| 摘要 |
PURPOSE: To suppress pulverization of a rare earth element base hydrogen storage alloy powder with progress in charge/discharge cycle, by limiting atomic rate in the rare earth element base hydrogen storage allay, which is contained in a negative electrode and expressed by a prescribed general formula, within a fixed prescribed range. CONSTITUTION: A negative electrode containing rare earth element base hydrogen storage alloy expressed in a general formula, Lau Ndv M(1-u-v) At is provided to suppress pulverization of alloy power in the negative electrode with progress in a charge/discharge cycle. In this case, M is formed from at least one kind selected from rare earth elements except La and Nd, A is formed from Ni singly or a plural components of at least, one kind selected from Co, Mn, and AN, and Ni, and u, v, and t are expressed in atomic rate 0.4<=u<=0.70, 0.20<=v<=0.50, 0.80<=u+v<=l.00, 4.80<=t<=5.50 respectively. As a result, deterioration of the negative electrode is suppressed so that the charge/discharge cycle life of the battery can be improved and development rate of pulverization can be kept uniform, and ununiformity of the charge/discharge cycle life can be reduced. |
