Low-Pressure Die Casting of Aluminium Alloy Components for Electric Vehicle Battery Enclosures

Abstract

The production of battery boxes for electric vehicles typically relies on extrusions joined by welding, riveting, or adhesives, with minimal use of casting components due to their lower performance and higher defect rates. This study aims to enhance the structure and properties of battery box corner nodes, making them more reliable and viable for broader use in electric vehicle manufacturing. We employed Low-pressure Die Casting to produce the corner nodes, replacing previous sand-casting method known for higher porosity. A new die design, developed in collaboration with our industrial partner, allows for the simultaneous casting of four corner nodes, reducing die filling turbulence and improving casting integrity. Additionally, we used electric heating for the die and furnace to lower CO<jats:sub>2</jats:sub> emissions compared to traditional gas burning heating methods. Advanced characterization techniques, including X-ray tomography and Profilometry-based indentation plastometry (PIP), were used to evaluate the internal structure and properties of the castings. Our findings indicate excellent mould filling with minimal porosity defects and good mechanical properties, though with some variability. This variability correlates with the presence of porosity within the casting structure, demonstrating a clear relationship between local defects and local mechanical properties. This research contributes to the development of optimized castings with reduced weight and low rejection rates, enhancing the potential for aluminium alloy cast components in electric vehicles.