Fuel cell module, and power generation system

Abstract

To provide a fuel cell module capable of replacing a gas in the fuel cell module based on various kinds of control, and a power generation system.SOLUTION: A fuel cell module 10 comprises: a supply path 63 for supplying a hydrogen gas or a nitrogen gas to a fuel cell stack 21; a circulation path 64 for circulating the hydrogen gas, which is exhausted from the fuel cell stack 21, to the supply path 63; an exhaust / drain valve 67 which exhausts the hydrogen gas from the circulation path 64; and a control device 100 which controls an injector 61 and the exhaust / drain valve 67 based on an instruction of a main control apparatus 90. The control device 100 performs exhaust processing for exhausting the hydrogen gas or nitrogen gas being present in the fuel cell stack 21, the supply path 63 and the circulation path 64 and then performs filling processing for filling them with the nitrogen gas based on a replacement command from the main control apparatus 90.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fuel cell module and a power generation system. [Background technology]

[0002] BACKGROUND ART Conventionally, a technique is known for replacing hydrogen gas in a fuel cell power generation apparatus with nitrogen gas by filling the fuel cell power generation apparatus with an inert gas such as nitrogen gas during a power outage or the like (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 2928583 Summary of the Invention [Problem to be solved by the invention]

[0004] Recently, power generation systems have become known that include a fuel cell module and use the electricity generated by the fuel cell module for other components. In such power generation systems, it is preferable that the fuel cell module be able to fill the inert gas based on the control of the other components. However, the technology described in Patent Document 1, even though it has a component for filling the inert gas, is unable to fill the inert gas based on various controls. [Means for solving the problem]

[0005] A fuel cell module that achieves the above object includes a fuel cell stack that generates electricity by a reaction between an anode gas supplied to an anode flow path and a cathode gas supplied to a cathode flow path; an injector that is connected at one end to a hydrogen gas supply unit and an inert gas supply unit and that injects the anode gas or the inert gas; a supply path that is connected at one end to the injector and at the other end to the fuel cell stack and that supplies the anode gas or the inert gas to the fuel cell stack; a circulation path that circulates hydrogen gas discharged from the fuel cell stack to the supply path; The fuel cell stack is characterized in that it comprises an exhaust / drain valve that exhausts the anode gas from the circulation path, and a control unit that controls the injector and the exhaust / drain valve based on instructions from a main control unit that controls the supply of the anode gas and the inert gas, and the control unit performs an exhaust process to exhaust the anode gas or the inert gas present in the fuel cell stack, the supply path, and the circulation path based on a replacement command from the main control unit, and then performs a filling process to fill the fuel cell stack, the supply path, and the circulation path with the hydrogen gas or the inert gas.

[0006] According to this configuration, the gas inside the fuel cell module can be replaced based on various controls. In a fuel cell module that achieves the above-mentioned objective, the control unit may update an exhaust completion flag indicating that the exhaust process has been completed when the exhaust process has been completed, and may update a filling completion flag indicating that the filling process has been completed when the filling process has been completed.

[0007] This configuration allows the control unit and the main control device to cooperate more easily. In the fuel cell module that achieves the above object, the control unit may repeat the exhaust process and the filling process a predetermined number of times in the filling process related to the replacement process.

[0008] With this configuration, the gas inside the fuel cell module can be replaced with greater precision. In a fuel cell module that achieves the above-mentioned objective, the control unit may, when the fuel cell module is stopped, perform the exhaust process of exhausting the hydrogen gas while also performing the filling process of filling the inert gas, and when the fuel cell module is started, perform the exhaust process of exhausting the inert gas while also performing the filling process of filling the hydrogen gas.

[0009] With this configuration, it is possible to fill the fuel cell module with an appropriate gas depending on the state of the fuel cell module. The present invention is characterized in that the present invention is provided with any one of fuel cell modules that achieve the above-mentioned object, and the main control device, when the filling process of filling the hydrogen gas is executed in the fuel cell module, keeps the hydrogen gas supply valve in an open state upon completion of the filling process, and when the filling process of filling the inert gas is executed in the fuel cell module, controls the inert gas supply valve to a closed state upon completion of the filling process.

[0010] This configuration simplifies the process when starting up the fuel cell module. [Effects of the Invention]

[0011] According to the present invention, the gas inside the fuel cell module can be replaced based on various controls. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram used to explain a power generation system. [Figure 2] FIG. 2 is a flowchart used to explain the replacement request process executed by the control device. [Figure 3] FIG. 3 is a flowchart used to explain the replacement process executed by the control device. [Figure 4] FIG. 4 is a flowchart used to explain the replacement process executed by the main control device. [Figure 5] FIG. 5 is a flowchart used to explain the replacement process executed by the main control device. DETAILED DESCRIPTION OF THE INVENTION

[0013] <Embodiment> DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of a fuel cell module and a power generation system according to the present invention will be described with reference to the drawings.

[0014] [About Power Generation System 1] 1, the power generation system 1 includes, for example, a fuel cell module 10, a main control device 90, a hydrogen tank 91, an inert gas tank 92, a main stop valve 93, a main stop valve 94, and a supply line 95. The power generation system 1 is, for example, a stationary system.

[0015] The main control device 90 controls, for example, the fuel cell module 10 and various components (not shown) of the power generation system 1. The main control device 90 includes a hardware processor such as a CPU (Central Processing Unit) and is realized by the execution of a program (software). Some or all of these components may be realized by hardware (including circuitry) such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a GPU (Graphics Processing Unit), or may be realized by a combination of software and hardware. The program may be stored in advance in a storage device (not shown) equipped in the main control device 90 that includes a non-transitory storage medium such as an HDD (Hard Disk Drive), flash memory, EEPROM (Electrically Erasable Programmable Read Only Memory), ROM (Read Only Memory), or RAM (Random Access Memory). The main control device 90 and the fuel cell module 10 are connected to each other so as to be able to send and receive information.

[0016] The hydrogen tank 91 stores hydrogen gas. The inert gas tank 92 stores nitrogen gas. A supply path 95 connects the hydrogen tank 91 and the inert gas tank 92 to the fuel cell module 10. A main stop valve 93 and a main stop valve 94 are provided in the supply path 95. The main stop valves 93 and 94 are, for example, electromagnetic on-off valves. The main control device 90 controls the open / close states of the main stop valves 93 and 94. When the main stop valve 93 is controlled to an open state, hydrogen gas flows to the fuel cell module 10 via the supply path 95. When the main stop valve 94 is controlled to an open state, nitrogen gas flows to the fuel cell module 10 via the supply path 95. The main stop valve 93 is an example of a supply valve for hydrogen gas. The main stop valve 94 is an example of a supply valve for nitrogen gas.

[0017] [About the fuel cell module 10] The fuel cell module 10 includes, for example, a fuel cell system 20 and a control device 100. The fuel cell system 20 includes a fuel cell stack 21, a cathode system 30, an anode system 60, and a diluter 69.

[0018] The fuel cell stack 21 is, for example, a polymer electrolyte fuel cell. The fuel cell stack 21 includes a plurality of fuel cell units 22. Each fuel cell unit 22 includes an anode electrode to which an anode gas is supplied, a cathode electrode to which a cathode gas is supplied, and an electrolyte membrane disposed between the anode electrode and the cathode electrode. The fuel cell units 22 are sandwiched between separators.

[0019] The fuel cell stack 21 includes a cathode flow path 23 and an anode flow path 26. The cathode flow path 23 is provided, for example, in a separator facing the cathode electrode. A cathode gas flows through the cathode flow path 23. The cathode gas is, for example, an oxidant gas. In this example, the oxidant gas is oxygen in the air. An anode gas flows through the anode flow path 26. The anode gas is, for example, a fuel gas. In this example, the fuel gas is hydrogen gas. The anode flow path 26 is provided, for example, in a separator facing the anode electrode.

[0020] The cathode flow channel 23 has an inlet 24 and an outlet 25. Cathode gas flows into the cathode flow channel 23 from the inlet 24 and flows out from the outlet 25. The anode flow channel 26 has an inlet 27 and an outlet 28. Anode gas flows into the anode flow channel 26 from the inlet 27 and flows out from the outlet 28. The fuel cell stack 21 generates electricity by a reaction between the anode gas supplied to the anode flow channel 26 and the cathode gas supplied to the cathode flow channel 23.

[0021] The cathode system 30 includes a cathode gas inlet 31 , an electric compressor 32 , an intercooler 33 , a cathode supply channel 34 , a cathode discharge channel 37 , a first shutoff valve 40 , and a second shutoff valve 41 .

[0022] The cathode gas inlet 31 is an inlet for drawing cathode gas into the fuel cell system 20. When oxygen in the air is used as the cathode gas, the cathode gas inlet 31 may be open to the atmosphere. Alternatively, the cathode gas inlet 31 may be connected to a gas cylinder that stores the cathode gas. Hereinafter, the cathode gas inlet 31 is assumed to be open to the atmosphere.

[0023] The electric compressor 32 is driven by an electric motor. The electric compressor 32 supplies cathode gas to the fuel cell stack 21. Specifically, the electric compressor 32 compresses the cathode gas supplied from the cathode gas inlet 31 and supplies the compressed cathode gas to the fuel cell stack 21 via the intercooler 33. The cathode gas supplied from the electric compressor 32 to the fuel cell stack 21 flows through the cathode flow path 23.

[0024] The intercooler 33 is supplied with the 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 21 is the cathode gas that has been cooled by the intercooler 33.

[0025] The cathode supply path 34 connects the electric compressor 32 and the cathode flow path 23. Specifically, the cathode supply path 34 connects the electric compressor 32 and the inlet 24 of the cathode flow path 23. The cathode supply path 34 includes a first supply path 35 and a second supply path 36. The first supply path 35 connects the electric compressor 32 and the intercooler 33. The second supply path 36 connects the intercooler 33 and the cathode flow path 23.

[0026] The cathode discharge channel 37 connects the cathode flow path 23 and the diluter 69. Specifically, the cathode discharge channel 37 connects the outlet 25 of the cathode flow path 23 and the diluter 69. The cathode discharge channel 37 is a passage through which the cathode exhaust gas flows. The cathode exhaust gas is cathode gas discharged from the fuel cell stack 21 and contains produced water. The produced water is water produced by power generation in the fuel cell stack 21.

[0027] The first sealing valve 40 is provided in the cathode supply passage 34. Specifically, the first sealing valve 40 is provided in the second supply passage 36, and more specifically, between the intercooler 33 and the cathode flow passage 23. Furthermore, the second sealing valve 41 is provided in the cathode discharge passage 37. The first sealing valve 40 and the second sealing valve 41 are, for example, normally closed butterfly valves that seal the cathode flow passage 23.

[0028] The anode system 60 includes an injector 61 , a relief valve 62 , a supply path 63 , a circulation path 64 , a gas-liquid separator 65 , a circulation pump 66 , an exhaust / drain valve 67 , and a pressure sensor 68 .

[0029] Hydrogen gas as an anode gas or nitrogen gas as an inert gas is supplied to the injector 61 via a supply path 95. The injector 61 is a member for adjusting the amount of anode gas or the amount of inert gas supplied to the fuel cell stack 21. The amount of anode gas or the amount of inert gas supplied to the fuel cell stack 21 can be adjusted by controlling the injector 61.

[0030] The relief valve 62 is provided in the supply path 63, and automatically discharges the gas to release the pressure when the hydrogen gas or nitrogen gas supplied by the injector 61 exceeds a predetermined pressure.

[0031] The supply path 63 connects the injector 61 and the anode flow path 26. Specifically, the supply path 63 connects the injector 61 and the inlet 27 of the anode flow path 26. The anode gas or inert gas injected from the injector 61 is supplied to the fuel cell stack 21 through the supply path 63.

[0032] The circulation path 64 connects the anode flow path 26 and the supply path 63. Specifically, the circulation path 64 connects the outlet 28 of the anode flow path 26 and the supply path 63. Anode exhaust gas flows through the circulation path 64. The anode exhaust gas contains unreacted anode gas and generated water. The circulation path 64 is a path for returning the unreacted anode gas contained in the anode exhaust gas to the supply path 63. Inert gas also flows through the circulation path 64. The circulation path 64 is a path for returning the inert gas to the supply path 63.

[0033] 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 produced water. The produced water separated from the anode exhaust gas is stored in the gas-liquid separator 65.

[0034] The circulation pump 66 is provided in the circulation path 64. The circulation pump 66 supplies the anode gas or the inert gas separated from the anode exhaust gas by the gas-liquid separator 65 to the supply path 63. This causes the anode gas or the inert gas to circulate.

[0035] The exhaust / drain valve 67 is connected to the gas-liquid separator 65. The exhaust / drain valve 67 can be switched between an open state and a closed state. When the exhaust / drain valve 67 is in the open state, the produced water is discharged from the gas-liquid separator 65. The exhaust / drain valve 67 is switched from the closed state to the open state when the amount of produced water stored in the gas-liquid separator 65 exceeds a threshold value.

[0036] The gas-liquid separator 65 is connected to a diluter 69. When the exhaust / drain valve 67 is opened, the produced water stored in the gas-liquid separator 65 and the anode exhaust gas or inert gas are supplied to the diluter 69. The diluter 69 dilutes the anode exhaust gas or inert gas with the cathode exhaust gas and discharges it into the atmosphere.

[0037] The pressure sensor 68 is provided in the supply path 63. The pressure sensor 68 detects the pressure in the supply path 63. The control device 100 controls various components of the fuel cell module 10. The control device 100 includes, for example, a hardware processor such as a CPU, and is realized by the execution of a program. Some or all of these components may be realized by hardware (including a circuit unit) such as an LSI, ASIC, FPGA, or GPU, or may be realized by a combination of software and hardware. The program may be stored in advance in a storage device (not shown) that includes a non-transitory storage medium such as an HDD, flash memory, EEPROM, ROM, or RAM that the control device 100 includes. The control device 100 and the main control device 90 are connected so that they can send and receive information. The control device 100 is an example of a "control unit."

[0038] [Outline of processing by the control device 100 and the main control device 90] When the fuel cell module 10 generates power, the main control device 90 controls the main stop valve 93 to an open state and the main stop valve 94 to a closed state, thereby supplying hydrogen gas from the hydrogen tank 91 to the supply path 95. The control device 100 supplies hydrogen gas as an anode gas to the fuel cell stack 21 from the injector 61 connected to the supply path 95. As a result, the control device 100 fills the fuel cell stack 21, the supply path 63, and the circulation path 64 with hydrogen gas. The control device 100 also controls the electric compressor 32 to fill the fuel cell stack 21 and the cathode system 30 with air. Specifically, based on instructions from the main control device 90, the control device 100 controls the injector 61 and the electric compressor 32 while also controlling the apertures of the first shut-off valve 40 and the second shut-off valve 41. As a result, the fuel cell stack 21 generates power. The fuel cell stack 21 is connected to, for example, a power converter and a load (not shown), and operates using the power generated by the fuel cell stack 21.

[0039] When power generation by the fuel cell module 10 is stopped, the main control device 90 closes the main stop valves 93 and 94, thereby stopping the supply of nitrogen gas from the hydrogen tank 91. The control device 100 performs an exhaust process to exhaust hydrogen gas from the fuel cell stack 21, the supply path 63, and the circulation path 64. Next, the main control device 90 opens the main stop valve 94 to supply nitrogen gas as an inert gas from the inert gas tank 92. The control device 100 supplies nitrogen gas to the fuel cell stack 21 from the injector 61 connected to the supply path 95. As a result, the control device 100 fills the fuel cell stack 21, the supply path 63, and the circulation path 64 with nitrogen gas.

[0040] When restarting the fuel cell module 10, the control device 100 performs an exhaust process to exhaust nitrogen gas from the fuel cell stack 21, the supply path 63, and the circulation path 64. The main control device 90 controls the main stop valve 93 to an open state and the main stop valve 94 to a closed state, thereby supplying hydrogen gas from the hydrogen tank 91 to the supply path 95. The control device 100 supplies hydrogen gas as an anode gas to the fuel cell stack 21 from the injector 61 connected to the supply path 95. In this way, the control device 100 fills the fuel cell stack 21, the supply path 63, and the circulation path 64 with hydrogen gas. In addition, the control device 100 controls the electric compressor 32 to fill the fuel cell stack 21 and the cathode system 30 with air. In this way, the fuel cell stack 21 generates electricity.

[0041] [Various information and flags] When executing the above-mentioned processing, the information used between the control device 100 and the main control device 90 includes a replacement request value, a replacement command value, a supply valve request value, a supply valve state value, a filling completion flag, and an exhaust completion flag.

[0042] The replacement request value is information used by the control device 100 to request the main control device 90 to control the replacement when replacing the gas filled in the fuel cell stack 21, the supply path 63, and the circulation path 64. In this example, the replacement request value takes three values, 0 to 2. The control device 100 updates / saves the replacement request value stored in its own memory according to various situations. The main control device 90 references the replacement request value by reading it out from the memory of the control device 100. The content of the request corresponding to each value of the replacement request value is as follows:

[0043] Replacement request value=0: No replacement request to the main control unit 90. Replacement requirement value = 1: Hydrogen gas is replaced with nitrogen gas. Replacement requirement = 2: Nitrogen gas is replaced with hydrogen gas.

[0044] The replacement command value is information used when the main control device 90 commands the control device 100 to replace the gas filled in the fuel cell stack 21, the supply path 63, and the circulation path 64. In this example, the replacement command value takes three values, 0 to 2. The main control device 90 transmits information indicating the replacement command value to the control device 100 according to various situations. The control device 100 executes control related to the replacement of the gas filled in the fuel cell stack 21, the supply path 63, and the circulation path 64 based on the received replacement command value. The content of the command corresponding to each value of the replacement command value is as follows: Note that the main control device 90 transmitting information indicating a replacement command value of 1 or information indicating a replacement command value of 2 to the control device 100 is an example of a "replacement command".

[0045] Replacement command value=0: No gas replacement command is issued to the control device 100. Replacement command value=1: Hydrogen gas is replaced with nitrogen gas. Replacement command value=2: Nitrogen gas is replaced with hydrogen gas.

[0046] The supply valve request value is information used to request the main control device 90 to change the open / close state of the main stop valve 93 or the main stop valve 94 depending on the gas being supplied when the control device 100 replaces the gas filled in the fuel cell stack 21, the supply path 63, and the circulation path 64. In this example, the supply valve request value takes three values ​​from 0 to 2. The control device 100 updates / saves the supply valve request value stored in its own memory depending on various situations. The main control device 90 references the supply valve request value by reading it out from the memory of the control device 100. The content of the request corresponding to each value of the supply valve request value is as follows:

[0047] Supply valve request value=0: The main stop valve 93 is opened, and the main stop valve 94 is closed. Supply valve request value=1: The main stop valve 93 is closed, and the main stop valve 94 is opened. Supply valve request value=2: The main stop valve 93 is closed, and the main stop valve 94 is closed.

[0048] The supply valve state value is information used to indicate the current state of the main stop valves 93 and 94, which are controlled to a closed or open state under the control of the main control device 90. In this example, the supply valve state value takes three values, 0 to 2. Each time the main control device 90 controls the state of the main stop valves 93 and 94, it updates and saves the supply valve state value stored in its own memory. The control device 100 references the supply valve state value by reading it out from the memory of the main control device 90. The content of the request corresponding to each value of the supply valve state value is as follows:

[0049] Supply valve state value=0: Main stop valve 93 is open and main stop valve 94 is closed. Supply valve state value=1: Main stop valve 93 is closed and main stop valve 94 is open. Supply valve state value=2: Both the main stop valve 93 and the main stop valve 94 are closed.

[0050] The filling completion flag is information indicating whether or not the filling of hydrogen gas or nitrogen gas into the fuel cell stack 21, the supply path 63, and the circulation path 64 has been completed as a result of the control device 100 executing the filling process. In this example, the filling completion flag takes two values: ON and OFF. The control device 100 updates / saves the filling completion flag stored in its own memory depending on various situations. The main control device 90 references the filling completion flag by reading it from the memory of the control device 100. The contents corresponding to each value of the filling completion flag are as follows:

[0051] Filling completion flag = ON: Refueling of the fuel cell stack 21, the supply path 63, and the circulation path 64 with hydrogen gas or nitrogen gas has been completed. Filling completion flag=OFF: The fuel cell stack 21, the supply path 63, and the circulation path 64 have not been completely filled with hydrogen gas or nitrogen gas.

[0052] The exhaust completion flag is information indicating whether or not the exhaust of hydrogen gas or nitrogen gas from the fuel cell stack 21, the supply path 63, and the circulation path 64 has been completed as a result of the control device 100 executing the exhaust process. In this example, the exhaust completion flag takes two values: ON and OFF. The control device 100 updates / saves the exhaust completion flag stored in its own memory unit according to various conditions. The main control device 90 references the exhaust completion flag by reading it from the memory unit of the control device 100. The contents corresponding to each value of the exhaust completion flag are as follows:

[0053] Exhaust completion flag=ON: Exhaust of hydrogen gas or nitrogen gas from the fuel cell stack 21, the supply path 63, and the circulation path 64 has been completed. Exhaust completion flag=OFF: The exhaust of hydrogen gas or nitrogen gas from the fuel cell stack 21, the supply path 63, and the circulation path 64 is not complete.

[0054] [Replacement request process executed by the control device 100] The replacement request process executed by the control device 100 will be described in detail below with reference to Fig. 2. The process of the flowchart shown in Fig. 2 is repeatedly executed at predetermined time intervals.

[0055] First, the control device 100 determines whether an abnormality has been detected in the fuel cell module 10 (step S100). An abnormality may be, for example, an overcurrent flowing through a power converter or a load connected to the fuel cell stack 21, a voltage generated by the fuel cell stack 21 being outside a predetermined range, or a temperature abnormality occurring in the fuel cell stack 21, the power converter, the load, or the like. The control device 100 acquires detection results from voltage sensors and current sensors (not shown) provided in the fuel cell stack 21, and temperature sensors (not shown) that detect the temperatures of the fuel cell stack 21, the power converter, the load, and the like, and determines whether an abnormality has been detected based on the detection results. If the control device 100 determines that an abnormality has been detected (step S100; YES), the control device 100 requests the main control device 90 to perform various controls related to the substitution of hydrogen gas with nitrogen gas when power generation by the fuel cell module 10 is stopped, and then updates and saves the substitution request value to 1 (step S102), and ends the series of processes.

[0056] If the control device 100 determines that no abnormality has been detected (step S100; NO), it determines whether the replacement request value is 1 and whether the fuel cell module 10 has just been started up (step S104). Here, when the replacement request value is 1 and the fuel cell module 10 has just been started up, the fuel cell stack 21, the supply path 63, and the circulation path 64 are filled with nitrogen gas, and power generation is not possible. Therefore, the control device 100 is required to replace the nitrogen gas filling the fuel cell stack 21, the supply path 63, and the circulation path 64 with hydrogen gas. If the control device 100 determines that the replacement request value is 1 and that the fuel cell module 10 has just been started up (step S104; YES), it updates and saves the replacement request value to 2 (step S106) in order to request the main control device 90 to perform various controls related to the replacement of nitrogen gas with hydrogen gas, and ends the series of processes.

[0057] If the replacement request value is 1 and it is not the timing when the fuel cell module 10 has been started up, the fuel cell module 10 is generating power and therefore replacement processing is not required. Therefore, if the control device 100 determines that the replacement request value is 1 and it is not the timing when the fuel cell module 10 has been started up (step S104; NO), it determines that there is no need to request replacement and updates / saves the replacement request value to 0 (step S108), ending the series of processes.

[0058] [Replacement process executed by the control device 100] The replacement process executed by the control device 100 will be described in detail below with reference to Fig. 3. The process of the flowchart shown in Fig. 3 is repeatedly executed at predetermined time intervals. The process of the flowchart shown in Fig. 2 and the process of the flowchart shown in Fig. 3 may be executed in parallel or sequentially. The control device 100 also executes processes related to power generation, power generation stop, and restart of the fuel cell module 10 separately from the process of the flowchart shown in Fig. 2 and the process of the flowchart shown in Fig. 3.

[0059] First, the control device 100 determines whether the filling completion flag is OFF (step S200). If the control device 100 determines that the filling completion flag is ON (step S200; NO), the control device 100 ends the series of processes because there is no need to perform subsequent processes such as exhaust processing and filling processing.

[0060] When the control device 100 determines that the filling completion flag is OFF (step S200; YES), it determines whether the most recent replacement command value received from the main control device 90 before the processing of step S202 in this series of processing is executed is a value other than 0 (step S202). When the replacement command value is 0 (step S202; NO), the control device 100 determines that the main control device 90 has not requested the control device 100 to replace the gas, and ends the series of processing.

[0061] If the replacement command value is 1 or 2 (step S202; YES), the control device 100 updates and saves the supply valve request value to 2 (step S204) in order to request the main control device 90 to close the main stop valves 93 and 94 in order to perform exhaust processing as preprocessing for the replacement processing. The control device 100 references the supply valve state value stored in the memory of the main control device 90 at the timing when the processing of step S206 in this series of processing is performed, and determines whether the supply valve state value is 2 (step S206). If the supply valve state value is not 2 (step S206; NO), the control device 100 ends the series of processing because either the main stop valve 93 or the main stop valve 94 is in the open state and exhaust processing cannot be performed. As the main control device 90 controls the main stop valves 93 and 94, the control device 100 repeatedly executes the processing from steps S200 to S206 by repeatedly executing the flowchart shown in Figure 3 at predetermined time intervals until the supply valve state value becomes 2.

[0062] If the supply valve state value is 2 (step S206; YES), the control device 100 executes exhaust processing (step S208). In the exhaust processing, the control device 100, for example, controls the exhaust / drain valve 67 to be open while operating the electric compressor 32 and the circulation pump 66. As a result, the hydrogen gas or nitrogen gas filling the fuel cell stack 21, the supply path 63, and the circulation path 64 is diluted into cathode exhaust gas in the diluter 69 and exhausted to the atmosphere. The control device 100 operates the electric compressor 32 and the circulation pump 66 until the pressure in the supply path 63 indicated by the pressure sensor 68 falls below a predetermined pressure. Furthermore, when the pressure in the supply path 63 indicated by the pressure sensor 68 falls below the predetermined pressure, the control device 100 stops the electric compressor 32 and the circulation pump 66 and controls the exhaust / drain valve 67 to be closed. Next, the control device 100 determines that the exhaust of hydrogen gas or nitrogen gas from the fuel cell stack 21, the supply path 63, and the circulation path 64 has been completed through the process of step S208, and updates / saves the exhaust completion flag to ON (step S210).

[0063] Next, the control device 100 refers to the supply valve state value stored in the memory of the main control device 90 at the timing when the process of step S212 in this series of processes is executed, and determines whether the supply valve state value is 1 (step S212). That is, the control device 100 determines whether the main stop valve 93 is in a closed state, the main stop valve 94 is in an open state, and a state in which nitrogen gas can be supplied from the inert gas tank 92. If the control device 100 determines that the supply valve state value is not 1 (step S212; NO), the control device 100 refers to the supply valve state value stored in the memory of the main control device 90 at the timing when the process of step S214 in this series of processes is executed, and determines whether the supply valve state value is 0 (step S214). That is, the control device 100 determines whether the main stop valve 93 is in an open state, the main stop valve 94 is in a closed state, and a state in which hydrogen gas can be supplied from the hydrogen tank 91.

[0064] If the control device 100 determines that the supply valve state value is not 0 (step S214; NO), it determines that the supply valve state value is 2 and that neither hydrogen gas nor nitrogen gas can be supplied, and proceeds to step S212. As the main control device 90 controls the main stop valves 93 and 94, the control device 100 repeatedly executes the processes of steps S212 to S214 and waits until the supply valve state value becomes a value other than 2.

[0065] When the control device 100 determines that the supply valve state value is 1 (step S212; YES), it executes a filling process to fill the fuel cell stack 21, the supply path 63, and the circulation path 64 with nitrogen gas (step S216). In the filling process, the control device 100 operates the injector 61 for a predetermined time, thereby filling the fuel cell stack 21, the supply path 63, and the circulation path 64 with nitrogen gas supplied via the supply path 95. Next, the control device 100 determines that the filling of the fuel cell stack 21, the supply path 63, and the circulation path 64 with nitrogen gas has been completed through the process of step S216, and sets the filling completion flag to ON, updates, and saves the flag (step S218). Next, the control device 100 sets the exhaust completion flag to OFF, updates, and saves the flag (step S220). Next, the control device 100 determines that the replacement process of replacing the hydrogen gas in the fuel cell stack 21, the supply path 63, and the circulation path 64 with nitrogen gas has been completed by the processing up to step S220, sets the replacement request value to 0 (step S222), and ends the series of processing.

[0066] If the control device 100 determines that the supply valve state value is not 0 (i.e., the supply valve state value is 2) (step S214; YES), it executes a filling process to fill the fuel cell stack 21, the supply path 63, and the circulation path 64 with hydrogen gas (step S224). In the filling process, the control device 100 operates the injector 61 for a predetermined time, thereby filling the fuel cell stack 21, the supply path 63, and the circulation path 64 with hydrogen gas supplied via the supply path 95. Next, the control device 100 determines that the filling of the fuel cell stack 21, the supply path 63, and the circulation path 64 with hydrogen gas has been completed through the processing of step S224, and sets the filling completion flag to ON, updates, and saves the flag (step S226). Next, the control device 100 sets the exhaust completion flag to OFF, updates, and saves the flag (step S228). Next, the control device 100 determines that the replacement process of replacing the nitrogen gas in the fuel cell stack 21, the supply path 63, and the circulation path 64 with hydrogen gas has been completed by the processing up to step S228, sets the replacement request value to 0 (step S230), and ends the series of processing.

[0067] [Replacement process executed by the main control unit 90] The replacement process executed by the main control device 90 will be described in detail below with reference to Figures 4 and 5. The process of the flowcharts shown in Figures 4 and 5 is repeatedly executed at predetermined time intervals. Furthermore, the main control device 90 executes processes for the control device 100 associated with the control of the fuel cell module 10 and processes for controlling other components of the power generation system 1 separately from the processes of the flowcharts shown in Figures 4 and 5.

[0068] First, the main control device 90 determines whether or not it is necessary to shut down the fuel cell module 10 (step S300). The main control device 90 determines that it is necessary to shut down the fuel cell module 10 when, for example, an abnormality is occurring in the operation of a component other than the fuel cell module 10 provided in the power generation system 1. If the main control device 90 determines that it is necessary to shut down the fuel cell module 10 (step S300; YES), the process proceeds to step S304.

[0069] If the main control device 90 determines that it is not necessary to stop the fuel cell module 10 (step S300; NO), it references the replacement request value stored in the memory of the control device 100 at the timing when the processing of step S302 in this series of processing is executed, and determines whether the replacement request value is 1 (step S302). In other words, the main control device 90 determines whether the control device 100 is requesting that the hydrogen gas filled in the fuel cell stack 21, supply path 63, and circulation path 64 be replaced with nitrogen gas. If the main control device 90 determines that the replacement request value is 1 (step S302; YES), it transmits information indicating a replacement command value of 1 to the control device 100 (step S304), and the processing proceeds to step S312.

[0070] If the main control device 90 determines that the replacement request value is not 1 (step S302; NO), it references the replacement request value stored in the memory of the control device 100 at the timing when the processing of step S306 in this series of processing is executed, and determines whether the replacement request value is 2 (step S306). In other words, the main control device 90 determines whether the control device 100 is requesting that the nitrogen gas filling the fuel cell stack 21, supply path 63, and circulation path 64 be replaced with hydrogen gas. If the main control device 90 determines that the replacement request value is 2 (step S306; YES), it transmits information indicating that the replacement command value is 2 to the control device 100 (step S308), and the processing proceeds to step S312.

[0071] If the main control unit 90 determines that the replacement request value is not 2 (i.e., the replacement request value is 0) (step S306; NO), it assumes that there is no request for replacement and transmits information indicating a replacement command value of 0 to the control unit 100 (step S310), thereby ending the series of processes.

[0072] The main control device 90 updates / saves the filling completion flag to OFF (step S312). The main control device 90 determines whether the supply valve state value is 2 (step S314). If the main control device 90 determines that the supply valve state value is not 2 (step S314; NO), the main control device 90 ends the series of processes. When the supply valve state value is not 2 at the timing when the process of step S314 is executed, this occurs when a replacement request is received from the control device 100 through the process shown in FIG. 2, but the control device 100 has not yet completed the process of step S204 shown in FIG. 3. When a replacement request is received from the control device 100 and until the process of step S204 is executed, the main control device 90 repeatedly executes the flowcharts shown in FIGS. 4 and 5 at predetermined time intervals, thereby repeatedly executing the processes of steps S300 to S314.

[0073] If the main control device 90 determines that the supply valve state value is 2 (step S314; YES), it controls both the main stop valves 93 and 94 to a closed state (step S316). Based on the processing of step S316, the main control device 90 updates and saves the supply valve state value to 2 (step S318). Next, the main control device 90 references the exhaust completion flag stored in the memory unit of the control device 100 at the timing when the processing of step S316 in this series of processing is executed, and determines whether the exhaust completion flag is ON or not (step S320). In other words, the main control device 90 determines whether the exhaust process in the control device 100 has been completed. If the main control device 90 determines that the exhaust completion flag is OFF (step S320; NO), it repeatedly executes the determination processing of step S320 and waits until the exhaust completion flag is set to ON.

[0074] When the main control device 90 determines that the exhaust completion flag is ON (step S320; YES), it references the replacement request value stored in the memory unit of the control device 100 at the timing when the processing of step S318 in this series of processing is executed, and determines whether the replacement request value is 1 (step S322). When the main control device 90 determines that the replacement request value is 1 (step S322; YES), it determines that the control device 100 is requesting the replacement of hydrogen gas with nitrogen gas, and controls the valve supplying nitrogen gas to an open state (step S324). Specifically, the main control device 90 controls the main stop valve 93 to a closed state and the main stop valve 94 to an open state. Based on the processing of step S324, the main control device 90 updates and saves the supply valve state value to 1 (step S326). If the main control device 90 determines that the replacement request value is not 1 (i.e., the replacement request value is 2) (step S322; NO), it determines that the control device 100 is requesting replacement of nitrogen gas with hydrogen gas, and controls the valve supplying hydrogen gas to an open state (step S328). Specifically, the main control device 90 controls the main stop valve 93 to an open state, while controlling the main stop valve 94 to a closed state. Based on the processing of step S328, the main control device 90 updates / saves the supply valve state value to 0 (step S330).

[0075] Next, the main control device 90 refers to the filling completion flag stored in the memory of the control device 100 at the timing when the processing of step S324 in this series of processing is executed, and determines whether the filling completion flag is ON or not (step S332). In other words, the main control device 90 determines whether the filling processing has been completed in the control device 100. If the main control device 90 determines that the filling completion flag is OFF (step S332; NO), it repeatedly executes the determination processing of step S332 and waits until the filling completion flag is set to ON.

[0076] When the main control device 90 determines that the filling completion flag is ON (step S332; YES), it determines whether the supply valve state value is 1 (step S326). When the main control device 90 determines that the supply valve state value is 1 (step S334; YES), since there is no opportunity to supply nitrogen gas again after the replacement of hydrogen gas with nitrogen gas is completed, the main control device 90 controls the valves that supply nitrogen gas to a closed state (step S336). Specifically, the main control device 90 controls both the main stop valves 93 and 94 to a closed state. Based on the processing of step S336, the main control device 90 updates and saves the supply valve state value to 2 (step S338). When the main control device 90 determines that the supply valve state value is not 1 (i.e., the supply valve state value is 0) (step S334; NO), the main control device 90 leaves the states of the main stop valves 93 and 94 unchanged, and proceeds to step S340. Main control device 90 updates and saves the replacement command value to 0 (step S340), and ends the series of processes.

[0077] [Effects of the embodiment] According to the above embodiment, the following effects can be obtained. (1) Based on a replacement command from the main control device 90, the control device 100 performs an exhaust process to exhaust the hydrogen gas or the inert gas present in the fuel cell module 10, the supply path 63, and the circulation path 64. After performing the exhaust process, the control device 100 also performs a filling process to fill the fuel cell module 10, the supply path 63, and the circulation path 64 with hydrogen gas or nitrogen gas as an inert gas.

[0078] As described above, the power generation system 1 is, for example, a stationary system. Meanwhile, the fuel cell module 10 provided in the power generation system 1 is a general-purpose module that is not limited to being installed in a stationary power generation system 1 but can also be installed in a mobile system. Here, in a mobile system, the fuel cell module 10 may remain filled with hydrogen gas when the fuel cell module 10 is stopped. Meanwhile, unlike a mobile system, in a stationary power generation system 1, it may be necessary to replace the hydrogen gas in the fuel cell module 10 with nitrogen gas when the fuel cell module 10 is stopped.

[0079] The control device 100 cannot control the main stop valves 93, 94 and cannot switch the supply of hydrogen gas and nitrogen gas by itself, so it is required to cooperate with the main control device 90 when replacing gases. Similarly, the main control device 90 cannot control the opening and closing of the electric compressor 32, the circulation pump 66, and the exhaust and drain valve 67, so it is required to cooperate with the control device 100 when replacing gases. With this configuration, the control device 100 and the main control device 90 cooperate to replace gases in the fuel cell module 10 based on various controls.

[0080] (2) When the exhaust process is completed, the control device 100 updates the exhaust completion flag indicating that the exhaust process is completed. Also, when the filling process is completed, the control device 100 updates the filling completion flag indicating that the filling process is completed.

[0081] According to this configuration, the control device 100 updates the exhaust completion flag upon completion of the exhaust process, allowing the main control device 90 to recognize the completion of the exhaust process. Also, the control device 100 updates the filling completion flag upon completion of the filling process, allowing the main control device 90 to recognize the completion of the filling process. Therefore, cooperation between the control device 100 and the main control device 90 can be facilitated.

[0082] (3) When the fuel cell module 10 is stopped, the control device 100 performs an exhaust process to exhaust hydrogen gas and a filling process to fill nitrogen gas as an inert gas. Furthermore, when the fuel cell module 10 is started, the control device 100 performs an exhaust process to exhaust nitrogen gas and a filling process to fill hydrogen gas. With this configuration, the control device 100 can fill the fuel cell module 10 with an appropriate gas depending on the state of the fuel cell module 10.

[0083] (4) When a filling process for filling hydrogen gas is performed in the fuel cell module 10, the control device 100 keeps the main stop valve 93 open upon completion of the filling process, while when a filling process for filling nitrogen gas is performed in the fuel cell module 10, the control device 100 controls the main stop valve 94 to a closed state upon completion of the filling process.

[0084] 5, in which nitrogen gas is replaced with hydrogen gas, the main stop valves 93, 94 are in an open state with the main stop valve 93 in an open state and the main stop valve 94 in a closed state. Here, when restarting the fuel cell module 10, in a state in which nitrogen gas has been replaced with hydrogen gas, it is necessary to supply hydrogen gas again after power generation has started. Therefore, if the open main stop valve 93 is closed after replacing nitrogen gas with hydrogen gas, it is necessary to open the main stop valve 93 again when hydrogen gas is to be supplied again, which is time-consuming. This configuration allows the main control device 90 to simplify the startup process of the fuel cell module 10.

[0085] 5, in which hydrogen gas is replaced with nitrogen gas, the main stop valve 93 is closed and the main stop valve 94 is open. Here, after the gas in the fuel cell module 10 has been replaced with nitrogen gas, there is no need to supply nitrogen gas again. Therefore, if the main stop valve 94 is left open after replacing nitrogen gas with hydrogen gas, it will be necessary to close the main stop valve 94 again when hydrogen gas is to be supplied to restart the fuel cell module 10, which is time-consuming. With this configuration, the main control device 90 can simplify the processing at the start-up of the fuel cell module 10.

[0086] The above-described embodiments may be modified as follows: The above-described embodiments and the following modifications may be combined with each other within the scope of technical compatibility. In the above description, in the hydrogen gas or nitrogen gas filling process, the control device 100 operates the injector 61 for a predetermined time to fill the fuel cell stack 21, the supply path 63, and the circulation path 64 with gas supplied via the supply path 95. However, this is not limited to this. In the filling process, the control device 100 may repeat the exhaust process and the filling process a predetermined number of times in this order. The predetermined number of times is based on, for example, the volumes of the fuel cell stack 21, the supply path 63, and the circulation path 64, and the amount of gas supplied by the injector 61 in one filling process. Specifically, the total amount of gas supplied by the injector 61 performing the filling process a predetermined number of times matches the volumes of the fuel cell stack 21, the supply path 63, and the circulation path 64. More specifically, the predetermined number of times is, for example, several times.

[0087] In this case, the main control unit 90 retains the number of times the exhaust process and the filling process have been repeated since the replacement command value became 1 or 2 in step S304 or step S306 in this series of processes. The main control unit 90 also executes a determination process between step S332 and step S334 to determine whether the exhaust process and the filling process have been repeated a predetermined number of times. If the main control unit 90 determines that the exhaust process and the filling process have been repeated a predetermined number of times, it proceeds to step S334. If the main control unit 90 determines that the exhaust process and the filling process have not been repeated a predetermined number of times, it proceeds to step S314. As a result, the replacement command value is not updated. Therefore, when the flowcharts of FIGS. 4 and 5 are executed again, the replacement command value becomes a value other than 0 in step S202, allowing the exhaust process and the filling process to be repeated again. The main control unit 90 also clears the retained number of times the exhaust process and the filling process have been repeated when the replacement command value is set to 0 in step S340.

[0088] Here, the gas can be replaced more accurately by filling the gas in several batches than by filling the gas all at once in an amount corresponding to the volume of the fuel cell stack 21, the supply path 63, and the circulation path 64. With this configuration, the control device 100 can replace the gas in the fuel cell module 10 more accurately.

[0089] The first shutoff valve 40 may be provided in the first supply passage 35 between the intercooler 33 and the electric compressor 32. The exhaust drain valve 67 may be switched from a closed state to an open state at predetermined time intervals.

[0090] Nitrogen gas is an example of an inert gas, but the inert gas is not limited to this, and instead of nitrogen gas, another inert gas may be stored in the inert gas tank 92. Examples of the inert gas include helium gas and argon gas.

[0091] The technical concepts that can be understood from the above-described embodiments and modifications will be described below. [Aspect 1] The fuel cell module includes a fuel cell stack that generates electricity by a reaction between an anode gas supplied to an anode flow path and a cathode gas supplied to a cathode flow path; an injector connected at one end to a hydrogen gas supply unit and an inert gas supply unit, for injecting the anode gas or the inert gas; a supply path having one end connected to the injector and the other end connected to the fuel cell stack, for supplying the anode gas or the inert gas to the fuel cell stack; a circulation path for circulating hydrogen gas discharged from the fuel cell stack to the supply path; an exhaust / drain valve for exhausting the anode gas from the circulation path; a control unit that controls the injector and the exhaust drain valve based on instructions from a main control unit that controls the supply of the anode gas and the inert gas, Based on a replacement command from the main control device, the control unit performs an exhaust process to exhaust the anode gas or the inert gas present in the fuel cell stack, the supply path, and the circulation path, and then performs a filling process to fill the fuel cell stack, the supply path, and the circulation path with the hydrogen gas or the inert gas.

[0092] [Aspect 2] The control unit of the fuel cell module described in [Aspect 1] updates an exhaust completion flag indicating that the exhaust process has been completed when the exhaust process has been completed, and updates a filling completion flag indicating that the filling process has been completed when the filling process has been completed.

[0093] [Aspect 3] A fuel cell module according to [Aspect 1] or [Aspect 2], wherein the control unit repeats the exhaust process and the filling process a predetermined number of times during the filling process related to the replacement command.

[0094] [Aspect 4] A fuel cell module described in any one of [Aspect 1] to [Aspect 3], wherein the control unit, when the fuel cell module is stopped, performs the exhaust process of exhausting the hydrogen gas while also performing the filling process of filling the inert gas, and when the fuel cell module is started, performs the exhaust process of exhausting the inert gas while also performing the filling process of filling the hydrogen gas.

[0095] [Aspect 5] A power generation system comprising a fuel cell module described in any one of [Aspect 1] to [Aspect 4], in which the main control device controls each part, wherein when the filling process of filling hydrogen gas is performed in the fuel cell module, the main control device keeps the hydrogen gas supply valve in an open state upon completion of the filling process, and when the filling process of filling inert gas is performed in the fuel cell module, the main control device controls the inert gas supply valve to a closed state upon completion of the filling process. [Explanation of symbols]

[0096] 1...power generation system, 10...fuel cell module, 20...fuel cell system, 21...fuel cell stack, 22...fuel cell, 23...cathode flow path, 24, 27...inlet, 25, 28...outlet, 26...anode flow path, 30...cathode system, 31...cathode gas intake port, 32...electric compressor, 33...intercooler, 34...cathode supply path, 35...first supply path, 36...second supply path, 3 7...cathode discharge path, 40...first sealing valve, 41...second sealing valve, 60...anode system, 61...injector, 62...relief valve, 63...supply path, 64...circulation path, 65...gas-liquid separator, 66...circulation pump, 67...exhaust drain valve, 68...pressure sensor, 69...diluter, 90...main control device, 91...hydrogen tank, 92...inert gas tank, 93, 94...main stop valve, 95...supply path, 100...control device.

Claims

1. a fuel cell stack that generates electricity by a reaction between an anode gas supplied to an anode flow channel and a cathode gas supplied to a cathode flow channel; an injector connected at one end to a hydrogen gas supply unit and an inert gas supply unit, for injecting the anode gas or the inert gas; a supply path having one end connected to the injector and the other end connected to the fuel cell stack, for supplying the anode gas or the inert gas to the fuel cell stack; a circulation path for circulating hydrogen gas discharged from the fuel cell stack to the supply path; an exhaust / drain valve for exhausting the anode gas from the circulation path; a control unit that controls the injector and the exhaust drain valve based on instructions from a main control unit that controls the supply of the anode gas and the inert gas, the control unit performs an exhaust process to exhaust the anode gas or the inert gas present in the fuel cell stack, the supply path, and the circulation path based on a replacement command from the main control device, and then performs a filling process to fill the fuel cell stack, the supply path, and the circulation path with the hydrogen gas or the inert gas. Fuel cell module.

2. When the exhaust process is completed, the control unit updates an exhaust completion flag indicating that the exhaust process is completed, and when the filling process is completed, updates a filling completion flag indicating that the filling process is completed. The fuel cell module according to claim 1 .

3. the control unit repeats the exhaust process and the filling process a predetermined number of times in the filling process related to the replacement command. The fuel cell module according to claim 1 .

4. the control unit, when the fuel cell module is stopped, performs the exhaust process of exhausting the hydrogen gas and the filling process of filling the inert gas, and when the fuel cell module is started, performs the exhaust process of exhausting the inert gas and the filling process of filling the hydrogen gas. The fuel cell module according to claim 1 .

5. A power generation system comprising the fuel cell module according to any one of claims 1 to 3, wherein the main control device controls each unit, When the filling process of filling the hydrogen gas is executed in the fuel cell module, the main control device keeps the hydrogen gas supply valve in an open state upon completion of the filling process, and when the filling process of filling the inert gas is executed in the fuel cell module, the main control device controls the inert gas supply valve to a closed state upon completion of the filling process. Power generation system.

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