Rechargeable battery comprising short circuit unit responsive to pressure and module thereof

A rechargeable battery module comprising:

• a plurality of unit cells adjacent one another;
• and
• at least one bus bar connecting unit cells of the plurality of unit cells to each other in series,
• wherein a unit cell of the plurality of unit cells comprises:
• a case containing an electrode assembly;
• a cap plate coupled to the case and sealing an opening of the case;
• a first electrode terminal connected to a first electrode of the electrode assembly and electrically connected to the case;
• a second electrode terminal connected to a second electrode of the electrode assembly and electrically insulated from the case when a pressure inside the case is less than a threshold pressure;
• and
• a short-circuit unit comprising a short-circuit member connected to the second electrode terminal, the short-circuit unit adapted to short-circuit the second electrode terminal to the case by swelling a portion of the case to contact and electrically connect to the short-circuit member when the pressure inside the case is equal to or greater than the threshold pressure,
• wherein the short-circuit unit comprises a swelling induction unit comprising the portion of the case, the portion of the case having a thickness that is less than a thickness of another portion of the case surrounding the portion, and wherein the short-circuit member faces and is contactable with an outer surface of the portion of the case.