US Patent 10027135 Apparatus for balancing battery power

An apparatus for balancing battery power can include: a battery selection circuit coupled to N batteries, where the battery selection circuit is configured to couple one of the N batteries to a charge and discharge port, where N is an integer greater than 1; a bi-directional power converter having a first terminal coupled to the charge and discharge port, and a second terminal coupled to a storage capacitor; N detection circuits corresponding to the N batteries, where each of the N detection circuits is configured to detect a state of a corresponding of the N batteries; and a control circuit configured to control the battery selection circuit to couple a selected battery to the charge and discharge port, and to charge or discharge the selected battery through the bi-directional power converter to maintain a voltage of the storage capacitor to be within a predetermined range.