LEO test data for 81 Ah FNC cells

Fiber-nickel cadmium (FNC) cells are being developed as a higher performance alternative to traditional Ni-Cd space cells and as a lower cost alternative to nickel-hydrogen cells. Features unique to these cells include fiber electrodes, a split-negative design, and a high ratio of electrolyte and negative capacity compared to rated capacity for increased reliability. Five 81 Ah FNC cell packs have been subjected to accelerated LEO testing for more than two years. Two packs have surpassed 18000 cycles at 35% DOD without failure and one pack cycled at 60% DOD is approaching 10500 cycles with zero failures. Charge and discharge voltages, pressure, temperatures, and integrated charge ratios are presented. Capacity test results are described. The effect of DOD and temperature on cycle life is explored