Patent ID: 8877370

Claim:
A battery having a can containing an electrode assembly and an electrolyte and a cap assembly with a cap plate having an electrolyte injection unit, said electrolyte injection unit having an injection hole via which said electrolyte is injected into the electrode assembly and a sealing member to seal said injection hole, the cap plate is coupled to the can and an upper cover is coupled to the cap plate, comprising: a gas sensor located within the cap assembly and positioned immediately adjacent to said sealing member of said electrolyte injection unit to detect leakage of the electrolyte into the cap assembly; and a protective circuit module mounted to the cap plate and electrically coupled to the gas sensor, the protective circuit module is adapted to stop a charge/discharge operation of the battery and discharge the battery upon receipt of a signal from the gas sensor indicating detection of leakage of the electrolyte into the cap assembly.