A Comparative Study of Equivalent Circuit Models with Diverse Nonlinear Dynamics for Li-Ion Batteries

Nonlinear processes of lithium-ion batteries have gained increasing attention due to the development of nonlinear characterization methods. However, the effect of various battery nonlinear dynamics interpretations on the accuracy of battery models has not been investigated. This paper presents a comparative study of three equivalent circuit models with distinct nonlinear dynamics for lithium-ion batteries. These three models were selected or adapted from state-of-the-art nonlinear models reported in the literature. The test data is obtained from both experiments and hardware-in-the-loop simulation. Experimental results indicate that the diffusion process must be accounted for in battery equivalent circuit models in order to achieve high accuracy throughout the entire SOC range.