Cover plate assembly, battery cell, and battery

Abstract

The present application provides a cover plate assembly, a battery cell, and a battery. The cover plate assembly comprises a cover plate and poles. The cover plate is provided with mounting holes, and the cover plate has a width dimension W and a length dimension L. Each pole comprises a main body; one end of the main body is provided with a tab connection slot; the main body passes through the corresponding mounting hole; in the direction of the width dimension W, the main body has a width dimension b'; and in the direction of the length dimension L, the main body has a length dimension a', wherein W-6 mm ≤ b' ≤ W-8 mm, and 0.4 ≤ b' / a' ≤ 0.9.

Description

Cover assembly, cells and batteries

[0001] This application claims priority to Chinese patent applications Nos. 202422764050.9 and 202422764097.5, filed on November 12, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, specifically to a cover plate assembly, a battery cell, and a battery. Background Technology

[0003] A single battery cell includes a casing, a cover assembly that fits over the casing, and an electrode assembly disposed within the casing. The cover assembly includes a cover plate, terminals disposed on the cover plate, an upper plastic component that insulates the upper end of the terminals from the top of the cover plate, and a lower plastic component that insulates the cover plate from the electrode assembly and the lower end of the terminals. The electrode assembly is connected to the lower end of the terminals via tabs. The upper end of the terminals is connected to a connector bar, allowing multiple single batteries to be connected in series or parallel via the connector bar.

[0004] In related technologies, in order to ensure the overcurrent capacity of a single cell and improve the ease of welding between the terminal and the corresponding component, the size of the terminal is set to be relatively large. Invention Overview

[0005] However, in square single-cell batteries, the cover plate is rectangular, which has a limited width, thus restricting the width of the terminals. This results in poor current carrying capacity of the terminals.

[0006] In a first aspect, this application provides a cover plate assembly, which includes a cover plate and an electrode post; the cover plate is provided with a mounting hole and has a width dimension W and a length dimension L; the electrode post includes a body, one end of which is provided with an electrode lug connecting groove, the body is inserted into the mounting hole, the body has a width dimension b' along the direction of the width dimension W, and has a length dimension a' along the direction of the length dimension L; wherein, W-6mm≤b'≤W-8mm, and 0.4≤b' / a'≤0.9.

[0007] Secondly, this application provides a battery cell, which includes a housing, an electrode assembly, a tab assembly, and the aforementioned cover assembly; the housing has a receiving cavity; the electrode assembly is disposed in the receiving cavity; the cover assembly is closed with the housing; one end of the tab assembly is connected to the electrode assembly, and the other end is located in the tab connection groove and connected to the inner wall of the tab connection groove.

[0008] Thirdly, this application provides a battery, which includes a housing assembly and the aforementioned battery cells; the housing assembly has a mounting cavity; there are multiple battery cells, which are disposed in the mounting cavity, and the multiple battery cells are connected in series and / or in parallel. Beneficial effects

[0009] This application, by limiting the width dimension b' of the main body relative to the width dimension W of the cover plate, can both enable the main body to have a larger width dimension and ensure the strength of the cover plate in the width direction; at the same time, by limiting the length dimension a' of the main body relative to the width dimension b' of the main body, it can avoid the length dimension a' of the main body being too small, thereby enabling the electrode post to have a larger length dimension, which in turn can improve the current carrying capacity of the electrode post. Attached Figure Description

[0010] Figure 1 is a schematic diagram of the structure of the cover plate assembly provided in an embodiment of this application;

[0011] Figure 2 is a structural schematic diagram of the cover plate assembly provided in an embodiment of this application from another perspective;

[0012] Figure 3 is a partial top view of a cover plate assembly provided in an embodiment of this application;

[0013] Figure 4 is a partial bottom view of the cover plate assembly provided in an embodiment of this application;

[0014] Figure 5 is a cross-sectional view of AA in Figure 3;

[0015] Figure 6 is a schematic diagram showing the positions of the tab assembly and the support structure provided in the implementation of this application;

[0016] Figure 7 is a partial structural schematic diagram of the cover plate assembly provided in an embodiment of this application;

[0017] Figure 8 is an enlarged view of point B in Figure 7;

[0018] Figure 9 is a cross-sectional view of the support structure provided in an embodiment of this application;

[0019] Figure 10 is a partial structural schematic diagram of the lower plastic part provided in an embodiment of this application;

[0020] Figure 11 is a schematic diagram of the battery cell structure provided in an embodiment of this application;

[0021] Figure 12 is a schematic diagram showing the overall structure of the battery cell involved in this application.

[0022] Figure 13 is a schematic diagram showing the overall structure of the battery cell involved in this application.

[0023] Figure 14 is a schematic diagram showing the overall structure of the battery cell involved in this application.

[0024] Figure 15 is a graph showing the relationship between the cell volume and the area of ​​the positive electrode solder pad area involved in this application.

[0025] Figure 16 is a graph showing the relationship between the cell capacity and the area of ​​the positive electrode solder pad area involved in this application.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1-Lower plastic part;

[0028] 11-Body; 111-First long side; 12-First surface; 13-First through hole; 14-Support structure; 141-Support part; 143-Connecting part; 15-Connecting structure; 16-Second surface; 17-Reinforcing platform; 18-Groove; 181-Drainage through hole; 19-Reinforcing rib;

[0029] 2-Cover plate assembly; 21-Cover plate; 22-Pole post; 221-Pole lug connecting groove; 222-Main body; 223-Flanged edge; 224-First end; 23-Pressure block; 24-Upper plastic part; 25-Sealing ring;

[0030] 3-Battery cell; 31-Housing; 32-Electrode assembly; 33-Taper assembly;

[0031] 1a - Positive electrode tab; 11a - Positive electrode solder area; 2a - Negative electrode tab; 21a - Negative electrode solder area. Embodiments of the present invention

[0032] Please refer to Figures 1 to 3. Figure 1 is a structural schematic diagram of the cover plate assembly 2 provided in an embodiment of this application. Figure 2 is a structural schematic diagram of the cover plate assembly 2 provided in an embodiment of this application from another perspective. Figure 3 is a partial top view provided in an embodiment of this application. An embodiment of this application provides a cover plate assembly 2. The cover plate assembly 2 includes a cover plate 21 and a pole post 22. The cover plate 21 is provided with a mounting hole. The cover plate 21 has a width dimension W and a length dimension L. The pole post 22 includes a body 222. One end of the body 222 is provided with a tab connecting groove 221. The body 222 passes through the mounting hole. Along the direction of the width dimension W, the body 222 has a width dimension b'. Along the direction of the length dimension L, the body 222 has a length dimension a'. W-6mm≤b'≤W-8mm, and 0.4≤b' / a'≤0.9.

[0033] The ratio between the width dimension b' and the length dimension a' includes, but is not limited to, 0.4, 0.44, 0.48, 0.5, 0.52, 0.55, 0.58, 0.6, 0.63, 0.65, 0.68, 0.7, 0.74, 0.76, 0.78, 0.8, 0.82, 0.85, 0.88, and 0.9.

[0034] In addition, the width dimension b' of the main body 222 includes, but is not limited to, W-6mm, W-6.2mm, W-6.4mm, W-6.5mm, W-6.6mm, W-6.7mm, W-6.38mm, W-7mm, W-7.2mm, W-7.5mm, W-7.6mm, W-7.7mm, W-7.8mm, and W-8mm.

[0035] It is understandable that the cover plate 21 is a rectangular plate structure, which is used in square battery cells.

[0036] It is understandable that the selection of the length dimension a' of the pole post 22 is based on the fundamental requirement that the installation of the pole post 22 does not interfere with or affect the assembly of other components. For example, when one pole post 22 is provided on the cover plate 21, the length dimension L of the cover plate 21 can be larger, or the length dimension a' of the pole post 22 can be larger; when two pole posts 22 are provided on the cover plate 21, the length dimension L of the cover plate 21 can be larger, or the length dimension a' of the pole post 22 can be smaller. In addition, when an injection hole or an explosion-proof valve mounting hole is also provided on the cover plate 21, the length dimension L of the cover plate 21 or the length dimension a' of the pole post 22 should be adjusted accordingly.

[0037] It is understood that the cover assembly 2 may also include a sealing ring 25 and an upper plastic part 24. Therefore, the difference between the width dimension W of the cover 21 and the width dimension b' of the main body can, on the one hand, ensure the strength of the cover 21 after the mounting holes are provided, so as to avoid the deformation of the cover 21 during assembly or use; on the other hand, it can reserve installation space for the upper plastic part 24 and the sealing ring 25.

[0038] It is understandable that the pole post 22 is a square pole post 22 with chamfered corners, the chamfer radius being 0.1~2mm.

[0039] In this embodiment, by limiting the width dimension b' of the main body 222 relative to the width dimension W of the cover plate 21, the main body 222 can have a larger width dimension while ensuring the strength of the cover plate 21 in the width direction. At the same time, by limiting the length dimension a' of the main body 222 relative to the width dimension b' of the main body 222, on the one hand, the length dimension a' of the main body 222 can be avoided from being too small, thereby allowing the pole post 22 to have a larger length dimension, which can improve the current carrying capacity of the pole post 22. On the other hand, it not only avoids the length dimension a' of the main body 222 from being too large and affecting the arrangement of other components on the cover plate 21, but also ensures the strength of the cover plate 21 in the length direction.

[0040] Furthermore, by limiting the length dimension a' of the main body 222 relative to its width dimension b', the terminal post 22 has a suitable length dimension, thereby allowing for a larger width dimension of the tab connected to it. This not only improves the current collection capacity of the battery cell but also enhances the ease of welding the tab to the terminal post 22.

[0041] Please refer to Figure 4, which is a partial bottom view of the cover plate assembly 2 provided in an embodiment of this application. In one embodiment, the tab connecting groove 221 has a width dimension d along the direction of the width dimension W and a length dimension c along the direction of the length dimension L, satisfying: 0.4 ≤ d / c ≤ 0.9. This gives the tab connecting groove 221 a suitable width-to-length ratio, improving the stability of the fit between the tab connecting groove 221 and the tab, and facilitating welding between the tab and the tab connecting groove 221.

[0042] It can be understood that the direction of the length dimension c is parallel to the direction of the width dimension of the tab; while the direction of the width dimension d is consistent with the direction of the height dimension of the part of the tab located in the tab connecting groove 221.

[0043] The ratio of the width dimension d to the length dimension c includes, but is not limited to, 0.4, 0.44, 0.48, 0.5, 0.52, 0.55, 0.58, 0.6, 0.63, 0.65, 0.68, 0.7, 0.74, 0.76, 0.78, 0.8, 0.82, 0.85, 0.88, and 0.9.

[0044] In one embodiment, d / c = b' / a', which can improve the uniformity of the pole post 22 structure and improve the stress state of the pole post 22.

[0045] Please refer to Figure 5, which is a cross-sectional view of AA in Figure 3. In one embodiment, the thickness of the groove wall of the tab connection groove 221 is D, which satisfies: 0.8mm≤D≤1.5mm.

[0046] The thickness D of the groove wall of the tab connection groove 221 includes, but is not limited to, 0.8mm, 0.85mm, 0.8mm, 0.92mm, 0.86mm, 1mm, 1.1mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.46mm, and 1.5mm.

[0047] In this embodiment, by limiting the thickness D of the groove wall of the tab connecting groove 221, on the one hand, the strength of the groove wall of the tab connecting groove 221 can be guaranteed, and the pole post 22 can be prevented from deforming; on the other hand, the tab connecting groove 221 can have a larger size, which can not only increase the size of the tab that it is matched with, but also improve the ease of operation of welding the tab to it.

[0048] Referring to Figure 5, in one embodiment, the electrode post 22 further includes a flange 223. The electrode post 22 has a first end 224 configured to face the electrode assembly of the battery cell. The flange 223 is disposed on the outer peripheral surface of the body 222 and adjacent to the first end 224. The flange 223 engages with the cover plate 21. Thus, when the internal pressure of the battery cell is high, the engagement of the flange 223 with the cover plate 21 effectively prevents the electrode post 22 from detaching from the cover plate 21.

[0049] In addition, when the cover plate assembly 2 also includes a lower plastic part 1, the flange 223 overlaps with the lower plastic part 1, and the portion of the lower plastic part 1 near the pole post 22 is located between the flange 223 and the cover plate 21. In this way, the lower plastic part 1 can be fixed by the flange 223, thereby improving the reliability of the lower plastic part 1's fixation.

[0050] Referring to Figure 2 or Figure 4, in one embodiment, the flange 223 extends in a ring shape along the circumference of the pole post 22. This not only improves the uniformity of the pole post 22 structure, thus improving the stress state of the pole post 22, but also improves the uniformity of the stress at the stop-fitting part between the pole post 22 and the cover plate 21, thereby improving the stress state of the cover plate assembly 2.

[0051] Referring to Figure 4, in one embodiment, the outer edge of the flange 223 has a width dimension b along the direction of the width dimension W, and a length dimension a along the direction of the length dimension L, satisfying: 0.4 ≤ a / b ≤ 0.9. This gives the flange 223 a suitable width-to-length ratio, improving the stability of the stop fit between the flange 223 and the cover plate 21, and allowing control over the amount of material used in the flange 223.

[0052] The ratio of the width dimension b to the length dimension a includes, but is not limited to, 0.4, 0.44, 0.48, 0.5, 0.52, 0.55, 0.58, 0.6, 0.63, 0.65, 0.68, 0.7, 0.74, 0.76, 0.78, 0.8, 0.82, 0.85, 0.88, and 0.9.

[0053] In one embodiment, a / b = b' / a', which can improve the uniformity of the structure of the pole post 22 and thus improve the stress state of the pole post 22.

[0054] Please refer to Figure 3 or Figure 5. In one embodiment, the flange 223 has a width dimension e along the radial direction of the mounting hole, satisfying 1.5mm≤e≤2mm.

[0055] The flange 223 has a width dimension e including but not limited to 1.5mm, 1.6mm, 1.65mm, 1.7mm, 1.76mm, 1.8mm, 1.83mm, 1.9mm, 1.95mm, 1.98mm, and 2mm.

[0056] In this embodiment, by limiting the width dimension e of the 1.5mm flange 223, on the one hand, the size of the flange 223 is too large and interferes with the shell or the insulation gap is insufficient; on the other hand, the flange 223 has a sufficient width dimension, thereby improving the reliability of the stop fit between the flange 223 and the cover plate 21.

[0057] Referring to Figure 2, in one embodiment, the cover plate assembly 2 further includes a lower plastic component 1. The lower plastic component 1 includes a body 11. One side of the body 11 is connected to one side of the cover plate 21. The body 11 is provided with a first through hole 13. The main body 222 also passes through the first through hole 13.

[0058] It is understandable that the flange 223 overlaps with the side of the lower plastic part 1 that is away from the cover plate 21.

[0059] In this embodiment, by providing the lower plastic part 1, the insulation between the cover plate 21 and the electrode assembly of the battery cell can be improved, thereby improving the reliability of the battery cell.

[0060] Referring to Figure 2, in one embodiment, the body 11 has a first surface 12 facing away from the cover plate 21, and a support structure 14 is provided protruding outward from the first surface 12. The support structure 14 is disposed adjacent to the pole post 22, and the support structure 14 is configured to abut against the tab of the battery cell along the axis of the mounting hole.

[0061] It is understood that, in order to facilitate the insertion of the end of the electrode assembly into the electrode connecting groove 221, the electrode is trapezoidal, and its width gradually increases as it approaches the electrode plate. Therefore, during welding, the end of the electrode assembly furthest from the electrode plate is smaller in size and is located within the electrode connecting groove 221, as shown in Figure 6. Figure 6 is a schematic diagram of the position of the electrode assembly and the support structure 14 provided in the embodiment of this application. Correspondingly, the portion of the electrode assembly located outside the first through hole 13 is supported by the support structure 14.

[0062] In this embodiment, by providing a support structure 14, the tab assembly can be supported when welding the tab assembly to the pole post 22, thereby reducing the deformation of the tab assembly and improving the flatness of the contact area between the tab and the pole post 22, ultimately improving the welding reliability between the tab assembly and the pole post 22.

[0063] Please refer to Figure 7, which is a partial structural schematic diagram of the cover plate assembly 2 provided in an embodiment of this application. In one embodiment, the body 11 has two first long sides 111 parallel to the direction of the length dimension L, and a support structure 14 is provided on the body 11 at least near one of the first long sides 111; the support structure 14 includes two support parts 141, which are symmetrically distributed along the axis of the first through hole 13.

[0064] It is understood that the tabs of some square cells are bent in the same direction, that is, the tabs are located on one side of the width direction of the lower plastic part 1; correspondingly, a support structure 14 is provided on the body 11 near one of the first long sides 111.

[0065] It is understood that some square battery cells have two tab groups, which are bent relative to each other; correspondingly, support structures 14 are provided on the body 11 near its two first long sides 111. The two support structures 14 support the two tab groups respectively.

[0066] In this embodiment, by providing two support portions 141 and symmetrically distributing the two support portions 141 along the center line of the first through hole 13, the tab assembly can be subjected to symmetrical support forces from the support structure 14, thereby improving the stress state of the tab assembly, reducing the deformation of the tab during welding, and effectively increasing the contact area between the tab assembly and the pole post 22.

[0067] Please refer to Figure 8, which is an enlarged view of point B in Figure 7. In one embodiment, along the direction of the length dimension L, one end of each of the two support portions 141 is located on both sides of the first through hole 13, and along the direction of the width dimension W, the other end of each of the two support portions 141 is located between the adjacent first long side 111 and the first through hole 13. In this way, the support of the support portions 141 for the tab assembly can be improved, and the compactness of the various structural layouts on the lower plastic part 1 can be improved, so as to control the size of the lower plastic part 1 and thus effectively control the manufacturing cost.

[0068] Among them, the first through hole 13 is a rectangular hole, and when its corner is rounded, the part of the support part 141 opposite to the corner is an arc structure.

[0069] Referring to Figure 7, in one embodiment, a support structure 14 is provided on the body 11 near both first long sides 111. The first surface 12 also has two connecting portions 143. Along the direction of the length dimension L, the two connecting portions 143 are located on both sides of the first through hole 13. The two ends of the connecting portions 143 are connected to the adjacent support portions 141. This enhances the strength of the lower plastic part 1 around the first through hole 13, improving its deformation, and also allows the support structure 14 to support tabs with any angle of the cut edge, thus improving the adaptability of the support structure 14.

[0070] Please refer to Figure 9, which is a cross-sectional view of the support structure 14 provided in an embodiment of this application. In one embodiment, the support structure 14 protrudes from the first surface 12 at a height of H1, satisfying: 0.2mm ≤ H1 ≤ 1.2mm.

[0071] The height dimension H1 of the support structure 14 protruding from the first surface 12 includes, but is not limited to, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.62mm, 0.68mm, 0.7mm, 0.72mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 1mm, 1.1mm, and 1.2mm.

[0072] For example, the support structure 14 protrudes from the first surface 12 with a height dimension H1 of 0.7 mm.

[0073] In this embodiment, by limiting the height dimension H1 of the support structure 14 protruding from the first surface 12, on the one hand, it can be avoided that it is too small and its support for the tab assembly is not obvious, and on the other hand, it can be avoided that it is too large and the height dimension of the cell is too large, thereby improving the energy density of the cell.

[0074] Referring to Figure 7, in one embodiment, a connecting structure 15 is further protruding from the first surface 12. The connecting structure 15 is located on one side of the through hole and is configured to be thermally fused with the insulating film of the battery cell. In this way, it can effectively prevent the lower plastic part 1 from being melted through when it is thermally fused with the insulating film, thereby ensuring the insulation between the cover plate 21 and the internal components of the battery cell.

[0075] Optionally, the connecting structure 15 is located between the first through hole 13 and the first long side 111.

[0076] Please refer to Figure 10, which is a partial structural schematic diagram of the lower plastic part 1 provided in an embodiment of this application. In one embodiment, a reinforcing platform 17 is provided protrudingly on the first surface 12 near its periphery. The body 11 has a second surface 16 opposite to the first surface 12. A groove 18 is provided on the second surface 16 opposite to the reinforcing platform 17. Intersecting reinforcing ribs 19 are provided in the groove 18, and a plurality of drainage holes 181 are provided at the bottom of the groove 18.

[0077] Specifically, along the direction of the length dimension L, the two ends of the first surface 12 are provided with reinforcing platforms 17.

[0078] In this embodiment, by providing the reinforcing platform 17, the dimension of the reinforcing rib 19 in the thickness direction of the lower plastic part 1 can be enhanced, thereby increasing the strength of the lower plastic part 1 and improving the structural reliability of the cover plate assembly 2.

[0079] In addition, by setting drainage holes 181, during liquid injection, the electrode liquid can also flow into the area around the electrode assembly through these drainage holes, thereby improving the liquid injection efficiency.

[0080] It is understandable that, in addition to the drain hole 181, the body 11 is also provided with a drain hole at the position opposite to the injection hole of the cover plate 21, and an exhaust hole is provided at the position opposite to the explosion-proof valve.

[0081] Referring to Figure 2, in one embodiment, there are two pole posts 22 and two mounting holes, with each pole post 22 engaging with one of the two mounting holes. The lower plastic part 1 includes two bodies 11. The two bodies 11 are arranged side-by-side along the length dimension L. The first through holes 13 of each body 11 engage with the two pole posts 22. This allows for the separate assembly of the two bodies 11 during assembly, improving adjustability.

[0082] In some other embodiments, there are two pole posts 22 and two mounting holes. Each pole post 22 mates with one of the two mounting holes. The body 11 has two first through holes 13. There are two support structures 14. Each support structure 14 corresponds to one of the two first through holes 13, and each first through hole 13 mates with one of the two pole posts 22.

[0083] Referring to Figure 5, in one embodiment, the cover plate assembly 2 further includes a pressure block 23, an upper plastic component 24, and a sealing ring 25. The pressure block 23 is sleeved on one end of the pole post 22 opposite to the tab connection groove 221 and is located on one side of the cover plate 21. The upper plastic component 24 is sleeved on the pole post 22 and is located between the pressure block 23 and the cover plate 21. The sealing ring 25 is sleeved on the pole post 22 to seal between the pole post 22 and the cover plate 21.

[0084] It is understandable that the pressure block 23 is welded to the terminal post 22 to prevent the terminal post 22 from falling into the cell; the upper plastic part 24 insulates and isolates the pressure block 23 and the cover plate 21. Simultaneously, the upper plastic part 24 can also be partially located within the mounting hole to improve the insulation between the terminal post 22 and the cover plate 21. The sealing ring 25 prevents electrolyte leakage from the mounting hole.

[0085] Please refer to Figure 11, which is a schematic diagram of the structure of a battery cell provided in an embodiment of this application. Accordingly, an embodiment of this application provides a battery cell. The battery cell includes a housing 31, an electrode assembly 32, a tab assembly 33, and the aforementioned cover plate assembly 2. The housing 31 has a receiving cavity. The electrode assembly 32 is disposed within the receiving cavity. The cover plate assembly 2 covers the housing 31. One end of the tab assembly 33 is connected to the electrode assembly 32, and the other end is located in the tab connecting groove 221 and connected to the inner wall of the tab connecting groove 221.

[0086] In this embodiment, by adopting the cover plate assembly 2 provided in some embodiments of this application, on the one hand, the main body 222 can have a larger width dimension while ensuring the strength of the cover plate 21 in the width direction; on the other hand, not only can the pole post 22 have a larger length dimension to improve the current carrying capacity of the pole post 22, but also the length dimension a' of the main body 222 can be avoided from being too large and affecting the arrangement of other components on the cover plate 21, and the strength of the cover plate 21 in the length direction can be guaranteed.

[0087] Lithium-ion batteries, with their advantages of light weight and good safety performance, are widely used in fields such as electric vehicles. The tabs are a key component of the battery cell; the positive tab 1a is generally made of aluminum, while the negative tab 2a is generally made of copper. In the battery cell 3, the tabs are connected to the electrode plates and terminals, respectively, and are the carriers of the current output from the cell. During use, if the current-carrying capacity of the positive and negative electrodes of the battery cell 3 is inconsistent, it may lead to a decrease in the performance and lifespan of the cell, and increase safety risks. Therefore, the connection structure of the tabs is particularly important.

[0088] In view of the above, this application also provides the following embodiments to improve the consistency of the current overcurrent capability of the positive and negative electrodes of the battery cell 3.

[0089] Referring to Figure 12, this application provides a battery cell. The terminal post 22 includes a positive terminal post and a negative terminal post, and the electrode assembly 33 includes a positive electrode tab 1a and a negative electrode tab 2a. The positive electrode tab 1a has a positive electrode tab 11a, which is connected to the positive terminal post. The positive electrode tab 1a is connected to the electrode assembly 32. The negative electrode tab 2a has a negative electrode solder area 21a, which is connected to the negative terminal post. The negative electrode tab 2a is connected to the electrode assembly 32. The area of ​​the positive electrode tab 11a is larger than the area of ​​the negative electrode solder area 21a. Therefore, the current carrying capacity of the positive electrode tab 1a is weaker than that of the negative electrode tab 2a. By making the area of ​​the positive electrode tab 11a larger than that of the negative electrode solder area 21a, the current carrying capacity between the positive electrode tab 1a and the negative electrode tab 2a can be balanced, ensuring the stability of the output current of the battery cell 3 and achieving a balanced distribution of current between the positive and negative electrodes. This structure not only improves the overall performance of the battery cell and provides a more stable power supply, but also extends the service life of the battery cell 3.

[0090] In some embodiments, the positive electrode tab 1a is a first metal, and the negative electrode tab 2a is a second metal, wherein the conductivity of the first metal is less than that of the second metal. Specifically, during the charging and discharging process of the battery cell, the flow of current places higher demands on the conductivity of the positive electrode tab 1a and the negative electrode tab 2a to better carry the current output by the battery cell. Based on the difference in conductivity between the positive electrode tab 1a and the negative electrode tab 2a, this application improves the current carrying capacity of the positive electrode tab 1a by setting the area of ​​the positive electrode tab 11a to be larger than that of the negative electrode solder area 21a, thereby ensuring that the positive electrode can effectively handle its current demand during the charging and discharging process of the battery cell 3 and reducing performance degradation caused by current overload. In the embodiments of this application, by increasing the area of ​​the positive electrode tab 11a, the conductive area of ​​the positive electrode tab 1a is also increased, thereby improving its current carrying capacity and ensuring that the positive electrode of the battery cell 3 can effectively handle its current demand during the charging and discharging process. In addition, this area setting helps to balance the current distribution inside the battery, avoid uneven internal temperature of cell 3 caused by uneven current carrying of positive and negative electrodes, or cause local temperature rise, thereby reducing the risk of thermal runaway, improving the reliability of cell 3, and extending the service life of cell 3.

[0091] Specifically, the positive electrode tab 1a can be made of aluminum, and the negative electrode tab 2a can be made of copper. Both aluminum and copper possess excellent electrical conductivity and chemical stability. First, aluminum has a relatively low manufacturing cost, which helps reduce the overall production cost of the battery, significant for large-scale production and market promotion. Furthermore, aluminum has a lower density than copper; using aluminum as the positive electrode tab 1a reduces the battery's weight, which is particularly important for applications such as portable electronic devices and electric vehicles, as it helps improve the battery's energy density and range. In terms of performance, although aluminum has a lower conductivity than copper, its excellent corrosion resistance is crucial for extending battery life. A dense aluminum oxide film can form on the aluminum surface, effectively preventing corrosion and ensuring stable battery operation in harsh environments. On the other hand, the use of copper for the negative electrode tab 2a is based on copper's superior electrical conductivity. Copper has a higher conductivity than aluminum, meaning that in the negative electrode tab 2a, copper can conduct current more efficiently, which is crucial for the cell's performance at high current densities. Copper's properties enable the negative electrode tab 2a to withstand a larger current load, thus meeting the performance requirements of the battery cell under high power output demands. Therefore, the design of using aluminum for the positive electrode tab 1a and copper for the negative electrode tab 2a not only achieves a balance between cost and performance but also improves the safety, durability, and environmental friendliness of the battery cell 3.

[0092] In some embodiments, the area of ​​the positive electrode tab 11a is a first area. The area of ​​the negative electrode solder area 21a is a second area. The ratio of the first area to the second area is greater than 1.01 and less than or equal to 1.2. Therefore, by setting the ratio of the first area to the second area between 1.01 and 1.2, current distribution can be optimized, and the difference in current overcurrent capacity between the positive electrode tab 1a and the negative electrode tab 2a can be compensated. This helps maintain the stability of the battery output current, reduces performance degradation and thermal management problems caused by uneven current, and thus improves the overall performance and lifespan of the cell 3. In some examples, the ratio of the first area to the second area can be any ratio among 1.04, 1.06, 1.08, 1.1, and 1.2.

[0093] Referring to Figure 13, in some embodiments, the area of ​​the positive electrode tab 1a is larger than the area of ​​the negative electrode tab 2a. Specifically, the area of ​​the positive electrode tab 1a is designed to be larger than the area of ​​the negative electrode tab 2a, thereby providing a larger area for the positive electrode tab 1a, so that the positive electrode tab 1a can also be set to a larger area. This allows the positive electrode tab 1a to more effectively carry the current during the charging and discharging process, thereby improving the overall performance and reliability of the battery cell 3.

[0094] In some examples, the width of the positive electrode tab 1a can be larger than that of the negative electrode tab 2a, as shown in Figure 13. The width of the positive electrode tab 1a can be d1, and the width of the negative electrode tab 2a can be d2, where d1 > d2.

[0095] In some embodiments, the area of ​​the positive electrode tab 1a is a third area, and the area of ​​the negative electrode tab 2a is a fourth area. The ratio between the third area and the fourth area is greater than 1 and less than or equal to 1.18. In some examples, the ratio between the third area and the fourth area can be any ratio among 1.0, 1.08, 1.1, 1.15, and 1.18.

[0096] In some embodiments, the battery cell 3 further includes a positive electrode connecting piece and a negative electrode connecting piece. The positive electrode connecting piece is connected to the positive electrode tab 11a and the positive electrode post, respectively. The negative electrode connecting piece is connected to the negative electrode solder area 21a and the negative electrode post, respectively. Specifically, the tab connecting piece is a component used to lead out current. In this embodiment, the positive electrode connecting piece can be soldered to the positive electrode tab 11a and the positive electrode post, and the negative electrode connecting piece can be soldered to the negative electrode solder area 21a and the negative electrode post, respectively, to ensure the continuity and stability of the internal circuitry of the battery.

[0097] In other embodiments, the positive electrode tab 11a is directly welded to the positive electrode post. The negative electrode solder area 21a is directly welded to the negative electrode post. Therefore, in this embodiment, no electrode adapter piece is required within the cell 3. First, eliminating the electrode adapter piece installation step greatly simplifies the cell manufacturing process. The traditional cell 3 manufacturing process involves multiple complex steps; simplification makes the production process more direct and efficient. This not only reduces production time but also lowers production costs. Second, the absence of an electrode adapter piece reduces material usage. As an electronic component, the electrode adapter piece requires material resources for its production and installation. By eliminating this component, material waste during cell 3 manufacturing can be significantly reduced, which is of great significance for environmental protection and resource conservation. Furthermore, the presence of an electrode adapter piece can become a potential point of failure; this design, by directly connecting the tab and the internal electrode, reduces connection points, thereby reducing the risk of cell 3 malfunctioning during use. This makes the cell 3 manufacturing process simpler and more material-efficient.

[0098] Referring to Figures 15 and 16, in some embodiments, the area of ​​the positive electrode tab 11a is positively correlated with the capacity or volume of the battery cell 3. Therefore, a larger capacity or volume of the battery cell 3 results in a larger current flow rate for the positive electrode tab 1a. Specifically, as the capacity of the battery cell 3 increases, its volume also increases accordingly. Furthermore, to make the structure of the battery cell 3 more compact and avoid redundant space within it, an increase in the volume of the battery cell 3 typically leads to an increase in its capacity. Accordingly, either the area of ​​the positive electrode tab 11a is positively correlated with the capacity of the battery cell 3, or the area of ​​the positive electrode tab 11a is positively correlated with the volume of the battery cell 3.

[0099] In some embodiments, the area of ​​the positive electrode tab 11a and the capacity or volume of the battery cell 3 can be set to the following values: when 50Ah ≤ capacity of battery cell 3 < 150Ah or 700cm³ ≤ volume of battery cell 3 < 2000cm³, 60mm² ≤ area of ​​positive electrode tab 11a < 80mm²; when 150Ah ≤ capacity of battery cell 3 < 250Ah or 2000cm³ ≤ volume of battery cell 3 < 2400cm³, 80mm² ≤ area of ​​positive electrode tab 11a < 100mm²; when 250Ah ≤ capacity of battery cell 3 < 350... When the capacity of cell 3 is less than 3000cm³ or 2400Ah, the area of ​​the positive electrode tab 11a is less than 120mm²; when the capacity of cell 3 is less than 500Ah or 3000cm³ is less than 4000cm³, the area of ​​the positive electrode tab 11a is less than 80mm²; when the capacity of cell 3 is less than 700Ah or 4000cm³ is less than 6000cm³, the area of ​​the positive electrode tab 11a is less than 190mm².

[0100] In some examples, the values ​​of the positive electrode tab 11a area, the capacity of the cell 3 and the volume of the cell 3 can all fluctuate within a range of 4%, which can minimize their impact on the performance of the cell 3.

[0101] In some embodiments, the ratio between the area of ​​the positive electrode tab 11a and the area of ​​the negative electrode tab 2a is greater than or equal to 5% and less than or equal to 11%. Thus, the area of ​​the positive electrode tab 11a relative to the negative electrode tab 2a is controlled within a suitable ratio, ensuring sufficient connection between the battery terminals and the positive electrode tab 11a, guaranteeing effective electrical conduction, while avoiding material waste and structural imbalance caused by excessive area. This ratio control is crucial in the manufacturing of the battery cell 3, as it not only optimizes the performance of the battery cell 3, improving energy efficiency and cycle life, but also enhances the stability and safety of the battery cell 3 under extreme operating conditions, ensuring the overall reliability of the battery cell 3.

[0102] In other embodiments, the ratio between the area of ​​the negative electrode solder area 21a and the area of ​​the negative electrode tab 2a is greater than or equal to 5% and less than or equal to 12%. Thus, the area of ​​the negative electrode solder area 21a relative to the area of ​​the negative electrode tab 2a is controlled within a suitable proportion, ensuring sufficient connection between the electrode post and the negative electrode solder area 21a for effective electrical conduction, while avoiding material waste and structural imbalance due to excessive area. This proportion control is crucial in the manufacturing of the battery cell 3, as it not only optimizes the performance of the battery cell 3, improving energy efficiency and cycle life, but also enhances the stability and safety of the battery cell 3 under extreme operating conditions, ensuring the overall reliability of the battery cell.

[0103] Referring to Figure 14, in some embodiments, the battery cell 3 further includes an electrode assembly 33, with a positive electrode tab 1a connected to the electrode assembly 33 and a negative electrode tab 2a connected to the electrode assembly 33; the positive electrode tab 11a is spaced apart from the electrode assembly 33. This distance between the positive electrode tab 11a and the electrode assembly 33 ensures that the welding tool can operate safely during the welding process, effectively preventing interference between the positive electrode tab 11a and the electrode assembly 33, and reducing the risk of damage to the electrode assembly 33 or the welding tool due to collisions with the welding tool.

[0104] Referring to Figure 14, in some examples, the distance between the positive electrode tab 11a and the electrode assembly 33 can be set to L, and the value of L can be between 10 mm and 20 mm. In other examples, the distance between the negative electrode solder area 21a and the electrode assembly 33 can also be between 10 mm and 20 mm.

[0105] In some embodiments, the negative electrode soldering area 21a is spaced apart from the electrode assembly 33. This distance ensures safe operation of the welding tool during the welding process, effectively preventing interference between the negative electrode tab 2a and the electrode assembly 33, and reducing the risk of damage to the electrode assembly 33 or the welding tool due to collisions. In related technologies, the electrode assembly 33 is also referred to as a core package, coil, or cell body, and typically includes a positive electrode sheet, a negative electrode sheet, a positive electrode material, a negative electrode material, and a separator. The electrode assembly 33 can be formed by winding or stacking and is a key structure of the cell.

[0106] Accordingly, embodiments of this application also provide a battery, which includes a housing assembly and the aforementioned battery cell 3. The housing assembly has a mounting cavity. There are multiple battery cells 3, which are disposed in the mounting cavity and are connected in series and / or in parallel.

[0107] In this embodiment, by adopting the battery cell 3 provided in some embodiments of this application, not only can its overcurrent capacity be improved, but also the structural strength can be guaranteed, thereby improving the reliability of the battery.

[0108] Furthermore, in the embodiments of this application, the current-carrying capacity of the positive electrode tab 1a is weaker than that of the negative electrode tab 2a. The area of ​​the positive electrode tab 11a is set to be larger than that of the negative electrode solder area 21a, thereby balancing the current-carrying capacity between the positive electrode tab 1a and the negative electrode tab 2a, ensuring the stability of the output current of the cell 3, and achieving a balanced distribution of current between the positive and negative electrodes. Thus, this structure not only improves the overall performance of the battery and provides a more stable power supply, but also extends the battery's lifespan.

[0109] The technical solution and effects of this application will be described in detail below through specific embodiments. The following embodiments are only some embodiments of this application and are not intended to limit the application in any specific way. This embodiment aims to examine the strength of the cover plate 21 and the current-carrying capacity of the pole 22.

[0110] The specific details of the test content for the embodiments are as follows.

[0111] I. Test-related instructions

[0112] (a) Relevant parameters of the test object

[0113] 1. Cover plate 21

[0114] Material of cover plate 21: aluminum alloy;

[0115] The width dimension W of cover plate 21 is 36mm;

[0116] The length of cover plate 21 is L = 175 mm;

[0117] The thickness of cover plate 21 is D=2mm.

[0118] 2. Pole Column 22

[0119] Material of pole 22: Aluminum;

[0120] The height of pole 22 is h = 3.2 mm.

[0121] Width dimension b' = 30mm;

[0122] The length dimension a' is 30 / 0.9~30 / 0.4=33.3~75mm.

[0123] Test groups 1, 2, 3 and 4 were selected in sequence with a' values ​​of 33.3 mm, 45 mm, 60 mm and 75 mm.

[0124] (II) Control Group

[0125] Except for the length dimension a' of the pole post 22 and the length of the mounting hole on the cover plate 21 corresponding to the length dimension a', the parameters of control groups 1, 2 and 3 are the same as those of the test group.

[0126] II. Test Results

[0127] The pressure resistance of the cover plate 21 and the flow capacity of the pole 22 were tested in both the test group and the control group. The test data are shown in the table below:

[0128]

[0129] Table 1. Test Comparison Table

[0130] As shown in Table 1, given a fixed width b' of the pole post 22, a larger length a' results in a stronger flow capacity of the pole post 22. However, a larger length a' also leads to a weaker pressure-bearing capacity of the cover plate 21. Furthermore, a larger length a' of the pole post 22 affects the arrangement of the explosion-proof valve mounting holes and injection holes on the cover plate 21, increasing design and manufacturing complexity. Therefore, the cover plate assembly 2 provided in this embodiment ensures both the flow capacity of the pole post 22 and the strength of the cover plate 21, giving the cover plate 21 a suitable pressure-bearing capacity.

Claims

1. A cover plate assembly (2), comprising: The cover plate (21) is provided with mounting holes, and the cover plate (21) has a width dimension W and a length dimension L; The pole post (22) includes a main body (222), one end of which is provided with a pole tab connecting groove (221). The main body (222) is inserted into the mounting hole. Along the direction of the width dimension W, the main body (222) has a width dimension b' and along the direction of the length dimension L, the main body (222) has a length dimension a'. Where W-6mm≤b'≤W-8mm, and 0.4≤b' / a'≤0.

9.

2. The cover plate assembly (2) according to claim 1, wherein Along the direction of the width dimension W, the tab connecting groove (221) has a width dimension d, and along the direction of the length dimension L, the tab connecting groove (221) has a length dimension c, satisfying: 0.4≤d / c≤0.

9.

3. The cover plate assembly (2) according to claim 2, wherein d / c=b' / a'.

4. The cover plate assembly (2) according to claim 2 or 3, wherein The thickness of the groove wall of the tab connection groove (221) is D, which satisfies: 0.8mm≤D≤1.5mm.

5. The cover plate assembly (2) according to any one of claims 1-4, wherein, The electrode post (22) further includes a flange (223), the electrode post (22) having a first end (224) configured to face the electrode assembly (32) of the cell, the flange (223) being disposed on the outer peripheral surface of the body (222) and adjacent to the first end (224), the flange (223) engaging with the cover plate (21).

6. The cover plate assembly (2) according to claim 5, wherein The flange (223) extends in a ring shape along the circumference of the pole (22).

7. The cover plate assembly (2) according to claim 6, wherein Along the direction of the width dimension W, the outer edge of the flange (223) has a width dimension b, and along the direction of the length dimension L, the outer edge of the flange (223) has a length dimension a, satisfying: 0.4≤a / b≤0.

9.

8. The cover plate assembly (2) according to claim 7, wherein a / b = b' / a'.

9. The cover plate assembly (2) according to any one of claims 5-8, wherein, Along the radial direction of the mounting hole, the flange (223) has a width dimension e, satisfying 1.5mm≤e≤2mm.

10. The cover plate assembly (2) according to any one of claims 1-9, the cover plate assembly (2) further includes a lower plastic part (1), the lower plastic part (1) includes a body (11), one side of the body (11) is connected to one side of the cover plate (21), the body (11) is provided with a first through hole (13), and the main body (222) is also disposed through the first through hole (13).

11. The cover plate assembly (2) according to claim 10, wherein The body (11) has a first surface (12) facing away from the cover plate (21), and a support structure (14) is provided protruding outward from the first surface (12). The support structure (14) is disposed adjacent to the pole post (22), and the support structure (14) is configured to abut against the tab of the battery cell along the axis of the mounting hole.

12. The cover plate assembly (2) according to claim 11, wherein The body (11) has two first long sides (111) parallel to the direction of the length dimension L, and the support structure (14) is provided at least on the body (11) near one of the first long sides (111); the support structure (14) includes two support parts (141), which are symmetrically distributed along the axis of the first through hole (13).

13. The cover plate assembly (2) according to claim 12, wherein Along the direction of the length dimension L, one end of each of the two support portions (141) is located on both sides of the first through hole (13), and along the direction of the width dimension W, the other end of each of the two support portions (141) is located between the adjacent first long side (111) and the first through hole (13).

14. The cover plate assembly (2) according to claim 12 or 13, wherein The support structure (14) is provided on the body (11) near the two first long sides (111), and the first surface (12) is also provided with two connecting parts (143). Along the direction of the length dimension L, the two connecting parts (143) are respectively located on both sides of the first through hole (13); the two ends of the connecting parts (143) are respectively connected to the adjacent support parts (141).

15. The cover plate assembly (2) according to any one of claims 11-14, wherein, The height dimension of the support structure (14) protruding from the first surface (12) is H1, which satisfies: 0.2mm≤H1≤1.2mm.

16. The cover plate assembly (2) according to any one of claims 11-15, wherein, A reinforcing platform (17) is provided on the part of the first surface (12) near its periphery.

17. The cover plate assembly (2) according to claim 16, wherein The body (11) has a second surface (16) opposite to the first surface (12). The second surface (16) is provided with a groove (18) at the part opposite to the reinforcing platform (17). The groove (18) is provided with crisscrossing reinforcing ribs (19). The bottom of the groove (18) is provided with a plurality of drainage holes (181).

18. The cover plate assembly (2) according to any one of claims 11-17, wherein, There are two pole posts (22) and two mounting holes, and the two pole posts (22) respectively mate with the two mounting holes; in, The lower plastic part (1) includes two bodies (11). Along the direction of the length dimension L, the two bodies (11) are arranged side by side, and the first through holes (13) of the two bodies (11) respectively cooperate with the two pole posts (22). or, The main body (11) is provided with two first through holes (13), and there are two support structures (14). The two support structures (14) are respectively provided in correspondence with the two first through holes (13), and the two first through holes (13) are respectively engaged with the two pole posts (22).

19. The cover plate assembly (2) according to any one of claims 1-18, the cover plate assembly (2) further includes a pressure block (23), an upper plastic part (24) and a sealing ring (25), the pressure block (23) is sleeved on one end of the pole post (22) away from the pole ear connecting groove (221) and located on one side of the cover plate (21), the upper plastic part (24) is sleeved on the pole post (22) and located between the pressure block (23) and the cover plate (21), and the sealing ring (25) is sleeved on the pole post (22) to seal between the pole post (22) and the cover plate (21).

20. A battery cell (3), comprising: The housing (31) has a receiving cavity; An electrode assembly (32) is disposed within the receiving cavity; The cover assembly (2) as described in any one of claims 1-19, covers the housing (31); The tab assembly (33) has one end connected to the electrode assembly (32) and the other end located in the tab connection groove (221) and connected to the inner wall of the tab connection groove (221).

21. The electric cell (3) according to claim 20, wherein The electrode post (22) includes a positive electrode post and a negative electrode post, and the electrode tab assembly (33) includes: A positive electrode tab (1a) is provided with a positive electrode solder area (11a), which is connected to the positive electrode post; the positive electrode tab (1a) is connected to the electrode assembly (32); The negative electrode tab (2a) is provided with a negative electrode solder area (21a), which is connected to the negative electrode post; the negative electrode tab (2a) is connected to the electrode assembly (32); Wherein, the positive electrode tab (1a) is a first metal, the negative electrode tab (2a) is a second metal, the conductivity of the first metal is less than the conductivity of the second metal, and the area of ​​the positive electrode solder area (11a) is greater than the area of ​​the negative electrode solder area (21a).

22. The electric cell (3) according to claim 21, wherein The area of ​​the positive electrode solder area (11a) is a first area, and the area of ​​the negative electrode solder area (21a) is a second area. The ratio of the first area to the second area is greater than 1.01 and less than or equal to 1.

2.

23. The electric cell (3) according to claim 21 or 22, wherein The area of ​​the positive electrode tab (1a) is larger than the area of ​​the negative electrode tab (2a).

24. The electric cell (3) according to any one of claims 21-23, wherein, The area of ​​the positive electrode tab (1a) is the third area, and the area of ​​the negative electrode tab (2a) is the fourth area; The ratio between the third area and the fourth area is greater than 1 and less than or equal to 1.

18.

25. The battery cell (3) according to any one of claims 21-24, wherein the battery cell further comprises a positive electrode connecting piece and a negative electrode connecting piece; The positive electrode connecting piece is connected to the positive electrode solder area (11a) and the positive electrode post respectively, and the negative electrode connecting piece is connected to the negative electrode solder area (21a) and the negative electrode post respectively.

26. The electric cell (3) according to any one of claims 21-25, wherein, The positive electrode solder area (11a) is directly soldered to the positive electrode post; The negative electrode solder area (21a) is directly soldered to the negative electrode post.

27. The electric cell (3) according to any one of claims 21-26, wherein, The area of ​​the positive electrode solder area (11a) is positively correlated with the capacity or volume of the battery cell.

28. The electric cell (3) according to any one of claims 21-27, wherein, The ratio between the area of ​​the positive electrode solder pad (11a) and the area of ​​the negative electrode tab (2a) is greater than or equal to 5% and less than or equal to 11%; and / or, The ratio between the area of ​​the negative electrode solder area (21a) and the area of ​​the negative electrode solder area (21a) is greater than or equal to 5% and less than or equal to 12%.

29. The electric cell (3) according to any one of claims 21-28, wherein, The positive electrode soldering area (11a) is spaced apart from the cell body (3a), and / or the negative electrode soldering area (21a) is spaced apart from the cell body (3a).

30. A battery comprising: The housing assembly has a mounting cavity; And, in any one of claims 20-29, there are multiple battery cells (3), multiple battery cells (3) are disposed in the mounting cavity, and the multiple battery cells (3) are connected in series and / or in parallel.

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