Ballard Power Systems Corporation

Daimler Ag

Ford Motor Company Limited

Geer Products Ltd.

Emerson Richard Gallagher

Keith M Martin

Paul Po Hang Fong

Samira Barakat

Russell H Barton

Peter Robert Gibb

Ian Stewart

Michael P Sexsmith

Neil V Davis

Alan Young

David Brown

George Alexander Skinner

Darcy McGowan

Maura H Malone

Horst Thumm

David Myers

Laura Kraft

Janice Blok

Doug Manarin

Yingduo Chen

Svetlana Loif

Oliver Clemens

A method is provided for operating a fuel cell stack with improved performance recovery from sub-saturated conditions, the method comprising setting an alert for the performance recovery of the fuel cell stack, performing at least one oxidant starvation by supplying oxidant at a stoichiometric ratio below 1 to the fuel cell stack in at least one pulse for a preset amount of time and at low current while the fuel cell stack does not generate power. The fuel cell system with an improved performance recovery comprises a shorting circuit which is connected to the fuel cell stack at predetermined times (startup, shutdown or standby mode) and an air compressor powered by a DC-DC converter which supplies a predetermined number of oxidant pulses of a predetermined duration to the fuel cell stack.

Method and system for operating an electrochemical fuel cell stack with improved performance recovery

A sealed membrane electrode assembly (MEA) and a method of sealing the MEA comprises the steps of providing a frame around a periphery of the MEA to form a framed MEA; providing a through-hole in the frame; placing the framed MEA into a seal mold, the seal mold comprising a reservoir region, a seal bead region, and at least one runner region; feeding a flow-processable seal material into the reservoir region in the seal mold that is aligned with the throughhole in the frame; feeding the flow-processable seal material from the reservoir region to the seal bead region through the at least one runner region; wherein a hydraulic diameter of the at least one runner region is less than a hydraulic diameter of the reservoir region.

Seal for solid polymer electrolyte fuel cell

A fuel cell stack assembly is disclosed comprising: a fuel cell stack comprising a first end plate, a second end plate, and a plurality of fuel cells interposed between the first and the second end plates; and a compression band which urges the first end plate towards the second end plate along a first face of the fuel cell stack and also along an opposing second face of the fuel stack in a stacking direction thereof in at least two passes on each face of fuel cells stack, thereby applying a compressive force upon the plurality of fuel cells in the fuel cell stack.

Compression apparatus for fuel cell stack

In solid polymer fuel cells employing framed membrane electrode assemblies, a conventional anode compliant seal is employed in combination with a cathode non-compliant seal to provide for a thinner fuel cell design, particularly in the context of a fuel cell stack. This approach is particularly suitable for fuel cells operating at low pressure.

An electrochemical fuel cell stack with integrated anode exhaust valves is disclosed, comprising a plurality of fuel cells, each fuel cell having an anode and at least one anode flow field channel, an anode exhaust manifold fluidly connected to the at least one anode flow field channel of each fuel cell, and a means for minimizing fluid backflow from the anode exhaust manifold into the anode flow field channels of the fuel cells. Methods for purging, and reducing fuel cell voltage variations within, the electrochemical fuel cell stack are also disclosed.

Electrochemical fuel cell stack with integrated anode exhaust valves

Improvements in freezing and sub-freezing startup time for an electrochemical fuel cell system may be observed by having a passive coolant microloop using two gear pump heads. During a cold start, a stack valve is initially fully closed and causes all system coolant arriving at the module to run through a driving gear pump head. This causes a driven gear pump head to recirculate coolant inside the module. In an embodiment, the stack valve is a thermostatic valve that begins to open as the coolant begins to warm up. This allows a small bleed of system coolant into the module and decreases the percentage of microloop recirculation. When operating temperature is reached, the thermostatic valve is fully open and system coolant inlet pressure on the driving gear pump head counteracts the pressure on the driven gear pump head, thus stopping recirculation.

Passive microcoolant loop for an electrochemical fuel cell

Electrochemical fuel cell stacks comprising a plurality of membrane electrode assemblies stacked in an alternating manner, such that the polarity of adjacent membrane electrode assemblies are opposite, are disclosed. The fuel cell stacks comprise a plurality of membrane electrode assemblies, each membrane electrode assembly comprising an anode fluid distribution layer, a cathode fluid distribution layer, a polymer electrolyte membrane interposed between the anode and cathode fluid distribution layers, an anode electrocatalyst layer interposed between the polymer electrolyte membrane and the anode fluid distribution layer, and a cathode electrocatalyst interposed between the polymer electrolyte membrane and the cathode fluid distribution layer, wherein the plurality of membrane electrode assemblies are stacked in an alternating manner such that the polarity of adjacent membrane electrode assemblies are opposite, and wherein the plurality of membrane electrode assemblies are externally jumpered. Methods for shutting down the fuel cell stacks are also disclosed.

Fuel cell stacks of alternating polarity membrane electrode assemblies

An electrochemical fuel cell comprises an anode electrocatalyst layer, a cathode electrocatalyst layer, a polymer electrolyte membrane interposed between the anode and cathode electrocatalyst layers, an anode flow field plate, a cathode flow field plate, an anode fluid distribution layer interposed between the anode flow field plate and the anode electrocatalyst layer, and a cathode fluid distribution layer interposed between the cathode flow field plate and the cathode electrocatalyst layer, wherein at least one of the anode and cathode fluid distribution layers decreases in permeability from an inlet to an outlet of the electrochemical fuel cell. Methods for making a substantially fluid impermeable sheet material having a non-uniform pattern of perforations are also provided.

Electrochemical fuel cell with fluid distribution layer having non-uniform permeability

A method fabricates fluid flow field plates that are suitable for use in an electrochemical fuel cell assembly. Pursuant to the method, a fluid flow field channel region such as, for example, substantially straight, parallel fluid flow field channels, is roller embossed in a sheet of compressible, electrically conductive material such as, for example, expanded graphite sheet material. A fluid distribution region such as, for example, a region containing manifold openings and supply channels, is then reciprocally embossed in the sheet material. A sheet pre-impregnated with a curable polymeric composition, such as pre-impregnated expanded graphite, can be employed, with the curing step being performed after the roller embossing and reciprocal embossing steps.

Method of fabricating fluid flow field plates

A process for impregnating a porous part is provided. In one embodiment, the process comprises impregnating the part with an impregnant that is not water soluble, and curing the impregnated part in a water bath. In another embodiment, the process comprises impregnating a part with an impregnant that is not water soluble, washing the impregnated part in a washing solution, and then curing the impregnated part in a water bath.

Process for impregnating porous parts

A flow field plate assembly for an electrochemical fuel cell comprises two flow field plates, each of which has channels formed on an inner surface of the plate. The plates are alignable with and engage each other such that their cooperating inner surfaces form at least one inner coolant fluid channel. The coolant channel has an essentially constant cross-sectional perimeter along its length, which is defined by the perimeters of the channels of the two plates and their difference in width at the cooperating plate surfaces. Additionally, a flow field plate assembly, which comprises a corrugated flow field plate and a staggered flow field plate, is structurally stronger under compressive load during the fuel cell operation.

Flow field plate assembly for an electrochemical fuel cell

A process for impregnating at least one porous part with an impregnant is provided comprising: (a) immersing the porous part(s) in impregnant; (b) measuring at least one parameter indicative of the buoyancy of the porous part(s) as the impregnant impregnates the parts; and (c) interrupting impregnation when the measured parameter(s) indicates a predetermined level of impregnation is achieved. An apparatus for impregnating porous parts comprises a vessel for holding the porous part(s) and an impregnant, and a measuring device for measuring at least one parameter indicative of the buoyancy of the porous part(s) immersed in the impregnant within the vessel.

Control process for impregnating porous parts and apparatus therefor

A process for impregnating at least one porous part with an impregnant comprises: (a) immersing at least one porous part in a fixed volume of impregnant, (b) measuring at least one parameter indicative of the effective volume of the impregnant as the impregnant impregnates the porous part(s), and (c) interrupting impregnation when the measured parameter(s) indicates a desired level of impregnation is achieved. An apparatus for impregnating porous parts comprises a vessel for holding at least one porous part and a fixed volume of impregnant, and at least one device for measuring the change in effective volume of the impregnant within the vessel.

A wheelchair has a pair of wheels supporting a frame, a pair of front castors, a seat, and an anti-tipping device on the frame. The anti-tipping device includes an extensible and retractable displacement mechanism including an actuating member manually accessible by a person seated on the seat for displacing a ground engagement member between a forwardly retracted inoperative position, in which the ground engagement member is retracted beneath the seat, and a rearwardly extended operative or deployed position, in which the ground engagement member is extended rearwardly from the frame.

Growing community of inventors

Vancouver, Canada

Emerson Richard Gallagher