Apparatus for improving the cold starting capability of an electrochemical fuel cell

An electric power generation system comprising:

• (a) a fuel cell stack connectable to an external electrical circuit for supplying electric current to said external circuit, said stack comprising at least one solid polymer fuel cell, and reactant stream passages for directing reactant streams through said at least one fuel cell;
• and
• (b) a humidifier in fluid communication with at least one of said reactant stream passages, for humidifying a reactant stream supplied to said fuel cell stack;
• and
• (c) a humidifier bypass system comprising at least one bypass conduit for directing said reactant stream to said stack in fluid isolation from said humidifier and a bypass control device for selectively directing flow of said reactant stream to said fuel cell stack through either of said humidifier and said humidifier bypass conduit.

An electric power generation system comprising

• (a) a fuel cell stack connectable to an external electrical circuit for supplying electric current to said external circuit, said stack comprising at least one solid polymer fuel cell, and reactant stream passages for directing reactant streams through said at least one fuel cell;
• (b) apparatus for humidifying at least one of said reactant streams supplied to said fuel cell stack;
• and
• (c) a humidifier bypass system comprising apparatus for directing at least one of said reactant streams to said stack in fluid isolation from said humidifying apparatus, and apparatus for selectively directing flow of said reactant streams to said fuel cell stack through said humidifying apparatus or in fluid isolation from said humidifying apparatus.