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

This paper presents the concept design, material reliability, and thermal management of the direct oil-cooling automotive power module we developed. This type of module faces several significant challenges compared to the conventional water-cooling power module, such as copper lead corrosion, rubber swelling, and high thermal resistance. We therefore prototyped a double-side direct oil-cooling power module to investigate the reliability and thermal resistance performance. Our findings showed that mineral oil-based coolant and insulating ester oil have outstanding reliability and compatibility to power module materials. A 31% reduction of thermal resistance at 10L/min 25°C was obtained, which is much lower than even referenced double-side water-cooling power modules, thus demonstrating the feasibility of direct oil-cooling automotive power electronics.