Disclosed herein is a pouch-shaped secondary battery including a battery case, an electrode assembly having a structure in which a positive electrode and a negative electrode are stacked in the state in which a separator is interposed therebetween, an electrode lead having an asymmetrical notch formed in a first surface of the electrode lead, the electrode lead being electrically connected to electrode tabs of the electrode assembly, the asymmetrical notch being configured to induce the rupture of the electrode lead, a lead film attached to the first surface and a second surface of the electrode lead, the lead film adhering the electrode lead to the battery case, the lead film including a first lead film located between the electrode assembly and the asymmetrical notch, and a second lead film located between the asymmetrical notch and a portion of the electrode lead that protrudes out of the battery case.