Sealed battery with internal pressure activated safety mechanism

A sealed battery comprising:

• a can for receiving an electric generator, the can having an opened top end;
• a deformable plate air tightly mounted on the opened top end with a gasket disposed between the deformable plate and an inner wall of the opened top end;
• a terminal cap disposed on top of the deformable plate, the terminal cap being elevated except for an edge;
• and
• a circuit breaker disposed between the deformable plate and the terminal cap to cut-off current flow when the deformable plate is deformed by internal pressure increased above an allowable level;
• wherein the circuit breaker comprises:
• an insulating plate having a bridge disposed traversing the deformable plate and provided with a mechanically weak portion and a via hole, the mechanically weak portion being severed when the deformable plate is deformed by internal pressure increased from a predetermined level;
• an upper conductive layer formed on an upper surface of the insulating surface;
• a terminal member disposed through the via hole to electrically connect the upper conductive layer to the deformable plate;
• and
• a lower conductive layer formed on a lower surface of the insulating plate, the terminal member being connected to the deformable plate through the lower conductive layer.