Fuel cell re-oxidation prevention during operation stop

A method for operating a fuel cell system, the method comprising:

• in response to detecting that an operation stop condition is present in a fuel cell system, detecting, by a controller coupled to receive at least one signal from a corresponding sensor, a temperature of a fuel cell stack of the fuel cell system;
• in response to the temperature of the fuel cell stack being greater than a predefined first threshold temperature, setting a dosing rate of methanol and water to a predefined first dosing rate;
• in response to the temperature of the fuel cell stack being greater than a predefined second threshold temperature, setting the dosing rate of methanol and water to a predefined second dosing rate, the predefined second dosing rate including a proportion of methanol greater than a corresponding proportion of methanol in the predefined first dosing rate;
• and
• initiating providing a mixture of methanol and water to the fuel cell system at one of the predefined first dosing rate and the predefined second dosing rate to prevent re-oxidation of an anode of the fuel cell stack.

A fuel cell system comprising:

• a temperature sensor configured to detect temperature of a fuel cell stack of the fuel cell system;
• a first tank including a first valve and configured to store methanol;
• a second tank including a second valve and configured to store water;
• and
• a controller communicatively coupled to receive signals from the temperature sensor and control each of the first valve and the second valve, the controller being configured to:
• in response to an operation stop condition being present and the temperature of the fuel cell stack being greater than a predefined first threshold temperature, set a dosing rate of methanol and water to a predefined first dosing rate;
• in response to the operation stop condition being present and the temperature of the fuel cell stack being greater than a predefined second threshold temperature, set the dosing rate of methanol and water to a predefined second dosing rate, the predefined second threshold temperature being greater than the predefined first threshold temperature, and the predefined second dosing rate including a proportion of methanol per dose greater than a corresponding proportion of methanol per dose of the predefined first dosing rate;
• and
• initiate operating at least one of the first valve and the second valve to deliver a mixture of methanol and water at one of the predefined first dosing rate and the predefined second dosing rate to prevent-re-oxidation of an anode of the fuel cell stack.