Patents Assigned to Ballard Power Systems Inc.
  • Patent number: 6979504
    Abstract: A fuel cell system includes a fuel cell stack, a battery, and a control system. A power circuit couples the fuel cell system selectively between the fuel cell stack and the battery. The power circuit includes a battery supply switch responsive to a voltage across the fuel cell stack, and a stack supply switch responsive to an operating state of the fuel cell system. The battery supply switch uncouples the battery from an on-board power supply when a voltage across the fuel cell stack exceeds a first threshold voltage and couples the battery to the on-board power supply when the fuel cell stack voltage is less than a second threshold voltage. The stack supply switch couples power the fuel cell stack to the on-board power supply when in a running state. A diode-OR circuit couples the source with the highest potential to the on-board power supply.
    Type: Grant
    Filed: July 25, 2001
    Date of Patent: December 27, 2005
    Assignee: Ballard Power Systems Inc.
    Inventor: David S. Manery
  • Patent number: 6974647
    Abstract: A fuel cell fluid distribution layer, in one embodiment, comprises perforated graphite foil. The fluid distribution layer can have one or more reactant flow field channels formed in one or both major surfaces, one or more manifold openings, conductive filler on one or both major surfaces, conductive filler at least partially filling some or all perforations and/or an electrocatalyst one or both major surfaces.
    Type: Grant
    Filed: June 26, 2002
    Date of Patent: December 13, 2005
    Assignee: Ballard Power Systems Inc.
    Inventors: David P. Wilkinson, Juergen Stumper, Stephen A. Campbell, Michael T. Davis, Gordon Lamont
  • Patent number: 6969561
    Abstract: An electrochemical power generation system includes a fuel cell stack having an oxidant delivery system, an oxygen sensor for measuring the oxygen concentration of ambient air in the vicinity of the power generation system, and a hydrogen concentration sensor for measuring a hydrogen concentration in the ambient air in the vicinity of the power generation system. A controller is configured to cease operation of the power generation system, for example ceasing delivery of fuel to the fuel cell stack, when either the hydrogen concentration measured by the hydrogen concentration sensor exceeding a hydrogen concentration threshold or the oxygen concentration measured by the oxygen sensor falling below an oxygen concentration threshold.
    Type: Grant
    Filed: July 14, 2004
    Date of Patent: November 29, 2005
    Assignee: Ballard Power Systems Inc.
    Inventors: Jake de Vaal, Harvindra Deo
  • Patent number: 6960401
    Abstract: A purge system for fuel cell stack includes a purge valve to regulate exhaust from the fuel cell stack in response control signals from a controller in response to a voltage across a purge cell portion of a fuel cell stack. The purge valve is opened when the voltage across the purge cell portion falls below a defined percentage of a threshold voltage. The threshold voltage can be equal to an average cell voltage of some or all of the fuel cells of the fuel cell stack. The purge may include one or more successive openings of the purge valve of controlled purge durations.
    Type: Grant
    Filed: July 25, 2001
    Date of Patent: November 1, 2005
    Assignee: Ballard Power Systems Inc.
    Inventors: Russell Howard Barton, Tan Duc Uong, Charles Joseph Schembri, George Alexander Skinner
  • Patent number: 6953630
    Abstract: A respective bipolar junction transistor is coupled across pairs of fuel cells in a fuel cell stack to monitor the voltage across each fuel cell pairs for a drop in voltage below a threshold voltage. A respective optoisolator coupled to each of the transistors produces a digital signal corresponding to the status of the respective pair of fuel cells. An “AND” circuit produces a single digital signal corresponding to the status of one or more pairs of fuel cells.
    Type: Grant
    Filed: July 25, 2001
    Date of Patent: October 11, 2005
    Assignee: Ballard Power Systems Inc.
    Inventor: Brian Wells
  • Patent number: 6946212
    Abstract: An electrochemical fuel cell stack with improved reactant manifolding and sealing includes a pair of separator plates interposed between adjacent membrane electrode assemblies. Passageways fluidly interconnecting the anodes to a fuel manifold and interconnecting the cathodes to an oxidant manifold are formed between adjoining non-active surfaces of the pairs of separator plates. The passageways extend through one or more ports penetrating the thickness of one of the plates thereby fluidly connecting the manifold to the opposite active surface of that plate, and the contacted electrode. The non-active surfaces of adjoining separator plates in a fuel cell stack cooperate to provide passageways for directing both reactants from respective stack fuel and oxidant supply manifolds to the appropriate electrodes. The fuel and oxidant reactant streams passageways are fluidly isolated from each other, although they both traverse adjoining non-active surfaces of the same pair of plates.
    Type: Grant
    Filed: June 15, 2004
    Date of Patent: September 20, 2005
    Assignee: Ballard Power Systems Inc.
    Inventors: Joel A. Ronne, Boguslaw M. Wozniczka, Clarence Y. Chow, Henry H. Voss
  • Patent number: 6936370
    Abstract: In a solid polymer fuel cell series, various circumstances can result in the fuel cell being driven into voltage reversal. For instance, cell voltage reversal can occur if that cell receives an inadequate supply of fuel (for example, fuel starvation). In order to pass current during fuel starvation, reactions other than fuel oxidation may take place at the fuel cell anode, including water electrolysis and oxidation of anode components. The latter may result in significant degradation of the anode. Such fuel cells can be made more tolerant to cell reversal by promoting water electrolysis over anode component oxidation at the anode. This can be accomplished by incorporating a catalyst composition at the anode to promote the water electrolysis reaction, in addition to the typical anode electrocatalyst for promoting fuel oxidation.
    Type: Grant
    Filed: August 22, 2000
    Date of Patent: August 30, 2005
    Assignees: Ballard Power Systems Inc., Johnson Matthey Public Limited Company
    Inventors: Shanna D. Knights, David P. Wilkinson, Stephen A. Campbell, Jared L. Taylor, John M. Gascoyne, Thomas R. Ralph
  • Patent number: 6926981
    Abstract: In the present fuel cell systems, fuel cell stacks operate on a fuel stream having a pressure that is below the pressure of the surrounding environment, for example below atmospheric pressure. In the event of a leak, the fuel stream will not escape to the surrounding atmosphere, but rather gases from the surrounding environment will leak into the fuel stream. The fuel stream generally cannot exit the fuel cell stack during normal operation. The fuel cell stack may be periodically purged by increasing the pressure of the fuel stream above the pressure of the surrounding environment and by permitting exit through the fuel stream outlet. A monitoring device can be employed to determine when to purge the fuel cell stack.
    Type: Grant
    Filed: November 27, 2002
    Date of Patent: August 9, 2005
    Assignee: Ballard Power Systems Inc.
    Inventor: Henry Voss
  • Patent number: 6924057
    Abstract: In an improved electrochemical fuel cell assembly, a reactant flow path extends substantially linearly across the electrochemically active area of an electrode. The electrode has an in-plane nonuniform structure in its electrochemically active area as the active area is traversed in the direction of the substantially linear reactant flow path. Embodiments in which the structure of the fuel cell electrode varies substantially symmetrically along the reactant flow path are particularly preferred in fuel cells in which the flow direction of a reactant is periodically reversed.
    Type: Grant
    Filed: February 8, 2002
    Date of Patent: August 2, 2005
    Assignee: Ballard Power Systems Inc.
    Inventors: David P. Wilkinson, Peter R. Gibb
  • Patent number: 6913847
    Abstract: An electric power generating system is provided that comprises a fuel cell stack having at least one solid polymer fuel cell, a cooling system having a coolant flow path that directs coolant to and from the stack, a fuel regulating system having a fuel flow path and for regulating the supply of fuel from a fuel supply to the stack via the fuel flow path, and a hydrogen concentration sensor. The sensor is located in the vicinity of the fuel regulating system and in the coolant flow path at a location downstream of the stack to detect hydrogen that may have been discharged by components of the power generating system in the coolant flow path upstream of the sensor, or by the fuel regulating system. In the event the measured hydrogen concentration exceeds a threshold level, steps are taken to reduce or stop the discharge of hydrogen from the power generating system.
    Type: Grant
    Filed: July 25, 2001
    Date of Patent: July 5, 2005
    Assignee: Ballard Power Systems Inc.
    Inventors: Brian Wells, Kenneth W. Strang
  • Publication number: 20050136301
    Abstract: Radio frequency identification (RFID) devices may be used to monitor various operating parameters in fuel cells. For example, RFID devices may be used to monitor the voltage of individual cells in a fuel cell stack and thus to check for voltage reversal conditions during stack operation.
    Type: Application
    Filed: December 19, 2003
    Publication date: June 23, 2005
    Applicant: Ballard Power Systems Inc.
    Inventors: Leslie Knaggs, Fariborz Ordubadi, Edwin Vink
  • Publication number: 20050136314
    Abstract: A membrane electrode assembly has two gas diffusion layers, two catalyst layers and an ion-exchange membrane interposed therebetween wherein the ion-exchange membrane is cast from a sulphonated polyether ketone/sulfone ionomer. Specifically, the ionomer can be represented as A-B-C wherein Further x, y, z represent the mole ratios of each moiety in the ionomer such that x is between 0.25 and 0.40; y is between 0.01 and 0.26; and z is between 0.40 and 0.67. Melt viscosity of the corresponding base polymer also affects performance in the fuel cell, particularly at values over 0.4 kNsm?2 as measured at 400° C., 1000 s?1. In preparing the membrane electrode assembly, the catalyst layers may be coated directly on the membrane and then bonded with two gas diffusion layers.
    Type: Application
    Filed: December 17, 2003
    Publication date: June 23, 2005
    Applicant: Ballard Power Systems Inc.
    Inventors: Charles Stone, Cindy Mah, Paul Meharg, Sean MacKinnon, Scott McDermid, Stephen Hamada, Miho Hall
  • Publication number: 20050136308
    Abstract: A significant problem in PEM fuel cell durability is in premature failure of the ion-exchange membrane and in particular by the degradation of the ion-exchange membrane by reactive hydrogen peroxide species. Such degradation can be reduced or eliminated by the presence of an additive in the anode, cathode or ion-exchange membrane. The additive may be a radical scavenger, a membrane cross-linker, a hydrogen peroxide decomposition catalyst and/or a hydrogen peroxide stabilizer. The presence of the additive in the membrane electrode assembly (MEA) may however result in reduced performance of the PEM fuel cell. Accordingly, it may be desirable to restrict the location of the additive to locations of increased susceptibility to membrane degradation such as the inlet and/or outlet regions of the MEA.
    Type: Application
    Filed: December 17, 2003
    Publication date: June 23, 2005
    Applicant: Ballard Power Systems Inc.
    Inventors: Neil Andrews, Shanna Knights, Kenneth Murray, Scott McDermid, Sean MacKinnon, Siyu Ye
  • Publication number: 20050129988
    Abstract: An electrochemical fuel cell stack comprises a plurality of fuel cell assemblies, wherein, each fuel cell assembly comprises a cell compressed between a pair of flow field plates, a perimeter seal circumscribing the cell and interposed between the pair of flow field plates, and a first diode, having an aspect ratio greater than 10:1, positioned adjacent to, and outside of, the perimeter seal along a first edge of the cell and interposed between the pair of flow field plates.
    Type: Application
    Filed: December 16, 2003
    Publication date: June 16, 2005
    Applicant: Ballard Power Systems Inc.
    Inventors: Shanna Knights, Jacob De Vaal, Michael Lauritzen, David Wilkinson
  • Patent number: 6896982
    Abstract: Certain fuel cells (e.g., solid polymer electrolyte fuel cells) may temporarily exhibit below normal performance after initial manufacture or after prolonged storage. While normal performance levels may be obtained after operating such fuel cells for a suitable time period, this process can take of order of days to fully complete. However, exposing the cathode to a reductant (e.g., hydrogen) can provide for normal performance levels without the need for a lengthy initial operating period.
    Type: Grant
    Filed: May 30, 2002
    Date of Patent: May 24, 2005
    Assignee: Ballard Power Systems Inc.
    Inventors: Nengyou Jia, Benno Giesecke
  • Patent number: 6896792
    Abstract: The activity of catalysts used in promoting the oxidation of certain oxidizable species in fluids can be enhanced via electrochemical methods, e.g., NEMCA. In particular, the activity of catalysts used in the selective oxidation of carbon monoxide can be enhanced. A purification system that exploits this effect is useful in purifying reformate supplied as fuel to a solid polymer electrolyte fuel cell stack. The purification system comprises an electrolytic cell with fluid diffusion electrodes. The activity of catalyst incorporated in the cell anode is enhanced.
    Type: Grant
    Filed: June 11, 2002
    Date of Patent: May 24, 2005
    Assignee: Ballard Power Systems Inc.
    Inventors: Jean St-Pierre, David P. Wilkinson, Stephen A. Campbell
  • Patent number: 6887606
    Abstract: A controller in a fuel cell system performs various operating parameter checks at a predefined schedule, including one or more of a stack current check; a stack voltage check; a cell voltage check; a purge cell check; an oxygen concentration check; a hydrogen concentration check; a stack temperature check; an ambient air temperature check; a fuel pressure check; and an airflow rate check; a hydrogen sensor heater check; a battery voltage check; a microcontroller self-check; and/or toggling a watchdog. The frequency of the checks are set relative to achieve an efficient control of the fuel cell system by selectively distributing the load on the microcontroller.
    Type: Grant
    Filed: July 25, 2001
    Date of Patent: May 3, 2005
    Assignee: Ballard Power Systems Inc.
    Inventors: Robert Kenneth Parr, Brian Wells
  • Publication number: 20050089746
    Abstract: Contamination of the ion-exchange membrane in an electrochemical fuel cell can significantly reduce the lifetime. One source of contamination is from sealant materials, particularly if the sealant is silicone and impregnated into the peripheral region of the membrane electrode assembly (MEA) and thus in close proximity to the ion-exchange membrane. Contamination may be reduced or eliminated by separating the electrochemical reaction and/or the ion-exchange membrane from the sealant material. In an embodiment, this is done by having the sealing region substantially free of active electrocatalyst particles (for example, selectively printing the catalyst to avoid the sealing region or poisoning catalyst in the sealing region). In another embodiment, a barrier film is interposed between the ion-exchange membrane and the sealant material impregnated into the MEA. In yet another embodiment, a barrier plug is impregnated into the fluid diffusion layer adjacent to the sealant material impregnated into the MEA.
    Type: Application
    Filed: October 23, 2003
    Publication date: April 28, 2005
    Applicant: Ballard Power Systems Inc.
    Inventors: Gregory James, Sean MacKinnon, Duarte Sousa, David Summers, Warren Williams, Julie Bellerive, Myles Bos, Robert Rempel, Simon Farrington, Scott McDermid
  • Patent number: 6874352
    Abstract: A method for locating a fluid leak in a fuel cell stack is disclosed. The method comprises pressurizing a first fluid stream passage with a tracer fluid, introducing a flow fluid to a second fluid stream passage, maintaining a substantially constant flow of the flow fluid through the second fluid stream passage toward an exit point of the fuel cell stack, inserting a probe, adapted to monitor for the presence of the tracer fluid in the flow fluid, into the exit point, moving the probe through the second fluid stream passage and monitoring for the presence of the tracer fluid in the flow fluid at various locations of the second fluid stream passage. An apparatus for locating a fluid leak in a fuel cell stack is also provided.
    Type: Grant
    Filed: January 9, 2004
    Date of Patent: April 5, 2005
    Assignee: Ballard Power Systems Inc.
    Inventors: Zhaoyu Wang, Stephan Lutz, Karl D. Inglehart
  • Publication number: 20050064255
    Abstract: An electric power generation system has a multiple jet ejector assembly for recirculating an exhaust stream. The system includes a fuel cell stack having a reactant stream inlet, a reactant stream outlet and at least one fuel cell. A pressurized reactant supply provides a reactant to the multiple jet ejector assembly. The multiple jet ejector assembly includes two motive flow inlets, one suction inlet, fluidly connected to the reactant stream outlet to receive a recirculated flow from the fuel cell stack, and one discharge outlet, fluidly connected to the reactant stream inlet to provide an inlet stream to the fuel cell stack. A pressure regulator is interposed between the pressurized reactant supply and the two motive flow inlets of the multiple jet ejector assembly. A first solenoid valve is interposed between the first motive flow inlet and the regulator. A second solenoid valve is interposed between the second motive flow inlet and the regulator.
    Type: Application
    Filed: September 18, 2003
    Publication date: March 24, 2005
    Applicant: Ballard Power Systems Inc.
    Inventors: Janusz Blaszczyk, Rainer Schmidt, Wolfram Fleck, Paul Paterson