| 摘要 |
PROBLEM TO BE SOLVED: To heighten the electroconductivity of an active material and maintain the rate of utilization of active material at a high level for a long period of time by specifying the composition of a Pb-Sn-Sb alloy powder to be used as active material. SOLUTION: An alloy to be used as active material contains 0.01-0.1wt.% Sn of Pb content and also Sb in an amount 1-50wt.% of the Sn content. In this composition, the alloy takes an approx. perfect solid solution state, and if this is used as an active material, the electroconductivity can be heightened and the rate of utilization of the material be maintained at a high level for a long period. The reason therefore is; the active material layer takes such a condition that electrocoductive SnO2 and tri-valent or penta-valent ions are mixed together uniformly in particles of PbO2 and PbSO4 of the positive electrode active material, and therefore, SnO2 is not be easily eluted into the electrolytic solution even through repetition of the charging/discharging cycle, and the rate of utilization of the active material can be maintained high for a long period. The Sb included in SnO2 works to heighten the electroconductivity. |
