A novel order-reduced thermal-coupling electrochemical model for lithium-ion batteries

Although the single-particle model enhanced with electrolyte dynamics (SPMe) is simplified from the pseudo-two-dimensional (P2D) electrochemical model for lithium-ion batteries, it is difficult to solve the partial differential equations of solid-liquid phases in real-time applications. Moreover, working temperatures have a heavy impact on the battery behavior. Hence, a thermal-coupling SPMe is constructed. Herein, a lumped thermal model is established to estimate battery temperatures. The order of the SPMe model is reduced by using both transfer functions and truncation techniques and merged with Arrhenius equations for thermal effects. The polarization voltage drop is then modified through the use of test data because its original model is unreliable theoretically. Finally, the coupling-model parameters are extracted using genetic algorithms. Experimental results demonstrate that the proposed model produces average errors of about 42 mV under 15 constant current conditions and 15 mV under nine dynamic conditions, respectively. This new electrochemical-thermal coupling model is reliable and expected to be used for onboard applications.