Gm Global Technolgoy Operations, Inc.

Srikanth Arisetty

Balasubramanian Lakshmanan

Andrew J Maslyn

Herman K Phlegm

Aaron R Rogahn

Edgar P Calderon

Rajesh K Bhagirath

Robert J Moses

A method for constant pressure regulation of battery cells includes disposing the cells in a stacked arrangement within a battery cell placement volume of an apparatus configured to maintain a constant pressure on the cells, providing a gas pressure within a chamber of the apparatus, thereby causing an initial pressure to be applied on the battery cells, and detecting an expansion of the battery cells during a predetermined timespan using a linear displacement sensor. During the predetermined timespan, if the detected expansion is less than a maximum allowable expansion minus a predetermined measurement error, then the gas pressure within the chamber is increased, and if the detected expansion is greater than the maximum allowable expansion plus the predetermined measurement error, then the gas pressure within the chamber is decreased. An apparatus for constant pressure regulation of battery cells is also provided.

Apparatus and method for constant pressure regulation of one or more battery cells

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

Disclosed are fuel cell architectures, thermal sub-systems, and control logic for regulating fuel cell stack temperature. A method is disclosed for regulating the temperature of a fuel cell stack. The method includes determining a pre-start temperature of the fuel cell stack, and determining, for this pre-start temperature, a target heating rate to heat the stack to a calibrated minimum operating temperature. The method then determines a hydrogen bleed percentage for the target heating rate, and executes a stack heating operation including activating the fuel cell stack and commanding a fluid control device to direct hydrogen to the cathode side at the hydrogen bleed percentage to generate waste heat. After a calibrated period of time, the method determines if an operating temperature of the stack exceeds the calibrated minimum stack operating temperature. Responsive to the operating temperature being at or above the minimum operating temperature, the stack heating operation is terminated.

Fuel cell architectures, thermal systems, and control logic for efficient heating of fuel cell stacks

Systems and methods for initiating voltage recovery procedures in a fuel cell system based in part on an estimated specific activity over the life of a fuel cell catalyst are presented. In certain embodiments, SA loss of catalyst and electrochemical surface area loss of a FC system may be estimated. An output voltage of the FC system may be estimated based on the estimated SA loss and the electrochemical surface area loss. An amount of recoverable voltage loss may be determined based on a comparison between the estimated output voltage and a measured output voltage. Based on the determined amount of recordable voltage loss, a FC system control action (e.g., a voltage recovery procedure) may be initiated.

Growing community of inventors

Novi, MI, United States of America

Srikanth Arisetty