An investigation of critical parameters on spontaneous combustion for lithium-ion battery using bifurcation theory.

Electric vehicles (EVs) are prevalent in the modern automotive industry, providing zero emission during their operation. However, there are numerous circumstances such as extreme temperatures and collisions, which cause the spontaneous ignition of Lithium-based batteries (LIBs), resulting in severe safety problems. Current literature mainly focuses on advancing the heat conduction of such batteries, using LIB numerical simulation based on software such as COMSOL, few explore the critical parameters, for which the spontaneous ignitions of batteries occur. Due to the extensive parameters, instability and huge computational times in running numerical simulations, it is difficult to simulate the critical parameters of LIBs. Mathematically, bifurcation theory provides a qualitative way to determine the critical parameters, which does not require complex numerical calculations to evaluate such parameters of LIB thermal runaway (TR). Henceforth, we establish two simple parallel and circular models to demonstrate how we can use bifurcation theory to determine paramount factors, paving the way for more sophisticated studies on the design of LIB cooling systems, the choice of battery materials and the curvature of LIBs to enhance their safety operations. Last but not least, the present study provides starting references for computationally extensive LIB numerical simulations.