Dust removal mechanism for laser welding

Abstract

This utility model relates to the technical field of lithium battery production equipment, and discloses a dust removal mechanism for laser welding, including a dust removal hood, a protective gas nozzle, a negative pressure dust removal interface, and a ventilation structure. The dust removal hood has a dust removal chamber, a first side and a second side opposite to each other along a first direction, and a third side and a fourth side opposite to each other along a second direction. The first side has a first through hole communicating with the dust removal chamber, and the second side has a second through hole communicating with the dust removal chamber. The first through hole is directly opposite the second through hole, and the first and second through holes are used for laser transmission. The first direction is perpendicular to the second direction. The protective gas nozzle and the ventilation structure are located on the third side, and the negative pressure dust removal interface is located on the fourth side. The ventilation structure has an air duct connecting the dust removal chamber and the outside of the dust removal hood. The air outlet of the protective gas nozzle is located inside the dust removal chamber and faces the second through hole. This utility model is more conducive to the removal and collection of dust particles during laser welding, thereby improving the dust removal effect.

Description

Technical Field

[0001] This utility model relates to the field of battery production equipment technology, and in particular to a dust removal mechanism for laser welding. Background Technology

[0002] In the production of lithium batteries, laser welding is frequently used. During this process, nitrogen protection is usually required to prevent the weld joints from oxidizing. At the same time, dust removal is required to collect and remove the welding slag that is scattered during welding.

[0003] Existing laser welding dust removal structures generally include a dust hood, a protective gas input pipe located on the opposite side of the dust hood, and a negative pressure dust removal pipe. The protective gas input pipe is positioned near the upper end of the dust hood, allowing the protective gas to enter from above and be drawn out through the negative pressure dust removal pipe on the side. The laser passes through a through-hole at the top of the dust hood to weld the workpiece below. While existing laser welding dust removal structures can remove welding slag to some extent, the slag removal effect is limited, and welding slag inevitably remains in the welding area. Utility Model Content

[0004] The purpose of this utility model embodiment is to provide a dust removal mechanism for laser welding, which can improve the dust removal effect.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A dust removal mechanism for laser welding is provided, comprising:

[0007] A dust removal hood has a dust removal chamber, and has a first side and a second side opposite to each other along a first direction, as well as a third side and a fourth side opposite to each other along a second direction. The first side is provided with a first through hole communicating with the dust removal chamber, and the second side is provided with a second through hole communicating with the dust removal chamber. The first through hole is directly opposite the second through hole. The first through hole and the second through hole are used for laser to pass through, and the first direction is perpendicular to the second direction.

[0008] The device includes a protective gas nozzle, a negative pressure dust removal interface, and a ventilation structure. The protective gas nozzle and the ventilation structure are located on the third side, and the negative pressure dust removal interface is located on the fourth side. The ventilation structure has an air duct connecting the dust removal chamber and the outside of the dust removal hood. The air outlet of the protective gas nozzle is located inside the dust removal chamber and faces the second through hole.

[0009] As a further embodiment of the dust removal mechanism for laser welding, the protective gas nozzle is located between the ventilation structure and the second side along the first direction.

[0010] As a further embodiment of the dust removal mechanism for laser welding, the second through hole is adjacent to the area to be welded, the protective gas nozzle is inclined toward the center of the second through hole, and the air duct of the ventilation structure is inclined toward the center of the second through hole.

[0011] As a further embodiment of the dust removal mechanism for laser welding, the negative pressure dust removal interface includes a conical portion and an interface portion. The conical portion has a first end and a second end opposite to each other along the second direction. The fourth side of the dust removal hood is open. The first end is connected to the fourth side of the dust removal hood. The conical portion has a conical cavity communicating with the dust removal chamber. The second end is connected to the interface portion. The interface portion has a dust removal port communicating with the conical cavity. The cross-section of the first end is larger than the cross-section of the second end.

[0012] As a further embodiment of the dust removal mechanism for laser welding, the interface is circular with a radius of r1, the dust hood is rectangular, the height of the dust hood along the first direction is h, and the width of the dust hood along the third direction is L. Then (L*h / (2*π))^0.5≤r1≤(L*h / π)^0.5, and the first direction, the second direction, and the third direction are perpendicular to each other.

[0013] As a further embodiment of the dust removal mechanism for laser welding, the radius of the first through hole is r2, and the radius of the laser beam at the point where the outer end face of the first through hole is tangent to the laser beam passing through the first through hole is r3. Then r3*1.05≤r2≤r3*1.5.

[0014] As a further embodiment of the dust removal mechanism for laser welding, the ventilation structure is a louver, the louver having a plurality of spaced air ducts along the first direction, and the two ends of the louver along a third direction being fixedly connected to the two side walls of the dust removal hood opposite to each other along the third direction, the first direction, the second direction and the third direction being perpendicular to each other.

[0015] As a further embodiment of the dust removal mechanism for laser welding, the protective gas nozzle includes a nozzle interface, a nozzle body, and a porous medium. The nozzle body is connected to the nozzle interface and is inclined toward the center of the second through hole. The air outlet of the nozzle body extends into the dust removal hood. The nozzle body has a cavity that communicates with the nozzle interface and the air outlet. The porous medium is installed in the nozzle body.

[0016] As a further embodiment of the dust removal mechanism for laser welding, the nozzle body includes a first transition tube and a second transition tube connected together. The end of the first transition tube away from the second transition tube is connected to the nozzle interface, and the end of the second transition tube away from the first transition tube is the air outlet. The first transition tube has a first conical chamber that gradually narrows toward the nozzle interface, and the second transition tube has a second conical chamber that gradually narrows toward the first transition tube. The porous medium is installed in the second conical chamber, and the outer periphery of the porous medium is attached to the cavity wall of the second conical chamber.

[0017] As a further embodiment of the dust removal mechanism for laser welding, it also includes a fixed plate, an annular pressure plate, and a mounting base. The second side of the dust removal hood is attached to the fixed plate. The fixed plate has a third through hole corresponding to the second through hole. The protective gas nozzle is mounted on the fixed plate through the mounting base. The mounting base and the dust removal hood are spaced apart along the second direction. The annular pressure plate is arranged around the third through hole.

[0018] Beneficial effects:

[0019] This invention places the protective gas nozzle and ventilation structure on the third side of the dust removal hood, while the negative pressure dust removal interface is located on the fourth side opposite to the third side. During laser welding, the protective gas nozzle blows protective gas into the area of ​​the second through hole through its blowing port to protect the welding area. When the negative pressure dust removal interface is connected to an external negative pressure device, external air enters the dust removal chamber through the air duct of the ventilation structure and discharges the dust particles (welding slag) generated during the welding process through the negative pressure dust removal interface. This dust removal process generates a transverse flow field pointing towards the negative pressure dust removal interface in the dust removal chamber, rather than the traditional downward dominant flow field. Compared with the prior art, the dust removal mechanism for laser welding in this embodiment is more conducive to the removal and collection of dust particles during laser welding, thereby improving the dust removal effect. Attached Figure Description

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0021] Figure 1 This is a schematic diagram of the structure of the dust removal mechanism for laser welding described in an embodiment of the present invention;

[0022] Figure 2 This is a top view schematic diagram of the dust removal mechanism for laser welding described in an embodiment of this utility model;

[0023] Figure 3 for Figure 2 Schematic diagram of sectional view along direction AA;

[0024] Figure 4This is a velocity field distribution diagram from a simulated test of the dust removal mechanism for laser welding described in an embodiment of this utility model.

[0025] Figure 5 This is a spatial trace diagram of a simulated test of the dust removal mechanism for laser welding described in an embodiment of this utility model;

[0026] Figure 6 This is a dust particle sputtering trajectory diagram from a simulated test of the dust removal mechanism for laser welding described in this embodiment of the invention.

[0027] Figure 7 This is a nitrogen concentration distribution diagram from a simulated test of the dust removal mechanism for laser welding described in this embodiment of the invention.

[0028] Figure 8 This is a nitrogen concentration curve obtained from a simulated test of the dust removal mechanism for laser welding described in this embodiment of the invention.

[0029] Figure 9 This is a schematic diagram of the structure of the dust removal mechanism for laser welding described in the comparative example of this utility model;

[0030] Figure 10 This is a top view schematic diagram of the dust removal mechanism for laser welding described in the comparative example of this utility model;

[0031] Figure 11 for Figure 10 BB-direction sectional view;

[0032] Figure 12 This is a velocity field distribution diagram from a simulated test of the dust removal mechanism for laser welding described in the comparative example of this utility model.

[0033] Figure 13 This is a spatial trace diagram of a simulated test of the dust removal mechanism for laser welding described in the comparative example of this utility model;

[0034] Figure 14 This is a dust particle sputtering trajectory diagram from a simulated test of the dust removal mechanism for laser welding described in the comparative example of this utility model;

[0035] Figure 15 This is a nitrogen concentration distribution diagram from a simulated test of the dust removal mechanism for laser welding described in the comparative example of this utility model;

[0036] Figure 16 This is a nitrogen concentration curve obtained from a simulated test of the dust removal mechanism for laser welding described in the comparative example of this utility model.

[0037] In the picture:

[0038] 100. Dust collector hood; 1001. Dust collector chamber; 1002. First through hole; 200. Protective gas nozzle; 210. Nozzle interface; 220. Nozzle body; 2201. Air outlet; 221. First transition pipe; 222. Second transition pipe; 230. Porous medium; 300. Negative pressure dust collector interface; 310. Conical part; 3101. Conical cavity; 320. Interface part; 3201. Dust collector port; 400. Ventilation structure; 4001. Air duct; 500. Fixing plate; 600. Annular pressure plate; 6001. Transition surface; 700. Mounting base; 710. L-shaped base plate; 800. Rotating shaft;

[0039] 1. Laser. Detailed Implementation

[0040] To make the technical problems solved by this utility model, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of this utility model will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0041] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0042] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0043] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationships shown in the accompanying drawings. They are used solely for ease of description and simplification of operation, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," etc., are merely used for distinction in description and have no special meaning.

[0044] Example

[0045] The dust removal mechanism for laser welding in this embodiment is suitable for scenarios where dust removal is required in the welding area. The following description will take the laser welding of lithium-ion batteries as an example.

[0046] like Figures 1 to 3 As shown, the dust removal mechanism for laser welding in this embodiment of the present invention includes a dust removal hood 100, a protective gas nozzle 200, a negative pressure dust removal interface 300, and a ventilation structure 400.

[0047] The dust collector 100 has a dust collector chamber 1001. The dust collector 100 has a first side and a second side opposite to each other along a first direction (Z direction in the figure), and a third side and a fourth side opposite to each other along a second direction (X direction in the figure). The first side is provided with a first through hole 1002 communicating with the dust collector chamber 1001, and the second side is provided with a second through hole communicating with the dust collector chamber 1001. The first through hole 1002 is directly opposite the second through hole. The first through hole 1002 and the second through hole are used for the laser 1 to pass through. The first direction is perpendicular to the second direction. The protective gas nozzle 200 and the ventilation structure 400 are provided on the third side, and the negative pressure dust removal interface 300 is provided on the fourth side. The ventilation structure 400 has an air duct 4001 communicating with the outside of the dust collector chamber 1001 and the dust collector 100. The blowing port 2201 of the protective gas nozzle 200 is located inside the dust collector chamber 1001 and faces the second through hole.

[0048] Understandably, the first through hole 1002 and the second through hole opened on the first and second sides of the dust removal hood 100 are connected to the dust removal chamber 1001 to form a laser channel, that is, the laser 1 enters the dust removal chamber 1001 through the first through hole 1002 and passes through the second through hole to be projected onto the area to be welded. The protective gas nozzle 200 and ventilation structure 400 are located on the third side of the dust hood 100, while the negative pressure dust removal interface 300 is located on the fourth side opposite to the third side. During the laser welding process, the protective gas nozzle 200 blows protective gas into the area of ​​the second through hole through its blowing port 2201 to protect the welding area. When the negative pressure dust removal interface 300 is connected to an external negative pressure device, external air enters the dust removal chamber 1001 through the air duct 4001 of the ventilation structure 400, and discharges the dust particles (welding slag) generated during the welding process through the negative pressure dust removal interface 300. This dust removal process generates a transverse flow field pointing towards the negative pressure dust removal interface 300 in the dust removal chamber 1001, rather than the traditional downward flow dominant flow field. Compared with the prior art, the dust removal mechanism for laser welding in this embodiment is more conducive to the removal and collection of dust particles during the laser welding process.

[0049] Furthermore, along the first direction, the protective gas nozzle 200 is located between the ventilation structure 400 and the second side.

[0050] In this embodiment, the ventilation structure 400 is positioned above the protective gas nozzle 200, which can prevent the air entering the dust collector 100 through the air duct 4001 of the ventilation structure 400 from disturbing the protective gas blown out by the protective gas nozzle 200 and affecting the protection of the welding surface.

[0051] Furthermore, the second through hole is adjacent to the area to be welded, the protective gas nozzle 200 is inclined toward the center of the second through hole, and the air duct 4001 of the ventilation structure 400 is inclined toward the center of the second through hole.

[0052] In this embodiment, both the protective gas nozzle 200 and the air duct 4001 of the ventilation structure 400 are designed to be inclined toward the center of the second through hole. This allows the transverse flow field generated by the air entering the dust removal chamber 1001 through the air duct 4001 to be closer to the welding slag (dust particles), thereby improving the effect of the transverse flow field on carrying and removing welding slag.

[0053] like Figure 3 As shown, the negative pressure dust removal interface 300 includes a conical portion 310 and an interface portion 320. The conical portion 310 has a first end and a second end opposite to each other along a second direction. The fourth side of the dust removal hood 100 is open. The first end is connected to the fourth side of the dust removal hood 100. The conical portion 310 has a conical cavity 3101 communicating with the dust removal chamber 1001. The second end is connected to the interface portion 320. The interface portion 320 has a dust removal port 3201 communicating with the conical cavity 3101. The cross-section of the first end is larger than the cross-section of the second end.

[0054] By designing the conical portion 310 of the negative pressure dust removal interface 300 as a conical structure that narrows towards the interface portion 320, when dust particles enter the conical cavity 3101 under the action of the transverse flow field, the impact angle between the dust particles and the cavity wall of the conical cavity 3101 can be reduced, the probability of dust particles adhering to the cavity wall can be reduced, thereby improving the dust particle capture rate and reducing the number of cleaning cycles.

[0055] Alternatively, the tapered portion 310 can be a conical, polygonal, or a combination of conical and polygonal structures.

[0056] Furthermore, the interface 320 is circular with a radius of r1, the dust cover 100 is rectangular with a height of h along the first direction and a width of L along the third direction (Y direction in the figure). Then (L*h / (2*π))^0.5≤r1≤(L*h / π)^0.5, and the first direction, the second direction and the third direction are perpendicular to each other.

[0057] In this embodiment, if the radius r1 of the interface portion 320 is too small relative to the first end of the conical portion 310, the dust collection range will be limited, causing dust particles to escape and affecting the dust removal effect. Furthermore, excessive wind speed will interfere with laser welding, affecting the welding quality. If the radius r1 of the interface portion 320 is too large relative to the first end of the conical portion 310, it will cause unnecessary waste and insufficient wind speed, failing to effectively capture dust particles (especially tiny particles), and increasing the energy consumption of the negative pressure device. In this embodiment, the radius r1 of the interface portion 320 is controlled between (L*h / (2*π))^0.5 and (L*h / π)^0.5 (where L and h refer to internal dimensions), that is, the cross-sectional area π(r1) of the interface portion 320... 2 By controlling the area between L*h / 2 and L*h (where L*h is the cross-sectional area of ​​the first end of the conical part 310 (the fourth side of the dust collector hood 100)), the dust removal effect can be effectively improved.

[0058] Furthermore, the radius of the first through hole 1002 is r2, and the radius of the laser 1 at the point where the outer end face of the first through hole 1002 is tangent to the laser 1 passing through the first through hole 1002 is r3. Then r3*1.05≤r2≤r3*1.5.

[0059] In this embodiment, the first through hole 1002 is equivalent to the entrance of the laser channel. If the radius r2 of the first through hole 1002 is too large, it will cause the longitudinal airflow to be too large, thereby weakening the transverse flow field and affecting the dust removal effect. If the radius r2 of the first through hole 1002 is too small, the entrance edge will mechanically block the path of the laser 1. In this embodiment, the radius r2 of the first through hole 1002 is controlled between r3*1.05 and r3*1.5, which can achieve a balance between dust removal and welding.

[0060] For example, the ventilation structure 400 is a louver, and the louver has a plurality of spaced air ducts 4001 along the first direction. The two ends of the louver along the third direction are connected to the two side walls of the dust collection hood 100 that are opposite to each other along the third direction. The first direction, the second direction and the third direction are perpendicular to each other.

[0061] In this embodiment, the ventilation structure 400 is designed as a louver structure, which allows the air duct 4001 to extend to both ends in the third direction to the opposite side walls of the dust removal hood 100 in the third direction. This allows the outside air to form a stable transverse flow field after passing through the air duct 4001, which is set vertically and horizontally. Under the action of this stable transverse flow field, the dust particle splash trajectory is deflected in an orderly manner towards the negative pressure outlet side, which improves the dust removal efficiency and reduces the probability of dust particles overflowing or depositing inside the dust removal chamber 1001.

[0062] Furthermore, the protective gas nozzle 200 includes a nozzle interface 210, a nozzle body 220, and a porous medium 230. The nozzle body 220 is connected to the nozzle interface 210 and is inclined toward the center of the second through hole. The air outlet 2201 of the nozzle body 220 extends into the dust hood 100. The nozzle body 220 has a cavity that communicates with the nozzle interface 210 and the air outlet 2201. The porous medium 230 is installed inside the nozzle body 220.

[0063] The porous medium 230 inside the nozzle body 220 can "laminate" the outflowing protective gas, ensuring that the protective gas flowing out through the air outlet 2201 is a more stable laminar flow than turbulent flow. The flow is more stable and less prone to disturbance, thereby increasing the concentration of protective gas at the welding point.

[0064] Furthermore, the mouthpiece body 220 includes a first transition tube 221 and a second transition tube 222 connected to each other. The end of the first transition tube 221 away from the second transition tube 222 is connected to the mouthpiece interface 210. The end of the second transition tube 222 away from the first transition tube 221 is the air outlet 2201. The first transition tube 221 has a first conical chamber that gradually narrows toward the mouthpiece interface 210. The second transition tube 222 has a second conical chamber that gradually narrows toward the first transition tube 221. The porous medium 230 is installed in the second conical chamber, and the outer periphery of the porous medium 230 is attached to the cavity wall of the second conical chamber.

[0065] In this embodiment, the nozzle body 220 is designed as a "double cone" structure connected by an expansion section (first transition tube 221) and a contraction section (second transition tube 222). The porous medium 230 is installed in the second cone-shaped chamber of the contraction section, which can suppress soft retention and form a uniform gas curtain. The high-speed airflow ejected through the porous medium 230 in the contraction section can disperse the metal vapor plasma generated by laser welding, reduce the absorption or scattering of laser energy by the plasma, and improve the deep penetration welding capability.

[0066] Among them, the porosity of porous media 230 is 20%-98%.

[0067] In this embodiment, the dust removal mechanism for laser welding also includes a fixed plate 500, an annular pressure plate 600, and a mounting base 700. The second side (bottom side) of the dust removal hood 100 is attached to the fixed plate 500. The fixed plate 500 has a third through hole corresponding to the second through hole. The protective gas nozzle 200 is mounted on the fixed plate 500 through the mounting base 700. The mounting base 700 and the dust removal hood 100 are spaced apart along the second direction. The annular pressure plate 600 is arranged in a ring around the third through hole.

[0068] In this embodiment, the dust removal mechanism for laser welding allows the dust cover 100 to be stably attached to the fixed plate 500. The protective gas nozzle 200 can be mounted on the fixed plate 500 via the mounting base 700. The mounting plate and the fixed plate 500 can be fixed together by screwing, welding, or riveting. The annular pressure plate 600 is fixed to the inner wall of the third through hole. During welding, the annular pressure plate 600 is in close contact with the surface of the workpiece (e.g., a lithium battery) to prevent disorderly entry of external air; and the annular pressure plate 600 can fix the workpiece, reducing the risk of welding misalignment.

[0069] For example, the annular pressure plate 600 in this embodiment is made of a rigid material with a wetting angle greater than 90° with molten copper or aluminum, such as molybdenum, molybdenum alloy, or other materials. This type of annular pressure plate 600 does not wet with splashed copper or aluminum droplets, and welding slag (dust particles) is less likely to adhere to the pressure head, reducing cleaning frequency and saving manpower.

[0070] Furthermore, the annular pressure plate 600 has a transition surface 6001 extending to the inner wall of the annular pressure plate 600 on the first side. The transition surface 6001 is a slope or an arc surface. By setting this transition surface 6001, the annular pressure plate 600 can be prevented from blocking the protective gas from blowing towards the welding area.

[0071] Furthermore, the protective gas nozzle 200 is rotatably connected to the mounting base 700 via a rotating shaft 800. The axis of the rotating shaft 800 extends along a third direction, allowing the protective gas nozzle 200 to rotate around the rotating shaft 800. This allows the tilt angle of the protective gas nozzle 200 to be adjusted according to the actual welding conditions. Specifically, the mounting base 700 includes two L-shaped base plates 710 spaced apart along a third direction. The protective gas nozzle 200 is located between the two L-shaped base plates 710, and each side of the protective gas nozzle 200 along the third direction is rotatably connected to one L-shaped base plate 710 via a rotating shaft 800.

[0072] Next, a simulated lithium battery laser welding dust removal test was conducted on the dust removal mechanism for laser welding in this embodiment to obtain the velocity field distribution map of the inner cavity of the dust removal mechanism for laser welding. Figure 4 ), spatial trace diagram ( Figure 5 Dust particle sputtering trajectory diagram ( Figure 6 Nitrogen concentration distribution map Figure 7 ) and nitrogen concentration curve of the welding surface ( Figure 8 Take a diameter line segment from the protective gas outlet side to the negative pressure outlet side through the center of the battery welding end face, and draw a nitrogen concentration curve for this line segment.

[0073] from Figure 4 and Figure 5 As can be seen, the flow field inside the dust removal hood 100 of the laser welding dust removal mechanism in this embodiment is dominated by a transverse flow pointing towards the negative pressure port. There are no eddies inside the dust removal hood 100, which is more conducive to the removal and collection of dust and causes less disturbance to the protective gas.

[0074] from Figures 6 to 8 As can be seen, under the action of the transverse flow field, the trajectory of welding slag dust sputtering is orderly deflected towards the negative pressure dust removal outlet, which improves the dust removal efficiency and reduces the probability of dust particles overflowing or depositing inside the dust removal hood 100; the protective gas flow near the welding surface is not easily disturbed, and it is easy to reach a higher concentration at the welding point; the nitrogen concentration is about 90% at the highest point and about 85% at the lowest point.

[0075] Comparative Example

[0076] This comparative example provides a dust removal mechanism for laser welding, such as... Figures 9 to 11 As shown, the dust removal mechanism for laser welding includes a dust removal hood 100, a protective gas nozzle 200, and a negative pressure dust removal interface 300. The dust removal hood 100 has a cuboid structure, and the protective gas nozzle 200 and the negative pressure dust removal interface 300 are located on opposite sides of the dust removal hood 100.

[0077] By comparison, it can be seen that the dust removal mechanism for laser welding in this comparative example is basically the same as that in the above embodiments, the difference being that the negative pressure dust removal interface 300 in this comparative example does not have a conical part and the porous medium is removed from the protective gas nozzle 200. The dust removal mechanism for laser welding in this comparative example was subjected to a simulated lithium battery laser welding dust removal test. The velocity field distribution diagram (reference) shows... Figure 12 ) and spatial trace diagram (reference) Figure 13 As can be seen, the flow field inside the dust collector 100 is dominated by the downward flow from top to bottom at the laser channel, while there is an upward backflow on the side away from the dust collection port (the end of the negative pressure dust collection interface 300 away from the dust collector 100). There is also a vortex in front of the protective gas. The overall flow field is chaotic and disordered, which is not conducive to the removal of dust.

[0078] like Figures 14 to 16 As shown, the disordered flow field, besides being detrimental to dust extraction, also easily disturbs the protective gas, resulting in insufficient protective gas concentration in the welding area, which in turn induces oxidation defects at the welding point. In the verification structure, due to the influence of disordered flow, the protective gas—nitrogen—inside the dust collector hood 100 exhibits a characteristic of being high on one side and low on the other. Taking a diameter line segment passing through the center of the battery welding end face, pointing from the protective gas outlet side to the negative pressure outlet side, and plotting the nitrogen concentration curve for this line segment, it can be seen that the highest nitrogen concentration is about 80%, only two percentage points higher than the nitrogen content in the air (78%), indicating that the protective gas concentration is at a relatively low level. Dust particles float disorderly and erratically inside the dust collector hood 100, some of which are extracted by the negative pressure outlet with the airflow, while some fall back to the vicinity of the welding area, resulting in a low dust removal efficiency.

[0079] In addition to the above-mentioned problems, the pressure plate near the welding area is very susceptible to contamination by welding spatter in actual use. After long-term use, welding slag will adhere to its surface, requiring regular cleaning, otherwise it will easily cause product contamination.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A dust removing mechanism for laser welding characterized by comprising: include: A dust removal hood has a dust removal chamber, and has a first side and a second side opposite to each other along a first direction, as well as a third side and a fourth side opposite to each other along a second direction. The first side is provided with a first through hole communicating with the dust removal chamber, and the second side is provided with a second through hole communicating with the dust removal chamber. The first through hole is directly opposite the second through hole. The first through hole and the second through hole are used for laser to pass through, and the first direction is perpendicular to the second direction. The device includes a protective gas nozzle, a negative pressure dust removal interface, and a ventilation structure. The protective gas nozzle and the ventilation structure are located on the third side, and the negative pressure dust removal interface is located on the fourth side. The ventilation structure has an air duct connecting the dust removal chamber and the outside of the dust removal hood. The air outlet of the protective gas nozzle is located inside the dust removal chamber and faces the second through hole.

2. The dust removing mechanism for laser welding according to claim 1, characterized by Along the first direction, the protective gas nozzle is located between the ventilation structure and the second side.

3. The dust removal mechanism for laser welding according to claim 2, characterized in that, The second through hole is adjacent to the area to be welded, the protective gas nozzle is inclined toward the center of the second through hole, and the air duct of the ventilation structure is inclined toward the center of the second through hole.

4. The dust removal mechanism for laser welding according to claim 2, characterized in that, The negative pressure dust removal interface includes a conical part and an interface part. The conical part has a first end and a second end opposite to each other along the second direction. The fourth side of the dust removal hood is open. The first end is connected to the fourth side of the dust removal hood. The conical part has a conical cavity communicating with the dust removal chamber. The second end is connected to the interface part. The interface part has a dust removal port communicating with the conical cavity. The cross-section of the first end is larger than the cross-section of the second end.

5. The dust removal mechanism for laser welding according to claim 4, characterized in that, The interface is circular with a radius of r1. The dust cover is rectangular with a height of h along the first direction and a width of L along the third direction. Then (L*h / (2*π))^0.5≤r1≤(L*h / π)^0.5, and the first direction, the second direction, and the third direction are perpendicular to each other.

6. The dust removal mechanism for laser welding according to claim 4, characterized in that, The radius of the first through hole is r2, and the radius of the laser beam at the point where the outer end face of the first through hole is tangent to the laser beam passing through the first through hole is r3. Then r3*1.05≤r2≤r3*1.

5.

7. The dust removal mechanism for laser welding according to claim 2, characterized in that, The ventilation structure is a louver, and the louver has a plurality of spaced air ducts along the first direction. The two ends of the louver along the third direction are fixedly connected to the two side walls of the dust removal hood that are opposite to each other along the third direction. The first direction, the second direction and the third direction are perpendicular to each other.

8. The dust removal mechanism for laser welding according to claim 2, characterized in that, The protective gas nozzle includes a nozzle interface, a nozzle body, and a porous medium. The nozzle body is connected to the nozzle interface and is inclined toward the center of the second through hole. The air outlet of the nozzle body extends into the dust collector hood. The nozzle body has a cavity that communicates with the nozzle interface and the air outlet. The porous medium is installed in the nozzle body.

9. The dust removal mechanism for laser welding according to claim 8, characterized in that, The mouthpiece body includes a first transition tube and a second transition tube connected together. The end of the first transition tube away from the second transition tube is connected to the mouthpiece interface. The end of the second transition tube away from the first transition tube is the air inlet. The first transition tube has a first conical chamber that gradually narrows toward the mouthpiece interface. The second transition tube has a second conical chamber that gradually narrows toward the first transition tube. The porous medium is installed in the second conical chamber, and the outer periphery of the porous medium is attached to the cavity wall of the second conical chamber.

10. The dust removal mechanism for laser welding according to any one of claims 1 to 9, characterized in that, It also includes a fixing plate, an annular pressure plate and a mounting base. The second side of the dust collector is attached to the fixing plate. The fixing plate has a third through hole corresponding to the second through hole. The protective gas nozzle is mounted on the fixing plate through the mounting base. The mounting base and the dust collector are spaced apart along the second direction. The annular pressure plate is arranged around the third through hole.

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