Laser cutting method and laser cutting device for pole piece strip

Abstract

The present invention provides a laser cutting method and a laser cutting device for a pole piece strip. Among them, the laser cutting method for the pole piece strip includes: Step S1: Continuously convey the pole piece strip. When the cutting area of the pole piece strip moves below the laser, drive the laser to move through a driving mechanism so that the light spot formed by the laser on the pole piece strip moves synchronously with the pole piece strip; Step S2: During the synchronous movement of the light spot and the pole piece strip, the galvanometer of the laser causes the light spot to reciprocate along the width direction of the pole piece strip; Step S3: After cutting is completed, the driving mechanism drives the laser to move in the reverse direction and return to the initial position. The above laser cutting method enables the pole piece strip to be continuously conveyed without stopping during the cutting process, realizing continuous "flying cutting", which greatly improves the production efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of battery production equipment, and particularly relates to a laser cutting method and a laser cutting device for a pole piece tape. Background Art

[0002] In the production process of lithium batteries, after the pole piece tape undergoes slurry coating, drying, and roller pressing and slitting of the tab, it is necessary to cut the pole piece tape into pieces. Traditional pole piece cutting methods include circular shear slitting, die punching, and laser cutting, etc. During the pole piece cutting process, the cutting edge of the pole piece has a crucial impact on the performance of the entire battery manufacturing. The specific process requirements for pole piece cutting include burrs, dimensional accuracy, heat affected zone, edge flatness, etc. For example, if the cutting edge burr is too large, during the lamination process, the burr may pierce the separator, causing internal short circuit of the battery, resulting in large self-discharge or even fire; for another example, if the cutting dimensional accuracy is poor and it is impossible to ensure that the separator completely isolates the positive and negative pole pieces, it may also cause safety problems such as battery short circuit.

[0003] In the traditional die punching process, since the punch needs to physically contact the pole piece, after long-term use, the tool will inevitably experience wear problems, and it is easy to cause problems such as burrs on the pole piece edge and parameters such as dimensions not being met, resulting in a decrease in the quality of the pole piece finished product. In contrast, laser cutting uses a high-power and high-density laser beam to irradiate the pole piece to be cut, so that the cutting edge quickly melts and forms holes. As the laser beam moves, continuous holes form a cut seam to complete the pole piece cutting. During the cutting process, there is no physical contact between the pole piece and the cutting piece, and the overall process stability is good. Therefore, laser cutting is increasingly widely used in the cutting of lithium battery pole pieces.

[0004] In the existing pole piece laser cutting, a static cutting method is mostly used. The static cutting method means that when cutting the pole piece, the pole piece on the conveyor belt is in a static state. After the cutting is completed, the conveyor belt continues to transport the pole piece a certain distance. However, in this static laser cutting method, the tape stops during each cutting and continuous feeding is not possible, which affects the production efficiency. Moreover, the control of starting and stopping the tape directly affects the dimensional accuracy of each pole piece. Therefore, the accuracy requirements for the starting and stopping control of the tape are high. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the static cutting method is adopted in the laser cutting of battery pole pieces in the prior art, resulting in low production efficiency, so as to provide a laser cutting method and a laser cutting device for a pole piece tape.

[0006] To solve the above problems, the present invention provides a laser cutting method for a pole piece strip, including: Step S1: Continuously convey the pole piece strip. When the cutting area of the pole piece strip moves below the laser, drive the laser to move through a driving mechanism, so that the light spot formed by the laser on the pole piece strip moves synchronously with the pole piece strip; Step S2: During the synchronous movement of the light spot and the pole piece strip, the galvanometer of the laser makes the light spot reciprocate along the width direction of the pole piece strip; Step S3: After cutting is completed, the driving mechanism drives the laser to move in the reverse direction and return to the initial position.

[0007] Optionally, the part of the running track of the pole piece strip located below the laser is an arc segment, and the laser is arranged at the center of the arc segment. In Step S1, the driving mechanism drives the laser to swing.

[0008] Optionally, in Step S1, the swinging track of the laser in the moving direction of the pole piece strip includes an acceleration segment, a constant speed segment, and a deceleration segment, and the laser cuts the pole piece strip at a constant speed.

[0009] Optionally, in Step S3, the time interval between adjacent light emissions of the laser satisfies the following formula: Formula 1: where t is the time interval between adjacent light emissions of the laser, L is the length of the pole piece strip, R is the radius of the arc segment, and ω 带 is the angular velocity of the pole piece strip moving in the arc segment.

[0010] Optionally, in Step S1, the pole piece strip is attached to the arc segment by negative pressure adsorption.

[0011] Optionally, in Step S2, the light spot reciprocates along the width direction of the pole piece strip 5 to 10 times.

[0012] The present invention also provides a laser cutting device for a pole piece strip, including: a conveying mechanism adapted to convey the pole piece strip; a laser movably arranged above the conveying mechanism; a driving mechanism connected to the laser, and the driving mechanism is adapted to drive the laser to move, so that when the cutting area of the pole piece strip moves below the laser, the light spot formed by the laser on the pole piece strip moves synchronously with the pole piece strip.

[0013] Optionally, the conveying mechanism includes a first running belt, the first running belt is in an arc shape, the laser is arranged at the center of the first running belt, and the driving mechanism drives the laser to swing.

[0014] Optionally, an adsorption mechanism is arranged on the first running belt.

[0015] Optionally, the conveying mechanism further includes two second running belts, the two second running belts are respectively connected to both ends of the first running belt, and a conveying roller is arranged at the connection of the first running belt and the second running belt.

[0016] The present invention has the following advantages:

[0017] Using the technical solution of the present invention, when laser cutting the pole piece, the pole piece strip is continuously conveyed. The laser is moved by the driving mechanism, and the light spot formed by the laser emitted by it on the pole piece strip moves synchronously with the pole piece strip. At the same time, the position of the light is adjusted by the galvanometer, so that the light spot reciprocates in the width direction of the pole piece, thereby realizing the cutting of the pole piece strip. After the cutting is completed, the driving mechanism moves the laser back to its original position and prepares for the next cutting. The above laser cutting method enables the pole piece strip to be continuously conveyed without stopping during the cutting process, realizing continuous "flying cutting", which greatly improves the production efficiency. Therefore, the technical solution of the present invention solves the defect that the laser cutting of the battery pole piece in the prior art adopts a static cutting method, resulting in low production efficiency. Description of the Drawings

[0018] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 Shows a schematic flow chart of the laser cutting method of the pole piece of the present invention;

[0020] Figure 2 Shows a schematic structural diagram of the pole piece strip;

[0021] Figure 3 Shows Figure 1 A schematic diagram of the laser completing one cutting in the laser cutting method;

[0022] Figure 4 Shows Figure 1 A schematic diagram of the speed of the laser in different swinging positions in the laser cutting method; and

[0023] Figure 5 Shows a schematic structural diagram of the laser cutting device for the pole piece of the present invention.

[0024] Description of the Reference Numerals:

[0025] 10. Conveying mechanism; 11. First tape running; 12. Second tape running; 13. Conveying roller; 20. Laser; 21. Galvanometer. Detailed Embodiments

[0026] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0028] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] As Figures 1 to 3 shown, a laser cutting method for a pole piece strip of this embodiment includes:

[0031] Step S1: Continuously convey the pole piece strip. When the cutting area of the pole piece strip moves below the laser 20, drive the laser 20 to move through the driving mechanism so that the light spot formed by the laser 20 on the pole piece strip moves synchronously with the pole piece strip.

[0032] Step S2: During the synchronous movement of the light spot and the pole piece strip, the galvanometer 21 of the laser 20 makes the light spot reciprocate along the width direction of the pole piece strip.

[0033] Step S3: After cutting is completed, drive the laser 20 to move in the reverse direction through the driving mechanism and return to the initial position.

[0034] As Figure 2As shown, the electrode strip is in the shape of a long strip. For ease of explanation, the following will refer to the flow direction of the electrode strip (i.e., the length direction of the electrode strip) as the X direction, and the width direction of the electrode strip as the Y direction. The laser 20 cuts the electrode strip in the Y direction and cuts the electrode strip into multiple block-shaped electrodes. The electrode strip can be a positive electrode strip or a negative electrode strip.

[0035] In the above step S1, the continuous conveyance of the electrode strip means that the electrode strip is continuously conveyed without stopping. When the cutting area of the electrode strip, that is, Figure 2 the cutting edge in [description] passes under the laser 20, the driving mechanism drives the laser 20 to move, and makes the laser 20 move synchronously with the movement of the electrode strip in the X direction when moving at a constant speed.

[0036] It should be noted that the above "movement" includes: the laser 20 moves translationally, the laser 20 moves along a certain trajectory, or the laser 20 rotates (swings) along a certain axis.

[0037] In step S1, the light spot formed by the laser 20 on the electrode strip moves synchronously with the electrode strip in the X direction, so that a cutting edge perpendicular to the X direction is formed after cutting.

[0038] In the above step S2, the galvanometer of the laser 20 makes the light spot reciprocate on the electrode strip in the Y direction, thereby realizing the cutting of the electrode strip. Specifically, since the light spot moves synchronously with the electrode strip in the X direction, when the light spot moves in the Y direction, the electrode strip can be cut in the Y direction.

[0039] Furthermore, in the above step S3, when the laser 20 completes one cutting, the driving mechanism drives the laser 20 to move in the reverse direction to the initial position. When the next cutting area passes under the laser 20, the laser 20 executes the above steps S1 and S2 to perform the next cutting.

[0040] It should be noted that the above steps S1 and S2 are only names for the two steps and do not limit the order of the two steps.

[0041] As Figure 3 shown, in the technical solution of this embodiment, the part of the running trajectory of the electrode strip located under the laser 20 is an arc segment. The laser 20 is arranged at the center of the arc segment. In step S1, the driving mechanism drives the laser 20 to swing. Specifically, the arc segment is recessed toward the side away from the laser 20, the arc segment has a center position, and the laser 20 is arranged at the center position of the arc segment.

[0042] When the pole piece strip passes through the arc section, the pole piece strip makes a circular motion within a certain range in the arc section. For example, when the pole piece strip passes through the arc section from left to right in Figure 3 , the pole piece strip makes a counterclockwise motion within the arc section. At this time, the driving mechanism drives the laser 20 to swing counterclockwise, so that the end of the laser 20 moves synchronously with the pole piece strip in the circumferential direction.

[0043] In the above step S1, when the cutting area of the pole piece strip moves below the laser 20, that is, the cutting area of the pole piece strip moves into the arc section.

[0044] Of course, in some embodiments not shown, the running trajectory of the pole piece strip can also always be on a straight line. In this embodiment, when the cutting area of the pole piece strip passes below the laser 20, the driving mechanism drives the laser 20 to translate in the horizontal direction, so that the lower end of the laser 20 moves synchronously with the pole piece strip.

[0045] As Figure 4 shown, in the technical solution of this embodiment, in step S1, the swinging trajectory of the laser 20 towards the moving direction of the pole piece strip includes an acceleration section, a constant speed section and a deceleration section, and the laser 20 cuts the pole piece strip in the constant speed section. Specifically, those skilled in the art can understand that when the laser 20 swings, it first accelerates from rest and then maintains a constant speed. In order to ensure the quality of the cutting edge of the pole piece strip, in this embodiment, the pole piece strip is cut when the laser 20 swings to the constant speed section.

[0046] Specifically, as Figure 4 shown, the movement trajectory of the pole piece strip in the arc section includes five points: m, A, B, C and n. Correspondingly, when the laser 20 swings, the light spot formed on the pole piece strip also needs to pass through the above five points.

[0047] When the laser 20 swings, it is in a stationary state at point m, in an accelerating state from m to point A, in a constant speed state at points A, B and C, in a decelerating state from point C to point n, and finally returns to a stationary state at point n. In step S2, when the laser 20 swings within the range from point A to point C, the galvanometer 21 of the laser 20 makes the light spot reciprocate in the width direction of the pole piece strip.

[0048] Further, in the technical solution of this embodiment, in step S3, the time interval between adjacent light emissions of the laser 20 satisfies the following formula:

[0049] Formula 1:

[0050] Wherein, t is the time interval between two cuttings by the laser 20, L is the length of the pole piece strip, R is the radius of the arc segment, and W is the angular velocity of the pole piece strip moving in the arc segment.

[0051] Specifically, the above t represents the time interval between two cuts (the time from when the galvanometer 21 stops emitting light in the last moment to when it starts emitting light in the next moment), that is, the time required for the laser 20 to swing to the position where the next cutting starts after the cutting is completed. In combination with the above, it can be seen that since the laser 20 only cuts within the uniform speed of the swing, the swing trajectory of the laser 20 within the above t time interval is: point C to point n-point n, then reverse movement back to point m-point m to point A (that is, the running trajectory of the laser 20 in step S3). Within the time interval between t, the laser 20 swings from the end point of the cutting trajectory to the starting point of the next cutting. At the same time, the pole piece strip just completes the length of one pole piece strip, so the laser 20 can start cutting immediately, thereby ensuring the continuity of the cutting and not affecting the production rhythm.

[0052] Preferably, in the above step S1, the pole piece strip is made to fit with the arc segment by negative pressure adsorption. Specifically, since the arc segment is an inwardly concave trajectory, negative pressure adsorption is required to make the pole piece strip fit closely with the arc segment, so that the pole piece strip moves circumferentially in the arc segment. Specifically, a plurality of adsorption holes can be provided in the arc segment, and negative pressure is generated in the adsorption holes by a vacuum pump, so that the pole piece strip is closely attached to the surface of the arc segment.

[0053] Preferably, in step S2, the light spot moves back and forth 5 to 10 times along the width direction of the pole piece strip. Specifically, the number of reciprocating movements of the light spot can be determined according to the thickness of the pole piece strip. The reciprocating movement distance of the light spot depends on the width of the pole piece strip (i.e. Figure 3 At the same time, the laser 20 uses a low-power laser as much as possible to reduce burrs and heat-affected zones generated during the cutting process.

[0054] The above-mentioned laser cutting method of the pole piece strip has the following advantages:

[0055] 1. Ensure the cutting quality of the cutting edge

[0056] In this embodiment, a low-power laser multiple cutting method is used to reduce burrs and heat-affected zones generated during the cutting process.

[0057] 2. Prevent the cutting area from leaving the laser's 20° field of view

[0058] In this embodiment, the galvanometer 21 and the pole piece strip are kept relatively still, thereby ensuring that the laser beam is controlled within the field of view.

[0059] 3. Ensure that the laser cutting position coincides each time

[0060] In this embodiment, by synchronously rotating the galvanometer 21 and the pole piece tape, relative rest in the X-axis direction is achieved, and the laser cutting work only needs to be carried out in the Y-axis direction, simplifying the laser control difficulty.

[0061] 4. Solve the problem of possible out-of-focus of the laser during cutting

[0062] In this embodiment, by designing the galvanometer 21 to be at the center point of the arc section, it is ensured that during the rotation of the galvanometer 21, the distance from the laser spot point to the pole piece tape always remains the same, avoiding problems such as defocus. Moreover, with this design, compared to straight tape running, the rotation amplitude of the galvanometer 21 is small, greatly saving space.

[0063] As Figure 5 shown, this embodiment also provides a laser cutting device for a pole piece tape, which includes a conveying mechanism 10, a laser 20, and a driving mechanism. Among them, the conveying mechanism 10 is suitable for conveying the pole piece tape. The laser 20 is movably arranged above the conveying mechanism 10. The driving mechanism is connected to the laser 20, and the driving mechanism is suitable for driving the laser 20 to move, so that when the cutting area of the pole piece tape moves below the laser 20, the light spot formed by the laser 20 on the pole piece tape moves synchronously with the pole piece tape.

[0064] Further, during the process of the laser 20 moving synchronously with the pole piece tape, the galvanometer 21 of the laser 20 causes the light spot formed by the laser 20 on the pole piece tape to reciprocate along the width direction of the pole piece tape.

[0065] Further, the above-mentioned laser cutting device for a pole piece tape is suitable for cutting the pole piece tape by using the above-mentioned cutting method. Therefore, during the cutting process, the conveying mechanism 10 does not need to stop, and the pole piece tape is continuously conveyed, greatly improving the production efficiency.

[0066] As Figure 5 shown, in the technical solution of this embodiment, the conveying mechanism 10 includes a first tape running 11. And, the first tape running 11 is in an arc shape, and the first tape running 11 is concave in the direction away from the laser 20. The laser 20 is arranged at the center of the first tape running 11, and the driving mechanism drives the laser 20 to swing.

[0067] Preferably, an adsorption mechanism is arranged on the first tape running 11. The adsorption mechanism enables the pole piece tape to closely adhere to the first tape running 11 when the pole piece tape moves to the first tape running 11, so that the pole piece tape moves circumferentially on the surface of the first tape running 11. Further, a plurality of adsorption holes can be arranged on the first tape running 11, and the adsorption holes generate negative pressure through a vacuum pump, so that the pole piece tape closely adheres to the first tape running.

[0068] AsFigure 5 As shown, in the technical solution of this embodiment, the conveying mechanism 10 further includes two second conveyor belts 12, and the two second conveyor belts 12 are respectively connected to both ends of the first conveyor belt 11. A conveying roller 13 is provided at the connection of the first conveyor belt 11 and the second conveyor belt 12, and the conveying roller 13 conveys the pole piece strip. Specifically, the second conveyor belts 12 are both structures extending in the horizontal direction, and the two second conveyor belts 12 are respectively connected to both ends of the first conveyor belt 11. In Figure 5 the direction shown, the pole piece strip first moves to the first conveyor belt 11 through the second conveyor belt 12 on the left side. After cutting is completed, it moves from the first conveyor belt 11 to the second conveyor belt 12 on the right side.

[0069] According to the above content, using the above-mentioned pole piece strip cutting device and cutting method, the cutting process of the pole piece strip is as follows:

[0070] 1. Obtain the cutting edge length of the pole piece strip (i.e., the distances of line segments A1A2, B1B2, and C1C2 in Figure 3 ) and the spacing parameter between the two cutting edges (i.e., the length of line segment L in Figure 1 );

[0071] 2. Determine the number of laser reciprocating cuts and laser power required for each cutting edge according to process requirements;

[0072] 3. Convey the pole piece strip to be cut through the conveying mechanism 10;

[0073] 4. According to the angular velocity of the pole piece strip when moving on the first conveyor belt 11, adjust the light-emitting angular velocity of the galvanometer 21 to ensure that the speed of the laser beam in the X-axis direction is the same as the speed of the first conveyor belt 11, and the two are relatively stationary. That is, Figure 3 when the pole piece strip moves from point A to point B in

[0074] , the beam of the galvanometer 21 in the X-axis direction also rotates from point A to point B. Figure 4 5. At the same time, the laser beam reciprocates along the path in the Y-axis direction to cut the pole piece, and the cutting is completed. During the entire cutting process, the schematic diagram of the rotation angular velocity of the galvanometer 21 is as shown in

[0075] Obviously, the above embodiments are merely examples for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom still fall within the protection scope of the present invention.

Claims

1. A laser cutting method for a pole piece strip, characterized in that, comprising: Step S1: Continuously convey the pole piece strip. When the cutting area of the pole piece strip moves below the laser (20), drive the laser (20) to swing through a driving mechanism, so that the light spot formed by the laser (20) on the pole piece strip moves synchronously with the pole piece strip. Wherein, the part of the running track of the pole piece strip located below the laser (20) is an arc segment, and the laser (20) is arranged at the center of the arc segment; Step S2: During the synchronous movement of the light spot and the pole piece strip, the galvanometer (21) of the laser (20) makes the light spot reciprocate along the width direction of the pole piece strip; Step S3: After cutting is completed, the driving mechanism drives the laser (20) to move in the reverse direction and return to the initial position.

2. The laser cutting method according to claim 1, characterized in that, In the step S1, the swinging track of the laser (20) towards the moving direction of the pole piece strip includes an acceleration section, a constant speed section and a deceleration section, and the laser (20) cuts the pole piece strip in the constant speed section.

3. The laser cutting method according to claim 1, characterized in that, In the step S3, the time interval between adjacent light emissions of the laser (20) satisfies the following formula: Formula 1: ; Wherein, t is the time interval between adjacent light emissions of the laser (20), L is the length of the pole piece strip, R is the radius of the arc segment, and 带 is the angular velocity of the pole piece strip moving within the arc segment.

4. The laser cutting method according to claim 1, characterized in that, In step S1, the pole piece strip is attached to the arc segment by negative pressure adsorption.

5. The laser cutting method according to any one of claims 1 to 4, characterized in that, In the step S2, the light spot reciprocates along the width direction of the pole piece strip 5 to 10 times.

6. A laser cutting device for a pole piece strip, characterized in that, comprising: A conveying mechanism (10), adapted to convey a pole piece strip, the conveying mechanism (10) includes a first running belt (11), and the first running belt (11) is in an arc shape; A laser (20), movably arranged above the conveying mechanism (10), and the laser (20) is arranged at the center of the first running belt (11); A driving mechanism, connected to the laser (20), the driving mechanism is adapted to drive the laser (20) to swing, so that when the cutting area of the pole piece strip moves below the laser (20), the light spot formed by the laser (20) on the pole piece strip moves synchronously with the pole piece strip.

7. The laser cutting device according to claim 6, characterized in that, An adsorption mechanism is arranged on the first running belt (11).

8. The laser cutting device according to claim 6, characterized in that, The conveying mechanism (10) further includes two second running belts (12), the two second running belts (12) are respectively connected to both ends of the first running belt (11), and a conveying roller (13) is arranged at the connection of the first running belt (11) and the second running belt (12).

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