SECONDARY BATTERY HAVING VENT PORTION FORMED ON INSULATION FILM AND METHOD FOR MANUFACTURING THE SAME

Provided is a secondary battery which includes an electrode assembly including a positive electrode, a negative electrode and a separator interposed between the positive electrode and the negative electrode, and received in a battery casing together with an electrolyte, wherein the positive electrode includes a positive electrode tab, and the negative electrode includes a negative electrode tab, the positive electrode tab is connected electrically to a positive electrode lead, the negative electrode tab is connected electrically to a negative electrode lead, and the positive electrode lead and the negative electrode lead are exposed to the outside through a sealing portion of the battery casing, each of a positive electrode insulation film and a negative electrode insulation film is attached to a portion where each of the positive electrode lead and the negative electrode lead is in contact with the sealing portion of the battery casing, and at least one insulation film of the positive electrode insulation film and the negative electrode insulation film has a vent portion surface-treated with a non-adhesive material between the insulation film and the positive electrode lead or the negative electrode lead, at the portion where the positive electrode lead or the negative electrode lead is attached.