A pouched lithium secondary battery including a battery unit having a positive electrode plate, a negative electrode plate, and a separator disposed between the positive electrode plate and the negative electrode plate; a positive electrode tab electrically connected with the positive electrode plate; a negative electrode tab electrically connected with the negative electrode plate; a case havinga space to accommodate the battery unit, and a sealing edge around the space; and a positive electrode voltage applying unit to apply a positive electrode voltage to both the positive electrode tab and the case. The case may comprise an intermediate layer comprising a metal thin film; and internal and external layers coated on opposite surfaces of the intermediate layer, respectively. The positive electrode voltage applying unit may be formed by exposing a portion of the intermediate layer and electrically connecting the exposed portion of the intermediate layer and the positive electrode tab.