Methanol Concentration Control for Direct Methanol Fuel Cells

Direct methanol fuel cells (DMFCs) can provide a very lightweight and compact source of electric power for individual soldiers if they can be fueled with pure methanol. Used as a charger for rechargeable Li-ion batteries, they promise an attractive hybridpower source for future soldier systems. A key technology that will enable concentrated methanol fuel is a system to control the concentration of methanol in the small volume of dilute solution that flows through the fuel cell stack. We propose aninnovative methanol concentration control system that will enable a DMFC to use pure methanol fuel. The system responds twenty times more quickly than conventional techniques and is lightweight, compact, low-power, and reliable. In Phase I we will provethe feasibility of the system by: (1) assembling a proof-of-concept methanol concentration control system, (2) proving the operation of the system using a direct methanol fuel cell, and (3) using the results of the Phase I development and testing to designa prototype system for Phase II. In Phase II we will demonstrate the operation of a complete, self-contained, 15 W DMFC that is powered by highly concentrated methanol. The methanol concentration control system can enable an order-of-magnitude improvementin the energy density available from a DMFC system compared to fueling with dilute solution. Our concept for methanol concentration control is simple, compact, lightweight, and straightforward to integrate with a DMFC stack. Commercial applicationsinclude portable power sources for laptop computers, recreational equipment, and portable medical devices.