Fuel cell stack

Abstract

To provide a fuel cell stack that can suppress a reduction in a flow passage cross-sectional area of a gas exhaust manifold caused by water retention.SOLUTION: A fuel cell stack is configured by stacking a plurality of power generating cells 20 in the X-axis direction that intersects with the Z-axis direction, which is the vertical direction. A fuel gas exhaust manifold M2 of the fuel cell stack is formed in a position aligned with a fuel gas flow path 51 in the Y-axis direction, which is perpendicular to both the Z-axis direction and the X-axis direction, and penetrates the plurality of power generating cells 20 in the X-axis direction. A storage portion 80 is formed at the lower part of the periphery of the fuel gas exhaust manifold M2, the cross-sectional area of which is partially reduced, for storing moisture contained in a reactant gas. The storage portion 80 of the fuel gas exhaust manifold M2 is located below the lowermost part of a connection part between the periphery of the fuel gas exhaust manifold M2 and the fuel gas flow path 51.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] Patent Document 1 discloses a fuel cell stack formed by stacking a plurality of unit cells. The unit cell has a membrane electrode assembly that generates power by being supplied with a reactant gas. The fuel cell stack has a fuel gas supply manifold that supplies a fuel gas as a reactant gas to the unit cell, and a fuel gas discharge manifold that discharges the fuel gas used for power generation. The fuel stack also has an oxidant gas supply manifold that supplies an oxidant gas as a reactant gas to the unit cell, and an oxidant gas discharge manifold that discharges the oxidant gas used for power generation. Power generation is generated by an electrochemical reaction between the fuel gas and the oxidant gas in the membrane electrode assembly of the unit cell. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-78020 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the fuel gas and the oxidant gas may be supplied to the unit cells in a pre-humidified state. Therefore, condensed water, which is the water contained in the fuel gas, may accumulate in the fuel gas supply manifold and the fuel gas exhaust manifold. In addition to the condensed water, water generated during power generation may accumulate in the oxidant gas supply manifold and the oxidant gas exhaust manifold. When water accumulates in each manifold, the flow path cross-sectional area of ​​the manifold is reduced. This may impede the smooth flow of the reactant gas, thereby reducing the power generation performance of the fuel cell stack. [Means for solving the problem]

[0005] A fuel cell stack for solving the above problem is a fuel cell stack constructed by stacking a plurality of power generation cells, each having a power generation section that generates electricity when supplied with a reactant gas, in a first direction intersecting a vertical direction, the fuel cell stack having a gas flow path that faces the power generation section and through which the reactant gas flows, and a gas supply manifold and a gas exhaust manifold that are connected to the gas flow path, the gas supply manifold and the gas exhaust manifold are formed in a position aligned with the gas flow path in a second direction that is perpendicular to both the vertical direction and the first direction, and penetrate the plurality of power generation cells in the first direction, the cross-sectional area perpendicular to the first direction is partially reduced at the lower part of the peripheral portion of the gas exhaust manifold, and a storage section that stores moisture contained in the reactant gas is formed, the storage section being located vertically below the lowermost part of the connection portion between the peripheral portion of the gas exhaust manifold and the gas flow path.

[0006] According to the above configuration, the storage section is located vertically below the lowermost part of the connection between the peripheral part of the gas exhaust manifold and the gas flow path. Therefore, water that flows into the gas exhaust manifold is easily stored in the storage section. In addition, the cross-sectional area of ​​the storage section perpendicular to the first direction is partially reduced, so the flow rate of the reaction gas flowing through the storage section is higher than the flow rate in other parts of the gas exhaust manifold. As a result, water that flows into the gas exhaust manifold and is stored in the storage section is easily able to move through the gas exhaust manifold together with the reaction gas. Therefore, it is possible to suppress a decrease in the cross-sectional area of ​​the flow path of the gas exhaust manifold caused by the retention of water. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a front view showing a vehicle equipped with a fuel cell including a fuel cell stack according to an embodiment. [Diagram 2] FIG. 2 is a perspective view showing the fuel cell of FIG. [Diagram 3]FIG. 3 is a cross-sectional view showing the fuel cell of FIG. [Figure 4] FIG. 4 is a front view showing the fuel gas flow passages of a separator that constitutes the power generating cell of FIG. [Diagram 5] FIG. 5 is a front view showing the oxidant gas flow path of a separator that constitutes the power generating cell of FIG. [Figure 6] FIG. 6 is a front view showing a fuel gas flow channel of a separator that constitutes the dummy cell of FIG. [Figure 7] FIG. 7 is an enlarged view showing the fuel gas discharge manifold of FIG. [Figure 8] FIG. 8 is a front view showing the fuel gas discharge manifold when the vehicle in FIG. 1 is tilted. [Figure 9] FIG. 9 is a front view showing a fuel gas exhaust manifold according to a first modified example. [Figure 10] FIG. 10 is a front view showing a fuel gas discharge manifold according to a second modified example. [Figure 11] FIG. 11 is a front view showing a fuel gas discharge manifold according to a third modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, one embodiment of a fuel cell stack will be described with reference to FIGS. (fuel cell 10) 1, the fuel cell 10 is mounted on a moving object 1 such as an automobile. The fuel cell 10 supplies power to a motor (not shown) that drives the moving object 1.

[0009] The fuel cell 10 includes a fuel cell stack 11, a pair of terminal plates 12, a pair of insulating plates 13, and a pair of end plates . (Fuel Cell Stack 11) The fuel cell stack 11 is configured by stacking a plurality of power generating cells 20 having a power generating function and a dummy cell 20D having no power generating function in a direction intersecting the vertical direction. The dummy cell 20D is disposed at one end of the plurality of power generating cells 20 in the stacking direction.

[0010] Hereinafter, the stacking direction of the fuel cell stack 11 may be referred to as the X-axis direction, the vertical direction may be referred to as the Z-axis direction, and the direction perpendicular to both the X-axis direction and the Z-axis direction may be referred to as the Y-axis direction. Additionally, the upper and lower sides of the Z-axis direction may be simply referred to as the upper and lower sides, respectively.

[0011] The X-axis direction is, for example, a horizontal direction perpendicular to the vertical direction. The X-axis direction coincides with the width direction of the moving body 1, which is a direction perpendicular to the moving direction of the moving body 1. Therefore, the Y-axis direction coincides with the moving direction of the moving body 1. The X-axis direction is an example of a "first direction." The Y-axis direction is an example of a "second direction."

[0012] At one end and the other end of the fuel cell stack 11 in the X-axis direction, a terminal plate 12, an insulating plate 13, and an end plate 14 are arranged, in that order from the fuel cell stack 11 side. The terminal plate 12 collects electricity from the multiple power generating cells 20. The insulating plate 13 provides insulation between the terminal plate 12 and the end plate 14. The end plate 14 applies a tightening load to the fuel cell stack 11.

[0013] 2, the fuel cell stack 11 has a fuel gas supply manifold M1, a fuel gas discharge manifold M2, an oxidant gas supply manifold M3, an oxidant gas discharge manifold M4, a coolant supply manifold M5, and a coolant discharge manifold M6. The fuel gas supply manifold M1 is located above the fuel gas discharge manifold M2. The oxidant gas supply manifold M3 is located above the oxidant gas discharge manifold M4.

[0014] The fuel gas supply manifold M1, the fuel gas discharge manifold M2, the oxidant gas supply manifold M3, and the oxidant gas discharge manifold M4 each have, for example, a rounded isosceles triangle with the upper part as the base when viewed from the front. The coolant supply manifold M5 and the coolant discharge manifold M6 each have, for example, a rounded rectangle when viewed from the front.

[0015] The fuel gas supply manifold M1 supplies fuel gas as a reactant gas to the inside of the fuel cell stack 11. The fuel gas discharge manifold M2 discharges the fuel gas to the outside of the fuel cell stack 11. The oxidant gas supply manifold M3 supplies oxidant gas as a reactant gas to the inside of the fuel cell stack 11. The oxidant gas discharge manifold M4 discharges the oxidant gas to the outside of the fuel cell stack 11. The coolant supply manifold M5 supplies a cooling medium to the inside of the fuel cell stack 11. The coolant discharge manifold M6 discharges the cooling medium to the outside of the fuel cell stack 11. The fuel gas is, for example, hydrogen. The oxidant gas is, for example, air. The cooling medium is, for example, water.

[0016] Each of the manifolds M1 to M6 penetrates all of the power generating cells 20 and the dummy cells 20D in the X-axis direction. Each of the manifolds M1 to M6 penetrates the terminal plate 12, insulating plate 13, and end plate 14 arranged on one side of the fuel cell stack 11 in the X-axis direction. On the other hand, each of the manifolds M1 to M6 does not penetrate the terminal plate 12, insulating plate 13, and end plate 14 arranged on the other side of the fuel cell stack 11 in the X-axis direction. Therefore, each of the manifolds M1 to M6 is open only to one side of the fuel cell stack 11 in the X-axis direction.

[0017] The fuel gas supplied from the fuel gas supply manifold M1 passes through each power generation cell 20 and the dummy cell 20D, and is then discharged to the outside of the fuel cell stack 11 through the fuel gas discharge manifold M2. The oxidant gas supplied from the oxidant gas supply manifold M3 passes through each power generation cell 20 and the dummy cell 20D, and is then discharged to the outside of the fuel cell stack 11 through the oxidant gas discharge manifold M4. The cooling medium supplied from the coolant supply manifold M5 passes through each power generation cell 20 and the dummy cell 20D, and is then discharged to the outside of the fuel cell stack 11 through the coolant discharge manifold M6.

[0018] The fuel gas supply manifold M1, the coolant discharge manifold M6, and the oxidant gas discharge manifold M4 are arranged in this order from top to bottom at one end in the Y axis direction of the fuel cell stack 11. The oxidant gas supply manifold M3, the coolant supply manifold M5, and the fuel gas discharge manifold M2 are arranged in this order from top to bottom at the other end in the Y axis direction of the fuel cell stack 11.

[0019] (Power generating cell 20) 3, the power generating cell 20 includes a power generating section 30, a frame 40, and a pair of separators 50, 60. The power generating section 30 is sheet-shaped. The frame 40 surrounds the outer periphery of the power generating section 30. The pair of separators 50, 60 sandwich the power generating section 30 and the frame 40.

[0020] Although not shown, the frame 40 and the pair of separators 50, 60 are formed with through holes that form the manifolds M1 to M6. The power generation section 30 has a membrane electrode assembly, and an anode side gas diffusion layer and a cathode side gas diffusion layer that sandwich the membrane electrode assembly. The membrane electrode assembly has an electrolyte membrane, and an anode electrode catalyst layer and a cathode electrode catalyst layer that sandwich the electrolyte membrane.

[0021] The frame 40 is made of an insulating resin material and has a receiving hole 41 in the center thereof for receiving the power generating unit 30 therein. The separators 50, 60 are formed by press-molding a metal plate such as stainless steel or titanium alloy.

[0022] The separator 50 is disposed on the anode side surface of the power generation section 30. The separator 60 is disposed on the cathode side surface of the power generation section 30. A fuel gas flow passage 51 through which a fuel gas flows is formed on the surface of the separator 50 facing the anode side surface of the power generation section 30. An oxidant gas flow passage 61 through which an oxidant gas flows is formed on the surface of the separator 60 facing the cathode side surface of the power generation section 30. The fuel gas flow passage 51 and the oxidant gas flow passage 61 are formed by a plurality of grooves arranged in parallel.

[0023] As shown in FIG. 4, the fuel gas flow path 51 is formed at a position aligned with the fuel gas supply manifold M1 and the fuel gas discharge manifold M2 in the Y-axis direction. The fuel gas flow passage 51 has a main flow passage 52, a supply side connecting flow passage 53, and a discharge side connecting flow passage .

[0024] The main flow path 52 faces the power generation section 30 and extends in the Y-axis direction. The supply side connection flow passage 53 connects the main flow passage 52 and the fuel gas supply manifold M1. The supply side connection flow passage 53 has an inclined portion 53a and a straight portion 53b. The inclined portion 53a extends from the main flow passage 52 at an angle with respect to the Y-axis direction and the Z-axis direction. The straight portion 53b extends linearly from the main flow passage 52 or the inclined portion 53a in the Y-axis direction and is connected to the fuel gas supply manifold M1.

[0025] The discharge side connecting flow passage 54 connects the main flow passage 52 and the fuel gas discharge manifold M2. The discharge side connecting flow passage 54 has an inclined portion 54a and a straight portion 54b. The inclined portion 54a extends from the main flow passage 52 at an angle with respect to the Y-axis direction and the Z-axis direction. The straight portion 54b extends linearly from the main flow passage 52 or the inclined portion 54a in the Y-axis direction and is connected to the fuel gas discharge manifold M2.

[0026] As shown in FIG. 5, the oxidizing gas flow path 61 is formed at a position aligned with the oxidizing gas supply manifold M3 and the oxidizing gas discharge manifold M4 in the Y-axis direction. The oxidizing gas flow path 61 has a main flow path 62 , a supply side connecting flow path 63 , and a discharge side connecting flow path 64 .

[0027] The main flow path 62 faces the power generation section 30 and extends in the Y-axis direction. The supply-side connection flow passage 63 connects the main flow passage 62 and the oxidizing gas supply manifold M3. The supply-side connection flow passage 63 has an inclined portion 63a and a straight portion 63b. The inclined portion 63a extends from the main flow passage 62 at an angle with respect to the Y-axis direction and the Z-axis direction. The straight portion 63b extends linearly from the main flow passage 62 or the inclined portion 63a in the Y-axis direction and is connected to the oxidizing gas supply manifold M3.

[0028] The discharge side connecting flow passage 64 connects the main flow passage 62 and the oxidant gas discharge manifold M4. The discharge side connecting flow passage 64 has an inclined portion 64a and a straight portion 64b. The inclined portion 64a extends from the main flow passage 62 at an angle with respect to the Y-axis direction and the Z-axis direction. The straight portion 64b extends linearly from the main flow passage 62 or the inclined portion 64a in the Y-axis direction and is connected to the oxidant gas discharge manifold M4.

[0029] 3, a cooling channel 55 through which a coolant flows is formed on the side of the separator 50 opposite to the side on which the fuel gas channel 51 is formed. A cooling channel 65 through which a coolant flows is formed on the side of the separator 60 opposite to the side on which the oxidant gas channel 61 is formed. The cooling channels 55, 65 are connected to a coolant supply manifold M5 and a coolant discharge manifold M6. The coolant flows through a space partitioned by the cooling channels 55, 65 of the separators 50, 60 that are in contact with each other in the X-axis direction.

[0030] (Dummy cell 20D) The dummy cell 20D is stacked downstream of the multiple power generating cells 20 in the flow direction of the fuel gas flowing through the fuel gas supply manifold M1.

[0031] The dummy cell 20D includes a conductive member 70, a frame 40, and a pair of separators 150, 60. In place of the power generation section 30 of the power generation cell 20, the dummy cell 20D has a conductive member 70 arranged therein that has a shape corresponding to the shape of the power generation section 30. Therefore, even if a reactant gas flows inside the dummy cell 20D, the dummy cell 20D does not generate electricity.

[0032] The frame 40 and the separator 60 of the dummy cell 20D have the same configurations as the frame 40 and the separator 60 of the power generating cell 20, respectively. The separator 150 of the dummy cell 20D has a fuel gas flow path 151 with a different shape from the separator 50 of the power generating cell 20. The difference between the fuel gas flow path 151 of the dummy cell 20D and the fuel gas flow path 51 of the power generating cell 20 is the number of straight portions 53b of the supply side connection flow path 53. The number of straight portions 53b of the dummy cell 20D is greater than the number of straight portions 53b of the power generating cell 20. Since the configuration of the fuel gas flow path 151 is the same as the configuration of the fuel gas flow path 51 except for the number of straight portions 53b, a reference numeral indicating the configuration of the fuel gas flow path 51 will be used and a detailed description of the fuel gas flow path 151 will be omitted.

[0033] (Storage section 80) As shown in Figures 4 to 6, a reservoir 80 is formed in the lower part of the periphery of the fuel gas supply manifold M1, in which the area of ​​a cross section perpendicular to the X-axis direction (hereinafter referred to as the cross-sectional area) is partially reduced. The reservoir 80 has a function of storing moisture contained in the reactant gas. The reservoir 80 extends over the entire fuel gas supply manifold M1 in the X-axis direction.

[0034] Similarly, a storage portion 80 is formed at the lower portion of the periphery of each of the fuel gas discharge manifold M2, the oxidant gas supply manifold M3, and the oxidant gas discharge manifold M4. The storage portions 80 of the manifolds M1 to M4 have the same configuration.

[0035] Next, the storage section 80 of the fuel gas supply manifold M1 and the storage section 80 of the fuel gas exhaust manifold M2 will be described in detail. Hereinafter, the storage section 80 of the fuel gas supply manifold M1 can be read as the storage section 80 of the oxidizing gas supply manifold M3. Also, the storage section 80 of the fuel gas exhaust manifold M2 can be read as the storage section 80 of the oxidizing gas exhaust manifold M4.

[0036] 4, the portion of the storage section 80 of the fuel gas supply manifold M1 that constitutes the power generating cell 20 is located below the lowermost portion of the connection between the periphery of the fuel gas supply manifold M1 and the fuel gas flow path 51. In other words, the storage section 80 in the power generating cell 20 is located below the lowermost straight section 53b of the multiple straight sections 53b of the supply side connection flow path 53. In other words, the straight section 53b of the supply side connection flow path 53 is connected to the fuel gas supply manifold M1 at a position above the storage section 80 on the periphery of the fuel gas supply manifold M1.

[0037] The portion of the storage section 80 of the fuel gas discharge manifold M2 that constitutes the power generating cell 20 is located below the lowermost portion of the connection portion between the periphery of the fuel gas discharge manifold M2 and the fuel gas flow path 51. In other words, the storage section 80 in the power generating cell 20 is located below the lowermost straight section 54b of the multiple straight sections 54b of the discharge side connection flow path 54. In other words, the straight section 54b of the discharge side connection flow path 54 is connected to the fuel gas discharge manifold M2 at a position above the storage section 80 on the periphery of the fuel gas discharge manifold M2.

[0038] 7, the storage section 80 has a pair of side walls 81 facing each other in the Y-axis direction. The pair of side walls 81 are inclined with respect to the Z-axis direction so as to approach each other downward. The inclination angle α of the pair of side walls 81 with respect to the Y-axis direction is the same.

[0039] As shown in Fig. 8, the moving body 1 (see Fig. 1) may be inclined with respect to the horizontal direction when moving, for example, on a slope. The inclination angle α of the pair of side walls 81 with respect to the Y-axis direction is set to be larger than the maximum inclination angle αm, which is the maximum inclination angle of the moving body 1 with respect to the horizontal direction that is assumed when the moving body 1 moves. The maximum inclination angle αm is, for example, 15° to 30°.

[0040] The corners of the periphery of each of the manifolds M1 to M6, including the lower ends of the pair of side walls 81, have an arc-shaped cross section perpendicular to the X-axis direction. Providing such arc-shaped portions makes it easier to punch out the separators 50, 60, 150 to form the through-holes that make up each of the manifolds M1 to M6, compared to when the corners are angular.

[0041] As shown in FIG. 6, a portion of the storage section 80 of the fuel gas supply manifold M1 that constitutes the dummy cell 20D is connected to the fuel gas flow path 151 of the dummy cell 20D. More specifically, a portion of the storage section 80 of the fuel gas supply manifold M1 that constitutes the dummy cell 20D is connected to one or more straight portions 53b in the supply side connection flow path 53 of the dummy cell 20D. The one or more straight portions 53b, for example, extend branching from one inclined portion 53a and open to the storage section 80. The one or more straight portions 53b are located below the supply side connection flow path 53 of the power generation cell 20. Note that a portion of the storage section 80 of the fuel gas discharge manifold M2 that constitutes the dummy cell 20D is not connected to the fuel gas flow path 151 of the dummy cell 20D. Although not shown, the portions of the storage portions 80 of the oxidizing gas supply manifold M3 and the oxidizing gas discharge manifold M4 that constitute the dummy cell 20D are not connected to the oxidizing gas flow path of the dummy cell 20D.

[0042] The operation of this embodiment will be described. The storage section 80 of the fuel gas discharge manifold M2 is located below the lowermost part of the connection between the periphery of the fuel gas discharge manifold M2 and the fuel gas flow path 51. Therefore, water that flows into the fuel gas discharge manifold M2 is likely to be stored in the storage section 80. In addition, since the cross-sectional area of ​​the storage section 80 is partially reduced, the flow rate of the reactant gas flowing through the storage section 80 is greater than the flow rate in other parts of the fuel gas discharge manifold M2. The above also applies to the oxidant gas discharge manifold M4.

[0043] The effects of this embodiment will be described. (1) The cross-sectional area is partially reduced at the lower part of the peripheral portion of the fuel gas exhaust manifold M2 and the oxidant gas exhaust manifold M4 to form a storage portion 80 for storing moisture contained in the reactant gas. The storage portion 80 of the fuel gas exhaust manifold M2 is located below the lowermost part of the connection portion between the peripheral portion of the fuel gas exhaust manifold M2 and the fuel gas flow path 51. The storage portion 80 of the oxidant gas exhaust manifold M4 is located below the lowermost part of the connection portion between the peripheral portion of the oxidant gas exhaust manifold M4 and the oxidant gas flow path 61.

[0044] According to the above configuration, the water that flows into the fuel gas discharge manifold M2 and is stored in the storage section 80 can easily move through the fuel gas discharge manifold M2 together with the reactant gas, thereby suppressing a reduction in the flow passage cross-sectional area of ​​the fuel gas discharge manifold M2 caused by the accumulation of water. The above also applies to the oxidant gas discharge manifold M4.

[0045] (2) A storage portion 80 is formed below the peripheral portions of the fuel gas supply manifold M1 and the oxidant gas supply manifold M3. The storage portion 80 of the fuel gas supply manifold M1 is located below the connection portion between the peripheral portion of the fuel gas supply manifold M1 and the fuel gas flow path 51. The storage portion 80 of the oxidant gas supply manifold M3 is located below the connection portion between the peripheral portion of the oxidant gas supply manifold M3 and the oxidant gas flow path 61.

[0046] According to the above configuration, water that flows into the fuel gas supply manifold M1 is more likely to be stored in the storage section 80. Also, the flow rate of the reactant gas flowing through the storage section 80 is greater than the flow rate in other parts of the fuel gas supply manifold M1. As a result, water that flows into the fuel gas supply manifold M1 and is stored in the storage section 80 is more likely to move through the fuel gas supply manifold M1 together with the reactant gas. Therefore, a reduction in the flow path cross-sectional area of ​​the fuel gas supply manifold M1 due to water retention can be suppressed. The above also applies to the oxidant gas supply manifold M3.

[0047] (3) The portion of the storage portion 80 of the fuel gas supply manifold M1 that constitutes the dummy cell 20D is connected to the fuel gas flow path 151 of the dummy cell 20D. According to the above configuration, when water is stored in the storage section 80 of the fuel gas supply manifold M1, the water flows from the portion of the storage section 80 that constitutes the dummy cell 20D toward the fuel gas flow path 151 of the dummy cell 20D. The water is then discharged to the outside from the fuel gas discharge manifold M2. This makes it difficult for water to flow into the fuel gas flow path 51 of the power generating cell 20 that has a power generating function, while water is more likely to flow into the fuel gas flow path 151 of the dummy cell 20D that does not have a power generating function. This makes it possible to suppress a decrease in the power generating performance of the fuel cell stack 11.

[0048] (4) The cross-sectional area of ​​the storage section 80 gradually decreases toward the bottom. According to the above configuration, the flow rate of the reactant gas flowing through the storage portion 80 increases downward. Therefore, the smaller the amount of water stored in the storage portion 80, the higher the flow rate of the reactant gas flowing through the storage portion 80. This makes it easier for the water stored in the storage portion 80 to move quickly through each of the manifolds M1 to M4 together with the reactant gas. This can improve the drainage performance in each of the manifolds M1 to M4.

[0049] (5) The pair of side walls 81 of the storage portion 80 are inclined with respect to the Z-axis direction so as to approach each other downward. According to the above configuration, water adhering to the side wall 81 of the storage section 80 easily moves downward along the side wall 81. Since the flow velocity of the reactant gas flowing through the storage section 80 increases toward the bottom, the water that moves downward along the side wall 81 easily moves inside each of the manifolds M1 to M4 together with the reactant gas. This further improves the drainage performance in each of the manifolds M1 to M4.

[0050] (6) The inclination angle α of each of the pair of side walls 81 of the storage section 80 with respect to the horizontal direction is greater than the maximum inclination angle αm. 8, even if the fuel cell stack 11 is tilted relative to the horizontal direction as a result of the attitude of the fuel cell stack 11 changing with the movement of the moving body 1, the side wall 81 maintains an attitude with a downward slope toward the storage section 80. Therefore, it is possible to prevent the water stored in the storage section 80 from flowing into the fuel gas flow path 51 or the oxidant gas flow path 61.

[0051] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0052] The inclination angles α of the pair of side walls 81 in the storage section 80 may be different from each other. The inclination angle α of at least one of the pair of side walls 81 in the storage section 80 may be smaller than the maximum inclination angle αm.

[0053] The fuel cell stack 11 is not limited to being mounted on the moving object 1. The fuel cell stack 11 may be, for example, a stationary type fuel cell stack 11. As shown in FIG. 9, one of a pair of side walls 81 in the storage section 80 may extend in the Z-axis direction.

[0054] The shape of each of the manifolds M1 to M4, excluding the storage section 80, may be any shape. For example, as shown in Fig. 10, the cross-sectional area of ​​the upper portion of the fuel gas discharge manifold M2 may be gradually reduced toward the top. Also, as shown in Fig. 11, the fuel gas discharge manifold M2 may have an asymmetric shape in the Y-axis direction.

[0055] The cross-sectional area of ​​the storage section 80 may decrease stepwise downward. In this case, it is sufficient that the distance between the pair of side walls 81 in the Y-axis direction decreases stepwise downward.

[0056] The storage portion 80 may be a groove formed in the bottom surface of the fuel gas exhaust manifold M2. In this case, the cross-sectional area of ​​the storage portion 80 may be constant in the Z-axis direction as long as it is smaller than the cross-sectional area of ​​the other portions.

[0057] The fuel gas flow path 151 of the dummy cell 20D may be connected to the bottom surface of the portion of the storage section 80 that constitutes the dummy cell 20D. The portion of the storage portion 80 of the fuel gas discharge manifold M2 that constitutes the dummy cell 20D may be connected to the fuel gas flow path 151 of the dummy cell 20D.

[0058] A portion of the storage section 80 of at least one of the oxidizing gas supply manifold M3 and the oxidizing gas discharge manifold M4 that constitutes the dummy cell 20D may be connected to an oxidizing gas flow path (not shown) of the dummy cell 20D.

[0059] The dummy cell 20D may be disposed between a plurality of power generating cells 20. In other words, the dummy cell 20D may be sandwiched between the power generating cells 20. The dummy cells 20D may be disposed at both ends of the plurality of power generating cells 20 in the X-axis direction.

[0060] The fuel cell stack 11 does not necessarily have to include the dummy cell 20D. At least one of the fuel gas supply manifold M1 and the oxidizing gas supply manifold M3 does not necessarily have to have the storage section 80 formed therein.

[0061] The storage section 80 may be formed in only one of the fuel gas discharge manifold M2 and the oxidant gas discharge manifold M4. At least a portion of each of the supply side connecting flow paths 53, 63 and the discharge side connecting flow paths 54, 64 may be formed by a communication hole that penetrates the frame 40 and communicates with any of the manifolds M1 to M4.

[0062] The X-axis direction, which is the stacking direction of the power generating cells 20, may be inclined with respect to both the vertical direction and the horizontal direction. The above-mentioned modifications to the fuel gas discharge manifold M2 can also be applied to the manifolds M1, M3, and M4. [Explanation of symbols]

[0063] α…Inclination angle αm…Maximum tilt angle M1…Fuel gas supply manifold M2…Fuel gas exhaust manifold M3…Oxidant gas supply manifold M4…Oxidant gas exhaust manifold M5…Refrigerant supply manifold M6…Refrigerant discharge manifold 1. Mobile object 10…fuel cell 11...Fuel cell stack 12…Terminal plate 13…Insulating plate 14…End plate 20…Power generation cell 20D…Dummy cell 30…Power generation section 40…Frame 41...Housing hole 50, 60, 150...Separator 51,151…Fuel gas flow path 52,62…Main flow path 53, 63...Supply side connection flow path 53a, 63a, 54a, 64a...Slope part 53b,63b,54b,64b...Straight section 54, 64…Discharge side connection flow passage 55,65…Cooling channel 61...Oxidant gas flow path 70...Conductive material 80…Storage section 81...Side wall

Claims

1. A fuel cell stack including a plurality of power generation cells, each having a power generation section that generates electricity when a reactant gas is supplied thereto, stacked in a first direction intersecting a vertical direction, a gas flow passage facing the power generation unit and through which the reactant gas flows, and a gas supply manifold and a gas exhaust manifold connected to the gas flow passage, the gas supply manifold and the gas exhaust manifold are formed at positions aligned with the gas flow passage in a second direction perpendicular to both the vertical direction and the first direction, and penetrate the plurality of power generation cells in the first direction, a reservoir portion is formed in a lower portion of a peripheral portion of the gas exhaust manifold, the reservoir portion having a cross-sectional area perpendicular to the first direction that is partially reduced, the cross-sectional area being configured to retain moisture contained in the reaction gas; The storage portion is located vertically below a lowermost portion of a connection portion between a peripheral portion of the gas exhaust manifold and the gas flow path. Fuel cell stack.

2. The reservoir is formed in a lower portion of a peripheral portion of the gas supply manifold, the storage portion of the gas supply manifold is located vertically below a connection portion between a peripheral portion of the gas supply manifold and the gas flow path; The fuel cell stack of claim 1 .

3. When the flow direction of the reaction gas flowing through the gas supply manifold is simply defined as the flow direction, a dummy cell that is stacked downstream of the plurality of power generating cells in the flow direction and has no power generating function; the dummy cell has a gas flow path through which the reaction gas flows, the gas supply manifold and the gas exhaust manifold pass through the dummy cell and are connected to a gas flow path of the dummy cell; a portion of the storage portion of the gas supply manifold that constitutes the dummy cell is connected to a gas flow path of the dummy cell; The fuel cell stack of claim 2 .

4. The area of ​​the storage portion gradually decreases downward in the vertical direction. The fuel cell stack according to any one of claims 1 to 3.

5. The storage portion has a pair of side walls facing each other in the second direction, The pair of side walls are inclined with respect to the vertical direction so as to approach each other downward in the vertical direction. The fuel cell stack of claim 4.

6. the fuel cell stack is mounted on the moving body in a position in which the second direction coincides with a direction of movement of the moving body, When the maximum value of the tilt angle of the moving body with respect to the horizontal direction assumed during the movement of the moving body is defined as a maximum tilt angle, an inclination angle of each of the pair of side walls with respect to the second direction is greater than the maximum inclination angle; The fuel cell stack of claim 5 .

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