Electrical coupling in proton exchange membrane fuel cell stacks: mathematical and computational modelling

A mathematical model describing the effects of electrical coupling of proton exchange membrane unit fuel cells through shared bipolar plates is developed. Here, the unit cells are described by simple, steady-state, 1D models appropriate for straight reactant gas channel designs. A linear asymptotic version of the model is used to give analytic insight into the effect of the coupling, including estimates of the extent of the coupling in terms of the number of adjacent cells affected. An efficient numerical method is developed to solve the non-linear coupled system. Numerical results showing the effects on stack voltage due to a single cell with anomalous oxidant flow rate are given. The effects on stack performance due to end plate effects are also given. It is shown that electrical coupling has a significant effect on fuel cell performance.