Fuel cell stack assembly

Abstract

To provide a fuel cell stack assembly that can accommodate a filter member in a supply flow path while reducing the size of the fuel cell stack assembly.SOLUTION: A fuel cell stack assembly 10 includes a fuel cell stack 22 that generates electricity by being supplied with anode gas and cathode gas, a supply flow path 34 that supplies cathode gas to the fuel cell stack 22, a flow rate control valve provided in the supply flow path 34, and a convex filter member 90 that is arranged upstream of the flow rate control valve in the supply flow path 34 in the flow direction of the cathode gas. The flow rate control valve is a butterfly valve 40 having a plate-shaped valve body 40b. In the rotation direction of the valve body 40b, when a range through which the valve body can pass is defined as a first range R1 and a range through which the valve body 40b does not pass is defined as a second range R2, a tip 92 of the filter member 90 does not overlap the first range R1 and overlaps the second range R2.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a fuel cell stack assembly.

Background Art

[0002] Patent Document 1 describes a fuel cell system. The above fuel cell system includes a fuel cell stack, a supply flow path, and a flow rate adjustment valve provided in the supply flow path. The fuel cell stack generates electricity by supplying an anode gas and a cathode gas. The supply flow path supplies the cathode gas to the fuel cell stack. When the flow rate adjustment valve is opened, the cathode electrode of the fuel cell stack is opened from the supply flow path. When the flow rate adjustment valve is closed, the cathode electrode of the fuel cell stack is sealed from the supply flow path.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to prevent foreign matter from entering the fuel cell stack, a filter member may be arranged upstream of the flow rate adjustment valve in the supply flow path. In this case, in order to reduce the pressure loss due to the filter member, the filter member is formed in a convex shape, for example, a weight-like shape, so as to extend in the flow direction of the cathode gas.

[0005] By the way, in a fuel cell stack assembly in which a fuel cell stack, a supply flow path, a flow rate adjustment valve, and a filter member are assembled, there is a desire to miniaturize the fuel cell stack assembly by shortening the supply flow path. On the other hand, if the supply flow path is simply shortened, there is a risk that the convex filter member cannot be accommodated.

Means for Solving the Problems

[0006] A fuel cell stack assembly that solves the above problems includes a fuel cell stack that generates electricity when anode gas and cathode gas are supplied to it, a supply channel for supplying the cathode gas to the fuel cell stack, a flow control valve provided in the supply channel, and a convex-shaped filter member positioned upstream of the flow control valve in the supply channel in the direction of the flow of the cathode gas, wherein the flow control valve is a butterfly valve having a plate-shaped valve body, and in the rotational direction of the valve body, the range through which the valve body can pass is defined as a first range and the range through which the valve body cannot pass is defined as a second range, the tip of the filter member does not overlap with the first range but overlaps with the second range.

[0007] According to the above configuration, the filter member is positioned in the supply channel such that its tip does not overlap with the first range, and its tip overlaps with the second range. Therefore, the excess space in the supply channel that the valve body does not pass through can be used as a space to accommodate a portion of the filter member. Thus, the supply channel can be shortened while maintaining the space for accommodating the filter member. Consequently, the fuel cell stack assembly can be miniaturized while accommodating the filter member in the supply channel.

[0008] In the fuel cell stack assembly described above, the first range may include the position of the mechanical rotation limit of the valve body. With the above configuration, the tip of the filter member will not come into contact with the valve body of the butterfly valve.

[0009] In the fuel cell stack assembly described above, the filter member is weight-shaped, and the supply channel includes a first pipe housing the filter member and a second pipe housing the butterfly valve and connected to the first pipe, wherein the axis of the filter member and the axis of the second pipe are offset and parallel.

[0010] With the above configuration, the cathode gas that has passed through the filter component of the first pipe can flow more smoothly toward the second pipe. [Effects of the Invention]

[0011] According to this invention, the fuel cell stack assembly can be miniaturized while housing the filter member in the supply channel. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram illustrating a fuel cell system. [Figure 2] This is a cross-sectional view showing a fuel cell stack assembly. [Modes for carrying out the invention]

[0013] The following describes an embodiment of the fuel cell stack assembly with reference to Figures 1 and 2. Note that the fuel cell stack assembly is part of the fuel cell system. For convenience of explanation, the configuration of the fuel cell system will be described below.

[0014] <Fuel cell system> As shown in Figure 1, the fuel cell system 20 comprises a fuel cell stack 22, a cathode system 30, an anode system 60, a diluent 69, and a control unit 80.

[0015] The fuel cell stack 22 is a stack of multiple fuel cell cells 22a. The fuel cell cells 22a are, for example, solid molecular fuel cells. The multiple fuel cell cells 22a are housed in a casing 21. The fuel cell stack 22 generates electricity when anode gas and cathode gas are supplied. Each fuel cell 22a has an anode electrode to which anode gas is supplied, a cathode electrode to which cathode gas is supplied, and an electrolyte membrane placed between the anode electrode and the cathode electrode. The fuel cell cells 22a are sandwiched between separators.

[0016] The cathode system 30 includes a cathode flow path 30a. The cathode flow path 30a includes a cathode internal flow path 23 located inside the housing 21. A cathode gas flows through the cathode internal flow path 23. A part of the cathode internal flow path 23 is provided, for example, on a separator facing the cathode electrode in each fuel cell 22a.

[0017] A supply port 24 is formed in the housing 21. The cathode gas is supplied from the supply port 24 to the cathode internal flow path 23. A discharge port 25 is formed in the housing 21. The cathode gas is discharged from the discharge port 25 to the outside of the cathode internal flow path 23.

[0018] The anode system 60 includes an anode flow path 60a. The anode flow path 60a includes an anode internal flow path 26 located inside the housing 21. An anode gas flows through the anode internal flow path 26. The anode internal flow path 26 is provided, for example, on a separator facing the anode electrode in each fuel cell 22a.

[0019] An anode supply port 27 is formed in the housing 21. The anode gas is supplied from the anode supply port 27 to the anode internal flow path 26. An anode discharge port 28 is formed in the housing 21. The anode gas is discharged from the anode discharge port 28 to the outside of the anode internal flow path 26.

[0020] The fuel cell stack 22 generates electricity by the reaction between the anode gas flowing through the anode internal flow path 26 and the cathode gas flowing through the cathode internal flow path 23. The fuel cell stack 22 generates electricity by the reaction between the anode gas supplied to the anode flow path 60a and the cathode gas supplied to the cathode flow path 30a. Note that the cathode gas is an oxidant gas. Examples of the oxidant gas include oxygen in the air. The anode gas is a fuel gas. Examples of the fuel gas include hydrogen gas.

[0021] The anode system 60 includes a tank 61, an anode gas supply unit 62, a gas-liquid separator 65, a circulation pump 66, and an anode drain valve 67. The anode flow path 60a includes a supply path 63 and a circulation path 64.

[0022] The tank 61 stores anode gas. Anode gas is supplied from the tank 61 to the anode gas supply unit 62. The anode gas supply unit 62 is a component for adjusting the amount of anode gas supplied to the fuel cell stack 22. The amount of anode gas supplied to the fuel cell stack 22 can be adjusted by controlling the anode gas supply unit 62. As the anode gas supply unit 62, for example, a solenoid valve such as an injector can be used.

[0023] The supply path 63 connects the anode gas supply unit 62 and the anode supply port 27. The anode gas injected from the anode gas supply unit 62 is supplied to the fuel cell stack 22 through the supply path 63.

[0024] The circulation path 64 connects the anode discharge port 28 and the supply path 63. Anode exhaust gas flows through the circulation path 64. The anode exhaust gas includes unreacted anode gas and generated water generated by power generation in the fuel cell stack 22. The circulation path 64 is a passage for returning the unreacted anode gas contained in the anode exhaust gas to the supply path 63.

[0025] The gas-liquid separator 65 is provided in the circulation path 64. The gas-liquid separator 65 separates the anode exhaust gas into anode gas and generated water. The generated water separated from the anode exhaust gas is stored in the gas-liquid separator 65.

[0026] The circulation pump 66 is provided in the circulation path 64. The circulation pump 66 supplies the anode gas separated from the anode exhaust gas by the gas-liquid separator 65 to the supply path 63. Thereby, the anode gas circulates.

[0027] The anode drain valve 67 is connected to the gas-liquid separator 65. The anode drain valve 67 can be switched between an open state and a closed state. When the anode drain valve 67 is open, the generated water is discharged from the gas-liquid separator 65. The anode drain valve 67 may be switched from the closed state to the open state when the amount of generated water stored in the gas-liquid separator 65 exceeds a threshold. The anode drain valve 67 may be switched from the closed state to the open state at predetermined time intervals.

[0028] The gas-liquid separator 65 is connected to the diluent 69. When the anode drain valve 67 is open, the generated water and anode exhaust gas stored in the gas-liquid separator 65 are supplied to the diluent 69. The diluent 69 receives anode exhaust gas discharged from the gas-liquid separator 65 and cathode exhaust gas discharged from the fuel cell stack 22. The diluent 69 dilutes the incoming anode exhaust gas with the cathode exhaust gas. The diluent 69 reduces the concentration of hydrogen gas in the anode exhaust gas. The diluent 69 discharges the exhaust gas with reduced hydrogen gas concentration into the gas discharge passage 70. The exhaust gas is then discharged from the gas discharge passage 70.

[0029] The cathode system 30 includes a cathode gas inlet 31, an electric compressor 32, an intercooler 33, a butterfly valve 40, and a pressure regulating valve 41. The cathode flow path 30a includes a supply flow path 34 and a discharge flow path 35.

[0030] The cathode gas inlet 31 is an inlet for drawing cathode gas into the fuel cell system 20. When oxygen from the air is used as the cathode gas, the cathode gas inlet 31 may be open to the atmosphere. The cathode gas inlet 31 may be connected to a gas cylinder for storing cathode gas.

[0031] The electric compressor 32 is driven by an electric motor. The electric compressor 32 adjusts the amount of cathode gas supplied to the fuel cell stack 22. Specifically, the electric compressor 32 compresses the cathode gas supplied from the cathode gas inlet 31 and supplies it to the fuel cell stack 22. The amount of cathode gas supplied to the fuel cell stack 22 can be adjusted by controlling the electric compressor 32. The cathode gas may be supplied to the electric compressor 32 from the cathode gas inlet 31 through an air cleaner (not shown). The cathode gas supplied from the electric compressor 32 to the fuel cell stack 22 flows through the cathode internal passage 23.

[0032] The intercooler 33 is supplied with cathode gas discharged from the electric compressor 32. The intercooler 33 cools the cathode gas supplied from the electric compressor 32. The cathode gas supplied to the fuel cell stack 22 is the cathode gas that has been cooled by the intercooler 33.

[0033] The supply channel 34 is the portion of the cathode channel 30a located upstream of the cathode internal channel 23 in the direction of cathode gas flow. The supply channel 34 connects the electric compressor 32 to the supply port 24 of the housing 21. The intercooler 33 is installed in the supply channel 34.

[0034] The butterfly valve 40 is a flow control valve installed in the supply passage 34. The butterfly valve 40 opens and closes the supply passage 34, for example. The butterfly valve 40 can be switched between an open state and a closed state. When the butterfly valve 40 is open, cathode gas is supplied to the cathode internal passage 23 via the supply passage 34. The supply passage 34 supplies cathode gas to the fuel cell stack 22. When the butterfly valve 40 is closed, the supply of cathode gas to the cathode internal passage 23 is cut off.

[0035] The discharge channel 35 is the channel through which cathode exhaust gas flows. The cathode exhaust gas is the cathode gas discharged from the fuel cell stack 22 and contains generated water. Generated water produced by power generation in the fuel cell stack 22 is discharged from the fuel cell stack 22 through the discharge channel 35. Cathode gas supplied to the fuel cell stack 22 is discharged from the fuel cell stack 22 through the discharge channel 35. The cathode exhaust gas is discharged from the discharge channel 35 to the diluent 69. The diluent 69 dilutes the anode exhaust gas supplied from the gas-liquid separator 65 with the cathode exhaust gas and discharges it into the atmosphere.

[0036] The pressure regulating valve 41 is located in the discharge passage 35. The pressure regulating valve 41 is a butterfly valve that opens and closes the discharge passage 35. The flow path upstream of the pressure regulating valve 41 in the discharge passage 35 is connected to the outlet 25 of the housing 21. The flow path downstream of the pressure regulating valve 41 in the discharge passage 35 is connected to the diluent 69.

[0037] <Department Head> The control unit 80 comprises a processor 81 and a storage unit 82. The storage unit 82 includes RAM (Random Access Memory) and ROM (Read Only Memory). The storage unit 82 stores program code or instructions configured to cause the processor 81 to execute processing. The storage unit 82, i.e., the computer-readable medium, includes any available medium that can be accessed by a general-purpose or dedicated computer. The control unit 80 may be composed of hardware circuits such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The control unit 80, which is a processing circuit, may include one or more processors 81 that operate according to a computer program, one or more hardware circuits such as an ASIC or FPGA, or a combination thereof.

[0038] The control unit 80 controls, for example, the output power [kW] of the fuel cell stack 22. The output power of the fuel cell stack 22 varies depending on the amount of cathode gas supplied to the fuel cell stack 22 and the amount of anode gas supplied to the fuel cell stack 22. The output power of the fuel cell stack 22 is the power generated by the fuel cell stack 22. The control unit 80 controls the amount of anode gas supplied to the fuel cell stack 22 by controlling the anode gas supply unit 62. The control unit 80 controls the amount of cathode gas supplied to the fuel cell stack 22 by controlling the electric compressor 32.

[0039] The control unit 80 controls the power generation of the fuel cell stack 22. The control unit 80 switches between a power generation state and a power generation stop state of the fuel cell stack 22. The power generation states include a low-load power generation state, a medium-load power generation state, and a high-load power generation state. By transitioning the power generation state of the fuel cell stack 22, the control unit 80 can change the power generated by the fuel cell stack 22 in steps.

[0040] The control unit 80 controls the opening degree of the butterfly valve 40 and the pressure regulating valve 41. The control unit 80 stops the supply of anode gas by sealing the anode internal flow path 26. Sealing of the anode internal flow path 26 is performed by keeping the anode drain valve 67 in a closed state. The control unit 80 stops the supply of cathode gas by sealing the cathode internal flow path 23. Sealing of the cathode internal flow path 23 is performed by keeping the butterfly valve 40 and the pressure regulating valve 41 in a closed state. When cathode gas is supplied to the fuel cell stack 22, the control unit 80 keeps the butterfly valve 40 in an open state and adjusts the opening degree of the pressure regulating valve 41.

[0041] <Fuel cell stack assembly> As shown in Figure 2, the fuel cell stack assembly 10 includes a fuel cell stack 22, a supply channel 34, a butterfly valve 40, and a convex-shaped filter member 90. The filter member 90 is positioned upstream of the butterfly valve 40 in the cathode gas flow direction in the supply channel 34. The filter member 90 is, for example, conical. The filter member 90 tapers as it moves downstream in the cathode gas flow direction. The convex shape indicates that the filter member 90 tapers as it moves downstream in the cathode gas flow direction.

[0042] A mesh 90a is provided on the conical outer surface of the filter member 90. The mesh 90a is a mesh-like structure. The cathode gas flowing through the supply channel 34 passes through the mesh 90a. If the cathode gas contains foreign matter, the mesh 90a captures the foreign matter. Therefore, the filter member 90 prevents foreign matter from entering the fuel cell stack 22.

[0043] The supply channel 34 is a pipe connected to the fuel cell stack 22. The supply channel 34 has a first pipe 36, a second pipe 37, a third pipe 38, and a fourth pipe 39. The supply channel 34 includes the first pipe 36 and the second pipe 37.

[0044] The first pipe 36 houses the filter member 90. In the direction in which the axis m1 of the filter member 90 extends, the length L1 of the first pipe 36 is longer than the length L2 of the filter member 90. The base end 91 of the filter member 90 is fixed to the first end 36a of the first pipe 36. The tip 92 of the filter member 90 protrudes from the second end 36b of the first pipe 36.

[0045] The second pipe 37 is connected to the second end 36b of the first pipe 36. The second pipe 37 is a pipe whose axis m2 extends in a straight line. The axis m2 of the second pipe 37 and the axis m1 of the filter member 90 are offset and parallel. The second pipe 37 houses the butterfly valve 40. The butterfly valve 40 has a sealing member 40a, a plate-shaped valve body 40b, and a rotating shaft 40c.

[0046] The sealing member 40a is provided on the second pipe 37. The sealing member 40a is made of, for example, rubber. The sealing member 40a is annular in shape. The sealing member 40a has a seating surface 40d. The seating surface 40d is the inner circumferential surface of the sealing member 40a.

[0047] The valve body 40b is installed in the second piping 37. The rotating shaft 40c is attached to the valve body 40b. As the rotating shaft 40c rotates, the valve body 40b rotates, adjusting the opening degree of the butterfly valve 40. When the butterfly valve 40 is fully closed, the valve body 40b is in close contact with the sealing member 40a. This seals the cathode internal flow path 23. The rotating shaft 40c rotates due to a drive device (not shown), causing the valve body 40b to rotate. The control unit 80 controls the drive device (not shown), making it possible to adjust the opening degree of the butterfly valve 40.

[0048] As shown by the dashed line in Figure 2, the opening degree of the butterfly valve 40 increases as the valve body 40b moves away from the seat surface 40d. Conversely, the opening degree of the butterfly valve 40 decreases as the valve body 40b moves closer to the seat surface 40d.

[0049] The position of the valve body 40b shown by the dashed line in Figure 2 indicates the mechanical rotation limit of the valve body 40b. The range in which the valve body 40b can pass between the fully closed state of the butterfly valve 40 and the fully open state of the butterfly valve 40 is defined as the first range R1. The first range R1 includes the mechanical rotation limit of the valve body 40b. The first range R1 is located within the second piping 37. Furthermore, the range in which the valve body 40b does not pass in the rotation direction of the valve body 40b is defined as the second range R2. The second range R2 is located within the second piping 37.

[0050] Here, the tip 92 of the filter member 90 is located inside the second pipe 37. In other words, the filter member 90 is positioned to straddle the boundary between the first pipe 36 and the second pipe 37. Also, the tip 92 of the filter member 90 does not overlap with the first range R1, but overlaps with the second range R2. The tip 92 of the filter member 90 faces the space S formed between the valve body 40b and the seat surface 40d when the butterfly valve 40 is in the open state. In other words, when the butterfly valve 40 is in the open state, the space S is located on the axis m1 of the filter member 90.

[0051] The third pipe 38 is connected to the first pipe 36. Specifically, the first end 36a of the first pipe 36 is fitted inside the third pipe 38. In other words, the first pipe 36 and the third pipe 38 overlap each other.

[0052] The fourth pipe 39 is located between the second pipe 37 and the supply port 24 of the housing 21. The axis of the fourth pipe 39 coincides with the axis m2 of the second pipe 37. [Operation of this embodiment] The operation of this embodiment will now be explained.

[0053] The filter member 90 is positioned in the supply channel 34 such that its tip 92 does not overlap with the first range R1, and its tip 92 overlaps with the second range R2. Therefore, the excess space in the supply channel 34 that the valve body 40b does not pass through can be used as space to accommodate a portion of the filter member 90. Specifically, a portion of the filter member 90 is accommodated in the space in the second pipe 37 that the valve body 40b does not pass through. This allows, for example, the length L1 of the first pipe 36 to be shorter than the length L2 of the filter member 90. Thus, the supply channel 34 is shortened while maintaining the space for accommodating the filter member 90.

[0054] [Effects of this embodiment] The effects of this embodiment will now be explained. (1) The filter member 90 is positioned in the supply channel 34 such that its tip 92 does not overlap with the first range R1, and its tip 92 overlaps with the second range R2. Therefore, the excess space in the supply channel 34 that the valve body 40b does not pass through can be used as space to accommodate a part of the filter member 90. Thus, the supply channel 34 can be shortened while maintaining the space for accommodating the filter member 90. Consequently, the fuel cell stack assembly 10 can be miniaturized while accommodating the filter member 90 in the supply channel 34.

[0055] (2) The first range R1 includes the position of the mechanical rotation limit of the valve body 40b. This ensures that the tip 92 of the filter member 90 does not come into contact with the valve body 40b of the butterfly valve 40.

[0056] (3) The axis m1 of the filter member 90 and the axis m2 of the second pipe 37 are offset and parallel. Therefore, the cathode gas that has passed through the filter member 90 of the first pipe 36 flows smoothly toward the second pipe 37.

[0057] (4) The first pipe 36 and the third pipe 38 overlap each other. Therefore, the supply channel 34 can be shortened to a suitable length. [Example of changes] This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0058] ○ The supply channel 34 has a first pipe 36, a second pipe 37, and a third pipe 38, and the fourth pipe 39 may be omitted. In this case, the second pipe 37 is connected to the supply port 24 of the housing 21. By making this change, the supply channel 34 can be made even shorter.

[0059] ○ The axis m1 of the filter member 90 and the axis m2 of the second pipe 37 do not need to be offset. For example, the axis m1 of the filter member 90 and the axis m2 of the second pipe 37 may coincide. However, the tip 92 of the filter member 90 should not overlap with the first range R1.

[0060] ○ The axis m1 of the filter member 90 and the axis m2 of the second pipe 37 do not have to be parallel. The axis m1 of the filter member 90 and the axis m2 of the second pipe 37 do intersect. ○ The first range R1 does not necessarily include the position of the mechanical rotation limit of the valve body 40b. For example, the position of the valve body 40b where the butterfly valve 40 is fully open may be a position closer to the seat surface 40d in the opposite direction of rotation than the position of the mechanical rotation limit of the valve body 40b.

[0061] ○ The filter member 90 was cone-shaped, but it may also be hemispherical, for example. In short, the filter member 90 may be modified as appropriate, as long as it has a convex shape that tapers towards the downstream direction in the flow direction of the cathode gas. [Explanation of Symbols]

[0062] 10...Fuel cell stack assembly, 22...Fuel cell stack, 34...Supply channel, 36...First piping, 37...Second piping, 40...Butterfly valve as flow control valve, 40b...Valve body, 90...Filter member, 92...Tip of filter member, R1...First range, R2...Second range, m1...Axis of filter member, m2...Axis of second piping.

Claims

1. A fuel cell stack that generates electricity when anode gas and cathode gas are supplied, A supply channel for supplying the cathode gas to the fuel cell stack, A flow control valve provided in the supply channel, A fuel cell stack assembly comprising a convex-shaped filter member positioned upstream of the flow control valve in the supply channel in the direction of cathode gas flow, The flow control valve is a butterfly valve having a plate-shaped valve body. In the rotational direction of the valve body, if the range through which the valve body can pass is defined as a first range and the range through which the valve body cannot pass is defined as a second range, the tip of the filter member is characterized in that it does not overlap with the first range and overlaps with the second range.

2. The fuel cell stack assembly according to claim 1, wherein the first range includes the position of the mechanical rotation limit of the valve body.

3. The filter member is weight-shaped, The aforementioned supply channel is The first piping housing the filter member, It includes a second pipe that houses the butterfly valve and is connected to the first pipe, The fuel cell stack assembly according to claim 1 or claim 2, wherein the axis of the filter member and the axis of the second pipe are offset and parallel.

Images