How are airtightness and strength ensured in the manufacturing of battery trays for new energy vehicles using aluminum-processed structural components?
Publish Time: 2026-02-27
In the "three-electric" system of new energy vehicles, the power battery pack is hailed as the "heart" of the vehicle, and the battery tray, which supports this core component, is the robust "armor" protecting the heart's safety. As aluminum-processed structural components, battery trays not only need extremely high mechanical strength to withstand collisions and road bumps, but also must possess excellent airtightness to prevent moisture and dust intrusion that could cause short circuits or thermal runaway. In the complex manufacturing chain from cutting, milling, drilling, bending to welding, ensuring these two core indicators through precision processes has become a key benchmark for measuring manufacturing quality.1. Material Foundation and Integral Forming: The Inherent Advantage of StrengthEnsuring strength begins with material selection and basic forming. New energy vehicle battery trays mostly use 6-series aluminum alloys, a material that achieves a perfect balance between strength, ductility, and corrosion resistance. In the initial processing stage, large CNC machining centers perform precision cutting and milling of aluminum alloy profiles or plates. Unlike traditional simple splicing, modern high-end trays tend to adopt a process route of "integrated die casting" or "large profile extrusion + local machining". By reducing the number of splicing seams, weak points in the structure are reduced from the source. For bending processes that must be performed, advanced roll bending or stretch bending processes combined with springback compensation algorithms ensure the continuity of metal grain flow lines at corners, avoiding cracks caused by stress concentration.2. Welding Process Innovation: The Core Defense Line for AirtightnessWelding is the most critical and challenging step in battery tray manufacturing, directly determining the upper limit of the product's airtightness. Traditional gas metal arc welding (GMAW), while efficient, has a large heat input, is prone to porosity and deformation, and cannot meet stringent sealing requirements. Therefore, friction stir welding has become the industry mainstream. It is a solid-state joining technology where the metal does not melt during welding; instead, the frictional heat generated by the high-speed rotating stirring head brings the materials to a plastic state and fuses them together. This process completely eliminates common defects such as porosity and cracks, and the weld strength can approach 90% or more of the base material strength.3. Precision Machining and Surface Treatment: Details Determine Success or FailureAfter welding, subsequent drilling, tapping, and flatness correction are equally crucial for airtightness and strength. The battery tray is densely covered with threaded holes for fixing battery cell modules, installing sensors, and connecting to the vehicle body. If the drilling position is off or the hole walls are rough, it will not only affect the assembly strength but may also become microchannels for moisture penetration. Therefore, five-axis CNC machine tools are widely used in this stage to ensure the coaxiality and perpendicularity of all mounting holes. Furthermore, to cope with long-term corrosive environments, the tray surface usually requires micro-arc oxidation or high-performance anodizing treatment.In summary, from aluminum-processed structural components to seamless connections via friction stir welding, and then to micron-level machining and surface treatment, every step revolves around the two core indicators of "airtightness" and "strength." It is these precise aluminum processing techniques that create a battery tray that is both lightweight and robust, giving new energy vehicles an unbreakable safety baseline while pursuing long driving range, thus safeguarding the future of green travel.
