Modeling of a Nickel-Hydrogen Cell: Phase Reactions in the Nickel Active Material

A nonisothermal model of a nickel-hydrogen cell has been developed with the consideration of multiple phases in the nickel active material. Important mechanisms inside a nickel-hydrogen cell, such as mass balances of active species, kinetics of electrochemical reactions, and the energy balance of the whole cell, etc., have been included in the model. The model predictions under different conditions are presented and analyzed. These predictions showed that nickel phase reactions have significant influences on the behavior of a nickel-hydrogen cell. Some observed phenomena of a nickel-hydrogen cell, e.g., the capacity variation at different temperatures and the KOH concentration change between charge and discharge processes, could be reflected reasonably with the model. (C) 2001 The Electrochemical Society.