In this study, a membrane electrode assembly(MEA) composed of three electrodes(anode, cathode, and reference electrode) is designed to investigate the effects of methanol concentration on the overpotentials of anode and cathode in direct methanol fuel cells(DMFCs). Using the three-electrode cell, in-situ analyses of the overpotentials are carried out during direct methanol fuel cell operation. It is demonstrated that the three-electrode cell can work effectively in transient state operating condition as well as in steady-state condition, and the anode and cathode exhibit different overpotential curves depending on the concentration of methanol used as fuel. Therefore, from the real-time separation of the anode and cathode overpotentials, it is possible to more clearly prove the methanol crossover effect, and it is expected that in-situ analysis using the three-electrode cell will provide an opportunity to obtain more diverse results in the area of fuel cell research.

In this paper, a structural integrity on the test rig with assembly plug to perform intermediate examination is evaluated. Structural analysis results between the test rig with non assembly plug and assembly plug are compared, because the assembly plug has an effect on the flow of the coolant in the test rig. A equivalent stress value on the test rig with assembly plug is increased more than the stress on the test rig with non-assembly plug. A shape optimization of the assembly plug is performed to decrease the stress. Considering a connection with the transport tool, a optimized shape of the assembly plug is presented to minimize the stress on the test rig. Using the optimized assembly plug, the equivalent stress on the test rig with the optimized plug is less than the stress on the test rig with the non-optimized plug.