Fuel cell stack

Abstract

SOLUTION: A case of a fuel cell stack 12 includes an opening 41 provided in the case, a filter 42 permeable to a fuel gas, and a cover 48 attached to the outside of the filter 42. A vent 55 penetrating the inside and the outside of the cover 80 is formed. In front view of the filter 42, an exposed portion of the filter 42 is not located on the extension line of the vent 55. The cover 48 has, around the vent 55, a convex potion formed in a convex shape outward from the main surface of the cover 48.SELECTED DRAWING: Figure 3

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 access affordable, reliable, sustainable, and advanced energy, research and development on fuel cells that contribute to energy efficiency have been carried out. A fuel cell stack is formed by stacking a plurality of fuel cells.

[0003] When a fuel cell stack is mounted on a vehicle, for example, as described in Patent Document 1 below, the fuel cell stack is housed in a stack case. Since it is assumed that a small amount of fuel gas (hydrogen gas) leaks from the fuel cell stack, it has been proposed to provide a ventilation structure in the stack case. For example, in the stack case described in Patent Document 1 below, a protective cover (ventilation cover) is provided on the wall surface of the stack case to protect the filter material.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the conventional protective cover provided on the stack case, since the filter material is exposed at some angles, it is insufficient to protect the filter material from external factors such as high-pressure washing.

[0006] An object of the present invention is to solve the above-described problems.

Means for Solving the Problems

[0007] One aspect of the present invention is a fuel cell stack comprising a cell stack having a plurality of power generation cells, and a case housing at least one of the cell stack and fuel cell auxiliary equipment, wherein the case has an opening formed in the case, a filter attached to the opening and permeable to fuel gas, and a cover attached to the outside of the filter. The fuel cell stack is such that a ventilation hole is formed that penetrates the inside and outside of the cover, the exposed portion of the filter is not located on the extension of the ventilation hole when viewed from the front, and the cover has a convex portion formed outward relative to the main surface of the cover around the ventilation hole. [Effects of the Invention]

[0008] Because protrusions are provided around the ventilation holes, the effects of external factors such as high-pressure washing (e.g., water intrusion) can be suppressed. Therefore, the filter material can be protected from the effects of external factors while ensuring the ventilation path necessary for ventilation. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view of a fuel cell vehicle equipped with a fuel cell stack according to an embodiment of the present invention. [Figure 2] Figure 2 is an exploded perspective view of the ventilation structure. [Figure 3] Figure 3 is a cross-sectional view of the upper ventilation section. [Figure 4] Figure 4 is a partially enlarged cross-sectional view of the upper ventilation section. [Figure 5] Figure 5 is a front view of the cover. [Figure 6] Figure 6 illustrates the ventilation system in a fuel cell vehicle while it is in operation. [Figure 7] Figure 7 is a cross-sectional view of a modified ventilation structure. [Modes for carrying out the invention]

[0010] The fuel cell vehicle 10 shown in Figure 1 is equipped with a fuel cell stack 12 according to this embodiment. A front room 14 is provided at the front of the fuel cell vehicle 10. The front end of the fuel cell vehicle 10 has a front grille 16. While the fuel cell vehicle 10 is running, air enters the front room 14 as running air from the front grille 16, etc.

[0011] The fuel cell stack 12 comprises a cell stack 18, a stack case 20 housing the cell stack 18, and an auxiliary equipment case 22 housing fuel cell auxiliary equipment (not shown). The auxiliary equipment case 22 is adjacent to the stack case 20 in the vehicle width direction and is fixed to the stack case 20. The stack case 20 and the auxiliary equipment case 22 are housed in the front room 14. A motor and other equipment (not shown) are also arranged inside the front room 14. The motor is the source of driving force for the fuel cell vehicle 10.

[0012] The cell stack 18 has a plurality of power generation cells 19 stacked along the vehicle width direction. Although not shown in detail, each power generation cell has an electrolyte membrane-electrode structure (MEA) and a pair of separators that sandwich the electrolyte membrane-electrode structure from both sides. The electrolyte membrane-electrode structure comprises an electrolyte membrane, a cathode electrode, and an anode electrode. The cathode electrode and anode electrode are positioned on both sides of the electrolyte membrane. When a fuel gas (e.g., a hydrogen-containing gas such as hydrogen gas) is supplied to the anode electrode and an oxidizing gas (e.g., an oxygen-containing gas such as compressed air) is supplied to the cathode electrode, an electrochemical reaction between hydrogen and oxygen occurs, generating electricity.

[0013] At one end of the cell stack 18 in the stacking direction, a first terminal plate 24a, a first insulating plate 26a, and a first end plate 28a are sequentially arranged from the inside to the outside of the fuel cell stack 12. The first end plate 28a is part of the auxiliary case 22 and is fixed to the left end of the stack case 20 by bolts (not shown). At the other end of the cell stack 18 in the stacking direction, a second terminal plate 24b, a second insulating plate 26b, and a second end plate 28b are sequentially arranged from the inside to the outside of the fuel cell stack 12. The second end plate 28b is fixed to the right end of the stack case 20 by bolts (not shown).

[0014] The stack case 20 has an upper wall portion 30, a lower wall portion 32, and front and rear side wall portions 34 (front wall portion 34f and rear wall portion 34r) connecting the upper wall portion 30 and the lower wall portion 32. The opening at the left end of the stack case 20 is closed by a first end plate 28a, which is part of the auxiliary equipment case 22. The opening at the right end of the stack case 20 is closed by a second end plate 28b.

[0015] As shown in Figure 2, the stack case 20 has an opening 41 formed on the side of the stack case 20, a filter 42 attached to the opening 41 and permeable to fuel gas, and a cover 48 attached to the outside of the filter 42. Specifically, the stack case 20 further has a ventilation structure 38 located on the front wall portion 34f, which is one of the side walls 34. The ventilation structure 38 has an upper ventilation portion 38U located on the upper part of the front wall portion 34f and a lower ventilation portion 38L located on the lower part of the front wall portion 34f.

[0016] As shown in Figure 3, the upper ventilation section 38U has a ventilation hole structure 40 that penetrates the front wall section 34f, which is one of the side walls 34, and a filter 42 that is positioned on the outer surface of the front wall section 34f so as to cover the hole structure 40. The upper ventilation section 38U also has a support member 44 that supports the filter 42, a sealing member 46, and a cover 48 that covers the filter 42.

[0017] The rear surface 35 of the front wall portion 34f of the stack case 20 is spaced apart from the cell stack 18 of the fuel cell stack 12. Therefore, a gap G is formed between the front surface 18f of the cell stack 18 and the rear surface 35 of the front wall portion 34f. This gap G functions as a ventilation flow path.

[0018] As shown in FIG. 2, the hole structure 40 has a plurality of openings 41 penetrating the front wall portion 34f in the front-rear direction. In the hole structure 40, a plurality of openings 41 are arranged in the horizontal direction (vehicle width direction), and a plurality of openings 41 are arranged in the vertical direction. In the present embodiment, eight openings 41 are arranged in the horizontal direction, and two openings 41 are arranged in the vertical direction. The hole structure 40 has a total of 16 openings 41.

[0019] In the hole structure 40, a plurality of openings 41 are arranged so as to extend in the horizontal direction (vehicle width direction) as a whole. The outer surface 341 of the front wall portion 34f of the stack case 20 has a recess 50 extending in the horizontal direction (vehicle width direction). The recess 50 is a groove that depresses toward the inside of the stack case 20. The hole structure 40 opens at the bottom 51 of the recess 50. Note that the number of the openings 41 is not limited to the above number and can be arbitrarily set.

[0020] The filter 42 is, for example, a sheet-like member made of polytetrafluoroethylene (PTFE). As shown in FIG. 3, the filter 42 is disposed between the hole structure 40 and the cover 48. The filter 42 is housed in the recess 50. The filter 42 extends in the horizontal direction (vehicle width direction) and covers all the openings 41 of the hole structure 40.

[0021] The support member 44 supports the outer periphery of the filter 42. Specifically, the outer periphery of the front surface of the filter 42 is joined to the support member 44 by adhesive or the like. The support member 44 is an intermediate member positioned between the filter 42 and the cover 48. The support member 44 extends horizontally (in the vehicle width direction) and is housed in the recess 50. The support member 44 has a plurality of openings 45 for ventilation. The filter 42 is exposed forward through the plurality of openings 45. That is, the filter 42 has an exposed surface 42S (exposed portion) that is exposed toward the cover 48 and is not covered by the intermediate member, the support member 44.

[0022] A sealing member 46 is positioned between the outer periphery of the support member 44 and the front wall portion 34f, surrounding the hole structure 40. The sealing member 46 is made of an elastic material such as rubber. The bottom portion 51 of the recess 50 has an annular sealing groove 511 that surrounds the hole structure 40. The sealing member 46 is housed in the sealing groove 511. The outer periphery of the cover 48 presses against the support member 44, compressing the sealing member 46 between the support member 44 and the front wall portion 34f in the thickness direction of the front wall portion 34f.

[0023] A ventilation passage 54 is formed between the filter 42 and the cover 48. The filter 42 is exposed to the ventilation passage 54 through an opening 45 in the support member 44. The cover 48 has a ventilation hole 55 that connects the ventilation passage 54 to the outside of the stack case 20. Specifically, the cover 48 has a first ventilation hole 56 that connects the ventilation passage 54 to the outside of the stack case 20, and a second ventilation hole 58 that connects the ventilation passage 54 to the outside of the stack case 20. The second ventilation hole 58 is located below the first ventilation hole 56.

[0024] As shown in Figure 2, the cover 48 has a plurality (three in this embodiment) of first ventilation holes 56 and a plurality (three in this embodiment) of second ventilation holes 58. The plurality of first ventilation holes 56 are formed at intervals in the horizontal direction (vehicle width direction). The plurality of second ventilation holes 58 are formed at intervals in the horizontal direction (vehicle width direction). The first ventilation holes 56 and the second ventilation holes 58 are formed in a slit shape that extends in the horizontal direction (vehicle width direction).

[0025] As shown in Figure 3, the first ventilation hole 56 is located facing the upper part of the support member 44 in the horizontal direction (front-to-back direction). The first ventilation hole 56 is located facing the upper part of the ventilation passage 54. Therefore, the first ventilation hole 56 connects the upper part of the ventilation passage 54 to the outside of the stack case 20. The lower end surface 56L of the first ventilation hole 56 is located above the upper end surface 45U of the opening 45 of the support member 44. In a direction perpendicular to the surface 421 of the filter 42 (front view of the filter 42), the intermediate member, the support member 44, is located on the extension of the first ventilation hole 56, while the exposed surface 42S of the filter 42 is off the extension of the first ventilation hole 56.

[0026] The second ventilation hole 58 is located facing the lower part of the support member 44 in the horizontal direction (front-to-back direction). The second ventilation hole 58 is located facing the lower part of the ventilation passage 54. Therefore, the second ventilation hole 58 connects the lower part of the ventilation passage 54 to the outside of the stack case 20. The upper end surface 58U of the second ventilation hole 58 is located below the lower end surface 45L of the opening 45 of the support member 44. In a direction perpendicular to the surface 421 of the filter 42, the intermediate member, the support member 44, is located on the extension line of the second ventilation hole 58, and the exposed surface 42S of the filter 42 is off the extension line of the second ventilation hole 58. The height dimension of the rear opening 582 of the second ventilation hole 58 is smaller than the height dimension of the front opening 581 of the second ventilation hole 58. The rear opening 582 is located towards the top of the second ventilation hole 58. The second ventilation hole 58 and the lower part of the ventilation passage 54 form a crank-shaped labyrinth flow path 60.

[0027] In the vertical direction of the cover 48, no other ventilation holes are formed between the first ventilation hole 56 and the second ventilation hole 58. The cover 48 has an overlapping portion 48K that is positioned to overlap with the hole structure 40 when viewed from a direction perpendicular to the surface 421 of the filter 42.

[0028] The cover 48 has a cover body 62 facing the filter 42 and having a first ventilation hole 56 and a second ventilation hole 58 formed therein, and a pressing portion 64 that protrudes from the outer circumference of the cover body 62 toward the support member 44 and presses against the support member 44. The cover body 62 has a hole structure 40 and a surface 621 facing the filter 42. This surface 621 of the cover body 62 is located inside the recess 50. An overlapping portion 48K is provided on the cover body 62. The cover body 62 is spaced apart from the support member 44. A ventilation passage 54 is formed between the cover body 62 and the filter 42, and between the cover body 62 and the support member 44. The cover body 62 is housed in a recess 50 provided in the front wall portion 34f.

[0029] The cover 48 further has a plurality of fixing parts 68 that are fixed to the side wall 34 outside the recess 50. The plurality of fixing parts 68 are arranged at intervals in the circumferential direction (horizontal direction) on the outer circumference of the cover 48 (see also Figure 2). Each fixing part 68 is fastened to the front wall 34f by bolts 70. This fixes the cover 48 to the front wall 34f. Each fixing part 68 protrudes from the cover body 62 in the opposite direction (forward) to the direction in which the pressing part 64 protrudes from the cover body 62. Each fixing part 68 protrudes outward from the outer circumference of the cover 48.

[0030] As shown in Figure 5, with respect to their horizontal position, the first ventilation holes 56 and the second ventilation holes 58 are provided between horizontally adjacent fixing parts 68 among the multiple fixing parts 68.

[0031] The cover 48 further has protrusions 80. The cover 48 is provided with a plurality of protrusions 80 (three in this embodiment) corresponding to the plurality of first ventilation holes 56. The protrusions 80 are located above the first ventilation holes 56 and adjacent to the first ventilation holes 56. The protrusions 80 extend along the first ventilation holes 56. The horizontal length L2 of the protrusions 80 is greater than or equal to the horizontal length L1 of the first ventilation holes 56.

[0032] As shown in Figure 4, the protrusion 80 is located above and adjacent to the first ventilation hole 56, and protrudes more than the first ventilation hole 56 toward the outside (forward) of the stack case 20. The lower surface 801 of the protrusion 80 is at the same height as the upper end surface 56U of the first ventilation hole 56. The lower surface 801 of the protrusion 80 is a horizontal plane. The protrusion height H2 of the protrusion 80 from the cover body 62 is lower than the protrusion height H1 of the fixing portion 68 from the cover body 62.

[0033] The position of the tip 802 of the protrusion 80 is set such that the support member 44 lies on a straight line L passing through the tip 802 of the protrusion 80 and the upper end 623 of the surface 621 of the cover body 62. Therefore, when viewed from the outside of the cover 48, the upper part of the filter 42 is visually obscured by the cover 48 having the protrusion 80 or the support member 44. In other words, the filter 42 cannot be seen from the outside of the cover 48 through the first ventilation hole 56.

[0034] As shown in Figure 2, the lower ventilation section 38L has a ventilation hole structure 40L that penetrates the front wall section 34f, which is one of the side walls 34, a filter 42L positioned on the outer surface of the front wall section 34f so as to cover the hole structure 40L, and a support member 44L that supports the filter 42L. The lower ventilation section 38L further has a sealing member 46L positioned between the front wall section 34f and the support member 44, and a cover 48L that covers the filter 42L.

[0035] The hole structure 40L has a plurality of openings 41L that penetrate the front wall portion 34f in the front-rear direction. In the hole structure 40L, a plurality of openings 41L are arranged in the horizontal direction, and a plurality of openings 41L are arranged in the vertical direction. In this embodiment, three openings 41L are arranged in the horizontal direction, and two openings 41L are arranged in the vertical direction. The hole structure 40L has a total of six openings 41L.

[0036] The perforation structure 40L has multiple openings 41L arranged so as a whole it extends horizontally. The front wall portion 34f of the stack case 20 has a recess 50L that extends horizontally. The recess 50L is a groove that is recessed to the rear. The perforation structure 40L opens at the bottom of the recess 50L. Note that the number of openings 41L is not limited to the number described above and can be set arbitrarily.

[0037] The filter 42L, support member 44L, sealing member 46L, and cover 48L of the lower ventilation section 38L are basically the same as the filter 42, support member 44, sealing member 46, and cover 48 of the upper ventilation section 38U, but shorter in the horizontal direction (vehicle width direction). The filter 42L, support member 44L, sealing member 46L, and cover 48L have basically the same configuration as the filter 42, support member 44, sealing member 46, and cover 48, except for their horizontal length, so they are given the same reference numerals and detailed explanations are omitted. Accordingly, like the cover 48, the cover 48L also has a first ventilation hole 56, a second ventilation hole 58, and a protrusion 80. Since cover 48L is shorter than cover 48, the lengths and number of the first ventilation holes 56, the second ventilation holes 58, and the protrusions 80 in cover 48L differ from the lengths and number of the first ventilation holes 56, the second ventilation holes 58, and the protrusions 80 in cover 48.

[0038] The fuel cell stack 12 operates as follows:

[0039] In Figure 1, fuel gas, oxidizer gas, and cooling medium are supplied to the fuel cell stack 12. The fuel gas is supplied to the anode electrode of each power generation cell 19 via a fuel gas inlet communication hole (not shown). The oxidizer gas is supplied to the cathode electrode of each power generation cell 19 via an oxidizer gas inlet communication hole (not shown). Hydrogen in the fuel gas supplied to the anode electrode and oxygen in the oxidizer gas supplied to the cathode electrode are consumed by an electrochemical reaction within the electrode catalyst layer, generating electricity.

[0040] In the stack case 20, small amounts of fuel gas may leak from the cell stack 18. For this reason, a ventilation structure 38 is provided in the stack case 20. The ventilation structure 38 dilutes the fuel gas inside the stack case 20 by ventilating the inside of the stack case 20, thereby reducing the concentration of fuel gas. The ventilation structure 38 has an upper ventilation section 38U and a lower ventilation section 38L, and specifically, ventilation is performed by the upper ventilation section 38U and the lower ventilation section 38L. Below, we will describe the ventilation performed by the upper ventilation section 38U as a representative example, but ventilation is also performed by the lower ventilation section 38L based on the same principle.

[0041] As shown in Figure 3, the cover 48 of the ventilation structure 38 located in the stack case 20 has a first vent 56 that connects the ventilation passage 54 to the outside of the stack case 20, and a second vent 58 that connects the ventilation passage to the outside of the stack case 20. Due to the buoyancy of the fuel gas, the fuel gas is discharged from the space between the filter 42 and the cover 48 (ventilation passage 54) to the outside of the stack case 20 through the first vent 56. Pulled by the fuel gas discharged from the first vent 56, outside air is drawn into the space between the filter 42 and the cover 48 (ventilation passage 54) through the second vent 58.

[0042] As a result, natural ventilation occurs in the ventilation passage 54 inside the cover 48 due to the buoyancy of the fuel gas, and the concentration of the fuel gas in the space between the filter 42 and the cover 48 (ventilation passage 54) is diluted, creating a difference in fuel gas concentration between the inside and outside of the filter 42. In other words, the concentration of fuel gas in the space between the filter 42 and the cover 48 (ventilation passage 54) becomes lower than the concentration of fuel gas in the stack case 20, causing a flow of fuel gas from inside the stack case 20 into the space between the filter 42 and the cover 48 (ventilation passage 54). Therefore, the diffusion ventilation efficiency of the ventilation structure 38 can be improved.

[0043] The ventilation described above is natural ventilation utilizing the buoyancy of the fuel gas in the ventilation passage 54, and is mainly performed when the fuel cell vehicle 10 (see Figure 1) is stopped. On the other hand, while the fuel cell vehicle 10 is running, forced ventilation is performed using the airflow from the vehicle. Details of the forced ventilation will be described later.

[0044] The first ventilation opening 56 is located facing the upper part of the ventilation passage 54, and the second ventilation opening 58 is located facing the lower part of the ventilation passage 54, thereby enabling efficient discharge of fuel gas from the ventilation passage 54 and efficient intake of air into the ventilation passage 54.

[0045] In the vertical direction of the cover 48, no other ventilation holes are formed between the first ventilation hole 56 and the second ventilation hole 58. The cover 48 has an overlapping portion 48K positioned to overlap with the hole structure 40 when viewed from a direction perpendicular to the surface 421 of the filter 42. Therefore, the filter 42 can be well protected.

[0046] In the cover 48, the surface 621 facing the opening 41 is located inside the recess 50. Because the opening 41, the filter 42, and the surface (main surface) of the cover 48 are located inside the recess 50, when an impact (external load) is applied to the fuel cell vehicle 10 (see Figure 1), surrounding components are less likely to directly interfere with the ventilation structure 38.

[0047] As shown in Figure 3, the ventilation structure 38 has a support member 44 that supports the outer periphery of the filter 42, and the cover 48 presses the support member 44 toward the side wall 34. Because the support member 44 holds the filter 42 and the cover 48 presses the support member 44 toward the side wall 34, the filter 42 can be properly positioned relative to the hole structure 40, which is the ventilation opening.

[0048] The cover 48 has a cover body 62 in which a first ventilation hole 56 and a second ventilation hole 58 are formed, and a pressing portion 64 that protrudes from the outer circumference of the cover body 62 toward the support member 44 and presses against the support member 44. Because the pressing portion 64 presses against the support member 44, the support member 44 can be fixed well to the side wall portion 34. Because the pressing portion 64 protrudes from the outer circumference of the cover body 62, an appropriate ventilation passage 54 can be formed between the filter 42 and the cover body 62.

[0049] The fixing portion 68 of the cover 48 protrudes from the cover body 62 in the opposite direction to the protrusion direction of the pressing portion 64 from the cover body 62. The filter 42, support member 44, and cover body 62, which are parts with lower strength compared to other structural parts (low-strength structural parts), are housed in the recess 50. Therefore, for example, when an external load F from the front is applied to the ventilation structure 38, it is possible to avoid the external load F being directly input to the low-strength structural parts, thereby protecting the low-strength structural parts.

[0050] As shown in Figure 5, the multiple fixing parts 68 of the cover 48 are arranged at intervals in the horizontal direction. With respect to the horizontal position, the first ventilation hole 56 and the second ventilation hole 58 are provided between adjacent fixing parts 68 among the multiple fixing parts 68. When an external load F is applied to the cover 48, the external load F is transmitted to the fixing parts 68 (fastening parts) while avoiding the first ventilation hole 56 and the second ventilation hole 58, thereby suppressing damage to the cover 48.

[0051] As shown in Figure 3, a sealing member 46 is positioned between the support member 44 and the side wall portion 34. When the cover 48 presses against the support member 44, the sealing member 46 is compressed in the thickness direction of the side wall portion 34 between the support member 44 and the side wall portion 34. This configuration prevents water from entering the hole structure 40 from the outside of the stack case 20. The cover 48 not only protects the filter 42 but also has the function of compressing the sealing member 46, thus streamlining the structure.

[0052] The cover 48 has a protrusion 80 that is formed outward relative to the main surface of the cover 48 around the ventilation hole 55. The protrusion 80 projects outward from the stack case 20. Because the protrusion 80 is provided around the ventilation hole 55 (in this embodiment, adjacent to the upper part of the first ventilation hole 56), the influence of external factors such as high-pressure cleaning water W (e.g., water intrusion) can be suppressed. Therefore, the filter 42 can be protected from the influence of external factors while ensuring the ventilation path necessary for ventilation.

[0053] As shown in Figure 4, the lower surface 801 of the protrusion 80 is at the same height as the upper end surface 56U of the first ventilation hole 56, so the influence of external factors such as high-pressure cleaning water W can be suppressed more effectively.

[0054] The position of the tip 802 of the protrusion 80 is set such that the support member 44 lies on a straight line L passing through the tip 802 of the protrusion 80 and the end (upper end 623) of the surface 621 of the cover body 62. With this configuration, even if cleaning water enters the inside of the cover 48 (ventilation passage 54) through the first ventilation hole 56 during high-pressure cleaning, the cleaning water is prevented from directly hitting the filter 42, thus preventing damage to the filter 42.

[0055] As shown in Figure 5, the first ventilation hole 56 is formed in the shape of a slit extending horizontally, and the protrusion 80 extends along the first ventilation hole 56. Because the first ventilation hole 56 is formed in the shape of a slit, the cover 48 can effectively protect the filter 42 from foreign objects flying in from outside the stack case 20.

[0056] Since the horizontal length L2 of the protrusion 80 is greater than or equal to the horizontal length L1 of the first ventilation hole 56, the influence of external factors such as high-pressure cleaning water W can be suppressed more effectively.

[0057] As shown in Figure 3, the ventilation structure 38 includes a labyrinth flow path 60 formed by a second vent 58 and the lower part of the ventilation passage 54. The labyrinth flow path 60 also helps to suppress the influence of external factors such as high-pressure cleaning water W.

[0058] Furthermore, as shown by the dashed line in Figure 3, a protrusion 80L may be provided adjacent to the second ventilation hole 58. In this case, the protrusion 80L is located above and adjacent to the second ventilation hole 58, and protrudes more than the second ventilation hole 58 toward the outside (forward) of the stack case 20.

[0059] The filter 42 has an exposed surface 42S (exposed portion) that is exposed toward the cover 48 and is not covered by the intermediate member, the support member 44. In a direction perpendicular to the surface 421 of the filter 42, the support member 44 is located on the extension line of the first ventilation hole 56 and the second ventilation hole 58, and the exposed surface 42S of the filter 42 is off the extension line. With this configuration, even if foreign matter flying in from a direction perpendicular to the surface 421 of the filter 42 enters the ventilation passage 54 through the first ventilation hole 56 and the second ventilation hole 58, it is possible to prevent the foreign matter from directly hitting the exposed surface 42S of the filter 42.

[0060] While the fuel cell vehicle 10 shown in Figure 1 is in motion, forced ventilation is performed using the airflow from the vehicle as follows.

[0061] While the fuel cell vehicle 10 is in motion, air enters the front room 14 as airflow through the front grille 16, etc. The airflow that enters the front room 14 is blocked by auxiliary equipment (not shown) located in front of the stack case 20 within the front room 14, so it is difficult for the airflow to reach the top of the stack case 20. On the other hand, in the lower part of the front room 14, some of the airflow reaches the bottom of the stack case 20 without being blocked by auxiliary equipment such as the radiator or fan.

[0062] As shown in Figure 6, the airflow that reaches the bottom of the stack case 20 flows into the stack case 20 through the lower ventilation section 38L. Specifically, the airflow flows into the stack case 20 through the first ventilation holes 56 and the second ventilation holes 58 of the cover 48L, the ventilation passage 54L, the filter 42L, and the hole structure 40L (multiple openings 41L).

[0063] Thus, while the fuel cell vehicle 10 is in motion, the lower ventilation section 38L functions as an air inlet that takes in air (outside air) into the stack case 20. In the lower ventilation section 38L, the flow path from the first vent hole 56 and the second vent hole 58 to the filter 42L is bent. Therefore, even if foreign matter such as sand grains or dust is carried along by the airflow while driving, it is difficult for the foreign matter to reach the filter 42. Even if the foreign matter reaches the filter 42L, it is captured by the filter 42L.

[0064] Air flowing into the stack case 20 via the lower ventilation section 38L rises between the outer surface of the cell stack 18 and the inner surface of the stack case 20. If a small amount of fuel gas leaks from the fuel cell stack 12 into the stack case 20, the fuel gas also rises within the stack case 20. If a small amount of fuel gas leaks into the stack case 20, the fuel gas is carried by the air introduced into the stack case 20 by the airflow while driving and discharged to the outside of the stack case 20 via the upper ventilation section 38U.

[0065] Specifically, air flows out of the stack case 20 through the perforation structure 40 (multiple openings 41) of the upper ventilation section 38U, the filter 42, the ventilation passage 54, and the first ventilation holes 56 and second ventilation holes 58 of the cover 48 to the outside of the stack case 20. If fuel gas is leaking, the fuel gas diluted with air is discharged into the front room 14. In this way, while the fuel cell vehicle 10 is running, the upper ventilation section 38U functions as a discharge section that discharges air to the outside of the stack case 20.

[0066] The case in which the ventilation structure 38 is provided may also be the auxiliary equipment case 22. The ventilation structure 38 may be provided in both the stack case 20 and the auxiliary equipment case 22. The ventilation structure 38 may have only one of the upper ventilation section 38U and the lower ventilation section 38L. The ventilation structure 38 may have a ventilation section of the same structure as the upper ventilation section 38U or the lower ventilation section 38L at a height between the upper and lower parts of at least one of the stack case 20 and the auxiliary equipment case 22.

[0067] In the fuel cell stack 12 shown in Figure 1, the ventilation structure 38M, a modified example shown in Figure 7, may be used instead of the ventilation structure 38. In the upper ventilation section 38UM and lower ventilation section 38LM of the ventilation structure 38M, the protective covers 48M and 48LM do not have second ventilation holes. That is, the ventilation holes 55 provided in the protective covers 48M and 48LM consist only of the first ventilation holes 56. Even with this configuration, while the fuel cell vehicle 10 (see Figure 1) is running, the airflow flows into the stack case 20 via the lower ventilation section 38LM and is discharged outside the stack case 20 via the upper ventilation section 38UM. Therefore, forced ventilation by the airflow is possible.

[0068] The above embodiments can be summarized as follows:

[0069] The above embodiment discloses a fuel cell stack (12) comprising a cell stack (18) having a plurality of power generation cells (19), and a case housing at least one of the cell stack and fuel cell auxiliary equipment, wherein the case has openings (41, 41L) formed in the case, filters (42, 42L) attached to the openings and permeable to fuel gas, and covers (48, 48L) attached to the outside of the filters, with ventilation holes (55) formed that penetrate the inside and outside of the covers, the exposed portion of the filters not located on the extension of the ventilation holes in a front view of the filters, and the covers have protrusions (80, 80L) formed outwardly relative to the main surface of the covers around the ventilation holes.

[0070] The case has an upper wall portion (30), a lower wall portion (32), and a side wall portion (34) connecting the upper wall portion and the lower wall portion, and the opening is provided in the side wall portion.

[0071] A ventilation passage (54, 54L) is formed between the filter and the cover.

[0072] The lower surface (801) of the protrusion is at the same height as the upper end surface (56U) of the ventilation hole.

[0073] The ventilation holes are formed in the shape of slits extending in a predetermined direction, and the protrusions extend along the ventilation holes.

[0074] The length (L2) of the protrusion extending in a predetermined direction is equal to or greater than the length (L1) of the ventilation hole in a predetermined direction.

[0075] The fuel cell stack has a support member (44, 44L) that supports the outer periphery of the filter and has an opening for ventilation, at least a portion of which is positioned between the filter and the cover, the cover faces the filter and has the ventilation hole formed therein, the ventilation hole is provided in a position facing the support member, the cover has a surface (621) facing the filter, and the tip of the protrusion (802) is positioned such that the support member is located on a straight line (L) passing through the tip of the protrusion (802) and the edge of the surface of the cover.

[0076] The filter has support members (44, 44L) that support the filter, and in a front view of the filter, the support members are located on the extension of the ventilation holes.

[0077] A recess (50) is formed on the side of the case, which is recessed toward the inside of the case, and the opening is formed at the bottom (51) of the recess.

[0078] In the cover, the surface (621) facing the opening is located inside the recess.

[0079] The above embodiment discloses a fuel cell stack (12) comprising a cell stack (18) having a plurality of power generation cells (19), and a case housing at least one of the cell stack and fuel cell auxiliary equipment, wherein the case has openings (41, 41L) formed in the case, filters (42, 42L) attached to the openings and permeable to fuel gas, and covers (48, 48L) attached to the outside of the filters, with ventilation holes (55) formed that penetrate the inside and outside of the covers, and in a front view of the filters, the exposed portion of the filters is not located on the extension of the ventilation holes.

[0080] Furthermore, the present invention is not limited to the embodiments described above, and various configurations can be taken without departing from the spirit of the invention. [Explanation of Symbols]

[0081] 12…Fuel cell stack 18…Cell stack 20…Stackable cases 38…Ventilation structure 40, 40L…Porous structure 42, 42L…Filter 48, 48L... Cover 54, 54L... Ventilation passage 55...Ventilation hole 80, 80L...Protrusion

Claims

1. A cell stack having multiple power generation cells, A case for housing the aforementioned cell stack, A fuel cell stack comprising, The aforementioned case is, The opening formed in the case, A filter is attached to the aforementioned opening and is permeable to fuel gas, A cover attached to the outside of the aforementioned filter, A support member that supports the outer periphery of the filter and has an opening for ventilation, It has, The filter is held between the support member and the case. Ventilation holes are formed that penetrate the inside and outside of the cover. The portion of the support member that holds the filter between itself and the case is positioned between the filter and the ventilation hole in the thickness direction of the filter, so that, in a front view of the filter, the exposed portion of the filter is not located on the extension of the ventilation hole. The case has an upper wall portion, a lower wall portion, and a side wall portion connecting the upper wall portion and the lower wall portion. The aforementioned opening is provided in the side wall portion, The cover has a convex portion formed outward relative to the main surface of the cover, adjacent to the above-ground ventilation hole and along the ventilation hole.

2. In the fuel cell stack according to claim 1, A fuel cell stack in which a ventilation passage is formed between the filter and the cover.

3. A cell stack having a plurality of power generation cells, A case for housing the aforementioned cell stack, A fuel cell stack comprising, The aforementioned case is, The opening formed in the case, A filter is attached to the aforementioned opening and is permeable to fuel gas, A cover attached to the outside of the aforementioned filter, It has, Ventilation holes are formed that penetrate the inside and outside of the cover. In a front view of the filter, the exposed portion of the filter is not located on the extension of the ventilation hole. The cover has a protrusion formed outward relative to the main surface of the cover, adjacent to the ventilation hole and along the ventilation hole, The case has an upper wall portion, a lower wall portion, and a side wall portion connecting the upper wall portion and the lower wall portion. The aforementioned opening is provided in the side wall portion, A fuel cell stack wherein the protrusion projecting horizontally from the main surface of the cover has a horizontal lower surface facing downward in the vertical direction, and the lower surface is at the same height as the upper end surface of the ventilation hole.

4. In the fuel cell stack according to claim 3, The ventilation holes are formed in the shape of slits extending in a predetermined direction. Fuel cell stack.

5. In the fuel cell stack according to any one of claims 1 to 4, A fuel cell stack in which the length of the protrusion extending in a predetermined direction is greater than or equal to the length of the ventilation hole in a predetermined direction.

6. In the fuel cell stack according to claim 1 or 2, At least a portion of the support member is positioned between the filter and the cover. The cover faces the filter and has the ventilation holes formed therein. The ventilation holes are provided in a position facing the support member, The cover has a surface facing the filter, A fuel cell stack in which the tip of the protrusion is positioned such that the support member lies on a straight line passing through the tip of the protrusion and the edge of the surface of the cover.

7. In the fuel cell stack according to claim 1 or 2, A fuel cell stack in which, in a front view of the filter, the support member is located on the extension of the ventilation hole.

8. In the fuel cell stack according to any one of claims 1 to 7, The side surface of the side wall portion of the case has a recess formed in the inward direction of the case. The opening is located at the bottom of the recess, and the fuel cell stack is such that the opening is formed therein.

9. A cell stack having a plurality of power generation cells, A case for housing at least one of the cell stack and the fuel cell auxiliary equipment, A fuel cell stack comprising, The aforementioned case is, The opening formed in the case, A filter is attached to the aforementioned opening and is permeable to fuel gas, A cover attached to the outside of the aforementioned filter, It has, Ventilation holes are formed that penetrate the inside and outside of the cover. In a front view of the filter, the exposed portion of the filter is not located on the extension of the ventilation hole. The cover has a protrusion formed outward relative to the main surface of the cover, adjacent to the ventilation hole and along the ventilation hole, The case has an upper wall portion, a lower wall portion, and a side wall portion connecting the upper wall portion and the lower wall portion. The aforementioned opening is provided in the side wall portion, The side surface of the side wall portion of the case has a recess formed in the inward direction of the case. The aforementioned opening is located at the bottom of the recess, The surface of the cover facing the opening is the fuel cell stack located inside the recess.

10. A cell stack having multiple power generation cells, A case for housing the aforementioned cell stack, A fuel cell stack comprising, The aforementioned case is, The opening formed in the case, A filter is attached to the aforementioned opening and is permeable to fuel gas, A cover attached to the outside of the aforementioned filter, A support member that supports the outer periphery of the filter and has an opening for ventilation, It has, The filter is held between the support member and the case. Ventilation holes are formed that penetrate the inside and outside of the cover. A fuel cell stack in which the portion of the support member that holds the filter between itself and the case is located between the filter and the ventilation hole in the thickness direction of the filter, so that, in a front view of the filter, the exposed portion of the filter is not located on the extension of the ventilation hole.

11. A cell stack having a plurality of power generation cells, A case for housing the aforementioned cell stack, A fuel cell stack comprising, The aforementioned case is, The opening formed in the case, A filter is attached to the aforementioned opening and is permeable to fuel gas, A cover attached to the outside of the aforementioned filter, It has, Ventilation holes are formed that penetrate the inside and outside of the cover. In a front view of the filter, the exposed portion of the filter is not located on the extension of the ventilation hole. The cover has a protrusion formed outward relative to the main surface of the cover, adjacent to the ventilation hole and along the ventilation hole, The case has an upper wall portion, a lower wall portion, and a side wall portion connecting the upper wall portion and the lower wall portion. The aforementioned opening is provided in the side wall portion, The side surface of the side wall portion of the case has a recess formed in the inward direction of the case. The aforementioned protrusion is located inside the aforementioned recess and is part of the fuel cell stack.

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