Patent attributes
A power bank has a station and a plurality of battery modules. When the battery modules are stacked on the station, rechargeable batteries of the battery modules are electrically connected in parallel. When a charging port of the station is electrically connected to an external power supply, a charging-discharging control circuit of the station receives electric energy from the external power supply via the charging port and uses the received electric energy to charge the rechargeable batteries. When a discharging port of the station is electrically connected to an external electronic device, the charging-discharging control circuit transfers electric energy received from the rechargeable batteries to the external electronic device. Each of the battery modules is replaceable, and the total number of the battery modules of the power bank is adjustable.