Dresden 2006 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 4: New Experimental Techniques

CPP 4.9: Talk

Monday, March 27, 2006, 16:30–16:45, ZEU Lich

Visualization of liquid water in PEM Fuel Cells with Neutron Radiography — •Ingo Manke^1,2, Nikolay Kardjilov², Christoph Hartnig³, André Hilger^2,4, Markus Strobl⁴, Manfred Grünerbel³, Wolfgang Treimer⁴, Werner Lehnert³, and John Banhart^1,2 — ¹Technische Universität Berlin, Fakultät 3 — ²Hahn-Meitner-Institut Berlin, SF 3 — ³Centre for Solar Energy and Hydrogen Research (ZSW) — ⁴University of Applied Science (TFH), FB 2

A key issue in the development of Polymer Electrolyte Membrane Fuel Cells (PEMFC) is the optimization of the mass transport, i.e. the transport of liquid water, in the gas diffusion layers and the gas channels of the flow field. The water is produced by conversion of hydrogen fuel and oxygen into electrical energy. However, the production of too much water can disturb the gas flows and causes a breakdown in the output power. Neutron Radiography (NR) is a unique experimental technique to study the two-phase flow inside operating PEMFCs. Neutrons penetrate quite thick metal components and at the same time they are highly sensitive to hydrogen containing materials. The accumulation of water was investigated under different operating conditions. Beginning from *dry* and going to *wet* conditions, time and location of the water accumulation were recorded, analyzed and quantified by NR. First liquid water droplets develop in the gas diffusion layers. After some time water drops appear at the side of the gas channels in the flow field. The drop sizes are increasing until the whole channel is filled and the gas flow inside the