CURRENT BREAKER, SAFETY CIRCUIT AND SECONDARY BATTERY PACK

A current cut-off device includes a plate-shaped terminal piece having a contact , a movable piece including an elastic portion formed in a plate shape so as to be elastically deformed and a movable contact arranged at one end portion of the elastic portion and having the movable contact so as to be pressed against and in contact with the contact , and a thermally actuated element which biases the movable piece by deforming in accordance with a temperature change and causes a state of the movable piece to be shifted from a conductive state in which the movable contact is in contact with the contact to a cut-off state in which the movable contact is separated from the contact . When the state of the movable piece is shifted from the conductive state to the cut-off state, as the movable contact moves, it gets over the contact