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Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight battery cellsA breakthrough in the low-earth-orbit (LEO) cycle life of individual pressure vessel (IPV) nickel hydrogen battery cells is reported. The cycle life of boiler plate cells containing 26 percent potassium hydroxide (KOH) electrolyte was about 40,000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH. The effect of KOH concentration on cycle life was studied. The cycle regime was a stressful accelerated LEO, which consisted of a 27.5 min charge followed by a 17.5 min charge (2 x normal rate). The depth of discharge (DOD) was 80 percent. The cell temperature was maintained at 23 C. The next step is to validate these results using flight hardware and real time LEO test. NASA Lewis has a contract with the Naval Weapons Support Center (NWSC), Crane, Indiana to validate the boiler plate test results. Six 48 A-hr Hughes recirculation design IPV nickel-hydrogen flight battery cells are being evaluated. Three of the cells contain 26 percent KOH (test cells) and three contain 31 percent KOH (control cells). They are undergoing real time LEO cycle life testing. The cycle regime is a 90-min LEO orbit consisting of a 54-min charge followed by a 36-min discharge. The depth-of-discharge is 80 percent. The cell temperature is maintained at 10 C. The cells were cycled for over 8000 cycles in the continuing test. There were no failures for the cells containing 26 percent KOH. There were two failures, however, for the cells containing 31 percent KOH.
Document ID
19910053453
Document Type
Conference Paper
Authors
Smithrick, John J. (NASA Lewis Research Center Cleveland, OH, United States)
Hall, Stephen W. (U.S. Navy, Naval Weapons Support Center Crane, IN, United States)
Date Acquired
August 15, 2013
Publication Date
January 1, 1990
Subject Category
SPACECRAFT PROPULSION AND POWER
Meeting Information
Intersociety Energy Conversion Engineering Conference(Reno, NV)
Distribution Limits
Public
Copyright
Other