Abstract
The passive type PEFC tends to suffer from sudden power breakdown in a long time continuous operation, and the hydrogen circulating system using pressure difference is effective as a countermeasure. In this study, some properties were experimentally measured using a rated 55 W fuel cell module with the hydrogen circulating system during a constant current operation. And the relationship between the properties, such as the output voltage of the fuel cell, the temperature of the module body and the temperature and humidity of hydrogen and air, was investigated. As a result, the water balance in the fuel cell and the behavior of generated liquid water, which probably caused output voltage fluctuation, were discussed.
