JP7609607B2 - Fuel cell stack case - Google Patents

Description

The present invention relates to a fuel cell stack case that is installed in a fuel cell vehicle that uses hydrogen and oxygen as fuel.

In modern society, automobiles are an indispensable means of transportation, and various vehicles travel the roads in our daily lives. In recent years, fuel cells, which have a relatively small environmental impact, have been attracting attention as a new battery that can replace lead-acid batteries and lithium-ion batteries.

Such fuel cells are mounted on vehicles as fuel cell units. For example, as exemplified in Patent Document 1, a known fuel cell unit includes a fuel cell stack in which multiple unit cells are stacked while a compressive force is applied, and a fuel cell stack case that houses the fuel cell stack.

JP 2017-188376 A

Not only the above-mentioned patent documents but also current technologies cannot be said to adequately meet market needs, and the following problems exist.
That is, in the above-mentioned fuel cell unit, the fuel cell stack is sandwiched between a pair of end plates and fastened so that a desired pressure is applied via bolts, etc. Such end plates need to have strength and rigidity sufficient to apply the above-mentioned pressure, which makes them heavy.

On the other hand, the fuel cell stack case described above is essential for ensuring collision safety in fuel cells for vehicles, but if one tries to make it strong enough, the weight of the fuel cell stack case itself tends to increase. In this regard, for example, in the above-mentioned Patent Document 1, one of the pair of end plates is used as the case, which reduces the weight accordingly, but there is still a lot of room for improvement in order to achieve high fuel efficiency performance.

The present invention was made in consideration of the above-mentioned problems, and aims to provide a fuel cell stack case that can reduce the number of parts to reduce weight while still ensuring sufficient strength.

In order to solve the above problems, a fuel cell stack case in one embodiment of the present invention is a stack case for a fuel cell stack comprising: (1) a concave case body capable of accommodating a fuel cell stack; and a lid portion that closes the opening of the concave case body, wherein one of a pair of end plates that apply a predetermined pressure to the fuel cell stack constitutes the bottom of the concave case body, and the other of the pair of end plates constitutes the lid portion, and the lid portion is a concave body having a top plate and a peripheral wall that closes the opening of the concave case body, and a contact portion that seals the inside of the concave case body is formed by the side of the concave case body coming into contact with the side of the peripheral wall .

In addition, in the fuel cell stack case described in (1) above, (2) it is preferable that a predetermined gap is formed between the lid portion and the concave case body, and a first pressure adjustment member capable of adjusting the pressure is disposed in the gap, connecting the lid portion and the concave case body.

In addition, in the fuel cell stack case described in (1) or (2) above, (3) it is preferable that a second pressure adjustment member different from the first pressure adjustment member is provided between the lid portion and the concave case body.

Furthermore, in the fuel cell stack case described in any one of ( 1 ) to (3) above, ( 4 ) it is preferable that a side surface of the concave case body is provided with an annular protrusion portion protruding from the side surface and having an insertion hole into which the first pressure adjustment member is inserted, and that the case further has a restraining member that restrains a peripheral wall of the lid portion and the annular protrusion portion in the stacking direction.

The present invention makes it possible to reduce the number of parts in a fuel cell unit to be mounted on a vehicle, making it possible to reduce the weight while still ensuring sufficient strength.

FIG. 2 is a perspective view showing the appearance of a fuel cell stack case according to the embodiment. FIG. 2 is a perspective view showing the structure of a concave case body of a fuel cell stack case according to an embodiment. 2 is a perspective view showing the structure of a lid portion of a fuel cell stack case in an embodiment. FIG. 1 is a perspective view of a fuel cell stack case showing a state in which a predetermined pressure is applied by a pressure adjusting member of the present embodiment. FIG. 1A and 1B are a top view and an external side view, each showing a schematic cross section of a fuel cell stack case according to an embodiment; FIG. 11 is a perspective view showing the appearance of a fuel cell stack case in Modification 1. FIG. 11 is a perspective view showing the appearance of a fuel cell stack case in Modification 2.

Next, a preferred embodiment for carrying out the present invention will be described. In addition, configurations other than those described in detail below may be supplemented as appropriate with elemental technologies and configurations of known fuel cell units, including those in the patent documents mentioned above, and vehicles equipped with fuel cell units.

In the following description, the stacking direction of the single cells in the fuel cell unit housed in the fuel cell stack case is set as the Z direction, and the surface directions of the single cells are set as the X direction and the Y direction, respectively, for the sake of convenience. However, the definitions of these directions are merely examples and do not excessively limit the scope of the present invention.

<Fuel Cell Stack Case 100>
1 shows the external appearance of a fuel cell stack case 100 according to this embodiment. This fuel cell stack case 100 is mounted, for example, on a motor-driven vehicle that is equipped with a fuel cell unit. As an example, the fuel cell unit is configured to include at least the fuel cell stack case 100, which will be described in detail below, and a fuel cell stack CS.

The fuel cell stack CS includes multiple single cells that generate electricity through an electrochemical reaction between oxygen gas and hydrogen gas. These single cells are stacked along the Z-axis direction described above and fastened together under a predetermined pressure (compressive load) parallel to the stacking direction (Z direction).

Vehicles suitable for the present invention are not particularly limited as long as they are a structure capable of mounting a fuel cell unit, and examples thereof include four-wheeled automobiles, two-wheeled and three-wheeled automobiles, aircraft with wheels, and power storage devices such as stationary power sources for homes and offices.
The configuration of the fuel cell stack CS is not particularly limited as long as it is a stack configuration in which a plurality of unit cells are stacked, and any known fuel cell stack configuration, such as that described in Patent Document 1, can be used.

As can be seen from Figures 1 to 3, the fuel cell stack case 100 of this embodiment is configured to include a concave case body 10 and a lid portion 20. In this embodiment, as shown in Figure 1 and other figures, the fuel cell stack case 100 houses the fuel cell stack CS. Therefore, it is preferable that the fuel cell stack case 100 of this embodiment is a rectangular parallelepiped so as to match the outer shape of the fuel cell stack CS.

The main feature of this fuel cell stack case 100 is that one (EP1) of a pair of end plates EP1 and EP2 that apply a predetermined pressure to the fuel cell stack CS forms the bottom of the concave case body 10, and the other (EP2) of the pair of end plates forms the lid portion 20.

The concave case body 10 is a box-shaped member capable of housing the fuel cell stack CS described above. The material of the concave case body 10 can be, for example, aluminum or a composite of aluminum and synthetic resin. However, the material of the concave case body 10 is not limited to the above as long as it satisfies the specifications of the case, and other known materials such as titanium and CFRP can also be used.

As shown in FIG. 2 , the concave case body 10 in this embodiment includes a bottom plate 11 , a side plate 12 , and an annular protrusion 13 .
The bottom plate 11 is disposed opposite an end in the stacking direction of the fuel cell stack CS to be housed therein. As described above, the bottom plate 11 functions as a case for housing the fuel cell stack CS, and also functions as one of a pair of end plates for applying the predetermined pressure to the fuel cell stack CS.

In this embodiment, the shape of the bottom plate 11 in a plan view from the Z direction is hexagonal, but there is no particular limitation as long as the fuel cell stack CS can be accommodated in the accommodation area CA of the fuel cell stack CS; for example, the shape in the plan view may be rectangular.

The side panels 12 are side wall members erected in the Z direction from the periphery of the bottom panel 11 described above. In this embodiment, a total of five side panels 12 are erected from the periphery of the bottom panel 11, forming a storage area CA surrounded by the inner surfaces 12b of the side panels 12, and an insertion opening 10b is formed in the area where the side panels 12 are not erected from the bottom panel 11. As an example, the fuel cell stack CS may be accommodated in the storage area CA through the insertion opening 10b.

Also, as shown in the figure, an opening 10a is formed at the end of the concave case body 10 opposite the bottom plate 11, and the box-shaped fuel cell stack case 100 described above is realized by covering the end face 12c of the side plate 12 that forms this opening 10a with a lid portion 20, which will be described later.

In addition, in the concave case body 10 of this embodiment, an annular protrusion 13 is provided on the outer surface 12a of the side plate 12, which is closer to the opening end face described above. As can be seen from FIG. 1 and other figures, the annular protrusion 13 is formed so as to protrude from the outer surface 12a of the side plate 12 in the planar direction (the direction perpendicular to the Z direction).

The annular protrusion 13 is also formed with insertion holes (screw holes 13a to 13d) into which the first pressure adjustment member 30 described below is inserted. In this embodiment, the annular protrusion 13 is provided on some of the five side plates 12 described above, but it may be provided on all side plates 12, or may be installed only in areas where it is necessary to form the insertion holes described above. In this embodiment, the five side plates 12 are formed as a single unit, but this is not limited to this form, and each may be formed to stand independently from the bottom plate 11.

The lid portion 20 is a concave member configured to have the function of closing the opening 10a of the concave case body 10 described above. As shown in FIG. 3, the lid portion 20 in this embodiment is configured to include at least an upper plate 21 and a peripheral wall 22. The material of such a lid portion 20 can be the same material as the concave case body 10 described above, such as aluminum. Note that the lid portion 20 in this embodiment may be configured from a material different from that of the concave case body 10.

As can be seen from FIG. 5, when the lid 20 is attached to the concave case body 10, the side surface (outer surface 12a) of the concave case body 10 comes into contact with the side surface (inner surface 22b) of the peripheral wall 22, forming a contact portion Cp that seals the periphery of the concave case body 10. In the fuel cell stack case 100 of this embodiment, by providing this contact portion Cp, it is possible to, for example, improve the strength of the overlapping portion and have it function as a place to install a waterproof seal.

The top plate 21 is disposed opposite the stacking direction end of the fuel cell stack CS at the end opposite the bottom plate 11 in the stacking direction described above. In addition to functioning as a case for housing the fuel cell stack CS, the top plate 21 also functions as the other of a pair of end plates that apply the above-mentioned predetermined pressure to the fuel cell stack CS. In other words, referring also to FIG. 4, the bottom plate 11 and top plate 21 in this embodiment also function as a pair of end plates that apply a predetermined pressure to the fuel cell stack CS.

In this embodiment, the top plate 21 is hexagonal so that it has the same shape as the bottom plate 11 when viewed from the Z direction. However, this is not limited to this shape, and it may have the same shape as the bottom plate 11, or the shape when viewed from the plan view may be rectangular, etc., independent of the shape of the bottom plate 11.

As shown in Figures 1 and 3, the peripheral walls 22 are side wall members erected in the Z direction from the periphery of the above-mentioned upper plate 21. Such peripheral walls 22 are preferably molded integrally with the upper plate 21. In this embodiment, a total of five peripheral walls 22 are erected from the periphery of the upper plate 21 to correspond to the shape of the concave case body 10.

Therefore, when the lid 20 is attached to the concave case body 10, the area where the peripheral wall 22 is not erected from the top plate 21 is continuous with the insertion opening 10b described above. This makes it possible to temporarily remove the fuel cell stack CS from the accommodation area CA through the insertion opening 10b while the lid 20 is attached to the concave case body 10, for example, during maintenance.

As shown in FIG. 3, the lid 20 of this embodiment may further include an inner step 23. This inner step 23 is a portion that faces the end surface 12c of the side panel 12 of the concave case body 10 when the lid 20 is attached to the concave case body 10. The inner step 23 is not essential and may be omitted as appropriate.

In this embodiment, the inner step 23 can function as a seal point different from the contact point Cp described above. For example, if the fuel cell stack case of this embodiment further includes a cover member (not shown) that closes the insertion opening 10b, the end face 12c of the side panel 12 and the inner step 23 of the lid portion 20 come into close contact with each other, thereby improving the sealing performance.

As shown in Figures 4 and 5, when the lid 20 is attached to the concave case body 10, a predetermined gap GP is formed between the lid 20 and the concave case body 10. In this embodiment, a first pressure adjustment member 30 capable of adjusting the predetermined pressure is disposed in this gap GP to connect the lid 20 and the concave case body 10.

In this embodiment, the first pressure adjustment member 30 equipped with such pressure adjustment function is composed of four screw members 31 to 34. Of these, the set of screw members 31 and 32 and the set of screw members 33 and 34 are fastened to sandwich the fuel cell stack CS and connect the screw hole 13a of the annular protrusion 13 to the peripheral wall 22 of the lid portion 20. The first pressure adjustment member 30 adjusts the distance between the annular protrusion 13 and the peripheral wall 22, making it possible to adjust the strength of the above-mentioned specified pressure.

In this embodiment, a known screw is used as a specific example of the first pressure adjustment member 30, but the fastening method between the lid 20 and the concave case body 10 is not limited to the above. Specifically, for example, other known fastening means may be used, such as a bolt and nut structure without threading the screw hole 13a.

In this embodiment, the first pressure adjustment member 30 is capable of fastening the lid 20 and the concave case body 10 while generating the necessary pressure on the pair of end plates (the bottom plate 11 and the top plate 21).

The fuel cell stack case 100 of this embodiment may further include a second pressure adjustment member 40 that generates the necessary pressure on the pair of end plates (bottom plate 11 and top plate 21). As shown in FIG. 5, such a second pressure adjustment member 40 is a member different from the first pressure adjustment member 30, and can be provided between the lid portion 20 and the concave case body 10.

As an example, the second pressure adjustment member 40 in this embodiment can be a through bolt that is directly connected to a pair of end plates (bottom plate 11 and top plate 21). By further providing the fuel cell stack case 100 with such a second pressure adjustment member 40, it becomes possible to more accurately manage the value of the above-mentioned predetermined pressure (compression pressure) applied to the fuel cell stack CS.

As shown in the figure, the second pressure adjustment member 40 in this embodiment is composed of two through bolts 41 and 42, but it may be composed of one through bolt, or any number of through bolts (three or more) may be installed as long as the installation space allows.

As shown in FIG. 5, the fuel cell stack case 100 of this embodiment may be further configured to have a restraining member 50 as a stopper that restrains the peripheral wall 22 of the lid portion 20 and the annular protrusion portion 13 in the stacking direction. By providing this restraining member 50, even if the function of the first pressure adjustment member 30 is impaired by the impact of a collision as disclosed in Patent Document 1, for example, the case is prevented from being completely destroyed by expansion of the fuel cell stack CS in the stacking direction.

According to the present embodiment described above, in a fuel cell unit applied to a vehicle capable of running on a fuel cell, such as a fuel cell vehicle, the number of parts can be reduced, resulting in weight reduction, which can contribute greatly to fuel efficiency and other aspects. Furthermore, according to this embodiment, not only is weight reduction achieved, but it is also possible to ensure sufficient strength while applying the required pressure (compressive stress) to the fuel cell stack.

Although the preferred embodiment of the present invention has been described with reference to the attached drawings, the present invention is not limited to such an embodiment. In other words, it is obvious that a person skilled in the art can try to further modify the above-mentioned embodiment, and it is understood that such modifications are also within the technical scope of the present invention.
A modification of the above embodiment will now be described as an example.

<Modification 1>
FIG. 6 shows a fuel cell stack case 110 according to a first modified example of this embodiment.
As can be seen from the figure, the concave case body 10 of the present invention may be configured to include a frame portion 14 that is continuous in the circumferential direction (around θz in FIG. 6 ) and an opening (reduced insertion opening 10b) formed by this frame portion 14. By further providing such an opening in the fuel cell stack case 110, it becomes possible to access peripheral components (e.g., piping, bus bars, relays, cell voltage measuring devices, etc.) associated with the accommodated fuel cell via the opening.

That is, in the above-described embodiment, the insertion opening 10b is formed in an area where the side panel 12 is not erected from the bottom panel 11, but the main feature of this modified example 1 is that a part of this insertion opening 10b is blocked and becomes part of the frame portion 14. Furthermore, as shown in FIG. 6, the fuel cell stack case 110 of modified example 1 may be configured to have an annular protrusion portion 13 on the frame portion 14.

On the other hand, for the cover portion 20 as well, the peripheral wall 22 can be erected from the upper plate 21 so as to form a continuous annular wall in the circumferential direction as described above, in correspondence with the extended annular protrusion portion 13 and frame portion 14 .
As a result, by providing the fuel cell stack case 110 with the frame portion 14, it is possible to improve the rigidity of the concave case body 10.

In addition, by providing an annular protrusion 13 on the frame 14, it is possible to connect to the additional peripheral wall 22 of the lid 20 via the first pressure adjustment member 30. Furthermore, by providing an annular protrusion 13 on the frame 14, the number of locations where the above-mentioned waterproof seal can be installed increases, making it possible to improve sealing performance.

<Modification 2>
FIG. 7 shows a fuel cell stack case 120 according to a second modified example of this embodiment.
As shown in the figure, the fuel cell stack case 120 may be provided with an intermediate beam 15 that connects the inner surfaces 12b of the opposing side panels 12. This makes it possible to improve the rigidity of the concave case body 10.

Although one intermediate beam 15 is exemplified in this modified example 2, the present invention is not limited to this configuration, and for example, two or more intermediate beams 15 may be provided.
As shown in the figure, it is not always necessary to form the annular protrusion 13 on the frame 14, and the annular protrusion 13 can be omitted as appropriate. In this case, similar to the first modification, the frame 14 of this modification preferably has a strength sufficient to ensure the surface pressure necessary for installing the waterproof seal described above.

In the above-described embodiment, variant 1, and variant 2, the cover member covering the insertion opening 10b of the concave case body 10 is not shown, but the cover member covering the insertion opening 10b may be made of various known materials. In this case, if priority is given to internal airtightness, the cover member covering the insertion opening 10b may be made of the same structure as the other side surfaces (side panels 12), or if priority is given to further weight reduction, the cover member may be made thinner than the other side panels 12 or made of a different material, making it a simple specification.

In addition, in the above-mentioned embodiment and modified examples, a configuration in which the concave case body 10 fits inside the lid portion 20 is exemplified, but this is not limited to the configuration. For example, the outer shape of the lid portion 20 may be made smaller than the concave case body 10, and the lid portion 20 may be inserted inside the concave case body 10.

In the above embodiment, the restraining member 50 as a stopper is a member with a U-shaped cross section that is fitted to restrain the peripheral wall 22 and the annular protrusion 13 in the stacking direction, but this is not limited to the above embodiment. That is, as another example of the restraining member 50, for example, a structure in which through holes are formed in both the peripheral wall 22 and the annular protrusion 13 and a bolt is inserted into the through hole and fastened with a nut may be adopted, or a maximum separation distance between the peripheral wall 22 and the annular protrusion 13 may be set using a rivet.

Reference Signs List 100 Fuel cell stack case 10 Concave case body 11 Bottom plate 12 Side plate 13 Annular protrusion 20 Lid 21 Top plate 22 Peripheral wall 23 Inner step

Claims (4)

a concave case body capable of accommodating a fuel cell stack;
a lid portion that closes an opening of the concave case body,
one of a pair of end plates that apply a predetermined pressure to the fuel cell stack constitutes a bottom portion of the concave case body, and the other of the pair of end plates constitutes the lid portion;
the lid portion is a concave body having a top plate and a peripheral wall that close an opening of the concave case body,
a side surface of the concave case body and a side surface of the peripheral wall come into contact with each other to form a contact portion that seals the inside of the concave case body . A predetermined gap is formed between the lid portion and the concave case body,
2 . The fuel cell stack case according to claim 1 , wherein a first pressure adjusting member capable of adjusting the pressure is disposed in the gap, and connects the lid portion and the concave case body. The fuel cell stack case according to claim 1 or 2, wherein a second pressure adjustment member different from the first pressure adjustment member is provided between the lid portion and the concave case body. a ring-shaped protrusion portion protruding from a side surface of the concave case body and having an insertion hole into which the first pressure adjustment member is inserted;
4. The fuel cell stack case according to claim 1 , further comprising a restraining member that restrains the peripheral wall of the lid portion and the annular protrusion in the stacking direction.