| 摘要 |
The purpose of the present invention is to obtain a secondary battery in which the insulation property between an electrode group and a battery container against an external force can be improved without lowering the battery capacity. The secondary battery (1) of the present invention has : a wound electrode group (40) formed by winding electrodes (41, 42) in which mixture layers (41b, 42b) are formed on metal foils (41a, 42a); a battery container (4) for housing the wound electrode group (40) ; and an insulator (5) interposed between the wound electrode group (40) and the battery container (4) . The insulator (5) has a section interposed between the battery container (4) and a mixture layer laminated region (40d) formed at the center of the wound electrode group (40) in the winding axis direction, and a section interposed between the battery container (4) and a pair of metal foil exposed portions (41c, 42c) formed on both sides of the wound electrode group (40) in the winding axis direction, wherein the latter region is thicker than the former region. |
