Battery top cover, battery top cover forming method, power battery and electric vehicle

Abstract

The present application provides a battery top cover, a forming method for a battery top cover, a power battery, and an electric vehicle. The battery top cover includes a cover plate and a liquid injection hole extending through the cover plate. The cover plate includes a first cover body, and the first cover body includes a first surface and a second surface arranged opposite to each other; wherein the first surface is recessed along a side close to the second surface to form a feeding groove surrounding the liquid injection hole. The present application avoids edge and corner collapse during the processing of the liquid injection hole by setting the first surface of the first cover body to be recessed along a side close to the second surface to form a feeding groove surrounding the liquid injection hole. This facilitates the subsequent sealing operation between the sealing assembly and the battery top cover, thereby reducing the probability of defective power batteries after liquid injection, greatly saving production costs, and improving the sealing performance of the liquid injection hole.

Description

Technical Field

[0001] The present application relates to the field of power batteries, and in particular to a battery top cover, a method for forming a battery top cover, a power battery, and an electric vehicle. Background Art

[0002] The power battery is an important component of electric vehicles. In the existing technology, a through hole is generally directly processed on the battery cover. When the battery cover and the battery shell are assembled, the electrolyte is poured into the battery through the through hole on the cover. After the pouring is completed, the injection hole is plugged with a sealing pin, and then the sealing pin and the battery cover are welded together.

[0003] However, during the processing of through holes in existing battery covers, edges and corners may collapse, which is not conducive to the subsequent sealing operation of sealing nails and battery covers, resulting in poor sealing effect of the injection holes and increasing the probability of defective power batteries after injection.

[0004] Therefore, there is an urgent need to provide a battery top cover, a battery top cover forming method, a power battery and an electric vehicle to solve the technical problems in the prior art that the through holes of the battery cover plate are prone to edge collapse, corner collapse, etc. during the processing process, which are not conducive to the subsequent sealing operation of the sealing nails and the battery cover plate, resulting in poor sealing effect of the injection hole and increasing the probability of defective power batteries after injection. Summary of the Invention

[0005] The present application provides a battery top cover, a forming method for a battery top cover, a power battery and an electric vehicle, aiming to solve the technical problems in the prior art in that the through holes of the battery cover plate are prone to edge collapse and corner collapse during the processing, which are not conducive to the subsequent sealing operation of the sealing nails and the battery cover plate, resulting in poor sealing effect of the injection hole and increasing the probability of defective power batteries after injection.

[0006] In a first aspect, the present application provides a battery top cover, the battery top cover comprising a cover plate and a liquid injection hole extending through the cover plate, the cover plate comprising a first cover body, the first cover body comprising a first surface and a second surface disposed opposite to each other;

[0007] The first surface is recessed along a side close to the second surface to form a feeding groove surrounding the injection hole.

[0008] In a possible implementation of the present application, the distance L1 between the side of the feeding groove close to the injection hole and the side wall of the injection hole satisfies: 0 mm <L1<1mm。

[0009] In a possible implementation of the present application, a distance L1 between a side of the feeding groove close to the injection hole and a side wall of the injection hole satisfies: 0.3 mm ≤ L1 < 0.5 mm.

[0010] In a possible implementation of the present application, the depth H1 of the feeding groove satisfies: 0 mm

[0011] In a possible implementation of the present application, the width W1 of the feeding groove satisfies: 0.1 mm ≤ W1 ≤ 14 mm.

[0012] In a possible implementation of the present application, the cover plate further includes a second cover body fixedly connected to the first cover body, the injection hole includes an injection groove provided on the first cover body and a through hole passing through the second cover body and the injection groove, the width of the injection groove is greater than the diameter of the through hole, the center line of the injection groove coincides with the center line of the through hole, and the depth H2 of the injection groove satisfies: 0 mm <H2≤1mm。

[0013] In a possible implementation of the present application, the injection groove is a tapered groove, and the range of the angle a between the side wall of the injection groove and the center line of the injection groove is: 0° <a≤20°。

[0014] In a possible implementation of the present application, the connection between the liquid injection groove and the through hole is rounded.

[0015] In a possible implementation of the present application, the thickness D1 of the first cover body satisfies: 1 mm ≤ D1 ≤ 5 mm, and the thickness D2 of the second cover body satisfies: 0.2 mm ≤ D1 ≤ 1.5 mm.

[0016] In a possible implementation of the present application, the thickness D1 of the first cover body satisfies: 1 mm ≤ D1 ≤ 3 mm, and the thickness D2 of the second cover body satisfies: 0.4 mm ≤ D1 ≤ 0.8 mm.

[0017] In a possible implementation of the present application, the battery top cover further includes an annular groove recessed along the second surface toward the first surface, the annular groove surrounds the liquid injection hole, and a distance L2 between an outer edge of the annular groove and an outer edge of the liquid injection hole satisfies: 0.5 mm ≤ L2 ≤ 2 mm.

[0018] In a second aspect, the present application provides a method for forming a battery top cover, comprising:

[0019] Provide a cover plate, the cover plate comprising a first cover body and a second cover body, the first cover body comprising a first surface and a second surface disposed opposite to each other;

[0020] Punching is performed along a direction from the first surface to the second surface to form a liquid injection hole;

[0021] ​Punching is performed along a direction from the second surface to the first surface to form a feeding groove surrounding the liquid injection hole.

[0022] In a third aspect, the present application also provides a power battery, comprising the battery top cover described in any of the above implementations.

[0023] In a fourth aspect, the present application also provides an electric vehicle comprising the battery top cover described in any of the above implementations.

[0024] The present application forms a feeding groove surrounding the injection hole by setting a depression along the first surface of the first cover body close to the second surface. When the feeding groove is processed to form the feeding groove, a force is generated along the first surface toward the second surface, and the force generated along the second surface toward the first surface during the processing of the injection hole is completely opposite in direction. This can avoid the phenomenon of edge collapse, corner collapse, etc. caused by the force along the second surface toward the first surface during the processing of the injection hole, facilitate the subsequent sealing operation of the sealing component and the battery top cover, and thereby reduce the probability of defective power batteries after injection, greatly save production costs, and improve the sealing performance of the injection hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 A schematic structural diagram of a battery top cover provided in an embodiment of the present application;

[0027] Figure 2 A schematic diagram of the structure of the liquid injection hole provided in an embodiment of the present application;

[0028] Figure 3 A schematic structural diagram of another liquid injection hole provided in an embodiment of the present application;

[0029] Figure 4 A schematic flow chart of a method for forming a battery top cover according to an embodiment of the present application. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0031] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0032] In this application, the word "exemplary" is used to mean "serving as an example, illustration, or illustration." Any embodiment described in this application as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. The following description is given to enable any person skilled in the art to implement and use the present application. In the following description, details are listed for the purpose of explanation. It should be understood that one of ordinary skill in the art can recognize that the present application can be implemented without using these specific details. In other instances, well-known structures and processes are not elaborated in detail to avoid obscuring the description of the present application with unnecessary details. Therefore, the present application is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles and features disclosed in this application.

[0033] The embodiments of the present application provide a battery top cover, a method for forming a battery top cover, a power battery, and an electric vehicle, which are described in detail below.

[0034] Example 1

[0035] like Figure 1-Figure 2 As shown, the battery top cover 10 includes a cover plate 100 and a liquid injection hole 200 passing through the cover plate 100. The cover plate 100 includes a first cover body 110. The first cover body 110 includes a first surface 111 and a second surface 112 that are oppositely arranged.

[0036] The first surface 111 is recessed along one side close to the second surface 112 to form a feeding groove 300 surrounding the liquid injection hole 200 .

[0037] In the embodiment of the present application, by setting the first surface 111 of the first cover body 110 to be recessed along the side close to the second surface 112, a replenishing groove 300 surrounding the liquid injection hole 200 is formed. When the replenishing groove 300 is processed and formed, a force acting from the first surface 111 towards the second surface 112 can be generated, while a force acting from the second surface 112 towards the first surface 111 generated during the process of processing and forming the liquid injection hole. The directions of these two forces are completely opposite, so that it is possible to avoid phenomena such as edge collapse and corner collapse caused by the force acting from the second surface 112 towards the first surface 111 during the processing of the liquid injection hole 200, facilitating the subsequent sealing operation between the sealing component and the battery top cover 10, thereby reducing the occurrence probability of defective products of the power battery after liquid injection, greatly saving the production cost, and improving the sealing performance of the liquid injection hole 200.

[0038] Further, in some embodiments of the present application, as Figure 2 shown, the distance L1 between the side of the replenishing groove 300 close to the liquid injection hole 200 and the side wall of the liquid injection hole 200 satisfies: 0 mm < L1 < 1 mm.

[0039] Through the above settings, on the one hand, it is possible to avoid the vertical projections of the replenishing groove 300 and the liquid injection hole 200 on the second surface 112 from overlapping, resulting in the force generated when forming the replenishing groove 300 overlapping with the liquid injection hole 200, and this force forms a shear force on the liquid injection hole 200, causing deformation or damage to the liquid injection hole 200, further reducing the occurrence probability of defective products of the power battery; on the other hand, it is also possible to avoid that when L1 is too large, the vertical projection distance between the replenishing groove 300 and the liquid injection hole 200 on the second surface 112 is too large, resulting in the force generated when forming the replenishing groove 300 having little influence on the liquid injection hole 200, and further causing the problem that the replenishing effect of the replenishing groove 300 is not obvious.

[0040] Further, the distance L1 between the side of the replenishing groove 300 close to the liquid injection hole 200 and the side wall of the liquid injection hole 200 satisfies: 0.3 mm ≤ L1 < 0.5 mm.

[0041] Preferably, the distance L1 between the side of the replenishing groove 300 close to the liquid injection hole 200 and the side wall of the liquid injection hole 200 is 0.3 mm.

[0042] Further, as Figure 2 shown, the depth H1 of the replenishing groove 300 satisfies: 0 mm < H1 < 1 mm.

[0043] This is because when the depth H1 of the replenishing groove 300 is too large, it will cause the thickness of the cover plate 100 to be too small, resulting in insufficient strength of the battery top cover 10. Therefore, by setting the depth H1 of the replenishing groove 300 to satisfy 0 mm < H1 < 1 mm, while realizing the replenishment of the liquid injection hole 200, the strength of the battery top cover 10 can also be ensured.

[0044] Preferably, the depth H1 of the feeding groove 300 is 0.1 mm.

[0045] Furthermore, the width W1 of the feeding groove 300 satisfies: 0.1 mm ≤ W1 ≤ 14 mm.

[0046] Because the battery top cover 10 is also provided with other structures spaced apart from the liquid injection hole 200, if the width W1 of the feeding groove 300 is too large, the feeding groove 300 will interfere with these other structures. Furthermore, if the width W1 of the feeding groove 300 is set too large, the process flow for forming the feeding groove 300 will be more complex.

[0047] Therefore, through the above arrangement, while filling the injection hole 200, the process complexity caused by the excessive width W1 of the filling groove 300 and the interference with other structures of the battery top cover 10 are avoided, thereby further improving the reliability of the battery top cover 10.

[0048] Furthermore, in some embodiments of the present application, the width W1 of the feeding groove 300 satisfies: 0.1 mm ≤ W1 ≤ 3 mm.

[0049] Preferably, the width W1 of the feeding groove 300 is 0.75 mm.

[0050] Furthermore, in some embodiments of the present application, Figure 2 As shown, the cover plate 100 also includes a second cover body 120 fixedly connected to the first cover body 110, and the injection hole 200 includes a liquid injection groove 210 provided on the first cover body 110 and a through hole 220 passing through the second cover body 120 and the liquid injection groove 210. The width of the liquid injection groove 210 is greater than the diameter of the through hole 220. The center line of the liquid injection groove 210 coincides with the center line of the through hole 220. The depth H2 of the liquid injection groove 210 satisfies: 0 mm <H2≤1mm。

[0051] The provision of the injection groove 210 can provide an accommodation space for the sealing component in the subsequent sealing process between the sealing component and the battery top cover 10 , thereby preventing the sealing component from extending outside the battery top cover 10 and improving the aesthetics of the battery top cover 10 .

[0052] It should be understood that the sum of the depth H2 of the liquid injection groove 210 and the depth H1 of the material replenishing groove 300 is less than the thickness D1 of the first cover 110 .

[0053] It should also be understood that the first cover 110 and the second cover 120 can be integrally formed.

[0054] Furthermore, in some embodiments of the present application, Figure 2As shown, the injection groove 210 is a tapered groove, and the angle a between the side wall of the injection groove 210 and the center line of the injection groove 210 is in the range of: 0° <a<80°。

[0055] It should be understood that the angle a can be 5°, 10°, 15°, 20°, 30°, 45°, 60°, etc.

[0056] Preferably, the angle a between the sidewall of the liquid injection groove 210 and the center line of the liquid injection groove 210 is 15°.

[0057] The above arrangement can, on the one hand, improve the smoothness of inserting the sealing component; on the other hand, when injecting liquid through the injection hole 200, it can avoid the occurrence of injection liquid residue in the injection hole 200, and can prevent the upper end peripheral portion of the sealing component and the sealing portion of the upper end peripheral portion of the injection hole 200 from being tightly sealed, thereby further reducing the probability of defective battery top cover 10 after injection.

[0058] Furthermore, the connection between the injection groove 210 and the through hole 220 is rounded. This arrangement can effectively prevent burrs or edge wear at the connection between the injection groove 210 and the through hole 220, greatly extending the service life of the sealing component, while effectively improving the sealing effect, preventing electrolyte overflow, and ensuring the product quality of the battery top cover 10.

[0059] Furthermore, in some embodiments of the present application, the thickness D1 of the first cover 110 satisfies: 1 mm ≤ D1 ≤ 5 mm, and the thickness D2 of the second cover 120 satisfies: 0.3 mm ≤ D1 ≤ 1.5 mm.

[0060] Furthermore, the thickness D1 of the first cover 110 satisfies: 1 mm ≤ D1 ≤ 3 mm, and the thickness D2 of the second cover 120 satisfies: 0.4 mm ≤ D1 ≤ 0.8 mm.

[0061] Preferably, the thickness D1 of the first cover 110 is 2 mm, and the thickness D2 of the second cover 120 is 0.7 mm.

[0062] The width W2 of the first cover 110 is greater than the width W3 of the second cover 120 .

[0063] It should be understood that, for ease of manufacturing, the symmetry axis of the first cover 110 coincides with the symmetry axis of the second cover 120 .

[0064] Example 2

[0065] like Figure 3As shown, in some embodiments of the present application, the battery top cover 10 further includes an annular groove 400 that is recessed from the second surface 112 towards the first surface 111. The annular groove 400 is provided around the liquid injection hole 200. The width W4 of the annular groove 400 satisfies: 0.2 mm ≤ W4 ≤ 2 mm, and the depth H3 of the annular groove 400 satisfies: 0 mm < H3 < D1. And the distance L2 between the outer edge of the annular groove 400 and the outer edge of the liquid injection hole 200 satisfies: 0.5 mm ≤ L2 ≤ 2 mm.

[0066] Preferably, the width W4 of the annular groove 400 is 0.5 mm, the depth H3 of the annular groove 400 is 0.8 mm, and the distance L2 between the outer edge of the annular groove 400 and the outer edge of the liquid injection hole 200 is 1 mm.

[0067] By adding the annular groove 400 around the liquid injection hole 200, on the one hand, it can largely offset the stress generated during the sealing process between the sealing component and the battery top cover 10, thereby reducing the occurrence of cracks at the sealing location due to excessive stress during the sealing process; on the other hand, the annular groove 400 can also accommodate the electrolyte that overflows due to some reasons, thus avoiding the contamination of the battery top cover 10 by the electrolyte.

[0068] Furthermore, as Figure 1 shown, the battery top cover 10 further includes an explosion-proof valve component 500, a positive electrode post 600, and a negative electrode post 700 provided on the battery top cover 10. In some embodiments of the present application, the positive electrode post 600 and the negative electrode post 700 are located on both sides of the liquid injection hole 200, and the explosion-proof valve component 500 is located on the side of the liquid injection hole 200 close to the negative electrode post 700.

[0069] Second, the embodiments of the present application further provide a forming method for a battery top cover. As Figure 4 shown, the forming method of the battery top cover 10 includes:

[0070] Step S100: Provide a cover plate 100, the cover plate 100 includes a first cover body 110 and a second cover body 120, and the first cover body 110 includes a first surface 111 and a second surface 112 that are oppositely arranged;

[0071] Step S200: Perform stamping in the direction from the first surface 111 to the second surface 112 to form the liquid injection hole 200;

[0072] Step S300: Perform stamping in the direction from the second surface 112 to the first surface 111 to form a feeding groove 300 surrounding the liquid injection hole 200.

[0073] In the embodiment of the present application, a feeding groove 300 surrounding the injection hole 200 is formed by stamping along the direction from the second surface 112 to the first surface 111, thereby compensating for problems such as collapsed edges and collapsed corners that occur in the process of punching along the direction from the first surface 111 to the second surface 112 to form the injection hole 200, facilitating the subsequent sealing operation of the sealing assembly and the battery top cover 10, thereby reducing the probability of defective power batteries after injection, greatly saving production costs, and improving the sealing performance of the injection hole 200.

[0074] The sizes of the first cover 110 , the second cover 120 , the liquid injection hole 200 and the feeding groove 300 are the same as those in the first embodiment and are not described in detail here.

[0075] Furthermore, in some embodiments of the present application, the method for forming the battery top cover 10 further includes, after step S300:

[0076] Step S400 : Punching is performed along a direction from the first surface 111 to the second surface 112 to form an annular groove 400 surrounding the liquid injection hole 200 .

[0077] The size of the annular groove 400 is the same as that of the annular groove 400 in the first embodiment, and will not be described in detail here.

[0078] In a third aspect, an embodiment of the present application further provides a power battery, which includes a battery top cover 10 , and the battery top cover 10 is the battery top cover 10 in any of the above embodiments.

[0079] In a fourth aspect, an embodiment of the present application further provides an electric vehicle, which includes a battery top cover 10 , and the battery top cover 10 is the battery top cover 10 in any of the above embodiments.

[0080] In summary, in the embodiment of the present application, the first surface 111 of the first cover body 110 is recessed along one side close to the second surface 112 to form a feeding groove 300 surrounding the injection hole 200. When the feeding groove 300 is processed to form the feeding groove 300, a force acting along the first surface 111 toward the second surface 112 can be generated, and the force acting along the second surface 112 toward the first surface 111 generated during the processing of the injection hole is completely opposite in direction, so that the phenomenon of collapsed edge and collapsed corner caused by the force acting along the second surface 112 toward the first surface 111 during the processing of the injection hole 200 can be avoided, thereby facilitating the subsequent sealing operation of the sealing component and the battery top cover 10, thereby reducing the risk of leakage after injection. The probability of defective power batteries is reduced, production costs are greatly saved, and the sealing performance of the injection hole 200 is improved; at the same time, by setting the injection hole 200 to include an injection groove 210 and a through hole 220, the injection groove 210 is a tapered hole, which prevents the upper end periphery of the sealing component and the sealing part of the upper end periphery of the injection hole 200 from being tightly sealed, further reducing the probability of defective battery top cover 10 after injection; and, the embodiment of the present application also provides an annular groove 400 to avoid burrs or edge wear of the sealing component at the connection between the injection groove 210 and the through hole 220, greatly extending the service life of the sealing component, while effectively improving the sealing effect, preventing electrolyte overflow, and ensuring the product quality of the battery top cover 10.

[0081] In the above embodiments, the description of each embodiment has its own focus. For parts not described in detail in a particular embodiment, please refer to the detailed description of other embodiments above and will not be repeated here. In specific implementations, the above units or structures can be implemented as independent entities or in any combination as the same entity or multiple entities, and will not be repeated here.

[0082] The above is a detailed introduction to a battery top cover, a forming method of a battery top cover, a power battery and an electric vehicle provided in the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the structure and core ideas of the present application. At the same time, for those skilled in the art, based on the ideas of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for forming a battery top cover, characterized in that: include: Provide a cover plate, the cover plate comprising a first cover body and a second cover body, the first cover body comprising a first surface and a second surface disposed opposite to each other; Punching is performed in a direction from the first surface to the second surface to form a liquid injection hole, wherein a force acting along the second surface 112 toward the first surface 111 is generated during the punching process to form the liquid injection hole; Stamping is performed in a direction from the second surface to the first surface to form a feeding groove surrounding the injection hole, wherein a distance L1 between a side of the feeding groove close to the injection hole and a side wall of the injection hole satisfies: 0.3mm≤L1<1mm, and a force is generated along the first surface 111 toward the second surface 112 during the process of punching the feeding groove. The force generated along the first surface 111 toward the second surface 112 during the process of punching the feeding groove is in an opposite direction to the force generated along the second surface 112 toward the first surface 111 during the process of punching the injection hole.

2. A battery top cover prepared based on the battery top cover forming method according to claim 1, characterized in that: The battery top cover includes a cover plate and a liquid injection hole passing through the cover plate, the cover plate includes a first cover body, and the first cover body includes a first surface and a second surface arranged opposite to each other; The first surface is recessed along a side close to the second surface to form a feeding groove surrounding the injection hole.

3. The battery top cover according to claim 2, characterized in that: A distance L1 between a side of the feeding groove close to the liquid injection hole and a side wall of the liquid injection hole satisfies: 0.3 mm ≤ L1 < 0.5 mm.

4. The battery top cover according to claim 2, characterized in that: The depth H1 of the feeding groove satisfies: 0mm <H1<1mm。 5. The battery top cover according to claim 2, characterized in that: The width W1 of the feeding groove satisfies: 0.1 mm ≤ W1 ≤ 14 mm.

6. The battery top cover according to claim 2, characterized in that: The cover plate also includes a second cover body fixedly connected to the first cover body, the injection hole includes an injection groove provided on the first cover body and a through hole passing through the second cover body and the injection groove, the width of the injection groove is greater than the diameter of the through hole, the center line of the injection groove coincides with the center line of the through hole, and the depth H2 of the injection groove satisfies: 0 mm <H2≤1mm。 7. The battery top cover according to claim 6, characterized in that: The injection groove is a tapered groove, and the angle a between the side wall of the injection groove and the center line of the injection groove is in the range of: 0° <a<80°。 8. The battery top cover according to claim 7, characterized in that: The connection between the liquid injection groove and the through hole is rounded.

9. The battery top cover according to claim 6, characterized in that: The thickness D1 of the first cover satisfies: 1 mm ≤ D1 ≤ 5 mm, and the thickness D2 of the second cover satisfies: 0.2 mm ≤ D1 ≤ 1.5 mm.

10. The battery top cover according to claim 9, characterized in that: The thickness D1 of the first cover satisfies: 1 mm ≤ D1 ≤ 3 mm, and the thickness D2 of the second cover satisfies: 0.4 mm ≤ D1 ≤ 0.8 mm.

11. The battery top cover according to claim 2, characterized in that: The battery top cover further includes an annular groove recessed along the second surface toward the first surface, the annular groove surrounding the liquid injection hole, and a distance L2 between an outer edge of the annular groove and an outer edge of the liquid injection hole satisfies: 0.5 mm ≤ L2 ≤ 2 mm.

12. A power battery, characterized in that: Comprising a battery top cover as described in any one of claims 2-11.

13. An electric vehicle, characterized in that: Comprising a battery top cover as described in any one of claims 2-11.

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