# US 2004/0072052 A1 · Exhaust gas processing device for fuel cell > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2004/0072052 A1 - Document ID: US20040072052A1 - Status: Published application - Kind: A1 - Application number: 10/678,820 - Filed: 2003-10-03 - Published: 2004-04-15 - Earliest claimed: 2002-10-03 - Assignees: Honda Motor Co., Ltd. - Inventors: Akio Yamamoto; Kazunori Fukuma; Takatsugu Koyama; Hideo Numata; Masahiro Matsutani - Web page: https://patentgrep.com/patent/US20040072052A1 ## CPC - H01M 8/04223: during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells - H01M 8/04302: applied during start-up - H01M 8/043: applied during specific periods - H01M 8/0662: Treatment of gaseous reactants or gaseous residues, e.g. cleaning - H01M 8/04097: {with recycling of the reactants (H01M8/04119, H01M8/04104 take precedence)} - H01M 8/04208: {Cartridges, cryogenic media or cryogenic reservoirs} - H01M 2250/30: Fuel cells in portable systems, e.g. mobile phone, laptop - Y02B 90/10: Applications of fuel cells in buildings - Y02E 60/50: 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 ## Abstract Hydrogen gas supplied to and then purged from a fuel cell is temporarily retained in a reservoir provided in an exhaust fuel diluter, and diluted before release into atmosphere. Cathode exhaust gas discharged from a cathode of the fuel cell is mixed to dilute the hydrogen gas, and air continues to be supplied to the cathode of the fuel cell for a specific period of time even after generation of electric power in the fuel cell is stopped, so that the hydrogen gas retained in the reservoir is continuously diluted with the cathode exhaust gas and released. Air for ventilation of the fuel cell may be used instead or in addition, to dilute and release the hydrogen gas retained in the reservoir after the generation of electric power in the fuel cell is stopped. ## Claims ### Claim 1 An exhaust gas processing device for a fuel cell, in which the fuel cell is supplied with air and hydrogen gas to generate electric power, comprising: a reservoir that retains the hydrogen gas purged from the fuel cell, wherein the hydrogen gas retained in the reservoir is diluted and released into atmosphere even after generation of electric power in the fuel cell is stopped. ### Claim 2 (depends on 1) An exhaust gas processing device according to claim 1, wherein the hydrogen gas retained in the reservoir is mixed and diluted with cathode exhaust gas discharged from a cathode of the fuel cell before the hydrogen gas is released into the atmosphere; and wherein air continues to be supplied to the cathode of the fuel cell so that the hydrogen gas retained in the reservoir is released together with the cathode exhaust gas, after the generation of electric power in the fuel cell is stopped. ### Claim 3 (depends on 2) An exhaust gas processing device according to claim 2, wherein the air continues to be supplied to the cathode of the fuel cell for a specific period of time after the generation of electric power in the fuel cell is stopped; and wherein the specific period of time expires when a predetermined period of time elapses and/or when a concentration of hydrogen in the reservoir decreases to a predetermined value or smaller. ### Claim 4 (depends on 1) An exhaust gas processing device according to claim 1, further comprising: a hydrogen relief valve that is connected to the reservoir, wherein when the generation of electric power in the fuel cell is stopped, the hydrogen relief valve is opened and air for ventilation of the fuel cell is supplied to a passage connected to the hydrogen relief valve. ### Claim 5 (depends on 4) An exhaust gas processing device according to claim 4, wherein the air for ventilation of the fuel cell continues to be supplied to the passage for a specific period of time after the generation of electric power in the fuel cell is stopped; and wherein the specific period of time expires when a predetermined period of time elapses and/or when a concentration of hydrogen in the reservoir decreases to a predetermined value or smaller. ### Claim 6 (depends on 4) An exhaust gas processing device according to claim 4, further comprising a hydrogen sensor provided downstream of the passage, to detect a breakdown of the hydrogen relief valve during the generation of electric power in the fuel cell. ### Claim 7 An exhaust gas processing device for a fuel cell, in which the fuel cell is supplied with air and hydrogen gas to generate electric power and the hydrogen gas discharged from an anode of the fuel cell is recirculated in a hydrogen recirculation piping system, comprising: a reservoir in which hydrogen gas purged from the hydrogen recirculation piping system is retained; a cathode exhaust gas pipe that is connected to a cathode of the fuel cell and provided with holes through which the hydrogen gas retained in the reservoir is sucked in so that the hydrogen gas is diluted with cathode exhaust gas and released into atmosphere; and a blower that supplies air to the cathode of the fuel cell and forces the air discharged from the cathode of the fuel cell to flow through the cathode exhaust gas pipe, wherein the hydrogen gas retained in the reservoir is diluted and released into the atmosphere even after generation of electric power in the fuel cell is stopped. ### Claim 8 (depends on 7) An exhaust gas processing device according to claim 7, wherein the blower continues to supply air to the cathode of the fuel cell to dilute and release the hydrogen gas after the generation of electric power in the fuel cell is stopped. ### Claim 9 (depends on 8) An exhaust gas processing device according to claim 8, wherein the blower continues to supply air to the cathode of the fuel cell for a specific period of time after the generation of electric power in the fuel cell is stopped; and wherein the specific period of time expires when a predetermined period of time elapses and/or when a concentration of hydrogen in the reservoir decreases to a predetermined value or smaller. ### Claim 10 (depends on 7) An exhaust gas processing device according to claim 7, further comprising: a hydrogen relief valve that is connected to the reservoir; and a ventilator that supplies air for ventilation of the fuel cell, wherein when the generation of electric power in the fuel cell is stopped, the hydrogen relief valve is opened and the ventilator supplies air for ventilation of the fuel cell and forces the air for ventilation of the fuel cell to flow through a passage connected to the hydrogen relief valve. ### Claim 11 (depends on 10) An exhaust gas processing device according to claim 10, wherein the ventilator continues to supply the air for ventilation of the fuel cell to the passage for a specific period of time after the generation of electric power in the fuel cell is stopped; and wherein the specific period of time expires when a predetermined period of time elapses and/or when a concentration of hydrogen in the reservoir decreases to a predetermined value or smaller. ### Claim 12 (depends on 10) An exhaust gas processing device according to claim 10, further comprising a hydrogen sensor provided downstream of the passage, to detect a breakdown of the hydrogen relief valve during the generation of electric power in the fuel cell.