Development of Micro-diaphragm Flow Channel with Piezoelectric Effect in Polymer Electrolyte Fuel Cells
Date Issued
2007
Date
2007
Author(s)
Cheng, Li-Wei
DOI
zh-TW
Abstract
Previous studies showed that the amplitude of vibration of a piezoelectric (PZT) device produces an oscillating flow which changes the chamber volume along with curvature variation of the diaphragm. In a similar way, the actuating micro-diaphragm with piezoelectric effects is utilized as one of the flow channels PEM fuel cell systems, named as PZT-PEMFC. This newly designed gas pump with a piezoelectric actuation structure can feed air into the system of an air-breathing PEM fuel cell. While the actuator is moving outward to increase the cathode channel volume, the air is sucked in the chamber; moving inward to decrease the cathode channel volume, then air is compressed into the catalyst layer and enhances the chemical reaction. Also, the air-standard PZT-PEMFC Cycle is proposed to describe an air-breathing PZT-PEMFC. At the same time, a novel design of PZT-PEMFC’s has been developed and a three-dimensional, transitional model has been successfully built to account for its major phenomena and the fuel cell performance. Moreover, at high frequencies, PZT actuation leads to more stable current output, drained water, sucked oxygen, higher hydrogen consumption, and also overcomes the concentration losses. In addition, the equivalent ratio is used as an important parameter for the novel PZT-PEMFC. At hydrogen lean condition, an air-breathing PZT-PEMFC saves more hydrogen and gradually increases the current generation.
Subjects
壓電元件
壓電可變式質子交換膜燃料電池
氣體泵
自然進氣
水氣排出量
燃料使用率
Piezoelectric effect
PZT-PEMFC
Micro-diaphragm
air-breathing
current generation
Type
thesis