Gm Global Technolgoy Operations, Inc.

Robert J Moses

Balasubramanian Lakshmanan

Daniel I Harris

Andrew J Maslyn

Swaminatha P Kumaraguru

Daniel T Folmsbee

Srikanth Arisetty

A fuel cell system includes a fuel cell stack and a controller. The fuel cell stack includes a catalyst and a stack voltage. The controller increases efficiency of the fuel cell stack by minimizing or removing an accumulation of oxides on the catalyst during a low-power operating mode of the fuel cell system. The controller executes a method for dynamically controlling the stack voltage during a detected low-power operating mode. The method includes commanding low-voltage/high-power pulses to the fuel cell stack via the controller at a magnitude and frequency sufficient for minimizing or removing the oxides. The system may include a direct current-direct current (DC-DC) boost converter, with the controller programmed to command the power pulses from the DC-DC boost converter. Or, the controller may be configured to command the power pulses by controlling a feed rate of the oxygen and/or the hydrogen.

Dynamic low-power control of cell voltage in a fuel cell stack during low-power operating modes

A system and method for limiting voltage cycling of a fuel cell stack during a stand-by mode by providing power from a battery to the stack while the stack is turned off. The method includes monitoring the voltage of each of the fuel cells in the fuel cell stack and determining an average cell voltage of the fuel cells in the fuel cell stack. The method also determines whether the average cell voltage of the fuel cells in the fuel cell stack has fallen below a predetermined voltage value and, if so, applies a voltage potential to the fuel cell stack to increase the average cell voltage above the predetermined voltage value.

Powering a fuel cell stack during standby

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Oxford, MI, United States of America

Robert J Moses