NICKEL-HYDROGEN STORAGE BATTERY

PROBLEM TO BE SOLVED: To provide a nickel-hydrogen storage battery in which degradation of discharge capacity is low by suppressing elution of cobalt into an electrolytic solution and by suppressing elution of manganese into the electrolytic solution even if charge and discharge are repeated under high temperature atmosphere. SOLUTION: As for this nickel-hydrogen storage battery, either or both of W compound or Ta compound is added into the positive electrode active material which contains nickel hydroxide covered by Co compound as the main component in the positive electrode, and the negative electrode contains hydrogen storage alloy of CaCu5type expressed as MmNiaCobMncAld, and the sum of composition of Ni, Co, Mn, and Al (a+b+c+d) is 4.4 ≤ a+b+c+d ≤ 5.4, and composition of Mn (c) has a relationship of 0.05 ≤ c ≤ 0.2. By this, the elution of Co into the electrolytic solution is suppressed even if the charge and the discharge are repeated under the high temperatures, and collapse of electric conduction network can be prevented, thereby prevention of a situation becomes possible that the discharge capacity is degraded. COPYRIGHT: (C)2004,JPO