A copper-aluminum composite electrode terminal structure and a processing method thereof

Abstract

The application discloses a copper-aluminum composite electrode terminal structure and a processing method thereof, which comprises a bottom plate and a composite column; a penetrating hole penetrating through the bottom plate is arranged on the bottom plate, and a first step is arranged at the bottom of the bottom plate; the composite column is rolled by copper and aluminum, and the bottom end and the top end of the composite column are made of two different materials, the middle part is a composite interface, the second step and the third step exist on the periphery of the composite column, a groove is arranged at the bottom end of the composite column and is formed by extruding the bottom end to the top end direction, the material at the bottom end is extruded to the two sides to reduce the gap, the stability of the composite column and the bottom plate is improved, and the resistance is reduced. Compared with the traditional electrode terminal, the application has the characteristics of strong structural reliability, simple manufacturing process, low cost and the like, and has obvious advantages in improving the consistency of the electrode terminal manufacturing process and reducing the manufacturing cost.

Description

Technical Field

[0001] This invention relates to the field of energy storage lithium battery technology, and in particular to a copper-aluminum composite electrode terminal structure and its processing method. Background Technology

[0002] In recent years, driven by the concept of "green and sustainable development," the new energy vehicle market has continued to expand rapidly, leading to a surge in the new energy battery market. Currently, new energy batteries generally adopt a square aluminum shell structure, consisting of a shell and a battery cover. The battery cover provides a sealed space for the battery and also serves as the energy transfer medium; its structure directly affects the reliability and manufacturing cost of the battery pack. Based on these issues, it is necessary to design a reliable, simple, and low-cost new energy battery cover to improve the energy density of new energy batteries and reduce manufacturing costs. The electrode terminals on the battery cover, as the sole carrier of energy transfer in lithium-ion batteries, directly affect the safety of battery use due to their structural reliability and internal resistance.

[0003] Currently, positive and negative electrode terminals are mostly formed by aluminum ingot extrusion and machining, which results in low material utilization and poor dimensional consistency. In particular, for copper-aluminum composite electrodes, copper-aluminum friction welding is required, which has an extremely high risk of failure and no cost advantage. Summary of the Invention

[0004] This invention provides a copper-aluminum composite electrode terminal structure and its processing method, which can improve the consistency of the electrode terminal manufacturing process and reduce manufacturing costs.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A copper-aluminum composite electrode terminal structure includes a base plate and a composite column. The base plate has a through hole and a first step at its bottom. The composite column is made of copper and aluminum rolled together, with the bottom and top ends made of different materials and a composite interface in the middle. The composite column has a second step and a third step around its periphery. The bottom end of the composite column has a groove formed by pressing it towards the top end, which reduces gaps by pressing the bottom material to both sides, thereby improving the stability of the bond between the composite column and the base plate and reducing resistance.

[0006] Preferably, the base plate is made of copper or 1060 aluminum alloy. When the base plate is installed inside a lithium-ion battery and welded to the battery tabs, it is made of copper. When the base plate is installed outside a lithium-ion battery and welded to the battery mold busbar, it is made of 1060 aluminum alloy. When the base plate is installed in a sodium-ion battery structure, it is made of 1060 aluminum alloy.

[0007] Preferably, in a lithium-ion battery, when the base plate is made of copper, the bottom of the composite column is made of copper and the top is made of 1060 aluminum alloy; when the base plate is made of 1060 aluminum alloy, the bottom of the composite column is made of 1060 aluminum alloy and the top is made of copper.

[0008] Preferably, in sodium-ion batteries, the bottom and top ends of the composite column are both made of 1060 aluminum alloy.

[0009] Preferably, the thickness of the base plate is 0.8-3.0 mm, and the depth of the first step is 0-1.0 mm.

[0010] Preferably, the thickness of the bottom of the composite column is 0.05-0.5mm thicker than the thickness of the base plate, that is, the composite interface is 0.05-0.5mm higher than the top of the base plate.

[0011] Preferably, the third step and the first step are mutually matched and have the same depth, which is used to avoid weld protrusion when welding the composite column and the base plate after assembly.

[0012] Preferably, the groove has a depth of 0-1.5 mm and a diameter of 0-20 mm.

[0013] The processing method for the above-mentioned copper-aluminum composite electrode terminal structure includes the following steps: S1. First, stamp out the base plate and composite column using the corresponding stamping dies; S2. Then place the composite column and base plate into the assembly fixture, and use the corresponding punch to extrude the groove of the composite column, and adjust the first step and the third step to the same plane; S3. Finally, laser welding is used to weld the bottom of the composite column and the bottom of the base plate together.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Compared with traditional electrode terminals, the present invention has the characteristics of strong structural reliability, simple manufacturing process and low cost, especially in improving the consistency of electrode terminal manufacturing process and reducing manufacturing cost. 2. By using a base plate and composite column splicing method, the base plate and the guide column are independently stamped and formed to achieve the welding of the negative electrode terminal lugs. This avoids the inefficient CNC machining process, significantly improves the material utilization rate of the copper-aluminum composite plate, and significantly reduces the cost of the composite electrode. 3. The base plate can directly replace the new energy battery adapter plate, which can effectively reduce the internal resistance of the battery and improve the safety of battery use while reducing the number of new energy battery components and simplifying the battery assembly process. 4. Copper-aluminum composite electrode terminals are assembled into components through part stamping, riveting, laser welding, and process assembly. By disassembling the components, the complex, costly, and low-yield friction welding technology, as well as the low-efficiency turning process, are abandoned. Attached Figure Description

[0015] Figure 1 This is a three-dimensional structural diagram of an embodiment of the present invention; Figure 2 This is a schematic diagram of the exploded structure according to an embodiment of the present invention; Figure 3 This is a cross-sectional view of the base plate according to an embodiment of the present invention; Figure 4 This is a cross-sectional structural diagram of the copper-aluminum composite column according to an embodiment of the present invention; Figure 5 This is a schematic cross-sectional view of the structure after the base plate and the copper-aluminum composite column are spliced ​​together according to an embodiment of the present invention; Figure 6 This is a cross-sectional view of the structure after the base plate and the copper-aluminum composite column are welded together according to an embodiment of the present invention.

[0016] In the diagram: 1. Base plate, 11. Through hole, 12. First step, 2. Composite column, 21. Top, 211. Second step, 212. Composite interface, 22. Bottom, 221. Third step, 222. Groove. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0018] like Figures 1 to 6 As shown, the embodiment of the present invention includes a base plate 1 and a composite column 2; the base plate 1 is provided with a through hole 11 penetrating through the base plate 1, and the bottom of the base plate 1 is provided with a first step 12. The composite column 2 is made of copper and aluminum rolled together, with its bottom end 22 and top end 21 being two different materials, and a composite interface 212 in the middle. The composite column 2 has a second step 211 and a third step 221 around its periphery. The bottom end of the composite column 2 is provided with a groove 222 formed by pressing towards the top end, which reduces the gap by pressing the material at the bottom end 22 to both sides, thereby improving the stability of the combination between the composite column 2 and the base plate 1 and reducing the resistance. Example

[0019] The base plate 1 is used for welding the battery tabs inside the lithium-ion battery system. It is made of copper and has a thickness of 1.4mm. The depth of the first step 12 is 0.3mm. The bottom 22 of the corresponding composite post 2 is made of copper and the top 21 is made of 1060 aluminum alloy. The bottom 22 of the composite post 2 has a thickness of 1.5mm and the groove 222 has a depth of 0.8mm and a diameter of 8mm. Example

[0020] The base plate 1 is used for welding the external part of the lithium-ion battery to the busbar of the battery mold. It is made of 1060 aluminum alloy with a thickness of 2.0mm. The depth of the first step 12 is 0.5mm. The bottom end 22 of the corresponding composite column 2 is made of 1060 aluminum alloy, and the top end 21 is made of copper. The bottom end 22 of the composite column 2 has a thickness of 2.2mm, and the groove 222 has a depth of 1mm and a diameter of 10mm. Example

[0021] When the base plate 1 is installed in the sodium-ion battery structure, it is made of 1060 aluminum alloy with a thickness of 1.8 mm. The depth of the first step 12 is 0.4 mm. Correspondingly, the bottom end 22 and top end 21 of the composite column 2 are both made of 1060 aluminum alloy. The bottom end 22 of the composite column 2 has a thickness of 2 mm, and the groove 222 has a depth of 1 mm and a diameter of 10 mm. In the sodium-ion battery structure, conductivity can be guaranteed without using copper, thus saving production costs.

[0022] Preferably, the third step 221 and the first step 12 are matched with each other and have the same depth, which is used to avoid weld protrusion when the composite column 2 and the base plate 1 are assembled and welded.

[0023] When processing the copper-aluminum composite electrode terminal structure, the base plate 1 and the composite column 2 are first stamped out using corresponding stamping dies; then the composite column 2 and the base plate 1 are placed into the assembly fixture, and the groove 222 of the composite column 22 is extruded by the corresponding punch, and the first step 12 and the third step 221 are adjusted to the same plane; finally, the bottom end 22 of the composite column 2 and the bottom of the base plate 1 are welded together using laser welding.

[0024] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A copper-aluminum composite electrode terminal structure, characterized in that: The system includes an independently stamped base plate and an independently stamped composite column. The base plate has a through-hole, and the bottom of the base plate has a first step integrally formed. The composite column is made of rolled copper and aluminum sheets, with the bottom and top of the column made of different metals, forming a composite interface. The outer circumference of the composite column has a second and a third step integrally formed. The third step has the same depth as the first step of the base plate and fits snugly together after assembly, preventing weld protrusion during welding. The bottom of the composite column has a recessed groove formed by stamping towards the top. This groove is formed by extruding the base plate and composite column into a fixture using a punch. During extrusion, the metal at the bottom of the composite column is radially expanded towards the inner wall of the through-hole, filling the assembly gap between the outer wall of the composite column and the through-hole of the base plate, improving the stability of the assembly after the composite column and base plate are assembled separately, and reducing the contact resistance at their interface. The composite column passes through the through-hole of the base plate, and the bottom of the composite column is fixed to the bottom surface of the base plate by laser welding.

2. The copper-aluminum composite electrode terminal structure according to claim 1, characterized in that: The base plate is made of copper or 1060 aluminum alloy. When the base plate is installed inside a lithium-ion battery and welded to the battery tabs, it is made of copper. When the base plate is installed outside a lithium-ion battery and welded to the battery mold busbar, it is made of 1060 aluminum alloy. When the base plate is installed in a sodium-ion battery structure, it is made of 1060 aluminum alloy.

3. The copper-aluminum composite electrode terminal structure according to claim 2, characterized in that: In lithium-ion batteries, when the base plate is made of copper, the bottom of the composite column is made of copper and the top is made of 1060 aluminum alloy; when the base plate is made of 1060 aluminum alloy, the bottom of the composite column is made of 1060 aluminum alloy and the top is made of copper.

4. The copper-aluminum composite electrode terminal structure according to claim 2, characterized in that: In sodium-ion batteries, the bottom and top ends of the composite column are both made of 1060 aluminum alloy.

5. The copper-aluminum composite electrode terminal structure according to claim 2, characterized in that: The thickness of the base plate is 0.8-3.0 mm, and the depth of the first step is 0-1.0 mm.

6. The copper-aluminum composite electrode terminal structure according to claim 5, characterized in that: The thickness of the bottom end of the composite column is 0.05-0.5mm thicker than the thickness of the base plate, that is, the composite interface is 0.05-0.5mm higher than the top of the base plate.

7. The copper-aluminum composite electrode terminal structure according to claim 5, characterized in that: The third step is designed to fit together with the first step and have the same depth, which is used to prevent weld protrusions when welding the composite column and the base plate after assembly.

8. The copper-aluminum composite electrode terminal structure according to claim 5, characterized in that: The groove has a depth of 0-1.5 mm and a diameter of 0-20 mm.

9. A copper-aluminum composite electrode terminal structure according to any one of claims 1-8, characterized in that: The processing method for the above-mentioned copper-aluminum composite electrode terminal structure includes the following steps: S1. First, stamp out the base plate and composite column using the corresponding stamping dies; S2. Then place the composite column and base plate into the assembly fixture, and use the corresponding punch to extrude the groove of the composite column, and adjust the first step and the third step to the same plane; S3. Finally, laser welding is used to weld the bottom of the composite column and the bottom of the base plate together.

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