The present invention provides a secondary battery comprising a battery
package which encloses the outer perimeter of the secondary battery and covers the entire outer surface of positive and negative electrodes and a portion of each terminal of the positive and negative electrodes, wherein the battery
package is formed of a laminate film comprising an outer
polymer layer, an inner aluminum layer and an
adhesive layer formed on a portion of the inner surface of the aluminum layer, the aluminum layer of the battery
package being electrically connected with either of the positive and negative terminals. In another aspect, the invention provides a secondary battery comprising a battery package which encloses the outer perimeter of the secondary battery and covers the entire outer surface of positive and negative electrodes and a portion of each terminal of the positive and negative electrodes, wherein the battery package is formed of a laminate film comprising an outer
polymer layer, an inner aluminum layer and an
adhesive layer formed on a portion of the inner surface of the aluminum layer, and further comprises at least one
electrically conductive metal foil on at least one of the outer upper and lower surfaces thereof, and each of the
electrically conductive metal foil is electrically connected with either of the positive and negative terminals. In the inventive secondary battery, current occurring in conditions such as
nail penetration can flow to either the aluminum layer of the package or the
metal foil outside the package so as to inhibit
heat generation inside the battery, thus improving the safety of the battery.