Patent ID: 6821668
Filing Date: 2004-11-23
Classification: H01M,Y02E

Abstract:
A fuel cell stack comprising:a cascaded fuel flow field having at least a first group of fuel cells receiving fuel from a source, a second group of fuel cells normally receiving fuel from said first group, and a third group of fuel cells normally receiving fuel from said second group of fuel cells, and in which the number of fuel cells in each group exceeds the number of fuel cells in any group downstream thereof in said fuel flow field; at least one fuel inlet means for inputting fuel settable in either of two conditions, operable in a first condition to cause fuel to flow directly from said source only into said first group of fuel cells, and operable in a second condition to cause fuel to flow directly from said source into each of said groups of fuel cells without such fuel first flowing through any other group of fuel cells; at least one fuel outlet means for outputting fuel settable in either of two conditions, operable in a first condition to cause fuel to flow directly to exhaust only from a last group of said fuel cells, and operable in a second condition to cause fuel to flow from each of said groups of fuel cells directly to exhaust without such fuel first flowing through any other group of fuel cells; and fuel inlet and fuel exhaust manifolds, said fuel inlet means being within said fuel inlet manifold and said fuel outlet means being within said fuel exhaust manifold.