Electrostatic broadening of current-free spots in a fuel cell stack: The mechanism of stack aging?

We develop a model of a fuel cell stack focused on effects due to current-free spots in the individual cells. The spots disturb potential of the bipolar plate over the distance, which exceeds the physical size of the spot. The variation of plate potential translates into the growth of cell local current around the spot. Analytical solution to a model problem shows that the amplitude of voltage perturbation grows quadratically with the spot radius and linearly with the resistivity of the bipolar plate and with the mean current in the stack. Possible scenario of stack aging due to this electrostatic broadening of spots is discussed.