Secondary cell safety device including pressure release mechanism and current cutoff mechanism

A secondary cell comprising:

• a cell case having a first opening and containing an internal electrode;
• and
• a safety device mounted on the cell case, the safety device including:
• a lid positioned over the first opening of the cell case and defining a second opening;
• an external electrode mounted on the lid;
• a diaphragm mounted on the lid and covering the second opening;
• an actuator mounted on the diaphragm;
• an elongated member supported on the lid and positioned adjacent to the actuator such that the actuator is positioned between the elongated member and the diaphragm, the elongated member having a conductive path formed thereon, the conductive path including a first end connected to the internal electrode of the secondary cell and a second end connected to an external electrode;
• wherein when an internal pressure of the cell case interior increases to a first pressure, the diaphragm is deformed toward the elongated member by the internal pressure, thereby biasing the actuator against the elongated member and causing the elongated member to deform, wherein deformation of the elongated member breaks the conductive path such that current between the external electrode and the internal electrode along the conductive path is cut off.

A secondary cell comprising:

• a cell case having a first opening and containing an internal electrode;
• and
• a safety device mounted on the cell case, the safety device including:
• a lid positioned over the first opening of the cell case and defining a second opening;
• an external electrode mounted on the lid;
• a pressure receiving member mounted on the lid and covering the second opening;
• and
• a fastening member mounted on the lid and including a plurality of pawls extending over the pressure receiving member, whereby the pressure receiving member is fastened over the second opening to seal an interior of the cell case;
• wherein when the internal pressure of the cell case increases to a first pressure, the pressure receiving member pushes against the pawls of the fastening member, whereby the pawls are bent to allow movement of the pressure receiving assembly relative to the lid, thereby forming a gap between the pressure receiving assembly and the lid which allows gas to escape from the cell case interior.