Double-Side Direct Oil-Cooling Automotive Power Module: From Material Compatibility to Thermal Management

This study presents the development and evaluation of an all-oil-cooling in-wheel drive system. A novel oil coolant, Fluid B, was designed, demonstrating high flash point, low viscosity, and robust insulation properties even after extensive aging tests. The influence of molecular structure on fluid properties was explored, revealing the benefits of using a narrow-cut base oil and long main chain molecular structures. The study further utilized Hansen Solubility Parameters to enhance the understanding of swelling behavior in different oils. At last, a 6-in-1 direct oil cooling automotive power module was proposed and evaluated, achieving a significantly lower thermal resistance of 26.3 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>K/W compared to conventional water-cooling power modules. The findings indicate that through careful material compatibility study and proper thermal management, the implementation of a direct oil-cooling power module is feasible, marking a significant advance towards efficient all-oil-cooling drive systems.