Normally closed electrostatic microvalve with pressure balance mechanism for portable fuel cell application

This paper describes the fabrication and evaluation of an electrostatic microvalve to control the concentration of methanol in direct methanol fuel cell (DMFC) systems. The microvalve uses a novel pressure balance mechanism to realize normally closed operation against pressurized fuel, and maintained close state up to an input pressure of 40 kPa as designed. The driving voltage ranged from 50 V to 110 V depending on the input pressure. The measured results were compared with simulation results, and showed fair agreement with simulation results. Finally, the developed microvalve was applied to a prototyped portable DMFC system, and stable electric generation was demonstrated.