A visualization study on relationship between water-droplet behavior and cell voltage appeared in straight, parallel and serpentine channel pattern cells

It is a critical issue to understand the relationship between water-droplet behavior and cell voltage for the establishment of PEFC water management. We fabricated three cells, whose channel pattern is different: straight one channel, parallel three channels and serpentine one channel. We operated these different channel-pattern cells and visualized water droplets in cathode channel, with systematically changing operation condition to quantitatively compare the performance and water droplet behavior between the cells. Successive process of water behavior, named as flooding, plugging and flushing, emerged in every channel-pattern cell. However, the each channel pattern cell also has inherent water behavior, showing particular cell voltage variation. Within our experimental condition, the serpentine one channel cell showed a superior tolerance to flooding and the highest performance among the three cells.

► The relationship cell voltage and water behavior was investigated.
► Every channel cell had inherent water behavior, showing particular voltage variation.
► The voltage in straight one channel cell showed monotonous and sudden change.
► That in parallel three channels cell showed step-wise change.
► That in serpentine one channel cell showed saw-edge-wise change.