Abstract: A fuel cell assembly having a flow distribution subassembly that comprises four sets of flow channels, the first set facing an anode for distribution of a fuel reactant to said anode, the second set facing a cathode for distribution of an oxidant to said cathode, the third set in flow communication with said second set and in heat transfer relation with at least one of said anode and said cathode, and the fourth set receiving a coolant different from said oxidant.

Abstract: A fuel cell assembly having a flow distribution subassembly that comprises four sets of flow channels, the first set facing an anode for distribution of a fuel reactant to said anode, the second set facing a cathode for distribution of an oxidant to said cathode, the third set in flow communication with said second set and in heat transfer relation with at least one of said anode and said cathode, and the fourth set receiving a coolant different from said oxidant.

Abstract: A fuel cell assembly having a flow distribution subassembly that comprises four sets of flow channels, the first set facing an anode for distribution of a fuel reactant to said anode, the second set facing a cathode for distribution of an oxidant to said cathode, the third set in flow communication with said second set and in heat transfer relation with at least one of said anode and said cathode, and the fourth set receiving a coolant different from said oxidant.

Abstract: A fuel cell stack receiving oxidant into a compressor progressively pressurizing the oxidant from an inlet pressure to a discharge pressure where a fluid connection exists between oxidant effluent from the fuel cell stack and the progressively pressurized oxidant within the compressor at an intermediate pressure between the compressor inlet pressure and the compressor discharge pressure. A pressure regulator is provided for managing pressure of the cell oxidant effluent recycle flow to the compressor, and measurements are taken of compressor power consumption and/or compressor discharge temperature, humidity, and/or pressure to further control the regulator.

Abstract: A multi-stage compressor system that compresses air supplied to a cathode of a fuel cell system includes a first stage compressor that compresses inlet air to provide a first pressurized air stream at a first pressure. A second stage compressor includes a compression unit that compresses the first pressurized air stream to a second pressurized air stream at a second pressure. A drive unit drives the compression unit using expansion energy of an exhaust stream of the fuel cell. A first heat exchanger enables heat transfer between the second pressurized air stream and the exhaust stream to heat the exhaust stream.

Abstract: A fuel cell system that employs a recuperative heat exchanger to provide additional cooling for the compressed charge air applied to the cathodes of the fuel cells in the fuel cell stack. The cathode exhaust gas is applied to the recuperative heat exchanger so that the cathode exhaust gas cools the charge air heated by the compressed air. A cathode exhaust gas expander is provided in combination with the recuperative heat exchanger that uses the energy in the heated cathode exhaust gas to power the charge air compressor. An anode exhaust gas combustor can be provided that burns residual hydrogen in the anode exhaust gas to further heat the cathode exhaust gas before it is applied to the expander.

Abstract: A method of regulating a relative humidity of a gas supplied to a cathode side of a fuel cell stack includes controlling a flow of feedback gas from the cathode side to a compressor to adjust the relative humidity of the gas. Injected water into the compressor is vaporized in the compressor to further adjust the relative humidity of the gas. The gas is discharged at a pressure that is sufficient for use in the fuel cell stack. Water is injected into the compressor. Vaporizing is achieved using heat generated through compression. A compression pressure of the compressor is adjusted based on a quantity of the water to vaporize the water therein.

Abstract: A fuel cell assembly having a flow distribution subassembly that comprises four sets of flow channels, the first set facing an anode for distribution of a fuel reactant to said anode, the second set facing a cathode for distribution of an oxidant to said cathode, the third set in flow communication with said second set and in heat transfer relation with at least one of said anode and said cathode, and the fourth set receiving a coolant different from said oxidant.

Abstract: A fuel cell stack receiving oxidant into a compressor progressively pressurizing the oxidant from an inlet pressure to a discharge pressure where a fluid connection exists between oxidant effluent from the fuel cell stack and the progressively pressurized oxidant within the compressor at an intermediate pressure between the compressor inlet pressure and the compressor discharge pressure. A pressure regulator is provided for managing pressure of the cell oxidant effluent recycle flow to the compressor, and measurements are taken of compressor power consumption and/or compressor discharge temperature, humidity, and/or pressure to further control the regulator.

Abstract: The present invention provides a method of operating a fuel cell system and a fuel cell system that can adjust the operating pressure of the fuel cell system to maximize efficiency. This present invention recognizes that under certain operating conditions appropriately matched operating pressures enable a substantially more efficient system operation. The method of the present invention and the fuel cell system of the present invention incorporate the recognition that a higher system efficiency can be achieved when the operating pressure produced by the air compressor is matched to the prevailing operating temperature of the fuel cell system.

Abstract: A multi-stage compressor system that compresses air supplied to a cathode of a fuel cell system includes a first stage compressor that compresses inlet air to provide a first pressurized air stream at a first pressure. A second stage compressor includes a compression unit that compresses the first pressurized air stream to a second pressurized air stream at a second pressure. A drive unit drives the compression unit using expansion energy of an exhaust stream of the fuel cell. A first heat exchanger enables heat transfer between the second pressurized air stream and the exhaust stream to heat the exhaust stream.

Abstract: A method of regulating a relative humidity of a gas supplied to a cathode side of a fuel cell stack includes controlling a flow of feedback gas from the cathode side to a compressor to adjust the relative humidity of the gas. Injected water into the compressor is vaporized in the compressor to further adjust the relative humidity of the gas. The gas is discharged at a pressure that is sufficient for use in the fuel cell stack. Water is injected into the compressor. Vaporizing is achieved using heat generated through compression. A compression pressure of the compressor is adjusted based on a quantity of the water to vaporize the water therein.

Abstract: A fuel cell system that employs a recuperative heat exchanger to provide additional cooling for the compressed charge air applied to the cathodes of the fuel cells in the fuel cell stack. The cathode exhaust gas is applied to the recuperative heat exchanger so that the cathode exhaust gas cools the charge air heated by the compressed air. A cathode exhaust gas expander is provided in combination with the recuperative heat exchanger that uses the energy in the heated cathode exhaust gas to power the charge air compressor. An anode exhaust gas combustor can be provided that burns residual hydrogen in the anode exhaust gas to further heat the cathode exhaust gas before it is applied to the expander.

Abstract: A fuel cell system that employs a recuperative heat exchanger to provide additional cooling for the compressed charge air applied to the cathodes of the fuel cells in the fuel cell stack. The cathode exhaust gas is applied to the recuperative heat exchanger so that the cathode exhaust gas cools the charge air heated by the compressed air. A cathode exhaust gas expander is provided in combination with the recuperative heat exchanger that uses the energy in the heated cathode exhaust gas to power the charge air compressor. An anode exhaust gas combustor can be provided that burns residual hydrogen in the anode exhaust gas to further heat the cathode exhaust gas before it is applied to the expander.

Abstract: The present invention provides a method of operating a fuel cell system and a fuel cell system that can adjust the operating pressure of the fuel cell system to maximize efficiency. This present invention recognizes that under certain operating conditions appropriately matched operating pressures enable a substantially more efficient system operation. The method of the present invention and the fuel cell system of the present invention incorporate the recognition that a higher system efficiency can be achieved when the operating pressure produced by the air compressor is matched to the prevailing operating temperature of the fuel cell system. It is emphasized that this abstract is provided to comply wit the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that is will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).