This invention provides an electronic device that has a battery with a power storage unit and a display module, a power detector and a display control module. The power storage unit is for storing electrical power and the display module is placed on the surface of the battery. The power detector is selectively coupled to the battery, and generates a remaining power signal after detecting the remaining power in the battery. The remaining power signal is used to control the display control module. When the power detector is selectively coupled to the battery, the display module shows the current remaining power in response to the action of the display control module. When the power detector is separated from the battery, the display module is essentially capable of maintaining the showing of remaining power.