A soft-pack battery module tab welding quality detection system and method

Abstract

The present invention discloses a soft-pack battery module tab welding quality detection system and method, which belongs to the field of new energy vehicles. The battery module walking assembly is installed on the first guide rail on the machine platform, the leveling assembly and the detection assembly are installed on the same side of the first guide rail, the ultrasonic welding machine welding head in the leveling assembly and the line laser measuring instrument sensing head in the detection assembly are both located above the first guide rail, and the sensing head is set at the process downstream position of the welding head; the present invention can flexibly set the relevant control program according to the different weld positions and quantities of different battery modules, and by setting the downward pressure of the welding head, etc., the welding head is vibrated on the busbar near the weld, loosening and lifting the poorly welded welds, and judging whether the weld is welded by taking pictures and scanning, and judging whether the welding is qualified by measuring the relative height difference between the tab and the busbar, thereby ensuring that the tab weld after laser welding meets the requirements of welding position and reliable fitting to the busbar.

Description

Technical Field

[0001] The present invention belongs to the field of new energy vehicles, and in particular relates to a system and method for detecting the welding quality of tabs of a soft-pack battery module. Background Art

[0002] New energy vehicles require the use of various battery packs to provide power sources for the vehicles in a series-parallel manner. The battery cells in the battery pack are in the form of hard shells, soft packs, etc. The present invention is aimed at soft-pack battery cells. After the soft-pack battery cells are assembled into a module, it is generally necessary to connect the tabs to the busbar so that each individual battery cell forms the required series-parallel form to ensure that the module reliably outputs stable DC voltage and capacity. Laser welding is one of the methods currently frequently used. After the tabs are welded to the busbar, it is generally required to inspect the welding parts after the tabs (the tab materials are copper, aluminum, and thin sheets) are welded to the busbar.

[0003] Current testing methods include manually lifting the tab edge for observation and fixing the module to a vibration table for vibration testing. These methods have the following shortcomings:

[0004] (1) Manually lift the edge of the tab and observe that the tab needs to be pressed down to return to a flat state, which is inefficient and prone to fatigue for operators.

[0005] (2) Fixing the module to a vibration table and then performing a vibration test to judge the welding quality is a complicated and time-consuming process, which seriously affects the production rhythm of the module.

[0006] Therefore, there is an urgent need for an automated and efficient method for detecting the welding quality of the tabs and busbars. Summary of the Invention

[0007] The purpose of the present invention is to overcome the defects of the existing technology. In order to solve the problems of low efficiency in manually lifting the edge of the tab for observation, easy fatigue of operators, and the impact of vibration testing on the production rhythm of the module after the module is fixed to a vibration table, a system and method for judging the quality of laser welding of the tabs of a soft-pack battery module are proposed.

[0008] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0009] A soft-pack battery module tab welding quality inspection system, including a machine platform, a battery module walking component, a vibration leveling component, a detection component, a barcode scanner and a host computer;

[0010] The machine is provided with a first guide rail, the battery module walking assembly is installed on the first guide rail, the leveling assembly and the detection assembly are installed on the same side of the first guide rail, the ultrasonic welding machine welding head in the leveling assembly and the line laser measuring instrument sensing head in the detection assembly are located above the first guide rail, and the line laser measuring instrument sensing head is arranged at a process downstream position of the ultrasonic welding machine welding head; the battery module walking assembly, leveling assembly, detection assembly, and barcode scanning gun are all connected to the host computer;

[0011] The battery module walking assembly includes a first servo motor, a first screw slider pair and a first mounting platform fixed on the first screw slider pair. The first screw slider pair is installed on the first guide rail, and the first servo motor is connected to the first screw slider pair.

[0012] As a preferred embodiment of the present invention, the first mounting platform of the battery module walking assembly includes an upper plate and a lower plate, the lower plate is fixed on the first screw slider pair, the upper plate is mounted on the lower plate, and the upper plate is rotatable.

[0013] As a preferred embodiment of the present invention, a lifting plate is installed on the machine platform. When the first mounting platform moves above the lifting plate, the lifting plate can pass through the lower plate of the first mounting platform and drive the upper plate of the first mounting platform to rise, fall and rotate.

[0014] As a preferred embodiment of the present invention, the vibrating assembly includes an ultrasonic welding machine, a second servo motor, a second lead screw slider pair and a second mounting platform fixed on the second lead screw slider pair; the ultrasonic welding machine is fixed on the second mounting platform; the second lead screw slider pair is installed on the second guide rail on the machine platform, and the second servo motor is connected to the second lead screw slider pair; the second guide rail is perpendicular to the first guide rail.

[0015] As a preferred embodiment of the present invention, the working surface of the ultrasonic welding machine welding head is a plane, and the working surface is a straight and smooth rectangle.

[0016] As a preferred embodiment of the present invention, the detection assembly includes a line laser measuring instrument, a third servo motor, a third lead screw slider pair and a third mounting platform fixed on the third lead screw slider pair; the line laser measuring instrument includes a line laser measuring instrument sensor head and a line laser measuring instrument controller, and the line laser measuring instrument sensor head is fixed on the third mounting platform; the third lead screw slider pair is installed on the third guide rail on the machine platform, and the third servo motor is connected to the third lead screw slider pair; the third guide rail is perpendicular to the first guide rail.

[0017] As a preferred embodiment of the present invention, the ultrasonic welding machine welding head is made of die steel.

[0018] During operation, the ultrasonic welder uses an ultrasonic generator to convert 50Hz mains power into a 20kHz sinusoidal signal. This signal is then converted back into mechanical motion of the same frequency by a transducer. This motion is then transmitted to the welding head, which transfers the received vibration energy to the surface of the busbar to be vibrated. In this area, the vibration energy vibrates the busbar, while the remainder is converted into heat and dissipated. A line laser measuring head takes a photo of the weld and measures the height difference between the tab and the busbar at the set weld location. By comparing this with a set standard value range, it determines whether the weld is in the correct position and whether any loosening has occurred.

[0019] The present invention has the following beneficial effects:

[0020] The present invention can effectively solve the problems of low efficiency in manually tilting the tab edge for observation, easy fatigue of operators, and affecting the production rhythm of the module after the module is fixed to the vibration table for vibration testing. The specific problems are as follows:

[0021] (1) According to the different number of tab welds in different battery modules, the relevant control program can be flexibly set. Once the reference direction is determined, the ultrasonic welding machine will automatically vibrate the busbar at each determined position according to the predetermined program. Since the vibration frequency is very high (much higher than the relevant requirements in the national standard) and the busbar is pressed by the welding head to form a single point of force, the welds with poor welding quality will be completely vibrated open or the edges will be loosened and lifted off the busbar. The height difference is then tested by a line laser measuring instrument and compared with the standard sample to determine whether it is qualified. The movement of the battery module walking component, vibration component, and detection component is achieved by a speed-adjustable screw. At the same time, the ultrasonic vibration time is very short, which greatly improves the efficiency and does not cause operator fatigue.

[0022] (2) The battery module to be tested is directly placed on the installation table of the battery module walking component, and then the vibration can be directly simulated through the program setting of the vibration component and the detection component, and then the welding quality of the weld can be judged. There is no need to place the battery module to be tested on the vibration table to experience the vibration process, which reduces the process and thus ensures the production rhythm of the module. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the soft-pack battery module tab welding quality detection system of the present invention;

[0024] Figure 2 It is a side view of the soft-pack battery module tab welding quality detection system of the present invention;

[0025] Figure 3 This is a side view of the entire detection system when the upper plate is rotating;

[0026] In the figure: 1 host computer; 2 vibration leveling assembly, 21 ultrasonic welding machine, 2101 ultrasonic welding machine welding head, 22 second servo motor, 23 second screw slider pair, 24 second mounting platform, 25 second guide rail; 3 detection assembly, 31 line laser measuring instrument sensor head, 32 third servo motor, 33 third screw slider pair, 34 third mounting platform, 35 third guide rail; 4 battery module walking assembly, 41 first servo motor, 42 first screw slider pair, 43 first mounting platform, 4301 upper plate, 4302 lower plate, 44 first guide rail, 45 lifting plate; 5 barcode scanner; 6 machine. DETAILED DESCRIPTION

[0027] The preferred embodiments of the present invention are described in detail below. The technical features of each embodiment of the present invention can be combined accordingly without conflict.

[0028] A soft pack battery module tab welding quality detection system, such as Figure 1-2 As shown, the apparatus comprises a platform 6, a battery module travel assembly 4, a vibrating assembly 2, a detection assembly 3, a barcode scanner 5, and a host computer 1. The battery module travel assembly 4, vibrating assembly 2, detection assembly 3, and barcode scanner 5 are all connected to the host computer. The first guide rail 44 is disposed on the platform, and the vibrating assembly 2 and detection assembly 3 are mounted on the same side of the first guide rail 44. The ultrasonic welding machine welding head 2101 in the vibrating assembly 2 and the line laser measuring instrument sensor head 31 in the detection assembly 3 are both located above the first guide rail 44, with the line laser measuring instrument sensor head 31 located downstream of the ultrasonic welding machine welding head 2101.

[0029] The battery module walking assembly 4 includes a first servo motor 41, a first screw slider pair 42, a first mounting platform 43, and a first guide rail 44; the first screw slider pair 42 is installed on the first guide rail 44, the first mounting platform 43 is installed on the first screw slider pair 42, and the battery module under test is fixed on the first mounting platform 43; the first servo motor 41 is connected to the first screw slider pair 42.

[0030] The vibrating assembly 2 includes an ultrasonic welding machine 21, a second servo motor 22, a second screw slider pair 23, a second mounting platform 24, and a second guide rail 25; the second guide rail 25 is installed on the machine platform 6 and is perpendicular to the first guide rail 44; the second screw slider pair 23 is installed on the second guide rail 25, the second mounting platform 24 is installed on the second screw slider pair 23, and the ultrasonic welding machine 21 is fixed on the second mounting platform 24; the second servo motor 22 is connected to the second screw slider pair 23.

[0031] The detection component 3 includes a line laser measuring instrument, a third servo motor 32, a third screw slider pair 33, a third mounting platform 34, and a third guide rail 35; the third guide rail 35 is installed on the machine platform 6 and is perpendicular to the first guide rail 44; the third screw slider pair 33 is installed on the third guide rail 35, and the third mounting platform 34 is installed on the third screw slider pair 33; the line laser measuring instrument includes a line laser measuring instrument sensor head and a line laser measuring instrument controller, the line laser measuring instrument sensor head 31 is fixed on the third mounting platform 34, and the installation position of the line laser measuring instrument controller is not limited, and can be directly installed on the machine platform or on the third mounting platform; the third servo motor 32 is connected to the third screw slider pair 33.

[0032] In a specific embodiment of the present invention, the first mounting platform 43 of the battery module walking assembly 4 includes an upper plate 4301 and a lower plate 4302. The lower plate 4302 is fixed to the first screw slider pair 42, and the upper plate 4301 is mounted on the lower plate 4302, and the upper plate 4301 is capable of rotating. A lifting plate 45 is installed on the machine 6. When the first mounting platform 43 runs above the lifting plate 45, the lifting plate 45 can pass through the lower plate 4302 of the first mounting platform 43 and drive the upper plate 4301 of the first mounting platform 43 to rise and fall and rotate. The structural diagram of the entire system when the upper plate 4301 rotates is shown as follows: Figure 3 shown.

[0033] The total dimensions of the machine used in this embodiment are L*W*H: 1800mm*1700mm*1200mm. The rated power of the ultrasonic welding machine is 3000W, 20Khz, and the welding head is made of mold steel. The ultrasonic welding machine is fixed on the second mounting platform, and the second mounting platform can adjust the position in the y-axis direction under the drive of the second servo motor and the second lead screw slider pair. The power of the second servo motor is 0.3Kw. The welding head of the ultrasonic welding machine is different from the welding head of general ultrasonic welding. The contact part of the welding head busbar of the present invention should be made into a smooth and flat shape, with a narrow vertical surface (10mm), preferably a rectangle (it can be replaced according to different busbar sizes and shapes).

[0034] This example uses a KEYENCE line laser measuring instrument with an LJ-X8080 sensor head. Its measuring range is 73 ± 20.5 mm on the Z axis and 35.0 mm on the X axis. Its linearity is ±0.03% F.S. on the Z axis. The controller is LJ-X8000. The instrument is mounted on a third mounting platform, which is driven by a third servo motor and a third lead screw slider pair to adjust the position in the Y-axis. The third servo motor has a power of 0.3 kW.

[0035] The battery module to be tested is fixed on a first mounting platform, which can move in the x-axis direction driven by a first servo motor and a first lead screw slider pair. The power of the first servo motor is 1.5Kw.

[0036] In a specific implementation of the present invention, the output shafts of the three servo motors 22, 32, and 41 are connected to a driving sprocket or a driving pulley, and one end of the screw in the three screw slider pairs 23, 33, and 42 is connected to a driven sprocket or a driven pulley, and the driving sprocket and the driven sprocket are driven by a chain, or the driving pulley or the driven pulley is driven by a belt.

[0037] The above-mentioned soft-pack battery module tab welding quality inspection system is used to inspect the busbar on the battery module. The specific steps are as follows:

[0038] Step 1: Use the host computer to set the weld position, the qualified standards for the height difference between the tab and the busbar, and set the QR code rules used by different modules.

[0039] Step 2: Fix the battery module with the tabs already laser welded on the first mounting platform 43 of the battery module traveling assembly 4 .

[0040] Step 3: Set the vibration position of the ultrasonic welding machine welding head 2101 during operation (i.e., on the busbar near the weld position) through the host computer, the trigger time is 1.5s, the vibration time is 0.6s, the delay protection time is 1s, the trigger time is 2.5s, and the welding head drop cylinder pressure is 0.25Mpa. Adjust the speed and direction of the first servo motor, the second servo motor, and the third servo motor, and drive the first screw slider pair to work through the first servo motor to control the travel speed of the measured battery module on the first mounting table to 10mm / s, and the ultrasonic generator no-load sound wave amplitude is set to 1.6A; drive the second screw slider pair through the second servo motor to work, and adjust the ultrasonic welding machine welding head on the second mounting table to be located directly above the busbar on the side close to the vibrating assembly; drive the third screw slider pair through the third servo motor to work, and adjust the line laser measuring instrument sensor head on the third mounting table to be located directly above the busbar on the side close to the detection assembly.

[0041] Step 4: Start the system and scan the QR code of the battery module under test. When the battery module under test on the battery module walking assembly installation platform moves to the preset vibration position, the weld on the side close to the ultrasonic welding machine is located below the ultrasonic welding machine welding head. The welding head automatically drops according to the preset falling pressure and vibrates the designated position of the busbar near the weld. When the preset vibration time is reached, the vibration stops, and the welding head continues to press. The weld area is photographed and scanned by the line laser measuring instrument sensor head. The weld position is obtained by taking pictures, and the height difference between the tab and the busbar is measured and sent to the host computer for comparison with the standard weld position and height difference. When the difference between the test value and the standard value is within the preset range, the test is qualified. Otherwise, the test fails and the unqualified weld position is recorded. The welding head rises and the battery module under test continues to move. The vibration and measurement process is repeated until all the single-sided busbar weld positions on the battery module under test are vibrated and measured.

[0042] Step 5. Drive the second screw slider pair by the second servo motor to adjust the ultrasonic welding machine welding head on the second mounting platform to be directly above the bus on the side away from the vibrating assembly; drive the third screw slider pair by the third servo motor to adjust the line laser measuring instrument sensing head on the third mounting platform to be directly above the bus on the side away from the detection assembly; drive the first screw slider pair by the first servo motor to control the battery module under test on the first mounting platform to move in the opposite direction to the starting end, and then repeat the above step 4 to vibrate and measure all the bus weld positions on the other side of the battery module under test.

[0043] If the width of the battery module under test is greater than the stroke of the ultrasonic welding machine welding head and / or the line laser measuring instrument sensing head, move the first mounting platform to the top of the lifting plate, lift the lifting plate on the machine platform, and the lifting plate passes through the lower plate of the first mounting platform and drives the upper plate of the first mounting platform to rise and rotate. The battery module under test rotates 180 degrees with the upper plate, and the upper plate falls and is fixed on the lower plate. Then, the battery module under test on the first mounting platform is controlled to move in the opposite direction to the starting end, and the above step four is repeated to vibrate and measure all the busbar weld positions on the other side of the battery module under test.

[0044] Lift the lifting plate on the machine, which passes through the lower plate of the first mounting platform and drives the upper plate of the first mounting platform to rise and rotate. The battery module under test rotates 180 degrees with the upper plate. The upper plate falls and is fixed on the lower plate. Then, the battery module under test on the first mounting platform is controlled to move in the opposite direction to the starting end. Repeat step 3) to vibrate and measure all the busbar weld positions on the other side of the battery module under test.

[0045] Step 6: Based on the data recorded by the host computer, the previous process will re-laser weld the weld positions that failed the inspection.

[0046] The above examples are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above examples, and many variations are possible. All variations that can be directly derived or imagined by a person skilled in the art from the disclosure of the present invention should be considered to be within the scope of protection of the present invention.

Claims

1. A soft-pack battery module tab welding quality detection system, characterized in that: It includes a machine (6), a battery module walking component (4), a vibration leveling component (2), a detection component (3), a barcode scanning gun (5) and a host computer (1); The machine (6) is provided with a first guide rail (44), the battery module walking assembly (4) is installed on the first guide rail (44), the leveling assembly (2) and the detection assembly (3) are installed on the same side of the first guide rail (44), the ultrasonic welding machine welding head (2101) in the leveling assembly (2) and the line laser measuring instrument sensing head (31) in the detection assembly (3) are located above the first guide rail (44), and the line laser measuring instrument sensing head (31) is set at a process downstream position of the ultrasonic welding machine welding head (2101); the battery module walking assembly (4), the leveling assembly (2), the detection assembly (3), and the barcode scanning gun (5) are all connected to the host computer (1); The battery module travel assembly (4) includes a first servo motor (41), a first screw slider pair (42), and a first mounting platform (43) fixed to the first screw slider pair (42), the first screw slider pair (42) is mounted on a first guide rail (44), and the first servo motor (41) is connected to the first screw slider pair (42); The vibration leveling assembly (2) includes an ultrasonic welding machine (21), a second servo motor (22), a second lead screw slider pair (23), and a second mounting platform (24) fixed on the second lead screw slider pair (23); the ultrasonic welding machine (21) is fixed on the second mounting platform (24); the second lead screw slider pair (23) is installed on a second guide rail (25) on the machine platform (6), and the second servo motor (22) is connected to the second lead screw slider pair (23); the second guide rail (25) is perpendicular to the first guide rail (44); the working surface of the ultrasonic welding machine welding head (2101) is a plane, and the ultrasonic welding machine welding head is used to transmit vibration energy to the battery module to be tested, and vibrate the specified position of the busbar near the weld; The detection assembly (3) includes a line laser measuring instrument sensor head (31), a third servo motor (32), a third lead screw slider pair (33), and a third mounting platform (34) fixed on the third lead screw slider pair (33); the line laser measuring instrument sensor head (31) is fixed on the third mounting platform (34); the third lead screw slider pair (33) is mounted on a third guide rail (35) on the machine platform (6), and the third servo motor (32) is connected to the third lead screw slider pair (33); the third guide rail (35) is perpendicular to the first guide rail (44).

2. The soft-pack battery module tab welding quality detection system according to claim 1, characterized in that: The first mounting platform (43) of the battery module walking assembly (4) comprises an upper plate (4301) and a lower plate (4302), wherein the lower plate (4302) is fixed on the first screw slider pair (42), and the upper plate (4301) is mounted on the lower plate (4302), and the upper plate is rotatable.

3. The soft-pack battery module tab welding quality detection system according to claim 2, characterized in that: A lifting plate (45) is installed on the machine (6). When the first mounting platform (43) moves above the lifting plate (45), the lifting plate (45) can pass through the lower plate (4302) of the first mounting platform (43) and drive the upper plate (4301) of the first mounting platform (43) to rise, fall and rotate.

4. A detection method for the soft-pack battery module tab welding quality detection system according to any one of claims 1 to 3, characterized in that: The steps include: 1) Fixing the battery module to be tested on the first mounting platform (43) of the battery module traveling assembly (4), wherein the tabs and busbars on the battery module to be tested have been welded; 2) setting the vibration position, vibration time and falling pressure of the ultrasonic welding machine welding head (2101) during operation through the upper computer (1); adjusting the rotation speed and direction of the first servo motor (41), the second servo motor (22) and the third servo motor (32); driving the first screw slider pair (42) to work through the first servo motor (41) to control the travel speed of the battery module under test on the first mounting platform (43); driving the second screw slider pair (23) to work through the second servo motor (22) to adjust the ultrasonic welding machine welding head (2101) on the second mounting platform (24) to be located above the busbar on the side close to the vibration leveling component (2); driving the third screw slider pair (33) to work through the third servo motor (32) to adjust the line laser measuring instrument sensor head (31) on the third mounting platform (34) to be located directly above the busbar on the side close to the detection component (3); 3) starting the system, when the battery module under test on the first mounting platform (43) of the battery module walking assembly (4) moves to a preset vibration position, the weld on the side close to the ultrasonic welding machine (21) is located below the ultrasonic welding machine welding head (2101), and the welding head automatically falls according to the preset falling pressure and vibrates the designated position of the bus near the weld; when the preset vibration time is reached, the ultrasonic welding machine welding head (2101) presses the bus, and the line laser measuring instrument sensing head (31) takes a photo and scans the weld area, and measures the height difference between the tab and the bus and sends it to the host computer (1); the ultrasonic welding machine welding head (2101) rises, and the battery module under test continues to move, repeating the vibration and measurement process until all the single-side bus weld positions on the battery module under test are vibrated and measured; 4) The second servo motor (22) drives the second lead screw slider pair (23) to work, and adjusts the ultrasonic welding machine welding head (2101) on the second mounting platform (24) to be located above the busbar on the side away from the vibrating assembly (2); the third servo motor (32) drives the third lead screw slider pair (33) to work, and adjusts the line laser measuring instrument sensor head (31) on the third mounting platform (34) to be located directly above the busbar on the side away from the detection assembly (3); the first servo motor (41) drives the first lead screw slider pair (42) to work, and controls the battery module to be tested on the first mounting platform (43) to move in the reverse direction to the starting end, and then repeats the above step 3) to vibrate and measure all the busbar weld positions on the other side of the battery module to be tested.

5. The detection method of the soft-pack battery module tab welding quality detection system according to claim 4, characterized in that: When the width of the battery module to be tested is greater than the stroke of the ultrasonic welding machine welding head and / or the line laser measuring instrument sensing head, the lifting plate (45) on the machine is raised, the lifting plate (45) passes through the lower plate (4302) of the first mounting platform (43) and drives the upper plate (4301) of the first mounting platform (43) to rise and rotate, the battery module to be tested rotates 180 degrees with the upper plate, the upper plate (4301) falls and is fixed on the lower plate (4302), and then the battery module to be tested on the first mounting platform (43) is controlled to move in the opposite direction to the starting end, and the above step 3 is repeated, and all the busbar weld positions on the other side of the battery module to be tested are vibrated and measured.

6. The detection method of the soft-pack battery module tab welding quality detection system according to claim 4, characterized in that: The traveling speed of the battery module under test is 10 mm / s.

7. The detection method of the soft-pack battery module tab welding quality detection system according to claim 4, characterized in that: The vibration time of the ultrasonic welding machine welding head (2101) is 0.6 s and the falling pressure is 0.25 MPa.

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