Fuel cell life counter and method of managing remaining life
AssigneeGM Global Technology Operations LLC
InventorYeh-Hung Lai
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Abstract
According to one embodiment of the present invention, a fuel cell life counter is configured to determine membrane degradation using fuel cell cycling data and S-N curve data for the membrane. According to another embodiment of the present invention, a method of managing remaining fuel cell life is provided where variables like membrane dehydration rate, water content, temperature, and heating/cooling rate are controlled as a function of the remaining life of the fuel cell. Additional embodiments are provided where fuel cell life counters and methods of managing remaining life are independent of S-N curve data and the use of fatigue life contour plots.
Claims18
A method of operating an electrochemical conversion assembly comprising a plurality of electrochemical conversion cells arranged in a conductively coupled fuel cell stack, wherein respective ones of said cells comprise membrane electrode assemblies positioned between first and second reactant flowfields and said membrane electrode assemblies comprise a proton exchange membrane, said method comprising:
- initiating operation of said fuel cell stack according to an initial set of operating parameters comprising hydration, wherein said operation of said fuel cell stack runs through a plurality of operational cycles characterized by changes in humidification, of said membrane electrode assemblies;
- extracting cyclic stress data representative of said plurality of operational cycles;
- determining a life spent value LX representing stack life expended over said plurality of operational cycles, wherein said life spent value LX is a function of fatigue life data of the fuel cell stack and a stress histogram that is derived from said cyclic stress data arising from said cyclic stress imparted upon said membrane electrode assembly over said plurality of operational cycles;
- determining an actual usage value LU representing a number of said operational cycles executed from initiation of said fuel cell stack operation, wherein said actual usage value LU is substantially independent of stress imparted upon said membrane electrode assembly over said plurality of operational cycles;
- comparing said life spent value LX to said actual usage value LU;
- and
- controlling at least one operating parameter comprising hydration of said electrochemical conversion assembly as a function of said comparison of said life spent value LX to said actual usage value LU.
A method of determining life expended in an electrochemical conversion assembly comprising a plurality of electrochemical conversion cells arranged in a conductively coupled fuel cell stack, wherein respective ones of said cells comprise membrane electrode assemblies positioned between first and second reactant flowfields and said membrane electrode assemblies comprise a proton exchange membrane, said method comprising:
- initiating operation of said fuel cell stack according to an initial set of operating parameters comprising hydration, wherein said operation of said fuel cell stack runs through a plurality of operational cycles characterized by changes in humidification, of said membrane electrode assemblies;
- extracting cyclic stress data representative of said plurality of operational cycles;
- and
- determining a life spent value LX representing stack life expended over said plurality of operational cycles, wherein said life spent value LX is a function of fatigue life data of the fuel cell stack and a stress histogram that is derived from said cyclic stress data arising from said cyclic stress imparted upon said membrane electrode assembly over said plurality of operational cycles.
An electrochemical conversion assembly comprising a plurality of electrochemical conversion cells arranged in a conductively coupled fuel cell stack and a programmable controller operatively coupled to said fuel cell stack, wherein:
- respective ones of said cells comprise membrane electrode assemblies positioned between first and second reactant flowfields of said stack;
- said membrane electrode assemblies comprise a proton exchange membrane;
- said programmable controller is configured to control of at least one operating parameter of said electrochemical conversion assembly by
- facilitating fuel cell stack operation according to an initial set of operating parameters comprising hydration, wherein said operation of said fuel cell stack runs through a plurality of operational cycles characterized by changes in humidification, of said membrane electrode assemblies;
- facilitating the extraction of cyclic stress data representative of said plurality of operational cycles;
- facilitating the determination of a life spent value LX representing stack life expended over said plurality of operational cycles, wherein said life spent value LX is a function of fatigue life data of the fuel cell stack and a stress histogram that is derived from said cyclic stress data arising from said cyclic stress imparted upon said membrane electrode assembly over said plurality of operational cycles;
- facilitating the determination of an actual usage value LU representing a number of said operational cycles executed from initiation of said fuel cell stack operation, wherein said actual usage value LU is substantially independent of stress imparted upon said membrane electrode assembly over said plurality of operational cycles;
- facilitating the comparison of said life spent value LX to said actual usage value LU;
- and
- controlling at least one operating parameter comprising hydration of said electrochemical conversion assembly as a function of said comparison of said life spent value LX to said actual usage value LU.
Dependencies are inferred from the claim text.