Hydrogen-absorbing alloy for battery, method of manufacturing the same, and secondary nickel-metal hydride battery

A method of manufacturing a hydrogen-absorbing alloy for a battery, comprising the step of:

• injecting a molten alloy having the composition represented by a general formula A Ni.sub.a Mn.sub.b M.sub.c where A is at least one element selected from the group consisting of rare earth elements including Y (yttrium), M is a metal mainly composed of at least one element selected from the group consisting of Co, Al, Fe, Si, Cr, Cu, Ti, Zr, Zn, Hf, V, Nb, Ta, Mo, W, Ag, Pd, B, Ga, In, Ge and Sn, 3.5.ltoreq.a.ltoreq.5, 0.1.ltoreq.b.ltoreq.1, 0.ltoreq.c.ltoreq.1, 4.5.ltoreq.a+b+c.ltoreq.6 onto the traveling surface of a cooling roll(s) rotating at a high speed;
• and
• rapidly quenching and solidifying said molten alloy at a quenching rate of 1800.degree. C./sec. or higher to prepare a rapidly-quenched molten alloy to provide said hydrogen-absorbing alloy for a battery, wherein said hydrogen-absorbing alloy has columnar structures in which an area ratio of the columnar structures having the ratio of a width to a length (aspect ratio) of 1:2 or higher is 50% or more, and said columnar structures have an average width of 30 microns or less.