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EP-4742334-A1 - FUEL CELL SYSTEM

EP4742334A1EP 4742334 A1EP4742334 A1EP 4742334A1EP-4742334-A1

Abstract

A first fuel cell system (10) includes a fuel cell (21) that generates electric power with a reaction between fuel gas supplied to a fuel electrode and oxidant gas supplied to an oxidant electrode, a combustor (22) that combusts combustible gas, a plurality of heat exchangers, each of which includes a low-temperature gas channel through which low-temperature gas flows, the low temperature gas being fuel gas supplied to the fuel cell (21) or oxidant gas, and a high-temperature gas channel through which high-temperature gas flows, the high-temperature gas being off-gas discharged from the fuel cell (21) or combustion exhaust gas discharged from the combustor (22), and exchanges heat between low-temperature gas flowing through the low-temperature gas channel and high-temperature gas flowing through the high-temperature gas channel, and a case (39) having a thermal insulation property and housing the fuel cell (21), the combustor (22), and the plurality of heat exchangers, in which the fuel cell (21) and the combustor (22) are disposed in a central portion in an internal space of the case (39), and one or more heat exchangers of the plurality of heat exchangers are disposed so as to cover at least a portion of the fuel cell (21) and the combustor (22) from outside.

Inventors

  • WATANABE, HIDETAKA
  • FUJIRAI, Masayuki
  • FUNAYAMA, Honami

Assignees

  • AISIN CORPORATION

Dates

Publication Date
20260513
Application Date
20251027

Claims (7)

  1. A fuel cell system (10) comprising: a fuel cell (21) configured to generate electric power with a reaction between fuel gas supplied to a fuel electrode and oxidant gas supplied to an oxidant electrode; a combustor (22) for combusting combustible gas; a plurality of heat exchangers, each of which includes a low-temperature gas channel for flowing therethrough low-temperature gas, the low-temperature gas being fuel gas supplied to the fuel cell (21) or oxidant gas, and a high-temperature gas channel for flowing therethrough high-temperature gas, the high-temperature gas being off-gas discharged from the fuel cell (21) or combustion exhaust gas discharged from the combustor (22), and is configured to exchange heat between low-temperature gas flowing through the low-temperature gas channel and high-temperature gas flowing through the high-temperature gas channel; and a case (39) having a thermal insulation property and housing the fuel cell (21), the combustor (22), and the plurality of heat exchangers, wherein the fuel cell (21) and the combustor (22) are disposed in a central portion in an internal space of the case (39), and one or more heat exchangers of the plurality of heat exchangers are disposed so as to cover at least a portion of the fuel cell (21) and the combustor (22) from outside.
  2. The fuel cell system (10) according to Claim 1, wherein the one or more heat exchangers are arranged on upper side and/or a side of the fuel cell (21).
  3. The fuel cell system (10) according to any one of Claims 1 or 2, wherein one or more other heat exchangers of the plurality of heat exchangers are disposed so as to further cover at least a portion of the one or more heat exchangers from outside.
  4. The fuel cell system (10) according to Claim 3, wherein the plurality of heat exchangers includes a first heat exchanger (31) that includes a fuel gas channel (31a, 133a, 134a, 231a) for flowing therethrough the fuel gas as the low-temperature gas and a first combustion exhaust gas channel (31b, 131b, 231b) for flowing therethrough the combustion exhaust gas flows as the high-temperature gas, and configured to exchange heat between fuel gas flowing through the fuel gas channel (31a, 133a, 134a, 231a) and combustion exhaust gas flowing through the first combustion exhaust gas channel (31b, 131b, 231b), a second heat exchanger (32) that includes a first oxidant gas channel (32a, 132a, 232a) for flowing therethrough the oxidant gas as the low-temperature gas and a second combustion exhaust gas channel (32b, 132b) for flow therethrough the combustion exhaust gas that has passed through the first heat exchanger (31) as the high-temperature gas, and is configured to exchange heat between oxidant gas flowing through the first oxidant gas channel (32a, 132a, 232a) and combustion exhaust gas flowing through the second combustion exhaust gas channel (32b, 132b), and a third heat exchanger (33) that includes a second oxidant gas channel (33a) for flowing therethrough the oxidant gas that has passed through the second heat exchanger (32) as the low-temperature gas and an off-gas channel (33b, 133b, 134b, 232b) for flowing therethrough the fuel off-gas or oxidant off-gas as the high-temperature gas, and is configured to exchange heat between oxidant gas flowing through the second oxidant gas channel (33a) and the fuel off-gas or the oxidant off-gas flowing through the off-gas channel (33b, 133b, 134b, 232b), the one or more heat exchangers are the first heat exchanger (31) and the third heat exchanger (33), and the one or more other heat exchangers is the second heat exchanger (32).
  5. The fuel cell system (10) according to Claim 4, further comprising: a fuel gas supply line for supplying the fuel gas to the fuel electrode; a condenser (62) that is disposed outside the case (39) and is configured to condense water vapor contained in the fuel off-gas; a fuel off-gas supply line for supplying the fuel off-gas to the condenser (62); a recirculation line for recirculating a portion of the fuel off-gas that has passed through the condenser (62) to the fuel gas supply line; a fuel supply line for combustion that is configured to supply another portion of the fuel off-gas that has passed through the condenser (62) to the combustor (22); and an oxidant off-gas supply line that is configured to supply oxidant off-gas discharged from the oxidant electrode to the combustor (22), wherein the third heat exchanger (33) includes a fuel off-gas channel (33b, 133b, 134b, 232b) for flowing therethrough the fuel off-gas as the high-temperature gas, and is configured to exchange heat between oxidant gas flowing through the second oxidant gas channel (33a) and the fuel off-gas flowing through the fuel off-gas channel (33b, 133b, 134b, 232b), and the fuel off-gas supply line is configured to supply fuel off-gas that has passed through the third heat exchanger (33) to the condenser (62).
  6. The fuel cell system (10) according to any one of Claims 1 to 5, wherein the one or more heat exchangers are arranged so as to cover, in combination with a heat insulation material (34, 35, 36, 37, 38a, 38b), at least a portion of the fuel cell (21) and the combustor (22).
  7. The fuel cell system (10) according to any one of Claims 3 to 6, wherein the one or more another heat exchangers are arranged so as to cover, in combination with a heat insulation material (34, 35, 36, 37, 38a, 38b), the one or more heat exchangers.

Description

TECHNICAL FIELD The present disclosure discloses a fuel cell system. BACKGROUND DISCUSSION Conventionally, there is provided a fuel cell device including a fuel cell that generates electric power utilizing air for power generation and reformed gas, a combustor that combusts both off-gas of the reformed gas and off-gas of the air for power generation discharged from the fuel cell, a first air heat exchanger that has a combustion exhaust gas path through which combustion exhaust gas generated in the combustor flows and a first air supply path through which the air for power generation flows, and that heats the air for power generation by heat exchange between the combustion exhaust gas and the air for power generation, a fuel cell storage which stores the fuel cell, and through which the off-gas of the air for power generation discharged from the fuel cell flows, a second air heat exchanger that has a second air supply path which supplies the air for power generation, which has flowed through the first air supply path, to the fuel cell, and that heats the air for power generation by heat exchange between the off-gas of the air for power generation which flows in the fuel cell storage and the air for power generation which flows through the second air supply path, and a housing that stores members, in which the first air supply path and the second air supply path are disposed to cover whole members stored in the housing (refer to Japanese Unexamined Patent Application Publication No. 2017-199658, for example). It is described that, according to the fuel cell device, it is possible to reduce an amount of heat radiation to outside and facilitate temperature control of the air for power generation and component units included in the fuel cell device. In the fuel cell system described above, the air supply paths (the first air supply path and the second air supply path) cover the whole members stored in the housing, which is, however, insufficient to reduce the heat radiation to outside of the housing, and thus may cause low power generation efficiency. A need thus exists for a fuel cell system which is not susceptible to the drawback mentioned above. A main object of the present disclosure is to sufficiently reduce heat dissipation to outside of a case to further improve power generation efficiency. SUMMARY The present disclosure has adopted the following aspects to achieve the main object described above. That is, a gist of a first fuel cell system of the present disclosure is that the first fuel cell system includes a fuel cell that generates electric power with a reaction between fuel gas supplied to a fuel electrode and oxidant gas supplied to an oxidant electrode, a combustor that combusts combustible gas, a plurality of heat exchangers, each of which includes a low-temperature gas channel through which low-temperature gas flows, the low temperature gas being fuel gas supplied to the fuel cell or oxidant gas, and a high-temperature gas channel through which high-temperature gas flows, the high-temperature gas being off-gas discharged from the fuel cell or combustion exhaust gas discharged from the combustor, and exchanges heat between low-temperature gas flowing through the low-temperature gas channel and high-temperature gas flowing through the high-temperature gas channel, and a case having a thermal insulation property and housing the fuel cell, the combustor, and the plurality of heat exchangers, in which the fuel cell and the combustor are disposed in a central portion in an internal space of the case, and one or more heat exchangers of the plurality of heat exchangers are disposed so as to cover at least a portion of the fuel cell and the combustor from outside. In the first fuel cell system of the present disclosure, the fuel cell and the combustor are disposed in the central portion in the internal space of the case, and one or more heat exchangers of the plurality of heat exchangers are disposed so as to cover at least a portion of the fuel cell and the combustor from the outside. As a result, it is possible to transfer heat of the fuel cell and the combustor, which are high-temperature members disposed in the central portion, to members (one or more of the heat exchangers) disposed outside, and reduce heat dissipation from the high-temperature members. As a result, the heat dissipation to the outside of the case can be sufficiently reduced, and the power generation efficiency can be further improved. A gist of a second fuel cell system of the present disclosure is that the second fuel cell system includes a fuel cell that generates electric power with a reaction between fuel gas supplied to a fuel electrode and oxidant gas supplied to an oxidant electrode, a combustor that combusts combustible gas, a plurality of heat exchangers, each of which includes, in different combinations, a low-temperature gas channel through which low-temperature gas flows, the low temperature gas being fuel gas supplied t