US Patent 7195831 Fuel cell and method of controlling the same

A fuel cell wherein reactive gas or coolant flow directions within single-cell internal passages may be changed by switching the positions of flow control means such as electromagnetic valves in order to alter flow directions and flow velocities in accordance with fuel cell operating states. Altering flow to different directions within the internal passages, such as to a second flow direction perpendicular to a first flow direction, permits control of gas flow to combat fuel cell flooding, wherein the altered reactant gas flow causes accumulated water to be discharged from the cell. Such flow control further permits control of gas and coolant temperatures to optimize cell moisture distribution and control.