Utc Fuel Cells, LLC

International Fuel Cells, LLC

Utc Power Corporation

Deliang Yang

Carl Anthony Reiser

Richard D Sawyer

Jung S Yi

Richard D Breault

Leslie L Van Dine

David A Condit

Robin J Guthrie

Jeremy P Meyers

Emily A Dykeman

Michael L Perry

Albert P Grasso

John C Trocciola

Paul R Margiott

John H Whiton

Glenn W Scheffler

Tommy Skiba

Timothy W Patterson

Chris Vargas

Gennady Resnick

Leonard J Bonville

Robert R Fredley

Margaret M Steinbugler

Thomas F Fuller

Lawrence J Bregoli

Yu Wang

George S Hirko

Harold T Couch

Javier Resto

Timothy A Bekkedahl

Brian F Dufner

John Donahue

Elizabeth A Allen

Melanie A Blondin

James R Geschwindt

Emily A Ballinger

Constance J King

An inlet fuel distributor (-) has a permeable baffle () between a fuel supply pipe () and a fuel inlet manifold () causing fuel to be uniformly distributed along the length of the fuel inlet manifold. A surface () may cause impinging fuel to turn and flow substantially omnidirectionally improving its uniformity. Recycle fuel may be provided () into the flow downstream of the fuel inlet distributor. During startup, fuel or inert gas within the inlet fuel distributor and the fuel inlet manifold may be vented through an exhaust valve () in response to a controller () so as to present a uniform fuel front to the inlets of the fuel flow fields ().

Permeable inlet fuel gas distributor for fuel cells

A procedure for starting up a fuel cell system that is disconnected from its primary load and has both its cathode and anode flow fields filled with air includes initiating a flow of air through the cathode flow field and rapidly displacing the air in the anode flow field by delivering a flow of fresh hydrogen containing fuel into the anode flow field, and thereafter connecting the primary load across the cell. Sufficiently fast purging of the anode flow field with hydrogen prior to connecting the cells to the load eliminates the need for purging the anode flow field with an inert gas, such as nitrogen, upon start-up.

Procedure for starting up a fuel cell system using a fuel purge

A cell stack assembly () coolant system comprises a coolant exhaust conduit () in fluid communication with a coolant exhaust manifold () and a coolant pump (). A coolant inlet conduit () enables transportation of the coolant to the coolant inlet manifold. The coolant system further includes a bypass conduit () in fluid communication with the coolant exhaust manifold and the coolant inlet manifold, while a bleed valve () is in fluid communication with the coolant exhaust conduit and a source of gas. Operation of the bleed valve enables venting of the coolant from the coolant channels, and through a shut down conduit (). An increased pressure differential between the coolant and reactant gases forces water out of the pores in the electrode substrates (). An ejector () prevents air form inhibiting the pump. Pulsed air is blown () through the coolant channels to remove more water.

Method and apparatus for the operation of a cell stack assembly during subfreezing temperatures

A procedure for starting up a fuel cell system that is disconnected from its primary load and that has air in both its cathode and anode flow fields includes a) connecting an auxiliary resistive load across the cell to reduce the cell voltage; b) initiating a recirculation of the anode flow field exhaust through a recycle loop and providing a limited flow of hydrogen fuel into that recirculating exhaust; c) catalytically reacting the added fuel with oxygen present in the recirculating gases until substantially no oxygen remains within the recycle loop; disconnecting the auxiliary load; and then d) providing normal operating flow rates of fuel and air into respective anode and cathode flow fields and connecting the primary load across the cell. The catalytic reaction may take place on the anode or within a catalytic burner disposed within the recycle loop. The procedure allows start-up of the fuel cell system without the use of an inert gas purge while minimizing dissolution of the catalyst and corrosion of the catalyst support during the start-up process.

Procedure for starting up a fuel cell system having an anode exhaust recycle loop

A fuel cell includes a membrane electrode assembly () having a first reactant flow field () secured adjacent a first or second surface () of the assembly () for directing flow of a first reactant adjacent the first or second surface of the assembly (). The first reactant flow field () defines a plurality of two-pass circuits (), and each two-pass circuit () is in fluid communication with both a first reactant inlet () for directing the first reactant into the fuel cell (), and with a first reactant outlet () for directing the first reactant out of the fuel cell (). The plurality of two-pass circuits () facilitate water movement () toward the reactant inlet () to aid in passive maintenance of fuel cell () water balance.

Fuel cell with passive water balance

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

A procedure for shutting down an operating fuel cell system includes disconnecting the primary electricity using device and stopping the flow of hydrogen containing fuel to the anode, followed by quickly displacing the residual hydrogen with air by blowing air through the anode fuel flow field. A sufficiently fast purging of the anode flow field with air eliminates the need for purging with an inert gas such as nitrogen.

Procedure for shutting down a fuel cell system using air purge

A reduced volume fuel cell stack ( ) includes a plurality of thin fuel cells ( ) and a plurality of thick fuel cells ( ). The thin fuel cells include water management channels ( A, B, C, D) and the thick fuel cells include cooling channels ( A, B, C, D). At least two thin fuel cells ( ) are secured adjacent each other and adjacent each thick fuel cell ( ) within the stack ( ). The water management channels ( A, B, C, D) have a depth that is at least four times less than a depth of the cooling channels ( A, B, C, D) so that volume, weight and water content of the stack ( ) are reduced.

Fuel cell stack having a reduced volume

A proton exchange membrane (PEM) fuel cell includes fuel and oxidant flow field plates ( ) having fuel and oxidant channels ( ), and water channels, the ends ( ) of which that are adjacent to the corresponding reactant gas inlet manifold ( ) are dead ended, the other ends ( ) draining excess water into the corresponding reactant gas exhaust manifold ( ). Flow restrictors ( ) maintain reactant gas pressure above exit manifold pressure, and may comprise interdigitated channels ( ). Solid reactant gas flow field plates have small holes ( ) between reactant gas channels ( ) and water drain channels ( ). In one embodiment, the fuel cells of a stack may be separated by either coolant plates ( ) or solid plates ( ) or both. In a second embodiment, coolant plates ( ) have weep holes ( ) that inject water into the ends ( ) of the reactant gas water channels which are in the region of the inlet manifold ( ), thereby assuring humidification of the reactants.

Passive water management fuel cell

The invention is a bi-zone water transport plate for a fuel cell wherein the plate includes a water permeability zone and a bubble barrier zone. The bubble barrier zone extends between all reactive perimeters of the plate, has a pore size of less than 20 microns, and has a thickness of less than 25 percent of a shortest distance between opposed contact surfaces of the plate. The water permeability zone has a pore size of at least 100 percent greater than the pore size of the bubble barrier zone, and has a thickness of greater than 75 percent of the shortest distance between the opposed contact surfaces of the plate. By having a separate bubble barrier zone, the plate affords enhanced water permeability while the bubble barrier maintains a gas seal.

Bi-zone water transport plate for a fuel cell

A coolant system is proposed for addressing temperature concerns during start-up and shut-down of a cell stack assembly. The coolant system comprises a coolant exhaust conduit in fluid communication with a coolant exhaust manifold and a coolant pump, the coolant exhaust conduit enabling transportation of exhausted coolant away from a coolant exhaust manifold. A coolant return conduit is provided to be in fluid communication with a coolant inlet manifold and a coolant pump, the coolant return conduit enabling transportation of the coolant to the coolant inlet manifold. The coolant system further includes a bypass conduit in fluid communication with the coolant exhaust conduit and the coolant return conduit, while a bleed valve is in fluid communication with the coolant exhaust conduit and a gaseous stream. Operation of the bleed valve enables venting of the coolant from the coolant channels, and through said bypass conduit.

A fuel cell stack ( ) has a two-pass fuel flow field ( ) extending from a fuel inlet ( ) around a fuel turnaround manifold ( ) to a fuel outlet ( ). The stack has two air flow fields ( ) extending from an air inlet ( ) through an air turnaround manifold ( ) to an air outlet ( ), the air outlet ( ) being adjacent to the fuel outlet ( ). The stack includes a coolant flow field ( ) which extends from a coolant inlet ( ) to a coolant outlet ( ), the coolant inlet being adjacent to both the fuel outlet and the air outlet. The fluid flow configuration provides lower temperature, a more even temperature profile, a higher coolant exit temperature, and permits operation with higher air utilization and lower coolant flow.

Fluid flow control for cool, efficient fuel cell operation

PEM fuel cell performance losses caused by phenomena occurring during normal cell operation are recovered by periodically reducing the cathode potential to about 0.6 volts or less, and preferably to 0.1 volt or less. Once the cathode potential is reduced to the desired low level, it is maintained at or below that level for a period of time. The lower the potential to which the cathode is brought, the more quickly regeneration will occur. After regeneration, the cell, when returned to normal operation, will operate at a higher performance level.

Method and apparatus for regenerating the performance of a PEM fuel cell

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.

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Torrance, CA, United States of America

Deliang Yang