Accelerating the numerical solution of thermal runaway in Li-ion batteries

Abstract

Computational modeling and simulation of thermal runaway in Li-ion batteries is an effective tool to understand safety concerns associated with Li-ion batteries. However, thermal runaway models are often computationally expensive due to the highly non-linear and coupled nature of the equations involved. Therefore, accelerating the numerical computation of thermal runaway in Li-ion batteries while maintaining computational accuracy and stability is of utmost practical importance. This paper compares several time integration schemes to solve the highly non-linear and stiff differential equations that govern thermal runaway in Li-ion batteries. The schemes are implemented to solve a lumped capacitance thermal runaway model for a representative thermal abuse scenario. Results showed that explicit methods produce similar accuracy as implicit methods at a fraction of the computational cost while maintaining stability even for stiff thermal runaway scenarios. For example, a one-stage and a two-stage explicit Runge-Kutta method resulted in two orders of magnitude lower computational time than the implicit methods while maintaining a similar level of accuracy. By investigating the computational performance of various numerical schemes for analyzing thermal runaway, this work contributes towards improved safety of energy conversion and storage in Li-ion batteries.