International Fuel Cells, LLC

Utc Power Corporation

Utc Fuel Cells, LLC

Clearedge Power Corporation

Robert R Fredley

Richard D Breault

Glenn W Scheffler

Bhimashankar V Nitta

Paul R Margiott

John L Preston

Deliang Yang

Richard D Sawyer

Robin J Guthrie

Francis J Luczak

Peter F Foley

Melanie A Blondin

Karen L Parenti

Christopher R Teeling

A fuel cellhas a liquid electrolyte, a cathode electrode, and an anode electrode. The fuel cell includes an electrolyte condensation zoneextending from an edgeof a first catalyst layeron the cathode electrode to an outer edgeof an edge sealsand. An anode electrode has an anode catalyst layerwith an end substantially coinciding with an inner edgeof the edge seals. The acid condensation zone is located near the reactant exit, so that electrolyte that has evaporated into the reactant stream can condense out before leaving the fuel cell for re-absorption back into the fuel cell.

Fuel cell with electrolyte condensation zone

An example fuel cell assembly includes a separator plate. Non-porous and hydrophobic flow field layers are associated with the separator plate. An electrolyte retaining matrix comprises silicon carbide powder and has a mean particle size of about 3 microns and a thickness of about 0.05 mm Hydrophilic substrates are associated with catalyst layers. The hydrophilic substrates are about 70% porous and have a void volume that is about 40% filled with transferable phosphoric acid in an initial condition. A condensation zone cools a vapor passing from the assembly to less than about 140&#xb0; C.

Fuel cell assembly having long life characteristics

A fuel cell assembly () has a plurality of characteristics that extend the useful life of the assembly. In one example, flow field layers are non-porous and hydrophobic such that they have an acid absorption rate of less than about 0.10 mg/khr-cm. An electrolyte retaining matrix has a reaction rate with phosphoric acid of less than about 0.010 mg/khr-cm. Hydrophilic substrates associated with catalyst layers have an initial transferable phosphoric acid content of less than about 25 mg/cm. A condensation zone provides an evaporative phosphoric acid loss rate that is less than about 0.17 mg/khr-cm.

A fuel cell system having a fuel cell stack () employing a phosphoric acid or other electrolyte, includes a non-reactive zone () in each of a group of fuel cells between corresponding coolant plates (), the coolant entering the coolant plates in an area adjacent to the non-reactive zones (). Each fuel cell has three-pass fuel flow fields, the first pass substantially adjacent to a third zone (), remote from the first zone, the second pass substantially adjacent to a second zone contiguous with the first zone, the coolant flowing () from a coolant inlet () through the first zone, to the far side of the second zone, and () from the near side of the second zone to the third zone and thence () to a coolant exit manifold (), which assures temperatures above 150&#xb0; C. (300&#xb0; F.), to mitigate CO poisoning of the anode within the reactive zones, and assuring temperatures below 140&#xb0; C. (280&#xb0; F.) to promote sufficient condensation of evaporated electrolyte in the non-reactive zones, so as to provide a long system life.

Fuel cell coolers with inverse flow and condensation zone

A fuel cell system having a fuel cell stack () employs a group of fuel cells between corresponding cooler plates (). The system utilizes single phase coolant, the outflow of the coolant plates () being divided into a flow () just sufficient to provide adequate steam () to a fuel reformer (), the remainder of the coolant outlet flowing () directly to heat recovery and utilization apparatus (), which may include fuel cell power plant accessories (), such as chillers or boilers.

Fuel cell in combined heat and electric power system

A PEM flow field system of coolant medium for preventing the formation and accumulation of gas bubbles, having a critical viscous pressure drop therein is provided. The water transport plate includes a coolant flow field channel therein having an input port and an exit port. The coolant flow field channel includes at least one upward flow channel portion, at least one downward flow channel portion. Coolant medium is fluidly routed through the coolant flow field channel of the water transport plate at a flow rate which results in a viscous pressure drop that is greater than the buoyancy of a gas bubble trapped within the coolant flow field channel to prevent the accumulation thereof within the coolant flow field channel.

System for preventing gas pocket formation in a PEM coolant flow field

An improved porous support layer is disclosed for use in an electrochemical cell such as a fuel cell having a proton exchange membrane ('PEM') as an electrolyte. In a preferred embodiment the porous support layer is positioned near and in fluid communication with an electrode to facilitate fluid transport to and away from each electrode. Each such porous support layer includes hydrophobic pores and hydrophilic pores integrated throughout the layer, wherein the hydrophobic pores are coated with a hydrophobic substance and include about 75 percent to about 95 percent of the total pore volume of the porous support layer, and the hydrophilic pores comprise about 25 percent to about 5 percent of the total pore volume of the porous support layer. The hydrophobic pores of the porous support layers facilitate gas transfer and restrict liquid water absorption into the hydrophobic pores, while the hydrophilic pores facilitate simultaneous liquid water transport through the layers. A method of manufacture of the porous support layer includes the steps of filling about 25 percent to about 5 percent of the pore volume of a carbon fiber substrate layer with a blocking material; applying a hydrophobic substance to the remaining, unfilled pore volume of the substrate layer; and heat treating the dried substrate at a temperature adequately high to volatilize or decompose the blocking material and fuse the hydrophobic substance to coat the hydrophobic pores to produce the porous support layer.

Porous support layer for an electrochemical cell

The present invention discloses a corrosion resistant fuel cell in which an ion impermeable protective layer is positioned over at least a portion of the noncatalyzed carbon based components. This layer prevents reactant ions or molecules form reaching localized high potential areas of these components and corroding the carbon material.

Corrosion resistant fuel cell assembly

Ammonia which is found in fuel cell fuel gases is removed therefrom by passing the fuel gas stream through a scrubber bed of porous carbon pellets containing phosphoric acid. The ammonia reacts with the phosphoric acid in the scrubber bed to form ammonium phosphate compounds which remain in the scrubber bed. The ammonia content of the fuel gas stream is thus lowered to a concentration of about one ppm or less. By maintaining the temperature of the fuel gas stream passing through the scrubber bed in a range of about 400.degree. F. to about 450.degree. F. sufficient phosphoric acid will also be evaporated from the scrubber bed to replace acid electrolyte lost during operation of the power plant. Adjustments in the temperature of the fuel gas flowing through the scrubber may be made in order to match electrolyte losses which occur during different operating phases of the power plant. The scrubber formed in accordance with this invention thus serves two functions, one being to remove ammonia from the fuel gas stream, and the other being to replenish electrolyte lost in the power plant during normal operation thereof.

System for treatment of acid fuel cell fuel gas stream

The cell stack assembly of a fuel cell power plant is provided with a cooling system which provides optimum cell operating temperatures across each cell in the stack and also produces an optimum amount of steam. The cooling system includes at least one bypass through which a fraction of the coolant is fed from the coolant inlet side of the stack to the coolant outlet side of the stack. The bypass ensures that a fraction of the coolant is not heated to its target operating temperatures as it passes through the stack. This results in a more uniform cell operating temperature profile from the coolant inlet to the coolant outlet side of each cell; and also results in a lessening of excess steam production in the power plant.

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Tolland, CT, United States of America

Robert R Fredley