PRODUCTION OF POWDERY HYDROGEN OCCLUDING ALLOY FOR NEGATIVE ELECTRODE OF NICKEL-HYDROGEN SECONDARY BATTERY AND PRODUCTION OF NEGATIVE ELECTRODE FOR NICKEL-HYDROGEN SECONDARY BATTERY

摘要

PURPOSE:To produce a powdery hydrogen occluding alloy for the negative electrode of a nickel-hydrogen secondary battery suppressing the rise of the internal pressure of the battery at the time of overcharge by heat-treating a powdery hydrogen occluding Mm-Ni alloy contg. Co at a specified temp. for a specified time in an atmosphere having a specified concn. of oxygen. CONSTITUTION:A powdery hydrogen occluding Mm-Ni alloy contg. Co in about >=0.5 ratio to Mm (misch metal) is heat-treated at 100-250 deg.C for 10-60min in an atmosphere contg. 0.1-10vol.% oxygen to form cobalt oxide on the surface of the alloy. When the resulting powdery hydrogen occluding alloy is used as the constituent material of a negative electrode, the rise of the internal pressure of a battery using the electrode can be controlled to a level of about 15kgf/cm<2>.