Testing device and testing method for square battery module

Abstract

The invention discloses a testing device and method for a square battery module in the technical field of battery modules, and the device comprises an outer frame, the bottom of the outer frame is fixedly connected with a pedestal, the top end of the outer frame is fixedly connected with a hydraulic rod, the output end of the hydraulic rod is provided with a puncture rod, one side of the outer frame is fixedly connected with a control console, and the control console is fixedly connected with the pedestal. A neutralization cleaning assembly is arranged in the outer frame, the neutralization cleaning assembly is adopted, a puncture experiment on a battery and cleaning of a puncture rod after puncture are carried out at the same time, it is not needed to independently clean the puncture rod after puncture is completed, and then the puncture experiment is carried out, so that the efficiency of the puncture experiment can be effectively improved; by rotating the puncture rod to be in contact with the friction cylinder, impurities attached to the surface of the puncture rod can be cleaned up, chemical battery liquid attached to the surface of the puncture rod due to puncture of the battery module is flushed away, and the situation that the battery liquid on the surface of the puncture rod influences the puncture experiment in the subsequent puncture experiment is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of battery modules, and in particular to a testing device and a testing method for a square battery module. Background Art

[0002] A prismatic battery module is a battery module that assembles multiple lithium batteries into a square shape. It is mostly used in pedal-powered electric vehicles and electric vehicles. According to the outer material, it is divided into: aluminum shell lithium battery, steel shell lithium-ion battery, and soft pack lithium battery; according to the positive electrode material, it is mainly divided into: lithium cobalt oxide, nickel cobalt manganese, nickel cobalt aluminum, lithium iron phosphate, lithium ferrous phosphate, lithium manganese oxide, and lithium polymer battery.

[0003] After the battery module is produced and processed, it needs to undergo various tests to ensure the battery quality, including destructive puncture tests. By puncturing the battery module, the battery's extrusion and explosion data is obtained to determine how much pressure the battery can withstand without exploding in the event of a collision. The existing puncture test generally involves inserting a puncture rod into the battery by squeezing. After the test is completed, the puncture rod is removed and the test is repeated. However, since the battery contains chemical components, they are very easy to adhere to the surface of the puncture rod. If the surface of the puncture rod is not cleaned, the accuracy of the subsequent puncture test may be affected. In addition, the chemical components attached to the surface of the puncture rod are easy to corrode the puncture rod. Cleaning the puncture rod after each puncture test will affect the efficiency of the puncture test.

[0004] Based on this, the present invention designs a testing device and method for square battery modules to solve the problem that the surface of the puncture rod may adhere to chemical components due to puncturing the battery and affect the puncture test. Summary of the Invention

[0005] The object of the present invention is to provide a testing device and a testing method for a prismatic battery module to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a testing device for a square battery module, comprising an outer frame, a base fixedly connected to the bottom of the outer frame, a hydraulic rod fixedly connected to the top of the outer frame, a puncture rod provided at the output end of the hydraulic rod, a console fixedly connected to one side of the outer frame, and a neutralization and cleaning component provided inside the outer frame, the neutralization and cleaning component being used to clean off the chemical components on the puncture rod after puncturing the battery.

[0007] As a further solution of the present invention, the neutralization and cleaning assembly includes a connecting plate, which is arranged inside the outer frame, and both sides of the bottom of the connecting plate are fixedly connected to the puncture rod, and both sides of the top of the connecting plate are fixedly connected to the docking rail rod, and the output shaft of the hydraulic rod is fixedly connected to the docking block for rotatably connecting to the docking rail rod, the top of the connecting plate is fixedly connected to the telescopic rod, and the top of the outer frame is fixedly connected to the sleeve, the output shaft of the telescopic rod is rotatably connected to the sleeve, the top of the outer frame is fixedly connected to the rotating motor, the output shaft of the rotating motor passes through the outer frame and is fixedly connected to the output shaft of the telescopic rod inside the sleeve, and the bottom of the outer frame is fixedly connected to the soaking cylinder, and the soaking cylinder is provided with a friction cylinder for docking with the puncture rod.

[0008] As a further solution of the present invention, the top end of the puncture rod is fixedly connected to a fixed gear, the side wall of the outer frame is fixedly connected to a slide plate, the slide plate is slidably connected to a screw rod, one end of the screw rod is spirally sleeved with a connecting rod, the outside of the connecting rod is slidably connected to a first rack rod, one end of the connecting rod is fixedly connected to a reset spring for resetting the first rack rod, the side wall of the slide plate is fixedly connected to a second rack rod, the screw rod is fixedly connected to a connecting gear for meshing with the second rack rod, and the two side walls of the connecting plate are respectively fixedly connected to a transmission sleeve.

[0009] As a further solution of the present invention, a fixing plate is fixedly connected to the top of the soaking cylinder, and a pushing cylinder is fixedly connected to both sides of the fixing plate. A fixed shaft is fixedly connected to the top of the fixing plate, and a clamping sleeve is slidably connected to the fixed shaft. The output end of the pushing cylinder is fixedly connected to the clamping sleeve.

[0010] As a further solution of the present invention, a foam block with strong water absorption is fixedly connected to the inner wall of the clamping sleeve.

[0011] As a further solution of the present invention, the side wall of the outer frame is fixedly connected to a fire extinguisher, the front and rear ends of the outer frame are respectively fixedly connected to nozzles, and the input ends of the two nozzles are respectively connected to the fire extinguisher.

[0012] As a further solution of the present invention, a fixed gear is slidably connected to the slide plate, and a docking ring for sliding connection with the fixed gear is provided on the first rack rod.

[0013] A method for testing a prismatic battery module, the method comprising the following steps: Step 1: Place the square battery module to be punctured on the base stably; Step 2: Use the hydraulic rod to drive the puncture rod downward to perform a puncture test on the battery module, and observe the corresponding experimental data through the console; Step 3: After the puncture is completed, the puncture rod is cleaned by the neutralization and cleaning component to remove the chemical components attached to the surface after puncturing the battery; Step 4: Replace the battery module with a new one and repeat the puncture test.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention adopts a neutralization and cleaning component, so that the battery puncture test and the post-puncture cleaning of the puncture rod are carried out simultaneously. It is not necessary to clean the puncture rod separately after the puncture is completed and then use it for the puncture test. This can effectively improve the efficiency of the puncture test. The puncture rod is rotated to contact the friction cylinder, so that impurities attached to the surface of the puncture rod can be cleaned, and the chemical battery liquid attached to the surface of the puncture rod due to puncturing the battery module can be rinsed clean, thereby avoiding the battery liquid on the surface of the puncture rod affecting the puncture test during subsequent puncture tests. At the same time, it can also avoid corrosion caused by the long-term attachment of the battery liquid to the puncture rod, effectively improving the service life of the puncture rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the front structure of the present invention; Figure 3 Schematic diagram of the telescopic rod, connecting plate and puncture rod structure; Figure 4 Schematic diagram of the structure of the first rack rod, the lead screw, the connecting gear and the second rack rod; Figure 5 Schematic diagram of the partial cross-section structure of the first rack rod; Figure 6 Schematic diagram of the soaking tube structure; Figure 7 Flow chart of the method of the present invention.

[0016] In the accompanying drawings, the components represented by the reference numerals are as follows: 1. Control console; 2. Rotating motor; 3. Outer frame; 4. Fire extinguisher; 5. Nozzle; 6. Base; 7. Hydraulic rod; 8. Sleeve; 9. Telescopic rod; 10. Connecting plate; 11. Piercing rod; 12. Soaking cylinder; 13. Docking block; 14. Docking rail rod; 15. First rack rod; 16. Transmission sleeve; 17. Fixed gear; 18. Connecting gear; 19. Second rack rod; 20. Slide plate; 21. Return spring; 22. Connecting rod; 23. Screw rod; 24. Fixed plate; 25. Foam block; 26. Clamping sleeve; 27. Fixed shaft; 28. Push cylinder; 29. ​​Friction cylinder; 30. Limit rod. DETAILED DESCRIPTION

[0017] See also Figure 1-7The present invention provides a technical solution: a testing device for a square battery module, comprising an outer frame 3, a base 6 fixedly connected to the bottom of the outer frame 3, a hydraulic rod 7 fixedly connected to the top of the outer frame 3, a puncture rod 11 provided at the output end of the hydraulic rod 7, a console 1 fixedly connected to one side of the outer frame 3, and a neutralization and cleaning component provided inside the outer frame 3, the neutralization and cleaning component being used to clean off the chemical components on the puncture rod 11 after puncturing the battery; When the above scheme is put into actual use, when conducting a puncture test, the square battery module to be punctured is placed stably on the base 6, and the puncture rod 11 is driven downward by the hydraulic rod 7 to perform a puncture test on the battery module. The corresponding experimental data is observed through the console 1. After the puncture is completed, the puncture rod 11 is cleaned by the neutralization and cleaning component to clean the chemical components attached to the surface after puncturing the battery, and then the puncture test on the battery module can be continued. The advantage of this is that after each puncture test, the puncture rod 11 can be cleaned to rinse the chemical battery liquid attached to the surface of the puncture rod 11 due to puncturing the battery module, thereby avoiding the battery liquid on the surface of the puncture rod 11 from affecting the puncture test during subsequent puncture tests. At the same time, it can also avoid the corrosion caused by the long-term adhesion of the battery liquid to the puncture rod 11, effectively improving the service life of the puncture rod 11.

[0018] As a further solution of the present invention, the neutralization and cleaning assembly includes a connecting plate 10, which is arranged inside the outer frame 3, and the two sides of the bottom of the connecting plate 10 are respectively fixedly connected to the puncture rod 11, and the two sides of the top of the connecting plate 10 are respectively fixedly connected to the docking rail rod 14, and the bottom output shaft of the hydraulic rod 7 is fixedly connected to a docking block 13 for rotatably connecting to the docking rail rod 14, the top of the connecting plate 10 is fixedly connected to the telescopic rod 9, the top of the outer frame 3 is fixedly connected to the sleeve 8, the output shaft of the telescopic rod 9 is rotatably connected to the sleeve 8, the top of the outer frame 3 is fixedly connected to the rotating motor 2, the output shaft of the rotating motor 2 passes through the outer frame 3 and is fixedly connected to the output shaft of the telescopic rod 9 inside the sleeve 8, the bottom of the outer frame 3 is fixedly connected to the soaking cylinder 12, and the soaking cylinder 12 is provided with a friction cylinder 29 for docking with the puncture rod 11, the top of the puncture rod 11 is fixedly connected to the fixed gear 17, the outer frame 3 The side wall is fixedly connected to a slide plate 20, and a screw rod 23 is slidably connected to the inside of the slide plate 20. One end of the screw rod 23 is spirally sleeved with a connecting rod 22, and the outside of the connecting rod 22 is slidably connected to the first rack rod 15, and one end of the connecting rod 22 is fixedly connected to a return spring 21 for returning the first rack rod 15 to the ground. The side wall of the slide plate 20 is fixedly connected to the second rack rod 19, and the screw rod 23 is fixedly connected to the connecting gear 18 for meshing with the second rack rod 19. The transmission sleeve 16 is fixedly connected to the two side walls of the connecting plate 10. The top of the soaking cylinder 12 is fixedly connected to a fixing piece 24, and both sides of the fixing piece 24 are fixedly connected to a pushing cylinder 28. The top of the fixing piece 24 is fixedly connected to a fixed shaft 27, and a clamping sleeve 26 is slidably connected to the fixed shaft 27. The output end of the pushing cylinder 28 is fixedly connected to the clamping sleeve 26. The inner wall of the clamping sleeve 26 is fixedly connected to a foam block 25 with strong water absorption; When the above scheme is put into actual use, when conducting a puncture test, the hydraulic rod 7 is started to push the connecting plate 10 down, so that the telescopic rod 9 is stretched, and the puncture rod 11 on the top of the base 6 directly punctures the battery for the test. After the experiment is completed, the hydraulic rod 7 drives the puncture rod 11 to reset, and then the rotating motor 2 is started to drive the telescopic rod 9 to rotate, and the telescopic rod 9 drives the connecting plate 10 to rotate, so that the connecting plate 10 rotates 180 degrees to swap the positions of the two puncture rods 11 at the bottom, and the rotation position is determined by rotating the docking rail rod 14 and the docking block 13. During the rotation process, the first rack rod 15 will contact the inclined wall on the transmission sleeve 16, and then the first rack rod 15 will be squeezed along the inclined wall of the transmission sleeve 16 to slide along the connecting rod 22 and stretch the reset spring 21 As the connecting plate 10 rotates, when the first rack rod 15 enters the inside of the transmission sleeve 16, the first rack rod 15 will be pulled back to its original position under the elastic force of the reset spring 21, so that the first rack rod 15 slides to a position meshing with the fixed gear 17, and then the battery to be punctured is placed on the base 6 again. At this time, when puncturing again, a new puncture rod 11 is used to puncture the battery, and the previously used puncture rod 11 will slide downward as the hydraulic rod 7 is pressed down. At this time, since the first rack rod 15 is located at the bottom of the connecting plate 10, when the connecting plate 10 slides downward, it will drive the first rack rod 15 to slide downward together, and the first rack rod 15 drives the screw rod 23 to slide down, so that the connecting gear 18 at one end of the screw rod 23 meshes with the second rack rod 19 and rotates. The rotation of the connecting gear 18 will drive the screw rod 23 to rotate, so that the connecting rod 22 threadedly connected to the screw rod 23 compresses the return spring 21. When the return spring 21 can no longer be compressed, the connecting rod 22 will drive the first rack rod 15 to slide together, and the sliding first rack rod 15 will drive the fixed gear 17 to rotate, and the fixed gear 17 will drive the puncture rod 11 to rotate together. The rotating puncture rod 11 extends into the interior of the soaking cylinder 12, and reacts with the acid and alkali solution inside the soaking cylinder 12 to neutralize the chemical battery liquid attached to the surface of the puncture rod 11 through a chemical reaction to generate a precipitate, and is separated from the surface of the puncture rod 11 by contact with the friction cylinder 29. The rotating puncture rod 11 can fully contact the side wall of the friction cylinder 29 until the impurities attached to its surface are completely cleaned. After the puncture test is completed, the hydraulic rod 7 drives the connecting plate 10 to reset. When the connecting plate 10 slides upward, the cylinder 28 is pushed to drive the clamping sleeve 26 to slide toward the inside of the soaking cylinder 12, so that the two foam blocks 25 clamp the puncture rod 11 from both sides. The foam blocks 25 contact the surface of the puncture rod 11 to clean the moisture on the surface of the puncture rod 11, and at the same time, the impurities remaining on the surface of the puncture rod 11 can be further removed. After the connecting plate 10 is reset, the connecting plate 10 is rotated again by rotating the motor 2 so that the positions of the two puncture rods 11 are swapped, so that the treated puncture rod 11 performs the puncture test on the battery again, and the puncture rod 11 after use will enter the inside of the soaking cylinder 12 to clean the surface battery liquid. The advantage of this is that the puncture test of the battery isThe post-puncture cleaning of the puncture rod 11 is carried out simultaneously. It is not necessary to clean the puncture rod 11 separately after the puncture is completed before using it for the puncture experiment. This can effectively improve the efficiency of the puncture experiment. By rotating the puncture rod 11 to contact the friction cylinder 29, impurities attached to the surface of the puncture rod 11 can be cleaned and then provided to the foam block 25 to absorb the moisture attached to the surface of the puncture rod 11 after soaking.

[0019] As a further solution of the present invention, the side wall of the outer frame 3 is fixedly connected to a fire extinguisher 4, and the front and rear ends of the outer frame 3 are respectively fixedly connected to a nozzle 5, and the input ends of the two nozzles 5 are respectively connected to the fire extinguisher 4; When the above solution is put into actual use, during a puncture test, the battery may sometimes catch fire due to squeezing and puncturing. The fire extinguisher 4 sprays foam to extinguish the fire, which can improve safety and avoid fire.

[0020] As a further solution of the present invention, the chute plate 20 is slidably connected to a limit rod 30, and the first rack rod 15 is provided with a docking ring for slidably connecting to the limit rod 30; When the above solution is put into actual use, the limiting rod 30 improves the overall stability of the first rack rod 15, so that the first rack rod 15 is more stable when the connecting plate 10 pushes the first rack rod 15 to slide up and down.

[0021] A method for testing a prismatic battery module, the method comprising the following steps: Step 1: Place the square battery module to be punctured on the base 6 stably; Step 2: Use the hydraulic rod 7 to drive the puncture rod 11 downward to perform a puncture test on the battery module, and observe the corresponding experimental data through the console 1; Step 3: After the puncture is completed, the puncture rod 11 is cleaned by the neutralization and cleaning component to clean off the chemical components attached to the surface after puncturing the battery; Step 4: Replace the battery module with a new one and repeat the puncture test.

[0022] Working principle: When conducting a puncture experiment, the square battery module to be punctured is placed steadily on the base 6, and the puncture rod 11 is driven downward by the hydraulic rod 7 to perform a puncture experiment on the battery module. The corresponding experimental data is observed through the console 1, and the hydraulic rod 7 is started to push the connecting plate 10 down, so that the telescopic rod 9 is stretched, and the puncture rod 11 on the top of the base 6 directly punctures the battery for the experiment. After the experiment is completed, the hydraulic rod 7 drives the puncture rod 11 to reset, and then the rotating motor 2 is started to drive the telescopic rod 9 to rotate, and the telescopic rod 9 drives the connecting plate 10 to rotate, so that the connecting plate 10 rotates 180 degrees to swap the positions of the two puncture rods 11 at the bottom, and the rotation position is determined by rotating the docking rail rod 14 and the docking block 13. During the rotation process, the first rack rod 1 5 will contact the inclined wall on the transmission sleeve 16, and then the first rack rod 15 will be squeezed along the inclined wall of the transmission sleeve 16 to slide along the connecting rod 22 and stretch the reset spring 21. As the connecting plate 10 rotates, when the first rack rod 15 enters the interior of the transmission sleeve 16, the elastic force of the reset spring 21 will pull the first rack rod 15 back to its original position, so that the first rack rod 15 slides to a position engaged with the fixed gear 17, and then the battery to be punctured is placed on the base 6 again. When puncturing again, a new puncture rod 11 is used to puncture the battery, and the previously used puncture rod 11 will slide downward as the hydraulic rod 7 is pressed downward. At this time, since the first rack rod 15 is located at the bottom of the connecting plate 10, when the connecting plate 10 is downward, When sliding, it will drive the first rack rod 15 to slide downward, and the first rack rod 15 will drive the screw rod 23 to slide down, so that the connecting gear 18 at one end of the screw rod 23 is meshed and rotated with the second rack rod 19. The rotation of the connecting gear 18 will drive the screw rod 23 to rotate, so that the connecting rod 22 threadedly connected to the screw rod 23 compresses the reset spring 21. When the reset spring 21 can no longer be compressed, the connecting rod 22 will drive the first rack rod 15 to slide together, and the sliding first rack rod 15 will drive the fixed gear 17 to rotate, and the fixed gear 17 will drive the puncture rod 11 to rotate together. The rotating puncture rod 11 extends into the interior of the soaking cylinder 12, and reacts with the acid and alkali solution inside the soaking cylinder 12 to neutralize the chemical battery liquid attached to the surface of the puncture rod 11 through a chemical reaction. The precipitate is generated and separated from the surface of the puncture rod 11 by contacting the friction cylinder 29. The rotating puncture rod 11 can fully contact the side wall of the friction cylinder 29 until the impurities attached to its surface are completely cleaned. Then, after the puncture experiment is completed, the hydraulic rod 7 drives the connecting plate 10 to reset. When the connecting plate 10 slides upward, the cylinder 28 is pushed to drive the clamping sleeve 26 to slide toward the inside of the soaking cylinder 12, so that the two foam blocks 25 clamp the puncture rod 11 from both sides. The foam blocks 25 contact the surface of the puncture rod 11 to clean the moisture on the surface of the puncture rod 11, and at the same time, the impurities remaining on the surface of the puncture rod 11 can be further removed. After the connecting plate 10 is reset, the connecting plate 10 is rotated again by rotating the motor 2 to swap the positions of the two puncture rods 11.The treated puncture rod 11 is used to perform a puncture test on the battery again, and the used puncture rod 11 enters the soaking cylinder 12 to clean the surface battery fluid.

Claims

1. A testing device for a square battery module, comprising an outer frame (3), wherein the bottom of the outer frame (3) is fixedly connected to a base (6), the top of the outer frame (3) is fixedly connected to a hydraulic rod (7), the output end of the hydraulic rod (7) is provided with a puncture rod (11), one side of the outer frame (3) is fixedly connected to a console (1), and a neutralization and cleaning component is provided inside the outer frame (3), wherein the neutralization and cleaning component is used to clean off chemical components on the puncture rod (11) after puncturing the battery.

2. The testing device for a square battery module according to claim 1, characterized in that: The neutralization and cleaning component includes a connecting plate (10), which is arranged inside the outer frame (3), and the bottom two sides of the connecting plate (10) are respectively fixedly connected to the puncture rod (11), and the top two sides of the connecting plate (10) are respectively fixedly connected to the docking rail rod (14), and the bottom output shaft of the hydraulic rod (7) is fixedly connected to a docking block (13) for rotatably connecting to the docking rail rod (14), and the top of the connecting plate (10) is fixedly connected to the telescopic rod (9), and the top of the outer frame (3) is fixedly connected to the sleeve (8), and the output shaft of the telescopic rod (9) is rotatably connected to the sleeve (8), and the top of the outer frame (3) is fixedly connected to a rotating motor (2), and the output shaft of the rotating motor (2) passes through the outer frame (3) and is fixedly connected to the output shaft of the telescopic rod (9) inside the sleeve (8), and the bottom of the outer frame (3) is fixedly connected to a soaking cylinder (12).

3. The testing device for a square battery module according to claim 2, characterized in that: The top end of the puncture rod (11) is fixedly connected to a fixed gear (17), the side wall of the outer frame (3) is fixedly connected to a slide plate (20), the interior of the slide plate (20) is slidably connected to a screw rod (23), one end of the screw rod (23) is spirally sleeved with a connecting rod (22), the outside of the connecting rod (22) is slidably connected to a first rack rod (15), and one end of the connecting rod (22) is fixedly connected to a reset spring (21) for resetting the first rack rod (15).

4. The testing device for a square battery module according to claim 3, characterized in that: The side wall of the chute plate (20) is fixedly connected to a second rack rod (19), the screw rod (23) is fixedly connected to a connecting gear (18) for meshing with the second rack rod (19), and the two side walls of the connecting plate (10) are respectively fixedly connected to a transmission sleeve (16).

5. The testing device for a square battery module according to claim 2, characterized in that: The top of the soaking cylinder (12) is fixedly connected to a fixing plate (24), both sides of the fixing plate (24) are fixedly connected to a pushing cylinder (28), the top of the fixing plate (24) is fixedly connected to a fixing shaft (27), a clamping sleeve (26) is slidably connected to the fixing shaft (27), and the output end of the pushing cylinder (28) is fixedly connected to the clamping sleeve (26).

6. The testing device for a prismatic battery module according to claim 2, wherein: A friction cylinder (29) for docking with the puncture rod (11) is provided inside the soaking cylinder (12).

7. The testing device for a prismatic battery module according to claim 5, characterized in that: A foam block (25) with strong water absorption is fixedly connected to the inner wall of the clamping sleeve (26).

8. The testing device for a prismatic battery module according to claim 2, wherein: The side wall of the outer frame (3) is fixedly connected to a fire extinguisher (4), and the front and rear ends of the outer frame (3) are respectively fixedly connected to nozzles (5), and the input ends of the two nozzles (5) are respectively connected to the fire extinguisher (4).

9. The testing device for a prismatic battery module according to claim 3, wherein: The chute plate (20) is slidably connected to a limit rod (30), and the first rack rod (15) is provided with a docking ring for slidably connecting to the limit rod (30).

10. A method for testing a prismatic battery module, applicable to the testing device for a prismatic battery module according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: Step 1: placing the electrode sheet whose tabs need to be cut off on a conveying rack (4) for conveying; Step 2: The electrode sheet is transported to the top of the bottom plate (6) via the conveyor frame (4) and contacts the side baffle (5) to limit its displacement; Step 3: The hydraulic assembly (2) drives the fixed frame (3) to slide down until the electrode sheet is pressed tightly, and then the electrode ear is cut off by the cutting plate (19); Step 4: After the tab is cut, the polishing mechanism polishes the cut portion of the tab to remove burrs at the cut portion.

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