Validation test of 125 Ah advanced design IPV nickel-hydrogenflight cells

An update of validation test results confirming the advanced design nickel-hydrogen cell is presented. An advanced 125 Ah individual pressure vessel (IPV) nickel-hydrogen cell was designed for storing and delivering energy for long-term, low-earth-orbit (LEO) spacecraft missions. The new features of this design are: the use of 26% rather than 31% potassium hydroxide (KOH) electrolyte; a patented catalyzed wall wick; serrated-edge separators to facilitate gaseous oxygen and hydrogen flow within the cell, while maintaining physical contact with the wall wick for electrolyte management; and a floating rather than a fixed stack to accommodate nickel electrode expansion. The resulting improvements include extended cycle life and enhanced thermal, electrolyte, and oxygen management; and accommodation of nickel electrode expansion. Six 125-Ah flight cells based on this design are in the process of being evaluated in a LEO cycle life test