JP2022090193A - Fuel cell module - Google Patents

Abstract

To suppress the performance degradation of a single cell and the occurrence of breakage due to the worsening of gas distributivity attributable to a pressure difference between an air electrode side gas passage and a fuel electrode side passage.SOLUTION: A fuel cell module comprises a fuel cell stack provided with a plurality of power generation units, each having a single cell that includes an electrolyte layer, an air electrode and a fuel electrode. The fuel cell module also comprises a combustor for burning a gas, a fuel electrode side gas exhaust passage for connecting between the fuel electrode side gas exhaust manifold of the fuel cell stack and the combustor, and an air electrode side gas exhaust passage for connecting between the air electrode side gas exhaust manifold of the fuel cell stack and the combustor. In a specific gas exhaust passage which is the fuel electrode side gas exhaust passage and/or the air electrode side gas exhaust passage are provided a cooling mechanism for cooing the gas in the specific gas exhaust passage and a pressure control mechanism for adjusting the pressure of a gas in the specific gas exhaust passage and installed downstream of the cooling mechanism.SELECTED DRAWING: Figure 1

Description

The techniques disclosed herein relate to fuel cell modules.

A solid oxide fuel cell (hereinafter referred to as "SOFC") is known as one of the types of fuel cells that generate power by utilizing an electrochemical reaction between hydrogen and oxygen. SOFCs are used, for example, in the form of fuel cell modules comprising a fuel cell stack and a combustor.

The fuel cell stack is a structure having a plurality of power generation units. Each power generation unit has a fuel cell single cell (hereinafter, simply referred to as "single cell") including an electrolyte layer and an air electrode and a fuel electrode facing each other with the electrolyte layer interposed therebetween. Further, the fuel cell stack has a fuel electrode side gas supply manifold that supplies gas (fuel gas) to the fuel chamber facing the fuel electrode in each power generation unit, and gas (fuel off gas) is discharged from the fuel chamber in each power generation unit. Gas discharge manifold on the fuel electrode side, gas supply manifold on the air electrode side that supplies gas (oxidizer gas) to the air chamber facing the air electrode in each power generation unit, and gas (oxidizer off gas) from the air chamber in each power generation unit. ) Is formed on the air electrode side gas discharge manifold.

The combustor is connected to the fuel pole side gas discharge manifold of the fuel cell stack via the fuel pole side gas discharge flow path, and is connected to the fuel pole side gas discharge flow path of the fuel cell stack, and is connected to the air electrode of the fuel cell stack via the air pole side gas discharge flow path. It is connected to the side gas discharge manifold. The gas discharged from the fuel cell stack via each manifold (fuel off gas and oxidant off gas) is introduced into the combustor, mixed and burned in the combustor (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2019-91683

When operating the fuel cell module, for example, the flow rate of gas supplied to the gas electrode side gas supply manifold or the flow rate of gas supplied to the fuel electrode side gas supply manifold for temperature control inside the fuel cell stack. Is increased or decreased. When the difference between the pressure of the gas flow path on the air electrode side and the pressure of the gas flow path on the fuel electrode side becomes large in each power generation unit of the fuel cell stack as the gas flow rate increases or decreases, the gas on the air electrode side in each power generation unit becomes large. The members constituting the flow path or the fuel pole side gas flow path are deformed, the pressure loss of the air pole side gas flow path or the fuel pole side gas flow path becomes large, the gas distribution property deteriorates, and the performance of the single cell deteriorates or deteriorates. , May cause damage. It should be noted that such a problem is common not only to SOFC but also to fuel cell modules of other types of fuel cells.

This specification discloses a technique capable of solving the above-mentioned problems.

The techniques disclosed herein can be realized, for example, in the following forms.

(1) The fuel cell module disclosed herein includes a fuel cell stack. The fuel cell stack comprises a plurality of power generation units each having a single cell including an electrolyte layer and air poles and fuel poles facing each other across the electrolyte layer. The fuel cell stack has a fuel electrode side gas supply manifold that supplies gas to the fuel chamber facing the fuel electrode in each power generation unit, and fuel electrode side gas discharge that discharges gas from the fuel chamber in each power generation unit. The manifold, the air electrode side gas supply manifold that supplies gas to the air chamber facing the air electrode in each power generation unit, and the air electrode side gas discharge manifold that discharges gas from the air chamber in each power generation unit. It has been formed. Further, the fuel cell module includes a combustor for burning gas, a fuel pole side gas discharge flow path connecting the fuel pole side gas discharge manifold and the combustor of the fuel cell stack, and the fuel cell stack. An air pole side gas discharge flow path for connecting the air pole side gas discharge manifold and the combustor is provided. A cooling mechanism for cooling the gas in the specific gas discharge flow path and the cooling mechanism in the specific gas discharge flow path which is at least one of the fuel pole side gas discharge flow path and the air pole side gas discharge flow path. A pressure control mechanism, which is arranged on the downstream side and adjusts the pressure of the gas in the specific gas discharge flow path, is provided.

As described above, in this fuel cell module, cooling for cooling the gas in the specific gas discharge flow path in the specific gas discharge flow path which is at least one of the fuel pole side gas discharge flow path and the air pole side gas discharge flow path. Since a mechanism is provided, it is a general-purpose pressure control mechanism that does not have special heat resistance as a pressure control mechanism for adjusting the pressure of gas in the specific gas discharge flow path on the downstream side of the cooling mechanism in the specific gas discharge flow path. Pressure control mechanism can be provided. Further, in this fuel cell module, the pressure of the gas in the specific gas discharge flow path is adjusted by the pressure control mechanism, so that the pressure of the gas flow path on the air electrode side and the pressure of the gas flow path on the fuel electrode side in each power generation unit can be adjusted. It is possible to prevent the difference between the two from becoming excessive. Therefore, according to this fuel cell module, the air electrode side gas flow path or the fuel electrode side gas flow path in each power generation unit is configured due to the pressure difference between the air electrode side gas flow path and the fuel electrode side gas flow path. It is possible to prevent the pressure loss of the gas flow path on the air electrode side or the gas flow path on the fuel electrode side in each power generation unit from being deformed and the gas distribution property from deteriorating, which in turn causes the gas distribution property to deteriorate. It is possible to suppress the accompanying deterioration, deterioration, and damage of the single cell.

(2) In the fuel cell module, the fuel electrode side gas supply flow path connected to the fuel electrode side gas supply manifold of the fuel cell stack and the air electrode side gas supply manifold of the fuel cell stack are further connected. The air pole side gas supply flow path, at least the air pole side gas supply flow path, the air pole side gas supply manifold, the air chamber of each power generation unit, the air pole side gas discharge manifold, and the air pole side. An air pole side gas flow path including a gas discharge flow path, at least the fuel pole side gas supply flow path, the fuel pole side gas supply manifold, the fuel chamber of each power generation unit, and the fuel pole side gas discharge manifold. The pressure control mechanism is controlled based on the pressure measurement unit for measuring the pressure of at least one of the fuel electrode side gas flow path including the fuel electrode side gas discharge flow path and the pressure measurement result by the pressure measurement unit. It may be configured to include a control unit. According to this fuel cell module, the pressure control mechanism is used to effectively suppress an excessive difference between the pressure of the gas flow path on the air electrode side and the pressure of the gas flow path on the fuel electrode side in each power generation unit. It is possible to effectively suppress the deterioration, deterioration, and damage of the single cell due to the deterioration of gas distributability.

(3) In the fuel cell module, the cooling mechanism and the pressure control mechanism are provided at least in the fuel electrode side gas discharge flow path, and the fuel cell module is a desulfurizer that further desalphates the raw fuel gas. And a branch flow path connecting the position downstream of the cooling mechanism in the fuel electrode side gas discharge flow path and the desulfurization device may be provided. According to this fuel cell module, the gas discharged from the fuel cell stack can be used for desulfurization of the raw fuel gas, and the system efficiency can be improved.

(4) In the fuel cell module, the cooling mechanism specifies at least one of a gas for supplying to the air electrode side gas supply manifold and a gas for supplying to the fuel electrode side gas supply manifold. The configuration may include a heat exchange unit that exchanges heat with the gas in the gas discharge flow path. In this fuel cell module, at least one of the gas to be supplied to the gas electrode side gas supply manifold and the gas to be supplied to the fuel electrode side gas supply manifold in the heat exchange section is the gas in the specific gas discharge flow path. By taking away the heat of the gas, the gas in the specific gas discharge flow path is cooled. Therefore, according to this fuel cell module, it is possible to suppress the decrease in thermal efficiency of the fuel cell module as a whole due to the provision of the cooling mechanism while realizing the cooling of the gas in the specific gas discharge flow path by the cooling mechanism. can.

(5) The fuel cell module further includes an evaporator for evaporating water and a reformer for reforming raw fuel gas using the water evaporated in the evaporator, and the cooling mechanism is provided. The configuration may include a heat exchange unit that exchanges heat between the water supplied to the evaporator and the gas in the specific gas discharge flow path. In this fuel cell module, in the heat exchange section, the water supplied to the evaporator takes heat of the gas in the specific gas discharge flow path, so that the gas in the specific gas discharge flow path is cooled. Therefore, according to this fuel cell module, it is possible to suppress the decrease in thermal efficiency of the fuel cell module as a whole due to the provision of the cooling mechanism while realizing the cooling of the gas in the specific gas discharge flow path by the cooling mechanism. can.

(6) In the fuel cell module, each of the power generation units is further formed with a through hole, and a portion surrounding the through hole is joined to the peripheral edge of the single cell, and the air chamber facing the air electrode and the said. It may be configured to have a first separator that separates the fuel chamber facing the fuel electrode. In this fuel cell module, a configuration is adopted in which the gas distribution property is likely to deteriorate due to the deformation of the first separator bonded to the single cell, but the air electrode side in each power generation unit is used by using the pressure control mechanism. Since it is possible to suppress an excessive difference between the pressure of the gas flow path and the pressure of the gas flow path on the fuel electrode side, it is possible to suppress the deformation of the first separator due to the pressure difference, and the gas distributability deteriorates. It is possible to suppress the deterioration, deterioration, and damage of a single cell due to the above.

(7) In the fuel cell module, each power generation unit is further formed with a conductive interconnector electrically connected to the single cell and a through hole, and a portion surrounding the through hole is the interconnector. As a configuration having a second separator joined to the peripheral portion of the air chamber and partitioning one of the air chamber and the fuel chamber and the other of the air chamber and the fuel chamber in the other power generation unit. May be good. In this fuel cell module, a configuration is adopted in which the gas distribution property is likely to deteriorate due to the deformation of the second separator bonded to the interconnector, but the air electrode side in each power generation unit is used by using the pressure control mechanism. Since it is possible to suppress an excessive difference between the pressure of the gas flow path and the pressure of the gas flow path on the fuel electrode side, it is possible to suppress the deformation of the second separator due to the pressure difference, and the gas distributability deteriorates. It is possible to suppress the deterioration, deterioration, and damage of a single cell due to the above.

The techniques disclosed in the present specification can be realized in various forms, for example, in the form of a fuel cell module and a method for manufacturing the same.

Explanatory drawing which shows typically the structure of the fuel cell module 10 in 1st Embodiment A perspective view showing an external configuration of the fuel cell stack 100 according to the first embodiment. Explanatory drawing which shows the XZ cross-sectional structure of the fuel cell stack 100 at the position of III-III of FIG. Explanatory drawing which shows the YZ cross-sectional structure of the fuel cell stack 100 at the position of IV-IV of FIG. Explanatory drawing which shows the XZ cross section configuration of two power generation units 102 adjacent to each other at the same position as the cross section shown in FIG. Explanatory drawing which shows the YZ cross section configuration of two power generation units 102 adjacent to each other at the same position as the cross section shown in FIG. Explanatory drawing which shows typically the structure of the fuel cell module 10a in 2nd Embodiment Explanatory drawing which shows typically the structure of the fuel cell module 10b in 3rd Embodiment Explanatory drawing which shows typically the structure of the fuel cell module 10c in 4th Embodiment

A. Embodiment:
A-1. Configuration of fuel cell module 10:
FIG. 1 is an explanatory diagram schematically showing the configuration of the fuel cell module 10 in the first embodiment. The fuel cell module 10 includes a fuel cell stack 100 and other devices. Hereinafter, the configuration of the fuel cell stack 100 will be described first, and then the configurations of other devices constituting the fuel cell module 10 will be described.

A-2. Configuration of fuel cell stack 100:
FIG. 2 is a perspective view showing an external configuration of the fuel cell stack 100 according to the first embodiment, and FIG. 3 is an explanatory view showing an XZ cross-sectional configuration of the fuel cell stack 100 at the positions III to III of FIG. FIG. 4 is an explanatory diagram showing a YZ cross-sectional configuration of the fuel cell stack 100 at the position IV-IV of FIG. Each figure shows XYZ axes that are orthogonal to each other to identify the direction. In the present specification, for convenience, the Z-axis positive direction is referred to as an upward direction, and the Z-axis negative direction is referred to as a downward direction, but the fuel cell stack 100 is actually in a direction different from such an orientation. It may be installed.

The fuel cell stack 100 includes a plurality of power generation units 102 and a pair of end plates 104 and 106. The plurality of power generation units 102 are arranged side by side in a predetermined arrangement direction (vertical direction in this embodiment). The pair of end plates 104 and 106 are arranged so as to sandwich an aggregate composed of a plurality of power generation units 102 from above and below.

A plurality of holes penetrating in the vertical direction are formed on the peripheral edge of each layer (power generation unit 102, end plates 104, 106) constituting the fuel cell stack 100, and the holes formed in each layer and corresponding to each other are vertically and vertically formed. Communicating in the direction constitutes a communication hole 108 extending in the vertical direction from one end plate 104 to the other end plate 106. In the following description, the holes formed in each layer of the fuel cell stack 100 to form the communication holes 108 may also be referred to as communication holes 108.

A bolt 22 extending in the vertical direction is inserted into each communication hole 108, and the fuel cell stack 100 is fastened by the bolt 22 and the nuts 24 fitted on both sides of the bolt 22. As shown in FIGS. 3 and 4, an insulating sheet 26 is interposed between the nut 24 and the end plates 104 and 106 (or the gas passage member 27 described later).

A space is secured between the outer peripheral surface of the shaft portion of each bolt 22 and the inner peripheral surface of each communication hole 108. As shown in FIGS. 2 and 3, the space formed by one bolt 22 (bolt 22A) and the communication hole 108 through which the bolt 22A is inserted is formed from the outside of the fuel cell stack 100 by the oxidant gas OG ( For example, air) is introduced and functions as an air electrode side gas supply manifold 161 which is a gas flow path for supplying the oxidant gas OG to the air chamber 166 of each power generation unit 102, and the other bolt 22 (bolt 22B). The space formed by the communication hole 108 through which the bolt 22B is inserted discharges the oxidant off-gas OOG, which is the gas discharged from the air chamber 166 of each power generation unit 102, to the outside of the fuel cell stack 100. It functions as an air electrode side gas discharge manifold 162. Further, as shown in FIGS. 2 and 4, the space formed by the other bolt 22 (bolt 22D) and the communication hole 108 through which the bolt 22D is inserted is fuel from the outside of the fuel cell stack 100. A gas FG (for example, a hydrogen-rich gas) is introduced, which functions as a fuel electrode side gas supply manifold 171 for supplying the fuel gas FG to the fuel chamber 176 of each power generation unit 102, and another one bolt 22 (bolt 22E). And the space formed by the communication hole 108 through which the bolt 22E is inserted is the fuel that discharges the fuel off-gas FOG, which is the gas discharged from the fuel chamber 176 of each power generation unit 102, to the outside of the fuel cell stack 100. It functions as a polar gas discharge manifold 172.

The fuel cell stack 100 is provided with four gas passage members 27. Each gas passage member 27 has a hollow cylindrical main body portion 28 and a hollow cylindrical branch portion 29 branched from the side surface of the main body portion 28. The hole of the branch portion 29 communicates with the hole of the main body portion 28. The holes in the main body 28 of each gas passage member 27 communicate with each manifold 161, 162, 171 and 172 provided at the installation position of each gas passage member 27.

(Structure of end plates 104 and 106)
The pair of end plates 104 and 106 are substantially rectangular flat plate-shaped conductive members, and are made of, for example, stainless steel. The upper end plate 104 functions as a positive output terminal of the fuel cell stack 100, and the lower end plate 106 functions as a negative output terminal of the fuel cell stack 100.

(Structure of power generation unit 102)
FIG. 5 is an explanatory diagram showing an XZ cross-sectional configuration of two power generation units 102 adjacent to each other at the same position as the cross section shown in FIG. 3, and FIG. 6 is an explanatory view showing the XZ cross-sectional configuration of the two power generation units 102 adjacent to each other at the same position as the cross section shown in FIG. It is explanatory drawing which shows the YZ cross-sectional structure of two power generation units 102.

As shown in FIGS. 5 and 6, the power generation unit 102 includes a single cell 110, a single cell separator 120, an air pole side frame member 130, an air pole side current collector 134, and a fuel pole side frame member 140. A fuel electrode side current collector 144, a pair of interconnectors 150, and a pair of IC separators 180 are provided. A hole corresponding to the communication hole 108 into which the bolt 22 described above is inserted is formed in the peripheral portion of the separator 120 for a single cell, the separator 180 for an IC, the frame member 130 on the air electrode side, and the frame member 140 on the fuel electrode side. ..

The interconnector 150 is a substantially rectangular flat plate-shaped conductive member, and is made of, for example, stainless steel. Further, the IC separator 180 is a frame-shaped member having a substantially rectangular through hole 181 penetrating in the vertical direction near the center, and is made of, for example, stainless steel. The portion of the IC separator 180 surrounding the through hole 181 is joined to the peripheral edge of the interconnector 150 by welding, for example. The interconnector 150 ensures electrical continuity between the power generation units 102. Further, the interconnector 150 and the IC separator 180 partition one of the air chamber 166 and the fuel chamber 176, and the other of the air chamber 166 and the fuel chamber 176 in the other power generation unit 102. In the present embodiment, when the two power generation units 102 are arranged adjacent to each other, one combination of the interconnector 150 and the IC separator 180 is shared by the two adjacent power generation units 102. That is, the combination of the upper interconnector 150 and the IC separator 180 in one power generation unit 102 is the combination of the lower interconnector 150 and the IC separator 180 in another power generation unit 102 adjacent to the upper side of the power generation unit 102. It is the same member. The IC separator 180 corresponds to the second separator in the claims.

The single cell 110 includes an electrolyte layer 112, an air electrode (cathode) 114 and a fuel electrode (anode) 116 that face each other in the vertical direction with the electrolyte layer 112 interposed therebetween. The electrolyte layer 112 is a substantially rectangular flat plate-shaped member, and is a dense layer. The electrolyte layer 112 is formed of, for example, a solid oxide such as YSZ (yttria-stabilized zirconia). As described above, the single cell 110 of the present embodiment is a solid oxide fuel cell (SOFC) using a solid oxide as an electrolyte. The air electrode 114 is a substantially rectangular flat plate-shaped member and is a porous layer. The air electrode 114 is formed of, for example, a perovskite-type oxide (for example, LSCF (lanthanum strontium cobalt iron oxide)). The fuel electrode 116 is a substantially rectangular flat plate-shaped member and is a porous layer. The fuel electrode 116 is formed of, for example, a cermet composed of Ni and oxide ion conductive ceramic particles (for example, YSZ).

The single cell separator 120 is a frame-shaped member having a substantially rectangular through hole 121 penetrating in the vertical direction near the center, and is made of, for example, stainless steel. The portion of the separator 120 for a single cell surrounding the through hole 121 is joined to the peripheral edge of the single cell 110 (electrolyte layer 112) by, for example, a joining portion 124 containing a brazing material. The single cell separator 120 separates the air chamber 166 facing the air pole 114 and the fuel chamber 176 facing the fuel pole 116. The single cell separator 120 corresponds to the first separator in the claims.

The air pole side frame member 130 is a frame-shaped member in which a substantially rectangular air chamber hole 131 is formed near the center, and is formed of, for example, an insulator such as mica. The air electrode side frame member 130 electrically insulates between the pair of IC separators 180 included in the power generation unit 102, and as a result, electrically insulates between the pair of interconnectors 150. The air electrode side frame member 130 has an oxidizing agent gas supply communication flow path 132 that communicates the air electrode side gas supply manifold 161 and the air chamber 166, and oxidation that communicates the air chamber 166 and the air electrode side gas discharge manifold 162. The agent gas discharge communication flow path 133 is formed.

The fuel electrode side frame member 140 is a frame-shaped member having a substantially rectangular fuel chamber hole 141 formed in the vicinity of the center, and is made of, for example, stainless steel. In the fuel electrode side frame member 140, the fuel gas supply communication flow path 142 that communicates the fuel electrode side gas supply manifold 171 and the fuel chamber 176, and the fuel gas that communicates the fuel chamber 176 and the fuel electrode side gas discharge manifold 172. A discharge communication flow path 143 is formed.

The air pole side current collector 134 is arranged in the air chamber 166. The air pole side current collector 134 is composed of a plurality of substantially square columnar current collector elements 135, and is made of, for example, stainless steel. The air electrode side current collector 134 electrically connects the air electrode 114 and the interconnector 150. However, since the power generation unit 102 located at the top of the fuel cell stack 100 does not have the upper interconnector 150, the air electrode side current collector 134 in the power generation unit 102 has the air electrode 114 and the end plate 104. Electrically connect (see FIGS. 3 and 4).

The fuel electrode side current collector 144 is arranged in the fuel chamber 176. The fuel electrode side current collector 144 includes an interconnector facing portion 146, an electrode facing portion 145, and a connecting portion 147 connecting the electrode facing portion 145 and the interconnector facing portion 146, for example, nickel or nickel alloy. , Stainless steel, etc. The electrode facing portion 145 is in contact with the surface of the fuel pole 116, the interconnector facing portion 146 is in contact with the surface of the interconnector 150, and as a result, the fuel pole side current collector 144 is in contact with the fuel pole 116. And the interconnector 150 are electrically connected. However, since the power generation unit 102 located at the bottom of the fuel cell stack 100 does not have the lower interconnector 150, the fuel pole side current collector 144 in the power generation unit 102 includes the fuel pole 116 and the end plate 106. Are electrically connected (see FIGS. 3 and 4). A spacer 149 formed of, for example, a mica is arranged between the electrode facing portion 145 and the interconnector facing portion 146.

A-3. Configuration of devices other than the fuel cell stack 100 in the fuel cell module 10:
Next, the configuration of the device other than the fuel cell stack 100 in the fuel cell module 10 will be described. As shown in FIG. 1, the fuel cell module 10 includes an auxiliary device 300 including an evaporator 310 and a reformer / heater 330, and various flow paths connecting the devices. The auxiliary device 300, together with the fuel cell stack 100, is housed in a heat insulating space 351 surrounded by a heat insulating material 350. In FIG. 1, for convenience, the flow of the gas on the fuel electrode side (including the raw fuel gas RFG, the fuel gas FG, and the fuel off gas FOG) is shown by a one-point chain line, and the gas on the air electrode side (oxidant gas OG and The flow of the oxidant off-gas OOG) is shown by a solid line, the flow of the exhaust gas EG is shown by a broken line, and the flow of water is shown by a two-point chain line.

The evaporator 310 is a box-shaped member having a space formed inside, and is formed of, for example, metal. The evaporator 310 is a device for evaporating pure water PW to generate steam. A pure water introduction flow path 251 for introducing pure water PW is connected to the evaporator 310. The pure water introduction flow path 251 is mainly composed of pipes, and an ion exchange resin 252, a water purification tank float 254, and a flow rate control mechanism 256 are provided on the pure water introduction flow path 251. The water WA supplied from the water supply source to the pure water introduction flow path 251 was purified and stored in the water purification tank float 254 after removal of calcium ions and the like in the ion exchange resin 252, and was controlled by the flow control mechanism 256. At the flow rate, it is introduced into the evaporator 310 as pure water PW.

Further, the evaporator 310 is connected to a raw fuel gas introduction flow path 261 for introducing the raw fuel gas RFG. The raw fuel gas introduction flow path 261 is mainly composed of pipes, and a flow control mechanism 262 and a hydrogenated desulfurizer 264 are provided on the raw material fuel gas introduction flow path 261. The raw fuel gas RFG supplied from the gas source to the raw fuel gas introduction flow path 261 is introduced into the evaporator 310 at a flow rate controlled by the flow rate control mechanism 262 in a state where the sulfur component is removed in the hydrogenated desulfurizer 264. Will be done.

Further, the evaporator 310 includes an exhaust gas relay flow path 226 for sending exhaust gas EG from the housing 335 (described later) of the reformer / heater 330 to the evaporator 310, and a modification of the reformer / heater 330 from the evaporator 310. A mixed gas flow path 228 for sending the mixed gas to the pawn 331 (described later) and an exhaust gas discharge flow path 223 for discharging the exhaust gas EG from the evaporator 310 are connected. These flow paths are mainly composed of pipes.

The reformer / heater 330 includes a reformer 331, a combustor 333, and a housing 335. The housing 335 is, for example, a closed container made of metal and houses the reformer 331 and the combustor 333. The housing 335 is configured in a double wall structure having an inner wall 336 and an outer wall 337, and heat transfer fins 339 are arranged in an air flow path 338 formed between the inner wall 336 and the outer wall 337. There is. In FIG. 1, for convenience, a part of the heat transfer fin 339 is not shown. An air introduction flow path 271 for introducing the oxidant gas OG (air) is connected to the housing 335. The air introduction flow path 271 is mainly composed of pipes, and a flow rate control mechanism 272 is provided on the air introduction flow path 271. The oxidant gas OG supplied to the air introduction flow path 271 is introduced into the air flow path 338 of the housing 335 at a flow rate controlled by the flow rate control mechanism 272. Further, the housing 335 is connected to an air electrode side gas supply flow path 61 for sending out the oxidant gas OG toward the air electrode side gas supply manifold 161 of the fuel cell stack 100. The gas supply flow path 61 on the air electrode side is mainly composed of pipes.

The reformer 331 is a box-shaped member having a space formed inside, and is formed of, for example, metal. The reformer 331 is a device for reforming the raw fuel gas RFG to generate the fuel gas FG. A catalyst that promotes the reforming reaction may be arranged in the reformer 331. As described above, the reformer 331 is connected to the mixed gas flow path 228 for sending the mixed gas from the evaporator 310 to the reformer 331. Further, the reformer 331 is connected to a fuel electrode side gas supply flow path 71 for sending out the fuel gas FG toward the fuel electrode side gas supply manifold 171 of the fuel cell stack 100. The gas supply flow path 71 on the fuel electrode side is mainly composed of pipes.

The combustor 333 is a box-shaped member having a space formed inside, and is formed of, for example, metal. The combustor 333 is a device for burning the oxidant off-gas OOG and the fuel off-gas FOG. A catalyst that promotes combustion of the oxidant off-gas OOG and the fuel off-gas FOG may be arranged in the combustor 333. In the combustor 333, fuel is supplied from the air electrode side gas discharge flow path 240 to which the oxidant off gas OOG is sent out from the air electrode side gas discharge manifold 162 of the fuel cell stack 100, and the fuel electrode side gas discharge manifold 172 of the fuel cell stack 100. It is connected to the fuel electrode side gas discharge flow path 230 to which the off-gas FOG is sent out. These flow paths are mainly composed of pipes. The configuration of the fuel electrode side gas discharge flow path 230 will be described in detail later.

A-4. Operation of fuel cell module 10:
Next, the operation of the fuel cell module 10 will be described. As shown in FIG. 1, the oxidant gas OG introduced into the air flow path 338 formed in the housing 335 of the reformer / heater 330 via the air introduction flow path 271 was generated by the combustor 333. It flows through the air flow path 338 while being heated by the combustion heat (exhaust gas exhaust gas EG), and is supplied to the air pole side gas supply manifold 161 of the fuel cell stack 100 via the air pole side gas supply flow path 61. As shown in FIGS. 3 and 5, the oxidant gas OG supplied to the air electrode side gas supply manifold 161 passes through the oxidant gas supply communication flow path 132 of each power generation unit 102 from the air electrode side gas supply manifold 161. It is supplied to the air chamber 166 via the air chamber 166. Further, as shown in FIG. 1, the raw fuel gas RFG is supplied to the evaporator 310 via the raw fuel gas introduction flow path 261 and the pure water PW is supplied to the evaporator 310 via the pure water introduction flow path 251. When supplied, in the evaporator 310, water vapor is generated by evaporating the pure water PW using the heat of the exhaust gas EG introduced through the exhaust gas relay flow path 226, and this water vapor is used as the raw fuel gas. Mix with RFG. The raw fuel gas RFG mixed with steam is introduced from the evaporator 310 to the reformer 331 via the mixed gas flow path 228 and steam reformed in the reformer 331, resulting in a hydrogen-rich fuel gas FG. Is generated. The generated fuel gas FG is supplied to the fuel electrode side gas supply manifold 171 of the fuel cell stack 100 via the fuel electrode side gas supply flow path 71. As shown in FIGS. 4 and 6, the fuel gas FG supplied to the fuel electrode side gas supply manifold 171 is transmitted from the fuel electrode side gas supply manifold 171 via the fuel gas supply communication flow path 142 of each power generation unit 102. It is supplied to the fuel chamber 176.

When the oxidant gas OG is supplied to the air chamber 166 of each power generation unit 102 and the fuel gas FG is supplied to the fuel chamber 176, oxygen and fuel gas contained in the oxidant gas OG in the single cell 110 of each power generation unit 102 are supplied. Power is generated by an electrochemical reaction with hydrogen contained in FG. This power generation reaction is an exothermic reaction. In each power generation unit 102, the air pole 114 of the single cell 110 is electrically connected to one of the interconnectors 150 via the air pole side current collector 134, and the fuel pole 116 is via the fuel pole side current collector 144. It is electrically connected to the other interconnector 150. Further, the plurality of power generation units 102 included in the fuel cell stack 100 are electrically connected in series. Therefore, the electric energy generated in each power generation unit 102 is taken out from the end plates 104 and 106 that function as the output terminals of the fuel cell stack 100. The SOFC generates electricity at a relatively high temperature (for example, 700 ° C to 1000 ° C).

As shown in FIGS. 1, 3 and 5, the oxidant off-gas OOG discharged from the air chamber 166 of each power generation unit 102 to the air electrode side gas discharge manifold 162 via the oxidant gas discharge communication flow path 133 is It is introduced into the combustor 333 via the gas discharge flow path 240 on the air electrode side. Further, as shown in FIGS. 1 and 4, the fuel off-gas FOG discharged from the fuel chamber 176 of each power generation unit 102 to the fuel electrode side gas discharge manifold 172 via the fuel gas discharge communication flow path 143 is a fuel. It is introduced into the combustor 333 via the polar side gas discharge flow path 230. The oxidant off-gas OOG and fuel off-gas FOG introduced into the combustor 333 are mixed and burned in the combustor 333, and then discharged as exhaust gas EG to the evaporator 310 via the exhaust gas relay flow path 226. The heat generated in the combustor 333 accelerates the reforming reaction in the reformer 331 and heats the fuel cell stack 100. The exhaust gas EG introduced into the evaporator 310 is discharged to the hot water storage unit 290 via the exhaust gas discharge flow path 223, and is used for heating the water WA supplied from the water supply source to the hot water storage unit 290 via the water supply flow path 259. Will be done.

A-5. Detailed configuration of the fuel electrode side gas discharge flow path 230:
Next, the detailed configuration of the fuel electrode side gas discharge flow path 230 will be described. As described above, the fuel pole side gas discharge flow path 230 is a flow path connecting the fuel pole side gas discharge manifold 172 of the fuel cell stack 100 and the combustor 333. As shown in FIG. 1, the fuel pole side gas discharge flow path 230 is the first pipe 231 connecting the drainer 234, the pressure control mechanism 236, the fuel pole side gas discharge manifold 172 of the fuel cell stack 100, and the drainer 234. It has a second pipe 235 for connecting the drainer 234 and the pressure control mechanism 236, and a third pipe 237 for connecting the pressure control mechanism 236 and the combustor 333. A blower BL is provided on the third pipe 237.

Here, in the present embodiment, a part of the fuel electrode side gas discharge flow path 230 is arranged outside the heat insulating space 351 surrounded by the heat insulating material 350. More specifically, a part of the downstream side of the first pipe 231, a drainer 234, a second pipe 235, a pressure control mechanism 236, and a part of the upstream side of the third pipe 237 are the heat insulating space 351. It is located outside of. Since a part of the downstream side of the first pipe 231 described above is arranged outside the heat insulating space 351, it functions as a cooling mechanism 232 for cooling the gas in the fuel electrode side gas discharge flow path 230. That is, the relatively high temperature (for example, about 600 ° C. to 700 ° C.) fuel off-gas FOG discharged from the fuel pole side gas discharge manifold 172 of the fuel cell stack 100 constitutes the fuel pole side gas discharge flow path 230. It is introduced into one pipe 231 and is cooled to a predetermined temperature or less (for example, 100 ° C. or less) in a portion (cooling mechanism 232) arranged outside the heat insulating space 351 in the first pipe 231. The condensed water generated by being cooled by the cooling mechanism 232 is removed by the drainer 234. The condensed water removed by the drainer 234 is introduced into the ion exchange resin 252 on the pure water introduction flow path 251 via the condensed water recovery flow path 258. The fuel electrode side gas discharge flow path 230 corresponds to a specific gas discharge flow path within the scope of claims.

The pressure control mechanism 236 is composed of a pressure control valve and is a device for adjusting the pressure of the fuel off-gas FOG in the fuel electrode side gas discharge flow path 230. The pressure control mechanism 236 is located on the downstream side of the cooling mechanism 232 and the drainer 234. Further, the fuel cell module 10 includes a fuel pole side pressure gauge 238 for measuring the pressure of the fuel pole side gas flow path and an air pole side pressure gauge 248 for measuring the pressure of the air pole side gas flow path. Here, the fuel pole side gas flow path means a flow path through which gas flows on the fuel pole side, and at least the fuel pole side gas supply flow path 71, the fuel pole side gas supply manifold 171 and the fuel chamber 176 of each power generation unit 102. It is a flow path including the fuel pole side gas discharge manifold 172 and the fuel pole side gas discharge flow path 230. In the present embodiment, the fuel electrode side gas flow path is the mixed gas flow path 228, the fuel pole side gas supply flow path 71, and each power generation unit from the downstream side of the flow control mechanism 262 in the raw fuel gas introduction flow path 261. It is the entire gas flow path from the fuel chamber 176 of 102 to the combustor 333. Further, the gas flow path on the air pole side means a flow path through which gas flows on the air pole side, and at least the gas supply flow path 61 on the air pole side, the gas supply manifold 161 on the air pole side, and the air chamber 166 of each power generation unit 102. It is a flow path including the air pole side gas discharge manifold 162 and the air pole side gas discharge flow path 240. In the present embodiment, the air electrode side gas flow path is the air of the air flow path 338, the air pole side gas supply flow path 61, and each power generation unit 102 from the downstream side of the flow control mechanism 272 in the air introduction flow path 271. It is the entire gas flow path from the chamber 166 to the combustor 333. In the present embodiment, the fuel pole side pressure gauge 238 is provided in the fuel pole side gas discharge flow path 230 in the fuel pole side gas flow path, and the air pole side pressure gauge 248 is the air pole side gas flow path. Of these, it is provided in the gas discharge flow path 240 on the air electrode side. The fuel pole side pressure gauge 238 and the air pole side pressure gauge 248 correspond to the pressure measuring unit in the claims.

Further, the fuel cell module 10 includes a control unit 280 that controls the pressure control mechanism 236 based on the pressure measurement results by the fuel pole side pressure gauge 238 and the air pole side pressure gauge 248. The control unit 280 controls the pressure control mechanism 236 so that the difference between the pressure of the gas flow path on the fuel pole side and the pressure of the gas flow path on the air pole side does not become excessive. For example, when the flow rate of the gas supplied to the air electrode side gas supply manifold 161 is increased in order to lower the temperature of the fuel cell stack 100, the pressure in the air electrode side gas flow path increases. As a result, when it is predicted that the difference between the pressure of the gas flow path on the fuel pole side and the pressure of the gas flow path on the air pole side will be excessive, the control unit 280 will use the valve constituting the pressure control mechanism 236. By operating in the closing direction, the pressure of the gas flow path on the fuel pole side is increased, and the difference between the pressure of the gas flow path on the fuel pole side and the pressure of the gas flow path on the air pole side is suppressed from becoming excessive. On the contrary, when the flow rate of the gas supplied to the air electrode side gas supply manifold 161 is reduced in order to raise the temperature of the fuel cell stack 100, the pressure in the air electrode side gas flow path becomes low. As a result, when it is predicted that the difference between the pressure of the gas flow path on the fuel pole side and the pressure of the gas flow path on the air pole side will be excessive, the control unit 280 will use the valve constituting the pressure control mechanism 236. By operating in the opening direction, the pressure of the gas flow path on the fuel pole side is lowered, and the difference between the pressure of the gas flow path on the fuel pole side and the pressure of the gas flow path on the air pole side is suppressed from becoming excessive.

In the present embodiment, the position of the fuel electrode side gas discharge flow path 230 on the downstream side of the cooling mechanism 232 (in the present embodiment, on the downstream side of the pressure control mechanism 236) and the branch connecting the hydrogenated desulfurizer 264. A flow path 242 is provided. A blower BL is provided on the branch flow path 242. The fuel off-gas FOG is supplied to the hydrogenated desulfurizer 264 through the branch flow path 242 and used for the desulfurization treatment in the hydrogenated desulfurizer 264. In this embodiment, since the blower BL is provided on the branch flow path 242, it is possible to control the distribution of the fuel off gas flowing through the hydrogenated desulfurizer 264 and the fuel off gas flowing through the combustor 333.

A-6. Effect of the first embodiment:
As described above, the fuel cell module 10 of the present embodiment includes the fuel cell stack 100. The fuel cell stack 100 includes a plurality of power generation units 102 each having a single cell 110 including an air pole 114 and a fuel pole 116 facing each other across the electrolyte layer 112 and the electrolyte layer 112. The fuel cell stack 100 includes a fuel pole side gas supply manifold 171 that supplies gas to the fuel chamber 176 in each power generation unit 102, and a fuel pole side gas discharge manifold 172 that discharges gas from the fuel chamber 176 in each power generation unit 102. An air pole side gas supply manifold 161 for supplying gas to the air chamber 166 in each power generation unit 102 and an air pole side gas discharge manifold 162 for discharging gas from the air chamber 166 in each power generation unit 102 are formed. Further, the fuel cell module 10 includes a combustor 333 that burns gas, a fuel pole side gas discharge flow path 230 that connects the fuel pole side gas discharge manifold 172 of the fuel cell stack 100 and the combustor 333, and a fuel cell stack. It is provided with an air pole side gas discharge flow path 240 for connecting the air pole side gas discharge manifold 162 of 100 and the combustor 333. Further, in the fuel pole side gas discharge flow path 230, a cooling mechanism 232 for cooling the gas in the fuel pole side gas discharge flow path 230 and a cooling mechanism 232 arranged on the downstream side of the cooling mechanism 232 are arranged on the fuel pole side gas discharge flow path 230. A pressure control mechanism 236 for adjusting the pressure of the gas inside is provided.

As described above, in the fuel cell module 10 of the present embodiment, the fuel electrode side gas discharge flow path 230 is provided with a cooling mechanism 232 for cooling the gas in the fuel pole side gas discharge flow path 230, so that the fuel electrode is provided. A general-purpose pressure control mechanism 236 for adjusting the pressure of the gas in the fuel electrode side gas discharge flow path 230 on the downstream side of the cooling mechanism 232 in the side gas discharge flow path 230, which does not have special heat resistance performance. A pressure control mechanism 236 can be provided. Further, in the fuel cell module 10 of the present embodiment, the pressure of the gas in the fuel electrode side gas discharge flow path 230 is adjusted by the pressure control mechanism 236 to obtain the pressure of the air electrode side gas flow path in each power generation unit 102. It is possible to prevent the difference from the pressure of the gas flow path on the fuel electrode side from becoming excessive. Therefore, according to the fuel cell module 10 of the present embodiment, due to the pressure difference between the gas flow path on the air pole side and the gas flow path on the fuel pole side, the gas flow path on the air pole side or the fuel pole side in each power generation unit 102 It is possible to prevent the members constituting the gas flow path from being deformed and the pressure loss of the gas flow path on the air pole side or the gas flow path on the fuel pole side in each power generation unit 102 to be large and the gas distribution property to be deteriorated. It is possible to suppress deterioration, deterioration, and damage of the single cell 110 due to deterioration of gas distributability.

Further, the fuel cell module 10 of the present embodiment further includes a fuel electrode side gas supply flow path 71 connected to the fuel electrode side gas supply manifold 171 of the fuel cell stack 100 and an air electrode side gas supply of the fuel cell stack 100. The air electrode side gas supply flow path 61 connected to the manifold 161 is provided. Further, the fuel cell module 10 has at least an air pole side gas supply flow path 61, an air pole side gas supply manifold 161, an air chamber 166 of each power generation unit 102, an air pole side gas discharge manifold 162, and an air pole side gas discharge flow path. An air electrode side pressure gauge 248 that measures the pressure of the air electrode side gas flow path including 240, at least the fuel electrode side gas supply flow path 71, the fuel electrode side gas supply manifold 171 and the fuel chamber 176 of each power generation unit 102. Fuel pole side pressure gauge 238, air pole side pressure gauge 248 and fuel pole side pressure gauge to measure the pressure of the fuel pole side gas flow path including the fuel pole side gas discharge manifold 172 and the fuel pole side gas discharge flow path 230. A control unit 280 that controls the pressure control mechanism 236 based on the pressure measurement result by the 238 is provided. Therefore, according to the fuel cell module 10 of the present embodiment, the difference between the pressure of the gas flow path on the air electrode side and the pressure of the gas flow path on the fuel electrode side in each power generation unit 102 becomes excessive by using the pressure control mechanism 236. This can be effectively suppressed, and the deterioration, deterioration, and damage of the single cell 110 due to the deterioration of the gas distribution property can be effectively suppressed.

Further, the fuel cell module 10 of the present embodiment further includes a hydrogenated desulfurizer 264 for desulfurizing the raw fuel gas RFG, a position downstream of the cooling mechanism 232 in the fuel electrode side gas discharge flow path 230, and hydrogenated desulfurization. It is provided with a branch flow path 242 that connects to the vessel 264. Therefore, according to the fuel cell module 10 of the present embodiment, the fuel off-gas FOG discharged from the fuel cell stack 100 can be used for desulfurization of the raw fuel gas RFG, and the system efficiency can be improved.

Further, in the fuel cell module 10 of the present embodiment, each power generation unit 102 further has a single cell separator 120. A through hole 121 is formed in the single cell separator 120, and a portion of the single cell separator 120 surrounding the through hole 121 is joined to the peripheral edge of the single cell 110, and as a result, the single cell separator 120 is formed. Separates the air chamber 166 and the fuel chamber 176. The fuel cell module 10 of the present embodiment has a configuration in which deterioration of gas distributability is likely to occur due to deformation of the single cell separator 120 joined to the single cell 110, but each power generation unit uses the pressure control mechanism 236. Since it is possible to suppress an excessive difference between the pressure of the gas flow path on the air electrode side and the pressure of the gas flow path on the fuel electrode side in 102, it is possible to suppress the deformation of the separator 120 for a single cell due to the pressure difference. Therefore, it is possible to suppress deterioration, deterioration, and damage of the single cell 110 due to deterioration of gas distributability.

Further, in the fuel cell module 10 of the present embodiment, each power generation unit 102 further has an IC separator 180. A through hole 181 is formed in the IC separator 180, and a portion of the IC separator 180 surrounding the through hole 181 is joined to the peripheral edge of the interconnector 150. As a result, the IC separator 180 is made of air. One of the chamber 166 and the fuel chamber 176 and the other of the air chamber 166 and the fuel chamber 176 in the other power generation unit 102 are partitioned. The fuel cell module 10 of the present embodiment has a configuration in which deterioration of gas distributability is likely to occur due to deformation of the IC separator 180 joined to the interconnector 150, but each power generation unit 102 uses the pressure control mechanism 236. Since it is possible to suppress an excessive difference between the pressure of the gas flow path on the air electrode side and the pressure of the gas flow path on the fuel electrode side in the above, it is possible to suppress the deformation of the IC separator 180 due to the pressure difference. It is possible to suppress deterioration, deterioration, and damage of the single cell 110 due to deterioration of gas distributability.

The cooling of the fuel off-gas FOG by the cooling mechanism 232 of the fuel electrode side gas discharge flow path 230 is preferably cooled to a temperature equal to or lower than the temperature at which the water vapor contained in the fuel off-gas FOG condenses. By doing so, the water contained in the fuel off-gas FOG can be removed, the fuel concentration of the fuel off-gas FOG becomes high, and the combustion performance in the combustor 333 becomes good.

Further, the length of the portion located in the heat insulating space 351 in the third pipe 237 constituting the fuel electrode side gas discharge flow path 230 is preferably long. If the length of the portion is long, the temperature of the fuel off-gas FOG flowing through the portion can be raised by the heat in the heat insulating space 351 (for example, the heat radiated from the fuel cell stack 100). It is possible to suppress a decrease in efficiency due to a decrease in temperature of the introduced fuel off-gas FOG. For example, the length of the portion located in the heat insulating space 351 in the third pipe 237 constituting the fuel electrode side gas discharge flow path 230 is set to the portion located outside the heat insulating space 351 in the third pipe 237. 2 It may be longer than the total length with the length of the pipe 235. Further, the portion located in the heat insulating space 351 in the third pipe 237 constituting the fuel electrode side gas discharge flow path 230 is close to and parallel to the portion located in the heat insulating space 351 in the first pipe 231. It is preferable that they are arranged so as to do so. A relatively high temperature fuel off-gas FOG flows in a portion of the first pipe 231 located in the heat insulating space 351. Therefore, if the portion located in the heat insulating space 351 in the third pipe 237 is arranged so as to be close to and parallel to the portion located in the heat insulating space 351 in the first pipe 231, the inside of the first pipe 231 is arranged. The temperature of the fuel off-gas FOG flowing through the portion located in the heat insulating space 351 in the third pipe 237 can be raised by the heat of the fuel off-gas FOG flowing through the portion located in the heat insulating space 351 of the third pipe 237. It is possible to suppress a decrease in efficiency due to a decrease in the temperature of the fuel off-gas FOG to be introduced. Alternatively, a part of the third pipe 237 constituting the fuel electrode side gas discharge flow path 230 may be insulated by extending the inside of the heat insulating material 350 or the like.

B. Second embodiment:
FIG. 7 is an explanatory diagram schematically showing the configuration of the fuel cell module 10a in the second embodiment. Hereinafter, among the configurations of the fuel cell module 10a of the second embodiment, the same configurations as those of the fuel cell module 10 of the first embodiment described above will be appropriately described by adding the same reference numerals.

The fuel cell module 10a of the second embodiment is different from the fuel cell module 10 of the first embodiment in the configuration of the cooling mechanism 232a in the fuel electrode side gas discharge flow path 230. Specifically, in the fuel cell module 10a of the second embodiment, the cooling mechanism 232a in the fuel electrode side gas discharge flow path 230 includes the heat exchange unit 233. That is, in the present embodiment, a part of the air introduction flow path 271a for introducing the oxidant gas OG into the housing 335 is outside the heat insulating space 351 in the first pipe 231 constituting the fuel electrode side gas discharge flow path 230. It is arranged so as to be close to and parallel to the part arranged in. As a result, the portion of the first pipe 231 (the portion parallel to the air introduction flow path 271a) becomes the oxidant gas OG (gas for supplying to the air electrode side gas supply manifold 161) and the fuel electrode side gas discharge flow path. It functions as a heat exchange unit 233 that exchanges heat with the fuel off-gas FOG in 230. In the heat exchange unit 233, heat exchange between the oxidant gas OG and the fuel off gas FOG is performed, the temperature of the fuel off gas FOG introduced in the pressure control mechanism 236 is lowered, and the oxidant gas introduced in the housing 335 is reduced. The temperature of OG rises.

As described above, in the fuel cell module 10a of the present embodiment, the cooling mechanism 232a provided in the fuel electrode side gas discharge flow path 230 supplies the gas (oxidizer gas OG) to the air electrode side gas supply manifold 161. Includes a heat exchange unit 233 that exchanges heat between the gas and the gas (fuel off gas FOG) in the fuel electrode side gas discharge flow path 230. Therefore, in the heat exchange unit 233, the gas supplied to the air electrode side gas supply manifold 161 takes heat of the gas in the fuel electrode side gas discharge channel 230, thereby taking the heat of the gas in the fuel electrode side gas discharge channel 230 into the fuel electrode side gas discharge channel 230. Gas is cooled. Therefore, according to the fuel cell module 10a of the present embodiment, the entire fuel cell module 10a is provided with the cooling mechanism 232a while realizing the cooling of the gas in the fuel electrode side gas discharge flow path 230 by the cooling mechanism 232a. It is possible to suppress a decrease in thermal efficiency.

C. Third embodiment:
FIG. 8 is an explanatory diagram schematically showing the configuration of the fuel cell module 10b according to the third embodiment. Hereinafter, among the configurations of the fuel cell module 10b of the third embodiment, the same configurations as those of the fuel cell module 10 of the first embodiment described above will be appropriately described by adding the same reference numerals.

The fuel cell module 10b of the third embodiment is different from the fuel cell module 10 of the first embodiment in the configuration of the cooling mechanism 232b in the fuel electrode side gas discharge flow path 230. Specifically, in the fuel cell module 10b of the third embodiment, the cooling mechanism 232b in the fuel electrode side gas discharge flow path 230 includes the heat exchange unit 233b. That is, in the present embodiment, a part of the pure water introduction flow path 251b for supplying water WA to the evaporator 310 is outside the heat insulating space 351 in the first pipe 231 constituting the fuel electrode side gas discharge flow path 230. It is arranged so as to be close to and parallel to the part arranged in. As a result, the portion of the first pipe 231 (the portion parallel to the pure water introduction flow path 251b) is between the water WA supplied to the evaporator 310 and the fuel off-gas FOG in the fuel electrode side gas discharge flow path 230. It functions as a heat exchange unit 233b for heat exchange. In the heat exchange unit 233b, heat exchange between the water WA and the fuel off-gas FOG is performed, the temperature of the fuel off-gas FOG introduced in the pressure control mechanism 236 is lowered, and the water WA (pure) introduced in the evaporator 310 is lowered. The temperature of water PW) rises.

As described above, in the fuel cell module 10b of the present embodiment, the cooling mechanism 232b provided in the fuel pole side gas discharge flow path 230 is inside the water WA supplied to the evaporator 310 and the fuel pole side gas discharge flow path 230. Includes a heat exchange unit 233b that exchanges heat with the gas (fuel off gas FOG). Therefore, in the heat exchange unit 233b, the water WA supplied to the evaporator 310 takes heat of the gas in the fuel electrode side gas discharge channel 230, so that the gas in the fuel electrode side gas discharge channel 230 is cooled. Will be done. Therefore, according to the fuel cell module 10b of the present embodiment, the entire fuel cell module 10b is provided with the cooling mechanism 232b while realizing the cooling of the gas in the fuel electrode side gas discharge flow path 230 by the cooling mechanism 232b. It is possible to suppress a decrease in thermal efficiency.

D. Fourth Embodiment:
FIG. 9 is an explanatory diagram schematically showing the configuration of the fuel cell module 10c according to the fourth embodiment. Hereinafter, among the configurations of the fuel cell module 10c of the fourth embodiment, the same configurations as those of the fuel cell module 10 of the first embodiment described above will be appropriately described by adding the same reference numerals.

The fuel cell module 10c of the fourth embodiment is different from the fuel cell module 10 of the first embodiment in the configuration of the cooling mechanism 232c in the fuel electrode side gas discharge flow path 230. Specifically, in the fuel cell module 10c of the fourth embodiment, the cooling mechanism 232c in the fuel electrode side gas discharge flow path 230 includes the heat exchange unit 233c. That is, in the present embodiment, a part of the raw fuel gas introduction flow path 261c for introducing the raw material fuel gas RFG into the evaporator 310 is a heat insulating space in the first pipe 231 constituting the fuel electrode side gas discharge flow path 230. It is arranged so as to be close to and parallel to the portion arranged outside the 351. As a result, the portion of the first pipe 231 (the portion parallel to the raw fuel gas introduction flow path 261c) becomes the raw fuel gas RFG (gas for supplying to the fuel electrode side gas supply manifold 171) and the fuel electrode side gas discharge. It functions as a heat exchange unit 233c that exchanges heat with the fuel off-gas FOG in the flow path 230. In the heat exchange unit 233c, heat exchange between the raw fuel gas RFG and the fuel off-gas FOG is performed, the temperature of the fuel off-gas FOG introduced in the pressure control mechanism 236 is lowered, and the raw material and fuel introduced in the evaporator 310 are lowered. The temperature of the gas RFG rises.

As described above, in the fuel cell module 10c of the present embodiment, the cooling mechanism 232c provided in the fuel electrode side gas discharge flow path 230 supplies the gas (raw fuel gas RFG) to the fuel electrode side gas supply manifold 171. Includes a heat exchange unit 233c that exchanges heat between and the gas (fuel off gas FOG) in the fuel electrode side gas discharge flow path 230. Therefore, in the heat exchange unit 233c, the gas supplied to the fuel electrode side gas supply manifold 171 takes heat of the gas in the fuel electrode side gas discharge channel 230, thereby taking the heat of the gas in the fuel electrode side gas discharge channel 230 into the fuel electrode side gas discharge channel 230. Gas is cooled. Therefore, according to the fuel cell module 10c of the present embodiment, the entire fuel cell module 10c is provided with the cooling mechanism 232c while realizing the cooling of the gas in the fuel electrode side gas discharge flow path 230 by the cooling mechanism 232c. It is possible to suppress a decrease in thermal efficiency.

E. Modification example:
The technique disclosed in the present specification is not limited to the above-described embodiment, and can be transformed into various forms without departing from the gist thereof, and for example, the following modifications are also possible.

The configuration of the fuel cell module 10 and the configuration of each part constituting the fuel cell module 10 in the above embodiment are merely examples and can be variously modified. For example, in the above embodiment, the cooling mechanism 232 and the pressure control mechanism 236 are provided on the fuel pole side gas discharge flow path 230, but instead of the fuel pole side gas discharge flow path 230 or the fuel pole side gas. A cooling mechanism and a pressure control mechanism may be provided on the air electrode side gas discharge flow path 240 as well as on the discharge flow path 230. Of the fuel pole side gas discharge flow path 230 and the air pole side gas discharge flow path 240, the flow path provided with the cooling mechanism and the pressure control mechanism corresponds to the specific gas discharge flow path within the scope of the claims. In general, the gas flow rate in the fuel electrode side gas flow path is often smaller than the gas flow rate in the air electrode side gas flow path. Therefore, from the viewpoint of suppressing a decrease in the thermal efficiency of the fuel cell module 10, the fuel electrode side gas It is preferable that the cooling mechanism 232 and the pressure control mechanism 236 are provided only in the discharge flow path 230.

The configuration of the cooling mechanism 232 in the above embodiment is merely an example and can be variously modified. For example, in the above 2-4 embodiment, the cooling mechanism 232 adopts a configuration including a heat exchange unit 233 that exchanges heat with the oxidant gas OG, water WA, or raw fuel gas RFG. As the cooling mechanism 232, a configuration including a heat exchange unit that exchanges heat with another fluid may be adopted. Further, in the above embodiment, the pressure control mechanism 236 is configured by the pressure control valve, but the pressure control mechanism 236 may have another configuration.

In the above embodiment, the fuel pole side pressure gauge 238 is provided at the position of the fuel pole side gas discharge flow path 230 in the fuel pole side gas flow path, but the fuel pole side pressure gauge 238 in the fuel pole side gas flow path. The installation position of is arbitrarily changeable. For example, the fuel electrode side pressure gauge 238 may be provided at a position downstream of the flow control mechanism 262 in the raw fuel gas introduction flow path 261 and at a position upstream of the hydrogenated desulfurizer 264. Similarly, in the above embodiment, the air pole side pressure gauge 248 is provided at the position of the air pole side gas discharge flow path 240 in the air pole side gas flow path, but the air pole side in the air pole side gas flow path. The installation position of the pressure gauge 248 can be changed arbitrarily. For example, the air pole side pressure gauge 248 may be provided on the downstream side of the flow rate control mechanism 272 in the air introduction flow path 271 and at a position outside the heat insulating material 350 (heat insulating space 351). Further, only one of the fuel pole side pressure gauge 238 and the air pole side pressure gauge 248 may be provided. Even with such a configuration, for example, by specifying the relationship between the gas flow rate and the pressure change in advance, the pressure control mechanism 236 can be appropriately controlled based on the pressure measurement result by the pressure gauge.

In the above embodiment, the branch flow path 242 is provided so as to connect the position downstream of the cooling mechanism 232 and the pressure control mechanism 236 in the fuel electrode side gas discharge flow path 230 to the hydrogenated desulfurizer 264. The branch flow path 242 is provided so as to connect the position on the downstream side of the cooling mechanism 232 in the fuel electrode side gas discharge flow path 230 and the upstream side of the pressure control mechanism 236 to the hydrogenated desulfurizer 264. May be good.

In the above embodiment, each power generation unit 102 includes a single cell separator 120 and an IC separator 180, but each power generation unit 102 includes one or both of the single cell separator 120 and the IC separator 180. It may not be. For example, each power generation unit 102 does not have an IC separator 180, and the interconnector 150 extends to the peripheral edge portion of the power generation unit 102 (a portion that overlaps the air pole side frame member 130 and the fuel pole side frame member 140 in the Z-axis direction). You may be doing it.

In the above embodiment, the blower BL for supplying the fuel off gas to the hydrogenated desulfurizer 264 is provided on the branch flow path 242, and the blower BL is the flow control mechanism 262 on the raw fuel gas introduction flow path 261. It may be provided between the hydrogenated desulfurizer 264 and the hydrogenated desulfurizer 264. Alternatively, the installation of the blower BL may be omitted. Even if the installation of the blower BL is omitted, by making the inner diameter of the pipe of the branch flow path 242 smaller than the inner diameter of the third pipe 237 of the fuel electrode side gas discharge flow path 230, the off gas flowing to the hydrogenated desulfurizer 264 can be obtained. It is possible to control the distribution with the off gas flowing through the combustor 333.

From the second embodiment to the fourth embodiment, the heat exchange units 233, 233b and 233c are arranged outside the heat insulating space 351 but a part or all of the heat exchange units 233, 233b and 233c are heat insulating spaces. It may be arranged in 351.

In the above embodiment, the solid oxide fuel cell (SOFC) has been described as an example, but the technique disclosed in the present specification is also applicable to other types of fuel cells such as molten carbonate fuel cell (MCFC). It is possible.

10: Fuel cell module 22: Bolt 24: Nut 26: Insulation sheet 27: Gas passage member 28: Main body 29: Branch 61: Air pole side gas supply flow path 71: Fuel pole side gas supply flow path 100: Fuel cell Stack 102: Power generation unit 104: End plate 106: End plate 108: Communication hole 110: Single cell 112: Electrolyte layer 114: Air pole 116: Fuel pole 120: Single cell separator 121: Through hole 124: Joint 130: Air Pole side frame member 131: Air chamber hole 132: Oxidating agent gas supply communication flow path 133: Oxidizing agent gas discharge communication flow path 134: Air pole side current collector 135: Current collector element 140: Fuel pole side frame member 141 : Fuel chamber hole 142: Fuel gas supply communication flow path 143: Fuel gas discharge communication flow path 144: Fuel electrode side current collector 145: Electrode facing part 146: Interconnector facing part 147: Connecting part 149: Spacer 150: Inter Connector 161: Air pole side gas supply manifold 162: Air pole side gas discharge manifold 166: Air chamber 171: Fuel pole side gas supply manifold 172: Fuel pole side gas discharge manifold 176: Fuel chamber 180: IC separator 181: Through hole 223: Exhaust gas discharge flow path 226: Exhaust gas relay flow path 228: Mixed gas flow path 230: Fuel electrode side gas discharge flow path 231: First pipe 232: Cooling mechanism 233: Heat exchange unit 234: Drainer 235: Second pipe 236 : Pressure control mechanism 237: Third pipe 238: Fuel pole side pressure gauge 240: Air pole side gas discharge flow path 242: Branch flow path 248: Air pole side pressure gauge 251: Pure water introduction flow path 252: Ion exchange resin 254 : Water purification tank float 256: Flow control mechanism 258: Condensed water recovery flow path 259: Water supply flow path 261: Raw fuel gas introduction flow path 262: Flow control mechanism 264: Hydrogenated desulfurizer 271: Air introduction flow path 272: Flow control mechanism 280: Control unit 290: Hot water storage unit 300: Auxiliary device 310: Evaporator 330: Reformer / heater 331: Reformer 333: Combustor 335: Housing 336: Inner wall 337: Outer wall 338: Air flow path 339 : Heat transfer fuel 350: Insulation material 351: Insulation space BL: Blower EG: Exhaust gas FG: Fuel gas FOG: Fuel off gas OG: Oxidizer gas OOG: Oxidizer off gas PW: Pure water RFG: Raw fuel gas WA: Water

Claims (7)

A fuel cell stack comprising a plurality of power generation units each having a single cell including an electrolyte layer and an air electrode and a fuel electrode facing each other across the electrolyte layer, wherein the fuel facing the fuel electrode in each power generation unit. Gas in the fuel electrode side gas supply manifold that supplies gas to the chamber, the fuel electrode side gas discharge manifold that discharges gas from the fuel chamber in each power generation unit, and the air chamber facing the air electrode in each power generation unit. A fuel cell stack in which an air pole side gas supply manifold for supplying fuel and an air pole side gas discharge manifold for discharging gas from the air chamber in each power generation unit are formed.
A combustor that burns gas and
A fuel pole side gas discharge flow path connecting the fuel pole side gas discharge manifold and the combustor of the fuel cell stack,
An air pole side gas discharge flow path connecting the air pole side gas discharge manifold and the combustor of the fuel cell stack,
In a fuel cell module equipped with
In the specific gas discharge flow path which is at least one of the fuel pole side gas discharge flow path and the air pole side gas discharge flow path,
A cooling mechanism that cools the gas in the specific gas discharge flow path,
A pressure control mechanism arranged on the downstream side of the cooling mechanism and adjusting the pressure of the gas in the specific gas discharge flow path,
Is provided,
A fuel cell module characterized by that. In the fuel cell module according to claim 1, further
The fuel electrode side gas supply flow path connected to the fuel electrode side gas supply manifold of the fuel cell stack, and
An air electrode side gas supply flow path connected to the air electrode side gas supply manifold of the fuel cell stack,
Air pole side gas including at least the air pole side gas supply flow path, the air pole side gas supply manifold, the air chamber of each power generation unit, the air pole side gas discharge manifold, and the air pole side gas discharge flow path. Includes a flow path, at least the fuel pole side gas supply flow path, the fuel pole side gas supply manifold, the fuel chamber of each power generation unit, the fuel pole side gas discharge manifold, and the fuel pole side gas discharge flow path. A gas flow path on the fuel electrode side, a pressure measuring unit for measuring the pressure of at least one of them, and a pressure measuring unit.
A control unit that controls the pressure control mechanism based on the pressure measurement result by the pressure measurement unit,
To prepare
A fuel cell module characterized by that. In the fuel cell module according to claim 1 or 2.
The cooling mechanism and the pressure control mechanism are provided at least in the fuel electrode side gas discharge flow path.
The fuel cell module further
A desulfurizer that desulfurizes raw fuel gas,
A branch flow path connecting a position downstream of the cooling mechanism in the fuel electrode side gas discharge flow path and the desulfurizer, and a branch flow path.
To prepare
A fuel cell module characterized by that. In the fuel cell module according to any one of claims 1 to 3.
The cooling mechanism includes at least one of a gas to be supplied to the air electrode side gas supply manifold, a gas to be supplied to the fuel electrode side gas supply manifold, and a gas in the specific gas discharge flow path. Including a heat exchange unit that exchanges heat between
A fuel cell module characterized by that. In the fuel cell module according to any one of claims 1 to 3, further
An evaporator that evaporates water and
A reformer that reforms raw fuel gas using the water evaporated in the evaporator, and
Equipped with
The cooling mechanism includes a heat exchange unit that exchanges heat between the water supplied to the evaporator and the gas in the specific gas discharge flow path.
A fuel cell module characterized by that. In the fuel cell module according to any one of claims 1 to 5.
In each power generation unit, a through hole is further formed, a portion surrounding the through hole is joined to the peripheral edge portion of the single cell, and an air chamber facing the air electrode and a fuel chamber facing the fuel electrode are formed. Has a first separator to partition,
A fuel cell module characterized by that. In the fuel cell module according to claim 6,
Each said power generation unit further
With a conductive interconnector electrically connected to the single cell,
A through hole is formed, and a portion surrounding the through hole is joined to the peripheral edge portion of the interconnector so that one of the air chamber and the fuel chamber and the air chamber and the fuel chamber in the other power generation unit are formed. A second separator that separates the other,
Have,
A fuel cell module characterized by that.

Images