A method for laser cutting of pole piece material area and pole piece
Through the laser cutting method, the lithium battery electrode sheet is cut and trimmed by different peak powers and pulse widths of the first laser and the second laser, which solves the problems of burrs and beads after cutting, and improves the safety performance of the battery.
Patent Information
- Application Number
- CN202411924995.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2025-04-04
AI Technical Summary
Lithium battery electrodes are easily cut and burrs and molten beads are likely to occur, affecting the safety performance of the battery.
Using a laser cutting method, the workpiece is pretreated by controlling the first laser, and then discontinuously offset cutting of the cutting edges, melting burrs and melting beads are performed using a second laser with a peak power less than the first laser.
It effectively solves the problems of burrs and molten beads after the pole sheet is cut, improves the safety performance of the battery, and obtains a burr-free and molten bead-free end face.
Smart Images
Figure CN119747911A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of lithium battery pole piece production technology, and in particular relates to a pole piece material area laser cutting method and a pole piece. Background Art
[0002] Lithium battery cells are usually composed of positive and negative electrodes, separators and electrolytes. Cell manufacturing is a mid-stage process in the entire battery production process, which usually includes die-cutting, lamination / winding, packaging and liquid injection.
[0003] The end face produced by traditional cutting is prone to produce large burrs and large molten beads, which will affect the safety performance of the battery.
[0004] Therefore, in the production and cutting of lithium battery pole pieces, a cutting method with good cutting rear end surface quality and high cutting efficiency is urgently needed to replace traditional knife die cutting. Summary of the invention
[0005] The present invention provides a method for laser cutting a pole piece material area and a pole piece, which can effectively solve the problem of burrs and melt beads generated after the pole piece is cut, thereby improving the safety performance of the battery.
[0006] In order to achieve the above object, the present invention adopts the following technical scheme:
[0007] In a first aspect, the present invention provides a method for laser cutting a polar sheet material area, comprising:
[0008] Controlling a first laser to process a workpiece, wherein an end surface of a cutting edge of the workpiece after the first laser processing has burrs and molten beads;
[0009] Controlling the second laser to discontinuously deflect on the cutting edge to process the burrs and molten beads;
[0010] The peak power of the second laser is smaller than the peak power of the first laser.
[0011] According to some embodiments of the present invention, the second laser comprises a plurality of second lasers, and the plurality of second lasers sequentially perform discontinuous offset cutting on the cutting edge.
[0012] According to some embodiments of the present invention, the multiple times of sequentially performing offset cutting with the second laser include:
[0013] The multiple second lasers perform discontinuous offset cutting on the cutting edge in sequence at preset intervals.
[0014] According to some embodiments of the present invention, the offset direction of the second laser is discontinuously offset from the inside to the outside of the cutting edge.
[0015] According to some embodiments of the present invention, the peak power of the first laser is 2 to 5 times the peak power of the second laser.
[0016] According to some embodiments of the present invention, the first laser pulse width is 100-500ns, the average power is 80-90W, and the frequency is 200-250khz; the second laser pulse width is 10-30ns, the average power is 10-20W, and the frequency is 1000-2000khz.
[0017] According to some embodiments of the present invention, before controlling the first laser to cut the workpiece along the first cutting trajectory, the laser cutting method further includes:
[0018] The workpiece is die-cut and formed according to the first cutting trajectory.
[0019] According to some embodiments of the present invention, after offset cutting the end surface of the edge of the first cutting track of the workpiece with a second laser, the laser cutting method further comprises:
[0020] The workpiece is cut according to the second cutting trajectory.
[0021] According to some embodiments of the present invention, cutting the workpiece according to the second cutting trajectory further comprises:
[0022] A plurality of sequentially arranged field lenses are configured to perform laser cutting on the workpiece respectively, and the plurality of field lenses control the movement of the laser on the workpiece along a portion of the second cutting track to achieve cutting of the workpiece according to the second cutting track.
[0023] In a second aspect, the present invention provides a pole piece, which is cut by the laser cutting method as described in any one of the first aspects.
[0024] The beneficial effects of the present invention compared with the prior art are:
[0025] The pole piece material area laser cutting method provided by the present invention controls a first laser to pre-treat the pole piece cutting surface after tool or laser die-cutting, and controls a second laser with a power smaller than that of the first laser to melt the burrs and molten beads generated when the first laser cuts the pole piece, thereby trimming the pole piece cutting edge to avoid the harm caused by the burrs and molten beads, obtain a burr-free and molten bead-free end face, and improve the safety performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.
[0027] Figure 1 One of the flow charts of the method for laser cutting of the pole piece material area provided in an embodiment of the present invention;
[0028] Figure 2 A schematic diagram of a process for melting a molten bead using a second laser provided in an embodiment of the present invention;
[0029] Figure 3 Flow chart 2 of the method for laser cutting of the pole piece material area provided in an embodiment of the present invention;
[0030] Figure 4 Flow chart three of the method for laser cutting of the pole piece material area provided in an embodiment of the present invention;
[0031] Figure 5 A schematic diagram of a first laser processing trajectory of a pole piece provided in an embodiment of the present invention;
[0032] Figure 6 A schematic diagram of a laser die-cutting process provided by an embodiment of the present invention, wherein arrows indicate the direction of movement of the workpiece;
[0033] Figure 7 A schematic diagram of a laser cleaning and repair process provided by an embodiment of the present invention;
[0034] Figure 8 A schematic diagram of a laser cutting process provided by an embodiment of the present invention.
[0035] 1. Foil area; 2. Material area; 21. Tab; 31. First cutting track; 32. Second cutting track; 41. First die-cutting station; 42. Second die-cutting station; 43. Third die-cutting station; 51. First cleaning station; 52. Second cleaning station; 53. Third cleaning station; 6. Melt bead; 61. Second laser A; 610. Galvanometer; 611. Field lens; 62. Second laser B; 63. Second laser C; 71. First cutting station; 72. Second cutting station; 73. Third cutting station; 74. Fourth cutting station. DETAILED DESCRIPTION
[0036] The following description provides specific application scenarios and requirements of this specification, with the purpose of enabling those skilled in the art to make and use the contents of this specification. Various local modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of this specification. Therefore, this specification is not limited to the embodiments shown, but to the widest scope consistent with the claims.
[0037] The existing battery cell stacking cutting solution on the market uses traditional physical cutting dies for cutting. Hardware cutting dies face shortcomings such as poor changeover capability, low flexibility, frequent replacement of consumables, and high downtime costs. Traditional cutting has quality problems such as large end face burrs and large melt beads, and there is an urgent need to reduce the harm caused by cutting burrs.
[0038] The present invention uses laser cutting. Compared with hardware die cutting, laser cutting has the advantages of more convenient model change, high cutting efficiency, high cutting precision, high cutting quality, low maintenance cost, and wide application range. It is imperative to replace the traditional die cutting solution with a laser solution.
[0039] First, as Figure 1-Figure 8 As shown, the present invention provides a method for laser cutting of a pole piece material area 2, comprising the following steps:
[0040] S1, controlling a first laser to process a workpiece, wherein the end surface of the cut edge of the workpiece after the first laser processing has burrs and molten beads 6;
[0041] S2. Control the second laser to discontinuously offset on the cutting edge to process the burrs and molten beads 6; wherein the peak power of the second laser is less than the peak power of the first laser.
[0042] The laser cutting method of the pole piece material area 2 provided by the present invention controls the first laser to pre-treat the cut surface of the pole piece material area 2 after the tool or laser die-cutting, and controls the second laser with a power smaller than the first laser to melt the burrs and molten beads 6 generated when the first laser cuts the pole piece material area 2, thereby trimming the cut edge of the pole piece material area 2 to avoid the harm caused by the burrs and molten beads 6, obtain an end face without burrs and molten beads 6, and improve the safety performance of the battery.
[0043] In this embodiment, the workpiece of the present invention can be a tab 21, which is obtained by cutting the foil area 1 and the material area 2. The first laser is controlled to process the cut portion of the material area 2 of the die-cut tab 21, and then the burrs and molten beads 6 generated by the first laser treatment at the cutting edge of the material area 2 of the tab 21 are melted by the second laser to avoid the hazards of no burrs and no molten beads 6, thereby improving the safety performance of the battery. Of course, the workpiece of the present application can also be other types of workpieces, which can be determined by those skilled in the art according to the actual situation, and are not specifically limited here.
[0044] In the above step S1, the power of the first laser is used to pre-treat the workpiece to remove the generated burrs, melt beads 6, etc. Therefore, the power of the first laser does not need to be too large, and can be controlled at 80-90% of the laser power for laser die-cutting the workpiece. Preferably, the power of the first laser is 90% of the laser power for laser die-cutting the workpiece.
[0045] After step S1 is completed, step S2 can be started, that is, controlling the second laser to discontinuously offset on the cutting edge to process the burrs and molten beads 6. The first laser and the second laser can be lasers emitted by the same laser. The laser first emits the first laser to process the workpiece, and then returns to the initial position and emits the second laser to process the burrs and molten beads 6 on the end surface of the cutting edge of the workpiece after the first laser processing. The first laser and the second laser can also be lasers emitted by different lasers. Different lasers can move along the same trajectory in spatial positions. After the laser of the first laser completes the operation, the laser of the second laser starts to work.
[0046] like Figure 2 As shown, since the laser is V-shaped focused, the generated cutting edge profile has a taper, and the peak power of the second laser is small, the repair energy is very small, resulting in a small range of lateral repair, so it is necessary to offset discontinuously on the cutting edge. In other words, the second laser performs discontinuous offset cutting at equal intervals or predetermined intervals, thereby repairing the entire cutting edge profile and processing the burrs and molten beads 6.
[0047] It should be noted that the discontinuous offset mentioned here means that the moving direction of the second laser is different from the cutting edge direction. In other words, the second laser can be translated while moving along the cutting edge direction, thereby increasing the area processed by the second laser and processing a single molten bead 6. In one embodiment, the second laser can be a continuous laser, but the second laser path emitted by it is curved relative to the cutting edge.
[0048] The second laser laser A61, the second laser laser B62 and the second laser laser C63 are the same laser at different cutting edge positions. At this time, when the second laser laser is in the positions of the second laser laser A61, the second laser laser B62 and the second laser laser C63 in sequence, it will emit the second laser in sequence. That is, the second laser includes multiple second lasers, and the multiple second lasers perform discontinuous offset cutting in sequence on the cutting edge.
[0049] Taking the second laser A61 as an example, the second laser A61 includes a galvanometer 610 and a field lens 611. The galvanometer 610 controls the rapid deflection and precise positioning of the laser, and controls the movement trajectory of the laser on the workpiece surface through high-speed and precise swing. The field lens 611 forms a focused light spot of uniform size on the entire marking plane to ensure that the size and shape of the laser on the marking plane remain unchanged. In this embodiment, the selection of the galvanometer 610 and the field lens 611 used in each laser station can be adaptively adjusted according to the specific workpiece and process to be processed, and is not specifically limited here.
[0050] In another embodiment, the second laser A61, the second laser B62 and the second laser C63 may be different lasers, and the processing of the same cutting edge by different lasers is achieved by fixing the lasers of the second lasers and moving the workpiece.
[0051] In order to facilitate the control of the operation of the second laser, the mode of emitting multiple second lasers by one laser is adjusted so that the laser emits the second laser multiple times in sequence at a preset interval. It should be noted that the above-mentioned preset interval refers to the preset interval in the direction of the cutting edge, so the second laser can move in the direction close to or away from the cutting edge at the preset interval.
[0052] The second laser needs to be processed with a small pulse width and low energy to prevent over-repair from producing worse results. At the same time, in order to avoid burrs and molten beads 6 generated by the second laser during processing, the offset direction of the second laser is discontinuously offset from the inside to the outside of the cutting edge. When the second laser is processing the R corner of the pole ear 21, the speed needs to be slightly reduced to provide the galvanometer 610 motor with sufficient turning response time.
[0053] In addition, the peak power of the second laser is less than the peak power of the first laser. The peak power of the laser in pulse mode = pulse energy divided by pulse width, and the average power = pulse energy × frequency; when the laser is in continuous mode, the average power is equal to the peak power, and the peak power is proportional to the energy of the laser on the workpiece. The greater the peak power, the greater the laser energy. Therefore, the first laser with a higher peak power is selected for preliminary processing, and the second laser uses a laser with a weaker energy than the first laser to process the burrs and beads 6. Specifically, the peak power of the first laser is 2 to 5 times the peak power of the second laser, so as to achieve the effect of melting burrs and beads 6 without affecting the quality of the workpiece. Preferably, the peak power of the first laser is 2, 3, or 5 times the peak power of the second laser.
[0054] More specifically, in order to adjust the peak power, the first laser pulse width is 100-500ns, the average power is 80-90W, and the frequency is 200-250khz; the second laser pulse width is 10-30ns, the average power is 10-20W, and the frequency is 1000-2000khz. Preferably, the first laser pulse width is 200ns, the average power is 80W, and the frequency is 200khz; the second laser pulse width is 10ns, the average power is 20W, and the frequency is 1000khz.
[0055] In order to realize the integration of laser processing technology in material area 2, such as Figure 3 , Figure 5 and Figure 6As shown, before controlling the first laser to cut the workpiece along the first cutting track 31, the laser cutting method further includes: die-cutting the workpiece according to the first cutting track 31. The first laser treatment and the second laser treatment belong to the cleaning and repair process. In order to be able to combine with the cleaning and repair process, the die-cutting process also uses laser treatment. Specifically, the shape of the tab 21 is die-cut by using the laser power conversion and frequency conversion technology at different positions of the tab 21 image. Please refer to Figure 6 The first die-cutting station 41, the second die-cutting station 42 and the third die-cutting station 43 are arranged along the workpiece moving belt direction, and the material area 2 located in the cutting area is laser cut respectively to form the pole ear 21. It can be understood that in another embodiment, the die-cutting can also be performed by disc shear slitting or mold punching, and after the die-cutting process is completed, it is transferred to the subsequent first laser and second laser cleaning and repair processes.
[0056] See also Figure 7 , is a schematic diagram of the laser cleaning and repair process. In this process, the first laser and the second laser are lasers emitted by the same laser. Specifically, the first cleaning station 51, the second cleaning station 52 and the third cleaning station 53 are arranged along the workpiece moving belt direction, and respectively clean and repair the die-cut and finalized pole ear 21. After the first laser pretreatment is completed, the second laser is used to treat the burrs and molten beads 6 after the first laser treatment.
[0057] In order to realize the integration of cleaning and repair process and cutting process, such as Figure 4 and Figure 5 As shown, after the end face of the edge of the first cutting track 31 of the workpiece is offset cut by the second laser, the laser cutting method further includes: cutting the workpiece according to the second cutting track 32. The cutting process also uses laser cutting to facilitate the integration of the die-cutting process, the cleaning and repair process, and the cutting process. Since the width of the field lens 611 is limited, and the width of the pole sheet material area 2 is often large, such as Figure 8 As shown, when cutting the electrode sheet material area 2, multiple sequentially arranged field lenses 611 are configured to perform laser cutting on the workpiece respectively. The multiple field lenses 611 control the movement of the laser on the workpiece along part of the second cutting track 32 to achieve cutting of the workpiece according to the second cutting track 32. Specifically, a first cutting station 71, a second cutting station 72, a third cutting station 73 and a fourth cutting station 74 are sequentially arranged from top to bottom along the TD direction. The four cutting stations move along a part of the second cutting track 32 respectively, and are combined to achieve cutting of the electrode workpiece along the second cutting track 32.
[0058] In a second aspect, the present invention further provides a pole piece, which is cut by the pole piece material area laser cutting method provided in any of the above embodiments, so that the end surface of the pole piece is free of burrs and melt beads 6, thereby improving the safety performance of the battery.
[0059] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or substitutions within the technical scope disclosed by the present invention, and these modifications or substitutions should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.
Claims
1. A method for laser cutting of a pole sheet area, characterized in that: include: Controlling a first laser to process a workpiece, wherein an end surface of a cutting edge of the workpiece after the first laser processing has burrs and molten beads; Controlling the second laser to discontinuously deflect on the cutting edge to process the burrs and molten beads; The peak power of the second laser is smaller than the peak power of the first laser.
2. The method for laser cutting of the pole piece area according to claim 1, characterized in that: The second laser includes multiple second lasers, and the multiple second lasers sequentially perform discontinuous offset cutting on the cutting edge.
3. The method for laser cutting of the pole piece area according to claim 2, characterized in that: The multiple times of second laser cutting in sequence include: The multiple second lasers perform discontinuous offset cutting on the cutting edge in sequence at preset intervals.
4. The method for laser cutting of the pole piece area according to claim 1, characterized in that: The offset direction of the second laser is discontinuously offset from the inside to the outside of the cutting edge.
5. The method for laser cutting of the pole piece area according to claim 1, characterized in that: The peak power of the first laser is 2 to 5 times the peak power of the second laser.
6. The method for laser cutting of the pole piece area according to claim 1, characterized in that: The first laser pulse width is 100-500ns, the average power is 80-90W, and the frequency is 200-250khz; the second laser pulse width is 10-30ns, the average power is 10-20W, and the frequency is 1000-2000khz.
7. The method for laser cutting of the pole piece area according to claim 1, characterized in that: Before controlling the first laser to cut the workpiece along the first cutting trajectory, the laser cutting method further includes: The workpiece is die-cut and formed according to the first cutting trajectory.
8. The method for laser cutting of the pole piece area according to claim 1, characterized in that: After performing offset cutting on the end surface of the edge of the first cutting track of the workpiece with a second laser, the laser cutting method further comprises: The workpiece is cut according to the second cutting trajectory.
9. The method for laser cutting of the pole piece area according to claim 8, characterized in that: The cutting of the workpiece according to the second cutting trajectory further comprises: A plurality of sequentially arranged field lenses are configured to perform laser cutting on the workpiece respectively, and the plurality of field lenses control the movement of the laser on the workpiece along a portion of the second cutting track to achieve cutting of the workpiece according to the second cutting track.
10. A pole piece, characterized in that: It is cut by the pole piece material area laser cutting method as described in any one of claims 1 to 9.