A fundamental study of the effects of compression on the performance of lead accumulator plates

Cycling experiments showed that the behavior of compressed test cells is more reproducible with the new separators (Amer-Sil and Daramic) than with the AGM separators used in our previous work; internal shorts did not appear. Optimum mechanical pressure was found to be close to 4 N/cm2, at which the cycle life of positive test electrodes exceeded 600 cycles and that of the negatives was more than 800 cycles, both at 100% DOD. Measurements of pressure changes in test cells with lead sheet counter electrodes showed that the volume changes of positive test electrodes follow the expected course, i.e. expansion on discharge and vice versa. The volume increase of the negatives, which may be attributed to the expander, can be prevented or even overcompensated by the applied mechanical pressure.