United Technologies Corporation

International Fuel Cells, LLC

The United States of America As Represented by the United States

Utc Fuel Cells, LLC

Utc Power Corporation

Lawrence J Bregoli

Ned Emidio Cipollini

Francis J Luczak

Timothy W Patterson

Jung S Yi

Timothy A Bekkedahl

Richard D Breault

Carl Anthony Reiser

Tommy Skiba

Donald L Maricle

Deliang Yang

Richard D Sawyer

Chris Vargas

Jeremy P Meyers

Craig R Schroll

Calvin L Bushnell

H Russell Kunz

Margaret M Steinbugler

Emily A Dykeman

Stanley W Smith

Jonathan Puhalski

Marianne Pemberton

A fuel cell power plant includes a fuel cell having a membrane electrode assembly (MEA), disposed between an anode support plate and a cathode support plate, the anode and/or cathode support plates include a hydrophilic substrate layer having a predetermined pore size. The pressure of the reactant gas streams is greater than the pressure of the coolant stream, such that a greater percentage of the pores within the hydrophilic substrate layer contain reactant gas rather than water. Any water that forms on the cathode side of the MEA will migrate through the cathode support plate and away from the MEA. Controlling the pressure also ensures that the coolant water will continually migrate from the coolant stream toward the anode side of the MEA, thereby preventing the membrane from becoming dry. Proper pore size and a pressure differential between coolant and reactants improves the electrical efficiency of the fuel cell.

Fuel cell having a hydrophilic substrate layer

Each cell of a fuel cell stack is provided, between the anodeand cathodes, with either (a) a permanent shunt () which may be a discrete resistor (), a diode (), a strip of compliant carbon cloth (), or a small amount of conductive carbon black () in the ionomer polymer mixture of which the proton exchange membrane () is formed, or (b) a removeable shunt such as a conductor () which may be rotated into and out of contact with the fuel cell anodes and cathodes, or a conductor () which may be urged into contact by means of a shape memory alloy actuator spring (), which may be heated.

Reducing fuel cell cathode potential during startup and shutdown

The reactant manifolds and corners of a molten carbonate fuel cell stack are sealed with particulate lithium aluminate members which are sufficiently porous so as to resist significant electrolyte migration therethrough. The seal members which are disposed in vertical planes of the stack are preferentially formed from lithium aluminate grains which are bonded together by a silica-free glass binder. The seal members which are disposed in horizontal planes in the stack are preferably formed from lithium aluminate grains which are bonded together by surface hydrolysis. Alumina-clad stainless steel labyrinth seal members are associated with each of the horizontal seal members to inhibit electrolyte migration from the cell electrolyte matrices to the vertical seal members.

Edge seals for molten carbonate fuel cell stacks

A method for making a fuel cell electrode is disclosed. A layer of hydrophobic polymer and an electro-catalyst is deposited on the surface of a porous electrode substrate and press-sintered by heating the catalyst layer to a temperature between the melting point and decomposition temperature of the polymer and simultaneously compressing the layer at a pressure between 20 pounds per square inch and 100 pounds per square inch. The heating and compressing are continued for a time period of between 10 minutes and 20 minutes. A fuel cell electrode made by the above method and a method for generating electricity using such an electrode are also disclosed. A press-sintered fuel cell electrode provides improved peak performance as well as improved tolerance to electrolyte solidification.

Fuel cell electrode and method of making and using same

An integrated current collecting electrode for a molten carbonate fuel cell includes a corrugated metal conductive strip positioned in contact with a catalyst layer. The corrugations of the metal strip form a plurality of gas channels immediately adjacent the surface of the catalyst through which a reactant gas flows. Each channel is filled with a particulate material to maintain separation between the metal strip and the catalyst in ensuring gas channel integrity. The catalyst may be in the form of a compacted, particulate material provided the particle size of the material within the gas channels is larger than that of the catalyst particles to prevent catalyst migration to the metal conductor and provide reactant gas access to the catalyst layer. The gas channels formed by the corrugations of the metal strip are arranged in an offset pattern along the direction of gas flow for improved reactant gas distribution to the catalyst layer. The particulate material positioned within the gas flow channels may be a ceramic conductor such as a perovskite or a spinel for enhanced current collection.

Integrated current collector and catalyst support

Thru-cracks in the electrolyte retaining matrix of a molten carbonate fuel cell caused by thermal cycling of the cell between operating and room temperature are prevented by an improved matrix comprising a major proportion of submicron support particles and a minor proportion, perhaps only a few percent, of much larger crack attenuator particles. In one embodiment wherein the electrolyte is to be a binary lithium-potassium carbonates composition, the matrix comprises 90 volume percent submicron lithium aluminate support particles and 10 volume percent alumina crack attenuator particles with an average size of 100 microns.

Electrolyte matrix for molten carbonate fuel cells

Porous cathodes for molten carbonate type fuel cells are made from perovskites. The perovskites tested to date all appear to be good cathode catalysts for the reduction of oxygen in molten carbonate electrolyte and are also stable in the electrolyte.

Cathodes for molten carbonate fuel cells

A fuel cell is disclosed in which the cathode is a gaseous diffusion fuel cell electrode operating with an acid electrolyte and nitrogen dioxide (NO.sub.2) alone or with oxygen. The cathode half cell reaction produces nitric oxide (NO) and water and the NO.sub.2 is externally regenerated by reaction of NO with oxygen to produce the nitrogen dioxide for reuse in the cell. When both NO.sub.2 and oxygen are used, oxidation of the NO formed back to the NO.sub.2 occurs within the cathode itself so it is possible to get more than 100% utilization of the NO.sub.2 in the fuel cell.

Nitrogen dioxide regenerative fuel cell

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Southwick, MA, United States of America

Lawrence J Bregoli