TY - JOUR
T1 - Operational characteristics of the direct methanol fuel cell stack on fuel and energy efficiency with performance and stability
AU - Park, Jun Young
AU - Seo, Yongho
AU - Kang, Sangkyun
AU - You, Daejong
AU - Cho, Hyejung
AU - Na, Youngseung
PY - 2012/4
Y1 - 2012/4
N2 - This paper is presented to investigate operational characteristics of a direct methanol fuel cell (DMFC) stack with regard to fuel and energy efficiency, including its performance and stability under various operating conditions. Fuel efficiency of the DMFC stack is strongly dependent on fuel concentration, working temperature, current density, and anode channel configuration in the bipolar plates and noticeably increases due to the reduced methanol crossover through the membrane, as the current density increases and the methanol concentration, anode channel depth, and temperature decreases. It is, however, revealed that the energy efficiency of the DMFC stack is not always improved with increased fuel efficiency, since the reduced methanol crossover does not always indicate an increase in the power of the DMFC stack. Further, a lower methanol concentration and temperature sacrifice the power and operational stability of the stack with the large difference of cell voltages, even though the stack shows more than 90% of fuel efficiency in this operating condition. The energy efficiency is therefore a more important characteristic to find optimal operating conditions in the DMFC stack than fuel efficiency based on the methanol utilization and crossover, since it considers both fuel efficiency and cell electrical power. These efforts may contribute to commercialization of the highly efficient DMFC system, through reduction of the loss of energy and fuel.
AB - This paper is presented to investigate operational characteristics of a direct methanol fuel cell (DMFC) stack with regard to fuel and energy efficiency, including its performance and stability under various operating conditions. Fuel efficiency of the DMFC stack is strongly dependent on fuel concentration, working temperature, current density, and anode channel configuration in the bipolar plates and noticeably increases due to the reduced methanol crossover through the membrane, as the current density increases and the methanol concentration, anode channel depth, and temperature decreases. It is, however, revealed that the energy efficiency of the DMFC stack is not always improved with increased fuel efficiency, since the reduced methanol crossover does not always indicate an increase in the power of the DMFC stack. Further, a lower methanol concentration and temperature sacrifice the power and operational stability of the stack with the large difference of cell voltages, even though the stack shows more than 90% of fuel efficiency in this operating condition. The energy efficiency is therefore a more important characteristic to find optimal operating conditions in the DMFC stack than fuel efficiency based on the methanol utilization and crossover, since it considers both fuel efficiency and cell electrical power. These efforts may contribute to commercialization of the highly efficient DMFC system, through reduction of the loss of energy and fuel.
KW - Direct methanol fuel cell
KW - Energy efficiency
KW - Fuel efficiency
KW - Methanol crossover
KW - Stability
KW - Stack
UR - http://www.scopus.com/inward/record.url?scp=84858281031&partnerID=8YFLogxK
U2 - 10.1016/j.ijhydene.2011.12.066
DO - 10.1016/j.ijhydene.2011.12.066
M3 - Article
AN - SCOPUS:84858281031
SN - 0360-3199
VL - 37
SP - 5946
EP - 5957
JO - International Journal of Hydrogen Energy
JF - International Journal of Hydrogen Energy
IS - 7
ER -