Method and system for improving laser die cutting size precision, terminal and storage medium

Abstract

The invention relates to a method and system for improving the laser die cutting size precision, a terminal and a storage medium, and the method for improving the laser die cutting size precision comprises the steps that a first MARK hole is formed in a pole piece material belt through laser die cutting, and the movement distance of the pole piece material belt is recorded with the first MARK hole as the starting point; sequentially carrying out laser die cutting on positions, which are L1, L2,..., Ln-1 away from the first MARK hole, on the pole piece material belt so as to form a pole lug with a preset shape; a second MARK hole is formed in the position, Ln away from the first MARK hole, of the pole piece material belt through laser die cutting, and the moving distance of the pole piece material belt starts to be recorded with the second MARK hole as the starting point; and sequentially performing laser die cutting at positions L1, L2,..., Ln-1 away from the second MARK hole on the pole piece material belt to form a tab with a preset shape, and performing laser die cutting at a position Ln away from the second MARK hole to form a third MARK hole. According to the invention, the phenomenon of superposition caused by cutting deviation is avoided, the scrapping of the pole piece and the diaphragm caused by large dislocation of the tabs is reduced, and the winding yield and the production efficiency are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of pole piece laser die cutting, and in particular to a method and system, a terminal and a storage medium for improving the dimensional accuracy of laser die cutting. Background Art

[0002] With the development of global renewable energy, lithium-ion batteries have gained great attention from the industry due to their high voltage, high capacity and stable material structure. 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 around the world.

[0003] Laser die-cutting is an important part of lithium battery production. It is a key process to cut the positive and negative electrode sheets into the required width and corresponding size of each tab spacing through laser cutting, so that the positive electrode sheet, separator, and negative electrode sheet can be wound into a core monomer in the subsequent winding process to ensure the alignment of the tabs. In the production process of wound battery cells, the accuracy of die-cutting dimensions is one of the keys to ensure the alignment of the tabs of the wound battery cells. The existing laser die-cutting cutting logic and schematic diagram are as follows: Figure 1 , Figure 2 As shown in the figure, when performing laser die cutting, the PLC first defines the MARK hole as the starting position and starts laser cutting from the MARK hole position to complete the first spacing L 1 After that, PLC will set this position (L away from MARK hole) 1 The position of the laser cutter is redefined as the starting position, and the encoder is used for calculation to complete the second spacing L 2 , repeating this process, the program logic is used to complete the cutting of the tab spacing, laser cutting the entire die-cutting size, and producing a complete core tape. However, in this program, since the PLC needs to redefine the starting position after completing a laser cutting, each time the laser cutting equipment needs to calculate the material tape travel distance from the redefined starting position, due to the accuracy of the laser cutting equipment, the travel distance will be deviated. After n spacings are cut, some or all of the tab spacing deviations will be superimposed, resulting in a large misalignment of the tabs on the core. After the die-cutting size is completed, when winding, the tabs on the core are misaligned, exceeding the process parameter range, so that the subsequent ultrasonic welding cannot put all the weld marks on the tabs, causing the entire core to be scrapped. Taking a certain product as an example, the total length of the positive single-core pole piece in the winding design is 21038mm, and the total length of the negative single-core pole piece is 21601mm. If the pole ears are laser cut using this program logic, once the spacing deviation superposition phenomenon occurs, a positive electrode strip with a length of 21038mm, a negative electrode strip with a length of 21601mm and a diaphragm with a length of 45192mm will have to be discharged, causing serious waste of materials and reducing the winding yield and production efficiency. Summary of the invention

[0004] Based on this, the purpose of the present invention is to provide a method and system, terminal and storage medium for improving the dimensional accuracy of laser die-cutting, so as to solve the technical problem that in the existing laser cutting method, due to the superposition of partial or complete deviations in the spacing between the pole ears, large misalignment of the wound pole ears occurs, resulting in scrapping of materials.

[0005] To achieve the above object, the present invention adopts the following technical solutions: The present invention first provides a method for improving the dimensional accuracy of laser die cutting, which comprises the following steps: S1. Drive the coil to release the pole piece and drive the pole piece to move in a predetermined direction; S2. Laser cut the first MARK hole on the pole piece strip, and start recording the moving distance of the pole piece strip from the first MARK hole as the starting point; S3. The distance from the first MARK hole on the pole piece strip is L 1 , L 2 ,…,L n-1 The positions are sequentially laser-cut to form a pole ear of a predetermined shape; wherein n is a positive integer, L 1 , L 2 ,…,L n-1 Increase successively; S4. The distance from the first MARK hole on the pole piece strip is L n The second MARK hole is cut by laser die at the position, and the moving distance of the pole piece strip is recorded starting from the second MARK hole; S5. The distance from the second MARK hole on the pole piece strip is L 1 , L 2 ,…,L n-1 The positions are laser cut in sequence to form the ear of the predetermined shape. n The third MARK hole is laser die-cut at the position; this is repeated until the laser die-cutting of a coil is completed.

[0006] As a further improvement of the above solution of the present invention, in step S2, at a distance L from the end of the electrode strip, x Laser die cut the first MARK hole at the position.

[0007] As a further improvement of the above solution of the present invention, in step S4, L n Greater than L n-1 .

[0008] As a further improvement of the above solution of the present invention, the pole lugs with a predetermined shape are laser-die-cut on both sides of the pole piece strip in the length direction.

[0009] The present invention also provides a device for improving the dimensional accuracy of laser die cutting, which comprises: A feeding mechanism, which is used to drive the coil to release the pole piece material strip and drive the pole piece material strip to move in a predetermined direction; A laser die-cutting mechanism, which is used to perform laser die-cutting on the pole piece strip to form pole ears and MARK holes; and The controller is connected to the transmission mechanism and the laser die-cutting mechanism. The controller is used to: control the transmission mechanism to drive the pole piece material strip to move in a predetermined direction, control the laser die-cutting mechanism to laser-die-cut the first MARK hole on the pole piece material strip and start recording the moving distance of the pole piece material strip from the first MARK hole as the starting point, and control the laser die-cutting mechanism to move the pole piece material strip at a distance of L from the first MARK hole. 1 , L 2 ,…,L n-1 The laser die-cutting mechanism is controlled to be at a distance of L from the first MARK hole. n The second MARK hole is cut by laser die-cutting at the position of the second MARK hole; and then the second MARK hole is used as the starting point to control the laser die-cutting mechanism to be at a distance of L from the second MARK hole on the pole piece strip. 1 , L 2 ,…,L n-1 The positions are laser die-cut in sequence to form the pole ears of the predetermined shape, and the distance from the second MARK hole L on the pole sheet strip is n The third MARK hole is cut by laser die-cutting at the position of L; this is repeated until the laser die-cutting of a coil is completed; where n is a positive integer, L 1 , L 2 ,…,L n-1 , L n Increase successively.

[0010] As a further improvement of the above solution of the present invention, the device also includes an encoder, which is electrically connected to the controller and is used to record the moving distance of the pole piece strip.

[0011] As a further improvement of the above-mentioned scheme of the present invention, the loading 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 the pole piece material strip to the feeding end of the conveying mechanism. The conveying mechanism is connected to the controller and is controlled by the controller to convey the pole piece material strip released by the unwinding mechanism in a predetermined direction.

[0012] As a further improvement of the above-mentioned solution of the present invention, the device also includes a winding mechanism, which is connected to the controller and is controlled by the controller to wind up the pole piece strip after laser die-cutting at the discharge end of the conveying mechanism.

[0013] As a further improvement of the above scheme of the present invention, the laser die-cutting mechanism includes two lasers, which are respectively used to perform laser die-cutting on both sides of the length direction of the pole piece strip to form pole ears and MARK holes of predetermined shapes on both sides of the length direction of the pole piece strip.

[0014] The present invention also proposes a computer terminal, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps of the method for improving the dimensional accuracy of laser die-cutting as described above are implemented.

[0015] The present invention further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps of the method for improving the dimensional accuracy of laser die-cutting as described above are implemented.

[0016] Compared with the prior art, the present invention has the following beneficial effects: In the entire laser cutting process, the present invention uses the position of the first MARK hole as the starting point to calculate the distance traveled by the pole piece material strip, thereby avoiding calculation deviation caused by repeated definition of the starting point, thereby avoiding deviation in the spacing between the pole ears cut out in a single time, avoiding the phenomenon of superposition of cutting deviations, reducing the scrapping of pole pieces and diaphragms caused by large misalignment of the pole ears, and improving the winding yield and production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the existing laser cutting control flow chart; Figure 2 It is a schematic diagram of the structure of the existing pole piece after laser cutting; Figure 3 A flow chart of a method for improving the dimensional accuracy of laser die cutting according to an embodiment of the present invention; Figure 4 Schematic diagram of the pole piece structure after laser cutting according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0020] First of all, it should be noted that the wound battery cell is composed of a positive electrode sheet, a negative electrode sheet and a separator. The separator is stacked between the positive electrode sheet and the negative electrode sheet to form a "sandwich" structure. When winding, the positive electrode sheet, the negative electrode sheet and the separator are rolled together, and the adjacent positive electrode sheets and negative electrode sheets are isolated by the separator to avoid short circuit. Among them, the positive electrode sheet includes a positive electrode collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode collector. The positive electrode collector not coated with the positive electrode active material layer protrudes from the positive electrode collector coated with the positive electrode active material layer. The positive electrode collector not coated with the positive electrode active material layer serves as the positive electrode ear. The negative electrode sheet includes a negative electrode collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode collector. The negative electrode collector not coated with the negative electrode active material layer protrudes from the negative electrode collector coated with the negative electrode active material layer. The negative electrode collector not coated with the negative electrode active material layer serves as the negative electrode ear. The pole sheet strip is formed into wound positive / negative pole sheets by laser cutting, and the coating area of ​​the pole sheet strip refers to the area on the current collector where the active material layer is coated, and the pole lug area of ​​the pole sheet strip refers to the area on the current collector where the active material layer is not coated, and is also the area formed by cutting.

[0021] This embodiment first proposes a device for improving the dimensional accuracy of laser die-cutting, which is used for cutting pole piece strips to form pole pieces of wound-type battery cells, including a feeding mechanism, an encoder, a laser die-cutting mechanism and a controller, and may also include a winding mechanism.

[0022] The feeding mechanism includes an unwinding mechanism and a conveying mechanism. The unwinding mechanism is used to release the pole piece material strip. In this embodiment, the unwinding mechanism can adopt the existing conventional unwinding equipment, and the unwinding mechanism mainly includes an unwinding shaft equipped with a pole piece roll, an unwinding drive unit driving the unwinding shaft to rotate to release the pole piece material strip, an unwinding correction component, and a cutter for cutting the pole piece material strip. The conveying mechanism is used to convey the pole piece material strip released by the unwinding mechanism in a predetermined direction. In this embodiment, the conveying mechanism can adopt the existing conventional conveyor line.

[0023] The encoder can accurately measure the linear displacement of the pole piece strip and convert it into digital signals, which can be used by the control system for further processing and analysis, thereby achieving precise control of motion parameters such as position.

[0024] The laser die-cutting mechanism uses a high-energy laser beam to irradiate the surface of the pole piece strip to melt and evaporate the pole piece strip, thereby forming pole ears and MARK holes. In this embodiment, the laser die-cutting mechanism includes two lasers. The two lasers are respectively used to laser die-cut the non-coated areas on both sides of the length direction of the pole piece strip to form pole ears and MARK holes of predetermined shapes on both sides of the length direction of the pole piece strip. The laser adopts an existing conventional nanosecond pulse fiber laser, a high peak nanosecond pulse fiber laser, a picosecond laser or a femtosecond laser.

[0025] The winding mechanism is used to wind up the pole piece strip that has been laser die-cut. In this embodiment, the winding mechanism can be a conventional winding device, which mainly includes a reel, a winding drive unit that drives the reel to rotate to wind up the pole piece strip, and a winding correction component.

[0026] The controller (i.e. PLC) is electrically connected to the transmission mechanism, encoder, laser die-cutting mechanism, unwinding mechanism and rewinding mechanism, and controls the transmission mechanism, laser die-cutting mechanism, unwinding mechanism and rewinding mechanism to work. Figure 3 , the specific control logic of the controller in this embodiment is as follows: S1. The controller controls the unwinding drive unit to start driving the unwinding shaft to rotate to release the pole piece material strip. One end of the pole piece material strip passes around the conveying mechanism and is fixed to the reeling shaft. Then the unwinding drive unit and the reeling drive unit are started synchronously, and the conveying mechanism drives the pole piece material strip to move in a predetermined direction.

[0027] S2. The controller controls the laser to be at a distance L from the end of the pole sheet strip. x The first MARK hole is cut by laser die at the position of the laser die. The controller controls the encoder to measure the moving distance of the pole piece strip from the first MARK hole as the starting point. The controller obtains the moving distance of the pole piece strip according to the feedback signal of the encoder. The controller compares the moving distance of the pole piece strip with the preset displacement L. 1 , L 2 ,…,L n-1 , L n Compare them respectively; where n is a positive integer, L 1 , L 2 ,…,L n-1 , L n As the L x The length shall be reasonably limited according to actual conditions.

[0028] S3. When the distance the pole piece moves is equal to L 1 When the controller controls the two lasers to perform laser die cutting on both sides of the pole piece strip, the distance between the pole piece strip and the first MARK hole L is 1 The position of the laser die cuts the ear of the predetermined shape; when the distance moved by the pole piece strip is equal to L 2 When the controller controls the two lasers to perform laser die cutting on both sides of the pole piece strip, the distance between the pole piece strip and the first MARK hole L is 2 Laser die cuts the pole ear of the predetermined shape at the position; repeat this process until the distance between the two sides of the pole piece strip and the first MARK hole L n-1 The ear of the predetermined shape is cut out by laser die-cutting.

[0029] S4. The controller controls the laser to be at a distance L from the first MARK hole on the pole piece strip. nThe controller controls the encoder to start measuring the moving distance of the pole piece strip from the second MARK hole as the starting point. The controller obtains the moving distance of the pole piece strip according to the feedback signal of the encoder. The controller compares the moving distance of the pole piece strip with the preset displacement L. 1 , L 2 ,…,L n-1 Compare them separately.

[0030] S5. When the distance the pole piece moves is equal to L 1 When the controller controls the two lasers to perform laser die cutting on both sides of the pole piece strip, the distance between the second MARK hole and the pole piece strip is L. 1 The position of the laser die cuts the ear of the predetermined shape; when the distance moved by the pole piece strip is equal to L 2 When the controller controls the two lasers to perform laser die cutting on both sides of the pole piece strip, the distance between the second MARK hole and the pole piece strip is L. 2 The predetermined shape of the pole ear is laser-cut at the position; this is repeated until the distance between the two sides of the pole piece strip and the second MARK hole L n-1 The laser die-cutting is performed at the position of the coil to form a predetermined shape of the pole ear. This process is repeated until the laser die-cutting of a coil is completed.

[0031] The pole piece strip after laser die cutting in this embodiment is as follows Figure 4 As shown, this embodiment optimizes the laser die-cutting program to avoid the superposition of some or all of the tab spacing deviations due to the deviation in the tab spacing each time the laser cuts, which leads to the scrapping of the entire positive / negative electrode tape and the diaphragm in the winding process, thereby greatly reducing the scrap rate of winding, improving the utilization rate and yield of winding materials, and saving production materials.

[0032] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0033] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for improving the dimensional accuracy of laser die cutting, characterized in that: It includes the following steps: S1. Drive the coil to release the pole piece and drive the pole piece to move in a predetermined direction; S2. Laser cut the first MARK hole on the pole piece strip, and start recording the moving distance of the pole piece strip from the first MARK hole as the starting point; S3. The distance from the first MARK hole on the pole piece strip is L1, L2, ..., L n-1 The positions are sequentially laser-cut to form a pole ear of a predetermined shape; wherein n is a positive integer, L1, L2, ..., L n-1 Increase successively; S4. The distance from the first MARK hole on the pole piece strip is L n The second MARK hole is cut by laser die at the position, and the moving distance of the pole piece strip is recorded starting from the second MARK hole; S5. The distance from the second MARK hole on the pole piece strip is L1, L2, ..., L n-1 The positions are laser cut in sequence to form the ear of the predetermined shape. n The third MARK hole is laser die-cut at the position; this is repeated until the laser die-cutting of a coil is completed.

2. The method for improving the dimensional accuracy of laser die cutting according to claim 1, characterized in that: In step S2, at a distance L from the end of the electrode strip, x Laser die cut the first MARK hole at the position.

3. The method for improving the dimensional accuracy of laser die cutting according to claim 1, characterized in that: In step S4, L n Greater than L n-1 .

4. The method for improving the dimensional accuracy of laser die cutting according to claim 1, characterized in that: The pole lugs with a predetermined shape are laser-cut on both sides of the pole sheet strip in the length direction.

5. A device for improving the dimensional accuracy of laser die cutting, characterized in that: It includes: A feeding mechanism, which is used to drive the coil to release the pole piece material strip and drive the pole piece material strip to move in a predetermined direction; A laser die-cutting mechanism, which is used to perform laser die-cutting on the pole piece strip to form pole ears and MARK holes; and The controller is connected to the transmission mechanism and the laser die-cutting mechanism. The controller is used to: control the transmission mechanism to drive the pole piece material strip to move in a predetermined direction, control the laser die-cutting mechanism to laser-die-cut the first MARK hole on the pole piece material strip and start recording the moving distance of the pole piece material strip with the first MARK hole as the starting point, and control the laser die-cutting mechanism to move at a distance of L1, L2, ..., L n-1 The laser die-cutting mechanism is controlled to be at a distance of L from the first MARK hole. n The second MARK hole is cut out by laser die-cutting at the position of the second MARK hole; and then the second MARK hole is used as the starting point to control the laser die-cutting mechanism to be L1, L2, ..., L on the pole piece strip at a distance from the second MARK hole. n-1 The positions are laser die-cut in sequence to form the pole ears of the predetermined shape, and the distance from the second MARK hole L on the pole sheet strip is n The third MARK hole is cut by laser die-cutting at the position of L1; this is repeated until the laser die-cutting of a coil is completed; where n is a positive integer, L1, L2, ..., L n-1 , L n Increase successively.

6. The device for improving the dimensional accuracy of laser die cutting according to claim 5, characterized in that: The device also includes an encoder, which is electrically connected to the controller and is used to record the moving distance of the pole piece strip.

7. The device for improving the dimensional accuracy of laser die cutting according to claim 5, characterized in that: The feeding mechanism includes an unwinding mechanism and a conveying mechanism, wherein the unwinding mechanism is connected to the controller and is controlled by the controller to release the pole piece material strip to the feeding end of the conveying mechanism, and the conveying mechanism is connected to the controller and is controlled by the controller to convey the pole piece material strip released by the unwinding mechanism in a predetermined direction; and / or, the device also includes a winding mechanism, which is connected to the controller and is controlled by the controller to wind up the pole piece material strip after laser die-cutting at the discharging end of the conveying mechanism.

8. The device for improving the dimensional accuracy of laser die cutting according to claim 5, characterized in that: The laser die-cutting mechanism includes two lasers, and the two lasers are respectively used to perform laser die-cutting on both sides of the length direction of the pole piece strip to form pole ears and MARK holes of predetermined shapes on both sides of the length direction of the pole piece strip.

9. A computer terminal comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of the method for improving the dimensional accuracy of laser die-cutting as described in any one of claims 1 to 4 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method for improving the dimensional accuracy of laser die-cutting as described in any one of claims 1 to 4 are implemented.

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