Low-Temperature Failure Mode for Nickel-Hydrogen Cells
Abstract
A mechanism has been proposed that can potentially lead to rapid degradation and failure of nickel-hydrogen cells as a result of electrolyte freezing. It has been shown that there are chemical processes that can occur within the operating nickel-hydrogen cell that can raise the electrolyte freezing point in some cell designs up to the -5 to -10 degrees C operational temperature range that cells can experience in some applications. The model that describes this failure mode suggests that the operational conditions where this failure mode is most likely to be seen is during long-term trickle charge at cold temperatures. It is recommended that nickel-hydrogen cell designs that are required to operate at temperatures well below 0 degrees C should be evaluated for long-term degradation 10 degrees C below their lowest expected operating temperature during extended trickle charge. This will assure that there is sufficient temperature margin to accommodate thermal variability between the individual cells in a battery power system.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 05, 2005
- Accession Number
- ADA438233
Entities
People
- Albert H. Zimmerman
Organizations
- The Aerospace Corporation