# US 10,374,241 B2 · 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 10,374,241 B2 - Document ID: US10374241B2 - Status: Granted - Kind: B2 - Application number: 15/741,711 - Filed: 2015-07-08 - Published: 2018-07-12 - Granted: 2019-08-06 - Earliest claimed: 2015-07-08 - Assignees: Nissan Motor Co., Ltd. - Applicants: Nissan Motor Co., Ltd. - Inventors: Tatsuya Yaguchi; Motohisa Kamijo - Web page: https://patentgrep.com/patent/US10374241B2 ## CPC - H01M 8/04738: {of auxiliary devices, e.g. reformer, compressor, burner} - H01M 4/86: Inert electrodes with catalytic activity, e.g. for fuel cells - H01M 4/8636: {with a gradient in another property than porosity (H01M4/861 takes precedence)} - H01M 4/8642: {Gradient in composition} - H01M 4/8652: {as mixture} - H01M 8/0618: {Reforming processes, e.g. autothermal, partial oxidation or steam reforming} - H01M 8/0625: {in a modular combined reactor/fuel cell structure} - H01M 8/0637: Direct internal reforming at the anode of the fuel cell - H01M 8/1213: characterised by the electrode/electrolyte combination or the supporting material - H01M 8/1253: the electrolyte containing zirconium oxide - H01M 8/2425: High-temperature cells with solid electrolytes - H01M 8/249: comprising two or more groupings of fuel cells, e.g. modular assemblies - H01M 2004/8684: {Negative electrodes} - H01M 2008/1293: {Fuel cells with solid oxide electrolytes} - Y02E 60/50: Fuel cells - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract The present invention comprises a plurality of fuel cells connected to each other in series, and a reformer configured to reform raw fuel, wherein reformed fuel by the reformer is supplied to a first stage of the plurality of fuel cells, and the fuel cell on the first stage is provided with a methane reaction suppressing function which suppresses reaction of methane included in the reformed fuel to a larger extent than at least one fuel cell on a second and later stages. Suppressing temperature drop due to endothermic reaction in the fuel cell on the first stage can improve the efficiency of electric power generation of the fuel cell system having the plurality of fuel cells arranged in series. ## Claims ### Claim 1 A fuel cell system, comprising: a plurality of fuel cells connected to each other in series; and a reformer configured to reform raw fuel, wherein reformed fuel by the reformer is supplied to a first stage of the plurality of fuel cells, at least one fuel cell in the first stage is provided with a methane reaction suppressing function which suppresses reaction of methane included in the reformed fuel more than at least one fuel cell in a second stage, and the at least one fuel cell in the first stage has an electrode with a smaller area in which fuel and oxidizer react than that of the at least one fuel cell in the second stage. ### Claim 2 A fuel cell system, comprising: a plurality of fuel cells connected to each other in series; and a reformer configured to reform raw fuel, wherein reformed fuel by the reformer is supplied to a first stage of the plurality of fuel cells, at least one fuel cell in the first stage is provided with a methane reaction suppressing function which suppresses reaction of methane included in the reformed fuel more than at least one fuel cell in a second stage, each of the at least one fuel cell in the first stage and the at least one fuel cell in the second stage includes fuel poles configured to form a three-phase interface, and a thickness of the fuel poles of the at least one fuel cell in the first stage is less than a thickness of the fuel poles of the at least one fuel cell in the second stage such that the methane reaction suppressing function of the at least one fuel cell in the first stage suppresses reaction of methane included in the reformed fuel more than the at least one fuel cell in the second stage. ### Claim 3 (depends on 1) The fuel cell system according to claim 1, wherein the at least one fuel cell in the first stage includes a proton conductive material as a material of fuel poles such that the at least one fuel cell in the first stage has the methane reaction suppressing function. ### Claim 4 (depends on 1) The fuel cell system according to claim 1, wherein the at least one fuel cell in the first stage includes a proton conductive material as a material of an electrolyte such that the at least one fuel cell in the first stage has the methane reaction suppressing function. ### Claim 5 (depends on 1) The fuel cell system according to claim 1, wherein the at least one fuel cell in the second stage is provided with a later-stage methane reaction suppressing function which suppresses reaction of methane included in the reformed fuel, and the later-stage methane reaction suppressing function is weaker in terms of a function of suppressing reaction of methane than the methane reaction suppressing function of the at least one fuel cell in the first stage. ### Claim 6 (depends on 5) The fuel cell system according to claim 5, further comprising at least one fuel cell in a third stage after the second stage, wherein the at least one fuel cell in the third stage is provided with a third-stage methane reaction suppressing function which suppresses reaction of methane included in the reformed fuel, the third-stage methane reaction suppressing function is weaker in terms of a function of suppressing reaction of methane than the later-stage methane reaction suppressing function. ### Claim 7 (depends on 1) The fuel cell system according to claim 1, wherein a discharged fuel reformer configured to reform discharged fuel discharged from a fuel cell of a preceding stage is provided between each pair of the plurality of fuel cells. ### Claim 8 (depends on 1) The fuel cell system according to claim 1, wherein the raw fuel is hydrocarbon-based or alcohol-based liquid fuel. ### Claim 9 (depends on 1) The fuel cell system according to claim 1, further comprising a discharged fuel circulator configured to supply, in a circulating manner, the reformer with fuel containing water discharged from a fuel cell located in a last stage of the plurality of fuel cells. ### Claim 10 (depends on 8) The fuel cell system according to claim 8, wherein the alcohol-based liquid fuel contains water. ### Claim 11 (depends on 2) The fuel cell system according to claim 2, wherein the at least one fuel cell in the first stage includes a proton conductive material as a material of the fuel poles such that the at least one fuel cell in the first stage has the methane reaction suppressing function. ### Claim 12 (depends on 2) The fuel cell system according to claim 2, wherein the at least one fuel cell in the first stage includes a proton conductive material as a material of an electrolyte such that the at least one fuel cell in the first stage has the methane reaction suppressing function. ### Claim 13 (depends on 2) The fuel cell system according to claim 2, wherein the at least one fuel cell in the second stage is provided with a later-stage methane reaction suppressing function which suppresses reaction of methane included in the reformed fuel, and the later-stage methane reaction suppressing function is weaker in terms of a function of suppressing reaction of methane than the methane reaction suppressing function of the at least one fuel cell in the first stage. ### Claim 14 (depends on 13) The fuel cell system according to claim 13, further comprising at least one fuel cell in a third stage after the second stage, wherein the at least one fuel cell in the third stage is provided with a third-stage methane reaction suppressing function which suppresses reaction of methane included in the reformed fuel, the third-stage methane reaction suppressing function is weaker in terms of a function of suppressing reaction of methane than the later-stage methane reaction suppressing function. ### Claim 15 (depends on 2) The fuel cell system according to claim 2, wherein a discharged fuel reformer configured to reform discharged fuel discharged from a fuel cell of a preceding stage is provided between each pair of the plurality of fuel cells. ### Claim 16 (depends on 2) The fuel cell system according to claim 2, wherein the raw fuel is hydrocarbon-based or alcohol-based liquid fuel. ### Claim 17 (depends on 2) The fuel cell system according to claim 2, further comprising a discharged fuel circulator configured to supply, in a circulating manner, the reformer with fuel containing water discharged from a fuel cell located in a last stage of the plurality of fuel cells. ### Claim 18 (depends on 16) The fuel cell system according to claim 16, wherein the alcohol-based liquid fuel contains water.