Fuel cell and method of manufacturing fuel cell
The fuel cell design with interconnectors and parallel flow path members addresses gas flow and current conduction issues, resulting in increased efficiency by ensuring uniform gas distribution and enhanced flow rates.
Patent Information
- Application Number
- JP2023221389
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-12-27
- Publication Date
- 2025-07-09
AI Technical Summary
Existing fuel cells face challenges in ensuring uniform gas flow and current conduction paths due to limitations in the formation of current collecting protrusions and gas supply holes, leading to reduced power generation efficiency.
A fuel cell design featuring interconnectors and parallel flow path members with specific contact portions and connecting structures that enhance gas flow and current conduction paths, ensuring uniform gas distribution and increased flow rates across the entire cell stack.
The improved design increases gas flow rates and current conduction paths, thereby enhancing the power generation efficiency of the fuel cell stack.
Smart Images
Figure 2025103765000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a fuel cell and a method for manufacturing the fuel cell.
Background Art
[0002] Patent Document 1 discloses a fuel cell stack (fuel cell) in which a plurality of current collecting protrusions are formed upright on both surfaces of a separator between stacked power generation cells (single cells), and a gas flow path partitioned by the current collecting protrusions is formed between the single cell and the separator. In this fuel cell stack, since the current collecting protrusions are formed by cutting and raising them from a current collecting substrate of the separator, a gas supply hole for supplying gas from the gas flow path to the single cell is formed in the separator.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In the fuel cell described in Patent Document 1, a plurality of current collecting protrusions are formed by punching or the like, but the current collecting protrusions and the gas supply holes cannot be provided unless there is no joint of the current collecting substrate in the gas flow direction. Therefore, the current collecting protrusions and the gas supply holes cannot be ensured in the entire region in the gas flow direction, the gas flow rate to the power generation cell and the current conduction path in the stacking direction of the power generation cells become small, and there is a risk that the power generation efficiency decreases.
[0005] In view of the above problems, an object of the present invention is to provide a fuel cell with improved power generation efficiency and a method for manufacturing the fuel cell.
Means for Solving the Problems
[0006] According to one aspect of the present invention, a fuel cell in which a plurality of power generation cells are stacked is provided. Between each of the power generation cells, this fuel cell includes an interconnector provided separately from the power generation cells, and a plurality of flow path members arranged in parallel between the interconnector and the power generation cells. The interconnector and the flow path members form a gas flow path through which the gas supplied to the power generation cells flows. The power generation cell includes a porous metal support on at least one surface. The flow path member has a first contact portion that contacts the metal support and extends along the gas flow direction, a second contact portion that contacts the interconnector and extends along the gas flow direction, and a connecting portion that connects the first contact portion and the second contact portion. Further, the first contact portion is provided so as to be separated from the first contact portion of the adjacent flow path member, so that a gas circulation hole for supplying gas from the gas flow path to the power generation cell is formed between the first contact portion of the flow path member and the first contact portion of the adjacent flow path member.
Effect of the Invention
[0007] According to the present invention, a plurality of flow path members arranged in parallel between the interconnector and the power generation cell have a first contact portion that contacts the metal support of the power generation cell and extends along the gas flow direction, and a second contact portion that contacts the interconnector and extends along the gas flow direction. That is, since the flow path member connecting the power generation cell and the interconnector extends along the gas flow direction, the current conduction path in the stacking direction of the power generation cell can be increased. Further, since the first contact portion is provided so as to be separated from the first contact portion of the adjacent flow path member, the gas circulation path is formed in the entire region in the gas flow direction, and the gas circulation amount to the power generation cell is increased. Therefore, the power generation efficiency of the fuel cell is improved.
Brief Description of the Drawings
[0008]
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Embodiments for Carrying Out the Invention
[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like.
[0010] [First Embodiment] FIG. 1 is a schematic configuration diagram of a fuel cell stack (fuel cell) 100 according to the first embodiment, and is a partial cross-sectional view of two adjacent fuel cells (hereinafter also referred to as power generation cells) 1. The fuel cell stack 100 is configured by stacking a plurality of power generation cells 1. More specifically, the power generation cell 1 constitutes a power generation unit 10 together with an interconnector 2 and a flow path member 3 described later, and the fuel cell stack 100 is configured by stacking a plurality of power generation units 10. Each individual power generation cell 1 constituting the fuel cell stack 100 is, for example, a solid oxide fuel cell (SOFC), and generates power by receiving supply of a fuel gas (anode gas) and a cathode gas. In the present embodiment, the fuel cell stack 100 is premised on being mounted on a moving vehicle such as an electric vehicle or a hybrid vehicle, but may also be used as a power source for various electric devices and the like.
[0011] As shown in FIG. 1, an interconnector 2 and a flow path member 3 are provided between the plurality of stacked power generation cells 1, and the power generation cell 1, the interconnector 2, and the flow path member 3 constitute the power generation unit 10. Note that in FIG. 1, only two adjacent power generation units 10 among the plurality of stacked power generation units 10 are shown, but actually, more power generation units 10 can be stacked in the same manner. Also, for simplicity, in FIG. 1, the outer edge portion of the fuel cell stack 100 (power generation unit 10) is omitted, and only a part of the cross-section of two adjacent power generation units 10 is shown.
[0012] The power generation cell 1 is formed by forming a fuel electrode on one surface of a solid electrolyte (electrolyte) and an air electrode on the other surface (hereinafter, the fuel electrode and the air electrode are collectively also referred to as electrodes). In the present embodiment, the upper side in FIG. 1 is the air electrode and the lower side is the fuel electrode, but it is not limited to this. Also, the power generation cell 1 includes porous metal supports that support the fuel electrode and the air electrode on the fuel electrode side (the upper surface of the fuel electrode) and the air electrode side (the lower surface of the air electrode), respectively.
[0013] The interconnector 2 is made of ferritic stainless steel and is provided at a distance from the power generation cell 1 between two adjacent power generation cells 1 as shown in FIG. 1.
[0014] The flow path member 3 is a fin assembly made of ferritic stainless steel and is a current collector. The flow path member 3 is electrically connected to the electrodes of the power generation cell 1 and the interconnector 2, thereby forming a conductive path between the stacked power generation cells 1. Further, a plurality of the flow path members 3 are arranged in parallel between the power generation cell 1 and the interconnector 2 to form gas flow paths 4 and 5 between the interconnector 2 and the power generation cell 1.
[0015] More specifically, the flow path member 3 includes a plurality of fuel electrode side flow path members 3A arranged in parallel between the fuel electrode side of the power generation cell 1 and the interconnector 2, and a plurality of air electrode side flow path members 3B arranged in parallel between the air electrode side of the power generation cell 1 and the interconnector 2. Each flow path member 3 is configured as a Z-shaped member having a first contact portion 31 that contacts the metal support of the power generation cell 1, a second contact portion 32 that contacts the interconnector 2, and a connecting portion 33 that connects the first contact portion 31 and the second contact portion 32. Thereby, a plurality of spaces partitioned by the interconnector 2 and the fuel electrode side flow path member 3A are formed between the fuel electrode side of the power generation cell 1 and the interconnector 2. Also, a plurality of spaces partitioned by the interconnector 2 and the air electrode side flow path member 3B are formed between the air electrode side of the power generation cell 1 and the interconnector 2. Among these, the space partitioned by the interconnector 2 and the fuel electrode side flow path member 3A constitutes a fuel flow path (gas flow path) 4 through which fuel gas flows, and the space partitioned by the interconnector 2 and the air electrode side flow path member 3B constitutes an air flow path (gas flow path) 5 through which air (cathode gas) flows. The first contact portion 31 and the second contact portion 32 of the flow path member 3 extend from one end portion to the other end portion of the power generation unit 10 along the gas flow direction (see FIG. 3).
[0016] Further, in the flow path member 3, the first contact portion 31 that contacts the metal support of the power generation cell 1 is provided so as to be separated from the first contact portion 31 of the adjacent flow path member 3. Thereby, gas flow holes 41 and 51 through which gas can be supplied from the gas flow paths 4 and 5 to the power generation cell 1 are formed between the first contact portion 31 of the flow path member 3 and the first contact portion 31 of the adjacent flow path member 3. More specifically, a gas flow hole 41 for supplying fuel gas from the fuel flow path (gas flow path) 4 to the fuel electrode side of the power generation cell 1 is formed between the first contact portion 31 of the fuel electrode side flow path member 3A and the first contact portion 31 of the adjacent fuel electrode side flow path member 3A. Also, a gas flow hole 51 for supplying air (cathode gas) from the air flow path (gas flow path) 5 to the air electrode side of the power generation cell 1 is formed between the first contact portion 31 of the air electrode side flow path member 3B and the first contact portion 31 of the adjacent air electrode side flow path member 3B. In this way, fuel gas and air (cathode gas) are supplied to the power generation cell 1 from the gas flow paths 4 and 5 through the gas flow holes 41 and 51, whereby the power generation cell 1 generates power.
[0017] Note that the materials constituting the interconnector 2 and the flow path member 3 are not limited to the above, and any known materials may be used.
[0018] As described above, the fuel cell stack 100 generates power by supplying gas (fuel gas, air) to the power generation cell 1 from the gas flow paths 4 and 5 through the gas flow holes 41 and 51.
[0019] Incidentally, when a corrugated fin (so-called corrugated metal member) is used as a gas flow path member (flow channel) such as an SOFC stack, there will be a flow path portion where the power generation cell is in contact with the fuel gas and a flow path portion where they are not in contact. That is, as shown in FIG. 2, when a corrugated (concave-convex shaped) flow path member 63 is used, a flow path portion 64 where the power generation cell 61 is in contact with the fuel gas and a flow path portion 65 where the power generation cell 61 is not in contact with the fuel gas are formed. Here, in order to sufficiently ensure the flow rate of the fuel gas to the power generation cell 61, it is preferable to make the width of the flow path portion 65 where the power generation cell 61 is not in contact with the fuel gas as small as possible. However, ferritic stainless steel, which is the material of the flow path member, is difficult to press-process into a concave-convex shape, and the flow path portion 65 cannot be made sufficiently small. Further, for example, when gas flow holes are provided in the flow path portion 65 where the power generation cell 61 is not in contact with the fuel gas in order to increase the flow rate of the fuel gas to the power generation cell 61, the area where the flow path member 63 and the power generation cell 61 are in contact in the gas flow direction is reduced by the amount of the gas flow holes, and the electrical resistance increases, so that the current-carrying path in the stacking direction of the power generation cell 61 becomes small. Thus, when a corrugated fin is used, it is difficult to increase both the flow rate of the fuel gas and the current-carrying path, and there is a risk of a decrease in the power generation efficiency of the fuel cell stack.
[0020] Also, as in the aforementioned Patent Document 1, when the current collecting protrusion is lifted from the current collecting substrate of the separator to form the gas flow path and the gas supply hole, the current collecting protrusion and the gas supply hole cannot be provided without a joint of the current collecting substrate in the gas flow direction. Therefore, the current collecting protrusion and the gas supply hole cannot be ensured in the entire region in the gas flow direction, the flow rate of the gas to the power generation cell and the current-carrying path in the stacking direction of the power generation cell become small, and there is a risk of a decrease in the power generation efficiency.
[0021] In contrast, in the present embodiment, a plurality of flow path members 3 arranged in parallel between the interconnector 2 and the power generation cell 1 contact the metal support of the power generation cell 1 and have a first contact portion 31 extending along the gas flow direction and a second contact portion 32 contacting the interconnector 2 and extending along the gas flow direction. That is, since the flow path member 3 connecting the power generation cell 1 and the interconnector 2 extends along the gas flow direction, the current conduction path in the stacking direction of the power generation cell 1 can be increased. Further, the flow path member 3 is provided such that the first contact portion 31 is separated from the first contact portion 31 of the adjacent flow path member 3. For this reason, the gas flow holes 41 and 51 are formed in the entire region in the gas flow direction, and the gas flow rate to the power generation cell 1 is increased. Thus, since the current conduction path in the stacking direction of the power generation cell 1 and the gas flow rate to the power generation cell 1 can be increased, the power generation efficiency of the fuel cell stack 100 is improved.
[0022] Hereinafter, the details of the flow path member 3 will be described.
[0023] As described above, the flow path member 3 includes a fuel electrode side flow path member 3A between the fuel electrode side of the power generation cell 1 and the interconnector 2 and an air electrode side flow path member 3B between the air electrode side of the power generation cell 1 and the interconnector 2. As shown in FIG. 1, each flow path member 3 has a first contact portion 31 contacting the metal support of the power generation cell 1, a second contact portion 32 contacting the interconnector 2, and a connecting portion 33 connecting the first contact portion 31 and the second contact portion 32.
[0024] The fuel electrode side flow path member 3A is welded to the metal support of the power generation cell 1 at the first contact portion 31 and is welded to the interconnector 2 at the second contact portion 32. Further, the air electrode side flow path member 3B is welded to the metal support of the power generation cell 1 at the first contact portion 31. Thereby, a power generation unit 10 composed of the power generation cell 1, the interconnector 2, and the flow path members 3A and 3B is configured. The power generation units 10 are diffusion-bonded to the adjacent power generation units 10 in the stacking direction. Specifically, in the power generation unit 10, the air electrode side flow path member 3B is diffusion-bonded to the interconnector 2 of the power generation unit 10 adjacent in the stacking direction at the second contact portion 32. Note that a bonding material 6 is interposed between the air electrode side flow path member 3B and the interconnector 2. As the bonding material 6, copper, nickel, platinum, gold, etc. can be used, but it is not limited thereto. Welding is not used as the bonding method between the air electrode side flow path member 3B and the interconnector 2 because the welding machine cannot access the contact portion between the interconnector 2 and the air electrode side flow path member 3B when the power generation units 10 are in contact with each other.
[0025] FIG. 3 is a plan view of the flow path member 3 as viewed from the second contact portion 32 side. Further, FIG. 4 is (a) a cross-sectional view taken along line A-A of FIG. 3, (b) a cross-sectional view taken along line B-B of FIG. 3, and (c) a cross-sectional view taken along line C-C of FIG. 3. Note that FIGS. 3 to 4 are described for the fuel electrode side flow path member (flow path member) 3A, but the following description also holds for the air electrode side flow path member (flow path member) 3B in the same manner.
[0026] The arrows shown in FIGS. 3 and 4(c) indicate the direction in which the (fuel) gas flows. In FIG. 3, the (fuel) gas flows in the vertical direction. Also, as shown in FIG. 4(c), the fuel gas in the gas flow path 4 flows through the gas flow path 4 while supplying the fuel gas to the power generation cell 1. As shown in FIG. 3, in the flow path member 3, the first contact portion 31 and the second contact portion 32 extend along the gas flow direction from one end to the other end of the power generation unit 10. In the first contact portion 31, a welding line 311 is formed along the gas flow direction, by which the flow path member 3 is welded to the metal support of the power generation cell 1. Thus, since the first contact portion 31 extends along the gas flow direction from one end to the other end of the power generation unit 10, the first contact portion 31 can be welded to the metal support of the power generation cell 1 in almost the entire region in the gas flow direction. Therefore, the current path of the power generation cell 1 can be increased.
[0027] As shown in FIGS. 3 and 4(a), the first contact portion 31 is provided so as to be separated from the first contact portion 31 of the adjacent flow path member 3, whereby the gas flow holes 41 are formed in the entire region in the gas flow direction. Therefore, the flow rate of the (fuel) gas supplied from the gas flow path 4 to the power generation cell 1 increases.
[0028] Also, as shown in FIG. 3, each flow path member 3 includes a plurality of joints 34 that connect to adjacent flow path members 3 intersecting the gas flow direction. In the present embodiment, each flow path member 3 includes joints 34 at both ends and the central portion in the gas flow direction (the direction of the arrow in FIG. 3) of the flow path member 3. As shown in FIGS. 3 and 4(b), the joint 34 extends from the second contact portion 32 of each flow path member 3 in a direction intersecting the gas flow direction. That is, the joint 34 is provided on the side in contact with the interconnector 2 of the flow path member 3. Therefore, the area of the gas flow hole 41 is not reduced by the joint 34. Thus, since the joint 34 is provided on the side of the interconnector 2, the gas flow to the power generation cell 1 is not blocked, and the gas flow rate to the power generation cell 1 can be increased. Also, since the joint 34 is provided on the side of the interconnector 2, the work when welding the flow path member 3 to the metal support is facilitated compared to the case where the joint 34 is provided on the side of the flow path member 3 in contact with the metal support of the power generation cell 1.
[0029] Also, as will be described later, the tip portion 341 of the joint 34 is bent, and the bent tip portion 341 is fitted into the fitting portion 321 (see FIGS. 5 and 6) provided in the second contact portion 32. Thereby, adjacent flow path members 3 are connected, the flow path member 3 is more fixed, and the positioning of the flow path member 3 becomes easy. As shown in FIG. 4(b), since the length of the joint 34 in the direction intersecting the gas flow direction is longer than the length d1 of the first contact portion 31 in the gas flow direction, each flow path member 3 has the first contact portion 31 spaced apart and fixed from the first contact portion 31 of the adjacent flow path member 3. Thereby, at the first contact portion 31, the flow path member 3 can be welded to the metal support of the power generation cell 1, and the gas flow hole 41 between the first contact portions 31 capable of supplying gas to the power generation cell 1 can be formed.
[0030] Also, as shown in FIGS. 4(b) and 4(c), each flow path member 3 is provided such that the length d1 of the first contact portion 31 in the direction intersecting the gas flow direction is equal to or less than the length d2 of the gas flow hole 41 in the direction intersecting the gas flow direction. Thereby, the flow rate of the (fuel) gas supplied from the gas flow path 4 to the power generation cell 1 can be increased.
[0031] FIG. 5 is a plan view of the flow path member 3 as viewed from the second contact portion 32 side, and FIG. 6 is a cross-sectional view taken along line A-A of FIG. 5.
[0032] As shown in FIG. 5, a fitting portion 321, which is a notch that fits with the tip portion 341 of the joint 34, is formed in the second contact portion 32 of the flow path member 3. As described above, the tip portion 341 of the joint 34 is bent, and by fitting the bent tip portion 341 into the fitting portion 321 of the flow path member 3, adjacent flow path members 3 are connected and positioned (see FIG. 6). Note that the fitting method between the joint 34 and the flow path member 3 may be to fit the bent tip portion 341 of the joint 34 into the fitting portion 321, or after combining the joint 34 with the second contact portion 32 of the flow path member 3, the tip portion 341 of the joint 34 may be struck from above to bend and fit the tip portion 341.
[0033] FIG. 7 is a diagram for explaining an example of the installation method of the flow path member 3.
[0034] As shown in FIG. 7, first, the flow path member 3 is (i) connected one by one using the joint 34, and (ii) placed on the metal support of the power generation cell 1, and the first contact portion 31 is welded to the metal support by a welding machine from the space 42 formed between the second contact portions 32 of the flow path member 3. Thereby, the flow path member 3 is installed in the power generation cell 1. In this way, by connecting a plurality of flow path members 3 and then welding them to the metal support of the power generation cell 1, the flow path member 3 can be installed in the same manner as welding a corrugated flow path member to the metal support in the conventional manner.
[0035] Note that the installation method of the above-described flow path member 3 is merely an example and is not limited thereto. For example, as shown in FIG. 7, instead of connecting the flow path members 3 and then welding them, the welding and connection of the flow path members 3 may be repeated one by one for installation. That is, as shown in FIG. 8, (i) one flow path member 3 is welded to the metal support of the power generation cell 1, (ii) the flow path member 3 adjacent to the welded flow path member 3 is connected using the joint 34, the connected flow path member 3 is welded, (iii) the steps (i) and (ii) are repeated, and (iv) a plurality of flow path members 3 may be installed on the power generation cell 1. When the flow path member 3 is installed by the method shown in FIG. 8, even if no space 42 is provided between the second contact portions 32 of the flow path members 3, the flow path member 3 can be installed on the power generation cell 1 by welding. Further, since it is not necessary to insert a welding machine into the space 42 for welding, the welding operation becomes easy, and the length in the direction intersecting the gas flow direction of the first contact portion 31 can be shortened. Thereby, the gas flow holes 41, 51 can be enlarged, and the flow rate of the gas supplied from the gas flow paths 4, 5 to the power generation cell 1 can be increased.
[0036] FIG. 9 is a diagram for explaining an example of a method for manufacturing a fuel cell stack 100.
[0037] As shown in FIG. 9, in the fuel cell stack 100, first, (i) a plurality of flow path members 3 (first contact portions 31) are welded to the metal supports on both sides of the power generation cell 1. In FIG. 9, it is assumed that the air electrode side flow path member 3B is installed on the upper surface side of the power generation cell 1 and the fuel electrode side flow path member 3A is installed on the lower surface side, but this is not limiting, and the upper and lower sides may be reversed. Next, (ii) the second contact portion 32 of the fuel electrode side flow path member 3A is welded to the interconnector 2. Thereby, the power generation unit 10 including the power generation cell 1, the interconnector 2, and the flow path member 3 is manufactured.
[0038] Next, (iii) a bonding material 6 made of, for example, copper is placed on the second contact portion 32 of the air electrode side flow path member 3B, and (iv) another power generation unit 10 is stacked on the bonding material 6 such that the bonding material 6 and the interconnector 2 are in contact with each other. Then, (v) the second contact portion 32 of the air electrode side flow path member 3B and the interconnector 2 are diffusion bonded with the bonding material 6, thereby manufacturing a fuel cell stack 100 in which two power generation units 10 are stacked. As described above, the second contact portion 32 and the interconnector 2 are diffusion bonded instead of welded because a welding machine cannot access the contact portion between the interconnector 2 and the air electrode side flow path member 3B when the power generation units 10 are in contact with each other.
[0039] In the example of FIG. 9, a manufacturing method of stacking two power generation units 10 has been described. However, by repeating the above steps (i) to (v), more power generation units 10 can be stacked. The number of power generation units 10 to be stacked can be arbitrarily determined.
[0040] Further, in (ii) of FIG. 9, when the air electrode side flow path member 3B is joined to the interconnector 2 via the bonding material 6, the angle formed by the second contact portion 32 and the connecting portion 33 is 90°. Preferably, however, the angle formed by the second contact portion 32 and the connecting portion 33 is an obtuse angle. That is, preferably, when the flow path member 3 is joined to the interconnector 2, the angle formed by the second contact portion 32 and the connecting portion 33 is an obtuse angle. Thereby, when stacking the power generation units 10 adjacent to each other on the second contact portion 32, the pressure in the stacking direction can be absorbed. Therefore, the bonding area between the second contact portion 32 and the interconnector 2 can be increased, and the current conduction path of the fuel cell 1 can be enlarged.
[0041] According to the fuel cell stack (fuel cell) 100 of the first embodiment described above, the following effects can be obtained.
[0042] The fuel cell stack (fuel cell) 100 includes a plurality of flow path members 3 arranged in parallel between the interconnector 2 and the power generation cell 1. The flow path members 3 are in contact with the metal support of the power generation cell 1 and have a first contact portion 31 extending along the gas flow direction, and a second contact portion 32 in contact with the interconnector 2 and extending along the gas flow direction. That is, since the flow path member 3 connecting the power generation cell 1 and the interconnector 2 extends along the gas flow direction, the current conduction path in the stacking direction of the power generation cell 1 can be increased. Further, the flow path member 3 is provided such that the first contact portion 31 is spaced apart from the first contact portion 31 of the adjacent flow path member 3. For this reason, the gas flow holes 41, 51 are formed in the entire region in the gas flow direction, and the gas flow rate to the power generation cell 1 is increased. Thus, since the current conduction path in the stacking direction of the power generation cell 1 and the gas flow rate to the power generation cell 1 can be increased, the power generation efficiency of the fuel cell stack 100 is improved.
[0043] The fuel cell stack (fuel cell) 100 includes a joint 34 in which the flow path member 3 is connected to an adjacent flow path member 3 intersecting the gas flow direction. Thereby, the flow path member 3 is more fixed, and the positioning of the flow path member 3 becomes easy. Further, the fuel cell stack 100 can be manufactured with the flow path members 3 connected by the joints 34, and the manufacture of the fuel cell stack 100 becomes easy.
[0044] The fuel cell stack (fuel cell) 100 includes a plurality of joints 34 in the flow path member 3. Thereby, the flow path member 3 is further fixed, and the positioning of the flow path member 3 becomes even easier.
[0045] The fuel cell stack (fuel cell) 100 is configured such that the joint 34 extends in a direction intersecting the gas flow direction from the second contact portion 32. That is, the joint 34 is provided on the side in contact with the interconnector 2 of the flow path member 3. Therefore, the area of the gas flow hole 41 is not reduced by the joint 34. That is, since the joint 34 is provided on the side of the interconnector 2, the gas flow rate to the power generation cell 1 increases. Further, since the joint 34 is provided on the side of the interconnector 2, the work when welding the flow path member 3 to the metal support of the power generation cell 1 becomes easier compared to the case where the joint 34 is provided on the side in contact with the metal support of the power generation cell 1 of the flow path member 3.
[0046] The fuel cell stack (fuel cell) 100 is such that the length of the joint 34 in the direction intersecting the gas flow direction is longer than the length of the first contact portion 31 in the direction intersecting the gas flow direction. Thereby, in each flow path member 3, the first contact portion 31 is fixed while being separated from the first contact portion 31 of the adjacent flow path member 3. Therefore, at the first contact portion 31, it is possible to weld the flow path member 3 to the metal support of the power generation cell 1 and form the gas flow hole 41 between the first contact portions 31 capable of supplying gas to the power generation cell 1.
[0047] The fuel cell stack (fuel cell) 100 is such that the length d1 of the first contact portion 31 in the direction intersecting the gas flow direction is less than or equal to the length d2 of the gas flow hole 41 in the direction intersecting the gas flow direction. Thereby, the gas flow rate of the gas supplied from the gas flow paths 4 and 5 to the power generation cell 1 can be increased.
[0048] Note that, as in this embodiment, it is preferable that the joint 34 is provided on the interconnector 2 side, but it is not necessarily limited to this. For example, the joint 34 may include an interconnector side joint extending in a direction intersecting the gas flow direction from the second contact portion 32 and a metal support side joint extending in a direction intersecting the gas flow direction from the first contact portion 31. Thereby, the flow path member 3 can be positioned more reliably. However, in this case, in order to make the area of the gas flow hole 41 as large as possible and ensure a large flow rate of the gas supplied from the gas flow path 4 to the fuel cell 1, the number of the metal support side joints is preferably less than or equal to the number of the interconnector side joints. Further, in this case, preferably, the interconnector side joints are provided at least at both ends of the flow path member 3 in the gas flow direction. Thereby, the flow path member 3 can be positioned reliably. Furthermore, in this case, preferably, the metal support side joints are provided at least at the central portion of the flow path member 3 in the gas flow direction. Thereby, the flow path member 3 can be positioned more reliably.
[0049] Also, as in this embodiment, each flow path member 3 preferably includes the joint 34, but it is not necessarily limited to this, and the joint 34 may not be provided. Even in this case, since the flow path member 3 extends along the gas flow direction, the current conduction path in the stacking direction of the fuel cell 1 can be increased, and since the gas flow holes 41 and 51 are formed in the entire region in the gas flow direction, the gas flow rate to the fuel cell 1 can be increased. That is, since the current conduction path in the stacking direction of the fuel cell 1 and the gas flow rate to the fuel cell 1 can be increased, the power generation efficiency of the fuel cell stack 100 is improved.
[0050] In addition, in the present embodiment, the flow path member 3 is configured as a Z-shaped member, but it is not necessarily limited to this. The flow path member 3 only needs to have a first contact portion 31 that contacts the metal support of the power generation cell 1, a second contact portion 32 that contacts the interconnector 2, and a connecting portion 33 that connects the first contact portion 31 and the second contact portion 32. The flow path member 3 may be configured as, for example, an S-shaped member with the left and right of the flow path member 3 of the present embodiment reversed.
[0051] Also, as in the present embodiment, it is preferable to provide metal supports on both sides of the power generation cell 1, but it is not necessarily limited to this, and a configuration in which a metal support is provided only on one surface of the power generation cell 1 may also be acceptable.
[0052] In addition, in the present embodiment, the first contact portion 31 of the fuel electrode side flow path member 3A is welded to the metal support, the second contact portion 32 is welded to the interconnector 2, the first contact portion 31 of the air electrode side flow path member 3B is welded to the metal support, and the second contact portion 32 is diffusion-bonded to the interconnector 2 of the adjacent power generation unit 10, but it is not necessarily limited to this. As long as the flow path member 3 can be brought into contact with the metal support of the power generation cell 1 and the interconnector 2, the bonding method may be arbitrarily selected.
[0053] Also, as in the present embodiment, it is preferable that the length d1 in the direction intersecting the gas flow direction of the first contact portion 31 is less than or equal to the length d2 in the direction intersecting the gas flow direction of the gas flow hole 41, but it is not necessarily limited to this. That is, even if the length in the direction intersecting the gas flow direction of the first contact portion 31 is greater than the length in the direction intersecting the gas flow direction of the gas flow hole 41, the gas flow rate to the power generation cell 1 can be made larger than before.
[0054] [Second Embodiment] Referring to FIGS. 10 and 11, the fuel cell stack (fuel cell) 100 of the second embodiment will be described. Note that the same reference numerals are given to the same elements as in the first embodiment, and the description thereof will be omitted.
[0055] FIG. 10 is a top view of the power generation unit 10 in the fuel cell stack (fuel cell) 100 according to the second embodiment, and FIG. 11 is (a) a cross-sectional view taken along line A-A of FIG. 10 and (b) a cross-sectional view taken along line B-B of FIG. 10. In this modification, the point that the flow path member 3 is offset at the central portion is different from the first embodiment.
[0056] As shown in FIGS. 10 and 11, in the present embodiment, the flow path member 3 includes a first flow path member 30A, a second flow path member 30B, and a third flow path member 30C. The first flow path member 30A extends from one end to the other end of the power generation unit 10 along the gas flow direction. The second flow path member 30B extends from one end to the central portion of the power generation unit 10 along the gas flow direction. The third flow path member 30C is provided at a position offset from the second flow path member 30B and extends from the central portion to the multi-end of the power generation unit 10.
[0057] Further, the first flow path member 30A, the second flow path member 30B, and the third flow path member 30C are alternately arranged in a direction intersecting the gas flow direction. Thereby, a first gas flow path 40A extending from one end to the multi-end of the power generation unit 10, a second gas flow path 40B extending from one end to the central portion of the power generation unit 10, and a third gas flow path 40C extending from the central portion to the multi-end of the power generation unit 10 and offset from the second gas flow path 40B are formed. The fuel gas (air on the air electrode side) passing through the first gas flow path 40A flows from one end to the multi-end of the power generation unit 10. On the other hand, the fuel gas (air on the air electrode side) passing through the second gas flow path 40B flows from one end to the central portion of the power generation unit 10 and is divided into the first gas flow path 40A and the third gas flow path 40C at the central portion. As a result, the gas flow field is disturbed, so that the fuel is homogenized and the power generation efficiency is improved.
[0058] [Third Embodiment] Referring to FIGS. 12 and 13, the fuel cell stack (fuel cell) 100 of the third embodiment will be described. Note that the same reference numerals are given to the same elements as in the other embodiments, and the description thereof is omitted.
[0059] FIG. 12 is a top view of the power generation unit 10 in the fuel cell stack (fuel cell) 100 according to the third embodiment, and FIG. 13 is (a) a cross-sectional view taken along line A-A of FIG. 12 and (b) a cross-sectional view taken along line B-B of FIG. 12. In this modification, similar to the second embodiment, the flow path member 3 is offset at the central portion, but the offset method is different from that of the second embodiment.
[0060] As shown in FIGS. 12 and 13, in the present embodiment, all the flow path members 3 other than both ends in the width direction of the power generation unit 10 (hereinafter referred to as both ends of the power generation unit 10) include a second flow path member 30B extending from one end to the central portion of the power generation unit 10 along the gas flow direction, and a third flow path member 30C provided at a position offset from the second flow path member 30B and extending from the central portion to the other end of the power generation unit 10. As a result, a plurality of second gas flow paths 40B extending from one end to the central portion of the power generation unit 10 and a plurality of third gas flow paths 40C offset from the second gas flow paths 40B and extending from the central portion to the other end of the power generation unit 10 are formed. Therefore, the fuel gas (air on the air electrode side) passing through the second gas flow path 40B flows from one end to the central portion of the power generation unit 10 and is branched into all the third gas flow paths 40C in the power generation unit 10 at the central portion. As a result, the gas flow field is disturbed, so that the fuel is homogenized and the power generation efficiency is improved.
[0061] Although the embodiments of the present invention have been described above, the above embodiments merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.
[0062] Each of the above-described embodiments has been described as an independent embodiment, but they may be combined as appropriate.
Description of Reference Numerals
[0063] 1, power generation cell; 2, interconnector; 3, flow path member; 31, first contact portion; 32, second contact portion; 33, connecting portion; 4, gas flow path; 41, gas circulation hole; 10, power generation unit; 100, fuel cell stack (fuel cell)
Claims
1. A fuel cell in which a plurality of power generation cells are stacked, between each power generation cell, there are provided an interconnector provided separately from the power generation cell, and a plurality of flow path members arranged in parallel between the interconnector and the power generation cell, the interconnector and the flow path member form a gas flow path through which the gas supplied to the power generation cell flows, the power generation cell includes a porous metal support on at least one surface, the flow path member has a first contact portion that contacts the metal support and extends along the gas flow direction, a second contact portion that contacts the interconnector and extends along the gas flow direction, and a connecting portion that connects the first contact portion and the second contact portion, by providing the first contact portion so as to be separated from the first contact portion of the adjacent flow path member, a gas circulation hole for supplying the gas from the gas flow path to the power generation cell is formed between the first contact portion of the flow path member and the first contact portion of the adjacent flow path member, Fuel cell.
2. The fuel cell according to claim 1, the flow path member includes a joint that connects to an adjacent flow path member intersecting the gas flow direction, Fuel cell.
3. The fuel cell according to claim 2, each flow path member includes a plurality of the joints respectively, Fuel cell.
4. The fuel cell according to claim 2, the joint extends in a direction intersecting the gas flow direction from the second contact portion, Fuel cell.
5. The fuel cell according to claim 2, the joint includes an interconnector side joint extending in a direction intersecting the gas flow direction from the second contact portion, and a metal support side joint extending in a direction intersecting the gas flow direction from the first contact portion, Fuel cell.
6. The fuel cell according to claim 5, the number of the metal support side joints is less than or equal to the number of the interconnector side joints, Fuel cell.
7. The fuel cell according to claim 5, the interconnector side joint is provided at least at both ends of the flow path member in the gas flow direction, Fuel cell.
8. The fuel cell according to claim 5, the metal support side joint is provided at least at the central portion of the flow path member in the gas flow direction, Fuel cell.
9. The fuel cell according to claim 2, The length of the joint in a direction intersecting the gas flow direction of the joint is longer than the length of the first contact portion in a direction intersecting the gas flow direction of the first contact portion. Fuel cell.
10. The fuel cell according to claim 1, The length of the first contact portion in a direction intersecting the gas flow direction is equal to or less than the length of the gas flow hole in a direction intersecting the gas flow direction. Fuel cell.
11. A method for manufacturing a fuel cell according to claim 1, A step of joining the first contact portion of the flow path member to the metal support of the power generation cell, A step of joining the second contact portion of the flow path member to the interconnector, A step of laminating the power generation cells to which the flow path member is joined, and When joining the flow path member to the interconnector, the angle formed by the second contact portion and the connecting portion is an obtuse angle. Method for manufacturing a fuel cell.
Citation Information
Patent Citations
Fuel cell stack
JP2013093184A