Battery cell and battery pack
By designing arc-shaped walls on the tab assembly of the battery cell to increase the welding size and smoothly transition the connection, the problem of tabs deviating from the welding position was solved, thus improving welding yield and production quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SUNWODA MOBILITY ENERGY TECHNOLOGY CO LTD
- Filing Date
- 2025-06-17
- Publication Date
- 2026-06-16
AI Technical Summary
In a single battery cell, when the tabs are welded to the connecting pieces, some tabs may deviate from their welding positions, leading to welding abnormalities and affecting the welding yield.
The first electrode lug of the design has arc-shaped walls on both sides along the welding direction to increase the welding size, and the arc-shaped walls are smoothly connected to the side walls to enhance welding stability.
This improved the yield of ultrasonic welding between the tab assembly and the connecting piece, reduced the occurrence of welding abnormalities, and improved the production quality of the battery cell.
Smart Images
Figure CN224367082U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery technology, and in particular to a battery cell and a battery pack. Background Technology
[0002] The information disclosed in this background section is intended only to enhance the understanding of the general background of this disclosure and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art.
[0003] The fabrication of electrode assemblies in a single battery cell typically involves two processes: lamination and winding. After lamination or winding, the tabs in the electrode assembly need to be welded to the connecting tabs of the connecting terminals to achieve electrical connection between the terminals and the electrode assembly. However, the tab assembly consists of multiple tabs stacked together. After lamination or winding, adjacent tabs are prone to misalignment. This can cause some tabs to deviate from their welding positions and result in welding abnormalities during ultrasonic welding of the tab assembly and connecting tabs. Utility Model Content
[0004] In view of this, the purpose of this application is to provide a battery cell and a battery pack, which aims to solve the technical problem that some electrodes are prone to deviate from the welding position and cause welding abnormalities when ultrasonically welding electrode groups and connecting pieces.
[0005] To achieve the above objectives, the technical solution adopted in this application is as follows:
[0006] In a first aspect, embodiments of this application provide a battery cell having a first direction and a third direction perpendicular to each other, the battery cell comprising:
[0007] An electrode assembly includes an electrode body, a first tab group, and a second tab group. The first tab group and the second tab group are spaced apart along a first direction. The first tab group includes a plurality of first tabs stacked along a third direction. The second tab group includes a plurality of second tabs stacked along a third direction. The first tabs and the second tabs are respectively connected to the electrode body.
[0008] A connecting piece is welded to the first electrode tab to form a solder mark on the connecting piece, the solder mark being located inside the first electrode tab, and the first electrode tab having arc-shaped walls that bend away from the solder mark on both sides along the first direction.
[0009] In one embodiment of the first aspect, the battery cell has a second direction perpendicular to the first direction and the third direction, the first tab has a centerline parallel to the second direction, the first tab includes a main body and a plurality of widening portions disposed opposite each other along the first direction, the main body is connected between two adjacent widening portions, the dimension of each widening portion along the first direction is smaller than the dimension of the main body portion along the first direction; a portion of the solder mark is located within the widening portion, the widening portion protrudes in a direction away from the centerline, and the arcuate wall is located at the edge of the widening portion.
[0010] In one embodiment of the first aspect, a portion of the solder mark is located within the body portion, the body portion having a first sidewall and a second sidewall spaced apart, the first sidewall being connected to the electrode body, and the arcuate wall being smoothly connected to the first sidewall and the second sidewall respectively.
[0011] In one embodiment of the first aspect, the main body has an arcuate chamfer that curves away from the main body, the arcuate chamfer being connected to the arcuate wall and the second sidewall, respectively.
[0012] In one embodiment of the first aspect, the dimension of the second sidewall along the first direction is less than or equal to the dimension of the first sidewall along the first direction.
[0013] In one embodiment of the first aspect, the battery cell further includes a protective sheet located on the side of the first tab assembly away from the connecting tab along the third direction and connected to the first tab, wherein the protective sheet is made of the same material as the first tab.
[0014] In one embodiment of the first aspect, the battery cell further includes an insulating layer connected to the protective sheet on a side of the connecting sheet in a third direction away from the connecting sheet.
[0015] In one embodiment of the first aspect, the insulating layer is integrally formed with the protective sheet.
[0016] In one embodiment of the first aspect, the battery cell has a second direction perpendicular to the first direction and the third direction, the electrode body includes a first electrode, a second electrode, and a separator, the separator is disposed between the first electrode and the second electrode, the first tab is connected to the first electrode, the second tab is connected to the second electrode, the first electrode, the second electrode, and the separator are wound together to form the electrode body, or the first electrode, the second electrode, and the separator are stacked along the second direction to form the electrode body.
[0017] Secondly, embodiments of this application provide a battery pack including the battery cells described in any of the embodiments of the first aspect above.
[0018] The beneficial effects of this application are as follows:
[0019] In the battery cell provided in this application, the connecting piece is welded to the first electrode tab to form a solder mark on the connecting piece. Each first electrode tab has an arc-shaped wall that bends away from the solder mark on both sides along the first direction. The arc-shaped wall increases the size of each first electrode tab that can be ultrasonically welded in the first direction, thereby improving the situation where the electrode tab deviates from the welding position and causing welding abnormalities, and improving the yield of ultrasonic welding between the electrode tab assembly and the connecting piece.
[0020] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description
[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 This shows a schematic diagram of the electrode assembly from one perspective in the prior art;
[0023] Figure 2 A schematic diagram showing the relative positions of the tab assembly and the welding position in the prior art is shown;
[0024] Figure 3 An exploded structural diagram of the housing, cover plate, connecting piece and electrode assembly in an embodiment of this application is shown;
[0025] Figure 4 This shows a schematic diagram of the structure of the first electrode group and the second electrode group in an embodiment of this application.
[0026] Figure 5 A schematic diagram showing the relative positions of the first electrode group, the second electrode group, and the welding position in an embodiment of this application is shown;
[0027] Figure 6 This illustration shows a top view (top view) of the structure of the first and second electrode groups in an embodiment of this application.
[0028] Figure 7 This illustration shows a schematic diagram of the assembly structure of the first electrode group, the second electrode group, the connecting piece, and the protective piece in an embodiment of this application.
[0029] Explanation of key component symbols:
[0030] Explanation of component symbols in related technologies: 210 - tab group; 211 - tab; 220 - soldering position;
[0031] The component symbols in this application are explained as follows: 1000-cell battery; 100-electrode assembly; 110-electrode body; 120-first tab group; 121-first tab; 1211-widened portion; 12111-arc-wall; 1212-main body; 12121-centerline; 12122-first sidewall; 12123-second sidewall; 12124-arc-bevel; 130-second tab group; 131-second tab; 200-connecting piece; 210-soldering mark; 300-protective piece; 400-casing; 500-cover plate; 2000-welding position; X-first direction; Y-second direction; Z-third direction. Detailed Implementation
[0032] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.
[0033] In the description of this application, the terms "center", "longitudinal", "lateral", "length", "width", "height", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.
[0034] Furthermore, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Moreover, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0035] In the description of this application, the terms "first," "second," etc., are used to distinguish different objects and should not be construed as indicating or implying a specific order or hierarchy, or implicitly specifying the number of technical features indicated. Therefore, a feature marked "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly defined.
[0036] In the description of this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0037] In the description of this application, the term "and / or" indicates that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " generally indicates that the preceding and following objects have an "or" relationship.
[0038] In the description of this application, "parallel" includes not only the case of absolute parallelism, but also the case of approximate parallelism as commonly understood in engineering; similarly, "perpendicular" also includes not only the case of absolute perpendicularity, but also the case of approximate perpendicularity as commonly understood in engineering. For example, if the angle between two directions is 80° to 90°, the two directions can be considered perpendicular; if the angle between two directions is 0° to 10°, the two directions can be considered parallel.
[0039] The fabrication of electrode assemblies in a single battery cell typically involves two processes: lamination and winding. After lamination or winding, the tabs in the electrode assembly need to be welded to the connecting tabs of the terminal posts to achieve electrical connection between the terminal posts and the electrode assembly. However, as... Figure 1 and Figure 2 As shown, in existing electrode assemblies, the tab group 210 includes multiple tabs 211 stacked together. After stacking or winding, due to differences in the thickness of the electrode sheet and the diaphragm of the electrode body or errors in the cutting of the electrode sheet, adjacent tabs 211 may be misaligned. This can lead to some tabs 211 being deviated from the welding position 220 and causing welding abnormalities when ultrasonically welding the tab group 210 to the connecting piece.
[0040] like Figure 3 and Figure 4As shown, in order to solve the above-mentioned technical problems, embodiments of this application provide a battery cell 1000, which relates to the field of battery technology and is mainly used in battery packs, so as to be indirectly applied to electrical devices or energy storage devices in the form of battery packs. Of course, the battery cell 1000 can also be directly applied to electrical devices or energy storage devices without taking the form of battery packs, and no specific limitation is made to the application scenarios of the battery cell 1000 here.
[0041] For example, electrical devices can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools. Vehicles can be gasoline-powered cars, natural gas-powered cars, new energy vehicles, etc., and new energy vehicles can be pure electric vehicles, hybrid electric vehicles, and range-extended electric vehicles, etc.; spacecraft can be airplanes, rockets, space shuttles, drones, and spacecraft, etc.; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.; power tools can be metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.; energy storage devices include energy storage containers, energy storage power stations, etc.; no specific limitations are made on the types of electrical devices and energy storage devices here.
[0042] Combination Figures 5 to 7 As shown, the battery cell 1000 provided in this embodiment has a first direction X and a third direction Z that are perpendicular to each other, and includes: an electrode assembly 100 and a connecting piece 200.
[0043] The electrode assembly 100 includes an electrode body 110, a first tab group 120, and a second tab group 130. The first tab group 120 and the second tab group 130 are spaced apart along a first direction X. The first tab group 120 includes a plurality of first tabs 121 stacked along a third direction Z. The second tab group 130 includes a plurality of second tabs 131 stacked along a third direction Z. The first tabs 121 and the second tabs 131 are respectively connected to the electrode body 110. A connecting piece 200 is welded to the first tab 121 to form a solder mark 210 on the connecting piece 200. The solder mark 210 is located inside the first tab 121. The first tab 121 has arc-shaped walls 12111 that bend away from the solder mark 210 on both sides along the first direction X.
[0044] It should be noted that "the solder mark 210 is located inside the first tab 121" can be understood as: when projected onto a plane perpendicular to the third direction Z, the orthographic projection of the solder mark 210 is located inside the orthographic projection of the first tab 121.
[0045] Furthermore, during the fabrication of the battery cell 1000, the connecting piece 200 is welded to the terminal post passing through the cover plate 500. After the first tab 121 and the second tab 131 are welded to the connecting piece 200, the electrode assembly 100 needs to be assembled so that the electrode assembly 100 can be installed into the housing 400. After the electrode assembly 100 is installed in the housing, the cover plate 500 is welded to the housing 400 to seal it. During the assembly of the electrode assembly 100, the first tab 121 and the second tab 131 will bend as the assembly is completed, and the bent parts are welded to the connecting piece 200. Therefore, "the first tab group 120 includes a plurality of first tabs 121 stacked along the third direction Z" means that the bent parts of the plurality of first tabs 121 are stacked along the third direction Z; similarly, "the second tab group 130 includes a plurality of second tabs 131 stacked along the third direction Z" means that the bent parts of the plurality of second tabs 131 are stacked along the third direction Z.
[0046] It is understood that in the battery cell 1000 provided in this embodiment, the connecting piece 200 is welded to the first tab 121 to form a solder mark 210 on the connecting piece 200. Each first tab 121 is provided with an arc-shaped wall 12111 that bends away from the solder mark 210 on both sides along the first direction X. The arc-shaped wall 12111 increases the size of each first tab 121 that can be ultrasonically welded in the first direction X, thereby improving the situation where the tab deviates from the welding position 2000 and causing welding abnormalities, and improving the yield of ultrasonic welding between the tab assembly and the connecting piece 200.
[0047] like Figure 3 , Figure 6 and Figure 7 As shown, in one embodiment, the battery cell 1000 has a second direction Y perpendicular to the first direction X and the third direction Z (i.e., the first direction X, the second direction Y, and the third direction Z are mutually perpendicular). The first electrode 121 has a centerline 12121 parallel to the second direction Y. The first electrode 121 includes a main body 1212 and a plurality of widening portions 1211 disposed opposite to each other along the first direction X. The main body 1212 is connected between two adjacent widening portions 1211. The size of each widening portion 1211 along the first direction X is smaller than the size of the main body 1212 along the first direction X. A portion of the solder mark 210 is located inside the widening portion 1211. The widening portion 1211 protrudes in a direction away from the centerline 12121. The arcuate wall 12111 is located at the edge of the widening portion 1211.
[0048] It should be noted that "a portion of the solder mark 210 is located within the widened portion 1211" can be understood as: when projected onto a plane perpendicular to the third direction Z, the orthographic projection of the solder mark 210 and the orthographic projection of the first tab 121 coincide.
[0049] Understandably, by setting the widening portion 1211, the size of each first electrode tab 121 that can be ultrasonically welded in the first direction X is further increased, thereby more effectively improving the situation where welding abnormalities are caused by the electrode tab deviating from the welding position 2000.
[0050] like Figure 6 and Figure 7 As shown, further, a portion of the solder mark 210 is located within the main body 1212. The main body 1212 has a first sidewall 12122 and a second sidewall 12123 spaced apart. The first sidewall 12122 is connected to the electrode body 110. The arc-shaped wall 12111 is smoothly connected to the first sidewall 12122 and the second sidewall 12123 respectively. This can improve the situation of sharp edges and corners, reduce the abnormal phenomenon of folding and wrinkling when the first tab 121 passes through the roller, and improve the production yield of the battery cell 1000.
[0051] It should be noted that "a portion of the solder mark 210 is located within the main body 1212" can be understood as: when projected onto a plane perpendicular to the third direction Z, the orthographic projection of the solder mark 210 and the orthographic projection of the main body 1212 coincide.
[0052] like Figure 6 As shown, the main body 1212 further has an arc-shaped chamfer 12124 that bends away from the main body 1212. The arc-shaped chamfer 12124 is connected to the arc-shaped wall 12111 and the second side wall 12123 respectively, so as to achieve a smooth transition connection between the arc-shaped wall 12111 and the second side wall 12123, thereby reducing the abnormal phenomenon of folding and wrinkling that occurs when the first electrode ear 121 passes through the roller.
[0053] Of course, in the above embodiment, the arc-shaped chamfer 12124 can also be connected to the arc-shaped wall 12111 and the first side wall 12122 respectively, so as to achieve a smooth transition connection between the arc-shaped wall 12111 and the first side wall 12122. In addition, the implementation of the smooth transition connection is not limited to setting the arc-shaped chamfer 12124, but can also be an S-shaped surface, a U-shaped surface, etc., and no specific limitation is made here.
[0054] For example, the dimension of the second sidewall 12123 along the first direction X is less than or equal to the dimension of the first sidewall 12122 along the first direction X. Of course, the dimension of the second sidewall 12123 along the first direction X may also be greater than the dimension of the first sidewall 12122 along the first direction X. Here, no specific limitation is made on the dimensions of the first sidewall 12122 and the second sidewall 12123 along the first direction X.
[0055] like Figure 3 and Figure 7As shown, in one embodiment, the battery cell 1000 further includes a protective sheet 300. The protective sheet 300 is located on the side of the first tab assembly 120 away from the connecting piece 200 along the third direction Z, and is connected to the first tab 121. The material of the protective sheet 300 is the same as that of the first tab 121. It can be understood that by providing the protective sheet 300, the weld thickness between the first tab assembly 120 and the protective sheet 300 can be increased, and the possibility of the first tab assembly 120 being burned through during welding can be reduced, thereby improving the production yield of the battery cell 1000.
[0056] Furthermore, the battery cell 1000 also includes an insulating layer connected to the side of the protective sheet 300 away from the connecting sheet 200 along the third direction Z. This reduces the safety risk of a short circuit caused by the protective sheet 300 contacting the electrode body 110 along the third direction Z.
[0057] Furthermore, the insulation layer and the protective sheet 300 are integrally formed, that is, the insulation layer and the protective sheet 300 are manufactured by an integral molding process. This can increase the stability of the insulation layer and the protective sheet 300, thereby reducing the risk of poor welding and short circuit.
[0058] For example, integral molding processes include injection molding, die casting, extrusion molding, 3D printing, etc., without specific limitations.
[0059] like Figure 3 As shown, in one embodiment, the battery cell 1000 has a second direction Y perpendicular to both the first direction X and the third direction Z (i.e., the first direction X, the second direction Y, and the third direction Z are mutually perpendicular). The electrode body 110 includes a first electrode, a second electrode, and a separator, with the separator disposed between the first and second electrodes. A first tab 121 is connected to the first electrode, and a second tab 131 is connected to the second electrode. The first electrode, the second electrode, and the separator are wound together to form the electrode body 110, or the first electrode, the second electrode, and the separator are stacked along the second direction Y to form the electrode body 110. That is, the design of the arc-shaped wall 12111 is applicable not only to electrode assemblies 100 manufactured using a winding process but also to electrode assemblies 100 manufactured using a stacking process. No specific limitations are made here regarding the application scope of the arc-shaped wall 12111.
[0060] It should be noted that the second electrode 131 can also adopt the design of the arc-shaped wall 12111, thereby increasing the size of each second electrode 131 that can be ultrasonically welded in the first direction X, which will not be elaborated here.
[0061] It should be noted that the battery cell 1000 provided in this embodiment mainly relies on the movement of metal ions between the positive and negative electrode plates to operate. The battery cell 1000 can be cuboid, cylindrical, flat, or other shapes, and is not specifically limited here. According to the packaging method, the battery cell 1000 provided in this embodiment can be a square battery cell, a cylindrical battery cell, a pouch battery cell, etc., and is not specifically limited here.
[0062] Furthermore, according to the classification of the physical state of the electrolyte, the battery cell 1000 provided in this embodiment can be a liquid battery, that is, it uses a liquid electrolyte. Exemplarily, the terminals passing through the cover plate 500 include a positive terminal and a negative terminal. One of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode. One of the first tab 121 and the second tab 131 is a positive tab, and the other is a negative tab. The separator material can be PP (polypropylene), PE (polyethylene), etc. The positive electrode includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector. The positive tab is connected to the positive current collector and is electrically connected to the positive terminal through a connecting piece 200. The negative electrode includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector. The negative tab is connected to the negative current collector and is electrically connected to the negative terminal through another connecting piece 200. Taking lithium ions as an example, the materials for the positive electrode current collector and the positive electrode tab can be aluminum, and the materials for the positive electrode active material layer can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, lithium manganese oxide, etc.; the materials for the negative electrode current collector and the negative electrode tab can be copper, and the negative electrode active material can be graphite, silicon, etc.
[0063] Of course, the battery cell 1000 provided in this embodiment can also be a solid-state battery, that is, it uses a solid electrolyte, such as sulfide, oxide or polymer electrolytes. Solid electrolytes can replace separators and liquid electrolytes, and have both ion conduction and isolation functions. The type of battery cell 1000 is not specifically limited here. In order to solve the above technical problems, the embodiments of this application also provide a battery pack, including the battery cell 1000 in any of the above embodiments.
[0064] It is understood that since the battery pack provided in this embodiment has the battery cell 1000 in any of the above embodiments, it has all the beneficial effects of the battery cell 1000, which will not be described in detail here.
[0065] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0066] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.
Claims
1. A battery cell, characterized in that, Having a first perpendicular direction (X) and a third perpendicular direction (Z), the battery cell comprises: The electrode assembly (100) includes an electrode body (110), a first tab group (120), and a second tab group (130). The first tab group (120) and the second tab group (130) are spaced apart along the first direction (X). The first tab group (120) includes a plurality of first tabs (121) stacked along the third direction (Z). The second tab group (130) includes a plurality of second tabs (131) stacked along the third direction (Z). The first tabs (121) and the second tabs (131) are respectively connected to the electrode body (110). A connecting piece (200) is welded to the first electrode tab (121) to form a solder mark (210) on the connecting piece (200). The solder mark (210) is located inside the first electrode tab (121). The first electrode tab (121) is provided with arc-shaped walls (12111) on both sides along the first direction (X) that bend away from the solder mark (210).
2. The battery cell according to claim 1, characterized in that, The battery cell has a second direction (Y) perpendicular to the first direction (X) and the third direction (Z). The first tab (121) has a centerline (12121) parallel to the second direction (Y). The first tab (121) includes a main body (1212) and a plurality of widening portions (1211) disposed opposite to each other along the first direction (X). The main body (1212) is connected between two adjacent widening portions (1211). The size of each widening portion (1211) along the first direction (X) is smaller than the size of the main body (1212) along the first direction (X). A portion of the solder mark (210) is located inside the widening portion (1211). The widening portion (1211) protrudes in a direction away from the centerline (12121). The arc-shaped wall (12111) is located at the edge of the widening portion (1211).
3. The battery cell according to claim 2, characterized in that, A portion of the solder mark (210) is located within the main body (1212), which has a first sidewall (12122) and a second sidewall (12123) spaced apart. The first sidewall (12122) is connected to the electrode body (110), and the arc-shaped wall (12111) is smoothly connected to the first sidewall (12122) and the second sidewall (12123).
4. The battery cell according to claim 3, characterized in that, The main body (1212) has an arc-shaped chamfer (12124) that bends away from the main body (1212), and the arc-shaped chamfer (12124) is connected to the arc-shaped wall (12111) and the second side wall (12123) respectively.
5. The battery cell according to claim 3, characterized in that, The dimension of the second sidewall (12123) along the first direction (X) is less than or equal to the dimension of the first sidewall (12122) along the first direction (X).
6. The battery cell according to any one of claims 1 to 5, characterized in that, The battery cell also includes a protective sheet (300), which is located on the side of the first tab group (120) away from the connecting piece (200) along the third direction (Z) and is connected to the first tab (121). The material of the protective sheet (300) is the same as that of the first tab (121).
7. The battery cell according to claim 6, characterized in that, The battery cell also includes an insulating layer connected to the protective sheet (300) on the side away from the connecting sheet (200) along the third direction (Z).
8. The battery cell according to claim 7, characterized in that, The insulating layer is integrally formed with the protective sheet (300).
9. The battery cell according to any one of claims 1 to 5, characterized in that, The battery cell has a second direction (Y) perpendicular to the first direction (X) and the third direction (Z). The electrode body (110) includes a first electrode, a second electrode, and a separator. The separator is disposed between the first electrode and the second electrode. The first tab (121) is connected to the first electrode, and the second tab (131) is connected to the second electrode. The first electrode, the second electrode, and the separator are wound together to form the electrode body (110), or the first electrode, the second electrode, and the separator are stacked along the second direction (Y) to form the electrode body (110).
10. A battery pack, characterized in that, Includes the battery cell according to any one of claims 1 to 9.