a state-of-charge (SOC) measurer configured to measure a SOC of a battery; and

a charge controller configured to control a charging speed of the battery in response to the SOC of the battery being included in a preset SOC section,

wherein the preset SOC section has a change in resistance or a change in potential due to ions inserted into a material constituting the battery equal to or greater than a reference value,

wherein the charge controller controls a charging speed of the battery before and after the preset SOC section to be higher than the charging speed of the battery during the preset SOC section, and

wherein the charging speed of the battery before and after the preset SOC section are approximately identical to each other.