A power bank apparatus includes a power storage unit, a first power output port and a first power input port. The power storage unit is connected to the first power input and output ports. The power bank apparatus is connected to a controller through the first power output port. The controller includes a control unit, a second power input port and a second power output port. The control unit is connected to the second power input and output ports, and the second power input port is connected to the first power output port, and the control unit is provided for controlling an output voltage value of the second power output port.