Fuel cell stack

Abstract

A fuel cell stack is provided with: a cell stack in which a gas supply flow path and a gas discharge flow path are respectively provided so as to extend in a prescribed direction, and in which a gas flow path that connects the gas supply flow path and the gas discharge flow path is provided; a first end unit provided with a supply port communicating with the gas supply flow path and a discharge port communicating with the gas discharge flow path; a second end unit; and a pipe body that is disposed in the gas supply flow path, extends in a predetermined direction, and is provided with a first opening and a second opening, which communicate with the upstream side and the downstream side of the gas supply flow path, on one end side and the other end side, respectively. In the fuel cell stack, a drain channel for guiding the liquid water flowing out from the second opening to the gas discharge flow path is provided in the other non-power-generation region in the predetermined direction than the power-generation region of the cell stack.

Description

Technical Field

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

[0002] In recent years, in order to enable more people to use cost-effective, reliable, sustainable, and advanced energy, technological development of fuel cells that contribute to improving energy efficiency has been underway. As a technology related to such fuel cells, there has been conventionally known a fuel cell system in which a stirrer for swirling a fuel gas is provided in a flow channel for supplying the fuel gas to a fuel cell stack to suppress the concentration of impurities such as water near the inlet of the fuel cell. Such a fuel cell stack is described in, for example, Patent Document 1.

[0003] However, as in the fuel cell system described in Patent Document 1, when a stirrer is provided in the flow channel for supplying the fuel gas to the fuel cell stack, the pressure loss in the flow channel increases, hindering the smooth flow of the fuel gas.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-145427 (JP2019-145427A). Summary of the Invention

[0007] A fuel cell stack according to one aspect of the present invention includes: a cell stack having a plurality of power generation cells stacked in a predetermined direction, a gas supply flow channel for supplying a reaction gas and a gas discharge flow channel for discharging the reaction gas respectively extending along the predetermined direction, and a gas flow channel connecting the gas supply flow channel and the gas discharge flow channel; a first end unit disposed on one side in the predetermined direction of the cell stack, having a supply port communicating with the gas supply flow channel and a discharge port communicating with the gas discharge flow channel; a second end unit disposed on the other side in the predetermined direction of the cell stack; and a tube body disposed in the gas supply flow channel, extending in the predetermined direction and having a first opening communicating with the upstream side and a second opening communicating with the downstream side of the gas supply flow channel at one end side in one direction and the other end side in the other direction of the predetermined direction, respectively. A drainage channel for guiding the liquid water flowing out from the second opening to the gas discharge flow channel is provided in a non-power generation area on the other side in the predetermined direction with respect to the power generation area of the cell stack having a plurality of power generation cells.

[0008] By adopting the present invention, smooth flow of the reaction gas can be ensured, and the liquid water can be discharged well without passing through the power generation cells. Brief Description of the Drawings

[0009] The objects, features, and advantages of the present invention will be further clarified by the following description of the embodiments in relation to the accompanying drawings.

[0010] Figure 1 is a perspective view schematically showing the overall structure of a fuel cell stack according to an embodiment of the present invention;

[0011] Figure 2 shows Figure 1 a perspective view schematically showing the structure of an integrated electrode assembly included in the fuel cell stack;

[0012] Figure 3 is a cross-sectional view showing the main part structure of the fuel cell stack cut along the fuel gas supply flow path;

[0013] Figure 4A is a Figure 3 main part enlarged view showing the structure of the front support portion;

[0014] Figure 4B is Figure 4A a view in the direction of IVB of

[0015] Figure 5A is a Figure 3 main part enlarged view showing the structure of the rear support portion of

[0016] Figure 5B is Figure 5A a view in the direction of VB of

[0017] Figure 6 constitutes Figure 2 a main part enlarged view of the frame of the integrated electrode assembly of

[0018] Figure 7 schematically shows Figure 3 the flow of fuel gas and liquid water in the fuel gas supply flow path of

[0019] Figure 8 shows Figure 7 a modified example of

[0020] Figure 9 is a cross-sectional view showing a modified example of the through hole of the gas supply flow path provided in the end unit. Detailed Embodiments

[0021] Hereinafter, embodiments of the present invention will be described with reference to Figures 1 - 9 A fuel cell stack according to an embodiment of the present invention is a main component of a fuel cell. The fuel cell is installed in a vehicle, for example, and can generate electric power for driving the vehicle. First, the overall structure of the fuel cell stack will be schematically described.

[0022] Figure 1FIG. 0 is a perspective view schematically showing the overall structure of the fuel cell stack 100 of the present embodiment. For convenience, hereinafter, three mutually orthogonal axial directions are defined as the front-rear direction, the left-right direction, and the up-down direction, and the structure of each part will be described according to this definition. The lower side in the up-down direction corresponds to the direction of gravity, for example. The front-rear direction corresponds to the stacking direction of the fuel cell stack 100. The front-rear direction and the left-right direction do not necessarily coincide with the front-rear direction and the left-right direction of the vehicle. For example Figure 1 the front-rear direction of Figure 1 can be the front-rear direction of the vehicle or the left-right direction.

[0023] As Figure 1 shown, the fuel cell stack 100 has a battery stack body 101 formed by stacking a plurality of power generation cells 1 in the front-rear direction, and end units 102 disposed at the front and rear ends of the battery stack body 101, and is generally rectangular parallelepiped in shape as a whole. Although not shown, the periphery of the battery stack body 101 is covered by a generally rectangular parallelepiped housing. The length of the battery stack body 101 in the left-right direction is longer than the length in the up-down direction. For convenience, Figure 1 a single power generation cell 1 is shown in Figure 1 .

[0024] The power generation cell 1 has: an integrated electrode assembly 2 (Unitized Electrode Assembly, hereinafter referred to as UEA), which has a joined body including an electrolyte membrane and an electrode (membrane electrode joined body); and separators 3, 3, which are disposed on both sides in the front-rear direction of the UEA 2 and sandwich the UEA 2. The UEA 2 and the separators 3 are alternately arranged in the front-rear direction.

[0025] The separator 3 has a pair of front and rear thin metal plates having a corrugated plate cross section (refer to Figure 3 ), and the outer peripheral edges of these thin plates are joined to each other to form an integral body. The separator 3 is made of a material with good corrosion resistance and conductivity, and for example, stainless steel, titanium, titanium alloy, etc. can be used. A cooling flow path for the cooling medium to flow is formed inside the separator 3 (between the pair of thin plates), and the power generation surface of the power generation cell 1 is cooled by the flow of the cooling medium. For example, water can be used as the cooling medium. The surfaces (front surface and rear surface) of the separator 3 facing the UEA 2 are formed into concave and convex shapes by stamping or the like, so that gas flow paths are formed between the separator 3 and the membrane electrode joined body of the UEA 2.

[0026] The separator 3 on the front side of the UEA 2 is, for example, an anode side separator (anode separator), and an anode flow path PAa for fuel gas (anode gas) to flow is formed between the anode separator 3 and the membrane electrode joined body of the UEA 2 (refer to Figure 3 ). The separator 3 on the rear side of the UEA 2 is, for example, a cathode side separator (cathode separator), and a cathode flow path PAc for oxidant gas (cathode gas) to flow is formed between the cathode separator 3 and the membrane electrode joined body of the UEA 2 (refer toFigure 3 )。The fuel gas is a gas containing hydrogen, such as hydrogen gas that can be used. The oxidant gas is a gas containing oxygen, such as air that can be used. Sometimes, the fuel gas and the oxidant gas are not distinguished and are referred to as reaction gases.

[0027] Figure 2 is a perspective view showing the schematic structure of the UEA2. As Figure 2 shown, the UEA2 has a membrane electrode assembly 20 (Membrane Electrode Assembly, hereinafter referred to as MEA) having a substantially rectangular shape and a frame 21 that supports the MEA 20. The MEA 20 has an electrolyte membrane, an anode electrode provided on the front surface of the electrolyte membrane, and a cathode electrode provided on the rear surface of the electrolyte membrane.

[0028] The electrolyte membrane is, for example, a solid polymer electrolyte membrane, and a thin film containing perfluorosulfonic acid with moisture can be used. Not limited to fluorine-based electrolyte membranes, hydrocarbon-based electrolyte membranes can also be used.

[0029] The anode electrode has an electrode catalyst layer formed on the front surface of the electrolyte membrane and serving as a reaction field for the electrode reaction, and a gas diffusion layer provided on the front surface of the electrode catalyst layer for diffusing and supplying the fuel gas. The cathode electrode has an electrode catalyst layer formed on the rear surface of the electrolyte membrane and serving as a reaction field for the electrode reaction, and a gas diffusion layer provided on the rear surface of the electrode catalyst layer for diffusing and supplying the oxidant gas. The electrode catalyst layer includes a catalyst metal that promotes the electrochemical reaction between the hydrogen contained in the fuel gas and the oxygen contained in the oxidant gas, an electrolyte having proton conductivity, and carbon particles having electron conductivity, etc. The gas diffusion layer is composed of a conductive member having air permeability, such as a carbon porous body.

[0030] In the anode electrode, the fuel gas (hydrogen) supplied via the anode flow channel is ionized by the action of the catalyst and moves to the cathode electrode side through the electrolyte membrane. The electrons generated at this time pass through the external circuit and are taken out as electric energy. In the cathode electrode, the oxidant gas (oxygen) supplied via the cathode flow channel reacts with the hydrogen ions introduced from the anode electrode and the electrons that have moved from the anode electrode to generate water. The generated water (referred to as generated water) gives appropriate humidity to the electrolyte membrane, and the remaining water is discharged to the outside of the UEA2 as the gas flows. The generated water on the cathode side also flows to the anode side through back-diffusion via the electrolyte membrane. Therefore, generated water exists in both the anode flow channel and the cathode flow channel.

[0031] The frame 21 is a thin plate in a substantially rectangular shape and is made of an insulating resin, rubber, or the like. A substantially rectangular opening 21a is provided in the central portion of the frame 21. The MEA 20 is provided so as to cover the entire opening 21a, and the peripheral portion of the MEA 20 is supported by the frame 21. On the left side of the opening 21a of the frame 21, three through-holes 211 to 213 penetrating the frame 21 in the front-rear direction are arranged along the vertical direction. On the right side of the opening 21a, three through-holes 214 to 216 penetrating the frame 21 in the front-rear direction are arranged along the vertical direction. For convenience, the through-holes 211 to 216 are all shown in a substantially rectangular shape, but the shapes and arrangements of the through-holes 211 to 216 are not limited thereto.

[0032] As Figure 1 shown, in the front and rear partition plates 3 of the UEA 2, through-holes 311 to 316 penetrating the partition plates 3 in the front-rear direction are respectively provided at positions corresponding to the through-holes 211 to 216 of the frame 21. The through-holes 311 to 316 are respectively communicated with the through-holes 211 to 216 of the frame 21. A set of these mutually communicated through-holes 211 to 216 and 311 to 316 forms flow channels PA1 to PA6 (shown by arrows for convenience) that penetrate the battery laminate 101 and extend in the front-rear direction. The flow channels PA1 to PA6 are sometimes also referred to as manifolds (internal manifolds). The flow channels PA1 to PA6 are connected to the manifolds outside the fuel cell stack 100.

[0033] The flow channel PA1 (solid arrow) extending forward via the through-holes 211 and 311 is a fuel gas supply flow channel. The flow channel PA6 (solid arrow) extending rearward via the through-holes 216 and 316 is a fuel gas discharge flow channel. The fuel gas supply flow channel PA1 and the fuel gas discharge flow channel PA6 are communicated with the anode flow channel, and the anode flow channel is provided facing the front surface of the MEA 20. As shown by the solid arrows, the fuel gas (anode gas) flows from the left side (upper left) to the right side (lower right) in the anode flow channel via the fuel gas supply flow channel PA1 and the fuel gas discharge flow channel PA6. The communication between the anode flow channel and the other flow channels PA2 to PA5 is cut off by a sealing portion (not shown). The fuel gas flowing in the fuel gas discharge flow channel PA6 is the fuel gas after a part of it has been used at the anode electrode and is sometimes referred to as fuel exhaust (anode exhaust gas).

[0034] The flow path PA4 (dashed arrow) extending forward through the through-holes 214 and 314 is the oxidant gas supply flow path. The flow path PA3 (dashed arrow) extending rearward through the through-holes 213 and 313 is the oxidant gas discharge flow path. The oxidant gas supply flow path PA4 and the oxidant gas discharge flow path PA3 communicate with the cathode flow path, and the cathode flow path is disposed facing the rear surface of the MEA 20. As shown by the dashed arrow, the oxidant gas (cathode gas) flows from the right side (upper right) to the left side (lower left) in the cathode flow path via the oxidant gas supply flow path PA4 and the oxidant gas discharge flow path PA3. The communication between the cathode flow path and the other flow paths PA1, PA2, PA5, and PA6 is cut off by a sealing portion (not shown). The oxidant gas flowing in the oxidant gas discharge flow path PA3 is the oxidant gas after a part of it has been used at the cathode electrode, and is sometimes referred to as oxidant exhaust gas (cathode exhaust gas). Sometimes, without distinguishing between fuel exhaust gas and oxidant exhaust gas, they are also referred to as reaction exhaust gas.

[0035] The flow path PA5 (one-dot chain line arrow) extending forward through the through-holes 215 and 315 is the cooling medium supply flow path. The flow path PA2 (one-dot chain line arrow) extending rearward through the through-holes 212 and 312 is the cooling medium discharge flow path. The cooling medium supply flow path PA5 and the cooling medium discharge flow path PA2 communicate with the cooling flow path inside the separator 3, and the cooling medium flows in the cooling flow path via the cooling medium supply flow path PA5 and the cooling medium discharge flow path PA2. The communication between the cooling flow path and the other flow paths PA1, PA3, PA4, and PA6 is cut off by a sealing portion (not shown).

[0036] The end units 102 disposed on both ends of the battery stack 101 in the front-rear direction respectively have terminal plates 4, insulating plates 5, and end plates 6. Sometimes, the front-side end unit 102 is also referred to as the dry-side end unit, and the rear-side end unit 102 is also referred to as the wet-side end unit. A pair of front and rear terminal plates 4, 4 are disposed on both sides of the battery stack 101 in the front-rear direction with the battery stack 101 interposed therebetween. A pair of front and rear insulating plates 5, 5 are disposed on both sides of the terminal plates 4, 4 in the front-rear direction with the terminal plates 4, 4 interposed therebetween. A pair of front and rear end plates 6, 6 are disposed on both sides of the insulating plates 5, 5 in the front-rear direction with the insulating plates 5, 5 interposed therebetween.

[0037] The terminal board 4 is a plate-shaped member made of metal and having a substantially rectangular shape, and has a terminal portion for taking out the electric power generated by the electrochemical reaction in the battery stack 101. The insulating board 5 is a plate-shaped member made of a non-conductive resin or rubber and having a substantially rectangular shape, and electrically insulates the terminal board 4 and the end board 6. The end board 6 is a plate-shaped member made of metal or a resin having high strength, and the front and rear end boards 6, 6 are fixed to the front end portion and the rear end portion of the housing including the battery stack 101 by bolts, for example, in a state where a predetermined compressive load is applied in the front-rear direction. The fuel cell stack 100 is held by the housing in a state of being pressed in the front-rear direction.

[0038] A plurality of through holes 102a to 102f penetrating the end unit 102 in the front-rear direction are formed in the rear end unit 102. The through holes 102a to 102f each include a through hole penetrating the terminal board 4, a through hole penetrating the insulating board 5, and a through hole penetrating the end board 6. For convenience, in Figure 1 this text, they are collectively referred to as through holes 102a to 102f. The through hole 102a is formed on the extension line of the fuel gas supply passage PA1 and communicates with the fuel gas supply passage PA1. The through hole 102b is formed on the extension line of the cooling medium discharge passage PA2 and communicates with the cooling medium discharge passage PA2. The through hole 102c is formed on the extension line of the oxidant gas discharge passage PA3 and communicates with the oxidant gas discharge passage PA3. The through hole 102d is formed on the extension line of the oxidant gas supply passage PA4 and communicates with the oxidant gas supply passage PA4. The through hole 102e is formed on the extension line of the cooling medium supply passage PA5 and communicates with the cooling medium supply passage PA5. The through hole 102f is formed on the extension line of the fuel gas discharge passage PA6 and communicates with the fuel gas discharge passage PA6.

[0039] More specifically, the through hole 102a is connected to a fuel gas tank storing high-pressure fuel gas via an ejector, a jet ejector, etc., and the fuel gas in the fuel gas tank is supplied to the fuel cell stack 100 via the through hole 102a. A gas-liquid separator is connected to the through hole 102f, and the fuel gas (fuel exhaust gas) discharged through the through hole 102f is separated into fuel gas and water by the gas-liquid separator. The separated fuel gas is sucked in via an ejector and supplied to the fuel cell stack 100 again via the through hole 102a. The separated water is discharged to the outside via a drainage passage.

[0040] A compressor for supplying oxidant gas is connected to the through-hole 102d, and the oxidant gas compressed by the compressor is supplied to the fuel cell stack 100 via the through-hole 102d. The oxidant gas (oxidant exhaust gas) flows out to the outside through the through-hole 102c. A pump for supplying a cooling medium is connected to the through-hole 102e, and the cooling medium is supplied to the fuel cell stack 100 via the through-hole 102e. The cooling medium is discharged from the through-hole 102b. The discharged cooling medium is cooled by heat exchange in a radiator and then supplied to the fuel cell stack 100 again via the through-hole 102e.

[0041] The above is the schematic structure of the fuel cell stack 100. The fuel cell stack 100 is housed in a substantially box-shaped housing and installed in a vehicle.

[0042] However, at the anode electrode, water is generated due to diffusion from the cathode electrode side through the electrolyte membrane. This generated water flows through the anode flow channel to the fuel gas discharge flow channel PA6 and is discharged together with the fuel exhaust gas. However, during fuel gas recirculation, it sometimes flows into the fuel gas supply flow channel PA1 together with the fuel gas. Condensate is generated inside the fuel cell stack 100 and in the pipes constituting the external manifold, and sometimes this condensate also flows into the fuel gas supply flow channel PA1 together with the fuel gas. Hereinafter, the generated water and the condensate are collectively referred to as liquid water. The liquid water not only flows into the fuel gas supply flow channel PA1 but also into the oxidant gas supply flow channel PA4.

[0043] In this way, when liquid water flows into the supply flow channels (gas supply flow channels) PA1 and PA4 of the reaction gas, the liquid water is guided to the power generation surface of the power generation cell 1, which may cause unstable power generation and a decrease in power generation performance. In order to avoid the inflow of such liquid water, when a stirrer or the like is arranged in the external manifold upstream of the gas supply flow channels PA1 and PA4, the pressure loss increases, and it is difficult to obtain the desired power generation performance. Therefore, the fuel cell stack 100 is configured as follows to suppress the decrease in power generation performance caused by the liquid water flowing in from the gas supply flow channels PA1 and PA4.

[0044] The structures of the fuel gas supply flow channel PA1 and the oxidant gas supply flow channel PA4 are substantially the same. Therefore, the structures of the gas supply flow channels PA1 and PA4 are described below with respect to the fuel gas supply flow channel PA1. Figure 3 It is a cross-sectional view showing the main part structure of the fuel cell stack 100 cut along the fuel gas supply flow channel PA1.

[0045] In Figure 3 order to distinguish the structures of the front and rear end units 102, the front end unit 102 is represented by the terminal plate 40, the insulating plate 50, and the end plate 60, and the rear end unit 102 is represented by the terminal plate 41, the insulating plate 51, and the end plate 61. As Figure 3As shown, the fuel gas supply flow path PA1 extends in the front-rear direction through the through hole 102a of the rear end unit 102, the through holes 211 and 311 of the battery stack 101, and the through hole 102a of the front end unit 102. Therefore, a flow path forming portion for forming the fuel gas supply flow path PA1 is provided in the end unit 102 and the battery stack 101.

[0046] The through hole 102a of the front end unit 102 includes the through hole 40a of the terminal plate 40 and the through hole 50a of the insulating plate 50. The front end of the fuel gas supply flow path PA1 is closed by the end plate 60. The through hole 102a of the rear end unit 102 includes the through hole 41a of the terminal plate 41, the through hole 51a of the insulating plate 51, and the through hole 61a of the end plate 61.

[0047] The battery stack 101 has a plurality of power generation cells 1 as power generation bodies and dummy cells 1d as non-power generation bodies. The dummy cells 1d are sandwiched between the last power generation cell 1 and the rear terminal plate 41, and between the foremost power generation cell 1 and the front terminal plate 40. More specifically, two sets of dummy cells 1d are respectively sandwiched between the power generation cell 1 and the terminal plates 40 and 41.

[0048] The dummy cell 1d has a pair of front and rear separators 3, 3 having the same structure as the power generation cell 1 and a dummy component 2d sandwiched between the separators 3, 3. The dummy component 2d has a frame 21 and a dummy bonding body 20d having the same structure as the power generation cell 1. That is, the dummy cell 1d is different from the power generation cell 1 in that it has a dummy bonding body 20d instead of the MEA20.

[0049] The dummy bonding body 20d is a conductive plate and electrode bonding body provided so as to cover the opening 21a ( Figure 2 ) of the frame 21. Therefore, the dummy cell 1d does not have an electrolyte membrane and does not generate electricity in the dummy cell 1d. Thus, by arranging the dummy cells 1d adjacent to the front and rear ends of the power generation cell 1 in the front-rear direction, the dummy cells 1d function as a heat insulating layer and can suppress the temperature drop of the power generation cell 1. Figure 3 In, two sets of dummy cells 1d are respectively arranged between the power generation cell 1 and the terminal plates 40 and 41, but one set or three or more sets of dummy cells 1d can also be arranged. It is also possible to omit the dummy cells 1d on one or both of the front side and the rear side.

[0050] A communication pipe 7 is provided along the flow path PA1 on the upper surface of the flow path of the fuel gas supply flow path PA1. Although detailed illustration is omitted, around the through hole 311 of the separator 3 constituting the flow path PA1, in the region from the lower surface to the right surface of the through hole 311 ( Figure 6In the region AR1), a communication flow path 3b that connects the flow path PA1 and the anode flow path PAa is provided. The communication pipe 7 is provided in a region (upper surface) of the inner wall surface of the flow path PA1 that is different from the region (from the lower surface to the right surface) where the communication flow path 3b is provided. The communication flow path 3b is constituted by, for example, a hole portion that horizontally penetrates a rib-shaped sealing portion (metal projection seal 3c) in the vertical direction.

[0051] The communication pipe 7 is an elongated pipe member having a substantially annular cross-section with openings (front end opening 71a, rear end opening 72a) provided at the front end portion 71 and the rear end portion 72, respectively, and extends linearly in the front-rear direction through the fuel cell stack 101. The front end opening 71a of the communication pipe 7 is located in the internal space SP1 of the through hole 102a of the front end unit 102 on the front side, and more specifically, inside the through hole 50a of the insulating plate 50. The rear end opening 72a of the communication pipe 7 is located in the internal space SP2 of the through hole 102a of the rear end unit 102 on the rear side, and more specifically, inside the through hole 51a of the insulating plate 51. Therefore, the internal space SP1 of the front end unit 102 on the front side and the internal space SP2 of the rear end unit 102 on the rear side are connected via the communication pipe 7.

[0052] The communication pipe 7 is formed of a constituent material such as resin, rubber, or glass. However, when considering vibrations and temperature changes in the fuel cell stack 100, the communication pipe 7 is preferably formed of a flexible resin or rubber. The pressure on the upstream side of the fuel gas supply flow path PA1, that is, the internal space SP2, is higher than the pressure on the downstream side, that is, the internal space SP1. In the communication pipe 7, water flows from the rear end opening 72a to the front end opening 71a according to the pressure difference between the internal spaces SP1 and SP2. Therefore, the cross-sectional area of the communication pipe 7 is set to be sufficiently smaller than the cross-sectional area of the fuel gas supply flow path PA1, but capable of flowing a specified amount or more of water. In other words, the communication pipe 7 forms a narrow region in the flow path PA1 with a cross-sectional area significantly smaller than that of the flow path PA1.

[0053] The front end portion of the communication pipe 7 is supported by a front support portion 201 provided in the front end unit 102 on the front side. The rear end portion of the communication pipe 7 is supported by a rear support portion 202 provided in the rear end unit 102 on the rear side.

[0054] Figure 4A is a main part enlarged view showing the structure of the front support portion 201, Figure 3 and Figure 4B is Figure 4A a view in the IVB direction (viewed from the front). As Figure 4A 、 Figure 4B shown, on the upper surface of the through hole 50a of the insulating plate 50, a bulging portion 52 that bulges downward is provided at the middle portion in the front-rear direction starting from its rear end portion. In Figure 4AIn [the figure], the bulging portion 52 has a protruding portion 52a that protrudes rearward, and the protruding portion 52a is located inside the through hole 40a of the terminal plate 40. Therefore, a part of the insulating plate 50 is configured to be long in the front-rear direction, and the front end portion of the communication pipe 7 is supported by this length portion.

[0055] In the bulging portion 52, a through hole 520 having a circular cross-section is formed centered on an axis CL0 extending in the front-rear direction from its front end face 525 to the rear end face 526. The through hole 520 is bounded by a boundary surface 527 extending in the up-down direction perpendicular to the axis CL0, and includes a wedge-shaped portion 521 behind the boundary surface 527 and a straight portion 522 in front of the boundary surface 527. The wedge-shaped portion 521 is formed in a tapered shape such that the cross-sectional area gradually decreases from the rear end face 526 of the bulging portion 52 to the boundary surface 527. That is, it is formed to have a frustum-shaped space inside. The straight portion 522 is formed in a straight line shape such that the cross-sectional area remains constant or substantially constant from the front end face 525 of the bulging portion 52 to the boundary surface 527. The cross-sectional area of the straight portion 522 is smaller than the cross-sectional area at the front end of the wedge-shaped portion 521. The angle between the wedge-shaped portion 521 and the axis CL0 is about several degrees (for example, 2 to 3° or 4 to 5°), and the length of the wedge-shaped portion 521 in the front-rear direction is longer than the length of the straight portion 522 in the front-rear direction.

[0056] The diameter of the outer peripheral surface of the communication pipe 7 is larger than the diameter of the front end face (boundary surface 527) of the wedge-shaped portion 521 and smaller than the diameter of the rear end face 526 of the wedge-shaped portion 521. The diameter of the inner peripheral surface of the communication pipe 7 is the same as or smaller than the diameter of the straight portion 522. Thus, when the communication pipe 7 is inserted into the through hole 520 from the rear of the bulging portion 52, the outer peripheral corner portion at the front end of the communication pipe 7 abuts against the peripheral surface of the wedge-shaped portion 521, and the center line CL1 of the communication pipe 7 coincides with the axis CL0. As a result, the front end portion of the communication pipe 7 can be supported by the insulating plate 50 in a state where the front end portion of the communication pipe 7 is positioned by the wedge-shaped portion 521. The movement of the communication pipe 7 is restricted by the wedge-shaped portion 521, so that the position shift of the communication pipe 7 can also be prevented. In a state where the communication pipe 7 is supported by the front support portion 201, the front end opening 71a of the communication pipe 7 communicates with the internal space SP1 of the end unit 102, and more specifically, with the internal space SP1 in front of the bulging portion 52 via the through hole 520.

[0057] Figure 5A It is a main part enlarged view showing the structure of the rear support portion 202, Figure 3 and Figure 5B is Figure 5A a view in the VB direction (a view observed from the rear) of Figure 5A . As Figure 5B shown, on the upper surface of the through hole 51a of the insulating plate 51, a bulging portion 53 that bulges downward is provided at the intermediate portion in the front-rear direction from its front end portion. In Figure 5AIn this case, the bulged portion 53 has a protruding portion 53a that protrudes forward, and the protruding portion 53a is located inside the through hole 41a of the terminal plate 41. Therefore, a part of the insulating plate 51 is configured to be longer in the front-rear direction, and the rear end portion of the communication pipe 7 is supported by this length portion.

[0058] In the bulged portion 53, a through hole 530 having a circular cross-section is formed from its rear end face 535 to its front end face 536 with the axis CL0 extending in the front-rear direction as the center. The through hole 530 is bounded by a boundary surface 537 that extends in the up-down direction perpendicular to the axis CL0, and includes a wedge-shaped portion 531 in front of the boundary surface 537 and a straight portion 532 behind the boundary surface 537. The wedge-shaped portion 531 is formed in a tapered shape such that the cross-sectional area gradually decreases from the front end face 536 of the bulged portion 53 to the boundary surface 537. That is, it is formed to have a frustum-shaped space inside. The straight portion 532 is formed in a straight shape such that the cross-sectional area remains constant or substantially constant from the rear end face 535 of the bulged portion 53 to the boundary surface 537. The cross-sectional area of the straight portion 532 is smaller than the cross-sectional area of the rear end of the wedge-shaped portion 531. The angle between the wedge-shaped portion 531 and the axis CL0 is about several degrees (for example, 2 to 3° or 4 to 5°), and the length of the wedge-shaped portion 531 in the front-rear direction is longer than the length of the straight portion 532 in the front-rear direction.

[0059] The diameter of the outer peripheral surface of the communication pipe 7 is larger than the diameter of the rear end face (boundary surface 537) of the wedge-shaped portion 531 and smaller than the diameter of the front end face 536 of the wedge-shaped portion 531. The diameter of the inner peripheral surface of the communication pipe 7 is the same as or smaller than the diameter of the straight portion 532. Thus, when the communication pipe 7 is inserted into the through hole 530 from the front of the bulged portion 53, the outer peripheral corner portion of the rear end of the communication pipe 7 abuts against the peripheral surface of the wedge-shaped portion 531, and the center line CL1 of the communication pipe 7 coincides with the axis CL0. As a result, the rear end portion of the communication pipe 7 can be supported by the insulating plate 51 in a state where the rear end portion of the communication pipe 7 is positioned by the wedge-shaped portion 531. The movement of the communication pipe 7 is restricted by the wedge-shaped portion 531, so that the position deviation of the communication pipe 7 can also be prevented. In a state where the communication pipe 7 is supported by the rear support portion 202, the rear end opening 72a of the communication pipe 7 communicates with the internal space SP2 of the end unit 102, and more specifically, with the internal space SP2 behind the bulged portion 53 via the through hole 530.

[0060] In addition to supporting the communication pipe 7 by the support portions 201 and 202 of the front and rear end units 102, the communication pipe 7 can also be supported by the frame 21 of the UEA2 included in the battery laminate 101. That is, an intermediate support portion for supporting the intermediate portion of the communication pipe 7 in the front-rear direction can also be provided. Figure 6 is a front view (a view observed from the rear) showing the structure of the through hole 211 ( Figure 2 ) of the fuel gas supply frame 21 provided with the intermediate support portion 203. AsFigure 6 As shown, a pair of left and right protrusions 217 and 218 protruding downward are provided on the upper surface of the through-hole 211 of the frame 21. The protrusions 217 and 218 are formed in a substantially arc shape so as to form a substantially cylindrical space SP3 along the upper surface of the through-hole 211.

[0061] The communication pipe 7 is inserted into the space SP3 from the front or rear of the battery stack 101. The diameter of the space SP3 is slightly larger than the outer diameter of the communication pipe 7 so that the communication pipe 7 can be easily inserted. Thus, the middle portion in the front-rear direction of the communication pipe 7 is positioned by the protrusions 217 and 218, and the communication pipe 7 can be stably supported. However, since the front and rear ends of the communication pipe 7 are positioned by the wedge portions 521 and 531, the protrusions 217 and 218 are provided for loose positioning to the extent that the positioning of the wedge portions 521 and 531 is not damaged. Therefore, it is not necessary to improve the accuracy of the protrusions 217 and 218 so much.

[0062] The protrusions 217 and 218 constitute an intermediate support portion 203 that supports the middle portion of the communication pipe 7. The intermediate support portion 203 can be provided in all the frames 21 included in the battery stack 101, or can be provided in a part of the frames 21. The top ends of the protrusions 217 and 218 can also be connected to each other to provide a single protrusion, and an opening that is substantially circular in the front view can be provided in the protrusion to form the intermediate support portion 203. Although it depends on the material of the communication pipe 7, when the communication pipe 7 has high rigidity and can be firmly supported by the front support portion 201 and the rear support portion 202, the intermediate support portion 203 can be omitted. The front support portion 201 and the rear support portion 202 can also be configured to only limit the position of the communication pipe 7 in the front-rear direction, and the intermediate support portion 203 limits the position of the communication pipe 7 in the up-down direction and the left-right direction.

[0063] As Figure 3 , Figure 5A shown, the peripheral surface of the through-hole 51a of the insulating plate 51, especially the inner peripheral surface of the uppermost part, is configured as a flat surface 51b that is flat in the front-rear direction. The inner peripheral surface of the uppermost part of the straight portion 532 is located on an extended surface obtained by extending the flat surface 51b forward, and the peripheral surface of the through-hole 51a is connected to the inner peripheral surface of the straight portion 532 without a height difference.

[0064] As Figure 3As shown, on the rear end plate 61, the upper end 81 of a substantially L-shaped pipe 8 is installed in communication with the through-hole 61a. The pipe 8 extends downward by means of a bent portion 8a, and the lower end 82 of the pipe 8 opens downward. For example, an ejector is connected to the lower end 82 of the pipe 8. The pipe 8 forms an external flow path PA15 having an opening surface 82a at the lower end. As indicated by the arrow, fuel gas is supplied to the inside of the pipe 8 from below. After the supplied fuel gas flows upward and collides with the inner peripheral surface of the upper end (bent portion 8a) of the pipe 8, the flow direction changes to the front, and the fuel gas flowing into the fuel gas supply flow path PA1 inside the battery laminate 101.

[0065] On the front insulating plate 50, a communication hole 55 is provided to connect the fuel gas supply flow path PA1 and the fuel gas discharge flow path PA6 ( Figure 1 ). The opening 55a of the communication hole 55 on the fuel gas supply flow path PA1 side is located on the bottom surface of the through-hole 50a. The opening 55a is provided at the same position or substantially the same position as the front end surface 525 of the bulging portion 52 ( Figure 4A ) in the front-rear direction, or is provided in front of the front end surface 525. The communication hole 55 forms a drainage channel PA10 for guiding the liquid water to the fuel gas discharge flow path PA6.

[0066] The main operation of the fuel cell stack 100 configured as described above will be described. Figure 7 It is a diagram schematically showing the flow of fuel gas and liquid water in the fuel gas supply flow path PA1. Although not shown, the fuel gas supply flow path PA1 and the oxidant gas supply flow path PA4 have substantially the same structure, so the flow of oxidant gas and liquid water in the oxidant gas supply flow path PA4 is also the same as Figure 7 the same. As shown by the arrow A1 in Figure 7 , the fuel gas flowing upward from below in the external flow path PA15 inside the pipe 8 after flowing in through the opening surface 82a changes its flow direction to the right and flows into the fuel gas supply flow path PA1.

[0067] In the fuel gas supply flow path PA1, the fuel gas disperses while flowing forward as shown by the arrow A2, and flows into the anode flow path PAa ( Figure 3 ) facing the power generation surface of the power generation cell 1 through the communication flow path 3b as shown by the arrow A3. Thus, power generation is performed in the power generation cell 1. Due to the flow of the fuel gas in this way, the pressure in the flow path PA1 gradually decreases toward the front. Therefore, in the fuel gas supply flow path PA1, the pressure P2 in the internal space SP2 near the rear end opening 72a of the communication pipe 7 is the largest, the pressure P1 in the internal space SP1 near the front end opening 71a of the communication pipe 7 is the smallest, and the pressure difference (P2 - P1) between the internal spaces SP1 and SP2 is relatively large.

[0068] The pipe 8 has a bent portion 8a near the installation portion of the end unit 102. Therefore, the fuel gas containing liquid water (mainly generated water) collides with the inner peripheral surface of the pipe 8 near the bent portion 8a, and the liquid water is likely to adhere to the inner peripheral surface (upper surface) near the bent portion 8a. The outer surface of the bent portion 8a faces the atmosphere, and the temperature is likely to decrease. Therefore, in this regard, the liquid water is also likely to adhere (condensed water in this case). The liquid water w adhering to the inner peripheral surface of the bent portion 8a moves forward as shown by the arrow B1 along with the flow of the fuel gas, and then, as shown by the arrow B2, moves forward in the communication pipe 7 due to the pressure difference between the internal spaces SP1 and SP2. At this time, the liquid water w flows into the communication pipe 7 along the flat surface 51b on the upper surface of the through hole 51a. Therefore, the liquid water w can be easily guided into the interior of the communication pipe 7.

[0069] After the liquid water w that has flowed through the communication pipe 7 flows out from the front end opening 71a of the communication pipe 7, as shown by the arrow B3, it flows into the drainage passage PA10 through the opening 55a below the front end opening 71a. Further, the liquid water w flows into the fuel gas discharge passage PA6 through the drainage passage PA10 and is discharged from the fuel cell stack 100 along with the flow of the fuel exhaust gas. Thereby, it is possible to suppress the liquid water w in the gas supply passages PA1 and PA4 from being introduced into the power generation surface, and stable power generation performance can be obtained.

[0070] As described above, the drainage passage PA10 is provided in the front end unit 102. However, as long as it is a region different from the power generation region where the power generation cell 1 is provided (non-power generation region), the drainage passage can also be provided outside the end unit 102. For example, a drainage passage can also be provided in the front dummy cell 1d. Figure 8 This is a diagram schematically showing the flow of the fuel gas and the liquid water in the fuel gas supply passage PA1 in this case, and is a diagram showing Figure 7 a modified example of. Although not shown, the oxidant gas supply passage PA4 is also configured in the same manner as the fuel gas supply passage PA1.

[0071] As Figure 8 shown, a drainage passage PA11 that connects the fuel gas supply passage PA1 and the fuel gas discharge passage PA6 is provided in the front dummy cell 1d. The drainage passage PA11 is constituted by a gas passage (corresponding to the anode passage of the power generation cell 1) provided between the dummy component 2d and the partition plate 3 in the dummy cell 1d. Therefore, the drainage passage PA11 can be formed without applying new processing to the dummy cell 1d.

[0072] On the bottom surface of the communication pipe 7, an opening 71b is provided at the same position in the front-rear direction as the virtual battery 1d on the front side. At this time, the front end opening 71a of the communication pipe 7 is closed. Thus, according to the pressure difference between the internal space SP1 and the space in the flow path PA1 near the opening 71b (the space near the internal space SP1), the liquid water w flows inside the communication pipe 7, and the liquid water w flows out from the opening 71b. This liquid water w then flows through the drainage channel PA11 as shown by the arrow B4 and is guided to the fuel gas discharge channel PA6 and discharged from the fuel cell stack 100. The opening 71b of the communication pipe 7 may also be provided in front of the virtual battery 1d. It is also possible not to provide the opening 71b on the bottom surface of the communication pipe 7, open the front end opening 71a, allow the liquid water w to flow out from the front end opening 71a, and guide the flowing-out liquid water w to the drainage channel PA11 of the virtual battery 1d.

[0073] The following effects can be achieved by adopting this embodiment.

[0074] (1) The fuel cell stack 100 includes: a battery laminate 101 having a plurality of power generation cells 1 laminated in the front-rear direction, gas supply channels PA1, PA4 for supplying reaction gases and gas discharge channels PA3, PA6 for discharging reaction gases are respectively provided and extend along the front-rear direction, and gas channels (anode channels, cathode channels) connecting the gas supply channels PA1, PA4 and the gas discharge channels PA3, PA6 are provided; a rear end unit 102 disposed on the rear end side of the battery laminate 101, having through holes 102a, 102d (supply ports) communicating with the gas supply channels PA1, PA4 and through holes 102c, 102f (discharge ports) communicating with the gas discharge channels PA3, PA6; a front end unit 102 disposed on the front end side of the battery laminate 101; and a communication pipe 7 disposed in the gas supply channels PA1, PA4, extending in the front-rear direction and having a rear end opening 72a and a front end opening 71a ([ Figures 1 - 3 ) that communicate with the upstream internal space SP2 and the downstream internal space SP1 of the gas supply channels PA1, PA4, respectively. Drainage channels PA10, PA11 for guiding the liquid water flowing out from the front end opening 71a to the gas discharge channels PA3, PA6 are provided in the non-power generation area in front of the power generation area of the battery laminate 101 where a plurality of power generation cells 1 are arranged ([ Figure 3 , Figure 8 ).

[0075] With this structure, the liquid water flowing into the gas supply channels PA1 and PA4 is guided to the downstream side of the channels PA1 and PA4 via the communication pipe 7 over the power generation cell 1, so that the liquid water can be prevented from flowing from the channels PA1 and PA4 to the power generation surface. That is to say, the liquid water flowing into the gas supply channels PA1 and PA4 flows to the gas discharge channels PA3 and PA6 without passing through the anode channel and the cathode channel. As a result, stable power generation performance can be obtained and the reduction of power generation performance can be suppressed. In addition, there is no need to arrange a stirrer or the like on the upstream side of the channels PA1 and PA4, so that the increase in cost is suppressed and the pressure loss of the channels is suppressed, and the smooth flow of the reaction gas can be realized. That is, while ensuring the smooth flow of the reaction gas, the liquid water can be discharged well without passing through the power generation cell 1.

[0076] (2) The drainage channel PA10 is provided at the front end unit 102 ( Figure 3 . Figure 7 ). Thereby, the distance in the front-rear direction from the power generation cell 1 to the drainage channel PA10 can be extended, and the liquid water can be well prevented from mixing into the power generation cell 1. In addition, the pressure difference before and after the communication pipe 7 becomes larger, and the liquid water easily flows inside the communication pipe 7.

[0077] (3) The cell stack 101 has a dummy cell 1d ( Figure 3 ) as a non-power generation body between the plurality of power generation cells 1 and the front end unit 102. The drainage channel PA11 is provided in the dummy cell 1d ( Figure 8 ). Thereby, there is no need to form the drainage channel PA10 in the end unit 102, so that the fuel cell stack 100 can be constructed at a low cost.

[0078] (4) The communication pipe 7 is provided in such a way as to form a narrow region in a part of the gas supply channels PA1 and PA4 ( Figure 3 . Figure 6 ). Thereby, a part of the gas supply channels PA1 and PA4 is used as a flow channel for liquid water. Therefore, compared with the case where the flow channel for liquid water is provided in a space different from the gas supply channels PA1 and PA4, the fuel cell stack 100 is easily constructed.

[0079] (5) In a specified circumferential region AR1 (first region) of the inner wall surface of the channel in the front-rear direction of the cell stack 101 forming the gas supply channels PA1 and PA4, that is, the region from the right surface to the lower surface in the fuel gas supply channel PA1 and the region from the left surface to the lower surface in the oxidant gas supply channel PA4, communication channels 3b respectively communicating with the anode channel PAa and the cathode channel PAc are provided ( Figure 3)。The communication pipe 7 is provided in a region AR2 (second region) different from the region AR1 where the communication flow path 3b is provided, that is, on the upper surface of the inner wall surface of the flow path ( Figure 6 ). Thereby, it is possible to prevent the gas flow through the communication flow path 3b from being obstructed due to the provision of the communication pipe 7.

[0080] (6) A pipe 8 is further provided, which forms an external flow path PA15 communicating with the gas supply flow paths PA1 and PA4 from the lower end portion 82 to the upper end portion 81, and is connected to the end unit 102 in such a manner that the upper end portion 81 communicates with the through holes 102a and 102d of the rear end unit 102 ( Figure 3 ). The pipe 8 is configured such that an opening surface 82a is provided facing downward at the lower end portion 82 ( Figure 3 ). When the reaction gas is supplied through such a pipe 8, the reaction gas collides with the inner peripheral surface of the bent portion 8a of the pipe 8, and liquid water is likely to adhere to the vicinity of the bent portion 8a. In the present embodiment, the communication pipe 7 is arranged in a manner connected to the bent portion 8a, so that the liquid water can be easily guided to the communication pipe 7, and the drainage performance of discharging the liquid water from the flow paths PA1 and PA4 is improved.

[0081] (7) The peripheral surfaces of the through holes 102a and 102d of the rear end unit 102 have flat surfaces 51b, and the flat surfaces 51b extend flatly in the front-rear direction to the rear end opening 72a of the communication pipe 7 ( Figure 3 ). Thereby, the liquid water is smoothly guided to the communication pipe 7 along the flat surface 51b, and the drainage performance is improved.

[0082] (8) The rear end unit 102 has a rear support portion 202 that supports the rear end portion 72 of the communication pipe 7, and the front end unit 102 has a front support portion 201 that supports the front end portion 71 of the communication pipe 7 ( Figure 3 ). Thereby, the positions of both ends of the communication pipe 7 in the front-rear direction can be restricted, and thus the communication pipe 7 can be supported well.

[0083] The above-described embodiment can be deformed in various ways. Several modification examples will be described below. In the above-described embodiment, the communication pipe as a pipe body is arranged on the upper surface of the gas supply flow paths PA1 and PA4, but it can also be arranged other than the upper surface. For example, it can also be arranged on the lower surface (bottom surface) of the gas supply flow paths PA1 and PA4, or can be arranged on the right surface or the left surface. Figure 9 As an example, a diagram schematically showing an example provided on the bottom surface. In Figure 9In addition, the peripheral surfaces of through holes 102a and 102d of the end unit 102 communicating with the gas supply flow paths PA1 and PA4 have inclined surfaces 102g that slope downward and forward. Thus, the liquid water w near the through holes 102a and 102d can flow along the inclined surfaces 102g and easily flow into the interior of the communication pipe 7 through the rear end opening 72a of the communication pipe 7. As a result, the flow of the liquid water w through the communication pipe 7 can be promoted.

[0084] In the above-described embodiment, drainage channels PA10 and PA11 are provided in the front end unit 102 or the front dummy battery 1d, but as long as they are provided in a non-power generation area on the downstream side of the power generation area of the battery laminate in which a plurality of power generation batteries are arranged, the configuration of the drainage channels can be any manner. When the drainage channels are provided other than in the dummy battery 1d, the dummy battery 1d can also be omitted. In the above-described embodiment, a plurality of power generation batteries 1 are stacked in the front-rear direction (the specified direction), the end unit 102 (the first end unit) is arranged behind the power generation battery 1 on one side of the specified direction, and the end unit 102 (the second end unit) is arranged in front of the power generation battery 1 on the other side of the specified direction, but the stacking direction can also be a direction other than the front-rear direction. In this case, the stacking direction is preferably a substantially horizontal direction.

[0085] In the above-described embodiment, the communication pipe 7 as a pipe body is arranged along the upper surfaces (the second region) of the gas supply flow paths PA1 and PA4, but as long as it is a region different from the circumferential region (the first region) of the communication flow path 3b where the gas supply flow paths PA1 and PA4 are provided, the communication pipe 7 can be arranged in other regions. In the above-described embodiment, the rear end opening 72a as the first opening on the upstream side of the gas supply flow paths PA1 and PA4 and the front end opening 71a as the second opening on the downstream side are provided in the communication pipe 7, but the first opening and the second opening can also be provided at positions other than the rear end and the front end of the communication pipe. In the above-described embodiment, the front and rear ends of the communication pipe 7 are supported by the rear support portion 202 as the first support portion and the front support portion 201 as the second support portion, but the configuration of the first support portion and the second support portion is not limited to the above.

[0086] In the above-described embodiment, the gas supply flow paths PA1 and PA4 are configured to have a constant opening area in the front-rear direction, but the opening area can also vary in the front-rear direction. For example, the opening areas of the gas supply flow paths PA1 and PA4 can also be configured to obtain a Venturi effect. Thereby, the difference between the pressure P1 in the internal space SP1 facing the front end opening 71a of the communication pipe 7 and the pressure P2 in the internal space SP2 facing the rear end opening 72a can be increased, and the flow of the liquid water inside the communication pipe 7 can be promoted.

[0087] One or more of the above-described embodiments and modifications can be arbitrarily combined, and the modifications can also be combined with each other.

[0088] By adopting the present invention, while ensuring the smooth flow of the reaction gas, the liquid water can be discharged well without passing through the power generation battery.

[0089] The present invention has been described above in conjunction with the preferred embodiments, but those skilled in the art should understand that various modifications and changes can be made without departing from the scope of disclosure of the claims.

Claims

1. A fuel cell stack, characterized in that, Comprising: A battery laminate (101) having a plurality of power generation cells (1) laminated in a specified direction, with a gas supply flow path (PA1, PA4) for supplying reaction gas and a gas discharge flow path (PA3, PA6) for discharging reaction gas respectively extending along the specified direction, and a gas flow path (PAa, PAc) connecting the gas supply flow path (PA1, PA4) and the gas discharge flow path (PA3, PA6) is provided; A first end unit (102) disposed on one side of the battery laminate (101) in the specified direction, having a supply port (102a, 102d) communicating with the gas supply flow path (PA1, PA4) and a discharge port (102c, 102f) communicating with the gas discharge flow path (PA3, PA6); A second end unit (102) disposed on the other side of the battery laminate (101) in the specified direction; and A pipe body (7) disposed in the gas supply flow path (PA1, PA4), extending in the specified direction and having a first opening (72a) communicating with the upstream side and a second opening (71a) communicating with the downstream side of the gas supply flow path (PA1, PA4) respectively at one end side in one direction of the specified direction and the other end side in the other direction of the specified direction, A drainage channel (PA10, PA11) for guiding the liquid water flowing out from the second opening (71a) to the gas discharge flow path (PA3, PA6) is provided in a non-power generation area on the other side of the specified direction with respect to the power generation area of the battery laminate (101) where the plurality of power generation cells (1) are disposed.

2. The fuel cell stack according to claim 1, wherein The drainage channel (PA10) is provided in the second end unit (102).

3. The fuel cell stack according to claim 1, wherein The battery laminate (101) has a dummy cell (1d) as a non-power generation body between the plurality of power generation cells (1) and the second end unit (102), The drainage channel (PA11) is provided in the dummy cell (1d).

4. The fuel cell stack according to any one of claims 1 to 3, wherein The pipe body (7) is provided to form a narrow area in a part of the gas supply flow path (PA1, PA4).

5. The fuel cell stack according to any one of claims 1 to 3, wherein A communication channel (3b) communicating with the gas flow path (PAa, PAc) is provided in a first circumferential area (AR1) of the inner wall surface of the flow path forming the gas supply flow path (PA1, PA4), The pipe body (7) is disposed in a second circumferential area (AR2) of the inner wall surface of the flow path different from the first area (AR1).

6. The fuel cell stack according to any one of claims 1 to 3, characterized in that, Further comprising: A pipe (8) forms an external flow path (PA15) that communicates with the gas supply flow paths (PA1, PA4) from one end to the other end, and is connected to the first end unit (102) in such a way that the other end communicates with the supply ports (102a, 102d) of the first end unit (102). The pipe (8) is configured such that an opening surface (82a) is provided at one end facing a direction orthogonal to the specified direction.

7. The fuel cell stack according to any one of claims 1 to 3, characterized in that The peripheral surface of the supply ports (102a, 102d) has a flat surface (51d), and the flat surface (51d) extends flatly in the specified direction to the first opening (72a) of the pipe body (7).

8. The fuel cell stack according to any one of claims 1 to 3, characterized in that The first end unit (102) has a first support portion (202) that supports one end of the pipe body (7) in the specified direction. The second end unit (102) has a second support portion (201) that supports the other end of the pipe body (7) in the specified direction.

9. The fuel cell stack according to claim 8, characterized in that Each of the plurality of power generation cells (1) has an integrated electrode assembly (2) and a pair of separators (3, 3). The integrated electrode assembly (2) has a membrane electrode assembly (20) including an electrolyte membrane and an electrode, and a frame (21) that supports the membrane electrode assembly (20). The pair of separators (3, 3) are disposed on both sides of the integrated electrode assembly (2) in the specified direction. The gas supply flow paths (PA1, PA4) are formed by through holes (211, 214) provided in the frame (21) and through holes (311, 314) provided in the pair of separators (3, 3). The frame (21) has a third support portion (203) that supports the middle portion of the pipe body (7) in the specified direction around the through holes (211, 214) provided in the frame (21).

10. The fuel cell stack according to claim 8, characterized in that The first support portion (202) has a bulging portion (52) that bulges downward from the upper edge portion of the supply ports (102a, 102d) of the first end unit (102), and one end of the pipe body (7) passes through a through hole (520) provided in the bulging portion (52) and penetrating the bulging portion (52) in the specified direction to be supported.

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