Title :
Development of a 150-watt direct methanol fuel cell system
Author :
Valdez, T.I. ; Narayanan, S.R. ; Rohatgi, N.
Author_Institution :
Jet Propulsion Lab., California Inst. of Technol., Pasadena, CA, USA
Abstract :
Stack development for a Nafion(R) based 150-watt direct methanol fuel cell (DMFC) system is discussed in this paper. Single cell data for a membrane electrode assembly (MEA) that can operate at low air stoichiometry is presented. The stack operating conditions for achieving a water balance have been determined to be 55/spl deg/C 0.5 M MeOH at a maximum of 1.75 times air stoichiometry at 100 mA/cm/sup 2/. Single cells with a 25-cm/sup 2/ active area have been operated in this regime and can maintain an average cell voltage of 0.43 V at 100 mA/cm/sup 2/ for 120 minutes with a cell voltage decay of 0.2 mV/min. A five-cell stack with a 80-cm/sup 2/ active area, scaled up from the single cell, was capable of sustaining 100-mA/cm/sup 2/ load at a 1.75 air stoichiometry for over 70 hours, with a voltage decay of the order of 2 mV/hr. Voltage decay is reversible by purging excess water in the cathode.
Keywords :
cathodes; electrochemical electrodes; membranes; proton exchange membrane fuel cells; 0.43 V; 120 min; 150 W; 55 C; Nafion; cathode; cell voltage decay; direct methanol fuel cell system; excess water purging; low air stoichiometry; membrane electrode assembly; reversible voltage decay; stack development; stack operating conditions; water balance; Biomembranes; Cathodes; Drives; Electrodes; Fuel cells; Humidity; Methanol; Propulsion; Testing; Voltage;
Conference_Titel :
Battery Conference on Applications and Advances, 2000. The Fifteenth Annual
Conference_Location :
Long Beach, CA, USA
Print_ISBN :
0-7803-5924-0
DOI :
10.1109/BCAA.2000.838368
