The general GDL thickness dGDL is around 0.3 mm and the
diffusivity Deff
g of porous GDL is 10e5 m2
/s, the time constant
tK is of the order of 0.01 s [25].
Fig. 6 shows that the effect of different vibration frequency
on transient response of PEMFC at 4 mm amplitude and
905 smL/min air flow rate. It can be seen that when the load
changes, the voltage decreases continuously until it reaches
the minimum level, then the voltage overshoot and reaches
the new steady-state level. It is important to note that the
voltage fluctuation under vibration frequency at 20 Hz is
greater as compared with the vibration frequency at 10 Hz and
no vibration. This may be because vibration causes water to
fluctuation in gas diffusion layer, which interferes with the
mass-transfer process. In addition, when the voltage reaches
new the steady-state, there is a negligible change under