| 摘要 |
PROBLEM TO BE SOLVED: To reduce costs, improve charge accepting properties, and prevent their deterioration with the lapse of time, by providing a charge-acceptance improving layer on an outer surface of a solid electrolyte tube, and using, as the charge-acceptance improving layer, a fiber-stack layer made up of a fibrous substance. SOLUTION: Aβ"-alumina tube is used as a material of a solid electrolyte tube, and alumina fiber having an average fiber size of 3μm and an average fiber length of 100μm is spread by 500μm over an outer surface of theβ"-alumina tube with silica sol used as an adhesive and then baked at 500 deg.C in the air for 5 hours, thereby forming a charge-acceptance improving layer. That is, the charge-acceptance improving layer is formed by stacking the insulating fiber on the outer surface of the solid electrolyte tube by the use of the adhesive. Deterioration due to a number of cycles, in the depth of discharge of a battery achieved at the time of completion of charging, is very little and is on the order of 12% even after 2000 cycles, if a discharge cease voltage is as low as 1 V. If the discharge cease voltage is as high as 1.8 V, the deterioration hardly occurs and it is about 10% in the event of 200 cycles.
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