| 摘要 |
PROBLEM TO BE SOLVED: To provide a secondary battery in which the battery container is prevented from bulging and the generation of a crevice in an electrode group is prevented without interfering with cost reduction and causing a substantial increase in weight. SOLUTION: A lithium secondary battery comprises an electrode group (not shown) accommodated in a battery container 11. The battery container 11 consists of a plane surface part 11a and a half-cylindrical part 11b, and the thickness B of the plane surface part 11a is greater than the thickness C of the half cylindrical part 11b. By thickening the thickness of the plane surface part 11a, the overall strength of the battery container 11 is ensured and the weight of the battery container 11 is not increased substantially. Since the plane surface part 11a presses the flat part of the center part of the electrode group, the tension of the flat part becomes greater. Thereby the tension is uniformized in the curved surface on both sides of the electrode group and the flat part of the center part and the generation of a crevice in the electrode group is prevented without interfering with cost reduction. |
