Patrick G. Grimes

Zinc-bromine battery design for electric vehicles

Design projections for zinc-bromine batteries are attractive for electric vehicle applications in terms of low manufacturing costs (

Shunt Current Control in Electrochemical Systems Theoretical Analysis

28/kWh) and good performance characteristics. Zinc-bromine battery projections (60-80 Wh/kg, 130-200 W/kg) compare favorably to both current lead acid batteries and proposed advanced battery candidates. The performance of recently developed battery components with 1200 cm2electrodes in a 120V, 10 kWh module is described. Similarly constructed smaller scale (600 cm2) components have shown lifetimes exceeding 400 cycles and the ability to follow both regenerative braking (J227aD) and random cycling regimes. Initial dynamometer evaluations of full scale 20 kWh batteries is expected in early 1984.

Shunt Current Control Methods In Electrochemical Systems — Applications

Electrochemical systems with electrolytes common to all series cells have been plagued with the effects of currents shunting through the common electrolyte. Shunt currents can cause non-uniform cell performance, system corrosion and hydraulic malfunction. A mathematical analysis of shuntage has lead to development of electrical methods for elimination of the shuntage effects. Passage of appropriate currents through the common electrolyte will null the voltage gradients which normally would produce shuntage.

A Simple Model of Exxon’s Zn/Br 2 Battery

Shunt current effects in common electrolyte series-connected cell systems can be eliminated by passing an appropriate current through the common electrolyte manifolds or channel interconnects. Electrical shunt current control theories have been verified and the techniques have been applied to batteries and electrolysis systems. The technique appears to be generally applicable to electrochemical systems.

Shunt current elimination

A simple model of Exxon’s Zn/Br2 battery is predict the energy efficiency of the battery for resistivities and cell geometries. Efficiencies percent are predicted by the model.