Institute of Electrical & Electronic Engineers
In spite of extensive research it is still quite expensive to store electrical energy without converting it to a different form of energy. As of today, no single type of Electrical Energy Storage (EES) element can fulfill all the desirable features of an ideal storage device, e.g., high-efficiency, high-power/energy capacity, low-cost, and long-cycle life. A Hybrid EES system (HEES) consists of two or more heterogeneous EES elements, realizing the advantages of each EES element while hiding their weaknesses. HEES systems exhibit superior performance compared with homogeneous EES systems when appropriate charge allocation and replacement policies are developed and used.