Electrochemical reaction module

Abstract

To prevent an excessive increase in the temperature of a generator.SOLUTION: An electrochemical reaction module comprises: an electrochemical reaction cell stack that includes single cells each including a fuel electrode, an electrolyte layer, and an air electrode, and has a first gas circulation space that the fuel electrode faces, and a second gas circulation space that the air electrode faces; a generator that generates first gas to be supplied to the first gas circulation space; a burner that burns gas for burning and heats the generator with heat of burning; and a container that accommodates the generator and the burner. The burner has a blowout surface in which a blowout port opens from which the gas for burning blows out. The blowout surface does not directly face the generator.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The technology disclosed in this specification relates to an electrochemical reaction module.

Background Art

[0002] A fuel cell module including a fuel cell stack and a fluid supply device that shares fuel gas with the fuel cell stack is known. The fluid supply device includes a reformer for generating fuel gas to be supplied to the fuel cell stack and a combustor for heating the reformer. Air, which is an oxidant gas for power generation, is also supplied from the outside to the fluid supply device, heated by the combustor, and supplied to the fuel cell stack in a high-temperature state (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above fuel cell module, if the firepower of the combustor is increased in an attempt to sufficiently heat the fuel gas and the oxidant gas, there is a concern that the members constituting the reformer may be deformed or damaged by heat.

[0005] Such a problem is a common problem also in a module including an electrolytic cell stack including a plurality of electrolytic cell units that are constituent units of a solid oxide type electrolytic cell (hereinafter referred to as "SOEC") that generates hydrogen using an electrolysis reaction of water. Further, such a problem is a common problem not only in SOFC and SOEC but also in modules including other types of electrochemical reaction cell stacks.

[0006] This specification discloses a technology capable of solving the above-described problems.

Means for Solving the Problem

[0007] (1) The electrochemical reaction module disclosed by this specification includes a single cell including a fuel electrode, an electrolyte layer, and an air electrode, and has a first gas flow space facing the fuel electrode and a second gas flow space facing the air electrode. An electrochemical reaction cell stack, a generator that generates a first gas supplied to the first gas flow space, a combustor that burns a combustion gas and heats the generator with the combustion heat, and a container that houses the generator and the combustor. The combustor has a jet surface where a jet outlet through which the combustion gas jets is open, and the jet surface does not directly face the generator.

[0008] According to the above configuration, it is possible to avoid the generator being directly heated by the flame or radiant heat formed by the combustor, and the over-temperature rise of the generator is suppressed.

[0009] (2) The electrochemical reaction module described in (1) above may include a separating member that separates the generator and the jet surface.

[0010] According to such a configuration, by the separating member separating the generator and the jet surface, the jet surface can be prevented from directly facing the generator. Thereby, the over-temperature rise of the generator is suppressed with a simple configuration.

[0011] (3) In the electrochemical reaction module described in (2) above, the separating member may be a member that partially partitions the space around the generator and the space around the combustor.

[0012] According to such a configuration, the surrounding air heated by the combustor flows into the vicinity of the generator. Thereby, compared with the case where the separating member completely partitions the vicinity of the generator and the vicinity of the combustor, while suppressing the over-temperature rise of the generator, the first gas generated by the generator can be sufficiently heated to the temperature at which the electrochemical reaction cell stack operates.

[0013] (4) In the electrochemical reaction module according to (3) above, the isolation member may be arranged at intervals with respect to both the combustor and the generator.

[0014] According to such a configuration, it is possible to suppress heat transfer from the combustor to the generator through the isolation member. Further, since the ambient air heated by the combustor flows into the space between the generator and the isolation member, while suppressing an excessive temperature rise of the generator, the first gas generated by the generator can be sufficiently heated to the temperature at which the electrochemical reaction cell stack operates.

[0015] (5) In the electrochemical reaction module according to (2) above, the isolation member may be a supply path constituting member that constitutes a gas supply path through which the second gas supplied to the second gas flow space flows.

[0016] According to such a configuration, while suppressing an excessive temperature rise of the generator, the combustion heat generated by combustion can be efficiently transferred to the second gas supplied to the second gas flow space. Thereby, while suppressing an excessive temperature rise of the generator, the electrochemical reaction cell stack can be efficiently heated to an operable temperature. That is, it is possible to achieve both suppression of an excessive temperature rise of the generator and rapid startup of the electrochemical cell stack in a short time.

[0017] (6) In the electrochemical reaction module according to (2) above, the generator has a facing surface facing the combustor, and the isolation member may be arranged on the facing surface.

[0018] According to such a configuration, the isolation member can be arranged between the generator and the ejection surface without adding another configuration for supporting the isolation member, and complication of the configuration can be avoided.

[0019] (7) In the electrochemical reaction module according to (6) above, the isolation member may be a heat insulating material having heat insulating properties.

[0020] Since the heat insulating material generally also has a heat storage effect, for example, when the temperature drops for some reason during the operation of the cell stack, it is possible to suppress the temperature of the generator from dropping and hindering the generation of the first gas.

[0021] (8) In the electrochemical reaction module according to (1) above, the spraying surface may be a surface different from the surface facing the generator in the combustor.

[0022] According to such a configuration, since the spraying surface is a surface different from the surface facing the generator in the combustor, the spraying surface can be prevented from directly facing the generator. Thereby, the overheating of the generator is suppressed with a simple configuration.

[0023] Note that the technology disclosed in this specification can be realized in various forms. For example, it can be realized in the form of a fuel cell module including a generator and a combustor, and a manufacturing method thereof.

Brief Description of Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Modes for Carrying Out the Invention

[0025] A. Embodiment: A-1. Configuration of Fuel Cell Module 10: The embodiment will be described with reference to FIGS. 1 to 7. The fuel cell module 10 (an example of an electrochemical reaction module) of the present embodiment includes, as shown in FIGS. 1 and 2, a fuel cell stack 100 (an example of an electrochemical reaction cell stack) that generates electricity using an electrochemical reaction between hydrogen and oxygen, and an auxiliary device 400 that supplies a fuel gas FG (an example of a first gas) and an oxidant gas OG (an example of a second gas) to the fuel cell stack 100. The auxiliary device 400 includes a combustor 420, a reformer 430 (an example of a generator), an evaporator 440, a housing 410 (an example of a container) that houses the combustor 420 and the reformer 430 therein, and a heat insulating material 500 (an example of an isolation member) disposed on the outer surface of the reformer 430. The fuel cell module 10 of the present embodiment is used for a solid oxide type fuel cell including an electrolyte layer 112 containing a solid oxide.

[0026] (Fuel Cell Stack 100) As shown in FIGS. 2 and 3, the fuel cell stack 100 includes a power generation block 101, a first terminal plate 240, a second terminal plate 250, two insulating plates 220, a first end plate 210, and a second end plate 270. The first end plate 210, one insulating plate 220, the first terminal plate 240, the power generation block 101, the second terminal plate 250, the other insulating plate 220, and the second end plate 270 have substantially the same-sized rectangular outer shapes and are arranged to overlap in this order in a predetermined arrangement direction (the direction along the Z-axis in FIGS. 2 and 3).

[0027] As shown in FIG. 3, the fuel cell stack 100 has bolt holes BH that penetrate from the first end plate 210 to the second end plate 270 near each of the four corners. Bolts B are inserted into each bolt hole BH. Nuts N are screwed onto both ends of each bolt B. These bolts B and nuts N integrally fasten the members from the first end plate 210 to the second end plate 270.

[0028] The power generation block 101 is composed of a plurality of electrochemical reaction units 101U (hereinafter sometimes abbreviated as "reaction units 101U") arranged side by side in a predetermined arrangement direction (the direction along the Z-axis in FIGS. 4 and 5).

[0029] (Electrochemical reaction unit 101U) As shown in FIGS. 4 and 5, the electrochemical reaction unit 101U includes a single cell 110, a separator 120 for the single cell, an air electrode frame 130, a fuel electrode frame 140, an air electrode current collecting member 134, a fuel electrode current collecting member 144, and two interconnects 150. One interconnect 150, the air electrode frame 130, the separator 120 for the single cell, the fuel electrode frame 140, and the other interconnect 150 have substantially the same-sized rectangular outer shapes and are arranged to overlap in this order. The single cell 110 is supported by the separator 120 for the single cell, the air electrode current collecting member 134 is disposed between the single cell 110 and one interconnect 150, and the fuel electrode current collecting member 144 is disposed between the single cell 110 and the other interconnect 150.

[0030] As shown in FIGS. 4 and 5, the interconnect 150 is shared by two adjacent reaction units 101U. However, the reaction unit 101U located at one end among the plurality of reaction units 101U does not include the interconnect 150 adjacent to the air electrode frame 130, and the first terminal plate 240 overlaps the air electrode frame 130. Further, the reaction unit 101U located at the other end among the plurality of reaction units 101U does not include the interconnect 150 adjacent to the fuel electrode frame 140, and the second terminal plate 250 overlaps the fuel electrode frame 140.

[0031] (Single cell 110) The single cell 110 includes an electrolyte layer 112, an air electrode 114, and a fuel electrode 116. As shown in FIGS. 4 and 5, the air electrode 114, the electrolyte layer 112, and the fuel electrode 116 are arranged to overlap in this order. The single cell 110 of the present embodiment is a fuel electrode support type single cell in which the other layers (electrolyte layer 112, air electrode 114) constituting the single cell 110 are supported by the fuel electrode 116.

[0032] The electrolyte layer 112 is a rectangular flat plate-like member, having one surface (the upper surface in FIG. 4) where the air electrode 114 is disposed, and the other surface (the lower surface in FIG. 4) where the fuel electrode 116 is disposed and is parallel to one surface. The electrolyte layer 112 is a layer containing a solid oxide (for example, YSZ (yttria-stabilized zirconia)). The air electrode 114 is a layer having a rectangular outer shape smaller than that of the electrolyte layer 112, and contains, for example, a perovskite-type oxide (for example, LSCF (lanthanum strontium cobalt ferrite)). The fuel electrode 116 is a layer having a rectangular outer shape substantially the same size as that of the electrolyte layer 112, and contains, for example, Ni (nickel), a cermet composed of Ni and ceramic particles, a Ni-based alloy, or the like.

[0033] (Separator 120 for single cell) As shown in FIGS. 4 and 5, the separator 120 for single cell is a rectangular frame-like member having a substantially rectangular through-hole 121 near the center, and is formed of, for example, a metal. The peripheral portion of the through-hole 121 in the separator 120 for single cell is joined to the peripheral portion of one surface (the surface where the air electrode 114 is disposed: the upper surface in FIG. 4) of the electrolyte layer 112 by a joining portion 124. The joining portion 124 is formed of, for example, a brazing material (Ag brazing material).

[0034] (Air electrode frame 130) As shown in FIGS. 4 and 5, the air electrode frame 130 is a rectangular frame-like member having a substantially rectangular through-hole 131 near the center, and is formed of, for example, an insulating ceramic (such as mica).

[0035] (Fuel electrode frame 140) As shown in FIGS. 4 and 5, the fuel electrode frame 140 is a rectangular frame-like member having a substantially rectangular through-hole 141 near the center, and is formed of, for example, a metal.

[0036] (Interconnector 150) The interconnector 150 is a rectangular plate-like member, and is formed of, for example, a metal.

[0037] (Air electrode current collector member 134 and fuel electrode current collector member 144) The air electrode current collector member 134 is a square columnar member that connects the air electrode 114 and the interconnector 150, and a plurality of them are arranged between the air electrode 114 and the interconnector 150. Each air electrode current collector member 134 is formed of, for example, a ferrite-based stainless steel.

[0038] The fuel electrode current collector member 144 is a member that connects the interconnector 150 and the fuel electrode 116, and is formed of a conductive material such as nickel, a nickel alloy, or stainless steel, for example. The fuel electrode current collector member 144 includes an interconnector facing portion 146, an electrode facing portion 145 parallel to the interconnector facing portion 146, and a connecting portion 147 that connects the electrode facing portion 145 and the interconnector facing portion 146, and has a U shape as a whole. The electrode facing portion 145 is in contact with the fuel electrode 116, and the interconnector facing portion 146 is in contact with the interconnector 150. A spacer 149 formed of, for example, mica is disposed between the electrode facing portion 145 and the interconnector facing portion 146.

[0039] As described above, the interconnector 150 is shared by two adjacent reaction units 101U. More specifically, as shown in FIGS. 4 and 5, one interconnector 150 is electrically connected to the air electrode 114 of the single cell 110 provided in one of the two adjacent reaction units 101U via the air electrode current collector member 134, and is electrically connected to the fuel electrode 116 of the single cell 110 provided in the other of the two adjacent reaction units 101U via the fuel electrode current collector member 144. Thereby, electrical continuity between two adjacent reaction units 101U is ensured.

[0040] However, as described above, among the plurality of reaction units 101U, the reaction unit 101U located at one end does not include the interconnector 150 on the air electrode 114 side. The air electrode 114 provided in this reaction unit 101U is connected to the first terminal plate 240 via the air electrode current collecting member 134. Also, among the plurality of reaction units 101U, the reaction unit 101U located at the other end does not include the interconnector 150 on the fuel electrode 116 side. The fuel electrode 116 provided in this reaction unit 101U is connected to the second terminal plate 250 via the fuel electrode current collecting member 144. The first terminal plate 240 functions as the positive output terminal of the fuel cell stack 100. The second terminal plate 250 functions as the negative output terminal of the fuel cell stack 100.

[0041] (Air chamber 313 and fuel chamber 323) As shown in FIGS. 4 and 5, the space defined by the single-cell separator 120, the single cell 110, the air electrode frame 130, and the interconnector 150 faces the air electrode 114 and serves as an air chamber 313 (an example of a second gas flow space) through which the oxidant gas OG flows. The air electrode frame 130 partitions the air chamber 313 from the external space over the entire circumference, seals the space between the single-cell separator 120 and the interconnector 150, and plays a role in preventing gas from leaking out of the air chamber 313 to the external space.

[0042] Also, the space defined by the single-cell separator 120, the single cell 110, the fuel electrode frame 140, and the interconnector 150 faces the fuel electrode 116 and serves as a fuel chamber 323 (an example of a first gas flow space) through which the fuel gas FG flows. The fuel electrode frame 140 partitions the fuel chamber 323 from the external space over the entire circumference, seals the space between the single-cell separator 120 and the interconnector 150, and plays a role in preventing gas from leaking out of the fuel chamber 323 to the external space.

[0043] The separator 120 for a single cell separates the air chamber 313 and the fuel chamber 323, suppressing the leakage (cross leakage) of gas from the air electrode 114 side to the fuel electrode 116 side or from the fuel electrode 116 side to the air electrode 114 side around the single cell 110. Further, the interconnector 150 suppresses the leakage of gas between adjacent reaction units 101U.

[0044] (Manifolds 311, 312, 321, 322) As shown in FIGS. 3, 4, and 5, the fuel cell stack 100 has four holes penetrating from the power generation block 101 to the second end plate 270. The four holes are the oxidant gas supply manifold 311, the oxidant gas discharge manifold 312, the fuel gas supply manifold 321, and the fuel gas discharge manifold 322, respectively.

[0045] As shown in FIG. 4, the oxidant gas supply manifold 311 is a gas flow path that supplies the oxidant gas OG introduced from outside the fuel cell stack 100 to the air chamber 313 of each reaction unit 101U. The oxidant gas discharge manifold 312 is a gas flow path that discharges the oxidant gas (oxidant off-gas OOG) discharged from the air chamber 313 without being used for power generation to the outside of the fuel cell stack 100. For example, air is used as the oxidant gas OG.

[0046] As shown in FIG. 5, the fuel gas supply manifold 321 is a gas flow path that supplies the fuel gas FG introduced from outside the fuel cell stack 100 to the fuel chamber 323 of each reaction unit 101U. The fuel gas discharge manifold 322 is a gas flow path that discharges the fuel gas (fuel off-gas FOG) discharged from the fuel chamber 323 without being used for power generation to the outside of the fuel cell stack 100.

[0047] (Auxiliary device 400) The auxiliary device 400 is a device for supplying fuel gas FG obtained by reforming raw fuel gas RFG and air as oxidant gas OG to the fuel cell stack 100, and is arranged above the fuel cell stack 100 as shown in FIG. 2. As shown in FIGS. 1 and 2, the auxiliary device 400 includes a housing 410, a combustor 420 and a reformer 430 arranged inside the housing 410, and an evaporator 440 arranged above the housing 410.

[0048] In addition, in FIG. 1, the flow of the gas on the fuel electrode side (raw fuel gas RFG, fuel gas FG, and fuel off-gas FOG) is indicated by a dashed-dotted line, the flow of the gas on the air electrode side (oxidant gas OG and oxidant off-gas OOG) is indicated by a solid line, and the flow of the exhaust gas EG generated by the combustor 420 is indicated by a broken line.

[0049] (Housing 410) As shown in FIG. 1, the housing 410 is a double container including an outer box 411 and an inner box 412 that is slightly smaller than the outer box 411 and is arranged inside the outer box 411. The outer box 411 and the inner box 412 are made of, for example, metal and are sealed box-shaped containers. The reformer 430 and the combustor 420 are accommodated inside the inner box 412. The space between the outer box 411 and the inner box 412 serves as an air flow path 413, and heat transfer fins 414 are arranged inside the air flow path 413.

[0050] An air supply pipe 451 for supplying oxidant gas OG (air) to the inside of the air flow path 413 and an oxidant gas supply pipe 452 that communicates with the oxidant gas supply manifold 311 and supplies the oxidant gas OG that has passed through the inside of the air flow path 413 to the fuel cell stack 100 are connected to the outer box 411. An exhaust gas relay pipe 481 for sending the exhaust gas EG generated by the combustor 420 to the evaporator 440 is connected to the inner box 412.

[0051] (Evaporator 440) The evaporator 440 is a device for evaporating reformed water RW to generate steam, mixing this steam with the raw fuel gas RFG, and supplying it to the reformer 430. The evaporator 440 is connected with a reformed water supply pipe 471 for introducing reformed water RW therein, a raw fuel gas supply pipe 461 for introducing raw fuel gas RFG therein, a mixed gas supply pipe 462 that communicates with the internal space of the reformer 430 and supplies the mixed gas from the evaporator 440 to the reformer 430, and an exhaust gas discharge pipe 482 for discharging the exhaust gas EG outside after it has been used for heating the reformed water RW.

[0052] (Reformer 430) The reformer 430 is a device for reforming the raw fuel gas RFG mixed with steam supplied from the evaporator 440 to generate a hydrogen-rich fuel gas FG. The reformer 430 includes a reforming container 431 and a reforming catalyst 432 filled inside the reforming container 431 to promote the reforming reaction. The outer surface of the reforming container 431 includes an opposing surface 431F facing the combustor 420. A fuel gas supply pipe 463 that communicates with the fuel gas supply manifold 321 and supplies the fuel gas FG to the fuel cell stack 100 is connected to the reformer 430.

[0053] (Combustor 420) The combustor 420 is a device for mixing and burning the fuel off-gas FOG and the oxidant off-gas OOG discharged without being used in the power generation reaction by the fuel cell stack 100 to generate the exhaust gas EG and heating the reformer 430 and the fuel cell stack 100. The combustor 420 is arranged below the reformer 430. The combustor 420 is connected with an oxidant gas discharge pipe 453 that communicates with the oxidant gas discharge manifold 312 and a fuel gas discharge pipe 464 that communicates with the fuel gas discharge manifold 322.

[0054] As shown in FIGS. 6 and 7, the combustor 420 includes a main body portion 421 and a partition member 429. The main body portion 421 is made of metal and is disposed on the bottom surface 412F of the inner box 412. The main body portion 421 includes a first top wall 422, a first peripheral wall 423, a plurality of ejection cylinders 425, a second top wall 426, and a second peripheral wall 427.

[0055] The first top wall 422 is an elongated flat plate-shaped portion and is disposed parallel to the bottom surface 412F. The first peripheral wall 423 is a frame-shaped portion extending downward, that is, toward the bottom surface 412F, from the outer peripheral edge of the first top wall 422. The outer surface (the upper surface in FIGS. 6 and 7) of the first top wall 422 serves as an ejection surface 422F facing the reformer 430. The first top wall 422 is provided with a plurality of first ejection ports 424 (an example of an ejection port) that open to the ejection surface 422F. Each ejection cylinder 425 is a short cylindrical portion extending upward, that is, in a direction opposite to the bottom surface 412F, from the opening edge of each first ejection port 424. The second top wall 426 is a wall extending outward from the lower end of the first peripheral wall 423 and is disposed parallel to the bottom surface 412F. The second peripheral wall 427 is a frame-shaped portion extending downward, that is, toward the bottom surface 412F, from the outer peripheral edge of the second top wall 426. The lower end portion of the second peripheral wall 427 is bent outward and joined to the bottom surface 412F by welding. The second top wall 426 has a plurality of second ejection ports 428.

[0056] The space surrounded by the first top wall 422 and the first peripheral wall 423 is a first guide flow path FP1, and the fuel off-gas FOG supplied from the fuel gas discharge pipe 464 flows through the inside of the first guide flow path FP1. The space surrounded by the second top wall 426, the second peripheral wall 427, and the bottom surface 412F is a second guide flow path FP2, and the oxidant off-gas OOG supplied from the oxidant gas discharge pipe 453 flows through the inside of the second guide flow path FP2. The partition member 429 is a member that separates the first guide flow path FP1 and the second guide flow path FP2.

[0057] (Heat insulating material 500) The heat insulation material 500 is a member for blocking the heat from the combustor 420 and suppressing the heat transfer to the reformer 430, and is disposed on the facing surface 431F of the reformer 430. The heat insulation material 500 is in the shape of a plate with a uniform thickness and has an outer shape substantially equal to that of the facing surface 431F. The heat insulation material 500 is disposed over the entire surface of the facing surface 431F, and the entire facing surface 431F is separated from the ejection surface 422F by the heat insulation material 500. That is, the ejection surface 422F does not directly face the reformer 430. As the material of the heat insulation material 500, a known material having heat insulation properties can be used. The heat insulation material 500 may be attached to the facing surface 431F with an adhesive having heat resistance, for example.

[0058] A-2. Operation of the fuel cell module 10 When the fuel cell module 10 is started up, as shown in FIG. 1, the oxidant gas OG supplied through the air supply pipe 451 is supplied to the air chamber 313 through the air flow path 413, the oxidant gas supply pipe 452, and the oxidant gas supply manifold 311. Further, the raw fuel gas RFG (for example, city gas) is supplied to the evaporator 440 through the raw fuel gas supply pipe 461, and the reforming water RW is supplied through the reforming water supply pipe 471. The raw fuel gas RFG passes through the evaporator 440 and is supplied to the reformer 430. In the initial stage of starting up the fuel cell module 10, since the temperature of the reformer 430 is low, the reaction for reforming the raw fuel gas RFG does not occur. The raw fuel gas RFG that has passed through the reformer 430 is supplied to the fuel chamber 323 through the fuel gas supply pipe 463 and the fuel gas supply manifold 321.

[0059] In the initial stage of starting up the fuel cell module 10, the power generation reaction does not occur in the single cell 110, and the oxidant gas OG supplied to the air chamber 313 is directly supplied to the combustor 420 through the oxidant gas discharge manifold 312 and the oxidant gas discharge pipe 453. Further, the raw fuel gas RFG supplied to the fuel chamber 323 is directly supplied to the combustor 420 through the fuel gas discharge manifold 322 and the fuel gas discharge pipe 464.

[0060] The oxidant gas OG supplied to the combustor 420 flows inside the second guide flow path FP2 and is ejected from the second ejection port 428 toward the internal space of the inner box 412. The raw fuel gas RFG (an example of a combustion gas) supplied to the combustor 420 flows inside the first guide flow path FP1 and is ejected from the first ejection port 424 toward the internal space of the inner box 412. The ejected raw fuel gas RFG is ignited by an ignition device (not shown) and burns together with the oxidant gas OG. The combustion heat generated by this combustion heats the reformer 430 and the oxidant gas OG flowing through the air flow path 413. Further, the high-temperature exhaust gas EG generated by combustion is supplied to the evaporator 440 through the exhaust gas relay pipe 481 and is used to heat the reforming water RW to generate steam.

[0061] When steam is generated in the evaporator 440, this steam is mixed with the raw fuel gas RFG. The mixed gas of steam and the raw fuel gas RFG is supplied to the reformer 430 through the mixed gas supply pipe 462. When the temperature of the reformer 430 rises sufficiently due to the combustion heat generated from the combustor 420, the raw fuel gas RFG comes into contact with the reforming catalyst 432 inside the reformer 430, causing a steam reforming reaction and generating a hydrogen-rich fuel gas FG. The generated fuel gas FG is supplied to the fuel chamber 323 through the fuel gas supply pipe 463 and the fuel gas supply manifold 321.

[0062] Also, while flowing inside the air flow path 413, the oxidant gas OG is heated by the combustion heat generated from the combustor 420 and is supplied to the air chamber 313 through the oxidant gas supply pipe 452 and the oxidant gas supply manifold 311. The supply of the high-temperature oxidant gas OG inside heats the fuel cell stack 100.

[0063] When the temperature of the fuel cell stack 100 rises sufficiently, power generation by the electrochemical reaction of the oxidant gas OG and the fuel gas FG occurs in the single cell 110. This power generation reaction is an exothermic reaction. As described above, the interconnector 150 is shared by two adjacent reaction units 101U, and electrical continuity between the two adjacent reaction units 101U is ensured by the interconnector 150. That is, the plurality of reaction units 101U included in the fuel cell stack 100 are electrically connected in series. Further, the first terminal plate 240 is electrically connected to the reaction unit 101U located at one end among the plurality of reaction units 101U, and the second terminal plate 250 is electrically connected to the reaction unit 101U located at the other end. Thereby, the electrical energy generated in each reaction unit 101U is taken out from the second terminal plate 250 that functions as an output terminal of the fuel cell stack 100. Since the SOFC generates power at a relatively high temperature (for example, 700°C to 1000°C), after startup, the fuel cell stack 100 may be heated by a heater (not shown) until it reaches a state where the high temperature can be maintained by the heat generated by power generation.

[0064] The oxidant off-gas OOG discharged from the air chamber 313 to the oxidant gas discharge manifold 312 is supplied to the combustor 420 through the oxidant gas discharge pipe 453. Further, the fuel off-gas FOG (an example of a combustion gas) discharged from the fuel chamber 323 to the fuel gas discharge manifold 322 is supplied to the combustor 420 through the fuel gas discharge pipe 464.

[0065] The oxidant off-gas OOG supplied to the combustor 420 flows inside the second guide flow path FP2 and is ejected from the second ejection port 428 toward the internal space of the inner box 412. The fuel off-gas FOG supplied to the combustor 420 flows inside the first guide flow path FP1 and is ejected from the first ejection port 424 toward the internal space of the inner box 412. The ejected fuel off-gas FOG burns together with the oxidant off-gas OOG. The combustion heat generated by this combustion heats the reformer 430 and the oxidant gas OG flowing through the air flow path 413. Further, the high-temperature exhaust gas EG generated by the combustion is supplied to the evaporator 440 through the exhaust gas relay pipe 481 and is used to heat the reforming water RW to generate steam.

[0066] Here, if the firepower of the combustor 420 is increased in order to sufficiently heat the fuel gas FG and the oxidant gas OG, there is a concern that due to heat, the members constituting the reformer 430 may be deformed or damaged, or the reforming catalyst 432 may deteriorate, resulting in a decrease in reforming efficiency. In particular, at the initial stage of startup of the fuel cell module 10, in order to heat the fuel cell stack 100 to a power generation-capable temperature in a short time, it is necessary to sufficiently heat the oxidant gas OG and supply it to the fuel cell stack 100. For this reason, it is necessary to increase the firepower of the combustor 420 to a certain extent, and the above problems become prominent.

[0067] In the present embodiment, the heat insulating material 500 is disposed on the facing surface 431F of the reformer 430, and the ejection surface 422F of the combustor 420 is separated from the reformer 430 by the heat insulating material 500. That is, the ejection surface 422F does not directly face the reformer 430. According to such a configuration, the heat insulating material 500 separates the reformer 430 from the flame formed by the combustor 420, and suppresses the radiant heat from the combustor 420 from directly being transmitted to the reformer 430. Thereby, the over-temperature rise of the reformer 430 is suppressed, and the deformation or damage of the members constituting the reformer 430 and the deterioration of the reforming catalyst 432 are suppressed.

[0068] A-3. Effects of the present embodiment: As described above, the fuel cell module 10 of the present embodiment includes a single cell 110 including a fuel electrode 116, an electrolyte layer 112, and an air electrode 114, a fuel cell stack 100 having a fuel chamber 323 facing the fuel electrode 116 and an air chamber 313 facing the air electrode 114, a reformer 430 that generates a fuel gas FG supplied to the fuel chamber 323, a combustor 420 that burns a fuel off-gas FOG and heats the reformer 430 with the combustion heat thereof, and a housing 410 that houses the reformer 430 and the combustor 420. The combustor 420 has a jet surface 422F at which a first jet outlet 424 from which the fuel off-gas FOG (raw fuel gas RFG at the initial stage of startup of the fuel cell module 10) jets is opened, and the jet surface 422F does not directly face the reformer 430.

[0069] According to the above configuration, it is possible to avoid the reformer 430 being directly heated by the flame and radiant heat formed by the combustor 420, and to suppress an excessive temperature rise of the reformer 430.

[0070] Further, the fuel cell module 10 includes a heat insulating material 500 that separates the reformer 430 and the jet surface 422F. According to such a configuration, by the heat insulating material 500 separating the reformer 430 and the jet surface 422F, it is possible to prevent the jet surface 422F from directly facing the reformer 430. Thereby, an excessive temperature rise of the reformer 430 is suppressed with a simple configuration. Further, since the heat insulating material 500 generally also has a heat storage effect, for example, when heating becomes temporarily insufficient for some reason during the operation of the fuel cell stack 100, it is possible to suppress the temperature of the reformer 430 from decreasing and hindering the generation of the fuel gas FG.

[0071] Further, the reformer 430 has a facing surface 431F facing the combustor 420, and the heat insulating material 500 is disposed on the facing surface 431F. According to such a configuration, the heat insulating material 500 can be disposed between the reformer 430 and the jet surface 422F without adding another configuration for supporting the heat insulating material 500, and complication of the configuration can be avoided.

[0072] B. Second Embodiment The second embodiment will be described with reference to FIGS. 8 and 9. The fuel cell module 10B of this embodiment is different from the first embodiment in that the reformer 430 and the combustor 420 are separated by a partition wall 600.

[0073] The partition wall 600 is made of, for example, metal and is disposed inside the inner box 412 between the reformer 430 and the combustor 420. The partition wall 600 is spaced apart from both the reformer 430 and the combustor 420. The outer peripheral edge of the partition wall 600 is joined to the inner surface of the inner box 412 over the entire circumference, for example, by welding.

[0074] The partition wall 600 has a plurality (two in this embodiment) of slits S1, S2. The two slits S1, S2 are elongated holes that penetrate the partition wall 600, respectively. That is, the partition wall 600 partially partitions the space around the reformer 430 and the space around the combustor 420.

[0075] The slits S1, S2 are arranged in the partition wall 600 so as to avoid the region where the opposing surface 431F faces, and also so as to avoid the region where the ejection surface 422F faces. As a result, the entire opposing surface 431F is separated from the combustor 420, and the entire ejection surface 422F is separated from the reformer 430.

[0076] The slit S1 is arranged near the inlet of the raw fuel gas RFG to the reformer 430, that is, near the connection position of the mixed gas supply pipe 462 to the reformer 430. The slit S2 is arranged near the outlet of the fuel gas FG from the reformer 430, that is, near the connection position of the fuel gas supply pipe 463 to the reformer 430. The opening area of the slit S1 is larger than the opening area of the slit S2.

[0077] Since the other configurations are the same as those of the first embodiment, the same reference numerals are given to the same configurations as those of the first embodiment, and the description thereof is omitted.

[0078] As described above, in this embodiment, the reformer 430 and the ejection surface 422F are separated by the partition wall 600, and the ejection surface 422F does not face the reformer 430 directly. Thereby, it is possible to avoid the reformer 430 being directly heated by the flame and radiant heat formed by the combustor 420, and the over-temperature rise of the reformer 430 is suppressed.

[0079] In addition, the partition wall 600 partially partitions the space around the reformer 430 and the space around the combustor 420. According to such a configuration, the surrounding air heated by the combustor 420 flows into the space around the reformer 430 through the slits S1 and S2. Thereby, compared with the case where the space around the reformer 430 and the space around the combustor 420 are completely partitioned by the partition wall 600, while suppressing the over-temperature rise of the reformer 430, the fuel gas FG generated by the reformer 430 can be sufficiently heated to the temperature at which the fuel cell stack 100 operates.

[0080] Also, the partition wall 600 is arranged at an interval with respect to both the combustor 420 and the reformer 430. According to such a configuration, heat transfer from the combustor 420 to the reformer 430 via the partition wall 600 can be suppressed. In addition, the surrounding air heated by the combustor 420 flows between the reformer 430 and the partition wall 600, whereby the reformer 430 is indirectly heated. Thereby, while suppressing the over-temperature rise of the reformer 430, the fuel gas FG generated by the reformer 430 can be sufficiently heated to the temperature at which the fuel cell stack 100 operates.

[0081] In addition, the raw fuel gas RFG supplied to the reformer 430 is reformed into the fuel gas FG inside the reformer 430, and while passing through the reformer 430 while warming the inside thereof, it is discharged to the fuel gas supply pipe 463. That is, in the reformer 430, the vicinity of the connection position with the mixed gas supply pipe 462 is likely to be at a lower temperature compared to the vicinity of the connection position with the fuel gas supply pipe 463. By making the opening area of the slit S1 arranged near the relatively low-temperature region larger than the opening area of the slit S2 arranged near the relatively high-temperature region, the surrounding air heated by the combustor 420 can flow more into the vicinity of the relatively low-temperature region, and the entire reformer 430 can be heated evenly.

[0082] C. Third Embodiment The third embodiment will be described with reference to FIG. 10. The fuel cell module 10C of the present embodiment is different from the first embodiment in that the reformer 430 and the combustor 420 are separated by the first housing 710.

[0083] The fuel cell module 10C includes a first housing 710 (an example of a container) that houses the combustor 420, and a second housing 720 (an example of a container) that houses the reformer 430.

[0084] The first housing 710 is a double container including an outer box 711 (an example of an isolation member and a supply path forming member) and an inner box 712 (an example of an isolation member and a supply path forming member) that is slightly smaller than the outer box 711 and is arranged inside the outer box 711. The outer box 711 and the inner box 712 are made of, for example, metal and are sealed box-shaped containers. The combustor 420 is housed inside the inner box 712. The space between the outer box 711 and the inner box 712 serves as an air flow path 713 (an example of a gas supply path). Inside the air flow path 713, heat transfer fins 414 are arranged in the same manner as in the first embodiment. The outer box 711 and the inner box 712 are arranged so as to surround the entire combustor 420, and a part of them (the part arranged above the combustor 420 in FIG. 10) is arranged to face the ejection surface 422F.

[0085] In the outer case 711, an air supply pipe 451 for supplying oxidant gas OG (air) to the inside of the air flow path 713 and an oxidant gas supply pipe 452 that communicates with the oxidant gas supply manifold 311 and supplies the oxidant gas OG that has passed through the inside of the air flow path 713 to the fuel cell stack 100 are connected. To the inner case 712, a first exhaust gas relay pipe 731 for sending out the exhaust gas EG generated by the combustor 420 to the second housing 720 is connected. Similar to the first embodiment, during the operation of the fuel cell module 10, the oxidant gas OG supplied through the air supply pipe 451 is supplied to the air chamber 313 through the inside of the air flow path 713, the oxidant gas supply pipe 452, and the oxidant gas supply manifold 311.

[0086] The second housing 720 is, for example, made of metal and is a sealed box-shaped container. The second housing 720 is arranged to overlap the upper surface of the outer case 711, and the reformer 430 is housed inside. The reformer 430 is heated by the high-temperature exhaust gas EG supplied to the inside of the second housing 720. To the second housing 720, a second exhaust gas relay pipe 732 for sending out the exhaust gas EG to the evaporator 440 is connected.

[0087] Since other configurations are the same as those in the first embodiment, the same reference numerals are given to the same configurations as those in the first embodiment, and the description thereof is omitted.

[0088] As described above, in the present embodiment, the outer case 711 and the inner case 712 that constitute the air flow path 713 through which the oxidant gas OG supplied to the air chamber 313 flows also serve as a separating member that separates the jet surface 422F of the combustor 420 and the reformer 430.

[0089] According to such a configuration, since the spraying surface 422F does not directly face the reformer 430, it is possible to avoid the reformer 430 being directly heated by the flame and radiant heat formed by the combustor 420. On the other hand, among the inner boxes 712 constituting the air flow path 713, the heat of combustion is efficiently transmitted to the portion facing the spraying surface 422F. Thereby, while suppressing the over-temperature rise of the reformer 430, the heat of combustion can be efficiently transmitted to the oxidant gas OG supplied to the air flow path 713, and the fuel cell stack 100 can be efficiently heated to an operable temperature. That is, it is possible to achieve both suppression of the over-temperature rise of the reformer 430 and the start-up (rapid start-up) of the fuel cell stack 100 in a short time.

[0090] D. Fourth Embodiment The fourth embodiment will be described with reference to FIG. 11. In the fuel cell module 10D of this embodiment, the position of the spraying surface 810 in the combustor 420D is different from that in the first embodiment.

[0091] The combustor 420D of this embodiment has a spraying surface 810. In this spraying surface 810, similar to the first embodiment, a first spray outlet 811 through which the fuel off-gas FOG (raw fuel gas RFG at the initial stage of starting the fuel cell module 10) is ejected is opened. The spraying surface 810 is arranged on a surface (side surface in FIG. 11) different from the surface facing the reformer 430 (upper surface in FIG. 11) in the combustor 420D, so that the spraying surface 810 does not directly face the reformer 430. Thereby, it is possible to avoid the reformer 430 being directly heated by the flame formed by the combustor 420D, and the over-temperature rise of the reformer 430 is suppressed.

[0092] E. Modification (1) In the first embodiment, the heat insulating material 500 is arranged over the entire surface of the facing surface 431F. However, the heat insulating material does not necessarily have to be arranged over the entire surface of the facing surface, and it is sufficient if it is arranged in a range facing the spraying surface on the facing surface. (2) In the first embodiment, the insulation 500 had a uniform thickness, but the insulation may have different thicknesses in different locations; for example, the thickness of the insulation near the gas inlet to the generator may be smaller than the thickness of the insulation near the gas outlet from the generator. (3) In the second embodiment, the separating wall 600 has the slits S1 and S2, but the separating member may have one or three or more slits. Alternatively, the separating member may not have a slit. (4) In the second embodiment, the opening area of the slit S1 is larger than the opening area of the slit S2. However, the opening areas of the slits may be arbitrary. For example, all the slits may have the same opening area. (5) In the second embodiment, the outer peripheral edge of the isolation wall 600 was joined to the inner surface of the inner box 412 around its entire circumference, but it is also acceptable for only a portion of the outer peripheral edge of the isolation member to be fixed to the container, with a gap being present between the other portion of the outer peripheral edge of the isolation member and the container. (6) In the third embodiment, the fuel cell module 10C includes a first housing 710 that houses the combustor 420 and a second housing 720 that houses the reformer 430. However, for example, the fuel cell module may include a first housing that houses the combustor and a second housing that houses the first housing and the generator. (7) In the above embodiment, the combustor 420 is disposed below the reformer 430. However, the positional relationship between the combustor and the generator is arbitrary. For example, the generator may be disposed below the combustor, or the generator and the combustor may be disposed side-by-side. (8) In the above embodiment, the evaporator is disposed separately from the reformer. However, the generator may be a device in which the evaporator and the reformer are integrated together. (9) The above configuration is applicable to a module including an electrochemical reaction cell stack, such as a cell stack used in other types of fuel cells, such as a polymer electrolyte fuel cell (PEFC), a phosphoric acid fuel cell (PAFC), and a molten carbonate fuel cell (MCFC), or an electrolysis cell stack including an electrolysis cell unit, which is a constituent unit of a solid oxide electrolysis cell (SOEC), as a single cell. For example, in the case of a module including an SOEC as an electrochemical reaction cell stack, an evaporator and water vapor generated by the evaporator correspond to a generator and a first gas, respectively, and a combustion gas is supplied from the outside to a combustor.

Description of Signs

[0093] 10, 10B, 10C, 10D: Fuel cell module (electrochemical reaction module) 100: Fuel cell stack (electrochemical reaction cell stack) 101: Power generation block 101U: Electrochemical reaction unit 110: Single cell 112: Electrolyte layer 114: Air electrode 116: Fuel electrode 120: Separator for single cell 121: Through hole 124: Junction 130: Air electrode frame 131: Through hole 134: Air electrode current collecting member 140: Fuel electrode frame 141: Through hole 144: Fuel electrode current collecting member 145: Electrode facing portion 146: Interconnector facing portion 147: Connecting portion 149: Spacer 150: Interconnector 210: First end plate 220: Insulating plate 240: First terminal plate 250: Second terminal plate 270: Second end plate 311: Oxidant gas supply manifold 312: Oxidant gas discharge manifold 313: Air chamber (second gas flow space) 321: Fuel gas supply manifold 322: Fuel gas discharge manifold 323: Fuel chamber (first gas flow space) 400: Auxiliary device 410: Housing (container) 411: Outer box 412: Inner box 412BW: Bottom wall 413: Air flow path 414: Heat transfer fin 420, 420D: Combustor 421: Main body portion 422: First top wall 422F, 810: Spray surface 423: First peripheral wall 424, 811: First nozzle (nozzle) 425: Spray cylinder 426: Second top wall 427: Second peripheral wall 428: Second nozzle 429: Partition member 430: Reformer (generator) 431: Reforming container 431F: Opposing surface 432: Reforming catalyst 440: Evaporator 451: Air supply pipe 452: Oxidant gas supply pipe 453: Oxidant gas discharge pipe 461: Raw fuel gas supply pipe 462: Mixed gas supply pipe 463: Fuel gas supply pipe 464: Fuel gas discharge pipe 471: Reforming water supply pipe 481: Exhaust gas relay pipe 482: Exhaust gas discharge pipe 500: Heat insulating material (isolation member) 600: Partition wall (isolation member) 710: First housing (container) 711: Outer box (isolation member, supply path component) 712: Inner box (isolation member, supply path component) 713: Air flow path (gas supply path) 720: Second housing (container) B: Bolt BH: Bolt hole EG: Exhaust gas FG: Fuel gas (first gas) FOG: Fuel off-gas (combustion gas) FP1: First guide flow pathFP2: Second guide channel N: Nut OG: Oxidizing agent gas (second gas) OOG: Oxidizing agent off-gas RFG: Raw fuel gas (combustion gas) RW: Reformed water S1, S2: Slit

Claims

1. An electrochemical reaction module comprising a single cell including a fuel electrode, an electrolyte layer, and an air electrode, and having a first gas flow space facing the fuel electrode and a second gas flow space facing the air electrode; a generator for generating a first gas supplied to the first gas flow space; a combustor for burning a combustion gas and heating the generator with the heat of combustion; a container for housing the generator and the combustor; characterized by comprising: the combustor having a jet surface with an outlet through which the combustion gas jets; the jet surface not directly facing the generator; the electrochemical reaction module.

2. The electrochemical reaction module according to claim 1, further comprising a separating member separating the generator and the jet surface. The electrochemical reaction module according to claim 1.

3. The electrochemical reaction module according to claim 2, wherein the separating member is a member that partially partitions the space around the generator and the space around the combustor. The electrochemical reaction module according to claim 2.

4. The electrochemical reaction module according to claim 3, wherein the separating member is arranged at a distance from both the combustor and the generator. The electrochemical reaction module according to claim 3.

5. The electrochemical reaction module according to claim 2, wherein the separating member is a supply path forming member that forms a gas supply path through which a second gas supplied to the second gas flow space flows. The electrochemical reaction module according to claim 2.

6. The generator has a facing surface facing the combustor; the separating member is arranged on the facing surface. The electrochemical reaction module according to claim 2.

7. The electrochemical reaction module according to claim 6, wherein the separating member is a heat insulating material having heat insulating properties. The electrochemical reaction module according to claim 6.

8. The electrochemical reaction module according to claim 1, wherein the jet surface is a surface different from the surface of the combustor facing the generator. The electrochemical reaction module according to claim 1.

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