• Roger Penn

    October 13, 2022 at 12:41

    The partial pressure of oxygen at the catalyst layer is an important parameter for fuel cell performance (the cathode is the rate limiting step in the overall fuel cell reaction). Given that the partial pressure of O2 at 10,000 m altitude is very low, a compressor must be used to bring the pressure up to stack operating conditions or the stack will not produce the required power. This usually means a big, heavy compressor, that we don’t want on an aircraft (want optimized gravimetric power density for an aircraft fuel cell system). The ambient temperature is also very cold at altitude and the incoming air must be warmed up to stack operating conditions (again, by compressing the gas which heats it). So a custom stack design is usually required to run at low operating pressure (the stack must also be able to operate at any angle, even upside down) for aircraft applications.

  • Björn Lüssow

    October 13, 2022 at 19:08

    Thanks, Roger! I learned a lot!

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