Quite a bit on what it takes to control a fuel cell stack in vehicle and stationary applications: www-personal.umich.edu/~annastef/FuelCellPdf/pukrushpan_thesis

Quite a bit on what it takes to control a fuel cell stack in vehicle and stationary applications: www-personal.umich.edu/~annastef/FuelCellPdf/pukrushpan_thesis.pdf I find it interesting to read that: o To get the kind of highly variable "transient response" (change in power output) required for automotive applications, the author proposes using a chemical battery as part of the power management system, as the fuel cell system can't itself respond quickly enough. o The control system is as much or more challenging than that of an internal combustion engine, requiring control of these sub-systems: __ * Reactant (hydrogen) flow subsystem __ * Heat and Temperature subsystem __ * (pure distilled) Water Management subsystem __ * Power management subsystem __ * If not fueled by hydrogen, an on-board fuel processor subsystem to break the chosen carbon-based fuel down to hydrogen With just hydrogen fuel, it still takes an air compressor, three heat exchangers (fuel temp, fuel cell stack heat extraction, compressed air heat extraction), an air humidifier, a water separator, a power converter, a chemical battery (and software of course, to implement the control system) to make it all work in vehicle applications.