Abstract: Methods and apparatus are disclosed for impregnating a resiliently compressible, porous substrate with a material by: compressing the substrate through a calendering apparatus; contacting the compressed substrate with a fluid comprising the material; maintaining the calendered substrate in contact with the fluid while the calendered substrate expands, thereby impregnating the substrate with the material; and drying the impregnated substrate. Such impregnated substrates find particular application as gas diffusion layers for anodes and cathodes used in fuel cells.
Abstract: A fuel cell system has a fuel cell unit with at least one fuel cell and a gas generation system, which supplies the fuel cell unit with hydrogen from an operating medium, and at least one ion exchanger unit for removing ions from water. The at least one ion exchanger unit is arranged in a flow path for the operating medium, between a condensate separator and the gas generation system and is acted on by a mixture of water and the operating medium.
Abstract: Voltage reversal in fuel cell stacks may be detected and/or prevented by monitoring each cell or small groups of cells in the stack for low voltage conditions. An improved cell voltage monitor is constructed using a plurality of voltage monitoring units in which each unit comprises a heating resistor, a rectifier in series therewith, and a sensing thermistor in thermal communication with the heating resistor. The heating resistor is electrically-connected across a cell or cells and heats the associated sensing thermistor in accordance with the voltage of the cell(s). Since the resistance of the sensing thermistor is indicative of its temperature and hence also of voltage of the cell(s), the sensing thermistor resistance can be used to signal a low voltage condition.
Abstract: Graft polymeric membranes and methods for making graft polymeric membranes have one or more trifluorovinyl aromatic monomers that are radiation graft polymerized to a polymeric base film. The membranes comprise a polymeric base film to which has been graft polymerized substituted &agr;,&agr;,&bgr;-trifluorostyrene and/or &agr;,&agr;,&bgr;-trifluorovinylnaphthylene monomers, which are activated towards graft polymerization. As ion-exchange membranes, the membranes are suitable for use in electrode apparatus, including membrane electrode assemblies in, for example, fuel cells. The membranes can also be crosslinked.
Type:
Grant
Filed:
August 21, 2001
Date of Patent:
April 20, 2004
Assignee:
Ballard Power Systems Inc.
Inventors:
Charles Stone, Alfred E. Steck, Biswajit Choudhury
Abstract: An ion-exchange membrane may be continuously coated by depositing a catalyst composition on a release surface, drying the catalyst at an elevated temperature and then transferring the dried catalyst layer onto an ion-exchange membrane by applying pressure at a different elevated temperature. Also disclosed is an apparatus for thus continuously coating an ion-exchange membrane. The catalyst coated membrane is of particular use in polymer electrolyte membrane (PEM) fuel cells for which a membrane electrode assembly may be prepared by bonding fluid distribution layers to the catalyst coated membrane.
Type:
Application
Filed:
October 9, 2002
Publication date:
April 15, 2004
Applicant:
Ballard Power Systems Inc.
Inventors:
Haijiang Wang, Guy Ebbrell, Evelyn Lai, Steven Mallinson, Gianni Fiorini, Silvia Wessel
Abstract: Regulation of energy supplied to an electric motor from an energy supply system comprising a fuel cell and an energy storage buffer such as a battery, improves the dynamic response of the motor by adding current from the energy storage buffer to the current from the fuel cell during acceleration.
Type:
Application
Filed:
May 23, 2003
Publication date:
April 8, 2004
Applicant:
Ballard Power Systems AG
Inventors:
Markus Aberle, Joachim Blum, Mathias Boehmisch, Thomas Schetter
Abstract: An elastomer may be used to construct a separate, moldable part that engages the edge a membrane electrode assembly (MEA) to thereby seal the MEA. The seal has a groove defining two sealing portions separated by a web portion. The groove of the seal then engages the edge of the MEA and can maintain a tight fit without the need for additional adhesives. Additional features may extend laterally from the web portion to assist in separating cathode and anode plates and/or encompass, for example, manifold openings.
Abstract: In a method of manufacturing a fluid diffusion layer for a solid polymer electrolyte fuel cell, a surface of the fluid diffusion layer is abraded so that the topography of the fluid diffusion layer surface is rendered more uniform. The fluid diffusion layer comprises a porous substrate, and may also comprise a carbon-containing sublayer, as well as hydrophobic material. The particles formed by the abrading operation may be deposited into at least some of the pores of the substrate to form a support structure for the direct depositing of a catalyst onto the abraded surface.
Type:
Grant
Filed:
May 2, 2001
Date of Patent:
April 6, 2004
Assignee:
Ballard Power Systems Inc.
Inventors:
Volker Peinecke, Jorg von der Osten-Fabeck, John Robert Gordon, Herwig Robert Haas
Abstract: A power system, such as an integrated power module comprising a bi-directional converter, functionally combines a power inverter and a charger such as a charger for charging one or more electrical storage devices such as batteries and/or super- or ultra-capacitors. A first switch selectively couples one or more AC devices to the bi-directional converter, and/or a second switch selectively couples a boosting circuit to one or more DC devices and/or reverses polarity of the coupling. The power system may have electric vehicle and/or vehicle-to-grid applications.
Abstract: The present methods make fluid diffusion layers having reduced surface roughness. The methods used for adhering the loading material to the substrate surface can reduce the average surface roughness of the fluid diffusion layers, thereby reducing leaks in and damage to ion exchange membranes. When fluid diffusion layers and electrodes having reduced surface roughness are employed in membrane electrode assemblies, better reliability and performance are obtained. A method of calculating the surface roughness of a fluid diffusion layer may be used.
Type:
Grant
Filed:
May 16, 2001
Date of Patent:
March 30, 2004
Assignee:
Ballard Power Systems Inc.
Inventors:
Jürgen Stumper, John Robert Gordon, Herwig Robert Haas, Kelvin Keen-Ven Fong
Abstract: A multifuel fuel cell system includes a hydrogen production unit; at least one fuel cell; means for heating a first catalytic converter element in the hydrogen production unit to an operating temperature which can be preset; means for metering liquid fuel, air, and optionally water to the catalytic converter element to produce a synthetic gas mixture containing hydrogen or a reformate; and means for passing the synthetic gas or reformate to further components of the hydrogen production unit which are connected between the catalytic converter element and the at least one fuel cell. The fuel cell system also contains means for switching the fuel cell system between a first and a second operating mode.
Type:
Grant
Filed:
March 2, 2001
Date of Patent:
March 30, 2004
Assignee:
Ballard Power Systems AG
Inventors:
Marcel Corneille, Martina Fischer, Berthold Keppeler, Christian Lorenz, Stefan Paulik, Bernd Schönrock
Abstract: The present invention relates to a system and method for compensating the voltage distortion and minimizing the available voltage range loss both caused by switching dead-time of solid-state switch components in power conversion devices. As a result, the power quality supplied from the power conversion devices can be improved and the output voltage of such devices can be increased.
Type:
Grant
Filed:
November 27, 2002
Date of Patent:
March 30, 2004
Assignee:
Ballard Power Systems Corporation
Inventors:
Doug D. Deng, Kon-King M. Wang, Steven J. Kowalec
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.
Abstract: Water management is improved in solid polymer electrolyte fuel cells by employing capillary channels or wicks in the lands that separate the reactant distribution channels in the flow fields. Capillary action moves water within these micro-sized capillary channels or wicks. Appropriate designs can be used to assist in the removal of water from the cell and/or in the redistribution of water from relatively wet regions in the cell to relatively dry regions.
Type:
Application
Filed:
September 20, 2002
Publication date:
March 25, 2004
Applicant:
Ballard Power Systems Inc.
Inventors:
Abderrahmane Atbi, David P. Wilkinson, Olen R. Vanderleeden, Shanna D. Knights, Andrew Lew
Abstract: Fuel cells are disclosed that operate directly on fuel streams comprising tetramethyl orthocarbonate in which tetramethyl orthocarbonate is directly oxidized at the anode and, more particularly, to solid polymer fuel cells operating directly on liquid fuel streams comprising tetramethyl orthocarbonate. Also disclosed are methods relating thereto.
Abstract: System and method for enhancing the torque output of a field oriented induction motor including a controller having a plurality of predetermined control parameters operable for processing input signals to generate output signals. The plurality of predetermined control parameters are dependent upon the nature of the input signals and the operational state of the motor. A sensor system is operable for communicating feedback signals related to the output signals and the operational state of the motor from the motor to the controller.
Type:
Grant
Filed:
November 13, 2001
Date of Patent:
March 16, 2004
Assignee:
Ballard Power Systems Corporation
Inventors:
Li Chen, Kerry Eden Grand, Richard Joseph Hampo, Vinod Reddy, Xingyi Xu, Nick Langovsky
Abstract: A fuel cell includes at least one cell that contains a proton-conducting polymer electrolyte membrane, which separates an anode compartment and a cathode compartment. The membrane is comprised of a thermoplastic polymer that has a permanent service temperature of at least 100° C.
Type:
Grant
Filed:
April 8, 2002
Date of Patent:
March 16, 2004
Assignee:
Ballard Power Systems, Inc.
Inventors:
Hubertus Biegert, Peter Britz, Arnold Lamm, Gabor Toth, Peter Urban
Abstract: A device inserted between a grounded poly-phase external voltage source and a load providing low insertion loss for differential mode currents and high insertion loss for ground currents. The device receives voltages from the grounded poly-phase external voltage source over atone or more voltage lines. The voltages contain common mode voltages. A filter connected to each of the voltage lines reduces the ground current from the load. A summing block adds the voltages from each of the voltage lines to generate a total common mode voltage. A ground referenced controlled voltage source generates a cancellation voltage equal to the total common mode voltage in response to the generation of total common mode voltage. The total common mode voltage is injected into the filter and substantially reduces the common mode voltage on each voltage line thereby substantially reducing the ground currents associated with each common mode voltage on each voltage line.
Abstract: The electrochemical performance of an ion-exchange membrane in a fuel cell system may be improved by impregnating therein a perfluoroamine. The amine may be primary, secondary or tertiary. Further, the amine is preferably water insoluble or only slightly water soluble. For example, the amine may be perfluorotriamylamine or perfluorotributylamine. Use of such a membrane system within a fuel cell may allow high or low temperature operation (i.e. at temperatures greater than 100° C. or less than 0° C.) as well as operation at low relative humidity.
Type:
Application
Filed:
August 28, 2002
Publication date:
March 4, 2004
Applicant:
Ballard Power Systems Inc.
Inventors:
David P. Wilkinson, Joy A. Roberts, Nengyou Jia, Eagranie Yuh, Shanna D. Knights, Jean St-Pierre
Abstract: In an operating liquid feed fuel cell system, fuel concentration in the fuel stream can be calculated as a function of the observed current, the temperature of the fuel stream entering the fuel cell stack, and the temperature of the fuel cell stack itself, thereby eliminating the need for a separate sensor. Typically, methanol will be used as the fuel and the liquid feed fuel cell system will thus be a direct methanol fuel cell system.
Type:
Grant
Filed:
December 19, 2001
Date of Patent:
March 2, 2004
Assignee:
Ballard Power Systems Inc.
Inventors:
Jiujun Zhang, Kevin M. Colbow, Alfred Wong, Bruce Lin