GB1328788A - Rechargeable batteries with zinc electrodes - Google Patents

Abstract

1328788 Metal-air secondary batteries ELECTRICITY COUNCIL 22 Oct 1970 [22 Oct 1969] 51837/69 Heading H1B In a rechargeable zinc-air or other battery having an electrode on which metal is deposited from an electrolyte during recharging, a gas such as air or nitrogen which does not interfere with the electro-chemical processes in the battery is bubbled through the electrolyte to create turbulence during recharging and thus minimize the growth of dendritic, mossy, or nodular metal on the electrode. The electrolyte may be an alkaline zincate with a zinc electrode, and the bubbling may be continued during discharging when it is stated to improve the electrode behaviour and reduce passivation. Fig. 2 shows a cell comprising an insulating air-distributer block 10 which includes a duct 11 connected to orifices (12, Fig. 1, not shown) which are spaced along the block and allow air to bubble between electrodes 16, 17. The electrodes 16, 17 are raised on insulating strips 18, 19 to ensure that each electrode is in a uniformly turbulent region. In Fig. 3, a battery comprising seventy zinc-air cells 20 is supplied with air from a pump 64 via a manifold 61 and individual cell inlet pipes 21. Electrolyte is circulated by a pump 63 through individual pipes 41, 65 to and from a cooler-filter 62. A continuous electrolyte path between cells is avoided by bubbles in the pipes 41 and by suitable sizing of the pipes 65. Air is vented at 69. The circulation of electrolyte may alternatively be effected by the passage of bubbles through the pipes to the filter.