Electrode assembly, battery cell, battery, and electric device

Abstract

The application provides an electrode assembly, a battery monomer, a battery and an electric device, and belongs to the technical field of batteries. The electrode assembly comprises two pole pieces with opposite polarities and a separator for isolating the two pole pieces, and the two pole pieces and the separator form a main body and two pole lugs after being wound in a winding direction. The pole lugs and the main body are arranged in a first direction, the pole lugs comprise a plurality of pole lug portions arranged at intervals in the winding direction, the pole lug portions are bent relative to the first direction, at least part of the plurality of pole lug portions are arranged in a stack in the first direction, and at least one side of the pole lug portion in the thickness direction of the pole lug portion is provided with a protrusion. By arranging the protrusion on the pole lug portion, the thickness of the plurality of pole lug portions stacked together can be increased after the pole lug portion is bent, and the phenomenon that the local thickness of the pole lug is small can be alleviated, so as to reduce the risk of the pole lug being welded through in the subsequent assembly process, and the phenomenon that the electrode assembly is damaged is reduced, so as to improve the production quality of the battery monomer with the electrode assembly.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to an electrode assembly, 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. A battery consists of a single cell, and within the casing of the single cell are electrode assemblies. By connecting the electrode assemblies to the casing, the battery cell can input or output electrical energy. However, in the current production and assembly process, electrode assemblies are often damaged, resulting in poor production quality of the battery cells and hindering the improvement of the product qualification rate. Summary of the Invention

[0003] This application provides an electrode assembly, a battery cell, a battery, and an electrical device, which can effectively improve the production quality of battery cells.

[0004] In a first aspect, embodiments of this application provide an electrode assembly, including two electrodes with opposite polarities and a spacer for isolating the two electrodes. The two electrodes and the spacer are wound along a winding direction to form a main body and two tabs. The tabs and the main body are arranged along a first direction. The tabs include a plurality of tab portions spaced apart along the winding direction. The tab portions are bent relative to the first direction. At least a portion of the plurality of tab portions are stacked along the first direction, and a protrusion is formed on at least one side of the tab portion in its thickness direction.

[0005] In the above technical solution, two electrodes with opposite polarities and a separator are wound along a winding direction to form a wound electrode assembly, so that the electrode assembly has a main body and two tabs, and the tabs and the main body are arranged along a first direction. The tabs are provided with multiple tab portions spaced apart along the winding direction, and the tab portions are bent relative to the first direction so that at least a portion of the multiple tab portions can be stacked along the first direction. By providing a protrusion on at least one side of the tab portion, the thickness of the stacked multiple tab portions is increased, and the phenomenon of localized thinness after stacking can be alleviated. This improves the production quality of the tabs, reduces the risk of the tabs being burned through during subsequent assembly and processing, and thus helps reduce the damage to the electrode assembly. It also helps improve the connection stability and assembly quality between the electrode assembly and other components of the battery cell, thereby improving the production quality and operational stability of the battery cell with this electrode assembly.

[0006] In some embodiments, a plurality of protrusions are formed on at least one side of the electrode portion along the thickness direction of the electrode portion.

[0007] In the above technical solution, by providing multiple protrusions on at least one side of the electrode tab, the electrode tab is bent relative to the first direction and multiple electrode tabs are stacked along the first direction, which can effectively increase the area with cavities between two adjacent electrode tabs that are stacked together. This is beneficial to further improve the overall thickness of the electrode tab in the first direction and improve the uniformity of the electrode tab thickness, thereby further alleviating the phenomenon of the electrode tab being burned through during subsequent assembly and processing.

[0008] In some embodiments, along the thickness direction of the tab portion, the projected area of ​​the tab portion is S1, and the sum of the projected areas of the plurality of protrusions on the tab portion is S2, satisfying that S2 / S1≥0.5.

[0009] In the above technical solution, by setting the sum of the projected areas of multiple protrusions on the tab in the thickness direction of the tab to be greater than or equal to half of the projected area of ​​the tab in the thickness direction of the tab, that is, the area occupied by multiple protrusions on the tab is half or more of the tab, so that there is a sufficient area on the tab to be provided with protrusions, thereby making the tab have sufficient thickness after multiple tabs are stacked along the first direction, and effectively improving the uniformity of the tab thickness, so as to reduce the risk of the tab being soldered through during subsequent assembly.

[0010] In some embodiments, the tab portion includes a main body region that does not overlap with the projection of the protrusion in the thickness direction of the tab portion, and the protrusion protrudes from the main body region along the thickness direction of the tab portion; along the thickness direction of the tab portion, the maximum size of the tab portion is D1, and the thickness of the main body region is D2, satisfying that 2≤D1 / D2≤8.

[0011] In the above technical solution, the tab has a main body area that does not overlap with the projection of the protrusion in the thickness direction of the tab, and the protrusion protrudes from the main body area in the thickness direction of the tab. That is, the main body area of ​​the tab is the area of ​​the tab without the protrusion. By setting the maximum dimension of the tab in the thickness direction to 2 to 8 times the thickness of the main body area, that is, the maximum thickness of the tab after the protrusion is provided is 2 to 8 times the thickness of the main body area of ​​the tab, the thickness of the multiple tabs of the tab stacked together in the first direction can be effectively increased after the tab is bent relative to the first direction, so as to increase the thickness of the tab and thus effectively alleviate the phenomenon of the tab being burned through in the subsequent assembly process.

[0012] In some embodiments, the tab portion is formed with multiple rows of protrusions, each row of protrusions including a plurality of protrusions spaced apart.

[0013] In the above technical solution, by setting multiple rows of protrusions on the electrode tab, and each row of protrusions includes multiple protrusions spaced apart, the multiple protrusions on the electrode tab are arranged in an orderly manner. This effectively increases the area with cavities between two adjacent electrode tabs after the multiple electrode tabs are stacked along the first direction. This is beneficial to further increase the overall thickness of the electrode tab in the first direction and can effectively improve the uniformity of the electrode tab thickness, thereby reducing the phenomenon of the electrode tab being burned through during subsequent assembly.

[0014] In some embodiments, the maximum dimension of the protrusion in the direction perpendicular to the thickness direction of the tab is W1, satisfying 0.3mm≤W1≤2mm.

[0015] In the above technical solution, by setting the maximum size of the protrusion in the direction perpendicular to the thickness of the electrode tab to 0.3mm to 3mm, that is, the maximum size of the protrusion in its radial direction is 0.3mm to 3mm, on the one hand, it can alleviate the phenomenon that the processing difficulty is too high due to the size of the protrusion, thereby reducing the processing difficulty of the electrode tab, and on the other hand, it can alleviate the phenomenon that the number of protrusions on the electrode tab is limited due to the size of the protrusion.

[0016] In some embodiments, the tab portion is formed with a plurality of protrusions arranged at intervals, and the two ends of the protrusions extend to the two ends of the tab portion in a direction perpendicular to the arrangement direction of the plurality of protrusions.

[0017] In the above technical solution, multiple protrusions are formed at intervals on the electrode tab, and the two ends of the protrusions extend to the two ends of the electrode tab. That is, the protrusions are strip-shaped structures set on the electrode tab, so as to realize the structure of multiple protrusions on the electrode tab. This structure helps to reduce the difficulty of setting protrusions on the electrode tab and improve the processing efficiency of the electrode tab.

[0018] In some embodiments, along the arrangement direction of the plurality of protrusions, the width of the protrusion is W2, satisfying 0.3mm≤W2≤2mm.

[0019] In the above technical solution, by setting the width of the protrusion in the arrangement direction of multiple protrusions to 0.3mm to 3mm, that is, the size of the protrusion in the direction perpendicular to the extension direction of the protrusion is 0.3mm to 3mm, on the one hand, it can alleviate the phenomenon that the processing difficulty is too high due to the width of the protrusion being too small, thereby reducing the processing difficulty of the electrode tab, and on the other hand, it can alleviate the phenomenon that the number of protrusions on the electrode tab is limited due to the width of the protrusion being too large.

[0020] In some embodiments, along the thickness direction of the tab portion, the tab portion includes a plurality of foils stacked together, a protrusion is formed on one side of the foils, and a recess is formed on the other side at a position corresponding to the protrusion. In two adjacent foils, the protrusion of one foil is accommodated in the recess of the other foil. The protrusion located on one side of the tab portion along the thickness direction of the tab portion is the protrusion.

[0021] In the above technical solution, by setting the tab portion as a structure of multiple foil layers, with a protrusion on one side of the foil and a concave side on the other side, the protrusions and concave sides of two adjacent foils can be interlocked after the multiple foils are stacked, so that the tab portion has a protrusion on one side in the thickness direction. The tab portion with this structure can effectively increase the thickness and structural strength of the tab portion itself. Thus, after the multiple tab portions of the tab are stacked along the first direction, the overall thickness and structural strength of the tab portion can be further increased, so as to further reduce the risk of the tab portion being soldered through during subsequent assembly.

[0022] In some embodiments, a plurality of the foils are welded together to form the protrusions and recesses on the foils.

[0023] In the above technical solution, multiple foils stacked together are connected by welding, and protrusions and concaves are formed at the welding points of the multiple foils. On the one hand, this helps to improve the connection strength and stability between the multiple foils, and on the other hand, it helps to reduce the processing difficulty of forming concaves and protrusions on the foils, thereby optimizing the production cycle of the electrode sheet and effectively improving the production efficiency of the electrode sheet.

[0024] In some embodiments, the electrode includes a main body portion, a plurality of electrode tabs are connected to the main body portion, and the main body portions of two electrodes and the separator are wound along the winding direction to form the main body portion. The main body portion includes a substrate and an active material layer disposed on at least one side of the substrate. The plurality of foils include a first foil and a second foil stacked together. The first foil is connected to one end of the substrate in the first direction and is integrally formed with the substrate. The second foil is separately disposed from the substrate.

[0025] In the above technical solution, the multiple foils include a first foil integrally formed with the substrate of the main body of the electrode sheet. In actual production, an area without an active material layer can be reserved on the substrate, so that the first foil can be set in the area. Then, the second foil can be stacked on one side of the first foil, so that the first foil can provide a connection support point for the second foil, thereby improving the thickness and structural strength of the electrode tab. Electrodes with this structure can effectively reduce the process difficulty of connecting the electrode tab to the substrate, which is conducive to improving the production efficiency of the electrode assembly.

[0026] In some embodiments, the substrate includes a coating area and a spacer area, the coating area and the spacer area being arranged along the first direction, the active material layer being disposed on the coating area, and the spacer area connecting the coating area and the first foil.

[0027] In the above technical solution, by setting a coated area with an active material layer and an uncoated spacer area on the substrate, the first foil of the tab can be connected to the coated area through the spacer area, so that the tab and the active material layer are spaced apart in the first direction. The electrode assembly with this structure can, on the one hand, isolate the stress generated by the tab during bending processing relative to the first direction through the spacer area, thereby reducing the risk of breakage of the active material layer on the coated area. On the other hand, it can reduce the impact on the active material layer during the subsequent welding of the tab with other components, thereby alleviating the phenomenon of damage to the active material layer, and thus helping to improve the production quality of the electrode assembly.

[0028] In some embodiments, along the thickness direction of the tab portion, the thickness of the first foil is D3 and the thickness of the second foil is D4, satisfying that 0.5≤D3 / D4≤2.

[0029] In the above technical solution, by setting the thickness of the first foil to 0.5 to 2 times the thickness of the second foil (i.e., the thickness of the first foil is 0.5 to 2 times the thickness of the second foil), the assembly difficulty of connecting the first and second foils due to the large difference in thickness between them can be alleviated, thereby reducing the processing difficulty of the tabs in this structure. Furthermore, this solution alleviates both the damage to the second foil during welding caused by the excessive thickness of the first foil compared to the second foil, and the damage to the first foil during welding caused by the excessive thickness of the second foil compared to the first foil.

[0030] In some embodiments, along a direction perpendicular to the thickness direction of the tab, the end of the second foil near the substrate does not extend beyond the end of the first foil connected to the substrate.

[0031] In the above technical solution, by setting the second foil in a direction perpendicular to the thickness direction of the tab portion to not exceed the end of the first foil connected to the substrate, the interference between the second foil and the active material layer disposed on one side of the substrate can be effectively mitigated, thereby reducing the risk of the active material layer being damaged by the second foil.

[0032] In some embodiments, along the direction perpendicular to the thickness direction of the tab portion, the distance between the end of the first foil away from the substrate and the end of the second foil away from the substrate is L, satisfying that L≤2mm.

[0033] In the above technical solution, by setting the distance between the end of the first foil furthest from the substrate and the end of the second foil furthest from the substrate in the direction perpendicular to the thickness direction of the electrode tab to be less than or equal to 2mm, that is, the dimension by which the end of the first foil furthest from the substrate extends beyond the end of the second foil furthest from the substrate is less than or equal to 2mm, or the dimension by which the end of the second foil furthest from the substrate extends beyond the end of the first foil furthest from the substrate is less than or equal to 2mm, the phenomenon that the first foil extends too far beyond the second foil or the second foil extends too far beyond the first foil due to the excessive length of the first foil or the second foil can be alleviated, which would result in the electrode tab being excessively long or inserted backwards into the electrode assembly. This is beneficial to improving the production quality and reliability of the electrode assembly.

[0034] In some embodiments, the first foil and the second foil are made of the same material.

[0035] In the above technical solution, by setting the first foil and the second foil to the same material, the polarity of the tab can be stabilized on the one hand, and the process difficulty of connecting the first foil and the second foil can be reduced on the other hand.

[0036] In some embodiments, the electrode includes a main body portion, and a plurality of electrode tabs are connected to one end of the main body portion in the first direction. The main body portions of two electrodes and the spacer are wound together along the winding direction to form the main body. The main body portion includes a substrate and an active material layer disposed on at least one side of the substrate. The substrate includes a coating area and a spacer area. The coating area and the spacer area are arranged along the first direction. The active material layer is disposed in the coating area. The spacer area connects the coating area and the electrode tabs.

[0037] In the above technical solution, by setting a coated area with an active material layer and a spacer area without an active material layer on the substrate, the tab can be connected to the coated area through the spacer area, so that the tab and the active material layer are spaced apart in the first direction. The electrode assembly with this structure can, on the one hand, isolate the stress generated by the tab during bending processing relative to the first direction through the spacer area, so as to reduce the risk of breakage of the active material layer on the coated area. On the other hand, it can reduce the impact on the active material layer during the subsequent welding of the tab with other components, thereby alleviating the phenomenon of damage to the active material layer, and thus helping to improve the production quality of the electrode assembly.

[0038] In some embodiments, the tab portion is integrally formed with the spacer region.

[0039] In the above technical solution, by setting the tab part as an integrally formed structure with the spacer area of ​​the substrate, the tab part can be part of the substrate in the actual production process. The tab part can be set in the area where no active material layer is set after leaving an area on the substrate, thereby reducing the process difficulty of connecting the tab part to the substrate and improving the production efficiency of the electrode assembly.

[0040] In some embodiments, along the thickness direction of the tab portion, a groove is formed on the side of the tab portion opposite to the protrusion and corresponding to the position of the protrusion.

[0041] In the above technical solution, by providing a groove on the side of the tab away from the protrusion and corresponding to the position of the protrusion, the tab of this structure can form a protrusion on the tab through processes such as stamping or rolling. On the one hand, it helps to reduce the processing difficulty of the tab and improve the processing efficiency of the tab. On the other hand, it eliminates the need to add material to set a protrusion on one side of the tab, thereby reducing the production cost of the tab and reducing its weight.

[0042] In some embodiments, along the first direction, in two adjacent tabs, the protrusion of one tab is misaligned with the groove of the other tab.

[0043] In the above technical solution, by setting the protrusion of one electrode tab and the groove of the other electrode tab in two adjacent electrode tabs in the first direction to be staggered, the phenomenon of mutual cancellation after the protrusion and groove overlap can be effectively alleviated, so that the electrode tab has sufficient thickness in the first direction, thereby helping to reduce the risk of the electrode tab of the electrode assembly being soldered through during subsequent assembly.

[0044] In some embodiments, along the first direction, the thickness of the tab is D5, satisfying 0.2mm≤D5≤2.5mm.

[0045] In the above technical solution, by setting the thickness of the tab in the first direction to 0.2mm to 2.5mm, on the one hand, it can alleviate the risk of the tab being burned through due to its small thickness, thereby reducing the risk of damage to the electrode assembly during subsequent assembly. On the other hand, it can alleviate the problem of the tab occupying too much space due to its large thickness, thereby optimizing the internal space of the battery cell with this electrode assembly and improving the energy density of the battery cell.

[0046] In some embodiments, along the first direction, the two electrodes are respectively disposed at both ends of the body.

[0047] In the above technical solution, by setting the two tabs of the electrode assembly at the two ends of the main body in the first direction, that is, the two tabs are formed at the two ends of the electrode assembly in the first direction, it is convenient to assemble the electrode assembly in the future. This helps to reduce the assembly difficulty of the battery cell with this electrode assembly, and can reduce the phenomenon of interference or mutual contact between the two tabs, thereby helping to reduce the risk of short circuit of the electrode assembly.

[0048] In some embodiments, the body is cylindrical.

[0049] In the above technical solution, the main body of the electrode assembly is set as a cylindrical structure to facilitate subsequent processing to form a cylindrical battery cell.

[0050] 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.

[0051] In some embodiments, the battery cell further includes a current collector; the current collector is disposed between the housing and the electrode tab along the first direction, and the current collector connects the housing and the electrode tab.

[0052] In the above technical solution, by setting a current collector inside the casing of the battery cell, the casing and the electrode assembly are connected through the current collector, thereby enabling the input or output of electrical energy of the battery cell. This structure is simple, easy to implement, and helps to reduce the assembly difficulty between the electrode and the casing.

[0053] In some embodiments, the current collector is welded to the tab, and along the first direction, the thickness of the tab is D5 and the thickness of the current collector is D6, satisfying that D6≤1.5D5.

[0054] In the above technical solution, by setting the thickness of the current collector in the first direction to be less than or equal to 1.5 times the thickness of the tab in the first direction, the phenomenon that the welding power required to weld the current collector and the tab is too large due to the thickness of the current collector being too large than the thickness of the tab can be alleviated. This can effectively reduce the risk of the tab being welded through, thereby reducing the phenomenon of electrode assembly being damaged and improving the production quality of battery cells.

[0055] In some embodiments, the current collector is welded to the tab to form a solder mark, and along the first direction, the solder mark covers at least one of the protrusions of the tab.

[0056] In the above technical solution, by setting the weld mark formed by welding the current collector and the electrode to each other as a protrusion covering at least one electrode in the first direction, that is, in the first direction, the position where the current collector and the electrode are welded to each other corresponds to the protrusion of at least one electrode, so that the position where the current collector and the electrode are welded to each other is located in the area where the electrode is thickened by the protrusion, which helps to further reduce the risk of the electrode being welded through during the assembly process.

[0057] Thirdly, embodiments of this application also provide a battery, including the aforementioned battery cell.

[0058] Fourthly, embodiments of this application also provide an electrical device, including the battery described above. Attached Figure Description

[0059] 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.

[0060] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0061] Figure 2 Exploded views of the battery structure provided in some embodiments of this application;

[0062] Figure 3 Exploded views of the structure of a single battery cell provided in some embodiments of this application;

[0063] Figure 4 Cross-sectional views of electrode assemblies provided in some embodiments of this application;

[0064] Figure 5 Cross-sectional views of electrode assemblies provided in some embodiments of this application;

[0065] Figure 6 This is a schematic diagram of the structure of the electrode assembly provided in some embodiments of this application during the winding process;

[0066] Figure 7 A schematic diagram of the unfolded structure of the electrode sheet of the electrode assembly provided in some embodiments of this application;

[0067] Figure 8 Partial cross-sectional views of the electrode sheets provided in some embodiments of this application after being unfolded;

[0068] Figure 9 This is a schematic diagram of the structure of the tab provided in some embodiments of this application;

[0069] Figure 10 A front view of the tab provided in some embodiments of this application;

[0070] Figure 11 This application provides schematic diagrams of the structure of the tab portion in some embodiments.

[0071] Figure 12 A front view of the tab provided in some embodiments of this application;

[0072] Figure 13 This is a schematic diagram of the structure of the tab provided in some embodiments of this application;

[0073] Figure 14 A front view of the tab provided in some embodiments of this application;

[0074] Figure 15 Partial cross-sectional view of the electrode sheet after unfolding, provided for other embodiments of this application;

[0075] Figure 16 A cross-sectional view of the electrode tab of an electrode sheet provided in some other embodiments of this application;

[0076] Figure 17 A cross-sectional view of multiple tab portions of an electrode assembly provided in some embodiments of this application after being stacked;

[0077] Figure 18 This is a schematic diagram showing the connection between the current collector and the electrode assembly tabs provided in some embodiments of this application.

[0078] 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 - Electrode Sheet; 2211 - Main Body; 22111 - Substrate; 22111a - Coating Area; 22111b - Spacer Area; 22112 - Active Material Layer; 2212 - Tab; 22121 -Electrode tab; 22121a-Protrusion; 22121b-Groove; 22121c-Main body area; 22121d-Foil material; 22121e-Protrusion; 22121f-Recess; 22121g-First foil material; 22121h-Second foil material; 222-Isolator; 223-Main body; 23-Current collector; 24-Solder mark; 200-Controller; 300-Motor; X-First direction; Y-Wound direction; Z-Thickness direction of electrode tab. Detailed Implementation

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] In this application, "multiple" means two or more (including two).

[0086] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0087] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0088] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0089] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0090] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0091] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0092] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0093] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0094] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0095] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0096] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0097] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc.

[0098] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0099] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0100] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0101] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride, and ceramic.

[0102] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0103] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0104] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0105] In some implementations, the electrode assembly is a stacked structure.

[0106] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0107] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0108] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0109] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0110] 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.

[0111] In some embodiments, the battery can be a battery module, and when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0112] In some embodiments, the battery can be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0113] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0114] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0115] Batteries possess outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide applicability, and low self-discharge coefficient, making them a crucial component in the development of new energy sources. Each battery cell typically houses a current collector within its casing. During assembly, the electrode tabs of the electrode assembly are welded to the current collector, which is then connected to the casing to enable the input or output of electrical energy into the battery cell. This facilitates assembly and reduces the complexity of battery cell assembly.

[0116] For typical battery cells, electrode assemblies are usually welded to current collectors via tabs to achieve electrical connection. Tabs are typically formed by stacking multiple tab pieces. To reduce the assembly difficulty between the electrode assembly and the current collector, especially for cylindrical electrode assemblies, a flattening or smoothing process is often used during battery cell production to flatten or smooth the multiple tab pieces. This improves the flatness of the tabs, ensuring they are formed at one end of the electrode assembly, thus reducing the welding difficulty between the tabs and the current collector. However, the flattening or smoothing process in existing electrode assemblies easily leads to localized areas of insufficient thickness in the tabs. Furthermore, even when multiple tab pieces are tightly fitted together, the overall thickness of the tabs can be insufficient. This makes it easy for the tabs to be welded through during the welding process to the current collector, potentially damaging the electrode assembly and resulting in poor battery cell production quality, which is detrimental to improving the product qualification rate of battery cells.

[0117] Based on the above considerations, in order to solve the problem of poor production quality of battery cells, this application provides an electrode assembly, including two electrode sheets with opposite polarities and a separator for isolating the two electrode sheets. The two electrode sheets and the separator are wound along a winding direction to form a main body and two tabs. The tabs and the main body are arranged along a first direction. The tabs include a plurality of tab portions spaced apart along the winding direction. The tab portions are bent relative to the first direction. At least a portion of the plurality of tab portions are stacked along the first direction, and the tab portions have a protrusion formed on at least one side in their thickness direction.

[0118] In this type of electrode structure, two electrodes with opposite polarities and a separator are wound along a winding direction to form a wound electrode assembly, giving the electrode assembly a main body and two tabs, with the tabs and the main body arranged along a first direction. Each tab has multiple tab portions spaced apart along the winding direction, and these tab portions are bent relative to the first direction, allowing at least a portion of the multiple tab portions to be stacked along the first direction. By providing a protrusion on at least one side of each tab portion, the thickness of the stacked tab portions is increased, mitigating the phenomenon of locally thinner tab portions after stacking. This improves the manufacturing quality of the tabs, reduces the risk of burn-through during subsequent assembly, and helps reduce damage to the electrode assembly. Furthermore, it enhances the connection stability and assembly quality between the electrode assembly and other components of the battery cell, thereby improving the manufacturing quality and operational stability of the battery cell with this electrode assembly.

[0119] The electrode plates disclosed in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can be composed of electrode assemblies, battery cells, or batteries disclosed in this application. This effectively alleviates the phenomenon of electrode tabs being soldered through during the production and assembly of battery cells, thereby improving the production quality of battery cells.

[0120] 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.

[0121] 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.

[0122] 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. The battery 100 can be disposed 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 or general power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 controls 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.

[0123] In some embodiments of this application, the battery 100 can not only serve as the operating power or 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.

[0124] Please refer to Figure 2 , Figure 2 The image shows an exploded view of the structure of a battery 100 provided in some embodiments of this application. The battery 100 may include a housing 10 and battery cells 20, the battery cells 20 being housed within the housing 10.

[0125] The housing 10 provides assembly space for the battery cell 20, and can adopt 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, and together define an assembly space for accommodating the battery cell 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, with the first housing body 11 covering the open side of the second housing body 12 so that the first housing body 11 and the second housing body 12 together define the assembly space; the first housing body 11 and the second housing body 12 may also be hollow structures both 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 housing 10 formed by the first housing body 11 and the second housing body 12 can be of various shapes, such as a cylinder, a cuboid, etc. For example, in Figure 2 The middle box 10 is rectangular in shape.

[0126] In battery 100, there can be one or more battery cells 20 disposed within housing 10. When there are multiple battery cells 20 disposed within housing 10, they can be connected in series, in parallel, or in a mixed manner. A mixed connection means that multiple battery cells 20 are connected in both series and parallel. Multiple battery cells 20 can be directly connected in series, in parallel, or in a mixed manner, and then the whole assembly of multiple battery cells 20 is housed within housing 10. Alternatively, battery 100 can also be composed of multiple battery cells 20 first connected in series, in parallel, or in a mixed manner to form a battery module, and then multiple battery modules are connected in series, in parallel, or in a mixed manner to form a whole, which is then housed within housing 10. Battery 100 may also include other structures. For example, battery 100 may also include a busbar component for connecting multiple battery cells 20 to achieve electrical connection between multiple battery cells 20.

[0127] 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 the battery cell 20 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 cylindrical structure.

[0128] Reference Figure 2 Please refer to further details. Figure 3 , Figure 3 This is an exploded view of the structure of a battery cell 20 provided in some embodiments of this application. The battery cell 20 may include a housing 21 and an electrode assembly 22, the electrode assembly 22 being housed within the housing 21.

[0129] The outer shell 21 can also be used to contain electrolytes, such as electrolyte solutions. The outer shell 21 can have various structural forms, such as a cylinder, cuboid, or prism. Similarly, the outer shell 21 can be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy.

[0130] In some embodiments, the housing 21 may include a housing 211 and an end cap 212. The housing 211 has an internal cavity with an opening 2111 for accommodating the electrode assembly 22. That is, the housing 211 is a hollow structure with an opening 2111 on one side. 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.

[0131] 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 to complete the assembly of the battery cell 20.

[0132] 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 211 can be used; if the electrode assembly 22 is a cuboid structure, a cuboid housing 211 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 one end open 2111. For example, in... Figure 3 In the middle, the electrode assembly 22 has a cylindrical structure, and the corresponding housing 211 has a cylindrical structure. The end cap 212 has a cylindrical plate-like structure, and the end cap 212 covers the opening 2111 of the housing 211.

[0133] Of course, it is understandable that the outer casing 21 is not limited to the structure described above. The outer casing 21 can also be other structures. For example, the outer casing 21 includes a housing 211 and two end caps 212. The housing 211 is a hollow structure with openings 2111 on both sides opposite to each other. One end cap 212 is fitted onto one 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.

[0134] In some embodiments, the housing 21 may further include a positive electrode terminal and a negative electrode terminal. The positive electrode terminal may be mounted on the end cap 212, and the negative electrode terminal may be mounted on the end of the housing 211 opposite to the end cap 212. Alternatively, the positive electrode terminal may be mounted on the end of the housing 211 opposite to the end cap 212, and the negative electrode terminal may be mounted on the end cap 212. Both the positive and negative electrode terminals may be mounted on the end cap 212 or both on the end of the housing 211 opposite to the end cap 212. Both the positive and negative electrode terminals are used for electrical connection with the electrode assembly 22 to realize the input or output of electrical energy of the battery cell 20. The positive and negative electrode terminals may be directly connected to the electrode assembly 22, such as by welding or contact, or indirectly connected, such as by first connecting the positive and negative electrode terminals to other components and then contacting or welding them to the electrode assembly 22 through those other components.

[0135] Among them, Figure 3 In the battery cell 20, the current collector 23 may also include a current collector 23, which is housed in the housing 21. The current collector 23 is used to connect the positive electrode terminal or the negative electrode terminal of the electrode assembly 22 and the housing 21 to realize the input or output of electrical energy of the battery cell 20.

[0136] The current collector 23 serves to connect the positive electrode terminal of the electrode assembly 22 and the housing 21 or to connect the negative electrode terminal of the electrode assembly 22 and the housing 21. The connection between the current collector 23 and the electrode assembly 22 and the positive or negative electrode terminal of the housing 21 can be in various ways, such as welding, contacting or bonding.

[0137] For example, the battery cell 20 may include two current collectors 23. The electrode assembly 22 is connected to the positive electrode terminal and the negative electrode terminal of the housing 21 through the two current collectors 23, respectively. That is, the electrode assembly 22 is connected to the positive electrode terminal of the housing 21 through one current collector 23 and to the negative electrode terminal of the housing 21 through the other current collector 23, thereby enabling the positive and negative electrodes of the battery cell 20 to be output or input respectively.

[0138] In some embodiments, the battery cell 20 may further include a pressure relief mechanism, which may be mounted on the end cap 212 or on the housing 211. Similarly, there may be one or more pressure relief mechanisms. The pressure relief mechanism is used to release the pressure inside the battery cell 20.

[0139] For example, the pressure relief mechanism may be a pressure relief component such as an explosion-proof valve, an explosion-proof disc, a gas valve, a pressure relief valve, or a safety valve.

[0140] It should be noted that the electrode assembly 22 is the component in the battery cell 20 where the electrochemical reaction takes place. The structure of the electrode assembly 22 can be various; for example, the electrode assembly 22 can be a wound structure formed by winding or a stacked structure formed by layering. Similarly, the shape of the electrode assembly 22 can also be various; for example, the shape of the electrode assembly 22 can be a cylindrical structure, an elliptical structure, or a cuboid structure, etc.

[0141] In some embodiments, refer to Figure 3 Please refer to further details. Figure 4 and Figure 5 , Figure 4 This is a cross-sectional view of the electrode assembly 22 provided in some embodiments of this application. Figure 5 This is a cross-sectional view of an electrode assembly 22 provided in some embodiments of this application. The electrode assembly 22 is a wound structure formed by winding, and the shape of the electrode assembly 22 is cylindrical.

[0142] The electrode assembly 22 may include two electrodes 221 with opposite polarities, which are wound around a central axis extending in the first direction X to form a wound structure. That is, the two electrodes 221 with opposite polarities are the positive and negative electrodes of the electrode assembly 22, respectively, and the positive and negative electrodes are wound together to form the wound structure. Of course, in other embodiments, the electrode assembly 22 may also be a stacked structure formed by layering two electrodes 221 with opposite polarities.

[0143] Optionally, the electrode assembly 22 may also include an isolator 222 disposed between the two electrodes 221 to insulate and isolate the two electrodes 221, thereby effectively reducing the risk of short circuit during use of the electrode assembly 22.

[0144] For example, the material of the spacer 222 can be various, such as polypropylene or polyethylene.

[0145] According to some embodiments of this application, refer to Figure 4 and Figure 5 Please refer to further details. Figure 6 , Figure 7 and Figure 8 , Figure 6 This is a schematic diagram of the structure of the electrode assembly 22 provided in some embodiments of this application during the winding process. Figure 7 This is a schematic diagram of the unfolded structure of the electrode plate 221 of the electrode assembly 22 provided in some embodiments of this application. Figure 8This is a partial cross-sectional view of the electrode 221 provided in some embodiments of this application after unfolding. This application provides an electrode assembly 22, including two electrode pieces 221 with opposite polarities and a spacer 222 for isolating the two electrode pieces 221. The two electrode pieces 221 and the spacer 222 are wound along a winding direction Y to form a main body 223 and two tabs 2212. The tabs 2212 and the main body 223 are arranged along a first direction X. The tabs 2212 include a plurality of tab portions 22121 spaced apart along the winding direction Y. The tab portions 22121 are bent relative to the first direction X. At least a portion of the plurality of tab portions 22121 are stacked along the first direction X, and a protrusion 22121a is formed on at least one side of the tab portion 22121 in its thickness direction.

[0146] The electrode 221 may include a main body 2211 and an electrode tab 2212 connected to one end of the main body 2211 in the first direction X. The main bodies 2211 and the separator 222 of two electrodes 221 with opposite polarities are wound along the winding direction Y to form the main body 223 of the electrode assembly 22. The winding center axis of the electrode assembly 22 extends along the first direction X, so that the electrode tab 2212 of each electrode 221 is formed at one end of the electrode assembly 22 in the first direction X, thereby making the electrode tab 2212 and the main body 223 arranged along the first direction X.

[0147] For example, in Figure 3 In the middle, two pole pieces 221 with opposite polarities each have a tab 2212. The two tabs 2212 have opposite polarities and are located at both ends of the main body 223 in the first direction X.

[0148] The main body 2211 of the electrode 221 is the region where the chemical reaction of the electrode 221 occurs within the battery cell 20. It mainly relies on the movement of metal ions between the main bodies 2211 of the two electrodes 221 with opposite polarities to function. The main body 2211 of the electrode 221 includes a substrate 22111 and an active material layer 22112 disposed on one side of the substrate 22111. The tab 2212 is connected to one end of the substrate 22111 along a first direction X. The active material layer 22112 is used to carry out chemical reactions within the battery cell 20 during use.

[0149] The tab portion 22121 is bent relative to the first direction X. That is, when the electrode sheet 221 is not wound to form the electrode assembly 22 and is in the unfolded state, the tab portion 22121 is a structure that extends along the first direction X. After the electrode sheet 221 is wound to form the electrode assembly 22, the tab portion 22121 needs to be bent so that the tab portion 22121 is set at a non-zero angle with the first direction X, so that at least a portion of the multiple tab portions 22121 can be stacked on top of each other along the first direction X to form the tab 2212.

[0150] In some embodiments, after the main body portion 2211 of the two electrode sheets 221 and the spacer 222 are wound to form the main body 223 of the electrode assembly 22, the plurality of electrode tab portions 22121 of the electrode tab 2212 can be processed by a smoothing or kneading process to bend the electrode tab portions 22121 relative to the first direction X, and to stack at least a portion of the plurality of electrode tab portions 22121 along the first direction X. It should be noted that after the electrode tab portions 22121 are bent relative to the first direction X, the thickness direction Z of the electrode tab portion can be the same as the first direction X, or it can be set at a small angle to the first direction X, for example, the angle between the thickness direction Z of the electrode tab portion and the first direction X is less than or equal to 10°. For example, in Figure 5 In the middle, the thickness direction Z of the electrode tab is the same as the first direction X. When the electrode plate 221 is unfolded, it is as follows: Figure 7 As shown, the extension direction of the main body 2211 of the electrode 221 is the winding direction Y, so that the multiple tabs 22121 of the tab 2212 are spaced apart along the extension direction of the main body 2211. At the same time, after the electrode 221 is unfolded, the first direction X, the extension direction of the main body 2211 and the thickness direction Z of the tab are mutually perpendicular. At this time, the thickness direction of the substrate 22111 is the same as the thickness direction Z of the tab.

[0151] Optionally, the substrate 22111 and the tab 2212 can be an integral structure or a separate structure. If the substrate 22111 and the tab 2212 are an integral structure, the multiple tab portions 22121 of the tab 2212 can be formed at one end of the substrate 22111 in the first direction X by means of cutting or the like. If the substrate 22111 and the tab 2212 are separate structures, the tab 2212 can be connected to one end of the substrate 22111 in the first direction X by means of welding or snap-fitting. In the embodiment where the substrate 22111 and the tab 2212 are separate structures, the material of the substrate 22111 can be the same as the material of the tab 2212 or different from the material of the tab 2212.

[0152] The tabs 2212 of the electrode 221 are components of the electrode 221 used to output or input electrical energy of the electrode 221. The tabs 2212 include a plurality of tab portions 22121 spaced apart along the winding direction Y, so that after the electrode 221 is wound to form the electrode assembly 22, the plurality of tab portions 22121 of the tabs 2212 can be processed by smoothing or kneading processes, so that the plurality of tab portions 22121 of the tabs 2212 can be stacked and formed at one end of the electrode assembly 22 in the first direction X, so that the positive or negative electrode of the electrode assembly 22 can be output or input after the tabs 2212 are connected to the current collector 23.

[0153] The tab 2212 includes a plurality of tab portions 22121 spaced apart along the winding direction Y, that is, after the electrode sheet 221 is unfolded, as shown in the figure. Figure 7 As shown, the multiple tabs 22121 of the tab 2212 are spaced apart along the extension direction of the main body 2211. When the electrode sheet 221 is wound along the winding direction Y to form the electrode assembly 22, the extension direction of the main body 2211 is the same as the winding direction Y, and the multiple tabs 22121 are spaced apart along the winding direction Y.

[0154] At least a portion of the plurality of tabs 22121 are stacked along the first direction X. That is, after the plurality of tabs 22121 of the tab 2212 are bent relative to the first direction X by a process of smoothing or kneading, a portion of the tabs 22121 may be stacked along the first direction X, or all the tabs 22121 may be stacked along the first direction X. It should be noted that after the electrode sheet 221 is wound to form a wound electrode assembly 22, the extension direction of the main body 2211 is the winding direction Y, so that the multiple tabs 22121 of the tab 2212 are arranged at intervals along the winding direction of the electrode sheet 221. Thus, when the tab 2212 is smoothed or flattened, since the multiple tabs 22121 of the tab 2212 are smoothed from the outer edge of the electrode assembly 22 towards the central axis of the electrode assembly 22, the multiple tabs 22121 of the tab 2212 are arranged in a structure in which a portion of the tabs 22121 are stacked with a portion of the tabs 22121 along the first direction X, and another portion of the tabs 22121 are stacked with another portion of the tabs 22121 along the first direction X. Of course, in some embodiments, the tab 22122 may also be a structure in which multiple tabs 22121 are stacked along the first direction X.

[0155] The tab 22121 has a protrusion 22121a formed on at least one side in its thickness direction. That is, in the thickness direction Z of the tab 22121, the tab 22121 may have a protrusion 22121a on only one side, or it may have protrusions 22121a on both sides of the tab 22121. Similarly, the number of protrusions 22121a provided on the tab 22121 may be one or more. For example, in Figure 7 and Figure 8 In the middle, along the thickness direction Z of the electrode ear portion, only one side of the electrode ear portion 22121 is provided with a protrusion 22121a, and the number of protrusions 22121a is multiple.

[0156] Optionally, the processing method for forming the protrusion 22121a on the tab 22121 can be various. For example, material can be added to one side of the tab 22121 through processes such as welding or extrusion molding to form the protrusion 22121a on one side of the tab 22121. Alternatively, the protrusion 22121a can be pressed out on one side of the tab 22121 through processes such as stamping or rolling, and a groove 22121b can be formed on the side of the tab 22121 opposite to the protrusion 22121a and corresponding to the position of the protrusion 22121a. For example, in Figure 8 In this configuration, the protrusion 22121a is formed on one side of the tab portion 22121 by means of stamping or rolling, so that the tab portion 22121 has a groove 22121b on the side opposite to the protrusion 22121a and at the position corresponding to the protrusion 22121a. Two electrode sheets 221 with opposite polarities and a separator 222 are wound along the winding direction Y to form a wound electrode assembly 22, so that the electrode assembly 22 has a main body 223 and two tabs 2212, and the tabs 2212 and the main body 223 are arranged along the first direction X. The tab 2212 is provided with a plurality of tab portions 22121 arranged at intervals along the winding direction Y, and the tab portions 22121 are bent relative to the first direction X so that at least a portion of the plurality of tab portions 22121 of the tab 2212 can be stacked along the first direction X. By providing a protrusion 22121a on at least one side of the tab portion 22121 of the tab 2212, the thickness of the plurality of tab portions 22121 stacked together is increased, and the phenomenon of local thinness of the plurality of tab portions 22121 after stacking can be alleviated, thereby improving the production quality of the tab 2212, reducing the risk of the tab 2212 being burned through during subsequent assembly and processing, thereby reducing the phenomenon of damage to the electrode assembly 22, and improving the connection stability and assembly quality between the electrode assembly 22 and other components of the battery cell 20, thereby improving the production quality and usage stability of the battery cell 20 having such an electrode assembly 22.

[0157] According to some embodiments of this application, refer to Figure 7 and Figure 8 Please refer to further details. Figure 9 and Figure 10 , Figure 9 This is a schematic diagram of the structure of the tab 22121 provided in some embodiments of this application. Figure 10 This is a front view of the tab 22121 provided in some embodiments of this application. Along the thickness direction Z of the tab 22121, a plurality of protrusions 22121a are formed on at least one side of the tab 22121.

[0158] In this embodiment, at least one side of the tab portion 22121 is provided with a plurality of protrusions 22121a, that is, in the thickness direction Z of the tab portion, the tab portion 22121 may be provided with a plurality of protrusions 22121a on only one side, or the tab portion 22121 may be provided with a plurality of protrusions 22121a on both sides.

[0159] For example, in Figure 9 and Figure 10 In the electrode tab 22121, multiple protrusions 22121a are provided on only one side. By providing multiple protrusions 22121a on only one side of the electrode tab 22121, it is beneficial to reduce the processing difficulty of providing protrusions 22121a on the electrode tab 22121, thereby improving production efficiency.

[0160] By providing a plurality of protrusions 22121a on at least one side of the tab 22121, the area with cavities between two adjacent tabs 22121 can be effectively increased after the tab 22121 is bent relative to the first direction X and the plurality of tabs 22121 are stacked along the first direction X. This is beneficial to further improve the overall thickness of the tab 2212 in the first direction X and improve the uniformity of the thickness of the tab 2212. In turn, it can further alleviate the phenomenon of the tab 2212 being burned through during subsequent assembly and processing.

[0161] According to some embodiments of this application, please continue to refer to Figure 9 and Figure 10 As shown, along the thickness direction Z of the tab, the projected area of ​​the tab 22121 is S1, and the sum of the projected areas of the multiple protrusions 22121a on the tab 22121 is S2, which satisfies that S2 / S1≥0.5.

[0162] Wherein, along the thickness direction Z of the tab, the projected area of ​​the tab 22121 is S1, that is, the area defined by the projection of the tab 22121 on the thickness direction Z of the tab is S1.

[0163] Along the thickness direction Z of the tab, the sum of the projected areas of the plurality of protrusions 22121a on the tab 22121 is S2, that is, the sum of the areas of the regions defined by the projections of each protrusion 22121a in the thickness direction Z of the tab is S2. It should be noted that if the tab 22121 has protrusions 22121a on only one side, then S2 is the sum of the projected areas of the plurality of protrusions 22121a on one side of the tab 22121 in the thickness direction Z of the tab; if the tab 22121 has a plurality of protrusions 22121a on both sides, then S2 is the sum of the projected areas of the plurality of protrusions 22121a on both sides of the tab 22121 in the thickness direction Z of the tab.

[0164] For example, the sum of the projected areas S2 of the plurality of protrusions 22121a on the tab 22121 can be 0.5 times, 0.55 times, 0.58 times, 0.6 times, 0.65 times, 0.7 times or 0.8 times the projected area S1 of the tab 22121.

[0165] It should be noted that when obtaining S1 and S2, that is, when measuring the projected area S1 of the tab 22121 and the sum of the projected areas S2 of the multiple protrusions 22121a on the tab 22121, the electrode 221 needs to be unfolded before measurement (e.g., Figure 7 As shown), S1 and S2 are obtained, namely, S1 is the projection surface of the tab 22121 on the thickness direction Z of the tab when the electrode plate 221 is in the unfolded state, and S2 is the sum of the projection areas of the multiple protrusions 22121a on the tab 22121 on the thickness direction Z of the tab when the electrode plate 221 is in the unfolded state.

[0166] By setting the sum of the projected areas of the multiple protrusions 22121a on the tab 22121 in the thickness direction Z of the tab 22121 to be greater than or equal to half of the projected area of ​​the tab 22121 in the thickness direction Z of the tab 22121, the area occupied by the multiple protrusions 22121a on the tab 22121 is half or more of the area of ​​the tab 22121. This ensures that there is a sufficient area on the tab 22121 for the protrusions 22121a, so that after the multiple tabs 22121 of the tab 2212 are stacked along the first direction X, the tab 2212 has sufficient thickness and can effectively improve the uniformity of the thickness of the tab 2212, thereby reducing the risk of the tab 2212 being soldered through during subsequent assembly.

[0167] According to some embodiments of this application, see Figure 8 and Figure 10 As shown, the tab portion 22121 includes a main body region 22121c that does not overlap with the projection of the protrusion 22121a in the thickness direction Z of the tab portion. The protrusion 22121a protrudes from the main body region 22121c along the thickness direction Z of the tab portion. The maximum dimension of the tab portion 22121 along the thickness direction Z of the tab portion is D1, and the thickness of the main body region 22121c is D2, satisfying that 2≤D1 / D2≤8.

[0168] The tab portion 22121 includes a main body region 22121c that does not overlap with the projection of the protrusion 22121a in the thickness direction Z of the tab portion. That is, the area of ​​the tab portion 22121 where the protrusion 22121a is not formed is the main body region 22121c, such that the projection of the main body region 22121c in the thickness direction Z of the tab portion does not intersect with the projection of the protrusion 22121a in the thickness direction Z of the tab portion. In other words, the protrusion 22121a protrudes from one side of the main body portion 2211 in the thickness direction Z of the tab portion.

[0169] The maximum dimension of the tab 22121 is D1, and the thickness of the main body region 22121c is D2, satisfying 2≤D1 / D2≤8. That is, the maximum thickness of the tab 22121 in its thickness direction is 2 to 8 times the wall thickness of the main body region 22121c itself. In other words, the maximum thickness of the tab 22121 after forming the protrusion 22121a through processes such as stamping or rolling is 2 to 8 times the thickness of the tab 22121 before the stamping or rolling process.

[0170] For example, the maximum size D1 of the tab 22121 can be 2 times, 2.5 times, 2.8 times, 3 times, 3.5 times, 4 times, 5 times, 6 times or 8 times the thickness D2 of the main body region 22121c.

[0171] It should be noted that if the electrode 221 is a positive electrode, then the tab 2212 corresponding to the electrode 221 is a positive tab, and the thickness of the tab portion 22121 of the positive tab before the protrusion 22121a is formed by stamping or rolling is 10μm-16μm; if the electrode 221 is a negative electrode, then the tab 2212 corresponding to the electrode 221 is a negative tab, and the thickness of the tab portion 22121 of the negative tab before the protrusion 22121a is formed by stamping or rolling is 4μm-10μm.

[0172] The tab portion 22121 has a main body region 22121c that does not overlap with the projection of the protrusion 22121a in the thickness direction Z of the tab portion, and the protrusion 22121a protrudes from the main body region 22121c in the thickness direction Z of the tab portion. That is, the main body region 22121c of the tab portion 22121 is the area of ​​the tab portion 22121 where the protrusion 22121a is not provided. This is achieved by setting the maximum dimension of the tab portion 22121 in the thickness direction Z of the tab portion to twice the thickness of the main body region 22121c. Up to 8 times, that is, the maximum thickness of the tab 22121 after the protrusion 22121a is provided is 2 to 8 times the thickness of the main body area 22121c of the tab 22121. Thus, after the tab 22121 is bent relative to the first direction X, the thickness of the multiple tabs 22121 of the tab 2212 stacked together along the first direction X can be effectively increased, thereby increasing the thickness of the tab 2212 and effectively alleviating the phenomenon of the tab 2212 being burned through during subsequent assembly.

[0173] According to some embodiments of this application, see Figure 7 , Figure 9 and Figure 10 As shown, the tab portion 22121 has multiple rows of protrusions 22121a, and each row of protrusions 22121a includes multiple protrusions 22121a spaced apart.

[0174] The tab portion 22121 has multiple rows of protrusions 22121a, each row of which includes multiple protrusions 22121a spaced apart. In other words, the multiple protrusions 22121a on the tab portion 22121 are arranged in a multi-row, multi-column configuration. Before the electrode sheet 221 is wound, i.e., in the unfolded structure of the electrode sheet 221, the multiple protrusions 22121a in each row can be spaced apart along the first direction X, or spaced apart along the winding direction Y (the extension direction of the main body portion 2211).

[0175] In the tab portion 22121 of this structure, the shape of the protrusion 22121a can be various; for example, in Figure 9 and Figure 10 In the middle, protrusion 22121a is a hemispherical structure, as shown in the reference. Figure 11 and Figure 12 As shown, Figure 11 This is a schematic diagram of the structure of the tab 22121 provided in some embodiments of this application. Figure 12 The image shows a front view of the tab 22121 provided in some embodiments of this application. The protrusion 22121a can also be a square columnar structure. Of course, the structure of the protrusion 22121a is not limited to this. In other embodiments, the protrusion 22121a can also be a cylindrical structure, a triangular columnar structure, a pentagonal columnar structure, etc.

[0176] By providing multiple rows of protrusions 22121a on the tab portion 22121, and each row of protrusions 22121a including multiple protrusions 22121a spaced apart, the multiple protrusions 22121a on the tab portion 22121 are arranged in an orderly manner. This effectively increases the area with cavities between two adjacent tab portions 22121 after the multiple tab portions 22121 of the tab 2212 are stacked along the first direction X. This is beneficial to further improve the overall thickness of the tab 2212 in the first direction X and can effectively improve the uniformity of the thickness of the tab 2212, so as to reduce the phenomenon of the tab 2212 being burned through during subsequent assembly.

[0177] In some embodiments, see Figure 10 and Figure 12 As shown, the maximum dimension of the protrusion 22121a in the direction perpendicular to the thickness direction Z of the electrode ear is W1, which satisfies 0.3mm≤W1≤2mm.

[0178] The maximum dimension of the protrusion 22121a in the direction perpendicular to the thickness direction Z of the tab is W1. That is, the maximum width of the protrusion 22121a in any direction within the plane perpendicular to the thickness direction Z of the tab is W1. In other words, the maximum radial width of the protrusion 22121a within the plane perpendicular to the thickness direction Z of the tab is W1. For example, if the protrusion 22121a is a hemispherical or cylindrical structure, then W1 is the diameter of the protrusion 22121a; if the protrusion 22121a is a square columnar structure, then W1 is the length of the diagonal of the protrusion 22121a.

[0179] For example, the maximum dimension W1 of the protrusion 22121a in the direction perpendicular to the thickness direction Z of the tab can be 0.3mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm or 2mm, etc.

[0180] By setting the maximum dimension of the protrusion 22121a in the direction perpendicular to the thickness Z of the electrode tab to be between 0.3mm and 3mm, that is, the maximum dimension of the protrusion 22121a in its radial direction is between 0.3mm and 3mm, on the one hand, the phenomenon that the processing difficulty is too high due to the small size of the protrusion 22121a can be alleviated, thereby reducing the processing difficulty of the electrode tab 22121. On the other hand, the phenomenon that the number of protrusions 22121a on the electrode tab 22121 is limited due to the large size of the protrusion 22121a can also be alleviated. Furthermore, in embodiments where a groove 22121b is provided on the side of the tab 22121 opposite to the protrusion 22121a and corresponding to the position of the protrusion 22121a, this structure can effectively alleviate the phenomenon that the protrusions 22121a and grooves 22121b of two adjacent tabs 22121 overlap and cancel each other out due to the excessive size of the protrusion 22121a. This results in a cavity between two adjacent tabs 22121 that are stacked together, thereby increasing the overall thickness of the tab 2212.

[0181] According to some embodiments of this application, refer to Figure 13 and Figure 14 , Figure 13 This is a schematic diagram of the structure of the tab 22121 provided in some embodiments of this application. Figure 14 The image shows a front view of a tab 22121 provided in some embodiments of this application. The tab 22121 has a plurality of protrusions 22121a arranged at intervals, and the two ends of the protrusions 22121a extend to the two ends of the tab 22121 in a direction perpendicular to the arrangement direction of the plurality of protrusions 22121a.

[0182] The arrangement direction of the multiple protrusions 22121a refers to the direction in which the multiple protrusions 22121a are arranged sequentially at intervals in a plane perpendicular to the thickness direction Z of the tab.

[0183] The two ends of the protrusion 22121a extend to the two ends of the tab 22121 in a direction perpendicular to the arrangement direction of the plurality of protrusions 22121a. That is, the protrusion 22121a is a strip structure, and the two ends of the protrusion 22121a extend to the two ends of the tab 22121 in a direction perpendicular to the arrangement direction of the plurality of protrusions 22121a, so that the plurality of protrusions 22121a are arranged at intervals along the width direction of the protrusions 22121a. It should be noted that when the electrode 221 is in the unfolded state, the extension direction of the strip structure protrusion 22121a can be along the first direction X or along the winding direction Y (the extension direction of the main body 2211).

[0184] For example, in Figure 13 and Figure 14In the figure, the protrusion 22121a is a strip structure with a rectangular cross-section. Of course, in other embodiments, the protrusion 22121a can also be a strip structure with a semi-circular, pentagonal or other cross-sections.

[0185] By forming a plurality of protrusions 22121a spaced apart on the tab portion 22121, and having both ends of the protrusions 22121a extending to both ends of the tab portion 22121, a structure is achieved in which a plurality of protrusions 22121a are provided on the tab portion 22121. This structure helps to reduce the difficulty of providing protrusions 22121a on the tab portion 22121, thereby improving the processing efficiency of the tab portion 22121.

[0186] In some embodiments, see Figure 14 As shown, along the arrangement direction of the multiple protrusions 22121a, the width of the protrusion 22121a is W2, which satisfies 0.3mm≤W2≤2mm.

[0187] Among them, the width of the protrusion 22121a is W2, that is, in the arrangement direction of the multiple protrusions 22121a, the maximum size of the protrusion 22121a is W2.

[0188] For example, the width W2 of the protrusion 22121a can be 0.3mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm or 2mm, etc.

[0189] By setting the width of the protrusion 22121a in the arrangement direction of the multiple protrusions 22121a to 0.3mm to 3mm, that is, the dimension of the protrusion 22121a in the direction perpendicular to the extension direction of the protrusion 22121a is 0.3mm to 3mm, on the one hand, it can alleviate the phenomenon that the processing difficulty is too high due to the excessive width of the protrusion 22121a, thereby reducing the processing difficulty of the tab 22121, and on the other hand, it can alleviate the phenomenon that the number of multiple protrusions 22121a on the tab 22121 is limited due to the excessive width of the protrusion 22121a. Furthermore, in the embodiment where a groove 22121b is provided on the side of the tab 22121 away from the protrusion 22121a and at the position corresponding to the protrusion 22121a, this structure can effectively alleviate the phenomenon that the protrusions 22121a and grooves 22121b of two adjacent tabs 22121 overlap and cancel each other out due to the excessive width of the protrusion 22121a. This results in a cavity between two adjacent tabs 22121 that are stacked together, so as to meet the requirement that the flattened tab 2212 has sufficient thickness.

[0190] According to some embodiments of this application, refer to Figure 15 and Figure 16 , Figure 15A partial cross-sectional view of the electrode 221 provided in other embodiments of this application after being unfolded. Figure 16 This is a cross-sectional view of the tab portion 22121 of the electrode sheet 221 provided in some other embodiments of this application. Along the thickness direction Z of the tab portion, the tab portion 22121 may include a plurality of foils 22121d stacked together. A protrusion 22121e is formed on one side of each foil 22121d, and a recess 22121f is formed on the other side at a position corresponding to the protrusion 22121e. In two adjacent foils 22121d, the protrusion 22121e of one foil 22121d is accommodated in the recess 22121f of the other foil 22121d. Along the thickness direction Z of the tab portion, the protrusion 22121e located on one side of the tab portion 22121 is a protrusion 22121a.

[0191] Along the thickness direction Z of the tab portion, the tab portion 22121 includes a plurality of foils 22121d stacked together, that is, the tab portion 22121 is composed of a plurality of foils 22121d, and the plurality of foils 22121d are stacked along the thickness direction Z of the tab portion to form the tab portion 22121 of the tab 2212. For example, in... Figure 15 and Figure 16 In this embodiment, the tab portion 22121 may include two foils 22121d. One of the foils 22121d is connected to the main body portion 2211, and the other foil 22121d is stacked along the thickness direction Z of the tab portion on one side of the foil 22121d connected to the main body portion 2211. Of course, in other embodiments, the tab portion 22121 may be formed by stacking three, four, five, or six foils 22121d. It should be noted that in some embodiments, the tab portion 22121 may also include only one foil 22121d.

[0192] A protrusion 22121e is formed on one side of the foil 22121d, and a recess 22121f is formed on the other side at the position corresponding to the protrusion 22121e. That is, in the thickness direction Z of the tab, a protrusion 22121e protruding from the foil 22121d is formed on one side of the foil 22121d, and a recess 22121f is formed on the other side at the position corresponding to the protrusion 22121e, so that the protrusion 22121e and the recess 22121f are arranged one-to-one in the thickness direction Z of the tab.

[0193] In two adjacent foils 22121d, the protrusion 22121e of one foil 22121d is accommodated in the recess 22121f of the other foil 22121d. That is, along the thickness direction Z of the tab, in two stacked and adjacent foils 22121d, the protrusion 22121e of one foil 22121d is correspondingly arranged with the groove 22121b of the other foil 22121d, so that the protrusion 22121e of one foil 22121d can be embedded in the groove 22121b of the other foil 22121d, so that the two foils 22121d can be tightly attached.

[0194] Along the thickness direction Z of the tab portion, the protrusion 22121e on one side of the tab portion 22121 is a protrusion 22121a. That is to say, the protrusion 22121e of the foil 22121d on one side of the multiple foils 22121d of the tab portion 22121 is the protrusion 22121a on one side of the tab portion 22121. Correspondingly, the concave portion 22121f of the foil 22121d on the other side of the multiple foils 22121d of the tab portion 22121 is the groove 22121b on the other side of the tab portion 22121.

[0195] For example, the connection method between the multiple foils 22121d of the tab 22121 can be various, such as snap-fit, bonding or welding.

[0196] By configuring the tab 22121 as a structure in which multiple foils 22121d are stacked, and a protrusion 22121e is formed on one side of the foil 22121d and a recess 22121f is formed on the other side, the protrusions 22121e and recesses 22121f of two adjacent foils 22121d can be interlocked after the multiple foils 22121d are stacked, so that a protrusion 22121a is formed on one side of the tab 22121 in the thickness direction Z. The tab 22121 with this structure can effectively increase the thickness and structural strength of the tab 22121 itself. Thus, after the multiple tabs 22121 of the tab 2212 are stacked along the first direction X, the overall thickness and structural strength of the tab 2212 can be further increased, so as to further reduce the risk of the tab 2212 being soldered through during subsequent assembly.

[0197] According to some embodiments of this application, see Figure 16As shown, multiple foils 22121d are welded together to form protrusions 22121e and recesses 22121f on the foils 22121d. That is, during the welding process, protrusions 22121e and recesses 22121f are formed at the welding positions of the multiple foils 22121d, meaning that the protrusions 22121e and recesses 22121f on the foils 22121d are structures formed by welding multiple foils 22121d.

[0198] For example, multiple foils 22121d are joined by ultrasonic roll welding to form protrusions 22121e and recesses 22121f at the welding locations of the foils 22121d. Specific connection methods for ultrasonic roll welding can be found in related technologies and will not be elaborated here.

[0199] Multiple foils 22121d stacked together are connected by welding. Protrusions 22121e and concave portions 22121f are formed at the welding points of the multiple foils 22121d. This method helps to improve the connection strength and stability between the multiple foils 22121d and reduces the processing difficulty of forming concave portions 22121f and protrusions 22121e on the foils 22121d. This optimizes the production cycle of the electrode 221 and effectively improves the production efficiency of the electrode 221.

[0200] According to some embodiments of this application, see Figure 5 , Figure 15 and Figure 16 As shown, the electrode 221 may include a main body 2211, a plurality of tabs 22121 connected to the main body 2211, and the main bodies 2211 and the spacer 222 of the two electrodes 221 are wound along the winding direction Y to form a main body 223. The main body 2211 includes a substrate 22111 and an active material layer 22112 disposed on at least one side of the substrate 22111. The plurality of foils 22121d may include a first foil 22121g and a second foil 22121h stacked together. The first foil 22121g is connected to one end of the substrate 22111 in the first direction X and is integrally formed with the substrate 22111, while the second foil 22121h is separately disposed from the substrate 22111.

[0201] In this embodiment, multiple tabs 22121 of the tab 2212 are connected to one end of the main body 2211 in the first direction X. When the electrode 221 is in the unfolded state, the tabs 2212 and the main body 2211 are arranged along the first direction X, and the multiple tabs 22121 of the tab 2212 are spaced apart along the extension direction of the main body 2211. After the electrode 221 is wound to form the electrode assembly 22 and the tabs 22121 are bent relative to the first direction X, the multiple tabs 22121 of the tab 2212 are spaced apart along the winding direction Y. The tabs 22121 are connected to one end of the main body 2211 in the first direction X and are arranged at a non-zero angle with the main body 2211.

[0202] An active material layer 22112 is provided on at least one side of the substrate 22111. That is, the substrate 22111 may have an active material layer 22112 provided on only one side, or the substrate 22111 may have an active material layer 22112 provided on both sides. For example, in Figure 15 In the substrate 22111, active material layers 22112 are provided on both sides.

[0203] The active material layer 22112 is the region within the battery cell 20 where chemical reactions occur, primarily functioning by the movement of metal ions between the active material layers 22112 of the two electrodes 221. In some embodiments, an insulating protective layer may also be coated on the substrate 22111, disposed along the first direction X at one or both ends of the active material layer 22112 to protect and separate it. In other embodiments, the end of the active material layer 22112 in the first direction X may not have an insulating protective layer, meaning the substrate 22111 may only have the active material layer 22112 coated on it.

[0204] It should be noted that if the electrode 221 is a positive electrode, the active material layer 22112 of the main body 2211 corresponding to the electrode 221 can be made of lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide, etc.; if the electrode 221 is a negative electrode, the active material layer 22112 of the main body 2211 corresponding to the electrode 221 can be made of carbon or silicon, etc.

[0205] The first foil 22121g is connected to one end of the substrate 22111 in the first direction X and is integrally formed with the substrate 22111, that is, the first foil 22121g is connected to the substrate 22111, and the first foil 22121g is a structure formed on the substrate 22111 by cutting and processing. Of course, in other embodiments, the first foil 22121g and the substrate 22111 can also be separate structures. For example, the first foil 22121g is connected to one end of the substrate 22111 in the first direction X by welding or other means. Similarly, the first foil 22121g and the substrate 22111 can also be indirectly connected. For example, the first foil 22121g and the substrate 22111 are indirectly connected through other conductive components.

[0206] For example, one end of the first foil 22121g in the direction perpendicular to the thickness direction Z of the tab is connected to one end of the substrate 22111 in the first direction X.

[0207] It should be noted that after the electrode sheet 221 is unfolded, the thickness direction Z of the electrode tab is perpendicular to the first direction X. Therefore, the end of the first foil 22121g perpendicular to the thickness direction Z of the electrode tab is connected to the end of the substrate 22111 in the first direction X. This means that the end of the first foil 22121g in the first direction X is connected to the end of the substrate 22111 in the first direction X (see [reference]). Figure 15 (As shown).

[0208] The second foil 22121h and the substrate 22111 are separately disposed, that is, the second foil 22121h and the substrate 22111 are two independent components. For example, in... Figure 15 In this embodiment, the second foil 22121h is stacked and connected to the first foil 22121g on one side of the thickness direction Z of the tab portion. It should be noted that in other embodiments, the first foil 22121g may have the second foil 22121h only on one side of the tab portion, or it may have the second foil 22121h on both sides. Furthermore, the number of second foils 22121h on one side of the first foil 22121g may be one or more.

[0209] The plurality of foils 22121d includes a first foil 22121g integrally formed with the substrate 22111 of the main body 2211 of the electrode 221. In actual production, an area without an active material layer 22112 can be reserved on the substrate 22111, so that the first foil 22121g can be set in this area. Then, the second foil 22121h can be stacked on one side of the first foil 22121g, so that the first foil 22121g can provide a connection support point for the second foil 22121h, thereby improving the thickness and structural strength of the tab 22121. The electrode 221 with this structure can effectively reduce the process difficulty of connecting the tab 22121 to the substrate 22111, which is conducive to improving the production efficiency of the electrode assembly 22.

[0210] According to some embodiments of this application, see Figure 5 and Figure 15 As shown, the substrate 22111 includes a coating area 22111a and a spacer area 22111b. The coating area 22111a and the spacer area 22111b are arranged along the first direction X. The active material layer 22112 is disposed in the coating area 22111a. The spacer area 22111b connects the coating area 22111a and the first foil 22121g.

[0211] The spacer region 22111b of the substrate 22111 is the area on the substrate 22111 that is not coated with the active material layer 22112. The coating region 22111a and the spacer region 22111b are arranged along the first direction X, and the spacer region 22111b connects the coating region 22111a and the first foil 22121g. That is, when the electrode 221 is unfolded, the spacer region 22111b connects the coating region 22111a and the first foil 22121g in the first direction X.

[0212] exist Figure 15 In this context, the spacer region 22111b is a blank area on the substrate 22111. It should be noted that in some embodiments, the spacer region 22111b on the substrate 22111, where the active material layer 22112 is not coated, can also be coated with an insulating protective layer to protect the active material layer 22112. Of course, in other embodiments, the substrate 22111 of the main body 2211 may not have a spacer region 22111b, that is, the first foil 22121g is directly connected to the coating area 22111a of the substrate 22111. In other words, the active material layer 22112 completely covers one side of the substrate 22111, so that the first foil 22121g is connected to one end of the substrate 22111.

[0213] By providing a coating area 22111a coated with an active material layer 22112 and a spacer area 22111b uncoated with an active material layer 22112 on a substrate 22111, the first foil 22121g of the tab 22121 can be connected to the coating area 22111a through the spacer area 22111b. This allows the tab 22121 and the active material layer 22112 to be spaced apart in the first direction X. With this structure, the electrode assembly 22 can, on the one hand, use the spacer area 22111b to isolate the stress generated during the bending process of the tab 22121 relative to the first direction X, thereby reducing the risk of breakage of the active material layer 22112 on the coating area 22111a. On the other hand, it can reduce the impact on the active material layer 22112 during the subsequent welding of the tab 2212 to other components, thereby mitigating the damage to the active material layer 22112 and improving the production quality of the electrode assembly 22.

[0214] According to some embodiments of this application, see Figure 16 As shown, along the thickness direction Z of the tab, the thickness of the first foil 22121g is D3, and the thickness of the second foil 22121h is D4, satisfying 0.5≤D3 / D4≤2.

[0215] Wherein, the thickness D3 of the first foil 22121g is the wall thickness of the first foil 22121g itself, that is, the thickness D3 of the first foil 22121g is the thickness of the area of ​​the first foil 22121g before the protrusions 22121e and the concave portions 22121f are formed, that is, the thickness D3 of the first foil 22121g is the thickness of the first foil 22121g before the protrusions 22121e and the concave portions 22121f are formed.

[0216] The thickness D4 of the second foil 22121h is the wall thickness of the second foil 22121h itself. That is, the thickness D4 of the second foil 22121h is the thickness of the area of ​​the first foil 22121g where the protrusions 22121e and the recesses 22121f are not formed. In other words, the thickness D4 of the second foil 22121h is the thickness of the second foil 22121h before the protrusions 22121e and the recesses 22121f are formed.

[0217] For example, the thickness D3 of the first foil 22121g can be 0.5 times, 0.6 times, 0.75 times, 0.8 times, 1 time, 1.2 times, 1.5 times or 2 times the thickness D4 of the second foil 22121h.

[0218] In the experiment, a first foil 22121g with a thickness of 12μm was selected, and the thickness of the second foil 22121h was set to different values ​​to measure the effect of the thickness ratio of the first foil 22121g to the second foil 22121h on the welding assembly of the two foils under different conditions. The experimental results are as follows:

[0219]

[0220] The experimental data above shows that when the ratio of the thickness D3 of the first foil 22121g to the thickness D4 of the second foil 22121h is greater than 2, the second foil 22121h will experience weld cracking during the welding process, resulting in debris. This fails to meet the requirements for welding and assembling the first foil 22121g and the second foil 22121h together. When the ratio of the thickness D3 of the first foil 22121g to the thickness D4 of the second foil 22121h is less than or equal to 2, neither the first foil 22121g nor the second foil 22121h experiences weld cracking during the welding process. Therefore, the ratio of the thickness D3 of the first foil 22121g to the thickness D4 of the second foil 22121h is set to be less than or equal to 2.

[0221] Similarly, when the ratio of the thickness D3 of the first foil 22121g to the thickness D4 of the second foil 22121h is less than 0.5, the first foil 22121g will experience weld cracking during the welding process, resulting in debris. This fails to meet the requirements for welding and assembling the first foil 22121g and the second foil 22121h together. When the ratio of the thickness D3 of the first foil 22121g to the thickness D4 of the second foil 22121h is greater than or equal to 0.5, neither the first foil 22121g nor the second foil 22121h experiences weld cracking during the welding process. Therefore, the ratio of the thickness D3 of the first foil 22121g to the thickness D4 of the second foil 22121h is set to be greater than or equal to 0.5.

[0222] By setting the thickness of the first foil 22121g to 0.5 to 2 times the thickness of the second foil 22121h (i.e., the thickness of the first foil 22121g is 0.5 to 2 times the thickness of the second foil 22121h), the problem of excessive assembly difficulty in connecting the first foil 22121g and the second foil 22121h due to a large difference in thickness between them can be alleviated, thereby reducing the processing difficulty of the tab 22121 in this structure. Furthermore, this approach alleviates both the problem of damage to the second foil 22121h during welding when the thickness of the first foil 22121g is significantly greater than that of the second foil 22121h, and the problem of damage to the first foil 22121g during welding when the thickness of the second foil 22121h is significantly greater than that of the first foil 22121g.

[0223] According to some embodiments of this application, please refer to Figure 15 and Figure 16 As shown, along the Z direction perpendicular to the thickness of the electrode tab, the end of the second foil 22121h near the substrate 22111 does not extend beyond the first foil 22121g and is connected to one end of the substrate 22111. It should be noted that when the electrode 221 is in the unfolded state, the end of the second foil 22121h near the substrate 22111 does not extend beyond the first foil 22121g and is connected to one end of the substrate 22111 in the first X direction.

[0224] Wherein, the end of the second foil 22121h closest to the substrate 22111 does not extend beyond the end of the first foil 22121g connected to the substrate 22111. That is, the end of the first foil 22121g connected to the substrate 22111 can be flush with the second foil 22121h, or it can extend beyond the second foil 22121h. For example, in Figure 15 and Figure 16 In the first foil 22121g is connected to one end of the substrate 22111 and extends to the other end of the second foil 22121h, which is close to the substrate 22111.

[0225] It should be noted that when the electrode 221 is in the unfolded state, the end of the second foil 22121h near the substrate 22111 in the first direction X does not extend beyond the end of the first foil 22121g connected to the substrate 22111 in the first direction X. If the electrode 221 is wound to form the electrode assembly 22, and the multiple tab portions 22121 of the electrode tabs are flattened or kneaded and stacked on one end of the electrode assembly 22, then the direction of the second foil 22121h perpendicular to the first direction X along the end of the first foil 22121g away from the substrate 22111, pointing towards the end of the first foil 22121g connected to the substrate 22111, does not extend beyond the end of the first foil 22121g connected to the substrate 22111.

[0226] By setting the second foil 22121h in the direction perpendicular to the thickness direction Z of the tab portion to not exceed one end of the first foil 22121g connected to the substrate 22111, the interference between the second foil 22121h and the active material layer 22112 disposed on one side of the substrate 22111 can be effectively mitigated, thereby reducing the risk of the active material layer 22112 being damaged by the second foil 22121h.

[0227] According to some embodiments of this application, please continue to refer to Figure 15 and Figure 16 As shown, along the Z direction perpendicular to the thickness of the electrode tab, the distance L between the end of the first foil 22121g away from the substrate 22111 and the end of the second foil 22121h away from the substrate 22111 is satisfied, where L ≤ 2mm. It should be noted that when the electrode 221 is in the unfolded state, L is the distance along the first direction X between the end of the first foil 22121g away from the substrate 22111 and the end of the second foil 22121h away from the substrate 22111.

[0228] Wherein, the distance between the end of the first foil 22121g away from the substrate 22111 and the end of the second foil 22121h away from the substrate 22111 is L, that is, the end of the first foil 22121g away from the substrate 22111 and the end of the second foil 22121h away from the substrate 22111 can be flush with each other or staggered. If the end of the first foil 22121g away from the substrate 22111 and the end of the second foil 22121h away from the substrate 22111 are staggered, then the distance between the end of the first foil 22121g away from the substrate 22111 and the end of the second foil 22121h away from the substrate 22111 is less than or equal to 2mm.

[0229] It should be noted that the distance L between the end of the first foil 22121g furthest from the substrate 22111 and the end of the second foil 22121h furthest from the substrate 22111 can be either the end of the first foil 22121g furthest from the substrate 22111 extending beyond the end of the second foil 22121h furthest from the substrate 22111, and the dimension of the first foil 22121g extending beyond the second foil 22121h is less than or equal to 2 mm; or the end of the second foil 22121h furthest from the substrate 22111 extending beyond the end of the first foil 22121g furthest from the substrate 22111, and the dimension of the second foil 22121h extending beyond the first foil 22121g is less than or equal to 2 mm. Similarly, L can be 0 mm, 0.2 mm, 0.5 mm, 1 mm, 1.5 mm, or 2 mm, etc.

[0230] For example, in Figure 16 In the first foil 22121g, the end of the first foil 22121g that is away from the substrate 22111 extends beyond the end of the second foil 22121h that is away from the substrate 22111, and the size of the portion of the first foil 22121g that extends beyond the second foil 22121h is L.

[0231] By setting the distance between the end of the first foil 22121g away from the substrate 22111 and the end of the second foil 22121h away from the substrate 22111 in the direction perpendicular to the thickness direction Z of the tab portion to be less than or equal to 2 mm, that is, the dimension by which the end of the first foil 22121g away from the substrate 22111 extends beyond the end of the second foil 22121h away from the substrate 22111 is less than or equal to 2 mm, or the dimension by which the end of the second foil 22121h away from the substrate 22111 extends beyond the first foil 22121g away from the substrate 22111 is less than or equal to 2 mm. The dimension of the end of the foil 22121g away from the substrate 22111 is less than or equal to 2mm. This can alleviate the phenomenon that the first foil 22121g exceeds the second foil 22121h by too much or the second foil 22121h exceeds the first foil by too much, which would result in the tab 22121 being excessively long or inserted into the electrode assembly 22. This is beneficial to improving the production quality and reliability of the electrode assembly 22.

[0232] In some embodiments, the first foil 22121g and the second foil 22121h are made of the same material. That is, the first foil 22121g and the second foil 22121h are both made of the same material.

[0233] For example, the materials of the first foil 22121g and the second foil 22121h can be various, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0234] By setting the first foil 22121g and the second foil 22121h to the same material, the polarity of the tab 22121 can be stabilized, and the process difficulty of connecting the first foil 22121g and the second foil 22121h can be reduced.

[0235] According to some embodiments of this application, see Figure 5 , Figure 7 and Figure 8 As shown, the electrode 221 may include a main body 2211, and a plurality of tabs 22121 connected to one end of the main body 2211 in a first direction X. The main bodies 2211 and the spacer 222 of the two electrodes 221 are wound along the winding direction Y to form a main body 223. The main body 2211 includes a substrate 22111 and an active material layer 22112 disposed on at least one side of the substrate 22111. The substrate 22111 includes a coating area 22111a and a spacer area 22111b. The coating area 22111a and the spacer area 22111b are arranged along the first direction X. The active material layer 22112 is disposed in the coating area 22111a. The spacer area 22111b connects the coating area 22111a and the tabs 22121.

[0236] In this embodiment, multiple tabs 22121 of the tab 2212 are connected to one end of the main body 2211 in the first direction X. When the electrode 221 is in the unfolded state, the tabs 2212 and the main body 2211 are arranged along the first direction X, and the multiple tabs 22121 of the tab 2212 are spaced apart along the extension direction of the main body 2211. After the electrode 221 is wound to form the electrode assembly 22 and the tabs 22121 are bent relative to the first direction X, the multiple tabs 22121 of the tab 2212 are spaced apart along the winding direction Y. The tabs 22121 are connected to one end of the main body 2211 in the first direction X and are arranged at a non-zero angle with the main body 2211.

[0237] An active material layer 22112 is provided on at least one side of the substrate 22111; that is, the substrate 22111 may have an active material layer 22112 provided on one side, or it may have an active material layer 22112 provided on both sides. For example, in... Figure 8 In the substrate 22111, active material layers 22112 are provided on both sides.

[0238] The spacer region 22111b of the substrate 22111 is the area on the substrate 22111 that is not coated with the active material layer 22112. The coating region 22111a and the spacer region 22111b are arranged along the first direction X, and the spacer region 22111b connects the coating region 22111a and the tab 22121. That is, in the first direction X, the spacer region 22111b connects the coating region 22111a and the tab 22121. It should be noted that in this embodiment, the tab 22121 may be a structure that includes only one foil 22121d, or the tab 22121 may be a structure that includes multiple foils 22121d stacked together.

[0239] exist Figure 8 In this context, the spacer region 22111b is a blank area on the substrate 22111. It should be noted that in some embodiments, the spacer region 22111b on the substrate 22111, where the active material layer 22112 is not coated, may also be coated with an insulating protective layer to protect the active material layer 22112. Of course, in other embodiments, the spacer region 22111b may not be provided on the substrate 22111 of the main body 2211, that is, the tab 22121 is directly connected to the coated area 22111a of the substrate 22111. In other words, the active material layer 22112 completely covers one side of the substrate 22111, so that the tab 22121 is connected to one end of the substrate 22111.

[0240] By providing a coating area 22111a coated with an active material layer 22112 and a spacer area 22111b without an active material layer 22112 on a substrate 22111, the tab 22121 can be connected to the coating area 22111a through the spacer area 22111b. This allows the tab 22121 and the active material layer 22112 to be spaced apart in the first direction X. With this structure, the electrode assembly 22 can, on the one hand, isolate the stress generated during bending of the tab 22121 relative to the first direction X through the spacer area 22111b, thereby reducing the risk of breakage of the active material layer 22112 on the coating area 22111a. On the other hand, it can reduce the impact on the active material layer 22112 during subsequent welding of the tab 2212 to other components, thereby mitigating the damage to the active material layer 22112 and improving the production quality of the electrode assembly 22.

[0241] In some embodiments, see Figure 5 As shown, the tab portion 22121 and the spacer region 22111b are integrally formed.

[0242] In this embodiment, the tab portion 22121 and the spacer region 22111b are integrally formed, meaning that the tab portion 22121 includes only one foil 22121d, and the tab portion 22121 is a structure formed on the substrate 22111 by cutting and processing. Of course, in other embodiments, the tab portion 22121 and the substrate 22111 can also be a separate structure. For example, the tab portion 22121 can be connected to one end of the substrate 22111 in the first direction X by welding or other means.

[0243] It should be noted that in embodiments where no spacer area 22111b is provided on the substrate 22111 of the main body 2211, the tab 22121 may also be integrally formed with the substrate 22111, that is, the tab 22121 is integrally formed with the coating area 22111a of the substrate 22111.

[0244] By setting the tab 22121 as an integrally formed structure with the spacer region 22111b of the substrate 22111, the tab 22121 can be a part of the substrate 22111 in the actual production process. The tab 22121 can be set in the area where the active material layer 22112 is not set on the substrate 22111 after reserving the area. This reduces the process difficulty of connecting the tab 22121 to the substrate 22111 and helps to improve the production efficiency of the electrode assembly 22.

[0245] According to some embodiments of this application, see Figure 5 and Figure 8 As shown, along the thickness direction Z of the tab portion, the tab portion 22121 has a groove 22121b formed on the side opposite to the protrusion 22121a and corresponding to the position of the protrusion 22121a.

[0246] Along the thickness direction Z of the tab portion, a groove 22121b is formed on the side of the tab portion 22121 away from the protrusion 22121a and corresponding to the position of the protrusion 22121a. That is, a protrusion 22121a is formed on one side of the tab portion 22121, and a groove 22121b is formed on the other side corresponding to the position of the protrusion 22121a, so that the protrusion 22121a and the groove 22121b are set in a one-to-one correspondence in the thickness direction Z of the tab portion.

[0247] For example, the electrode tab 22121 of this structure can be processed in various ways, such as stamping or rolling.

[0248] By providing a groove 22121b on the side of the tab 22121 opposite to the protrusion 22121a and corresponding to the position of the protrusion 22121a, the tab 22121 of this structure can achieve the formation of the protrusion 22121a on the tab 22121 through processes such as stamping or rolling. On the one hand, it helps to reduce the processing difficulty of the tab 22121 and improve the processing efficiency of the tab 22121. On the other hand, it eliminates the need to add material to provide the protrusion 22121a on one side of the tab 22121, thereby reducing the production cost of the tab 22121 and reducing the weight of the tab 22121.

[0249] According to some embodiments of this application, refer to 5 and Figure 8 Please refer to further details. Figure 17 , Figure 17 This is a cross-sectional view of multiple tabs 22121 of the electrode assembly 22 provided in some embodiments of this application after being stacked. Along the first direction X, in two adjacent tabs 22121, the protrusion 22121a of one tab 22121 is misaligned with the groove 22121b of the other tab 22121.

[0250] In particular, in two adjacent tabs 22121, the protrusion 22121a of one tab 22121 is misaligned with the groove 22121b of the other tab 22121, that is, in two adjacent tabs 22121, the protrusion 22121a of one tab 22121 and the groove 22121b of the other tab 22121 are not aligned in the first direction X.

[0251] By setting the protrusion 22121a of one electrode 22121 and the groove 22121b of the other electrode 22121 in the first direction X as a mutually staggered structure, the phenomenon of mutual cancellation after the protrusion 22121a and the groove 22121b overlap can be effectively alleviated, so that the electrode 2212 has sufficient thickness in the first direction X, which helps to reduce the risk of the electrode 2212 of the electrode assembly 22 being soldered through during subsequent assembly.

[0252] In some embodiments, see Figure 17 As shown, along the first direction X, the thickness of the tab 2212 is D5, which satisfies 0.2mm≤D5≤2.5mm.

[0253] The thickness of the tab 2212 is D5, which means that after the multiple tab portions 22121 of the tab 2212 are bent relative to the first direction X by a process of smoothing or kneading and stacked on one end of the body 223 of the electrode assembly 22 in the first direction X, the size of the tab 2212 in the first direction X is D5.

[0254] For example, the thickness D5 of the tab 2212 can be 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.8mm, 1mm, 1.5mm, 2mm or 2.5mm, etc.

[0255] By setting the thickness of the tab 2212 in the first direction X to between 0.2 mm and 2.5 mm, on the one hand, the risk of the tab 2212 being soldered through due to its small thickness can be mitigated, thereby reducing the risk of damage to the electrode assembly 22 during subsequent assembly. On the other hand, the phenomenon of the tab 2212 occupying too much space due to its large thickness can be mitigated, thereby optimizing the internal space of the battery cell 20 with this electrode assembly 22 and improving the energy density of the battery cell 20.

[0256] According to some embodiments of this application, see Figure 4 , Figure 5 and Figure 6 As shown, along the first direction X, two tabs 2212 are respectively disposed at both ends of the main body 223 of the electrode assembly 22.

[0257] Among them, the two electrodes 221 have opposite polarities, that is, the two electrodes 221 are the positive electrode and the negative electrode of the electrode assembly 22, respectively.

[0258] Two tabs 2212 are respectively disposed at both ends of the main body 223 of the electrode assembly 22, that is, the tabs 2212 of the two electrodes 221 with opposite polarities are respectively formed at both ends of the electrode assembly 22 in the first direction X, so that the two ends of the electrode assembly 22 in the first direction X respectively form positive tabs and negative tabs, so as to output or input the positive and negative electrodes of the electrode assembly 22.

[0259] By disposing the two tabs 2212 of the electrode assembly 22 at both ends of the body 223 of the electrode assembly 22 in the first direction X, the two tabs 2212 are respectively formed at both ends of the electrode assembly 22 in the first direction X, which facilitates the subsequent assembly of the electrode assembly 22, reduces the assembly difficulty of the battery cell 20 with such electrode assembly 22, and reduces the interference or mutual contact between the two tabs 2212, thereby reducing the risk of short circuit of the electrode assembly 22.

[0260] In some embodiments, see Figure 3 , Figure 4 and Figure 5 As shown, the main body 223 of the electrode assembly 22 is cylindrical. Of course, the structure of the main body 223 of the electrode assembly 22 is not limited to this. In other embodiments, the main body 223 of the electrode assembly 22 can also be a cylindrical structure with an elliptical cross-section.

[0261] By setting the electrode assembly 22 into a cylindrical structure, it is easier to form the battery cell 20 with a cylindrical structure in subsequent processing.

[0262] According to some embodiments of this application, see Figure 3 As shown, this application embodiment also provides a battery cell 20, including a housing 21 and an electrode assembly 22 of any of the above schemes, the electrode assembly 22 being housed within the housing 21.

[0263] The outer casing 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 closes the opening 2111 of the housing 211 to form a sealed space for accommodating the electrode assembly 22.

[0264] The housing 211 can be of various shapes, such as a cylinder, a cuboid, etc. The shape of the housing 211 can be determined according to the specific shape of the electrode assembly 22. For example, in... Figure 3 In the middle, the electrode assembly 22 is cylindrical, and correspondingly, it can be a cylindrical structure.

[0265] In some embodiments, the housing 21 may further include a positive electrode terminal and a negative electrode terminal, with the positive electrode terminal mounted on the end cap 212 and the negative electrode terminal mounted on the end of the housing 211 opposite to the end cap 212. Of course, in other embodiments, the positive electrode terminal may be mounted on the end of the housing 211 opposite to the end cap 212, and the negative electrode terminal may be mounted on the end cap 212.

[0266] The positive electrode terminal and the negative electrode terminal are respectively used to electrically connect to the tabs 2212 at both ends of the electrode assembly 22 in the first direction X, so as to output or input the electrical energy of the battery cell 20. For example, the positive electrode terminal and the negative electrode terminal can be made of various materials, such as copper, iron, aluminum, steel or aluminum alloy.

[0267] The positive electrode terminal and the negative electrode terminal can be directly connected to the tab 2212 of the electrode assembly 22, such as by welding or contact. Alternatively, the positive electrode terminal and the negative electrode terminal can be indirectly connected to the tab 2212 of the electrode assembly 22, such as by contacting or welding the positive electrode terminal and the negative electrode terminal to the electrode assembly 22 through other components.

[0268] According to some embodiments of this application, please continue to refer to Figure 3 As shown, the battery cell 20 may also include a current collector 23, which is disposed between the housing 21 and the tab 2212 along the first direction X, and the current collector 23 connects the housing 21 and the tab 2212.

[0269] The current collector 23 serves to connect the tab 2212 of the electrode assembly 22 to the positive electrode terminal or the negative electrode terminal, so as to realize the electrical connection between the electrode assembly 22 and the positive electrode terminal or the negative electrode terminal. The current collector 23 can be made of various materials, such as copper, iron, aluminum, steel or aluminum alloy.

[0270] For example, in Figure 3 In the battery cell 20, there are two current collectors 23. The two current collectors 23 are respectively disposed at both ends of the electrode assembly 22 in the first direction X. One current collector 23 is connected to the positive electrode terminal and one tab 2212 of the electrode assembly 22, and the other current collector 23 is connected to the negative electrode terminal and the other tab 2212 of the electrode assembly 22, so as to realize the input or output of electrical energy of the battery cell 20.

[0271] Optionally, the connection method between the current collector 23 and the electrode 2212 can be various, such as welding, bonding or abutting. For example, in the embodiment of this application, the current collector 23 and the electrode 2212 are welded together.

[0272] By providing a current collector 23 inside the casing 21 of the battery cell 20, the casing 21 and the tab 2212 of the electrode assembly 22 are connected through the current collector 23, thereby enabling the input or output of electrical energy of the battery cell 20. This structure is simple, easy to implement, and helps to reduce the assembly difficulty between the tab 2212 and the casing 21.

[0273] According to some embodiments of this application, refer to Figure 3 Please refer to further details. Figure 18 , Figure 18 This is a schematic diagram showing the connection between the current collector 23 and the tab 2212 of the electrode assembly 22 according to some embodiments of this application. The current collector 23 and the tab 2212 are welded together. Along the first direction X, the thickness of the tab 2212 is D5, and the thickness of the current collector 23 is D6, satisfying that D6≤1.5D5.

[0274] The current collector 23 is disposed at one end of the electrode assembly 22 in the first direction X, so that the current collector 23 can be welded to the tab 2212 located at one end of the electrode assembly 22 in the first direction X.

[0275] Along the first direction X, the thickness of the tab 2212 is D5. That is, after the multiple tab portions 22121 of the tab 2212 are bent relative to the first direction X by a process of smoothing or kneading and stacked on one end of the body 223 of the electrode assembly 22 in the first direction X, the size of the tab 2212 in the first direction X is D5.

[0276] Along the first direction X, the thickness of the current collector 23 is D6, that is, the dimension of the current collector 23 in the first direction X is D6.

[0277] D6 ≤ 1.5D5, meaning the thickness of the current collector 23 is less than or equal to 1.5 times the thickness of the tab 2212. For example, the thickness D6 of the current collector 23 can be 1.5 times, 1.4 times, 1.2 times, 1.25 times, 1 time, 0.9 times, 0.8 times, 0.75 times, or 0.5 times the thickness D5 of the tab 2212, etc.

[0278] During the experiment, experiments were conducted with different thicknesses for the current collector 23 and the tab 2212, to vary the ratio of their thicknesses. The aim was to measure the impact of this ratio on the welding and assembly process of the current collector 23 and the tab 2212 under different conditions. The experimental results are as follows:

[0279]

[0280] The experimental data above shows that when the ratio of the thickness of the current collector 23 to the thickness of the tab 2212 is greater than 1.5, the tab 2212 is prone to burn-through, resulting in poor assembly quality between the current collector 23 and the tab 2212, which fails to meet assembly requirements. When the ratio of the thickness of the current collector 23 to the thickness of the tab 2212 is less than or equal to 1.5, the burn-through phenomenon of the tab 2212 can be alleviated, which is beneficial to improving the assembly quality between the current collector 23 and the tab 2212. Therefore, the ratio of the thickness of the current collector 23 to the thickness of the tab 2212 is set to be less than or equal to 1.5, i.e., D6≤1.5D5.

[0281] By setting the thickness of the current collector 23 in the first direction X to be less than or equal to 1.5 times the thickness of the tab 2212 in the first direction X, the phenomenon that the welding power required to weld the current collector 23 and the tab 2212 is too large due to the thickness of the current collector 23 being too large compared to the thickness of the tab 2212 can be alleviated. This can effectively reduce the risk of the tab 2212 being welded through, thereby reducing the phenomenon of damage to the electrode assembly 22 and improving the production quality of the battery cell 20.

[0282] In some embodiments, see Figure 18As shown, the current collector 23 is welded to the tab 2212 to form a solder mark 24. Along the first direction X, the solder mark 24 covers at least one protrusion 22121a of the tab portion 22121.

[0283] Along the first direction X, the solder mark 24 covers the protrusion 22121a of at least one tab 22121, that is, in the first direction X, the position where the current collector 23 and the tab 2212 are welded to each other corresponds to the protrusion 22121a of at least one tab 22121.

[0284] By setting the weld mark 24 formed by welding the current collector 23 and the tab 2212 together as a protrusion 22121a covering at least one tab portion 22121 in the first direction X, the position where the current collector 23 and the tab 2212 are welded together is located in the area of ​​the tab 2212 thickened by the protrusion 22121a, which helps to further reduce the risk of the tab 2212 being burned through during assembly.

[0285] According to some embodiments of this application, this application also provides a battery 100, which includes a battery cell 20 of any of the above schemes.

[0286] The battery 100 may also include a housing 10, in which the battery cells 20 are housed.

[0287] Optionally, the battery cell 20 housed within the housing 10 can be one or more, for example, in Figure 2 In this embodiment, battery 100 comprises multiple battery cells 20, all of which are housed within housing 10. The multiple battery cells 20 can be connected in series, parallel, or a combination thereof; a combination thereof means that some of the multiple battery cells 20 are connected in series while others are connected in parallel. The multiple battery cells 20 can be directly connected in series, parallel, or a combination thereof, and then the entire assembly of the multiple battery cells 20 is housed within housing 10.

[0288] According to some embodiments of this application, this application also provides an electrical device, which includes a battery 100 of any of the above schemes, and the battery 100 is used to provide electrical energy to the electrical device.

[0289] The electrical device can be any of the aforementioned devices or systems that use battery 100.

[0290] According to some embodiments of this application, see Figures 4 to 10As shown, this application provides an electrode assembly 22, which has a wound structure. The electrode assembly 22 includes two electrode pieces 221 with opposite polarities and a separator 222 for isolating the two electrode pieces 221. The two electrode pieces 221 and the separator 222 are wound along the winding direction Y to form a main body 223 and two tabs 2212, and the tabs 2212 of the two electrode pieces 221 are respectively disposed at both ends of the main body 223 in the first direction X. The electrode piece 221 includes a main body portion 2211 and a tab 2212, and the extending direction of the main body portion 2211 is consistent with the winding direction Y. The main body 2211 includes a substrate 22111 and active material layers 22112 disposed on both sides of the substrate 22111. The substrate 22111 includes a coating area 22111a and a spacer area 22111b. The coating area 22111a and the spacer area 22111b are arranged along a first direction X. The active material layer 22112 is disposed in the coating area 22111a. The tab 2212 includes a plurality of tab portions 22121. The tab portions 22121 are connected to the end of the spacer area 22111b away from the coating area 22111a in the first direction X. The plurality of tab portions 22121 are spaced apart along the winding direction Y. At least a portion of the plurality of tab portions 22121 are stacked along the first direction X to form a tab 2212 at one end of the electrode assembly 22 along the first direction X. The thickness of the tab 2212 in the first direction X is D5, which satisfies 0.2mm≤D5≤2.5mm. Along the thickness direction Z of the tab, a plurality of protrusions 22121a are formed on one side of the tab 22121. A groove 22121b is formed on the side of the tab 22121 away from the protrusions 22121a and corresponding to the position of the protrusions 22121a. Along the first direction X, in two adjacent tabs 22121, the protrusions 22121a of one tab 22121 are misaligned with the grooves 22121b of the other tab 22121. Along the thickness direction Z of the awl, the projected area of ​​the awl 22121 is S1, and the sum of the projected areas of the multiple protrusions 22121a on the awl 22121 is S2, satisfying that S2 / S1≥0.5. The awl 22121 includes a main body region 22121c that does not overlap with the projection of the protrusions 22121a along the thickness direction Z of the awl. Along the thickness direction Z of the awl, the maximum size of the awl 22121 is D1, and the thickness of the main body region 22121c is D2, satisfying that 2≤D1 / D2≤8. Among them, the protrusion 22121a is a hemispherical structure, and the multiple protrusions 22121a include multiple rows of protrusions 22121a arranged at intervals. Each row of protrusions 22121a includes multiple protrusions 22121a arranged at intervals. The diameter of the protrusion 22121a in the direction perpendicular to the thickness direction Z of the electrode ear is W1, which satisfies 0.3mm≤W1≤2mm.

[0291] According to some embodiments of this application, see Figure 3 as well as Figure 18As shown, this application provides a battery cell 20, which includes a housing 21, an electrode assembly 22, and a current collector 23. The electrode assembly 22 is housed within the housing 21. Along a first direction X, the current collector 23 is disposed between the housing 21 and a tab 2212, connecting the housing 21 and the tab 2212. The current collector 23 is welded to the tab 2212 to form a solder mark 24. Along the first direction X, the solder mark 24 covers at least one protrusion 22121a of the tab 22121. The thickness of the tab 2212 is D5 along the first direction X, and the thickness of the current collector 23 is D6, satisfying that D6 ≤ 1.5D5.

[0292] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0293] 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. A battery cell, characterized in that, It includes a housing, an electrode assembly, and a current collector, wherein the electrode assembly is housed within the housing; The electrode assembly includes two electrodes with opposite polarities and a separator for isolating the two electrodes. The two electrodes and the separator are wound along the winding direction to form a main body and two tabs. The electrode tab and the main body are arranged along a first direction. The electrode tab includes a plurality of electrode tab portions spaced apart along the winding direction. The electrode tab portions are bent relative to the first direction. At least a portion of the plurality of electrode tab portions are stacked along the first direction. The electrode tab portion has a protrusion formed on at least one side in its thickness direction, and the electrode tab portion has a groove formed on the side opposite to the protrusion and corresponding to the position of the protrusion. Along the first direction, in two adjacent electrode portions, the protrusion of one electrode portion is misaligned with the groove of the other electrode portion; The current collector is disposed between the outer shell and the electrode tab in the first direction. The current collector is welded to the electrode tab to form a weld mark. Along the first direction, the weld mark covers at least one of the protrusions of the electrode tab.

2. The battery cell according to claim 1, characterized in that, Along the thickness direction of the electrode portion, at least one side of the electrode portion has a plurality of protrusions.

3. The battery cell according to claim 2, characterized in that, In the unfolded state of the electrode sheet, along the thickness direction of the electrode tab, the projected area of ​​the electrode tab is S1, and the sum of the projected areas of the plurality of protrusions on the electrode tab is S2, satisfying that S2 / S1≥0.

5.

4. The battery cell according to claim 1, characterized in that, The electrode ear includes a main body region that does not overlap with the projection of the protrusion in the thickness direction of the electrode ear, and the protrusion protrudes from the main body region along the thickness direction of the electrode ear; Along the thickness direction of the electrode tab, the maximum dimension of the electrode tab is D1, and the thickness of the main body region is D2, satisfying that 2≤D1 / D2≤8.

5. The battery cell according to claim 1, characterized in that, The tab portion has multiple rows of protrusions, and each row of protrusions includes multiple protrusions spaced apart.

6. The battery cell according to claim 5, characterized in that, The maximum dimension of the protrusion in the direction perpendicular to the thickness direction of the tab is W1, which satisfies 0.3mm≤W1≤2mm.

7. The battery cell according to claim 1, characterized in that, The tab portion has a plurality of protrusions arranged at intervals, and the two ends of the protrusions extend to the two ends of the tab portion in a direction perpendicular to the arrangement direction of the plurality of protrusions.

8. The battery cell according to claim 7, characterized in that, Along the arrangement direction of the plurality of protrusions, the width of the protrusion is W2, which satisfies 0.3mm≤W2≤2mm.

9. The battery cell according to any one of claims 1-8, characterized in that, Along the thickness direction of the tab portion, the tab portion includes a plurality of foils stacked together. A protrusion is formed on one side of the foil, and a recess is formed on the other side at a position corresponding to the protrusion. In two adjacent foils, the protrusion of one foil is accommodated in the recess of the other foil. The protrusion located on one side of the electrode ear along the thickness direction is the protrusion.

10. The battery cell according to claim 9, characterized in that, Multiple foils are welded together to form the protrusions and recesses on the foils.

11. The battery cell according to claim 9, characterized in that, The electrode includes a main body portion, a plurality of electrode tabs connected to the main body portion, and the main body portions of two electrode portions and the separator are wound along the winding direction to form the main body portion. The main body portion includes a substrate and an active material layer disposed on at least one side of the substrate. The plurality of foils include a first foil and a second foil stacked together, the first foil being connected to one end of the substrate in the first direction and integrally formed with the substrate, and the second foil being separately disposed from the substrate.

12. The battery cell according to claim 11, characterized in that, The substrate includes a coating area and a spacer area, the coating area and the spacer area are arranged along the first direction, the active material layer is disposed in the coating area, and the spacer area connects the coating area and the first foil.

13. The battery cell according to claim 11, characterized in that, Along the thickness direction of the tab portion, the thickness of the first foil is D3 and the thickness of the second foil is D4, satisfying 0.5≤D3 / D4≤2.

14. The battery cell according to claim 11, characterized in that, Along a direction perpendicular to the thickness direction of the tab, the end of the second foil near the substrate does not extend beyond the end of the first foil connected to the substrate.

15. The battery cell according to claim 11, characterized in that, Along the direction perpendicular to the thickness direction of the tab, the distance between the end of the first foil away from the substrate and the end of the second foil away from the substrate is L, which satisfies L≤2mm.

16. The battery cell according to claim 11, characterized in that, The first foil and the second foil are made of the same material.

17. The battery cell according to claim 1, characterized in that, The electrode includes a main body portion, and a plurality of electrode tabs are connected to one end of the main body portion in the first direction. The main body portions of two electrode portions and the separator are wound together along the winding direction to form the main body. The main body includes a substrate and an active material layer disposed on at least one side of the substrate. The substrate includes a coating area and a spacer area. The coating area and the spacer area are arranged along the first direction. The active material layer is disposed in the coating area. The spacer area connects the coating area and the tab.

18. The battery cell according to claim 17, characterized in that, The tab portion is integrally formed with the spacer region.

19. The battery cell according to claim 1, characterized in that, Along the first direction, the thickness of the electrode tab is D5, which satisfies 0.2mm≤D5≤2.5mm.

20. The battery cell according to claim 1, characterized in that, Along the first direction, the two electrodes are respectively disposed at both ends of the main body.

21. The battery cell according to claim 1, characterized in that, The main body is cylindrical.

22. The battery cell according to claim 1, characterized in that, Along the first direction, the thickness of the electrode tab is D5, and the thickness of the current collector is D6, satisfying that D6≤1.5D5.

23. A battery, characterized in that, Includes the battery cell as described in any one of claims 1-22.

24. An electrical appliance, characterized in that, Includes the battery as described in claim 23.

Images