| 摘要 |
PURPOSE:To prevent the rupture of a battery caused by increase in inner pressure by bending inward the opening edge of an outer jacket so that the bending diameter of a battery case in a unit cell sealing part is smaller than that of a metal outer jacket. CONSTITUTION:A PTC element is pressed against the outer bottom 1a of a battery case 1 constituting a unit cell. An insulating jacket 5 is placed inside an outer jacket 4, and an opening edge 4a of the outer jacket 4 is bent inward to seal a battery, and to press the PTC element against the outer bottom 1a of the battery case 1. When the bending diameter of the battery case 1 of the unit cell A is phi1 and the bending diameter of the opening edge 4a of the outer jacket 4 is phi2, the battery is sealed so as to satisfy the relation of phi1<phi2. By specifying the bending diameter, even if the inner pressure of the battery increased, the inner pressure increase can be stopped at a low level without the damage of soft bending function of sealing part. |
