A ZINC AIR CELL EMPLOYING A PACKED-BED ANODE

A cell with a particulate zinc electrode and a monofunctional air electrode has been studied on a laboratory scale. The cell has the feature of relying on solutal natural convection, rather than a pump, for electrolyte circulation. Cells of 80 and 400 cm2 (air electrode area) have been discharged at constant or stepped current. In two cases cell discharge was halted and restarted after many hours with little or no impact on cell voltage. Based on the laboratory data a preliminary design of a 32 k Wh (115 MJ) battery was completed. The projected specific energy of this cell is 79.2 Wh kg-1 (637 kJkg-1), while the peak specific power is 111 W kg-1 (20% depth of discharge), meeting of the US Department of Energy targets for a battery for an electric van.