Effect of design variables on the cycling characteristics of Ni-H 2 cells

The effect of two separate structures, two kinds of electrode stack configurations, and three KOH concentrations on the capacity and voltage characteristics of flight model Ni-H₂ cells was investigated. The cells were tested in a low-Earth-orbit (LEO) cycling regime at a depth of discharge of 60% of the measured capacity and 4% overcharge. The current density during discharge was 29 mA/cm². A group of four cells completed 6000 cycles with no failures. Results indicate that a lower KOH concentration decreases capacity. The discharge voltage is higher for cells with Zircar separator and 31% KOH. The end-of-discharge voltage during cycling is stable for cells with Zircar separator, due to the high electrolyte absorbency of Zircar