Life-cycle parameter identification method of an electrochemical model for lithium-ion battery pack

Abstract An electrochemical model can accurately describe both internal and external characteristics of lithium-ion batteries. However, when the model is adopted for a battery pack, the inconsistency of the cells in a pack increases the difficulty of battery modeling and parameter identification. This work develops an electrochemical model parameter identification method for a battery pack with six single cells connected in series. Capacity checking is first conducted to address the problem of the inconsistency of single cells in terms of inconsistent specified discharge cut-off voltage when an excitation operating condition is applied to the pack. Model parameters of all the cells are then obtained based on excitation-response analysis. Essential validations in terms of battery pack model simulations and the model's application in state of charge estimation during full life cycle are also provided to prove the applicability of the developed method.