Modeling the Influences of Cells Characteristics in Battery Bank

this paper presents a modeling tool based on Matlab/Simulink, which is used for determining the State of Charge of Li-ion battery packs composed of cells with different characteristics, due to aging or different nominal capacity of the cells. The purpose of this model is to simulate the output voltage in a series-connected battery bank. This model uses reference data base with multiple discharge curves, obtained at different C - rates. That makes the model applicable for much complex battery pack models, made out of many cells and branches. The presented model allows the state of charge of a battery to be obtained for different magnitudes of the current, on the base of interpolations. It is also considered the change in the usable capacity of the battery by discharging it with different currents, proportional to the C-rate of the battery. The model is validated by experimental results.