Heat spreading performance of SiC-based power module with bonded vapour chamber for electric powertrain integration

After evolving side by side over the past three decades, insulated gate bipolar transistors (IGBTs) and metal-oxide-semiconductor field-effect transistor (MOSFETs) become two main options in high power semiconductor market of Hybrid Electric Vehicle (HEV) or Battery Electric Vehicle (BEV) systems. Recent improvements on high power performance are focused on the reduction of power losses and the enhancement of system reliability. Power losses of Si-based semiconductor are dissipated in the form of heat, which must be transferred away from the switching junction effectively. In this paper, we evaluate the new vapour chamber wick design and its heat spreading performance on a SiC-based MOSFETs, the results could be used as guides in order to provide a solution to tackle with thermal imbalance incurred by switching current. The selected cases showed that Silicon carbide (SiC) based MOSFETs could operate at more uniform temperature gradient with minimum 1.4 degrees C temperature difference across the whole bonding interfaces, and hotspots can be constrained below 120 degrees C by means of phase changing cooling methods. In addition, the replacement of conventional baseplate by vapour chamber could further reduce overall thermal resistance from junctions to coolant fluids. The simulation results show that wicks design with sintering methods could perform better than groove and mesh design in such high power application. At last, under low coolant flow rate chanlleges at 0.5 l/min, an integrated vapour chamber with ellipse pin-fin 16 x 20 is preferred with achieved temperature at 123.3 degrees C.