Generalized Self-discharge Model for a Series of Supercapacitors

Supercapacitors (SC) have gained a lot of attention as energy storage and power supply option due to its several advantageous characteristics and broad applicability. Self-discharge remains one of the key issues while using supercapacitor as energy storage device, especially for low duty cycle applications. The SC terminal voltage gets affected by the self-discharge of the device under no-load condition. The self-discharge of SC depends on its charging-rate and the capacitance value. In this paper, we propose a computationally efficient empirical model for characterizing the self-discharge response of a series of supercapacitors. The empirical model takes the effect of SC charging-rate and capacitance into account. In the process, we propose a generalized model parameter identification scheme based on least-square error. Then, we demonstrate the effectiveness of the proposed model and the identification scheme by performing experimental study on a number of commercially available Maxwell HC series SCs. we conduct the experimental study for different level of charging-rate from 1C to 50C. The experimental validation is found to be satisfactory and promising.