The present application relates to a battery charging method and charging system which can prevent degradation of a battery and enhance the lifetime characteristics thereof. In one aspect, the charging method includes charging a battery at a first C-rate higher than a reference C-rate, wherein the C-rate represents charge or discharge current/a rated capacity of the battery. The charging method also includes charging the battery at a second C-rate lower than the reference C-rate. The charging of the battery at the first C-rate includes at least one rest period for temporarily stopping the charging of the battery.