| abstract |
A nickel hydrogen secondary battery 2 has an electrode group 22 including a separator 28 , a positive electrode 24 , and a negative electrode 26 . The negative electrode 26 has a negative electrode core, and a negative electrode mixture held on the negative electrode core. The negative electrode mixture contains a hydrogen absorbing alloy and a water repellent. The hydrogen absorbing alloy has a composition represented by the general formula: Ln 1-x Mg x Ni y-a-b Al a M b , where Ln represents at least one element selected from rare earth elements, Ti and Zr; M represents at least one element selected from V, Nb, Ta, and the like, and the subscripts a, b, x and y satisfy relations represented by 0.05≤a≤0.30, 0≤b≤0.50, 0≤x<0.05 and 2.8≤y≤3.9, respectively. The hydrogen absorbing alloy has a structure of an A 2 B 7 type. The water repellent comprises a perfluoroalkoxyalkane. |