Soc calcurating method for an integrated battery

According to an embodiment of the present invention, a method for calculating the SOC of an integrated battery to calculate the SOC of an integrated battery in a system which uses the integrated battery in which unit cells are combined in series or parallel includes: a step of defining a plurality of temperature ranges according to the operating temperature of the system and defining a plurality of current ranges according to the accumulated amount of discharge current in each temperature range to form a data set about temperature range versus current range; a step of measuring the temperature (T) and discharge current (I(t)) of the integrated battery for a unit time period and calculating the used capacity (Ah-used) of the integrated battery using the measured discharge current; a step of getting constant n and K for the Peuker′s equation using the values of the data set corresponding to the measured temperature and discharge current; and a step of calculating the available capacity (Ah_available) using the constant n and K and calculating the SOC.