Gm Global Technolgoy Operations, Inc.

Michael W Murphy

Robert L Fuss

Lewis J DiPietro

Alan Jon Jacobsen

Jeffrey Allan Rock

Gerald W Fly

David H Chow

Glenn William Skala

Benno Andreas-Schott

Mark F Mathias

Leslie Momoda

Wenbin Gu

Robert S Foley

Brian A Litteer

Jennifer J Zinck

Balsu Lakshmanan

A current sensor assembly that monitors current flow through segments of a fuel cell stack. The current sensor assembly includes a first plate including a first non-conductive substrate having a first conductive path therethrough and that is in electrical communication with a first segment of the fuel cell stack. A second plate includes a second non-conductive substrate having a second conductive path therethrough and that is in electrical communication with a second segment of the fuel cell stack. A first current sensor is operably disposed between the first plate and the second plate and facilitates a first current flow between the first conductive path and the second conductive path. The first current sensor generates a first current signal based on the first current flow.

Integrated current sensors for a fuel cell stack

At least one positive temperature coefficient element is used to efficiently control fuel cell voltage at startup and shutdown making the fuel cell more efficient and protecting the electro catalyst layer.

PTC element as a self regulating start resistor for a fuel cell stack

A flow control valve for a fuel cell that has particular application for controlling the flow of cathode air through a cathode flow channel of the fuel cell. The valve includes an element that controls the flow through the flow channel in response to changes in the voltage potential of the fuel cell. The valve includes a shape memory alloy wire and a flow control element secured to both ends of the shape memory alloy wire. The ends of the wire are also coupled to the anode and cathode of the fuel cell. When no current is flowing through the wire, the flow control element holds the wire in a pre-strained condition. If the voltage generated by the fuel cell increases, the current passing through the wire will heat the wire and cause it to shrink or contract which forces the flow control element into the flow path.

Fuel cell control valve

A fuel cell system that employs a diode electrically coupled between bipolar plates in a fuel cell of a fuel cell stack for preventing the fuel cell between the plates from reversing its polarity. The diode is a thin-sheet p-n diode including doped semiconductor layers and has a thickness relative to the thickness of the MEA in the fuel cell so that the overall stack thickness does not increase. When the fuel cell is operating properly the diode does not conduct and all of the current through the fuel cell goes through the MEA. If the electric load on the stack increases to a level beyond the capability of the fuel cell, where the potential across the fuel cell goes significantly below zero, the diode will begin to conduct so that any current that cannot travel through the MEA with the cell voltage less than one negative forward diode voltage drop is able to go around the MEA through the diode.

Integration of an electrical diode within a fuel cell

The present invention is directed to an electrochemical fuel cell. The configuration of the fuel cell stack provides a multiple-legged current flow path therethrough. Electrically isolated zones are formed in the cells and one coupled in a serial manner. This configuration provides incremental voltage summing such that additional power converting element are not needed to match the stack output to the load.

Multi-zone voltage fuel cell

The present invention is directed to a planar flow field design having an intake manifold and an exhaust manifold which are configured in two offset planes. A relatively short passage extends from the intake manifold through the exhaust manifold and terminates at a reactive face of a membrane electrode assembly (MEA) such that a differential flow distribution is provided from the intake manifold through the passage and across a reactive face of the MEA to the exhaust manifold.

Ultra short high pressure gradient flow path flow field

A switch assembly for selectively enabling current flow through a segment of a fuel cell stack. The switch assembly includes a first plate including a first non-conductive substrate having a first conductive path therethrough and a second plate including a second non-conductive substrate having a second conductive path therethrough. A first switch is disposed between the first plate and the second plate and is in electrical communication with the first conductive path and the second conductive path. The first switch is operable in an open mode to prohibit current flow between the first conductive path and the second conductive path. The first switch is operable in a closed mode to enable current flow between the first conductive path and the second conductive path.

Integrated switching assemblies for a fuel cell stack

A method and system for detecting imperfections in a membrane electrode assembly of an electrochemical fuel cell, and more particularly for detecting defects within a proton exchange membrane in a membrane electrode assembly which is optionally sandwiched between conductive diffusion media layers or between conductive diffusion layers with at least one rigid solid that is transparent to infrared radiation. A potential voltage is applied across the membrane and the presence of a defect and preferably the location of a defect is determined by monitoring variations in intensity level of infrared radiation emitted from a surface of the membrane electrode assembly.

Method for detecting electrical defects in membrane electrode assemblies

A sensor plate for measuring current and/or temperature distribution of an operating fuel cell. The sensor plate has a circuit board interposed between an anode flow field plate and a cathode flow field plate of the fuel cell. A flow field plate is segmented into a plurality of electrically isolated regions without disrupting the flow field of the plate. The circuit board has an array of resistors and/or thermistors mounted to it wherein each resistor and/or thermistor is associated with one of the electrically isolated regions of the segmented plate. The current distribution of the electrically isolated regions of the fuel cell is calculated by using the voltage drop across the resistors and the known resistance values of the resistors mounted to the circuit board.

Growing community of inventors

Manchester, NY, United States of America

Michael W Murphy