An electronic device is provided. The electronic device includes a main system processing a process, a power control unit and a battery module. The power control unit provides operating power to the main system via an external power source when the external power source has been connected, and detects whether the power control unit has received a battery protection signal. The battery module discharges with a self-discharge rate when the battery module has received the protection signal from the power control unit. When the power control unit has not received the battery protection signal, the power control unit provides a charging power to the battery module via the external power source. When the power control unit has received the battery protection signal, the power control unit does not provide the charging power to the battery module, and transmits the protection signal to the battery module.