| 摘要 |
A nickel-metal hydride secondary cell holds therein an electrode group and an alkaline electrolyte solution containing NaOH as a main constituent of its solute. The electrode group has positive and negative electrodes lapped one over the other with a separator therebetween. The negative electrode contains a hydrogen absorbing alloy having a composition represented by the general formula: (RE1-xTx)1-yMgyNiz-aAla (where RE is at least one element selected from among Y, Sc and rare-earth elements, T is at least one element selected from among Zr, V and Ca, and subscripts x, y, z and a are values respectively satisfying 0@x, 0.05@y@0.35, 2.8@z@3.9, and 0.10@a@0.25), the hydrogen absorbing alloy has a crystal structure in which an AB2 subunit and an AB5 subunit are superimposed one upon the other, and Cr is substituted for part of the Ni. |
