Effects of cooling rate during casting on performance of metal hydride electrodes and nickel-metal hydride batteries

摘要

In this work , three Mm(Ni-Co-Mn-Al)_5 alloyswith the same formula were produced by vacuum inductionmelting and casted at different cooling rates: normal cooling, fastcooling, rapid quenching. In addition, a protion of the rapidlyquenched alloy was annealed. The crystallographic and structuralproperties and the electrochemical performance of these materialswere characterized. For all the as-cast alloys, cooling rate did notsignificantly affect their activation provess and cycle life. Incontrast, the alloy, which was rapidly quenched and then annealed,displayed a longer cycle life. However, it required a long activationprocess to achieve its maximum capacity. The effects ofmetallurgical processes on the sealed cell performance such ascycle life, internal gaseous pressure after charging, and storagebehavior after formation were also examined. 1999 ElsevierScience S.A. All rights reserved.