| 摘要 |
A prismatic can type lithium ion rechargeable battery includes an electrode assembly (12), a prismatic can (10) accommodating the electrode assembly, a cap assembly (20) including a cap plate (40) closing an upper opening portion of the prismatic can. A distortion prevention portion (150, 155, 180, 280, 380, 480) is formed on the maximum area surface of the prismatic can. A safety vent is formed on the maximum area surface of the prismatic can, and includes a weakened portion (160, 165, 175, 260, 360, 460). The weakened portion is formed outside a periphery of the distortion prevention portion. Accordingly, if can distortion of the prismatic battery is caused by the internal pressure, force acting on the safety vent is concentrated on the weakened portion, breaking the weakened portion. This prevents the battery from exploding or catching fire, and so improves safety and reliability of the battery. |
