Modelling of the supercapacitors during self-discharge

The self-discharge behaviour of supercapacitors is an important factor because it determines the duration time of stored energy on open circuit. For the supercapacitor technology with activated carbon and organic electrolyte, the self-discharge is based on two mechanisms [1]. The first is due to the diffusion of ions from regions of excess ionic concentration. The second is due to the leakage of charge across the double-layer at the electrolyte-carbon interfaces. This paper treats the modelling of the supercapacitors, which takes into account the self-discharge phenomenon. Supercapacitor characterization is presented and analyzed, particularly the behaviour of self-discharge. To establish the supercapacitor model parameters, it's proposed to supplement an existing equivalent circuit model [2] by adding some new elements, which can be, describe the supercapacitor self-discharge behaviour Simulation and experimental results are presented and compared.