| 摘要 |
PROBLEM TO BE SOLVED: To provide a secondary battery for which the degradation of charge-discharge capacity and a load characteristic is restrained, even if charging and discharging are repeated by using sodium polyacrylate as a thickener of negative electrode paste, and a sodium salt of β-naphthalenesulfonic acid formalin condensate as a dispersant. SOLUTION: Preferably, the ratio of an addition quantity of a dispersant to the total quantity of a thickener is 0.01-5 wt.%. An electrode group comprises a positive electrode plate 5, a negative electrode plate 6, a separator 7, a positive electrode lead 3, negative electrode lead 7 and the like, they are overlaid, rolled and then received in a case 8. A paste for the negative electrode is provided by mixing and dispersing 50 pts.wt. of scale-like graphite powder, 5 pts.wt. of styrene-butadiene rubber as a binder, 1 pts.wt. of sodium polyacrylate as a thickener, and 23 pts.wt. of an aqueous solution, wherein 1 pts.wt. of mixed powder prepared by adding 1 pts.wt. of a sodium salt of β-naphthalenesulfonic formalin condensate as a dispersant in sodium polyacrylate is dissolved in 99 pts.wt. of water, the paste is applied to a negative electrode collector formed of copper foil, the collector is dried, and cut to provide a negative electrode plate. |
