阅读说明：本技术 分段激光切割方法 (Segmented laser cutting method ) 是由 张格� 吴丹 王涛 郑付成 黄东海 高云峰 于 2021-09-29 设计创作，主要内容包括：本发明公开了一种分段激光切割方法,可根据极耳规格参数确定极耳切割路径以及直线切割路径,由第一振镜系统沿极耳切割路径对金属箔材进行切割,由第二振镜系统沿直线切割路径对涂层进行切割,并通过第一振镜系统和第二振镜系统交替对物料进行激光切割,最后形成所需的极耳。本发明可以避免振镜系统因激光切割路径过长而出现激光能量衰减的情况,同时可以根据对应切割轨迹的特点,分别选择合适参数的第一振镜系统和第二振镜系统,提高其适应性,从而对设备高速运行时物料的抖动具有一定的容错率,可有效地切断废料并避免废料带来的抖动问题。(The invention discloses a segmented laser cutting method, which can determine a tab cutting path and a linear cutting path according to tab specification parameters, wherein a first galvanometer system cuts a metal foil along the tab cutting path, a second galvanometer system cuts a coating along the linear cutting path, and the first galvanometer system and the second galvanometer system alternately cut the material by laser to finally form a required tab. The invention can avoid the situation that the laser energy of the galvanometer system is attenuated due to the overlong laser cutting path, and simultaneously can respectively select the first galvanometer system and the second galvanometer system with proper parameters according to the characteristics of the corresponding cutting track, thereby improving the adaptability of the galvanometer system, having certain fault-tolerant rate on the jitter of materials when equipment runs at high speed, effectively cutting off waste materials and avoiding the jitter problem caused by the waste materials.)

1. A method of segmented laser cutting, comprising the steps of:

conveying a material to cutting positions of a first galvanometer system and a second galvanometer system, wherein the material comprises a metal foil and a coating, and the coating is attached to the metal foil;

determining a tab cutting path and a linear cutting path according to the tab specification parameters;

the first galvanometer system cuts the metal foil along the tab cutting path;

the second galvanometer system cuts the coating along a linear cutting path, and the linear cutting path is intersected with the tab cutting path;

the first galvanometer scanning system and the second galvanometer scanning system alternately cut the material, so that the cut material forms a tab.

2. The segmented laser cutting method according to claim 1, wherein the ends of the tab cutting paths form first radiused corners and extend through the first radiused corners to the coating layer, and the ends of the straight cutting paths form second radiused corners and extend through the second radiused corners to the metal foil.

3. The segmented laser cutting method according to claim 2, wherein the intersection of the tab cutting path and the straight cutting path is located at the boundary of the coating and the metal foil.

4. The segmented laser cutting method according to claim 2, wherein the arc diameter of the first arc corner is larger than the arc diameter of the second arc corner.

5. The segmented laser cutting method of claim 1, wherein the metal foil is cut along the tab cutting path by the first galvanometer system and the coating is cut along the linear cutting path by the second galvanometer system.

6. The segmented laser cutting method according to claim 1, wherein a focal depth of the first galvanometer system is larger than a focal depth of the second galvanometer system.

7. The segmented laser cutting method according to claim 1, wherein the tab specification parameters include tab size and tab spacing, the tab size includes tab arc angle, tab length and tab width, and the tab spacing includes adjacent tab centerline distance.

8. The segmented laser cutting method according to claim 1, wherein the material is in a conveying state when the material is subjected to laser cutting by the first galvanometer system or the second galvanometer system.

9. The segmented laser cutting method according to claim 8, wherein when the material is cut by the first galvanometer system or the second galvanometer system, the relation between the conveying speed of the material and the laser energy is as follows:

P＝P₀+K₁*v₁

in the formula, v₁Is the material conveying speed, P is the real-time energy of the laser in the first galvanometer system or the second galvanometer system, P₀When the material conveying speed is 0, the laser energy of the laser in the first galvanometer system or the second galvanometer system is K₁Is an energy scaling factor.

10. The segmented laser cutting method according to claim 8, wherein when the material is cut by the first galvanometer system or the second galvanometer system, the relation between the conveying speed of the material and the laser frequency is as follows:

F＝F₀+K₂*ν₁

in the formula (I), the compound is shown in the specification,v₁is the material conveying speed, F is the real-time frequency of the laser in the first galvanometer system or the second galvanometer system, F₀When the material conveying speed is 0, the laser frequency K of the laser in the first galvanometer system or the second galvanometer system₂Is a frequency scaling factor.

Technical Field

The invention relates to the technical field of laser cutting, in particular to a segmented laser cutting method.

Background

With the continuous expansion of the market scale of new energy automobiles, the demand of power batteries is getting larger and larger, and the power lithium batteries are also receiving higher attention. The lug die cutting belongs to the front section process of a power lithium battery cell manufacturing process, and at present, the lug die cutting has two modes of hardware die cutting and laser die cutting. The problem of cutter abrasion exists in hardware die cutting, the cutting process is easy to be unstable, the phenomenon of poor quality of pole piece die cutting occurs, and the performance of the battery is reduced. The laser die cutting has the characteristics of high production efficiency, good process stability and the like, and is widely used for the pole lug die cutting of the power lithium battery.

The principle of tab laser die cutting is that laser beams act on a battery pole piece according to a certain track under the action of a galvanometer system, so that tab die cutting is completed. However, in the process of die cutting of the tab by laser, when the material winding and unwinding speed is greater than 90m/min, the foil part of the material is easy to shake, so that the foil part of the material exceeds the depth range of laser cutting, the cut part cannot be cut off, the phenomenon of material carrying occurs, the shaking of the foil is further aggravated, and the cutting precision and the cutting efficiency of the tab die cutting are seriously affected.

Disclosure of Invention

In view of the defects of the prior art, the invention provides the segmented laser cutting method, which can effectively cut off materials in the laser cutting process, avoid the occurrence of the strip condition and improve the cutting precision and the cutting efficiency of laser cutting.

The embodiment adopts the following technical scheme:

a segmented laser cutting method comprising the steps of:

conveying a material to cutting positions of a first galvanometer system and a second galvanometer system, wherein the material comprises a metal foil and a coating, and the coating is attached to the metal foil;

determining a tab cutting path and a linear cutting path according to the tab specification parameters;

the first galvanometer system cuts the metal foil along the tab cutting path;

the second galvanometer system cuts the coating along a linear cutting path, and the linear cutting path is intersected with the tab cutting path;

the first galvanometer scanning system and the second galvanometer scanning system alternately cut the material, so that the cut material forms a tab.

Further, in the segmented laser cutting method, the end of the tab cutting path forms a first circular arc corner and extends to the coating layer through the first circular arc corner, and the end of the straight cutting path forms a second circular arc corner and extends to the metal foil through the second circular arc corner.

Further, in the segmented laser cutting method, the intersection point of the tab cutting path and the straight cutting path is located at the boundary of the coating layer and the metal foil.

Further, in the segmented laser cutting method, the arc diameter of the first arc corner is larger than the arc diameter of the second arc corner.

Further, in the segmented laser cutting method, the metal foil is cut by the first galvanometer system along the tab cutting path, and then the coating is cut by the second galvanometer system along the linear cutting path.

Further, in the segmented laser cutting method, the focal depth of the first galvanometer system is larger than the focal depth of the second galvanometer system.

Further, in the segmented laser cutting method, the tab specification parameters include tab size and tab spacing, the tab size includes a tab arc angle, tab length and tab width, and the tab spacing includes an adjacent tab centerline distance.

Further, in the segmented laser cutting method, when the material is subjected to laser cutting by the first galvanometer system or the second galvanometer system, the material is in a conveying state.

Further, in the segmented laser cutting method, when the material is subjected to laser cutting by the first galvanometer system or the second galvanometer system, the relationship between the conveying speed of the material and the energy of the laser is as follows:

P＝P₀+K₁*v₁

in the formula, v₁Is the material conveying speed, P is the real-time energy of the laser in the first galvanometer system or the second galvanometer system, P₀When the material conveying speed is 0, the laser energy of the laser in the first galvanometer system or the second galvanometer system is K₁Is an energy scaling factor.

Further, in the segmented laser cutting method, when the material is subjected to laser cutting by the first galvanometer system or the second galvanometer system, the relationship between the conveying speed of the material and the laser frequency is as follows:

F＝F₀+K₂*v₁

in the formula, v₁Is the material conveying speed, F is the real-time frequency of the laser in the first galvanometer system or the second galvanometer system, F₀When the material conveying speed is 0, the laser frequency K of the laser in the first galvanometer system or the second galvanometer system₂Is a frequency scaling factor.

Compared with the prior art, the segmented laser cutting method provided by the invention can be used for decomposing a laser cutting track into a polar lug cutting path and a linear cutting path, and alternately performing laser cutting through the first vibrating mirror system and the second vibrating mirror system, so that the situation of laser energy attenuation caused by overlong laser cutting path is avoided. Meanwhile, the first galvanometer system and the second galvanometer system with proper parameters can be respectively selected according to the characteristics of the corresponding cutting track, so that the adaptability of the laser scanning device is improved, a certain fault-tolerant rate is realized on the jitter of materials when the device runs at a high speed, the waste can be effectively cut off, and the problem of jitter caused by the waste can be avoided.

Drawings

Fig. 1 is a flowchart of a segmented laser cutting method provided by the present invention.

Fig. 2 is a schematic cut-away view of the first galvanometer system and the second galvanometer system of the embodiment of fig. 1.

Fig. 3 is a schematic diagram of a tab cutting track of the embodiment in fig. 1.

FIG. 4 is a schematic diagram of a linear cutting path of the embodiment of FIG. 1.

Fig. 5 is a schematic diagram of a combined cutting track of the tab cutting track and the straight cutting track of the embodiment in fig. 1.

110, a laser; 111. a laser fiber; 112. a laser head; 113. a galvanometer; 114. a field lens; 115. a laser beam; 116. a metal foil; 117. coating; 118. a guide roller; 119. driving the Z axis; 120. driving the XY axes; 121. a support platform; 200. a tab cutting path; 300. a linear cutting path; 400. the cutting paths are combined.

Detailed Description

In order to make the objects, technical solutions and effects of the present invention clearer and clearer, the present invention is further described in detail below with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention, which is not further described, and that elements, structures and features of one embodiment may be beneficially incorporated in other embodiments.

Referring to fig. 1, the segmented laser cutting method provided by the present invention includes the steps of:

s100, conveying materials to cutting positions of a first galvanometer system and a second galvanometer system, wherein the materials comprise a metal foil 116 and a coating 117, and the coating 117 is attached to the metal foil 116;

s200, determining a tab cutting path and a linear cutting path according to the tab specification parameters;

s300, cutting the metal foil 116 along a tab cutting path by the first galvanometer system;

s400, cutting the coating 117 by the second galvanometer system along a linear cutting path, wherein the linear cutting path is intersected with the tab cutting path;

s500, alternately cutting the material by the first vibrating mirror system and the second vibrating mirror system to enable the cut material to form a tab.

Referring to fig. 2, the material of the present invention is a power lithium battery material, i.e., a pole piece, the pole piece includes a metal foil 116 and a coating 117, and the specific material of the metal foil 116 and the specific material of the coating 117 can be selected according to the requirement. For example, when the electrode plate is a positive electrode plate, the metal foil 116 may be an aluminum foil, when the electrode plate is a negative electrode plate, the metal foil 116 may be a copper foil, and the coating 117 may be a ceramic, a graphite, or the like.

The first lens vibrating system and the second lens vibrating system can generate laser beams 115 to the laser head 112 through the laser 110, the deflection of the laser beams is controlled by the lens vibrating 113, the laser beams 115 are focused by the field lens 114 and then emitted to the surface of a material, the laser beams 115 are cut on the surface of the material along a specified scanning path, redundant waste materials are cut off, and therefore the required power lithium battery tab is formed.

Referring to fig. 3-5, the present invention decomposes the laser cutting path of the tab into a tab cutting path 200 and a linear cutting path 300 by using a step cutting method, and then combines the tab cutting path 200 and the linear cutting path 300 to form a combined cutting path 400, and finally replaces the original laser cutting path with a plurality of consecutive combined cutting tracks 400 to form the required tab. The invention can avoid the situation that the laser energy is attenuated due to the overlong cutting path of the galvanometer system in the continuous cutting process, and avoid the situation that the material cannot be cut off due to insufficient laser energy.

Meanwhile, according to the characteristics of a tab cutting path and a linear cutting path, the first galvanometer system and the second galvanometer system with appropriate parameters can be respectively selected. For example, because the change range of the tab cutting path is large, the first galvanometer system with a larger focal depth range can be selected, so that the tab cutting path can be cut more accurately, the change range of the linear cutting path is small, and the focal depth range of the second galvanometer system can be smaller than that of the first galvanometer system, so that the fault tolerance rate for the shaking of materials when the equipment runs at a high speed is certain, the waste can be effectively cut off, and the shaking problem caused by the waste can be avoided.

In addition, since the laser beam 115 generally generates a large amount of dust when cutting the coating 117, cutting accuracy is affected. By decomposing the laser cutting track of the tab into the tab cutting path 200 and the linear cutting path 300, the cutting parameters of the two sections of cutting paths can be adjusted, and staggered time exists during cutting, so that the influence of dust generated during cutting of the laser along the linear cutting path on the cutting of the laser along the tab cutting path can be reduced, and the cutting precision of the tab is improved.

Specifically, in step S100, the material may be conveyed to the cutting positions of the first galvanometer system and the second galvanometer system in an unwinding and winding manner, that is, the conveying front end and the conveying rear end of the material are provided with the corresponding unwinding mechanism and winding mechanism to provide power for conveying the material. Referring to fig. 2, the material may be transported on the guide rollers 118, and the guide rollers 118 support the material and determine the material transporting direction.

Taking the direction shown in fig. 2 as an example, the first galvanometer system and the second galvanometer system can be arranged on one side of the material, and an up-down superposition structural mode is adopted, and the galvanometers of the first galvanometer system and the second galvanometer system can be combined with corresponding driving platforms to move. In this embodiment, the first galvanometer system and the second galvanometer system are both arranged on the driving Z axis 119, so that the first galvanometer system or the second galvanometer system can move up and down, and the distance between the first galvanometer system and the second galvanometer system is adjustable; meanwhile, the first galvanometer system and the second galvanometer system are respectively arranged on the corresponding driving XY axes 120, so that the first galvanometer system and the second galvanometer system can move back and forth along the XY axes. The field lens 114 with larger focal depth is selected by the first galvanometer system, so that the cutting range is larger, and the characteristics of the tab cutting path 200 are adapted; the second galvanometer system can select the field lens 114 with smaller focal depth, thereby saving the equipment cost.

During the cutting process, the position of the laser focus needs to be determined, and the laser focus is ensured to be on the cutting track during the cutting process. The focal position of the first galvanometer system or the second galvanometer system is the distance from the field lens plane to the material cutting surface, and the size of the focal position can be determined according to the following formula:

wherein D1 is the first galvanometerDistance of the field lens plane of the system or of the second galvanometer system to the surface of the material cut, d_fThe diameter of the laser spot after laser focusing, M²For the quality factor of the laser beam, k is a correction coefficient, the size of k is between 0.1 and 0.9, and λ is the laser wavelength of the first galvanometer system or the second galvanometer system.

In the cutting process, a flight cutting technology can be adopted, so that the first vibrating mirror system and the second vibrating mirror system perform non-stop cutting on the material, namely, when the material is subjected to laser cutting by the first vibrating mirror system or the second vibrating mirror system, the material keeps a conveying state, and the cutting efficiency is improved.

When the material is subjected to laser cutting by the first galvanometer system or the second galvanometer system, a laser energy following mode is adopted, and the formula is as follows:

P＝P₀+K₁*v₁ (2)

in the formula, v₁Is the material conveying speed, P is the real-time energy of the laser in the first galvanometer system or the second galvanometer system, P₀When the material conveying speed is 0, the laser energy of the laser in the first galvanometer system or the second galvanometer system is K₁Is an energy scaling factor.

Meanwhile, when the material is subjected to laser cutting by the first galvanometer system or the second galvanometer system, a mode of laser frequency following is adopted, and the formula is as follows:

F＝F₀+K₂*v₁ (3)

in the formula, v₁Is the material conveying speed, F is the real-time frequency of the laser in the first galvanometer system or the second galvanometer system, F₀When the material conveying speed is 0, the laser frequency K of the laser in the first galvanometer system or the second galvanometer system₂Is a frequency scaling factor.

Specifically, in step S200, the tab specification parameters include a tab size and a tab spacing, the tab size includes a tab arc angle, a tab length and a tab width, and the tab spacing includes an adjacent tab centerline distance. The shape of the tab to be cut can be determined according to the tab specification parameters, and a corresponding tab cutting track 200 is formed; and determining the distance between the tabs to be cut to form a corresponding straight cutting track 300.

In step S300, the metal foil 116 is cut by the first galvanometer system along the tab cutting path 200, then the coating 117 is cut by the second galvanometer system along the linear cutting path 300 through step S400, and finally the steps S300 and S400, that is, step S500, are repeated to form a continuous combined cutting path 400 on the material, and to cut off the waste material on the material and form the required tab.

During cutting, the material is typically tensioned against the guide rollers 119 in order to improve the cutting accuracy. If cutting is performed along the linear cutting path 300, after the metal foil 116 is separated from the coating 117, the tension of the whole material is affected, so that the material cannot be tightened, and the cutting precision of the tab is affected. Therefore, the tab cutting path 200 precedes the straight cutting path 300 in cutting. The cutting of the tab part is started first, then the linear cutting is carried out, and finally the required tab is formed.

Specifically, with continued reference to fig. 3-5, the end of tab cutting path 200 forms a first radiused corner through which it extends to coating 117, and the end of straight cutting path 300 forms a second radiused corner through which it extends to foil 116.

At the bending part of the cutting track, the cutting is carried out through the first arc corner and the second arc corner, the laser beam 115 moves more uniformly and smoothly during the cutting, the cutting time is longer, compared with the straight line bending angle, the material is more easily cut off, and the material carrying is prevented. In addition, the joint of the formed tab and the coating is arc-shaped, so that the tab is not easy to deflect in subsequent processing. In addition, the arc diameter of the first arc corner is larger than that of the second arc corner, and the tab is further prevented from deflecting.

The intersection of tab cutting path 200 and linear cutting path 300 may be located at the boundary of coating 117 and foil 116, which may ensure that the tab shape is complete, while ensuring that excess scrap is accurately cut away.

For a better understanding of the present invention, referring to fig. 1-5, the segmented laser cutting method provided by the present invention will be described with reference to specific embodiments.

Step one, a first galvanometer system and a second galvanometer system are arranged, laser beams with proper parameters are selected, the wavelength range of the laser beams is 1020-1080 nm, the single pulse energy of the laser beams is 0.2-1.5 mJ, the spot size of the laser beams is 30-70 um, and the laser power is 200-300W.

And step two, conveying the material through a guide roller 119, adjusting the positions of the first galvanometer system and the second galvanometer system through a corresponding driving Z axis 119 and a corresponding driving XY axis 120 after determining a material cutting plane, determining the focal position of the laser beam through a formula (1), and setting process parameters through a formula (2) and a formula (3).

And step three, the first galvanometer system and the second galvanometer system alternately perform laser cutting on the material along the set tab cutting path 200 and the set linear cutting path 300, the material is kept in a conveying state in the cutting process, the distance between the first galvanometer system and the second galvanometer system is adjusted in real time, the tab cutting path 200 is ensured to be connected with the linear cutting path 300, and the waste material is accurately cut off to form the required tab.

The segmented laser cutting method provided by the invention can bring the following effects:

1. the pole lug yields after the cutting are good, reduces and produces the risk that the utmost point ear does not cut off and appear the belting because of the shake in the cutting process.

2. Can meet the requirements of laser cutting of the lug with high efficiency and high quality at present.

3. The laser cutting of the lugs with different lug specification parameters and different material winding and unwinding speeds can be realized.

4. The control of tab mass production and yields of being convenient for entrepreneurization.

It should be understood that equivalents and modifications of the technical solution and inventive concept thereof may occur to those skilled in the art, and all such modifications and alterations should fall within the scope of the appended claims.