FOUR-FLUID BIPOLAR PLATE FOR FUEL CELL AND METHODS OF OPERATION

A four-fluid bipolar plate for a fuel cell includes a nonporous sub-plate comprising a first reactant half-plate joined to a second reactant half-plate. The nonporous sub-plate includes an internal coolant passage network having coolant flow field passages extending across an active area of the fuel cell. The nonporous sub-plate defines fuel supply and fuel return internal manifolds, oxidant supply and oxidant return internal manifolds, water management supply and water management return internal manifolds, and coolant supply and coolant return internal manifolds. In one embodiment, a method of preventing corrosion at a carbon/metal interface in a fuel cell is disclosed. In other embodiments, a method of operating a four-fluid fuel cell in thermal boost mode is disclosed, and a method of accumulating and retaining product water in a four-fluid fuel cell is disclosed.