Performance Enhancement of PEM Fuel Cells by Use of Anode Gas Ultrahumidification via Ultrasonic Nebulization

A novel anode feed gas humidification method was investigated as part of an effort to reduce the mass, volume, and cost of the balance of plant for a commercial PEM fuel cell system. Ultrasonic fountain nebulization was utilized to ultrahumidify the anode feed gas for a PEM fuel cell. Ultrasonic nebulization ultrahumidification was found to increase the average voltage of the fuel cell by several percent, and reduce the amplitude of cyclic overvoltage. Most importantly, this humidification technique greatly increased the thermal fault tolerance of the PEM fuel cell; that is, this humidification technique allowed the PEM fuel cell to operate effectively at high temperatures without a need to increase the vapor pressure of the humidification water. In addition, this humidification technique shows potential to be used to increase the overall energy conversion efficiency of a PEM fuel cell system.