| 摘要 |
A battery case (1, 8), substantially square in cross section, has four lateral walls (5, 6) each of which is gradually arc-shaped to expand outwardly with a radius of curvature R1. The cross section is adapted to satisfy equation R1/r=4 to 20, where r is the distance between a midpoint (C2) of each lateral wall (5, 6) and the center point (C1) in the cross section of the battery case (1, 8) and R1 is the radius of curvature. In addition, the battery case (8) is rounded at each corner with a radius of curvature of R2, and has a cross section that satisfies equation R2/r=0.3 to 0.8, where r is the distance between the midpoint (C2) of each lateral wall (6) and the center point (C1) in the cross section of the battery case (8) and R2 is the radius of curvature of each corner. |
