Abstract: A fuel cell system comprises a fuel cell, a fuel gas passage through which a fuel gas containing an odorant and hydrogen gas supplied to the fuel cell flows, an oxidative gas passage through which an oxidative gas supplied to the fuel cell flows, a fuel off gas passage through which a fuel off gas discharged from the fuel cell flows, an oxidative off gas passage through which an oxidative off gas discharged from the fuel cell flows, and an odorant removal portion provided in the fuel off gas passage. The odorant removal portion removes the odorant after the fuel gas has been introduced into the fuel cell.

Abstract: A fuel cell system includes a hydrogen gas supply portion for supplying a fuel cell with hydrogen gas. The hydrogen gas supply portion includes an odorant treatment portion for treating an odorant in a mixed gas containing given hydrogen gas and the odorant. The odorant treatment portion includes an odorant removal portion and an air blower. The odorant removal portion contains a porous adsorbent for adsorbing the odorant contained in the mixed gas and a catalyst for promoting decomposition of the adsorbed odorant. The air blower decomposes the adsorbed odorant. Thus, the odorant treatment portion can perform a function of supplying the fuel cell with hydrogen gas by adsorbing the odorant contained in the mixed gas, and a function of recovering its adsorption capacity by decomposing the adsorbed odorant.

Abstract: 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.

Abstract: A fuel cell system in which warm up of the fuel cell is promoted at the time of starting and the fuel cell is operated under steady condition in a short time. The fuel cell has a plurality of power generator portions. A circulating water passage connected to the power generator portions are changed so that circulating water flows in just part of the generator when the temperature of the fuel cell is not higher than the predetermined value.