SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a secondary battery that can prevent malfunction of a current cut-off unit and can more surely and stably cut off a current route when the inner pressure of a battery container increases.SOLUTION: A secondary battery has a current cut-off unit 50 in a current route between an electrode in a battery container 10 and an external terminal 20A provided to the battery container 10. The current cut-off unit 50 has a diaphragm 5 which is disposed in the battery container 10 and connected to the external terminal 20A, and a power collection plate 30A connected to an electrode. The diaphragm 5 has a joint portion joined to the power collection plate 30A, and a thin wall portion provided on the periphery of the joint portion.