Thermal and Thermomechanical Performance Enhancement of Electric Vehicle Power Modules Utilizing Diamond-Copper Composite Interposers

As the power density of electric vehicles continues to increase, the investigation of double-sided-cooling (DSC) modules are increasingly gaining attention as a significant area of research. However, Mo, as a traditional interposer material, exhibits relatively low thermal conductivity despite its good coefficient of thermal expansion (CTE) matching with power chips, resulting in elevated junction temperatures. In this paper, we introduce a diamond-copper composite material (DC40, with a diamond volume fraction of 60%) interposer possessing high thermal conductivity and low CTE to mitigate module junction temperatures and thermomechanical stresses. Thermal and thermal cycling simulation results indicate that compared to modules employing Mo and Cu interposers, under a total power consumption of 100 W, the maximum junction temperatures decrease by 1.92 °C (1.52%) and 9.49 °C (7.08%) respectively; the power handling capacity of the chip increases by 21.5 W (14.3%) and 31.0 W (22.0%) respectively; The lifetime of the DC40 interposer DSC module is nearly equivalent to that of the Mo interposer and shows a 166.6% increase compared to the Cu interposer.