Design of Bipolar, Flowing Electrolyte Zinc-Bromine Electric Vehicle Battery System

Abstract

The integration of bipolar, flowing electrolyte zinc-bromine technology into a viable electric vehicle battery system requires careful analysis of the requirements placed on the battery system by the EV power train. In addition to the basic requirements of an appropriate battery voltage and power density, overall battery system energy efficiency must also be considered and parasitic losses from auxiliaries such as pumps and shunt current protection minimized. An analysis of the influence of these various factors on zinc-bromine EV battery system design has been carried out for two types of EV propulsion systems. The first of these is a nominal 100V dc system, while the second is a high voltage (200V dc) system as might be used with an advanced design ac propulsion system. Battery performance was calculated using an experimentally determined relationship which expresses battery voltage as a function of current density and state-of-charge. Based on these studies, low profile, 12 dm/sup 2/ bipolar cell components have been developed which are readily incorporated into a variety of motive power and stationary energy storage system designs.