Overview of Nickel Metal Hydride Battery Technology for Aerospace Applications

摘要

For thirty years, the scientific community has investigated using intermetallicmetal hydrides as hydrogen reservoirs and electrodes for secondary batteries. They are now replacing nickel-cadmium batteries in small electronics and may become attractive for aerospace applications. Metal hydride batteries do not require high-pressure containers, and prismatic cell designs are possible. With alloying, a wide range of operational temperatures can be achieved; however, large batteries require thermal control to dissipate and supply heat during high-rate charging and discharging. Recent investigations have concentrated on optimizing electrode capacity and cycle life by manipulating alloy compositions, microstructures, particle sizes, crystallinity, and surface chemistry. Despite intensive efforts, the discharge capacity of the metal hydrides has not improved beyond 250-400 mAh/g, and inherent deterioration processes apparently related to the formation of the hydride phase make metal hydrides unreliable choices for satellite applications demanding more than 500-2000 cycles. Additionally, the long-term effects of exposure of these materials to the potassium-hydroxide electrolyte during low-cycle, long-life missions is not known. This review surveys the status of research and commercial development of metal-hydride cells and evaluates the potential advantages and applications of metal-hydride batteries for aerospace use.