Electrode assembly, battery cell, battery and electric device

Abstract

The invention provides an electrode assembly, a battery monomer, a battery and a power utilization device, and belongs to the technical field of batteries. Wherein the electrode assembly comprises two pole pieces with opposite polarities and a separator for separating the two pole pieces, and the two pole pieces and the separator are wound along the winding direction to form a main body and two tabs. The tab and the main body are arranged along a first direction, the tab comprises a plurality of tab parts which are arranged at intervals along a winding direction, the tab parts are bent relative to the first direction, at least one part of the plurality of tab parts are stacked along the first direction, and bulges are formed on at least one side of the tab parts in the thickness direction. By arranging the bulges on the tab parts, the thicknesses of the plurality of tab parts which are stacked together can be increased after the tab parts are bent, and the phenomenon that the local thickness of the tab is relatively small can be relieved, so that the risk that the tab is welded through in the subsequent assembly process is reduced, the phenomenon that the electrode assembly is damaged is reduced, and the reliability of the electrode assembly is improved. Therefore, the production quality of the battery monomer with the electrode assembly is improved.

Description

Electrode assembly, battery cell, battery and electrical device Technical Field

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

[0002] In recent years, new energy vehicles have experienced rapid development. Within the electric vehicle sector, power batteries, as the power source for electric vehicles, play an irreplaceable and important role. With the vigorous promotion of new energy vehicles, demand for power battery products is also growing. Batteries consist of battery cells, each housing houses an electrode assembly. Connecting the electrode assembly to the housing enables the input and output of electrical energy from the battery cell. However, existing battery cells often suffer from electrode assembly damage during production and assembly, resulting in poor battery cell production quality and hindering the improvement of battery cell product qualification rates.

[0003] Summary of the Invention

[0004] The embodiments of the present application provide an electrode assembly, a battery cell, a battery, and an electrical device, which can effectively improve the production quality of the battery cell.

[0005] In a first aspect, an embodiment of the present application provides an electrode assembly, comprising two pole pieces with opposite polarities and an isolating member for isolating the two pole pieces, wherein the two pole pieces and the isolating member are wound along a winding direction to form a main body and two pole ears; wherein the pole ears and the main body are arranged along the first direction, the pole ears comprise a plurality of pole ear portions spaced apart along the winding direction, the pole ear portions are bent relative to the first direction, at least a portion of the plurality of pole ear portions are stacked along the first direction, and a protrusion is formed on at least one side of the pole ear portion in its thickness direction.

[0006] In the above technical solution, two pole pieces of opposite polarity and a separator are wound along a winding direction to form an electrode assembly having a wound structure, 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 tab is provided with a plurality of 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 plurality of tab portions of the tab can be stacked along the first direction. A protrusion is provided on at least one side of the tab portion to increase the thickness of the stacked plurality of tab portions, and to alleviate the phenomenon of locally thinner tab portions after stacking. This improves the production quality of the tab, reduces the risk of the tab being welded through during subsequent assembly, and thus helps reduce 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 having such an electrode assembly.

[0007] In some embodiments, a plurality of protrusions are formed on at least one side of the pole lug portion along a thickness direction of the pole lug portion.

[0008] In the above technical solution, by arranging multiple protrusions on at least one side of the pole ear portion, the pole ear portion is bent relative to the first direction and multiple pole ear portions are stacked along the first direction, so that the area with a cavity between two stacked and adjacent pole ear portions can be effectively increased, which is beneficial to further increase the overall thickness of the pole ear in the first direction, and can improve the uniformity of the pole ear thickness, thereby further alleviating the phenomenon of the pole ear being welded through during subsequent assembly processing.

[0009] In some embodiments, along the thickness direction of the pole ear portion, the projected area of ​​the pole ear portion is S1, and the sum of the projected areas of the plurality of protrusions on the pole ear portion is S2, satisfying S2 / S1≥0.5.

[0010] In the above technical solution, by setting the sum of the projected areas of the multiple protrusions on the pole ear portion in the thickness direction of the pole ear portion to be greater than or equal to half of the projected area of ​​the pole ear portion in the thickness direction of the pole ear portion, that is, the area occupied by the multiple protrusions on the pole ear portion is half or more of the pole ear portion, so that there is a sufficient area on the pole ear portion to be provided with protrusions, so that after the multiple pole ear portions of the pole ear are stacked along the first direction, the pole ear has a sufficient thickness, and the uniformity of the thickness of the pole ear can be effectively improved, so as to reduce the risk of the pole ear being welded through during the subsequent assembly process.

[0011] In some embodiments, the pole ear portion includes a main body area that does not overlap with the projection of the protrusion in the thickness direction of the pole ear portion, and the protrusion protrudes from the main body area along the thickness direction of the pole ear portion; along the thickness direction of the pole ear portion, the maximum dimension of the pole ear portion is D1, and the thickness of the main body area is D2, satisfying 2≤D1 / D2≤8.

[0012] In the above technical solution, the pole ear portion has a main area that does not overlap with the projection of the protrusion in the thickness direction of the pole ear portion, and the protrusion protrudes from the main area in the thickness direction of the pole ear portion, that is, the main area of ​​the pole ear portion is an area of ​​the pole ear portion where no protrusion is provided. By setting the maximum dimension of the pole ear portion in the thickness direction of the pole ear portion to 2 to 8 times the thickness of the main area, that is, the maximum thickness of the pole ear portion after the protrusion is provided is 2 to 8 times the thickness of the main area of ​​the pole ear portion, so that after the pole ear portion is bent relative to the first direction, the thickness of the multiple pole ear portions of the pole ear stacked on each other along the first direction can be effectively increased, so as to achieve an increase in the thickness of the pole ear, and thus can effectively alleviate the phenomenon of the pole ear being welded through during the subsequent assembly process.

[0013] In some embodiments, the tab portion is formed with multiple rows of protrusions, and each row of protrusions includes a plurality of protrusions arranged at intervals.

[0014] In the above technical solution, multiple rows of protrusions are arranged on the pole ear portion, and each row of protrusions includes multiple protrusions arranged at intervals, so that the multiple protrusions on the pole ear portion are arranged in an array, so that after the multiple pole ear portions of the pole ear are stacked along the first direction, the area with a cavity between the two stacked and adjacent pole ear portions can be effectively increased, which is beneficial to further increase the overall thickness of the pole ear in the first direction, and can effectively improve the uniformity of the pole ear thickness, so as to reduce the phenomenon of the pole ear being welded through during the subsequent assembly process.

[0015] In some embodiments, the maximum dimension of the protrusion in a direction perpendicular to the thickness direction of the tab portion is W1, satisfying 0.3 mm ≤ W1 ≤ 2 mm.

[0016] In the above technical solution, by setting the maximum dimension of the protrusion in the direction perpendicular to the thickness direction of the pole ear portion to 0.3mm to 3mm, that is, the maximum dimension 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 great due to the protrusion being too small, so as to reduce the processing difficulty of the pole ear portion; on the other hand, it can alleviate the phenomenon that the number of multiple protrusions on the pole ear portion is limited due to the protrusion being too large.

[0017] In some embodiments, the tab portion is formed with a plurality of protrusions arranged at intervals, and two ends of the protrusions extend to two ends of the tab portion respectively along a direction perpendicular to an arrangement direction of the plurality of protrusions.

[0018] In the above technical solution, a plurality of protrusions are formed on the pole ear portion at intervals, and both ends of the protrusions extend to both ends of the pole ear portion, that is, the protrusions are strip structures arranged on the pole ear portion, so as to realize a structure in which a plurality of protrusions are arranged on the pole ear portion. The use of such a structure is conducive to reducing the difficulty of arranging the protrusions on the pole ear portion, thereby improving the processing efficiency of the pole ear portion.

[0019] In some embodiments, along the arrangement direction of the plurality of protrusions, the width of the protrusion is W2, satisfying 0.3 mm ≤ W2 ≤ 2 mm.

[0020] In the above technical solution, by setting the width of the protrusion in the arrangement direction of the 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 great due to the protrusion width being too small, so as to reduce the processing difficulty of the pole ear part; on the other hand, it can alleviate the phenomenon that the number of multiple protrusions on the pole ear part is limited due to the protrusion width being too large.

[0021] In some embodiments, along the thickness direction of the pole ear portion, the pole ear portion includes a plurality of foil materials stacked together, a convex portion is formed on one side of the foil material, and a concave portion is formed on the other side at a position corresponding to the convex portion, and in two adjacent foil materials, the convex portion of one foil material is accommodated in the concave portion of the other foil material; wherein, along the thickness direction of the pole ear portion, the convex portion located on one side of the pole ear portion is the protrusion.

[0022] In the above technical solution, the pole ear portion is set as a structure in which multiple foils are stacked, and a convex portion is formed on one side of the foil and a concave portion is formed on the other side, so that after the multiple foils are stacked, the convex portions and concave portions of the two adjacent foils can be embedded in each other, so as to realize that a convex portion is formed on one side of the pole ear portion in the thickness direction of the pole ear portion. The pole ear portion with such a structure can effectively increase the thickness and structural strength of the pole ear portion itself, so that after the multiple pole ear portions of the pole ear are stacked along the first direction, the overall thickness and structural strength of the pole ear can be further increased, so as to further reduce the risk of the pole ear being welded through during the subsequent assembly process.

[0023] In some embodiments, a plurality of the foils are connected by welding to form the protrusions and the recesses on the foils.

[0024] In the above technical solution, welding is used to connect multiple stacked foils, and convex and concave portions are formed at the positions where the multiple foils are welded to each other. On the one hand, this is beneficial to improving the connection strength and connection stability between the multiple foils, and on the other hand, it is beneficial to reducing the processing difficulty of forming concave and convex portions on the foils, so as to optimize the production rhythm of the pole pieces, thereby effectively improving the production efficiency of the pole pieces.

[0025] In some embodiments, the pole piece includes a main body, a plurality of the pole ear portions are connected to the main body, the main bodies of the two pole pieces and the isolation members are wound along the winding direction to form the main body, the main body includes a substrate and an active material layer arranged on at least one side of the substrate; the plurality of foils include a first foil and a second foil arranged in a stacked manner, the first foil is connected to one end of the substrate in the first direction and is integrally formed with the substrate, and the second foil is separately arranged from the substrate.

[0026] In the above technical solution, the multiple foils include a first foil that is integrally formed with the substrate of the main body of the electrode. In actual production, an area without an active material layer can be reserved on the substrate, so that the first foil can be set on the area, and 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, so as to achieve an increase in the thickness and structural strength of the electrode ear. The electrode using this structure can effectively reduce the process difficulty of connecting the electrode ear to the substrate, which is conducive to improving the production efficiency of the electrode assembly.

[0027] In some embodiments, 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.

[0028] In the above technical solution, a coating area coated with an active material layer and a spacer area not coated with an active material layer are provided on the substrate, so that the first foil of the pole ear portion can be connected to the coating area through the spacer area, so that the pole ear portion and the active material layer are spaced apart in the first direction. On the one hand, the electrode assembly adopting this structure can isolate the stress generated by the pole ear portion during the bending process relative to the first direction through the spacer area, so as to reduce the risk of fracture of the active material layer provided on the coating area. On the other hand, during the subsequent welding of the pole ear with other components, the impact on the active material layer during the welding process can be reduced, thereby alleviating the phenomenon of damage to the active material layer, which is beneficial to improving the production quality of the electrode assembly.

[0029] In some embodiments, along the thickness direction of the electrode ear portion, the thickness of the first foil is D3, and the thickness of the second foil is D4, satisfying 0.5≤D3 / D4≤2.

[0030] In the above technical solution, by setting the thickness of the first foil to be 0.5 to 2 times the thickness of the second foil, that is, the thickness of the first foil is 0.5 to 2 times the thickness of the second foil, the problem of difficulty in assembling the first and second foils due to the large difference in thickness between the first and second foils can be alleviated, thereby reducing the difficulty in processing the tab portion of this structure. In addition, on the one hand, it can alleviate the problem of damage to the second foil during the mutual welding process caused by the thickness of the first foil being too great compared to the thickness of the second foil, and on the other hand, it can alleviate the problem of damage to the first foil during the mutual welding process caused by the thickness of the second foil being too great compared to the thickness of the first foil.

[0031] In some embodiments, along a direction perpendicular to the thickness direction of the tab portion, an end of the second foil material close to the substrate does not extend beyond an end of the first foil material connected to the substrate.

[0032] In the above technical solution, by setting the second foil material in a direction perpendicular to the thickness direction of the electrode ear portion so as not to exceed the end of the first foil material connected to the substrate, the interference effect between the second foil material and the active material layer arranged on one side of the substrate can be effectively alleviated, thereby reducing the risk of the active material layer being damaged by the second foil material.

[0033] In some embodiments, along the direction perpendicular to the thickness direction of the tab portion, a distance L between an end of the first foil away from the substrate and an end of the second foil away from the substrate satisfies L≤2 mm.

[0034] In the above technical solution, by setting the spacing between the end of the first foil away from the substrate and the end of the second foil away from the substrate in a direction perpendicular to the thickness direction of the pole ear portion to be less than or equal to 2 mm, that is, the dimension of the end of the first foil away from the substrate exceeding the end of the second foil away from the substrate is less than or equal to 2 mm, or the dimension of the end of the second foil away from the substrate exceeding the end of the first foil away from the substrate is less than or equal to 2 mm, thereby alleviating the problem that the first foil exceeds the second foil too much or the second foil exceeds the first foil too much due to the length of the first foil or the length of the second foil being too large, thereby causing the pole ear portion to be redundant or inverted into the electrode assembly, thereby facilitating improving the production quality and use reliability of the electrode assembly.

[0035] In some embodiments, the first foil and the second foil are made of the same material.

[0036] In the above technical solution, by setting the first foil and the second foil to be the same material, on the one hand, the polarity of the tab portion can be stabilized, and on the other hand, the process difficulty of connecting the first foil and the second foil can be reduced.

[0037] In some embodiments, the pole piece includes a main body, a plurality of pole ear portions are connected to one end of the main body in the first direction, and the main bodies and the isolation members of the two pole pieces are wound along the winding direction to form the main body; wherein, the main body includes a substrate and an active material layer arranged 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 arranged in the coating area, and the spacer area connects the coating area and the pole ear portion.

[0038] In the above technical solution, a coating area coated with an active material layer and a spacer area not coated with an active material layer are provided on the substrate, so that the pole ear portion can be connected to the coating area through the spacer area, so that the pole ear portion and the active material layer are spaced apart in the first direction. On the one hand, the electrode assembly adopting this structure can isolate the stress generated by the pole ear portion during the bending process relative to the first direction through the spacer area, so as to reduce the risk of fracture of the active material layer provided on the coating area. On the other hand, during the subsequent welding of the pole ear with other components, the impact on the active material layer during the welding process can be reduced, thereby alleviating the phenomenon of damage to the active material layer, which is beneficial to improving the production quality of the electrode assembly.

[0039] In some embodiments, the tab portion and the spacer region are integrally formed.

[0040] In the above technical solution, by setting the pole ear portion as a structure integrally formed with the spacer area of ​​the substrate, the pole ear portion can be a part of the substrate during the actual production process. After reserving an area on the substrate where the active material layer is not set, the pole ear portion can be set on the area to reduce the process difficulty of connecting the pole ear portion to the substrate, which is beneficial to improving the production efficiency of the electrode assembly.

[0041] In some embodiments, along the thickness direction of the pole ear portion, a groove is formed on a side of the pole ear portion away from the protrusion and corresponding to a position of the protrusion.

[0042] In the above technical solution, a groove is provided on the side of the pole ear away from the protrusion and at the position corresponding to the protrusion, so that the pole ear of this structure can be formed with a protrusion on the pole ear through processes such as stamping or rolling. On the one hand, it is beneficial to reduce the processing difficulty of the pole ear and improve the processing efficiency of the pole ear. On the other hand, there is no need to provide a protrusion on one side of the pole ear by adding material, which is beneficial to reducing the production cost of the pole ear and reducing the weight of the pole ear.

[0043] In some embodiments, along the first direction, in two adjacent pole lug portions, the protrusion of one pole lug portion and the groove of the other pole lug portion are staggered.

[0044] In the above technical solution, by setting the protrusion of one pole ear part and the groove of the other pole ear part in two adjacent pole ear parts in the first direction as a mutually staggered structure, the phenomenon of mutual offset after the protrusion and the groove overlap can be effectively alleviated, so that the pole ear has sufficient thickness in the first direction, which is beneficial to reduce the risk of the pole ear of the electrode assembly being welded through during the subsequent assembly process.

[0045] In some embodiments, along the first direction, the thickness of the tab is D5, satisfying 0.2 mm ≤ D5 ≤ 2.5 mm.

[0046] In the above technical solution, by setting the thickness of the tab in the first direction to 0.2 mm to 2.5 mm, on the one hand, the risk of the tab being welded through due to the tab being too thin can be alleviated, thereby reducing the risk of the electrode assembly being damaged during the subsequent assembly process. On the other hand, the phenomenon of the tab occupying too much space due to the tab being too thick can be alleviated, which is conducive to optimizing the internal space of the battery cell with such an electrode assembly to improve the energy density of the battery cell.

[0047] In some embodiments, along the first direction, the two tabs are respectively disposed at two ends of the main body.

[0048] In the above technical solution, by respectively arranging the two pole ears of the electrode assembly at the two ends of the main body in the first direction, that is, the two pole ears are respectively formed at the two ends of the electrode assembly in the first direction, it is convenient to subsequently assemble the electrode assembly, which is beneficial to reduce the difficulty of assembling the battery cell with such an electrode assembly, and can reduce the interference or mutual contact between the two pole ears, thereby helping to reduce the risk of short circuit of the electrode assembly.

[0049] In some embodiments, the body is cylindrical.

[0050] In the above technical solution, the main body of the electrode assembly is set to a cylindrical structure, so as to facilitate subsequent processing to form a battery cell with a cylindrical structure.

[0051] In a second aspect, an embodiment of the present application further provides a battery cell comprising a housing and the above-mentioned electrode assembly; the electrode assembly is accommodated in the housing.

[0052] In some embodiments, the battery cell further includes a current collecting member; the current collecting member is disposed between the housing and the tab along the first direction, and the current collecting member connects the housing and the tab.

[0053] In the above technical solution, a current collecting component is provided in the shell of the battery cell to connect the shell and the tabs of the electrode assembly through the current collecting component, 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 difficulty of assembling the tabs and the shell.

[0054] In some embodiments, the current collecting member is welded to the tab. Along the first direction, the thickness of the tab is D5, and the thickness of the current collecting member is D6, satisfying D6≤1.5D5.

[0055] In the above technical solution, by setting the thickness of the current collecting component 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 of excessive welding power required for welding the current collecting component and the tab due to the thickness of the current collecting component being too large than the thickness of the tab can be alleviated, thereby effectively reducing the risk of the tab being welded through, reducing the phenomenon of damage to the electrode assembly, and helping to improve the production quality of battery cells.

[0056] In some embodiments, the current collecting member is connected to the electrode tab by welding to form a weld mark, and along the first direction, the weld mark covers the protrusion of at least one of the electrode tabs.

[0057] In the above technical solution, the weld mark formed by welding the current collecting member and the pole tab to each other is set to cover the protrusion of at least one pole tab portion in the first direction, that is, in the first direction, the position where the current collecting member and the pole tab are welded to each other is set corresponding to the protrusion of at least one pole tab portion, so that the position where the current collecting member and the pole tab are welded to each other is located in the area where the pole tab is thickened by the protrusion, which is conducive to further reducing the risk of the pole tab being welded through during the assembly process.

[0058] In a third aspect, an embodiment of the present application further provides a battery comprising the above-mentioned battery cell.

[0059] In a fourth aspect, an embodiment of the present application further provides an electrical device comprising the above-mentioned battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0061] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0062] FIG2 is an exploded view of the structure of a battery provided in some embodiments of the present application;

[0063] FIG3 is an exploded view of the structure of a battery cell provided in some embodiments of the present application;

[0064] FIG4 is a cross-sectional view of an electrode assembly provided in some embodiments of the present application;

[0065] FIG5 is a cross-sectional view of an electrode assembly provided in some embodiments of the present application;

[0066] FIG6 is a schematic structural diagram of an electrode assembly during a winding process according to some embodiments of the present application;

[0067] FIG7 is a schematic diagram of the structure of the electrode sheet of the electrode assembly provided in some embodiments of the present application after unfolding;

[0068] FIG8 is a partial cross-sectional view of a pole piece after unfolding provided by some embodiments of the present application;

[0069] FIG9 is a schematic structural diagram of a tab portion provided in some embodiments of the present application;

[0070] FIG10 is a front view of a tab portion provided in some embodiments of the present application;

[0071] FIG11 is a schematic structural diagram of a tab portion provided in yet other embodiments of the present application;

[0072] FIG12 is a front view of a tab portion provided in some other embodiments of the present application;

[0073] FIG13 is a schematic structural diagram of a tab portion provided in some further embodiments of the present application;

[0074] FIG14 is a front view of a tab portion provided in some other embodiments of the present application;

[0075] FIG15 is a partial cross-sectional view of an unfolded pole piece provided in some other embodiments of the present application;

[0076] FIG16 is a cross-sectional view of a pole ear portion of a pole piece provided in some other embodiments of the present application;

[0077] FIG17 is a cross-sectional view of multiple tab portions of an electrode assembly provided by some embodiments of the present application after being stacked;

[0078] FIG18 is a schematic diagram showing the connection between the current collecting member and the electrode tab of the electrode assembly provided in some embodiments of the present application.

[0079] Icon: 1000-vehicle; 100-battery; 10-box; 11-first box body; 12-second box body; 20-battery cell; 21-housing; 211-shell; 2111-opening; 212-end cap; 22-electrode assembly; 221-pole piece; 2211-main body; 22111-substrate; 22111a-coating area; 22111b-spacer area; 22112-active material layer; 2212-ear; 22121 -ear portion; 22121a-protrusion; 22121b-groove; 22121c-main body; 22121d-foil; 22121e-convex portion; 22121f-concave portion; 22121g-first foil; 22121h-second foil; 222-isolator; 223-main body; 23-current collecting component; 24-weld stamp; 200-controller; 300-motor; X-first direction; Y-winding direction; Z-thickness direction of the ear portion. DETAILED DESCRIPTION

[0080] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0081] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0082] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0083] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0084] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0085] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0086] The term "plurality" used in this application refers to two or more (including two).

[0087] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0088] The battery cells can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc., which are not limited in the embodiments of the present application.

[0089] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of a battery cell, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0090] 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.

[0091] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0092] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may 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.).

[0093] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional 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-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0094] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0095] As an example, the negative electrode current collector can be a metal foil, a metal foam, or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium can be used. The metal foam can be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector 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.).

[0096] 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.

[0097] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is provided on either or both of the two facing surfaces of the negative electrode current collector.

[0098] 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.

[0099] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0100] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0101] In some embodiments, the separator is a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical and mechanical stability can be selected.

[0102] As an example, the main material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics.

[0103] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0104] 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 specifically limit the type of electrolyte, and the electrolyte can be selected based on needs. The electrolyte can be liquid, gel, or solid.

[0105] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into the wound structure.

[0106] In some embodiments, the electrode assembly is a laminate structure.

[0107] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0108] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0109] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0110] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, and a polygonal battery. The polygonal battery is, for example, a hexagonal battery, etc. There is no special limitation in this application.

[0111] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0112] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0113] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0114] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0115] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0116] Batteries, with their outstanding advantages of high energy density, low environmental pollution, high power density, long service life, wide adaptability, and low self-discharge coefficient, are a vital component in today's new energy development. A current collecting member is typically installed within the outer casing of a battery cell. During the assembly of the battery cell, the tabs of the electrode assembly are welded to the current collecting member, which is then connected to the outer casing to enable the input or output of electrical energy to the battery cell. This facilitates the assembly of the battery cell and reduces the difficulty of assembly.

[0117] For typical battery cells, the electrode assembly is typically welded to the current collecting member via the tabs to achieve electrical connection between the electrode assembly and the current collecting member. The tabs are typically formed by stacking multiple tab sheets. To reduce the difficulty of assembling the electrode assembly and the current collecting member, particularly for cylindrical electrode assemblies, a flattening or smoothing process is typically used during the production and assembly of the battery cell to flatten or smooth the multiple tab sheets. This improves the flatness of the tabs, allowing the tabs to be formed at one end of the electrode assembly, thereby reducing the difficulty of welding the tabs to the current collecting member. However, the tabs of existing electrode assemblies are prone to localized underthickness during the flattening or smoothing process, and are also prone to having an overall underthickness of the tabs after the multiple tab sheets are tightly fitted. This makes it easy for the tabs to be welded through during the welding process between the tabs and the current collecting member, resulting in a risk of damage to the electrode assembly. This results in poor production quality of the battery cell and is not conducive to improving the product qualification rate of the battery cell.

[0118] Based on the above considerations, in order to solve the problem of poor production quality of battery cells, an embodiment of the present application provides an electrode assembly, including two pole pieces with opposite polarities and an isolating member for isolating the two pole pieces, the two pole pieces and the isolating member are wound along a winding direction to form a main body and two pole ears; wherein, the pole ears and the main body are arranged along a first direction, the pole ears include a plurality of pole ear portions arranged at intervals along the winding direction, the pole ear portions are bent relative to the first direction, at least part of the plurality of pole ear portions are stacked along the first direction, and a protrusion is formed on at least one side of the pole ear portions in the thickness direction thereof.

[0119] In a pole piece of this structure, two pole pieces of opposite polarity 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 tab is provided with a plurality of 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 plurality of tab portions of the tab can be stacked along the first direction. A protrusion is provided on at least one side of the tab portion to increase the thickness of the stacked plurality of tab portions, and to alleviate the phenomenon of locally thinner tab portions after stacking. This improves the production quality of the tab, reduces the risk of the tab being welded through during subsequent assembly, and further helps reduce 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 having this electrode assembly.

[0120] The electrode sheets disclosed in the embodiments of this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power supply system comprising the electrode assembly, battery cells, or batteries disclosed in this application can be used to construct such electrical devices. This effectively mitigates the problem of electrode assembly tabs being welded through during the production and assembly of battery cells, thereby improving the production quality of battery cells.

[0121] The present invention provides an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0122] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0123] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000. The battery 100 can be arranged at the bottom of the vehicle 1000, or at the head of the vehicle 1000, or at the tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can be used as an operating power source or a power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0124] In some embodiments of the present application, the battery 100 can not only serve as the operating power source or usage power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0125] Please refer to Figure 2, which is an exploded view of the structure of a battery 100 provided in some embodiments of the present application. The battery 100 may include a housing 10 and a battery cell 20, wherein the battery cell 20 is configured to be accommodated in the housing 10.

[0126] The housing 10 is used to provide assembly space for the battery cells 20 and can have various structures. In some embodiments, the housing 10 can include a first housing body 11 and a second housing body 12. The first housing body 11 and the second housing body 12 overlap each other, and the first housing body 11 and the second housing body 12 together define an assembly space for accommodating the battery cells 20. The second housing body 12 can be a hollow structure with one end open. The first housing body 11 can be a plate-like structure, and the first housing body 11 overlaps the open side of the second housing body 12, so that the first housing body 11 and the second housing body 12 jointly define the assembly space. The first housing body 11 and the second housing body 12 can also be hollow structures with one end open, with the open side of the first housing body 11 overlapping 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 have various shapes, such as a cylinder, a rectangular parallelepiped, etc. For example, in Figure 2, the housing 10 is in the shape of a rectangular parallelepiped.

[0127] In the battery 100, the number of battery cells 20 disposed in the housing 10 may be one or more. When there are multiple battery cells 20 disposed in the housing 10, the multiple battery cells 20 may be connected in series, in parallel, or in a mixed connection. Mixed connection means that the multiple battery cells 20 are connected in series and in parallel. The multiple battery cells 20 may be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the multiple battery cells 20 may be accommodated in the housing 10. Of course, the battery 100 may also be a battery module formed by first connecting multiple battery cells 20 in series, in parallel, or in a mixed connection, and then the multiple battery modules may be connected in series, in parallel, or in a mixed connection to form a whole, and then accommodated in the housing 10. The battery 100 may also include other structures. For example, the battery 100 may also include a busbar component, which is used to connect the multiple battery cells 20 to achieve electrical connection between the multiple battery cells 20.

[0128] 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 cells 20 are not limited thereto. The battery cells 20 can be cylindrical, flat, rectangular, or other shapes. For example, in FIG2 , the battery cells 20 are cylindrical.

[0129] 2 and further refer to FIG3 , which is an exploded view of a battery cell 20 according to some embodiments of the present invention. The battery cell 20 may include a housing 21 and an electrode assembly 22 , wherein the electrode assembly 22 is accommodated in the housing 21 .

[0130] The housing 21 can also be used to contain an electrolyte, such as an electrolyte solution. The housing 21 can have various structural forms, such as a cylinder, a rectangular parallelepiped, or a prismatic structure. Similarly, the housing 21 can be made of various materials, such as copper, iron, aluminum, steel, or an aluminum alloy.

[0131] In some embodiments, the housing 21 may include a shell 211 and an end cover 212. A accommodating cavity is formed inside the shell 211, and the accommodating cavity has an opening 2111. The accommodating cavity is used to accommodate the electrode assembly 22, that is, the shell 211 is a hollow structure with an opening 2111 on one side. The end cover 212 covers the opening 2111 of the shell 211 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 22 and the electrolyte.

[0132] When assembling the battery cell 20 , the electrode assembly 22 may be placed in the housing 211 first, and the housing 211 may be filled with electrolyte. The end cap 212 may then be placed on the opening 2111 of the housing 211 to complete the assembly of the battery cell 20 .

[0133] The shell 211 can be of various shapes, such as a cylinder, a cuboid, etc. The shape of the shell 211 can be determined according to the specific shape of the electrode assembly 22. For example, if the electrode assembly 22 is a cylindrical structure, a shell 211 with a cylindrical structure can be selected; if the electrode assembly 22 is a cuboid structure, a shell 211 with a cuboid structure can be selected. Of course, the end cover 212 can also be of various structures, such as the end cover 212 being a plate-like structure, a hollow structure with an opening 2111 at one end, etc. For example, in Figure 3, the electrode assembly 22 is a cylindrical structure, and correspondingly, the shell 211 is a cylindrical structure, the end cover 212 is a cylindrical plate-like structure, and the end cover 212 covers the opening 2111 of the shell 211.

[0134] Of course, it is understandable that the shell 21 is not limited to the above structure. The shell 21 can also be other structures. For example, the shell 21 includes a shell body 211 and two end covers 212. The shell body 211 is a hollow structure with openings 2111 on opposite sides. One end cover 212 corresponds to an opening 2111 of the shell body 211 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 22 and the electrolyte.

[0135] 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 the end cap 212. Alternatively, the positive electrode terminal may be mounted on the end of the housing 211 opposite the end cap 212, and the negative electrode terminal may be mounted on the end cap 212. Alternatively, both the positive electrode terminal and the negative electrode terminal may be mounted on the end cap 212, or both may be mounted on the end cap 212 or on the end of the housing 211 opposite the end cap 212. The positive electrode terminal and the negative electrode terminal are both used to electrically connect to the electrode assembly 22 to enable the input or output of electrical energy from the battery cell 20. The positive electrode terminal and the negative electrode terminal may be directly connected to the electrode assembly 22, such as by welding or abutting, or indirectly connected to the electrode assembly 22, such as by first connecting the positive electrode terminal and the negative electrode terminal to other components and then abutting or welding the positive electrode terminal and the negative electrode terminal to the electrode assembly 22 through other components.

[0136] 3 , the battery cell 20 may further include a current collecting member 23 , which is housed in the housing 21 . The current collecting member 23 is used to connect the electrode assembly 22 and the positive electrode terminal or the negative electrode terminal of the housing 21 to enable input or output of electrical energy of the battery cell 20 .

[0137] The current collecting member 23 serves to connect the electrode assembly 22 and the positive electrode terminal of the outer shell 21 or to connect the electrode assembly 22 and the negative electrode terminal of the outer shell 21. There can be various ways to connect the current collecting member 23 with the electrode assembly 22 and with the positive electrode terminal or the negative electrode terminal of the outer shell 21, such as welding, abutment or bonding.

[0138] Exemplarily, the battery cell 20 may include two current collecting members 23, and the electrode assembly 22 is respectively connected to the positive electrode terminal and the negative electrode terminal of the outer shell 21 through the two current collecting members 23, that is, the electrode assembly 22 is connected to the positive electrode terminal of the outer shell 21 through one current collecting member 23, and is connected to the negative electrode terminal of the outer shell 21 through another current collecting member 23, so that the positive and negative electrodes of the battery cell 20 can be output or input respectively.

[0139] In some embodiments, the battery cell 20 may further include a pressure relief mechanism, which may be mounted on the end cap 212 or the housing 211. Similarly, there may be one or more pressure relief mechanisms, which are used to release pressure inside the battery cell 20.

[0140] Illustratively, the pressure relief mechanism may be a pressure relief component such as an explosion-proof valve, an explosion-proof disk, an air valve, a pressure relief valve or a safety valve.

[0141] It should be noted that the electrode assembly 22 is the component within the battery cell 20 where the electrochemical reaction occurs. The electrode assembly 22 can have various structures, such as a wound structure formed by winding or a laminated structure formed by stacking. Similarly, the electrode assembly 22 can have various shapes, such as a cylindrical structure, an elliptical structure, or a rectangular parallelepiped structure.

[0142] In some embodiments, referring to FIG3 and further referring to FIG4 and FIG5, FIG4 is a cross-sectional view of an electrode assembly 22 provided in some embodiments of the present application, and FIG5 is a cross-sectional view of an electrode assembly 22 provided in some embodiments of the present application. The electrode assembly 22 is a wound structure formed by winding, and the electrode assembly 22 is cylindrical in shape.

[0143] The electrode assembly 22 may include two electrode sheets 221 of opposite polarity, which are wound around a central axis extending along the first direction X to form the electrode assembly 22 having a wound structure. In other words, the two electrode sheets 221 of opposite polarity are respectively the positive electrode sheet and the negative electrode sheet of the electrode assembly 22, which are wound together to form the electrode assembly 22 having a wound structure. Of course, in other embodiments, the electrode assembly 22 may also be a laminated structure formed by stacking two electrode sheets 221 of opposite polarity.

[0144] Optionally, the electrode assembly 22 may further include an isolating member 222 , which is disposed between the two pole pieces 221 to insulate and isolate the two pole pieces 221 , thereby effectively reducing the risk of short circuiting of the electrode assembly 22 during use.

[0145] Exemplarily, the material of the isolation member 222 can be various, for example, the material of the isolation member 222 can be polypropylene or polyethylene.

[0146] According to some embodiments of the present application, with reference to Figures 4 and 5, and further with reference to Figures 6, 7, and 8, Figure 6 is a schematic structural diagram of the electrode assembly 22 provided in some embodiments of the present application during the winding process, Figure 7 is a schematic structural diagram of the electrode piece 221 of the electrode assembly 22 provided in some embodiments of the present application after unfolding, and Figure 8 is a partial cross-sectional view of the electrode piece 221 provided in some embodiments of the present application after unfolding. The present application provides an electrode assembly 22, comprising two electrode pieces 221 of opposite polarity and an isolating member 222 for isolating the two electrode pieces 221, wherein the two electrode pieces 221 and the isolating member 222 are wound along a winding direction Y to form a main body 223 and two pole ears 2212. The pole lug 2212 and the main body 223 are arranged along the first direction X. The pole lug 2212 includes a plurality of pole lug portions 22121 arranged at intervals along the winding direction Y. The pole lug portions 22121 are bent relative to the first direction X. At least a portion of the plurality of pole lug portions 22121 are stacked along the first direction X, and a protrusion 22121a is formed on at least one side of the pole lug portion 22121 in its thickness direction.

[0147] Among them, the pole piece 221 may include a main body 2211 and a pole ear 2212 connected to one end of the main body 2211 in the first direction X, and the main bodies 2211 and the isolation members 222 of the two pole pieces 221 with opposite polarities are wound along the winding direction Y to form the main body 223 of the electrode assembly 22, and the winding center axis of the electrode assembly 22 extends along the first direction X, so that the pole ear 2212 of each pole piece 221 is formed at one end of the electrode assembly 22 in the first direction X, thereby making the pole ear 2212 and the main body 223 arranged along the first direction X.

[0148] For example, in FIG. 3 , the two pole pieces 221 with opposite polarities each have a pole ear 2212 . The two pole ears 2212 have opposite polarities, and the two pole ears 2212 are located at two ends of the main body 223 in the first direction X.

[0149] The main body 2211 of the electrode 221 is the area where the chemical reaction occurs within the battery cell 20. This operation primarily relies on the movement of metal ions between the main bodies 2211 of the two electrode pieces 221 of opposite polarity. 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 the first direction X. The active material layer 22112 is used to perform a chemical reaction within the battery cell 20 during use.

[0150] The pole ear portion 22121 is bent relative to the first direction X, that is, when the pole piece 221 is not wound to form the electrode assembly 22 and is in an unfolded state, the pole ear portion 22121 is a structure extending along the first direction X. After the pole piece 221 is wound to form the electrode assembly 22, the pole ear portion 22121 needs to be bent so that the pole ear portion 22121 is set at a non-zero angle with the first direction X, so that at least a part of the pole ear portions 22121 among the multiple pole ear portions 22121 can be stacked on each other along the first direction X to form the pole ear 2212.

[0151] In some embodiments, after the main bodies 2211 of the two electrode sheets 221 and the separator 222 are wound to form the main body 223 of the electrode assembly 22, the multiple lug portions 22121 of the lug 2212 can be processed by smoothing or kneading, etc., so that the lug portions 22121 are bent relative to the first direction X, and at least a portion of the multiple lug portions 22121 are stacked along the first direction X. It should be noted that after the lug portions 22121 are bent relative to the first direction X, the thickness direction Z of the lug portions can be the same as the first direction X, or can be arranged at a smaller angle to the first direction X, for example, the angle between the thickness direction Z of the lug portions and the first direction X is less than or equal to 10°. For example, in FIG5 , the thickness direction Z of the lug portions is the same as the first direction X. When the pole piece 221 is unfolded, as shown in Figure 7, the extension direction of the main body 2211 of the pole piece 221 is the winding direction Y, so that the multiple pole ear portions 22121 of the pole ear 2212 are arranged at intervals along the extension direction of the main body 2211. At the same time, after the pole piece 221 is unfolded, the first direction X, the extension direction of the main body 2211 and the thickness direction Z of the pole ear portion are mutually perpendicular structures. At this time, the thickness direction of the substrate 22111 is the same as the thickness direction Z of the pole ear portion.

[0152] Optionally, the substrate 22111 and the tab 2212 may be of an integral structure or a separate structure. If the substrate 22111 and the tab 2212 are of an integral structure, the multiple tab portions 22121 of the tab 2212 may be formed at one end of the substrate 22111 in the first direction X by cutting or other methods. If the substrate 22111 and the tab 2212 are of a separate structure, the tab 2212 may be connected to one end of the substrate 22111 in the first direction X by welding or clamping. In the embodiment where the substrate 22111 and the tab 2212 are of a separate structure, the material of the substrate 22111 may be the same as or different from the material of the tab 2212.

[0153] The pole ear 2212 of the pole piece 221 is a component of the pole piece 221 used to output or input the electrical energy of the pole piece 221. The pole ear 2212 includes a plurality of pole ear portions 22121 arranged at intervals along the winding direction Y, so that after the pole piece 221 is wound to form the electrode assembly 22, it is convenient to process the plurality of pole ear portions 22121 of the pole ear 2212 through smoothing or kneading processes, so that the plurality of pole ear portions 22121 of the pole ear 2212 can be stacked and formed at one end of the electrode assembly 22 in the first direction X, so that after the pole ear 2212 is connected to the current collecting component 23, it can output or input the positive or negative electrode of the electrode assembly 22.

[0154] The pole lug 2212 includes a plurality of pole lug portions 22121 spaced apart along the winding direction Y, that is, after the pole piece 221 is unfolded, as shown in FIG7 , the plurality of pole lug portions 22121 of the pole lug 2212 are spaced apart along the extension direction of the main body portion 2211. When the pole piece 221 is wound along the winding direction Y to form the electrode assembly 22, the extension direction of the main body portion 2211 is the same as the winding direction Y, and the plurality of pole lug portions 22121 are spaced apart along the winding direction Y.

[0155] At least a portion of the multiple pole ear portions 22121 are stacked along the first direction X, that is, after the multiple pole ear portions 22121 of the pole ear 2212 are bent relative to the first direction X through a process such as smoothing or kneading, a portion of the multiple pole ear portions 22121 can be stacked along the first direction X, or all of the pole ear portions 22121 can be stacked along the first direction X. It should be noted that after the pole piece 221 is wound to form the electrode assembly 22 of the wound structure, the extension direction of the main body 2211 is the winding direction Y, so that the multiple pole ear portions 22121 of the pole ear 2212 are arranged at intervals along the winding direction of the pole piece 221. Therefore, when the pole ear 2212 undergoes a smoothing or kneading process, the multiple pole ear portions 22121 of the pole ear 2212 are smoothed from the outer edge of the electrode assembly 22 toward the center axis of the electrode assembly 22, so that the multiple pole ear portions 22121 of the pole ear 2212 are a structure in which a part of the pole ear portion 22121 and a part of the pole ear portion 22121 are stacked along the first direction X, and another part is stacked along the first direction X with another part of the pole ear portion 22121. Of course, in some embodiments, the pole ear 2212 can also be a structure in which the multiple pole ear portions 22121 are stacked along the first direction X as a whole.

[0156] A protrusion 22121a is formed on at least one side of the pole lug 22121 in its thickness direction. That is, in the thickness direction Z of the pole lug, the pole lug 22121 may be provided with a protrusion 22121a on only one side, or may be provided with a protrusion 22121a on both sides. Similarly, the number of protrusions 22121a provided on the pole lug 22121 may be one or more. For example, in Figures 7 and 8, along the thickness direction Z of the pole lug, the protrusion 22121a is provided on only one side of the pole lug 22121, and the number of protrusions 22121a is more than one.

[0157] Optionally, the protrusion 22121a on the pole ear portion 22121 can be formed in a variety of processing methods, such as adding material to one side of the pole ear portion 22121 by welding or extrusion molding to form the protrusion 22121a on one side of the pole ear portion 22121. Alternatively, the protrusion 22121a can be pressed out from one side of the pole ear portion 22121 by stamping or rolling, and a groove 22121b is formed on the side of the pole ear portion 22121 away from the protrusion 22121a and corresponding to the protrusion 22121a. For example, in FIG8 , the protrusion 22121a is formed on one side of the pole ear portion 22121 by stamping or rolling, so that the groove 22121b is formed on the side of the pole ear portion 22121 away from the protrusion 22121a and corresponding to the protrusion 22121a. Two pole pieces 221 with opposite polarities and an isolating member 222 are wound along a winding direction Y to form a wound electrode assembly 22, so that the electrode assembly 22 has a main body 223 and two pole tabs 2212, and the pole tabs 2212 and the main body 223 are arranged along a first direction X. Among them, the pole lug 2212 is provided with a plurality of pole lug portions 22121 arranged at intervals along the winding direction Y, and the pole lug portions 22121 are bent relative to the first direction X, so that at least a portion of the plurality of pole lug portions 22121 of the pole lug 2212 can be stacked along the first direction X. By providing a protrusion 22121a on at least one side of the pole lug portion 22121 of the pole lug 2212, the thickness of the plurality of pole lug portions 22121 stacked together is increased, and the phenomenon that the plurality of pole lug portions 22121 of the pole lug have a locally smaller thickness after stacking can be alleviated, thereby improving the production quality of the pole lug 2212, and reducing the risk of the pole lug 2212 being welded through during subsequent assembly processing, thereby helping to reduce damage to the electrode assembly 22, and helping to improve the connection stability and assembly quality between the electrode assembly 22 and other components of the battery cell 20, so as to improve the production quality and usage stability of the battery cell 20 having such an electrode assembly 22.

[0158] According to some embodiments of the present application, referring to Figures 7 and 8, and further referring to Figures 9 and 10, Figure 9 is a schematic structural diagram of a pole ear portion 22121 provided in some embodiments of the present application, and Figure 10 is a front view of a pole ear portion 22121 provided in some embodiments of the present application. Along the thickness direction Z of the pole ear portion, a plurality of protrusions 22121a are formed on at least one side of the pole ear portion 22121.

[0159] Among them, multiple protrusions 22121a are formed on at least one side of the pole ear portion 22121, that is, in the thickness direction Z of the pole ear portion, the pole ear portion 22121 can be provided with multiple protrusions 22121a on only one side, or multiple protrusions 22121a can be provided on both sides of the pole ear portion 22121.

[0160] 9 and 10 , the plurality of protrusions 22121a are provided on only one side of the pole ear 22121. Providing the plurality of protrusions 22121a on only one side of the pole ear 22121 reduces the difficulty of processing the protrusions 22121a on the pole ear 22121, thereby improving production efficiency.

[0161] By arranging multiple protrusions 22121a on at least one side of the pole ear portion 22121, after the pole ear portion 22121 is bent relative to the first direction X and multiple pole ear portions 22121 are stacked along the first direction X, the area with a cavity between two stacked and adjacent pole ear portions 22121 can be effectively increased, which is beneficial to further increase the overall thickness of the pole ear 2212 in the first direction X, and can improve the uniformity of the thickness of the pole ear 2212, thereby further alleviating the phenomenon of the pole ear 2212 being welded through during subsequent assembly processing.

[0162] According to some embodiments of the present application, please continue to refer to Figures 9 and 10. Along the thickness direction Z of the pole ear portion, the projected area of ​​the pole ear portion 22121 is S1, and the sum of the projected areas of the multiple protrusions 22121a on the pole ear portion 22121 is S2, satisfying S2 / S1≥0.5.

[0163] The projection area of ​​the pole ear portion 22121 along the thickness direction Z of the pole ear portion is S1, that is, the area of ​​the region defined by the projection of the pole ear portion 22121 in the thickness direction Z of the pole ear portion is S1.

[0164] The sum of the projected areas of the multiple protrusions 22121a on the tab 22121 along the thickness direction Z of the tab is S2, i.e., the sum of the areas defined by the projections of each protrusion 22121a along the thickness direction Z of the tab is S2. It should be noted that if the tab 22121 is provided with protrusions 22121a on only one side, S2 is the sum of the projected areas of the multiple protrusions 22121a on one side of the tab 22121 along the thickness direction Z of the tab; if the multiple protrusions 22121a are provided on both sides of the tab 22121, S2 is the sum of the projected areas of the multiple protrusions 22121a on both sides of the tab 22121 along the thickness direction Z of the tab.

[0165] Illustratively, the sum S2 of the projected areas of the plurality of protrusions 22121 a on the pole ear portion 22121 may 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 pole ear portion 22121 .

[0166] It should be noted that when obtaining S1 and S2, that is, when measuring the projection area S1 of the pole ear 22121 and the sum of the projection areas S2 of the multiple protrusions 22121a on the pole ear 22121, it is necessary to first unfold the pole piece 221 and then measure (as shown in Figure 7) to obtain S1 and S2, that is, S1 is the projection surface of the pole ear 22121 in the thickness direction Z of the pole ear when the pole piece 221 is in the unfolded state, and S2 is the sum of the projection areas of the multiple protrusions 22121a on the pole ear 22121 in the thickness direction Z of the pole ear when the pole piece 221 is in the unfolded state.

[0167] By setting the sum of the projected areas of the multiple protrusions 22121a on the pole ear portion 22121 in the thickness direction Z of the pole ear portion to be greater than or equal to half of the projected area of ​​the pole ear portion 22121 in the thickness direction Z of the pole ear portion, the area occupied by the multiple protrusions 22121a on the pole ear portion 22121 is half or more of the pole ear portion 22121, so that there is a sufficient area on the pole ear portion 22121 to be provided with the protrusions 22121a, so that after the multiple pole ear portions 22121 of the pole ear 2212 are stacked along the first direction X, the pole ear 2212 has a sufficient thickness, and the uniformity of the thickness of the pole ear 2212 can be effectively improved, so as to reduce the risk of the pole ear 2212 being welded through during the subsequent assembly process.

[0168] According to some embodiments of the present application, as shown in Figures 8 and 10 , the tab portion 22121 includes a main body region 22121c that does not overlap with a 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. Along the thickness direction Z of the tab portion, the maximum dimension of the tab portion 22121 is D1, and the thickness of the main body region 22121c is D2, satisfying 2≤D1 / D2≤8.

[0169] Among them, the pole ear portion 22121 includes a main body area 22121c which does not overlap with the projection of the protrusion 22121a in the thickness direction Z of the pole ear portion, that is, the area of ​​the pole ear portion 22121 where the protrusion 22121a is not formed is the main body area 22121c, so that the projection of the main body area 22121c in the thickness direction Z of the pole ear portion and the projection of the protrusion 22121a in the thickness direction Z of the pole ear portion do not intersect with each other, that is, the protrusion 22121a protrudes from one side of the main body portion 2211 in the thickness direction Z of the pole ear portion.

[0170] The maximum dimension of the pole ear portion 22121 is D1, and the thickness of the main area 22121c is D2, satisfying 2≤D1 / D2≤8, that is, the maximum thickness of the pole ear portion 22121 in its thickness direction is 2 to 8 times the wall thickness of the main area 22121c itself, that is, the maximum thickness of the pole ear portion 22121 after the protrusion 22121a is formed by a stamping or rolling process is 2 to 8 times the thickness of the pole ear portion 22121 before the stamping or rolling process is performed.

[0171] Exemplarily, the maximum dimension D1 of the tab portion 22121 may 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.

[0172] It should be noted that if the pole piece 221 is a positive pole piece, the pole ear 2212 corresponding to the pole piece 221 is a positive pole ear, and the thickness of the pole ear portion 22121 of the positive pole ear before stamping or rolling to form the protrusion 22121a is 10μm-16μm; if the pole piece 221 is a negative pole piece, the pole ear 2212 corresponding to the pole piece 221 is a negative pole ear, and the thickness of the pole ear portion 22121 of the negative pole ear before stamping or rolling to form the protrusion 22121a is 4μm-10μm.

[0173] The pole ear portion 22121 has a main body area 22121c that does not overlap with the projection of the protrusion 22121a in the thickness direction Z of the pole ear portion, and the protrusion 22121a protrudes from the main body area 22121c in the thickness direction Z of the pole ear portion, that is, the main body area 22121c of the pole ear portion 22121 is the area of ​​the pole ear portion 22121 where the protrusion 22121a is not provided. By setting the maximum size of the pole ear portion 22121 in the thickness direction Z of the pole ear portion to twice the thickness of the main body area 22121c That is to say, the maximum thickness of the pole ear portion 22121 after being provided with the protrusion 22121a is 2 times to 8 times the thickness of the main area 22121c of the pole ear portion 22121, so that after the pole ear portion 22121 is bent relative to the first direction X, the thickness of the multiple pole ear portions 22121 of the pole ear 2212 stacked on each other along the first direction X can be effectively increased, so as to achieve an increase in the thickness of the pole ear 2212, and further effectively alleviate the phenomenon of the pole ear 2212 being welded through during the subsequent assembly process.

[0174] According to some embodiments of the present application, referring to FIG. 7 , FIG. 9 and FIG. 10 , the pole ear portion 22121 is formed with multiple rows of protrusions 22121 a , and each row of protrusions 22121 a includes multiple protrusions 22121 a arranged at intervals.

[0175] The pole piece 22121 is formed with multiple rows of protrusions 22121a, each row of protrusions 22121a including multiple protrusions 22121a spaced apart from each other. That is, the multiple protrusions 22121a on the pole piece 22121 are arranged in an array, so that the multiple protrusions 22121a are arranged in multiple rows and columns. Before the pole piece 221 is wound, that is, in the unfolded structure of the pole piece 221, the multiple protrusions 22121a in each row can be spaced apart along the first direction X, or can be spaced apart along the winding direction Y (the extension direction of the main body 2211).

[0176] In the pole ear portion 22121 of this structure, the shape of the protrusion 22121a can be various. For example, in Figures 9 and 10, the protrusion 22121a is a hemispherical structure. Referring to Figures 11 and 12, Figure 11 is a schematic structural diagram of the pole ear portion 22121 provided in some other embodiments of the present application, and Figure 12 is a front view of the pole ear portion 22121 provided in some other embodiments of the present 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.

[0177] By arranging multiple rows of protrusions 22121a on the pole ear portion 22121, and each row of protrusions 22121a includes multiple protrusions 22121a arranged at intervals, so that the multiple protrusions 22121a on the pole ear portion 22121 are arranged in an array, so that after the multiple pole ear portions 22121 of the pole ear 2212 are stacked along the first direction X, the area with a cavity between two stacked and adjacent pole ear portions 22121 can be effectively increased, which is beneficial to further improve the overall thickness of the pole ear 2212 in the first direction X, and can effectively improve the uniformity of the thickness of the pole ear 2212, so as to reduce the phenomenon of the pole ear 2212 being welded through during the subsequent assembly process.

[0178] In some embodiments, as shown in FIG. 10 and FIG. 12 , the maximum dimension of the protrusion 22121 a in a direction perpendicular to the thickness direction Z of the tab portion is W1 , satisfying 0.3 mm ≤ W1 ≤ 2 mm.

[0179] The maximum dimension of the protrusion 22121a in a direction perpendicular to the thickness direction Z of the tab is W1. That is, in any direction within a plane perpendicular to the thickness direction Z of the tab, the maximum width of the protrusion 22121a is W1. In other words, the maximum width of the protrusion 22121a in its radial direction within a plane perpendicular to the thickness direction Z of the tab is W1. For example, if the protrusion 22121a has a hemispherical or cylindrical structure, W1 is the diameter of the protrusion 22121a; if the protrusion 22121a has a square columnar structure, W1 is the length of the diagonal of the protrusion 22121a.

[0180] Exemplarily, the maximum dimension W1 of the protrusion 22121a in a direction perpendicular to the thickness direction Z of the tab portion may be 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm or 2 mm, etc.

[0181] By setting the maximum dimension of the protrusion 22121a in the direction perpendicular to the thickness direction Z of the pole ear portion to 0.3mm to 3mm, that is, the maximum dimension of the protrusion 22121a in its radial direction is 0.3mm to 3mm, on the one hand, it can alleviate the phenomenon that the processing difficulty is too great due to the small size of the protrusion 22121a, so as to reduce the processing difficulty of the pole ear portion 22121; on the other hand, it can alleviate the phenomenon that the number of multiple protrusions 22121a on the pole ear portion 22121 is limited due to the large size of the protrusion 22121a. In addition, in an embodiment where a groove 22121b is provided on the side of the pole ear portion 22121 away from the protrusion 22121a and corresponding to the position of the protrusion 22121a, the adoption of such a structure can effectively alleviate the phenomenon that the protrusion 22121a and the groove 22121b of two adjacent pole ear portions 22121 of the pole ear 2212 overlap and offset each other after the multiple pole ear portions 22121 of the pole ear 2212 are stacked on each other due to the excessive size of the protrusion 22121a, thereby providing a cavity between the two stacked and adjacent pole ear portions 22121 to increase the overall thickness of the pole ear 2212.

[0182] According to some embodiments of the present application, referring to Figures 13 and 14, Figure 13 is a schematic structural diagram of a pole ear portion 22121 provided in some further embodiments of the present application, and Figure 14 is a front view of a pole ear portion 22121 provided in some further embodiments of the present application. The pole ear portion 22121 is formed with a plurality of protrusions 22121a arranged at intervals, with the ends of the protrusions 22121a extending to the ends of the pole ear portion 22121 in a direction perpendicular to the arrangement direction of the plurality of protrusions 22121a.

[0183] The arrangement direction of the plurality of protrusions 22121 a refers to a direction in which the plurality of protrusions 22121 a are arranged in sequence and at intervals in a plane perpendicular to the thickness direction Z of the electrode ear portion.

[0184] The ends of the protrusion 22121a extend to the ends of the pole lug 22121 in a direction perpendicular to the arrangement direction of the multiple protrusions 22121a. In other words, the protrusion 22121a is a strip-shaped structure, and the ends of the protrusion 22121a extend to the ends of the pole lug 22121 in a direction perpendicular to the arrangement direction of the multiple protrusions 22121a, so that the multiple protrusions 22121a are arranged in a spaced-apart arrangement along the width direction of the protrusion 22121a. It should be noted that when the pole piece 221 is in the unfolded state, the extension direction of the protrusion 22121a in the strip structure can be along the first direction X or along the winding direction Y (the extension direction of the main body 2211).

[0185] For example, in FIG. 13 and FIG. 14 , the protrusion 22121 a is a strip-shaped structure with a rectangular cross-section. Of course, in other embodiments, the protrusion 22121 a may also be a strip-shaped structure with a semicircular, pentagonal, or other cross-section.

[0186] By forming a plurality of protrusions 22121a arranged at intervals on the pole ear portion 22121, and the two ends of the protrusion 22121a extend to the two ends of the pole ear portion 22121, a structure in which a plurality of protrusions 22121a are arranged on the pole ear portion 22121 is realized. The use of this structure is conducive to reducing the difficulty of arranging the protrusions 22121a on the pole ear portion 22121, thereby improving the processing efficiency of the pole ear portion 22121.

[0187] In some embodiments, as shown in FIG. 14 , along the arrangement direction of the plurality of protrusions 22121 a , the width of the protrusions 22121 a is W2 , satisfying 0.3 mm ≤ W2 ≤ 2 mm.

[0188] The width of the protrusion 22121a is W2, that is, in the arrangement direction of the plurality of protrusions 22121a, the maximum size of the protrusion 22121a is W2.

[0189] Exemplarily, the width W2 of the protrusion 22121a can be 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm or 2 mm, etc.

[0190] 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 size 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 great due to the small width of the protrusion 22121a, so as to reduce the processing difficulty of the pole ear 22121; on the other hand, it can alleviate the phenomenon that the number of multiple protrusions 22121a on the pole ear 22121 is limited due to the excessive width of the protrusion 22121a. In addition, in an embodiment where a groove 22121b is provided on the side of the pole ear portion 22121 away from the protrusion 22121a and corresponding to the position of the protrusion 22121a, the use of this structure can effectively alleviate the phenomenon that the protrusion 22121a and the groove 22121b of two adjacent pole ear portions 22121 of the pole ear 2212 overlap and offset each other after the multiple pole ear portions 22121 of the pole ear 2212 are stacked on each other due to the excessive width of the protrusion 22121a, thereby allowing a cavity to exist between the two stacked and adjacent pole ear portions 22121 to meet the requirement that the pole ear 2212 has sufficient thickness after being smoothed.

[0191] According to some embodiments of the present application, referring to Figures 15 and 16 , Figure 15 is a partial cross-sectional view of an unfolded pole piece 221 provided in other embodiments of the present application, and Figure 16 is a cross-sectional view of a pole piece 22121 of a pole piece 221 provided in other embodiments of the present application. Along the thickness direction Z of the pole piece 22121, the pole piece 22121 may include a plurality of stacked foils 22121d. 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 within the recess 22121f of the other foil 22121d. Along the thickness direction Z of the pole piece 22121, the protrusion 22121e located on one side of the pole piece 22121 is a protrusion 22121a.

[0192] In the thickness direction Z of the pole lug portion, the pole lug portion 22121 includes a plurality of foils 22121d stacked together, that is, the pole lug portion 22121 is composed of a plurality of foils 22121d, and the plurality of foils 22121d are stacked together along the thickness direction Z of the pole lug portion to form the pole lug portion 22121 of the pole lug 2212. For example, in Figures 15 and 16, the pole lug portion 22121 may include two foils 22121d, one of which is connected to the main body 2211, and the other foil 22121d is stacked along the thickness direction Z of the pole lug portion on one side of the foil 22121d connected to the main body 2211. Of course, in other embodiments, the pole lug 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 material 22121d.

[0193] A convex portion 22121e is formed on one side of the foil 22121d, and a concave portion 22121f is formed on the other side at a position corresponding to the convex portion 22121e. That is, in the thickness direction Z of the pole ear portion, a convex portion 22121e protruding from the foil 22121d is formed on one side of the foil 22121d, and a concave portion 22121f is formed on the other side at a position corresponding to the convex portion 22121e, so that the convex portion 22121e and the concave portion 22121f are arranged one by one in the thickness direction Z of the pole ear portion.

[0194] In two adjacent foils 22121d, the convex portion 22121e of one foil 22121d is accommodated in the concave portion 22121f of the other foil 22121d. That is, along the thickness direction Z of the pole ear portion, in the two stacked and adjacent foils 22121d, the convex portion 22121e of one foil 22121d and the concave portion 22121b of the other foil 22121d are arranged in a one-to-one correspondence, so that the convex portion 22121e of one foil 22121d can be embedded in the concave portion 22121b of the other foil 22121d, so that the two foils 22121d can fit tightly.

[0195] Along the thickness direction Z of the pole ear portion, the convex portion 22121e located on one side of the pole ear portion 22121 is the protrusion 22121a, that is, the convex portion 22121e of the foil material 22121d located on one side among the multiple foil materials 22121d of the pole ear portion 22121 is the protrusion 22121a on one side of the pole ear portion 22121, and correspondingly, the concave portion 22121f of the foil material 22121d located on the other side among the multiple foil materials 22121d of the pole ear portion 22121 is the groove 22121b on the other side of the pole ear portion 22121.

[0196] For example, the multiple foils 22121d of the tab portion 22121 may be connected in various ways, such as snap-fitting, bonding, or welding.

[0197] By setting the pole ear portion 22121 as a structure in which multiple foil materials 22121d are stacked, and a convex portion 22121e is formed on one side of the foil material 22121d, and a concave portion 22121f is formed on the other side, so that after the multiple foil materials 22121d are stacked, the convex portions 22121e and the concave portions 22121f of two adjacent foil materials 22121d can be embedded in each other, so that a convex portion 22121a is formed on one side of the pole ear portion 22121 in the thickness direction Z of the pole ear portion. The pole ear portion 22121 adopting this structure can effectively increase the thickness and structural strength of the pole ear portion 22121 itself, so that after the multiple pole ear portions 22121 of the pole ear 2212 are stacked along the first direction X, the overall thickness and structural strength of the pole ear 2212 can be further increased, so as to further reduce the risk of the pole ear 2212 being welded through during the subsequent assembly process.

[0198] According to some embodiments of the present application, as shown in FIG16 , multiple foils 22121d are welded together to form convex portions 22121e and concave portions 22121f on the foils 22121d. In other words, the convex portions 22121e and concave portions 22121f are correspondingly formed at the welded locations during the welding process of the multiple foils 22121d. That is, the convex portions 22121e and concave portions 22121f on the foils 22121d are structures formed by welding the multiple foils 22121d.

[0199] For example, multiple foils 22121d are connected by ultrasonic roller welding to form convex portions 22121e and concave portions 22121f at the welded locations of the foils 22121d. Specific connection methods for ultrasonic roller welding can be found in related art and will not be described in detail here.

[0200] Welding is used to connect multiple stacked foils 22121d, and protrusions 22121e and recesses 22121f are formed at positions where the multiple foils 22121d are welded to each other. This is beneficial to improving the connection strength and stability between the multiple foils 22121d on the one hand, and is beneficial to reducing the processing difficulty of forming the recesses 22121f and protrusions 22121e on the foil 22121d on the other hand, so as to optimize the production rhythm of the pole piece 221, thereby effectively improving the production efficiency of the pole piece 221.

[0201] According to some embodiments of the present application, as shown in Figures 5, 15, and 16, a pole piece 221 may include a main body 2211, a plurality of pole lugs 22121 connected to the main body 2211, and the main bodies 2211 and separators 222 of two pole pieces 221 are wound along a 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 that are stacked. 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. The second foil 22121h is disposed separately from the substrate 22111.

[0202] Among them, the multiple pole ear portions 22121 of the pole ear 2212 are connected to one end of the main body 2211 in the first direction X. When the pole piece 221 is in the unfolded state, the pole ear 2212 and the main body 2211 are arranged along the first direction X, and the multiple pole ear portions 22121 of the pole ear 2212 are spaced apart along the extension direction of the main body 2211; after the pole piece 221 is wound to form the electrode assembly 22, and the pole ear portion 22121 is bent relative to the first direction X, the multiple pole ear portions 22121 of the pole ear 2212 are spaced apart along the winding direction Y, and the pole ear portion 22121 is connected to one end of the main body 2211 in the first direction X, and is arranged at a non-zero angle with the main body 2211.

[0203] An active material layer 22112 is provided on at least one side of the substrate 22111. That is, the active material layer 22112 may be provided on only one side of the substrate 22111, or on both sides of the substrate 22111. For example, in FIG15 , the active material layer 22112 is provided on both sides of the substrate 22111.

[0204] The active material layer 22112 is the area within the battery cell 20 where chemical reactions occur. It primarily operates by the movement of metal ions between the active material layers 22112 of the two electrode sheets 221. Of course, in some embodiments, the substrate 22111 may also be coated with an insulating protective layer. This insulating protective layer is disposed along the first direction X at one or both ends of the active material layer 22112 to protect and separate the active material layer 22112. Of course, in other embodiments, the insulating protective layer may not be disposed at one end of the active material layer 22112 in the first direction X, meaning that only the active material layer 22112 is coated on the substrate 22111.

[0205] It should be noted that if the electrode 221 is a positive electrode, the material of the active material layer 22112 of the main body 2211 corresponding to the electrode 221 can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide, etc.; if the electrode 221 is a negative electrode, the material of the active material layer 22112 of the main body 2211 corresponding to the electrode 221 can be carbon or silicon, etc.

[0206] 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 by cutting and processing on the substrate 22111. Of course, in other embodiments, the first foil 22121g and the substrate 22111 may 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 may also be indirectly connected, for example, the first foil 22121g and the substrate 22111 are indirectly connected via other conductive components.

[0207] Illustratively, one end of the first foil 22121 g in a direction perpendicular to the thickness direction Z of the tab portion is connected to one end of the base material 22111 in the first direction X.

[0208] It should be noted that after the pole piece 221 is unfolded, the thickness direction Z of the pole ear portion and the first direction X are perpendicular to each other, then one end of the first foil 22121g in a direction perpendicular to the thickness direction Z of the pole ear portion is connected to one end of the substrate 22111 in the first direction X, that is, one end of the first foil 22121g in the first direction X is connected to one end of the substrate 22111 in the first direction X (see Figure 15).

[0209] The second foil 22121h is provided separately from the substrate 22111, that is, the second foil 22121h and the substrate 22111 are two independent components. For example, in Figure 15, the second foil 22121h is stacked and connected to one side of the first foil 22121g in the thickness direction Z of the electrode ear. It should be noted that in other embodiments, in the thickness direction Z of the electrode ear, the first foil 22121g may be provided with the second foil 22121h only on one side or on both sides, and the number of second foils 22121h provided on one side of the first foil 22121g may be one or more.

[0210] The multiple foils 22121d include a first foil 22121g that is 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 on the area, and 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, so as to achieve an increase in the thickness and structural strength of the electrode ear 22121. The electrode 221 with this structure can effectively reduce the process difficulty of connecting the electrode ear 22121 to the substrate 22111, which is conducive to improving the production efficiency of the electrode assembly 22.

[0211] According to some embodiments of the present application, referring to FIG5 and FIG15 , 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 provided in the coating area 22111a , and the spacer area 22111b connects the coating area 22111a and the first foil 22121g .

[0212] The spacer region 22111b of the substrate 22111 is an 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 is connected between the coating region 22111a and the first foil 22121g in the first direction X.

[0213] In FIG15 , the spacer 22111b is a blank area on the substrate 22111. It should be noted that, in some embodiments, the spacer 22111b on the substrate 22111 that is not coated with the active material layer 22112 may also be coated with an insulating protective layer, etc., to protect the active material layer 22112. Of course, in other embodiments, the substrate 22111 of the main body 2211 may not be provided with the spacer 22111b, that is, the first foil 22121g 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 first foil 22121g is connected to one end of the substrate 22111.

[0214] By arranging a coating area 22111a coated with an active material layer 22112 and a spacer area 22111b not coated with an active material layer 22112 on the substrate 22111, the first foil 22121g of the pole ear 22121 can be connected to the coating area 22111a through the spacer area 22111b, so that the pole ear 22121 and the active material layer 22112 are spaced apart in the first direction X. On the one hand, the electrode assembly 22 with such a structure can isolate the stress generated by the pole ear 22121 during the bending process relative to the first direction X through the spacer area 22111b, so as to reduce the risk of fracture of the active material layer 22112 arranged on the coating area 22111a. On the other hand, in the subsequent welding of the pole ear 2212 with other components, the impact on the active material layer 22112 caused by the welding process can be reduced, thereby alleviating the phenomenon of damage to the active material layer 22112, which is beneficial to improving the production quality of the electrode assembly 22.

[0215] According to some embodiments of the present application, as shown in FIG. 16 , along the thickness direction Z of the tab portion, the thickness of the first foil 22121 g is D3 , and the thickness of the second foil 22121 h is D4 , satisfying 0.5≤D3 / D4≤2.

[0216] Among them, 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 where the protrusion 22121e and the recess 22121f are not formed, that is, the thickness D3 of the first foil 22121g is the thickness of the first foil 22121g before the protrusion 22121e and the recess 22121f are formed.

[0217] 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 protrusion 22121e and the recess 22121f are not formed, that is, the thickness D4 of the second foil 22121h is the thickness of the second foil 22121h before the protrusion 22121e and the recess 22121f are formed.

[0218] For example, the thickness D3 of the first foil 22121g may be 0.5 times, 0.6 times, 0.75 times, 0.8 times, 1 times, 1.2 times, 1.5 times, or 2 times the thickness D4 of the second foil 22121h.

[0219] During the experiment, a first foil 22121g with a thickness of 12 μm was selected for the experiment, and the second foil 22121h was set to different thicknesses for the experiment. The effects of the thickness ratio of the first foil 22121g to the second foil 22121h on the welding assembly of the first foil 22121g and the second foil 22121h under different conditions were measured. The experimental results are as follows:

[0220] It can be seen from the above experimental data 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 crack during the welding process, thereby generating debris, which cannot meet the requirements of mutual welding and assembly of the first foil 22121g and the second foil 22121h. 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 cracks during the mutual 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 crack during the welding process, thereby generating debris, which cannot meet the requirements of mutual welding and assembly of the first foil 22121g and the second foil 22121h. 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 will crack during the mutual 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 be 0.5 to 2 times the thickness of the second foil 22121h, that is, the thickness of the first foil 22121g is 0.5 to 2 times the thickness of the second foil 22121h, the difficulty in assembling the first and second foils 22121g, 22121h, caused by the large difference in thickness between the first and second foils 22121g and 22121h can be alleviated, thereby reducing the difficulty in processing the tab portion 22121 of this structure. In addition, on the one hand, the problem of damage to the second foil 22121h during the welding process caused by the first foil 22121g being too thick compared to the second foil 22121h can be alleviated, and on the other hand, the problem of damage to the first foil 22121g during the welding process caused by the second foil 22121h being too thick compared to the first foil 22121g can be alleviated.

[0223] According to some embodiments of the present application, as shown in Figures 15 and 16 , along a direction perpendicular to the thickness direction Z of the electrode ear portion, an end of the second foil 22121h closer to the substrate 22111 does not extend beyond the first foil 22121g and is connected to an end of the substrate 22111. It should be noted that when the electrode 221 is in an unfolded state, in the first direction X, an end of the second foil 22121h closer to the substrate 22111 does not extend beyond the first foil 22121g and is connected to an end of the substrate 22111.

[0224] The end of the second foil 22121h closer to the substrate 22111 does not extend beyond the end of the first foil 22121g connected to the substrate 22111. In other words, the end of the first foil 22121g connected to the substrate 22111 can be flush with the second foil 22121h or extend beyond the second foil 22121h. For example, in Figures 15 and 16, the end of the first foil 22121g connected to the substrate 22111 extends beyond the end of the second foil 22121h closer to the substrate 22111.

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

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

[0227] According to some embodiments of the present application, as shown in Figures 15 and 16 , along a direction perpendicular to the thickness direction Z of the pole ear portion, 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, L≤2mm. It should be noted that when the pole piece 221 is in the unfolded state, L is the distance in 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] Among them, 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 with each other. 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 2 mm.

[0229] It should be noted that 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 can be such that 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, with the first foil 22121g extending beyond the second foil 22121h by less than or equal to 2 mm. Alternatively, the end of the second foil 22121h away from the substrate 22111 extends beyond the end of the first foil 22121g away from the substrate 22111, with the second foil 22121h extending beyond the first foil 22121g by 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 FIG. 16 , one end of the first foil 22121 g away from the substrate 22111 exceeds one end of the second foil 22121 h away from the substrate 22111 , and a dimension of the portion of the first foil 22121 g that exceeds the second foil 22121 h 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 electrode ear portion to be less than or equal to 2 mm, that is, the dimension of the end of the first foil 22121g away from the substrate 22111 exceeding the end of the second foil 22121h away from the substrate 22111 is less than or equal to 2 mm, or the end of the second foil 22121h away from the substrate 22111 exceeds the first foil 22121g. The dimension of the end of the foil 22121g away from the substrate 22111 is less than or equal to 2 mm, thereby alleviating the phenomenon that the first foil 22121g exceeds the second foil 22121h too much or the second foil 22121h exceeds the first foil too much due to the length of the first foil 22121g or the length of the second foil 22121h being too large, resulting in the ear portion 22121 being too long or being inserted upside down into the electrode assembly 22, which is beneficial to improving the production quality and use 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. In other words, the first foil 22121g and the second foil 22121h are made of the same material.

[0233] Illustratively, the material of the first foil 22121g and the material of 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 be made of the same material, on the one hand, the polarity of the pole ear 22121 can be stabilized, and on the other hand, the difficulty of connecting the first foil 22121g and the second foil 22121h can be reduced.

[0235] According to some embodiments of the present application, as shown in FIG5 , FIG7 , and FIG8 , a pole piece 221 may include a main body 2211 , a plurality of pole lugs 22121 connected to one end of the main body 2211 in a first direction X, and the main bodies 2211 and separators 222 of two pole pieces 221 are wound along a 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 region 22111a and a spacer region 22111b . The coating region 22111a and the spacer region 22111b are arranged along the first direction X. The active material layer 22112 is disposed on the coating region 22111a , and the spacer region 22111b connects the coating region 22111a and the pole lug 22121 .

[0236] Among them, the multiple pole ear portions 22121 of the pole ear 2212 are connected to one end of the main body 2211 in the first direction X. When the pole piece 221 is in the unfolded state, the pole ear 2212 and the main body 2211 are arranged along the first direction X, and the multiple pole ear portions 22121 of the pole ear 2212 are spaced apart along the extension direction of the main body 2211; after the pole piece 221 is wound to form the electrode assembly 22, and the pole ear portion 22121 is bent relative to the first direction X, the multiple pole ear portions 22121 of the pole ear 2212 are spaced apart along the winding direction Y, and the pole ear portion 22121 is connected to one end of the main body 2211 in the first direction X, and is 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 be provided with an active material layer 22112 on one side or on both sides. For example, in FIG8 , the substrate 22111 is provided with an active material layer 22112 on both sides.

[0238] The spacer region 22111b of the substrate 22111 is an area on the substrate 22111 that is not coated with the active material layer 22112. The coated region 22111a and the spacer region 22111b are arranged along the first direction X, and the spacer region 22111b connects the coated region 22111a and the electrode ear portion 22121. That is, in the first direction X, the spacer region 22111b is connected between the coated region 22111a and the electrode ear portion 22121. It should be noted that in this embodiment, the electrode ear portion 22121 may be a structure including only one foil material 22121d, or the electrode ear portion 22121 may be a structure including multiple foil materials 22121d arranged in a stacked manner.

[0239] In FIG8 , the spacer 22111b is a blank area on the substrate 22111. It should be noted that, in some embodiments, the spacer 22111b on the substrate 22111 that is not coated with the active material layer 22112 may also be coated with an insulating protective layer, etc., to protect the active material layer 22112. Of course, in other embodiments, the spacer 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 arranging a coating area 22111a coated with an active material layer 22112 and a spacer area 22111b not coated with the active material layer 22112 on the substrate 22111, the pole ear portion 22121 can be connected to the coating area 22111a through the spacer area 22111b, so that the pole ear portion 22121 and the active material layer 22112 are spaced apart in the first direction X. The electrode assembly 22 with this structure can, on the one hand, isolate the stress generated by the pole ear portion 22121 during the bending process relative to the first direction X through the spacer area 22111b, so as to reduce the risk of fracture of the active material layer 22112 arranged on the coating area 22111a. On the other hand, in the subsequent welding of the pole ear 2212 with other components, it can reduce the impact of the welding process on the active material layer 22112, thereby alleviating the phenomenon of damage to the active material layer 22112, and thus is conducive to improving the production quality of the electrode assembly 22.

[0241] In some embodiments, as shown in FIG. 5 , the tab portion 22121 and the spacer 22111 b are integrally formed.

[0242] The electrode ear portion 22121 and the spacer region 22111b are integrally formed, that is, the electrode ear portion 22121 includes only one foil material 22121d, and the electrode ear portion 22121 is a structure formed by cutting and processing on the substrate 22111. Of course, in other embodiments, the electrode ear portion 22121 and the substrate 22111 may also be separate structures. For example, the electrode ear portion 22121 is connected to one end of the substrate 22111 in the first direction X by welding or other methods.

[0243] It should be noted that in an embodiment where the spacer area 22111b is not provided on the substrate 22111 of the main body 2211, the pole ear portion 22121 may also be a structure integrally formed with the substrate 22111, that is, the pole ear portion 22121 is integrally formed with the coating area 22111a of the substrate 22111.

[0244] By setting the pole ear portion 22121 as a structure integrally formed with the spacer area 22111b of the substrate 22111, the pole ear portion 22121 can be a part of the substrate 22111 during the actual production process. After reserving an area on the substrate 22111 where the active material layer 22112 is not set, the pole ear portion 22121 can be set on the area, so as to reduce the process difficulty of connecting the pole ear portion 22121 to the substrate 22111, which is beneficial to improving the production efficiency of the electrode assembly 22.

[0245] According to some embodiments of the present application, as shown in FIG5 and FIG8 , along the thickness direction Z of the pole ear portion, a groove 22121 b is formed on a side of the pole ear portion 22121 away from the protrusion 22121 a and corresponding to the position of the protrusion 22121 a .

[0246] Among them, along the thickness direction Z of the pole ear portion, a groove 22121b is formed on the side of the pole ear 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 pole ear 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 arranged one by one in the thickness direction Z of the pole ear portion.

[0247] For example, the ear portion 22121 of this structure can be processed in a variety of ways, such as stamping or rolling.

[0248] By providing a groove 22121b on the side of the pole ear 22121 away from the protrusion 22121a and corresponding to the position of the protrusion 22121a, the pole ear 22121 with this structure can be formed with the protrusion 22121a on the pole ear 22121 through processes such as stamping or rolling. On the one hand, it is beneficial to reduce the processing difficulty of the pole ear 22121 and to improve the processing efficiency of the pole ear 22121. On the other hand, there is no need to provide the protrusion 22121a on one side of the pole ear 22121 by adding material, which is beneficial to reducing the production cost of the pole ear 22121 and reducing the weight of the pole ear 22121.

[0249] According to some embodiments of the present application, referring to Figures 5 and 8, and further referring to Figure 17, Figure 17 is a cross-sectional view of a plurality of tab portions 22121 of a tab 2212 of an electrode assembly 22 provided in some embodiments of the present application after stacking. Along the first direction X, in two adjacent tab portions 22121, the protrusion 22121a of one tab portion 22121 is staggered with the groove 22121b of the other tab portion 22121.

[0250] Among them, in two adjacent pole ear portions 22121, the protrusion 22121a of one pole ear portion 22121 and the groove 22121b of the other pole ear portion 22121 are staggered, that is, in two adjacent pole ear portions 22121, the protrusion 22121a of one pole ear portion 22121 and the groove 22121b of the other pole ear portion 22121 are not aligned in the first direction X.

[0251] By setting the protrusion 22121a of one pole ear portion 22121 and the groove 22121b of the other pole ear portion 22121 in two adjacent pole ear portions 22121 in the first direction X to a mutually staggered structure, the phenomenon of mutual offsetting after the protrusion 22121a and the groove 22121b overlap can be effectively alleviated, so that the pole ear 2212 has sufficient thickness in the first direction X, which is beneficial to reduce the risk of the pole ear 2212 of the electrode assembly 22 being welded through during the subsequent assembly process.

[0252] In some embodiments, as shown in FIG. 17 , along the first direction X, the thickness of the tab 2212 is D5 , satisfying 0.2 mm ≤ D5 ≤ 2.5 mm.

[0253] Among them, the thickness of the pole ear 2212 is D5, that is, after the multiple pole ear portions 22121 of the pole ear 2212 are bent relative to the first direction X through smoothing or kneading processes and stacked on one end of the main body 223 of the electrode assembly 22 in the first direction X, the size of the pole ear 2212 in the first direction X is D5.

[0254] Illustratively, the thickness D5 of the tab 2212 may be 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.8 mm, 1 mm, 1.5 mm, 2 mm, or 2.5 mm.

[0255] By setting the thickness of the pole tab 2212 in the first direction X to 0.2 mm to 2.5 mm, on the one hand, the risk of the pole tab 2212 being welded through due to the thickness of the pole tab 2212 being too small can be alleviated, thereby reducing the risk of the electrode assembly 22 being damaged during the subsequent assembly process. On the other hand, the phenomenon of the pole tab 2212 occupying too much space due to the thickness of the pole tab 2212 being too large can be alleviated, which is conducive to optimizing the internal space of the battery cell 20 having such an electrode assembly 22, thereby improving the energy density of the battery cell 20.

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

[0257] The polarities of the two electrode sheets 221 are opposite, that is, the two electrode sheets 221 are respectively the positive electrode sheet and the negative electrode sheet of the electrode assembly 22 .

[0258] The two pole ears 2212 are respectively arranged at the two ends of the main body 223 of the electrode assembly 22, that is, the pole ears 2212 of the two pole pieces 221 with opposite polarities are respectively formed at the two ends of the electrode assembly 22 in the first direction X, so that the positive pole ear and the negative pole ear are respectively formed at the two ends of the electrode assembly 22 in the first direction X to output or input the positive and negative poles of the electrode assembly 22.

[0259] By respectively arranging the two pole ears 2212 of the electrode assembly 22 at the two ends of the main body 223 of the electrode assembly 22 in the first direction X, so that the two pole ears 2212 are respectively formed at the two ends of the electrode assembly 22 in the first direction X, it is convenient to subsequently assemble the electrode assembly 22, which is beneficial to reduce the difficulty of assembling the battery cell 20 with such an electrode assembly 22, and can reduce the interference or mutual contact between the two pole ears 2212, thereby helping to reduce the risk of short circuit of the electrode assembly 22.

[0260] In some embodiments, as shown in Figures 3, 4, and 5, 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 configuring the electrode assembly 22 to be a cylindrical structure, subsequent processing to form a cylindrical battery cell 20 is facilitated.

[0262] According to some embodiments of the present application, as shown in FIG3 , an embodiment of the present application further provides a battery cell 20 , comprising a housing 21 and an electrode assembly 22 of any of the above solutions, wherein the electrode assembly 22 is accommodated in the housing 21 .

[0263] The outer shell 21 may include a shell 211 and an end cover 212 . The shell 211 is a hollow structure with an opening 2111 on one side. The end cover 212 closes the opening 2111 of the shell 211 to form a sealed space for accommodating the electrode assembly 22 .

[0264] The housing 211 may be in various shapes, such as a cylinder, a cuboid, etc. The shape of the housing 211 may be determined according to the specific shape of the electrode assembly 22. For example, in FIG3 , the electrode assembly 22 is cylindrical, and accordingly, may 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 being mounted on the end cap 212 and the negative electrode terminal being mounted on the end of the housing 211 opposite the end cap 212. Of course, in other embodiments, the positive electrode terminal may be mounted on the end of the housing 211 opposite the end cap 212, and the negative electrode terminal may be mounted on the end cap 212.

[0266] Among them, 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. Exemplarily, the materials of the positive electrode terminal and the negative electrode terminal can be various, 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 electrode tab 2212 of the electrode assembly 22, for example, by welding or abutting, etc. The positive electrode terminal and the negative electrode terminal can also be indirectly connected to the electrode tab 2212 of the electrode assembly 22, for example, the positive electrode terminal and the negative electrode terminal are abutted or welded to the electrode assembly 22 through other components.

[0268] According to some embodiments of the present application, as shown in FIG. 3 , the battery cell 20 may further include a current collecting member 23 , which is disposed between the housing 21 and the tab 2212 along the first direction X. The current collecting member 23 connects the housing 21 and the tab 2212 .

[0269] Among them, the current collecting component 23 plays the role of connecting the tab 2212 of the electrode assembly 22 with the positive electrode terminal or the negative electrode terminal to achieve electrical connection between the electrode assembly 22 and the positive electrode terminal or the negative electrode terminal. The material of the current collecting component 23 can be various, such as copper, iron, aluminum, steel or aluminum alloy.

[0270] For example, in FIG3 , the battery cell 20 includes two current collecting members 23 , which are respectively arranged at both ends of the electrode assembly 22 in the first direction X. One current collecting member 23 connects the positive electrode terminal and one tab 2212 of the electrode assembly 22 , and the other current collecting member 23 connects 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 current collecting member 23 and the tab 2212 may be connected in various ways, such as welding, bonding or abutting. For example, in the embodiment of the present application, the current collecting member 23 and the tab 2212 are connected by welding.

[0272] By arranging a current collecting component 23 in the outer shell 21 of the battery cell 20, the outer shell 21 and the pole ear 2212 of the electrode assembly 22 are connected through the current collecting component 23, so that the input or output of electrical energy of the battery cell 20 can be realized. This structure is simple, easy to implement, and helps to reduce the difficulty of assembly between the pole ear 2212 and the outer shell 21.

[0273] According to some embodiments of the present application, referring to FIG3 and further referring to FIG18, FIG18 is a schematic diagram illustrating the connection between the current collecting member 23 and the tab 2212 of the electrode assembly 22 according to some embodiments of the present application. The current collecting member 23 is welded to the tab 2212. Along the first direction X, the thickness of the tab 2212 is D5, and the thickness of the current collecting member 23 is D6, satisfying D6 ≤ 1.5D5.

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

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

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

[0277] D6≤1.5D5, that is, the thickness of the current collecting member 23 is less than or equal to 1.5 times the thickness of the tab 2212. For example, the thickness D6 of the current collecting member 23 may be 1.5 times, 1.4 times, 1.2 times, 1.25 times, 1 times, 0.9 times, 0.8 times, 0.75 times, or 0.5 times the thickness D5 of the tab 2212.

[0278] During the experiment, the thickness of the current collecting member 23 and the thickness of the tab 2212 were set to different sizes. The experiments were conducted to make the ratio of the thickness of the current collecting member 23 to the thickness of the tab 2212 different. The experiments were conducted to measure the effect of the ratio of the thickness of the current collecting member 23 to the thickness of the tab 2212 on the welding assembly process of the current collecting member 23 and the tab 2212 under different conditions. The experimental results are as follows:

[0279] It can be seen from the above experimental data that when the ratio of the thickness of the current collecting component 23 to the thickness of the pole tab 2212 is greater than 1.5, the pole tab 2212 may be welded through, resulting in poor assembly quality of the current collecting component 23 and the pole tab 2212, which cannot meet the assembly requirements. When the ratio of the thickness of the current collecting component 23 to the thickness of the pole tab 2212 is less than or equal to 1.5, the phenomenon of the pole tab 2212 being welded through can be alleviated, which is beneficial to improving the assembly quality of the current collecting component 23 and the pole tab 2212. Therefore, the ratio of the thickness of the current collecting component 23 to the thickness of the pole tab 2212 is set to be less than or equal to 1.5, that is, D6≤1.5D5.

[0280] By setting the thickness of the current collecting component 23 in the first direction X to be less than or equal to 1.5 times the thickness of the pole tab 2212 in the first direction X, the phenomenon of excessive welding power required for welding the current collecting component 23 and the pole tab 2212 due to the thickness of the current collecting component 23 being too large than the thickness of the pole tab 2212 can be alleviated, thereby effectively reducing the risk of the pole tab 2212 being welded through, thereby reducing the phenomenon of damage to the electrode assembly 22, and helping to improve the production quality of the battery cell 20.

[0281] In some embodiments, as shown in FIG. 18 , the current collecting member 23 is welded to the electrode tab 2212 to form a weld mark 24 . Along the first direction X, the weld mark 24 covers the protrusion 22121 a of at least one electrode tab portion 22121 .

[0282] In the first direction X, the weld mark 24 covers the protrusion 22121a of at least one pole ear portion 22121 , that is, in the first direction X, the position where the current collecting member 23 and the pole ear 2212 are welded to each other is corresponding to the protrusion 22121a of at least one pole ear portion 22121 .

[0283] By setting the weld mark 24 formed by welding the current collecting component 23 and the pole tab 2212 to each other to cover the protrusion 22121a of at least one pole tab portion 22121 in the first direction X, the position where the current collecting component 23 and the pole tab 2212 are welded to each other is located in the area of ​​the pole tab 2212 thickened by the protrusion 22121a, which helps to further reduce the risk of the pole tab 2212 being welded through during the assembly process.

[0284] According to some embodiments of the present application, a battery 100 is further provided. The battery 100 includes a battery cell 20 according to any of the above solutions.

[0285] The battery 100 may further include a box body 10 , in which the battery cells 20 are accommodated.

[0286] Optionally, the battery cell 20 housed in the housing 10 may be one or more. For example, in FIG2 , the battery 100 includes multiple battery cells 20, and the multiple battery cells 20 are housed in the housing 10. The multiple battery cells 20 may be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a configuration in which the multiple battery cells 20 are connected in both series and parallel. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid configuration, and then the entire structure formed by the multiple battery cells 20 is housed in the housing 10.

[0287] According to some embodiments of the present application, an electric device is further provided. The electric device includes the battery 100 of any of the above solutions, and the battery 100 is used to provide electric energy to the electric device.

[0288] The power-consuming device may be any of the aforementioned devices or systems using the battery 100 .

[0289] According to some embodiments of the present application, referring to Figures 4 to 10 , the present application provides an electrode assembly 22 , which has a wound structure and includes two pole pieces 221 with opposite polarities and a separator 222 for isolating the two pole pieces 221 . The two pole pieces 221 and the separator 222 are wound along a winding direction Y to form a main body 223 and two pole tabs 2212 , and the pole tabs 2212 of the two pole pieces 221 are respectively arranged at both ends of the main body 223 in a first direction X. The pole piece 221 includes a main body 2211 and pole tabs 2212 , and the extension direction of the main body 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 region 22111a and a spacer region 22111b. The coating region 22111a and the spacer region 22111b are arranged along a first direction X. The active material layer 22112 is disposed in the coating region 22111a. The tab 2212 includes a plurality of tab portions 22121. The tab portions 22121 are connected to one end of the spacer region 22111b in the first direction X that is away from the coating region 22111a. The tab portions 22121 are spaced apart along the winding direction Y. At least a portion of the plurality of tab portions 22121 are stacked in the first direction X to form the tab 2212 at one end of the electrode assembly 22 in the first direction X. The tab 2212 has a thickness D5 in the first direction X, satisfying the condition 0.2 mm ≤ D5 ≤ 2.5 mm. Along the thickness direction Z of the pole ear portion, a plurality of protrusions 22121a are formed on one side of the pole ear portion 22121, and a groove 22121b is formed on the side of the pole ear portion 22121 away from the protrusion 22121a and corresponding to the position of the protrusion 22121a. Along the first direction X, in two adjacent pole ear portions 22121, the protrusion 22121a of one pole ear portion 22121 and the groove 22121b of the other pole ear portion 22121 are staggered. Along the thickness direction Z of the pole ear portion, the projection area of ​​the pole ear portion 22121 is S1, and the sum of the projection areas of the multiple protrusions 22121a on the pole ear portion 22121 is S2, satisfying that S2 / S1≥0.5, the pole ear portion 22121 includes a main body area 22121c that does not overlap with the projection of the protrusion 22121a in the thickness direction Z of the pole ear portion, and along the thickness direction Z of the pole ear portion, the maximum dimension of the pole ear portion 22121 is D1, and the thickness of the main body area 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, and the diameter of the protrusion 22121a in the direction perpendicular to the thickness direction Z of the pole ear is W1, satisfying 0.3mm≤W1≤2mm.

[0290] According to some embodiments of the present application, as shown in Figures 3 and 18, the present application provides a battery cell 20, which includes a housing 21, an electrode assembly 22, and a current collecting member 23. The electrode assembly 22 is housed within the housing 21. Along a first direction X, the current collecting member 23 is disposed between the housing 21 and the electrode tab 2212, connecting the housing 21 and the electrode tab 2212. The current collecting member 23 is welded to the electrode tab 2212 to form a weld mark 24. Along the first direction X, the weld mark 24 covers the protrusion 22121a of at least one electrode tab portion 22121. In the first direction X, the thickness of the electrode tab 2212 is D5, and the thickness of the current collecting member 23 is D6, satisfying the condition D6 ≤ 1.5D5.

[0291] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0292] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. An electrode assembly, include: Two pole pieces with opposite polarities and a separator for isolating the two pole pieces, wherein the two pole pieces and the separator are wound along a winding direction to form a main body and two pole ears; Among them, the pole ear and the main body are arranged along the first direction, the pole ear includes a plurality of pole ear portions arranged at intervals along the winding direction, the pole ear portion is bent relative to the first direction, at least a portion of the plurality of pole ear portions are stacked along the first direction, and a protrusion is formed on at least one side of the pole ear portion in its thickness direction.

2. The electrode assembly according to claim 1, in, A plurality of protrusions are formed on at least one side of the pole lug portion along a thickness direction of the pole lug portion.

3. The electrode assembly according to claim 2, in, Along the thickness direction of the pole ear portion, the projection area of ​​the pole ear portion is S 1 The sum of the projected areas of the plurality of protrusions on the pole ear is S 2 , meet, S 2 / S 1 ≥0.

5.

4. The electrode assembly according to any one of claims 1 to 3, in, The pole ear portion includes a main body region that does not overlap with a projection of the protrusion in a thickness direction of the pole ear portion, and the protrusion protrudes from the main body region along the thickness direction of the pole ear portion; Along the thickness direction of the pole ear portion, the maximum dimension of the pole ear portion is D 1 , the thickness of the main region is D 2 , satisfying, 2≤D 1 / D 2 ≤8.

5. The electrode assembly according to any one of claims 1 to 4, in, The pole ear portion is formed with a plurality of rows of protrusions, and each row of protrusions includes a plurality of protrusions arranged at intervals.

6. The electrode assembly according to claim 5, in, The maximum dimension of the protrusion in a direction perpendicular to the thickness direction of the pole ear portion is W. 1 , meet, 0.3mm≤W 1 ≤2mm.

7. The electrode assembly according to any one of claims 1 to 4, in, The pole ear portion is formed with a plurality of protrusions arranged at intervals, and two ends of the protrusions extend to two ends of the pole ear portion respectively along a direction perpendicular to an arrangement direction of the plurality of protrusions.

8. The electrode assembly according to claim 7, in, Along the arrangement direction of the plurality of protrusions, the width of the protrusion is W 2 , meet, 0.3mm≤W 2 ≤2mm.

9. The electrode assembly according to any one of claims 1 to 8, in, Along the thickness direction of the pole ear portion, the pole ear portion includes a plurality of foil materials stacked and arranged, a convex portion is formed on one side of the foil material, and a concave portion is formed at a position corresponding to the convex portion on the other side, and in two adjacent foil materials, the convex portion of one foil material is accommodated in the concave portion of the other foil material; Wherein, along the thickness direction of the pole ear portion, the convex portion located on one side of the pole ear portion is the protrusion.

10. The electrode assembly according to claim 9, in, A plurality of the foils are connected by welding to form the convex portion and the concave portion on the foils.

11. The electrode assembly according to claim 9 or 10, in, The pole piece includes a main body, a plurality of pole lugs are connected to the main body, the main bodies of two pole pieces and the separator are wound along the winding direction to form the main body, and the main body 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 which are stacked, wherein the first foil is connected to one end of the substrate in the first direction and is integrally formed with the substrate, and the second foil is separately arranged from the substrate.

12. The electrode assembly according to claim 11, in, The substrate includes a coating area and a spacing area, the coating area and the spacing area are arranged along the first direction, the active material layer is disposed in the coating area, and the spacing area connects the coating area and the first foil material.

13. The electrode assembly according to claim 11 or 12, in, Along the thickness direction of the pole ear portion, the thickness of the first foil is D 3 , the thickness of the second foil is D 4 , satisfying, 0.5≤D 3 / D 4 ≤2.

14. The electrode assembly according to any one of claims 11 to 13, in, Along a direction perpendicular to the thickness direction of the electrode ear portion, an end of the second foil material close to the substrate does not exceed an end of the first foil material connected to the substrate.

15. The electrode assembly according to any one of claims 11 to 14, in, Along a direction perpendicular to the thickness direction of the pole ear portion, a distance L between an end of the first foil material away from the substrate and an end of the second foil material away from the substrate satisfies that L≤2 mm.

16. The electrode assembly according to any one of claims 11 to 15, in, The first foil material and the second foil material are made of the same material.

17. The electrode assembly according to any one of claims 1 to 16, in, The pole piece comprises a main body, a plurality of pole ears are connected to one end of the main body in the first direction, and the main bodies and the isolation members of two pole pieces are wound along the winding direction to form the main body; Among them, the main body includes a substrate and an active material layer arranged 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 arranged in the coating area, and the spacer area connects the coating area and the pole ear part.

18. The electrode assembly according to claim 17, in, The pole ear portion and the spacer area are integrally formed.

19. The electrode assembly according to any one of claims 1 to 18, in, Along the thickness direction of the pole ear portion, a groove is formed on a side of the pole ear portion away from the protrusion and corresponding to the position of the protrusion.

20. The electrode assembly according to claim 19, in, Along the first direction, in two adjacent pole lug portions, the protrusion of one pole lug portion and the groove of the other pole lug portion are arranged in a staggered manner.

21. The electrode assembly according to any one of claims 1 to 20, in, Along the first direction, the thickness of the tab is D 5 , meet, 0.2mm≤D 5 ≤2.5mm.

22. The electrode assembly according to any one of claims 1 to 21, in, Along the first direction, the two tabs are respectively arranged at two ends of the main body.

23. The electrode assembly according to any one of claims 1 to 22, in, The main body is cylindrical.

24. A battery cell, include: shell; as well as The electrode assembly according to any one of claims 1 to 23, wherein the electrode assembly is accommodated in the housing.

25. The battery cell according to claim 24, in, The battery cell further comprises: A current collecting component is disposed between the housing and the electrode tab along the first direction, and the current collecting component connects the housing and the electrode tab.

26. The battery cell according to claim 25, in, The current collecting member is welded to the tab, and along the first direction, the thickness of the tab is D 5 , the thickness of the current collecting member is D 6 , satisfy,D 6 ≤1.5D 5 .

27. The battery cell according to claim 25 or 26, in, The current collecting member is connected to the electrode tab by welding to form a weld mark, and along the first direction, the weld mark covers the protrusion of at least one of the electrode tabs.

28. A battery comprising the battery cell according to any one of claims 24 to 27.

29. An electrical device comprising the battery as claimed in claim 28.

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