Fuel cell system and related startup method

A fuel cell system comprising:

• a fuel cell having a fuel electrode and an oxidizer electrode, disposed in opposition thereto, between which an electrolyte membrane is sandwiched;
• supplying means for supplying fuel gas to the fuel cell through a fuel gas supply passage;
• discharging means for discharging the fuel gas, discharged from the fuel cell, to an outside of the fuel cell system;
• controlling means for controlling fuel gas substituting treatment such that, during startup of the fuel cell system, the fuel gas is discharged outside the fuel cell system through the discharging means while supplying the fuel gas so as to cause a state quantity of the fuel gas, to be supplied to the fuel cell from the supplying means, to be constant for thereby allowing the fuel gas supply passage and the fuel electrode to be substituted with the fuel gas;
• and
• a purge means for discharging at least a portion of the fuel gas, discharged from the fuel cell, outside the fuel cell during operation of the fuel cell system,
• wherein the discharging means has a laraer opening area than the purge means.

A method of substituting fuel gas in a fuel cell system which includes a fuel cell having a fuel electrode and an oxidizer electrode, disposed in opposition thereto, between which an electrolyte membrane is sandwiched, the method comprising:

• supplying fuel gas to the fuel cell through a fuel gas supply passage;
• discharging the fuel gas, discharged from the fuel cell, to an outside of the fuel cell system via a fuel gas discharge section;
• and
• executing fuel gas substituting treatment such that, during startup of the fuel cell system, the fuel gas is discharged outside the fuel cell system while supplying the fuel gas so as to cause a state quantity of the fuel gas, to be supplied to the fuel cell, to be constant for thereby allowing the fuel gas supply passage and the fuel electrode to be substituted with the fuel gas, wherein
• at least a portion of the fuel gas, discharged from the fuel cell, is discharged outside the fuel cell during operation of the fuel cell system via a purge section, and
• the fuel gas discharge section has a larger opening area than the purge section.

A fuel cell system comprising:

• a fuel cell having a fuel electrode and an oxidizer electrode, disposed in opposition thereto, between which an electrolyte membrane is sandwiched;
• a fuel gas supply source adapted to supply fuel gas to the fuel cell through a fuel gas supply passage;
• a fuel gas discharge section adapted to discharge the fuel gas, discharged from the fuel cell, to an outside of the fuel cell system;
• and
• a control section adapted to execute fuel gas substituting treatment such that, during startup of the fuel cell system, the fuel gas is discharged outside the fuel cell system through the fuel gas discharge section while supplying the fuel gas so as to cause a state quantity of the fuel gas, to be supplied to the fuel cell from the fuel gas supply source, to be constant for thereby allowing the fuel gas supply passage and the fuel electrode to be substituted with the fuel gas;
• and
• a purge section adapted to discharge at least a portion of the fuel gas, discharged from the fuel cell, outside the fuel cell during operation of the fuel cell system,
• wherein the fuel gas discharge section has a laraer opening area than the purge section.