fuel cell stack

Abstract

To provide a fuel cell stack that allows moisture to efficiently circulate.SOLUTION: A fuel cell stack 1 includes an electrolyte membrane-electrode structure 20 in which a solid polymer electrolyte membrane 21 is sandwiched between an anode electrode 22 and a cathode electrode 23, and is configured to generate power by an electrochemical reaction between an oxidant gas and a fuel gas. The fuel cell stack 1 includes: a cell 11 to which the oxidant gas and / or the fuel gas is supplied; an oxidant gas supply passage 31 for supplying the oxidant gas to the cell 11; an oxidant off-gas flow passage 32 through which the oxidant gas discharged from the cell 11 flows; and a communication passage 40 connecting the oxidant gas supply passage 31 and the oxidant off-gas flow passage 32. A pressure at a first opening 41 through which the communication passage 40 is connected to the oxidant gas supply passage 31 is lower than a pressure at a second opening 42 through which the communication passage 40 is connected to the oxidant off-gas flow passage 32.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In recent years, research and development into fuel cells has been conducted to contribute to energy efficiency, ensuring that more people have access to affordable, reliable, sustainable and advanced energy.

[0003] In a membrane electrode assembly in which a solid polymer electrolyte membrane is sandwiched between an anode and a cathode, power is generated by an electrochemical reaction between fuel gas supplied to the anode and oxidant gas supplied to the cathode. To achieve this, the electrolyte membrane must be kept humidified so that protons generated at the anode can move to the cathode, resulting in proton conduction. A known technique involves providing a humidifier in the oxidant gas supply channel. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-157281 Summary of the Invention [Problem to be solved by the invention]

[0005] The addition of a separate device, such as a humidifier, not only increased manufacturing costs, but also required dedicated space within the fuel cell stack, which increased power consumption. There was also a need for greater energy efficiency. [Means for solving the problem]

[0006] (1) The present invention provides a fuel cell stack (e.g., fuel cell stack 1) that includes a membrane electrode assembly (e.g., membrane electrode assembly 20) in which a solid polymer electrolyte membrane (e.g., solid polymer electrolyte membrane 21) is sandwiched between an anode electrode (e.g., anode electrode 22) and a cathode electrode (e.g., cathode electrode 23), and generates electricity by an electrochemical reaction between an oxidizer gas and a fuel gas. The fuel cell stack includes a cell (e.g., cell 11) to which an oxidizer gas and / or a fuel gas is supplied, and an oxidizer gas supply unit (e.g., cell 12) that supplies the oxidizer gas to the cell. The present invention relates to a fuel cell stack having a supply flow path (e.g., an oxidant gas supply flow path 31), an oxidant off-gas distribution flow path (e.g., an oxidant off-gas distribution flow path 32) through which oxidant gas discharged from the cell flows, and a communication path (e.g., a communication path 40) connecting the oxidant gas supply flow path and the oxidant off-gas distribution flow path, wherein the pressure at a first opening (e.g., a first opening 41) through which the communication path is connected to the oxidant gas supply flow path is lower than the pressure at a second opening (e.g., a second opening 42) through which the communication path is connected to the oxidant off-gas distribution flow path.

[0007] (2) Preferably, the diameter of the oxidizing gas supply channel at the position where the first opening is provided is smaller than the diameter of the oxidizing gas supply channel in the periphery of the first opening.

[0008] (3) The cells are stacked in multiple layers to form a stack (e.g., stack 10), and at the ends of the stack in the stacking direction, a terminal plate (e.g., terminal plate 15), an insulating plate (e.g., insulating plate 16), and an end plate (e.g., end plate 17) are provided in this order from the inside to the outside of the stack, and it is preferable that the communication path is formed between the terminal plate and the end plate.

[0009] (4) The communication passage is preferably formed inside the insulating plate. [Effects of the Invention]

[0010] According to the above (1), water vapor contained in the oxidant off-gas flow channel 32 is supplied from the second opening 42 of the communication channel 40 connected to the oxidant off-gas flow channel 32 to the first opening 41 of the communication channel 40 connected to the oxidant gas supply channel 31 via the communication channel 40, thereby circulating moisture and preventing the membrane electrode assembly 20 from drying out. Furthermore, since moisture such as water vapor circulates via the communication channel 40, the membrane electrode assembly 20 can be prevented from drying out without the need for additional devices such as a humidifier or hydrogen pump, thereby reducing manufacturing costs and power consumption, which in turn contributes to improved energy efficiency.

[0011] According to the above (2), the diameter D1 of the oxidant gas supply channel 31 at the position where the first opening 41 is provided is configured to be smaller than the diameter of the oxidant gas supply channel 31 in the periphery P of the first opening 41. This makes it possible to reduce the pressure of the first opening 41 on the oxidant gas supply channel 31 of the communication passage 40 with a simple configuration, and to circulate moisture efficiently.

[0012] According to the above (3), by arranging the communication passage 40 between the terminal plate 15 and the end plate 17 inside the fuel cell stack 1, the fuel cell stack 1 through which water circulates can be made smaller.

[0013] According to (4) above, the communication passage 40 can be easily formed without changing other components, and the same effect as that of steam can be achieved. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram of a fuel cell stack according to an embodiment of the present invention; [Figure 2] FIG. 2 is a diagram showing a power generating cell according to the present embodiment. [Figure 3] FIG. 2 is a view taken along the line A-A in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Fig. 1 is a diagram schematically illustrating the configuration of a fuel cell stack 1 of this embodiment. As shown in Fig. 1, the fuel cell stack 1 has a stack 10 formed by stacking a plurality of cells 11, and at the ends of the stack 10 in the stacking direction, a terminal plate 15, an insulating plate 16, and an end plate 17 are arranged in this order from the inside to the outside of the stack 10.

[0016] 1 and 2, the fuel cell stack 1 is configured to allow oxidant gas, fuel gas, and coolant to flow between the inside and outside of the cells 11. The fuel cell stack 1 has an oxidant gas supply passage 31, an oxidant off-gas flow passage 32, a communication passage 40, a fuel gas supply passage 33 (see FIG. 2 below), a fuel off-gas flow passage 34, a coolant supply passage 35, and a coolant discharge passage 36.

[0017] The cell 11 includes a power generating cell 12 and a dummy cell 14. Fig. 2 is a diagram illustrating the configuration of the power generating cell 12. As shown in Fig. 2, the power generating cell 12 includes a membrane electrode assembly 20, and a first metal separator 24 and a second metal separator 26 that sandwich the membrane electrode assembly 20. Although not shown, sealing members such as gaskets are interposed between the membrane electrode assembly 20 and the first metal separator 24 and second metal separator 26, covering the peripheries of various communication holes (described later) and the outer peripheries of the electrode surfaces (power generating surfaces).

[0018] At one end edge portion of the power generation cell 12 in the direction of arrow B, the following are arranged in the direction of arrow C (vertical direction), communicating with each other in the direction of arrow A, which is the stacking direction: an oxidant gas supply passage 31a for supplying an oxidant gas, for example, an oxygen-containing gas; a cooling medium discharge passage 36b for discharging a cooling medium; and a fuel gas discharge passage 34b for discharging a fuel gas, for example, a hydrogen-containing gas.

[0019] At the other end edge portion of the power generation cell 12 in the direction of arrow B, a fuel gas supply passage 33a for supplying fuel gas, a cooling medium supply passage 35a for supplying a cooling medium, and an oxidant gas discharge passage 32b for discharging oxidant gas are arranged in the direction of arrow C and are connected to each other in the direction of arrow A.

[0020] The oxidant gas supply passage 31a formed in each power generation cell 12 forms an oxidant gas supply channel 31 that supplies oxidant gas to the power generation cells 12 when the power generation cells 12 are stacked side by side as shown in Fig. 1. Furthermore, the oxidant gas discharge passage 32b forms an oxidant off-gas flow channel 32 through which oxidant gas discharged from the power generation cells 12 flows when the power generation cells 12 are stacked side by side as shown in Fig. 1. In order to show a communication channel 40 (described later), Fig. 1 schematically shows only the flow of oxidant gas in the oxidant gas supply channel 31 and the oxidant off-gas flow channel 32, and does not illustrate the fuel gas supply channel 33, the fuel off-gas flow channel 34, the coolant supply channel 35, and the coolant discharge channel 36.

[0021] The fuel gas supply passage 33a formed in each power generating cell 12 forms a fuel gas supply passage 33 that supplies fuel gas to the power generating cells 12 when the power generating cells 12 are stacked side by side. In addition, the fuel gas discharge passage 34b forms a fuel off-gas flow passage 34 through which fuel off-gas discharged from the power generating cells 12 flows when the power generating cells 12 are stacked side by side.

[0022] The coolant supply passages 35a formed in each power generating cell 12 form a coolant supply channel 35 that supplies a coolant to the first metal separator 24 and the second metal separator 26 (described later) when the power generating cells 12 are stacked side by side. The coolant discharge passages 36b form a coolant discharge channel 36 through which the coolant discharged from the first metal separator 24 and the second metal separator 26 (described later) flows.

[0023] The electrolyte membrane-electrode assembly 20 includes, for example, a solid polymer electrolyte membrane 21 in the form of a thin film of perfluorosulfonic acid impregnated with water, and an anode electrode 22 and a cathode electrode 23 that sandwich the solid polymer electrolyte membrane 21 (see FIGS. 1 and 2).

[0024] The anode 22 and the cathode 23 each have a gas diffusion layer made of carbon paper or the like, and an electrode catalyst layer in which porous carbon particles carrying a platinum alloy are uniformly applied to the surface of the gas diffusion layer. The electrode catalyst layers are bonded to both sides of the solid polymer electrolyte membrane 21 so as to face each other with the solid polymer electrolyte membrane 21 in between.

[0025] The first metal separator 24 and the second metal separator 26 are made of, for example, metal or carbon, and are arranged so as to sandwich the membrane electrode assembly 20 therebetween.

[0026] 2, the surface 24a of the first metal separator 24 facing the membrane electrode assembly 20 has oxidant gas flow grooves 25 that communicate with the oxidant gas supply passage 31a and the oxidant gas discharge passage 32b. The oxidant gas flow grooves 25 are formed on the surface 24a of the first metal separator 24, with multiple grooves extending in the direction of arrow B, allowing oxidant gas to flow between these grooves and the cathode 23. The oxidant gas flows through the oxidant gas flow grooves 25 in the direction of arrow B, and is supplied with oxidant gas from the oxidant gas supply passage 31 and discharged to the oxidant off-gas passage 32.

[0027] Fuel gas flow grooves 27 that communicate with the fuel gas supply passage 33a and the fuel gas discharge passage 34b are formed on the surface 26a of the second metal separator 26 facing the membrane electrode assembly 20. The fuel gas flow grooves 27 are formed on the surface 26a of the second metal separator 26 by forming a plurality of grooves extending in the direction of arrow B, and are formed so that fuel gas flows between these grooves and the anode 22. Fuel gas flows through the interior of the fuel gas flow grooves 27 in the direction of arrow B, and is supplied with fuel gas from the fuel gas supply passage 33 and discharged to the fuel off-gas passage 34.

[0028] 1 , a cooling medium flow groove 37 that communicates with the cooling medium supply passage 35a and the cooling medium discharge passage 36b is formed between the surface 24b of the first metal separator 24 and the surface 26b of the second metal separator 26, which are adjacent to each other. The cooling medium flow groove 37 extends in the direction of arrow B and is formed integrally by overlapping a plurality of grooves formed in the first metal separator 24 with a plurality of grooves formed in the second metal separator 26. The cooling medium flows through the cooling medium flow groove 37 in the direction of arrow B, receives the cooling medium from the cooling medium supply channel 35, and discharges it to the cooling medium discharge channel 36.

[0029] 1, the dummy cell 14 includes a conductive plate 52 corresponding to the membrane electrode assembly 20, and a dummy cell first metal separator 54 and a dummy cell second metal separator 56 that sandwich the conductive plate 52. The conductive plate 52 is made of, for example, a metal plate and is configured substantially identically to the membrane electrode assembly 20. However, the dummy cell 14 does not have the membrane electrode assembly 20 and does not generate water as a result of power generation.

[0030] The dummy cell first metal separator 54 and the dummy cell second metal separator 56 each have an oxidant gas supply passage 31a, a coolant discharge passage 36b, a fuel gas discharge passage 34b, a fuel gas supply passage 33a, a coolant supply passage 35a, and an oxidant gas discharge passage 32b. The oxidant gas supply passage 31a, the coolant discharge passage 36b, and the fuel gas discharge passage 34b are arranged in the direction of arrow C (vertical direction) at one end edge of the dummy cell first metal separator 54 and the dummy cell second metal separator 56 in the direction of arrow B. The fuel gas supply passage 33a, the coolant supply passage 35a, and the oxidant gas discharge passage 32b are arranged in the direction of arrow C at the other end edge of the dummy cell first metal separator 54 and the dummy cell second metal separator 56 in the direction of arrow B. The dummy cell 14 allows water vapor flowing into the oxidant gas supply flow path 31 to flow through multiple grooves extending in the direction of arrow B provided in the dummy cell first metal separator 54 and the dummy cell second metal separator 56, thereby preventing excessive water vapor from flowing into the power generation cell 12.

[0031] The terminal plates 15 are disposed at one end and the other end of the laminate 10 to sandwich the laminate 10. The terminal plates 15 are made of an electrically conductive material.

[0032] The insulating plates 16 are arranged side by side with the terminal plates 15 on the outer side in the stacking direction of the terminal plates 15. The insulating plates 16 are made of an insulating material such as polycarbonate or phenolic resin, and are formed thicker than the terminal plates 15 in the stacking direction as shown in FIG.

[0033] The end plates 17 are arranged on the outer sides of the insulating plates 16 in the stacking direction, alongside the insulating plates 16. The end plates 17 are positioned at the outermost positions of the fuel cell stack 1.

[0034] The terminal plate 15, insulating plate 16, and end plate 17 are respectively formed with the oxidant gas supply passage 31a, oxidant gas discharge passage 32b, coolant supply passage 35a, coolant discharge passage 36b, fuel gas discharge passage 34b, and fuel gas supply passage 33a, allowing oxidant gas, hydrogen gas, and coolant to be supplied to and discharged from the outside of the fuel cell stack 1. Therefore, the oxidant gas supply channel 31 and the oxidant off-gas flow channel 32 are formed penetrating the terminal plate 15, insulating plate 16, and end plate 17. As shown in FIG. 1 , the oxidant gas supply channel 31 penetrating the terminal plate 15, insulating plate 16, and end plate 17 is narrowed so that the inner diameter of the oxidant gas supply channel 31 is smaller than that within the stack 10. Note that the narrowing of the oxidant gas supply channel 31 corresponds to the inner diameter when the channel is configured to form a circular channel at its center, but the channel is not limited to being circular. When the flow path is not circular, the inner wall of the oxidizing gas supply flow path 31 narrows so that the distance between two opposing points is small.

[0035] 3 , the communication passage 40 is formed inside the insulating plate 16 to connect the oxidant gas supply channel 31 and the oxidant off-gas flow channel 32. Specifically, a pipe is provided connecting the oxidant gas supply passage 31a and the oxidant gas discharge passage 32b formed in the insulating plate 16, forming a space through which the oxidant gas can flow. Here, the oxidant gas supply passage 31a of the insulating plate 16 at the position where the communication passage 40 is connected is referred to as a first opening 41, and the oxidant gas discharge passage 32b of the insulating plate 16 at the position where the communication passage 40 is connected is referred to as a second opening 42. Therefore, the first opening 41 is an opening where the communication passage 40 is connected to the oxidant gas supply channel 31, and the second opening 42 is an opening where the communication passage 40 is connected to the oxidant off-gas flow channel 32.

[0036] As shown in FIG. 1 , the diameter D1 of the oxidant gas supply channel 31 at the position where the first opening 41 is provided is smaller than the diameter D2 of the periphery P of the oxidant gas supply channel 31 at the position where the first opening 41 is provided. If the first opening 41 is not circular, the distance between two opposing points on the first opening 41 is smaller than the distance between two opposing points on the second opening 42. That is, at the position where the first opening 41 is provided, the first opening 41 side narrows from the periphery P, making the oxidant gas supply channel 31 narrower. Therefore, due to the Venturi effect, the pressure at the first opening 41 is lower than the periphery P. Note that the "periphery P" may refer to a position away from the first opening 41 on the upstream or downstream side of the oxidant gas supply channel 31, as shown in FIG. 1 , for example, and may refer to a position close to the openings formed on the end plate 17 and terminal plate 15 sides. A certain portion passing through the first opening 41 between the downstream side of the end plate 17 and the upstream side of the terminal plate 15 may be continuously tapered. The diameter of this continuous thin portion may gradually increase toward the downstream side of the end plate 17 and the upstream side of the terminal plate 15 .

[0037] When comparing the pressure at the first opening 41 with the pressure at the second opening 42 connected to the oxidant off-gas flow passage 32 whose diameter is not narrowed, the pressure at the first opening 41 is lower than the pressure at the second opening 42.

[0038] The operation of the fuel cell stack 1 configured in this manner will be described below. As shown in FIG. 1, in a fuel cell stack 1, a fuel gas such as a hydrogen-containing gas, an oxidant gas which is an oxygen-containing gas such as air, and a cooling medium such as pure water, ethylene glycol, or oil are supplied to a stack 10 in which a plurality of power generation cells 12 and dummy cells 14 are stacked.

[0039] 2, in each power-generating cell 12, fuel gas is introduced through the fuel gas supply passage 33a into the fuel gas flow grooves 27 of the second metal separator 26 and flows along the anode 22 that constitutes the membrane electrode assembly 20. Meanwhile, oxidant gas is introduced through the oxidant gas supply passage 31a into the oxidant gas flow grooves 25 of the first metal separator 24 and flows along the cathode 23 that constitutes the membrane electrode assembly 20.

[0040] In the membrane electrode assembly 20, fuel gas supplied to the anode electrode 22 and oxidant gas supplied to the cathode electrode 23 are consumed in an electrochemical reaction within the electrode catalyst layer, generating electricity. In the catalyst layer of the anode electrode 22, electrons are removed from the hydrogen in the fuel gas to generate hydrogen ions, which then travel through the electrolyte membrane to the cathode side. Then, in the catalyst layer of the cathode electrode 23, the hydrogen ions react with oxygen in the oxidant gas to generate water. In this way, water is generated on the cathode side. A portion of the generated water travels through the electrolyte membrane to the anode side.

[0041] The oxidant gas supplied to and consumed by the cathode 23 is discharged along the oxidant gas discharge passage 32b in the direction of arrow A. The fuel gas supplied to and consumed by the anode 22 is discharged along the fuel gas discharge passage 34b in the direction of arrow A.

[0042] The cooling medium supplied to the cooling medium supply passage 35a is introduced into the cooling medium flow groove 37 between the first metal separator 24 and the second metal separator 26, and then flows in the direction of arrow B. After cooling the membrane electrode assembly 20, the cooling medium is discharged from the cooling medium discharge passage 36b.

[0043] The oxidant gas supply channel 31 and the oxidant off-gas flow channel 32 are connected by a communication channel 40. The pressure on the side of the first opening 41 connected to the oxidant gas supply channel 31 is lower than that on the side of the second opening 42 connected to the oxidant off-gas flow channel 32, forming a flow channel for the oxidant gas to flow from higher pressure to lower pressure. Therefore, downstream of the oxidant off-gas flow channel 32, part of the oxidant off-gas containing generated water is drawn from the second opening 42 to the first opening 41 through the communication channel 40. The part of the oxidant off-gas containing generated water mixes with newly supplied oxidant gas and merges into the oxidant gas supply channel 31. The water vapor changes into a mist-like form depending on the flow rate of the oxidant gas and flows through the oxidant gas supply channel 31. In this way, the oxidant gas containing a large amount of water vapor circulates between the communication channel 40, the oxidant gas supply channel 31, and the oxidant off-gas flow channel 32.

[0044] (1) According to this embodiment, the following effects are achieved. The fuel cell stack 1 includes a membrane electrode assembly 20 in which a solid polymer electrolyte membrane 21 is sandwiched between an anode electrode 22 and a cathode electrode 23, and is configured to generate power by an electrochemical reaction between an oxidant gas and a fuel gas. The fuel cell stack 1 includes cells 11 to which an oxidant gas and / or a fuel gas is supplied, an oxidant gas supply passage 31 that supplies an oxidant gas to the cells 11, an oxidant off-gas distribution passage 32 through which the oxidant gas discharged from the cells 11 flows, and a communication passage 40 that connects the oxidant gas supply passage 31 and the oxidant off-gas distribution passage 32. The pressure at a first opening 41 through which the communication passage 40 is connected to the oxidant gas supply passage 31 is set lower than the pressure at a second opening 42 through which the communication passage 40 is connected to the oxidant off-gas distribution passage 32. Water vapor contained in the oxidant off-gas flow channel 32 is supplied from the second opening 42 of the communication channel 40 connected to the oxidant off-gas flow channel 32 to the first opening 41 of the communication channel 40 connected to the oxidant gas supply channel 31 via the communication channel 40, thereby circulating moisture and preventing the membrane electrode assembly 20 from drying out. Furthermore, since moisture such as water vapor circulates via the communication channel 40, the membrane electrode assembly 20 can be prevented from drying out without the need for additional devices such as a humidifier or hydrogen pump, thereby reducing manufacturing costs and power consumption, which in turn contributes to improved energy efficiency.

[0045] (2) According to this embodiment, the diameter D1 of the oxidant gas supply channel 31 at the position where the first opening 41 is provided is configured to be smaller than the diameter of the oxidant gas supply channel 31 in the periphery P of the first opening 41. This makes it possible to reduce the pressure of the first opening 41 on the oxidant gas supply channel 31 of the communicating passage 40 with a simple configuration, thereby enabling efficient circulation of moisture.

[0046] (3) According to this embodiment, a stack 10 is formed by stacking a plurality of cells 11, and a terminal plate 15, an insulating plate 16, and an end plate 17 are provided at the ends of the stack 10 in the stacking direction, in this order from the inside to the outside of the stack 10. A communication path 40 is formed between the terminal plate 15 and the end plate 17. By arranging the communication path 40 between the terminal plate 15 and the end plate 17 within the fuel cell stack 1, the fuel cell stack 1, through which water circulates, can be made smaller.

[0047] (4) According to this embodiment, the communication passage 40 is formed inside the insulating plate 16. This allows the communication passage 40 to be easily formed without changing other components, and provides the same effect as steam.

[0048] In the embodiment described above, both the oxidant gas and the fuel gas are supplied to the power generating cell 12, and both the oxidant gas and the fuel gas are supplied to the dummy cell 14. However, the dummy cell 14 may be configured to be supplied with only one of the gases.

[0049] Furthermore, in the embodiment described above, the communicating passage 40 is disposed inside the insulating plate 16, but the location of the communicating passage 40 is not limited to inside the insulating plate 16. The communicating passage 40 only needs to be formed between the terminal plate and the end plate in the stacking direction, and may be formed within the terminal plate or the end plate, or may be formed across multiple plates. [Explanation of symbols]

[0050] 1. Fuel cell stack 10 Laminate 11 cells 15 Terminal plate 16 Insulation plate 17 End Plate 20 Electrolyte membrane / electrode structure 21 Solid polymer electrolyte membrane 22 Anode electrode 23 Cathode electrode 31 Oxidant gas supply channel 32 Oxidant off-gas flow path 40 Communication path 41 First opening 42 Second opening

Claims

1. A fuel cell stack comprising a membrane electrode assembly in which a solid polymer electrolyte membrane is sandwiched between an anode electrode and a cathode electrode, and which generates electricity through an electrochemical reaction between an oxidant gas and a fuel gas, The fuel cell stack comprises: a cell to which an oxidant gas and / or a fuel gas is supplied; an oxidant gas supply channel for supplying an oxidant gas to the cell; an oxidant off-gas flow passage through which the oxidant gas discharged from the cell flows; a communication passage connecting the oxidant gas supply passage and the oxidant off-gas flow passage, a pressure at a first opening, through which the communication passage is connected to the oxidant gas supply channel, being lower than a pressure at a second opening, through which the communication passage is connected to the oxidant off-gas distribution channel;

2. 2. The fuel cell stack according to claim 1, wherein a diameter of the oxidizing gas supply channel at a position where the first opening is provided is smaller than a diameter of the oxidizing gas supply channel in a periphery of the first opening.

3. a plurality of the cells are stacked to form a stack; a terminal plate, an insulating plate, and an end plate are provided at the end of the stack in the stacking direction from the inside to the outside of the stack, in this order; 3. The fuel cell stack according to claim 1, wherein the communication passage is formed between the terminal plate and the end plate.

4. The fuel cell stack according to claim 3 , wherein the communication passage is formed inside the insulating plate.

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