Fuel Cell Systems

Abstract

Provided is a fuel cell system provided with a fuel cell unit that includes a fuel cell, an anode flow path, a cathode flow path, and a heat exchanger for heating a cathode gas supplied to the fuel cell. The fuel cell system is provided with a manifold that is attached to the fuel cell unit and distributes and supplies the cathode gas to the cathode flow path. The cathode flow path has a main flow path that passes through the heat exchanger, a bypass flow path that bypasses the heat exchanger to connect to the main flow path, and a partial reforming flow path for supplying a gas for partial oxidation reforming to the anode flow path. The manifold is configured as a gas distribution member provided with, in order from the upstream side: a first flow path connected to the main flow path; a second flow path provided adjacent to the first flow path and connected to the bypass flow path; and, a third flow path provided adjacent to the second flow path and connected to the partial reforming flow path. The manifold is also provided with a communication path that includes a first communication path for linking the first flow path and the second flow path, and a second communication path for linking the second flow path and the third flow path.

Description

[Technical field]

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

[0002] WO2018 / 051468A1 discloses a fuel cell system in which a cathode flow path through which cathode gas (air) flows has a path (main flow path) that passes through a heat exchanger, a path (bypass flow path) that bypasses the heat exchanger, and a path (POX flow path) that supplies air for partial reforming to the anode flow path. Summary of the Invention

[0003] When the cathode flow path of a fuel cell system has a bypass flow path, a POX flow path, or the like, pressure loss design is important to satisfy the required flow rate downstream of these flow paths. However, in WO2018 / 051468A1, the pressure loss design is not taken into consideration in the structure in which the cathode flow path is branched into a main flow path, a bypass flow path, and a POX flow path. For this reason, there is a risk that the pressure loss design of a flow path that requires a relatively high accuracy in gas flow rate control, such as a POX flow path, may become difficult.

[0004] In view of the above-mentioned problems, an object of the present invention is to provide a fuel cell system in which the pressure drop in the cathode flow passage can be easily designed.

[0005] According to one aspect of the present invention, there is provided a fuel cell system including a fuel cell unit including a fuel cell, an anode flow path that supplies an anode gas to the fuel cell, a cathode flow path that supplies a cathode gas to the fuel cell, and a heat exchanger that heats the cathode gas supplied to the fuel cell. The fuel cell system includes a manifold that is attached to the fuel cell unit and distributes and supplies the cathode gas to the cathode flow path. The cathode flow path has a main flow path that passes through the heat exchanger, a bypass flow path that bypasses the heat exchanger and connects to the main flow path, and a partial reforming flow path that supplies gas for partial oxidation reforming to the anode flow path. The manifold is configured as a gas distribution member that includes, in order from the upstream side, a first flow path that connects to the main flow path, a second flow path that is provided adjacent to the first flow path and connects to the bypass flow path, and a third flow path that is provided adjacent to the second flow path and connects to the partial reforming flow path. The manifold also includes a communication path including a first communication path that connects the first flow path to the second flow path, and a second communication path that connects the second flow path to the third flow path. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic configuration diagram of a fuel cell system according to a first embodiment. [Diagram 2] FIG. 2 is a schematic top view of the manifold. [Diagram 3] FIG. 3 is a perspective view of the manifold. [Figure 4] FIG. 4 is a diagram showing a manifold arranged so that the outlets of the first flow path, the second flow path, and the third flow path are on the lower side. [Diagram 5] FIG. 5 is a front view of the manifold removed from the fuel cell unit. [Figure 6] FIG. 6 is a view showing a state in which the first valve cylinder and the second valve cylinder are removed from the manifold. [Figure 7] FIG. 7 is a schematic top view of a manifold according to a modified example. [Figure 8] FIG. 8 is a top view of a manifold in a fuel cell system according to the second embodiment. [Figure 9]FIG. 9 is a schematic top view of a manifold according to a modified example of the second embodiment. [Figure 10] FIG. 10 is a top view of a manifold in a fuel cell system according to the third embodiment. [Figure 11] FIG. 11 is a schematic configuration diagram of a fuel cell system according to the fourth embodiment. [Figure 12] FIG. 12 is a schematic diagram showing the fuel cell unit with the bracket removed. [Figure 13] FIG. 13 is a schematic cross-sectional view of a vehicle equipped with a fuel cell system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0008] (First embodiment) 1 is a schematic diagram of a fuel cell system 100 according to a first embodiment. The fuel cell system 100 is a system mounted on, for example, a vehicle, and supplies a fuel gas (anode gas) and an oxidant gas (cathode gas) required for power generation to a fuel cell stack 1, causing the fuel cell stack 1 to generate power in response to an electric load such as an electric motor for driving the vehicle.

[0009] As shown in FIG. 1, the fuel cell system 100 comprises a fuel cell unit 10 consisting of two fuel cell stacks 1, an auxiliary structure 2 and a housing 3 for accommodating these, as well as a manifold 4 attached to the fuel cell unit 10.

[0010] The fuel cell stack (fuel cell) 1 is disposed on the upper and lower surfaces of the auxiliary structure 2. The fuel cell stack 1 is configured by stacking a plurality of fuel cells or fuel cell unit cells, and generates electricity by receiving anode gas and cathode gas. Each fuel cell, which is the power generation source of the fuel cell stack 1, is, for example, a solid oxide fuel cell (SOFC).

[0011] The auxiliary structure 2 is a substantially rectangular parallelepiped structure made of a mass of metal or the like, and is interposed between the two fuel cell stacks 1. The auxiliary structure 2 incorporates a gas flow path including an anode flow path that supplies an anode gas to the fuel cell stack 1 and a cathode flow path that supplies a cathode gas to the fuel cell stack 1, and a heat exchanger that heats the cathode gas supplied to the fuel cell stack 1. The gas flow path incorporated in the auxiliary structure 2 is connected to a gas supply path outside the auxiliary structure 2 via a side surface of the auxiliary structure 2, and is connected to the fuel cell stack 1 via an upper surface or a lower surface of the auxiliary structure 2. As a result, the anode gas and cathode gas from the outside of the auxiliary structure 2 pass through the gas flow path inside the auxiliary structure 2 and are supplied to the fuel cell stack 1. The auxiliary structure 2 may further incorporate an exhaust flow path, a combustor, etc., and the heat exchanger incorporated in the auxiliary structure 2 may be a heat exchanger integrated with the combustor.

[0012] The cathode flow path built into the auxiliary structure 2 has a main flow path 21 that passes through the heat exchanger, a bypass flow path 22 that bypasses the heat exchanger and connects to the main flow path 21, and a POX flow path (partial reforming flow path) 23 that connects to the anode flow path. The main flow path 21 is a flow path that supplies the cathode gas heated by the heat exchanger to the fuel cell stack 1. The bypass flow path 22 is a flow path for adjusting the temperature of the cathode gas supplied to the fuel cell stack 1 by supplying unheated air (hereinafter referred to as temperature adjustment gas) that has bypassed the heat exchanger to the main flow path 21. In addition, the POX flow path 23 is a flow path that supplies a gas for partial reforming (hereinafter referred to as reformed gas) to the anode flow path. One end of the main flow path 21, the bypass flow path 22, and the POX flow path 23 extends from the inside of the auxiliary structure 2 to the inner circumferential surface of the housing 3 that houses the fuel cell unit 10.

[0013] The housing 3 is made of metal or the like, and houses the fuel cell stack 1 and the auxiliary structure 2. A manifold 4 is fixed to the housing 3. The housing 3 also has a plurality of gas supply ports, each of which is connected to a gas flow path, such as a main flow path 21, a bypass flow path 22, and a POX flow path 23, built into the auxiliary structure 2. The fuel cell stack 1, the auxiliary structure 2, and the housing 3 constitute a fuel cell unit 10.

[0014] The manifold 4 is a member that distributes and supplies the cathode gas to the cathode flow passage in the auxiliary structure 2, and is attached to the housing 3 of the fuel cell unit 10. An inlet 44 of the manifold 4 is connected to a cathode gas supply source (not shown) such as a compressor. The manifold 4 includes, in order from the upstream side, a first flow passage 41 that connects to the main flow passage 21 of the cathode flow passage via a gas supply port of the housing 3, a second flow passage 42 that connects to the bypass flow passage 22, and a third flow passage 43 that connects to the POX flow passage 23. Note that a reinforcing material may be provided between the manifold 4 and the housing 3 to reinforce the connection portions between the first, second, and third flow passages 41, 42, and 43 of the manifold 4 and the cathode flow passage of the fuel cell unit 10. The manifold 4 will be described in detail later.

[0015] In the fuel cell system 100 configured as above, air (cathode gas) taken in by an air supply device such as a compressor is supplied to the cathode flow passage via the manifold 4.

[0016] Incidentally, when the cathode flow path of a fuel cell system has a bypass flow path, a POX flow path, etc., pressure loss design is important to satisfy the required flow rate downstream of these flow paths. Here, if the position and structure of the branching to the bypass flow path or the POX flow path are not appropriately set, there is a risk that the pressure loss design of the flow path will be difficult. For example, when the bypass flow path or the POX flow path after branching is long or when multiple branching points are provided, the pressure loss design elements increase and the design of the flow path becomes complicated. In addition, while it is necessary to flow a relatively high flow rate of gas in the bypass flow path, relatively high accuracy is required for the control of the POX flow rate, so it is required to supply a low flow rate of gas to the POX flow path. Therefore, if a flow path that requires relatively high control accuracy for the gas flow rate, such as the POX flow path, is directly branched from a flow path with a large flow rate, such as the main flow path, it may be difficult to adjust the gas flow rate, and the design of the flow path may become difficult.

[0017] In contrast, in this embodiment, the manifold 4 that distributes and supplies the cathode gas to the cathode flow path is attached to the fuel cell unit 10, and the manifold 4 is configured to have first, second, and third flow paths 41, 42, and 43 that are connected to the main flow path 21, the bypass flow path 22, and the POX flow path 23, respectively, from the upstream side. That is, the first and second flow paths 41 and 42 that connect to the main flow path 21 and the bypass flow path 22, which require a high flow rate, are provided on the upstream side, and the third flow path 43 that connects to the POX flow path 23, which requires a low flow rate, is provided on the most downstream side. As a result, the pressure loss of the cathode gas supplied from the manifold 4 to the POX flow path 23 is larger than the pressure loss of the cathode gas supplied to the main flow path 21 and the bypass flow path 22. In this way, the pressure loss of the cathode gas supplied to the main flow path 21 and the bypass flow path 22, which require a high flow rate, is small, and the pressure loss of the cathode gas supplied to the POX flow path 23, which requires a low flow rate, is large, making it easier to design the pressure loss in the cathode flow path. In addition, since the manifold 4 is used to distribute the cathode gas to the main flow path 21, the bypass flow path 22, and the POX flow path 23, the number of parts is reduced compared to the case where the cathode flow path has multiple branch points, resulting in lower costs, simplified assembly, fewer work processes, and a more compact system. In addition, since the manifold 4 is attached to the fuel cell unit 10, which includes the fuel cell stack 1, the heat exchanger, and gas flow paths such as the anode flow path and the cathode flow path, the manifold 4 can be closer to the fuel cell stack 1 and the gas flow paths. Therefore, the main flow path 21, the bypass flow path 22, and the POX flow path 23 can be shorter, making it easier to design the pressure loss of each flow path.

[0018] The manifold 4 will now be described in detail.

[0019] Fig. 2 is a schematic top view of the manifold 4, and Fig. 3 is a perspective view of the manifold 4. Both Fig. 2 and Fig. 3 are views of the fuel cell unit 10 with the manifold 4 removed.

[0020] As described above, the manifold 4 is a member that distributes and supplies cathode gas to the cathode flow passage of the fuel cell unit 10. As shown in Figures 2 and 3, the manifold 4 integrally includes, in order from the side closer to the inlet 44 (i.e., the upstream side), a first flow passage 41, a second flow passage 42 provided adjacent to the first flow passage 41, and a third flow passage 43 provided adjacent to the second flow passage 42. The first flow passage 41 is a flow passage that supplies the cathode gas to the main flow passage 21 of the cathode flow passage, the second flow passage 42 is a flow passage that supplies the cathode gas to the bypass flow passage 22, and the third flow passage 43 is a flow passage that supplies the cathode gas to the POX flow passage 23.

[0021] The manifold 4 also includes a communication passage 45 including a first communication passage 45a that connects the first flow passage 41 and the second flow passage 42, and a second communication passage 45b that connects the second flow passage 42 and the third flow passage 43. As shown in Fig. 2, the second communication passage 45b has a smaller flow passage cross-sectional area than the first communication passage 45a. The second communication passage 45b also has a longer passage length than the first communication passage 45a.

[0022] A first control valve 47 is provided on the second flow path 42 of the manifold 4 to adjust the amount of cathode gas distributed to the bypass flow path 22, and a second control valve 48 is provided on the third flow path 43 to adjust the amount of cathode gas distributed to the POX flow path 23.

[0023] The first control valve 47 is a stepping motor valve, and is composed of an electrically-driven first valve body 471, a hollow cylindrical first valve cylinder 472 fixed to the second flow path 42, and a first valve seat 473 provided at the tip of the first valve cylinder 472. The hollow part of the first valve cylinder 472 is a passage through which the cathode gas passes, and is connected to the bypass flow path 22. The opening degree of the first control valve 47 is adjusted by controlling the position of the first valve body 471 with a stepping motor, and thereby the flow rate of the cathode gas distributed to the bypass flow path 22 (bypass flow rate) is adjusted.

[0024] The second control valve 48 is a solenoid valve, and is composed of a second valve body 481 that opens and closes the third flow path 43, a hollow cylindrical second valve cylinder 482 fixed to the third flow path 43, and a second valve seat 483 provided at the tip of the second valve cylinder 482. The hollow part of the second valve cylinder 482 is a passage through which the cathode gas passes, and is connected to the POX flow path 23. The second control valve 48 is opened and closed by operating the second valve body 481 by electromagnetic force, thereby adjusting the flow rate of the cathode gas distributed to the POX flow path 23 (POX flow rate).

[0025] The flow rate of the cathode gas supplied from the first flow passage 41 to the main flow passage 21 can be adjusted by a compressor or the like of the cathode gas supply source.

[0026] In this way, the manifold 4 that distributes the cathode gas to the cathode flow paths and the control valve that adjusts the amount of cathode gas flowing into each flow path are integrated, so there is no need to provide a control valve as a separate component from the manifold 4, and the number of parts in the entire system can be reduced.

[0027] When the cathode gas is supplied from the compressor (air supply device) into the manifold 4 through the inlet 44, the cathode gas in the manifold 4 is distributed and supplied to the first flow path 41, the second flow path 42, and the third flow path 43. Specifically, a part of the cathode gas is directly supplied from the inlet 44 to the first flow path 41, a part is supplied from the inlet 44 to the second flow path 42 through the first communication passage 45a, and a part is supplied from the inlet 44 to the third flow path 43 through the first communication passage 45a, crosses the second flow path 42, and further passes through the second communication passage 45b. At this time, the pressure loss of the cathode gas from the inlet 44 to each flow path is smaller for the cathode gas supplied to the flow path on the upstream side. That is, the pressure loss of the cathode gas until it reaches each flow path of the manifold 4 is smallest in the first flow path 41 at the most upstream side connected to the main flow path 21, next smallest in the second flow path 42 connected to the bypass flow path 22, which is provided next to the first flow path 41, and largest in the third flow path 43 at the most downstream side connected to the POX flow path 23. As a result, the pressure loss of the cathode gas supplied to the main flow path 21 and the bypass flow path 22, which require a high flow rate, is small, and the pressure loss of the cathode gas supplied to the POX flow path 23, which requires a low flow rate, is large, making it easier to design the pressure loss in the cathode flow path.

[0028] Furthermore, among the communication passages 45, the second communication passage 45b on the downstream side has a smaller flow passage cross-sectional area than the first communication passage 45a on the upstream side, so the pressure loss of the cathode gas is larger in the second communication passage 45b than in the first communication passage 45a. Therefore, the pressure loss of the cathode gas supplied to the POX flow passage 23, which requires a low flow rate, becomes larger, making it easier to design the pressure loss in the cathode flow passage.

[0029] In addition, since the downstream second communication passage 45b is longer than the upstream first communication passage 45a, the difference in length also causes a larger pressure loss of the cathode gas in the second communication passage 45b than in the first communication passage 45a. Therefore, the pressure loss of the cathode gas supplied to the POX flow passage 23, which requires a low flow rate, becomes larger, making it easier to design the pressure loss in the cathode flow passage.

[0030] Furthermore, the flow of the cathode gas supplied to the third flow passage 43 through the first communication passage 45a and the second communication passage 45b is obstructed by the first control valve 47 provided on the second flow passage 42 when crossing the second flow passage 42. Therefore, the pressure loss of the cathode gas supplied from the third flow passage 43 to the POX flow passage 23 becomes even larger, making it even easier to design the pressure loss in the cathode flow passage.

[0031] The manifold 4 includes a flange 46 formed to surround the first flow path 41, the second flow path 42, and the third flow path 43. As shown in FIG. 3, a flange fixing portion 461 is formed on the periphery of the flange 46 to surround the first flow path 41, the second flow path 42, and the third flow path 43. The manifold 4 is fixed to the housing 3 such that the outlet 411 of the first flow path 41, the outlet 421 of the second flow path 42, and the outlet 431 of the third flow path 43 overlap with the gas supply ports of the housing 3 connected to the main flow path 21, the bypass flow path 22, and the POX flow path 23, respectively (FIGS. 1 and 2). The manifold 4 is fixed to the fuel cell unit 10 (housing 3) by bolts or the like at the flange fixing portion 461 formed to surround the first flow path 41, the second flow path 42, and the third flow path 43 (FIG. 1). In this way, the flange fixing portion 461 that fixes the manifold 4 to the fuel cell unit 10 is formed so as to surround the first flow path 41, the second flow path 42, and the third flow path 43, thereby improving the mounting rigidity and strength of the manifold 4 and making the mounting surface pressure uniform. This improves the sealing performance at the connection points between the flow paths 41, 42, 43 of the manifold 4 and the cathode flow path in the fuel cell unit 10.

[0032] Next, the first control valve 47 and the second control valve 48 will be described in detail.

[0033] As described above, the first control valve 47 is composed of an electrically operated first valve element 471, a first valve cylinder 472 fixed to the second flow path 42, and a first valve seat 473 provided at the tip of the first valve cylinder 472. In addition, the second control valve 48 is composed of a second valve element 481 that opens and closes the third flow path 43, a second valve cylinder 482 fixed to the third flow path 43, and a second valve seat 483 provided at the tip of the second valve cylinder 482.

[0034] As shown in FIG. 4, when the manifold 4 is installed so that the outlet 411 of the first flow passage 41, the outlet 421 of the second flow passage 42, and the outlet 431 of the third flow passage 43 are on the lower side, the first valve seat 473 is located above the bottoms of the first communication passage 45a and the second communication passage 45b. That is, the first valve seat 473 is located above the line X1 indicating the height of the bottom of the first communication passage 45a and the line X2 indicating the height of the bottom of the second communication passage 45b in FIG. 4. Similarly, when the manifold 4 is installed so that the outlet 411 of the first flow passage 41, the outlet 421 of the second flow passage 42, and the outlet 431 of the third flow passage 43 are on the lower side, the second valve seat 483 is located above the bottoms of the first communication passage 45a and the second communication passage 45b. That is, the second valve seat 483 is located above the line X1 and the line X2 of the second communication passage 45b in FIG. 4. As a result, even if condensed water accumulates in the communication passage 45, the first valve seat 473 and the second valve seat 483 are located above the bottoms of the first communication passage 45a and the second communication passage 45b, so that the first valve body 471 and the second valve body 481 are prevented from freezing and becoming stuck. In other words, since the first valve body 471 and the second valve body 481 are located above the first valve seat 473 and the second valve seat 483, respectively, the condensed water does not reach the first valve body 471 and the second valve body 481, and the first valve body 471 and the second valve body 481 are prevented from freezing and becoming stuck.

[0035] FIG. 5 is a front view of the manifold 4 removed from the fuel cell unit 10, as viewed from the directions of the outlets 411, 421, 431 of the first flow path 41, the second flow path 42 and the third flow path 43. FIG.

[0036] As shown in Fig. 5, a hollow cylindrical first valve cylinder 472 is fixed to the second flow passage 42, and a hollow cylindrical second valve cylinder 482 is fixed to the third flow passage 43. A cylindrical first housing 474 is provided on the outer periphery of the first valve cylinder 472, with the inner circumferential surface being in contact with the first valve cylinder 472. The first housing 474 surrounds the outer periphery of the first valve cylinder 472, and the outer circumferential surface of the first housing 474 is in contact with the inner circumferential surface of the second flow passage 42. Similarly, a cylindrical second housing 484 is provided on the outer periphery of the second valve cylinder 482, with the inner circumferential surface being in contact with the second valve cylinder 482. The second housing 484 surrounds the outer periphery of the second valve cylinder 482, and the outer circumferential surface of the second housing 484 is in contact with the inner circumferential surface of the third flow passage 43. By providing the housings 474, 484 in this manner, the outer peripheries of the first valve seat 473 and the second valve seat 483 located at the tips of the first valve cylinder 472 and the second valve cylinder 482 are closer to the centers of the second flow passage 42 and the third flow passage 43 by the thickness of the housings 474, 484. Therefore, when the manifold 4 is installed so that the flow directions of the first flow passage 41, the second flow passage 42, and the third flow passage 43 are horizontal to the ground, the lower parts of the first valve seat 473 and the second valve seat 483 are located higher by the thickness of the housings 474, 484 compared to when the housings 474, 484 are not present. For example, in Fig. 5, due to the presence of the first housing 474 and the second housing 484, the first valve seat 473 and the second valve seat 483 are located above the bottoms of the first communication passage 45a and the second communication passage 45b (in Fig. 5, the first valve cylinder 472 and the second valve cylinder 482 are located above the bottoms of the first communication passage 45a and the second communication passage 45b, but the first valve seat 473 and the second valve seat 483 and the first valve cylinder 472 and the second valve cylinder 482 are at the same height). That is, the first valve seat 473 and the second valve seat 483 are located above the straight line Y1 indicating the height of the bottom of the first communication passage 45a and the straight line Y2 indicating the height of the bottom of the second communication passage 45b in Fig. 5. In this way, since the first valve seat 473 and the second valve seat 483 are positioned above the first housing 474 and the second housing 484, even if condensed water accumulates in the connecting passage 45, the first valve body 471 and the second valve body 481 are prevented from freezing and becoming stuck.In other words, since the first valve body 471 and the second valve body 481 are provided at a position equal in height to the first valve seat 473 and the second valve seat 483, the condensation water remaining in the communicating passage 45 does not reach the first valve body 471 and the second valve body 481, thereby preventing the first valve body 471 and the second valve body 481 from freezing and becoming stuck.

[0037] Further, the first valve cylinder 472 of the first control valve 47 is configured to be detachable from the second flow passage 42, and the second valve cylinder 482 of the second control valve 48 is configured to be detachable from the third flow passage 43. FIG. 6 is a perspective view of the manifold 4 removed from the fuel cell unit 10, and shows the state in which the first valve cylinder 472 and the second valve cylinder 482 are removed from the manifold 4. The first valve cylinder 472 and the second valve cylinder 482 are fixed to the second flow passage 42 and the third flow passage 43, for example, by being screwed into the second flow passage 42 and the third flow passage 43, respectively. As described above, the first valve cylinder 472 and the second valve cylinder 482 are configured to have a hollow cylindrical shape, and the hollow portion is a passage through which the cathode gas passes. Therefore, by using the first valve cylinder 472 and the second valve cylinder 482 having hollow portions with different sizes, the adjustment range of the flow rate of the cathode gas supplied to the bypass flow passage 22 and the POX flow passage 23 can be changed. In this embodiment, since the first valve cylinder 472 and the second valve cylinder 482 are configured to be detachable from the second flow path 42 and the third flow path 43, the flow rate adjustment range can be changed by simply replacing the first valve cylinder 472 and the second valve cylinder 482 without replacing the entire manifold 4. Also, as shown in Fig. 6, the first valve cylinder 472 and the second valve cylinder 482 are inserted and attached into the second flow path 42 and the third flow path 43, respectively, from the same direction. In this way, since the first valve cylinder 472 and the second valve cylinder 482 are configured to be insertable into the second flow path 42 and the third flow path 43 from the same direction, workability during assembly is improved.

[0038] According to the fuel cell system 100 of the first embodiment described above, the following effects can be obtained.

[0039] The fuel cell system 100 includes a manifold 4 that is attached to the fuel cell unit 10 and distributes and supplies a cathode gas to the cathode flow path. The cathode flow path includes a main flow path 21 that passes through a heat exchanger, a bypass flow path 22 that bypasses the heat exchanger and connects to the main flow path 21, and a POX flow path (partial reforming flow path) 23 that supplies gas for partial oxidation reforming to the anode flow path. The manifold 4 is configured as a gas distribution member that includes, in order from the upstream side, a first flow path 41 that connects to the main flow path 21, a second flow path 42 that is provided next to the first flow path 41 and connects to the bypass flow path 22, and a third flow path 43 that is provided next to the second flow path 42 and connects to the POX flow path (partial reforming flow path) 23. In this way, the first and second flow paths 41 and 42 that connect to the main flow path 21 and bypass flow path 22, which require a high flow rate, are provided on the upstream side, and the third flow path 43 that connects to the POX flow path 23, which requires a low flow rate, is provided on the most downstream side. As a result, the pressure loss of the cathode gas supplied from the manifold 4 to the POX flow path (partial reforming flow path) 23 is greater than the pressure loss of the cathode gas supplied to the main flow path 21 and the bypass flow path 22. That is, the pressure loss of the cathode gas supplied to the main flow path 21 and the bypass flow path 22, which require a high flow rate, is small, while the pressure loss of the cathode gas supplied to the POX flow path (partial reforming flow path) 23, which requires a low flow rate, is large, making it easier to design the pressure loss in the cathode flow path.

[0040] In addition, since the cathode gas is distributed to the main flow path 21, the bypass flow path 22, and the POX flow path (partial reforming flow path) 23 by the manifold 4, the number of parts is reduced compared to the case where multiple branch points are provided in the cathode flow path. Therefore, it is possible to realize low costs, simplified assembly, fewer work processes, and a compact system.

[0041] Furthermore, since the manifold 4 is attached to the fuel cell unit 10, which includes the fuel cell stack 1, a heat exchanger, and gas flow paths such as the anode flow path and the cathode flow path, the manifold 4 can be located close to the fuel cell stack 1 and the gas flow paths. This allows the main flow path 21, the bypass flow path 22, and the POX flow path (partial reforming flow path) 23 to be shortened, making it easier to design the pressure drop of each flow path.

[0042] In the fuel cell system 100, the manifold 4 includes a communication passage 45 including a first communication passage 45a that connects the first flow passage 41 and the second flow passage 42, and a second communication passage 45b that connects the second flow passage 42 and the third flow passage 43, and the second communication passage 45b has a smaller flow passage cross-sectional area than the first communication passage 45a. As a result, the pressure loss of the cathode gas is larger in the downstream second communication passage 45b than in the upstream first communication passage 45a. For this reason, the pressure loss of the cathode gas supplied to the POX flow passage (partial reforming flow passage) 23, which requires a low flow rate, becomes larger, making it easier to design the pressure loss in the cathode flow passage.

[0043] In the fuel cell system 100, the second communication passage 45b of the manifold 4 is longer than the first communication passage 45a. As a result, the pressure loss of the cathode gas is greater in the downstream second communication passage 45b than in the upstream first communication passage 45a. This increases the pressure loss of the cathode gas supplied to the POX flow passage (partial reforming flow passage) 23, which requires a low flow rate, making it easier to design the pressure loss in the cathode flow passage.

[0044] The fuel cell system 100 includes a manifold 4 provided on the second flow path 42, a first control valve 47 for adjusting the amount of cathode gas (bypass flow rate) distributed to the bypass flow path 22, and a second control valve 48 provided on the third flow path 43 for adjusting the amount of cathode gas (POX flow rate) distributed to the POX flow path (partial reforming flow path) 23. In this way, the manifold 4 for distributing cathode gas to the cathode flow path and the control valve for adjusting the amount of cathode gas flowing in each flow path are integrated, so there is no need to provide a separate control valve, and the number of parts in the entire system can be reduced. Therefore, it is possible to achieve low costs, simplified assembly, reduced work processes, and a compact system.

[0045] Furthermore, since the first control valve 47 for adjusting the bypass flow rate is provided on the second flow path 42, the flow of the cathode gas supplied to the third flow path 43 through the first communication path 45a and the second communication path 45b is obstructed by the first control valve 47 when crossing the second flow path 42. Therefore, the pressure loss of the cathode gas supplied from the third flow path 43 to the POX flow path (partial reforming flow path) 23 becomes even larger, making it even easier to design the pressure loss in the cathode flow path.

[0046] In the fuel cell system 100, the manifold 4 includes a flange 46 formed to surround the first flow path 41, the second flow path 42, and the third flow path 43. The flange 46 has a flange fixing portion 461 for fixing the manifold 4 to the fuel cell unit 10, and the flange fixing portion 461 is formed to surround the first flow path 41, the second flow path 42, and the third flow path 43 of the manifold 4. Since the flange fixing portion 461 for fixing the manifold 4 to the fuel cell unit 10 is thus formed to surround the first flow path 41, the second flow path 42, and the third flow path 43, the mounting rigidity and mounting strength of the manifold 4 are improved and the mounting surface pressure is made uniform. This improves the sealing performance at the connection points between the flow paths 41, 42, and 43 of the manifold 4 and the cathode flow path in the fuel cell unit 10.

[0047] In the fuel cell system 100, the first control valve 47 is composed of a first valve body 471, a first valve cylinder 472 fixed to the second flow path 42, and a first valve seat 473 provided at the tip of the first valve cylinder 472. The second control valve 48 is composed of a second valve body 481, a second valve cylinder 482 fixed to the third flow path 43, and a second valve seat 483 provided at the tip of the second valve cylinder 482. When the manifold 4 is attached to the fuel cell unit 10 so that the outlet 421 of the second flow path 42 and the outlet 431 of the third flow path 43 are on the lower side, the first valve seat 473 and the second valve seat 483 are located above the first communication passage 45a and the second communication passage 45b. This prevents the first valve body 471 and the second valve body 481 from freezing and becoming stuck, even if condensed water accumulates in the communication passage 45.

[0048] The fuel cell system 100 includes a cylindrical first housing 474 surrounding the outer periphery of the first valve cylinder 472 and a cylindrical second housing 484 surrounding the outer periphery of the second valve cylinder 482. The first housing 474 has an inner circumferential surface in contact with the first valve cylinder 472 and an outer circumferential surface in contact with the inner circumferential surface of the second flow passage 42, and the second housing 484 has an inner circumferential surface in contact with the second valve cylinder 482 and an outer circumferential surface in contact with the inner circumferential surface of the third flow passage 43. As a result, when the manifold 4 is installed so that the flow directions of the first flow passage 41, the second flow passage 42, and the third flow passage 43 are horizontal to the ground, the lower parts of the first valve seat 473 and the second valve seat 483 are located higher by the thickness of the housings 474 and 484, respectively, compared to when the housings 474 and 484 are not present. Therefore, even if condensed water accumulates in the communication passage 45, the first valve body 471 and the second valve body 481 are prevented from freezing and becoming stuck.

[0049] In the fuel cell system 100, the first valve cylinder 472 is configured to be detachable from the second flow path 42, and the second valve cylinder 482 is configured to be detachable from the third flow path 43. This makes it possible to change the flow rate adjustment range by simply replacing the first valve cylinder 472 and the second valve cylinder 482, without replacing the entire manifold 4.

[0050] In the fuel cell system 100, the first valve body 471 and the second valve body 481 are attached to the second flow path 42 and the third flow path 43 by being inserted into the second flow path 42 and the third flow path 43, respectively, and the insertion directions of the first valve body 471 and the second valve body 481 are the same. In this way, the first valve cylinder 472 and the second valve cylinder 482 are configured to be insertable into the second flow path 42 and the third flow path 43 from the same direction, improving workability during assembly.

[0051] In the present embodiment, both the first communication passage 45a and the second communication passage 45b of the manifold 4 are formed in a linear cylindrical shape in Fig. 2, but the present invention is not limited thereto. For example, as shown in Fig. 7, the entire communication passage 45 may be formed in a tapered shape. Even with such a shape, the flow passage area of ​​the second communication passage 45b is smaller than that of the first communication passage 45a, so that the pressure loss of the cathode gas is larger in the downstream second communication passage 45b than in the upstream first communication passage 45a. Therefore, the pressure loss of the cathode gas supplied to the POX flow passage 23, which requires a low flow rate, becomes larger, and the pressure loss design in the cathode flow passage becomes easier.

[0052] 2 and 7, it is preferable to make the flow path cross-sectional area of ​​the downstream second communication passage 45b smaller than that of the upstream first communication passage 45a, but this is not necessarily limited to this, and for example, the flow path cross-sectional areas of the first communication passage 45a and the second communication passage 45b may be equal. Even in this case, if the third passage 43 connected to the POX passage 23 is provided downstream of the manifold 4, the pressure loss of the cathode gas supplied to the POX passage 23 will be large, making it easier to design the pressure loss in the cathode passage.

[0053] Similarly, as in this embodiment, it is preferable that the second communication passage 45b of the manifold 4 is longer than the first communication passage 45a, but this is not necessarily limited to this, and for example, the first communication passage 45a and the second communication passage 45b may be equal in length.

[0054] In addition, as in this embodiment, it is preferable that the manifold 4 that distributes the cathode gas to the cathode flow paths and the control valves that adjust the amount of cathode gas flowing in each flow path are integrated, but this is not necessarily limited to this. For example, the first control valve 47 and the second control valve 48 may be provided downstream of the manifold 4 as components separate from the manifold 4. Also, only one of the first control valve 47 that adjusts the bypass flow rate and the second control valve 48 that adjusts the POX flow rate may be provided in the manifold 4.

[0055] Furthermore, as in this embodiment, it is preferable to fix the manifold 4 to the fuel cell unit 10 by the flange fixing portion 461 of the flange 46, but the method of fixing the manifold 4 to the fuel cell unit 10 is not necessarily limited to this, and any known method may be used.

[0056] In addition, in this embodiment, the first control valve 47 is a stepping motor valve and the second control valve 48 is a solenoid valve, but this is not limited to this, and any known control device for adjusting the amount of cathode gas may be used.

[0057] Furthermore, as in this embodiment, it is preferable to provide the housings 474, 484 on the outer periphery of the valve cylinders 472, 482, but this is not necessarily limited to this, and a configuration in which the housings 474, 484 are not provided may also be used.

[0058] In addition, as in this embodiment, it is preferable to configure the valve cylinders 472, 482 to be attachable and detachable from the same direction, but this is not necessarily limited to this, and the valve cylinders 472, 482 may be configured so as not to be removable, and for example, the attachment and detachment directions of the first valve cylinder 472 and the second valve cylinder 482 may be different.

[0059] In addition, in this embodiment, the auxiliary structure 2 is interposed between the two fuel cell stacks 1, but the number of fuel cell stacks 1 and the positional relationship between the fuel cell stacks 1 and the auxiliary structure 2 are not necessarily limited to this and can be set arbitrarily.

[0060] Second embodiment A fuel cell system 100 according to a second embodiment will be described with reference to Fig. 8. Elements similar to those in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted.

[0061] 8 is a top view of the manifold 4 in the fuel cell system 100 according to the second embodiment. In this embodiment, the position of the communication passage 45 of the manifold 4 is different from that of the first embodiment.

[0062] As shown in FIG. 8, in the present embodiment as well, in the communication passage 45 of the manifold 4, the flow path area of ​​the second communication passage 45b is smaller than that of the first communication passage 45a, and the second communication passage 45b has a longer passage length than that of the first communication passage 45a.

[0063] On the other hand, unlike the first embodiment, the first communication passage 45a and the second communication passage 45b are configured so that the central axis L in the flow direction of the cathode gas is aligned in the same straight line. As a result, when machining the piping of the communication passage 45, a drill or a reamer can be inserted from a hole in one direction (for example, a hole drilled in the left wall of the first flow passage 41 in FIG. 6) for machining. This reduces the number of machining steps for the piping of the communication passage 45, thereby achieving cost reduction. In addition, machining is made easier, and errors in hole diameter and the like are reduced compared to machining the piping of the communication passage 45 by casting or the like, improving machining accuracy.

[0064] In the present embodiment, similarly to the first embodiment, the second communication passage 45b of the manifold 4 has a smaller flow passage area and a longer passage length than the first communication passage 45a, but this is not necessarily limited to this. For example, the flow passage areas and lengths of the first communication passage 45a and the second communication passage 45b may be equal to each other.

[0065] 8 of this embodiment, both the first communication passage 45a and the second communication passage 45b of the manifold 4 are formed in a linear cylindrical shape, but this is not limited thereto. For example, the entire communication passage 45 may be formed in a tapered shape as shown in Fig. 9. Even with this shape, as long as the central axes L of the first communication passage 45a and the second communication passage 45b are aligned in the same straight line, the piping of the communication passage 45 can be processed by inserting a drill or reamer through a hole in one direction.

[0066] Third embodiment A fuel cell system 100 according to a third embodiment will be described with reference to Fig. 10. Elements similar to those in the other embodiments are given the same reference numerals, and descriptions thereof will be omitted.

[0067] 10 is a top view of a manifold in a fuel cell system 100 according to a third embodiment. In this embodiment, the position of a communication passage 45 of a manifold 4 differs from that of the other embodiments.

[0068] As shown in FIG. 10, in the present embodiment as in the other embodiments, in the communicating passage 45 of the manifold 4, the flow path area of ​​the second communicating passage 45b is smaller than that of the first communicating passage 45a, and the second communicating passage 45b has a longer passage length than that of the first communicating passage 45a.

[0069] 10, the first communication passage 45a and the second communication passage 45b contact the surface of the flange 46 in a straight line (straight line M). Since the communication passage 45 contacts the surface of the flange 46 in a straight line in this manner, the plate thickness of the flange 46 can be made constant. This makes it possible to make uniform the surface pressure of the seal surface 462 of the flange 46 that contacts the fuel cell unit 10 when the manifold 4 is attached to the fuel cell unit 10. This improves the sealing performance at the connection points between the flow paths 41, 42, 43 of the manifold 4 and the cathode flow path in the fuel cell unit 10.

[0070] In this embodiment, as in the other embodiments, the second communication passage 45b of the manifold 4 has a smaller flow passage area and a longer passage length than the first communication passage 45a, but this is not necessarily limited to this. For example, the first communication passage 45a and the second communication passage 45b may have the same flow passage area and length.

[0071] (Fourth embodiment) A fuel cell system 100 according to a fourth embodiment will be described with reference to Figures 11 to 13. Elements similar to those in the other embodiments are given the same reference numerals, and descriptions thereof will be omitted.

[0072] 11 is a schematic diagram of a fuel cell system 100 according to a fourth embodiment. This embodiment differs from the other embodiments in that a manifold 4 is attached to a fuel cell unit 10 via a bracket 5.

[0073] As shown in FIG. 11, in this embodiment, a bracket 5 is attached to a housing 3 for fixing the fuel cell unit 10 to a vehicle in which a fuel cell system 100 is mounted.

[0074] The bracket 5 has a case-side fixing part 51 having a surface that abuts against the side surface on the outer periphery side of the housing 3, and an extension part 52 that is bent from the case-side fixing part 51 and extends in a direction approximately perpendicular to the side surface of the housing 3. The manifold 4 is attached to the surface of the case-side fixing part 51 opposite to the surface that abuts against the housing 3. As will be described later, the bracket 5 is fixed at the upper surface of the extension part 52 to a second bracket 7 that is attached to a side member 6 of a vehicle on which the fuel cell system 100 is mounted (see FIG. 13). A plurality of holes 53 that are hollowed out are formed on the lower surface of the extension part 52. This reduces the weight of the bracket 5. Furthermore, a compressor (air supply device) 8 is attached to the lower surface of the extension part 52 as a cathode gas supply source. The bracket 5 also has a gas supply port that connects to a gas flow path built into the auxiliary structure 2 via a gas supply port of the housing 3.

[0075] FIG. 12 is a schematic diagram of the fuel cell unit 10 (housing 3) with the manifold 4 and bracket 5 removed. As shown in FIG. 12, the housing 3 has gas supply ports, ie, a cathode gas supply port 31, a temperature adjustment gas supply port 32, and a reformed gas supply port 33, on one side surface. The main flow path 21, the bypass flow path 22, and the POX flow path 23 extending from the inside of the auxiliary structure 2 to the inner circumferential surface of the housing 3 are fixed to the housing 3 so as to be connected to the cathode gas supply port 31, the temperature adjustment gas supply port 32, and the reformed gas supply port 33, respectively. Meanwhile, the bracket 5 has a first through hole 54, a second through hole 55, and a third through hole 56 in the case side fixing part 51. The bracket 5 is attached so that the first through hole 54, the second through hole 55, and the third through hole 56 overlap the cathode gas supply port 31, the temperature adjustment gas supply port 32, and the reformed gas supply port 33 of the housing 3, respectively. As a result, the first through hole 54 and the cathode gas supply port 31, the second through hole 55 and the temperature control gas supply port 32, and the third through hole 56 and the reformed gas supply port 33 form holes through which the cathode gas, temperature control gas, and reformed gas pass, respectively.

[0076] As shown in FIG. 11, the manifold 4 has a flange 46 fixed to a case-side fixing portion 51 of the bracket 5. That is, the manifold 4 is fixed to the fuel cell unit 10 by fixing the flange 46 to the bracket 5. The manifold 4 is also attached to the bracket 5 so that the first flow passage 41 is connected to the first through hole 54 of the bracket 5, the second flow passage 42 is connected to the second through hole 55 of the bracket 5, and the third flow passage 43 is connected to the third through hole 56 of the bracket 5. Therefore, the first flow passage 41 of the manifold 4 is connected to the main flow passage 21 via the first through hole 54 of the bracket 5 and the cathode gas supply port 31 of the housing 3. Similarly, the second flow passage 42 of the manifold 4 is connected to the bypass flow passage 22 via the second through hole 55 of the bracket 5 and the temperature control gas supply port 32 of the housing 3, and the third flow passage 43 of the manifold 4 is connected to the POX flow passage 23 via the third through hole 56 of the bracket 5 and the reformed gas supply port 33 of the housing 3. The inlet 44 of the manifold 4 is connected to a compressor 8 via a pipe or a hose pipe or the like.

[0077] As shown in FIG. 12, a fixing portion 57 is formed in the bracket 5 so as to surround the first through hole 54, the second through hole 55, and the third through hole 56, and as shown in FIG. 11, the bracket 5 is fixed to the housing 3 at the fixing portion 57 by a bolt or the like.

[0078] Thus, the bracket 5 has a first through hole 54 connecting the first flow path 41 and the main flow path 21 of the manifold 4, a second through hole 55 connecting the second flow path 42 and the bypass flow path 22, and a third through hole 56 connecting the third flow path 43 and the POX flow path 23. Therefore, the bracket 5 for fixing the fuel cell unit 10 to the vehicle on which the fuel cell system 100 is mounted can also be used as a reinforcing material for the connection between the cathode flow paths 21, 22, 23 and the manifold 4. This allows the number of system components to be reduced, achieving weight reduction and cost reduction, compared to the case where a reinforcing material for the connection between the cathode flow paths 21, 22, 23 and the manifold 4 is separately provided. In addition, when the number of components attached to the housing 3 (fuel cell unit 10) increases, the amount of heat dissipated to the outside of the housing 3 through the components increases, but as described above, the number of components is reduced by using the bracket 5 also as a reinforcing material, and heat dissipation from the housing 3 can be suppressed.

[0079] Furthermore, since the fixing portion 57 that fixes the bracket 5 to the fuel cell unit 10 is formed so as to surround the first through hole 54, the second through hole 55, and the third through hole 56, the mounting rigidity and strength of the bracket 5 are improved and the mounting surface pressure is made uniform. This improves the sealing performance between the through holes 54, 55, and 56 of the bracket 5 and the cathode flow path in the fuel cell unit 10.

[0080] FIG. 13 is a schematic cross-sectional view of a vehicle equipped with a fuel cell system 100, as viewed from the front of the vehicle.

[0081] As shown in FIG. 13, a second bracket 7 is attached to a side member 6 of a vehicle. The bracket 5, which is fixed to the fuel cell unit 10, is fixed to the second bracket 7 on the upper surface of the extension portion 52. As a result, the fuel cell unit 10 is fixed to the vehicle via the bracket 5. Meanwhile, a compressor (air supply device) 8, which is a supply source of cathode gas, is attached to the lower surface of the extension portion 52. The compressor 8 is connected to the inlet 44 of the manifold 4 via a pipe or a hose pipe (see FIG. 11). By attaching the compressor 8 to the bracket 5 in this way, the distance from the compressor 8 to the manifold 4 and the cathode flow path is shorter than when the compressor 8 is attached to another position, and the distance of the pipes, etc. can be shortened. Therefore, the system can be made smaller, less expensive, and lighter. In addition, since the compressor 8 is attached to the lower surface of the bracket 5 (extension portion 52), the center of gravity is lowered, improving the maneuverability of the vehicle.

[0082] According to the fuel cell system 100 of the fourth embodiment described above, the following effects can be obtained.

[0083] The fuel cell system 100 is fixed to the vehicle via a bracket 5, and the manifold 4 is fixed to the fuel cell unit 10 by fixing a flange 46 formed so as to surround the first flow path 41, the second flow path 42, and the third flow path 43 to the bracket 5. The bracket 5 has a first through hole 54 connecting the first flow path 41 of the manifold 4 to the main flow path 21, a second through hole 55 connecting the second flow path 42 to the bypass flow path 22, and a third through hole 56 connecting the third flow path 43 to the POX flow path (partial reforming flow path) 23. A fixing portion 57 for fixing the bracket 5 to the fuel cell unit 10 is formed so as to surround the first through hole, the second through hole, and the third through hole. In this way, the bracket 5 for fixing the fuel cell unit 10 to the vehicle on which the fuel cell system 100 is mounted can also be used as a reinforcing material for the connection portion between the cathode flow paths 21, 22, and 23 and the manifold 4. This reduces the number of system parts, making the system lighter and less expensive than when a separate reinforcing material is provided for the connection between the cathode flow paths 21, 22, 23 and the manifold 4. Also, by using the bracket 5 as a reinforcing material, the number of parts is reduced, making it possible to suppress heat radiation from the fuel cell unit 10.

[0084] Furthermore, since the fixing portion 57 that fixes the bracket 5 to the fuel cell unit 10 is formed so as to surround the first through hole 54, the second through hole 55, and the third through hole 56, the mounting rigidity and strength of the bracket 5 are improved and the mounting surface pressure is made uniform. This improves the sealing performance between the through holes 54, 55, and 56 of the bracket 5 and the cathode flow path in the fuel cell unit 10.

[0085] In the fuel cell system 100, a compressor (air supply device) 8 serving as a cathode gas supply source is attached to the bracket 5. By attaching the compressor (air supply device) 8 to the bracket 5 in this manner, the distance from the compressor (air supply device) 8 to the manifold 4 and the cathode flow path is shorter than when the compressor (air supply device) 8 is attached to another position. This allows the distance of piping, etc. to be shortened, realizing a smaller, less costly, and more lightweight system.

[0086] It is preferable that the compressor (air supply device) 8 is attached to the lower surface of the extension portion 52 of the bracket 5 as in this embodiment, but this is not necessarily limited thereto, and the compressor (air supply device) 8 may be attached anywhere on the bracket 5.

[0087] In addition, in all of the embodiments, the fuel cell unit 10 is configured to include a housing 3 that houses the fuel cell stack 1 and the auxiliary structure 2, but this is not necessarily limited to this, and the fuel cell unit may not include a housing 3. In this case, the manifold 4 and bracket 5 are attached directly to the auxiliary structure 2.

[0088] In addition, in all the embodiments, the gas flow passages such as the heat exchanger and the cathode flow passage are built into the auxiliary structure 2, but this is not necessarily limited to this, and the auxiliary structure 2 may not be used.

[0089] Although the embodiments of the present invention have been described above, the above-mentioned embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-mentioned embodiments.

[0090] Although the above-described embodiments have been described as separate embodiments, they may be combined as appropriate.

Claims

1. A fuel cell system including a fuel cell unit including a fuel cell, an anode flow path that supplies an anode gas to the fuel cell, a cathode flow path that supplies a cathode gas to the fuel cell, and a heat exchanger that heats the cathode gas supplied to the fuel cell, a manifold attached to the fuel cell unit for distributing and supplying a cathode gas to the cathode flow passage; the cathode flow path includes a main flow path passing through the heat exchanger, a bypass flow path that bypasses the heat exchanger and is connected to the main flow path, and a partial reforming flow path that supplies a gas for partial oxidation reforming to the anode flow path, The manifold is configured as a gas distribution member including, in order from the upstream side, a first flow passage connected to the main flow passage, a second flow passage provided adjacent to the first flow passage and connected to the bypass flow passage, and a third flow passage provided adjacent to the second flow passage and connected to the partial reforming flow passage, and includes a communication passage including a first communication passage connecting the first flow passage and the second flow passage, and a second communication passage connecting the second flow passage and the third flow passage. Fuel cell system.

2. 2. The fuel cell system according to claim 1, The second communication passage has a smaller flow path cross-sectional area than the first communication passage. Fuel cell system.

3. 3. The fuel cell system according to claim 1, The communication passage is formed in a tapered shape so that the flow path becomes narrower toward the downstream. Fuel cell system.

4. 4. A fuel cell system according to claim 1, The second communication passage is longer than the first communication passage. Fuel cell system.

5. 5. A fuel cell system according to claim 1, The first communication passage and the second communication passage are configured so that their central axes in a flow direction of the cathode gas are aligned in the same straight line. Fuel cell system.

6. 6. A fuel cell system according to claim 1, the manifold includes at least one of a first control valve provided on the second flow path and configured to adjust an amount of cathode gas to be distributed to the bypass flow path, and a second control valve provided on the third flow path and configured to adjust an amount of cathode gas to be distributed to the partial reforming flow path. Fuel cell system.

7. 7. A fuel cell system according to claim 1, the manifold includes a flange formed to surround the first flow path, the second flow path, and the third flow path, The manifold has a flange fixed to the fuel cell unit. Fuel cell system.

8. 7. A fuel cell system according to claim 1, the fuel cell unit is fixed to a vehicle via a bracket; the manifold includes a flange formed to surround the first flow path, the second flow path, and the third flow path, and the manifold is fixed to the fuel cell unit by being fixed to the bracket, the bracket has a first through hole connecting the first flow passage of the manifold to the main flow passage, a second through hole connecting the second flow passage to the bypass flow passage, and a third through hole connecting the third flow passage to the partial reforming flow passage, a fixing portion that fixes the bracket to the fuel cell unit is formed to surround the first through hole, the second through hole, and the third through hole. Fuel cell system.

9. 9. The fuel cell system according to claim 8, An air supply device as a cathode gas supply source is attached to the bracket. Fuel cell system.

10. 10. The fuel cell system according to claim 7, the manifold includes a first control valve provided on the second flow path and configured to adjust an amount of cathode gas to be distributed to the bypass flow path, and a second control valve provided on the third flow path and configured to adjust an amount of cathode gas to be distributed to the partial reforming flow path, the flange has a flange fixing portion for fixing the manifold to the fuel cell unit, the flange fixing portion is formed to surround the first flow path, the second flow path, and the third flow path of the manifold. Fuel cell system.

11. 10. The fuel cell system according to claim 7, The flange has a uniform plate thickness, The first communication passage and the second communication passage of the manifold are in contact with the flange surface in a straight line. Fuel cell system.

12. 12. A fuel cell system according to any one of claims 1 to 11, the manifold includes a first control valve provided on the second flow path and configured to adjust an amount of cathode gas to be distributed to the bypass flow path, and a second control valve provided on the third flow path and configured to adjust an amount of cathode gas to be distributed to the partial reforming flow path, the first control valve includes a first valve body, a first valve cylinder fixed to the second flow path, and a first valve seat provided at a tip of the first valve cylinder, The second control valve includes a second valve body, a second valve cylinder fixed to the third flow path, and a second valve seat provided at a tip of the second valve cylinder. Fuel cell system.

13. 13. The fuel cell system of claim 12, the manifold is attached to the fuel cell unit such that an outlet of the second flow passage connected to the bypass flow passage and an outlet of the third flow passage connected to the partial reforming flow passage are on a lower side; the first valve seat and the second valve seat are located above bottoms of the first communication passage and the second communication passage, Fuel cell system.

14. 14. The fuel cell system according to claim 12 or 13, a cylindrical first housing surrounding an outer periphery of the first valve cylinder; a cylindrical second housing surrounding an outer periphery of the second valve cylinder, The first housing has an inner circumferential surface in contact with the first valve cylinder and an outer circumferential surface in contact with an inner circumferential surface of the second flow passage, The second housing has an inner circumferential surface in contact with the second valve cylinder and an outer circumferential surface in contact with an inner circumferential surface of the third flow passage. Fuel cell system.

15. 15. A fuel cell system according to any one of claims 12 to 14, The first valve cylinder is configured to be detachably attached to the second flow passage, The second valve cylinder is configured to be detachably attached to the third flow path. Fuel cell system.

16. 16. A fuel cell system according to any one of claims 12 to 15, The first valve cylinder is configured to be detachably attached to the second flow passage, The second valve cylinder is configured to be detachably attached to the third flow passage, The first valve body is attached to the second flow passage by being inserted into the second flow passage, the second valve body is attached to the third flow passage by being inserted into the third flow passage, The insertion directions of the first valve body and the second valve body are the same. Fuel cell system.

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