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Koh concentration effect on the cycle life of nickel-hydrogen cells. 4: results of failure analyse
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Lim, H. S. Verzwyvelt, S. A. |
| Copyright Year | 1989 |
| Description | Effects of KOH concentrations on failure modes and mechanisms of nickel-hydrogen cells were studied using long cycled boiler plate cells containing electrolytes of various KOH concentrations ranging 21 to 36 percent. Life of these cells were up to 40,000 cycles in an accelerated low earth orbit (LEO) cycle regime at 80 percent depth of discharge. An interim life test results were reported earlier in J. Power Sources, 22, 213-220, 1988. The results of final life test, end-of-life cell performance, and teardown analyses are discussed. These teardown analyses included visual observations, measurements of nickel electrode capacity in an electrolyte-flooded cell, dimensional changes of cell components, SEM studies on cell cross section, BET surface area and pore volume distribution in cycled nickel electrodes, and chemical analyses. Cycle life of a nickel-hydrogen cell was improved tremendously as KOH concentration was decreased from 36 to 31 percent and from 31 to 26 percent while effect of further concentration decrease was complicated as described in our earlier report. Failure mode of high concentration (31 to 36 percent) cells was gradual capacity decrease, while that of low concentration (21 to 26 percent) cells was mainly formation of a soft short. Long cycled (25,000 to 40,000 cycles) nickel electrodes were expanded more than 50 percent of the initial value, but no correlation was found between this expansion and measured capacity. All electrodes cycled in low concentration (21 to 26 percent) cells had higher capacity than those cycled in high concentration (31 to 36 percent) cells. |
| File Size | 59895 |
| Page Count | 1 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19890013633 |
| Archival Resource Key | ark:/13960/t3mw7b99b |
| Language | English |
| Publisher Date | 1989-01-01 |
| Access Restriction | Open |
| Subject Keyword | Energy Production And Conversion Nickel Hydrogen Batteries Concentration Composition Low Earth Orbits Chemical Effects Failure Analysis Life Durability Failure Modes Electrolytes Potassium Hydroxides Boiler Plate Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
