Water Visualization and Flooding in Polymer Electrolyte Membrane Fuel Cells

Regions of flooding inside a PEM fuel cell usually cannot be identified because most cells are designed with a metal casing. Flooding can easily be detected by performance drops during cell operation, but it is difficult to correspond these performance drops with exactly what is happening in specific regions. Segmenting the membrane into regions and measuring the current in each area alleviates this problem. Building the fuel cell out of clear polycarbonate blocks, coupled with the added current measurements, will give a better understanding of fuel cell flooding. This study seeks to correlate visualization of water flooding with cell performance drops. Small-scale designs were used to model a plug flow reactor (PFR) and continuous-stirred tank reactor (CSTR). All experiments were conducted at room temperature with constant load resistance. The cell was operated under autohumidification conditions. Results were inconsistent between CSTR and PFR design cells. Flooding caused a drop in performance with the CSTR cell initially, but later performance leveled out so that flooding had no effect. The PFR cell design showed performance drops as flow channels became flooded, but this was complicated by membrane degradation. Further research will be conducted using this experimental setup with segmented, clear block fuel cells.