Dynamics of low-pressure and high-pressure fuel cell air supply systems

Choosing an operating pressure is a critical decision that defines many characteristics of the fuel cell system. High stack power density is the main selling point of high-pressure systems. On the contrary, low-pressure systems have a benefit of low parasitic loss on air flow devices and less sealing and membrane fracture problems. Here, we look at the dynamic characteristics of both high-pressure and low-pressure systems. The model of a low-pressure air supply system with low-speed blowers is developed. We then perform a dynamical analysis comparing the low pressure system with the high-pressure system equipped with an air compressor. The differences in the transient behavior of the two systems are investigated and their sensitivity to the flow device inertia and the supply manifold volume are explored.