Winding battery cell, battery and electric equipment
By setting markers and pole ear units in the winding battery cell, the problems of missing and misjudgment caused by pole ear position deviation are solved, and higher detection accuracy and improved pass rate of the winding battery cell are achieved.
Patent Information
- Application Number
- CN202422355436.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2025-08-22
- Estimated Expiration
- 2034-09-26
AI Technical Summary
In the prior art, the position deviation of the electrode position of the multi-pole ear winding battery cell depends on manual visual inspection, which has the possibility of misjudgment and wrong judgment, which affects the subsequent process and may lead to damage to the electrode, reducing the production advantage.
The marker and the pole ear unit are arranged in the winding battery cell. The alignment of the marker and the pole ear is determined whether the pole ear position is offset, and the pole sheet insertion point is adjusted to ensure the accuracy of the pole ear position and reduce the possibility of leakage and error judgment.
It improves the accuracy and reliability of manual inspection, reduces the possibility of polar ear position offset, and improves the pass rate and production efficiency of the winding battery cell.
Smart Images
Figure CN223260627U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of battery technology, and in particular to wound battery cells, batteries and electrical equipment. Background Art
[0002] With the development of battery technology, multi-tab wound battery cell technology has emerged. Multi-tab wound battery cells can reduce battery impedance, improve battery performance, and are simple to prepare and have high production efficiency.
[0003] Typically, a wound battery cell is formed by winding a stack of positive and negative electrode sheets, along with a separator, in a predetermined direction. When the positive electrode sheet is coated, an empty foil area is left at the edge of the current collector, which is then die-cut to form multiple positive electrode tabs. Similarly, when the negative electrode sheet is coated, an empty foil area is left at the edge of the current collector, which is then die-cut to form multiple negative electrode tabs. However, during the winding process, the position of the tabs in the core is primarily determined by the position of the first tab, i.e., the positive and negative electrode entry positions. If the insertion position of the tab (i.e., the insertion point of the tab) fluctuates, all tabs will shift as a whole. If the position shift exceeds the range, it will affect processes such as welding, gluing, and shell insertion, and may even cause the core to be scrapped, affecting the manufacturing yield.
[0004] In related technologies, the position deviation of the tab mainly relies on manual visual inspection, which may cause missed judgment or wrong judgment, resulting in the risk of tab welding failure in subsequent processes, and easily causing damage to the tab, seriously affecting the status of the tab. Utility Model Content
[0005] Based on this, it is necessary to provide a wound battery cell, battery and electrical equipment to address the above technical problems, so as to improve the accuracy of manual detection and reduce the possibility of missed judgment and wrong judgment.
[0006] In the first aspect, the present application provides a wound battery cell, which is formed by winding a positive electrode sheet and a negative electrode sheet along a preset direction and has a central axis in the thickness direction, at least one of the positive electrode sheet and the negative electrode sheet includes: a electrode body, the electrode body includes a first end and a second end, the second end is configured to be wound relative to the first end along the central axis direction; and a tab group, the tab group includes a marking member and a tab unit, the marking member and the tab unit are connected to the same end face of the electrode body, the tab unit includes a first tab, the marking member is arranged at the first end and the marking member and the first tab are arranged on both sides of the central axis, and the midline of the marking member in the direction of the central axis can be aligned with the midline of the first tab in the direction of the central axis.
[0007] The wound cell is constructed by placing the marking member on one side of the central axis and the first tab on the other side of the central axis. This arrangement allows the alignment of the center line of the marking member along the central axis with the center line of the first tab during actual winding to determine whether the tab unit is shifted within the wound cell.
[0008] Specifically, when the midline of the marking member in the direction of the central axis is aligned with the midline of the first pole lug in the direction of the central axis, the pole lug unit has not been offset and winding can continue; when the midline of the marking member in the direction of the central axis is not aligned with the midline of the first pole lug in the direction of the central axis, position offset will occur if the pole lug unit continues to be wound. At this time, the position of the first end (i.e., the position of the insertion point of the pole piece on the winding needle) can be adjusted according to the offset between the marking member and the midline of the first pole lug in the direction of the central axis, so that the midline of the first pole lug in the direction of the central axis is aligned with the midline of the marking member in the direction of the central axis, and then winding can be continued to reduce the possibility of pole lug position offset in the pole lug unit.
[0009] The relative position of the marking part and the first tab can be used to determine whether the tab unit will be positionally offset, thereby improving the accuracy and reliability of manual inspection, reducing the possibility of missed and wrong judgments, and timely changing the position of the first end to improve the qualified rate of the wound battery cell.
[0010] In one embodiment, the tab unit further includes a plurality of second tabs, and the plurality of second tabs and the first tab are arranged in sequence along the thickness direction of the wound battery cell, and the midlines of the plurality of second tabs in the direction of the central axis can be aligned with the midline of the first tab in the direction of the central axis.
[0011] In one embodiment, the first electrode tab and the plurality of second electrode tabs have the same size in the direction of the central axis, and in the thickness direction, the spacing between two adjacent second electrode tabs gradually increases and is greater than the spacing between adjacent first electrode tabs and second electrode tabs.
[0012] In one embodiment, the dimension of the marking member in the direction of the central axis is smaller than or equal to the dimension of the first electrode tab in the direction of the central axis.
[0013] In one embodiment, the size of the marking member in the direction of the central axis ranges from 10 mm to 50 mm.
[0014] In one embodiment, the shape of the marking element is the same as the shape of the first tab.
[0015] In one embodiment, the marking element and the first tab are both trapezoidal in shape.
[0016] In one embodiment, the positive electrode sheet and the negative electrode sheet each independently include a sheet body and a tab group having a marking member and a tab unit, and the tab group of the positive electrode sheet and the tab group of the negative electrode sheet have opposite polarities.
[0017] In a second aspect, the present application provides a battery comprising the wound battery cell as described above.
[0018] In a third aspect, the present application provides an electrical device, which includes the wound battery cell or the battery as described above. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 Schematic diagram of a wound battery cell in one embodiment of the present application.
[0020] Figure 2 Schematic diagram of a pole piece in one embodiment of the present application.
[0021] Explanation of the accompanying reference numerals: 100, wound battery cell; 10, pole piece; 11, pole piece body; 111, first end; 112, second end; 121, marking member; 122, pole tab unit; 1221, first pole tab; 1222, second pole tab; Z, thickness direction; O, center axis. DETAILED DESCRIPTION
[0022] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.
[0023] In the description of this application, it should be understood that if the 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. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.
[0024] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.
[0025] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.
[0026] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.
[0027] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.
[0028] See Figure 1 and Figure 2 , Figure 1 1 shows a schematic diagram of a wound battery cell 100 in an embodiment of the present application. Figure 2 A cross-sectional view of a wound battery cell 100 in one embodiment of the present application is shown.
[0029] The wound battery cell 100 is formed by winding an electrode sheet 10 along a predetermined direction. Typically, the wound battery cell 100 includes a positive electrode sheet and a negative electrode sheet, which are wound along a predetermined direction to form the wound battery cell 100. In an embodiment not shown, the wound battery cell 100 further includes a separator positioned between the positive and negative electrode sheets. The separator is used to prevent direct contact between the positive and negative electrode sheets, thereby preventing a short circuit in the wound battery cell 100.
[0030] The wound cell 100 can be formed into different shapes according to actual needs, such as cylindrical, square, soft-pack, etc. Its specific shape depends on the application requirements and is not specifically limited here. In the drawings of the description of the embodiments of this application, a square wound cell 100 is used as an example.
[0031] The wound battery cell 100 has a central axis O in the thickness direction Z. The central axis O refers to the median line that divides the innermost circumference of the wound battery cell 100 into two equal parts. That is, in the thickness direction Z, all points on the central axis O are equidistant from the two sides of the innermost circumference of the wound battery cell 100.
[0032] At least one of the positive and negative electrode sheets includes a sheet body 11 and a tab assembly. The sheet body 11 is the main portion of the battery sheet 10. The sheet body 11 includes a first end 111 and a second end 112. The first end 111 is configured as an insertion end, and the second end 112 is configured to be wound relative to the first end 111 in a predetermined direction. Specifically, the first end 111 is the starting end of the sheet body 11, and the second end 112 is the ending end of the sheet body 11.
[0033] The tab assembly includes a marking member 121 and a tab unit 122, which are connected to the same end face of the pole piece body 11. The marking member 121 is provided at the first end 111, and the marking member 121 is arranged on one side of the central axis O in the thickness direction Z, and the tab unit 122 is arranged on the other side of the central axis O in the thickness direction Z.
[0034] Both the marking member 121 and the tab unit 122 are used to output current to an external circuit. Typically, to increase the number of connection points or contact area for current output on the electrode 10 and improve the battery's charge and discharge performance, the tab unit 122 includes multiple tabs. This allows current to be output from multiple tabs simultaneously to the external circuit, effectively improving current transmission capacity and uniformity while reducing the risk of current density and heat concentration.
[0035] It should be noted that because the structures of the negative electrode sheets in the drawings of this application are substantially identical to those of the positive electrode sheets, each independently comprises a sheet body and a tab assembly having a marking member and a tab unit, and the polarity of the tab assembly of the positive electrode sheet and the tab assembly of the negative electrode sheet are opposite. For ease of description, the reference numerals in this application are described in detail using the positive electrode sheet as an example.
[0036] In other embodiments not shown in the figures, the specific structure of the negative electrode plate and the specific structure of the positive electrode plate may also be different, such as the positive electrode plate includes a plate body and a tab group having a marking part and a tab unit, and the negative electrode plate only includes a tab unit and a tab group having a tab unit; or the positive electrode plate only includes a plate body and a tab group having a tab unit, and the negative electrode plate includes a tab unit and a tab group having a marking part and a tab unit.
[0037] Marking member 121 is used to determine whether the position of tab unit 122 in wound cell 100 has shifted, thereby improving the accuracy of manual inspection. Specifically, tab unit 122 also includes a first tab 1221. First tab 1221 and marking member 121 are located on either side of central axis O. The centerline of first tab 1221 along central axis O coincides with the centerline of marking member 121 along central axis O (i.e., the centers of first tab 1221 and marking member 121 are aligned along central axis O).
[0038] By placing the marking member 121 on one side of the central axis O and the first tab 1221 on the other side of the central axis O, with the midline of the first tab 1221 in the direction of the central axis O coinciding with the midline of the marking member 121 in the direction of the central axis O coinciding with the midline of the marking member 121 in the direction of the central axis O , it is possible to determine whether the position of the tab unit 122 in the wound cell 100 has shifted by aligning the midline of the marking member 121 in the direction of the central axis O with the midline of the first tab 1221 in the direction of the central axis O . Furthermore, by measuring the distance between the midline of the first tab 1221 in the direction of the central axis O and the midline of the marking member 121 in the direction of the central axis O , the insertion point of the winding needle during the winding of the electrode sheet can be adjusted, thereby adjusting the position of the tab unit 122 in the wound cell 100 so that the position of the tab unit 122 in the wound cell 100 remains the same as the preset position of the tab unit 122.
[0039] Specifically, during the actual winding process, when the midline of the marking member 121 in the direction of the central axis 0 is aligned with the midline of the first pole lug 1221 in the direction of the central axis 0, the pole lug unit 122 has not been offset and the winding can continue; when the midline of the marking member 121 in the direction of the central axis 0 is not aligned with the midline of the first pole lug 1221 in the direction of the central axis 0, if the pole lug unit 122 continues to be wound, the pole lug position will be offset. At this time, the position of the first end 111 (that is, the position of the insertion point of the pole piece on the winding needle) can be adjusted according to the offset between the midline of the marking member 121 and the first pole lug 1221 in the direction of the central axis 0, so that the midline of the first pole lug 1221 in the direction of the central axis 0 is aligned with the midline of the marking member 121 in the direction of the central axis 0, and then the winding can be continued to reduce the possibility of pole lug position offset in the pole lug unit 122.
[0040] More specifically, Figure 1 For example, when the wound battery cell 100 is wound clockwise, in the actual winding process, the midline of the marking part 121 in the direction of the central axis 0 is named the first midline, and the midline of the first pole ear 1221 in the direction of the central axis 0 is named the second midline; if the first midline and the second midline do not coincide in the actual winding, it can be explained that the pole ear unit 122 has been offset during the winding process, that is, the insertion point of the pole piece 10 on the winding needle has deviated.
[0041] By setting the marking member 121, Figure 1 In the illustrated direction, if the first median line is offset to the left relative to the second median line, that is, the insertion point of the pole piece 10 is actually offset to the right, then the insertion point of the pole piece 10 should be adjusted at this time, and the adjustment amount of the insertion point is the distance between the first median line and the second median line.
[0042] The relative position of the first midline of the marking member 121 and the second midline of the first tab 1221 can be used to determine whether the tab unit 122 is misaligned, thereby improving the accuracy and reliability of manual inspections, reducing the possibility of missed or misjudgment, and allowing for timely adjustment of the position of the first end 111 (i.e., adjusting the electrode insertion point), thereby improving the pass rate of the wound battery cell 100. In some embodiments, the tab unit 122 further includes a plurality of second tabs 1222, with the first tab 1221 and the plurality of second tabs 1222 being arranged sequentially along the thickness direction Z. The midlines of the first tab 1221 and the plurality of second tabs 1222 along the central axis O can be aligned in the thickness direction Z.
[0043] By aligning the midline of the marking part 121 in the direction of the central axis O with the midline of the first pole lug 1221 in the direction of the central axis O, the midlines of the multiple second pole lugs 1222 in the direction of the central axis O will also be aligned with the midline of the first pole lug 1221 in the direction of the central axis O. At this time, the first pole lug 1221 and the second pole lug 1222 of the pole lug unit 122 are in an aligned state in the thickness direction Z, and the wound battery cell 100 has good safety performance and processing performance.
[0044] In a possible embodiment, combined with Figure 1 and Figure 2 The first pole tab 1221 and the plurality of second pole tabs 1222 have the same size in the direction of the central axis O, and the distance between two adjacent second pole tabs on the pole piece 10 gradually increases.
[0045] The first pole tab 1221 and the plurality of second pole tabs 1222 have the same size. As the second end 112 is wound along a predetermined direction, the second pole tab 1222 located on the outside needs to have a larger stroke to align with the second pole tab 1222 located on the inside. That is, as the number of winding layers increases, the spacing between adjacent second pole tabs 1222 gradually increases. By changing the spacing between adjacent second pole tabs 1222, the plurality of second pole tabs 1222 can be aligned in the thickness direction Z.
[0046] In another feasible embodiment, the sizes of the first electrode tab 1221 and the plurality of second electrode tabs 1222 in the direction of the central axis O may be different. For example, the sizes of the plurality of second electrode tabs 1222 in the direction of the central axis O may gradually increase or decrease along the thickness direction Z compared to the sizes of the first electrode tab 1221 in the direction of the central axis O.
[0047] Furthermore, the shape of the marking member 121 is the same as that of the first electrode tab 1221 and the second electrode tab 1222 , so that the marking member 121 and the electrode tab unit 122 can be prepared by the same die-cutting equipment, thereby improving the production efficiency of the wound battery cell 100 .
[0048] Optionally, the marking member 121, the first pole ear 1221, and the second pole ear 1222 are narrow at the top and wide at the bottom, that is, the dimensions of the marking member 121, the first pole ear 1221, and the second pole ear 1222 on the side connected to the pole piece body 11 are larger than the dimensions on the side away from the pole piece body 11.
[0049] On the one hand, the shape of being narrow at the top and wide at the bottom can prevent the connection part between the tab group and the pole piece body 11 from being too sharp, thereby reducing the risk of the isolation membrane being punctured. On the other hand, it can also increase the width of the connection part between the tab group and the pole piece body 11, thereby preventing the connection part from breaking or unnecessary deformation during the winding process, thereby improving the production quality of the wound battery cell 100.
[0050] Optionally, the shapes of the marking member 121, the first pole tab 1221, and the second pole tab 1222 are all trapezoidal. The trapezoidal setting makes it easier to judge the alignment of the marking member 121, the first pole tab 1221, and the plurality of second pole tabs 1222, improves the accuracy of manual inspection, and facilitates the adjustment and correction of the position of the first end 111 during the winding process. Furthermore, the trapezoidal setting helps to reduce stress concentration in the pole tab unit 122, avoid damage to the pole tab unit 122 during the winding process, and improve the stability and reliability of the wound battery cell 100. Preferably, the shapes of the marking member 121, the first pole tab 1221, and the plurality of second pole tabs 1222 are isosceles trapezoids.
[0051] The corners of the trapezoid are all arc-shaped. The arc-shaped arrangement helps reduce stress concentration in the first electrode tab 1221 and the plurality of second electrode tabs 1222, facilitates current transmission, and helps reduce collision damage to the first electrode tab 1221 and the plurality of second electrode tabs 1222 during subsequent assembly. Optionally, the base angle of the trapezoid is 0-90°.
[0052] In an embodiment not shown, the connection between the marking member 121 and the pole piece body 11, and the pole tab unit 122 and the pole piece body 11, is also configured in an arc shape. The arc shape can make the transition between the marking member 121 and the pole piece body 11, and the connection between the pole tab unit 122 and the pole piece body 11 more natural and smooth, reducing the local concentration of current and the conduction problems at the connection between the pole tab unit 122 and the pole piece body 11. This can improve the charge and discharge performance of the battery while avoiding a significant reduction in the energy density of the battery, thus achieving a balance between the two.
[0053] It should be noted that the shape of the marking member 121, the first pole tab 1221 and the multiple second pole tabs 1222 being narrow at the top and wide at the bottom is only a preferred embodiment. This application does not limit the shape of the marking member 121, the first pole tab 1221 and the multiple second pole tabs 1222. The shape of the marking member 121, the first pole tab 1221 and the multiple second pole tabs 1222 can also be square, triangular or irregular, etc.
[0054] In other feasible embodiments, the shape of the marking member 121 and the shape of the first tab 1221 may also be different, thereby making it easier to identify the marking member 121 and improving the efficiency of manual inspection.
[0055] Furthermore, the size of the marking member 121 in the direction of the central axis O is less than or equal to the size of the first tab 1221 in the direction of the central axis O, thereby facilitating the determination of whether the midline of the marking member 121 in the direction of the central axis O and the midline of the first tab 1221 in the direction of the central axis O are aligned, facilitating manual determination of the positional offset of the tab unit 122 and improving the accuracy and efficiency of detection. Optionally, the size of the marking member 121 in the direction of the central axis O ranges from 10 mm to 50 mm.
[0056] Preferably, the size of the marking member 121 in the direction of the central axis O is equal to the size of the first pole tab 1221 in the direction of the central axis O, and the shape of the marking member 121 is the same as the shape of the first pole tab 1221. As a result, the marking member 121, the first pole tab 1221, and the plurality of second pole tabs 1222 can be processed using the same die-cutting mold, thereby improving the production efficiency of the wound battery cell 100. Because the size of the marking member 121 in the direction of the central axis O is equal to the size of the first pole tab 1221 in the direction of the central axis O, by determining whether the two ends of the marking member 121 and the first pole tab 1221 in the direction of the central axis O are aligned, it can be determined whether the midline of the marking member 121 in the direction of the central axis O is aligned with the midline of the first pole tab 1221 in the direction of the central axis O, which helps to improve the efficiency and accuracy of manual identification.
[0057] By measuring the offset of the ends of the marking member 121 and the first pole tab 1221 in the direction of the central axis 0, the distance between the center line of the first pole tab 1221 in the direction of the central axis 0 and the center line of the marking member 121 in the direction of the central axis 0 can be obtained, thereby improving measurement efficiency and measurement accuracy.
[0058] In the above-described embodiment, the wound battery cell 100 can determine whether the tab unit 122 is offset by the position of the marking member 121 relative to the first tab 1221, thereby improving the accuracy and reliability of manual inspection. Furthermore, the positioning of the marking member 121 at the first end 111 allows for more effective tabs to be provided on the wound electrode sheet 10, thereby improving the utilization rate of the electrode sheet 10. Furthermore, the offset between the marking member 121 and the midline of the first tab 1221 in the direction of the central axis O allows for timely and effective adjustment of the position of the first end 111, thereby improving material utilization and the rationality of the wound battery cell 100, thereby reducing material and production costs.
[0059] In addition, the present application also provides a battery. Specifically, the wound battery cell 100 of the above embodiment can be placed in a housing of suitable size. After steps such as providing connecting components for transmitting electrical energy and injecting electrolyte, a battery with the ability to store and release electrical energy is produced.
[0060] Alternatively, the outer shell may be a packaging bag encapsulated with an encapsulating film, that is, the wound battery cell 100 may be a soft-pack battery cell. In other embodiments, the wound battery cell 100 may also be a steel shell battery cell or an aluminum shell battery cell, etc., which is not limited in this application.
[0061] In addition, the present application also provides an electrical device, which includes the battery provided herein. The battery can serve as a power source for the electrical device or as an energy storage unit for the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships, satellites, energy storage systems, etc.
[0062] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0063] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.
Claims
1. A wound battery cell, characterized in that: The wound battery cell is formed by winding a positive electrode sheet and a negative electrode sheet along a preset direction, and the wound battery cell has a central axis in the thickness direction, and at least one of the positive electrode sheet and the negative electrode sheet includes: a pole piece body, the pole piece body comprising a first end and a second end, the second end being configured to be wound relative to the first end along the preset direction; and A tab group, the tab group includes a marking member and a tab unit, the marking member and the tab unit are connected to the same end face of the pole piece body, the tab unit includes a first tab, the marking member is arranged at the first end, and the marking member and the first tab are arranged on both sides of the central axis, and the midline of the marking member in the direction of the central axis can be aligned with the midline of the first tab in the direction of the central axis.
2. The wound battery cell according to claim 1, characterized in that The tab unit also includes a plurality of second tabs, which are arranged in sequence with the first tab along the thickness direction of the wound battery cell, and the midlines of the plurality of second tabs in the direction of the central axis can be aligned with the midline of the first tab in the direction of the central axis.
3. The wound battery cell according to claim 2, characterized in that: The first electrode tab and the plurality of second electrode tabs have the same size in the direction of the central axis. In the thickness direction, the spacing between two adjacent second electrode tabs gradually increases and is greater than the spacing between adjacent first electrode tabs and second electrode tabs.
4. The wound battery cell according to claim 3, characterized in that: The dimension of the marking member in the direction of the central axis is smaller than or equal to the dimension of the first electrode tab in the direction of the central axis.
5. The wound battery cell according to claim 4, characterized in that: The size of the marking member in the direction of the central axis ranges from 10 mm to 50 mm.
6. The wound battery cell according to claim 1, characterized in that The shape of the marking member is the same as that of the first tab.
7. The wound battery cell according to claim 6, characterized in that: The marking member and the first tab are both trapezoidal in shape.
8. The wound battery cell according to claim 1, characterized in that: The positive electrode sheet and the negative electrode sheet each independently include a sheet body and a tab group having the marking member and the tab unit, and the tab group of the positive electrode sheet and the tab group of the negative electrode sheet have opposite polarities.
9. A battery, characterized in that: The battery comprises the wound battery cell according to any one of claims 1 to 8.
10. An electrical device, characterized in that: The electrical device comprises the wound battery cell according to any one of claims 1 to 8 or the battery according to claim 9.