Modeling and simulation of first-order Li-Ion battery cell with experimental validation

In this paper the first-order RC equivalent circuit model (ECM) of the Lithium Ion cell is presented. This circuit can be used in real-time applications, for example, the battery management system (BMS) because is not computational complex. The model parameters are identified with experimental measurements on a real Li-Ion cell. First the discharge capacity was measured and after the cell was completely charged and discharged applying constant current pulses to determine the open circuit voltage (VOC) and the parameters for the equivalent circuit components. For one ECM the parameters are calculated using one discharge pulse which was applied at approximatively 60% state of charge and for the second model the circuit parameters are calculated for each discharge pulse and saved in a look-up-table depending on the state of charge. For model validation was applied a charge/discharge scenario and the results show a good agreement between the battery voltage and the ECM voltage.