Method and Device for Controlling State of Charge

A state of charge (SOC) control method of controlling the SOC of a fuel cell electric vehicle (FCEV) in response to a change in altitude of the FCEV is provided. The method may include setting a first altitude at a start time of operating the FCEV; determining, based on a measurement value of an accelerometer, a travel distance and a first amount of altitude change during a predetermined time duration since the start time; determining an adjustment time for adjusting past driving data of the FCEV; determining, based on the adjustment time, a second amount of altitude change; determining, based on the second amount of altitude change, a target state of charge (SOC) as an input parameter; determining, based on a comparison between a current SOC and the target SOC, a required amount of additional fuel cell (FC) power generation; and controlling the FCEV.