JP4057822B2 - Fuel cell, cell stack and fuel cell - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel cell, a cell stack, and a fuel cell, and relates to a fuel cell, a cell stack, and a fuel cell that can improve power generation.
[0002]
[Prior art]
In recent years, various fuel cells in which a stack of fuel cells is accommodated in a storage container have been proposed as next-generation energy.
[0003]
FIG. 8 shows a cell stack of a conventional solid oxide fuel cell. This cell stack aggregates a plurality of fuel cells 1 (1a, 1b), and one fuel cell 1a and the other fuel cell. A current collecting member 5 made of metal felt is interposed between the cell 1b and the inner electrode 7 of one fuel cell 1a and the outer electrode 11 of the other fuel cell 1b are electrically connected in series. It had been.
[0004]
The fuel cell 1 (1a, 1b) is configured by sequentially providing a solid electrolyte 9 and an outer electrode 11 on the outer peripheral surface of a cylindrical inner electrode 7, and the inner electrode exposed from the solid electrolyte 9 and the outer electrode 11. 7 is provided with an interconnector 13 so as not to be connected to the outer electrode 11.
[0005]
This interconnector 13 is made of dense conductive ceramics that are not easily altered by the fuel gas and the oxygen-containing gas in order to reliably block the gas flowing inside the inner electrode 7 and the gas flowing outside the outer electrode 11. It is used.
[0006]
The electrical connection between one fuel cell 1a and the other fuel cell 1b will be specifically described. The inner electrode 7 of one fuel cell 1a is connected to an interconnector 13 provided on the inner electrode 7, a current collector. This is done by connecting to the outer electrode 11 of the other fuel cell 1b via the member 5.
[0007]
FIG. 9 shows a cell stack of a conventional solid electrolyte fuel cell of an interconnectorless type, and this cell stack is constituted by assembling a plurality of fuel cells 2 (2a, 2b). 2 includes a solid electrolyte 19 formed on the entire circumferential surface of the cylindrical inner electrode 17 and an outer electrode 21 w formed on the entire circumferential surface of the solid electrolyte 19.
[0008]
In each of the left and right fuel cell rows, a current collecting member 23 made of a metal felt or the like that connects the outer electrodes 21 is interposed between one fuel cell 2a and the other fuel cell 2b. The outer electrode 21 of the left fuel cell array and the inner electrode 17 of the right fuel cell array were electrically connected.
[0009]
FIG. 10 shows a cell stack of flat solid oxide fuel cells. This cell stack collects a plurality of fuel cells 3 (3a, 3b), one fuel cell 3a and the other. A current collecting member 25 made of metal felt or the like is interposed between the fuel cell 3b and the inner electrode 27 of one fuel cell 3a and the outer electrode 31 of the other fuel cell 3b are electrically connected. Was composed.
[0010]
The fuel cell 3 (3a, 3b) is configured by sequentially providing a solid electrolyte 29 and an outer electrode 31 on the outer peripheral surface of the flat inner electrode 27, and the inner electrode exposed from the solid electrolyte 29 and the outer electrode 31. 27 is provided with an interconnector 33 so as not to be connected to the outer electrode 31. A plurality of gas passage holes 32 are formed in the inner electrode 27.
[0011]
The electrical connection between one fuel battery cell 3a and the other fuel battery cell 3b is performed by connecting the inner electrode 27 of one fuel battery cell 3a via an interconnector 33 and a current collecting member 25 provided on the inner electrode 27. This is done by connecting to the outer electrode 31 of the other fuel cell 3b.
[0012]
[Problems to be solved by the invention]
However, the fuel cell shown in FIG. 8 has a drawback that about 20% of the entire circumference does not contribute to power generation because the portion where the interconnector 13 is formed does not generate power.
[0013]
In addition, the interconnector-less fuel cell shown in FIG. 9 has the advantage that the power generation region can be widened because the inner electrode, the solid electrolyte, and the outer electrode are formed all around the cell as compared with the cell shown in FIG. However, the effect is only improved by about 20% compared with the case of FIG. 6, and it does not lead to a dramatic increase in the amount of power generation per unit cell.
[0014]
Furthermore, in the flat fuel cell shown in FIG. 10, since the single cell can be made larger than the cell shown in FIG. 8, the power generation amount per single cell increases, but the portion where the interconnector is formed does not generate power. About 40% of the circumference did not contribute to power generation, and the advantage of this shape was not fully utilized.
[0015]
8 and 10 have interconnectors 13 and 33. The interconnectors 13 and 33 include a gas flowing inside the inner electrodes 7 and 27 and a gas flowing outside the outer electrodes 11 and 31, respectively. Is required, and the characteristics that it does not deteriorate with fuel gas and oxygen-containing gas are required, so it takes time to manufacture, and the possibility of gas leakage etc. cannot be thrown away, and the long-term reliability is low was there.
[0016]
In addition, in a solid oxide fuel cell (SOFC), it is necessary to heat the power generation cell to a high temperature of 600 to 1000 ° C. due to the characteristics of the solid electrolyte, and thus it is necessary to reduce the volume of the heated portion. The smaller the volume of the heated part, the smaller the energy consumed for heating the cell during startup or steady operation, so that startup can be quickened or power generation efficiency can be increased. For these reasons, particularly in a solid oxide fuel cell (SOFC), not only the power generation amount of a single cell but also the reduction of the stack volume per predetermined power generation amount is an important factor.
[0017]
That is, in the case of using a cylindrical type interconnector-less cell in FIG. 9, although there is a slight improvement, a large amount of cells are required to generate a predetermined amount of power, and the stack volume is increased accordingly. Since many cells are required, the reliability tends to decrease.
[0018]
In the flat fuel cell shown in FIG. 10, the power generation amount per cell can be increased by increasing the size (increasing the width). However, the interconnector 33 is formed so that about 40% of the entire circumference does not generate power. Therefore, a large number of cells are required to generate a predetermined amount of power, and the stack volume becomes large, and the connection reliability tends to decrease correspondingly.
[0019]
The present invention provides a fuel cell, a cell stack, and a fuel cell that can improve the power generation amount per unit cell, can be easily manufactured, can improve reliability, and can reduce the stack volume per predetermined power generation amount. With the goal.
[0020]
[Means for Solving the Problems]
The fuel battery cell of the present invention is Gas passage hole was formed in the axial direction An outer surface of an inner electrode is provided with an annular solid electrolyte so as to surround the inner electrode, and an outer surface of the solid electrolyte is provided with an annular outer electrode so as to surround the solid electrolyte. A pair of flat portions formed in parallel, and the flat portions In a direction perpendicular to the axial direction It is made into the flat shape comprised from the arc-shaped part which connects edge parts, and ratio R2 / R1 of the minor axis R1 which is the distance between the said flat parts, and the major axis R2 which is the distance between the said arc-shaped parts is 8 or more. The minor axis R1 is 8 mm or less.
[0021]
In such a fuel cell, since the annular solid electrolyte and the outer electrode are sequentially formed on the outer peripheral surface of the inner electrode, and the interconnector is not formed, it is easy to manufacture, and the entire periphery of the cell is the power generation unit. It is possible to effectively generate power by using the entire circumference of the cell, and the power generation amount per fuel cell increases, and as a result, the number of cells required per predetermined power generation amount can be reduced. In addition, as the number of cells decreases, the total number of connections between cells decreases, and the total number of connections that can cause a failure can be reduced, improving reliability.
[0022]
Further, by forming the solid electrolyte and the outer electrode on the flat inner electrode and forming the flat cell, the cell can be enlarged (widened) and the power generation amount per fuel cell can be increased. However, even if the size of the cell is increased in this way, the stack volume required to generate a predetermined amount of electricity can be made smaller than before, which can make the fuel cell more compact and reduce the required volume of the heated part. It is possible to minimize the energy used for cell heating during start-up or steady operation, thereby enabling quick start-up and improving power generation efficiency.
[0023]
Further, the fuel cell of the present invention has a flat shape composed of a pair of flat portions formed substantially in parallel and an arc-shaped portion connecting the ends of the flat portions. It is said .
[0024]
In the fuel cell having such a configuration, the stack volume necessary for generating a predetermined amount of power can be minimized, the stress generated in the solid electrolyte and the external electrode in the arc-shaped portion can be suppressed, and peeling and cracking can be prevented. Can be suppressed.
[0025]
That is, the fuel cell is arranged in the storage container so that the flat portions of the adjacent cells are opposed to each other. For example, when connecting the flat portions (parallel connection), the cells are connected via the conductive member. Can be connected to the entire flat part, so that the connection reliability can be improved and the distance between the cells can be reduced because the reliability is improved. On the other hand, when connecting in series, the flat parts are not connected to each other. Although it is necessary to arrange them at a predetermined interval, since the facing surfaces of the cells are flat, the distance between the cells can be reduced and the stack volume can be reduced.
[0026]
The fuel cell of the present invention so The ratio R2 / R1 of the minor axis R1 to the major axis R2 is 2 or more It is said that. Thereby, since the power generation amount per cell can be increased, the number of cells required for generating a predetermined amount of power can be reduced, and the number of connections between cells can be reduced.
[0027]
Also, minor axis R1 Is 8 mm or less It is said . Thereby, the stack volume required for generating a predetermined amount of power can be further reduced.
[0029]
In the fuel cell of the present invention, it is desirable that a conductive member that is electrically connected to the inner electrode is provided in the gas passage hole of the inner electrode. On the outer surface of the fuel cell, there is an interconnector-less type that does not form an interconnector that connects the cells, but by electrically connecting the conductive member to the inner electrode, current is passed from the inner electrode through the conductive member. It can be taken out.
[0030]
Further, a long conductive member is inserted into the gas passage hole of the inner electrode, and the long conductive member and the inner electrode are electrically connected between the long conductive member and the inner surface of the inner electrode. It is desirable that a conductive member for connection to be provided is provided. Thereby, an electric current can be taken out from an elongate conductive member through the connection conductive member which conducts with the inner electrode.
[0031]
The cell stack of the present invention is formed by aggregating a plurality of the fuel cells. In such a cell stack, since the power generation amount per cell can be increased, the number of cells required for generating a predetermined amount of power can be reduced, and the cell shape is flat, so that a predetermined power generation amount can be obtained. The stack volume can be reduced.
[0032]
Further, the fuel cell of the present invention comprises a plurality of the above fuel cell units stored in a storage container. Such a fuel cell can be miniaturized, and can reduce manufacturing costs, improve power generation efficiency, mountability, mount reliability, and maintainability.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a fuel cell of the present invention, where (a) is a cross-sectional view and (b) is a perspective view. The fuel battery cell 34 of the present invention is flat with an interconnector-less shape, and a dense solid is formed on the entire outer peripheral surface of a fuel-side electrode (inner electrode) 35 mainly composed of a flat and porous metal. An electrolyte 37 is formed, and an oxygen side electrode (outer electrode) 39 made of porous conductive ceramics is sequentially laminated on the entire outer peripheral surface of the solid electrolyte 37. The fuel side electrode 35 serves as a support. ing.
[0034]
That is, in the fuel cell 34, an annular solid electrolyte 37 is provided on the outer surface of the flat fuel-side electrode 35 so as to surround the fuel-side electrode 35, and the solid electrolyte 37 is surrounded on the outer surface of the solid electrolyte 37. Is provided with an annular oxygen-side electrode 39. One fuel gas passage hole 41 is formed in the fuel side electrode 35 in the axial direction. In the case of manufacturing a fuel cell, the cell is supported and fixed. However, the oxygen side electrode 39 does not have to be formed for the portion to be supported and fixed.
[0035]
The fuel-side electrode 35 includes a pair of flat portions 35a provided so as to face each other substantially in parallel, and arc-shaped portions 35b provided at both ends in the width direction and smoothly connecting the ends of the pair of flat portions 35a. These arc-shaped portions 35b are formed in an arc shape protruding outward. In the fuel side electrode 35, one gas passage hole 41 having a cross-sectional shape similar to the outer shape is formed.
[0036]
The fuel battery cell 34 is formed with a pair of flat portions 34a whose outer shapes are formed substantially in parallel according to the shape of the fuel-side electrode 35, and both ends of the flat portions 34a, and the pair of flat portions 34a. It is comprised from the arc-shaped part 34b which connects the edge parts.
[0037]
2A and 2B show another fuel battery cell 43 of the present invention, in which FIG. 2A is a transverse sectional view and FIG. 2B is a perspective view. The fuel cell 43 has the same structure as that shown in FIG. 1 except that a plurality of fuel gas passage holes 45 are formed in the fuel side electrode 44 in the axial direction. Reference numeral 46 denotes a solid electrolyte, 47 denotes an oxygen side electrode, 43a denotes a flat portion of the fuel cell 43, 43b denotes an arcuate portion of the fuel cell 43, 44a denotes a flat portion of the fuel side electrode 44, and 44b denotes a fuel side electrode 44. The arc-shaped part is shown.
[0038]
FIG. 3 shows still another fuel battery cell 49 of the present invention. In this fuel battery cell 49, an annular solid electrolyte 53, an oxygen side electrode are formed on a part of the outer peripheral surface of the fuel side electrode 51 in the axial length direction. Except that 55 is formed, it has the same structure as FIG. Accordingly, the fuel side electrode 51 protrudes from one end of the fuel cell 49. Reference numeral 57 denotes a fuel gas passage hole, 49a denotes a flat portion of the fuel battery cell 49, and 49b denotes an arcuate portion of the fuel battery cell 49.
[0039]
The fuel side electrodes 35, 44, 51 are mainly composed of any one of metals, metal oxides, or alloys or alloy oxides of Ni, Co, Ti, and Ru. In addition to these, In order to improve the bonding strength of the outer surface to the solid electrolytes 37, 46, and 55 and approximate the thermal expansion coefficient of the solid electrolytes 37, 46, and 55, it is desirable to contain a solid electrolyte material. As the metal or metal oxide, Ni or NiO is desirable from the viewpoint of cost. When the fuel side electrode is formed of a metal oxide, power is generated by reduction in a reducing atmosphere.
[0040]
The ratio R2 / R1 between the minor axis R1 and the major axis R2 of the fuel cell shown in FIGS. 8 more than It is said . Thereby, the number of cells required to generate a predetermined amount of power can be reduced.
[0041]
In addition, as described above, the fuel cells 34, 43, and 49 include a pair of flat portions 34a, 43a, and 49a, and arc-shaped portions 34b, 43b that smoothly connect both ends of the flat portions 34a, 43a, and 49a, 49b, the distance between the pair of flat portions 34a, 43a, 49a is the short diameter R1, and the maximum distance is the length in the direction perpendicular to the short diameter R1. It was.
[0042]
The short diameter R1 of the fuel cell is 8 mm or less It is said . Thereby, the volume of a fuel cell can be made small and the output density per volume can be improved. In particular , 6 mm or less is desirable.
[0043]
The solid electrolytes 37, 46, 55 provided on the outer surfaces of the fuel side electrodes 35, 44, 51 are partially stabilized or stabilized ZrO containing 3 to 15 mol% Y and rare earth elements. ₂ Dense ceramics are used. Between the fuel side electrodes 35, 44, 51 and the solid electrolytes 37, 46, 55, a bonding layer made of a dense layer may be interposed in order to improve the bonding strength. The thickness of the solid electrolytes 37, 46, and 55 is preferably 10 to 100 μm from the viewpoint of preventing gas permeation.
[0044]
The oxygen side electrodes 39, 47 and 55 are made of LaMnO. _Three Material, LaFeO _Three Material, LaCoO _Three It is comprised from the at least 1 type of porous electroconductive ceramics of a system material. The oxygen side electrodes 39, 47, and 55 have LaFeO in view of their high electrical conductivity at a relatively low temperature of about 600 to 1000 ° C. _Three System materials are desirable. The thickness of the oxygen side electrodes 39, 47, and 55 is preferably 30 to 100 μm from the viewpoint of current collection.
[0045]
A method for manufacturing the fuel cell as described above will be described. First, for example, NiO powder and ZrO containing Y ₂ (YSZ) A fuel-side electrode material obtained by mixing a powder, an organic binder, and a solvent is extruded to produce a flat fuel-side electrode molded body in which fuel gas passage holes are formed in the axial length direction. To dry.
[0046]
Next, for example, a sheet-like molded body is prepared using a solid electrolyte material in which YSZ powder, an organic binder, and a solvent are mixed, and this sheet-shaped molded body is formed on the fuel-side electrode molded body at both ends thereof. Wrap and dry so that there is no overlap between them.
[0047]
Next, the laminated molded body is treated to remove the binder, and co-fired at 1300 to 1600 ° C. in an oxygen-containing atmosphere. _Three The fuel cell of the present invention can be manufactured by dipping in a paste containing a system material and a solvent, forming an oxygen-side electrode molded body on the surface of the solid electrolyte by dipping, and baking at 1000 to 1300 ° C.
[0048]
Alternatively, a solid electrolyte sheet-like molded body may be formed on the surface of the fuel-side electrode molded body, and an oxygen-side electrode molded body may be further formed, and then fired simultaneously. Further, the fuel-side electrode molded body is dipped in the slurry containing the solid electrolyte material and dried, and further, dipped in the slurry containing the oxygen-side electrode material, dried, and co-fired. good.
[0049]
In the fuel cell configured as described above, annular solid electrolytes 37, 46, and 55 are provided on the outer surfaces of the flat fuel-side electrodes 35, 41, and 47 so as to surround the fuel-side electrodes 35, 44, and 51, respectively. An annular oxygen side electrode 39, 47, 55 is provided on the outer surface of the solid electrolyte 37, 46, 55 so as to surround the solid electrolyte 37, 46, 55, and the outer peripheral surface of the fuel side electrode 35, 44, 51 is provided. Since the annular solid electrolytes 37, 46, 55 and the oxygen side electrodes 39, 47, 55 are formed and the interconnector is not formed, the manufacturing is easy, and the entire circumference of the cell can be used as a power generation unit. It is possible to generate power by effectively using the entire circumference of the cell, and the power generation amount per fuel cell increases, and as a result, the number of cells required to obtain a predetermined amount of power generation can be reduced.
[0050]
Further, as the number of cells decreases, the total number of connections between cells decreases, and the number of connections that can cause a failure can be reduced, so that the mounting reliability can be improved.
[0051]
Furthermore, in order to generate a predetermined amount of power by forming solid electrolytes 37, 46, 55 and oxygen side electrodes 39, 47, 55 on the flat fuel side electrodes 35, 44, 51, and forming flat cells. The required stack volume can be made smaller than before, the required heated part volume can be reduced, and the energy required for heating the cell during start-up or steady operation can be reduced.
[0052]
FIG. 4 shows a cell stack of the present invention formed using the fuel battery cell of FIG. As shown in FIG. 4, the cell stack is constituted by a plurality of the fuel cells shown in FIG. As shown in FIG. 4 and FIG. 5 (b), the fuel cell 34 of this cell stack has an inner long conductive member 61 inserted in the center in the fuel gas passage hole 41 of the fuel side electrode 35. Between the long conductive member 61 and the inner surface of the fuel side electrode 35, a connecting conductive member 63 that connects the inner long conductive member 61 and the fuel side electrode 35 is provided.
[0053]
The inner elongate conductive member 61 has a conductive rod shape or plate shape, and the connection conductive member 63 is made of Ni felt so that fuel gas can pass therethrough. The inner long conductive member 61 and the connection conductive member 63 are not necessarily formed of Ni.
[0054]
Further, on the outer surface of the oxygen side electrode 39 corresponding to the flat portion 34a of the fuel battery cell 34,
An outer long conductive member 65 is provided and is electrically connected. The outer long conductive member 65 may be formed on a part of the oxygen side electrode 39 or on the entire surface.
[0055]
Adjacent fuel cells 34 are connected to each other by connecting the inner elongated conductive member 61 of one fuel cell 34 and the outer elongated conductive member 65 of the other fuel cell 34. They are electrically connected in series.
[0056]
The outer long conductive member 65 is preferably made of at least one of Pt, Ag, Ni-base alloy, and Fe—Cr steel alloy from the viewpoint of heat resistance, oxidation resistance, and electrical conductivity during power generation. .
[0057]
As shown in FIG. 5A, a connecting conductive member 63 made of Ni felt may be provided in the fuel gas passage hole 41 of the fuel side electrode 35 without inserting the inner long conductive member. Although good, from the viewpoint of current collection, it is desirable to insert the inner long conductive member 61 as shown in FIG.
[0058]
Further, as shown in FIG. 5C, both ends of the inner long conductive member 61 can be projected outward from both ends of the fuel cell 34. In this case, current can be extracted from both sides of the cell.
[0059]
The fuel cell 43 shown in FIG. 2 can also employ a cell stack structure as shown in FIGS. In this case, the inner long conductive member may be inserted into all of the plurality of fuel gas passage holes 45 or may be inserted into some of the fuel gas passage holes 45. Further, in the fuel battery cell 49 shown in FIG. 3, since one of the fuel side electrodes 51 is exposed, in addition to the cell stack structure as shown in FIG. 4 and FIG. Electric power can be taken out using the fuel-side electrode 51 without using a conductive member.
[0060]
The fuel cell of the present invention is configured by accommodating the cell stack described above in a storage container. That is, the storage container is provided with a supply pipe for introducing oxygen-containing gas (air) into the cell stack and a supply pipe for introducing fuel gas, and the oxygen-containing gas flows along the oxygen-side electrode of the fuel cell. At the same time, the fuel cell flows along the fuel side electrode and is heated to, for example, about 1000 ° C., so that the fuel cell starts to generate power.
[0061]
In addition, this invention is not limited to the said form, A various change is possible in the range which does not change the summary of invention. For example, the oxygen side electrode may be used as the inner electrode.
[0062]
【Example】
First, NiO powder having an average particle diameter of 0.5 μm and ZrO having an average particle diameter of 0.5 μm containing 8 mol% of Y ₂ A fuel-side electrode material in which (YSZ) powder, a pore agent, an organic binder made of PVA, and a solvent made of water were mixed was extruded to produce a flat fuel-side electrode molded body, which was dried.
[0063]
Next, a sheet-like molded body is produced using a solid electrolyte material in which the YSZ powder, an organic binder made of an acrylic resin, and a solvent made of toluene are mixed, and this sheet-like molded body is made into a fuel-side electrode molded body. It was wound on the upper side so as not to be separated from each other and dried, and a laminated molded body in which a solid electrolyte sheet-like molded body was laminated on the fuel-side electrode molded body was produced.
[0064]
Next, the laminated molded body was debindered and co-fired at 1500 ° C. in the air. This laminate is made of La having an average particle diameter of 2 μm. _0.6 Sr _0.4 Co _0.2 Fe _0.8 O _Three It is immersed in a paste containing a powder and a solvent composed of normal paraffin, and an oxygen-side electrode molded body is prepared by dipping on the surface of the solid electrolyte and baked at 1150 ° C. to form an oxygen-side electrode, as shown in FIG. The fuel battery cell of the present invention was produced.
[0065]
In addition, by changing the minor axis and major axis of the fuel side electrode, the minor axis R1 and the major axis R2 of the fuel cell were changed, and fuel cells having different R2 / R1 ratios were produced.
[0066]
Next, an outer long conductive member made of Pt-based metal having oxidation resistance is connected to the oxygen side electrode, and an inner long conductive member is formed at the center of the fuel gas passage hole in the fuel side electrode of the prepared cell. Was inserted, and the inner elongated conductive member and the fuel side electrode were connected by a connecting conductive member made of Ni felt to produce a cell as shown in FIG.
[0067]
The produced fuel cell was heated to 900 ° C., hydrogen gas was circulated through the fuel gas passage hole in the fuel side electrode, air was circulated outside the fuel cell, and the amount of power generation per cell was measured. . Based on this measurement result, the number of cells required to obtain a power generation amount of 1.5 KW and the volume of the cell stack constituted by the required number of cells were determined. At this time, in order to prevent an electrical short circuit or from the viewpoint of production, the calculation was performed with a setting that a space of 6 mm was required on the outer periphery of the cell. These results are shown in FIG.
[0068]
FIG. 6 shows the relationship between the minor axis R1, the ratio R2 / R1 and the volume of the cell stack. The number of cells necessary for obtaining a power generation amount of 1.5 kW in a cylindrical cell having a diameter of 4 mm is shown. The stack volume when used was 100,000. In FIG. 6, the point of R2 / R1 = 1 indicates the result of the cylindrical cell.
[0069]
From the results of FIG. 6, when the minor axis R1 is 20 mm, the volume tends to increase as the R2 / R1 ratio increases, and there is no effect of reducing the volume of the heated portion of the cell stack, and the thermal efficiency rather decreases. It turns out that there is a tendency. It can be seen that when R1 is 10 mm, the volume decreases slightly as the R2 / R1 ratio increases.
[0070]
Furthermore, when R1 is 8 mm or less, it is clear that the volume decreases as the R2 / R1 ratio increases. It can be seen that a cell having an R1 of 4 mm can reduce the volume by about 35% compared to the cylindrical shape when the R2 / R1 ratio is 8. Therefore, it can be seen from this result that the stack volume can be reduced by setting R1 to 10 mm or less and the R2 / R1 ratio to 2 or more.
[0071]
FIG. 7 shows the relationship between the minor axis R1, the R2 / R1 ratio, and the number of cells. According to FIG. 7, it can be seen that the larger the R1, the smaller the number of cells. However, when R1 is 20 mm, there is no effect of reducing the volume from the result of FIG.
[0072]
For cells with R1 of 10 mm or less, the number of cells tends to decrease as the ratio of R1, R2 / R1 increases, but when R1 is 4 mm, the number of cells is R2 / R when the R2 / R1 ratio is 8. It can be seen that R1 is 1/5 or less compared to 1 and the number of cells can be greatly reduced. Accordingly, from the results shown in FIGS. 6 and 7, R1 is set to 10 mm or less and R2 / R1 ratio is set to 2 or more, that is, the cell shape is flattened to reduce the volume of the heated portion and further reduce the number of cells. You can achieve that at the same time. For example, in the case of a cell with R1 of 4 mm, if the R2 / R1 ratio is 8, the volume can be made 70% compared to the case of using a cell with an R2 / R1 ratio of 1, and the number of cells Can also be reduced to 1/5 or less.
[0073]
【The invention's effect】
In the fuel battery cell of the present invention, the cell shape is flat and adopts an interconnector-less type, which is easy to manufacture and can improve the power generation amount as a single cell, and the number of cells relative to the desired power generation amount. In addition, it is possible to simultaneously reduce the volume that requires heating, including the cell power generation unit and its peripheral members, and it is possible to reduce manufacturing costs, improve power generation efficiency, mountability, mounting reliability, and maintainability. .
[Brief description of the drawings]
FIG. 1 shows a fuel cell of the present invention having one gas passage hole, wherein (a) is a cross-sectional view and (b) is a perspective view.
FIGS. 2A and 2B show a fuel battery cell of the present invention in which a plurality of gas passage holes are formed, wherein FIG. 2A is a cross-sectional view and FIG. 2B is a perspective view.
FIG. 3 is a perspective view showing a fuel battery cell of the present invention in which a plurality of gas passage holes are formed and an inner electrode protrudes.
FIG. 4 is a cross-sectional view showing a cell stack of the present invention.
FIG. 5A is a longitudinal sectional view of a fuel cell in which a connecting conductive member is inserted into a gas passage hole, and FIG. 5B is an inner long conductive member and a connecting conductive member disposed in the gas passage hole. FIG. 4C is a longitudinal sectional view of the fuel battery cell in which the inner long conductive member is protruded on both sides.
FIG. 6 is a graph showing the relationship between the ratio (R2 / R1) between the minor axis R1 and the major axis R2 of the fuel cell and the volume.
FIG. 7 is a graph showing the relationship between the ratio (R2 / R1) between the short diameter R1 and the long diameter R2 of the fuel cell and the number of cells.
FIG. 8 is a cross-sectional view showing a conventional cell stack in which a plurality of cylindrical fuel cells having interconnectors formed therein are connected.
FIG. 9 is a cross-sectional view showing a conventional cell stack in which a plurality of interconnectorless fuel cells are connected in parallel.
FIG. 10 is a cross-sectional view showing a conventional cell stack in which a plurality of flat fuel cells having interconnectors formed therein are connected in series.
[Explanation of symbols]
34, 43, 49 ... Fuel cells
34a, 43a, 49a ... flat part of the cell
34b, 43b, 49b ... Arc portion of the cell
35, 44, 51 ... Fuel side electrode (inner electrode)
37, 46, 53 ... Solid electrolyte
39, 47, 55 ... Oxygen side electrode (outer electrode)
41, 45, 57 ... Gas passage holes
61 ... Inner long conductive member
63... Conductive member for connection
R1 ... minor axis
R2 ... major axis

Claims (5)

An annular solid electrolyte is provided on the outer surface of the inner electrode having a gas passage hole formed in the axial direction so as to surround the inner electrode, and an annular outer electrode is provided on the outer surface of the solid electrolyte so as to surround the solid electrolyte. The outer shape of the fuel cell is a pair of flat portions formed in parallel and an arcuate portion that connects ends of the flat portions in a direction perpendicular to the axial length direction. The ratio R2 / R1 of the minor axis R1 which is the distance between the flat parts and the major axis R2 which is the distance between the arcuate parts is 8 or more, and the minor axis R1 is 8 mm or less. A fuel cell. Wherein the the gas passage holes of the inner electrode, the fuel cell according to claim 1, characterized in that the conductive member electrically connected to the inner electrode is provided. An elongated conductive member is inserted into the gas passage hole of the inner electrode, and the elongated conductive member and the inner electrode are electrically connected between the elongated conductive member and the inner electrode inner surface. fuel cell according to claim 1, wherein the connecting conductive member is provided. A cell stack comprising a plurality of fuel battery cells according to any one of claims 1 to 3 . Fuel cell, characterized in that comprising a plurality accommodated in the accommodation container the fuel cell according to any one of claims 1 to 3.

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