HYDROGEN OCCLUSION ALLOY POWDER, ITS PRODUCTION AND ELECTRODE CONSISTING THEREOF

摘要

PROBLEM TO BE SOLVED: To obtain hydrogen occlusion alloy powder which has an excellent discharge capacity and charge and discharge repetition life when the power is used for the battery by specifying the ratio of the average grain size of the alloy powder pulverized after a heat treatment to the average grain size of the substantially spherical hydrogen occlusion alloy powder before the heat treatment. SOLUTION: The hydrogen occlusion alloy powder at least partially sintered during the heat treatment is pulverized and the sintered compacts are nearly completely disintegrated. The disintegration is so executed that the ratio of the average grain size of the pulverized powder after the heat treatment to the average grain size of the powder before the heat treatment attains a range of 0.85 to 1.15. Namely, the powder having nearly the same average grain size as the average grain size of the powder before the heat treatment is obtd. Such pulverization is easily attained by using a pulverizing machine of which the main pulverizing mechanism is impact. The hydrogen occlusion alloy powder having the spherical shape can thus be obtd. Consequently, a high-density electrode packed with a large amt. of the hydrogen occlusion alloy by the peculiar high packing property of the spherical powder is obtd. and the capacity of the battery is made higher.