| 摘要 |
PURPOSE:To improve the charge-and-discharge efficiency of a sodium-sulfur battery by using a positive electrode consisting of fiber layers impregnated with sulfur the fiber densities of which increase as they become more apart from the solid electrolyte. CONSTITUTION:A sack-like solid electrolyte tube 1 made of beta-alumina and a positive electrode 11 prepared by impregnating conductive heat-resistant graphite fiber with sulfur, are installed in a positive case 2. The positive electrode 11 consists of the first, the second and the third layers 12, 13 and 14 which are closer to the solid electrolyte tube 1 in that order. The fiber densities of the layers 12, 13 and 14 increase in that order. A sodium-sulfur battery is constituted by combining the thus formed positive body with a negative case 3 packed with sodium 5 used as a negative active material. Because of the above structure, a circulating flow of the active material occurs in the positive electrode 11, thereby actively supplying the active material to inside the reaction area and actively transferring the active material to outside the reaction area. Consequently, it is possible to improve the charge-and-discharge efficiency of the battery and to increase its charge-and-discharge capacity. |
