JP6608669B2 - Fuel cell module and fuel cell system - Google Patents

Description

  Embodiments according to the present invention relate to a fuel cell module and a fuel cell system.

  Various fuel cell systems have been proposed as next-generation power generation systems. The fuel cell system includes a fuel cell module and an auxiliary device that supplies natural gas, water, or air to the fuel cell module. The fuel cell module includes a cell stack in which a plurality of fuel cells are stacked.

  As one of the fuel cells constituting the cell stack, a solid oxide fuel cell including a fuel electrode, an oxidant electrode, and a solid electrolyte is known. In the solid oxide fuel cell, a hydrogen-containing gas is supplied to the fuel electrode as a reaction gas from the cell inlet. The hydrogen-containing gas is generated by reacting the hydrocarbons in the natural gas supplied from the auxiliary equipment with steam in the reformer upstream of the solid oxide fuel cell (that is, steam reforming method). It contains hydrogen and carbon monoxide. At the fuel electrode, hydrogen and carbon monoxide in the hydrogen-containing gas react with oxide ions that have moved to the fuel electrode through the electrolyte, thereby releasing electrons. The fuel cell module generates power by the electrons. On the other hand, an oxygen-containing gas, that is, air is supplied to the oxidizer electrode as a reaction gas from the cell inlet. At the oxidant electrode, oxygen ions are generated by receiving electrons emitted from the fuel electrode. The generated oxide ions move to the fuel electrode through the electrolyte.

  The solid oxide fuel cell having such a configuration has a higher cell voltage with respect to current density and higher performance as the temperature is higher. In order to improve the performance of the solid oxide fuel cell, the fuel cell module includes a combustion chamber downstream of the cell outlet. The combustion chamber heats the cell by burning surplus reaction gas discharged from the solid oxide fuel cell. The above-described reformer is provided in the combustion chamber, and reacts natural gas and water vapor using the heat of the combustion chamber.

  Further, the solid oxide fuel cell generates heat with power generation. In order to preheat the oxygen-containing gas using this heat generation, the fuel cell module includes a gas introduction member. The gas introduction member has an oxygen-containing gas flow path facing the combustion chamber and the cell stack. In the flow path, the oxygen-containing gas sequentially flows through the combustion chamber and the side of the cell stack toward the cell inlet. During the flow process, the oxygen-containing gas is preheated by heat exchange with the combustion chamber and the cell stack. Conversely, the combustion chamber and cell stack are cooled.

  Among the plurality of solid oxide fuel cells in the cell stack, the cell disposed at the center in the stacking direction has heat input due to heat generated by power generation from the surrounding cells. On the other hand, the cells arranged at the end in the stacking direction have few surrounding cells and little heat input due to heat generated by power generation, and are close to room temperature through a heat insulating material, so that they are easily radiated. For this reason, the cell stack has a temperature distribution in which the temperature at the center in the stacking direction is high and the temperature at the end in the stacking direction is low. Due to this temperature distribution, there is a problem that the durability of the central solid oxide fuel cell is lowered.

  In order to solve such a problem, it has been proposed to make the inner dimension of the gas introduction member in the stacking direction smaller than the dimension of the cell stack in the stacking direction. By reducing the inner dimension of the gas introduction member, the oxygen-containing gas flows intensively in the center in the stacking direction. As a result, the central solid oxide fuel cell is intensively cooled with the oxygen-containing gas, and the temperature rise is suppressed.

  However, in the conventional fuel cell module, since the size of the combustion chamber is restricted by the gas introduction member, it is difficult to sufficiently mix the reaction gas discharged from the fuel cell in the combustion chamber. Thereby, there existed a problem that the combustibility of a reactive gas was bad.

JP 2010-146783 A

Fuel cell vol.12 No.1 2012 (Fuel Cell Development Information Center)

  The problem to be solved by the present invention is to provide a fuel cell module and a fuel cell system capable of improving the combustibility of the reaction gas.

  The fuel cell module according to the present embodiment includes a plurality of stacked fuel cells, and a cell stack that allows the first reaction gas and the second reaction gas to flow in a direction orthogonal to the stacking direction of the fuel cells. A combustion chamber disposed downstream of the cell stack in the flow direction of the first and second reaction gases and burning the first and second reaction gases discharged from the cell stack; A gas introduction member that faces the combustion chamber and the cell stack in a direction orthogonal to the direction and the flow direction, and sequentially introduces the first reaction gas along the combustion chamber and the cell stack. A flow path for preheating the first reaction gas and supplying the preheated first reaction gas to the cell stack at a downstream end; and the flow path, the combustion chamber, and the cell stack. Includes a gas introducing member having a partition wall cut, the upstream portion of said gas introduction member facing the combustion chamber, the outer shape width of the stacking direction is smaller than the cell stack.

It is a schematic diagram of the fuel cell system which shows 1st Embodiment. It is a schematic diagram of the fuel cell module which shows 2nd Embodiment. It is a schematic diagram of the fuel cell module which shows 3rd Embodiment. It is a schematic diagram of the fuel cell module which shows 4th Embodiment. It is a schematic diagram of the fuel cell module which shows 5th Embodiment. It is a schematic diagram of the fuel cell module which shows 6th Embodiment. It is a schematic diagram of the fuel cell module which shows 7th Embodiment. It is a schematic diagram of the fuel cell module which shows 8th Embodiment. It is a schematic diagram of the fuel cell module which shows 9th Embodiment. It is a schematic diagram of the fuel cell module which shows 10th Embodiment. It is a schematic diagram of the fuel cell module which shows 11th Embodiment. It is a figure which shows the experimental example of a fuel cell module.

  Embodiments according to the present invention will be described below with reference to the drawings. This embodiment does not limit the present invention.

(First embodiment)
First, as a first embodiment, a fuel cell module and a fuel cell system in which the outer width of the upstream portion of the gas introduction member is smaller than the outer width of the cell stack will be described. FIG. 1 is a schematic diagram of a fuel cell system 1 according to the first embodiment.

  As shown in FIG. 1, the fuel cell system 1 includes a fuel cell module 2 and a fuel supply device 31 and a blower 32 which are examples of auxiliary machines. The fuel cell module 2 includes a cell stack 21, a combustion chamber 22, and a gas introduction member 23. The fuel cell module 2 is, for example, a hot module.

(Cell stack 21)
The cell stack 21 includes a plurality of solid oxide fuel cells 211 that are examples of fuel cells, and a storage container (not shown) that stores the solid oxide fuel cells 211. Each solid oxide fuel cell 211 is stacked in the stacking direction D1. The cell stack 21 allows the oxygen-containing gas 4 that is an example of the first reaction gas and the hydrogen-containing gas 5 that is an example of the second reaction gas to flow in the flow direction D2 orthogonal to the stacking direction D1.

  Each solid oxide fuel cell 211 is erected on a manifold (not shown) in the storage container. The solid oxide fuel cells 211 adjacent in the stacking direction D1 are electrically connected to each other via a current collecting member (not shown). The storage container has a hollow structure (double wall structure) with an inner wall and an outer wall, and a gas flow path for allowing the oxygen-containing gas 4 to flow is provided between the inner wall and the outer wall. . Although not shown, each solid oxide fuel cell 211 includes a fuel electrode, an oxidant electrode, and an electrolyte. The oxidant electrode may be provided on the outer periphery of the solid oxide fuel cell 211. At both ends of the cell stack 21 in the stacking direction D1, bus bars (not shown) are provided for collecting current generated by power generation and drawing it out. The solid oxide fuel cell 211 functions at a high temperature of 500 to 1000 ° C., for example.

  The cell stack 21 is in fluid communication with the gas introduction member 23, the gas flow path in the storage container, and the blower 32 in order toward the upstream side of the oxygen-containing gas 4. The cell stack 21 is in fluid communication with a manifold, a gas flow pipe (not shown), a reformer, and a fuel supply device 31 in order toward the upstream side of the hydrogen-containing gas 5. The reformer functions at a high temperature of 400 to 700 ° C., for example, and generates the hydrogen-containing gas 5 based on the fuel 50 (natural gas or water) supplied from the fuel supply device 31.

(Combustion chamber 22)
The combustion chamber 22 is disposed downstream of the cell stack 21 in the flow direction D2. More specifically, the combustion chamber 22 is disposed above the cell stack 21 in the storage container. The combustion chamber 22 burns excess oxygen-containing gas 4 and hydrogen-containing gas 5 discharged from the cell stack 21. Combustion gas generated by the combustion is discharged to the outside of the storage container through an exhaust passage (not shown) provided in the storage container.

  In the combustion chamber 22, the above-described reformer is disposed. The reformer uses the heat of the combustion chamber 22 to generate the hydrogen-containing gas 5.

(Gas introduction member 23)
The gas introduction member 23 faces the combustion chamber 22 and the cell stack 21 in a direction D3 orthogonal to the stacking direction D1 and the flow direction D2. The gas introduction member 23 is formed hollow so that the oxygen-containing gas 4 can flow. Specifically, the gas introduction member 23 includes a flow path 231 of the oxygen-containing gas 4, a partition wall 232 and a side wall 233 surrounding the flow path 231, a baffle plate 234 disposed in the flow path 231, and a central rectifying plate 235. And an end baffle plate 236. Two baffle plates 234, a central side rectifying plate 235, and two end rectifying plates 236 are provided.

  The channel 231 preheats the oxygen-containing gas 4 by sequentially introducing the oxygen-containing gas 4 along the combustion chamber 22 and the cell stack 21. The preheated oxygen-containing gas 4 is supplied to the cell stack 21 at the downstream end of the flow path 231.

  The partition wall 232 partitions the flow path 231 from the combustion chamber 22 and the cell stack 21. Two combustion chambers 22 and two cell stacks 21 exist with the gas introduction member 23 interposed therebetween. Accordingly, there are two partition walls 232 across the flow path 231.

  The side wall 233 connects the two partition walls 232 at the end of the two partition walls 232 in the stacking direction D1.

  The gas introduction member 23 has an upstream portion 23a, a midstream portion 23b, and a downstream portion 23c in order toward the downstream side of the oxygen-containing gas 4. The upstream portion 23 a faces the combustion chamber 22. The midstream portion 23 b is connected to the downstream end of the upstream portion 23 a and faces the downstream portion of the cell stack 21. The downstream part 23 c is connected to the downstream end of the midstream part 23 b and faces the upstream part of the cell stack 21.

  The outer width X1 of the upstream portion 23a in the stacking direction D1 is smaller than the outer width X2 of the cell stack 21 in the stacking direction D1. If the outer width X1 of the upstream portion 23a is equal to or larger than the outer width X2 of the cell stack 21, the two combustion chambers 22 sandwiching the gas introduction member 23 are isolated from each other by the gas introduction member 23. On the other hand, in the first embodiment, since the outer width X1 of the upstream portion 23a is smaller than the outer width X2 of the cell stack 21, the two combustion chambers 22 sandwiching the gas introduction member 23 are communicated with each other. Since the two combustion chambers 22 communicate with each other, the combustion efficiency of the reaction gases 4 and 5 in the combustion chamber 22 can be improved as will be described later.

  The outer width in the stacking direction D1 of the midstream portion 23b and the downstream portion 23c is substantially the same as the outer width of the cell stack 21 in the stacking direction D1.

  The two baffle plates 234 are disposed downstream of the midstream portion 23b, that is, the upstream portion 23a. The baffle plates 234 are arranged at intervals in the stacking direction D1 so as to sandwich the central flow path 231a in the stacking direction D1. Each baffle plate 234 extends in the stacking direction D 1, and the outer end of each baffle plate 234 in the stacking direction D 1 reaches the side wall 233. Each baffle plate 234 is fixed between two partition walls 232 by welding. One end of the baffle plate 234 in the D3 direction may be spot welded to the one partition wall 232, and the other end in the D3 direction may be plug welded, that is, plug welded to the other partition wall 232. In plug welding, the baffle plate 234 can be welded from the outside of the other partition wall 232 through a hole formed in the other partition wall 232. Each baffle plate 234 concentrates the flow of the oxygen-containing gas 4 at the center of the gas introduction member 23 in the stacking direction D1.

  The two center-side rectifying plates 235 are disposed downstream of the downstream portion 23 c, that is, the baffle plate 234. Each center side rectification | straightening board 235 is arrange | positioned at intervals in the lamination direction D1 so that the center flow path 231a may be pinched | interposed. Each center-side rectifying plate 235 extends in the stacking direction D1. The inner end of each central side rectifying plate 235 in the stacking direction D1 is located inward from the inner end of the baffle plate 234, and the outer end of each central side rectifying plate 235 in the stacking direction D1 is from the inner end of the baffle plate 234. Located outside. Each center-side rectifying plate 235 is fixed between the two partition walls 232 by a welding method similar to that for the baffle plate 234. As shown in FIG. 1, each central side rectifying plate 235 forms a branch flow path 231 b that branches from the central flow path 231 a to the outside in the stacking direction D <b> 1 (that is, left and right) between each baffle plate 234. doing. Each center-side rectifying plate 235 disperses the flow of the oxygen-containing gas 4 concentrated in the center through the branch flow path 231b.

  The two end rectifying plates 236 are disposed downstream of the central rectifying plate 235 in the downstream portion 23c. The end rectifying plates 236 are arranged at intervals in the stacking direction D1 so as to sandwich the central flow path 231a and the branch flow path 231b. Each end rectifying plate 236 extends in the stacking direction D <b> 1, and the outer end of each end rectifying plate 236 in the stacking direction D <b> 1 reaches the side wall 233. Each end baffle plate 236 is fixed between the two partition walls 232 by the same welding method as the baffle plate 234. Each end rectifying plate 236 prevents the flow of the oxygen-containing gas 4 dispersed by the central rectifying plate 235 from concentrating on the end in the stacking direction D1.

  Next, the operation of the first embodiment will be described.

(Flow of oxygen-containing gas 4)
The blower 32 supplies the oxygen-containing gas 4 toward the cell stack 21. The oxygen-containing gas 4 supplied from the blower 32 flows into the gas introduction member 23 via the gas flow path in the storage container. The oxygen-containing gas 4 that has flowed into the gas introduction member 23 sequentially flows out from the downstream end of the gas introduction member 23 through the flow path 231 of the upstream portion 23a, the flow path 231 of the midstream portion 23b, and the flow path 231 of the downstream portion 23c. (Ie, erupting).

  The oxygen-containing gas 4 flowing out from the gas introduction member 23 is supplied to the cell stack 21 at the cell inlet at the lower end of the cell stack 21 and reaches the oxidant electrode of each solid oxide fuel cell 211. Part of the oxygen-containing gas 4 that has reached the oxidizer electrode receives the electrons emitted from the fuel electrode and becomes oxide ions. The oxide ions move to the fuel electrode through the electrolyte. The oxide ions that have moved to the fuel electrode react with hydrogen and carbon monoxide in the hydrogen-containing gas 5 to generate electrons. Thereby, the solid oxide fuel cell 211 generates power.

  Excess oxygen-containing gas 4 that has not been used for power generation is discharged from the cell stack 21 at the cell outlet of the cell stack 21 and flows into the combustion chamber 22. The oxygen-containing gas 4 flowing into the combustion chamber 22 reacts with the surplus hydrogen-containing gas 5 flowing into the combustion chamber 22 and burns. Combustion gas generated by the combustion is discharged to the outside of the storage container through the exhaust passage in the storage container.

(Flow of hydrogen-containing gas 5)
The fuel supply device 31 supplies natural gas and water as the fuel 50 to the reformer. The reformer generates water vapor by evaporating water, and generates hydrogen-containing gas 5 by reacting the generated water vapor with natural gas using a catalyst. The produced hydrogen-containing gas 5 reaches the manifold via the gas flow pipe. In the manifold, the hydrogen-containing gas 5 is supplied from the cell inlet to the cell stack 21 and reaches the fuel electrode of each solid oxide fuel cell 211. A part of the hydrogen-containing gas 5 reaching the fuel electrode generates electrons by the reaction at the fuel electrode as described above. The surplus hydrogen-containing gas 5 that has not been used for power generation is discharged to the outside after burning in the combustion chamber 22.

(Heat flow)
The oxygen-containing gas 4 that has flowed into the gas introduction member 23 first passes by the side of the combustion chamber 22 in the upstream portion 23a, thereby absorbing the heat of the combustion gas in the combustion chamber 22 by radiation or heat exchange. By absorbing heat, the oxygen-containing gas 4 is preheated. At this time, since the outer width X1 of the upstream portion 23a is smaller than the outer width X2 of the cell stack 21, the pair of combustion chambers 22 sandwiching the gas introduction member 23 communicate with each other. Thereby, in the combustion chamber 22 with a large volume, the surplus oxygen-containing gas 4 and the hydrogen-containing gas 5 discharged from the cell stack 21 are sufficiently mixed and burned well. When the oxygen-containing gas 4 and the hydrogen-containing gas 5 burn well, the solid oxide fuel cell 211 is sufficiently heated, and the power generation efficiency of the solid oxide fuel cell 211 is improved. Further, since the outer width X1 of the upstream portion 23a is smaller than the outer width X2 of the cell stack 21, the flow of the oxygen-containing gas 4 is concentrated at the center in the stacking direction D1, and cooling of the combustion chamber 22 is suppressed.

  Next, the oxygen-containing gas 4 cools the cell stack 21 by passing through the downstream portion of the cell stack 21 in the midstream portion 23b. At this time, the baffle plate 234 in the midstream portion 23b further concentrates the flow of the oxygen-containing gas 4 at the center in the stacking direction D1. As a result, the central portion of the cell stack 21 in the stacking direction D1 is intensively cooled, and the temperature of the central portion of the cell stack 21 in the stacking direction D1 that tends to become high temperature is sufficiently suppressed.

  Next, the oxygen-containing gas 4 is preheated by absorbing the heat of the cell stack 21 by passing through the upstream portion of the cell stack 21 in the downstream portion 23c. At this time, the central rectifying plate 235 in the downstream portion 23c disperses the flow of the oxygen-containing gas 4 concentrated in the center. Thereby, preheating of the oxygen-containing gas 4 is promoted. Further, the end rectifying plate 236 prevents the flow of the oxygen-containing gas 4 from concentrating on the end of the gas introduction member 23. Thereby, the temperature fall of the edge part of the lamination direction D1 of the cell stack 21 which tends to become low temperature is fully suppressed.

  As described above, according to the first embodiment, the combustibility of the reaction gases 4 and 5 in the combustion chamber 22 is improved by making the outer width X1 of the upstream portion 23a smaller than the outer width X2 of the cell stack 21. And cooling of the combustion chamber 22 can be suppressed. As a result, the cell voltage for the same supplied fuel flow rate and output current can be increased, and the power generation efficiency of the fuel cell system 1 can be improved.

  Further, according to the first embodiment, by concentrating the flow of the oxygen-containing gas 4 in the center of the stacking direction D1 by the baffle plate 234, the temperature of the center portion of the cell stack 21 in the stacking direction D1 can be suppressed. The cell stack 21 can be made highly durable in the hot module.

  Further, according to the first embodiment, since the flow of the oxygen-containing gas 4 is dispersed by the rectifying plate 235, the preheating of the oxygen-containing gas 4 can be promoted, so that the power generation efficiency can be further improved.

(Second Embodiment)
Next, a fuel cell module having an oxygen-containing gas supply hole will be described as a second embodiment. Note that, in the second embodiment, the same reference numerals are used for the components corresponding to the above-described embodiments, and redundant description is omitted. FIG. 2 is a schematic view of the fuel cell module 2 showing the second embodiment.

  As shown in FIG. 2, the fuel cell module 2 of the second embodiment includes a plurality of supply holes 24 that penetrate the partition 232 in addition to the configuration of the first embodiment. Each supply hole 24 is arranged in the vicinity of the downstream end of the downstream portion 23c with a gap in the stacking direction D1. Each supply hole 24 supplies the oxygen-containing gas 4 to the cell stack 21 downstream of the rectifying plates 235 and 236.

  According to the second embodiment, the flow of the oxygen-containing gas 4 dispersed by the rectifying plates 235 and 236 can be further dispersed by the supply holes 24. Thereby, since the preheating of the oxygen-containing gas 4 can be further promoted, the power generation efficiency can be further improved.

(Third embodiment)
Next, as a third embodiment, a fuel cell module including a baffle plate whose inner end is bent and a first rectifying plate will be described. Note that, in the third embodiment, the same reference numerals are used for the components corresponding to the above-described embodiments, and redundant description is omitted. FIG. 3 is a schematic diagram of the fuel cell module 2 showing the third embodiment.

  As shown in FIG. 3, the baffle plate 234 of the third embodiment is bent downstream at the inner end 234a in the stacking direction D1 in contact with the flow of the oxygen-containing gas 4 concentrated in the center. More specifically, the inner end 234a of the baffle plate 234 is bent 90 ° downstream with respect to the other part of the baffle plate 234 (the part extending in the stacking direction D1).

  The fuel cell module 2 of the third embodiment includes a first rectifying plate 237 instead of the central rectifying plate 235 described in the first embodiment. As shown in FIG. 3, the first rectifying plate 237 is recessed downstream at a position facing the inner end 234a of the baffle plate 234 so as to receive the flow of the oxygen-containing gas 4 concentrated in the center. Yes. Specifically, the first current plate 237 includes a first portion 237a extending in the stacking direction D1, and two second portions 237b extending upstream at both ends of the first portion 237a. The two second portions 237b are located outward in the stacking direction D1 from the inner ends 234a of the two baffle plates 234. It can also be said that the first current plate 237 has a tray shape. The first current plate 237 is fixed between the two partition walls 232 by a welding method similar to that for the baffle plate 234.

  As shown in FIG. 3, the first current plate 237 forms a meandering flow path 231 c between the inner end 234 a of the baffle plate 234. The flow path 231 c meanders the oxygen-containing gas 4 concentrated in the center by the baffle plate 234 in the vicinity of the center of the hottest cell stack 21. Since the oxygen-containing gas 4 meanders, the time during which the oxygen-containing gas 4 is preheated at the central portion of the cell stack 21, that is, the time during which the central portion of the cell stack 21 is cooled becomes longer. Thereby, the preheating of the oxygen-containing gas 4 can be further promoted, and the temperature of the central portion of the cell stack 21 can be further suppressed. Therefore, according to the third embodiment, the power generation efficiency can be further improved and the cell stack 21 can be further improved in durability.

(Fourth embodiment)
Next, a fuel cell module provided with a second rectifying plate will be described as a fourth embodiment. Note that, in the fourth embodiment, the same reference numerals are used for the components corresponding to the above-described embodiments, and redundant description is omitted. FIG. 4 is a schematic diagram of the fuel cell module 2 showing the fourth embodiment.

  As shown in FIG. 4, the fuel cell module 2 of the fourth embodiment includes a second rectifying plate 238 instead of the end rectifying plate 236 with respect to the fuel cell module 2 of the third embodiment. Is different. The second rectifying plate 238 is disposed outside the first rectifying plate 237 in the stacking direction D1. The second rectifying plate 238 extends stepwise (zigzag) inward and downstream in the stacking direction D1. The second baffle plate 238 is fixed between the two partition walls 232 by the same welding method as the baffle plate 234.

  As shown in FIG. 4, a flow path 231 d that meanders twice is formed between the baffle plate 234, the first rectifying plate 237, and the second rectifying plate 238. The flow path 231d causes the oxygen-containing gas 4 concentrated in the center by the baffle plate 234 to meander twice in the vicinity of the center of the hottest cell stack 21. When the oxygen-containing gas 4 meanders twice, the time during which the oxygen-containing gas 4 is preheated at the center of the cell stack 21, that is, the time during which the center of the cell stack 21 is cooled is further increased. Thereby, the preheating of the oxygen-containing gas 4 can be further promoted, and the temperature of the central portion of the cell stack 21 can be further suppressed. Therefore, according to the fourth embodiment, the power generation efficiency can be further improved as compared with the third embodiment, and the cell stack 21 can be further improved in durability.

(Fifth embodiment)
Next, a fuel cell module including a third rectifying plate will be described as a fifth embodiment. Note that, in the fifth embodiment, the same reference numerals are used for the components corresponding to the above-described embodiments, and redundant description is omitted. FIG. 5 is a schematic diagram of the fuel cell module 2 according to the fifth embodiment.

  As shown in FIG. 5, the fuel cell module 2 of the fifth embodiment includes a plurality of third rectifying plates 239 in addition to the configuration of the fourth embodiment. The third rectifying plate 239 faces the gap between the first rectifying plate 237 and the second rectifying plate 238 on the downstream side. One gap portion between the first rectifying plate 237 and the second rectifying plate 238 exists on each of the left and right sides of the first rectifying plate 237, but two third rectifying plates 239 are provided for each gap portion. Facing one by one. Each of the third rectifying plates 239 is arranged at an interval in the stacking direction D1. Each third rectifying plate 239 is fixed between the two partition walls 232 by a welding method similar to that for the baffle plate 234.

  The third rectifying plate 239 further disperses the oxygen-containing gas 4 that has passed between the first rectifying plate 237 and the second rectifying plate 238. Thereby, the preheating of the oxygen-containing gas 4 can be further promoted. Therefore, according to the fifth embodiment, the power generation efficiency can be further improved compared to the fourth embodiment.

(Sixth embodiment)
Next, as a sixth embodiment, a fuel cell module provided with a linear second rectifying plate will be described. Note that, in the sixth embodiment, the same reference numerals are used for the components corresponding to the above-described embodiments, and redundant description is omitted. FIG. 6 is a schematic diagram of the fuel cell module 2 according to the sixth embodiment.

  As shown in FIG. 6, the second rectifying plate 238 of the sixth embodiment is inward and downstream in the stacking direction D1 with respect to the second rectifying plate 238 (see FIG. 5) of the fifth embodiment. It differs in that it extends linearly to the side.

  According to the sixth embodiment, since the shape of the second rectifying plate 238 is a smooth straight line that is not bent, the second rectifying plate 238 can be manufactured at a low cost and the pressure loss of the oxygen-containing gas 4 can be reduced. Can be suppressed. By suppressing the pressure loss, the power consumption of the blower 32 (see FIG. 1) for sending the oxygen-containing gas 4 can be reduced, and the power generation efficiency of the fuel cell system 1 as a whole can be further improved.

(Seventh embodiment)
Next, a fuel cell module having inclined surfaces at the corners of the baffle plate 234 will be described as a seventh embodiment. Note that, in the seventh embodiment, the same reference numerals are used for the components corresponding to the above-described embodiments, and redundant description is omitted. FIG. 7 is a schematic diagram of the fuel cell module 2 according to the seventh embodiment.

  As shown in FIG. 7, the fuel cell module 2 of the seventh embodiment has an inclined surface 2341 at the corner of the baffle plate 234 that contacts the central flow path 231 a with respect to the fuel cell module 2 of the fifth embodiment. Is different. It can also be said that the baffle plate 234 has a corner portion that is obliquely processed (that is, chamfered). The inclined surface 2341 may be inclined by 45 ° with respect to the stacking direction D1, for example. Moreover, you may provide a curved surface (for example, circular arc surface) instead of an inclined surface.

  According to the seventh embodiment, since the separation of the flow of the oxygen-containing gas 4 can be reduced by the inclined surface 2341, pressure loss due to friction loss can be reduced. Thereby, the power consumption of the blower 32 which sends in the oxygen-containing gas 4 can be reduced, and the power generation efficiency of the fuel cell system 1 as a whole can be further improved.

(Eighth embodiment)
Next, as an eighth embodiment, a fuel cell module having inclined surfaces at the corners of the current plate will be described. In the eighth embodiment, the same reference numerals are used for the components corresponding to the above-described embodiments, and a duplicate description is omitted. FIG. 8 is a schematic diagram of the fuel cell module 2 according to the eighth embodiment.

  As shown in FIG. 8, the fuel cell module 2 of the eighth embodiment is different from the fuel cell module 2 of the seventh embodiment in that the corners of the first rectifying plate 237 in contact with the flow path 231 d meandering twice. And the second rectifying plate 238 have inclined surfaces 2371 and 2381 at the corners. The inclined surfaces 2371 and 2381 may be inclined by 45 ° with respect to the stacking direction D1, for example.

  According to the eighth embodiment, since the flow separation of the oxygen-containing gas 4 can be further reduced by the inclined surfaces 2371 and 2381, the pressure loss due to friction loss is further reduced as compared with the fuel cell module 2 of the seventh embodiment. it can. Thereby, the power consumption of the blower 32 which sends in the oxygen-containing gas 4 can be further reduced, and the power generation efficiency of the fuel cell system 1 as a whole can be further improved.

(Ninth embodiment)
Next, as a ninth embodiment, a fuel cell module in which baffle plates and rectifying plates are pressed will be described. Note that, in the ninth embodiment, the same reference numerals are used for the components corresponding to the above-described embodiments, and redundant description is omitted. FIG. 9 is a schematic diagram of the fuel cell module 2 according to the ninth embodiment.

  As shown in FIG. 9, the fuel cell module 2 of the ninth embodiment has a baffle plate 234 and first to third rectifying plates 237 to 239 pressed against the fuel cell module 2 of the fifth embodiment. The point which is integrally formed with the partition 232 by processing is different. Note that the pressing may be performed on either one or both of the two partition walls 232.

  By using the baffle plate 234 and the baffle plates 237 to 239 as press-molded bodies, the gas introduction member 23 can be manufactured at a lower cost than when the baffle plate 234 and the baffle plates 237 to 239 are welded. Therefore, according to the ninth embodiment, preheating of the oxygen-containing gas 4 and cooling of the central portion of the cell stack 21 can be realized at low cost.

(Tenth embodiment)
Next, a fuel cell module in which the inner diameter of the central supply hole is increased will be described as a tenth embodiment. Note that, in the tenth embodiment, the same reference numerals are used for the components corresponding to the above-described embodiments, and a duplicate description is omitted. FIG. 10 is a schematic diagram of the fuel cell module 2 according to the tenth embodiment.

  As shown in FIG. 10, the fuel cell module 2 of the tenth embodiment is different from the fuel cell module 2 of the fifth embodiment in that the inner diameters of the plurality of supply holes 24 on the center side are the other supply holes 24. It is different in that it is larger than the inner diameter.

  The supply hole 24 on the center side in the stacking direction D1 having a large inner diameter can supply more oxygen-containing gas 4 to the solid oxide fuel cell 211 in the center in the stacking direction D1. Therefore, according to the tenth embodiment, since the temperature of the central portion of the cell stack 21 in the stacking direction D1 can be further suppressed, the cell stack 21 can be made more durable in the hot module as compared with the fifth embodiment. . Further, since the pressure loss can be reduced because the inner diameter of the supply hole 24 is large, the power consumption of the blower 32 for sending the oxygen-containing gas 4 can be reduced, and the power generation efficiency of the fuel cell system 1 as a whole can be further improved.

(Eleventh embodiment)
Next, an eleventh embodiment will be described. FIG. 11 is a schematic diagram of the fuel cell module 2 according to the eleventh embodiment.

  As shown in FIG. 11, in the fuel cell module 2 of the eleventh embodiment, the baffle plate 234 is formed larger in the flow direction of the oxygen-containing gas 4 than the fuel cell module 2 of the first embodiment. Another difference is that there is no current plate.

  According to the eleventh embodiment, the outer width X1 of the upstream portion 23a is smaller than the outer width X2 of the cell stack 21, so that the outer width X1 of the upstream portion 23a is larger than the outer width X2 of the cell stack 21. The combustibility of the oxygen-containing gas 4 and the hydrogen-containing gas 5 can be improved.

(Experimental example)
Next, an experimental example of the fuel cell module 2 will be described. FIG. 12 is a diagram illustrating an experimental example of the fuel cell module. In this experimental example, 3D of analysis target data (samples 1 to 10) simulating the fuel cell modules 2 of the first to eighth, tenth and eleventh embodiments using fluid analysis software (STAR-CCM +). Fluid analysis was performed. The correspondence between the sample number and the embodiment is as shown in FIG. In the present experimental example, the temperature of the oxygen-containing gas 4 supplied to the gas introduction member 23 was set to 750K. In this experimental example, the temperature of the partition 232 was set to 1000K.

  Under such temperature conditions, the average temperature [K] of the oxygen-containing gas 4 at the downstream end of the gas introduction member 23, that is, the outlet, and the pressure loss of the oxygen-containing gas 4 in the gas introduction member 23 with respect to the samples 1 to 10. [Pa] was simulated. The result is shown in FIG.

  As shown in FIG. 12, the samples with a small pressure loss of the gas introduction member 23 were Samples 1 and 2 simulating the fuel cell module 2 of the first and second embodiments. In Samples 1 and 2, since the current plate has a shape extending only in the stacking direction D1, the flow path does not meander, and it is assumed that the pressure loss due to the peeling phenomenon is reduced as a result.

  Also, as shown in FIG. 12, samples having a high average temperature of the oxygen-containing gas 4 at the outlet of the gas introduction member 23 were Samples 3 to 9 corresponding to the third to eighth and tenth embodiments. In Samples 3 to 9, it is presumed that the preheating of the oxygen-containing gas 4 was promoted in the flow path meandering with the rectifying plate, and as a result, the average temperature at the outlet was increased.

  Of the samples 3 to 9 having a high average temperature of the oxygen-containing gas 4, the samples with relatively small pressure loss were the samples 3, 6 and 9. In the sample 3, it is presumed that since the third rectifying plate 239 does not exist, the oxygen-containing gas 4 does not branch at the third rectifying plate 239, and as a result, the pressure loss is reduced. In the sample 6, the second rectifying plate 238 is linear, so that the peeling phenomenon is alleviated compared to the case where the second rectifying plate 238 is bent, and as a result, the pressure loss is estimated to be small. The In the sample 9, it is presumed that the pressure loss is reduced due to the large inner diameter of the central supply hole 24.

  In the experimental example, the temperature of the partition wall 232 is kept constant at 1000 K. Actually, however, the cell stack 21 has a temperature distribution such that the central portion in the stacking direction D1 is high and the end is low. The temperature of the partition wall 232 at the end of 21 is estimated to be about 900K. That is, as with the cell stack 21, a temperature distribution also exists in the partition wall 232. Here, in the sample 3 simulating the third embodiment (see FIG. 3), a large amount of the oxygen-containing gas 4 flows near the end of the cell stack 21, so the center of the gas introduction member 23 is caused by the temperature distribution of the partition walls 232. It is estimated that the air preheating effect is lower than when the oxygen-containing gas 4 flows on the side. Actually, it is presumed that the sample 6 simulating the sixth embodiment (see FIG. 6) has a higher average temperature of the oxygen-containing gas 4 at the outlet of the gas introduction member 23 than the sample 3.

  Also, in comparison between the sample 5 simulating the fifth embodiment (see FIG. 5) and the sample 9 simulating the tenth embodiment (see FIG. 10), the hole 24 is actually large and the cell stack 21 It is estimated that the average temperature of the oxygen-containing gas 4 at the outlet of the gas introduction member 23 is higher in the sample 9 in which the oxygen-containing gas 4 flows more in the vicinity of the center than in the sample 5.

According to at least one embodiment described above, the flammability of the reaction gas can be improved.
Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

2 Fuel cell module, 21 cell stack, 22 combustion chamber, 23 gas introduction member, 231 flow path, 232 partition wall, 23a upstream part

Claims (7)

A cell stack having a plurality of stacked fuel cells, and allowing the first reaction gas and the second reaction gas to flow in a direction perpendicular to the stacking direction of the fuel cells,
A combustion chamber disposed downstream of the cell stack in the flow direction of the first and second reaction gases and burning the first and second reaction gases discharged from the cell stack; and the stacking direction And a gas introduction member facing the combustion chamber and the cell stack in a direction orthogonal to the flow direction, and sequentially introducing the first reaction gas along the combustion chamber and the cell stack. Gas introduction having a flow path for preheating the first reaction gas and supplying the preheated first reaction gas to the cell stack at a downstream end, and a partition wall partitioning the flow path, the combustion chamber, and the cell stack A member, and
Upstream portion of said gas introduction member facing the combustion chamber, the outer shape width of the stacking direction is rather smaller than the cell stack,
The gas introduction member is
A plurality of baffle plates arranged downstream of the upstream portion and concentrating the flow of the first reactive gas at the center in the stacking direction;
A plurality of baffle plates arranged downstream of the plurality of baffle plates and dispersing the flow of the first reactive gas concentrated in the center,
The plurality of baffle plates are bent downstream at the inner end in the stacking direction in contact with the flow of the first reaction gas concentrated at the center,
The plurality of rectifying plates are recessed downstream at a position facing the inner end so as to receive the flow of the first reaction gas concentrated at the center, and the flow of the first reaction gas is flown in the stacking direction. A fuel cell module including a first current plate that faces outward and downstream . 2. The fuel cell according to claim 1 , wherein the plurality of rectifying plates include a second rectifying plate that is disposed outward in the stacking direction with respect to the first rectifying plate and extends inward and downstream in the stacking direction. module. 3. The fuel cell module according to claim 2 , wherein the plurality of rectifying plates include a third rectifying plate facing a gap portion between the first rectifying plate and the second rectifying plate on the downstream side. The fuel cell module according to any one of claims 1 to 3 , wherein at least one of the plurality of baffle plates and the plurality of rectifying plates has an inclined surface or a curved surface at a corner. Said gas introduction member is provided in the partition wall at intervals in the stacking direction, claims 1 to 4, comprising a plurality of supply holes for supplying the first reaction gas to the cell stack downstream of the rectifier plate The fuel cell module according to any one of the above. 6. The fuel cell module according to claim 5 , wherein among the plurality of supply holes, a supply hole on a central side in the stacking direction has a larger inner diameter than other supply holes. A fuel cell module, and an auxiliary machine for operating the fuel cell module,
The fuel cell module is
A cell stack having a plurality of stacked fuel cells, and allowing the first reaction gas and the second reaction gas to flow in a direction perpendicular to the stacking direction of the fuel cells,
A combustion chamber disposed downstream of the cell stack in the flow direction of the first and second reaction gases, and combusting the first and second reaction gases discharged from the cell stack;
A gas introduction member facing the combustion chamber and the cell stack in a direction orthogonal to the stacking direction and the flow direction, and sequentially introduces the first reaction gas along the combustion chamber and the cell stack. A flow path for preheating the first reaction gas and supplying the preheated first reaction gas to the cell stack at a downstream end; and a partition wall partitioning the flow path, the combustion chamber, and the cell stack. A gas introduction member having,
Upstream portion of said gas introduction member facing the combustion chamber, the outer shape width of the stacking direction is rather smaller than the cell stack,
The gas introduction member is
A plurality of baffle plates arranged downstream of the upstream portion and concentrating the flow of the first reactive gas at the center in the stacking direction;
A plurality of baffle plates arranged downstream of the plurality of baffle plates and dispersing the flow of the first reactive gas concentrated in the center,
The plurality of baffle plates are bent downstream at the inner end in the stacking direction in contact with the flow of the first reaction gas concentrated at the center,
The plurality of rectifying plates are recessed downstream at a position facing the inner end so as to receive the flow of the first reaction gas concentrated at the center, and the flow of the first reaction gas is flown in the stacking direction. A fuel cell system including a first baffle plate directed outward and downstream .

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