Terminal post, top cover structure, battery cell, battery module, and battery pack

Abstract

A terminal post (100), a top cover structure, a battery cell, a battery module, and a battery pack. The terminal post (100) comprises a first metal component (1) and a second metal component (2) connected to each other. One of the first metal component (1) and the second metal component (2) is provided with a protruding section (11), and the other is provided with a first recessed section (22). The protruding section (11) is fitted into the first recessed section (22) and connected therewith. The edge at an end of the second metal component (2) extends outwards to form an extension edge, the first metal component (1) is provided with a second recessed section (12), and the extension edge is fitted into the second recessed section (12).

Description

A pole, a top cover structure, a battery cell, a battery module and a battery pack

[0001] This application claims priority to Chinese patent application No. 202321912361.4 filed with the Patent Office of China on July 20, 2023. The entire contents of the above application are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of battery technology, and specifically to a pole, a top cover structure, a battery cell, a battery module and a battery pack. Background Art

[0003] In power batteries, the terminal is the component that connects the inside and outside of the battery. One end of the terminal is connected to the outside of the battery, and the other end is connected to the internal core pack, thus enabling charging and discharging. The negative electrode of the battery is usually made of two materials.

[0004] In the related art, friction welding is usually used to securely connect two metal parts made of different materials. SUMMARY OF THE INVENTION

[0005] First, different metal materials have different linear expansion coefficients, and friction welding can easily induce thermal stress, which is often difficult to eliminate and can cause significant weld deformation. Second, during the welding process, as welding stress and brittleness increase, cracks are more likely to form on the weld surface, especially in the heat-affected zone, which is more prone to cracking and even fracture, reducing the safety of the terminal.

[0006] Therefore, there is an urgent need to provide a pole, a top cover structure, a battery cell, a battery module and a battery pack to solve the above problems.

[0007] The present application provides a pole, which can improve the bonding strength between the first metal part and the second metal part, reduce the risk of breakage, and improve the reliability of the pole.

[0008] In the first aspect, the present application provides a pole, comprising a first metal part and a second metal part connected to each other, wherein one end of one of the first metal part and the second metal part is provided with a protrusion, and one end of the other is provided with a first recess, and the protrusion is embedded in the first recess; the second metal part extends outward from the edge of one end close to the first metal part to form an extension, and the extension is provided on the periphery of the second metal part, and a second recess is provided on the first metal part, and the extension is embedded in the second recess.

[0009] The present application also provides a top cover structure, including the above-mentioned pole, and also including: a cover plate assembly and a pressure block; a mounting hole is formed on the pressure block, and the second metal part passes through the cover plate assembly and cooperates with the mounting hole, and the first metal part and the pressure block are respectively pressed against the two sides of the cover plate assembly; a welding groove is opened on the surface of the pressure block, and the welding groove is connected to the peripheral side of the mounting hole. The second metal part and the pressure block are fixed by welding, and the welding groove is used to accommodate the welding residual.

[0010] In a second aspect, the present application also provides a battery cell, comprising a shell, a core pack and the above-mentioned top cover structure, wherein the core pack is arranged in the shell, and the top cover structure is sealed and connected to the open end of the shell.

[0011] In a third aspect, the present application also provides a battery module comprising the above-mentioned battery cell.

[0012] In a fourth aspect, the present application also provides a battery pack comprising the above-mentioned battery module. Beneficial effects

[0013] The pole provided in the present application includes a first metal part and a second metal part, which are connected by forming a bonding surface through the engagement of a protrusion with a first recessed part and an extension with a second recessed part. The setting of the extension increases the radial length of the bonding surface, thereby improving the bonding strength between the first metal part and the second metal part, reducing the risk of fracture, and improving the reliability of the pole. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG1 is a schematic structural diagram of a pole provided in an embodiment of the present application;

[0015] FIG2 is an axial cross-sectional view of a pole provided in an embodiment of the present application;

[0016] FIG3 is a schematic structural diagram of a top cover structure provided in an embodiment of the present application;

[0017] FIG4 is an exploded view of the top cover structure provided in an embodiment of the present application.

[0018] In the picture:

[0019] 100, pole; 200, cover plate assembly; 300, pressing block; 310, mounting hole; 320, welding groove; 400, connecting piece; 410, stepped hole;

[0020] 1. First metal member; 11. Raised portion; 12. Second recessed portion; 13. First groove;

[0021] 2. Second metal part; 21. Extended edge; 22. First recessed portion; 23. Second groove. Modes for Carrying Out the Invention

[0022] As shown in Figures 1 and 2, this embodiment provides a pole 100, which is applied to the top cover structure and is located at the negative pole of the battery. Specifically, as shown in Figures 3 and 4, the top cover structure includes a cover assembly 200, a pressure block 300, a connecting piece 400 and a pole 100. The pole 100 includes a first metal part 1 and a second metal part 2 connected to each other. A mounting hole 310 is formed on the pressure block 300. The second metal part 2 passes through the cover assembly 200 and cooperates with the mounting hole 310. The first metal part 1 and the pressure block 300 are respectively pressed against both sides of the cover assembly 200. The end of the second metal part 2 facing away from the first metal part 1 is connected to the outside of the battery, and the end of the first metal part 1 facing away from the second metal part 2 is welded to the connecting piece 400. The connecting piece 400 is connected to the internal core pack of the battery, thereby realizing the charging and discharging functions.

[0023] Specifically, as shown in Figures 1 and 2, the pole 100 is made of a composite plate through a cold heading process. Of course, it can also be formed by cold heading of a first metal member 1 and a second metal member 2, which are separately provided. One of the first metal member 1 and the second metal member 2 has a raised portion 11 at the center of one end, and a first recessed portion 22 at the center of one end. The raised portion 11 is embedded in the first recessed portion 22. In this embodiment, the raised portion 11 is provided at one end of the first metal member 1, and the first recessed portion 22 is provided at one end of the second metal member 2. The second metal member 2 extends outward from one end edge of the first metal member 1 to form an extension 21. The extension 21 is provided around the periphery of the second metal member 2. The first metal member 1 also has a second recessed portion 12, which is provided around the raised portion 11 and embedded in the second recessed portion 12. Optionally, one of the first metal member 1 and the second metal member 2 is a copper pole and the other is an aluminum pole. In this embodiment, the first metal component 1 is a copper column, and the second metal component 2 is an aluminum column.

[0024] The pole 100 provided in this embodiment is formed from a copper-aluminum composite plate through a cold heading process. Compared to conventional poles 100 formed by friction welding, the cold heading process eliminates welding and CNC machining processes, improving production efficiency while effectively reducing material waste and better controlling production costs. Specifically, the protrusion 11 engages with the first recess 22, and the edge 21 engages with the second recess 12, so that the first metal member 1 and the second metal member 2 are affixed to each other to form a bonding surface that connects the first metal member 1 and the second metal member 2. The provision of the edge 21 increases the radial length of the bonding surface, thereby improving the bonding strength between the first metal member 1 and the second metal member 2, reducing the risk of fracture, and improving the reliability of the pole 100.

[0025] In this embodiment, referring to Figures 1 and 2 , both the first metal member 1 and the second metal member 2 are cylindrical structures, and the outer diameter of the first metal member 1 is larger than that of the second metal member 2. This allows the second metal member 2 to abut against the lower surface of the cover plate assembly 200 after being inserted through the cover plate assembly 200, thereby forming a retaining force. The raised portion 11 and the second recessed portion 12 are both arranged circumferentially around the first metal member 1. The raised portion 11 is formed by the flow of material from the first metal member 1 during the ramming process. The first recessed portion 22 and the extended edge 21 are both arranged circumferentially around the second metal member 2. The extended edge 21 is formed by the spread of material from the second metal member 2 during the ramming process.

[0026] Among them, after the second metal part 2 passes through the cover assembly 200 and mates with the mounting hole 310, the second metal part 2 and the pressure block 300 are fixed by laser welding. As shown in Figures 3 and 4, a welding groove 320 is opened on the surface of the pressure block 300. The welding groove 320 is connected to the circumference of the mounting hole 310. The second metal part 2 and the pressure block 300 are fixed by welding. The welding groove 320 is used to accommodate the weld residue. Specifically, the upper surface of the pressure block 300 is set higher than the upper surface of the second metal part 2. The welding groove 320 is circular. The mounting hole 310 is opened at the bottom of the welding groove 320 and is coaxial with the mounting hole 310. The radial dimension of the welding groove 320 is larger than the radial dimension of the mounting hole 310, thereby forming a step structure at the top of the pressure block 300. It is understandable that when welding the pressure block 300 and the second metal part 2, welding will be performed at the top of the pressure block 300 along the junction of the pole 100 and the pressure block 300, so that during welding, the aluminum material on the top of the second metal part 2 will be squeezed out to form a weld residue. The welding groove 320 is used to accommodate the weld residue extruded by welding, and prevent the weld residue from protruding from the upper surface of the pressure block 300 and the second metal part 2, thereby ensuring the smoothness and aesthetics of the appearance of the top cover structure. In other embodiments, the shape of the welding groove 320 can also be square, oval or other special shapes, as long as the outer edge size of the welding groove 320 can be larger than the outer edge size of the mounting hole 310, and no specific limitation is made here.

[0027] As shown in Figures 2 and 4, the edge of the first metal member 1 is constructed as a stepped structure, and a stepped hole 410 is formed on the connecting piece 400. The stepped structure is used to cooperate with the stepped hole 410, and the stepped surface of the first metal member 1 abuts the stepped surface of the stepped hole 410. By adopting this arrangement, the positioning effect between the first metal member 1 and the connecting piece 400 can be improved. After assembly, the mutual movement between the first metal member 1 and the connecting piece 400 can be restricted to facilitate the subsequent assembly and welding process. At the same time, the cooperation of the stepped surface can block the gap between the smaller outer diameter portion of the first metal member 1 and the hole wall of the stepped hole 410, preventing the heat generated by welding from being transferred through the gap to the vicinity of the cover assembly 200.

[0028] As shown in FIG2 , the outer wall of the second metal member 2 is tilted relative to its axis, and the wall of the mounting hole 310 has the same tilt direction and tilt angle as the outer wall of the second metal member 2, and the outer wall of the second metal member 2 fits snugly with the wall of the mounting hole 310. Optionally, the angle θ between the outer wall of the second metal member 2 and its axis is greater than 0° and less than or equal to 3°, for example, the angle θ is 1°, 2°, or 3°. In this embodiment, the outer wall of the second metal member 2 is tilted from bottom to top toward its axis. In other embodiments, the outer wall of the second metal member 2 can also be tilted from bottom to top toward a direction away from its axis, and the wall of the mounting hole 310 can be set to the same tilt direction and tilt angle. In other words, the outer wall of the second metal member 2 is a slope, and the wall of the mounting hole 310 is also a slope, so that the first metal member 1 and the mounting hole 310 fit together through the slope. On the one hand, the setting of the bevel prevents the laser from directly burning the lower plastic part of the cover assembly 200 during laser welding. On the other hand, the matching surface of the second metal part 2 and the pressing block 300 can form an interlocking through the bevel, thereby improving the structural strength of the top cover structure.

[0029] Optionally, as shown in FIG2 , the ratio D / d of the minimum diameter D of the second metal part 2 to the maximum diameter d of the first metal part 1 is greater than or equal to 0.5 and less than 1. It should be noted that when the outer wall of the second metal part 2 is a vertical surface, the diameter of the second metal part 2 at every point along the axial direction remains unchanged, and this diameter is the minimum diameter D of the second metal part 2. When the outer wall of the second metal part 2 is an inclined surface, the diameter of the second metal part 2 at every point along the axial direction is different. At this time, the diameter at the thinnest position of the second metal part 2 is the minimum diameter D of the second metal part 2. In this embodiment, the minimum diameter D of the second metal part 2 is the diameter of the topmost part of the second metal part 2. As shown in FIG2 , the first metal part 1 is a stepped structure, so the maximum diameter d of the first metal part 1 is the diameter of the largest part of the first metal part 1. Exemplarily, D / d can be 0.5, 0.6, 0.7, 0.8 or 0.9. By setting D / d within this range, the structural strength of the pole 100 can be ensured, and the outer diameter of the first metal part 1 can be ensured to be greater than the outer diameter of the second metal part 2, so that after the second metal part 2 passes through the cover plate assembly 200, the first metal part 1 can abut against the lower surface of the cover plate assembly 200 to form a limiting effect.

[0030] 2 , a first groove 13 is formed by ramming at one end of the first metal part 1 facing away from the second metal part 2. Specifically, when the first metal part 1 is rammed and formed using a cold heading die, the first groove 13 is formed by ramming at the same time. While the first groove 13 is being formed by ramming, a first protrusion 11 is formed on the other side of the first metal part 1. The first protrusion 11 is then rammed into a first recessed portion 22 on the second metal part 2. In addition, when the first groove 13 is rammed at the bottom of the first metal part 1, a portion of the material can be moved to both sides. Based on the isovolumetric deformation of ramming, the diameter of the first metal part 1 can be made larger to meet the size requirements, and the dimensions around the first groove 13 can be made fuller to ensure the structural strength of the first metal part 1.

[0031] As shown in Figure 2, optionally, the ratio L / R of the length L of the extended edge 21 along its radial direction to the maximum radius R of the second metal part 2 is greater than or equal to 0.1 and less than or equal to 0.5. From this description, it can be seen that since the outer wall of the second metal part 2 is a slope, the radius at the thickest position of the second metal part 2 is the maximum radius R of the second metal part 2. In this embodiment, the maximum radius R of the second metal part 2 is the diameter of the bottom of the second metal part 2. Exemplarily, L / R can be 0.1, 0.2, 0.3, 0.4 or 0.5. By setting L / R within this range, it can be ensured that the size of the extended edge 21 can increase the radial length of the bonding surface without exceeding the radial size of the first metal part 1, thereby improving the bonding strength between the first metal part 1 and the second metal part 2, reducing the risk of fracture, and improving the reliability of the pole 100.

[0032] Optionally, as shown in FIG2 , the ratio h / H of the thickness h of the extended edge 21 to the maximum thickness H of the first metal member 1 is greater than or equal to 0.1 and less than or equal to 0.5. Since the axial dimensions of the first metal member 1 are different, in this embodiment, the maximum thickness of the first metal member 1 is the thickness of the first metal member 1 near the edge. Exemplarily, h / H can be 0.1, 0.2, 0.3, 0.4 or 0.5. By setting h / H within this range, the depth of the extended edge 21 embedded in the first recess 22 can be ensured, thereby improving the bonding strength between the first metal member 1 and the second metal member 2, reducing the risk of fracture, and improving the reliability of the pole 100.

[0033] It should be noted that during the forging process, a series of wavy lines are formed radially on the surface of the end of the first metal part 1 facing away from the second metal part 2. The lines are naturally formed due to the flow of the material during the cold forging process, which can increase the structural strength of the first metal part 1 and thus improve the structural strength of the pole 100.

[0034] As shown in Figure 2, a second groove 23 is formed by embossing the end of the second metal member 2 facing away from the first metal member 1. By embossing the second groove 23 at the top of the second metal member 2, the material originally located in the second groove 23 can be moved to other locations on the second metal member 2. Since the diameter of the second metal member 2 remains unchanged during molding, the height of the second metal member 2 is increased, saving material and reducing costs while still meeting the design size requirements.

[0035] This embodiment also provides a battery cell, including a shell, a core package and a top cover structure, wherein the core package is arranged in the shell, and the top cover structure is sealed to the open end of the shell. The shell is used to support the core package and provide effective restraint and protection for the core package. The shell can be made of a conductive metal material, such as aluminum, aluminum alloy, etc., and the battery top cover can be sealed and connected to the shell by welding. The battery cell provided in this embodiment can improve the safety of the battery cell and reduce the production cost of the core package by adopting the top cover structure provided in this embodiment.

[0036] This embodiment further provides a battery module, including a battery cell. The battery module provided by this embodiment, by using the battery cell provided by this embodiment, can improve the safety of the battery module and reduce the production cost of the battery module.

[0037] This embodiment further provides a battery pack, including a battery module. The battery pack provided by this embodiment, by adopting the battery module disclosed in this embodiment, can improve the safety of the battery pack and reduce the production cost of the battery pack.

Claims

1. A pole, comprising a first metal member (1) and a second metal member (2) connected to each other, wherein one end of the first metal member (1) and the second metal member (2) is provided with a protrusion (11), and one end of the other is provided with a first recess (22), wherein the protrusion (11) is engaged and connected in the first recess (22); The second metal part (2) extends outward from one end edge close to the first metal part (1) to form an extension (21), and the extension (21) is arranged at the periphery of the second metal part (2). The first metal part (1) is provided with a second recessed portion (12), and the extension (21) is embedded in the second recessed portion (12).

2. The pole according to claim 1, wherein: The protruding portion (11) is provided at one end of the first metal member (1), the second recessed portion (12) is provided around the protruding portion (11), and the first recessed portion (22) is provided at one end of the second metal member (2).

3. The pole according to claim 1, wherein: The ratio L / R of the length L of the extended edge (21) along its radial direction to the maximum radius R of the second metal part (2) is greater than or equal to 0.1 and less than or equal to 0.

5.

4. The pole according to claim 1, wherein: The ratio h / H of the thickness h of the extended edge (21) to the maximum thickness H of the first metal part (1) is greater than or equal to 0.1 and less than or equal to 0.

5.

5. The pole according to any one of claims 1 to 4, wherein: One of the first metal piece (1) and the second metal piece (2) is a copper column, and the other is an aluminum column.

6. The pole according to any one of claims 1 to 5, wherein: The ratio D / d of the minimum diameter D of the second metal part (2) to the maximum diameter d of the first metal part (1) is greater than or equal to 0.5 and less than 1.

7. The pole according to any one of claims 1 to 6, wherein: A surface of the first metal member (1) at an end facing away from the second metal member (2) is provided with corrugated patterns.

8. The pole according to any one of claims 1 to 7, wherein: A first groove (13) is provided at one end of the first metal member (1) facing away from the second metal member (2).

9. The pole according to any one of claims 1 to 8, wherein: A second groove (23) is provided at one end of the second metal member (2) facing away from the first metal member (1).

10. The pole according to any one of claims 1 to 9, wherein: The pole is formed by cold heading.

11. A top cover structure, comprising the pole according to any one of claims 1 to 10, further comprising: A cover plate assembly (200); A pressing block (300) having a mounting hole (310) formed thereon, the second metal member (2) passing through the cover plate assembly (200) and then engaging with the mounting hole (310), the first metal member (1) and the pressing block (300) respectively being pressed against two sides of the cover plate assembly (200); A welding groove (320) is provided on the surface of the pressing block (300), and the welding groove (320) is connected to the peripheral side of the mounting hole (310). The second metal part (2) and the pressing block (300) are fixed by welding, and the welding groove (320) is configured to accommodate welding residue.

12. The roof structure according to claim 11, wherein: The outer wall of the second metal component (2) is arranged to be inclined relative to its axis, the hole wall of the mounting hole (310) and the outer wall of the second metal component (2) have the same inclination direction and inclination angle, and the outer wall of the second metal component (2) fits snugly with the hole wall of the mounting hole (310).

13. A battery cell, comprising a shell, a core package and a top cover structure as claimed in claim 11 or 12, wherein the core package is arranged in the shell, and the top cover structure is sealed and connected to the open end of the shell.

14. A battery module comprising the battery cell as claimed in claim 13.

15. A battery pack comprising the battery module according to claim 14.

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