Battery cell, battery, and electric device

Abstract

This application discloses a battery cell, a battery, and an electrical device. The battery cell includes a casing and an adapter and an electrode assembly disposed within the casing. The electrode assembly includes a main body and a tab assembly. The main body is a cylindrical structure formed by winding electrode sheets. At least two loops of the electrode sheets extend from the end face of the main body, and multiple tabs arranged radially along the main body form a tab assembly. The tab assembly is bent towards the end of the main body, and the bent tabs in the tab assembly form a welding section and a connecting section. The connecting section connects the main body and the welding section and is curved. The welding sections of the multiple tabs in the tab assembly are stacked axially along the main body to form a welding portion, and the connecting sections of the multiple tabs in the tab assembly are stacked radially along the main body to form a connecting portion. The welding portion can form a dense welding structure and weld with the adapter, which can improve the welding quality between the tabs and the adapter.

Description

[0001] This application claims priority to Chinese Patent Application No. 202310791898.8, filed on June 30, 2023, with the Chinese Patent Office, entitled “Battery Cell and Method for Manufacturing Thereof, Battery and Electrical Device”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery manufacturing technology, and in particular to a battery cell, a battery, and an electrical device. Background Technology

[0003] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. In this context, electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the automotive industry's sustainable development. For electric vehicles, battery technology is a crucial factor in their development. Specifically, the tabs leading from the electrode components within the battery cell are typically welded to adapters; however, poor welding between the tabs and adapters is prone to occur, affecting the performance of the battery cell.

[0004] The above statements are for the purpose of providing background information in relation to this application only and do not necessarily constitute prior art. Utility Model Content

[0005] The purpose of this application is to provide a battery cell, a battery, and an electrical device that can reduce the risk of poor welding between the tabs and the adapter, thereby improving the performance of the battery cell.

[0006] The technical solution adopted in the embodiments of this application is: In a first aspect, a battery cell is provided, comprising a housing, an adapter, and an electrode assembly. The housing has a mounting cavity; the electrode assembly is located in the mounting cavity and includes a main body and a tab assembly. The main body is a cylindrical structure formed by winding electrode sheets. At least two loops of the electrode sheets extend from the end face of the main body, and multiple tabs arranged radially along the main body form a tab assembly. The tab assembly is bent toward the end of the main body, and the bent tabs in the tab assembly form a welding section and a connecting section. The connecting section connects the main body and the welding section and is curved. The welding sections of the multiple tabs in the tab assembly are stacked along the axial direction of the main body to form a welding portion, and the connecting sections of the multiple tabs in the tab assembly are stacked along the radial direction of the main body to form a connecting portion. The adapter and the welding portion are stacked along the axial direction of the main body, and the adapter is welded to the welding portion.

[0007] In this embodiment of the battery cell, after the electrode assembly is wound, the end of the main body of the electrode assembly is bent with tabs. The bent tabs in the tab assembly form welding sections and connecting sections. After the tab assembly is bent, the welding sections of multiple tabs in the tab assembly are stacked along the axial direction of the main body to form a welding part. The connecting sections of multiple tabs in the tab assembly are stacked along the radial direction of the main body. Then, the adapter is welded to the welding part, thus completing the welding of the tabs and the adapter. In this process, after the tabs are bent, the welding sections of multiple tabs in the tab assembly can be stacked flatly to form a tight welding part, thereby reducing the problem of poor welding between the welding part and the adapter, which is beneficial to improving the performance of the battery cell.

[0008] In one embodiment, the length of the connecting segment is L1, and the radius of the circle in the electrode corresponding to the connecting segment is R, where... .

[0009] By adopting the technical solution of this embodiment, the curvature of the tabs corresponding to the circles of different radii in the electrode sheet can be controlled to not be too large, thereby facilitating the folding and bending of the tabs. In addition, the pulling force generated on the main body by the folding and bending of the tabs is small, which reduces the risk of tab cracking and active material shedding, and is conducive to improving the yield and performance of battery cells.

[0010] In one embodiment, .

[0011] By adopting the technical solution of this embodiment, the curvature of the tabs corresponding to the different radii of the electrode sheets is smaller, making the closing and bending of the tabs simpler and less labor-intensive. Moreover, the pulling force generated by the closing and bending of the tabs on the main body is smaller, which can effectively reduce the risk of cracking of the connection and shedding of active material, and effectively improve the yield and performance of the battery cell.

[0012] In one embodiment, the length L1 of the connecting segment in at least one tab is less than the length of the welding segment.

[0013] By adopting the technical solution of this embodiment, the connecting section is shorter than the welding section, and the closing and bending of the electrode tab is simpler and faster, which is beneficial to the closing and bending of the electrode tab.

[0014] In one embodiment, the tab assembly has a pre-welded structure for connecting multiple tabs in the tab assembly.

[0015] By adopting the technical solution of this embodiment, multiple tabs in the tab assembly are pre-welded together to form a whole before bending, thereby reducing the risk of the tab assembly falling apart. In addition, after the tab assembly is bent, the multiple tabs in the tab assembly will fit together more tightly to form a more solid weld, which is beneficial to improving the welding quality of the tabs and the adapter, and is beneficial to improving the performance of the battery cell.

[0016] In one embodiment, the pre-welded structure is located at the welded section.

[0017] By adopting the technical solution of this embodiment, the pre-welded structure can weld multiple welding segments in the tab assembly together. This makes it less likely for the welded parts to fall apart after the tab assembly is bent, and a tight welded part can be formed after the tab is bent, resulting in better welding quality between the tab and the adapter and better performance of the battery cell. In addition, the pre-welded structure does not restrict the connecting segments, so the connecting segments can move relative to each other when the tab assembly is bent, which facilitates the bending of the tab.

[0018] In one embodiment, the distance between the pre-welded structure and the connecting part is L2, wherein... .

[0019] By adopting the technical solution of this embodiment, the distance between the pre-welded structure and the connecting part is reasonable, which is conducive to the bending of the tab assembly. At the same time, it can also enable the pre-welded structure to stably weld multiple welding segments in the tab assembly together, making the welding part less likely to fall apart and forming a tight welding part. This results in better welding quality between the tab and the adapter, and better performance of the battery cell.

[0020] In one embodiment, .

[0021] By adopting the technical solution of this embodiment, the distance design between the pre-welded structure and the connecting section is more reasonable, the risk of bending and pulling the electrode tab at the connection between the electrode tab and the main body is reduced, and the electrode tab assembly can be bent more smoothly.

[0022] In one embodiment, the pre-welded structure is located at the end of the welded section opposite to the connecting section.

[0023] With the technical solution of this embodiment, before bending the tab assembly, the ends of the welding sections away from the connecting section in the tab assembly are welded together, making the welding operation simple, convenient and quick; in addition, when the tab is bent, the part of the welding section near the connecting section can also move with the bending, making the bending operation of the tab assembly more time-saving and labor-saving.

[0024] In one embodiment, the length of the welded portion is L3, and the length of the pre-welded structure along the length direction of the welded portion is L4, wherein... .

[0025] By adopting the technical solution of this embodiment, the ratio between the length L4 of the pre-welded structure and the length L3 of the welded part is within the above range, which enables the pre-welded structure to reliably weld multiple welded segments in the tab assembly together, reducing the risk that the welded part is easy to loosen due to the length L4 of the pre-welded structure being too short, and also reducing the risk of the tab being welded out due to the length L4 of the pre-welded structure being too long.

[0026] In one embodiment, the total number of turns of the electrode is N1, and the total number of turns of the electrode connected to the tab is N2, wherein... .

[0027] By adopting the technical solution of this embodiment, the ratio of the total number of turns of the tabs to the total number of turns of the electrode sheet is within the above-mentioned range, which allows the electrode assembly to produce more tabs, thereby reducing the internal resistance of the electrode assembly during charging and discharging. If the number of tabs produced by the electrode assembly is small, the internal resistance of the electrode assembly during charging is large, which is not conducive to the rapid charging and discharging of the battery cell; if the number of tabs in the tab group produced by the electrode assembly is too large, the tab group is not easy to bend.

[0028] In one embodiment, .

[0029] By adopting the technical solution of this embodiment, the ratio of the total number of turns of the tabs to the total number of turns of the electrode sheet is more reasonable, and the number of tabs is reasonable, which is beneficial to the rapid charging and discharging of individual battery cells and also to the bending of the tab assembly.

[0030] In one embodiment, the electrode plates are spaced out from the end face of the main body to form a plurality of electrode groups, and the connecting portions of the plurality of electrode groups are arranged radially spaced along the main body.

[0031] By adopting the technical solution of this embodiment, the number of tabs led out from the electrode assembly can be reduced, making it easier to bend the tabs; there are multiple tab groups, and the number of tabs in a single tab group is small, making the bending of the tab group simpler and more convenient. By adopting the method of bending the tab groups in groups, the bending operation of the tab groups is also more time-saving and labor-saving.

[0032] In one embodiment, the number of tabs in the tab group near the inner ring of the electrode is N3, and the number of tabs in the tab group near the outer ring of the electrode is N4, wherein N3 > N4.

[0033] By adopting the technical solution of this embodiment, the tab assembly is easy to bend; in addition, the current-passing area of ​​the tab assembly near the outer ring of the electrode is not much different from that of the tab assembly near the inner ring of the electrode, which is conducive to better charging and discharging of the battery cell; and, when the current-passing area of ​​the tab assembly near the outer ring of the electrode is the same as that of the tab assembly near the inner ring of the electrode, the tabs in the tab assembly near the inner ring will not be designed to be too wide, thus preventing them from being unable to bend.

[0034] In one embodiment, the number of electrodes in the plurality of electrode groups gradually decreases along a first direction, which is the direction from the inner circle of the electrode to the outer circle of the electrode.

[0035] By adopting the technical solution of this embodiment, the number of electrodes in the electrode group with a smaller electrode width is greater, and the number of electrodes in the electrode group with a larger electrode width is smaller, making the electrode group easier to bend; in addition, the number of electrodes led out from the electrode assembly is also greater, which is conducive to the battery cell achieving faster charging and discharging.

[0036] In one embodiment, the distance between the connecting portions of two adjacent tab groups near the inner ring of the electrode is L5, and the distance between the connecting portions of two adjacent tab groups near the outer ring of the electrode is L6, wherein L6 > L5.

[0037] By adopting the technical solution of this embodiment, there are more tabs near the inner ring of the electrode and fewer tabs near the outer ring of the electrode. The tabs near the inner ring of the electrode are narrower and the tabs near the outer ring of the electrode are wider. This makes the current-carrying area of ​​the electrode assembly near the outer ring of the electrode and near the inner ring of the electrode not much different, which is beneficial for better charging and discharging of the battery cell. Furthermore, when the current-carrying area of ​​the electrode assembly near the outer ring of the electrode and near the inner ring of the electrode are the same, the tabs in the tab assembly near the inner ring will not be designed to be too wide, thus preventing them from being unable to bend.

[0038] In one embodiment, the spacing between the connecting portions of two adjacent electrode groups gradually increases along a first direction, which is the direction from the inner circle of the electrode to the outer circle of the electrode.

[0039] By adopting the technical solution of this embodiment, the number of tabs closer to the inner ring of the electrode increases, while the number of tabs closer to the outer ring of the electrode decreases. This makes the difference between the current flow area near the inner ring of the electrode and the current flow area near the outer ring of the electrode smaller, which is beneficial to improving the performance of the battery cell.

[0040] In one embodiment, the electrode assembly includes a plurality of tab groups, which are arranged circumferentially along the body portion.

[0041] By adopting the technical solution of this embodiment, the electrode groups are distributed in a dispersed manner, and the number of electrodes in a single electrode group can be reduced to facilitate the bending of the electrode group.

[0042] In one embodiment, at least one of the welding section and the connecting section has a hollow structure.

[0043] By adopting the technical solution of this embodiment, the hollow structure design can reduce the structural strength of the electrode tab, thereby facilitating the bending of the electrode tab.

[0044] In one embodiment, when the welding section has a hollow structure, the welding section includes multiple welding sections connected to the connecting section, the multiple welding sections are arranged at intervals along the length direction of the connecting section, and the gap between two adjacent welding sections forms a hollow structure; when the connecting section has a hollow structure, the connecting section includes multiple connecting sections connected to the welding section, the multiple connecting sections are arranged at intervals along the circumference of the main body, and the gap between two connected sections forms a hollow structure.

[0045] By adopting the technical solution of this embodiment, the position of the hollow structure can be flexibly set to meet different usage requirements.

[0046] In one embodiment, when both the welding section and the connecting section have hollow structures, multiple welding sections and multiple connecting sections are connected in a one-to-one correspondence.

[0047] By adopting the technical solution of this embodiment, the electrode tab is divided into a multi-segment break structure, making the electrode tab easy to bend and the electrode tab bending process more time-saving and labor-saving.

[0048] In one embodiment, the end of the welded portion facing away from the connecting portion is located on the side of the connecting portion facing the inner ring of the tab; or, the end of the welded portion facing away from the connecting portion is located on the side of the connecting portion facing away from the inner ring of the tab.

[0049] By adopting the technical solution of this embodiment, the bending direction of the electrode tab can be flexibly set to meet different usage requirements.

[0050] In one embodiment, the welded portion is located between the main body and the adapter.

[0051] By adopting the technical solution of this embodiment, after the electrode tab is bent, the adapter can be placed on the welding part for welding, and the assembly operation is simple.

[0052] In one embodiment, the battery cell further includes a connector, and the connector is welded between the welding portion and the adapter; and / or, the welding portion is welded between the connector and the adapter.

[0053] By adopting the technical solution of this embodiment, the connection can increase the welding thickness, reduce the risk of damage to the main body due to weld penetration, and improve the welding quality of the welded parts and the adapter.

[0054] In one embodiment, the thickness of the welded portion is H1, the thickness of the connector is H2, the number of connectors is N, and the thickness of the welding position between the adapter and the welded portion is H3, wherein... .

[0055] By adopting the technical solution of this embodiment, through The design ensures that the sum of the thickness of the welded part and all the connecting parts is greater than or equal to the thickness H3 of the weld position between the adapter and the welded part. This makes the sum of the thickness of the welded part and all the connecting parts larger than the thickness of the weld position of the welded part, making it less likely for the welded part and connecting parts to be welded through. This reduces damage to the main body, improves welding quality, and increases the yield rate of battery cells.

[0056] In one embodiment, when a connector is welded between the welded part and the adapter, the thickness H1 of the welded part is greater than the thickness H2 of the connector.

[0057] By adopting the technical solution of this embodiment, when welding the welding part and the adapter, since the connector is located between the welding part and the adapter, the welding part is welded from the weld bead of the connector. Since the thickness H1 of the welding part is greater than the thickness H2 of the connector, the welding part is not easily welded through, reducing the risk of damage to the main body and improving the welding quality and the yield of the battery cell.

[0058] In one embodiment, the thickness of the connector is H2, wherein 0.2mm ≤ H2 ≤ 0.4mm.

[0059] By adopting the technical solution of this embodiment, the thickness H2 of the connector is set within the range of 0.2mm to 0.4mm. The thickness H2 of the connector is set reasonably. On the one hand, it can reduce the risk of damage to the main body caused by the welded part being burned through. On the other hand, the connector will not occupy too much space, which is conducive to improving the volumetric energy density of the battery cell. With this design, the thickness H2 of the connector will not be too small, which would easily cause the connector and the welded part to be burned through. The thickness H2 of the connector will not be too large, which would occupy too much space of the battery cell.

[0060] In one embodiment, the adapter is located between the welded portion and the main body.

[0061] By adopting the technical solution of this embodiment, the adapter is located between the welding part and the main body. In this way, during welding, the welding is done from the welding part to the adapter. The structural strength of the adapter is usually better than that of the welding part, making the adapter less likely to be welded through, thereby reducing the risk of damage to the main body and improving the welding quality and the yield of battery cells.

[0062] In one embodiment, the adapter is provided with a through hole, and the connecting part passes through the through hole.

[0063] By adopting the technical solution of this embodiment, after the tab assembly is bent through the through hole, the welding part is located on the side of the adapter facing away from the main body. The through hole provides space for the tab assembly to pass through, which is simple in structure and easy to process and manufacture.

[0064] In one embodiment, when the end of the welded portion facing away from the connecting portion is located on the side of the connecting portion near the inner ring of the electrode tab, the connecting portion is located on the side of the adapter near the outer ring of the electrode plate.

[0065] By adopting the technical solution of this embodiment, the tab assembly passes directly through the side of the adapter near the outer ring of the electrode plate and then bends, so that the welding part can be located on the side of the adapter facing away from the main body, without the need to set a through structure in the adapter, which is convenient for processing and manufacturing.

[0066] In one embodiment, the adapter has a notch on the side near the outer ring of the electrode, and the connecting part is located inside the notch.

[0067] By adopting the technical solution of this embodiment, the notch can provide installation space for the connecting part, making it less likely for the connecting part to protrude beyond the outer peripheral wall of the main body. A certain distance can be maintained between the connecting part and the cavity wall of the mounting cavity, reducing the risk of compression between the connecting part and the outer shell, which is conducive to improving the reliability of the battery cell. Moreover, the overall structure is compact, which is conducive to improving the energy density of the battery cell.

[0068] In one embodiment, the battery cell includes multiple tab groups, with the welding portion of a portion of the tab group located between the main body and the adapter; the welding portion of another portion of the tab group is located on the side of the adapter facing away from the main body.

[0069] By adopting the technical solution of this embodiment, the electrode assembly's tabs are divided into multiple tab groups, so that the number of tabs in each tab group can be designed to be smaller, making it easier to bend; in addition, the position of the welding part of the tab group can also be flexibly set, making assembly simpler and more convenient.

[0070] In one embodiment, the adapter includes a flip-up portion and a fixing portion connected together, the flip-up portion being welded to a welding portion, and the flip-up portion being able to flip relative to the fixing portion.

[0071] By adopting the design scheme of this embodiment, the welding direction of the welding laser can be changed, thereby reducing the risk that the welding laser will penetrate the welded part without damaging the main body, thus improving the performance of the battery cell. Secondly, a method for manufacturing a battery cell is provided, for manufacturing a battery cell as described in the above embodiment. The battery cell manufacturing method includes the following steps: The tabs of the electrode assembly are bent toward the end of the main body of the electrode assembly. The main body is a cylindrical structure formed by winding electrode sheets. At least two loops of the electrode sheets lead out of the end face of the main body. Multiple tabs arranged radially along the main body form a tab assembly. After the tabs in the tab assembly are bent, they form welding sections and connecting sections. The welding sections of the multiple tabs are stacked along the axial direction of the main body to form a welding part. The connecting sections of the multiple tabs are stacked along the radial direction of the main body to form a connecting part. The adapter is welded to the welding part, and the adapter and the welding part are stacked along the axial direction of the main body; The welded adapter and electrode assembly are then installed into the mounting cavity of the housing.

[0072] The battery cell manufacturing method of this application embodiment first bends the tab assembly to form a welding part and a connecting part, then welds the welding part together with the adapter, and finally installs the welded electrode assembly and adapter into the mounting cavity of the housing. In this process, the welding part formed after bending the tab assembly can be flat and tightly fitted together to form a tight welding part, thereby reducing the problem of poor welding between the welding part and the adapter, which is beneficial to improving the performance of the battery cell.

[0073] In one embodiment, the tab assembly is gathered along the stacking direction of the welded section before the tab assembly is bent.

[0074] By adopting the technical solution of this embodiment, the compression and gathering can make the bent welding section fit together more tightly to form a tighter weld, reducing the risk of welding defects such as incomplete welding and weld burn-through, and is more conducive to improving the welding quality of the adapter and the electrode tab.

[0075] In one embodiment, after the tabs are folded up and before they are bent, the tab assembly is pre-welded so that the tabs in the tab assembly are welded together.

[0076] By adopting the technical solution of this embodiment, after the electrode tabs are folded up and before the electrode tabs are bent, the electrode tabs in the electrode tab assembly are welded together by pre-welding. This can reduce the risk of the electrode tabs becoming loose after bending, and make the welded sections in the subsequent welded part fit together to form a tight welded part, thereby reducing the risk of poor welding such as incomplete welding and burn-through, and improving the welding quality of the welded part and the adapter.

[0077] In one embodiment, the pre-welded tab assembly is located at the end opposite to the main body.

[0078] By adopting the technical solution of this embodiment, pre-welding is performed on the end of the tab assembly facing away from the main body. After welding, the end of the tab assembly near the main body is in a free state, so as to facilitate the bending of the tab assembly.

[0079] Thirdly, a battery is provided, comprising a battery cell as described in the above embodiments, and / or comprising a method for obtaining a battery cell using a battery cell manufacturing method as described in the above embodiments.

[0080] Thirdly, an electrical device is provided, including a battery as described in the above embodiments.

[0081] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0082] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only one embodiment of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0083] Figure 1 This is a schematic diagram of the structure of a vehicle provided in one embodiment of this application.

[0084] Figure 2 This is a schematic diagram of the structure of a battery provided in one embodiment of this application.

[0085] Figure 3 This is a cross-sectional view of a battery cell provided in an embodiment of this application.

[0086] Figure 4 This is an exploded view of a battery cell provided in an embodiment of this application.

[0087] Figure 5 for Figure 4 The diagram shows the structure of a single battery cell.

[0088] Figure 6 For along Figure 5 Cross-sectional view of line AA in the middle.

[0089] Figure 7 for Figure 6 A magnified view of a section at point B in the middle.

[0090] Figure 8 for Figure 7 A magnified view of a section at point C.

[0091] Figure 9 A simplified flowchart of the battery cell manufacturing process provided in an embodiment of this application.

[0092] Figure 10 for Figure 9 A magnified view of a section at point D.

[0093] Figure 11 This is a schematic diagram of the electrode assembly of a battery cell provided in another embodiment of this application, from one perspective.

[0094] Figure 12 for Figure 11 A schematic diagram of the electrode assembly from another perspective.

[0095] Figure 13 This is a schematic diagram of the electrode assembly of a battery cell provided in another embodiment of this application, from one perspective.

[0096] Figure 14 for Figure 13 A schematic diagram of the electrode assembly from another perspective.

[0097] Figure 15 This is a schematic diagram of the structure of the electrode assembly of a battery cell provided in another embodiment of this application.

[0098] Figure 16 This is a partially enlarged view of the cross-section of a battery cell provided in another embodiment of this application.

[0099] Figure 17 A cross-sectional view of a battery cell provided in another embodiment of this application.

[0100] Figure 18 for Figure 17 A magnified view of a section at point E in the middle.

[0101] Figure 19 A cross-sectional view of a battery cell provided in another embodiment of this application.

[0102] Figure 20 for Figure 19 A magnified view of a section at point F.

[0103] Figure 21 for Figure 17 The diagram shows the structure of the end cap and adapter of the battery cell.

[0104] Figure 22 This is a partially enlarged view of the cross-section of a battery cell provided in another embodiment of this application.

[0105] Figure 23 This is a partially enlarged view of the cross-section of a battery cell provided in another embodiment of this application.

[0106] Figure 24 This is a partially enlarged view of the cross-section of a battery cell provided in another embodiment of this application.

[0107] Figure 25 This is a schematic diagram of the end cap and adapter of a battery cell provided in another embodiment of this application.

[0108] The following are the labeling elements in the figure: 1000, Vehicle; 1100, Battery; 1200, Controller; 1300, Motor; 10, Housing; 20, Battery Cell; 210, Casing; 211, Shell; 212, End Cap; 2121, Electrode Terminal; 2111, Mounting Cavity; 220, Electrode Assembly; 221, Main Body; 222, Electrode Lugs; 2221, Welding Part; 2222, Connecting Part; 2223, Spacing; 223, Electrode Sheet; 2231 2232. First electrode; 2233. Second electrode; 224. Electrode lug; 2241. Welding section; 2242. Welding zone; 2243. Connecting section; 2244. Connecting zone; 2245. Hollow structure; 225. Pre-welded structure; 226. Diaphragm; 230. Adapter; 231. Through hole; 232. Notch; 233. Flipping part; 234. Fixing part; 235. Connecting structure; 240. Connector; 250. Restraining layer. Detailed Implementation

[0109] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0110] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0111] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0112] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments in any suitable manner.

[0113] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0114] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces). "Several" means one or more, unless otherwise explicitly specified.

[0115] In the description of the embodiments of this application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0116] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0117] In the description of the embodiments of this application, unless otherwise expressly specified and limited, when an element is referred to as "fixed to" or "set on" another element, it may be directly on or indirectly on the other element. When an element is referred to as "connected to" another element, it may be directly connected to or indirectly connected to the other element.

[0118] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. In this context, electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the automotive industry's sustainable development. And for electric vehicles, battery technology is a crucial factor in their development.

[0119] A battery cell is the smallest unit that makes up a battery. The battery cell's casing houses an electrode assembly, which is a cylindrical structure formed by layering positive and negative electrode plates and a separator. The electrode assembly primarily relies on the movement of active ions (e.g., lithium ions) between the positive and negative electrode plates for charging and discharging. The positive electrode plate includes a positive current collector and multiple positive tabs extending from the edge of the current collector. The current collector and tabs can be obtained through die-cutting, or by welding a conductor to the edge of the current collector to form the tabs. The current collector is typically covered with a positive active material, while the tabs are not. Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode includes a negative current collector and multiple negative tabs extending from the edge of the current collector. The current collector and tabs can be obtained through die-cutting, or by welding a conductor to the edge of the current collector. The current collector is typically covered with a negative active material, while the tabs are not. The current collector can be made of copper, and the active material can be carbon or silicon, etc. The separator can be made of polypropylene (PP) or polyethylene (PE), etc. The separator is an insulating film placed between the positive and negative electrodes. Its main function is to isolate the positive and negative electrodes and prevent electrons from freely passing through, thus preventing short circuits, while allowing ions in the electrolyte to freely pass between the positive and negative electrodes to form a circuit.

[0120] During battery cell manufacturing, in some cases, the cells are arranged and stacked in the order of positive electrode sheet—separator—negative electrode sheet—separator, and then wound together. After winding, the positive current collector, negative current collector, and separator form the main body of the electrode assembly, i.e., the main body. Positive electrode tabs extend axially from the end of the main body, and multiple positive electrode tabs are stacked together radially to form a positive electrode tab group. Similarly, negative electrode tabs extend axially from the end of the main body, and multiple negative electrode tabs are stacked together radially to form a negative electrode tab group. The casing typically has electrode terminals and adapters. After welding the adapters to the positive and negative electrode tab groups, the adapter pieces are connected to the electrode terminals, thus enabling current input and output through the electrode terminals. It can be understood that the adapters include positive and negative adapters, and the electrode terminals include positive and negative electrode terminals. The positive adapter connects the positive electrode tab group and the positive electrode terminal, and the negative adapter connects the negative electrode terminal and the negative electrode tab group. For ease of description, positive and negative electrode plates can be collectively referred to as electrode plates, positive and negative electrode tabs can be collectively referred to as electrode tabs, positive and negative adapters can be collectively referred to as adapters, and positive and negative electrode terminals can be collectively referred to as electrode terminals.

[0121] During the manufacturing process of a battery cell, the wound tabs are usually arc-shaped. The arc-shaped tabs are flattened before being welded to the adapter. However, the flattened tabs are prone to wrinkling and accumulating, and the roots near the outer ring tabs tend to expand outward. Gaps or poor fit may occur between the tabs, meaning that the flattening and compaction of the tabs is insufficient. This can lead to poor welding problems such as incomplete soldering or burn-through when welding the adapter to the tabs, affecting the performance of the battery cell.

[0122] To improve the problem of poor welding between the adapter and the tabs, this application provides a battery cell. After the electrode sheets are wound, the tab assembly extending from the end of the main body is bent toward the end of the main body. After bending, the tabs in the tab assembly form welding sections and connecting sections. The welding sections of multiple tabs are stacked along the axial direction of the main body to form a welding part, and the connecting sections of multiple tabs are stacked along the radial direction of the main body to form a connecting part. The welding part is then stacked and welded together with the adapter, and finally installed into the mounting cavity of the casing, thus completing the manufacturing of the battery cell. In this process, after the tab assembly is bent, the welding sections of multiple tabs in the tab assembly can be stacked flatly together to form a tight welding part, thereby reducing the problem of poor welding between the welding part and the adapter, which is beneficial to improving the performance of the battery cell.

[0123] The battery cell, battery, and electrical device using the battery as a power source disclosed in this application can be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0124] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0125] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in one embodiment of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, or a range-extended electric vehicle, etc. A battery 1100 is disposed inside the vehicle 1000, and the battery 1100 can be located at the bottom, front, or rear of the vehicle 1000. The battery 1100 can be used to power the vehicle 1000; for example, the battery 1100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 1200 and a motor 1300. The controller 1200 is used to control the battery 1100 to supply power to the motor 1300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0126] In one embodiment of this application, the battery 1100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0127] Please refer to Figure 2 As one embodiment of the battery 1100, the battery 1100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 provides a space for the battery cell 20 and can adopt various structures. In one embodiment, the housing 10 may include a first part and a second part, which overlap each other, jointly defining a space for accommodating the battery cell 20. The second part may be a hollow structure with one open end, while the first part may be a plate-like structure, covering the open side of the second part so that the first and second parts jointly define the space. Alternatively, both the first and second parts may be hollow structures with one open side, with the open side of the first part covering the open side of the second part. Of course, the housing 10 formed by the first and second parts can be of various shapes, such as a cylinder, a cuboid, etc.

[0128] In battery 1100, there can be multiple battery cells 20. Multiple battery cells 20 can be connected in series, in parallel, or in a mixed manner. A mixed manner means that multiple battery cells 20 are connected in both series and parallel.

[0129] In one embodiment, multiple battery cells 20 can be directly connected in series, parallel, or in a hybrid configuration, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery 1100 can also be formed by first connecting multiple battery cells 20 in series, parallel, or in a hybrid configuration to create a battery module, and then connecting multiple battery modules in series, parallel, or in a hybrid configuration to form a whole, which is then housed within the housing 10. The battery 1100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.

[0130] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 20 can be cylindrical, flat, cuboid, or other shapes.

[0131] As another embodiment of the battery 1100, the battery 1100 may not include the housing 10, but instead connect multiple battery cells 20 electrically and assemble them into an electrical device after forming a whole through necessary fixing structures.

[0132] Please refer to Figure 3 and Figure 4 , Figure 3 This is a cross-sectional view of a battery cell 20 provided in an embodiment of this application. Figure 4 This is an exploded structural diagram of a battery cell 20 provided in an embodiment of this application. The battery cell 20 refers to the smallest unit that makes up a battery. Figure 3 As shown, the battery cell 20 includes a housing 210, an electrode assembly 220, a binding layer 250, and other functional components. The housing 210 is a component used to isolate the internal environment of the battery cell 20 from the external environment, and the housing 210 encloses a mounting cavity 2111, which provides mounting space for components such as the electrode assembly 220 and the binding layer 250; for example, such as... Figure 4 As shown, the outer casing 210 includes a housing 211 and an end cap 212.

[0133] End cap 212 refers to a component that covers the opening of housing 211 and together with housing 211 forms a mounting cavity 2111 to isolate the internal environment of battery cell 20 from the external environment. In any case, the shape of end cap 212 can be adapted to the shape of housing 211 to fit housing 211. In one embodiment, end cap 212 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that end cap 212 is not easily deformed under pressure and impact, enabling battery cell 20 to have higher structural strength and improved safety performance. End cap 212 can be provided with functional components such as electrode terminals 2121 and adapters 230. Adapters 230 are located within mounting cavity 2111 and are used to electrically connect electrode terminals 2121 and electrode assembly 220. Electrode terminals 2121 are exposed from the outside of end cap 212 and are used to electrically connect to external electrical equipment for outputting or inputting electrical energy from battery cell 20. In one embodiment, the end cap 212 may also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. The end cap 212 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this. In one embodiment, an insulating member may also be provided on the inner side of the end cap 212. The insulating member can be used to isolate the electrical connection components within the housing 211 from the end cap 212 to reduce the risk of short circuits. For example, the insulating member can be plastic, rubber, etc.

[0134] The housing 211 is a component used to cooperate with the end cap 212 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 220, electrolyte, and other components. The housing 211 and the end cap 212 can be independent components. An opening can be provided on the housing 211, and the end cap 212 can be used to close the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 212 and the housing 211 can be integrated. Specifically, the end cap 212 and the housing 211 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 211, the end cap 212 closes the housing 211. The housing 211 can have various shapes and sizes, such as cuboid, cylindrical, or hexagonal prism. Specifically, the shape of the housing 211 can be determined according to the specific shape and size of the electrode assembly 220. The shell 211 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This application embodiment does not impose any special restrictions on this.

[0135] Electrode assembly 220 is the component in the battery cell 20 where electrochemical reactions occur. The housing 211 may contain one or more electrode assemblies 220. Electrode assembly 220 includes a first electrode 2231, a second electrode 2232, and a separator 226. The first electrode 2231 and the second electrode 2232 have different polarities; that is, one of the first electrode 2231 and the second electrode 2232 is a positive electrode, and the other is a negative electrode. During the charging and discharging process of the battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator 226 is disposed between the positive and negative electrodes, which can prevent short circuits between the positive and negative electrodes while allowing active ions to pass through. The electrode assembly 220 is arranged and stacked in the order of positive electrode plate—separator 226—negative electrode plate—separator 226 and then wound to form a cylindrical electrochemical structure. After the electrode assembly 220 is wound, a binding layer 250 is applied to ensure that the positive electrode plate, negative electrode plate and separator 226 are tightly wound together. The binding layer 250 includes, but is not limited to, an insulating film, such as a blue film.

[0136] See Figures 4-12As shown, this application embodiment provides a battery cell 20, including a housing 210, an adapter 230, and an electrode assembly 220. The housing 210 has a mounting cavity 2111; the electrode assembly 220 is located in the mounting cavity 2111, and the electrode assembly 220 includes a main body 221 and a tab group 222. The main body 221 is a cylindrical structure formed by winding electrode sheets 223. At least two loops of electrode sheets 223 extend from the end face of the main body 221, and a plurality of tabs 224 arranged radially along the main body 221 form the tab group 222; the tab group 222 is bent toward the end of the main body 221. In section 2, the tab 224 is bent to form a welding section 2241 and a connecting section 2243. The connecting section 2243 is connected between the main body 221 and the welding section 2241, and the connecting section 2243 is bent. The welding sections 2241 of the multiple tabs 224 in the tab assembly 222 are stacked along the axial direction of the main body 221 to form a welding section 2221. The connecting sections 2243 of the multiple tabs 224 in the tab assembly 222 are stacked along the radial direction of the main body 221 to form a connecting section 2222. The adapter 230 and the welding section 2221 are stacked along the axial direction of the main body 221, and the adapter 230 is welded to the welding section 2221.

[0137] The main body 221 may refer to a cylindrical structure formed by winding the electrode 223; for example, the main body 221 may also be a part of a cylindrical structure formed by winding the positive current collector, the negative current collector and the separator 226, wherein the electrode 223 in the following embodiments may refer to a positive electrode or a negative electrode.

[0138] The tab 224 can refer to a conductive component extending from the end face of the main body 221; specifically, the tab 224 can also refer to a portion extending from the edge of the current collector of the electrode 223 that is not coated with active material; it is understood that this should be considered in conjunction with... Figure 3 , Figure 11 and Figure 12As shown, before the electrode 223 is wound, the electrode 223 and the diaphragm 226 are laid flat and stacked. The electrode 223 is provided with a plurality of tabs 224, which are distributed sequentially and at intervals along the length direction of the current collector. After the electrode 223 is wound one turn at a time, at least some turns of the electrode 223 have tabs 224 leading out, that is, at least two turns of the electrode 223 have tabs 224 leading out from the end of the main body 221. Furthermore, at least some of the tabs 224 of the same polarity gather at one place and are stacked along the radial direction of the main body 221 to form a tab group 222. That is, the tab group 222 refers to the combination formed by stacking a plurality of tabs 224 of the same polarity along the radial direction of the main body 221. In addition, as the electrode 223 is wound, the tabs 224 are also bent into a bent shape. The number of tab groups 222 can be multiple, and the specific number is set according to the connection structure with the adapter 230. The tab group 222 can be divided into a positive tab group 222 and a negative tab group 222. The tab 224 in the positive tab group 222 is the positive tab, and the tab 224 in the negative tab group 222 is the negative tab. The tab 224 led out from the positive electrode plate is the positive tab, and the tab 224 led out from the negative electrode plate is the negative tab.

[0139] Please refer to the following: Figure 9 and Figure 10 As shown, in the actual manufacturing process, before bending the tab assembly 222, the tab assembly 222 can be squeezed and gathered along the stacking direction (X direction) of the tab 224 and then bent toward the end face of the main body 221 to reduce the height of the electrode assembly 220 and facilitate the stacking and welding with the adapter 230.

[0140] After the tab 224 in the tab assembly 222 is bent, it forms a welding section 2241 and a connecting section 2243. The connecting section 2243 connects the main body 221 and the welding section 2241, and the connecting section 2243 is bent. It can be understood that after the tab 224 is bent, the bending of the tab 224 (see...) Figure 11 The dotted line in the diagram marks the boundary between two parts: the part closer to the main body 221 is the connecting section 2243, and the part farther from the main body 221 is the welding section 2241. For example, please refer to the diagram. Figure 13 As shown, where, Figure 13The dashed line on the tab assembly 222 indicates the bend of the tab assembly 222. The tab assembly 222 bends along the dashed line, which divides the tab assembly 222 into two parts. The part connected to the main body 221 is the connecting part 2222, and the part connected to the connecting part 2222 is the welding part 2221. The part of the tab 224 located in the welding part 2221 is the welding segment 2241, and the part of the tab 224 located in the connecting part 2222 is the connecting segment 2243. After the tab assembly 222 bends toward the end face of the main body 221, the connecting segments 2243 of the multiple tabs 224 in the tab assembly 222 are stacked radially along the main body 221, and the welding segments 2241 of the multiple tabs 224 in the tab assembly 222 are stacked axially along the main body 221. The radial direction of the main body 221 can be referred to as the X direction in the figure, the axial direction of the main body 221 can be referred to as the Z direction in the figure, the axis of the main body 221 can be referred to as line AA in the figure, and the circumferential direction of the main body 221 can be referred to as the direction indicated by the double-headed arrow M in the figure.

[0141] The connecting segment 2243 is curved, which is understandable given the combination... Figure 11 and Figure 12 As shown, after the electrode 223 is wound, the electrode tab 224 is led out along the axial direction of the main body 221 and is arc-shaped; after the electrode tab 224 is gathered and bent, the welding section 2241 may be squeezed into a flat shape or may maintain a certain curvature; while the connecting section 2243 may be straight in the near part, and the part near the main body 221 will always have a certain curvature, or may maintain a certain curvature overall; however, the connecting section 2243 will always present a certain curvature and bend due to the influence of the winding of the electrode 223.

[0142] Adapter 230 may refer to a component that is soldered to the tab 224 of electrode assembly 220. Adapter 230 is conductive for outputting or inputting electrical energy to electrode assembly 220. In one embodiment, combined with... Figure 7As shown, the adapter 230 can be mounted on the end cap 212. For example, the end cap 212 has electrode terminals 2121, and the adapter 230 is located inside the end cap 212. The adapter 230 is connected to the electrode terminals 2121 to output or input electrical energy from the battery cell 20 through the electrode terminals 2121. The adapter 230 can be integrally connected to the electrode terminals 2121 or separately connected to them. For example, the adapter 230 can be connected to the electrode terminals 2121 by welding, snap-fitting, threading, etc. In some embodiments, the adapter 230 can also be mounted on the housing 211. For example, the adapter 230 is mounted on the wall surface of the housing 211 and the end cap 212. The adapter 230 can be made of a conductive material with a certain hardness and strength, such as copper or aluminum. It should be noted that when the adapter 230 is connected to the electrode terminal 2121, the material of the adapter 230 and the electrode terminal 2121 can be the same or different. The welding part 2221 and the adapter 230 are stacked along the axial direction of the main body 221. During actual welding, the adapter 230 is welded to the welding part 2221 along the axial direction of the main body 221. In this way, the adapter 230 can be welded together with at least most of the welding segments 2241 within the welding part 2221, resulting in good welding strength between the welding part 2221 and the adapter 230, which is beneficial to improving the reliability of the electrical connection between the welding part 2221 and the adapter 230.

[0143] In this embodiment of the battery cell 20, after the electrode assembly 220 is wound, the end of the main body 221 of the electrode assembly 220 is bent with a tab group 222. The tabs 224 in the tab group 222 are bent to form a welding section 2241 and a connecting section 2243. After the tab group 222 is bent, the welding sections 2241 of the multiple tabs 224 in the tab group 222 are stacked along the axial direction of the main body to form a welding portion 2221, and the connecting portion 222 of the multiple tabs 224 in the tab group 222 is formed. The connecting segments 2243 are stacked radially along the main body. Then, the adapter 230 is welded onto the welding part 2221, thus completing the welding of the tab 224 and the adapter 230. During this process, after the tab 224 is bent, the welding segments 2241 of multiple tabs 224 in the tab group 222 can be stacked together flat to form a tight welding part 2221, thereby reducing the problem of poor welding between the welding part 2221 and the adapter 230, which is beneficial to improving the performance of the battery cell 20.

[0144] In another embodiment, combined Figure 11 and Figure 12 As shown, the length of the connecting segment 2243 is L1, and the radius of one loop connecting the electrode 223 and the connecting segment 2243 is R. .

[0145] The length of the connecting segment 2243 can refer to the arc length L1 of the connecting segment 2243 before the tab 224 is retracted and bent.

[0146] The loop in which the electrode 223 is connected to the connecting segment 2243 can refer to the loop in the electrode 223 that is connected to the connecting segment 2243. After the electrode 223 is wound, it forms loops that are close to a circle. In actual measurement, the loop in which the electrode 223 is connected to the connecting segment 2243 can refer to the loop in the electrode 223 that is wound around the axis of the main body 221 starting from one side of the connecting segment 2243 and moving towards the other side of the connecting segment 2243. The size of this loop in the radial direction of the main body 221 is defined as R.

[0147] By adopting the technical solution of this embodiment, the curvature of the tabs 224 corresponding to the circles of different radii in the electrode sheet 223 can be controlled to not be too large, thereby facilitating the folding and bending of the tabs 224. In addition, the pulling force generated on the main body 221 by the folding and bending of the tabs 224 is small, which reduces the risk of the tabs 224 cracking and active material falling off, which is conducive to improving the yield and performance of the battery cell 20.

[0148] In another embodiment of this application, combined with Figure 11 and Figure 12 As shown, .

[0149] By adopting the technical solution of this embodiment, the arc of the tabs 224 led out by the circles corresponding to different radii of the electrode 223 is smaller, making the folding and bending of the tabs 224 simpler and less labor-intensive. Moreover, the pulling force generated by the folding and bending of the tabs 224 on the main body 221 is smaller, which can effectively reduce the risk of the tabs 224 cracking and active material shedding, and effectively improve the yield and performance of the battery cell 20.

[0150] In one embodiment, The value can be, but is not limited to, 0.1, 0.4, 0.8, 1.2, 1.57, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, or 3.14.

[0151] In another embodiment of this application, combined with Figure 11 and Figure 12 As shown, the length L1 of the connecting segment 2243 in at least one tab 224 is less than the length L7 of the welding segment 2241.

[0152] The length L7 of the welding segment 2241 can refer to the arc length of the welding segment 2241 before the tab 224 is closed and bent. Here, the connecting segment 2243 and the welding segment 2241 are both located within the same tab, meaning the lengths of the connecting segment 2243 and the welding segment 2241 within the same tab are different, and the length of the connecting segment 2243 is less than the length of the welding segment 2241. Figure 11 and Figure 12 As shown, the tabs 224 have notches at both ends of the connecting section 2243, such that the length L1 of the connecting section 2243 is less than the length L7 of the welding section 2241. Here, "both ends of the connecting section 2243" refers to the two ends of the connecting section 2243 along the circumference of the main body 221. Furthermore, the number of tabs whose length of the connecting section 2243 is less than the length of the welding section 2241 can be one, two, three, or more; alternatively, all tabs 224 in the tab group 222 can have a structure where the length of the connecting section 2243 is less than the length of the welding section 2241.

[0153] By adopting the technical solution of this embodiment, the connecting section 2243 is shorter than the welding section 2241, and the closing and bending of the tab 224 is simpler and faster, which is beneficial to the closing and bending of the tab 224.

[0154] In another embodiment, combined Figure 9 and Figure 10 As shown, the tab assembly 222 is provided with a pre-welded structure 225, which is used to connect multiple tabs 224 in the tab assembly 222.

[0155] The pre-welded structure 225 can refer to a welded structure formed by welding multiple electrodes 224 in the electrode assembly 222 together before welding the welding part 2221 to the adapter 230. For example, the pre-welded structure 225 can refer to structures such as welds or weld marks that weld the multiple electrodes 224 together in the electrode assembly 222. Please refer to the following in conjunction with... Figure 25 As shown, the tab assembly 222 and the welding part 2221 are welded to form a connecting structure 235. The pre-welded structure 225 and the connecting structure 235 are staggered, so that the two welding of the tab assembly 222 are not in the same place, which is beneficial to improving the welding quality and the performance of the battery cell 20. The pre-welded structure 225 can be set at the side edge of the tab assembly 222, and the connecting structure 235 is set at the middle of the welding part 2221. The pre-welded structure 225 and the connecting structure 235 can also be set on the surface of the welding part 2221 facing the adapter 230 and staggered. The connecting structure 235 can refer to the weld, weld mark, or other structure that welds the welding part 2221 and the adapter 230 together.

[0156] By adopting the technical solution of this embodiment, the multiple tabs 224 in the tab assembly 222 are pre-welded together to form a whole before the tab assembly 222 is bent, thereby reducing the risk of the tab assembly 222 falling apart. In addition, after the tab assembly 222 is bent, the multiple tabs 224 in the tab assembly 222 will fit together more tightly to form a more compact welded part 2221, which is beneficial to improving the welding quality of the tabs 224 and the adapter 230, and is beneficial to improving the performance of the battery cell 20.

[0157] In another embodiment of this application, combined with Figure 9 and Figure 10 As shown, the pre-welded structure 225 is located in the welding part 2221.

[0158] By adopting the technical solution of this embodiment, the pre-welded structure 225 can weld multiple welding segments 2241 in the tab assembly 222 together. In this way, after the tab assembly 222 is bent, the welding part 2221 is not easy to fall apart, and the tab 224 can also form a tight welding part 2221 after bending. This makes the welding quality between the tab 224 and the adapter 230 better, and the performance of the battery cell 20 better. In addition, the pre-welded structure 225 will not weld to the connecting segment 2243, so that the connecting segments 2243 can move relative to each other when the tab assembly 222 is bent, so as to facilitate the bending of the tab 224.

[0159] In another embodiment of this application, combined with Figures 5-7 As shown, the distance between the pre-welded structure 225 and the connecting part 2222 is L2, wherein, .

[0160] By adopting the technical solution of this embodiment, the distance between the pre-welded structure 225 and the connecting section 2243 is within the aforementioned range, and there is a certain distance between the bending point of the tab assembly 222 and the main body 221. In this way, when the tab assembly 222 is bent, the connection between the main body 221 and the tab 224 and the pre-welded structure 225 will not be excessively stretched. On the one hand, this allows the tab assembly 222 to be bent more smoothly, reducing the risk of tab 224 cracking and active material shedding, which is beneficial to improving the yield and performance of the battery cell 20. On the other hand, the pre-welded structure 225 can stably weld multiple welding sections 2241 in the tab assembly 222 together, making the welded part 2221 less likely to fall apart. After the tab 224 is bent, a tight welded part 2221 can also be formed, resulting in better welding quality between the tab 224 and the adapter 230, and better performance of the battery cell 20.

[0161] In another embodiment of this application, combined with Figures 5-7 As shown, .

[0162] By adopting the technical solution of this embodiment, the distance design between the pre-welded structure 225 and the connecting section 2243 is more reasonable, the risk of bending and pulling the tab 224 at the connection between the tab 224 and the main body 221 is reduced, and the tab assembly 222 can be bent more smoothly.

[0163] In one embodiment, the value of L2 can be, but is not limited to, 0.1mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm or 10mm.

[0164] In another embodiment of this application, combined with Figure 9 and Figure 10 As shown, the pre-welded structure 225 is located at the end of the welded part 2221 facing away from the connecting section 2243.

[0165] With the technical solution of this embodiment, before the tab assembly 222 is bent, the ends of the welding section 2241 away from the connecting section 2243 in the tab assembly 222 are welded together, making the welding operation simple, convenient and quick; in addition, when the tab 224 is bent, the part of the welding section 2241 close to the connecting section 2243 can also move with the bending, making the bending operation of the tab assembly 222 more time-saving and labor-saving.

[0166] In another embodiment, the pre-welded structure 225 may also be provided on the side where the welding part 2221 and the connecting part 2222 meet.

[0167] In another embodiment of this application, combined with Figure 9 and Figure 10 As shown, the length of the welded part 2221 is L3, and the length of the pre-welded structure 225 in the length direction of the welded part 2221 is L4, wherein, .

[0168] The length L3 of the welded part 2221 can refer to the length dimension of the welded part 2221 in the length direction (Y direction) of the welded segment 2241.

[0169] The length L4 of the pre-welded structure 225 can refer to the length dimension of the pre-welded structure 225 in the length direction of the welded part 2221.

[0170] By adopting the technical solution of this embodiment, the ratio between the length L4 of the pre-welded structure 225 and the length L3 of the welded part 2221 is within the above range, which enables the pre-welded structure 225 to reliably weld multiple welded segments 2241 in the tab assembly 222 together, reducing the risk of the welded part 2221 becoming loose, and also reducing the risk of other components being damaged due to the pre-welded tab 224.

[0171] In one embodiment, The value can be, but is not limited to, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 0.99.

[0172] In another embodiment of this application, combined with Figure 11 and Figure 12 As shown, the total number of turns of the electrode 223 is N1, and the total number of turns of the electrode 223 connected to the tab 224 is N2. .

[0173] The total number of turns of electrode 223 can refer to the number of turns of electrode 223 wound in electrode assembly 220.

[0174] The total number of turns of the electrode 223 connected to the tab 224 can refer to the sum of the number of turns of the tab 224 led out from the electrode 223 of the electrode assembly 220.

[0175] By adopting the technical solution of this embodiment, the ratio of the total number of turns of the tabs 224 led out from the electrode 223 to the total number of turns of the electrode 223 is within the above-mentioned range, which makes the number of tabs 224 led out from the electrode assembly 220 within a reasonable range. This is beneficial to reducing the internal resistance of the electrode assembly 220 during charging and discharging, and also beneficial to the rapid charging and discharging of the battery cell 20. At the same time, the number of tabs 224 in the tab group 222 led out from the electrode assembly 220 is reasonable, and the tab group 222 is also easy to bend.

[0176] In another embodiment of this application, .

[0177] By adopting the technical solution of this embodiment, the ratio of the total number of turns of the tabs 224 led out from the electrode 223 to the total number of turns of the electrode 223 is more reasonable, and the number of tabs 224 is reasonable, which is beneficial to the rapid charging and discharging of the battery cell 20 and also beneficial to the bending of the tab group 222.

[0178] In one embodiment, The value can be, but is not limited to, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or 0.9.

[0179] In another embodiment of this application, combined with Figure 13 and Figure 14 As shown, the electrode tabs 224 are led out from the end face of the main body portion 221 of the electrode plate 223 at intervals, forming a plurality of electrode tab groups 222, and the plurality of electrode tab groups 222 are arranged at radial intervals along the main body portion 221.

[0180] Understandably, in the radial direction of the main body 221, the electrode plate 223 forms multiple electrode lug groups 222 by intermittently leading out (skipping loop lead-out) electrode tabs 224. Only some loops in the electrode plate 223 lead out to the electrode tabs 224, while the loops in the electrode plate 223 that do not lead out to the electrode tabs 224 are intermittent loops. The absence of electrode tabs 224 in the intermittent loops creates gaps 2223 in the electrode tabs 224 led out by the electrode plate 223. Through the separation of the gaps 2223, the electrode tabs 224 led out by the electrode plate 223 are divided into multiple groups, thus forming multiple electrode lug groups 222. An intermittent gap 2223 is formed between the connecting portions 2222 of two adjacent electrode lug groups 222, and the loops in the electrode plate 223 corresponding to the intermittent gap 2223 are intermittent loops. The spacer ring has no tab 224 extending from the position corresponding to the gap 2223, while the spacer ring may or may not have tab 224 extending from other positions. Before the tab group 222 is bent, the gap 2223 can refer to the gap formed between two adjacent tab groups 222. After the tab group 222 is bent, the gap 2223 refers to the gap formed between the connecting parts 2222 of two adjacent tab groups 222. The spacer ring can refer to the ring in the electrode plate 223 that is opposite to the gap 2223 and does not have tab 224 extending from the gap 2223. That is, all rings in the electrode plate 223 that do not have tab 224 extending into the gap 2223 are spacer rings. The number of spacer rings between two adjacent tab groups 222 can be one, two, three, or more than four, which can be determined according to the way the tab 224 is spaced out by the electrode plate 223.

[0181] Multiple electrode groups 222, which can be understood as the number of electrode groups 222 being multiple, for example, two, three, four or more electrode groups 222.

[0182] The connecting portions 2222 of the multiple tab assemblies 222 are arranged radially spaced along the main body 221. It can be understood that before the tab assemblies 222 are bent, the multiple tab assemblies 222 are arranged radially spaced along the main body 221. After the tab assemblies 222 are bent, the welding portions 2221 are parallel or nearly parallel to the end face of the main body 221, so that the welding portions 2221 of the multiple tab assemblies 222 are stacked along the axial direction of the main body 221 to facilitate welding with the adapter 230. The connecting portions 2222 are perpendicular or nearly perpendicular to the end face of the main body 221, so that the connecting portions 2222 of the multiple tab assemblies 222 are arranged radially spaced along the main body 221.

[0183] By adopting the technical solution of this embodiment, the number of tabs 224 led out from the electrode assembly 220 can be reduced to facilitate the bending of the tabs 224; there are multiple tab groups 222, and the number of tabs 224 in a single tab group 222 is small, making the bending of the tab group 222 simpler and more convenient. By adopting the method of bending the tab group 222 in groups, the bending operation of the tab group 222 is also more time-saving and labor-saving.

[0184] In another embodiment of this application, the number of tabs 224 in the tab group 222 near the inner ring of the electrode 223 is N3, and the number of tabs 224 in the tab group 222 near the outer ring of the electrode 223 is N4, wherein N3 > N4.

[0185] The inner circle of electrode 223 may refer to the first turn of electrode 223, and the inner circle of electrode 223 is set close to the axis away from the main body 221.

[0186] The outer ring of electrode 223 may refer to the last turn of electrode 223, and the outer ring of electrode 223 is set away from the axis of the main body 221.

[0187] By adopting the technical solution of this embodiment, the width of the tabs 224 near the inner ring of the electrode 223 is smaller, and the width of the tabs 224 near the outer ring of the electrode 223 is larger. Furthermore, the number of tabs 224 in the tab group 222 near the inner ring of the electrode 223 is greater than the number of tabs 224 near the outer ring of the electrode 223. That is, the tabs 224 in the tab group 222 near the outer ring of the electrode 223 are sparsely distributed, while the tabs 224 in the tab group 222 near the inner ring of the electrode 223 are densely distributed. The tabs 222 are designed to bend easily. Furthermore, the current-carrying area of ​​the tabs 222 near the outer ring of the electrode 223 is not significantly different from that near the inner ring, which is beneficial for better charging and discharging of the battery cell 20. Also, with the current-carrying area of ​​the tabs 222 near the outer ring of the electrode 223 being the same as that near the inner ring, the tabs 224 in the tabs 222 near the inner ring are not designed to be too wide, thus preventing them from being unable to bend.

[0188] It should be noted that the width of the tab 224 can refer to the circumferential dimension of the tab 224 in the main body 221 before the tab 224 is bent.

[0189] In another embodiment of this application, the number of electrodes 224 in the plurality of electrode groups 222 gradually decreases along a first direction, the first direction being the direction from the inner circle of the electrode 223 to the outer circle of the electrode 223.

[0190] The first direction, for example, can be referred to Figure 14 As shown, it could refer to the X direction.

[0191] The number of tabs 224 in the multiple tab groups 222 gradually decreases along the first direction. It can be understood that the number of tabs 224 in the tab group 222 closer to the inner circle of the electrode plate 223 is more and more, and the number of tabs 224 in the tab group 222 closer to the outer circle of the electrode plate 223 is less and less.

[0192] By adopting the technical solution of this embodiment, the tabs 224 closer to the inner ring of the electrode 223 are generally smaller in width, and the tabs 224 closer to the outer ring of the electrode 223 are also smaller in width. The number of tabs 224 in the tab group 222 closer to the outer ring of the electrode 223 decreases. In this way, the tab group 222 with smaller tab width has more tabs 224, and the tab group 222 with larger tab width has fewer tabs 224. The tab group 222 is easy to bend. In addition, the number of tabs 224 led out from the electrode assembly 220 is also larger, which is conducive to the battery cell 20 achieving faster charging and discharging.

[0193] In another embodiment, the number of electrodes 224 in the plurality of electrode groups 222 can be reduced stepwise along the first direction, that is, there are cases where the number of electrodes 224 in two adjacent electrode groups 222 is the same.

[0194] In another embodiment of this application, combined with Figure 13 and Figure 14 As shown, the distance between the connecting portions 2222 of two adjacent tab groups 222 near the inner ring of the electrode 223 is L5, and the distance between the connecting portions 2222 of two adjacent tab groups 222 near the outer ring of the electrode 223 is L6, where L6 > L5.

[0195] Combination Figure 13 and Figure 14 As shown, before the tab assembly 222 is bent, the distance between the connecting portions 2222 of two adjacent tab assemblies 222 can refer to the distance between two adjacent tab assemblies 222; after the tab assembly 222 is bent, the welding portion 2221 is parallel to the end face of the main body portion 221, and the welding portions 2221 of multiple tab assemblies 222 will be stacked together, but there is a distance between the connecting portions 2222 of two adjacent tab assemblies 222.

[0196] By adopting the technical solution of this embodiment, there are more tab groups 222 near the inner ring of the tab 224 and fewer tab groups 222 near the outer ring of the tab 224. The tabs 224 near the inner ring of the electrode 223 are narrower and the tabs 224 near the outer ring of the electrode 223 are wider. In this way, the current flow area of ​​the electrode assembly 220 near the outer ring of the electrode 223 is not much different from that near the inner ring of the electrode 223, which is beneficial to the better charging and discharging of the battery cell 20. Furthermore, when the current flow area of ​​the electrode assembly 220 near the outer ring of the electrode 223 is the same as that near the inner ring of the electrode 223, the tabs 224 in the tab group 222 near the inner ring will not be designed to be too wide and thus unable to be bent.

[0197] In another embodiment of this application, combined with Figure 13 and Figure 14 As shown, the distance between the connecting portions 2222 of two adjacent electrode groups 222 gradually increases along the first direction, which is the direction from the inner circle of the electrode 223 to the outer circle of the electrode 223.

[0198] The distance between the connecting portions 2222 of two adjacent tab groups 222 gradually increases along the first direction, which is the direction from the inner circle of the electrode 223 to the outer circle of the electrode 223. It can be understood that the number of tab groups 222 closer to the inner circle of the electrode 223 is increasing, and the number of tab groups 222 closer to the outer circle of the electrode 223 is decreasing. The width of the tabs 224 closer to the inner circle of the electrode 223 is smaller, and the length of the tabs closer to the outer circle of the electrode 223 is longer.

[0199] By adopting the technical solution of this embodiment, the number of tab groups 222 closer to the inner ring of the electrode 223 increases, while the number of tab groups 222 closer to the outer ring of the electrode 223 decreases. This makes the difference between the current flow area near the inner ring of the electrode 223 and the current flow area near the outer ring of the electrode 223 smaller, which is beneficial to improving the performance of the battery cell 20.

[0200] In another embodiment, the spacing between the connecting portions 2222 of two adjacent tab groups 222 can be reduced in a stepwise manner along the first direction, that is, there are cases where the spacing between the connecting portions 2222 of two adjacent tab groups 222 is the same.

[0201] In another embodiment of this application, the electrode assembly 220 includes a plurality of tab groups 222, which are arranged at circumferential intervals along the main body 221.

[0202] Multiple tab assemblies 222 can be distributed circumferentially along the main body 221, so that the number of tabs 224 in a single tab assembly 222 can be reduced, which facilitates the bending of the tab assembly 222. Here, a single tab assembly 222 can be obtained by the above-mentioned method of leading out the tabs 224 at intervals, that is, a gap 2223 can be formed in the tab assembly 222, which divides the tab assembly 222 into multiple parts arranged radially along the main body 221. With this design, the number of tabs 224 in the tab assembly 222 can be reduced, which facilitates the bending of the tab assembly 222.

[0203] By adopting the technical solution of this embodiment, the tab group 222 is distributed in a dispersed manner, and the number of tabs 224 in a single tab group 222 can be reduced to facilitate the bending of the tab group 222.

[0204] In another embodiment of this application, combined with Figure 15 As shown, at least one of the welding section 2241 and the connecting section 2243 is provided with a hollow structure 2245.

[0205] At least one of the welding section 2241 and the connecting section 2243 is provided with a hollow structure 2245. It can be understood that the welding section 2241 is provided with a hollow structure 2245; or the connecting section 2243 is provided with a hollow structure 2245; or both the welding section 2241 and the connecting section 2243 are provided with hollow structures 2245. The hollow structure 2245 can refer to a through hole, notch, through groove or other structure on the welding section 2241 or the connecting section 2243.

[0206] By adopting the technical solution of this embodiment, the design of the hollow structure 2245 can reduce the structural strength of the tab 224, thereby facilitating the bending of the tab 224.

[0207] In another embodiment of this application, combined with Figure 15 As shown, when the welding section 2241 is provided with a hollow structure 2245, the welding section 2241 includes a plurality of welding sections 2242 connected to the connecting section 2243. The plurality of welding sections 2242 are arranged at intervals along the length direction of the connecting section 2243, and the gap between two adjacent welding sections 2242 forms a hollow structure 2245.

[0208] The welding segment 2241 is divided into multiple welding sections 2242 along its length. Adjacent welding sections 2242 are disconnected, and a gap is formed between adjacent welding sections 2242, which forms a hollow structure 2245. For example, the welding segment 2241 has multiple through slots (i.e., gaps) that extend through the welding segment 2241 along its height.

[0209] By adopting the technical solution of this embodiment, the welding section 2241 is divided into multiple welding sections 2242 in the length direction of the welding section 2241, and two adjacent welding sections 2242 are disconnected. In this way, when the tab 224 is bent, the width of the welding section 2242 is small, which makes the bending of the tab 224 time-saving and labor-saving.

[0210] In another embodiment of this application, combined with Figure 15 As shown, when the connecting section 2243 is provided with a hollow structure 2245, the connecting section 2243 includes a plurality of connecting sections 2244 connected to the welding section 2241. The plurality of connecting sections 2244 are arranged at intervals along the circumference of the main body 221, and the gap between two connected sections 2244 forms a hollow structure 2245.

[0211] The connecting segment 2243 is divided into multiple connecting sections 2244 in the circumferential direction of the main body 221. Adjacent connecting sections 2244 are disconnected, and a gap is formed between adjacent connecting sections 2244, which forms a hollow structure 2245. For example, the connecting segment 2243 has multiple through slots (i.e., gaps) that penetrate the connecting segment 2243 along the height direction of the connecting segment 2243.

[0212] By adopting the technical solution of this embodiment, the connecting segment 2243 is divided into multiple connecting sections 2244 in the circumferential direction of the main body 221. Two adjacent connecting sections 2244 are disconnected. In this way, when the tab 224 is bent, the width of the connecting section 2244 is small and the structural strength is low, making the bending of the tab 224 convenient and quick.

[0213] In another embodiment of this application, combined with Figure 15 As shown, when both the welding section 2241 and the connecting section 2243 are provided with a hollow structure 2245, multiple welding sections 2242 and multiple connecting sections 2244 are connected one-to-one.

[0214] The welding sections 2242 in the welding section 2241 and the connecting sections 2244 in the connecting section 2243 are connected one-to-one. It can be understood that before the electrode 224 is bent, the electrode 224 has multiple through slots that run through the electrode 224 along the height direction, thereby dividing the electrode 224 into multiple disconnected structures. Each segment includes a welding section 2242 and a connecting section 2244.

[0215] By adopting the technical solution of this embodiment, the electrode 224 is divided into multiple broken structures, the electrode 224 is easy to bend, and the bending process of the electrode 224 is more time-saving and labor-saving.

[0216] In another embodiment of this application, combined with Figures 17-20As shown, the end of the welding portion 2221 facing away from the connecting portion 2222 is located on the side of the connecting portion 2222 facing the inner ring of the tab 224; or, the end of the welding portion 2221 facing away from the connecting portion 2222 is located on the side of the connecting portion 2222 facing away from the inner ring of the tab 224.

[0217] During the bending process of tab 224, tab 224 bends toward the axis of main body 221; after bending, the end of welding part 2221 facing away from connection part 2222 is located on the side of connection part 2222 toward the inner ring of tab 224. This structural design makes the axis of tab 224 toward main body 221 concentrated, with good structural compactness, which is conducive to improving the energy density of battery cell 20.

[0218] During the bending process of tab 224, tab 224 bends away from the axis of the main body 221; after bending, the end of welding part 2221 away from connecting part 2222 is located on the side of connecting part 2222 away from the inner ring of tab 224. This structural design reduces the risk of tab 224 near the outer ring of electrode 223 being drawn towards the axis of the main body 221 and then bent towards the outer ring of electrode 223. This can alleviate the risk of tab 224 near the outer ring of electrode 223 expanding outward, which is beneficial to improving the performance of battery cell 20.

[0219] By adopting the technical solution of this embodiment, the bending direction of the tab 224 can be flexibly set to meet different usage requirements.

[0220] In another embodiment of this application, combined with Figure 7 and Figure 16 As shown, the welding part 2221 is located between the main body 221 and the adapter 230.

[0221] By adopting the technical solution of this embodiment, after the tab 224 is bent, the adapter 230 can be placed on the welding part 2221 for welding, and the assembly operation is simple.

[0222] In another embodiment of this application, combined with Figure 7 and Figure 16 As shown, the battery cell 20 also includes a connector 240, and the connector 240 is welded between the welding part 2221 and the adapter 230; and / or, the welding part 2221 is welded between the connector 240 and the adapter 230.

[0223] The connector 240 can refer to a conductive component that is laminated and welded to the welding part 2221 and the adapter 230. The connector 240 can be located between the welding part 2221 and the adapter 230, between the welding part 2221 and the main body 221, or between the welding part 2221 and the adapter 230 and between the welding part 2221 and the main body 221. The connector 240 can be made of conductive metal, such as copper or aluminum.

[0224] In the actual welding process, after the tab 224 is retracted and before it is bent, the welding section 2241 is in a vertical state. The welding laser welds the connector 240 and the welding section 2241 together in a layered manner along the radial direction of the main body 221. Then, the tab 224 is bent and welded to the adapter 230. The welding laser welds the connector 240 and the welding section 2241 in a direction parallel to the radial direction of the main body 221. This way, even if the welding laser welds through the tab 224 and the connector 240, it will not damage the main body 221, thus improving the yield of the battery cell 20.

[0225] By adopting the technical solution of this embodiment, the connection 240 can increase the welding thickness, reduce the risk of damage to the main body 221 due to weld penetration, and improve the welding quality of the welding part 2221 and the adapter 230.

[0226] In another embodiment of this application, combined with Figure 7 and Figure 8 As shown, the thickness of the welded part 2221 is H1, the thickness of the connector 240 is H2, the number of connectors 240 is N, and the thickness of the welding position between the adapter 230 and the welded part 2221 is H3. .

[0227] The thickness H1 of the welded part 2221 can refer to the dimension of the welded part 2221 in the axial direction of the main body 221; the thickness H1 of the welded part 2221 can also refer to the sum of the thicknesses of all the welded segments 2241 within the welded part 2221.

[0228] The thickness H2 of the connector 240 can refer to the axial dimension of the welded portion 2221 on the main body 221. The number of connectors 240 can be one, two, or more than three, for example... Figure 7As shown, there is one connector 240, which is welded between the welding part 2221 and the adapter 230. Of course, in another embodiment, there may be two connectors 240, one connector 240 is provided on the side of the welding part 2221 facing the main body 221, and the other connector 240 is provided on the side of the welding part 2221 facing the adapter 230. In other embodiments, the side of the welding part 2221 facing the main body 221 may also be provided with a plurality of connectors 240 stacked along the axial direction of the main body 221, or the side of the welding part 2221 facing the adapter 230 may also be provided with a plurality of connectors 240 stacked along the axial direction of the main body 221.

[0229] The welding position of the adapter 230 and the welding part 2221, for example, may refer to the position of the weld mark, weld seam, etc. on the adapter 230 where it is welded to the welding part 2221; the thickness H3 of the welding position of the adapter 230 and the welding part 2221 may refer to the dimension of the welding position of the adapter 230 and the welding part 2221 in the axial direction of the main body 221.

[0230] H1+N×H2 can refer to the sum of the thicknesses of the welded part 2221 and all the connecting parts 240.

[0231] It is understandable that the sum of the thicknesses of the welded part 2221 and all the connecting parts 240 is greater than or equal to the thickness H3 of the welding position between the adapter 230 and the welded part 2221.

[0232] By adopting the technical solution of this embodiment, through The design ensures that the sum of the thicknesses of the welding part 2221 and all the connectors 240 is greater than or equal to the thickness H3 of the welding position between the adapter 230 and the welding part 2221. This makes the sum of the thicknesses of the welding part 2221 and all the connectors 240 larger than the thickness of the welding position of the welding part 2221, making it less likely for the welding part 2221 and the connectors 240 to be welded through. This reduces damage to the main body 221, improves welding quality, and increases the yield of the battery cell 20.

[0233] In one embodiment, The value can be, but is not limited to, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1.

[0234] In another embodiment of this application, combined with Figure 7 and Figure 8 As shown, when a connector 240 is welded between the welded part 2221 and the adapter 230, the thickness H1 of the welded part 2221 is greater than the thickness H2 of the connector 240.

[0235] By adopting the technical solution of this embodiment, when welding the welding part 2221 and the adapter 230, since the connector 240 is located between the welding part 2221 and the adapter 230, the welding part 2221 is welded from the connector 240. Since the thickness H1 of the welding part 2221 is greater than the thickness H2 of the connector 240, the welding part 2221 is not easily welded through, reducing the risk of damage to the main body 221 and improving the welding quality and the yield of the battery cell 20.

[0236] In another embodiment of this application, combined with Figure 7 and Figure 8 As shown, the thickness of connector 240 is H2, where 0.2mm≤H2≤0.4mm.

[0237] By adopting the technical solution of this embodiment, the thickness H2 of the connector 240 is set within the range of 0.2mm to 0.4mm. The thickness H2 of the connector 240 is set reasonably. On the one hand, it can reduce the risk of damage to the main body 221 caused by the weld 2221 being welded through. On the other hand, the connector 240 will not occupy too much space, which is conducive to improving the volumetric energy density of the battery cell 20. With this design, the thickness H2 of the connector 240 will not be too small, which would easily cause the connector 240 and the weld 2221 to be welded through. The thickness H2 of the connector 240 will not be too large, which would occupy too much space of the battery cell 20.

[0238] In another embodiment of this application, combined with Figures 17-20 As shown, the adapter 230 is located between the welding part 2221 and the main body part 221.

[0239] By adopting the technical solution of this embodiment, the adapter 230 is located between the welding part 2221 and the main body 221. In this way, during welding, the adapter 230 is welded from the welding part 2221. The structural strength of the adapter 230 is usually better than that of the welding part 2221, making the adapter 230 less likely to be welded through, thereby reducing the risk of damage to the main body 221 and improving the welding quality and the yield of the battery cell 20.

[0240] In another embodiment of this application, combined with Figure 17 , Figure 18 and Figure 21 As shown, the adapter 230 is provided with a through hole 231, and the connecting part 2222 passes through the through hole 231.

[0241] The through hole 231 can refer to the through hole structure provided in the adapter 230, which allows the tab assembly 222 to pass through. In the actual assembly process, after the tab assembly 222 passes through the through hole 231, it bends on the axis toward or away from the main body 221.

[0242] By adopting the technical solution of this embodiment, after the tab assembly 222 passes through the through hole 231 and bends, the welding part 2221 is located on the side of the adapter 230 facing away from the main body 221. Under the action of the adapter 230, the main body 221 is not easily damaged by welding, which is conducive to improving the welding quality and the yield of the battery cell 20.

[0243] In another embodiment of this application, combined with Figure 19 , Figure 20 and Figure 21 As shown, when the end of the welding part 2221 facing away from the connecting part 2222 is located on the side of the connecting part 2222 close to the inner ring of the tab 224, the connecting part 2222 is located on the side of the adapter 230 close to the outer ring of the electrode 223.

[0244] During assembly, the adapter 230 is placed on the side of the tab assembly 222 near the inner ring of the tab 224, and then the tab assembly 222 is bent toward the axis of the main body 221. After bending, the welding part 2221 is located on the side of the adapter 230 away from the main body 221, the connecting part 2222 is located on the side of the adapter 230 near the outer ring of the electrode 223, and the end of the welding part 2221 away from the connecting part 2222 is located on the side of the connecting part 2222 near the inner ring of the tab 224.

[0245] By adopting the technical solution of this embodiment, the tab assembly 222 passes directly through the side of the adapter 230 near the outer ring of the electrode 223 and then bends, so that the welding part 2221 can be located on the side of the adapter 230 away from the main body 221. This eliminates the need to open a through structure in the adapter 230, which is convenient for processing and manufacturing.

[0246] In another embodiment of this application, combined with Figure 19 , Figure 20 and Figure 21 As shown, the adapter 230 has a notch 232 on the side near the outer ring of the electrode 223, and the connecting part 2222 is located inside the notch 232.

[0247] The notch 232 can refer to a notch 232 structure used to avoid or accommodate the connecting part 2222. The shape of the notch 232 can be various, such as U-shaped; for example, a portion of material can be removed from the periphery of the adapter 230 in a straight line to form the notch 232, which is simple and convenient to manufacture.

[0248] By adopting the technical solution of this embodiment, the notch 232 can provide installation space for the connecting part 2222. The connecting part 2222 is not likely to protrude beyond the outer peripheral wall of the main body 221. A certain distance can also be maintained between the connecting part 2222 and the inner wall of the outer shell 210, reducing the risk of compression between the connecting part 2222 and the inner wall of the outer shell 210. This is beneficial to improving the reliability of the battery cell 20 and the overall structure is compact, which is beneficial to improving the energy density of the battery cell 20.

[0249] In another embodiment of this application, combined with Figures 22-24 As shown, the battery cell 20 includes multiple tab groups 222. The welding portion 2221 of a portion of the tab group 222 is located between the main body 221 and the adapter 230; the welding portion 2221 of another portion of the tab group 222 is located on the side of the adapter 230 facing away from the main body 221.

[0250] By adopting the technical solution of this embodiment, the electrode tabs 224 of the electrode assembly 220 are divided into multiple tab groups 222, so that the number of tabs 224 in each tab group 222 can be designed to be smaller to facilitate bending; in addition, the position of the welding part 2221 of the tab group 222 can also be flexibly set, making assembly simpler and more convenient.

[0251] In one embodiment, the adapter 230 includes a flip-up portion 233 and a fixing portion 234 connected to each other. The flip-up portion 233 is welded to the welding portion 2221, and the flip-up portion 233 is capable of flipping relative to the fixing portion 234.

[0252] For example Figure 25 As shown, the flipping part 233 can refer to the part where the adapter 230 is welded to the welding part 2221, and the fixing part 234 can refer to the part of the adapter 230 other than the flipping part 233. The fixing part 234 and the flipping part 233 are connected by... Figure 25The dotted line serves as a dividing line. The flipping part 233 can be flipped upward relative to the fixed part 234 along the dotted line. This allows the flipping part 233 to be flipped upward before the tab assembly 222 is bent, so that the fixed part 234 and the flipping area are at a certain angle. At this time, the welding laser can weld the welding part 2221 and the flipping part 233 together along the radial direction of the main body 221. This way, even if the welding laser penetrates the welding part 2221, it will not hit the main body 221 and damage it, reducing the risk of damage to the main body 221. After welding, the flipping part 233 and the tab assembly 222 are flipped together, so that the welding part 2221 and the flipping part 233 are stacked along the axial direction of the main body 221. Finally, the electrode assembly 220 and the adapter 230 after welding are fixed and installed into the housing 210. In this embodiment, the fixing part 234 and the flipping part 233 are integrated components, achieved by the bending capability of the material of the adapter 230 itself; alternatively, the fixing part 234 and the flipping part 233 can be fixedly connected, and the bending capability of the material of the flipping part 233 itself can be achieved; or it can be achieved through a rotating structure connecting the fixing part 234 and the flipping part 233; the rotating structure can be a shaft structure, a hinge structure, or a bendable component (such as a copper sheet, aluminum sheet, etc.). One adapter 230 can have multiple flipping parts 233, which are welded one-to-one with the tab assembly 222. In another embodiment, one flipping part 233 can be welded to multiple tab assemblies 222.

[0253] By adopting the design scheme of this embodiment, the welding direction of the welding laser can be changed, thereby reducing the risk that the welding laser will penetrate the welded part 2221 without hitting the main body 221 and damaging it, thus improving the performance of the battery cell 1100. The structure of the battery cell 20 will be described below with reference to some specific embodiments. Specific Implementation Example 1 In this specific embodiment, combined with Figures 4-10As shown, the battery cell 20 includes a housing 211, an electrode assembly 220, and an adapter 230. Both the electrode assembly 220 and the adapter 230 are located within the mounting cavity 2111 of the housing 210. The electrode assembly 220 includes a main body 221 and a tab assembly 222. The main body 221 is a cylindrical structure formed by winding electrode sheets 223. At least two loops of the electrode sheets 223 extend from the end face of the main body 221, and multiple tabs 224 arranged radially along the main body 221 form the tab assembly 222. The tab assembly 222 is bent towards the end of the main body 221. After bending, the tabs 224 in the tab assembly 222 form a welding section 2241 and a connecting section 2243. The connecting section 2243 connects the main body 221 and the welding section 2241, and the connecting section 2243 is curved. The multiple tabs in the tab assembly 222... The welding segments 2241 of 224 are stacked along the axial direction of the main body 221 to form a welding portion 2221. The connecting segments 2243 of the multiple electrodes 224 in the electrode lug assembly 222 are stacked along the radial direction of the main body 221 to form a connecting portion 2222. The adapter 230 and the welding portion 2221 are stacked along the axial direction of the main body 221, and the adapter 230 is welded to the welding portion 2221. The end of the welding portion 2221 facing away from the connecting portion 2222 is provided with a pre-welded structure 225 to stably connect the electrodes 224 together, which helps to form a dense welding portion 2221 and improve the welding quality. The welding portion 2221 is located between the main body 221 and the adapter 230, and a connector 240 is welded between the adapter 230 and the welding portion 2221 to increase the welding thickness, reduce the risk of weld burn-through, reduce welding defects, and improve the welding quality. Specific Implementation Example 2 In this specific embodiment, combined with Figure 11 and Figure 12 As shown, the difference between this specific embodiment and specific embodiment 1 is that the length L1 of the connecting section 2243 is less than the length L7 of the welding section 2241, which facilitates the bending of the tab 224. Specific Implementation Example 3 In this specific embodiment, combined with Figure 13 and Figure 14 As shown, this specific embodiment differs from specific embodiment 1 in that: the electrode assembly 220 has multiple tab groups 222, which are arranged radially at intervals along the main body 221, and the spacing between adjacent tab groups 222 increases along a first direction, which is the direction from the inner ring of the electrode 223 to the outer ring of the electrode 223. The tabs 224 are divided into multiple groups, so the number of tabs 224 in each tab group 222 can be set to be smaller, which facilitates the bending of the tab group 222. In addition, the reasonable arrangement of multiple tab groups 222 can also take into account the current flow area of ​​the inner and outer rings of the electrode 223, thereby improving the performance of the battery cell 20. Specific Implementation Example 4 In this specific embodiment, combined with Figure 15 As shown, the difference between this specific embodiment and specific embodiment 1 is that: the tab assembly 222 is divided into multiple segments along the width direction of the tab 224, and the adjacent segments are completely disconnected, so that the welding segment 2241 of the tab 224 is divided into multiple completely disconnected welding segments 2242, and the connecting segment 2243 of the tab 224 is divided into multiple completely disconnected connecting segments 2244. The welding segments 2242 and the connecting segments 2244 are connected one-to-one. The gap between two adjacent welding segments 2242 forms a hollow structure 2245, and the gap between two adjacent connecting segments 2244 forms a hollow structure 2245. This multi-segment structure design facilitates the bending of the tab assembly 222. Specific Implementation Example 5 In this specific embodiment, combined with Figure 16 As shown, the difference between this specific embodiment and specific embodiment 1 is that the connector 240 is located between the welding part 2221 and the main body part 221. On the one hand, the setting of the connector 240 increases the welding thickness and reduces the risk of welding through and damaging the main body part 221. On the other hand, the structural strength of the connector 240 is usually better than that of the welding part 2221. In this way, the connector 240 is not easy to weld through and damage the main body part 221 during welding, which is conducive to improving the welding quality and the yield of the battery cell 20. Specific Implementation Example 6 In this specific embodiment, combined with Figure 17 , Figure 18 and Figure 21 As shown, the difference between this specific embodiment and specific embodiment 1 is that the battery cell 20 does not include the connector 240, the adapter 230 has a through hole 231, the tab assembly 222 passes through the through hole 231 and bends towards the outer ring of the electrode 223; after bending, the welding part 2221 is located on the side of the adapter 230 away from the main body 221, and the connector 2222 passes through the through hole 231. Usually, the structural strength of the adapter 230 is better than that of the welding part 2221. In this way, the connector 240 is not easily welded through and damaged by the main body 221 during welding, which is beneficial to improving the welding quality and the yield of the battery cell 20. Specific Implementation Example 7 In this specific embodiment, combined with Figure 19 , Figure 20 and Figure 21As shown, the difference between this specific embodiment and specific embodiment 6 is that: the adapter 230 has a notch 232 near the outer ring of the electrode 223, and the electrode lug 222 passes through the notch 232 and bends toward the inner ring of the electrode 223; after bending, the welding part 2221 is located on the side of the adapter 230 away from the main body 221, and the connecting part 2222 passes through the notch 232. Specific Implementation Example 8 In this specific embodiment, combined with Figure 22 As shown, the difference between this specific embodiment and specific embodiment 6 is that: the electrode assembly 220 leads out two tab assemblies 222, and the adapter 230 has a notch 232 and a through hole 231. One tab assembly 222 passes through the notch 232 and bends towards the inner ring of the electrode plate 223. After bending, the welding part 2221 of the tab assembly 222 is located on the side of the adapter 230 away from the main body 221, and the connecting part 2222 of the tab assembly 222 passes through the notch 232. The other tab assembly 222 passes through the through hole 231 and bends towards the outer ring of the electrode plate 223. After bending, the welding part 2221 of the tab assembly 222 is located on the side of the adapter 230 away from the main body 221, and the connecting part 2222 of the tab assembly 222 passes through the through hole 231. Specific Implementation Example 9 In this specific embodiment, combined with Figure 23 As shown, the difference between this specific embodiment and specific embodiment 8 is that: the adapter 230 has a notch 232, and one of the tabs 222 passes through the notch 232 and bends towards the inner ring of the electrode 223. After bending, the welding part 2221 of the tab 222 is located on the side of the adapter 230 away from the main body 221, and the connecting part 2222 of the tab 222 passes through the notch 232. The other tab 222 is located between the adapter 230 and the main body 221, and the tab 222 bends towards the outer ring of the electrode 223; after bending, the welding part 2221 of the tab 222 is located between the adapter 230 and the main body 221. Specific Implementation Example 10 In this specific embodiment, combined with Figure 23 As shown, the difference between this specific embodiment and specific embodiment 8 is that the electrode assembly 220 also leads out a set of tabs 222, which is located between the adapter 230 and the main body 221. The tabs 222 are bent toward the outer ring of the electrode 223. After bending, the welding part 2221 of the tabs 222 is located between the adapter 230 and the main body 221.

[0264] In another embodiment of this application, combined with Figures 4-10As shown, a method for manufacturing a battery cell 20 is provided, which is used to manufacture the battery cell 20 as described in the above embodiment. The method for manufacturing the battery cell 20 includes the following steps: The tab group 222 of the electrode assembly 220 is bent toward the end of the main body 221 of the electrode assembly 220. The main body 221 is a cylindrical structure formed by winding the electrode sheet 223. At least two loops of the electrode sheet 223 lead out of the end face of the main body 221 with tabs 224. Multiple tabs 224 arranged radially along the main body 221 are formed by the tab group 222. After the tabs 224 in the tab group 222 are bent, they form welding sections 2241 and connecting sections 2243. The welding sections 2241 of the multiple tabs 224 are stacked along the axial direction of the main body 221 to form a welding portion 2221. The connecting sections 2243 of the multiple tabs 224 are stacked along the radial direction of the main body 221 to form a connecting portion 2222. The adapter 230 is welded to the welding part 2221, and the adapter 230 and the welding part 2221 are stacked along the axial direction of the main body 221; The welded adapter 230 and electrode assembly 220 are installed into the mounting cavity 2111 of the housing 210.

[0265] The battery cell 20 manufacturing method of this application embodiment first bends the tab assembly 222 to form a welding part 2221 and a connecting part 2222, then welds the welding part 2221 to the adapter 230, and finally the welded electrode assembly 220 and the adapter 230 are installed into the mounting cavity 2111 of the housing 210. In this process, the welding part 2221 formed after bending the tab assembly 222 can be flatly and tightly fitted together to form a tight welding part 2221, thereby reducing the problem of poor welding between the welding part 2221 and the adapter 230, which is beneficial to improving the performance of the battery cell 20.

[0266] In another embodiment of this application, combined with Figure 9 and Figure 10 As shown, before the tab assembly 222 is bent, the tab assembly 222 is gathered along the stacking direction of the welding section 2241.

[0267] Before the tab assembly 222 is bent, please refer to Figure 9 As shown, the stacking direction of the welding segment 2241 can refer to the radial direction of the main body 221.

[0268] By adopting the technical solution of this embodiment, the compression and gathering can make the bent welding section 2241 fit together more tightly to form a tighter welding part 2221, reducing the risk of welding defects such as incomplete welding and weld penetration, and is more conducive to improving the welding quality of the adapter 230 and the tab 224.

[0269] In another embodiment of this application, combined with Figure 11 and Figure 12 As shown, after the tab 224 is folded up and before the tab 224 is bent, the tab assembly 222 is pre-welded so that the tabs 224 in the tab assembly 222 are welded together.

[0270] By adopting the technical solution of this embodiment, after the tab 224 is folded up and before the tab 224 is bent, the tabs 224 in the tab assembly 222 are welded together by pre-welding. This reduces the risk of the tabs 224 loosening after bending, and allows the welding segments 2241 in the subsequent welding part 2221 to fit together to form a tight welding part 2221, thereby reducing the risk of poor welding such as incomplete welding and burn-through, and improving the welding quality between the welding part 2221 and the adapter 230.

[0271] In another embodiment of this application, combined with Figure 9 and Figure 10 As shown, the end of the pre-welded tab assembly 222 facing away from the main body 221.

[0272] By adopting the technical solution of this embodiment, pre-welding is performed on the end of the tab assembly 222 facing away from the main body 221. After welding, the end of the tab assembly 222 near the main body 221 is in a free state, so as to facilitate the bending of the tab assembly 222.

[0273] In another embodiment of this application, combined with Figure 2 As shown, a battery 1100 is provided, including a battery cell 20 as described in the above embodiments, and / or including a method for obtaining the battery cell 20 using the battery cell 20 manufacturing method described in the above embodiments.

[0274] In another embodiment of this application, combined with Figure 1 As shown, an electrical device is provided, including a battery 1100 as described in the above embodiment.

[0275] The description of the various embodiments above tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referred to, and for the sake of brevity, they will not be repeated here.

[0276] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A single battery cell, characterized in that: include, The outer casing has a mounting cavity; An electrode assembly, located in the mounting cavity, includes a main body and a tab assembly. The main body is a cylindrical structure formed by winding an electrode sheet. At least two loops of the electrode sheet extend from the end face of the main body, and multiple tabs arranged radially along the main body form the tab assembly. The tab assembly is bent toward the end of the main body, and the bent tabs form a welding section and a connecting section. The connecting section connects the main body and the welding section, and the connecting section is curved. The welding sections of the multiple tabs in the tab assembly are stacked axially along the main body to form a welding portion, and the connecting sections of the multiple tabs in the tab assembly are stacked radially along the main body to form a connecting portion. An adapter is stacked with the welding part along the axial direction of the main body, and the adapter is welded to the welding part.

2. The battery cell according to claim 1, characterized in that: The length of the connecting segment is L1, and the radius of the circle in the electrode that connects to the connecting segment is R, wherein...

3. The battery cell according to claim 2, characterized in that:

4. The battery cell according to any one of claims 1 to 3, characterized in that: The length of the connecting segment in at least one of the tabs is less than the length of the welding segment.

5. The battery cell according to any one of claims 1 to 4, characterized in that: The tab assembly is provided with a pre-welded structure, which is used to connect multiple tabs in the tab assembly.

6. The battery cell according to claim 5, characterized in that: The pre-welded structure is located at the welding section.

7. The battery cell according to claim 6, characterized in that: The distance between the pre-welded structure and the connecting part is L2, wherein 0.1mm≤L2≤10mm.

8. The battery cell according to claim 6, characterized in that: 0.5mm≤L2≤10mm.

9. The battery cell according to any one of claims 5 to 8, characterized in that: The pre-welded structure is located at the end of the welded section opposite to the connecting section.

10. The battery cell according to claim 9, characterized in that: The length of the welded portion is L3, and the length of the pre-welded structure is L4 along the length direction of the welded portion.

11. The battery cell according to any one of claims 1 to 10, characterized in that: The total number of turns of the electrode plate is N1, and the total number of turns of the electrode plate connected to the electrode tab is N2, wherein...

12. The battery cell according to claim 11, characterized in that:

13. The battery cell according to any one of claims 1 to 12, characterized in that: The electrode plates are led out from the end face of the main body at intervals to form a plurality of electrode tab groups, and the connecting portions of the plurality of electrode tab groups are arranged at intervals along the radial direction of the main body.

14. The battery cell according to claim 13, characterized in that: The number of tabs in the tab group near the inner ring of the electrode plate is N3, and the number of tabs in the tab group near the outer ring of the electrode plate is N4, wherein N3 > N4.

15. The battery cell according to claim 14, characterized in that: The number of electrodes in the plurality of electrode groups gradually decreases along a first direction, the first direction being the direction from the inner circle of the electrode to the outer circle of the electrode.

16. The battery cell according to any one of claims 13 to 15, characterized in that: The distance between the connecting portions of two adjacent tab groups near the inner ring of the electrode is L5, and the distance between the connecting portions of two adjacent tab groups near the outer ring of the electrode is L6, wherein L6 > L5.

17. The battery cell according to claim 16, characterized in that: The distance between the connecting portions of two adjacent electrode groups gradually increases along a first direction, which is the direction from the inner ring of the electrode to the outer ring of the electrode.

18. The battery cell according to any one of claims 1 to 17, characterized in that: The electrode assembly includes a plurality of electrode tabs, which are spaced apart circumferentially along the main body.

19. The battery cell according to any one of claims 1 to 18, characterized in that: At least one of the welding section and the connecting section has a hollow structure.

20. The battery cell according to claim 19, characterized in that: When the welding section is provided with the hollow structure, the welding section includes a plurality of welding sections connected to the connecting section, the plurality of welding sections are arranged at intervals along the length direction of the connecting section, and the gap between two adjacent welding sections forms the hollow structure; When the connecting section is provided with the hollow structure, the connecting section includes multiple connecting sections connected to the welding section. The multiple connecting sections are arranged at intervals along the circumference of the main body, and the gap between two connected sections forms the hollow structure.

21. The battery cell according to claim 20, characterized in that: When both the welding section and the connecting section are provided with the hollow structure, the multiple welding sections and the multiple connecting sections are connected in a one-to-one correspondence.

22. The battery cell according to any one of claims 1 to 21, characterized in that: The end of the welded portion facing away from the connecting portion is located on the side of the connecting portion facing the inner ring of the tab; or, the end of the welded portion facing away from the connecting portion is located on the side of the connecting portion facing away from the inner ring of the tab.

23. The battery cell according to any one of claims 1 to 22, characterized in that: The welded part is located between the main body and the adapter.

24. The battery cell according to claim 23, characterized in that: The battery cell further includes a connector, and the connector is welded between the welding part and the adapter; and / or, the welding part is welded between the connector and the adapter.

25. The battery cell according to claim 24, characterized in that: The thickness of the welded part is H1, the thickness of the connector is H2, the number of connectors is N, and the thickness of the welding position between the adapter and the welded part is H3. Among them, among them, 26. The battery cell according to claim 24 or 25, characterized in that: When the connecting member is welded between the welded part and the adapter, the thickness of the welded part is greater than the thickness of the connecting member.

27. The battery cell according to any one of claims 23 to 26, characterized in that: The thickness of the connector is H2, wherein 0.2mm≤H2≤0.4mm.

28. The battery cell according to any one of claims 1 to 22, characterized in that: The adapter is located between the welded part and the main body.

29. The battery cell according to claim 28, characterized in that: The adapter is provided with a through hole, and the connecting part passes through the through hole.

30. The battery cell according to claim 28, characterized in that: When the end of the welded portion facing away from the connecting portion is located on the side of the connecting portion near the inner ring of the electrode tab, the connecting portion is located on the side of the adapter near the outer ring of the electrode plate.

31. The battery cell according to claim 30, characterized in that: The adapter has a notch on the side near the outer ring of the electrode, and the connecting part is located inside the notch.

32. The battery cell according to any one of claims 1 to 31, characterized in that: The battery cell includes multiple electrode groups, with the welded portion of a portion of the electrode groups located between the main body and the adapter; the welded portion of another portion of the electrode groups is located on the side of the adapter facing away from the main body.

33. The battery cell according to any one of claims 1 to 32, characterized in that: The adapter includes a flip-up part and a fixing part connected to each other. The flip-up part is welded to the welding part, and the flip-up part is capable of flipping relative to the fixing part.

34. A battery, characterized in that: Includes the battery cell according to any one of claims 1 to 33.

35. An electrical device, characterized in that: Includes the battery as described in claim 34.

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