Management scheme for parallel connected hybrid energy storage in electric vehicles

As the electric vehicle (EV) gains traction in the modern automotive market, a focus has been placed on the development of efficient and long-lasting methods to store energy. In order to exploit the advantages of a hybrid energy storage system (HESS), new management schemes are needed which understand the mechanics of each energy storage device. Many EVs have introduced regenerative braking as a method to recharge the battery bank while in operation. Unfortunately, the combination of long duration discharge drive currents and short, high powered charging currents from regenerative breaking place batteries under enormous stress resulting in shorter lifetimes. Moreover, when the battery bank is at a high state of charge, electrochemical constraints will limit current injection during regenerative braking thus some energy is left to waste. In this work, a parallel-connected lithium ion battery bank and supercapacitor HESS demonstrates a new multi-state EV control and management scheme. Unnecessary cycling of the lithium ion battery array is reduced while the efficiency of a regenerative braking pulse is increased. The scheme is demonstrated experimentally using the DOE Hybrid Pulsed Power Characterization test profile procedure.