Laser welding method for battery liquid cooling plate and micro-channel water nozzle

Abstract

The invention relates to the technical field of welding, and particularly discloses a laser welding method for a battery liquid cooling plate and a micro-channel water nozzle, which comprises the following steps: S1, matching the micro-channel water nozzle with a preset interface of the liquid cooling plate, and forming an annular to-be-welded ring at the contact position of the micro-channel water nozzle and the preset interface of the liquid cooling plate, S2, assembling the pretreated micro-channel water nozzle to the preset interface of the battery liquid cooling plate, a special positioning tool is adopted for clamping and fixing; S3, a powder feeding laser stirring device is installed; s4, a powder feeding laser stirring device is started, a paraxial powder feeding pipe feeds powder, a laser welding head acts on the annular to-be-welded ring to form a molten pool, and continuous stirring is conducted on the molten pool through ultrasonic vibration; s5, after welding is completed, the tool is kept in a fixed state, and the tool is dismantled after a weld joint is naturally cooled to the room temperature; and then the surface of the welding seam is treated, and quality detection is conducted after the surface of the welding seam is treated. The method solves the problem that the crack risk still exists in an existing laser welding method.

Description

Technical Field

[0001] This application relates to the field of welding technology, and specifically discloses a laser welding method for battery liquid cooling plates and microchannel water nozzles. Background Technology

[0002] With the rapid development of the new energy vehicle industry, power batteries are continuously upgrading towards higher energy density and higher power, resulting in a significant increase in heat generation during battery operation. This places stringent demands on the heat exchange efficiency and reliability of the thermal management system. As a core heat exchange component of the power battery thermal management system, the battery liquid cooling plate directly contacts the battery cell to conduct heat. Its connection to the water inlet and its structural strength are crucial for ensuring the normal operation of the cooling system. Currently, the mainstream design is a microchannel liquid cooling plate, with internal flow channel widths typically between 0.5-3mm. These channels are arranged in parallel or series to increase the contact area between the coolant and the plate. The plate itself is a thin plate structure, usually 5-20mm thick, balancing heat exchange efficiency and installation space requirements. It also has a high degree of fit with the battery cell. The water inlet, as the only channel for coolant inflow and outflow from the liquid cooling plate, must achieve a leak-free seal after welding. Otherwise, coolant leakage will directly lead to safety accidents such as short circuits and thermal runaway in the power battery.

[0003] The microchannel water nozzle is a dedicated inlet and outlet interface for the battery liquid cooling plate. It needs to be fixed to the preset interface position of the liquid cooling plate by laser welding. The contact point between the two forms a weld ring. After welding, it is necessary to ensure no leakage and high strength to adapt to the vibration and impact conditions of the power battery pack.

[0004] Due to its low thermal resistance, light weight, and excellent thermal conductivity, aluminum alloy has become the mainstream material for battery liquid cooling plates and water taps. However, its welding process has inherent material defects: aluminum alloy has a large coefficient of linear expansion and a high volume shrinkage rate during the welding solidification stage, which easily leads to welding deformation and internal stress at the weld, resulting in welding defects such as shrinkage cavities, shrinkage porosity, and hot cracks. At the same time, a dense oxide scale easily forms on the surface of aluminum alloy. During laser welding, the oxide scale will affect the stability of the molten pool, increase the probability of porosity, and seriously reduce the sealing performance and mechanical properties of the weld.

[0005] Currently, the industry mainly uses vacuum brazing, friction stir welding, and CMT welding to connect aluminum alloy battery liquid cooling plates and water nozzles. Although these processes can guarantee the connection effect to a certain extent, they have obvious technical shortcomings: vacuum brazing is a complex process with low production efficiency and limited weld strength, making it difficult to adapt to the vibration and impact conditions of new energy vehicles; friction stir welding is a contact welding process, which can easily damage the microchannel structure of the liquid cooling plate and affect the heat exchange efficiency of the coolant flow channel; CMT welding has a large heat input, which can easily lead to welding deformation of aluminum alloy components and reduce the fit between the liquid cooling plate and the battery cell.

[0006] Laser welding has become a preferred alternative to traditional welding processes due to its advantages such as non-contact processing, high power density, large weld pool depth-to-width ratio, small thermal deformation, and ease of automation. It has been gradually applied to the welding of aluminum alloy battery liquid cooling plates and water taps. However, when existing laser welding processes are directly applied to the welding of aluminum alloy liquid cooling plates and water taps, the welding pain points of the aluminum alloy material itself have not been solved: simple laser fusion welding cannot optimize the internal composition of the weld. The weld structure is prone to thermal cracking at the junction with the base material due to the single composition. In addition, during the laser welding of the annular weld ring, improper control of the laser beam angle and stroke can lead to uneven weld width. The lack or unreasonable powder feeding process can further aggravate weld defects, ultimately leading to porosity, cracks, or even leakage in the weld, which cannot meet the high reliability requirements of the power battery cooling system.

[0007] Meanwhile, in the supporting process of synchronous powder feeding in laser welding, the existing technology lacks precise design of powder feeding method, powder carrier and powder parameters: if the alloy powder feeding is unstable, it will lead to large differences in the amount of powder filling in different parts of the weld, and some areas cannot achieve composition optimization; if the powder feeding gas flow and the laser molten pool interfere with each other, it will destroy the stability of the molten pool and increase the probability of porosity; if the particle size and material of the alloy powder are not properly selected, it will lead to poor fusion bonding between the powder and the aluminum alloy base material, and it will be impossible to achieve the purpose of optimizing the weld composition and improving crack resistance.

[0008] Chinese patent application CN115476038A discloses a laser welding method for a battery liquid cooling plate and a water tap. This welding method uses a side-axis powder feeding method to solve the core problem of composition optimization, thus addressing the issue that simple laser welding cannot optimize the internal composition of the weld. However, side-axis powder feeding also introduces new problems. First, the alloy powder, after passing through the inert gas and side-axis feeding, experiences powder dispersion, leading to imbalances in the proportions or uneven weld rings because it does not pass through the molten pool. Second, relying solely on inert gas powder feeding without considering the stirring method of the molten pool can easily result in uneven mixing of the alloy powder and the molten aluminum base material, leading to insufficient silicon content in local areas of the weld and still posing a risk of cracking. Therefore, this invention provides a laser welding method for a battery liquid cooling plate and a microchannel water tap to solve the above problems. Summary of the Invention

[0009] The purpose of this invention is to solve the problem that existing laser welding methods still carry the risk of cracking.

[0010] To achieve the above objectives, the present invention provides the following basic solution:

[0011] A laser welding method for battery liquid cooling plates and microchannel water nozzles includes the following steps:

[0012] Step S1: Equip the battery liquid cooling plate and microchannel water nozzle made of aluminum alloy. The battery liquid cooling plate has a microchannel structure. The microchannel water nozzle matches the preset interface of the liquid cooling plate. A ring-shaped welding ring is formed at the contact point between the two. Then, the ring-shaped welding ring, the microchannel water nozzle, and the surface of the liquid cooling plate are pre-treated.

[0013] Step S2: Assemble the pre-treated microchannel water nozzle onto the preset interface of the battery liquid cooling plate, clamp and fix it with a special positioning fixture, and keep the fixture in a fixed state until the welding is completed.

[0014] Step S3: Install the powder feeding laser stirring device, which includes a bypass powder feeding tube, a laser welding head that generates a laser beam, and a vibrating stirrer. The bypass powder feeding tube is installed on one side of the laser welding head, with the angle between the bypass powder feeding tube and the laser beam being 8°-10°, and the distance between the outlet of the bypass powder feeding tube and the surface of the molten pool being 10mm-12mm. The vibrating stirrer is installed on the other side of the laser welding head. The vibrating stirrer includes a vibration probe and an electric telescopic device, as well as an inert gas protective nozzle that forms a local windproof protection zone for the molten pool. The inert gas protective nozzle is arranged around the laser welding head, and the protective gas flow rate is set to 3L / min-4L / min.

[0015] Step S4: Start the powder feeding laser stirring device, feed powder through the off-axis powder feeding tube, and the laser welding head acts on the annular ring to be welded to form a molten pool. The vibration stirrer starts synchronously, and the vibration probe extends into the molten pool to a depth of 2mm-3mm and moves synchronously along the ring to be welded with the laser beam; the molten pool is continuously stirred by ultrasonic vibration.

[0016] Step S5: After welding is completed, keep the fixture in a fixed state and remove the fixture after the weld has cooled to room temperature naturally; then treat the surface of the weld and perform quality inspection after the surface treatment.

[0017] Furthermore, in step S1, the microchannel water nozzle, the surface of the liquid cooling plate, and the annular ring to be soldered are pretreated as follows: the oxide scale on the surface of the microchannel water nozzle and the liquid cooling plate is cleaned with a laser with a laser power of 200W-300W and a laser scanning speed of 15mm / s-20mm / s; then the ring to be soldered is wiped with acetone and left to stand for 5min-8min to dry naturally to ensure that there is no oxide scale on the surface of the ring to be soldered.

[0018] Furthermore, the off-axis powder feeding pipe uses an inert gas as the conveying gas, which is high-purity argon. The gas output from the inert gas protection nozzle is also high-purity argon, and the powder output through the inert gas is composite alloy powder.

[0019] Furthermore, the composite alloy powder includes AlSi10 and AlSi12, and the composition ratio of the composite aluminum-silicon alloy powder is AlSi10:AlSi12=7:3. The particle size of the composite alloy powder is 80μm-120μm.

[0020] Furthermore, in step S2, after clamping and fixing with a special positioning fixture, the coaxiality error of the positioning fixture is ≤ ±0.05mm, and the clamping force is controlled between 50N and 80N.

[0021] Furthermore, in step S4, an infrared thermometer is also included, which detects the temperature of the molten pool and controls the temperature of the molten pool between 680℃ and 720℃.

[0022] Furthermore, in step S3, a fiber laser is selected as the laser beam, with a power of 1500W-2000W, a laser beam moving speed of 12mm / s-18mm / s, and the laser beam is perpendicular to the tangent of the ring to be welded, with an angle error of ≤±0.5°; the welding stroke is the circumference of the ring to be welded.

[0023] Furthermore, in step S3, the argon delivery wind speed of the off-axis powder delivery tube is equal to the moving speed of the laser beam.

[0024] Furthermore, in step S5, the specific surface treatment of the weld is as follows: the weld surface is polished with sandpaper to remove weld slag and protrusions.

[0025] Furthermore, in step S5, the specific steps for weld quality inspection are as follows: First, leakage detection is performed: the air tightness of the welded liquid cooling plate is tested, with an inflation pressure of 0.8MPa-1.0MPa and a pressure holding time of 30s. No bubbles or pressure drop indicates acceptance. Then, crack detection is performed: the weld is inspected using penetrant testing. No surface cracks or internal micro-cracks indicate acceptance. Finally, compositional analysis is performed: samples of the weld are analyzed using energy dispersive spectroscopy to determine the silicon content. A silicon content of 9%-11% with uniform distribution indicates acceptance. All three tests must be met simultaneously.

[0026] The principle and effect of this solution are as follows:

[0027] 1. Compared with the prior art, the present invention solves the problem of powder dispersion in off-axis powder feeding: by accurately calibrating the powder feeding wind speed and the installation position of the powder feeding pipe, and with the local wind protection of the molten pool, the directional and quantitative feeding of powder is realized, the powder utilization rate is greatly improved, the production loss is reduced, and at the same time, the powder filling amount in the molten pool is uniform, and the weld composition optimization effect is stable.

[0028] 2. Compared with the prior art, the present invention solves the problem of uneven mixing of the molten pool: by actively stirring the molten pool with ultrasonic vibration, the alloy powder and the molten aluminum alloy base material are fully mixed, eliminating component segregation, improving the uniformity of the internal composition of the weld, and reducing the probability of welding defects such as hot cracks and porosity from the root.

[0029] 3. Compared with the prior art, the core parameters of the present invention are disclosed and precisely calibrated: the alloy powder composition, the molten pool temperature range, and the powder feeding wind speed are clearly defined, which makes the process highly reproducible and adaptable to mass production. There is no need for repeated debugging, which reduces the cost of trial and error and ensures the consistency of welding quality of different batches of products. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 The diagram shows a schematic flow chart of a laser welding method for a battery liquid cooling plate and a microchannel water nozzle according to an embodiment of this application. Detailed Implementation

[0032] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0033] A laser welding method for battery liquid cooling plates and microchannel water nozzles, such as... Figure 1 As shown:

[0034] Includes the following steps:

[0035] Step S1: Equip the battery liquid cooling plate and microchannel water nozzle made of aluminum alloy. The battery liquid cooling plate has a microchannel structure. The microchannel water nozzle matches the preset interface of the liquid cooling plate. A ring-shaped welding ring is formed at the contact point between the two. Then, the ring-shaped welding ring, the microchannel water nozzle, and the surface of the liquid cooling plate are pre-treated.

[0036] The microchannel water nozzle, liquid cooling plate surface, and annular ring to be soldered are pretreated as follows: use a laser with a power of 200W-300W to clean the oxide scale on the surface of the microchannel water nozzle and liquid cooling plate, with a laser scanning speed of 15mm / s-20mm / s; then wipe the ring to be soldered with acetone and let it stand for 5min-8min to dry naturally to ensure that there is no oxide scale on the surface of the ring to be soldered.

[0037] Step S2: Assemble the pre-treated microchannel water nozzle onto the preset interface of the battery liquid cooling plate, clamp and fix it with a special positioning fixture, and keep the fixture in a fixed state until the welding is completed.

[0038] Regarding tooling: Since each OEM has different battery models and microchannel designs, the corresponding tooling is different. Therefore, this application will not disclose the tooling corresponding to this liquid cooling plate. After clamping and fixing with a special positioning tooling, the coaxiality error of the positioning tooling is ≤ ±0.05mm, and the clamping force is controlled between 50N and 80N.

[0039] Step S3: Install the powder feeding laser stirring device, which includes a bypass powder feeding tube, a laser welding head that generates a laser beam, and a vibrating stirrer. The bypass powder feeding tube is installed on one side of the laser welding head, with the angle between the bypass powder feeding tube and the laser beam being 8°-10°, and the distance between the outlet of the bypass powder feeding tube and the surface of the molten pool being 10mm-12mm. The vibrating stirrer is installed on the other side of the laser welding head. The vibrating stirrer includes a vibration probe and an electric telescopic device, as well as an inert gas protective nozzle that forms a local windproof protection zone for the molten pool. The inert gas protective nozzle is arranged around the laser welding head, and the protective gas flow rate is set to 3L / min-4L / min.

[0040] Specifically: In step S3, a fiber laser is selected as the laser beam, with a power of 1500W-2000W and a laser beam moving speed of 12mm / s-18mm / s. The laser beam is perpendicular to the tangent of the ring to be welded, with an angle error of ≤±0.5°. The welding stroke is the circumference of the ring to be welded. In step S3, the argon gas delivery wind speed of the off-axis powder feeding pipe is equal to the moving speed of the laser beam.

[0041] Specifically: the off-axis powder feeding pipe uses inert gas as the conveying gas, the conveying gas is high-purity argon, the gas output from the inert gas protection nozzle is also high-purity argon, and the powder output through the inert gas is composite alloy powder.

[0042] Regarding composite alloy powders:

[0043] The composite alloy powder includes AlSi10 and AlSi12, and the composition ratio of the composite aluminum-silicon alloy powder is AlSi10:AlSi12=7:3. The particle size of the composite alloy powder is 80μm-120μm.

[0044] Step S4: Start the powder feeding laser stirring device. The off-axis powder feeding tube feeds powder. The laser welding head acts on the annular ring to be welded to form a molten pool. The vibration stirrer starts synchronously. The vibration probe extends into the molten pool to a depth of 2mm-3mm and moves synchronously along the ring to be welded with the laser beam. The molten pool is continuously stirred by ultrasonic vibration. At the same time, an infrared thermometer is also included. The infrared thermometer detects the temperature of the molten pool and controls the temperature of the molten pool at 680℃-720℃.

[0045] The integration of steps S3 and S4 is as follows: The laser welding machine is started, the laser welding head generates a laser beam, and the laser beam begins welding the annular ring to be welded according to the calibrated parameters, forming a molten pool around the ring. After laser welding starts, the off-axis powder feeding pipe is activated, and the dried alloy powder is directionally blown into the molten pool according to the calibrated powder feeding air velocity, ensuring uniform powder filling within the molten pool. The powder feeding process is synchronized with the entire laser welding process; that is, the movement of the laser welding head drives the movement of the off-axis powder feeding pipe, which is accompanied by the movement of the vibrating stirrer. During the movement... This process will cause the molten pool to form. The vibratory stirrer is then activated. The vibratory stirrer uses ultrasonic vibration stirring at a frequency of 20kHz-25kHz. The vibratory probe is inserted into the molten pool to a depth of 2mm-3mm using an electric telescopic rod and moves synchronously along the welding ring with the laser beam. The ultrasonic vibration continuously stirs the molten pool, breaking up the component stratification within the molten pool and ensuring that the molten aluminum-silicon alloy powder and the molten aluminum alloy base material are fully mixed, eliminating component segregation. The stirring process is stopped before the molten pool is completely solidified to avoid stress damage to the solidified weld.

[0046] The temperature of the molten pool is monitored in real time by an infrared thermometer. If the temperature exceeds the range of 680℃-720℃, the laser welding power is adjusted in real time for temperature control: when the temperature is higher than 720℃, the laser power is reduced by 100W-200W; when the temperature is lower than 680℃, the laser power is increased by 100W-200W to ensure that the temperature of the molten pool is always within the calibrated range.

[0047] Step S5: After welding is completed, keep the fixture in a fixed state and remove the fixture after the weld has cooled to room temperature naturally; then treat the surface of the weld and perform quality inspection after the surface treatment.

[0048] Specifically: In step S5, the surface treatment of the weld is as follows: the weld surface is polished with sandpaper to remove weld slag and protrusions. The specific steps for weld quality inspection are as follows: First, leakage detection is performed: the air tightness of the welded liquid cooling plate is tested, with an inflation pressure of 0.8MPa-1.0MPa and a pressure holding time of 30s. No bubbles or pressure drop indicates acceptance. Then, crack detection is performed: the weld is tested using penetrant testing. No surface cracks or internal micro-cracks indicate acceptance. Finally, compositional analysis is performed: samples of the weld are analyzed by energy dispersive spectroscopy to determine the silicon content. A silicon content of 9%-11% with uniform distribution indicates acceptance. All three tests must be met simultaneously.

[0049] Example 1:

[0050] This embodiment focuses on the laser welding of a φ15mm annular weld ring, a 6061 aluminum alloy battery liquid cooling plate, and a microchannel water nozzle. The specific steps are as follows:

[0051] After cleaning the ring to be welded, the alloy powder of AlSi10 and AlSi12 in a 7:3 ratio was dried at 130℃ for 2.5h, with argon purity of 99.99%. Tooling positioning: the coaxiality error of the positioning tooling was ±0.03mm, the clamping force was 60N, ensuring no gap between the water nozzle and the liquid cooling plate; laser power was 1800W, the moving speed was 12mm / s, and the welding stroke was φ15mm; the molten pool temperature was controlled at 680℃-720℃, the powder feeding air velocity was 12mm / s, and the angle between the powder feeding tube and the laser beam was 8°. The outlet distance from the molten pool is 10mm; the ultrasonic vibration frequency is 22kHz, and the vibration probe extends 2.5mm into the molten pool; the shielding gas flow rate is set to 3L / min-4L / min; after the powder feeding and ultrasonic stirring are completed simultaneously, the molten pool temperature is monitored in real time by an infrared thermometer, and the laser power is dynamically adjusted with the temperature; after welding is completed, the weld is ground after cooling to room temperature, the air tightness test is performed with a pressure holding of 0.9MPa for 30s without leakage, the penetrant testing shows no cracks, and the energy dispersive spectroscopy analysis shows that the silicon content is 10% and evenly distributed, indicating that the welding is qualified.

[0052] Example 2: This example focuses on the laser welding of a φ20mm annular ring to be welded, a 3003 aluminum alloy battery liquid cooling plate, and a microchannel water nozzle. The specific steps are as follows: Preparation before welding: After cleaning the ring to be welded, the alloy powder, a 7:3 mixture of AlSi10 and AlSi12, is dried at 140℃ for 2 hours, with argon gas purity of 99.99%. The coaxiality error of the positioning fixture is ±0.04mm, and the clamping force is 70N, ensuring no gap between the water nozzle and the liquid cooling plate. Parameter calibration: Laser power 2000W, moving speed 18mm / s, welding stroke φ20mm. mm; molten pool temperature controlled at 680℃-720℃, powder feeding air velocity 18mm / s; powder feeding pipe angled at 10° to laser beam, outlet distance 12mm from molten pool; ultrasonic vibration frequency 24kHz, vibration probe inserted 3mm into molten pool; shielding gas flow rate set to 3L / min-4L / min; simultaneous powder feeding and ultrasonic stirring, real-time temperature control of molten pool; after welding, cool to room temperature and grind weld seam; air tightness test at 1.0MPa pressure for 30s with no leakage, penetrant testing with no cracks, energy dispersive spectroscopy analysis showing silicon content of 9.5% with uniform distribution, welding qualified.

[0053] This method solves the problem that existing laser welding methods still carry the risk of cracking.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A laser welding method for a battery liquid cooling plate and a microchannel water nozzle, characterized in that, Includes the following steps: Step S1: Equip the battery liquid cooling plate and microchannel water nozzle made of aluminum alloy. The battery liquid cooling plate has a microchannel structure. The microchannel water nozzle matches the preset interface of the liquid cooling plate. A ring-shaped welding ring is formed at the contact point between the two. Then, the ring-shaped welding ring, the microchannel water nozzle, and the surface of the liquid cooling plate are pre-treated. Step S2: Assemble the pre-treated microchannel water nozzle onto the preset interface of the battery liquid cooling plate, clamp and fix it with a special positioning fixture, and keep the fixture in a fixed state until the welding is completed. Step S3: Install the powder feeding laser stirring device, which includes a bypass powder feeding tube, a laser welding head that generates a laser beam, and a vibrating stirrer. The bypass powder feeding tube is installed on one side of the laser welding head, with the angle between the bypass powder feeding tube and the laser beam being 8°-10°, and the distance between the outlet of the bypass powder feeding tube and the surface of the molten pool being 10mm-12mm. The vibrating stirrer is installed on the other side of the laser welding head. The vibrating stirrer includes a vibration probe and an electric telescopic device, as well as an inert gas protective nozzle that forms a local windproof protection zone for the molten pool. The inert gas protective nozzle is arranged around the laser welding head, and the protective gas flow rate is set to 3L / min-4L / min. Step S4: Start the powder feeding laser stirring device, feed powder through the off-axis powder feeding tube, and the laser welding head acts on the annular ring to be welded to form a molten pool. The vibration stirrer starts synchronously, and the vibration probe extends into the molten pool to a depth of 2mm-3mm and moves synchronously along the ring to be welded with the laser beam; the molten pool is continuously stirred by ultrasonic vibration. Step S5: After welding is completed, keep the fixture in a fixed state and remove the fixture after the weld has cooled to room temperature naturally; then treat the surface of the weld and perform quality inspection after the surface treatment.

2. The laser welding method for a battery liquid cooling plate and a microchannel water nozzle according to claim 1, characterized in that, In step S1, the microchannel water nozzle, the surface of the liquid cooling plate, and the annular ring to be soldered are pretreated as follows: the oxide scale on the surface of the microchannel water nozzle and the liquid cooling plate is cleaned with a laser with a laser power of 200W-300W and a laser scanning speed of 15mm / s-20mm / s; then the ring to be soldered is wiped with acetone and left to stand for 5min-8min to dry naturally to ensure that there is no oxide scale on the surface of the ring to be soldered.

3. The laser welding method for a battery liquid cooling plate and a microchannel water nozzle according to claim 2, characterized in that, The off-axis powder feeding pipe uses inert gas as the conveying gas, which is high-purity argon. The gas output from the inert gas protection nozzle is also high-purity argon. The powder output through the inert gas is composite alloy powder.

4. The laser welding method for a battery liquid cooling plate and a microchannel water nozzle according to claim 3, characterized in that, The composite alloy powder includes AlSi10 and AlSi12, and the composition ratio of the composite aluminum-silicon alloy powder is AlSi10:AlSi12=7:

3. The particle size of the composite alloy powder is 80μm-120μm.

5. A laser welding method for a battery liquid cooling plate and a microchannel water nozzle according to any one of claims 1 or 3, characterized in that, In step S2, after clamping and fixing with a special positioning fixture, the coaxiality error of the positioning fixture is ≤ ±0.05mm, and the clamping force is controlled between 50N and 80N.

6. The laser welding method for a battery liquid cooling plate and a microchannel water nozzle according to claim 5, characterized in that, In step S4, an infrared thermometer is also included, which detects the temperature of the molten pool and controls the temperature of the molten pool between 680℃ and 720℃.

7. The laser welding method for a battery liquid cooling plate and a microchannel water nozzle according to claim 4, characterized in that, In step S3, a fiber laser is selected as the laser beam, with a power of 1500W-2000W and a laser beam moving speed of 12mm / s-18mm / s. The laser beam is perpendicular to the tangent of the ring to be welded, with an angle error of ≤±0.5°. The welding stroke is the circumference of the ring to be welded.

8. The laser welding method for a battery liquid cooling plate and a microchannel water nozzle according to claim 4, characterized in that, In step S3, the argon delivery wind speed of the off-axis powder feeding tube is equal to the moving speed of the laser beam.

9. The laser welding method for a battery liquid cooling plate and a microchannel water nozzle according to claim 8, characterized in that, In step S5, the specific surface treatment of the weld is as follows: the weld surface is polished with sandpaper to remove weld slag and protrusions.

10. The laser welding method for a battery liquid cooling plate and a microchannel water nozzle according to claim 9, characterized in that, In step S5, the specific steps for weld quality inspection are as follows: First, leakage detection is performed: the air tightness of the welded liquid cooling plate is tested, with an inflation pressure of 0.8MPa-1.0MPa and a pressure holding time of 30s. No bubbles or pressure drop indicates compliance. Then, crack detection is performed: the weld is inspected using penetrant testing. No surface cracks or internal micro-cracks indicate compliance. Finally, compositional analysis is performed: samples of the weld are analyzed using energy dispersive spectroscopy to determine the silicon content. A silicon content of 9%-11% with uniform distribution indicates compliance. All three tests must be met simultaneously.

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