Sealing structure for liquid injection hole of power battery
By designing a wavy curved surface structure for the sealing nail, the problems of easy cracking and deformation of the sealing nail in cylindrical power batteries were solved, improving welding stability and production efficiency, and reducing battery scrap rate and cost.
Patent Information
- Application Number
- CN202422865202.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-22
- Publication Date
- 2025-11-14
- Estimated Expiration
- 2034-11-22
AI Technical Summary
Cylindrical power battery sealing nails are prone to cracking and deformation, leading to poor welding and battery leakage, which affects production yield and cost.
Design a sealing nail structure, including a main body, an annular welding part and a stress relief part. The stress relief part is a wavy curved surface, which is used to alleviate thermal expansion and contraction during welding and enhance the resistance to deformation.
It improves the welding stability of the sealing nails, reduces the risk of battery failure, increases production yield, and reduces costs.
Smart Images
Figure CN223552677U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of power batteries, and in particular to a sealing structure for the liquid injection hole of a power battery. Background Technology
[0002] Currently, lithium-ion / sodium-ion cylindrical batteries are gradually becoming the mainstream product in the new energy industry due to their advantages such as high energy density, good capacity consistency, and ability to support high-rate charge and discharge. More and more manufacturers are continuously pursuing the development of new cylindrical power battery processes and improving production yield to reduce costs. Common questions:
[0003] 1. During the welding of sealing nails for cylindrical power batteries, cracks are prone to occur, which can lead to battery failure. This places higher demands on the thermal expansion and contraction capacity of the sealing nails during laser welding.
[0004] 2. As the penetration welding process has been explored, the requirements for the size of the sealing nails (in the reserved welding area) have become increasingly larger. The larger the sealing nails are, the more prone they are to deformation.
[0005] 3. The sealing pin and the liquid injection groove are a clearance fit. If the fit is too tight or too loose, it will lead to poor fit, which will affect the weld material. Once a burst occurs, it will easily lead to battery leakage. This places higher demands on the sealing pin fit and laser welding positioning. Summary of the Invention
[0006] The purpose of this invention is to provide a sealing structure for the electrolyte filling hole of a power battery, so as to solve the problems of easy cracking and deformation of existing sealing nails.
[0007] To achieve the above objectives, this utility model provides a sealing structure for a power battery injection hole, including a sealing pin disposed within the injection hole. The sealing pin is used to seal the upper part of the injection hole. The sealing pin includes a main body disposed in the middle and an annular welded part disposed on the outer side. The annular welded part is used to weld to the inner wall of the injection hole. A stress relief part is also provided between the main body and the annular welded part. The stress relief part has a wavy curved surface structure in the radial direction. One end of the stress relief part is connected to the lower part of the annular welded part, and the other end of the stress relief part is connected to the main body.
[0008] Preferably, the injection hole is located on the bottom shell or top cover of the power battery. The injection hole includes a groove, and the bottom of the groove has a through hole that penetrates the bottom of the groove. The edge of the bottom of the groove also has an annular boss, and the bottom of the annular weld of the sealing nail overlaps the annular boss.
[0009] Preferably, the sealing structure further includes sealing nails, which seal the through hole portion.
[0010] Preferably, the main body has a downwardly recessed positioning groove in the middle.
[0011] Preferably, the stress relief portion includes a crest portion and a trough portion, and the upper end face of the main body portion, the upper end face of the annular weld portion, and the upper end face of the crest portion are all flush.
[0012] Preferably, the distance between the lower end face of the trough portion and the lower end face of the annular weld portion is greater than or equal to 0.1 mm and less than or equal to 0.45 mm.
[0013] Preferably, the distance between the upper outer edge of the annular welded portion and the center of the main body portion is a first radius, and the width of the stress relief portion in the radial direction is greater than or equal to one-third and less than or equal to two-thirds of the first radius.
[0014] Preferably, the annular weld portion has an outer side surface, which includes an annular vertical surface located at the top and an annular inclined surface connected to the annular vertical surface. The annular inclined surface has a flared structure that tapers towards the center of the sealing nail.
[0015] Preferably, the distance between the upper outer edge of the annular welded part and the upper inner edge of the annular welded part is greater than or equal to 0.5 mm and less than or equal to 0.8 mm, and the height of the annular vertical surface is greater than 0 mm and less than or equal to 0.25 mm.
[0016] Preferably, the lower surface of the main body is a plane, and the distance between the lower surface of the main body and the lower bottom surface of the annular welded part is greater than or equal to 0.4 mm and less than or equal to 0.6 mm.
[0017] Compared with the prior art, this utility model effectively improves the thermal expansion and contraction capacity of the sealing nail during welding by setting the sealing nail as the main body, the annular welding part and the stress relief part, and the stress relief part is wavy. It also increases the sealing nail's resistance to deformation, avoids the hidden danger of battery scrapping in the process, improves the production yield and reduces the cost. Attached Figure Description
[0018] Figure 1 This is a structural diagram of the power battery in an embodiment of this utility model.
[0019] Figure 2 This is a structural diagram of the outer shell in an embodiment of the present utility model.
[0020] Figure 3 This is a cross-sectional view of the outer shell in an embodiment of this utility model.
[0021] Figure 4This is a structural diagram of the sealing nail in an embodiment of this utility model.
[0022] Figure 5 This is a cross-sectional view of the sealing nail in an embodiment of this utility model.
[0023] Figure 6 This is a cross-sectional view of the power battery in an embodiment of this utility model. Detailed Implementation
[0024] To explain in detail the technical content, structural features, and effects of this utility model, the following description is provided in conjunction with the embodiments and accompanying drawings.
[0025] like Figures 1 to 6 As shown, this utility model embodiment provides a sealing structure for the injection hole 12 of a power battery 10, including a sealing pin 2 disposed in the injection hole 12. The sealing pin 2 is used to seal the upper part of the injection hole 12. The sealing pin 2 includes a main body 21 disposed in the middle and an annular welded part 22 disposed on the outer side. The annular welded part 22 is used to weld and connect with the inner wall of the injection hole 12. A stress relief part 23 is also provided between the main body 21 and the annular welded part 22. The stress relief part 23 has a wavy curved surface structure in the radial direction. One end of the stress relief part 23 is connected to the lower part of the annular welded part 22, and the other end of the stress relief part 23 is connected to the main body 21. Specifically, the power battery 10 can be a cylindrical power battery 10. The power battery 10 includes a shell 1 and a bare cell 3 disposed in the shell 1. The liquid injection hole 12 is disposed on the bottom shell 11 or top cover of the power battery 10. For example, in this embodiment of the present invention, the liquid injection hole 12 is located on the bottom shell 11 of the power battery 10. The sealing nail 2 is made of aluminum or steel and is formed by one-piece stamping or cold forging. The main body 21 is in the shape of a circular plate. The outer wall of the annular welding part 22 is matched with the inner wall of the liquid injection hole 12 and connected by laser welding. During the welding process between the sealing nail 2 and the liquid injection hole 12, the sealing nail 2 inevitably undergoes thermal expansion and contraction. The wavy curved surface structure of the stress relief part 23 can avoid the problem of cracking of the sealing nail 2 through elastic deformation. Moreover, after welding, the wavy curved surface structure of the sealing nail 2 forms a tension curved surface, which is equivalent to a reinforcing rib on the surface of the sealing nail 2, which can prevent outward bulging or inward concave irregular shape.
[0026] This embodiment of the utility model, by setting the sealing nail 2 as a main body 21, an annular welding part 22 and a stress relief part 23, and the stress relief part 23 being wavy, effectively improves the thermal expansion and contraction capacity of the sealing nail 2 during welding, and increases the deformation resistance of the sealing nail 2, avoids the hidden danger of battery scrapping in the process, improves the production yield and reduces costs.
[0027] In this embodiment of the utility model, such as Figure 2 , Figure 3 as well as Figure 6As shown, the injection hole 12 includes a groove portion 121, and a through hole portion 122 penetrating the bottom of the groove portion 121. An annular boss 123 is also provided at the edge of the groove bottom, and the bottom of the annular weld portion 22 of the sealing nail 2 overlaps with the annular boss 123. Specifically, the groove wall of the groove portion 121 and the outer wall of the sealing nail 2 are in contact with each other and connected by laser seam welding.
[0028] Furthermore, such as Figure 6 As shown, the sealing structure also includes a sealing nail 5, which seals the through hole portion 122. Specifically, the sealing nail 5 passes through the through hole portion 122 and is press-fitted with the through hole portion 122 to further seal the injection hole 12.
[0029] In this embodiment of the utility model, such as Figures 4 to 5 As shown, the main body 21 has a downwardly recessed positioning groove 24 in the middle. Specifically, the positioning groove 24 can assist in laser positioning before the sealing nail 2 is welded to the groove 121, which is a clever design.
[0030] In this embodiment of the utility model, such as Figure 5 As shown, the stress relief section 23 includes a crest section 231 and a trough section 232. The upper end face of the main body section 21, the upper end face of the annular welding section 22, and the upper end face of the crest section 231 are all flush to ensure the flatness of the end of the power battery 10.
[0031] Furthermore, such as Figure 5 As shown, the distance between the lower end face of the trough portion 232 and the lower end face of the annular weld portion 22 is greater than or equal to 0.1 mm and less than or equal to 0.45 mm. The distance between the lower end face of the trough portion 232 and the lower end face of the annular weld portion 22 is the first distance d. The setting of the first distance d can ensure that when the bottom shell 11 and the collector plate 4 form a protrusion after laser penetration welding, an effective clearance can be formed.
[0032] In this embodiment of the present invention, the distance between the upper outer edge of the annular welding part 22 and the center of the main body part 21 is the first radius R, and the width W of the stress relief part 23 in the radial direction is greater than or equal to one-third of the first radius R and less than or equal to two-thirds of the first radius R.
[0033] In this embodiment of the invention, the annular welding portion 22 has an outer surface, which includes an annular vertical surface 221 located at the top and an annular inclined surface 222 connected to the annular vertical surface 221. The annular inclined surface 222 has a flared structure that tapers towards the center of the sealing nail 2. The annular vertical surface 221 increases the amount of solder in the weld, resulting in a better welding effect. In addition, the annular vertical surface 221 and the annular inclined surface 222 improve the fit between the sealing nail 2 and the groove portion 121.
[0034] In this embodiment of the present invention, the distance between the upper outer edge of the annular welded portion 22 and the upper inner edge of the annular welded portion 22 is greater than or equal to 0.5 mm and less than or equal to 0.8 mm, and the height L of the annular vertical surface 221 is greater than 0 mm and less than or equal to 0.25 mm. Specifically, as shown... Figure 5 As shown, the distance between the upper outer edge of the annular welded portion 22 and the upper inner edge of the annular welded portion 22 is the second distance T, and the second distance T is the thickness of the upper part of the annular welded portion 22.
[0035] In this embodiment of the present invention, the lower surface of the main body 21 is a plane, and the distance between the lower surface of the main body 21 and the lower bottom surface of the annular welded part 22 is greater than or equal to 0.4 mm and less than or equal to 0.6 mm. Specifically, as shown below... Figure 5 As shown, the distance between the lower surface of the main body 21 and the lower bottom surface of the annular welded part 22 is the third distance H.
[0036] The assembly method of the sealing nail 2 and the injection hole 12 in this embodiment of the utility model is as follows: First, the power battery 10 is assembled and produced normally, and the bottom 11 and the collector plate 4 are laser-through welded; after liquid injection or formation, the sealing nail 5 is inserted into the through hole 122; then the sealing nail 2 is fitted with the groove 121. Before welding, the positioning groove 24 is used to assist laser positioning. During welding, when thermal expansion and contraction occur, the wavy curved surface structure of the sealing nail 2 undergoes elastic deformation to avoid problems such as cracking of the sealing nail 2. The annular vertical surface 221 can increase the weld material; after welding, the wavy curved surface structure forms a tension curved surface, which is equivalent to the surface reinforcing rib of the sealing nail 2, and can prevent outward bulging or inward concave irregular shape.
[0037] This utility model embodiment provides a positioning groove 24, a stress relief part 23, an annular welding part 22, and an annular vertical surface 221 on the sealing nail 2 of the cylindrical power battery 10. Before welding the sealing nail 2, the positioning groove 24 assists in laser positioning. During welding, when thermal expansion and contraction occur, the wavy curved surface structure elastically deforms, avoiding problems such as cracking of the sealing nail 2. The annular vertical surface 221 can increase the amount of weld material. After welding, the wavy curved surface structure forms a tension curved surface, equivalent to reinforcing ribs on the surface of the sealing nail 2, preventing convex or concave irregularities. Ultimately, this improves the thermal expansion and contraction resistance of the sealing nail 2 during laser welding, increases its resistance to deformation, improves the compatibility between the sealing nail 2 and the injection groove, avoids the risk of battery scrapping during the process, increases production yield, and reduces costs.
[0038] The above-disclosed examples are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent changes made in accordance with the scope of the present utility model application shall still fall within the scope of the present utility model.
Claims
1. A sealing structure for the electrolyte filling hole of a power battery, characterized in that, Includes a sealing pin disposed within the injection hole, the sealing pin being used to seal the upper part of the injection hole, the sealing pin including a main body portion disposed in the middle and an annular weld portion disposed on the outer side, the annular weld portion being used to weld to the inner wall of the injection hole; A stress relief section is also provided between the main body and the annular welding section. The stress relief section has a wavy curved surface structure in the radial direction. One end of the stress relief section is connected to the lower part of the annular welding section, and the other end of the stress relief section is connected to the main body.
2. The sealing structure for the electrolyte injection port of a power battery as described in claim 1, characterized in that, The injection hole is located on the bottom shell or top cover of the power battery. The injection hole includes a groove, and the bottom of the groove has a through hole that penetrates the bottom of the groove. The edge of the bottom of the groove also has an annular boss. The bottom of the annular weld of the sealing nail overlaps the annular boss.
3. The sealing structure for the electrolyte injection hole of a power battery as described in claim 2, characterized in that, The sealing structure also includes sealing nails, which seal the through hole portion.
4. The sealing structure for the electrolyte injection hole of a power battery as described in claim 1, characterized in that, The main body has a downwardly recessed positioning groove in the middle.
5. The sealing structure for the electrolyte injection port of a power battery as described in claim 1, characterized in that, The stress relief section includes a crest section and a trough section, and the upper end face of the main body, the upper end face of the annular welded section, and the upper end face of the crest section are all flush.
6. The sealing structure for the electrolyte injection hole of a power battery as described in claim 5, characterized in that, The distance between the lower end face of the trough and the lower end face of the annular weld is greater than or equal to 0.1 mm and less than or equal to 0.45 mm.
7. The sealing structure for the electrolyte injection port of a power battery as described in claim 1, characterized in that, The distance between the upper outer edge of the annular welded part and the center of the main body is a first radius, and the width of the stress relief part in the radial direction is greater than or equal to one-third of the first radius and less than or equal to two-thirds of the first radius.
8. The sealing structure for the electrolyte injection port of a power battery as described in claim 1, characterized in that, The annular weld portion has an outer side surface, which includes an annular vertical surface located at the top and an annular inclined surface connected to the annular vertical surface. The annular inclined surface has a flared structure that tapers towards the center of the sealing nail.
9. The sealing structure for the electrolyte injection port of a power battery as described in claim 1, characterized in that, The distance between the upper outer edge of the annular welded part and the upper inner edge of the annular welded part is greater than or equal to 0.5 mm and less than or equal to 0.8 mm, and the height of the annular vertical surface is greater than 0 mm and less than or equal to 0.25 mm.
10. The sealing structure for the electrolyte injection port of a power battery as described in claim 1, characterized in that, The lower surface of the main body is a plane, and the distance between the lower surface of the main body and the lower bottom surface of the annular welded part is greater than or equal to 0.4 mm and less than or equal to 0.6 mm.