Laser cutting method and laser device

Abstract

The invention provides a laser cutting method and a laser device. The laser cutting method comprises the following steps that a battery pack is placed in a cutting area; a laser head is used for emitting a laser beam to cut the connecting piece of the battery pack, the ratio of the focal length of a focus lens set in the laser head to the focal length of a collimating lens set in the laser head is 0-1, the cutting defocusing amount during laser beam cutting is-2mm-3mm, and the cutting defocusing amount is the distance between the focal point of the laser beam and the upper surface of the connecting piece. When the laser cutting method is used for cutting the connecting piece of the battery pack, the battery surface below the connecting piece of the battery pack can be prevented from being damaged by laser, and it is guaranteed that the cutting process is safe and reliable.

Description

Technical Field

[0001] The present application belongs to the field of laser cutting technology, and more specifically, relates to a laser cutting method and a laser device. Background Art

[0002] Laser cutting technology is widely used in many industries and fields, such as metal processing industry, automobile manufacturing industry, electronic and electrical industry, etc. With the continuous development and innovation of laser technology, its application in various industries is becoming more and more diversified.

[0003] In recent years, the new energy vehicle industry has developed rapidly. However, with the rapid popularization of electric vehicles, power batteries, as core components of new energy vehicles, are about to face a wave of retirement. The treatment of waste power batteries is a huge challenge. Improper treatment will cause great harm to the environment and human health. The recycling of power batteries is of great significance. The cutting and disassembly of battery pack connectors is an important part of power battery recycling. Laser cutting has the characteristics of high precision, high efficiency and high quality, and has great potential for cutting battery pack connectors. However, laser beams usually have high penetration. If they are not handled properly, the laser may penetrate the battery shell and cause safety accidents such as combustion or explosion. Summary of the invention

[0004] The present application provides a laser cutting method, which can ensure battery safety when cutting the battery casing.

[0005] The technical solution adopted in this application is a laser cutting method, comprising the following steps:

[0006] Place the battery pack in the cutting area;

[0007] A laser head is used to emit a laser beam to cut the connecting piece of the battery pack, wherein the ratio between the focal length of the focusing lens group and the focal length of the collimating lens group in the laser head is 0 to 1, and the cutting defocus amount of the laser beam during cutting is -2 mm to 3 mm, and the cutting defocus amount is the distance between the focus of the laser beam and the upper surface of the connecting piece.

[0008] In the laser cutting method of the present application, the ratio between the focal length of the focusing lens group and the focal length of the collimating lens group in the laser head is set to 0-1. The laser beam has good convergence after passing through the laser head, and a larger beam divergence angle A can be obtained. In addition, the cutting defocus amount Fc of the laser beam combined with the present application is -2mm-3mm. When cutting the connecting piece of the battery pack, this cutting method can avoid laser damage to the battery surface under the connecting piece of the battery pack, thereby ensuring a safe and reliable cutting process.

[0009] Optionally, the ratio between the focal length of the focusing lens group and the focal length of the collimating lens group of the laser head is 0.3-1.

[0010] Optionally, the ratio between the focal length of the focusing lens group and the focal length of the collimating lens group is 0.5.

[0011] Optionally, the cutting defocus amount during laser beam cutting is 0 mm to 1 mm.

[0012] Optionally, the cutting defocus amount during the laser beam cutting is 0.

[0013] Optionally, the method further comprises:

[0014] A laser is used to transmit a laser beam to a laser head through a transmission optical fiber, wherein the core diameter of the transmission optical fiber is 50 μm to 300 μm.

[0015] Optionally, the spot diameter of the laser beam is 25 μm to 300 μm.

[0016] Optionally, the beam divergence angle of the laser beam is 100 mrad to 550 mrad.

[0017] A laser cutting method comprises the following steps:

[0018] Placing a battery pack in a cutting area, wherein the battery pack includes a plurality of batteries and a connecting piece for connecting the plurality of batteries;

[0019] A laser head is used to emit a laser beam to cut the connecting piece corresponding to the gap between the batteries, wherein the ratio between the focal length of the focusing lens group and the focal length of the collimating lens group in the laser head is 0 to 1, and the cutting defocus amount of the laser beam during cutting is -2 mm to 3 mm, and the cutting defocus amount is the distance between the focus of the laser beam and the upper surface of the connecting piece.

[0020] A laser device for cutting a connecting piece of a battery pack comprises a laser, a transmission optical fiber and a laser head, wherein the laser is connected to the laser head via the transmission optical fiber; wherein:

[0021] The ratio between the focal length of the focusing lens group and the focal length of the collimating lens group in the laser head is 0 to 1;

[0022] The cutting defocus amount when the laser head emits a laser beam for cutting is -2mm to 3mm, and the cutting defocus amount is the distance between the focus of the laser beam and the upper surface of the connecting piece. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0024] Figure 1 This is a schematic diagram of the process of the laser cutting method in the embodiment of the present application;

[0025] Figure 2 This is a schematic diagram of the structure of the laser device in the embodiment of the present application;

[0026] Figure 3 This is a schematic diagram of cutting a connecting piece using a laser cutting method in an embodiment of the present application;

[0027] Figure 4 This is a schematic diagram of the internal structure of a laser head in a laser device in an embodiment of the present application;

[0028] Figure 5 Schematic diagram of the effect of the laser beam in the laser cutting method in the embodiment of the present application;

[0029] Figure 6 This is an example schematic diagram of the cutting defocus amount in the laser cutting method in an embodiment of the present application.

[0030] Reference numerals

[0031] 100, laser head; 110, collimating lens group; 120, focusing lens group; 200, laser; 300, transmission optical fiber; 400, laser beam; 500, battery pack; 510, battery; 520, connecting piece. Specific embodiments

[0032] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0033] It should be noted that when a metastructure is referred to as being "fixed to" or "set on" another metastructure, it can be directly on the other metastructure or indirectly on the other metastructure. When a metastructure is referred to as being "connected to" another metastructure, it can be directly connected to the other metastructure or indirectly connected to the other metastructure.

[0034] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element structure referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0035] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of some applications, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0036] The present application provides a laser cutting method, which can connect connecting pieces on a battery pack and prevent the laser from penetrating the battery casing.

[0037] like Figure 2 and Figure 3 As shown, in some embodiments, the battery pack 500 may include a plurality of batteries 510 and a connecting piece 520 for connecting the plurality of batteries 510. The cutting method of the present application can cut the connecting piece 520 for connecting the batteries 510 and can prevent the laser from penetrating the outer shell of the battery 510.

[0038] See also Figure 1 , a laser cutting method, comprising the following steps:

[0039] Step S100: placing the battery pack in the cutting area.

[0040] Step S300, using a laser head to emit a laser beam to cut the connecting piece of the battery pack, wherein the ratio between the focal length of the focusing lens group and the focal length of the collimating lens group in the laser head is 0 to 1, and the cutting defocus amount during laser beam cutting is -2 mm to 3 mm, and the cutting defocus amount is the distance between the focus of the laser beam and the upper surface of the connecting piece.

[0041] For details, see Figure 2 and Figure 3 , the laser head 100 can be located above the battery pack 500, and the laser beam 400 emitted by the laser head 100 can act on the connecting piece 520 of the battery pack 500 for cutting. After the connecting piece 520 is cut off, the battery 510 on the battery pack 500 is separated.

[0042] See also Figure 4The laser head 100 may include a collimating lens group 110 and a focusing lens group 120. Specifically, the laser beam 400 may pass through the collimating lens group 110 and the focusing lens group 120 in the laser head 100 and then irradiate the connecting piece 520 of the battery pack 500.

[0043] The collimating lens assembly 110 has a collimating focal length F1, the focusing lens assembly 120 has a focusing focal length F2, and the ratio of F2 to F1 is 0-1.

[0044] Furthermore, the cutting defocus amount Fc of the laser beam 400 during cutting is -2mm to 3mm. The cutting defocus amount specifically refers to the distance between the focus of the laser beam 400 and the upper surface of the connecting piece 520. Therefore, the cutting defocus amount Fc of the laser beam 400 during cutting is -2mm to 3mm, which means that the focus of the laser beam 400 is located in the range of 2mm below the upper surface of the connecting piece 520 of the battery pack 500 to 3mm above the upper surface.

[0045] Understandable, see Figure 6 The cutting defocus amount Fc can be divided into negative defocus (-), zero defocus (0), and positive defocus (+) according to the positional relationship between the focus of the laser beam 400 and the upper surface of the connecting piece 520 of the battery pack 500. Negative defocus means that the focus of the laser beam 400 is below the upper surface of the connecting piece 520 of the battery pack 500, positive defocus means that the focus of the laser beam 400 is above the upper surface of the connecting piece 520 of the battery pack 500, and zero defocus means that the focus of the laser beam 400 coincides with the upper surface of the connecting piece 520 of the battery pack 500.

[0046] In addition, along the propagation direction of the laser beam 400, after the laser beam 400 passes the focus, the beam divergence angle A plays an important role in the attenuation of the energy density of the laser beam 400. When the beam divergence angle A is small, the spot diameter of the laser beam 400 changes less as the propagation distance increases, and the energy density decays more slowly. When cutting, the laser beam 400 may still maintain a high energy density after penetrating the connecting piece 520 of the battery pack 500 to propagate to the upper surface of the battery 510 closer below, thereby damaging the upper surface of the battery 510, or even penetrating the outer shell of the battery 510, which may cause safety accidents such as combustion or explosion. When the beam divergence angle A is large, the spot diameter of the laser beam 400 changes more as the propagation distance increases, and the energy density decays more quickly. When cutting, the laser beam 400 penetrates the connecting piece 520 of the battery pack 500 and propagates downward, and the energy density can decay rapidly as the distance increases. When reaching the upper surface of the battery 510 closer below, the energy density of the laser beam 400 is already low, which is not enough to damage the upper surface of the battery 510, thereby ensuring the safety and reliability of the cutting process.

[0047] In the laser cutting method of the present application, the ratio between the focal length of the focusing lens group 120 and the focal length of the collimating lens group 110 in the laser head 100 is set to 0-1. The laser beam 400 has good convergence after passing through the laser head 100, and a larger beam divergence angle A can be obtained. In addition, in the present application, the cutting defocus amount Fc of the laser beam 400 is -2mm-3mm. When the cutting method is used to cut the connecting piece 520 of the battery pack 500, it can avoid laser damage to the surface of the battery 510 under the connecting piece 520 of the battery pack 500, thereby ensuring a safe and reliable cutting process.

[0048] Specifically, in some embodiments, the battery pack 500 may include a plurality of batteries 510 and a connecting piece 520 for connecting the plurality of batteries 510 . The laser beam 400 emitted by the laser head 100 cuts the connecting piece 520 corresponding to the gap between the batteries 510 . This method can further avoid laser damage to the outer surface of the battery 510 .

[0049] In some embodiments, the collimation focal length F1 of the collimating lens assembly 110 may include 75 mm, 100 mm, 125 mm, 150 mm, 200 mm, 250 mm, 300 mm, 400 mm, 500 mm, and 600 mm. Correspondingly, the focus focal length F2 of the focusing lens assembly 120 may include 75 mm, 100 mm, 125 mm, 150 mm, 200 mm, 250 mm, 300 mm, 400 mm, 500 mm, and 600 mm.

[0050] Preferably, while ensuring that the laser beam 400 has a large divergence angle, taking into account the sizes of the focusing lens group 120 and the collimating lens group 110, and taking into account the cutting distance between the laser head 100 and the battery pack 500, the ratio between the focal length of the focusing lens group 120 of the laser head 100 and the focal length of the collimating lens group 110 can be 0.3 to 1. That is, the ratio of the focal length F2 of the focusing lens group 120 to the focal length F1 of the collimating lens group 110 is 0.3 to 1.

[0051] For example, the combination of the focusing lens group 120 and the collimating lens group 110 may include any one of the following groups:

[0052] The focal length of the focusing lens group 120 is 75, and the focal length of the collimating lens group 110 is 75; the focal length of the focusing lens group 120 is 75, and the focal length of the collimating lens group 110 is 100; the focal length of the focusing lens group 120 is 75, and the focal length of the collimating lens group 110 is 125; the focal length of the focusing lens group 120 is 75, and the focal length of the collimating lens group 110 is 150; the focal length of the focusing lens group 120 is 75, and the focal length of the collimating lens group 110 is 200; the focal length of the focusing lens group 120 is 75, the focal length of the collimator lens group 110 is 250; the focal length of the focusing lens group 120 is 100, and the focal length of the collimator lens group 110 is 100; the focal length of the focusing lens group 120 is 100, and the focal length of the collimator lens group 110 is 125; the focal length of the focusing lens group 120 is 100, and the focal length of the collimator lens group 110 is 150; the focal length of the focusing lens group 120 is 100, and the focal length of the collimator lens group 110 is 200; the focal length of the focusing lens group 120 is 100, and the collimator lens group 110 is The focal length of the focusing lens group 120 is 125, and the focal length of the collimating lens group 110 is 125; the focal length of the focusing lens group 120 is 125, and the focal length of the collimating lens group 110 is 150; the focal length of the focusing lens group 120 is 125, and the focal length of the collimating lens group 110 is 200; the focal length of the focusing lens group 120 is 125, and the focal length of the collimating lens group 110 is 250; the focal length of the focusing lens group 120 is 150, and the focal length of the collimating lens group 110 is The focal length of the focusing lens group 120 is 150, and the focal length of the collimating lens group 110 is 200; the focal length of the focusing lens group 120 is 150, and the focal length of the collimating lens group 110 is 250; the focal length of the focusing lens group 120 is 200, and the focal length of the collimating lens group 110 is 200; the focal length of the focusing lens group 120 is 200, and the focal length of the collimating lens group 110 is 250; the focal length of the focusing lens group 120 is 250, and the focal length of the collimating lens group 110 is 250.

[0053] It is understandable that when the focal length F1 of the collimating lens group 110 is larger, the diameters of the collimating lens group 110 and the focusing lens group 120 are also increased accordingly, and it is necessary to ensure that the spot of the laser beam 400 does not exceed the boundary of the collimating lens group 110 and the focusing lens group 120. At the same time, the larger the focal length F1 of the collimating lens group 110 and the focal length F2 of the focusing lens group 120, the larger the size of the laser head 100. Therefore, while ensuring that the laser beam 400 has a larger divergence angle, the sizes of the focusing lens group 120 and the collimating lens group 110 need to be taken into consideration at the same time.

[0054] Furthermore, in order to achieve a better beam divergence angle A while taking into account the size of the collimating lens assembly 110 to better achieve the cutting of the connecting piece 520 of the battery pack 500, the ratio between the focal length of the focusing lens assembly 120 and the focal length of the collimating lens assembly 110 can be 0.5.

[0055] For example, the combination of the focusing lens group 120 and the collimating lens group 110 may include any one of the following groups:

[0056] The focal length of the focusing lens group 120 is 75, and the focal length of the collimating lens group 110 is 150; the focal length of the focusing lens group 120 is 100, and the focal length of the collimating lens group 110 is 200; the focal length of the focusing lens group 120 is 125, and the focal length of the collimating lens group 110 is 250.

[0057] In addition, according to the above content, it can be known that by controlling the ratio between the focal length of the focusing lens group 120 and the focal length of the collimating lens group 110 to be smaller, a larger beam divergence angle A (such as Figure 5 As shown), but at the same time, in order to ensure that there is sufficient spot energy density to cut the connecting piece 520 of the battery pack 500, the cutting defocus amount of the laser beam 400 needs to be controlled in a smaller range. Optionally, the cutting defocus amount of the laser beam 400 is -2mm~3mm. If the cutting defocus amount is further increased, the spot energy density will drop rapidly. At this time, in order to maintain the cutting effect, the power input of the laser 200 needs to be increased, which not only affects the cutting quality, but also increases the risk of surface damage to the battery 510.

[0058] Preferably, the cutting defocus of the laser beam 400 is 0 to 1 mm. The cutting defocus in this range can improve the cutting effect of the connecting piece 520 and avoid damaging the surface of the battery 510.

[0059] Furthermore, the cutting defocus amount of the laser beam 400 is 0. That is, the cutting focus of the laser beam 400 is located on the upper surface of the connecting piece 520 .

[0060] See also Figure 2 , the laser cutting method may further include:

[0061] The laser 200 is used to transmit the laser beam 400 to the laser head 100 through the transmission optical fiber 300. Specifically, the laser 200 is connected to the laser head 100 through the transmission optical fiber 300. The laser 200 generates a laser beam 400 which is transmitted to the laser head 100 through the transmission optical fiber 300. The laser beam 400 passes through the collimating lens group 110 and the focusing lens group 120 in the laser head 100 in sequence, and the laser beam 400 is finally emitted from the laser head 100 and irradiated on the connecting piece 520 of the battery pack 500.

[0062] Further, in some embodiments, the core diameter of the transmission optical fiber 300 is 50 μm to 300 μm. It is understandable that, since the ratio between the focal length of the focusing lens group 120 and the focal length of the collimating lens group 110 in the laser head 100 is set to 0 to 1, when the core diameter of the transmission optical fiber 300 is 50 μm to 300 μm, the laser beam 400 can obtain a larger beam divergence angle A while still having a smaller focal spot diameter, and the focus of the laser beam 400 and the nearby position can still obtain sufficient energy density to efficiently cut the connecting piece 520 of the battery pack 500.

[0063] Preferably, the core diameter of the transmission optical fiber 300 is 100 μm to 200 μm.

[0064] Further, in order to ensure the cutting effect and avoid damaging the outer surface of the battery 510, refer to Figure 5 , the spot diameter D of the laser beam 400 may be 25 μm to 300 μm. For example, the spot diameter of the laser beam 400 may be 25 μm, 34 μm, 50 μm, 100 μm, 150 μm, 180 μm, 200 μm, 250 μm or 300 μm, etc. Preferably, the spot diameter D of the laser beam 400400 is 50 μm to 200 μm.

[0065] The beam divergence angle A of the laser beam 400 may be 100 mrad to 550 mrad. For example, the beam divergence angle A of the laser beam 400 may be 100 mrad, 150 mrad, 200 mrad, 250 mrad, 300 mrad, 350 mrad, 400 mrad, 450 mrad, 500 mrad or 550 mrad.

[0066] See also Figure 2 The present application also provides a laser device for cutting the connecting piece 520 of the battery pack 500. The device includes a laser 200, a transmission optical fiber 300 and a laser head 100. The laser 200 is connected to the laser head 100 via the transmission optical fiber 300.

[0067] The ratio between the focal length of the focusing lens group 120 and the focal length of the collimating lens group 110 in the laser head 100 is 0 to 1. The cutting defocus amount when the laser head 100 emits the laser beam 400 for cutting is -2 mm to 3 mm, and the cutting defocus amount is the distance between the focus of the laser beam 400 and the upper surface of the connecting piece 520.

[0068] When the laser device of the present application cuts the connecting piece 520 of the battery pack 500, it can prevent the surface of the battery 510 below the connecting piece 520 of the battery pack 500 from being damaged by the laser, thereby ensuring that the cutting process is safe and reliable.

[0069] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of some applications should be included in the protection scope of some applications.

Claims

1. A laser cutting method, characterized in that: The following steps are involved: Place the battery pack in the cutting area; A laser head is used to emit a laser beam to cut the connecting piece of the battery pack, wherein the ratio between the focal length of the focusing lens group and the focal length of the collimating lens group in the laser head is 0 to 1, and the cutting defocus amount of the laser beam during cutting is -2 mm to 3 mm, and the cutting defocus amount is the distance between the focus of the laser beam and the upper surface of the connecting piece.

2. The laser cutting method according to claim 1, characterized in that: The ratio between the focal length of the focusing lens group of the laser head and the focal length of the collimating lens group is 0.3-1.

3. The laser cutting method according to claim 2, characterized in that: The ratio between the focal length of the focusing lens assembly and the focal length of the collimating lens assembly is 0.

5.

4. The laser cutting method according to claim 1, characterized in that: The cutting defocus amount during the laser beam cutting is 0 mm to 1 mm.

5. The laser cutting method according to claim 4, characterized in that: The cutting defocus amount during the laser beam cutting is 0.

6. The laser cutting method according to any one of claims 1 to 5, characterized in that: The method further comprises: A laser is used to transmit a laser beam to a laser head through a transmission optical fiber, wherein the core diameter of the transmission optical fiber is 50 μm to 300 μm.

7. The laser cutting method according to claim 6, characterized in that: The spot diameter of the laser beam is 25 μm to 300 μm.

8. The laser cutting method according to claim 6, characterized in that: The beam divergence angle of the laser beam is 100 mrad to 550 mrad.

9. A laser cutting method, characterized in that: The following steps are involved: Placing a battery pack in a cutting area, wherein the battery pack includes a plurality of batteries and a connecting piece for connecting the plurality of batteries; A laser head is used to emit a laser beam to cut the connecting piece corresponding to the gap between the batteries, wherein the ratio between the focal length of the focusing lens group and the focal length of the collimating lens group in the laser head is 0 to 1, and the cutting defocus amount of the laser beam during cutting is -2 mm to 3 mm, and the cutting defocus amount is the distance between the focus of the laser beam and the upper surface of the connecting piece.

10. A laser device for cutting a connecting piece of a battery pack, characterized in that: It includes a laser, a transmission optical fiber and a laser head, wherein the laser is connected to the laser head through the transmission optical fiber; wherein, The ratio between the focal length of the focusing lens group and the focal length of the collimating lens group in the laser head is 0 to 1; The cutting defocus amount when the laser head emits a laser beam for cutting is -2mm to 3mm, and the cutting defocus amount is the distance between the focus of the laser beam and the upper surface of the connecting piece.

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