Test procedure for the prediction of water transport in polymer electrolyte fuel cells

Water plays a crucial role for the operation of polymer electrolyte fuel cells. The distribution and state of water in the membrane-electrode-assembly (MEA) not only impacts the performance of the cell, but also its degradation and freeze-start capability. It is therefore important to have a model that precisely predicts the distribution of water across the fuel cell for arbitrary inlet conditions. Unfortunately, water transport coefficients reported in the literature vary by orders of magnitude while operation conditions and other crucial properties of the cell are not precisely known. Furthermore, a large amount of data is simply outdated due to improvements in measurement techniques and setups as well as fuel cell components. In the present work, we have devised a test procedure for water transfer measurements with state of the art MEAs. In parallel, we have derived a semi-empirical model and parametrized it with measured data. The model allows predicting MEA water fluxes and profiles of temperature and concentration over a wide operation range, relevant for passenger as well as heavy duty automotive applications.