An electrochemical theory for repurposing battery thermal runaway as a propulsion mechanism

This study introduces a theoretical approach for generating chemical energy needed for propulsion by leveraging the thermal runaway phenomenon in lithium-ion batteries. While prior studies have focused on mechanisms and characteristics of battery thermal runaway phenomena, this work presents a concept of explicit control of thermal runaway through external voltage modulation. The control of thermal runaway is enabled by unifying electrochemical and thermochemical processes through a set of equations linking the surface capacitance, reaction rates, and heat generation. The thermochemical equilibrium analysis is conducted to examine the combustion reaction of the battery electrolyte, emphasizing the role of solid electrolyte interface (SEI) decomposition in controlling the anode-electrolyte reaction. To regulate SEI decomposition, the study demonstrates the linear heat control through the voltage modulation and introduces a method for determining potential drops near the electrodes, with surface capacitance identified as a dominant factor influencing the electrochemical reaction rates. Thus, the present results establish a theoretical foundation for repurposing battery thermal runaway as a chemical propulsion mechanism, offering dual benefits of addressing safety concerns and enabling energy conversion between electrochemical and thermochemical systems.