| 摘要 |
PROBLEM TO BE SOLVED: To provide a battery having an excellent charge and discharge cycle characteristic by setting the active material filling density of at least one of a strip positive electrode and a strip negative electrode at a central part in the cross direction thereof lower than the active material filling density at other parts. SOLUTION: In this lithium secondary battery, the active material filling density at a central part in the cross direction is desirably set lower at 5-10% than the active material filling density at other parts, and an area of the central part in the cross direction is set at 10-20% of the area of the strip electrode. The active material filling density at a central part C in the cross direction of at least one strip electrode E of a strip positive electrode and a strip negative electrode is set lower than the active material filling density of other parts D1, D2. Since the rate of the quantity of the electrolyte in relation to the quantity of the active material at the central part C in the cross direction is larger in comparison with a conventional battery, excessive charge and excessive discharge is hard to be generated at the central part C in the cross direction of the strip electrode E, and decomposition of the electrolyte and deterioration of the active material are hard to be generated at the central part C in the cross direction in a charge and discharge cycle. |
