초록 ▼

A stack of fuel cells operating on gaseous reactants includes an ejector in integral heat exchange relationship with the stack for recirculating one of the reactant gases through the cells of the stack. The recirculating reactant is continuously heated by waste heat from the cells as it recirculates

A stack of fuel cells operating on gaseous reactants includes an ejector in integral heat exchange relationship with the stack for recirculating one of the reactant gases through the cells of the stack. The recirculating reactant is continuously heated by waste heat from the cells as it recirculates thereby preventing condensation of water from the recirculating reactant gas and thereby maintaining the dew point constant from the time the reactant gas leaves the cells until it is mixed with fresh reactant in the ejector. The fresh reactant gas is preheated prior to being introduced to the ejector so that there is no condensation throughout the entire loop. The recirculation rate relative to the amount of fresh reactant can be controlled to regulate the dew point at the entrance to the cells to best advantage. By this invention flooding of the electrodes or drying of the electrodes does not occur.

대표청구항 ▼

In a fuel cell stack comprising a plurality of fuel cells each including a fuel electrode and an oxidant electrode spaced apart defining an electrolyte compartment therebetween, means constructed and arranged with said cells to define a reactant gas space on the nonelectrolyte side of each electrode

In a fuel cell stack comprising a plurality of fuel cells each including a fuel electrode and an oxidant electrode spaced apart defining an electrolyte compartment therebetween, means constructed and arranged with said cells to define a reactant gas space on the nonelectrolyte side of each electrode, said reactant gas spaces including a fuel gas space on the nonelectrolyte side of each fuel electrode and an oxidant gas space on the nonelectrolyte side of each oxidant electrode, each of said gas spaces having an inlet and an outlet, the improvement to said stack comprising: an ejector for delivering and recirculating one of said reactant gases through said cells, said ejector constructed and arranged to be integral with and in heat exchange relationship with the cells of said stack, said ejector including primary inlet means, secondary inlet means, and outlet means; first conduit means connected to said ejector primary inlet means for delivering preheated reactant gas into said ejector primary inlet means; second conduit means connecting said ejector outlet means to said inlets of said recirculating reactant gas spaces; and third conduit means connecting said recirculating reactant gas space outlets with said ejector secondary inlet means, said secondary inlet means including means for establishing the recirculation rate of reactant gas through said ejector.