Fuel cell module, and vehicle equipped with a fuel cell module

Abstract

To accurately make a determination as to whether an abnormality occurs in a circulation pump.SOLUTION: A control unit 80 performs abnormality determination processing of determining whether an abnormality occurs in a circulation pump 66 on the basis of first internal pressure that is the internal pressure of a supply channel 64a detected by an internal pressure sensor 42 in a first period, and second internal pressure that is the internal pressure of the supply channel 64a detected by the internal pressure sensor 42 in a second period. The first period is a period after the start of the drive of a fuel cell module 10, a period before the start of injection of fuel gas from an injector 62, and a period before the start of the drive of the circulation pump 66. The second period is a period after the first period, a period before the start of injection of fuel gas from the injector 62, and a period after the lapse of a predetermined period from the start of the drive of the circulation pump 66.SELECTED DRAWING: Figure 2

Description

Technical Field

[0004] , , ,

[0005] , , , ,

[0001] The present invention relates to a fuel cell module and a vehicle equipped with the fuel cell module.

Background Art

[0002] The fuel cell module described in Patent Document 1 includes a fuel cell stack that generates power using fuel gas, a supply flow path that supplies the fuel gas to the fuel cell stack, and a circulation flow path that circulates the fuel gas discharged from the fuel cell stack back to the supply flow path. Further, the fuel cell module includes an internal pressure sensor and a circulation pump provided in the circulation flow path. The internal pressure sensor detects the internal pressure of the circulation flow path. In the fuel cell module described in Patent Document 1, the change in the internal pressure of the circulation flow path is detected based on the detection value from the internal pressure sensor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There may be adopted an internal pressure sensor that detects the internal pressure of the supply flow path as the internal pressure sensor. In the fuel cell module provided with this internal pressure sensor, it has been desired to accurately determine whether an abnormality has occurred in the circulation pump based on the detection value of the internal pressure sensor.

Means for Solving the Problems

[0005] A fuel cell module that solves the above problems comprises a fuel cell stack that generates electricity using fuel gas, an injector that injects fuel gas, a supply channel that supplies the fuel gas injected from the injector to the fuel cell stack, a circulation channel that circulates the fuel gas discharged from the fuel cell stack back into the supply channel, an internal pressure sensor that detects the internal pressure of the supply channel, a circulation pump provided in the circulation channel, and a control device that controls the drive of the circulation pump, wherein the control device detects a first internal pressure, which is the internal pressure of the supply channel detected by the internal pressure sensor in the first period. The first period is the period after the start of operation of the fuel cell module, before the start of fuel gas injection from the injector, and before the start of operation of the circulation pump, and the second period is the period after the start of operation of the circulation pump, and is characterized in that an abnormality determination process is performed to determine whether or not an abnormality has occurred in the circulation pump, and the first period is the period after the start of operation of the fuel cell module, before the start of fuel gas injection from the injector, and after a predetermined period has elapsed since the start of operation of the circulation pump.

[0006] According to the above configuration, the control device performs an abnormality determination process to determine whether or not there is an abnormality in the circulation pump based on the first internal pressure and the second internal pressure. The first internal pressure is the internal pressure of the supply passage detected by the internal pressure sensor during the first period. The second internal pressure is the internal pressure of the supply passage detected by the internal pressure sensor during the second period. Both the first period in which the first internal pressure is detected and the second period in which the second internal pressure is detected are periods before the start of fuel gas injection from the injector. During the period before the start of fuel gas injection from the injector, there are no fluctuations in the internal pressure of the supply passage caused by fuel gas injection from the injector. Therefore, by performing the abnormality determination process based on the first internal pressure and the second internal pressure, the abnormality determination process can be performed based on fluctuations in the internal pressure of the supply passage under conditions where fluctuations in the internal pressure of the supply passage caused by factors other than the operation of the circulation pump are unlikely to occur. Furthermore, the first period in which the first internal pressure is detected is the period before the start of operation of the circulation pump. Therefore, the first internal pressure is the internal pressure of the supply channel when there is no fluctuation in the internal pressure of the supply channel caused by the operation of the circulation pump. The second period during which the second internal pressure is detected is the period after a predetermined period has elapsed since the start of operation of the circulation pump. Therefore, the second internal pressure is the internal pressure of the supply channel when fluctuations in the internal pressure of the supply channel caused by the operation of the circulation pump occur. In the abnormality determination process, the control device determines whether or not an abnormality has occurred in the circulation pump based on the first internal pressure and the second internal pressure, thereby determining whether or not an abnormality has occurred in the circulation pump based on the change in the internal pressure of the supply channel caused by the operation of the circulation pump. Thus, it is possible to determine whether or not an abnormality has occurred in the circulation pump with high accuracy.

[0007] In a fuel cell module, the control device may perform the abnormality determination process each time the fuel cell module is started to operate, and if the abnormality determination process determines that there is an abnormality in the circulation pump, it may count the number of determinations, and if the abnormality determination process determines that there is no abnormality in the circulation pump, it may reset the number of determinations, and if the number of determinations is two or more predetermined times, it may confirm that there is an abnormality in the circulation pump.

[0008] With the above configuration, the control device will not determine that there is an abnormality in the circulation pump until the number of determinations reaches a predetermined number. Therefore, if the abnormality determination process determines that there is an abnormality in the circulation pump due to factors other than the circulation pump itself, it is possible to prevent the device from determining that there is an abnormality in the circulation pump.

[0009] In a fuel cell module, the control device includes a storage unit that stores the average value of the first internal pressure detected multiple times from the internal pressure sensor during the first period as the average internal pressure. In the abnormality determination process, the device may repeatedly perform the following during the second period: obtaining the second internal pressure from the internal pressure sensor and determining whether the difference between the obtained second internal pressure and the average internal pressure stored in the storage unit is less than a predetermined value. The device may then determine that an abnormality has occurred in the circulation pump if the determination process determines that the difference is less than the predetermined value for a predetermined period of time.

[0010] According to the above configuration, the control device will not determine that there is an abnormality in the circulation pump unless it continuously determines that the difference is below a predetermined value for a predetermined period of time during the judgment process. Therefore, it is possible to suppress the determination that there is an abnormality in the circulation pump when the difference temporarily falls below a predetermined value due to factors other than an abnormality in the circulation pump during the abnormality determination process.

[0011] A vehicle equipped with a fuel cell module that solves the above problems is a vehicle equipped with the fuel cell module described above, wherein the vehicle is equipped with a vehicle load that is driven by power supplied from the fuel cell module, the control device performs the abnormality determination process on the condition that the fuel cell module starts to drive, and the first period may include the period from the start of operation of the fuel cell module until the contactor connecting the fuel cell stack and the vehicle load turns ON.

[0012] With the above configuration, the control device can acquire the first internal pressure used for abnormality detection processing during the period from the start of operation of the fuel cell module until the contactor turns on. Therefore, the period from the start of operation of the fuel cell module until the contactor turns on can be used as a period for determining whether or not an abnormality has occurred in the circulation pump. [Effects of the Invention]

[0013] According to this invention, it is possible to accurately determine whether or not there is a malfunction in the circulation pump. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a side view showing a vehicle equipped with a fuel cell module. [Figure 2] Figure 2 is a schematic diagram showing a fuel cell module. [Figure 3] Figure 3 is a flowchart showing the processing procedure performed by the control device. [Figure 4] Figure 4 is a timing chart showing the phases, circulation pump, injector, and internal pressure of the supply channel. [Modes for carrying out the invention]

[0015] The following describes embodiments of the fuel cell module and the vehicle equipped with the fuel cell module with reference to the drawings. In this embodiment, the vehicle equipped with the fuel cell module is a forklift. For the sake of explanation, the description of the vehicle equipped with the fuel cell module will be given before the description of the fuel cell module.

[0016] <Forklift> As shown in FIG. 1, a forklift 100 as a vehicle includes a vehicle body 101 and a vehicle load 102. The vehicle load 102 is driven by electric power supplied from a fuel cell module 10. An example of the vehicle load 102 is a travel motor 103 and a handling motor 104. The travel motor 103 drives the drive wheels 105 of the vehicle body 101. The handling motor 104 drives a handling device 106. The vehicle body 101 has a housing portion 107. The fuel cell module 10 is housed in the housing portion 107. Thus, the forklift 100 as a vehicle is equipped with the fuel cell module 10.

[0017] As shown in FIG. 2, the forklift 100 includes a key switch 15. The key switch 15 is operated by a user of the forklift 100. By the operation of the user, the on and off states of the key switch 15 are switched. In the following description, the case where the key switch 15 is turned on may be referred to as key-on, and the case where the key switch 15 is turned off may be referred to as key-off.

[0018] <Fuel cell module> The fuel cell module 10 includes an anode system 60, an electric system 90, and a diluter 69. The fuel cell module 10 includes a fuel cell stack 21. The fuel cell stack 21 is, for example, a solid polymer fuel cell. The fuel cell stack 21 includes a plurality of fuel cells 22. The fuel cell 22 includes an anode electrode to which anode gas is supplied, a cathode electrode to which cathode gas is supplied, and an electrolyte membrane disposed between the anode electrode and the cathode electrode. The fuel cell 22 is sandwiched by separators.

[0019] The fuel cell module 10 includes a cathode system (not shown). The cathode system includes, for example, a cathode flow path (not shown) through which cathode gas flows. The cathode flow path is provided, for example, in a separator facing the cathode electrode in the fuel cell stack 21.

[0020] The anode system 60 includes an anode flow path 26 through which anode gas flows. The anode flow path 26 is provided, for example, in a separator facing the anode electrode in the fuel cell stack 21.

[0021] The fuel cell stack 21 generates electricity by the reaction between the anode gas as the fuel gas flowing through the anode flow path 26 and the cathode gas flowing through the cathode flow path. Therefore, the fuel cell stack 21 generates electricity using the fuel gas. Note that the anode gas as the fuel gas is hydrogen gas. The cathode gas is oxygen gas.

[0022] The cathode system includes a cathode supply flow path (not shown). A gas containing the cathode gas flows through the cathode supply flow path. The gas containing the cathode gas is, for example, air. The gas containing the cathode gas is supplied to the cathode flow path through the cathode supply flow path. Thereby, the cathode gas is supplied to the fuel cell stack 21. An electric compressor (not shown) is provided in the cathode supply flow path.

[0023] The cathode system includes an exhaust flow path (not shown). One end of the exhaust flow path is connected to the downstream end of the cathode flow path, and the other end of the exhaust flow path is connected to the diluter 69. Cathode exhaust gas flows into the exhaust flow path from the cathode flow path. The cathode exhaust gas contains unreacted oxygen gas and generated water. The cathode exhaust gas is supplied to the diluter 69 through the exhaust flow path.

[0024] The anode system 60 includes a hydrogen tank 61, a main stop valve 12, an injector 62, an upstream flow path 63 provided upstream of the injector 62, a downstream flow path 64, a gas-liquid separator 65, a circulation pump 66, and an exhaust and drain valve 67. In other words, the fuel cell module 10 includes an injector 62 and a circulation pump 66.

[0025] Hydrogen gas is stored in the hydrogen tank 61. One end of the upstream channel 63 is connected to the injector 62, and the other end of the upstream channel 63 is connected to the hydrogen tank 61. The injector 62 injects hydrogen gas as fuel gas. The injector 62 is a component for adjusting the amount of hydrogen gas supplied to the fuel cell stack 21. The amount of hydrogen gas supplied to the fuel cell stack 21 is adjusted by controlling the injector 62.

[0026] The main shut-off valve 12 is located in the upstream flow path 63. The main shut-off valve 12 is, for example, an electromagnetic shut-off valve. When the main shut-off valve 12 is open, hydrogen gas flows from the upstream side of the main shut-off valve 12 to the downstream side in the upstream flow path 63. When the main shut-off valve 12 is closed, hydrogen gas does not flow from the upstream side of the main shut-off valve 12 to the downstream side in the upstream flow path 63. When the main shut-off valve 12 is open, hydrogen gas is supplied from the hydrogen tank 61 to the injector 62 via the upstream flow path 63.

[0027] The downstream flow path 64 includes a supply flow path 64a, a circulation flow path 64b, and an anode flow path 26. That is, the fuel cell module 10 is equipped with a supply flow path 64a and a circulation flow path 64b. One end of the supply flow path 64a is connected to the injector 62, and the other end of the supply flow path 64a is connected to the upstream end of the anode flow path 26. One end of the circulation flow path 64b is connected to the downstream end of the anode flow path 26, and the other end of the circulation flow path 64b is connected between the two ends of the supply flow path 64a.

[0028] Hydrogen gas injected from the injector 62 flows into the supply channel 64a. The hydrogen gas is supplied to the anode channel 26 via the supply channel 64a. In other words, the supply channel 64a supplies hydrogen gas, which is injected from the injector 62 as fuel gas, to the fuel cell stack 21.

[0029] Anode exhaust gas flows into the circulation channel 64b from the anode channel 26. The anode exhaust gas contains unreacted hydrogen gas and generated water. The generated water is water produced by the power generation in the fuel cell stack 21. The unreacted hydrogen gas contained in the anode exhaust gas is returned to the supply channel 64a via the circulation channel 64b. Therefore, the circulation channel 64b circulates the hydrogen gas, which is discharged from the fuel cell stack 21 as fuel gas, back to the supply channel 64a. The hydrogen gas circulates in the order of supply channel 64a, anode channel 26, and circulation channel 64b.

[0030] The gas-liquid separator 65 is located in the circulation channel 64b. The gas-liquid separator 65 separates the anode exhaust gas into hydrogen gas and generated water. The generated water separated from the anode exhaust gas is stored in the gas-liquid separator 65. The circulation pump 66 is located in the circulation channel 64b. The circulation pump 66 supplies the hydrogen gas separated from the anode exhaust gas by the gas-liquid separator 65 to the supply channel 64a.

[0031] The exhaust and drain valve 67 is connected to the gas-liquid separator 65. The exhaust and drain valve 67 can be switched between an open state and a closed state. When the exhaust and drain valve 67 is open, the generated water is discharged from the gas-liquid separator 65. The exhaust and 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 exhaust and drain valve 67 may be switched from the closed state to the open state at predetermined time intervals. When the exhaust and drain valve 67 is open, the anode exhaust gas in the circulation channel 64b is exhausted to the downstream channel 64 along with the generated water stored in the gas-liquid separator 65.

[0032] The gas-liquid separator 65 is connected to the diluent 69. When the exhaust 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 dilutes the anode exhaust gas supplied from the gas-liquid separator 65 with cathode exhaust gas supplied to the diluent 69 from the discharge channel and then discharges it.

[0033] The diluent 69 is connected to an outlet 39. The anode exhaust gas, diluted by the cathode exhaust gas in the diluent 69, is discharged from the outlet 39. The electrical system 90 comprises a DC / DC converter 91, an energy storage device 96, and a contactor 92. The DC / DC converter 91 is connected to the fuel cell stack 21. The DC / DC converter 91 transforms and outputs the output voltage of the fuel cell stack 21. The output power from the DC / DC converter 91 is supplied to the vehicle load 102. The contactor 92 is connected in series with the vehicle load 102.

[0034] The energy storage device 96 is connected to the DC / DC converter 91. The energy storage device 96 is connected in parallel to the DC / DC converter 91 with the auxiliary equipment 97. When the output power from the DC / DC converter 91 exceeds the power consumption of the vehicle load 102 and the auxiliary equipment 97, the energy storage device 96 is charged with the surplus power. When the output power from the DC / DC converter 91 is less than the power consumption of the vehicle load 102 and the auxiliary equipment 97, the energy storage device 96 discharges. Any type of energy storage device 96 can be used as long as it is capable of charging and discharging. Examples of energy storage devices 96 include secondary batteries and capacitors. The auxiliary equipment 97 includes, for example, an electric compressor in the cathode system, a circulation pump 66, a main shut-off valve 12, an exhaust drain valve 67, and an injector 62.

[0035] The fuel cell module 10 is equipped with an internal pressure sensor 42. The internal pressure sensor 42 detects the internal pressure of the supply channel 64a. In this embodiment, the internal pressure sensor 42 detects the internal pressure between the end of the supply channel 64a connected to the injector 62 and the portion connected to the circulation channel 64b.

[0036] <Control device> The fuel cell module 10 includes a control device 80. The control device 80 includes 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 device 80 may be composed of hardware circuits such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The control device 80, which is a processing circuit, may include one or more processors that operate according to a computer program, one or more hardware circuits such as an ASIC or FPGA, or a combination thereof.

[0037] The control device 80 performs various controls based on the outputs from various detection units and various switches. The various detection units include the internal pressure sensor 42. The various switches include the key switch 15.

[0038] The control device 80 controls the fuel cell module 10. For example, the control device 80 controls the output power [kW] of the fuel cell stack 21. The output power of the fuel cell stack 21 changes depending on the amount of cathode gas supplied to the fuel cell stack 21 and the amount of hydrogen gas supplied to the fuel cell stack 21. The control device 80 controls the injection of hydrogen gas from the injector 62. This controls the amount of hydrogen gas supplied to the fuel cell stack 21. The control device 80 controls the amount of cathode gas supplied to the fuel cell stack 21 by controlling the electric compressor in the cathode system. The control device 80 controls the opening and closing of the exhaust drain valve 67. The control device 80 controls the opening and closing of the main shut-off valve 12. The control device 80 controls the drive of the circulation pump 66.

[0039] The control device 80 controls the ON state of the contactor 92. The contactor 92 connects the fuel cell stack 21 and the vehicle load 102. When the contactor 92 is in the OFF state, the connection between the fuel cell stack 21 and the vehicle load 102 is disconnected. As a result, the supply of power from the fuel cell stack 21 to the vehicle load 102 is stopped. When the contactor 92 is in the ON state, the fuel cell stack 21 and the vehicle load 102 are connected. As a result, power is supplied from the fuel cell stack 21 to the vehicle load 102.

[0040] The control device 80 stops the power generation of the fuel cell stack 21 by stopping the supply of hydrogen gas and cathode gas to the fuel cell stack 21. The control device 80 stops the power generation of the fuel cell stack 21, for example, when the key is turned off. When the power generation of the fuel cell stack 21 is stopped, the control device 80 stops the injection of hydrogen gas from the injector 62, closes the main shut-off valve 12, stops the operation of the circulation pump 66, and closes the exhaust and drain valve 67. When the power generation of the fuel cell stack 21 is stopped, the control device 80 stops the operation of the electric compressor in the cathode system, for example. Furthermore, when the power generation of the fuel cell stack 21 is stopped, the control device 80 may close an on-off valve (not shown) provided in the cathode supply passage.

[0041] The control device 80 generates electricity in the fuel cell stack 21 by supplying oxygen gas and hydrogen gas to the fuel cell stack 21. The control device 80 starts power generation in the fuel cell stack 21 by starting the operation of the fuel cell module 10, for example, when the key is turned on. When power generation in the fuel cell stack 21 is started, the control device 80 starts the injection of hydrogen gas from the injector 62, opens the main shut-off valve 12, and starts the operation of the circulation pump 66. When power generation in the fuel cell stack 21 is started, the control device 80 drives the electric compressor in the cathode system, for example. Furthermore, when power generation in the fuel cell stack 21 is started, the control device 80 may open an on-off valve (not shown) provided in the cathode supply channel.

[0042] When the control device 80 starts driving the fuel cell module 10, it changes the processing content by switching phases in the order of Phase 1, Phase 2, Phase 3, and Phase 4. In Phase 1, the control device 80 determines whether or not there are any malfunctions in the various detection units. In Phase 2, the control device 80 waits for various controls to be performed until the contactor 92 is turned ON. In Phase 3, the control device 80 starts driving the circulation pump 66 and injecting hydrogen gas from the injector 62, and also opens the main shut-off valve 12. Specifically, in Phase 3, the control device 80 starts driving the circulation pump 66 and then starts injecting hydrogen gas from the injector 62. In Phase 4, the control device 80 starts driving the electric compressor in the cathode system, and then the power generation of the fuel cell stack 21 is started.

[0043] <Anomaly detection process> The control device 80 performs an abnormality determination process to determine whether or not there is an abnormality in the circulation pump 66. The control device 80 performs an abnormality determination process based on the start of operation of the fuel cell module 10. The control device 80 performs an abnormality determination process each time the fuel cell module 10 starts operating.

[0044] The control device 80 performs an abnormality determination process to determine whether or not an abnormality has occurred in the circulation pump 66 based on the first internal pressure P1 and the second internal pressure P2. The first internal pressure P1 is the internal pressure of the supply channel 64a detected by the internal pressure sensor 42 during the first period T1. The second internal pressure P2 is the internal pressure of the supply channel 64a detected by the internal pressure sensor 42 during the second period T2.

[0045] The first period T1 is the period after the start of operation of the fuel cell module 10, before the start of injection of hydrogen gas as fuel gas from the injector 62, and before the start of operation of the circulation pump 66. The first period T1 is included in the period from the start of operation of the fuel cell module 10 until the contactor 92 turns ON. In this embodiment, the first period T1 is the period in the second phase. For example, the first period T1 may be set to be shorter than the period set in the second phase. In this case, the first period T1 may be the period from a predetermined time after the phase transition to the second phase until the end of the second phase.

[0046] The memory unit 82 stores the average value of the first internal pressure P1 detected multiple times from the internal pressure sensor 42 during the first period T1 as the average internal pressure PA1. Specifically, the control device 80 stores the first internal pressure P1 detected from the internal pressure sensor 42 at regular intervals during the first period T1, thereby storing the first internal pressure P1 as multiple detection results. The control device 80 calculates the average internal pressure PA1 by averaging the multiple first internal pressures P1 stored in the memory unit 82. The memory unit 82 stores the calculated average internal pressure PA1. The average internal pressure PA1 stored in the memory unit 82 is reset when the operation of the fuel cell module 10 is stopped. Therefore, each time the operation of the fuel cell module 10 is started, the average internal pressure PA1 for the first period T1 is calculated and stored in the memory unit 82.

[0047] The second period T2 is a period that is later than the first period T1, before the injection of hydrogen gas as fuel gas from the injector 62 begins, and after a predetermined period Tp1 has elapsed since the start of operation of the circulation pump 66. In this embodiment, the second period T2 is a period in the third phase that is after a predetermined period Tp1 has elapsed since the start of operation of the circulation pump 66, and before the injection of hydrogen gas from the injector 62 begins.

[0048] In the abnormality detection process, the control device 80 repeatedly performs the following during the second period T2: acquiring the second internal pressure P2 from the internal pressure sensor 42 and performing a determination process to determine whether the difference D between the acquired second internal pressure P2 and the average internal pressure PA1 stored in the storage unit 82 is less than a predetermined value Pt. The control device 80 determines that an abnormality has occurred in the circulation pump 66 if the determination process determines that the difference D is less than the predetermined value Pt for a predetermined time Tp2. Specifically, the control device 80 acquires the second internal pressure P2 detected from the internal pressure sensor 42 at regular intervals during the second period T2. The control device 80 performs the determination process each time the second internal pressure P2 is acquired. The control device 80 determines that an abnormality has occurred in the circulation pump 66 if the acquisition of the second internal pressure P2 and the determination that the difference D in the determination process based on the acquired second internal pressure P2 is less than the predetermined value Pt occur consecutively for a predetermined time Tp2.

[0049] The control device 80 repeatedly performs the acquisition of the second internal pressure P2 and the judgment process without determining an abnormality in the circulation pump 66 if the difference D in the judgment process is greater than or equal to a predetermined value Pt, or if the duration of the judgment that the difference D is less than the predetermined value Pt is less than a predetermined time Tp2. This repetition of acquiring the second internal pressure P2 and the judgment process is performed from the time a predetermined period Tp1 has elapsed from the start of operation of the circulation pump 66 until the second period T2 has elapsed. If, by the time the second period T2 has elapsed, the control device 80 has not made a judgment that the difference D is less than the predetermined value Pt for a predetermined time Tp2, it determines that there is no abnormality in the circulation pump 66 and that it is functioning normally. In the abnormality determination process, the control device 80 performs either an abnormality determination of the circulation pump 66 or a normal determination of the circulation pump 66, and then terminates the abnormality determination process.

[0050] <Anomaly detection process> In this embodiment, the control device 80 performs an abnormality confirmation process following the abnormality detection process. In the abnormality confirmation process, the control device 80 counts or resets the number of determinations C according to the determination result from the abnormality detection process. Specifically, if the control device 80 determines in the abnormality detection process that there is an abnormality in the circulation pump 66, it counts the number of determinations C. As a result, the number of determinations C is incremented by "1" each time the abnormality detection process determines that there is an abnormality in the circulation pump 66. If the control device 80 determines in the abnormality detection process that there is no abnormality in the circulation pump 66, it resets the number of determinations C. As a result, the number of determinations C is reset to "0" when the abnormality detection process determines that the circulation pump 66 is normal.

[0051] In the abnormality confirmation process, the control device 80 confirms that an abnormality has occurred in the circulation pump 66 if the number of judgments C is 2 or more than a predetermined number Cp. The predetermined number Cp is set to a value of 2 or more and is a value that has been set in advance through experiments or the like. In the abnormality confirmation process, if the number of judgments C is less than the predetermined number Cp, the control device 80 terminates the abnormality confirmation process without confirming an abnormality in the circulation pump 66.

[0052] Each time the fuel cell module 10 starts operating, the control device 80 performs an abnormality detection process and an abnormality confirmation process. This process is repeated, so that each time the fuel cell module 10 starts operating, the control device 80 either counts the number of detections C or resets the number of detections C. As the fuel cell module 10 starts operating multiple times, the count of the number of detections C continues, and the number of detections C reaches a predetermined number Cp.

[0053] <An example of processing by a control device> An example of the processing performed by the control device 80 is explained with reference to Figure 3. The processing shown in Figure 3 is executed once, provided that the key is turned on.

[0054] As shown in Figure 3, once processing begins, the control device 80 determines whether or not there is a malfunction in any of the detection units (step S110). If it determines that there is a malfunction in any of the detection units, the control device 80 terminates this process. If it determines that there is no malfunction in any of the detection units (step S110: YES), it stores the average internal pressure PA1 (step S120). Here, the control device 80 calculates the average internal pressure PA1 based on the first internal pressure P1 detected from the internal pressure sensor 42, and the storage unit 82 of the control device 80 stores the calculated average internal pressure PA1. After that, the control device 80 determines whether or not a predetermined period Tp1 has elapsed since the start of operation of the circulation pump 66 (step S130). If it determines that a predetermined period Tp1 has not elapsed since the start of operation of the circulation pump 66 (step S130: NO), the control device 80 repeats the process in step S130. That is, the control device 80 repeatedly performs the process in step S130 as long as it is not determined to be YES in step S130.

[0055] If the control device 80 determines that a predetermined period Tp1 has elapsed since the start of operation of the circulation pump 66 (step S130: YES), it determines whether a second period T2 has elapsed since the predetermined period Tp1 elapsed since the start of operation of the circulation pump 66 (step S140). If the control device 80 determines that a second period T2 has not elapsed (step S140: NO), it obtains a second internal pressure P2, which is the internal pressure detected from the internal pressure sensor 42 (step S150). Subsequently, the control device 80 determines whether the difference D between the second internal pressure P2 obtained in step S150 and the average internal pressure PA1 stored in the storage unit 82 is less than a predetermined value Pt (step S160). If the control device 80 determines that the difference D is less than the predetermined value Pt (step S160: YES), it determines whether the determination that the difference D is less than the predetermined value Pt has been made continuously for a predetermined time Tp2 (step S170). When it is determined that the difference D is greater than or equal to a predetermined value Pt (step S160: NO), or when it is determined that the difference D is less than the predetermined value Pt for a predetermined time Tp2 consecutively (step S170: NO), the control device 80 repeats the process of step S140. That is, as long as it is not determined to be YES in step S170, the process of step S140 is repeated. As long as it is not determined in step S140 that the second period T2 has elapsed, the processes of steps S150 to S170 are repeated.

[0056] If the control device 80 determines that the difference D is less than a predetermined value Pt for a predetermined period of time Tp2 consecutively (step S170: YES), it determines that there is an abnormality in the circulation pump 66 (step S180). Subsequently, the control device 80 counts the number of determinations C (step S190).

[0057] Next, the control device 80 determines whether the number of judgments C is a predetermined number Cp (step S200). If it determines that the number of judgments C is not a predetermined number Cp (step S200: NO), the control device 80 terminates the process. If it determines that the number of judgments C is a predetermined number Cp (step S200: YES), the control device 80 confirms the abnormality of the circulation pump 66 (step S210) and then terminates the process.

[0058] When it is determined that the second period T2 has elapsed (step S140: YES), the control device 80 determines that there is no abnormality in the circulation pump 66 and that it is functioning normally (step S220). After that, the control device 80 resets the number of determinations C (step S230) and then terminates this process.

[0059] In the process shown in Figure 3, steps S110 to S180 and step S220 correspond to the abnormality detection process. Step S160 corresponds to the decision process. Steps S190 to S210 and step S230 correspond to the abnormality confirmation process.

[0060] [Effect of the Embodiment] Next, the operation of this embodiment will be described. As shown in Figure 4, when the fuel cell module 10 is started to operate, the phases progress in the order of Phase 1, Phase 2, Phase 3, and Phase 4. Between time t1 and time t2, it is set to Phase 2. During the first period T1 in Phase 2, the memory unit 82 of the control device 80 stores the average value of the first internal pressure P1 detected multiple times from the internal pressure sensor 42 as the average internal pressure PA1. At time t2, the contactor 92 is turned ON and the circulation pump 66 is turned ON from its stopped OFF state and starts to operate.

[0061] The third phase is set between time t2 and time t6. The time between time t2 and time t3 in the third phase corresponds to a predetermined period Tp1. During this predetermined period Tp1, the internal pressure of the supply channel 64a increases due to the operation of the circulation pump 66.

[0062] The time between time t3 and time t4 corresponds to the second period T2. Between time t3 and time t4, the control device 80 repeatedly performs the following: acquiring the second internal pressure P2 and determining whether the difference D between the acquired second internal pressure P2 and the average internal pressure PA1 stored in the storage unit 82 is less than a predetermined value Pt. Between time t3 and time t4, if the determination process determines that the difference D is less than the predetermined value Pt for a predetermined time Tp2, the control device 80 determines that there is an abnormality in the circulation pump 66. If, by time t4, that is, from the start of operation of the circulation pump 66 until the end of the second period T2, the difference D is not determined to be less than the predetermined value Pt for a predetermined time Tp2, the control device 80 determines that there is no abnormality in the circulation pump 66 and that it is functioning normally.

[0063] The internal pressure of the supply channel 64a increases as the circulation pump 66 starts to operate. Therefore, if the circulation pump 66 is operating normally, the internal pressure of the supply channel 64a in the second period T2 will be higher than the internal pressure of the supply channel 64a in the first period T1. The control device 80 performs an abnormality determination process to determine whether or not there is an abnormality in the circulation pump 66 based on the first internal pressure P1, which is the internal pressure of the supply channel 64a detected in the first period T1, and the second internal pressure P2, which is the internal pressure of the supply channel 64a detected in the second period T2. Thus, it is possible to determine whether or not there is an abnormality in the circulation pump 66 based on the change in the internal pressure of the supply channel 64a before and after the start of operation of the circulation pump 66.

[0064] At time t5, which is later than time t4, the injection of hydrogen gas as fuel gas from the injector 62 begins. Therefore, the control device 80 can obtain the first internal pressure P1 and the second internal pressure P2 from the internal pressure sensor 42 before the injection of hydrogen gas from the injector 62 begins. From time t5 onward, the internal pressure of the supply channel 64a increases compared to before time t5 due to the operation of the circulation pump 66 and the injection from the injector 62. From time t6 onward, the system is set to the fourth phase. In the fourth phase, power generation by the fuel cell stack 21 begins.

[0065] [Effects of the Embodiment] According to the above embodiment, the following effects can be obtained. (1) The control device 80 performs an abnormality determination process to determine whether or not an abnormality has occurred in the circulation pump 66 based on the first internal pressure P1 and the second internal pressure P2. The first internal pressure P1 is the internal pressure of the supply passage 64a detected by the internal pressure sensor 42 during the first period T1. The second internal pressure P2 is the internal pressure of the supply passage 64a detected by the internal pressure sensor 42 during the second period T2. Both the first period T1, when the first internal pressure P1 is detected, and the second period T2, when the second internal pressure P2 is detected, are periods before the injection of hydrogen gas as fuel gas from the injector 62 begins. During the period before the injection of hydrogen gas as fuel gas from the injector 62 begins, there is no fluctuation in the internal pressure of the supply passage 64a caused by the injection of hydrogen gas as fuel gas from the injector 62. Therefore, by performing abnormality detection processing based on the first internal pressure P1 and the second internal pressure P2, abnormality detection processing can be performed based on fluctuations in the internal pressure of the supply channel 64a under conditions where fluctuations in the internal pressure of the supply channel 64a caused by factors other than the operation of the circulation pump 66 are unlikely to occur.

[0066] Furthermore, the first period T1 in which the first internal pressure P1 is detected is the period before the start of operation of the circulation pump 66. Therefore, the first internal pressure P1 is the internal pressure of the supply channel 64a when there is no change in the internal pressure of the supply channel 64a due to the operation of the circulation pump 66. The second period T2 in which the second internal pressure P2 is detected is the period after a predetermined period Tp1 has elapsed since the start of operation of the circulation pump 66. Therefore, the second internal pressure P2 is the internal pressure of the supply channel 64a when there is a change in the internal pressure of the supply channel 64a due to the operation of the circulation pump 66. In the abnormality determination process, the control device 80 determines whether or not an abnormality has occurred in the circulation pump 66 based on the first internal pressure P1 and the second internal pressure P2. This makes it possible to determine whether or not an abnormality has occurred in the circulation pump 66 based on the change in the internal pressure of the supply channel 64a due to the operation of the circulation pump 66. Therefore, it is possible to determine whether or not an abnormality has occurred in the circulation pump 66 with high accuracy.

[0067] (2) The control device 80 performs an abnormality determination process each time the fuel cell module 10 is started to operate. If the control device 80 determines in the abnormality determination process that there is an abnormality in the circulation pump 66, it counts the determination count C. If the control device 80 determines in the abnormality determination process that there is no abnormality in the circulation pump 66, it resets the determination count C. If the determination count C is 2 or more than a predetermined number Cp, the control device 80 confirms that there is an abnormality in the circulation pump 66. Therefore, the control device 80 does not confirm that there is an abnormality in the circulation pump 66 until the determination count C reaches the predetermined number Cp. Thus, if the abnormality determination process determines that there is an abnormality in the circulation pump 66 due to a factor other than an abnormality in the circulation pump 66, it is possible to suppress the confirmation that there is an abnormality in the circulation pump 66.

[0068] (3) The control device 80 includes a storage unit 82 that stores the average value of the first internal pressure P1 detected multiple times from the internal pressure sensor 42 during the first period T1 as the average internal pressure PA1. In the abnormality determination process, the control device 80 repeatedly performs the following during the second period T2: acquiring the second internal pressure P2 from the internal pressure sensor 42 and performing a determination process to determine whether the difference D between the acquired second internal pressure P2 and the average internal pressure PA1 stored in the storage unit 82 is less than a predetermined value Pt. The control device 80 determines that there is an abnormality in the circulation pump 66 on the condition that the determination process determines that the difference D is less than the predetermined value Pt for a predetermined time Tp2. Therefore, the control device 80 does not determine that there is an abnormality in the circulation pump 66 as long as the determination process does not determine that the difference D is less than the predetermined value Pt for a predetermined time Tp2. Thus, in the abnormality determination process, it is possible to suppress the determination that there is an abnormality in the circulation pump 66 when the difference D temporarily falls below the predetermined value Pt due to factors other than an abnormality in the circulation pump 66.

[0069] (4) The forklift 100 as a vehicle is equipped with a vehicle load 102 that is driven by electricity supplied from the fuel cell module 10. The control device 80 performs abnormality determination processing based on the start of operation of the fuel cell module 10. The first period T1 includes the period from the start of operation of the fuel cell module 10 until the contactor 92 connecting the fuel cell stack 21 and the vehicle load 102 is turned ON. Therefore, the control device 80 can obtain the first internal pressure P1 used for abnormality determination processing during the period from the start of operation of the fuel cell module 10 until the contactor 92 is turned ON. Thus, the period from the start of operation of the fuel cell module 10 until the contactor 92 is turned ON can be used as a period for determining whether or not an abnormality has occurred in the circulation pump 66.

[0070] (5) If an upstream internal pressure sensor is provided upstream of the circulation pump 66 in the circulation channel 64b, it is possible to determine if there is an abnormality in the circulation pump 66 based on the pressure difference between the upstream internal pressure sensor and the internal pressure sensor 42, but the upstream internal pressure sensor must be provided in the circulation channel 64b. According to the embodiment, it is possible to determine if there is an abnormality in the circulation pump 66 based on the internal pressure of the supply channel 64a detected by the internal pressure sensor 42. Therefore, the number of parts in the fuel cell module 10 can be reduced by the amount by which the above-mentioned upstream internal pressure sensor can be omitted from the circulation channel 64b.

[0071] [Example of changes] The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0072] ○ The location where the internal pressure sensor 42 detects internal pressure is not limited to the portion of the supply channel 64a between the end connected to the injector 62 and the portion connected to the circulation channel 64b. For example, the internal pressure sensor 42 may detect internal pressure in the portion of the supply channel 64a downstream of the portion connected to the circulation channel 64b.

[0073] ○ Step S110 may be omitted from the process shown in Figure 3. ○ The first period T1 does not necessarily have to be included in the period from the start of operation of the fuel cell module 10 until the contactor 92 connecting the fuel cell stack 21 and the vehicle load 102 is turned ON. For example, the first period T1 may be included in the period from the moment the contactor 92 is turned ON from the OFF state until the operation of the circulation pump 66 is started.

[0074] ○The control device 80 may perform abnormality detection processing based on conditions other than the start of operation of the fuel cell module 10. For example, abnormality detection processing may be performed based on the condition that a predetermined amount of time has elapsed since the start of operation of the fuel cell module 10.

[0075] ○ In the abnormality determination process, the control device 80 may determine that an abnormality has occurred in the circulation pump 66 if, in the second period T2, the determination process determines at least once that the difference D is less than a predetermined value Pt. In this case, step S170 may be omitted from the process shown in Figure 3.

[0076] ○ In the decision-making process, the control device 80 may determine whether the difference D between the acquired second internal pressure P2 and the first internal pressure P1 is less than a predetermined value. In this case, the control device 80 may, for example, acquire the first internal pressure P1 detected from the internal pressure sensor 42 during the first period T1. The decision-making process may be performed using this acquired first internal pressure P1. Alternatively, in step S160 shown in Figure 3, the control device 80 may determine whether the difference D between the acquired second internal pressure P2 and the first internal pressure P1 is less than a predetermined value. In step S120, the storage unit 82 may store the first internal pressure P1.

[0077] ○ The control device 80 may omit counting the number of judgments C, resetting the number of judgments C, and confirming that there is an abnormality in the circulation pump 66 based on the number of judgments C. In this case, steps S190 to S210 and step S230 may be omitted from the process shown in Figure 3.

[0078] ○ Fuel gas is not limited to hydrogen gas. ○ The fuel cell module 10 may be installed in passenger cars, ships, trains, etc. ○ The fuel cell module 10 may also be used as a stationary power generation device. [Explanation of Symbols]

[0079] C...Number of judgments, Cp...Determined number of times, D...Difference, Tp1...Determined period, Tp2...Determined time, T1...First period, T2...Second period, PA1...Average internal pressure, P1...First internal pressure, P2...Second internal pressure, Pt...Determined value, 10...Fuel cell module, 21...Fuel cell stack, 42...Internal pressure sensor, 62...Injector, 64a...Supply channel, 64b...Circulation channel, 66...Circulation pump, 80...Control device, 82...Storage unit, 92...Contactor, 100...Forklift as a vehicle, 102...Vehicle load.

Claims

1. A fuel cell stack that generates electricity using fuel gas, An injector that injects fuel gas, A supply channel for supplying fuel gas injected from the injector to the fuel cell stack, A circulation channel for circulating fuel gas discharged from the fuel cell stack to the supply channel, An internal pressure sensor for detecting the internal pressure of the supply channel, A circulation pump provided in the aforementioned circulation channel, A fuel cell module comprising a control device for controlling the drive of the circulation pump, The control device performs an abnormality determination process to determine whether or not an abnormality has occurred in the circulation pump, based on a first internal pressure, which is the internal pressure of the supply channel detected by the internal pressure sensor during the first period, and a second internal pressure, which is the internal pressure of the supply channel detected by the internal pressure sensor during the second period. The first period is the period after the start of operation of the fuel cell module, and before the start of fuel gas injection from the injector, and before the start of operation of the circulation pump. The fuel cell module is characterized in that the second period is a period later than the first period, a period before the start of fuel gas injection from the injector, and a period after a predetermined period has elapsed since the start of operation of the circulation pump.

2. The control device is Each time the operation of the fuel cell module is started, the abnormality determination process is performed. If the abnormality detection process determines that an abnormality has occurred in the circulation pump, the number of detection attempts is counted. If the abnormality detection process determines that there is no abnormality in the circulation pump, the number of detection attempts is reset. The fuel cell module according to claim 1, wherein if the number of determinations is two or more predetermined times, it is determined that there is an abnormality in the circulation pump.

3. The control device includes a storage unit that stores the average value of the first internal pressure detected multiple times from the internal pressure sensor during the first period as the average internal pressure. The fuel cell module according to claim 1 or 2, wherein in the abnormality determination process, the acquisition of the second internal pressure from the internal pressure sensor and the determination process of determining whether the difference between the acquired second internal pressure and the average internal pressure stored in the storage unit is less than a predetermined value are repeatedly performed in the second period, and it is determined that an abnormality has occurred in the circulation pump if the determination process continuously determines that the difference is less than the predetermined value for a predetermined time.

4. A vehicle equipped with a fuel cell module according to claim 1 or claim 2, The vehicle is equipped with a vehicle load that is driven by electricity supplied from the fuel cell module. The control device is The abnormality determination process is performed based on the start of operation of the fuel cell module. A vehicle equipped with a fuel cell module, characterized in that the first period includes the period from the start of operation of the fuel cell module until the contactor connecting the fuel cell stack and the vehicle load is turned on.

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