Disclosed herein is a high-power, large-capacity battery module including a plurality of battery cells or unit modules connected in series to each other such that the battery cells or the unit modules are stacked while being in tight contact with each other or being adjacent to each other, wherein the battery module is fixed such that the stacked state of the battery cells or the unit modules is maintained even when the volume of the battery cells or the unit modules changes at the time of charging and discharging the battery cells or the unit modules, and a portion of an electrode terminal connection region between the battery cells or between the unit modules is weak with respect to the volume expansion of the battery cells or the unit modules such that an expansion stress caused by the swelling of the battery cells is concentrated on the electrode terminal connection region, whereby the electrode terminal connection region is broken, and therefore, an electrical cut-off occurs at the electrode terminal connection region, when the swelling exceeds a predetermined value.