Laser welding device with shielding gas heating function

Abstract

The utility model discloses a laser welding device with a shielding gas heating function, which comprises a laser welding module, a shielding gas heating module is arranged on one side of the laser welding module, the shielding gas heating module comprises a cavity, the cavity is provided with a gas inlet and a gas outlet, a heating rod is arranged in the cavity, and the shielding gas heating module is arranged in the cavity. The air outlet is connected with an air supply pipe, and an outlet of the air supply pipe is arranged below a laser vibration mirror of the laser welding module. According to the utility model, nitrogen reaching a working procedure can be heated in advance, so that the consistency of the temperature of protective gas is ensured; and meanwhile, the shielding gas heating device has a temperature adjustable and controllable function, and the optimal temperature of the shielding gas can be confirmed by discussing the influence of the shielding gas at different temperatures on gas holes and cracks after welding, so that the cooling speed after welding is slowed down, the gas escapes from a molten pool, the probability of generating the welding cracks and the gas holes is reduced, and the welding quality is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of battery welding devices, in particular to a laser welding device with a protective gas heating function. Background Art

[0002] In the assembly of battery cells, laser welding is required in many processes. During the laser welding process, the high-energy heat source of the laser will melt the material quickly. The metal in the molten state is very active and easily undergoes an oxidation reaction with the oxygen in the atmosphere. It is very violent. Intuitively, there are a lot of spatters, pores, and welding slag everywhere. Therefore, shielding gas is often required during laser welding. One function of shielding gas is to isolate the molten pool from oxygen. The shielding gas sprays around the molten pool to form a flowing inert gas environment, and the molten metal and oxygen are in direct contact. Another function of laser welding shielding gas is to blow away the plasma.

[0003] At present, nitrogen is the commonly used shielding gas for laser welding. During laser welding, nitrogen invades the molten pool from the outside. The solubility of nitrogen in liquid iron is very different from that in solid iron. Therefore, during the cooling and solidification of the metal, since the solubility of nitrogen decreases with the decrease in temperature, when the molten pool metal cools to the point where crystallization begins, the solubility will suddenly drop sharply. At this time, a large amount of gas will precipitate to form bubbles. If the floating speed of the bubbles is less than the crystallization speed of the metal, pores will be generated. At the same time, if the temperature drops too quickly after welding, the surface stress of the material changes, and cracks will occur. Therefore, the shielding gas temperature must be kept at the required temperature during welding. However, in existing laser welding, due to the large consumption of nitrogen, most companies will establish nitrogen storage stations and then connect the corresponding processes through pipelines, but they are easily affected by the external temperature. There are differences in the nitrogen temperature reaching the process. Due to the lack of effective management of the nitrogen temperature, the welding quality is unstable. Utility Model Content

[0004] The utility model aims to overcome the shortcomings and defects of the existing laser welding technology under protective gas and provide a laser welding device with a protective gas heating function.

[0005] A laser welding device with a shielding gas heating function comprises a laser welding module, one side of the laser welding module is provided with a shielding gas heating module, the shielding gas heating module comprises a cavity, the cavity has an air inlet and an air outlet, a heating rod is provided inside the cavity, the air outlet is connected to an air supply pipe, and the outlet of the air supply pipe is arranged below the laser vibration mirror of the laser welding module.

[0006] Wherein, the air inlet and the air outlet are respectively connected to a valve for controlling the amount of air inlet and outlet.

[0007] Wherein, a temperature probe is installed on the cavity.

[0008] Wherein, the laser welding module includes a base for positioning the battery to be welded, and the base is located below the laser vibration mirror.

[0009] Wherein, a positioning groove for positioning the battery is formed on the upper surface of the base.

[0010] Wherein, a dust removal nozzle is arranged above one side of the base, and the dust removal nozzle is connected to the dust removal pipe.

[0011] Wherein, the dust removal nozzle is arc-shaped or U-shaped.

[0012] Wherein, a welding bracket is arranged on one side of the base, and a battery cell pressing device is provided on the welding bracket.

[0013] Wherein, the battery core pressing device includes a vertically arranged rotating cylinder and a pressing ring installed on the top end of the rotating cylinder.

[0014] The outlet of the air supply pipe is arranged to be tilted downward, pointing to the upper end of the battery to be welded.

[0015] The utility model discloses a laser welding device with a shielding gas heating function, which can heat the nitrogen arriving at the process in advance to ensure the consistency of the shielding gas temperature; at the same time, the shielding gas heating device has a temperature controllable function, which can detect the influence of shielding gas on welding pores and cracks at different temperatures, thereby confirming the optimal temperature of the shielding gas, thereby slowing down the cooling speed after welding, escaping the gas from the molten pool, reducing the probability of welding cracks and pores, and improving the welding quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the laser welding device with protective gas heating function of the utility model.

[0017] Figure 2 It is a schematic diagram of the local structure of the laser welding module of the present utility model.

[0018] Figure 3 It is a structural diagram of the protective gas heating module of the utility model.

[0019] Figure 4 This is a metallographic image of the welding point after the battery is welded without nitrogen heating.

[0020] Figure 5 This is a metallographic image of the cracks at the weld after the battery was welded without nitrogen heating.

[0021] Figure 6 This is the metallographic image of the weld after the battery is welded under nitrogen heating.

[0022] Figure 7 This is a metallographic image of cracks at the weld after the battery is welded under nitrogen heating. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] like Figures 1 to 3 As shown, the embodiment of the utility model provides a laser welding device with a protective gas heating function, including a laser welding module, and a protective gas heating module is provided on one side of the laser welding module. Figure 3 As shown, the protective gas heating module includes a cavity 1, the cavity has an air inlet 3 and an air outlet 4, a heating rod 2 is provided inside the cavity, the air outlet 4 is connected to an air supply pipe 7, and the outlet of the air supply pipe 7 is arranged below the laser vibration mirror 8 of the laser welding module.

[0025] In this application, the laser welding module adopts the lower laser welding equipment of the prior art to weld the battery by laser. The air inlet is located at the lower end of one side of the cavity, and the air outlet is located at the upper end of the other side of the cavity. The air outlet is connected to the welding point by an air supply pipe. The nitrogen blowing angle is adjustable at 30-90°, the nitrogen flow rate is 20-50L / min, and the heating rod temperature adjustment range is 30-80°C. Among them, the outlet of the air supply pipe is arranged to tilt downward, pointing to the upper end of the battery to be welded, so as to better achieve welding.

[0026] In the present application, the nitrogen is heated to ensure the consistency of the nitrogen temperature, thereby avoiding the adverse effects of the nitrogen temperature during the welding process, such as cracks and pores.

[0027] In a preferred embodiment, see Figure 3 As shown, the air inlet and the air outlet are each connected to a valve 6 for controlling the amount of air inlet and outlet, and are used to control the amount of nitrogen inlet and outlet.

[0028] See also Figure 3 As shown, in one embodiment, a temperature probe 5 is installed on the cavity to monitor the nitrogen temperature at the outlet. The outlet gas temperature is ±3°C of the heating rod temperature. The nitrogen temperature at the outlet is monitored by the temperature probe, and the power of the heating rod is controlled by the temperature control system to achieve automatic control of the heating temperature of the nitrogen.

[0029] Among them, the laser welding module includes a base 14 for positioning the battery 100 to be welded, and the base is located below the laser vibration mirror 8. The base can be used to effectively position the battery to be welded to prevent the battery from shifting during the welding process and affecting the welding. The air supply pipe can be fixed or fixed together with the side of the base through a connecting rod.

[0030] Furthermore, a positioning groove 13 for positioning the battery is formed on the upper surface of the base. The battery is positioned through the positioning groove, and the positioning groove adapts to the shape of the battery. For example, when welding a cylindrical battery, it is a round hole groove, and when welding a square battery, it can be a square groove, etc., and is designed according to the shape of the battery.

[0031] In a preferred embodiment, a dust removal nozzle 10 is arranged above one side of the base 14, and the dust removal nozzle is connected to a dust removal pipe. Preferably, the dust removal pipe is located 2-3 cm from the welding part side, and the dust removal wind speed is 15-40 m / s, which can completely remove dust from the welding surface. More preferably, the dust removal nozzle is arc-shaped or U-shaped.

[0032] Among them, a welding bracket 9 is arranged on one side of the base, and a battery cell clamping device is arranged on the side of the welding bracket, which is used to clamp the battery during the welding process of the battery to prevent movement from affecting the welding. In a preferred embodiment, the battery cell clamping device includes a vertically arranged rotating cylinder 12 and a clamping ring 11 installed on the top of the rotating cylinder. The clamping ring is driven by the rotating cylinder to rotate and rise and fall, so that the battery is clamped in the positioning groove before welding.

[0033] The rotary cylinder 12 is arranged on the side of the welding bracket, located between the welding bracket and the base, and is connected to the clamping ring 11 through a connecting piece 15 to drive the lifting action of the clamping ring.

[0034] It can be seen that the laser welding device with a shielding gas heating function of the utility model can heat the nitrogen arriving at the process in advance. By heating the nitrogen before welding to the required temperature or a temperature that meets the requirements, the consistency of the shielding gas temperature can be ensured, thereby reducing the influence of the nitrogen temperature on the welding quality. Figure 4 , Figure 5 They are the metallographic images of the welding point and crack after the battery was welded without nitrogen heating. Figure 6 , Figure 7 The metallographic images of the welding point and crack after the battery was welded under nitrogen heating are shown in Figure 2. Figure 4 , Figure 5 as well as Figure 6 , Figure 7It can be seen that the welding appearance and crack metallographic diagram of the battery after welding under nitrogen heating are more in line with the quality requirements of battery welding, with relatively few welding cracks and pores and good welding quality.

[0035] The laser welding device of the present application has a temperature control function. It can verify the welding quality at different temperatures by reviewing / exploring the influence of shielding gas at different temperatures on the pores and cracks after welding, formulate the optimal nitrogen temperature, improve the welding consistency, and reduce the losses caused by poor welding. At the same time, by confirming the optimal temperature of the shielding gas, the cooling speed after welding can be slowed down, the gas can escape from the molten pool, the probability of welding cracks and pores can be reduced, and the welding quality can be improved.

[0036] When in use, place the battery cell on the lower base, and fix the battery cell with a clamping ring through the pressure of the rotating cylinder so that the gap between the positive collector plate and the positive column of the battery is less than 0.1mm. Then turn on the power of the nitrogen heating module, set the temperature of the heating rod to 30℃ for heating, open the air inlet valve to allow nitrogen to enter the cavity for heating, confirm the temperature of the air outlet and the heating rod, connect the air outlet to the blowing nozzle with an air pipe, and the blowing angle is 30°. Then turn on the laser power, confirm the welding parameters, turn on the dust removal at the same time, and adjust the dust removal wind speed to 20m / s.

[0037] Start the welding procedure and perform welding. After welding, use a microscope to observe the welding surface state to see if there are cracks, explosion spots, etc. Perform metallographic analysis on the welding cells with poor appearance to confirm whether there are cracks inside, and measure the penetration depth and penetration width. At this temperature, the defect rate of cracks, pores, and explosion spots after small batch welding is 1.01%. Set the nitrogen temperature to 40℃, 50℃, and 60℃, and the statistical defect rates of welding the same number of cells are 0.68%, 0.32%, and 0.33%, respectively. After turning off the nitrogen heating, the defect rate of welding is 1.27%.

[0038] As mentioned above, by comparing the defective rates of welding at different temperatures, when the nitrogen temperature is 50°C, the incidence of defects such as cracks and pores is the lowest.

[0039] The above shows and describes the basic principle and main features of the utility model and the advantages of the utility model. For those skilled in the art, it is obvious that the utility model is not limited to the details of the above exemplary embodiments, and the utility model can be implemented in other specific forms without departing from the spirit or basic features of the utility model.

[0040] Therefore, no matter from which point of view, the embodiments should be regarded as illustrative and non-restrictive, and the scope of the present invention is limited by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

[0041] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A laser welding device with a protective gas heating function, comprising a laser welding module, characterized in that: A shielding gas heating module is provided on one side of the laser welding module. The shielding gas heating module includes a cavity having an air inlet and an air outlet. A heating rod is provided inside the cavity. The air outlet is connected to an air supply pipe. The outlet of the air supply pipe is arranged below the laser vibration mirror of the laser welding module.

2. The laser welding device with protective gas heating function according to claim 1, characterized in that: The air inlet and the air outlet are each connected to a valve for controlling the amount of air inlet and outlet.

3. The laser welding device with protective gas heating function according to claim 1, characterized in that: A temperature probe is installed on the cavity.

4. The laser welding device with protective gas heating function according to claim 1, characterized in that: The laser welding module comprises a base for positioning the battery to be welded, and the base is located below the laser vibration mirror.

5. The laser welding device with protective gas heating function according to claim 4, characterized in that: A positioning groove for positioning the battery is formed on the upper surface of the base.

6. The laser welding device with protective gas heating function according to claim 4, characterized in that: A dust removal nozzle is arranged above one side of the base, and the dust removal nozzle is connected to the dust removal pipe.

7. The laser welding device with protective gas heating function according to claim 6, characterized in that: The dust removal nozzle is arc-shaped or U-shaped.

8. The laser welding device with a protective gas heating function according to claim 4, characterized in that: A welding bracket is arranged on one side of the base, and a battery core pressing device is provided on the welding bracket.

9. The laser welding device with a protective gas heating function according to claim 8, characterized in that: The battery core pressing device comprises a vertically arranged rotating cylinder and a pressing ring installed on the top end of the rotating cylinder.

10. The laser welding device with a protective gas heating function according to claim 7, characterized in that: The outlet of the air supply pipe is arranged to be tilted downward, pointing to the upper end of the battery to be welded.

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