BATTERY DEVICE AND VEHICLE

A device according to an embodiment includes at least one assembled battery; first switches that switch an electrical connection state of main circuits connected between the assembled battery and the load; second switches that switch an electrical connection state of second main circuits branched from the main circuits and are connected between the assembled battery and the load; a BMU that controls operations of the first switches based on an operation command supplied from the load; and a power supply circuit that supplies power to the BMU and second switches when a start command supplied from the outside is ON.