Laser welding device and process for FLC and NTC of automobile power battery aluminum base material

Abstract

The application discloses a laser welding device and process for FLC and NTC of an aluminum base material of a car power battery, and the device comprises a bottom plate, a moving support fixedly arranged on the bottom plate, a welding mechanism slidably installed on the moving support, a hollow cylindrical presser foot installed on a laser exit end of the welding mechanism, the hollow cylindrical presser foot being provided with a central through hole coaxially arranged with a laser beam, a visual positioning module coaxially arranged in an optical path of the welding mechanism, an observation visual field of the visual positioning module penetrating through the central through hole of the hollow cylindrical presser foot, a protective gas supply module connected with the hollow cylindrical presser foot and used for providing protective gas into the central through hole, and a vacuum adsorption platform fixedly installed on the bottom plate, an upper surface of the vacuum adsorption platform being provided with a plurality of adsorption holes for adsorbing and fixing workpieces to be welded, and an air path control mechanism being arranged in the vacuum adsorption platform.

Description

Technical Field

[0001] This invention relates to the field of automotive power battery manufacturing and laser welding technology, specifically to a laser welding device and process for aluminum substrates FLC and NTC in automotive power batteries. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the safety and reliability of power batteries have become core concerns for the industry. In a power battery pack, the CCS (Clean Battery System) is a crucial component, typically consisting of an aluminum battery, a flexible circuit board, and an NTC (Natural Temperature Cell) sensor. The FLC (Fluorescent Cell) serves as the signal acquisition circuit and requires a reliable electrical and mechanical connection with the NTC sensor.

[0003] In existing technologies, traditional FPCs use copper foil as the conductive layer material, which has high material costs and complex processing technology. To reduce costs, the industry has begun to use aluminum foil to replace copper foil to form aluminum substrate FLCs. However, aluminum has high laser reflection efficiency during welding, and the dissimilar metal welding of aluminum and NTC weld joints is prone to generating brittle metal compounds, making the welding unstable.

[0004] In the CCS automated production line, the workpiece to be welded is fixed on the fixture carrier plate, which is then placed on the adsorption platform for welding. Due to the significant differences in FPC specifications corresponding to different battery modules—lengths ranging from 500mm to 1200mm, and even exceeding 1500mm, and widths ranging from 28mm to 250mm—the corresponding fixture carrier plate sizes also vary. In the manufacturing of power batteries, multi-model mixed-line production is commonplace, and the efficiency of model changeover affects the production line utilization rate and delivery capability.

[0005] However, traditional changeover solutions require downtime for each product specification change, necessitating disassembly, reassembly, and fixture adjustments. This results in lengthy changeover times and significantly slows down the production line. While some vacuum adsorption platforms using solenoid valves for partitioned adsorption control can accommodate carriers of different sizes, they require a large number of solenoid valves and independent pipelines, making the system complex and limiting its reliability in the strong electromagnetic interference environment of welding.

[0006] Therefore, it is necessary to provide a laser welding device and process for aluminum substrates FLC and NTC in automotive power batteries to solve the problems mentioned in the background art. Summary of the Invention

[0007] To achieve the above objectives, the present invention provides the following technical solution: a laser welding apparatus for aluminum substrates (FLC) and NTC in automotive power batteries, comprising:

[0008] A base plate, on which a movable support is fixedly mounted;

[0009] The welding mechanism is slidably mounted on the movable support;

[0010] A hollow cylindrical pressure foot is installed at the laser emission end of the welding mechanism. The hollow cylindrical pressure foot has a central through hole, which is coaxially arranged with the laser beam.

[0011] A visual positioning module is coaxially arranged in the optical path of the welding mechanism, and its field of view passes through the central through hole of the hollow cylindrical pressure foot.

[0012] A protective gas supply module, connected to the hollow cylindrical pressure foot, is used to supply protective gas into the central through hole;

[0013] A vacuum adsorption platform is fixedly installed on the base plate. The upper surface of the vacuum adsorption platform is provided with a plurality of adsorption holes for adsorbing and fixing the workpiece to be welded. The vacuum adsorption platform is provided with an air path control mechanism for selectively controlling the opening and closing of the adsorption holes according to the size of the workpiece to be welded.

[0014] Preferably, the workpiece to be soldered includes an aluminum substrate FLC and a pre-made NTC nickel sheet branch. The NTC nickel sheet branch includes a conductive circuit layer made of nickel sheet, a PI insulating film covering both sides of the conductive circuit layer, a soldering window disposed on the PI insulating film, an NTC sensor soldered to the soldering window by SMT process, and soldering fingers extending from the conductive circuit layer.

[0015] Preferably, the diameter of the central through hole is greater than the width of the welding finger.

[0016] Preferably, an auxiliary sleeve is slidably provided at the bottom of the hollow cylindrical presser foot, and a spring is provided between the auxiliary sleeve and the hollow cylindrical presser foot. The spring applies a downward biasing force to the auxiliary sleeve, so that the lower end face of the auxiliary sleeve protrudes from the lower end face of the hollow cylindrical presser foot in a free state. The inner hole of the auxiliary sleeve communicates with the central through hole and forms a recessed hole at the lower end face of the auxiliary sleeve.

[0017] Preferably, the gas path control mechanism includes:

[0018] Multiple gas delivery channels are opened longitudinally along the vacuum adsorption platform. Each gas delivery channel is connected to multiple adsorption holes arranged in the same longitudinal direction, and the multiple gas delivery channels are connected to an external vacuum source through a gas delivery main pipe.

[0019] Multiple control channels are opened laterally along the vacuum adsorption platform. Each control channel is connected to multiple adsorption holes arranged in the same laterally. The control channels and the gas delivery channels are staggered in the height direction, and the control channels are located above the gas delivery channels.

[0020] Rotate the adjusting rod located in each of the control channels, and each adjusting rod independently controls the opening and closing of the adsorption holes in that row;

[0021] A drive rod that is slidably disposed within the vacuum adsorption platform and parallel to the adjusting rod.

[0022] Preferably, multiple drive rods can be connected in groups to several independent support plates, and each support plate is independently slidably installed on one side of the vacuum adsorption platform. By driving multiple groups of support plates to slide, the adsorption holes in each column on the vacuum adsorption platform can be adjusted independently to achieve differentiated control of different adsorption areas.

[0023] Preferably, the adjusting rod is composed of multiple short sections connected in sequence along the axial direction, each short section corresponding to one adsorption hole. A connecting hole is formed on the short section along the radial direction, and a spiral groove and a straight groove are formed on the outer peripheral surface of the short section along its axial direction. A driving block is fixedly provided on the driving rod. The driving block can slide along the spiral groove or the straight groove. When the driving rod slides along the axial direction and the driving block slides along the spiral groove, the driving block drives the corresponding short section to rotate, so that the connecting hole is aligned with or offset from the adsorption hole. When the driving block slides along the straight groove, the axial sliding of the driving rod does not drive the short section to rotate, so that the adjusting rod and the driving rod are in a state of transmission decoupling.

[0024] Preferably, a limiting groove and a limiting rod are respectively provided on the opposite end faces of the short sections. The limiting rod is inserted into the limiting groove and is in clearance fit, so that two adjacent short sections can rotate freely relative to each other within a preset angle range. There is an axial gap between two adjacent short sections that is greater than the width of the driving block, so that the driving block can only engage with the spiral groove or straight groove on one short section at a time.

[0025] Preferably, the adjusting rod is connected to torsion bars at both ends, and the torsion bars are fixedly connected to the short section located at the end. Rotating the torsion bars can drive the adjusting rod to rotate as a whole to control the synchronous opening and closing of the entire row of adsorption holes. When the adjusting rod rotates as a whole, the straight groove faces the driving block, so that the axial sliding of the driving rod no longer drives the short section to rotate.

[0026] The laser welding process for aluminum-based fuel cells (FLC) and NTCs in automotive power batteries includes the following steps:

[0027] S1. Align and stack the welding fingers of the pre-made NTC nickel sheet branch with the reserved welding pads on the aluminum substrate FLC to form a workpiece to be welded. Fix the workpiece to be welded on the fixture carrier plate. Place the fixture carrier plate on the vacuum adsorption platform. Adjust the opening range of the adsorption hole according to the size of the fixture carrier plate through the gas path control device mechanism. Start vacuum adsorption to adsorb and fix the workpiece to be welded.

[0028] S2. Drive the welding mechanism to slide along the movable bracket to the welding position, so that the central through hole of the hollow cylindrical pressure foot is aligned with the welding finger;

[0029] S3. Drive the welding mechanism to descend, so that the lower end face of the hollow cylindrical pressure foot presses against the peripheral area of ​​the welding finger, and the welding finger is tightly attached to the pad of the aluminum substrate FLC.

[0030] S4. The visual positioning module accurately positions the alignment of the pressed welding finger with the solder pad through the central through hole.

[0031] S5. Turn on the protective gas supply module to introduce protective gas into the central through hole, and use the laser welding mechanism to emit a laser beam. The laser beam is perpendicular to the welding finger along the central through hole to perform laser welding. During the welding process, the visual positioning module collects images of the molten pool in real time to monitor the welding quality.

[0032] S6. After welding is completed, turn off the laser and stop the delivery of protective gas. Lift the welding mechanism upward and reset it to release the vacuum adsorption. Remove the welded fixture carrier plate from the vacuum adsorption platform and drive the welding mechanism to move to the next welding station or return to the standby position to wait for the next work cycle.

[0033] Compared with the prior art, the present invention provides a laser welding device and process for aluminum substrates FLC and NTC in automotive power batteries, which has the following advantages:

[0034] First, it provides tight compression without damaging the weld, effectively suppressing weld warping. The hollow cylindrical presser foot works in conjunction with the auxiliary sleeve. Under the action of a spring, the auxiliary sleeve first contacts the periphery of the workpiece for pre-compression, and then the hollow cylindrical presser foot compresses. The countersunk hole provides space for the welding fingers, allowing them to be tightly fitted to the solder pad without excessive direct pressure. This suppresses thermal warping of the ultra-thin nickel sheet and avoids damage or deformation of the welding fingers. The pre-compression function of the auxiliary sleeve effectively flattens the base of the welding fingers, eliminates welding gaps, and improves the bonding quality of the weld joint.

[0035] Secondly, it enables real-time monitoring during welding; the central through hole provides an unobstructed light path, and the vision system can penetrate the pressure foot to observe the molten pool in real time under the pressure state, shifting quality control from "post-weld" to "during welding" and promptly intercepting welding defects.

[0036] Third, it effectively confines spatter and heat; welding spatter is confined inside by the central through hole and the countersunk hole, avoiding contamination of the device; the semi-enclosed chamber concentrates heat and has a small heat-affected zone, protecting the PI insulating film from heat damage.

[0037] Fourth, the rotating friction has a long service life and the pure mechanical design ensures high reliability. The air circuit control mechanism adopts a short-section rotating adjustment method, which controls the opening and closing of the adsorption hole through the rotating friction pair. The friction at the rotating pair is extremely small, resulting in almost no wear in production lines with frequent model changes and a long service life. The overall structure is purely mechanical, and a single main air circuit combined with a single drive source can achieve full distribution. It is not affected by the strong electromagnetic interference of laser welding, has zero pipeline leakage risk, and low maintenance costs.

[0038] Fifth, modular and independent control ensures high changeover efficiency; multiple drive rods can be grouped and connected to independent modular support plates, each of which slides independently, enabling differentiated and independent control of the adsorption holes in different areas of the same adsorption platform; when multiple jig carrier plates of different specifications need to be placed on the production line at the same time, the adsorption range of each area can be adjusted independently, and the isolation row can physically isolate the corresponding areas; each independent adsorption area shares the same vacuum adsorption source, making changeover operation simple, adapting to the needs of multi-station parallel welding, and significantly improving changeover efficiency. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0040] Figure 2 This is a schematic diagram of the vacuum adsorption platform in this invention;

[0041] Figure 3 for Figure 2 Enlarged schematic diagram of section A in the middle;

[0042] Figure 4 This is a schematic diagram of the internal structure of the vacuum adsorption platform in this invention;

[0043] Figure 5 This is a schematic diagram of the hollow cylindrical pressure foot in this invention;

[0044] Figure 6 This is a schematic diagram of the adjusting rod in this invention;

[0045] Figure 7 This is a schematic diagram of the structure in this invention where the drive rod drives the short section to rotate;

[0046] Figure 8 This is a schematic diagram of the overall rotation structure of the torsion bar driven adjusting rod in this invention;

[0047] Figure 9 This is a schematic diagram of the NTC nickel sheet branch structure in this invention. Figure 1 ;

[0048] Figure 10 This is a schematic diagram of the NTC nickel sheet branch structure in this invention. Figure 2 ;

[0049] Figure 11This is a schematic diagram of the modular, partitioned, and independently controlled structure of the adsorption platform in this invention. Figure 1 ;

[0050] Figure 12 This is a schematic diagram of the modular, partitioned, and independently controlled structure of the adsorption platform in this invention. Figure 1 ;

[0051] In the diagram: 100, jig carrier plate; 1, base plate; 11, movable support; 2, welding mechanism; 3, hollow cylindrical pressure foot; 31, central through hole; 32, complex sleeve; 33, countersunk hole; 4, vacuum adsorption platform; 41, adsorption hole; 42, gas path control mechanism; 421, gas delivery channel; 422, control channel; 423, adjusting rod; 424, drive rod; 425, short section; 426, connecting hole; 427, spiral groove; 428, torsion bar; 429, straight groove; 43, support plate; 5, NTC nickel sheet branch; 51, conductive circuit layer; 52, PI insulating film; 521, welding window; 53, NTC sensor; 54, welding finger. Detailed Implementation

[0052] Please see Figures 1-12 In this embodiment of the invention, the laser welding device for aluminum substrates FLC and NTC of automotive power batteries includes a base plate 1, a movable bracket 11, a welding mechanism 2, a hollow cylindrical presser foot 3, a vision positioning module, a protective gas supply module, a vacuum adsorption platform 4, and a gas path control mechanism 42 disposed in the vacuum adsorption platform 4.

[0053] In this embodiment, the base plate 1 serves as the installation foundation for the entire device. It is made of high-strength aluminum alloy or stainless steel and has sufficient rigidity and stability. A movable bracket 11 is fixedly installed on the top of the base plate 1. The movable bracket 11 is preferably a linear guide rail type bracket, which includes two parallel linear slide rails and a servo motor and ball screw pair for driving.

[0054] Furthermore, the welding mechanism 2 is slidably mounted on the movable support 11 via a slider, and can be precisely moved to different welding positions along the movable support 11 under the drive of a servo motor.

[0055] In a preferred embodiment, the hollow cylindrical pressure foot 3 is mounted on the laser emission end of the welding mechanism 2 and can be raised and lowered together with the welding mechanism 2; the hollow cylindrical pressure foot 3 has a central through hole 31 extending along its axial direction, which is coaxially arranged with the laser beam; the hollow cylindrical pressure foot 3 is preferably made of tungsten steel or zirconium oxide ceramic, which has excellent high temperature resistance and hardness; and the inner wall of the central through hole 31 is mirror polished to reduce the adhesion of welding spatter.

[0056] Furthermore, the visual positioning module is coaxially arranged in the optical path of the welding mechanism 2, including a CCD industrial camera and a ring illumination source; the observation field of the CCD industrial camera passes through the central through hole 31 of the hollow cylindrical pressure foot 3, and can directly observe the welding point area under the pressure state; the ring illumination source is arranged around the central through hole 31 to provide uniform coaxial illumination for the vision system.

[0057] Furthermore, the protective gas supply module is connected to the protective gas inlet hole on the side wall of the hollow cylindrical pressure foot 3 via a pipeline, and is used to supply protective gas into the central through hole 31; the protective gas is preferably argon or nitrogen.

[0058] In a preferred embodiment, the vacuum adsorption platform 4 is fixedly installed on the base plate 1, and its upper surface is provided with a plurality of adsorption holes 41 for adsorbing and fixing the workpiece to be welded; the vacuum adsorption platform 4 is provided with an air path control mechanism 42 for selectively controlling the opening and closing of the adsorption holes 41 according to the size of the workpiece to be welded.

[0059] In this embodiment, the workpiece to be welded includes an aluminum substrate FLC and a pre-made NTC nickel sheet branch 5. The aluminum substrate FLC is made by replacing the original copper material with aluminum material, which greatly reduces the cost of automotive CCS. The fixture carrier plate 100 that carries the workpiece to be welded is a standard rectangular carrier plate.

[0060] Furthermore, the specific structure of the NTC nickel sheet branch 5 is as follows: a conductive circuit layer 51 is made of pure nickel sheet with a thickness of 0.1 mm. The upper and lower surfaces of the conductive circuit layer 51 are sealed by pressing with a PI insulating film 52. The PI insulating film 52 has a thickness of 0.075 mm and has excellent insulation and high temperature resistance. At the position where the NTC sensor 53 needs to be soldered, a soldering window 521 is opened on the PI insulating film 52 to expose the nickel sheet. Using SMT surface mount technology, the NTC sensor 53 is precisely mounted at the soldering window 521, and the electrical and mechanical connection is completed by reflow soldering.

[0061] Furthermore, one end of the conductive circuit layer 51 extends into an exposed nickel sheet to form a welding finger 54, which is used for subsequent laser welding to the pads on the aluminum substrate FLC.

[0062] It is important to note that this pre-fabricated NTC nickel strip branch first solders the NTC sensor onto the nickel strip circuit using a mature SMT process, and then solders the nickel strip circuit to the aluminum substrate FLC. Compared to the traditional method of directly soldering the NTC sensor to the aluminum substrate FLC, this "nickel strip transition" structure transforms the difficult-to-solder aluminum-copper / NTC dissimilar metal interface into a more mature and reliable nickel-aluminum interface, effectively reducing the impact of brittle intermetallic compounds generated during dissimilar metal welding on the solder joint strength. The nickel strip, as an intermediate transition layer, has physical and chemical properties between the aluminum-based FLC and the NTC sensor, acting as a metallurgical compatibility bridge. While reducing the welding difficulty, it significantly improves the mechanical strength and electrical conductivity stability of the solder joint.

[0063] In this embodiment, an auxiliary sleeve 32 is slidably sleeved on the bottom of the hollow cylindrical presser foot 3; a spring is provided between the auxiliary sleeve 32 and the hollow cylindrical presser foot 3, and the spring can apply a downward biasing force to the auxiliary sleeve 32; so that in the free state, that is, when the hollow cylindrical presser foot 3 is not pressing the workpiece, the lower end face of the auxiliary sleeve 32 protrudes from the lower end face of the hollow cylindrical presser foot 3 under the action of the spring, and the inner hole of the auxiliary sleeve 32 is connected to the central through hole 31. Since the lower end face of the auxiliary sleeve 32 is lower than the lower end face of the hollow cylindrical presser foot 3, a recessed space, namely the sinkhole 33, is naturally formed at the lower end face of the auxiliary sleeve 32.

[0064] Specifically, when the welding mechanism 2 descends to press down, the lower end face of the auxiliary sleeve 32 first contacts the PI insulating film area around the welding finger 54 and presses it down; as the welding mechanism 2 continues to descend, the spring is further compressed, and the lower end face of the hollow cylindrical presser foot 3 gradually approaches the peripheral area of ​​the welding finger 54, finally completing the pressing; during this process, the countersunk hole 33 provides a space for the welding finger 54 to accommodate it, preventing the welding finger 54 from being deformed or damaged by excessive direct pressure; at the same time, the auxiliary sleeve 32 first presses down the peripheral area, which can effectively flatten the root of the welding finger 54, so that it fits tightly with the pad of the aluminum substrate FLC, eliminating welding gaps.

[0065] In addition, the welding spatter generated during the welding process is confined inside by the central through hole 31 and the recessed hole 33, which will not contaminate the surrounding devices and optical lenses. The central through hole 31 and the recessed hole 33 together form a miniature semi-enclosed chamber, which concentrates the welding heat and has a small heat-affected zone, effectively protecting the PI insulating film from heat damage.

[0066] In this embodiment, the gas path control mechanism 42 is a purely mechanical structure, including a gas delivery channel 421, a control channel 422, an adjusting rod 423, and a driving rod 424; the gas delivery channel 421 has multiple channels along the longitudinal direction of the vacuum adsorption platform 4, and each gas delivery channel 421 is connected to multiple adsorption holes 41 arranged in the same longitudinal direction; the ends of all gas delivery channels 421 converge into a gas delivery main pipe, and the gas delivery main pipe is connected to an external vacuum source through a main valve.

[0067] Furthermore, multiple control channels 422 are opened laterally along the vacuum adsorption platform 4, and each control channel 422 is connected to multiple adsorption holes 41 arranged in the same laterally. The control channels 422 and the gas supply channels 421 are staggered in the height direction, with the control channels 422 located above the gas supply channels 421. The two are connected to the corresponding adsorption holes 41 through a vertical air hole at their intersection. Each control channel 422 is rotatably equipped with an adjusting rod 423, which is used to independently control the on / off state of all adsorption holes 41 in that row. The adjusting rod 423 is formed by multiple short sections 425 connected axially in sequence, with each short section 425 corresponding to an adsorption hole 41. A connecting hole 426 is opened radially on the short section 425, and the axis of the connecting hole 426 intersects perpendicularly with the axis of the short section 425. Spiral grooves 427 and straight grooves 429 are respectively opened on the outer circumferential surface of the short section 425 along its axis, and the two are arranged at intervals along the circumference of the short section 425.

[0068] In a preferred embodiment, a drive rod 424, parallel to the adjusting rod 423, is slidably mounted on the side of the vacuum adsorption platform 4, and a drive block is fixedly mounted on the drive rod 424. The drive block can be accommodated in the spiral groove 427 or straight groove 429 of the corresponding short section 425. When the drive rod 424 slides axially and the drive block moves along the spiral groove 427, the drive block forces the short section 425 to rotate around its axis, thereby aligning or offsetting the connecting hole 426 with the corresponding adsorption hole 41 below. When the connecting hole 426 is aligned with the adsorption hole 41, the adsorption hole 41 is in a conductive state, and the vacuum negative pressure can act on the surface of the workpiece. When the connecting hole 426 is offset from the adsorption hole 41, the adsorption hole 41 is blocked by the outer wall of the short section 425 and is in a closed state.

[0069] When the drive block moves along the straight groove 429, the axial sliding of the drive rod 424 does not drive the short section 425 to rotate, and the adjusting rod 423 and the drive rod 424 are in a state of transmission decoupling. The significance of this design is that when the adjusting rod 423 is rotated to the whole row closed position by the torsion bar 428, the straight groove 429 faces the drive block, and thereafter the axial sliding of the drive rod 424 no longer affects the state of the short section 425 of that row, keeping the whole row closed.

[0070] In this embodiment, a limiting groove and a limiting rod are respectively provided on the opposite end faces of two adjacent short sections 425; the limiting groove is an arc-shaped groove, and the limiting rod is a cylindrical protrusion that is inserted into the limiting groove with clearance fit. This design allows the two adjacent short sections 425 to rotate relatively freely within a preset angle range, i.e., within the arc range of the limiting groove. When adjusting a single section, the torque will not be transmitted to the adjacent short sections.

[0071] Furthermore, there is an axial gap between two adjacent short sections 425 that is greater than the width of the drive block. This gap is preferably 1.2 to 1.5 times the width of the drive block. This ensures that when the drive rod 424 slides, the drive block can only engage with the spiral groove 427 on one short section 425 at a time, and will not drive two short sections at the same time, thus achieving precise single-section control during "column adjustment".

[0072] In this embodiment, torsion bars 428 are connected to both ends of the adjusting rod 423. The torsion bars 428 are circumferentially fixed to the short sections 425 located at the ends by means of key connection or pin connection. When the operator rotates the torsion bar 428 at either end, the short section 425 at the end is driven to rotate. Through the contact between the limiting rod and the end of the limiting groove, the torque is transmitted along the entire adjusting rod 423, so that all the short sections 425 rotate synchronously. In this way, the entire row of adsorption holes 41 can be opened or closed at the same time, that is, the "row blocking" function can be realized.

[0073] When the adjusting rod 423 is rotated to the closed position of the entire row, the straight grooves 429 on each short section 425 are uniformly oriented towards the driving block. At this time, the axial sliding of the driving rod 424 no longer drives the short section 425 of that row to rotate, and the adsorption hole 41 of that row remains closed and is not affected by the column adjustment operation.

[0074] In this embodiment, multiple drive rods 424 can be connected in groups to several independent support plates 43; each support plate 43 is independently slidably installed on one side of the vacuum adsorption platform 4 and can be driven by an independent hydraulic cylinder, air cylinder or manual screw; by driving each support plate 43 to slide, each column of adsorption holes 41 on the vacuum adsorption platform 4 can be adjusted independently in groups to achieve differentiated control of different adsorption areas.

[0075] For example, when two fixture carrier plates 100 of different specifications need to be placed simultaneously on the same vacuum adsorption platform 4, several drive rods 424 on the left side can be connected to the first support plate, and several drive rods 424 on the right side can be connected to the second support plate; the first support plate can slide independently to adjust the column opening range of the adsorption area on the left side to adapt to the first carrier plate; the second support plate can slide independently to adjust the column opening range of the adsorption area on the right side to adapt to the second carrier plate; the isolation column between the two carrier plates can be closed as a whole by the corresponding torsion rod 428 to achieve physical isolation of the adsorption areas, and each independent adsorption area can share the same vacuum adsorption source.

[0076] In practice, firstly, rotate the torsion bar 428 corresponding to each row to rotate the row that needs to be opened to the open position (spiral groove 427 facing the drive block) and rotate the row that needs to be closed to the closed position (straight groove 429 facing the drive block). At this time, the adjustment rod 423 of the closed row is decoupled from the drive rod 424. Then, according to the column range covered by the fixture carrier plate 100, drive the corresponding support plate 43 to slide. The sliding of the support plate 43 can drive the connected drive rod 424 to move synchronously. The drive block moves along the spiral groove 427 of the open row, driving the short section 425 of the uncovered column to rotate, thereby causing the connecting hole 426 on the short section 425 of the uncovered column to be misaligned with the corresponding adsorption hole 41, thereby closing the adsorption hole 41 of that column, so as to complete the precise adjustment of the adsorption range of the adsorption platform 4.

[0077] It should be noted that in the initial state, the connecting hole 426 and the adsorption hole 41 are in a conductive state, and the limiting rods on the two adjacent short sections 425 are located at the ends of the limiting grooves. At this time, the limiting rods can rotate to the other end of the limiting grooves. This rotation direction is consistent with the direction in which the driving block drives the short section 425 to rotate when sliding along the spiral groove 427. The rotation adjustment of the torsion bar 428 is opposite to this rotation direction. That is, in the initial state, the torsion bar 428 can directly drive the entire adjusting rod 423 to rotate so that the entire row of adsorption holes 41 are closed. After rotation, the straight groove 429 will face the driving block. When it is necessary to reopen the closed adsorption holes 41 in the row, it is only necessary to rotate the adjusting rod 423 to the initial position in this direction. Correspondingly, the axial gap formed between the two adjacent short sections 425 provides a storage space for the driving block. That is, the driving block will detach from the short section 425. This further allows the driving block to still rotate the entire adjusting rod 423 after adjusting the rotation of the corresponding short section 425, and the two will not conflict.

[0078] To better illustrate the advantages of the gas path control mechanism 42 of the present invention compared with other purely mechanical solutions, an adsorption platform solution using a single row of solid rods to block the gas path is provided below for comparison.

[0079] The structure of this comparative scheme is as follows: multiple control channels are opened horizontally within the vacuum adsorption platform, each control channel corresponding to a row of adsorption holes. An air intake channel extending in the same direction is set parallel to the control channel directly below it. The control channels and air intake channels are connected to the corresponding adsorption holes via vertical air holes at their intersection. A solid sealing rod is slidably installed within each control channel. The solid sealing rod can slide axially, and the connection between the adsorption holes and the air intake channel can be adjusted by driving this solid sealing rod to slide. The method for controlling the adsorption range is to adjust the opening and closing of the air holes by driving the solid sealing rod to cover the range of the control channel. That is, driving a single solid sealing rod to completely cover the control channel closes all air holes in that row; driving multiple solid sealing rods to slide the same distance covers the same range of the corresponding control channel, thus achieving the opening range of the adsorption holes in the corresponding column of different control channels, thereby also achieving the adjustment of the adsorption range.

[0080] However, in actual use, this solution will cause sealing wear due to long-stroke sliding friction: the solid sealing rod needs to slide along the control channel axis during adjustment. Even when two solid sealing rods are symmetrically arranged, its sliding stroke still needs to cover half the length of the adsorption platform. The long-stroke reciprocating sliding will continuously rub against the sealing ring and inner wall surface. In production lines with frequent model changes, as the number of adjustments accumulates, its sealing performance will gradually decrease, leading to an increase in vacuum leakage rate and insufficient adsorption force. Consequently, it needs to be replaced regularly, resulting in high maintenance costs.

[0081] In contrast, this embodiment uses the rotation of the short section 425 to control the opening and closing of the adsorption hole 41. The friction at the rotating joint is extremely small, and there is almost no wear during the adjustment process. Its service life is far longer than that of the sliding scheme. As for the wear of the drive block and the spiral groove 427 on the drive rod 424, they are not precisely matched. The purpose of the drive block is only to drive the short section 425 to rotate so that the connecting hole 426 is misaligned or aligned with the adsorption hole 41. This misalignment range can be designed to be larger, that is, to allow the generation of frictional equivalent. Therefore, the wear of the drive rod 424 will not affect the overall adjustment accuracy of the adsorption platform 4. Moreover, compared with the solenoid valve control scheme, this purely mechanical adjustment structure is completely unaffected by electromagnetic interference, which can ensure that it is always accurately adjusted. It is especially suitable for the actual needs of the CCS automated production line for power batteries with multiple varieties and frequent model changes.

[0082] The laser welding process for aluminum-based fuel cells (FLC) and NTCs in automotive power batteries includes the following steps:

[0083] S1. Align and stack the welding fingers 54 of the pre-made NTC nickel sheet branch 5 with the reserved welding pads on the aluminum substrate FLC to form a workpiece to be welded; fix the workpiece to be welded on the fixture carrier plate 100, place the fixture carrier plate 100 on the vacuum adsorption platform 4, operate the gas path control mechanism 42 according to the aforementioned adjustment sequence, adjust the opening range of the adsorption hole 41 according to the size of the fixture carrier plate 100, start vacuum adsorption to adsorb and fix the fixture carrier plate 100. The bottom surface of the fixture carrier plate 100 is a regular rectangular plane, which cooperates with the upper surface of the vacuum adsorption platform 4. The adsorption force is evenly distributed on the entire bottom surface of the fixture carrier plate 100, providing stable support for subsequent welding.

[0084] S2. Drive the welding mechanism 2 to slide along the movable bracket 11 to the welding position, so that the central through hole 31 of the hollow cylindrical presser foot 3 is roughly aligned with the area where the welding finger 54 is located.

[0085] S3. The drive welding mechanism 2 descends, and the auxiliary sleeve 32 first contacts and presses the PI insulating film area around the welding finger 54. As it continues to descend, the spring is compressed, and the lower end face of the hollow cylindrical pressure foot 3 presses against the area around the welding finger 54. The countersunk hole 33 accommodates the welding finger 54, preventing it from being subjected to excessive pressure, while ensuring it fits tightly against the pad of the aluminum substrate FLC. Since the fixture carrier plate 100 is vacuum-adsorbed and firmly attached to the platform, the pressure applied by the pressure foot will not cause the carrier plate to elastically sink, ensuring the precise position of the laser focus.

[0086] S4. The visual positioning module takes pictures and analyzes the alignment of the welding finger 54 with the welding pad under the pressure state through the central through hole 31. If the position deviation is detected to be beyond the allowable range, the system drives the welding mechanism 2 to make fine adjustments and corrections.

[0087] S5. Turn on the protective gas supply module and introduce protective gas into the central through hole 31. The laser generator emits a laser beam, which is perpendicular to the welding finger 54 along the central through hole 31. During the welding process, the vision positioning module collects images of the molten pool in real time, monitors the shape, brightness and spatter of the molten pool, and performs welding quality monitoring. If an abnormality is detected, the system can immediately interrupt the welding and sound an alarm.

[0088] S6. After welding is completed, turn off the laser and stop the supply of protective gas. After a delay of 2 seconds, the welding mechanism 2 is lifted up and reset. Release the vacuum adsorption and remove the completed welding fixture carrier plate 100 from the vacuum adsorption platform 4 to the next process. Drive the welding mechanism 2 to move along the moving bracket 11 to the next welding station or return to the standby position to wait for the next work cycle.

[0089] As an extended embodiment of the present invention, the above-mentioned laser welding device can be further integrated into a fully automated welding production line. The production line includes a conveyor line, multiple welding stations spaced apart along the conveyor line, and loading and unloading robots respectively located at the input and output ends of the conveyor line. Each welding station is equipped with the laser welding device described in the above embodiment. The conveyor line sequentially transports the fixture carrier plate carrying the workpiece to be welded to the vicinity of each station, where the loading robot picks it up and places it on the vacuum adsorption platform of an idle station. After welding is completed, the unloading robot removes the fixture carrier plate and returns it to the conveyor line. Each welding station operates independently and in parallel, without interfering with each other, thus significantly improving welding efficiency.

[0090] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A laser welding device for FLC and NTC of an aluminum substrate of a car power battery, characterized in that, include: A base plate (1) is fixedly provided with a movable bracket (11); The welding mechanism (2) is slidably mounted on the movable support (11); A hollow cylindrical pressure foot (3) is installed at the laser emission end of the welding mechanism (2). The hollow cylindrical pressure foot (3) has a central through hole (31), which is coaxially arranged with the laser beam. The visual positioning module is coaxially arranged in the optical path of the welding mechanism (2), and its field of view passes through the central through hole (31) of the hollow cylindrical pressure foot (3); The protective gas supply module is connected to the hollow cylindrical pressure foot (3) and is used to supply protective gas into the central through hole (31); A vacuum adsorption platform (4) is fixedly installed on the base plate (1). The upper surface of the vacuum adsorption platform (4) is provided with a plurality of adsorption holes (41) for adsorbing and fixing the workpiece to be welded. The vacuum adsorption platform (4) is provided with an air path control mechanism (42) for selectively controlling the opening and closing of the adsorption holes (41) according to the size of the workpiece to be welded.

2. The laser welding device of the automobile power battery aluminum base material FLC and NTC according to claim 1, characterized in that, The workpiece to be soldered includes an aluminum substrate FLC and a pre-made NTC nickel sheet branch (5). The NTC nickel sheet branch (5) includes a conductive circuit layer (51) made of nickel sheet, a PI insulating film (52) covering both sides of the conductive circuit layer (51), a soldering window (521) disposed on the PI insulating film (52), an NTC sensor (53) soldered to the soldering window (521) by SMT process, and a soldering finger (54) extending from the conductive circuit layer (51).

3. The laser welding device of the FLC and NTC of the automobile power battery aluminum base material according to claim 2, characterized in that, The diameter of the central through hole (31) is greater than the width of the welding finger (54).

4. The laser welding device of the FLC and NTC of the automobile power battery aluminum base material according to claim 1, characterized in that, An auxiliary sleeve (32) is slidably provided at the bottom of the hollow cylindrical presser foot (3). A spring is provided between the auxiliary sleeve (32) and the hollow cylindrical presser foot (3). The spring applies a downward biasing force to the auxiliary sleeve (32), so that the lower end face of the auxiliary sleeve (32) protrudes from the lower end face of the hollow cylindrical presser foot (3) in a free state. The inner hole of the auxiliary sleeve (32) is connected to the central through hole (31) and a recessed hole (33) is formed at the lower end face of the auxiliary sleeve (32).

5. The laser welding device of the automobile power battery aluminum base material FLC and NTC according to claim 1, characterized in that, The gas path control mechanism (42) includes: Multiple gas delivery channels (421) are opened longitudinally along the vacuum adsorption platform (4). Each gas delivery channel (421) is connected to multiple adsorption holes (41) arranged in the same longitudinal direction, and the multiple gas delivery channels (421) are connected to an external vacuum source through a gas delivery main pipe. Multiple control channels (422) are opened laterally along the vacuum adsorption platform (4). Each control channel (422) is connected to multiple adsorption holes (41) arranged in the same laterally. The control channels (422) and the gas delivery channels (421) are staggered in the height direction, and the control channels (422) are located above the gas delivery channels (421). Rotate the adjusting rod (423) located in each of the control channels (422), and each adjusting rod (423) independently controls the opening and closing of the adsorption hole (41) in that row; A drive rod (424) is slidably disposed within the vacuum adsorption platform (4) and parallel to the adjusting rod (423).

6. The laser welding device of the FLC and NTC of the automobile power battery aluminum base material according to claim 5, characterized in that, Multiple drive rods (424) can be connected in groups to several independent support plates (43). Each support plate (43) is independently slidably installed on one side of the vacuum adsorption platform (4). By driving multiple groups of support plates (43) to slide, the adsorption holes (41) in each column on the vacuum adsorption platform (4) can be adjusted independently in groups to achieve differentiated control of different adsorption areas.

7. The laser welding device of the FLC and NTC of the automobile power battery aluminum base material according to claim 5, characterized in that, The adjusting rod (423) is formed by a plurality of short sections (425) connected in sequence along the axial direction. Each short section (425) corresponds to one adsorption hole (41). A connecting hole (426) is opened radially on the short section (425). A spiral groove (427) and a straight groove (429) are opened axially on the outer circumferential surface of the short section (425). A driving block is fixedly installed on the driving rod (424). The driving block can slide along the spiral groove (427) or the straight groove (429). When the drive rod (424) slides axially and the drive block slides along the spiral groove (427), the drive block drives the corresponding short section (425) to rotate, so that the connecting hole (426) is aligned or offset from the adsorption hole (41). When the drive block slides along the straight groove (429), the axial sliding of the drive rod (424) does not drive the short section (425) to rotate, so that the adjusting rod (423) and the drive rod (424) are in a state of transmission decoupling.

8. The laser welding device of the FLC and NTC of the automobile power battery aluminum base material according to claim 7, characterized in that, Limiting grooves and limiting rods are respectively provided on the opposite end faces of the short sections (425). The limiting rods are inserted into the limiting grooves and are in clearance fit, so that two adjacent short sections (425) can rotate freely relative to each other within a preset angle range. There is an axial gap between two adjacent short sections (425) that is greater than the width of the driving block, so that the driving block can only cooperate with the spiral groove (427) or straight groove (429) on one short section (425) at a time.

9. The laser welding device of the FLC and NTC of the automobile power battery aluminum base material according to claim 7, characterized in that, The adjusting rod (423) is connected to torsion bars (428) at both ends. The torsion bars (428) are fixedly connected to the short section (425) located at the end. Rotating the torsion bars (428) can drive the adjusting rod (423) to rotate as a whole to control the synchronous opening and closing of the entire row of adsorption holes (41). When the adjusting rod (423) rotates as a whole, the straight groove (429) faces the driving block, so that the axial sliding of the driving rod (424) no longer drives the short section (425) to rotate.

10. The laser welding process of the FLC and NTC of the aluminum base material of the automobile power battery as claimed in claim 2, characterized in that, Includes the following steps: S1. The welding fingers (54) of the pre-made NTC nickel sheet branch (5) are aligned and stacked with the reserved welding pads on the aluminum substrate FLC to form a workpiece to be welded. The workpiece to be welded is fixed on the fixture carrier plate. The fixture carrier plate is placed on the vacuum adsorption platform (4). The opening range of the adsorption hole (41) is adjusted according to the size of the fixture carrier plate by the gas path control device mechanism (42). Vacuum adsorption is started to adsorb and fix the workpiece to be welded. S2. Drive the welding mechanism (2) to slide along the movable bracket (11) to the welding position, so that the central through hole (31) of the hollow cylindrical presser foot (3) is aligned with the welding finger (54); S3. Drive the welding mechanism (2) to descend, so that the lower end face of the hollow cylindrical presser foot (3) presses against the peripheral area of ​​the welding finger (54), and the welding finger (54) is tightly attached to the pad of the aluminum substrate FLC. S4. The visual positioning module accurately positions the alignment of the pressed welding finger (54) with the welding pad through the central through hole (31). S5. Turn on the protective gas supply module to introduce protective gas into the central through hole (31), and use the laser welding mechanism (2) to emit a laser beam. The laser beam is perpendicularly irradiated onto the welding finger (54) along the central through hole (31) to perform laser welding. During the welding process, the visual positioning module collects images of the molten pool in real time to monitor the welding quality. S6. After welding is completed, turn off the laser and stop the delivery of protective gas. Lift the welding mechanism (2) upward to reset it, release the vacuum adsorption, remove the completed welding fixture carrier from the vacuum adsorption platform (4), and drive the welding mechanism (2) to move to the next welding station or return to the standby position to wait for the next work cycle.

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