Small electronic devices require small, compact and lightweight power supplies. Direct methanol fuel cells (DMFCs) offer the potential for double the lifetime of lithium ion batteries. We have designed a process for micromachining direct methanol fuel cells using traditional micromachining techniques and macroassembly. Direct methanol fuel cells oxidize methanol through a catalytic reaction producing carbon dioxide and hydrogen. Hydrogen is further oxidized into hydrogen ions through a second catalytic reaction, producing electrons. We have micromachined flow fields and current collectors for the anode (methanol) side in both <100> and <110> silicon. Using laser ablation, we have opened fluidic channels through the back of the wafer for attaching fluid feed tubes. Aluminum is deposited as a current collector. The fuel cell is assembled using a commercial membrane electrode assembly (MEA), which contains the solid polymer proton exchange membrane (PEM) and catalysts. Sealing is provided using an epoxy. Simulated and actual results are presented.
[1]
G. Kovacs.
Micromachined Transducers Sourcebook
,
1998
.
[2]
William H. Smyrl,et al.
A Miniature Methanol/Air Polymer Electrolyte Fuel Cell
,
1999
.
[3]
N. Djilali,et al.
APPLICATION OF MICROSCALE TECHNIQUES TO FUEL CELL SYSTEMS DESIGN
,
2000
.
[4]
John Davey,et al.
Recent advances in direct methanol fuel cells at Los Alamos National Laboratory
,
2000
.
[5]
Woo Young Sim,et al.
Fabrication of micro power source (MPS) using a micro direct methanol fuel cell (/spl mu/DMFC) for the medical application
,
2001,
Technical Digest. MEMS 2001. 14th IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.01CH37090).
[6]
James Larminie,et al.
Fuel Cell Systems Explained
,
2000
.