Method and system for improving dimensional accuracy of laser die-cutting, terminal, and storage medium

Abstract

A method for improving the dimensional accuracy of laser die-cutting, comprising: performing laser die-cutting to obtain a first MARK hole in an electrode web, and starting to record a movement distance of the electrode web with the first MARK hole as a starting point; sequentially performing laser die-cutting at positions at distances L 1, L 2, ..., L n-1 from the first MARK hole on the electrode web to form tabs of predetermined shapes; performing laser die-cutting at the position at the distance L n from the first MARK hole on the electrode web to obtain a second MARK hole, and starting to record the movement distance of the electrode web with the second MARK hole as a starting point; sequentially performing laser die-cutting at positions at distances L 1, L 2, ..., L n-1 from the second MARK hole on the electrode web to form tabs of predetermined shapes; performing laser die-cutting at the position at the distance L n from the second MARK hole to obtain a third MARK hole; and repeating this process until the laser die-cutting of one roll of material is completed. The method avoids the accumulation of cutting deviations, reduces the scrapping of electrode plates and separators caused by large tab misalignment, and improves the winding yield and production efficiency. The present invention further relates to a system for improving the dimensional accuracy of laser die-cutting, a terminal, and a storage medium.

Description

Methods, systems, terminals, and storage media for improving the dimensional accuracy of laser die-cutting

[0001] This application claims priority to Chinese Patent Application No. 2024117524328, filed on December 2, 2024, entitled "A method and system, terminal and storage medium for improving the dimensional accuracy of laser die-cutting", the contents of which are incorporated herein by reference in their entirety as part of this application. Technical Field

[0002] This disclosure relates to the field of electrode laser die-cutting technology, and in particular to a method, system, terminal and storage medium for improving the dimensional accuracy of laser die-cutting. Background Technology

[0003] With the development of renewable energy worldwide, lithium-ion batteries have gained significant attention from the industry due to their high voltage, high capacity, and stable material structure. Currently, with the rapid development of photovoltaic and wind power storage power stations, lithium batteries, as the core of power energy, are ushering in market development globally.

[0004] Laser die-cutting, a crucial component of lithium-ion battery production, involves using a laser to cut the positive and negative electrode sheets to the required width and corresponding dimensions for each tab spacing. This ensures the alignment of the tabs during the subsequent winding process, which involves winding the positive electrode sheet, separator, and negative electrode sheet into a single core unit. In the production of wound cells, the accuracy of the die-cutting dimensions is critical to ensuring the alignment of the tabs. The existing laser die-cutting logic and schematic diagram are shown in Figures 1 and 2. During laser die-cutting, the PLC first defines the MARK hole as the starting position and begins laser cutting from that position. After completing the first spacing L1, the PLC redefines this position (L1 distance from the MARK hole) as the starting position, calculates using an encoder, and performs laser cutting to complete the second spacing L2. This process is repeated to complete the tab spacing cutting, laser-cutting the entire die-cut size, and producing a complete core strip. However, this process suffers from several drawbacks. After each laser cut, the PLC needs to redefine the starting position. Each laser cut requires the equipment to calculate the material travel distance from this new starting position. Due to the precision limitations of the laser cutter, deviations in the travel distance can occur. When n intervals are cut, some or all of the tab spacing deviations can accumulate, leading to significant misalignment of the core tabs. After die-cutting, this misalignment exceeds the process parameters, preventing subsequent ultrasonic welding from fully depositing the weld mark on the tabs, resulting in the entire core being scrapped. For example, a product with a single positive core electrode length of 21038mm and a single negative core electrode length of 21601mm requires laser cutting of the tabs using this logic. If this spacing deviation accumulates, a 21038mm long positive electrode strip, a 21601mm long negative electrode strip, and a 45192mm long diaphragm strip must be discarded, resulting in significant material waste and reduced winding yield and production efficiency. Summary of the Invention

[0005] Based on this, the purpose of this disclosure is to provide a method, system, terminal, and storage medium for improving the dimensional accuracy of laser die-cutting, in order to solve the technical problem that existing laser cutting methods suffer from the superposition of partial or complete tab spacing deviations, resulting in large misalignment of the winding tabs and causing material scrap.

[0006] To achieve the above objectives, the present disclosure adopts the following technical solution:

[0007] This disclosure first provides a method for improving the dimensional accuracy of laser die-cutting, which includes the following steps:

[0008] S1. Drive the coiled material to release the electrode strip and drive the electrode strip to move in a predetermined direction;

[0009] S2. Laser-cut the first MARK hole on the electrode strip, and start recording the moving distance of the electrode strip from the first MARK hole as the starting point;

[0010] S3. On the electrode strip, at distances L1, L2, ..., L from the first MARK hole n-1 The positions are sequentially laser-cut to form tabs of a predetermined shape; where n is a positive integer, L1, L2, ..., L... n-1 Increase sequentially;

[0011] S4. On the electrode strip, at a distance L from the first MARK hole n The second MARK hole is laser-cut at the position, and the movement distance of the electrode strip is recorded starting from the second MARK hole;

[0012] S5. On the electrode strip, at distances L1, L2, ..., L from the second MARK hole n-1 The positions are sequentially laser-cut to form tabs of a predetermined shape, at a distance L from the second MARK hole. n The third MARK hole is laser-cut at the position; this process is repeated until the laser die-cutting of a roll of material is completed.

[0013] According to one or more embodiments of this disclosure, in step S2, at a distance L from the end of the electrode strip... x The first MARK hole is laser-cut at the position.

[0014] According to one or more embodiments of this disclosure, in step S4, L n Greater than L n-1 .

[0015] According to one or more embodiments of this disclosure, the laser die-cutting of the electrode tabs of a predetermined shape involves laser die-cutting the electrode tabs of a predetermined shape on both sides of the electrode strip along its length.

[0016] This disclosure also proposes a device for improving the dimensional accuracy of laser die-cutting, comprising:

[0017] The feeding mechanism is configured to drive the coiled material to release the electrode strip and drive the electrode strip to move in a predetermined direction;

[0018] A laser die-cutting mechanism is configured to laser-die-cut the electrode strip to form electrode tabs and mark holes; and

[0019] A controller, connected to the conveying mechanism and the laser die-cutting mechanism, is configured to: control the conveying mechanism to drive the electrode strip to move in a predetermined direction; control the laser die-cutting mechanism to laser-die-cut the first MARK hole on the electrode strip and record the moving distance of the electrode strip starting from the first MARK hole; and control the laser die-cutting mechanism to move at distances L1, L2, ..., L from the first MARK hole. n-1 The laser die-cutting mechanism is sequentially performed at various positions to form tabs of a predetermined shape, and the laser die-cutting mechanism is controlled to operate at a distance L from the first MARK hole. n The second MARK hole is laser-cut at the specified position; then, using the second MARK hole as the starting point, the laser die-cutting mechanism is controlled to move along the electrode strip at distances L1, L2, ..., L from the second MARK hole. n-1 The positions are sequentially laser-cut to form electrode tabs of a predetermined shape, with a distance L from the second MARK hole on the electrode strip. n The third MARK hole is laser-cut at the specified position; this process is repeated until the laser die-cutting of a roll of material is completed; where n is a positive integer, L1, L2, ..., L... n-1 L n Increase sequentially.

[0020] According to one or more embodiments of this disclosure, the device further includes an encoder electrically connected to the controller and configured to record the distance traveled by the electrode strip.

[0021] According to one or more embodiments of this disclosure, the feeding mechanism includes an unwinding mechanism and a conveying mechanism. The unwinding mechanism is connected to the controller and controlled by the controller to release electrode strip to the feed end of the conveying mechanism. The conveying mechanism is connected to the controller and controlled by the controller to convey the electrode strip released by the unwinding mechanism in a predetermined direction.

[0022] According to one or more embodiments of this disclosure, the device further includes a winding mechanism connected to the controller and controlled by the controller to wind up the laser-diced electrode strip from the discharge end of the conveying mechanism.

[0023] According to one or more embodiments of this disclosure, the laser die-cutting mechanism includes two lasers, which are respectively configured to perform laser die-cutting on both sides of the electrode strip along the length direction to form electrode tabs and MARK holes of predetermined shapes on both sides of the electrode strip along the length direction.

[0024] This disclosure also proposes a computer terminal including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the method for improving the dimensional accuracy of laser die-cutting as described above.

[0025] This disclosure also proposes a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method for improving the dimensional accuracy of laser die-cutting as described above.

[0026] Compared with the prior art, this disclosure has the following beneficial effects:

[0027] Throughout the laser cutting process, this disclosure calculates the distance the electrode strip travels from the position of the first MARK hole as the starting point, avoiding calculation deviations caused by repeatedly defining the starting point. This avoids deviations in the tab spacing of a single cut, prevents the accumulation of cutting deviations, reduces the scrap of electrodes and diaphragms caused by large tab misalignment, and improves winding yield and production efficiency. Attached Figure Description

[0028] Figure 1 is a flowchart of the existing laser cutting control process;

[0029] Figure 2 is a schematic diagram of the existing laser-cut electrode structure;

[0030] Figure 3 is a flowchart of a method for improving the dimensional accuracy of laser die-cutting in an embodiment of this disclosure;

[0031] Figure 4 is a schematic diagram of the electrode structure after laser cutting according to an embodiment of this disclosure. Detailed Implementation

[0032] To facilitate understanding of this disclosure, it will be described more fully below with reference to specific embodiments. However, this disclosure can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to enable a more thorough and complete understanding of the disclosure.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure.

[0034] First, it should be noted that a wound-type battery cell consists of a positive electrode, a negative electrode, and a separator. The separator is stacked between the positive and negative electrode sheets to form a "sandwich" structure. During winding, the positive electrode, negative electrode, and separator are wound together, with adjacent positive and negative electrode sheets isolated by the separator to prevent short circuits. The positive electrode includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector, and the uncoated positive current collector protrudes beyond the coated one, serving as the positive electrode tab. Similarly, the negative electrode includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector, and the uncoated negative current collector protrudes beyond the coated one, serving as the negative electrode tab. Electrode strips are formed into wound positive / negative electrodes through laser cutting. The coating area of ​​the electrode strip refers to the area on the current collector coated with an active material layer, while the tab area of ​​the electrode strip refers to the area on the current collector that is not coated with an active material layer, which is also the area where tabs are formed by cutting.

[0035] This embodiment first proposes a device for improving the dimensional accuracy of laser die-cutting, which is configured to cut electrode strips to form the electrodes of a wound battery cell. It includes a feeding mechanism, an encoder, a laser die-cutting mechanism, and a controller, and may also include a winding mechanism.

[0036] The feeding mechanism includes an unwinding mechanism and a conveying mechanism. The unwinding mechanism is configured to release the electrode strip. In this embodiment, a conventional unwinding device can be used for the unwinding mechanism, which mainly includes an unwinding shaft housing the electrode roll, an unwinding drive unit that drives the unwinding shaft to rotate and release the electrode strip, an unwinding correction assembly, and a cutter for cutting the electrode strip. The conveying mechanism is configured to transport the electrode strip released by the unwinding mechanism in a predetermined direction. In this embodiment, a conventional conveyor line can be used for the conveying mechanism.

[0037] The encoder can accurately measure the linear displacement of the electrode strip and convert it into digital signals. These digital signals can be used by the control system for further processing and analysis, thereby achieving precise control of motion parameters such as position.

[0038] The laser die-cutting mechanism utilizes a high-energy laser beam to irradiate the surface of the electrode strip, causing the strip to melt and evaporate, thereby forming tabs and mark holes. In this embodiment, the laser die-cutting mechanism includes two lasers. The two lasers are used to laser-die-cut the uncoated areas on both sides of the electrode strip's length direction to form tabs and mark holes of predetermined shapes on both sides. The lasers are conventional nanosecond pulsed fiber lasers, high-peak-value nanosecond pulsed fiber lasers, picosecond lasers, or femtosecond lasers.

[0039] The winding mechanism is used to wind up the laser-diced electrode strip. In this embodiment, the winding mechanism can be a conventional winding device. The winding mechanism mainly includes an unwinding shaft, a winding drive unit that drives the winding shaft to rotate to wind the electrode strip, and a winding correction component.

[0040] The controller (i.e., PLC) is electrically connected to the conveying mechanism, encoder, laser die-cutting mechanism, unwinding mechanism, and rewinding mechanism, and controls the operation of these mechanisms. Referring to Figure 3, the specific control logic of the controller in this embodiment is as follows:

[0041] S1. The controller controls the unwinding drive unit to start and drive the unwinding shaft to rotate, so as to release the electrode strip. One end of the electrode strip passes around the conveying mechanism and is fixed to the take-up shaft. Then the unwinding drive unit and the take-up drive unit start synchronously, and the conveying mechanism drives the electrode strip to move in a predetermined direction.

[0042] S2. The controller controls the laser to move at a distance L from the beginning of the electrode strip. x The first MARK hole is laser-cut at the designated position. The controller controls the encoder to measure the movement distance of the electrode strip starting from the first MARK hole. The controller obtains the movement distance of the electrode strip based on the feedback signal from the encoder. The controller then compares the movement distance of the electrode strip with preset displacements L1, L2, ..., L... n-1 L n Compare them separately; where n is a positive integer, L1, L2, ..., L n-1 L n Increasing sequentially, L x The length should be reasonably limited according to the actual situation.

[0043] S3. When the electrode strip has moved a distance equal to L1, the controller controls two lasers to perform laser die-cutting on both sides of the electrode strip, so as to laser-die-cut electrode tabs of a predetermined shape at a distance of L1 from the first MARK hole on both sides of the electrode strip; when the electrode strip has moved a distance equal to L2, the controller controls two lasers to perform laser die-cutting on both sides of the electrode strip, so as to laser-die-cut electrode tabs of a predetermined shape at a distance of L2 from the first MARK hole on both sides of the electrode strip; this process is repeated until the distance of L2 from the first MARK hole on both sides of the electrode strip is equal to L1. n-1 The electrode tabs of a predetermined shape are laser-cut at the designated positions.

[0044] S4. The controller controls the laser to be positioned at a distance L from the first MARK hole on the electrode strip. nThe second MARK hole is laser-cut at the designated position. The controller then instructs the encoder to restart measuring the electrode strip's movement distance from the second MARK hole. The controller obtains the electrode strip's movement distance based on the encoder's feedback signal. The controller then compares the electrode strip's movement distance with preset displacements L1, L2, ..., L... n-1 Compare them separately.

[0045] S5. When the electrode strip has moved a distance equal to L1, the controller controls the two lasers to perform laser die-cutting on both sides of the electrode strip, so as to laser-die-cut electrode tabs of a predetermined shape at a distance of L1 from the second MARK hole on both sides of the electrode strip; when the electrode strip has moved a distance equal to L2, the controller controls the two lasers to perform laser die-cutting on both sides of the electrode strip, so as to laser-die-cut electrode tabs of a predetermined shape at a distance of L2 from the second MARK hole on both sides of the electrode strip; this process is repeated until the distance of L2 from the second MARK hole on both sides of the electrode strip is equal to L1. n-1 The laser cuts out the predetermined shape of the tabs at the designated positions. This process is repeated until the laser cutting of a roll of material is completed.

[0046] Figure 4 shows the electrode strip after laser die-cutting in this embodiment. By optimizing the laser die-cutting process, this embodiment avoids the phenomenon of partial or complete electrode spacing deviation caused by the deviation of the electrode spacing in each laser cut, which would lead to the scrapping of the entire positive / negative electrode roll and the separator in the winding process. This greatly reduces the scrap rate of winding, improves the utilization rate and yield of winding materials, and saves production materials.

[0047] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0048] The embodiments described above are merely illustrative of several implementations of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this disclosure, and these all fall within the protection scope of this disclosure. Therefore, the protection scope of this patent should be determined by the appended claims. Industrial applicability

[0049] The solution provided in this application embodiment can be applied to the field of electrode laser die-cutting technology. In this application embodiment, the distance of the electrode strip is calculated from the position of the first MARK hole throughout the laser cutting process. This avoids calculation deviations caused by repeatedly defining the starting point, thereby avoiding deviations in the tab spacing of a single cut and preventing the phenomenon of cumulative cutting deviations. This reduces the scrap of electrodes and diaphragms caused by large tab misalignment, and improves the winding yield and production efficiency.

Claims

1. A method for improving the dimensional accuracy of laser die-cutting, comprising the following steps: S1. Drive the coiled material to release the electrode strip and drive the electrode strip to move in a predetermined direction; S2. Laser-cut the first MARK hole on the electrode strip, and start recording the moving distance of the electrode strip from the first MARK hole as the starting point; S3. On the electrode strip, at distances L1, L2, ..., L from the first MARK hole n-1 The positions are sequentially laser-cut to form tabs of a predetermined shape; where n is a positive integer, L1, L2, ..., L... n-1 Increase sequentially; S4. Laser die-cut a second MARK hole on the pole piece tape at a position L n from the first MARK hole, and start recording the moving distance of the pole piece tape from the second MARK hole. S5. Laser die cutting is performed on the pole piece strip in sequence at positions L1, L2, …, L n-1 , which are apart from the second MARK hole, to form the pole ear of a predetermined shape, and a third MARK hole is laser die cut at a position L n , which is apart from the second MARK hole; this is repeated until the laser die cutting of one roll of material is completed.

2. The method of improving laser die size accuracy of claim 1, wherein, In step S2, a first MARK hole is laser die-cut at a position L x from the end of the pole piece tape.

3. The method of improving laser die size accuracy of claim 1, wherein, In step S4, L n greater than L n-1 .

4. The method of improving laser die size accuracy of claim 1, wherein, The electrode tabs with predetermined shapes are laser-cut on both sides of the electrode strip along its length.

5. A device for improving the dimensional accuracy of laser die-cutting, comprising: The feeding mechanism is configured to drive the coiled material to release the electrode strip and drive the electrode strip to move in a predetermined direction; A laser die-cutting mechanism is configured to laser-die-cut the electrode strip to form electrode tabs and mark holes; and A controller connected with the conveying mechanism and the laser die-cutting mechanism, the controller being configured to control the conveying mechanism to drive the pole piece tape to move in a predetermined direction, control the laser die-cutting mechanism to laser die-cut a first MARK hole on the pole piece tape and start recording the moving distance of the pole piece tape from the first MARK hole, control the laser die-cutting mechanism to laser die-cut successively at positions L1, L2, …, Ln away from the first MARK hole to form a pole lug of a predetermined shape, and control the laser die-cutting mechanism to laser die-cut a second MARK hole at a position L away from the first MARK hole; and then control the laser die-cutting mechanism to laser die-cut successively at positions L1, L2, …, Ln away from the second MARK hole to form a pole lug of a predetermined shape, laser die-cut a third MARK hole at a position L away from the second MARK hole, and repeat the above process until the laser die-cutting of one roll of material is completed; wherein n is a positive integer, and L1, L2, …, Ln increase successively. n-1 n n-1 n n-1 n ​​​​​​ 6. The apparatus for improving the size accuracy of a laser die cut of claim 5, wherein, The device also includes an encoder electrically connected to the controller and configured to record the distance traveled by the electrode strip.

7. The apparatus for improving the size accuracy of a laser die cut of claim 5 wherein, The feeding mechanism includes an unwinding mechanism and a conveying mechanism. The unwinding mechanism is connected to the controller and is controlled by the controller to release electrode strip to the feed end of the conveying mechanism. The conveying mechanism is connected to the controller and is controlled by the controller to convey the electrode strip released by the unwinding mechanism in a predetermined direction. And / or, the device further includes a winding mechanism, which is connected to the controller and is controlled by the controller to wind up the laser-diced electrode strip at the discharge end of the conveying mechanism.

8. The apparatus for improving the size accuracy of a laser die cut of claim 5 wherein, The laser die-cutting mechanism includes two lasers, which are respectively configured to perform laser die-cutting on both sides of the electrode strip along its length to form electrode tabs and MARK holes of predetermined shapes on both sides of the electrode strip along its length.

9. A computer terminal comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, implements the steps of the method for improving the dimensional accuracy of laser die-cutting as described in any one of claims 1-4.

10. A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method for improving the dimensional accuracy of laser die-cutting as described in any one of claims 1-4.

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