Electrochemical Cell Stack

Abstract

To improve the power generation efficiency by making the flow of fuel gas and oxidant gas uniform.SOLUTION: In an electrochemical cell stack 10, a plate-shaped electrochemical cell 11 is laminated. The electrochemical cell 11 generates electricity by the electrochemical reaction between fuel gas and oxidant gas. A fuel gas inlet 13 is located on one of first outer surfaces S1 in the stacking direction of the electrochemical cell 11. A fuel gas outlet 14 is located on a second outer surface S2 behind the first outer surface S1. One of oxidant gas inlets 15 of the first outer surface S1 and the second outer surface S2 is located, and an oxidant gas outlet 16 is located on the other side.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to electrochemical cell stacks. [Background technology]

[0002] Fuel cells are known that generate electricity through an electrochemical reaction between a fuel gas and an oxidant gas. Fuel cells are assembled into an electrochemical cell stack in which electrochemical cells, which are the smallest units for generating electricity, are stacked (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-225078 Summary of the Invention [Problem to be solved by the invention]

[0004] To improve power generation efficiency, it is desirable to make the flows of fuel gas and oxidant gas uniform among the stacked electrochemical cells, but achieving uniform flows has been difficult.

[0005] Therefore, an object of the present disclosure, made in consideration of the above-described problems of the conventional technology, is to provide an electrochemical cell stack that uniformizes the flow of fuel gas and oxidant gas and improves power generation efficiency. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, an electrochemical cell stack according to a first aspect comprises: An electrochemical cell stack in which plate-shaped electrochemical cells that generate electricity by an electrochemical reaction between a fuel gas and an oxidant gas are stacked, A fuel gas inlet is located on one first outer surface in the stacking direction of the electrochemical cell, and a fuel gas outlet is located on a second outer surface behind the first outer surface. An oxidant gas inlet is located on one of the first outer surface and the second outer surface, and an oxidant gas outlet is located on the other. [Effects of the Invention]

[0007] According to the electrochemical cell stack of the present disclosure configured as described above, the flows of the fuel gas and the oxidant gas can be made uniform, thereby improving the power generation efficiency. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view of an electrochemical cell stack according to a first embodiment. [Figure 2] FIG. 2 is a top view of the electrochemical cell stack of FIG. 1. [Figure 3] FIG. 2 is a cross-sectional view of the electrochemical cell of FIG. 1 taken along the thickness direction. [Figure 4] FIG. 4 is a cross-sectional view of the electrochemical cell taken along line IV-IV in FIG. [Figure 5] FIG. 4 is a cross-sectional view of the electrochemical cell taken along line VV in FIG. [Figure 6] FIG. 1 is a conceptual diagram illustrating gas flow paths in an electrochemical cell stack in which the gas inlet and outlet are located on the same surface. [Figure 7] FIG. 10 is a perspective view of an electrochemical cell stack according to a second embodiment. [Figure 8] FIG. 8 is a top view of the electrochemical cell stack of FIG. 7. [Figure 9] FIG. 10 is a perspective view of an electrochemical cell stack according to a third embodiment. [Figure 10] FIG. 10 is a top view of the electrochemical cell stack of FIG. 9. [Figure 11] FIG. 10 is a perspective view of an electrochemical cell stack according to a fourth embodiment. [Figure 12] FIG. 12 is a top view of the electrochemical cell stack of FIG. [Figure 13] FIG. 12 is a cross-sectional view of the inlet-side electrochemical cell of FIG. 11 taken along the thickness direction. [Figure 14]FIG. 14 is a cross-sectional view of the inlet side electrochemical cell taken along line XIV-XIV in FIG. 13. [Figure 15] FIG. 14 is a cross-sectional view of the inlet-side electrochemical cell taken along line XV-XV in FIG. 13. [Figure 16] FIG. 12 is a cross-sectional view of the outlet side electrochemical cell of FIG. 11 taken along the thickness direction. [Figure 17] FIG. 17 is a cross-sectional view of the outlet side electrochemical cell taken along line XVII-XVII in FIG. 16. [Figure 18] FIG. 17 is a cross-sectional view of the outlet side electrochemical cell taken along line XVIII-XVIII in FIG. 16. [Figure 19] FIG. 12 is a conceptual diagram for explaining the flow of fuel gas within the electrochemical cell stack of FIG. [Figure 20] FIG. 12 is a conceptual diagram for explaining the flow of oxidant gas within the electrochemical cell stack of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of an electrochemical cell stack to which the present disclosure is applied will be described with reference to the drawings.

[0010] 1, an electrochemical cell stack 10 according to the first embodiment of the present disclosure is formed by stacking a plurality of plate-shaped electrochemical cells 11. The stacked electrochemical cells 11 may be sandwiched between a first end plate 12a and a second end plate 12b from both ends in the stacking direction.

[0011] The shape of the electrochemical cell stack 10 as viewed from the stacking direction may be any shape, for example, rectangular, hexagonal, circular, etc. In the first embodiment, the shape of the electrochemical cell stack 10 as viewed from the stacking direction is rectangular.

[0012] A fuel gas inlet 13 is located on one first outer surface S1 in the stacking direction. A fuel gas outlet 14 is located on a second outer surface S2 on the back side of the first outer surface S1 in the stacking direction. In the electrochemical cell stack 10, an oxidizer gas inlet 15 is located on one of the first outer surface S1 and the second outer surface S2, and an oxidizer gas outlet 16 is located on the other. In the first embodiment, the oxidizer gas inlet 15 is located on the first outer surface S1, and the oxidizer gas outlet 16 is located on the second outer surface S2.

[0013] 2, the fuel gas inlet 13 and the fuel gas outlet 14 may be located at either end of the electrochemical cell stack 10 in any direction perpendicular to the stacking direction (the vertical direction in FIG. 2). The oxidant gas inlet 15 and the oxidant gas outlet 16 may be located at either end of the electrochemical cell stack 10 in any direction perpendicular to the stacking direction (the vertical direction in FIG. 2).

[0014] In a configuration in which the outer edge of the first outer surface S1 includes two parallel sides, the fuel gas inlet 13 and the fuel gas outlet 14 may be located near the two sides, respectively. The oxidant gas inlet 15 and the oxidant gas outlet 16 may be located near the two sides, respectively, when viewed from the stacking direction.

[0015] When viewed from the stacking direction, the oxidant gas inlet 15 may be located closer to the fuel gas inlet 13 than the center of the line segment connecting the fuel gas inlet 13 and the fuel gas outlet 14. In this specification, the line segment connecting the inlet and the outlet may be the line segment connecting the centers of the inlet and the outlet. When viewed from the stacking direction, the oxidant gas outlet 16 may be located closer to the fuel gas outlet 14 than the center of the line segment connecting the fuel gas inlet 13 and the fuel gas outlet 14.

[0016] When viewed from the stacking direction, a line segment connecting the fuel gas inlet 13 and the fuel gas outlet 14 and a line segment connecting the oxidant gas inlet 15 and the oxidant gas outlet 16 may intersect. For example, when viewed from the stacking direction, the line segment connecting the fuel gas inlet 13 and the fuel gas outlet 14 may be inclined with respect to one side near the fuel gas inlet 13 at the outer edge of the first outer surface S1. When viewed from the stacking direction, the line segment connecting the oxidant gas inlet 15 and the oxidant gas outlet 16 may be inclined with respect to one side near the oxidant gas inlet 15 at the outer edge of the first outer surface S1.

[0017] The electrochemical cell stack 10 may be installed as part of a battery device so that the stacking direction is parallel to the vertical direction on the ground surface. In a configuration in which the stacking direction is parallel to the vertical direction, it is further preferable that the first surface is installed facing vertically downward. Alternatively, the electrochemical cell stack 10 may be installed as part of a battery device so that the stacking direction is horizontal on the ground surface. In a configuration in which the stacking direction is horizontal, it may further be installed so that the fuel gas outlet 14 and the oxidant gas outlet 16 are located higher than the fuel gas inlet 13 and the oxidant gas inlet 15.

[0018] 3, in the electrochemical cell 11, a plate-shaped electrolyte membrane 17 may be sandwiched between two interconnectors 20 from both plate surface sides via a fuel electrode 18 and an air electrode 19. The space between the two interconnectors 20 may be sealed by a frame 21.

[0019] The electrochemical cell 11 may be a solid oxide fuel cell, a polymer electrolyte fuel cell, a phosphoric acid fuel cell, or a molten carbonate fuel cell. The fuel electrode 18 and the air electrode 19 may be made of materials suitable for each system and may have a structure suitable for each system.

[0020] The interconnector 20 may be, for example, a metal plate having the same shape as the plate surface of the electrochemical cell 11. The interconnector 20 may be provided with a plurality of ridges 22 parallel to the plate surface. The interconnector 20 may be in contact with the anode 18 via the ridges 22. The interconnector 20 may be in contact with the cathode 19 via the ridges 22.

[0021] The frame 21 may be formed from an electrically insulating material. The frame 21 may be in the shape of a frame along the outer edge of the plate surface of the interconnector 20. The frame 21 may be in close contact with the plate surface near the outer edge of the two interconnectors 20, with the surfaces of the two interconnectors 20 on which the ridge portions 22 are provided facing each other.

[0022] 4 and 5, the frame 21 may be formed with a first fuel gas passage hole 23, a second fuel gas passage hole 24, a first oxidant gas passage hole 25, and a second oxidant gas passage hole 26 together with the interconnector 20. The first fuel gas passage hole 23, the second fuel gas passage hole 24, the first oxidant gas passage hole 25, and the second oxidant gas passage hole 26 may penetrate the frame 21 in the thickness direction, in other words, parallel to the axial direction of the frame.

[0023] As shown in Fig. 3, a fuel gas chamber FR is defined on the fuel electrode 18 side by the electrolyte membrane 17, the interconnector 20, and the frame 21. An oxidant gas chamber OR is defined on the air electrode 19 side by the electrolyte membrane 17, the interconnector 20, and the frame 21. As shown in Fig. 4, a hole may be formed in a part of the frame 21, thereby connecting the fuel gas chamber FR to the first fuel gas passing hole 23 and the second fuel gas passing hole 24. As shown in Fig. 5, a hole may be formed in a part of the frame 21, thereby connecting the oxidant gas chamber OR to the first oxidant gas passing hole 25 and the second oxidant gas passing hole 26.

[0024] The electrochemical cells 11 may be stacked such that the first fuel gas passage holes 23 of each electrochemical cell 11 are continuous, the second fuel gas passage holes 24 of each electrochemical cell 11 are continuous, the first oxidant gas passage holes 25 of each electrochemical cell 11 are continuous, and the second oxidant gas passage holes 26 of each electrochemical cell 11 are continuous. As shown in FIG. 1 , by stacking the electrochemical cells 11 in this manner, the first fuel gas passage holes 23 of all the electrochemical cells 11 may form a fuel gas inlet hole 27 parallel to the stacking direction. The first oxidant gas passage holes 25 of all the electrochemical cells 11 may form an oxidant gas inlet hole 28 parallel to the stacking direction. The second fuel gas passage holes 24 of all the electrochemical cells 11 may form a fuel gas outlet hole 29 parallel to the stacking direction. The second oxidant gas passage holes 26 of all the electrochemical cells 11 may form an oxidant gas outlet hole 30 parallel to the stacking direction.

[0025] The first end plate 12a may be located on the first outer surface S1 side. The second end plate 12b may be located on the second outer surface S2 side. The first end plate 12a may have a fuel gas inlet 13 formed therein, which is a hole, and one of the oxidant gas inlet 15 and the oxidant gas outlet 16. The second end plate 12b may have a fuel gas outlet 14 formed therein, which is a hole, and the other of the oxidant gas inlet 15 and the oxidant gas outlet 16. As described above, in the first embodiment, the oxidant gas inlet 15 is formed in the first end plate 12a, and the oxidant gas outlet 16 is formed in the second end plate 12b.

[0026] The fuel gas inlet 13 and the fuel gas supply hole 27 may be continuous. The fuel gas outlet 14 and the fuel gas discharge hole 29 may be continuous. The oxidant gas inlet 15 and the oxidant gas supply hole 28 may be continuous. The oxidant gas outlet 16 and the oxidant gas discharge hole 30 may be continuous.

[0027] The fuel gas supplied from the fuel gas inlet 13 may flow into each fuel gas chamber FR through the fuel gas supply holes 27. The oxidant gas supplied from the oxidant gas inlet 15 may flow into each oxidant gas chamber OR through the oxidant gas supply holes 28. Each electrochemical cell 11 generates electricity through an electrochemical reaction between the fuel gas supplied to the fuel gas chamber FR of each electrochemical cell 11 and the oxidant gas supplied to the oxidant gas chamber OR of each electrochemical cell 11.

[0028] In the electrochemical cell stack 10 of the first embodiment configured as described above, the fuel gas inlet 13 is located on the first outer surface S1, the fuel gas outlet 14 is located on the second outer surface S2, the oxidizer gas inlet 15 is located on one of the first outer surface S1 and the second outer surface S2, and the oxidizer gas outlet 16 is located on the other. For example, in a typical electrochemical cell stack, it is conceivable that the fuel gas and oxidizer gas inlets and outlets are located on the same surface. In such a structure, as shown in FIG. 6 , the fuel gas and oxidizer gas flow from the inlet IN in one direction in the stacking direction, flow through each electrochemical cell 11′ in a direction perpendicular to the stacking direction, turn around in the opposite direction to the stacking direction, and are discharged from the outlet OUT. In contrast, in the electrochemical cell stack 10 of the first embodiment, the fuel gas and oxidizer gas each flow in one direction in the stacking direction, allowing the fuel gas and oxidizer gas to be efficiently distributed throughout the stack, thereby improving power generation efficiency.

[0029] Furthermore, in the electrochemical cell stack 10 of the first embodiment, the fuel gas inlet 13 and the oxidizer gas inlet 15 are located on the first outer surface S1, and the fuel gas outlet 14 and the oxidizer gas outlet 16 are located on the second outer surface S2. With this configuration, when the electrochemical cell stack 10 is arranged so that the stacking direction is parallel to the vertical direction and the first outer surface S1 is located vertically downward, the fuel gas and the oxidizer gas flow in one direction, vertically from downward to upward. Therefore, the electrochemical cell stack 10 can reduce pressure loss between the multiple electrochemical cells 11. As a result, the electrochemical cell stack 10 can reduce the difference in the amount of gas reaching the multiple stacked electrochemical cells 11. In particular, when the number of stacked electrochemical cells is large, in a typical electrochemical cell stack, both the fuel gas and the oxidizer gas have difficulty reaching the electrochemical cells 11' that are far from the inlet IN and outlet OUT. Therefore, in a typical electrochemical cell stack, new gas is not introduced and old gas remains, resulting in variations in performance and lifespan. On the other hand, the electrochemical cell stack 10 having the above-described configuration can reduce the difference in the amount of gas reaching the multiple electrochemical cells 11, thereby reducing the occurrence of performance variations and lifespan variations and improving power generation efficiency.

[0030] Furthermore, in the electrochemical cell stack 10 of the first embodiment, the fuel gas inlet 13 and outlet 14 are located at both ends of the electrochemical cell stack 10 in any one direction perpendicular to the stacking direction, and the oxidant gas inlet 15 and outlet 16 are located at both ends of the electrochemical cell stack 10 in any one direction perpendicular to the stacking direction. With this configuration, the electrochemical cell stack 10 can distribute the fuel gas throughout the fuel gas chamber FR and the oxidant gas throughout the oxidant gas chamber in each electrochemical cell 11, thereby improving power generation efficiency.

[0031] Furthermore, in the electrochemical cell stack 10 of the first embodiment, the oxidant gas inlet 15 is located closer to the fuel gas inlet 13 than the center of the line segment connecting the fuel gas inlet 13 and outlet 14, as viewed in the stacking direction. This allows the high-temperature fuel gas and oxidant gas to flow a longer distance from below to above in the electrochemical cell stack 10, thereby further reducing pressure loss between the multiple electrochemical cells 11 and further improving power generation efficiency.

[0032] Furthermore, in the electrochemical cell stack 10 of the first embodiment, when viewed from the stacking direction, the fuel gas inlet 13 and the oxidant gas inlet 15 are located near one of two parallel sides of the electrochemical cell stack 10, and the fuel gas outlet 14 and the oxidant gas outlet 16 are located near the other side. With this configuration, when the electrochemical cell stack 10 is arranged so that the stacking direction is parallel to the horizontal direction and the side near the fuel gas inlet 13 and the oxidant gas inlet 16 is located vertically downward, the fuel gas and the oxidant gas flow in one direction, from vertically downward to vertically upward. Therefore, the electrochemical cell stack 10 can reduce pressure loss between the multiple electrochemical cells 11.

[0033] Furthermore, in the electrochemical cell stack 10 of the first embodiment, when viewed from the stacking direction, a line segment connecting the fuel gas inlet 13 and outlet 14 intersects with a line segment connecting the oxidizer gas inlet 15 and outlet 16. With this configuration, the electrochemical cell stack 10 can distribute the fuel gas throughout the fuel gas chamber FR and the oxidizer gas throughout the oxidizer gas chamber, thereby further improving power generation efficiency.

[0034] Next, an electrochemical cell stack according to a second embodiment of the present disclosure will be described. In the second embodiment, the positions of the fuel gas inlet and outlet and the oxidant gas inlet and outlet are different from those of the first embodiment. The second embodiment will be described below, focusing on the differences from the first embodiment. Note that parts having the same configuration as those in the first embodiment are given the same reference numerals.

[0035] 7, in the electrochemical cell stack 100 of the second embodiment, similar to the first embodiment, a fuel gas inlet 130 is located on one first outer surface S1 in the stacking direction. Also, a fuel gas outlet 14 is located on the second outer surface S2. In the second embodiment, unlike the first embodiment, an oxidant gas outlet 160 is located on the first outer surface S1, and an oxidant gas inlet 150 is located on the second outer surface S2.

[0036] 8, the fuel gas inlet 130 and the fuel gas outlet 14 may be located at both ends of the electrochemical cell stack 10 in any direction perpendicular to the stacking direction (the vertical direction in FIG. 8), similar to the first embodiment. Similarly to the first embodiment, the oxidant gas inlet 150 and the oxidant gas outlet 160 may be located at both ends of the electrochemical cell stack 100 in any direction perpendicular to the stacking direction (the vertical direction in FIG. 8).

[0037] Similar to the first embodiment, the oxidant gas inlet 150 may be located closer to the fuel gas inlet 130 than the center of a line segment connecting the fuel gas inlet 130 and the fuel gas outlet 14 when viewed from the stacking direction. Similar to the first embodiment, the oxidant gas outlet 160 may be located closer to the fuel gas outlet 14 than the center of a line segment connecting the fuel gas inlet 130 and the fuel gas outlet 14 when viewed from the stacking direction.

[0038] Unlike the first embodiment, when viewed from the stacking direction, the line segment connecting the fuel gas inlet 130 and the fuel gas outlet 14 does not intersect with the line segment connecting the oxidant gas inlet 150 and the oxidant gas outlet 160. In other words, when viewed from the stacking direction, an extension of the line segment connecting the fuel gas inlet 130 and the fuel gas outlet 14 intersects or is parallel to an extension of the line segment connecting the oxidant gas inlet 150 and the oxidant gas outlet 160.

[0039] The electrochemical cell stack 100 may be installed as part of a battery device with the stacking direction horizontal to the ground. In a configuration where the stacking direction is horizontal, the fuel gas outlet 14 and the oxidant gas outlet 160 may be installed so as to be located higher than the fuel gas inlet 130 and the oxidant gas inlet 150.

[0040] In the electrochemical cell stack 100 of the second embodiment configured as described above, similar to the first embodiment, the fuel gas inlet 130 is located on the first outer surface S1, the fuel gas outlet 14 is located on the second outer surface S2, and the oxidant gas inlet 150 is located on one of the first outer surface S1 and the second outer surface S2, and the oxidant gas outlet 160 is located on the other. Therefore, similar to the first embodiment, the electrochemical cell stack 100 can efficiently distribute the fuel gas and oxidant gas throughout, thereby improving power generation efficiency.

[0041] Furthermore, in the electrochemical cell stack 100 of the second embodiment, similar to the first embodiment, the fuel gas inlet 130 and outlet 14 are located at both ends of the electrochemical cell stack 100 in any one direction perpendicular to the stacking direction, and the oxidant gas inlet 150 and outlet 160 are located at both ends of the electrochemical cell stack 10 in any one direction perpendicular to the stacking direction. Therefore, the electrochemical cell stack 100 can distribute the fuel gas throughout the fuel gas chamber FR and the oxidant gas throughout the oxidant gas chamber in each electrochemical cell 11, thereby improving power generation efficiency.

[0042] Furthermore, in the electrochemical cell stack 100 of the second embodiment, the oxidant gas inlet 150 is located closer to the fuel gas inlet 130 than the center of the line segment connecting the fuel gas inlet 130 and the fuel gas outlet 14, as viewed from the stacking direction, and an extension of the line segment connecting the fuel gas inlet 130 and the fuel gas outlet 14 intersects or is parallel to an extension of the line segment connecting the oxidant gas inlet 150 and the oxidant gas outlet 160, as viewed from the stacking direction. With this configuration, the electrochemical cell stack 100 can separate the fuel gas inlet 130 and the fuel gas outlet 14 from the oxidant gas inlet 150 and the oxidant gas outlet 160. Therefore, the electrochemical cell stack 100 improves design flexibility to avoid interference between pipes separately connecting the fuel gas inlet 130 and the fuel gas outlet 14 to the oxidant gas inlet 150 and the oxidant gas outlet 160.

[0043] Next, an electrochemical cell stack according to a third embodiment of the present disclosure will be described. In the third embodiment, the positions of the fuel gas inlet and outlet and the oxidant gas inlet and outlet are different from those of the first embodiment. The third embodiment will be described below, focusing on the differences from the first embodiment. Note that parts having the same configuration as those in the first embodiment are given the same reference numerals.

[0044] 9, in an electrochemical cell stack 101 of the third embodiment, a fuel gas inlet 131 is located on one first outer surface S1 in the stacking direction, similar to the first embodiment. Also, a fuel gas outlet 141 is located on the second outer surface S2. In the third embodiment, an oxidant gas inlet 151 is located on the first outer surface S1, and an oxidant gas outlet 161 is located on the second outer surface S2, similar to the first embodiment.

[0045] 10, the fuel gas inlet 131 and the fuel gas outlet 141 may be located at both ends of the electrochemical cell stack 101 in any direction perpendicular to the stacking direction (the up-down direction in FIG. 10), similar to the first embodiment. The oxidizer gas inlet 151 and the oxidizer gas outlet 161 may be located at both ends of the electrochemical cell stack 101 in any direction perpendicular to the stacking direction (the left-right direction in FIG. 10), similar to the first embodiment.

[0046] When viewed from the stacking direction, a line segment connecting the fuel gas inlet 131 and the fuel gas outlet 141 and a line segment connecting the oxidant gas inlet 151 and the oxidant gas outlet 161 may intersect at an intersection IP1. In the third embodiment, unlike the first embodiment, when viewed from the stacking direction, the angle between the line segment connecting the fuel gas inlet 131 and the intersection IP1 and the line segment connecting the oxidant gas inlet 151 and the intersection IP1 may be greater than 45° and less than 135°. More specifically, this angle may be 90°. Furthermore, the line segment connecting the fuel gas inlet 131 and the fuel gas outlet 141 may be perpendicular to a side near the fuel gas inlet 131 at the outer edge of the first outer surface S1. Furthermore, the line segment connecting the oxidant gas inlet 151 and the oxidant gas outlet 161 may be perpendicular to a side near the oxidant gas inlet 151 at the outer edge of the first outer surface S1.

[0047] In the electrochemical cell stack 101 of the third embodiment configured as described above, similar to the first embodiment, a fuel gas inlet 131 is located on the first outer surface S1, a fuel gas outlet 141 is located on the second outer surface S2, an oxidant gas inlet 151 is located on one of the first outer surface S1 and the second outer surface S2, and an oxidant gas outlet 161 is located on the other. Therefore, similar to the first embodiment, the electrochemical cell stack 101 can efficiently distribute the fuel gas and oxidant gas throughout, thereby improving power generation efficiency.

[0048] Furthermore, in the electrochemical cell stack 101 of the third embodiment, similar to the first embodiment, the fuel gas inlet 131 and outlet 141 are located at both ends of the electrochemical cell stack 101 in any one direction perpendicular to the stacking direction, and the oxidant gas inlet 151 and outlet 161 are located at both ends of the electrochemical cell stack 101 in any one direction perpendicular to the stacking direction. Therefore, the electrochemical cell stack 101 can distribute the fuel gas throughout the fuel gas chamber FR and the oxidant gas throughout the oxidant gas chamber in each electrochemical cell 11, thereby improving power generation efficiency.

[0049] Furthermore, in the electrochemical cell stack 101 of the third embodiment, the angle between the line segment connecting the fuel gas inlet 131 and the intersection point IP and the line segment connecting the oxidant gas inlet 151 and the intersection point IP is greater than 45° and less than 135° when viewed from the stacking direction. With this configuration, the electrochemical cell stack 101 can separate the fuel gas inlet 131 and the fuel gas outlet 141, and the oxidant gas inlet 151 and the oxidant gas outlet 161 from each other. Therefore, the electrochemical cell stack 101 improves the degree of freedom in design to avoid interference between pipes separately connected to the fuel gas inlet 131 and the fuel gas outlet 141, and the oxidant gas inlet 151 and the oxidant gas outlet 161.

[0050] Next, an electrochemical cell stack according to a fourth embodiment of the present disclosure will be described. In the fourth embodiment, the positions of the fuel gas inlet and outlet and the oxidant gas inlet and outlet, and the structure of the electrochemical cell are different from those of the first embodiment. The fourth embodiment will be described below, focusing on the differences from the first embodiment. Note that parts having the same configuration as those in the first embodiment are given the same reference numerals.

[0051] 11 , an electrochemical cell stack 102 of the fourth embodiment may include stacked electrochemical cells 112 and a first end plate 122a and a second end plate 122b that sandwich the stacked electrochemical cells 112 from both ends in the stacking direction, similar to the first embodiment. In the electrochemical cell stack 102, a fuel gas inlet 132 is located on one first outer surface S1 in the stacking direction, similar to the first embodiment. A fuel gas outlet 142 is located on the second outer surface S2. In the fourth embodiment, an oxidant gas inlet 152 is located on the first outer surface S1, and an oxidant gas outlet 162 is located on the second outer surface S2, similar to the first embodiment.

[0052] In the fourth embodiment, unlike the first embodiment, in the electrochemical cell stack 102, in at least one of a pair of a fuel gas inlet 132 and a fuel gas outlet 142 and a pair of an oxidizer gas inlet 152 and an oxidizer gas outlet 162, the flow path of at least one electrochemical cell 112 located on the inlet side in the stacking direction is connected to the inlet. Furthermore, the flow paths of all the stacked electrochemical cells 112 are connected to the internal flow path at a position different from the inlet when viewed from the stacking direction. Of all the electrochemical cells 112, the flow paths of the electrochemical cells 112 other than the electrochemical cell 112 connected to the inlet are connected to the outlet at a position different from the internal flow path when viewed from the stacking direction. This structure will be described in detail below.

[0053] 12, a set of a fuel gas inlet 132 and a fuel gas outlet 142 and an internal fuel gas flow path 312, which will be described later, may be located at both ends of the electrochemical cell stack 102 in any direction perpendicular to the stacking direction (the up-down direction in FIG. 12). A set of an oxidant gas inlet 152 and an oxidant gas outlet 162 and an internal oxidant gas flow path 322, which will be described later, may be located at both ends of the electrochemical cell stack 102 in any direction perpendicular to the stacking direction (the left-right direction in FIG. 12).

[0054] When viewed from the stacking direction, a line segment connecting the first center point C1 of the fuel gas inlet 132 and the fuel gas outlet 142 to the internal fuel gas flow channel 312 and a line segment connecting the second center point C2 of the oxidizer gas inlet 152 and the oxidizer gas outlet 162 to the internal oxidizer gas flow channel 322 may intersect at an intersection IP2. In the fourth embodiment, unlike the first embodiment, when viewed from the stacking direction, the angle between the line segment connecting the first center point C1 and the intersection IP2 and the line segment connecting the second center point C2 and the intersection IP2 may be greater than 45° and less than 135°. More specifically, this angle may be 90°. Furthermore, the line segment connecting the first center point C1 and the internal fuel gas flow channel 312 may be perpendicular to one side of the outer edge of the first outer surface S1 near the fuel gas inlet 132. Furthermore, the line segment connecting the second center point C2 and the internal oxidant gas flow path 322 may be perpendicular to one side near the oxidant gas inlet 152 on the outer edge of the first outer surface S1.

[0055] 11, the electrochemical cells 112 include inlet electrochemical cells 112a and outlet electrochemical cells 112b. The number of the inlet electrochemical cells 112a and the outlet electrochemical cells 112b may be the same.

[0056] 13, in the inlet-side electrochemical cell 112a, similar to the first embodiment, a plate-shaped electrolyte membrane 17 may be sandwiched between two inlet-side interconnectors 202a from both plate surfaces via a fuel electrode 18 and an air electrode 19. The space between the two inlet-side interconnectors 202a may be sealed by an inlet-side frame 212a.

[0057] 14 and 15, unlike the first embodiment, the inlet side frame 212a may be formed with an inlet side interconnector 202a as well as first fuel gas passing holes 232, third fuel gas passing holes 332, first oxidant gas passing holes 252, and third oxidant gas passing holes 342. The first fuel gas passing holes 232, third fuel gas passing holes 332, first oxidant gas passing holes 252, and third oxidant gas passing holes 342 may penetrate the inlet side frame 212a in the thickness direction, in other words, parallel to the axial direction of the frame.

[0058] 14, holes may be formed in a portion of the inlet side frame 212a, thereby connecting the fuel gas chamber FR to the first fuel gas passing hole 232 and the third fuel gas passing hole 332. As shown in Fig. 15, holes may be formed in a portion of the inlet side frame 212a, thereby connecting the oxidizing gas chamber OR to the first oxidizing gas passing hole 252 and the third oxidizing gas passing hole 342.

[0059] 16, in the outlet-side electrochemical cell 112b, similar to the first embodiment, a plate-shaped electrolyte membrane 17 may be sandwiched between two outlet-side interconnectors 202b from both plate surfaces via a fuel electrode 18 and an air electrode 19. The space between the two outlet-side interconnectors 202b may be sealed by an outlet-side frame 212b.

[0060] 17 and 18, unlike the first embodiment, the outlet-side frame 212b may be formed with the outlet-side interconnector 202b as well as second fuel gas passing holes 242, third fuel gas passing holes 332, second oxidant gas passing holes 262, and third oxidant gas passing holes 342. The second fuel gas passing holes 242, third fuel gas passing holes 332, second oxidant gas passing holes 262, and third oxidant gas passing holes 342 may penetrate the outlet-side frame 212b in the thickness direction, in other words, parallel to the axial direction of the frame.

[0061] 17, holes may be formed in a portion of the outlet-side frame 212b, thereby connecting the fuel gas chamber FR to the second fuel gas passing hole 242 and the third fuel gas passing hole 332. As shown in Fig. 18, holes may be formed in a portion of the outlet-side frame 212b, thereby connecting the oxidizing gas chamber OR to the second oxidizing gas passing hole 262 and the third oxidizing gas passing hole 342.

[0062] The inlet side electrochemical cells 112a may be stacked so that the first fuel gas passage holes 232 of each inlet side electrochemical cell 112a are continuous, the third fuel gas passage holes 332 of each inlet side electrochemical cell 112a are continuous, the first oxidant gas passage holes 252 of each inlet side electrochemical cell 112a are continuous, and the third oxidant gas passage holes 342 of each inlet side electrochemical cell 112a are continuous.

[0063] The outlet side electrochemical cells 112b may be stacked so that the second fuel gas passage holes 242 of each outlet side electrochemical cell 112b are continuous, the third fuel gas passage holes 332 of each outlet side electrochemical cell 112b are continuous, the second oxidant gas passage holes 262 of each outlet side electrochemical cell 112b are continuous, and the third oxidant gas passage holes 342 of each outlet side electrochemical cell 112b are continuous.

[0064] The stacked plurality of inlet side electrochemical cells 112a and the stacked plurality of outlet side electrochemical cells 112b may be stacked so that the third fuel gas passing holes 332 of each inlet side electrochemical cell 112a and each outlet side electrochemical cell 112b are continuous, and so that the third fuel gas passing holes 332 of each inlet side electrochemical cell 112a and each outlet side electrochemical cell 112b are continuous.

[0065] 11, by stacking the inlet-side electrochemical cells 112a in this manner, the first fuel gas passage holes 232 of the inlet-side electrochemical cells 112a may form fuel gas supply holes 272 parallel to the stacking direction. With the above-described configuration, the fuel gas supply holes 272 are connected to the fuel gas chambers FR (flow paths of the electrochemical cells) of the inlet-side electrochemical cells 112a.

[0066] Furthermore, the first oxidant gas passage holes 252 of the inlet-side electrochemical cells 112a may form an oxidant gas supply hole 282 parallel to the stacking direction. With the above-described configuration, the oxidant gas supply hole 282 is connected to the oxidant gas chamber OR (flow path of the electrochemical cell) of each inlet-side electrochemical cell 112a.

[0067] Furthermore, the second fuel gas passage holes 242 of the outlet-side electrochemical cells 112b may form fuel gas discharge holes 292 parallel to the stacking direction. With the above-described configuration, the fuel gas discharge holes 292 are connected to the fuel gas chambers FR (flow paths of the electrochemical cells) of the outlet-side electrochemical cells 112b.

[0068] Furthermore, the second oxidant gas passage holes 262 of the outlet side electrochemical cells 112b may form an oxidant gas discharge hole 302 parallel to the stacking direction. With the above-described configuration, the oxidant gas discharge hole 302 is connected to the oxidant gas chamber OR (the flow path of the electrochemical cell) of each outlet side electrochemical cell 112b.

[0069] Furthermore, the third fuel gas passage holes 332 in all of the inlet-side electrochemical cells 112a and all of the outlet-side electrochemical cells 112b may form an internal fuel gas flow path 312 parallel to the stacking direction. With the above-described configuration, the internal fuel gas flow path 312 is connected to the fuel gas chambers FR (electrochemical cell flow paths) of each of the inlet-side electrochemical cells 112a and each of the outlet-side electrochemical cells 112b.

[0070] Furthermore, an internal oxidant gas flow path 322 parallel to the stacking direction may be formed by the third oxidant gas passage holes 342 of all the inlet electrochemical cells 112a and all the outlet electrochemical cells 112b. With the above-described configuration, the internal oxidant gas flow path 322 is connected to the oxidant gas chamber OR (flow path of the electrochemical cell) of each of the inlet electrochemical cells 112a and each of the outlet electrochemical cells 112b.

[0071] 11 , the first end plate 122a may be located on the first outer surface S1 side. The second end plate 122b may be located on the second outer surface S2 side. The first end plate 122a may have a fuel gas inlet 132 and an oxidant gas inlet 152 formed therein, each having a hole. The second end plate 122b may have a fuel gas outlet 142 and an oxidant gas outlet 162 formed therein.

[0072] The fuel gas inlet 132 and the fuel gas supply hole 272 may be continuous. Therefore, the fuel gas inlet 132 is connected to the fuel gas chamber FR (the flow path of the electrochemical cell) of the inlet-side electrochemical cell 112a via the fuel gas supply hole 272. The fuel gas outlet 142 and the fuel gas discharge hole 292 may be continuous. Therefore, the fuel gas outlet 142 is connected to the fuel gas chamber FR (the flow path of the electrochemical cell) of the outlet-side electrochemical cell 112b via the fuel gas discharge hole 292. The oxidizer gas inlet 152 and the oxidizer gas supply hole 282 may be continuous. Therefore, the oxidizer gas inlet 152 is connected to the oxidizer gas chamber OR (the flow path of the electrochemical cell) of the inlet-side electrochemical cell 112a via the oxidizer gas supply hole 282. The oxidizer gas outlet 162 and the oxidizer gas discharge hole 302 may be continuous. Therefore, the oxidant gas outlet 162 is connected via the oxidant gas discharge hole 302 to the oxidant gas chamber OR (the flow path of the electrochemical cell) of the outlet-side electrochemical cell 112b.

[0073] 19 , the fuel gas supplied from the fuel gas inlet 132 may flow into each fuel gas chamber FR of the inlet-side electrochemical cell 112a through the fuel gas supply holes 272. The fuel gas that has flowed into each fuel gas chamber FR may then flow into the internal fuel gas flow path 312 and into each fuel gas chamber FR of the outlet-side electrochemical cell 112b. The fuel gas that has flowed into each fuel gas chamber FR of the outlet-side electrochemical cell 112b may then be discharged from the electrochemical cell stack 102 through the fuel gas discharge holes 292 and the fuel gas outlet 142.

[0074] 20 , the oxidant gas supplied from the oxidant gas inlet 152 may flow into each oxidant gas chamber OR of the inlet-side electrochemical cell 112a through the oxidant gas supply holes 282. The fuel gas that has flowed into each oxidant gas chamber OR may flow into the oxidant gas internal flow path 322 and into each oxidant gas chamber OR of the outlet-side electrochemical cell 112b. The fuel gas that has flowed into each oxidant gas chamber OR of the outlet-side electrochemical cell 112b may be discharged from the electrochemical cell stack 102 through the oxidant gas discharge holes 3022 and the oxidant gas outlet 162.

[0075] In the electrochemical cell stack 102 of the fourth embodiment configured as described above, similar to the first embodiment, the fuel gas inlet 132 is located on the first outer surface S1, the fuel gas outlet 142 is located on the second outer surface S2, and the oxidant gas inlet 152 is located on one of the first outer surface S1 and the second outer surface S2, and the oxidant gas outlet 162 is located on the other. Therefore, similar to the first embodiment, the electrochemical cell stack 102 can efficiently distribute the fuel gas and oxidant gas throughout, thereby improving power generation efficiency.

[0076] Furthermore, in the electrochemical cell stack 102 of the fourth embodiment, in at least one of the pair of the fuel gas inlet 132 and the fuel gas outlet 142 and the pair of the oxidizer gas inlet 152 and the oxidizer gas outlet 162, the flow path of at least one electrochemical cell 112 located on the inlet side in the stacking direction is connected to the inlet, the flow paths of all the stacked electrochemical cells are connected to the internal flow path at a position different from the inlet as viewed from the stacking direction, and the flow paths of all the electrochemical cells 112 other than the electrochemical cell 112 connected to the inlet are connected to the outlet at a position different from the internal flow path as viewed from the stacking direction. With this configuration, the electrochemical cell stack 102 can have long flow paths through which at least one of the fuel gas and the oxidizer gas passes. Therefore, the electrochemical cell stack 102 can distribute at least one of the fuel gas and the oxidizer gas throughout the entire gas flow path, thereby improving power generation efficiency.

[0077] Those skilled in the art may make various modifications and alterations to the contents of the present disclosure based on the present disclosure. Therefore, these modifications and alterations are within the scope of the present disclosure. For example, in each embodiment, each functional unit, each means, each step, etc. may be added to other embodiments without logical inconsistency, or may be replaced with each functional unit, each means, each step, etc. of other embodiments. Furthermore, in each embodiment, multiple functional units, each means, each step, etc. may be combined into one or divided into separate units. Furthermore, each of the above-described embodiments of the present disclosure is not limited to faithful implementation of each described embodiment, but may also be implemented by combining each feature or omitting some features as appropriate. [Explanation of symbols]

[0078] 10, 100, 101, 102 Electrochemical cell stack 11, 112 Electrochemical cells 112a Inlet electrochemical cell 112b Outlet side electrochemical cell 12a, 122a First end plate 12b Second end plate 13, 130, 131, 132 Fuel gas inlet 14, 141, 142 Fuel gas outlet 15, 150, 151, 152 Oxidant gas inlet 16, 160, 161, 162 Oxidant gas outlet 17 Electrolyte membrane 18 Fuel electrode 19 Air electrode 20 Interconnector 202a Inlet side interconnector 21 frames 212a Entrance frame 212b Exit frame 22 Ridge 23, 232 First fuel gas passage hole 24, 242 Second fuel gas passage hole 25, 252 First oxidizer gas passage hole 26, 262 Second oxidizer gas passage hole 27, 272 Fuel gas supply hole 28, 282 Oxidant gas supply hole 29, 292 Fuel gas exhaust hole 30,302 Oxidant gas exhaust hole 312 Internal fuel gas flow path 322 Internal flow path for oxidant gas 332 Third fuel gas passage hole 342 Third oxidizer gas passage hole C1 First center point C2 Second center point FR fuel gas chamber IP1, IP2 intersection OR Oxidizer gas chamber S1 First outer surface S2 Second outer surface

Claims

1. An electrochemical cell stack in which plate-shaped electrochemical cells that generate electricity by an electrochemical reaction between a fuel gas and an oxidant gas are stacked, A fuel gas inlet is located on one first outer surface in the stacking direction of the electrochemical cell, and a fuel gas outlet is located on a second outer surface behind the first outer surface. an oxidant gas inlet is located on one of the first outer surface and the second outer surface, and an oxidant gas outlet is located on the other of the first outer surface and the second outer surface; the first outer surface and the second outer surface have two pairs of opposing sides, and when viewed from the stacking direction, the fuel gas inlet and the fuel gas outlet are located near one pair of opposing sides, and the oxidant gas inlet and the oxidant gas outlet are located near another pair of opposing sides that are different from the pair of opposing sides, at least one of the fuel gas inlet, the fuel gas outlet, the oxidant gas inlet, and the oxidant gas outlet is located away from one of the pair of opposing sides located near the respective inlet or outlet and away from another pair of opposing sides adjacent to the other pair of opposing sides, as viewed from the stacking direction; The fuel gas flow path from the fuel gas inlet to the fuel gas outlet includes: a fuel gas supply hole through which the fuel gas flows from the fuel gas inlet toward one direction in the stacking direction of the electrochemical cell stack; a flow path through which the fuel gas flows in a direction perpendicular to the stacking direction within the electrochemical cell; a fuel gas discharge hole through which the fuel gas flows in one direction of the stacking direction and is discharged from the fuel gas outlet, The flow path of the oxidant gas from the oxidant gas inlet to the oxidant gas outlet includes: an oxidant gas supply hole through which the oxidant gas flows from the oxidant gas inlet in one direction in the stacking direction; a flow path through which the oxidant gas flows in a direction perpendicular to the stacking direction within the electrochemical cell; an oxidant discharge hole through which the oxidant gas flows in one direction of the stacking direction and is discharged from an outlet of the oxidant gas. Electrochemical cell stack.

2. An electrochemical cell stack in which plate-shaped electrochemical cells that generate electricity by an electrochemical reaction between a fuel gas and an oxidant gas are stacked, A fuel gas inlet is located on one first outer surface in the stacking direction of the electrochemical cell, and a fuel gas outlet is located on a second outer surface behind the first outer surface. an oxidant gas inlet is located on one of the first outer surface and the second outer surface, and an oxidant gas outlet is located on the other of the first outer surface and the second outer surface; an extension of a line segment connecting the fuel gas inlet and the fuel gas outlet intersects with or is parallel to an extension of a line segment connecting the oxidant gas inlet and the oxidant gas outlet when viewed from the stacking direction, and when viewed from a direction perpendicular to the stacking direction, a line segment connecting the fuel gas inlet and outlet and a line segment connecting the oxidant gas inlet and outlet intersect with each other, The fuel gas flow path from the fuel gas inlet to the fuel gas outlet includes: a fuel gas supply hole through which the fuel gas flows from the fuel gas inlet toward one direction in the stacking direction of the electrochemical cell stack; a flow path through which the fuel gas flows in a direction perpendicular to the stacking direction within the electrochemical cell; a fuel gas discharge hole through which the fuel gas flows in one direction of the stacking direction and is discharged from the fuel gas outlet, The flow path of the oxidant gas from the oxidant gas inlet to the oxidant gas outlet includes: an oxidant gas supply hole through which the oxidant gas flows from the oxidant gas inlet in one direction in the stacking direction; a flow path through which the oxidant gas flows in a direction perpendicular to the stacking direction within the electrochemical cell; an oxidant discharge hole through which the oxidant gas flows in one direction of the stacking direction and is discharged from an outlet of the oxidant gas. Electrochemical cell stack.

3. 3. The electrochemical cell stack according to claim 1 or 2, the fuel gas inlet and the fuel gas outlet are located at both ends of the electrochemical cell stack in any one direction perpendicular to the stacking direction, The oxidant gas inlet and the oxidant gas outlet are located at both ends of the electrochemical cell stack in any one direction perpendicular to the stacking direction. Electrochemical cell stack.

4. 3. The electrochemical cell stack according to claim 2, The oxidant gas inlet is located closer to the fuel gas inlet than the center of a line segment connecting the fuel gas inlet and the fuel gas outlet when viewed from the stacking direction. Electrochemical cell stack.

5. 10. The electrochemical cell stack of claim 1, When viewed from the stacking direction, a line segment connecting the fuel gas inlet and the fuel gas outlet intersects with a line segment connecting the oxidant gas inlet and the oxidant gas outlet. Electrochemical cell stack.

6. 10. The electrochemical cell stack of claim 1, when viewed from the stacking direction, a line segment connecting the fuel gas inlet and the fuel gas outlet intersects with a line segment connecting the oxidant gas inlet and the oxidant gas outlet at an intersection point; When viewed from the stacking direction, the angle between the line segment connecting the fuel gas inlet and the intersection point and the line segment connecting the oxidant gas inlet and the intersection point is greater than 45° and less than 135°. Electrochemical cell stack.

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