Status of Degradation Rates and Mechanisms in Nickel-Hydrogen Cells PDF Download
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Author: L. Thaller Publisher: ISBN: Category : Languages : en Pages : 24
Book Description
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.
Author: L. Thaller Publisher: ISBN: Category : Languages : en Pages : 24
Book Description
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.
Author: Lawrence H. Thaller Publisher: AIAA ISBN: 9781884989131 Category : Technology & Engineering Languages : en Pages : 212
Book Description
The review and analysis reported here are the outcomes of a project carried out from 1998-2001 within the Energy Technology Department of the The Aerospace Corporation to examine the available results of different nickel-hydrogen life testing programs that had been or were being carried out for low Earth orbit (LEO) applications. The cycling programs, some of which are still in progress, were conducted under different sponsorships and carried out at different testing facilities.
Author: Publisher: ISBN: Category : Languages : en Pages : 22
Book Description
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.
Author: Supramaniam Srinivasan Publisher: Springer Science & Business Media ISBN: 0387251162 Category : Science Languages : en Pages : 707
Book Description
This concise sourcebook of the electrochemical, engineering and economic principles involved in the development and commercialization of fuel cells offers a thorough review of applications and techno-economic assessment of fuel cell technologies, plus in-depth discussion of conventional and novel approaches for generating energy. Parts I and II explain basic and applied electrochemistry relevant to an understanding of fuel cells. Part III covers engineering and technology aspects. The book is useful for undergraduate and graduate students and scientists interested in fuel cells. Unlike any other current book on fuel cells, each chapter includes problems based on the discussions in the text.
Author: Albert H. Zimmerman Publisher: ISBN: Category : Languages : en Pages : 40
Book Description
The rapidly fluctuating pressure environment that exists in today's nickel-hydrogen battery cells during high rate charge discharge operation can potentially act as an important source of stress to the active materials in the nickel electrodes. This study examines the coupling between the rapidly fluctuating pressure environment of hte nickel hydrogen cell and degradation of the nickel electrodes arising from expansion and contraction of the active materials. A model is developed to describe this coupling, and the sensitivity of the coupling to the parameters in the model is analyzed. The model is used to determine modes of nickel hydrogen cell operation for which the pressure environment is particularly critical in terms of potential degradation. The results indicate that cell operation involving rapid cycling or quite large dynamic operating pressure ranges may cause significant stress to the nickel electrodes, and may be an important component in degradation and failure rates. Finally, cell tests are suggested that should allow the effect of the nickel-hydrogen cell pressure environment on performance to be determined. Keywords: Nickel electrode, Nickel hydrogen, Degradation, Pressure, Hydrogen.
Author: L. Thaller
Author: L. Thaller
Author: Lawrence H. Thaller
Author: Lawrence H. Thaller
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Author: 
Author: Supramaniam Srinivasan
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Author: 
Author: Albert H. Zimmerman
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