Patent ID: 9660280
Date: 2017-05-23
CPC Classifications: H01M,Y02E,Y02P

Claim:
1. A method of controlling a fuel cell system, comprising: draining, water from the fuel cell system by opening a drain-purge valve when a production amount of the water in the fuel cell system exceeds a capacity of a water trap; determining, by a controller, an opening time, during which the drain-purge valve remains open after the draining has completed, depending on a hydrogen concentration of an anode side and a target hydrogen concentration; and purging hydrogen by maintaining the drain-purge valve in an opened state for the determined opening time, wherein the determining of the opening time of the drain-purge valve includes: calculating a correction accumulated electric charge amount based on an output current of the fuel stack and a correction factor that becomes different depending on the output current; calculating a hydrogen concentration depending on the calculated correction accumulated electric charge amount; and determining the opening time according to the hydrogen concentration and a preset target hydrogen concentration, wherein the correction factor is changed depending on an average current change rate and the average current change rate is determined depending on a comparison result between an average value of all current data and an average value of a preset number of current data measured last among all the current data.