A battery management device includes a detection circuit, a charge control circuit, and a discharge control circuit. The detection circuit is configured to output a first control signal and a second control signal according to a volume of a rechargeable battery. The charge control circuit is electrically coupled to the rechargeable battery and the detection circuit, and configured to open a charge loop of the rechargeable battery according to the first control signal. The discharge control circuit is electrically coupled to the rechargeable battery and the detection circuit, and configured to close a discharge path of the rechargeable battery according to the second control signal.