JPH10228916A - Fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To be able to increase the output more by keeping the advantage of being the simple supply and discharge structure of each oxygen containing gas and fuel gas. SOLUTION: The supply opening si and the discharge opening so of the oxygen containing gas passages s is arranged each on the one opposite pair of end surfaces of the electrolyte layer 1, the supply opening fi and the discharge opening fo of the fuel gas passages f are arranged each on the other opposite pair of surfaces of the electrolyte layer 1, and the temperature difference restriction passage part P are prepared for making flow the fuel gas or the oxygen containing gas to restrict the temperature difference of the both direction of the electrolyte layer 1, being composed so as to have smaller gas flow resistance than that of the pliable conductive material 5, at the position separated and parallel with the electrolyte layer 1 to the fuel electrode 3 or the oxygen electrode 2, between passage part 4 and the fuel electrode 3 or the passage part 4 and the oxygen electrode 2, both filled with the pliable conductive material 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a fuel cell system comprising: a plurality of rectangular plate-like electrolyte layers having an oxygen electrode on one surface and a fuel electrode on the other surface; A passage forming member having conductivity, which forms a passage, and defines a fuel gas passage on the side facing the fuel electrode,
In a state of being located between the adjacent electrolyte layers, they are provided side by side in the thickness direction at an interval from each other, and the supply opening and the discharge opening of the oxygen-containing gas flow path are one pair of one of the opposing electrolyte layers. A supply opening and a discharge opening of the fuel gas flow path are separately provided at each of the edge portions,
In the electrolyte layer, provided separately at each of the other pair of opposite edge portions, between the flow path forming member and the fuel electrode, or between the flow path forming member and the oxygen electrode, The present invention relates to a fuel cell filled with a flexible conductive material formed so as to allow the flow of gas.

[0002]

2. Description of the Related Art In such a fuel cell, a plurality of rectangular plate-shaped electrolyte layers are formed in an aggregate in which the electrolyte layers are arranged in the thickness direction.
The supply opening and the discharge opening of the oxygen-containing gas flow path are respectively located on one of a pair of facing surfaces of the two surface portions, and the fuel gas flow passage is provided on the other of the pair of facing surfaces. Each supply opening and discharge opening will be located separately. Therefore, a configuration for supplying the oxygen-containing gas to each of the oxygen-containing gas channels, a configuration for discharging the oxygen-containing gas from each of the oxygen-containing gas channels, and a configuration for supplying the fuel gas to each of the fuel gas channels. Also, there is an advantage that the configuration for discharging the fuel gas from each of the fuel gas passages is simplified. Then, between the flow path forming member and the fuel electrode, or between the flow path forming member and the oxygen electrode, is filled with a flexible conductive material formed so as to allow gas to flow therethrough. While passing the fuel gas or oxygen-containing gas through the conductive conductive material, the flexible conductive material connects the flow path forming member and the fuel electrode or the flow path forming member and the oxygen electrode in a conductive state. ing.

Conventionally, in such a fuel cell, the fuel gas flow path is formed such that the fuel gas flows linearly from the supply opening to the discharge opening over the entire width of the flow path in the direction along the edge of the electrolyte layer. Or formed to flow in a substantially straight line,
The oxygen-containing gas flow path is such that the oxygen-containing gas flows linearly or substantially linearly from the supply opening toward the discharge opening over the entire width of the flow path in the direction along the edge of the electrolyte layer. Had formed. That is, the direction in which the straight or substantially straight flow path of the fuel gas flow path is formed is orthogonal to the direction in which the straight or substantially straight flow path of the oxygen-containing gas flow path is formed.

[0004]

In the process of flowing the fuel gas through the fuel gas passage, hydrogen in the fuel gas undergoes an electrode reaction, so that the content of hydrogen in the fuel gas is reduced. The lower the flow path becomes, the smaller the oxygen-containing gas flows in the oxygen-containing gas flow path, and the oxygen in the oxygen-containing gas causes an electrode reaction. Is smaller on the lower side of the flow path of the oxygen-containing gas.

Therefore, in the conventional fuel cell, the fuel gas flows in the fuel gas flow path linearly or substantially linearly from the supply opening to the discharge opening over the entire width of the flow path. The amount of the electrode reaction caused by hydrogen in the fuel gas decreases along the direction from the supply opening to the discharge opening of the fuel gas flow path toward the discharge opening.
On the other hand, the oxygen-containing gas flows in the oxygen-containing gas flow path linearly or substantially linearly from the supply opening to the discharge opening over the entire width of the flow path. The amount of electrode reaction caused by the discharge decreases along the direction from the supply opening to the discharge opening of the oxygen-containing gas flow path toward the discharge opening.

The electrode reaction caused by hydrogen and oxygen is an exothermic reaction. As the amount of the electrode reaction increases, the amount of heat generated increases. The temperature of the rectangular three-layer plate formed by the fuel electrode and the oxygen electrode increases. Therefore, conventionally, although changing depending on the flow rate of the fuel gas or the oxygen-containing gas, basically, due to the fuel gas flowing through the fuel gas flow path, the discharge opening from the supply opening of the fuel gas flow path. Along the direction toward, a temperature distribution that becomes lower toward the discharge opening side occurs, and, due to the oxygen-containing gas flowing through the oxygen-containing gas flow path, the temperature distribution decreases from the supply opening of the oxygen-containing gas flow path. Along the direction toward the opening, there occurs a temperature distribution that becomes lower toward the discharge opening. Therefore, in the surface direction of the three-layer plate, the direction in which the temperature changes due to the fuel gas and the direction in which the temperature changes due to the oxygen-containing gas are orthogonal to each other, as shown in FIG. The temperature distribution in the plane direction of the three-layer plate Ce is generally formed by the edge where the supply opening fi of the fuel gas flow path is located and the edge where the supply opening si of the oxygen-containing gas flow path is located. The corners formed by the edge where the discharge opening fo of the fuel gas flow path is located and the edge where the discharge opening so of the oxygen-containing gas flow path s is located become closer to the corner of the fuel gas flow path s. The temperature distribution becomes complicated such that the temperature decreases, and the temperature difference in the surface direction of the three-layer plate Ce increases. In FIG. 10, T
₁ , T ₂ , T _3, ..., T ₉ indicate isotherms, and the larger the subscript number, the lower the temperature.

[0007] When the flow rate of the fuel gas or the oxygen-containing gas increases, heat generated by the electrode reaction is transferred to the downstream side, and a temperature distribution may become higher toward the discharge opening side. Also, in the surface direction of the three-layer plate, the direction in which the temperature changes due to the fuel gas and the direction in which the temperature changes due to the oxygen-containing gas are orthogonal to each other. The temperature distribution in the direction is
The temperature distribution becomes complicated, and the temperature difference in the plane direction of the three-layer plate increases.

[0008] When the temperature difference in the plane direction of the three-layer plate becomes large, internal stress is easily generated in the three-layer plate. On the other hand, as the output of the fuel cell increases, the amount of electrode reaction increases. In conventional fuel cells,
As the output of the fuel cell increases, the internal stress of the three-layer plate increases, which may lead to a decrease in durability.
Therefore, conventionally, even if the output of the fuel cell is increased, there is a limit in terms of durability, and there is room for improvement in increasing the output.

The present invention has been made in view of the above circumstances, and has as its object to supply and discharge an oxygen-containing gas to each of the oxygen-containing gas flow paths, and to provide a fuel gas to each of the fuel gas flow paths. The advantage of the simplicity of the supply and discharge arrangement lies in the fact that the output can be further increased while maintaining it.

[0010]

According to the first aspect of the present invention, the flow resistance of the gas in the temperature difference suppressing flow portion is smaller than that of the flexible conductive material, and the gas flows through the temperature difference suppressing portion. Flow through the flow passage portion more easily than in the flexible conductor. Therefore, for example, when the flexible conductive material is filled between the flow path forming member and the fuel electrode, the fuel gas supplied to the supply opening flows through the flexible conductive material toward the discharge opening. It flows through the inside of the temperature difference suppressing flow portion more easily than in a straight line so as to suppress the temperature difference in the surface direction of the electrolyte layer by the guiding action. The fuel gas flowing through the temperature difference suppression flow passage penetrates and diffuses into the flexible conductive material, and contacts the entire surface of the fuel electrode. Alternatively, in the case where the flexible conductive material is filled between the flow path forming member and the oxygen electrode, the oxygen-containing gas supplied to the supply opening flows straight through the flexible conductive material toward the discharge opening. It flows through the temperature difference suppressing flow portion so as to suppress the temperature difference in the surface direction in the electrolyte layer by the guiding action thereof more easily than flowing in the shape. The oxygen-containing gas flowing through the temperature difference suppressing flow passage penetrates and diffuses into the flexible conductive material, and contacts the entire surface of the oxygen electrode.

Therefore, the oxygen-containing gas or the fuel gas is caused to flow so as to suppress the temperature difference in the surface direction in the three-layer plate, so that the temperature difference in the surface direction in the three-layer plate can be suppressed. Therefore, the advantage that the supply configuration and the discharge configuration of the oxygen-containing gas to each of the oxygen-containing gas passages and the supply configuration and the discharge configuration of the fuel gas to each of the fuel gas passages are simple is maintained as it is. However, the output can be further increased.

According to the second aspect of the present invention, since the temperature difference suppressing flow-through portion is formed by the gap provided in the flexible conductive material, the gas is supplied to the flexible conductive material. It flows through the temperature difference suppressing flow portion more easily than when it flows straight through the inside toward the discharge opening. Therefore, the temperature difference in the plane direction in the three-layer plate can be further suppressed, and the output can be further increased.

According to the third aspect of the present invention, the flexible conductive material is divided in the direction in which the electrolyte layers are arranged so that each portion has a void portion constituting a void portion. It is configured such that a void portion is formed by overlapping the formed portions. That is, each of the portions divided in the direction in which the electrolyte layers are arranged has a simple shape such as having a concave portion as a void portion and a flat portion closing the concave portion. Incidentally, the flexible conductive material can be formed as an integral body, but in this case, it is necessary to form a tunnel-shaped void, and the manufacturing method becomes complicated. Therefore, the manufacturing cost of the flexible conductive material having the void can be reduced, and the cost for implementing the present invention can be reduced.

According to the fourth aspect of the present invention, the temperature difference suppressing flow portion makes the fuel gas or the oxygen-containing gas make a U-turn before the discharge opening and before the supply opening, respectively. Since it is configured to flow between the supply opening and the discharge opening in a state of at least 1.5 reciprocations, the temperature difference suppressing flow portion has at least two outgoing portions and one flow portion. Of the return route.

For example, when the flexible conductive material is filled between the flow path forming member and the fuel electrode, the fuel gas supplied from the supply opening is guided by the temperature difference suppressing flow passage. After flowing back and forth between the supply opening and the discharge opening a predetermined number of times, the liquid is discharged from the discharge opening. In the process of flowing the fuel gas through the temperature difference suppression flow passage, hydrogen in the fuel gas causes an electrode reaction, so that the lower part of the flow path is included in the forward path and the return path constituting the temperature difference suppression flow passage. The fuel gas flowing through the one located on the side has a lower hydrogen content. Therefore, at the fuel electrode, in the direction orthogonal to the direction connecting the supply opening and the discharge opening, the fuel gas is supplied from each of the outward path and the return path constituting the temperature difference suppressing flow passage. Since the hydrogen content in the fuel gas flowing through each of the forward path portion and the return path portion is different, the variation in the amount of electrode reaction in the surface direction of the fuel electrode can be reduced.

The same applies to the case where the flexible conductive material is filled between the flow path forming member and the oxygen electrode, and the variation in the amount of electrode reaction in the plane direction of the oxygen electrode can be reduced. Therefore, the temperature difference in the plane direction in the three-layer plate can be suppressed.

By the way, in the case where the hydrocarbon-based gas in the fuel gas supplied from the supply opening to the fuel gas passage is reformed into a gas containing hydrogen gas in the fuel gas passage. The reforming reaction tends to proceed remarkably when the fuel gas flows into the fuel gas passage. Incidentally, the reforming reaction is an endothermic reaction. When the hydrocarbon-based gas is, for example, methane, the reforming reaction is as follows. CH ₄ + 2H ₂ O → 4H ₂ + CO ₂

According to the fifth aspect of the present invention, the fuel gas flows intensively into a part of the fuel gas flow path as viewed in the direction in which the electrolyte layers are arranged in the fuel gas flow path by the guide of the temperature difference suppressing flow portion. , Through one part and then through the other part. Then, the reforming reaction intensively proceeds in the part of the fuel gas flow path, and the part is cooled by the endothermic effect of the reforming reaction to lower the temperature. Therefore, the part is the highest temperature part where the temperature of the three-layer plate is highest in the conventional fuel cell,
If it is configured to be located at a portion where the electrolyte layers are overlapped in the arrangement direction, the temperature of the highest temperature portion can be reduced. Therefore, the temperature difference in the plane direction of the three-layer plate can be suppressed.

For example, in a conventional fuel cell, FIG.
When the temperature distribution as shown in the above occurs, the highest temperature portion is, in the surface direction of the three-layer plate, the edge where the supply opening of the fuel gas passage is located and the supply opening of the oxygen-containing gas passage. Is formed at a corner-side portion formed by the end edge at which is located, so that the portion is located at the corner-side portion. Further, as the flow rate of the oxygen-containing gas flowing through the oxygen-containing gas flow path increases, the temperature distribution increases along the direction from the supply opening to the discharge opening of the oxygen-containing gas flow path toward the discharge opening. The highest temperature portion is formed by an edge where the supply opening of the fuel gas flow path is located and an edge where the discharge opening of the oxygen-containing gas flow path is located in the plane direction of the three-layer plate. Since it is formed on the corner side portion, the portion is located on the corner side portion.

According to the characteristic configuration of the sixth aspect, the flow path forming member is provided so as to define the oxygen-containing gas flow path on the side of the electrolyte layer facing the oxygen electrode to form a cell of the fuel cell. I do. When a plurality of such cells are arranged side by side in the thickness direction in a state where they are spaced apart from each other, a fuel gas flow path separated from the oxygen-containing gas flow path is formed between the cells adjacent in the arrangement direction. can do. That is, a cell is formed by attaching one flow path forming member to one electrolyte layer, and a plurality of such cells are arranged side by side in the thickness direction at a distance from each other, and the An oxygen-containing gas flow path and a fuel gas flow path can be provided for each layer. Therefore, the structure for providing a plurality of electrolyte layers in the thickness direction with the oxygen-containing gas flow path and the fuel gas flow path provided for each of the electrolyte layers can be extremely simplified.

Further, between adjacent cells in the cell arrangement direction, a flexible conductive material formed so as to allow gas flow is filled so as to connect the cells on both sides in a conductive state. Therefore, even if the temperature rises with the operation of the fuel cell and each component constituting the fuel cell expands or warps, the flexibility of the flexible conductive material allows the cell and the flexible conductive material to be separated from each other. , The electrical connection between adjacent cells can always be maintained in a favorable state, and power loss can be suppressed.

With the above-described configuration, in a fuel cell in which the structure is simplified and the power loss is suppressed, when the present invention is implemented, an improvement in output can be achieved. It has become possible to provide a high fuel cell.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. A plurality of rectangular plate-shaped solid electrolyte layers 1 provided with an oxygen electrode 2 on one surface and a fuel electrode 3 on the other surface, and an oxygen-containing gas flow path s formed on the side facing the oxygen electrode 1; In a state where a conductive separator 4 as a flow path forming member having conductivity that partitions the fuel gas flow path f on the side facing the fuel electrode 3 is positioned between the adjacent electrolyte layers 1, The cell assembly NC is formed so as to be arranged in the thickness direction at an interval from each other. Supply opening si and discharge opening so of the oxygen-containing gas flow path s
Are provided separately at each of a pair of opposed edge portions of the solid electrolyte layer 1, and the supply opening f of the fuel gas flow path f is provided.
i and a discharge opening fo are separately provided at each of a pair of opposite edges of the solid electrolyte layer 1 so as to allow gas flow between the conductive separator 4 and the fuel electrode 3. Is filled with the flexible conductive material 5 formed in the above.

In the present invention, between the conductive separator 4 filled with the flexible conductive material 5 and the fuel electrode 3,
At a position spaced apart from the fuel electrode 3 in the direction in which the solid electrolyte layers 1 are arranged, the gas flow resistance is configured to be smaller than that of the flexible conductive material 5 so that the surface direction in the solid electrolyte layer 1 Is provided with a temperature difference suppressing passage P through which the fuel gas or the oxygen-containing gas flows to suppress the temperature difference.

First, referring to FIG. 1, the cell C of the fuel cell
Is added. A film-shaped or plate-shaped oxygen electrode 2 is formed on one surface of a rectangular plate-shaped solid electrolyte layer 1 in such a manner that a pair of opposed side edges of the solid electrolyte layer 1 each have an electrolyte layer exposed portion 1a extending over the entire side edge. Is attached integrally,
Further, a film-shaped or plate-shaped fuel electrode 3 is integrally attached to the other surface over the entire surface or almost the entire surface, and a rectangular three-layer plate Ce for obtaining an electromotive force from the oxygen electrode 2 and the fuel electrode 3 is provided. Is formed.

On the side of the three-layer plate Ce facing the oxygen electrode 2, a conductive separator 4 is provided so as to define an in-cell passage x functioning as an oxygen-containing gas passage s. The cell C of the fuel cell is formed. To further explain, the conductive separator 4 is formed of a plate-like portion 4a.
And a pair of band-shaped protrusions 4b located at both ends of the plate-shaped portion 4a and a plurality of ridges 4c positioned between the pair of band-shaped protrusions 4b. I have. A cell C is formed by attaching the pair of band-shaped protrusions 4b to each of the electrolyte layer exposed portions 1a in a state where the conductive separator 4 is in contact with the oxygen electrode 2 with each of the plurality of ridges 4c. It is. And oxygen electrode 2
And the conductive separator 4 are connected in a conductive state, and between the oxygen electrode 2 and the conductive separator 4, an oxygen-containing material is opened at one pair of opposite end surfaces of the cell C and closed at the other pair of opposite end surfaces. A gas flow path s is formed. Note that one of the pair of end openings of the oxygen-containing gas flow path s is connected to the oxygen-containing gas supply opening si.
The other is used as an opening for discharging the oxygen-containing gas so.

Therefore, in the oxygen-containing gas flow path s,
The oxygen-containing gas flows linearly from the supply opening si to the discharge opening so over the entire width of the flow path in the cell C in the direction along the opening edge. In the following description, in the cell C, the oxygen-containing gas flow path s
The edge where the end opening is located is referred to as an opening edge, and the end face where the oxygen-containing gas flow path s is closed is referred to as a closed end face.

The solid electrolyte layer 1 is made of tetragonal or cubic ZrO _{2 in} which about 3 to 10 mol% of Yt is dissolved, the oxygen electrode 2 is made of LaMnO ₃ , and the fuel electrode 3 is made of Ni.
And a cermet of ZrO ₂ . The conductive separator 4 is made of LaCrO ₃ having excellent oxidation resistance and reduction resistance.

Next, based on FIG. 2 to FIG.
Are arranged in the thickness direction at intervals so as to form an inter-cell flow path y functioning as a fuel gas flow path f between adjacent ones to form a cell set NC. Will be described. A plurality of cells C,
The cells are arranged in the thickness direction in a state where they are held at a distance from each other by a pair of space holding members 9 separately arranged at the pair of opening edges, respectively, and are arranged in the cell thickness direction (corresponding to the direction in which the electrolyte layers 1 are arranged). Each of the cells C adjacent to (1) is filled with a flexible conductive material 5 formed to allow gas flow. And by the flexible conductive material 5,
The cells C adjacent to each other in the cell arrangement direction are connected in a conductive state.

A fuel gas flow path f is formed between the cells C adjacent in the cell arrangement direction by partitioning both sides between the cells C adjacent in the cell arrangement direction with a pair of spacing members 9. The fuel gas flow path f is closed by a pair of spacing members 9 on both sides of the opening of the cell C, and is opened on both sides of both closed end faces of the cell C.
Note that one of the pair of end openings of the fuel gas flow path f is
The other is used as the fuel gas supply opening fi and the other is used as the fuel gas discharge opening fo.

Accordingly, the supply opening si and the discharge opening so of the oxygen-containing gas flow path s are formed in the solid electrolyte layer 1
The supply opening fi and the discharge opening fo of the fuel gas flow path f are separately provided at each of a pair of opposed edges, and each of the pair of opposed edges of the solid electrolyte layer 1 is provided at the other opposed pair of edges. It is provided separately.

The flexible conductive material 5 will be described.
As shown also in FIGS. 6 and 7, the temperature difference suppressing flow portion P provided in the flexible conductive material 5 transfers the fuel gas supplied from the supply opening fi to a position before the discharge opening fo and to the supply opening fi. A U-turn is made in front of each of the openings fi to allow a flow of 1.5 times back and forth between the supply opening fi and the discharge opening fo, and then discharge from the discharge opening fo. .

The temperature difference suppressing passage P is made of a flexible conductive material 5
Is provided with a gap portion V at a portion corresponding to an intermediate portion in the cell arrangement direction. The flexible conductive material 5 has a first conductive component 5A provided on one surface with a concave portion v forming a void portion V, and is configured so as to overlap the first conductive component 5A and close the concave portion v. The second conductive component 5B is divided into two in the cell arrangement direction. Then, the first conductive constituent members 5
A and the second conductive component 5B are overlapped with each other, and the concave portion v of the first conductive component 5A is closed by the second conductive component 5B to form the gap V.
That is, the concave portion v of the first conductive component 5A and the surface of the second conductive component 5B on the first conductive component 5A side function as a gap component.

The first conductive constituent member 5A is formed in a rectangular plate shape having substantially the same area as the cell C, and is formed by press-forming a Ni felt material so as to have a concave portion v on one surface thereof. I have. One end of the recess v has a fuel gas flow path f.
Open at the end face located at the supply opening fi, and extend linearly toward the discharge opening fo of the fuel gas flow path f, make a U-turn before the discharge opening fo, and further toward the supply opening fi. Meandering in front of the supply opening fi, and further linearly extending toward the discharge opening fo, and having the other end opening at the end face located at the discharge opening fo. It is formed in a shape. The five meandering concave portions v are arranged side by side in the direction along the closed edge of the cell C. The second conductive component 5B is formed by press-forming a Ni felt material into a rectangular plate having the same area as the first conductive component 5A.

The spacing member 9 will be described.
The spacing member 9 is formed in a plate shape having a length longer than the length of the opening edge of the cell C. By arranging each of the pair of spacing members 9 between the cells C along the opening edge of the cell C with both ends protruding from the closed end face of the cell C, It is configured so as to maintain the interval between.

Further, by connecting the frame forming member W to each of the spacing members 9, two passages connected in series in the cell arranging direction and communicating with the oxygen-containing gas flow paths s by respective end openings are formed. Form one. The passage facing the end opening used as the supply opening si is used as the supply oxygen side gas passage Si for supplying the oxygen-containing gas to each of the oxygen-containing gas flow paths s, and is used as the discharge opening so. The passage facing the end opening is used as a discharge oxygen side gas passage Se for discharging the oxygen-containing gas from each of the oxygen-containing gas passages s.

The frame forming member W will be further described. The frame forming member W includes a pair of first square rods 10 connected to projecting ends 9 a of the spacing member 9 projecting from the closed end surface of the cell C, and an end of each of the pair of first square rods 10. And a second rectangular rod-shaped body 11 connecting the two. The thickness of each of the first square rod 10 and the second square rod 11 in the cell arrangement direction is the same as the sum of the thickness of the cell C and the thickness of the spacing member 9. A recess 10a having the same depth as the thickness of the spacing member 9 is formed at one end of each of the first square rod-shaped members 10 to fit the protruding end 9a of the spacing member 9. Therefore, in the first square rod-shaped body 10, the thickness of the thin portion left by forming the concave portion 10a becomes the same as the thickness of the cell C. A concave portion 10b is formed at the other end of each of the first rectangular rod-shaped members 10, and a concave portion 11a for fitting the concave portion 10b of the first rectangular rod-shaped member 10 is formed at each of both ends of the second rectangular rod-shaped member 11. It is formed.

When connecting the first square rod 10 to the protruding end 9a of the spacing member 9, the side surface of the first square rod 10 is brought into close contact with the closed end face of the cell C. Thereby, the end opening of the oxygen-containing gas passage s and the end opening of the fuel gas passage f are partitioned in an airtight state.

Further, at one end of each of the spacing members 9,
A concave groove 9m is formed, and on each side of the first square rod-shaped body 10,
A groove 10m is formed so as to overlap with the groove 9m of the spacing member 9 when viewed in the cell arrangement direction, and the groove 9m and the groove 10m are connected in series in the cell arrangement direction, and will be described later. A pair of grooves M for fitting the side edges of the gas passage forming member 12 is formed.

Each of the spacing member 9, the first rectangular bar 10 and the second rectangular bar 11 is made of ceramic having electrical insulation and excellent heat resistance, oxidation resistance and reduction resistance.

Next, a configuration for extracting power from the cell assembly NC will be described with reference to FIGS. The current collector 1 provided with the flexible conductive material 5 in contact with each of the cells C at both ends in the cell array direction of the cell assembly NC, and further supported by the current collector support member 14.
5 is provided so as to be in contact with the flexible conductive material 5, and power is taken out by the current collector 15. In addition, similarly to the cell C, the current collecting unit supporting member 14 supporting the current collecting unit 15 is held on the cell assembly NC by the spacing member 9 and the frame forming member W.

Next, the overall structure of the fuel cell will be described with reference to FIGS. A pair of frame members 17 having the same frame shape as the frame formed by the spacing member 9 and the frame forming member W is placed on the base 16. Then, the cell assembly NC is placed on the pair of frame members 17 in a state where the opening of the frame formed by the spacing member 9 and the frame forming member W is aligned with the opening of the frame member 17. The frame member 17 also has
A concave groove 17m for forming the groove M is formed.

Then, a gas passage forming member 12 having a shape having three side surfaces and a top surface is provided in a state where the side edges on both sides thereof are fitted into the grooves M on both sides, respectively. A space communicating with each of the fuel gas flow paths f is defined by an end opening functioning as a supply opening fi, and the space is formed as a supply fuel side gas passage for supplying fuel gas to each of the fuel gas flow paths f. It is used as Fi. A spacing member 9 at the upper end of the cell assembly NC
A cover member 18 is provided so as to close the opening formed by the frame forming member W, and the supply oxygen-side gas passage Si
Further, the discharge oxygen side gas passage Se is closed.

Further, in a state where the cell assembly NC is installed,
The bottomed rectangular cylindrical body 19 is placed on the base 16. That is, the base 16 and the bottomed rectangular cylindrical body 19 form a box-shaped body B, and the cell assembly NC is provided inside the box-shaped body B. Of the pair of open ends of the fuel gas flow path f of each cell C, the open end that functions as the fuel gas discharge opening fo faces the inside of the box-shaped body B.
Then, a discharge fuel side gas passage F for discharging fuel gas from each of the fuel gas flow paths f through the internal space of the box-shaped body B is provided.
It is configured to be used as e.

An oxygen-containing gas supply pipe 20 is connected to the supply oxygen-side gas passage Si, and an oxygen-containing gas discharge pipe 21 is connected to the discharge oxygen-side gas passage Se via the base 16. A fuel gas supply pipe 22 is connected to the supply fuel gas passage Fi, and a fuel gas discharge pipe 23 is connected to the discharge fuel gas passage Fe via the base 16.
Oxygen-containing gas passage Si for supply from oxygen-containing gas supply pipe 20
Is supplied to each oxygen-containing gas flow path s from the supply opening si, flows through each oxygen-containing gas flow path s, and is discharged from each discharge opening so to the discharge oxygen-side gas passage S.
e and is discharged through the oxygen-containing gas discharge pipe 21.
On the other hand, from the fuel gas supply pipe 22 to the supply fuel side gas passage F
The fuel gas supplied to i flows into each fuel passage f from the supply opening fi, flows through each fuel passage f, flows out from each discharge opening fo to the discharge fuel side gas passage Fe, The fuel gas is discharged from the fuel gas discharge pipe 23.

The flow form of the oxygen-containing gas in the oxygen-containing gas flow path s and the flow form of the fuel gas in the fuel gas flow path f will be described below with reference to FIG.
FIG. 7A shows a state in which the cell C is partially cut out in the plane direction at an intermediate portion of the conductive separator 4 in the cell arrangement direction, and FIG. This shows a state in which the conductive material 5 is partially cut away in the plane direction at an intermediate portion of the first conductive constituent member 5A in the cell arrangement direction. In FIG. 7, the flow of the oxygen-containing gas is indicated by solid arrows, and the flow of the fuel gas is indicated by broken arrows.

As shown in FIG. 7A, the oxygen-containing gas flows through the oxygen-containing gas flow path s linearly from the supply opening si to the discharge opening so over the entire width of the flow path. Flow through. On the other hand, the fuel gas supplied from the supply opening fi reciprocates 1.5 times between the supply opening fi and the discharge opening fo by the guide of each meandering gap V in the flexible conductive material 5. After flowing in this state, it is discharged from the discharge opening fo. The fuel gas flowing through the gap V penetrates and diffuses into the flexible conductive material 5 and contacts the entire surface of the fuel electrode 2.

Since hydrogen in the fuel gas causes an electrode reaction during the flow of the fuel gas through the gap V, the content of hydrogen in the fuel gas flowing through the gap V is It becomes smaller in the order of the first outward section, the return section, and the last outward section. Therefore, in the fuel electrode 2, the supply opening f
In the direction perpendicular to the direction connecting i to the discharge opening fo, the first forward portion, the backward portion,
Since the fuel gas is supplied in cooperation with the final outward path, the electrode reaction occurs uniformly over the entire surface of the fuel electrode 2.

[Second Embodiment] Hereinafter, based on FIG.
A second embodiment of the present invention will be described. In the second embodiment, since the configuration other than the flexible conductive material 5 is the same as that of the above-described first embodiment, only the flexible conductive material 5 will be described below, and the other description will be omitted. Omitted.
The temperature difference suppressing flow portion P provided in the flexible conductive material 5 is:
As shown in FIG. 8 (b), the fuel gas is intensively introduced into a part of the fuel gas flow path f as viewed in the cell arrangement direction, passed through the part, and then passed through the other part. It is configured to flow.

That is, in the conventional fuel cell, FIG.
In the case where the temperature distribution as shown in FIG. 1 is generated, the highest temperature portion is located in the surface direction of the cell C, at the edge where the supply opening fi of the fuel gas flow path f is located, and at the position of the oxygen-containing gas flow path s. On the corner side formed by the edge where the supply opening si is located, it is formed in a portion having an area of about ４ of the whole. Therefore, the part is located in a part overlapping the highest temperature part in the cell arrangement direction, and in the part, a reforming reaction of the hydrocarbon gas is caused intensively, and the endothermic action causes the part to undergo the reforming reaction. Is configured to lower the temperature.

That is, as shown in FIG. 8B, the fuel gas is supplied from the supply opening fi of the fuel gas flow path f to the fuel gas flow from the supply opening si side of the oxygen-containing gas flow path s. After flowing into the flow path f, the fuel gas flows through the fuel gas flow path f through the following flow path, and is discharged from the discharge opening fo. First, in the plane direction of the cell C, an angle formed by an edge where the supply opening fi of the fuel gas flow path f is located and an edge where the supply opening si of the oxygen-containing gas flow path s is located. On the part side, about 1 for the whole
/ 4 area part (this part corresponds to the part)
Intensively, and let that part flow in a meandering shape,
In that portion, the reforming reaction of the hydrocarbon gas is caused intensively. Subsequently, the supply opening fi of the fuel gas flow path f
On the corner side formed by the edge portion where is located and the edge portion where the discharge opening so of the oxygen-containing gas flow path s is located, a portion having an area of about ４ of the whole is meandering. Through
Subsequently, the remaining half of the area is divided into an edge portion where the supply opening si of the oxygen-containing gas flow path s is located and the discharge opening s.
It is made to flow linearly toward the discharge opening fo over substantially the entire width between the edge where o is located.

The N in the cermet constituting the fuel electrode 3
i functions as a reforming catalyst for reforming the hydrocarbon-based gas in the fuel gas into a gas containing hydrogen gas.

As in the first embodiment, the temperature difference suppressing flow portion P is provided by providing a void V in a portion of the flexible conductive material 5 corresponding to an intermediate portion in the cell arrangement direction. It is like that. Further, the flexible conductive material 5
As in the first embodiment, a first conductive component 5A having a concave portion v that forms a gap V on one surface, and a first conductive component 5A that is superimposed on the first conductive component 5A so as to close the concave portion v. The second conductive constituent member 5B is divided into two in the cell arrangement direction. Then, the first conductive component 5A and the second conductive component 5b are overlapped with each other, and the concave portion v of the first conductive component 5A is closed by the second conductive component 5b, so that the gap V Is formed.

[Another Embodiment] Next, another embodiment will be described. (A) The shape of the flow path of the temperature difference suppressing flow portion P is not limited to the shape exemplified in each of the above embodiments, and the temperature difference in the surface direction in the electrolyte layer 1 may be suppressed. The shape can be variously changed. For example, as in the above embodiments, the oxygen-containing gas flow path s extends from the supply opening si to the discharge opening si over the entire width of the flow path width in the direction along the edge of the electrolyte layer 1. As shown in FIG. 9, a flexible conductive material 5 formed so as to flow straight or substantially straight toward so and filled between the conductive separator 4 and the fuel electrode 3 has a flow path shape as shown in FIG. 9. May be provided. That is, the fuel gas is caused to flow into the fuel gas flow path f from the portion of the supply opening fi of the fuel gas flow path f on the discharge opening so side side of the oxygen-containing gas flow path s, and the fuel gas flows in the plane direction of the cell C. In this case, the oxygen-containing gas flow path s is formed to flow through a portion corresponding to the discharge opening so side, and then to flow through a portion corresponding to the supply opening si side of the oxygen-containing gas flow path s. In this case, in the plane direction of the cell C, a portion through which the oxygen-containing gas having a small oxygen content flows flows through a fuel gas having a large hydrogen content and flows through an oxygen-containing gas having a large oxygen content. Since the fuel gas having a low hydrogen content flows through the portion where the gas flows, the temperature difference in the surface direction of the cell C can be reduced.

(B) In the first embodiment,
The temperature difference suppressing passage P has been described as an example in which the fuel gas is caused to flow in a state of reciprocating 1.5 times between the discharge opening fo and the supply opening fi. , 2.5 reciprocations or more. Also, the case where five temperature difference suppressing flow passages P are provided side by side in the direction along the closed edge of the cell C has been exemplified, but the number of temperature difference suppression flow passages P in this case can be changed. Yes, four or less or six or more.

(C) In the first embodiment,
In the temperature difference suppressing passage P, the oxygen-containing gas flow path s is arranged in a direction connecting the supply opening si and the discharge opening so,
The case where the cross-sectional area of each of the plurality of flow passage portions is the same has been described as an example. In this case, in the surface direction of the cell C, a portion corresponding to a portion through which the oxygen-containing gas having a small oxygen content flows has a large flow rate of the fuel gas flowing through the temperature difference suppressing flow portion P. The portion corresponding to the portion through which the oxygen-containing gas having a high oxygen content flows, while the degree of reduction in the hydrogen content in the fuel gas is small, is the fuel flowing through the temperature difference suppressing flow portion P. Since the gas flow rate is small, the degree of reduction in the hydrogen content in the fuel gas increases. Therefore, the temperature difference in the surface direction in the cell C can be further reduced.

(D) In each of the above embodiments, the case where the temperature difference suppressing flow portion P is provided in the middle of the flexible conductive material 5 in the cell arrangement direction has been described. Conductive separator 4 in conductive conductive material 5
May be provided on a surface portion that comes into contact with.

(E) In each of the above embodiments, the case where the temperature difference suppressing flow portion P is provided by providing the flexible conductive material 5 with the void V has been exemplified. It may be provided by providing the flexible conductive material 5 with a gas-permeable member having a smaller gas flow resistance. In this case, the air-permeable member may be a felt-like material of Ni similar to the flexible conductive material 5, but may be another member, and it does not matter whether or not the member has conductivity. Or N
A metal plate such as i is provided, and the metal plate is
A void portion functioning as the temperature difference suppressing flow passage portion P may be provided.

(F) The form of the flexible conductive material 5 for permitting gas flow can be variously changed. For example, it may be in the form of a sponge. The material forming the flexible conductive material 5 is also
Various changes are possible. For example, a felt-like material made of metal other than Ni and having excellent heat resistance and reduction resistance may be used. Alternatively, a ceramic felt-like material having excellent heat resistance and reduction resistance and having conductivity may be used.

(G) The flexible conductive material 5 is divided in the cell arranging direction so that each portion has a void portion constituting the void portion V, and the divided portions are overlapped to form the void portion. In the case of configuring to form V,
The flexible conductive material 5 may be divided in the cell arranging direction such that each portion has a gap component that forms the gap V. There are various forms other than the forms exemplified in the above embodiments. It is possible. For example, the first conductive component 5
A may be further divided into a plate-shaped portion and a slit forming portion provided with a slit for forming the gap portion V. In addition, the gap V is formed by dividing the two into two so as to provide a recess for forming the gap V in each of the two portions, and by overlapping the two divided portions, the openings of the respective recesses overlap. It may be in such a form.

(H) Cross-sectional shape of the flow path in the temperature difference suppressing flow passage portion P (cross-sectional shape in a plane perpendicular to the flow direction)
Is not limited to the rectangular shape illustrated in each of the above embodiments, and may be, for example, a circular shape or an oval shape.

(I) In each of the above embodiments, the case where the flexible conductive material 5 is filled only between the flow path forming member and the fuel electrode 3 has been described. Between them, the flexible conductive material 5 may be filled to provide the temperature difference suppressing flow portion P.

(G) In each of the above embodiments, the case where the flow path forming member 4 is provided to form the oxygen-containing gas flow path s on the side facing the oxygen electrode 2 in the electrolyte layer 1 has been described. A flow path forming member for forming a fuel gas flow path may be additionally provided on the side of the electrolyte layer 1 facing the fuel electrode 3 to form the fuel gas flow path f. In this case, the flexible conductive material 5 is filled between the fuel electrode 3 and the flow path forming member for forming the fuel gas flow path.

(L) In each of the above embodiments, the flow path forming member 4 is provided on the side of the electrolyte layer 1 facing the oxygen electrode 2 so as to define and form an oxygen-containing gas flow path s. Although the case of forming is exemplified, instead of this,
The flow path forming member 4 is provided on the side of the electrolyte layer 1 facing the fuel electrode 3 so as to define and define a fuel gas flow path f.
May be formed. In this case, a plurality of cells C are arranged side by side in the thickness direction at intervals so as to form an oxygen-containing gas flow path s between adjacent cells,
The flexible conductive material 5 is filled between adjacent cells C in the cell arrangement direction.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a cell of a fuel cell according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a configuration of a cell assembly of the fuel cell according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional plan view showing the entire configuration of the fuel cell according to the first embodiment of the present invention.

FIG. 4 is a view taken in the direction of the arrows in FIG. 3;

FIG. 5 is a view as viewed from the direction of the arrow in FIG. 3;

FIG. 6 is an exploded perspective view showing a configuration of a flexible conductive material according to the first embodiment of the present invention.

FIG. 7 is a diagram illustrating a flow form of an oxygen-containing gas and a fuel gas in the fuel cell according to the first embodiment of the present invention.

FIG. 8 is a view for explaining a flow form of an oxygen-containing gas and a fuel gas in a fuel cell according to a second embodiment of the present invention.

FIG. 9 is a plan view showing a configuration of a flexible conductive material in a fuel cell according to another embodiment.

FIG. 10 is a diagram showing a temperature distribution in a plane direction of a three-layer plate in a conventional fuel cell.

[Explanation of symbols]

 Reference Signs List 1 electrolyte layer 2 oxygen electrode 3 fuel electrode 4 flow path forming member 5 flexible conductive material 5A, 5B each part f fuel gas flow path fi supply opening fo discharge opening s oxygen-containing gas flow path si supply opening so discharge Opening C Cell P Temperature difference suppression flow passage V Void

Claims (6)

[Claims] 1. A plurality of rectangular plate-shaped electrolyte layers having an oxygen electrode on one surface and a fuel electrode on the other surface form an oxygen-containing gas flow path on a side facing the oxygen electrode, and A flow path forming member having conductivity that defines a fuel gas flow path on the side facing the fuel electrode is arranged in the thickness direction at an interval from each other while being positioned between adjacent electrolyte layers. The supply opening and the discharge opening of the oxygen-containing gas flow path are provided,
In the electrolyte layer, one opposed pair of edge portions is provided separately from each other, and a supply opening and a discharge opening of the fuel gas flow path are provided in the electrolyte layer in the other opposed pair of edge portions. Each of the flexible conductive members is separately provided, and is formed between the flow path forming member and the fuel electrode, or between the flow path forming member and the oxygen electrode, so as to allow gas to flow therethrough. A fuel cell filled with a material, wherein the flexible conductive material is filled, between the flow path forming member and the fuel electrode, or between the flow path forming member and the oxygen electrode, At a position spaced apart from the fuel electrode or the oxygen electrode in the direction in which the electrolyte layers are arranged, the gas flow resistance is configured to be smaller than that of the flexible conductive material, and the surface of the electrolyte layer Fuel gas or oxygen-containing gas to suppress the temperature difference in Fuel cell temperature difference suppression through flow section for flow is provided. 2. A structure in which the temperature difference suppressing flow portion is provided by providing a void portion in a portion of the flexible conductive material corresponding to an intermediate portion in a direction in which the electrolyte layers are arranged. The fuel cell according to claim 1, wherein: 3. The flexible conductive material is divided in the direction in which the electrolyte layers are arranged, and the divided parts are overlapped so that each part has a cavity part constituting the void part. 3. The fuel cell according to claim 2, wherein the gap is formed by the following. 4. The flow opening for suppressing a temperature difference causes a fuel gas or an oxygen-containing gas to make a U-turn in front of the discharge opening and in front of the supply opening, respectively. The fuel cell according to any one of claims 1 to 3, wherein the fuel cell is configured to flow in a state of reciprocating between the fuel cell and the opening. 5. A hydrocarbon-based gas in a fuel gas which is filled between the flow path forming member and the fuel electrode with the flexible conductive material, and is supplied to the fuel gas flow path from the supply opening. Is configured to be reformed into a gas containing hydrogen gas in the fuel gas flow path, wherein the temperature difference suppressing flow passage is configured to supply a fuel gas to the electrolyte layer in the fuel gas flow path. The fuel according to any one of claims 1 to 3, wherein the fuel is configured to flow intensively into a part as viewed in the arrangement direction, flow through the part, and then flow through the other part. battery. 6. The fuel cell according to claim 1, wherein the flow path forming member is provided on a side of the electrolyte layer facing the oxygen electrode so as to define the oxygen-containing gas flow path. A plurality of the cells are arranged side by side in a thickness direction at intervals to form the fuel gas flow path between adjacent ones, and the flexible conductive material is The fuel cell according to any one of claims 1 to 5, wherein a space is filled between cells adjacent in the arrangement direction.