Optimized Operation of a Hybrid Energy Storage System with LTO Batteries for High Power Electrified Vehicles

Hybridization of the energy storage system in an electric vehicle offers the flexibility to dimension energy content and power capability independently. The proposed hybrid energy storage system, with one dc-dc converter, connecting either the high energy or high power pack with the inverter dc-link, can lead to weight and volume savings in comparison to a single battery pack topology. An energy management system controls the power flow. This paper presents a tool for the design and simulation of hybrid energy storage systems. Dynamic programming is used to optimize the power flow for the overall system efficiency. Multiple scenarios are presented to show the influence of the driving profile on the efficiency of the storage system in an electric vehicle designed for high power racing applications.