Direct methanol fuel-cell combined with a small back-up battery

Abstract A description is given of a fuel-cell power-supply for mobile phones that operates at room temperature and ambient pressure using liquid methanol and ambient air. The unit is a hybrid system in which a direct methanol fuel-cell (DMFC) and a back-up battery are connected in parallel to meet the power requirements of mobile phones. Electrochemical catalysts for the anode and the cathode of the DMFC are synthesized and Nafion-115 is used as the electrolyte. A 2 M methanol solution is filled in the feed reservoir, and the cathode is exposed to ambient air. Eight unit cells, each having 9 cm 2 of active area, are connected in series in order to raise the output voltage to 2.5–3.9 V, which is the typical voltage range for most mobile phones. Also, to simulate the practical application, an electric circuit is included to increase the output voltage of the back-up battery to repeat the charge–discharge cycle. During talk mode, the DMFC supplies 10–50% of the required power and the back-up battery supplies the remainder. In standby mode, the DMFC covers 100% of the required power and charges the back-up battery.

[1]  William H. Smyrl,et al.  A Miniature Methanol/Air Polymer Electrolyte Fuel Cell , 1999 .

[2]  Josefin Meusinger,et al.  Process analysis of a liquid-feed direct methanol fuel cell system , 2000 .

[3]  Reddington,et al.  Combinatorial electrochemistry: A highly parallel, optical screening method for discovery of better electrocatalysts , 1998, Science.

[4]  Keith Scott,et al.  Dynamic response of the direct methanol fuel cell under variable load conditions , 2000 .

[5]  M. Kaiser,et al.  Barrier properties of plasma-polymerized thin films , 1999 .

[6]  Thomas F. Fuller,et al.  Mixed-reactant, strip-cell direct methanol fuel cells , 2001 .

[7]  Yasuo Nakajima,et al.  Measurement of methanol crossover in direct methanol fuel cell , 2001 .

[8]  Won Choon Choi,et al.  Modification of proton conducting membrane for reducing methanol crossover in a direct-methanol fuel cell , 2001 .

[9]  Joseph M King,et al.  Applying fuel cell experience to sustainable power products , 2000 .

[10]  Kai Sundmacher,et al.  Dynamics of the direct methanol fuel cell (DMFC): experiments and model-based analysis , 2001 .

[11]  Shimshon Gottesfeld,et al.  Electro‐osmotic Drag of Water in Ionomeric Membranes New Measurements Employing a Direct Methanol Fuel Cell , 1997 .

[12]  A. K. Shukla,et al.  The design and construction of high-performance direct methanol fuel cells. 1. Liquid-feed systems , 1997 .

[13]  Keith Scott,et al.  The effect of operating conditions on the dynamic response of the direct methanol fuel cell , 2000 .