JP5977143B2 - Fuel cell module - Google Patents

Description

  The present invention relates to a fuel cell module having a plurality of cell stacks in a housing.

  2. Description of the Related Art In recent years, fuel cells that can obtain electric power using a hydrogen-containing gas and an oxygen-containing gas (air) are known as next-generation energy. Further, a cell stack device in which a plurality of fuel cells are arranged in a row and electrically connected in series is provided in a gas tank, and the cell stack device is housed in a housing. Various fuel cell modules have been proposed (see, for example, Patent Document 1).

JP 2005-183375 A

  In recent years, the use of fuel cells has been studied in addition to home use. For example, fuel cells for business use such as hospitals, hotels, stores, etc. require a power generation amount of several kW or more. Therefore, it is necessary to store a large number of cell stacks densely in the housing, and the temperature of the central portion of the cell stack assembly consisting of a large number of cell stacks increases, so that the cell stack positioned at the central portion of the cell stack assembly As a result, the power generation performance of the fuel cell module may be reduced.

  An object of the present invention is to provide a fuel cell module that can achieve a uniform temperature of a cell stack assembly during power generation.

A fuel cell module of the present invention includes a plurality of cell stacks in which a plurality of fuel cells having gas flow paths are arranged in a line, and the plurality of fuel cells are electrically connected to each other, and the fuel cell A fuel gas tank in which lower end portions of the plurality of cell stacks are respectively fixed, and a flat plate disposed so as to be positioned above a cell stack assembly composed of the plurality of cell stacks so that fuel gas flows through the gas flow path. A first reformer having a shape, a plurality of second reformers each having an upper end fixed to the first reformer, and a lower end fixed to the fuel gas tank through the cell stack; A reforming catalyst that performs steam reforming housed in the reformer, and the second reformer is disposed at a central portion and a peripheral portion of the cell stack assembly, and the cell stack Center of the aggregate Toward the periphery from, characterized in that the distance between the second reformer adjacent wider.

  In the fuel cell module according to the present invention, the central portion of the cell stack assembly tends to accumulate heat and the temperature tends to increase. For example, the second reformer is provided between the cell stacks in the central portion of the cell stack assembly. As a result, when the reforming catalyst performs steam reforming, the heat around the second reformer can be absorbed, and the temperature around the second reformer can be lowered, whereby the center of the cell stack assembly can be reduced. The temperature of the cell stack in the section can be lowered, and the temperature of the cell stack assembly can be made uniform during power generation.

1 shows a fuel cell module, in which (a) is a longitudinal sectional view, (b) is a sectional view taken along line BB, and (c) is a sectional view taken along line CC. It is an enlarged view which expands and shows a part of cell stack aggregate | assembly of FIG.1 (c). It is sectional drawing which shows the fuel cell module which changed the arrangement position of a 2nd reformer, (a) shows the form which has arrange | positioned the 2nd reformer in the center of each cell stack column of 2 rows, (b) Shows a configuration in which three second reformers are arranged in the center of the central cell stack column among the three cell stack columns. FIG. 2 is a longitudinal sectional view showing a state in which the amount of reforming catalyst in the second reformer at the center of the cell stack assembly of the fuel cell module of FIG. The state packed from the fuel gas tank side, (b) shows the state in which the reforming catalyst is accommodated in the portion located at the center in the length direction of the fuel cell. The longitudinal cross-sectional view which shows the fuel cell module of the state which made the accommodation space of the reforming catalyst of the 2nd reformer in the center part of the cell stack aggregate | assembly of the fuel cell module of FIG. 1 wider than the 2nd reformer in the periphery. It is. It is sectional drawing which shows the fuel cell module of the state which expanded the cell arrangement direction center part in the 2nd reformer of the fuel cell module of FIG. FIG. 2 is a perspective view showing a state in which a heat transfer body is provided inside a second reformer at a central portion of the cell stack assembly of the fuel cell module of FIG. 1, and (a) alternately provides plate-like heat transfer bodies. (B) shows the state which provided the columnar heat exchanger. It is sectional drawing of the fuel cell module which shows the state in which the 2nd reformer was provided ranging over two cell stack rows.

  FIG. 1 shows an embodiment of the fuel cell module of the present invention. As shown in FIGS. 1 and 2, the fuel cell module has a plurality of cell stacks 1, a fuel gas tank 3, a flat plate-shaped first reformer 5, and a first upper end portion in a housing (not shown). And a plurality of second reformers 7 fixed to the reformer 5. A reforming catalyst 9 that performs steam reforming is accommodated in the first reformer 5 and the second reformer 7.

  As shown in FIG. 2, the cell stack 1 is configured by arranging a plurality of fuel cells 11 in a row and electrically connecting them. That is, a plurality of columnar fuel cells 11 having a plurality of gas passages 11a through which fuel gas flows are arranged in a row in a standing state, and current collecting members (between adjacent fuel cells 3) The cell stack 1 is configured by being electrically connected in series via a not-shown fuel cell, and the fuel cell is arranged so as to sandwich the cell stack 1 from both ends in the cell arrangement direction x of the fuel cell 11 of the cell stack 1. An end current collecting member 13 having a current drawing portion for drawing a current generated by the power generation of the cell 11 is arranged. In FIG. 1C, the description of the end current collecting member 13 and the like is omitted, and the description of the fuel battery cell 11 is partially omitted.

  The lower ends of the fuel cells 11 and the end current collecting members 13 constituting the cell stack 1 are fixed to the fuel gas tank 3 by an insulating bonding material (not shown) such as a glass seal material. The fuel battery cell 11 has gas flow paths 11a penetrating in the vertical direction (length direction L), and a plurality of cell stacks 1 are provided so that fuel gas is supplied to these gas flow paths 11a. Lower end portions are respectively fixed to the upper wall of the fuel gas tank 3.

  In FIG. 1, 16 cell stacks 1 are arranged in a matrix on one fuel gas tank 3. That is, a plurality of cell stacks 1 are arranged so that the arrangement direction x of the fuel battery cells 11 constituting the cell stack 1 is parallel to form a cell stack row, and the two cell stack rows are arranged in parallel. A plurality of cell stacks 1 form a matrix to form a cell stack aggregate G.

The cell stacks 1 are arranged in parallel so that the cell arrangement directions x of the fuel cells 11 are parallel to each other. As shown in FIG. 2, the current drawing portions 22 on the same side of the cell stack 1 are electrically connected to each other. By connecting with the connecting member 21, the eight cell stacks 1 are connected in series.

  The fuel battery cell 11 is, for example, a hollow plate type having a gas flow path 11a through which a hydrogen-containing gas (fuel gas) flows in the length direction L. A fuel-side electrode layer, a solid electrolyte is formed on the surface of the support. A solid oxide fuel cell 11 in which a layer and an oxygen electrode layer are sequentially provided is illustrated. The fuel cell 11 has a power generation unit in which a fuel-side electrode layer, a solid electrolyte layer, and an oxygen-side electrode layer are superimposed on substantially the entire length direction L (standing direction). In addition to the above, as the fuel cell 11, for example, a cylindrical or flat fuel cell can be used.

  The flat plate-like first reformer 5 and the plurality of second reformers 7 contain therein a reforming catalyst 9 that performs steam reforming, and obtains fuel gas used for power generation of the fuel cell 11. For this purpose, fuel gas is generated by reforming raw fuel such as natural gas or kerosene. Although not shown, the first reformer 5 has a vaporizing unit that vaporizes water. The vaporization unit may be disposed separately from the first reformer 5, for example, on the upper surface of the first reformer 5.

  The reforming catalyst 9 performs steam reforming during power generation. For example, the reforming catalyst 9 may perform partial oxidation reforming at startup. Further, it is sufficient that the reforming catalyst 9 is accommodated in the second reformer 7, and the reforming catalyst 9 is not necessarily accommodated in the first reformer 5.

  The flat plate-shaped first reformer 5 is disposed so as to be positioned above the cell stack assembly G, and the upper ends of the plurality of second reformers 7 are fixed to the first reformer 5, The lower end portion extends downward from the first reformer 5 and is connected to the upper wall of the fuel gas tank 3 through the cell stack 1.

  The first reformer 5 is divided into upper and lower parts by a partition member 15, the upper part is a catalyst chamber 5 a in which the reforming catalyst 9 is accommodated, and the lower part is a reformed gas reformed by the reforming catalyst. Is introduced into the reformed gas chamber 5b, and the reformed gas chamber 5b communicates with the internal spaces of the plurality of second reformers 7. Therefore, raw fuel such as city gas is supplied to the first reformer 5, and the reformed gas that has been reformed to some extent is introduced into the reformed gas chamber 5 b through the opening 15 a formed in the partition member 15. Thereafter, the gas is supplied to the second reformer 7 to be further reformed, and this reformed gas (hereinafter sometimes referred to as fuel gas) is supplied into the fuel gas tank 3 so that the fuel gas flow of the fuel cell 11 is The fuel gas that has flowed through the path 11a and was not used for power generation is discharged from the upper end of the fuel cell 11 to the first reformer 5 side.

  For the reforming catalyst 9 accommodated in the catalyst chamber 5a of the first reformer 5 and the plurality of second reformers 7, for example, commonly used materials such as Ru and Ni are formed on the surface of the carrier. Used by being supported. The reforming catalyst 9 is, for example, granular, and the granular reforming catalyst 9 is filled in the catalyst chamber 5 a of the first reformer 5 and the plurality of second reformers 7. Then, for example, a raw fuel such as city gas and water vapor are introduced into the catalyst chamber 5a of the first reformer 5, and a part thereof is reformed to hydrogen while passing between the granular reforming catalysts. The reformed gas is supplied to the second reformer 7 via the reformed gas chamber 5b, and raw fuel such as city gas that has not been reformed is reformed into hydrogen and introduced into the fuel gas tank 3. Become.

  A mesh (not shown) is provided at the opening 15a of the partition member 15 and the upper and lower ends of the second reformer 7 in order to hold the reforming catalyst 9 in the catalyst chamber 5a and the second reformer 7. Is arranged.

  In FIG. 1C, the second reformer 7 is disposed in the central portion of the cell stack assembly G, and is also disposed in the peripheral portion. Note that the central portion of the cell stack aggregate G is a concept including the center of the cell stack row as shown in FIG.

  The second reformer 7 has a flat plate shape and is arranged for every two cell stacks 1, and three second reformers 7 are arranged in one cell stack row. One flat first reformer 5 and a total of six second reformers 7 are arranged.

  In the fuel cell module configured as described above, the central portion of the cell stack assembly G tends to be hot and the temperature tends to increase. Since the two reformers 7 are arranged, when the reforming catalyst 9 performs steam reforming, the heat around the second reformer 7 can be absorbed, and the temperature around the second reformer 7 can be lowered, Thereby, the temperature of the cell stack 1 in the center part of the cell stack assembly G can be lowered, and the temperature of the cell stack assembly G can be made uniform during power generation. Thereby, power generation performance can be improved.

  Even in the fuel cell module having the cell stack assembly G shown in FIGS. 3 (a) and 3 (b), the temperature of the cell stack 1 at the center of the cell stack assembly G is reduced, and the cell stack during power generation is reduced. The temperature of the assembly G can be made uniform.

  That is, as shown in FIG. 3A, in the fuel cell module having the cell stack assembly G having two cell stack columns each including eight cell stacks 1, the center of the two cell stack columns A second reformer 7 is disposed in each of the two. In addition, as shown in FIG. 3B, in the fuel cell module having the cell stack assembly G having three cell stack columns each including eight cell stacks 1, the central portion of the central cell stack column The three second reformers 7 are alternately arranged with the cell stack 1.

  In particular, as shown in FIG. 3B, when the periphery of the central cell stack 1 is surrounded by other cell stacks 1, heat is easily trapped, so that the present invention can be suitably used.

  FIG. 4 shows the degree of filling of the reforming catalyst 9 in the second reformer 7, and the reforming in the second reformer 7 at the center of the cell stack assembly G of the fuel cell module shown in FIG. It is a longitudinal cross-sectional view which shows the state which increased the catalyst amount from the periphery, (a) is the state which packed the reforming catalyst 9 from the fuel gas tank 3, and (b) is the length direction L ( This is a state in which the reforming catalyst 9 is accommodated in the center portion in the height direction of the cell stack).

  In FIG. 4, the second reformer 7 is arranged in the central portion and the peripheral portion of the cell stack assembly G so that the interval between the adjacent second reformers 7 is the same interval.

  Even in such a fuel cell module, the temperature of the cell stack 1 at the center of the cell stack assembly G can be lowered and the temperature of the cell stack assembly G can be made uniform during power generation, but it is arranged at the center of the cell stack row. The amount of the reforming catalyst in the second reformer 7 is made larger than the amount of the reforming catalyst in the second reformer 7 arranged in the periphery of the cell stack row, so that the cell stack assembly G The reforming reaction in the second reformer 7 disposed in the center (the amount of heat absorbed by the reforming catalyst 9) is reformed in the second reformer 7 disposed in the periphery of the cell stack assembly G. It becomes more active (more) than the reaction (the amount of heat absorbed by the reforming catalyst 9), and the temperature of the cell stack 1 at the center of the cell stack assembly G, which tends to be particularly high, can be lowered most. The temperature of the assembly G It can be made uniform. When the reforming catalyst is made of the same material, the large amount of reforming catalyst means that the reforming reaction in the second reformer 7 becomes active, and the amount of heat absorbed by the reforming catalyst 9. It is also that there are many.

In the case of FIG. 4B, the temperature distribution in the length direction L of the fuel cell 11 can also be made uniform. That is, in the cell stack 1, the temperature may increase at the center portion in the length direction L of the fuel battery cell 11, but in the case of FIG. 4B, the center of the fuel battery cell 11 in the height direction. Since the reforming catalyst 9 is housed in the portion of the second reformer 7 located in the section, the temperature of the central portion in the length direction L of the fuel cell 11 can be lowered, and the fuel cell 11 The temperature distribution in the length direction L can also be made uniform. In FIG. 4B, the case where the temperature of the central portion in the length direction L of the fuel cell 11 is increased is described. However, when the temperature of the upper end portion of the fuel cell 11 is increased, the fuel cell The reforming catalyst 9 can be accommodated in the upper end portion side of the cell 11.

  5 shows the volume of the internal space of the second reformer 7 at the center of the cell stack assembly G of the fuel cell module shown in FIG. The volume of the reforming catalyst in the second reformer 7 in the central part of the cell stack assembly G was made larger than that in the vicinity, with the volume of the internal space being larger. Even in such a fuel cell module, the temperature of the cell stack 1 at the center of the cell stack assembly G can be lowered, and the temperature of the cell stack assembly G during power generation can be made more uniform.

  FIG. 6 shows the second reformer 7 of the fuel cell module shown in FIG. 1, in which a widened portion 7 a is provided at the center in the arrangement direction x of the fuel cells 11 in the cell stack 1. The internal space of the cell stack is filled with the reforming catalyst 9, and the temperature of the cell stack 1 at the center of the cell stack assembly G can be lowered, and the temperature of the cell stack assembly G can be made uniform during power generation. In addition, the temperature distribution in the arrangement direction x of the fuel cells 11 can be made uniform. That is, in the cell stack 1, the temperature tends to increase at the center portion in the arrangement direction x of the fuel cells 11, but in the case of FIG. 6, it is located at the center portion in the arrangement direction x of the fuel cells 11. Since many reforming catalysts 9 are accommodated in the widened portion 7 a of the second reformer 7, the temperature of the central portion in the arrangement direction x of the fuel cells 11 can be particularly lowered, and the fuel cells 11 The temperature distribution in the arrangement direction x can also be made uniform.

  In addition to changing the amount of the reforming catalyst, for example, by changing the material of the reforming catalyst 9, the reforming reaction (endothermic amount) in the second reformer 7 disposed at the center of the cell stack assembly G can be achieved. ) Can be more active (increase) than the reforming reaction (endothermic amount) in the second reformer 7 disposed in the periphery of the cell stack assembly G. Therefore, the reforming catalyst material may be changed with the same amount of reforming catalyst in the central portion and the peripheral portion of the cell stack assembly G. Changing the reforming catalyst material includes changing the catalytic metal species, supported amount, particle size, particle shape, and the like, and changes the endothermic amount.

  In the above embodiment, the case where the intervals between the adjacent second reformers 7 arranged in the same cell stack row are arranged to be uniform has been described. The fuel cell module in which the interval between the adjacent second reformers 7 arranged in the same cell stack row becomes wider, that is, the further away from the second reformer 7 in the center, Even if the number of cell stacks 1 arranged between the adjacent second reformers 7 is increased, the temperature in the cell stack aggregate G can be made more uniform.

  FIG. 7 shows a state in which the heat transfer body 25 is arranged in the second reformer 7 in the center of the cell stack row in the fuel cell module shown in FIG. 1, and FIG. The plate-like heat transfer bodies 25 are alternately arranged in the second reformer 7 at the center of the row, and the gas is meandering in the second reformer 7. The heat transfer body 25 is made of a material having a higher thermal conductivity than the material constituting the second reformer 7.

In such a fuel cell module, since the gas meanders in the second reformer 7, the reforming catalyst 9 that performs steam reforming in the second reformer 7 includes the heat transfer body 25 and the second reformer. Heat can be further absorbed from the periphery of the second reformer 7 via the unit 7, and the control of the temperature of the cell stack assembly G during power generation is further facilitated. Further, by disposing the heat transfer body 25 in the center portion in the length direction L of the fuel battery cell 11, the temperature of the center portion in the length direction L of the fuel battery cell 11 can also be lowered. The temperature distribution in the length direction L of 11 can be made uniform.

  In the case of FIG. 7A, the case where the temperature of the center portion in the length direction L of the fuel battery cell 11 is increased is described. However, when the temperature of the upper end portion of the fuel battery cell 11 is increased. By arranging the heat transfer body 25 on the upper end side of the fuel battery cell 11, the temperature distribution in the length direction L of the fuel battery cell 11 can also be made uniform.

  FIG. 7B shows a case where a plurality of columnar heat transfer bodies 25 are arranged in the center of the second reformer 7 in the cell arrangement direction x. In the fuel cell module, although the effect of changing the gas flow is small, it becomes easier to absorb heat from the heat transfer body 25, and the temperature of the cell stack 1 at the center of the cell stack assembly G can be further reduced.

  FIG. 8 shows a fuel cell module in which the second reformer 7 is provided across the two cell stack rows in the fuel cell module shown in FIG. The temperature of the cell stack 1 at the center of G can be lowered.

  Although the present invention has been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and improvements can be made without departing from the scope of the present invention.

  In the above embodiment, the fuel cell module having one first reformer 5 and one fuel gas tank has been described. However, the fuel cell module may have a plurality of first reformers, and a plurality of fuel gas tanks. May be included.

DESCRIPTION OF SYMBOLS 1 ... Cell stack 3 ... Fuel gas tank 5 ... 1st reformer 5a ... Catalyst chamber 5b ... Reformed gas chamber 7 ... 2nd reformer 11 ... Fuel cell Cell 11a ... Gas channel 15 ... Partition member 25 ... Heat transfer body G ... Cell stack assembly

Claims (5)

A plurality of fuel cells having gas flow paths are arranged in a line, a plurality of cell stacks in which the plurality of fuel battery cells are electrically connected to each other, and a fuel gas flows through the gas flow paths of the fuel cells. As described above, a fuel gas tank in which lower ends of the plurality of cell stacks are respectively fixed, and a flat plate-shaped first reformer disposed so as to be positioned above a cell stack assembly including the plurality of cell stacks, A plurality of second reformers having an upper end fixed to the first reformer and a lower end fixed to the fuel gas tank through the cell stack, and housed in the second reformer. A reforming catalyst for performing steam reforming , wherein the second reformer is disposed in a central portion and a peripheral portion of the cell stack assembly, and from the central portion to the peripheral portion of the cell stack assembly. The more adjacent Fuel cell module, wherein a distance between the second reformer is widened. Break before Symbol endotherm by the reforming catalyst in said second reformer which is disposed in a central portion of the cell stack assembly is, the cell stack assembly within the second reformer which is disposed on the periphery of the 2. The fuel cell module according to claim 1, wherein the fuel cell module has a larger amount of heat absorption by the porous catalyst. The fuel cell module according to claim 1 or claim 2 in the second reformer, characterized in that the heat conductor is arranged. The first reformer is divided into upper and lower parts by a partition member, the upper part is a catalyst chamber containing the reforming catalyst, and the lower part is introduced with a reformed gas reformed by the reforming catalyst. that are the reformed gas chamber, a fuel cell according to any one of claims 1 to 3 and the reforming gas chamber and the plurality of the second reformer is characterized in that in communication module. The plurality of cell stacks are arranged to form a cell stack column so that the arrangement directions of the fuel cells constituting the cell stack are parallel to each other, the cell stack columns are arranged in parallel to each other, and the plurality of cell stack columns are arranged in parallel. The fuel cell module according to any one of claims 1 to 4 , wherein the cell stack assembly is configured by forming a cell stack in a matrix.

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