# US 2010/0167174 A1 · Fuel cell system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0167174 A1 - Document ID: US20100167174A1 - Status: Published application - Kind: A1 - Application number: 12/377,867 - Filed: 2007-11-28 - Published: 2010-07-01 - Earliest claimed: 2006-12-01 - Assignees: Toyota Jidosha Kabushiki Kaisha - Inventors: Sho Usami - Web page: https://patentgrep.com/patent/US20100167174A1 ## CPC - H01M 8/04761: {of fuel cell exhausts} - H01M 8/0234: Carbonaceous material - H01M 8/04179: {by purging or increasing flow or pressure of reactants} - H01M 8/04231: {Purging of the reactants} - H01M 8/04559: {of fuel cell stacks} - H01M 8/04798: {of fuel cell reactants} - H01M 8/04141: {by water containing exhaust gases} - H01M 8/0488: {of fuel cell stacks} - H01M 2004/8689: {Positive electrodes} - H01M 2008/1095: {Fuel cells with polymeric electrolytes} - H01M 2250/10: Fuel cells in stationary systems, e.g. emergency power source in plant - H01M 2250/20: Fuel cells in motive systems, e.g. vehicle, ship, plane - Y02B 90/10: Applications of fuel cells in buildings - Y02E 60/50: Fuel cells - Y02T 90/40: Application of hydrogen technology to transportation, e.g. using fuel cells - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract Provided is a fuel cell system using the dead end method and capable of exhausting impurities accumulated at the anode side while suppressing the oxidization of carbon. In the fuel cell system (1), a fuel cell (2) is operated in the state that the fuel off gas flow path (8) is closed. When q purge valve (9) is opened, impurities accumulated in the flow path (8) are exhausted. If the cell voltage measured by voltage measuring means (11) exceeds a predetermined value, purge limit means (13) is operated so that no purge is performed. Here, if it is assumed that X is the cathode potential at which carbon is oxidized and Y is the maximum value of the anode potential, the predetermined value can be defined as (X−Y). ## Claims ### Claim 1 A fuel cell system that has a fuel cell containing an anode and a cathode, which are positioned on either side of an electrolyte membrane, supplies a fuel gas to the anode, supplies an oxidant gas to the cathode, and operates while a passage for a fuel off gas discharged from the fuel cell is closed, carbon being used for a side toward the cathode, the fuel cell system comprising: voltage measurement means for measuring a voltage of the fuel cell; purge means for performing a purge by opening the passage for the fuel off gas; and purge limitation means for limiting an operation of the purge means when the voltage measured by the voltage measurement means is not lower than a predetermined value. ### Claim 2 (depends on 1) The fuel cell system according to claim 1, wherein, when a potential of the cathode at which the carbon oxidizes is X and a maximum value of a potential of the anode is Y, the predetermined value is equal to X−Y. ### Claim 3 (depends on 2) The fuel cell system according to claim 2, wherein the value X is between 1.1 V and 1.3 V; and wherein the value Y is between 0.45 V and 0.55 V. ### Claim 4 (depends on 2) The fuel cell system according to claim 2, wherein the value X is 1.2 V. ### Claim 5 (depends on 1) The fuel cell system according to claim 1, wherein the predetermined value is 0.7 V. ### Claim 6 (depends on 1) The fuel cell system according to claim 1, further comprising: voltage decrease means for decreasing the voltage of the fuel cell when the voltage measured by the voltage measurement means is not lower than the predetermined value. ### Claim 7 (depends on 6) The fuel cell system according to claim 6, wherein the voltage decrease means sets a current in the fuel cell to a maximum value of a permissible current in the fuel cell. ### Claim 8 (depends on 6) The fuel cell system according to claim 6, wherein the voltage decrease means sets a pressure of the fuel gas to a minimum pressure required for the purge. ### Claim 9 A fuel cell system that has a fuel cell containing an anode and a cathode, which are positioned on either side of an electrolyte membrane, supplies a fuel gas to the anode, supplies an oxidant gas to the cathode, and in at least a particular operation mode, operates while a passage for a fuel off gas discharged from the fuel cell is closed, carbon being used for a side toward the cathode, the fuel cell system comprising: purge means for performing a purge by opening the passage for the fuel off gas; and purge limitation means for limiting an operation of the purge means so that an amount of purge decreases as oxidation of the carbon progresses. ### Claim 10 (depends on 9) The fuel cell system according to claim 9, wherein the purge limitation means limits an operation of the purge means so that the amount of purge decreases with an increase in an amount of carbon dioxide generation in the cathode. ### Claim 11 A fuel cell system that has a fuel cell containing an anode and a cathode, which are positioned on either side of an electrolyte membrane, supplies a fuel gas to the anode, supplies an oxidant gas to the cathode, and operates while a passage for a fuel off gas discharged from the fuel cell is closed, carbon being used for a side toward the cathode, the fuel cell system comprising: a voltage measurement device for measuring a voltage of the fuel cell; a purge device for performing a purge by opening the passage for the fuel off gas; and a purge limitation device for limiting an operation of the purge device when the voltage measured by the voltage measurement device is not lower than a predetermined value.