Biased AC electroosmosis micropump for water management in PEM fuel cells

Proton exchange membrane (PEM) fuel cells are among the most promising fuel cell technologies. Recent experimental and numerical investigations on PEM fuel cells identified water management as one of the most critical issues for designing robust, high-performance PEM fuel cells. Proper water management within the cell is therefore essential, as dehydration of the membrane or flooding of the cathode result in increasing resistive losses. Flooding reduction in the fuel cell is commonly done by removing water with excessive reactant (H₂ or O₂) flow rates and elevated gas pressures. This mixture makes air delivery the largest parasitic load on fuel cells. Typically, this type of air delivery consumes more than 20% of the fuel cell power. As an alternative, we have developed a novel biased AC electroosmtic micropump for PEM fuel cell applications that can be fabricated with micro-electro-mechanical-systems (MEMS) compatible semiconductor microfabrication. This research paper will experimentally demonstrate the bi-directional pumping action that can prevent flooding, increase power density, and ensure stable performance of fuel cell by removing water from flooded regions and redistributing it to under-saturated regions. We also have developed an integrated complementary metal oxide semiconductor (CMOS) feedback circuit for the control of micropump.