| 摘要 |
PURPOSE:To reduce evolution of hydrogen gas, prevent electrolyte leakage, increase of internal impedance, rupture, and increase a battery life and manufacturing efficiency by cleaning the surface of copper or copper alloy, which is to be in contact with a negative active mass, of a negative current collector with a chemical polishing solution f hydrogen peroxide and sulfuric acid family containing a mercury ion and a rust preventive of copper or copper alloy, and applying amalgamation and rust preventing treatment at the same time. CONSTITUTION:A reverse curl portion 5 of the circumference of a negative case 4 is covered with a synthetic resin 6. This case is treated with a chemical polishing solution that the molar ratio of sulfuric acid to hydrogen peroxide is 0.045 and about 0.1mg of mercury ion per negative case and about 0.2% of benzotriazole as a rust preventive are contained for about 2min at room temperature. Then the case is washed with water, washed with a solution containing sulfuric acid, washed with water, neutralized, and washed with water again. By this treatment, the exposed surface of copper is polished chemically and harmful foreign matter is removed, and at the same time amalgamation and rust preventing treatment are applied on the cleaned surface. |
