JP7263212B2 - Fuel cell module and fluid supply device used therefor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fuel cell module, and more particularly to a fuel cell module that generates electricity by reacting supplied fuel gas and oxidant gas, and a fluid supply device used therein.

Japanese Patent Laying-Open No. 2017-50192 (Patent Document 1) describes a fuel cell module. This fuel cell module includes a fuel cell stack, a combustor, and a reformer, which are housed in a housing. In the fuel cell module described in Patent Document 1, the fuel cell stack is a laminated fuel cell stack formed by stacking a plurality of fuel cells, and each fuel cell is composed of an oxide ion conductor. It is constructed by providing a cathode electrode and an anode electrode on both sides of a plate-like electrolyte, respectively. A cathode separator and an anode separator are arranged between each fuel cell. Furthermore, the cathode separator is formed with an oxidant gas channel for supplying the oxidant gas to the cathode electrode, and the anode separator is formed with a fuel gas channel for supplying the fuel gas to the anode electrode.

A plurality of fuel cells, cathode separators, and anode separators stacked in this way are sandwiched between the upper end plate and the lower end plate from both ends, and are pressed and fixed in the stacking direction. Further, the lower end plate is provided with an oxidizing gas inlet for supplying oxidizing gas to each fuel cell and a fuel gas inlet for supplying fuel gas to each fuel cell. The lower end plate further includes an oxidant gas outlet for discharging the remaining oxidant gas that is supplied to the cathode electrode of each fuel cell and not used for power generation, and an oxidant gas outlet that is supplied to the anode electrode of each fuel cell, A fuel gas outlet is provided for discharging the remaining fuel gas that has not been used for power generation.

The remaining fuel gas that has flowed out from the fuel gas outlet and the remaining oxidant gas that has flowed out from the oxidant gas outlet are guided to a combustor disposed within the housing, where they are combusted. Combustion gas generated in the combustor is guided into combustion gas passages arranged on both side surfaces of the fuel cell stack and sprayed onto both side surfaces of the fuel cell stack through combustion gas outlets. As a result, the temperature of the fuel cell stack is raised to a temperature at which power generation reaction is possible. As described above, in the fuel cell module described in Patent Document 1, the remaining fuel gas is burned with the remaining oxidant gas in the combustor arranged in the housing, and the fuel cell stack is driven by the generated combustion gas. Direct heating is used to efficiently raise the temperature of the fuel cell stack to a temperature at which power generation reaction is possible, and that temperature is maintained.

JP 2017-50192 A

However, in the fuel cell module described in Patent Document 1, the fuel cell stack inside the housing is heated not only by the combustion gas generated in the combustor, but also by the radiant heat from the combustor itself, which heats up to an extremely high temperature. As a result, the fuel cell stack tends to have temperature unevenness, making it difficult to heat the fuel cell stack uniformly. When temperature unevenness occurs in the fuel cell stack, power generation efficiency is lowered, and each fuel cell may be deteriorated, resulting in a shortened useful life.

In addition, even when the fuel cell stack is heated by radiant heat radiated from the combustor, etc., by setting the flow of the combustion gas so as to offset the temperature unevenness caused by the radiant heat, etc., the fuel cell It is conceivable to bring the temperature of the cell stack closer to uniformity. However, in a fuel cell module in which temperature unevenness is offset by the flow of combustion gas in this way, the layout of the combustor, reformer, fuel cell stack, etc. in the housing may be changed, or their dimensions and shapes may be changed. If changed, there is a possibility that the flow of combustion gas inside the housing and the direction of radiant heat will change, causing temperature unevenness. Therefore, in the fuel cell module described in Patent Document 1, it is necessary to design the flow of combustion gas inside the housing specifically for the fuel cell stack and the combustor accommodated in the housing. That is, even if there is a slight change in the specifications of the combustor or the like housed in the housing, it is necessary to redo thermal simulations and prototypes in order to avoid temperature variations in the fuel cell stack.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and provides a fuel cell module capable of sufficiently uniformizing the temperature of a fuel cell stack and a fluid supply apparatus used therein. It is intended to

In order to solve the above-described problems, the present invention provides a fuel cell module that generates power by reacting supplied fuel gas and oxidant gas, the fuel cell stack comprising a plurality of fuel cells; A reformer that reforms the raw fuel gas to generate a fuel gas containing hydrogen and supplies it to the fuel cell stack, and burns the residual fuel gas that is not used for power generation in the fuel cell stack, It has a combustor that heats the reformer and a housing that has a space inside that accommodates the combustor. The housing is arranged above the fuel cell stack, and the housing and the fuel cell stack are separated. It is characterized by being arranged

In the present invention configured as described above, a fuel cell stack and a housing arranged above the fuel cell stack are provided, and the combustor is accommodated in the housing. The reformer reforms the raw fuel gas to generate fuel gas. The reformed fuel gas is supplied to the fuel cell stack. Residual fuel gas left in the fuel cell stack without being used for power generation is discharged to the housing side. The residual fuel gas is combusted in a combustor within the housing to heat the reformer.

According to the present invention configured as described above, the housing is arranged above the fuel cell stack with a space therebetween. Therefore, radiant heat emitted from the combustor or the like is blocked by the housing, and the fuel cell stack substantially exchanges heat only through the fluid flowing between the fuel cell stack and the housing. Therefore, the fuel cell stack does not have temperature variations due to radiant heat radiated from the combustor or the like. In addition, since the fuel cell stack substantially exchanges heat only through the fluid, the temperature distribution of the fuel cell stack is defined by the temperature and flow rate of the supplied fluid, and the reformer in the housing, The temperature distribution of the fuel cell stack is not affected by changes in the layout of the combustor and the like. Therefore, the fuel cell stack and the reformer, combustor, etc. in the housing can be designed independently, and the degree of freedom in designing the reformer, combustor, etc. can be increased. In addition, since the housing containing the combustor is spaced apart from the fuel cell stack, one type of housing can be used in general in combination with various fuel cell stacks. can be lowered.

In the present invention, the fuel cell preferably further comprises an evaporator for generating steam used for steam reforming in the reformer, and the reformer and evaporator are arranged above the fuel cell stack or combustor. It is

In the present invention, the reformer is preferably housed in the housing.

Preferably, the present invention further comprises an evaporator for generating steam used for steam reforming in the reformer, and the evaporator is arranged above the housing.

In the present invention, the housing is preferably provided with a heat exchanger for heating the oxidant gas used for power generation.

In the present invention, the heat exchanger is preferably provided on the lower surface of the housing.

In the present invention, preferably, the pipe for supplying the oxidant gas to the heat exchanger is further connected to the upper surface of the housing.

In the present invention, preferably, there are further passages for supplying the fuel gas and the oxidant gas from the housing to the fuel cell stack, and passages from the fuel cell stack to the housing for residual fuel gas and remaining unused for power generation. Passages for returning residual oxidant gas are connected to opposite surfaces of the housing and the fuel cell stack.

According to the fuel cell module of the present invention and the fluid supply device used therein, the temperature of the fuel cell stack can be made sufficiently uniform.

1 is a diagram showing a schematic configuration of an entire fuel cell module according to an embodiment of the invention; FIG. 1 is a perspective view showing the entire fuel cell module according to an embodiment of the present invention; FIG. 1 is a full cross-sectional view of a fuel cell module according to an embodiment of the invention; FIG. FIG. 4 is a cross-sectional view of a fuel cell module according to an embodiment of the invention, taken along line IV-IV in FIG. 3; FIG. 4 is a cross-sectional view of a fuel cell module according to an embodiment of the invention, taken along line VV in FIG. 3; FIG. 4 is a cross-sectional view of a fuel cell module according to an embodiment of the invention, taken along line VI-VI in FIG. 3;

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.
FIG. 1 is a diagram showing a schematic configuration of the entire fuel cell module according to an embodiment of the present invention.

<Schematic configuration and action of fuel cell module>
As shown in FIG. 1, a fuel cell module 1 according to an embodiment of the present invention includes a fuel cell stack 2 that performs a power generation reaction, a fuel gas obtained by reforming raw fuel gas, and a heating and a fluid supply device 4 for supplying air, which is an oxidant gas.

The fluid supply device 4 also includes a housing 6 , which is vertically arranged above the fuel cell stack 2 . The fuel cell stack 2 and the housing 6 are surrounded by a heat insulating material 8, and are also provided between the fuel cell stack 2 and the housing 6, so that the fuel cell stack 2 can be 6 (fluid supply device 4) is thermally isolated. The heat insulating material 8 surrounding the fuel cell stack 2 and the housing 6 constitutes the outermost surface of the fuel cell module 1. Even if a metal container or the like covering the outside of the heat insulating material 8 is provided, Good, but need not be provided. A reformer 36 and a combustor 38 are housed in a space sealed by the housing 6 .
In addition, in FIG. 1, although the heat insulating material 8 is described as one piece, it may be composed of a plurality of heat insulating materials. For example, the heat insulating material surrounding the fuel cell stack 2 and the housing 6 and the heat insulating material provided between the fuel cell stack 2 and the housing 6 may be different heat insulating materials.
Furthermore, the heat insulating material may be used by combining a plurality of members having different heat insulating performances, and the method of stacking and arranging the members can be appropriately designed according to the required specifications.
Moreover, the heat insulating material provided between the fuel cell stack 2 and the housing 6 does not necessarily have to completely cover the space between the fuel cell stack 2 and the housing 6, and at least partially It is effective by arranging it.

The reformer 36 is configured to steam-reform the raw fuel gas supplied from the outside of the fluid supply device 4 to generate a hydrogen-rich fuel gas. The fuel gas produced in the reformer 36 is sent to the fuel cell stack 2 and used in the fuel cell stack 2 for power generation. This fuel gas is supplied to the fuel cell stack 2 through a fuel supply passage 12 extending between the housing 6 of the fluid supply device 4 and the fuel cell stack 2 . Here, since the housing 6 of the fluid supply device 4 is surrounded by the heat insulating material 8 , the fuel supply passage 12 for supplying the fuel gas extends through the heat insulating material 8 to the fuel cell stack 2 .

The combustor 38 is configured to burn residual fuel that remains in the fuel cell stack 2 without being used for power generation. Fuel remaining in the fuel cell stack 2 without being used for power generation is discharged to the housing 6 side through a fuel discharge passage 14 extending between the housing 6 of the fluid supply device 4 and the fuel cell stack 2 . This fuel discharge passage 14 also extends from the fuel cell stack 2 to the fluid supply device 4 through the heat insulating material 8 surrounding the housing 6 of the fluid supply device 4 . The residual fuel discharged to the housing 6 side is combusted by the combustor 38 accommodated in the housing 6 to heat the reformer 36 arranged above the combustor 38 . As a result, a reforming catalyst (not shown) in the reformer 36 is heated to a temperature at which steam reforming is possible.

On the other hand, air, which is an oxidizing gas for power generation, is also supplied from the outside to the fluid supply device 4, where it is heated by the combustion heat of the combustor 38 and supplied to the fuel cell stack 2 in a high temperature state. . The fuel cell stack 2 is heated to a temperature at which power generation reaction is possible mainly by the heat of the power generation air heated to a high temperature. The air for power generation heated in the fluid supply device 4 is supplied to the fuel cell stack 2 through the oxidant gas supply passage 16 extending from the housing 6 . This oxygen-containing gas supply passage 16 also penetrates the heat insulating material 8 surrounding the housing 6 of the fluid supply device 4 and extends from the fluid supply device 4 to the fuel cell stack 2 .

Moreover, the remaining air that has been supplied to the fuel cell stack 2 and has not been used for power generation is discharged to the housing 6 side through the oxidant gas discharge passage 18 . This oxygen-containing gas discharge passage 18 also extends from the fuel cell stack 2 to the fluid supply device 4 through the heat insulating material 8 surrounding the housing 6 of the fluid supply device 4 . The residual air discharged to the housing 6 side is used for combustion in the combustor 38 inside the housing 6 . Combustion gas generated by combustion is discharged from the fluid supply device 4 as exhaust gas.

Thus, in the fuel cell module 1 of the embodiment of the present invention, residual fuel gas is combusted with residual air in the combustor 38 of the fluid supply device 4, and the reformer 36 is heated by the combustion heat. On the other hand, the reformer 36 and the combustor 38 are accommodated within the housing 6 of the fluid supply device 4 , and the housing 6 is thermally separated from the fuel cell stack 2 by the heat insulating material 8 . Therefore, the fuel cell stack 2 is substantially not directly heated by the combustion heat of the residual fuel. That is, the heat transfer between the fluid supply device 4 (housing 6) side and the fuel cell stack 2 is substantially performed only by the fluid flowing between them, and the radiant heat radiated from the combustor 38 etc. For example, the fuel cell stack 2 is not directly heated. Therefore, the temperature of the fuel cell stack 2 can be substantially defined only by the flow rate and temperature of the fluid supplied thereto.

The devices used together with the fuel cell module include an evaporator that generates steam for steam reforming, a desulfurizer that removes the sulfur component contained in the raw fuel gas, and a combustor that removes carbon monoxide from the exhaust gas. Catalytic devices, etc., can also be accommodated within the housing. Alternatively, these devices can be placed outside the housing and covered with thermal insulation and heated by the heat of the exhaust gases exiting the housing.

Next, the configuration of the fuel cell module according to the embodiment of the present invention will be described in detail with reference to FIGS. 2 to 6. FIG.
FIG. 2 is a perspective view showing the entire fuel cell module according to the embodiment of the invention. FIG. 3 is a full cross-sectional view of a fuel cell module according to an embodiment of the invention. 4 is a cross-sectional view along the IV-IV line in FIG. 3, FIG. 5 is a cross-sectional view along the VV line in FIG. 3, and FIG. 6 is a cross-sectional view along the VI-VI line in FIG. It is a diagram. In FIG. 2, a heat insulating material surrounding the fuel cell stack and the like is omitted.

<Overall Configuration of Fuel Cell Module>
As shown in FIG. 2, the fuel cell module 1 according to the embodiment of the present invention includes a fuel cell stack 2 that performs a power generation reaction, a fuel gas obtained by reforming raw fuel gas, and a heated fuel gas. and a fluid supply device 4 for supplying air, which is an oxidant gas. The fluid supply device 4 is composed of an evaporator 4a and a reformer/heater 4b. The evaporator 4a is configured to evaporate the supplied water to generate steam and to mix the steam with the raw fuel gas. The gas is steam-reformed to generate a hydrogen-containing fuel gas, which is supplied to the fuel cell stack 2 .

Further, the reformer/heater 4b is covered with a substantially rectangular parallelepiped metal housing 6, and the fuel cell stack 2, the housing 6 of the reformer/heater 4b arranged above it, and the evaporator 4a. are arranged vertically. The fuel cell stack 2, the housing 6, and the evaporator 4a are each surrounded by a heat insulating material 8, so that the fuel cell stack 2 is thermally isolated from the housing 6 and the evaporator 4a.

<Structure of fuel cell stack>
As shown in FIGS. 2 and 3, in this embodiment, the fuel cell stack 2 is a flat plate cell stack, and is constructed by stacking a plurality of rectangular flat plate fuel cells 2a. That is, each fuel cell 2a is constructed by providing electrodes of a fuel electrode and an air electrode (oxidant gas electrode) on both sides of a plate-like electrolyte made of an oxide ion conductor. Separators are arranged between the cells 2a (not shown). A top end plate 10a is arranged at the upper end of the plurality of stacked fuel cells 2a, and a bottom end plate 10b is arranged at the lower end. Inside the fuel cell stack 2 obtained by stacking a plurality of fuel cells 2a in this way, a fuel gas supply passage (not shown) for supplying fuel gas to each fuel cell 2a, An oxidizing gas supply passage (not shown) is formed for supplying air, which is an oxidizing gas. Two bus bars 2b extend from the top and bottom of the fuel cell stack 2 for taking out the generated power.

Further, a fuel supply passage 12, a fuel discharge passage 14, an oxidant gas supply passage 16, and an oxidant gas discharge passage 18 are connected to the top end plate 10a of the fuel cell stack 2, respectively. These four passages extend into the space sandwiched between the fuel cell stack 2 and the housing 6 of the reformer/heater 4b. That is, these passages extend upward from the upper surface of the top end plate 10a of the fuel cell stack 2 and are connected to the bottom surface, which is a single surface, of the housing 6 disposed above the fuel cell stack 2. . Therefore, the fuel supply passage 12, the fuel discharge passage 14, the oxidant gas supply passage 16, and the oxidant gas discharge passage 18 pass through the heat insulating material 8 arranged between the fuel cell stack 2 and the housing 6. It's getting longer. The housing 6 of the reformer/heater 4b is connected to the fuel cell stack 2 by these four passages (the fuel supply passage 12, the fuel discharge passage 14, the oxidant gas supply passage 16, and the oxidant gas discharge passage). 18) is connected and supported only by

The fuel supply passage 12 and the fuel discharge passage 14 are arranged side by side in the vicinity of one short side of the top end plate 10a and extend linearly vertically upward. The fuel gas reformed in the reformer/heater 4b is supplied to the fuel cell stack 2 through the fuel supply passage 12, and passes through the fuel gas supply passage (not shown) in the fuel cell stack 2. It is distributed to each fuel cell 2a. Residual fuel gas not used for power generation in each fuel cell 2a was collected through a fuel gas discharge passage (not shown) in the fuel cell stack 2 and attached to the top end plate 10a. The fuel is discharged through the fuel discharge passage 14 to the reformer/heater 4b.

As shown in FIGS. 3 and 4, the oxidizing gas supply passage 16 and the oxidizing gas discharge passage 18 are arranged side by side near one long side of the top end plate 10a, extend vertically upward, and then extend inward. It bends 90 degrees toward and extends horizontally, and further bends 90 degrees and extends vertically upward. The upper ends of the oxidizing gas supply passage 16 and the oxidizing gas discharge passage 18 are connected to the bottom surface of the housing 6 of the reformer/heater 4b so as to be aligned along the longitudinal central axis thereof.

The air heated in the reformer/heater 4b is supplied to the fuel cell stack 2 through the oxidizing gas supply passage 16, and passes through the oxidizing gas supply passage (not shown) in the fuel cell stack 2. distributed to each fuel cell 2a. Residual air not used for power generation in each fuel cell 2a was collected through an oxidant gas discharge passage (not shown) in the fuel cell stack 2 and attached to the top end plate 10a. It is discharged to the reformer/heater 4b through the oxidant gas discharge passage 18. As shown in FIG.

Further, as described above, the position where the oxidant gas supply passage 16 and the oxidant gas discharge passage 18 are connected to the bottom surface of the housing 6 and the position where these passages are connected to the fuel cell stack 2 are shown in top view. , the fuel cell stack 2 side and the housing 6 side can be connected by curving those passages in the space between the housing 6 and the fuel cell stack 2 . Therefore, various fuel cell stacks 2 can be connected to a single housing 6 (fluid supply device 4) by appropriately changing the connecting passages. In addition, since each passage extends into the space sandwiched between the housing 6 and the fuel cell stack 2, the fuel supply passage 12, the fuel discharge passage 14, and the oxidant gas supply can be realized without increasing the occupied floor space. A passageway 16 and an oxidant gas discharge passageway 18 may be provided.

Furthermore, the fuel supply passage 12, the fuel discharge passage 14, the oxidizing gas supply passage 16, and the oxidizing gas discharge passage 18 each have a connecting structure using a piping screw, and the connecting nut is loosened. Therefore, it is configured to be separable. Thus, the fuel supply passage 12, the fuel discharge passage 14, the oxidant gas supply passage 16, and the oxidant gas discharge passage 18 are detachably connected to the housing 6 of the reformer/heater 4b. Alternatively, some or all of these four passages may be configured to extend from the bottom surface of housing 6 and these passages may be detachably connected to fuel cell stack 2 .

<Configuration of evaporator>
Next, the structure of the evaporator 4a will be described with reference to FIGS. 2 and 3. FIG. As shown in FIG. 2, the evaporator 4a includes a water supply pipe 20 for supplying water, a raw fuel gas supply pipe 22 for supplying raw fuel gas, and an exhaust gas for discharging exhaust gas. A discharge pipe 24 is connected. Further, the housing 6 of the reformer/heater 4b and the evaporator 4a outside thereof are connected by a pipe, and this pipe is an exhaust gas pipe for supplying the exhaust gas from the reformer/heater 4b to the evaporator 4a. 26 and a mixed gas conduit 28 arranged inside (FIG. 3). The mixed gas conduit 28 is configured to introduce a mixer obtained by mixing the steam generated in the evaporator 4a and the raw fuel gas supplied to the evaporator 4a into the reformer/heater 4b. An electric heater 29 for auxiliary heating of the evaporator 4a is wound around three sides around the evaporator 4a.

As shown in FIG. 3, the evaporator 4a is formed of a metal plate in the shape of a rectangular parallelepiped box, and has therein an evaporating chamber 30a, a mixing chamber 30b, and an exhaust gas chamber 30c. The evaporation chamber 30a is a thin space formed directly below the ceiling surface of the evaporator 4a, and the water is supplied from the water supply pipe 20 and the raw fuel gas supply pipe 22 connected to the ceiling surface of the evaporator 4a. Water and raw fuel gas are configured to flow into the evaporation chamber 30a.

The mixing chamber 30b is formed as a space that communicates with the downstream side of the evaporation chamber 30a via a narrow passage 30d. The steam generated in the evaporation chamber 30a and the raw fuel gas supplied into the evaporation chamber 30a are mixed by flowing into the mixing chamber 30b through the narrow passage 30d. A mixed gas conduit 28 is connected to the bottom surface of the mixing chamber 30b, and the steam and raw fuel gas mixed in the mixing chamber 30b are introduced into the reformer/heater 4b through the mixed gas conduit 28. .

The exhaust gas chamber 30c is a space provided under the evaporator 4a, and is configured such that the exhaust gas flows through the exhaust gas pipe 26 connected to the bottom surface of the evaporator 4a. The exhaust gas that has flowed into the exhaust gas chamber 30c heats the floor surface of the evaporation chamber 30a provided above the exhaust gas chamber 30c and is discharged from the exhaust gas discharge pipe 24 connected to the side end of the evaporator 4a. be done. The water supplied to the evaporation chamber 30a is evaporated by heating the floor surface of the evaporation chamber 30a by the exhaust gas flowing in the exhaust gas chamber 30c.

The downstream side of the exhaust gas chamber 30c is made thin so that the inflowing exhaust gas flows along the floor surface of the evaporation chamber 30a (the ceiling surface of the exhaust gas chamber 30c). Heat transfer fins 30e are arranged in this thin space so that the heat of the exhaust gas flowing through the exhaust gas chamber 30c is efficiently transferred to the floor surface of the evaporation chamber 30a. Thus, the exhaust gas flowing from the exhaust gas pipe 26 connected to one end of the exhaust gas chamber 30c flows toward the exhaust gas discharge pipe 24 connected to the other end (from left to right in FIG. 3). On the other hand, the water supplied from the water supply pipe 20 connected to the end of the evaporation chamber 30a on the side of the exhaust gas discharge pipe 24 is evaporated in the evaporation chamber 30a toward the other end (Fig. 3 from right to left). In this manner, since the water vapor and the exhaust gas flowing in the evaporator 4a flow in opposite directions, counter-flow heat exchange is performed between them, and heat exchange is efficiently performed.

<Structure of reformer/heater>
Next, the structure of the reformer/heater 4b will be described with reference to FIGS. 2 to 6. FIG.
As shown in FIG. 2, the reformer/heater 4b is formed in a rectangular parallelepiped box shape surrounded by a metal housing 6, and air, which is an oxidizing gas for power generation, is supplied to the upper surface of the reformer/heater 4b. An air supply pipe 32 is connected for As described above, the upper surface of the housing 6 has a double pipe of the exhaust gas pipe 26 and the mixed gas pipe 28 (FIG. 3), and the bottom has the fuel supply passage 12, the fuel discharge passage 14, and the oxidant gas supply passage. 16, and an oxidant gas discharge passage 18 are connected. A ceramic heater 34 for ignition is attached to one side surface of the housing 6 .

The reformer/heater 4b steam-reforms the mixed gas introduced from the mixed gas conduit 28 to generate a fuel gas, supplies the fuel gas to the fuel cell stack 2 through the fuel supply passage 12, and supplies the fuel gas to the air supply pipe. The air introduced through 32 is heated and supplied to the fuel cell stack 2 through the oxidant gas supply passage 16 . In addition, the residual fuel gas and residual air (residual oxidant gas) that have not been used for power generation in the fuel cell stack 2 are reformed and heated through the fuel discharge passage 14 and the oxidant gas discharge passage 18, respectively. It is discharged to the container 4b. The residual fuel gas and residual air discharged through the fuel discharge passage 14 and the oxygen-containing gas discharge passage 18 are combusted in the reformer/heater 4b, and the combustion heat converts the air introduced from the air supply pipe 32 into to heat. Combustion gas generated by combustion is introduced into the evaporator 4a as exhaust gas via an exhaust gas pipe 26. As shown in FIG.

Next, the internal structure of the reformer/heater 4b will be described with reference to FIGS. 3 to 6. FIG.
As shown in FIG. 3, inside the housing 6 that forms the reformer/heater 4b, a closed space that accommodates the reformer 36 and the combustor 38 is formed.

The reformer 36 is a metal annular container having a rectangular cross section when viewed from the top and a rectangular opening in the center. The other end is connected to a fuel supply passage 12 (FIG. 5) through which the reformed fuel gas flows out. The mixed gas conduit 28 extending from the evaporator 4a into the housing 6 is bent 90 degrees in the housing 6, extends horizontally, and then bends vertically downward by 90 degrees to reach the ceiling surface of the reformer 36. It is connected. The fuel supply passage 12 is connected to the bottom surface of the reformer 36 at the end opposite to the mixed gas conduit 28, extends vertically downward through the bottom surface of the housing 6, and is connected to the fuel cell stack 2. ing. The reformer 36 is filled with a reforming catalyst 36a. The mixed gas of raw fuel gas and steam flowing from the mixed gas conduit 28 is steam-reformed by coming into contact with the reforming catalyst 36a to generate fuel gas rich in hydrogen gas. The fuel gas steam-reformed in the reformer 36 flows into the fuel supply passage 12 and is supplied to the fuel cell stack 2 .

The combustor 38 is provided inside the bottom wall surface of the housing 6 adjacent to the fuel cell stack 2, and discharges residual fuel gas discharged through the fuel discharge passage 14 through the oxidant gas discharge passage 18. It is arranged to be combusted by the residual air exhausted by the

As shown in FIG. 6, the combustor 38 has a residual fuel gas manifold 38a, a residual fuel gas distribution pipe 38b connected thereto, and a residual air distribution plate 38c for distributing the residual air within the housing 6. .
The residual fuel gas manifold 38a is a box-shaped member attached to the bottom wall surface of one end of the housing 6 so that the residual fuel gas from the fuel discharge passage 14 connected to the bottom wall surface of the housing 6 flows into the interior. is configured to

Residual fuel gas distribution pipes 38b are composed of pipes of circular cross-section, and these pipes extend in parallel from residual fuel gas manifold 38a in the longitudinal direction of housing 6, and in the other end of housing 6 in the lateral direction. joined by an extending pipe. A large number of pores are provided on the upper surface of the pipe constituting the residual fuel gas distribution pipe 38b. configured to erupt.

The residual air distribution plate 38c is made of an elongated metal plate bent into a trapezoidal cross section (FIG. 4) and attached to the center of the bottom wall surface of the housing 6 so as to extend longitudinally. The oxygen-containing gas discharge passage 18 connected to the bottom wall surface of the housing 6 communicates with the trapezoidal cross-sectional space surrounded by the residual air dispersion plate 38 c and the bottom wall surface of the housing 6 . In addition, a large number of pores are formed on the slopes on both sides of the residual air distribution plate 38c, and the residual air that has flowed in from the oxidizing gas discharge passage 18 is injected into the housing 6 through these pores and dispersed. be done.

As shown in FIGS. 3 and 6, a ceramic heater 34 is attached to the side wall of the housing 6, and its tip extends to the center of the confluence of the residual fuel gas distribution pipe 38b. When the fuel cell module 1 is started, the residual fuel gas is blown out from the pores of the residual fuel gas distribution pipe 38b, and the residual air is blown out from the pores of the residual air distribution plate 38c. By energizing, it is possible to ignite the ejected residual fuel gas. Thereby, the reformer 36 arranged above the combustor 38 within the housing 6 can be heated. (When the fuel cell module 1 is started, the temperature of the reformer 36 is not raised, so no reforming reaction occurs in the reformer 36, and power generation by the fuel cell stack 2 is also being performed. do not have.)

<Configuration of oxidant gas heat exchanger>
Next, the oxidant gas heat exchanger provided in the reformer/heater 4b will be described with reference to FIGS. 3 and 4. FIG.
As shown in FIGS. 3 and 4, a portion of the wall surface of the housing 6 has a double wall structure, and the combustor 38 is generated by flowing air for power generation inside the double wall. The heated combustion gas heats the air flowing inside. That is, a portion of the upper surface, a portion of the longitudinal side wall surface, and a portion of the bottom wall surface of the housing 6 are formed of two metal plates, an inner wall plate 6a and an outer wall plate 6b. Heat transfer fins 40 are arranged between the inner wall plate 6a and the outer wall plate 6b so that the heat of the inner wall plate 6a is efficiently transferred to the space between the inner wall plate 6a and the outer wall plate 6b. there is Therefore, the inner wall plate 6a, the outer wall plate 6b, and the heat transfer fins 40 heat the supplied air, which is the oxidant gas, by the combustion gas generated by the combustor 38, and supply it to the fuel cell stack 2. It functions as an oxidant gas heat exchanger.

The air supplied from the air supply pipe 32 flows into the space between the inner wall plate 6a and the outer wall plate 6b that constitute the upper wall surface of the housing 6 (FIG. 3), and spreads in the lateral direction of the housing 6 from there. It flows into the space between the inner wall plate 6a and the outer wall plate 6b that constitute the side walls of the housing 6 (Fig. 4). The air that has flowed into the side wall surface of the housing 6 descends and flows into the space between the inner wall plate 6a and the outer wall plate 6b that constitute the bottom wall surface of the housing 6. As shown in FIG. The air that has flowed into the bottom wall surface of the housing 6 is supplied to the fuel cell stack 2 through an oxidant gas supply passage 16 (FIG. 3) connected to the center of the bottom wall surface of the housing 6 in the width direction. Therefore, part of the upper wall surface, the side wall surface, and the bottom wall surface of the housing 6 function as oxidant gas heat exchangers, and the oxidant gas heat exchangers are provided on these wall surfaces.

<Action of fuel cell module>
Next, the operation of the fuel cell module 1 according to the embodiment of the invention will be described.
First, when the fuel cell module 1 is started, raw fuel gas is supplied to the evaporator 4a of the fluid supply device 4 through the raw fuel gas supply pipe 22, and air for power generation is supplied through the air supply pipe 32. is supplied to the reformer/heater 4 b of the fluid supply device 4 . As shown in FIG. 3, the supplied raw fuel gas passes through the evaporation chamber 30a and the mixing chamber 30b of the evaporator 4a and flows into the mixed gas conduit 28, and then into the reformer 36 of the reformer/heater 4b. flow into. In addition, since the temperature of the reformer 36 is low at the initial stage of startup of the fuel cell module 1, the reaction for reforming the raw fuel gas does not occur. The raw fuel gas that has flowed into the reformer 36 flows into the fuel cell stack 2 through the fuel supply passage 12 (FIG. 5).

On the other hand, the air supplied to the reformer/heater 4b through the air supply pipe 32 passes through the space between the inner wall plate 6a and the outer wall plate 6b of the housing 6 and the oxidant gas supply passage 16 (FIG. 5). and flows into the fuel cell stack 2. The raw fuel gas and air that have flowed into the fuel cell stack 2 pass through internal passages and are discharged to the reformer/heater 4b via the fuel discharge passage 14 and the oxidant gas discharge passage 18, respectively. It should be noted that, at the initial stage of startup of the fuel cell module 1, the temperature of the fuel cell stack 2 is low, so that the power generation reaction does not occur in the fuel cell stack 2. FIG.

The raw fuel gas that has flowed into the reformer/heater 4b through the fuel discharge passage 14 passes through the residual fuel gas manifold 38a of the combustor 38, flows into the residual fuel gas distribution pipe 38b, and is ejected from the pores. On the other hand, the air discharged to the reformer/heater 4b through the oxidant gas discharge passage 18 flows into the residual air distribution plate 38c and is jetted out from the pores. When the fuel cell module 1 is started, the ceramic heater 34 is energized, and the heat of the ceramic heater 34 ignites the raw fuel gas ejected from the pores of the residual fuel gas distribution pipe 38b. This causes combustor 38 to generate combustion heat.

When the combustor 38 is ignited, the reformer 36 arranged above it is heated, and the temperature of the reforming catalyst 36a inside rises. In addition, the combustion gas generated by the combustion heats the oxidizing gas heat exchanger constituted by the inner wall plate 6a and the outer wall plate 6b of the housing 6, thereby heating the air flowing inside. Since the heated air flows into the fuel cell stack 2 , the heat heats the fuel cell stack 2 . Here, since the housing 6 of the fluid supply device 4 is surrounded by the heat insulating material 8, the fuel cell stack 2 is hardly heated by radiant heat or the like from the housing 6, and the fuel cell stack 2 is substantially It is heated only by the fluid (air and fuel gas) supplied from the fluid supply device 4 .

Combustion gas generated in the housing 6 flows through the exhaust gas pipe 26 into the evaporator 4a as exhaust gas. The exhaust gas that has flowed into the evaporator 4a is discharged from the exhaust gas discharge pipe 24 through the exhaust gas chamber 30c. At this time, the evaporation chamber 30a provided above the exhaust gas chamber 30c is heated. Thus, the water supplied to the evaporator 4 a is heated by the combustion gases produced by the combustor 38 and supplied by the exhaust gas line 26 . After the temperature of the evaporation chamber 30a rises, the supply of water from the water supply pipe 20 is started, and steam is generated in the evaporation chamber 30a. Incidentally, when the fuel cell module 1 is activated, the electric heater 29 may be energized in order to assist the heating of the evaporation chamber 30a.

When steam is generated in the evaporation chamber 30 a , a mixed gas of raw fuel gas and steam is supplied to the reformer 36 . When the temperature of the reformer 36 rises sufficiently, the steam reforming reaction is induced by the reforming catalyst 36a, and fuel gas rich in hydrogen gas is produced from the raw fuel gas. The generated fuel gas is supplied to the fuel cell stack 2 . When the temperature of the fuel cell stack 2 rises sufficiently, the fuel gas and the air heated in the reformer/heater 4b generate power generation reaction. In a state in which the temperature of the fuel cell stack 2 has risen to a temperature at which power generation is possible, power is extracted from the fuel cell stack 2 via the bus bar 2b to start power generation.

<Effects of the fuel cell module according to the embodiment of the present invention>
According to the fuel cell module 1 of the embodiment of the present invention, the fuel cell stack 2 is arranged outside the housing 6 independently of the metal housing 6 (Fig. 2). Therefore, the fuel cell stack 2 receives heat substantially only through the fluid flowing between the fuel cell stack 2 and the housing 6 . For this reason, temperature unevenness in the fuel cell stack 2 does not occur due to radiant heat radiated from the combustor 38 or the like. Further, since the fuel cell stack 2 is substantially heated only through the fluid, the temperature distribution of the fuel cell stack 2 is defined by the temperature and flow rate of the supplied fluid, and the reformer in the housing 6 The temperature distribution of the fuel cell stack 2 is not affected by changes in the layout of the combustor 36, combustor 38, and the like. Therefore, the fuel cell stack 2, the reformer 36, the combustor 38, etc. in the housing 6 can be designed independently, and the degree of freedom in designing the reformer 36, the combustor 38, etc. is increased. can be expanded. In addition, since the housing 6 containing the reformer 36, the combustor 38, etc. is independent of the fuel cell stack 2, one type of housing can be used in combination with various fuel cell stacks. It is possible to reduce the manufacturing cost by mass production.

Further, according to the fuel cell module 1 of the present embodiment, since the fuel cell stack 2 is provided apart from the housing 6, the heat directly transmitted from the housing 6 to the fuel cell stack 2 by heat conduction is reduced. be able to. As a result, it is possible to further reduce the influence of changes in the arrangement of the reformer 36 and the combustor 38 in the housing 6 on the temperature distribution of the fuel cell stack 2 .

Furthermore, according to the fuel cell module 1 of the present embodiment, since the heat insulating material 8 is arranged in the space between the fuel cell stack 2 and the housing 6, the heat is directly transmitted between the fuel cell stack 2 and the housing 6. Heat can be further reduced. As a result, it is possible to further reduce the influence of changes in the arrangement of the reformer 36 and the combustor 38 in the housing 6 on the temperature distribution of the fuel cell stack 2 .

Further, according to the fuel cell module 1 of the present embodiment, since the fuel cell stack 2 is arranged to face one surface of the housing 6, heat is directly transmitted from the housing 6 to the fuel cell stack 2. Even if this is the case, the temperature unevenness in the fuel cell stack 2 is unlikely to occur, and the adverse effects of the heat received from the housing 6 can be further reduced.

Furthermore, according to the fuel cell module 1 of the present embodiment, the heat insulating material 8 is provided so as to surround the fuel cell stack 2 and the housing 6, respectively, so that the space between the fuel cell stack 2 and the housing 6 is completely are thermally isolated by a heat insulator 8. Therefore, heat transfer can be completely blocked except for the inflow of heat by gas passing through each passage penetrating the heat insulating material 8 .

Further, according to the fuel cell module 1 of the present embodiment, the fuel cell stack 2 and the housing 6 are arranged side by side in the vertical direction. Also, only one side of the fuel cell stack 2 is not heated, and the temperature distribution of the fuel cell stack 2 can be made more uniform.

Furthermore, according to the fuel cell module 1 of the present embodiment, since the light housing 6 is arranged above the heavy fuel cell stack 2, the fuel cell stack 2 is arranged above the housing 6. Compared to the arrangement, the fuel cell module 1 is more stable, and the upper device can be easily supported.

Further, according to the fuel cell module 1 of the present embodiment, the fuel supply passage 12 and the fuel discharge passage 14 extend into the space between the fuel cell stack 2 and the housing 6 (FIG. 1), so the occupied floor space is reduced. The fuel supply passage 12 and the fuel discharge passage 14 can be provided without widening the . Further, even when the positions to which the fuel supply passage 12 and the fuel discharge passage 14 are to be connected are different between the fuel cell stack 2 side and the housing 6 side when viewed from above, the passages are curved in the space between them. Thus, passages can be connected. Therefore, it is possible to connect various fuel cell stacks 2 having different sizes and shapes to the single housing 6 .
Furthermore, in the fuel cell module 1 of this embodiment described above, the fuel supply passage 12 and the fuel discharge passage 14 extend into the space between the fuel cell stack 2 and the housing 6. Either one may extend from the side of the fuel cell stack 2 or the housing 6 . Also, the fuel supply passage 12 and the fuel discharge passage 14 may extend from one side or one surface of the housing 6 .

Furthermore, according to the fuel cell module 1 of the present embodiment, the housing 6 has only the fuel supply passage 12 , the fuel discharge passage 14 , the oxidant gas supply passage 16 and the oxidant gas discharge passage 18 with respect to the fuel cell stack 2 . (FIG. 2), there is no need to provide a dedicated support member for supporting the housing 6, and heat transfer between the fuel cell stack 2 and the housing 6 can be prevented via the support member. can. In addition, since the fluid flows in each passage, the temperature of the passage itself is generally governed by the temperature of the fluid flowing therein, so heat dissipation through the passage due to heat conduction can be suppressed.

Further, according to the fuel cell module 1 of the present embodiment, the fuel supply passage 12, the fuel discharge passage 14, the oxidant gas supply passage 16, and the oxidant gas discharge passage 18 are detachably connected (Fig. 2). Therefore, if either the housing 6 or the fuel cell stack 2 has a problem, maintenance or replacement can be performed independently.

Furthermore, according to the fuel cell module 1 of the present embodiment, the fuel cell stack 2 is a flat plate cell stack configured by stacking a plurality of flat plate fuel cells 2a, and itself has a sealed structure. A flow path is formed inside for the fuel gas and the oxidant gas to flow. Therefore, the fluid can be easily supplied to or discharged from the housing 6 simply by connecting these flow paths and the respective passages. Thereby, the structure of the fuel cell module 1 can be simplified.

Although preferred embodiments of the present invention have been described above, various modifications can be made to the above-described embodiments. In particular, in the above-described embodiment, the reformer and the combustor are contained within the housing, and the evaporator is arranged outside the housing. can also Furthermore, the present invention can be constructed such that a desulfurizer for removing sulfur components contained in the raw fuel gas and a combustion catalyst for removing carbon monoxide and the like in the exhaust gas are accommodated in the housing. In the above-described embodiment, the oxygen-containing gas heat exchanger is integrally formed with the outer wall surface of the housing. can also Furthermore, in the above-described embodiments, the housings are arranged side by side above the fuel cell stack. It can also be placed.

REFERENCE SIGNS LIST 1 fuel cell module 2 fuel cell stack 2a fuel cell 2b bus bar 4 fluid supply device 4a evaporator 4b reformer/heater 6 housing 6a inner wall plate 6b outer wall plate 8 heat insulating material 10a top end plate 10b bottom end plate 12 fuel supply Passage 14 Fuel discharge passage 16 Oxidant gas supply passage 18 Oxidant gas discharge passage 20 Water supply pipe 22 Raw fuel gas supply pipe 24 Exhaust gas discharge pipe 26 Exhaust gas pipe 28 Mixed gas pipe 29 Electric heater 30a Evaporation chamber 30b Mixing chamber 30c exhaust gas chamber 30d passage 30e fins 32 air supply pipe 34 ceramic heater 36 reformer 36a reforming catalyst 38 combustor 38a residual fuel gas manifold 38b residual fuel gas distribution pipe 38c residual air distribution plate 40 fins

Claims (5)

A fuel cell module that generates power by reacting supplied fuel gas and oxidant gas,
a fuel cell stack comprising a plurality of fuel cells; and
a reformer that reforms the raw fuel gas to generate a fuel gas containing hydrogen and supplies the hydrogen-containing fuel gas to the fuel cell stack;
a combustor that burns residual fuel gas remaining in the fuel cell stack without being used for power generation to heat the reformer;
a housing in which a space for accommodating the combustor is formed;
has
A heat exchanger for heating the oxidant gas used for power generation is provided on the lower surface of the housing,
A fuel cell module, wherein the housing is arranged above the fuel cell stack, and the housing and the fuel cell stack are arranged apart from each other. Further, an evaporator for generating steam used for steam reforming in the reformer is provided, and the reformer and the evaporator are arranged above the fuel cell stack or the combustor. 2. The fuel cell module of claim 1. 3. The fuel cell module according to claim 1, further comprising an evaporator for generating steam used for steam reforming in said reformer, said evaporator being arranged above said housing. . 2. The fuel cell module according to claim 1, further comprising a pipe for supplying oxidizing gas to said heat exchanger connected to the upper surface of said housing. Furthermore, passages for supplying fuel gas and oxidant gas from the housing to the fuel cell stack, respectively; 5. The fuel cell module according to any one of claims 1 to 4 , wherein passages for returning chemical gases are connected to surfaces of said housing and said fuel cell stack facing each other.

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