fuel cell stack

Abstract

To provide a fuel cell stack capable of smoothly draining liquid water which is generated by condensation of water vapor in a gas manifold.SOLUTION: In a fuel cell stack 11, a plurality of power generation cells 12 each generating power using a fuel gas is stacked in a vertical direction Z. Each power generation cell 12 comprises a support frame 19 supporting a membrane electrode assembly 18 and a pair of separators 20 holding the support frame 19 therebetween. A fuel gas supply hole 21 forming a fuel gas supply passage 28 which extends in the vertical direction Z and in which the fuel gas flows is formed in each generation cell 12. A projection 34 where water deposited to a bottom face 33, which is an upper wall surface of the fuel gas supply passage 28, is formed in a part of the bottom face 33. A cylindrical discharge path forming member 50 forming a discharge path 51, which discharges water dripped from the projection 34, and extending in the vertical direction Z is disposed at a lower side of the projection 34 in the fuel gas supply passage 28.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Conventionally, a known fuel cell stack is shown in Patent Document 1, for example. Such a fuel cell stack is formed by horizontally stacking a plurality of rectangular plate-shaped power generation cells. Each power generation cell includes a resin-framed membrane electrode assembly, and a first metal separator and a second metal separator that sandwich the resin-framed membrane electrode assembly. The membrane electrode assembly includes a solid polymer electrolyte membrane, and an anode electrode and a cathode electrode that sandwich the solid polymer electrolyte membrane.

[0003] The fuel cell stack is formed with a horizontally extending gas manifold and a horizontally extending drain (passage) below the gas manifold, penetrating each power-generating cell. The gas manifold and the drain are connected to each other at one end in the horizontal direction. The drain discharges water generated during operation of the fuel cell stack. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-121562 Summary of the Invention [Problem to be solved by the invention]

[0005] In the fuel cell stack described above, the gas manifold and drain extend horizontally and communicate with each other at one end, and the gas manifold is located above the drain. Therefore, even when the fuel cell stack is operating and the temperature rises, very little water vapor contained in the gas in the gas manifold flows into the drain.

[0006] On the other hand, when the fuel cell stack is shut down and the temperature drops, water vapor condenses in the gas manifold, generating liquid water in the gas manifold. In cold regions, liquid water can flow into piping connected to the gas manifold and freeze, potentially causing malfunctions in valves and other components in the piping. Therefore, it is desirable to be able to discharge liquid water generated by condensation of water vapor in the gas manifold. [Means for solving the problem]

[0007] The means for solving the above problems and their effects will be described below. The fuel cell stack that solves the above problem is a fuel cell stack in which a plurality of power generation cells that generate electricity using gas are stacked in the vertical direction, and the power generation cells include a support frame that supports a membrane electrode assembly and a pair of separators that sandwich the support frame, and the power generation cells are formed with gas holes that extend in the vertical direction and form gas manifolds through which the gas flows, and a water collection section is provided on a part of the upper wall surface of the gas manifold to collect water that adheres to the upper wall surface, and a vertically extending cylindrical discharge path forming member is arranged below the water collection section in the gas manifold to form a discharge path for discharging the water that falls from the water collection section.

[0008] Typically, when the temperature of the fuel cell stack is high, some of the water vapor present in the gas manifold condenses into liquid water and adheres to the upper wall surface of the gas manifold when the temperature of the fuel cell stack drops. The liquid water that adheres to the upper wall surface falls and accumulates in the piping connected to the gas manifold. When the fuel cell stack is used in a cold region or other location where the temperature drops below freezing, the liquid water that accumulates in the piping connected to the gas manifold freezes, causing problems such as clogging of the piping. In this regard, with the above-mentioned configuration, the liquid water that adheres to the upper wall surface of the gas manifold collects in the water collection section and then falls into the discharge path forming member to be discharged. Therefore, the liquid water generated by the condensation of water vapor in the gas manifold can be smoothly discharged. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is an end view of an embodiment of a fuel cell stack. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] Enlarged view of the main part of Figure 1. [Figure 5] FIG. 10 is an enlarged cross-sectional view of a main part of a fuel cell stack according to a modified example. [Figure 6] FIG. 10 is an enlarged cross-sectional view of a main portion of a fuel cell stack according to another modified example. [Figure 7] FIG. 10 is an enlarged cross-sectional view of a main portion of a fuel cell stack according to still another modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of a fuel cell stack will now be described with reference to the drawings. <Fuel cell stack 11> 1, the fuel cell stack 11 includes a cell stack 14 in which a plurality of rectangular plate-shaped power generating cells 12 that generate electricity using a fuel gas containing hydrogen and an oxidant gas containing oxygen, and one rectangular plate-shaped dummy cell 13 that does not generate electricity, are stacked in the thickness direction. The plurality of power generating cells 12 and the one dummy cell 13 are stacked in the vertical direction Z.

[0011] The dummy cell 13 is stacked on the power-generating cell 12 located at the upper end of the stacked plurality of power-generating cells 12. In other words, the dummy cell 13 is located at the upper end of the cell stack 14. End plates 17 are arranged on the upper and lower ends of the cell stack 14, with terminal plates 15 for current collection and insulating plates 16 for insulation therebetween.

[0012] <Power generation cell 12> 1 and 2, each power generating cell 12 has a frame-shaped support frame 19 made of synthetic resin that supports a rectangular sheet-shaped membrane electrode assembly (MEA) 18 at its central opening, and a pair of metal separators 20. The pair of separators 20 sandwich the membrane electrode assembly 18 and the support frame 19 in the vertical direction Z.

[0013] When fuel gas is supplied to one side (anode side) of the membrane electrode assembly 18 in the vertical direction Z and oxidant gas is supplied to the other side (cathode side) of the membrane electrode assembly 18, each power generating cell 12 generates electricity based on an electrochemical reaction between the fuel gas and the oxidant gas in the membrane electrode assembly 18. A plurality of (six in this example) holes are formed through both longitudinal ends of each power generating cell 12, i.e., both longitudinal ends of each support frame 19 and each separator 20.

[0014] These six holes are taken as an example of gas holes, that is, a fuel gas inlet 21, a fuel gas outlet 23, an oxidant gas inlet 24, an oxidant gas outlet 25, a coolant inlet 26, and a coolant outlet 27. The fuel gas inlet 21 has a width in the longitudinal direction of the power generation cell 12 that is wider than the other holes in the power generation cell 12. The fuel gas inlet 21 of the plurality of power generation cells 12 extends in the vertical direction Z to form a fuel gas supply passage 28 as an example of a gas manifold to which fuel gas as an example of a gas is supplied.

[0015] The fuel gas discharge holes 23 of the plurality of power generation cells 12 extend in the vertical direction Z to form a fuel gas discharge passage 30 through which the fuel gas is discharged. The oxidant gas supply holes 24 of the plurality of power generation cells 12 extend in the vertical direction Z to form an oxidant gas supply passage (not shown) through which the oxidant gas is supplied. The oxidant gas discharge holes 25 of the plurality of power generation cells 12 extend in the vertical direction Z to form an oxidant gas discharge passage (not shown) through which the oxidant gas is discharged.

[0016] The coolant supply holes 26 of the plurality of power generating cells 12 extend in the vertical direction Z and form a coolant supply passage (not shown) through which a coolant such as cooling water is supplied. The coolant discharge holes 27 of the plurality of power generating cells 12 extend in the vertical direction Z and form a coolant discharge passage (not shown) through which the coolant is discharged. The fuel gas discharge passage 30, the oxidant gas supply passage (not shown), the oxidant gas discharge passage (not shown), the coolant supply passage (not shown), and the coolant discharge passage (not shown) have a narrower width in the longitudinal direction of the power generating cells 12 than the fuel gas supply passage 28.

[0017] <Dummy cell 13> 1 and 3, the dummy cell 13 is the power-generating cell 12 in which the membrane electrode assembly 18 is replaced with a rectangular sheet-shaped conductor 31 and the upper separator 20 is replaced with a dummy separator 20a. The dummy cell 13 shares the lower separator 20 with the power-generating cell 12. That is, the dummy cell 13 has a support frame 19 supporting the conductor 31 in a central opening, a dummy separator 20a, and a separator 20. The support frame 19 supporting the conductor 31 in the dummy cell 13 is sandwiched between the dummy separator 20a and the separator 20 in the vertical direction Z.

[0018] The dummy separator 20a is the separator 20 of the power generation cell 12 without the fuel gas supply hole 21 and with a protrusion 34 on a part of the bottom surface 33, but otherwise has the same configuration as the separator 20. The dummy cell 13 does not have a membrane electrode assembly 18, so it does not generate electricity even when fuel gas and oxidant gas are supplied. The bottom surface 33 of the dummy separator 20a forms the upper wall surface of the fuel gas supply channel 28.

[0019] <Protrusion 34 and Discharge Path Forming Member 50> The protrusion 34 forms a water collecting section where water adhering to the lower surface 33 collects. The protrusion 34 is provided on part of the lower surface 33 of the dummy separator 20a in the fuel gas supply channel 28. A cylindrical discharge path forming member 50 extending in the vertical direction Z over almost the entire fuel gas supply channel 28 is disposed at the end of the fuel gas supply channel 28 opposite the membrane electrode assembly 18 side. The discharge path forming member 50 is fixed to the inside of the fuel gas supply channel 28 by a fixing portion (not shown).

[0020] The discharge path forming member 50 is disposed below the convex portion 34 in the fuel gas supply passage 28. The discharge path forming member 50 forms a discharge path 51 therein for discharging water that drops from the convex portion 34. The convex portion 34 has a triangular cross section and has an inclined surface 35 that decreases in height toward the discharge path forming member 50. The lowest part of the inclined surface 35 corresponds to the discharge path 51 in the vertical direction Z. The highest part of the inclined surface 35 is located at the end of the fuel gas supply passage 28 on the membrane electrode assembly 18 side. A small gap is formed between the upper end of the discharge path forming member 50 and the lower end of the convex portion 34.

[0021] <Connection structure between fuel cell stack 11 and piping> As shown in FIG. 1, in the fuel cell stack 11, the gaps between the terminal plate 15 and the separator 20, between the support frame 19 and the separator 20, between the support frame 19 and the dummy separator 20a, and between the separators 20 themselves are sealed by gaskets 36.

[0022] A fuel gas supply port 37 and a fuel gas discharge port 38 are formed through the terminal plate 15, insulating plate 16, and end plate 17 located at the lower end of the fuel cell stack 11. The lower end of a discharge path forming member 50 is inserted into a part of the fuel gas supply port 37. The fuel gas supply port 37 and the fuel gas discharge port 38 are connected to the fuel gas supply passage 28 and the fuel gas discharge passage 30, respectively.

[0023] A gas supply pipe 41 extending from a gas tank 40 containing fuel gas is connected to the fuel gas supply port 37. A pressure regulating valve 42 is provided midway along the gas supply pipe 41 to adjust the pressure of the fuel gas supplied from the gas tank 40 to the fuel gas supply port 37 via the gas supply pipe 41.

[0024] The upper end of a first discharge pipe 43 extending in the vertical direction Z is connected to the fuel gas discharge port 38. Unreacted fuel gas containing moisture is discharged from the fuel gas discharge port 38 to the first discharge pipe 43. A gas-liquid separator 44 that separates moisture from the unreacted fuel gas discharged from the fuel gas discharge port 38, and a first on-off valve 45 are provided midway along the first discharge pipe 43.

[0025] The first on-off valve 45 is disposed in the first discharge pipe 43 at a position below the gas-liquid separator 44. The first on-off valve 45 is normally closed, and is opened when discharging water separated from unreacted fuel gas in the gas-liquid separator 44. A connecting pipe 46 extending horizontally connects the side of the gas-liquid separator 44 to a position in the gas supply pipe 41 between the pressure adjustment valve 42 and the fuel gas supply port 37.

[0026] A pump 47 is provided midway along the connecting pipe 46, and sends the unreacted fuel gas from which water has been separated in the gas-liquid separator 44 toward the gas supply pipe 41. The upper end of a second discharge pipe 48 extending in the vertical direction Z is connected to the lower end of the discharge path forming member 50. A discharge path 51 in the discharge path forming member 50 communicates with the inside of the second discharge pipe 48. A second opening / closing valve 49 is provided midway along the second discharge pipe 48. The second opening / closing valve 49 is normally closed, and opens when water accumulated in the discharge path 51 and the second discharge pipe 48 is to be discharged.

[0027] An oxidant gas supply port (not shown) and an oxidant gas discharge port (not shown) are formed through the terminal plate 15, insulating plate 16, and end plate 17 located at the lower end of the fuel cell stack 11. The oxidant gas supply port and the oxidant gas discharge port are connected to the oxidant gas supply passage (not shown) and the oxidant gas discharge passage (not shown), respectively. The oxidant gas supply port and the oxidant gas discharge port are connected to pipes (not shown), respectively.

[0028] A cooling medium supply port (not shown) and a cooling medium discharge port (not shown) are formed through the terminal plate 15, insulating plate 16, and end plate 17 located at the lower end of the fuel cell stack 11. These cooling medium supply port and cooling medium discharge port are connected to the cooling medium supply passage (not shown) and the cooling medium discharge passage (not shown), respectively. Pipes (not shown) are connected to the cooling medium supply port and the cooling medium discharge port, respectively.

[0029] <Function of fuel cell stack 11> 1 and 4, when power generation is performed in the fuel cell stack 11, fuel gas from a gas tank 40 is supplied to the fuel gas supply passage 28 via a gas supply pipe 41 and a fuel gas supply port 37. In this case, the pressure of the fuel gas supplied to the fuel gas supply passage 28 is adjusted by a pressure adjustment valve 42. The fuel gas supplied to the fuel gas supply passage 28 is supplied to the anode side surface of the membrane electrode assembly 18 of each power generation cell 12 located below the dummy cell 13.

[0030] Meanwhile, an oxidant gas is supplied from an oxidant gas supply port (not shown) through an oxidant gas supply passage (not shown) to the cathode side surface of the membrane electrode assembly 18 of each power generation cell 12. Then, power is generated based on an electrochemical reaction in the membrane electrode assembly 18 between the oxidant gas supplied to the cathode side surface of the membrane electrode assembly 18 of each power generation cell 12 and the fuel gas supplied to the anode side surface of the membrane electrode assembly 18 of each power generation cell 12.

[0031] The unreacted fuel gas in the membrane electrode assembly 18 contains moisture and is discharged to the first discharge pipe 43 via the fuel gas discharge passage 30 and the fuel gas discharge port 38. The moisture-containing unreacted fuel gas discharged to the first discharge pipe 43 is separated from the moisture in the gas-liquid separator 44, and then sent by the pump 47 through the connecting pipe 46 to the gas supply pipe 41. The unreacted fuel gas sent to the gas supply pipe 41 is supplied again to the fuel gas supply passage 28 together with the fuel gas from the gas tank 40. The unreacted oxidant gas in the membrane electrode assembly 18 is discharged from the oxidant gas supply port (not shown) via an oxidant gas discharge passage (not shown).

[0032] Furthermore, since the temperature of the fuel cell stack 11 is high during operation of the fuel cell stack 11, the moisture in the fuel cell stack 11 turns into water vapor. In particular, the fuel gas supplied to the fuel gas supply passage 28 contains water, so water vapor exists in the fuel gas supply passage 28. In this case, since the upper end opening of the discharge path forming member 50 is open, some of the water vapor in the fuel gas supply passage 28 flows from the upper end opening of the discharge path forming member 50 into the discharge path 51.

[0033] When the operation of the fuel cell stack 11 is stopped, the temperature of the fuel cell stack 11 drops, causing the water vapor in the discharge path 51 and the water vapor in the fuel gas supply passage 28 to condense into liquid water W. At this time, the water vapor in the fuel gas supply passage 28 tends to accumulate at the upper end of the fuel gas supply passage 28, and so condenses into liquid water W while adhering to the lower surface 33 and inclined surface 35 of the dummy separator 20a.

[0034] Then, the liquid water W flows due to gravity down the inclined surface 35 toward the discharge path forming member 50 and drips (falls) into the discharge path 51. As a result, the liquid water W generated by condensation of water vapor in the fuel gas supply path 28 is smoothly discharged through the discharge path 51. Therefore, the amount of liquid water W dripping from the lower surface 33 of the dummy separator 20a to the outside of the discharge path forming member 50 in the fuel gas supply path 28 is reduced.

[0035] Incidentally, if the discharge path forming member 50 (discharge path 51) is not present in the fuel cell stack 11, a large amount of liquid water W is generated due to condensation of water vapor in the fuel gas supply path 28. Then, this liquid water W flows by gravity from the fuel gas supply path 28 through the fuel gas supply port 37 into the gas supply pipe 41.

[0036] Therefore, when the fuel cell stack 11 is used in a cold region or other place where the temperature drops below freezing, the liquid water W that flows into the gas supply pipe 41 freezes, causing clogging of the gas supply pipe 41 and freezing of the pressure adjustment valve 42. As a result, it becomes difficult for fuel gas to be supplied from the gas tank 40 to the fuel gas supply passage 28, which causes a problem of difficulty in starting the fuel cell stack 11.

[0037] In this regard, in the fuel cell stack 11 of this embodiment, as described above, the liquid water W generated by condensation of water vapor in the fuel gas supply passage 28 is smoothly discharged through the discharge path 51. Therefore, when the temperature drops due to the shutdown of the fuel cell stack 11, the amount of liquid water W present in the fuel gas supply passage 28 is reduced, and the amount of liquid water W that flows by gravity from the fuel gas supply passage 28 through the fuel gas supply port 37 into the gas supply piping 41 is also reduced.

[0038] As a result, even when the fuel cell stack 11 is used in a cold region or other place where the temperature drops below freezing, clogging of the gas supply pipe 41 and freezing of the pressure adjustment valve 42 due to freezing of the liquid water W are suppressed, thereby improving the startability of the fuel cell stack 11 in a cold region or other place where the temperature drops below freezing.

[0039] Furthermore, the liquid water W accumulated in the discharge path 51 can be smoothly discharged to the outside through the second discharge pipe 48 by opening the second opening / closing valve 49 when the temperature in the place where the fuel cell stack 11 is used is at a temperature at which the liquid water W will not freeze.

[0040] <Effects of the embodiment> According to the embodiment described above in detail, the following effects are achieved. (1) The fuel cell stack 11 includes a plurality of power generation cells 12 that generate power using fuel gas, stacked in the vertical direction Z. Each power generation cell 12 includes a support frame 19 that supports a membrane electrode assembly 18, and a pair of separators 20 that sandwich the support frame 19. Each power generation cell 12 is formed with a fuel gas supply hole 21 that extends in the vertical direction Z and forms a fuel gas supply channel 28 through which fuel gas flows. A protrusion 34 is provided on a portion of the lower surface 33 of the dummy separator 20a, which forms the upper wall surface of the fuel gas supply channel 28, and collects water that adheres to the lower surface 33. The protrusion 34 has an inclined surface 35 that decreases in height toward the discharge channel forming member 50. A cylindrical discharge channel forming member 50 that extends in the vertical direction Z and forms a discharge channel 51 that discharges liquid water W that drips (falls) from the protrusion 34 is disposed below the protrusion 34 in the fuel gas supply channel 28.

[0041] Typically, when the temperature of the fuel cell stack 11 is high, some of the water vapor present in the fuel gas supply passage 28 condenses into liquid water W and adheres to the lower surface 33 of the fuel gas supply passage 28 as the temperature of the fuel cell stack 11 drops. The liquid water W that adheres to the lower surface 33 of the fuel gas supply passage 28 drops and accumulates in the gas supply pipe 41 connected to the fuel gas supply passage 28. If the fuel cell stack 11 is used in a cold region or other location where the temperature drops below freezing, the liquid water W that accumulates in the gas supply pipe 41 freezes, causing problems such as clogging of the gas supply pipe 41. In this regard, with the above-described configuration, the liquid water W that adheres to the lower surface 33 of the fuel gas supply passage 28 flows by gravity along the inclined surface 35 of the convex portion 34 toward the discharge path forming member 50 and then drops into the discharge path 51 within the discharge path forming member 50 to be discharged. Therefore, the liquid water W that is generated by the condensation of water vapor within the fuel gas supply passage 28 can be smoothly discharged.

[0042] (Example of change) The above embodiment can be modified as follows: Furthermore, the above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0043] 5, an expanded diameter portion 52 that increases the diameter of the discharge path 51 in the discharge path forming member 50 may be provided at the upper end of the discharge path forming member 50. In this way, the liquid water W dripping from the convex portion 34 can be prevented from spilling out of the discharge path 51.

[0044] 6, the lower end of the protrusion 34 may be inserted into the discharge path 51 from the upper end opening of the discharge path forming member 50. In this way, the liquid water W dripping from the protrusion 34 can be further prevented from spilling out of the discharge path 51.

[0045] As shown in FIG. 7 , the lower surface 33 of the fuel gas supply passage 28 may be provided with a hydrophilic portion 53, an example of a water collecting portion, instead of the protrusion 34. That is, the water collecting portion may be formed by the hydrophilic portion 53. The hydrophilic portion 53 is a portion of the lower surface 33 that is more hydrophilic than the remaining portions of the lower surface 33. Specifically, the hydrophilicity of the material of the portion of the lower surface 33 that constitutes the hydrophilic portion 53 may be higher than the hydrophilicity of the material of the remaining portions of the lower surface 33. Alternatively, the hydrophilic portion 53 may be formed by applying a coating material to a portion of the lower surface 33 that has a higher hydrophilicity than the material of the dummy separator 20a. In this way, when water vapor adheres to the portions of the lower surface 33 other than the hydrophilic portion 53 and condenses to form liquid water W, the liquid water W can easily flow into the hydrophilic portion 53. Note that the portions of the lower surface 33 other than the hydrophilic portion 53 may be made water-repellent.

[0046] The protrusions 34 may be formed integrally with the lower surface 33 of the dummy separator 20a, or may be formed separately from the dummy separator 20a and attached to the lower surface 33 of the dummy separator 20a.

[0047] The protrusions 34 may be formed in a conical or pyramidal shape. In the power generating cell 12, the fuel gas supply hole 21 may be changed to any shape. The inner and outer diameters of the discharge path forming member 50 may be changed as appropriate. The cross-sectional shape of the discharge path forming member 50 is not limited to a circle, and may be, for example, an ellipse or a polygon.

[0048] In the fuel cell stack 11, the gas is an oxidant gas, the gas holes are oxidant gas inlets 24, and the gas manifold is an oxidant gas supply passage (not shown) that extends in the vertical direction Z and supplies the oxidant gas. A protrusion 34 may be provided on the upper wall surface of the oxidant gas supply passage, and a discharge path forming member 50 may be disposed below the protrusion 34 within the oxidant gas supply passage. In other words, the protrusion 34 and the discharge path forming member 50 may be applied to the oxidant gas inlets 24 as a gas manifold. Alternatively, the protrusion 34 and the discharge path forming member 50 may be applied to the fuel gas discharge passage 30 or the oxidant gas discharge passage (not shown) as a gas manifold.

[0049] In the fuel cell stack 11, the dummy cell 13 may be omitted, and the lower surface of the upper terminal plate 15 may serve as the upper wall surface of the fuel gas supply passage 28 (gas manifold) instead of the lower surface 33 of the dummy separator 20a. In this case, the protrusion 34 is provided on the lower surface of the upper terminal plate 15.

[0050] The fuel cell stack 11 may be used in a fuel cell system installed in an electric vehicle or a hybrid vehicle, or may be used in a stationary fuel cell system installed outdoors. [Explanation of symbols]

[0051] 11...Fuel cell stack 12...Power generation cell 13...Dummy cell 14...Cell stack 15...Terminal plate 16...Insulating plate 17...End plate 18...Membrane electrode assembly 19...Support frame 20...Separator 20a...Dummy separator 21...Fuel gas supply hole as an example of a gas hole 23...Fuel gas exhaust hole 24...Oxidant gas supply hole 25...Oxidant gas exhaust hole 26…Cooling medium supply hole 27…Cooling medium discharge hole 28...Fuel gas supply passage as an example of a gas manifold 30...Fuel gas discharge passage 31...Conductor 33... Lower surface as an example of upper wall surface 34...Convex portion as an example of a water collecting portion 35…Slope surface 36...Gasket 37...Fuel gas supply port 38...Fuel gas outlet 40...Gas tank 41...Gas supply pipe 42...Pressure regulating valve 43...1st discharge piping 44…Gas-liquid separator 45...First shut-off valve 46…Connecting pipe 47...Pump 48…Second discharge piping 49...Second shut-off valve 50...Discharge path forming member 51...Discharge path 52... Expanded diameter part 53...Hydrophilic area as an example of a water collection area W…Liquid water (water) Z: Vertical direction

Claims

1. A fuel cell stack in which a plurality of power generation cells that generate electricity using gas are stacked vertically, the power-generating cell includes a support frame that supports a membrane electrode assembly, and a pair of separators that sandwich the support frame; The power generation cell is formed with gas holes that extend in a vertical direction and form a gas manifold through which the gas flows, a water collecting portion for collecting water adhering to the upper wall surface of the gas manifold is provided on a part of the upper wall surface of the gas manifold; A fuel cell stack characterized in that a vertically extending cylindrical discharge path forming member is disposed below the water collection portion of the gas manifold, forming a discharge path for discharging the water falling from the water collection portion.

2. 2. The fuel cell stack according to claim 1, wherein the water collecting portion has an inclined surface whose height decreases toward the discharge path forming member.

3. 2. The fuel cell stack according to claim 1, wherein the water collecting portion is formed of a hydrophilic portion that has higher hydrophilicity than the remaining portion of the upper wall surface.

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