SECONDARY BATTERY TYPE FUEL CELL SYSTEM

This secondary battery type fuel cell system is provided with a hydrogen generator (1) that generates hydrogen by an oxidation reaction with water and is capable of regeneration by a reduction reaction with hydrogen and a SOFC (5) having an electricity generating function and a water electrolysis function. The system circulates a gas containing hydrogen and water vapor between the hydrogen generation part (1) and SOFC (5). Also provided is a water vapor partial pressure ratio setting section (heater (2), temperature sensor (3), and controller (7)) that sets the water vapor partial pressure ratio for the hydrogen generator (1).