Gas auxiliary equipment for laser welding and laser welding systems

Abstract

The present disclosure discloses a gas-assist device (1) for laser welding, the gas-assist device (1) including an auxiliary gas unit (11) configured to supply an auxiliary gas, such as a shielding gas, to a welding point and having an auxiliary gas nozzle (111) therefor, and a fume suction unit (12) configured to suction fumes generated during laser welding and having a fume suction port (121) therefor, wherein the auxiliary gas nozzle (111) includes a first slit-shaped opening (1111), the fume suction port (121) includes a second slit-shaped opening (1211), the fume suction unit (12) is at least partially attached to the auxiliary gas unit (11), and in an operating state of the gas-assist device (1), the second slit-shaped opening (1211) is at least partially positioned above the first slit-shaped opening (1111). A corresponding laser welding system is also disclosed. According to some exemplary embodiments, the increased level of integration of the device can be used to simplify the structure, while also increasing suction performance and weld joint quality.

Description

[Technical Field]

[0001] The present disclosure relates to a gas assist device for laser welding and a corresponding laser welding system.

[0002] Background technology Lithium batteries are widely used in various electronic devices and transportation vehicles, such as electric vehicles, due to their multiple advantages, including high specific energy, long cycle life, low self-discharge, no memory effect, and no pollution. Lithium batteries used in vehicles can also be called power batteries.

[0003] A lithium battery typically includes a battery case body and a battery case lid plate fixed thereto. Currently, the battery case lid plate is typically fixedly joined to the battery case body by a laser welding process.

[0004] During laser welding, partial gas shielding is required during the welding process to prevent oxidation and reduce porosity. Existing laser welding processes mainly involve welding the battery case cover plate to the battery case body using a fixed welding head, while simultaneously spraying shielding gas from a nozzle on the laser head. However, this method is not suitable for sealing the periphery of the battery case cover plate and the battery case body.

[0005] For this reason, a proposal has been made to use a separate device for providing shielding gas in conjunction with a scanner welding head with high welding efficiency. For example, the applicant of the present disclosure has proposed a shielding gas providing device for injecting shielding gas into the peripheral edge of a battery case cover plate (see, for example, Chinese Patent Application Publication No. 112171054, the contents of which are incorporated herein by reference).

[0006] Another issue is the need to extract the fumes generated during the welding process, as they are not only harmful to the operator's health but also directly affect the formation of the weld joint. For example, during the formation of the weld joint, the fumes can affect the propagation of the laser, reducing the weld joint's quality.

[0007] Currently, a separate suction pipe is usually provided to extract the fumes, but if not properly positioned, this method may not cover the entire welding path and may leave a suction gap, which may further affect the injection of the shielding gas, for example, impairing the uniformity of the shielding gas, especially the laminar flow performance, and thus adversely affecting the quality of the welded joint.

[0008] Apart from these, there are other possible problems in reality, so there is a need to improve the existing laser welding equipment in order to improve the laser welding process.

[0009] Summary of the Invention It is therefore an object of the present disclosure to provide an improved gas assist device for laser welding and a corresponding laser welding system.

[0010] According to a first aspect of the present disclosure, there is provided a gas assist device for laser welding, the gas assist device including: an auxiliary gas unit configured to supply an auxiliary gas such as a shielding gas to a welding point and having an auxiliary gas nozzle therefor; and a fume suction unit configured to suction fumes generated during laser welding and having a fume suction port therefor, wherein the auxiliary gas nozzle includes a first slit-shaped opening, the fume suction port includes a second slit-shaped opening, the fume suction unit is at least partially attached to the auxiliary gas unit, and in an operating state of the gas assist device, the second slit-shaped opening is at least partially positioned above the first slit-shaped opening.

[0011] According to any embodiment of the present disclosure, the gas assist device is configured in an annular shape.

[0012] According to any embodiment of the present disclosure, the gas assist device includes a flow direction restricting structure disposed between the assist gas nozzle and the fume suction port, the flow direction restricting structure configured to direct the fumes to flow toward the fume suction port.

[0013] According to any embodiment of the present disclosure, the first slit-shaped opening and the second slit-shaped opening extend in parallel.

[0014] According to any embodiment of the present disclosure, the gas assist device is configured to have an upper opening and a lower opening facing opposite the upper opening, the upper opening being larger than the lower opening, and the assist gas nozzle is disposed at the edge of the lower opening.

[0015] According to any embodiment of the present disclosure, the fume suction port is provided inside the gas assist device.

[0016] According to any embodiment of the present disclosure, the flow direction restricting structure is configured to direct the fumes to flow toward the fume suction port in a direction between 1° and 9°, for example 5°, relative to the horizontal.

[0017] According to any embodiment of the present disclosure, the gas assist device is configured to have an inner and / or outer side that extends at least partially outward in a vertically sloping manner from the bottom surface to the top surface in an operating state.

[0018] According to any embodiment of the present disclosure, the fume suction port is positioned substantially centrally inside in the vertical direction.

[0019] According to any embodiment of the present disclosure, the auxiliary gas unit is configured at least partially as an outer ring structure, and the fume suction unit is configured at least partially as an inner ring structure, the inner ring structure being embedded within the outer ring structure.

[0020] According to any embodiment of the present disclosure, the first slit-shaped opening is configured to surround a circle.

[0021] According to any embodiment of the present disclosure, the second slit-shaped opening is configured to surround a circle.

[0022] According to any embodiment of the present disclosure, the fume suction port is formed on the inner ring structure.

[0023] According to any embodiment of the present disclosure, the fume suction port opens in a manner that slopes downward and inward.

[0024] According to any embodiment of the present disclosure, the auxiliary gas nozzles open in a downwardly inwardly sloping manner.

[0025] According to any embodiment of the present disclosure, the auxiliary gas nozzle is configured to emit the auxiliary gas in a laminar flow manner.

[0026] According to any embodiment of the present disclosure, the fume suction port has substantially the same orientation as that of the auxiliary gas nozzle.

[0027] According to any embodiment of the present disclosure, the flow direction restricting structure includes a first protrusion.

[0028] According to any embodiment of the present disclosure, the interior of the gas assist device includes a second protrusion for defining a suction passage in fluid communication with the fume suction port.

[0029] According to any embodiment of the present disclosure, the first protrusion is configured to have a triangular cross section.

[0030] According to any embodiment of the present disclosure, the interior of the gas assist device is configured to define a groove between the first protrusion and the second protrusion, whereby fumes pass through the groove and into the fume suction port.

[0031] According to any embodiment of the present disclosure, the fume suction port is located at the lower edge of the second protrusion.

[0032] According to any embodiment of the present disclosure, the second protrusion is formed to have an inclined slope at its inner lower end region toward the fume suction port.

[0033] According to any embodiment of the present disclosure, the second protrusion extends to the upper edge of the gas assist device.

[0034] According to any embodiment of the present disclosure, a first side of the triangular cross section extends from a region adjacent the auxiliary gas nozzle to the groove to form an inner surface of the first protrusion.

[0035] According to any embodiment of the present disclosure, the second side of the triangular cross-section defines a groove.

[0036] According to any embodiment of the present disclosure, the fume suction port faces the groove.

[0037] According to any embodiment of the present disclosure, the first protrusion is configured in an annular shape.

[0038] According to any embodiment of the present disclosure, the second protrusion is configured in an annular shape.

[0039] According to an alternative embodiment of the present disclosure, the groove is configured in an annular shape.

[0040] According to any embodiment of the present disclosure, the gas assist device further includes at least one auxiliary gas inlet port in fluid communication with the auxiliary gas nozzle through the auxiliary gas flow path.

[0041] According to any embodiment of the present disclosure, the gas assist device further includes at least one fume exhaust port in fluid communication with the fume suction port.

[0042] According to any embodiment of the present disclosure, the gas assist device further includes an upper surface and a beveled edge disposed adjacent to and outwardly of the upper surface and sloping downwardly away from the upper surface.

[0043] According to any embodiment of the present disclosure, a uniform gas distribution structure is provided in the auxiliary gas flow path to enable the auxiliary gas to be uniformly ejected from the auxiliary gas nozzle.

[0044] According to any embodiment of the present disclosure, the at least one auxiliary gas inlet port includes at least two auxiliary gas inlet ports evenly spaced circumferentially on the beveled edge.

[0045] According to any embodiment of the present disclosure, the at least one fume exhaust port includes at least two fume exhaust ports evenly spaced circumferentially on the upper surface.

[0046] According to any embodiment of the present disclosure, the uniform gas distribution structure is configured as a grid structure and / or an orifice plate structure.

[0047] According to any embodiment of the present disclosure, the top surface is configured in an annular shape and the beveled edge surrounds the periphery of the top surface.

[0048] According to any embodiment of the present disclosure, the gas assist device is configured to be suitable for welding a battery case lid plate of a lithium battery.

[0049] According to any embodiment of the present disclosure, the gas assist device is at least partially fabricated from metal by 3D printing techniques, particularly by selective laser melt printing techniques.

[0050] According to any embodiment of the present disclosure, the gas assist device is formed by joining together multiple modules.

[0051] According to any embodiment of the present disclosure, the fume suction unit is at least partially removably attached to the auxiliary gas unit.

[0052] According to any embodiment of the present disclosure, the gas assist device is integrally formed.

[0053] According to a second aspect of the present disclosure, there is provided a laser welding system, wherein the laser welding system includes at least a gas assist device according to any of the above embodiments.

[0054] According to some exemplary embodiments of the present disclosure, the increased level of integration of the device can be used to simplify the structure, while also increasing suction performance and weld joint quality.

[0055] The principles, features, and advantages of the present disclosure may be better understood from a more detailed description of the disclosure, taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0056] [Figure 1] FIG. 1 is a top view illustrating a gas assist device for laser welding according to an exemplary embodiment of the present disclosure. [Figure 2] FIG. 1 is a perspective view illustrating a gas assist device for laser welding according to an exemplary embodiment of the present disclosure. [Figure 3] 3 is a perspective view showing the gas assist device shown in FIG. 2, taken from a different viewpoint than FIG. 2. FIG. [Figure 4] FIG. 2 is a cross-sectional view of a gas assist device for laser welding according to an exemplary embodiment of the present disclosure to illustrate its internal structure. [Figure 5] FIG. 1 is a perspective cross-sectional view illustrating a gas assist device for laser welding according to an exemplary embodiment of the present disclosure. [Figure 6]6 is a perspective cross-sectional view showing the gas assist device shown in FIG. 5, taken from a different viewpoint than FIG. 5.

[0057] Detailed Description of the Embodiments In order to more clearly understand the technical problems to be solved, the technical solutions, and the advantageous technical effects of the present disclosure, the present disclosure will be described in more detail below in conjunction with the drawings and several exemplary embodiments. It should be understood that the specific embodiments described herein are intended to illustrate the present disclosure, rather than limiting the protection scope of the present disclosure.

[0058] For clarity of explanation, directional or orientation terms may be used herein, however, unless otherwise specified, any directional or orientation term refers to its use in a typical situation, but this does not imply that the directional or orientation applies to all scenes.

[0059] FIG. 1 illustrates a top view of a gas assist device for laser welding according to an exemplary embodiment of the present disclosure.

[0060] FIG. 2 illustrates a perspective view of a gas assist device for laser welding according to an exemplary embodiment of the present disclosure.

[0061] FIG. 3 shows a perspective view of the gas assist device shown in FIG. 2 from a different viewpoint than that of FIG.

[0062] FIG. 4 shows a cross-sectional view of a gas assist device for laser welding according to an exemplary embodiment of the present disclosure to illustrate its internal structure.

[0063] FIG. 5 illustrates a perspective cross-sectional view of a gas assist device for laser welding according to an exemplary embodiment of the present disclosure.

[0064] FIG. 6 shows a perspective cross-sectional view of the gas assist device shown in FIG. 5, taken from a different perspective than that of FIG.

[0065] Before starting the description, it should first be noted that some reference symbols are not marked in all views due to the viewing angle and space constraints on the marking of the reference symbols. Therefore, when referring to the description, multiple views may be referenced simultaneously for ease of understanding, but this does not mean that each of the features must appear in all embodiments.

[0066] 1 to 6 , one embodiment of the present disclosure provides a gas auxiliary device 1 for laser welding, including an auxiliary gas unit 11 configured to supply an auxiliary gas such as a shielding gas to a welding point and having an auxiliary gas nozzle 111 therefor, and a fume suction unit 12 configured to suction fumes generated during laser welding and having a fume suction port 121 therefor, wherein the auxiliary gas nozzle 111 includes a first slit-shaped opening 1111, the fume suction port 121 includes a second slit-shaped opening 1211, the fume suction unit 12 is at least partially attached to the auxiliary gas unit 11, and in an operating state of the gas auxiliary device 1, the second slit-shaped opening 1211 is at least partially disposed above the first slit-shaped opening 1111. In particular, such attachment allows the fume suction unit 12 to be fixed in a position relative to the auxiliary gas unit 11 and therefore to move together therewith.

[0067] Here, the term "gas assist device" includes the control and regulation of gas during the welding process, and mainly includes the supply of shielding gas by blowing and the suction of fumes.

[0068] This gas assist device is particularly suitable for use in laser welding of lithium battery cases. During the laser welding process, the application of an assist gas allows the laser welding to be performed under the desired conditions. The assist gas can not only function as a shielding gas to prevent oxidation and reduce porosity, but also affect the appearance of the weld joint. Therefore, for those skilled in the art, the assist gas can be any gas, such as an inert gas, that is useful for achieving the desired weld quality.

[0069] As shown in Figures 1-3 and also in Figures 4-6, the gas-assist device 1 is in an assembled state. In this assembled state, the gas-assist device 1 is in the shape of a closed ring having an upper opening 13 and a lower opening 14. For example, when welding a battery case cover plate to a battery case body, the lower opening may be slightly larger than the battery, for example, by about 10 mm in the circumferential direction. A circle of auxiliary gas nozzles 111 is provided on the inner lower edge of the closed ring. For laser welding of a lithium battery case, the welding point between the battery case body and the battery case cover plate is positioned at the lower opening 14 adjacent to the auxiliary gas nozzle 111, so that auxiliary gas can be supplied to the welding point during the laser welding process and assist the laser welding process to achieve good weld quality. Simultaneously, during the welding process, fumes are collected in a cavity in the central region of the gas-assist device 1 and are sucked from above through the fume suction opening 121. For this reason, the fume suction port 121 is provided inside the gas auxiliary device 1. Additionally, to prevent the suction of fumes from affecting the protection of the welding points by the auxiliary gas, it is necessary to minimize the effect on the intended flow pattern of the auxiliary gas, and in particular to avoid turbulent flow of the auxiliary gas. For this reason, the fume suction port 121 is configured to suck in fumes in a manner that does not affect the desired flow pattern of the auxiliary gas, in particular the laminar flow jet of the auxiliary gas. Therefore, the relative arrangement and positional relationship between the auxiliary gas nozzle 111 and the fume suction port 121 is important.

[0070] According to an exemplary embodiment of the present disclosure, as shown in FIGS. 4, 5, and 6, the gas assistance device 1 includes a flow direction restricting structure 17 disposed between the auxiliary gas nozzle 111 and the fume suction port 121, and the flow direction restricting structure 17 is configured to direct the fumes to flow toward the fume suction port 121 in direction A (see FIG. 5).

[0071] According to an exemplary embodiment of the present disclosure, in the operating state, the direction A is at an angle of 1° to 9°, for example 5°, with respect to the horizontal direction. In this way, fumes can be sucked in a substantially horizontal direction without disrupting the downward flow of the shielding gas.

[0072] According to an exemplary embodiment of the present disclosure, the first slit-shaped opening 1111 and the second slit-shaped opening 1211 extend parallel to each other, so that the first slit-shaped opening 1111 injects shielding gas downward in a laminar manner, while the second slit-shaped opening 1211 smoothly sucks fumes upward without adversely affecting the injection of shielding gas downward.

[0073] According to an exemplary embodiment of the present disclosure, the gas assist device 1 is configured to have an inner and / or outer side that extends at least partially outward in a vertically inclined manner from the bottom surface to the top surface in an operating state. In particular, it slopes outward from the bottom surface to the top surface all around, whereby the upper opening is larger than the lower opening.

[0074] According to an exemplary embodiment of the present disclosure, the fume suction port 121 is positioned substantially centrally inside in the vertical direction.

[0075] According to an exemplary embodiment of the present disclosure, the auxiliary gas unit 11 is configured at least partially as an outer ring structure, and the fume suction unit 12 is configured at least partially as an inner ring structure, which is embedded in the outer ring structure. Preferably, the fume suction port 121 is formed on the inner ring structure.

[0076] According to an exemplary embodiment of the present disclosure, the first slit-shaped opening 1111 is configured to surround a circle. In particular, to weld a lithium battery case, it is necessary to weld the battery case cover plate around the entire circumference of the battery case body. Therefore, the surrounding first slit-shaped opening 1111 allows for the injection of auxiliary gas, particularly shielding gas, to each welding point.

[0077] Similarly, the second slit-shaped opening 1211 is also configured to surround a circle, thereby allowing suction from all sides.

[0078] 4, 5, and 6, according to an exemplary embodiment of the present disclosure, the auxiliary gas nozzle 111 opens in a manner inclined downward and inward, whereby the auxiliary gas is sprayed from the auxiliary gas nozzle 111 in a direction B. During welding, the welding point is located at the edge of the lower opening, so that the auxiliary gas nozzle 111, which opens in a manner inclined downward and inward, can immediately spray the auxiliary gas toward the welding point.

[0079] Similarly, the fume suction port 121 also opens in a manner that slopes downward and inward. Preferably, the fume suction port 121 has substantially the same orientation as that of the auxiliary gas nozzle 111.

[0080] According to an exemplary embodiment of the present disclosure, the flow direction restricting structure 17 includes a first protrusion 171 .

[0081] In an exemplary embodiment of the present disclosure, the interior of the gas assist device 1 includes a second protrusion 15 for defining a suction passage 123 in fluid communication with the fume suction port 121 .

[0082] Preferably, the first protrusion 171 and the second protrusion 15 have different inclination angles. According to an exemplary embodiment of the present disclosure, the first protrusion 171 has a larger inclination angle relative to the horizontal plane than that of the second protrusion 15.

[0083] According to an exemplary embodiment of the present disclosure, as shown in FIG. 5, the first protrusion 171 is configured to have a triangular cross section.

[0084] According to an exemplary embodiment of the present disclosure, the inside of the gas assist device 1 is configured to define a groove 16 between the first protrusion 171 and the second protrusion 15, whereby fumes pass through the groove 16 and enter the fume suction port 121.

[0085] According to an exemplary embodiment of the present disclosure, the fume suction port 121 is disposed at the lower edge of the second protrusion 15. In particular, the fume suction opening 121 is disposed facing the groove 16. In this case, the fumes first enter the groove 16 and then are redirected to the fume suction port 121.

[0086] According to an exemplary embodiment of the present disclosure, the second protrusion 15 is formed to have a slope 151 inclined toward the fume suction port 121 at its inner lower end region.

[0087] According to an exemplary embodiment of the present disclosure, the second protrusion 15 extends to the upper edge of the gas assist device 1 .

[0088] According to an exemplary embodiment of the present disclosure, a first side 1711 of the triangular cross-section of the first step 171 extends from the area adjacent the auxiliary gas nozzle 111 to the groove 16 to form the inner surface of the first protrusion 171. In particular, a second side 1712 of the triangular cross-section defines the groove 16.

[0089] According to an exemplary embodiment of the present disclosure, the first protrusion 171 is configured in an annular shape. Similarly, the second protrusion 15 is also configured in an annular shape. In this case, the groove 16 may also be configured in an annular shape.

[0090] 4 and 6, the gas assist device 1 further includes at least one auxiliary gas inlet port 113 in fluid communication with the auxiliary gas nozzle 111 through the auxiliary gas flow path 112. The auxiliary gas inlet port 113 can receive auxiliary gas from an auxiliary gas source (not shown), for example, through a supply line (not shown), preferably a hose.

[0091] According to an exemplary embodiment of the present disclosure, the auxiliary gas flow path 112 is provided with a uniform gas distribution structure 115 to enable the auxiliary gas to be uniformly ejected from the auxiliary gas nozzle 111. This is very important for forming a laminar flow of the auxiliary gas.

[0092] According to an exemplary embodiment of the present disclosure, the uniform gas distribution structure 115 is configured as a grid structure and / or an orifice plate structure. The grid structure and / or the orifice plate structure not only allows the auxiliary gas to diffuse and flow to the auxiliary gas nozzles 111, thereby allowing the auxiliary gas to be uniformly ejected from the auxiliary gas nozzles 111, but also increases the flow path of the auxiliary gas, causing the auxiliary gas to repeatedly come into contact with different portions of the grid structure and / or the orifice plate structure. This is advantageous for heat dissipation of the auxiliary gas when cooling is required, and is also beneficial for laser welding.

[0093] According to an exemplary embodiment of the present disclosure, the gas assist device 1 further includes at least one fume exhaust port 124 in fluid communication with the fume suction port 121. The fume exhaust port 124 may be connected to a suction pump (not shown), for example, by a hose.

[0094] According to an exemplary embodiment of the present disclosure, and with reference to FIGS. 1-3 , for example, gas assist device 1 further includes upper surface 125 and sloped edge 114 disposed adjacent to and outwardly of upper surface 125 and sloping downwardly away from upper surface 125.

[0095] According to an exemplary embodiment of the present disclosure, the at least one auxiliary gas inlet port 113 includes at least two auxiliary gas inlet ports evenly spaced around the circumferential direction on the beveled edge 114. While the embodiment shown in the drawings includes two auxiliary gas inlet ports arranged opposite each other, those skilled in the art will understand that this is not a limitation. The supply of auxiliary gas to the auxiliary gas inlet ports may be selectively controlled according to needs; preferably, different auxiliary gas inlet ports correspond to auxiliary gas nozzles in different regions, so that the supply of auxiliary gas to the welding point can be selectively controlled depending on the welding point.

[0096] According to an exemplary embodiment of the present disclosure, the at least one fume exhaust port 124 includes at least two fume exhaust ports evenly spaced circumferentially on the upper surface 125. The illustrated embodiment includes four fume exhaust ports. Similarly, the fume exhaust ports in different regions may be selectively controlled to achieve a suction effect on the corresponding regions.

[0097] According to an exemplary embodiment of the present disclosure, the upper surface 125 is configured as an annular shape, and the beveled edge 114 surrounds the periphery of the upper surface 125 and is therefore also annular.

[0098] According to an exemplary embodiment of the present disclosure, the gas assist device 1 is at least partially fabricated from metal by 3D printing techniques, particularly by selective laser melting printing techniques. In particular, the entire gas assist device 1 is integrally formed.

[0099] However, those skilled in the art will understand that plastic materials may be considered depending on the different thermal requirements of welding. Manufacturing using 3D printing technology can help process more complex internal structures. Furthermore, 3D printing technology allows for flexible processing and adjustment of different shapes of battery case cover plates.

[0100] Of course, the gas assist device 1 may also be formed by joining several modules together.

[0101] According to an exemplary embodiment of the present disclosure, the fume suction unit 12 is at least partially removably attached to the auxiliary gas unit 11. In particular, the fume suction unit 12 may be attached to the auxiliary gas unit 11 as an inner ring structure.

[0102] According to the present disclosure, welding can be performed using a scanner welding head as well as a fixed welding head.

[0103] In another aspect of the present disclosure, a laser welding system is provided, wherein the laser welding system includes at least a gas assist apparatus according to any of the exemplary embodiments described above.

[0104] It is obvious to those skilled in the art that the technical concept of the present disclosure is not limited to laser welding of lithium battery cases, but instead can be applied to welding of structures of any other shape, and is not limited to a completely circular arrangement, but can be adjusted according to the actual welding needs.

[0105] While particular embodiments of the present disclosure have been described in detail, these have been presented for purposes of illustration only and should not be construed as limiting the scope of the disclosure. Various substitutions, changes, and modifications can be devised without departing from the spirit and scope of the disclosure.

Claims

1. A gas assist device (1) for laser welding, The gas auxiliary device (1) comprises: an auxiliary gas unit (11) configured to supply an auxiliary gas such as a shielding gas to a welding point and having an auxiliary gas nozzle (111) for this purpose; a fume suction unit (12) configured to suction fumes generated during laser welding and having a fume suction port (121) for that purpose; The gas-assistance device (1), characterized in that the auxiliary gas nozzle (111) includes a first slit-shaped opening (1111), the fume suction port (121) includes a second slit-shaped opening (1211), the fume suction unit (12) is at least partially attached to the auxiliary gas unit (11), and in an operating state of the gas-assistance device (1), the second slit-shaped opening (1211) is at least partially positioned above the first slit-shaped opening (1111).

2. the gas assist device (1) is configured in an annular manner and / or the gas auxiliary device (1) comprises a flow direction restricting structure (17) provided between the auxiliary gas nozzle (111) and the fume suction port (121), the flow direction restricting structure (17) being configured to direct fumes to flow towards the fume suction port (121); and / or 2. The gas-assisted device (1) for laser welding according to claim 1, wherein the first slit-shaped opening (1111) and the second slit-shaped opening (1211) extend parallel to each other.

3. the gas-assist device (1) is configured with an upper opening (13) and a lower opening (14) facing opposite the upper opening (13), the upper opening (13) being larger than the lower opening (14), and the assist gas nozzle (111) being arranged at the edge of the lower opening (14); and / or The fume suction port (121) is located inside the gas assist device (1), and / or 3. The gas-assisted device (1) for laser welding according to claim 2, wherein the flow direction restricting structure (17) is configured to direct the fumes to flow toward the fume suction port (121) in a direction (A) of 1 to 9 degrees, for example, 5 degrees, relative to the horizontal.

4. the gas-assist device (1) is configured to have an inner side and / or an outer side that extend at least partially outward in a vertically inclined manner from the bottom surface to the top surface in an operating state; and / or 4. The gas-assisted device (1) for laser welding according to claim 3, wherein the fume suction port (121) is arranged substantially centrally inside in the vertical direction.

5. the auxiliary gas unit (11) is configured at least partially as an outer ring structure, the fume suction unit (12) is configured at least partially as an inner ring structure, the inner ring structure being embedded in the outer ring structure, and / or said first slit-like opening (1111) is configured to surround a circle; and / or 5. The gas-assisted device (1) for laser welding according to claim 2, wherein the second slit-shaped opening (1211) is configured to surround a circle.

6. The fume suction port (121) is formed on the inner ring structure, and / or The fume suction port (121) opens downwards and inwards, and / or the auxiliary gas nozzle (111) opens downwards in an inwardly sloping manner, and / or 6. The gas assist device (1) for laser welding according to claim 5, wherein the assist gas nozzle (111) is configured to emit the assist gas in a laminar flow manner.

7. the fume suction port (121) has substantially the same orientation as that of the auxiliary gas nozzle (111); and / or The flow direction restricting structure (17) includes a first protrusion (171); and / or 7. The gas-assisted device (1) for laser welding according to claim 2, wherein an inside of the gas-assisted device (1) is provided with a second protrusion (15) for defining a suction passage (123) fluidly connected to the fume suction port (121).

8. said first protrusion (171) is configured to have a triangular cross section; and / or 8. The gas-assisted device (1) for laser welding according to claim 7, wherein an inside of the gas-assisted device (1) is configured to define a groove (16) between the first protrusion (171) and the second protrusion (15), whereby fumes pass through the groove (16) and flow into the fume suction port (121).

9. the fume suction port (121) is located at the lower edge of the second protrusion (15); and / or the second protrusion (15) is formed with an inclined slope (151) in its inner lower end region towards the fume suction port (121); and / or Gas-assisted device (1) for laser welding according to claim 7 or 8, characterized in that the second protrusion (15) extends to an upper edge of the gas-assisted device (1).

10. a first side (1711) of said triangular cross section extending from the area adjacent said auxiliary gas nozzle (111) to said groove (16) and forming an inner surface of said first protrusion (171); and / or a second side (1712) of said triangular cross-section defining said groove (16); and / or 9. The gas-assisted device (1) for laser welding according to claim 8, wherein the fume suction port (121) faces the groove (16).

11. the first protrusion (171) is configured in an annular shape; and / or the second projection (15) is configured in an annular shape; and / or 11. The gas-assisted device (1) for laser welding according to claim 8, wherein the groove (16) is configured annularly.

12. the gas assist device (1) further comprises at least one auxiliary gas inlet port (113) in fluid communication with the auxiliary gas nozzle (111) through an auxiliary gas flow passage (112); and / or 12. The gas-assisted device (1) for laser welding according to claim 1, further comprising at least one fume exhaust port (124) fluidly connected to the fume suction port (121).

13. The gas-assist device (1) further comprises an upper surface (125) and a sloping edge (114) disposed adjacent to and outside the upper surface (125) and sloping downwardly away from the upper surface (125); and / or 13. The gas assist device (1) for laser welding according to claim 1, wherein a gas uniform distribution structure (115) is provided in the auxiliary gas flow path (112) to enable the auxiliary gas to be uniformly sprayed from the auxiliary gas nozzle (111).

14. the at least one auxiliary gas inlet port (113) comprises at least two auxiliary gas inlet ports evenly spaced circumferentially on said beveled edge (114); and / or the at least one fume exhaust port (124) comprises at least two fume exhaust ports evenly spaced circumferentially on said upper surface (125); and / or the gas uniform distribution structure (115) is configured as a grid structure and / or an orifice plate structure; and / or 14. The gas-assisted device (1) for laser welding according to claim 13, wherein the upper surface (125) is configured annularly and the beveled edge (114) surrounds the periphery of the upper surface (125).

15. The gas assist device (1) is configured to be suitable for welding the battery case lid plate of a lithium battery, and / or said gas assist device (1) is at least partly made from metal by 3D printing techniques, in particular by selective laser melting printing techniques; and / or said gas assist device (1) is formed by joining together several modules; and / or the fume suction unit (12) is at least partially removably attached to the auxiliary gas unit (11), or 15. The gas-assist device (1) for laser welding according to claim 1, wherein the gas-assist device (1) is formed integrally.

16. 16. A laser welding system, the laser welding system including at least a gas assist device according to any one of claims 1 to 15.

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