Understanding and managing capacity walkdown in nickel-hydrogen cells and batteries

The findings of a recent study that investigated the impact of cycling temperature, electrolyte concentration, cobalt content of the active material, and the cycling history of the electrode on the charging potential for the beta-phase and gamma-phase materials have been incorporated into earlier studies of the capacity walkdown phenomenon. Significant amounts of capacity walkdown were found to be associated with many of the life cycle testing programs carried out at the Navy facility in Crane, IN (USA). These findings are not only helpful for understanding the mechanisms associated with capacity walkdown, but will be useful in selecting cell design factors and cycling conditions that will allow the capacity loss to be held to an acceptable value.