JP6183777B2 - Solid oxide fuel cell device - Google Patents

Description

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

  JP 2010-526402 (Patent Document 1) includes an anode, a cathode, a gas-impermeable electrolyte between the anode and the cathode, and a first means for supplying an oxidant to the cathode; Second means for supplying fuel to the anode, wherein the second means is disposed proximate to the anode to catalyze a water gas shift reaction between carbon monoxide and water or steam in the fuel. A fuel cell assembly including a water gas shift reaction catalyst is disclosed, and the water gas shift reaction catalyst is evenly disposed on the entire electrode on the fuel gas passage side.

JP 2010-526402 A

In the development of solid oxide fuel cells, solid electrolytes have been improved, and studies have been conducted on the use of low-temperature active solid electrolytes, for example, LSGM-based solid electrolytes.
With the successful development of such a low temperature active cell, the problem of deterioration of CO performance has arisen. Since carbon monoxide is difficult to burn as a fuel at a temperature of 700 ° C. or lower, it cannot be used as a power generation fuel, and is simply exhausted.
Therefore, it is conceivable to generate hydrogen by shift reforming CO with a fuel cell assembly as described in JP 2010-526402 A. However, in such a case, since hydrogen is used in order from the upstream side of the fuel gas passage, there is a problem that the hydrogen concentration is reduced downstream. As a result, in the solid oxide fuel cell in which the fuel cell unit is composed of a single cell, fuel is exhausted downstream, causing cell deterioration.
Moreover, in the horizontal stripe type solid oxide fuel cell composed of a plurality of cells in which the fuel cell units are installed in series, the solid oxide fuel cell composed of a single cell in the fuel cell unit Since the cell area is smaller than that of the fuel cell, the load of power generation per unit area of the cell when fuel depletion occurs is large, and the effect of the fuel depletion on the cell is large. In particular, in a horizontally-striped fuel cell in which the cells are divided and arranged in the extending direction of the fuel gas passage, the current taken out from one fuel cell unit flows through each cell arranged from the upstream to the downstream of the fuel gas passage. Therefore, it is necessary to generate power so that the same amount of current flows between the cell that generates power in the state where hydrogen is abundant in the upstream and the downstream cell in which the hydrogen used for power generation has decreased. We obtained a new finding that the cells are heavily burdened and the effects of fuel depletion are prominent.
To solve this problem, it is conceivable to simply increase the amount of hydrogen to increase the downstream hydrogen concentration so that sufficient hydrogen can be supplied downstream, but this not only deteriorates the fuel utilization efficiency but also reduces the amount of hydrogen. As a result, the shift reaction that reforms CO into hydrogen and increases the hydrogen concentration is unlikely to occur, resulting in impeding the solution of problems related to the deterioration of CO performance.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a solid oxide fuel cell device that improves deterioration in CO performance and fuel utilization efficiency while suppressing cell deterioration due to fuel depletion.

In response to the above-mentioned problems, the present inventors have examined a solid oxide fuel cell that can improve deterioration of CO performance while reducing fuel waste and suppressing cell deterioration due to fuel depletion. It has been found that the above-mentioned problems can be solved by generating hydrogen by generating CO by shifting and reforming CO downstream without changing the CO as much as possible upstream of the fuel gas passage.
Therefore, the present invention
A solid oxide fuel cell comprising a fuel cell stack in which at least two fuel cell units each including a cell comprising at least a cathode electrode, a solid electrolyte and an anode electrode are electrically connected to a non-electrically conductive support surface A device,
A fuel cell module in which the fuel cell stack is housed;
A reformer capable of generating hydrogen by a steam reforming reaction that chemically reacts fuel and steam;
An evaporator for evaporating the supplied steam reforming water;
Fuel supply means for supplying the fuel reformed by the reformer by supplying fuel to the reformer, and feeding the fuel cell stack;
Water supply means for supplying reforming water to the evaporator;
Power generation oxidant gas supply means for supplying power generation oxidant gas to the fuel cell stack;
Control means for controlling the fuel cell stack to generate power;
Have
The fuel cell unit support includes a fuel gas passage through which fuel gas passes, and the fuel gas passage has a shift reforming capable of generating hydrogen by a shift reforming reaction in which water vapor and carbon monoxide are reacted. A metal catalyst for quality is disposed, and the shift reforming metal catalyst is disposed so as to be increased on the downstream side as compared with the upstream side near the reformer side of the fuel gas passage. A solid oxide fuel cell device is provided.

In one aspect of the present invention, the temperature of the fuel cell stack during power generation is operated at 700 ° C. or lower.
If the operating temperature is raised, CO can be burned and used as a power generation fuel. However, if the power generation temperature is high, the heat self-sustaining temperature is high, resulting in an increase in waste fuel. By operating the temperature of the fuel cell stack during power generation at 700 ° C. or lower, the temperature during power generation of the fuel cell stack can be lowered to increase fuel efficiency. Further, the shift reaction can be activated by lowering the temperature during power generation of the fuel cell stack, and the power generation operation and cell deterioration can be advantageously suppressed with a small amount of fuel.

In one aspect of the present invention, the fuel electrode and the shift reforming metal catalyst are arranged to face each other on the downstream side of the support on which the shift reforming metal catalyst is disposed. Yes.
As a result, it is possible to reliably generate power using hydrogen generated in the shift reaction as a fuel, and it is possible to raise the temperature in the downstream part where the generated heat is less likely to be generated when the operating temperature is lowered, due to the heat generated by the shift reaction. Can be stabilized.

In one aspect of the present invention, the shift reforming metal catalyst is disposed at least at a position downstream of the support and where the most downstream fuel electrode is present.
Thereby, by supplying hydrogen by the shift reaction to the most downstream cell with the highest risk of fuel depletion, the risk of cell deterioration can be greatly reduced.

In one embodiment of the present invention, the shift reforming metal catalyst is disposed not on the upstream side of the support but on the downstream side.
As a result, the shift reaction is concentrated on the downstream side, and the shift reaction is not performed on the upstream side, so that cell deterioration can be further reduced.

In one embodiment of the present invention, the shift reforming metal catalyst is not located in the intermediate region of the support but is disposed only on the downstream side.
The most downstream portion has the greatest hydrogen concentration dilution and concentration unevenness. In order to eliminate this risk, it is desirable that the shift reforming metal catalyst is not in the intermediate region and is surely concentrated downstream.

In one embodiment of the present invention, the support is made of a porous non-electrically conductive material, and is molded so that the shift reforming metal catalyst is exposed in the porous material.
If the metal catalyst for shift reforming is arranged so as to be exposed in the porous, not only the surface area increases, but also the hydrogen generated in the porous can be reliably transmitted to the fuel electrode, and there is a risk of wasteful CO emissions. It is possible to suppress cell deterioration more reliably.

  In one aspect of the present invention, the shift reforming metal catalyst is not exposed on the fuel electrode side of the support, and the shift reforming metal catalyst is exposed only on the fuel gas passage side of the support. Yes. When a catalyst is placed in the porous material, there is a risk that a conductive path is formed on the support, which should be a non-conductive member, via the catalyst. By adopting such a mode, the risk can be prevented.

In one aspect of the present invention, a metal member that dissipates heat associated with the shift reforming reaction is provided at the most downstream portion of the fuel cell unit, and the exhaust passage is constituted by the member.
Since shift reforming is an exothermic reaction, the shift reaction can be promoted by releasing heat through the metal member. In addition, it is not desirable that hydrogen is generated by shift reforming, but that excessive heat is generated only in the downstream portion, resulting in thermal unevenness in the cell. It is desirable to provide a metal member as a member constituting the passage and use it as a heat radiating material.

  In one aspect of the present invention, the shift reforming metal catalyst is Ni, and is molded so that Ni is exposed only in the porous body of the downstream support. Since it is only necessary to mold inexpensive Ni so as to be exposed in the porous body, it can be manufactured at a lower cost.

  According to the solid oxide fuel cell of the present invention, CO is not shifted and reformed as much as possible upstream of the fuel gas passage, and CO is shifted and reformed downstream to generate hydrogen to be used as a fuel for power generation. Fuel depletion in the downstream cell portion can be suppressed. In addition, according to the solid oxide fuel cell of the present invention, it is possible to suppress CO emissions. Furthermore, according to the solid oxide fuel cell of the present invention, CO generated by using hydrogen upstream can also be shift-reformed to hydrogen downstream.

1 is an overall configuration diagram showing a fuel cell device according to an embodiment of the present invention. It is front sectional drawing which shows the fuel cell module of the fuel cell apparatus by one Embodiment of this invention. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. 1A is a partial cross-sectional view showing a fuel cell unit of a fuel cell device according to an embodiment of the present invention, and FIG. 1 is a perspective view showing a fuel cell stack of a fuel cell device according to an embodiment of the present invention (first embodiment). 1 is a block diagram showing a fuel cell device according to an embodiment of the present invention. 1 is a perspective view of a reformer of a fuel cell device according to an embodiment of the present invention. FIG. 5 is a perspective view showing the inside of the reformer with the top plate removed in the fuel cell device according to an embodiment of the present invention. 1 is a cross-sectional plan view showing a flow of fuel inside a reformer in a fuel cell device according to an embodiment of the present invention. 1 is a perspective view showing a metal case and an air heat exchanger housed in a housing in a fuel cell device according to an embodiment of the present invention. In the fuel cell device by one Embodiment of this invention, it is sectional drawing which shows the positional relationship of the heat insulating material for heat exchangers, and an evaporation part. It is a schematic diagram of the reaction that occurs in the fuel gas passage in the fuel cell stack of the fuel cell device according to one embodiment of the present invention. It is a schematic diagram which shows the reaction which arises in the structure of the fuel cell unit of the fuel cell unit of the fuel cell device by one embodiment of the present invention, and a fuel gas passage (second embodiment).

In the solid oxide fuel cell of the present invention, at least two fuel cell units each including a cell composed of at least a cathode electrode, a solid electrolyte, and an anode electrode are electrically connected in series or in parallel on the surface of a support having no electrical conductivity. It has a connected fuel cell stack. In the present invention, the fuel cell unit can include one or a plurality of cells, for example, 2 to 40 cells, and the upper limit thereof is particularly limited as long as it is within the allowable range in view of the strength of the cells. Is not to be done. When a fuel cell unit includes a plurality of cells, it is generally called a horizontal stripe solid oxide fuel cell.
In the solid oxide fuel cell of the present invention, the shift reforming metal catalyst is disposed on the fuel gas flow path side of the support of the fuel cell unit, but the upstream support close to the reformer side is provided. Compared to the downstream side support body, it is more disposed.
For example, when distinguishing between the upstream side and the downstream side, it may mean a portion that occupies half the length of the entire fuel cell unit. Further, when distinguishing the upstream side, the intermediate region, and the downstream side, it may mean a portion that occupies 1/3 of the total length of the fuel cell unit, but these portions have the lengths as described above. It is not necessary to interpret it strictly as an occupying part, and it should be understood flexibly within the scope of common general technical knowledge.
Of course, it may have a concentration gradient such that the amount of the shift reforming metal catalyst gradually disposed from the upstream side to the downstream side is increased, and the shift reforming metal catalyst is located upstream. The concentration gradient may be such that the amount of the shift reforming metal catalyst gradually disposed from the intermediate region to the downstream side is not disposed.
The fuel cell stack is formed by connecting a plurality of, for example, 2 to 160 fuel cell units electrically in series or in parallel, but the number of fuel cell units is particularly limited. is not.

Examples of the shift reforming metal catalyst include nickel, copper, platinum and the like, but are not limited thereto. Preferably, nickel is used.
The shift reaction is represented by the following formula (1).
CO + H ₂ O → CO ₂ + H ₂ (1)
This shift reaction produces carbon dioxide and hydrogen from carbon monoxide and water vapor. Therefore, in the present embodiment, it is possible to improve the fuel utilization efficiency by improving the deterioration of the CO performance while suppressing the cell deterioration due to fuel exhaustion.
Here, it is known that the shift reaction occurs in a temperature range of about 450 ° C. to about 700 ° C. Therefore, in an aspect in which the fuel cell stack is operated at a temperature during power generation of 700 ° C. or less, the shift reaction can be more activated, and the power generation operation and cell deterioration can be advantageously suppressed with less fuel. it can.

When nickel is disposed as a shift reforming metal catalyst on the fuel gas channel side of the support, a steam reforming reaction can occur in the fuel gas channel.
This steam reforming reaction is represented, for example, by the following formula (2).
CH ₄ + H ₂ O → CO + 3H ₂ (2)
The CO generated here is used for the shift reaction and converted to H ₂ as described above. Further, the steam reforming reaction is an endothermic reaction, and a gradual heating effect on the heat generated by the shift reaction can be expected. Furthermore, a decrease in diffusion resistance due to H ₂ O consumption can be expected.
Here, with reference to FIG. 12, the structure of the support body in the fuel cell unit of the fuel cell apparatus according to the embodiment of the present invention, and the reaction in the fuel gas passage formed inside thereof will be described.
As shown in FIG. 12, the fuel gas passage in the fuel cell unit is formed inside the support. In one embodiment of the present invention shown in FIG. 12, the support 202 is provided with no shift reforming metal catalyst on the upstream side, and the shift reforming metal catalyst is arranged on the downstream side. It has a body 201. Therefore, it is possible to shift-modify CO only on the downstream side of the support without shifting the CO on the upstream side of the support. As described above, when nickel is disposed as the shift reforming metal catalyst on the fuel gas channel side of the support, a steam reforming reaction can occur in the fuel gas channel.

Next, a solid oxide fuel cell (SOFC) 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 (SOFC) according to an embodiment of the present invention. As shown in FIG. 1, a solid oxide fuel cell (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 case 8 constituting a sealed space surrounded by a heat insulating material 7 that is an outer heat insulating material is accommodated in the housing 6. A fuel cell assembly 12 that performs a power generation reaction with fuel and an oxidant (air) is disposed in a power generation chamber 10 that is a lower portion inside the case 8.
In the first embodiment of the present invention, the fuel cell assembly 12 includes ten fuel cell stacks 14 (see FIG. 5), and the fuel cell stack 14 includes 16 fuel cell units 16. (See FIG. 4). Thus, the fuel cell assembly 12 has 160 fuel cell units 16, and all of these fuel cell units 16 are connected in series. In the present embodiment, the fuel cell unit 16 is configured to include one cell in one unit.

A combustion chamber 18 is formed above the above-described power generation chamber 10 inside the case 8 of the fuel cell module 2. In this combustion chamber 18, residual fuel and residual oxidant (air) that have not been used for the power generation reaction. Burns and produces exhaust gas.
Further, a reformer 20 for reforming the fuel is disposed above the combustion chamber 18, and the reformer 20 is heated to a temperature at which a reforming reaction can be performed by the combustion heat of the residual gas. Yes. Further, an air heat exchanger 22 is disposed above the reformer 20 to heat the air by receiving heat from the reformer 20 and suppress a temperature drop of the reformer 20.

  Next, the auxiliary unit 4 stores a pure water tank 26 that stores water from a water supply source 24 such as tap water and uses the filter to obtain pure water, and a water flow rate that adjusts the flow rate of the water supplied from the water storage tank. An adjustment unit 28 (such as a “water pump” driven by a motor) is provided. In addition, the auxiliary unit 4 adjusts the flow rate of the fuel gas, the gas shutoff valve 32 for shutting off the fuel supplied from the fuel supply source 30 such as city gas, the desulfurizer 36 for removing sulfur from the fuel gas, A fuel flow rate adjustment unit 38 (such as a “fuel pump” driven by a motor) is provided. Further, the auxiliary unit 4 includes an electromagnetic valve 42 that shuts off air that is an oxidant 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 (such as an “air blower” driven by a motor), a first heater 46 for heating the reforming air supplied to the reformer 20, and a second for heating the power generating air supplied to the power generation chamber And a heater 48. The first heater 46 and the second heater 48 are provided in order to efficiently raise the temperature at startup, but may be omitted.

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 internal structure of a solid oxide fuel cell (SOFC) fuel cell module according to an embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a side sectional view showing a solid oxide fuel cell (SOFC) fuel cell module according to an embodiment of the present invention, and FIG. 3 is a sectional view taken along line III-III in FIG. .
As shown in FIGS. 2 and 3, the sealed case 8 in the housing 6 of the fuel cell module 2 includes the fuel cell assembly 12, the reformer 20, and the air in order from the bottom as described above. A heat exchanger 22 is arranged.

  The reformer 20 is provided with a pure water introduction pipe 60 for introducing pure water and a reformed gas introduction pipe 62 for introducing reformed fuel gas and reforming air to the upstream end side thereof. In the reformer 20, an evaporator 20a and a reformer 20b are formed in this order from the upstream side, and the evaporator 20a and the reformer 20b are filled with a reforming catalyst. The fuel gas and air mixed with the steam (pure water) introduced into the reformer 20 are reformed by the reforming catalyst filled in the reformer 20. 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.

  A fuel gas supply pipe 64 is connected to the downstream end side of the reformer 20, and the fuel gas supply pipe 64 extends downward and further in an manifold 66 formed below the fuel cell assembly 12. It extends horizontally. 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 the reformed 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 stack 14 described above is attached above the manifold 66, and the fuel gas in the manifold 66 flows into the fuel cell unit 16. Supplied.

Next, an air heat exchanger 22 is provided above the reformer 20.
Further, as shown in FIG. 2, an ignition device 83 for starting combustion of fuel gas and air is provided in the combustion chamber 18.

Next, the fuel cell unit 16 will be described with reference to FIG. FIG. 4A is a partial cross-sectional view showing a fuel cell unit of a solid oxide fuel cell (SOFC) according to the first embodiment of the present invention. FIG. 4B is a cross-sectional view of the fuel cell unit.
As shown in FIG. 4A, the fuel cell unit 16 includes a fuel cell 84 and inner electrode terminals 86 respectively connected to the vertical ends of the fuel cell 84.
The fuel cell 84 is a tubular structure that extends in the vertical direction. The fuel cell 84 has a cylindrical support 89 that forms a fuel gas flow path 88 as an internal passage therein, a cylindrical inner electrode layer 90, and a cylindrical shape. An outer electrode layer 92 and an electrolyte layer 94 between the inner electrode layer 90 and the outer electrode layer 92 are provided. The inner electrode layer 90 is a fuel electrode through which fuel gas passes and becomes a (−) electrode (anode), while the outer electrode layer 92 is an air electrode in contact with air, and a (+) electrode (cathode). It has become. As described above, the shift reforming metal catalyst is disposed on the fuel gas flow path side of the support 89. In the present embodiment, the support 89 includes an upstream support 89c on which no shift reforming metal catalyst is disposed, an intermediate support 89b on which a small amount of shift reforming metal catalyst is disposed, and shift modification. It is comprised from the downstream support body 89a in which the quality metal catalyst is arrange | positioned more than an intermediate | middle area.

Since the inner electrode terminals 86 attached to the upper end side and the lower end side of the fuel cell unit 16 have 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. A fuel gas passage 98 communicating with the fuel gas passage 88 inside the support 89 is formed at the center of the inner electrode terminal 86.
In the solid oxide fuel cell (SOFC) according to an embodiment of the present invention, a metal member that dissipates heat associated with the shift reforming reaction is provided at the most downstream portion of the fuel cell unit in the fuel cell stack 14. An exhaust passage may be provided.

The inner electrode layer 90 is, for example, a mixture of NiO and zirconia doped with at least one selected from rare earth elements such as Ca, Y, and Sc, NiO and ceria doped with at least one selected from rare earth elements. It can be formed from at least one of a mixture, a mixture of NiO and a lanthanum garade doped with at least one selected from Sr, Mg, Co, Fe, Cu, but is not limited thereto. . The inner electrode layer 90 may be a single layer or a multilayer. As an example of the case where the inner electrode is a multi-layer fuel electrode, for example, Ni / YSZ (yttria stabilized zirconia) is used on the support side, and Ni / GDC (Gd ₂ O ₃ —CeO ₂ ) (= fuel) on the electrolyte side. Electrode catalyst layer).

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, However, the present invention is not limited to this. Preferably, the general formula La _1-a Sr _a Ga _1-bc Mg _b Co _c O ₃ (where 0.05 ≦ a ≦ 0.3, 0 <b <0.3, 0 ≦ c ≦ 0.15) ) Lanthanum gallate oxide (LSGM). Here, on the fuel electrode side, ceria (Ce _1-x La _x O ₂ (where 0.3 <x <0.5)) in which La is dissolved may be provided as a reaction suppression layer. The reaction suppression layer is preferably Ce _0.6 La _0.4 O ₂ . The solid electrolyte may be a single layer or a multilayer. As an example of the case where the solid electrolyte is a multilayer, a reaction suppression layer such as Ce _0.6 La _0.4 O ₂ can be used between the fuel electrode and the electrolyte layer made of LSGM, for example.

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 can be formed from at least one of lanthanum cobaltite doped with at least one selected from, silver, and the like, but is not limited thereto. The outer electrode layer 92 may be a single layer or a multilayer. As an example when the outer electrode is a multilayer air electrode, for example, L _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ (= air electrode catalyst layer) is used on the electrolyte side, and L _0.6 Sr _0.4 Co _0.8 Fe is used as the outermost layer. _0.2 O ₃ (= air electrode) can be used.

  The support 89 is made of a non-conductive material and can be formed of, for example, alumina, zirconia, spinel, forsterite, magnesia, titania, or a composite material thereof, but is not limited thereto. The support 89 can be formed of a porous material, and can be arranged so that the shift reforming metal catalyst is exposed in the porous material. Preferably, forsterite is used as the support.

Next, the structure of the fuel cell 84 will be described in detail with reference to FIG.
As shown in FIG. 4B, in the first embodiment of the present invention, the inner electrode layer 90 includes a first fuel electrode 90d and a second fuel electrode 90e. The electrolyte layer 94 is composed of a first electrolyte 94a and a second electrolyte 94b, and the outer electrode layer 92 is composed of an air electrode 92a and a current collecting layer 92b.

  In the present embodiment, the first fuel electrode 90d is formed by firing a mixture of NiO and YSZ, which is Y-doped zirconia, into a cylindrical shape. The second fuel electrode 90e is formed by depositing a mixture of NiO and GDC, which is a ceria doped with Gd, on the outside of the first fuel electrode 90d.

  In the present embodiment, the first electrolyte 94a is formed by laminating the LDC 40, which is ceria doped with lanthanum, on the outside of the second fuel electrode 90e. Furthermore, the second electrolyte 94b is formed by laminating LSGM, which is lanthanum gallate doped with Sr and Mg, on the outside of the first electrolyte 94a. A fired body was formed by firing the formed body.

  In the present embodiment, the air electrode 92a is formed by depositing LSCF, which is lanthanum cobaltite doped with Sr and Fe, on the outside of the fired body. The current collecting layer 92b is configured by forming an Ag layer outside the air electrode 92a.

In the present embodiment, the support 89 is made of forsterite.
In this embodiment, as shown in FIG. 4, the shift reforming metal catalyst made of nickel is arranged on the fuel gas flow path side of the support 89, but the upstream support close to the reformer side is provided. A small amount of Ni is disposed on the support in the intermediate region, and more than the intermediate region is disposed on the downstream support.
As a result, a shift reaction does not occur as much as possible in the upstream of the fuel gas passage, and hydrogen is generated by performing a shift reaction in the downstream to provide a fuel for power generation.
Here, it is known that the shift reaction occurs in a temperature range of about 450 ° C. to about 700 ° C. In this embodiment, the temperature during power generation of the fuel cell stack is operated at 700 ° C. or lower. Thereby, the activation of the shift reaction can be further promoted, and the power generation operation and the cell deterioration can be advantageously suppressed with a small amount of fuel.

Next, the fuel cell stack 14 will be described with reference to FIG. FIG. 5 is a perspective view showing a fuel cell stack of a solid oxide fuel cell (SOFC) according to an embodiment of the present invention.
As shown in FIG. 5, the fuel cell stack 14 includes 16 fuel cell units 16, and the lower end side and the upper end side of these fuel cell units 16 are a ceramic lower support plate 68 and an upper side, respectively. It is supported by the support plate 100. The lower support plate 68 and the upper support plate 100 are formed with through holes 68a and 100a through which the inner electrode terminal 86 can pass.

  Furthermore, a current collector 102 and an external terminal 104 are attached to the fuel cell unit 16. The current collector 102 includes a fuel electrode connection portion 102a that is electrically connected to an inner electrode terminal 86 attached to the inner electrode layer 90 that is a fuel electrode, and an entire outer peripheral surface of the outer electrode layer 92 that is an air electrode. And an air electrode connecting portion 102b electrically connected to each other. The air electrode connecting portion 102b is formed of a vertical portion 102c extending in the vertical direction on the surface of the outer electrode layer 92 and a plurality of horizontal portions 102d extending in a horizontal direction along the surface of the outer electrode layer 92 from the vertical portion 102c. Has been. The fuel electrode connection portion 102a is linearly directed obliquely upward or obliquely downward from the vertical portion 102c of the air electrode connection portion 102b toward the inner electrode terminal 86 positioned in the vertical direction of the fuel cell unit 16. It extends.

  Further, the inner electrode terminals 86 at the upper end and the lower end of the two fuel cell units 16 located at the ends of the fuel cell stack 14 (the far left side and the near side in FIG. 5) are external terminals, respectively. 104 is connected. These external terminals 104 are connected to the external terminals 104 (not shown) of the fuel cell unit 16 at the end of the adjacent fuel cell stack 14, and as described above, the 160 fuel cell units 16 Everything is connected in series.

Next, sensors and the like attached to the solid oxide fuel cell (SOFC) according to the present embodiment will be described with reference to FIG. FIG. 6 is a block diagram illustrating a solid oxide fuel cell (SOFC) according to an embodiment of the present invention.
As shown in FIG. 6, the solid oxide fuel cell 1 includes a control unit 110, and the control unit 110 includes operation buttons such as “ON” and “OFF” for operation by the user. An operation device 112, a display device 114 for displaying various data such as a power generation output value (wattage), and a notification device 116 for issuing a warning (warning) in an abnormal state are connected. The notification device 116 may be connected to a remote management center and notify the management center of an abnormal state.

Next, signals from various sensors described below are input to the control unit 110.
First, the combustible gas detection sensor 120 is for detecting a gas leak, and is attached to the fuel cell module 2 and the auxiliary unit 4.
The CO detection sensor 122 detects whether or not CO in the exhaust gas originally discharged to the outside through the exhaust gas passage 80 or the like leaks to an external housing (not shown) that covers the fuel cell module 2 and the auxiliary unit 4. Is to do.
The hot water storage state detection sensor 124 is for detecting the temperature and amount of hot water in a water heater (not shown).

The power state detection sensor 126 is for detecting the current and voltage of the inverter 54 and the distribution board (not shown).
The power generation air flow rate detection sensor 128 is for detecting the flow rate of power generation air supplied to the power generation chamber 10.
The reforming air flow sensor 130 is for detecting the flow rate of the reforming air supplied to the reformer 20.
The fuel flow sensor 132 is for detecting the flow rate of the fuel gas supplied to the reformer 20.

The water flow rate sensor 134 is for detecting the flow rate of pure water supplied to the reformer 20.
The water level sensor 136 is for detecting the water level of the pure water tank 26.
The pressure sensor 138 is for detecting the pressure on the upstream side outside the reformer 20.
The exhaust temperature sensor 140 is for detecting the temperature of the exhaust gas flowing into the hot water production apparatus 50.

As shown in FIG. 3, the power generation chamber temperature sensor 142 is provided on the front side and the back side in the vicinity of the fuel cell assembly 12, and detects the temperature in the vicinity of the fuel cell stack 14 to thereby detect the fuel cell stack. 14 (ie, the fuel cell 84 itself) is estimated.
The combustion chamber temperature sensor 144 is for detecting the temperature of the combustion chamber 18.
The exhaust gas chamber temperature sensor 146 is for detecting the temperature of the exhaust gas in the exhaust gas chamber 78.
The reformer temperature sensor 148 is for detecting the temperature of the reformer 20, and calculates the temperature of the reformer 20 from the inlet temperature and the outlet temperature of the reformer 20.
The outside air temperature sensor 150 is for detecting the temperature of the outside air when the solid oxide fuel cell (SOFC) is disposed outdoors. Further, a sensor for measuring the humidity or the like of the outside air may be provided.

  Signals from these sensors are sent to the control unit 110, and the control unit 110, based on data based on these signals, the water flow rate adjustment unit 28, the fuel flow rate adjustment unit 38, the reforming air flow rate adjustment unit 44, A control signal is sent to the power generation air flow rate adjusting unit 45 to control each flow rate in these units.

Next, the detailed configuration of the reformer 20 will be described with reference to FIGS.
FIG. 7 is a perspective view of the reformer 20, and FIG. 8 is a perspective view showing the inside of the reformer 20 with the top plate removed. FIG. 9 is a plan sectional view showing the flow of fuel inside the reformer 20.

  As shown in FIG. 7, the reformer 20 is a rectangular parallelepiped metal box, and is filled with a reforming catalyst for reforming fuel. Further, a pure water introduction pipe 60 for introducing water and a to-be-reformed gas introduction pipe 62 for introducing fuel and reforming air are connected to the upstream side of the reformer 20. Further, a fuel gas supply pipe 64 for discharging the internally reformed fuel is connected to the downstream side of the reformer 20. The reformer 20 is provided with eight vents 20c along the longitudinal direction. These vents 20c are provided from the bottom surface to the top surface of the reformer 20 so that the combustion gas combusted in the combustion chamber 18 (FIG. 2) below the reformer 20 can smoothly escape above the reformer 20. The vents 20 c are provided so as to penetrate therethrough, and are not communicated with the interior of the reformer 20.

  As shown in FIG. 8, inside the reformer 20, an evaporation unit 20a that is an evaporation chamber is provided on the upstream side, and a reforming unit 20b is provided on the downstream side adjacent to the evaporation unit 20a. It has been. A winding path is formed in the evaporation unit 20a by arranging a plurality of partition plates. The water introduced into the reformer 20 is evaporated in the evaporation unit 20a in a state where the temperature is increased, and becomes water vapor. Further, the fuel gas and the reforming air introduced into the reformer 20 are mixed with the water vapor while passing through the winding path of the evaporation unit 20a.

On the other hand, a meandering passage is formed in the reforming section 20b by arranging a plurality of partition plates, and the passage is filled with a catalyst. The fuel gas and the reforming air mixed in the evaporation unit 20a undergo a partial oxidation reforming reaction while passing through the passage of the reforming unit 20b. Further, when a mixture of fuel gas, water vapor, and reforming air is introduced from the evaporation unit 20a, a partial oxidation reforming reaction and a steam reforming reaction occur in the reforming unit 20b. Further, when a mixture of fuel gas and water vapor is introduced from the evaporation unit 20a, only the steam reforming reaction occurs in the reforming unit 20b.
In the present embodiment, the evaporation unit and the reforming unit are integrally configured to form one reformer. However, as a modified example, a reformer including only the reforming unit is provided. An evaporation chamber can also be provided adjacent to the upstream side.

  As shown in FIG. 9, the fuel gas, water, and reforming air introduced into the evaporation section 20a of the reformer 20 first meander and flow in the transverse direction of the reformer 20, and then the two passages. And is meandered in the longitudinal direction of the reformer 20. Further, the passages are merged again and connected to the reforming unit 20 b at the central portion of the reformer 20. The fuel or the like introduced into the reforming section 20b flows in the longitudinal direction in the center of the reforming section 20b, then splits into two, turns back, and the two passages turn back again toward the downstream end of the reforming section 20b. Then, they are merged and flow into the fuel gas supply pipe 64. The fuel is reformed by the catalyst filled in the passage while passing through the meandering passage.

  Next, referring to FIGS. 10 and 11 again, and referring again to FIGS. 2 and 3, the structure of the air heat exchanger 22 which is a heat exchanger for the power generation oxidant gas will be described in detail. FIG. 10 is a perspective view showing the metal case 8 and the air heat exchanger 22 housed in the housing 6. FIG. 11 is a cross-sectional view showing the positional relationship between the heat exchanger for heat exchanger and the evaporation section.

  As shown in FIG. 10, the air heat exchanger 22 is a heat exchanger disposed above the case 8 in the fuel cell module 2. Further, as shown in FIGS. 2 and 3, a combustion chamber 18 is formed inside the case 8, and a plurality of fuel cell units 16, a reformer 20 and the like are accommodated therein. 22 is located above these. The air heat exchanger 22 collects and uses the heat of the combustion gas that is combusted in the combustion chamber 18 and discharged as exhaust gas so as to preheat the power generation air introduced into the fuel cell module 2. It is configured. Further, as shown in FIG. 10, an evaporation chamber heat insulating material 23, which is an evaporation chamber temperature increasing heat insulating layer, is sandwiched between the upper surface of the case 8 and the bottom surface of the air heat exchanger 22. Are arranged to be. Furthermore, the outside of the air heat exchanger 22 and the case 8 shown in FIG. 10 is covered with a heat insulating material 7 as an outer heat insulating material (FIG. 2).

  As shown in FIGS. 2 and 3, the air heat exchanger 22 includes a plurality of combustion gas pipes 70 and a power generation air flow path 72. As shown in FIG. 2, an exhaust gas collecting chamber 78 is provided at one end of the plurality of combustion gas pipes 70, and the exhaust gas collecting chamber 78 is communicated with each combustion gas pipe 70. ing. Further, an exhaust gas discharge pipe 82 is connected to the exhaust gas collecting chamber 78. Further, the other end of each combustion gas pipe 70 is open, and this open end communicates with the combustion chamber 18 in the case 8 via a communication opening 8 a formed on the upper surface of the case 8. Has been.

  The combustion gas pipe 70 is a plurality of metal circular pipes oriented in the horizontal direction, and the circular pipes are arranged in parallel. On the other hand, the power generation air flow path 72 is constituted by a space outside each combustion gas pipe 70. A power generation air introduction pipe 74 is connected above one end of the power generation air flow path 72, and the air outside the fuel cell module 2 passes through the power generation air introduction pipe 74 for power generation. It is introduced into the air flow path 72. Further, a pair of communication flow paths 76 (FIGS. 3 and 10) are connected to both side surfaces of the other end of the power generation air flow path 72, and the power generation air flow path 72 and each communication flow path 76 are connected. Are communicated with each other via an exit port 76a.

  As shown in FIG. 3, a power generation air supply passage 77 is provided on each side surface of the case 8. Each communication channel 76 provided on both side surfaces of the air heat exchanger 22 communicates with an upper portion of a power generation air supply channel 77 provided on both side surfaces of the case 8. In addition, a large number of air outlets 77 a are arranged in the horizontal direction at the lower portion of each power generation air supply passage 77. The power generation air supplied through each power generation air supply path 77 is injected toward the lower side surface of the fuel cell stack 14 in the fuel cell module 2 from a large number of air outlets 77a.

A rectifying plate 21 that is a partition wall is attached to the ceiling surface inside the case 8, and the rectifying plate 21 has an opening 21 a.
The rectifying plate 21 is a plate member disposed horizontally between the ceiling surface of the case 8 and the reformer 20. The rectifying plate 21 is configured to adjust the flow of gas flowing upward from the combustion chamber 18 and guide it to the inlet (communication opening 8a) of the air heat exchanger 22. The power generation air and the combustion gas traveling upward from the combustion chamber 18 flow into the upper side of the rectifying plate 21 through the opening 21 a provided in the center of the rectifying plate 21, and the upper surface of the rectifying plate 21 and the ceiling surface of the case 8. 2 flows to the left in FIG. 2 and is led to the inlet of the heat exchanger 22 for air. Moreover, as shown in FIG. 11, the opening 21a is provided above the reforming unit 20b of the reformer 20, and the gas rising through the opening 21a is on the opposite side of the evaporation unit 20a. , Flows to the left exhaust passage 21b in FIGS. For this reason, the space above the evaporation unit 20a (the right side in FIGS. 2 and 11) acts as a gas retention space 21c in which the flow of exhaust gas is slower than the space above the reforming unit 20b.

  The heat insulating material 23 for the evaporation chamber is a heat insulating material attached to the bottom surface of the air heat exchanger 22 so as to substantially cover the whole. Therefore, the heat insulating material 23 for evaporation chamber is arrange | positioned over the whole evaporation part 20a. The evaporating chamber heat insulating material 23 is formed so that the high-temperature gas in the exhaust passage 21 b and the gas retention space 21 c formed between the upper surface of the rectifying plate 21 and the ceiling surface of the case 8 is moved to It arrange | positions so that it may suppress direct heating. For this reason, the heat directly transmitted to the bottom surface of the air heat exchanger 22 from the exhaust gas remaining in the exhaust passage above the evaporation unit 20a is reduced, and the temperature around the evaporation unit 20a is likely to rise.

  In addition, the heat insulating material 23 for the evaporation chamber includes a heat insulating material 7 that is an outer heat insulating material covering the case 8 of the fuel cell module 2 and the entire air heat exchanger 22 in order to suppress the dissipation of heat to the outside air. Apart from this, it is a heat insulating material arranged inside the heat insulating material 7. The heat insulating material 7 is configured to have higher heat insulating properties than the heat insulating material 23 for the evaporation chamber. That is, the thermal resistance between the inner surface and the outer surface of the heat insulating material 7 is larger than the thermal resistance between the upper surface and the lower surface of the evaporation chamber heat insulating material 23. That is, when the heat insulating material 7 and the evaporation chamber heat insulating material 23 are made of the same material, the heat insulating material 7 is made thicker than the evaporation chamber heat insulating material 23.

Next, the flow of fuel, power generation air, and exhaust gas during the power generation operation of the solid oxide fuel cell 1 will be described.
First, fuel is introduced into the evaporating section 20a of the reformer 20 through the reformed gas introduction pipe 62, and pure water is introduced into the evaporating section 20a through the pure water introduction pipe 60. During the power generation operation, since the evaporation unit 20a is heated to a high temperature, the pure water introduced into the evaporation unit 20a is evaporated relatively quickly to become water vapor. The evaporated water vapor and fuel are mixed in the evaporation unit 20 a and flow into the reforming unit 20 b of the reformer 20. The fuel introduced into the reforming section 20b together with the steam is steam reformed here and reformed into a fuel gas rich in hydrogen. The fuel reformed in the reforming unit 20b goes down through the fuel gas supply pipe 64 and flows into the manifold 66 which is a dispersion chamber.

  The manifold 66 is a rectangular parallelepiped space having a relatively large volume, which is disposed on the lower side of the fuel cell stack 14, and a plurality of holes provided on the upper surface thereof constitute each fuel cell constituting the fuel cell stack 14. It communicates with the inside of the unit 16. The fuel introduced into the manifold 66 flows out from the upper end of the fuel cell unit 16 through the many holes provided on the upper surface thereof, through the fuel electrode side of the fuel cell unit 16, that is, through the inside of the fuel cell unit 16. . Further, when hydrogen gas as a fuel passes through the inside of the fuel cell unit 16, it reacts with oxygen in the air passing outside the fuel cell unit 16 as an air electrode (oxidant gas electrode) to generate a charge. Is done. The remaining fuel that is not used for power generation flows out from the upper end of each fuel cell unit 16 and is combusted in a combustion chamber 18 provided above the fuel cell stack 14.

  On the other hand, the power generation air as the oxidant gas is sent into the fuel cell module 2 through the power generation air introduction pipe 74 by the power generation air flow rate adjustment unit 45 as the power generation oxidant gas supply means. The air sent into the fuel cell module 2 is introduced into the power generation air passage 72 of the air heat exchanger 22 via the power generation air introduction pipe 74 and preheated. The preheated air flows out to each communication channel 76 via each outlet port 76a (FIG. 3). The power generation air flowing into each communication channel 76 flows downward through the power generation air supply passages 77 provided on both side surfaces of the fuel cell module 2, and the fuel cell stack 14 from a number of outlets 77a. Toward the power generation chamber 10.

  The air injected into the power generation chamber 10 comes into contact with the outer surface of each fuel cell unit 16 on the air electrode side (oxidant gas electrode side) of the fuel cell stack 14, and a part of oxygen in the air is in contact with it. Used for power generation. Moreover, the air injected to the lower part of the power generation chamber 10 through the blower outlet 77a rises in the power generation chamber 10 while being used for power generation. The air rising in the power generation chamber 10 burns the fuel flowing out from the upper end of each fuel cell unit 16. The combustion heat generated by this combustion heats the evaporation section 20a and the reforming section 20b of the reformer 20 disposed above the fuel cell stack 14. The combustion gas generated by burning the fuel heats the upper reformer 20 and then flows into the upper side of the rectifying plate 21 through the opening 21 a above the reformer 20. The combustion gas that has flowed into the upper side of the rectifying plate 21 is guided to the communication opening 8 a that is the inlet of the air heat exchanger 22 through the exhaust passage 21 b formed by the rectifying plate 21. The combustion gas that has flowed into the air heat exchanger 22 from the communication opening 8 a flows into the open end of each combustion gas pipe 70 and flows through the power generation air flow path 72 outside each combustion gas pipe 70. Are exchanged with each other and collected in an exhaust gas collecting chamber 78. The exhaust gas collected in the exhaust gas collection chamber 78 is discharged to the outside of the fuel cell module 2 through the exhaust gas discharge pipe 82. As a result, the evaporation of water in the evaporation unit 20a and the steam reforming reaction, which is an endothermic reaction in the reforming unit 20b, are promoted, and the power generation air in the air heat exchanger 22 is preheated.

Next, a second embodiment of the present invention will be described with reference to FIG. In the present embodiment, the fuel cell unit is configured to include 10 cells connected in series in one unit. Thus, in this specification, in the case of a horizontal stripe type solid oxide fuel cell, a unit corresponding to each horizontal stripe is referred to as a cell. Each cell is connected by an interconnector 208 for connecting adjacent cells in series.
In the present embodiment, adjacent fuel cell units arranged in the same manner as in the first embodiment are electrically connected in series or in parallel so that the same level of output can be taken out as a whole. Since a series voltage of 10 cells can be obtained from one fuel cell unit, the same power can be taken out by a smaller number of fuel cell units than the total number of fuel cell units used in the first embodiment. It has become.
In the present embodiment, as shown in FIG. 13, a cylindrical support that internally forms a fuel gas flow path 88 that is an internal passage, a fuel electrode layer 203, a reaction suppression layer 204, an electrolyte layer 205, The air electrode catalyst layer 206, the air electrode layer 207, and an interconnector 208 for connecting adjacent cells in series are provided. The support in this embodiment is composed of a support 202 on which no upstream shift reforming metal catalyst is disposed and a support 201 on which a downstream shift reforming metal catalyst is disposed. As a result, a shift reaction does not occur as much as possible in the upstream of the fuel gas passage, and hydrogen is generated by performing a shift reaction in the downstream to provide a fuel for power generation. In particular, in the horizontally-striped fuel cell as in the present embodiment, the cells are divided and arranged in the extending direction of the fuel gas channel 88, and the current taken out from one fuel cell unit is the fuel gas channel. Since the cells flow from the upstream to the downstream of the 88, the same current is supplied to the cell that generates power in the state where hydrogen is abundant on the upstream side and the downstream cell that has reduced the amount of hydrogen used for power generation. Electricity must be generated to flow, and a large burden is placed on the cells that have generated the same power in an environment with a small amount of hydrogen. In the present embodiment, by generating hydrogen and making up for it downstream, it is possible to suppress the influence on the cells arranged downstream due to fuel depletion.
Further, in the present embodiment, the shift reforming metal catalyst is nickel, and the nickel is positioned on the downstream side of the support and at the position where the most downstream fuel electrode exists, with the fuel electrode sandwiched between the support electrode and the fuel electrode. The shift reforming metal catalyst is arranged to face each other.

  As mentioned above, although one Embodiment of this invention was described, various changes can be added to Embodiment mentioned above in the range which can achieve the objective of this invention.

DESCRIPTION OF SYMBOLS 1 Solid oxide fuel cell 2 Fuel cell module 4 Auxiliary machine unit 7 Heat insulating material (outer heat insulating material)
8 Case 10 Power generation chamber 12 Fuel cell assembly 14 Fuel cell stack 16 Fuel cell unit (solid oxide fuel cell)
18 Combustion chamber 20 Reformer 20a Evaporating section (evaporating chamber)
20b reforming part 21 current plate (partition wall)
21a Opening 21b Exhaust passage 21c Gas retention space 22 Air heat exchanger (heat exchanger for power generation oxidant gas)
23 Heat insulation material for evaporation chamber (heat insulation layer for evaporation chamber temperature rise)
24 Water supply source 26 Pure water tank 28 Water flow rate adjustment unit (water supply means)
30 Fuel supply source 38 Fuel flow rate adjustment unit (fuel supply means)
40 Air supply source 44 Reforming air flow rate adjusting unit (reforming oxidant gas supply means)
45 Air flow adjustment unit for power generation (oxidant gas supply means for power generation)
46 1st heater 48 2nd heater 50 Hot water production apparatus (heat exchanger for exhaust heat recovery)
52 Control box 54 Inverter 60 Pure water introduction pipe 62 Reformed gas introduction pipe 66 Manifold (dispersion chamber)
70 Combustion gas piping 72 Power generation air flow path 74 Power generation air introduction pipe 76 Communication flow path 76 Outlet port 77 Power generation air supply path 77a Air outlet 82 Exhaust gas discharge pipe 83 Ignition device (ignition means)
84 Fuel cell 86 Inner electrode terminal 88 Fuel gas flow path (internal passage)
89 Support 90 Inner electrode layer (fuel electrode)
92 Outer electrode layer 94 Electrolyte layer 110 Control unit (control means)
110a Ignition determination means 112 Operation device 114 Display device 116 Alarm device 126 Power state detection sensor (demand power detection means)
132 Fuel flow sensor (fuel supply detection sensor)
138 Pressure sensor (reformer pressure sensor)
142 Power generation chamber temperature sensor (temperature detection means)
148 Reformer temperature sensor 150 Outside air temperature sensor 201 Support 202 provided with shift reforming metal catalyst Support 202 not provided with shift reforming metal catalyst 203 Fuel electrode layer 204 Reaction suppression layer 205 Electrolyte layer 206 Air electrode Catalyst layer 207 Air electrode layer 208 Interconnector

Claims (10)

Solid oxide comprising a fuel cell stack in which at least two fuel cell units each including a cell comprising at least a cathode electrode, a solid electrolyte and an anode electrode are electrically connected to a cylindrical support surface having no electrical conductivity Type fuel cell device,
A fuel cell module in which the fuel cell stack is housed;
A reformer capable of generating hydrogen by a steam reforming reaction that chemically reacts fuel and steam;
An evaporator for evaporating the supplied steam reforming water;
Fuel supply means for supplying the fuel reformed by the reformer by supplying fuel to the reformer, and feeding the fuel cell stack;
Water supply means for supplying reforming water to the evaporator;
Power generation oxidant gas supply means for supplying power generation oxidant gas to the fuel cell stack;
Control means for controlling the fuel cell stack to generate power;
Have
A fuel gas passage through which fuel gas passes is formed inside the support of the fuel cell unit, and hydrogen can be generated in the fuel gas passage by a shift reforming reaction in which water vapor and carbon monoxide are reacted. A shift reforming metal catalyst is disposed, and the shift reforming metal catalyst is disposed so as to be more downstream than the upstream side near the reformer side of the fuel gas passage. A solid oxide fuel cell device.   The solid oxide fuel cell device according to claim 1, wherein the fuel cell stack is operated at a temperature during power generation of 700 ° C. or lower.   The downstream side of the support on which the shift reforming metal catalyst is disposed, the fuel electrode and the shift reforming metal catalyst are arranged to face each other with the support interposed therebetween. 3. The solid oxide fuel cell device according to 1 or 2.   The solid oxide fuel according to any one of claims 1 to 3, wherein the shift reforming metal catalyst is disposed at least at a position downstream of the support and at the most downstream fuel electrode. Battery device.   The solid oxide fuel cell device according to any one of claims 1 to 4, wherein the shift reforming metal catalyst is disposed not on the upstream side of the support but on the downstream side thereof. .   The solid oxide fuel cell device according to claim 5, wherein the shift reforming metal catalyst is not located in an intermediate region of the support but is arranged only on the downstream side.   The said support body is comprised from the porous nonelectroconductive material, and is shape | molded so that the metal catalyst for shift reforming may be exposed in this porous body. Solid oxide fuel cell device.   The shift reforming metal catalyst is disposed so that the shift reforming metal catalyst is exposed only on the fuel gas passage side of the support without exposing the shift reforming metal catalyst on the fuel electrode side of the support. 8. The solid oxide fuel cell device according to any one of 7 above.   The metal member which radiates the heat accompanying a shift reforming reaction is provided in the most downstream part of the fuel cell unit, and the exhaust passage is constituted by the member. Solid oxide fuel cell device.   The solid oxide fuel cell device according to claim 7, wherein the shift reforming metal catalyst is Ni, and is molded so that Ni is exposed only in the porous body of the downstream support.

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