Top cover assembly, single battery cell and battery pack

Abstract

The utility model relates to the technical field of batteries, and provides a top cover assembly, a single battery cell and a battery pack. The top cover assembly comprises a cover plate and a sealing piece. And the cover plate is provided with a liquid injection hole. And the hole wall surface of the liquid injection hole is provided with an internal thread. The sealing piece comprises a connecting part. The connecting part comprises at least two connecting sections arranged at intervals in the circumferential direction of the connecting part. And each connecting section is provided with an external thread matched with the internal thread. Wherein the connecting part is in threaded connection in the liquid injection hole, and the hole diameter of at least part of the hole section of the liquid injection hole is smaller than the outer diameter of the connecting part. Therefore, the sealing element can be prevented from falling off from the liquid injection hole or falling into the single battery due to extrusion of the shell of the single battery, and the sealing performance of the single battery in long-term use is ensured.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a top cover assembly, a single battery cell, and a battery pack. Background Technology

[0002] In related technologies, after the electrolyte filling of a single battery cell is completed, the filling hole on the cover plate is sealed with sealant pins, and an aluminum sheet is welded to the surface of the cover plate to ensure that the filling hole is sealed. However, during the production, handling, and cleaning of the single battery cell, the sealant pins may be squeezed out of the filling hole or fall into the casing due to the casing being squeezed. Both of these situations can adversely affect the safety and formation of the battery. In addition, the welding quality also directly affects the sealing effect of the filling hole. If defects such as weld seams, craters, or incomplete welds occur during the welding process, the single battery cell will need to be repaired, reducing the production quality. Utility Model Content

[0003] The present invention provides a top cover assembly, a single battery cell, and a battery pack. The sealing element is installed in the liquid injection hole by means of a threaded connection. After the sealing element is fixed, it can prevent the sealing element from falling into the single battery cell and also prevent the sealing element from falling off from the liquid injection hole, thus ensuring the sealing performance for long-term use and at least partially solving the above-mentioned technical problems.

[0004] In a first aspect, embodiments of the present invention provide a top cover assembly, comprising:

[0005] The cover plate is provided with an injection hole, and the wall surface of the injection hole is provided with internal threads;

[0006] A sealing element includes a connecting portion, the connecting portion comprising at least two connecting segments spaced apart circumferentially thereon, each of the connecting segments being provided with an external thread that matches the internal thread;

[0007] The connecting part is threaded into the injection hole, and the diameter of at least a portion of the injection hole is smaller than the outer diameter of the connecting part.

[0008] In one embodiment, along the first direction, the injection hole has a tapered section with a decreasing inner diameter, the larger end of the tapered section having a diameter of D1, and the outer diameter of the connecting portion having a diameter of D2, satisfying: D1≤D2.

[0009] In one embodiment, the tapered section is set to be conical, and the inclination angle of the generatrix of the tapered section is α, satisfying: 5°≤α≤45°.

[0010] In one embodiment, along the first direction, each of the connecting segments is inclined toward the axis of the connecting portion, and the inclination angle is β, satisfying: β < α.

[0011] In one embodiment, a gap is formed between every two adjacent connecting segments, wherein the sum of the arc lengths of all the gaps along the circumference of the connecting portion is L1, and the sum of the arc lengths of all the connecting segments is L2, satisfying: 0.25≤L1 / L2≤1.

[0012] In one embodiment, the seal further includes:

[0013] The main body is connected to the connecting part;

[0014] A sealing part is fitted onto the main body, the sealing part is located inside the injection hole, and the outer peripheral surface of the sealing part abuts against the hole wall surface of the injection hole.

[0015] In one embodiment, the injection port includes:

[0016] The first hole section has the internal thread provided on its hole wall surface;

[0017] The second hole segment is connected to the side of the first hole segment closest to the outside, wherein the diameter of the second hole segment is larger than the diameter of the first hole segment;

[0018] The connecting part is connected to the first hole segment, the main body part is disposed in the second hole segment, and the outer peripheral surface of the sealing part abuts against the hole wall surface of the second hole segment.

[0019] In one embodiment, the length of the connecting portion is L3 and the length of the main body portion is L4, satisfying: 1≤L3 / L4≤4.

[0020] Secondly, embodiments of this utility model provide a single battery cell, including the top cover assembly as described above.

[0021] Thirdly, embodiments of this utility model provide a battery pack, including the single battery cell as described above.

[0022] The beneficial effects of the embodiments of this utility model are as follows:

[0023] In embodiments of this invention, by forming a threaded connection between the seal and the injection hole, the seal can be prevented from detaching from the injection hole or falling into the cell due to compression of the cell casing, ensuring the long-term sealing performance of the cell. Since the connecting portion of the seal includes at least two circumferentially spaced connecting segments, when the connecting segments are threadedly connected to the injection hole, because the diameter of at least a portion of the injection hole is smaller than the outer diameter of the connecting portion, the injection hole will compress and deform each connecting segment from its outer circumferential surface to its interior. This deformation will exert a force on the hole wall of the injection hole, improving the reliability of the connection between the connecting segments and the injection hole. Therefore, it also prevents the seal from detaching from the injection hole due to vibration of the cell, improving the reliability of the connection between the seal and the injection hole of the cover plate. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the top cover assembly provided in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of the sealing element provided in an embodiment of this utility model;

[0027] Figure 3 This is a cross-sectional view of the sealing element provided in an embodiment of this utility model when it is assembled into the injection hole;

[0028] Figure 4 This is one of the structural schematic diagrams of the main body and connecting part provided in the embodiment of this utility model;

[0029] Figure 5 This is a second structural schematic diagram of the main body and connecting part provided in an embodiment of this utility model;

[0030] Figure 6 This is a cross-sectional view of the cover plate at the injection hole provided in an embodiment of this utility model.

[0031] Figure label:

[0032] 10-Cover plate, 110-Injection hole, 1110-Gradual narrowing section, 1120-First hole section, 1130-Second hole section, 120-Internal thread, 20-Seal, 210-Connecting part, 2110-Connecting section, 2120-External thread, 2130-Notch, 220-Main body, 230-Sealing part, 240-End, 2410-Groove. Detailed Implementation

[0033] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of the present utility model and are not intended to limit the present utility model. In the present utility model, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0034] like Figures 1 to 6 As shown, this application embodiment provides a top cover assembly. The top cover assembly includes a cover plate 10 and a sealing member 20. The cover plate 10 has an injection hole 110. The wall surface of the injection hole 110 has an internal thread 120. The sealing member 20 includes a connecting portion 210. The connecting portion 210 includes at least two connecting segments 2110 spaced apart circumferentially therefrom. Each connecting segment 2110 has an external thread 2120 that matches the internal thread 120. The connecting portion 210 is threadedly connected to the injection hole 110, and the diameter of at least a portion of the injection hole 110 is smaller than the outer diameter of the connecting portion 210.

[0035] In this embodiment, by forming a threaded connection between the seal 20 and the injection hole 110, the seal 20 can be prevented from detaching from the injection hole 110 or falling into the cell due to compression of the cell casing, ensuring the long-term sealing performance of the cell. Since the connecting portion 210 of the seal 20 includes at least two circumferentially spaced connecting segments 2110, when the connecting segments 2110 are threadedly connected to the injection hole 110, because the diameter of at least a portion of the injection hole 110 is smaller than the outer diameter of the connecting portion 210, the injection hole 110 will compress and deform each connecting segment 2110 from its outer circumferential surface to its interior. This deformation will exert a force on the hole wall of the injection hole 110, improving the reliability of the connection between the connecting segments 2110 and the injection hole 110. Therefore, it also prevents the seal 20 from detaching from the injection hole 110 due to vibration of the cell, improving the reliability of the connection between the seal 20 and the injection hole 110 of the cover plate 10.

[0036] It should be noted that when the connecting part 210 of the seal 20 is fully installed in the injection hole 110, two adjacent connecting sections 2110 can fit together exactly, or two adjacent connecting sections 2110 can still be spaced apart.

[0037] In some embodiments, the diameter of the injection hole 110 near the outer surface of the cover plate 10 may be greater than or equal to the outer diameter of the connecting portion 210 to ensure that the connecting portion 210 can be threaded into the injection hole 110. The diameter of the injection hole 110 near the inner surface of the cover plate 10 is smaller than the outer diameter of the connecting portion 210 so that the connecting portion 210 can be compressed and deformed by this portion, thereby increasing the friction between the connecting portion 2110 and the hole wall of the injection hole 110, thereby enhancing the connection strength between the seal 20 and the injection hole 110 and ensuring the reliable installation of the seal 20.

[0038] In some embodiments, the connecting portion 210 is made of a metal material to give it a certain rigidity. When the injection hole 110 causes each connecting segment 2110 to deform, each connecting segment 2110 has a certain ability to resist deformation, thereby enabling each connecting segment 2110 to apply a certain force to the hole wall surface of the injection hole 110, thereby increasing the friction between the connecting segment 2110 and the hole wall surface of the injection hole 110 and improving the connection strength of the seal 20.

[0039] In this embodiment, the sealing element 20 is installed using a threaded connection, replacing the traditional sealing structure that uses sealing nails and external welding. This simplifies the sealing process of the injection hole 110, eliminating the need for welding and preventing variations in the sealing performance of individual cells due to differences in welding quality. Furthermore, the threaded connection allows for detachable installation. When prolonged use of the individual cell causes electrolyte depletion or gas buildup leading to casing expansion, the sealing element 20 can be removed to replenish electrolyte or release reactive gases, thereby extending the cell's lifespan and improving its safety.

[0040] like Figure 5 and Figure 6 As shown, in some embodiments, along the first direction, the injection hole 110 has a tapered section 1110 with a decreasing inner diameter. The diameter of the larger end of the tapered section 1110 is D1, and the outer diameter of the connecting portion 210 is D2, satisfying: D1≤D2.

[0041] Understandably, since the injection hole 110 has a tapered section 1110, the inner diameter of the injection hole 110 gradually decreases along the first direction. As the connecting part 210 is gradually installed in the injection hole 110, the connecting part 210 will be gradually compressed by the injection hole 110, so that the gap 2130 of each connecting part 2110 on the side away from the main body 220 is reduced. Since the deformation of the connecting part 2110 will apply a force to the hole wall of the injection hole 110, the friction between the connecting part 2110 and the hole wall of the injection hole 110 will be greater. Furthermore, based on the threaded connection between the connecting part 2110 and the injection hole 110, reliable installation of the seal 20 can be ensured, preventing the seal 20 from falling off due to shaking, vibration, or other reasons.

[0042] In this embodiment of the application, the diameter of the larger end of the tapered section 1110 is less than or equal to the outer diameter of the connecting part 210, so that the connecting part 210 is gradually screwed into the injection hole 110 and will inevitably be compressed and deformed by the injection hole 110.

[0043] For example, the diameter of the larger end of the tapered section 1110 is equal to the outer diameter of the connecting part 210.

[0044] For example, the diameter of the larger end of the tapered section 1110 is smaller than the outer diameter of the connecting part 210. In this case, when installing the seal 20, a certain force can be applied to the connecting part 210 to tilt each connecting section 2110 toward its center, so as to ensure that the connecting part 210 can be installed in the injection hole 110.

[0045] Please continue reading. Figure 6 In some embodiments, the tapered section 1110 is tapered. The inclination angle of the generatrix of the tapered section 1110 is α, which satisfies: 5°≤α≤45°.

[0046] Understandably, if the inclination angle of the generatrix of the tapered section 1110 is less than 5°, the degree of deformation of each connecting section 2110 caused by the tapered section 1110 is small, resulting in a poor improvement in the friction between the connecting section 2110 and the wall surface of the injection hole 110. If the inclination angle of the generatrix of the tapered section 1110 is greater than 45°, the degree of deformation of each connecting section 2110 caused by the tapered section 1110 is too large, which may cause the connecting section 2110 to break, resulting in the seal 20 being unable to form an effective connection with the injection hole 110. An inclination angle of the generatrix of the tapered section 1110 greater than 45° may also cause the diameter of the smaller end of the tapered section 1110 to be too small, making it impossible for the connecting part 210 to be screwed to the smaller end of the tapered section 1110, resulting in a poor connection effect.

[0047] For example, the inclination angle of the busbar of the tapering segment 1110 is set to 5°, 15°, 25°, 35°, 45°, or any value between the two.

[0048] Please continue reading. Figure 4and Figure 6 In some embodiments, along the first direction, each connecting segment 2110 is inclined toward the axis of the connecting portion 210, and the inclination angle is β, satisfying: β < α.

[0049] Understandably, since each connecting segment 2110 is inclined towards the axis of the connecting portion 210, the connecting portion 210 formed by at least two connecting segments 2110 is also tapered. At this time, the shape of the connecting portion 210 matches the shape of the injection hole 110, facilitating the threaded installation of the connecting portion 210 into the injection hole 110. Since the inclination angle of the connecting segment 2110 is smaller than the inclination angle of the generatrix of the tapered section 1110, when the connecting portion 210 is positioned on the tapered section 1110, the tapered section 1110 can also drive each connecting segment 2110 to deform towards the axis of the connecting portion 210, thereby increasing the friction between the connecting segment 2110 and the wall surface of the injection hole 110.

[0050] It should be noted that when the connecting part 210 is also set to be tapered, the outer diameter of the larger end of the connecting part 210 is smaller than the aperture of the larger end of the tapered section 1110; and / or, the outer diameter of the smaller end of the connecting part 210 is smaller than the aperture of the smaller end of the tapered section 1110.

[0051] like Figure 4 and Figure 5 In some embodiments, a gap 2130 is formed between every two adjacent connecting segments 2110. Wherein, along the circumference of the connecting portion 210, the sum of the arc lengths of all gaps 2130 is L1, and the sum of the arc lengths of all connecting segments 2110 is L2, satisfying: 0.25≤L1 / L2≤1.

[0052] It is understandable that, based on the spacing of each connecting segment 2110, a gap 2130 will inevitably be formed between every two adjacent connecting segments 2110. When the connecting segment 2110 is deformed by the injection hole 110 towards the axis of the connecting part 210, the width of the gap 2130 between two adjacent connecting segments 2110 will decrease on the side away from the main body 220. The sum of the arc lengths of the aforementioned gaps 2130 is the sum of the arc lengths of each gap 2130 before deformation of each connecting segment 2110. If the ratio of L1 to L2 is less than 0.25, the width of each gap 2130 will be small, resulting in less space for deformation of the connecting segment 2110, a lower degree of deformation of the connecting segment 2110, and potentially a poor effect on improving the friction between the connecting segment 2110 and the wall of the injection hole 110. If the ratio of L1 to L2 is greater than 1, in the circumferential direction, the space occupied by the notch 2130 will be greater than the space occupied by the connecting segment 2110, resulting in a smaller solid part of the connecting part 210, which makes the strength of the entire connecting part 210 insufficient and affects the connection effect between the connecting part 210 and the tapered segment 1110.

[0053] For example, the value of L1 / L2 can be set to 0.25, 0.5, 0.75, 1, or any value between the two.

[0054] like Figure 3 As shown, in some embodiments, the seal 20 further includes a main body portion 220 and a sealing portion 230. The main body portion 220 is connected to the connecting portion 210. The sealing portion 230 is sleeved on the main body portion 220. The sealing portion 230 is located inside the injection hole 110, and the outer peripheral surface of the sealing portion 230 abuts against the hole wall surface of the injection hole 110.

[0055] Understandably, the main body 220 can be used to connect with the connecting part 210 and to fit the sealing part 230. When the sealing element 20 is disposed in the injection hole 110, the sealing effect is ensured by the abutment of the sealing part 230 against the wall of the injection hole 110. That is, the sealing element 20 is threadedly connected to the tapered section 1110 of the injection hole 110 through the connecting part 210, ensuring the secure fixing of the sealing element 20, and the sealing element 20 has a good sealing effect by abutting against the wall of the injection hole 110 through the sealing part 230.

[0056] It should be noted that the sealing part 230 is annular. The inner diameter of the sealing part 230 can be less than or equal to the outer diameter of the main body 220, so that the sealing part 230 and the main body 220 can fit together fully after the sealing part 230 is fitted onto the main body 220. The outer diameter of the sealing part 230 can be greater than or equal to the diameter of the injection hole 110, so that the outer peripheral surface of the sealing part 230 can abut against the wall surface of the injection hole 110 after the sealing part 230 is placed in the injection hole 110, thereby ensuring a sealing effect. The sealing part 230 can be made of materials such as rubber.

[0057] In some embodiments, the main body 220 and the connecting portion 210 are integrally formed. That is, each connecting segment 2110 is integrally formed on the end face of the main body 220 and is spaced apart circumferentially on the end face of the main body 220. Since the main body 220 and the connecting portion 210 are integrally formed, both the main body 220 and the connecting portion 210 can be made of metal.

[0058] Please continue reading. Figure 3 In some embodiments, the injection hole 110 includes a first hole section 1120 and a second hole section 1130. The wall surface of the first hole section 1120 is provided with an internal thread 120. The second hole section 1130 communicates with the side of the first hole section 1120 near the outside. The diameter of the second hole section 1130 is larger than the diameter of the first hole section 1120. The connecting part 210 is connected to the first hole section 1120, the main body part 220 is disposed in the second hole section 1130, and the outer peripheral surface of the sealing part 230 abuts against the wall surface of the second hole section 1130.

[0059] Understandably, the first hole section 1120 has an internal thread 120 on its wall surface so that it can be used to connect the connecting portion 210 of the seal 20. The second hole section 1130 is located on the side of the first hole section 1120 closer to the outside so that it can accommodate the main body portion 220 and the sealing portion 230 of the seal 20. Since the diameter of the second hole section 1130 is larger than that of the first hole section 1120, the connecting portion 210, which can pass through the first hole section 1120, must also be able to pass through the second hole section 1130. Furthermore, the larger diameter of the second hole section 1130 provides more space for the sealing portion 230 to be disposed within it. The difference in diameter between the second hole section 1130 and the first hole section 1120 is the radial width of the sealing portion 230.

[0060] It should be noted that the first hole segment 1120 is the aforementioned tapered segment 1110. The side of the first hole segment 1120 closest to the outside is the side of the cover plate 10 away from the electrode assembly after the cover plate 10 is installed on the housing of the single cell.

[0061] Please continue reading. Figure 2 and Figure 3 In some embodiments, the seal 20 further includes an end 240. The end 240 is connected to the end of the main body 220 away from the connecting portion 210. The outer diameter of the end 240 may be the same as the outer diameter of the sealing portion 230. The end 240 is also located within the second hole section 1130. Thus, the entire seal 20 is located within the injection hole 110, preventing the seal 20 from protruding beyond the upper surface of the cover plate 10 and affecting the aesthetics of the cover plate 10.

[0062] Please continue reading. Figure 2 In some embodiments, a groove 2410 is provided on the side of the end 240 away from the main body 220. The groove 2410 can be hexagonal, straight, or cross-shaped. Thus, an auxiliary tool can be used to connect to the groove 2410 to facilitate threaded installation of the seal 20.

[0063] In some embodiments, the end 240, the main body 220, and the connecting part 210 are integrally formed.

[0064] Please continue reading. Figure 5 In some embodiments, the length of the connecting portion 210 is L3 and the length of the main body portion 220 is L4, satisfying: 1≤L3 / L4≤4.

[0065] It is understandable that the main body 220 is a solid structure, while the connecting part 210 is a hollow structure. If the ratio between the length of the connecting part 210 and the length of the main body 220 is less than 1, the length of the connecting part 210 is too short, resulting in a narrow threaded connection area between the seal 20 and the injection hole 110, affecting the connection strength between the seal 20 and the injection hole 110. If the ratio between the length of the connecting part 210 and the length of the main body 220 is greater than 4, the length of the connecting part 210 will be too large. Since the connecting part 210 is a hollow structure, the strength of the seal 20 will be insufficient, making it difficult to meet the usage requirements. Furthermore, in this case, the length of the main body 220 is too short, resulting in a smaller thickness of the sealing part 230 fitted onto the main body 220, leading to poor sealing performance.

[0066] For example, the values ​​of L3 / L4 can be set to 1, 2, 3, 4, or any value between the two.

[0067] This application also provides a single battery cell. The single battery cell includes the top cover assembly as described in the foregoing embodiments.

[0068] In this embodiment, by forming a threaded connection between the seal 20 and the injection hole 110, the seal 20 can be prevented from detaching from the injection hole 110 or falling into the cell due to compression of the cell casing, ensuring the long-term sealing performance of the cell. Since the connecting portion 210 of the seal 20 includes at least two circumferentially spaced connecting segments 2110, when the connecting segments 2110 are threadedly connected to the injection hole 110, because the diameter of at least a portion of the injection hole 110 is smaller than the outer diameter of the connecting portion 210, the injection hole 110 will compress and deform each connecting segment 2110 from its outer circumferential surface to its interior. This deformation will exert a force on the hole wall of the injection hole 110, improving the reliability of the connection between the connecting segments 2110 and the injection hole 110. Therefore, it also prevents the seal 20 from detaching from the injection hole 110 due to vibration of the cell, improving the reliability of the connection between the seal 20 and the injection hole 110 of the cover plate 10.

[0069] This application also provides a battery pack. The battery pack includes individual battery cells as described in the foregoing embodiments.

[0070] In this embodiment, by forming a threaded connection between the seal 20 and the injection hole 110, the seal 20 can be prevented from detaching from the injection hole 110 or falling into the cell due to compression of the cell casing, ensuring the long-term sealing performance of the cell. Since the connecting portion 210 of the seal 20 includes at least two circumferentially spaced connecting segments 2110, when the connecting segments 2110 are threadedly connected to the injection hole 110, because the diameter of at least a portion of the injection hole 110 is smaller than the outer diameter of the connecting portion 210, the injection hole 110 will compress and deform each connecting segment 2110 from its outer circumferential surface to its interior. This deformation will exert a force on the hole wall of the injection hole 110, improving the reliability of the connection between the connecting segments 2110 and the injection hole 110. Therefore, it also prevents the seal 20 from detaching from the injection hole 110 due to vibration of the cell, improving the reliability of the connection between the seal 20 and the injection hole 110 of the cover plate 10.

[0071] The embodiments of this utility model have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A top cover assembly, characterized in that, include: The cover plate is provided with an injection hole, and the wall surface of the injection hole is provided with internal threads; A sealing element includes a connecting portion, the connecting portion comprising at least two connecting segments spaced apart circumferentially thereon, each of the connecting segments being provided with an external thread that matches the internal thread; The connecting part is threaded into the injection hole, and the diameter of at least a portion of the injection hole is smaller than the outer diameter of the connecting part.

2. The top cover assembly according to claim 1, characterized in that, Along the first direction, the injection hole has a tapered section with a decreasing inner diameter, the larger end of the tapered section has a diameter of D1, and the outer diameter of the connecting part is D2, satisfying: D1≤D2.

3. The top cover assembly according to claim 2, characterized in that, The tapered section is tapered, and the inclination angle of the generatrix of the tapered section is α, satisfying: 5°≤α≤45°.

4. The top cover assembly according to claim 3, characterized in that, Along the first direction, each of the connecting segments is inclined toward the axis of the connecting part, and the inclination angle is β, satisfying: β < α.

5. The top cover assembly according to claim 1, characterized in that, A gap is formed between each pair of adjacent connecting segments, wherein the sum of the arc lengths of all the gaps along the circumference of the connecting portion is L1, and the sum of the arc lengths of all the connecting segments is L2, satisfying: 0.25≤L1 / L2≤1.

6. The top cover assembly according to any one of claims 1 to 5, characterized in that, The sealing element further includes: The main body is connected to the connecting part; A sealing part is fitted onto the main body, the sealing part is located inside the injection hole, and the outer peripheral surface of the sealing part abuts against the hole wall surface of the injection hole.

7. The top cover assembly according to claim 6, characterized in that, The injection port includes: The first hole section has the internal thread provided on its hole wall surface; The second hole segment is connected to the side of the first hole segment closest to the outside, wherein the diameter of the second hole segment is larger than the diameter of the first hole segment; The connecting part is connected to the first hole segment, the main body part is disposed in the second hole segment, and the outer peripheral surface of the sealing part abuts against the hole wall surface of the second hole segment.

8. The top cover assembly according to claim 6, characterized in that, The length of the connecting part is L3, and the length of the main body part is L4, satisfying: 1≤L3 / L4≤4.

9. A single battery cell, characterized in that, Includes the top cover assembly as described in any one of claims 1 to 8.

10. A battery pack, characterized in that, Including the single-cell battery as described in claim 9.

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