Development of the Sealed Zinc - Silver Oxide Secondary Battery System

摘要

The reaction between Zn and oxygen was investigated during overcharge and on stand. The electrolyte level and the type of separator used in cells were the most important factors in the reaction rate. Investigation of the AgO-Ag2O hydrogen reaction showed that the rate increased with temperature, potential, the addition of Pd to the Ag and the mobility of the electrolyte. Sealed AgZn cells may be over discharged at the C/4 rate without developing excessive pressure. Electrochemically inactive or non-dischargeable zinc reacts with the oxygen generated during reversal. Physical, chemical, and electrical properties are presented for many separator and interseparator materials. Several inorganic separator materials were evaluated. Of the group, only S5520 warrants further testing. Evaluation cycling and cycle life data were obtained for 244 sealed silver zinc cells. The best results, up to 316-621/2 depth of discharge cycles, were obtained from a cell with a 62% porous positive electrode, Teflon binder, 2% HgO and 1% Emulphogene BC 840 in the negative electrode, 42% KOH, and a separator consisting of 1 turn Pellon 6/5T C19(300). Another separator system of interest consists of 1 turn Pellon 6/1T 2.2XH/2T FSC. Twenty five 41 AH silver-zinc cells were sealed in stainless steel cans. The terminal lead-through was by means of a vulcanized neoprene seal. (Author)