Figure 1. Two separate cooling systems are typically used to cool the ICE and the ETDS. A lowtemperature loop is required for the ETDS, while a high-temperature loop cools the ICE. Bonded Interfaces IGBT Ceramic Substrate Base Plate Thermal Grease Cold Plate Cooled Surface (a) Bonded Interfaces IGBT Ceramic Substrate configuration, the power modules are cooled on both sides with millimeter-sized channel geometry cold plates [figure 2(c)]. this unique cooling system provides an effective and compact cooling system that has also been employed in the 2012 toyota camry hybrid system. nrel has collaborated with industry to develop costeffective thermal management solutions to increase device and component power densities. in one project, we developed and demonstrated a general design concept that uses conventional cooling strategies (i.e., channel flow with Weg coolant) while improving the system-level semiconductor package thermal performance to improve the capability of power semiconductor devices. the patented heat-exchanger design integrated Base Plate Cooled Surface (b) Cooled Surface (a) Cold Plate Ceramic Insulator Copper Thermal Grease IGBT Copper Ceramic Insulator Cold Plate Thermal Grease Cooled Surface (c) Figure 2. Simplified schematics of the insulated-gate bipolar transistor (IGBT) bonded to various power module configurations: (a) a power module mounted on cold plate, (b) a directly cooled base plate, and (c) a double-sided cooled power module. 44 I E E E E l e c t r i f i c ati o n M agaz ine / j un e 2014 (b) Figure 3. Conceptual drawings show (a) an integrated heat spreader and heat-exchanger system to enhance heat spreading and cooling performance and (b) computational fluid dynamics simulations.