2+1D modelling of a polymer electrolyte fuel cell with glassy-carbon microstructures

A computationally efficient model of a polymer electrolyte fuel cell (PEFC) is presented, based on a 2+1D FEM modelling approach. This approach is suitable to take the high aspect ratio between the in-plane and the through-plane dimensions of fuel cells into account, and to avoid expensive 3D calculations. The anode and cathode are described by 2D transport models. The coupling between the anode and cathode side is established by a nonlinear point-to-point 1D model representing the membrane electrode assembly (MEA). This 1D boundary value problem is formulated using the computer algebra software Mathematica. The approach is based on the symbolic weak form expressions of a nonlinear system of PDEs. The integrands of the tangential element stiffness matrix and the element residual vector of the coupled FEM problem are computed analytically. These integrands are converted to C code automatically. The model is applied to simulate a micro PEFC without gas diffusion layers (GDLs). The simulations reveal an inhomogeneous in-plane electric current density. Further, neutron radiography data obtained with the micro fuel cell is compared to the calculated water flux between the 1D MEA model and the 2D domains. The model is used to explain the locations where water condensation is found.