Development of Next Generation EV Coolant

Abstract

Research indicates that there are two approaches to Electric Vehicle (EV) liquid cooling: direct and indirect. Direct liquid cooling involves direct contact between the coolant and the battery pack. Indirect liquid cooling requires a medium in between the battery pack and the coolant, preventing direct contact. Many prominent EV manufacturers have adopted indirect liquid cooling for example Tesla, and GM in North America. Currently, shelf coolants used for Internal Combustion Engines (ICE) are being used in many EV vehicles for indirect cooling. One of the challenges is absence of ASTM test methods for evaluating EV coolants. Some operators have used copper wires for generating deposits by employing voltage to test low conductivity EV coolants. Dober long ago realized that copper and aluminum will be the main components of EV engines hence used copper wire under high temp and pressure to show differentiation among coolants. The present paper focuses on Dober-in-house test Parr reactor methodology for comparing electrical conductivities, pH and additive depletion of various coolants thereby showing meaningful trends with time and temperature. This ultimately helps in developing new generation EV coolants. It is concluded that low electrical conductivity along with robust corrosion inhibition package is needed for optimum performance of EV coolants.