CN-122000636-A - Novel nickel sheet structure and method for welding battery core and PCM of lithium battery

Abstract

The invention aims to provide a novel nickel sheet structure and a method for welding a lithium battery cell and a PCM. The device comprises a nickel sheet body (1), wherein a bending part (2) is arranged in the middle of the nickel sheet body (1), the bending part (2) forms a preset bending angle, the nickel sheet body (1) is divided into an SMT (surface mount technology) patch surface (3) and a laser welding surface (4) which are staggered mutually through the bending part (2), the SMT patch surface (3) is used for carrying out SMT patch connection with a bonding pad of a PCM (5), the laser welding surface (4) is used for carrying out laser welding with a tab (7) of a lithium battery cell (6), and the preset bending angle is an angle enabling the PCM and the cell to form a convex buffer structure after being put into a shell. The invention is applied to the technical field of battery welding.

Inventors

• ZHANG JING
• LU KAIYI
• ZENG XIN
• TAN SHENGZHU
• LUO LIXIN

Assignees

• 珠海市嘉德电能科技股份有限公司

Dates

Publication Date

20260508

Application Date

20260410

Claims (8)

1. 1. Novel nickel piece structure for lithium cell and PCM welding, a serial communication port, including nickel piece body (1), the middle part of nickel piece body (1) is equipped with kink (2), kink (2) form and predetermine the angle of buckling, nickel piece body (1) pass through kink (2) divide to establish SMT patch face (3) and laser welding face (4) of staggering each other, SMT patch face (3) are used for carrying out SMT patch connection with the pad of PCM (5), laser welding face (4) are used for carrying out laser welding with tab (7) of lithium cell (6), predetermine the angle of buckling for can forming protruding buffer structure after making PCM and electric core income shell.
2. 2. The novel nickel sheet structure according to claim 1, wherein the bottom of the nickel sheet body (1) is provided with supporting feet (8).
3. 3. The novel nickel sheet structure according to claim 2, wherein two supporting legs (8) are arranged, the two supporting legs (8) are symmetrically distributed on two sides of the bottom of the nickel sheet body (1), and the supporting legs (8) are highly matched with the supporting requirement of the nickel sheet body during SMT (surface mount technology) to prevent the nickel sheet body (1) from toppling over during SMT.
4. 4. The novel nickel sheet structure according to claim 1, wherein the surface of the laser welding face (4) is provided with an oxidation-resistant coating.
5. 5. A method for welding a lithium battery cell and a PCM using the novel nickel sheet structure according to any one of claims 1 to 4, comprising the steps of: S1, an SMT patch is coated with solder paste on an SMT patch surface (3), soldering tin is prevented from creeping to a laser welding surface (4), an adaptive bonding pad is designed on a PCM (5), and the SMT patch surface (3) and the bonding pad on the PCM are subjected to patch welding operation; S2, laser welding, namely clamping the nickel sheet body (1) by using a welding clamp, attaching the laser welding surface (4) to the lug of the lithium battery cell, ensuring that the laser welding surface (4) and the lug (7) are positioned on the same horizontal plane, and starting the laser welding equipment for welding; S3, detecting welding spots, after welding, maintaining the clamping state of the nickel sheet body (1) and the tab (7) in a welding clamp, transferring the welding clamp to a welding spot detection procedure, detecting the front and the back of a welding position through a visual detection device, and judging whether the defects of cold welding and perforation exist; S4, assembling the shell, if welding spots are detected to be qualified, integrally assembling the PCM welded with the nickel sheet body and the lithium battery cell into the shell, and forming a convex buffer structure at the bending part of the nickel sheet body and the welding part formed after the nickel sheet body and the electrode lugs are welded together after the nickel sheet body and the electrode lugs are assembled into the shell.
6. 6. The method for welding a lithium battery cell to a PCM according to claim 5, wherein in step S1, the area of the bonding pad on the PCM is identical to the area of the SMT surface of the nickel sheet body, and the distance between the edge of the bonding pad on the PCM and the edge of the laser welding surface of the nickel sheet body is not less than 1mm, so as to prevent soldering tin from creeping.
7. 7. The method for welding a lithium battery cell and a PCM according to claim 5, wherein in step S3, the visual inspection device includes at least two CCD cameras respectively corresponding to the front and the back of the welded portion, the photographing area of the CCD cameras covers the entire welding point, and the quality of the welding point is judged by an image comparison algorithm.
8. 8. The method for welding a lithium battery cell and a PCM according to claim 5, wherein in step S4, the height of the bump buffer structure formed by the bent portion of the nickel sheet body is 0.5-2 mm.

Description

Novel nickel sheet structure and method for welding battery core and PCM of lithium battery Technical Field The invention relates to the technical field of battery welding, in particular to a novel nickel plate structure for welding a lithium battery cell and a PCM (pulse code modulation) and a method for welding the lithium battery cell and the PCM. Background In the production of lithium batteries, in particular lithium polymer batteries, the connection of the cells to the PCM (battery protection plate) is usually made using nickel plates as intermediate connectors and is fixed by laser welding. Laser welding is widely used in this process because of its high welding efficiency and high weld strength. However, the existing laser welding technology and the matched nickel sheet structure still have obvious defects, and the production requirements of high reliability and low cost of the lithium battery are difficult to meet: Firstly, most of the existing nickel plates are of a planar structure or a simple L-shaped structure, and no effective buffer structure exists after the battery cell and the nickel plates are welded. If the battery cell buffer structure is additionally designed for realizing the buffer function, the cost of parts can be increased, the welding space can be occupied by the buffer structure, the alignment precision of laser welding can be influenced, and the welding quality can be further reduced. Secondly, in the existing welding process, the welding spot detection convenience is poor. After the battery cell tab and the nickel sheet are welded, the tab is covered or shielded by the nickel sheet, and the traditional visual inspection can only observe a single surface of a welded part, so that whether defects such as cold welding and perforation exist on the front side and the back side can not be detected simultaneously, and partial hidden welding defective products flow into subsequent procedures to influence the overall reliability of the battery. Furthermore, the scheme of the L-shaped nickel sheet is partially adopted, and for adapting to the assembly positions of the PCM and the battery cell, a nickel sheet folding procedure is added before welding, so that the procedure not only increases the production steps and the labor hour cost, but also can deform the nickel sheet due to stress in the folding process, and further influences the welding precision. Finally, when the planar nickel sheet is subjected to SMT (surface mounted technology) chip bonding with the PCM, soldering tin is easy to climb to a laser welding surface along the surface of the nickel sheet, so that the welding surface is polluted. The polluted welding surface can cause uneven energy reflection during laser welding, so that a welding spot is formed to be in virtual connection or welded through, the welding reliability is reduced, and the defective rate is increased. Therefore, a novel nickel sheet structure and a matched welding method capable of solving the problems of insufficient buffering, inconvenient detection, high cost and tin climbing are needed to improve the reliability and the production efficiency of welding the lithium battery cell and the PCM. Disclosure of Invention The invention aims to solve the defects of the prior art and provides a novel nickel sheet structure and a method for welding a lithium battery cell and a PCM. The novel nickel sheet structure is used for welding a lithium battery cell and a PCM, the novel nickel sheet structure comprises a nickel sheet body, a bending part is arranged in the middle of the nickel sheet body, the bending part forms a preset bending angle, the nickel sheet body is provided with an SMT (surface mount technology) patch surface and a laser welding surface which are staggered mutually through the bending part, the SMT patch surface is used for carrying out SMT patch connection with a bonding pad of the PCM, the laser welding surface is used for carrying out laser welding with a tab of the lithium battery cell, and the preset bending angle is an angle enabling the PCM and the cell to form a convex buffer structure after being put into a shell. Further, the bottom of the nickel sheet body is provided with supporting feet. Further, the supporting legs are arranged at two sides of the bottom of the nickel sheet body, the two supporting legs are symmetrically distributed at two sides of the bottom of the nickel sheet body, and the supporting legs are highly matched with the supporting requirements of the nickel sheet body during SMT (surface mount technology) paster, so that the nickel sheet body is prevented from toppling over during SMT paster. Further, an antioxidation coating is arranged on the surface of the laser welding surface. A method for welding a lithium battery cell and a PCM by utilizing the novel nickel sheet structure comprises the following steps: S1, an SMT patch is coated with solder paste on the SMT patch surface, soldering tin is prevented from c