Gm Global Technolgoy Operations, Inc.

Honda Motor Co., Ltd.

Pinkhas A Rapaport

Yeh-Hung Lai

Jeffrey Allan Rock

Thomas A Trabold

Steven R Falta

John P Salvador

Manish Sinha

Jon P Owejan

Thomas W Tighe

Hubert Gasteiger

Wenbin Gu

Michael D Cartwright

Po-Ya Abel Chuang

Andrew D Bosco

Lesley A Paine

Gayatri Vyas Dadheech

William Henry Pettit

Bruce Jeffrey Clingerman

Balasubramanian Lakshmanan

Abdullah Basar Alp

David S Mathews

Hiromichi Yoshida

Daniel J Darga

Daniel I Harris

Sriram Ganapathy

Eric L Thompson

Derek R Lebzelter

Eric J Connor

Jingxin Zhang

Lee Curtis Whitehead

Jason R Kolodziej

James A Leistra

Asao Uenodai

Reena L Datta

Matthew K Hortop

Swaminatha P Kumaraguru

John P Healy

Derek S Kilmer

Ivan Daryl Chapman

Shohei Toyota

Kim R Griffith

Nagappan Ramaswamy

Charles Mackintosh

Shyam Kocha

Amit Nayar

John C Fagey

Aaron J Blowers

A controller-executed method for conditioning a membrane electrode assembly (MEA) in a fuel cell for use in a fuel cell stack includes humidifying a fuel inlet to the stack to a threshold relative humidity level, and maintaining a current density and cell voltage of the fuel cell at a calibrated current density level and hold voltage level, respectively, via the controller in at least one voltage recovery stage. The recovery stage has a predetermined voltage recovery duration. The method includes measuring the cell voltage after completing the predetermined voltage recovery duration, and executing a control action with respect to the fuel cell or fuel cell stack responsive to the measured cell voltage exceeding a target voltage, including recording a diagnostic code via the controller indicative of successful conditioning of the MEA. A fuel cell system includes the fuel cell stack and controller.

System and method for MEA conditioning in a fuel cell

A fuel cell stack, a method of operating a fuel cell stack and a fuel cell system. In one particular form, shutting down the stack upon detection of a leakage of fuel either within the stack or from the stack involves depressurizing and uniform consumption of hydrogen by catalytic consumption in the cathode of all cells. Upon consumption of oxygen in the cathode portion of the stack by chemical reaction, the remaining unreacted nitrogen from the air acts as an inerting fluid. After an indication of reaction cessation is established, at least some of the inerting fluid is conveyed from the cathode portion to the anode portion. One or more of a bleed valve, backpressure valve and bypass valve are manipulated to promote the anode portion depressurization, cathode portion inerting and subsequent conveyance of the inerting fluid to the stack anode portion.

Shutdown method of fuel cell stack and fuel cell system therefor

A fuel cell stack includes a plurality of cell groups and a controller wherein each cell group comprises a plurality of fuel cells and a group sensor which measures one or more electrical characteristics of the respective cell group. The controller comprises one or more processors and memory and is communicatively coupled to each group sensor. The one or more processors execute machine readable instructions to compare a measured electrical characteristic of each cell group to one or more thresholds stored in memory, and indicate the need for diagnostics of the fuel cell stack when the comparison indicates a non-systemic event.

Fuel cell stack health monitoring using groups of fuel cells

A fuel cell stack that includes a gas diffusion media for the end cells in the stack that has less of an intrusion into the flow field channels of the end cells that the other cells, so as to increase the flow rate through the flow channels in the end cells relative to the flow rate through the flow channels in the other cells. A different diffusion media can be used in the end cells than the nominal cells, where the end cell diffusion media has less of a channel intrusion as a result of diffusion media characteristics. Also, the same diffusion media could be used in the end cells as the nominal cells, but the end cell diffusion media layers could be thinner than the nominal cell diffusion media layers. Further, a higher amount of pre-compression can be used for the diffusion media in the end cells.

Fuel cell stack with improved end cell performance provided by higher modulus of elasticity

Fuel cell stack with improved end cell performance through a diffusion media having lower compressibility

A system and method for breaking-in and humidifying membrane-electrode-assemblies (MEAs) in a fuel cell stack. The method includes performing voltage cycling and humidification of the MEAs in the stack, including one or more temperature steps wherein current density of the stack is cycled within a predetermined range for each of the one or more temperature steps. The method also includes maintaining a fuel cell stack voltage within a predetermined range, and maintaining anode and cathode reactant flows at an approximate set-point during the current density cycling of the one or more temperature steps to break-in and humidify the MEAs in the stack so that the stack is able to operate at a predetermined threshold for a fuel cell stack voltage output capability.

Fast MEA break-in and voltage recovery

Methods and systems for enhancing the performance of fuel cells in fuel cell vehicles. Some embodiments comprise a current control module for controlling the application of a load to the fuel cell and a voltage monitoring module for monitoring one or more voltages within the fuel cell. The current control module may be configured to apply a delay period before applying a load to the fuel cell after the fuel cell has reached an open circuit voltage. In other embodiments, a fixed delay period may be applied before applying a load to the fuel cell after the fuel cell has reached an open circuit voltage or, for example, an incremental set of delay periods that increase as measured temperature decreases.

Systems and methods for enhancing fuel cell vehicle startup

A fuel cell system includes a fuel cell stack and a flow control device that controls a supply of a first phase fluid flowing through the fuel cell stack. A controller monitors at least one parameter of the fuel cell stack and controls the supply to generate pulses of reactant when the at least one parameter crosses a threshold to flush a second phase fluid from said fuel cell stack.

Fluid flow pulsing for increased stability in PEM fuel cell

A fuel cell system that employs a method for determining the potential that a freeze condition will exist after the system is shut-down based on predetermined input, such as ambient temperature, geographical location, user usage profile, date, weather reports, etc. If the system determines that a freeze condition is probable, then the system initiates a purge shut-down of the fuel cell system where water is purged out of the reactant gas flow channels. If the system determines that a freeze condition is unlikely, then it will initiate a normal shut-down procedure without purging the flow channels. The system will then periodically determine if the conditions have changed, and will initiate the purge if a freeze condition subsequently becomes probable.

Fuel cell system water management strategy for freeze capability

A method for preventing a fuel cell voltage potential reversal including determining a relationship between the cell resistance and the current of a fuel cell stack at which a fuel cell voltage potential reversal will occur, operating the fuel cell stack according to a power demand requested, and determining the maximum cell resistance of the fuel cells in the stack. If the maximum cell resistance exceeds a threshold value for the current at which the fuel cell stack is being operated, the operation of the fuel cell stack is restricted to prevent the fuel cell voltage potential from reversing.

Stack operation method aimed at cell reversal prevention

A method for reducing the compression set of GDL during the fuel cell operation and a method for reducing the intrusion of the GDL into flow-field channels, both achieved by pre-compression preconditioning the GDL before placing it into the fuel cell. This preconditioning is performed in order to reduce the loss of compression during the life of the stack and the mal-distribution of reactant gases, and ultimately achieve the benefits of higher power output and more stable performance.

Gas diffusion layer preconditioning for improved performance and operational stability of PEM fuel cells

A system and method for providing a fuel cell stack purge to remove excess water during system shut-down. A compressor is operated at a shut-down speed to force water out of the cathode flow channels and draw water through the membrane from the anode flow channels so that a desired amount of water is removed from the fuel cell stack without over drying the membrane. The cathode shut-down purge flow can be introduced in the forward or reverse direction. Further, the flow of hydrogen fuel can be directed so that it flows through the anode flow channels in an opposite direction to push water out of an anode outlet manifold into the anode flow channels so that it will also be drawn through the membrane by the cathode airflow. Finally, a brief rehydration step is added after the shut-down purge to achieve the desired water content in the cells.

Shutdown strategy for enhanced water management

A flow field plate or bipolar plate for a fuel cell that includes a hydrophilic coating formed on flow field channels extending through a tunnel region between a cell active area and the inlet and outlet manifolds. The flow field plates are an assembly of a cathode side unipolar plate and an anode side unipolar plate. The hydrophilic coating is deposited on the unipolar plates prior to the unipolar plates being assembled into the flow field plate so that line of site deposition processes can be used to coat the flow field channels in the tunnel region. The unipolar plates can be any suitable fuel cell unipolar plates, such as stamped unipolar plates or composite unipolar plates.

Bipolar plate hydrophilic treatment for stable fuel cell stack operation at low power

An electrochemical conversion assembly () is provided comprising a plurality of electrochemical conversion cells arranged in a conductively coupled fuel cell stack (), a condition sensor () operatively coupled to the fuel cell stack (), and a programmable controller operatively coupled to the condition sensor and the fuel cell stack. The condition sensor is configured to measure a rate of change of hydration in the proton exchange membrane and either the condition sensor or the programmable controller is configured to generate a signal indicative of the measured rate of change of hydration. The programmable controller is configured to facilitate control of at least one operating parameter of the electrochemical conversion assembly by monitoring the signal indicative of the measured rate of change of hydration. The condition sensor can be configured to detect a dimensional change or a change in compression of the conductively coupled fuel cell stack as the membrane hydration changes. Additional embodiments are disclosed.

Method of operating a fuel cell stack by monitoring membrane hydration

A bipolar plate for a fuel cell is disclosed including a first unipolar plate having an active surface with a plurality of flowfield channels formed therein. The first unipolar plate further includes an inlet header disposed at a first end of the unipolar plate that is in communication with the active surface, and an outlet header disposed at a second end of the unipolar plate having an exhaust opening formed therethrough. A peripheral edge of the exhaust opening is chamfered and is also in communication with the active surface. The chamfered exhaust opening forms a water removal channel in the bipolar plate. A fuel cell stack including the bipolar plate is also disclosed.

Water removal channel for PEM fuel cell stack headers

Growing community of inventors

Fairport, NY, United States of America

Pinkhas A Rapaport