Thermal Dynamics and Lithium Plating Detection in High-Power Li-Ion Batteries for eVTOL Applications

Abstract

The rapid electrification of aerial transportation is driving the need for high-performance Li-ion batteries that can operate reliably under stringent thermal and safety constraints. The unique mission profile of electric Vertical Take-off and Landing (eVTOL) aircraft necessitates a focused investigation into the thermal behavior and safety characteristics of these batteries. In this study, operando isothermal microcalorimetry is employed to examine the thermal evolution of Li-ion batteries under cycling conditions representative of eVTOL operations. These findings reveal that high-power discharge events—such as those during take-off and landing—shift the thermal response toward exothermic behavior, in contrast to the typically endothermic response expected under near-equilibrium cycling conditions. Additionally, the results suggest that advanced electrolyte formulations may help suppress excess heat generation, thereby improving battery safety. Notably, the calorimetric results exhibit a distinct thermal signature associated with lithium plating, offering a potential diagnostic for detecting Li plating during eVTOL operation. Overall, this study demonstrates the utility of isothermal microcalorimetry as a valuable tool for assessing thermal risks in Li-ion batteries for eVTOL applications, and highlights the importance of targeted design strategies to mitigate safety hazards during high-power demand scenarios.