A method of charging a battery, wherein the battery comprises a plurality of battery cells, includes charging the battery with a first voltage for a first time period, which charging is first charging, charging the battery with a second voltage for a second time period, which charging is second charging, and charging the battery with a third voltage for a third time period, which charging is third charging, wherein lengths of the first to third time periods are determined in correspondence with a magnitude of charging current of the battery.