An Accurate Fractional Order Model of Lithium-ion Battery

The paper concentrates on formulating a straightforward model capable of accurately predicting the state of charge (SOC) for batteries. The introduction of a fractional order capacitor to depict the open circuit voltage contributes to the precision of the model. The determination of parameters for the fractional order model through constant current charge/discharge tests is also discussed. A simple model representing the relationship between the impedance parameter and nonlinear battery voltage is deduced. The parameter extraction of the model is done by employing a technique based on nonlinear least squares curve fitting This method allows for the identification and analysis of both the unknown impedance parameters and the fractional order parameter ‘$\alpha$’. The model is validated using the voltage-time graph of battery obtained from the constant current charging test.