A battery module includes a pair of battery cells, each battery cell having an electrode lead, and the battery cells being stacked to face each other; a connector configured to connect the electrode leads of battery cells; and a connector breaking device disposed in a space formed between terrace portions of the battery cells and configured to be operated with a pressure applied to the connector breaking device due to swelling of at least one of the battery cells to cut off an electric connection between the connector and the electrode leads is provided. A method to interrupt an electrical connection in a battery module is also provided.