BATTERY DEVICE, BATTERY MANAGEMENT DEVICE, ELECTRONIC DEVICE, ELECTRIC MOTOR VEHICLE, POWER STORAGE DEVICE, AND POWER SYSTEM

A battery device includes a battery unit which has a plurality of batteries connected in series; first and second lines each led from a cathode and an anode of the battery unit; first and second semiconductor switch elements which are inserted into the first line; a driver configured to generate a drive signal to turn off one of the first and second semiconductor switch elements when a protective operation is performed; a third semiconductor switch element which is inserted between a gate of at least one of the first and second semiconductor switch elements and an intermediate voltage point of the battery unit; and a semiconductor switch controller including a detector configured to turn on the third semiconductor switch element when the drive signal is detected and to apply a potential smaller than a source potential to a gate of one of the first and second semiconductor switch elements from the intermediate voltage point via the third semiconductor switch element.