An audio output device is provided. The audio output device includes a battery, a wireless communication circuit, and a control circuit electrically connected to the battery and the wireless communication circuit, wherein the control circuit releases a communication connection with an electronic device using the wireless communication circuit if an electrical connection between the audio output device and a power supply device is sensed, starts charging of the battery of the audio output device by using the power supplied from the power supply device, temporarily activates the wireless communication circuit if either a residual battery quantity of the audio output device or a residual battery quantity of the power supply device satisfies a designated charging condition during charging of the battery of the audio output device, and transmits information about the charging state of the audio output device or the power supply device to the electronic device.

An electrical grid system includes: a first obtaining controller that obtains the electric power demand or supply request information from the electric power transmission and distribution facility; a second obtaining controller that obtains an electric storage state information; a third obtaining controller that obtains a vehicle information of an electric vehicle; a supply and demand satisfaction level calculation controller that calculates a supply and demand satisfaction level based on the electric power demand or supply request information; a selection controller that selects an electric vehicle to be guided to the charge or discharge spot based on the vehicle information obtained by the third obtaining controller and the supply and demand satisfaction level calculated by the supply and demand satisfaction level calculation controller; and a communication controller that sends a guide information to the selected electric vehicle.

A method includes receiving a wireless signal at an electronic device from an external electronic device. The method further includes determining whether the wireless signal indicates that power provided by the external electronic device to the electronic device satisfies a threshold. The method further includes, responsive to determining that the power provided by the external electronic device to the electronic device fails to satisfy the threshold, determining a state of the electronic device. The method further includes, responsive to determining the state of the electronic device, displaying a screen based on the state of the electronic device.

The embodiments of the present disclosure provide a multifunctional portable power bank and system. The multifunctional portable power bank includes a controller and an interface assembly connected to the controller. When detecting the access of an electronic device, the interface assembly outputs a driving voltage to the electronic device to drive the electronic device to communicate with the controller. The controller identifies the device type and operating voltage of the electronic device according to the content of the communication, and controls the interface assembly to supply power to the electronic device according to the operating voltage. The above-mentioned multifunctional portable power bank and system can supply power to electronic devices without charging function, are applicable to different types of electronic devices, and save the cost of configuring rechargeable batteries in electronic devices and the purchase cost of users.