Parameter estimation for equivalent electrical model of lithium-ion cell

This paper presents an estimation procedure of equivalent electric circuit parameters of a lithium-ion cell using data from a pulse charge/discharge test. An extraction process of the model parameters is based on a transient voltage response of relaxation process following a current pulse. The entire procedure is straightforward and there is no restriction in a number of parallel RC-branches in the electrical model. Convergence problem of the parameter estimation process, existing in classic solutions, is solved by application of a particle swarm optimization method (PSO). The entire parameter identification procedure is performed in automated way in order to reduce time required to obtain a sufficient set of parameter values for different states of charge. The model is verified based on experimental data.