A thermal-electrochemical-mechanical coupled model based on non-equilibrium thermodynamics of Li-ion batteries

Abstract

According to non-equilibrium thermodynamics in Li-ion batteries (LIBs), the complicated coupling relations exist among the electric flux, ion flux, heat flux and so on. In this paper, we propose a thermal-electrochemical-mechanical coupled model (TECM model) which could predict capacity loss, concentration evolution, thermal runaway and mechanical degradation by considering the thermal diffusion, thermoelectric, Dufour effects, etc. The correlation between prediction difference and discharging rate is further studied. The results show that TECM model is more suitable for electrical prediction under variable temperature conditions and the thermal prediction accuracy is higher, which is beneficial to thermal management. Also, TECM model can describe the multiple physics fields in one calculation. This model provides an approach to investigate the thermal, electrochemical and mechanical behaviors in LIBs.