FUEL CELL STACK

Abstract

A fuel cell stack comprises power-generating cells stacked in a first direction orthogonal to a vertical direction. The fuel cell stack includes a gas port, a gas supply distributor, and a gas discharge distributor. The gas supply distributor and the gas discharge distributor are located at a point aligned with the gas port in a second direction and extend through the power-generating cells in the first direction. A lower portion of a circumferential edge of the gas discharge distributor includes a reservoir. Within the reservoir, an area of ​​a cross-section orthogonal to the first direction is partially reduced. The reservoir is located vertically below the lowest portion of a section connecting the circumferential edge of the gas discharge distributor to the gas port.

Description

BACKGROUND1. Area

[0001] The present disclosure relates to a fuel cell stack. 2. Description of the state of the art

[0002] JP 2018 - 78 020 A discloses a fuel cell stack with stacked cells. Each cell has a membrane electrode assembly that generates electricity when supplied with reactant gases. The fuel cell stack has a fuel gas supply manifold that supplies fuel gas to the cells as a reactant gas and a fuel gas discharge manifold that discharges the fuel gas used to generate electricity. Furthermore, the fuel stack has an oxidant gas supply manifold that supplies oxidant gas to the cells as a reactant gas and an oxidant gas discharge manifold that discharges the oxidant gas used to generate electricity. Electricity is generated in the membrane electrode assembly of each cell through an electrochemical reaction between the fuel gas and the oxidant gas.

[0003] The fuel gas and the oxidizing gas may be supplied to the cells in a humidified state. Thus, condensed water from the moisture contained in the fuel gas may accumulate in the fuel gas supply manifold and the fuel gas discharge manifold. Furthermore, in addition to the condensed water, water generated during power generation may accumulate in the oxidizing gas supply manifold and the oxidizing gas discharge manifold. If water accumulates in each manifold, the flow area of ​​the manifold decreases. This may impede the smooth flow of the reactant gases, leading to a decrease in the power generation capacity of the fuel cell stack. SUMMARY

[0004] This Summary is intended to introduce, in a simplified form, a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify the key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0005] A fuel cell stack according to an embodiment of the present disclosure includes power generation cells stacked in a first direction intersecting a vertical direction. Each of the power generation cells has a power generation section that generates power when supplied with reactant gas. The fuel cell stack also has a gas passage facing the power generation section and through which the reactant gas flows. The fuel cell stack further includes a gas supply manifold and a gas discharge manifold connected to the gas passage. The gas supply manifold and the gas discharge manifold are each located at a location aligned with the gas passage in a second direction and extend through the power generation cells in the first direction. The second direction is orthogonal to the vertical direction and the first direction.A lower portion of a peripheral edge of the gas discharge manifold includes a reservoir in which an area of ​​a cross-section orthogonal to the first direction is partially reduced. The reservoir is configured to store moisture contained in the reaction gas. The reservoir is located vertically below a lowermost part of a portion connecting the peripheral edge of the gas discharge manifold to the gas passage.

[0006] Further features and embodiments will become apparent from the following detailed description, drawings and claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a front view illustrating a mobile unit on which a fuel cell having a fuel cell stack according to an embodiment is mounted. Fig. 2 is a perspective view of the Fig. 1 shown fuel cell. Fig. 3 is a cross-sectional view of the Fig. 1 shown fuel cell. Fig. 4 is a front view of the fuel gas passage of the separator shown in Fig. 1 shown power generation cell. Fig. 5 is a front view of the oxidizing gas passage of the separator used in the Fig. 1 shown power generation cell. Fig. 6 is a front view of the fuel gas passage of the separator shown in Fig. 1 shown dummy cell. Fig. 7 is an enlarged view of the Fig. 4 shown fuel gas delivery manifold. Fig. 8 is a front view of the fuel gas discharge manifold when the Fig. The mobile unit shown in Figure 1 is tilted. Fig. 9 is a front view of the fuel gas discharge manifold according to a first modification. Fig. 10 is a front view of the fuel gas discharge manifold according to a second modification. Fig. 11 is a front view of the fuel gas discharge manifold according to a third modification. DETAILED DESCRIPTION

[0007] This description provides a comprehensive understanding of the described methods, devices, and / or systems. Modifications and equivalents to the described methods, devices, and / or systems will be apparent to those skilled in the art. Sequences of operating steps are exemplary and may be changed as would be apparent to one skilled in the art, except for those steps that necessarily occur in a particular order. Descriptions of functions and structures well known to one skilled in the art may be omitted.

[0008] Exemplary embodiments may take various forms and are not limited to the described examples. However, the described examples are thorough and complete, and will fully convey the scope of the disclosure to one skilled in the art.

[0009] In this description, “at least one of A and B” should be understood to mean “only A, only B, or both A and B”.

[0010] With reference to the Fig. 1 to 8, a fuel cell stack according to an embodiment will now be described. Fuel cell 10

[0011] As in Fig. As shown in Figure 1, the fuel cell 10 is mounted on a mobile unit such as a car. The fuel cell 10 supplies power to a motor (not shown) that drives the mobile unit 1.

[0012] The fuel cell 10 has a fuel cell stack 11, two connection plates 12, two insulating plates 13 and two end plates 14. Fuel cell stack 11

[0013] The fuel cell stack 11 is formed by stacking power generation cells 20 that generate power and a dummy cell 20D that does not generate power. The power generation cells 20 are stacked in a direction that intersects the vertical direction. The dummy cell 20D is located at one end of the power generation cells 20 in the stacking direction.

[0014] Hereinafter, the stacking direction of the fuel cell stack 1 may be referred to as the X-axis direction, the vertical direction may be referred to as the Z-axis direction, and the direction orthogonal to the X-axis direction and the Z-axis direction may be referred to as the Y-axis direction. Furthermore, the upper side and the lower side in the Z-axis direction may be simply referred to as the top side and the bottom side, respectively.

[0015] For example, the X-axis direction is a horizontal direction that is orthogonal to the vertical direction. The X-axis direction corresponds to the width direction of the mobile unit 1, which is orthogonal to the direction in which the mobile unit 1 moves. Thus, the Y-axis direction corresponds to the direction of movement of the mobile unit 1. The X-axis direction is an example of a first direction. The Y-axis direction is an example of a second direction.

[0016] The terminal plate 12, the insulating plate 13, and the end plate 14 are arranged sequentially at each of one end and the other end of the fuel cell stack 11 in the X-axis direction. The terminal plate 12 collects power from the power generation cells 20. The insulating plate 13 insulates between the terminal plate 12 and the end plate 14. The end plate 14 applies a clamping load to the fuel cell stack 11.

[0017] As in Fig. As shown in Figure 2, the fuel cell stack 11 includes a fuel gas supply manifold M1, a fuel gas discharge manifold M2, an oxidizing gas supply manifold M3, an oxidizing 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 oxidizing gas supply manifold M3 is located above the oxidizing gas discharge manifold M4.

[0018] The fuel gas supply manifold M1, the fuel gas discharge manifold M2, the oxidizing gas supply manifold M3, and the oxidizing gas discharge manifold M4, viewed from the front, have the shape of, for example, a rounded isosceles triangle with the base at the top. The coolant supply manifold M5 and the coolant discharge manifold M6, viewed from the front, have the shape of, for example, a rounded rectangle.

[0019] The fuel gas supply manifold M1 supplies fuel gas as a reaction gas to the interior of the fuel cell stack 11. The fuel gas discharge manifold M2 discharges fuel gas to the exterior of the fuel cell stack 11. The oxidizing gas supply manifold M3 supplies oxidizing gas as a reaction gas to the interior of the fuel cell stack 11. The oxidizing gas discharge manifold M4 discharges oxidizing gas to the exterior of the fuel cell stack 11. The coolant supply manifold M5 supplies a coolant to the interior of the fuel cell stack 11. The coolant discharge manifold M6 discharges coolant to the exterior of the fuel cell stack 11. The fuel gas is, for example, hydrogen. The oxidizing gas is, for example, air. The coolant is, for example, water.

[0020] The manifolds M1 to M6 extend in the X-axis direction through all of the power generation cells 20 and the dummy cell 20D. The manifolds M1 to M6 extend through the terminal plate 12, the insulating plate 13, and the end plate 14, which are arranged on one side of the fuel cell stack 11 in the X-axis direction. The manifolds M1 to M6 do not extend through the terminal plate 12, the insulating plate 13, and the end plate 14, which are arranged on the other side of the fuel cell stack 11 in the X-axis direction. Thus, the manifolds M1 to M6 are open only on one side of the fuel cell stack 11 in the X-axis direction.

[0021] The fuel gas supplied from the fuel gas supply manifold M1 flows through the power generation cells 20 and the dummy cell 20D, and is then discharged outside the fuel cell stack 11 through the fuel gas discharge manifold M2. The oxidizing gas supplied from the oxidizing gas supply manifold M3 flows through the power generation cells 20 and the dummy cell 20D, and is then discharged outside the fuel cell stack 11 through the oxidizing gas discharge manifold M4. The coolant supplied from the coolant supply manifold M5 flows through the power generation cells 20 and the dummy cell 20D, and is then discharged outside the fuel cell stack 11 through the coolant discharge manifold M6.

[0022] At one end of the fuel cell stack 11 in the Y-axis direction, the fuel gas supply manifold M1, the coolant discharge manifold M6, and the oxidizing gas discharge manifold M4 are arranged in this order from top to bottom. At the other end of the fuel cell stack 11 in the Y-axis direction, the oxidizing 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. Power generation cell 20

[0023] As in Fig. As shown in Figure 3, each power generation cell 20 includes a power generation section 30, a frame 40, and two separators 50, 60. The power generation section 30 is in the form of a sheet. The frame 40 surrounds the outer edge of the power generation section 30. The power generation section 30 and the frame 40 are held between the two separators 50, 60.

[0024] The frame 40 and the two separators 50, 60 each have a through hole defined by the distributors M1 to M6.

[0025] The power generation section 30 includes a membrane-electrode assembly, an anode-side gas diffusion layer, and a cathode-side gas diffusion layer. The membrane-electrode assembly is held between the anode-side gas diffusion layer and the cathode-side gas diffusion layer. The membrane-electrode assembly includes an electrolyte membrane, an anode catalyst layer, and a cathode catalyst layer. The electrolyte membrane is held between the anode catalyst layer and the cathode catalyst.

[0026] The frame 40 is made of insulating plastic. The frame has a housing hole 41 at its central portion to accommodate the power generation section 30.

[0027] The separators 50, 60 are formed by pressing a metal plate (e.g., a plate made of stainless steel or titanium alloy).

[0028] The separator 50 is located on an anode-side surface of the power generation section 30. The separator 60 is located on a cathode-side surface of the power generation section 30.

[0029] The surface of the separator 50 facing the anode-side surface of the power generation section 30 has a fuel gas passage 51 through which fuel gas flows. The surface of the separator 60 facing the cathode-side surface of the power generation section 30 has an oxidizing gas passage 61 through which oxidizing gas flows. The fuel gas passage 51 and the oxidizing gas passage 61 are defined by grooves arranged side by side.

[0030] As in Fig. 4, the fuel gas passage 51 is located at a position aligned in the Y-axis direction with the fuel gas supply manifold M1 and the fuel gas discharge manifold M2.

[0031] The fuel gas passage 51 has a main passage 52, a supply-side connecting passage 53 and a discharge-side connecting passage 54.

[0032] The main passage 52 faces the power generation section 30 and extends in the Y-axis direction.

[0033] The supply-side connecting passage 53 connects the main passage 52 to the fuel gas supply manifold M1. The supply-side connecting passage 53 has inclined portions 53a and straight portions 53b. The inclined portions 53a extend from the main passage 52 and are inclined with respect to the Y-axis direction and the Z-axis direction. The straight portions 53b extend straight in the Y-axis direction from the main passage 52 or the inclined portions 53a and are connected to the fuel gas supply manifold M1.

[0034] The discharge-side connecting passage 54 connects the main passage 52 to the fuel gas discharge manifold M2. The discharge-side connecting passage 54 has inclined portions 54a and straight portions 54b. The inclined portions 54a extend from the main passage 52 and are inclined with respect to the Y-axis direction and the Z-axis direction. The straight portions 54b extend straight in the Y-axis direction from the main passage 52 or the inclined portions 54a and are connected to the fuel gas discharge manifold M2.

[0035] As in Fig. 5, the oxidizing gas passage 61 is located at a position aligned in the Y-axis direction with the oxidizing gas supply manifold M3 and the oxidizing gas discharge manifold M4.

[0036] The oxidizing gas passage 61 has a main passage 62, a supply-side connecting passage 63 and a discharge-side connecting passage 64.

[0037] The main passage 62 faces the power generation section 30 and extends in the Y-axis direction.

[0038] The supply-side connecting passage 63 connects the main passage 62 to the oxidizing gas supply manifold M3. The supply-side connecting passage 63 has inclined portions 63a and straight portions 63b. The inclined portions 63a extend from the main passage 62 and are inclined with respect to the Y-axis direction and the Z-axis direction. The straight portions 63b extend straight in the Y-axis direction from the main passage 62 and the inclined portions 63a and are connected to the oxidizing gas supply manifold M3.

[0039] The discharge-side connecting passage 64 connects the main passage 62 to the oxidizing gas discharge manifold M4. The discharge-side connecting passage 64 has inclined portions 64a and straight portions 64b. The inclined portions 64a extend from the main passage 62 and are inclined with respect to the Y-axis direction and the Z-axis direction. The straight portions 64b extend straight in the Y-axis direction from the main passage 62 or the inclined portions 64a and are connected to the oxidizing gas discharge manifold M4.

[0040] As in Fig. As shown in Figure 3, the back surface of the separator 50, in which the fuel gas passage 51 is formed, has a cooling passage 55 through which a coolant flows. The back surface of the separator 60, in which the oxidizing gas passage 61 is formed, has a cooling passage 65 through which a coolant flows. The cooling passages 55, 65 are connected to the coolant supply manifold M5 and the coolant discharge manifold M6. The coolant flows through the space defined by the cooling passages 55, 65 of the separators 50, 60, which are in contact with each other in the X-axis direction. Dummy cell 20D

[0041] The dummy cell 20D is stacked on the downstream side of the power generation cells 20 in the flow direction of the fuel gas flowing through the fuel gas supply manifold M1.

[0042] The dummy cell 20D includes a conductive element 70, a frame 40, and two separators 50, 60. In the dummy cell 20D, the power generation section 30 of each power generation cell 20 is replaced by the conductive element 70, which is shaped in accordance with the power generation section 30. Therefore, even if reaction gas flows into the dummy cell 20D, the dummy cell 20D does not generate power.

[0043] The frame 40 and the separator 60 of the dummy cell 20D each have the same configuration as the frame 40 and the separator 60 of each power generation cell 20.

[0044] The separator 150 of the dummy cell 20D has a fuel gas passage 151 having a different shape from that of the separator 50 of the power generation cell 20. The difference between the fuel gas passage 151 of the dummy cell 20D and the fuel gas passage 51 of the power generation cell 20 is the number of straight sections 53b in the supply-side connection passage 53. The number of straight sections 53b in the dummy cell 20D is greater than the number of straight sections 53b in the power generation cell 20. The configuration of the fuel gas passage 151 is the same as that of the fuel gas passage 51 except for the number of straight sections 53b. Thus, the constituent parts of the fuel gas passage 51 are assigned reference numerals, and therefore the fuel gas passage 151 will not be described in detail. Reservoir 30

[0045] As in the Fig. As shown in FIGS. 4 to 6, a lower portion of a peripheral edge of the fuel gas supply manifold M1 includes a reservoir 80. In the reservoir 80, the area of ​​the cross section orthogonal to the X-axis direction (hereinafter referred to as the cross-sectional area) is partially reduced. The reservoir 80 stores the moisture contained in the reaction gas. The reservoir 80 extends in the X-axis direction across the entire fuel gas supply manifold M1.

[0046] Accordingly, a lower portion of a peripheral edge of each of the fuel gas discharge manifold M2, the oxidizing gas supply manifold M3, and the oxidizing gas discharge manifold M4 includes the reservoir 80. The reservoirs 80 of the manifolds M1 to M4 have the same configuration.

[0047] The reservoir 80 of the fuel gas supply manifold M1 and the reservoir 80 of the fuel gas discharge manifold M2 will now be described in detail. Hereinafter, the reservoir 80 of the fuel gas supply manifold M1 may be read as the reservoir 80 of the oxidizing gas supply manifold M3, and the reservoir 80 of the fuel gas discharge manifold M2 may be read as the reservoir 80 of the oxidizing gas discharge manifold M4.

[0048] As in Fig. 4, the portion of the reservoir 80 of the fuel gas supply manifold M1 included in the power generation cell 20 is located below a lowermost part of the portion connecting the peripheral edge of the fuel gas supply manifold M1 to the fuel gas passage 51. Specifically, the reservoir 80 is located in the power generation cell 20 below the lowermost of the straight portions 53b of the supply-side connecting passage 53. In other words, the straight portions 53b of the supply-side connecting passage 53 are connected to the fuel gas supply manifold M1 at locations of the peripheral edge of the fuel gas supply manifold M1 above the reservoir 80.

[0049] The portion of the reservoir 80 of the fuel gas discharge manifold M2 included in the power generation cell 20 is located below a lowermost part of the portion connecting the peripheral edge of the fuel gas discharge manifold M2 to the fuel gas passage 51. Specifically, the reservoir 80 is located in the power generation cell 20 below the lowermost of the straight portions 54b of the discharge-side connecting passage 54. In other words, the straight portions 54b of the discharge-side connecting passage 54 are connected to the fuel gas discharge manifold M2 at locations of the peripheral edge of the fuel gas discharge manifold M2 above the reservoir 80.

[0050] As in Fig. As shown in Figure 7, the reservoir 80 has two side walls 81 facing each other in the Y-axis direction. The two side walls 81 are inclined relative to the Z-axis direction such that they approach each other toward the lower portion. The inclination angles α of the two side walls 81 relative to the Y-axis direction are equal to each other.

[0051] As in Fig. 8, the mobile unit 1 (see Fig. 1), while moving, for example, along a slope, may be inclined with respect to the horizontal direction. The inclination angle α of each of the two side walls 81 in the Y-axis direction is set greater than a maximum inclination angle αm. The maximum inclination angle αm is a maximum value of the inclination angle of the mobile unit 1 with respect to the horizontal direction, which is assumed during the movement of the mobile unit 1. The maximum inclination angle αm is, for example, between 15° and 30°.

[0052] The corners of the peripheral edges of the manifolds M1 to M6, which include the lower ends of the two side walls 81, have arcuate cross-sections orthogonal to the X-axis direction. By providing such an arcuate section, punching the separators 50, 60, 150 to form the through holes included in each of the manifolds M1 to M6 is easier than if the corners have a sharp-edged shape.

[0053] As in Fig. 6, the portion of the reservoir 80 of the fuel gas supply manifold M1 included in the dummy cell 20D is connected to the fuel gas passage 151 of the dummy cell 20D. Specifically, the portion of the reservoir 80 of the fuel gas supply manifold M1 included in the dummy cell 20D is connected to one or more straight portions 53b in the supply-side communication passage 53 of the dummy cell 20D. The straight portions 53b extend, for example, by branching from a single inclined portion 53a, and open in the reservoir 80. The straight portions 53b are located below the supply-side communication passage 53 of the power generation cell 20. The portion of the reservoir 80 of the fuel gas discharge manifold M2 included in the dummy cell 20D is not connected to the fuel gas passage 151 of the dummy cell 20D.Although not shown in the drawings, the portions of the reservoirs 80 of the oxidizing gas supply manifold M3 and the oxidizing gas discharge manifold M4 included in the dummy cell 20D are also not connected to the oxidizing gas passage of the dummy cell 20D.

[0054] The operation of the present embodiment will now be described.

[0055] The reservoir 80 of the fuel gas discharge manifold M2 is located below the lowermost part of the section connecting the peripheral edge of the fuel gas discharge manifold M2 to the fuel gas passage 51. This allows the water that has flowed into the fuel gas discharge manifold M2 to be easily stored in the reservoir 80. Furthermore, the cross-sectional area of ​​the reservoir 80 is partially reduced. Thus, the flow velocity of reactant gas flowing through the reservoir 80 is higher than the flow velocity in other sections of the fuel gas discharge manifold M2. The same applies to the oxidizing gas discharge manifold M4.

[0056] The advantages of the present embodiment will now be described.

[0057] (1) The lower portion of the peripheral edge of each of the fuel gas discharge manifold M2 and the oxidizing gas discharge manifold M4 includes the reservoir 80, which has a partially reduced cross-sectional area and stores the moisture contained in the reaction gas. The reservoir 80 of the fuel gas discharge manifold M2 is located below the lowermost part of the portion connecting the peripheral edge of the fuel gas discharge manifold to the fuel gas passage 51. The reservoir 80 of the oxidizing gas discharge manifold M4 is located below the lowermost part of the portion connecting the peripheral edge of the oxidizing gas discharge manifold M4 to the oxidizing gas passage 61.

[0058] This configuration produces the operation described above. This allows the water that has flowed into the fuel gas discharge manifold M2 and is stored in the reservoir 80 to easily flow through the fuel gas discharge manifold M2 along with the reactant gas. This limits a reduction in the flow area of ​​the fuel gas discharge manifold M2 caused by water accumulation. The same applies to the oxidizing gas discharge manifold M4.

[0059] (2) The lower portion of the peripheral edge of each of the fuel gas supply manifold M1 and the oxidizing gas supply manifold M3 includes the reservoir 80. The reservoir 80 of the fuel gas supply manifold M1 is located below the portion connecting the peripheral edge of the fuel gas supply manifold M1 to the fuel gas passage 51. The reservoir 80 of the oxidizing gas supply manifold M3 is located below the portion connecting the peripheral edge of the oxidizing gas supply manifold M3 to the oxidizing gas passage 61.

[0060] This configuration allows the water that has flowed into the fuel gas supply manifold M1 to be easily stored in the reservoir 80. Furthermore, the flow rate of reactant gas flowing through the reservoir 80 becomes greater than the flow rate in other portions of the fuel gas supply manifold M1. This allows the water that has flowed into the fuel gas supply manifold M1 and is stored in the reservoir 80 to easily flow through the fuel gas supply manifold M1 together with the reactant gas. This limits a reduction in the flow area of ​​the fuel gas supply manifold M1 caused by water accumulation. The same applies to the oxidizing gas supply manifold M3.

[0061] (3) The portion of the reservoir 80 of the fuel gas supply manifold M1 included in the dummy cell 20D is connected to the fuel gas passage 151 of the dummy cell 20D.

[0062] With this configuration, when water accumulates in the reservoir 80 of the fuel gas supply manifold M1, the water flows from the portion of the reservoir 80 contained in the dummy cell 20D to the fuel gas passage 151 of the dummy cell 20D. The water is then discharged to the outside from the fuel gas discharge manifold M2. This limits the inflow of water into the fuel gas passage 51 of the power generation cell 20 that generates power, while facilitating the inflow of water into the fuel gas passage 151 of the dummy cell 20D that does not generate power. Accordingly, a decrease in the power generation capacity of the fuel cell stack 11 is limited.

[0063] (4) The cross-sectional area of ​​the reservoir 80 gradually decreases towards the lower section.

[0064] In this configuration, the flow rate of the reaction gas flowing through the reservoir 80 increases toward the lower portion. Therefore, the smaller the amount of water stored in the reservoir 80, the greater the flow rate of the reaction gas flowing through the reservoir 80. This facilitates rapid flow of the water stored in the reservoir 80 through each of the manifolds M1 to M4 along with the reaction gas. Accordingly, the drainage performance of each of the manifolds M1 to M4 is increased.

[0065] (5) The two side walls 81 of the reservoir 80 are inclined with respect to the Z-axis direction so as to approach each other toward the lower portion.

[0066] This configuration allows the water adhering to the side walls 81 of the reservoir 80 to easily flow downward along the side walls 81. As it flows downward, the flow velocity of the reaction gas in the reservoir 80 increases. This allows the water that has flowed downward along the side walls 81 to easily flow through the manifolds M1 to M4 together with the reaction gas. Accordingly, the drainage performance of each of the manifolds M1 to M4 is further enhanced.

[0067] (6) The inclination angle α of each of the two side walls 81 of the reservoir 80 with respect to the horizontal direction is larger than the maximum inclination angle αm.

[0068] Even if the fuel cell stack 11 is tilted in this configuration due to a change in the orientation of the fuel cell stack 11 with respect to the horizontal direction when the mobile unit 1 is as shown in Fig. 8, the orientation in which the side walls 81 are inclined toward the reservoir 80 is maintained. This prevents the water stored in the reservoir 80 from flowing into the fuel gas passage 51 and the oxidizing gas passage 61. Variations

[0069] The present embodiment may be modified as follows. The present embodiment and the following modifications may be combined as long as they remain technically consistent with each other.

[0070] The angles of inclination α of the two side walls 81 of the reservoir 80 may differ from each other.

[0071] The inclination angle α of at least one of the two side walls 81 of the reservoir 80 may be smaller than the maximum inclination angle αm.

[0072] The fuel cell stack 11 does not have to be mounted on the mobile unit 1. For example, a stationary fuel cell stack 11 can be used as the fuel cell stack 11.

[0073] As in Fig. 9, one of the two side walls 81 of the reservoir 80 may extend in the Z-axis direction.

[0074] The sections of each of the manifolds M1 to M4 may have any shape except for the reservoir 80. For example, as shown in Fig. 10, the upper portion of the fuel gas discharge manifold M2 may have a cross-sectional area that decreases toward the upper portion. As shown in Fig. 11, the fuel gas discharge manifold M2 may alternatively have an asymmetric shape with respect to the Y-axis direction.

[0075] The cross-sectional area of ​​the reservoir 80 may gradually decrease toward the lower portion. In this case, the distance between the side walls 81 in the Y-axis direction must decrease gradually.

[0076] The reservoir 80 may be a groove provided on the bottom surface of the fuel gas discharge manifold M2. In this case, the cross-sectional area of ​​the reservoir 80 in the Z-axis direction may remain constant if it is smaller than the cross-sectional areas in other sections.

[0077] The fuel gas passage 151 of the dummy cell 20D may be connected to the bottom surface of the portion of the reservoir 80 contained in the dummy cell 20D.

[0078] The portion of the reservoir 80 of the fuel gas discharge manifold M2 contained in the dummy cell 20D can be connected to the fuel gas passage 151 of the dummy cell 20D.

[0079] The portion of the reservoir 80 of at least one of the oxidizing gas supply manifold M3 and the oxidizing gas discharge manifold M4 included in the dummy cell 20D may be connected to the oxidizing passage (not shown) of the dummy cell 20D.

[0080] The dummy cell 20D may be located between multiple power generation cells 20. This means that the dummy cell 20D may be held between the power generation cells 20.

[0081] The dummy cell 20D may be located at each of the opposite ends of the power generation cells 20 in the X-axis direction.

[0082] The fuel cell 11 does not need to contain the dummy cell 20D.

[0083] At least one of the fuel gas supply manifold M1 and the oxidizing gas supply manifold M3 need not include the reservoir 80.

[0084] The reservoir 80 may be included in only one of the fuel gas discharge manifold M2 and the oxidizer gas discharge manifold M4.

[0085] At least a part of each of the supply-side communication passages 53, 63 and the discharge-side communication passages 54, 64 may be a communication hole extending through the frame 40 and connected to one of the manifolds M1 to M4.

[0086] The X-axis direction, which is the stacking direction of the power generation cells 20, may be inclined with respect to the vertical and horizontal directions.

[0087] The modifications described above for the fuel gas delivery manifold M2 can also be used for the manifolds M1, M3, M4.

[0088] Various changes in form and details may be made to the above examples without departing from the spirit and scope of the claims and their equivalents. The examples are intended to be descriptive and not limiting. Descriptions of features in each example are deemed to be applicable to similar features or embodiments of the other examples. Suitable results may be achieved if sequences are performed in a different order and / or if components in a described system, architecture, device, or circuit are combined differently and / or are replaced or supplemented with other components or their equivalents. The scope of the disclosure is defined by the claims and their equivalents, not the detailed description. All changes within the scope of the claims and their equivalents are intended to be included within the disclosure. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2018 - 78 020 A

[0002]

Claims

[1] A fuel cell stack comprising power generation cells (20) stacked in a first direction intersecting a vertical direction, each of the power generation cells (20) having a power generation section (30) that generates power when supplied with reaction gas, the fuel cell stack further comprising: a gas passage (51, 61) facing the power generation section (30) and through which the reaction gas flows; and a gas supply manifold (M1, M3) and a gas discharge manifold (M2, M4) connected to the gas passage (51, 61), wherein the gas supply manifold (M1, M3) and the gas discharge manifold (M2, M4) are each located at a location aligned with the gas passage (51, 61) in a second direction and extend through the power generation cells (20) in the first direction, the second direction being orthogonal to the vertical direction and the first direction, a lower portion of a peripheral edge of the gas discharge manifold (M2, M4) has a reservoir (80) in which an area of a cross section orthogonal to the first direction is partially reduced, the reservoir (80) being configured to store moisture contained in the reaction gas, and the reservoir (80) is located in the vertical direction below a lowermost part of a section connecting the peripheral edge of the gas discharge manifold (M2, M4) to the gas passage (51, 61). [2] The fuel cell stack according to claim 1, wherein a lower portion of a peripheral edge of the gas supply manifold (M1, M3) has a reservoir (80) in which an area of a cross section orthogonal to the first direction is partially reduced, the reservoir (80) being configured to store moisture contained in the reaction gas, and the reservoir (80) of the gas supply manifold (M1, M3) is located below a portion connecting the peripheral edge of the gas supply manifold (M1, M3) to the gas passage (51, 61) in the vertical direction. [3] Fuel cell stack according to claim 2, wherein a flow direction of the reaction gas flowing through the gas supply manifold (M1, M3) is simply referred to as a flow direction, the fuel cell stack further comprises a dummy cell (20D) stacked on a downstream side of the power generation cells (20) in the flow direction, the dummy cell (20D) not generating power, the dummy cell (20D) has a gas passage (151) through which the reaction gas flows, the gas supply manifold (M1, M3) and the gas discharge manifold (M2, M4) extend through the dummy cell (20D) and are connected to the gas passage (151) of the dummy cell (20D) and a portion of the reservoir (80) of the gas supply manifold (M1, M3) contained in the dummy cell (20D) is connected to the gas passage (151) of the dummy cell (20D). [4] A fuel cell stack according to any one of claims 1 to 3, wherein the area of the reservoir (80) gradually decreases toward a lower portion in the vertical direction. [5] Fuel cell stack according to claim 4, wherein the reservoir (80) has two side walls (81) facing each other in the second direction, and the two side walls (81) are inclined with respect to the vertical direction such that the two side walls (81) approach each other towards the lower portion in the vertical direction. [6] Fuel cell stack according to claim 5, wherein the fuel cell stack is mounted on a mobile unit (1) in an orientation in which the second direction coincides with a direction of movement of the mobile unit (1), a maximum value of an inclination angle of the mobile unit (1) with respect to a horizontal direction, which is taken during a movement of the mobile unit (1), is referred to as a maximum inclination angle (αm) and an inclination angle (α) of each of the two side walls (81) with respect to the second direction is greater than the maximum inclination angle (αm).

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