To provide new application regarding a low Co hydrogen storage alloy in which the content of Co is extremely low.
As the application of an alloy which can be expressed by the general formula of MmNia Mnb Alc Cod (wherein, Mm is misch metal, and 3.7≤a≤4.7, 0.3≤b≤0.65, 0.2≤c≤0.5, 0<d≤0.65, and 4.9≤a+b+c+d≤5.5), and in which the amount of corrosion at the time when a cycle test of 500 cycles is performed in the region where the hydrogen storage content (H/M) is 0.4 to 0.6 in a prescribed test A, use for a battery charged/ discharged in the central region of charge/discharge depth is proposed. The hydrogen storage alloy satisfying the conditions has inferior service life properties in the case of being charged/discharged in the critical region of charge/discharge depth (H/M=about 0.1 to 0.8), but has excellent performance in initial activity and service life properties (cycle properties) in the case of being charged/discharged in the central region.
NAKAYAMA SHIGEKI
KAGEI SHINYA
INOUE HIDETOSHI
Michio Ichizawa