Fuel cell system, and operating method of fuel cell system

An operating method of a fuel cell system, the fuel cell system comprising:

• a membrane electrode assembly having an anode electrode joined to one surface of a solid polymer electrolyte membrane and a cathode electrode joined to other surface of a solid polymer electrolyte membrane;
• an anode-side internal passage facing the anode electrode of the membrane electrode assembly;
• a cathode-side internal passage facing the cathode electrode of the membrane electrode assembly;
• a hydrogen supply section configured to supply hydrogen gas to the anode-side internal passage;
• an oxygen supply section configured to supply oxygen gas to the cathode-side internal passage;
• and
• a control device configured to control a flow of the oxygen gas in the oxygen supply section, wherein the fuel cell system being configured to generate electric power using an electrochemical reaction between hydrogen and oxygen passing through the membrane electrode assembly,
• the oxygen supply section comprising:
• a gas circulation passage comprising a first passage section connected to a first end of the cathode-side internal passage and a second passage section connected to a second end of the cathode-side internal passage, wherein the first passage section and the second passage section are connected;
• an oxygen supply source connected to the gas circulation passage;
• and
• a gas circulation device located in the second passage section, comprising a pump device operable in a forward gas feed direction and a reverse gas feed direction, and configured to circulate and flow the oxygen gas in at least one of:
• a first direction heading towards the first end of the cathode-side internal passage from the first passage section, or a second direction heading towards the second end of the cathode-side internal passage from the second passage section, in the gas circulation passage;
• and
• the operating method of the fuel cell system comprising switching a flow of the oxygen gas flowing through the gas circulation passage in a reverse direction according to a distribution state of moisture at the cathode electrode of the membrane electrode assembly.

A fuel cell system comprising:

• a membrane electrode assembly having an anode electrode joined to one surface of a solid polymer electrolyte membrane and a cathode electrode joined to other surface of the solid polymer electrolyte membrane;
• an anode-side internal passage facing the anode electrode of the membrane electrode assembly;
• a cathode-side internal passage facing the cathode electrode of the membrane electrode assembly;
• a hydrogen supply section configured to supply hydrogen gas to the anode-side internal passage;
• an oxygen supply section configured to supply oxygen gas to the cathode-side internal passage;
• a control device configured to control a flow of the oxygen gas in the oxygen supply section;
• a power generation quantity detection unit configured to detect an accumulated power generation quantity from a reference timing point;
• a generated water storage tank provided in the gas circulation passage and configured to store the generated water flowing out of the cathode-side internal passage;
• and
• a generated water quantity detection device configured to detect a flow rate of the generated water stored in the generated water storage tank, and
• wherein, the fuel cell system is configured to generate electric power using an electrochemical reaction between hydrogen and oxygen passing through the membrane electrode assembly,
• wherein the oxygen supply section comprises:
• a gas circulation passage connected to a first end of the cathode-side internal passage and a second end of the cathode-side internal passage;
• an oxygen supply source connected to the gas circulation passage;
• and
• a gas circulation device located in the second passage section and configured to be operable in a forward gas feed direction and a reverse gas feed direction, and configured to circulate and flow the oxygen gas in at least one of:
• a first direction heading towards the first end of the cathode-side internal passage from the first passage section, or a second direction heading towards the second end of the cathode-side internal passage from the second passage section, in the gas circulation passage;
• and
• wherein the control device switches flow of the oxygen gas by the gas circulation device from the first flow direction and the second flow direction according to a distribution state of moisture at the cathode electrode of the membrane electrode assembly, wherein the control device switches the flow direction of oxygen gas by the gas circulation device when a difference between a quantity of the generated water estimated from an accumulated power generation quantity detected by the power generation quantity detection unit and the generated water quantity detected by the generated water quantity detection device is equal or greater than a threshold amount.