Battery and ultracapacitor combinations — Where should the converter go?

This paper is focused on what is being referred to now as the hybridized battery. Hybridized energy storage at the package level entails combination architectures of battery and capacitor enabled with a power electronic converter. The introduction of power electronics into the energy storage component mix brings with it considerable flexibility in decoupling the power and energy functions of storage but also introduces the new feature of advanced energy management directly into the storage system. The benefits of power electronic enabled energy storage are numerous and include greater flexibility in meeting individual application demands for burst power and for sustained energy all the while subject to an OEM specific energy management strategy. Power electronic managed energy storage not only decouples power and energy but facilitates improved reliability and life for cold temperature performance; enables the separation of Joule losses, moved from the battery and minimized in the ultracapacitor; presents the opportunity to introduce a true energy battery at lower cost/Wh without loss of high burst power; enhances the capability of energy storage to source and sink high power at end of life without over sizing the battery; sustains the capability of the energy storage to fully recuperate braking energy in a vehicle when cold and when the battery is at high state of charge.