HYDROGEN STORAGE ALLOY POWDER FOR SECONDARY BATTERY, AND ITS DETERIORATION RATE DETERMINING METHOD

摘要

PROBLEM TO BE SOLVED: To confirm a component segregation degree of Mn by a segregation residual index to determine a quality property as a battery for practical use. SOLUTION: In this hydrogen storage alloy powder and this deterioration rate determining method, a misch metal nickel hydrogen storage allow (AB5 type) containing Mn is pulverized by a gas atomizing method, then the maximum concentration difference in EPMA ray analysis of heat-treated Mn powder is compared with the maximum concentration difference in the EPMA ray analysis of the Mn powder before heat-treatment, and a ratio (= segregation residual index) thereof is made to be 0.3 or less compared with that before the heat treatment.