A method for performance evaluation and optimal sizing of the supercapacitor module by the Electrochemical Impedance Spectroscopy

Supercapacitor, a pollution free energy storage device with high power density, long life span and low internal impedance, is suitable for applications that need compensating for the output fluctuation of new and renewable energy source or shaving off the peak power demand. In particular, it is anticipated to play an important role in increasing system efficiency and reliability by reducing the peak load for the batteries and fuel cells, and recycling regenerated energy in applications such as PEV (pure electric vehicle), PHEV (plug-in hybrid electric vehicle) and FCV (fuel cell vehicle). However, as supercapacitors are produced in various voltages and capacitances by the manufacturers, accurate criteria for performance evaluation are essentially needed due to high unit price and it is also very important to raise system economic advantage by organizing optimal module on such basis. In this paper criteria for better selection of the supercapacitor through EIS (electrochemical impedance spectroscopy) experiment are presented and based on the experimental results optimal method of designing supercapacitor module applied to electric vehicle is proposed. The validity of the proposed criteria is proved through the simulation using Japan 10-15 urban driving cycle.