5 8

0 2,000 4,000 6,000 8,000 Operation time [h] Fig.4 Results of the diagnostic test (variety of the light load performance)

0 2,000 4,000 6,000 8,000 Operation time [h]

Fig.5 Results of the diagnostic test (variety of cathode diffusive state)

(3)Influence of the perturbation

Figure 6 shows the results of weekly load perturbation test, the decay rate showed 2.9mV/Kh in this term. As for the decay rate of daily load perturbation test were less than weekly one, 1.4mV/Kh,shown in Fig.7. The supposed reasons are fol|piy.

• Because of the motive force on the electrolyte moving from cathode to anode by the ionic mobility during rate load(high current density) operation, the electrolyte adsorbed in the cathode would be got out and the electrode effective surface area and cell performance must be reduced.

• In the standby(low current density) operation, the motive force would become so weaker that the moved electrolyte would be recycled back to cathode and be adsorbed again, and cell performance must be recovered.

• It is considered that daily perturbation would be often recovering the cell performance, the appeared decay rate might be seemed lower.

• Although the decay rate of the daily perturbation is seemed lower than weekly's as in the short term, the low rate(1.5mV/Kh) has been obtained in the continuous operation term until then, thus the reducing of the cell performance with the electrolyte moving would be settled down and the influence would be reduced during the long term operation.

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