Vehicle fuel cell system

Abstract

To improve the assemblability of an on-vehicle fuel cell system.SOLUTION: There is provided an on-vehicle fuel cell system that is a fuel cell system including: a power generation structure in which a fuel cell stack and an auxiliary machine structure that includes an auxiliary machine sending and receiving gas with the fuel cell stack are connected to be integrated; and a power generation structure case accommodating the power generation structure. The fuel cell system includes: a pair of projections provided in either the power generation structure or the power generation structure case; and a pair of groove recesses provided in the other of the power generation structure or the power generation structure case to slidingly fit with the pair of projections, one of the pair of projections being a working fluid introduction member for supplying a working fluid to the power generation structure.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an on-board fuel cell system. [Background technology]

[0002] Patent Document 1 discloses a configuration in which a fuel cell stack is housed in a stack case and the stack case is fixed to a vehicle. In the above document, the stack case and the fuel cell stack are fastened together by fixing bolts from two perpendicular directions (specifically, the horizontal and vertical directions). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-040752 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration described in the above document, the fuel cell stack is housed in a stack case, the fuel cell stack is positioned, and then the fixing bolts are fastened from each direction, but for a heavy, large structure such as a fuel cell stack, the positioning work is difficult. In other words, the configuration described in the above document leaves room for improvement in terms of ease of assembly.

[0005] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to improve the assembly efficiency of an on-vehicle fuel cell system in which a fuel cell stack is housed in a case. [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 a fuel cell stack and an auxiliary structure including an auxiliary device for transferring gas between the fuel cell stack and the power generation structure are connected and integrated, and a power generation structure case for housing the power generation structure. The system comprises a pair of protrusions provided on either the power generation structure or the power generation structure case, and a pair of groove-like recesses provided on the other of the power generation structure or the power generation structure case and slidingly fitted with the protrusions, one of the pair of protrusions being a working fluid introduction member for supplying a working fluid to the power generation structure. Effect of the Invention

[0007] According to the above aspect, it is possible to improve the assembly efficiency of an on-vehicle fuel cell system in which a fuel cell stack is housed in a case. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is an exploded perspective view of an on-vehicle fuel cell system. [Diagram 2] FIG. 2 is a view of the on-board fuel cell system as seen from the left side in the left-right direction of the vehicle body. [Diagram 3] FIG. 3 is a perspective view of the front member of the power generation structure case as viewed obliquely from behind in the longitudinal direction of the vehicle body. [Figure 4] FIG. 4 is an enlarged view of the reinforcing portion. [Diagram 5] 5(A) and 5(B) are diagrams showing the movement of the second bracket relative to the reinforcing part in the assembly process. [Figure 6] FIG. 6 is an enlarged view of the joint between the second bracket and the power generation structure case. [Figure 7] FIG. 7 is an exploded perspective view of a power generating structure according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0010] 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 the fuel cell system 1 as seen from the left side in the left-right direction of the vehicle body. Fig. 3 is a perspective view of a front member 5, which will be described later, as seen diagonally from behind in the front-rear direction of the vehicle body.

[0011] The fuel cell system 1 of this embodiment is mounted on an electric vehicle that is driven by a drive motor. This embodiment assumes 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 prevent damage to the power generation structure A due to collision or interference with other parts, while reliably fixing it to the vehicle body. Second, since the fuel used is mainly flammable and odorless, it is necessary to suppress leakage from the fuel pipes, etc. to a level below the flammability limit. Note that an odorant is mixed into the fuel to make leakage easier to detect, but in order to suppress poisoning and deterioration of the catalyst caused by the odorant, the odorant is removed before being fed into the reformer. Third, the power generation temperature of the solid oxide fuel cell is high (500°C or higher), and this temperature must be maintained during system operation. On the other hand, other auxiliary equipment and on-board parts housed in the engine room are not resistant to such high temperatures. Therefore, insulation to suppress temperature drops due to heat radiation and heat shielding to protect other auxiliary equipment, etc. are required.

[0015] The power generation structure A has an auxiliary structure 3 disposed between the first fuel cell stack 2A and the second fuel cell stack 2B, and has a stacked structure in which the second fuel cell stack 2B, the auxiliary structure 3, and the first fuel cell stack 2A are stacked from the bottom up. The auxiliary structure 3 is a housing that contains the auxiliary devices (heat exchanger, combustor, etc.) that exchange gas with the first fuel cell stack 2A and the second fuel cell stack 2B. In the following description, the first fuel cell stack 2A and the second fuel cell stack 2B will be collectively referred to as the fuel cell stack 2 unless there is a particular need to distinguish between them.

[0016] The auxiliary structure 3 has a left side surface in the left-right direction of the vehicle body formed with an opening of a flow path 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 bracket 9A described later. The auxiliary structure 3 has a left side surface in the left-right direction of the vehicle body formed with an opening of a flow path 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 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 be supplied to the fuel cell stack without passing through the heat exchanger as an auxiliary. The startup air supply pipe is a pipe for supplying air to be supplied to the anode electrode at the start-up of the fuel cell system. 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 as an auxiliary at the start-up of the fuel cell system 1.

[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 in the longitudinal direction of the vehicle body, and a rear member 6 arranged at the rear side in the longitudinal direction of the vehicle body. 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 including a front surface 5A which is the leading end in the front-rear direction of the vehicle body when mounted on the vehicle, two side surfaces 5B extending rearward from both sides of the front surface 5A in the left-right direction of the vehicle body, and an upper surface 5C and a lower surface 5D extending rearward from both sides of the front surface 5A in the up-down direction of the vehicle body. The power generation structure A is fixed only to the side surface 5B of the front member 5 with bolts (not shown) via first brackets 10A, 10B provided on the first fuel cell stack 2A, second brackets 9A, 9B provided on the auxiliary structure 3, and third brackets 11A, 11B provided on the second fuel cell stack 2B. The third bracket 11B on the right side in the left-right direction of the vehicle body is not shown.

[0020] The second bracket 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 bracket 9A is provided with passages that respectively 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 to which the second brackets 9A, 9B are attached from the front side in the vehicle front-rear direction, the upper side in the vehicle vertical direction, and the lower side in the vehicle vertical direction. This reinforcing portion 14 protrudes toward the inside of the front member 5 from other portions of the side surface 5B. 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 that connects the power generating structure A and an electrical unit 7 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, and the like. The sealing surface 6A is reinforced to increase the surface rigidity compared to other surfaces. Various methods can be used for the reinforcement, such as making the plate thickness of the sealing surface 6A thicker than other portions, or attaching a reinforcing material on a frame surrounding the opening 8.

[0023] The opening 8 is open toward the rear in the vehicle front-rear direction, and is closed by attaching the electrical unit 7 to the seal portion 8A. The rear member 6 also includes an eave-shaped protrusion 7B extending toward the rear in the vehicle front-rear 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 surfaces. In other words, the connection portion between the front member 5 and the rear member 6 is flat. This flat surface is aligned along 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 backward with respect to the vertical direction of the vehicle body).

[0025] Comparing the front member 5 and the rear member 6, the volume of the front member 5 that accommodates the power generating structure A is larger than that of the rear member 6, and as shown in Figure 2, most of the power generating structure A is accommodated in the front member 5.

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

[0027] Fig. 4 is a view of region IV in Fig. 3 viewed from the inside of the front member 5. Fig. 5 is a view showing the movement of the second bracket 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 extending in the same direction with a predetermined distance therebetween, and a stopper portion 14B connecting the ends of the guide portions 14A on the vehicle body front side. The predetermined distance here is equal to or slightly larger than the vehicle body vertical dimension of the portion of the second bracket 9A facing the inner surface of the side surface 5B.

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

[0030] The reinforcing part 14 on the right side in the vehicle body left-right direction has the same structure as above, except that the predetermined distance between the two guide parts 14A is the same as or slightly larger than the vertical dimension of the part facing the inner surface of the side surface 5B of the second bracket 9B on the right side in the vehicle body left-right direction.

[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 as shown in FIG. 5(A), the second bracket 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 bracket 9B on the right side in the left-right direction of the vehicle body. The bolt 16 is for fixing the second bracket 9A to the auxiliary structure 3.

[0032] Then, as shown in FIG. 5B, the power generation structure A is slid forward (in the direction of the arrow in FIG. 5A) until the end of the second bracket 9A on the vehicle front side abuts against the stopper portion 14B (see region C in FIG. 5B). The size of the stopper portion 14B, the shape of the second bracket 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 bracket 9A are aligned with each other when the second bracket 9A abuts against the stopper portion 14B. This allows the power generation structure case B and the second bracket 9A to be bolted together by inserting the bolt 18 through the bolt hole 15 in the side surface 5B from the outside of the power generation structure case B when the second bracket 9A abuts against the stopper portion 14B (see FIG. 6). The same applies to the second bracket 9B.

[0033] As described above, by having the air manifold also function as the second bracket 9A, the number of parts can be reduced compared to having the air manifold and the fixing bracket as separate parts. Also, since the air manifold is connected to an air supply pipe from the outside and the fixing bracket is fixed to the case, making them separate parts increases the contact area of ​​the power generation structure A with the outside. The larger the contact area, the greater the amount of heat dissipated to the outside of the case via the power generation structure case B, etc., and the easier it becomes for the temperature of the power generation structure A to decrease.

[0034] In contrast, in the present embodiment, when the air manifold also serves as the fixing bracket (second bracket 9A), the contact area is reduced, thereby suppressing the amount of heat dissipated from the power generating structure A to the outside of the case. Also, compared to a configuration in which the air manifold and the fixing bracket are provided separately, it is possible to reduce costs, weight, and labor.

[0035] Next, modified examples of this embodiment will be described. Note that the following two modified examples also fall within the scope of the present invention, just like this embodiment.

[0036] [First Modification] FIG. 7 is an exploded perspective view of the power generating structure A of the first modified example.

[0037] In this modification, the first fuel cell stack 2A is covered with heat insulating members 20A-20E. Although omitted in FIG. 7, heat insulating members are also attached to each side surface of the second fuel cell stack 2B in the front-rear direction and left-right direction of the vehicle body, and to the lower surface in the vertical direction of the vehicle body. Furthermore, heat insulating members are also attached to the side surface of the auxiliary structure 3 in the front direction of the vehicle body, the side surface in the rear direction of the vehicle body, except for the connection portion with the exhaust pipe 13, and the side surfaces in the left-right direction of the vehicle body, except for the second brackets 9A, 9B. Note that when it is not necessary to distinguish between the heat insulating members 20A-20E and other heat insulating members, they will be referred to as heat insulating members 20.

[0038] In this modification, the first brackets 10A, 10B and the third brackets 11A, 11B are attached to a heat insulating member.

[0039] Then, the power generating structure A with the heat insulating member 20 attached thereto is housed in a power generating structure case B.

[0040] The heat insulating member is made by molding and solidifying powdered heat insulating material into a plate shape. By covering the power generating structure A with the heat insulating member 20 in this way, the heat insulating performance can be improved compared to the case where only the power generating structure case B is used. In other words, it is possible to suppress the temperature drop of the power generating structure A caused by wind while traveling and the like, and the heat radiation from the power generating structure A.

[0041] Attaching the heat insulating member 20 as described above increases the dimensions of the power generating structure A. In addition, it is difficult to ensure the strength and rigidity of the heat insulating member 20 formed by molding and solidifying powder.

[0042] However, since the reinforcing portion 14 functions as a guide and a positioning stopper as described above, in the process of housing the power generating structure A in the power generating structure case B, the power generating structure A will not tilt significantly relative to the power generating structure case B or slide excessively and collide with the power generating structure case B. Therefore, even if a heat insulating member 20 with low strength and rigidity is used, there is no risk of damage during the assembly process. Furthermore, since there is no risk of damage, the clearance between the power generating structure A and the power generating structure case B can be made small. As a result, the size of the power generating structure case B can be prevented from increasing due to the attachment of the heat insulating member 20.

[0043] In this modified example, all surfaces of the power generating structure A except for the side surfaces of the auxiliary structure 3 in the left and right direction of the vehicle body are covered with heat insulating materials, but this is not limited to this. For example, as long as at least the surface of the power generating structure A on the front side of the vehicle body or the side surfaces in the left and right direction of the vehicle body (excluding the portions of the second brackets 9A and 9B of the auxiliary structure 3) are covered, the above-mentioned effect of suppressing the temperature drop and heat dissipation can be obtained.

[0044] In addition, the power generating structure A may be housed in the power generating structure case B before being attached to the rear surface of the vehicle body.

[0045] [Second modified example] In the above embodiment and first modified example, a groove-like recess 19 is formed in the reinforcing portion 14 of the power generation structure case B, and the second brackets 9A, 9B attached to the power generation structure A serve as convex portions that slide into the groove-like recess 19. In contrast, in this modified example, the second brackets 9A, 9B are attached to the inside of the power generation structure case B so as to protrude, and the auxiliary structure 3 of the power generation structure A has a structure that includes a groove-like recess 19 that slides into the second brackets 9A, 9B.

[0046] In this case, similarly to the above embodiment, the groove-like recess 19 also includes two guide portions 14A along which the second brackets 9A and 9B slide, and a stopper portion 14B that positions the power generating structure A. The stopper portion 14B connects the ends of the two guide portions 14A on the rear side of the vehicle body.

[0047] 6, the second brackets 9A, 9B are fixed to the power generation structure case B by bolts 18. When the front member 5 of the power generation structure case B is formed by casting, the second brackets 9A, 9B may be formed as a single unit.

[0048] Then, the power generating structure A is slid until the stopper portions 14B come into contact with the second brackets 9A, 9B, and then the second brackets 9A, 9B are bolted to the power generating structure A. In this case, the length of a bolt corresponding to the bolt 16 in Fig. 6 is increased, a through hole for the bolt is provided in the power generating structure case B, and the bolt is inserted from the outside of the power generating structure case B to bolt the second brackets 9A, 9B to the power generating structure A.

[0049] In this way, even if the power generating structure A has a groove-shaped recess that functions as a guide and a positioning stopper, and the power generating structure case B has a convex portion that slides into the groove-shaped recess, the same effects can be obtained as in the above embodiment.

[0050] As described above, in this embodiment, a fuel cell system is provided that includes a power generation structure A in which a fuel cell stack 2 and an auxiliary structure 3 including an auxiliary that transfers gas between the fuel cell stack 2 are connected and integrated, and a power generation structure case B that houses the power generation structure A. In this system, a pair of second brackets (protruding parts) 9A, 9B are provided on either the power generation structure A or the power generation structure case B, and a pair of groove-shaped recesses 19 are provided on the other of the power generation structure A or the power generation structure case B and slide-fit with the second brackets 9A, 9B, and one of the second brackets 9A, 9B (the second bracket 9A in this embodiment) is a working fluid introduction member that supplies a working fluid to the power generation structure A. According to this embodiment, the groove-shaped recesses 19 function as guides for the second brackets 9A, 9B as protruding parts, so that the assembly of the fuel cell system 1 is improved. In addition, the working fluid introduction member also serves as the second bracket 9A, and thus, compared to when each of them is constituted by a separate member, the number of parts and the number of assembly steps can be reduced, the associated costs can be reduced, and the weight of the fuel cell system can be reduced. Also, compared to when the working fluid introducing member and the second bracket 9A are separate members, the contact area between the power generating structure A and the power generating structure case B can be reduced, thereby suppressing the amount of heat dissipation from the power generating structure A. Furthermore, the groove-shaped recess 19 functions as a guide for the second brackets 9A, 9B, so that collision between the power generating structure A and the power generating structure case B when inserting the power generating structure A can be avoided.

[0051] In this embodiment, a stopper portion 14B is provided at the end of the groove-shaped recess 19 opposite to the side where the second brackets 9A, 9B enter, which abuts against the second brackets 9A, 9B to position the power generating structure A relative to the power generating structure case B. This makes it easier to position the power generating structure A and reduces the number of assembly steps.

[0052] In this embodiment, the groove-like recess 19 is a portion surrounded by a U-shaped guide rail composed of two guide portions 14A extending in the same direction with a certain distance therebetween and a stopper portion 14B connecting the ends of the guide portions 14A. As a result, one guide rail fulfills both the guide function and the positioning function, which reduces the number of parts and reduces the cost, weight, and assembly man-hours.

[0053] In this embodiment, the working fluid introducing member is an air manifold that supplies air to the power generation structure A. The air manifold is bolted to the power generation structure A or to the power generation structure case B. The working fluid introducing member as a protrusion may be a fuel manifold that supplies fuel (hydrogen) to the power generation structure A, or may be an air manifold and a fuel manifold integrated together.

[0054] In this embodiment, the air manifold also serves as a second bracket (fixing bracket) 9A that fixes the power generating structure A to the power generating structure case B. This makes it possible to reduce the number of parts, cost, weight, and assembly man-hours compared to when the air manifold and the second bracket 9A are separate members.

[0055] In this embodiment, the power generating structure case B has a box shape with an opening on the surface facing the rear of the vehicle when mounted on the vehicle, and the power generating structure A is provided with a heat insulating member 20 at least on the surface facing the front of the vehicle or the surface facing the side of the vehicle when mounted on the vehicle. This improves the heat insulating performance of the power generating structure A against the outside, suppressing temperature drops of the power generating structure A due to wind while the vehicle is running and temperature drops due to heat radiation from the power generating structure A, making it easier to maintain the temperature of the power generating structure A.

[0056] In this embodiment, the heat insulating member 20 is a member made by molding and solidifying a powdered heat insulating material. This allows for greater freedom in the shape that can be taken compared to a plate material coated with a liquid heat insulating material, and therefore allows the power generating structure A to be covered more densely.

[0057] It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the technical ideas described in the claims. [Explanation of symbols]

[0058] REFERENCE SIGNS LIST 1 Vehicle-mounted fuel cell system, 2 Fuel cell stack, 3 Auxiliary structure, 4 Wiring, 5 Front member, 6 Rear member, 7 Electrical unit, 13 Exhaust pipe, 14 Reinforcement portion, 15 Bolt hole, 16 Bolt, 19 Groove-shaped recess, 20 Heat insulating member

Claims

1. a power generation structure in which a fuel cell stack and an auxiliary structure including an auxiliary device for transferring gas between the fuel cell stack and the power generation structure are connected and integrated; a power generating structure case that houses the power generating structure; In a fuel cell system comprising: a pair of protrusions provided on either the power generating structure or the power generating structure case; a pair of groove-shaped recesses provided on the other of the power generating structure or the power generating structure case, the pair of protrusions slidingly fitted into the pair of protrusions, 2. An on-vehicle fuel cell system, wherein one of the pair of protrusions is a working fluid introduction member for supplying a working fluid to the power generating structure.

2. 2. The fuel cell system for vehicle installation according to claim 1, An on-board fuel cell system, wherein a stopper portion is provided at the end of the groove-shaped recess opposite the side into which the protrusion enters, the stopper portion abutting against the protrusion to position the power generation structure relative to the power generation structure case.

3. 3. The fuel cell system for vehicle installation according to claim 2, An in-vehicle fuel cell system, wherein the groove-shaped recess is a portion surrounded by a U-shaped guide rail consisting of two guide portions extending in the same direction at a predetermined distance from each other and a stopper portion connecting the ends of the guide portions.

4. 4. The fuel cell system for vehicle installation according to claim 1, The working fluid introduction member is an air manifold that supplies air to the power generation structure.

5. 5. The fuel cell system for vehicle installation according to claim 4, An in-vehicle fuel cell system, wherein the air manifold is bolted to the power generation structure or to a power generation structure case.

6. 6. The fuel cell system for vehicle installation according to claim 4 or 5, An in-vehicle fuel cell system, wherein the air manifold also serves as a fixing bracket for fixing the power generation structure to the power generation structure case.

7. 7. The fuel cell system for vehicle installation according to claim 1, the power generation structure case has a box shape with an opening on a surface facing the rear of the vehicle body when mounted on the vehicle, The power generating structure is provided with a heat insulating member at least on a surface facing the front of the vehicle body or a surface facing a side of the vehicle body when the power generating structure is mounted on the vehicle.

8. 8. The fuel cell system for vehicle installation according to claim 7, The in-vehicle fuel cell system, wherein the heat insulating member is a member formed by molding and hardening a powder heat insulating material.

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