Study of Piezoelectric Proton Exchange Membrane Fuel Cells (PZT-PEMFC)

The amplitude of the vibration of a piezoelectric (PZT) device produces an oscillating flow that changes the chamber volume along with the curvature variation of the diaphragm. In this study, an actuating micro-diaphragm with a piezoelectric device is utilized in an air flow field in proton exchange membrane fuel cell (PEMFC) systems, called PZT-PEMFC. This newly designed gas pump, with a piezoelectric actuation structure, can feed air into the system of an air-breathing PEMFC. When the actuator moves outward to increase the cathode channel volume, the air is sucked into the chamber; moving inward decreases the channel’s volume and compresses air into the catalyst layer, thus enhancing the electrochemical reaction. In addition, the PZT-PEMFC solves the water-flooding problem for fuel cells, since its performance serves as an open cathode stack configuration and can be applied in a fuel cell stack without an external air supply device. The objective of the study proposes five different PZT-PEMFCs to be used for determining the optimal cell performance under different open-area ratios, PZT vibration frequencies, valve designs, and flow field designs. Besides, the reaction area is 4 cm2. The maximum power density is around 0.18 W/cm2 under normal operating temperatures, which for the PZT-PEMFC of this study is 50℃, and the optimal vibration frequency is 180Hz. Furthermore, the 3-D theoretical model for PZT-PEMFCs is also developed to investigate its characteristics and performance to make comparisons with experimental results.