A lithium battery cell protection plate welding device

Abstract

The application relates to the welding technology field of new energy automobile battery protection plates, and discloses a lithium battery cell protection plate welding device, which comprises a bottom plate, a driving assembly arranged in the bottom plate, a battery body for a new energy automobile arranged in the bottom plate, a connecting shaft fixedly connected to the outside of the driving assembly, a connecting disc fixedly connected to the top of the bottom plate, a sliding groove arranged in the connecting disc, a sleeve fixedly connected to the top of the connecting disc, a bending groove arranged in the sleeve, a convex ball fixedly connected to the inside of the sleeve, a sliding frame movably connected to the top of the connecting shaft, a guide shaft fixedly connected to the outside of the sliding frame, and a pulling disc fixedly connected to the top of the connecting shaft. In the application, uniform surface contact of the whole welding area is realized, the contact state during battery welding is guaranteed, the welding point contact resistance is significantly reduced, the welding point vibration fatigue strength is improved, and the welding yield and the long-term reliability of the battery product are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of welding technology for battery protection boards in new energy vehicles, and in particular to a welding device for cell protection boards of lithium batteries. Background Technology

[0002] Welding of the protection board for lithium-ion battery cells in new energy vehicles is a core process in the lithium-ion battery pack manufacturing process, connecting individual cells to the battery management system (BMS). It primarily establishes a reliable electrical connection between the cell tabs or busbars and the voltage sampling terminals, current detection circuits, and power output interfaces of the protection board, serving as a crucial bridge for cell status signal transmission and power transfer. As the "safety steward" of the lithium-ion battery, the protection board is responsible for real-time monitoring of cell voltage, current, and temperature, performing overcharge, over-discharge, overcurrent, and short-circuit protection, as well as cell balancing functions. The welding quality directly determines the signal acquisition accuracy and current conduction efficiency. Automotive-grade applications require welds with extremely low contact resistance and excellent vibration fatigue strength to withstand the complex driving conditions of new energy vehicles. Currently, the industry mainstream uses laser welding and ultrasonic welding technologies. Laser welding is suitable for joining dissimilar metals such as copper and aluminum, with a small heat-affected zone and high welding precision. Ultrasonic welding requires no solder and can achieve molecular-level solid-state bonding, making it particularly suitable for welding thin tabs to nickel sheets on the protection board, effectively avoiding defects such as incomplete welds and false welds. The production process requires full-process quality control through tensile testing, resistance testing, and metallographic analysis to ensure that the welds are stable and reliable throughout the 8-10 year life cycle of the vehicle, and to prevent risks of local overheating, capacity decay, or even thermal runaway caused by excessive contact resistance.

[0003] However, some existing cell protection board welding devices generally suffer from the problem of failing to achieve a comprehensive, uniform, stable, and tight fit between the battery tabs and the welding surfaces of the protection board. Most devices only use a coarse positioning structure with single-sided cylinder clamping or simple baffle positioning, which cannot achieve synchronous and precise positioning of the battery body in the radial and axial directions. This easily leads to obvious initial misalignment of the welding points between the cell tabs and the protection board, resulting in excessively large local gaps in the welding surfaces. At the same time, these devices often use rigid pressure plates to directly apply pressure or simple pressure with a single spring. The pressure is uncontrollable and unevenly distributed, which easily leads to local point contact rather than complete surface contact. This poor fit directly causes a significant decrease in energy transfer efficiency during laser welding or ultrasonic welding, resulting in insufficient weld penetration and too small fusion area, which in turn produces fatal welding defects such as incomplete welds, false welds, and missed welds.

[0004] Therefore, a cell protection board welding device for lithium batteries is proposed to address the above problems. Summary of the Invention

[0005] To overcome the above deficiencies, the present invention provides a welding device for a cell protection board of a lithium battery.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A welding device for a lithium battery cell protection board includes a base plate, a drive assembly inside the base plate, a battery body for new energy vehicles inside the base plate, a connecting shaft fixedly connected to the outside of the drive assembly, a connecting plate fixedly connected to the top of the base plate, a sliding groove inside the connecting plate, a sleeve fixedly connected to the top of the connecting plate, a bending groove inside the sleeve, a convex ball fixedly connected to the inside of the sleeve, a sliding frame movably connected to the top of the connecting shaft, a guide shaft fixedly connected to the outside of the sliding frame, a pull plate fixedly connected to the top of the connecting shaft, a fixed plate fixedly connected to the top of the sliding frame, a connecting plate fixedly connected to one side of the fixed plate, a fixed plate fixedly connected to the bottom of the connecting plate, an elastic component at the bottom of the fixed plate, a fixed component at the bottom of the base plate, and a welding assembly at the top of the base plate. As a further description of the above technical solution: The drive assembly includes a cylinder, the bottom of which is installed inside the base plate, and a connecting rod is fixedly connected to the output end of the cylinder. One side of the connecting rod is fixedly connected to the outside of the connecting shaft. As a further description of the above technical solution: The elastic component includes a guide rod, the outside of which is slidably connected to the inside of the fixed plate, a spring is sleeved on the outside of the guide rod, a pressure plate is fixedly connected to the bottom of the guide rod, and a contact pad is fixedly connected to the bottom of the pressure plate. As a further description of the above technical solution: The fixing assembly includes a support plate, the top of which is fixedly connected to the bottom of a base plate, a base fixedly connected to the bottom of the support plate, a motor mounted on one side of the support plate, a rotating shaft fixedly connected to the output end of the motor, a bidirectional thread on the outside of the rotating shaft, a threaded sleeve connected to the external thread of the rotating shaft, a clamping plate fixedly connected to the outside of the threaded sleeve, a fixing rod fixedly connected to one side of the support plate, an adjusting screw provided inside the base plate, and a positioning plate rotatably connected to one side of the adjusting screw. As a further description of the above technical solution: The welding assembly includes a top plate, the bottom of which is fixedly connected to the top of a base plate. A guide rail is fixedly connected to the bottom of the top plate, and a welding robotic arm is provided at the bottom of the guide rail. As a further description of the above technical solution: The connecting rod is externally slidably connected to the inside of the sleeve, and the connecting shaft is externally slidably connected to the inside of the groove; As a further description of the above technical solution: The outer side of the guide shaft is slidably connected to the inside of the bending groove, and the outer side of the guide shaft is in contact with the outer side of the convex ball; As a further description of the above technical solution: The external part of the sliding frame is movably connected to the inside of the sleeve, and the external part of the pull plate is movably connected to the inside of the sliding frame; As a further description of the above technical solution: One end of the spring is fixedly connected to the bottom of the fixed plate, and the other end of the spring is fixedly connected to the top of the pressure plate; As a further description of the above technical solution: The top of the clamping plate is slidably connected to the bottom of the base plate, and the inside of the clamping plate is slidably connected to the outside of the fixing rod.

[0007] The present invention has the following beneficial effects: 1. In this invention, the innovative design of the drive assembly in conjunction with the bending groove, guide shaft, convex ball, and movable sliding frame transforms the linear motion of the cylinder into a non-interference composite motion of "first rotating 90° to directly above the battery, then descending vertically." Simultaneously, the small vibration generated by the contact between the guide shaft and the convex ball drives the elastic assembly to automatically fine-tune the pressurization position, eliminating local contact gaps and uneven pressure. Through the layered design of the guide rod, compression spring, pressure plate, and silicone rubber contact pad in the elastic assembly, buffer pressure is provided, which not only avoids mechanical damage caused by rigid pressurization, but also adapts to the slight unevenness of the protective plate surface, achieving uniform surface contact throughout the entire area to be welded. This ensures the contact state during battery welding, ultimately significantly reducing the contact resistance of the weld joint, improving the vibration fatigue strength of the weld joint, and effectively improving the welding yield and long-term reliability of the battery product. Attached Figure Description

[0008] Figure 1 This is a three-dimensional schematic diagram of a lithium battery cell protection board welding device proposed in this invention. Figure 2 This is a schematic diagram of the battery body structure of a cell protection board welding device for lithium batteries proposed in this invention. Figure 3 This is a schematic diagram of the base plate structure of a lithium battery cell protection board welding device proposed in this invention; Figure 4 This is a schematic diagram of the sleeve structure of a lithium battery cell protection board welding device proposed in this invention; Figure 5 This is a schematic diagram of the connecting plate structure of a lithium battery cell protection board welding device proposed in this invention; Figure 6 This is a schematic diagram of the fixing plate structure of a lithium battery cell protection board welding device proposed in this invention; Figure 7 for Figure 6 Enlarged view of point A in the middle; Figure 8 This is a schematic diagram of the clamping plate structure of a lithium battery cell protection board welding device proposed in this invention; Legend: 1. Base plate; 2. Battery body; 3. Cylinder; 4. Connecting rod; 5. Connecting shaft; 6. Connecting plate; 7. Slide groove; 8. Sleeve; 9. Bending groove; 10. Convex ball; 11. Sliding frame; 12. Guide shaft; 13. Pulling plate; 14. Fixing plate; 15. Connecting plate; 16. Fixing plate; 17. Guide rod; 18. Spring; 19. Pressure plate; 20. Contact pad; 21. Support plate; 22. Base; 23. Motor; 24. Rotating shaft; 25. Bidirectional thread; 26. Threaded sleeve; 27. Clamping plate; 28. Fixing rod; 29. ​​Adjusting screw; 30. Positioning plate; 31. Top plate; 32. Guide slide rail; 33. Welding robotic arm. Detailed Implementation

[0009] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0010] Reference Figures 1 to 3 This invention provides an embodiment of a lithium battery cell protection board welding device, comprising a base plate 1. The base plate 1 is the core load-bearing base of the entire lithium battery cell protection board welding device, possessing excellent rigidity and vibration resistance, effectively absorbing mechanical vibrations generated during welding and ensuring welding accuracy. A driving assembly is installed inside the base plate 1, including a cylinder 3, which is the power output element of the driving assembly. The bottom of the cylinder 3 is installed inside the base plate 1, and a connecting rod 4 is fixedly connected to the output end of the cylinder 3. The connecting rod 4 is the power transmission rod of the driving assembly and can move linearly inside the sleeve 8. The reciprocating motion also serves as an auxiliary guide to ensure the smoothness of the movement of the connecting shaft 5. One side of the connecting rod 4 is fixedly connected to the outside of the connecting shaft 5. The base plate 1 is equipped with a battery body 2 for new energy vehicles. The battery body 2 is a square lithium iron phosphate or ternary lithium battery cell used in the power system of new energy vehicles. The top of the battery body 2 is integrated with positive aluminum tabs and negative copper tabs. The cell protection board to be welded is pre-placed at a designated position on the top of the battery body 2. The protection board is equipped with voltage sampling terminals, current detection circuits and power output interfaces. Its welding points correspond one-to-one with the positions of the cell tabs. Reference Figures 2 to 4The drive assembly is externally fixedly connected to a connecting shaft 5, which is a vertically arranged transmission main shaft that can transmit the linear power of the cylinder 3 to the pull plate 13 and the sliding frame 11. The top of the base plate 1 is fixedly connected to a connecting plate 6, and the interior of the connecting plate 6 has a sliding groove 7. The exterior of the connecting shaft 5 is slidably connected to the interior of the sliding groove 7. The top of the connecting plate 6 is fixedly connected to a sleeve 8, and the exterior of the connecting rod 4 is slidably connected to the interior of the sleeve 8. The height of the sleeve 8 is designed according to the lifting stroke of the pressurizing mechanism to ensure that the sliding frame 11 will not interfere when it moves inside, and at the same time to provide precise trajectory constraints for the movement of the guide shaft 12. The interior of the sleeve 8 has a bending groove 9. The bending groove 9 is formed in the sleeve. The inner wall of the sleeve 8 has a closed guide groove, and the width of the bending groove 9 matches the diameter of the guide shaft 12. The sleeve 8 is fixedly connected with a convex ball 10. When the guide shaft 12 slides along the descending section of the bending groove 9, it will contact each convex ball 10 in turn. The protrusion of the convex ball 10 will cause the guide shaft 12 to produce a small radial runout and axial vibration, which will drive the sliding frame 11 to produce a slight wobbling, so that the pressure position of the elastic component can be automatically fine-tuned. The top of the connecting shaft 5 is movably connected to the sliding frame 11. The sliding frame 11 has a circular cavity inside for the installation and movement of the pull plate 13. The diameter of the cavity is slightly larger than the diameter of the pull plate 13, allowing the pull plate 13 to rotate relative to the sliding frame 11 in the cavity. Reference Figures 3 to 5 The sliding frame 11 is externally movably connected to the inside of the sleeve 8. A guide shaft 12 is fixedly connected to the outside of the sliding frame 11. The guide shaft 12 is externally slidably connected to the inside of the bending groove 9. The outside of the guide shaft 12 contacts the outside of the convex ball 10. The guide shaft 12 is the core component for realizing the trajectory conversion of the pressurizing mechanism. Its movement trajectory along the bending groove 9 directly determines the movement state of the sliding frame 11. Through the constraint of the bending groove 9, the linear motion of the connecting shaft 5 is converted into a "rotation + lifting" composite motion of the sliding frame 11. Simultaneously, vibration is generated when passing the convex ball 10, achieving automatic fine-tuning of the pressurizing position. A pull plate 13 is fixedly connected to the top of the connecting shaft 5. The pull plate 13 has a disc-shaped structure, which can... The sliding frame 11 moves linearly with the connecting shaft 5, while also allowing the sliding frame 11 to rotate circumferentially relative to the pull plate 13. This allows the sliding frame 11 to complete the rotational action while moving linearly. The pull plate 13 is externally connected to the inside of the sliding frame 11. A fixed plate 14 is fixedly connected to the top of the sliding frame 11. The function of the fixed plate 14 is to stably transmit the movement of the sliding frame 11 to the connecting plate 15 and the subsequent pressurizing mechanism. A connecting plate 15 is fixedly connected to one side of the fixed plate 14, and a fixed plate 16 is fixedly connected to the bottom of the connecting plate 15. The fixed plate 16 is a rectangular horizontal plate structure, which ensures that multiple guide rods 17 can slide in parallel, prevents the pressurizing plate 19 from tilting, and ensures the uniformity of the pressurizing pressure. Reference Figures 5 to 7The bottom of the fixed plate 16 is provided with an elastic component, which includes a guide rod 17. The guide rod 17 is slidably connected to the inside of the fixed plate 16. The function of the guide rod 17 is to provide precise guidance for the lifting and lowering movement of the pressure plate 19, preventing the pressure plate 19 from tilting or shifting during the pressurization process. A spring 18 is sleeved on the outside of the guide rod 17. During the pressurization process, the spring 18 achieves a buffering effect through its own elastic deformation, avoiding damage to the battery cell and protection board caused by rigid pressurization. The bottom of the guide rod 17 is fixedly connected to the pressure plate 19. The pressure plate 19 has a circular flat plate structure. The diameter of the pressure plate 19 is designed according to the size of the protection board, so that the pressure is evenly distributed on the surface to be welded. To prevent excessive local pressure from causing deformation of the protection plate or breakage of the electrode tab, one end of the spring 18 is fixedly connected to the bottom of the fixing plate 16, and the other end of the spring 18 is fixedly connected to the top of the pressure plate 19. The bottom of the pressure plate 19 is fixedly connected to a contact pad 20. The contact pad 20 is a sheet structure made of silicone rubber, which has good insulation, elasticity and wear resistance. Its surface is processed with fine anti-slip texture, which can increase the friction between the pad and the protection plate and prevent the protection plate from shifting during pressurization. At the same time, its elasticity can further buffer the pressurization pressure, protect the battery cell and the protection plate from damage, and can adapt to the slight unevenness of the protection plate surface to ensure a tight fit. Reference Figure 1 , Figure 2 and Figure 8The bottom of the base plate 1 is equipped with a fixing assembly, which includes a support plate 21. The support plate 21 is a vertically arranged rectangular plate structure. There are two support plates 21, symmetrically distributed on both sides of the bottom of the base plate 1, used to support the weight of the entire device and provide mounting bases for components such as the motor 23, rotating shaft 24, and fixing rod 28. The top of the support plate 21 is fixedly connected to the bottom of the base plate 1, and the bottom of the support plate 21 is fixedly connected to a base 22. The bottom of the base 22 is equipped with four adjustable rubber feet to adjust the level of the device and also to provide vibration isolation and noise reduction. A motor 23 is installed on one side of the support plate 21. The motor 23 is the power source for the fixing assembly. The force output element, motor 23, has a rotating shaft 24 fixedly connected to its output end. The rotating shaft 24 transmits the rotational power of motor 23 to threaded sleeves 26, causing clamping plates 27 to move in opposite directions. The rotating shaft 24 has a bidirectional thread 25 on its outer surface, consisting of two threads with opposite directions of rotation. The thread pitch and tooth profile parameters are identical, ensuring that the two threaded sleeves 26 can move in opposite directions at the same speed when the rotating shaft 24 rotates, achieving synchronous clamping and loosening of the two clamping plates 27. The rotating shaft 24 is externally threaded to the threaded sleeves 26, which have internal threads. The internal threads of the threaded sleeves 26 are connected to the rotating shaft 24. The bidirectional thread 25 on the moving shaft 24 is matched, and a clamping plate 27 is fixedly connected to the outside of the threaded sleeve 26. The top of the clamping plate 27 is slidably connected to the bottom of the base plate 1. A 3mm thick rubber pad is pasted on the clamping surface of the clamping plate 27 to increase the friction between it and the battery body 2, preventing the battery body 2 from sliding during clamping and avoiding damage to the outer shell of the battery body 2 caused by rigid clamping. A fixing rod 28 is fixedly connected to one side of the support plate 21. The inside of the clamping plate 27 is slidably connected to the outside of the fixing rod 28. The function of the fixing rod 28 is to provide precise guidance for the movement of the clamping plate 27 and prevent the clamping plate 27 from rotating under the drive of the threaded sleeve 26. The clamping plate 27 can only move in a straight line in the horizontal direction to ensure the stability and reliability of the clamping. The base plate 1 is equipped with an adjusting screw 29, which is threadedly connected to the threaded hole on the side of the base plate 1. One end of the adjusting screw 29 extends to the battery placement area above the base plate 1 and is rotatably connected to the positioning plate 30 through a thrust bearing. The other end is equipped with a handwheel for easy manual rotation and adjustment. The positioning plate 30 is rotatably connected to one side of the adjusting screw 29. The positioning plate 30 has a rectangular plate structure. One side of the positioning plate 30 is rotatably connected to the end of the adjusting screw 29 through a thrust bearing. The other side is a positioning surface, which is used to contact the end face of the battery body 2 to achieve the positioning of the battery body 2. Reference Figure 1 and Figure 2A welding assembly is provided on the top of the base plate 1. The welding assembly includes a top plate 31, the bottom of which is fixedly connected to the top of the base plate 1. The top plate 31 is a rectangular horizontal flat plate structure. The top plate 31 is fixed to the top of the base plate 1 by four columns. The height of the columns is designed according to the working space of the welding robot arm 33 to ensure that the welding robot arm 33 has sufficient range of motion. A guide rail 32 is fixedly connected to the bottom of the top plate 31. The guide rail 32 is an XY dual-axis linear module, using high-precision linear rails. The X-axis rail of the guide rail 32 is fixed to the lower surface of the top plate 31, and the Y-axis rail... The welding robot arm 33 is mounted on the slider of the X-axis slide rail and the Y-axis slide rail. The guide slide rail 32 is driven by the servo motor 23, which can drive the welding robot arm 33 to move in any direction in the XY plane, covering all welding points on the top of the battery body 2. The welding robot arm 33 is set at the bottom of the guide slide rail 32. The welding robot arm 33 is a multi-joint industrial robot arm with a fiber laser welding head installed at the end. The welding robot arm 33 can automatically adjust the position and angle of the welding head according to the preset welding program to complete the laser welding of the battery cell tabs and the protection board at various points.

[0011] Working principle: When the cell protection board welding device of this lithium battery is working, the fixing component is first started. The motor 23 on the support plate 21 drives the rotating shaft 24 to rotate. Through the external bidirectional thread 25, it drives the two threaded sleeves 26 to move in opposite directions along the fixing rod 28, thereby causing the two clamping plates 27 to clamp the battery body 2 on the base plate 1 simultaneously. Then, the adjusting screw 29 is rotated to push the positioning plate 30 to complete the precise positioning of the battery body 2, ensuring that the welding points of the cell tabs and the protection board are aligned. Then, the drive component is started, and the base plate 1... The cylinder 3 pushes the connecting rod 4, causing the connecting shaft 5 to move linearly along the slide groove 7 of the connecting plate 6. The pull plate 13 at the top of the connecting shaft 5 causes the sliding frame 11 to move synchronously inside the sleeve 8. The guide shaft 12 on the outside of the sliding frame 11 slides along the bending groove 9 on the inner wall of the sleeve 8, rotating from the side of the battery body 2 to directly above the battery body 2. At this time, when the guide shaft 12 moves downward, it will produce a small vibration and change its movement trajectory when it contacts the convex ball 10. The sliding frame 11 can shake while producing a vertical downward displacement. The elastic component is finely adjusted, making the pressure fixing process tighter. Then, the elastic component is lowered through the fixing plate 14, connecting plate 15, and fixing plate 16. The guide rod 17 and spring 18 in the elastic component work together to achieve buffer pressure, so that the contact pad 20 at the bottom of the pressure plate 19 presses the cell protection board and the cell tab to be welded with constant and controllable pressure, avoiding damage to the cell due to excessive pressure or defects such as false welding due to insufficient pressure. Finally, the welding component is started. The guide slide rail 32 at the bottom of the top plate 31 moves the welding robot arm 33 to the preset welding position. Laser welding technology is used to complete the reliable electrical connection between the cell tab and the voltage sampling terminal and current detection circuit of the protection board. After welding, the cylinder 3 reverses to drive the pressure mechanism to reset, and the motor 23 reverses to release the clamping plate 27, so that the welded battery body 2 can be taken out. The whole process realizes the precise positioning, constant pressure clamping and automated welding of the battery through a pure mechanical structure, which meets the quality requirements of low contact resistance and high vibration fatigue strength for automotive-grade lithium battery protection board welding.

[0012] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A cell protection plate welding device of a lithium battery, comprising a bottom plate (1), characterized in that: The base plate (1) is internally equipped with a drive assembly, and the base plate (1) is internally equipped with a battery body (2) for new energy vehicles. A connecting shaft (5) is fixedly connected to the outside of the drive assembly. A connecting plate (6) is fixedly connected to the top of the base plate (1). A sliding groove (7) is provided inside the connecting plate (6). A sleeve (8) is fixedly connected to the top of the connecting plate (6). A bending groove (9) is provided inside the sleeve (8). A convex ball (10) is fixedly connected to the inside of the sleeve (8). The top of the connecting shaft (5) is movably connected to... There is a sliding frame (11), and a guide shaft (12) is fixedly connected to the outside of the sliding frame (11). A pull plate (13) is fixedly connected to the top of the connecting shaft (5). A fixed plate (14) is fixedly connected to the top of the sliding frame (11). A connecting plate (15) is fixedly connected to one side of the fixed plate (14). A fixed plate (16) is fixedly connected to the bottom of the connecting plate (15). An elastic component is provided at the bottom of the fixed plate (16). A fixed component is provided at the bottom of the base plate (1). A welding component is provided at the top of the base plate (1).

2. The lithium battery cell protection plate welding device according to claim 1, characterized in that: The drive assembly includes a cylinder (3), the bottom of which is installed inside the base plate (1), and a connecting rod (4) is fixedly connected to the output end of the cylinder (3). One side of the connecting rod (4) is fixedly connected to the outside of the connecting shaft (5).

3. The lithium battery cell protection plate welding device according to claim 1, characterized in that: The elastic component includes a guide rod (17), the outside of which is slidably connected to the inside of the fixed plate (16), a spring (18) is sleeved on the outside of the guide rod (17), a pressure plate (19) is fixedly connected to the bottom of the guide rod (17), and a contact pad (20) is fixedly connected to the bottom of the pressure plate (19).

4. The cell protection board welding device for a lithium battery according to claim 1, characterized in that: The fixing assembly includes a support plate (21), the top of which is fixedly connected to the bottom of the base plate (1), and a base (22) is fixedly connected to the bottom of the support plate (21). A motor (23) is installed on one side of the support plate (21), and a rotating shaft (24) is fixedly connected to the output end of the motor (23). A bidirectional thread (25) is provided on the outside of the rotating shaft (24), and a threaded sleeve (26) is threaded to the outside of the rotating shaft (24). A clamping plate (27) is fixedly connected to the outside of the threaded sleeve (26). A fixing rod (28) is fixedly connected to one side of the support plate (21), and an adjusting screw (29) is provided inside the base plate (1). A positioning plate (30) is rotatably connected to one side of the adjusting screw (29).

5. The cell protection board welding device for a lithium battery according to claim 1, characterized in that: The welding assembly includes a top plate (31), the bottom of which is fixedly connected to the top of the bottom plate (1), and a guide rail (32) is fixedly connected to the bottom of the top plate (31). A welding robot arm (33) is provided at the bottom of the guide rail (32).

6. The cell protection board welding device for a lithium battery according to claim 2, characterized in that: The external part of the connecting rod (4) is slidably connected to the inside of the sleeve (8), and the external part of the connecting shaft (5) is slidably connected to the inside of the groove (7).

7. The cell protection board welding device for a lithium battery according to claim 1, characterized in that: The outside of the guide shaft (12) is slidably connected to the inside of the bending groove (9), and the outside of the guide shaft (12) is in contact with the outside of the convex ball (10).

8. The cell protection board welding device for a lithium battery according to claim 1, characterized in that: The external of the sliding frame (11) is movably connected to the inside of the sleeve (8), and the external of the pull plate (13) is movably connected to the inside of the sliding frame (11).

9. The cell protection board welding device for a lithium battery according to claim 3, characterized in that: One end of the spring (18) is fixedly connected to the bottom of the fixing plate (16), and the other end of the spring (18) is fixedly connected to the top of the pressure plate (19).

10. The cell protection board welding device for a lithium battery according to claim 4, characterized in that: The top of the clamping plate (27) is slidably connected to the bottom of the base plate (1), and the inside of the clamping plate (27) is slidably connected to the outside of the fixing rod (28).

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