Hydrogen-absorbing alloy for alkaline storage battery, and alkaline storage battery

Abstract

A hydrogen-absorbing alloy for alkaline storage battery which is produced by a rapid cool using a rapid quenching method and whose component is represented by a general formula Ln 1-x Mg x Ni a-b-c Al b Z c is used for a negative electrode of an alkaline storage battery.

1 . A hydrogen-absorbing alloy for alkaline storage battery which is produced by a rapid cool using a rapid quenching method having a composition represented by a general formula Ln 1-x Mg x Ni a-b-c Al b Z c  where Ln is at least an element selected from rare earth elements including Y, Zr, and Z is at least one element selected from the group consisting of V, Nb, Ta, Cr, Mo, Mn, Fe, Co, Ga, Zn, Sn, In, Cu, Si, P, and B, 0.05≦x<0.25, 2.8≦a≦3.9, 0<b≦0.30, and 0≦c≦0.25. 
     
     
         2 . The hydrogen-absorbing alloy for alkaline storage battery according to  claim 1 , wherein x in the above formula satisfies 0.05≦x≦0.20. 
     
     
         3 . The hydrogen-absorbing alloy for alkaline storage battery according to  claim 1 , wherein (x+b), a total amount of x and b in the above formula is not less than 0.30. 
     
     
         4 . The hydrogen-absorbing alloy for alkaline storage battery according to  claim 2 , wherein (x+b), a total amount of x and b in the above formula is not less than 0.30. 
     
     
         5 . The hydrogen-absorbing alloy for alkaline storage battery according to  claim 1  subjected to a heat treatment at a temperature which is 25° C. to 70° C. lower than a liquefy beginning temperature Tm, after being rapidly cooled by the rapid quenching method. 
     
     
         6 . The hydrogen-absorbing alloy for alkaline storage battery according to  claim 2  subjected to a heat treatment at a temperature which is 25° C. to 70° C. lower than a liquefy beginning temperature Tm, after being rapidly cooled by the rapid quenching method. 
     
     
         7 . The hydrogen-absorbing alloy for alkaline storage battery according to  claim 3  subjected to a heat treatment at a temperature which is 25° C. to 70° C. lower than a liquefy beginning temperature Tm, after being rapidly cooled by the rapid quenching method. 
     
     
         8 . An alkaline storage battery comprising: a positive electrode; a negative electrode using a hydrogen-absorbing alloy; and an alkaline electrolyte, characterized in that the negative electrode uses the hydrogen-absorbing alloy for alkaline storage battery according to  claim 1 .