Active Cell Equalization Scheme for Performance Enhancing a Li-ion Capacitor Energy Management System

This paper proposes an improved lithium-ion capacitor (LIC) management system (LICMS), that can provide active LIC’s cells equalization and thus, enhance the performance of the energy storage system. The central idea of the suggested method is based on the control of the LIC cells’ current of each stack, by utilizing an advanced cell equalization topology in order to adjust the cell balancing current. An easy to apply cell equalization algorithm is proposed so as the LIC cells can be effectively equalized during the charging procedure. The state of health (SoH) of the LIC cells are also monitored by a SoH diagnostic algorithm, which can provide the accurate estimation of their internal resistance and the energy capacity. The accuracy and the practicality of the proposed technology along with the cell equalization and SoH diagnostic algorithms have been experimentally validated on a LICMS of three series connected cells.