Novel parameter identification method for lithium-ion batteries based on curve fitting

This paper describes a new curve-fitting lithium-ion battery parameter identification method for equivalent circuit models. The current pulse/relaxation test is carried out and the corresponding terminal voltage is used for extracting the battery model parameters. Analysis and fitting of the waveform is performed for both pulse and relaxation periods without assuming the initial conditions of the associated RC branches. This approach is demonstrated for 2nd order model using commercial battery cell and model results are presented and compared against experimental finding revealing a good agreement.