Water-based Cooling Fluids to Mitigate the Thermal Management Challenges in New Energy Vehicles

Abstract

Thermal management is considered one of the key enablers for the adoption of New Energy Vehicles. An efficient design of an electrified vehicle’s cooling system, be it a HEV, BEV or FCEV, is of major importance to guarantee vehicle lifetime, optimize energy efficiency, enable adequate driving range and allowing high charging speed. Moreover, it is of critical importance for safety. Compared to internal combustion engine (ICE) vehicles, cooling systems for electrified vehicles have become more complex with increasing integration of a variety of parts. The cooling medium’s main function is no longer limited to cooling of the ICE; it also used to conserve and transport heat to essential powertrain parts such as the battery pack, all while electrical safety cannot be jeopardized. Many recently launched electrified vehicles successfully employ the same water-glycol based cooling liquids that are found in ICE vehicles. In light of future developments such as ultra-fast charging, advances in cooling systems and the cooling liquid are required. Recently, a clear shift from air cooling towards waterbased cooling fluids is witnessed mainly due to the strong beneficial heat transfer properties of water. For direct cooling of fuel cell stacks different changes are demanded since the upper electrical conductivity limit of the aqueous liquid compels the use of new additive technology.