrate exemplary embodiments of the present disclosure and are used to explain the disclosure, but do not constitute an undue limitation of the disclosure. In the drawings:

[0033] Figure 1 A schematic diagram of the exterior of some embodiments of a vehicle using the battery disclosed herein;

[0034] Figure 2 These are schematic diagrams illustrating the structure of some embodiments of the battery pack disclosed herein;

[0035] Figure 3 These are schematic diagrams illustrating the structure of some embodiments of the battery module disclosed herein;

[0036] Figure 4 This is an exploded view of some embodiments of the battery disclosed herein;

[0037] Figure 5 Side views of some embodiments of the electrode assembly of this disclosure in which the first and second electrodes are alternately arranged;

[0038] Figure 6 for Figure 5 Enlarged structural diagram at point B in the diagram;

[0039] Figure 7 This is a schematic diagram of the structure of the first electrode in the electrode assembly of this disclosure;

[0040] Figure 8 This is a schematic diagram of the structure of the second electrode in the electrode assembly of this disclosure;

[0041] Figure 9 , Figure 10 , Figure 11 , Figure 12 and Figure 13 These are cross-sectional views of the first, second, third, fourth, and fifth embodiments of the flat electrode assembly disclosed herein, respectively, in a plane perpendicular to the winding axis.

[0042] Figure 14 , Figure 15 , Figure 16 and Figure 17 These are cross-sectional views of the first, second, third, and fourth embodiments of the cylindrical electrode assembly disclosed herein, respectively, in a plane perpendicular to the winding axis.

[0043] Figure 18 A schematic flowchart illustrating some embodiments of the electrode assembly manufacturing method disclosed herein;

[0044] Figure 19 This is a schematic diagram of the structure of some embodiments of the manufacturing apparatus for the electrode assembly of this disclosure. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this disclosure are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this disclosure are used to distinguish different objects and not to describe a particular order or hierarchy.

[0047] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0048] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0049] In this disclosure, "multiple" refers to two or more items; similarly, "multiple groups" refers to two or more groups, and "multiple pieces" refers to two or more pieces.

[0050] The electrode assemblies and manufacturing methods thereof, batteries, battery modules, and battery packs described in the embodiments of this disclosure are applicable to various battery-using devices, such as mobile phones, laptops, electric vehicles, electric cars, ships, spacecraft, electric toys, and power tools, etc. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0051] The electrode assemblies, batteries, battery modules, and battery packs described in this disclosure are not limited to the devices described above, but can also be applied to all devices that use batteries. However, for the sake of brevity, the following embodiments are all illustrated using electric vehicles as examples.

[0052] For example, such as Figure 1 The diagram shown is a structural schematic of a vehicle 100 according to an embodiment of this disclosure. The vehicle 100 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery pack 200 can be installed inside the vehicle 100, for example, at the bottom, front, or rear of the vehicle. The battery pack 200 can be used to power the vehicle 100. For example, the battery pack 200 can serve as the operating power source for the vehicle 100's electrical system, such as meeting the power requirements for starting, navigation, and operation. In another embodiment of this disclosure, the battery pack 200 can not only serve as the operating power source for the vehicle 100 but also as the driving power source, replacing or partially replacing gasoline or natural gas to provide driving power for the vehicle 100.

[0053] To meet different power demands, the battery pack 200 may include one or more battery modules, wherein the multiple battery modules may be connected in series, parallel, or a combination thereof. A combination thereof refers to a mix of series and parallel connections. For example, ... Figure 2The diagram shown is a structural schematic of a battery pack 200 according to another embodiment of the present disclosure. The battery pack 200 includes a first housing 201, a second housing 202, and a plurality of battery modules 300. The shapes of the first housing 201 and the second housing 202 are determined according to the combined shape of the plurality of battery modules 300. Both the first housing 201 and the second housing 202 have an opening. For example, both the first housing 201 and the second housing 202 can be hollow cuboids and each has only one face as an opening, that is, this face does not have a housing wall so that the inside and outside of the housing are connected. The first housing 201 and the second housing 202 are fastened together at the opening to form a closed outer shell of the battery pack 200. The plurality of battery modules 300 are connected in parallel, in series, or in a mixed combination and placed inside the outer shell formed by the fastening of the first housing 201 and the second housing 202.

[0054] In another embodiment of this disclosure, when the battery pack 200 includes a battery module 300, the battery module 300 is placed inside the outer shell formed by the first housing 201 and the second housing 202 being fastened together.

[0055] The electricity generated by one or more battery modules 300 is led out through the housing via a conductive mechanism.

[0056] Depending on different power requirements, the battery module 300 may also include one or more batteries, such as Figure 3 As shown, the battery module 300 includes multiple batteries 400, which can be connected in series, parallel, or mixed connections to achieve a larger capacity or power. For example, the batteries 400 may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, or magnesium-ion batteries, but are not limited to these. The batteries 400 may be cylindrical, flat, cuboid, or other shapes.

[0057] In another embodiment of this disclosure, multiple batteries 400 may be stacked together, and the multiple batteries 400 may be connected in series, parallel, or mixed. In another embodiment of this disclosure, each battery 400 may be square, cylindrical, or other shapes. For example, Figure 4The diagram shows a structural schematic of a battery 400 according to another embodiment of this disclosure. The battery 400 includes one or more electrode assemblies 10, a housing 20, and an end cap assembly 40. The housing 20 is shaped according to the combination of the one or more electrode assemblies 10. For example, the housing 20 can be a hollow cuboid, cube, or cylinder, and one side of the housing 20 has an opening so that one or more electrode assemblies 10 can be placed inside the housing 20. For example, when the housing 20 is a hollow cuboid or cube, one plane of the housing 20 is the opening, that is, this plane does not have a housing wall, allowing communication between the inside and outside of the housing 20. When the housing 20 is a hollow cylinder, the circular side of the housing 20 is the opening, that is, this circular side does not have a housing wall, allowing communication between the inside and outside of the housing 20. The end cap assembly 40 is connected to the housing 20 at the opening to form a closed outer shell for placing the battery 400, and the housing 20 is filled with electrolyte.

[0058] The end cap assembly 40 includes an end cap 41 and a first terminal 42 and a second terminal 43 disposed on the end cap 41. The end cap 41 is basically flat. The first terminal 42 and the second terminal 43 are located on the flat surface of the end cap 41 and pass through the flat surface of the end cap 41. Each of the first terminal 42 and the second terminal 43 is provided with a current collector 30. The current collector 30 is located between the end cap 41 and the electrode assembly 10.

[0059] For example, Figure 4 As shown, each electrode assembly 10 has a first tab 112 and a second tab 212. The first tab 112 of one or more electrode assemblies 10 is connected to a first terminal 42 via a current collector 30, and the second tab 212 of one or more electrode assemblies 10 is connected to a second terminal 43 via another current collector 30. Furthermore, the electrode assembly 10 also includes a welding protective sheet 50 disposed between the tab and the corresponding current collector 30.

[0060] In another embodiment of this disclosure, an explosion-proof valve 44 may be provided on the flat surface of the end cap 41. The explosion-proof valve 44 may be part of the flat surface of the end cap 41 or welded to the flat surface of the end cap 41. The explosion-proof valve 44 has a groove, the depth of which is less than the thickness of the other areas of the explosion-proof valve 44 except for the groove, so as not to penetrate the explosion-proof valve 43. That is, under normal conditions, the explosion-proof valve 44 is sealed to the end cap 41. The end cap assembly 40 is connected to the housing 20 through the end cap 41 at the opening of the housing 20 to form a shell for placing the battery 400. The space formed by the shell is sealed and airtight. Inside the shell, when the battery 400 produces too much gas, the gas expands and the gas pressure inside the shell rises to a value exceeding a preset value. The explosion-proof valve 44 cracks at the groove, causing communication between the inside and outside of the shell. The gas is released outward through the crack of the explosion-proof valve 44, thereby preventing an explosion.

[0061] In this battery 400, depending on actual usage requirements, the electrode assembly 10 can be configured as a single unit or multiple units, such as... Figure 4 As shown, two independent electrode assemblies 10 are provided inside the battery 400.

[0062] In some embodiments, such as Figure 5 As shown, the electrode assembly 10 includes multiple first electrode plates 1 and at least one second electrode plate 2. The first electrode plates 1 and the second electrode plates 2 have opposite polarities; for example, the first electrode plate 1 is a positive electrode plate and the second electrode plate 2 is a negative electrode plate, or vice versa. The multiple first electrode plates 1 and at least one second electrode plate 2 are wound around a winding axis K to form a winding structure. In the winding structure, the multiple first electrode plates 1 and at least one second electrode plate 2 are stacked in a direction perpendicular to the winding axis K.

[0063] The number of first electrode 1 and second electrode 2 can be the same or different. In some embodiments, the sum of the number of all first electrode 1 and all second electrode 2 is greater than or equal to 3. For example, electrode assembly 10 includes 2, 3 or 4 first electrode 1 and 1, 2, 3 or 4 second electrode 2.

[0064] In the embodiments of this disclosure, each first electrode 1 and each second electrode 2 has a substantially similar shape. For example, after the winding structure is unwound, the first electrode 1 and the second electrode 2 are essentially long strips, for example, long strips 5-20 meters in length. The lengths of the first electrode 1 and the second electrode 2 differ within a predetermined range, and their widths are substantially the same. A winding structure is obtained by stacking multiple first electrode 1s and at least one second electrode 2 and then winding them along the long strip direction. This winding structure has a winding axis K, and the stacking surface of the multiple first electrode 1s and at least one second electrode 2 is substantially parallel to the winding axis K.

[0065] In another embodiment of this disclosure, the stacking of the multiple first electrode sheets 1 and at least one second electrode sheet 2 can take various forms. For example, when there are two or more first electrode sheets 1 and two or more second electrode sheets 2, the unwound winding structure can be stacked alternately in the form of one first electrode sheet 1 and one second electrode sheet 2. As another example, when there are two or more first electrode sheets 1 and at least one second electrode sheet 2, the unwound winding structure can be stacked alternately in the form of two or more first electrode sheets 1 and one second electrode sheet 2.

[0066] When multiple first electrode plates 1 and at least one second electrode plate 2 are stacked, a diaphragm 3 is provided between any adjacent first electrode plate 1 and second electrode plate 2 to separate the adjacent first electrode plate 1 and second electrode plate 2 so as not to short-circuit with each other.

[0067] In another embodiment of this disclosure, electrodes of different polarities are adjacent, for example, the first electrode 1 and the second electrode 2 are adjacent, meaning that there are no other electrodes between the first electrode 1 and the second electrode 2 but there is at least one layer of diaphragm 3. For example, there are no other first electrode 1 or second electrode 2 between the first electrode 1 and the second electrode 2. It can also be understood that the first electrode 1 and the second electrode 2 are most directly adjacent to each other. For example, based on a polarity electrode, the first layer of electrodes of different polarities adjacent to the polarity electrode are called adjacent electrodes.

[0068] In another embodiment of this disclosure, two electrodes of the same polarity being adjacent means that there is only one electrode of another polarity between the two electrodes of the same polarity. For example, two first electrodes 1 being adjacent means that there is only one second electrode 2 between the two first electrodes 1, and two second electrodes 2 being adjacent means that there is only one first electrode 1 between the two second electrodes 2. In another embodiment of this disclosure, when there are no other electrodes of different polarities between two electrodes of the same polarity, the two electrodes of the same polarity can be regarded as one electrode.

[0069] In another embodiment of this disclosure, when there are no other electrodes or diaphragms of different polarities between two or more electrodes of the same polarity, the two electrodes of the same polarity can be regarded as a group of electrodes. When stacking, the electrode group of the same polarity is stacked alternately with another electrode group of different polarities or a single electrode. For example, two or more first electrodes form a first electrode group, and two or more second electrodes form a second electrode group. The stacking can be: the first electrode group and the second electrode group are stacked alternately, the first electrode group and a single second electrode are stacked alternately, or the second electrode group and a single first electrode are stacked alternately.

[0070] Since a group of electrodes of the same polarity can be regarded as a single electrode, for the sake of convenience, the term "a single electrode" in the following description can refer to either a single electrode or a group of electrodes of the same polarity.

[0071] However, regardless of how they are stacked, at least one diaphragm 3 is provided between adjacent electrodes of different polarities.

[0072] In another embodiment of this disclosure, the diaphragm 3 includes a diaphragm base layer and a functional layer. The diaphragm base layer may be at least one of polypropylene, polyethylene, ethylene-propylene copolymer, polybutylene terephthalate, etc., and the functional layer may be a mixture of ceramic oxide and binder. In another embodiment of this disclosure, after the wound structure is unwound, the diaphragm 3 is a separate thin film and is substantially in the shape of a long strip, for example, a long strip 5-20 meters long. In another embodiment of this disclosure, the diaphragm 3 is coated on the surface of the first electrode 1 and / or the second electrode 2, that is, the diaphragm 3 and the first electrode 1 and / or the second electrode 2 are an integral structure.

[0073] In another embodiment of this disclosure, such as Figure 5 As shown, in the winding structure, the first electrode 1 and the second electrode 2 are stacked alternately in sequence, where AA is the direction in which multiple first electrode 1s and at least one second electrode 2 are stacked together, and K is the winding axis K of the winding structure.

[0074] In another embodiment of this disclosure, such as Figure 6 As shown, each of the multiple first electrode plates 1 includes a first current collector 11 and a first active material layer 12 disposed on the superimposed surface of the first current collector 11. The first current collector 11 includes a first main body portion 111 on which the first active material layer 12 is disposed and a first tab 112 protruding from the first main body portion 111 along the winding axis K. The first tab 112 and the first main body portion 111 are arranged side-by-side along the winding axis K. The second electrode plate 2 includes a second current collector 21 and a second active material layer 22 disposed on the superimposed surface of the second current collector 21. The second current collector 21 includes a second main body portion 211 on which the second active material layer 22 is disposed and a second tab 212 protruding from the second main body portion 211 along the winding axis K.

[0075] In another embodiment of this disclosure, when multiple first pole pieces 1 and at least one second pole piece 2 are superimposed on each other, that is, in the winding structure, the first pole tab 112 of the first pole piece 1 and the second pole tab 212 of the second pole piece 2 can be located on the same side of the winding structure along the winding axis K, or they can be located on different sides.

[0076] In another embodiment of this disclosure, any two of the first tabs 112 at least partially overlap. For example, one of the plurality of first electrodes 1 has one first tab 112, and another of the plurality of first electrodes 1 has one first tab 112, and these two first tabs 112 at least partially overlap. As another example, one of the plurality of first electrodes 1 has a plurality of first tabs 112, and any two of the plurality of first tabs 112 at least partially overlap. As yet another example, one of the plurality of first electrodes 1 has a plurality of first tabs 112, and another of the plurality of first electrodes 1 has a plurality of first tabs 112, and any one of the first tabs 112 of one electrode at least partially overlaps with any one of the first tabs 112 of the other electrode.

[0077] As described above, in order to achieve the same energy, the electrode assembly of this embodiment is equivalent to dividing a single first electrode sheet whose length is equal to the sum of the lengths of multiple first electrode sheets 1 into multiple first electrode sheets 1 and winding them in parallel. The electrode assembly of this embodiment has multiple electrodes of the same polarity inside, and the internal resistance of the electrode assembly is smaller, thereby reducing the heat generated by the electrode assembly during use and improving the performance of the electrode assembly.

[0078] Moreover, compared with the alignment of multiple tabs on the same type of electrode when a single electrode with a length equal to the sum of multiple first electrode plates 1 is wound, in the electrode assembly of this embodiment, the tabs on multiple first electrode plates 1 are stacked and aligned side by side before being wound, and the length of the electrode plate is shortened, and the number of winding turns is reduced. Therefore, the control capability of tab misalignment during the winding process can be improved, the amount of misalignment between multiple first electrode plates 112 after winding can be reduced, and it is easier to connect with the current collector, thereby improving the current carrying capacity of the tabs and improving the quality of the electrode assembly.

[0079] Furthermore, in related technologies, the active material layer is not coated on one side of the first main body portion in the direction perpendicular to the winding axis K, and the electrode tab is welded to this area. In this embodiment, the first electrode tab 112 and the first main body portion 111 are distributed side by side along the winding axis K, and the first active material layer is provided on both sides of the first main body portion in the direction perpendicular to the winding axis K. Therefore, the area of ​​the first active material layer 12 coated on the first current collector 11 is increased, thereby improving the energy density of the electrode assembly.

[0080] In another embodiment of this disclosure, after the winding structure is unwound, the structure of the first electrode 1 is as follows: Figure 7 As shown, each first electrode 1 in this embodiment includes a plurality of first tabs 112. By providing a plurality of first tabs 112, the current carrying capacity can be improved.

[0081] In another embodiment of this disclosure, the first tab 112 is formed by cutting an uncoated area of ​​the first current collector 11. In the wound structure after winding, each first electrode sheet 1 is provided with at least one first tab 112 on each turn. For example, each first electrode sheet 1 is provided with one or two first tabs 112 on each turn.

[0082] In another embodiment of this disclosure, after the electrode assembly 10 is wound and formed, a plurality of first tabs 112 are stacked together and welded to the current collector 30.

[0083] To avoid the unwelded areas of multiple first tabs 112 being scattered after welding, and because the first tabs 112 are thin, they are easily deformed and pressed between the first electrode 11 and the second electrode 12 during battery assembly, thus causing a short circuit risk.

[0084] In this embodiment, the first electrode 1 is provided with an insulating layer 15, which can serve as an insulating protection function. For example, referring to... Figure 7 The insulating layer 15 is disposed on the surface of the root of the first electrode tab 112. The insulating layer 15 plays the role of insulation protection. Even when the first electrode tab 112 is inserted between the first electrode plate 1 and the second electrode plate 2, the insulating layer 15 can effectively separate the first electrode tab 112 from the second electrode plate 2, thereby reducing the risk of short circuit and improving safety performance.

[0085] Reference Figure 7 The insulating layer 15 includes a first portion 15a and a second portion 15b. The first portion 15a is disposed (e.g., coated) on the overlapping surface of the first body portion 111 and connected to the end of the first active material layer 12 near the first tab 112. The second portion 15b extends from the end of the first portion 15a away from the first active material layer 12 and is disposed (e.g., coated) on the overlapping surface of the first tab 112. The second portion 15b can cover the root region of the first tab 112 near the first body portion 111 and effectively reduce the risk of the root region of the first tab 112 contacting the first active material layer 12.

[0086] For example, the first active material layer 12 and the first portion 15a are distributed on the superimposed surface of the first main body 111 along both ends of the winding axis K, and the first tab 112 and the first portion 15a are located on the same end of the first main body 111. For example, the first tab 112 extends from the first portion 15a to the outside of the first main body 111 along the winding axis K.

[0087] For example, the first active material layer 12 and the first part 15a are distributed on both ends of the winding axis K on the superimposed surface of the first main body 111. It can also be understood that the first active material layer 12 and the first part 15a are basically parallel regions on the superimposed surface of the first main body 111 and are distributed in two layers on the superimposed surface of the first main body 111 along the winding axis K. That is, the first active material layer 12 and the first part 15a are basically parallel on the superimposed surface of the first main body 111 along the long strip direction of the positive electrode sheet 1 and are distributed in two layers.

[0088] The insulating layer 15 comprises inorganic fillers and adhesives. The inorganic fillers include one or more of boehmite, alumina, magnesium oxide, titanium dioxide, zirconium oxide, silicon dioxide, silicon carbide, boron carbide, calcium carbonate, aluminum silicate, calcium silicate, potassium titanate, and barium sulfate. The adhesives include one or more of polyvinylidene fluoride, polyacrylonitrile, polyacrylic acid, polyacrylate, polyacrylic acid-acrylate, polyacrylonitrile-acrylic acid, and polyacrylonitrile-acrylate.

[0089] In this embodiment, any two first tabs at least partially overlap. The reduced number of winding turns in the electrode assembly 10 in this embodiment decreases the misalignment between the multiple first tabs 112 after winding, thereby improving the current-carrying capacity of the tabs.

[0090] Before winding, the structure of the second electrode 2 is as follows: Figure 8 As shown. In this embodiment, the second electrode 12 further includes a third active material layer 23, which is disposed (e.g., coated) on the surface of the second electrode tab 212 and connected to the area of ​​the second active material layer 22. For example, the third active material layer 23 is disposed (e.g., coated) on the root surface of the second electrode tab 212. The third active material layer 23 and the second active material layer 22 are integrally formed.

[0091] During battery assembly, the uncoated areas of the multiple second tabs 212 are gathered together and welded to the current collector 30. The third active material layer 23 has a large elastic modulus, which can effectively support the second tabs 212 and reduce the risk of the second tabs 212 being inserted between the first electrode 1 and the second electrode 2.

[0092] Specifically, in this embodiment, the first current collector 11 is an aluminum foil, the first active material layer 12 includes ternary materials such as lithium manganese oxide or lithium iron phosphate; the second current collector 21 is a copper foil, and the second active material layer 22 includes graphite or silicon.

[0093] In this embodiment, both the first electrode 1 and the second electrode 2 are multiple pieces. For example, the number of the first electrode 1 and the second electrode 2 is selected as 2 to 3 pieces, so as to ensure easy winding while reducing the length of the electrode and preventing a significant increase in the winding force required when the number of electrodes is large or the active material coated on the electrode surface from falling off.

[0094] The electrode assembly of this embodiment has a flat winding structure and includes a flat region and turning regions located on both sides of the flat region. The overlapping surfaces of the electrodes in the flat region are substantially parallel and substantially parallel to the winding axis K. The flat region includes a first sub-flat region and a second sub-flat region that are substantially parallel and symmetrically distributed with respect to the winding axis K along a plane perpendicular to the winding axis K. The two turning regions are located on both sides of the flat region formed by the combination of the first sub-flat region and the second sub-flat region.

[0095] In this embodiment, all the first tabs 112 are located in the flat region. This increases the contact area between multiple first tabs 112 when they are stacked and connected, improving current carrying capacity. Furthermore, in this embodiment, all the first tabs 112 are located in the first sub-flat region. While ensuring the current carrying capacity of the first tabs 112, the thickness of the stacked first tabs 112 can be reduced, thereby reducing the space occupied by the first tabs 112.

[0096] In embodiments not shown in the accompanying drawings, all first tabs may also be located in the second sub-flat region. Alternatively, a portion of all first tabs may be located in the first sub-flat region, and another portion in the second sub-flat region.

[0097] In another embodiment of this disclosure, the electrode assembly 10 includes a plurality of first electrode sheets 1, wherein at least two of the first electrode sheets 1 have different winding start positions. Furthermore, at least two of the first electrode sheets 1 have different winding end positions. For example, all the first electrode sheets 1 have different winding start positions and different winding end positions.

[0098] In another embodiment of this disclosure, the electrode assembly 10 includes a plurality of second electrode sheets 2, wherein at least two of the second electrode sheets 2 have different winding start positions and at least two of the second electrode sheets 2 have different winding end positions. For example, all the second electrode sheets 2 have different winding start positions and different winding end positions.

[0099] During use, the electrode assembly 10 expands, exerting a force on the housing 20 after expansion. Simultaneously, the housing 20 exerts a reaction force on the electrode assembly 10. Because the electrode assembly 10 of this disclosure increases the number of layers of the first electrode 1 and the second electrode 2, this structure can prevent the formation of thick steps at the winding ends E of multiple first electrode 1s or multiple second electrode 2s. When the outer layer of the winding structure is subjected to the reaction force of the housing 20, it can alleviate the problem of stress concentration at the winding ends E of the electrode, ensuring uniform stress distribution across different circumferential positions of the winding structure. This prevents large deformation of the winding structure or the shedding of active material in localized areas of high stress, thereby improving the long-term performance and reliability of the battery.

[0100] In another embodiment of this disclosure, the electrode assembly includes a plurality of first electrode plates 1 and a plurality of second electrode plates 2, wherein at least two of the first electrode plates 1 have different winding start positions S, for example, the winding start positions S of all the first electrode plates 1 are different from each other; and / or, at least two of the second electrode plates 2 have different winding start positions S', for example, the winding start positions S' of all the second electrode plates 2 are different from each other.

[0101] The electrode assembly 10 expands during use. Because the electrode assembly 10 of this disclosure has different positions for the first winding start ends S of at least two first electrode sheets 1 and / or different positions for the second winding start ends S' of at least two second electrode sheets 2, i.e., the first winding start ends S of at least two first electrode sheets 1 are staggered circumferentially in the winding structure, and / or the second winding start ends S' of at least two second electrode sheets 2 are staggered circumferentially in the winding structure, the different winding start ends of the first electrode sheets 1 and / or second electrode sheets 2 can prevent the formation of thick steps at the winding start ends of multiple first electrode sheets 1 or multiple second electrode sheets 2. This can alleviate the problem of stress concentration at the winding start ends of the electrode sheets, ensure uniform stress distribution in different circumferential positions of the winding structure, prevent large deformation of the winding structure, or the shedding of active material in localized areas of high stress, thereby improving the long-term performance and reliability of the battery.

[0102] In another embodiment of this disclosure, the winding end of at least one of the plurality of first electrode sheets 1 is located in the turning region. The winding end of at least one of the plurality of second electrode sheets 2 is located in the turning region.

[0103] The winding ends of the first electrode 1 and the second electrode 2 are both located in the turning area, which can reduce the difference in the number of electrode layers in the first sub-straight area and the second sub-straight area. When the electrode assembly 10 expands and contacts the housing 20, the inner wall of the housing 20 applies a reaction force to the two planes of the electrode assembly 10, which can make the stress on the electrodes in the first sub-straight area and the second sub-straight area more consistent.

[0104] In another embodiment of this disclosure, the number of electrode layers in different radial directions of the winding structure does not differ by a preset number of layers. For example, the preset number of layers is less than or equal to the sum of the number of multiple first electrode sheets 1 and multiple second electrode sheets 2. For instance, after two first electrode sheets 1 and two second electrode sheets 2 are wound, the number of electrode layers is 8 in one radial direction of the winding structure, and the number of electrode layers is between a minimum of 8 and a maximum of 12 in another radial direction of the winding structure. That is, the preset number of layers is less than or equal to the sum of the number of two first electrode sheets 1 and two second electrode sheets 2: 4.

[0105] When the electrode assembly 10 expands and comes into contact with the housing 20, the housing 20 applies a reaction force to the electrode assembly 10. By ensuring that the number of electrode layers does not differ by a preset number in different radial directions of the winding structure, the force on the electrode assembly 10 is made more uniform in all circumferential directions, preventing significant performance differences in various parts of the electrode assembly 10 during use. For example, if the first electrode 1 has two pieces and the second electrode 2 has two pieces, with a preset number of layers less than or equal to four, the smaller the difference in the number of electrode layers, the more uniform the force on the electrode assembly 10 is in all circumferential directions of the winding structure.

[0106] The electrode assembly 10 may include at least two first electrode plates 1 and at least two second electrode plates 2, but for ease of description, the following embodiments will be described using two first electrode plates 1 and two second electrode plates 2 as examples.

[0107] The appearance of the winding structure of the electrode assembly 10 can be cylindrical, flat, elliptical, cubic, cuboid or any other shape. However, for the sake of convenience, the following description will take the winding structure of the electrode assembly 10 as a flat shape and a cylindrical shape as examples.

[0108] like Figure 9 The diagram shows a cross-sectional view of a flat electrode assembly perpendicular to the winding axis K, according to another embodiment of this disclosure. The electrode assembly 120 includes a first negative electrode 1201, a second negative electrode 1202, a first positive electrode 1203, a second positive electrode 1204, and multiple separators 1205. The first negative electrode 1201, the first positive electrode 1203, the second negative electrode 1202, and the second positive electrode 1204 are alternately stacked, and the first negative electrode 1201 and the first positive electrode 1204 are... The positive electrode 1203 is separated by a separator 1205, the first positive electrode 1203 and the second negative electrode 1202 are separated by another separator 1205, and the second negative electrode 1202 and the second positive electrode 1204 are separated by another separator 1205. All the first negative electrode 1201, the second negative electrode 1202, the first positive electrode 1203, the second positive electrode 1204 and the multiple separators 1205 are stacked and wound around the winding axis K to form a flat winding structure.

[0109] In this embodiment, the structure and position of the tabs on the positive and negative electrodes of the electrode assembly 120 can be referenced from the aforementioned description. Figure 5-8 The relevant details described in the embodiments regarding the first electrode tab of the first electrode and the second electrode tab of the second electrode are not repeated here.

[0110] In this embodiment, the number of electrode layers in the winding structure of the electrode assembly 120 does not differ by a preset number at different radial directions, i.e., at different positions circumferentially along the winding structure. This can also be referred to the aforementioned... Figure 5-8 The relevant content described in the embodiments will not be repeated here.

[0111] In the winding structure, the innermost ring is the ring surrounded by the first negative electrode 1201, and the outermost ring is the ring surrounded by the second negative electrode 1202.

[0112] In this embodiment, the winding structure of the electrode assembly 120 includes a flat region 10A and turning regions 10B located on both sides of the flat region 10A. The superimposed surfaces of the electrode sheets in the flat region 10A are basically parallel planes and basically parallel to the winding axis. Here, the plane is not a plane in the strict sense and a certain error is allowed. The flat region 10A includes a first sub-flat region 10A1 and a second sub-flat region 10A2 that are basically parallel and symmetrically distributed with respect to the winding axis K along a plane perpendicular to the winding axis K. The two turning regions 10B are located on both sides of the flat region 10A formed by the combination of the first sub-flat region 10A1 and the second sub-flat region 10A2.

[0113] In the winding structure of the electrode assembly, all the negative tabs of the first negative electrode 1201 and all the negative tabs of the second negative electrode 1202 can be located in the flat region 10A. For example, all the negative tabs are located in the first sub-flat region 10A1 or all the negative tabs are located in the second sub-flat region 10A2. Alternatively, some of the negative tabs are located in the first sub-flat region 10A1 and another part of the negative tabs are located in the second sub-flat region 10A2. However, the negative tabs located in the same region at least partially overlap in the direction perpendicular to the winding axis, for example, substantially overlap.

[0114] All positive tabs of the first positive electrode 1203 and all positive tabs of the second positive electrode 1204 can be located in the flat region 10A. For example, all positive tabs may be located in the first sub-flat region 10A1 or all positive tabs may be located in the second sub-flat region 10A2. Alternatively, some positive tabs may be located in the first sub-flat region 10A1 and another part of the positive tabs may be located in the second sub-flat region 10A2. However, positive tabs located in the same region may at least partially overlap in the direction perpendicular to the winding axis, for example, substantially overlap.

[0115] The first winding start S of the first positive electrode 1203 and the second positive electrode 1204 are in the same position. For example, the first winding start S of the first positive electrode 1203 and the second positive electrode 1204 are both located in the sub-straight region (e.g., the first sub-straight region 10A1) on the same side of the straight region 10A, and the first winding start S of the first positive electrode 1203 and the second positive electrode 1204 are flush.

[0116] The second winding start point S' of the first negative electrode 1201 and the second negative electrode 1202 are also in the same position. For example, the second winding start point S' of the first negative electrode 1201 and the second negative electrode 1202 are both located in the sub-straight region (e.g., the first sub-straight region 10A1) on the same side of the straight region 10A, and the second winding start point S' of the first negative electrode 1201 and the second negative electrode 1202 are flush.

[0117] In the opposite direction of the winding direction, the second winding start S' of the first negative electrode 1201 extends beyond the first winding start S of the first positive electrode 1204. The second winding start S' of the second negative electrode 1202 extends beyond the first winding start S of the second positive electrode 1203.

[0118] The first winding ends E of the first positive electrode 1203 and the second positive electrode 1204 are at the same position. For example, the first winding ends E of the first positive electrode 1203 and the second positive electrode 1204 are both located in the same turning area (e.g., the first turning area 10B1), and the first winding ends E of the first positive electrode 1203 and the second positive electrode 1204 are flush.

[0119] The second winding ends E' of the first negative electrode 1201 and the second negative electrode 1202 are also in the same position. For example, the second winding ends E' of the first negative electrode 1201 and the second negative electrode 1202 are both located in the same turning area (e.g., the first turning area 10B1), and are also located in the same turning area (e.g., the first turning area 10B1) as the first winding ends E of the first positive electrode 1203 and the second positive electrode 1204, and the second winding ends E' of the first negative electrode 1201 and the second negative electrode 1202 are flush.

[0120] Along the winding direction, the second winding end E' of the first negative electrode 1201 extends beyond the first winding end E of the second positive electrode 1204, and the second winding end E' of the second negative electrode 1202 extends beyond the first winding end E of the first positive electrode 1203.

[0121] The winding structure of the electrode assembly described above enables the length differences of multiple electrode sheets to be close before winding, making it easy to wind.

[0122] like Figure 10 The diagram shows a cross-section of a flat electrode assembly perpendicular to the winding axis K, according to another embodiment of this disclosure. The electrode assembly 130 includes a first negative electrode 1301, a second negative electrode 1302, a first positive electrode 1303, a second positive electrode 1304, and multiple separators 1305. The first negative electrode 1301, the first positive electrode 1303, the second negative electrode 1302, and the second positive electrode 1304 are alternately stacked, and the first negative electrode 1301 and the first positive electrode 1304 are... The positive electrode plates 1303 are separated by a separator 1305, the first positive electrode plate 1303 and the second negative electrode plate 1302 are separated by another separator 1305, and the second negative electrode plate 1302 and the second positive electrode plate 1304 are separated by another separator 1305. All the first negative electrode plates 1301, the second negative electrode plates 1302, the first positive electrode plates 1303, the second positive electrode plates 1304 and the multiple separators 1305 are stacked and wound around the winding axis K to form a flat winding structure.

[0123] In the winding structure of the electrode assembly, all the negative tabs of the first negative electrode 1301 and all the negative tabs of the second negative electrode 1302 can be located in the flat region 10A. For example, all the negative tabs are located in the first sub-flat region 10A1 or all the negative tabs are located in the second sub-flat region 10A2. Alternatively, some of the negative tabs are located in the first sub-flat region 10A1 and another part of the negative tabs are located in the second sub-flat region 10A2. However, the negative tabs located in the same region at least partially overlap in the direction perpendicular to the winding axis, for example, substantially overlap.

[0124] All positive tabs of the first positive electrode 1303 and all positive tabs of the second positive electrode 1304 can be located in the flat region 10A. For example, all positive tabs can be located in the first sub-flat region 10A1 or all positive tabs can be located in the second sub-flat region 10A2. Alternatively, some positive tabs can be located in the first sub-flat region 10A1 and another part of the positive tabs can be located in the second sub-flat region 10A2. However, positive tabs located in the same region at least partially overlap in the direction perpendicular to the winding axis, for example, substantially overlap. The structure of the electrode assembly 130 in this embodiment is similar to... Figure 9 The electrode assemblies described in the embodiments have basically similar structures, with the differences being as follows.

[0125] In the winding structure of the electrode assembly 130 in this embodiment, the innermost ring of the winding structure is the ring surrounded by the first negative electrode 1301, and the outermost ring of the winding structure is the ring jointly surrounded by the first negative electrode 1301 and the second negative electrode 1302.

[0126] The first winding end E of the first positive electrode 1303 and the second positive electrode 1304 are at different positions. For example, the first winding end E of the first positive electrode 1303 and the second positive electrode 1304 are located in the second turning region 10B2 and the first turning region 10B1, respectively.

[0127] The positions of the second winding ends E' of the first negative electrode 1301 and the second negative electrode 1302 are also different. For example, the second winding ends E' of the first negative electrode 1301 and the second negative electrode 1302 are located in the first turning area 10B1 and the second turning area 10B2, respectively.

[0128] Along the winding direction, the second winding end E' of the first negative electrode 1301 extends beyond the first winding end E of the second positive electrode 1304, and the second winding end E' of the second negative electrode 1302 extends beyond the first winding end E of the first positive electrode 1303.

[0129] The winding structure of the electrode assembly described above can reduce the step formed by the first positive electrode 1303 and the second positive electrode 1304 at the first winding end E, and reduce the step formed by the first negative electrode 1301 and the second negative electrode 1302 at the second winding end E'. This reduces the local stress on the electrode at the winding end after the electrode assembly contacts the housing when it expands, preventing the electrode from breaking or the active material from falling off, and improving the reliability of the electrode assembly during long-term operation.

[0130] like Figure 11 The diagram shows a cross-section of a flat electrode assembly perpendicular to the winding axis K, according to another embodiment of this disclosure. The electrode assembly 140 includes a first negative electrode 1401, a second negative electrode 1402, a first positive electrode 1403, a second positive electrode 1404, and multiple separators 1405. The first negative electrode 1401, the first positive electrode 1403, the second negative electrode 1402, and the second positive electrode 1404 are alternately stacked, and the first negative electrode 1401 and the first positive electrode 1405 are... The positive electrode plates 1403 are separated by a separator 1405, the first positive electrode plate 1403 and the second negative electrode plate 1402 are separated by another separator 1405, and the second negative electrode plate 1402 and the second positive electrode plate 1404 are separated by another separator 1405. All the first negative electrode plates 1401, the second negative electrode plates 1402, the first positive electrode plates 1403, the second positive electrode plates 1404 and the multiple separators 1405 are stacked and wound around the winding axis K to form a flat winding structure.

[0131] In the winding structure of the electrode assembly, all the negative electrode tabs of the first negative electrode 1401 and all the negative electrode tabs of the second negative electrode 1402 can be located in the flat region 10A. For example, all the negative electrode tabs are located in the first sub-flat region 10A1 or all the negative electrode tabs are located in the second sub-flat region 10A2. Alternatively, some of the negative electrode tabs are located in the first sub-flat region 10A1 and another part of the negative electrode tabs are located in the second sub-flat region 10A2. However, the negative electrode tabs located in the same region at least partially overlap in the direction perpendicular to the winding axis, for example, substantially overlap.

[0132] All positive tabs of the first positive electrode 1403 and all positive tabs of the second positive electrode 1404 can be located in the flat region 10A. For example, all positive tabs may be located in the first sub-flat region 10A1 or all positive tabs may be located in the second sub-flat region 10A2. Alternatively, some positive tabs may be located in the first sub-flat region 10A1 and another part of the positive tabs may be located in the second sub-flat region 10A2. However, positive tabs located in the same region may at least partially overlap in the direction perpendicular to the winding axis, for example, substantially overlap.

[0133] The structure of the electrode assembly 140 in this embodiment is similar to... Figure 9The electrode assembly 10 described in the embodiments has a basically similar structure, with the differences being as follows.

[0134] In the winding structure of the electrode assembly 140 in this embodiment, the innermost ring of the winding structure is the ring surrounded by the first negative electrode 1401, and the outermost ring of the winding structure is the ring surrounded by the second negative electrode 1402.

[0135] In the winding structure of the electrode assembly in this embodiment, the second winding ends E' of the first negative electrode 1401 and the second negative electrode 1402 are not in the same position. For example, the second winding ends E' of the first negative electrode 1401 and the second negative electrode 1402 are both located in the same turning area (e.g., the first turning area 10B1), and the second winding ends E' of the first negative electrode 1401 and the second negative electrode 1402 are not aligned.

[0136] The winding structure of the electrode assembly 140 described above can reduce the difference in the number of electrode layers between the first sub-flat region 14A1 and the second sub-flat region 14A2. When the electrode assembly expands and comes into contact with the housing, the inner wall of the housing applies a reaction force to the two planes of the electrode assembly, which can make the stress on the electrode sheets of the first sub-flat region 14A1 and the second sub-flat region 14A2 more consistent.

[0137] like Figure 12 The diagram shows a cross-sectional view of a flat electrode assembly perpendicular to the winding axis K, according to another embodiment of this disclosure. The electrode assembly 150 includes a first negative electrode 1501, a second negative electrode 1502, a first positive electrode 1503, a second positive electrode 1504, and multiple separators 1505. The first negative electrode 1501, the first positive electrode 1503, the second negative electrode 1502, and the second positive electrode 1504 are alternately stacked, and the first negative electrode 1501 and the first positive electrode 1504 are... The positive electrode 1503 is separated by a separator 1505, the first positive electrode 1503 and the second negative electrode 1502 are separated by another separator 1505, the second negative electrode 1502 and the second positive electrode 1504 are separated by another separator 1505, and all the first negative electrode 1501, the second negative electrode 1502, the first positive electrode 1503, the second positive electrode 1504 and the multiple separators 1505 are stacked and wound around the winding axis K to form a flat winding structure.

[0138] In the winding structure of the electrode assembly, all the negative tabs of the first negative electrode 1501 and all the negative tabs of the second negative electrode 1502 can be located in the flat region 10A. For example, all the negative tabs are located in the first sub-flat region 10A1 or all the negative tabs are located in the second sub-flat region 10A2. Alternatively, some of the negative tabs are located in the first sub-flat region 10A1 and another part of the negative tabs are located in the second sub-flat region 10A2. However, the negative tabs located in the same region at least partially overlap in the direction perpendicular to the winding axis, for example, substantially overlap.

[0139] All positive tabs of the first positive electrode 1503 and all positive tabs of the second positive electrode 1504 can be located in the flat region 10A. For example, all positive tabs may be located in the first sub-flat region 10A1 or all positive tabs may be located in the second sub-flat region 10A2. Alternatively, some positive tabs may be located in the first sub-flat region 10A1 and another part of the positive tabs may be located in the second sub-flat region 10A2. However, positive tabs located in the same region may at least partially overlap in the direction perpendicular to the winding axis, for example, substantially overlap.

[0140] The structure of the electrode assembly 10 in this embodiment is similar to... Figure 9 The structure of the electrode assembly 10 described in the embodiment is basically similar, with the following differences. In the winding structure of the electrode assembly in this embodiment, the innermost ring of the winding structure is the ring jointly surrounded by the first negative electrode 1501 and the second negative electrode 1502, and the outermost ring of the winding structure is the ring surrounded by the second negative electrode 1502.

[0141] In the winding structure of the electrode assembly 150 in this embodiment, the first winding start ends S of the first positive electrode 1503 and the second positive electrode 1504 are at different positions. For example, the first winding start ends S of the first positive electrode 1503 and the second positive electrode 1504 are located in the first sub-flat region 10A1 and the second sub-flat region 10A2, respectively, and the first winding start ends S of the first positive electrode 1503 and the second positive electrode 1504 are not flush.

[0142] The positions of the second winding start ends S of the first negative electrode 1501 and the second negative electrode 1502 are also different. For example, the second winding start ends S of the first negative electrode 1501 and the second negative electrode 1502 are located in the first sub-straight region 10A1 and the second sub-straight region 10A2, respectively, and the second winding start ends S of the first negative electrode 1501 and the second negative electrode 1502 are not aligned.

[0143] The winding structure of the electrode assembly described above can reduce the step formed by the first positive electrode 1503 and the second positive electrode 1504 at the first winding start end S, and reduce the step formed by the first negative electrode 1501 and the second negative electrode 1502 at the second winding start end S'. This reduces the local stress at the winding start end after the electrode assembly contacts the housing 20 when it expands, preventing the electrode from breaking or the active material from falling off, and improving the reliability of the electrode assembly during long-term operation.

[0144] like Figure 13 The diagram shows a cross-sectional view of a flat electrode assembly perpendicular to the winding axis K, according to another embodiment of this disclosure. The electrode assembly 160 includes a first negative electrode 1601, a second negative electrode 1602, a first positive electrode 1603, a second positive electrode 1604, and multiple separators 1605. The first negative electrode 1601, the first positive electrode 1603, the second negative electrode 1602, and the second positive electrode 1604 are alternately stacked, and the first negative electrode 1601 and the first positive electrode 1604 are... The positive electrode plates 1603 are separated by a separator 1605, the first positive electrode plate 1603 and the second negative electrode plate 1602 are separated by another separator 1605, and the second negative electrode plate 1602 and the second positive electrode plate 1604 are separated by another separator 1605. All the first negative electrode plates 1601, the second negative electrode plates 1602, the first positive electrode plates 1603, the second positive electrode plates 1604 and the multiple separators 1605 are stacked and wound around the winding axis K to form a flat winding structure.

[0145] In the winding structure of the electrode assembly, all the negative tabs of the first negative electrode 1601 and all the negative tabs of the second negative electrode 1602 can be located in the flat region 10A. For example, all the negative tabs are located in the first sub-flat region 10A1 or all the negative tabs are located in the second sub-flat region 10A2. Alternatively, some of the negative tabs are located in the first sub-flat region 10A1 and another part of the negative tabs are located in the second sub-flat region 10A2. However, the negative tabs located in the same region at least partially overlap in the direction perpendicular to the winding axis, for example, substantially overlap.

[0146] All positive tabs of the first positive electrode 1603 and all positive tabs of the second positive electrode 1604 can be located in the flat region 10A. For example, all positive tabs may be located in the first sub-flat region 10A1 or all positive tabs may be located in the second sub-flat region 10A2. Alternatively, some positive tabs may be located in the first sub-flat region 10A1 and another part of the positive tabs may be located in the second sub-flat region 10A2. However, positive tabs located in the same region may at least partially overlap in the direction perpendicular to the winding axis, for example, substantially overlap.

[0147] The structure of the electrode assembly 160 in this embodiment is similar to... Figure 9The electrode assembly 10 described in the embodiments has a basically similar structure, with the differences as follows. In the winding structure of the electrode assembly 10 in this embodiment, the innermost ring of the winding structure is the ring jointly surrounded by the first negative electrode 1601 and the second negative electrode 1602, and the outermost ring of the winding structure is the ring jointly surrounded by the first negative electrode 1601 and the second negative electrode 1602.

[0148] In the winding structure of the electrode assembly 160 in this embodiment, the first winding start ends S of the first positive electrode 1603 and the second positive electrode 1604 are at different positions. For example, the first winding start ends S of the first positive electrode 1603 and the second positive electrode 1604 are located in the first sub-flat region 10A1 and the second sub-flat region 10A2, respectively, and the first winding start ends S of the first positive electrode 1603 and the second positive electrode 1604 are not flush.

[0149] The positions of the second winding start ends S' of the first negative electrode 1601 and the second negative electrode 1602 are also different. For example, the second winding start ends S' of the first negative electrode 1601 and the second negative electrode 1602 are located in the first sub-straight region 10A1 and the second sub-straight region 10A2, respectively, and the second winding start ends S' of the first negative electrode 1601 and the second negative electrode 1602 are not aligned.

[0150] The first winding ends E of the first positive electrode 1603 and the second positive electrode 1604 are at different positions. For example, the first winding ends E of the first positive electrode 1603 and the second positive electrode 1604 are located in different turning areas 10B. Furthermore, the first winding ends E of the first positive electrode 1303 and the second positive electrode 1304 are not aligned.

[0151] The positions of the second winding ends E' of the first negative electrode 1601 and the second negative electrode 1602 are also different. For example, the second winding ends E' of the first negative electrode 1601 and the second negative electrode 1602 are located in two different turning areas 10B. Furthermore, the second winding ends E' of the first negative electrode 1601 and the second negative electrode 1602 are not aligned.

[0152] The winding structure of the electrode assembly described above can simultaneously reduce the steps formed by the first positive electrode 1603 and the second positive electrode 1604 at the first winding start S and the first winding end E, and reduce the steps formed by the first negative electrode 1601 and the second negative electrode 1602 at the second winding start S' and the second winding end E'. This reduces the local stress on the electrode assembly at the winding start and winding end after it comes into contact with the housing 20 when it expands, preventing the electrode from breaking or the active material from falling off, and improving the reliability of the electrode assembly during long-term operation.

[0153] Based on the above embodiments, the number of electrode layers does not differ by a preset number in different radial directions of the winding structure, i.e., at different positions circumferentially around the winding structure. Here, the number of electrode layers refers to the total number of positive and negative electrode layers. The preset number of layers is less than or equal to the sum of the number of positive and negative electrode sheets.

[0154] When the electrode assembly expands and comes into contact with the housing 20, the housing 20 applies a reaction force to the electrode assembly, which makes the force on the electrode assembly more uniform in all directions and prevents large performance differences in different parts of the electrode assembly during use. For example, two positive electrode sheets and two layers of negative electrode sheets are set, with a preset number of layers less than or equal to four. The smaller the difference in the number of electrode sheets, the more uniform the force on the electrode assembly in all directions.

[0155] Figures 14 to 17 A schematic diagram of the cylindrical electrode assembly is shown.

[0156] like Figure 14 The diagram shows a cross-section of a cylindrical electrode assembly perpendicular to the winding axis K, according to another embodiment of this disclosure. The electrode assembly 170 includes a first negative electrode 1701, a second negative electrode 1702, a first positive electrode 1703, a second positive electrode 1704, and multiple separators 1705. The first negative electrode 1701, the first positive electrode 1703, the second negative electrode 1702, and the second positive electrode 1704 are alternately stacked, and the first negative electrode 1701 and the first positive electrode 1704 are... The positive electrode plates 1703 are separated by a separator 1705, the first positive electrode plate 1703 and the second negative electrode plate 1702 are separated by another separator 1705, and the second negative electrode plate 1702 and the second positive electrode plate 1704 are separated by another separator 1705. All the first negative electrode plates 1701, the second negative electrode plates 1702, the first positive electrode plates 1703, the second positive electrode plates 1704 and the multiple separators 1705 are stacked and wound around the winding axis K to form a cylindrical winding structure.

[0157] In this embodiment, the structure and position of the tabs on both the positive and negative electrodes can be referenced from the previous description. Figure 5-8 The relevant details described in the embodiments regarding the first electrode tab of the first electrode and the second electrode tab of the second electrode are not repeated here.

[0158] In the winding structure, the innermost ring is the ring surrounded by the first negative electrode 1701, and the outermost ring is the ring surrounded by the second negative electrode 1702.

[0159] The first winding start end S of the first positive electrode 1703 and the second positive electrode 1704 are in the same position. For example, the first winding start end S of the first positive electrode 1703 and the second positive electrode 1704 are both located on the same radial direction of the winding structure, and the first winding start end S of the first positive electrode 1703 and the second positive electrode 1704 are flush.

[0160] The second winding start point S' of the first negative electrode 1701 and the second negative electrode 1702 are also in the same position. For example, the second winding start point S' of the first negative electrode 1701 and the second negative electrode 1702 are both located on the same radial direction of the winding structure, and the second winding start point S' of the first negative electrode 1701 and the second negative electrode 1702 are flush.

[0161] In the opposite direction of the winding direction, the second winding start S' of the first negative electrode 1701 extends beyond the first winding start S of the first positive electrode 1704. The second winding start S' of the second negative electrode 1702 extends beyond the first winding start S of the second positive electrode 1703.

[0162] The first winding ends E of the first positive electrode 1703 and the second positive electrode 1704 are at the same position. For example, the first winding ends E of the first positive electrode 1703 and the second positive electrode 1704 are both located in the turning area 10B on the same side, and the first winding ends E of the first positive electrode 1703 and the second positive electrode 1704 are flush.

[0163] The second winding ends E' of the first negative electrode 1701 and the second negative electrode 1702 are also in the same position. For example, the second winding ends E' of the first negative electrode 1701 and the second negative electrode 1702 are both located in the same turning area 10B, and the second winding ends E' of the first negative electrode 1701 and the second negative electrode 1702 are flush.

[0164] Along the winding direction, the second winding end E' of the first negative electrode 1701 extends beyond the first winding end E of the second positive electrode 1704, and the second winding end E' of the second negative electrode 1702 extends beyond the first winding end E of the first positive electrode 1703.

[0165] The winding structure described above enables the length differences of multiple electrodes to be close before winding, making winding easier.

[0166] like Figure 15The diagram shows a cross-section of a cylindrical electrode assembly perpendicular to the winding axis K, according to another embodiment of this disclosure. The electrode assembly 180 includes a first negative electrode 1801, a second negative electrode 1802, a first positive electrode 1803, a second positive electrode 1804, and multiple separators 1805. The first negative electrode 1801, the first positive electrode 1803, the second negative electrode 1802, and the second positive electrode 1804 are alternately stacked, and the first negative electrode 1801 and the first positive electrode 1804 are... The positive electrode plates 1803 are separated by a separator 1805, the first positive electrode plate 1803 and the second negative electrode plate 1802 are separated by another separator 1805, and the second negative electrode plate 1802 and the second positive electrode plate 1804 are separated by another separator 1805. All the first negative electrode plates 1801, the second negative electrode plates 1802, the first positive electrode plates 1803, the second positive electrode plates 1804 and the multiple separators 1805 are stacked and wound around the winding axis K to form a cylindrical winding structure.

[0167] The structure of the electrode assembly 10 in this embodiment is similar to... Figure 14 The electrode assembly 10 described in the embodiments has a basically similar structure, with the differences as follows. In the winding structure of this embodiment, the innermost ring of the winding structure is the ring jointly surrounded by the first negative electrode 1801 and the second negative electrode 1802, and the outermost ring of the winding structure is the ring surrounded by the first negative electrode 1801.

[0168] In the winding structure of this embodiment, the first winding start ends S of the first positive electrode 1803 and the second positive electrode 1804 are at different positions. For example, the first winding start ends S of the first positive electrode 1803 and the second positive electrode 1804 are located on the opposite radial side of the winding structure, and the first winding start ends S of the first positive electrode 1803 and the second positive electrode 1804 are not aligned.

[0169] The positions of the second winding start ends S of the first negative electrode 1801 and the second negative electrode 1802 are also different. For example, the second winding start ends S' of the first negative electrode 1801 and the second winding start ends S' of the second negative electrode 1802 are located on the opposite radial side of the winding structure, and the second winding start ends S' of the first negative electrode 1801 and the second negative electrode 1802 are not aligned.

[0170] The winding structure described above can reduce the steps formed by the first positive electrode 1803 and the second positive electrode 1804 at the first winding start end S, and reduce the steps formed by the first negative electrode 1801 and the second negative electrode 1802 at the second winding start end S'. This reduces the local stress at the winding start end after contact with the shell 20 during expansion, preventing electrode breakage or active material shedding, and improving the reliability of long-term operation.

[0171] like Figure 16The diagram shows a cross-section of a cylindrical electrode assembly perpendicular to the winding axis K, according to another embodiment of this disclosure. The electrode assembly 190 includes a first negative electrode 1901, a second negative electrode 1902, a first positive electrode 1903, a second positive electrode 1904, and multiple separators 1905. The first negative electrode 1901, the first positive electrode 1903, the second negative electrode 1902, and the second positive electrode 1904 are alternately stacked, and the first negative electrode 1901 and the first positive electrode 1904 are stacked in sequence. The electrodes 1903 are separated by a diaphragm 1905, the first positive electrode 1903 and the second negative electrode 1902 are separated by another diaphragm 1905, and the second negative electrode 1902 and the second positive electrode 1904 are separated by another diaphragm 1905. All the first negative electrode 1901, the second negative electrode 1902, the first positive electrode 1903, the second positive electrode 1904 and the multiple diaphragms 1905 are stacked and wound around the winding axis K to form a flat winding structure.

[0172] The structure described in this embodiment and Figure 15 The structures described in the embodiments are basically similar, with the differences as follows. In the winding structure of this embodiment, the innermost ring of the winding structure is the ring jointly surrounded by the first negative electrode 1901 and the second negative electrode 1902, and the outermost ring of the winding structure is the ring surrounded by the first negative electrode 1901.

[0173] In the winding structure of this embodiment, the first winding end E of the first positive electrode 1903 and the second positive electrode 1904 are at different positions, and the second winding end E' of the first negative electrode 1901 and the second negative electrode 1902 are also at different positions.

[0174] Along the winding direction, the first negative electrode 1901 is located on the outermost layer, and the end position of the second winding end E' extends beyond the end position of the second winding end E' of the second negative electrode 1902. The end position of the second winding end E' of the first positive electrode 1903 extends beyond the end position of the second winding end E' of the second positive electrode 1904. For example, it extends beyond half a turn, and the excess portion is pressed radially inward to contact the inner electrode to improve the stability of the winding structure.

[0175] The winding structure described above can simultaneously reduce the steps formed by the first positive electrode 1903 and the second positive electrode 1904 at the first winding start S and the first winding end E, and reduce the steps formed by the first negative electrode 1901 and the second negative electrode 1902 at the second winding start S' and the second winding end E'. This reduces the local stress at the winding start and winding end after contact with the shell 20 during expansion, preventing electrode breakage or active material shedding and improving long-term operational reliability.

[0176] Moreover, this method can achieve the same number of layers in different radial directions. For cylindrical winding structures, it can make the stress along the circumference more consistent when expansion occurs and the structure comes into contact with the shell 20.

[0177] like Figure 17 The diagram shows a cross-section of a cylindrical electrode assembly perpendicular to the winding axis K, according to another embodiment of this disclosure. The electrode assembly 200 includes a first negative electrode 2001, a second negative electrode 2002, a first positive electrode 2003, a second positive electrode 2004, and multiple separators 2005. The first negative electrode 2001, the first positive electrode 2003, the second negative electrode 2002, and the second positive electrode 2004 are alternately stacked, and the first negative electrode 2001 and the first positive electrode 2004 are interleaved. The electrodes 2003 are separated by a separator 2005, the first positive electrode 2003 and the second negative electrode 2002 are separated by another separator 2005, and the second negative electrode 2002 and the second positive electrode 2004 are separated by another separator 2005. All the first negative electrode 2001, the second negative electrode 2002, the first positive electrode 2003, the second positive electrode 2004 and the multiple separators 2005 are stacked and wound around the winding axis K to form a flat winding structure.

[0178] The structure of the electrode assembly 10 in this embodiment is similar to... Figure 15 The electrode assembly 10 described in the embodiments has a basically similar structure, with the differences as follows. In the winding structure of this embodiment, the innermost ring of the winding structure is the ring jointly surrounded by the first negative electrode 2001 and the second negative electrode 2002, and the outermost ring of the winding structure is the ring jointly surrounded by the first negative electrode 2001 and the second negative electrode 2002.

[0179] Along the winding direction, the second negative electrode 2002 is located on the outermost layer, and the end position of the second winding end E' exceeds the end position of the second winding end E' of the first negative electrode 2001. The end position of the second winding end E' of the second positive electrode 2004 exceeds the end position of the second winding end E' of the first positive electrode 2003. For example, it exceeds half a turn.

[0180] The winding structure described above can simultaneously reduce the steps formed by the first positive electrode 2003 and the second positive electrode 2004 at the first winding start S and the first winding end E, and reduce the steps formed by the first negative electrode 2001 and the second negative electrode 2002 at the second winding start S' and the second winding end E'. This reduces the local stress at the winding start and winding end after contact with the shell 20 during expansion, preventing electrode breakage or active material shedding and improving long-term operational reliability.

[0181] Moreover, this method can achieve the same number of layers in different radial directions. For cylindrical winding structures, it can make the stress along the circumference more consistent when expansion occurs and the structure comes into contact with the shell 20.

[0182] In addition, this structure can prevent the outermost and penultimate electrode layers from bending at the winding ends of other electrode layers, ensuring reliable contact between the electrode layers and preventing localized stress on the electrode, thereby preventing electrode breakage or loss of active material.

[0183] Secondly, this disclosure also provides a method for manufacturing an electrode assembly, in some embodiments, such as... Figure 18 The flowchart shown includes:

[0184] Step 101: Provide multiple first electrode plates 1 and at least one second electrode plate 2, wherein the first electrode plates 1 and the second electrode plate 2 have opposite polarities;

[0185] Step 102: Wind multiple first electrode plates 1 and at least one second electrode plate 2 around the winding axis K to form a winding structure;

[0186] In the winding structure, the first electrode 1 of multiple first electrode plates 1 and the second electrode 2 of at least one second electrode plate 2 are alternately arranged in a direction perpendicular to the winding axis K; each first electrode plate 1 includes a first current collector 11 and a first active material layer 12 disposed on the superimposed surface of the first current collector 11. The first current collector includes a first main body portion 111 disposed with the first active material layer 12 and a first electrode tab 112 protruding from the first main body portion 111 along the winding axis direction, and the first electrode tab 112 and the first main body portion 111 are distributed side by side along the winding axis.

[0187] In this embodiment, by setting multiple first electrode plates 1, the number of winding turns of the electrode assembly 10 can be reduced, which can reduce the misalignment of the first electrode tab 112 in the circumferential direction after winding, and make it easier to connect with the current collector 30.

[0188] Finally, this disclosure also provides an electrode assembly manufacturing apparatus 500, in some embodiments, such as Figure 19 As shown, it includes:

[0189] The electrode placement mechanism 501 is configured to provide multiple first electrodes 1 and at least one second electrode 2, wherein the polarities of the first electrodes 1 and the second electrodes 2 are opposite; and

[0190] The winding mechanism 502 is configured to wind multiple first electrode sheets 1 and at least one second electrode sheet 2 around a winding axis K to form a winding structure. In the winding structure, the first electrode sheets 1 of the multiple first electrode sheets 1 and the second electrode sheets 2 of the at least one second electrode sheet 2 are alternately arranged in a direction perpendicular to the winding axis K. Each first electrode sheet 1 includes a first current collector 11 and a first active material layer 12 disposed on the stacking surface of the first current collector 11. The first current collector 11 includes a first main body portion 111 on which the first active material layer 12 is disposed and a first electrode tab 112 protruding from the first main body portion 111 along the winding axis direction. The first electrode tab 112 and the first main body portion 111 are distributed side-by-side along the winding axis. The winding mechanism 502 can provide stable winding tension for the stacked electrode sheets.

[0191] The electrode assembly 10 manufactured by the electrode assembly manufacturing apparatus 500 can reduce winding errors during the winding process.

[0192] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure and not to limit them; although this disclosure has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this disclosure or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of this disclosure, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in this disclosure.

Claims

1. An electrode assembly, characterized in that, It includes multiple first electrode plates and at least one second electrode plate, the first electrode plates and the second electrode plate having opposite polarities. The multiple first electrode plates and the at least one second electrode plate are wound around a winding axis to form a winding structure. The winding structure is flat and includes a straight area and a turning area located on both sides of the straight area. In the winding structure, the multiple first electrode plates and the at least one second electrode plate are stacked in a direction perpendicular to the winding axis. Each of the multiple first electrode sheets includes a first current collector and a first active material layer disposed on the superimposed surface of the first current collector. The first current collector includes a first main body portion disposed of the first active material layer and at least one first electrode tab protruding from the first main body portion along the winding axis direction. In this configuration, each of the at least one first electrode tabs and the first main body portion are arranged side by side along the winding axis. At least two of the multiple first electrode pieces have different winding start positions, at least two of the multiple first electrode pieces have different winding end positions, and at least one of the multiple first electrode pieces has its winding end located in the turning area.

2. The electrode assembly according to claim 1, characterized in that, Each first electrode includes a plurality of first electrode tabs spaced apart.

3. The electrode assembly according to claim 1, characterized in that, In the winding structure, each first electrode sheet has at least one tab on each of its turns.

4. The electrode assembly according to claim 1, characterized in that, Any two of the first electrodes at least partially overlap.

5. The electrode assembly according to claim 1, characterized in that, All of the first tabs are located in the flat region.

6. The electrode assembly according to claim 5, characterized in that, The straight region includes a first sub-straight region and a second sub-straight region that are substantially parallel and symmetrically distributed about the winding axis. All first electrodes are located in either the first sub-flat region or the second sub-flat region; or Of all the first tabs, a portion is located in the first sub-flat region and the other portion is located in the second sub-flat region.

7. The electrode assembly according to claim 1, characterized in that, The electrode assembly includes multiple second electrode sheets, wherein at least two of the multiple second electrode sheets have different winding start positions; and / or at least two of the multiple second electrode sheets have different winding end positions.

8. The electrode assembly according to claim 1, characterized in that, The electrode assembly includes multiple second electrode plates, and the winding structure is flat, including a straight region and a turning region located on both sides of the straight region; Wherein, the winding end of at least one of the multiple second electrode sheets is located in the turning area.

9. The electrode assembly according to any one of claims 1 to 8, characterized in that, In different radial directions of the winding structure, the number of layers of the first electrode and the second electrode does not differ by more than a preset number of layers.

10. The electrode assembly according to claim 9, characterized in that, The preset number of layers is less than or equal to the sum of the number of all first electrodes and all second electrodes.

11. A battery, characterized in that, include: case; and The electrode assembly as claimed in any one of claims 1 to 10, wherein the electrode assembly is disposed within the housing.

12. A battery module, characterized in that, include: Multiple batteries as described in claim 11.

13. A battery pack, characterized in that, include: Multiple battery modules as described in claim 12.

14. A device using a battery, characterized in that, include: The battery of claim 11, wherein the battery is used to provide electrical energy.

15. A method for manufacturing an electrode assembly, characterized in that, include: Provide multiple first electrodes and at least one second electrode, wherein the first electrodes and the second electrodes have opposite polarities; The plurality of first electrode plates and the at least one second electrode plate are wound around a winding axis to form a winding structure. The winding structure is flat and includes a straight area and a turning area located on both sides of the straight area. In the winding structure, the first electrode sheets of the plurality of first electrode sheets and the second electrode sheets of the at least one second electrode sheet are stacked in a direction perpendicular to the winding axis. Each first electrode sheet includes a first current collector and a first active material layer disposed on the stacking surface of the first current collector. The first current collector includes a first main body portion disposed of the first active material layer and at least one first electrode tab protruding from the first main body portion along the winding axis. Each of the at least one first electrode tab and the first main body portion are distributed side by side along the winding axis. The winding start positions of at least two of the plurality of first electrode sheets are different, the winding end positions of at least two of the plurality of first electrode sheets are different, and the winding end of at least one of the plurality of first electrode sheets is located in the turning area.

16. An apparatus for manufacturing an electrode assembly, characterized in that, include: An electrode placement mechanism is configured to provide a plurality of first electrodes and at least one second electrode, wherein the first electrodes and the second electrodes have opposite polarities. and A winding mechanism is configured to wind a plurality of first electrode sheets and at least one second electrode sheet around a winding axis to form a winding structure. The winding structure is flat and includes a straight region and a turning region located on both sides of the straight region. In the winding structure, the first electrode sheets of the plurality of first electrode sheets and the second electrode sheets of the at least one second electrode sheet are stacked in a direction perpendicular to the winding axis. Each first electrode sheet includes a first current collector and a first active material layer disposed on the stacking surface of the first current collector. The first current collector includes a first main body portion disposed of the first active material layer and at least one first electrode tab protruding from the first main body portion along the winding axis. Each of the at least one first electrode tab and the first main body portion are distributed side by side along the winding axis. The winding start positions of at least two of the plurality of first electrode sheets are different, the winding end positions of at least two of the plurality of first electrode sheets are different, and the winding end of at least one of the plurality of first electrode sheets is located in the turning region.

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