fuel cells

Abstract

To provide a fuel cell that can increase power generation while suppressing cracking. [Solution] The fuel cell comprises a metal support, a first electrode provided on the metal support and mainly composed of ceramics, an oxide-type solid electrolyte layer provided on the first electrode, and a second electrode provided on the solid electrolyte layer, having a different polarity from the first electrode and mainly composed of ceramics, wherein the metal support, the first electrode, and the solid electrolyte layer have a hexagonal shape of substantially the same size in plan view.

Description

Technical Field

[0001] The present invention relates to a fuel cell.

Background Art

[0002] With the evolution of digital devices and the advancement of wireless communication, the utilization of IoT (Internet of Things) is expected in various industries. In particular, small IoT sensors will use the measured data for cooperation, storage, analysis, and operation control of devices. In addition, advanced calculation methods such as AI (Artificial Intelligence) are incorporated into the analysis inside the edge device, and it is considered that the power consumption inside the device will increase. To operate these devices, a small power supply device is required, and one proposal is the use of a palm-sized solid oxide fuel cell.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When trying to miniaturize a solid oxide fuel cell, there is a risk that the area of the region contributing to power generation becomes small and sufficient power generation cannot be obtained, or there is a risk that the reaction gas does not flow properly and the pressure loss increases. Therefore, it is conceivable to devise the shape of the cell through which the reaction gas flows properly to increase the area of the region contributing to power generation. However, in this case, depending on the shape of the cell, there is a risk that sufficient power generation cannot be obtained. In addition, there is a risk that cracks will occur in the ceramic part during temperature rise.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a fuel cell capable of increasing the power generation amount while suppressing cracks. [Means for solving the problem]

[0006] The fuel cell according to the present invention comprises a metal support, a first electrode provided on the metal support and mainly composed of ceramics, an oxide-type solid electrolyte layer provided on the first electrode, and a second electrode provided on the solid electrolyte layer, having a different polarity from the first electrode and mainly composed of ceramics, wherein the metal support, the first electrode, and the solid electrolyte layer have a hexagonal shape of substantially the same size in plan view.

[0007] In the above fuel cell, the metal support is 0.16 (W / m·℃) × 10 2 Above, 0.27(W / m・℃)×10 2 It may have the following thermal conductivity.

[0008] The fuel cell may include an interconnector provided on the main surface of the metal support opposite to the first electrode, and a reaction gas flow path may be provided on the main surface of the interconnector on the metal support side.

[0009] In the fuel cell described above, the reaction gas flow path includes a power generation gas flow path for supplying reaction gas to the first electrode, the power generation gas flow path has a hexagonal shape that is approximately the same size as the metal support, and the reaction gas flow path may include an introduction flow path leading to the first corner of the hexagonal shape of the power generation gas flow path, and an exhaust flow path for discharging the reaction gas from the second corner facing the first corner of the hexagonal shape.

[0010] In the fuel cell described above, the interconnector may have a hexagonal shape in plan view that is approximately the same size as the metal support.

[0011] In the fuel cell described above, the reaction gas flow path comprises a power generation gas flow path for supplying reaction gas to the first electrode in the center of the interconnector, and an introduction flow path formed around the power generation gas flow path for introducing the reaction gas into the power generation gas flow path, wherein the power generation gas flow path has a hexagonal shape in a plan view with respect to the interconnector, the introduction flow path connects to the first corner of the hexagonal shape of the power generation gas flow path, and the reaction gas flow path may also include an discharge flow path for discharging the reaction gas from a second corner of the hexagonal shape of the power generation gas flow path that is opposite to the first corner. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a fuel cell that can increase power generation while suppressing cracking. [Brief explanation of the drawing]

[0013] [Figure 1] (a) is a top view of a solid oxide fuel cell according to the first embodiment, and (b) is a cross-sectional view of (a) along line AA. [Figure 2] (a) is a perspective view of the interconnector, (b) is an example of an intermediate member to be placed on top of the interconnector, and (c) is a perspective view of the cover member. [Figure 3] This is a cross-sectional view of a fuel cell. [Figure 4] This diagram illustrates a fuel cell with a circular shape. [Figure 5] This is a plan view of the interconnect. [Figure 6] (a) and (b) are diagrams illustrating positioning. [Figure 7] (a) to (c) are diagrams illustrating positioning. [Figure 8] This diagram illustrates the application of a sealing material. [Figure 9] (a) is a cross-sectional view of a fuel cell, and (b) is a diagram illustrating a cover member. [Modes for carrying out the invention]

[0014] Hereinafter, embodiments will be described while referring to the drawings.

[0015] (First Embodiment) FIG. 1(a) is a top view of a solid oxide fuel cell unit 100 according to the first embodiment. FIG. 1(b) is a cross-sectional view taken along line A-A of FIG. 1(a). As illustrated in FIG. 1(a), the fuel cell unit 100 has a hexagonal shape in plan view. The hexagonal shape formed by the fuel cell unit 100 does not have to be a regular hexagon. As an example, the fuel cell unit 100 has a regular hexagonal shape in plan view. For example, when the fuel cell unit 100 has a regular hexagonal shape, differences may occur in the lengths of each side due to manufacturing errors or the like. Also, differences may occur in the angles of each corner of the regular hexagonal shape due to manufacturing errors or the like. Also, each corner of the hexagonal shape may be rounded.

[0016] As illustrated in FIG. 1(b), as an example, the fuel cell unit 100 has a structure in which an anode 20 mainly composed of ceramics, an electrolyte layer 30, a cathode 40 mainly composed of ceramics, and a current collector 50 are laminated in this order on the first main surface of the metal support 10 out of the first main surface and the second main surface of the metal support 10. In the fuel cell unit 100, as long as a first electrode, an oxide-type solid electrolyte layer, and a second electrode having a polarity different from that of the first electrode are laminated on the metal support 10, an example in which the first electrode is the anode 20 and the second electrode is the cathode 40 will be described.

[0017] Each of the metal support 10, anode 20, electrolyte layer 30, cathode 40, and current collector 50 has a hexagonal shape in plan view. The metal support 10, anode 20, and electrolyte layer 30 have hexagonal shapes of substantially the same size in plan view. The cathode 40 and current collector 50 may have a hexagonal shape of substantially the same size as the metal support 10 in plan view, but may have a hexagonal shape smaller than the metal support 10 and have a center of gravity at the same position as the center of gravity of the metal support 10. In the present embodiment, as an example, as illustrated in FIGS. 1(a) and 1(b), the metal support 10, anode 20, and electrolyte layer 30 may have hexagonal shapes of substantially the same size in plan view, and the cathode 40 and current collector 50 may have hexagonal shapes smaller than the hexagonal shape.

[0018] The metal support 10 is a porous body, has gas permeability, and is a member capable of supporting the anode 20, electrolyte layer 30, cathode 40, and current collector 50. The metal support 10 is a metal porous body mainly composed of a metal, for example, ferritic stainless steel or the like. By using ferritic stainless steel, the thermal expansion coefficient of the metal support 10 can be made close to the thermal expansion coefficient of the electrolyte layer 30. Further, it is preferable that the metal support 10 is composed only of a metal component. This is because the thermal shock resistance, mechanical shock resistance, etc. of the metal support 10 can be improved. The thickness of the metal support 10 is, for example, 50 μm or more and 500 μm or less, or 75 μm or more and 300 μm or less, or 100 μm or more and 200 μm or less. For example, the metal support 10 can be obtained by sintering a powder material.

[0019] The anode 20 is a porous electrode having electrode activity as an anode, and contains an oxide ion conductive ceramic and a Ni component. The Ni component may be contained as metallic Ni, or may be contained as an oxide such as NiO. Since NiO is reduced by hydrogen gas during the use of the fuel cell 100, it comes to exist as metallic Ni. Metallic Ni has functions of electron conduction and an anode catalyst.

[0020] Furthermore, the electrode framework of the anode 20 contains oxide ion conductive ceramics. Oxide ion conductive ceramics include ScYSZ. For example, it is preferable to use ScYSZ having a composition range of 5 mol% to 16 mol% of scandia (Sc2O3) and 1 mol% to 3 mol% of yttria (Y2O3). ScYSZ with a combined amount of scandia and yttria of 6 mol% to 15 mol% is even more preferable, as this composition range provides the highest oxide ion conductivity. Note that oxide ion conductive ceramics are, for example, materials with an oxide ion transport fraction of 99% or more. GDC may be used as the oxide ion conductive ceramic. For example, the same solid oxide contained in the electrolyte layer 30 may be used as the oxide ion conductive ceramic.

[0021] The thickness of the anode 20 is, for example, 2 μm to 30 μm, or 10 μm to 20 μm, or 10 μm to 15 μm. For example, the anode 20 can be obtained by sintering a powder material.

[0022] The electrolyte layer 30 is a dense layer with gas impermeability, mainly composed of a solid oxide having oxide ion conductivity. Preferably, the electrolyte layer 30 is mainly composed of ZrO2-based ceramics such as scandia-yttria stabilized zirconium oxide (ScYSZ) or YSZ (yttria stabilized zirconium oxide), or GDC (Gd-doped ceria) in which gd (gadolinium) is doped into CeO2. When using ScYSZ, the oxide ion conductivity is highest when the concentration of Y2O3 + Sc2O3 is between 6 mol% and 15 mol%, and it is desirable to use a material with this composition. The thickness of the electrolyte layer 30 is, for example, 0.01 μm to 100 μm, or 0.1 μm to 50 μm, or 1 μm to 20 μm. For example, the electrolyte layer 30 can be obtained by sintering powder material.

[0023] The metal support 10, anode 20, and electrolyte layer 30 may be sintered individually, or the three layers of green sheets may be laminated and sintered together before firing.

[0024] The cathode 40 is an electrode that has electrode activity as a cathode and possesses electronic conductivity and oxide ion conductivity. For example, the cathode 40 mainly consists of a ceramic material that has electronic conductivity and oxide ion conductivity. As the ceramic material, for example, LaCoO3-based materials, LaMnO3-based materials, LaFeO3-based materials, etc., can be used. For example, as the LaCoO3-based material, LSC (lanthanum strontium cobaltite) can be used. LSC is LaCoO3 doped with Sr (strontium). The thickness of the cathode 40 is, for example, 1 μm to 200 μm, or 5 μm to 150 μm, or 10 μm to 100 μm. For example, the cathode 40 can be obtained by sintering a powder material, or by coating a liquid material and drying it.

[0025] The current collector 50 is not particularly limited as long as it is made of a conductive material, but for example, it is a metal foil such as silver. The current collector 50 may also be a thin film of a sintered body made of sintered metal powder. It is preferable that the current collector 50 has through holes so that the oxidizing gas can pass through. The thickness of the current collector 50 is, for example, 1 μm to 200 μm, or 5 μm to 100 μm, or 10 μm to 50 μm.

[0026] The fuel cell unit 100 generates electricity through the following process. The fuel cell unit 100 uses an oxidizing gas containing oxygen, such as air, and a fuel gas containing hydrogen, such as hydrogen gas or reformed gas, as the reaction gases. The oxidizing gas is supplied to the cathode 40. At the cathode 40, due to the effect of the electrode activity of the cathode 40, the oxygen that reaches the cathode 40 reacts with electrons supplied from the external electrical circuit to form oxide ions. The oxide ions conduct through the electrolyte layer 30 and move to the anode 20 side. Meanwhile, the fuel gas is supplied to the anode 20. The fuel gas reaches the anode 20 via the metal support 10. The hydrogen that reaches the anode 20 releases electrons at the anode 20 due to the effect of the electrode activity of the anode 20, and reacts with oxide ions conducting through the electrolyte layer 30 from the cathode 40 side to form water (H2O). The released electrons are removed to the outside by the external electrical circuit. Electrons extracted to the outside perform electrical work before being supplied to the cathode 40. Through this process, electricity is generated.

[0027] Next, the interconnector 110 in which the fuel cell unit 100 is arranged will be described. Figure 2(a) is a perspective view of the interconnector 110. As illustrated in Figure 2(a), the interconnector 110 is provided with a power generation gas flow path 111 in the central region, which consists of a recess having a hexagonal shape in plan view. The power generation gas flow path 111 has a hexagonal shape that is approximately the same size as the metal support 10. An introduction flow path 112 formed in the shape of a groove is provided around the power generation gas flow path 111. The introduction flow path 112 extends to the first corner portion 113 of the power generation gas flow path 111, which has a hexagonal shape in plan view. An exhaust flow path 115 for fuel gas is provided, formed in the shape of a groove, from the second corner portion 114, which is diagonally opposite the first corner portion 113, to the side surface of the interconnector 110.

[0028] Furthermore, a through-hole is formed that functions as a fuel gas inlet 116. The introduction channel 112 extends from the fuel gas inlet 116 to the first corner 113. In the power generation gas channel 111, an exhaust channel 115 is provided from the second corner 114, which is diagonally opposite the first corner 113, to the side of the interconnector 110. A gap 117 is formed in the interconnector 110 so as to surround the power generation gas channel 111. The gap 117 functions as an insulating material. The gap 117 may be an air gap, or it may be filled with a material that has a lower thermal conductivity than the interconnector 110.

[0029] Figure 2(b) illustrates an intermediate member 140 for being placed on top of the interconnector 110. As illustrated in Figure 2(b), the intermediate member 140 has substantially the same shape as the interconnector 110. The intermediate member 140 is placed on top of the interconnector 110 via a glass seal that has the same shape as the intermediate member 140. This prevents the fuel gas flowing through the introduction channel 112, the power generation gas channel 111, and the discharge channel 115 from mixing with the oxidizer gas. From the viewpoint of preventing contact between the fuel gas and the oxidizer gas, it is preferable that the glass seal extends to the peripheral edge of the upper surface of the electrolyte layer 30.

[0030] Figure 2(c) is a perspective view of the lid member 120. As illustrated in Figure 2(c), the lid member 120 has a power generation gas channel 121 in its central region, which is a recess having a hexagonal shape in plan view. Around the power generation gas channel 121, there is an introduction channel 122 for oxidizer gas, which is formed in a groove shape. The introduction channel 122 extends to the first corner 123 of the power generation gas channel 121, which has a hexagonal shape in plan view. An exhaust channel 125 for oxidizer gas, which is formed in a groove shape, is provided from the second corner 124, which is diagonally opposite the first corner 123, to the side surface of the lid member 120.

[0031] Furthermore, a through-hole is formed that functions as an oxidizer gas inlet 126. The introduction channel 122 extends from the oxidizer gas inlet 126 to the first corner 123. In the power generation gas channel 121, an exhaust channel 125 is provided from the second corner 124, which is diagonally opposite the first corner 123, to the side surface of the lid member 120. A gap 127 is formed in the lid member 120 so as to surround the power generation gas channel 121. The gap 127 functions as an insulating material. The gap 127 may be an air gap, or it may be filled with a material that has a lower thermal conductivity than the lid member 120.

[0032] Figure 3 is a cross-sectional view of the fuel cell 200 in this embodiment. In this embodiment, the fuel cell unit 100 described in Figure 1 is placed in the power generation gas flow path 111. For example, the fuel cell unit 100 is placed via a current collector 90 located on the bottom surface of the power generation gas flow path 111. To allow fuel gas to flow through the power generation gas flow path 111, the current collector 90 can be made of materials such as those with through holes, porous materials, or mesh materials. When the gap 127 functions as an insulating material, heat escapes to the outside through the beam portion that does not contain the gap 127. Reducing the cross-sectional area of ​​the beam improves the insulating properties. Inside the beam, the inlet flow path and the outlet flow path are in close proximity, which has the effect of efficiently exchanging heat between the heat escaping to the outside and the fuel gas and exhaust gas.

[0033] Next, we will explain the flow of reaction gas in the power generation gas flow path. In a fuel cell that has a circular shape in plan view, the power generation gas flow path 401 will also have a roughly circular shape in plan view, as illustrated in Figure 4. In this case, the area over which the fuel gas flows in contact with the fuel cell is the area enclosed by curvature a and curvature b. In this case, the area contributing to power generation is smaller compared to the case where the fuel gas flow path has a hexagonal shape in plan view. This is for the following reasons. Reason 1: In the case of a circle, the inlet angle becomes large relative to the flow at the inlet, creating vortices and resulting in areas where fuel gas cannot be supplied. Vortices are simply a situation where the same molecules are rotating. Reason 2: In the case of a circle, the flow follows the wall of the circle and always bends. When it bends, pressure loss occurs and the flow velocity at the wall decreases. A slow flow velocity increases the concentration overpotential, which is a cause of the problem. The streamlines of a hexagon are generally linear, resulting in less pressure loss.

[0034] In contrast, in the fuel cell unit 100 according to this embodiment, which has a hexagonal shape in plan view, the power generation gas flow path 111 also has a hexagonal shape in plan view, as illustrated in Figure 5. In this case, the shape of the power generation gas flow path 111 can be made nearly symmetrical. Also, since the inflow angle can be made smaller compared to a circular or square shape, the vortex that remains near the inlet can be reduced. Furthermore, since there are two hexagonal sides parallel to the inlet and outlet, the streamlines move in a linear fashion, reducing turbulence and pressure loss. For these reasons, the generation of turbulence can be suppressed, and the gas flows evenly. As a result, power generation efficiency can be improved.

[0035] Furthermore, if the fuel cell unit 100 starts generating power and its temperature rises rapidly, there is a risk of cracking in the ceramic layers (anode 20, electrolyte layer 30, and cathode 40). However, since the ceramic layers are supported by a flexible metal support 10, cracking can be suppressed. In particular, if any of the ceramic layers have a hexagonal shape, cracking is likely to occur at the corners of the hexagon, but this can be suppressed by supporting them with the metal support 10.

[0036] From the above, the fuel cell 200 according to this embodiment has the unique effect of being able to increase the amount of power generated while suppressing cracking. For example, even if it is rapidly started up in 1 minute or more and 5 minutes or less and reaches the desired amount of power generated, cracking can be suppressed. For example, even if a temperature difference of 50°C or more and 200°C or less occurs within the plane of the fuel cell unit 100 during rapid startup, cracking can be suppressed.

[0037] Furthermore, the metal support 10 is subjected to a temperature increase of 0.16 (W / m·℃) × 102 Above, 0.27(W / m・℃)×10 2 It is preferable that the following thermal conductivity is present.

[0038] (Second Embodiment) Next, a second embodiment will be described. First, prior to describing the second embodiment, for comparison, a case in which a fuel cell unit 300 having a circular shape in plan view is positioned on an interconnector 410 having a circular shape of the same size to constitute a fuel cell will be described. As illustrated in Figure 6(a), a plurality of positioning blocks 400 are arranged on the outer circumference of the interconnector 410, protruding above the upper surface of the interconnector 410. The positioning blocks 400 have a substantially rectangular parallelepiped shape as an example. In the example in Figure 6(a), three positioning blocks 400 are arranged.

[0039] Figure 6(b) is a plan view of the fuel cell unit 300 mounted on the interconnector 410. In Figure 6(b), one positioning block 400 is shown in a magnified view. As illustrated in Figure 6(b), the contact between each positioning block 400 and the fuel cell unit 300 is a point contact in plan view. Because the position of the fuel cell unit 300 is not easily fixed with point contact, the fuel cell unit 300 is prone to movement, and misalignment between the fuel cell unit 300 and the interconnector 410 is likely to occur. In Figure 6(b), misalignment has occurred between the fuel cell unit 300 and the interconnector 410.

[0040] In contrast, we will now describe a case in which a fuel cell unit 100, which has a hexagonal shape in plan view as explained in Figure 1, is positioned on an interconnector 110a having a hexagonal shape of the same size to constitute a fuel cell 200a. As illustrated in Figure 7(a), multiple positioning blocks 400 are arranged on the outer circumference of the interconnector 110a, protruding above the upper surface of the interconnector 110a. In the example in Figure 7(a), three positioning blocks 400 are arranged.

[0041] Figure 7(b) is a plan view of the fuel cell unit 100 mounted on the interconnector 110a. In Figure 7(c), one positioning block 400 is shown in a magnified view. Since the fuel cell unit 100 has a hexagonal shape that is approximately the same size as the interconnector 110a in plan view, the contact between each positioning block 400 and the fuel cell unit 100 is a line contact in plan view, as illustrated in Figure 7(b). Line contact makes it easier to fix the position of the fuel cell unit 100, so the fuel cell unit 100 is less likely to move, and positional misalignment between the fuel cell unit 100 and the interconnector 110a is less likely to occur. Thus, the fuel cell 200a according to this embodiment has the unique effect of being able to be positioned with high precision.

[0042] Furthermore, since the fuel cell 200a according to this embodiment has a hexagonal shape in plan view, its six sides are flat surfaces. In this case, as illustrated in Figure 8, the robot 500 that applies the liquid glass seal 130 can apply the liquid glass seal 130 with high precision to each side surface of the interconnector 110a and the fuel cell unit 100. This eliminates the need to secure an area for applying the glass seal 130 to the periphery of the interconnector 110a, thereby increasing the area that contributes to power generation. The glass seal 130 functions as a sealing member after drying.

[0043] Figure 9(a) is a cross-sectional view of the fuel cell unit 100 when the glass seal 130 is applied to the side surface. In this embodiment, as an example, the side surface of the interconnector 110a, the side surface of the metal support 10, the side surface of the anode 20, and the side surface of the electrolyte layer 30 are substantially the same. The interconnector 110a has the shape described in Figure 5 and has a hexagonal shape that is substantially the same size as the metal support 10 in plan view. The glass seal 130 is applied to these side surfaces. The glass seal 130 may extend to the peripheral edge of the upper surface of the electrolyte layer 30. In this case, the lid member 120a can be fixed to the fuel cell unit 100. As illustrated in Figure 9(b), the lid member 120a is provided with a power generation gas flow path 121 in the central region, which is a recess having a hexagonal shape in plan view. Around the power generation gas flow path 121, an introduction flow path 122 for oxidizer gas, formed in a groove shape, is provided. The introduction channel 122 extends to the first corner 123 of the hexagonal power generation gas channel 121 in plan view. A groove-shaped discharge channel 125 for oxidizer gas is provided from the second corner 124, which is diagonally opposite the first corner 123, to the side of the lid member 120. The lid member 120a is inverted vertically and horizontally and placed on top of the fuel cell unit 100. In this case, the position of the first corner 113 corresponds to the position of the first corner 123, and the position of the second corner 114 corresponds to the position of the second corner 124.

[0044] Furthermore, the anode wiring can be connected to the anode 20 via the discharge channel 115. Also, the cathode wiring can be connected to the cathode 40 via the discharge channel 125.

[0045] In this embodiment as well, since the fuel cell unit 100 has a hexagonal shape in plan view, the power generation gas flow path 111 also has a hexagonal shape in plan view, as illustrated in Figure 5. In this case, the shape of the power generation gas flow path 111 can be made nearly symmetrical. Also, since the inflow angle can be made smaller compared to a circular or square shape, the vortex that accumulates near the inlet can be reduced. Furthermore, since there are two hexagonal sides parallel to the inlet and outlet, the streamlines move linearly, reducing turbulence and pressure loss. For these reasons, the generation of turbulence can be suppressed and the gas flows evenly. As a result, the power generation efficiency can be improved. In addition, since the ceramic layer is supported by a flexible metal support 10, cracking can be suppressed. [Examples]

[0046] A fuel cell was fabricated according to the second embodiment described above.

[0047] (Example 1) A fuel cell 200a, illustrated in Figure 9(a), was fabricated. The interconnector 110a was a regular hexagon with a side length of 12 mm in plan view. In plan view, the metal support 10, anode 20, and electrolyte layer 30 were the same shape as the interconnector 110a. Alignment was performed as illustrated in Figure 7(a), and the glass seal 130 was applied as illustrated in Figure 8. Fuel gas and oxidizer gas were flowed to allow the fuel cell unit 100 to generate electricity. No cracks occurred even when the temperature was rapidly raised to 600°C in 5 minutes. This is because the metal support 10 was provided. The electromotive force was about 1V, confirming that electricity could be generated. The amount of electricity generated was 0.3W. This is because by making the fuel cell unit 100 hexagonal in plan view, the area of ​​the region contributing to power generation could be increased.

[0048] (Comparative Example 1) An interconnector 410, illustrated in Figure 4, was fabricated. The interconnector 410 had a disc shape with a diameter of 22 mm in plan view. The fuel cell unit 100, illustrated in Figure 1(a), was made into a fuel cell 300 having a circular shape in plan view. A glass seal was applied to the peripheral edge of the upper surface of the interconnector 410, and alignment was performed as illustrated in Figure 6(a). Fuel gas and oxidizer gas were flowed to cause the fuel cell 300 to generate electricity. No cracks occurred even when the temperature was rapidly raised to 600°C in 5 minutes. This is thought to be because a metal support 10 was provided. The electromotive force was about 1V, confirming that electricity could be generated. However, the amount of electricity generated was 0.1W. This is because the area of ​​the region contributing to power generation could not be increased by making the fuel cell 300 circular in plan view.

[0049] (Comparative Example 2) A fuel cell with the shape illustrated in Figure 9(a) was fabricated. The interconnector was a regular hexagon with a side length of 12 mm in plan view. In addition, a ceramic support was used instead of a metal support in the fuel cell unit 100 illustrated in Figures 1(a) and 1(b). In plan view, the shapes of the ceramic support, anode, and electrolyte layer were the same as those of the interconnector. Alignment was performed as illustrated in Figure 7(a), and a glass seal 130 was applied as illustrated in Figure 8. Fuel gas and oxidizer gas were flowed to generate electricity in the fuel cell. The electromotive force was approximately 0.2V, which was insufficient for power generation. When power generation was stopped and the fuel cell was removed and inspected, cracks and fractures were found. This is thought to be due to the use of a ceramic support.

[0050] (Comparative Example 3) An interconnector 410, as illustrated in Figure 4, was fabricated. The interconnector 410 had a disc shape with a diameter of 22 mm in plan view. The fuel cell unit 100, as illustrated in Figure 1(a), was converted into a fuel cell 300 with a circular shape in plan view. Alignment was performed as illustrated in Figure 7(a). After that, a glass seal was applied to the side surface. A total of 10 samples were fabricated. Fuel gas and oxidizer gas were flowed through the fuel cell 300 to generate electricity. Of the 10 samples, two produced an electromotive force of approximately 1V, confirming that they could generate electricity. However, no electromotive force was obtained from the remaining eight. This is thought to be because a sealing defect occurred due to the application of the glass seal to the side surface of the disc shape.

[0051] From these results, it was confirmed that by using a fuel cell with a hexagonal shape in plan view and supported by a metal support, it is possible to increase power generation while suppressing cracking.

[0052] Although embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims. [Explanation of Symbols]

[0053] 10 Metal support 20 anodes 30 Electrolyte layer 40 Cathode 50 Current collector 100 fuel cell units 110 Interconnector 111 Gas flow path for power generation 112 Inlet channel 113 1st corner 114 Second corner 115 Discharge channel 116 Fuel gas inlet 117 Gap 120 Lid member 121 Gas flow path for power generation 122 Inlet channel 123 1st corner 124 Second corner 125 Discharge channel 126 Oxidizer gas inlet 127 gaps 130 Glass Seal 140 Intermediate member 200 Fuel Cell

Claims

1. A metal support and A first electrode, mainly composed of ceramics, is provided on the aforementioned metal support, An oxide-type solid electrolyte layer provided on the first electrode, The solid electrolyte layer is provided with a second electrode having a different polarity from the first electrode and mainly composed of ceramics, A fuel cell in which the metal support, the first electrode, and the solid electrolyte layer have a hexagonal shape of substantially the same size in a plan view.

2. The aforementioned metal support has a temperature of 0.16 (W / m·℃) × 10 ２ Above, 0.27 (W / m・℃)×10 ２ The fuel cell according to claim 1, having the following thermal conductivity.

3. The metal support is provided with an interconnector on the main surface opposite to the first electrode, The fuel cell according to claim 1, wherein a reaction gas channel is provided on the main surface of the interconnector on the metal support side.

4. The reaction gas channel includes a power generation gas channel for supplying the reaction gas to the first electrode. The aforementioned gas flow path for power generation has a hexagonal shape that is approximately the same size as the metal support. The fuel cell according to claim 3, wherein the reaction gas flow path comprises an introduction flow path leading to the first hexagonal corner of the power generation gas flow path, and an exhaust flow path for discharging the reaction gas from a second corner facing the first hexagonal corner.

5. The fuel cell according to claim 3, wherein the interconnector has a hexagonal shape in plan view that is substantially the same size as the metal support.

6. The reaction gas flow path comprises a power generation gas flow path for supplying the reaction gas to the first electrode in the center of the interconnector, and an introduction flow path formed around the power generation gas flow path for introducing the reaction gas into the power generation gas flow path. The power generation gas flow path has a hexagonal shape in a plan view relative to the interconnector. The introduction channel is connected to the first corner of the hexagonal shape of the power generation gas channel, The fuel cell according to claim 5, wherein the reaction gas flow path includes a discharge flow path for discharging the reaction gas from a second corner of the hexagonal gas flow path that is opposite to the first corner of the hexagonal shape.

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