| 摘要 |
PURPOSE:To increase the porosity of a negative active material, and enhance the utilization rate of the active material by adding heat-expanded capsules containing a low-boiling-point hydrocarbon to make a negative paste. CONSTITUTION:After lead oxide powder is combined with both a negative expander and heat-expanded micro-capsules containing a low-boiling-point hydrocarbon, the mixture is subjected to sufficient dry mixing, then kneaded after water or dilute sulfuric acid is added, thereby preparing a negative paste. The thus prepared paste, after being packed into a grid, is heated to cause the microcapsules to bubble so that a given bubbling expansion coefficient is achieved, the heated so as to diffuse the low-boiling-point hydrocarbon contained in the capsules completely outside them an to decompose the shell walls of the capsules, thereby manufacturing a negative plate in which many fine holes are formed in its active material. By arbitrarily selecting the grain diameter of the microcapsules which have not bubbled, the amount of the capsules added and heating temperature which determines the bubbling expansion coefficient, the distribution of the fine holes of the active material as well as the porosity of the active material can be easily varied. |
