Life Test of 76-Ah Nickel-Hydrogen Cell Designs After 14 Years of Storage

摘要

A matrix of twelve nickel-hydrogen cells were built in 1988 to develop and validate the Man Tech nickel-hydrogen cell design that has subsequently been used in a wide range of space applications. This cell matrix included three design variations: precharge (hydrogen or nickel), electrolyte concentration (31 % or 38%), and electrolyte amount (drained or drained plus 20 cc). In 2003, eight of these cells were put into a life test following 14 years of continuous discharged storage to evaluate the effects of long-term storage on the cycle life of each design variant. Two of the cells have failed, and several of the other cells have shown evidence of degradation to date after more than six years of cycling. All the cells that have failed or degraded are those with the higher electrolyte concentration, which is a design variant that was abandoned in 1989 because of its lower expected life capability. The six non-failed cells, including two cells representative of the final ManTech design that has been used for decades, continue to cycle in this life test.