Fuel cell system

Abstract

This invention provides a technology for efficiently removing condensation water from a branched airflow channel, where the airflow channel is divided into multiple channels. [Solution] The fuel cell system 100 of this disclosure comprises an air supply unit 10, a hydrogen generator 30 that generates hydrogen-containing gas, a polymer electrolyte fuel cell 50 that generates electricity from the hydrogen-containing gas, an air channel 20 including a plurality of branch channels that guides air from the air supply unit 10 to the hydrogen generator 30 and the polymer electrolyte fuel cell 50, respectively, a flow rate adjustment unit 18 provided in the branch channel and positioned to receive heat from the outer surface of the hydrogen generator 30, and a storage unit 19 provided in the branch channel downstream of the flow rate adjustment unit 18 and positioned to receive heat from the outer surface of the hydrogen generator 30. In the vertical direction, the storage unit 19 is located below the flow rate adjustment unit 18.

Description

Technical Field

[0001] The present disclosure relates to a fuel cell system.

Background Art

[0002] Patent Document 1 discloses a fuel cell system having an air bleed mechanism that oxidizes and removes carbon monoxide (CO) by mixing air with a fuel gas. In the fuel cell system described in Patent Document 1, air is supplied to each of the cathode of the fuel cell, the anode of the fuel cell, and the fuel reforming unit (hydrogen generator) through an air flow adjustment unit.

[0003] Patent Document 2 discloses supplying air to both a fuel cell and a hydrogen generator from a single air supply unit. Air is supplied to the hydrogen generator through a flow adjustment unit having a first orifice and a second orifice.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In fuel cell systems equipped with a hydrogen generator and fuel cell, high-humidity gases flow through the flow paths during operation. Therefore, when the fuel cell system is shut down, residual water vapor may cause condensation to form inside the piping that makes up the flow paths. If the fuel cell system is restarted while condensation is present, the air flow rate in each flow path may deviate from the design value. If the air flow rate deviates from the design value, it may become difficult to oxidize and remove CO at the fuel cell anode due to insufficient air, or abnormal reactions may occur due to excessive air flow rate supplied to the hydrogen generator, or excessive air flow rate supplied to the fuel cell cathode. In some cases, the fuel cell system may shut down or the lifespan of the device may be shortened. This problem is more likely to become apparent in branched flow paths where the air flow path branches into multiple paths.

[0006] In view of the above circumstances, this disclosure aims to provide a technology for efficiently removing condensation water from a branched airflow channel in which an airflow channel is divided into multiple channels. [Means for solving the problem]

[0007] This disclosure is, Air supply unit, A hydrogen generator that produces hydrogen-containing gas, A solid polymer fuel cell that generates electricity from the hydrogen-containing gas, An air channel including multiple branching channels that guides air from the air supply to the hydrogen generator and the polymer electrolyte fuel cell, A flow rate adjustment unit is provided in the aforementioned branch channel and is positioned to receive heat from the outer surface of the hydrogen generation device, A storage unit is provided in the branch channel downstream of the flow rate adjustment unit and is arranged to receive heat from the outer surface of the hydrogen generator, Equipped with, In the vertical direction, the storage unit is located below the flow rate adjustment unit, providing a fuel cell system. [Effects of the Invention]

[0008] According to the technology disclosed herein, condensation water can be efficiently removed from branched airflow channels in which an airflow channel is divided into multiple channels. [Brief explanation of the drawing]

[0009] [Figure 1] Configuration diagram of the fuel cell system in Embodiment 1 [Figure 2] A perspective view showing an example of part II in Figure 1. [Figure 3] Side view of Figure 2 [Figure 4] Cross-sectional view of section IV in Figure 2 [Figure 5] A perspective view showing an example of a storage section together with a flow rate adjustment section. [Figure 6] A perspective view showing another example of a storage section along with a flow rate adjustment section. [Figure 7] A perspective view showing yet another example of a storage section, along with a flow rate adjustment section. [Figure 8] A perspective view showing yet another example of a storage section, along with a flow rate adjustment section. [Figure 9] Configuration diagram of the fuel cell system in Embodiment 2 [Figure 10] Configuration diagram of the fuel cell system in Embodiment 3 [Modes for carrying out the invention]

[0010] The embodiments will be described in detail below with reference to the drawings. However, unnecessary details may be omitted. For example, detailed explanations of already well-known matters or redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding for those skilled in the art.

[0011] The attached drawings and the following description are provided to enable the parties to fully understand this disclosure and are not intended to limit the subject matter described in the claims.

[0012] (Embodiment 1) Hereinafter, Embodiment 1 will be described with reference to FIGS. 1 to 8.

[0013] [1-1. Configuration] FIG. 1 is a configuration diagram of a fuel cell system 100 according to Embodiment 1. The fuel cell system 100 includes an air supply unit 10, a hydrogen generation device 30, a fuel cell 50, an air flow path 20, a flow rate adjustment unit 18, and a storage unit 19. The air flow path 20 includes a plurality of branch flow paths. Through the air flow path 20, air G1 is supplied from the air supply unit 10 to each of the hydrogen generation device 30 and the fuel cell 50. The flow rate adjustment unit 18 and the storage unit 19 are provided in the branch flow path of the air flow path 20 and are arranged so as to receive heat from the outer surface of the hydrogen generation device 30. In the branch flow path, the storage unit 19 is provided on the downstream side of the flow rate adjustment unit 18.

[0014] FIG. 2 is a perspective view showing an example of the II portion in FIG. 1. FIG. 3 is a side view of FIG. 2. In the example of FIGS. 2 to 3, the Z direction is the vertical direction, and the X direction is the horizontal direction perpendicular to the vertical direction. The Y direction is the direction perpendicular to the Z direction and the X direction. Hereinafter, as shown in FIGS. 2 to 3, the hydrogen generation device 30 in which the central axis Ax of the hydrogen generation device 30 is placed parallel to the Z direction which is the vertical direction may be referred to as the vertically placed hydrogen generation device 30. In the fuel cell system 100, the hydrogen generation device 30 is installed so as to be in a vertical state.

[0015] In this embodiment, the storage section 19 is located below the flow rate adjustment section 18 in the vertical direction. This configuration allows for efficient removal of condensation water from the branched flow path where the flow rate adjustment section 18 and the storage section 19 are located. First, the flow rate adjustment section 19 is heated by heat conduction from the outer surface of the hydrogen generator 30. This causes the condensation water accumulated in the flow rate adjustment section 19 to evaporate and be removed. Any condensation water that could not be evaporated in the flow rate adjustment section 19 flows into the storage section 19, which is located downstream of the flow rate adjustment section 19. Next, the storage section 19 is heated by heat conduction from the outer surface of the hydrogen generator 30. This causes the condensation water accumulated in the storage section 19 to evaporate and be removed. According to this embodiment, additional equipment such as electric heaters for removing condensation water can be omitted. In that case, the control of the additional equipment can also be omitted.

[0016] In this embodiment, the flow rate adjustment unit 18 and the storage unit 19 are arranged to receive heat from the outer surface of the hydrogen generator 30, and are heated by heat conduction without passing through the branched flow path. However, at least one of the flow rate adjustment unit 18 and the storage unit 19 may be arranged to receive heat by heat conduction from the outer surface of the hydrogen generator 30.

[0017] In this embodiment, "In the vertical direction, the storage section 19 is located below the flow rate adjustment section 18" means, as shown in Figure 3, that in the vertical hydrogen generator 30, the height H19 of the storage section 19 is smaller than the height H18 of the flow rate adjustment section 18. The height H19 of the storage section 19 is defined as the vertical distance from the bottom surface 30s of the hydrogen generator 30 to the lowest point 19m of the storage section 19. The height H18 of the flow rate adjustment section 18 is defined as the vertical distance from the bottom surface 30s of the hydrogen generator 30 to the lowest point 18m of the central axis Ax18 of the flow rate adjustment section 18. The bottom surface 30s of the hydrogen generator 30 is usually in contact with the installation surface, such as the floor.

[0018] The difference between the height H19 of the storage section 19 and the height H18 of the flow rate adjustment section 18 (H18-H19) is set appropriately according to the height of the hydrogen generator 30, etc. For example, the difference between height H19 and height H18 (H18-H19) may be in the range of 1 cm to 15 cm.

[0019] The air supply unit 10 is a device for supplying air G1 to the hydrogen generator 30 and the fuel cell 50. The air supply unit 10 is, for example, a blower. The air supply unit 10 may be configured to allow flow rate adjustment. The air G1 is used in the selective oxidation reaction in the hydrogen generator 30, as an oxidizing gas in the cathode 51 of the fuel cell 50, and in the anode 52 of the fuel cell 50 to oxidize and remove CO remaining in the hydrogen-containing gas G3.

[0020] The hydrogen generator 30 is a device for generating hydrogen-containing gas G3 from a mixed gas G2 containing a raw material gas and water. The raw material gas includes hydrocarbon gases such as methane gas. In this embodiment, the hydrogen generator 30 includes a reformer 31, a CO reducer 32, and a CO remover 33. The reformer 31 is responsible for generating hydrogen-containing gas G3 from the mixed gas G2 through a reforming reaction. The CO reducer 32 is responsible for reducing the concentration of CO in the hydrogen-containing gas G3 through a denaturation reaction. The CO remover 33 is responsible for further reducing the concentration of CO in the hydrogen-containing gas G3 through a selective oxidation reaction. A relay channel 34 is provided between the CO reducer 32 and the CO remover 33. The relay channel 34 is a channel for guiding the hydrogen-containing gas G3 from the CO reducer 32 to the CO remover 33.

[0021] The hydrogen generator 30 further comprises a container 35. The reformer 31, CO reducer 32, and CO remover 33 are housed in the container 35. During operation of the hydrogen generator 30, a heating unit (not shown) located inside the container 35 maintains the temperature inside the container 35 at a temperature suitable for each reaction. As a result, the outer surface of the container 35 becomes heated. In the vertically positioned hydrogen generator 30, the temperature of the outer surface of the container 35 tends to rise from top to bottom.

[0022] In this embodiment, the container 35 is made of metal such as stainless steel. The flow rate adjustment unit 18 and the storage unit 19 may be in contact with the outer surface of the container 35. By directly contacting the flow rate adjustment unit 18 and the storage unit 19 with the outer surface of the metal container 35, heat from the container 35 can be efficiently transferred to the flow rate adjustment unit 18 and the storage unit 19.

[0023] It is desirable that the flow rate adjustment unit 18 be heated to a temperature within the range of T1, the temperature at which condensation water evaporates, and T2, the temperature within which the internal flow path dimensions of the flow rate adjustment unit 18 are not significantly affected. It is desirable that the storage unit 19 be heated to a temperature within the range of T3, the temperature at which condensation water evaporates, and T3, the temperature within which the internal flow path dimensions of the storage unit 19 are not significantly affected, and at a temperature of T2 or higher. The temperature T1 at which condensation water evaporates is, for example, 100°C. The temperature T2 is, for example, in the range of 150°C to 200°C. The temperature T3 is, for example, in the range of 220°C to 270°C. When the hydrogen generator 30 is in operation, the internal temperature T2 of the flow rate adjustment unit 18 may be in the range of 150°C to 200°C, and the internal temperature T3 of the storage unit 19 may be in the range of 220°C to 270°C. With such a configuration, condensation water can be efficiently removed when the hydrogen generator 30 is in operation.

[0024] During operation of the hydrogen generator 30, the temperature difference T2 inside the flow rate adjustment unit 18 and the temperature T3 inside the storage unit 19 may be in the range of 20°C to 30°C. With this configuration, condensation water can be removed stably.

[0025] On the other hand, the temperature of the hydrogen-containing gas G3 flowing through the CO reducer 32, the relay channel 34, and the CO remover 33 is in the range of 100°C to 300°C. Such temperatures are suitable for heating the flow rate adjustment unit 18 to a temperature T2 within the above numerical range, and for heating the storage unit 19 to a temperature T3 within the above numerical range. This also applies to embodiments 2 and 3 described later.

[0026] The hydrogen generator 30 is connected to the fuel cell 50 by an anode gas channel 40. Hydrogen-containing gas G3 is supplied from the hydrogen generator 30 to the anode 52 of the fuel cell 50 through the anode gas channel 40.

[0027] The fuel cell 50 is a device for generating electricity from hydrogen-containing gas G3 and an oxidizing gas. The oxidizing gas is air G1. In this embodiment, the fuel cell 50 is a polymer electrolyte fuel cell. When the fuel cell 50 is a polymer electrolyte fuel cell, it is necessary to sufficiently reduce the CO concentration in the hydrogen-containing gas G3 in order to suppress catalyst degradation. Air G1 is used to oxidize and remove CO in the hydrogen generation device 30 and the anode 52 of the fuel cell 50.

[0028] The air passage 20 is a passage for guiding air from the air supply unit 10 to the hydrogen generator 30 and the fuel cell 50, respectively. The air passage 20 includes a common passage 21, a first branch passage 12, and a second branch passage 14. The common passage 21 is connected to the air supply unit 10. At the branching section 11, the common passage 21 branches into the first branch passage 12 and the second branch passage 14. The branching section 11 is, for example, a T-joint. With this configuration, air G1 can be supplied from the common air supply unit 10 to each of the first branch passage 12 and the second branch passage 14. Each part of the air passage 20 is composed of one or more pipes. In this embodiment, the cross-section of the pipe is circular.

[0029] The first branch channel 12 is a channel that guides air G1 to the cathode 51 of the fuel cell 50. The first branch channel 12 connects the branch section 11 and the cathode 51 of the fuel cell 50. Air G1 is supplied to the cathode 51 via the first branch channel 12. The second branch channel 14 is a channel that guides air G1 to the hydrogen generator 30 and the anode 52 of the fuel cell 50.

[0030] In this embodiment, a flow rate adjustment unit 18 and a storage unit 19 are provided in the second branch channel 14. With this configuration, condensation water can be efficiently removed from the second branch channel 14.

[0031] In this embodiment, the second branch channel 14 includes a third branch channel 14a and a fourth branch channel 14b and a fifth branch channel 14c that branch off from the branching section 17 in the third branch channel 14a. In other words, the second branch channel 14 further branches into the fourth branch channel 14b and the fifth branch channel 14c at the branching section 17. The piping for the fourth branch channel 14b and the piping for the fifth branch channel 14c open toward the third branch channel 14a. This forms the branching section 17. The branching section 17 is, for example, a T-joint. With this configuration, air G1 can be supplied from a common air supply unit 10 to each of the fourth branch channel 14b and the fifth branch channel 14c.

[0032] The fourth branch channel 14b is an introduction channel that guides air G1 into the relay channel 34 of the hydrogen generator 30. The fourth branch channel 14b merges with the relay channel 34 at a junction 37 inside the hydrogen generator 30. The relay channel 34 is, for example, a space inside the hydrogen generator 30. The piping as the fourth branch channel 14b opens toward the relay channel 34. This forms the junction 37. The fifth branch channel 14c merges with the anode gas channel 40 at a junction 41. The fifth branch channel 14c is a so-called air bleed channel. The junction 41 is, for example, a T-joint.

[0033] In this embodiment, a flow rate adjustment unit 18 and a storage unit 19 are provided in the fifth branch channel 14c, which is an air bleed channel. With this configuration, the distribution between the fourth branch channel 14b and the fifth branch channel 14c can be appropriately adjusted. In other words, the flow rate of air G1 supplied to the hydrogen generator 30 and the flow rate of air G1 supplied to the anode 52 of the fuel cell 50 can be appropriately adjusted. As a result, the concentration of CO in the hydrogen-containing gas G3 can be appropriately reduced, and the deterioration of the catalyst at the anode 52 of the fuel cell 50 can be suppressed.

[0034] In this embodiment, in the vertical direction, the storage section 19 is located at the bottom of the fifth branch channel 14c, which is an air bleed channel. As described above, in the vertical hydrogen generator 30, the temperature of the outer surface of the container 35 of the hydrogen generator 30 tends to rise from top to bottom. Therefore, with this configuration, the storage section 19 can be heated to a higher temperature. In addition, it is possible to suppress the outflow of condensed water accumulated in the storage section 19 to the downstream side of the storage section 19. As a result, the condensed water accumulated in the storage section 19 can be evaporated and removed more efficiently.

[0035] In this embodiment, "In the vertical direction, the storage section 19 is located at the lowest point of the branch channel 14c" means that, as shown in Figure 3, in the vertical hydrogen generation device 30, the lowest point 19m of the storage section 19 and the lowest point 14cm of the fifth branch channel 14c coincide.

[0036] The flow rate adjustment section 18 is, for example, an orifice. In this case, the ratio of the flow rate of air G1 in the fourth branch channel 14b to the flow rate of air G1 in the fifth branch channel 14c can be a design value. Such a configuration does not require control for flow rate adjustment, but it is susceptible to the effects of condensation. Therefore, according to the configuration of this embodiment, the effect of removing condensation from the flow rate adjustment section 18 with the heat of the hydrogen generator 30 is significant.

[0037] In this embodiment, the flow rate adjustment section 18 is located below the branch section 17 in the vertical direction. With this configuration, condensation water generated upstream of the branch section 17 can easily flow into the flow rate adjustment section 19 through the fifth branch channel 14c. Therefore, it is possible to suppress the flow of condensation water into the fourth branch channel 14b, which guides air G1 into the hydrogen generator 30.

[0038] In this embodiment, "in the vertical direction, the flow rate adjustment section 18 is located below the branching section 17" means, as shown in Figure 3, that in the vertical hydrogen generator 30, the height H18 of the flow rate adjustment section 18 is smaller than the height H17 of the branching section 17. The height H17 of the branching section 17 is defined as the vertical distance from the lower surface 30s of the hydrogen generator 30 to the intersection point 17i of the opening 14p of the fifth branching channel 14c in the branching section 17 and the central axis Ax17 of the fifth branching channel 14c in the branching section 17.

[0039] The difference between the height H18 of the flow rate adjustment section 18 and the height H17 of the branching section 17 (H17-H18) is set appropriately according to the height of the hydrogen generator 30, etc. For example, the difference between height H18 and height H17 (H17-H18) may be in the range of 5 cm to 19 cm.

[0040] In this embodiment, flow meters are not provided in the fourth branch channel 14b and the fifth branch channel 14c. In this case, control to adjust the flow rate of air G1 in the fourth branch channel 14b and the fifth branch channel 14c based on the detection results of the flow meters can be omitted.

[0041] The flow rate adjustment unit 18 and the storage unit 19 may be in contact with the hydrogen generator 30 at a position facing at least one selected from the CO reducer 32, the intermediate flow path 34, and the CO remover 33. When the flow rate adjustment unit 18 and the storage unit 19 are arranged in such a position, it is easier to heat the flow rate adjustment unit 18 to a temperature T2 within the above numerical range and the storage unit 19 to a temperature T3 within the above numerical range.

[0042] In this embodiment, the storage section 19 is located below the confluence section 41 in the vertical direction. With this configuration, it is possible to suppress the inflow of condensed water accumulated in the storage section 19 into the anode gas flow path 40.

[0043] In this embodiment, "In the vertical direction, the storage section 19 is located below the confluence section 41" means, as shown in Figure 3, that in the vertical hydrogen generator 30, the height H19 of the storage section 19 is smaller than the height H41 of the confluence section 41. The height H41 of the confluence section 41 is defined in the same way as the height H17 of the branch section 17 described above. That is, the height H41 of the confluence section 41 is the vertical distance from the lower surface 30s of the hydrogen generator 30 to the intersection point 41i of the opening 14q of the fifth branch channel 14c in the confluence section 41 and the central axis Ax41 of the fifth branch channel 14c in the confluence section 41.

[0044] The difference between the height H19 of the storage section 19 and the height H41 of the confluence section 41 (H41-H19) is set appropriately according to the height of the hydrogen generator 30, etc. For example, the difference between height H19 and height H41 (H41-H19) may be in the range of 6 cm to 20 cm.

[0045] The height H41 of the confluence section 41 may be equal to the height H17 of the branching section 17, or it may be greater than the height H17 of the branching section 17. In the example in Figure 3, the height H41 of the confluence section 41 is greater than the height H17 of the branching section 17.

[0046] As shown in Figure 2, in the fifth branch channel 14c, the portion from the branch section 17 to the storage section 19 is defined as the upstream portion 14c1, and the portion from the storage section 19 to the confluence section 41 is defined as the downstream portion 14c2. In this embodiment, the upstream portion 14c1 is a straight section extending diagonally downward from the branch section 17 toward the storage section 19. A flow rate adjustment section 18 is provided in the upstream portion 14c1. The downstream portion 14c2 has a straight section extending diagonally upward from the storage section 19 toward the bend section 14cf, and a straight section extending horizontally from the bend section 14cf toward the confluence section 41. With this configuration, it is easy to connect the fifth branch channel 14c to the confluence section 41.

[0047] Figure 4 is a cross-sectional view of section IV in Figure 2, showing the confluence section 41 and its vicinity. Figure 4 is a cross-sectional view in the confluence section 41 that passes through and is parallel to the central axis Ax41 of the fifth branch channel 14c. As shown in Figure 4, in this embodiment, in the confluence section 41, the direction in which the central axis Ax40 of the anode gas channel 40 extends is the X direction, and the direction in which the central axis Ax41 of the fifth branch channel 14c extends is the Y direction, which is perpendicular to the X direction.

[0048] In this embodiment, in the vertical direction, the lowest point 14m of the inner surface of the fifth branch channel 14c in the confluence section 41 is located above the lowest point 40m of the inner surface of the anode gas channel 40 in the confluence section 41. With this configuration, it is possible to further suppress the inflow of condensed water accumulated in the storage section 19 into the anode gas channel 40.

[0049] In the vertical direction, the distance D between the lowest point (14m) and the lowest point (40m) is set appropriately according to the pipe diameter, etc. For example, the distance D may be 25% or more of the pipe diameter.

[0050] The structure of the downstream portion 14c2 of the fifth branch channel 14c is not limited to the examples shown in Figures 2 and 3. For example, the downstream portion 14c2 may not have a bend 14cf, but may be a straight section extending diagonally upward from the storage section 19 toward the confluence section 41. In this case as well, it is desirable that, in the vertical direction, the lowest point 14m of the inner surface of the fifth branch channel 14c at the confluence section 41 is located above the lowest point 40m of the inner surface of the anode gas channel 40 at the confluence section 41.

[0051] In the example shown in Figures 2 and 3, the storage section 19 is a roughly rectangular parallelepiped container 19a positioned between the upstream section 14c1 and the downstream section 14c2. The cross-sectional area of ​​the flow path of the container 19a is larger than the cross-sectional area of ​​the flow path of the fifth branched flow path 14c. However, the configuration of the storage section 19 is not particularly limited as long as it can store condensed water.

[0052] Figures 5 to 8 show several examples of the storage section 19. As shown in Figure 5, the storage section 19 may be the connection section between the upstream section 14c1 and the downstream section 14c2 itself. That is, the storage section 19 may be the bent section where the fifth branch channel 14c is bent into a V shape. Condensed water W is stored in the V-shaped bent section. As shown in Figure 6, the storage section 19 may be the straight section connecting the upstream section 14c1 and the downstream section 14c2. Condensed water W is stored in the straight section. As shown in Figure 7, the storage section 19 may be a V-shaped container 19b located between the upstream section 14c1 and the downstream section 14c2. The cross-sectional area of ​​the channel of the container 19b is larger than the cross-sectional area of ​​the channel of the fifth branch channel 14c. Condensed water W is stored in the container 19b. As shown in Figure 8, the storage section 19 may be a cylindrical container 19c located between the upstream section 14c1 and the downstream section 14c2. The cross-sectional area of ​​the flow path in container 19c is larger than the cross-sectional area of ​​the flow path in the fifth branch flow path 14c. Condensed water W is stored in container 19c.

[0053] The capacity of the storage section 19 is set appropriately according to the cross-sectional area of ​​the fifth branch channel 14c, etc.

[0054] In this embodiment, the third branch channel 14a is provided with a flow rate adjustment unit 13 and a flow meter 15 in the portion between the branch section 11 and the branch section 17. In this embodiment, unlike the flow rate adjustment unit 18, the flow rate adjustment unit 13 is not positioned to receive heat from the outer surface of the hydrogen generator 30 by heat conduction. However, by controlling the flow rate adjustment unit 13 based on the detection result of the flow meter 15, the flow rate of air G1 in the third branch channel 14a can be adjusted to a desired flow rate.

[0055] As shown in Figure 1, the fuel cell system 100 may further include an insulating member 36. The insulating member 36 integrally covers the flow rate adjustment unit 18, the storage unit 19, and the hydrogen generator 30. With this configuration, heat from the hydrogen generator 30 can be efficiently transferred to the flow rate adjustment unit 18 and the storage unit 19 while suppressing heat dissipation from the hydrogen generator 30 to the ambient atmosphere. In the example in Figure 1, the container 35 of the hydrogen generator 30, the flow rate adjustment unit 18, and the storage unit 19 are covered by the insulating member 36. Examples of materials for the insulating member 36 include glass wool. For convenience, the insulating member 36 is omitted in Figures 2 and 3.

[0056] [1-2. Operation] The operation of the fuel cell system 100, configured as described above, will now be explained.

[0057] When the air supply unit 10 is activated, air G1 is supplied to the hydrogen generator 30 and the fuel cell 50, respectively, through the air passage 20.

[0058] A mixed gas G2 containing raw material gas and water is supplied to the hydrogen generator 30. The water vaporizes inside the hydrogen generator 30. The raw material gas and water vapor are supplied to the reformer 31 to produce hydrogen-containing gas G3. The hydrogen-containing gas G3 is supplied to the CO reducer 32. In the CO reducer 32, the concentration of CO in the hydrogen-containing gas G3 is reduced by a denaturation reaction. The hydrogen-containing gas G3 with reduced CO concentration is supplied to the CO remover 33 via the relay channel 34. In the relay channel 34, air G1 is mixed with the hydrogen-containing gas G3 from the fourth branch channel 14b. The CO remover 33 further reduces the concentration of CO in the hydrogen-containing gas G3 by a selective oxidation reaction. Specifically, the selective oxidation reaction of chemical formula (1) and the reaction of chemical formula (2) occur in the CO remover 33.

[0059] 2CO + O2 → 2CO2···(1) 2H2 + O2 → 2H2O···(2)

[0060] The hydrogen-containing gas G3, with its CO concentration further reduced, is supplied from the hydrogen generator 30 to the anode 52 of the fuel cell 50 via the anode gas flow path 40. In the anode gas flow path 40, air G1 is mixed with the hydrogen-containing gas G3 via the fifth branch flow path 14c. At the anode 52 of the fuel cell 50, the CO is oxidized by the air contained in the hydrogen-containing gas G3. This suppresses the degradation of the catalyst at the anode 52 of the fuel cell 50.

[0061] In this embodiment, in the fifth branch channel 14c, first, the flow rate adjustment unit 19 is heated by heat conduction from the outer surface of the hydrogen generator 30. As a result, the condensed water accumulated in the flow rate adjustment unit 19 evaporates and is removed. The condensed water that does not evaporate in the flow rate adjustment unit 19 flows into the storage unit 19 located downstream of the flow rate adjustment unit 19. Next, the storage unit 19 is heated by heat conduction from the outer surface of the hydrogen generator 30. As a result, the condensed water accumulated in the storage unit 19 evaporates and is removed. As a result, condensed water can be efficiently removed from the fifth branch channel 14c.

[0062] Air G1, acting as an oxidizing gas, is supplied to the cathode 51 of the fuel cell 50 through the first branch channel 12. The fuel cell 50 generates electricity using hydrogen-containing gas G3 and the oxidizing gas.

[0063] (Embodiment 2) Embodiment 2 will be described below with reference to Figure 9.

[0064] [2-1. Structure] Figure 9 is a diagram showing the configuration of the fuel cell system 102 of Embodiment 2. In the fuel cell system 102 of this embodiment, a flow rate adjustment unit 18 and a storage unit 19 are provided in the fourth branch channel 14b for supplying air G1 to the relay channel 34 located between the CO reducer 32 and the CO remover 33. Except for this point, the configuration of the fuel cell system 102 is the same as that of the fuel cell system 100 of Embodiment 1. According to the fuel cell system 102, condensation water can be efficiently removed from the fourth branch channel 14b.

[0065] Similar to Embodiment 1, in this embodiment as well, the distribution between the fourth branch channel 14b and the fifth branch channel 14c can be appropriately set. In other words, the flow rate of air G1 supplied to the hydrogen generator 30 and the flow rate of air G1 supplied to the anode 52 of the fuel cell 50 can be appropriately adjusted. As a result, the concentration of CO in the hydrogen-containing gas can be appropriately reduced, and the degradation of the catalyst at the anode 52 of the fuel cell 50 can be suppressed.

[0066] The airflow rate required for the fifth branch channel 14c often exceeds the airflow rate required for the fourth branch channel 14b. Given this relationship in flow rates, it is common to provide a flow rate adjustment section 19 in the fourth branch channel 14b. Furthermore, because the fourth branch channel 14b is a channel with a low airflow rate, it is more susceptible to condensation. Therefore, the technology of this disclosure is particularly useful when a flow rate adjustment section 18 and a storage section 19 are provided in the fourth branch channel 14b.

[0067] Although not shown in the diagram, a flow rate adjustment section 18 and a storage section 19 may be provided in both the fourth branch channel 14b and the fifth branch channel 14c. In this case, the two flow rate adjustment sections 18 and the two storage sections 19 may be arranged to receive heat from the outer surface of the hydrogen generator 30 by heat conduction.

[0068] (Embodiment 3) Embodiment 3 will be described below with reference to Figure 10.

[0069] [3-1. Structure] Figure 10 is a configuration diagram of the fuel cell system 104 of Embodiment 3. In this embodiment, the fuel cell system 104 is positioned such that the flow rate adjustment unit 13, which is provided in the second branch channel 14, receives heat from the outer surface of the hydrogen generator 30 by heat conduction. More specifically, the flow rate adjustment unit 13 is provided in the second branch channel 14 between the branch section 11 and the branch section 17. According to this embodiment, since the flow rate adjustment unit 13 is heated by the hydrogen generator 30, any condensed water accumulated in the flow rate adjustment unit 13 can be evaporated and removed. This allows air G1 to be supplied to both the hydrogen generator 30 and the fuel cell 50 at a desired flow rate.

[0070] In this embodiment, not only the flow rate adjustment unit 13, but also the flow rate adjustment unit 18 and the storage unit 19 are arranged to receive heat from the outer surface of the hydrogen generator 30 by heat conduction. In this way, Embodiment 1 and Embodiment 3 can be combined. Similarly, Embodiment 2 and Embodiment 3 can be combined.

[0071] (others) In embodiments 1 to 3, it is not essential that the flow rate adjustment section 13, the flow rate adjustment section 18, and the storage section 19 are in direct contact with the container 35 of the hydrogen generator 30. For example, a heat transfer assisting member may be placed between the flow rate adjustment section 13, the flow rate adjustment section 18, and the storage section 19 and the container 35 of the hydrogen generator 30. In this case, heat from the hydrogen generator 30 can be conducted to the flow rate adjustment section 13, the flow rate adjustment section 18, and the storage section 19 through the heat transfer assisting member. Examples of heat transfer assisting members include heat-resistant heat conductive sheets such as carbon sheets and fluororesin sheets.

[0072] In Embodiment 1, in the examples shown in Figures 2 to 4, the second branch channel 14 extends in the +Z direction, and the anode gas channel 40 extends in the +X direction. However, the direction in which the second branch channel 14 and the anode gas channel 40 extend are not limited to the examples shown in Figures 2 to 4. For example, both the second branch channel 14 and the anode gas channel 40 may extend in the +Y direction. For example, the second branch channel 14 may extend in the -Z direction. For example, the anode gas channel 40 may extend in the -X direction.

[0073] In embodiments 1 to 3, the cross-sections of the pipes constituting each part of the air passage 20 are circular. However, the cross-section is not limited to a circular shape; for example, it may be polygonal.

[0074] [4. Addendum] Based on the above description of embodiments, the following technologies are disclosed.

[0075] (Technology 1) Air supply unit, A hydrogen generator that produces hydrogen-containing gas, A solid polymer fuel cell that generates electricity from the hydrogen-containing gas, An air channel including multiple branching channels that guides air from the air supply to the hydrogen generator and the polymer electrolyte fuel cell, A flow rate adjustment unit is provided in the aforementioned branch channel and is positioned to receive heat from the outer surface of the hydrogen generation device, A storage unit is provided in the branch channel downstream of the flow rate adjustment unit and is arranged to receive heat from the outer surface of the hydrogen generator, Equipped with, A fuel cell system in which, in the vertical direction, the storage section is located below the flow rate adjustment section.

[0076] According to the fuel cell system of Technology 1, condensation water can be efficiently removed from the branched flow path.

[0077] (Technology 2) The fuel cell system according to Technology 1, wherein the plurality of branched channels include a first branched channel that guides the air to the cathode of the polymer electrolyte fuel cell and a second branched channel that guides the air to the hydrogen generator, and the flow rate adjustment unit and the storage unit are provided in the second branched channel. With this configuration, condensation water can be efficiently removed from the second branched channel.

[0078] (Technology 3) The fuel cell system according to Technology 2, wherein the second branch channel includes a third branch channel and an air bleed channel that branches off from the branching portion in the third branch channel and guides the air to the anode of the polymer electrolyte fuel cell, and the flow rate adjustment section and the storage section are provided in the air bleed channel. With such a configuration, the distribution between the multiple branch channels can be appropriately adjusted.

[0079] (Technology 4) In the vertical direction, the storage section is located at the bottom of the air bleed passage in the fuel cell system according to Technology 3. With this configuration, the condensed water accumulated in the storage section can be evaporated and removed more efficiently.

[0080] (Technology 5) A fuel cell system according to Technology 3 or 4, wherein in the vertical direction, the flow rate adjustment section is located below the branch section. With such a configuration, for example, it is possible to suppress the inflow of condensation water into the branch channel that guides air into the hydrogen generation device.

[0081] (Technology 6) A fuel cell system according to any one of the technologies 3 to 5, further comprising an anode gas channel for guiding the hydrogen-containing gas from the hydrogen generator to the anode of the polymer electrolyte fuel cell, wherein the air bleed channel merges with the anode gas channel at a confluence, and the storage section is located below the confluence in the vertical direction. With such a configuration, it is possible to suppress the inflow of condensed water accumulated in the storage section into the anode gas channel.

[0082] (Technology 7) The fuel cell system according to Technology 6, wherein, in the vertical direction, the lowest point of the inner surface of the air bleed passage at the confluence is located above the lowest point of the inner surface of the anode gas passage at the confluence. With this configuration, it is possible to further suppress the inflow of condensed water accumulated in the storage section into the anode gas passage.

[0083] (Technology 8) The hydrogen generation device includes a CO reducer that reduces the concentration of carbon monoxide in the hydrogen-containing gas by a denaturation reaction, a CO remover that further reduces the concentration of carbon monoxide in the hydrogen-containing gas by a selective oxidation reaction, and a relay channel that guides the hydrogen-containing gas from the CO reducer to the CO remover, and the second branch channel includes a third branch channel and an introduction channel that branches off from the branching section of the third branch channel and guides the air to the relay channel, and the flow rate adjustment section and the storage section are provided in the introduction channel, the fuel cell system according to Technology 2. With such a configuration, condensation water can be efficiently removed from the introduction channel.

[0084] (Technology 9) A fuel cell system according to any one of the technologies 1 to 8, further comprising a heat insulating member that integrally covers the flow rate adjustment unit, the storage unit, and the hydrogen generation device. With such a configuration, heat from the hydrogen generation device can be efficiently transferred to the flow rate adjustment unit and the storage unit while suppressing heat dissipation from the hydrogen generation device to the ambient atmosphere.

[0085] (Technology 10) A fuel cell system according to any one of the Technical Claims 1 to 9, wherein the hydrogen generation device includes a metal container, the outer surface is the outer surface of the container, and the flow rate adjustment unit and the storage unit are in contact with the outer surface of the container. With such a configuration, heat from the container can be efficiently transferred to the flow rate adjustment unit and the storage unit.

[0086] (Technology 11) A fuel cell system according to any one of the technologies 1 to 10, wherein, during operation of the hydrogen generation device, the internal temperature of the flow rate adjustment section is in the range of 150°C to 200°C, and the internal temperature of the storage section is in the range of 220°C to 270°C. With such a configuration, condensation water can be efficiently removed during operation of the hydrogen generation device. [Industrial applicability]

[0087] The technology disclosed herein is useful for fuel cell systems, and in particular for systems using polymer electrolyte fuel cells. [Explanation of Symbols]

[0088] 10 Air supply unit 11 Branching point 12. First branch channel 13 Flow rate adjustment section 14. Second branch channel 14a Third branch channel 14b Fourth branch channel (inlet channel) 14c Fifth branch channel (air bleed channel) 14c1 upstream part 14c2 downstream part 14cf Folded section 14cm Lowest point of the 5th branch channel 14c 14m Lowest point of the inner surface of the 5th branch channel 14c 14p Opening of the fifth branch channel 14c at the branch section 17 14q Opening of the fifth branch channel 14c at the confluence 41 15 Flow meter 17 Branching point 17i Intersection of the fifth branch channel 14c with the central axis Ax17 at the branch section 17 18 Flow rate adjustment section 18m Flow rate adjustment section 18 central axis Ax18 lowest point 19 Storage section 19a,19b,19c container 19m Lowest point of storage section 19 20 Airflow channels 21 Common channel 30 Hydrogen generator 30s bottom side 31 Reformer 32 CO reducers 33 CO remover 34 Relay Channel 35 Container 36. Insulation material 37. Confluence 40 Anode gas flow path 40m Lowest point of the inner circumferential surface of the anode gas flow path 40 41 Confluence 41i Intersection of the central axis Ax41 of the fifth branch channel 14c at the confluence 41 50 Fuel Cell 51 Cathode 52 Anodes 100, 102, 104 Fuel cell systems H17 Height of branch section 17 H18 Height of flow rate adjustment section 18 H19 Height of storage section 19 H41 Height of the junction 41 D: Distance between the lowest point (14m) and the lowest point (40m) Ax Hydrogen Generator 30 Central Axis Ax17 Central axis of the fifth branch channel 14c in branch section 17 Ax18 Central axis of the flow rate adjustment section 18 Ax41 Central axis of the fifth branch channel 14c at the confluence 41 Ax40 Central axis of the anode gas flow path 40 G1 Air G2 mixed gas G3 Hydrogen-containing gas W Condensation water

Claims

1. Air supply unit, A hydrogen generator that produces hydrogen-containing gas, A solid polymer fuel cell that generates electricity from the hydrogen-containing gas, An air channel including multiple branching channels that guides air from the air supply to the hydrogen generator and the polymer electrolyte fuel cell, A flow rate adjustment unit is provided in the aforementioned branch channel and is positioned to receive heat from the outer surface of the hydrogen generation device, A storage unit is provided in the branch channel downstream of the flow rate adjustment unit and is arranged to receive heat from the outer surface of the hydrogen generator, Equipped with, A fuel cell system in which, in the vertical direction, the storage section is located below the flow rate adjustment section.

2. The plurality of branched channels include a first branched channel that guides the air to the cathode of the polymer electrolyte fuel cell and a second branched channel that guides the air to the hydrogen generator. The second branch channel is provided with the flow rate adjustment section and the storage section. The fuel cell system according to claim 1.

3. The second branch channel includes a third branch channel and an air bleed channel that branches off from the branch in the third branch channel and guides the air to the anode of the polymer electrolyte fuel cell. The air bleed passage is provided with the flow rate adjustment section and the storage section. The fuel cell system according to claim 2.

4. In the vertical direction, the reservoir is located at the lowest part of the air bleed passage. The fuel cell system according to claim 3.

5. In the vertical direction, the flow rate adjustment section is located below the branching section. The fuel cell system according to claim 3.

6. The device further comprises an anode gas channel for guiding the hydrogen-containing gas from the hydrogen generator to the anode of the polymer electrolyte fuel cell. The air bleed channel merges with the anode gas channel at the confluence point. In the vertical direction, the storage section is located below the confluence section. The fuel cell system according to claim 3.

7. In the vertical direction, the lowest point of the inner surface of the air bleed channel at the confluence is located above the lowest point of the inner surface of the anode gas channel at the confluence. The fuel cell system according to claim 6.

8. The hydrogen generation apparatus includes a CO reducer that reduces the concentration of carbon monoxide in the hydrogen-containing gas by a denaturation reaction, a CO remover that further reduces the concentration of carbon monoxide in the hydrogen-containing gas by a selective oxidation reaction, and a relay channel that guides the hydrogen-containing gas from the CO reducer to the CO remover. The second branch channel includes a third branch channel and an introduction channel that branches off from the branching portion in the third branch channel and guides the air to the relay channel. The introduction channel is provided with the flow rate adjustment section and the storage section. The fuel cell system according to claim 2.

9. The device further comprises an insulating member that integrally covers the flow rate adjustment unit, the storage unit, and the hydrogen generation device. The fuel cell system according to claim 1.

10. The hydrogen generating device includes a metal container. The aforementioned outer surface is the outer surface of the container, The flow rate adjustment unit and the storage unit are in contact with the outer surface of the container. The fuel cell system according to claim 1.

11. During operation of the hydrogen generation apparatus, the internal temperature of the flow rate adjustment section is in the range of 150°C to 200°C, and the internal temperature of the storage section is in the range of 220°C to 270°C. The fuel cell system according to claim 1.

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