Laser cutting device, system and method

Abstract

A laser cutting device, system and method. The laser cutting device comprises a first laser emitting module, a second laser emitting module, and a beam combining module; the first laser emitting module is configured to emit a first laser beam; the second laser emitting module is configured to emit a second laser beam; and the beam combining module is arranged at light-exit sides of the first laser emitting module and the second laser emitting module, and is configured to receive and combine the first laser beam (11) and the second laser beam (12) so as to form a combined beam in which the second laser beam (12) is distributed around the first laser beam (11).

Description

A laser cutting apparatus, system and method

[0001] Cross-reference to related applications

[0002] This disclosure claims priority to Chinese Patent Application No. 202410910626.X, filed on July 9, 2024, entitled "A Laser Cutting Apparatus, System and Method", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure belongs to the field of battery technology, and specifically relates to a laser cutting device, system and method. Background Technology

[0004] Electrode cutting is a critical process in lithium battery production, and the quality of the cut electrodes directly affects the overall quality of the lithium battery. Electrode cutting typically employs laser cutting technology. This technology uses a high-power, high-density laser beam to irradiate the electrode, causing it to rapidly melt, vaporize, ablate, or reach its ignition point, forming holes. As the laser beam and the electrode move relative to each other, the holes continuously form very narrow kerfs, thus completing the electrode cutting process.

[0005] However, since electrodes typically consist of an aluminum foil layer and coating layers on both sides of the aluminum foil layer, the aluminum foil layer has a very high melting point and is difficult to vaporize directly. During laser cutting, some of the aluminum foil layer liquefies and sputters onto the surface of the coating layer, flowing and carrying the coating material, thus forming large molten beads that affect the quality of the electrode. Summary of the Invention

[0006] This disclosure aims to provide a laser cutting apparatus, system, and method to solve the problem of large molten beads being generated during existing laser cutting processes, which affects the quality of the electrode sheet.

[0007] To solve the above-mentioned technical problems, this disclosure is implemented as follows:

[0008] In a first aspect, this disclosure discloses a laser cutting device for use on an item to be cut, the laser cutting device comprising: a first laser emitting module, a second laser emitting module, and a beam combining module;

[0009] The first laser emitting module is used to emit a first laser beam;

[0010] The second laser emitting module is used to emit a second laser beam;

[0011] The beam combining module is disposed on the light-emitting side of the first laser emitting module and the second laser emitting module. The beam combining module is used to receive and combine the first laser beam and the second laser beam to form a composite beam in which the second laser beam is distributed around the first laser beam.

[0012] Optionally, the first laser beam and the second laser beam have different wavelengths.

[0013] Optionally, the wavelength of the first laser beam is shorter than the wavelength of the second laser beam.

[0014] Optionally, the first laser beam irradiates the surface of the object to be cut to form a first spot, and the second laser beam irradiates the surface of the object to be cut to form a second spot;

[0015] The first light spot is circular, and the second light spot is ring-shaped.

[0016] Optionally, the first laser emitting module includes: a first laser generator and a first beam expander;

[0017] The first laser generator is used to generate the first laser beam;

[0018] The first beam expander is disposed on the light-emitting side of the first laser generator, and the first beam expander is used to expand the diameter of the first laser beam.

[0019] Optionally, the first laser emitting module further includes a first reflector and a second reflector, which are respectively disposed on the light-incident side and the light-outcident side of the first beam expander. The first reflector and the second reflector are used to change the optical axis direction of the first laser beam.

[0020] Optionally, the second laser emitting module includes: a second laser generator, a second beam expander, an axonocone prism assembly, and a collimating lens;

[0021] The second laser generator is used to generate the second laser beam;

[0022] The second beam expander is disposed on the light-emitting side of the second laser generator, and the second beam expander is used to increase the diameter of the second laser beam;

[0023] The axial cone prism assembly is disposed on the light-emitting side of the second beam expander, and the axial cone prism assembly is used to change the shape of the second laser beam;

[0024] The collimating lens is disposed on the light-emitting side of the axial cone prism assembly, and the collimating lens is used to change the divergence angle of the second laser beam.

[0025] Optionally, the axial cone prism assembly includes: a first axial cone prism and a second axial cone prism;

[0026] The first axial cone prism and the second axial cone prism are symmetrically arranged along the optical axis of the second laser beam, with the first axial cone prism being close to the second beam expander.

[0027] The first axial cone prism has a first focal point located on the light-emitting side of the first axial cone prism, and the second axial cone prism has a second focal point located on the light-incident side of the second axial cone prism, and the second focal point coincides with the first focal point.

[0028] Optionally, the base angles of the first axial cone prism and the second axial cone prism both satisfy: 1.5°-3°.

[0029] Optionally, the first laser emitting module further includes a third reflector, which is disposed between the second laser generator and the second beam expander, and is used to change the optical axis direction of the second laser beam.

[0030] Optionally, the beam combining module includes a beam combining mirror;

[0031] From the center of the beam combiner to the edge of the beam combiner, the beam combiner includes a transmission area and a reflection area distributed sequentially. The transmission area is used to transmit the first laser beam, and the reflection area is used to reflect the second laser beam, so that the optical axes of the first laser beam and the second laser beam coincide.

[0032] Optionally, the laser cutting device further includes a scanning and focusing module;

[0033] The scanning and focusing module is located on the light-emitting side of the beam combining module and above the item to be cut. The scanning and focusing module is used to apply the composite beam to the surface of the item to be cut in order to achieve cutting.

[0034] Optionally, the scanning focusing module includes a galvanometer and a field lens connected to each other, with the galvanometer positioned close to the beam combining module;

[0035] The galvanometer is used to receive and control the composite beam to scan along a preset trajectory;

[0036] The field lens is used to focus the composite beam onto the surface of the object to be cut.

[0037] Secondly, this disclosure discloses a laser cutting system, which includes: a conveying mechanism, an air knife device, and the aforementioned laser cutting apparatus;

[0038] The conveying mechanism is used to convey items to be cut;

[0039] The laser cutting device is positioned above the conveying mechanism. The laser cutting device is used to emit and control a composite beam to scan the item to be cut back and forth along a preset trajectory, so that the item to be cut forms a cut surface.

[0040] The air knife device is positioned above the conveying mechanism and is used to blow away the cut surface.

[0041] Optionally, the conveying mechanism includes a conveying plane for placing the item to be cut;

[0042] The air outlet direction of the air knife device is a first direction, which is set at an angle to the conveying plane.

[0043] Optionally, the angle between the first direction and the conveying plane is 0°-25°.

[0044] Optionally, the conveying mechanism includes a conveying plane for placing the item to be cut;

[0045] The optical axis of the composite beam is a second direction, which is perpendicular to the delivery plane.

[0046] Thirdly, this disclosure discloses a laser cutting method using the laser cutting system described in any of the above claims, the laser cutting method comprising:

[0047] The control conveyor mechanism transports the items to be cut to the bottom of the laser cutting device;

[0048] The laser cutting device is controlled to emit a composite beam and scan the object to be cut back and forth along a preset trajectory, so that the object to be cut forms a cutting surface;

[0049] Control the air knife device to blow and sweep the cut surface.

[0050] Optionally, the scanning speed of the laser cutting device is 17000mm / s-19000mm / s.

[0051] Optionally, the wavelength of the first laser beam is 280nm-600nm;

[0052] And / or, the pulse width of the first laser beam is 1ns-50ns;

[0053] And / or, the energy of the first laser beam is 100W-500W.

[0054] Optionally, the wavelength of the second laser beam is 900nm-10600nm;

[0055] And / or, the pulse width of the second laser beam is 1ns-300ns;

[0056] And / or, the energy of the second laser beam is 300W-1000W.

[0057] Optionally, the laser cutting device performs 5 to 12 scans.

[0058] Optionally, the outlet air pressure of the air knife device is 0.1 kPa-0.3 kPa.

[0059] In this embodiment, a first laser emitting module, a second laser emitting module, and a beam combining module are provided. The beam combining module can receive and combine the first and second laser beams emitted by the first and second laser emitting modules, thereby forming a composite beam in which the second laser beam surrounds the first laser beam. Thus, during electrode cutting, the second laser beam located on the outer side of the composite beam can preheat the electrode, reducing the temperature rise required for the first laser beam located on the inner side of the composite beam to cut the electrode, thereby shortening the time required for electrode vaporization. This reduces the cutting time and number of cuts, improving electrode cutting efficiency. More importantly, it increases the vaporization rate of the aluminum foil layer, reducing the chance of aluminum foil layer liquefaction sputtering, effectively suppressing the formation of molten beads, and improving electrode quality.

[0060] Additional aspects and advantages of this disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this disclosure. Attached Figure Description

[0061] The above and / or additional aspects and advantages of this disclosure will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0062] Figure 1 is a partial structural schematic diagram of a laser cutting device provided in an embodiment of this disclosure;

[0063] Figure 2 is a second partial structural schematic diagram of a laser cutting device provided in an embodiment of this disclosure;

[0064] Figure 3 is a schematic diagram of the structure of a composite spot generated by a laser cutting device according to an embodiment of this disclosure;

[0065] Figure 4 is a schematic diagram of the structure of the electrode in the prior art;

[0066] Figure 5 is a schematic diagram of the structure of the electrode sheet after cutting in the prior art;

[0067] Figure 6 is a schematic diagram of the structure of the cut electrode sheet provided in an embodiment of this disclosure;

[0068] Figure 7 is a schematic diagram of the structure of the axial cone prism assembly provided in the embodiment of this disclosure.

[0069] Reference numerals: 1. First laser generator, 2. First reflector, 3. First beam expander, 4. Second reflector, 5. Second laser generator, 6. Third reflector, 7. Second beam expander, 8. Axicon prism assembly, 81. First axial conical prism, 82. Second axial conical prism, 9. Collimating lens, 10. Beam combiner, 11. First laser beam, 1101. First spot, 12. Second laser beam, 1201. Second spot, 13. Galvanometer, 14. Field mirror, 15. Air knife device, 16. Electrode, 1601. Aluminum foil layer, 1602. Coating layer, 1603. Fused bead, X. First direction, Y. Second direction. Detailed Implementation

[0070] Embodiments of this disclosure will now be described in detail, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this disclosure, and should not be construed as limiting this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are within the scope of protection of this disclosure.

[0071] The terms "first" and "second" in this disclosure may explicitly or implicitly include one or more of the features. In the description of this disclosure, unless otherwise stated, "a plurality of" means two or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0072] In the description of this disclosure, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.

[0073] In the description of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure based on the specific circumstances.

[0074] Referring to Figure 4, a schematic diagram of the structure of the electrode sheet in the prior art is shown. Referring to Figure 5, a schematic diagram of the structure of the electrode sheet after cutting in the prior art is shown.

[0075] As shown in Figure 4, taking electrode 16 as an example, electrode 16 includes an aluminum foil layer 1601 and a coating layer 1602 disposed on both sides of the aluminum foil layer 1601. The coating layer 1602 is composed of lithium iron phosphate particles and adhesive. The melting point of the aluminum foil layer 1601 is above 2000℃, the melting point of the coating layer 1602 is 300-400℃, and the melting point of the adhesive in the coating layer 1602 is 180-200℃. Existing laser cutting technology is usually a nanosecond laser cutter. The laser beam emitted by the nanosecond laser cutter forms a circular spot on the surface of electrode 16, with a Gaussian energy distribution, i.e., strong energy in the center and weaker energy in the outer ring. When cutting the electrode 16 using a nanosecond laser cutter, the aluminum foil layer 1601 has a high melting point and is difficult to vaporize directly. This causes some of the aluminum foil layer 1601 to liquefy and sputter onto the surface of the coating layer 1602, flowing and entraining lithium iron phosphate particles. As a result, large molten beads 1603 are formed on the upper surface of the electrode 16, i.e., the surface near the laser cutter, and on the upper side of the cut surface of the electrode 16, as shown in Figure 5. In subsequent stacking processes, the molten beads 1603 located on the surface of the electrode 16 and the cut surface can damage or even puncture the separator, affecting the quality of the battery.

[0076] This disclosure provides a laser cutting apparatus, which will be described in detail below with reference to the accompanying drawings.

[0077] Referring to Figures 1 and 2, a partial structural schematic diagram of a laser cutting device provided in an embodiment of the present disclosure is shown; referring to Figure 3, a structural schematic diagram of a composite light spot generated by a laser cutting device provided in an embodiment of the present disclosure is shown; referring to Figure 6, a structural schematic diagram of the cut electrode sheet provided in an embodiment of the present disclosure is shown; referring to Figure 7, a structural schematic diagram of the axial cone prism assembly provided in an embodiment of the present disclosure is shown.

[0078] As shown in Figures 1 and 2, this disclosure provides a laser cutting device for use on items to be cut. The laser cutting device includes: a first laser emitting module, a second laser emitting module, and a beam combining module. The first laser emitting module is used to emit a first laser beam 11. The second laser emitting module is used to emit a second laser beam 12. The beam combining module is disposed on the light-emitting side of the first laser emitting module and the second laser emitting module. The beam combining module is used to receive and combine the first laser beam 11 and the second laser beam 12 to form a composite beam in which the second laser beam 12 is distributed around the first laser beam 11.

[0079] In this embodiment, a first laser emitting module, a second laser emitting module, and a beam combining module are provided. The beam combining module can receive and combine the first laser beam 11 and the second laser beam 12 emitted by the first and second laser emitting modules, thereby forming a composite beam in which the second laser beam 12 surrounds the first laser beam 11. Thus, during the cutting of the electrode 16, the second laser beam 12 located on the outer side of the composite beam can preheat the electrode 16, reducing the temperature rise required by the first laser beam 11 located on the inner side of the composite beam when cutting the electrode 16, thereby shortening the time required for the electrode 16 to vaporize. On the one hand, this reduces the cutting time and number of cuts, which is beneficial to improving the cutting efficiency of the electrode 16. More importantly, it can increase the vaporization rate of the aluminum foil layer 1601, reducing the chance of liquefaction sputtering of the aluminum foil layer 1601, thereby effectively suppressing the formation of molten beads 1603 and improving the quality of the electrode 16.

[0080] Optionally, the wavelengths of the first laser beam 11 and the second laser beam 12 are different.

[0081] In this embodiment of the disclosure, since the wavelengths of the first laser beam 11 and the second laser beam 12 are different, different materials of the electrode 16 can be adapted to increase the absorption rate of the material to the laser and improve the energy conversion efficiency.

[0082] It should be noted that the embodiments disclosed herein are based on the case where the object to be cut is an electrode sheet 16. However, it is understood that the object to be cut includes, but is not limited to, the electrode sheet 16. Those skilled in the art can use the laser cutting device provided in this disclosure to cut other thin plates as needed, and this is not limited here. The wavelengths of the first laser beam 11 and the second laser beam 12 can range from 280nm to 10600nm, and those skilled in the art can select them based on factors such as the absorption rate of the laser by the object to be cut. Since the second laser beam 12, located on the outer side, mainly functions to adapt to the lower melting point of the coating layer 1602 and preheat the electrode sheet 16, while the first laser beam 11, located on the inner side, mainly functions to adapt to the higher melting point of the aluminum foil layer 1601 and cut the electrode sheet 16, the energy released by the first laser beam 11 should be higher than the energy released by the second laser beam 12. Based on this, in this embodiment, the wavelength of the first laser beam 11 is smaller than the wavelength of the second laser beam 12. Further, the wavelength of the first laser beam 11 is 280nm-600nm, and the wavelength of the second laser beam 12 is 900nm-10600nm. For example, the wavelength of the first laser beam 11 can be 280nm, 532nm, 600nm, or other wavelengths; the wavelength of the second laser beam 12 can be 900nm, 1064nm, 10600nm, or other wavelengths, without limitation. Those skilled in the art can adjust the wavelength according to the material of the item to be cut. In one embodiment, taking the electrode 16 as an example, the second laser beam 12 can use infrared light with a wavelength of 1064nm to adapt to the coating layer 1602 of the electrode 16, achieving preheating of the electrode 16; the first laser beam 11 can use green light with a wavelength of 532nm to adapt to the aluminum foil layer 1601 of the electrode 16, achieving cutting of the electrode 16. Furthermore, the first laser beam 11 and the second laser beam 12 are distributed at a 90° angle before merging.

[0083] In some optional embodiments of this disclosure, a first laser beam 11 irradiates the surface of the object to be cut to form a first light spot 1101, and a second laser beam 12 irradiates the surface of the object to be cut to form a second light spot 1201; the first light spot 1101 is circular, and the second light spot 1201 is annular. Thus, when the composite beam irradiates the surface of the electrode 16, a composite light spot as shown in FIG3 can be formed. The composite light spot acts on the surface of the electrode 16. During the movement of the composite light spot relative to the electrode 16, the second light spot 1201 located on the outer side can preheat the electrode 16, thereby reducing the temperature rise required by the first light spot 1101 located on the inner side when cutting the electrode 16, shortening the time required for the electrode 16 to vaporize, thus reducing the cutting time and number of cuts, and improving the cutting efficiency of the electrode 16. Furthermore, when molten beads 1603 are inevitably generated during the cutting process of the electrode 16, the second spot 1201 located on the outer side can also bombard and heat the molten beads 1603 sputtered onto the upper surface of the electrode 16 and the upper side of the cut surface. On the one hand, large molten beads 1603 can be broken into smaller molten beads 1603, so that when the size of the molten beads 1603 is smaller than the thickness of the diaphragm, it will not puncture the diaphragm. On the other hand, it can make the flow of the molten beads 1603 smoother, thereby effectively avoiding the problem of the diaphragm being easily punctured when the molten beads 1603 have sharp corners, which is beneficial to improving the quality of the electrode 16.

[0084] In practical applications, taking the cutting of a 150μm electrode 16 as an example, using existing nanosecond laser cutters with a laser beam energy of 500W, the number of cuts required to complete the cut is generally more than 12. Using the laser cutting device disclosed herein, due to its preheating function, material vaporization can be achieved in a shorter time. Testing shows that the number of cuts can be adaptively reduced to 5-12, thereby effectively improving the cutting efficiency of the laser cutting device.

[0085] In some optional embodiments of this disclosure, the first laser emitting module includes: a first laser generator 1 and a first beam expander 3; the first laser generator 1 is used to generate a first laser beam 11; the first beam expander 3 is disposed on the light-emitting side of the first laser generator 1, and the first beam expander 3 is used to expand the diameter of the first laser beam 11. In this way, by setting the first beam expander 3, the diameter of the first laser beam 11 can be expanded, thereby obtaining a first light spot 1101 of a suitable size, so that the object to be cut can ultimately form a kerf of suitable width.

[0086] In some optional embodiments of this disclosure, the first laser emitting module further includes a first reflecting mirror 2 and a second reflecting mirror 4. The first reflecting mirror 2 and the second reflecting mirror 4 are respectively disposed on the light-incident side and the light-outcident side of the first beam expander 3. The first reflecting mirror 2 and the second reflecting mirror 4 are used to change the optical axis direction of the first laser beam 11. In this way, by setting the first reflecting mirror 2 and the second reflecting mirror 4, the optical axis direction of the first laser beam 11 can be changed, thereby optimizing the arrangement of various components in the optical path, making the structure of the laser cutting device more compact, and facilitating the miniaturization of the laser cutting device.

[0087] It should be noted that the embodiments disclosed herein do not limit the angle between the light-incident and light-excising sides of the first laser beam 11 of the first reflector 2, nor the angle between the light-incident and light-excising sides of the first laser beam 11 of the second reflector 4. That is, the embodiments disclosed herein do not limit the angle by which the optical axis direction of the first laser beam 11 changes after reflection by the first reflector 2 and the second reflector 4. Those skilled in the art can adjust this according to the positions of the components in the optical path. In one embodiment, as shown in FIG1, the angle between the light-incident and light-excising sides of the first laser beam 11 of the first reflector 2 and the second reflector 4 is 90°. That is, after reflection by the first reflector 2 and the second reflector 4, the optical axis direction of the first laser beam 11 changes by 90°. This allows for a more compact structure of the laser cutting device while avoiding interference between the first laser beam 11 and the second laser beam 12, which is beneficial for the miniaturization of the laser cutting device.

[0088] In some optional embodiments of this disclosure, the second laser emitting module includes: a second laser generator 5, a second beam expander 7, an axial cone prism assembly 8, and a collimating lens 9; the second laser generator 5 is used to generate a second laser beam 12; the second beam expander 7 is disposed on the light-emitting side of the second laser generator 5, and the second beam expander 7 is used to enlarge the diameter of the second laser beam 12; the axial cone prism assembly 8 is disposed on the light-emitting side of the second beam expander 7, and the axial cone prism assembly 8 is used to change the shape of the second laser beam 12; the collimating lens 9 is disposed on the light-emitting side of the axial cone prism assembly 8, and the collimating lens 9 is used to change the divergence angle of the second laser beam 12.

[0089] In this embodiment, the diameter of the second laser beam 12 can be increased by setting the second beam expander 7, thereby obtaining a second light spot 1201 of suitable size so that the object to be cut can ultimately form a kerf of suitable width. By setting the axial cone prism assembly 8 on the light-emitting side of the second beam expander 7, the shape of the second laser beam 12 can be changed so that the second laser beam 12 irradiates the surface of the object to be cut to form a ring-shaped second light spot 1201, so as to combine with the first light spot 1101 to form a composite light spot of the desired shape. Since the second laser beam 12 has a certain divergence angle after passing through the axial cone prism assembly 8, a collimating lens 9 can be set on the light-emitting side of the axial cone prism assembly 8 to obtain a collimated second laser beam 12, so as to combine with the first laser beam 11.

[0090] In some optional embodiments of this disclosure, as shown in FIG7, the axial cone prism assembly 8 includes: a first axial cone prism 81 and a second axial cone prism 82; the first axial cone prism 81 and the second axial cone prism 82 are symmetrically arranged along the optical axis of the second laser beam 12, and the first axial cone prism 81 is close to the second beam expander 7; the first axial cone prism 81 has a first focal point located on the light-emitting side of the first axial cone prism 81, and the second axial cone prism 82 has a second focal point located on the light-incident side of the second axial cone prism 82, and the second focal point coincides with the first focal point.

[0091] In this embodiment, a first axial conical prism 81 and a second axial conical prism 82 are symmetrically arranged. Thus, the second laser beam 12 with a circular spot first passes through the first axial conical prism 81, where it undergoes initial refraction and focusing at the conical surface of the first axial conical prism 81. Then, it passes through the second axial conical prism 82, where it undergoes further refraction and focusing at the conical surface of the second axial conical prism 82. This transforms the circular spot into an annular spot approximating a Bessel function. In other words, the shape of the second laser beam 12 can be changed simply by symmetrically arranging two axial conical prisms. This structure for changing the spot shape is simple and helps to simplify the structure of the second laser emission module.

[0092] It should be noted that the specifications of the first-axis conical prism 81 and the second-axis conical prism 82 are not limited in this embodiment, and those skilled in the art can adjust them as needed. In one embodiment, the specifications of the first-axis conical prism 81 and the second-axis conical prism 82 are the same, and the base angle α of both the first-axis conical prism 81 and the second-axis conical prism 82 satisfies 1.5°-3°. Thus, when the base angle satisfies 1.5°-3°, a ring-shaped light spot of suitable size and shape can be obtained, so as to better recombine with the circular light spot formed by the first laser beam 11 and avoid mutual interference between the two. For example, the base angle α can be 1.5°, 2°, 2.5°, 3° or other angles, which are not limited here, and those skilled in the art can adjust them according to actual needs.

[0093] In some optional embodiments of this disclosure, the second laser emitting module further includes a third reflector 6, which is disposed between the second laser generator 5 and the second beam expander 7. The third reflector 6 is used to change the optical axis direction of the second laser beam 12. In this way, by setting the third reflector 6, the optical axis direction of the second laser beam 12 can be changed, thereby optimizing the arrangement of various components in the optical path, making the structure of the laser cutting device more compact, and facilitating the miniaturization of the laser cutting device.

[0094] It should be noted that the present invention does not limit the angle between the light-incident side and the light-outcident side of the second laser beam 12 of the third reflector 6. That is, the present invention does not limit the angle by which the optical axis direction of the second laser beam 12 changes after reflection by the third reflector 6. Those skilled in the art can adjust it according to the position of each component in the optical path. In one embodiment, as shown in FIG1, the angle between the light-incident side and the light-outcident side of the second laser beam 12 of the third reflector 6 is 90°. That is, the optical axis direction of the second laser beam 12 changes by 90° after reflection by the third reflector 6. In this way, while avoiding interference between the first laser beam 11 and the second laser beam 12, the structure of the laser cutting device can be made more compact, which is beneficial to the miniaturization of the laser cutting device.

[0095] In practical applications, the first laser generator 1, the second laser generator 2, the first reflector 2, the second reflector 4, and the third reflector 6 can all be existing products. The first beam expander 3, the second beam expander 7, the first axial conical prism 81, the second axial conical prism 82, and the collimating lens 9 can be customized as needed, such as optical simulation structures, and can only be put into use after assembly and debugging with other components. Since the cutting difficulty varies for different materials, taking the electrode 16 as an example, the energy and pulse width of the first laser beam 11 and the second laser beam 12 emitted by the first laser generator 1 and the second laser generator 5 can be adjusted to adapt to the aluminum foil layer 1601 and the dressing layer 1602 of the electrode 16. In one embodiment, the energy range of the first laser beam can be 100W-500W, the pulse width can be 1ns-50ns, and the wavelength can be 532±10nm; the energy range of the second laser beam can be 300W-1000W, the pulse width can be 1ns-300ns, and the wavelength can be 1064±10nm. Furthermore, this disclosure does not limit the magnification factor of the first beam expander 3 and the second beam expander 7. Those skilled in the art can adjust them according to actual needs. In one embodiment, the magnification factor of the first beam expander 3 and the second beam expander 7 is 2-5, that is, the diameter of the first laser beam 11 on the light-emitting side of the first beam expander 3 is 2-5 times the diameter of the first laser beam 11 on the light-incident side, and the diameter of the second laser beam 12 on the light-emitting side of the second beam expander 7 is 2-5 times the diameter of the second laser beam 12 on the light-incident side.

[0096] In some optional embodiments of this disclosure, the beam combining module includes a beam combining mirror 10; from the center of the beam combining mirror 10 to the edge of the beam combining mirror 10, the beam combining mirror 10 includes a transmission area and a reflection area distributed sequentially, the transmission area is used to transmit a first laser beam 11, and the reflection area is used to reflect a second laser beam 12, so that the optical axes of the first laser beam 11 and the second laser beam 12 coincide.

[0097] In this embodiment of the present disclosure, by setting a beam combiner 10, the first laser beam 11 and the second laser beam 12 can be combined to form a composite beam with the optical axis overlapping. In this way, when the composite beam acts on the surface of the object to be cut, a composite light spot as shown in Figure 3 can be formed.

[0098] It should be noted that the beam combiner 10 of this embodiment can be customized as needed, such as with optical simulation structures, and can only be put into use after assembly and debugging with other components. In practical applications, the beam combiner 10 includes two sides arranged opposite to each other, one side being located near the second reflecting mirror 4 and the other side being located near the collimating lens 9. The side of the beam combiner 10 near the collimating lens 9 has a high-reflectivity film in its reflection area that allows the second laser beam 12 to be reflected, and both sides of the beam combiner 10 have high-transmittance films in their transmission areas that allow the first laser beam 11 to be transmitted.

[0099] In some optional embodiments of this disclosure, the laser cutting apparatus further includes a scanning and focusing module. The scanning and focusing module is disposed on the light-emitting side of the beam combining module and located above the object to be cut. The scanning and focusing module is used to apply the composite beam to the surface of the object to achieve cutting. Thus, the first laser beam 11 and the second laser beam 12, i.e., the composite beam, are focused by the scanning and focusing module to form a cone-shaped beam as shown in Figure 2. By placing the object to be cut at the focal point and moving the composite beam, a smaller kerf can be obtained, achieving a better cutting effect.

[0100] In practical applications, the scanning and focusing module can be a combination of galvanometer 13 and field lens 14, or a combination of a moving module and a cutting head. No limitation is made here, and those skilled in the art can choose according to actual needs. In one embodiment, the scanning and focusing module includes an interconnected galvanometer 13 and field lens 14, with the galvanometer 13 positioned close to the beam combining module. The galvanometer 13 receives and controls the composite beam to scan along a preset trajectory; the field lens 14 focuses the composite beam onto the surface of the object to be cut. Specifically, the field lens 14 is positioned close to the object to be cut, and the galvanometer 13 is fixedly connected to the side of the field lens 14 facing away from the object. Both the galvanometer 13 and the field lens 14 can be customized as needed, such as with optical simulation structures, and can only be used after assembly and debugging with other components. It should be noted that the preset trajectory refers to the movement trajectory of the composite beam set before cutting, by which a specific shaped cut is obtained.

[0101] In summary, the laser cutting apparatus provided in this disclosure has at least the following advantages:

[0102] In this embodiment, a first laser emitting module, a second laser emitting module, and a beam combining module are provided. The beam combining module can receive and combine the first and second laser beams emitted by the first and second laser emitting modules, thereby forming a composite beam in which the second laser beam surrounds the first laser beam. Thus, during electrode cutting, the second laser beam located on the outer side of the composite beam can preheat the electrode, reducing the temperature rise required for the first laser beam located on the inner side of the composite beam to cut the electrode, thereby shortening the time required for electrode vaporization. This reduces the cutting time and number of cuts, improving electrode cutting efficiency. More importantly, it increases the vaporization rate of the aluminum foil layer, reducing the chance of aluminum foil layer liquefaction sputtering, effectively suppressing the formation of molten beads, and improving electrode quality.

[0103] This disclosure also provides a laser cutting system, including: a conveying mechanism (not shown), an air knife device 15, and a laser cutting device according to any of the above embodiments; the conveying mechanism is used to convey the item to be cut; the laser cutting device is disposed above the conveying mechanism, and the laser cutting device is used to emit and control a composite beam to scan the item to be cut back and forth along a preset trajectory so that the item to be cut forms a cutting surface; the air knife device 15 is disposed above the conveying mechanism, and the air knife device 15 is used to blow and clean the cutting surface.

[0104] In this embodiment, taking electrode 16 as an example, a laser cutting device is provided. By emitting and controlling a composite beam to scan back and forth along a preset trajectory, the electrode 16 can be cut to form a cut surface. The second laser beam 12, located on the outer side of the composite beam emitted by the laser cutting device, can preheat the electrode 16, reducing the temperature rise required for cutting by the first laser beam 11, thus improving cutting efficiency. The air knife device 15 is also provided, which cleans the cut surface, improving the quality of the electrode 16. It should be noted that in this embodiment, the structure of the laser cutting device is the same as that of any of the above embodiments, and its beneficial effects are similar; therefore, further details are omitted here.

[0105] In practical applications, when molten beads 1603 are inevitably generated during the cutting process of the electrode 16, since the upper surface of the electrode 16 containing molten beads 1603 and the upper side of the cut surface are within the irradiation range of the second laser beam 12, the adhesive in the dressing layer 1602 is heated and carbonized and decomposed under the high-frequency, low-energy bombardment of the second laser beam 12, losing its adhesiveness. This causes the local dressing layer 1602 to loosen and become loose lithium iron phosphate particles. Based on this, when the composite beam scans back and forth along a preset trajectory, a slit is formed on the electrode 16. The air knife device 15 can be set on one or both sides of the slit, so that the local dressing layer 1602 can be detached, thereby causing the molten beads 1603 on the surface of the dressing layer 1602 to fall off. After cleaning the electrode 16 after cutting, it is beneficial to improve the quality of the electrode 16.

[0106] It should be noted that after cleaning by the air knife device 15, the electrode 16 will have a notch on its upper surface, as shown in Figure 6. To avoid affecting the quality of the electrode 16, the width of the notch area is generally 1-2 mm, and the depth is less than 10 micrometers, with an impact on the capacity of the electrode 16 of less than 0.02%. Furthermore, since the adhesive melting point of the dressing layer 1602 is 180-200℃, and the wavelength of the second laser beam 12 is 1024 nm, it has strong penetrating power and can more easily project into the interior of the dressing layer 1602, causing the adhesive to carbonize and decompose upon heating. The air knife device 15 of this embodiment can be an existing product.

[0107] In some optional embodiments of this disclosure, the conveying mechanism includes a conveying plane for placing the item to be cut; the air outlet direction of the air knife device 15 is a first direction X, which is set at an angle to the conveying plane; the optical axis direction of the composite beam is a second direction Y, which is perpendicular to the conveying plane. Thus, taking the electrode 16 as an example, on the one hand, by controlling the angle between the first direction X and the conveying plane, the external dimensions of the notched area on the electrode 16 can be effectively controlled, which is beneficial to improving the quality of the electrode 16. On the other hand, when the electrode 16 is placed on the conveying plane, since the second direction Y is perpendicular to the conveying plane, that is, the optical axis direction of the composite beam is perpendicular to the electrode 16, a kerf of suitable width can be formed on the electrode 16.

[0108] In practical applications, the angle between the air outlet direction of the air knife device 15, i.e., the first direction X, and the conveying plane can be 0°-25°. Generally, when the angle between the air outlet direction of the air knife device 15 and the conveying plane is 0°, that is, the air outlet direction of the air knife device 15 is parallel to the conveying plane and the surface of the electrode 16, the molten beads 1603 splashed during the cutting process can be blown away in time, preventing the molten beads 1603 from falling back onto the upper surface of the electrode 16 and the cut surface due to gravity. When the angle between the air outlet direction of the air knife device 15 and the conveying plane is greater than 0°, as the angle increases, the volume of the notch formed on the electrode 16 increases, that is, more coating layer 1602 is blown away. While blowing away the splashed molten beads 1603, the molten beads 1603 on the upper surface of the electrode 16 and the cut surface can also be removed, thereby improving the cleaning effect of the electrode 16. However, this will also significantly affect the capacity of the electrode 16. Tests have shown that when the angle between the first direction X and the conveying plane is between 0° and 25°, the cleaning effect and capacity of the electrode 16 can be balanced.

[0109] It should be noted that the present invention does not limit the specific value of the angle between the air outlet direction of the air knife device 15, i.e., the first direction X, and the conveying plane. Those skilled in the art can adjust it according to actual needs. For example, the angle between the air outlet direction of the air knife device 15, i.e., the first direction X, and the conveying plane can be 0°, 5°, 13°, 20°, 25°, or other values.

[0110] In practical applications, the outlet air pressure of the air knife device 15 can be 0.1 kPa-0.3 kPa. Generally, the higher the outlet air pressure of the air knife device 15, the better the purging effect. However, when the outlet air pressure is too high, it can easily damage the electrode 16 or cause the electrode 16 to shift, affecting the cutting operation of the electrode 16. Testing has shown that when the outlet air pressure is 0.1 kPa-0.3 kPa, the purging effect of the air knife device 15 can be improved without affecting the electrode 16, which is beneficial to improving the quality of the electrode 16.

[0111] It should be noted that the specific value of the outlet air pressure of the air knife device 15 is not limited in this embodiment, and those skilled in the art can adjust it according to actual needs. For example, the outlet air pressure of the air knife device 15 can be 0.1kPa, 0.12kPa, 0.2kPa, 0.25kPa, 0.3kPa or other values.

[0112] This disclosure also provides a laser cutting method using the laser cutting system of any of the above embodiments. The laser cutting method includes: controlling a conveying mechanism to transport the item to be cut to the area below the laser cutting device; controlling the laser cutting device to emit a composite beam and scan the item to be cut back and forth along a preset trajectory to form a cutting surface on the item to be cut; and controlling an air knife device 15 to blow and sweep the cutting surface.

[0113] In this embodiment, taking electrode 16 cutting as an example, the laser cutting device can scan the electrode 16 to cut it and form a cut surface. The second laser beam 12, located on the outer side of the composite beam emitted by the laser cutting device, can preheat the electrode 16, reducing the temperature rise required for cutting by the first laser beam 11, thus improving cutting efficiency. The air knife device 15 can blow away molten beads 1603 splashed during cutting or existing on the upper surface and cut surface of the electrode 16, thereby cleaning the electrode 16 and improving its quality. It should be noted that in this embodiment, the structure of the laser cutting system is the same as that of any of the above embodiments, and its beneficial effects are similar, so further details are omitted here.

[0114] In some optional embodiments of this disclosure, the scanning speed of the galvanometer 13 in the scanning focusing module of the laser cutting apparatus is specifically 17000 mm / s-19000 mm / s. Generally, a higher scanning speed means that more cutting work can be completed per unit time, thereby improving the cutting efficiency of the laser cutting apparatus. However, a large scanning speed may cause the laser beam energy to disperse, affecting the cutting accuracy of the laser cutting apparatus and the quality of the cut item. Therefore, tests have shown that when the scanning speed of the galvanometer 13 is 17000 mm / s-19000 mm / s, the laser cutting apparatus can achieve both high cutting efficiency and cutting accuracy, improving the quality of the cut item.

[0115] It should be noted that the specific value of the scanning speed is not limited in the embodiments disclosed herein, and those skilled in the art can adjust it according to actual needs. For example, the scanning speed can be 17000mm / s, 18000mm / s, 18500mm / s, 19000mm / s or other values.

[0116] In practical applications, the pulse width of a laser beam refers to the duration of a laser pulse, reflecting the width or length of the laser pulse over time. A narrower pulse width results in higher peak energy, which in turn creates a stronger instantaneous bombardment of the workpiece, reducing heat accumulation time, increasing material vaporization rate, and decreasing the chance of material liquefaction and sputtering. This effectively suppresses the formation of molten beads 1603, thus improving the quality of the electrode 16. Based on this, in some optional embodiments of this disclosure, the pulse width of the first laser beam 11 is 1ns-50ns, and the pulse width of the second laser beam 12 is 1ns-300ns, meaning the pulse width of the first laser beam 11 is narrower, and the pulse width of the second laser beam 12 is wider. This allows the first laser beam 11 to have a larger peak energy, effectively suppressing the formation of molten beads 1603 during cutting. Conversely, it allows the second laser beam 12 to have a smaller peak energy, which can effectively preheat the workpiece and provide secondary bombardment heating to the generated molten beads 1603, preventing them from having sharp corners.

[0117] It should be noted that the specific values ​​of the pulse widths of the first laser beam 11 and the second laser beam 12 are not limited in this embodiment, and those skilled in the art can adjust them according to actual needs. For example, the pulse width of the first laser beam 11 can be 1ns, 5ns, 10ns, 25ns, 40ns, 50ns, or other values. The pulse width of the second laser beam 12 can be 1ns, 20ns, 50ns, 85ns, 130ns, 250ns, 300ns, or other values. During the cutting process of the electrode 16, the main function of the second laser beam 12, located on the outer side, is to preheat the electrode 16 and to bombard the molten bead 1603 a second time, while the main function of the first laser beam 11, located on the inner side, is to cut. Therefore, in this embodiment, the pulse width of the first laser beam 11 should be smaller than the pulse width of the second laser beam 12.

[0118] Generally, the higher the energy of the laser beam, the faster it can heat the material to its vaporization temperature, thus reducing the number of cuts and improving the processing efficiency of the laser cutting device. However, for the second laser beam 12 located on the outer side, excessive energy can lead to an excessively large heat-affected zone, resulting in material waste. For the first laser beam 11 located on the inner side, excessive energy can increase the divergence angle of the first laser beam 11, deteriorate the laser beam quality, and affect the cutting accuracy. Testing showed that when the energy of the first laser beam 11 is between 100W and 500W, the quality of the first laser beam 11 is good, reducing the number of cuts while improving cutting accuracy. When the energy of the second laser beam 12 is between 300W and 1000W, it can better preheat the electrode 16, reducing the temperature rise required when the first laser beam 11 cuts the electrode 16, shortening the time required for the electrode 16 to vaporize, thus improving the cutting efficiency of the electrode 16 and suppressing the formation of molten beads 1603.

[0119] It should be noted that the energy here refers to the laser energy output by the laser beam per unit time, that is, the rated energy of the laser beam. This embodiment does not limit the specific values ​​of the energy of the first laser beam 11 and the second laser beam 12, and those skilled in the art can adjust them according to actual needs. For example, the energy of the first laser beam 11 can be 100W, 150W, 300W, 400W, 500W, or other values. The energy of the second laser beam 12 can be 300W, 500W, 600W, 750W, 900W, 1000W, or other values.

[0120] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0121] Although embodiments of this disclosure have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this disclosure, the scope of which is defined by the claims and their equivalents.

Claims

1. A laser cutting device, applied to an item to be cut, characterized in that, The laser cutting device includes: a first laser emitting module, a second laser emitting module, and a beam combining module; The first laser emitting module is used to emit a first laser beam (11); The second laser emitting module is used to emit a second laser beam (12); The beam combining module is disposed on the light-emitting side of the first laser emitting module and the second laser emitting module. The beam combining module is used to receive and combine the first laser beam (11) and the second laser beam (12) to form a composite beam in which the second laser beam (12) is distributed around the first laser beam (11).

2. The laser cutting apparatus according to claim 1, characterized in that, The first laser beam (11) has a different wavelength than the second laser beam (12).

3. The laser cutting apparatus according to claim 2, characterized in that, The wavelength of the first laser beam (11) is shorter than the wavelength of the second laser beam (12).

4. The laser cutting apparatus according to claim 1, characterized in that, The first laser beam (11) irradiates the surface of the item to be cut to form a first light spot (1101), and the second laser beam (12) irradiates the surface of the item to be cut to form a second light spot (1201); The first light spot (1101) is circular, and the second light spot (1201) is annular.

5. The laser cutting apparatus according to any one of claims 1 to 4, characterized in that, The first laser emitting module includes: a first laser generator (1) and a first beam expander (3); The first laser generator (1) is used to generate the first laser beam (11); The first beam expander (3) is disposed on the light-emitting side of the first laser generator (1), and the first beam expander (3) is used to expand the diameter of the first laser beam (11).

6. The laser cutting apparatus according to claim 5, characterized in that, The first laser emitting module further includes a first reflector (2) and a second reflector (4). The first reflector (2) and the second reflector (4) are respectively disposed on the light-incident side and the light-outcident side of the first beam expander (3). The first reflector (2) and the second reflector (4) are used to change the optical axis direction of the first laser beam (11).

7. The laser cutting apparatus according to any one of claims 1 to 4, characterized in that, The second laser emitting module includes: a second laser generator (5), a second beam expander (7), an axonocone prism assembly (8), and a collimating lens (9); The second laser generator (5) is used to generate the second laser beam (12); The second beam expander (7) is disposed on the light-emitting side of the second laser generator (5), and the second beam expander (7) is used to expand the diameter of the second laser beam (12); The axial cone prism assembly (8) is disposed on the light-emitting side of the second beam expander (7), and the axial cone prism assembly (8) is used to change the shape of the second laser beam (12); The collimating lens (9) is disposed on the light-emitting side of the axial cone prism assembly (8), and the collimating lens (9) is used to change the divergence angle of the second laser beam (12).

8. The laser cutting apparatus according to claim 7, characterized in that, The axial cone prism assembly (8) includes: a first axial cone prism (81) and a second axial cone prism (82); The first axial cone prism (81) and the second axial cone prism (82) are symmetrically arranged along the optical axis of the second laser beam (12), with the first axial cone prism (81) close to the second beam expander (7); The first axial cone prism (81) has a first focal point located on the light-emitting side of the first axial cone prism (81), and the second axial cone prism (82) has a second focal point located on the light-incident side of the second axial cone prism (82), and the second focal point coincides with the first focal point.

9. The laser cutting apparatus according to claim 8, characterized in that, The base angles of the first axial cone prism (81) and the second axial cone prism (82) both satisfy: 1.5°-3°.

10. The laser cutting apparatus according to claim 7, characterized in that, The first laser emitting module further includes a third reflector (6), which is disposed between the second laser generator (5) and the second beam expander (7). The third reflector (6) is used to change the optical axis direction of the second laser beam (12).

11. The laser cutting apparatus according to any one of claims 1 to 4, characterized in that, The beam combining module includes a beam combining mirror (10); From the center of the beam combiner (10) to the edge of the beam combiner (10), the beam combiner (10) includes a transmission area and a reflection area distributed in sequence. The transmission area is used to transmit the first laser beam (11), and the reflection area is used to reflect the second laser beam (12) so that the optical axes of the first laser beam (11) and the second laser beam (12) coincide.

12. The laser cutting apparatus according to any one of claims 1 to 4, characterized in that, The laser cutting device also includes a scanning and focusing module; The scanning and focusing module is located on the light-emitting side of the beam combining module and above the item to be cut. The scanning and focusing module is used to apply the composite beam to the surface of the item to be cut in order to achieve cutting.

13. The laser cutting apparatus according to claim 12, characterized in that, The scanning focusing module includes a galvanometer (13) and a field lens (14) connected to each other, with the galvanometer (13) positioned close to the beam combining module; The galvanometer (13) is used to receive and control the composite beam to scan along a preset trajectory; The field lens (14) is used to focus the composite beam onto the surface of the object to be cut.

14. A laser cutting system, characterized in that, The laser cutting system includes: a conveying mechanism, an air knife device (15), and a laser cutting apparatus according to any one of claims 1-13; The conveying mechanism is used to convey items to be cut; The laser cutting device is positioned above the conveying mechanism. The laser cutting device is used to emit and control a composite beam to scan the item to be cut back and forth along a preset trajectory, so that the item to be cut forms a cut surface. The air knife device (15) is disposed above the conveying mechanism, and the air knife device (15) is used to blow the cutting surface.

15. The laser cutting system according to claim 14, characterized in that, The conveying mechanism includes a conveying plane for placing the item to be cut. The air outlet direction of the air knife device (15) is the first direction (X), and the first direction (X) is set at an angle to the conveying plane.

16. The laser cutting system according to claim 15, characterized in that, The angle between the first direction (X) and the conveying plane is 0°-25°.

17. The laser cutting system according to claim 14, characterized in that, The conveying mechanism includes a conveying plane for placing the item to be cut. The optical axis of the composite beam is the second direction (Y), which is perpendicular to the delivery plane.

18. A laser cutting method, characterized in that, The laser cutting system according to any one of claims 14-17, wherein the laser cutting method comprises: The control conveyor mechanism transports the items to be cut to the bottom of the laser cutting device; The laser cutting device is controlled to emit a composite beam and scan the object to be cut back and forth along a preset trajectory, so that the object to be cut forms a cutting surface; Control the air knife device (15) to blow the cut surface.

19. The laser cutting method according to claim 18, characterized in that, The scanning speed of the laser cutting device is 17000mm / s-19000mm / s.

20. The laser cutting method according to claim 18, characterized in that, The wavelength of the first laser beam (11) is 280nm-600nm; And / or, the pulse width of the first laser beam (11) is 1ns-50ns; And / or, the energy of the first laser beam (11) is 100W-500W.

21. The laser cutting method according to claim 18, characterized in that, The wavelength of the second laser beam (12) is 900nm-10600nm; And / or, the pulse width of the second laser beam (12) is 1ns-300ns; And / or, the energy of the second laser beam (12) is 300W-1000W.

22. The laser cutting method according to claim 18, characterized in that, The laser cutting device performs 5-12 scans.

23. The laser cutting method according to claim 18, characterized in that, The outlet air pressure of the air knife device (15) is 0.1kPa-0.3kPa.

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