Electrode assembly and method of manufacturing the same, battery cell, battery, and electric device

Abstract

The application provides an electrode assembly and a manufacturing method thereof, a battery monomer, a battery and an electric device, and belongs to the technical field of batteries. The electrode assembly comprises a negative electrode sheet and a positive electrode sheet. The negative electrode sheet and the positive electrode sheet are wound along a winding direction to form the electrode assembly. The electrode assembly has a flat area and a bending area. The negative electrode sheet comprises a plurality of flat parts which are arranged in layers in the flat area. The positive electrode sheet comprises a first section and a second section which are arranged in layers and in sequence along the winding direction. The first section is located in the flat area and arranged in layers between two adjacent flat parts. The second section is arranged in layers with the negative electrode sheet and continuously wound along the winding direction. In the opposite direction of the winding direction, the second section and the adjacent first section form a first non-electrode sheet area. At least part of the first non-electrode sheet area is located in the bending area. This structure can relieve the phenomenon that the inner ring of the positive electrode sheet has a large bending degree and generates a large tension, thereby reducing the risk of lithium precipitation or fracture of the positive electrode sheet during use.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to an electrode assembly and its manufacturing method, a battery cell, a battery, and an electrical device. Background Technology

[0002] In recent years, new energy vehicles have experienced rapid development. In the field of electric vehicles, power batteries, as the power source, play an irreplaceable and crucial role. With the vigorous promotion of new energy vehicles, the demand for power battery products is also increasing. Among them, batteries, as core components of new energy vehicles, have high requirements in terms of both service life and safety. A battery cell is assembled into an electrode assembly (bare cell) by winding or stacking positive electrode sheets, negative electrode sheets, and a separator, then installed in a casing, and finally injected with electrolyte. Among them, the wound electrode assembly has the advantages of easy assembly, low manufacturing difficulty, and high production efficiency, thus it has been widely used. However, the inner ring of the existing wound electrode assembly has a large bending radius at the corners, which often leads to risks such as lithium plating or breakage during use, resulting in poor performance of the battery cell and significant safety hazards. Summary of the Invention

[0003] This application provides an electrode assembly and its manufacturing method, a battery cell, a battery, and an electrical device, which can effectively improve the performance and safety of the battery cell.

[0004] In a first aspect, embodiments of this application provide an electrode assembly, including a negative electrode and a positive electrode, wherein the negative electrode and the positive electrode are wound along a winding direction to form the electrode assembly, the electrode assembly having a flat region and a bent region connected to the flat region, the negative electrode being continuous in the winding direction, and the negative electrode including a plurality of flat portions stacked in the flat region; wherein the positive electrode includes a first segment and a second segment spaced apart and sequentially arranged along the winding direction, the first segment being located in the flat region and stacked between two adjacent flat portions, the second segment being stacked with the negative electrode and continuously wound along the winding direction, and in the opposite direction to the winding direction, a first non-electrode region is formed between the second segment and the adjacent first segment, at least a portion of the first non-electrode region being located in the bent region.

[0005] In the above technical solution, the electrode assembly is a wound structure formed by winding a negative electrode sheet and a positive electrode sheet together along the winding direction. The negative electrode sheet is continuously arranged along the winding direction, and the positive electrode sheet has a first segment and a second segment arranged at intervals and sequentially along the winding direction. By placing the first segment entirely within a flat region, continuously winding the second segment and the negative electrode sheet along the winding direction, and placing at least a portion of the first non-electrode area formed between the second segment and the adjacent first segment within a bending region of the electrode assembly, the inner ring of the electrode assembly forms a structure in which the flat portion of the negative electrode sheet and the first segment of the positive electrode sheet are stacked together, and the outer ring of the electrode assembly forms a structure in which the negative electrode sheet and the second segment of the positive electrode sheet are wound together. This electrode assembly structure can alleviate the bending stress on the inner ring of the positive electrode sheet. The greater bending degree in the bending zone generates greater tension, effectively reducing the risk of lithium plating or breakage of the inner ring of the positive electrode sheet located within the bending zone during use, thus puncturing the separator. This improves the performance and safety of the electrode assembly. Furthermore, it eliminates the need to construct the entire positive electrode sheet as multiple first segments wound with the negative electrode sheet. Instead, the inner ring of the electrode assembly can be constructed by stacking the straight portion of the negative electrode sheet with the first segment of the positive electrode sheet. This effectively ensures the energy density requirements of the electrode assembly and reduces the positional accuracy requirements between the positive and negative electrode sheets, thereby lowering the manufacturing difficulty of the electrode assembly. This significantly optimizes the production cycle time of the electrode assembly, improving production efficiency and meeting capacity demands.

[0006] In some embodiments, the starting end of the second segment is located in the flat region.

[0007] In the above technical solution, by setting the starting end of the winding of the second section and the negative electrode sheet in the flat region, that is, the second section of the positive electrode sheet and the negative electrode sheet are wound from the flat region of the electrode assembly, the bending phenomenon of the starting end of the winding of the second section can be effectively alleviated, thereby reducing the risk of lithium plating or breakage at the starting end of the winding of the second section, which is conducive to improving the performance and safety of the electrode assembly.

[0008] In some embodiments, the positive electrode sheet includes a plurality of first segments; the plurality of first segments are spaced apart along the winding direction, and a second non-electrode region is formed between two adjacent first segments, at least a portion of the second non-electrode region being located in the bending region.

[0009] In the above technical solution, the positive electrode sheet has multiple first segments spaced apart along the winding direction, and the second non-electrode area formed between two adjacent first segments is located in the bending area. That is, the multiple first segments are spaced apart along the winding direction, and the multiple first segments as a whole are spaced apart from the second segments along the winding direction. This makes the inner ring of the electrode assembly form a structure in which multiple first segments and multiple straight portions of the negative electrode sheet are alternately stacked. This can effectively reduce the risk of lithium plating or breakage at multiple bending positions of the inner ring of the positive electrode sheet located in the bending area, which is conducive to further improving the performance and safety of the electrode assembly.

[0010] In some embodiments, the electrode assembly further includes an isolation membrane disposed between the negative electrode and the positive electrode to separate the negative electrode and the positive electrode.

[0011] In the above technical solution, the electrode assembly is also provided with a separator between the negative electrode and the positive electrode, which can effectively separate the negative electrode and the positive electrode to reduce the phenomenon of short circuit between the negative electrode and the positive electrode, thereby helping to reduce the safety hazards of the electrode assembly during use.

[0012] In some embodiments, the first segment is adhered to the release membrane.

[0013] In the above technical solution, by bonding the first section of the positive electrode sheet to the separator, the phenomenon of movement or slippage of the first section during use or manufacturing can be effectively reduced, thereby improving the production quality and performance of the electrode assembly.

[0014] In some embodiments, the first segment is bonded to the release membrane by an adhesive layer located on opposite sides in the length direction of the first segment; and / or the adhesive layer is located on opposite sides in the width direction of the first segment.

[0015] In the above technical solution, by setting the adhesive layer used to bond the first segment and the separator on both sides of the length or width of the first segment, this structure can effectively reduce the impact of the adhesive layer on the coating area on the first segment, thereby ensuring the wetting effect of the electrolyte on the coating area of ​​the first segment.

[0016] In some embodiments, both the first segment and the second segment have a positive electrode tab, and the positive electrode tabs of the first segment and the second segment are stacked along the stacking direction of the plurality of straight portions.

[0017] In the above technical solution, by stacking the first and second electrode tabs along the stacking direction of multiple straight sections, it is easy to connect the first and second electrode tabs to other components, which helps to reduce the manufacturing difficulty of the electrode assembly and realize the electrical energy input or output of the first and second sections of the positive electrode.

[0018] In some embodiments, two adjacent positive electrode tabs are bonded or welded along the stacking direction of the plurality of straight portions.

[0019] In the above technical solution, by bonding or welding two adjacent electrode tabs arranged in layers, the electrode tabs of the first section and the electrode tabs of the second section form an integral structure. This structure facilitates the connection of the electrode tabs of the first section and the electrode tabs of the second section with other components, and also helps to alleviate the phenomenon of movement or slippage of the first section of the positive electrode during use, thereby improving the performance of the electrode assembly.

[0020] Secondly, embodiments of this application also provide a battery cell, including a housing and the aforementioned electrode assembly; the electrode assembly is housed within the housing.

[0021] Thirdly, embodiments of this application also provide a battery comprising a plurality of the aforementioned battery cells.

[0022] Fourthly, embodiments of this application also provide an electrical device, including the battery described above.

[0023] Fifthly, embodiments of this application also provide a method for manufacturing an electrode assembly, comprising: providing a negative electrode sheet and a positive electrode sheet; winding the negative electrode sheet and the positive electrode sheet along a winding direction to form the electrode assembly, the electrode assembly having a flat region and a bent region connected to the flat region, the negative electrode sheet being continuous in the winding direction, the negative electrode sheet including a plurality of flat portions stacked in the flat region; wherein, the positive electrode sheet includes a first segment and a second segment spaced apart and sequentially arranged along the winding direction, the first segment being located in the flat region and stacked between two adjacent flat portions, the second segment being stacked with the negative electrode sheet and continuously wound along the winding direction, and in the opposite direction to the winding direction, a first non-electrode region being formed between the second segment and the adjacent first segment, at least a portion of the first non-electrode region being located in the bent region.

[0024] In the above technical solution, in the electrode assembly formed by winding the negative electrode sheet and the positive electrode sheet, the positive electrode sheet includes a first segment and a second segment arranged at intervals and sequentially along the winding direction. The first segment is entirely disposed in the flat region and stacked between two adjacent flat portions of the stacked negative electrode sheet. The first non-electrode area formed between the second segment and the adjacent first segment is disposed in the bending region of the electrode assembly. This results in the inner ring of the electrode assembly forming a structure in which the flat portion of the negative electrode sheet and the first segment of the positive electrode sheet are stacked together, and the outer ring of the electrode assembly forming a structure in which the negative electrode sheet and the second segment of the positive electrode sheet are wound together. The electrode assembly with this structure can alleviate the phenomenon of large tension caused by the large bending degree of the inner ring of the positive electrode sheet in the bending region. Thus, during the use of the electrode assembly, it can effectively reduce the risk of lithium plating or breakage of the inner ring of the positive electrode sheet located in the bending region, thereby puncturing the separator, and improving the performance and safety of the electrode assembly.

[0025] In some embodiments, winding the negative electrode and the positive electrode along the winding direction includes: providing two separators; winding the negative electrode and the two separators along the winding direction; and during the winding of the negative electrode and the two separators, sequentially placing the first segment and the second segment between the two separators; wherein the separators are disposed between the negative electrode and the positive electrode to separate the negative electrode and the positive electrode.

[0026] In the above technical solution, during the winding of the negative electrode sheet and the positive electrode sheet, the negative electrode sheet is first wound with two separator films. During the winding process, the first and second sections of the positive electrode sheet are sequentially placed between the two separator films, thereby forming an inner ring of the electrode assembly with the straight portion of the negative electrode sheet and the first section of the positive electrode sheet stacked on top of each other, and an outer ring of the electrode assembly with the negative electrode sheet and the second section of the positive electrode sheet wound together. This manufacturing method can eliminate the process of thermally bonding the first and second sections of the positive electrode sheet with the separator film before winding, thereby simplifying the manufacturing process of the electrode assembly, optimizing the production cycle of the electrode assembly, and effectively improving the production efficiency of the electrode assembly to meet the production capacity requirements.

[0027] In some embodiments, before placing the first segment and the second segment sequentially between the two separators during the winding of the negative electrode sheet and the two separators, the method of manufacturing the electrode assembly further includes: providing an adhesive layer on the first segment to adhere the first segment to the separator.

[0028] In the above technical solution, before the first segment of the positive electrode sheet is placed between the two separators, an adhesive layer is provided on the first segment for bonding with the separators. This allows the first segment to bond with the separators when it is placed between the two separators, thereby effectively mitigating the phenomenon of the first segment shifting or slipping during the winding process and improving the production quality of the electrode assembly.

[0029] In some embodiments, both the first segment and the second segment have positive electrode tabs, and the positive electrode tabs of the first segment and the positive electrode tabs of the second segment are stacked along the stacking direction of the plurality of straight portions; after the negative electrode and the positive electrode are wound along the winding direction, the method of manufacturing the electrode assembly further includes: bonding or welding two adjacent positive electrode tabs.

[0030] In the above technical solution, after the negative electrode and positive electrode are wound, multiple tabs stacked along the stacking direction of multiple straight sections are connected together by bonding or welding. The electrode assembly manufactured by this method makes the first and second tabs form an integral structure. This facilitates the connection of the first and second tabs with other components and helps to alleviate the phenomenon of movement or slippage of the first section of the positive electrode during use, thereby improving the performance of the electrode assembly. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0033] Figure 2 Exploded views of the battery structure provided in some embodiments of this application;

[0034] Figure 3 Exploded views of the structure of a single battery cell provided in some embodiments of this application;

[0035] Figure 4 This is a schematic diagram of the structure of an electrode assembly provided in some embodiments of this application;

[0036] Figure 5 A schematic flowchart illustrating a method for manufacturing an electrode assembly according to some embodiments of this application;

[0037] Figure 6 A flowchart illustrating step S200 of a method for manufacturing an electrode assembly according to some embodiments of this application;

[0038] Figure 7 A schematic diagram of the structure of the electrode assembly manufacturing method provided in some embodiments of this application, showing the winding of the negative electrode sheet and two separators;

[0039] Figure 8 A front view of a method for manufacturing an electrode assembly provided in some embodiments of this application, showing the winding of a negative electrode sheet and two separator films;

[0040] Figure 9 A schematic diagram of the structure in which a first segment is placed between two separators, illustrating a method for manufacturing an electrode assembly according to some embodiments of this application;

[0041] Figure 10 A front view of a method for manufacturing an electrode assembly provided in some embodiments of this application, in which a first segment is placed between two separators;

[0042] Figure 11 A schematic diagram of the structure of a method for manufacturing an electrode assembly provided in some embodiments of this application, showing the placement of a second segment between two separators;

[0043] Figure 12 A front view of a method for manufacturing an electrode assembly provided in some embodiments of this application, showing the second segment being placed between two separators;

[0044] Figure 13 A flowchart illustrating step S200 of the method for manufacturing an electrode assembly provided in some embodiments of this application in other embodiments;

[0045] Figure 14 This is a schematic flowchart illustrating a method for manufacturing an electrode assembly according to some embodiments of this application.

[0046] Icons: 1000 - Vehicle; 100 - Battery; 10 - Housing; 11 - First Housing Body; 12 - Second Housing Body; 20 - Battery Cell; 21 - Casing; 211 - Shell; 2111 - Opening; 212 - End Cap; 22 - Electrode Assembly; 221 - Negative Electrode; 2211 - Straight Section; 2212 - Bending Section; 2213 - Negative Electrode Lug; 222 - Separator; 223 - Positive Electrode; 22 31-First segment; 2232-Second segment; 2232a-Winding start end; 2233-First non-polar area; 2234-Second non-polar area; 2235-Positive electrode tab; 224-Straight area; 225-Bending area; 23-Positive electrode terminal; 24-Negative electrode terminal; 25-Pressure relief mechanism; 200-Controller; 300-Motor; 400-Winding needle; X-Winding direction; Y-First direction. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0048] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0049] In this application, the reference to "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 application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0050] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0051] In this application, 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, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0052] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0053] In this application, "multiple" means two or more (including two).

[0054] In this application, the battery cell may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of this application are not limited to these. The battery cell may be cylindrical, flat, cuboid, or other shapes, etc., and the embodiments of this application are not limited to these. Battery cells are generally divided into three types according to their packaging method: cylindrical battery cells, square battery cells, and pouch battery cells, and the embodiments of this application are not limited to these.

[0055] The battery mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this application may include a battery module or a battery pack. A battery generally includes a housing for encapsulating one or more battery cells or multiple battery modules. The housing can prevent liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0056] A battery cell includes a casing, electrode assembly, and electrolyte. The casing houses the electrode assembly and electrolyte. The electrode assembly consists of a positive electrode, a negative electrode, and a separator. The battery cell primarily functions by the movement of metal ions between the positive and negative electrodes. The positive electrode includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector, and the portion of the positive current collector without the coating serves as the positive electrode tab, through which electrical energy is input or output. Taking a lithium-ion battery as an example, the positive current collector can be made of aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector, and the portion of the negative current collector without the coating serves as the negative electrode tab, through which electrical energy is input or output. The negative electrode current collector can be made of copper, and the negative electrode active material can be carbon or silicon, etc. To ensure that a large current can be passed without melting, there are multiple positive electrode tabs stacked together, and there are multiple negative electrode tabs stacked together.

[0057] Furthermore, the electrode assembly can be a wound structure or a stacked structure, and the embodiments of this application are not limited thereto.

[0058] Batteries possess outstanding advantages such as high energy density, low environmental pollution, high power density, long lifespan, wide applicability, and low self-discharge coefficient, making them a crucial component of today's new energy development. A battery cell is assembled from positive electrode sheets, negative electrode sheets, and a separator through methods such as winding or stacking to form an electrode assembly (bare cell), which is then housed in a casing and finally injected with electrolyte. Among these, the wound electrode assembly structure offers advantages such as ease of assembly, low manufacturing difficulty, and high production efficiency, thus its widespread application. However, with the continuous development of battery technology, higher requirements are being placed on the performance and safety of battery cells. Therefore, the performance and safety of the electrode assembly determine the performance and safety of the battery cell.

[0059] The inventors discovered that in wound electrode assemblies, negative and positive electrode sheets are typically stacked and continuously wound together. However, this type of electrode assembly results in a large bending radius at the corner of the inner ring of the positive electrode sheet, making the positive electrode sheet prone to breakage and puncturing the separator. Furthermore, it causes lithium plating at the corner of the positive electrode sheet during use, leading to poor performance of the electrode assembly and significant safety hazards.

[0060] To address the poor performance and significant safety hazards of electrode assemblies, existing technologies involve cutting the positive and negative electrode sheets into multiple regularly sized positive and negative electrode units, then thermally bonding these units to both sides of a separator. This results in a staggered arrangement of the positive and negative electrode units along the separator's extension direction. Finally, the separator is wound to form a wound electrode assembly, thus resolving the issue of lithium plating or breakage at the corners of the inner ring of the positive electrode. However, this structure requires separate thermal bonding of the positive and negative electrode units to both sides of the separator, demanding high manufacturing precision and precise control of the spacing between the positive and negative electrode units. This increases the manufacturing difficulty and hinders production efficiency.

[0061] Based on the above considerations, in order to solve the problems of lithium plating risk and low production efficiency of wound electrode assemblies during use, the inventors, after in-depth research, designed an electrode assembly. The electrode assembly includes a negative electrode sheet and a positive electrode sheet, which are wound together along a winding direction to form the electrode assembly. The electrode assembly has a flat region and a bent region connected to the flat region. The negative electrode sheet is continuous in the winding direction and includes multiple flat portions stacked in the flat region. The positive electrode sheet includes a first segment and a second segment spaced apart and arranged sequentially along the winding direction. The first segment is located in the flat region and stacked between two adjacent flat portions. The second segment is stacked with the negative electrode sheet and continuously wound along the winding direction. In the opposite direction of the winding direction, a first non-electrode region is formed between the second segment and the adjacent first segment. At least a portion of the first non-electrode region is located in the bent region.

[0062] In this type of electrode assembly, the electrode assembly is a wound structure formed by winding a negative electrode sheet and a positive electrode sheet together along the winding direction. The negative electrode sheet is continuously arranged along the winding direction, and the positive electrode sheet has a first segment and a second segment arranged sequentially and at intervals along the winding direction. By placing the first segment entirely in the straight region, and continuously winding the second segment and the negative electrode sheet together along the winding direction, and placing at least a portion of the first non-electrode area formed between the second segment and the adjacent first segment in the bending region of the electrode assembly, the inner ring of the electrode assembly forms a structure in which the straight portion of the negative electrode sheet and the first segment of the positive electrode sheet are stacked together, and the outer ring of the electrode assembly forms a structure in which the negative electrode sheet and the second segment of the positive electrode sheet are wound together. The electrode assembly with this structure can alleviate the phenomenon of large tension caused by the large bending degree of the inner ring of the positive electrode sheet in the bending region, thereby effectively reducing the risk of lithium plating or breakage and puncture of the separator during use of the portion of the inner ring of the positive electrode sheet located in the bending region, thus improving the performance and safety of the electrode assembly.

[0063] Furthermore, this type of electrode assembly does not require the entire positive electrode sheet to be set up as multiple first segments wound with the negative electrode sheet. Instead, the inner ring of the electrode assembly can be set up as a structure in which the straight part of the negative electrode sheet and the first segment of the positive electrode sheet are stacked on top of each other. This can effectively ensure the energy density requirements of the electrode assembly and reduce the positional accuracy requirements between the positive and negative electrode sheets, thereby reducing the manufacturing difficulty of the electrode assembly. This can greatly optimize the production cycle of the electrode assembly, improve the production efficiency of the electrode assembly, and meet the production capacity requirements.

[0064] The electrode assembly disclosed in this application can be used, but is not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can be composed of battery cells and batteries disclosed in this application. This effectively reduces the risk of lithium plating in the battery cells during use, thereby improving the safety of the battery cells.

[0065] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0066] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0067] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 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 100 is disposed inside the vehicle 1000, and the battery 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, the battery 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0068] In some embodiments of this application, the battery 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0069] Please refer to Figure 2 , Figure 2 This is an exploded view of the structure of a battery 100 provided in some embodiments of this application. The battery 100 includes a housing 10 and battery cells 20, with the battery cells 20 housed within the housing 10. The housing 10 provides assembly space for the battery cells 20, and can employ various structures. In some embodiments, the housing 10 may include a first housing body 11 and a second housing body 12, which overlap each other, collectively defining an assembly space for accommodating the battery cells 20. The second housing body 12 may be a hollow structure open at one end, and the first housing body 11 may be a plate-like structure, covering the open side of the second housing body 12 so that the first housing body 11 and the second housing body 12 jointly define the assembly space; alternatively, both the first housing body 11 and the second housing body 12 may be hollow structures open on one side, with the open side of the first housing body 11 covering the open side of the second housing body 12. Of course, the box 10 formed by the first box body 11 and the second box body 12 can be of various shapes, such as cylinder, cuboid, etc.

[0070] In battery 100, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 20 are connected in both series and parallel configurations. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, battery 100 can also be composed of multiple battery cells 20 first connected in series, parallel, or in a mixed manner to form a battery module, and then multiple battery modules are connected in series, parallel, or in a mixed manner to form a whole, which is also housed within the housing 10. Battery 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.

[0071] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 20 can be cylindrical, flat, cuboid, or other shapes. For example, in... Figure 2 In the middle, the battery cell 20 has a cuboid structure.

[0072] Please refer to Figure 3 , Figure 3 The image shows an exploded view of the structure of a battery cell 20 provided in some embodiments of this application. The battery cell 20 includes a housing 21 and an electrode assembly 22, the housing 21 being used to house the electrode assembly 22.

[0073] The outer casing 21 can also be used to contain electrolytes, such as electrolyte solutions. The outer casing 21 can have various structural forms. The outer casing 21 can also be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0074] In some embodiments, the housing 21 may include a housing 211 and an end cap 212. The housing 211 is a hollow structure with an opening 2111 on one side, and the end cap 212 covers the opening 2111 of the housing 211 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 22 and the electrolyte.

[0075] When assembling the battery cell 20, the electrode assembly 22 can be placed into the housing 211 first, and the electrolyte can be filled into the housing 211. Then, the end cap 212 can be closed onto the opening 2111 of the housing 211.

[0076] The housing 211 can have various shapes, such as a cylinder or a cuboid. The shape of the housing 211 can be determined based on the specific shape of the electrode assembly 22. For example, if the electrode assembly 22 is a cylindrical structure, a cylindrical housing can be used; if the electrode assembly 22 is a cuboid structure, a cuboid housing can be used. Of course, the end cap 212 can also have various structures, such as a plate-like structure or a hollow structure with an opening 2111 at one end. For example, in... Figure 3 In the middle, the electrode assembly 22 has a cuboid structure, and the corresponding housing 211 has a cuboid structure. The end cap 212 has a rectangular plate structure and is closed at the opening 2111 of the housing 211.

[0077] In some embodiments, the battery cell 20 may further include a positive electrode terminal 23, a negative electrode terminal 24, and a pressure relief mechanism 25, all of which are mounted on the end cap 212. The positive electrode terminal 23 and the negative electrode terminal 24 are both used for electrical connection with the electrode assembly 22. The pressure relief mechanism 25 is used to release the internal pressure of the battery cell 20 when the internal pressure or temperature reaches a predetermined value.

[0078] For example, such as Figure 3 As shown, the pressure relief mechanism 25 is located between the positive electrode terminal 23 and the negative electrode terminal 24. The pressure relief mechanism 25 can be a component such as an explosion-proof valve, explosion-proof disc, gas valve, pressure relief valve, or safety valve.

[0079] Understandably, the outer casing 21 is not limited to the structure described above. It can also have other structures. For example, the outer casing 21 may include a housing 211 and two end caps 212. The housing 211 is a hollow structure with openings 2111 on opposite sides. One end cap 212 corresponds to one opening 2111 of the housing 211 and forms a sealed connection, creating a sealed space for accommodating the electrode assembly 22 and the electrolyte. In this structure, the positive electrode terminal 23 and the negative electrode terminal 24 can be mounted on the same end cap 212 or on different end caps 212. A pressure relief mechanism 25 can be mounted on one end cap 212 or both end caps 212 can have a pressure relief mechanism 25 mounted on them.

[0080] In this embodiment of the application, the electrode assembly 22 housed within the housing 21 can be one or more. For example, in... Figure 3 In the middle, there are two electrode components 22, which are stacked together.

[0081] It should be noted that electrode assembly 22 is the component within battery cell 20 where the electrochemical reaction occurs. Please refer to... Figure 4 , Figure 4 This is a schematic diagram of the structure of an electrode assembly 22 provided in some embodiments of this application. The electrode assembly 22 may include a negative electrode 221, a separator 222, and a positive electrode 223. The electrode assembly 22 can be a wound structure formed by winding the negative electrode 221, the separator 222, and the positive electrode 223, or a stacked structure formed by arranging the negative electrode 221, the separator 222, and the positive electrode 223 in layers. (Exemplary example follows.) Figure 4 In the middle, the electrode assembly 22 is a wound structure formed by winding the negative electrode 221, the separator 222 and the positive electrode 223.

[0082] According to some embodiments of this application, please refer to Figure 3 and Figure 4As shown. This application provides an electrode assembly 22, which includes a negative electrode 221 and a positive electrode 223. The negative electrode 221 and the positive electrode 223 are wound along the winding direction X to form the electrode assembly 22. The electrode assembly 22 has a flat region 224 and a bending region 225 connected to the flat region 224. The negative electrode 221 is continuous in the winding direction X and includes a plurality of flat portions 2211 stacked in the flat region 224. The positive electrode 223 includes a first segment 2231 and a second segment 2232 arranged sequentially and spaced apart along the winding direction X. The first segment 2231 is located in the straight region 224 and is stacked between two adjacent straight portions 2211. The second segment 2232 is stacked with the negative electrode 221 and continuously wound along the winding direction X. In the opposite direction of the winding direction X, the second segment 2232 and the adjacent first segment 2231 form a first non-electrode region 2233. At least a portion of the first non-electrode region 2233 is located in the bending region 225.

[0083] The electrode assembly 22 may further include a separating membrane 222 disposed between the negative electrode 221 and the positive electrode 223. For example, in... Figure 4 In this structure, the negative electrode 221, the separator 222, and the positive electrode 223 are wound together to form a flat electrode assembly 22. This results in the electrode assembly 22 having a straight region 224 and two bent regions 225 connected to the two ends of the straight region 224. Specifically, the straight region 224 is the straight portion of the electrode assembly 22, and the bent regions 225 are the bent portions at both ends of the electrode assembly 22. Of course, in other embodiments, the electrode assembly 22 can also be a cylindrical structure or a cuboid structure, etc.

[0084] The negative electrode 221 is continuous in the winding direction X, and includes multiple straight portions 2211 stacked in the straight region 224. That is, the portion of the negative electrode 221 located in the straight region 224 after continuous winding is the straight portion 2211, and the multiple straight portions 2211 of the negative electrode 221 located in the straight region 224 are stacked along the first direction Y, which is the thickness direction of the straight portion 2211 of the negative electrode 221. Correspondingly, the negative electrode 221 also has multiple bent portions 2212 located in the bending region 225. In the winding direction X, the straight portions 2211 and the bent portions 2212 are alternately arranged and connected. That is, along the winding direction X, two adjacent straight portions 2211 are connected by a bent portion 2212. It should be noted that the winding direction X is unidirectional, that is, the winding direction X is the direction in which the negative electrode 221 and the positive electrode 223 are continuously wound from the inside to the outside.

[0085] The first segment 2231 and the second segment 2232 are spaced apart along the winding direction X, meaning the positive electrode plate 223 is divided into a first segment 2231 and a second segment 2232 that are disconnected and spaced apart along the winding direction X. It should be noted that there can be one or more first segments 2231. When there are multiple first segments 2231, they are spaced apart along the winding direction X, and the multiple first segments 2231 as a whole are spaced apart from the second segment 2232 along the winding direction X. In other words, the multiple first segments 2231 and the second segment 2232 are arranged sequentially and spaced apart along the winding direction X. For example, in... Figure 4 In the middle, the positive electrode 223 includes two first segments 2231, and the innermost ring of the electrode assembly 22 is the negative electrode 221.

[0086] The first segment 2231 is located in the flat region 224 and is stacked between two adjacent flat portions 2211. That is, the first segment 2231 of the positive electrode 223 and the flat portion 2211 of the negative electrode 221 are stacked on top of each other, and the first segment 2231 of the positive electrode 223 is entirely located within the flat region 224. In other words, in the winding direction X and the opposite direction of the winding direction X, neither end of the first segment 2231 extends into the bending region 225. It should be noted that in the winding direction X and the opposite direction of the winding direction X, the connection position of the two ends of the first segment 2231 at the flat region 224 and the bending region 225 also belongs to the first segment 2231 being located within the flat region 224.

[0087] The second segment 2232 is stacked with the negative electrode 221 and continuously wound along the winding direction X. That is, the second segment 2232 of the positive electrode 223 and the negative electrode 221 are continuously wound along the winding direction X, so that the second segment 2232 is wrapped around the outside of the first segment 2231.

[0088] Along the opposite direction of the winding direction X, a first non-polar region 2233 is formed between the second segment 2232 and the adjacent first segment 2231. At least a portion of the first non-polar region 2233 is located in the bending region 225. That is, in the opposite direction of the winding direction X, since the second segment 2232 and its adjacent first segment 2231 are spaced apart, a blank area (i.e., the first non-polar region 2233) without a positive electrode 223 is formed. At least a portion of the first non-polar region 2233 is located in the bending region 225. That is, the first non-polar region 2233 can be entirely located in the bending region 225 or partially located in the bending region 225. In other words, in the opposite direction of the winding direction X, the first non-polar region 2233 can extend into the straight region 224 or not extend into the straight region 224.

[0089] For example, the first non-polar region 2233 is entirely located within the bending region 225, that is, in the opposite directions of the winding direction X and the winding direction X, the first non-polar region 2233 does not extend into the straight region 224.

[0090] Electrode assembly 22 is a wound structure formed by winding a negative electrode 221 and a positive electrode 223 together along the winding direction X. The negative electrode 221 is continuously arranged along the winding direction X, and the positive electrode 223 has a first segment 2231 and a second segment 2232 arranged at intervals along the winding direction X. The first segment 2231 is entirely arranged in the flat region 224, and the second segment 2232 is continuously wound with the negative electrode 221 along the winding direction X. The second segment 2232 is then connected to the adjacent first segment 2231. At least a portion of the first non-polar region 2233 formed between sections 2231 is disposed within the bending region 225 of the electrode assembly 22, thereby forming a structure in which the straight portion 2211 of the negative electrode 221 and the first section 2231 of the positive electrode 223 are stacked on each other in the inner ring of the electrode assembly 22, and forming a structure in which the second section 2232 of the negative electrode 221 and the positive electrode 223 are wound around each other in the outer ring of the electrode assembly 22. The electrode assembly 22 with this structure can, on the one hand, alleviate the problem of the negative electrode 221 and the second section 2232 of the positive electrode 223. The large bending degree of the inner ring of the positive electrode 223 in the bending area 225 generates a large tension, which effectively reduces the risk of lithium plating or breakage of the inner ring of the positive electrode 223 within the bending area 225 during use, thereby improving the performance and safety of the electrode assembly 22. On the other hand, it is not necessary to set the entire positive electrode 223 as multiple first segments 2231 wound with the negative electrode 221. It is only necessary to set the inner ring of the electrode assembly 22 as the straight part 2211 of the negative electrode 221 and the first segment 2231 of the positive electrode 223 stacked on each other. This can effectively ensure the energy density requirements of the electrode assembly 22 and reduce the positional accuracy requirements between the positive electrode 223 and the negative electrode 221, thereby reducing the manufacturing difficulty of the electrode assembly 22 and greatly optimizing the production cycle of the electrode assembly 22, which is conducive to improving the production efficiency of the electrode assembly 22 and meeting the production capacity requirements.

[0091] According to some embodiments of this application, see Figure 4 As shown, the winding start end 2232a of the second segment 2232 is located in the straight area 224.

[0092] Specifically, the starting point 2232a of the second segment 2232 is located in the flat region 224. That is, the starting point of the winding of the second segment 2232 of the positive electrode 223 and the negative electrode 221 is located within the flat region 224. In other words, in the opposite direction of the winding direction X, the starting point 2232a of the second segment 2232 does not extend into the bending region 225. It should be noted that the connection point between the starting point 2232a of the second segment 2232 and the bending region 225 also falls within the flat region 224.

[0093] By setting the winding start end 2232a of the second segment 2232 and the negative electrode 221 within the flat region 224, that is, the second segment 2232 of the positive electrode 223 and the negative electrode 221 are wound from the flat region 224 of the electrode assembly 22, the bending phenomenon of the winding start end 2232a of the second segment 2232 can be effectively alleviated, thereby reducing the risk of lithium plating or breakage at the winding start end 2232a of the second segment 2232, which is conducive to improving the performance and safety of the electrode assembly 22.

[0094] According to some embodiments of this application, please continue to refer to Figure 4 As shown, the positive electrode 223 includes a plurality of first segments 2231. Along the winding direction X, the plurality of first segments 2231 are spaced apart, and a second non-polar region 2234 is formed between two adjacent first segments 2231, at least a portion of the second non-polar region 2234 being located in the bending region 225.

[0095] The positive electrode 223 has a plurality of first segments 2231 spaced apart along the winding direction X. That is, the plurality of first segments 2231 are spaced apart along the winding direction X, and the plurality of first segments 2231 and the second segment 2232 are also spaced apart along the winding direction X. In other words, the plurality of first segments 2231 are arranged sequentially and spaced apart along the winding direction X, and then arranged sequentially and spaced apart with the second segment 2232 along the winding direction X.

[0096] Along the winding direction X, a second non-polar region 2234 is formed between two adjacent first segments 2231. At least a portion of the second non-polar region 2234 is located in the bending region 225. That is, in the winding direction X, two adjacent first segments 2231 are spaced apart to form a blank area (i.e., the second non-polar region 2234) without a positive electrode 223. At least a portion of the second non-polar region 2234 is located in the bending region 225. That is, the second non-polar region 2234 can be entirely located in the bending region 225 or partially located in the bending region 225. In other words, in the opposite direction of the winding direction X, the second non-polar region 2234 can extend into the straight region 224 or not extend into the straight region 224.

[0097] For example, in Figure 4 In the positive electrode 223, there are two first segments 2231. The two first segments 2231 are spaced apart along the winding direction X and then spaced apart from the second segment 2232. Each first segment 2231 is stacked between two different straight portions 2211 of the negative electrode 221 along the first direction Y, and the two first segments 2231 are parallel to each other. Of course, in some embodiments, the number of first segments 2231 may also be three, four, or five, etc.

[0098] For example, in Figure 4 In the middle, the second non-polar region 2234 is located entirely within the bending region 225, that is, in the opposite directions of the winding direction X and the winding direction X, the second non-polar region 2234 does not extend into the straight region 224.

[0099] The positive electrode 223 has a plurality of first segments 2231 spaced apart along the winding direction X, and a second non-electrode region 2234 formed between two adjacent first segments 2231 is disposed within the bending region 225. That is, the plurality of first segments 2231 are spaced apart along the winding direction X, and the plurality of first segments 2231 as a whole are spaced apart from the second segments 2232 along the winding direction X. This results in the inner ring of the electrode assembly 22 forming a structure in which the plurality of first segments 2231 and the plurality of straight portions 2211 of the negative electrode 221 are alternately stacked. This can effectively reduce the risk of lithium plating or breakage at the multiple bending positions of the inner ring of the positive electrode 223 located within the bending region 225, which is beneficial to further improve the performance and safety of the electrode assembly 22.

[0100] According to some embodiments of this application, see Figure 4 As shown, the electrode assembly 22 also includes a separator 222. The separator 222 is disposed between the negative electrode 221 and the positive electrode 223 to separate the negative electrode 221 and the positive electrode 223.

[0101] The separator 222 is made of insulating material to provide insulation and separation between the negative electrode 221 and the positive electrode 223. For example, the separator 222 can be made of PP (polypropylene) or PE (polyethylene).

[0102] The electrode assembly 22 is also provided with a separator 222 located between the negative electrode 221 and the positive electrode 223, which can effectively separate the negative electrode 221 and the positive electrode 223, thereby reducing the phenomenon of short circuit between the negative electrode 221 and the positive electrode 223, and thus helping to reduce the safety hazards of the electrode assembly 22 during use.

[0103] According to some embodiments of this application, the first segment 2231 is adhered to the separator 222.

[0104] For example, the first segment 2231 can be bonded to the separator 222 using an adhesive or tape. In other words, by providing an adhesive or tape on the first segment 2231, the first segment 2231 can be bonded to the separator 222 when it is wound with the negative electrode plate 221.

[0105] By bonding the first segment 2231 of the positive electrode 223 to the separator 222, the phenomenon of the first segment 2231 shifting or slipping during use or manufacturing can be effectively reduced, thereby improving the production quality and performance of the electrode assembly 22.

[0106] In some embodiments, the first segment 2231 is bonded to the release membrane 222 by an adhesive layer located on opposite sides in the length direction of the first segment 2231, and / or the adhesive layer is located on opposite sides in the width direction of the first segment 2231.

[0107] The adhesive layer is located on opposite sides along the length of the first segment 2231, and / or on opposite sides along the width of the first segment 2231. That is, the adhesive layer is disposed on the long and / or short sides of the first segment 2231, meaning it is located on the outer edge of the first segment 2231. Alternatively, the adhesive layer can be disposed on all four or two sides of the first segment 2231, and the two sides can be either long or short sides. It can also be disposed at the four corners of the first segment 2231. This allows the first segment 2231 to be bonded to the separator 222 via the adhesive layer, eliminating the need to place the adhesive layer on the side of the first segment 2231 facing the separator 222, i.e., eliminating the need to place the adhesive layer on the coating area of ​​the first segment 2231, and thus eliminating the need to place the adhesive layer on the active material layer of the first segment 2231, thereby reducing the impact of the adhesive layer on the active material layer of the first segment 2231.

[0108] For example, the adhesive layer can be made of fluorocarbon resin, hinge resin or hot melt resin, etc.

[0109] By placing the adhesive layer for bonding the first segment 2231 and the separator 222 on both sides of the first segment 2231 in the length or width direction, this structure can effectively reduce the impact of the adhesive layer on the coating area on the first segment 2231, thereby ensuring the wetting effect of the electrolyte on the coating area of ​​the first segment 2231.

[0110] According to some embodiments of this application, please refer to Figure 4As shown, both the first segment 2231 and the second segment 2232 have a positive electrode tab 2235. Along the stacking direction of the multiple straight segments 2211, the positive electrode tabs 2235 of the first segment 2231 and the positive electrode tabs 2235 of the second segment 2232 are stacked.

[0111] The area of ​​the current collector in the first segment 2231 and the current collector in the second segment 2232 that is not coated with the active material layer is the positive electrode tab 2235. By stacking the positive electrode tab 2235 of the first segment 2231 and the positive electrode tab 2235 of the second segment 2232 together, the positive electrode tab of the positive electrode plate 223 is formed, which serves as the positive output electrode of the positive electrode plate 223.

[0112] The positive electrode tab 2235 of the first segment 2231 and the positive electrode tab 2235 of the second segment 2232 are stacked along the stacking direction of multiple straight segments 2211, that is, the positive electrode tab 2235 of the first segment 2231 and the positive electrode tab 2235 of the second segment 2232 are stacked along the first direction Y (i.e. the thickness direction of the straight segment 2211).

[0113] It should be noted that the negative electrode sheet 221 has multiple negative electrode tabs 2213, and the negative electrode tabs 2213 are disposed on the straight portion 2211 of the negative electrode sheet 221. The negative electrode tabs 2213 are the areas of the current collector of the negative electrode sheet 221 that are not coated with the active material layer. The multiple negative electrode tabs 2213 of the negative electrode sheet 221 are stacked along the first direction Y, and the multiple negative electrode tabs 2213 are interconnected to form the negative electrode tabs of the negative electrode sheet 221, which serve as the negative output electrode of the negative electrode sheet 221, thereby facilitating the connection of the negative electrode tabs 2213 to the negative electrode terminal 24. For example, the multiple negative electrode tabs 2213 of the negative electrode sheet 221 can be connected together by an adhesive process or a welding process.

[0114] By stacking the tabs of the first segment 2231 and the second segment 2232 together along the stacking direction of multiple straight portions 2211, it is easy to connect the tabs of the first segment 2231 and the second segment 2232 to other components, which helps to reduce the manufacturing difficulty of the electrode assembly 22, so as to realize the electrical energy input or output of the first segment 2231 and the second segment 2232 of the positive electrode 223.

[0115] In some embodiments, two adjacent positive electrode tabs 2235 are bonded or welded along the stacking direction of the plurality of straight portions 2211.

[0116] Among them, two adjacent positive electrode tabs 2235 are bonded or welded. That is, after the positive electrode tabs 2235 of the first segment 2231 and the positive electrode tabs 2235 of the second segment 2232 are stacked along the first direction Y, the two adjacent positive electrode tabs 2235 are connected into a whole by bonding or welding so that the positive electrode tabs 2235 can be connected to the positive electrode terminal 23.

[0117] For example, two adjacent positive electrode tabs 2235 can be bonded together with glue or tape.

[0118] For example, two adjacent positive electrode tabs 2235 can be welded using laser welding or ultrasonic welding processes.

[0119] By bonding or welding two adjacent tabs arranged in layers to each other, the tabs of the first segment 2231 and the tabs of the second segment 2232 are made into an integral structure. This structure facilitates the connection of the tabs of the first segment 2231 and the tabs of the second segment 2232 to other components. On the other hand, it helps to alleviate the phenomenon of movement or slippage of the first segment 2231 of the positive electrode 223 during use, thereby improving the performance of the electrode assembly 22.

[0120] According to some embodiments of this application, this application also provides a battery cell 20, including a housing 21 and an electrode assembly 22 of any of the above schemes, wherein the electrode assembly 22 is housed within the housing 21.

[0121] According to some embodiments of this application, this application also provides a battery 100, including a plurality of battery cells 20 of any of the above schemes, wherein the plurality of battery cells 20 are connected in series, parallel or mixed.

[0122] The battery 100 may also include a housing 10, in which multiple battery cells 20 are housed.

[0123] According to some embodiments of this application, this application also provides an electrical device, including a battery 100 of any of the above schemes, and the battery 100 is used to provide electrical energy to the electrical device.

[0124] The electrical device can be any of the aforementioned devices or systems that use battery 100.

[0125] According to some embodiments of this application, see Figure 3 and Figure 4As shown, this application provides an electrode assembly 22, which includes a negative electrode 221, a separator 222, and a positive electrode 223. The negative electrode 221 and the positive electrode 223 are wound along the winding direction X to form the electrode assembly 22, and the separator 222 is disposed between the negative electrode 221 and the positive electrode 223. The electrode assembly 22 has a flat region 224 and two bent regions 225 connected to both ends of the flat region 224. The negative electrode 221 is continuous in the winding direction X and includes a plurality of flat portions 2211 stacked in the flat region 224. The positive electrode 223 includes a first segment 2231 and a second segment 2232 arranged sequentially and at intervals along the winding direction X. The first segment 2231 is located in the flat region 224 and is stacked between two adjacent flat portions 2211. The second segment 2232 is stacked with the negative electrode 221 and continuously wound along the winding direction X. In the opposite direction of the winding direction X, a first non-polar region 2233 is formed between the second segment 2232 and the adjacent first segment 2231. The first non-polar region 2233 is entirely located in the bending region 225. The winding start end 2232a of the second segment 2232 is located in the flat region 224. The positive electrode 223 includes multiple first segments 2231, which are arranged at intervals along the winding direction X. A second non-polar region 2234 is formed between two adjacent first segments 2231. The second non-polar region 2234 is entirely located in the bending region 225.

[0126] According to some embodiments of this application, this application also provides a method for manufacturing an electrode assembly 22, referring to... Figure 5 , Figure 5 This is a schematic flowchart of a method for manufacturing an electrode assembly 22 provided in some embodiments of this application. The manufacturing method includes:

[0127] S100: Provides negative electrode plate 221 and positive electrode plate 223;

[0128] S200: The negative electrode 221 and the positive electrode 223 are wound along the winding direction X to form the electrode assembly 22.

[0129] The electrode assembly 22 has a flat region 224 and a bent region 225 connected to the flat region 224. The negative electrode 221 is continuous in the winding direction X. The negative electrode 221 includes a plurality of flat portions 2211 stacked in the flat region 224. The positive electrode 223 includes a first segment 2231 and a second segment 2232 arranged at intervals along the winding direction X. The first segment 2231 is located in the flat region 224 and is stacked between two adjacent flat portions 2211. The second segment 2232 is stacked with the negative electrode 221 and is continuously wound along the winding direction X. In the opposite direction of the winding direction X, the second segment 2232 and the adjacent first segment 2231 form a first non-electrode region 2233. At least a portion of the first non-electrode region 2233 is located in the bent region 225.

[0130] For example, see Figure 4 As shown, the electrode assembly 22 manufactured by the above manufacturing method has two first segments 2231. The two first segments 2231 and the second segment 2232 are arranged sequentially and at intervals along the winding direction X. The first segment 2231 is entirely located within the flat region 224. Along the winding direction X, a second non-polar region 2234 is formed between the two first segments 2231, and the second non-polar region 2234 is entirely located within the bending region 225. The first non-polar region 2233 formed between the first segment 2231 adjacent to the second segment 2232 is entirely located within the bending region 225, and the winding start end 2232a of the second segment 2232 is located within the flat region 224.

[0131] In the electrode assembly 22 manufactured by the above manufacturing method, the positive electrode 223 includes a first segment 2231 and a second segment 2232 arranged sequentially and spaced apart along the winding direction X. The first segment 2231 is entirely disposed within the flat region 224 and stacked between two adjacent flat portions 2211 of the negative electrode 221. The first non-electrode region 2233 formed between the second segment 2232 and the adjacent first segment 2231 is disposed within the bending region 225 of the electrode assembly 22, thereby forming the flat portion 2211 of the negative electrode 221 and the positive electrode 2232 within the inner ring of the electrode assembly 22. The first segment 2231 of 23 has a stacked structure, and the outer ring of the electrode assembly 22 forms a structure in which the negative electrode 221 and the second segment 2232 of the positive electrode 223 are wrapped together. The electrode assembly 22 with this structure can alleviate the phenomenon that the inner ring of the positive electrode 223 has a large bending degree in the bending area 225 and generates a large tension. Therefore, during the use of the electrode assembly 22, it can effectively reduce the risk of lithium plating or breakage of the inner ring of the positive electrode 223 located in the bending area 225, which may puncture the separator 222, thereby improving the performance and safety of the electrode assembly 22.

[0132] According to some embodiments of this application, refer to Figure 6 , Figure 6 This is a schematic flowchart of step S200 of a method for manufacturing an electrode assembly 22 provided in some embodiments of this application. Step S200: Winding the negative electrode 221 and the positive electrode 223 along the winding direction X includes:

[0133] S210: Provides two separator membranes 222;

[0134] S220: The negative electrode 221 and two separators 222 are wound along the winding direction X (e.g., ...). Figure 7 and Figure 8 As shown, Figure 7 This is a schematic diagram of the structure of the electrode assembly 22 provided in some embodiments of this application, showing the winding of the negative electrode sheet 221 and the two separator films 222. Figure 8 A method for manufacturing an electrode assembly 22 provided in some embodiments of this application (a front view of the wound negative electrode sheet 221 and two separator films 222);

[0135] S230: During the winding of the negative electrode sheet 221 and the two separators 222, the first segment 2231 and the second segment 2232 are sequentially placed between the two separators 222 (e.g., Figures 9-12 As shown, Figure 9 This is a schematic diagram of the structure of a method for manufacturing an electrode assembly 22 according to some embodiments of this application, in which a first segment 2231 is placed between two separators 222. Figure 10 The method of manufacturing the electrode assembly 22 provided in some embodiments of this application is shown in the front view of placing the first segment 2231 between two separators 222. Figure 11 This is a schematic diagram of the structure of the method for manufacturing the electrode assembly 22 provided in some embodiments of this application, in which the second segment 2232 is placed between two separators 222. Figure 12 The method of manufacturing the electrode assembly 22 provided in some embodiments of this application is shown in the front view of placing the second segment 2232 between two separator membranes 222.

[0136] The separator 222 is disposed between the negative electrode 221 and the positive electrode 223 to separate the negative electrode 221 and the positive electrode 223.

[0137] See Figure 7 and Figure 8As shown, in step S220, two separators 222 are stacked on one side of the negative electrode plate 221. Then, the negative electrode plate 221 and the two separators 222 are wound using a winding needle 400 so that the innermost ring of the electrode assembly 22 is the negative electrode plate 221. That is, the negative electrode plate 221 and the separators 222 are first wound to a certain length so that the innermost ring of the electrode assembly 22 is the negative electrode plate 221. The specific structure of the winding needle 400 can be found in related technologies and will not be described in detail here.

[0138] See Figures 9-12 As shown, in step S230, the first segment 2231 is first inserted between the two separators 222, so that the first segment 2231 can be stacked between the two straight portions 2211 of the negative electrode 221 during the winding of the two separators 222 and the negative electrode 221.

[0139] For example, there are two first segments 2231. Thus, the two first segments 2231 are placed sequentially between the two separators 222, so that the two first segments 2231 are spaced apart along the winding direction X. Then, the second segment 2232 is inserted between the two separators 222, so that the second segment 2232 can be continuously wound with the negative electrode plate 221.

[0140] Optionally, after one of the two first segments 2231 is placed between the two separators 222, the other first segment 2231 is placed between the two separators 222 after a 21mm-27mm interval, so that the second non-polar region 2234 formed between the two first segments 2231 is entirely located within the bending region 225 of the electrode assembly 22. Similarly, the second segment 2232 is then placed between the two separators 222 after a 21mm-27mm interval, so that the first non-polar region 2233 formed between the first segment 2231 and the second segment 2232 is entirely located within the bending region 225 of the electrode assembly 22.

[0141] In the above manufacturing method, during the winding of the negative electrode 221 and the positive electrode 223, the negative electrode 221 is first wound with two separators 222. During the winding process, the first segment 2231 and the second segment 2232 of the positive electrode 223 are sequentially placed between the two separators 222, thereby forming an inner ring of the electrode assembly 22 where the straight portion 2211 of the negative electrode 221 and the first segment 2231 of the positive electrode 223 are stacked on each other, and the outer ring of the electrode assembly 22 is a structure in which the negative electrode 221 and the second segment 2232 of the positive electrode 223 are wound together. This manufacturing method can eliminate the process of thermally bonding the first segment 2231 and the second segment 2232 of the positive electrode 223 with the separators 222 before winding, thereby simplifying the manufacturing process of the electrode assembly 22, optimizing the production cycle of the electrode assembly 22, and effectively improving the production efficiency of the electrode assembly 22 to meet the production capacity requirements.

[0142] According to some embodiments of this application, refer to Figure 13 , Figure 13 The flowchart of step S200 of the method for manufacturing the electrode assembly 22 provided in some embodiments of this application is shown in other embodiments. In step S230: before the first segment 2231 and the second segment 2232 are sequentially placed between the two separators 222 during the winding of the negative electrode sheet 221 and the two separators 222, the method for manufacturing the electrode assembly 22 further includes:

[0143] S240: An adhesive layer is provided on the first segment 2231 so that the first segment 2231 is adhered to the release membrane 222.

[0144] The adhesive layer is located on opposite sides along the length of the first segment 2231, and / or on opposite sides along the width of the first segment 2231. For example, the adhesive layer may be disposed on one or both sides of the first segment 2231, and the two sides may be either long or short sides. It may also be disposed at the four corners of the first segment 2231, so that the first segment 2231 can be bonded to the two release films 222 when placed between them.

[0145] For example, the adhesive layer can be made of fluorocarbon resin, hinge resin or hot melt resin, etc.

[0146] In the above manufacturing method, before placing the first segment 2231 of the positive electrode 223 between the two separators 222, an adhesive layer for bonding with the separators 222 is provided on the first segment 2231, so that the first segment 2231 can bond with the separators 222 when it is placed between the two separators 222. This can effectively alleviate the phenomenon of the first segment 2231 shifting or slipping during the winding process, thereby improving the production quality of the electrode assembly 22.

[0147] According to some embodiments of this application, refer to Figure 4 Please refer to further details. Figure 14 , Figure 14 This is a schematic flowchart illustrating a method for manufacturing an electrode assembly 22 according to some embodiments of this application. Both the first segment 2231 and the second segment 2232 have positive electrode tabs 2235. Along the stacking direction of the plurality of straight portions 2211, the positive electrode tabs 2235 of the first segment 2231 and the positive electrode tabs 2235 of the second segment 2232 are stacked. After step S200: winding the negative electrode sheet 221 and the positive electrode sheet 223 along the winding direction X, the method for manufacturing the electrode assembly 22 further includes:

[0148] S300: Bond or weld two adjacent positive electrode tabs 2235.

[0149] In this process, two adjacent positive electrode tabs 2235 are bonded or welded together. That is, after the first segment 2231 and the second segment 2232 of the negative electrode 221 and the positive electrode 223 are wound together, the positive electrode tabs 2235 of the first segment 2231 and the positive electrode tabs 2235 of the second segment 2232 are first stacked along the stacking direction of multiple straight portions 2211 (i.e., the first direction Y). Then, two adjacent positive electrode tabs 2235 in the stacked positive electrode tabs 2235 are bonded or welded together so that the multiple positive electrode tabs 2235 form a whole, thereby forming the positive electrode tab of the positive electrode tab.

[0150] For example, if two adjacent positive electrode tabs 2235 are to be bonded together, they can be bonded together with glue or tape; if two adjacent positive electrode tabs 2235 are to be welded together, they can be welded using laser welding or ultrasonic welding.

[0151] In the above manufacturing method, after the negative electrode 221 and the positive electrode 223 are wound, the multiple tabs stacked along the stacking direction of the multiple straight portions 2211 are connected together by bonding or welding. The electrode assembly 22 manufactured by this method makes the tabs of the first segment 2231 and the tabs of the second segment 2232 form an integral structure. This facilitates the connection of the tabs of the first segment 2231 and the tabs of the second segment 2232 with other components, and also helps to alleviate the phenomenon of movement or slippage of the first segment 2231 of the positive electrode 223 during use, thereby improving the performance of the electrode assembly 22.

[0152] It should be noted that the relevant structure of the electrode assembly 22 manufactured by the manufacturing method provided in the above embodiments can be found in the electrode assembly 22 provided in the foregoing embodiments, and will not be repeated here.

[0153] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0154] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An electrode assembly, characterized in that, The electrode assembly includes a negative electrode sheet and a positive electrode sheet, which are wound together along a winding direction to form the electrode assembly. The electrode assembly has a flat region and a bent region connected to the flat region. The negative electrode sheet is continuous in the winding direction and includes a plurality of flat portions stacked in the flat region. The positive electrode sheet includes a first segment and a second segment arranged sequentially and spaced apart along the winding direction. The first segment is located in the flat region and stacked between two adjacent flat portions. The second segment is stacked with the negative electrode sheet and continuously wound along the winding direction. In the opposite direction of the winding direction, a first non-electrode region is formed between the second segment and the adjacent first segment. At least a portion of the first non-electrode region is located in the bending region. The positive electrode includes a plurality of first segments. Along the winding direction, the plurality of first segments are spaced apart. A second non-electrode area is formed between two adjacent first segments. At least part of the second non-electrode area is located in the bending area. The innermost ring of the electrode assembly is the negative electrode. The negative electrode is provided on the inner side of both the first non-electrode area and the second non-electrode area. The electrode assembly further includes a separator, which is disposed between the negative electrode and the positive electrode to separate the negative electrode and the positive electrode, and the first segment is adhered to the separator. The first segment is bonded to the release membrane by an adhesive layer located on opposite sides along the length of the first segment; and / or The adhesive layers are located on opposite sides in the width direction of the first segment.

2. The electrode assembly according to claim 1, characterized in that, The starting end of the second segment is located in the flat area.

3. The electrode assembly according to claim 1 or 2, characterized in that, Both the first segment and the second segment have a positive electrode tab, and the positive electrode tabs of the first segment and the second segment are stacked together along the stacking direction of the plurality of straight portions.

4. The electrode assembly according to claim 3, characterized in that, Along the stacking direction of the plurality of straight portions, two adjacent positive electrode tabs are bonded or welded together.

5. A single battery cell, characterized in that, include: shell; as well as The electrode assembly according to any one of claims 1-4 is housed within the housing.

6. A battery, characterized in that, It includes multiple battery cells as described in claim 5.

7. An electrical device, characterized in that, Includes the battery according to claim 6.

8. A method for manufacturing an electrode assembly, applicable to the electrode assembly according to any one of claims 1-4, characterized in that, include: Provide the negative electrode and the positive electrode; The negative electrode and the positive electrode are wound along the winding direction to form the electrode assembly, the electrode assembly having a flat region and a bent region connected to the flat region, the negative electrode being continuous in the winding direction, and the negative electrode including a plurality of flat portions stacked in the flat region; The positive electrode includes a first segment and a second segment arranged at intervals along the winding direction. The first segment is located in the straight region and stacked between two adjacent straight portions. The second segment is stacked with the negative electrode and continuously wound along the winding direction. In the opposite direction of the winding direction, a first non-electrode region is formed between the second segment and the adjacent first segment. At least a portion of the first non-electrode region is located in the bending region.

9. The method for manufacturing the electrode assembly according to claim 8, characterized in that, The winding of the negative electrode and the positive electrode along the winding direction includes: Provide two of the aforementioned separator membranes; The negative electrode sheet and the two separators are wound along the winding direction; During the winding of the negative electrode sheet and the two separators, the first segment and the second segment are sequentially placed between the two separators; The separator is disposed between the negative electrode and the positive electrode to separate them.

10. The method for manufacturing the electrode assembly according to claim 9, characterized in that, Before sequentially placing the first segment and the second segment between the two separators during the winding of the negative electrode sheet and the two separators, the method for manufacturing the electrode assembly further includes: An adhesive layer is provided on the first segment so that the first segment is adhered to the release membrane.

11. The method for manufacturing the electrode assembly according to claim 9 or 10, characterized in that, Both the first segment and the second segment have positive electrode tabs, and the positive electrode tabs of the first segment and the positive electrode tabs of the second segment are stacked along the stacking direction of the plurality of straight portions; After winding the negative electrode and the positive electrode along the winding direction, the method for manufacturing the electrode assembly further includes: Adhesive or weld two adjacent positive electrode tabs.

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