Patents Assigned to Ballard Power Systems Inc.
  • Patent number: 7300984
    Abstract: A process for preparing a graft copolymers is provided comprising exposing a polymeric base material to a dose of ionizing radiation, and then contacting the irradiated base material with a microemulsion comprising at least one fluorostyrenic monomer, water and water-miscible solvent. The graft copolymer may be formed into a membrane, including ion exchange membranes.
    Type: Grant
    Filed: November 3, 2004
    Date of Patent: November 27, 2007
    Assignee: Ballard Power Systems Inc.
    Inventor: Sean M MacKinnon
  • Patent number: 7235315
    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: Grant
    Filed: December 16, 2003
    Date of Patent: June 26, 2007
    Assignee: Ballard Power Systems Inc.
    Inventors: Shanna D Knights, Jacob W De Vaal, Michael V Lauritzen, David P Wilkinson
  • Patent number: 7226689
    Abstract: A membrane electrode assembly may be made using a one-sided catalyst coated membrane (CCM) wherein only one catalyst layer, either the anode or the cathode, is coated directly on the ion-exchange membrane. In particular, a one-sided CCM may be used where it may not be practicable to coat both sides of the ion-exchange membrane with catalyst layers such as when PTFE is added to the anode catalyst layer to render it reversal tolerant.
    Type: Grant
    Filed: June 20, 2003
    Date of Patent: June 5, 2007
    Assignee: Ballard Power Systems Inc.
    Inventors: Siyu Ye, Paul Beattie, Todd E Wilke, Shannon R Hodgson, Kyoung Bai, Michael V Lauritzen
  • Patent number: 7169490
    Abstract: In a hydrogen gas line where the composition of the gas is primarily hydrogen, impurities present in the gas line will typically reduce the speed of sound. Accordingly, an acoustic sensor can be used in such a hydrogen gas line to indicate when impurities have accumulated in the gas line. In particular, the hydrogen gas line may be in a fuel line for an electrochemical fuel cell system. The sensor may comprise transducers, more particularly piezoelectric transducers, as both sound detectors and/or sound generators. Further, the sensor can measure either the speed or frequency of sound to determine the hydrogen concentration. If the fuel is recirculated back to the anode inlet, such a hydrogen sensor in the anode exhaust may be used to determine when it is beneficial to purge the anode exhaust to the external atmosphere.
    Type: Grant
    Filed: March 29, 2004
    Date of Patent: January 30, 2007
    Assignee: Ballard Power Systems Inc.
    Inventors: Russell H Barton, Michael P Sexsmith
  • Patent number: 7160640
    Abstract: A fuel cell system comprising a passive end cell heater for heating an end cell or cells within a fuel cell stack is disclosed. The fuel cell system comprises a fuel cell stack and a resistive heatable element connected in parallel to the fuel cell stack, wherein the resistive heatable element is adapted to heat an end cell of the fuel cell stack. A method for heating an end cell in a fuel cell stack is also disclosed.
    Type: Grant
    Filed: January 15, 2003
    Date of Patent: January 9, 2007
    Assignee: Ballard Power Systems Inc.
    Inventor: Steven E. Houlberg
  • Patent number: 7153598
    Abstract: A fuel cell system is operated with the fuel supply pressure greater than the oxidant supply pressure to the fuel cell. This gives improved performance particularly when the fuel cell system is closed on the fuel side. The magnitude of fuel overpressure may be varied in accordance with variations in the fuel cell operating parameters.
    Type: Grant
    Filed: March 5, 2004
    Date of Patent: December 26, 2006
    Assignee: Ballard Power Systems Inc.
    Inventors: David A. Summers, Herwig R. Haas
  • Patent number: 7144646
    Abstract: A fuel cell system determines each of a battery charging current error, a battery voltage error, and a stack current error. The fuel cell system regulates current through a series pass element in response to a greater of the determined errors. Thus, the fuel cell system operates in three modes: battery voltage limiting mode, stack current limiting mode and battery charging current limiting mode. Additionally, there can be a fourth “saturation” mode where the stack voltage VS drops below the battery voltage VB as the load pulls even more current. Individual fuel cell systems can be combined in series and/or parallel to produce a combined fuel cell system having a desired output voltage and current.
    Type: Grant
    Filed: December 14, 2001
    Date of Patent: December 5, 2006
    Assignee: Ballard Power Systems Inc.
    Inventor: Martin T. Pearson
  • Patent number: 7132179
    Abstract: Apparatus and methods of ceasing operation of an electric power generating system improve the cold starting capability of the system. The system comprises a fuel cell stack connectable to an external circuit for supplying power to the external circuit. The stack comprises at least one solid polymer fuel cell, and the system further comprises a fuel passage for directing a fuel stream through the stack and an oxidant passage for directing an oxidant stream through the stack, a sensor assembly connected to the stack for monitoring a parameter indicative of stack performance, a controller for controlling at least one stack operating parameter, and a control system communicative with the sensor assembly and stack operating parameter controller.
    Type: Grant
    Filed: March 28, 2002
    Date of Patent: November 7, 2006
    Assignee: Ballard Power Systems Inc.
    Inventors: Jean St-Pierre, NengYou Jia, Marian Van Der Geest, Abderrahmane Atbi, Herwig R. Haas
  • Patent number: 7132185
    Abstract: A fuel cell system for powering a work load includes a fuel cell stack and a shunt regulator having a threshold detection; transistorized power switching element, and a dump load. The threshold detection element identifies when an abnormally high voltage rises. The power switching element routes power from the high voltage buss to the dump load. The dump load acts as an electrical energy sink, and may provide dissipated energy to the fuel cell stack in the form of heat. The switching element can also shunt power to the dump load when a digital control signal is set, for example at startup or during cold start conditions.
    Type: Grant
    Filed: December 14, 2001
    Date of Patent: November 7, 2006
    Assignee: Ballard Power Systems Inc.
    Inventors: David S. Wardrop, Michael Sexsmith, Russell H. Barton
  • Patent number: 7125820
    Abstract: Non-noble metal transition metal catalysts can replace platinum in the oxidation reduction reaction (ORR) used in electrochemical fuel cells. A RuxSe catalyst is prepared with comparable catalytic activity to platinum. An environmentally friendly aqueous synthetic pathway to this catalyst is also presented. Using the same aqueous methodology, ORR catalysts can be prepared where Ru is replaced by Mo, Fe, Co, Cr, Ni and/or W. Similarly Se can be replaced by S.
    Type: Grant
    Filed: July 29, 2003
    Date of Patent: October 24, 2006
    Assignee: Ballard Power Systems Inc.
    Inventor: Stephen A Campbell
  • Patent number: 7087327
    Abstract: An electric power plant includes an array of fuel cell systems. The fuel cell systems are electrically couplable in series and/or parallel combinations to provide a variety of output powers, output current and/or output voltages. The fuel cell systems are “hot swappable” and redundant fuel cell systems may automatically replace faulty fuel cell systems to maintain output power, current and/or voltage.
    Type: Grant
    Filed: May 16, 2003
    Date of Patent: August 8, 2006
    Assignee: Ballard Power Systems Inc.
    Inventor: Martin T. Pearson
  • Patent number: 7078117
    Abstract: A membrane exchange humidifier employs a water permeable membrane comprising a microporous polymer and a hydrophilic additive. In operation, the membrane preferably has favorable water transmission properties and resists transmission of reactant gas or other components. The membrane is suitable for use even when permeable in its dry condition to the wet or dry gases in the humidifier, and/or when the wet and dry gases are of different composition. By wetting the membrane, the presence of an amount of liquid water in the wet gas can reduce gas transmission through the membrane to an acceptable level. The humidifier is useful in fuel cell systems in which a reactant gas supply stream, such as the oxidant supply stream, is humidified primarily using water vapor from a fuel cell reactant exhaust stream. The humidifier is particularly suitable for use in conjunction with solid polymer fuel cell systems. The improved mechanical and welding properties of the membrane allow for a simpler humidifier configuration.
    Type: Grant
    Filed: February 2, 2005
    Date of Patent: July 18, 2006
    Assignee: Ballard Power Systems Inc.
    Inventor: Alexander D Mossman
  • Patent number: 7070876
    Abstract: A membrane electrode assembly with an improved integrated seal comprises an edge seal having an inboard pad attached to the edge of the electrodes, a flexible coupling adjacent the pad, and a sealing element adjacent the coupling. The sealing element is significantly thicker than the pad, and the flexible coupling isolates the pad from stress experienced in the sealing element. Thus, greater compression can be applied to the sealing element, thereby providing an improved and more reliable seal, without overly compressing and damaging the attached pad.
    Type: Grant
    Filed: March 24, 2003
    Date of Patent: July 4, 2006
    Assignee: Ballard Power Systems, Inc.
    Inventors: Robert H. Artibise, Simon Farrington
  • Patent number: 7060166
    Abstract: An aqueous ionomer gel having a high viscosity, particularly a proton conducting ionomer, as well as to related products incorporating such gels. Such aqueous ionomer gels are suitable for suspending catalysts for formation of catalyst inks, which in turn are suitable for screen printing on a variety of surfaces. Representative surfaces are the electrode or membrane surfaces in an electrochemical fuel cell. Methods for making aqueous ionomer gels are also disclosed.
    Type: Grant
    Filed: November 12, 2003
    Date of Patent: June 13, 2006
    Assignee: Ballard Power Systems Inc.
    Inventors: Wesley Gervais, Michael V Lauritzen, Kristi M Zychowka, Lawrence A Vanderark, Kevin Michael Colbow
  • Patent number: 7041404
    Abstract: In a liquid feed fuel cell system, substantially pure fuel needs to be added to a dilute mixture of fuel in water so as to maintain the fuel concentration at an appropriate level for use with the fuel cell system. Under passive control of the fuel concentration, a first equilibrium concentration is established between the substantially pure fuel and a fuel transfer medium. A second equilibrium concentration is then established between the fuel transfer medium and the dilute mixture for use with the fuel cell system. The system is “passive” as it does not rely on the measurement of the fuel concentration and direct injection of fuel. The fuel transfer medium can be solid, liquid or gas.
    Type: Grant
    Filed: June 27, 2003
    Date of Patent: May 9, 2006
    Assignee: Ballard Power Systems Inc.
    Inventor: Joerg Zimmermann
  • Patent number: 7022427
    Abstract: The invention relates to an ion-conductive polymer membrane for a fuel cell, whereby the polymer membrane is configured from a polymer-forming hydrocarbon material and to a method for producing the same. The membrane also has a metal-containing gel which has been hydrolysed and/or condensed from a metal alkoxide starting material and which is deposited in the polymer and/or is chemically bonded to the polymer. The proportion of metal alkoxide by weight, in relation to the membrane, lies between 25% and 1%.
    Type: Grant
    Filed: August 30, 2000
    Date of Patent: April 4, 2006
    Assignee: Ballard Power Systems Inc.
    Inventors: Hubertus Biegert, Peter Britz, Gabor Toth, Peter Urban
  • Patent number: 7014935
    Abstract: A solid polymer electrolyte fuel cell stack having a plurality of fuel cells, wherein at least one cell of the fuel cell stack has a resistance to corrosion that is greater than a significant portion of the other fuel cells of the stack. In one embodiment, the at least one fuel cell of the fuel cell stack that is more resistant to corrosion is one or both end cells of the stack. Also disclosed is a fuel cell system containing such a stack, as well as methods for reducing degradation of the same during operation.
    Type: Grant
    Filed: April 11, 2003
    Date of Patent: March 21, 2006
    Assignee: Ballard Power Systems Inc.
    Inventors: Shanna D. Knights, David P. Wilkinson
  • Patent number: 7011902
    Abstract: A black start operation employs the accumulation of power resulting from a reaction of fuel and ambient oxidant passively seeped or diffused into a fuel cell stack to bootstrap the fuel cell system operation.
    Type: Grant
    Filed: March 12, 2003
    Date of Patent: March 14, 2006
    Assignee: Ballard Power Systems Inc.
    Inventor: Martin T. Pearson
  • Patent number: 6997696
    Abstract: In a method and apparatus for cutting expanded graphite sheet material, at least one cutting tool is urged against the sheet(s). The cutting tool has at least one ridge extending therefrom that includes a substantially tapered cross-section having sloping sides and an edge surface. At least a portion of the sheet material is displaced as the ridge is urged against the sheet. A region of the sheet material in contact with the ridge is compressed so that the density of the region reaches or exceeds the breaking density of the sheet.
    Type: Grant
    Filed: May 21, 2003
    Date of Patent: February 14, 2006
    Assignee: Ballard Power Systems Inc.
    Inventors: Neil V. Davis, David Brown
  • Patent number: 6989213
    Abstract: The invention relates to a metal bipolar plate for a fuel cell, provided with a low-ohmic chemically stable coating. According to the invention, said coating is a multi-phase coating, at least in the region of the contacting outer surface thereof. One phase is a metal phase and/or ? phase belonging thereto and another phase is a compound phase consisting of one or several metals of the metal phase and one of the elements N,O,C,B.
    Type: Grant
    Filed: April 6, 2001
    Date of Patent: January 24, 2006
    Assignee: Ballard Power Systems Inc.
    Inventors: Wolfram Kaiser, Detlev Repenning, Richard Spaeh, Joerg Wind