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CN-121972807-A - Laser welding method for battery liquid cooling plate and micro-channel water nozzle

CN121972807ACN 121972807 ACN121972807 ACN 121972807ACN-121972807-A

Abstract

The invention relates to the technical field of welding, and particularly discloses a laser welding method of a battery liquid cooling plate and a micro-channel water nozzle, comprising the following steps of S1, matching the micro-channel water nozzle with a preset interface of the liquid cooling plate, forming an annular ring to be welded at the contact position of the micro-channel water nozzle and the liquid cooling plate, S2, assembling the pretreated micro-channel water nozzle to the preset interface of the battery liquid cooling plate, clamping and fixing by adopting a special positioning tool, and S3, installing a powder feeding laser stirring device; step S4, starting a powder feeding laser stirring device, feeding powder by a paraxial powder feeding pipe, enabling a laser welding head to act on an annular ring to be welded to form a molten pool, and continuously stirring the molten pool through ultrasonic vibration, step S5, after welding is completed, maintaining a fixed state of a tool, dismantling the tool after the welding line is naturally cooled to room temperature, and then carrying out surface treatment on the welding line, wherein the problem that crack risks still exist in the existing laser welding method is solved by the method for carrying out quality detection after the surface treatment of the welding line.

Inventors

  • FU LIHUA

Assignees

  • 亿升创新技术发展(深圳)有限公司

Dates

Publication Date
20260505
Application Date
20260331

Claims (10)

  1. 1. The laser welding method of the battery liquid cooling plate and the micro-channel water nozzle is characterized by comprising the following steps of: Step S1, a battery liquid cooling plate and a micro-channel water nozzle which are made of aluminum alloy materials are provided, the battery liquid cooling plate is of a micro-channel structure, the micro-channel water nozzle is matched with a preset interface of the liquid cooling plate, an annular ring to be welded is formed at the contact position of the battery liquid cooling plate and the micro-channel water nozzle, and then the surfaces of the annular ring to be welded, the micro-channel water nozzle and the liquid cooling plate are pretreated; s2, assembling the pretreated micro-channel water nozzle to a preset interface of a battery liquid cooling plate, clamping and fixing by adopting a special positioning tool, and keeping the fixed state of the tool until welding is finished; Step 3, installing a powder feeding laser stirring device, wherein the powder feeding laser stirring device comprises a paraxial powder feeding pipe, a laser welding head for generating laser beams and a vibration stirrer, the paraxial powder feeding pipe is arranged on one side of the laser welding head, the included angle between the paraxial powder feeding pipe and the laser beams is 8-10 degrees, and the distance between an outlet of the paraxial powder feeding pipe and the surface of a molten pool is 10-12 mm; Step S4, starting a powder feeding laser stirring device, feeding powder by a paraxial powder feeding pipe, enabling a laser welding head to act on an annular ring to be welded to form a molten pool, synchronously starting a vibration stirrer, enabling a vibration probe to extend into the molten pool to a depth of 2mm-3mm, and synchronously moving along the ring to be welded along with a laser beam; And S5, after welding, maintaining the fixed state of the tool, dismantling the tool after the welding line is naturally cooled to the room temperature, then carrying out surface treatment on the welding line, and carrying out quality detection after the surface treatment on the welding line.
  2. 2. The laser welding method for the battery liquid cooling plate and the micro-channel water nozzle is characterized in that in the step S1, the micro-channel water nozzle, the surface of the liquid cooling plate and the annular ring to be welded are pretreated, specifically, the micro-channel water nozzle and the surface of the liquid cooling plate are cleaned by adopting laser with the laser power of 200W-300W, the laser scanning speed is 15mm/S-20mm/S, the ring to be welded is wiped by acetone, and the ring to be welded is left to stand for 5min-8min for natural drying, so that no oxide scale exists on the surface of the ring to be welded.
  3. 3. The laser welding method for the battery liquid cooling plate and the micro-channel water nozzle according to claim 2, wherein the paraxial powder feeding pipe adopts inert gas as conveying gas, the conveying gas is high-purity argon, the gas output by the inert gas protection air nozzle is also high-purity argon, and the powder output by the inert gas is composite alloy powder.
  4. 4. The laser welding method for the battery liquid cooling plate and the micro-channel water nozzle according to claim 3, wherein the composite alloy powder comprises AlSi10 and AlSi12, the component ratio of the composite aluminum-silicon alloy powder is AlSi 10:AlSi12=7:3, and the powder granularity of the composite alloy powder is 80-120 μm.
  5. 5. The laser welding method of the battery liquid cooling plate and the micro-channel water nozzle according to any one of claims 1 or 3, wherein in the step S2, after the special positioning tool is used for clamping and fixing, the coaxiality error of the positioning tool is less than or equal to +/-0.05 mm, and the clamping force is controlled to be 50N-80N.
  6. 6. The method according to claim 5, wherein in step S4, an infrared thermometer is further included, and the infrared thermometer detects the temperature of the molten pool and controls the temperature of the molten pool to 680-720 ℃.
  7. 7. The method for laser welding of a battery liquid cooling plate and a micro-channel water nozzle according to claim 4, wherein in the step S3, a laser beam is selected from fiber laser with power of 1500W-2000W, moving speed of the laser beam is 12mm/S-18mm/S, the laser beam is perpendicular to a tangent line of a ring to be welded, angle error is less than or equal to +/-0.5 degrees, and welding stroke is the circumference of the ring to be welded.
  8. 8. The method according to claim 4, wherein in step S3, the argon gas feeding speed of the bypass powder feeding tube is equal to the moving speed of the laser beam.
  9. 9. The method for laser welding a battery liquid cooling plate and a micro-channel water nozzle according to claim 8, wherein in step S5, the weld surface is treated by polishing the weld surface with sand paper to remove slag and protrusions.
  10. 10. The laser welding method of the battery liquid cooling plate and the micro-channel water nozzle is characterized in that in the step S5, the specific steps of welding seam quality detection are that firstly, leakage detection is carried out, gas tightness detection is carried out on the welded liquid cooling plate, the gas filling pressure is 0.8MPa-1.0MPa, the pressure is maintained for 30 seconds, no bubbles and no pressure drop are qualified, then, crack detection is carried out, a penetration flaw detection method is adopted to detect welding seams, no surface cracks and internal micro cracks are qualified, finally, component detection is carried out, energy spectrum analysis is carried out on welding seam sampling, the silicon element content is determined, the silicon element content is 9% -11%, and the distribution is uniform and qualified, and the three detection needs to be met simultaneously.

Description

Laser welding method for battery liquid cooling plate and micro-channel water nozzle Technical Field The application 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. Background With the rapid development of the new energy automobile industry, the power battery is continuously upgraded to the high energy density and high power direction, the heating value in the working process of the power battery is greatly improved, and the strict requirements on the heat exchange efficiency and the reliability of a thermal management system are provided. The battery liquid cooling plate is used as a core heat exchange component of the power battery thermal management system, heat conduction is directly realized by being attached to a battery core, the connection tightness and the structural strength of the battery liquid cooling plate and a water nozzle are key for ensuring the normal operation of a cooling system, the main flow at present is a micro-channel liquid cooling plate, the width of an internal flow channel is more than 0.5-3mm, the flow channels are arranged in parallel or in series, the contact area of cooling liquid and a plate body is increased, the plate body is of a thin plate-shaped structure, the thickness is generally 5-20mm, the heat exchange efficiency and the installation space requirement are considered, the attaching degree of the battery liquid cooling plate and the battery core is high, the water nozzle is used as the only inlet and outlet channel of the cooling liquid of the liquid cooling plate, no leakage sealing is required to be realized after the water nozzle is welded with the liquid cooling plate, and otherwise the cooling liquid leakage can directly cause safety accidents such as short circuit and thermal runaway of the power battery. The microchannel water nozzle is an exclusive liquid inlet and outlet interface of the battery liquid cooling plate, the microchannel water nozzle and the liquid cooling plate are fixed into a whole at the position of a preset interface through laser welding, a to-be-welded ring is formed at the contact position of the microchannel water nozzle and the liquid cooling plate, no leakage and high strength are required to be ensured after welding, and the microchannel water nozzle is adapted to the vibration and impact working conditions of the power battery pack. The aluminum alloy has the characteristics of low thermal resistance, light weight and excellent heat conduction performance, and becomes a main stream preparation material of a battery liquid cooling plate and a water nozzle, but the welding processing of the aluminum alloy has the defects of natural materials, such as large linear expansion coefficient of the aluminum alloy, high volume shrinkage rate in the welding solidification stage, easiness in generating welding deformation and internal stress at a welding line so as to further form welding defects of shrinkage cavities, shrinkage porosity, thermal cracks and the like, and easiness in forming compact oxide skin on the surface of the aluminum alloy, wherein the oxide skin can influence the stability of a molten pool during laser welding, increase the probability of pore generation, and seriously reduce the sealing performance and mechanical performance of the welding line. The aluminum alloy battery liquid cooling plate is connected with a water nozzle in the industry at present, mainly adopts processes such as vacuum brazing, friction stir welding, CMT welding and the like, and can ensure the connection effect to a certain extent, but obvious technical short plates exist, wherein the vacuum brazing process is complex, the production efficiency is low, the welding seam strength is limited, the welding seam strength is difficult to adapt to vibration and impact working conditions of a new energy automobile, the friction stir welding is contact welding, the micro-channel structure of the liquid cooling plate is easily damaged, the heat exchange efficiency of a cooling liquid flow channel is influenced, the CMT welding heat input is large, the welding deformation of aluminum alloy parts is easily caused, and the fitting degree of the liquid cooling plate and an electric core is reduced. The laser welding is a preferred scheme for replacing the traditional welding process, and is gradually applied to the welding process of the aluminum alloy battery liquid cooling plate and the water nozzle due to the advantages of non-contact processing, high power density, large depth-width ratio of a molten pool, small thermal deformation, easiness in automatic realization and the like, but when the traditional laser welding process is directly applied to the welding of the aluminum alloy liquid cooling plate and the water nozzle, the welding pain point of an aluminum alloy material is not solved yet, the internal components of a welding line cannot