Operation of polymer electrolyte membrane fuel cells with dry feeds: Design and operating strategies

The operation of polymer electrolyte membrane fuel cells (PEMFCs) with dry feeds has been examined with different fuel cell flow channel esigns as functions of pressure, temperature and flow rate. Auto-humidified (or self-humidifying) PEMFC operation is improved at higher pressures nd low gas velocities where axial dispersion enhances “back-mixing” of the product water with the dry feed. We demonstrate auto-humidified peration of the channel-less, self-draining fuel cell, based on a stirred tank reactor; data is presented showing auto-humidified operation from 25 o 115 ◦C at 1 and 3 atm. Design and operating requirements are derived for the auto-humidified operation of the channel-less, self-draining fuel ell. The auto-humidified self-draining fuel cell outperforms a fully humidified serpentine flow channel fuel cell at high current densities. The ew design offers substantial benefits for simplicity of operation and control including: the ability to self-drain reducing flooding, the ability to niformly disperse water removing current gradients and the ability to operate on dry feeds eliminating the need for humidifiers. Additionally, the esign lends itself well to a modular design concept. 2005 Elsevier B.V. All rights reserved.