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Energy and Power ProductionElectrochemical Energy Storage

Status of Degradation Rates and Mechanisms in Nickel-Hydrogen Cells

Authors: L. H. Thaller; AEROSPACE CORP EL SEGUNDO CA TECHNOLOGY OPERATIONS
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.

Limitations: APPROVED FOR PUBLIC RELEASE
Description: Technical rept.
Pages: 24
Report Date: 15 APR 1998
Contract Number: F04701-93-C-0094
Report Number: A527543
Keywords relating to this report:
*FUEL CELLS
DEGRADATION
HYDROGEN
LIFE CYCLE TESTING
NICKEL
STORAGE BATTERIES
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