THE TESTING OF HERMETIC SEALS AND SEPARATORS, POSITIVE PLATE STUDIES, AND INVESTIGATIONS ON THE UNIFORMITY OF SEALED NICKEL-CADMIUM CELLS

Cells were charged and then discharged with and without an 8 hour stand period. Capacity was decreased by an average of 9% when the cells were on open circuit for 8 hours after charge. The capacity dependence upon charge rate was determined after a 24 AH input. Findings were similar to those observed previously for 12 AH input and also for that input required to produce no significant changes in pressure. Charging 6 AH cells at -20 F and 100 ma resulted in overcharge pressures averaging about 80 PSIG. The discharge capacity at C/2 averaged 2.8 AH to 1.0 volt and 3.4 AH to 0.6 volt. The O evolution from positive electrodes was measured for stand periods ranging up to 6 months, and the experiment was repeated with stands ranging to 2.5 months. The 2 sets of data were in agreement. Discharge of the electrodes indicated a capacity loss other than that which may be accounted for by loss of O. X-ray diffaction patterns indiated greater crystallinity of electrodes discharged after being stored for 6 months at 50 C than for electrodes stored 2.5 months at 10 C. (Author)