PURPOSE: To obtain an Ni-hydrogen secondary battery having a very high discharging capacitance and maintaining a high capacitance even after repeated charging-discharging.
CONSTITUTION: This is a hydrogen storage alloy having a compsn. expressed by the formula: TiaZr1-a (NibVcMndMee) [in the formula, M=one or two or more kinds of elements selected among Cr, Fe, Co, Mo, W, Al, Cu and Nb as well as 0≤a<0.60, 1.00<b<1.50, 0.10<c<0.50, 0.10<d<0.70, 0.05<e<0.30 and 1.90≤b+c+d+e≤2.30] and substantially constituted of a Laves phase only, and this is a negative electrode for an Ni-hydrogen battery using the same as negative electrode active substance. The melting of the alloy is executed by rapid solidification of 500K/sec or faster from the state of the molten soln., and after the solidification, stress relief annealing may be executed at 550 to 750°C for 1 to 4hr.
HARA MASAYUKI
KUYAMA JUNJI
KAMISHIRO KOICHI
TAKESHITA YUKITERU