| 摘要 |
PROBLEM TO BE SOLVED: To provide a control valve-type lead storage battery which is improved in life characteristic, and arranged so as to prevent a welding part of a negative electrode plate ear part and a negative electrode strap from being broken.SOLUTION: In a control valve-type lead storage battery, the alloy composition of a negative electrode ear part, and the alloy composition of a negative electrode strap are made a Pb-Ca-Sn based alloy including 0.07-0.12 mass% of Ca and 0.10-0.75 mass% of Sn to the total mass of the alloy, and the density of the negative electrode material after chemical conversion is 2.9-3.9 g/cm. The further reduction in size of crystal grains restrains the breaking of a welding part owing to grain boundary corrosion. In addition, the reaction area of oxygen absorption of a negative electrode plate is ensured by making the density of the negative electrode material after chemical conversion an appropriate one, and an amount of oxygen near the ear part and strap part is reduced. As a result, the grain boundary corrosion is suppressed further.SELECTED DRAWING: Figure 6 |
