In situ investigation of water transport in an operating PEM fuel cell using neutron radiography: Part 1 – Experimental method and serpentine flow field results

The Hydro-electro-thermal Performance of Air-cooled, Open-cathode Polymer Electrolyte Fuel Cells: Combined Localised Current Density, Temperature and Water Mapping

“…This technique is based on attenuation of a neutron by hydrogencontaining compounds such as water, and transparency to neutrons of most fuel cell construction materials (aluminium, stainless steel). Neutron imaging can identify water in the in-plane orientation (with the membrane place parallel to the beam) and through-plane orientation (with the membrane plane perpendicular to the beam), enabling in the first case to differentiate the water content from the cathode and the anode [48][49][50] and in the second case the effect of different designs, components, and operating conditions [45,[51][52][53][54][55][56][57][58][59][60][61][62][63][64][65]. Neutron imaging has been combined with other modelling and experimental techniques, such as current mapping [66], CFD models validation [32,51,65], optical imaging [47], neutron scattering [61] and localised EIS [45].…”

Visualization of Fuel Cell Water Transport and Performance Characterization under Freezing Conditions

“…Also, published data were used to select "optimal" geometrical features, such as the flow field channel cross-section. The apparatus was designed specifically for application of the neutron imaging method for vizualization of liquid water accumulation and dynamics at the scale of the flow field channels and gas diffusion layers [27,28,116].…”

“…This technique was later widely used to study water transport in gas channels under various fuel cell operating conditions [20][21][22][23][24][25][26]. Neutron radiography provided another in-situ visualization technique and was utilized by a number of groups to visualize and quantify water retention in the GDL, under the lands, and in the gas channels [27][28][29][30]. Higher water retention was found at the U-bends and under the lands of the serpentine channels.…”

“…General Motors, a world leader in fuel cell technology for automotive applications, has a long record to use neutron radiography to visualize water in an operating fuel cell [97][98][99][100]. Based on their two-dimensional neutron radiography results, the liquid water accumulation in the GDL and bipolar plate channels has been mapped and quantified.…”

Failure Analysis of Polymer Electrolyte Fuel Cells

“…Such measures can ensure that the channels remain pressurised along their entire lengths and reduce the chance of flooding whereby high upstream pressures and low downstream pressures are established causing liquid water to be pushed down and accumulate in downstream regions of the flow fields [60]. Liquid water can inevitably accumulate in any region where the gasphase flow becomes stagnant, particularly in abrupt 180° bends often seen for serpentine flow fields [61,62,63].…”