Disclosed herein is a pouch-shaped secondary battery including a pouch-shaped battery case surrounding an electrode assembly, a first electrode lead connected to the electrode assembly and extending to a joint of the battery case, a second electrode lead detachably connected to the first electrode lead and extending out of the battery case, a connection layer coupling the first electrode lead and the second electrode lead to each other, and a sealing layer coupling the battery case to the first electrode lead and the second electrode lead, wherein the first and second electrode leads are configured to be detached from one another in order to secure the safety of a pouch-shaped battery cell when the pouch-shaped battery cell swells due to gas generated in the pouch-shaped battery cell while the pouch-shaped battery cell is in an abnormal state or when the pouch-shaped battery cell is overcharged.