JP2018049700A - Solid oxide fuel cell device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid exfoliation, breakdown or deterioration of a conductive member, even if thermal stress during power generation or stress due to variation in the mounting position of fuel battery cell acts, in a conductive member for taking out power from the fuel battery cell unit to the outside.SOLUTION: In a solid oxide fuel cell device, bus bars 200, 202 includes connecting parts 200A, 202A connected to the upper and lower ends of a fuel battery cell unit 16, and connections 200B, 202B to be connected with a current extraction terminal 206A. In the bus bars 200, 202, first stress relaxation parts 201A, 203A, provided in the connecting parts 200A, 202A and deforming upon receiving stress, and second stress relaxation parts 201B, 203B, provided between lower end side connecting parts 200A and the connection 200B, and deforming upon receiving stress, are formed.SELECTED DRAWING: Figure 10

Description

  The present invention relates to a solid oxide fuel cell device.

  A solid oxide fuel cell device (hereinafter also referred to as “SOFC”) uses an oxide ion conductive solid electrolyte as an electrolyte, has electrodes attached to both sides thereof, and supplies fuel gas to one side. The fuel cell operates at a relatively high temperature by supplying an oxidant gas (air, oxygen, etc.) to the other side. In such a solid oxide fuel cell device, the fuel cell is accommodated in a module container. For this reason, the electric power generated by the fuel cell is provided with a conductive current extraction terminal that penetrates the module container, and the current extraction terminal and the fuel cell are connected by a conductive member (bus bar). And taken out to the outside through a current extraction terminal.

  As a configuration for taking out electric power from the fuel cell in such a fuel cell device, for example, in Patent Document 1 (particularly, paragraph 0037 and FIG. 9), conductive members are provided at the upper and lower ends of the fuel cell unit. The structure which connects, connects an electroconductive member to the electric current extraction terminal provided in the module case, and takes out an electric current from the electric current extraction terminal via an electroconductive member is disclosed. Thus, by connecting the conductive member to both ends of the fuel cell unit, current can be collected efficiently. Furthermore, Patent Document 1 discloses that a stress relaxation portion is provided in a conductive member to avoid thermal stress relaxation and stress concentration.

JP 2012-79519 A

  Here, in recent years, downsizing of the fuel cell device is desired, and a conductive member that connects the fuel cell and the current extraction terminal is formed of a conductive thin plate. By forming the conductive member from a conductive thin plate, there are advantages of not only miniaturization but also cost reduction and weight reduction.

Both ends of the conductive member are connected to the fuel cell and the current extraction terminal, respectively. When exposed to high temperatures during power generation, the conductive member becomes conductive due to differences in temperature distribution and thermal expansion of the members constituting the fuel cell device. Thermal stress is generated at the upper and lower ends of the conductive member. In addition, when the fuel cell device is assembled, stress may be generated at the lower end portion of the conductive member on the current extraction terminal side due to variations in the mounting position of the fuel cell. Since the conductive member is connected to the fuel cell unit by gripping or bonding with a conductive adhesive, if the stress concentrates on the lower end of the conductive member, the conductive member peels off the fuel cell. There is a risk of disconnection or short circuit.
Further, if the conductive member is made into a thin plate shape as described above, the strength is lowered, and therefore there is a possibility that the conductive member is deteriorated or damaged due to the influence of the stress. In addition, although patent document 1 discloses disposing a stress relaxation portion on the output terminal, it does not disclose a specific configuration of the stress relaxation portion.

  The present invention has been made in view of the above problems, and in a conductive member for taking out electric power from the fuel cell unit to the outside, the stress generated due to thermal stress during power generation or variations in the mounting position of the fuel cell. The purpose is to prevent peeling of the conductive member and breakage or deterioration of the conductive member even if acts.

  A solid oxide fuel cell device according to the present invention includes a plurality of electrically connected columnar fuel cells that perform a power generation reaction with a fuel gas and an oxidant gas, and a module that houses the plurality of fuel cells. A container, a plate-like conductive member electrically connected to the fuel cell, and fixed to one end and the other end of the fuel cell; and the power generated by the fuel cell that is fixed to the module container. And a conductive member including a connecting portion connected to one end and the other end of the fuel cell, and a connecting portion connected to the current extraction portion, and a conductive member. The stress member is provided at the connection portion and deforms when subjected to stress, and the second stress relaxation portion provided between the connection portion and the connection portion on one end side and deforms when subjected to stress. And is formed .

  According to the present invention configured as described above, the first stress relaxation portion is provided in the connecting portion of the conductive member, and the second stress relaxation portion is provided between the connecting portion and the connection portion. As a result, the stress due to the thermal expansion of the fuel cell is relaxed by the deformation of the first stress relaxation portion, and the stress generated on the current extraction portion side of the conductive member due to the variation in the mounting position of the fuel cell is the second stress. It can be relaxed by the relaxation part. For this reason, it can prevent that a conductive member peels from a fuel battery cell, and can prevent that a conductive member breaks and deteriorates.

In this invention, Preferably, an electroconductive member consists of one member and a 2nd stress relaxation part has a bending point.
According to the present invention having the above-described configuration, the conductive member can be provided with a function of relaxing stress only by providing a bending point by bending the plate-like conductive member, which is a simple process. Further, since the second stress relaxation portion is easily deformed with respect to the stress at the bending point, the stress concentration generated in the current extraction portion side portion of the conductive member is relaxed, and a short circuit due to peeling of the conductive member or the conductive member Can be further prevented from being damaged or deteriorated.

  In the present invention, preferably, the second stress relaxation portion includes two bending points, the one bending point bends toward one surface side of the conductive member, and the other bending point faces the other surface side of the conductive member. Bending towards.

  When a force is applied to the conductive member from the connection portion and the second stress relaxation portion is deformed, the stress applied to the current extraction portion side portion of the conductive member can be relaxed. May cause a short circuit. On the other hand, according to the present invention having the above configuration, the shape in the vicinity of the stress relaxation portion is substantially Z-shaped. As a result, even if a displacement occurs between the connecting portion and the connecting portion, the second stress relaxation portion is deformed without spreading greatly around, so that the second stress relaxation portion comes into contact with the surrounding members to cause a short circuit. It can be prevented from occurring.

In the present invention, preferably, the bending point of the second stress relaxation portion is a curved shape.
According to the present invention having the above configuration, it is possible to prevent stress from being excessively concentrated on the bending point of the second stress relaxation portion. Thereby, deterioration and breakage of the second stress relaxation portion can be suppressed, stress relaxation performance can be maintained, stress concentration generated in the current extraction portion side portion of the conductive member is relaxed, and the conductive member is peeled off Short circuit and damage and deterioration of the conductive member can be further suppressed. Furthermore, when the surface of the conductive member is coated with a conductive film such as silver, it is possible to prevent the film from tearing.

  In the present invention, preferably, the current extraction part is arranged at the lower part of the module container, one end of the fuel cell is located at the lower part of the module container, and an off-gas combustion part is provided at the other end side of the fuel cell. .

  According to the present invention having the above-described configuration, the current extraction part and one end of the fuel battery cell are arranged at the lower part of the module container having a low temperature and a small influence of thermal expansion compared to the upper part of the fuel battery cell provided with the combustion part. Therefore, it is possible to further suppress the generation of stress generated in the current extraction portion side portion of the conductive member.

In this invention, Preferably, a 1st stress relaxation part has the protrusion which protrudes toward the side of either surface.
According to the present invention having the above-described configuration, since the first stress relaxation portion has the protrusion protruding toward one of the surfaces, the stress due to thermal expansion can be relaxed in this protrusion, and thus the conductive The stress generated in the member can be suppressed, the conductive member can be prevented from peeling off from the fuel cell, and the conductive member can be prevented from being damaged or deteriorated.

In the present invention, preferably, the first stress relaxation portion is flat and the protrusions are provided at two or more locations.
Since the first stress relaxation portion is adjacent to the columnar fuel cell, if a large stress deformation occurs, there is a risk that the fuel cell will come into contact with the fuel cell. On the other hand, according to the present invention having the above-described configuration, stress can be relieved by a plurality of protrusions, and other portions are formed flat, so that stress deformation can be minimized. The occurrence of a short circuit can be prevented.

  According to the present invention, a conductive member for taking out electric power from the fuel cell unit to the outside even if thermal stress during power generation or stress caused by variation in the mounting position of the fuel cell acts. It is possible to prevent peeling of the conductive member and damage or deterioration of the conductive member.

1 is an overall configuration diagram showing a solid oxide fuel cell apparatus (SOFC) according to an embodiment of the present invention. FIG. 2 is a side sectional view showing a fuel cell module of a solid oxide fuel cell device according to an embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. It is a disassembled perspective view of a module case and an air passage cover. It is a perspective view which shows the inner surface of the closing side plate which comprises a module case. (A) is a perspective view which shows the 1st member which comprises a scattering suppression cover, (B) is a perspective view which shows the 2nd member which comprises a scattering suppression cover, (C) is 1st and 1st It is a perspective view which shows a mode that 2 members are attached. It is a vertical expanded sectional view of the apparatus longitudinal direction of the pipe joint vicinity in the state which attached the scattering suppression cover. It is a perspective view which shows the periphery of the scattering suppression cover in an assembly state. It is a fragmentary sectional view showing a fuel cell unit of a solid oxide fuel cell device by one embodiment of the present invention. It is a perspective view which shows the mechanism for taking out electric power from the fuel cell assembly in the solid oxide fuel cell apparatus of one Embodiment of this invention to the exterior. It is sectional drawing which shows the mechanism for taking out electric power from the fuel cell assembly in the solid oxide fuel cell apparatus of one Embodiment of this invention to the exterior, and is sectional drawing in the position of the bus-bar connected to the inner side electrode terminal. is there. It is sectional drawing which shows the mechanism for taking out electric power from the fuel cell assembly in the solid oxide fuel cell apparatus of one Embodiment of this invention to the exterior, and is sectional drawing in the position of the bus-bar connected to the outer side electrode layer. is there. It is a perspective view which shows the structure of the bus bar used for the solid oxide fuel cell apparatus of one Embodiment of this invention. It is a vertical sectional view showing the configuration of the current extraction terminal unit. FIG. 3 is a side sectional view showing a fuel cell module of a solid oxide fuel cell device according to an embodiment of the present invention, similar to FIG. 2. FIG. 4 is a cross-sectional view along the line III-III in FIG. 2, similar to FIG. 3. It is a figure which shows the electric field produced between the electric current extraction terminal connected to the + pole, and the bottom plate of a module container. The bus bar attached to the fuel cell unit located in the edge part of the-side of a fuel cell assembly is shown.

Next, a solid oxide fuel cell device according to an embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is an overall configuration diagram showing a solid oxide fuel cell apparatus (SOFC) according to an embodiment of the present invention. As shown in FIG. 1, a solid oxide fuel cell apparatus (SOFC) 1 according to an embodiment of the present invention includes a fuel cell module 2 and an auxiliary unit 4.

  The fuel cell module 2 includes a housing 6, and a metal module case 8 is built in the housing 6 via a heat insulating material 7. In the power generation chamber 10, which is the lower part of the module case 8, which is a sealed space, a fuel cell that performs a power generation reaction with fuel gas and oxidant gas (hereinafter referred to as “power generation air” or “air” as appropriate). A cell assembly 12 is accommodated. The fuel cell assembly 12 includes a plurality of fuel cell units 16 (see FIG. 6) connected in series. In this example, the fuel cell assembly 12 has 128 fuel cell units 16.

  A combustion chamber 18 as a combustion section is formed above the power generation chamber 10 of the module case 8 of the fuel cell module 2. In this combustion chamber 18, the remainder that was not used for the power generation reaction (which did not contribute to power generation) The fuel gas and the remaining air are combusted to generate exhaust gas (in other words, combustion gas). Further, the module case 8 is covered with the heat insulating material 7 to suppress the heat inside the fuel cell module 2 from being diffused to the outside air. Further, a reformer 120 for reforming the fuel gas is disposed above the combustion chamber 18, and the reformer 120 is heated to a temperature at which a reforming reaction can be performed by the combustion heat of the residual gas. Yes.

  Further, an evaporator 140 is provided in the heat insulating material 7 above the module case 8 in the housing 6. The evaporator 140 performs heat exchange between the supplied water and the exhaust gas, thereby evaporating the water to generate water vapor, and a mixed gas (hereinafter referred to as “fuel gas”) of the water vapor and the raw fuel gas. Is supplied to the reformer 120 in the module case 8.

  Next, the auxiliary unit 4 stores pure water tank 26 that stores water condensed from moisture contained in the exhaust from the fuel cell module 2 and makes it pure water with a filter, and water supplied from the water storage tank. Is provided with a water flow rate adjusting unit 28 (such as a “water pump” driven by a motor). The auxiliary unit 4 includes a gas shutoff valve 32 that shuts off the fuel supplied from the fuel supply source 30 that is a reduction in the supply of raw material gas such as city gas, and a desulfurizer 36 that removes sulfur from the fuel gas. A fuel flow rate adjusting unit 38 (such as a “fuel pump” driven by a motor) for adjusting the flow rate of the fuel gas, and a valve 39 for shutting off the fuel gas flowing out from the fuel flow rate adjusting unit 38 when the power is lost. Yes. Further, the auxiliary unit 4 includes an electromagnetic valve 42 that shuts off the air supplied from the air supply source 40, a reforming air flow rate adjusting unit 44 that adjusts the air flow rate, and a power generation air flow rate adjusting unit 45 (with a motor). Driven "air blower", etc., a first heater 46 for heating the reforming air supplied to the reformer 120, and a second heater 48 for heating the power generating air supplied to the power generation chamber. I have. The first heater 46 and the second heater 48 are provided in order to efficiently raise the temperature at startup, but may be omitted.

  In this embodiment, the partial oxidation reforming reaction (POX) and the steam reforming reaction (SR) are performed from the POX process in which only the partial oxidation reforming reaction (POX) occurs in the reformer 120 when the apparatus is started. The SR process in which only the steam reforming reaction is performed may be performed through the ATR process in which the mixed autothermal reforming reaction (ATR) occurs, or the POX process may be omitted and the ATR process may be changed to the SR process. You may comprise so that it may transfer, and it may comprise so that a POX process and an ATR process may be abbreviate | omitted and only an SR process may be performed. In the configuration in which only the SR step is performed, the reforming air flow rate adjustment unit 44 is unnecessary.

  Next, a hot water production apparatus 50 to which exhaust gas is supplied is connected to the fuel cell module 2. The hot water production apparatus 50 is supplied with tap water from the water supply source 24, and the tap water is heated by the heat of the exhaust gas and supplied to a hot water storage tank of an external hot water heater (not shown). The fuel cell module 2 is provided with a control box 52 for controlling the amount of fuel gas supplied and the like. Furthermore, the fuel cell module 2 is connected to an inverter 54 that is a power extraction unit (power conversion unit) for supplying the power generated by the fuel cell module to the outside.

  Next, the structure of the fuel cell module of the solid oxide fuel cell device according to an embodiment of the present invention will be described with reference to FIGS. 2 is a side sectional view showing a fuel cell module of a solid oxide fuel cell device according to an embodiment of the present invention, and FIG. 3 is a sectional view taken along line III-III in FIG. 4 is an exploded perspective view of the module case and the air passage cover.

  As shown in FIGS. 2 and 3, the fuel cell module 2 includes a fuel cell assembly 12 and a reformer 120 provided inside a module case 8 covered with a heat insulating material 7, and the module case 8. And an evaporator 140 provided in the heat insulating material 7.

  First, as shown in FIG. 4, the module case 8 includes a substantially rectangular top plate 8a, bottom plate 8c, and a pair of opposing side plates 8b that connect the sides extending in the longitudinal direction (left-right direction in FIG. 2). A cylindrical body and a closed side plate that closes two opposing openings at both ends in the longitudinal direction of the cylindrical body and connects the sides extending in the width direction of the top plate 8a and the bottom plate 8c (left and right direction in FIG. 3) 8d and 8e.

  The module case 8 has a top plate 8 a and side plates 8 b covered with an air passage cover 160. The air passage cover 160 includes a top plate 160a and a pair of opposing side plates 160b. An opening 167 for passing through the exhaust pipe 171 and an opening 160c for connecting the power generation air introduction pipe 74 are provided at a substantially central portion of the top plate 160a. The top plate 160a and the top plate 8a and the side plate 160b and the side plate 8b are separated by a predetermined distance. Thereby, between the outside of the module case 8 and the heat insulating material 7, specifically, between the top plate 8a and the side plate 8b of the module case 8, and between the top plate 160a and the side plate 160b of the air passage cover 160, Air passages 161a and 161b as oxidant gas supply passages are formed along the outer surfaces of the plate 160a and the side plates 160b (see FIG. 3).

  At the lower part of the side plate 8b of the module case 8, a plurality of through holes 8f are provided (see FIG. 4). The power generation air is supplied into the air passage 161a from a power generation air introduction pipe 74 provided at a substantially central portion on the closed side plate 8e side of the module case 8 in the top plate 160a of the air passage cover 160 (FIG. 2). reference). Then, the power generation air is injected into the power generation chamber 10 through the air passages 161a and 161b from the outlet 8f toward the fuel cell assembly 12 (see FIGS. 3 and 4).

  FIG. 5 is a perspective view showing the inner surface of the closing side plate 8 d constituting the module case 8. As shown in the figure, a first protrusion 180A and a second protrusion 180B are formed on the inner surface of the closing side plate 8d so as to extend in the vertical direction along the edges on both sides in the width direction. The first protrusion 180A and the second protrusion 180B each have a rectangular horizontal cross-sectional shape. The inner surfaces of the first projecting portion 180A and the second projecting portion 180B constitute projecting surfaces that project to the fuel cell side. A recess (groove) 180C having a rectangular cross section is formed between the first protrusion 180A and the second protrusion 180B. A rectangular notch 180A1 is formed on the side of the module case 8 on the side plate 8b side below the surface of the first protrusion 180A facing the fuel cell assembly 12. Further, a rectangular notch 180B1 is formed on the side of the module case 8 on the side plate 8b side below the surface of the second protrusion 180B facing the fuel cell assembly 12.

  In addition, the air passages 161a and 161b have heat exchange promoting members that promote heat exchange between the exhaust gas in the first and second exhaust passages 172a and 172b and the air in the air passages 161a and 161b. Plate fins 162 and 163 are provided (see FIG. 3). The plate fins 162 are provided in the horizontal direction so as to extend in the longitudinal direction and the width direction between the top plate 8 a of the module case 8 and the top plate 160 a of the air passage cover 160. That is, the plate fin 162 is provided in a portion corresponding to a later-described first exhaust passage 172a in the air passage 161a. Further, the plate fin 163 extends between the side plate 8b of the module case 8 and the side plate 160b of the air passage cover 160 and extends above the fuel cell unit 16 in the longitudinal direction and the vertical direction. Is provided. That is, the plate fins 163 are provided in portions corresponding to a second exhaust passage 172b and an exhaust concentration portion 176, which will be described later, in the air passage 161b.

  The power generation air flowing through the air passages 161a and 161b is inside the module case 8 inside the plate fins 162 and 163 (specifically along the top plate 8a and the side plate 8b), particularly when passing through the plate fins 162 and 163. Heat exchange is performed with the exhaust gas passing through the exhaust passage). For this reason, the portions where the plate fins 162 and 163 are provided in the air passages 161a and 161b function as a heat exchanger (heat exchange section). The portion provided with the plate fins 162 constitutes a main heat exchanger portion, and the portion provided with the plate fins 163 constitutes a subordinate heat exchanger portion.

  Next, the evaporator 140 is fixed on the top plate 8a of the module case 8 so as to extend in the horizontal direction. Further, a portion 7a of the heat insulating material 7 is disposed between the evaporator 140 and the module case 8 so as to fill these gaps (see FIGS. 2 and 3).

  Specifically, the evaporator 140 includes a fuel supply pipe 63 that supplies water and raw fuel gas (which may include reforming air) to one side end side in the longitudinal direction (left-right direction in FIG. 2). The exhaust gas exhaust pipe 82 (see FIG. 3) for exhaust gas exhaust is connected, and the upper end of the exhaust pipe 171 is connected to the other side end in the longitudinal direction. The exhaust pipe 171 extends downward through an opening 167 formed in the top plate 160 a of the air passage cover 160, and is connected to an exhaust port 111 formed on the top plate 8 a of the module case 8. The exhaust port 111 is an opening through which the exhaust gas generated in the combustion chamber 18 in the module case 8 is discharged to the outside of the module case 8, and is substantially at the center of the top plate 8 a that is substantially rectangular in top view. Is formed.

  In addition, as shown in FIGS. 2 and 3, the evaporator 140 has an evaporator case 141 that is substantially rectangular in top view. The evaporator case 141 is formed by joining two low-profile bottomed rectangular cylindrical upper case 142 and lower case 143 with an intermediate plate 144 sandwiched therebetween.

  Accordingly, the evaporator case 141 has a two-layer structure in the vertical direction, and an exhaust passage portion 140A through which the exhaust gas supplied from the exhaust pipe 171 passes is formed in the lower layer portion, and a fuel layer is formed in the upper layer portion. An evaporation unit 140B that evaporates water supplied from the supply pipe 63 to generate water vapor, and a mixing unit 140C that mixes the water vapor generated in the evaporation unit 140B and the raw fuel gas supplied from the fuel supply pipe 63 are provided. It has been.

  The evaporator 140B and the mixer 140C are formed in a space where the evaporator 140 is partitioned by a partition plate provided with a plurality of communication holes (slits). The evaporation unit 140B is filled with alumina balls (not shown).

  Similarly, the exhaust passage portion 140A is partitioned into three spaces from the upstream side to the downstream side of the exhaust gas by two partition plates having a plurality of communication holes. The second space is filled with a combustion catalyst (not shown). That is, the evaporator 140 of the present embodiment includes a combustion catalyst device.

  In such an evaporator 140, heat exchange is performed between the water in the evaporation section 140B and the exhaust gas passing through the exhaust passage section 140A, and the water in the evaporation section 140B is evaporated by the heat of the exhaust gas, Water vapor will be generated. Further, heat exchange is performed between the mixed gas in the mixing section 140C and the exhaust gas passing through the exhaust passage section 140A, and the temperature of the mixed gas is raised by the heat of the exhaust gas.

  Further, as shown in FIG. 2, a mixed gas supply pipe 112 for supplying a mixed gas to the reformer 120 is connected to the mixing unit 140C. The mixed gas supply pipe 112 is disposed so as to pass through the inside of the exhaust pipe 171, one end is connected to an opening 144 a formed in the intermediate plate 144, and the other end is formed on the top surface of the reformer 120. Connected to the mixed gas supply port 120a. The mixed gas supply pipe 112 passes through the exhaust passage portion 140A and the exhaust pipe 171 and extends vertically downward into the module case 8, where it is bent approximately 90 ° and extends horizontally along the top plate 8a. , Bent downward by approximately 90 ° and connected to the reformer 120.

  Next, the reformer 120 is disposed so as to extend horizontally along the longitudinal direction of the module case 8 above the combustion chamber 18, and the exhaust gas guiding member 130 is disposed between the top plate 8 a of the module case 8. And fixed to the top plate 8a with a predetermined distance therebetween. The reformer 120 has a substantially rectangular outer shape in a top view, but is an annular structure in which a through hole 120b is formed in the center, and has a casing in which an upper case 121 and a lower case 122 are joined. ing. The through hole 120b is positioned so as to overlap the exhaust port 111 formed in the top plate 8a in a top view, and preferably, the exhaust port 111 is formed at the center position of the through hole 120b.

  On one end side in the longitudinal direction of the reformer 120 (closed side plate 8e side of the module case 8), the mixed gas supply pipe 112 is connected to the mixed gas supply port 120a provided in the upper case 121, and the other end side ( On the closed side plate 8 d side), the fuel gas supply pipe 64 is connected to the lower case 122, and the hydrogen desulfurizer hydrogen extraction pipe 65 extending to the desulfurizer 36 is connected to the upper case 121. Therefore, the reformer 120 receives the mixed gas (that is, raw fuel gas mixed with water vapor (may include reforming air)) from the mixed gas supply pipe 112, reforms the mixed gas therein, The reformed gas (that is, fuel gas) is discharged from the fuel gas supply pipe 64 and the hydrogen extraction pipe 65 for hydrodesulfurizer.

  The reformer 120 is divided into three spaces by the two partition plates 123a and 123b, so that the reformer 120 receives a mixed gas from the mixed gas supply pipe 112 in the reformer 120. And a reforming section 120B filled with a reforming catalyst (not shown) for reforming the mixed gas, and a gas discharge section 120C for discharging the gas that has passed through the reforming section 120B are formed. (See FIG. 2). The reforming unit 120B is a space sandwiched between the partition plates 123a and 123b, and the reforming catalyst is held in this space. The mixed gas and the reformed fuel gas are movable through a plurality of communication holes (slits) provided in the partition plates 123a and 123b. As the reforming catalyst, a catalyst obtained by imparting nickel to the alumina sphere surface or a catalyst obtained by imparting ruthenium to the alumina sphere surface is appropriately used.

  The mixed gas supplied from the evaporator 140 through the mixed gas supply pipe 112 is ejected to the mixed gas receiving unit 120A through the mixed gas supply port 120a. The mixed gas is expanded in the mixed gas receiving unit 120A, the jetting speed is reduced, and is supplied to the reforming unit 120B through the partition plate 123a.

In the reforming unit 120B, the mixed gas moving at a low speed is reformed into a fuel gas by the reforming catalyst, and the fuel gas passes through the partition plate 123b and is supplied to the gas discharge unit 120C.
In the gas discharge unit 120C, the fuel gas is discharged to the fuel gas supply pipe 64 and the hydrogen extraction pipe 65 for the hydrodesulfurizer.

  A fuel gas supply pipe 64 as a fuel gas supply passage extends downward in the module case 8 along the closed side plate 8d, is bent approximately 90 ° in the vicinity of the bottom plate 8c, and extends in the horizontal direction. It extends into the manifold 66 formed below the inner side, and further extends horizontally in the manifold 66 to the vicinity of the closed side plate 8e on the opposite side. The fuel gas supply pipe 64 is divided into an inflow side pipe 64A connected to the manifold 66 and an outflow side pipe 64B connected to the reformer 120, and these inflow side pipe 64A and outflow side pipe 64B. Are connected by a pipe joint 64C. The pipe joint 64 </ b> C is formed of a material having lower heat resistance than the material constituting the inflow side pipe 64 </ b> A, the outflow side pipe 64 </ b> B, and the module case 8. The pipe joint 64 </ b> C is located obliquely above the fuel cell assembly 12.

  A plurality of fuel supply holes 64 b are formed in the lower surface of the horizontal portion 64 a of the fuel gas supply pipe 64, and fuel gas is supplied into the manifold 66 from the fuel supply holes 64 b. A lower support plate 68 having a through hole for supporting the fuel cell unit 16 is attached above the manifold 66, and the fuel gas in the manifold 66 is supplied into the fuel cell unit 16. The An ignition device 83 for starting combustion of fuel gas and air is provided in the combustion chamber 18.

  Further, the pipe joint 64C that connects the inflow side pipe 64A and the outflow side pipe 64B is surrounded by the scattering suppression cover 190. FIG. 6A is a perspective view showing a first member constituting the scattering suppression cover, FIG. 6B is a perspective view showing a second member constituting the scattering suppression cover, and FIG. It is a perspective view which shows a mode that a 2nd member is attached. FIG. 7 is a vertically enlarged cross-sectional view in the longitudinal direction of the apparatus in the vicinity of the pipe joint in a state where the scattering suppression cover is attached.

  As shown in FIG. 6A, the first member 191 has a rectangular parallelepiped shape such that one surface is open. Specifically, the first member 191 includes a lateral surface 191C, a front and rear surface 191D extending from front and rear edges of the lateral surface 191C, an upper surface 191A extending from an upper edge of the lateral surface 191C, and a lower surface of the lateral surface 191C. And a lower surface 191B extending from the edge. The upper and lower surfaces 191A and 191B are respectively formed with recesses 191F extending from the opening side. Further, a rectangular through hole 191E extending in the vertical direction is formed in the front and rear surface 191D.

As shown in FIG. 6B, the second member 192 has a rectangular parallelepiped shape such that one surface is open. Specifically, the second member 192 includes a lateral surface 192C, a front and back surface 192D extending from the front and rear edges of the lateral surface 192C, an upper surface 192A extending from an upper edge of the lateral surface 192C, and a lower surface of the lateral surface 192C. And a lower surface 192B extending from the edge. The upper and lower surfaces 192A and 192B are respectively formed with recesses 192F extending from the opening side. Further, a rectangular protrusion 192E extending in the vertical direction is formed on the front and rear surface 191D. In the protrusion 192E, the side on the opening side of the second member 192 is connected to the front and back surface 192D, and a gap is formed between the other side and the front and back surface 192D. The protruding portion 192E normally protrudes outward from the front and rear surface 192D, but can be bent until it is positioned inside the front and rear surface 192D. Further, the corners between the front and rear surfaces 192D and the upper and lower surfaces 192A and 192B are not connected, and a slit 192G is formed.
Here, the recesses 191F and 192F of the first member 191 and the second member 192 are preferably bent toward the inside of the case. Thereby, it can prevent that peeling powder falls from the clearance gap between the fuel gas supply pipe 64 and the recessed parts 191F and 192F.

  The first member 191 and the second member 192 are made of a material having higher heat resistance than the pipe joint 64C. More preferably, the module case 8 is made of the same material.

  As shown in FIG. 6C, when the scattering prevention cover 190 is attached, the opening side of the first member 191 and the second member 192 is disposed so as to face each other with the pipe joint 64C interposed therebetween. Then, the first member 191 and the second member 192 are brought close to each other so that the fuel gas supply pipe 64 enters the recesses 191F and 192F, respectively. At this time, the upper and lower surfaces 191 </ b> A and 191 </ b> B of the first member 191 enter the slit 192 </ b> G of the second member 192. When the first and second members 191 and 192 are brought close to each other until the edges of the upper and lower surfaces 191A and 191B of the first member 191 come into contact with the lateral surface 192C of the second member 192, the second member 192 The protruding portion 192E enters and fits into the through hole 191E of the first member 191. As described above, the scattering suppression cover 190 is configured by fitting the first and second members 191 and 192, and the upper surfaces 191A and 192A are in contact with the upper surface of the pipe joint 64C as shown in FIG. It is supported by touching. Further, in the state where the scattering suppression cover 190 is attached in this manner, the upper surfaces 191A and 192A and the lower surfaces 191B and 192B of the first and second members 191 and 192 overlap each other. A recovery space 194 is formed below the pipe joint 64 </ b> C in the scattering suppression cover 190.

  In the present embodiment, the through hole 191E of the first member 191 and the protrusion 192E of the second member 192 that are fitted to each other are formed on the front and rear surfaces 191D and 192D of the first and second members 191 and 192, respectively. However, the present invention is not limited to this, and the upper surfaces 191A and 192A may be provided. Moreover, in this embodiment, although the scattering suppression cover 190 is comprised by two members, you may comprise by three or more members.

  FIG. 8 is a perspective view showing the periphery of the scattering prevention cover in the assembled state. The closed side plate 8d is closed after the scattering suppression cover 190 is attached to the pipe joint 64C. And in the state which closed the closed side board 8d, the scattering suppression cover 190 is accommodated in the recessed part 180C of the closed side board 8d. The surface of the scattering suppression cover 190 on the side of the fuel cell unit 16 is located on the same plane as the protruding surface of the first protrusion 180A and the second protrusion 180B of the closing side plate 8d on the fuel cell unit 16 side. Yes.

  A fuel gas supply pipe 64 as a fuel gas supply passage extends downward in the module case 8 along the closed side plate 8d, is bent approximately 90 ° in the vicinity of the bottom plate 8c, and extends in the horizontal direction. It extends into the manifold 66 formed below the inner side, and further extends horizontally in the manifold 66 to the vicinity of the closed side plate 8e on the opposite side. A plurality of fuel supply holes 64 b are formed in the lower surface of the horizontal portion 64 a of the fuel gas supply pipe 64, and fuel gas is supplied into the manifold 66 from the fuel supply holes 64 b. A lower support plate 68 having a through hole for supporting the fuel cell unit 16 is attached above the manifold 66, and the fuel gas in the manifold 66 is supplied into the fuel cell unit 16. The An ignition device 83 for starting combustion of fuel gas and air is provided in the combustion chamber 18.

  The exhaust gas guiding member 130 is disposed between the reformer 120 and the top plate 8 a so as to extend in the horizontal direction along the longitudinal direction of the module case 8. The exhaust gas guiding member 130 includes a lower guiding plate 131 and an upper guiding plate 132 that are separated by a predetermined distance in the vertical direction, and connecting plates 133 and 134 to which both ends of the longitudinal direction are attached (FIG. 2). FIG. 3). The upper guide plate 132 is bent at both ends in the width direction downward and is connected to the lower guide plate 131. The connecting plates 133 and 134 have upper ends connected to the top plate 8a and lower ends connected to the reformer 120, thereby fixing the exhaust gas guiding member 130 and the reformer 120 to the top plate 8a. ing.

  The lower guide plate 131 is formed with a convex step portion 131a in which the central portion in the width direction (left-right direction in FIG. 3) protrudes downward. On the other hand, as with the lower guide plate 131, the upper guide plate 132 is formed with a recess 132a so that the central portion in the width direction becomes concave downward. The convex step portion 131a and the concave portion 132a extend in the longitudinal direction in parallel in the vertical direction. The mixed gas supply pipe 112 extends horizontally in the recess 132a in the module case 8 and then bends downward in the vicinity of the closed side plate 8e, penetrates the upper guide plate 132 and the lower guide plate 131, It is connected to the reformer 120.

  In the exhaust gas guiding member 130, a gas reservoir (gas heat insulating layer) 135, which is an internal space that functions as a heat insulating layer, is formed by the upper guide plate 132, the lower guide plate 131, and the connecting plates 133 and 134. The gas reservoir 135 is in fluid communication with the combustion chamber 18. That is, the upper guide plate 132, the lower guide plate 131, and the connecting plates 133 and 134 are connected so as to form a predetermined gap, and are not airtightly connected. While it is possible for exhaust gas to flow into the gas reservoir 135 from the combustion chamber 18 during operation, or to allow air to flow in from the outside when stopped, the movement of gas between the inside and outside of the gas reservoir 135 is generally performed. Is moderate.

  The upper guide plate 132 is disposed at a predetermined vertical distance from the top plate 8a. Between the upper surface of the upper guide plate 132 and the top plate 8a, the upper guide plate 132 is horizontally aligned along the longitudinal direction and the width direction. An extended first exhaust passage 172a is formed. The first exhaust passage 172a is juxtaposed with the air passage 161a with the top plate 8a of the module case 8 interposed therebetween, and the plate fins 162, 163 in the air passages 161a, 161b are connected to the first exhaust passage 172a. Similar plate fins 175a are arranged. The plate fins 175a are provided at substantially the same location as the plate fins 162 when viewed from above, and face each other in the vertical direction across the top plate 8a.

  The upper guide plate 132 is disposed at a predetermined horizontal distance from the side surface of the upper guide plate 132 and the side plate 8b, and is arranged in the longitudinal direction and the vertical direction between the side surface of the upper guide plate 132 and the side plate 8b. An extended second exhaust passage 172b is formed. The second exhaust passage 172b communicates with the first exhaust passage 172a at the top. Also in the second exhaust passage 172b, plate fins 175b similar to the plate fins 162 and 163 in the air passages 161a and 161b are arranged. The lower end of the plate fin 175b extends to the height of the lower guide plate 131.

  Of the air passages 161a, 161b and the first and second exhaust passages 172a, 172b, in the portions where the plate fins 162, 163, 175a, 175b are provided, the power generation air flowing through the air passages 161a, 161b and the first and second Efficient heat exchange is performed with the exhaust gas flowing through the second exhaust passages 172a and 172b, and the power generation air is heated by the heat of the exhaust gas.

  The reformer 120 is disposed at a predetermined horizontal distance from the side plate 8b of the module case 8, and the exhaust gas passes between the reformer 120 and the side plate 8b from below to above. A third exhaust passage 173 is formed.

  Further, the lower guide plate 131 is disposed at a predetermined vertical distance from the top surface of the upper case 121 of the reformer 120, and between the lower guide plate 131 and the upper case 121 and the reformer. The 120 through-hole 120b forms a fourth exhaust passage 174 through which the exhaust gas that has passed through the through-hole 120b from the bottom to the top passes. The fourth exhaust passage 174 merges with the third exhaust passage 173 above the reformer 120 and in the vicinity of the side plate 8b to form an exhaust concentration portion 176 where exhaust gas concentrates.

Next, the fuel cell unit 16 will be described with reference to FIG. FIG. 9 is a partial cross-sectional view showing a fuel cell unit of a solid oxide fuel cell device according to an embodiment of the present invention.
As shown in FIG. 9, the fuel cell unit 16 has a cylindrical shape and includes a fuel cell 84 and inner electrode terminals 86 that are caps respectively connected to both ends of the fuel cell 84.

  The fuel cell 84 is a tubular structure extending in the vertical direction, and includes a cylindrical inner electrode layer 90 that forms a fuel gas flow path 88 therein, a cylindrical outer electrode layer 92, an inner electrode layer 90, and an outer side. An electrolyte layer 94 is provided between the electrode layer 92 and the electrode layer 92. The inner electrode layer 90 is a fuel electrode through which fuel gas passes and becomes a (−) electrode, while the outer electrode layer 92 is an air electrode in contact with air and becomes a (+) electrode.

  Since the inner electrode terminal 86 attached to the upper end side and the lower end side of the fuel cell 84 has the same structure, the inner electrode terminal 86 attached to the upper end side will be specifically described here. The upper portion 90 a of the inner electrode layer 90 includes an outer peripheral surface 90 b and an upper end surface 90 c exposed to the electrolyte layer 94 and the outer electrode layer 92. The inner electrode terminal 86 is connected to the outer peripheral surface 90b of the inner electrode layer 90 through a conductive sealing material 96, and is further in direct contact with the upper end surface 90c of the inner electrode layer 90, thereby Electrically connected. At the center of the inner electrode terminal 86, a fuel gas channel capillary 98 that communicates with the fuel gas channel 88 of the inner electrode layer 90 is formed.

  The fuel gas passage narrow tube 98 is an elongated thin tube provided so as to extend in the axial direction of the fuel cell 84 from the center of the inner electrode terminal 86. Therefore, a predetermined pressure loss occurs in the flow of the fuel gas flowing from the manifold 66 (see FIG. 2) into the fuel gas passage 88 through the fuel gas passage narrow tube 98 of the lower inner electrode terminal 86. To do. Accordingly, the fuel gas flow passage narrow tube 98 of the lower inner electrode terminal 86 acts as an inflow side flow passage resistance portion, and the flow passage resistance is set to a predetermined value. Further, a predetermined pressure loss also occurs in the flow of the fuel gas flowing out from the fuel gas flow path 88 to the combustion chamber 18 (see FIG. 2) through the fuel gas flow path narrow tube 98 of the upper inner electrode terminal 86. Therefore, the fuel gas flow passage narrow tube 98 of the upper inner electrode terminal 86 acts as an outflow side flow passage resistance portion, and the flow passage resistance is set to a predetermined value.

  The inner electrode layer 90 includes, for example, a mixture of Ni and zirconia doped with at least one selected from rare earth elements such as Ca, Y, and Sc, and Ni and ceria doped with at least one selected from rare earth elements. The mixture is formed of at least one of Ni and a mixture of lanthanum garade doped with at least one selected from Sr, Mg, Co, Fe, and Cu.

  The electrolyte layer 94 is, for example, zirconia doped with at least one selected from rare earth elements such as Y and Sc, ceria doped with at least one selected from rare earth elements, lanthanum gallate doped with at least one selected from Sr and Mg, Formed from at least one of the following.

  The outer electrode layer 92 includes, for example, lanthanum manganite doped with at least one selected from Sr and Ca, lanthanum ferrite doped with at least one selected from Sr, Co, Ni and Cu, Sr, Fe, Ni and Cu. It is formed from at least one of lanthanum cobaltite doped with at least one selected from the group consisting of silver and silver.

  Next, with reference to FIG. 10, FIG. 11A, and FIG. 11B, a mechanism for taking out electric power from the fuel cell assembly 12 and the fuel cell assembly to the outside will be described. FIG. 10 is a perspective view showing a mechanism for taking out electric power from the fuel cell assembly in the solid oxide fuel cell device according to the embodiment of the present invention, in which the module case is omitted. ing. 11A and 11B are cross-sectional views showing a mechanism for taking out electric power from the fuel cell assembly in the solid oxide fuel cell device according to one embodiment of the present invention. FIG. FIG. 11B is a cross-sectional view at the position of the bus bar connected to the terminal, and FIG. 11B is a cross-sectional view at the position of the bus bar connected to the outer electrode layer. In FIG. 10, the module case is omitted.

  In the fuel cell assembly 12, the inner electrode terminal 86 attached to the inner electrode layer 90 that is the fuel electrode of each fuel cell unit 16 has the outer electrode layer 92 that is the air electrode of the other fuel cell unit 16. All the fuel cell units 16 are connected in series by being electrically connected to the outer peripheral surface via the current collector 102.

  On the entire outer surface of the outer electrode layer 92 (air electrode) of each fuel cell unit 16, a silver thin film is formed as an electrode on the air electrode side. As shown in FIG. 10, FIG. 11A, and FIG. 11B, the most negative electrode side fuel cell unit 16 and the most positive electrode side fuel cell unit 16 of the fuel cell assemblies 12 connected in series. Bus bars 200 and 202 are respectively attached to the bus bar. A pair of openings are formed in the bottom plate 8c of the module case 8, and a pair of current extraction terminal units 204 are fixed to these openings. Each bus bar 200, 202 is connected to a current extraction terminal 206 </ b> A located inside the module case 8 of the current extraction terminal unit 204. Thereby, the electric power generated by the fuel cell assembly 12 can be taken out from the current extraction terminal 206B located outside the module case 8 of the pair of current extraction terminal units 204.

  FIG. 12 is a perspective view showing a configuration of a bus bar used in the solid oxide fuel cell device according to the embodiment of the present invention. In FIG. 12, the bus bar 200 attached to the fuel cell unit 16 located at the − side end of the fuel cell assembly 12 is shown. The bus bar 200 is provided between the connecting portion 200A connected to the fuel cell unit 16, the connecting portion 200B connected to the current extracting terminal 206A of the current extracting terminal unit 204, and the connecting portion 200A and the connecting portion 200B. 200C of connection parts. The bus bar 200 is made of a single plate-like member, and is formed by applying a silver coating to a metal material such as stainless steel.

  The connecting part 200A has a pair of attachment parts 200A2 for fixing to the fuel cell unit 16 at both upper and lower ends, and the pair of attachment parts 200A2 are connected by a curved part 200A1 having a curved shape extending in the vertical direction. . The curved portion 200A1 has a plate shape and is gently curved over the entire length so as to protrude toward the surface opposite to the fuel cell unit 16. The curved portion 200A1 may be curved so as to protrude toward the surface on the fuel cell unit 16 side. However, if the curved portion 200A1 comes into contact with the fuel cell unit 16, it causes a short circuit. It is preferable to curve so as to protrude toward the surface opposite to the unit 16. As shown in FIGS. 10, 11 </ b> A, and 11 </ b> B, the attachment portion 200 </ b> A <b> 2 is attached to the inner electrode terminals 86 at both the upper and lower ends of the fuel cell unit 16 on the most negative side of the fuel cell assembly 12.

  The connecting portion 200C includes bending points 200C1 and 200C2 at both ends. The bending point 200C1 is continuous with the lower end of the connecting portion 200A. At the bending point 200C1, the bus bar 200 is bent toward one surface (the surface opposite to the fuel cell assembly 12). Further, the bending point 200C2 is continuous with the upper end of the connecting portion 200B, and at the bending point 200C2, the bus bar 200 is bent toward the other surface (the surface on the fuel cell assembly 12 side). . These bending points 200C1 and 200C2 are not bent shapes but curved shapes having a curvature. In addition, the angles of the bending points 200C1 and 200C2 are desirably 90 degrees or more. Since the connecting portion 200C has two bending points 200C1 and 200C2, the vicinity of the connecting portion 200C of the bus bar 200 has a substantially Z-shape.

  The connecting portion 200B has a flat plate shape and has an opening 200B1. The opening 200 </ b> B <b> 1 formed in the connection part 200 </ b> B has substantially the same diameter as the opening 206 </ b> A <b> 1 of one current extraction terminal 206 </ b> A of the current extraction terminal unit 204. In a state where the opening 200B1 of the connection portion 200B and the opening 206A1 of the current extraction terminal 206A are overlapped, a bolt is inserted into the opening 200B1 of the connection portion 200B and the opening 206A1 of the current extraction terminal 206A, and tightened with a nut. Connection portion 200B is connected to current extraction terminal 206A.

Further, the bus bar 200 is formed with a first stress relaxation portion 201A that deforms when subjected to stress and a second stress relaxation portion 201B that deforms when subjected to stress. The first stress relaxation portion 201A includes a curved portion 200A1 of the connecting portion 200A. When thermal stress is generated due to the difference in thermal stress between the bus bar 200 and the fuel cell unit 16, the first stress relaxation portion 201A is deformed so that the curvature of the curved portion 200A1 changes.
The second stress relaxation part 201B includes two bending points 200C1 and 200C2 of the connecting part 200C. The second stress relaxation portion 201B deforms so that the angle between the two bending points 200C1 and 200C2 changes when there is a difference in the position between the members due to variation in the mounting position of the fuel cell assembly 12 or thermal expansion. .

Note that the bus bar 200 attached to the fuel cell unit 16 located at the − side end of the fuel cell assembly 12 has been described with reference to FIG. The bus bar 202 attached to the fuel cell unit 16 located at the end also differs only in the length of the connecting portion 202A and the attachment position to the fuel cell unit, and the other configurations are substantially the same. A pair of attachment portions 202A2 of the connecting portion 202A of the bus bar 202 are attached to the upper and lower end portions of the outer electrode layer 92, respectively. Further, the bus bar 202 is formed with a first stress relaxation portion 203A that deforms when subjected to stress, and a second stress relaxation portion 203B that deforms when subjected to stress. The first stress relieving portion 203A includes a curved portion 202A1 of the connecting portion 202A. The second stress relaxation portion 203B includes two bending points 202C1 and 202C2 of the connecting portion 202C.
As shown in FIGS. 11A and 11B, a pair of current extraction terminal units 204 are provided on both sides of the bottom plate 8 c of the module case 8. The current extraction terminal unit 204 is located below the combustion chamber 18.

  As described above, the notch 180A1 is formed in the lower portion of the first protrusion 180A formed on the closing side plate 8d of the module case 8. A first isolation space 193A is formed by the first protrusion 180A, the closed side plate 8d, and the bottom plate 8c. The first isolation space 193A communicates with the space in which the fuel cell assembly 12 is accommodated via the notch 180A1. The first protrusion 180A protrudes into the space inside the module case 8, and the space in which the fuel cell assembly 12 is accommodated in the module case 8 and the first isolation space 193A are only the notches 180A1. Therefore, the gas in the space in which the fuel cell assembly 12 in the module case 8 is accommodated is shielded by the first protrusion 180A, and the inflow of the first isolation space 193A is hindered. It is done. Thus, the first protrusion 180A functions as a shielding part that shields the inflow of gas into the first isolation space 193A. As shown in FIG. 11A, the current extraction terminal unit 204 connected to the bus bar 200 is arranged such that the current extraction terminal 206A is located in the first isolation space 193A.

  Further, as described above, the notch 180B1 is formed in the lower part of the second protrusion 180B formed on the closing side plate 8d of the module case 8. A second isolation space 193B is formed by the second protrusion 180B, the closed side plate 8d, and the bottom plate 8c. The second isolation space 193B communicates with the space in which the fuel cell assembly 12 is accommodated via the notch 180B1. The second protrusion 180B protrudes into the space in the module case 8, and the space in which the fuel cell assembly 12 is accommodated in the module case 8 and the second isolation space 193B are only the notches 180B1. Therefore, the gas in the space in which the fuel cell assembly 12 in the module case 8 is accommodated is shielded by the second protrusion 180B, preventing the second isolation space 193B from flowing in. It is done. Thus, the 2nd projection part 180B functions as a shielding part which shields inflow of gas to the 2nd isolation space 193B. As shown in FIG. 11B, the current extraction terminal unit 204 connected to the bus bar 202 is disposed such that the current extraction terminal 206A is located in the second isolation space 193B.

  FIG. 13 is a vertical sectional view showing the configuration of the current extraction terminal unit 204. As shown in the figure, the current extraction terminal unit 204 includes a terminal plate 206 extending in the vertical direction and an insulator 208 surrounding the terminal plate 206.

  The terminal board 206 is made of, for example, a metal member such as stainless steel, and the portion exposed to the outside is coated with silver. Bus bars 202 and 204 are connected to a current extraction terminal 206A at the upper end of the terminal board 206.

  The insulator 208 is made of, for example, an insulating material such as ceramics, and continues to the outer portion 208A located outside the module case 8, the enlarged diameter portion 208B continuous above the outer portion 208A, and the upper portion of the enlarged diameter portion 208B. An inner portion 208C. The outer portion 208A, the enlarged diameter portion 208B, and the inner portion 208C have a rectangular cross section. The width and depth of the outer portion 208A and the inner portion 208C are substantially equal, and the width and depth of the enlarged diameter portion 208B are larger than the width and depth of the outer portion 208A and inner portion 208C. The current extraction terminal unit 204 is fixed in a state where the enlarged diameter portion 208 </ b> B of the insulator 208 is in contact with the lower surface of the bottom plate 8 c of the module case 8.

  On the upper surface of the inner portion 208C of the insulator 208, a conduction suppression groove 208D is formed so as to surround the current extraction terminal 206A of the terminal plate 206. The conduction suppression groove 208D is formed in an annular shape so as to surround the terminal plate 206, and the outer shape of the cross section is substantially rectangular. The depth of the conduction suppression groove 208D is larger than the width of the conduction suppression groove 208D.

  As will be described later, the conduction suppressing groove 208D prevents the current extraction terminal 206A and the bottom plate 8c of the module case 8 from being short-circuited by a metal component containing silver covering the surface of the insulator 208 during power generation operation. Functions as a suppression unit. And this conduction | electrical_connection suppression part has a part (shortest part in the conduction | electrical_connection suppression groove part 208D) of the shortest path | route which connects the current extraction terminal 206A and the bottom board 8c of the module case 8 in the surface of the insulator 208, 206A and module case. The electric force lines running between the bottom plate 8c and the eighth base plate 8c do not follow the electric lines of force. Further, since the conduction suppressing groove 208D has a small width, it is difficult for silver scattered inside the module case 8 to enter, and the current extraction terminal 206A on the surface of the insulator 208 and the bottom plate 8c of the module case 8 are connected. Adherence of silver is suppressed in a portion of the path in the conduction suppressing groove 208D.

  Next, the flow of gas in the fuel cell module of the solid oxide fuel cell device according to one embodiment of the present invention will be described with reference to FIGS. 14 is a side sectional view showing a fuel cell module of a solid oxide fuel cell device according to an embodiment of the present invention, similar to FIG. 2, and FIG. 15 is similar to FIG. It is sectional drawing along the -III line. FIGS. 14 and 15 are diagrams in which arrows indicating gas flows are newly added in FIGS. 2 and 3, respectively, and show the state in which the heat insulating material 7 is removed for convenience of explanation. In the figure, solid line arrows indicate the flow of fuel gas, broken line arrows indicate the flow of power generation air, and alternate long and short dashed arrows indicate the flow of exhaust gas.

  As shown in FIG. 14, water and raw fuel gas (fuel gas) are fed into an evaporation section 140 </ b> B provided in the upper layer of the evaporator 140 from a fuel supply pipe 63 connected to one end side in the longitudinal direction of the evaporator 140. Supplied. The water supplied to the evaporation section 140B is heated by the exhaust gas flowing through the exhaust passage section 140A provided in the lower layer of the evaporator 140 to become water vapor. The water vapor and the raw fuel gas supplied from the fuel supply pipe 63 flow downstream in the evaporation unit 140B and are mixed in the mixing unit 140C. The mixed gas in the mixing section 140C is heated by the exhaust gas flowing through the lower exhaust passage section 140A.

  The mixed gas (fuel gas) formed in the mixing unit 140C is supplied to the reformer 120 in the module case 8 through the mixed gas supply pipe 112. Since the mixed gas supply pipe 112 passes through the exhaust passage portion 140A, the exhaust pipe 171, and the first exhaust passage 172a in this order, the mixed gas in the mixed gas supply pipe 112 is further increased by the exhaust gas flowing through these passages. Heated.

  The mixed gas flows into the mixed gas receiving part 120A in the reformer 120, and from here passes through the partition plate 123a and flows into the reforming part 120B. The mixed gas is reformed in the reforming unit 120B to become fuel gas. The fuel gas thus generated passes through the partition plate 123b and flows into the gas discharge part 120C.

  Further, the fuel gas branches from the gas discharge part 120C into the fuel gas supply pipe 64 and the hydrogen extraction pipe 65 for hydrodesulfurizer. The fuel gas that has flowed into the fuel gas supply pipe 64 is supplied into the manifold 66 from the fuel supply hole 64 b provided in the horizontal portion 64 a of the fuel gas supply pipe 64, and from the manifold 66 into each fuel cell unit 16. Supplied.

  As shown in FIGS. 14 and 15, the power generation air is supplied from the power generation air introduction pipe 74 to the air passage 161 a. When the power generation air passes through the plate fins 162 and 163 in the air passages 161 a and 161 b, the first and second exhaust passages 172 and 172 formed in the module case 8 below the plate fins 162 and 163. Efficient heat exchange is performed with the exhaust gas passing through 173, and the exhaust gas is heated.

  Thereafter, the power generation air is injected into the power generation chamber 10 from the plurality of air outlets 8 f provided at the lower portion of the side plate 8 b of the module case 8 toward the fuel cell assembly 12. Here, the first and second protrusions 180A and 180B are provided on the closing side plate 8d of the module case 8, and the fuel gas supply pipe 64 is disposed in the recess 180C between the first and second protrusions 180A and 180B. Has been. For this reason, the power generation air supplied into the power generation chamber 10 is sent uniformly without being disturbed by the fuel gas supply pipe 64. In the present embodiment, since the exhaust passage is not formed in the side portion of the fuel cell assembly 12, heat exchange between the power generation air and the exhaust gas is suppressed in this portion. Therefore, in the side part of the fuel cell assembly 12, the temperature unevenness in the vertical direction is less likely to occur in the power generation air in the air passage 161b.

  Further, as shown in FIG. 15, the fuel gas that has not been used for power generation in the power generation chamber 10 is burned in the combustion chamber 18 to become exhaust gas (combustion gas), and rises in the module case 8. Specifically, the exhaust gas is branched into a third exhaust passage 173 and a fourth exhaust passage 174, and between the outer surface of the reformer 120 and the side plate 8 b of the module case 8, and the reformer 120. The through-hole 120b passes between the reformer 120 and the exhaust gas guiding member 130. At this time, the exhaust gas passing through the fourth exhaust passage 174 is bisected in the width direction by the convex step portion 131a disposed above the through hole 120b of the reformer 120, and remains in the lower portion of the exhaust gas guiding member 130. Without being guided toward the third exhaust passage 173, the exhaust concentration portion 176 joins the exhaust gas flowing through the third exhaust passage 173. Here, since the plate fins 175b are provided in the second exhaust passage 172, the exhaust gas that has passed through the third exhaust passage 173 and the fourth exhaust passage 174 stays in the exhaust concentration portion 176 (see FIG. 15A). Part).

  Thereafter, the exhaust gas is introduced from the exhaust concentration portion 176 into the second exhaust passage 172b. Then, the exhaust gas that has passed through the second exhaust passage 172 b flows in the horizontal direction through the first exhaust passage 172 a and flows out from the exhaust port 111 formed at the center of the top plate 8 a of the module case 8.

  When the exhaust gas stays in the exhaust concentration portion 176, heat is generated between the power generation air and the exhaust gas via the plate fins 163 provided in the portion corresponding to the exhaust concentration portion 176 in the air passage 161b. Exchange is performed. Further, when the exhaust gas flows through the second exhaust passage 172b and the first exhaust passage 172a, the plate fins 175b and 175a provided in the second and first exhaust passages 172b and 172a, and the air passages 161a and 161b. Through the plate fins 162 and 163 provided at portions corresponding to the inner plate fins 175b and 175a, efficient heat exchange is performed between the power generation air and the exhaust gas. In this way, the temperature of the power generation air is raised by the heat of the exhaust gas.

  The exhaust gas flowing out from the exhaust port 111 passes through the exhaust pipe 171 provided outside the module case 8, flows into the exhaust passage part 140A of the evaporator 140, passes through the exhaust passage part 140A, and then evaporates. From the vessel 140 to the exhaust gas discharge pipe 82. As described above, the exhaust gas exchanges heat with the mixed gas in the mixing section 140C of the evaporator 140 and the water in the evaporation section 140B when flowing through the exhaust passage section 140A of the evaporator 140.

  In the combustion chamber 18, when the remaining fuel gas and the remaining air that have not been used for the power generation reaction are combusted in the combustion chamber 18, the pipe joint 64 </ b> C is exposed to a high temperature. As described above, when the pipe joint 64C is exposed to a high temperature, the surface of the pipe joint 64C deteriorates and peels into a powder form. However, the powder peeled from the pipe joint 64 </ b> C in this way is accommodated in the recovery space 194 in the scattering suppression cover 190 and does not scatter in the module case 8.

  When power generation air and fuel gas are supplied to each fuel cell unit 16, the fuel cell unit 16 generates electric power. The electric power generated by the fuel cell unit 16 is taken out of the module case 8 through the bus bars 200 and 202 and the current extraction terminal unit 204.

  At this time, the current extraction terminal 206A of the current extraction terminal unit 204 electrically connected to the positive electrode of the fuel cell assembly 12 has a positive potential. On the other hand, since the module case 8 is grounded, an electric field is generated between the current extraction terminal 206A connected to the positive pole and the bottom plate 8c of the module case 8. FIG. 16 is a diagram illustrating an electric field generated between the current extraction terminal connected to the positive electrode and the bottom plate of the module container. As shown in the figure, an electric field that reaches the bottom plate 8c of the module case 8 is generated from the current extraction terminal 206A connected to the positive pole along the outer peripheral surface of the inner portion 208C of the insulator 208. However, in the present embodiment, a conduction suppression groove 208D is formed around the current extraction terminal 206A, and the conduction suppression groove 208D is surrounded by an insulator 208 that is an insulator. For this reason, an electric field does not occur in the conduction suppressing groove 208D.

  A part of the shortest path connecting the current extraction terminal 206A and the bottom plate 8c of the module case 8 on the surface of the insulator 208 passes through the conduction suppressing groove 208D. As a result, the portion in the conduction suppressing groove 208D of the shortest path is not along the electric lines of force that run between the current extraction terminal 206A and the bottom plate 8c of the module case 8, and is separated from the electric lines of force. For this reason, even if the current extraction terminal 206A is coated with silver, it is possible to prevent silver from moving due to migration in the conduction suppressing groove 208D, thereby preventing a short circuit between the current extraction terminal 206A and the module case 8 due to migration. it can.

  In the present embodiment, a conduction suppression groove 208D is formed around the current extraction terminal 206A. For this reason, since the space in the conduction suppressing groove 208D is configured to have a small width, evaporated silver is difficult to enter. For this reason, the metal component containing silver scattered inside the module case 8 adheres to a portion in the conduction suppressing groove 208D in the path connecting the current extraction terminal 206A and the bottom plate 9c of the module case 8 on the surface of the insulator 208. To be suppressed. Thereby, it is possible to prevent a short circuit between the current extraction terminal 206A and the bottom plate 8c of the module case 8 due to adhesion of evaporated silver.

  Further, at the time of power generation, the silver coated on the surface of the conductive member such as the bus bars 200 and 202 evaporates, and the evaporated silver floats in the module case 8. In particular, the off-gas that does not contribute to power generation is burning in the combustion chamber 18, so that it reaches a high temperature and a large amount of silver floats. On the other hand, in this embodiment, since the current extraction terminal unit 204 is provided below the combustion chamber 18, even if the exhaust gas containing a large amount of evaporated silver rises upward, the current extraction terminal unit 204 The exhaust gas can be prevented from coming into contact with the gas.

  Further, the first protruding portion 180A and the second protruding portion 180B are provided on the closing side plate 8d of the module case 8, and the current extraction terminal unit 204 is connected to the second protruding portion 180B below the first protruding portion 180A and the second protruding portion 180B. Since the first and second isolation spaces 193A and 193B are located in the first and second isolation spaces 193A and 193B, the evaporated silver is difficult to enter.

As described above, according to the present embodiment, the following effects are produced.
According to the present embodiment, the conduction suppressing groove portion 208D that suppresses the short circuit between the current extraction terminal 206A and the bottom plate 8c of the module case 8 due to the metal component containing silver covering the surface of the insulator 208 during the power generation operation is provided. Since it is provided in the insulator 208, it is possible to prevent a short circuit from occurring between the current extraction terminal 206A and the bottom plate 8c of the module case 8 due to evaporation or migration.

As described above, according to the present embodiment, the following effects are produced.
The first stress relaxation portions 201A and 203A are provided in the connection portions 200A and 202A of the fuel cell unit 16 of the bus bars 200 and 202, and the second stress relaxation portions 201B are provided between the connection portions 200A and 202A and the connection portions 200B and 202B. , 203B are provided. As a result, the stress due to the thermal expansion of the fuel cell unit 16 is relaxed by the deformation of the first stress relaxation portions 201A and 203A, and the current extraction terminals 206A of the bus bars 200 and 202 due to variations in the mounting positions of the fuel cell assemblies 12 are alleviated. The stress generated in the side portion can be relaxed by the second stress relaxation portions 201B and 203B. For this reason, it is possible to prevent the bus bars 200 and 202 from being detached from the fuel cell unit 16 and to prevent the bus bars 200 and 202 from being damaged or deteriorated.

  In the present embodiment, the bus bars 200 and 202 are made of a single member, and the second stress relaxation portions 201B and 203B have bending points 200C1 and 200C2. According to the present embodiment, the function of relieving stress can be provided in the bus bars 200 and 202 simply by providing the bending points 200C1 and 200C2 by bending the plate-like bus bars 200 and 202 by simple processing. Further, since the second stress relaxation portions 201B and 203B are easily deformed with respect to the stress at the bending points 200C1 and 200C2, the stress concentration generated in the current extraction terminal 206A side portion of the bus bars 200 and 202 is relaxed, and the bus bars 200 and 202 Can be further suppressed, and the bus bars 200 and 202 can be prevented from being damaged or deteriorated.

  When force is applied to the bus bars 200 and 202 from the connection portions 200B and 202B to deform the second stress relaxation portions 201B and 203B, the stress applied to the portion of the bus bars 200 and 202 on the current extraction terminal 206A side can be relaxed. On the other hand, there is a possibility of causing a short circuit by contacting with surrounding members. On the other hand, in the present embodiment, the second stress relaxation portions 201B and 203B include two bending points 200C1 and 200C2, and the one bending point 200C1 bends toward one surface side of the bus bars 200 and 202. Since the other bending point 200C2 is bent toward the other surface side of the bus bars 200 and 202, the shape in the vicinity of the second stress relaxation portions 201B and 203B becomes a substantially Z shape. As a result, even if displacement occurs between the connecting portions 200A and 202A and the connecting portions 200B and 202B, the second stress relaxation portions 201B and 203B are deformed without greatly spreading to the surroundings, and thus the second stress relaxation portions 201B. , 203B can be prevented from coming into contact with surrounding members and causing a short circuit.

  In the present embodiment, the bending points 200C1 and 200C2 of the second stress relaxation portions 201B and 203B are curved shapes having a curvature. For this reason, it is possible to prevent stress from being excessively concentrated on the bending points 200C1 and 200C2 of the second stress relaxation portions 201B and 203B. Thereby, deterioration and breakage of the second stress relaxation portions 201B and 203B are suppressed, stress relaxation performance can be maintained, stress concentration generated in the current extraction terminal 206A side portion of the bus bars 200 and 202 is relaxed, and the bus bar Short circuit due to peeling of 200 and 202 and breakage and deterioration of bus bars 200 and 202 can be further suppressed. Furthermore, when the surface of the bus bars 200 and 202 is covered with a conductive film such as silver, it is possible to prevent the film from tearing.

In the present embodiment, the current extraction terminal 206A is disposed at the lower part of the module case 8, the lower end of the fuel cell unit 16 is located at the lower part of the module case 8, and the combustion chamber 18 is located above the fuel cell unit 16. Is provided. According to the present embodiment, the current extraction terminal 206 </ b> A and the fuel cell unit are disposed below the module case 8, which is lower in temperature and less affected by thermal expansion than above the fuel cell unit 16 in which the combustion chamber 18 is provided. Since the lower end of 16 is disposed, it is possible to further suppress the occurrence of stress generated in the portion of the bus bars 200 and 202 on the current extraction terminal 206A side.
In the present embodiment, since the first stress relaxation portions 201A and 203A have the curved portions 200A1 and 202A1 protruding toward the side of either surface, the stress due to thermal expansion is relaxed in the curved portions 200A1 and 202A1. Therefore, the stress generated in the bus bars 200 and 202 can be suppressed, the bus bars 200 and 202 can be prevented from being detached from the fuel cell unit 16, and the bus bars 200 and 202 can be prevented from being damaged or deteriorated. Can be prevented.

In the above-described embodiment, as shown in FIG. 12, the case where the first stress relaxation portions 201A and 203A of the bus bars 200 and 202 include the curved portions 200A1 and 202A1 has been described, but the present invention is not limited to this.
FIG. 17 is a perspective view showing a configuration of a bus bar of a solid oxide fuel cell device according to another embodiment of the present invention. FIG. 17 shows the bus bar attached to the fuel cell unit located at the negative side end of the fuel cell assembly. In the figure, the same components as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted. As shown in FIG. 17, the bus bar 300 of this embodiment differs in the structure of the connection part 300A from the bus bar 200 of 1st Embodiment. The connecting portion 300A has a pair of attachment portions 300A2 for attachment to the fuel cell unit 16 at both upper and lower ends, and the pair of attachment portions 300A2 are connected by a flat portion 300A1 that extends in the vertical direction. Projections 300A3 are formed at the upper and lower ends of the flat portion. The protrusion 300A3 is formed such that a plate material constituting the bus bar 300 protrudes toward one surface side. The protrusion 300A3 has a semicircular side sectional shape. FIG. 17 shows the bus bar 300 attached to the fuel cell unit 16 located on the negative electrode side of the fuel cell assembly 12, but it is attached to the fuel cell unit 16 located on the positive electrode side. The bus bar has the same configuration.
In the present embodiment, the first stress relaxation portion 301A includes the flat portion 300A1 of the connecting portion 300A, is flat as a whole, and includes a pair of protrusions 300A3. The protrusion 300A3 may be provided at two or more locations.

  Since the first stress relieving part 301A is adjacent to the columnar fuel cell unit 16, if a large stress deformation occurs, the fuel cell unit 16 may be contacted and a short circuit may occur. On the other hand, according to the present embodiment, the stress can be relieved by the plurality of protrusions 300A3, and other portions are formed flat, so that the stress deformation can be minimized. The occurrence of a short circuit can be prevented.

DESCRIPTION OF SYMBOLS 1 Solid oxide fuel cell apparatus 2 Fuel cell module 4 Auxiliary machine unit 6 Housing 7 Heat insulating material 8 Module case 8a Top plate 8b Side plate 8c Bottom plate 8d Closed side plate 8e Closed side plate 8f Outlet 10 Power generation chamber 12 Fuel cell assembly 16 Fuel cell unit 18 Combustion chamber 24 Water supply source 26 Pure water tank 28 Water flow rate adjustment unit 30 Fuel supply source 32 Gas shutoff valve 36 Desulfurizer 38 Fuel flow rate adjustment unit 39 Valve 40 Air supply source 42 Solenoid valve 44 Reforming air Flow rate adjusting unit 45 Power generation air flow rate adjusting unit 46 First heater 48 Second heater 50 Hot water production device 52 Control box 54 Inverter 63 Fuel supply pipe 64 Fuel gas supply pipe 64a Horizontal portion 64b Fuel supply hole 65 Hydrogen extraction for hydrodesulfurizer Pipe 66 Manifold 68 Lower support plate 74 Power generation air introduction pipe 8 Exhaust gas discharge pipe 83 Ignition device 84 Fuel cell 86 Inner electrode terminal 88 Fuel gas channel 90 Inner electrode layer 92 Outer electrode layer 94 Electrolyte layer 96 Sealing material 98 Fuel gas channel narrow tube 111 Exhaust port 112 Mixed gas supply tube 120 Gasifier 120A Mixed gas receiving part 120B Reforming part 120C Gas discharge part 120a Mixed gas supply port 120b Through hole 121 Upper case 122 Lower case 123a Partition plate 123b Partition plate 130 Exhaust gas guide member 131 Lower guide plate 131a Convex step 132 Upper guide plate 132a Recess 133 Connection plate 134 Connection plate 135 Gas insulation layer (gas reservoir)
140 Evaporator 140A Exhaust passage part 140B Evaporation part 140C Mixing part 141 Evaporator case 142 Upper case 143 Lower case 144 Intermediate plate 144a Opening 160 Air passage cover 160a Top plate 160b Side plate 161a Air passage 161b Air passage 162 Plate fin 163 Plate fin 164 Flow path direction adjustment portion 167 Opening portion 171 Exhaust pipe 172a First exhaust passage 172b Second exhaust passage 173 Third exhaust passage 174 Fourth exhaust passage 175a Plate fin 175b Plate fin 176 Exhaust concentration portion 180A First protrusion 180A1 Cut Notch portion 180B Second protrusion 180B1 Notch portion 180C Groove portion 190 Splashing suppression cover 191 First member 191A Upper surface 191B Lower surface 191C Horizontal surface 191D Front and rear surfaces 191E Through hole 191F Recessed portion 192 First Second member 192A Upper surface 192B Lower surface 192C Horizontal surface 192D Front and rear surfaces 192E Protruding portion 192F Recessed portion 192G Slit 193A First isolation space 193B Second isolation space 200 Busbar 200A Connecting portion 200A1 Bending portion 200A2 Mounting portion 200B Connecting portion 200B1 Opening 200C Stress Relaxation parts 200C1, 200C2 Bending point 201A First stress relaxation part 201B Second stress relaxation part 202A Connection part 202A2 Mounting part 203A First stress relaxation part 203B Second stress relaxation part 204 Electrical extraction unit 206 Terminal plate 206A, 206B Current extraction terminal 206A1 opening 208 insulator 208A outer part 208B enlarged diameter part 208C inner part 208D conduction suppressing groove part 300 bus bar 300A connecting part 300A1 flat part 300A2 attaching part 300A3 protruding part 301A first stress relaxation

Claims (7)

A plurality of electrically connected columnar fuel cells that perform a power generation reaction with a fuel gas and an oxidant gas; and
A module container for housing the plurality of fuel cells;
A plate-like conductive member electrically connected to the fuel cell and fixed to one end and the other end of the fuel cell;
A current extraction part fixed to the module container and for extracting the electric power generated by the fuel cell to the outside of the module container;
The conductive member includes a connecting portion connected to the one end and the other end of the fuel cell, and a connecting portion connected to the current extraction portion,
The conductive member is provided at the connecting portion and is deformed when subjected to stress, and is provided between the connecting portion and the connecting portion and deformed when subjected to stress. The solid oxide fuel cell device is characterized in that a part is formed.   2. The solid oxide fuel cell device according to claim 1, wherein the conductive member is a single member, and the second stress relaxation portion has a bending point.   The second stress relaxation portion includes two bending points. One bending point bends toward one surface of the conductive member, and the other bending point bends toward the other surface of the conductive member. The solid oxide fuel cell device according to claim 2.   4. The solid oxide fuel cell device according to claim 3, wherein the bending point of the second stress relaxation portion has a curved shape. 5. The current extraction part is disposed at a lower part of the module container,
The one end of the fuel cell is located in a lower part of the module container;
The solid oxide fuel cell device according to claim 4, wherein an off-gas combustion unit is provided on the other end side of the fuel cell.   6. The solid oxide fuel cell device according to claim 5, wherein the first stress relaxation portion has a protrusion that protrudes toward one of the surfaces. The first stress relaxation portion is flat.
The solid oxide fuel cell device according to claim 6, wherein the protrusions are provided at two or more locations.

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