| 摘要 |
PURPOSE:To improve the slow discharge cycle life of a lead acid battery without deteriorating the rapid discharge characteristic of the battery, by forming a film made of a water-soluble high molecular compound over the entire surface of a positive plate made of an expanded metal grid. CONSTITUTION:A lead-calcium-tin alloy is rolled and expanded into a netlike expanded metal grid, which is packed with a pasty active material prepared by kneading lead powder with a dilute sulfuric acid. As for a positive plate, the plate is either immersed in an aqueous solution of a sodium salt of carboxymethylcellulose or polyvinyl alcohol so as to make the solution to adhere to the entire surface of the plate, or coated with the solution by means of a spray or a brush. After that, the plate is dried, thereby making the plate to be coated with a water-soluble high molecular resin film. |
