A battery pack is configured to supply electric power to an electric work machine, such as a power tool or outdoor power equipment. The battery pack includes a first battery-signal terminal and a second battery-signal terminal. The first battery-signal terminal outputs, to the electric work machine, a first signal indicating that discharging is to be prohibited or permitted. The second battery-signal terminal outputs, to the electric work machine, a second signal indicating that discharging is to be prohibited or permitted. Thus, two communication paths are provided for transmitting signals to permit or prohibit discharging of the battery pack.