Distinguishing the Different Irreversibilities

At various points in this chapter it has been asserted that such and such an overvoltage is important in so and so conditions . For example, it has been said that in SOFC the ohmic voltage drop is more important than activation losses. What is the evidence for these claims  

The current interrupt test is particularly easy to perform with single cells and small fuel cell stacks. With larger cells the switching of the higher currents can be problematic. Current interrupts and electrical impedance spectroscopy give us two powerful methods of finding the causes of fuel cell irreversibihties, and both methods are widely used. 

We now have a snfficient nnderstanding of the principles of fuel cell operation, and in the following chapters we look mnch more closely at the practical details of different types of fuel cell systems. 

Amphlett J.C., Baument R.M., Mann R.E., Peppley B.A., Robrage P.R., and Harris T.J. (1995) Performance modelling of the BaUard Mark V solid polyma- electrolyte fuel cell . Journal 

Appleby A.J and FouUces F.R. (1993) A Fuel Cell Handbook, 2nd ed., Kreiger Publishing Co., 

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