A tabulation method of Li-ion Thermal Runaway mechanisms for the acceleration of high dimensional simulations

Abstract

High-Fidelity numerical simulations of the Thermal Runaway (TR) phenomenon on lithium-ion batteries (LIB) depict stiff system of equations that need to be solved with extremely low time-steps to ensure numerical stability. In the present study, a methodology is presented to improve computational times and convergence of three-dimensional studies. A tabulation approach of the developed chemical kinetics models on the literature is presented to avoid the resolution of the set of Ordinary Differential Equations (ODE) that define the self-heating behavior of LIB under thermal degradation conditions. The desired tables have been obtained through 0-dimensional models for three different cathode materials (${\mathrm{LiCoO}}_2$, NMC111 and NCA) and the TR mechanism have been replicated with the tabulation method firstly through the 0-dimensional approach and then translated to a 3-dimensional model to ensure its functionality and assess the minimum time-step needed for performing TR simulations. The results through the tabulation method replicate almost exactly the onset temperature for the three cathode chemistry both 0-dimensonally and 3-dimensionally. Additionally, a significant speed up is reported for TR propagation studies performed, allowing time-steps three orders of magnitude larger than through traditional methods while ensuring numerical stability.