Status of Degradation Rates and Mechanisms in Nickel-Hydrogen Cells
Abstract
The usable energy density of nickel-hydrogen cells intended for low Earth orbit (LEO) applications can be significantly increased by cycling them to deeper depths of discharge (DODs). In reviewing the existing life cycle databases, the cycle life has been found to vary from less than 1000 cycles to more than 50,000 cycles when cells were cycled to 60% DOD. The causes for this wide disparity occur during the four major phases in a cell's life: (1) design, (2) manufacturing, (3) storage, and (4) life cycle testing. This report will focus on how the conditions selected for life cycle testing can have a significant impact on the usable life of a cell. Cycle life can be significantly reduced when recharge conditions are selected that accelerate the degradation rates of the naturally occurring degradation mechanisms. By paying close attention during the design, manufacturing, and storage phases, cycle lives can be dramatically improved when accompanied by appropriate recharge conditions. The objective of this study is to examine the cycling potential of nickel-hydrogen cells when cycled to 60% DOD.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 15, 1998
- Accession Number
- ADA345725
Entities
People
- L. H. Thaller
Organizations
- The Aerospace Corporation