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Fuel Cell Charge Transport

Conduction is the process which dictates the transport of charges through the fuel cell layers, except for the membrane. That means that the lack of adequate contact between the diffusion layer, bipolar plates and cooling plates is the cause of most of the ohmic losses outside of the membrane. There is where most of the overall ohmic loss occur. To help solving that problem, either the membrane needs to be made thinner, or its material needs to be more conductive. History and tests given that, have told us that making the membrane thinner is easier than the alternative. The challenge with making the membrane material more conductive balancing that property with its thermal and chemical stability. 

The image below describes the relationship between membrane thickness and local conductivity:

Source:

SPIEGEL, Colleen. PEM Fuel Cell Modeling and Simulation Using MATLAB®. Burlington, MA, USA: Academic Press, 2008. 440 p.
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