Sealing nail, top cover assembly, secondary battery and vehicle

Abstract

The utility model discloses a sealing nail, a top cover assembly, a secondary battery and a vehicle, and relates to the technical field of new energy batteries. The sealing nail comprises a base body, the base body is used for being contained in a liquid injection hole of a battery cell in a limited mode and fixedly welded to a top cover of the battery cell, the base body is of a circular-truncated-cone-shaped structure, a groove is formed in the large face of the circular-truncated-cone-shaped structure, and the small face of the circular-truncated-cone-shaped structure is used for blocking the liquid injection hole. According to the sealing nail, the top cover assembly, the secondary battery and the vehicle, the problem that an existing sealing nail is prone to cracks after welding can be solved, so that the welding yield is improved, the battery cell sealing reliability is improved, meanwhile, the structural design can be optimized, the structural complexity is reduced, the difficulty of the production process is reduced, and the production process cost is saved.

Description

Technical Field

[0001] The utility model relates to the technical field of new energy batteries, and in particular to a sealing nail, a top cover assembly, a secondary battery and a vehicle. Background Art

[0002] In the production and manufacturing process of power batteries, after the battery is filled, the filling hole on the top cover of the battery cell needs to be sealed to prevent the electrolyte from overflowing from the inside of the battery cell shell through the filling hole. In the prior art, sealing is generally performed by using a sealing nail with a nail cap on the surface of the top cover of the battery cell, and the sealing nail is connected to the top cover of the battery cell by welding to achieve sealing.

[0003] The surface of the sealing pin currently used is flat, and there is no stress relief design for this type of sealing pin. The welding process will generate high heat, and problems such as thermal expansion and contraction and uneven stress will occur during cooling, which will easily cause cracks at the welding point and eventually lead to failure of the battery core seal. In addition, this design has high requirements for the dimensional accuracy of the sealing pin, and it is very easy to generate welding slag or explosion points during welding. Utility Model Content

[0004] The purpose of the utility model is to provide a sealing nail, a top cover assembly, a secondary battery and a vehicle, which can solve the problem of cracks easily generated after welding in the existing sealing nails, thereby improving the welding yield and further improving the reliability of the battery cell sealing, and at the same time can optimize the structural design and reduce the complexity of the structure, thereby reducing the difficulty of the production process and saving the production process cost.

[0005] The embodiment of the utility model is achieved as follows:

[0006] In a first aspect of an embodiment of the utility model, a sealing nail is provided, comprising a base, the base is used to limit the position of the base in the injection hole of the battery cell and is welded and fixed to the top cover of the battery cell, the base is a truncated cone structure, the large surface of the truncated cone structure is provided with a groove, and the small surface of the truncated cone structure is used to block the injection hole. The sealing nail can solve the problem of cracks easily generated after welding in the existing sealing nails, thereby improving the welding yield, and then improving the reliability of the battery cell sealing, and at the same time can optimize the structural design, reduce the complexity of the structure, thereby reducing the difficulty of the production process and saving the production process cost.

[0007] As an implementable manner, along the axial direction of the truncated cone structure, the maximum thickness of the base is H1, the depth of the groove is H2, and the following relationship is satisfied: 0.05H1≤H2≤0.8H1.

[0008] As an implementable manner, along the radial direction of the truncated cone structure, the weld width of the welding point between the base and the top cover is L1, the stress release width of the groove is L2, and the following relationship is satisfied: 0.8L1≤L2≤5L1.

[0009] As an implementable manner, along the axial direction of the truncated cone structure, the minimum thickness of the base is H3, along the radial direction of the truncated cone structure, the diameter of the base is R, and the following relationship is satisfied:

[0010] As an practicable manner, a chamfer structure is provided at a connection between the side wall of the groove and the large surface of the base.

[0011] As an implementable manner, a chamfer structure is provided at a connection between the side wall of the groove and the bottom wall of the groove.

[0012] As an practicable manner, the material of the substrate is aluminum or steel.

[0013] The second aspect of the embodiment of the utility model provides a top cover assembly, including the above-mentioned sealing nail. The sealing nail can solve the problem of cracks easily generated after welding of the existing sealing nails, thereby improving the welding yield, and then improving the reliability of the battery core sealing, and at the same time can optimize the structural design, reduce the complexity of the structure, thereby reducing the difficulty of the production process and saving the production process cost.

[0014] The third aspect of the embodiment of the utility model provides a secondary battery, including the above-mentioned top cover assembly. The sealing nail can solve the problem of cracks easily generated after welding of the existing sealing nails, thereby improving the welding yield, and then improving the reliability of the battery core sealing, and at the same time can optimize the structural design, reduce the complexity of the structure, thereby reducing the difficulty of the production process and saving the production process cost.

[0015] The fourth aspect of the embodiment of the utility model provides a vehicle, comprising the above-mentioned secondary battery. The sealing nail can solve the problem of cracks easily generated after welding of the existing sealing nails, thereby improving the welding yield, and then improving the reliability of the battery core sealing, and at the same time can optimize the structural design, reduce the complexity of the structure, thereby reducing the difficulty of the production process and saving the production process cost.

[0016] The beneficial effects of the embodiments of the utility model include:

[0017] The sealing nail includes a substrate, which is used as the physical basis of the structural design of the sealing nail. During the manufacturing process, the substrate is used to limit the position of the injection hole of the battery cell and is welded and fixed to the top cover of the battery cell. In this way, from the level of the physical structure, the sealing nail and the top cover can be welded and fixed through the substrate. In accordance with the shape and structure of the injection hole, the substrate is a truncated cone structure, the large surface of the truncated cone structure is provided with a groove, and the small surface of the truncated cone structure is used to block the injection hole, so that the outer side of the welding point between the sealing nail and the top cover has enough stress release space (i.e., the cavity area where the groove is located), so the probability of crack generation can be reduced, thereby improving the welding yield, and then improving the reliability of the battery cell sealing. Not only that, the groove is provided on the large surface of the truncated cone structure, which can also optimize the structural design, reduce the complexity of the structure, and has the advantages of simple process and material saving. At the same time, it can also reduce the spatial dead corners of the structural design and avoid the generation of sanitary dead corners that are difficult to clean. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 One of the structural schematic diagrams of the top cover assembly provided in the embodiment of the utility model;

[0020] Figure 2 The second structural schematic diagram of the top cover assembly provided by the embodiment of the utility model;

[0021] Figure 3 This is one of the structural schematic diagrams of a sealing nail provided in one embodiment of the utility model;

[0022] Figure 4 A second structural schematic diagram of a sealing nail provided in an embodiment of the utility model;

[0023] Figure 5 A third structural diagram of a sealing nail provided in an embodiment of the utility model;

[0024] Figure 6 This is one of the structural schematic diagrams of a sealing nail provided in another embodiment of the utility model;

[0025] Figure 7 A second structural schematic diagram of a sealing nail provided in another embodiment of the utility model;

[0026] Figure 8The third structural schematic diagram of the sealing nail provided in another embodiment of the utility model.

[0027] Icon: 100-top cover assembly; 10-sealing nail; 11-base; 12-groove; A-large surface; B-small surface; 20-top cover. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0031] In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the utility model product is usually placed when in use, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0032] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0033] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] Please refer to Figures 1 to 8 The embodiment of the present application provides a secondary battery, including a shell and a top cover assembly 100, wherein the shell is a rectangular structure or a cylindrical structure with an opening at the top, and correspondingly, the cross-sectional shape of the top cover assembly 100 matches the cross-sectional shape of the top opening of the shell. During the manufacturing process, the shell and the top cover assembly 100 are welded and fixed to seal the opening at the top of the shell through the top cover assembly 100, thereby forming a square battery or a round battery accordingly.

[0035] Specifically, Figure 1 and Figure 2 As shown, the top cover assembly 100 includes a top cover 20, the cross-sectional shape of which matches the cross-sectional shape of the top opening of the shell. During the manufacturing process, the shell and the top cover 20 are welded and fixed to seal the top opening of the shell through the top cover 20. On this basis, a liquid injection hole (generally circular) is provided on the top cover 20 to inject electrolyte into the shell through the liquid injection hole. In order to prevent the electrolyte in the shell from overflowing from the shell through the liquid injection hole, the top cover assembly 100 also includes a sealing nail 10, which is welded and fixed to the top cover 20 to seal the liquid injection hole on the top cover 20 through the sealing nail 10.

[0036] Specifically, Figures 1 to 8 As shown, the sealing nail 10 includes a base 11, which is used to be limitedly accommodated in the injection hole of the battery cell and welded and fixed to the top cover 20 of the battery cell. The base 11 is a truncated cone structure, and the large surface A of the truncated cone structure is provided with a groove 12, and the small surface B of the truncated cone structure is used to block the injection hole. The sealing nail 10 can solve the problem of cracks easily generated after welding in the existing sealing nails 10, thereby improving the welding yield, and then improving the reliability of the battery cell sealing, and at the same time can optimize the structural design, reduce the complexity of the structure, thereby reducing the difficulty of the production process and saving the production process cost.

[0037] It should be noted that if Figure 1 and Figure 2As shown, the sealing nail 10 includes a base 11, which serves as the physical basis for the structural design of the sealing nail 10. During the production process, the base 11 is limitedly accommodated in the injection hole, and the base 11 and the top cover 20 are fixed by welding (such as laser welding). In this way, from the level of the physical structure, the sealing nail 10 and the top cover 20 can be welded and fixed through the base 11.

[0038] In accordance with the shape and structure of the injection hole, the base 11 is in a truncated cone shape. The large surface A of the truncated cone is provided with a groove 12. The small surface B of the truncated cone is used to seal the injection hole, so that the cavity area where the groove 12 is located is used as a stress release space, thereby solving the problem of the existing sealing nail 10 being prone to cracks after welding due to its flat surface and lack of stress release design in structure.

[0039] The working principle of avoiding welding cracks by providing the groove 12 on the large surface A of the truncated cone structure is as follows: welding cracks are caused by the joint action of welding stress and other brittle factors, which destroy the bonding force of metal atoms in the local area of ​​the welded joint and form a new interface gap. When the welding material has been fixed, the brittle factors are often solidified. Therefore, the probability of cracks can only be reduced by changing the structure of the sealing nail 10 to provide sufficient stress release space.

[0040] Compared with the sealing nail 10 with a flat surface in the prior art, the probability of cracks is higher because of the lack of stress release space in the structure. The sealing nail 10 provided in the present application has a groove 12 set on the large surface A of the truncated cone structure, so that there is enough stress release space (i.e., the cavity area where the groove 12 is located) on the outside of the welding point between the sealing nail 10 and the top cover 20, so the probability of cracks can be reduced, thereby improving the welding yield and further improving the reliability of the battery cell sealing. In addition, the groove 12 is set on the large surface A of the truncated cone structure, which can also optimize the structural design and reduce the complexity of the structure. It has the advantages of simple process, saving materials, and reducing the spatial dead corners of the structural design and avoiding the generation of sanitary dead corners that are difficult to clean.

[0041] Regarding the actual shape of the groove 12, for example, in this embodiment, the shape of the groove 12 is circular to match the shape of the base 11. Of course, in other embodiments, the shape of the groove 12 can also be elliptical, angular, diamond, etc. Those skilled in the art should be able to make reasonable selections and designs according to actual conditions, and no specific restrictions are made here. In the production process, the large surface A of the base 11 can be processed by cutting, CNC machining, stamping, cold heading, etc., so as to obtain a sealing nail 10 with a groove 12 provided at the large surface A of the base 11.

[0042] As an implementable manner, along the axial direction of the truncated cone structure, the maximum thickness of the base 11 is H1, the depth of the groove 12 is H2, and the following relationship is satisfied: 0.05H1≤H2≤0.8H1. For example, the actual value of H2 can be 0.05H1, 0.1H1, 0.3H1, 0.7H1 or 0.8H1, etc. Those skilled in the art should be able to make reasonable selections and designs according to actual conditions, and no specific restrictions are made here.

[0043] It should be noted that if Figure 1 As shown, the maximum thickness of the above-mentioned substrate 11 refers to the vertical distance between the large surface A of the substrate 11 and the small surface B of the substrate 11, and the depth of the above-mentioned groove 12 refers to the vertical distance between the large surface A of the substrate 11 and the bottom wall of the groove 12. The maximum thickness of the above-mentioned substrate 11 and the depth of the groove 12 satisfy the following relationship: 0.05H1≤H2≤0.8H1, so as to ensure that there is enough stress release space on the outside of the welding point between the sealing pin 10 and the top cover 20 (that is, the cavity area where the groove 12 is located), thereby ensuring the stress release effect.

[0044] As an implementable manner, along the radial direction of the truncated cone structure, the weld width of the base 11 and the top cover 20 is L1, the stress release width of the groove 12 is L2, and the following relationship is satisfied: 0.8L1≤L2≤5L1. For example, the actual value of L2 can be 0.8L1, 0.9L1, 2L1, 4L1 or 5L1, etc. Those skilled in the art should be able to make reasonable selections and designs according to actual conditions, and no specific restrictions are made here.

[0045] It should be noted that if Figure 2 As shown, the molten width at the welding point between the above-mentioned base body 11 and the top cover 20 refers to the width after the connection between the base body 11 and the top cover 20 (i.e., the welding point) along the large surface A of the base body 11 is heated and melted, and the stress release width of the above-mentioned groove 12 refers to the vertical distance between the center of the welding point between the base body 11 and the top cover 20 and the side wall of the groove 12. The molten width at the welding point between the above-mentioned base body 11 and the top cover 20 and the stress release width of the groove 12 satisfy the following relationship: 0.8L1≤L2≤5L1, so as to ensure that the stress release space is located at a certain distance outside the welding point between the sealing pin 10 and the top cover 20, thereby ensuring the stress release effect.

[0046] As an implementable manner, along the axial direction of the truncated cone structure, the minimum thickness of the base 11 is H3, and along the radial direction of the truncated cone structure, the diameter of the base 11 is R, and the following relationship is satisfied: For example, The actual value of can be 0.015, 0.02, 0.1, 1 or 5, etc. Those skilled in the art should be able to make reasonable selection and design according to the actual situation, and no specific limitation is made here.

[0047] It should be noted that if Figure 1 As shown, the minimum thickness of the above-mentioned base 11 refers to the vertical distance between the bottom wall of the groove 12 and the small face B of the base 11. If a depression is provided on the small face B of the base 11, then at this time, the minimum thickness of the above-mentioned base 11 refers to the vertical distance between the bottom wall of the groove 12 and the bottom wall of the depression on the small face B of the base 11. The diameter of the above-mentioned base 11 refers to the distance between the outer edges of the base 11 on the opposite sides of the large face A of the base 11 (the connecting line needs to pass through the center of the large face A of the base 11). The minimum thickness of the above-mentioned base 11 and the diameter of the base 11 satisfy the following relationship: The strength of the sealing nail 10 is improved to avoid the problem that the sealing nail 10 has poor strength when the minimum thickness of the base 11 is too small and the diameter of the base 11 is too large, which leads to the sealing failure of the sealing nail 10 on the top cover 20.

[0048] like Figure 2 As shown, as an practicable manner, a chamfered structure is provided at the connection between the side wall of the groove 12 and the large surface A of the base 11. Figure 2 As shown, as an implementable method, a chamfer structure is provided at the connection between the side wall of the groove 12 and the bottom wall of the groove 12. The chamfer structure can reduce stress concentration at this position and reduce the spatial dead angle of the structural design, avoiding the generation of sanitary dead angles that are difficult to clean.

[0049] As an implementable manner, the material of the base 11 is aluminum or steel, which can not only meet the strength requirements of the sealing nail 10 itself, but also reduce the production cost.

[0050] The embodiment of the present application further provides a vehicle, comprising the above-mentioned secondary battery. Since the structure and beneficial effects of the secondary battery have been described in detail in the above-mentioned embodiment, they will not be described in detail here.

[0051] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

[0052] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present utility model will not further describe various possible combinations.

Claims

1. A sealing nail, characterized in that: It includes a base, which is used to limit the position of the base in the injection hole of the battery cell and is welded and fixed to the top cover of the battery cell. The base is a truncated cone structure, the large surface of the truncated cone structure is provided with a groove, and the small surface of the truncated cone structure is used to block the injection hole.

2. The sealing nail according to claim 1, characterized in that: Along the axial direction of the truncated cone structure, the maximum thickness of the base is H1, the depth of the groove is H2, and the following relationship is satisfied: 0.05H1≤H2≤0.8H1.

3. The sealing nail according to claim 1, characterized in that: Along the radial direction of the truncated cone structure, the weld width of the welding point between the base and the top cover is L1, the stress release width of the groove is L2, and the following relationship is satisfied: 0.8L1≤L2≤5L1.

4. The sealing nail according to claim 1, characterized in that: Along the axial direction of the truncated cone structure, the minimum thickness of the base is H3, and along the radial direction of the truncated cone structure, the diameter of the base is R, and the following relationship is satisfied:

5. The sealing nail according to claim 1, characterized in that: A chamfered structure is provided at the connection between the side wall of the groove and the large surface of the base.

6. The sealing nail according to claim 1, characterized in that: A chamfered structure is provided at a connection between the side wall of the groove and the bottom wall of the groove.

7. The sealing nail according to claim 1, characterized in that: The material of the substrate is aluminum or steel.

8. A top cover assembly, characterized in that: The sealing nail comprises the sealing nail as claimed in any one of claims 1 to 7.

9. A secondary battery, characterized in that: Includes the top cover assembly as described in claim 8.

10. A vehicle, characterized in that: A secondary battery comprising the secondary battery according to claim 9.

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