Single battery and battery pack
By leading out tabs in the corner area of the electrode assembly and adopting a bent layer and slit structure, the problem of large space occupied by tabs is solved, the energy density and stability of the battery are improved, and higher foil utilization and current transmission uniformity are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-28
- Publication Date
- 2026-03-31
AI Technical Summary
Conventional square aluminum-cased batteries occupy a significant amount of internal space at the tab lead-out position, which affects the battery's energy density.
Design a single cell where the tabs are led out at the corner of the electrode assembly, and the tabs and the bent portions of the electrode sheets are stacked after winding. A slit structure and base connection are adopted to shorten the current path, reduce internal resistance, and improve structural stability.
It reduces the space occupied inside the battery, improves the battery's energy density and foil utilization, reduces internal resistance, and enhances the stability of the tabs and the uniformity of current transmission.
Smart Images
Figure CN224067853U_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of battery technology, specifically relating to a single cell battery and a battery pack. Background Technology
[0002] Lithium-ion power batteries have advantages such as small size, large capacity, high energy density, high charge and discharge rate, excellent low temperature performance, long service life and high safety.
[0003] In conventional square aluminum-cased batteries, the lead-out positions of the tabs occupy a significant amount of internal space when the electrodes are wound and assembled into the casing. Utility Model Content
[0004] The purpose of this utility model is to provide a single battery cell, which aims to overcome the technical problem that the current lead-out position of the electrode will occupy a lot of internal space of the battery; another purpose of this application is to provide a battery pack.
[0005] Technical solution: The single cell disclosed in the embodiments of this application has intersecting first and second directions, and the single cell includes an electrode assembly;
[0006] The electrode assembly includes a first electrode, a diaphragm, and a second electrode. The first electrode, the diaphragm, and the second electrode are stacked and wound together. The electrode assembly has a straight region, a first corner region, and a second corner region. The first corner region and the second corner region are respectively connected to opposite sides of the straight region in the first direction.
[0007] The electrode assembly further includes a first tab and a second tab, the first tab being connected to the first electrode plate and located in the first corner area, and the second tab being connected to the second electrode plate and located in the second corner area. The first tab and the second tab have opposite polarities and are located on the same side of the electrode assembly in the second direction.
[0008] In some embodiments, the first electrode includes a first corner segment, and the first corner segment is provided with a plurality of segments and stacked in the first corner region; the plurality of first corner segments are provided with the first electrode tab;
[0009] The second electrode includes a second corner segment, and multiple second corner segments are provided and stacked in the second corner area; the multiple second corner segments are provided with second electrode tabs.
[0010] In some embodiments, both the first electrode and the second electrode have an unfolding direction;
[0011] The first electrode tab includes a plurality of first bends, which are connected to the same first corner segment and are arranged along the unfolding direction of the first electrode sheet; when the electrode assembly is in a wound state, at least two first bends are bent and stacked in the second direction and electrically connected.
[0012] The second electrode tab includes a plurality of second bends, which are connected to the same second corner segment and are arranged along the unfolding direction of the second electrode sheet. When the electrode assembly is in a wound state, at least two second bends are bent and stacked in the second direction and electrically connected.
[0013] In some embodiments, both the first electrode tab and the second electrode tab are provided with multiple slits. The multiple slits on the first electrode tab are spaced apart along the unfolding direction of the first electrode sheet, and one slit is provided between two adjacent first bending portions.
[0014] The multiple slits on the second electrode tab are spaced apart along the unfolding direction of the second electrode sheet, and one of the slits is provided between two adjacent second bending portions.
[0015] In some embodiments, each first corner segment of a layer is provided with a first electrode tab, and two adjacent first bends on the first corner segments of the same layer are stacked in the second direction; or / and, the first bends on two adjacent first corner segments are stacked in the second direction;
[0016] Each second corner segment of each layer is provided with a second electrode tab, and two adjacent second bends on the second corner segments of the same layer are stacked in the second direction; or / and, the second bends of two adjacent second corner segments are stacked in the second direction.
[0017] In some embodiments, the first electrode further includes a first straight section, a third corner section, and a first electrodeless section. Multiple first straight sections are provided and stacked in the straight section. Multiple third corner sections are provided and stacked in the second corner section. Along the unfolding direction of the first electrode, the first straight section is connected between the first corner section and the third corner section. The first electrodeless section is located at the starting end of the winding of the first electrode. The first electrodeless section is connected to the first corner section, the first straight section, or the third corner section, and the first electrodeless section is wound at least two turns.
[0018] The second electrode further includes a second straight section, a fourth corner section, and a second electrodeless tab section. The second straight section has multiple sections and is stacked in the straight section. The fourth corner section has multiple sections and is stacked in the first corner section. Along the unfolding direction of the second electrode, the second straight section is connected between the second corner section and the fourth corner section. The second electrodeless tab section is located at the winding start end of the second electrode and is connected to the second corner section, the second straight section, or the fourth corner section. The second electrodeless tab section is wound at least two turns.
[0019] In some embodiments, the first electrode tab further includes a first base, the first base being connected between the first corner segment and the first bend, and the length of the first base and the corresponding first corner segment being equal in the unfolding direction of the first electrode sheet; or / and, at least two second bends are stacked and welded together.
[0020] The second electrode tab further includes a second base portion connected between the second corner segment and the second bend portion, and the length of the second base portion and the corresponding second corner segment are equal in the unfolding direction of the second electrode sheet; or / and, at least two second bend portions are stacked and welded.
[0021] In some embodiments, the single-cell battery further includes:
[0022] A housing having a receiving cavity;
[0023] A top cover assembly, the top cover assembly including a top cover plate, a first pole and a second pole, the top cover plate being connected to the housing and sealing the receiving cavity, the first pole and the second pole being disposed on the top cover plate, and at least one of the first pole and the second pole being insulated from the top cover plate;
[0024] The electrode assembly is disposed within the receiving cavity, and the first electrode tab is electrically connected to the first electrode post, and the second electrode tab is electrically connected to the second electrode post.
[0025] In some embodiments, a third direction is further provided, which intersects both the first direction and the second direction; at least two electrode assemblies are provided, and at least two electrode assemblies are stacked along the third direction;
[0026] The single cell further includes a first connecting piece, which connects the first tab and the first terminal; or / and the single cell further includes a second connecting piece, which connects the second tab and the second terminal.
[0027] This application also discloses a battery pack, including the single battery cells as described in the above embodiments.
[0028] Beneficial Effects: The single-cell battery of this application embodiment has intersecting first and second directions. The single-cell battery includes an electrode assembly; the electrode assembly includes a first electrode, a separator, and a second electrode, which are stacked and wound together. The electrode assembly has a flat region, a first corner region, and a second corner region, which are located on opposite sides of the flat region in the first direction. The electrode assembly also includes a first tab and a second tab. The first tab is disposed on the first electrode and located in the first corner region, and the second tab is disposed on the second electrode and located in the second corner region. The first tab and the second tab have opposite polarities and are located on the same side of the electrode assembly in the second direction. By disposing the first tab in the first corner region and the second tab in the second corner region, and extending the first tab and the second tab from the same side of the electrode assembly, compared to extending the tabs from the flat region of the electrode assembly, the space occupied in the middle of the battery is greatly reduced, and the energy density of the battery is improved.
[0029] The battery pack of this application embodiment includes the single battery cell as described in the above embodiments. Therefore, it can have all the technical features and effects of the single battery cell described above, which will not be repeated here. Attached Figure Description
[0030] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0031] Figure 1 This is a schematic diagram of the electrode assembly in a single battery cell according to an embodiment of this application, and the first tab and the second tab are not shown in the figure;
[0032] Figure 2 This is a schematic diagram of the electrode assembly in a single cell according to an embodiment of this application. The diagram shows the first tab and the second tab after being flattened.
[0033] Figure 3 This is a schematic diagram of the electrode assembly in a single cell according to an embodiment of this application, showing the positional relationship between the tabs and the electrode plates;
[0034] Figure 4 This is a schematic diagram of the first electrode and the first tab of the electrode assembly in the unfolded state of a single cell in an embodiment of this application;
[0035] Figure 5 This is a schematic diagram of the first electrode and the first tab of the electrode assembly in the unfolded state of a single cell in an embodiment of this application;
[0036] Figure 6 This is a schematic diagram of the internal structure of a single battery cell according to an embodiment of this application;
[0037] Figure 7 This is a schematic diagram of the internal structure of a single battery cell according to an embodiment of this application from another perspective.
[0038] Explanation of reference numerals in the attached drawings: 1. Electrode assembly; 11. First electrode; 12. Second electrode; 13. Diaphragm; 10. Straight region; 20. First corner region; 30. Second corner region; 14. First tab; 15. Second tab; 110. First corner segment; 120. Second corner segment; 141. First bend; 151. Second bend; 100. Slit; 111. First straight segment; 112. Third corner segment; 113. First tabless segment; 121. Second straight segment; 122. Fourth corner segment; 123. Second tabless segment; 142. First base; 152. Second base; 2. Housing; 200. Receiving cavity; 3. Top cover assembly; 31. Top cover plate; 32. First electrode post; 33. Second electrode post; 4. First connecting piece; 5. Second connecting piece;
[0039] X, first direction; Y, second direction; L, unfolding direction; Z, third direction. Detailed Implementation
[0040] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.
[0041] In the description of this application, it should be understood that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. In the description of this application, "multiple" means two or more, and "at least one" can refer to one, two, or more, unless otherwise explicitly specified. The terms "first," "second," and "third," etc., are only for the convenience of description and are used to name parts or embodiments by number, and do not imply any order of importance between the parts or embodiments.
[0042] It should also be noted that in the accompanying drawings of this application, arrows marked X indicate the first direction or its opposite, arrows marked Y indicate the second direction or its opposite, and arrows marked Z indicate the third direction or its opposite. The introduction of the first direction X, the second direction Y, and the third direction Z in the description of this application is to more clearly define the structure and relative positional relationships of the components in a single cell. In actual implementation, the second direction Y is generally a vertical direction or height direction, and the first direction X and the third direction Z are generally horizontal directions. The first direction X, the second direction Y, and the third direction Z intersect each other. Optionally, the first direction X, the second direction Y, and the third direction Z are perpendicular to each other to optimize the layout of the single cell. In the description of this application, "perpendicular" means completely perpendicular to 90° or almost completely perpendicular; for example, an angle between 80° and 100° is considered perpendicular. Similarly, "parallel" means completely parallel or almost completely parallel; for example, a completely parallel angle within 10° is considered parallel.
[0043] As a preamble to the embodiments of this application, lithium-ion power batteries have advantages such as small size, large capacity, high energy density, high charge / discharge rate, excellent low-temperature performance, long service life, and high safety. However, in conventional square aluminum-cased power batteries, when the electrode sheets are wound and assembled into the casing, the lead-out position of the electrode tabs is located on the straight edge of the core body, or the electrode tabs are led out from both sides, occupying the vertical space inside the battery. At the same time, in the process of connecting the electrode tabs and the terminals, the end faces of the electrode tabs need to be gathered and welded together first, then the welded electrode tabs are welded to the adapter piece, and then the adapter piece is connected to the cover plate terminal piece by laser welding. The above welding method is cumbersome. The electrode tabs have a first bend at the gathering position, and the bend direction is different. The electrode tabs have a second bend at the welding position with the adapter piece. The two bends result in the electrode tabs being too long, the foil utilization rate being low, and the height of the electrode tabs after welding with the adapter piece being too high, occupying a lot of space in the middle part of the battery. The addition of other components in the middle area seriously affects the energy density of the battery.
[0044] In view of this, embodiments of this application provide a single-cell battery, which aims to solve at least one of the above-mentioned technical problems.
[0045] The single-cell battery disclosed in this application has intersecting first direction X and second direction Y. The single-cell battery includes an electrode assembly 1. The electrode assembly 1 includes a first electrode 11, a separator 13 and a second electrode 12. The first electrode 11, the separator 13 and the second electrode 12 are stacked and wound together. The electrode assembly 1 has a straight region 10, a first corner region 20 and a second corner region 30. The first corner region 20 and the second corner region 30 are respectively located on opposite sides of the straight region 10 in the first direction X. The electrode assembly 1 also includes a first tab 14 and a second tab 15. The first tab 14 is connected to the first electrode 11 and is located in the first corner region 20. The second tab 15 is connected to the second electrode 12 and is located in the second corner region 30. The first tab 14 and the second tab 15 have opposite polarities and are located on the same side of the electrode assembly 1 in the second direction Y.
[0046] The first tab 14 is connected to the first electrode 11 and corresponds to the positive electrode region of the battery. The second tab 15 is connected to the second electrode 12 and corresponds to the negative electrode region of the battery. By placing the first tab 14 and the second tab 15 on the same side of the electrode assembly 1, the space occupied inside the battery in the second direction Y is reduced, and the current path is shortened. Compared with the traditional structure where the tabs are placed in the straight area 10, placing the tabs in the corner area also greatly reduces the space occupied in the middle of the battery, reserving space for other components and reducing the overall height occupied in the second direction Y. Combining the placement of the tabs in the corner area of the electrode assembly 1 reduces the overlap of the projection of the tabs and electrodes in the second direction Y, reducing the occupation of the effective space inside the battery and improving the energy density of the battery.
[0047] In some embodiments, the first electrode 11 includes a first corner segment 110, which has multiple segments stacked in a first corner region 20; the multiple first corner segments 110 are provided with first tabs 14. The second electrode 12 includes a second corner segment 120, which has multiple segments stacked in a second corner region 30; the multiple second corner segments 120 are provided with second tabs 15.
[0048] First tabs 14 are provided on multiple first corner segments 110 of the first electrode 11 (stacked in the first corner region 20), and second tabs 15 are provided on multiple second corner segments 120 of the second electrode 12 (stacked in the second corner region 30). This stacked structure with tabs in the corner regions results in a compact layout, high reliability, and high structural strength. Furthermore, the independent tabs on the corner segments of the multi-layered electrodes, especially the tabs on the corner segments of each layer, significantly shorten the current transmission path and reduce internal resistance. The first tabs 14 and second tabs 15 are distributed on both sides of the first direction X, resulting in uniform stress distribution and high stability.
[0049] In some embodiments, such as Figure 4As shown, both the first electrode 11 and the second electrode 12 have an unfolding direction L; the first electrode tab 14 includes a plurality of first bends 141, which are connected to the same first corner segment 110. The plurality of first bends 141 located on the same first corner segment 110 are arranged along the unfolding direction L of the first electrode 11; when the electrode assembly 1 is in a wound state, that is, after the first electrode 11 is wound, at least two first bends 141 are bent and stacked in the second direction Y and electrically connected; as Figure 5 As shown, the second electrode tab 15 includes a plurality of second bends 151, which are connected to the same second corner segment 120. The plurality of second bends 151 located on the same second corner segment 120 are arranged along the unfolding direction L of the second electrode 12. When the electrode assembly 1 is in a wound state, that is, after the second electrode 12 is wound, at least two second bends 151 are bent and stacked in the second direction Y and electrically connected.
[0050] The first tab 14 and the second tab 15 adopt a structure with multiple bends. After the electrode assembly 1 is wound, the tabs are flattened. The number of bends can be arranged based on the size of the corner segments of the electrode sheet, so that the current carrying capacity of different layers of electrode sheets is balanced. The number of corner segments on the inner layer of electrode sheet is less than the number of corner segments on the outer layer of electrode sheet. The length of the tab can be positively correlated with the winding size of the corresponding winding layer of electrode sheet, so that the tabs of each layer can meet the maximum current carrying capacity, the current density distribution is more uniform, and the safety and electrochemical performance of the battery are improved.
[0051] In addition, by stacking the electrodes in the second direction Y after bending at least two bends, on the one hand, current conduction between the inner and outer layers of the same polarity electrodes after winding is achieved, further reducing the internal resistance of the battery; on the other hand, stress transmission is generated between the bends, resulting in a more uniform stress distribution, higher structural strength, better resistance to compression, and improved stability of the tabs. Compared to leading out the tabs in the straight area 10 of the electrode assembly 1, by setting multiple bends to overlap and connect and lead out in the corner area to form tabs, and interlocking between adjacent bends, the problem of stress concentration at the connection between the tab and the connecting piece after the tab is bent is solved, reducing the risk of unstable current transmission.
[0052] In some embodiments, such as Figure 4 and Figure 5 As shown, both the first electrode tab 14 and the second electrode tab 15 are provided with multiple slits 100. Among them:
[0053] Multiple slits 100 on the first electrode tab 14 are spaced apart along the unfolding direction L of the first electrode plate 11, and a slit 100 is provided between two adjacent first bending portions 141.
[0054] The slit 100 can have a size of almost 0 or very small in the unfolding direction L, that is, the slit 100 is a tangent. After cutting, the cut surfaces of two adjacent first bends 141 are roughly in contact in the unfolding direction L, thereby forming multiple independent first bends 141.
[0055] The slit 100 can also be larger in the unfolding direction L and form a gap so that two adjacent first bends 141 are spaced apart.
[0056] Multiple slits 100 on the second electrode tab 15 are spaced apart along the unfolding direction L of the second electrode plate 12, and a slit 100 is provided between two adjacent second bending portions 151.
[0057] Similar to the slit arrangement on the first electrode tab 14, the size of the slit 100 on the second electrode tab 15 in the unfolding direction L can be almost 0 or very small, or it can be large, forming a gap, which will not be elaborated further.
[0058] The corner area is where the winding deformation is greatest. The slit 100 divides the continuous electrode material into independent bending units, avoiding stress concentration during bending that could lead to breakage or random wrinkling that could result in uncontrollable thickness. By setting multiple slits 100 on the tabs, the difficulty of flattening the tabs is reduced, as is the redundancy that occurs after flattening. Simultaneously, the slits 100 allow the bent portions to be staggered and nested during stacking, reducing abrupt thickness changes in localized areas of the tabs and improving the compactness of the electrode assembly 1.
[0059] In other embodiments, by arranging multiple bent portions at intervals along the unfolding direction L on the electrode sheet, a blank area is formed between adjacent bent portions. On the one hand, this reduces material stacking, improves the problem of large-area protrusions after the bent portions overlap, and improves compactness; on the other hand, it improves the flexibility of the bent portions, reduces bending deformation, improves the uniformity of the current path, and reduces internal resistance.
[0060] In some embodiments, each first corner segment 110 of a layer is provided with a first electrode 14, and two adjacent first bends 141 on the first corner segment 110 of the same layer are stacked in the second direction Y; each second corner segment 120 of a layer is provided with a second electrode 15, and two adjacent second bends 151 on the second corner segment 120 of the same layer are stacked in the second direction Y.
[0061] By overlapping and connecting adjacent bends on the same layer, a stable connection is formed between adjacent bends, which improves the overall structural stability of the tabs and reduces the risk of tearing under stress. At the same time, it improves the uniformity of current transmission density of the tabs and increases heat dissipation capacity.
[0062] In some embodiments, each first corner segment 110 is provided with a first electrode 14, and the first bending portions 141 on two adjacent first corner segments 110 are stacked in the second direction Y; each second corner segment 120 is provided with a second electrode 15, and the second bending portions 151 on two adjacent second corner segments 120 are stacked in the second direction Y.
[0063] By stacking and connecting two adjacent bent sections in the second direction Y, current conduction between the inner and outer layers after the electrode is wound is achieved, further reducing the internal resistance of the battery; on the other hand, stress transmission between the bent sections is made more uniform, and the stability of the electrode tab is improved.
[0064] In some embodiments, two adjacent bends on the corner segment of the same layer are stacked in the second direction Y; simultaneously, the bends on the corner segments of two adjacent layers are stacked in the second direction Y. It should be understood that by stacking and connecting adjacent bends on the same layer, and stacking and connecting bends on the second direction Y of adjacent layers, the tab as a whole has a three-dimensional structure, which further increases the structural stability of the tab; at the same time, it reduces the internal resistance of the battery and improves the overcurrent capacity of the battery.
[0065] In some embodiments, such as Figure 1 As shown, the first electrode 11 further includes a first straight section 111, a third corner section 112, and a first tab section 113. The first straight section 111 has multiple sections and is stacked in the straight region 10. The third corner section 112 has multiple sections and is stacked in the second corner region 30. Along the unfolding direction L of the first electrode 11, the first straight section 111 is connected between the first corner section 110 and the third corner section 112. The second electrode 12 further includes a second straight section 121, a fourth corner section 122, and a second tab section 123. The second straight section 121 has multiple sections and is stacked in the straight region 10. The fourth corner section 122 has multiple sections and is stacked in the first corner region 20. Along the unfolding direction L of the second electrode 12, the second straight section 121 is connected between the second corner section 120 and the fourth corner section 122.
[0066] Each electrode adopts a layout with two corner sections and a straight section, which ensures a stable center of gravity and high structural stability, and can balance the winding stress. At the same time, the first corner section 110 and the second corner section 120 realize bidirectional current collection, shortening the electron transport path, while the straight section serves as an intermediate transport region, reducing the internal resistance of the battery.
[0067] It is understandable that the first corner segment 110 and the fourth corner segment 122 overlap to form the main part of the first corner area 20, while the second corner segment 120 and the third corner segment 112 overlap to form the main part of the second corner area 30.
[0068] The first stepless lug segment 113 is located at the starting end of the winding of the first electrode 11. The first stepless lug segment 113 is connected to the first corner segment 110, the first straight segment 111, or the third corner segment 112, and the first stepless lug segment 113 is wound at least two turns. The second stepless lug segment 123 is located at the starting end of the winding of the second electrode 12. The second stepless lug segment 123 is connected to the second corner segment 120, the second straight segment 121, or the fourth corner segment 122, and the second stepless lug segment 123 is wound at least two turns.
[0069] By setting up tabless sections, the space required for the inner ring tabs to be flattened is reserved to ensure that there are no abnormal overlaps or damages to the inner ring tabs after the flattening process, thus improving the safety of individual cells.
[0070] It should be noted that:
[0071] The winding start end of the first electrode tab 14 refers to the fact that the first electrode tab 14 has a first end and a second end in the winding direction. During winding, the first end is the starting end, and the second end is the tail end after winding is completed. The first end is the winding start end of the first electrode tab 14. The winding start end of the second electrode tab 15 is explained in the same way as the winding start end of the first electrode tab, and will not be repeated.
[0072] In some embodiments, such as Figure 4 As shown, the first electrode tab 14 also includes a first base 142, which connects the first corner segment 110 and the first bend 141, and the lengths of the first base 142 and the corresponding first corner segment 110 in the unfolding direction L of the first electrode 11 are equal; Figure 5 As shown, the second tab 15 also includes a second base 152, which connects the second corner segment 120 and the second bent portion 151. The second base 152 and the corresponding second corner segment 120 have equal lengths in the unfolding direction L of the second electrode 12. It should be understood that the base enables a transition connection between the corner segment and the bent portion. Simultaneously, the base supports the bending action of the bent portion, preventing the flattened bent portion from connecting with the corner segment, reducing the risk of hard contact damage between the electrode and the tab, and improving the safety of the single-cell battery. The equal length of the base and the corner segment enhances the support for the bent portion, allowing for a more uniform distribution of stress generated during bending. Furthermore, the connection between the base and the electrode enables current transfer between the tab and the electrode, further improving the overcurrent capacity of the single-cell battery and resulting in a more uniform current density distribution.
[0073] In some embodiments, such as Figure 2 and Figure 3As shown, at least two first bends 141 are stacked and welded; at least two second bends 151 are stacked and welded. It should be understood that by interlocking the welding between the multiple layers of bends to form an integral structure, the conductive paths are richer, internal resistance is reduced, and the interlayer connections are tighter, improving the reliability of current transmission. Furthermore, three or more consecutive bends can be welded together, reducing the number of welding operations, simplifying the welding process, and improving sample preparation efficiency.
[0074] In some embodiments, such as Figure 6 and Figure 7 As shown, the single battery also includes: a housing 2 and a top cover assembly 3; the housing 2 has a receiving cavity 200; the top cover assembly 3 includes a top cover plate 31, a first electrode post 32 and a second electrode post 33, the top cover plate 31 is connected to the housing 2 and covers the receiving cavity 200, the first electrode post 32 and the second electrode post 33 are disposed on the top cover plate 31, and at least one of the first electrode post 32 and the second electrode post 33 is insulated from the top cover plate 31; the electrode assembly 1 is disposed in the receiving cavity 200, and the first electrode tab 14 is electrically connected to the first electrode post 32, and the second electrode tab 15 is electrically connected to the second electrode post 33.
[0075] By setting the tabs in the corner area, the tabs are bent and connected to the terminal post. Each layer of tabs only needs to be bent once, which reduces the height requirement of the tabs and improves the utilization rate of foil materials. At the same time, it reduces the height dimension of multiple layers of tabs after bending, saves internal battery space, and improves battery energy density.
[0076] It is understandable that: Figure 7 The distribution of the first electrode post 32 and the second electrode post 33 in the second direction Y is given only. In actual arrangement, the size of the electrode assembly 1 in the first direction X is larger than the size in the third direction Z. That is, the length direction of the electrode assembly 1 is the first direction X, and the width direction is the third direction Z.
[0077] In some embodiments, a third direction Z is also provided, which intersects both the first direction X and the second direction Y; at least two electrode assemblies 1 are provided, and at least two electrode assemblies 1 are stacked along the third direction Z; the single cell also includes a first connecting piece 4, which connects all the first tabs 14 and the first terminal posts 32; or / and, the single cell also includes a second connecting piece 5, which connects all the second tabs 15 and the second terminal posts 33.
[0078] At least two electrode assemblies 1 are stacked along the third direction Z to increase the total amount of active material, improve the volumetric energy density of the battery, and increase the battery's capacity. The first connecting piece 4 connects all the first tabs 14 to the first terminal 32 in parallel, and the second connecting piece 5 connects all the second tabs 15 to the second terminal 33 in parallel, forming a low internal resistance conductive network to improve high-rate discharge performance.
[0079] This application also discloses a battery pack, including the single battery cells as described in the above embodiments. Therefore, it can possess all the technical features and effects of the aforementioned single battery cells, which will not be repeated here.
[0080] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.
[0081] The single-cell battery and battery pack provided in the embodiments of this application have been described in detail above, and specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A unit cell having a first direction (X) and a second direction (Y) intersecting, characterized in that, The electrode assembly (1) comprises a first electrode tab (11), a separator (13) and a second electrode tab (12), which are stacked and wound, and has a flat area (10), a first corner area (20) and a second corner area (30), wherein the first corner area (20) and the second corner area (30) are respectively connected to opposite sides of the flat area (10) in the first direction (X). The electrode assembly (1) further comprises a first tab (14) and a second tab (15), wherein the first tab (14) is connected to the first electrode tab (11) and located in the first corner area (20), the second tab (15) is connected to the second electrode tab (12) and located in the second corner area (30), and the polarities of the first tab (14) and the second tab (15) are opposite and located on the same side of the electrode assembly (1) in the second direction (Y). The first electrode tab (11) comprises a first corner section (110), and a plurality of first corner sections (110) are stacked in the first corner area (20); the first corner sections (110) are provided with the first tab (14).
2. The cell according to claim 1, wherein The second electrode tab (12) comprises a second corner section (120), and a plurality of second corner sections (120) are stacked in the second corner area (30); the second corner sections (120) are provided with the second tab (15). The first electrode tab (11) and the second electrode tab (12) each have an unfolding direction (L).
3. The cell according to claim 2, wherein The first tab (14) comprises a plurality of first bending portions (141), a plurality of first bending portions (141) are connected to the same first corner section (110), and a plurality of first bending portions (141) are arranged along the unfolding direction (L) of the first electrode tab (11); when the electrode assembly (1) is in a wound state, at least two first bending portions (141) are stacked and electrically connected in the second direction (Y) after being bent. The second tab (15) comprises a plurality of second bending portions (151), a plurality of second bending portions (151) are connected to the same second corner section (120), and a plurality of second bending portions (151) are arranged along the unfolding direction (L) of the second electrode tab (12); when the electrode assembly (1) is in a wound state, at least two second bending portions (151) are stacked and electrically connected in the second direction (Y) after being bent. The first tab (14) and the second tab (15) are each provided with a plurality of slits (100), the plurality of slits (100) on the first tab (14) are arranged at intervals along the unfolding direction (L) of the first electrode tab (11), and one slit (100) is arranged between adjacent two first bending portions (141).
4. The cell according to claim 3, wherein The plurality of slits (100) on the second lug (15) are arranged at intervals along the development direction (L) of the second tab (12), and one slit (100) is arranged between two adjacent second bending portions (151).
5. The cell according to claim 3, wherein Each layer of the first corner section (110) is provided with the first lug (14), and two adjacent first bending portions (141) on the same layer of the first corner section (110) are arranged in a stacked manner in the second direction (Y); or / and, the first bending portions (141) on two adjacent layers of the first corner section (110) are arranged in a stacked manner in the second direction (Y). Each layer of the second corner section (120) is provided with the second lug (15), and two adjacent second bending portions (151) on the same layer of the second corner section (120) are arranged in a stacked manner in the second direction (Y); or / and, the second bending portions (151) on two adjacent layers of the second corner section (120) are arranged in a stacked manner in the second direction (Y).
6. The cell according to claim 5, wherein The first tab (11) further comprises a first flat section (111), a third corner section (112) and a first lug-free section (113), the first flat section (111) is provided with a plurality of layers in the flat area (10), the third corner section (112) is provided with a plurality of layers in the second corner area (30), and the first flat section (111) is connected between the first corner section (110) and the third corner section (112) along the development direction (L) of the first tab (11); the first lug-free section (113) is located at the winding starting end of the first tab (11), the first lug-free section (113) is connected with the first corner section (110) or the first flat section (111) or the third corner section (112), and the first lug-free section (113) is wound at least two turns; The second tab (12) further comprises a second flat section (121), a fourth corner section (122) and a second lug-free section (123), the second flat section (121) is provided with a plurality of layers in the flat area (10), the fourth corner section (122) is provided with a plurality of layers in the first corner area (20), and the second flat section (121) is connected between the second corner section (120) and the fourth corner section (122) along the development direction (L) of the second tab (12); the second lug-free section (123) is located at the winding starting end of the second tab (12), the second lug-free section (123) is connected with the second corner section (120) or the second flat section (121) or the fourth corner section (122), and the second lug-free section (123) is wound at least two turns.
7. The cell according to claim 3, wherein The first lug (14) further comprises a first base (142) connected between the first corner section (110) and the first bent part (141), and the length of the first base (142) in the development direction (L) of the first tab (11) is equal to that of the corresponding first corner section (110); or / and, at least two first bent parts (141) are stacked and welded; The second lug (15) further comprises a second base (152) connected between the second corner section (120) and the second bent part (151), and the length of the second base (152) in the development direction (L) of the second tab (12) is equal to that of the corresponding second corner section (120); or / and, at least two second bent parts (151) are stacked and welded.
8. The monobloc cell according to any one of claims 1 to 7, characterized in that, The single battery further comprises: a housing (2) having an accommodating cavity (200); a top cover assembly (3) comprising a top cover sheet (31), a first pole post (32) and a second pole post (33), the top cover sheet (31) being connected with the housing (2) and sealing the accommodating cavity (200), the first pole post (32) and the second pole post (33) being arranged on the top cover sheet (31), and at least one of the first pole post (32) and the second pole post (33) being insulated from the top cover sheet (31); The electrode assembly (1) is arranged in the accommodating cavity (200), and the first lug (14) is electrically connected with the first pole post (32), and the second lug (15) is electrically connected with the second pole post (33).
9. The cell according to claim 8, wherein There is further a third direction (Z) intersecting both the first direction (X) and the second direction (Y); the electrode assembly (1) is provided in at least two, and the at least two electrode assemblies (1) are stacked along the third direction (Z); The single battery further comprises a first connecting sheet (4) connecting the first lug (14) and the first pole post (32); or / and, the single battery further comprises a second connecting sheet (5) connecting the second lug (15) and the second pole post (33).
10. A battery pack, characterized by, The single battery comprises the single battery as claimed in any one of claims 1 to 9. The single battery comprises the single battery as claimed in any one of claims 1 to 9.