JP3943775B2 - Base tube for fuel cell and fuel cell module - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel cell base tube and a fuel cell that improve gas permeability while maintaining the strength of the base tube, improve power generation efficiency, reduce module manufacturing costs, and improve output density. Regarding modules.
[0002]
[Background]
A schematic structure of a conventional cylindrical solid electrolyte fuel cell module is shown in FIG. 7 is a schematic diagram of the cell tube portion, and FIG. 8 is a schematic diagram of the structure of the cell tube.
[0003]
As shown in FIG. 6, a top plate 02, an upper tube plate 03, and a lower tube plate 04 are disposed in a module body 01 surrounded by a heat insulating material, and a battery chamber is disposed below the lower tube plate 04. 01a is formed.
On the other hand, a fuel supply chamber 05 is formed between the top plate 02 and the upper tube plate 03 of the module body 01. A fuel discharge chamber 06 is formed between the upper tube plate 03 and the lower tube plate 04.
An outer pipe 07 that communicates the fuel supply chamber 05 and the outside of the module main body 01 is connected to the top plate 02 of the fuel supply chamber 05 through the module main body 01. An inner tube 08 that penetrates the lower tube plate 04 is disposed inside the outer tube 07 so as to communicate the fuel discharge chamber 06 and the outside of the module main body 01.
[0004]
In the lower tube sheet 04, a cell tube 010 formed by forming a single cell membrane (not shown) on the outer peripheral surface has an upper end positioned in the fuel discharge chamber 06 and a lower side is a battery chamber of the module body 01. Through-holes are supported so as to be positioned within 01a.
Inside the cell tube 010, a fuel injection pipe 011 penetrating the upper tube plate 03 is disposed so as to communicate the inside lower side of the cell tube 010 with the inside of the fuel supply chamber 05.
[0005]
Inside the fuel injection pipe 011, a current collecting rod 012 having an upper end positioned in the fuel supply chamber 05 and a lower end positioned near the lower end of the cell tube 010 is disposed. The lower end of the current collecting rod 012 is electrically connected to the unit cell membrane. The lower end of the cell tube 010 is closed by a seal cap 013 provided with a current collecting member 013a. The upper end of the current collecting rod 012 is electrically connected to the outside of the module body 01 through a nickel current collecting member 013a and a conductive rod 014.
On the other hand, a current collector connector 015 that is electrically connected to the unit cell membrane is attached to the upper end of the cell tube 010, and the current collector connector 015 is connected to the other cell tube 01 and the current collector connector 015. Connected in series.
[0006]
A porous ceramic partition plate 016 is provided below the battery chamber 01a of the module body 01. An air preheater 017 that communicates with the battery chamber 01a through the partition plate 016 is provided below the partition plate 016.
An air supply pipe 018 and an air discharge pipe 019 communicating with the outside of the module main body 01 are connected to the air preheater 017. Here, after the air supplied to the battery chamber 01a is used for power generation, it is discharged from the air discharge pipe 019a to the air preheater 017 as battery chamber exhaust air. In the air preheater 017, heat exchange is performed between the battery chamber exhaust air and the supply air 021, and the air is preheated and supplied to the lower part of the partition plate 016, and at the same time, the exhaust air is cooled and passed through the air exhaust pipe 019. Drain out of the module.
[0007]
In the cell tube 01, as shown in FIGS. 7 to 9, the fuel electrode 032a, the electrolyte 032b, and the air electrode 032c are sequentially laminated on the surface of the base tube 031, and further, the fuel electrode side electrode and the air side electrode are connected. A plurality of unit cell films 032 are formed in a horizontal stripe shape by laminating these conductive connecting materials (not shown).
[0008]
Next, the operation of the cylindrical solid electrolyte fuel cell module having such a structure will be described.
The inside of the battery chamber 01a of the module main body 01 is heated to an operating temperature (about 900 to 1000 ° C.), fuel gas 020 such as hydrogen is supplied from the outer pipe 07, and air 021 which is oxidant gas is supplied from the air supply pipe 018. Supply.
The fuel gas 020 supplied via the outer pipe 07 flows from the fuel supply chamber 05 to the lower end side of the cell tube 010 via the injection pipe 011.
On the other hand, the air 021 that has passed through the partition plate 016 flows into the battery chamber 01a through the air preheating chamber 017.
[0009]
When the fuel 020 passes through the porous base tube 031 and is supplied to a single cell membrane (not shown), and the air (oxygen) 021 comes into contact with the single cell membrane 035, the single cell membrane 035 is fuel and air (oxygen). ) To generate an electric power, and the electric power is sent to the outside through the current collecting member 013a, the conductive rod 014, the current collecting member 013a, and the conductive rod 014.
[0010]
The remaining fuel gas 022 after being used for power generation flows into the fuel discharge chamber 06 from the upper end of the cell tube 010 and is discharged to the outside through the inner pipe 08, while The remaining air 023 is discharged to the outside through the air discharge pipe 019a.
[0011]
[Problems to be solved by the invention]
In the fuel cell module, the base tube 031 and the electrodes constituting the cell tube 010 use a porous body in order to smoothly supply and exhaust gas.
A conceptual diagram of the operating state is shown in FIGS.
As shown in these drawings, the movement of the gas in the porous body of the base tube 031 is due to concentration diffusion, but the gas is once injected into the tube through the injection tube 011 and then reversed, and the fuel is used for power generation. The remaining fuel gas 022 is discharged from the opening, but when the operating current density and the fuel utilization rate of the fuel cell are high, the fuel transport in the base tube 031 and the fuel electrode 032a is performed downstream of the fuel supply (opening Side), the diffusion limit is reached, and there is a problem that fuel supply to the reaction site stagnate and it becomes difficult to continue operation.
[0012]
For this reason, in order to improve the gas transport performance, it has been proposed to improve the porosity by thinning the porous material such as the base tube and changing the material. There is a problem that the strength is restricted to maintain strength.
[0013]
As described above, the conventional base tube has a problem that the upper limit of the operating current density and the fuel utilization rate of the fuel cell is suppressed, which is an obstacle to downsizing and high efficiency.
[0014]
In the cylindrical solid electrolyte fuel cell module as described above, since the operating temperature is high (around 900 to 1100 ° C.), the top plate 02, the upper tube plate 03, and the lower tube disposed in the module main body 01. The material of the plate 04 needs to be made of a heat resistant alloy.
This is because the fuel supply / discharge pipes such as the injection pipe 011 are made of ceramics, so they are fragile and need to maintain soundness over a long period of time so that they will not crack or crack even if the temperature changes. Because there is.
In addition, the top plate 02, the upper tube plate 03, and the lower tube plate 04 have to be thick in consideration of durability so that distortion or the like does not occur, so that there is a problem that the manufacturing cost further increases. .
[0015]
Therefore, in view of the above problems, the present invention aims to improve the gas permeability while maintaining the strength of the base tube, improve the power generation efficiency, reduce the manufacturing cost of the module, and improve the output density. An object of the present invention is to provide a battery substrate tube and a fuel cell module.
[0016]
[Means for Solving the Problems]
The invention of [Claim 1] that solves the above-described problem is a cylindrical support that integrally fires a fuel electrode and an air electrode that constitute a cell tube for a fuel cell. Thus, a linear groove is provided.
[0018]
Invention [Claim 2], in claim 1, characterized in that the groove portion is formed Article number over the entire circumference.
[0022]
The invention of the fuel cell module of [Claim 3 ] provides the oxidant gas and the fuel gas to the cell tube formed by forming a single cell membrane on the outer peripheral surface of the battery chamber under the operating temperature environment. 3. A cylindrical solid electrolyte fuel cell module in which an oxidant gas and a fuel gas are electrochemically reacted to obtain electric power, wherein the substrate tube according to claim 1 or 2 is used for a fuel cell cell tube. It is characterized by that.
[0023]
The invention of the fuel cell module of [Claim 4 ] is characterized in that, in Claim 3 , a module body having a gas supply chamber, a gas discharge chamber, and a battery chamber therein, a plurality of cell tubes communicating with the gas supply chamber, An extraction pipe that communicates with the gas discharge chamber and is inserted into the cell tube and discharges the remaining gas after power generation.
[0024]
The invention of [Claim 5 ] is characterized in that, in Claim 4 , the supplied gas is a fuel gas.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a fuel cell substrate tube and a fuel cell module according to the present invention will be described below, but the present invention is not limited to these embodiments.
[0027]
[First Embodiment]
A first embodiment of the present invention will be described with reference to FIG.
FIG. 1 is a schematic view of a base tube for a fuel cell.
As shown in FIG. 1, a fuel cell substrate tube (hereinafter referred to as “substrate tube”) 11 according to the present embodiment is a cylindrical support that integrally fires a fuel electrode and an air electrode constituting a cell tube. It is a body and is provided with a linear groove portion 12a on the entire inner circumference over the axial direction.
[0028]
In the present embodiment, the groove 12a is provided over the entire circumference, but a plurality of grooves may be formed with appropriate intervals.
[0029]
As a result of the formation of the groove 12a, the thickness of the base tube 11 is reduced at the groove 12a, and the permeability of the fuel gas passing through the inside in the axial direction is improved.
Further, the strength can be maintained by forming the rib portion 12b.
Therefore, by forming the groove 12a, the permeation distance of the fuel gas can be shortened while maintaining the original function of the base tube as a support member for sintering, and the power generation efficiency on the downstream side of the conventional fuel is reduced. Can be prevented.
[0030]
[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIG.
FIG. 2 is a schematic view of a fuel cell substrate tube.
As shown in FIG. 2, the fuel cell base tube according to the present embodiment is different from the linear groove 12 of the first embodiment in that a spiral groove 13 is formed.
[0031]
In the present embodiment, the groove 13 is provided over the entire circumference, but a plurality of grooves 13 may be formed at appropriate intervals.
[0032]
As a result of the formation of the spiral groove 13, the thickness of the base tube is reduced at the spiral groove 13 portion, and the permeability of the fuel gas passing in the axial direction inside is improved.
Therefore, by forming the spiral groove 13 on the inner peripheral surface of the base tube like the inner peripheral surface of the rifle, the permeation distance of the fuel gas is maintained while maintaining the original function of the base tube as a support member for sintering. It can be shortened, and a decrease in power generation efficiency on the downstream side of the conventional fuel can be prevented.
[0033]
[Third Embodiment]
A third embodiment of the present invention will be described with reference to FIG.
FIG. 3 is a schematic view of a base tube for a fuel cell.
As shown in FIG. 3, the fuel cell base tube according to the present embodiment is different from the first and second embodiments in that the end of the base tube 11 supported by the tube plate in the fuel cell module. A plurality of fine holes 14 are formed in the vicinity.
The fine holes 14 may be formed before the base tube 11 is fired.
[0034]
In addition, the formation part of the said fine hole 14 should just be the exit vicinity of the cell of a fuel cell.
If the cell tube shown in FIG. 7 is suspended and an injection pipe 011 which is a gas supply pipe is provided inside to supply fuel gas and fuel is supplied by rising gas, the end on the tube plate 035 side is used. It is preferable to form the fine holes 14 in a region of 1/8 to 1/12 with respect to the axial direction.
[0035]
As a result of the formation of the fine holes 14, the fuel cell is smoothly supplied to the single cell membrane formed in the portion having the fine holes by passing through the fine holes 14.
Therefore, the formation of the fine holes 14 can improve the permeability of the fuel gas while maintaining the original function of the base tube as a support member for sintering, and can improve the power generation efficiency on the downstream side of the conventional fuel. A decrease can be prevented.
[0036]
[Fourth Embodiment]
A fourth embodiment of the present invention will be described with reference to FIG.
FIG. 4 is a schematic view of the fuel cell base tube installed in the module.
As shown in FIG. 4, the fuel cell base tube according to the present embodiment differs from the first to third embodiments in that the vicinity of the lower end supported by the tube plate in the fuel cell module is a tapered portion. It is set to 15.
As a result of the formation of the tapered portion 15, the thickness gradually decreases toward the end side, and as a result, the permeability of the passing fuel gas does not decrease, and gas can be supplied evenly.
[0037]
The portion where the taber portion 15 is formed may be in the vicinity of the outlet of the fuel cell. If the cell tube 22 shown in FIG. 4 is suspended from the lower tube plate 43 and an extraction tube 23 for extracting gas is provided therein, the end on the side where the seal cap 25 including the current collecting member 25a is provided. It is preferable to form the taber portion 15 in a region of 1/8 to 1/12 with respect to the axial direction.
Further, the thinner portion at the tip of the taper portion 15 is preferably as thin as possible with respect to the thickness of the cell tube, but it may be set to about 1/2 to 1/3 from the viewpoint of maintaining strength.
[0038]
This is because the thinning of the entire base tube causes a decrease in the strength of the entire cell. However, in the cell structure as shown in FIG. 7, the weight of the entire cell tube is added to the tapered portion, which is not preferable. Therefore, the fuel supply method is reversed from that shown in FIG. 7, the tube plate side is used as the fuel supply part, and the vicinity of the tip is used as the fuel gas outlet part. It is possible to reduce the thickness of the base tube.
The structure shown in FIG. 4 is a structure in which the cell tube is suspended, and only the seal cap 25 needs to be joined. Therefore, the taper portion is not added.
[0039]
[Fifth Embodiment]
A fifth embodiment of the present invention will be described with reference to FIG.
FIG. 5 is a schematic view of a module including the fuel cell substrate tube of FIG.
As shown in FIG. 5, the fuel cell module of the present embodiment is a cell tube formed by forming a cell membrane 21 on the outer peripheral surface of a battery chamber 33 under an operating temperature environment with air 31 and fuel gas 32. In the cylindrical solid electrolyte fuel cell module in which the air 31 and the fuel gas 32 are electrochemically reacted to obtain electric power by being supplied to the fuel gas supply chamber 35, a fuel gas supply chamber 35 and a fuel gas discharge chamber are provided therein. 36 and a battery chamber 33, a plurality of cell tubes 22 communicating with the fuel gas supply chamber 35, and communicating with the fuel gas discharge chamber 36 and inserted into the cell tube 22, And an extraction pipe 39 for discharging the remaining fuel gas 38.
[0040]
Details of the fuel cell module will be described below.
A top plate 41, an upper tube plate 42, and a lower tube plate 43 are disposed in the module main body 37 surrounded by a heat insulating material, and a battery chamber 33 is formed below the lower tube plate 43.
Further, a fuel supply chamber 35 for supplying the fuel gas 32 from the outside is formed between the upper tube plate 42 and the lower tube plate 43. On the other hand, a fuel discharge chamber 36 for remaining fuel gas 38 discharged from the cell tube 22 is formed between the top plate 41 and the upper tube plate 42 of the module body 37.
An outer tube 44 that connects the fuel discharge chamber 36 and the outside of the module main body 37 is connected to the top plate 41 of the fuel discharge chamber 36 through the module main body 37. Inside the outer tube 44, an inner tube 45 penetrating the lower tube plate 43 is disposed so as to communicate the fuel supply chamber 35 and the outside of the module body 37.
[0041]
In the lower tube plate 43, a cell tube 22 formed by forming a cell membrane (not shown) on the outer peripheral surface is positioned so that the upper end communicates with the inside of the fuel supply chamber 35, and the lower side is the module body. The through hole 37 is supported so as to be positioned in the battery chamber 33.
Inside the cell tube 22, a fuel discharge pipe 23 that penetrates the upper tube plate 42 is disposed so as to communicate the inside lower side of the cell tube 22 with the inside of the fuel discharge chamber 36.
[0042]
Inside the extraction pipe 23, a current collecting rod 24 having an upper end positioned in the fuel supply chamber 35 and a lower end positioned in the vicinity of the lower end of the cell tube 22 is disposed. The lower end of the current collecting rod 24 is connected to a current collecting member 25 that is electrically connected to the unit cell membrane and closes the lower end of the cell tube 22. The upper end of the current collecting rod 24 is electrically connected to the outside of the module main body 37 via a nickel current collecting member 46 and a conductive rod 47.
On the other hand, a current collector connector 48 that is electrically connected to the unit cell membrane is attached to the upper end of the cell tube 22, and the current collector connector 48 is connected to the other cell tube 22 and the current collector connector 48. Connected in series.
[0043]
A porous ceramic partition plate 51 is provided below the battery chamber 33 of the module body 37. An air preheater 52 that communicates with the battery chamber 33 through the partition plate 51 is provided below the partition plate 51.
The air preheater 52 is connected to an air supply pipe 53 and an air discharge pipe 55 that communicate with the outside of the module body 37. After the air supplied to the battery chamber 33 is used for power generation, it is discharged from the air discharge pipe 55a to the air preheater 52 as the battery chamber exhaust air 54. In the air preheater 52, heat exchange is performed between the battery chamber exhaust air 54 and the supply air 31, and the supply air 31 is preheated and supplied to the lower part of the partition plate 51. At the same time, the exhaust air 54 is cooled and air exhausted. It is discharged out of the module through the pipe 55.
Reference numeral 57 denotes a heat insulating material.
[0044]
Here, the composition constituting the cell tube 22 is not particularly limited. For example, a fuel electrode made of Ni-zirconia cermet on the surface of the base tube 11 made of calcia-stabilized zirconia (CSZ), and an electrolyte made of YSZ. , LaMnO _{3 and} other air side electrodes are sequentially laminated, and a conductive connecting material for connecting the fuel electrode side electrode and the air side electrode is further laminated to form a plurality of unit cell membranes 21 in a horizontal stripe shape. It is.
[0045]
Next, the operation of the cylindrical solid electrolyte fuel cell module having such a structure will be described.
[0046]
The inside of the battery chamber 33 of the module body 10 is heated to an operating temperature (about 900 to 1000 ° C.), and the element serving as the fuel introduction pipe supplies the fuel gas 32 such as hydrogen from the inner pipe 45 and oxidizes from the air supply pipe 53. Electric power is generated while supplying the air 31 as the agent gas.
The fuel gas 32 supplied through the fuel introduction inner pipe 45 flows into the inside through the opening of the cell tube 22 that opens into the fuel supply chamber 35.
The fuel gas 32 that has flowed into the cell tube 22 is used for the reaction, folded at the lower end, discharged to the fuel discharge chamber 36 through the extraction tube 23, and discharged to the outside through the outer tube 44.
The supplied fuel gas 32 is preheated by this double tube structure.
[0047]
Further, the exhausted air 54 after being used for power generation is discharged to the outside through the air discharge pipe 55.
[0048]
According to the present embodiment, unlike the configuration of the fuel cell module as shown in FIG. 6, the fuel supply chamber 35 is provided on the lower tube plate 43 side, so the fuel gas 32 supplied from the outside The lower tube sheet can be cooled.
[0049]
For example, by cooling the lower tube plate 43 by setting the temperature of the supplied fuel gas from room temperature to 500 ° C. (preferably 200 to 300 ° C.), it is not necessary to make the lower tube plate 43 a high-temperature resistant high-grade material. Since the workability becomes easy, it is possible to reduce the manufacturing cost of the module (cost reduction of about 1/3).
Therefore, according to the present embodiment, the output per unit cell area increases, the number of cells can be reduced, and the module can be downsized. As a result, the fuel cell device can be reduced in size and cost.
[0050]
In the present embodiment, the cell tube shown in FIG. 4 is disposed in the module. However, the present invention is not limited to this, and the cell tube including the base tube in FIGS. 1 to 3 is disposed. You may do it.
[0051]
Thus, according to the present invention, by changing the material of the base tube, besides improving the porosity, the gas permeability is improved while maintaining the strength of the base tube, the gas diffusion limit is improved, The power generation efficiency can be improved, the module manufacturing cost can be reduced, and the output density can be improved.
[0052]
In the present invention, the fuel supply is made in the cell tube and the air supply is made outside the cell tube. However, the present invention is not limited to this, and the air supply is made in the cell tube and the fuel supply is made outside the cell tube. It is good also as a structure of.
[0053]
【The invention's effect】
As described above, according to the invention of [Claim 1], it is a cylindrical support body that integrally fires the fuel electrode and the air electrode constituting the fuel cell cell tube, and is axially disposed on the inner peripheral surface. Since the straight groove portion is provided over this, the permeation distance of the fuel gas can be shortened while maintaining the original function of the base tube as a support member for sintering, and on the downstream side of the conventional fuel It is possible to prevent a decrease in power generation efficiency.
[0055]
The invention of [Claim 2 ] is that in Claim 1, the permeation distance of the fuel gas in which the groove is formed on the entire inner surface can be shortened and the portion can be increased, and the power generation efficiency is improved.
[0059]
The invention of the fuel cell module of [Claim 3 ] provides the oxidant gas and the fuel gas to the cell tube formed by forming a single cell membrane on the outer peripheral surface of the battery chamber under the operating temperature environment. 3. A cylindrical solid electrolyte fuel cell module in which an oxidant gas and a fuel gas are reacted electrochemically to obtain electric power, wherein the substrate tube according to claim 1 or 2 is used for a cell tube for a fuel cell. because, while maintaining the strength of the substrate tube to improve the gas permeability, improve gas diffusion limitations, it is possible to improve the power generation efficiency, it is possible to improve the reduction and power density of the manufacturing cost of the module it can.
[0060]
The invention of the fuel cell module of [Claim 4 ] is characterized in that, in Claim 3 , a module body having a gas supply chamber, a gas discharge chamber, and a battery chamber therein, a plurality of cell tubes communicating with the gas supply chamber, An extraction pipe that communicates with the gas discharge chamber and that is inserted into the cell tube and discharges the remaining gas after power generation, so that the lower tube sheet can be cooled with fuel gas supplied from the outside. It is possible to reduce the cost of the material of the tube sheet.
[0061]
The invention of [Claim 5 ] can constitute a fuel cell with high power generation efficiency by using fuel gas as the gas to be supplied in Claim 4 .
[Brief description of the drawings]
FIG. 1 is a schematic view of a fuel cell substrate tube according to a first embodiment.
FIG. 2 is a schematic view of a fuel cell substrate tube according to a second embodiment.
FIG. 3 is a schematic view of a base tube for a fuel cell according to a third embodiment.
FIG. 4 is a schematic view of a fuel cell cell tube according to a fourth embodiment.
FIG. 5 is a schematic view of a fuel cell module according to a fifth embodiment.
FIG. 6 is a schematic view of a conventional fuel cell module.
7 is a schematic view of the cell tube portion of FIG. 6;
FIG. 8 is a schematic structural view of a cell tube.
FIG. 9 is a schematic view of gas flow in a base tube.
[Explanation of symbols]
11 Substrate tube for fuel cell (substrate tube)
12a Linear groove portion 13 Spiral groove portion 14 Fine hole 15 Tapered portion 21 Cell membrane 22 Cell tube 23 Extraction tube 24 Current collecting rod 25 Current collecting member 31 Air 32 Fuel gas 33 Battery chamber 35 Fuel gas supply chamber 36 Fuel gas discharge Chamber 37 Module body 38 Remaining fuel gas 39 Extraction pipe

Claims (5)

A cylindrical support that integrally fires a fuel electrode and an air electrode that constitute a cell tube for a fuel cell, and is characterized in that a linear groove is provided on the inner peripheral surface in the axial direction. Battery substrate tube. In claim 1,
Fuel cell substrate tube, characterized in that the groove portion is formed Article number over the entire circumference. The oxidant gas and the fuel gas are electrochemically reacted by supplying the oxidant gas and the fuel gas to a cell tube formed with a single cell membrane on the outer peripheral surface of the battery chamber under the operating temperature environment. In the cylindrical solid electrolyte fuel cell module which is made to obtain electric power,
A fuel cell module comprising the substrate tube according to claim 1 or 2 as a cell tube for a fuel cell. In claim 3,
A module main body having a gas supply chamber, a gas discharge chamber, and a battery chamber inside, a plurality of cell tubes communicating with the gas supply chamber, and communicating with the gas discharge chamber and inserted into the cell tube, And an extraction pipe for discharging the residual gas of the fuel cell module. In claim 4,
A fuel cell module, wherein the gas to be supplied is a fuel gas.

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