Battery cell and manufacturing method therefor, and battery and electric device

Abstract

Disclosed in the present application are a battery cell and a manufacturing method therefor, and a battery and an electric device. The battery cell comprises a casing, and an adapter and an electrode assembly, which are arranged in the casing, wherein the electrode assembly comprises a main body portion and tab groups; the main body portion is of a cylindrical structure formed by winding an electrode sheet; tabs are led out of at least two circles in the electrode sheet from an end face of the main body portion; a plurality of tabs arranged in the radial direction of the main body portion are led out of the electrode sheet to form the tab groups; the tab groups are bent towards an end portion of the main body portion; the tabs in the tab groups are bent to form welding sections and connecting sections; the connecting sections are connected between the main body portion and the welding sections, and are bent; the welding sections of the plurality of tabs in the tab groups are stacked in the axial direction of the main body portion and form welding portions; the connecting sections of the plurality of tabs in the tab groups are stacked in the radial direction of the main body portion and form connecting portions; and the welding portions can form dense welding structures to be welded with the adapter. Therefore, the welding quality of the tabs and the adapter can be improved.

Description

Battery cell and manufacturing method thereof, battery and power-consuming device

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on June 30, 2023, with application number 202310791898.8 and invention name “Battery Cell and Method for Making It, Battery and Electrical Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of battery manufacturing, and in particular to a battery cell and a manufacturing method thereof, a battery, and an electrical device. Background Art

[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 a crucial component of the industry's sustainable development. Battery technology, in turn, is a crucial factor in the development of electric vehicles. The tabs leading from the electrode assemblies within battery cells are typically welded to adapters. However, poor welding between the tabs and adapters can easily affect the performance of the battery cells.

[0004] The above statements are only used to provide background information related to the present application and do not necessarily constitute prior art.

[0005] Application Contents

[0006] The purpose of the present application is to provide a battery cell and a manufacturing method thereof, a battery and an electrical device, which can reduce the risk of poor welding between the tab and the adapter, and is conducive to improving the performance of the battery cell.

[0007] The technical solution adopted in the embodiment of this application is:

[0008] In a first aspect, a battery cell is provided, which includes a shell, an adapter and an electrode assembly, the shell having an installation cavity; the electrode assembly is located in the installation cavity, the electrode assembly includes a main body and a tab group, the main body is a cylindrical structure formed by winding a pole sheet, at least two turns of the pole sheet lead out a tab from the end face of the main body, and the pole sheet leads out a plurality of tabs arranged radially along the main body to form a tab group; the tab group is bent toward the end of the main body, and the tabs in the tab group are bent to form a welding section and a connecting section, the connecting section is connected between the main body and the welding section, and the connecting section is curved; the welding sections of the plurality of tabs in the tab group are stacked along the axial direction of the main body to form a welding portion, and the connecting sections of the plurality of tabs in the tab group 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.

[0009] In the battery cell of the embodiment of the present application, after the electrode assembly is wound, the end of the main body of the electrode assembly is led out to the tab group to be bent, and the tabs in the tab group are bent to form welding sections and connecting sections; and after the tab group is bent, the welding sections of multiple tabs in the tab group are stacked along the axial direction of the main body to form a welding portion, and the connecting sections of multiple tabs in the tab group are stacked along the radial direction of the main body, and then the adapter is welded to the welding portion, thus completing the welding of the tab and the adapter. In this process, after the tab is bent, the welding sections of multiple tabs in the tab group can be stacked together flatly to form a tight welding portion, thereby reducing the problem of poor welding between the welding portion and the adapter, which is beneficial to improving the performance of the battery cell.

[0010] In one embodiment, the length of the connecting section is L1, and the radius of a circle of the pole piece corresponding to the connecting section is R, wherein,

[0011] By adopting the technical solution of this embodiment, the curvature of the tabs corresponding to the circles of different radii in the electrode piece can be controlled not to be too large, thereby facilitating the folding and bending of the tabs. In addition, the folding and bending of the tabs generate little pulling force on the main body, reducing the risks of tab cracking and active material shedding, which is beneficial to improving the yield and performance of the battery cells.

[0012] In one embodiment,

[0013] By adopting the technical solution of this embodiment, the curvature of the pole ear caused by the circles corresponding to different radii of the pole piece is smaller, making the folding and bending of the pole ear simpler and more labor-saving, and the pulling force generated by the folding and bending of the pole ear on the main body is smaller, which can effectively reduce the risks of cracking of the connection and falling off of the active material, and effectively improve the yield and performance of the battery cell.

[0014] In one embodiment, the length L1 of the connecting segment in at least one tab is smaller than the length of the welding segment.

[0015] By adopting the technical solution of this embodiment, the connecting section is shorter than the welding section, and the folding and bending of the tab is simpler and faster, which is conducive to the folding and bending of the tab.

[0016] In one embodiment, the tab group is provided with a pre-welding structure, and the pre-welding structure is used to connect multiple tabs in the tab group.

[0017] By adopting the technical solution of this embodiment, the multiple tabs in the tab group are pre-welded together to form a whole before the tab group is bent, thereby reducing the risk of the tab group becoming loose. In addition, after the tab group is bent, the multiple tabs in the tab group will fit together more tightly to form a tighter 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.

[0018] In one embodiment, a pre-welding structure is provided at the welding portion.

[0019] By adopting the technical solution of this embodiment, the pre-welding structure can weld together multiple welding sections in the tab group, so that after the tab group is bent, the welding part is not easy to fall apart, and a tight welding part can be formed after the tab is bent, so that the welding quality between the tab and the adapter is better, and the performance of the battery cell is better; in addition, the pre-welding structure will not limit the connecting section, so that the connecting sections can move relative to each other when the tab group is bent, so as to facilitate the bending of the tab.

[0020] In one embodiment, the distance between the pre-welded structure and the connecting portion is L2, wherein 0.1 mm≤L2≤10 mm.

[0021] By adopting the technical solution of this embodiment, the distance between the pre-welding structure and the connecting part is reasonable, which is conducive to the bending of the tab group. At the same time, the pre-welding structure can stably weld multiple welding sections in the tab group together, so that the welding part is not easy to spread out to form a tight welding part, thereby improving the welding quality between the tab and the adapter and improving the performance of the battery cell.

[0022] In one embodiment, 0.5 mm ≤ L2 ≤ 10 mm.

[0023] By adopting the technical solution of this embodiment, the distance design between the pre-welded structure and the connecting section is more reasonably designed, and the risk of the tab bending and pulling the connection between the tab and the main body is reduced, so that the tab group can be bent more smoothly.

[0024] In one embodiment, the pre-welding structure is located at an end of the welding portion facing away from the connecting section.

[0025] Through the technical solution of this embodiment, before the tab group is bent, the ends of the welding sections in the tab group away from the connecting sections are welded together, and the welding operation is simple, convenient and fast. In addition, when the tab is bent, the part of the welding section close to the connecting section can also move with the bending, making the bending operation of the tab group more time-saving and labor-saving.

[0026] In one embodiment, the length of the welding portion is L3, and the length of the pre-welded structure in the length direction of the welding portion is L4, wherein,

[0027] By adopting the technical solution of this embodiment, the ratio between the length L4 of the pre-welding structure and the length L3 of the welding portion is within the above range, so that the pre-welding structure can reliably weld together multiple welding sections in the tab group, reducing the risk of the welding portion becoming loose due to the length L4 of the pre-welding structure being too short, and also reducing the risk of the tab being welded out due to the length L4 of the pre-welding structure being too long.

[0028] In one embodiment, the total number of turns of the pole piece is N1, and the total number of turns of the pole piece connected to the pole lug is N2, wherein,

[0029] By adopting the technical solution of this embodiment, the ratio of the total number of tabs extending from the electrode sheet to the total number of tabs extending from the electrode sheet falls within the aforementioned range, allowing the electrode assembly to extend more tabs, thereby reducing the internal resistance of the electrode assembly during charging and discharging. If the number of tabs extending from the electrode assembly is small, the internal resistance of the electrode assembly during charging is high, which is not conducive to rapid charging and discharging of the battery cells. If the number of tabs within the tab group extending from the electrode assembly is too large, the tab group is not easily bent.

[0030] In one embodiment,

[0031] By adopting the technical solution of this embodiment, the ratio of the total number of turns of the tabs extending from the pole piece to the total number of turns of the pole piece is more reasonable, and the number of tabs is reasonable, which is beneficial to the rapid charging and discharging of the battery cell and the bending of the tab group.

[0032] In one embodiment, the pole pieces extend the pole tabs from the end surface of the main body at intervals to form a plurality of pole tab groups, and the connecting portions of the plurality of pole tab groups are arranged at intervals along the radial direction of the main body.

[0033] By adopting the technical solution of this embodiment, the number of tabs led out of the electrode assembly can be reduced to facilitate the bending of the tabs; the number of tab groups is multiple, and the number of tabs in a single tab group is small, so the bending of the tab group is simpler and more convenient. In this way, the method of bending the tab groups in groups is adopted, and the bending operation of the tab group is also more time-saving and labor-saving.

[0034] In one embodiment, the number of tabs in the tab group close to the inner circle of the pole piece is N3, and the number of tabs in the tab group close to the outer circle of the pole piece is N4, wherein N3>N4.

[0035] By adopting the technical solution of this embodiment, the tab group is easy to bend; in addition, the flow area of ​​the tab group close to the outer ring of the pole piece and the flow area of ​​the tab group close to the inner ring of the pole piece are not much different, which is conducive to better charging and discharging of the battery cell; and, when the flow area of ​​the tab group close to the outer ring of the pole piece and the flow area of ​​the tab group close to the inner ring of the pole piece are the same, the tabs in the tab group close to the inner ring will not be designed to be too wide and cannot be bent.

[0036] In one embodiment, the number of tabs in the plurality of tab groups gradually decreases along a first direction, where the first direction is a direction from the inner circle of the pole piece to the outer circle of the pole piece.

[0037] By adopting the technical solution of this embodiment, the smaller the tab width, the more tabs there are in the tab group, and the larger the tab width, the smaller the tab number there are in the tab group, and the tab group is simpler to bend; in addition, the number of tabs led out of the electrode assembly is also large, which is conducive to faster charging and discharging of the battery cells.

[0038] In one embodiment, the distance between the connecting portions of two adjacent tab groups near the inner circle of the pole piece is L5, and the distance between the connecting portions of two adjacent tab groups near the outer circle of the pole piece is L6, wherein L6>L5.

[0039] By adopting the technical solution of this embodiment, the number of pole lug groups near the inner ring of the pole lug is large, while the number of pole lug groups near the outer ring of the pole lug is small, and the width of the pole lug near the inner ring of the pole piece is small, while the width of the pole lug near the outer ring of the pole piece is large. In this way, the flow area of ​​the electrode assembly near the outer ring of the pole piece and the flow area near the inner ring of the pole piece are not much different, which is conducive to better charging and discharging of the battery cell; and, when the flow area of ​​the electrode assembly near the outer ring of the pole piece and the flow area of ​​the pole lug group near the inner ring of the pole piece are the same, the pole lugs in the pole lug group near the inner ring will not be designed to be too wide and cannot be bent.

[0040] In one embodiment, the distance between the connection parts of two adjacent electrode tab groups gradually increases along a first direction, where the first direction is the direction from the inner circle of the electrode piece to the outer circle of the electrode piece.

[0041] By adopting the technical solution of this embodiment, the number of tab groups closer to the inner circle of the pole piece increases, and the number of tab groups closer to the outer circle of the pole piece decreases. In this way, the difference between the flow area near the inner circle of the pole piece and the flow area near the outer circle of the pole piece is smaller, which is beneficial to improving the performance of the battery cell.

[0042] In one embodiment, the electrode assembly includes a plurality of tab groups, and the plurality of tab groups are spaced apart along the circumference of the main body.

[0043] By adopting the technical solution of this embodiment, the tab groups are dispersed, and the number of tabs in a single tab group can be set to be smaller, so as to facilitate the bending of the tab group.

[0044] In one embodiment, at least one of the welding segment and the connecting segment is provided with a hollow structure.

[0045] By adopting the technical solution of this embodiment, the design of the hollow structure can reduce the structural strength of the tab, thereby facilitating the bending of the tab.

[0046] In one embodiment, when the welding section is provided with a 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 a hollow structure; when the connecting section is provided with a hollow structure, the connecting section includes a plurality of connecting sections connected to the welding section, the plurality of connecting sections are arranged at intervals along the circumference of the main body, and the gap between two connected connecting sections forms a hollow structure.

[0047] By adopting the technical solution of this embodiment, the position of the hollow structure can be flexibly set to meet different usage requirements.

[0048] In one embodiment, when both the welding segment and the connecting segment are provided with a hollow structure, the plurality of welding segments and the plurality of connecting segments are connected in a one-to-one correspondence.

[0049] By adopting the technical solution of this embodiment, the tab is divided into a multi-section disconnected structure, the tab is easy to bend, and the tab bending process is more time-saving and labor-saving.

[0050] In one embodiment, the end of the welding 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 welding 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.

[0051] By adopting the technical solution of this embodiment, the bending direction of the tab can be flexibly set to meet different usage requirements.

[0052] In one embodiment, the welding portion is located between the main body portion and the adapter.

[0053] By adopting the technical solution of this embodiment, after the tab is bent, the adapter can be placed on the welding portion for welding, and the assembly operation is simple.

[0054] In one embodiment, the battery cell further includes a connector, and a connector is welded between the welding portion and the adapter; and / or a welding portion is welded between the connector and the adapter.

[0055] By adopting the technical solution of this embodiment and providing the connecting piece, the welding thickness can be increased, the risk of damaging the main body due to welding through can be reduced, and the welding quality of the welding part and the adapter can be improved.

[0056] In one embodiment, the thickness of the welding portion is H1, the thickness of the connecting piece is H2, the number of connecting pieces is N, and the thickness of the welding position between the adapter and the welding portion is H3, wherein,

[0057] By adopting the technical solution of this embodiment, The design makes the sum of the thickness of the welding part and all the connecting parts greater than or equal to the thickness H3 of the welding position of the adapter and the welding part, and makes the sum of the thickness of the welding part and all the connecting parts larger than the thickness of the welding position of the welding part, so that the welding part and the connecting parts are not easily penetrated by welding, which can reduce damage to the main body, improve welding quality, and improve the yield rate of battery cells.

[0058] In one embodiment, when a connecting piece is welded between the welding portion and the transition piece, a thickness H1 of the welding portion is greater than a thickness H2 of the connecting piece.

[0059] By adopting the technical solution of this embodiment, when the welding part and the adapter are welded, since the connecting part is located between the welding part and the adapter, the welding part is welded from the connecting part weld bead, and the thickness H1 of the welding part is greater than the thickness H2 of the connecting part. The welding part is not easily welded through, reducing the risk of damage to the main body, which is conducive to improving the welding quality and the yield rate of the battery cell.

[0060] In one embodiment, the thickness of the connecting member is H2, wherein 0.2 mm ≤ H2 ≤ 0.4 mm.

[0061] By adopting the technical solution of this embodiment, the thickness H2 of the connector is set within the range of 0.2 mm to 0.4 mm. The thickness H2 of the connector is reasonably set. On the one hand, it can reduce the risk of damage to the main body due to welding through the welding part; on the other hand, the connector will not take up too much space, which is conducive to improving the volume energy density of the battery cell. With this design, the thickness H2 of the connector will not be easily caused to be welded through by the connector and the welding part due to being designed too small; and the thickness H2 of the connector will not take up more space in the battery cell due to being designed too large.

[0062] In one embodiment, the adapter is located between the welding portion and the main body portion.

[0063] 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, welding is carried out from the welding part to the adapter, and the structural strength of the adapter is generally better than the structural strength of the welding part, so that the adapter is not easily welded through, thereby reducing the risk of damage to the main body, which is beneficial to improving the welding quality and the yield rate of the battery cell.

[0064] In one embodiment, the adapter is provided with a through hole, and the connecting portion is passed through the through hole.

[0065] By adopting the technical solution of this embodiment, after the tab group passes through the through hole and is bent, the welding portion is located on the side of the adapter facing away from the main body. The through hole provides a through space for the tab group, which has a simple structure and is easy to process and manufacture.

[0066] In one embodiment, when the end of the welding portion facing away from the connecting portion is located on a side of the connecting portion close to the inner ring of the tab, the connecting portion is located on a side of the adapter close to the outer ring of the pole piece.

[0067] By adopting the technical solution of this embodiment, the tab group directly passes through the side of the adapter close to the outer ring of the pole piece and then is bent, so that the welding part can be located on the side of the adapter facing away from the main body. There is no need to set a penetrating structure on the adapter, which facilitates processing and manufacturing.

[0068] In one embodiment, a notch is provided on one side of the adapter close to the outer ring of the pole piece, and the connecting portion is located in the notch.

[0069] By adopting the technical solution of this embodiment, the notch can provide installation space for the connecting part, so that the connecting part is not easy to protrude outside the outer wall of the main body. A certain distance can be maintained between the connecting part and the cavity wall of the installation cavity, reducing the risk of extrusion between the connecting part and the outer shell, which is beneficial to improving the reliability of the battery cell. The overall structure is compact, which is beneficial to improving the energy density of the battery cell.

[0070] In one embodiment, the battery cell includes a plurality of tab groups, the welding portions of some tab groups are located between the main body and the adapter; the welding portions of another portion of the tab groups are located on a side of the adapter facing away from the main body.

[0071] By adopting the technical solution of this embodiment, the tabs of the electrode assembly are divided into multiple tab groups, so that the number of tabs in each tab group can be designed to be smaller to facilitate bending; in addition, the position of the welding part of the tab group can also be flexibly set, making assembly simpler and more convenient.

[0072] In one embodiment, the adapter includes a flipping portion and a fixed portion that are connected to each other, the flipping portion is welded to the welding portion, and the flipping portion can be flipped relative to the fixed portion.

[0073] By adopting the design of this embodiment, the welding direction of the welding laser can be changed, thereby reducing the risk of the welding laser penetrating the weld portion and not striking the main body and damaging the main body, thereby improving the performance of the battery cell. In a second aspect, a battery cell manufacturing method is provided for manufacturing the battery cell of the above embodiment, the battery cell manufacturing method comprising the following steps:

[0074] The tab group of the electrode assembly is bent toward the end of the main body of the electrode assembly, wherein the main body is a cylindrical structure formed by winding the pole piece, and at least two turns of the pole piece lead out the pole tab from the end surface of the main body, and the pole piece leads out multiple pole tabs arranged radially along the main body to form a pole tab group; the pole tabs in the pole tab group are bent to form welding sections and connecting sections, and the welding sections of the multiple pole tabs are stacked along the axial direction of the main body to form a welding portion, and the connecting sections of the multiple pole tabs are stacked along the radial direction of the main body to form a connecting portion;

[0075] The adapter is welded to the welding portion, and the adapter and the welding portion are stacked along the axial direction of the main body;

[0076] The welded adapter and electrode assembly are installed into the mounting cavity of the housing.

[0077] The battery cell manufacturing method of the embodiment of the present application is to first bend the tab group to form a welding portion and a connecting portion, then weld the welding portion and the adapter together, and finally install the welded electrode assembly and the adapter into the installation cavity of the shell; and in this process, the welding portion formed after the tab group is bent, and the welding sections in the welding portion can be flatly and tightly fitted together to form a tight welding portion, thereby reducing the problem of poor welding between the welding portion and the adapter, which is beneficial to improving the performance of the battery cell.

[0078] In one embodiment, before the tab assembly is bent, the tab assembly is folded along the stacking direction of the welding segments.

[0079] By adopting the technical solution of this embodiment, the extrusion and contraction can make the bent welding sections fit together more tightly to form a tighter welding part, reducing the risk of welding defects such as cold welding and weld penetration, and is more conducive to improving the welding quality of the adapter and the tab.

[0080] In one embodiment, after the tabs are folded and before the tabs are bent, the tab group is pre-welded so that the tabs in the tab group are welded together.

[0081] By adopting the technical solution of this embodiment, the tabs in the tab group are welded together by pre-welding after the tabs are folded and before the tabs are bent. This can reduce the risk of the tabs becoming loose after subsequent bending, so that the welding sections in the subsequent welding part can fit together to form a tight welding part, thereby reducing the risk of poor welding such as cold welding and weld-through, which is beneficial to improving the welding quality of the welding part and the adapter.

[0082] In one embodiment, the end portion of the tab group facing away from the main body is pre-welded.

[0083] 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 is completed, the end of the tab assembly close to the main body is in a free state to facilitate bending of the tab assembly.

[0084] In a third aspect, a battery is provided, comprising the battery cell according to the above embodiment, and / or comprising a method for manufacturing the battery cell according to the above embodiment to obtain the battery cell.

[0085] In a third aspect, an electrical device is provided, comprising a battery according to the above embodiment.

[0086] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only one embodiment of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0088] FIG1 is a schematic structural diagram of a vehicle provided in one embodiment of the present application.

[0089] FIG2 is a schematic structural diagram of a battery provided in an embodiment of the present application.

[0090] FIG3 is a cross-sectional view of a battery cell provided in one embodiment of the present application.

[0091] FIG4 is an exploded schematic diagram of a battery cell provided in one embodiment of the present application.

[0092] FIG5 is a schematic structural diagram of the battery cell shown in FIG4 .

[0093] FIG6 is a cross-sectional view taken along line AA in FIG5 .

[0094] FIG7 is a partial enlarged view of point B in FIG6 .

[0095] FIG8 is a partial enlarged view of point C in FIG7 .

[0096] FIG9 is a simplified diagram of a battery cell manufacturing process according to an embodiment of the present application.

[0097] FIG10 is a partial enlarged view of point D in FIG9 .

[0098] FIG11 is a structural schematic diagram of an electrode assembly of a battery cell provided in another embodiment of the present application from one perspective.

[0099] FIG12 is a schematic structural diagram of the electrode assembly shown in FIG11 from another perspective.

[0100] FIG13 is a structural schematic diagram of an electrode assembly of a battery cell provided in another embodiment of the present application from one perspective.

[0101] FIG14 is a schematic structural diagram of the electrode assembly shown in FIG13 from another perspective.

[0102] FIG15 is a schematic structural diagram of an electrode assembly of a battery cell provided in yet another embodiment of the present application.

[0103] FIG16 is a partially enlarged view of a cross section of a battery cell provided in another embodiment of the present application.

[0104] FIG17 is a cross-sectional view of a battery cell provided in yet another embodiment of the present application.

[0105] FIG18 is a partial enlarged view of point E in FIG17 .

[0106] FIG19 is a cross-sectional view of a battery cell provided in yet another embodiment of the present application.

[0107] FIG20 is a partial enlarged view of point F in FIG19 .

[0108] FIG21 is a schematic structural diagram of the end cover and adapter of the battery cell shown in FIG17 .

[0109] FIG22 is a partially enlarged view of a cross section of a battery cell provided in yet another embodiment of the present application.

[0110] FIG23 is a partially enlarged view of a cross section of a battery cell provided in yet another embodiment of the present application.

[0111] FIG24 is a partially enlarged view of a cross section of a battery cell provided in yet another embodiment of the present application.

[0112] FIG25 is a schematic structural diagram of an end cover and an adapter of a battery cell provided in yet another embodiment of the present application.

[0113] In the figures, the reference numerals are as follows: 1000, vehicle; 1100, battery; 1200, controller; 1300, motor; 10, housing; 20, battery cell; 210, housing; 211. Shell; 212. End cover; 2121. Electrode terminal; 2111. Mounting cavity; 220. Electrode assembly; 221. Main body; 222. Tab group; 2221. Welding portion; 2222. Connecting portion; 2223. Spacing gap; 223. Pole piece; 2231. First pole piece; 2232. Second pole piece; 224. Tab; 2241. Welding section; 2242. Welding section; 2243. Connecting section; 2244. Connecting section; 2245. Hollow structure; 225. Pre-welded structure; 226. Diaphragm; 230. Adapter; 231. Through hole; 232. Notch; 233. Turning portion; 234. Fixing portion; 235. Connecting structure; 240. Connector; 250. Binding layer. DETAILED DESCRIPTION

[0114] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0115] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0116] In the description of the embodiments of this application, the technical terms "first," "second," etc., are used solely to distinguish between different objects and should not be understood to indicate or imply relative importance, or to implicitly specify the quantity, specific order, or primary-secondary relationship of the technical features indicated. Therefore, a feature designated "first" or "second" may explicitly or implicitly include one or more of such features.

[0117] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments in any suitable manner.

[0118] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0119] In the description of the embodiments of this application, the term "plurality" refers to two or more (including two). Similarly, "multiple groups" refers to two or more (including two groups), and "multiple sheets" refers to two or more (including two sheets). "Several" means one or more, unless otherwise specifically defined.

[0120] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the embodiments of the present application.

[0121] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0122] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, when an element is referred to as being “fixed to” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0123] 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 a crucial component of the industry's sustainable development. Battery technology, in turn, is a crucial factor in the development of electric vehicles.

[0124] A battery cell is the smallest unit that makes up a battery. An electrode assembly is arranged in the outer shell of the battery cell. The electrode assembly is a cylindrical structure formed by winding a stacked positive electrode sheet, a negative electrode sheet, and a separator. The electrode assembly mainly relies on the movement of active ions (for example, lithium ions) between the positive electrode sheet and the negative electrode sheet for charging and discharging. The positive electrode sheet includes a positive electrode collector and a plurality of positive electrode tabs extending from the edge of the positive electrode collector. The positive electrode collector and the positive electrode tabs can be obtained by die-cutting, or by welding a conductor to the edge of the positive electrode collector to obtain the positive electrode tabs. The positive electrode collector is usually covered with a positive electrode active material, and the positive electrode tabs are not covered with a positive electrode active material. Taking lithium-ion batteries as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode sheet includes a negative electrode current collector and a plurality of negative electrode ears extending from the edge of the negative electrode current collector, wherein the negative electrode current collector and the negative electrode ears can be obtained by die-cutting, or the negative electrode ears can be obtained by welding a conductor to the edge of the negative electrode current collector; the negative electrode current collector is usually covered with a negative electrode active material, and the negative electrode ears are not covered with a negative electrode active material; the material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon, etc. The material of the diaphragm can be polypropylene (PP for short) or polyethylene (PE for short), etc. The diaphragm is an insulating film arranged between the positive electrode sheet and the negative electrode sheet. Its main function is to isolate the positive and negative electrodes and prevent the electrons in the battery from passing freely to prevent short circuits, while allowing the ions in the electrolyte to pass freely between the positive and negative electrodes to form a circuit between the positive and negative electrodes.

[0125] During battery cell manufacturing, in some cases, the cells are stacked in the order of positive electrode sheet, separator, negative electrode sheet, and separator, and then wound. After winding, the positive current collector, negative current collector, and separator form the main portion of the electrode assembly, known as the main body. The positive tabs extend axially from the main body and protrude beyond the end of the main body, and multiple positive tabs are stacked radially along the electrode assembly to form a positive tab group. The negative tabs extend axially from the main body and protrude beyond the end of the main body, and multiple negative tabs are stacked radially along the electrode assembly to form a negative tab group. The outer casing is typically provided with electrode terminals and adapters. After welding the adapters to the positive and negative tab groups, the adapters are then connected to the electrode terminals, enabling current input and output through the electrode terminals. It is understood that the adapters include a positive adapter and a negative adapter, and the electrode terminals include a positive electrode terminal and a negative electrode terminal. The positive adapter connects the positive tab group to the positive electrode terminal, and the negative adapter connects the negative electrode terminal to the negative tab group. For the convenience of description, the positive electrode sheet and the negative electrode sheet can be collectively referred to as the electrode sheet, the positive electrode tab and the negative electrode tab can be collectively referred to as the electrode tab, the positive adapter and the negative adapter can be collectively referred to as the adapter, and the positive electrode terminal and the negative electrode terminal can be collectively referred to as the electrode terminal.

[0126] During the manufacturing process of battery cells, the tabs are usually curved after winding, and the curved tabs are flattened before being welded to the adapter. However, the flattened tabs are prone to wrinkles and the roots of the tabs near the outer ring are prone to expansion, and gaps are prone to appear between the tabs or the tabs are not tightly fitted. In other words, the tabs are not dense enough when flattened, which leads to poor welding problems such as cold welding and weld penetration when welding the adapter to the tabs, affecting the performance of the battery cell.

[0127] In order to improve the problem of poor welding between the adapter and the tab, an embodiment of the present application provides a battery cell. After the pole sheet is wound, the tab group led out from the end of the main body is bent toward the end of the main body, and the tabs in the tab group are bent to 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 portion, and the connecting sections of multiple tabs are stacked along the radial direction of the main body to form a connecting portion. The welding portion and the adapter are then stacked and welded together, and finally installed into the mounting cavity of the shell, thus completing the production of the battery cell. In this process, after the tab group is bent, the welding sections of multiple tabs in the tab group can be stacked together flatly to form a tight welding portion, thereby reducing the problem of poor welding between the welding portion and the adapter, which is beneficial to improving the performance of the battery cell.

[0128] The battery cells, batteries, and electrical devices using the batteries as power sources disclosed in the embodiments of the present application may include, but are not limited to, mobile phones, tablets, laptop computers, electric toys, power tools, battery-powered vehicles, electric vehicles, ships, spacecraft, and the like. Electric toys may include fixed or mobile electric toys, such as game consoles, electric vehicle toys, electric ship toys, and electric airplane toys, and spacecraft may include airplanes, rockets, space shuttles, and spacecraft, among others.

[0129] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0130] Please refer to Figure 1, which is a schematic structural diagram of a vehicle 1000 provided in an embodiment of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 1100 is provided inside the vehicle 1000, and the battery 1100 can be provided at the bottom, head or tail of the vehicle 1000. The battery 1100 can be used to power the vehicle 1000. For example, the battery 1100 can serve as an operating power source for the vehicle 1000. The vehicle 1000 can also include a controller 1200 and a motor 1300. The controller 1200 is used to control the battery 1100 to power the motor 1300, for example, for starting, navigating and driving the vehicle 1000.

[0131] In one embodiment of the present application, the battery 1100 can not only serve as the operating power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0132] Referring to Figure 2, as an embodiment of a battery 1100, the battery 1100 includes a housing 10 and a battery cell 20, with the battery cell 20 being housed within the housing 10. The housing 10 is used to provide a storage space for the battery cell 20, and the housing 10 can have a variety of structures. In one embodiment, the housing 10 can include a first portion and a second portion, the first portion and the second portion overlapping each other, and the first portion and the second portion together define a storage space for accommodating the battery cell 20. The second portion can be a hollow structure with one end open, and the first portion can be a plate-like structure, with the first portion overlapping the open side of the second portion, so that the first portion and the second portion together define a storage space; the first portion and the second portion can also be hollow structures with one end open, with the open side of the first portion overlapping the open side of the second portion. Of course, the housing 10 formed by the first portion and the second portion can have a variety of shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0133] In the battery 1100 , there may be multiple battery cells 20 , and the multiple battery cells 20 may be connected in series, in parallel, or in mixed connection. Mixed connection means that the multiple battery cells 20 are connected in both series and in parallel.

[0134] In one embodiment, multiple battery cells 20 may be directly connected in series, parallel, or hybrid, and the entire battery cell 20 may then be housed within the housing 10. Alternatively, the battery 1100 may be constructed by first connecting multiple battery cells 20 in series, parallel, or hybrid to form a battery module, which is then connected in series, parallel, or hybrid to form a complete battery module, and then housed within the housing 10. The battery 1100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0135] Each battery cell 20 may be a secondary battery or a primary battery, and may also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0136] As another embodiment of the battery 1100 , the battery 1100 may not include the housing 10 , but may be assembled into an electrical device by electrically connecting a plurality of battery cells 20 and forming a whole with necessary fixing structures.

[0137] Please refer to Figures 3 and 4. Figure 3 is a cross-sectional view of a battery cell 20 provided in an embodiment of the present application, and Figure 4 is a schematic diagram of the exploded structure of a battery cell 20 provided in an embodiment of the present application. The battery cell 20 refers to the smallest unit that makes up the battery. As shown in Figure 3, the battery cell 20 includes a shell 210, an electrode assembly 220, a restraining layer 250, and other functional components. The shell 210 refers to a component used to isolate the internal environment of the battery cell 20 from the external environment, and the shell 210 is surrounded to form an installation cavity 2111, which is used to provide installation space for components such as the electrode assembly 220 and the restraining layer 250; for example, as shown in Figure 4, the shell 210 includes a shell 211 and an end cover 212.

[0138] The end cap 212 refers to a component that covers the opening of the shell 211 and is together with the shell 211 to form a mounting cavity 2111 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 212 can be adapted to the shape of the shell 211 to match the shell 211. In one embodiment, the end cap 212 can be made of a material with a certain hardness and strength (such as aluminum alloy). In this way, the end cap 212 is not easily deformed when squeezed or collided, so that the battery cell 20 can have a higher structural strength and improved safety performance. Functional components such as electrode terminals 2121 and adapters 230 can be provided on the end cap 212. The adapter 230 is located in the mounting cavity 2111 and is used to electrically connect the electrode terminals 2121 and the electrode assembly 220. The electrode terminals 2121 are exposed from the outside of the end cap 212 and are used to electrically connect to external electrical equipment for outputting or inputting electrical energy from the 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 may also be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment of the present application does not impose any particular restrictions on this. In one embodiment, an insulating member may also be provided on the inner side of the end cap 212. The insulating member may be used to isolate the electrical connection components in the housing 211 from the end cap 212 to reduce the risk of short circuits. Exemplary, the insulating member may be plastic, rubber, etc.

[0139] The shell 211 is a component used to cooperate with the end cap 212 to form the internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 220, electrolyte and other components. The shell 211 and the end cap 212 can be independent components. An opening can be set on the shell 211, and the internal environment of the battery cell 20 is formed by covering the opening with the end cap 212. Without limitation, the end cap 212 and the shell 211 can also be integrated. Specifically, the end cap 212 and the shell 211 can form a common connection surface before other components are inserted into the shell. When the interior of the shell 211 needs to be encapsulated, the end cap 212 is covered with the shell 211. The shell 211 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the shell 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., and the embodiment of the present application does not impose any special restrictions on this.

[0140] The electrode assembly 220 is a component in the battery cell 20 where electrochemical reactions occur. One or more electrode assemblies 220 may be contained in the housing 211. The electrode assembly 220 includes a first electrode sheet 2231, a second electrode sheet 2232, and a diaphragm 226. The polarity of the first electrode sheet 2231 and the second electrode sheet 2232 is different, that is, one of the first electrode sheet 2231 and the second electrode sheet 2232 is a positive electrode sheet and the other is a negative electrode sheet. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and extracted back and forth between the positive electrode sheet and the negative electrode sheet. The diaphragm 226 is arranged between the positive electrode sheet and the negative electrode sheet, which can prevent the positive and negative electrodes from short-circuiting, while allowing active ions to pass through. The electrode assembly 220 is stacked and wound in the order of positive electrode sheet, separator 226, negative electrode sheet, and separator 226 to form a cylindrical electrochemical structure. After the electrode assembly 220 is wound, a tie layer 250 is applied to tightly wind the positive electrode sheet, negative electrode sheet, and separator 226 together. The tie layer 250 includes, but is not limited to, an insulating film, such as a blue film.

[0141] 4 to 12, the embodiment of the present application provides a battery cell 20, including a shell 210, an adapter 230 and an electrode assembly 220, the shell 210 has a mounting cavity 2111; the electrode assembly 220 is located in the mounting cavity 2111, 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 a pole piece 223, at least two turns of the pole piece 223 lead out a tab 224 from the end face of the main body 221, the pole piece 223 leads out a plurality of tabs 224 arranged radially along the main body 221 to form a tab group 222; the tab group 222 is bent toward the end of the main body 221, and the tab group 222 is bent toward the end of the main body 221. The tabs 224 in the tab group 222 are 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 curved. The welding sections 2241 of the multiple tabs 224 in the tab group 222 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 in the tab group 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.

[0142] 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 part of a cylindrical structure formed by winding the positive electrode collector, the negative electrode collector and the separator 226, wherein the electrode 223 in the following embodiments may refer to a positive electrode sheet or a negative electrode sheet.

[0143] The pole ear 224 may refer to a conductive component extending from the end surface of the main body 221; specifically, the pole ear 224 may also refer to a portion extending from the edge of the current collector of the pole piece 223 and not coated with an active material; it can be understood that, in conjunction with Figures 3, 11, and 12, before the pole piece 223 is wound, the pole piece 223 and the diaphragm 226 are flatly stacked, and the pole piece 223 is provided with a plurality of pole ears 224. Multiple pole tabs 224 are distributed in sequence along the length direction of the current collector; after the pole piece 223 is wound circle by circle, at least some of the circles in the pole piece 223 have pole tabs 224, that is, at least two circles in the pole piece 223 have pole tabs 224 led out from the end of the main body 221; and at least some of the pole tabs 224 of the same polarity are gathered at one place and stacked along the radial direction of the main body 221 to form a pole tab group 222, that is, the pole tab group 222 refers to a combination formed by stacking multiple pole tabs 224 of the same polarity along the radial direction of the main body 221; in addition, as the pole piece 223 is wound, the pole tabs 224 are also bent into a bent shape. Among them, the number of tab groups 222 can be multiple, which is specifically 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, wherein the tab 224 in the positive tab group 222 is a positive tab, the tab 224 in the negative tab group 222 is a negative tab, the tab 224 led out of the positive electrode sheet is a positive tab, and the tab 224 led out of the negative electrode sheet is a negative tab.

[0144] Please refer to Figures 9 and 10 together. In the actual manufacturing process, before the tab group 222 is bent, the tab group 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, thereby reducing the height of the electrode assembly 220 and facilitating stacking and welding with the adapter 230.

[0145] The tab 224 in the tab group 222 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 curved. It can be understood that after the tab 224 is bent, the tab 224 is divided into two parts by the bending part of the tab 224 (see the dotted line in Figure 11). The part close to the main body 221 is the connecting section 2243, and the part away from the main body 221 is the welding section 2241. For example, please refer to Figure 13, where the dotted line on the tab group 222 in Figure 13 represents the bending part of the tab group 222, and the tab group 222 is bent along the dotted line. Bending, the dotted line divides the tab group 222 into two parts, wherein 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, wherein the part of the tab 224 located in the welding part 2221 is the welding section 2241, and the part of the tab 224 located in the connecting part 2222 is the connecting section 2243, and after the tab group 222 is bent toward the end face of the main body 221, the connecting sections 2243 of the multiple tabs 224 in the tab group 222 are stacked along the radial direction of the main body 221, and the welding sections 2241 of the multiple tabs 224 in the tab group 222 are stacked along the axial direction of the main body 221. The radial direction of the main body 221 can refer to the X direction in the figure, the axial direction of the main body 221 can refer to the Z direction in the figure, the axis of the main body 221 can refer to the AA line in the figure, and the circumferential direction of the main body 221 can refer to the direction indicated by the double-headed arrow M in the figure.

[0146] The connecting section 2243 is curved. It can be understood that, in combination with Figures 11 and 12, after the pole piece 223 is wound, the pole ear 224 is led out along the axial direction of the main body 221 and is in an arc shape; after the pole ear 224 is retracted and bent, the welding section 2241 may be squeezed into a plane, or it may maintain a certain curvature; and the part close to the connecting section 2243 may be straight, and the part close to the main body 221 will always have a certain curvature, or it may maintain a certain curvature as a whole; but the connecting section 2243 will always present a certain arc and be curved due to the influence of the winding of the pole piece 223.

[0147] The adapter 230 may be a component that is welded to the tab 224 of the electrode assembly 220. The adapter 230 is electrically conductive and is used to output or input electrical energy from the electrode assembly 220. In one embodiment, as shown in FIG7 , the adapter 230 may be mounted on the end cap 212. For example, the end cap 212 may be provided with an electrode terminal 2121, and the adapter 230 may be disposed on the inner side of the end cap 212. The adapter 230 is connected to the electrode terminal 2121 to output or input electrical energy from the battery cell 20 through the electrode terminal 2121. The adapter 230 may be integrally connected to the electrode terminal 2121 or separately connected to the electrode terminal 2121. For example, the adapter 230 may be connected to the electrode terminal 2121 by welding, clamping, threading, or other methods. In other embodiments, the adapter 230 may also be mounted on the housing 211, for example, on the wall of the housing 211 that interfaces with the end cap 212. The adapter 230 can be made of a conductive material with a certain hardness and strength, such as copper, aluminum, etc. It should be noted that when the adapter 230 is connected to the electrode terminal 2121, the material of the adapter 230 can be the same as or different from the material of the electrode terminal 2121. The welding portion 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 portion 2221 along the axial direction of the main body 221. In this way, the adapter 230 can be welded to at least most of the welding segments 2241 in the welding portion 2221, so that there is good welding strength between the welding portion 2221 and the adapter 230, which is beneficial to improving the reliability of the electrical connection between the welding portion 2221 and the adapter 230.

[0148] In the battery cell 20 of the embodiment of the present application, after the electrode assembly 220 is wound, the end of the main body 221 of the electrode assembly 220 is led out to the tab group 222 and bent, and the tabs 224 in the tab group 222 are bent to form a welding section 2241 and a connecting section 2243; and 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 section 2221, and the connecting sections 222 of the multiple tabs 224 in the tab group 222 are stacked along the axial direction of the main body to form a welding section 2221. The connecting segments 2243 are stacked along the radial direction of the main body, and then the adapter 230 is welded to the welding portion 2221, thereby 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 the multiple tabs 224 in the tab group 222 can be stacked together flatly to form a tight welding portion 2221, thereby reducing the problem of poor welding between the welding portion 2221 and the adapter 230, which is beneficial to improving the performance of the battery cell 20.

[0149] In another embodiment, as shown in FIG11 and FIG12 , the length of the connecting section 2243 is L1, and the radius of a circle corresponding to the connection between the pole piece 223 and the connecting section 2243 is R, wherein the radius of a circle corresponding to the connection between the pole piece 223 and the connecting section 2243 is R, wherein,

[0150] The length of the connecting segment 2243 may refer to the arc length L1 of the connecting segment 2243 before the tab 224 is folded and bent.

[0151] The circle in which the pole piece 223 is connected to the connecting section 2243 may refer to a circle in which the pole piece 223 is connected to the connecting section 2243, wherein after the pole piece 223 is wound, the pole piece 223 forms a circle that is close to a circle; in actual measurement, the circle in which the pole piece 223 is connected to the connecting section 2243 may refer to a circle in which the pole piece 223 is connected to the connecting section 2243, which is wound around the axis of the main body 221 with one side of the connecting section 2243 as the starting point and toward the other side of the connecting section 2243, and half of the radial size of the circle in the main body 221 is taken as R.

[0152] By adopting the technical solution of this embodiment, the curvature of the pole ear 224 corresponding to the circles of different radii in the pole piece 223 can be controlled not to be too large, thereby facilitating the folding and bending of the pole ear 224. In addition, the folding and bending of the pole ear 224 generate little pulling force on the main body 221, reducing the risks of cracking of the pole ear 224 and falling off of the active material, which is beneficial to improving the yield and performance of the battery cell 20.

[0153] In another embodiment of the present application, as shown in FIG11 and FIG12 ,

[0154] By adopting the technical solution of this embodiment, the curvature of the pole ear 224 drawn by the circles corresponding to different radii of the pole piece 223 is smaller, making the folding and bending of the pole ear 224 simpler and more labor-saving, and the pulling force generated by the folding and bending of the pole ear 224 on the main body 221 is smaller, which can effectively reduce the risks of cracking of the pole ear 224 and falling off of the active material, and effectively improve the yield and performance of the battery cell 20.

[0155] In one embodiment, The value of 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.

[0156] In another embodiment of the present application, as shown in combination with FIG. 11 and FIG. 12 , the length L1 of the connecting segment 2243 in at least one tab 224 is smaller than the length L7 of the welding segment 2241 .

[0157] The length L7 of the welding section 2241 may refer to the arc length of the welding section 2241 before the tab 224 is bent. The connecting section 2243 and the welding section 2241 are both located within the same tab, meaning that the length of the connecting section 2243 and the length of the welding section 2241 within the same tab are different, and the length of the connecting section 2243 is less than the length of the welding section 2241. As shown in FIG11 and FIG12 , the tab 224 has notches formed at opposite ends of the connecting section 2243, thereby making the length L1 of the connecting section 2243 less than the length L7 of the welding section 2241. The opposite ends of the tab 224 at the connecting section 2243 refer to the opposite ends of the connecting section 2243 along the circumference of the main body 221. In addition, 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 than four; or all tabs 224 in the tab group 222 can adopt a structural form in which the length of the connecting section 2243 is less than the length of the welding section 2241.

[0158] By adopting the technical solution of this embodiment, the connecting section 2243 is shorter than the welding section 2241 , and the folding and bending of the tab 224 is simpler and faster, which is beneficial to the folding and bending of the tab 224 .

[0159] In another embodiment, as shown in combination with FIG. 9 and FIG. 10 , the tab group 222 is provided with a pre-welding structure 225 , and the pre-welding structure 225 is used to connect the plurality of tabs 224 in the tab group 222 .

[0160] The pre-welded structure 225 may refer to a welded structure formed by welding together the multiple tabs 224 in the tab group 222 before the welding portion 2221 is welded to the adapter 230. For example, the pre-welded structure 225 may refer to a weld seam, weld mark, or other structure that welds together the multiple tabs 224 in the tab group 222. 25 , the tab group 222 and the welding portion 2221 are welded to form a connecting structure 235, and the pre-welding structure 225 and the connecting structure 235 are staggered so that the two weldings of the tab group 222 are not at the same place, which is beneficial to improving the welding quality and the performance of the battery cell 20, wherein the pre-welding structure 225 can be arranged at the side edge of the tab group 222, and the connecting structure 235 is arranged in the middle of the welding portion 2221; the pre-welding structure 225 and the connecting structure 235 can also be arranged on the surface of the welding portion 2221 facing the adapter 230 and staggered, wherein the connecting structure 235 can refer to structures such as welds, weld marks, etc. that weld the welding portion 2221 and the adapter 230 together.

[0161] By adopting the technical solution of this embodiment, the multiple tabs 224 in the tab group 222 are pre-welded together to form a whole before the tab group 222 is bent, thereby reducing the risk of the tab group 222 becoming loose. In addition, after the tab group 222 is bent, the multiple tabs 224 in the tab group 222 will fit together more closely to form a tighter welding portion 2221, which is beneficial to improving the welding quality of the tab 224 and the adapter 230, and is beneficial to improving the performance of the battery cell 20.

[0162] In another embodiment of the present application, as shown in combination with FIG. 9 and FIG. 10 , a pre-welding structure 225 is provided at the welding portion 2221 .

[0163] By adopting the technical solution of this embodiment, the pre-welding structure 225 can weld together multiple welding segments 2241 in the tab group 222, so that after the tab group 222 is bent, the welding portion 2221 is not easy to fall apart, and a tight welding portion 2221 can be formed after the tab 224 is bent, so that the welding quality between the tab 224 and the adapter 230 is better, and the performance of the battery cell 20 is better; in addition, the pre-welding structure 225 will not be welded to the connecting segment 2243, so that when the tab group 222 is bent, the connecting segments 2243 can move relative to each other to facilitate the bending of the tab 224.

[0164] In another embodiment of the present application, as shown in Figures 5 to 7, the distance between the pre-welding structure 225 and the connecting portion 2222 is L2, where 0.1 mm ≤ L2 ≤ 10 mm.

[0165] By adopting the technical solution of this embodiment, the spacing between the pre-welding structure 225 and the connecting section 2243 is within the above-mentioned range, and there is a certain distance between the bending part of the tab group 222 and the main body 221. In this way, when the tab group 222 is bent, the connection between the main body 221 and the tab 224 and the pre-welding structure 225 will not be excessively pulled. On the one hand, the tab group 222 can be bent more smoothly, reducing the risks of cracking of the tab 224 and falling off of the active material, which is beneficial to improving the yield and performance of the battery cell 20; on the other hand, the pre-welding structure 225 can stably weld together multiple welding sections 2241 in the tab group 222, so that the welding part 2221 is not easy to fall apart, and a tight welding part 2221 can be formed after the tab 224 is bent, so that the welding quality between the tab 224 and the adapter 230 is better, and the performance of the battery cell 20 is better.

[0166] In another embodiment of the present application, as shown in Figures 5 to 7, 0.5 mm ≤ L2 ≤ 10 mm.

[0167] By adopting the technical solution of this embodiment, the distance between the pre-welded structure 225 and the connecting section 2243 is more reasonably designed, and the risk of bending the tab 224 and pulling the connection between the tab 224 and the main body 221 is reduced, so that the tab group 222 can be bent more smoothly.

[0168] 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.

[0169] In another embodiment of the present application, as shown in combination with FIG. 9 and FIG. 10 , the pre-welding structure 225 is located at the end of the welding portion 2221 facing away from the connecting section 2243 .

[0170] Through the technical solution of this embodiment, before the tab group 222 is bent, the ends of the welding sections 2241 in the tab group 222 away from the connecting sections 2243 are welded together, and the welding operation is simple, convenient and fast. 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 group 222 more time-saving and labor-saving.

[0171] In another embodiment, the pre-welding structure 225 may also be disposed on the side where the welding portion 2221 and the connecting portion 2222 are connected.

[0172] In another embodiment of the present application, as shown in FIG9 and FIG10 , the length of the welding portion 2221 is L3, and the length of the pre-welding structure 225 in the length direction of the welding portion 2221 is L4, wherein,

[0173] The length L3 of the welding portion 2221 may refer to the length dimension of the welding portion 2221 in the length direction (Y direction) of the welding segment 2241 .

[0174] The length L4 of the pre-welding structure 225 may refer to the length dimension of the pre-welding structure 225 in the longitudinal direction of the welding portion 2221 .

[0175] By adopting the technical solution of this embodiment, the ratio between the length L4 of the pre-welding structure 225 and the length L3 of the welding portion 2221 is within the above range, so that the pre-welding structure 225 can reliably weld together the multiple welding segments 2241 in the tab group 222, reducing the risk of the welding portion 2221 becoming loose, and also reducing the risk of pre-welding the tab 224 and causing damage to other components.

[0176] In one embodiment, The value of 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.

[0177] In another embodiment of the present application, as shown in FIG11 and FIG12 , the total number of turns of the pole piece 223 is N1, and the total number of turns of the pole piece 223 connected to the pole lug 224 is N2, wherein,

[0178] The total number of turns of the electrode piece 223 may refer to the number of winding turns of the electrode piece 223 in the electrode assembly 220 .

[0179] The total number of turns of the electrode tabs 224 connected to the electrode piece 223 may refer to the sum of the turns of the electrode tabs 224 drawn out from the electrode piece 223 of the electrode assembly 220 .

[0180] By adopting the technical solution of this embodiment, the ratio of the total number of turns of the pole tabs 224 led out of the pole piece 223 to the total number of turns of the pole piece 223 is within the above-mentioned range, so that the number of pole tabs 224 that can be led out of the electrode assembly 220 is within a reasonable range, which is beneficial to reducing the internal resistance of the electrode assembly 220 during charging and discharging and is also beneficial to the rapid charging and discharging of the battery cell 20; at the same time, the number of pole tabs 224 in the pole tab group 222 led out of the electrode assembly 220 is reasonable, and the pole tab group 222 is also easy to bend.

[0181] In another embodiment of the present application,

[0182] By adopting the technical solution of this embodiment, the ratio of the total number of turns of the tabs 224 extending from the pole piece 223 to the total number of turns of the pole piece 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 the bending of the tab group 222.

[0183] In one embodiment, The value of 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.

[0184] In another embodiment of the present application, as shown in Figures 13 and 14, the end surfaces of the main body 221 of the pole piece 223 extend the pole tabs 224 at intervals to form a plurality of pole tab groups 222, and the plurality of pole tab groups 222 are arranged at intervals along the radial direction of the main body 221.

[0185] It can be understood that, in the radial direction of the main body 221, the pole piece 223 adopts the method of spacing out (jumping circle out) the pole ear 224 to form a plurality of pole ear groups 222, and only part of the pole piece 223 leads to the pole ear 224, and the pole piece 223 does not lead to the pole ear 224. The ring is the spacing ring, and the spacing ring does not lead to the pole ear 224, so that the pole ear 224 led out of the pole piece 223 has a spacing gap 2223. Through the partition of the spacing gap 2223, Thus, the tabs 224 led out of the electrode piece 223 are divided into multiple groups, i.e., multiple tab groups 222 are formed; a gap 2223 is formed between the connecting portions 2222 of two adjacent tab groups 222, and the ring in the electrode piece 223 corresponding to the gap 2223 is a spacer ring, and the tab 224 is not led out at the position corresponding to the gap 2223, while the tab 224 may be led out at other positions of the spacer ring, or may not be led out; before the tab group 222 is bent, the gap 2223 is formed between the connecting portions 2222 of the adjacent tab groups 222, and the gap 2223 is formed between the connecting portions 2222 of the electrode piece 223 The spacing gap 2223 may refer to the gap formed between two adjacent tab groups 222. After the tab groups 222 are bent, the spacing gap 2223 refers to the gap formed between the connecting portions 2222 of the two adjacent tab groups 222. The spacing ring may refer to the ring in the electrode 223 that is opposite to the spacing gap 2223 and does not lead to the tab 224 at the spacing gap 2223. That is, the ring in the electrode 223 that does not lead to the tab 224 inserted in the spacing gap 2223 is a spacing ring. The number of spacing rings between two adjacent tab groups 222 can be one, two, three, or more than four, which can be determined according to the method of separating the tabs 224 from the electrode 223.

[0186] The plurality of tab groups 222 can be understood as comprising a plurality of tab groups 222 , for example, the number of tab groups 222 is two, three, four or more than four.

[0187] The connecting portions 2222 of the multiple tab groups 222 are arranged at radial intervals along the main body 221. It can be understood that before the tab groups 222 are bent, the multiple tab groups 222 are arranged at radial intervals along the main body 221. After the tab groups 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 in the multiple tab groups 222 are stacked along the axial direction of the main body 221 to facilitate welding with the adapter 230; and 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 groups 222 are arranged at radial intervals along the main body 221.

[0188] By adopting the technical solution of this embodiment, the number of tabs 224 led out of the electrode assembly 220 can be reduced to facilitate the bending of the tabs 224; the number of tab groups 222 is multiple, and the number of tabs 224 in a single tab group 222 is small, so the bending of the tab group 222 is simpler and more convenient. In this way, the method of bending the tab groups 222 in groups is adopted, and the bending operation of the tab groups 222 is also more time-saving and labor-saving.

[0189] In another embodiment of the present application, the number of the tabs 224 in the tab group 222 close to the inner circle of the pole piece 223 is N3, and the number of the tabs 224 in the tab group 222 close to the outer circle of the pole piece 223 is N4, where N3>N4.

[0190] The inner circle of the pole piece 223 may refer to the first circle of the pole piece 223 , and the inner circle of the pole piece 223 is arranged close to and away from the axis of the main body 221 .

[0191] The outer circle of the pole piece 223 may refer to the last circle of the pole piece 223 , and the outer circle of the pole piece 223 is arranged away from the axis of the main body 221 .

[0192] By adopting the technical solution of this embodiment, the smaller the width of the pole ear 224 close to the inner circle of the pole piece 223, the larger the width of the pole ear 224 close to the outer circle of the pole piece 223, and the number of pole ears 224 in the pole ear group 222 close to the inner circle of the pole piece 223 is greater than the number of pole ears 224 in the pole ear group 222 close to the outer circle of the pole piece 223, that is, the pole ears 224 in the pole ear group 222 close to the outer circle of the pole piece 223 are arranged more sparsely, while the pole ears 224 in the pole ear group 222 close to the inner circle of the pole piece 223 are arranged more densely. The collection can facilitate the bending of the tab group 222; in addition, the flow area of ​​the tab group 222 close to the outer circle of the pole piece 223 and the flow area of ​​the tab group 222 close to the inner circle of the pole piece 223 are not much different, which is conducive to better charging and discharging of the battery cell 20; and, when the flow area of ​​the tab group 222 close to the outer circle of the pole piece 223 and the flow area of ​​the tab group 222 close to the inner circle of the pole piece 223 are the same, the tab 224 in the tab group 222 close to the inner circle will not be designed to be too wide and cannot be bent.

[0193] It should be noted that the width of the tab 224 may refer to the size of the tab 224 in the circumferential direction of the main body 221 before the tab 224 is bent.

[0194] In another embodiment of the present application, the number of the tabs 224 in the plurality of tab groups 222 gradually decreases along a first direction, where the first direction is a direction from the inner circle of the pole piece 223 to the outer circle of the pole piece 223 .

[0195] The first direction, as shown in FIG. 14 , may refer to the X direction.

[0196] The number of tabs 224 in the multiple tab groups 222 gradually decreases along the first direction. It can be understood that the closer the tab group 222 is to the inner circle of the pole piece 223, the more tabs 224 there are, and the closer the tab group 222 is to the outer circle of the pole piece 223, the fewer tabs 224 there are.

[0197] By adopting the technical solution of this embodiment, the width of the pole lug 224 closer to the inner circle of the pole piece 223 is generally smaller, and the width of the pole lug 224 closer to the outer circle of the pole piece 223 is smaller, and the number of pole lugs 224 in the pole lug group 222 closer to the outer circle of the pole piece 223 is smaller and smaller. In this way, the smaller the width of the pole lug 224, the more pole lugs 224 there are in the pole lug group 222, and the larger the width of the pole lug 224, the smaller the number of pole lugs 224 in the pole lug group 222. The pole lug group 222 is simple to bend. In addition, the number of pole lugs 224 led out from the electrode assembly 220 is also large, which is conducive to faster charging and discharging of the battery cell 20.

[0198] In another embodiment, the number of the tabs 224 in the plurality of tab groups 222 may be reduced in a step-by-step manner along the first direction, that is, there may be a situation where the number of the tabs 224 in two adjacent tab groups 222 is the same.

[0199] In another embodiment of the present application, as shown in Figures 13 and 14, the spacing between the connecting portions 2222 of two adjacent tab groups 222 near the inner circle of the pole piece 223 is L5, and the spacing between the connecting portions 2222 of two adjacent tab groups 222 near the outer circle of the pole piece 223 is L6, where L6>L5.

[0200] As shown in Figures 13 and 14, before the tab group 222 is bent, the spacing between the connecting portions 2222 of two adjacent tab groups 222 may refer to the spacing between the two adjacent tab groups 222; after the tab group 222 is bent, the welding portion 2221 is parallel to the end face of the main body 221, and the welding portions 2221 of multiple tab groups 222 will be stacked together, but there is a spacing between the connecting portions 2222 of two adjacent tab groups 222.

[0201] By adopting the technical solution of this embodiment, the number of the pole lug groups 222 near the inner circle of the pole lug 224 is large, while the number of the pole lug groups 222 near the outer circle of the pole lug 224 is small, and the width of the pole lug 224 near the inner circle of the pole piece 223 is small, and the width of the pole lug 224 near the outer circle of the pole piece 223 is large. In this way, the flow area of ​​the electrode assembly 220 near the outer circle of the pole piece 223 and the flow area near the inner circle of the pole piece 223 are not much different, which is conducive to better charging and discharging of the battery cell 20; and, when the flow area of ​​the electrode assembly 220 near the outer circle of the pole piece 223 and the flow area near the inner circle of the pole piece 223 are the same, the pole lug 224 in the pole lug group 222 near the inner circle will not be designed to be too wide and cannot be bent.

[0202] In another embodiment of the present application, as shown in FIG13 and FIG14 , the distance between the connecting portions 2222 of two adjacent tab groups 222 gradually increases along a first direction, where the first direction is from the inner circle of the pole piece 223 to the outer circle of the pole piece 223 .

[0203] The spacing between the connecting parts 2222 of two adjacent pole ear groups 222 gradually increases along the first direction, and the first direction is the direction from the inner circle of the pole piece 223 to the outer circle of the pole piece 223. It can be understood that the closer to the inner circle of the pole piece 223, the more the number of pole ear groups 222, and the closer to the outer circle of the pole piece 223, the fewer the number of pole ear groups 222, and the smaller the width of the pole ear 224 close to the inner circle of the pole piece 223, and the longer the length close to the outer circle of the pole piece 223.

[0204] By adopting the technical solution of this embodiment, the number of the tab groups 222 closer to the inner circle of the pole piece 223 increases, and the number of the tab groups 222 closer to the outer circle of the pole piece 223 decreases. In this way, the difference between the flow area near the inner circle of the pole piece 223 and the flow area near the outer circle of the pole piece 223 is smaller, which is beneficial to improving the performance of the battery cell 20.

[0205] In another embodiment, the distance between the connecting portions 2222 of two adjacent tab groups 222 may be reduced in a step-wise manner along the first direction, that is, the distance between the connecting portions 2222 of two adjacent tab groups 222 may be the same.

[0206] In another embodiment of the present application, the electrode assembly 220 includes a plurality of tab groups 222 , and the plurality of tab groups 222 are spaced apart along the circumference of the main body 221 .

[0207] Multiple tab groups 222 can be dispersed along the circumference of the main body 221, so that the number of tabs 224 in a single tab group 222 can be set to be smaller, which facilitates the bending of the tab group 222; wherein, one tab group 222 here can be obtained by adopting the above-mentioned method of leading out the tabs 224 at intervals, that is, a spacing gap 2223 can be formed in the tab group 222, and the spacing gap 2223 divides the tab group 222 into multiple parts arranged radially along the main body 221. With this design, the number of tabs 224 in the tab group 222 can be set to be smaller, which facilitates the bending of the tab group 222.

[0208] By adopting the technical solution of this embodiment, the tab groups 222 are dispersed, and the number of tabs 224 in a single tab group 222 can be set to be smaller, so as to facilitate the bending of the tab group 222 .

[0209] In another embodiment of the present application, as shown in FIG. 15 , at least one of the welding segment 2241 and the connecting segment 2243 is provided with a hollow structure 2245 .

[0210] 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 a hollow structure 2245, wherein 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.

[0211] 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 .

[0212] In another embodiment of the present application, as shown in Figure 15, 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, and 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.

[0213] The welding section 2241 is divided into a plurality of welding sections 2242 along its length. Adjacent welding sections 2242 are separated, and a gap is formed between adjacent welding sections 2242, forming a hollow structure 2245. For example, the welding section 2241 is provided with a plurality of through slots (i.e., gaps) extending through the welding section 2241 along its height.

[0214] 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, making the bending of the tab 224 time-saving and labor-saving.

[0215] In another embodiment of the present application, in combination with Figure 15, 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, and the plurality of connecting sections 2244 are arranged at intervals along the circumference of the main body 221, and the gap between two connected connecting sections 2244 forms a hollow structure 2245.

[0216] The connecting section 2243 is divided into a plurality of connecting sections 2244 along the circumference of the main body 221. Adjacent connecting sections 2244 are separated, and a gap is formed between adjacent connecting sections 2244, forming a hollow structure 2245. For example, the connecting section 2243 is provided with a plurality of through slots (i.e., gaps) extending through the connecting section 2243 along its height direction.

[0217] By adopting the technical solution of this embodiment, the connecting section 2243 is divided into multiple connecting sections 2244 in the circumferential direction of the main body 221, and 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 small, making the bending of the tab 224 convenient and quick.

[0218] In another embodiment of the present application, as shown in FIG. 15 , when both the welding segment 2241 and the connecting segment 2243 are provided with a hollow structure 2245 , a plurality of welding segments 2242 and a plurality of connecting segments 2244 are connected in a one-to-one correspondence.

[0219] The multiple welding sections 2242 in the welding section 2241 and the multiple connecting sections 2244 in the connecting section 2243 are connected one by one. It can be understood that before the pole ear 224 is bent, the pole ear 224 is provided with multiple through grooves that penetrate the pole ear 224 along the height direction, thereby dividing the pole ear 224 into multiple disconnected structures, each section including a welding section 2242 and a connecting section 2244.

[0220] By adopting the technical solution of this embodiment, the tab 224 is divided into a multi-section disconnected structure, the tab 224 is easy to bend, and the bending process of the tab 224 is more time-saving and labor-saving.

[0221] In another embodiment of the present application, as shown in Figures 17 to 20, 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 circle of the pole 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 circle of the pole tab 224.

[0222] During the bending process of the pole tab 224, the pole tab 224 bends toward the axis of the main body 221; after the bending is completed, 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 circle of the pole tab 224. This structural design makes the pole tab 224 concentrated toward the axis of the main body 221, and the structure is compact, which is conducive to improving the energy density of the battery cell 20.

[0223] During the bending process of the pole ear 224, the pole ear 224 is bent away from the axis of the main body 221; after the bending is completed, 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 circle of the pole ear 224. This structural design reduces the risk of the pole ear 224 near the outer circle of the pole piece 223 being retracted toward the axis of the main body 221 and then bent toward the outer circle of the pole piece 223. This can alleviate the risk of the pole ear 224 near the outer circle of the pole piece 223 expanding outward, which is beneficial to improving the performance of the battery cell 20.

[0224] By adopting the technical solution of this embodiment, the bending direction of the tab 224 can be flexibly set to meet different usage requirements.

[0225] In another embodiment of the present application, as shown in combination with FIG. 7 and FIG. 16 , the welding portion 2221 is located between the main body 221 and the adapter 230 .

[0226] By adopting the technical solution of this embodiment, after the tab 224 is bent, the adapter 230 can be placed on the welding portion 2221 for welding, and the assembly operation is simple.

[0227] In another embodiment of the present application, as shown in Figures 7 and 16, the battery cell 20 further includes a connector 240, and the connector 240 is welded between the welding portion 2221 and the adapter 230; and / or, a welding portion 2221 is welded between the connector 240 and the adapter 230.

[0228] The connector 240 may refer to a conductive component that is stacked and welded with the welding portion 2221 and the adapter 230, wherein the connector 240 may be located between the welding portion 2221 and the adapter 230, or between the welding portion 2221 and the main portion 221, or both between the welding portion 2221 and the adapter 230 and between the welding portion 2221 and the main portion 221; the connector 240 may be made of conductive metal, such as copper, aluminum, etc.

[0229] During the actual welding process, after the pole tab 224 is folded and before the pole tab 224 is bent, the welding section 2241 is in a vertical state, and the welding laser welds the connector 240 and the welding section 2241 together in a radial direction of the main body 221, and then the pole tab 224 is bent and welded to the adapter 230; wherein, the welding laser welds the connector 240 and the welding section 2241 in parallel with the radial direction of the main body 221, so that even if the welding laser welds through the pole tab 224 and the connector 240, it will not damage the main body 221, thereby improving the yield rate of the battery cell 20.

[0230] By adopting the technical solution of this embodiment, the provision of the connecting member 240 can increase the welding thickness, reduce the risk of damaging the main body 221 due to welding through, and improve the welding quality of the welding portion 2221 and the adapter 230.

[0231] In another embodiment of the present application, as shown in FIG7 and FIG8 , the thickness of the welding portion 2221 is H1, the thickness of the connecting member 240 is H2, the number of the connecting members 240 is N, and the thickness of the welding position of the adapter 230 and the welding portion 2221 is H3, wherein,

[0232] The thickness H1 of the welding portion 2221 may refer to the dimension of the welding portion 2221 in the axial direction of the main body portion 221 ; the thickness H1 of the welding portion 2221 may also refer to the sum of the thicknesses of all welding segments 2241 in the welding portion 2221 .

[0233] The thickness H2 of the connector 240 may refer to the dimension of the welding portion 2221 in the axial direction of the main body 221. The number of connectors 240 may be one, two, or three or more. For example, as shown in FIG7 , there is one connector 240, which is welded between the welding portion 2221 and the adapter 230. In another embodiment, there may be two connectors 240, one of which is provided on the side of the welding portion 2221 facing the main body 221, and the other connector 240 is provided on the side of the welding portion 2221 facing the adapter 230. In other embodiments, the side of the welding portion 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 portion 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.

[0234] The welding position between the adapter 230 and the welding part 2221 may, for example, refer to 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 between the adapter 230 and the welding part 2221 may refer to the dimension of the welding position between the adapter 230 and the welding part 2221 in the axial direction of the main body 221.

[0235] H1+N×H2 may refer to the sum of the thicknesses of the welding portion 2221 and all the connecting members 240 .

[0236] It can be understood that the sum of the thicknesses of the welding portion 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 welding portion 2221 .

[0237] By adopting the technical solution of this embodiment, The design makes the sum of the thickness of the welding part 2221 and all the connecting parts 240 greater than or equal to the thickness H3 of the welding position between the adapter 230 and the welding part 2221, so that the sum of the thickness of the welding part 2221 and all the connecting parts 240 is larger than the thickness of the welding position of the welding part 2221, and the welding part 2221 and the connecting parts 240 are not easily welded through, which can reduce the damage of the main body 221, improve the welding quality, and improve the yield rate of the battery cell 20.

[0238] In one embodiment, The value of 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.

[0239] In another embodiment of the present application, as shown in FIG. 7 and FIG. 8 , when a connecting member 240 is welded between the welding portion 2221 and the adapter 230 , a thickness H1 of the welding portion 2221 is greater than a thickness H2 of the connecting member 240 .

[0240] By adopting the technical solution of this embodiment, when the welding portion 2221 is welded to the adapter 230, since the connecting member 240 is located between the welding portion 2221 and the adapter 230, the welding portion 2221 is welded from the connecting member 240, and the thickness H1 of the welding portion 2221 is greater than the thickness H2 of the connecting member 240. The welding portion 2221 is not easily welded through, reducing the risk of damage to the main body 221, which is beneficial to improving the welding quality and the yield rate of the battery cell 20.

[0241] In another embodiment of the present application, as shown in combination with FIG. 7 and FIG. 8 , the thickness of the connecting member 240 is H2, wherein 0.2 mm ≤ H2 ≤ 0.4 mm.

[0242] 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 reasonably set. On the one hand, it can reduce the risk of damage to the main body 221 caused by welding through the welding portion 2221; on the other hand, the connector 240 will not take up too much space, which is beneficial to improving the volume energy density of the battery cell 20; with this design, the thickness H2 of the connector 240 will not easily cause the connector 240 and the welding portion 2221 to be welded through due to being designed too small; and the thickness H2 of the connector 240 will not take up more space of the battery cell 20 due to being designed too large.

[0243] In another embodiment of the present application, as shown in Figures 17 to 20 , the adapter 230 is located between the welding portion 2221 and the main body 221 .

[0244] By adopting the technical solution of this embodiment, the adapter 230 is located between the welding portion 2221 and the main body 221. In this way, during welding, welding is carried out from the welding portion 2221 to the adapter 230. The structural strength of the adapter 230 is generally better than the structural strength of the welding portion 2221, making it difficult for the adapter 230 to be welded through, thereby reducing the risk of damage to the main body 221, which is beneficial to improving the welding quality and the yield rate of the battery cell 20.

[0245] In another embodiment of the present application, as shown in FIG. 17 , FIG. 18 and FIG. 21 , the adapter 230 is provided with a penetration hole 231 , and the connecting portion 2222 is penetrated through the penetration hole 231 .

[0246] The through hole 231 may refer to a through hole structure provided in the adapter 230 , which is provided for 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 toward the axis of the main body 221 or away from the axis of the main body 221 .

[0247] By adopting the technical solution of this embodiment, after the tab group 222 passes through the through hole 231 and is bent, the welding portion 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 beneficial to improving the welding quality and the yield rate of the battery cell 20.

[0248] In another embodiment of the present application, in combination with Figures 19, 20 and 21, when the end of the welding portion 2221 facing away from the connecting portion 2222 is located on the side of the connecting portion 2222 close to the inner circle of the pole ear 224, the connecting portion 2222 is located on the side of the adapter 230 close to the outer circle of the pole piece 223.

[0249] During assembly, the adapter 230 is placed on the side of the tab group 222 close to the inner circle of the tab 224, and then the tab group 222 is bent toward the axis of the main body 221; after bending, the welding portion 2221 is located on the side of the adapter 230 facing away from the main body 221, the connecting portion 2222 is located on the side of the adapter 230 close to the outer circle of the pole piece 223, and the end of the welding portion 2221 facing away from the connecting portion 2222 is located on the side of the connecting portion 2222 close to the inner circle of the tab 224.

[0250] By adopting the technical solution of this embodiment, the tab group 222 passes directly through the side of the adapter 230 close to the outer circle of the pole piece 223 and then bends, so that the welding portion 2221 can be located on the side of the adapter 230 facing away from the main body 221. In this way, there is no need to open a penetration structure in the adapter 230, which facilitates processing and manufacturing.

[0251] In another embodiment of the present application, as shown in Figures 19, 20 and 21, a notch 232 is provided on one side of the adapter 230 close to the outer circle of the pole piece 223, and the connecting portion 2222 is located in the notch 232.

[0252] The notch 232 may be a notch structure for avoiding or accommodating the connecting portion 2222. The notch 232 may have various shapes, such as a U-shape. For example, the notch 232 may be formed by linearly removing a portion of material from the periphery of the adapter 230. This design is simple and convenient to manufacture.

[0253] By adopting the technical solution of this embodiment, the notch 232 can provide installation space for the connecting portion 2222, and the connecting portion 2222 is not easy to protrude outside the outer peripheral wall of the main body 221. A certain distance can also be maintained between the connecting portion 2222 and the inner wall of the outer shell 210, thereby reducing the risk of extrusion between the connecting portion 2222 and the inner wall of the outer shell 210, which is beneficial to improving the reliability of the battery cell 20. The overall structure is compact, which is beneficial to improving the energy density of the battery cell 20.

[0254] In another embodiment of the present application, as shown in Figures 22 to 24, the battery cell 20 includes multiple tab groups 222, and the welding portions 2221 of a portion of the tab groups 222 are located between the main body 221 and the adapter 230; the welding portions 2221 of another portion of the tab groups 222 are located on the side of the adapter 230 facing away from the main body 221.

[0255] By adopting the technical solution of this embodiment, the 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 portion 2221 of the tab group 222 can also be flexibly set, making assembly simpler and more convenient.

[0256] In one embodiment, the adapter 230 includes a flipping portion 233 and a fixing portion 234 that are connected to each other. The flipping portion 233 is welded to the welding portion 2221 , and the flipping portion 233 can flip relative to the fixing portion 234 .

[0257] For example, as shown in FIG25, the flip portion 233 may refer to the portion where the adapter 230 is welded to the welding portion 2221, and the fixed portion 234 may refer to the portion of the adapter 230 other than the flip portion 233. The fixed portion 234 and the flip portion 233 are divided by the dotted line in FIG25. The flip portion 233 can be flipped upward relative to the fixed portion 234 along the dotted line. In this way, before the tab group 222 is bent, the flip portion 233 can be flipped upward, so that the fixed portion 234 and the flip zone are at a certain angle. At this time, the welding laser can The welding portion 2221 and the flip portion 233 are welded together along the radial direction of the main body 221. In this way, even if the welding laser penetrates the welding portion 2221, it will not be irradiated to the main body 221 and damage the main body 221, thereby reducing the risk of damage to the main body 221. After the welding is completed, the flip portion 233 and the tab group 222 are flipped and folded together, so that the welding portion 2221 and the flip portion 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 in the shell 210. The fixed portion 234 and the flip portion 233 are integrated components, that is, the material of the adapter 230 itself has the bendability to achieve this. Alternatively, the fixed portion 234 and the flip portion 233 are fixedly connected, and the flip portion 233 itself has the bendability to achieve this. Alternatively, the fixed portion 234 and the flip portion 233 are connected by a rotating structure. The rotating structure can be a rotating shaft structure, a hinge structure, a bendable component (such as a copper sheet, an aluminum sheet, etc.). A single adapter 230 can be provided with multiple flip portions 233, and the flip portions 233 can be welded to the tab groups 222 in a one-to-one correspondence. Of course, in another embodiment, a single flip portion 233 can be welded to multiple tab groups 222.

[0258] By adopting the design of this embodiment, the welding direction of the welding laser can be changed, thereby reducing the risk of the welding laser penetrating the welding portion 2221 and not striking the main body 221 and damaging the main body 221, thereby improving the performance of the battery cell 1100. The structure of the battery cell 20 is described below with reference to some specific embodiments.

[0259] Specific embodiment 1

[0260] In this specific embodiment, as shown in Figures 4 to 10, the battery cell 20 includes a shell 211, an electrode assembly 220 and an adapter 230. The electrode assembly 220 and the adapter 230 are both arranged in the installation cavity 2111 of the shell 210. 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 a pole piece 223. At least two turns of the pole piece 223 lead out a tab 224 from the end face of the main body 221. The pole piece 223 leads out a plurality of tabs 224 arranged radially along the main body 221 to form a tab group 222; the tab group 222 is bent toward the end of the main body 221, and the tabs 224 in the tab group 222 are 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 curved; the tab group 222 is bent toward the end of the main body 221. The welding sections 2241 of the multiple tabs 224 in 22 are stacked along the axial direction of the main body 221 to form a welding section 2221, and the connecting sections 2243 of the multiple tabs 224 in the tab group 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; a pre-welding structure 225 is provided at the end of the welding section 2221 facing away from the connecting section 2222 to stably connect the tabs 224 together, which helps to form a dense welding section 2221 to improve the welding quality; the welding section 2221 is located between the main body 221 and the adapter 230, and a connecting piece 240 is welded between the adapter 230 and the welding section 2221 to increase the welding thickness, reduce the risk of welding through, reduce welding defects, and improve the welding quality.

[0261] Specific embodiment 2

[0262] In this specific embodiment, as shown in FIG. 11 and FIG. 12 , this specific embodiment differs from specific embodiment 1 in that the length L1 of the connecting section 2243 is smaller than the length L7 of the welding section 2241 , which facilitates the bending of the tab 224 .

[0263] Specific embodiment 3

[0264] In this specific embodiment, as shown in Figures 13 and 14 , this specific embodiment differs from specific embodiment 1 in that: the electrode assembly 220 has multiple tab groups 222 extending therefrom, the multiple tab groups 222 being spaced apart along the radial direction of the main body 221, and the spacing between two adjacent tab groups 222 increasing along a first direction, the first direction being the direction from the inner circle of the electrode sheet 223 to the outer circle of the electrode sheet 223. The tabs 224 are divided into multiple groups, so that the number of tabs 224 in each tab group 222 can be set to be smaller, to facilitate the bending of the tab group 222. In addition, the reasonable arrangement of the multiple tab groups 222 can also take into account the flow area of ​​the inner and outer circles of the electrode sheet 223, thereby improving the performance of the battery cell 20.

[0265] Specific embodiment 4

[0266] In this specific embodiment, as shown in Figure 15, the difference between this specific embodiment and specific embodiment 1 is that: the tab group 222 is divided into multiple sections along the width direction of the tab 224, and the adjacent sections are completely disconnected, so that the welding section 2241 of the tab 224 is divided into multiple completely disconnected welding sections 2242, and the connecting section 2243 of the tab 224 is divided into multiple completely disconnected connecting sections 2244, and the welding sections 2242 and the connecting sections 2244 are connected one by one, and the gap between the two adjacent welding sections 2242 forms a hollow structure 2245, and the gap between the two adjacent connecting sections 2244 forms a hollow structure 2245. Such a multi-segment structure design can facilitate the bending of the tab group 222.

[0267] Specific embodiment 5

[0268] In this specific embodiment, as shown in Figure 16, the difference between this specific embodiment and specific embodiment 1 is that the connecting member 240 is located between the welding portion 2221 and the main body 221. On the one hand, the provision of the connecting member 240 increases the welding thickness and reduces the risk of welding through and damaging the main body 221; on the other hand, the structural strength of the connecting member 240 is usually better than that of the welding portion 2221, so that the connecting member 240 is not easy to weld through and damage the main body 221 during welding, which is beneficial to improving the welding quality and the yield rate of the battery cell 20.

[0269] Specific embodiment 6

[0270] In this specific embodiment, in combination with Figures 17, 18 and 21, the difference between this specific embodiment and specific embodiment 1 is that: the battery cell 20 does not include a connector 240, the adapter 230 is provided with a penetration hole 231, and the tab group 222 passes through the penetration hole 231 and is bent toward the outer circle of the pole piece 223; after bending, the welding portion 2221 is located on the side of the adapter 230 facing away from the main body 221, and the connecting portion 2222 is penetrated in the penetration hole 231. Usually, the structural strength of the adapter 230 is better than that of the welding portion 2221, so that the connector 240 is not easily welded through and damages the main body 221 during welding, which is beneficial to improving the welding quality and the yield rate of the battery cell 20.

[0271] Specific embodiment 7

[0272] In this specific embodiment, in combination with Figures 19, 20 and 21, the difference between this specific embodiment and specific embodiment 6 is that: the adapter 230 is provided with a notch 232 near the outer circle of the pole piece 223, and the pole ear group 222 is bent toward the inner circle of the pole piece 223 after passing through the notch 232; after bending, the welding portion 2221 is located on the side of the adapter 230 facing away from the main body 221, and the connecting portion 2222 is passed through the notch 232.

[0273] Specific embodiment 8

[0274] In this specific embodiment, as shown in FIG22 , this specific embodiment differs from specific embodiment 6 in that: the electrode assembly 220 has two tab groups 222 extending therefrom, and the adapter 230 is provided with a notch 232 and a through-hole 231. One of the tab groups 222 passes through the notch 232 and is bent toward the inner circle of the electrode piece 223. After bending, the welding portion 2221 of the tab group 222 is located on the side of the adapter 230 facing away from the main body 221, and the connecting portion 2222 of the tab group 222 is penetrated within the notch 232. The other tab group 222 passes through the through-hole 231 and is bent toward the outer circle of the electrode piece 223. After bending, the welding portion 2221 of the tab group 222 is located on the side of the adapter 230 facing away from the main body 221, and the connecting portion 2222 of the tab group 222 is penetrated within the through-hole 231.

[0275] Specific embodiment 9

[0276] In this specific embodiment, as shown in FIG23 , this specific embodiment differs from specific embodiment 8 in that: the adapter 230 is provided with a notch 232, and one of the tab groups 222 passes through the notch 232 and is bent toward the inner circle of the pole piece 223. After bending, the welding portion 2221 of the tab group 222 is located on the side of the adapter 230 facing away from the main body 221, and the connecting portion 2222 of the tab group 222 is passed through the notch 232. The other tab group 222 is located between the adapter 230 and the main body 221, and is bent toward the outer circle of the pole piece 223; after bending, the welding portion 2221 of the tab group 222 is located between the adapter 230 and the main body 221.

[0277] Specific embodiment 10

[0278] In this specific embodiment, as shown in Figure 23, the difference between this specific embodiment and specific embodiment 8 is that: the electrode assembly 220 also leads out a group of tab groups 222, and the tab group 222 is located between the adapter 230 and the main body 221, and the tab group 222 is bent toward the outer circle of the electrode piece 223; after bending, the welding portion 2221 of the tab group 222 is located between the adapter 230 and the main body 221.

[0279] In another embodiment of the present application, in conjunction with Figures 4 to 10, a method for manufacturing a battery cell 20 is provided, which is used to manufacture the battery cell 20 of the above embodiment. The method for manufacturing the battery cell 20 includes the following steps:

[0280] The tab group 222 of the electrode assembly 220 is bent toward the end of the main body 221 of the electrode assembly 220, wherein the main body 221 is a cylindrical structure formed by winding the pole piece 223, and at least two turns of the pole piece 223 lead out the pole tab 224 from the end surface of the main body 221. The pole piece 223 leads out multiple pole tabs 224 arranged radially along the main body 221 to form the tab group 222; the pole tabs 224 in the tab group 222 are bent to form a welding section 2241 and a connecting section 2243, and the welding sections 2241 of the multiple pole tabs 224 are stacked along the axial direction of the main body 221 to form a welding section 2221, and the connecting sections 2243 of the multiple pole tabs 224 are stacked along the radial direction of the main body 221 to form a connecting section 2222;

[0281] The adapter 230 is welded to the welding portion 2221 , and the adapter 230 and the welding portion 2221 are stacked along the axial direction of the main body 221 ;

[0282] The welded adapter 230 and electrode assembly 220 are installed into the mounting cavity 2111 of the housing 210 .

[0283] The manufacturing method of the battery cell 20 of the embodiment of the present application is to first bend the tab group 222 to form the welding portion 2221 and the connecting portion 2222, and then weld the welding portion 2221 and the adapter 230 together. Finally, the welded electrode assembly 220 and the adapter 230 are installed in the installation cavity 2111 of the shell 210. In this process, the welding portion 2221 formed after the tab group 222 is bent, and the welding section 2241 in the welding portion 2221 can be flatly and tightly fitted together to form a tight welding portion 2221, thereby reducing the problem of poor welding between the welding portion 2221 and the adapter 230, which is beneficial to improving the performance of the battery cell 20.

[0284] In another embodiment of the present application, as shown in combination with FIG. 9 and FIG. 10 , before the tab group 222 is bent, the tab group 222 is folded along the stacking direction of the welding section 2241 .

[0285] Before the tab assembly 222 is bent, as shown in FIG. 9 , the stacking direction of the welding segments 2241 may refer to the radial direction of the main body 221 .

[0286] By adopting the technical solution of this embodiment, the extrusion and contraction can make the bent welding section 2241 fit together more tightly to form a tighter welding portion 2221, reducing the risk of welding defects such as cold welding and welding through, and is more conducive to improving the welding quality of the adapter 230 and the tab 224.

[0287] In another embodiment of the present application, as shown in conjunction with FIG. 11 and FIG. 12 , after the tabs 224 are folded and before the tabs 224 are bent, the tab group 222 is pre-welded so that the tabs 224 in the tab group 222 are welded together.

[0288] By adopting the technical solution of this embodiment, after the tabs 224 are folded and before the tabs 224 are bent, the tabs 224 in the tab group 222 are welded together by pre-welding. This can reduce the risk of the tabs 224 becoming loose after subsequent bending, so that the welding segments 2241 in the subsequent welding portion 2221 can fit together to form a tightly welded portion 2221, thereby reducing the risk of poor welding such as cold welding and weld penetration, which is beneficial to improving the welding quality of the welding portion 2221 and the adapter 230.

[0289] In another embodiment of the present application, as shown in combination with FIG. 9 and FIG. 10 , the pre-welded tab group 222 is located at an end facing away from the main body 221 .

[0290] By adopting the technical solution of this embodiment, pre-welding is performed on the end of the tab group 222 facing away from the main body 221 . After welding, the end of the tab group 222 close to the main body 221 is in a free state to facilitate bending of the tab group 222 .

[0291] In another embodiment of the present application, as shown in FIG2 , a battery 1100 is provided, including the battery cell 20 according to the above embodiment, and / or including a method for manufacturing the battery cell 20 according to the above embodiment to obtain the battery cell 20.

[0292] In another embodiment of the present application, as shown in FIG1 , an electrical device is provided, including a battery 1100 as described in the above embodiment.

[0293] The above description of the various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced with each other and will not be repeated herein for the sake of brevity.

[0294] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, wherein: include, A housing having a mounting cavity; An electrode assembly is located in the mounting cavity, the electrode assembly comprises a main body and a tab group, the main body is a cylindrical structure formed by winding a pole piece, at least two turns of the pole piece lead out a tab from the end face of the main body, and the pole piece leads out a plurality of tabs arranged radially along the main body to form the tab group; the tab group is bent toward the end of the main body, and the tabs in the tab group are bent to form a welding section and a connecting section, the connecting section is connected between the main body and the welding section, and the connecting section is curved; the welding sections of the plurality of tabs in the tab group are stacked along the axial direction of the main body to form a welding portion, and the connecting sections of the plurality of tabs in the tab group are stacked along the radial direction of the main body to form a connecting portion; and The adapter is stacked with the welding portion along the axial direction of the main body, and the adapter is welded to the welding portion.

2. The battery cell according to claim 1, wherein: The length of the connecting section is L1, and the radius of a circle of the pole piece corresponding to the connecting section is R, wherein:

3. The battery cell according to claim 2, wherein:

4. The battery cell according to any one of claims 1 to 3, wherein: The length of the connecting section in at least one of the electrode tabs is shorter than the length of the welding section.

5. The battery cell according to any one of claims 1 to 4, wherein: The tab group is provided with a pre-welding structure, and the pre-welding structure is used to connect a plurality of tabs in the tab group.

6. The battery cell according to claim 5, wherein: The pre-welding structure is arranged at the welding portion.

7. The battery cell according to claim 6, wherein: The distance between the pre-welding structure and the connecting portion is L2, wherein 0.1 mm≤L2≤10 mm.

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

9. The battery cell according to any one of claims 5 to 8, wherein: The pre-welding structure is located at an end of the welding portion facing away from the connecting section.

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

11. The battery cell according to any one of claims 1 to 10, wherein: The total number of turns of the pole piece is N1, and the total number of turns of the pole piece connected to the pole lug is N2, wherein, 12. The battery cell according to claim 11, wherein:

13. The battery cell according to any one of claims 1 to 12, wherein: The pole piece leads out the pole lugs from the end surface of the main body at intervals to form a plurality of pole lug groups, and the connecting parts of the plurality of pole lug groups are arranged at intervals along the radial direction of the main body.

14. The battery cell according to claim 13, wherein: The number of the pole lugs in the pole lug group close to the inner circle of the pole piece is N3, and the number of the pole lugs in the pole lug group close to the outer circle of the pole piece is N4, wherein N3>N4.

15. The battery cell according to claim 14, wherein: The number of the pole lugs in the plurality of pole lug groups gradually decreases along a first direction, and the first direction is a direction from the inner circle of the pole piece to the outer circle of the pole piece.

16. The battery cell according to any one of claims 13 to 15, wherein: The distance between the connecting parts of two adjacent pole lug groups near the inner circle of the pole piece is L5, and the distance between the connecting parts of two adjacent pole lug groups near the outer circle of the pole piece is L6, wherein L6>L5.

17. The battery cell according to claim 16, wherein: The distance between the connecting parts of two adjacent pole lug groups gradually increases along a first direction, and the first direction is a direction from the inner circle of the pole piece to the outer circle of the pole piece.

18. The battery cell according to any one of claims 1 to 17, wherein: The electrode assembly includes a plurality of electrode tab groups, and the plurality of electrode tab groups are arranged at intervals along the circumference of the main body.

19. The battery cell according to any one of claims 1 to 18, wherein: At least one of the welding section and the connecting section is provided with a hollow structure.

20. The battery cell according to claim 19, wherein: In the case where the welding section is provided with the hollow structure, the welding section comprises 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; In the case where the connecting section is provided with the hollow structure, the connecting section includes a plurality of connecting sections connected to the welding section, the plurality of connecting sections are arranged at intervals along the circumference of the main body, and the gap between two connected connecting sections forms the hollow structure.

21. The battery cell according to claim 20, wherein: In the case where both the welding section and the connecting section are provided with the hollow structure, a plurality of the welding sections and a plurality of the connecting sections are connected in a one-to-one correspondence.

22. The battery cell according to any one of claims 1 to 21, wherein: The end of the welding portion facing away from the connecting portion is located on a side of the connecting portion facing the inner ring of the pole lug; or, the end of the welding portion facing away from the connecting portion is located on a side of the connecting portion facing away from the inner ring of the pole lug.

23. The battery cell according to any one of claims 1 to 22, wherein: The welding portion is located between the main body and the adapter.

24. The battery cell according to claim 23, wherein: The battery cell further includes a connecting piece, and the connecting piece is welded between the welding portion and the adapter; and / or the welding portion is welded between the connecting piece and the adapter.

25. The battery cell according to claim 24, wherein: The thickness of the welding part is H1, the thickness of the connecting piece is H2, the number of the connecting pieces is N, and the thickness of the welding position between the adapter and the welding part is H3. Among them, among them, 26. The battery cell according to claim 24 or 25, wherein: In a case where the connecting member is welded between the welding portion and the adapter, the thickness of the welding portion is greater than the thickness of the connecting member.

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

28. The battery cell according to any one of claims 1 to 22, wherein: The adapter is located between the welding portion and the main body portion.

29. The battery cell according to claim 28, wherein: The adapter is provided with a penetration hole, and the connecting portion is penetrated through the penetration hole.

30. The battery cell according to claim 28, wherein: In the case where the end of the welding portion facing away from the connecting portion is located on a side of the connecting portion close to the inner ring of the pole lug, the connecting portion is located on a side of the adapter close to the outer ring of the pole piece.

31. The battery cell according to claim 30, wherein: A notch is provided on one side of the adapter close to the outer ring of the pole piece, and the connecting portion is located in the notch.

32. The battery cell according to any one of claims 1 to 31, wherein: The battery cell comprises a plurality of tab groups, wherein the welding portions of a portion of the tab groups are located between the main body and the adapter; and the welding portions of another portion of the tab groups are located on a side of the adapter facing away from the main body.

33. The battery cell according to any one of claims 1 to 32, wherein: The adapter comprises a flipping portion and a fixing portion connected to each other, the flipping portion is welded to the welding portion, and the flipping portion can be flipped relative to the fixing portion.

34. A method for manufacturing a battery cell, wherein: Used to manufacture a battery cell according to any one of claims 1 to 33, the battery cell manufacturing method comprising the following steps: The pole lug group of the electrode assembly is bent toward the end of the main body of the electrode assembly, wherein the main body is a cylindrical structure formed by winding pole pieces, at least two turns of the pole pieces lead out pole lugs from the end surface of the main body, and the pole pieces lead out a plurality of pole lugs arranged radially along the main body to form the pole lug group; the pole lugs in the pole lug group are bent to form the welding section and the connecting section, and the welding sections of the plurality of pole lugs are stacked along the axial direction of the main body to form a welding portion, and the connecting sections of the plurality of pole lugs are stacked along the radial direction of the main body to form the connecting portion; The adapter is welded to the welding portion, and the adapter and the welding portion are stacked along the axial direction of the main body; The welded adapter and the electrode assembly are installed into the mounting cavity of the housing.

35. The method for manufacturing a battery cell according to claim 34, wherein: Before the tab group is bent, the tab group is folded along the stacking direction of the welding section.

36. The method for manufacturing a battery cell according to claim 35, wherein: After the tabs are folded and before the tabs are bent, the tab group is pre-welded so that the tabs in the tab group are welded together.

37. The method for manufacturing a battery cell according to claim 36, wherein: The end of the tab group facing away from the main body is pre-welded.

38. A battery, wherein: A battery cell comprising the battery cell according to any one of claims 1 to 33, and / or a battery cell obtained by using the battery cell manufacturing method according to any one of claims 34 to 37.

39. An electrical device, wherein: Comprising the battery of claim 38.

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