HYDROGEN STORAGE ALLOY POWDER EXCELLENT IN CHARGING AND DISCHARGING CHARACTERISTICS

摘要

PROBLEM TO BE SOLVED: To provide hydrogen storage alloy powder excellent in charging and discharging characteristics and mainly used for a Ni-hydrogen secondary battery. SOLUTION: In this hydrogen storage alloy powder excellent in charging and discharging characteristics, the surface layer part enriched in Ni and Co as the main phases has a thickness of 10 to 500 nm, and also, the ratio (tmax/tmin) of the maximum part (tmax) to the minimum part (tmin) in the film thickness of the surface layer is controlled to 1 to 10.