fuel cell system

Abstract

To provide a fuel battery system capable of surely holding a fuel battery in a housing and suppressing wearing of a mount caused by input from the outside.SOLUTION: A fuel battery system comprises: a power generation structure in which at least one fuel battery stack configured by stacking unit cells and an accessory structure including an accessory exchanging a gas with the fuel battery stack are connected and integrated; and a power generation structure case in which the power generation structure is housed. In the fuel battery system, the accessory structure is fastened to the power generation structure case, and the fuel battery stack is fastened to the power generation structure case via a mount of which the end in a stacking direction is fastened to the accessory structure and the opposite side of the accessory structure can be displaced in the stacking direction.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Fuel cell systems are often used with the fuel cell stack housed in a housing to ensure waterproofing, etc. Patent Document 1 discloses a configuration in which the fuel cell is supported by the housing via multiple uniaxial mounts that can be displaced only in the direction of thermal expansion / contraction of the fuel cell, in order to prevent expansion stress from being applied to unexpected parts due to thermal expansion of the fuel cell housed in the housing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-043020 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration described in the above document, uniaxial mounts are used for all support parts. In other words, none of the support parts are fixed in the direction in which the uniaxial mount can be displaced. Therefore, when an external input is applied to the fuel cell system, micro-vibrations are generated in the direction in which the mount can be displaced, which may cause fretting wear on the uniaxial mount. For example, a fuel cell system mounted on a moving object such as a vehicle is subjected to inputs due to acceleration / deceleration and up / down vibrations of the moving object. Furthermore, even stationary fuel cell systems are subject to inputs due to earthquakes, and even portable fuel cell systems are subject to external inputs during transportation.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a fuel cell system that can securely hold a fuel cell within a housing and can suppress wear on the mount due to external inputs such as those described above. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a fuel cell system comprising: a power generation structure in which at least one fuel cell stack formed by stacking unit cells and an auxiliary structure including auxiliary machinery for exchanging gases with the fuel cell stack are connected and integrated; and a power generation structure case for housing the power generation structure. In this system, the auxiliary structure is fastened to the power generation structure case, and the fuel cell stack is fastened at one end in the stacking direction to the auxiliary structure and at the opposite end to the auxiliary structure to the power generation structure case via a mount that is displaceable in the stacking direction. The mount includes a cylindrical guide portion extending in the stacking direction and closed at both ends by lids, the cylindrical portion being fixed to the power generation structure case, a slider having a sliding portion slidably arranged inside the guide portion and a fixed portion fixed to the fuel cell stack, and a first elastic member arranged in the gap between the lid and the sliding portion that narrows when the fuel cell stack expands. [Effects of the Invention]

[0007] According to the above aspect, it is possible to provide a fuel cell system that can reliably hold the fuel cell within the housing and can suppress wear on the mount due to external input. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an exploded perspective view of an on-vehicle fuel cell system. [Figure 2] FIG. 2 is a view of the front member as seen from diagonally behind in the longitudinal direction of the vehicle body. [Figure 3] FIG. 3 is a view of region III in FIG. 2 as seen from the inside of the front member. [Figure 4] FIG. 4 is a diagram showing the movement of the second mount relative to the reinforcing part in the process of housing the power generating structure in the power generating structure case. [Figure 5] FIG. 5 is a view of the power generating structure supported by the front member as seen from the rear of the vehicle body. [Figure 6] FIG. 6 is a diagram in which the first fuel cell stack and the first mount are extracted from FIG. [Figure 7] FIG. 7 is an exploded perspective view of the first mount. [Figure 8] FIG. 8 is a cross-sectional view of the first mount. [Figure 9]FIG. 9 is a view showing the vicinity of the connection between the first mount and the fuel cell stack and the front member. [Figure 10] FIG. 10 is a diagram illustrating the first elastic member. [Figure 11] FIG. 11 is a diagram illustrating the second elastic member. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0010] [First embodiment] Fig. 1 is an exploded perspective view of an in-vehicle fuel cell system (hereinafter also referred to as "fuel cell system") 1 according to this embodiment. Fig. 2 is a view of a front member 5, which will be described later, seen obliquely from behind in the longitudinal direction of the vehicle body.

[0011] In this embodiment, a fuel cell system 1 mounted on an electric vehicle that runs on a drive motor will be described as an example. In addition, this embodiment is assumed to be a solid oxide fuel cell.

[0012] The fuel cell system 1 includes a power generating structure A and a power generating structure case B that houses the power generating structure A.

[0013] There are three main reasons why the power generating structure A is housed in the power generating structure case B.

[0014] First, this is to securely fix the power generation structure A to the vehicle body while preventing damage due to collisions or interference with other components. Second, because the fuel used is primarily flammable and odorless, leakage from the fuel cell stack and auxiliary structures must be kept below the flammability limit. Odorants are mixed into the fuel to make leak detection easier, but they are removed before being fed into the reformer to prevent catalyst poisoning and degradation. Third, solid oxide fuel cells generate electricity at high temperatures (over 500°C), and this temperature must be maintained during system operation. However, other auxiliary equipment and on-board components housed in the engine compartment cannot withstand such high temperatures. Therefore, insulation is required to prevent temperature drops due to heat dissipation, and heat shielding is required to protect other auxiliary equipment.

[0015] The power generation structure A has an auxiliary structure 3 disposed between a first fuel cell stack 2A and a second fuel cell stack 2B, and has a stacked structure in which the second fuel cell stack 2B, auxiliary structure 3, and first fuel cell stack 2A are stacked from bottom to top. The auxiliary structure 3 is a housing that contains auxiliary equipment (heat exchanger, combustor, etc.) that exchanges gas with the first fuel cell stack 2A and the second fuel cell stack 2B. In the following description, unless there is a need to particularly distinguish between them, the first fuel cell stack 2A and the second fuel cell stack 2B will be collectively referred to as the fuel cell stack 2. The fuel cell stack 2 is made up of unit cells stacked in the vertical direction of the vehicle body.

[0016] The auxiliary structure 3 has a left side surface in the left-right direction of the vehicle body formed with flow path openings to which an air supply pipe (not shown), a bypass air supply pipe (not shown), and a startup air supply pipe (not shown) are connected via a second mount 9A (described later). The auxiliary structure 3 also has a left side surface in the left-right direction of the vehicle body formed with flow path openings to which a fuel supply pipe (not shown) and a combustion fuel supply pipe (not shown) are connected. The air supply pipe is a pipe for supplying air from the outside to a heat exchanger serving as an auxiliary. The air supplied from the air supply pipe is heated by the heat exchanger and then supplied to the fuel cell stack 2. The bypass air supply pipe is a pipe for supplying air to the fuel cell stack without passing through the heat exchanger serving as an auxiliary. The startup air supply pipe is a pipe for supplying air to the anode electrode when the fuel cell system is started up. The fuel supply pipe is a pipe for supplying fuel gas to the fuel cell stack 2. The combustion fuel supply pipe is a pipe for supplying fuel gas to a combustor serving as an auxiliary when the fuel cell system 1 is started up.

[0017] Further, an opening 3A of an exhaust passage to which an exhaust pipe 13 is connected is provided on the rear side surface of the auxiliary structure 3 in the vehicle front-rear direction.

[0018] The power generation structure case B has a divided structure made up of a front member 5 arranged at the front side of the vehicle in the longitudinal direction, and a rear member 6 arranged at the rear side of the vehicle in the longitudinal direction. The front member 5 is formed, for example, by metal casting, and the rear member 6 is formed, for example, by pressing a steel plate.

[0019] The front member 5 has a box shape and includes a front surface 5A, which is the front end in the longitudinal direction of the vehicle when mounted on the vehicle, two side surfaces 5B extending rearward from both sides of the front surface 5A in the lateral direction of the vehicle, and an upper surface 5C and a lower surface 5D extending rearward from both sides of the front surface 5A in the vertical direction of the vehicle. The power generation structure A is fixed only to the side surface 5B of the front member 5 with bolts (not shown) via first mounts 10A and 10B provided on the first fuel cell stack 2A, second mounts 9A and 9B provided on the auxiliary structure 3, and third mounts 11A and 11B provided on the second fuel cell stack 2B. The structures of the first mounts 10A and 10B and the third mounts 11A and 11B will be described later. The third mount 11B on the right side in the lateral direction of the vehicle is not shown.

[0020] The second mount 9A on the left side in the left-right direction of the vehicle body also serves as a working fluid introduction member (more specifically, an air manifold) that supplies working fluid to the power generation structure A. The second mount 9A is provided with passages that connect the openings of the above-mentioned auxiliary structure 3 with an air supply pipe (not shown), a fuel supply pipe (not shown), a combustion fuel supply pipe (not shown), and a bypass air supply pipe (not shown).

[0021] The side surface 5B has a reinforcing portion 14 that surrounds the portion where the second mounts 9A and 9B are attached from the front side in the longitudinal direction of the vehicle body, the upper side in the vertical direction of the vehicle body, and the lower side in the vertical direction of the vehicle body. This reinforcing portion 14 protrudes from other portions of the side surface 5B toward the inside of the front member 5. The reinforcing portion 14 may be formed integrally with the front member 5, or may be formed as a separate member and attached to the front member 5.

[0022] The rear member 6 has a sealing surface 6A having an opening 8 through which passes wiring 4 connecting the power generating structure A and an electrical unit 7 located outside the power generating structure case B, and a sealing portion 8A surrounding the opening 8. The electrical unit 7 includes a controller, a converter, etc. The sealing surface 6A is reinforced to increase its surface rigidity compared to other surfaces. Various methods of reinforcement can be used, such as making the plate thickness of the sealing surface 6A thicker than other parts, or attaching a reinforcing material on a frame surrounding the opening 8.

[0023] The opening 8 is open toward the rear in the vehicle longitudinal direction, and is closed by attaching the electrical unit 7 to the seal portion 8A. The rear member 6 also has an eave-shaped protrusion 7B extending toward the rear in the vehicle longitudinal direction below the portion where the electrical unit 7 is attached.

[0024] The front member 5 and the rear member 6 are integrated by connecting a mating surface (front mating surface) 5E of the front member 5 and a mating surface (rear mating surface) 6C of the rear member 6. Both the front mating surface 5E and the rear mating surface 6C are flat. In other words, the connection portion between the front member 5 and the rear member 6 is flat. This flat surface is aligned with the left-right direction of the vehicle body, and the upper end is located rearward in the fore-and-aft direction of the vehicle body compared to the lower end (in other words, it is tilted rearward with respect to the up-and-down direction of the vehicle body).

[0025] Comparing the front member 5 and the rear member 6, the volume of the front member 5 that houses the power generating structure A is larger than that of the rear member 6, and most of the power generating structure A is housed in the front member 5.

[0026] Next, the reinforcing portion 14 will be described with reference to FIGS.

[0027] 2 from the inside of the front member 5. FIG. 4 is a diagram showing the movement of the second mount 9A relative to the reinforcing part 14 in the process of housing the power generating structure A in the power generating structure case B.

[0028] The reinforcing portion 14 includes two guide portions 14A that extend in the same direction with a predetermined distance between them, and a stopper portion 14B that connects the front ends of the guide portions 14A. The predetermined distance here is the same as or slightly larger than the vertical dimension of the portion of the second mount 9A that faces the inner surface of the side surface 5B.

[0029] The bolt holes 15 are holes through which bolts for fixing the second mount 9A to the power generation structure case B pass.

[0030] The reinforcing portion 14 on the right side in the vehicle transverse direction has the same structure as above, except that the predetermined distance between the two guide portions 14A is the same as or slightly larger than the vertical dimension of the portion of the second mount 9B on the right side in the vehicle transverse direction that faces the inner surface of the side surface 5B.

[0031] The reinforcing portion 14 functions as a guide and a positioning stopper in the process of housing the power generating structure A in the power generating structure case B. In this process, first, the position of the power generating structure A in the vertical direction of the vehicle body is adjusted, and then, as shown in FIG. 4A, the second mount 9A, which is a convex portion protruding in the left-right direction of the vehicle body from the power generating structure A, is fitted into a groove-like recess 19 formed by being surrounded by a U-shaped guide rail consisting of two guide portions 14A and a stopper portion 14B. At this time, the same is true for the second mount 9B on the right side in the left-right direction of the vehicle body. The bolt 16 is for fixing the second mount 9A to the auxiliary structure 3.

[0032] Then, as shown in FIG. 4B, the power generating structure A is slid forward in the vehicle body (in the direction of the arrow in FIG. 4A) until the end of the second mount 9A on the front side of the vehicle body abuts against the stopper portion 14B (see area C in FIG. 4B). The dimensions of the stopper portion 14B, the shape of the second mount 9A, and the position of the bolt hole 17 are set so that the bolt hole 15 in the side surface 5B and the bolt hole 17 in the second mount 9A are aligned with each other when the second mount 9A abuts against the stopper portion 14B. In this way, by inserting the bolt 18 into the bolt hole 15 in the side surface 5B from the outside of the power generating structure case B with the second mount 9A abutting against the stopper portion 14B, the power generating structure case B and the second mount 9A can be rigidly connected by the bolt.

[0033] The second mount 9B is basically the same as the second mount 9A, but the second mount 9B may have a fastening structure that allows for displacement in the left-right direction of the vehicle body rather than being rigidly connected, for example, by using a spacer or the like.

[0034] Next, the first mounts 10A, 10B and the third mounts 11A, 11B will be described. Fig. 5 is a view of the power generating structure A supported by the front member 5 as seen from the rear of the vehicle body.

[0035] As described above, the power generating structure A is supported on the front member 5 of the power generating structure case B via the first mounts 10A and 10B, the second mounts 9A and 9B, and the third mounts 11A and 11B. Of these support parts, the second mount 9A on the left side of the vehicle body is rigidly connected, while the second mount 9B on the right side of the vehicle body is fastened with a degree of freedom that allows it to move only in the left-right direction of the vehicle body. In contrast, the first mounts 10A and 10B and the third mounts 11A and 11B are structured to be movable in the stacking direction of the unit cells, that is, in the up-down direction of the vehicle body. The reason for this is as follows.

[0036] When the power generation structure A is housed in the power generation structure case B, it must be reliably supported to withstand external inputs. Meanwhile, the fuel cell stack 2, which is approximately the same temperature as the outside air when the vehicle is stopped, reaches a temperature of 500°C or higher when the vehicle is running. Because the temperature of the fuel cell stack 2 is higher when the vehicle is stopped than when it is running and because it has a large number of components, the stack length (the dimension in the vertical direction of the vehicle body) changes significantly between when the vehicle is running and when it is stopped. This change in stack length must therefore be accommodated. Therefore, the auxiliary structure 3 is reliably fixed to the power generation structure case B by the second mounts 9A and 9B, and the first mounts 10A and 10B and the third mounts 11A and 11B accommodate changes in the stack length of the fuel cell stack 2. Of course, the first mounts 10A, 10B and the third mounts 11A, 11B also function to reliably fix the power generation structure A in the longitudinal and lateral directions of the vehicle body.

[0037] Next, the structures of the first mounts 10A, 10B and the third mounts 11A, 11B will be described. Although there are differences in the way they are attached to the fuel cell stack 2, they share the same structure that allows for displacement in the vertical direction of the vehicle body, and therefore, in this embodiment, the first mount 10B will be described as an example.

[0038] FIG. 6 is a diagram in which the first fuel cell stack 2A and the first mounts 10A and 10B are extracted from FIG.

[0039] The first mounts 10A, 10B are fixed to the first fuel cell stack 2A via stays 20 of different shapes. The stays 20 are fixed to the upper end plate 21 of the first fuel cell stack 2A with bolts. The stays 20 may be formed integrally with the upper end plate 21.

[0040] 7 is an exploded perspective view of the first mount 10A. The first mount 10A includes a cylindrical portion 22 having a cylindrical guide portion 22A extending in the vertical direction of the vehicle body and fixed to the power generation structure case B, and a slider 23 having a sliding portion 23A slidably arranged inside the guide portion 22A and a fixed portion 23B fixed to the fuel cell stack 2. The ends of the guide portion 22A in the vertical direction of the vehicle body are closed by an upper cover 24A and a lower cover 24B. In the following description, unless otherwise specified, the cylindrical portion 22 includes the upper cover 24A and the lower cover 24B.

[0041] The first mount 10 also includes a third elastic member 26 that is disposed in the gap between the guide portion 22A and the sliding portion 23A and absorbs displacement of the sliding portion 23A in a direction perpendicular to the vertical direction of the vehicle body. Displacement in a direction perpendicular to the vertical direction of the vehicle body includes, for example, displacement due to input in the fore-and-aft direction of the vehicle body associated with acceleration and deceleration of the vehicle, and displacement due to input in the left-and-right direction of the vehicle body associated with turning of the vehicle. By disposing the third elastic member 26, even if there is displacement in a direction other than the vertical direction of the vehicle body, the displacement can be absorbed as long as it is within the stroke range of the third elastic member 26.

[0042] Furthermore, the first mount 10 includes fourth elastic members 25A and 25B that are disposed in the gaps between the upper cover 24A and the lower cover 24B and the sliding portion 23A to absorb displacement of the sliding portion 23A in the vertical direction of the vehicle body. Displacement in the vertical direction of the vehicle body includes displacement due to the expansion / contraction of the fuel cell stack 2 as described above, as well as displacement due to vertical vibrations caused by unevenness in the road surface while the vehicle is traveling. When there is no need to distinguish between the upper fourth elastic member 25A and the lower fourth elastic member 25B, they are collectively referred to as the fourth elastic member 25.

[0043] By providing these third elastic member 26 and fourth elastic member 25, it is possible to hold the slider 23 at a predetermined position inside the cylindrical portion 22, and to suppress rattle of the slider 23 inside the cylindrical portion 22.

[0044] The third elastic member 26 and the fourth elastic member 25 are made of two types of elastic bodies with different spring constants. In this embodiment, a wave spring made by bending a leaf spring (a plate-shaped spring material) into a wave shape is used as the elastic body.

[0045] The third elastic member 26 is formed by bending a wave spring along the shape of the guide portion 22A so as to fill the gap between the sliding portion 23A and the cylindrical portion 22 (excluding the upper cover 24A and the lower cover 24B), and the upper end wave spring 26A and the lower end wave spring 26C have the same spring constant. That is, the third elastic member 26 is configured such that one of the two types of wave springs (here, wave springs 26A and 26C) is split into two in the vertical direction of the vehicle body, and the split wave springs 26A and 26C sandwich the other of the two types of wave springs (here, wave spring 26B) from both sides in the vertical direction of the vehicle body.

[0046] It does not matter which of the wave springs 26A and 26C and the wave spring 26B has a larger spring constant. The same applies to the spring constant of the wave spring serving as the upper fourth elastic member 25A and the spring constant of the wave spring serving as the lower fourth elastic member 25B.

[0047] The vertical dimensions of each wave spring 26A-26C are arbitrary, but in this embodiment, the vertical dimension of the wave spring 26B that is not divided into two is equal to or greater than the sum of the vertical dimensions of each of the divided wave springs 26A and 26C.

[0048] The third elastic member 26 is not limited to a single wave spring bent into a shape that surrounds the sliding portion 23A as in the present embodiment. For example, independent wave springs may be disposed in the gaps in the left-right direction and the front-rear direction of the vehicle body.

[0049] By using a wave spring as the elastic body as described above, the gap between the cylindrical portion 22 and the sliding portion 23A can be made smaller than when a helical spring or the like is used, thereby allowing the first mount 10B to have a compact configuration. Furthermore, by using a wave spring, it can be brought into contact with both the sliding portion 23A and the cylindrical portion 22, making it easier to maintain the position of the sliding portion 23A within the cylindrical portion 22.

[0050] Furthermore, by using two types of wave springs with different spring constants, even if one wave spring resonates, the other wave spring can hold the slider 23. Furthermore, even if one wave spring loses its elastic force for some reason, the other wave spring can hold the slider 23. In particular, in this embodiment, the third elastic member 26 is configured so that the wave spring 26B, which has a relatively large dimension in the vertical direction of the vehicle body, is located in the center and the relatively small wave springs 26A and 26C are located on both ends thereof, thereby further improving the holding performance of the slider 23 when resonance or the like occurs in one of the wave springs.

[0051] Next, the third elastic member 26 will be described in more detail with reference to Figures 8 and 9. Figure 8 is a cross-sectional view of the first mount 10B taken along a plane perpendicular to the vertical direction of the vehicle body and passing through any part of the wave spring 26B in the vertical direction of the vehicle body. Figure 9 is a view showing the vicinity of the connection between the first mount 10B and the fuel cell stack 2 and the front member 5.

[0052] In this embodiment, for example, the wave spring is made of stainless steel, and the cylindrical portion 22 is made of a material (e.g., aluminum) with higher thermal conductivity than the wave spring. The slider 23 is made of a material (e.g., ceramic) with lower thermal conductivity than the portion of the fuel cell stack 2 to which the fixed portion 23B is fixed. In this embodiment, this portion of the fuel cell stack 2 becomes the stay 20, which is made of the same material as the end plate 21.

[0053] Furthermore, the wave spring 26B contacts both the sliding portion 23A and the guide portion 22A. If the contact portion between the wave spring 26B and the sliding portion 23A is designated as C1 (the cross-hatched portion in the figure) and the contact portion between the wave spring 26B and the guide portion 22A is designated as C2, the total contact area of ​​all contact portions C1 (15 locations in FIG. 8) is greater than the total contact area of ​​all contact portions C2 (12 locations in FIG. 8).

[0054] The same applies to wave spring 26C and wave spring 26A (not shown). The contact area between the wave spring constituting fourth elastic member 25 and upper lid 24A, lower lid 24B and the contact area between the wave spring and sliding portion 23A are also the same as above, and the contact area between the wave spring and upper lid 24A, lower lid 24B is larger than the contact area between the wave spring and sliding portion 23A.

[0055] The heat of the fuel cell stack 2 is transmitted to the slider 23 via the stay 20, from there to the tubular portion 22 via the wave spring 26 etc., transmitted to the front member 5 via the contact portion between the tubular portion 22 and the front member 5, and then released to the outside from the front member 5.

[0056] The fuel cell stack 2 reaches a high temperature during operation, and it is desirable to maintain a high temperature state in order to ensure a good electrolysis reaction. In other words, it is desirable to suppress heat radiation from the fuel cell stack 2 to the outside of the power generation structure case B. Furthermore, the wave springs (hereinafter referred to as "wave springs 26, etc.") that make up the third elastic member 26 and the fourth elastic members 25A, 25B may lose their elasticity due to high-temperature creep if their temperature rises excessively, so it is desirable to suppress temperature rises in the wave springs 26, etc.

[0057] In this regard, the slider 23 is made of a material with lower thermal conductivity than the stay 20, and therefore heat transfer from the fuel cell stack 2 to the slider 23 can be suppressed. That is, heat dissipation from the fuel cell stack 2 is suppressed, and the temperature rise of the wave spring 26 and the like due to heat transfer from the slider 23 is also suppressed.

[0058] Furthermore, since the cylindrical portion 22 is formed of a material with a higher thermal conductivity than the wave spring 26, etc., heat is more easily dissipated from the wave spring 26, etc. to the cylindrical portion 22. As described above, heat transfer from the slider 23 to the wave spring 26, etc. is suppressed, but heat transfer cannot be completely blocked. However, since heat is more easily dissipated from the wave spring 26, etc. to the cylindrical portion 22, a temperature rise in the wave spring 26, etc. can be suppressed. Furthermore, since the wave springs 26, etc. are each formed by bending a single plate, they have superior heat conductivity compared to a configuration made up of a combination of multiple components. This also contributes to suppressing a temperature rise in the wave spring 26, etc.

[0059] Furthermore, the wave spring 26 etc. has a shape in which the contact area with the cylindrical portion 22 is larger than the contact area with the slider 23, so that heat transfer from the slider 23 to the wave spring 26 etc. is suppressed and the heat transferred to the wave spring 26 etc. is easily released to the cylindrical portion 22.

[0060] In addition to the above-mentioned effects, by forming the wave spring 26 etc. by bending a single plate, the number of parts can be reduced, thereby reducing the number of assembly steps and costs.

[0061] Furthermore, if the wave spring 26 or the like is shaped so that the contact area with the cylindrical portion 22 is larger than the contact area with the slider 23, in addition to the above effects, it is possible to reduce the surface pressure at the contact area between the cylindrical portion 22 and the wave spring 26 or the like, thereby reducing wear on the cylindrical portion 22. It is also possible to reduce the sliding resistance between the slider 23 and the wave spring 26 or the like.

[0062] Next, the effects of this embodiment will be summarized.

[0063] The fuel cell system 1 of this embodiment includes a power generation structure A, which is an integrated structure of at least one fuel cell stack 2 formed by stacking unit cells, an auxiliary structure 3 including auxiliary components for exchanging gas with the fuel cell stack 2, and a power generation structure case B that houses the power generation structure A. The auxiliary structure 3 is fastened to the power generation structure case B, and the fuel cell stack 2 has one end in the stacking direction fastened to the auxiliary structure 3 and the other end opposite the auxiliary structure 3 fastened to the power generation structure case B via mounts 10A, 10B, 11A, and 11B that are displaceable in the stacking direction. Because the auxiliary structure 3 is fastened to the power generation structure case B, rattle of the power generation structure A is suppressed, thereby reducing wear and damage to the mounts. Furthermore, because the other end of the fuel cell stack 2 opposite the auxiliary structure 3 is fastened to the power generation structure case B via mounts 10A, 10B, 11A, and 11B that are displaceable in the stacking direction, displacement due to expansion / contraction of the fuel cell stack 2 can be absorbed.

[0064] In this embodiment, each mount 10A, 10B, 11A, and 11B includes a cylindrical portion 22 having a cylindrical guide portion 22A extending in the stacking direction and closed at both ends by lids 24A and 24B, and fixed to the power generation structure case B; and a slider 23 having a sliding portion 23A slidably disposed inside the guide portion 22A and a fixed portion 23B fixed to the fuel cell stack 2. The mounts 10A, 10B, 11A, and 11B further include a third elastic member 26 disposed in the gap between the guide portion 22A and the sliding portion 23A to absorb displacement of the sliding portion 23A in a direction perpendicular to the stacking direction. This allows for the third elastic member 26 to absorb displacement in a direction other than the stacking direction, for example, due to variations in temperature distribution within the fuel cell stack 2. Furthermore, since the sliding portion 23A can be held within the cylindrical portion 22 without play, fretting wear can be suppressed.

[0065] In this embodiment, the fuel cell system 1 further includes a fourth elastic member 25 that is disposed in the gap between the covers 24A, 24B and the sliding portion 23A and absorbs displacement of the sliding portion 23A in the stacking direction, and the third elastic member 26 and the fourth elastic member 25 are made of two types of elastic bodies with different spring constants. This allows the sliding element 23 to be held by one elastic body even if the other resonates. Also, even if the elasticity of one elastic body is lost, the other elastic body can still hold the sliding element 23.

[0066] In this embodiment, the third elastic member 26 and the fourth elastic member 25 are wave springs formed by bending a leaf spring into a wave shape. This allows the gap between the cylindrical portion 22 and the sliding portion 23A to be narrower than when a helical spring or the like is used, thereby enabling the first mount 10 and the third mount 11 to be made smaller and lighter. Furthermore, the position of the sliding element 23 can be kept constant even within the cylindrical portion 22.

[0067] In this embodiment, the third elastic member 26 and the fourth elastic member 25 have a shape in which the contact area with the guide portion 22A is larger than the contact area with the sliding portion 23A. This promotes heat dissipation from the third elastic member 26 and the fourth elastic member 25 to the cylindrical portion 22 and suppresses heat conduction from the sliding portion 23A, thereby suppressing deterioration of the third elastic member 26 and the fourth elastic member 25. Furthermore, the contact surface pressure with the cylindrical portion 22 can be reduced, thereby reducing wear on the cylindrical portion 22. Furthermore, the sliding resistance between the third elastic member 26 and the fourth elastic member 25 and the sliding portion 23A can be reduced, thereby smoothing the movement of the slider 23.

[0068] In this embodiment, each of the two types of elastic bodies that make up the third elastic member 26 is a single wave spring that has been processed into a shape that surrounds the sliding portion 23A. This improves heat transfer compared to a configuration made up of multiple components, and can suppress temperature increases in the third elastic member 26. Furthermore, fewer parts are required, which reduces costs.

[0069] In this embodiment, the third elastic member 26 has a configuration in which one of the two types of elastic bodies, elastic body 26A or 26C, is split in half in the stacking direction, and the split elastic body 26A or 26C sandwiches the other of the two types of elastic bodies, elastic body 26B, from both sides in the stacking direction. The dimension in the stacking direction of the unsplit elastic body 26B is equal to or greater than the sum of the dimensions in the stacking direction of the split elastic bodies 26A and 26C. That is, the elastic body 26B, which has a larger dimension in the stacking direction, supports the center portion of the sliding portion 23A, and the elastic bodies 26A and 26C, which have a smaller dimension in the stacking direction, support both sides of the center portion. This allows the slider 23 to be stably held even if one of the elastic bodies resonates or breaks.

[0070] In this embodiment, the cylindrical portion 22 is formed of a material having a higher thermal conductivity than the third elastic member 26 and the fourth elastic member 25. This makes it easier for heat transferred from the sliding portion 23A to the third elastic member 26 and the fourth elastic member 25 to escape to the cylindrical portion 22, thereby suppressing a rise in temperature of the third elastic member 26 and the fourth elastic member 25 and improving the reliability of the third elastic member 26 and the fourth elastic member 25.

[0071] In this embodiment, the slider 23 is made of a material having a lower thermal conductivity than the portion of the fuel cell stack 2 to which the fixed portion 23B is fixed (the stay 20 in this embodiment). This suppresses heat conduction from the fuel cell stack 2 to the slider 23, and in turn suppresses heat conduction from the slider 23 to the third elastic member 26 and the fourth elastic member 25. Furthermore, suppressing heat conduction from the fuel cell stack 2 to the slider 23 suppresses a decrease in the temperature of the fuel cell stack 2, thereby improving the efficiency of the fuel cell stack 2.

[0072] [Second embodiment] Next, a second embodiment will be described.

[0073] The fuel cell system 1 of this embodiment is provided with a first elastic member 27 and a second elastic member 28 in the gap between the tubular portion 22 and the sliding portion 23A in the vertical direction of the vehicle body, instead of or together with the fourth elastic member 25 described above.

[0074] The first elastic member 27 is disposed in the gap that narrows when the fuel cell stack 2 expands, that is, between the top cover 24A and the top surface of the sliding portion 23A.

[0075] 10, the free length X1 of the first elastic member 27 is equal to or greater than the distance Y1 between the top cover 24A and the top surface of the sliding part 23A when the fuel cell stack 2 is in the most contracted state. This prevents the first elastic member 27 from having play between the sliding part 23A and the top cover 24A.

[0076] The first elastic member 27 is made up of a portion 27A (hereinafter referred to as the first portion) with a first spring constant k1 and a portion 27B (hereinafter referred to as the second portion) with a second spring constant k2 that is greater than the first spring constant k1. The first portion 27A and the second portion 27B are both wave springs similar to those described in the first embodiment. The first elastic member 27 is made up of these wave springs stacked in the stacking direction so that the peaks of the first portion 27A and the valleys of the second portion 27B are in contact with each other, as shown in FIG. 10, for example.

[0077] The first spring constant k1 is a spring constant that can absorb the displacement of the sliding part 23A caused by the expansion / contraction of the fuel cell stack 2. The stroke of the first part 27A is equal to or greater than the displacement of the sliding part 23A caused by the expansion / contraction of the fuel cell stack 2.

[0078] The second spring constant k2 is a spring constant that can absorb displacement of the sliding part 23A due to an input in the vertical direction of the vehicle body (i.e., the stacking direction) even when the fuel cell stack 2 is in the most expanded state. In other words, the second spring constant k2 is a spring constant that can limit displacement of the sliding part 23A in the vertical direction of the vehicle body within an acceptable range when gravity acts in the vertical direction of the vehicle body when the fuel cell stack 2 is in the most expanded state.

[0079] The second elastic member 28 is disposed in the gap that narrows when the fuel cell stack 2 contracts, that is, between the lower cover 24B and the lower surface of the sliding portion 23A.

[0080] 11, the free length X2 of the second elastic member 28 is equal to or greater than the distance Y2 between the bottom cover 24B and the underside of the sliding part 23A when the fuel cell stack 2 is in the most expanded state. This prevents play between the second elastic member 28 and the sliding part 23A and the bottom cover 24B.

[0081] The second elastic member 28 is made up of a portion 28A (hereinafter referred to as the third portion) with a third spring constant k3 and a portion 28B (hereinafter referred to as the fourth portion) with a fourth spring constant k4, which is greater than the third spring constant k3. The third portion 28A and the fourth portion 28B are both wave springs similar to those described in the first embodiment. The second elastic member 28 is made up of these wave springs stacked in the stacking direction so that the valleys of the third portion 28A and the fourth portion 28B are in contact with each other, as shown in FIG. 11, for example.

[0082] The third spring constant k3 is a spring constant capable of absorbing the displacement of the sliding portion 23A caused by the contraction of the fuel cell stack 2. The stroke of the third portion 28A is equal to or greater than the displacement of the sliding portion 23A caused by the expansion / contraction of the fuel cell stack 2.

[0083] The fourth spring constant k4 is a spring constant that can absorb displacement of the sliding part 23A due to an input in the vertical direction of the vehicle body even when the fuel cell stack 2 is in the fully contracted state. In other words, the fourth spring constant k4 is a spring constant that can limit displacement of the sliding part 23A in the vertical direction of the vehicle body within an acceptable range when gravity acts in the vertical direction of the vehicle body when the fuel cell stack 2 is in the fully contracted state.

[0084] In this embodiment, the first spring constant k1 is equal to the third spring constant k3, and the second spring constant k2 is equal to the fourth spring constant k4. When the first elastic member 27 and the second elastic member 28 are used together with the fourth elastic member 25, for example, the first elastic member 27 may be sandwiched between two upper fourth elastic members 25A, and the second elastic member 28 may be sandwiched between two lower fourth elastic members 25B. In this case, the free length of the fourth elastic member 25 is set so that there is no slack in the fourth elastic member 25.

[0085] With the above configuration, the first part 27A and the third part 28A allow displacement due to expansion / contraction of the fuel cell stack 2, while pressing the fuel cell stack 2 in the opposite direction to the displacement, thereby securely holding the stack. Even if a large force is applied from outside the vehicle body, the second part 27B and the fourth part 28B can absorb the force and securely hold the fuel cell stack 2.

[0086] The first elastic member 27 and the second elastic member 28 are formed of the same material as the third elastic member 26 and the fourth elastic member 25. Also, a configuration may be provided that includes only either the first elastic member 27 or the second elastic member 28.

[0087] As described above, in this embodiment, each mount 10A, 10B, 11A, 11B includes a cylindrical portion 22 having a cylindrical guide portion 22A extending in the stacking direction and closed at both ends by lids 24A, 24B, which is fixed to the power generation structure case 3B, and a slider 23 having a sliding portion 23A slidably arranged inside the guide portion 22A and a fixed portion 23B fixed to the fuel cell stack 2. Furthermore, a first elastic member 27 is provided in the gap between the lids 24A, 24B and the sliding portion 23A, which narrows when the fuel cell stack 2 expands. This allows a compressive load to be applied to the fuel cell stack 2 while allowing for displacement due to expansion of the fuel cell stack 2, thereby enabling the fuel cell stack 2 to be securely held.

[0088] In this embodiment, the first elastic member 27 has a free length X1 equal to or greater than the distance Y1 between the top cover 24A and the sliding portion 23A when the fuel cell stack 2 is in the most contracted state. The first elastic member 27 has a first spring constant k1 that can absorb displacement of the sliding portion 23A due to expansion of the fuel cell stack 2, and a second spring constant k2 that is greater than the first spring constant k1 and can absorb displacement of the sliding portion 23A due to an input in the stacking direction even when the fuel cell stack 2 is in the most expanded state. This eliminates play in the first elastic member 27 between the top cover 24A and the sliding portion 23A, thereby suppressing fretting wear. Furthermore, the portion with the first spring constant k1 absorbs displacement due to expansion / contraction of the fuel cell stack 2, while the portion with the second spring constant k2 absorbs external input, thereby ensuring reliable support of the fuel cell stack 2.

[0089] In this embodiment, each mount 10A, 10B, 11A, 11B includes a second elastic member 28 that is disposed in the gap between the lid 24A, 24B and the sliding portion 23A that narrows when the fuel cell stack contracts. This allows a compressive load to be applied to the fuel cell stack 2 while allowing displacement due to contraction of the fuel cell stack 2, so that the fuel cell stack 2 can be securely held.

[0090] In this embodiment, the second elastic member 28 has a free length X2 equal to or greater than the distance Y2 between the bottom cover 24B and the sliding portion 23A when the fuel cell stack 2 is in the most expanded state. The second elastic member 28 has a third spring constant k3 that can absorb displacement of the sliding portion 23A due to contraction of the fuel cell stack 2, and a fourth spring constant k4 that is greater than the third spring constant k3 and can absorb displacement of the sliding portion 23A due to an input in the stacking direction even when the fuel cell stack 2 is in the most contracted state. This eliminates play in the second elastic member 28 between the bottom cover 24B and the sliding portion 23A, thereby suppressing fretting wear. Furthermore, the third spring constant k3 portion absorbs displacement due to expansion / contraction of the fuel cell stack 2, while the fourth spring constant k4 portion absorbs external input, thereby ensuring reliable support of the fuel cell stack 2.

[0091] In the above embodiments, the present invention has been described as being applied to an on-vehicle fuel cell system 1, but it can also be applied to a stationary or portable type.

[0092] Furthermore, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made within the scope of the technical idea set forth in the claims. [Explanation of symbols]

[0093] REFERENCE SIGNS LIST 1 Vehicle fuel cell system, 2 Fuel cell stack, 3 Auxiliary structure, 4 Wiring, 5 Front member, 6 Rear member, 7 Electrical unit, 10A, 10B First mount, 11A, 11B Third mount, 13 Exhaust pipe, 14 Reinforcement portion, 15 Bolt hole, 16 Bolt, 22 Cylinder portion, 23 Slider, 24 Lid, 25A, 25B Fourth elastic member, 26 Third elastic member, 27 First elastic member, 28 Second elastic member

Claims

1. a power generating structure in which at least one fuel cell stack formed by stacking unit cells and an auxiliary structure including auxiliary machinery for exchanging gases with the fuel cell stack are connected and integrated; a power generating structure case that houses the power generating structure; In a fuel cell system comprising: the auxiliary structure is fastened to the power generating structure case, one end of the fuel cell stack in the stacking direction is fastened to the auxiliary structure, and the other end opposite to the auxiliary structure is fastened to the power generation structure case via a mount that is displaceable in the stacking direction; The mount is a cylindrical portion having a cylindrical guide portion extending in the stacking direction and closed at both ends by a lid, the cylindrical portion being fixed to the power generating structure case; a slider having a sliding portion slidably disposed inside the guide portion and a fixed portion fixed to the fuel cell stack; a first elastic member disposed in a gap between the lid and the sliding portion that narrows when the fuel cell stack expands; A fuel cell system comprising:

2. In the fuel cell system according to claim 1, a fuel cell system, wherein the first elastic member comprises: a portion with a first spring constant whose free length is equal to or greater than the distance between the lid and the sliding portion when the fuel cell stack is in a fully contracted state and which can absorb displacement of the sliding portion due to expansion of the fuel cell stack; and a portion with a second spring constant greater than the first spring constant and which can absorb displacement of the sliding portion due to input in the stacking direction even when the fuel cell stack is in a fully expanded state.

3. 2. The fuel cell system according to claim 1, a second elastic member disposed in the gap between the lid and the sliding portion that narrows when the fuel cell stack contracts;

4. In the fuel cell system according to claim 3, a fuel cell system, wherein the second elastic member comprises: a portion with a third spring constant whose free length is equal to or greater than the distance between the lid and the sliding portion when the fuel cell stack is in a fully expanded state and which can absorb displacement of the sliding portion due to contraction of the fuel cell stack; and a portion with a fourth spring constant greater than the third spring constant and which can absorb displacement of the sliding portion due to input in the stacking direction even when the fuel cell stack is in a fully contracted state.

5. 2. The fuel cell system according to claim 1, a third elastic member disposed in a gap between the guide portion and the sliding portion, and absorbing displacement of the sliding portion in a direction perpendicular to the stacking direction;

6. In the fuel cell system according to claim 5, a fourth elastic member disposed in a gap between the lid and the sliding portion and configured to absorb displacement of the sliding portion in the stacking direction; A fuel cell system, wherein the third elastic member and the fourth elastic member are made of two types of elastic bodies having different spring constants.

7. In the fuel cell system according to claim 6, In a fuel cell system, the third elastic member and the fourth elastic member are wave springs formed by bending a leaf spring into a wave shape.

8. In the fuel cell system according to claim 7, a fuel cell system, wherein the third elastic member and the fourth elastic member have a shape such that the contact area with the guide portion is larger than the contact area with the sliding portion;

9. In the fuel cell system according to claim 7 or 8, A fuel cell system, wherein each of the two types of elastic bodies constituting the third elastic member is one of the wave springs processed into a shape that surrounds the sliding portion.

10. The fuel cell system according to claim 6, the third elastic member has a configuration in which one of the two types of elastic bodies is divided into two in the stacking direction, and the two divided elastic bodies sandwich the other of the two types of elastic bodies from both sides in the stacking direction, A fuel cell system, wherein the dimension in the stacking direction of the elastic body that is not divided into two is equal to or greater than the sum of the dimensions in the stacking direction of each of the divided elastic bodies.

11. In the fuel cell system according to claim 5, The cylindrical portion is formed of a material having a higher thermal conductivity than the third elastic member.

12. The fuel cell system according to claim 1, 3 or 5, A fuel cell system, wherein the slider is formed of a material having a lower thermal conductivity than a portion of the fuel cell stack to which the fixing portion is fixed.

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