Charging and Discharging of Supercapacitor

Abstract

A new technology, the supercapacitor, has emerged with the potential to enable major advances in energy storage. Supercapacitors are governed by the same fundamental equations as conventional capacitors, but utilize higher surface area electrodes and thinner dielectrics to achieve greater ca- pacitances. This allows for energy densities greater than those of conventional capacitors and power densities greater than those of batteries. As a result, supercapacitors may become an attractive power solution for an increasing number of applications. A simple resistive capacitive equivalent circuit is su cient to characterize its internal behavior. The equivalent model consists of three R-C branches. The internal parameters of supercapacitor is explained by using practical charging and discharging characteristics. With the help of internal parame- ters of supercapacitor the exact behavior of supercapacitor for charging and discharging characteristics can be obtained. By changing these internal pa- rameters the required charging discharging characteristics can be achieved. To replace the battery with supercapacitor it is required to have charging and discharging characteristics of supercapacitor same as battery. To obtain same characteristics as battery with the help of supercapacitor modi cation in its internal parameters is required. And to get performance of supercapacitor same as battery it is require to have internal parameters of supercapacitor equivalent to battery. To obtain the desired value of internal parameters of supercapacitor modi cation in material used in supercapacitor is required. By choosing such material which increase the value of electrical series resis- tance (ESR) the capacitance value will decreases. So compromise has been done between the desirable characteristics and power density.