Early Design Stage Evaluation of Thermal Performance of Battery Heat Acquisition System of a Hybrid Electric Aircraft

The electric energy and power storage, conversion and distribution (ESC&D) system of a hybrid electric aircraft, even at high efficiency, will reject significant heat at relatively low temperature. Thermal management systems (TMSs) can add excessive weight (heat exchangers and pumps) and impose excessive parasitic power consumption (pumps and fans) and drag (engine fan stream air and ram air) on the aircraft. Thus, effective low-weight thermal management of the ESC&D system is critical to realizing the potential benefits of a hybrid electric aircraft. This paper carries out early design stage benchmarking and evaluation of various thermal management approaches for the battery heat acquisition system of a hybrid electric aircraft. It is shown that the battery heat acquisition system based on state-of-the-art automotive electric vehicle design may be a third of the weight of the battery itself. Alternative approaches discussed here have the promise of reducing this weight by more than 60%.