Laser welding tool for cylindrical lithium battery

Abstract

The invention relates to the technical field of battery production and manufacturing, and discloses a cylindrical lithium battery laser welding tool which comprises a welding frame, a telescopic arm is slidably mounted on the outer side of the welding frame, a pressing plate is fixedly mounted at the bottom of the telescopic arm, and the cylindrical lithium battery laser welding tool further comprises a load resistor movably mounted at the bottom of the pressing plate; the two ends of the load resistor are fixedly provided with wires, and the ends, away from the load resistor, of the two wires are fixedly provided with feeler levers. According to the invention, the internal resistance value of the cell panel is detected through the series load resistor so as to judge whether the welding point is subjected to pseudo soldering, so that the detection requirement is met, whether the welding point is subjected to pseudo soldering can be more accurately judged, a CCD camera does not need to continuously shoot for a long time, and the CCD camera is prevented from influencing the image quality and causing detection errors due to long-time continuous shooting. The service life of the CCD camera is prolonged, and the stability and reliability of the whole lithium battery assembly process are improved.

Description

Technical Field

[0001] This application relates to the technical field of battery production and manufacturing, and particularly to a laser welding tooling for cylindrical lithium batteries. Background Art

[0002] In the core links of the industrial production and precision assembly of lithium battery packs, operators need to follow strict technical specifications to electrically connect multiple single battery plates in series or parallel through high-precision battery connection pieces. During this process, defects in a single solder joint may cause safety hazards such as imbalance in the internal resistance of the battery pack, local overheating, and even thermal runaway. To ensure that the welding quality meets the standards, CCD (Charge Coupled Device) industrial cameras based on machine vision are generally used for solder joint detection on the production line. This system captures key parameters such as the morphology of the solder joint molten pool, weld width, and surface finish through a high-resolution lens, and automatically compares them with preset standards using image processing algorithms to accurately identify defects such as false soldering, missed soldering, and solder splash.

[0003] However, when the CCD camera is in the long-term continuous shooting mode, the CMOS sensor inside it will generate a thermal accumulation effect due to continuous exposure to light, resulting in a significant increase in dark current noise, which directly weakens the dynamic range and signal-to-noise ratio of the image. At the same time, high-frequency exposure will cause fatigue deformation of the mechanical shutter or electronic shutter system, leading to mechanical failures such as focus drift or shutter jamming. The continuously operating high-power LED ring light source will also generate thermal radiation interference, forming a thermal halo effect on the lens surface, causing image edge blurring and color temperature drift. When these factors are combined, they will not only shorten the service life of key components of the camera (such as image sensors and cooling fans), but also may lead to an increase in the misjudgment rate of the detection system: solder joints that originally meet the standards may be mislabeled as false soldering, resulting in unnecessary rework or waste, while solder joints with hidden defects may be missed due to image distortion, affecting production quality and ultimately the quality certification and safety performance of the entire battery pack. Summary of the Invention

[0004] This application proposes a laser welding tooling for cylindrical lithium batteries, which has the advantages of accurately judging whether there is false soldering in the solder joint, avoiding the influence of long-term continuous shooting of the CCD camera on the image quality and resulting in detection errors, extending the service life of the CCD camera, and improving the stability and reliability of the entire lithium battery assembly process, so as to solve the problem that the misjudgment rate of the detection system increases due to long-term continuous shooting of the CCD camera during the production of lithium battery packs, affecting quality certification and safety performance.

[0005] To achieve the above object, the present application adopts the following technical solution: A laser welding tooling for cylindrical lithium batteries, including a welding frame, a telescopic arm is slidably installed on the outside of the welding frame, a pressing plate is fixedly installed at the bottom of the telescopic arm, and a load resistor movably installed at the bottom of the pressing plate is further included. Both ends of the load resistor are fixedly installed with wires, and a contact rod is fixedly installed at one end of each of the two wires away from the load resistor. After the contact rod moves down with the pressing plate, it contacts the battery connection piece, forming a series circuit with the load resistor and the battery plate that has completed welding. A device for detecting the voltages at both ends of the load resistor and the battery plate is provided on the series circuit, and the calculated internal resistance of the battery plate is fed back to the control system to determine whether the internal resistance of the battery plate is abnormal. If it is abnormal, the CCD camera is started to detect the quality of the solder joint.

[0006] Further, a connecting plate is fixedly installed on one side of the pressing plate, and the length of the connecting plate is the same as the distance between two battery connection pieces on the battery plate, which is used to provide support and protection for one of the wires.

[0007] Further, mounting posts are fixedly installed on the inner side wall of the welding hole on the pressing plate. Installation grooves are opened at the bottoms of the connecting plate and the mounting posts. A limiting plate is slidably installed inside the installation groove. A tension spring is fixedly installed at the bottom of the limiting plate, and both the limiting plate and the tension spring are sleeved on the outside of the contact rod. The top end of the tension spring is fixedly connected to the inner bottom wall of the installation groove, which is used to ensure the stable fit between the contact rod and the battery connection piece.

[0008] Further, a movable groove is opened at the bottom of the pressing plate. A connecting column is movably installed inside the movable groove. A rotating rod is fixedly installed at the end of the two connecting columns away from the telescopic arm. A torsion spring is sleeved on the outside of the rotating rod. Fixing rings are fixedly installed at the ends of the two connecting columns close to the telescopic arm. A pressing column is fixedly installed between the two fixing rings, and the load resistor is placed inside the pressing column.

[0009] Further, two sliding columns are symmetrically and fixedly installed at the top of the end of the pressing plate away from the telescopic arm. A sliding rod is slidably installed at the bottom of the sliding column. A spring is fixedly installed between the top end of the sliding rod and the inner top wall of the sliding column. The bottom end of the sliding rod movably penetrates through the pressing plate and is fixedly installed with a stabilizing plate. A limiting groove adapted to the stabilizing plate is opened at the top of the pressing plate, which is used to provide an installation space for the stabilizing plate.

[0010] The beneficial effects of the present invention are as follows:

[0011] A laser welding tooling for cylindrical lithium batteries provided by the present application, when welding battery connection pieces, drives a contact rod to move downward through a pressing plate. The contact rod touches the battery connection pieces at both ends of the battery plate, and then connects a load resistor in series with the welded battery plate. By measuring the voltage division of the load resistor and the electromotive force of the battery plate through relevant instruments, combined with the known resistance value of the load resistor, the internal resistance value of the battery plate is deduced and compared with the standard value, so as to judge whether there is a false soldering. Detecting the internal resistance value of the battery plate by connecting a load resistor in series to judge whether the solder joint is falsely soldered not only meets the detection requirements, can more accurately judge whether there is a false soldering at the welding point, but also does not require the CCD camera to continuously shoot for a long time, avoiding the CCD camera from affecting the image quality due to continuous shooting for a long time, resulting in detection errors, prolonging the service life of the CCD camera, and improving the stability and reliability of the entire lithium battery assembly process. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings:

[0013] Figure 1 is a three-dimensional structural schematic diagram of the present invention;

[0014] Figure 2 is a bottom view structural schematic diagram of the welding frame and the pressing plate of the present invention;

[0015] Figure 3 is a structural schematic diagram of the wire, the rotating rod and the pressing column of the present invention;

[0016] Figure 4 is a partial side view sectional structural schematic diagram of the connecting plate of the present invention;

[0017] Figure 5 is a structural schematic diagram of the telescopic arm, the pressing plate and the sliding column of the present invention.

[0018] In the figure: 1. Welding frame; 2. Telescopic arm; 3. Pressing plate; 4. Connecting plate; 5. Wire; 6. Contact rod; 7. Mounting column; 8. Mounting groove; 9. Limiting plate; 10. Tension spring; 11. Moving groove; 12. Connecting column; 13. Rotating rod; 14. Torsion spring; 15. Fixed ring; 16. Pressing column; 17. Sliding column; 18. Sliding rod; 19. Stabilizing plate; 20. Limiting groove. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] Refer to Figures 1 to 5 , a laser welding tooling for cylindrical lithium batteries, including a welding frame 1. A telescopic arm 2 is slidably installed on the outside of the welding frame 1. A pressing plate 3 is fixedly installed at the bottom of the telescopic arm 2. During welding, the control system operates the telescopic arm 2 to drive the pressing plate 3 to move downwards. The pressing plate 3 first presses on the surface of the battery connection piece to limit it, and then the laser welding device emits a laser beam to weld the welding point. A load resistor is movably installed at the bottom of the pressing plate 3. Wires 5 are fixedly installed at both ends of the load resistor. Touch rods 6 are fixedly installed at the ends of the two wires 5 far away from the load resistor. A connecting plate 4 is fixedly installed on one side of the pressing plate 3, and the length of the connecting plate 4 is the same as the distance between the positive and negative electrodes on the same battery plate, which is used to electrically connect the positive and negative electrodes of the same battery plate and provide support and protection for one of the wires 5. An installation column 7 is fixedly installed on the inner side wall of the welding hole on the pressing plate 3. Installation grooves 8 are opened at the bottoms of the connecting plate 4 and the installation column 7. A limiting plate 9 is slidably installed inside the installation groove 8. A tension spring 10 is fixedly installed at the bottom of the limiting plate 9, and both the limiting plate 9 and the tension spring 10 are sleeved outside the touch rod 6. The top of the tension spring 10 is fixedly connected to the inner bottom wall of the installation groove 8. Under the action of the tension spring 10, the limiting plate 9 is pulled towards the inner bottom wall of the installation groove 8, and the bottom end of the touch rod 6 is also outside the installation groove 8. When welding the battery connection piece, after completing the welding on one side, the integrated system controls the movement of the welding frame 1, the telescopic arm 2, the pressing plate 3, etc. to the other side (to Figure 1For example, during welding, first weld the battery connection piece on the surface of the battery panel at the end far from the pressing plate 3, which is the side to be welded first. At this time, the connecting plate 4 is in a suspended state, so it will not affect the stability of the battery connection piece. After welding, move to the battery connection piece near the pressing plate 3. As the pressing plate 3 moves down, the contact rod 6 also contacts the battery connection piece. When the bottom wall of the pressing plate 3 fits with the battery connection piece, the contact rod 6 is also squeezed and slides into the installation groove 8, and the tension spring 10 is stretched. However, under the action of the pulling force of the tension spring 10, during the process of the pressing plate 3 gradually moving up after welding is completed, the contact rod 6 can still contact the surface of the battery connection piece, thereby connecting the load resistor in series with the welded battery panel, and the voltage division of the load resistor and the electromotive force of the battery panel are measured by relevant instruments. Combining the known resistance value of the load resistor, the internal resistance value of the battery panel is deduced. If it is higher than the internal resistance value when normal welding without false soldering occurs, it indicates that there may be a situation of false soldering at the solder joints on this battery panel. At this time, use a CCD camera to take a photo for verification. If it is confirmed as false soldering, then carry out relevant repair treatment. Detecting the internal resistance value of the battery panel by connecting the load resistor in series to judge whether there is false soldering not only meets the detection requirements, but also does not require the CCD camera to continuously shoot for a long time, reducing the hardware loss and overheating problems brought by continuous high-frequency shooting of the CCD camera, and significantly extending the service life of the CCD camera.

[0021] An activity groove 11 is opened at the bottom of the pressing plate 3. A connecting column 12 is movably installed inside the activity groove 11. The two connecting columns 12 are fixedly installed with a rotating rod 13 at the ends far from the telescopic arm 2. A torsion spring 14 is sleeved outside the rotating rod 13. The two connecting columns 12 are fixedly installed with fixing rings 15 at the ends close to the telescopic arm 2. A pressing column 16 is fixedly installed between the two fixing rings 15, and the load resistor is placed inside the pressing column 16. The wires 5 at both ends of the load resistor are respectively installed inside the corresponding connecting column 12 and then into the inside of the rotating rod 13, and then movably penetrate through the rotating rod 13 and are respectively installed inside the installation column 7 or the connecting plate 4. Thus, when the load resistor rotates with the pressing column 16, the relevant wires 5 will not affect the welding process due to telescopic movement. Under the action of the torsion spring 14, when the pressing plate 3 moves down, the inclined connecting column 12 makes the pressing column 16 contact the surface of the battery connection piece first. As the pressing plate 3 continues to move down, the connecting column 12 and the pressing column 16 rotate around the rotating rod 13, and the pressing column 16 slides on the surface of the battery connection piece until the connecting column 12 and the pressing column 16 are pressed into the activity groove 11. By pressing the battery connection piece with the pressing column 16, the probability of a gap appearing between the battery connection piece and the battery panel is further reduced, and thus the probability of false soldering at the solder joints is reduced, improving the welding quality.

[0022] At the top of one end of the pressing plate 3 away from the telescopic arm 2, two sliding columns 17 are symmetrically and fixedly installed. A sliding rod 18 is slidably installed at the bottom of the sliding column 17. A spring is fixedly installed between the top end of the sliding rod 18 and the inner top wall of the sliding column 17. The bottom end of the sliding rod 18 movably penetrates through the pressing plate 3 and is fixedly installed with a stabilizing plate 19. A limiting groove 20 adapted to the stabilizing plate 19 is formed at the top of the pressing plate 3. When the pressing plate 3 does not move downward, the elastic force of the spring causes the stabilizing plate 19 to be below the pressing column 16. When the pressing plate 3 moves downward, the stabilizing plate 19 first fits with the battery connecting piece to limit the battery connecting piece, preventing the pressing column 16 from sliding on the surface of the battery connecting piece and causing it to shift. As the pressing plate 3 continues to move downward, the spring is compressed, and the sliding rod 18 gradually slides upward. Finally, the stabilizing plate 19 is pressed into the limiting groove 20 without affecting the normal pressing and limiting of the pressing plate 3.

[0023] Working principle:

[0024] During welding, the control system operates the telescopic arm 2 to drive the pressing plate 3 to move downward. The pressing plate 3 first presses on the surface of the battery connecting piece to limit it, and then the laser welding device emits a laser beam to weld the welding point. When the pressing plate 3 moves downward, the stabilizing plate 19 first fits with the battery connecting piece to limit the battery connecting piece, and then the pressing column 16 contacts the surface of the battery connecting piece. As the pressing plate 3 continues to move downward, the pressing column 16 slides on the surface of the battery connecting piece until the connecting column 12 and the pressing column 16 are pressed into the inner part of the moving groove 11. By pressing the battery connecting piece with the pressing column 16, the probability of a gap appearing between the battery connecting piece and the battery plate is further reduced;

[0025] When welding the first side, the connecting plate 4 is placed outside the battery panel and is in a suspended state to prevent it from touching the un-welded battery connection piece and causing its deviation. After completing the welding of one side, the integrated system controls the movement of the welding frame 1, the telescopic arm 2, the pressing plate 3, etc. to the other side. As the pressing plate 3 moves downward, the contact rod 6 also contacts the battery connection piece. When the bottom wall of the pressing plate 3 fits with the battery connection piece, the contact rod 6 is also squeezed and slides into the interior of the installation groove 8, and the tension spring 10 is stretched. However, under the action of the elastic force of the tension spring 10, during the process of the pressing plate 3 gradually moving upward after welding is completed, the contact rod 6 can still contact the surface of the battery connection piece, thereby connecting the load resistor in series with the completed-welding battery panel, and the voltage division of the load resistor and the electromotive force of the battery panel are measured by relevant instruments. Combining with the known resistance value of the load resistor, the internal resistance value of the battery panel is deduced. If it is higher than the internal resistance value when normal welding has no false welding, it indicates that there may be a false welding situation at the solder joints on this battery panel. At this time, the CCD camera is used to take pictures and verify it. If it is confirmed as false welding, relevant repair treatment is carried out. By detecting the internal resistance value of the battery panel by connecting the load resistor in series to judge whether there is false welding at the solder joints, not only the detection requirements are completed, and it can more accurately judge whether there is false welding at the welding points, but also there is no need for the CCD camera to continuously take pictures for a long time, avoiding the CCD camera affecting the image quality due to continuous shooting for a long time, resulting in detection errors, prolonging the service life of the CCD camera, and improving the stability and reliability of the entire lithium battery assembly process.

[0026] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A laser welding tooling for cylindrical lithium batteries, comprising a welding frame (1), wherein a telescopic arm (2) is slidably mounted on the outer side of the welding frame (1), and a pressing plate (3) is fixedly mounted at the bottom of the telescopic arm (2), characterized in that, It also includes a load resistor movably mounted on the pressing plate (3). Wires (5) are fixedly mounted at both ends of the load resistor. Contact rods (6) are fixedly mounted at the ends of the two wires (5) away from the load resistor. After the contact rods (6) move down with the pressing plate (3), they come into contact with the battery connection piece, forming a series circuit with the load resistor and the battery panel that has been welded. A voltage detector is provided on the series circuit to detect the voltages at both ends of the load resistor and the battery panel, and the internal resistance of the battery panel calculated based on the known load resistor is fed back to the control system to determine whether the internal resistance of the battery panel is abnormal.

2. The cylindrical lithium battery laser welding tooling according to claim 1, wherein One side of the pressing plate (3) is fixedly mounted with a connecting plate (4), and the length of the connecting plate (4) is the same as the distance between the positive and negative electrodes on the same battery panel, for electrically connecting the positive and negative electrodes of the same battery panel.

3. A cylindrical lithium battery laser welding tooling according to claim 2, characterized in that, Mounting posts (7) are fixedly mounted on the inner side walls of the welding holes on the pressing plate (3). Mounting grooves (8) are formed at the bottoms of the connecting plate (4) and the mounting posts (7). Limiting plates (9) are slidably mounted inside the mounting grooves (8). A tension spring (10) is fixedly mounted at the bottom of the limiting plate (9), and both the limiting plate (9) and the tension spring (10) are sleeved outside the contact rod (6). The top end of the tension spring (10) is fixedly connected to the inner bottom wall of the mounting groove (8), for ensuring stable fitting between the contact rod (6) and the battery connection piece.

4. A cylindrical lithium battery laser welding tooling according to claim 3, characterized in that, An activity groove (11) is formed at the bottom of the pressing plate (3). A connecting column (12) is movably mounted inside the activity groove (11). A rotating rod (13) is fixedly mounted at the ends of the two connecting columns (12) away from the telescopic arm (2). A torsion spring (14) is sleeved outside the rotating rod (13). Fixed rings (15) are fixedly mounted at the ends of the two connecting columns (12) close to the telescopic arm (2). A pressing column (16) is fixedly mounted between the two fixed rings (15), and the load resistor is placed inside the pressing column (16).

5. A cylindrical lithium battery laser welding tooling according to claim 4, characterized in that, Two sliding columns (17) are symmetrically and fixedly mounted at the top of the end of the pressing plate (3) away from the telescopic arm (2). A sliding rod (18) is slidably mounted at the bottom of the sliding column (17). A spring is fixedly mounted between the top end of the sliding rod (18) and the inner top wall of the sliding column (17). The bottom end of the sliding rod (18) movably penetrates through the pressing plate (3) and is fixedly mounted with a stabilizing plate (19). A limiting groove (20) adapted to the stabilizing plate (19) is formed at the top of the pressing plate (3), for providing a placement space for the stabilizing plate (19).

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