Life testing of space nickel-hydrogen battery cells

Flight quality space nickel-hydrogen battery cells have been on continuous cycle life testing at Eagle-Picher since early 1982. There are currently over one hundred flight-type nickel-hydrogen cells on life test in ten separate tests. Cells are being cycled under several different regimes, including low Earth orbit (LEO), geostationary Earth orbit (GEO), accelerated LEO, and accelerated GEO. The nickel-hydrogen testing database is described. Cells are being operated at depths of discharge (DODs) ranging from 15% to 75% DOD. Cells under test range in capacity from 30 Ah to 80 Ah. Cells have currently accumulated 69000 accelerated LEO cycles at 15% DOD, 41000 real-time LEO cycles at 30% DOD, 12000 real-time LEO cycles at 50% DOD, and 28000 cycles under a real-time LEO profile. GEO cycle life testing has accumulated 19 eclipse seasons at 75% DOD maximum. Prismatic aerospace nickel metal hydride cells have completed over 6400 LEO cycles at 40% DOD.<>