A laser welding device and method for connecting pieces of multi-row large battery modules

Abstract

This invention discloses a laser welding device and method for multi-row large battery module connectors. The welding device includes a motion platform and welding components. The motion platform includes a machine base, within which a laser system control system is installed. The laser system control system controls the laser and the overall laser optical path. A Y-axis module slide is installed on the machine base, and a product positioning plate is installed on the Y-axis module. The welding components include a fixed frame, an X-axis module, a Z-axis module, and a welding module. The welding module includes a substrate, which is fixedly mounted on the slider of the Z-axis module. The substrate has multiple sets of mounting threaded holes and mounts a galvanizing head and a depth camera. The depth camera is adjacent to the galvanizing head and separated from it by a light-blocking plate. A ring-shaped surface light source is located directly below the depth camera for high-contrast imaging of the welding position. The substrate is equipped with a separate welding nozzle. This method enables high-speed, integrated, safe welding of multi-row large battery module connectors with a large range of motion, as well as rapid and flexible changeover.

Description

Technical Field

[0001] This invention belongs to the field of power battery module processing technology. This invention relates to a laser welding device and method for connecting pieces of multi-row large battery modules. Background Technology

[0002] Against the backdrop of energy transition and increased environmental awareness, the market demand for new energy batteries, as a key technology for clean energy storage and conversion, is growing rapidly. Battery modules, by connecting individual battery cells in series or parallel, are further assembled to form large, multi-row battery modules with greater capacity and voltage. The welding quality of the connecting pieces is crucial to their performance and safety. Laser welding, due to its high efficiency, environmental friendliness, and precision, has become the preferred technology for welding connecting pieces in large, multi-row battery modules. Research and development of automated laser welding equipment and related technical methods can support the automation and intelligent development of manufacturing technology for large, multi-row battery modules.

[0003] A search revealed that patents CN211414159U and CN218385660U disclose automatic welding devices for battery connectors, but these are mainly used for connector processing; patent CN114888402A discloses a single battery casing and battery cover encapsulation welding equipment and process method; patent CN107414297A discloses a battery box encapsulation welding production line system and working method based on vision inspection; and patent CN114054951A discloses a welding device for sealing new energy battery packs, but their designs are all aimed at welding single or multiple battery sealing positions, and the welding objects are different; patent CN117655525B discloses a control method and steps for automatic welding of power battery connectors; and patent CN117086480A discloses a laser welding step method for battery modules based on vision guidance, but does not disclose the relevant laser device mechanism. Existing patents reveal that laser welding equipment for connecting pieces of large multi-row battery modules faces challenges such as structural design with a large working space, low efficiency of the welding system, slow equipment changeover, and safety concerns. There are currently no publicly available technologies related to automatic laser welding devices and methods for large multi-row battery modules that can simultaneously solve these problems. Summary of the Invention

[0004] The purpose of this invention is to provide a laser welding device and method for connecting multi-row large battery module pieces, which aims to achieve high-speed, integrated, safe welding and rapid flexible replacement of connecting multi-row large battery module pieces with a large range of motion.

[0005] The technical solution to achieve the purpose of this invention is as follows:

[0006] A laser welding device for connecting pieces of multi-row large battery modules includes a motion platform and welding components.

[0007] The motion platform includes a machine base, and a laser system control system is installed inside the machine base. The laser system control system is used to control the laser and the laser optical path of the whole machine. A Y-axis module slide is installed on the machine base. The Y-axis module slide is parallel to the set world coordinate system Y-axis. A product positioning plate is installed on the Y-axis module.

[0008] The welding assembly includes a fixed frame, an X-axis module, a Z-axis module, and a welding module. The fixed frame is mounted on the machine base and is vertically distributed on both sides of the Y-axis module slide. The X-axis module is mounted on the fixed frame. The Z-axis module is fixedly mounted on the slider of the X-axis module via an extension mechanism. The welding module includes a base plate, which is fixedly mounted on the slider of the Z-axis module. The base plate includes a main body and an extension, which extends downward from the main body by a certain distance. The main body and the extension are provided with multiple sets of mounting threaded holes. The main body is equipped with a galvanometer lens for adjusting the laser emission direction. The main body is also equipped with a depth camera, which is adjacent to the galvanometer lens and separated from it by a light-blocking plate. A ring-shaped surface light source is located directly below the depth camera for high-contrast imaging of the welding position. The extension is equipped with a separate welding nozzle.

[0009] In a preferred embodiment, the detachable welding nozzle includes a cylinder, a telescopic rod, and a nozzle plate. The cylinder is fixedly installed on the extension of the substrate, located directly below the scanning head. The telescopic rod is connected to the piston rod of the cylinder. The nozzle plate is fixedly installed at the end of the telescopic rod, and the telescopic rod controls the nozzle plate to rise and fall according to the Z-axis coordinate fed back by the depth camera.

[0010] In a preferred embodiment, the substrate is fixedly mounted with a dust extraction pipe by multiple sets of saddle clips, and the dust extraction pipe is located behind the scanning head.

[0011] In a preferred embodiment, the extension is fixedly mounted with a nitrogen blowing assembly via a nitrogen assembly clip. The nitrogen blowing assembly is located on one side of the separate welding nozzle and is used to deliver inert gas.

[0012] In a preferred embodiment, an air knife is provided below the diaphragm head for cleaning dust from the welding area before and during welding.

[0013] In a preferred embodiment, the product positioning plate includes multi-level limiting threaded holes, which are evenly distributed on the product positioning plate for fastening and positioning the orientation adjustment limiting block and the clamping elbow assembly. The orientation adjustment limiting block is located at the corner of the product positioning plate and is slidably connected to the product positioning plate for orientation adjustment of the multi-row large battery module in the X-axis and Y-axis directions. The clamping elbow assembly is symmetrically distributed on both sides of the multi-row large battery module along the Y-axis.

[0014] In a preferred embodiment, the clamping elbow assembly includes a positioning plate, adjusting positioning bolts, and a clamping elbow. The positioning plate is located on both sides of the multi-row large battery module and has two through holes. The positioning plate is connected to the product positioning plate by adjusting positioning bolts for coarse positioning of the multi-row large battery module in the X-axis direction. The clamping elbow is located on the positioning plate.

[0015] In the preferred embodiment, the clamping elbow is threadedly fastened to the multi-row large battery module, and the clamping elbow is elastically connected to a pressure rod. The distance between the positioning pressure plate and the multi-row large battery module is adjusted by adjusting the downward pressing angle of the pressure rod, which is used to limit the multi-row large battery module in the X-axis direction.

[0016] In a preferred embodiment, the motion platform is equipped with a cooling system and an electrical motion control system. The cooling system is used to reduce the internal temperature of the laser equipment during the welding process, and the electrical motion control system is used for the logical functions and electrical integration control of various modules of the laser welding device.

[0017] This invention also discloses a laser welding method for connecting pieces of multi-row large battery modules, using the aforementioned laser welding device for connecting pieces of multi-row large battery modules. The welding method includes the following steps:

[0018] S01: Control the X-axis module and the Y-axis module slide of the motion platform to make the depth camera sequentially acquire images of all welding points according to the set position. After the images of all welding points are acquired, control the X-axis module and the Y-axis module slide of the motion platform to return to the set initial position.

[0019] S02: Perform image stitching and image processing on the acquired images, and calculate the absolute coordinates (X) of all welding points of the multi-row large battery modules in the world coordinate system set by the system. n ,Y n Z n (n=1,2...N), where X n Let X be the X-axis coordinate of the nth weld, and Y be the Y-axis coordinate of the weld. n Let Z be the Y-axis coordinate of the nth weld. n The Z-axis coordinate of the nth weld is given, and N is the total number of weld points. The data is then sent to and stored on the host computer control platform.

[0020] S03: The host computer control platform sends the position (X1, Y1, Z1) of the first welding point of the multi-row large battery module connecting piece to the electrical motion control system through human-computer interaction, and sends the laser welding parameters to the laser system control system.

[0021] S04: The electric motion control system servo controls the combined motion of the X-axis module, Y-axis module slide, and Z-axis module to move the scanning head to the first welding point position (X1, Y1, Z1) of the multi-row large battery module connecting piece;

[0022] S05: The electric motion control system servo controls the descent of the separate welding nozzle and presses the connecting piece and the battery cell electrode; the laser system control system adjusts the emission angle of the gauging head, and the gauging head emits laser welding until the first welding point is completed, and then the gauging head stops emitting laser.

[0023] S06: Repeat the above steps to weld the next welding point until all the welding points of the multi-row large battery module connecting pieces (X) are welded. n ,Y n Z n (n=1,2...N) All welding is completed.

[0024] Compared with the prior art, the significant advantages of this invention are:

[0025] (1) A new laser welding complete set of equipment was designed, which realizes the automation and integration of multi-row large battery module connecting piece feeding, weld point visual positioning and welding processing, improves production speed and overall output, realizes the separation of manual feeding station and processing station for multi-row large battery modules, and improves equipment safety.

[0026] (2) A new type of split welding nozzle was designed, which splits the welding nozzle into multiple detachable independent modules such as nitrogen blowing assembly, dust extraction pipe, and air knife, reducing the replacement cost of vulnerable parts of the welding nozzle and improving the equipment changeover efficiency for welding different types of square or cylindrical batteries.

[0027] (3) Adopting a vision-guided multi-component collaborative motion control method, the feedback position of the vision system is decomposed into the Y-axis motion of the workpiece and the collaborative motion of the X-axis and Z-axis of the welding components, thereby improving the motion efficiency of the equipment for large-scale processing operations. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the device in this embodiment;

[0029] Figure 2 This is a three-dimensional structural diagram of the motion platform in this embodiment;

[0030] Figure 3 This is a partially enlarged schematic diagram of the product positioning plate in this embodiment;

[0031] Figure 4 This is a three-dimensional structural diagram of the welding assembly in this embodiment;

[0032] Figure 5This is a three-dimensional structural diagram of the welding module in this embodiment;

[0033] Figure 6 This is a schematic diagram of the exploded structure of the welding module in this embodiment.

[0034] The components include: 1. Motion platform; 2. Welding components; 3. Multi-row large battery modules; 4. Cooling system; 5. Electrical motion control system; 11. Machine base; 12. Height adjustment bolt; 13. Laser system control system; 14. Y-axis module slide; 15. Product positioning plate; 16. Orientation adjustment limit block; 17. Clamping elbow assembly; 18. Upper computer control platform; 151. Multi-level limit threaded hole; 171. Positioning pressure plate; 172-1. Adjustment positioning bolt 1; 172-2. Adjustment positioning bolt 2; 173. Clamping elbow; 173-1. Pressure rod; 21. Fixed frame; 22. X-axis. Modules: 23 Z-axis module, 24 welding module, 241 base plate, 2411 main body, 2412 extension, 241-1 mounting threaded hole, 241-2 light shield, 242 scanning head, 242-1 laser, 243 high-precision depth camera, 243-1 buckle, 244 custom ring surface light source, 244-1 light source bracket, 245 dust extraction pipe, 246 detachable welding nozzle, 246-1 cylinder, 246-2 telescopic rod, 246-3 nozzle plate, 247 nitrogen blowing assembly, 247-1 nitrogen assembly buckle, 248 air knife. Detailed Implementation

[0035] The principle of this invention is as follows: A novel laser welding assembly is designed, which automates and integrates the feeding of connecting pieces for multi-row large battery modules, visual positioning of weld points, and welding processing, thereby improving production speed and overall output. It also separates the manual feeding station from the processing station for multi-row large battery modules, enhancing equipment safety. Furthermore, a novel detachable welding nozzle is designed, disassembling the nozzle into multiple detachable independent modules such as a nitrogen blowing assembly, dust extraction pipe, and air knife. This reduces the replacement cost of vulnerable parts of the welding nozzle and improves the equipment's efficiency in welding different types of batteries, such as prismatic or cylindrical batteries.

[0036] Example 1:

[0037] like Figure 1The diagram shows a laser welding device for connecting pieces of multi-row large battery modules, comprising a motion platform 1, a welding assembly 2, multi-row large battery modules 3, a cooling system 4, and an electrical motion control system 5. The motion platform 1 is used to place and move the multi-row large battery modules 3. The welding assembly 2 is mainly used for automatic detection of the welding position of the multi-row large battery modules 3 and automatic laser welding processing. The multi-row large battery modules 3 are the workpieces to be welded and are placed on the product positioning plate 15 of the machine base 11. The cooling system 4 is located around the motion platform and is mainly used to reduce the internal temperature of the laser equipment during the welding process. The electrical motion control system 5 is located around the motion platform and is mainly used for the logical functions and electrical integration control of the various modules of the laser welding device.

[0038] like Figure 2 The image shows the motion platform 1, which includes a machine base 11, height adjustment bolts 12, a laser system control system 13, a Y-axis module slide 14, a product positioning plate 15, an orientation adjustment limit block 16, a clamping elbow assembly 17, and a host computer control platform 18. The machine base 11 is fixedly installed on the ground by the height adjustment bolts 12. The height adjustment bolts 12 are evenly distributed on the bottom of the platform, and the levelness of the machine base 11 is adjusted by adjusting the height adjustment bolts 12. The laser system control system 13 is installed inside the machine base 11 and is mainly used to control the laser and the laser optical path of the whole machine. The Y-axis module slide 14 is fixedly installed on the machine base 11. The product positioning plate 15 is installed on the Y-axis module slide and is fastened to the slider of the Y-axis module slide and the linear module slide plate by threaded connection. The orientation adjustment limit block 16 is fixedly installed on the product positioning plate 15 and is evenly distributed at the four corners of the multi-row large battery module. The orientation adjustment limit block 16 is slidably connected to the product positioning plate 15 and is used to adjust the orientation of the multi-row large battery module 3 in the X-axis and Y-axis directions. The multi-row large battery module 3 has a margin for adjustment in the X-axis direction and is fixed in the Y-axis direction. The clamping elbow assembly 17 is fixedly installed on the product positioning plate 15 and is symmetrically distributed on both sides of the multi-row large battery module 3 along the Y-axis. The host computer control platform 18 is fastened to the machine base 11 by extension bracket and is mainly used for human-computer interaction to set the parameters of the laser system control system 13 and the electrical motion control system.

[0039] like Figure 3The image shown is a partial enlarged view of the product positioning plate 15, which includes multi-stage limiting threaded holes 151. These multi-stage limiting threaded holes 151 are threaded through holes evenly distributed on the product positioning plate 15, used for fastening and positioning the directional adjustment limiting block 16 and the clamping elbow assembly 17. The clamping elbow assembly 17 includes a positioning pressure plate 171, adjusting positioning bolts 172-1 and 172-2, and a clamping elbow 173. The positioning pressure plate 171 is located on both sides of the multi-row large battery modules 3 and is a detachable metal pressure plate with two through holes on the bottom and sides, exhibiting good flatness. The positioning pressure plate 171 is connected to the product positioning plate 15 using adjusting positioning bolts 172-1 and 172-2. This device is used for coarse positioning of a multi-row large battery module 3 in the X-axis direction. The clamping elbow 173 is welded to the positioning plate 171 and threaded to the multi-row large battery module 3. The pressure rod 173-1 is elastically connected to the clamping elbow 173. By adjusting the downward pressing angle of the pressure rod 173-1, the distance between the positioning plate 171 and the multi-row large battery module 3 is adjusted, thereby achieving the limit of the multi-row large battery module 3 in the X-axis direction. By adjusting the connection between the positioning plate 171 and different multi-level limit threaded holes 151, and by flexibly adjusting the distance between the positioning plate 171 and the multi-row large battery module 3 in conjunction with the clamping elbow 173, the degree of freedom of the multi-row large battery module 3 in the X-axis direction is flexibly limited.

[0040] like Figure 4 The welding assembly 2 shown includes a fixed frame 21, an X-axis module 22, a Z-axis module 23, and a welding module 24. The fixed frame 21 is bolted to the machine base 11 and is vertically and symmetrically distributed on both sides of the Y-axis module slide 14. The guide rail of the X-axis module 22 is fixed to the upper surface of the fixed frame 21. The electrical motion control system 5 controls the servo motor of the X-axis module 22 to rotate and drive the lead screw to realize the translation of the slider on the guide rail of the X-axis module 22, so as to realize the precise translation of the slider of the X-axis module 22 in the X-axis direction. The Z-axis module 23 is fixedly installed on the slider of the X-axis module 22 through the extension mechanism. The electrical motion control system 5 controls the servo motor of the Z-axis module 23 to rotate and drive the lead screw to realize the translation of the slider on the guide rail of the Z-axis module 23, so as to realize the precise translation of the slider of the Z-axis module 23 in the Z-axis direction. The welding module 24 is fixedly installed on the slider of the Z-axis module 23. Through the combined movement of the X-axis module 22 and the Z-axis module 23, it reaches the preset or high-precision depth camera 243 feedback X and Z coordinates.

[0041] like Figure 5 and Figure 6The welding module 24 shown includes a substrate 241, a scanning head 242, a high-precision depth camera 243, a custom-designed ring-shaped surface light source 244, a dust extraction pipe 245, a detachable welding nozzle 246, a nitrogen blowing assembly 247, and an air knife 248. The substrate 241 includes a main body 2411 and an extension 2412, with the extension 2412 extending downwards from the main body 2411 by a certain distance. The main body 2411 and the extension 2412 are provided with multiple sets of mounting threaded holes 241-1. One side of the substrate 241 is vertically fixed to the slider of the Z-axis module 23 via a threaded connection, and the other side of the substrate 241 is fixedly mounted to the other components of the welding module 24 via a threaded connection. The galvanizing lens 242 is fixedly mounted on the substrate 241 via a threaded connection and is used to adjust the light output direction of the laser 242-1. The high-precision depth camera 243 is fixed on the substrate 241 via a clip 243-1. The high-precision depth camera 243 is adjacent to the galvanizing lens 242 and separated by a light shield 241-2. The custom annular surface light source 244 is located directly below the high-precision depth camera 243 and is fixed on the substrate 241 via a light source bracket 244-1. A custom surface light source with a through hole slightly larger than the aperture of the high-precision depth camera 243 is reserved in the center for high-contrast imaging of the welding position.

[0042] In a preferred embodiment, the dust extraction pipe 245 is fixedly mounted on the substrate 241 by multiple sets of buckles, located behind the diaphragm head 242, and is used for collecting fumes before and during the welding process.

[0043] In a preferred embodiment, the detachable welding nozzle 246 comprises a cylinder 246-1, a telescopic rod 246-2, and a nozzle plate 246-3. The cylinder 246-1 is fixedly mounted on the substrate 241 via a threaded connection and is located directly below the scanning head 242. The telescopic rod 246-2 is directly connected to the piston rod of the cylinder 246-1. The nozzle plate 246-3 is fixedly mounted at the end of the telescopic rod 246-2. The telescopic rod 246-2 of the cylinder controls the rise and fall of the nozzle plate 246-3 according to the Z-axis coordinate fed back by the high-precision depth camera 243, so as to control the gap between the connecting piece to be welded and the multi-row large battery module 3. At the same time, when the shape of the battery module or connecting piece changes, the welding module 24 can be quickly changed by replacing the nozzle plate 246-3, reducing the replacement cost of vulnerable parts.

[0044] In a preferred embodiment, the nitrogen blowing assembly 247 is fixedly mounted on the substrate 241 by the nitrogen assembly clip 247-1, located to the left of the detachable welding nozzle 246, and is used to deliver inert gas during the welding process to protect the welding quality.

[0045] In a preferred embodiment, the air knife 248 is fixedly installed on the module of the vibrating head 242 by a threaded connection, and is used for cleaning dust before and during welding of the welding parts of the multi-row large battery module 3, reducing welding spatter.

[0046] In another embodiment, a laser welding method for connecting pieces of a multi-row large battery module includes the following steps:

[0047] (1) When the equipment is used for the first time or when the equipment is calibrated, adjust the height adjustment bolt 12 at the bottom of the motion platform 1 machine base 11 so that the table surface of the machine base 11 is in the same horizontal plane.

[0048] (2) The multi-row large battery module 3 to be welded is placed manually on the product positioning plate 15 of the machine 11. The orientation adjustment limit block on the product positioning plate 15 is used as the positioning reference in the Y-axis direction to limit the two end faces of the multi-row large battery module 3 in the Y-axis direction.

[0049] (3) Insert the adjusting positioning bolts 172-1 and 172-2 on both sides of the multi-row large battery module 3X direction into the positioning plate 171 and the multi-level limiting threaded hole 151 closest to the multi-row large battery module 3 for coarse positioning of the multi-row large battery module 3X axis direction.

[0050] (4) Adjust the downward pressing angle of the pressure rod 173-1 to adjust the distance between the positioning pressure plate 171 and the multi-row large battery module 3, so as to realize the limit of the multi-row large battery module 3 in the X-axis direction.

[0051] (5) Start the equipment. The electrical motion control system 5 servo controls the movement of the Y-axis module slide 14 of the motion platform 1, and automatically moves the multiple rows of large battery modules 3 on the product positioning plate 15 to the welding station.

[0052] (6) The electrical motion control system 5 servo controls the X-axis module 22 to drive the welding module 24 to move to the set position above the multi-row large battery module 3, and turns on the customized ring surface light source 244 and the high-precision depth camera 243.

[0053] (7) The electrical motion control system 5 servo controls the X-axis module 22 and the Y-axis module slide 14 of the motion platform 1 so that the high-precision depth camera 243 sequentially acquires images of all welding points according to the set position. After the acquisition of images of all welding points is completed, the electrical motion control system 5 servo controls the X-axis module 22 and the Y-axis module slide 14 of the motion platform 1 to return to the initial position set in step (6).

[0054] (8) Perform image stitching and image processing on the acquired images, and calculate the absolute coordinates (X, Y, Z) of all welding points of the multi-row large battery module 3 in the world coordinate system set by the system. n ,Y n Z n (n=1,2...N), where X n Let X be the X-axis coordinate of the nth weld, and Y be the Y-axis coordinate of the weld. nLet Z be the Y-axis coordinate of the nth weld. n The Z-axis coordinate of the nth weld is given, where N is the total number of weld points. The data is then sent and stored on the host computer control platform 18.

[0055] (9) The host computer control platform 18 sends the position (X1, Y1, Z1) of the first welding point of the multi-row large battery module 3 connecting piece to the electrical motion control system 5 through human-computer interaction, and sends the laser welding parameters to the laser system control system 13.

[0056] (10) The electrical motion control system 5 servo controls the X-axis module 22, the Y-axis module slide 14 and the Z-axis module 23 to move together, moving the oscillating head 242 to the first welding point position (X1, Y1, Z1) of the multi-row large battery module 3 connecting piece;

[0057] (11) The electric motion control system 5 servo control separate welding nozzle 246 cylinder 246-1 cylinder extends the telescopic rod 246-2, so that the nozzle plate 246-3 descends and presses the connecting plate and the battery cell pole.

[0058] (12) The electric motion control system 5 servo controls the dust extraction pipe 245 to open the dust extraction, the nitrogen blowing component 247 to open the nitrogen blowing, the air knife 248 to open the air blowing, and the laser system control system 13 to adjust the emission angle of the vibrating head 242. The vibrating head 242 emits laser 242-1 to weld until the first welding point is welded. The vibrating head 242 stops emitting laser 242-1.

[0059] (13) Repeat steps (9)-(12) above to weld the next welding point until the welding points of the connecting pieces of the entire multi-row large battery module 3 are completed (X). n ,Y n Z n (n=1,2...N) All welding is completed;

[0060] (14) The electrical motion control system 5 servo controls the Y-axis module slide 14. The slide automatically moves the multi-row large battery module 3 to the unloading position, and the multi-row large battery module 3 is manually removed to complete the welding.

[0061] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A laser welding device for connecting pieces of multi-row large battery modules, comprising a motion platform and welding components, characterized in that, The motion platform includes a machine base, and a laser system control system is installed inside the machine base. The laser system control system is used to control the laser and the laser optical path of the whole machine. A Y-axis module slide is installed on the machine base. The Y-axis module slide is parallel to the set world coordinate system Y-axis. A product positioning plate is installed on the Y-axis module slide. The welding assembly includes a fixed frame, an X-axis module, a Z-axis module, and a welding module. The fixed frame is mounted on the machine base and is vertically distributed on both sides of the Y-axis module slide. The X-axis module is mounted on the fixed frame. The Z-axis module is fixedly mounted to the slider of the X-axis module via an extension mechanism. The welding module includes a base plate, which is fixedly mounted to the slider of the Z-axis module. The base plate includes a main body and an extension, the extension extending downwards from the main body by a certain distance. The main body and the extension are provided with multiple sets of mounting threaded holes. The main body is equipped with a galvanometer lens for adjusting the laser beam direction. A depth camera is also located adjacent to the galvanometer lens and separated from it by a light-blocking plate. A ring-shaped surface light source is positioned directly below the depth camera for high-contrast imaging of the welding position. The extension section is equipped with a detachable welding nozzle, which includes a nitrogen blowing assembly, a dust extraction pipe, and an air knife. The dust extraction pipe is fixedly mounted on the substrate using multiple sets of U-shaped clips. The nitrogen blowing assembly is fixedly mounted to the extension section using nitrogen assembly clips. The air knife is positioned below the vibrating head; the product positioning plate includes multi-stage limiting threaded holes, which are evenly distributed on the product positioning plate for fastening and positioning the orientation adjustment limiting block and the clamping elbow assembly. The orientation adjustment limiting block is located at the corner of the product positioning plate and is slidably connected to the product positioning plate for orientation adjustment of the multi-row large battery modules in the X-axis and Y-axis directions. The clamping elbow assembly is symmetrically distributed on both sides of the multi-row large battery modules along the Y-axis; the clamping elbow assembly includes a positioning pressure plate. The positioning plate is located on both sides of the multi-row large battery module and has two through holes. The positioning plate is connected to the product positioning plate by adjusting the positioning bolts for coarse positioning of the multi-row large battery module in the X-axis direction. The clamping elbow is set on the positioning plate. The clamping elbow is threadedly fastened to the multi-row large battery module. The clamping elbow is elastically connected to a pressure rod. The distance between the positioning plate and the multi-row large battery module is adjusted by adjusting the downward pressing angle of the pressure rod for limiting the multi-row large battery module in the X-axis direction.

2. The laser welding device for connecting pieces of multi-row large battery modules according to claim 1, characterized in that, The detachable welding nozzle includes a cylinder, a telescopic rod, and a nozzle plate. The cylinder is fixedly installed on the extension of the substrate, located directly below the scanning head. The telescopic rod is connected to the piston rod of the cylinder. The nozzle plate is fixedly installed at the end of the telescopic rod. The telescopic rod controls the nozzle plate to rise and fall according to the Z-axis coordinate fed back by the depth camera.

3. The laser welding device for connecting pieces of multi-row large battery modules according to claim 1, characterized in that, The dust extraction pipe is located behind and to the side of the scanning head.

4. The laser welding device for connecting pieces of multi-row large battery modules according to claim 1, characterized in that, The nitrogen blowing assembly is located on one side of the separate welding nozzle and is used to deliver inert gas.

5. The laser welding device for connecting pieces of multi-row large battery modules according to claim 1, characterized in that, The air knife is used for cleaning dust from the welding area before and during welding.

6. The laser welding device for connecting pieces of multi-row large battery modules according to claim 1, characterized in that, The motion platform is equipped with a cooling system and an electrical motion control system. The cooling system is used to reduce the internal temperature of the laser equipment during the welding process, and the electrical motion control system is used for the logical functions and electrical integration control of various modules of the laser welding device.

7. A laser welding method for connecting pieces of multi-row large battery modules, characterized in that, The laser welding apparatus for multi-row large battery module connecting pieces according to any one of claims 1-6 includes the following steps: S01: Control the X-axis module and Y-axis module slides to make the depth camera sequentially acquire images of all welding points according to the set position. After the images of all welding points are acquired, control the X-axis module and Y-axis module slides to return to the set initial position. S02: image stitching and image processing are performed on the collected images, and absolute coordinate positions (X n ,Y n ,Z n ) of all welding points of the multiple rows of large battery modules in a system set world coordinate system are calculated, n = 1, 2...N, wherein X n is an X-axis coordinate of the nth welding point, Y n is a Y-axis coordinate of the nth welding point, Z n is a Z-axis coordinate of the nth welding point, N is a total number of the welding points, and data is sent and saved to an upper computer control platform; S03: The host computer control platform sends the position (X1, Y1, Z1) of the first welding point of the multi-row large battery module connecting piece to the electrical motion control system through human-computer interaction, and sends the laser welding parameters to the laser system control system. S04: The electric motion control system servo controls the combined motion of the X-axis module, Y-axis module slide, and Z-axis module to move the scanning head to the first welding point position (X1, Y1, Z1) of the multi-row large battery module connecting piece. S05: The electric motion control system servo controls the descent of the separate welding nozzle and presses the connecting piece and the battery cell electrode; the laser system control system adjusts the emission angle of the gauging head, and the gauging head emits laser welding until the first welding point is completed, and then the gauging head stops emitting laser. S06: Repeat the above steps to weld the next welding point until all the welding points of the multi-row large battery module connecting pieces (X) are welded. n ,Y n Z n All welding is now complete.

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