Abstract: The durability of fuel cell power system is one of the key problems of application of fuel cell vehicles. It is researched by analyzing the real-road running datum of the power system on the bus power-train and comparing with the results of the lab test on the durability of the single stack. The fuel cell power system developed by Sunrise Power has driven the bus for about 1 500 h with the mileage of 20 000 km. The degradation speed of fuel cell is 45 μV/h at the common operating duty (120 A), and the total attenuation is less than 7%. The single stack is tested under the dynamic loading conditions for 1 000 h on the test-station, and the stack behaves steadily with a degradation speed of 12 μV/h. By comparing the two behaviors between the power system on bus and the stack on test-station, it is concluded that the operating conditions provided by the supporting system in the fuel cell power system is not enough to promise good durability of the stack. And the durability can be improved by optimizing the capability of the supporting system.

Key words: Durability, Fuel cell, Fuel cell engine, Fuel cell vehicle, Humidifying, Impurity