In-vehicle algorithm for fuel cell stack health quantification

A method for determining health of fuel cells in a fuel cell stack, said method comprising:

• performing a single hydrogen takeover test that includes maintaining a constant flow of hydrogen to an anode side of the fuel cell stack and shutting off a flow of air to a cathode side of the fuel cell stack when a predetermined concentration of hydrogen in the anode side is achieved;
• identifying a predetermined drop in voltage of the fuel cell stack after the single hydrogen takeover test that includes identifying the drop in voltage of the fuel cell stack in a first stage, a second stage and a third stage;
• identifying a catalyst surface area and a catalyst support surface area of catalyst layers in the fuel cell stack;
• determining a total parasitic current of membranes in the fuel cell stack after a predetermined drop in voltage of the first stage is complete;
• determining a cross-over parasitic current of the membranes in the fuel cell stack from the total parasitic current after a predetermined drop in voltage of the third stage is complete;
• determining a shorting resistance of the membranes in the fuel cell stack from the total parasitic current and from the cross-over parasitic current using the drop in voltage from the second stage;
• calculating the catalyst surface area and the catalyst support surface area after the second stage is complete;
• and
• comparing the difference between the identified catalyst surface area and the calculated catalyst surface area to estimate the change in the catalyst surface area and comparing the difference between the identified catalyst support surface area and the calculated catalyst support surface area to estimate the change in the catalyst support surface area.

A method for determining fuel cell health of fuel cells in a fuel cell stack, said method comprising:

• performing a hydrogen takeover test that includes maintaining a constant flow of hydrogen to the anode side of the fuel cell stack and shutting off a flow of air to a cathode side of the fuel cell stack when a predetermined concentration of hydrogen in the anode side is achieved;
• identifying a catalyst surface area and a catalyst support surface area of catalyst layers in the fuel cell stack;
• determining a total parasitic current;
• determining a cross-over parasitic current and a shorting resistance;
• calculating the catalyst surface area and the catalyst support surface area;
• and
• comparing the difference between the identified catalyst surface area and the calculated catalyst surface area to estimate the change in the catalyst surface area.