Hydrogen storage alloy powder and hydrogen storage electrode for Ni-H secondary battery

摘要

PROBLEM TO BE SOLVED: To increase capacity, stabilize product quality, and prevent increase in production cost by using globular hydrogen absorbing alloy powder capable of densely filling. SOLUTION: Hydrogen absorbing alloy powder having a practically globular shape, a mean particle diameter of 5m or more but less than 50m, in which the ratio of the powder having a mean particle diameter in the particle size distribution of 30m or more is 5% or more but less than 30%, and that of 20m or less is 5% or more is used. The globular powder having such mean particle diameter and such particle size distribution has high tap density (the index of the maximum filling density of powder), is filled densely, difficult to slide in rolling in a production process, and smoothly rolled like crushed powder having irregular shapes. An electrode holding high filling density after rolling, having uniform filling ratio and thickness is obtained, capacity is increased, product quality is stabilized, and product yield is enhanced.