Fuel cell stack

Abstract

A fuel cell stack is provided with: a cell stack (101) having a dummy cell (10) disposed adjacent to an end power generation cell (1a) positioned at one end of a plurality of power generation cells (1), a gas supply flow path (PA1, PA4) and a gas discharge flow path (PA3, PA6), and a gas discharge flow path (PA5, PA6) disposed adjacent to the dummy cell (10) and disposed adjacent to the end power generation cell (1a); and an end unit (102) provided with gas supply ports (102a, 102d) communicating with the gas supply flow paths (PA1, PA4) and gas discharge ports (102c, 102f) communicating with the gas discharge flow paths (PA3, PA6). A first communication hole (211) that constitutes a gas supply flow path is provided in the end power generation battery, and a second communication hole (211a) that constitutes a gas supply flow path is provided in the dummy battery. The first communication hole and the second communication hole are provided such that an extended surface, which extends in a predetermined direction from an opening surface of the second communication hole toward the first communication hole, does not coincide with an opening surface of the first communication hole.

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, a fuel cell stack in which a dummy cell is disposed on the dry side of the fuel cell stack and liquid water contained in the fuel gas supplied through the fuel gas supply passage is separated from the fuel gas on the downstream side of the dummy cell has been conventionally known. Such a fuel cell stack is described in, for example, Patent Document 1.

[0003] However, in the fuel cell stack described in Patent Document 1, the liquid water contained in the fuel gas is separated by the fuel gas supply passage before reaching the dummy cell on the dry side and flows toward the power generation cell, and the power generation performance may be unstable.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022-165808 (JP2022-165808A). 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 as power generation bodies stacked in a predetermined direction and a dummy cell as a non-power generation body disposed adjacent to an end power generation cell located at one end in the predetermined direction among the plurality of power generation cells, a gas supply flow path for supplying a reaction gas and a gas discharge flow path for discharging the reaction gas are respectively provided to extend along the predetermined direction, and a gas flow path for communicating the gas supply flow path and the gas discharge flow path is provided; and an end unit disposed adjacent to the dummy cell and provided with a gas supply port communicating with the gas supply flow path and a gas discharge port communicating with the gas discharge flow path. A first communication hole constituting the gas supply flow path is formed in the end power generation cell, and a second communication hole constituting the gas supply flow path is formed in the dummy cell. The first communication hole and the second communication hole are arranged such that the opening surface of the second communication hole faces the extension surface of the first communication hole extended in the predetermined direction and the opening surface of the first communication hole are not the same. Brief Description of the Drawings

[0008] The object, features, and advantages of the present invention will be further clarified by the following description of embodiments related to the drawings.

[0009] Figure 1 is a perspective view schematically showing the overall structure of a fuel cell stack according to an embodiment of the present invention;

[0010] Figure 2 is a cross-sectional view taken along line II-II of Figure 1 ;

[0011] Figure 3 is a perspective view schematically showing the schematic structure of the integrated electrode assembly included in the fuel cell stack of Figure 1 ;

[0012] Figure 4 is Figure 1 the rear view of the separator of

[0013] Figure 5 is a cross-sectional view taken along line V-V of Figure 1 ;

[0014] Figure 6A is a cross-sectional view taken along line A-A of Figure 4 ;

[0015] Figure 6B is a cross-sectional view taken along line B-B of Figure 4 ;

[0016] Figure 7A is a cross-sectional view schematically showing the structure of the first liquid water inflow suppression part provided in the fuel cell stack according to an embodiment of the present invention;

[0017] Figure 7B is Figure 7A the view in the direction of VIIB of

[0018] Figure 8 is a cross-sectional view schematically showing the structure of the second liquid water inflow suppression part provided in the fuel cell stack according to an embodiment of the present invention;

[0019] Figure 9A is a cross-sectional view schematically showing the structure of the third liquid water inflow suppression part provided in the fuel cell stack according to an embodiment of the present invention;

[0020] Figure 9B is Figure 9A the view in the direction of IXB of

[0021] Figure 10 is a cross-sectional view showing a modification example of the through hole of the gas supply flow path provided in the end unit. Detailed Embodiments

[0022] Hereinafter, embodiments of the present invention will be described with reference to Figures 1 to 10 . The 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.

[0023] Figure 1 FIG. 1 is a perspective view schematically showing the overall structure of the fuel cell stack 100 according to 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

[0024] As Figure 1 shown in FIG. 2, the fuel cell stack 100 has a cell stack 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 cell stack 101, and is generally rectangular parallelepiped in shape as a whole. Although not shown, the periphery of the cell stack 101 is covered by a generally rectangular parallelepiped housing. The length of the cell stack 101 in the left-right direction is longer than the length in the up-down direction. For convenience Figure 1 FIG. 3 shows a single power generation cell 1.

[0025] 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 electrodes; and separators 3, 3 disposed on the front and rear sides of the UEA 2 to sandwich the UEA 2. The UEA 2 and the separators 3 are alternately arranged in the front-rear direction. The UEA 2 may also be referred to as a membrane electrode structure or a membrane electrode member.

[0026] Figure 2 FIG. 4 is a main part cross-sectional view of the central portion of the cell stack 101 in the left-right direction (a cross-sectional view taken along the line II-II of Figure 1 FIG. 4). As Figure 2 shown in FIG. 5, the separator 3 has a pair of front and rear metal thin plates with a corrugated cross section, namely a front plate 3F and a rear plate 3R. The front plate 3F extends in the up-down, left-right directions and has a front surface 3Fa and a rear surface 3Fb. The rear plate 3R extends in the up-down, left-right directions and has a front surface 3Ra and a rear surface 3Rb. The outer peripheries between the rear surface 3Fb of the front plate 3F and the front surface 3Ra of the rear plate 3R facing each other are joined by welding or the like. Thus, the front plate 3F and the rear plate 3R are integrally joined. 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.

[0027] Inside the partition plate 3 enclosed by the front plate 3F and the rear plate 3R, that is, between the rear surface 3Fb of the front plate 3F and the front surface 3Ra of the rear plate 3R, a cooling flow path PAw for the cooling medium to flow is formed. 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 3Fa and rear surface 3Rb) of the partition plate 3 facing the UEA2 are formed into uneven shapes by stamping or the like, so that a gas flow path is formed between the partition plate 3 and the UEA2. More specifically, the partition plate 3 has a pair of front and rear convex portions 31 protruding toward the UEA2 and a pair of front and rear concave portions 32 connected to the pair of front and rear convex portions 31 to form a concave shape.

[0028] A pair of front and rear convex portions 31 are in contact with the front surface 2a and the rear surface 2b of the UEA2. When assembling the fuel cell stack 100, a compressive load F is applied to the cell laminate 101 in the front-rear direction, and after the assembly of the fuel cell stack 100 is completed, the compressive load F is maintained. Therefore, a prescribed surface pressure caused by the compressive load F acts on the UEA2 in the front-rear direction via the convex portion 31.

[0029] Between the front surface 2a of the UEA2 and the rear plate 3R of the partition plate 3 facing the front surface 2a, an anode flow path PAa for the fuel gas (anode gas) to flow is formed by using the concave portion 32. Between the rear surface 2b of the UEA2 and the front plate 3F of the partition plate 3 facing the rear surface 2b, a cathode flow path PAc for the oxidant gas (cathode gas) to flow is formed by using the concave portion 32. The fuel gas is a gas containing hydrogen, and for example, hydrogen gas can be used. The oxidant gas is a gas containing oxygen, and for example, air can be used. Sometimes, the fuel gas and the oxidant gas are not distinguished and are collectively referred to as reaction gases.

[0030] Figure 3 It is a perspective view showing the schematic structure of the UEA2. As Figure 3 shown, the UEA2 has a substantially rectangular membrane electrode assembly 20 (Membrane Electrode Assembly, hereinafter referred to as MEA) and a frame 21 supporting the MEA20. As Figure 2 shown in the detailed view of part A of, the MEA20 has an electrolyte membrane 23, an anode electrode 24 provided on the front surface 231 of the electrolyte membrane 23, and a cathode electrode 25 provided on the rear surface 232 of the electrolyte membrane 23.

[0031] The electrolyte membrane 23 is, for example, a solid polymer electrolyte membrane, and a thin film of a perfluorosulfonic acid polymer containing moisture can be used. It is not limited to fluorine-based electrolyte membranes, and hydrocarbon-based electrolyte membranes can also be used.

[0032] The anode electrode 24 has an electrode catalyst layer 241 formed on the front surface 231 of the electrolyte membrane 23 and serving as a reaction field for the electrode reaction, and a gas diffusion layer 242 provided on the front surface of the electrode catalyst layer 241 for diffusing and supplying the fuel gas. An intermediate layer (base layer) can also be provided between the electrode catalyst layer 241 and the gas diffusion layer 242.

[0033] The cathode electrode 25 has an electrode catalyst layer 251 formed on the rear surface 232 of the electrolyte membrane 23 and serving as a reaction field for the electrode reaction, and a gas diffusion layer 252 provided on the rear surface of the electrode catalyst layer 251 for diffusing and supplying the oxidant gas. An intermediate layer (base layer) can also be provided between the electrode catalyst layer 251 and the gas diffusion layer 252.

[0034] In the anode electrode 24, the fuel gas (hydrogen) supplied via the anode flow channel PAa is ionized by the action of the catalyst and moves through the electrolyte membrane 23 to the cathode electrode side. The electrons generated at this time pass through the external circuit and are taken out as electric energy. In the cathode electrode 25, the oxidant gas (oxygen) supplied via the cathode flow channel PAc reacts with the hydrogen ions introduced from the anode electrode 24 and the electrons that have moved from the anode electrode 24 to generate water. The generated water (referred to as the generated water) gives appropriate humidity to the electrolyte membrane 23, and the remaining water is discharged to the outside of the UEA2 along with the flow of the gas. The generated water on the cathode side also flows to the anode side through back-diffusion via the electrolyte membrane 23. Therefore, the generated water exists in both the anode flow channel PAa and the cathode flow channel PAc.

[0035] As Figure 3 shown, the frame 21 is a thin plate having a substantially rectangular shape and is made of an insulating resin, rubber, etc. 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.

[0036] On the left side of the opening 21a of the frame 21, three through-holes 211 to 213 that penetrate the frame 21 in the front-rear direction are arranged in the up-down direction. On the right side of the opening 21a, three through-holes 214 to 216 that penetrate the frame 21 in the front-rear direction are arranged in the up-down 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 to this.

[0037] As Figure 1As shown, partition plates 3 are provided in front of and behind the UEA2, and through holes 301 to 306 that penetrate the partition plate 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 301 to 306 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 301 to 306 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. The flow channels PA1 to PA6 are connected to a manifold outside the fuel cell stack 100.

[0038] Although not shown in the figure, the front and rear end units 102 of the battery laminate 101 each have a plurality of plates that are overlapped and arranged in the front-rear direction. That is, the end unit 102 has a terminal plate that is adjacently arranged to the battery laminate 101, an insulating plate that is arranged on the outer side in the front-rear direction of the terminal plate, and an end plate that is arranged on the outer side in the front-rear direction of the insulating plate.

[0039] The terminal plate is a substantially rectangular plate-like member made of metal and has a terminal portion for taking out the electric power generated by the electrochemical reaction in the battery laminate 101. The insulating plate is a substantially rectangular plate-like member made of a non-conductive resin or rubber, and electrically insulates the terminal plate and the end plate. The end plate is a plate-like member made of metal or resin made of a high-strength structure.

[0040] The rear end unit 102 is a wet-side end unit through which the reaction gas and the cooling medium pass, and the front end unit 102 is a dry-side end unit through which the reaction gas and the cooling medium do not pass. In the rear end unit 102, a plurality of through holes 102a to 102f that penetrate the end unit 102 in the front-rear direction are provided at positions corresponding to the through holes 211 to 216 and 301 to 306 of the battery laminate 101. For convenience, the through holes 102a to 102f are all shown in a substantially rectangular shape, but the shape of the through holes 102a to 102f is not limited to this.

[0041] A fuel gas tank storing high-pressure fuel gas is connected to the through hole 102a via an ejector, an injector, etc., and fuel gas (anode gas) is supplied to the fuel cell stack 100 along the flow channel PA1 indicated by the solid line via the through hole 102a. The fuel gas is introduced into the anode flow channel PAa between the UEA2 and the rear plate 3R of the partition plate 3 via the through holes 211 and 301. The fuel gas after passing through the anode flow channel PAa, that is, the fuel exhaust (anode exhaust gas), is discharged from the through hole 102f along the flow channel PA6 indicated by the solid line via the through holes 216 and 306. It should be noted that the through hole 102a is provided on the upper side in the up-down direction (the side opposite to the gravity direction) than the through hole 102f.

[0042] A compressor for supplying an oxidant gas is connected to the through-hole 102d. The oxidant gas (cathode gas) compressed by the compressor is supplied to the fuel cell stack 100 via the through-hole 102d along the flow path PA4 indicated by the dashed line. The oxidant gas is introduced into the cathode flow path PAc between the UEA2 and the front plate 3F of the separator 3 via the through-holes 214 and 304. The oxidant gas after passing through the cathode flow path PAc, i.e., the oxidant exhaust gas (cathode exhaust gas), is discharged from the through-hole 102c along the flow path PA3 indicated by the dashed line via the through-holes 213 and 303.

[0043] A pump for supplying a cooling medium is connected to the through-hole 102e. The cooling medium is supplied to the fuel cell stack 100 via the through-hole 102e along the flow path PA5 indicated by the single-dot chain line. The cooling medium is introduced into the cooling flow path PAw between the front plate 3F and the rear plate 3R of the separator 3 via the through-holes 215 and 305. The cooling medium after passing through the cooling flow path PAw is discharged from the through-hole 102b along the flow path PA2 indicated by the single-dot chain line via the through-holes 212 and 302. The discharged cooling medium is cooled by heat exchange in the radiator and then supplied to the fuel cell stack 100 again via the through-hole 102e. The above is the schematic structure of the fuel cell stack 100.

[0044] The structure of the separator 3 will be described in more detail. Figure 4 It is a rear view of the separator 3 (a view observed from the rear). That is, Figure 4 It is a view showing the rear surface 3Rb of the separator 3 facing the anode electrode 24 on the front surface 2a of the UEA2 ( Figure 2 ). The point P in the figure is the midpoint of the separator 3 in the left-right direction and the midpoint in the up-down direction, which is called the center point. Figure 4 The left-right direction and the up-down direction respectively correspond to the length direction and the short side direction of the separator 3.

[0045] In Figure 4 , the region AR1 of the separator 3 facing the MEA20 of the UEA2, i.e., the region facing the power generation surface, is called the active region of the separator 3, and the region AR2 other than the active region is called the non-active region. As Figure 2 , 4 shows, in the active region AR1 of the separator 3, although part of the illustration is omitted, a plurality of convex portions 31 are protruded rearward at equal intervals in the up-down direction over substantially the entire region in this region ( Figure 2 ). The plurality of convex portions 31 respectively extend in a meandering manner in the left-right direction, and recesses 32 are provided between the convex portions 31 adjacent in the up-down direction ( Figure 2 ). An anode flow path PAa is formed between the plurality of recesses 32 and the front surface 2a of the MEA20.

[0046] As Figure 4As shown, a plurality of sealing projections, i.e., metal projection seals, which protrude rearward toward the frame 21, are provided on the rear surface 3Rb of the partition plate 3 (rear plate 3R). The plurality of projections include an outer projection 331, an inner projection 332, and an end projection 333.

[0047] The outer projection 331 extends along the peripheral edge of the rear plate 3R so as to surround the entire through holes 301 to 306, and is generally rectangular in shape as a whole. The end projections 333 are provided in a number corresponding to the number of the through holes 301 to 306. The plurality of end projections 333 are each generally rectangular in shape and individually surround the plurality of through holes 301 to 306. The inner projection 332 is provided inside the outer projection 331. More specifically, the inner projection 332 extends in a zigzag shape via the outer sides in the left-right direction of the end projections 333 around the through holes 301, 303, 304, 306, and via the inner sides in the left-right direction of the end projections 333 around the through holes 302, 305. The end projections 333 around the through holes 302, 305 are located between the outer projection 331 and the inner projection 332.

[0048] A plurality of generally cylindrical embossments 341 that protrude in the front-rear direction are provided on both sides in the left-right direction of the active region AR1 of the partition plate 3. The convex portions 31, the concave portions 32, the metal projection seals, etc. are formed by stamping the rear plate 3R.

[0049] Although not shown, a plurality of convex portions 31, concave portions 32, metal projection seals (outer projection 331, inner projection 332, end projection 333), etc. are also formed on the front surface 3Fa of the partition plate 3 (front plate 3F) by stamping the front plate 3F. Thus, a cathode flow channel PAc is formed between the plurality of concave portions 32 and the rear surface 2b of the MEA 20.

[0050] Figure 5 is Figure 1 A main part cross-sectional view of the rear end portion of the fuel cell stack 100 including the flow channel PA1 for supplying fuel gas (a cross-sectional view taken along the Figure 1 section line V-V). As Figure 5 shown, the battery stack 101 has a plurality of power generation cells 1 as power generation bodies and dummy cells 10 as non-power generation bodies. The dummy cells 10 are sandwiched between the last power generation cell 1 (for convenience, referred to as the rear end power generation cell 1a) and the rear end unit 102. The dummy cells 10 can also be sandwiched between the foremost power generation cell 1 and the front end unit 102.

[0051] Dummy battery 10 has a dummy component 11 corresponding to UEA2 and dummy partitions 12 disposed on both sides in the front-rear direction of the dummy component 11. The structure of the dummy partitions 12 is the same as that of the partitions 3 of the power generation battery 1. Therefore, through holes 301 to 306 having the same structure as the partitions 3 are formed in the dummy partitions 12.

[0052] The dummy component 11 has a dummy frame 210 and a dummy joint body 200. The dummy frame 210 is configured to be the same as the frame 21 of the power generation battery 1 except that the structures (sizes) of the through holes 211 and 214 for supplying reaction gas are different. Therefore, through holes 211a to 216a and an opening 21a the same as the through holes 211 to 216 and the opening 21a of the frame 21 are provided in the dummy frame 210.

[0053] The dummy joint body 200 is a conductive plate and electrode joint body provided so as to cover the opening 21a ( Figure 3 ) of the dummy frame 210. The difference between the dummy battery 10 and the power generation battery 1 is that it does not have an electrolyte membrane 23 and power generation does not occur in the dummy battery 10. By disposing the dummy battery 10 adjacent to the end unit 102 in this way, the dummy battery 10 functions as a heat insulating layer, and it is possible to suppress a temperature drop of the power generation battery 1. It should be noted that the dummy frame 210 and the dummy joint body 200 may not be provided separately, but the plate of the dummy joint body 200 may be enlarged so that the plate of the dummy joint body 200 has the function of the dummy frame 210. In Figure 5 a single dummy battery 10 is disposed between the power generation battery 1 and the end unit 102, but a plurality of dummy batteries 10 may also be disposed.

[0054] In Figure 5 protruding portions for sealing (end protruding portions 333) protruding forward and backward from the front plate 3F and the rear plate 3R of the partition 3 and the dummy partition 12 are shown. A sealing material 13 made of an elastic constituent material such as rubber or resin material is fixed to the surface of the end protruding portion 333. Although not shown, the sealing material 13 is fixed not only to the surface of the end protruding portion 333 but also to the surfaces of the outer protruding portion 331 ( Figure 4 ) and the inner protruding portion 332 ( Figure 4 ). By applying a pushing force in the front-rear direction to the sealing material 13, it is possible to seal the contact surfaces between the partition 3 and the frame 21 and between the dummy partition 12 and the dummy frame 210 and the end unit 102.

[0055] As Figure 4As shown, a plurality of channel portions 41 are provided around the through-hole 301 of the partition plate 3 for inflow of fuel gas in a manner that traverses the end raised portion 333. For example, the channel portions 41 are provided in a manner that traverses the right end portion of the end raised portion 333 in the left-right direction and the lower end portion of the end raised portion 333 in the up-down direction.

[0056] Figure 6A is a cross-sectional view showing the structure of the channel portion 41 near the through-hole 301 (a cross-sectional view taken along the Figure 4 A-A line shown). As Figure 6A shown, the channel portion 41 is provided in a convex shape toward the front on the front plate 3F, and the channel portion 41 is provided in a convex shape toward the rear on the rear plate 3R. The protruding amount of the channel portion 41 in the front-rear direction is smaller than the protruding amount of the raised portion 333 in the front-rear direction. Although not shown, the cross-section of the channel portion 41 is substantially rectangular or substantially trapezoidal, and a communication flow path PA11 is formed between the front and rear channel portions 41, 41.

[0057] The left end of the channel portion 41 is located at the periphery of the through-hole 301, and the left end of the communication flow path PA11 faces the through-hole 301 and is open. A tapered portion 411 is provided at the right end portion of the channel portion 41, which is on the right side of the end raised portion 333, such that the protruding amount gradually decreases toward the right. At the right end of the channel portion 41, the protruding amount in the front-rear direction becomes 0, and the communication flow path PA11 is closed. A fuel gas outlet 410 is provided in the tapered portion 411 of the rear plate 3R. Thus, the through-hole 301 and the anode flow path PAa behind the rear plate 3R are connected via the communication flow path PA11 and the outlet 410. Therefore, as Figure 6A shown by the arrow, the fuel gas flowing through the through-hole 301 can be supplied to the anode flow path PAa via the communication flow path PA11 and the outlet 410.

[0058] As Figure 4 shown, a plurality of channel portions 42 are provided around the through-hole 306 of the partition plate 3 in a manner that traverses the end raised portion 333. Although not shown, the channel portion 42 is configured in the same manner as the Figure 6A channel portion 41. That is, the channel portion 41 and the channel portion 42 are in a symmetric shape or substantially symmetric shape with respect to an axis (not shown) that extends in the front-rear direction through the Figure 4 center point P. Therefore, a fuel gas inlet 420 is provided in the tapered portion at the left end of the channel portion 42 on the rear plate 3R. Thus, the fuel gas flowing through the anode flow path PAa is introduced into the through-hole 306 via the inlet 420 and the communication flow path PA11 inside the channel portion 42.

[0059] At the end convex portion 333 around the through hole 304 of the partition plate 3 for the inflow of the oxidant gas, a plurality of channel portions 44 are also provided so as to cross the end convex portion 333. For example, the channel portions 44 are provided so as to cross the left end portion of the end convex portion 333 in the left-right direction and the lower end portion of the end convex portion 333 in the up-down direction.

[0060] Figure 6B It is a cross-sectional view showing the structure of the channel portion 44 near the through hole 304 (a cross-sectional view taken along the Figure 4 section line B-B). As Figure 6B shown, the channel portion 44 is provided in a convex shape toward the front on the front plate 3F, and the channel portion 44 is provided in a convex shape toward the rear on the rear plate 3R. The protruding amount of the channel portion 44 in the front-rear direction is smaller than the protruding amount of the convex portion 333 in the front-rear direction. Although not shown, the cross-section of the channel portion 44 is substantially rectangular or substantially trapezoidal, and a communication flow path PA12 is formed between the front and rear channel portions 44, 44.

[0061] The right end of the channel portion 44 is located at the periphery of the through hole 304, and the right end surface of the communication flow path PA12 faces the through hole 304. A tapered portion 441 is provided at the left end portion of the channel portion 44, which is to the left of the end convex portion 333, such that the protruding amount gradually decreases toward the left. At the left end of the channel portion 44, the protruding amount in the front-rear direction becomes 0, and the communication flow path PA12 is closed. An outlet 440 for the oxidant gas is provided in the tapered portion 441 of the front plate 3F. Thus, the through hole 304 and the cathode flow path PAc in front of the front plate 3F are communicated via the communication flow path PA12 and the outlet 440. Therefore, as Figure 6B shown by the arrow, the oxidant gas flowing through the through hole 304 can be supplied to the cathode flow path PAc via the communication flow path PA12 and the outlet 440.

[0062] As Figure 4 shown, a plurality of channel portions 43 are provided in the end convex portion 333 around the through hole 303 of the partition plate 3 so as to cross the end convex portion 333. Although not shown, the channel portion 43 is configured in the same manner as the Figure 6B channel portion 44. That is, the channel portion 43 and the channel portion 44 are in a symmetric shape or a substantially symmetric shape with respect to an axis (not shown) extending in the front-rear direction through the Figure 4 center point P. Therefore, an inlet 430 for the fuel gas is provided in the tapered portion at the right end portion of the channel portion 43 of the front plate 3F. Thus, the oxidant gas flowing through the cathode flow path PAc is introduced into the through hole 303 via the inlet 430 and the communication flow path PA12 inside the channel portion 43.

[0063] Note that the configurations (number, position, shape, etc.) of the channel portions 41 and 44 that connect the flow paths PA1 and PA4 for gas supply to the anode flow path PAa and the cathode flow path PAc, and the channel portions 42 and 43 that connect the flow paths PA3 and PA6 for gas discharge to the anode flow path PAa and the cathode flow path PAc are not limited to those described above. For example, more channel portions 41 and 44 may be provided downward or obliquely downward.

[0064] As Figure 5 shown, the axis CL1 of the center of the through-hole 211 of the frame 21 in the vertical and horizontal directions and the axis CL2 of the center of the through-hole 211a of the dummy frame 210 in the vertical and horizontal directions are located on the same straight line extending in the front-rear direction. The through-holes 211 and 211a of the frame 21 and the dummy frame 210 are smaller than the through-hole 301 of the partition plate 3 and the dummy partition plate 12. Therefore, the frame 21 and the dummy frame 210 protrude inward (toward the axes CL1 and CL2) compared to the partition plate 3 and the dummy partition plate 12.

[0065] For convenience, in Figure 5 the through-hole 211 and the through-hole 211a are shown in the same shape and size. Note that having the same size means that the opening areas of the through-holes 211 and 211a are the same as each other. In Figure 5 since the axes CL1 and CL2 are on the same straight line and the shapes of the through-holes 211 and 211a are the same as each other, the extended surface obtained by extending the opening surface (the inner peripheral surface of the through-hole 211a) along the edge of the through-hole 211a forward coincides with the opening surface (the inner peripheral surface of the through-hole 211) of the through-hole 211.

[0066] In this way, when the through-hole 211a of the dummy battery 10 (dummy frame 210) and the through-hole 211 of the power generation battery 1 (frame 21) are set to the same shape and size, the following problem occurs. That is, in this case, the liquid water (generated water, condensed water) that flows into the interior of the battery stack 101 together with the fuel gas via the through-hole 102a of the end unit 102 sometimes skips the through-hole 211a of the dummy battery 10 and reaches the power generation battery 1 as Figure 5 indicated by the arrow.

[0067] The liquid water that reaches the power generation battery 1 is introduced into the anode flow path PAa facing the power generation surface of the UEA2 along the flow of the fuel gas via the communication flow path PA11 inside the channel portion 41 ( Figure 6A ). As a result, it is possible to hinder the electrochemical reaction on the power generation surface, making the power generation performance unstable and the power generation performance deteriorate. In this regard, not only for the flow path PA1 for fuel gas supply, but also for the flow path PA4 for oxidant gas supply ( Figure 1), also becomes a problem. That is, the liquid water in the flow path PA4 is introduced into the cathode flow path PAc facing the power generation surface of the UEA2 along the flow of the oxidant gas through the communication flow path PA12 inside the channel portion 44, and it is possible that the power generation performance becomes unstable and the power generation performance decreases. Figure 6B ), and it is possible that the power generation performance becomes unstable and the power generation performance decreases when it is introduced into the cathode flow path PAc facing the power generation surface of the UEA2 along the flow of the oxidant gas.

[0068] Therefore, the fuel cell stack 100 of the present embodiment is configured as follows to obtain stable power generation performance by providing a liquid water inflow suppression portion for suppressing the introduction of liquid water flowing into the flow paths PA1 and PA4 into the power generation surface.

[0069] Figure 7A is a diagram schematically showing a first example of the liquid water inflow suppression portion, that is, the structure of the first liquid water inflow suppression portion 51, and is the same as Figure 5 and is a cross-sectional view including the flow path PA1 for supplying fuel gas. Figure 7B is a view of the flow path PA1 observed from the rear ([[]] Figure 7A VIIB direction view). Although not shown, the first liquid water inflow suppression portion 51 is also provided in the flow path PA4 for supplying oxidant gas in the same manner.

[0070] As Figure 7A 、 7B shown, in the first liquid water inflow suppression portion 51, the through hole 211a of the dummy frame 210 is formed larger than the through hole 211 of the frame 21 and larger than the through hole 102a of the end unit 102 (especially larger in the vertical direction). The through hole 211 of the frame 21 and the through hole 102a of the end unit 102 are the same size. The axis CL1 ([[]] Figure 5 ) of the through hole 211 and the axis CL2 ([[]] Figure 5 ) of the through hole 211a are located on the same straight line.

[0071] In the first liquid water inflow suppression portion 51, the edge portion 217 of the through hole 211 of the frame 21 protrudes inward in the entire circumference compared to the edge portion 217a of the through hole 211a of the dummy frame 210. Therefore, the extended surface 211b (double-dot chain line) obtained by extending the opening surface of the through hole 211a forward is located on the outer side (the opposite side of the axes CL1 and CL2) compared to the opening surface of the through hole 211, and the extended surface 211b touches the frame 21 of the rear end power generation cell 1a. The edge portion 217 of the through hole 211 of the frame 21 constitutes a protruding portion that protrudes inward compared to the through hole 211a. The lower protruding portion is particularly referred to as the lower protruding portion 218.

[0072] The first liquid water inflow suppression portion 51 operates as follows. When liquid water flows into the flow path PA1 through the through hole 102a of the end unit 102, as Figure 7AAs indicated by the arrow, a part of the liquid water passing through the through-hole 211a of the dummy frame 210 collides with the edge portion 217 (protrusion) of the through-hole 211. More specifically, since the liquid water tends to flow downward due to gravity, a part of the liquid water passing through the through-hole 211a collides with the lower protrusion 218. Therefore, as Figure 7B shown by the shading, the flow of the liquid water is intercepted by the lower protrusion 218.

[0073] The intercepted liquid water flows downward along the communication flow path PA11 ( Figure 6A ) of the dummy partition 12 and the front surface of the dummy component 11. Furthermore, it is discharged to the outside of the battery laminate 101 via the flow path PA6 ( Figure 1 ) for discharging the fuel gas. Thereby, it is possible to suppress the liquid water in the flow path PA1 from passing through the through-hole 211 of the frame 21 and being introduced into the anode flow path PAa of the power generation battery 1, and stable power generation performance can be obtained.

[0074] Figure 8 FIG. is a diagram schematically showing a second example of the liquid water inflow suppression portion, that is, the structure of the second liquid water inflow suppression portion 52, and is a cross-sectional view including the flow path PA1 for supplying fuel gas and the flow path PA6 for discharging fuel gas. Although not shown, the second liquid water inflow suppression portion 52 is similarly provided in the flow path PA4 for supplying oxidant gas and the flow path PA3 for discharging oxidant gas.

[0075] As Figure 8 shown, the structure (the sizes of the through-holes 211 and 211a) of the flow path PA1 for supplying fuel gas is the same as that of the first liquid water inflow suppression portion 51. Therefore, the through-hole 211a of the dummy frame 210 of the flow path PA1 is larger than the through-hole 211 of the frame 21 in the vertical direction.

[0076] In contrast, the through-hole 216a of the dummy frame 210 in the discharge flow path PA6 is formed to be smaller than the through-hole 216 of the frame 21 (especially in the vertical direction) and smaller than the through-hole 102f of the end unit 102 (especially in the vertical direction). The through-hole 216 of the frame 21 and the through-hole 102f of the end unit 102 are the same size. The axes (not shown) of the through-holes 216 and 216a extending in the front-rear direction are located on the same straight line.

[0077] The second liquid water inflow suppression portion 52 operates as follows. When the liquid water flows into the flow path PA1 via the through-hole 102a of the end unit 102, as Figure 8As shown by the arrow, a part of the liquid water passing through the through-hole 211a of the dummy frame 210 collides with the edge portion 217 (mainly the lower protruding portion 218) of the through-hole 211. The flow velocity and pressure of the fuel gas in the region A indicated by the double-dot chain line on the inlet side of the flow path PA1 and the region B indicated by the double-dot chain line on the outlet side of the flow path PA4 are compared. On the inlet side, the through-hole 211a is larger than the through-hole 211, so the flow velocity is low and the pressure becomes high. On the other hand, on the outlet side, the through-hole 216a is smaller than the through-hole 216, so the flow velocity is high and the pressure becomes low. Thus, the pressure difference between the region A and the region B increases, so the flow of the liquid water from the region A to the region B is promoted, and the liquid water in the flow path PA1 can be efficiently introduced into the flow path PA6.

[0078] Figure 9A FIG. is a diagram schematically showing a third example of the liquid water inflow suppression portion, that is, the structure of the third liquid water inflow suppression portion 53. Figure 9B FIG. is a view of the flow path PA1 observed from the rear ( Figure 9A IXB direction view). Although not shown, the third liquid water inflow suppression portion 53 is also provided in the flow path PA4 for supplying the oxidant gas in the same manner.

[0079] As Figure 9A 、 9B shown, in the third liquid water inflow suppression portion 53, contrary to the first liquid water inflow suppression portion 51, the through-hole 211a of the dummy frame 210 is formed smaller than the through-hole 211 of the frame 21 (especially smaller in the vertical direction) and smaller than the through-hole 102a of the end unit 102. The through-hole 211 of the frame 21 has the same size as the through-hole 102a of the end unit 102. The axis CL1 ( Figure 5 ) of the through-hole 211 and the axis CL2 ( Figure 5 ) of the through-hole 211a are located on the same straight line.

[0080] In the third liquid water inflow suppression portion 53, the edge portion 217a of the through-hole 211a in the dummy frame 210 protrudes inward more than the edge portion 217 of the through-hole 211 in the frame 21 over the entire circumference. Therefore, the extended surface 211b obtained by extending the opening surface of the through-hole 211a forward is located more inward than the opening surface of the through-hole 211. The edge portion 217a of the through-hole 211a of the dummy frame 210 constitutes a protruding portion that protrudes inward more than the through-hole 211. The lower protruding portion is particularly referred to as the lower protruding portion 218a.

[0081] The third liquid water inflow suppression portion 53 operates as follows. When the liquid water flows into the flow path PA1 via the through-hole 102a of the end unit 102, as Figure 9A shown by the arrow, a part of the liquid water collides with the edge portion 217a (mainly the lower protruding portion 218a) of the through-hole 211a. Therefore, as Figure 9BAs shown by the shaded area, the flow of liquid water is intercepted at the lower protruding portion 218a.

[0082] The intercepted liquid water flows downward along the communication flow path PA11 of the dummy partition 12 ( Figure 6A ) and the front surface of the end unit 102. Further, it is discharged to the outside of the battery laminate 101 via the flow path PA6 for discharging fuel gas ( Figure 1 ). Thus, it is possible to prevent the liquid water in the flow path PA1 from passing through the through hole 211a of the dummy frame 210 and being introduced into the anode flow path PAa of the power generation cell 1, and stable power generation performance can be obtained.

[0083] In the above-described first liquid water inflow inhibition portion 51 and second liquid water inflow inhibition portion 52, a single dummy cell 10 ( Figure 7A , Figure 7B , Figure 8 ) is disposed between the power generation cell 1 and the end unit 102, but a plurality (for example, two) of dummy cells 10 may be disposed. In this case, the through hole 211a of the front-side dummy frame 210 may be set to the same size as the through hole 211 of the frame 21 located in front of it and smaller than the through hole 211a of the rear-side dummy frame 210.

[0084] Thus, a part of the liquid water that has passed through the through hole 211a of the rear-side dummy frame 210 can collide with the edge portion 217a around the through hole 211a of the front-side dummy frame 210. As a result, similar to the third liquid water inflow inhibition portion 53, it is possible to prevent the liquid water from flowing forward across the through hole 211a of the dummy frame 210 (rear-side dummy frame 210).

[0085] Figure 10 It is a cross-sectional view showing a modified example of the through holes 102a and 102d for supplying reaction gas of the end unit 102. In Figure 10 the modified example, the opening surfaces (especially the lower opening surface) of the through holes 102a and 102d of the end unit 102 are inclined downward so that the opening area gradually increases forward. That is, an inclined surface 102g is provided on the opening surfaces (inner peripheral surfaces of the through holes 102a and 102d). Thus, the liquid water flows obliquely downward along the inclined surface 102g, so that the flow of the liquid water toward the front-side dummy cell 10 is promoted, and the liquid water can be efficiently introduced into the flow paths PA3 and PA6 for reaction exhaust via the dummy cell 10.

[0086] Adopting the present embodiment can achieve the following effects.

[0087] (1) The fuel cell stack 100 includes: a cell laminate 101 having a plurality of power generation cells 1 as power generation bodies laminated in the front-rear direction and dummy cells 10 as non-power generation bodies arranged adjacent to the rear-end power generation cell 1a located at the rear end of the plurality of power generation cells 1. Flow channels PA1, PA4 for supplying reaction gas and flow channels PA3, PA6 for discharging reaction gas are respectively provided and extend in the front-rear direction, and gas flow channels (anode flow channel PAa, cathode flow channel Pac) that connect flow channel PA1 and flow channel PA6 and flow channel PA4 and flow channel PA3 are provided; and an end unit 102 arranged adjacent to the dummy cell 10 and provided with gas supply ports (through holes 102a, 102d) communicating with flow channels PA1, PA4 for gas supply and gas discharge ports (through holes 102c, 102f) communicating with flow channels PA3, PA6 for gas discharge ( Figures 1 to 5 ). Through holes 211 (first communication holes) constituting flow channels PA1, PA4 for gas supply are formed in the rear-end power generation cell 1a (frame 21), and through holes 211a (second communication holes) constituting flow channels PA1, PA4 for gas supply are formed in the dummy cell 10 (dummy frame 210)( Figures 7A to 9B ). The fuel cell stack 100 has any one of a first liquid water inflow inhibition part 51, a second liquid water inflow inhibition part 52, and a third liquid water inflow inhibition part 53, and the through holes 211 and 211a are arranged such that the extended surface 211b of the through hole 211a extending in the front-rear direction with the opening surface of the through hole 211a facing the through hole 211 is not coincident with the opening surface of the through hole 211( Figure 7A 、 Figure 8 、 Figure 9A ).

[0088] With this structure, the liquid water (generated water, condensed water) flowing into flow channels PA1, PA4 for gas supply together with the reaction gas can flow through the inside of the dummy cell 10 to flow channels PA3, PA6 for gas discharge before reaching the power generation cell 1. As a result, the supply of liquid water to the power generation cell 1 can be suppressed, and stable power generation performance can be obtained.

[0089] (2) In the first liquid water inflow inhibition part 51 and the second liquid water inflow inhibition part 52, the through hole 211 of the frame 21 is smaller than the through hole 211a of the dummy frame 210( Figure 7A 、 Figure 7B 、 Figure 8 ). Thus, the liquid water flowing into flow channels PA1, PA4 for gas supply is intercepted at the edge 217 of the through hole 211 of the frame 21 of the rear-end power generation cell 1a, and the inflow of liquid water exceeding the through hole 211 into flow channels PA1, PA4 can be suppressed.

[0090] (3) In the second liquid water inflow inhibition part 52, through holes 213 and 216 ([ Figure 3 ) that form flow paths PA3 and PA6 for gas discharge are formed in the rear end power generation battery 1a (frame 21). Through holes 216a ([ Figure 8 ) that are smaller than the through holes 213 and 216 and form flow paths PA3 and PA6 for gas discharge are formed in the dummy battery 10 (dummy frame 210). Thereby, the pressure difference between the region A inside the through hole 211a of the dummy frame 210 and the region B inside the through hole 216a becomes larger, and the liquid water before reaching the power generation battery 1 easily flows toward the flow paths PA3 and PA6 for gas discharge.

[0091] (4) In the third liquid water inflow inhibition part 53, the through hole 211 of the frame 21 is larger than the through hole 211a of the dummy frame 210 ([ Figure 9A 、 Figure 9B ). Thereby, the liquid water flowing into the flow paths PA1 and PA4 for gas supply is intercepted at the edge part 217a of the through hole 211a of the dummy frame 210, and it is possible to inhibit the liquid water from flowing into the flow paths PA1 and PA4 exceeding the through hole 211.

[0092] (5) In the through holes 102a and 102d (gas supply ports) for gas supply of the end unit 102, an inclined surface 102g with a downward slope is provided such that the opening area gradually increases in the gas flow direction ([ Figure 10 ). Thereby, the liquid water flows obliquely downward along the inclined surface 102g, so that the flow of the liquid water toward the front-side dummy battery 10 is promoted, and the liquid water can be efficiently introduced into the exhaust flow paths PA3 and PA6 via the dummy battery 10.

[0093] (6) The stacking direction of the fuel cell stack 100 is substantially horizontal (front-rear direction)([ Figure 1 ). The vertical position of the lower end part of the through hole 211 of the frame 21 and the vertical position of the through hole 211a of the dummy frame 210 are different from each other ([ Figure 7A 、 Figure 7B 、 Figure 8 、 Figure 9A 、 Figure 9B ). Thereby, the reaction gas hits the edge part 217 of the frame 21 of the rear end power generation battery 1a or the edge part 217a of the dummy frame 210 of the dummy battery 10, and the liquid water contained in the reaction gas can be separated well.

[0094] (7) One of the edge parts 217 and 217a of the through hole 211 of the frame 21 and the through hole 211a of the dummy frame 210 has a protruding part that protrudes into the opening area of the other of the through hole 211 and the through hole 211a when observing the through holes 211 and 211a along the front-rear direction ([ Figure 7B 、 Figure 9B) Thus, a part of the reaction gas flowing into the flow paths PA1 and PA4 for gas supply hits the protruding portions (edge portions 217 and 217a) before reaching the power generation cell 1, and the flow of liquid water into the power generation cell 1 can be suppressed.

[0095] (8) The fuel cell stack 100 has lower protruding portions 218 and 218a provided on the lower side of the edge portions at one lower end of the through holes 211 and 211a as a part of the protruding portions ( Figure 7B , Figure 9B ). Thus, the liquid water flowing through the flow paths PA1 and PA4 for gas supply can be intercepted well.

[0096] The above-described embodiment can be deformed into various forms. Several modification examples will be described below. In the above-described embodiment, the through hole 211a (second communication hole) of the dummy frame 210 in the gas supply flow paths PA1 and PA4 is set to be larger or smaller in the vertical direction than the through hole 211 (first communication hole) of the frame 21, but the sizes (opening areas) can also be kept the same as each other, and the shapes of the through holes 211 and 211a can be made different from each other. It is also possible to keep the sizes and shapes the same as each other and make the positions of the axes CL1 and CL2 of the through holes 211 and 211a different from each other. That is, as long as the second communication hole is arranged such that the extended plane where the opening of the second communication hole extends toward the first communication hole does not coincide with the opening plane of the first communication hole, the structures of the first communication hole and the second communication hole are not limited to those described above.

[0097] In the above-described embodiment ( Figure 8 ), although the through hole 216a (fourth communication hole) of the dummy frame 210 in the gas discharge flow paths PA3 and PA6 is set to be smaller than the through hole 216 (third communication hole) of the frame 21, as long as the structure is formed such that the pressure in region B becomes smaller, the structures of the third through hole and the fourth through hole are not limited to those described above. In the above-described embodiment, the through holes 211 and 211a of the frame 21 and the dummy frame 210 are set to be smaller than the through hole 301 of the partition plate 3 and the dummy partition plate 12, the through hole 211 of the frame 21 is configured as the first communication hole of the power generation cell 1, and the through hole 211a of the dummy frame 210 is configured as the second communication hole of the dummy cell 10. In this regard, each through hole can also be configured such that the through hole 301 of the partition plate 3 and the dummy partition plate 12 is set to be smaller than the through holes 211 and 211a of the frame 21 and the dummy frame 210, and the through hole 301 of the partition plate 3 becomes the first communication hole, and the through hole 301 of the dummy partition plate 12 becomes the second communication hole.

[0098] In the above-described embodiment, a battery laminate 101 is formed by laminating a plurality of single cells in the front-rear direction, but a battery laminate may also be formed by laminating a plurality of single cells in a specified direction other than the front-rear direction. In this case, it is preferable that the lamination direction (specified direction) is a substantially horizontal direction. In the above-described embodiment, similar to the separator 3, the dummy separator 12 adjacent to the end unit 102 is formed of a joined body of the front plate 3F and the rear plate 3R, but it may also be formed of a single plate (for example, the front plate 3F), and the configuration of the dummy cell 10 is not limited to the above. In the above-described embodiment, the through holes 211 and 211a of the flow path PA1 for supplying fuel gas are formed in a substantially rectangular shape, but they may also be formed to be convex downward.

[0099] One or more of the above-described embodiment and modification examples can be arbitrarily combined, and the modification examples can also be combined with each other.

[0100] By adopting the present invention, it is possible to suppress the flow of liquid water contained in the reaction gas supplied through the gas supply port to the power generation cell and obtain stable power generation performance.

[0101] 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 disclosure scope 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) as power generation bodies laminated in a specified direction and dummy cells (10) as non-power generation bodies arranged adjacent to an end power generation cell (1a) at one end in the specified direction among the plurality of power generation cells (1), a gas supply flow path (PA1, PA4) for supplying reaction gas and a gas discharge flow path (PA3, PA6) for discharging reaction gas are respectively extended and provided along the specified direction, and a gas flow path (PAa, PA c) for connecting the gas supply flow path (PA1, PA4) and the gas discharge flow path (PA3, PA6) is provided; and An end unit (102) arranged adjacent to the dummy cell (10) and provided with a gas supply port (102a, 102d) communicating with the gas supply flow path (PA1, PA4) and a gas discharge port (102c, 102f) communicating with the gas discharge flow path (PA3, PA6), A first communication hole (211) forming the gas supply flow path (PA1, PA4) is opened in the end power generation cell (1a), A second communication hole (211a) forming the gas supply flow path (PA1, PA4) is opened in the dummy cell (10), The first communication hole (211) and the second communication hole (211a) are arranged such that the opening surface of the second communication hole (211a) faces the extended surface (211b) obtained by extending the first communication hole (211) in the specified direction and the opening surface of the first communication hole (211) do not coincide.

2. The fuel cell stack according to claim 1, characterized in that The first communication hole (211) is smaller than the second communication hole (211a).

3. The fuel cell stack according to claim 2, characterized in that Third communication holes (213, 216) forming the gas discharge flow path (PA3, PA6) are opened in the end power generation cell (1a), A fourth communication hole (216a) forming the gas discharge flow path (PA3, PA6) and smaller than the third communication holes (213, 216) is opened in the dummy cell (10).

4. The fuel cell stack according to claim 1, characterized in that The first communication hole (211) is larger than the second communication hole (211a).

5. The fuel cell stack according to any one of claims 1 to 4, characterized in that An inclined surface (102g) with a downward slope whose opening area gradually increases in the flow direction of the reaction gas is provided at the gas supply port (102a, 102d).

6. The fuel cell stack according to any one of claims 1 to 4, characterized in that The specified direction is a substantially horizontal direction, The vertical position of the lower end of the first communication hole (211) and the vertical position of the lower end of the second communication hole (211a) are different from each other.

7. The fuel cell stack according to any one of claims 1 to 4, characterized in that When observing the first communication hole (211) and the second communication hole (211a) along the specified direction, an edge portion of one of the first communication hole (211) and the second communication hole (211a) has a protruding portion that protrudes into the opening area of the other of the first communication hole (211) and the second communication hole (211a).

8. The fuel cell stack according to claim 7, wherein the specified direction is a substantially horizontal direction, the protruding portion is provided at an edge portion of a lower end of one of the first communication hole (211) and the second communication hole (211a).

9. The fuel cell stack according to any one of claims 1 to 4, wherein a first axis (CL1) extending in the specified direction through the center of the first communication hole (211) and a second axis (CL2) extending in the specified direction through the center of the second communication hole (211a) are located on the same straight line.

10. The fuel cell stack according to any one of claims 1 to 4, wherein the power generation cell (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 (23) and electrodes (24, 25) and a frame (21) supporting the membrane electrode assembly (20), and the pair of separators (3, 3) are arranged on both sides of the integrated electrode assembly (2) in the specified direction, the dummy cell (10) has a dummy assembly (11) and a pair of dummy separators (12, 12), the dummy assembly (11) has a dummy assembly (200) and a dummy frame (210) supporting the dummy assembly (200), and the pair of dummy separators (12, 12) are arranged on both sides of the dummy assembly (11) in the specified direction, the pair of separators (3, 3) and the pair of dummy separators (12, 12) are configured to be the same.

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