Liquid Cooling Systems for Batteries of Electric Vertical Takeoff and Landing Aircraft

Abstract

Batteries are the lynchpin of electric vertical takeoff and landing (eVTOL) aircraft, and the high discharge rates pose a critical challenge to the battery thermal management system (BTMS). This work presents a channeled liquid cooling technology-based BTMS for eVTOL aircraft. During the flight, the heat generated from the batteries is partly extracted by circulating liquid coolant within a wavy channel (WC) attached firmly to the battery cells. The heat is then transported into a plate-fin compact heat exchanger (HEX), where all the heat is dissipated into the atmosphere. We report sensitivity analyses of the HEX model to shed light on the impact of the relevant design parameters on the BTMS size, weight, and power. We also examine critical parameters of the coupled WC-HEX BTMS in a one-dimensional off-design analysis. We demonstrate that the liquid cooling system can maintain the battery operating temperature within acceptable levels with a mass of less than 20% of the battery pack mass. Battery degradation using the liquid cooling system is reduced by over three times compared to an air-cooled system for both tilt-wing and lift+cruise eVTOL aircraft.