| 摘要 |
PURPOSE:To improve the self-discharge property and filling rate of a battery by using carbonaceous material for which particles of dia. 5mum or smaller are 5% or less in volume percentage and the average dia. of particles is within 25-100mum. CONSTITUTION:A negative plate 2, a separator 3a, a positive plate 1, and a separator 3b are laminated in sequence, wound in a spiral form and housed in a can 4. In this case, for carbonaceous material used as the active material for a negative electrode of the negative plate 2, particles of dia. 5mum or smaller are 5% or less, preferably 3% or less, in volume percentage of total carbonaceous material and the average dia. of particles is 25-100mum, preferably within 30-50mum. In this way, the carbonaceous material for which particles of dia. 5mum or smaller are 5% or less in volume percentage and the average dia. of particles is 25mum or larger eliminates an unnecessarily large specific surface area and restrains self-discharge. Also, when the average dia. of particles is 100mum or smaller, the carbonaceous material is not lowered in filling rate. It is thus possible to improve self-discharge property and filling rate. |
