Standard Model of CCL Operation

Continuity equations including all species and processes have been presented in Eikerling (2006). Several simplifications led to the set of steady-state equations, which will be presented in two blocks (A and B). Block A comprises the governing equations for electrochemical processes, involving proton transport. 

Below in this chapter, an equivalent system of equations, written in terms of the oxygen concentration c, will also be used  

Block B comprises governing equations for coupled water fluxes in the CCL, including water formation and vaporization exchange  

Block A contains one free parameter, jo, the total current density of the PEFC. Fixing this parameter defines the working point of the PEFC. Block B has two free parameters, the total water flux and the liquid water fraction of the total water flux at X = IcL- A self-consistent solution to find these two parameters demands a full MEA model. 

The oxygen partial pressure is related to the oxygen concentration in the gas phase via the ideal gas law,p(jc) = RgTc x). To obtain the oxygen concentration in solution, Henry s law constant (solubility) of oxygen must be used.  

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