Design concepts and durability challenges for mini fuel cells

Abstract

Abstract Recent developments in direct methanol fuel cell (DMFC) technology are described. Starting in 2006, early commercialization of DMFC power sources of 20–100 W for recreational vehicles and boats and, most recently, 1 kW level DMFC systems for forklift power source applications has taken place. This development clearly suggests a significant degree of maturity of mainstream DMFC technology. Further, very recent technology advancements have opened the door to DMFC power sources of high system simplicity, which is of special significance to micro‐fuel cell applications. They include a DMFC platform with direct supply of 100% methanol into the DMFC anode, based on spontaneous supply of water from the cathode to the anode within the cell, thereby eliminating any need for water pumping around the cell. Fuel utilization of the order of 90% is achievable even with methanol‐leaky poly(perfluorosulfonic acid) (poly(PFSA)) membranes under such direct supply of 100% methanol to the DMFC anode, by adjusting the feed of neat methanol to a stoichiometric flow rate near 1.1. Quantitative analysis is provided for the requirements to embed a DMFC power system into small spaces defined by sizes of consumer electronics devices. The results show that, while implementation of DMFC power sources for hand‐held or laptop power applications is feasible with present technology through the use of external chargers, embedding such power units inside hand‐held devices is awaiting increase of the DMFC power density achievable under the operation conditions relevant for hand‐held applications, from the present level of 50–100 to over 300 mW cm −3 .