Patent ID: 7553569

Claim:
A method of operating a fuel cell system having at least one fuel cell stack and at least two discrete cathode sides, the method comprising: (a) determining a first power demand on the at least one fuel cell stack; (b) determining first and second stoichiometric quantities of cathode reactant to supply to at least one of the at least two cathode sides based on the first power demand; (c) supplying a cathode reactant stream; (d) routing a first portion of said cathode reactant stream to a first one of the cathode sides via a first cathode reactant flow path; (e) routing a second portion of said cathode reactant stream to a second one of the cathode sides via a second cathode reactant flow path; and (f) varying a quantity of cathode reactant in at least one of said first and second portions of said cathode reactant stream between the determined first and second stoichiometric quantities, which remain unchanged as a power demand on the fuel cell stack remains constant at the first power demand, such that at least one of the first and second cathode sides receives cathode reactant at a quantity that varies back and forth between the first and second stoichiometric quantities over time while the power demand on the fuel stack remains constant at the first power demand.