Patent ID: 7974796

Claim:
A fully-charged battery capacity detection method of detecting a capacity of a battery, the method comprising: detecting, via a voltage detection circuit, first and second no-load voltages (VOCV 1 , VOCV 2 ) of the battery at a first no-load timing and a second no-load timing during which the battery is brought to a no-load state, respectively; determining whether the detected first no-load voltage (VOCV 1 ) falls within a predetermined voltage range, and determining, when the first no-load voltage (VOCV 1 ) falls within the predetermined voltage range, first and second remaining capacities (SOC 1 [%], SOC 2 [%]) of the battery based on the first and second no-load voltages (VOCV 1 , VOCV 2 ), respectively; calculating a remaining capacity variation rate (δS [%]) based on a difference between the determined first and second remaining capacities (SOC 1 [%], SOC 2 [%]); calculating a capacity variation value (δAh) of the battery based on an integrated value of charging and discharging currents of the battery to be charged/discharged from the first no-load timing to the second no-load timing; and calculating a fully-charged capacity (Ahf) of the battery based on the remaining capacity variation rate (δS [%]) and the capacity variation value (δAh) according to the following formula: Ahf=δAh /(δ S/ 100).