JP2009231187A - Fuel cell module and fuel cell including it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell module surely insulating a current collecting member from a heat conductive member and enhancing construction property. <P>SOLUTION: The fuel cell module FC includes a plurality of fuel cell stacks 21a-21c, a container 8, a heat insulating member 9 arranged between the plurality of fuel cell stacks 21a-21c and the container 8, a current collecting member 3 electrically connecting the plurality of fuel cell stacks 21a-21c, an insulating member 16 arranged between the adjacent fuel cell stacks 21A-21c, and a heat conductive member 15, and the insulating member 16 is separately arranged so as to come in contact with each of one side and the other side of the adjacent fuel cell stacks 21a-21c, and the heat conductive member 15 is arranged between a pair of insulating members 16, and has an insulating rod 11 formed by a material having electric insulating property between the current collecting member 3 and the heat conductive member 15 as a member independent of the heat insulating member 9. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell module including a plurality of fuel cells and a fuel cell including the same.

  Solid oxide fuel cells that use ceramic materials for fuel cells can utilize the exhaust heat that is generated during power generation, and are therefore being developed as highly efficient power generation systems. In order to obtain a high electrical output, a solid oxide fuel cell module used for such a solid oxide fuel cell is generally a cell stack assembly in which fuel cell stacks each having a plurality of fuel cells are assembled. I have.

  In such a solid oxide fuel cell module, since the fuel cell generates heat due to Joule heat at the time of power generation, a temperature difference occurs between the fuel cell and the introduced fuel gas and oxidizing gas. It will be partially cooled. For this reason, temperature distribution occurs in the fuel cell, which not only deteriorates the performance of the fuel cell, but also may cause damage to the fuel cell due to thermal stress.

In order to make the temperature distribution of the fuel cell uniform, a partition member sandwiching the heat conducting member between both sides of the fuel cell stack between the insulating members is arranged between the fuel cell stacks. There is known a solid oxide fuel cell module (see, for example, Patent Document 1) that ensures insulation between the fuel cell and the fuel cell.
JP 2007-157424 A

  The solid oxide fuel cell module as described above is provided with an inter-stack current collecting member for electrically connecting adjacent fuel cell stacks, and is a heat conducting member disposed between the fuel cell stacks. It is necessary to electrically insulate the end of the heat conducting member and the inter-stack current collecting member so as not to leak due to contact with each other. In the solid oxide fuel cell module described above, the end of the heat conducting member and the inter-stack current collecting member are electrically connected to each other by using the heat insulating and insulating member provided between the stack current collecting members inside the metal container. Thus, the current collecting member between the stacks becomes complicated and there is a problem in workability when assembling.

  Therefore, in the present invention, a fuel cell that is excellent in workability while reliably insulating a current collecting member that electrically connects the fuel cell stacks and a heat conducting member for making the temperature distribution of the fuel cells uniform. It is an object to provide a module and a fuel cell including the fuel cell module.

  In order to achieve the above object, a fuel cell module according to the present invention includes a plurality of fuel cell stacks formed by electrically connecting a plurality of fuel cells operated by a fuel gas and an oxidant gas. A container for accommodating the plurality of fuel cell stacks, a heat insulating member disposed between the plurality of fuel cell stacks and the container, and electrically connecting the plurality of fuel cell stacks A current collecting member that is formed of a material having electrical insulation properties, an insulating member disposed between the fuel cell stacks adjacent to each other, and a direction in which the fuel cell extends, A heat conductive member formed of a material having higher heat conductivity than the insulating member, and the insulating member is disposed on one side of the fuel cell stack adjacent to each other. The first insulating member and the second insulating member are arranged so as to be in contact with each side, and the heat conducting member is arranged between the first insulating member and the second insulating member. A third insulating member formed of an electrically insulating material is provided as a member independent of the heat insulating member between the current collecting member and the heat conducting member.

  According to the present invention, a current collecting member that electrically connects fuel cell stacks and a heat conducting member for uniformizing the temperature distribution of the fuel cells are reliably insulated, and a fuel cell that is excellent in workability. Modules can be provided.

  Prior to describing the best mode for carrying out the present invention, the function and effect of the present invention will be described.

  A fuel cell module according to the present invention includes a plurality of fuel cell stacks formed by electrically connecting a plurality of fuel cells operated by a fuel gas and an oxidant gas, and the plurality of fuel cell stacks. A container for containing the battery, a heat insulating member disposed between the plurality of fuel cell stacks and the container, a current collecting member for electrically connecting the plurality of fuel cell stacks, and an electric insulation An insulating member disposed between the fuel cell stacks adjacent to each other and extending in a direction in which the fuel cell extends, and is more thermally conductive than the insulating member. A heat conductive member formed of a high material, and the insulating member is in contact with one side and the other side of the fuel cell stack adjacent to each other The first insulating member and the second insulating member are arranged separately, and the heat conducting member is arranged between the first insulating member and the second insulating member, and the current collecting member and the heat insulating member are arranged. A third insulating member formed of an electrically insulating material is provided as a member independent of the heat insulating member between the conductive member and the conductive member.

  According to the present invention, the insulating member for insulating adjacent fuel cell stacks is divided into the first insulating member and the second insulating member, and the divided first insulating member and second insulating member are separated. A heat conduction member is disposed between the members, and the heat distribution of the fuel cells is equalized by the action of the heat conduction member. In order to electrically insulate the heat conducting member and the current collecting member that electrically connects the fuel cell stacks, the third insulating member is independent of the heat insulating member provided inside the container. Is provided. Therefore, it is possible to reliably insulate electrically by separating the heat conducting member and the current collecting member from each other by the third insulating member. Furthermore, since the insulating member is provided separately from the heat insulating member, after the fuel cell stack, the current collecting member, the heat conducting member, the first insulating member, and the second insulating member are assembled in the container, Since the insulating member can be easily inserted, the workability is excellent.

  In the fuel cell module according to the present invention, it is also preferable that the third insulating member is disposed apart from the current collecting member.

  According to this preferred aspect, even when the current collecting member undergoes thermal expansion or deformation during operation, it becomes difficult to contact the third insulating member, and the current collecting member and the heat conducting member are more reliably connected. It can be electrically isolated. Furthermore, the third insulating member can be easily inserted into the space between the current collecting member and the heat conducting member even at room temperature, and the workability is excellent. Furthermore, even if the heat conducting member undergoes thermal expansion, it becomes difficult to apply stress to the third insulating member and the current collecting member, and the occurrence of damage and the like can be suppressed.

  In the fuel cell module according to the present invention, it is also preferable that the third insulating member is disposed apart from the heat conducting member.

  According to this preferred aspect, even when the heat conducting member undergoes thermal expansion or deformation during operation, it becomes difficult to contact the third insulating member, and the current collecting member and the heat conducting member are more reliably connected. It can be electrically isolated. Moreover, even if the heat conducting member undergoes thermal expansion, it can be avoided that the third insulating member is pressed against the current collecting member, and damage to the current collecting member can be suppressed. Furthermore, the third insulating member can be easily inserted into the space between the current collecting member and the heat conducting member even at room temperature, and the workability is excellent. Furthermore, even if the heat conducting member undergoes thermal expansion, it becomes difficult to apply stress to the insulating member or the current collecting member, and the occurrence of damage or the like can be suppressed.

  Moreover, in a fuel cell provided with the fuel cell module according to the present invention, a fuel cell having the above-described effects can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a schematic perspective view in which the fuel cell module FC according to this embodiment is partially broken. The fuel cell module FC is configured as a device for generating electric power by causing an electrochemical reaction between fuel gas and air (oxidant gas).

  The fuel cell module FC includes a fuel cell 2, current collecting members 3 and 4, a current collecting rod 5, an air header 6, an air supply pipe 7, a module container 8, an insulating heat insulating member 9, and a heat insulating member. 10.

The fuel battery cells 2 are configured as fuel battery cell stacks (not explicitly shown in FIG. 1) for every 12 of the 2 rows × 6 rows, and are housed in the module container 8. Each fuel cell 2 has a bottomed cylindrical shape, and is made of a ceramic material and forms a multilayer structure of an air electrode, a solid oxide electrolyte, and a fuel electrode from the inside to the outside of the cylinder. When air is in contact with the inner wall of the fuel cell 2, that is, the air electrode, and fuel gas is in contact with the outer wall, that is, the fuel electrode, O ²⁻ ions move in the cell to cause an electrochemical reaction, and there is a potential difference between the air electrode and the fuel electrode. As a result, electricity is generated. The electricity generated by the fuel cell 2 is collected by the current collecting members 3 and 4 and taken out by the current collecting rod 5.

  The air supplied to each fuel cell 2 is supplied by distributing the air supplied to the air header 6 through the air supply pipe 7. In the present embodiment, three air headers 6 are provided, and an air supply pipe 7 is connected to each air header 6. The upstream side of the air supply pipe 7 is connected to an air supply source.

  The air header 6 serves to temporarily store and raise the temperature of air supplied to each fuel battery cell 2 and also to distribute air to each fuel battery cell 2. The air header 6 is also for distributing the flow path of the air supplied to each fuel cell 2 to a plurality of systems according to the number of the fuel cells 2, so that the air header 6 corresponds to the number of the fuel cells 2. The placement quantity is increased or decreased.

  The fuel gas supplied to each fuel cell 2 is supplied from below each fuel cell 2 (details will be described later).

  The fuel cell 2, the current collecting members 3 and 4, and the air header 6 are accommodated in a rectangular parallelepiped module container 8. The module container 8 is made of a heat-resistant alloy material such as Inconel or stainless steel because it becomes hot during operation. Moreover, it has a sealed structure in order to prevent fuel gas and air from leaking outside. Inside the module container 8, an insulating heat insulating member 9 is provided to insulate the fuel cell 2 and the module container 8 and keep the inside of the module container 8 warm. The insulating heat insulating member 9 is made of alumina fiber or the like. The module container 8 is further entirely covered with a heat insulating member 10 in order to keep the operating temperature stable.

  Then, the arrangement | positioning aspect of the fuel cell 2 is demonstrated, referring FIG. FIG. 2 is a cross-sectional view in the direction in which the fuel cell 2 side is seen from the air header 6 side in FIG. The fuel cell assembly 21 includes a plurality of fuel cell stacks 21a, 21b, and 21c. Each fuel cell stack 21a, 21b, 21c has 12 fuel cells 2, and each fuel cell 2 is arranged in 2 rows (x direction in the figure) × 6 rows (y direction in the figure). Has been.

  Each fuel cell 2 has a bottomed cylindrical shape, and is arranged with its opening 2a facing the air header 6 side. Each fuel cell 2 is electrically connected in 2 parallel × 6 series via an inter-cell current collecting member 13 and a conductive cell connecting member 14. The number and arrangement of the fuel cells 2 are appropriately selected according to the power generation capacity and the like.

  The fuel cell stacks 21a, 21b, and 21c are arranged in three rows (in the x direction in the figure) at a predetermined interval, and constitute a fuel cell assembly 21 having 36 fuel cells 2. ing. Each of the fuel cell stacks 21a, 21b, and 21c is electrically connected in series via the current collecting member 3. The current collecting member 4 is connected to the ends of the fuel cell stacks 21a, 21c arranged at both ends of the fuel cell stacks 21a, 21b, 21c connected in series in this way. Since the current collecting member 4 is connected to the current collecting rod 5, electric power can be taken out through the current collecting rod 5.

  Each fuel cell stack 21a, 21b, 21c has a pair of insulating plates 16 (first insulating member, second insulating member) such that the fuel cells 2 are in contact with a pair of side surfaces arranged in six rows. Are arranged opposite to each other at a predetermined interval so that the heat conducting plate 15 can be arranged therebetween. Further, a heat conduction plate 15 (heat conduction member) is disposed between adjacent insulating plates 16. A heat conducting plate 15 is also disposed between the fuel cell stacks 21a and 21c and the insulating heat insulating member 9. An insulating rod 11 (third insulating member) is disposed between the heat conducting plate 15 and the current collecting members 3 and 4.

  By arranging the heat conduction plate 15 in this way, even when the temperature of the fuel cell 2 is partially increased locally, heat easily moves from the high temperature portion to the low temperature portion via the heat conduction plate 15. Thus, the temperature distribution of the fuel cell 2 can be made uniform.

  Further, as described above, the insulating plate 16 and the insulating rod 11 are arranged, so that the electrical insulation between the heat conducting plate 15 and the fuel cell 2 and the heat conducting plate 15 and the current collecting members 3 and 4 Electrical insulation is ensured.

  Subsequently, an arrangement mode of the fuel cells 2 and a supply mode of the fuel gas and air will be described with reference to FIG. FIG. 3 is a longitudinal sectional view of the fuel cell module FC and shows the inside of the module container 8.

  As shown in FIG. 3, a fuel gas dispersion chamber 17 for uniformly dispersing the fuel gas introduced into the module container 8 is disposed below the module container 8. In the fuel gas dispersion chamber 17, a pre-dispersion plate 18 for pre-dispersing the fuel gas is disposed. The preliminary dispersion plate 18 is made of alumina, for example, and the fuel gas vent holes 19 are uniformly formed. Further, a fuel gas dispersion material 30 made of, for example, Ni foam is disposed above the preliminary dispersion plate 18. A fuel gas supply pipe 22 is provided on the upstream side (lower side in the figure) of the fuel gas dispersion chamber 17, and the upstream side of the fuel gas supply pipe 22 is connected to a fuel gas supply source. Further, a fuel gas dispersion plate 23 is provided between the module container 8 and the fuel gas dispersion chamber 17 to allow the fuel gas to flow from the fuel gas dispersion chamber 17 to the module container 8. The fuel gas distribution plate 23 has a plurality of fuel gas supply holes 24 formed therein.

  In addition, a plurality of air introduction pipes 25 for introducing air into the air electrode of the fuel cell 2 are connected to the air header 6 disposed above the fuel cell assembly 21. The air introduction pipe 25 is inserted into the pipe of the fuel cell 2, and its lower end extends to the vicinity of the bottom surface of the fuel battery cell 2.

  In the module container 8, a rectangular partition plate 26 formed along the direction perpendicular to the longitudinal direction of the fuel cell 2 is provided. The partition plate 26 is formed by laminating alumina fibers into a blanket shape. In the module container 8, a combustion chamber 27 is formed on the upper side partitioned by the partition plate 26, and a power generation chamber 28 is formed on the lower side. Here, the combustion chamber 27 mixes and burns surplus fuel gas that has not contributed to the reaction in the power generation chamber 28 and surplus air that has not contributed to the reaction in the cylinder of each fuel cell 2. Space. The power generation chamber 28 is a space for bringing the fuel gas introduced from the fuel gas supply hole 24 into contact with each fuel cell 2 and generating an electrochemical reaction with the air flowing in the pipe of each fuel cell 2 to generate power. It is.

  The partition plate 26 is inserted with a plurality of cylindrical fuel gas discharge pipes (not shown) made of alumina, for example, for discharging the remaining fuel gas from the power generation chamber 28 to the combustion chamber 27. Therefore, a plurality of gas discharge holes for allowing the fuel gas to pass from the power generation chamber 28 to the combustion chamber 27 are formed in the partition plate 26.

  FIG. 4 is a partially enlarged view showing a planar part of the fuel cell module according to the present invention. As shown in FIG. 4, the inter-stack current collecting member 4 is provided on the inner surface of the insulating heat insulating member 11. In addition, the heat conducting plate 15 disposed between the fuel cell stacks 21a and 21b is separated from the current collecting member 3 and is sandwiched by the insulating plates 16 from both sides. At the end of the insulating plate 16, a locking portion 16 a that protrudes outward is formed. The engaging portion 16a passes through the slit 3a formed in the current collecting member 3 and is fitted into the recessed portion 9a formed in the insulating heat insulating member 9, whereby the insulating plate 16 is fixed to the insulating heat insulating member 9. ing.

  A space S is formed in a region surrounded by the current collecting member 3, end portions of the heat conducting plate 15, and the insulating plates 16, and the insulating rod 11 is inserted into the space S. The insulating rod 11 is made of a ceramic tube such as alumina having an outer diameter smaller than the distance between the current collecting member 3 and the end portion of the heat conducting plate 15. The end portion of the heat conductive plate 15 and the insulating rod 11 are spaced apart. Further, the insulating rod 11 and the current collecting member 3 are also spaced apart. By disposing the insulating rod 11 in the space S described above, it is possible to stably insulate while maintaining the distance between the heat conductive plate 15 and the current collecting member 3 at the time of assembly at normal temperature or during transportation. Further, during operation, even when the heat conducting plate 15 and the current collecting member 3 are thermally expanded or deformed, they can be prevented from coming into contact with each other. Furthermore, the insulating rod 11 is arranged separately from at least one of the heat conducting member 15 and the current collecting member 3, and even when the heat conducting plate 15 is thermally expanded during operation, the insulating rod 11 is caused by the thermal expansion. It is possible to prevent the generation of stress.

  Next, the configuration of the fuel cell FCS using the fuel cell module FC will be described with reference to FIG. FIG. 5 is a block diagram showing the configuration of the fuel cell FCS. As shown in FIG. 5, the fuel cell FCS includes a fuel cell module FC, a fuel supply unit FP, an air supply unit AP, a water supply unit WP, a power extraction unit EP, and a control unit CS. . The fuel supply unit FP, the air supply unit AP, the water supply unit WP, and the power extraction unit EP constitute an auxiliary device AD of the fuel cell FCS.

  The fuel supply unit FP is a part that supplies fuel gas from a city gas pipe as a fuel supply source to the fuel cell module FC, and includes a fuel pump and an electromagnetic valve. The fuel gas supplied from the fuel supply unit FP is sent out to the fuel gas supply pipe 22.

  The air supply unit AP is a part that supplies air from the atmosphere as an air supply source to the fuel cell module FC, and includes an air blower and an electromagnetic valve. Air supplied from the air supply unit AP is sent out to the air supply pipe 7.

  The water supply unit WP is a part that supplies water to the solid oxide fuel cell module 1 from a water pipe as a water supply source, and includes a water pump and a solenoid valve. The water supplied from the water supply unit WP is sent out as water vapor inside the fuel cell module FC.

  The power extraction unit EP is a part that extracts electric power from the fuel cell module FC, and includes a power conversion device such as an inverter. The power extraction unit EP is connected to the current collecting rod 5 and is configured to send the converted power to a power supply destination.

  The control unit CS is a unit for controlling each of the fuel supply unit FP, the air supply unit AP, the auxiliary device AD, and the power extraction unit EP, and includes a CPU and a ROM. The operation of the fuel cell module FC is executed based on an instruction signal from the control unit CS.

  The operation of the fuel cell FCS configured as described above will be described. The power generation chamber 28 is heated to a temperature (700 to 1000 ° C.) at which an electrochemical reaction occurs. Air is supplied from the air supply unit AP to the air supply pipe 7 and stored in the air header 6. The stored air flows downward in the plurality of air introduction pipes 25 and flows out into the cylinder of the fuel cell 2 from the lower end. The outflowed air flows upward in the cylinder of the fuel battery cell 2. At this time, the air is brought into contact with the air electrode and subjected to the reaction. The air not consumed by the reaction reaches the combustion chamber 27 from the opening 2 a of the fuel cell 2.

  Further, the fuel gas is supplied from the fuel supply unit FP to the fuel gas supply pipe 22 and stored in the fuel gas dispersion chamber 17. The stored fuel gas is introduced into the power generation chamber 28 from a plurality of fuel gas supply holes 24 formed in the fuel gas dispersion plate 23, and flows upward while surrounding each fuel cell 2 in the power generation chamber 28. At this time, the fuel gas is brought into contact with the fuel electrode for reaction. The fuel gas not consumed by the reaction reaches the combustion chamber 27 through a fuel gas discharge pipe (not shown) of the partition plate 26.

  The remaining fuel gas and the remaining air that have reached the combustion chamber 27 are combusted using a predetermined ignition device, and exhaust gas is discharged out of the combustion chamber 27 from an exhaust gas pipe connected to the upper wall of the module container 8. Is done. Since this exhaust gas becomes high temperature, it is used as a heat source for heating the power generation chamber 28.

  The preferred embodiment of the present invention has been described in detail above, but the present invention is not limited to the above embodiment. For example, in the above-described embodiment, the fuel gas discharge pipe is used as the fuel gas discharge means for allowing the remaining combustion gas to flow from the power generation chamber 28 to the combustion chamber 27. However, the fuel gas discharge having only the holes formed in the partition plate 26 is used. A hole may be used.

It is the schematic perspective view which fractured partially the fuel cell module concerning this embodiment. FIG. 2 is a cross-sectional view in a direction in which the fuel cell side is seen from the air header side in FIG. 1. It is a longitudinal cross-sectional view of a fuel cell module. It is the elements on larger scale of a fuel cell module. It is a block diagram which shows the structure of a fuel cell.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Fuel cell, 3, 4 ... Current collection member, 5 ... Current collection rod, 6 ... Air header, 7 ... Air supply pipe, 8 ... Module container, 9 ... Insulation heat insulation member, 10 ... Heat insulation member, 21 ... Fuel Battery cell assembly 25 ... Air introduction pipe 26 ... Partition plate 27 ... Combustion chamber 28 ... Power generation chamber 29 ... Fuel gas discharge hole FC ... Fuel cell module FCS ... Fuel cell

Claims (4)

A plurality of fuel cell stacks formed by electrically connecting a plurality of fuel cells operated by fuel gas and oxidant gas; and
A container for housing the plurality of fuel cell stacks;
A heat insulating member disposed between the plurality of fuel cell stacks and the container;
A current collecting member for electrically connecting the plurality of fuel cell stacks;
An insulating member that is formed of a material having electrical insulation properties and disposed between the fuel cell stacks adjacent to each other;
A heat conducting member extending along a direction in which the fuel cell extends and formed of a material having a higher thermal conductivity than the insulating member, and
The insulating member is divided into a first insulating member and a second insulating member so as to be in contact with one side and the other side of the fuel cell stack adjacent to each other,
The heat conducting member is disposed between the first insulating member and the second insulating member,
A fuel cell module comprising a third insulating member formed of an electrically insulating material as a member independent of the heat insulating member between the current collecting member and the heat conducting member.   2. The fuel cell module according to claim 1, wherein the third insulating member is spaced apart from the current collecting member. 3.   3. The fuel cell module according to claim 1, wherein the third insulating member is disposed separately from the heat conducting member.   A fuel cell comprising the fuel cell module according to claim 1.

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