Fifth-order resistance-capacitance-based optimal equivalent circuit model of lithium-ion batteries with improved transient search optimization algorithm

This research proposes an optimal equivalent circuit model based on fifth-order resistance-capacitance charging dynamics for lithium-ion batteries (LIBs). The proposed battery model not only demonstrates the complexity of LIB modeling but also facilitates accurate modeling. It incorporates detailed charging dynamics and the effect of battery fading under variable temperatures. A transient search optimization (TSO) algorithm equipped with chaotic maps is used for minimizing the objective function, improving the agents' location during initialization. Sum of square error of determined and measured voltages is selected as the fitness function. Validity of the proposed model is tested on several LIBs in industrial applications, and numerical results are compared with experimental results from an INR21700-30T, 3 Ah, Samsung LIB. The effectiveness of the chaotic TSO-based battery model is tested by comparing its numerical results with those of conventional and metaheuristic algorithm-based models. The findings indicate that the chaotic TSO algorithm can generate a detailed and accurate battery model.