The longevity of proton-exchange membrane fuel cells is governed by degradation processes whose rates depend on local operating conditions such as temperature, humidity, liquid-water saturation, and reactant availability. Along-the-channel gradients imposed by the flow field can therefore be relevant when interpreting operating behavior and when formulating models intended to support control and system studies. The AlphaPEM framework provides a dynamic through-plane description of electrochemical and water-management states, but in its baseline form does not resolve how these states vary along the gas channels.
This paper presents a pseudo-2D (1+1D) extension of AlphaPEM that couples a discretized along-the-channel gas-channel model to a segment-wise MEA submodel. For each axial segment, the MEA equations are evaluated with local boundary conditions obtained from the channel (e.g., reactant and vapor concentrations), while retaining the key dynamic states of the original formulation, including cathode over-potential and membrane/catalyst-layer water variables.
Electrical coupling between segments is treated explicitly. In addition to a uniform-current closure, an equipotential bipolar-plate closure is implemented, in which a common cell voltage is determined such that the sum of segment currents matches a prescribed operating point. The same structure enables frequency-domain analysis and interpretation in terms of segment-resolved apparent impedances. The contribution focuses on model formulation and coupling strategy and illustrates how axial gradients can be represented within an efficient, control-relevant PEM fuel cell model.