Local atmosphere adjustable large cylindrical battery seal pin laser welding device and method

Abstract

A laser welding device and method for sealing nails of large cylindrical batteries with adjustable local atmosphere belongs to the field of new energy vehicle battery welding technology. The device includes an outer shell fitted onto the top of the battery casing, a high-lens lens mounted on the top of the outer shell via a supporting frustum, an annular gas path structure disposed inside the outer shell, dividing the back of the outer shell into upper and lower chambers, a vacuum device connected to the upper chamber via a pipeline, and a dust removal device connected to the annular gas path built into the annular gas path structure via a pipeline. The annular gas path has multiple suction ports connected to the lower chamber. An elastic sealing ring is disposed in the lower chamber, and a centering ring is clamped between the elastic sealing ring and the battery casing. A sealing nail is installed on the inner ring of the centering ring. This method achieves reliable connection of sealing nails for large cylindrical batteries, improves welding quality, reduces welding defects, and solves the problem of low yield after welding sealing nails for large cylindrical batteries.

Description

Technical Field

[0001] This invention relates to a laser welding device and method for large cylindrical battery sealing nails with adjustable local atmosphere, belonging to the field of new energy vehicle battery welding technology. Background Technology

[0002] With the rapid development of large cylindrical battery technology, laser welding of sealing pins is a key process in cell packaging, and its process stability directly affects battery reliability. Its core function is to create an internal seal within the cell, preventing electrolyte penetration or intrusion of external contaminants. However, in current mass production processes, the welding of sealing pins for large cylindrical batteries still faces many unresolved problems and challenges.

[0003] This process uses a high-energy laser beam to perform circumferential welding along the sealing nail, forming a continuous and dense weld structure. However, the high welding speed during the welding process increases the volatility of the molten pool and keyhole. This instability can induce defects such as micropores and spatter, directly threatening the long-term sealing reliability of the battery cell.

[0004] To address these challenges, many studies have developed systematic process optimization strategies to improve welding quality by adjusting process parameters such as laser power and welding speed. However, there is an upper limit to the optimization of process adjustments, thus requiring methods and devices that can further improve welding quality. Summary of the Invention

[0005] The main objective of this invention is to provide a laser welding method and apparatus for sealing nails of large cylindrical batteries with adjustable local gas environment. This method provides a local vacuum environment for welding the sealing nails before welding, reducing defects such as porosity and spatter during the welding process, and improving the stability of the welding process and the consistency of the weld formation. A brief overview of the invention is provided below to offer a basic understanding of certain aspects of the invention. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention.

[0006] The technical solution of the present invention:

[0007] Option 1: A laser welding device for sealing nails of large cylindrical batteries with adjustable local atmosphere, comprising a high-lens plate, a supporting frustum, an outer shell, an annular gas path structure, an elastic sealing ring, a centering ring, sealing nails, a vacuum device, and a dust removal device. The outer shell is fitted onto the top of the battery shell. The high-lens plate is mounted on the top of the outer shell via the supporting frustum. The annular gas path structure is located inside the outer shell, dividing the back of the outer shell into upper and lower chambers. The vacuum device is connected to the upper chamber via a pipeline. The dust removal device is connected to the annular gas path built into the annular gas path structure via a pipeline. The annular gas path has multiple air intakes connected to the lower chamber. An elastic sealing ring is installed in the lower chamber. The centering ring is clamped between the elastic sealing ring and the battery shell. A sealing nail is installed on the inner ring of the centering ring.

[0008] Preferably, a vacuum valve is installed on the pipeline connecting the upper chamber to the interior, and a dust removal valve is installed on the pipeline connecting to the annular air passage built into the annular air passage structure.

[0009] Preferably, the inner diameter of the centering ring is larger than the outer diameter of the bottom of the sealing pin.

[0010] Preferably, the high-lens lens material is zinc selenide or fused silica with a surface coating treatment, the supporting frustum material is stainless steel or plexiglass, and the sealing nail material is steel.

[0011] Preferably, the high-resolution lens and the supporting frustum are sealed together by a sealing ring.

[0012] Preferably, the vacuum device has a gas flow rate range of 10~50L / s, and the dust removal device has a gas flow rate range of 8~20L / s.

[0013] Option 2: A laser welding method for large cylindrical battery sealing nails with adjustable local gas environment, based on the laser welding device for large cylindrical battery sealing nails with adjustable local atmosphere described in Option 1, characterized by the following steps:

[0014] Step 1: Before welding, wipe the surface of the sealing pin and battery casing with alcohol to remove oil and impurities. Keep the battery casing upright with the side to be welded facing upwards, and then align the sealing pin with the center of the battery casing surface to be welded.

[0015] First, the outer edge of the casing is used to center the battery casing, and then the centering ring is used to center the sealing pin. After the centering position is determined, a clamping force of 30~100N is applied to fix the relative positions of the outer edge of the casing, the centering ring, the sealing pin, and the battery casing.

[0016] Step 2: Open the vacuum valve and set the vacuum pumping speed of the vacuum device to 10~50L / s, and wait for 5 to 20 minutes until a vacuum environment is formed inside the upper and lower chambers. Then, while keeping the vacuum valve open, open the dust removal gas valve and set the dust removal gas flow rate of the dust removal device to 8~20L / s. Close the vacuum valve and wait for 1 to 2 minutes until a uniform gas flow is formed.

[0017] Step 3: Set the laser power to 450~600W, the welding speed to 12~25m / min, the defocusing amount to -1.5~+3mm, and the welding path to a circle with a diameter of 6~8mm. Add a swing mode to the laser, set the swing frequency to 800~1500Hz, and the swing amplitude to 0.5 to 1.5mm. Finally, turn on the laser and start welding. The laser beam passes through the high lens and finds the area to be welded. The heat generated will melt and form a weld.

[0018] Preferably, in step two, when the vacuum environment is formed, the vacuum valve is connected to other air intake devices, and the gas provided by the air intake devices is welding inert protective gas. After the vacuum environment is formed, the inert gas enters the upper and lower chambers through the vacuum valve to form an inert protective gas area.

[0019] The present invention has the following beneficial effects:

[0020] 1. The vacuum environment provided by this invention for welding can reduce plasma during the welding process and improve the stability of the keyhole, which helps to reduce micropores inside the weld and spatter defects during the process, thereby improving welding stability and welding quality.

[0021] 2. This invention absorbs the smoke and splashes generated during the welding process through an annular air path structure connected to a dust removal device, which can prevent smoke and splashes from falling on the high-lens lens and causing pollution, and keep the surface of the high-lens lens clean at all times, thus avoiding more energy loss when the laser energy passes through the lens.

[0022] 3. After forming a local vacuum environment, the present invention can also supply inert gas through a vacuum valve, so as to transform the local vacuum environment into a local inert gas protective environment, thereby achieving different welding effects. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a laser welding device for sealing nails of large cylindrical batteries with adjustable local atmosphere.

[0024] Figure 2 This is a 3D view of a laser welding device for sealing nails of large cylindrical batteries with adjustable local atmosphere.

[0025] Figure 3 This is a front view of a laser welding device for sealing nails of large cylindrical batteries with adjustable local atmosphere.

[0026] Figure 4 yes Figure 3 AA cross-section view;

[0027] Figure 5 yes Figure 3 BB cross-section;

[0028] Figure 6 This is a surface morphology diagram of the laser welding seam of a large cylindrical battery sealing nail under a local vacuum environment, provided in an embodiment of the present invention.

[0029] Figure 7 The surface morphology of the laser welding seam of the sealing nail of a large cylindrical battery in an inert gas environment is shown in the embodiment of the present invention.

[0030] Figure 8 The image shows the surface morphology of the laser-welded weld seam of a large cylindrical battery sealing nail under normal pressure, as provided in an embodiment of the present invention.

[0031] In the diagram, 1-high lens, 2-supporting frustum, 3-outer shell, 4-annular air passage structure, 5-elastic sealing ring, 6-centering ring, 7-sealing nail, 8-vacuum device, 9-dust removal device, 10-battery shell, 41-annular air passage, 42-intake port. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0033] The connections mentioned in this invention are divided into fixed connections and detachable connections. Fixed connections, also known as non-detachable connections, include but are not limited to conventional fixed connection methods such as folded connections, riveted connections, adhesive connections, and welded connections. Detachable connections include but are not limited to conventional disassembly methods such as threaded connections, snap-fit ​​connections, pin connections, and hinged connections. When a specific connection method is not explicitly defined, it is assumed that at least one existing connection method can always be found to achieve the function, and those skilled in the art can choose according to their needs. For example, a welded connection can be chosen for fixed connections, and a hinged connection can be chosen for detachable connections.

[0034] Specific implementation method one: Combining Figures 1-8This embodiment describes a laser welding device for sealing nails on a large cylindrical battery with adjustable local atmosphere. It includes a high-lens plate 1, a supporting frustum 2, an outer shell 3, an annular gas path structure 4, an elastic sealing ring 5, a centering ring 6, sealing nails 7, a vacuum device 8, and a dust removal device 9. The outer shell 3 is fitted onto the top of the battery shell 10. The high-lens plate 1 is mounted on the top of the outer shell 3 via the supporting frustum 2. The annular gas path structure 4 is located inside the outer shell 3, dividing the back of the outer shell 3 into upper and lower chambers. The vacuum device 8 is connected to the upper chamber via a pipe. The dust removal device 9 is connected to the annular gas path 41 built into the annular gas path structure 4 via a pipe. The annular gas path 41 has multiple suction ports 42 that communicate with the lower chamber. The lower chamber contains the elastic sealing ring 5. The centering ring 6 is clamped between the elastic sealing ring 5 and the battery shell 10. Sealing nails 7 are installed on the inner ring of the centering ring 6.

[0035] The upper chamber, vacuum device 8, and elastic sealing ring 5 together constitute a vacuum unit, used to extract air above the area to be welded and create a local vacuum environment. The annular gas path structure 4 and dust removal device 9 together constitute a dust removal unit, used to maintain the vacuum environment and absorb welding plasma and fumes. The centering ring 6 and outer shell 3 together constitute a centering unit, which respectively realizes the centering and clamping of the battery shell 10 and the sealing nail 7.

[0036] A vacuum valve is installed on the pipeline connecting the upper chamber. The vacuum device 8 can be a pump, and its main function is to create a vacuum environment inside the device. A dust removal valve is installed on the pipeline connecting to the annular gas path 41 built into the annular gas path structure 4. The dust removal device 9 can be a dust collector, which can not only absorb the plasma and metal vapor generated during welding, but also help to continuously provide a vacuum environment. In the dust removal state, welding spatter or fumes will enter the annular gas path structure 4 and flow out of the dust removal valve along the annular gas path 41. Multiple suction ports 42 connected to the lower chamber are arranged in a ring on the annular gas path 41 to ensure uniform adsorption of gas above the area to be welded and uniform gas density. The pumping gas velocity range of the vacuum device 8 is 10~50L / s, and the dust removal gas velocity range of the dust removal device 9 is 8~20L / s.

[0037] The centering ring 6 mainly serves to center the sealing nail 7 and the battery casing 10, ensuring that the sealing nail 7 is fixed in the horizontal direction inside the lower cavity. The inner diameter of the centering ring 6 is slightly larger than the diameter of the sealing nail 7 by 0.5~1.5mm. Moreover, in order to avoid metallurgical bonding between the sealing nail 7 or the battery casing 10 and the centering ring 6 during the welding process, its material is designed to be plexiglass or plastic that does not react with the welding process.

[0038] The diameter of the elastic sealing ring 5 is slightly larger than the height of the centering ring 6 by 2-3 mm. This not only ensures the airtightness of the device and maintains local vacuum conditions, but also allows it to be tightly fixed to the surface of the battery casing 10 during the welding process.

[0039] The high-lens plate 1 is made of zinc selenide or fused silica, with a laser transmittance of over 95%, reducing energy loss when the laser passes through the high-lens plate. In addition, the high-lens plate 1 should have an extremely low coefficient of thermal expansion and a surface coating treatment to reduce laser reflection loss.

[0040] The high-lens plate 1 can be designed with different diameters, ranging from 30 to 45 mm, depending on the size of the laser spot and the size of the sealing nail, to ensure that the laser is projected onto the central area of ​​the high-lens plate 1.

[0041] The supporting frustum 2 has a circular through hole in its central area, and a high lens 1 is installed thereon. The high lens 1 and the supporting frustum 2 are sealed together by a sealing ring to ensure the airtightness of the device.

[0042] The supporting frustum 2 is made of stainless steel or plexiglass. When the material is stainless steel, it can improve the stability and rigidity of the device; when the material is plexiglass, the working status of other units and the welding process can be seen through it.

[0043] The sealing nail 7 is made of steel and has a diameter of 6mm.

[0044] The outer shell 3 mainly functions to center the battery shell 10 with the center of the whole, and its inner diameter is slightly larger than the outer diameter of the battery shell 10 by 0.5~1mm; its upper part is connected to the supporting frustum 2 and together they form the overall outline of the device; the material is stainless steel or plexiglass: when the material is stainless steel, it can improve the stability and rigidity of the device; when the material is plexiglass, the working status of other units and the welding process can be seen through it.

[0045] The battery casing 10 has a diameter of 46mm and is made of steel or aluminum. The connection between the battery casing 10 and the sealing nail 7 of different materials needs to be carried out under different process parameters.

[0046] Specific Implementation Method Two: Combining Figures 1-6 This embodiment describes a laser welding method for sealing nails of large cylindrical batteries with adjustable local gas environment. It is implemented using the laser welding device for sealing nails of large cylindrical batteries with adjustable local atmosphere described in Embodiment 1, and includes the following steps: Step 1: Before welding, wipe the surface oil and impurities of the sealing nail 7 and the battery casing 10 with alcohol. Keep the battery casing 10 vertically positioned with the side to be welded facing upwards, and then attach the sealing nail 7 to the center of the surface of the battery casing 10 to be welded.

[0047] First, the outer edge shell 3 is used to center the battery casing 10, and then the centering ring 6 is used to center the sealing nail 7. After the centering position is determined, a clamping force of 30~100N is applied to fix the relative positions of the outer edge shell 3, the centering ring 6, the sealing nail 7 and the battery casing 10.

[0048] Step 2: Open the vacuum valve and set the vacuum pumping speed of vacuum device 8 to 10~50L / s, and wait for 5 to 20 minutes until a vacuum environment is formed inside the upper and lower chambers. Then, while keeping the vacuum valve open, open the dust removal gas valve and set the dust removal gas flow rate of dust removal device 9 to 8~20L / s. Close the vacuum valve and wait for 1 to 2 minutes until a uniform gas flow is formed.

[0049] Step 3: Set the laser power to 450~600W, the welding speed to 12~25m / min, the defocusing amount to -1.5~+3mm, and the welding path to a circle with a diameter of 6~8mm. Add a swing mode to the laser, set the swing frequency to 800~1500Hz, and the swing amplitude to 0.5 to 1.5mm. Finally, turn on the laser and start welding. The laser beam passes through the high lens 1 and finds the area to be welded. The heat generated will melt and form a weld.

[0050] In step two, when the vacuum environment is formed, the vacuum valve is connected to other air intake devices. The gas provided by the air intake devices is a welding inert protective gas, which can be nitrogen or argon with a purity of 99.9% or higher. After the vacuum environment is formed, the inert gas enters the upper and lower chambers through the vacuum valve to form an inert protective gas area. Different process parameters can be used to improve the welding quality.

[0051] The laser in step three can have different oscillation patterns: linear, circular, figure-eight, and infinite; different oscillation patterns can achieve different welding effects under different oscillation process parameters.

[0052] Specific implementation method three: Combining Figures 1-8 This embodiment describes a laser welding method for sealing nails on a large cylindrical battery with adjustable local gas environment, based on specific embodiment two. In this embodiment, the battery casing 10 has a diameter of 46mm; the sealing nail 7 has a diameter of 6mm; the high-lens plate 1 has a diameter of 30mm; the supporting frustum 2 and the centering ring 6 are made of plexiglass; the inner diameter of the centering ring 6 is 6.5mm; the outer shell 3 is made of stainless steel with an inner diameter of 47mm; the vacuum device 8 is a vacuum pump, and the vacuum valve is connected to the vacuum pump via a pipe; the dust removal device 9 is a dust removal system, and the dust removal valve 4 is connected to the dust collector via a pipe; the elastic sealing ring 5 has a diameter 2mm larger than the height of the centering ring 6. The specific implementation method is as follows:

[0053] Step 1: Before welding, wipe the surface of the sealing nail 7 and battery casing 10 with alcohol to remove oil and impurities. Keep the battery casing 10 vertical with the side to be welded facing upwards. Then, align the sealing nail 7 with the center of the surface of the battery casing 10 to be welded. First, use the outer edge casing 3 to center the battery casing 10, then use the centering ring 6 to center the sealing nail 7. After the centering position is determined, apply a clamping force of 30~100N to the device to fix its relative position to the workpiece.

[0054] Step 2: Open the vacuum valve and set the vacuum pumping flow rate to 30L / s, and wait 10 minutes for an internal vacuum environment to form. Then, with the vacuum valve still open, open the dust removal gas valve and set the dust removal gas flow rate to 15L / s. Close the vacuum valve and wait 1 minute for a uniform gas flow to form.

[0055] Step 3: Set the laser power to 450W, welding speed to 20m / min, defocusing distance to +1mm, and welding path to a circle with a diameter of 6mm. Add a linear oscillation mode to the laser, setting the oscillation frequency to 1200Hz and the oscillation amplitude to 0.8mm. Finally, turn on the laser and begin welding. The laser beam passes through the high lens 1 to find the area to be welded, and the heat generated will melt the workpiece to form a weld.

[0056] like Figure 6 As shown in the test, there were no defects such as blast points, pores and spatter after welding. The weld surface was smooth and clean with little deformation. The welding process did not affect other battery components. The sealing performance after welding was good.

[0057] Specific implementation method four: Combination Figures 1-5 and Figure 7-8 This embodiment describes a laser welding method for sealing nails on a large cylindrical battery with adjustable local gas environment, based on specific embodiment two. In this embodiment, the battery casing 10 has a diameter of 46mm; the sealing nail 7 has a diameter of 6mm; the high-lens plate 1 has a diameter of 40mm; the supporting frustum 2 is made of stainless steel; the centering ring 6 is made of plastic; the inner diameter of the centering ring 6 is 9mm; the outer shell 3 is made of plexiglass with an inner diameter of 46.5mm; the vacuum device 8 is a vacuum pump, and the vacuum valve is connected to the vacuum pump via a pipe; the dust removal device 9 is a dust removal system, and the dust removal valve 4 is connected to the dust collector via a pipe; the elastic sealing ring 5 has a diameter 2.5mm larger than the height of the centering ring 6. The specific implementation method is as follows:

[0058] Step 1: Before welding, wipe the surface of the sealing nail 7 and battery casing 10 with alcohol to remove oil and impurities. Keep the battery casing 10 vertical with the side to be welded facing upwards. Then, align the sealing nail 7 with the center of the surface of the battery casing 10 to be welded. First, use the outer edge casing 3 to center the battery casing 10, then use the centering ring 6 to center the sealing nail 7. After the centering position is determined, apply a clamping force of 30~100N to the device to fix its relative position to the workpiece.

[0059] Step 2: Open the vacuum valve and set the vacuum pump flow rate to 20 L / s, and wait 20 minutes for the internal vacuum environment to form. Then, close the vacuum valve and replace the pump with a gas supply device that provides 99.9% pure argon gas. Simultaneously open the vacuum valve and the dust removal gas valve and set the flow rate to 10 L / s for both, replacing the local vacuum environment with an argon protective environment.

[0060] Step 3: Set the laser power to 550W, welding speed to 15m / min, defocusing distance to -1mm, and welding path to a circle with a diameter of 8mm. Add a linear oscillation mode to the laser, setting the oscillation frequency to 800Hz and the oscillation amplitude to 0.6mm. Finally, turn on the laser and begin welding. The laser beam passes through the high lens 1 to find the area to be welded, and the heat generated will melt the workpiece to form a weld.

[0061] like Figure 7 As shown in the test, there were no defects such as blast points, pores and spatter after welding. The weld surface was smooth and clean with little deformation. The welding process did not affect other battery components. The sealing performance after welding was good.

[0062] like Figure 8 As shown in the test, the laser welding of the sealing nails of large cylindrical batteries under normal pressure showed obvious spatter and surface ablation; the quality of the sealing nail welds under local vacuum and inert gas protection environments was significantly improved, with no obvious spatter or surface porosity defects.

[0063] In summary, for sealing nails of large cylindrical batteries of various structures, a localized vacuum environment can improve welding quality, reduce welding defects, and facilitate the formation of aesthetically pleasing welds. By employing different welding parameters for workpieces of different sizes, it is possible to prevent thermal damage and short circuits in other battery structures after welding.

[0064] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be permuted and combined. Those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutation and combination. Therefore, the present invention will not describe the technical solutions after permutation and combination one by one, but it should be understood that the technical solutions after permutation and combination have been disclosed by the present invention.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A laser welding method for sealing nails of large cylindrical batteries with adjustable local gas environment, which is achieved by a laser welding device for sealing nails of large cylindrical batteries with adjustable local atmosphere, characterized in that: The device includes a high-resolution lens (1), a supporting frustum (2), an outer shell (3), an annular air passage structure (4), an elastic sealing ring (5), a centering ring (6), a vacuum device (8), and a dust removal device (9). The outer shell (3) is fitted onto the top of the battery casing (10). The high-resolution lens (1) is mounted on the top of the outer shell (3) via the supporting frustum (2). The annular air passage structure (4) is located inside the outer shell (3) and divides the back of the outer shell (3) into upper and lower layers. Each chamber has a vacuum device (8) connected to the upper chamber via a pipeline, and a dust removal device (9) connected to the annular gas path (41) built into the annular gas path structure (4) via a pipeline. The annular gas path (41) has multiple air intakes (42) connected to the lower chamber. An elastic sealing ring (5) is provided in the lower chamber. A centering ring (6) is clamped between the elastic sealing ring (5) and the battery casing (10). A sealing nail (7) is installed on the inner ring of the centering ring (6). The inner diameter of the centering ring (6) is 0.5~1.5mm larger than the outer diameter of the bottom ring of the sealing pin (7); The method includes the following steps: Step 1: Before welding, wipe the oil and impurities on the surface of the sealing nail (7) and the battery casing (10) with alcohol; keep the battery casing (10) in a vertical position with the side to be welded facing up, and then put the sealing nail (7) and the center of the surface of the battery casing (10) into contact with each other; First, use the outer edge shell (3) to center the battery shell (10), and then use the centering ring (6) to center the sealing nail (7); after the centering position is determined, apply a clamping force of 30~100N to fix the relative positions of the outer edge shell (3), the centering ring (6), the sealing nail (7) and the battery shell (10); Step 2: Open the vacuum valve and set the vacuum pumping speed of the vacuum device (8) to 10~50L / s, and wait for 5 to 20 minutes until the vacuum environment inside the upper and lower chambers is formed. Then, while keeping the vacuum valve open, open the dust removal gas valve and set the dust removal gas flow rate of the dust removal device (9) to 8~20L / s. Close the vacuum valve and wait for 1 to 2 minutes until a uniform gas flow is formed. When the vacuum environment is formed in step two, the vacuum valve is connected to other air intake devices. The gas provided by the air intake devices is welding inert protective gas. After the vacuum environment is formed, the inert gas enters the upper and lower chambers through the vacuum valve to form an inert protective gas area. Step 3: Set the laser power to 450~600W, the welding speed to 12~25m / min, the defocusing amount to -1.5~+3mm, the welding path to a circle with a diameter of 6~8mm, add a swing mode to the laser, set the swing frequency to 800~1500Hz, the swing amplitude to 0.5 to 1.5mm, and finally turn on the laser and weld. The laser beam passes through the high lens (1) to find the area to be welded, and the heat generated will melt to form a weld.

2. The laser welding method for sealing nails of large cylindrical batteries with adjustable local gas environment according to claim 1, characterized in that: A vacuum valve is installed on the pipeline connecting the upper chamber to the interior, and a dust removal valve is installed on the pipeline connecting the annular air passage (41) built into the annular air passage structure (4).

3. The laser welding method for sealing nails of large cylindrical batteries with adjustable local gas environment according to claim 1, characterized in that: The high-lens lens (1) is made of zinc selenide or fused silica and has a surface coating treatment. The supporting frustum (2) is made of stainless steel or plexiglass and the sealing nail (7) is made of steel.

4. The laser welding method for sealing nails of large cylindrical batteries with adjustable local gas environment according to claim 1, characterized in that: The high-resolution lens (1) and the supporting frustum (2) are connected by a sealing ring.

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