SECONDARY BATTERY

摘要

PURPOSE: A secondary battery is provided to prevent the explosion and firing by emitting the gas and pressure generated from the inside of an external case and to improve the lifespan. CONSTITUTION: A secondary battery comprises: an electrode assembly; an external case(200) housing the electrode assembly; an electrode terminal(300) which is electrically connected to the electrode assembly and is arranged in the external case in order to be exposed to the outside of the external case; a vent hole penetrated to the electrode terminal; and a valve unit(500) which is arranged in the electrode terminal and opens and closes the vent hole according to the change of the inner pressure of the case.