A Planar Normally - Closed Piezoelectric Valve For Micro Fuel Cell Applications

摘要

Portable methanol micro fuel cell systems are becoming promising candidates due to their high energy density. The relevant micro fluid control components must be small to reduce the impact of balance of plant of micro fuel cell energy density. The piezoelectric actuation of microvalve structures is attractive due to the relative simplicity of the actuator design, very little power in static operations, rapid response, and high work energy density. We report on the development of a micro-electro-mechanical systems (MEMS) valve that is designed to meet the planar structure requirement of micro fuel cells. The optimized actuating diaphragm and the valve seat are etched in silicon wafers. A piezoelectric bimorph disc is used to drive the actuating diaphragm and open the outlet of the valve. The pressure differential between the valve chamber and the outlet and the initial pressure are employed to reduce the leak rates. The dimension of the valve is 20mm in diameter and 2mm in thickness. The effective opening force of 2.19N and the maximum effective displacement of 10μm can be produced. The design, simulation, fabrication and performance are presented.